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Articoli di riviste sul tema "Plasmodium falciparum – Research"
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Maslachah, Lilik, Yoes Prijatna Dachlan, Chairul A. Nidom e Loeki Enggar Fitr. "Experimental Models Point Mutations In Plasmodium falciparum pfatpase6 Gene Exposed to Recuring Artemisinin In Vitro". KnE Life Sciences 3, n. 6 (3 dicembre 2017): 422. http://dx.doi.org/10.18502/kls.v3i6.1151.
Testo completoAbstract (sommario):
The aims of this research to prove that repeated exposure of artemisinin can cause pfatpase6 gene mutation on Plasmodium falciparum in vitro. The research methods used culture In Vitro Plasmodium falciparum of strain 2300 IC50 value determination test artemisinin, artemisinin repeated exposure test (PO1, PO2, PO3 dan PO4) dose IC50, DNA extraction, gene amplification of pfatpase6 using Polymerase Chain Reaction (PCR) technique, electrophoresis, PCR product purification, labeling DNA from PCR results, DNA precipitation of PCR product, application of product labeling on the sequencing machines, analysis of the results of sequencing, and Data Analysis. The results of PCR pfatpase6 gene amplification include region 6 – 3216 for codon 89-1031 located in exon 1 and 2 Plasmodium falciparum 2300 by using five pairs of primers. Primer pair 1FR produce a long amplicon of 737 bp which covers of codon 89; primer pair 2FR produce a long amplicon of 813 bp which covers of codon 263, 431; primer pair 4FR produce a long amplicon of 700 bp which covers of codon 460, 465, 623; primer pair 5FR produce a long amplicon of 550 bp which includes of codon 683, 769; and primer pair 6FR produce a long amplicon of 876 bp which covers of codon 898, 1031.Multialigment pfatpase6 gene Plasmodium falciparum of strains Papua 2300 point mutations are obtained in the form of transition and transversion in treatment groups at the same nucleotide region 123, 2035, 2043, 2138 dan 2148. Conclusion of this research Artemisinin repeated exposure can cause point mutations in pfatpase6 genes Plasmodium falciparum of strains 2300 in vitro Keyword: Artemisinin, Plasmodium falciparumof strain Papua 2300, pfatpase6 gene, point mutation
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Rina A. Mogea. "PLASMODIUM DOMINAN DALAM NYAMUK ANOPHELES BETINA (Anopheles spp.) PADA BEBERAPA TEMPAT DI DISTRIK MANOKWARI BARAT". Jurnal Natural 14, n. 1 (1 aprile 2018): 29–36. http://dx.doi.org/10.30862/jn.v14i1.13.
Testo completoAbstract (sommario):
Malaria contagious by mosquito Anopheles Betina bringing protozoa parasite in its body (Plasmodium). Plasmodium there are four specieses that is Plasmodium vivax, Plasmodium ovale, Plasmodium malariae and Plasmodium falciparum, but often becomes pathogen that is Plasmodium vivax and Plasmodium falciparum. As for intention of this research is to identify Plasmodium which is dominant at female Anopheles mosquito (Anopheles spp.) and knows distribution pattern of female Anopheles mosquito (Anopheles spp.) in some places in Districts Manokwari Barat.
Based on research result done to four locations that is area Amban, Wosi, Sanggeng and Kota is found [by] 1024 mosquito tails. From the amounts only 115 mosquito tails was mosquito Anopheles Betina while the other is mosquito Anopheles male, mosquito Culex and Aedes. Mosquito Anopheles Betina found consisted of 4 species that is Anopheles bancrofti, Anopheles kochi, Anopheles farauti and Anopheles koliensis.
Mosquito Anopheles Betina which is dissected, obtained 2 the Plasmodium species in mosquito spit gland is Plasmodium vivax and Plasmodium falciparum, and from calculation by index dominant can be told that both types of this very dominant Plasmodium in Districts Manokwari Barat because its the dominant index > 5%.
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Dominique, Tano Konan, Koffi Akissi Jeanne, Dablé Marius Tresor, Silué Kigbafori Dieudonné, Tuo Karim, Nkoua Badzi Cynthia, Bénié Edjronké Marc Alexis, Yéo Issa, Menan Eby Ignace Hervé e Yavo William. "Improved Protocol for Continuous Culture of Plasmodium falciparum Reference Strains". Journal of Pure and Applied Microbiology 15, n. 1 (1 febbraio 2021): 123–29. http://dx.doi.org/10.22207/jpam.15.1.07.
