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Sent on Tuesday, 2010 Apr 27Search kinetoplastids OR kinetoplastid OR Kinetoplastida OR "trypanosoma brucei" OR leishmania OR brucei OR leishmaniasis OR "African trypanosomiasis"
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| PubMed Results |
| 1. | Methods Mol Biol. 2010;637:245-62.Glucose transporters in parasitic protozoa.Landfear SM.Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, USA. AbstractGlucose and related hexoses play central roles in the biochemistry and metabolism of single-cell parasites such as Leishmania, Trypanosoma, and Plasmodium that are the causative agents of leishmaniasis, African sleeping sickness, and malaria. Glucose transporters and the genes that encode them have been identified in each of these parasites and their functional properties have been scrutinized. These transporters are related in sequence and structure to mammalian facilitative glucose transporters of the SLC2 family, but they are nonetheless quite divergent in sequence. Hexose transporters have been shown to be essential for the viability of the infectious stage of each of these parasites and thus may represent targets for development of novel anti-parasitic drugs. The study of these transporters also illuminates many aspects of the basic biology of Leishmania, trypanosomes, and malaria parasites. |
| PMID: 20419439 [PubMed - in process] | |
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| 2. | Eukaryot Cell. 2010 Apr 23. [Epub ahead of print]TbPRMT6 is a Type I protein arginine methyltransferase that contributes to cytokinesis in Trypanosoma brucei.Fisk JC , Zurita-Lopez C, Sayegh J, Tomasello DL, Clarke SG, Read LK.Department of Microbiology and Immunology, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14124; Department of Chemistry and Biochemistry and the Molecular Biology Institute. University of California at Los Angeles, Los Angeles, CA 90095. AbstractArginine methylation is a widespread posttranslational modification of proteins catalyzed by a family of protein arginine methyltransferases (PRMTs). In yeast and mammals, this modification impacts multiple cellular processes such as chromatin remodeling leading to transcriptional regulation, RNA processing, DNA repair, and cell signaling. The protozoan parasite, Trypanosoma brucei, possesses five putative PRMTs in its genome. This is a large number of PRMTs relative to other unicellular eukaryotes, suggesting an important role for arginine methylation in trypanosomes. Here, we present the in vitro and in vivo characterization of a T. brucei enzyme homologous to human PRMT6, which we term TbPRMT6. Like human PRMT6, TbPRMT6 is a Type I PRMT, catalyzing the production of monomethylarginine and asymmetric dimethylarginine residues. In in vitro methylation assays, TbPRMT6 utilizes bovine histones as a substrate, but it does not methylate several T. brucei glycine/arginine rich proteins. As such, it exhibits a relatively narrow substrate specificity compared to other T. brucei PRMTs. Knockdown of TbPRMT6 in both procyclic form and bloodstream form T. brucei leads to a modest but reproducible effect on parasite growth in culture. Moreover, upon TbPRMT6 depletion, both PF and BF exhibit aberrant morphologies indicating defects in cell division, and these defects differ in the two life cycle stages. Mass spectrometry of TbPRMT6 associated proteins reveals histones, components of the nuclear pore complex, and flagellar proteins that may represent TbPRMT6 substrates contributing to the observed growth and morphological defects. |
| PMID: 20418380 [PubMed - as supplied by publisher] | |
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| 3. | Eukaryot Cell. 2010 Apr 23. [Epub ahead of print]Calflagin Inhibition Prolongs Host Survival and Suppresses Parasitemia in Trypanosoma brucei Infection.Emmer BT, Daniels MD, Taylor JM, Epting CL, Engman DM.Departments of Pathology and Microbiology-Immunology, and Department of Pediatrics, Northwestern University, Chicago, Illinois. AbstractAfrican trypanosomes express a family of dually acylated, EF-hand calcium-binding proteins called the calflagins. These proteins associate with lipid raft microdomains in the flagellar membrane where they putatively function as calcium signaling proteins. To date, however, their functions have remained unclear. Here, we show that these proteins bind calcium with high affinity and that their expression is regulated during the life cycle stage of the parasite, with protein levels approximately 10-fold higher in the mammalian bloodstream form than in the insect vector procyclic stage. We also demonstrate a role for the calflagins in mammalian infection, as inhibition of the entire calflagin family by RNA interference dramatically increasing host survival and attenuating