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1
Theron, Dirk Leopold. "The biological control of malaria mosquito larvae using smaller indigenous freshwater fish species." Thesis, University of Limpopo, 1987. http://hdl.handle.net/10386/2611.
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Anderson, Laura Fay. "Malaria proteins implicated in host-parasite interactions." Thesis, University of Edinburgh, 2007. http://hdl.handle.net/1842/1965.
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The invasive and transmission stages of the malaria parasite Plasmodium falciparum express several proteins with domains implicated in host-parasite interactions, that are potential vaccine candidates or drug targets. The expression patterns of two proteins PfTRAMP (Plasmodium Related Apical Merozoite Protein) and PCRAGS (Plasmodium cysteine related antigen of gametocytes and schizonts), containing such putative domains, are examined and their potential roles in merozoite invasion and egress are discussed. PfTRAMP has a possible role in merozoite invasion. Transcription occurs in mature schizonts as shown by Northern blot. Recombinant protein was successfully expressed in insect cells indicating that this eukaryotic system can be utilised for the expression of Plasmodium proteins. PCRAGS is a member of the Plasmodium Cysteine Repeat Modular Proteins (PCRMPs), a family of high molecular weight proteins with highly conserved, cysteine-rich regions and multipass transmembrane domains. The gene encodes a signal sequence, a truncated extracellular domain, an EGF-like domain and a multipass-transmembrane domain. PCRAGS is highly conserved in Plasmodium spp and other Apicomplexa. The extracellular domain has been under purifying selection, suggesting that the sequence or the structure of this domain is important for function. The gene is transcribed throughout the asexual erythrocytic cycle and is expressed in both gametocytes and schizonts in P. falciparum and in the rodent malaria P.berghei. Antibodies raised against a short peptide in the C-terminus detect PfCRAGS during schizont rupture and in mature segmenting schizonts but not in merozoites. Western blotting showed that PfCRAGS is present in the membrane fraction. Co-localisation studies showed that PfCRAGS is associated with the infected erythrocyte membrane, suggesting a role in merozoite egress. PfCRAGS is also expressed in stage II-IV male gametocytes in association with a membrane and is the earliest known male specific protein expressed. Gene knock-out of pbcrags in P. berghei showed that PbCRAGS is not essential for asexual development. In vivo evaluation of phenotype showed that pbcrags knock-out parasites are less virulent than wildtype parasites and have an increased gametocyte production in a non-susceptible host. The unique expression and localisation pattern of PfCRAGS in combination with putative host-parasite binding domains implicate this novel protein as a potential vaccine candidate or drug target.
3
Wall, Bridget (Bridget Anne). "Engineered tools for studying the malaria parasite plasmodium falciparum." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98923.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Biological Engineering, 2015.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from PDF student-submitted version of thesis.
Includes bibliographical references (pages 120-136).
New techniques to both prevent and treat the disease malaria are necessary. To develop these novel strategies, innovative tools must be designed to study the basic biology within Plasmodium falciparum and characteristics of the pathological relationship between host and parasite. These tools will be diverse in nature, yet all seek to address the same fundamental question: what are the characteristics of the parasite that can be exploited to decrease the burden this parasite places on the human species? First, the relationship between nitric oxide and the parasite-infected red blood cell will be measured using a microfluidic device. Second, a toolkit to determine the essentiality of genes of unknown function will be engineered and tested with three separate genes to improve and demonstrate usability. Third, a mutator strain will be engineered and defined for eventual use in the study of drug resistance and the characterization of the resistance potential of anti-malarial drugs.
by Bridget Wall.
Ph. D.
4
Ng, Shengyong. "Engineering human hepatic tissue for modeling liver-stage malaria." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/90150.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Biological Engineering, 2014.Cataloged from PDF version of thesis. Vita.
Includes bibliographical references (pages 132-153).
The Plcsmodium liver stage is an attractive target for the development of antimalarial drugs and vaccines, as it provides an opportunity to interrupt the life cycle of the parasite at a critical early stage. However, targeting the liver stage has been difficult due to a lack of human liver models that robustly recapitulate host-pathogen interactions in a physiologically relevant cell type. Through the application of hepatic tissue engineering concepts and techniques, this thesis sought to develop advanced models of liver-stage malaria that will allow the facile interrogation of potential antimalarial drugs in primary human hepatocytes. In the first part of this work, we established liver-stage Plasmodium infection in an engineered microscale human liver platform based on micropatterned cocultures of primary human hepatocytes and supportive stromal cells, enabling medium-throughput phenotypic screens for potential antimalarial drugs in a more authentic host cell, and demonstrated the utility of this model for malaria vaccine testing. We further hypothesized and showed that recapitulation of a more physiologically relevant oxygen tension that is experienced by hepatocytes in vivo improved infection rates and parasite growth in vitro. Next, we demonstrated the feasibility of establishing liver-stage malaria infections in human induced pluripotent stem cell-derived hepatocyte-like cells (iHLCs), thus enabling the study of host genetic variation on liver-stage malaria infection and antimalarial drug responses. We also applied recently discovered small molecules to induce further hepatic maturation, thus increasing the utility of using iHLCs for antimalarial drug development. Finally, we designed and provided a proof-of-concept for a humanized mouse model of liver-stage malaria that involves the fabrication and ectopic implantation of PEG-cryogel-based engineered human artificial livers, and can be generated in a facile, rapid and scalable fashion for future preclinical antimalarial drug testing in vivo. The results of this research represent a three-pronged approach towards engineering scalable human liver models that recapitulate liver-stage malaria infection which may ultimately facilitate antimalarial drug discovery at various stages of the drug development pipeline.
by Shengyong Ng.
Ph. D.
5
Long, Gráinne Helen. "Immunopathology and virulence evolution in rodent malaria." Thesis, University of Edinburgh, 2007. http://hdl.handle.net/1842/1962.
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From an evolutionary perspective, natural selection is expected to maximize transmission to new hosts. If a live, mobile host often benefits parasite transmission, the question arises as to why malaria parasites are virulent? The favoured trade-off view of virulence evolution assumes that virulence arises as an unavoidable consequence of parasite resource exploitation within the host that is necessary to maximise parasite transmission. However, virulence is not always a simple function of parasite density and can arise as a result of immune-mediated virulence (immunopathology). This thesis explores how immunopathology contributes to virulence on the one hand, and parasite transmission on the other, in order to improve our understanding of parasite virulence evolution. In tackling this question, the role parasite genetic diversity plays in determining immunopathology induced during malaria infection was also addressed. Using the rodent malaria Plasmodium chabaudi chabaudi (P.c.c.) in C57BL/6 mice, I explored whether immune factors – in terms of specific host cytokines central to the protection-pathology balancing act of the immune response elicited against malaria parasites – help to determine the virulence induced during infection with genetically distinct parasites, and if so, what effect this may have on transmission-stage parasites. I showed that the cytokine milieu induced by P.c.c. parasites during primary infection varies with parasite genotype and that virulence can arise independent of parasite density, via immunopathology. Specifically, I showed propensity to induce the pro-inflammatory cytokine tumour necrosis factor [TNF]-a contributes to the virulence induced, regardless of P.c.c. clone. Importantly, I also showed that across P.c.c. genotype, TNF-a reduces the density of transmission-stage parasites. Thus, virulence is not always a simple function of parasite replication, having an immune-mediated component which acts to reduce transmission potential. The importance of parasite genotype in determining the degree of immunopathological virulence induced during malaria infection was revealed by studying the anti-inflammatory arm of the immune response. The extent to which the anti-inflammatory cytokines interleukin [IL]-10 or transforming growth factor [TGF]-b limited the immunopathology induced during P.c.c. infection depended on parasite clone. In addition, parasite genotype played a key role in determining how such anti-inflammatory manipulations affected the density of transmission-stage parasites; being detrimental, beneficial or incidental to parasite fitness, depending on P.c.c. clone. Although the general mechanisms of immune regulation are qualitatively unchanged across distinct P.c.c. clones, these data emphasize the importance of parasite genotype: distinct clones differ quantitatively in immune regulation, which contributes towards their distinct virulence and fitness schedules. Overall, I found that even within a parasite species – in this case P. chabaudi – the effect of immunopathology on the virulence-transmissibility relationship may be genetically variable and may not conform to that predicted by the trade-off hypothesis, having the potential to alter the costs and benefits of virulence, depending on parasite genotype. Thus, the host immune response may play a role shaping virulence evolution and defining the limit to malaria virulence in nature.
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Goldfless, Stephen J. (Stephen Jacob). "Engineering control of eukaryotic translation with application to the malaria parasite Plasmodium falciparum." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/88903.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Biological Engineering, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 123-130).
Experimenter control of target gene expression is a fundamental component of molecular biology research. In many systems, tools exist that allow generalizable control of gene expression at the transcriptional or post-transcriptional level. Plasmodium falciparum, the protozoan parasite responsible for the majority of death and sickness due to malaria, remains challenging to manipulate in the laboratory. No robust and generalizable tool for gene expression control has been developed in the parasite. To address this need, we engineered a new system for control of protein translation in eukarvotes, and applied it to P. falciparum. This system is based on the ligand-regulated interaction between an RNA aptamers and the TetR-repressor protein. Although such protein-RNA interactions are abundant in nature and are known to effectively mediate control of gene expression, our system is unique in its direct modulation by an exogenous chemical. By genetically encoding TetR-binding RNA aptamers in the 5' untranslated region (5'UTR) of an mRNA, translation of a downstream coding sequence is repressed by TetR in vivo and induced upon adding a non-toxic tetracycline analog. We first define the system's component molecular interactions in vitro, followed by optimization of the constituent parts for convenience and performance. We then further optimize the system and validate its performance in two model systems, the budding yeast Saccharomvces cerevisiae and cell-free rabbit reticulocyte extracts. We show the broad utility of the system in P. falciparum for controlling expression of reporter and endogenous proteins trafficked to a variety of subcellular compartments. Induction and repression are rapid and homogeneous across the cell population. Placing a drug resistance determinant tinder inducible control, we are able to modulate P. falciparum drug sensitivity, demonstrating the usefulness of the system for controlling relevant parasite biology. In the process of constructing and validating a novel tool for gene expression in P. falciparum. we built a new series of gene expression vectors for molecular biology work in the parasite. In addition to developing optimized protocols for plasmid construction, we built a standardized, sequence-defined family of plasmids for malaria research. In all, we present a generalizable, well-defined toolkit for genetic programming of P. falciparum.
by Stephen J. Goldfless.
Ph. D.
7
Birch, Christina M. (Christina Marie). "Identification of malaria parasite-infected red blood cell aptamers by inertial microfluidics SELEX." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98922.
Full textAbstract:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Biological Engineering, 2015.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 95-103).
Malaria kills over 500,000 people annually, the majority of whom are children under five years old in sub-Saharan Africa. This disease is caused by several parasite species, of which Plasmodium falciparum is associated with the highest mortality. The clinical manifestations of malaria are associated with the phase of infection where parasites develop within red blood cells (RBCs). Infected RBCs can adhere to the host microvasculature, triggering inflammatory responses in affected organs that contribute to the pathophysiology of life threatening cerebral malaria and pregnancy-associated malaria. The expression of specific Plasmodium falciparum Erythrocyte Membrane Protein 1 (PfEMP1) variants on the RBC surface is associated with severe disease, such as VAR2CSA-mediated placental sequestration during pregnancy-associated malaria. While parasite proteins expressed on the surface of infected RBCs are linked to disease pathogenesis, this surface proteome is poorly characterized. Identifying parasite-derived antigens on the infected RBC surface could facilitate diagnosis, monitoring, and prevention of sequestration. To interrogate the infected RBC surface proteome, we require a panel of affinity reagents that robustly distinguish the parasite-derived proteins from the elaborate RBC surface milieu. Nucleic acid aptamers are widely used in biological applications for their high specificity and affinity to targets and are highly suitable for malaria applications. Efficiently generating aptamers against complex targets-such as whole cells-remains a challenge. Here we develop a novel strategy (I-SELEX) that utilizes inertial focusing in spiral microfluidic channels to stringently partition cells from unbound oligonucleotides. We use I-SELEX to efficiently discover high affinity aptamers that selectively recognize distinct epitopes present on target cells. Using first an engineered RBC model displaying a non-native antigen and, second, live malaria parasite-infected RBCs as targets, we establish suitability of this strategy for de novo aptamer selections. We demonstrate recovery of a diverse set of aptamers that recognize distinct epitopes on parasite-infected RBCs with nanomolar affinity, including an aptamer against the protein responsible for placental sequestration, VAR2CSA. These findings validate I-SELEX as a broadly applicable aptamer discovery platform that enables identification of new reagents for mapping the parasite-infected RBC surface proteome at higher molecular resolution to potentially contribute to malaria diagnostics, therapeutics and vaccine efforts.
by Christina M. Birch.
Ph. D.
8
Pattaradilokrat, Sittiporn. "Linkage group selection to investigate genetic determinants of complex traits of malaria parasites." Thesis, University of Edinburgh, 2008. http://hdl.handle.net/1842/3139.
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Malaria parasites of the species infecting humans and animal hosts exhibit genetic and phenotypic diversity. Some of this diversity, including the responses to anti-malarial drugs, growth rate and virulence and antigenic variability, is medically significant. This is because these phenotypes may determine the existence and survival of the parasites in the host and, in turn, contribute to the clinical outcome of infection. Understanding of the biological characteristics and the genetic basis underlying these complex phenotypes can thus lead to the development of effective control strategies against the disease, such as anti-malarial drugs and vaccines. Genetic studies in rodent malaria parasites have proved useful in providing insights into the genetic determinants of these complex traits and thus can be used to complement the study of human malaria. The present studies aim to investigate genetic determinants underlying two major medically important phenotypes, Strain Specific Protective Immunity (SSPI) and Growth rate, using the newly devised genetic method of Linkage Group Selection (LGS). The results presented here relate to the accomplishment of these aims. LGS analysis of SSPI using a genetic cross between clones AJ and CB-pyr10 of Plasmodium chabaudi chabaudi has identified a single region on chromosome 8 containing the gene for the Merozoite Surface Protein-1 as encoding a major target of SSPI. A similar finding was also obtained in a previous LGS study using a different genetic cross between clones AS-pyr1 and CB of P. c. chabaudi (Martinelli et al., 2005). Hence, the results of two independent studies strongly indicate that a single locus within the parasite genome contains a major target antigen, or antigens, of SSPI against P. c. chabaudi malaria. These results have particular relevance for research on SSPI in human malaria and the choice of candidate antigens for malaria vaccine development. LGS analysis of growth rate conducted upon a genetic cross between a fast-growing line, 17XYM, and a slow-growing line, 33XC, of Plasmodium yoelii yoelii has identified a ~ 1 megabase pair region on P. y. yoelii chromosome 13 as containing a major genetic determinant(s) of growth rate in these malaria parasites. This is consistent with the finding of the classical linkage analysis by Walliker et al., (1976), that growth rate in P. y. yoelii is mainly determined at a single genetic locus. Because the fast-growing line 17XYM arose spontaneously during infection with a mild strain of P. y. yoelii 17X, identification of parasites with a slow growth rate phenotype derived from the same genetic stock as 17XYM can be useful in determining genes underlying growth rate in these malaria parasites. It has been shown here that parasites of the P. y. yoelii lines 17X consist of two completely distinct genotypes. One is represented by the fast-growing line, 17XYM, and a slow-growing line of P. y. yoelii, 17XNIMR. The other is represented by another slow-growing line 17XA. Comparing the region of P. y. yoelii chromosome 13 under strong growth selection between the two congenic lines, 17XYM and 17XNIMR, could lead to the identification of the gene(s) controlling growth rate differences in these two parasite lines. Such findings could be relevant to the location of genetic determinants of growth rate in human malaria.
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Salas, Fernandez Paloma. "Synthesis and biological activity of chloroquine ferrocenyl conjugates for the treatment of malaria." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/43009.
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Abshire, James R. (James Robbins). "Development of novel chemical biology tools to probe malaria parasite physiology and aid in antimalarial drug discovery." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98921.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Biological Engineering, 2015.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references.
Malaria remains a major burden to global public health. Antimalarial drugs are a mainstay in efforts to control and eventually eradicate this disease. However, increasing drug resistance threatens to reverse recent gains in malaria control, making the discovery of new antimalarials critical. Antimalarial discovery is especially challenging due to the unique biology of malaria parasites, the scarcity of tools for identifying new drug targets, and the poorly understood mechanisms of action of existing antimalarials. Therefore, this work describes the development of two chemical biology tools to address unmet needs in antimalarial drug discovery. A particular challenge in antimalarial development is a shortage of validated parasite drug targets. Potent antimalarials with demonstrated clinical efficacy, like the aminoquinolines and artemisinins, represent a promising basis for rational drug development. Unfortunately, the molecular targets of these drugs have not been identified. While both are thought to interact with parasite heme, linking in vitro heme binding with drug potency remains challenging because labile heme is difficult to quantify in live cells. This work presents a novel genetically-encoded heme biosensor and describes its application to quantify labile heme in live malaria parasites and test mechanisms of antimalarial action. Another challenge is posed by the widespread malaria parasite Plasmodium vivax, which, unlike P. falciparum, cannot be propagated in vitro, hindering research into parasite biology and drug target identification. P. vivax preferentially invades reticulocytes, which are impractical to obtain in continuous supply. The basis for this invasion tropism remains incompletely understood, mainly because current tools cannot directly link molecular binding events to invasion outcomes. This work presents novel methods for immobilizing synthetic receptors on the red blood cell surface. These receptors are used in proof-of-concept experiments to investigate requirements for efficient invasion via a well-characterized P. falciparum invasion pathway, suggesting this method can be used to elucidate molecular mechanisms underlying parasite invasion tropisms. Future receptor designs could promote the invasion of P. vivax into mature red blood cells and potentially facilitate practical in vitro culture. Taken together, these tools present new opportunities for drug discovery to aid efforts in malaria control and eventual eradication.
by James R. Abshire.
Ph. D.
11
Prior, Kimberley Faith. "The evolutionary ecology of circadian rhythms in malaria parasites." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/29562.
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Biological rhythms are thought to have evolved to enable organisms to organise their activities according to the Earth’s predictable cycles, but quantifying the fitness advantages of rhythms is challenging and data revealing their costs and benefits are scarce. More difficult still is explaining why parasites that exclusively live within the bodies of other organisms have biological rhythms. Rhythms exist in the development and traits of parasites, in host immune responses, and in disease susceptibility. This raises the possibility that timing matters for how hosts and parasites interact and, consequently, for the severity and transmission of diseases. Despite their obvious importance in other fields, circadian rhythms are a neglected aspect of ecology and evolutionary biology. The ambitions of this thesis are to integrate chronobiology, parasitology and evolutionary theory with mathematical models to obtain a greater understanding about how and suggest why malaria parasites have rhythms as well as the effect of infection on host rhythms. First, I identify how malaria parasites lose their developmental rhythms in culture, when they lack any potential time cues from the host. Next, I characterise parasite rhythms inside the mammalian host in terms of synchrony and timing and demonstrate there is genotype by environment interactions for characteristics of parasite rhythms. Then, I investigate the effect that parasite infection has on host rhythms and show there is variation between parasite genotypes in their effect on host locomotor activity and body temperature rhythms during infections. Finally, I explore which host rhythms may be driving parasite synchrony and timing and demonstrate the importance of peripheral host rhythms for the timing of malaria parasite developmental rhythms. The data presented here provides novel and important information on the role of rhythms during disease and opens up a new arena for studying host-parasite coevolution.
