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1
Nichol, Claire Patricia. "Host-parasite interactions of larval cestode infections." Thesis, University of Edinburgh, 1985. http://hdl.handle.net/1842/30579.
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Anderson, J. J. "The immune response to respiratory syncytial virus in an animal model." Thesis, University of Newcastle Upon Tyne, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380769.
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Snart, Charles J. P. "The metabolomics of host-parasitoid interactions." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/30607/.
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This thesis examines the relationship between insect life history and behavioural decisions and underlying cellular biochemistry, with particular focus on bethylid parasitoid wasps in the genus Goniozus. This comprises the first major body of work attempting to draw links between the underlying metabolome of an organism and its behaviour. This thesis further optimised the first known example of a combined LC-MS and NMR metabolomic approach capable of analysing extremely low biomass samples (<1 mg), a vital requirement when studying the behaviour of individual organisms. Part 1 of this thesis details the optimisation and validation of this metabolomic approach, whilst also examining the effects of aging on the metabolome of adult Goniozus wasps. Part 2 applies this approach to examine the effects of diet, host species and host aging on Goniozus wasp behaviour and biochemistry. Comparisons of the metabolomes of starved and honey fed wasps indicate that G. legneri is capable of utilising a carbohydrate rich diet as an energy source. Aged honey fed wasps possessed higher levels of large storage lipids, such as tri- and diacylglycerides, than starved wasps of the same age. Metabolomic analysis also detected a legacy effect on the metabolome of G. legneri associated with differences in the species of host each wasp was reared on. A similar legacy effect was confirmed when examining the metabolomes of wasps reared on artificially aged hosts. Whilst Goniozus wasp oviposition behaviour was altered by the species of host presented, no links between changes in a wasp’s metabolome and its resulting contest behaviour were found. Part 3 of this thesis examines the morphological, behavioural and chemical mimicry of another wasp, the hyperparasitoid Gelis agilis. G. agilis demonstrated an enhanced predation avoidance rate compared with control species, similar to that of the black garden ant Lasius niger. Agitation of G. agilis also resulted in the chemical emission of a known ant alarm pheromone.
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Hope, Andrew. "Host location and selection by British Culicoides species associated with farms." Thesis, University of Liverpool, 2013. http://livrepository.liverpool.ac.uk/16273/.
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Culicoides biting midges (Diptera: Ceratopogonidae) are biological vectors of economically important arboviruses of livestock. Two such arboviruses, bluetongue virus (BTV) and Schmallenberg virus (SBV) have recently emerged in northern Europe inflicting unprecedented outbreaks of disease in this region. The aim of the current investigation was to explore both host seeking behaviour and surveillance methods for livestock-associated Culicoides species in the UK. To achieve this aim, a series of field-based, manipulative experiments were conducted using three farm sites in southern England. These studies demonstrated that host preference had a significant impact upon several parameters important in determining arbovirus transmission. Culicoides were found to be differentially attracted to different breeds of sheep (p<0.05) and blood feeding efficiency was shown to be determined in part by whether the sheep had been sheared (p<0.05). In addition the presence of an alternative host (a cow and its calf) was demonstrated to lead to an increased Culicoides biting rate on sheep held in close proximity (p<0.05), increasing the risk of arbovirus transmission. Preliminary studies of volatile chemicals produced by hosts illustrated that while these attracted livestock-associated Culicoides at rates higher than those recorded in un-baited traps (p<0.05), collections only represented a small proportion of those collected on hosts themselves. These studies, however, provided a platform for future investigations of this area. Finally, the use of light-emitting diode (LED) baited suction traps was trialled as a means of improving detection sensitivity in surveillance of Culicoides populations. This study found that certain Culicoides species demonstrated increased sensitivity to specific wavelengths (p<0.05) and integration of these commercially available traps could improve our understanding of the abundance, geographic distribution and behaviour of these species.
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Ali, Ahmed A. "INTERSPECIES TRANSMISSION AND HOST RESTRICTION OF INFLUENZA A VIRUSES." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1354125078.
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Lejmi, Mrad Rim. "Pathological and genetic analysis of host susceptibility to cardiovirulent coxsackievirus B3 infection in mice." Thesis, University of Ottawa (Canada), 2005. http://hdl.handle.net/10393/26953.
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Nearly fifty percent of North American myocarditis cases are associated to coxsackievirus group B, type 3 (CVB3) infection. CVB3 infection of mice provides a useful model to study pathogenic mechanism of myocarditis. The objective of this study is to test the hypothesis that susceptibility, during the acute CVB3 infection, is under polygenic control including H2 as well as the non H-2 genes.
To identify differential parameters of the disease, and if they are influenced by the H-2 haplotype, several phenotypic traits were characterized. Three inbred strains of mice and two congenic strains were infected with CVB3. Differences in survival, body weight loss, quantification of myocarditis and quantification of sarcolemmal disruption were found by comparing three sets of mice sharing the same H-2 haplotype but not the same background. It was determined that host susceptibility to CVB3-induced myocarditis is mainly controlled by "background" genes.
Moreover, because there is a naturally occurring variability among inbred mice, ten inbred strains of mice were used for the genetic analysis of four CVB3-induced phenotypes: survival, body weight loss, heart viral load and quantification of sarcolemmal disruption. It was concluded that the strains could be divided into three groups: the highly resistant, the resistant to intermediate strains and the highly susceptible strains. This phenotypic data on commonly used and genetically diverse inbred mouse strains sets up the platform for a detailed analysis of the genetic basis of susceptibility to CVB3.
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Peres, Amos. "Effects of an interferon inducer, pI:C, on the graft-versus-host reaction." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74294.
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Polyinosinic: polycytidylic acid (pI:C), an interferon (IFN) inducer, was used to investigate the role of IFN in the graft-versus-host reaction (GVHR), induced by injecting parental cells into F1 recipients and assessed for immunosuppression and pathological lesions.<br>PI:C-treatment of recipients, but not donors, before GVHR-induction suppressed the GVHR, an effect seen only with C57BL/6 (B6) and not A donor cells. Using fluorescein-labelled donor cells, pI:C-treatment was seen to cause a marked decrease in donor cell survival after 2 days. Elimination of donor cells was specific for the B6 donor, was associated with increased natural killer (NK) cell but not macrophage cytotoxic activity, was radioresistant and anti-asialo GM1 sensitive, evidence supporting NK-mediated rejection.<br>Plotting donor cell recovery against the number of cells injected into variously treated recipients indicated that in unstimulated mice a constant proportion of the injected cells were rejected, pI:C increasing that proportion, suggesting that pI:C changes F1 NK target repertoire.<br>PI:C-treatment after GVHR-induction increased the severity of the GVHR, especially soon after GVHR-induction, the effect waning afterwards. No strain dependence was observed.<br>These results demonstrate that IFN/IFN-activated cells play an important role in the regulation and in the immunosuppression/pathogenesis of a GVHR.
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Buckingham, Erin M. "Studies of gammaherpesvirus infection and host response /." Connect to abstract via ProQuest. Full text is not available online, 2007.
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Foster, Rosalinda Gram. "Virus-Host Interactions in the Development of Avian Leukosis Virus-Induced Osteopetrosis: a Dissertation." eScholarship@UMMS, 1993. https://escholarship.umassmed.edu/gsbs_diss/180.
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Avian leukosis virus (ALV)-induced osteopetrosis is a proliferative disorder of the bone affecting the growth and differentiation of osteoblasts. Osteopetrosis is a polyclonal disease in which cells of the bone contain, on average, multiple viral DNA copies. Osteopetrotic bone is also characterized by the accumulation of unintegrated viral DNA, suggesting an atypical life cycle of the virus in the infected osteoblasts. To better understand virus-host interactions in the induction of osteopetrosis by ALVs, infected chick osteoblast cultures and osteopetrotic bone were examined for aspects of the virus life cycle and effects of infection on osteoblast function.
Levels of infection and virus expression were compared in cultured osteoblasts and osteopetrotic bone. Osteopetrotic bone contained higher levels of viral DNA and correspondingly higher levels of viral proteins than infected osteoblast cultures, suggesting a higher viral load in the diseased bone. A significant level of mature Gag protein was present in the bone, suggesting the accumulation of mature virus particles in the diseased bone. It is possible that the accumulation of virus could facilitate the high levels of infection observed in the diseased bone.
The mechanism by which unintegrated viral DNA persisted in osteopetrotic bone was investigated by examining the susceptibility of infected osteoblasts to superinfection. The results indicated that, in culture, infected osteoblasts were able to establish interference to superinfection. This suggests that the persistence of unintegrated viral DNA in osteopetrotic bone may not result from the continuing infection of productively infected osteoblasts.
The effect of virus infection on osteoblast function was examined in the diseased bone and in osteoblast cultures. In infected chickens, osteoblast activity, as evidenced by the expression of osteoblast phenotypic markers, was increased only in chickens developing severe osteopetrosis. In culture, virus infection had no apparent effect on either the proliferation or differentiation of osteoblasts. This indicates that infection was itself not sufficient to perturb osteoblast function. Furthermore, it suggested that additional components of the bone may be required for ALV infection to induce the abnormal activity of osteoblasts observed in osteopetrosis.
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Jones, Darbi Rae. "The Effect of Vaccination and Host Genetics on Transmission Dynamics of Infectious Hematopoietic Necrosis Virus and Flavobacterium Psychrophilum in Rainbow Trout (Oncorhynchus Mykiss)." W&M ScholarWorks, 2019. https://scholarworks.wm.edu/etd/1582642565.
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Globally, infectious diseases are responsible for major conservation and economic losses in wild and farmed fish populations. Prevention tools, including vaccination and breeding for genetic disease resistance, are used in many systems to prevent mortality by such diseases. Studies are often done to evaluate the efficacy of a preventative method at reducing disease, but the impact on transmission is rarely studied. Protection under diverse field conditions, such as variable pathogen exposure dosages, is also not fully understood. Furthermore, there is little information on how preventative methods alter host-pathogen relationships. For example, it is largely unknown how vaccination impacts non-target pathogens that co-infect the host. These knowledge gaps make it difficult to infer the epidemiological impacts of disease prevention tools. In an attempt to fill these gaps, we investigated two leading pathogens in rainbow trout (Oncorhynchus mykiss) aquaculture: infectious hematopoietic necrosis virus (IHNV) and Flavobacterium psychrophilum. We evaluated the impacts of vaccination and genetic disease resistance on mortality and transmission across a range of challenge dosages of IHNV and F. psychrophilum to accurately reflect field variability. There was evidence of a dosage effect; as dosage increased, shedding increased and vaccine efficacy decreased. We also evaluated how vaccination and genetic disease resistance impact transmission dynamics during simultaneous and sequential co-infection of IHNV and F. psychrophilum. Our results indicate co-infected fish shed more of both pathogens than they do in single infections, and the order that the pathogen infected the host may impact transmission in both pathogens. Furthermore, vaccine efficacy may be diminished by co-infection. These studies are aimed at developing a more robust framework for inferring the efficacy of disease prevention strategies. Our results will also help to inform and improve disease management in one of the top aquaculture species in the United States.
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Lopez-Arellano, Maria Eugenia. "The role of surface and secreted antigens in the host-parasite interaction of plant and animal nematodes." Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302321.
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Marjamaki, P. "The genetic basis of variation in bovine tuberculosis infection, progression and diagnosis in a wild animal host." Thesis, University of Exeter, 2019. http://hdl.handle.net/10871/36577.
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Parasites are ubiquitous in wild animal populations and have wide ranging effects on the health, fitness and eco-evolutionary dynamics of their host populations. To counter parasites, hosts have evolved a myriad of defence strategies, but individuals vary considerably in the efficacy of these strategies, and so, in their susceptibility to infection. While variation can generally be viewed as stemming from genetic and environmental effects, we currently have little knowledge of their relative importance in wild and unmanaged host populations. In this thesis, I use long-term mark-recapture data on a population of European badgers (Meles meles) to examine the genetic basis of variation in bovine tuberculosis infection and its progression. I first estimate a genetic pedigree and characterise variation in extra-group paternity in the population (Chapter 2). Then, adopting a pedigree-based quantitative genetic approach, I investigate the relative importance of genetic and social environmental sources of variation in bTB infection status (Chapter 3). Thirdly, I characterise associations between body weight and bTB infection and test for variation in host tolerance (Chapter 4). And finally, I examine the genetic basis of (co)variation in and among four diagnostic test responses, representing different aspects of host immune function (Chapter 5). Taken together, this work provides novel insight into the genetic architecture of bovine tuberculosis infection in a wild host species, and the evolutionary potential of immune traits in the wild.
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Bruce, Toby Johann. "The olfactory basis for attraction of the bollworm Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) to host-plant flowers." Thesis, University of Greenwich, 2000. http://gala.gre.ac.uk/8306/.
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The objective of this work was to investigate whether or not olfactory clues play a role in host plant location by the polyphagous moth, Helicoverpa armigera. Volatiles collected from flowers of African marigold, Tagetes erecta, and sweet pea, Lathyrus odouratus, were found to elicit electroantennographic (EAG) responses from the antennae of female H. armigera. Compounds active in GC-EAG analyses of T. erecta floral headspace samples, identified by GC-MS and comparison of retention times on polar and non-polar GC columns with authentic standards, were (E)-myroxide, benzaldehyde, (f)-linalool, phenylacetaldehyde and (-)- piperitone. EAG-active compounds in L. odouratus floral headspace samples were identified as diacetone, (-)-linalool, phenylacetaldehdyde and benzyl alcohol. Increases in upwind flight to air entrained extracts of floral odours indicated that these cues caused attraction when presented to female H. armigera. A synthetic T. erecta blend comprising benzaldehyde, (f)- linalool, phenylacetaldehyde and (+)-limonene gave significant increases in upwind flight approaches. Limonene (either (+)- or (-)-) was found to be important for the behavioural response despite having low EAG-activity. There was no significant difference in upwind flight response to odours from the live flower and the synthetic floral blend. Significant increases in upwind flight were also obtained when insects were presented with a synthetic L. odouratus blend which contained the four EAG-active compounds identified from GCEAG studies. In field trapping experiments in Israel there was a significant difference in H. armigera catches in traps with a standard 4-component T. erecta lure compared with unbaited traps over the whole season. Mean H. armigera catch per trap per night (both sexes) over the whole season in unbaited traps, floral odour traps, pheromone traps and light traps were 0.004,0.11,8.8 and 1.35 respectively. The floral baited traps were non-selective catching large numbers of Ilymenoptera and Diptera as well as other moth species. Field trapping experiments in Pakistan indicated that the floral lure was significantly attractive to Earias spp. and other Lepidoptera although very few H. armigera were caught due to low population density. Olfactory cues are discussed in relation to host-plant finding behaviour of H. armigera. They are involved in early stages of host seeking behaviour prior to alighting on the plant and stimulate searching behaviour.