Testo completoAbstract (sommario):
Parasitic biobank of Plasmodium falciparum is almost germinal in Côte d’Ivoire. However, several high-level research topics on this parasite involve the taking into account of nature isolates but also chemo-sensitive or resistant reference strains for a better validation of results. In addition, acquisition of these reference strains is still arduous for laboratories in developing countries due to complexity of administrative procedures. For those reasons, this study aimed in to combine several procedures into a consolidated one in order to enhance the multiplication of P. falciparum reference strains. Continuous culture of plasmodial strains was based on the Trager and Jensen procedures. The CELL culture protocols used are those of the Swiss TPH described by Sergio Wittlin; the “Growing Plasmodium falciparum cultures at high parasitemia” and the “Stockholm sorbitol method” of Methods in Malaria Research-6th edition 2013; and the INV-01 and INV-02 procedures of the Worldwide Antimalarial Resistance Network (WWARN). Reference Plasmodium falciparum strains NF54 sensitive to chloroquine (CQs) and K1 resistant to chloroquine (CQr) were received from the Swiss Tropical Institute and Public Health (Swiss TPH). The CQs NF54 strain reacted more quickly to the protocol unlike the CQr K1 strain. Parasitic densities (DP) obtained with NF54 strain were ranged from 0.4% at day zero (D0) to 11.4% at day eight (D8). Strain K1 finally adapted successfully after one month of follow-up. Related DPs ranged from less than 0.1% to more than 20% in just three growth cycles after adaptation. A joint protocol (from this work) called “CRLP-SwissTPH-Pasteur_001” is available and allows to efficiently multiply reference strains NF54 and K1. It is planned to spread out the tests to other plasmodial strains as well as to wild isolates in order to standardize this procedure.
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Guggisberg, Ann M., Rachel E. Amthor e Audrey R. Odom. "Isoprenoid Biosynthesis in Plasmodium falciparum". Eukaryotic Cell 13, n. 11 (12 settembre 2014): 1348–59. http://dx.doi.org/10.1128/ec.00160-14.
Testo completoAbstract (sommario):
ABSTRACTMalaria kills nearly 1 million people each year, and the protozoan parasitePlasmodium falciparumhas become increasingly resistant to current therapies. Isoprenoid synthesis via the methylerythritol phosphate (MEP) pathway represents an attractive target for the development of new antimalarials. The phosphonic acid antibiotic fosmidomycin is a specific inhibitor of isoprenoid synthesis and has been a helpful tool to outline the essential functions of isoprenoid biosynthesis inP. falciparum. Isoprenoids are a large, diverse class of hydrocarbons that function in a variety of essential cellular processes in eukaryotes. InP. falciparum, isoprenoids are used for tRNA isopentenylation and protein prenylation, as well as the synthesis of vitamin E, carotenoids, ubiquinone, and dolichols. Recently, isoprenoid synthesis inP. falciparumhas been shown to be regulated by a sugar phosphatase. We outline what is known about isoprenoid function and the regulation of isoprenoid synthesis inP. falciparum, in order to identify valuable directions for future research.
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Rahmanti, Farah Zakiyah, Novita Kurnia Ningrum, Septian Enggar Sukmana e Prajanto Wahyu Adi. "Plasmodium Falciparum Identification in Thick Blood Preparations Using GLCM and Support Vector Machine (SVM)". Journal of Applied Intelligent System 2, n. 1 (21 aprile 2017): 12–20. http://dx.doi.org/10.33633/jais.v2i1.1388.
Testo completoAbstract (sommario):
Malaria is one of the serious diseases that require rapid handling, otherwise it can lead to death. One of the causes of malaria parasites is plasmodium falciparum which can cause severe or fatal malaria. Handling a medical late can increase the risk of death. Therefore, it takes a rapid identification system with a high percentage of accuracy to reduce the risk of death. This research aims to build an identification system of plasmodium falciparum in thick blood film using Gray Level Co-occurrence Matrix (GLCM) and Support Vector Machine (SVM). The GLCM is used to get texture feature values such as contrast, correlations, energy, and homogeneity from images. Those values is processed and as an input of classification using SVM. The research result using SVM for accuracy value of plasmodium falciparum identification can reach 93.33%.
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Mu, Jianbing, Karl B. Seydel, Adam Bates e Xin-Zhuan Su. "Recent Progress in Functional Genomic Research in Plasmodium falciparum". Current Genomics 11, n. 4 (1 giugno 2010): 279–86. http://dx.doi.org/10.2174/138920210791233081.
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VERONICA, ELVINA, e NI KADEK SINTA DWI CHRISMAYANTI. "Potensi Daun Kastuba (Euphorbia Pulcherrima) Sebagai Antimalaria Plasmodium Falciparum". Hang Tuah Medical Journal 18, n. 1 (20 novembre 2020): 1. http://dx.doi.org/10.30649/htmj.v18i1.466.