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Sanz, Sender Silvia. "Synthesis and biological function of fucose in Plasmodium falciparum." Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/587108.
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Malaria is a parasitic disease caused by Plasmodium parasites and it is transmitted by female Anopheles mosquito. P. falciparum has a complex life cycle that includes important stages in two different hosts: a mosquito and a human. The transmission between the human and the mosquito host also involves the transition between asexual and sexual forms of the parasites.
Glycobiology includes the study of carbohydrate metabolism and glycoconjugate (glycoprotein and glycolipid) structures. Protozoan parasites synthesize different glycoconjugates for protection and to respond to changes in the environment. Glycoconjugates coat the parasite surface with carbohydrates generally different from the host ones. They are crucial for parasite virulence and survival. Until very recently the only glycan structures described in P. falciparum were the GPI-anchors, however other glycan structures have been found in the past few years as the N-glycans or C-mannosylation. The glycome consists in the complete set of glycosylations that an organism or a cell produces at a certain time point, therefore the description of the parasite glycome may help to understand better the host- pathogen interactions in parasitic diseases. Sugar nucleotides are activated forms of monosaccharides that are the donors of glycosyltransferases to form glyconjugates. They can be synthesized by a de novo pathway that consists in the bioconversion of an existing sugar or sugar nucleotide; or by a salvage pathway that involves an activation and a further pyrophosphorylation. The identification and quantification of the sugar nucleotides present in malaria parasites may help to describe its glycosylation profile.
The first paper presented in the thesis describes the identification and quantification of the sugar nucleotides present in the parasite, among which we found: UDP-Glc, UDP-Gal, UDP-GlcNAc, GDP-Man and GDP-Fuc. We also investigated the salvage pathways present in the parasite but we couldn’t elucidate the presence of a fucose salvage pathway. Plasmodium parasites conserve homolog genes for the de novo biosynthetic pathway of GDP-Fuc: GMD and FS. We were able to prove the in vitro activity of GMD and FS enzymes and to show that both enzymes are required for the synthesis of fucose. GMD and FS are expressed along the intraerythrocytic life cycle and both enzymes localize in the cytoplasm of the parasite, as well as other parasite enzymes related with carbohydrate metabolism. The expression of a putative O-fucosyltransferase (PoFUT2) present in the parasite genome, together with the uptake of GDP-Fuc by parasite extracts suggested the presence of a fucose containing glycan.
In the second paper, we characterized the enzymes responsible for the synthesis of GDP-Fuc, GMD and FS. We disrupted both genes in the parasite and analyzed the sugar nucleotide content present in the parasite. After GMD and FS disruption, GDP-Fuc was still detected in the parasite and no evidence of salvage mechanism was found. We described indirect evidence of a fucose containing glycan that was abrogated after the disruption of GMD.
The last work here presented (not yet published) tries to characterize the enzyme that is probably responsible for the transfer of fucose to the glycoconjugate. We disrupted, by double crossover recombination, PoFUT2 gene in the human and in the rodent malaria parasite. The disruption of PoFUT2 does not have any significant effect for the viability and growth of the parasite along the parasite cycle in the human and in the mosquito host.
These works open the door to new research lines to find an alternative pathway for obtaining fucose or GDP-Fuc. Obtaining evidence of the glycosylation state of PoFUT2 mutants and the characterization of other possible glycosylation reaction present in the parasite are other research topics to investigate.La malaria está causada por el parásito Plasmodium y se transmite mediante hembras del mosquito Anopheles. La glicobiología es el estudio de los procesos relacionados con los carbohidratos y las estructuras glicoconjugadas que forman. Los parásitos sintetizan glicoconjugados o proteínas de unión a glicanos, y muchas veces se encargan de mediar las interacciones huésped-patógeno. Los azúcares nucleótidos son formas activadas de monosacáridos que son usados por glicosiltransferasas para formar glicoconjugados. La identificación y cuantificación de estos azúcares nucleótidos en el parásito de la malaria puede contribuir a la definición de su perfil de glicosilación. El primer trabajo presentado en la tesis permitió identificar los azúcares nucleótidos presentes en el parásito, así como la posible presencia de un glicoconjugado que contenga fucosa, sintetizado a partir de la actividad O-fucosiltransferasa de una proteína homóloga anotada en el genoma del parásito, PoFUT2. El siguiente trabajo permitió caracterizar las enzimas implicadas en la síntesis de la GDP-fucosa, GMD y FS. Este artículo nos permitió mostrar evidencias indirectas de la presencia del glicococonjugado que contiene fucosa. A partir de la disrupción de los genes de biosíntesis descubrimos que el contenido de GDP-fucosa en parásitos mutantes no variaba con respecto a los parásitos salvajes. Sin embargo, la síntesis del gliconjugado sí que se reducía. El tercer trabajo (sin publicar) se centra en la caracterización de la enzima encargada de transferir la fucosa al glicoconjugado. La disrupción de PoFUT2 no parece tener ningún efecto en la viabilidad y crecimiento del parásito a lo largo del ciclo de éste en el humano y en el mosquito. Estos trabajos abren la puerta a nuevas investigaciones para descubrir una vía alternativa de obtención de GDP-Fucosa. La obtención de evidencias del estado de glicosilación de los mutantes de PoFUT2 y la caracterización de otras posibles glicosilaciones son otros temas a investigar.
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Krein, Ze-ev. "Utilisation of efficient reactions to combine moeities exhibiting biological activity to produce novel anti-infectives against HIV and malaria." Master's thesis, University of Cape Town, 2007. http://hdl.handle.net/11427/6320.
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Includes abstract.Includes bibliographical references (leaves 151-155).
Chloroquine (CQ) was previously identified as a potential anti-HIV agent and reported to inhibit the production of infectious viral particles at concentrations which are non toxic to human cultured cells. It is speculated that this activity is associated with the decreased production of the heavily glycosylated epitope 2G 12 which is found on the gp120 glycoprotein surface. The hypothesized mechanism involves CQ acting on a range of cellular targets. This work identifies CQ as a lead compound for the discovery of potentially inexpensive drugs and its ability to target cellular enzymes as opposed to viral enzymes may endow the compound with the capacity to oppose resistance. This previous work was the basis of this project and prompted a further investigation into whether the quinoline scaffold is the principal cause of CQ's activity and whether other rationally designed compounds which contain this scaffold would be able to maintain similar or even greater anti-HIV activity. In an attempt to achieve greater activity, the dual drug approach was utilized.
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Mirghani, Rajaa A. "Quinine metabolism in man : emphasis on the 3-hydroxylation as a biomarker reaction for the activity of CYP3A4 /." Stockholm : [Karolinska institutets bibl.], 2002. http://diss.kib.ki.se/2002/91-7349-174-8.
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Amorim, Rodrigo César das Neves. "Contribuições para o conhecimento da composição química e atividade biológica de infusões, extratos e quassinóides obtidos de Picrolemma sprucei Hook.f. (Simaroubaceae)." Universidade Federal do Amazonas, 2009. http://tede.ufam.edu.br/handle/tede/3088.
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Previous issue date: 2009-09-11Conselho Nacional de Desenvolvimento Científico e Tecnológico
Isobrucein B (2) and neosergeolide (5) are quassinoids which are obtained from Picrolemma sprucei. These compounds have proven in vitro antitumor, antimalarial, anthelminthic, cytotoxic, insecticide and leishmanicidal activities. Herein, in vitro techniques were used to investigate a range of biological activities of 2 and 5 and known semi-synthetic derivative 1,12-diacetylisobrucein B (21) and 12-acetylneosergeolide (22). These compounds were evaluated for general toxicity toward the brine shrimp species Artemia franciscana, cytotoxicity toward human tumour cells, larvicidal activity toward the dengue fever mosquito vector Aedes aegypti and antimalarial activity against the human malaria parasite Plasmodium falciparum. 2 and 5 exhibited the greatest antimalarial activity against multidrug-resistant P. falciparum K1 strain. 2 and 5 (LC50 = 3.2-4.4 mg/L) displayed greater lethality than derivative 22 (LC50 = 75.0 mg/L) toward A. aegypti larvae, while derivative 21 was inactive. Biological assays were also performed with extracts and fractions obtained from P. sprucei fruit. A TLC densitometry method was developed to mensurate the quassinoids content in fruits extracts and fractions. This analysis determinate that only chloroform fractions presents significative content of 2 and 5 and this data is related to the biological activities. Infusions of the stems of P. sprucei are used in the Amazon region as antimalarials. They contain 2 and 5. An LC-(+)-ESI-MS/MS method was developed and applied to the determination of 2 and 5 in P. sprucei infusions. The concentrations of 2 and 5 in the stem infusion were found to be 60.1 and 774 μg L-1, respectively
Isobruceína B (2) e a neosergeolida (5) são quassinóides obtidos de Picrolemma sprucei. Essas substâncias possuem atividade antitumoral, antimalárica, anti-helmíntica, citotóxica, inseticida e leishmanicida in vitro já comprovadas. Neste trabalho, técnicas in vitro foram utilizadas para investigar uma variedade de atividades biológicas de 2 e 5 e dos derivados semi-sintéticos 1,12-diacetilisobruceína B (21) e 12-acetilneosergeolida (22). Essas substâncias foram avaliadas quanto à sua toxicidade geral frente a larvas do microcrustáceo Artemia franciscana, citotoxicidade frente a células tumorais humanas em colaboração com o laboratório de Oncologia da UFC, sob coordenação da Profa. Cláudia Pessoa, atividade larvicida frente a larvas do mosquito vetor da dengue Aedes aegypti e atividade antimalárica frente ao parasita causador da malária humana Plasmodium falciparum. 2 e 5 exibiram elevada atividade antimalárica frente à cepa multiresistente de P. falciparum K1 (CI50 1,0-4,0 ng/mL). 2 e 5 (CL50 3,2-4,4 mg/L) apresentaram letalidade bem mais elevada do que o derivado 22 frente a larvas de A. aegypti, ao passo que o derivado 21 se mostrou inativo. Ensaios biológicos também foram realizados com extratos e frações obtidos de frutos de P. sprucei. Um método baseado em CCD-densitometria foi desenvolvido para mensurar o teor de quassinóides nos frutos e frações destes frutos. Essas análises determinaram que apenas as frações obtidas em clorofórmio apresentam teores significativos de 2 e 5 e esses teores estão relacionados às atividades biológicas. Infusões dos caules de P. sprucei são utilizadas na Amazônia . Um método baseado em LC-(+)-ESI-MS/MS foi desenvolvido e aplicado para determinar o teor de 2 e 5 em infusões de P. sprucei. As concentrações de 2 e 5 nas infusões de caules são de 60,1 e 774 μg L-1, respectivamente
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Matos, Carolina Thieleke da Silva Macedo. "Interaction of malaria parasites with host late endocytic and autophagic pathways is essential for Plasmodium liver stage development." Doctoral thesis, Faculdade de Ciências Médicas, 2013. http://hdl.handle.net/10362/12157.
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RESUMO: A Malária é causada por parasitas do género Plasmodium, sendo a doença parasitária mais fatal para o ser humano. Apesar de, durante o século passado, o desenvolvimento económico e a implementação de diversas medidas de controlo, tenham permitido erradicar a doença em muitos países, a Malária continua a ser um problema de saúde grave, em particular nos países em desenvolvimento.
A Malária é transmitida através da picada de uma fêmea de mosquito do género Anopheles. Durante a picada, os esporozoítos são injetados na pele do hospedeiro, seguindo-se a fase hepática e obrigatória do ciclo de vida. No fígado, os esporozoítos infetam os hepatócitos onde se replicam, dentro de um vacúolo parasitário (VP) e de uma forma imunitária silenciosa, em centenas de merozoitos. Estas novas formas do parasita são as responsáveis por infetar os eritrócitos, iniciando a fase sanguínea da doença, onde se os primeiros sintomas se manifestam, tais como a característica febre cíclica. A fase hepática da doença é a menos estudada e compreendida. Mais ainda, as interações entre o VP e os organelos da células hospedeira estão ainda pouco caracterizados. Assim, neste estudo, as interações entre os organelos endocíticos e autofágicos da célula hospedeira e o VP foram dissecados, observando-se que os anfisomas, que são organelos resultantes da intersecção do dois processos de tráfego intracelular, interagem com o parasita. Descobrimos que a autofagia tem também uma importante função imunitária durante a fase hepática inicial, ao passo, que durante o desenvolvimento do parasita, já numa fase mais tardia, o parasita depende da interação com os endossomas tardios e anfisomas para crescer. Vesiculas de BSA, EGF e LC3, foram, também, observadas dentro do VP, sugerindo que os parasitas são capazes de internalizar material endocítico e autofágico do hospedeiro. Mais ainda, mostramos que esta interação depende da cinase PIKfyve, responsável pela conversão do fosfoinositidio-3-fosfato no fosfoinositidio-3,5-bifosfato, uma vez que inibindo esta cinase o parasita não é capaz de crescer normalmente. Finalmente, mostramos que a proteína TRPML1, uma proteína efetora do fosfoinositidio-3,5-bifosfato, e envolvida no processo de fusão das membranas dos organelos endocíticos e autofágicos, também é necessária para o crescimento do parasita. Desta forma, o nosso estudo sugere que a membrana do VP funde com vesiculas endocíticas e autofágicas tardias, de uma forma dependente do fositidio-3,5-bifosfato e do seu effetor TRPML1, permitindo a troca de material com a célula hospedeira.
Concluindo, os nossos resultados evidenciam que o processo autofágico que ocorre na célula hospedeira tem um papel duplo durante a fase hepática da malaria. Enquanto numa fase inicial os hepatócitos usam o processo autofágico como forma de defesa contra o parasita, já durante a fase de replicação o VP funde com vesiculas autofágicas e endocíticas de forma a obter os nutrientes necessários ao seu desenvolvimento.--------- ABSTRACT: Malaria, which is caused by parasites of the genus Plasmodium, is the most deadly parasitic infection in humans. Although economic development and the implementation of control measures during the last century have erradicated the disease from many areas of the world, it remains a serious human health issue, particularly in developing countries.
Malaria is transmitted by female mosquitoes of the genus Anopheles. During the mosquito blood meal, Plasmodium spp. sporozoites are injected into the skin dermis of the vertebrate host, followed by an obligatory liver stage. Upon entering the liver, Plasmodium parasites infect hepatocytes and silently replicate inside a host cell-derived parasitophorous vacuole (PV) into thousands of merozoites. These new parasite forms can infect red blood cells initiating the the blood stage of the disease which shows the characteristic febrile malaria episodes. The liver stage is the least characterized step of the malaria infection. Moreover, the interactions between the Plasmodium spp. PV and the host cell trafficking pathways are poorly understood. We dissected the interaction between Plasmodium parasites and the host cell endocytic and autophagic pathways and we found that both pathways intersect and interconnect in the close vicinity of the parasite PV, where amphisomes are formed and accumulate. Interestingly, we observed a clearance function for autophagy in hepatocytes infected with Plasmodium berghei parasites at early infection times, whereas during late liver stage development late endosomes and amphisomes are required for parasite growth. Moreover, we found the presence of internalized BSA, EGF and LC3 inside parasite vacuoles, suggesting that the parasites uptake endocytic and autophagic cargo. Furthermore, we showed that the interaction between the PV and host traffic pathways is dependent on the kinase PIKfyve, which converts the phosphoinositide PI(3)P into PI(3,5)P2, since PIKfyve inhibition caused a reduction in parasite growth. Finally, we showed that the PI(3,5)P2 effector protein TRPML1, which is involved in late endocytic and autophagic membrane fusion, is also required for parasite development. Thus, our studies suggest that the parasite parasitophorous vacuole membrane (PVM) is able to fuse with late endocytic and autophagic vesicles in a PI(3,5)P2- and TRPML1-dependent manner, allowing the exchange of material between the host cell and the parasites, necessary for the rapid development of the latter that is seen during the liver stage of infection. In conclusion, we present evidence supporting a specific and essential dual role of host autophagy during the course of Plasmodium liver infection. Whereas in the initial hours of infection the host cell uses autophagy as a cell survival mechanism to fight the infection, during the replicative phase the PV fuses with host autophagic and endocytic vesicles to obtain nutrients required for parasite growth.
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Cutler, David John. "The use of oxyallyl cations in the synthesis of biologically interesting molecules." Thesis, University of Reading, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.484196.
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Ahmad, Amirrudin Bin. "Biological diversity of freshwater fishes in small streams in peninsular Malaysia." Thesis, University of St Andrews, 2012. http://hdl.handle.net/10023/3144.
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Peninsular Malaysia has a diverse flora and fauna, much of which is yet to be documented. The freshwater fishes are one important group that have received little attention. Accordingly, the overarching goal of my study is to investigate the pattern of species richness and analyse the community composition and assemblage structure of fishes in the small streams in Peninsular Malaysia. Small stream habitats appeared to be particularly important repositories of fish biodiversity in this region thus obtaining a reliable census of species occurring in such habitats is critical for conservation and management of biodiversity. Although samplings were far from completed, these habitats support a great variety of species with more than 100 species were recorded from fifty streams sampled in this study. A few are extremely rare with restricted distribution and can thus be considered important in biodiversity conservation of the Peninsular Malaysian ichthyofauna. Human-influenced modification of lowland, headwater stream habitats in Peninsular Malaysia is common and often exemplified by the creation of pools in stretches of rapids and riffles. However, it was not possible to separate pristine and disturbed sites which contained almost identical for species diversity. These findings suggest that local habitat modification does not necessarily cause a decrease in freshwater fish diversity, with only minor negative consequences for other community variables recorded in this study, and therefore raise interesting issues regarding conservation. That said it remains premature to conclude that small stream fishes are insensitive to disturbance and thus their potential utility as bioindicators of disturbance-influenced community changes remain to be confirmed. The maintenance practises being applied to small streams modified for recreational usage were not imposing detectable negative consequences, at least across the sites sampled in this study. The rich diversity of tropical stream environments is the result of both within-habitat (alpha) diversity and between-habitat (beta) diversity. The results showed that there was substantial beta diversity particularly amongst sites that are geographically separated from one another. On the contrary, the lowest beta diversity values were portrayed by contiguous sites. Many fishes exhibited discontinuous patterns of distribution and were considered to be rare while only a handful were widely distributed and abundant. Ordination based on the relative resemblance of fish communities to one another support the existence of two distinct ichthyogeographic divisions in Peninsular Malaysia. It was possible to assign the species recorded to all seven of Rabinowitz's categories of rarity, with at least 10 restricted to a single stream and locally scarce, although not all of these could be described as hyper-endemic. It is recommended that a sizeable augmentation of the existing protected areas is needed to safeguard Malaysia's exceptionally diverse stream-dwelling fauna of which fishes are simply the most well-known inhabitants. Conservation managers should therefore place particular emphasis on small streams since localities in close proximity to one another can exhibit surprisingly high beta diversity, meaning that partial or small-scale habitat protection may prove insufficient.
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Ramli, Mohd Fadzil Shuhaimi bin. "Impacts of coastal land reclamation on the fisheries of Mukim Lekir, Malaysia." Thesis, University of Hull, 2005. http://hydra.hull.ac.uk/resources/hull:11158.