parasitemia in a mouse model of sleeping sickness. In contrast to infection with parental wild-type parasites, which demonstrated an unremitting parasitemia and death within 6-10 days, infection with calflagin-depleted parasites demonstrated prolonged survival, associated with a sudden decrease in parasitemia at approximately 8 days post-infection. Subsequent relapsing and remitting waves of parasitemia thereafter were associated with alternate expression of the variant surface glycoprotein, suggesting that initial clearance was antigen-specific. Interestingly, despite the notable in vivo phenotype and flagellar localization of the calflagins, in vitro analysis of the calflagin-deficient parasites demonstrated normal proliferation, flagellar motility, and morphology. Further analysis of the kinetics of surface antibody clearance also did not demonstrate a deficit in the calflagin-deficient parasites; thus, the molecular basis for the altered course of infection is independent of an effect on parasite cell cycle progression, motility, or degradation of surface-bound antibodies. |
| PMID: 20418379 [PubMed - as supplied by publisher] | |
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| 4. | Vet J. 2010 Apr 23. [Epub ahead of print]High levels of serum matrix metalloproteinases in dogs with natural visceral leishmaniosis: A preliminary report.Melo GD, Marangoni NR, Marcondes M, Lima VM, Machado GF.Universidade Estadual Paulista "Júlio de Mesquita Filho"(UNESP), School of Veterinary Medicine, Araçatuba, SP, Brazil. AbstractThe hallmark microscopic lesion in canine visceral leishmaniosis is the accumulation of lymphocytes and macrophages parasitized by amastigotes of Leishmania in the lymphoid organs. Matrix metalloproteinase (MMP)-2 and MMP-9 are important for leukocyte migration as they degrade the type IV collagen in the basal lamina. Sera from 65 dogs, 53 with serological diagnosis of visceral leishmaniosis and 12 healthy ones, were analysed by gelatin-zymography to detect MMP-2 and MMP-9 activity. The infected dogs presented higher levels of serum mature MMP-9, proMMP-9 and proMMP-2 than control dogs. No mature MMP-2 activity was observed. The levels of mature and proMMP-9 were highly correlated. These findings suggest that the multi-systemic inflammatory lesions observed in visceral leishmaniosis are associated with an increase in serum MMPs, especially MMP-9. In concert with other clinical data, quantification of serum MMP-9 in infected dogs may lead to a better understanding of the pathogenesis of visceral leishmaniosis. Copyright © 2010 Elsevier Ltd. All rights reserved. |
| PMID: 20418130 [PubMed - as supplied by publisher] | |
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| 5. | Exp Parasitol. 2010 Apr 21. [Epub ahead of print]Leishmania major: Disruption of si gnal peptidase type I and its consequences on survival, growth and infectivity.Taheri T, Salmanian AH, Gholami E, Doustdari F, Zahedifard F, Rafati S.Molecular Immunology and Vaccine Research Lab, Pasteur Institute of Iran, Tehran, Iran; National Institute of Genetic Engineering and Biotechnology, Tehran, Iran. AbstractLeishmania major (L. major) signal peptidase type I (SPase I) is an endopeptidase encoded by a single-copy gene. In all organisms, SPase I is responsible for removing the signal peptide from secretory pre-proteins and releasing mature proteins to cellular or extra-cellular space. In this study, the role of SPase I in L. major is investigated by gene deletion using homologous recombination (HR). The null mutant of SPase I was not possible to create, suggesting that SPase I is an essential gene for parasite survival. The obtained heterozygote mutant by disrupting one allele of SPase I in L. major showed significantly reduced level of infectivity in bone marrow-derived macrophages. In addition, the heterozygote mutants are unable to cause cutaneous lesion in susceptible BALB/c mice. This is the first report showing that SPase I may have an important role in Leishmania infectivity, e.g. in differentiation and survival of amastigotes. Apparently, the SPase I expression is not essential for in vitro growth of the parasite. Copyright © 2010. Published by Elsevier Inc. |
| PMID: 20417202 [PubMed - as supplied by publisher] | |