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Earnhart, Christopher G. "Dynamics of the host-parasite interaction: in vitro correlates of Crassostrea-induced modulation of Perkinsus marinus function." W&M ScholarWorks, 2004. https://scholarworks.wm.edu/etd/1539616637.
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Perkinsus marinus is an alveolate protozoan parasite of the eastern oyster (Crassostrea virginica) which is responsible for much of the decline in United States oyster populations. Perkinsus marinus can be cultured in vitro, but is rapidly attenuated in the process. Supplementation of a protein-free medium with oyster products altered proliferation, changed protease expression in the parasite extracellular products (ECP), induced morphological forms typically seen in vivo, and partially reversed parasite attenuation. Supplements derived from dissected oyster tissues were used to determine if these changes could be differentially elicited. These supplements, with the exception of adductor muscle, reduced proliferation. Whole oyster and digestive gland/gonad supplements favored palintomic, rather than binary, fission. The total ECP protease activity was generally decreased in supplemented cultures, though gill/mantle supplements may have induced proteases. A low molecular weight subset of proteases was upregulated most effectively by heart- and adductor muscle-derived supplements. Serine proteases and other ECP proteins may be virulence factors. Attempts to create antibodies to study P. marinus cells and ECP have been largely unsuccessful due to poor immune responses and crossreactivity. Ultrafiltration-concentrated P. marinus ECP were poorly immunogenic and toxic to experimental animals. Immunogenicity was not substantially affected by heat denaturation or proteolytic inhibition. Co-administration of ECP with oyster plasma caused a suppression in the anti-plasma antibody response with restriction of epitope recognition. Analysis of medium constituents revealed that a surfactant, Pluronic F-68 (PF68), was immunosuppressive. Although isolated protein antigens from the ECP remained immunosuppressive, separation of the antigens from PF68 enabled antibody production. Five monoclonal antibodies were created against ECP from unsupplemented medium and were used to study ECP function, regulation, and mechanism of storage and release. ECP are secreted by release from the cell wall and from two morphologically distinct intracellular compartments. A sandwich ELISA allowed quantification of an ECP protein with significantly reduced expression in supplemented cultures. Another antibody, which specifically bound to trophozoite and tomont walls, was used to investigate morphological and antigenic changes during thioglycollate-induced formation of prezoosporangia, and confirm supplement-induced formation of prezoosporangia. This antibody labeled P. marinus cells in fixed oyster tissue in a species-specific manner.
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La, Peyre Jerome F. "Studies on the oyster pathogen Perkinsus marinus (Apicomplexa): Interactions with host defenses of Crassostrea virginica and Crassostrea gigas, and in vitro propagation." W&M ScholarWorks, 1993. https://scholarworks.wm.edu/etd/1539616724.
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The disease caused by the protozoan Perkinsus marinus has been a major source of mortality in the eastern oyster, Crassostrea virginica. Variations in susceptibility to P. marinus infection among eastern oysters collected from the Chesapeake Bay and Gulf of Mexico, as well as between eastern and Pacific (Crassostrea gigas) oysters were determined. Since oyster host defense may play a role in determining susceptibility to pathogen infection, cellular and humoral defense activities of the oyster and their interactions with P. marinus were investigated. Procedures also had to be established to isolate, purify, and propagate in vitro, P. marinus. Eastern oysters from all sites were found to be highly susceptible to the pathogen. Cellular and humoral activities were significantly affected by heavy intensity of P. marinus infection. Prevalence and intensity of P. marinus infection were lower in Pacific oysters than in eastern oysters. Pacific oysters may offer a less favorable environment for the development of P. marinus compared to eastern oysters for at least two possible reasons: the elevated cellular and humoral activities may degrade the parasite more effectively, and lower plasma protein levels may limit parasite growth. Incubation of merozoites with hemocytes of eastern and Pacific oysters in vitro suggested that limited intracellular killing of P. marinus occurred but that killing was not mediated by oxygen metabolites. Perkinsus marinus was successfully propagated in vitro in a culture medium containing most of the known constituents of cell-free oyster hemolymph. Cultures of the parasite were initiated from heart fragments of infected oysters. The cultured protozoan was similar in morphology to P. marinus, enlarged in fluid thioglycollate medium, reacted with polyclonal antibodies raised against hypnospores and was infective. Continuous cultures of P. marinus could also be initiated from hypnospores. Two types of division, progressive cleavage and successive bipartition of the mother cell protoplast, were observed.
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Asensio, Grau Andrea. "In vitro approach of dietary and host related factors affecting digestion of animal-origin foods under cystic fibrosis disease." Doctoral thesis, Universitat Politècnica de València, 2021. http://hdl.handle.net/10251/171512.
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Tesis por compendio<br>[ES] De entre las metodologías disponibles para estudiar la digestión de alimentos, los modelos de digestión in vitro se plantean como procedimientos válidos para este propósito. La digestión in vitro consiste en simular el proceso de digestión en el laboratorio, reproduciendo las condiciones fisiológicas en cuanto a composición de los fluidos digestivos (electrolitos y enzimas), pH, temperatura, fuerzas mecánicas y duración de las etapas oral, gástrica e intestinal.
Abordar el estudio de la digestión de nutrientes es de especial relevancia en patologías que cursan con alteraciones pancreáticas o hepáticas, asociadas a una digestión de lípidos comprometida en la etapa intestinal, debido a la disminución de secreción de pancreatina, bicarbonato y sales biliares. Este es el caso de la fibrosis quística con insuficiencia pancreática, y los pacientes que padecen esta afección deben seguir la terapia de sustitución de enzimas pancreáticas, que consiste en el suministro exógeno de pancreatina encapsulada. Sin embargo, la dosis de este suplemento debe ajustarse a las características de los alimentos y no se dispone de ningún método válido para tal fin. Para hacer frente a este reto, en el proyecto financiado con fondos europeos MyCyFAPP se ha logrado desarrollar un método para ajustar la dosis óptima de los suplementos enzimáticos utilizados en la terapia. La presente tesis doctoral se realizó en el marco de dicho proyecto.
Concretamente, esta tesis tiene como objetivo abordar el estudio de la digestión de lípidos en los alimentos de origen animal (carne y productos cárnicos, huevos, queso y pescado) en el contexto de la fibrosis quística. Para abordar este objetivo se aplicó un modelo de digestión in vitro estático con el fin de explorar el papel de las características inherentes a los alimentos (estructura de la matriz alimentaria como resultado del procesado) y los factores relacionados con el individuo (pH, concentración de sales biliares y concentración de pancreatina) como factores determinantes de la lipólisis en alimentos de origen animal.
A lo largo de los cuatro capítulos presentados, centrados en el huevo, la carne, el queso y el pescado, se presenta un diseño experimental común para estudiar la lipólisis, la proteólisis y la degradación de la matriz. En cada estudio, las diferentes técnicas de procesado aplicadas a los alimentos evaluados también permitieron evaluar el efecto de las propiedades inherentes a los alimentos en los resultados del estudio. Los resultados han contribuido al desarrollo de un nuevo método basado en la evidencia para optimizar la terapia de reemplazo de enzimas pancreáticas e informan a la comunidad científica sobre nuevos conocimientos en el comportamiento de diferentes alimentos sometidos al proceso de digestión.<br>[CA] De les metodologies disponibles per estudiar la digestió d'aliments, els models de digestió in vitro es plantegen com a procediments vàlids per a aquest propòsit. La digestió in vitro consisteix en simular el procés de digestió al laboratori, reproduint les condicions fisiològiques pel que fa a la composició dels fluids digestius (electròlits i enzims), pH, temperatura, forces mecàniques i durada de les etapes oral, gàstrica i intestinal. Abordar l'estudi de la digestió de nutrients és d'especial rellevància en patologies que cursen amb alteracions pancreàtiques o hepàtiques, associades a una digestió de lípids compromesa en l'etapa intestinal, a causa de la disminució de secreció de pancreatina, bicarbonat i sals biliars. Aquest és el cas de la fibrosi quística amb insuficiència pancreàtica. Els pacients que pateixen aquesta afecció han de seguir la teràpia de substitució d'enzims pancreàtics, que consisteix en el subministrament exogen de pancreatina encapsulada. No obstant això, la dosi d'aquest suplement ha d'ajustar-se a les característiques dels aliments i actualment no es disposa de cap mètode vàlid per a tal fi. Per enfrontar a aquest repte, en el projecte finançat amb fons europeus, MyCyFAPP, s'ha aconseguit desenvolupar un mètode per a ajustar la dosi òptima dels suplements enzimàtics utilitzats en la teràpia. La present tesi doctoral es va realitzar en el marc d'aquest projecte.
Concretament, aquesta tesi té com a objectiu abordar l'estudi de la digestió de lípids en els aliments d'origen animal (ous, carn i productes carnis, formatge i peix) en el context de la fibrosi quística. Per a abordar aquest objectiu es va aplicar un model de digestió in vitro estàtic amb la finalitat d'explorar el paper de les característiques inherents als aliments (estructura de la matriu alimentària com a resultat del processament) i els factors relacionats amb l'individu (pH, concentració de sals biliars i concentració de pancreatina) com a factors determinants de la lipòlisi en aliments d'origen animal.
Als quatre capítols presentats, centrats en l'ou, carn, formatge i peix, es presenta un disseny experimental comú per a estudiar la lipòlisi, la proteòlisi i la degradació de la matriu. En cada estudi, les diferents tècniques de processament aplicades als aliments avaluats també van permetre avaluar l'efecte de les propietats inherents als aliments en els resultats de l'estudi. Els resultats han contribuït al desenvolupament d'un nou mètode basat en l'evidència per a optimitzar la teràpia de substitució d'enzims pancreàtics i informen la comunitat científica sobre nous coneixements en el comportament de diferents aliments sotmesos al procés de digestió.<br>[EN] Among the available methodologies to study food digestion, in vitro digestion models have raised as a valid procedure. In vitro digestion consists of simulating the digestion process in the laboratory, by reproducing the physiological conditions in terms of digestive fluids composition (electrolytes and enzymes), pH, temperature, mechanical forces and duration of the oral, gastric and intestinal stages.
Addressing the study of nutrient digestion is of special relevance in pathologies coursing with pancreatic or hepatic alterations, which are associated with compromised intestinal lipid digestion due to reduced secretion of pancreatin, bicarbonate and bile salts. This is the case of Cystic Fibrosis along with pancreatic insufficiency, and the patients suffering this condition have to follow pancreatic enzyme replacement therapy, the exogenous supply of encapsulated pancreatin. However, the dose of this supplement should be adjusted to the specific characteristics of foods, and no valid method was available for such purpose. To tackle this challenge, the EU-funded project MyCyFAPP succeed to develop a method to adjust the optimal dose the enzyme supplements used in the therapy. The present doctoral thesis was conducted as a relevant part of this project.
Concretely, this thesis aims at addressing the study of lipid digestion in foods to generate new knowledge regarding nutrient digestion in animal origin dietary sources (egg, meat and meat products, cheese and fish) in the context of Cystic Fibrosis. To address this goal a static in vitro digestion model was applied. The role of inherent-to-food characteristics (resulting food matrix structure from processing) and host related factors (pH and bile salts concentration and pancreatin concentration) were explored as determinants of lipolysis in animal-origin foods.
Along the four chapters presented, focused on egg, meat, cheese and fish, a common experimental design was applied to study lipolysis, proteolysis and matrix degradation. In each study, different processing techniques applied to the assessed foods allowed for evaluating the effect of inherent-to-food properties on the study outcomes as well. The results have contributed to the development of a new evidence-based method to optimise pancreatic enzyme replacement therapy, and inform the scientific community about new insights on the behaviour of different foods undertaking the digestion process.<br>Authors of this paper acknowledge the European Union and the Horizon 2020
Research and Innovation Framework Programme (PHC-26-2014 call Self-management
of health and disease: citizen engagement and mHealth) for fully funding this research
in the context of MyCyFAPP Project, under grant agreement number 643806.
The authors would like to thank the Conselleria de Educació i Investigació de la
Generalitat Valenciana and also the European Union (“El Fondo Social Europeo (FSE)
invierte en tu futuro”) for the PhD scholarship given to Andrea Asensio Grau
(ACIF/2017/008). This study was developed thanks to the equipment funded with the
support from the Generalitat Valenciana IDIFEDER/2018/041 (PO FEDER Comunitat
Valenciana 2014-2020). Finally, we thank
Antonio Martínez Cañada, from the Data Science and Biostatistics Unit of Instituto de
Investigación Sanitaria La Fe, and Arash Javanidejad for the English corrections.<br>Asensio Grau, A. (2021). In vitro approach of dietary and host related factors affecting digestion of animal-origin foods under cystic fibrosis disease [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/171512<br>TESIS<br>Compendio
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Bangyeekhun, Eakaphun. "Parasite on Crayfish : Characterisation of Their Pathogenesis, Host Interactions and Diversity." Doctoral thesis, Uppsala University, Comparative Physiology, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-2770.