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In 1997, land reclamation works began in the coastal area of Mukim Lekir. Ultimately, an area of 8,094 ha was planned to be reclaimed along Lekir's coastline, but to date; only Phase 1 of the project has been completed. The Phase 1 project of 405 ha, created a man-made island for the location of a 2,100MW, coal-fired power plant; a first of its kind in Malaysia. Although the reclaimed land was only 5 % of the total intended area, its impacts on the livelihoods of the coastal communities, especially fishers, were serious and nearby mangroves were degraded. The effect of this intervention was observed to be long-term, contrary to the claims made by the project proponents. Fishers and other coastal inhabitants incurred monetary losses, which were neglected by the project proponents, who also failed over the issue of compensation. This study attempts to establish evidence that the project caused hardship to coastal population, especially fishers who depended on fishery resources that were found to decline after the commencement of the project. It began by assessing the status of fish stock, analysing its catch-rates trend and comparing them with resource status before the project. A socio-economic survey by face-to-face questionnaires interview was carried out on the population to obtain information on how the project had affected their livelihoods in terms of incomes, job opportunity, fishing activities, pollution, etc. The research design intended to prove that environmental degradation was caused by the project by comparing the status of resources before and after the intervention. On the issue of compensation, losses were valued in monetary terms, so that it was easily understood and appreciated. The purpose of valuing damages was to allow affected persons to claim compensation in monetary terms. This study emphasized losses through mangrove degradation and losses as result of fishery resources declining. In addition, losses incurred by cockle farmers and the government were also gauged. For mangrove degradation, a survey using the Contingent Valuation Method was carried out to estimate people's willingness to pay (WTP) on a hypothetical project aiming to protect the mangroves. The amount they were WTP was the benefit loss of not being able to use the mangroves. Other losses valuation was straightforward since it involved marketable or tangible goods. The standing of fishers and other affected communities claiming compensation in the court of laws was discussed. Fish stock assessment done in 2002 and 2003 in the Lekir waters indicated that the resource showed a declining trend since 1996. Commercial fish declined at a greater rate in sub-area A, which was closer to the impacted area, than in sub-area B; located further away. Subarea A was also found to loose its potential as breeding and nursery grounds, since fewer juveniles and fingerlings were caught compared with the 1996 survey. The decline in the fisheries indicative from the surveys was verified by fishers who complained of reduced catches and incomes. In the socio-economic survey, fishers were found not to benefit from the development since the project did not provide them with employment opportunity or generate other kinds of income-induced opportunity. The degradation ofthe mangroves and the fishery were proven to be caused by the present of the project since the control areas, in the absence of perturbation did not show similar characteristic as the impacted areas. The benefit loss of mangrove use was estimated at RM 81,959/year whereas other society losses were RM 118,333,321 in the six years since the perturbation. If fishers were to claim compensation, they have to prove that their losses were above and over the general public and preferably under the rule of Rylands V Fletcher. Other segments of the society may need government intervention since they were claiming pure economic loss, which is unrecoverable in the Common Laws. This study does not advocate monetary compensation to each affected individual but prefers long-term aid to regenerate rural livelihoods. Economic projects are proposed involving active participation of the community. Further researches are also suggested to improve data collection, developing comprehensive stock assessment and improving EIA procedures.
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Motta, Luiz Frederico 1971. "Estudo teorico das relações estrutura-atividade biologica de uma serie de derivados de chalcona (1,3-difenil-2propen-1-ona) como agentes anti-plasmodium falciparum (agentes antimalaricos)." [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249727.
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Orientador : Yuji TakahataDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica
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Mestrado
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Grimm, Amandine. "Mitochondria, neurosteroids and biological rhythms : implications in health and disease states." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAJ002/document.
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Les mitochondries jouent un rôle primordial dans la survie et la mort cellulaire car elles gouvernent à la fois le métabolisme énergétique et les voies apoptotiques. Un dysfonctionnement mitochondrial dans les neurones peut donc conduire à la neurodégénérescence ou à une neuropathologie. Notre objectif a été d'étudier la régulation de la fonction mitochondriale, en particulier la bioénergétique, pour contribuer à l'amélioration des connaissances actuelles sur les mitochondries. Nos résultats montrent que: i) les neurostéroïdes améliorent la bioénergétique mitochondriale en stimulant la respiration cellulaire en condition normale; ii) les neurostéroïdes réduisent les déficits bioénergétiques observés dans la maladie d'Alzheimer; iii) l'horloge circadienne développe une régulation réciproque avec la bioénergétique et la dynamique mitochondriales. Les résultats de cette thèse ouvrent des perspectives intéressantes pour l'élaboration de stratégies régulatrices de l'homéostasie métabolique chez le sujet sain et chez le patient atteint d'une pathologie due à un dysfonctionnement mitochondrial et/ou une altération des rythmes biologiquesMitochondria play a paramount role in cell survival and death because they are orchestrating both energy metabolism and apoptotic pathways, while impaired mitochondrial function leads inevitably to disease, especially neurodegeneration. The purpose of the present thesis was therefore to deepen our understanding of the regulation of mitochondrial function, with a focus on mitochondrial bioenergetics and dynamics. Our key findings were that: i) neurosteroids represent promising molecules which are able to increase mitochondrial bioenergetics via enhancement of mitochondrial respiration in healthy condition; ii) neurosteroids are able to alleviate Alzheimer’s disease-related bioenergetic deficits; iii) the circadian clock is able to regulate mitochondrial bioenergetics and dynamics, and vice versa. Collectively, our results contribute to a better understanding of how mitochondria function, and could have multiple implications with regard to the regulation of metabolic homeostasis in health and disease states associated with mitochondrial impairments and/or circadian disruption
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Duarte, Sofia Inês Leal. "Action of new porphyrin conjugates with potential anti-malaria activity on membranes." Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/17308.
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Mestrado em BioquímicaA malária é uma doença negligenciada que afeta mais de 100 países e ameaça metade da população mundial. Esta doença é transmitida pela picada do mosquito Anopheles, causando a infeção dos glóbulos vermelhos. O parasita da malária, Plasmodium, pertence à família dos protozoários, sendo por isso um organismo eucariota. Durante a invasão dos eritrócitos, o parasita degrada hemoglobina para obter nutrientes, contudo é libertado o grupo heme que é tóxico para a membrana do mesmo. Para ultrapassar os efeitos tóxicos do grupo heme, o parasita converteo num pigmento insolúvel, a hemozoina. Análogos sintéticos de porfirinas podem ser usados como alternativa a combater a malária, uma vez que são estruturalmente idênticos ao grupo heme. Assim, o presente trabalho teve como objetivo a síntese de novos conjugados porfirínicos com fármacos já usados na prevenção da malária. Para isso usou-se a 5,10,15,20-tetrakis (pentafluorfenil) porfirina (TF5PP) (composto 1) como porfirina inicial e sintetizaram-se novos derivados porfirínicos formados por conjugação da porfirina com três fármacos diferentes já usados na prevenção da malária: a primaquina (composto 3), a mefloquina (composto 5) e o artesunato (composto 9). A reação de conjugação para os dois primeiros compostos teve como base uma reação de substituição nucleofílica. A síntese do último conjugado não foi alcançada com sucesso. Posteriormente, foram sintetizados os complexos de Fe(III) dos três compostos obtidos: 1, 3 e 5. Para avaliar a possível utilização destes conjugados monitorizou-se a peroxidação em lipossomas constituídos por dois fosfolípidos, 1,2-dimeristoil-sn-glicero-3- fosfocolina (dMPC) (lípido saturado) e a 1-palmitoil-2-linoleoil-3-fosfocolina (PLPC) (lípido insaturado). Os lipossomas foram incubados com os diferentes compostos, na presença e na ausência de H2O2, e a reação foi controlada por espectrometria de massa em modo positivo (ESI-MS). Através da razão [dMPC+H]+/[PLPC+H]+ foi possível avaliar a extensão da reação. Apenas os complexos de ferro dos compostos 1, 3 e 5 (respetivamente os compostos 2, 4 e 6) mostraram ter capacidade para oxidar a PLPC e na presença do composto 2 houve um maior aumento da razão [dMPC+H]+/[PLPC+H]+. Verificou-se que este composto na ausência de H2O2 é mais eficaz que os compostos 4 e 6, tanto na presença como ausência de peróxido de hidrogénio. Os produtos de oxidação obtidos na presença dos diferentes complexos mostraram a presença de um, dois e três átomos de oxigénio e a sua formação poderá ter sido mediada por espécies oxo de alta valência ou via peroxidação lipídica induzida por radicais.
Malaria is a neglected disease that affects more than 100 countries and threatens half of the world population. The disease is transmitted through the bite of an infected female mosquito Anopheles, causing infection of erythrocytes. The malaria parasite, Plasmodium, belongs to the family of protozoa, and so is a eukaryotic organism. During the invasion of the erythrocytes, the parasite degrades hemoglobin to obtain nutrients, yet is released the heme group that is toxic to parasite membrane. To overcome the toxic effects parasite converts free heme into an insoluble pigment called hemozoin. Synthetic analogs of porphyrins can be used as alternative to combat malaria, since they are structurally identical to the heme group. The present study aimed to synthetize new porphyrin conjugates with drugs already used in the prevention of malaria. For that, it was used 5,10,15,20-tetrakis (pentafluorophenyl) porphyrin (TF5PP) (compound 1) as a starting porphyrin and it were synthetized new porphyrin derivatives formed by conjugation with three different drug, primaquine (compound 3), mefloquine (compound 5) and artesunate (compound 9). The reaction for the first two compounds was based on a nucleophilic substitution reaction. The synthesis of compound 9 was not achieved. Subsequently, the Fe(III) complexes of the three compounds: 1, 3 and 5 were synthetized. To evaluate the possible use of these conjugates, lipid peroxidation was evaluated in liposomes constituted with two phospholipids: 1,2-dimyristoyl-sn-glycero- 3-phosphocholine (saturated lipid) and palmitoyl-lineloylphosphatidylcholine (unsaturated lipid). Liposomes were incubated with the different compounds in the presence and in the absence of H2O2 and the reaction was monitored by mass spectrometry in positive mode (ESI-MS). Through the ratio [dMPC+H]+/[PLPC+H]+ it was possible to evaluate the extent of reaction. Only the iron complexes (compounds 2, 4 and 6) showed to have the ability to oxidize PLPC and in the presence of compound 2 there was a greater increase in the ratio [dMPC+H]+/[PLPC+H]+. It was verified that this compound in the absence of H2O2 has greater oxidation than compounds 4 and 6, both in the presence or absence of hydrogen peroxide. The oxidation products obtained in the presence of the different complexes showed the presence of one, two and three oxygen atoms and their formation may have been mediated by high valent oxo species or through radical-induced lipid peroxidation.
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Laureti, Silvio <1966>. "Il trattamento combinato della malattia perianale di Crohn: chirurgia e farmaci biologici." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/710/.
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Manan, Mohamed Mansor. "Influence of ethnicity in optimizing antiepileptic drug dosing : a comparison of Malay, Chinese and Indian populations in Malaysia." Thesis, University of Nottingham, 1999. http://eprints.nottingham.ac.uk/12787/.
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Reports of inter-ethnic differences in metabolism for phenytoin and carbamazepineh have raised questions concerning the importance of monitoring serum levels to the standardised population therapeutic concentrations. Although the pharmacokinetics of phenytoin, carbamazepine, valproic acid and phenobarbitone displayed both intra and inter-individual variations, the influence of ethnicity is still unclear. This thesis has thus set its objectives of investigating the impact of ethnicity on the efficacy of these therapeutic ranges and pharmacokinetics of these drugs. A total 1554 serum concentrations were randomly selected by a set of criteria from 470 Malays, 423 Chinese and 322 Indian of adult and paediatric patients. The Mantel-Haenzel method was used to estimate for inter-ethnic differences in response to the defined therapeutic ranges. The influence of ethnicity on pharmacokinetics was examined by the test of heterogeneity of the slopes estimates in the linear relationship of either serum concentration or clearance to dose. Coefficient of variation on the ratios of the above relationships was used to measure for inter individual variation. The results showed a highly variable response to treatment within the defined therapeutic ranges. Therapeutic response is not dependent on ethnicity and age although the latter was determined on carbamazepine and valproic acid treated patients only. The pharmacokinetics of carbamazepine, valproic acid and phenobarbitone showed high inter-individual variations and were unaffected by weight, age or ethnicity. Similar high inter-individual variation for phenytoin pharmacokinetic parameters (Km and Vmax) were observed. However, Km and Vmax(mg/day) of adult Chinese patients were significantly lower than Malay or Indian patients. The relationship between Km and Vmax and age or weight were insignificant. These findings demonstrate that Malaysian patients only differed in handling phenytoin therapy and support the use of ethnic specific phenytoin pharmacokinetic parameters during therapy.
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SIMÕES, Maria Luísa. "Hemozoin as an immune stimulant of the mosquito Anopheles gambiae response against the malaria parasite." Doctoral thesis, Instituto de Higiene e Medicina Tropical, 2014. http://hdl.handle.net/10362/19197.
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Hemozoína, um metabolito produzido por Plasmodium spp., tem surgido como um potente estimulador, activando o sistema imunitário do hospedeiro e levando à produção de citocinas e quimiocinas em tecidos de mamíferos. Neste estudo, desvendamos o papel deste subproduto do parasita como estimulador da imunidade de Anopheles gambiae em
resposta à infecção por Plasmodium berghei. A malária é uma doença infecciosa de distribuição mundial, causada por parasitas do género Plasmodium e transmitida pelas fêmeas de mosquitos do género Anopheles. A resposta imunitária do mosquito vector da malária contra o parasita envolve várias vias metabólicas que não se encontram ainda bem caracterizadas. Resultados laboratoriais revelaram que a hemozoína activa a expressão de
vários genes da imunidade, incluindo péptidos anti-microbianos e factores anti-Plasmodium. Destaca-se a indução, após estimulação com hemozoína, da forma larga (REL2-F) do factor de transcrição REL2, da via Immune deficiency (Imd). Estes resultados foram confirmados pela estimulação de tecidos e células de Anopheles gambiae com hemozoína sintética e silenciamento do gene que codifica REL2-F e do gene que codifica o seu regulador negativo Caspar. Neste trabalho, mostrou-se pela primeira vez o impacto do tratamento com hemozoína na infecção por Plasmodium: a hemozoína reduz eficientemente tanto a taxa como a intensidade da infecção no mosquito. Propomos, assim, que a hemozoína estimula a imunidade inata de Anopheles, activando a expressão de genes efectores que tornam o mosquito mais resistente ao Plasmodium, e que esta activação é mediada por REL2.
Após identificação de um conjunto de genes associados à imunidade induzidos pela hemozoína, e de acordo com as propriedades da via Imd/REL2 sugeridas pelos resultados obtidos, construímos uma linha de mosquitos Anopheles gambiae geneticamente modificados, através da sobreexpressão do gene anti-plasmódico FBN9 (fibrinogen
immunolectin 9), sob regulação de Vitellogenin 1, um promotor específico do corpo gordo.The Plasmodiummetabolite hemozoin has emerged as a potent immunostimulator, targeting the host immune system and activating the production of cytokines and chemokines in mammalian tissues. In this study, we disclose the role of this parasite’s byproduct as stimulator of Anopheles gambiaeimmunity to Plasmodium berghei. Malaria is a worldwide infectious disease caused by Plasmodiumparasites and transmitted by female Anophelesmosquitoes. The malaria vector mosquitoAnophelesimmune response to the parasite involves several pathways which are not yet well characterized. High throughput analyses revealed that hemozoin activates the expression of several immunity genes, including antimicrobial peptides (AMPs) and anti-Plasmodiumfactors. Importantly, we found that the Immune deficiency (Imd) pathway transcription factor REL2, in its full-length form REL2-F, was induced upon hemozoin treatment. These findings were confirmed by stimulation of Anopheles gambiaetissues and cells with synthetic hemozoin and silencing of REL2-F and its negative regulator Caspar. Notably, we have for the first time shown the impact of hemozoin treatment on Plasmodiuminfection, effectivelyreducing both rate and intensity of the infection. We propose that hemozoin boosts the innate immunity in Anopheles, activating key effector genes that turn the mosquito more resistantto Plasmodium, and this activation is REL2-mediated. Following identification ofa set of key immunity genes induced by hemozoin and encouraged by the properties of the Imd/REL2 pathway suggested by the obtained results,we have successfully engineered a genetically modified Anopheles gambiaeline, by overexpressionof FBN9(fibrinogen immunolectin 9) antiparasitic gene under regulation of the fat body-specific Vitellogenin 1 promoter.
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Tavares, Taizy Leda. "Estratégia genômica de vacinologia reversa para identificação de antígenos vacinais de Plasmodium vivax." Universidade Federal de Goiás, 2016. http://repositorio.bc.ufg.br/tede/handle/tede/6577.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Malaria is a parasitic disease caused by protozoa of the genus Plasmodium. In 2014 was registered 214 million new cases in worldwide with approximately 480,000 deaths. Brazil is responsible for about half of malaria cases that occur in America, where the main etiological agent is P. vivax. The absence of effective vaccines against malaria parasites is a serious obstacle to controlling the disease. In this context, this study aimed to identify peptides that may be candidates for the development of a vaccine against P. vivax through a immunoinformatics strategy called the Reverse Vaccinology (RV). Primarily, we track the P. falciparum proteome in search of proteins that presented predicted epitopes and were orthologs between species P. vivax and the species of malaria rodents, P. yoelli. The similarity between proteins and epitopes of the three species was quantified for excluding those that exhibited low similarity. Among this proteins, we sought in the literature which had been extensively studied and / or whether they had been vaccine candidates in previous research. For proteins that had been little studied or not evaluated, the prediction of B and T lymphocytes epitopes. Were thus identified 357 proteins of P. falciparum with predicted epitopes, among which 270 have orthologs in P. vivax and P. yoelli. Of these, fifty proteins were found to be highly similar between the three species under study, and 12 had little or no previous study. These 12 proteins were examined to Immunology Epitope Database program (IEDB) in order to implement the prediction of epitopes. Through a combinatorial analysis of the different immunoinformatics prediction methods, 7 proteins were selected as vaccine candidates, based on their function and / or location, such as export protein (EXP1), proteins expressed on the surface of the membrane (SERA) or transmembrane domain (MAEBL), or participate in processes essential for the survival of the parasite (CLAG). These proteins may be evaluated in the future biological assay constituents such as antigens in a vaccine against P. vivax parasite.