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| 6. | Zhongguo Shi Yan Xue Ye Xue Za Zhi. 2010 Apr;18(2):463-5.[Clinical analysis on 28 patients with hemophagocytic lymphohistocytosis syndrome.][Article in Chinese] Shu MM, Zhu HF, Zhang T, Gao GX, Chen XQ.Department of Hematology, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, Shaani Province, China. AbstractIn order to profoundly understand the clinical and laboratorial characteristics and inducing factors of hemophagocytic lymphohistocytosis syndrome (HLH), 28 HLH patients received from 2004 to 2009 years in our hispital were analyzed retrospectively. The results indicated that all of the patients had a history with prolonged fever (more than 1 week), pancytopenia, hepatosplenomegaly, elevated ferritin level, hypofibrinogen, and hemophagocytosis in bone marrow. HLH was the first characteristic sign of malignant lymphoma in 9 patients; 1 patient had a clinical manifestation similar to fulminant hepatic failure; severe psycho-abnormity occurred in 1 HLH patient and pronounced hemophagocytosis were detected in his cerebrospinal fluid; 1 patient was eventually diagnosed as having HLH by the findings in a lymph node biopsy showing obvious hemophagocytosis. Additionally, the analysis of underlying factors in 28 patients with HLH indicated 11 patients with EB virus-associated HLH, 11 with lymphoma-associated HLH, 2 with Leishmania-associated HLH, and 3 with autoimmune disease-associated HLH. It is concluded that HLH disease is characterised with high heterogenicity in both clinical features and inducing factors; in addition, the patients from a pasturing area should be paid attention to parasite infection such as leishmania. |
| PMID: 20416189 [PubMed - in process] | |
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| 7. | Tunis Med. 2010 Jan;88(1):9-11.[Side effects of meglumine antimoniate in cutaneous leishmaniasis: 15 cases][Article in French] Ezzine Sebai N, Mrabet N, Khaled A, Zeglaoui F, Kharfi M, Fazaa B, Kamoun MR.Service de Dermatologie, Hôpital Charles Nicolle, Boulevard 9 Avril, Tunis, Tunisie. AbstractBACKGROUND: Leishmaniasis is wide spread parasitic disease considered to be endemic in 88 countries in both old and new world. The standard treatment remains Meglumine antimoniate. AIM: We study the side effects of systemic meglumine antimoniate in cutaneous leishmaniasis. METHODS: We conduct a retrospective study covering 3-year period (2002- 2005). All medical reports of cutaneous leishmaniasis treated by systemic Meglumine antimoniate are reviewed. RESULTS: The study comprise 63 patients all treated by systemic meglumine antimoniate at the dose of 60 mg/kg/day for 10-15 days. Side effects were noted in 15 cases (12 females and 3 males). The subject's age range from 11 to 78 years. Stibio-intolerance (fever, rash, arthralgia, abdominal pain) was observed in 12 cases and stibiotoxicity in 3 cases: precordialgies 1 case, hyperamylasemia and increase liver enzyme: 1 case, pancytopenia, renal and hepatic failure leading to death: 1 case, skin eruption: 7 cases, pruritis and erythema in the site of injection: 5 cases, urticaria: 1 case. Meglumine antimoniate was stopped in 13 cases. CONCLUSION: Meglumine antimoniate is the generally recommended treatment of cutaneous leishmaniasis. In spite of the rarity of Glucantime's side effects, we recommend a careful survey especially in older patients. |
| PMID: 20415206 [PubMed - in process] | |
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| 8. | FEMS Immunol Med Microbiol. 2010 Feb;58(1):51-60. Epub 2009 Sep 21.Complementary medicinal chemistry-driven strategies toward new antitrypanosomal and antil eishmanial lead drug candidates.Cavalli A, Lizzi F, Bongarzone S, Belluti F, Piazzi L, Bolognesi ML.Department of Pharmaceutical Sciences, Alma Mater Studiorum, University of Bologna, Bologna, Italy. AbstractTrypanosomiases and Leishmaniases are neglected tropical diseases that affect the less developed countries. For this reason, they did not and still do not have high visibility in Western societies. The name neglected diseases also refers to the fact that they often received little interest at the level of public investment, research and development. The drug discovery scenario, however, is changing dramatically. After a period in which different socioeconomic factors have prevented massive research efforts in this field, such efforts have increased considerably in the very recent years, with significant scientific advancements. In this context, we have embarked on a new drug discovery project devoted to identification of new small molecules for the treatment of trypanosomal and leishmanial diseases. Two complementary approaches have been pursued and are reported here. The first deals with a structure-based drug design, and a privileged structure-guided synthesis of quinazoline compounds able to modulate trypanothione reductase activity was accomplished. In the second, a combinatorial library, built on a natural product-based strategy, was synthesized. Using whole parasite assays, different quinones have been identified as promising lead compounds. A combination of both approaches to hopefully overcome some of the challenges of anti-trypanosomatid drug discovery has eventually been proposed. |
| PMID: 19845762 [PubMed - indexed for MEDLINE] | |
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