Testo completoAbstract (sommario):
<p><strong>Abstract</strong></p><p><strong>Introduction:</strong> Around 41% of people in the world at risk of malaria due to plasmodium infection. <em>Plasmodium falciparum</em> is the most dangerous malaria infection compared to another plasmodium because it causes 90% of malaria deaths. ACT (Artemisinin Combination Therapy) is the goal standard of malaria medicine, is starting to become resistant, so other alternatives are needed. Poinsettia plants (<em>Euphorbia pulcherrima</em>) are ornamental plants and contain compounds that potential as anti-parasites.</p><p><strong>Objective:</strong> To aims the potential of poinsettia leaves as an antimalarial alternative to <em>Plasmodium falciparum</em> in malaria treatment.</p><p><strong>Methods:</strong> Literature studies using in vivo, in vitro, in silico research articles, and literature reviews from national and international journals accessed from Google Scholar, Elsevier, Science Direct, and Pubmed in the last 10 years using malaria, antioxidants, anti-malaria, <em>Plasmodium falciparum</em>, and <em>Euphorbia pulcherrima</em> as keywords. There were 22 relevant articles used in this literature review.</p><p><strong>Results:</strong> Antioxidants in poinsettia leaves inhibited plasmodium growth by inhibit nutrient transport at new permeation pathways and prevent hemozoin ban. Terpenoids in poinsettia inhibit schizont and trophozoite in an earlier asexual phase of <em>Plasmodium falciparum</em> by inhibiting isoprenoid biosynthesis.</p><p><strong>Conclusion:</strong> Poinsettia (<em>Euphorbia pulcherrima</em>) has the potency to be an antimalarial alternative against <em>Plasmodium falciparum</em>. Need further research about the dosage and side effects of the usage.</p><p><strong>Key words:</strong> Malaria, antioxidants, anti-malaria, <em>Plasmodium falciparum</em>, <em>Euphorbia pulcherrima</em></p><p><strong>Abstrak</strong></p><p><strong>Pendahuluan:</strong> Sebesar 41% penduduk di dunia berisiko terkena malaria akibat infeksi plasmodium. Infeksi malaria akibat <em>Plasmodium falciparum</em> merupakan infeksi paling berbahaya dibandingkan plasmodium lainnya karena menyebabkan 90% kematian malaria. obat malaria ACT (<em>Artemisinin Combination Therapy</em>) yang merupakan pengobatan goal standar obat malaria kini mulai resistensi sehingga diperlukan alternatif lainnya. Tanaman kastuba (<em>Euphorbia pulcherrima</em>) merupakan tanaman hias dan memiliki kandungan senyawa antioksidan yang berpotensi sebagai anti parasit.</p><p><strong>Tujuan</strong>: mengetahui potensi daun kastuba sebagai alternatif antimalarial <em>Plasmodium falciparum</em> dalam pengobatan malaria.</p><p>Metode: Studi literatur menggunakan artikel penelitian in vivo, in vitro, in silico, dan artikel tinjauan pustaka dari jurnal nasional dan internasional yang diakses dari Google Scholar, Elsevier, Science Direct, dan Pubmed 10 tahun terakhir menggunakan kata kunci malaria, antioksidan, anti-malaria, <em>Plasmodium falciparum</em>, <em>Euphorbia pulcherrima</em>. Digunakan 22 artikel yang relevan dalam <em>literature review</em> ini.</p><p><strong>Hasil:</strong> Antioksidan tanaman kastuba menghambat perkembangan plasmodium dengan menghambat transport nutrisi jalur permeasi baru dan mencegah pembentukan hemozoin. Terpenoid dalam tanaman kastuba menghambat pembentukan skizon dan tropozoit fase aseksual <em>Plasmodium falciparum</em> dengan menghambat biosintesis isoprenoid.</p><p><strong>Kesimpulan:</strong> Tanaman kastuba (<em>Euphorbia pulcherrima</em>) berpotensi sebagai alternatif antimalarial terhadap <em>Plasmodium falciparum</em>. Perlu penelitian lebih lanjut terutama dalam dosis dan efek samping penggunaannya.</p><p><strong>Kata kunci</strong>: Malaria, antioksidan,<em> anti-malaria, Plasmodium falciparum, Euphorbia pulcherrima </em></p>
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Trager, William, e James B. Jensen. "Continuous culture of Plasmodium falciparum: its impact on malaria research". International Journal for Parasitology 27, n. 9 (settembre 1997): 989–1006. http://dx.doi.org/10.1016/s0020-7519(97)00080-5.
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Erawati, Deasy, Febriza Dwiranti e Rina Anita Mogea. "Prevalansi Malaria di Puskesmas Sanggeng Kabupaten Manokwari Periode November sampai Desember 2019". BIOSAINTROPIS (BIOSCIENCE-TROPIC) 6, n. 2 (25 gennaio 2021): 72–77. http://dx.doi.org/10.33474/e-jbst.v6i2.377.
Testo completoAbstract (sommario):
Malaria is a disease caused by parasitic infection, named Protozoa from the genus Plasmodium which is transmitted to humans by the bite of Anopheles mosquito. Manokwari Regency, which is located in West Papua Province, is a high malaria endemic area with Annual Parasite Incidence (API) 22.88 in 2018, this numbers is included in the High Case Incidence (HCI)> 5 category. The aim of this study is to analyze malaria cases in patients who treated at Sanggeng Public Health Center from November to December 2019 based on; the number of cases, patient characteristics (age group and gender) and type of Plasmodium. This research method is descriptive with a laboratory approach, namely microscopic examination of thin and thick blood preparations using a microscope. The results of the study of 730 patients, there were 35 malaria positive blood supplies. The highest prevalence of people with malaria were aged ≥ 15 years (51.42%). Most of the patients with malaria based on gender were women (51.43%) and the types of plasmodium found were Plasmodium falciparum (20%) and Plasmodium vivax (80%).