A malária é uma doença parasitária causada por protozoários do gênero Plasmodium. Em 2014 foram registrados 214 milhões de novos casos mundiais com aproximadamente 480.000 óbitos. O Brasil é responsável por cerca de metade dos casos de malária que ocorrem nas Américas, onde o principal agente etiológico é P. vivax. A ausência de vacinas eficazes contra parasitos de malária representa um sério obstáculo ao controle da doença. Nesse contexto, o presente trabalho identificou peptídeos que possam ser candidatos ao desenvolvimento de uma vacina contra P. vivax, através de uma estratégia de imunoinformática denominada de Vacinologia Reversa (VR). Primariamente, rastreamos o proteoma de P. falciparum em busca de proteínas que apresentassem epítopos preditos e fossem ortólogas entre as espécies P. vivax e a espécie de malária de roedores P. yoelli. A similaridade entre as proteínas e os epítopos das três espécies foi quantificada, visando excluir aquelas que exibissem baixa similaridade. Entre as proteínas restantes, buscamos na literatura quais já haviam sido extensivamente estudadas e/ou se já haviam sido candidatas vacinais em pesquisas anteriores. Para as proteínas que haviam sido pouco estudadas ou não avaliadas, foi realizada a predição de epítopos de linfócitos B e T. Foram assim identificadas 357 proteínas de P. falciparum com epítopos previstos, entre as quais, 270 possuíam ortólogos em P. vivax e P. yoelli. Destas, cinquenta proteínas revelaram ser altamente similares entre as três espécies em estudo, e 12 tinham poucos ou nenhum estudo anterior. Essas 12 proteínas foram submetidas ao programa Imunology Epitope Database (IEDB) no intuito de realizar a previsão de epítopos. Através de uma análise combinatória entre os diferentes métodos imunoinformáticos de previsão, 7 proteínas foram selecionadas como candidatas vacinais, com base em suas funções e/ou localização, como a proteína exportada (EXP1), proteínas expressas na superfície da membrana (SERA) ou com domínio transmembrana (MAEBL), ou ainda participam de processos essenciais para a sobrevivência do parasito (CLAG). Estas proteínas poderão ser avaliadas no futuro em ensaios biológicos como antígenos constituintes de uma vacina contra o parasito P. vivax.
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Msukwa, Amulike Victor. "The potential role of Lake Malawi National Park sanctuary areas for biological control of schistosomiasis and development of a sustainable fishery." Thesis, Rhodes University, 1998. http://hdl.handle.net/10962/d1005158.
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The potential role of sanctuary areas for biological control of Schistosomiasis and development of sustainable fisheries was investigated at Cape Maclear, Lake Malawi National Park (LMNP). There has been a recent increase in the incidence of schistosomiasis infection which is a threat to the local community as well as the tourism industry which is the major source of income to LMNP as well as Chembe Village. At the same place there is increasing fishing pressure due to growing human population and declining fish resource. The increase in the incidence of schistosomiasis transmission was attributed in part to over-fishing of the molluscivorous fish which are believed to control the vector snails for schistosomiasis. Four molluscivorous fish species, Trematocranus placodon; Trematocranus microstoma; Mylochromis sphaerodon and Mylochromis anaphyrmus were reported to account for more than 90% of the fishes (by numerical abundance) which feed on the gastropods above 15 metre depth. The gastropod numbers was reported to be highest at 1.5 to 4.5 metre depth. Of the four molluscivores, T. placodon was proposed as a biological control agent for schistosomiasis based upon the previous observations of its feeding habits in artificial conditions. Captive propagation of T. placodon for reintroduction at Cape Maclear in Lake Malawi has been proposed. The present study aimed at providing baseline data required to test the hypotheses that: 1) Over-fishing of the molluscivorous fish has resulted to the increased incidence of schistosomiasis at Cape Maclear. A sub hypothesis to this was that an extension of the LMNP can act as a sanctuary area for the biological control of schistosomiasis by protecting molluscivorous fish which could control schistosomiasis vector snails. 2) A park initially designed to protect the colourful rock dwelling fish and for promotion of tourism may not effectively protect the food fish. To test the first hypothesis, the biology and ecology of T. placodon were investigated with a view to evaluating the effect this species could have on the schistosomiasis vector snail population and hence the control of bilharzia in the lake. The proportions of various gastropod species at Cape Maclear was compared with those found in T. placodon guts. Comparisons of T. placodon abundance and demographic structure inside and outside LMNP were made. To test the second hypothesis, this study investigated the food fish species that use LMNP 100 m protected zone and some basic ecological factors to appreciate the extent to which the adjacent fishery might benefit from their use of the park waters. T. placodon numerical abundance (number of individuals per unit area) ranged from 5.7 to 40.5 /200 m² and it significantly (P< 0.05) varied between sampling sites. Otter Point and Mitande which are inside the park had the lowest abundance as compared to the other three sites; Nguli inside the park; Fisheries and Nchenga outside the park. Two sites in the park, Otter Point and Mitande, had a greater proportion of mature T. placodon individuals than all other sites. The abundance of T. placodon fluctuated significantly from month to month at Nchenga, Nguli and Fisheries (X² test, P<0.0001 for all the three sites) and insignificantly (P>0.05) at Otter Point and Mitande (X² test). T. placodon densities found in the present study corresponded to the peak density of 30 individuals / 200 m² reported in 1986 but did not correspond to that of 1.0 / 200 m² for 1994. There was no evidence to support the previous reports that T. placodon abundance had decreased tremendously from 1986. The reason suggested to account for the discrepancies of T. placodon abundance reported in the present study and other studies was inadequate sampling in the previous studies which did not take into account spatial and temporal variability in T. placodon abundance. The findings reported in this thesis show that there is no need for captive propagation of T. placodon to be reintroduced into the lake at Cape Maclear and that it may prove to be unsuccessful. However, since juvenile T. placodon dominated in abundance at the three sites along the major beach which is outside the park boundaries, it is suggested that the park boundaries be extended to this area so that T. placodon should be protected to allow individuals to grow to bigger size which would be more effective for gastropod control. T. placodon between 60 mm and 80 mm TL fed on benthic insects, phytoplankton and from detritus material. Individuals between 80 mm and 100 mm fed on a mixture of benthic insects, fish scales and small gastropods and at sizes greater than 100 mm individuals specialized feeding on gastropods. Gastropods of five genera were taken and they were: Melanoides , Bulinus, Gabiella, Lanistes and Bellamya. Of these genera Melanoides fonned the greatest part of T. placodon diet. Bulinus was the second most abundant genus but compared to Melanoides its proportion was very small. Of the three Bulinus species taken by T. placodon, B. globosus, is a confirmed vector for Schistosoma haematobium which is prevalent at Cape Maclear. This species was eaten in the least quantities. A comparison ofthe five gastropod proportions in T. placodon diet and in the habitats they occupy showed that Melanoides were taken in proportionately more quantities than Bulinus at most sites. These findings contrasted the previous reports that T. placodon preferred Bulinus to Melanoides. By applying the optimal foraging theory which predicts that an animal species searching for food will go for the type of prey with the highest profitability, it is concluded that the Bulinus cannot be eliminated completely by molluscivores because if their population size falls below a certain level, the fish will switch to other gastropod types. It is concluded that the increase in schistosomiasis may not be necessarily due to overfishing the molluscivorous fish but could be due to the fact that there has been an increase in the proportion of the B. globosus albeit in small numbers which are infected with schistosomiasis parasites. An integrated approach to schistosomiasis control at Cape Maclear comprising vector control, improved water supply, sanitation and health education is suggested since no method can be effective in isolation. Few food fish species were observed to use the park at various times, varying from one species to another with regards to duration, life history stages and abundance. Only a few fish species taken by the adjacent artisanal and commercial fisheries were represented among those observed in the park. This was attributed to the limited diversity of habitat types covered. Only small population size of some species visited the protected area and only part of the life cycle of some species were observed in the park. The use of the park area was seasonal for some species and the protected zone boundaries can be crossed more than once within a day because 100 m distance is just a few minutes swim by fish. Under such circumstances the park cannot function as an effective sanctuary for food fish. An increase of the park size may be a better option to effectively protect the food fish.
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Gentilini, Lorenzo <1979>. "Trattamento della malattia paranale complessa di Crohn: rescue therapy dopo fallimento dei farmaci biologici." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/6857/.
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La malattia paranale di Crohn rappresenta una condizione clinica complessa e invalidante. La chirurgia da sola è efficace nel migliorare i sintomi mediante il controllo della sepsi, ma è raramente associata alla guarigione definitiva. L'introduzione dei farmaci biologici ha aumentato le possibilità di chiusura definitiva delle fistole. Tuttavia molti pazienti non rispondono a questo trattamento bio-chirurgico combinato. Il ruolo del mucosal healing del retto ottenuto con i farmaci non è al momento ancora chiaro. L'obiettivo del presente studio è quello di identificare possibili terapia alternative per pazienti non responsivi ai biologici. Lo studio ha valutato efficacia e sicurezza della chirurgia riparativa, confezionamento di flap mucosi endorettali e posizionamento di protesi biologiche, nei pazienti non responsivi ai biologici ma che grazie ad essi abbiano ottenuto un mucosal healing del retto.Perianal Crohn's disease is a complex and disabling clinical condition. surgical treatment alone is effective in relieving symptoms with sepsis control but it is associated with a low healing rates. The introduction of biological drugs increased the rate of healing of perianal fistulas. However many patients are still not responders to bio-surgical approach. The role of rectal mucosal healing obtained with biologics in these patients is still non well defined yet. The aim of the present study was to investigate possible rescue treatments for these patients. The study analyzed the efficacy and safety of surgical primary repair,such as endorectal advancement flap and biological plug placement,in patients not responders to biologics but who obtained a rectal mucosal healing.
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Panchadcharam, Chandrawathani. "Problems in the control of nematode parasites of small ruminants in Malaysia : resistance to anthelmintics and the biological control alternative /." Uppsala : Dept of Biomedical Sciences and Veterinary Public Health, Swedish Univ. of Agricultural Sciences, 2004. http://epsilon.slu.se/v172.pdf.
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Vashist, Usha. "Aspectos biológicos da inoculação experimental e atividade malaricida da 4-(6-mercaptopurina)-7-cloroquinolina em Gallus gallus Linnaeus, 1758 experimentalmente infectados por Plasmodium (Novyella) juxtanucleare Versiani & Gomes, 1941 (Apicomplexa, Plasmodiidae)." Universidade Federal de Juiz de Fora (UFJF), 2007. https://repositorio.ufjf.br/jspui/handle/ufjf/2915.
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Plasmodium juxtanucleare é o agente causador da malária aviária que ocorre em alguns estados do Brasil. Esta malária está relacionada a diversos sinais clínicos e pode causar danos em criações rústicas de aves. O modelo aviário já foi utilizado para a investigação de drogas no combate à malária e hoje em dia o modelo mais utilizado é o Plasmodium berghei em roedores. A busca por anti-maláricos e malaricidas é de extrema relevância. O objetivo deste trabalho foi verificar o efeito da 4-(6-MERCAPTOPURINA)-7-CLOROQUINOLINA, uma substância recém sintetizada a partir da cloroquina, sobre a malária aviária em Gallus gallus e aprimorar o modelo aviário para testes de potenciais malaricidas. Para o encontro de uma ave doadora, foram visitadas no município de Juiz de Fora duas granjas e feitos esfregaços sangüíneos de 30 aves. A prevalência foi de 100%. Dentre as 30 aves examinadas, as seis com os maiores valores de parasitemia foram adquiridas e levadas para o laboratório. Para verificar qual o melhor dia para a retirada de sangue de aves infectadas e imunossuprimidas pelo acetato de metilprednisolona, cinco das seis aves receberam em dose única este imunossupressor e uma serviu como controle. A parasitemia das aves foi acompanhada por 26 dias após o dia da imunossupressão, por meio de esfregaços sangüíneos preparados a cada dois dias. Também foram aferidos o peso e temperatura corporal e feitos microhematócritos sangüíneos. Verificou-se que ao 10º dia pós-imunossupressão ocorreu pico de parasitemia. Houve queda de peso corporal e correlação com a parasitemia. Ocorreu pouca variação na temperatura corporal e hematócrito e não houve correlação destes com a parasitemia. Em outras oito aves adquiridas em casa comercial com 15 dias de idade, foram realizadas infecções experimentais com sangue inoculado via intramuscular e via intraperitonial nas doses de 0,3mL e 0,5mL para as duas vias. Durante um mês as aves tiveram o valor médio de parasitos acompanhado para comparar qual a via mais efetiva e se havia diferença entre as doses testadas no estabelecimento da infecção. Não foi observada diferença entre as xv dosagens, mas foi possível verificar que a infecção via intraperitonial atinge mais rapidamente o pico de parasitemia, com médias de parasitos mais altas, entretanto ao fim do experimento o número total de parasitos quase não diferiu entre as doses e vias. Para testar o efeito malaricida da 4-(6-MERCAPTOPURINA)-7-CLOROQUINOLINA, uma droga derivada da cloroquina, recém sintetizada, foram infectados 45 pintos, Leghorn branco, via intramuscular. As aves foram separadas em quatro grupos experimentais com 15 aves por grupo (Grupo1- não infectado, Grupo 2- infectado e sem tratamento, Grupo 3- infectado e tratado com a cloroquina e grupo 4- infectado e tratado com o derivado da cloroquina). A droga foi administrada via gavagem por 4 dias consecutivos na dose de 100mg/Kg de peso vivo. Para a avaliação do efeito malaricida da droga, as aves tiveram o número médio de parasitos encontrados acompanhados por esfregaços sangüíneos feitos a cada dois dias após o décimo dia da inoculação. Também foram aferidos o peso e temperatura corporal a cada dois dias e hematócrito a cada quatro dias. O derivado da cloroquina teve atividade malaricida, mantendo a parasitemia mais baixa em relação ao grupo controle não tratado e ao grupo controle tratado com a cloroquina. Entretanto em todos os grupos a parasitemia se manteve baixa. Sugere-se a investigação da ação malaricida desta droga em modelos com P. berghei ou culturas com P. falciparum.
Plasmodium juxtanucleare is the agent of the avian malaria that occurs in some states of Brazil. This malaria is related to several clinical signs and it can cause damages in the poultry section. The aviary model was already used for the investigation of drugs in the combat to the malaria and nowadays the model more used is the Plasmodium berghei in rodents. The search for anti-malarial drugs is of extreme importance. The aim of this study was to accomplish experimental infections of Plasmodium juxtanucleare in Gallus gallus and to test a substance recently synthesized, the 4-(9H-purin-6-ylthio)-7-cloroquinoline, derived of the cloroquine, to verify their effects on the avian malaria and to improve the aviary model for these types of tests. For a bird donor's encounter, two chicken farms were visited in the Juiz de Fora city and blood smears made in 30 hens. The prevalence was 100%. Among the 30 examined hens, six with the largest parasitemia values had been acquired and taken to the laboratory. To verify which the best day to retreat the blood to infected hens, five of the six hens received only dose of the imunossupressor substance (metilprednisolon acetate) and one served as control. The parasitaemia of the hens was accompanied by 26 days after the day of the imunossupression, through blood smears prepared each two days. The weight and corporal temperature were checked and made blood hematocrits. It was verified that to the 10th day powder-imunossupression it happened parasitaemia pick. There were fall of body weight and correlation with the parasitaemia. There was a little variation in the body temperature and hematocrite and there was not correlation of these with the parasitaemia. In other eight acquired hens in commercial house with 15 days old, experimental infections were accomplished with blood inoculated through intramuscle and intraperitoneally in the 0,3mL and 0,5mL for the two routes. During one month the hens had the value of parasites accompanied to compare which the most effective route and difference among the doses tested in the establishment of the infection. Significant difference was not observed among the xvii doses but it was possible to verify that the infection through intraperitonial reaches the parasitemia pick more quickly, with higher averages of parasites, however to the end of the experiment the total number of parasites differed hardly between the doses and routes. To test the effect a derived drug of the cloroquine, 45 chicks were infected, white Leghorn, through intramuscle route . The hens were separate in four experimental groups, 15 chicks for group (Group1 - no infected, Group 2 - infected and without treatment, Group 3 - infected and treated with the cloroquine and Group 4 - infected and treated with derived of the cloroquine) The drug was administered four consecutive days in the 100mg/Kg of alive weight dose. For the evaluation of the antimalarial effect of the drug, the hens had the number of parasites accompanied by blood smears done each two days after the tenth day of the inoculation. Also the weight and corporal temperature were checked each two days and hematocrit four days. Derived of the cloroquine had antimalarial activity, reducing the number of parasites and maintaining the lowest parasitaemia in relation to the group not treated and to the group treated with cloroquine.
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Tostes, Raquel Cristina. "Malária em aves silvestres da Mata Atlântica de Minas Gerais mantidas em cativeiro: diagnóstico parasitológico e molecular, e caracterização bioquímica e histopatológica." Universidade Federal de Juiz de Fora, 2013. https://repositorio.ufjf.br/jspui/handle/ufjf/1208.
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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais
A malária é uma das doenças mais comuns entre as aves e vem causando danos às espécies em todo o mundo, podendo em muitos casos ser fatal. Pode causar alterações fisiológicas em diferentes órgãos, as quais podem ser caracterizadas por análises bioquímicas e por análises histopatológicas. Assim, os objetivos do presente trabalho foram verificar a prevalência e parasitemia de parasitos maláricos em aves silvestres em cativeiro da Mata Atlântica em Minas Gerais e realizar a caracterização bioquímica sérica e histopatológica das aves infectadas. Para isso, foram coletadas amostras de sangue de 119 aves e feitos esfregaços sanguíneos para cálculo da prevalência e parasitemia. Foi utilizada ainda a biologia molecular para cálculo da prevalência, comparando os resultados à microscopia. Para as análises bioquímicas e histopatológicas foram utilizadas seis aves infectadas e eutanasiadas pelo IBAMA. A prevalência média nas análises microscópicas foi de 83,19% e a parasitemia de 1,51%, enquanto que na biologia molecular foi de 82,5%. Os cortes histológicos demonstraram alterações no fígado, rins, baço e coração, provavelmente secundárias à infecção malárica, destacando-se no fígado, baço e rins a presença de pigmentação acastanhada, sugestiva de pigmento malárico ou hemozoína. Os valores das análises bioquímicas, valores da enzima ALT e de proteínas totais foram aparentemente mais altos em aves com parasitemia maior, diferente dos valores da AST, que foram aparentemente normais. É necessário considerar que parâmetros bioquímicos podem ser alterados por fatores internos e externos, o que pode explicar a diferença dos valores das enzimas encontrados no presente estudo com valores para outras espécies relatados na literatura. Sugere-se estudos visando estabelecer valores de referência de análises bioquímicas, que podem ser utilizadas como ferramenta para caracterização da saúde das aves silvestres.
Malaria is one of the most common diseases among birds and has caused damage to the species in all the world and can often be fatal. It can cause physiological changes, which can be characterized by biochemical and histopathological analysis. The aim of this study were to determine the prevalence and the parasitemias and malarial parasites in captive wild birds from Floresta Atlântica in Minas Gerais and to characterize serum biochemistry and histopathology of infected birds. For this, blood samples were collected from 119 birds, prepared blood smears for estimating the prevalence and the parasitemias. For biochemical analysis and histopathological features were analyzed six and infected birds. The mean prevalence in blood smears was 83.19% and mean parasitemia 1.51%, while in the molecular biology was 82,5%. Histological sections demonstrated alterations in liver, kidney, spleen and heart, probably by to malaria infection. In the liver, spleen and kidneys the presence of brownish pigmentation, suggestive of malarial pigment, the hemozoin. The values enzyme ALT and total proteins were apparently higher in birds with parasitemia greater than those of AST values that were apparently normal. You must consider that biochemical parameters can be changed by internal and external factors, which may explain the difference in the values of enzymes found in the present study with values for other species reported in the literature. It is suggested studies to establish reference values for biochemical analysis, which may be used as a tool to characterize the health of the birds.
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Siska, Veronika. "Human population history and its interplay with natural selection." Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/284164.