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<p>The crayfish plague refractory crayfish, <i>Pacifastacus leniusculus</i>, which can harbour the fungal parasite within melanotic sheath, are found to constitutively express the gene encoding for prophenoloxidase (proPO) after mimicking parasite attack. In contrast, the susceptible crayfish, <i>Astacus astacus</i>, responds to the parasite by increased levels of proPO transcript, particularly in the semigranular haemocytes. The upregulation of proPO could confer a temporary resistance towards the fungal infection, suggesting that additional factors are involved in maintaining the balance between host and parasite. The resistant crayfish may have adapted to the parasite by increasing the transcript level of immune genes. The parasite can be considered as a symbiont since it does not harm the host rather than it activates the immune gene and possibly preventing other pathogens to become established.</p><p>Two serine proteinase genes encoding a subtilisin-like (<i>AaSP1</i>) and a trypsin (<i>AaSP2</i>) enzyme were isolated from the crayfish plague fungus, <i>Aphanomyces astaci</i>. These proteinases are prepropeptides and generate mature proteins of 39 kDa and 29 kDa, respectively. Characterisation of <i>AaSP1</i> suggests that the enzyme may be involved in intracellular control mechanisms rather than playing a role in pathogenesis. The <i>AaSP2 </i>transcript was not controlled by catabolic repression, but was induced by crayfish plasma, implying a role in pathogenesis toward the crayfish host. </p><p>Physiology and genetics of five <i>Aphanomyces</i> strains, which were isolated from moribund crayfish, were characterised with regard to their pathogen diversity. These strains are not virulent against crayfish. Some physiological properties of these strains differed from <i>A. astaci</i>, such as growth rate, germination and production of chitinase. Genetic analysis clearly indicated that they are not related to <i>A. astaci</i> and their name are proposed to be <i>Aphanomyces repetans</i>.</p><p>The crayfish <i>P. leniusculus </i>was found to be susceptible to white spot syndrome virus infection. The virus has a significant effect to the population of crayfish haemocyte. The number and proportion of granular cell from virus-infected crayfish were higher than in controls, indicating granular cells are more resistant to and may interact by some means with the virus.</p><p>Two morphotypes of the crayfish parasite <i>Psorospermium haeckeli</i> obtained from different crayfish hosts of different geographical origin were analysed for ribosomal ITS DNA in order to compare their genetic diversity. The sequence difference between them was found largely in ITS 1 and ITS 2 regions, which was variable in length and showed 66% and 58% sequence similarity. Thus, different morphotypes of <i>P. haeckeli</i> are genetically diverse.</p>
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Buchholz, Matthew J. "Host-Parasite Associations of Small Mammal Communities and Implications for the Spread of Lyme Disease." TopSCHOLAR®, 2016. http://digitalcommons.wku.edu/theses/1588.
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Many zoonotic pathogens of concern to human and veterinary health are maintained in the environment within small mammal reservoirs and vectored to new hosts by ectoparasitic arthropods. While the ecological relationships among small mammals, ectoparasites, and disease-causing symbiotic microorganisms are important to these dynamics, little is known about them across much of North America. The sylvatic cycle of Borrelia burgdorferi, the etiologic agent of Lyme disease, is of particular interest because Lyme disease is the most common vector-borne disease of humans in the United States. However, cases of Lyme disease are primarily confined to the northeastern and Midwestern United States, with only sporadic cases extending into the southeast. As a result, much of what is known of the ecology of Lyme disease comes from studies conducted in those regions. The goal of this study was to examine the ecological dynamics of the B. burgdorferi/vector/reservoir system in south-central Kentucky and gain insight into the relative paucity of Lyme disease in Kentucky. Small mammals were captured using live traps in three 200x50 m trapping grids within Western Kentucky University’s Green River Preserve from November 2014-October 2015. Captured small mammals were identified to species and standard measurements were recorded. Ectoparasites were removed and retained for identification. Collected blood and tissue were examined for B. burgdorferi DNA by polymerase chain reaction with primers specific to the OspA gene. The Bray-Curtis dissimilarity index, Schnabel population estimates, and the Shannon-Wiener diversity index were used to assess the structure of the small mammal communities. Parasite infestation was low but was affected by age and sex of the host, site, and season in different parasite taxa. Infestation by Ixodes scapularis, the primary vector for B. burgdorferi, was uncommon and prevalence of B. burgdorferi in blood was similar to the lowest prevalence previously observed in the Lyme disease endemic regions. We found that life history characteristics of hosts and ectoparasites drive their associations. We also suggest that the lack of an efficient vector for B. burgdorferi is the likely explanation for the few reported cases of Lyme disease in Kentucky.
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Davies, Claire Louise. "Parasite dynamics and community richness in a naturally fragmented water vole (Arvicola amphibious) metapopulation." Thesis, University of Aberdeen, 2014. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=228192.
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Fragmentation can drive local populations to become smaller and more isolated, and consequently more susceptible to extinction. Movement between patches, however, can interconnect such populations so that they effectively behave as larger and more stable metapopulations. Over the past two decades metapopulations have been used to shed light on the complex interactions that occur between hosts and parasites. Effectively every host can be considered as a discrete habitat patch from the perspective of a parasite. As such, host-parasite interactions naturally lend themselves to being examined within the metapopulation paradigm. In this thesis I examine empirically how various aspects of metapopulation structure, such as local host population size and landscape isolation/connectivity, combine to determine the extinction and recolonization dynamics of parasites in the landscape. Using a naturally fragmented water vole (Arvicola amphibious) metapopulation, I describe the spatial and temporal variation in parasite infection prevalence or burden in a Scottish landscape. I specifically address the spatial and temporal dynamics of both ectoparasites, and vectortransmitted microparasites, since these are two groups of parasites commonly found in natural systems yet often overlooked in the host-parasite metapopulation literature. In addition, I attempt to understand how specific parasite characteristics, such as transmission mode and infectious period, can influence how parasites respond to host population structure. In the final chapter, I bring together a number of parasite groups to examine the impact of metapopulation dynamics on parasite communities as a whole by investigating its impact of parasite community richness. Overall the findings of my study indicate that host spatial structure and the level of connectivity between patches are important factors that affect parasite dynamics and community richness. However, the exact level of connectivity required to sustain a parasite population locally depended on specific parasite characteristics. In contrast, local effects host/vector population size and patch infection history) had no discernible impact on most parasite groups.
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West, Christopher. "The effect on phytophagous insects of variations in defence mechanisms within a plant." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670399.
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Månsson, Lisa. "Visualizing the dynamic interplay between the host and bacterial pathogen : a real-time study of renal infection /." Stockholm, 2007. http://diss.kib.ki.se/2007/978-91-7357-218-7/.
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Yanhua, Li. "Identification of PRRSV nonstructural proteins and their function in host innate immunity." Diss., Kansas State University, 2014. http://hdl.handle.net/2097/18663.
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Doctor of Philosophy<br>Department of Diagnostic Medicine/Pathobiology<br>Ying Fang<br>Porcine reproductive and respiratory syndrome virus (PRRSV) employs multiple functions to modulate host’s innate immune response, and several viral nonstructural proteins (nsps) are major players. In this dissertation, the research was mainly focused on identification and functional dissection of ORF1a-encoded nsps.
PRRSV replicase polyproteins encoded by ORF1a region are predicted to be processed into at least ten nonstructural proteins. In chapter 2, these predictions were verified by using a panel of newly established antibodies specific to ORF1a-encoded nsps. Most predicted nsps (nsp1β, nsp2, nsp4, nsp7α, nsp7β and nsp8) were identified, and observed to be co-localized with de novo-synthesized viral RNA in the perinuclear region of the cell.
Among all PRRSV proteins screened, nsp1β is the strongest type I interferon antagonist. In chapter 3, mutagenesis analysis of nsp1β was performed to knock down nsp1β’s IFN antagonist function. A highly conserved motif, GKYLQRRLQ, was determined to be critical for nsp1β’s ability to suppress IFN-β and reporter gene expression. Double mutations introduced in this motif, K130A/R134A (type 1 PRRSV) or K124A/R128A (type 2 PRRSV), improved PRRSV’s ability to stimulate the expression of IFN-α, IFN-β and ISG15. In addition to its critical roles involving in modulating host innate immune response, in the studies of Chapter 4, we demonstrated that PRRSV nsp1β functions as a transactivator to induce the -2/-1 ribosomal frameshifting in nsp2, which results in expression of two novel PRRSV proteins, nsp2TF and nsp2N. The conserved motif GKYLQRRLQ is also determined to be critical for the transactivation function of nsp1β.
In chapter 5, the interferon antagonist, de-Ub and de-ISGylation activity of newly identified nsp2TF and nsp2N were evaluated. In vitro and in vivo characterization of three nsp2TF-deficient recombinant viruses indicated that all mutant viruses have improved ability to stimulate the innate immune response and provide improved protection in mutant virus-vaccinated animals.
In summary, this study verified the previously predicted PRRSV pp1a processing products, further evaluated the function of nsp1β and nsp2-related proteins. These data obtained here will provide basic knowledge for future development of vaccines and control measurements.
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Machmouchi, Dana. "Exploring the Pathogenic Mechanisms of West African Zika Virus : viral Replication and Host Interaction." Electronic Thesis or Diss., La Réunion, 2024. https://elgebar.univ-reunion.fr/login?url=http://thesesenligne.univ.run/24_14_D_MACHMOUCHI.pdf.
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Le virus Zika (ZIKV), historiquement limité à l'Afrique et à l'Asie, est devenu une préoccupation mondiale majeure, surtout après les épidémies récentes dans les Amériques associées à des malformations congénitales graves et des troubles neurologiques. Bien que la recherche se soit principalement concentrée sur le génotype asiatique/américain, des preuves croissantes montrent que les souches africaines du ZIKV pourraient également représenter une menace sévère, notamment en termes de pathogénicité fœtale. Cette thèse vise à améliorer notre compréhension des mécanismes moléculaires de la pathogénicité des souches contemporaines de ZIKV d'Afrique de l'Ouest, en mettant l'accent sur les protéines non structurales dans la réplication virale, l'évasion immunitaire et la réponse au stress des cellules hôtes.Pour cela, nous avons généré un clone moléculaire infectieux, GUINEA-18, à partir d'une souche de ZIKV (ZIKV-15555) isolée en Guinée en 2018, représentant une souche contemporaine de la lignée africaine. Nous avons comparé ce clone avec le clone bien caractérisé de la souche historique MR766 (MR766MC). Les propriétés de réplication des deux clones ont été examinées dans les lignées cellulaires VeroE6, A549 et HCM3. GUINEA-18 a montré un taux de réplication plus lent, une cytotoxicité réduite et une moindre capacité à activer le système immunitaire inné comparé à MR766MC, suggérant une interaction différente avec les cellules hôtes.Pour explorer ces différences, nous avons construit des virus chimériques en échangeant les régions codantes des protéines non structurales entre GUINEA-18 et MR766MC. Nos résultats ont souligné les rôles critiques des protéines NS1 à NS4B dans la réplication et la pathogénicité, avec NS4B étant clé pour GUINEA-18. Nous avons également découvert que GUINEA-18 inhibe efficacement l'assemblage des granules de stress cytoplasmiques (SGs) dans les cellules A549, un mécanisme de défense cellulaire. Cette inhibition dépend des protéines NS1 à NS4B, soulignant leur rôle dans l'évasion des défenses de l'hôte.La thèse examine aussi le rôle de NS1 dans la pathogénicité des souches contemporaines. L'alignement des séquences protéiques a révélé sept substitutions dans la protéine NS1 de GUINEA-18 par rapport à celle de MR766. Ces mutations montrent que NS1CWA est sécrétée plus efficacement et présente une localisation subcellulaire différente de NS1MR766, augmentant la réplication virale et la cytotoxicité tout en réduisant l'activation des réponses immunitaires. Un virus chimérique MR766 avec NS1CWA a montré ces traits pathogéniques renforcés, soulignant l'importance de NS1 dans la virulence des souches contemporaines du ZIKV d'Afrique de l'Ouest.En conclusion, cette thèse analyse les déterminants moléculaires de la réplication et de la pathogénicité des souches contemporaines du ZIKV d'Afrique de l'Ouest. Les recherches mettent en évidence les rôles critiques des protéines NS1 à NS4B, en particulier NS1 et NS4B. Les résultats soulèvent des questions sur les risques associés aux souches actuelles du ZIKV en Afrique subsaharienne et soulignent la nécessité de surveillance continue pour comprendre les implications pour la santé publique. Ce travail offre des perspectives pour les stratégies de gestion et de prévention des maladies associées au ZIKV, surtout dans les régions où la lignée africaine est prévalente<br>The Zika virus (ZIKV), historically confined to Africa and Asia, has become a significant global health concern, especially after recent outbreaks in the Americas linked to severe congenital malformations and neurological disorders. While much research has focused on the Asian/American ZIKV genotype, evidence suggests that African ZIKV strains might also pose a serious threat to public health, particularly regarding fetal pathogenicity. This thesis aims to enhance our understanding of the molecular mechanisms underlying the pathogenicity of contemporary ZIKV strains from West Africa, focusing on nonstructural proteins involved in viral replication, immune evasion, and the host cell stress response.To achieve this, we generated an infectious molecular clone, GUINEA-18, from a ZIKV strain (ZIKV-15555) isolated in Guinea in 2018. This clone represents a contemporary African ZIKV strain. We compared it with the infectious molecular clone of the historical African ZIKV strain MR766, designated MR766MC. The replication properties of both viral clones were examined in VeroE6, A549, and HCM3 cells. GUINEA-18 exhibited a slower replication rate, reduced cytotoxicity, and a lower ability to activate the host’s innate immune system compared to MR766MC, suggesting different interactions with host cells.To dissect these differences, we created chimeric viruses by swapping nonstructural protein-coding regions between GUINEA-18 and MR766MC. Results highlighted the critical roles of NS1 to NS4B proteins in replication efficiency and pathogenicity, with NS4B being crucial for GUINEA-18’s replication properties. GUINEA-18 also developed an efficient mechanism to inhibit the assembly of cytoplasmic stress granules (SGs) in A549 cells, a defense mechanism typically triggered by viral infection. The ability of GUINEA-18 to block SG formation depended on the NS1 to NS4B proteins, underscoring their role in evading host defenses.Further investigation into the NS1 protein revealed seven amino acid substitutions in GUINEA-18 compared to MR766. Functional analyses showed that the contemporary NS1 protein (NS1CWA) is secreted more efficiently and has a different subcellular localization than NS1 from MR766 (NS1MR766). This altered behavior of NS1CWA significantly enhances viral replication and cytotoxicity while reducing the activation of innate immune responses in infected cells. A chimeric MR766 virus containing NS1CWA demonstrated these enhanced traits, emphasizing NS1’s role in the virulence of contemporary West African ZIKV strains.In conclusion, this thesis provides a comprehensive analysis of the molecular determinants of replication and pathogenicity in contemporary West African ZIKV strains. The research underscores the crucial roles of NS1 to NS4B proteins, particularly NS1 and NS4B, in these processes. The findings raise questions about risks associated with circulating ZIKV strains in sub-Saharan Africa and highlight the need for ongoing surveillance and research to understand the public health implications. This work contributes valuable insights that could inform future strategies for managing and preventing ZIKV-associated diseases, especially in regions where the African lineage of the virus is prevalent
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Ansebo, Lena. "Odour perception in the codling moth Cydia pomonella L. (Lepidoptera torticidae): from brain to behaviour /." Alnarp : Dept. of Crop Science, Swedish Univ. of Agricultural Sciences, 2004. http://epsilon.slu.se/a474.pdf.