Keywords: Plasmodium falciparum, Plasmodium vivax, Anopheles, malaria endemic
ABSTRAK
Malaria merupakan penyakit yang disebabkan infeksi parasit yaitu Protozoa dari genus Plasmodium yang ditular pada manusia oleh gigitan nyamuk Anopheles. Kabupaten Manokwari yang berada di wilayah Provinsi Papua Barat merupakan daerah endemis tinggi malaria dengan Annual Parasite Incidence (API) 22,88 tahun 2018, angka ini termasuk dalam kategori High Case Incidence (HCI) > 5. Tujuan penelitian ini yaitu menganalisis kasus malaria pada pasien yang berobat di Puskemas Sanggeng dari bulan November sampai Desember 2019 . Berdasarkan jumlah kasus, karakteristik pasien (berdasarkan kelompok umur dan jenis kelamin) dan jenis Plasmodium. Metode penelitian ini adalah deskriptif dengan pendekatan laboratorium yaitu pemeriksaan secara mikroskopik sediaan darah tipis dan sediaan darah tebal menggunakan mikroskop. Hasil penelitian dari 730 pasien terdapat 35 sedian darah positif malaria. Prevalensi usia yang kena malaria paling tinggi pada usia ≥ 15 tahun (51,42 %). Penderita malaria berdasarkan jenis kelamin terbanyak adalah perempuan (51,43 %) dan jenis plasmodium yang ditemukan adalah Plasmodium falciparum (20%) dan Plasmodium vivax (80%).
Kata kunci: Plasmodium falciparum, Plasmodium vivax, Anopheles, endemis malaria
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Maslachah, Lilik, Yoes Prijatna Dachlan, Chairul A. Nidom e Loeki Enggar Fitri. "Induction of Plasmodium falciparum strain 2300 dormant forms by artemisinin". Universa Medicina 34, n. 1 (26 febbraio 2016): 25. http://dx.doi.org/10.18051/univmed.2015.v34.25-34.
Testo completoAbstract (sommario):
BACKGROUND The presence of Plasmodium falciparum resistance and decreased efficacy of artemisinin and its derivatives has resulted in the issue of malaria becoming increasingly complex, because there have been no new drugs as artemisinin replacements. The aims of this research were to evaluate in vitro changes in ultrastructural morphology of P. falciparum 2300 strain after exposure to artemisinin. METHODS The research used an experimental design with post test only control group. Cultures of P. falciparum 2300 strain in one control and one mutant group were treated by exposure to artemisinin at IC50 10-7 M for 48 hours. Ultrastructural phenotypic examination of ring, trophozoite and schizont morphology and developmental stage in the control and mutant group were done at 0, 12, 24, 36, 48 hours by making thin blood smears stained with 20% Giemsa for 20 minutes and examined using a microscope light at 1000x magnification. RESULTS Dormant forms occurred after 48 hours of incubation with IC50 10-7 M artemisinin in the control group. In the mutant group, dormant forms, trophozoites with blue cytoplasm and normal schizont developmental stages were seen. Ultrastructural phenotypic morphology at 0, 12, 24, 36, 48 hours showed that in the control group dormant formation already occurred with exposure to IC50 10-7 M, while in the mutant group dormant formation occurred only with exposure to IC50 2.5x10-5 M. CONCLUSION Exposure to artemisinin antimalarials in vitro can cause phenotypic morphological changes of dormancy in P. falciparum Papua 2300 strain.
Tesi sul tema "Plasmodium falciparum – Research"
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Birkholtz, Lyn-Marie. "Functional and structural charaterization of the unique bifunctional enzyme complex involved in regulation of polyamine metabolism in Plasmodium falciparum". Thesis, University of Pretoria, 2001. http://hdl.handle.net/2263/25944.