Full textAbstract:
The complex demographic changes that underlie the expansion of anatomically modern humans out of Africa have important consequences on the dynamics of natural selection and our ability to detect it. In this thesis, I aimed to refine our knowledge on human population history using ancient genomes, and then used a climate-informed, spatially explicit framework to explore the interplay between complex demographies and selection. I first analysed a high-coverage genome from Upper Palaeolithic Romania from ~37.8 kya, and demonstrated an early diversification of multiple lineages shortly after the out-of-Africa expansion (Chapter 2). I then investigated Late Upper Palaeolithic (~13.3ky old) and Mesolithic (~9.7 ky old) samples from the Caucasus and a Late Upper Palaeolithic (~13.7ky old) sample from Western Europe, and found that these two groups belong to distinct lineages that also diverged shortly after the out of Africa, ~45-60 ky ago (Chapter 3). Finally, I used East Asian samples from ~7.7ky ago to show that there has been a greater degree of genetic continuity in this region compared to Europe (Chapter 4). In the second part of my thesis, I used a climate-informed, spatially explicit demographic model that captures the out-of-Africa expansion to explore natural selection. I first investigated whether the model can represent the confounding effect of demography on selection statistics, when applied to neutral part of the genome (Chapter 5). Whilst the overlap between different selection statistics was somewhat underestimated by the model, the relationship between signals from different populations is generally well-captured. I then modelled natural selection in the same framework and investigated the spatial distribution of two genetic variants associated with a protective effect against malaria, sickle-cell anaemia and β⁰ thalassemia (Chapter 6). I found that although this model can reproduce the disjoint ranges of different variants typical of the former, it is incompatible with overlapping distributions characteristic of the latter. Furthermore, our model is compatible with the inferred single origin of sickle-cell disease in most regions, but it can not reproduce the presence of this disorder in India without long-distance migrations.
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Duque, Juliane Aparecida Marinho. "Análise da função fagocítica de macrófagos de animais infectados com Plasmodium berghei NK65." Universidade Federal de Juiz de Fora (UFJF), 2012. https://repositorio.ufjf.br/jspui/handle/ufjf/4280.
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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
A malária é uma importante doença tropical com distribuição mundial. A doença é causada por protozoários do gênero Plasmodium que infectam humanos e outras espécies animais. Modelos experimentais de infecção por Plasmodium berghei NK65A (PbNK65A) em camundongos Balb/c auxiliam na compreensão da doença humana. A resposta imune à malária é extremamente complexa. Os macrófagos apresentam-se como importantes células no combate ao estágio eritrocítico do parasito. O trabalho buscou avaliar diferentes aspectos da função destas células durante a infecção por PbNK65. Os resultados demonstraram que a parasitose não altera a frequência relativa da população de macrófagos peritoneais nos camundongos. Porém, os animais infectados, apresentaram maior expressão de moléculas co-estimuladoras, principalmente CD80, e expressiva redução da capacidade de fagocitar hemácias parasitadas ao longo da infecção. A produção da IL-12, citocina importante para ativação da resposta celular também foi intensamente prejudicada pelo parasito no decorrer da infecção. Diante dos resultados, podemos sugerir que a infecção por Plasmodium berghei NK65 interfere na resposta imune inata, e esta pode ser atribuída ao caráter negativo da infecção sobre o macrófago, que possui suas principais funções alteradas, como a fagocitose e a produção de IL-12. Ainda que a co-estimulação seja preservada e até elevada neste modelo, é insuficiente para o hospedeiro gerar uma resposta celular eficiente que limitaria a proliferação de Plasmodium e, sobretudo, a morte do hospedeiro.
Malaria is a major tropical disease with worldwide distribution. The disease is caused by protozoa of the genus Plasmodium which infects humans and other animal species. Experimental models of infection by Plasmodium berghei NK65A (PbBNK65A) in Balb/c mice is important in the understanding of human disease. Immune response to malaria configures itself extremely, involving different elements. Macrophages are important cells against the erythrocytic parasite stage. Thus, the study aimed to evaluate different aspects of macrophage functions during infection by PbNK65A. The results showed that the parasite does not alter the frequency on peritoneal macrophages. However, the infected animals showed higher expression of coestimulatory molecules, mainly CD80 and significant reduction in the ability to phagocytosis infected erythrocytes during the infection. The production of IL-12 cytokine, important for activation of the cellular response, was also affected during infection. Thus, we suggest that infection by Plasmodium affects the innate immune response, and this can be attributed to the negative character of the infection on the macrophages, which has changed its principal functions, such as phagocytosis and IL-12 production. Although co-stimulation is preserved and even higher in this model, is insufficient to generate a host cell response that limits the proliferation of Plasmodium, and especially the host death.
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Soares, Sara Malaguti Andrade. "Impactos da obesidade no desenvolvimento de malária grave murina causada por Plasmodium berghei - ANKA: avaliação de parâmetros parasitológicos e imunológicos." Universidade Federal de Juiz de Fora (UFJF), 2016. https://repositorio.ufjf.br/jspui/handle/ufjf/4972.
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FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais
A obesidade é motivo de preocupação para a saúde pública em todo o mundo. Apesar de existirem muitos estudos sobre seu impacto no sistema imunológico, a influência nas doenças infecciosas é pouco relatado. A incidência da obesidade vem aumentando em países em desenvolvimento, assim é de grande importãncia o estudo do papel da obesidade na resposta imunológica a patógenos, principalmente em doenças infecciosas de grande relevãncia como a malaria. A obesidade é caracterizada por uma inflamação sistêmica de baixo grau crõnica, e acredita-se que as manifestações complicadas da malária, como a malaria cerebral, injuria respiratória, denominada malária grave, podem ser resultado da resposta inflamatória exagerada causada pelo sequestro de hemácias infectadas nos vasos endoteliais de orgãos vitais como cérebro e pulmão. Portanto a inflamação na obesidade pode alterar o curso da infecção do Plasmodium berguei ANKA, parasitas causadores da malária cerebral em modelo murino. Neste trabalho, investigamos a influência da obesidade na resposta imune frente à infecção por Plasmodium berguei ANKA. Para isso foram utilizados camundongos C57BL/6 machos, com idade de 4 a 6 semanas, alimentados durante 12 semanas por uma dieta hiperlipídica com 60% das quilocalorias advindas de lipídeos. Após esse período os animais foram infectados com a cepa ANKA de Plasmodium berguei. Nos animais alimentados com a dieta hiperlipídica, observou-se aumento do peso corporal, assim como da gordura perigonadal dos animais alimentados pela dieta hiperlipídica, sem aumento do consumo de ração. A resistência ao desenvolvimento da malária grave foi observada nos animais obesos; além de conseguir controlar a parasitemia, . Somente esses animais sobreviveram à infecção, por 25 dias após o desafio, sem apresentar sintomas clínicos da doença, ao contrário, os não obesos infectados, vieram a óbito após oito dias de infecção. Foram observadas diferenças no perfil celular dos animais obesos infectados quando comparados aos controles infectados, sugerindo que a inflamação prévia dos animais obesos pode ter influenciado o curso da infecção. Assim, os resultados indicam que alterações na resposta imunológica do camundongo obeso conseguem protege-lo contra o desenvolvimento da malaria grave.
Obesity is a public heaith concern currentiy affecting worldwide, aithough there are many studies on the impact of obesity on the immune system, the various aspects of the association between obesity and infection is seidom reported. The incidence of obesity is increasing in the developing countries, and it is very important to study the role of obesity in the immune response to pathogens, especially infectious diseases such as maiaria. Obesity is characterized by a iow-grade, systemic, chronic infiammation and it is believed that the complicated manifestations of maiaria, as severe maiaria, can be the result of an exaggerated inflammatory response caused by sequestration of infected erythrocytes to endothelial vesseis of vital organs such as brain and lung. So infiammation in obesity may alter the course of infection of Plasmodium berguei ANKA, parasites that cause cerebral maiaria in mice. In this work, we investigated the influence of obesity on the immune response to infection by Plasmodium berguei ANKA. For this, mate C57BL/6 mice aged 4 to 6 weeks were used, fed by a high fat diet with 60% of kilocalories from lipid, for 12 weeks. After this period the animais were infected with the strain ANKA of Plasmodium berguei. There was an increase in body weight as well as the perigonadal fat in animais fed with the high fat diet, without increasing the food intake, from the second week of dieting. The resistance to the deveiopment of severe maiaria was observed in the obese animais, beside of control the parasitemia, oniy those animais survived the infection for 25 days post challenge, without any clinicai symptoms of the disease, unlike infected non obese, who died after eight days of infection. Differences were observed in the cell profile of infected obese animais compared to infected controls, suggesting that prior infiammation in obese animais may have infiuenced the course of infection. Thus, the resuits indicate that changes in the immune response of obese mice can protect against the deveiopment of severe maiaria.
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Silva, José Márcio Fernandes da. "Avaliação da ação antimalárica de compostos sintéticos derivados de quinolina em cultura de Plasmodium falciparum." Universidade Federal de Juiz de Fora (UFJF), 2013. https://repositorio.ufjf.br/jspui/handle/ufjf/5293.
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FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais
As dificuldades de adequação, aplicação e manutenção das estratégias de controle nos locais onde a malária é endêmica contribuem, em grande parte, para que a doença seja considerada o maior flagelo da humanidade. Neste contexto, destaca-se o amplo desenvolvimento de resistência dos plasmódios aos mais variados compostos que foram ou que ainda são utilizados na terapêutica antimalárica, o que faz do tratamento efetivo dos casos um grande desafio a cada ano. Diante disso, torna-se inquestionável a necessidade da descoberta de novas moléculas que possam, no futuro próximo, estar disponíveis para inclusão em medicamentos destinados à cura efetiva da infecção. Este estudo investigou a atividade antiplasmodial de 10 moléculas sintéticas derivadas de quinolinas em cultura de P. falciparum, bem como sua atividade citotóxica em células HeLa e mononucleares do sangue periférico. Das 10 moléculas, 5 estão conjugadas a sulfonamidas enquanto as demais possuem em sua estrutura um grupo hidrazina. Independentemente do grupamento farmacofórico integrado ao anel quinolínico, nenhuma molécula foi citotóxica para células HeLa ou linfócito humano em baixas concentrações. No que se refere a atividade antimalárica, 60% das moléculas foram altamente ativas contra P. falciparum (CI50 variando de <0,195µg/mL a 3,12µg/mL) e 10% totalmente inativas (CI50>50µg/mL). Ao analisarmos o índice de seletividade das moléculas, somente dois compostos não foram seletivos para o parasito (RMP103 e RMP107). Dentre as moléculas mais seletivas destacaram-se aquelas conjugadas ao grupo hidrazina, sobretudo RMP105 que foi >1800 vezes mais seletiva para plasmódio quando comparada a droga de referência. Portanto, por apresentarem alta atividade antimalárica e baixa toxicidade em células humanas, com elevado índice de seletividade para os plasmódios, as moléculas testadas nesse estudo podem ser consideradas boas alternativas para se tornarem medicamentos antimaláricos e auxiliarem de maneira eficaz no combate a doença.
The difficulties found in adapting, implementing and maintaining control strategies in malaria endemic regions are largely responsible for the spread of this disease, which is considered one of the greatest scourges of mankind. In this context, there is a widespread development of plasmodia resistance to various compounds that have been or are still used in antimalarial therapy, making effective treatment of the cases a constant challenge. Therefore, there is an unquestionable need for discovery of new molecules that may, in the near future, be available for inclusion in effective medicines for the cure of the infection. This study investigated the antiplasmodial activity of 10 synthetic molecules (derived from quinoline) in cultured P. falciparum, and their cytotoxic activity against HeLa cells and peripheral blood mononuclear cells. Of the 10 molecules tested, 5 are combined to sulfonamides, while the others have in their structure a hydrazine group. Regardless of the grouping pharmacophore integrated into the quinoline ring, all the molecules tested were not cytotoxic to HeLa cells or human lymphocytes, at low concentrations. Concerning the antimalarial activity, 60% of the molecules were highly active against P. falciparum (CI50 ranging from <0.195 µg / ml to 3.12 µg / mL) and 10% totally inactive (CI50 > 50μg/mL). By analyzing the selectivity index of molecules, only two compounds were not selective for the parasite (RMP103 and RMP107). Among the more selective molecules, the highlights were those linked to the hydrazine group, especially RMP105 which was >1800 times more selective for plasmodium compared to the reference drug. Therefore, due to their high antimalarial activity and low toxicity in human cells, with a high selectivity for Plasmodium, the molecules tested in these studies can be considered good alternatives to become antimalarial drugs and assist effectively in combating the disease.
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Díaz, Varela Míriam. "Exploration of Extracellular Vesicles as a Novel Approach for Antigen Discovery and Vaccine Development against Plasmodium vivax Malaria." Doctoral thesis, Universitat de Barcelona, 2019. http://hdl.handle.net/10803/668981.
Full textAbstract:
Plasmodium vivax is the most geographically widespread human malaria parasite. Research on this parasite needs to be expanded in order to develop adequate tools for its control such as a highly effective vaccine. One particular feature of P. vivax is its preference to invade immature red blood cells, also known as reticulocytes. Interestingly, ultrastructural studies performed on
reticulocytes enabled the discovery of exosomes, extracellular vesicles (EVs) of endocytic origin. These vesicles were initially seen as a selective cargo-disposal pathway, but later works showed the involvement of exosomes, and other extracellular vesicles, in a variety of biological processes. Importantly, exosomes derived from reticulocytes infected with P. yoelii, a murine reticulocyte-prone parasite that resembles P. vivax, contained parasite proteins. When used in CpG-adjuvanted immunizations, exosomes were able to elicit long-lasting protective responses. This thesis hypothesizes that exosomes derived from P. vivax-infected reticulocytes contain parasite antigens and stimulate immune responses. We evaluated the potential of circulating extracellular vesicles from P. vivax infections as a source of antigens and as activators of T-cell responses, and explored human reticulocyte-derived exosomes as a vaccine platform against P. vivax malaria.
We isolated EVs from plasma of P. vivax-infected patients and determined their protein composition by mass spectrometry-based proteomics in order to unveil their potential use in antigen discovery. We found parasite proteins associated to these vesicles that could serve as antigens. Indeed, two of the identified vivax proteins present promising cytotoxic T-cell epitopes as evidenced by in silico analysis. Moreover, we detected HLA class I molecules and observed an altered protein cargo in vesicles from vivax patients compared to healthy donors, thus suggesting that circulating EVs might affect the course of P. vivax infection. Next, we evaluated the in vitro interaction of these vesicles with leukocyte populations from the human spleen, given the importance of this organ in the induction of adaptative immune responses. Remarkably, we observed a significant interaction of monocytes, B-cells and T-cells with vesicles from patients compared to healthy individuals. We studied the capacity of these vesicles to activate T-cells, and preliminary results indicate that circulating vesicles from infections might stimulate CD8+ T-cell responses. Recent studies highlighted the role of cytotoxic CD8+ T-cell responses against P. vivax blood-stage parasites. In parallel, we studied the proteomic composition of exosomes derived from human reticulocytes and analyzed their ability to interact with antigen-presenting cells. We identified over 300 proteins in these vesicles, including HLA class I molecules, and found that these exosomes could be taken up by antigen-presenting cells, thus suggesting their contribution to the presentation of antigens. Collectively, our results indicate that EVs from vivax infections can be used in antigen discovery and might contribute to cell-mediated immune responses that could be critical for vivax control. In particular, reticulocyte-derived exosomes represent a potential vaccine platform to be furtherly explored. We believe this work has provided novel insights for vaccine development against P. vivax malaria.Plasmodium vivax es el parásito que causa malaria humana más extendido geográficamente. Se ha de ampliar la investigación sobre este parásito para desarrollar herramientas adecuadas para su control, entre ellas, una vacuna altamente efectiva. Una característica particular de P. vivax es su preferencia por invadir glóbulos rojos inmaduros, también conocidos como reticulocitos. Curiosamente, estudios ultraestructurales realizados en reticulocitos permitieron el descubrimiento de exosomas, vesículas extracelulares (VEs) de origen endocítico. Los exosomas y otras vesículas extracelulares, fueron vistos inicialmente como una vía selectiva de eliminación de proteínas obsoletas, pero en la actualidad, se sabe que participan en una gran variedad de procesos biológicos. Los exosomas derivados de reticulocitos infectados con P. yoelii, un parásito propenso a invadir reticulocitos murinos que se asemeja a P. vivax, contienen proteínas parasitarias. Cuando estos exosomas se usan en inmunizaciones con adyuvante de CpG son capaces de provocar respuestas protectoras duraderas. Esta tesis plantea la hipótesis de que los exosomas derivados de reticulocitos infectados con P. vivax contienen antígenos del parásito y pueden estimular respuestas inmunes. Evaluamos el potencial de las VEs circulantes en infecciones de P. vivax como fuente de antígenos y como activadoras de respuestas de células T. Además, exploramos los exosomas derivados de reticulocitos humanos como una plataforma de vacunación contra la malaria vivax. Aislamos VEs del plasma de pacientes infectados con P. vivax y determinamos su composición proteica mediante proteómica basada en espectrometría de masas para investigar su potencial uso en el descubrimiento de antígenos. Encontramos proteínas del parásito asociadas a estas vesículas, las cuales podrían actuar como antígenos. De hecho, el análisis in silico de dos de estas proteínas reveló prometedores epítopos citotóxicos de células T. Además, detectamos moléculas HLA clase I y observamos un alterado contenido de proteínas en las vesículas de pacientes con vivax en comparación con donantes sanos, lo que sugiere que los VEs circulantes podrían afectar el curso de la infección por P. vivax. A continuación, evaluamos la interacción in vitro de estas vesículas con poblaciones leucocitarias del bazo humano, dada la importancia de este órgano en la inducción de respuestas inmunes adaptativas. Observamos una interacción significativamente elevada de monocitos, células B y células T con vesículas de pacientes en comparación con VEs de individuos sanos. Estudiamos la capacidad de estas vesículas para activar las células T, y los resultados preliminares indican que las vesículas circulantes de infecciones de vivax podrían estimular las respuestas de las células T CD8+. Recientes estudios han destacado el posible papel de las respuestas citotóxicas de las células T contra los parásitos de la etapa sanguínea de P. vivax. Paralelamente, analizamos la composición proteómica de los exosomas derivados de reticulocitos humanos y determinamos su capacidad para interactuar con células presentadoras de antígenos. Identificamos más de 300 proteínas en estas vesículas, incluidas las moléculas HLA de clase I, y descubrimos que estos exosomas podían ser internalizados por células presentadoras de antígenos, lo que sugiere su contribución a la presentación antigénica. En conjunto, nuestros resultados indican que las VEs de las infecciones por vivax pueden usarse en el descubrimiento de antígenos y pueden contribuir a respuestas inmunes mediadas por células que podrían ser críticas para el control de vivax. En particular, los exosomas derivados de reticulocitos representan una potencial plataforma de vacuna. Creemos que este trabajo ha proporcionado nuevas ideas para el desarrollo de vacunas contra la malaria por P. vivax.
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TORRES, Marjorie Lujan Marques. "Efeito protetor da ração enriquecida com açaí (Euterpe oleracea) no quadro de malária cerebral experimental." Universidade Federal do Pará, 2018. http://repositorio.ufpa.br/jspui/handle/2011/10060.