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Teixeira, Laura Helena Marcon. "Aspectos epidemiológicos da raiva animal e avaliação da diversidade de morcegos e de seus ectoparasitas na microrregião Quirinópolis, Goiás, Brasil." Universidade Federal de Goiás, 2013. http://repositorio.bc.ufg.br/tede/handle/tede/3211.
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Previous issue date: 2013-08-30<br>Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG<br>Pneumonia is of the main causes of death of children under 5 years of age. Several health
organizations worldwide, public and private, are engaged in investigating the disease and
evaluate the effectiveness of mechanisms to prevent and combat existing.
Infections causing pneumonia can be avoided. However, especially in poor countries, the
resources to promote prevention are scarce. Thus the combat actions need to be very
efficient and effective. To ensure the effectiveness of these actions, such as vaccines, are
necessary statistical information like age range, region, period, social status and history
obtained through field research.
This paper proposes and implements a software architecture for the construction, use and
maintenance of research of childhood pneumonias. The techniques, technologies, tools
and services used in defining the architecture were chosen with a focus on low cost. This
way is much more feasible to use software for automated search systems by healthcare
entities that have few financial resources.<br>As pneumonias estão entre as principais causas de morte das crianças com menos de
5 anos de idade. Várias entidades de saúde no mundo todo, públicas e privadas, estão
empenhadas em investigar a doença e avaliar a eficiência dos mecanismos de prevenção e
combate existentes.
As infecções que causam pneumonia podem ser evitadas. No entanto, principalmente em
países pobres, os recursos para promover a prevenção são escassos. Assim as ações de
combate precisam ser muito eficientes e eficazes. Para garantir a efetividade dessas ações,
como as vacinas, são necessárias informações estatísticas como faixa etária, região, época,
condição social e histórico obtido através de pesquisa em campo.
Este trabalho propõe e implementa uma arquitetura de software para construção, uso e
manutenção de sistemas de pesquisa das pneumonias na infância. As técnicas, tecnologias,
ferramentas e serviços utilizados na definição da arquitetura foram escolhidos com
foco no baixo custo. Dessa forma fica muito mais viável a utilização de softwares para
sistemas de pesquisa automatizados por entidades de saúde que possuem poucos recursos
financeiros.
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Manha, Alessandra Popov dos Santos. "Análise da expressão diferencial em três fases da esporulação de oocistos de Eimeria maxima." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/42/42135/tde-25102011-150441/.
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Eimeria maxima é uma das principais espécies que causam a coccidiose aviária. Visando uma maior compreensão dos mecanismos moleculares envolvidos na esporulação de oocistos de E. maxima, o perfil da expressão gênica em oocistos não esporulados, parcialmente esporulados e esporulados foi avaliado utilizando a técnica ORESTES. As 20.149 leituras geradas foram pré-processadas, agrupadas, anotadas empregando-se a plataforma Egene e em seguida, analisadas estatisticamente. Um total de 1.207 contigs e 2091 singlets foi gerado. Cerca de 72% dos transcritos foram classificados como proteínas hipotéticas, 20% eram similares a proteínas de função conhecida e 8% eram proteínas conservadas. Após a análise estatística, 32% dos transcritos foram classificados como diferencialmente expressos, dos quais, a maioria (65%) era estágio-específica. Para validação dos perfis de expressão obtidos por ORESTES, a expressão diferencial de um pequeno conjunto de genes foi quantificada por RT-qPCR. Os resultados demonstraram boa correlação entre as duas técnicas.<br>Eimeria maxima is one of the most important causing agents of poultry coccidiosis. Aiming at obtaining a better understanding of the molecular mechanisms involved in oocyst sporulation of E. maxima, the gene expression profiles of unsporulated, sporulating (sporoblast phase) and sporulated oocyst were studied using the ORESTES methodology. The 20,149 reads generated were pre-processed, grouped, annotated employing the platform Egene and statistically analyzed. A total of 1207 contigs and 2091 singlets were generated. About 72% of the transcripts were classified as hypothetical proteins, 20% were similar to proteins of known function and 8% were conserved proteins. After statistical analysis, 32% of the transcripts were classified as differentially expressed of which 65% were stage-specific. For ORESTES validation, the differential expression was quantified by RT-qPCR to a small set of genes. The results demonstrated a good correlation between the two techniques studied.
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Dell'Aglio, Denise Dalbosco. "Ecologia comportamental e diversidade em um sistema hospedeiro-parasitóide : vespas parasitóides de Schismatodiplosis lantanae Rübsaamen, 1916 (Cecidomyiidae) em Lantana camara L. (Verbenaceae)." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/60549.
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Este estudo investigou a ecologia de vespas parasitóides ocorrentes em galhadores Schismatodiplosis lantanae Rübsaamen, 1916 (Cecidomyiidae) em folhas de Lantana camara L. (Verbenaceae). Dessa forma, o primeiro artigo trata da ecologia comportamental da vespa parasitóide Torymus sp. (Torymidae, Hymenoptera), onde foi avaliado como as fêmeas dessa espécie defendem seu recurso de oviposição no hospedeiro. Foi analisado mudanças no comportamento devido à presença de outra fêmea coespecífica no local, ser residente do recurso, tamanho das vespas e número e tamanho das galhas através de filmagens dos experimentos realizados em laboratório. Com esse trabalho observou-se que fêmeas mudam seu comportamento quando estão na presença de um competidor em um território com hospedeiros. A estratégia de ataque foi através da ameaça, na qual suas antenas e asas são levantadas para expulsar o competidor do local. A probabilidade de haver ataques a fêmeas coespecíficas depende do tempo prévio de exploração da galha e da permanência na folha. O interesse no hospedeiro pelas invasoras foi a principal causa de conflitos com a residente. O segundo artigo trata da diversidade de vespas parasitóides e de um ciclo parasita-hospedeiro observado no período de um ano no sistema de L. camara. Foram encontradas nove espécies de vespas parasitóides, divididas em quatro famílias. Ocorreu um ciclo no parasitismo das espécies de vespas sobre seu hospedeiro no ano amostrado, podendo ser observado que são mais elevadas nos meses de Julho a Janeiro e a sobrevivência do hospedeiro foi maior nos meses de Fevereiro a Maio. As estratégias comportamentais de fêmeas de uma vespa parasitóide em relação a seus hospedeiros foram analisadas, bem como um sistema composto de diversas espécies parasitóides e sua variação no tempo. Estas observações podem contribuir para um melhor entendimento da ecologia comportamental e do padrão temporal das vespas parasitoides, e também para futuros programas de controle biológico mais eficientes.<br>We investigated the ecology of parasitoid wasps attacking Schismatodiplosis lantanae Rübsaamen, 1916 (Cecidomyiidae) galls on leaves of Lantana camara L. (Verbenaceae). The first article discusses the behavioral ecology of the parasitoid wasp Torymus sp. (Torymidae, Hymenoptera), reporting how their females defend oviposition resources on the hosts, changing their behavior due to the presence of a conspecific female in the patch. The identity of the wasp (resident or intruder) on the resource, female size and number and size of galls in the patch were factors studied through analysis of the behaviors revealed by video recordings of the laboratory experiments. Females change their behavior in the presence of a competitor in a territory with hosts. The strategy was to threat, raising their antennae and wings to expel the competitor of the patch. The probability of an attack on a conspecific females depended on the host exploitation time and time spent on the galled leaf. Interest in host by intruders was the main cause for conflicts. The second article reports the diversity of parasitoid wasps and a host-parasite cycle during one year period in the L. camara leaf galls system. Nine parasitoid wasp species were found, divided in four families. A cycle between parasitism and host survival was found during the sampling period. Wasp species are more abundant from July to January and host survival higher from February to May. Behavioral strategies of parasitoid wasp females toward their hosts and conspecifics have been elucidated, with the system composed of different parasitoid wasp species apparently going through an annual cycle of parasitism rate. These observations may contribute to a better understanding of parasitoid behavioral ecology and host-parasitoid dynamics, enabling more efficient future biological control programs.
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Björkman, Maria. "Effects of intercropping on the life cycle of the turnip root fly (Delia floralis) : behaviour, natural enemies and host plant quality /." Uppsala : Dept. of Crop Production Ecology, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/2007125.pdf.
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Al, Moussawi Khatoun. "Etude cellulaire et physiopathologique de l'interaction hôte - Tropheryma whippleii." Thesis, Aix-Marseille 2, 2011. http://www.theses.fr/2011AIX20674.
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Tropheryma whipplei a longtemps été uniquement considérée comme l’agent responsable de la maladie de Whipple, une affection rare caractérisée notamment par une perte de poids, des diarrhées chroniques et des douleurs abdominales. Toutefois, au cours de ces dernières années, il est apparu que les infections à T. whipplei peuvent présenter des manifestations cliniques communes telles que des pneumonies, des bactériémies fébriles ou des gastroentérites, ce qui montre que la maladie de Whipple ne constitue pas la seule manifestation de l’infection à T. whipplei. Ma thèse a eu deux objectifs. Le premier a été de caractériser l’interaction entre T. whipplei et la cellule dans laquelle elle se réplique, le macrophage. J’ai montré en utilisant diverses techniques (biologie moléculaire à haut débit, biologie cellulaire et biochimie) que T. whipplei induit une réponse macrophagique inédite caractérisée par une polarisation M2 associée à une réponse interféron de type I. J’ai également montré que ces événements sont associés à l’apoptose des macrophages dont l’induction se fait par voie extrinsèque et que l’IL-16, pour laquelle un rôle au cours de l’infection à T. whipplei était avéré, intervient d’une part dans le blocage de la maturation phagosomale et d’autre part interfère avec l’activation des macrophages. Mon second objectif a été de montrer à travers un modèle animal que la primo-infection par T. whipplei se manifeste par une gastroentérite auto-résolutive. Cet objectif découlait directement de travaux récents qui associent T. whipplei à diverses manifestations cliniques et notamment à des épisodes diarrhéiques chez l’enfant. Mes résultats confortent clairement cette hypothèse et montrent également que des dommages préexistants de la muqueuse intestinale permet l’établissement de l’infection à T. whipplei<br>Tropheryma whipplei has only been considered as the agent of Whipple‘s disease, a rare disease characterized by weight loss, chronic diarrheas and abdominal pains. It is now believed that infections with T. whipplei result in common clinical manifestations, such as pneumonia, fever, bacteriema or gastroenteritis and, as a consequence, it is likely that the Whipple’s disease is not the only manifestation of T. whipplei infection. During my PhD, I had 2 objectives. The first was to characterize the interaction between T. whipplei and the cell type in which T. whipplei replicates, namely macrophages. I showed using diverse techniques (high throughput molecular biology, cell biology and biochemistry) that T. whipplei induced an unusual macrophage response, characterized by M2 polarization with type I interferon response. I also showed that these events were associated with apoptosis of macrophages induced by the extrinsic pathway and that IL-16, which was already described during T. whipplei infection, was involved in the blockade of the phagosomal maturation and interfered with macrophage activation. The second objective was to show using a murine model that primary infection with T. whipplei results in self-limiting gastroenteritis. This objective directly arose from recent work that associated T. whipplei with various clinical manifestations and, in particular, with diarrheal episodes in children. My results clearly verified this hypothesis and also revealed that pre-existing mucosal damage allowed the establishment of the infection
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Cordeiro, Joacir Graciolli. "A utilização de sistemas computacionais no desenvolvimento e análise do modelo animal de Kindling Hipocampal/." oai:ufpr.br:239521, 2007. http://200.17.209.5:8000/cgi-bin/gw_42_13/chameleon.42.13a?host=localhost%201111%20DEFAULT&sessionid=VTLS&function=CARDSCR&search=KEYWORD&pos=1&u1=12101&t1=239521.
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Anexos<br>Orientador: João Cândido Araújo<br>Co-orientador: Andreas Schulze Bonhage<br>Dissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências da Saúde, Programa de Pós-Graduação em Clínica Cirúrgica. Defesa: Curitiba, 18 de dezembro de 2007.<br>Inclui bibliografia<br>Área de concentração: Informática no Ensino e na Pesquisa em Cirurgia
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Hannunen, Salla. "Trivial movements and redistribution of polyphagous insect herbivores in heterogeneous vegetation /." Uppsala : Swedish Univ. of Agricultural Sciences, Dept. of Entomology, 2003. http://epsilon.slu.se/a376.pdf.
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Piazzetta, Ricardo Guimarães. "Produção e comportamento animal em pastagem de aveia e azevém, submetida a diferentes alturas de manejo /." oai:ufpr.br:233906, 2007. http://200.17.209.5:8000/cgi-bin/gw_42_13/chameleon.42.13a?host=localhost%201111%20DEFAULT&sessionid=VTLS&function=CARDSCR&search=KEYWORD&pos=1&u1=12101&t1=233906.