Testo completoAbstract (sommario):
Malaria remains one of the most serious tropical infectious diseases affecting mankind. The prevention of the disease is hampered by the increasing resistance of the parasite to existing chemotherapies. The need for novel therapeutic targets and drugs is therefore of the utmost importance and detailed knowledge of the biochemistry of the parasite is imperative. This study was directed at the biochemical characterisation of the polyamine metabolic pathway of P. falciparum in order to elucidate differences between the parasite and its human host that can be exploited in the design of novel antimalarials. The thesis focussed on the two rate-limiting enzymes in polyamine biosynthesis, S¬adenosylmethionine decarboxylase (AdoMetDC) and ornithine decarboxylase (ODC), which occur as a unique bifunctional complex in P. falciparum. The genomic structure of the bifunctional gene indicated a single, monocistronic transcript with large untranslated regions that were predicted to be involved in unique translational regulatory mechanisms. This gives rise to a bifunctional protein containing both decarboxylase activities on a single polypeptide forming a heterotetrameric complex. Activity of the decarboxylases decreases dramatically if these proteins are expressed in their monofunctional forms as homodimeric ODC and heterotetrameric AdoMetDC. The deduced amino acid sequence indicated that all the essential residues for catalysis are conserved and highlighted the presence of three parasite-specific insertions. The parasite-specific inserts were shown to be essential for the catalytic activity of the respective domains and also to influence the activity of the neighbouring domain, indicating that intramolecular communication exists in the heterotetrameric complex. The most structured and smallest insert was also shown to mediate protein-protein interactions between the two domains and to stabilise the complex. Further structure- functional characterisations of specifically the ODC domain were deduced from a comparative homology model. The model predicted an overall structure corresponding to those of other homologous proteins. The validity of the model is supported by mutagenesis results. However, certain parasite-specific properties were identified in the active site pocket and dimerisation interface. The former was exploited in the rational design of novel putative ODC inhibitors directed only against the P. falciparumprotein by in silico screening of chemical structure libraries. This study therefore describes the identification of certain parasite-specific properties in a unique bifunctional protein involved in regulation of polyamine metabolism of P. falciparum. Such discoveries are invaluable in strategies aimed at elucidating biochemical and metabolic differences between the parasite and its human host that could be exploited in the design of alternative, parasite-specific chemotherapies. Moreover, the thesis also contributed new knowledge on certain less well-understood biological phenomena characteristic of P. falciparum, the nature and origin of bifunctional proteins and the functional properties of parasite-specific inserts found in some proteins of the parasite.Thesis (PhD (Biochemistry))--University of Pretoria, 2002.
Biochemistry
unrestricted
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Daniyan, Michael Oluwatoyin. "The plasmodium falciparum exported Hsp40 co-chaperone, PFA0660w". Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1011780.
Testo completoAbstract (sommario):
Plasmodium falciparum is the pathogen that is responsible for the most virulent, severe and dangerous form of human malaria infection, accounting for nearly a million deaths every year. To survive and develop in the unusual environment of the red blood cells, the parasite causes structural remodelling of the host cell and biochemical changes through the export of virulence factors. Among the exportome are the molecular chaperones of the heat shock protein family, of which Hsp40s and Hsp70s are prominent. PF A0660w, a type II P. falciparum Hsp40, has been shown to be exported in complex with PfHsp70-x into the infected erythrocyte, suggesting possible functional interactions. However, the chaperone properties of PF A0660w and its interactions with proteins of parasite and human origin are yet to be investigated. Using a codon optimised coding region, PF A0660w was successfully expressed in E. coli M 15 [pREP4] cells. However, the expressed protein was largely deposited as insoluble pellet, and analysis of the pellets revealed a high percentage of PF A0660w, characteristic of inclusion body formation. PF A0660w was purified from inclusion bodies using additive enhanced solubilisation and refolding buffers followed by nickel affinity chromatography. SDS-PAGE and western analysis revealed that the purified protein was of high purity. Size exclusion chromatography showed that the protein existed as a monomer in solution and the secondary structure analysis using Fourier transformed infrared spectroscopy (FTIR) confirmed the success of the refolding approach. Its monomeric state suggests that PF A0660w may be functionally different from other Hsp40 that form dimers and that for PF A0660w, dimer formation may not be needed to maintain the stability of the protein in solution, but may occur in response to functional necessities during its interaction with partner Hsp70. PFA0660w was able to significantly stimulate the ATPase activity ofPfl-Isp70-x but not Pfl-Isp70-1 or human Hsp70 (HsHsp70), suggesting a specific functional interaction. Also, PF A0660w produced a dose dependent suppression of rhodanese aggregation and cooperated with Pfl-Isp70-1, PfHsp70-x and HsHsp70 to cause enhanced aggregation suppression. Its ability to independently suppress aggregation may help to maintain substrates in an unfolded conformation for eventual transfer to partner Hsp70s during refolding processes. Also, the in vivo characterisation using a PF A0660w peptide specific antibody confirmed that PF A0660w was exported into the cytosol of infected erythrocytes. Its lack of induction upon heat shock suggests that PF A0660w may not be involved in the response of the parasite to heat stress. Overall, this study has provided the first heterologous over-expression, purification and biochemical evidence for the possible functional role of PF A0660w, and has thereby provided the needed background for further exploration of this protein as a potential target for drug discovery.
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Bond, P. M. "Diversity in Plasmodium falciparum with particular reference to the infected erythrocyte". Thesis, University of Liverpool, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234840.
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Walker, Dawn Marie. "The Study of Autophagy in Plasmodium falciparum". The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1385586661.
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Hatherley, Rowan. "In silico characterisation of the four canonical plasmodium falciparum 70 kDa heat shock proteins". Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1004086.