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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico
FAPESPA - Fundação Amazônia de Amparo a Estudos e Pesquisas
A malária cerebral (MC) é uma das complicações mais severas atribuídas à infecção pelo protozoário Plasmodium falciparum, ganhando destaque nas taxas de mortalidade infantil em áreas endêmicas. Esta enfermidade apresenta uma patogênese complexa e ainda pouco elucidada, estando associada a alterações cognitivas, comportamentais e motoras. Visando ampliar os conhecimentos a respeito desta patologia e procurando os benefícios atribuídos ao consumo diário de antioxidantes, o principal objetivo deste trabalho é avaliar o possível efeito protetor do fruto da Euterpe oleracea (açaí) durante a evolução do quadro de malária cerebral experimental (MCE) induzida em modelo murino por meio da inoculação da cepa ANKA de Plasmodium berghei (PbA). Para tal, utilizaram-se camungondos da linhagem albino suíço, os quais foram inoculados intraperitonealmente (i.p.) com 10⁶ de eritrócitos parasitados. Os animais (fêmeas e machos entre 4 a 6 semanas) foram divididos em quatro grupos, dentre os quais os grupos Açaí e PbA+Açaí foram mantidos com uma dieta exclusiva com ração enriquecida com açaí, e aos grupos Controle e PbA foram proporcionadas somente ração padrão durante os 22 dias de experimento. Para caracterização do quadro de MCE foram avaliados diversos parâmetros como o surgimento dos sinais clínicos, curva de sobrevivência, parasitemia (%), ganho de massa corpórea e permeabilidade vascular. Para avaliação das alterações comportamentais e locomotoras dos animais foi utilizado o protocolo SHIRPA. Observamos prolongamento de sobrevida dos animais infectados e tratados com dieta enriquecida com açaí, além de diminuição das alterações neurológicas decorrentes da exposição do parênquima cerebral. Este trabalho nos permitiu validar o desenvovimento do quadro de malária cerebral experimental (MCE) em modelo murino e avaliar o efeito neuroprotetor do açaí (Euterpe oleracea) no decorrer da doença.
Cerebral malaria (CM) is one of the most severe complications attributed to protozoal infection by Plasmodium falciparum, gaining prominence in infant mortality rates in endemic areas. It´s a complex pathogenesis and still little elucidated, being associated with cognitive, behavioral and motor changes. Aiming to broaden the knowledge about this pathology and looking for the benefits attributed to the daily consumption of antioxidants, the objective of this work is to evaluate the possible protective effect of Euterpe oleracea fruit (açaí) during evolution of experimental cerebral malaria (ECM) induced in murine model by means of inoculation of Plasmodium berghei (PbA), ANKA stain. For this, we used the Swiss line, which were inoculated intraperitoneally (i.p.) with 10⁶ of parasited erythrocytes. The animals (females and males between 4 and 6 weeks) were divided into four groups, among which Açaí and PbA+Açaí groups were maintained on a ration-exclusive diet enriched with açaí and the Control and PbA groups were given only standard ration during 22 days of experiment. To characterize the ECM framework, several parameters were evaluated such as the appearence of clinical signs, survival curve, parasitemia, body mass gain and vascular permeability. The SHIRPA protocol was used to evaluate the behavioral and locomotor changes in animals. We observed an extension of survival of the infected animals and treated with a diet enriched with acai berry, and decreased the neurological changes arising from the exposure of the cerebral parenchyma. This work allowed us to validate the development of the experimental brain malaria framework in murine model and evaluate the neuroprotective effect of Acai (Euterpe oleracea) in the course of the disease.
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Oliveira, Aline Mylena Guedes da Costa. "Avalia??o da atividade antimal?rica e citot?xica de plantas medicinais dos Biomas Caatinga e Amaz?nico." Universidade Federal do Rio Grande do Norte, 2011. http://repositorio.ufrn.br:8080/jspui/handle/123456789/13074.
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Previous issue date: 2011-03-15Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
Resistance of Plasmodium falciparum to the usual antimalarials, as well as their adverse effects and high cost, has led to the search of new drugs against malaria. Several of these have been developed from medicinal plants based on ethnopharmacology, including the most widely used antimalarials today: quinine and artemisinin. In the present study schizonticide activity of extracts and fractions of a number of medicinal plants from the Caatinga and Amazon biomes were assessed based on ethnopharmacological and chemosystematic information. These included Ximenia americana, Maytenus rigida, Sideroxylon obtusifolium, Stryphnodendro coriaceum, Bowdichia virgiliodes, Schinopis brasiliensis and Picrolemma sprucei, the last, an Amazon species. Antimalarial tests of blood schizonticides were conducted in Swiss mice infected with P. berghei and in vitro against P. falciparum. In vitro cytotoxicity studies were carried out using HeLa, CHO, 3T3, Raw and HEPG2 cell lines. Except for X. americana, all species exhibited in vivo or in vitro antimalarial activity, inhibiting parasitic growth by up to 79%. Extracts exhibited moderate toxicity with dosedependent kinetics. In this sense, ethnopharmacological and chemosystematic approaches were shown to be useful and promising tools in the search of new drugs. These findings represent a significant contribution to scientific knowledge of the antimalarial potential of Brazilian flora, thereby opening perspectives for the development of new antimalarials
A resist?ncia do Plasmodium falciparum aos antimal?ricos usuais, bem como os seus efeitos adversos e custo elevado, tornam necess?ria a busca de novos medicamentos contra a mal?ria. Diversos f?rmacos foram descobertos a partir de plantas medicinais com base na etnofarmacologia, inclusive os antimal?ricos mais usados atualmente; quinina e artemisinina. Neste trabalho foi avaliada a atividade esquizonticida de extratos e fra??es de algumas plantas medicinais dos Biomas da Caatinga e Amaz?nico a partir de um referencial etnofarmacol?gico e de quimiossistem?tica. S?o elas: Ximenia americana, Maytenus rigida, Sideroxylon obtusifolium, Stryphnodendro coriaceum, Bowdichia virgiliodes, Schinopis brasiliensis e Picrolemma sprucei, sendo esta ?ltima, uma esp?cie amaz?nica. Os testes antimal?ricos de esquizonticidas sangu?neos foram feitos em camundongos Swiss infectados com P. berghei e in vitro contra o P. falciparum. Estudos de citotoxicidade in vitro foram realizados utilizando as linhagens celulares HeLa, CHO, 3T3, Raw e HEPG2. A excess?o da X. americana, todas as esp?cies apresentaram atividade antimal?rica in vivo ou in vitro, inibindo o crescimento do parasito em at? 79%. Os extratos exibiram toxicidade moderada com cin?tica de atividade dose-dependente. Nesse contexto, a abordagem etnofarmacol?gica associada ao perfil quimiossistem?tico, se mostram ferramentas ?teis e promissoras na busca de novos f?rmacos, permitindo contribuir significativamente para o conhecimento cient?fico do potencial antimal?rico da flora brasileira e deste modo, abrir perspectivas para o desenvolvimento de novos antimal?ricos
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Couto, Joana Manuel Gonçalves Teixeira. "Transcriptomic analysis of Anopheles Stephensi salivary glands during the infection with Plasmodium Berghei." Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/14639.
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Mestrado em Biologia Molecular e CelularMalaria remains the leading cause of morbidity and mortality in tropical and subtropical regions, contributing to the emergence of 198 million clinical cases in 2013. The mosquito Anopheles stephensi is one of the most prevalent malaria vectors in the Asian region having recently been implicated in malaria resurgence in Djibouti. Using techniques as RNA sequencing, differentially expressed genes in the salivary glands of the mosquito in response to infection by Plasmodium berghei were identified. Some of these genes can be selected to evaluate their potential as targets for malaria transmission blocking. Among the genes with differentially expression resulting from the analysis of RNA-seq results and confirmation by qPCR, a gene related transport of Cl- and HCO3 2-, prestin, was upregulated after infection with P. berghei. This gene plays a crucial role in parasite invasion in the midgut and the optimization of the environment in which the parasite develops. For this reason, the silencing of this transcript was made to evaluate the function of prestin in salivary glands. The gene silencing, using RNA interference technique, allow inferring about the role or function of prestin gene in a particular metabolic or physiological process. After prestin gene silencing, the number of viable mosquitoes had a significant decrease in comparison with the control (β2M). There was also a significant decrease in the number of mosquitoes before injection and at the last day after injection. The number of sporozoites were not generally affected by silencing of prestin when compared with the control. To clarify other results obtained during the study, as the influence of the silencing of prestin in the survival of mosquitoes and the presence and number of sporozoites in the salivary glands, will be essential to perform qPCR to determine differential expression of this gene after silencing. Furthermore, it is also important to examine differential expression of off-target (ASTE006714) after silencing prestin, since the sequence of this gene have a high percentage of identity with prestin.
A malária continua a ser a principal causa de morbilidade e mortalidade nas regiões tropicais e subtropicais, contribuindo para o surgimento de 198 milhões de casos clínicos no ano de 2013. O mosquito Anopheles stephensi é um dos vectores de malária mais prevalentes na região asiática, tendo sido recentemente implicado no ressurgimento de malária em Djibouti. Através de técnicas como sequenciação de RNA, genes diferenciadamente expressos nas glândulas salivares deste mosquito em resposta à infecção por Plasmodium berghei foram identificados. Alguns destes genes podem ser selecionados para avaliar a sua potencialidade como alvos para bloqueio da transmissão da malária. Entre os genes com expressão diferencial resultante da análise dos resultados de RNA-seq e confirmação por qPCR, um gene relacionado com o transporte de Cl- e HCO3 2-, prestin, estava sobrexpresso após infeção com P. berghei. Este gene tem um papel crucial na invasão do parasita no intestino médio e na optimização do meio em que o parasita se desenvolve. Por esse motivo, o silenciamento deste transcrito foi efectuado para averiguar o papel funcional nas glândulas salivares. O silenciamento de genes utilizando a técnica de RNA de interferência permite inferir sobre o seu papel ou função num dado processo metabólico ou fisiológico. Após o silenciamento do gene prestin, o número de mosquitos viáveis apresentou um decréscimo significativo em comparação com o controlo (β2M). Também houve uma queda significativa entre o número de mosquitos antes da injeção e no último dia após injecção. O número de esporozoítos em geral não foi afectado pelo silenciamento da prestin quando comparado com o controlo. Para esclarecer resultados obtidos durante o estudo, tais como a influência do silenciamento da prestin na sobrevivência dos mosquitos e a presença e número de esporozoítos na glândulas salivares, seria fundamental realizar ensaios de qPCR para determinar a expressão diferencial deste gene após silenciamento. Além disso, será também importante analisar a expressão diferencial do off-target (ASTE006714) após silenciamento da prestin, uma vez que a semelhança da sequência entre este e a prestin é elevada.
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Olloquequi, González Jordi. "Cèl·lules inflamatòries en la Malaltia Pulmonar Obstructiva Crònica." Doctoral thesis, Universitat de Barcelona, 2010. http://hdl.handle.net/10803/848.
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La malaltia pulmonar obstructiva crònica (MPOC) és un procés patològic lent i progressiu caracteritzat per l'obstrucció permanent, i no totalment reversible, del flux d'aire als bronquíols i de l'increment de la compliància del pulmó com a resultat de la presència d'emfisema. L'origen de l'MPOC s'associa a una exposició crònica a gasos nocius i partícules, sobretot, al fum del tabac. Malgrat això, les causes de la patologia són multifactorials, i poden incloure tant trastorns genètics com factors ambientals.Els principals trets anatomopatològics de l'MPOC són l'engruiximent de la paret i el remodelatge tissular dels bronquíols i la destrucció emfisematosa del parènquima pulmonar. Malgrat que aquestes lesions histològiques són diferents, les cèl·lules inflamatòries implicades en ambdós processos són les mateixes. Davant d'aquest fet, el primer objectiu de la meva tesi va ser determinar si aquests dos fenotips histopatològics estan relacionats amb dos perfils limfocitaris diferents.
D'altra banda, malgrat que la progressió de l'MPOC s'ha associat amb la presència de fol·licles limfoides pulmonars, no hi ha dades disponibles sobre la densitat de les cèl·lules inflamatòries que formen aquestes estructures en l'àmbit de la malaltia. A més, també es desconeixen tant el patró de vascularització com l'expressió d'adrecines dels fol·licles limfoides pulmonars en l'MPOC. En conseqüència, el segon objectiu de la tesi va ser analitzar la prevalença, l'estructura, la localització, la vascularització i la proliferació/apoptosi cel·lulars dels fol·licles limfoides pulmonars en l'MPOC. Paral·lelament, també es van estimar les densitats fol·liculars dels limfòcits B i T, així com dels macròfags, de les cèl·lules dendrítiques i de les cèl·lules CD57+ en aquestes estructures.
Per tal d'assolir aquests objectius es van aplicar tècniques immunohistoquímiques i morfomètriques sobre teixit pulmonar procedent de 9 pacients no fumadors, de 18 fumadors sense l'MPOC, de 16 fumadors amb MPOC moderada i de 16 pacients amb MPOC molt greu sotmesos a un trasplantament bipulmonar.
Els resultats obtinguts demostren que els individus amb MPOC molt greu tenen una densitat de limfòcits T CD3+ i de limfòcits B significativament major als bronquíols en comparació amb el parènquima pulmonar. A més, els malalts d'MPOC presenten una densitat de limfòcits T CD8+ a l'epiteli bronquiolar significativament incrementada en comparació amb els individus no fumadors. Finalment, malgrat que la densitat parenquimàtica de limfòcits T CD8+ també es troba incrementada en els malalts d'MPOC, les densitats tant de limfòcits T CD8+ com de limfòcits B són similars en comparar el parènquima periemfisematós amb aquelles zones de parènquima no afectades per l'emfisema.
Pel que fa als fol·licles limfoides pulmonars, els resultats mostren una densitat fol·licular de cèl·lules CD57+ significativament major en els pacients d'MPOC quan se'ls compara amb els individus no fumadors i amb els fumadors sense l'MPOC (p < 0,05). A més, el percentatge de perfils fol·liculars que presenten apoptosi també és significativament major en els malalts d'MPOC (p = 0,03). D'altra banda, no s'observen diferències significatives entre grups quant a les densitats fol·liculars de la resta de cèl·lules inflamatòries, ni tampoc quant a la distribució de vasos sanguinis o limfàtics en aquestes estructures.
Així, els resultats presentats en aquest tesi corroboren l'existència d'un patró inflamatori bronquiolar en l'MPOC, que es caracteritza per la presència d'infiltracions mononuclears i de remodelatge tissular. No obstant això, el teixit parenquimàtic mostra una infiltració de limfòcits T CD8+ més lleu, la qual, a més, no es relaciona espacialment amb les zones de destrucció emfisematosa. D'altra banda, donat que les cèl·lules CD57+ són uns efectors importants de la resposta citotòxica i de la regulació immunitària, l'increment de la densitat fol·licular d'aquestes cèl·lules dóna suport a la hipòtesi que postula l'existència d'una disfunció immunitària local en l'MPOC.
In COPD, the histological lesions at both the small airways and lung parenchyma (wall thickening and tissue remodeling and emphysematous destruction, respectively) are definitely different. However, the inflammatory cells involved in both processes are the same. Moreover, although the presence of pulmonary lymphoid follicles (LF) has been associated with the progression of the disease, there is no information about the pattern of vascularization, expression of addressins or inflammatory cell densities within these structures in COPD.
Histological and immunohistochemical techniques were used to assess the distribution and cell density of CD3+, CD4+, CD8+ and B lymphocytes in small airways and parenchymal interstitium of 9 non-smokers, 18 smokers without COPD, 16 smokers with moderate COPD and 16 patients with very severe COPD. Also, the prevalence, structure, localization, vascularization and cell proliferation/apoptosis of LF, as well as the follicular density of the main inflammatory cells were assessed in our series.
The results of this study showed that CD3+ and B cell densities were significantly higher in small airways than parenchyma interstitium of very severe COPD patients. Furthermore, CD8+ cells were increased in the epithelium of airways of moderate COPD patients compared to non-smokers. Although CD8+ cell density was increased in parenchyma of COPD patients, CD8+ and B cell densities were similar when comparing periemphysematous and non-emphysematous alveolar interstitium. Regarding LF, those of COPD patients showed a significantly higher density of CD57+ cells. Moreover, the percentage of LF profiles with cell apoptosis was also significantly higher in COPD patients. On the contrary, no significant differences among groups were observed in the follicular densities of other inflammatory cells, nor in the distribution of blood and lymphatic vessels within LF.
These results suggest that, although the small airways' wall of COPD patients shows a clear inflammatory pattern, with a high mononuclear infiltration and tissue remodeling, the parenchymal interstitium shows a milder CD8+ infiltration which, moreover, is not spatially related to emphysematous destroyed areas. Moreover, since CD57+ cells are important effectors of cytotoxicity and immune regulation, an increase of their follicular density supports the hypothesis of a local immune dysfunction in COPD.
KEYWORDS: cigarrette smoking, lung inflammation, emphysema, inflammatory cells, lymphoid follicles
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Shachykov, Andrii. "Neural modeling of human motor coordination inspired by biological signals aiming for parkinsonian gaits." Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0291.
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Cette thèse présente une plate-forme de simulation neuro-musculo-squelettique du système locomoteur humain pour reproduire des allures de marche saines ou altérées par la maladie de Parkinson, ou par d’autres troubles locomoteurs. Le premier chapitre s’intéresse aux grands principes du système locomoteur en se focalisant sur les structures neuronales du cerveau qui sont le siège des troubles parkinsoniens. La transmission à la moelle épinière des signaux de contrôle de l'activité musculaire au travers de plusieurs boucles fermées est décrite. Différents modèles neuronaux des troubles parkinsoniens issus de la littérature sont présentés. Le second chapitre présente le contrôleur neuronal implémenté dans la plate-forme. Il utilise un modèle original de «central pattern generators» (CPG) inspiré du réseau locomoteur spinal. Ce CPG peut générer des signaux rythmiques variables selon ses paramètres neuronaux contrôlés par des signaux descendants du cerveau. Les signaux des motoneurones du CPG sont appliqués en tant qu'excitation au modèle de muscles flexeur/extenseur. Le chapitre trois présente les simulateurs musculo-squelettiques GAIT2DE et OpenSim utilisés ainsi que les modifications apportées pour simuler, en boucle fermée, le système locomoteur marchant sur le sol et les retours proprioceptifs et extéroceptifs exploités par les CPGs. Le chapitre quatre concerne l'analyse du cycle de la marche et l'optimisation des paramètres du contrôleur. Le cycle de marche permet de comparer des données de simulation avec des paramètres de marche réelle, et d’optimiser le contrôleur à partir d'une analyse comparative utilisant la corrélation croisée. Le chapitre cinq présente les résultats obtenus avec les deux simulateurs en intégrant une circuiterie complète à base des CPGs et d’un réflexe du contrôle d’équilibre. Les résultats montrent qu’on peut générer différentes démarches plus ou moins coordonnées selon les paramètres neuronaux reproduisant ainsi les allures observées pour la maladie de Parkinson ou d’autres troubles connus en médecine. Le dernier chapitre conclu et propose certaines améliorations de la plate-forme dans son ensemble pour simuler des démarches dues à d’autres maladies neurodégénératives ou à l’impact de prothèses ou suite à des interventions chirurgicalesMy thesis aims to simulate the impact of motor disorders on the human gait to help non-invasive diagnosis of neurodegenerative diseases such as Parkinson's disease. Indeed, the simulation of the human locomotor system helps to deepen our understanding of the functioning of the human body by providing biological, biomechanical and kinematic data that would be difficult to collect otherwise and by helping to evaluate the coordination of a patient's movements to predict its condition after surgery. The goal of my thesis is, more specifically, to create a new platform for neuro-musculoskeletal simulation of the human locomotor system to reproduce healthy or altered walking gaits by Parkinson's disease or by disorders of the musculoskeletal system or locomotor disorders. The work presented includes several matters. Firstly, the main principles of the nervous system that control human locomotion are reviewed, by focusing on neural structures located in the brain and which are the sources of parkinsonian disorders. The neural controller of the simulation platform is based on an original model of central pattern generator (CPG) inspired by the spinal locomotor network and developed at LORIA in recent years. The musculoskeletal simulators are used in this thesis to obtain a closed-loop physical simulation of the locomotor system walking on the ground and whose proprioceptive and exteroceptive sensory feedback is used by the CPGs. The musculoskeletal simulator GAIT2DE was used with the OpenSim simulator which is more realistic and more used in Biomechanics field. The simulated gait analysis and controller parameter optimization are concerned followed by the results obtained with the simulators. These results show that it is possible to generate different walking patterns that are relatively stable and coordinated by modifying the neuronal parameters of GPCs. The simulation platform will allow to simulate abnormal gait due to different causes such as neurodegenerative diseases or the impact of the addition of artificial limbs (prostheses) and surgical interventions
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Dantas, Gracielle Rodrigues. "Avalia??o da atividade antimal?rica de extratos obtidos de algas marinhas no litoral do Rio Grande do Norte." Universidade Federal do Rio Grande do Norte, 2012. http://repositorio.ufrn.br:8080/jspui/handle/123456789/13079.