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Orientador: João Ricardo Dittrich<br>Co-orientadores: Sergio José Alves, Aníbal de Moraes e Sebastião Brasil Campos Lustosa<br>Dissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Agrárias, Programa de Pós-Graduação em Ciências Veterinárias. Defesa: Curitiba, 2007<br>Inclui bibliografia e anexo<br>Área de concentração: Produção animal
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O'Connell, Dean Michael, and n/a. "Plant-arthropod interactions : domatia and mites in the genus Coprosma (Rubiaceae)." University of Otago. Department of Botany, 2009. http://adt.otago.ac.nz./public/adt-NZDU20090807.160026.
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Plant-based defence mutualisms involve aspects of plant morphology that influence the performance of plant parasites, their natural enemies and trophic interactions. Leaf domatia, small indentations on the underside of leaves, can be structurally complex, and are often inhabited by potentially beneficial mites and other arthropods. Plant morphological traits such as domatia that enhance mutualistic relationships may result in increased plant growth rates, and reproductive success. New Zealand supports ~60 plant species that have domatia, the most speciose genus being Coprosma. The aim of this thesis was to examine factors that affect the production of leaf domatia and their relationship with foliar mite assemblages. The three main objectives of this thesis are: First, to investigate the production of foliar domatia and their susceptibility to limited resources, particularly to carbon availability. Second, to test if domatia are inducible structures during leaf ontogeny in the presence of foliar mites and/or fungi. Finally, to explore the effect of domatia availability on foliar mite assemblages on leaves with and without resident mites. This thesis tested the stated objectives using C. lucida, C. ciliata, C. foetidissima and C. rotundifolia, with a combination of field investigations and controlled manipulative experiments. The cost of domatia production was investigated using two field surveys and two controlled experiments. Under natural conditions the relationship between leaf morphology and domatia were measured in situ and across an altitudinal gradient. The experimental manipulations used carbon and nutrient stress, induced by temperature, light and fertilizer application. The second objective was experimentally tested under field conditions by manipulating foliar mites and fungal densities on C. rotundifolia. The third objective was investigated by manipulating domatia availability on C. lucida shrubs across three different vegetation types. Under field conditions, the number of domatia per leaf was associated with leaf morphology in C. lucida and C. foetidissima, but not C. rotundifolia. Foliar carbon showed a positive, but weak association with domatia production in C. foetidissima and C. ciliata. Altitudinal induced-carbon stress on domatia production was ambiguous. Domatia production in C. foetidissima was positively associated to altitude in field survey (1), and negatively associated in the second survey, with no correlation found between carbon and altitude. Experimental C. rotundifolia shrubs held under elevated night-time temperatures showed a 2.5 fold increase in respiration, a 34% to 91% decrease in daily carbon gain, and 38% decrease in domatia per leaf mass. Domatia production showed no significant differences under nutrient stress. The results showed little evidence to support a role for induction of domatia. Domatia production in new leaves was similar across all experimental treatments. Diverse vegetation types supported 60% higher mite species. Leaves with domatia supported ~22 to 66% higher mite densities, greater colonisation success and more diverse mite assemblages, than those without domatia. In the pastoral vegetation, the absence of predatory mites on experimental shrubs resulted in no differences in fungivorous mite densities regardless of domatia availability. Plant investment in foliar domatia appears associated with the number of available sites on the leaf under field conditions. The role of carbon availability during leaf ontogeny suggests a complex and highly variable association with domatia production. Domatia are constitutive defence structures that influence mite assemblages, mediating both beneficial and antagonistic relationships. This thesis concludes that domatia are in part, carbon-based non-inducible structures that influence mite assemblages, plant-mite and mite-mite interactions, and increase the probability of successful colonisation.
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Forman, Daron. "Viral Abrogation of Stem Cell Transplantation Tolerance Causes Graft Rejection and Host Death by Different Mechanisms: A Dissertation." eScholarship@UMMS, 2002. https://escholarship.umassmed.edu/gsbs_diss/72.
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Tolerance-based stem cell transplantation using sub-lethal conditioning is being considered for the treatment of human disease, but safety and efficacy remain to be established. In order to study these two issues, we first established that mouse bone marrow recipients treated with sub-lethal irradiation plus transient blockade of the CD40-CD154 costimulatory pathway develop permanent hematopoietic chimerism across allogeneic barriers. Our conditioning regimen of 6 Gy irradiation, a short course of anti-CD154 mAb and 25 million fully allogeneic BALB/c bone marrow cells consistently produced long-term, stable, and multilineage chimerism in C57BL/6 recipients. Furthermore, chimeric mice displayed donor-specific transplantation tolerance, as BALB/c skin allografts were permanently accepted while third-party CBA/JCr skin allografts were promptly rejected. We next determined both the safety and efficacy of this protocol by infecting chimeric mice with lymphocytic choriomeningitis virus (LCMV) either at the time of transplantation or at several time points afterwards. Infection with LCMV at the time of transplantation prevented engraftment of allogeneic, but not syngeneic, bone marrow in similarly treated mice. Surprisingly, infected allograft recipients also failed to clear the virus and died. Post-mortem study revealed hypoplastic bone marrow and spleens. Hypoplasia and death in these mice required the combination of 6 Gy irradiation, LCMV infection on the day of transplantation, and an allogeneic bone marrow transplant but did not require the presence of anti-CDl54 mAb. Allochimeric mice infected with LCMV 15 days after transplantation were able to survive and maintain their bone marrow graft, indicating that the deleterious effects of LCMV infection on host and graft survival are confined to a narrow window of time during the tolerization and transplantation process. The final section of this thesis studied the mechanisms of graft rejection and death in sublethally irradiated recipients of allogeneic bone marrow and infection with LCMV at the time of bone marrow transplantation. Infection of interferon-α/β receptor knockout mice at the time of transplantation prevented the engraftment of allogeneic bone marrow, but the mice survived. Therefore, IFN-αβ is involved in the development of marrow hypoplasia and death, whereas a second mechanism is involved in blocking the development of chimerism in these mice. Through the use of depleting mAb's and knockout mice we demonstrate that three types of recipients survived and became chimeric after being given sublethal irradiation, anti-CD154 mAb, an allogeneic bone marrow transplant and a day 0 LCMV infection: mice depleted of CD8+ T cells, CD8 knockout mice, and TCR-αβ knockout mice. Our data indicate that the mediator of bone marrow allograft destruction in LCMV-infected mice treated with costimulatory blockade is a radioresistant CD8+ NK1.1- TCRαβ+ T cell. We conclude that a non-cytopathic viral infection at the time of transplantation can prevent engraftment of allogeneic bone marrow and result in the death of sub-lethally irradiated mice treated with costimulation blockade. The abrogation of allogeneic bone marrow engraftment is mediated by a population of CD8+ NK1.1- TCRαβ+ T cells and the mediator of hypoplasia and death is viral induction of IFN-αβ.
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Carossino, Mariano. "CELLULAR AND MOLECULAR BASIS OF EQUINE ARTERITIS VIRUS PERSISTENT INFECTION IN THE STALLION REPRODUCTIVE TRACT: CHARACTERIZATION OF LOCAL HOST-PATHOGEN INTERACTIONS MEDIATING LONG-TERM VIRAL PERSISTENCE." UKnowledge, 2018. https://uknowledge.uky.edu/gluck_etds/35.
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Equine arteritis virus (EAV) has a global impact on the equine industry being the causative agent of equine viral arteritis (EVA), a reproductive, respiratory, and systemic disease of equids. A distinctive feature of EAV infection is that it establishes long-term persistent infection in the reproductive tract of stallions and is continuously shed in the semen (carrier state). Recent studies showed that long-term persistence is associated with a specific allele of the CXCL16 gene (CXCL16S). However, the cellular and molecular mechanisms underlying the establishment and maintenance of persistent infection are yet to be determined. The studies were undertaken herein unequivocally demonstrated that the ampulla is the main EAV tissue reservoir rather than immunologically privileged tissues (i.e., testes) and that EAV has specific tropism for stromal cells and CD8+ T and CD21+ B lymphocytes but not glandular epithelium in the reproductive tract. Furthermore, persistent EAV infection is associated with a significant humoral, mucosal antibody and inflammatory response at the site of persistence, characterized by induction of high levels of neutralizing antibodies (IgG1), mucosal anti-EAV-specific IgA, IgG1, IgG3/5, and IgG4/7 with variable neutralizing efficacy; and moderate, multifocal lymphoplasmacytic ampullitis, with significant infiltration of T lymphocytes (mainly CD8+ and low numbers of FOXP3+ lymphocytes), CD21+ B lymphocytes, diverse Ig-secreting plasma cells, and Iba-1+ and CD83+ tissue macrophages/dendritic cells. Moreover, EAV long-term persistent infection is associated with a CD8+ T lymphocyte transcriptional profile with upregulation of T-cell exhaustion-related transcripts and homing chemokines/chemokine receptors (CXCL9-11/CXCR3 and CXCL16/CXCR6), orchestrated by a specific subset of transcription factors (EOMES, PRDM1, BATF, NFATC2, STAT1, IRF1, TBX21), which are associated with the presence of the susceptibility allele (CXCL16S). Finally, these studies have determined that long-term EAV persistence is associated with the downregulation of a specific seminal exosome-associated miRNA (eca-mir-128) along with an enhanced expression of CXCL16 in the reproductive tract, a putative target of eca-mir-128. These findings provide evidence that this miRNA plays a crucial role in the regulation of the CXCL16/CXCR6 axis in the reproductive tract of persistently infected stallions, a chemokine axis strongly implicated in EAV persistence. The findings presented herein suggest that complex host-pathogen interactions shape the outcome of EAV infection in the stallion and that EAV employs complex immune evasion mechanisms favoring persistence in the reproductive tract. Further studies to identify specific mechanisms mediating the modulation of the CXCL16/CXCR6 axis and viral immune evasion in the reproductive tract of the EAV long-term carrier stallion are warranted.
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Burrells, Alison Clair. "Toxoplasma gondii in animal and human hosts." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/9628.
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The protozoan parasite Toxoplasma gondii (T. gondii) is an important zoonotic pathogen, which has the ability to infect all warm blooded mammals including humans, with approximately one third of the human population predicted to be infected. Transmission of the parasite to the foetus during pregnancy can result in miscarriage, however, a child infected during pregnancy may go on to develop clinical symptoms such as retinochoroiditis (ocular toxoplasmosis), hydrocephalus or learning difficulties in later life. Post-natally acquired infection in humans is generally asymptomatic, however, individuals who are immunocompromised may develop ocular toxoplasmosis or toxoplasmic encephalitis. T. gondii type II is reported to be the predominant genotype in Europe and the United States, but currently very little information exists about the prevalence and genotypes present within Great Britain. Consumption of T. gondii tissue cysts from raw or undercooked meat is a main source of infection for humans, with infected pork being considered a high risk. Currently the “gold standard” for assessing the viability of infective T. gondii tissue cysts is by an in vivo mouse bioassay. However, more recent ethical requirements to reduce, refine or replace experimental animals raises the question as to whether molecular technologies could be incorporated into these studies to reduce mouse numbers. The main aims of this PhD were to: (i) determine the prevalence and genotypes of T. gondii within different wildlife populations and humans in Great Britain; (ii) determine whether vaccination of pigs with a live attenuated strain of T. gondii would reduce the load of viable T. gondii tissue cysts within this species; (iii) study the viability and dissemination of tissue cysts from oocyst and bradyzoite infected pigs and (iv) to compare mouse bioassay with molecular detection of T. gondii DNA from experimentally infected pigs. The main findings of this work show that the prevalence of T. gondii within carnivorous wildlife varied from 6.0% to 44.4% depending on the host species with type II being the predominant lineage identified, however, type III and two alleles for type I were also present. In humans, serological detection of the parasite from a group of Scottish blood donors from Glasgow and Dundee (n=1403) was determined at 13.0%, molecular detection of T. gondii in human brains (n=151) from the Sudden Death Brain Bank show a prevalence of 17.9%. A correlation between increasing age and an increase in the detection of parasite was identified from both study groups. T. gondii strain genotyping using DNA extracted from human brains identified alleles for type I and III, however, no direct link between cause of death and detection of parasite DNA could be made. Live vaccination and subsequent oocyst challenge of pigs showed a significant reduction in the establishment of viable T. gondii tissue cysts. Mouse bioassay clearly demonstrates this result, where 100% of mice that were inoculated with homogenised tissues from vaccinated/challenged pigs survived, compared to the survival of only 51% of mice, which received homogenised tissues from non-vaccinated/oocyst challenged animals. In addition, porcine tissues from pigs challenged with either oocysts or bradyzoites did not show a significant difference in mouse survival following bioassay of these tissues. Challenge with either stage of the parasite (oocysts or bradyzoites) showed a preference to form tissue cysts in brains and highly vascular muscles (tongue, diaphragm, heart or masseter) of pigs. The findings, comparing mouse bioassay with molecular detection of parasite DNA from homogenised porcine tissue (prior to inoculation into mice), showed similar levels of detection. However, mouse bioassay was more sensitive and also provides evidence of parasite viability. In conclusion, this research not only provides current figures for prevalence and genotypes of T. gondii in both wildlife and humans in Great Britain, it also successfully answers the question as to whether live vaccination of pigs with the S48 strain can reduce the tissue cyst burden. These promising results show the potential of a vaccine against T. gondii in producing safer pork for human consumption. Although the mouse bioassay still remains the most sensitive method for the detection and viability assessment of tissue cysts, further research should be carried out in this area, perhaps incorporating a technique such as magnetic capture qPCR, to enable an effective in vitro technique to be developed.
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King, Marie A. "The Humanized Mouse Model: The Study of the Human Alloimmune Response: A Dissertation." eScholarship@UMMS, 2008. https://escholarship.umassmed.edu/gsbs_diss/374.