Testo completoAbstract (sommario):
The 70 kDa heat shock proteins expressed by Plasmodium falciparum (PfHsp70s) are believed to be essential to both the survival and virulence of the malaria parasite. A total of six Hsp70 genes have been identified in the genome of P. falciparum. However, only four of these encode canonical Hsp70s, which are believed to localise predominantly in the cytosol (PfHsp70-1 and PfHsp70-x), the endoplasmic reticulum (PfHsp70-2) and mitochondria (PfHsp70-3) of the parasite. These proteins bind and release peptide substrates in an ATP-dependent manner, with the aid of a J-domain protein cochaperone and a nucleotide exchange factor (NEF). The aim of this study was to identify the residues involved in the interaction of these PfHsp70s with their peptide substrates, their J-domain cochaperones and potential NEFs. These residues were then mapped to three-dimensional (3D) structures of the proteins, modelled in three different conformations; each representing a different stage in the ATPase cycle. Additionally, these proteins were compared to different types of Hsp70s from a variety of different organisms and sequence features found to be specific to each PfHsp70 were mapped to their 3D structures. Finally, a novel modelling method was suggested, in which the structures of templates were remodelled to improve their quality before they were used in the homology modelling process. Based on the analysis of residues involved in interactions with other proteins, it was revealed that each PfHsp70 displayed features that were specific to its cellular localisation and each type of Hsp70 was predicted to interact with a different set of NEFs. The study of conserved features in each PfHsp70 revealed that PfHsp70-x displayed various sequence features atypical of both Plasmodium cytosolic Hsp70s and cytosolic Hsp70s in general. Additionally, residues conserved specifically in Hsp70s of Apicomplexa, Plasmodium and P. falciparum were identified and mapped to the each PfHsp70 model. Although these residues were too numerous to reveal any information of specific value, these models may be useful for the purposes of aiding the design of drug compounds against each PfHsp70. Finally, the novel modelling approach did show some promise. Half of the models produced using the modified templates were of a higher quality than their counterparts modelled using the original templates. This approach does still require a lot of validation work and statistical evaluation. It is hoped that it could prove to be a useful approach to homology modelling when the only templates available are poor quality structures.
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Beniamin, Armanos. "Establishment of an Expression and Purification System for Plasmodium falciparum Multi Drug Resistance (pfmdr) Transporter". Thesis, University of Skövde, School of Life Sciences, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-969.
Testo completoAbstract (sommario):
Malaria is a life threatening parasite disease caused and transmitted by infected female anopheles mosquito. However, the parasite, Plasmodium falciparum, has become resistant to most anti malarial drugs, such as chloroquine, which contributes to fever and anaemia because of its ability to digest the haemoglobin in the red blood cells. The aims of this project were to establish whether “Bac to Bac” Baculoviral Expression System is suitable for expression of pfmdr 1 gene and for purification of the pgh 1 protein. The pfmdr 1 gene encodes an ABC transporter protein, pgh 1, fixed in the cell membrane of the Plasmodium falciparuum gut, which assist in elimination of drug compounds. Furthermore, “Bac to Bac” Baculoviral Expression System uses vectors with histidine tags to clone the pfmdr 1 gene and subsequently transform these into DH10Bac cells to produce the recombinant bacmid DNA. Since pfmdr 1 gene is an AT-rich sequence, PCR was optimized, by lowering the annealing and extension temperature to 47Co and 66Co respectively. The results show that “Bac to Bac” Baculoviral Expression System can be used to express the pfmdr 1 gene, though further experiments has to be performed.
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Maphumulo, Philile Nompumelelo. "Characterisation of a plasmodium falciparum type II Hsp40 chaperone exported to the cytosol of infected erythrocytes". Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1015681.
Testo completoAbstract (sommario):
Heat Shock 40 kDa proteins (Hsp40s) partner with heat shock 70 kDa proteins (Hsp70s) in facilitating, among other chaperone activities; correct protein transport, productive protein folding and assembly within the cells; under both normal and stressful conditions. Hsp40 proteins regulate the ATPase activity of Hsp70 through interaction with the J-domain. Plasmodium falciparum Hsp70s (PfHsp70s) do not contain a Plasmodium export element (PEXEL) sequence although PfHsp70-1 and PfHsp70-3 have been located outside of the parasitophorous vacuole. Studies reveal that a type I P. falciparum (PfHsp40) chaperone (PF14_0359) stimulates the rate of ATP hydrolysis of the cytosolic PfHsp70 (PfHsp70-1) and that of human Hsp70A1A. PFE0055c is a PEXEL-bearing type II Hsp40 that is exported into the cytosol of P. falciparum-infected erythrocytes; where it potentially interacts with human Hsp70. Studies reveal that PFE0055c associates with structures found in the erythrocyte cytosol termed “J-dots” which are believed to be involved in trafficking parasite-encoded proteins through the erythrocyte cytosol. If P. falciparum exports PFE0055c into the host cytosol, it may be proposed that it interacts with human Hsp70, making it a possible drug target. The effect of PFE0055c on the ATPase activity of human Hsp70A1A has not been previously characterised. Central to this study was bioinformatic analysis and biochemical characterisation PFE0055c using an in vitro (ATPase assay) approach. Structural domains that classify PFE0055c as a type II Hsp40 were identified with similarity to two other exported type II PfHsp40s. Plasmids encoding the hexahistidine-tagged versions of PFE0055c and human Hsp70A1A were used for the expression and purification of these proteins from Escherichia coli. Purification was achieved using nickel affinity chromatography. The urea-denaturing method was used to obtain the purified PFE0055c whilst human Hsp70A1A was purified using the native method. PFE0055c could stimulate the ATPase activity of alfalfa Hsp70, although such was not the case for human Hsp70A1A in vitro.