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Previous issue date: 2012-03-07Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
Malaria is a major parasitic disease worldwide, accounting for about 500 million cases and causing 2 million to 3 million deaths annually. Four species are responsible for transmitting this disease to humans: Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae and Plasmodium ovale. The parasite resistance to antimalarial drugs and the usual limitations of the vector control implications are contributing to the spread of the disease. The most of significant advances in the search for new antimalarial drugs is based on natural components, the main ones being currently used antimalarial drugs derived from plants. Research on natural products of marine origin (particularly algae) show that some species possess antiplasmodial activity. Knowing that the coast of Rio Grande do Norte is home to several species of algae, the present study was to evaluate, for the first time, the antimalarial activity of ethanolic extracts of seaweed Spatoglossum schroederi, Gracilaria birdiae and Udotea flabellum against Plasmodium falciparum 3D7 strain tests and in vitro using the murine model (Plasmodium berghei) for evaluation in vivo. These species were ground, macerated with ethanol for 24 hours and the extracts concentrated in rotaevaporador (45 ? C ? 5 ? C). For in vitro tests, the extracts were diluted and tested at concentrations between 100 and 1.56 μg/ml (seven concentrations in triplicate), in order to obtain IC50 of each extract. The cytotoxicity tests with macrophages and BGM were performed using the MTT colorimetric assay. BGM macrophages and cells were distributed in 96 wells per plate (1x 105 to macrophages and 1x104 cells per well for BGM) and incubated for 24h at 37 ? C. The ethanol extracts were diluted and tested at concentrations of 100 to 1,56 μg/ml (seven concentrations in triplicate). After periods of 24 hours of incubation with the extracts, 100 μg of MTT was added to each well, and 3 hours elapsed, the supernatant was removed and added 200 μl of DMSO in each well. The absorbance of each well was obtained by reading on a spectrophotometer at 570 nm filter. To evaluate the acute toxicity in vivo, Swiss mice received a single dose (oral) 2000 mg/kg/animal of each extract tested. The parameters of acute toxicity were observed for 8 days. For in vivo tests, Swiss mice were inoculated with 1x105 erythrocytes infected with P. berghei. The treatment was given first to fourth day after infection with 0.2 ml of the extracts in doses of 1000 and 500 mg//g animal. The negative control group received 0.2 ml of 2% Tween-20, whereas the positive control group received sub-dose of chloroquine (5 mg/kg/animal). The assessment of antimalarial activity was done by suppressing suppressing the parasitemia at 5 and 7 days after infection. The growth inhibition of parasites was determined relative to negative control (% inhibition = parasitaemia in control - parasitemia in sample / parasitemia control x 100), the mortality of animals was monitored daily for 30 days The results showed that algae Spatoglossum schroederi and Udotea flabellum showed antimalarial activity in vitro, with reduced parasitemia of 70.54% and 54, respectively. The extracts of the three algae tested showed moderate to high cytotoxicity. Algae S. schroederi and U. flabellum were active against P. berghei only at doses of 500 mg / kg with reduction ranging from 54.58 to 52.65% for the fifth day and from 32.24 to 47.34% for the seventh day, respectively. No toxicity was observed in vivo at the dose tested, over the 8 days of observation. Although preliminary data, the bioactive components in those possible seaweed may be promising for the development of new anti-malarial drugs
A mal?ria ? a maior doen?a paras?tica mundial, respons?vel por cerca de 500 milh?es de casos e causando 2 a 3 milh?es de mortes anualmente. Quatro esp?cies s?o respons?veis pela transmiss?o dessa doen?a ao homem: Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae e Plasmodium ovale. A resist?ncia do parasito aos antimal?ricos usuais e as limita??es existentes no combate ao vetor s?o implica??es que contribuem para a expans?o dessa parasitose. Os avan?os mais significativos na busca de novos medicamentos contra a mal?ria baseiam-se em componentes naturais, sendo os principais antimal?ricos atualmente utilizados derivados de plantas. Pesquisas com produtos naturais de origem marinha (particularmente as algas) mostram que algumas esp?cies possuem atividade antiplasm?dica. Sabendo que o litoral do Rio Grande do Norte abriga v?rias esp?cies de algas, o presente estudo consistiu em avaliar, pela primeira vez, a atividade antimal?rica dos extratos etan?licos das algas Spatoglossum schroederi, Gracilaria birdiae e Udotea flabellum contra a cepa 3D7 Plasmodium falciparum em testes in vitro e utilizando o modelo murino (P. berghei) para avalia??o in vivo. As algas foram trituradas, maceradas com etanol por 24 horas e os extratos concentrados em rotaevaporador (45? C ? 5?C). Para os testes in vitro, os extratos foram dilu?dos e testados nas concentra??es entre 100 e 1,56 μg/ml (sete concentra??es em triplicata), com a finalidade de obten??o da CI50 de cada extrato. Os testes de citotoxicidade com macr?fagos e c?lulas BGM foram realizados usando o ensaio colorim?trico MTT. Macr?fagos e c?lulas BGM foram distribu?das em 96 po?os por placa (1x 105 para macr?fagos e 1x104 c?lulas por po?o para BGM), sendo incubadas por 24h a 37?C. Os extratos etan?licos foram dilu?dos e testados nas concentra??es de 100 at? 1,56 μg/ml (sete concentra??es em triplicata). Ap?s per?odos de 24h de incuba??o com os extratos, 100 μl de MTT foi adicionado a cada po?o, e decorridas 3h, o sobrenadante foi removido e adicionou-se 200 μl DMSO em cada po?o. A absorb?ncia de cada po?o foi obtida atrav?s de leitura em espectrofot?metro com filtro de 570 nm. Para avaliar a toxicidade aguda in vivo, camundongos Swiss receberam dose ?nica (oral) de 2000 mg/kg/animal dos extratos testados. Os par?metros de toxicidade aguda foram observados durante 8 dias. Para os testes in vivo, camundongos Swiss foram inoculados com 1x105 hem?cias infectadas com Plasmodium berghei. O tratamento deu-se do primeiro ao quarto dia ap?s a infec??o, com 0,2 ml dos extratos em doses de 1000 e 500 mg/kg/animal. O grupo controle negativo recebeu 0,2 ml de Tween-20 2%, enquanto que o grupo controle positivo recebeu sub-dose de cloroquina (5 mg/kg/animal). A avalia??o da atividade antimal?rica foi feita atrav?s da supress?o da parasitemia no 5? e 7? dias ap?s infec??o. A inibi??o do crescimento dos parasitos foi determinada em rela??o ao grupo controle negativo (% inibi??o = parasitemia do controle parasitemia com amostra/ parasitemia do controle x 100); a mortalidade dos animais foi acompanhada diariamente por 30 dias. Os resultados mostraram que as algas Spatoglossum schroederi e Udotea flabellum apresentaram atividade antimal?rica in vitro, com redu??o da parasitemia de 70,54 e 54%, respectivamente. Os extratos das tr?s algas testadas mostraram citotoxicidade moderada a elevada. As algas S. schroederi e U. flabellum foram ativas contra o P. berghei apenas nas doses de 500 mg/kg com redu??o variando de 54,58 a 52,65% para o quinto dia e 32,24 a 47,34% para o s?timo dia, respectivamente. N?o foi observada toxicidade in vivo para a dose testada, durante os 8 dias de observa??o. Embora sejam dados preliminares, os poss?veis componentes bioativos presentes nessas algas marinhas podem ser promissores para o desenvolvimento de novas drogas antimal?ricas
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Sorolla, Bardají Maria Alba. "Anàlisi proteòmica i estudi de marcadors d'estrés oxidatiu en la malaltia de Huntington." Doctoral thesis, Universitat de Lleida, 2011. http://hdl.handle.net/10803/32008.
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Carpinter, Bárbara Albuquerque. "Indução de imunidade com extrato proteico de Plasmodium berghei NK65 contra o desenvolvimento de malária cerebral por Plasmodium berghei ANKA em modelo murino." Universidade Federal de Juiz de Fora (UFJF), 2018. https://repositorio.ufjf.br/jspui/handle/ufjf/7782.
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Devido à ampla distribuição da malária entre os continentes e ao elevado número de casos clínicos e óbitos registrados anualmente, o desenvolvimento de uma vacina antimalárica segura e eficaz contra a doença ainda é de extrema importância. Dentre os vários modelos propostos até o momento, aquelas compostas por parasitos vivos ou por extrato proteico têm sido as mais promissoras no desenvolvimento de imunidade antimalárica. Entretanto, ainda não claro se imunizações com cepas com baixo potencial de virulência seriam capazes de prevenir ou amenizar os sintomas associados à malária grave. Assim, o presente estudo teve como objetivo investigar se camundongos imunizados com extrato proteico de Plasmodium berghei NK65, cepa de baixa virulência e não indutora de malária cerebral nesse modelo, são protegidos contra o desenvolvimento de malária cerebral induzida pela cepa ANKA de Plasmodium berghei (PbA). Para isto, foram realizados dois ciclos de imunização utilizando extrato proteico de Plasmodium berghei associado ao adjuvante CPG-ODN, com intervalo de 21 dias, em camundongos fêmeas C57BL/6, com idade entre 6 e 8 semanas. Após 30 dias da última imunização foi realizado o desafio experimental utilizando a cepa ANKA de P. berghei e iniciado o acompanhamento diário dos animais para avaliação do seu quadro clínico e da carga parasitária. Diante da presença de sinais neurológicos (escore clínico < 5), os animais foram pesados e eutanasiados para realização da coleta de sangue, baço e cérebro, enquanto animais sem esses sinais continuaram por ser acompanhados diariamente e, então, sacrificados a partir do 13º dia. A partir das amostras coletadas, foram determinados os níveis de anticorpos sorológicos, a frequência da população celular esplênica (células T CD4+ e CD8+, e linfócitos B), níveis de citocinas teciduais e análise histopatológica do tecido nervoso. Observouse que 46% dos animais imunizados com extrato de PbN e 69% dos animais imunizados com extrato de PbA foram protegidos do desenvolvimento de malária cerebral e tiveram sua taxa de sobrevivência prolongada, entretanto, estes animais desenvolveram hiperparasitemia sanguínea, com níveis de até 38% de parasitos circulantes. Estes animais não apresentaram sinais clínicos neurológicos, o que foi confirmado macroscopicamente pela ausência de hemorragia e reduzida inflamação no cérebro em relação aos animais que evoluíram para malária cerebral. Histopatologicamente, os animais com hiperparasitemia apresentaram poucos leucócitos aderidos ao endotélio vascular e ausência de vasos obstruídos. Em relação aos níveis de citocinas (IL-10, TNF-α, IFN-) e número de linfócitos esplênicos (T CD4+ e CD8+, e linfócitos B), estes estiveram significativamente reduzidos nos animais que desenvolveram hiperparasitemia em relação aos que desenvolveram malária cerebral. Interessantemente, os animais imunizados foram capazes de reconhecer tanto antígenos homólogos quanto heterólogos ao utilizado durante o processo de imunização, porém, esses anticorpos pareceram não influenciar o padrão clínico apresentado pelos animais. Portanto, nosso estudo demonstra que imunizações com parasitos de baixa virulência podem induzir imunidade capaz de proteger contra cepas altamente virulentas, mas os fatores que medeiam essa proteção ainda precisam ser melhor investigados.
The broad distribution of malaria around of the globe and the large number of clinical cases/deaths attributed to this disease turns the discovery of a safe and effective malaria vaccine an essential tool to halt the spread of the disease. Vaccines focused on the use of live parasites and crude parasites antigens have shown good results on the induction of antimalarial immunity, although it is still not clear if immunizations with low virulent strains are capable to prevent the development of symptoms of cerebral malaria. This research aim to investigate if immunizations with crude antigen of Plasmodium berghei NK65 (PbN), a low virulence strain noninductive of cerebral malaria in C57BL/6 mice, are able to protect the animals against the development of cerebral malaria after challenge with Plasmodium berghei ANKA (PbA). Mice were immunized twice with crude antigen associated to CPG-ODN adjuvant. Thirty days after the second immunization animals were challenged with 105 red blood cells infected with P. berghei ANKA. Animals were daily monitored to evaluate the clinical score and parasitaemia levels. If the presence of neurological signs (score < 5) were detected, animals were euthanized and blood samples, spleen and brain were collected; animals without neurological commitment were followed daily until the 14 day post-infection. Antibodies and cytokines levels, splenic cellular population (T CD4+, T CD8+ and B lymphocytes) and histopathological analysis were performed. The results showed that 46% of the animals immunized with crude antigen of PbN and 69% of the animals immunized with crude antigen of PbA were protected from the development of cerebral malaria and had their survival rate prolonged, however, these animals developed hyperparasitaemia, with levels up to 38% of circulating parasites. These animals did not present neurological signs which were confirmed macroscopically by the absence of hemorrhage and reduce brain inflammation in relation to the animals that evolved to cerebral malaria. Histopathologically, the animals with hyperparasitaemia presented few adhered leukocytes in the vascular endothelium and absence of obstructed vessels. In relation to cytokine levels and number of splenic lymphocytes, these were significantly reduced in animals that developed hyperparasitism in comparison with those who developed cerebral malaria. Interestingly, the immunized animals were able to recognize both homologous and heterologous antigens used during the immunization process, however, these antibodies did not appear to influence at the clinical condition presented by the animals. Therefore, our study demonstrates that immunizations with low virulence parasites may induce immunity capable of protecting against highly virulent strains, but the factors that mediate this protection still need to be better investigated.
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Esteban, Conde Gerard. "Biological assessment of novel series of Multitarget-Directed Ligands based on donepezil to be used in Alzheimer’s disease therapy." Doctoral thesis, Universitat Autònoma de Barcelona, 2015. http://hdl.handle.net/10803/381079.
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En l’actualitat, el tractament de la malaltia d’Alzheimer es basa principalment en l’ús d’inhibidors de colinesterases, els quals, juntament amb un antagonista de receptor NMDA han estat aprovats per la FDA. Tanmateix, l’ús d’aquests fàrmacs no només ha resultat terapèuticament ineficaç, sinó que a més el benefici simptomàtic que aquests compostos produeixen és temporalment. En el context d’una malaltia multifactorial com l’Alzheimer, la recerca de nous fàrmacs capaços de produir un efecte modulador de llarga durada és urgentment necessària.
Una de les aproximacions farmacològiques més acceptades recentment pel tractament de l’Alzheimer és l’ús dels lligands dirigits multidiana o MTDL. Aquests compostos multifuncionals són capaços de presentar diverses activitats farmacològiques amb la finalitat d’actuar simultàniament sobre diferents dianes terapèutiques.
En aquesta tesi s’ha realitzat l’estudi i avaluació del compost ASS234 i de diverses sèries de compostos MTDL de nova síntesi derivats del donepezil com a agents potencialment actius en la teràpia d’Alzheimer. Primerament, l’estudi s’ha dirigit en la millora de la caracterització del compost ASS234, un MTDL àmpliament descrit pel nostre grup com a agent amb diverses propietats que incluen una potent capacitat inhibitòria de les activitats MAO i ChE, un efecte neuroprotector i antiagregant de la proteïna beta amiloide in vitro i in vivo i una activitat antioxidant i antiapoptòtica. S’ha dut a terme la caracterització el mecanisme i cinètica del compost ASS234 com a inhibidor de les MAO i s’ha estudiat mitjançant HPLC el seu efecte modulador en el sistema monoaminèrgic en cultius cel·lulars i per microdiàlisi i UHPLC en rates tractades amb una única dosi d’aquesta molècula. Seguidament, compostos derivats de l’ASS234, com a híbrids de donepzil i propargilamines, han estat evaluats farmacològicament com a molècules potencials per l’Alzheimer. D’entre aquests compostos, s’han identificat potents inhibidors (en rang nanomolar) duals de les MAO i colinesterases com a estructures útils per al disseny i síntesi de futurs derivats millorats.
Finalment, s’ha seleccionat el compost DPH-4, d’entre una nova sèrie de compostos MTDL amb activitat quelant de metalls. Amb aquesta molècula s’han identificat múltiples propietats d’interés farmacològic en l’Alzheimer incloent una capacitat d’inhibició equimolar de les activitats MAO i ChE, un potent efecte quelant per complexar coure, ferro i zinc, una habilitat per restablir dels dèficits cognitius en rates tractades amb escopolamina, i efectes antioxidants, antiagregants de proteïna beta amiloide i antiinflamatoris in vitro.
En general, els resultats d’aquesta tesi reafirmen els potencials beneficis en l’ús farmacològic dels MTDLs en la teràpia d’Alzheimer, i proposen la molècula DPH-4 com a lead d’especial interés pel seu ús contra aquest transtorn neurològic.The current treatment of Alzheimer’s disease is essentially based on the use of cholinesterase inhibitors that together with a NMDA receptor antagonist have been approved by the FDA. Nevertheless, the use of these drugs in therapy has been reported ineffective accompanied with temporary sympomatic benefits. In the context of a multifactorial disorder such as Alzheimer’s disease, the search for new pharamacological approaches able to produce real long-term modulator effects is urgently encouraged. A well-accepted recent pharmacological approach for the treatment of Alzheimer’s disease is the so-called Multi-target directed ligards or MTDLs, as multifunctional compounds exhibiting multiple pharmacological activites to simultaneously interact with several therapeutic targets. In this thesis, the study and evaluation of compound ASS234 and other series of novel donepezil-derived MTDLs has been carried out as potentially active ligands for use in Alzheimer’s disease. First, a study focused on the improvement of the biochemical characterisation of compound ASS234 has been undertaken. This widely described MTDL by our group is a molecule bearing multiple properties including potent dual MAO and ChE inhibition, neuroprotective and anti-Aβ aggregating effect in vivo and in vitro and antioxidant and anti-apoptotic capacities. With ASS234, the mechanism and kinetics as MAO inhibitor was studied and its modulator effect on the monoaminergic system in both cell culture by HPLC and in vivo by microdialysis and UHPC was also assessed. Subsequently, novel ASS234-derived compounds as donepezil and propargylamine hybrids, were pharmacologically evaluated as potential drugs for potential use in Alzheimer’s disease therapy. Among the tested compunds, some potent dual MAO/ChE inhibitors were identified (nanomolar range) as scaffolds for further design a synthesis of new derivatives. Finally, compound DPH-4 was selected among a new series of MTDLs with metal-chelating properties. Multiple interesting activites were identified with this molecule for use in Alzheimer’s disease including a moderate equimolar capacity to dually inhibiting MAO/ChE activities, an ability to complex metals copper, iron and zinc, an effect to restore the cognitive deficits in scopolamine-treated rats and antioxidant, anti-Aβ aggreganting and anti-inflammatory properties in vitro. Overall, the results obtained in this thesis reinforce the potential pharmacological benefits of MTDLs for use in Alzheimer’s disease and suggest molecule DPH-4 as a lead compound for the treatment of this neurologic disorder.