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The transplantation of allogeneic cells and tissues for the treatment of human disease has been a life-saving procedure for many thousands of patients worldwide. However, to date, neither solid organ transplantation nor bone marrow transplantation have reached their full clinical potential. Significant limitations to the advancement of clinical transplantation stem from our current inability to prevent the rejection of allogeneic tissues by the immune system of the host. Similarly, in patients that receive allogeneic bone marrow transplants, we cannot permanently prevent the engrafted immune system from mounting a response against the patient. This problem, termed graft versus host disease is the most prevalent cause of morbidity and mortality in recipients of allogeneic bone marrow transplants.
Clinically, we rely on lifelong immunosuppression to prolong survival of allogeneic tissues within the host. Our currently available therapeutics burden patients with side-effects that range from being unpleasant to life-threatening, while in most cases offering only a temporary solution to the problem of alloimmunity. Efforts are underway to develop protocols and therapeutics that more effectively prevent the pathology associated with alloimmunity. To minimize patient risk, extensive pre-clinical studies in laboratory animals are conducted to predict clinical responses. In the case of immunologic studies, many of these pre-clinical studies are carried out in murine models. Unfortunately, studies of murine immunity often do not predict outcomes in the clinic. One approach to overcome this limitation is the development of a small animal model of the human immune system.
In this dissertation, we hypothesized that NOD-scid IL2rγnull mice engrafted with human peripheral blood mononuclear cells (PBMC), termed the hu-PBMC-NOD-scid IL2rγnull model, would provide a model that more accurately reflects human immunity in vivo than other models currently available. To investigate this possibility, we first investigated whether NOD-scid IL2rγnull mice were able to support the engraftment of human PBMC. We found that NOD-scid IL2rγnull mice engraft with human PBMC at much higher levels then the previous gold standard model, the NOD-scid mouse. We then investigated the kinetics of human cell engraftment, determined the optimal cell dose, and defined the influence of injection route on engraftment levels. Even at low PBMC input, NOD-scid IL2rγnullmice reproducibly support high levels of human PBMC engraftment. In contrast to previous stocks of immunodeficient mice, we observed low intra- and interdonor variability of engraftment.
We next hypothesized that the human PBMC engrafted in NOD-scid IL2rγnull mice were functional and would reject transplanted allogeneic human tissues. To test this, human islets were transplanted into the spleen of chemically diabetic NOD-scid IL2rγnull mice with or without intravenous injection of HLA-mismatched human PBMC. In the absence of allogeneic PBMC, the human islets were able to restore and maintain normoglycemia. In contrast, human islet grafts were completely rejected following injection of HLA-mismatched human PBMC as evidenced by return to hyperglycemia and loss of human C-peptide in the circulation. Thus, PBMC engrafted NOD-scid IL2rγnull mice are able to provide an in vivomodel of a functional human immune system and of human islet allograft rejection.
The enhanced ability of NOD-scid IL2rγnull mice to support human cell engraftment gave rise to the possibility of creating a model of graft versus host disease mediated by a human immune system. To investigate this possibility, human PBMC were injected via the tail vein into lightly irradiated NOD-scid IL2rγnull mice. We found that in contrast to previous models of GVHD using human PBMC-injected immunodeficient mice, these mice consistently (100%) developed GVHD following injection of as few as 5x106PBMC, regardless of the PBMC donor used. We then tested the contribution of host MHC in the development of GVHD in this model. As in the human disease, the development of GVHD was highly dependent on host expression of MHC class I and class II molecules.
To begin to evaluate the extent to which the PBMC-engrafted NOD-scid IL2rγnull humanized mouse model of GVHD represents the clinical disease, we tested the ability of a therapeutic in clinical trials to modulate GVHD in these mice. In agreement with the clinical experience, we found that interrupting the TNFα signaling cascade with etanercept delayed the onset and severity of disease in this model. In summary, we conclude that humanized NOD-scid IL2rγnull mice represent an important surrogate for investigating in vivo mechanisms of both human islet allograft rejection and graft versus host disease.
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Östergård, Hannah. "Plant-seed predator interactions – ecological and evolutionary aspects." Doctoral thesis, Stockholm University, Department of Botany, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-7537.
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<p>Plant-animal interactions are affected by both abundance and distribution of interacting species and the community context in which they occur. However, the relative importance of these factors is poorly known. I examined the effects of predator host range, environmental factors, host plant populations, plant traits and fruit abortion on the intensity of pre-dispersal seed predation in 46 host populations of the perennial herb <i>Lathyrus vernus</i>. I recorded damage by beetle pre-dispersal seed predators, mainly <i>Apion opeticum </i>and <i>Bruchus atomarius</i> with different host ranges on <i>L. vernus</i> as well as on two additional host plants. Local seed predator population size was mainly influenced by plant population size, current seed production and beetle population size in the previous year, but was not strongly affected by connectivity. The monophagous seed predator was less abundant and had lower densities than the oligophagous. Both predator species had a strong ability to track fluctuations in seed production; intensity of predation increased with relative increases in seed production. Oligophagous predation on<i> L. vernus i</i>ncreased with the abundance of alternative hosts, but presence of<i> L. vernus</i> did not affect predation on alternative hosts. Abundances and trait preferences differed among three co-occurring seed predators, but were also associated with the abundance of the other species. Overall, seed predation influenced selection on flower number. I found clear indications of seed predator offence but no obvious plant defence. The pattern of fruit abortion was associated with reduced plant fitness since the seed predator had an advanced ability to locate fruits with high probability of retention. Taken together, different factors influencing abundance of the seed predator species, different preferences, and context dependent trait selection are likely to result in complex spatio-temporal variation in overall seed losses and trait selection in the common host plant.</p>
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Galvao, Flávio Henrique Ferreira. "Modelo experimental de doença do enxerto versus hospedeiro após transplante de intestino delgado." Universidade de São Paulo, 1998. http://www.teses.usp.br/teses/disponiveis/5/5132/tde-13072011-171433/.
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A doença do enxerto versus hospedeiro (DEVH) é uma grave complicação do transplante de órgãos sólidos, com alta mortalidade. Seu estudo tem sido limitado pela carência de modelos experimentais apropriados. Descreve-se um modelo de DEVH baseado no aumento do quimerismo, sua evolução clínica, histopatológica, do número das células quiméricas, do perfil das citocinas e da tolerância imunológica. Ratos Lewis (LEW) foram submetidos a transplante simultâneo de intestino delgado e medula óssea provenientes de ratos ACI (grupo de estudo - E) ou LEW (grupo controle - C), tratados com FK-506 (1 mg/Kg/dia) entre o 0 e 13o PO, e uma dose semanal daí por diante. Os ratos foram divididos nos seguintes grupos: E1- 6 ratos sacrificados no 120o PO. E2- 8 ratos após apresentarem sinais clínicos graves de DEVH entre o 189o e o 271o PO. Como controle, ratos LEW foram receptores dos mesmos tipos de enxertos provenientes de ratos LEW, submetidos à mesma imunossupressão e foram assim divididos: C1- 6 ratos sacrificados no 120o PO, C2- 5 ratos sacrificados entre o 223o e o 270o PO. A citometria de fluxo foi realizada para quantificar a porcentagem das células linfóides de ACI doadores no sangue periférico nos E1, E2 em 6 períodos: 30o PO, 65o PO, 95o PO, 120o PO, 160o PO, 200o PO. Os animais foram examinados 2 vezes por semana à procura de sinais de DEVH (rash cutâneo, perda de peso, de pelo e hiperqueratose). No sacrifício dos animais do grupo E1 e C1, foram colhidas amostras de língua (LI), de linfonodos cervicais (LC), intestino delgado do receptor e do enxerto para análise das citocinas IL-2, IL-4, IL-6, IL-10, IFN-gama e TNF-alfa por meio da reação em cadeia da polimerase. Em todos os grupos foram também colhidas amostras destes órgãos para histopatologia e nos animais do grupo E2 linfonodos cervicais foram processados para análise da reatividade celular por meio da reação mista dos linfócitos (MLR). A evolução clínica e histopatológica foi graduada de 0 a 3 de acordo com a severidade dos sintomas e do infiltrado mononuclear das amostras. Os ratos dos grupos E1 e E2 iniciaram sinais da DEVH entre o 84o e 115o PO. Os ratos dos grupos C1 e C2 não apresentaram evidência de DEVH. Amostras de LI e LC dos ratos do grupo E1 apresentaram alterações histopatológicas grau 2 e do grupo E2 apresentaram alterações histopatológicas grau 3, respectivamente. Nenhuma alteração histopatológica foi encontrada nos ratos do grupo controle e em amostras do ID. Nenhuma alteração histopatológica foi encontrada no intestino delgado do receptor e do enxerto. O aumento da porcentagem de células do doador no sangue periférico do receptor foi progressivo chegando a 5,4±2.3% no 10o período, 21±4,6% no 3o período e 39,3±4% no 6o período. IL-2, IL-6, IL-10, IFN-gma e TNF-alfa estiveram aumentados em língua e IL-4, IL-6, IL-10, IFN-gama e TNF-alfa em linfonodos cervicais. Os linfócitos de ratos do grupo E2 mostraram hiporreatividade aos de ratos ACI e hiperreatividade aos de ratos PVG (terceira parte) denotando tolerância imunológica. Neste modelo experimental há uma inexorável evolução imunológica para DEVH; existe correlação direta entre o aumento do quimerismo em sangue periférico e da expressão de citocinas em língua e linfonodos cervicais e a severidade da DEVH, além da indução de tolerância imunológica do rato do grupo E2 quimérico ao rato ACI normal.<br>Graft-versus-host disease (GVHD) has been a major concern after small bowel transplantation (SBTX) and the lack of suitable experimental models has limited the study of GVHD after solid organ transplantation. Here we describe a re1evant experimental model of GVHD after fully allogeneic SBTX based on chimerism augmentation, its clinical and histophatological evolution, cytokine involvement, responsible donor cell and immunologic tolerance analysis. LEW rat recipients received orthotopic SBTX and simultaneous donor bone marrow cell infusion (250x106), from ACI rats (experimental group - E) or LEW (control group C). FK-506 was administered dayly at a dose of 1 mg/kg on day 0 to 13, then continued as a weekly injection of same dose until the experimental end point. The recipients were divided in the following groups: E1 - 6 rats sacrificed at 120° POD. E2 - 8 rats sacrificed with critical GVHD between DPO 189 to 271. LEW recipient of LEW grafts, under the same immunossupression were used as control and divided as: C1 - 6 rats sacrificed at POD 120; C2- 5 rats sacrificed between 223 and 270 POD the number of donor cell in the recipient circulation was determined by flowcytometry in 6 pos-operative time: 30, 65, 95, 120, 160, 200. The rats were analyzed twice a week for body weigh and searching for signs of GVHD (cutaneous rush, hiperkeratosis and loss of hair and body weigh). At the sacrificed, samples from tongue (TG), cervical lymph node (CLN), donor (SBD) and recipient (SBR) small bowel were taken from all animals for histophatology and from E1 and C1l animals for IL-2, IL-4, IL-6, IL-10, IFN-gama e TNF-alfa cytokines analysis using reverse transcription polymerase chain reaction. Samples from cervical lynph nodes of 5 animals from group E2 were used for mixed lymphocyte reaction for tolerance analysis. The clinical and histophatological evolution of the disease were evaluated from degree 0 to 3 according to the severity. GVHD in E1 and E2 animals started between 84 and 115 POD. Histophatological analysis of TG and CLN showed that E1 animals present GVHD grade 2 and E2 animals grade 3. The increase of donors cells in the recipient circulation was progressive and account for 5.4± 2.3% at POD 30, 21.4±4.6% at POD 95 and 39.3±4% at POD 200. IL-4, IL-6, IL-10, IFN-gama e TNF-alfa were upregulated in CLN and IL-2, IL-6, IL-10, IFN-gama e TNF-alfa were upregulated in TG when compared with the respective controls. The lymphocytes from E2 group showed hyporeactivety to lymphocytes of normal ACI and hypereactivety to those of PVG, meaning tolerance. No cytokines alteration was noted in SBD neither SBR. Animals from group C1 and C2 did not present any sign of disease. This result show that GVHD is a inexoravel evolution under the experimental conditions of this study and the evolution of the disease is near correlated with the augmentation of the donor cells in the recipient circulation and upregulation of cytokines gene expression in target organs. Tolerance to the same donor strain lynphocytes was also noted.
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Peylhard, Mélanie. "Etude des bases moléculaires et cellulaires de la tolérance aux trypanosomoses chez les bovins par RNAseq." Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTG024.