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Coetzee, Linda. "Plasmodium falciparum dihydrofolate synthase (DHFS-FPGS) : gene synthesis and recombinant expression". Diss., 2004. http://hdl.handle.net/2263/24333.
Testo completoAbstract (sommario):
Malaria causes nearly 3 million deaths annually. The parasite species responsible for the most lethal forms of malaria is P. falciparum (Miller et.al., 2002). Its destructive effect is most evident in the developing African countries, which lack the infrastructure and financial support to effectively control the disease. The only viable means of control at this stage is the use of antimalarial chemotherapy and –prophylaxis, but these drugs are losing their effectivity due to parasite resistance. This underlines the need for new, safe, efficient and cheap drugs as a solution to the African malaria problem. Within the validated folate metabolic pathway of P. falciparum, the identification of three new genes has provided new options for drug inhibition (Lee et.al., 2001). One of these genes encodes the bifunctional dihydrofolate synthase-folylpolyglutamate synthase (DHFS-FPGS), which is unique to P. falciparum (Salcedo et.al., 2001). When compared to human folylpolyglutamate synthase (FPGS), the parasite enzyme is an attractive drug target for selective inhibition due to the additional DHFS activity and low sequence similarity. However, to assess the value of DHFS-FPGS as a drug target and rationally design new drugs against the enzyme, large amounts of enzyme are needed for activity studies and structural determination. The heterologous expression of malaria genes often result in low expression levels, due to its high A+T content and codon bias. To circumvent this problem, a modified P. falciparum dhfs-fpgs, adapted to E.coli codon preferences and with a lower A+T content was synthesised in this study for increased expression. A two-step overlap-extension PCR method was optimised for the synthesis of the 1586bp dhfs-fpgs from only 1 pmol each of partially overlapping oligonucleotides. The use of partially overlapping oligonucleotides, lower amounts of starting material and fewer PCR cycles cut the costs of gene synthesis and the optimisation increased PCR efficiency, when compared to other gene synthesis reports (Carpenter et al., 1999; Zhang et al., 2002). The correct sequences could be obtained from the sequencing of as little as three clones. The successfully constructed dhfs-fpgs gene was expressed in a variety of E. coli expression hosts and vector systems. In all the systems, expression levels of the synthetic gene were much higher than for the native P. falciparum gene. Functional complementation of a DHFS-FPGS deficient E. coli strain verified that the DHFS and FPGS activities were encoded by the synthetic gene, that complementation was achieved to a greater extent than for native P. falciparum dhfs-fpgs and that a synthetic tagless and C-terminal Histidine-tagged DHFS-FPGS had the highest levels of DHFS and FPGS activity. Preliminary purification studies for these two constructs were performed for optimised enzyme isolation, to be followed by activity assays. These optimisations will also serve as basis for future large-scale isolation strategies to obtain sufficient amounts of protein for the structural determination of the enzyme, which would be vital to drug target verification, drug development and –design, thus paving the way for a new generation of antifolate malaria therapy.Dissertation (MSc(Biochemistry))--University of Pretoria, 2006.
Biochemistry
unrestricted
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Manning, Suzanne Kathryn. "Molecular characterization of the hexose transporter (PfHT1) of Plasmodium falciparum in Xenopus laevis oocytes". Diss., 2001. http://hdl.handle.net/2263/29635.
Testo completo
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Smallie, Timothy Ian. "Cloning and recombinant expression of a 822 bp region of a Pf403 Plasmodium falciparum gene". Thesis, 2003. http://hdl.handle.net/10413/5641.
Testo completoAbstract (sommario):
Malaria is a devastating parasitic disease in humans caused by species in the genus Plasmodium.
With over 100 million cases and at least 1.5 million fatalities each year, the disease accounts for
4-5% of all fatalities in the world. A recent increase in the number of malaria cases in South
Africa has imposed severe costs on the economy and public health.
Immunity to malaria is a multi-component system involving both B and T celllymphocytes.
Pc96 is a 96 kDa antigen identified in the mouse malaria model Plasmodium chabaudi adami. It
is known to be associated with the outer membrane of mouse erythrocytes infected with the
parasite and has shown protective roles in mice challenged with P. chabaudi adami. A specific T
cell clone has been identified that adoptively provides protection to athymic mice infected with
P. chabaudi adami. Antibodies raised against Pc96 identified proteins that induced the
proliferation of the protective T cell clones. At least four other antigens of different species of.
malaria share at least one cross-reactive epitope.