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Mellhorn, Malin. "Water hyacinths (Eichornia crassipes) and their presence in Shire River, Malawi : Problems caused by them and ways of utilise them elsewhere." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-211625.
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Malawi is one of many countries throughout the world struggling with massive amounts of water hyacinths (Eichornia crassipes) in the country’s fresh water resources. In nutrient-rich ecosystems where the aquatic weed has no natural enemies it will reproduce very rapidly with the consequence that lakes become overgrown, water flow in rivers is reduced, and other water organisms becomes excluded. At the same time, the plants form a good breeding place for species carrying tropical diseases for example Malaria and Bilharzia. Water hyacinths are usually more of a problem for poorer countries since there are often great economic losses caused by the weed and to control their relative abundance is costly. In Malawi, 99 % of the produced electricity is based on water resources, mainly through hydropower turbines in the main river, Shire River. Water hyacinths, aggregated as islands, floating along the river and clogging the turbines cause repeated electricity black-outs and approximately 140 megawatt power is lost every day. To counter the weed interference with the electricity supply, there are great amounts of water hyacinths harvested every day and dumped along the road, with no further disposal plan. In this report, soil from one local dumping area is analysed to determine if such places are leaching nutrients or metals to the surrounding environment. Water hyacinths contain naturally high values of nutrients and farmers use these harvested plants as a green manure to improve soil properties on agricultural land. This paper aims to examine levels of metal in water hyacinths used as green manure. This is of interest since water hyacinths have the ability to effectively absorb substances from the water body which could pose a risk for potentially toxic elements (PTEs) to accumulate in the agricultural soil and subsequently in crops. Sampling and analyses were carried out with standard methods. Metal and nutrient levels in the analysed samples were obtained through detection with atomic absorption spectrophotometry (AAS), ion chromatography (IC) and UV/VIS spectrophotometry at the Department of Chemistry of Chancellor College in Zomba, Malawi. None of the investigated metal ions (Cr, Pb, Cd) were found in the analysed water hyacinths and since soil sampling was done during the dry season this thesis cannot determine if the dumping areas are leaching nutrients. Relatively high amounts of total phosphorus were found in the plants. Overall, the conclusion is that there is no risk of using water hyacinths harvested in Shire River as a green manure on agricultural land.
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Rodrigues, Regiane da Silva. "Avaliação de parâmetros fisiológicos e hemoparasitólogicos de Columbina talpacoti (Aves: Columbiformes): um estudo comparativo nos ambientes urbano e natural." Universidade Federal de Uberlândia, 2017. http://dx.doi.org/10.14393/ufu.di.2018.80.
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CNPq - Conselho Nacional de Desenvolvimento Científico e TecnológicoA urbanização determina fortes pressões sobre as populações naturais. A riqueza e a abundância de espécies mais sensíveis à urbanização diminuem, enquanto espécies generalistas e/ou oportunistas tendem a se tornar mais comuns, gerando um processo de homogeneização biótica. Outra mudança importante é representada pelo aumento de níveis de transmissão de parasitos, aspecto que vem sendo investigado, principalmente entre aves. Nesse sentido, o objetivo deste estudo foi avaliar se os indivíduos de Columbina talpacoti respondem de formas diferentes em relação aos ambientes naturais e ambientes urbanizados através da análise de índices hematológicos (razão heterófilos/linfócitos e leucócitos globais), parasitológicos (prevalência e parasitemia de hemoparasitos causadores da malária aviária) e índice de condição corporal. O estudo foi realizado no município de Uberlândia (MG). Foram estabelecidos 4 pontos de coleta dentro da cidade e 7 pontos de coleta na Reserva particular do Clube Caça e Pesca Itororó de Uberlândia. As capturas foram realizadas de março/2016 à outubro/2016, com redes de neblina. As aves foram capturadas e submetidas a procedimentos de coleta de sangue e medições biológicas. A coleta do sangue foi realizada através de venopunção braquial, com uma gota de sangue não heparinizado foi confeccionado o esfregaço sanguíneo, duas gotas de sangue foram acondicionadas em álcool absoluto em microtubos para posterior extração do DNA e investigação de haemosporídeos por PCR. A análise dos dados foi realizada através do teste-t e U-Mann-Whitney para verificar a existência de diferenças significativas entre os parâmetros analisados entre áreas urbanas e naturais. Para avaliar se há correlação nos parâmetros avaliados, os dados foram submetidos a correlação de Pearson e de Spearmann. Apenas a razão de heterófilos/linfócitos, que indica estresse, foi maior para área urbana do que na natural (t=3,673; p<0,05), os demais índices avaliados não apresentaram diferenças significativas. Também não foram observadas diferenças significativas entre os parâmetros avaliados com o sexo. O teste de correlação mostrou que apenas o índice de H/L relacionou-se positivamente com os leucócitos totais (rs=0.394; p<0,05), os demais itens não apresentaram correlação entre si. Estes resultados indicam que os animais estão mais estressados no ambiente urbano, mas que com a disponibilidade alta de recursos alimentares em conjunto com a plasticidade fenotípica dos indivíduos, a condição corporal não se altera em nenhuma das áreas. Além disso, como as infecções avaliadas estão em estágio crônico, os sintomas da doença são brandos e quase inexistentes.
Urbanization creates strong pressures on natural populations. Both richness and abundance of more susceptible species diminish due to urbanization, while generalized and / or opportunistic species tend to become more common, leading to a process known as biotic homogenization. Another important contribution of Urbanization is represented by the increasing rates in parasite transmission, mainly among birds. In this sense, the main purpose of this study was to evaluate how individuals of Columbina talpacoti respond in different special gradients: natural and urbanized environments. Three indices were analyzed: hematological, parasitological (avian malaria prevalence and parasitemia) and body condition. The study was carried out in the city of Uberlândia (MG). There were 4 collection points within the city and 7 collection points in the Clube de Caça e Pesca Itororó de Uberlândia. Captures were carried out from March 2016 to October 2016, by using mist nets, and collecting a blood sample and morphometric measurements from each individual. Blood collection was done through a venipuncture, getting a drop of non-heparinized blood to make three blood smears. Two blood drops were conditioned in absolute alcohol in microtubes for later DNA extraction and PCR procedures. Data analysis was performed using Mann-Whitney test to verify the existence of significant differences between the patterns analyzed between urban and natural areas. The data was submitted to both Pearson and Spearmann correlation test to check for possible correlation among the variables. Only one hematological index (heterophilic / lymphocyte ratio), which indicates stress, was higher for the urban than natural area (t = 3.673, p <0.05). The other indices were not statistically significant. There were also no significant differences between sex identities as well. Only the H/L index was positively related to the total leukocytes (rs = 0.394, p <0.05), shown by the correlation tests. These results indicate that animals are more stressed in the urban environment. Having high food availability coupled with a phenotypic plasticity of individuals, body condition did not change in any of the areas. In addition, since the infections evaluated are in the chronic stage, the symptoms of the disease are mild and almost non-existent.
Dissertação (Mestrado)
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Castineiras, Catarina Maria dos Santos. "Recombinação ectópica e redistribuição do conteúdo de genes variantes em amostras de campo de Plasmodium falciparum." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/42/42135/tde-16082011-145442/.
Full textAbstract:
Entre cepas diferentes de P. falciparum existe uma grande variação entre as sequências das famílias de genes variantes. Um motivo para esta grande variedade é o fato que a maioria dos genes variantes se encontra em regiões subteloméricas e que o parasita é capaz de recombinar telômeros heterólogos durante a meiose (recombinação ectópica), levando a uma nova distribuição e a criação de novos genes variantes. Além desse fenômeno que ocorre durante a fase sexual do parasita, foi considerado que recombinações também podem ocorrer durante a fase mitótica na fase assexuada sanguínea. Neste estudo, procuramos monitorar a importância desta recombinação ectópica na geração de novos genes var em amostras de campo da Amazônia brasileira. Em experimentos paralelos elucidamos se existe recombinação ectópica também durante divisões puramente mitóticas. Observamos que muitos genes var que são compartilhados entre isolados mudam raramente ou não mudam de posição cromossômica. Observamos que no caso de mudança de posição cromossômica muitas vezes ocorreu duplicação do lócus. Muitos dos genes var compartilhados se encontraram em cromossomos 5-6 e 9-7. Por monitoramento de clones de 3D7 após 180 gerações não observamos nenhuma translocação de genes var subtelomérico ou telomérico indicando que a recombinação ectópica em mitoses é de fato um evento raro.Different strains of the causative agent of malaria, Plasmodium falciparum, possess greatly varying repertoires of variant antigen encoding gene families. One reason for this variety lies in the fact that most of the variant gene families are found in subtelomeric regions. The parasite is able to recombine heterologous telomers during meiosis through a process coined ectopic recombination, potentially leading to a new distribution and creation of variant genes. Due to morphological similarities of chromosome end clustering in sexual as well as in asexual forms, it was hypothesized that ectopic recombination may also occur in mitotic asexual blood stage parasites. Herein we monitor the occurrence of ectopic recombination in field samples from the Brazilian Amazon. In parallel, we elucidated whether ectopic recombination also takes place in purely mitotic divisions. We observed that many var genes which are shared among isolates rarely change their chromosomal position. When a change occurred, we often observed chromosomal locus duplication and many of the shared genes were found on chromosomes 5-9 or 5-10. After outgrowth of the 3D7 strain for 200 generations with intermittent cloning we did not observe any translocation of telomeric or subtelomeric var genes, indicating that ectopic recombination in mitosis is a rare event.
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Fratus, Alessandra Sampaio Bassi. "Casos assintomáticos de malária na Amazônia Brasileira: citoaderência, anticorpos contra a superfície da hemácia infectada e proteção em infecções naturais por Plasmodium falciparum." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/42/42135/tde-19092012-105336/.
Full textAbstract:
Um importante fator na virulência do P. falciparum é sua capacidade de aderência a receptores endoteliais, mediada por proteínas PfEMP1. No Brasil, o número de variantes PfEMP1 é limitado, com raras evoluções graves da doença, e presença de indivíduos portadores do parasita e sem sintomas. Localizamos anticorpos contra a membrana do eritrócito infectado em plasmas de indivíduos de Rondônia; sem diferenças na resposta imune nos dois grupos (selecionados tanto para ICAM1 quanto CD36), tanto em frequência quanto em; encontramos diferenças significativas em capacidade de inibição de citoadência apenas em casos pontuais, sem correlação com índice de reatividade ou fenótipo; observamos presença de anticorpos pan-reativos, capazes de aglutinar diferentes isolados, porém sem diferenças entre os isolados selecionados para ICAM1 e CD36. Os dados indicam que a resposta contra a superfície da hemácia infectada - ao menos dos isolados e fenótipos testados neste trabalho - não parece ser um critério decisivo para o tipo de evolução de malaria sofrida pelo paciente.An important factor in P. falciparum\'s virulence is its ability to adhere to endothelial receptors, mediated by PfEMP1 proteins. In Brazil the number of PfEMP1 variants is limited, severe disease is rare, and there are many individuals carrying the parasite without symptoms. We detected antibodies against the membrane of erythrocytes using plasma of infected individuals from Rondônia, finding only in some cases differences in the immune response, both in frequency and degree; we also could not find differences between the ability to inhibit cytoadherence in static condition. There was no correlation between this capacity and the reactivity index or phenotype; we observed the presence of pan-reactive antibodies that were capable of agglutinating different isolates, but without any difference between ICAM1 and CD36 selected isolates. Taken together, our data indicate the immune response against the infected red blood cell is not decisive for the outcome of malaria suffered by the patients.
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Sànchez, Ollé Gessamí. "Aproximació terapèutica per a la malaltia de Gaucher basada en xaperones." Doctoral thesis, Universitat de Barcelona, 2011. http://hdl.handle.net/10803/94202.
Full textAbstract:
En aquesta tesi s’ha realitzat una aproximació terapèutica per a la malaltia de Gaucher, basada en xaperones farmacològiques.
La malaltia de Gaucher és una malaltia d’acúmul lisosòmic d'herència autosòmica recessiva, causada per mutacions en el gen GBA, o en alguns pocs casos, per mutacions en el gen PSAP. El gen GBA codifica la hidrolasa lisosòmica glucocerebrosidasa i el gen PSAP codifica la proteïna activadora de l'enzim anterior, la Saposina C.
Fins al moment s'han descrit més de 300 mutacions en el gen GBA causants de la malaltia de Gaucher, que han permès desenvolupar un diagnòstic molecular de la malaltia, i unes poques en el gen PSAP. Aquestes mutacions produeixen una deficiència en alguna d'aquestes dues proteïnes, la glucocerebrosidasa o la Saposina C, que estan implicades en la via de degradació dels glicoesfingolípids.
La manca d’una bona correlació genotip-fenotip fa que els estudis d’expressió puguin aprofundir en el coneixement sobre la fisiopatologia de la malaltia de Gaucher. En aquest treball presentem els estudis cel•lulars que han permès expressar els al•lels mutats en cèl•lules COS així com establir l’origen de l’al•lel doble D409H;H255Q. A més a més, hem confirmat l’efecte negatiu acumulatiu d’aquestes dues mutacions a nivell d’activitat enzimàtica, gràcies a l’expressió heteròloga dels al•lels únics i doble mutant.
Una de les teràpies que actualment s'està utlitzant en la malaltia de Gaucher és la teràpia de reducció de substrat com a complement o alternativa a la teràpia de reemplaçament enzimàtic. En els darrers anys, una nova estratègia terapèutica basada en l’ús de xaperones farmacològiques ha aparegut. Aquesta nova aproximació es basa en la hipòtesi que les xaperones farmacològiques impedeixen que els enzims amb mutacions que impedeixen el bon plegament podien estabilitzar-se i arribar a seu destí, el lisosoma.
Els dos objectius principals han estat:
1. L’expressió in vitro, mitjançant cèl•lules COS-7, de diversos al•lels mutats del gen GBA i la caracterització de les proteïnes GBA mutades.
2. Assajar l’efecte dels iminosucres (NN-DNJ i NB-DNJ), aminociclitols i dels seus derivats com a possibles xaperones farmacològiques sobre les proteïnesmutades, tant en cèl•lules COS-7 transfectades amb cDNAs mutats com en fibroblasts de pacients.
Els resultats s’han presentat en els articles següents:
1. Homozygosity for the double D409H+H255Q allele in type II Gaucher disease
Autors: Helen Michelakakis, Marina Moraitou, Evagelia Dimitriou, Raül Santamaria,
Gessamí Sànchez, Laura Gort, Amparo Chabás, Daniel Grinberg, Maria Dassopoulou,
Spyros Fotopoulos, Lluïsa Vilageliu.
Publicació: Journal of Inherited and Metabolic Diseases (2006) 29:591
2. Haplotype Analysis Suggests a Single Balkan Origin for the Gaucher Disease [D409H;H255Q] Double Mutant Allele
Autors: Raül Santamaria, Helen Michelakakis, Marina Moraitou, Evangelia
Dimitriou, Silvia Dominissini, Serena Grossi, Gessamí Sánchez-Ollé, Amparo
Chabás, María Gabriela Pittis, Mirella Filocamo, Lluïsa Vilageliu, Daniel Grinberg
Publicació: HUMAN MUTATION Mutation in Brief #1010, 29:E58-E67, 2008
3. Promising results of the chaperone effect caused by imino sugars and
aminocyclitol derivatives on mutant glucocerebrosidases causing Gaucher disease.
Autors: Gessamí Sánchez-Ollé, Joana Duque, Meritxell Egido-Gabás, Josefina
Casas, Montserrat Lluch, Amparo Chabás, Daniel Grinberg, Lluïsa Vilageliu
Publicació: Blood Cells, Molecules, and Diseases 42 (2009) 159–166
4. Chaperone effects caused by new aminocyclitol derivatives on mutant
glucocerebrosidases causing Gaucher disease.
Autors: Lucía Díaz, Gessamí Sánchez-Ollé, Josefina Casas, Daniel Grinberg,
Antonio Delgado and Lluïsa Vilageliu
Publicació: In press.
Les dades recents presentades fan pensar que les xaperones farmacològiques podrien arribar a ser un tractament tant per les formes no neuronopàtiques com per a les neuronopàtiques de la malaltia de Gaucher.Lysosomal storage diseases are a group of disorders caused by the loss of function of lysosomal enzymes, which leads to the intralysosomal storage of non-degraded substrates. Gaucher disease (GD, OMIM 230800) is the most prevalent sphingolipidosis caused by deficiency of glucocerebrosidase (GBA, E.C. 3.2.1.45), which produces the progressive accumulation of glucosylceramide. Clinically, GD is classified into three major types depending on the absence (Type I) or presence (Type II and III) of central nervous system involvement. The main symptoms of GD are anaemia, thrombocytopenia, hepatosplenomegaly and skeletal disease. Two disease-specific therapies have been approved to treat GD. Enzyme replacement therapy (ERT) has been applied for more than 15 years and has proved successful mainly for symptoms of type I patients. The other approved treatment is substrate reduction therapy, which is based on the inhibition of glucosylceramide synthase (GCS), the rate-limiting first step in the glycosphingolipid biosynthetic pathway, by the oral administration of N-butyl-deoxynojirimycin (NB-DNJ). This reduction therapy is used for type I patients for whom ERT is not a therapeutic option. The small size of NB-DNJ makes it of potential use for neurological cases. To date, other alternative strategies, such as gene therapy, have had very limited success in the treatment of GD. However, new experimental approaches in cellular and animal models have been assayed either for conventional gene therapy or based on the partial inhibition of the GCS gene using siRNAs. Recently, a new line of research, using small molecules that act as chemical chaperones, has emerged. This approach is based on the assumption that some mutations cause the misfolding of lysosomal enzymes after their synthesis. Misfolding is responsible for enzyme degradation in the endoplasmic reticulum (ER), thereby preventing enzyme transport to the lysosome. In this scenario, the chaperone stabilizes the mutant protein, thereby allowing that, at least, some molecules reach their final destination. Here we analyzed the effect of iminosugars NB-DNJ and NN-DNJ and aminocyclitols, on COS cells transfected with either the wild-type or mutant GBA cDNAs. The effect of these compounds was also tested on the residual β-glucosidase activity of fibroblasts from patients with diverse genotypes.