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La Trypanosomose Animale Africaine (TAA) est une maladie parasitaire (trypanosome) à transmission vectorielle (glossine). En Afrique sub-saharienne elle constitue un obstacle majeur au développement de l’élevage. Toutefois, il existe des races bovines taurines trypanotolérantes capables de tolérer la maladie. Les races européennes et indicines sont trypanosensibles et, sans traitement, meurent généralement de l’infection. Les objectifs de thèse sont d’améliorer les connaissances sur les interactions hôtes-parasites en identifiant les gènes, les réseaux de gènes, les voies métaboliques et les fonctions biologiques associés à la trypanotolérance. Cinq races bovines ouest-africaines ont été expérimentalement infectées par Trypanosoma congolense. Des banques RNA-seq ont été réalisées à partir des échantillons sanguins pour caractériser le métatranscriptome au cours de l’infection (bovin+parasite). Les principaux résultats révèlent que l’infection a eu un impact majeur sur le transcriptome des leucocytes bovins quelle que soit la race. Les résultats confirment globalement les données issues de la littérature notamment une activation précoce de la réponse immunitaire innée, suivie d'une activation de la réponse humorale et d'une inhibition des cellules T au stade chronique de l'infection. Des résultats nouveaux ont pu être mis en évidence comme une forte perturbation du métabolisme et de la production d’énergie chez l’hôte. La race N’Dama (trypanotolérante de référence) a présenté une réponse immunitaire plus précoce et plus intense associée à une forte activation de la production d'énergie par les cellules. La race Zébu (trypanosensible de référence) a présenté une forte perturbation du métabolisme des lipides, probablement due à une spoliation par le parasite ou en lien direct avec une dérégulation du métabolisme de l’hôte. En conclusion, j’ai pu mettre en évidence des différences subtiles dans certaines voies d’activation de la réponse immunitaire, et mis en exergue les interactions entre la réponse immunitaire, des modifications métaboliques, et les perturbations induites par les parasites. Ces interactions métabolisme*réponse immunitaire mériteraient des études plus approfondies chez le bovin, pour améliorer le traitement des trypanosomoses<br>Animal African Trypanosomosis (AAT) is a parasitic disease (trypanosome) with vectorial transmission (tsetse fly). In sub-Saharan Africa, it constitutes a major impediment to livestock development. However, there are trypanotolerant taurine cattle breeds capable of tolerating the disease. European and indicine breeds are trypanosusceptible and, without treatment, usually die from infection. PhD objectives are to improve knowledge of host-parasite interactions by identifying the genes, gene networks, metabolic pathways, and biological functions associated with trypanotolerance. Five West African cattle breeds have been experimentally infected with Trypanosoma congolense. RNA-seq libraries were constructed from blood samples to characterize the metatranscriptome during infection (bovine + parasite). The main findings reveal that the infection had a major impact on the transcriptome of cattle leukocytes regardless of breed. The results generally confirm the data from the literature including early activation of the innate immune response, followed by activation of the humoral response and inhibition of T cells in the chronic stage of infection. New results could be highlighted as a strong disruption of metabolism and energy production in the host. The N'Dama (trypanotolerant reference) breed showed an earlier and more intense immune response associated with strong activation of energy production by the cells. The Zebu breed (trypanosusceptible reference) showed a strong disruption of lipid metabolism, probably due to spoliation by the parasite or directly related to deregulation of the host metabolism. In conclusion, I was able to highlight subtle differences in some pathways related to the activation of the immune response, and highlighted the interactions between immune response, metabolic changes, and parasite-induced disturbances. These interactions metabolism * immune response deserve further study in cattle, to improve the treatment of trypanosomoses
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Brännström, Åke. "Modelling animal populations." Doctoral thesis, Umeå universitet, Matematik och matematisk statistik, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-205.
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This thesis consists of four papers, three papers about modelling animal populations and one paper about an area integral estimate for solutions of partial differential equations on non-smooth domains. The papers are: I. Å. Brännström, Single species population models from first principles. II. Å. Brännström and D. J. T. Sumpter, Stochastic analogues of deterministic single species population models. III. Å. Brännström and D. J. T. Sumpter, Coupled map lattice approximations for spatially explicit individual-based models of ecology. IV. Å. Brännström, An area integral estimate for higher order parabolic equations. In the first paper we derive deterministic discrete single species population models with first order feedback, such as the Hassell and Beverton-Holt model, from first principles. The derivations build on the site based method of Sumpter & Broomhead (2001) and Johansson & Sumpter (2003). A three parameter generalisation of the Beverton-Holtmodel is also derived, and one of the parameters is shown to correspond directly to the underlying distribution of individuals. The second paper is about constructing stochastic population models that incorporate a given deterministic skeleton. Using the Ricker model as an example, we construct several stochastic analogues and fit them to data using the method of maximum likelihood. The results show that an accurate stochastic population model is most important when the dynamics are periodic or chaotic, and that the two most common ways of constructing stochastic analogues, using additive normally distributed noise or multiplicative lognormally distributed noise, give models that fit the data well. The latter is also motivated on theoretical grounds. In the third paper we approximate a spatially explicit individual-based model with a stochastic coupledmap lattice. The approximation effectively disentangles the deterministic and stochastic components of the model. Based on this approximation we argue that the stable population dynamics seen for short dispersal ranges is a consequence of increased stochasticity from local interactions and dispersal. Finally, the fourth paper contains a proof that for solutions of higher order real homogeneous constant coefficient parabolic operators on Lipschitz cylinders, the area integral dominates the maximal function in the L2-norm.
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Viennet, Elvina. "Insectes et maladies émergentes : Culicoides en région Paléarctique et leurs implications dans la transmission de la fièvre catarrhale ovine." Thesis, Montpellier 2, 2011. http://www.theses.fr/2011MON20129/document.
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La découverte du rôle des insectes en tant que vecteurs de pathogènes, établi depuis plus d'un siècle, a été l'élément moteur de la discipline « entomologie médicale et vétérinaire ». Malgré le succès de nombreuses campagnes de prévention et de programmes de lutte, nous assistons depuis une trentaine d'années à l'émergence et à la recrudescence de maladies à transmission vectorielle. Le virus de la fièvre catarrhale ovine (FCO) (Reoviridae : Orbivirus) est un très bon exemple de virus émergent en Europe dont les mécanismes de transmission sont encore peu connus dans cette région. Ce virus est transmis par des moucherons hématophages du genre Culicoides (Diptera : Ceratopogonidae) aux ruminants sauvages et domestiques. En Europe, la FCO a été pendant longtemps considérée comme une maladie exotique. À partir de 1998, plusieurs incursions apparaissent dans l'ouest du bassin méditerranéen en lien avec la remontée vers le nord de populations de Culicoides imicola, le principal vecteur afrotropical. À partir d'août 2006, l'apparition et la transmission du sérotype 8 dans le nord de l'Europe, dans des zones où C. imicola est absent, révèle l'importance des espèces autochtones et la nécessité de comprendre leur rôle vecteur. Ce travail s'intéresse aux mécanismes de transmission du virus de la FCO en Europe non méditerranéenne, en i) présentant un état de l'art de la biologie et l'écologie des Culicoides adultes, ii) en évaluant les conditions possibles d'utilisation de pièges pour estimer le taux de piqûre et iii) en décrivant les comportements trophiques pour les espèces d'intérêt vétérinaire<br>The discovery of insects as pathogens vectors was established for over a century and was the driving force behind the discipline “medical and veterinary entomology”. Despite the success of some prevention and control program campaigns, the emergence and spread of vector-borne diseases occurred dramatically during this last thirty years. Bluetongue virus (BTV) (Reoviridae: Orbivirus) is a good example of emerging virus in Europe, with a little understanding of the epidemiology of this disease. This virus is transmitted by blood-sucking midges of the genus Culicoides (Diptera: Ceratopogonidae) to wild and domestic ruminants. In Europe, BT was considered an exotic disease. In 1998, several incursions appeared in the western Mediterranean Basin in line with the northward progression of C. imicola populations, the main afrotropical vector. From August 2006, the emergence and transmission of serotype 8 in northern Europe, in areas where C. imicola is absent, revealed the importance of autochthonous species and the urgent need to understand their role as vector. This work gives new insights into the understanding of BTV transmission in northern Europe: i) presenting a state of the art review of the biology and ecology of Culicoides adults, ii) assessing different methods to study the biting rate and iii) highlighting trends in host-seeking behavior
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Nam, Bora. "EVOLUTION OF EQUINE ARTERITIS VIRUS DURING PERSISTENT INFECTION IN THE REPRODUCTIVE TRACT OF THE STALLION AND THE MALE DONKEY." UKnowledge, 2017. https://uknowledge.uky.edu/gluck_etds/34.
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Equine arteritis virus (EAV) establishes persistent infection in the stallion reproductive tract, and the carrier stallion continues to shed virus in semen for weeks to years or lifelong. The objective of this study was to elucidate the intra-host evolution of EAV during persistent infection in stallions. Seven EAV seronegative stallions were experimentally infected with EAV KY84 strain and followed for 726 days post-infection, and sequential clinical samples including semen were collected for virus isolation and next-generation sequencing (NGS). In addition, archived sequential semen samples from two stallions that were naturally infected with EAV KY84 for a long-period (up to 10 years) were also sequenced by NGS. The data demonstrated genetic bottleneck event and selection during acute infection followed by intra-host quasispecies diversification during persistent infection in the stallion reproductive tract.
Also, the full-length genome of a novel EAV donkey strain from Chile and a noncytopathic bovine viral diarrhea virus-1 (ncpBVDV-1) strain contaminating rabbit kidney-13 cells were also sequenced by NGS. The EAV donkey strain was genetically distinct but antigenically cross-reacted with EAV antisera, and it was phylogenetically closely related to the South African donkey strain of EAV. Genetic and phylogenetic analyses demonstrated that ncpBVDV-1 belongs to BVDV-1b group.
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Logan, Savannah. "Imaging Vibrio Cholerae Invasion and Developing New Tools for 3D Microscopy of Live Animals." Thesis, University of Oregon, 2019. http://hdl.handle.net/1794/24524.
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All animals harbor microorganisms that interact with each other and with their hosts. These microorganisms play important roles in health, disease, and defense against pathogens. The microbial communities in the intestine are particularly important in preventing colonization by pathogens; however, this defense mechanism and the means by which pathogens overcome it remain largely unknown. Moreover, while the composition of animal-associated microbial communities has been studied in great depth, the spatial and temporal dynamics of these communities has only recently begun to be explored.
Here, we use a transparent model organism, larval zebrafish, to study how a human pathogen, Vibrio cholerae, invades intestinal communities. We pay particular attention to a bacterial competition mechanism, the type VI secrection system (T6SS), in this process. In vivo 3D fluorescence imaging and differential contrast imaging of transparent host tissue allow us to establish that V. cholerae can use the T6SS to modulate the intestinal mechanics of its host to displace established bacterial communities, and we demonstrate that one part of the T6SS apparatus, the actin crosslinking domain, is responsible for this function.
Next, we develop an automated high-throughput light sheet fluorescence microscope to allow rapid imaging of bacterial communities and host cells in live larval zebrafish. Light sheet fluorescence microscopy (LSFM) has been limited in the past by low throughput and tedious sample preparation, and our new microscope features an integrated fluidic circuit and automated positioning and imaging to address these issues and allow faster collection of larger datasets, which will considerably expand the use of LSFM in the life sciences. This microscope could also be used for future experiments related to bacterial communities and the immune system.
The overarching theme of the work in this dissertation is the use and development of advanced imaging techniques to make new biological discoveries, and the conclusions of this work point the way toward understanding pathogenic invasion, maximizing the use of LSFM in the life sciences, and gaining a better grasp of host-associated bacterial community dynamics.
This dissertation includes previously published and unpublished co-authored material.
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MEAZZI, SARA. "THE INTERPLAY BETWEEN HOST DEFENSES AND SYSTEMIC PATHOGENS IN PROMOTING DISEASES OF COMPANION ANIMALS." Doctoral thesis, Università degli Studi di Milano, 2020. http://hdl.handle.net/2434/709076.
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Il microbiota intestinale (insieme dei microrganismi che si trovano all’interno dell’apparato gastroenterico) svolge diverse funzioni e, tra queste, di particolare interesse è il suo rapporto con il sistema immunitario. Infatti, diversi studi hanno evidenziato la presenza di disbiosi non solo in corso di patologie gastroenteriche, ma anche autoimmuni ed infettive. Gli studi in medicina veterinaria sull’argomento sono ancora pochi e proprio per questo motivo, all’interno di questo progetto, è stato scelto di indagare la possibile relazione tra il microbiota intestinale e due particolari patologie infettive (la peritonite infettiva felina -FIP- e la leishmaniosi canina) la cui patogenesi è fortemente influenzata dal tipo di risposta immunitaria sviluppata dall’ospite. Gli scopi di questo progetto sono quindi stati: la valutazione del microbiota intestinale in gatti affetti o meno da FIP (studio I). Dal momento che diagnosi in vivo di FIP risulta spesso difficoltosa, è stato valutato il potenziale, come biomarker di FIP, della paraoxonasi-1, una proteina di fase acuta negativa fortemente influenzata da importanti stati ossidativi (studi II e III). Per lo stesso motivo è stata valutata la correlazione tra le performance diagnostiche di istopatologia, immunoistochimica e RT-PCR su differenti organi (studio IV). Infine, è stata indagata la composizione del microbiota intestinale in cani infetti o meno da Leishmania spp., correlando i risultati ottenuti con le differenti popolazioni leucocitarie valutate mediante citofluorimetria (studi V e VI). I risultati ottenuti da questo progetto hanno fornito delle indicazioni preliminari sulla composizione del microbiota intestinale in gatti affetti da FIP o positivi per Coronavirus, che necessitano però un approfondimento su un gruppo di studio più ampio (studio I). È stato possibile determinare gli intervalli di riferimento della paraoxonasi-1 nel gatto ed evidenziare le sue buone performance come marker diagnostico in corso di FIP (studi II e III). Nonostante l’immunoistochimica rimanga il gold standard per la diagnosi di FIP, l’associazione con RT-PCR potrebbe ridurre gli errori diagnostici, vista la buona correlazione tra le due metodiche (studio IV). Infine, la valutazione della composizione del microbiota e delle popolazioni leucocitarie in cani affetti da leishmaniosi ha messo in luce delle differenze significative sia rispetto ai cani sani, che agli esposti asintomatici. Questi risultati sono incoraggianti e possono fungere da punto di partenza per ulteriori indagini (studi V e VI).<br>The gut microbiota (consortium of all the microorganisms that inhabit the gastrointestinal tract) plays different roles in the host. Among these, its relationship with the immune system has been of great interest in the last few years. Indeed, several studies highlight the presence of dysbiosis not only in gastrointestinal diseases, but also during autoimmune or infectious diseases. Literature about this topic is scarce in veterinary medicine. Thus, in this project, the possible relationship between gut microbiota and two specific diseases (feline infectious peritonis -FIP- and canine leishmaniasis) was investigated. These diseases were chosen due to the pivotal role of the immune response in their pathogenesis. The aims of this projects were: the evaluation of gut microbiota of cats with and without FIP (study I). Since in vivo diagnosis of FIP is quite challenging, the potential role of paroxonase-1 (a negative acute phase protein strongly influenced by oxidation) as a biomarker of FIP was investigated (studies II-III). For the same reason, the diagnostic agreement among histopathology, immunohistochemistry and RT-PCR on different organs was evaluated (study IV). Finally, the gut microbiota composition in dogs infected or not by Leishmania spp. was investigated. The results were correlated with the leukocyte populations studied by flow cytometry (studies V-VI). Results obtained in this project provided preliminary data about gut microbiota composition in cats affected by FIP or only Coronavirus positive. This achievement needs to be further investigated on a bigger sample size (study I). Paraoxonase-1 reference interval and its good performance as a diagnostic biomarker of FIP were determined (studies II-III). Despite the immunohistochemistry is still the gold standard for FIP diagnosis, the good diagnostic agreement obtained in the study suggested that a possible association with RT-PCR could minimize diagnostic errors (study IV). Finally, the gut microbiota composition and leukocyte populations of leishmaniotic dogs highlighted some significant differences compared with both healthy and exposed asymptomatic dogs. These promising results could be a starting point for further researches (studies V-VI).