In an attempt to identify a Plasmodiumfalciparum homologue ofPc96, the amino-acid sequence
was used in a BLAST search of the P. falciparum genome database, identifying a 403 kDa
protein with a high degree of homology to Pc96. Sequence alignments indicated a region
spanning 90 amino acids in Pf403 that overlaps the Pc96 amino acid sequence. A 178 kDa
protein in P. yoelii yoelii (Pyy178) was shown to be highly similar to Pc96. Tvcell epitope
prediction programs identified putative T cell epitopes in Pc96 which appear to be conserved in
Pf403 and Pyy178. A casein kinase IT phosphorylation site was also identified in this region and
is conserved in both sequences. PCR primers were designed to amplify regions of the
MAL3P6.11 gene coding for Pf403 from P.falciparum genomic DNA. An 817 bp region in the
MAL3P6.11 gene was amplified. This codes for the region ofPf403 that shows high homology
to Pc96 and contains the conserved T cell epitopes and casein kinase phophorylation site. A
BamHI site was incorporated into the forward primer to facilitate in-frame ligation with cloning
vectors. The PCRproduct obtained was verified by restriction analysis using HindIII and EcoRI
sites within the fragment.
The 817 bp peR product was cloned into the pMOSBlue vector using a blunt-endedPCR cloning
kit, and transformed into MOSBlue competent cells. Recombinants were identified using the uIV
complementation system, and verified by PCR, plasmid DNA isolation, and restriction digestion
analysis. The insertDNA in pMOSBlue was cut out with BamHI and sub-cloned into the BamHI
site in the pMAL-C2x expression vector. Sequencing ofthe construct confirmed the identity of
the cloned insert and showed the sequence to be in frame with the malE gene coding for maltose
binding protein (MBP). The fusion protein, MBP-Pf32 .5, was induced and expressed as a 75 kDa
protein comprising ofthe 32.5 kDa region ofPf403, and MBP (42.5 kDa) and was detected by
anti-MBP antibodies, by western blotting. This recombinant protein has many applications for
further studies involving the characterisation of the Pf403 protein, and the determination of
possible roles that the protein may have in stimulating an immune response during human
malaria infections.Thesis (M.Sc.) - University of Natal, Pietermaritzburg, 2003.
Libri sul tema "Plasmodium falciparum – Research"
1
Malaria and the red cell 2: Proceedings of the Second Workshop on Malaria and the Red Cell, held in Ann Arbor, Michigan, October 24, 1988 (Progress in clinical and biological research). A.R. Liss, 1989.
Cerca il testo completo
2
Franceschi, Silvia, Hashem B. El-Serag, David Forman, Robert Newton e Martyn Plummer. Infectious Agents. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190238667.003.0024.
Testo completoAbstract (sommario):
Eleven infectious agents (seven viruses, three parasites, and one bacterium) have been classified by the International Agency for Research on Cancer as carcinogenic to humans for one or more cancer sites: hepatitis B virus; hepatitis C virus; thirteen types of human papillomavirus (HPV); human immunodeficiency virus type 1 (HIV-1); human T-cell leukemia virus type 1; Epstein-Barr virus; Kaposi sarcoma herpesvirus; Helicobacter pylori; Opisthorchis viverrini; Clonorchis sinensis; and Schistosoma haematobium. Other infectious agents, such as Merkel cell polyomavirus, Plasmodium falciparum, and cutaneous HPVs, have been classified as “probably carcinogenic” or “possibly carcinogenic.” Accurate biomarkers of chronic infection have been essential for estimating risk and ascribing a causal role to infectious agents in cancer. Of the 14 million cases of cancer estimated to have occurred worldwide in 2012, 2.2 million were caused by infectious agents. Vaccination and screen-and-treat programs have the potential for greatly reducing the burden of cancer caused by infections.
Capitoli di libri sul tema "Plasmodium falciparum – Research"
1
Bachrach, U., L. Abu-Elheiga, Y. G. Assaraf, J. Golenser e D. T. Spira. "Polyamines in the Cell Cycle of the Malarial Parasite Plasmodium Falciparum". In Progress in Polyamine Research, 643–50. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4684-5637-0_57.
Testo completo
2
Strowig, Till, e Alexander Ploss. "Plasmodium Falciparum Parasite Development in Humanized Mice: Liver And Blood Stages". In Humanized Mice for HIV Research, 519–28. New York, NY: Springer New York, 2014. http://dx.doi.org/10.1007/978-1-4939-1655-9_41.
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Maréchal, E., N. Azzouz, C. Mercier, C. Santos de Macedo, M. A. Block, J. F. Dubremetz, J. E. Feagin, M. F. Cesbron-Delauw, R. T. Schwarz e J. Joyard. "Synthesis of Chloroplast Galactolipids in Apicomplexan Parasites (Toxoplasma Gondii and Plasmodium Falciparum)". In Advanced Research on Plant Lipids, 167–70. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-017-0159-4_38.
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CHEN, GUOXIAN. "POINT MUTATIONS IN THE DIHYDROFOLATE REDUCTASE-THYMIDYLATE SYNTHASE GENE AS THE MOLECULAR BASIS OF PYRIMETHAMINE RESISTANCE IN PLASMODIUM FALCIPARUM". In Retrospect and Prospect of Protein Research, 153–58. WORLD SCIENTIFIC, 1991. http://dx.doi.org/10.1142/9789814360425_0029.
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