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Henriksson, Annette. "Relationen mellan aktiviteter med hästar och psykosocial utveckling hos barn med autismdiagnos : En kvalitativ studie av föräldrars erfarenheter." Thesis, Ersta Sköndal högskola, S:t Lukas utbildningsinstitut, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:esh:diva-5475.
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Denna studie har genomförts i syfte att öka kunskapen om psykosocial utvevckling hos barn med autismdiagnos i relation till aktiviteter med hästar. Studien är kvalitativ, baserad på fem intervjuer av föräldrar och det ingår fältobservationer. Intervjuerna har bearbetats enligt induktiv tematisk analys och redovisas under tre teman relaterade till barnens samspel med sin omvärld. Resultatet visar att aktiviteten med hästar inverkar positivt på barnens vilja och förmåga att samspela och kommunicera med omvärlden. Färdigheterna visar sig i samspel med barn såväl som med vuxna, både inom familjen och i andra sammanhang. Studiens resultat visar överensstämmelse med tidigare forskning, samt att aktivitetens mångfassetterade innehåll och effekter synliggörs. Resultat som överraskar är erfarenheter av barnens annorlunda relation och kommunikation med hästar, samt iakttagelser av ridningens omedelbara effekter på barnen. Forskning föreslås ur ett familjeperspektiv där barnets röst lyfts fram, samt fortsatt forskning på ridningens fysiologiska effekter i relation till socialt interagerande.<br>This study has been conducted in order to increase knowledge about psychosocial development in children with autism diagnosis in relationship to activities with horses. The study is qualitative, based on five interviews with parents and includes field observations. The interviews have been processed according to inductive thematic analysis and are reported under three themes related to the childrens interaction with their environment. The result shows that the activity with horses has positive impact on the children's desire and ability to interact and communicate with the outside world. The skills manifests in interaction with children as well as with adults, both within the family and in other settings. The result of the study indicates conformity with previous research, and the event's multi-facetted content and effects are made visible. Surprising results are experiences of the children's different relationship and communication with horses, and observations of the immediate impact on the children when riding. Research from a family perspective highligtening the voice of the child is proposed, as well as further research on physiological effects of horseback riding in reltionship to social interacting.
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Delannoy, Christian M. J. "Host adaptation of aquatic Streptococcus agalactiae." Thesis, University of Stirling, 2013. http://hdl.handle.net/1893/17259.
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Streptococcus agalactiae is a pathogen of multiple hosts. The bacterium, an aetiological agent of septicaemia and meningo-encephalitis in freshwater and saltwater fish species, is considered a major threat to the aquaculture industry, particularly for tilapia. Cattle and humans are however the main known reservoirs for S. agalactiae. In humans, the bacterium (commonly referred to as Group B Streptococcus or GBS) is a member of the commensal microflora of the intestinal and genito-urinary tracts, but it is also a major cause of neonatal invasive disease and an emerging pathogen in adults. In cattle, S. agalactiae is a well-recognized causative agent of mastitis. Numerous studies focusing on S. agalactiae from human and bovine origins have provided insight into the population structure of the bacterium, as well as the genome content and pathogenic mechanisms through identification of virulence determinants. Concerning S. agalactiae from aquatic origins, scientific information mainly focused on case reporting and/or experimental challenges, with a limited or absence of information in terms of pathogenesis, virulence determinants and genotypes of the strains involved. The objective of this study was to enhance our understanding of the molecular epidemiology, host-adaptation and pathogenicity of S. agalactiae in aquatic species, with particular emphasis on tilapia. Firstly, a collection of 33 piscine, amphibian and sea mammal isolates originating from several countries and continents was assembled, with the aim of exploring the population structure and potential host specificity of aquatic S. agalactiae. Isolates were characterised using pulsed-field gel electrophoresis (PFGE), multi-locus sequence typing (MLST), and a standardised 3-set genotyping system comprising molecular serotypes, surface protein gene profiles and mobile genetic element profiles. Two major subpopulations were identified in fish. The first subpopulation consisted of non-haemolytic isolates that belonged to sequence type (ST) 260 or 261, which are STs that have been reported only from teleosts. These isolates exhibited a low level of genetic diversity by PFGE and clustered with other STs that have been reported only in fish. Another common feature was the absence of all surface protein genes or mobile genetic elements targeted as part of the 3-set genotyping and that are usually found in human or bovine isolates. The second subpopulation consisted of β-haemolytic isolates recovered from fish, frogs and sea mammals, and that exhibited medium to high genetic diversity by PFGE. STs identified among these isolates have previously been identified from strains associated with asymptomatic carriage and invasive disease in humans. The human pathogenic strain ST7 serotype Ia was detected in fish from Asia. Moreover, ST283 serotype III-4 and its novel single locus variant ST491 detected in fish from Southeast Asia shared a 3-set genotype identical to that of an emerging ST283 clone associated with invasive disease of adult humans in Asia. These observations suggested that some strains of aquatic S. agalactiae may present a zoonotic or anthroponotic hazard. STs found among the seal isolates (ST23) have also been reported from humans and numerous other host species, but never from teleosts. This work provided an excellent basis for exploration of the virulence of selected strains in experimental challenges. The virulence of two strains of S. agalactiae was experimentally investigated by intra-peritoneal infection of Nile tilapia (Oreochromis niloticus), using an isolate originally recovered from fish and belonging to ST260, and an isolate originating from a grey seal and belonging to ST23. The clinical signs, the in vivo distribution of viable bacteria and bacterial antigens, and the gross and histopathological lesions that developed during the time course of the infection were investigated. The ST260 strain was highly virulent, whereas no major clinical sign or mortalities occurred in the fish challenged with the ST23 strain. After injection, both strains however gained access to the bloodstream and viable bacteria were recovered from all organs under investigation. During the early stages of infection, bacteria were mostly found within the reticulo-endothelial system of the spleen and kidney. Thereafter, the ST260 demonstrated a particular tropism for the brain and the heart, but granulomatous inflammation and associated necrotic lesions were observed in all organs. ST23 was responsible for a mixed inflammatory response associated with the presence of bacteria in the choroid rete and in the pancreatic tissue only. After 7 days post-challenge and for both strain, the formation or containment of bacteria within granulomata or other encapsulated structures appeared to be a major component of the fish response. However, the load of viable bacteria remained high within organs of fish infected with ST260, suggesting that, unlike ST23, this strain is able to survive within macrophages and/or to evade the immune system of the fish. This work demonstrates that the lack of report of ST23 strains in fish is possibly not due to a lack of exposure but to a lack of virulence in this host. The two strains, which differ in prevalence and virulence in fish, provide an excellent basis to investigate genomic differences underlying the host-association of distinct S. agalactiae subpopulations. The genome of the ST260 strain used in challenge studies was sequenced. We therefore provided the first description for the genome sequence of a non-haemolytic S. agalactiae isolated from tilapia (strain STIR-CD-17) and that belongs by multi-locus sequence typing (MLST) to clonal complex (CC) 552, which corresponds to a presumptive fish-adapted subgroup of S. agalactiae. The genome was compared to 13 S. agalactiae genomes of human (n=7), bovine (n=2), fish (n=3) and unknown (n=1) origins. Phylogenetic analysis based on the core genome identified isolates of CC552 as the most diverged of all S. agalactiae studied. Conversely, genomes from β-haemolytic isolates of CC7 recovered from fish were found to cluster with human isolates of CC7, further supporting the possibility that some strains may represent a zoonotic or anthroponotic hazard. Comparative analysis of the accessory genome enabled the identification of a cluster of genes uniquely shared between CC7 and CC552, which encode proteins that may provide enhanced fitness in specific niches. Other genes identified were specific to STIR-CD-17 or to CC552 based on genomic comparisons; however the extension of this analysis through the PCR screening of a larger population of S. agalactiae suggested that some of these genes may occasionally be present in isolates belonging to CC7. Some of these genes, occurring in clusters, exhibited typical signatures of mobile genetic elements, suggesting their acquisition through horizontal gene transfer. It is not possible to date to determine whether these genes were acquired through intraspecies transfer or through interspecies transfer from the aquatic environment. Finally, general features of STIR-CD-17 highlighted a distinctive genome characterised by an absence of well conserved insertion sequences, an abundance of pseudogenes, a smaller genomic size than normally observed among human or bovine S. agalactiae, and an apparent loss of metabolic functions considered conserved within the bacterial species, indicating that the fish-adapted subgroup of isolates (CC552) has undergone niche restriction. Finally, genes encoding recognised virulence factors in human S. agalactiae were selected and their presence and structural conservation was evaluated within the genome of STIR-CD-17.
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Watson, Michael Bryan. "Bioinformatic analysis of genome-scale data reveals insights into host-pathogen interactions in farm animals." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/19540.
Full textAbstract:
This thesis documents the contribution of my bioinformatics research activities, including novel software development, to a range of research projects aimed at investigating the interactions between bacterial and viral pathogens and their hosts. The focus is largely on farm animal species and their pathogens, although some of the research has a wider scientific impact. RNA interference (RNAi) refers to a variety of related regulatory pathways present in animals, plants and insects. The major pathways are microRNAs (miRNAs), small-interfering RNAs (siRNAs) and PIWI-interacting RNAs (piRNAs). Marek’s disease virus is an important pathogen of poultry, causing T-cell lymphoma. We identified the presence and expression patterns of several MDV-encoded microRNAs, including the identification of 5 novel microRNAs. We also showed that not only do virus-encoded microRNAs dominate the mirNome within chicken cells, but also that specific host-microRNAs are down-regulated. We also identify novel virus-encoded microRNAs in other Herpesviridae and provide the first evidence of miRNA evolution by duplication in viruses. In related work, we present a novel microRNA generated by the canonical miRNA biogenesis pathway in Avian Leukosis Virus, another avian oncogenic virus, and publish data showing the expression pattern of known chicken microRNAs across a range of important avian cells. Two of the other RNAi pathways (siRNA and piRNA) form an important part of the antiviral response in arthropods. We have published work demonstrating an siRNA antiviral response to bluetongue virus and Schmallenberg virus in cells from the Culicoides midge, an important insect vector, as well as work demonstrating the importance of the piRNA pathway in the antiviral response to Semliki forest virus (SFV). Further work on flaviviruses in ticks demonstrates the active suppression of the siRNA response by Langat Virus, as well as a key difference between the siRNA responses in Mosquitos compared to ticks. Salmonella is one of the most important zoonoses, with an estimated 1.4 million cases of human salmonellosis per annum in the USA alone. Salmonella infections of farm animals are an important route into the human food chain. This thesis presents work on the comparative structure and function of 13 fimbrial operons within Salmonella enterica serovar Enteritidis as well as a genomic comparison of that serovar with Salmonella enterica serovar Gallinarum, a chicken-specific serovar. We characterised the global expression profile of Salmonella enterica serovar Typhimurium during colonization of the chicken intestine, and we have published the genomes of four strains of Salmonella eneterica serovars of well-defined virulence in food-producing animals. Our work in this area led to us publishing an important and comprehensive review of the automatic annotation of bacterial genomes. Finally, I present work on novel software development. ProGenExpress, a software tool that allows the easy and accurate integration and visualisation of quantitative data with the genome annotation of bacteria; Meta4 is a web application that allows data sharing of bacterial genome annotations from metagenomes; CORNA, a software tool that allows scientists to link together microRNA targets, gene expression and functional annotation; viRome, a software tool for the analysis of siRNA and piRNA responses in virus-infection studies; DetectiV, a software tool for the analysis of pathogen-detection microarray data; and poRe, a software tool that enables users to organise and analyse nanopore sequencing data.
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Richards, David Trevor. "The epidemiology of the ascarid nematode Toxocara canis and other intestinal helminths in the red fox (Vulpes vulpes)." Thesis, Royal Holloway, University of London, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243254.
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Savini, Federica <1985>. "Host Jump in BPVs: is Species- Specificity Still Appropriate for Papillomaviruses?" Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7639/2/Tesi_dottorato_Savini_31.3.16.pdf.
Full textAbstract:
Into the family Papillomaviridae, four different genera Delta Epsilon Xi and Dyoxi include the fifteen Bovine Papillomaviruses (BPVs) that have been characterized so far in cattle, even though it has been estimated that type number may exceed 20. Current classification system assumes that the host species in which a PV was firstly detected, is the original host, and the identified types are therefore named after it. Papillomaviruses (PVs) are indeed generally considered to be highly specific for their hosts; however, within the Delta-PVs, BPV types 1, 2 and 13 are well recognized to infect multiple species. Our results deepen the knowledge on circulation of BPV types in Italy and further contribute to a better understanding on their intra-genus variability. Besides observing that BPVs can contribute to the spread of other epitheliotropic viruses, we confirmed the host-jumping ability of the Delta PVs.
The presence of co-infections between BPVs belonging to Delta and Xi genera in the healthy skin and mucosa of chamois and deer strongly suggest the reservoir role of wild ruminants belonging to the Bovidae and Cervidae families for domestic ruminant PVs.
Furthermore, we identified the Eqsarc1 variant in healthy subjects and in non-equid species, suggesting an “equine adaptation” of the virus variant.