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Sent on Saturday, 2009 Oct 31Search kinetoplastids OR kinetoplastid OR Kinetoplastida OR "trypanosoma brucei" OR leishmania OR brucei OR leishmaniasis OR "African trypanosomiasis"
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| PubMed Results |
| 1. | Eur J Immunol. 2009 Oct 28. [Epub ahead of print]Leishmania donovani-induced expression of SIRPalpha on kupffer cells enhances hepatic invariant NKT cell activation.Beattie L, Svensson M, Bune A, Brown N, Maroof A, Zubairi S, Smith KR, Kaye PM.Centre for Immunology and Infection, Hull York Medical School and Department of Biology, University of York, York, YO10 5YW, UK. SIRPalpha and its cognate ligand CD47 have been documented to have a broad range of cellular functions in development and immunity. Here we investigated the role of SIRPá- CD47 signalling in iNKT cell responses. We found that CD47 was required for the optimal production of IFN-gammafrom splenic invariant iNKT cells following exposure to áGalCer analogue PBS-57 and in vivo infection of mice with Leishmania donovani. Surprisingly, although SIRPá was undetectable in the liver of uninfected mice, the hepatic invariant iNKT cell response to infection was also impaired in CD47(-/-) mice. However, we found that SIRPá was rapidly induced on Kupffer cells following L. donovani infection, via a mechanism involving G-protein coupled receptors. Thus, we describe a novel amplification pathway affecting cytokine production by hepatic iNKT cells, which may facilitate the breakdown of hepatic tolerance after infection. |
| PMID: 19877019 [PubMed - as supplied by publisher] | |
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| 2. | Mem Inst Oswaldo Cruz. 2009 Sep;104(6):918-22.Histopathology of Leishmania major infection: revisiting L. major histopathology in the ear dermis infection model.Cangussú SD, Souza CC, Campos CF, Vieira LQ, Afonso LC, Arantes RM.Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil, 31270-901. We describe the relationship between lesion outcome and histopathological hallmarks in susceptible (BALB/c) and resistant (C57BL/6 and IL-4-deficient BALB/c) mouse strains over the course of a 12-week-infection with Leishmania major in the ear. The infiltration of mononuclear cells and polymorphonuclear cells occurred within 6 h and mononuclear cells predominated one week post-infection. Permissive intracellular growth of the pathogen was associated with non-healing lesions. In contrast, tissue damage and clearance of the parasite was observed in healing lesions and was associated with inducible nitric oxide synthase expression. The identification of the structural components of tissue reaction to the parasite in this study furthers our understanding of subjacent immune effector mechanisms. |
| PMID: 19876567 [PubMed - in process] | |
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| 3. | Mem Inst Oswaldo Cruz. 2009 Sep;104(6):914-7.Serological diagnosis of Chagas disease: evaluation and characterisation of a low cost antigen with high sensitivity and specificity.Campos Y, Briceño L, Reina K, Figarella K, Pérez JL, Mosca W.Laboratorio de Fisiopatología (Nodo I LANPIP), Instituto de Biomedicina, Facultad de Medicina, Universidad Central de Venezuela, Caracas, Venezuela. In spite of evident progress in the serology of Chagas disease, the requirement for new diagnostic antigens persists. We have evaluated different antigens obtained from Trypanosoma cruzi grown in medium rich in nutrients or under nutrient stress, autoclaved or sonicated and fractionated by differential centrifugation. The resulting antigens were evaluated for diagnosis of Chagas disease using ELISA. Immunofluorescence of the parasites demonstrated that nutrient stress induced changes in the distribution and density of antigens recognised by a pool of sera from experimentally infected mice. When evaluated using ELISA, it was evident that most fractions had good sensitivity but poor specificity. Surprisingly, the best specificity and sensitivity was observed with parasites cultured under nutrient stress and autoclaved. Furthermore this antigen had low cross reactivity with sera from other parasitic diseases, Leishmaniasis in particular. Western blot analysis demonstrated that autoclaving seems to non-specifically eliminate cross-reactive antigens. In conclusion, autoclaving epimastigotes of T. cruzi, after nutrient stress, allowed us to obtain an antigen that could be used in the serological diagnosis of Chagas disease. |
| PMID: 19876566 [PubMed - in process] | |
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| 4. | J Biol Chem. 2009 Oct 29. [Epub ahead of print]Thiolated tRNAs of Trypanosoma brucei are imported into mitochondria and dethiolated after import.Bruske EI, Sendfeld F, Schneider A.University of Bern, Switzerland. All mitochondrial tRNAs in Trypanosoma brucei derive from cytosolic tRNAs that are in part imported into mitochondria. Some trypanosomal tRNAs are thiolated in a compartment-specific manner. We have identified three proteins required for the thio modification of cytosolic tRNA(Gln), tRNA(Glu) and tRNA(Lys). RNAi-mediated ablation of these proteins results in the cytosolic accumulation non thio-modified tRNAs but does not increase their import. Moreover, in vitro import experiments showed that both thio-modified and non thio-modified tRNA(Glu) can efficiently be imported into mitochondria. These results indicate that unlike previously suggested the cytosol-specific thio modifications do not function as antideterminants for mitochondrial tRNA import. Consistent with these results we showed by using inducible expression of a tagged tRNA(Glu) that it is mainly the thiolated form which is imported in vivo. Unexpectedly, the imported tRNA becomes dethiolated after import which explains why the non thiolated form is enriched in mitochondria. Finally, we have identified two genes required for thiolation of imported tRNA(Trp) whose wobble nucleotide is subject to mitochondrial C to U editing. Interestingly, downregulation of thiolation resulted in an increase of edited tRNA(Trp) but did not affect growth. |
| PMID: 19875444 [PubMed - as supplied by publisher] | |
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| 5. | Trop Med Int Health. 2009 Oct 26. [Epub ahead of print]In vitro sensitivity of Leishmania (Viannia) braziliensis and Leishmania (Leishmania) amazonensis Brazilian isolates to meglumine antimoniate and a mphotericin B.Zauli-Nascimento RC, Miguel DC, Yokoyama-Yasunaka JK, Pereira LI, Pelli de Oliveira MA, Ribeiro-Dias F, Dorta ML, Uliana SR.Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil. Summary Resistance of Leishmania parasites to specific chemotherapy has become a well-documented problem in the Indian subcontinent in recent years but only a few studies have focused on the susceptibility of American Leishmania isolates. Our susceptibility assays to meglumine antimoniate were performed against intracellular amastigotes after standardizing an in vitro model of macrophage infection appropriate for Leishmania (Viannia) braziliensis isolates. For the determination of promastigote susceptibility to amphotericin B, we developed a simplified MTT-test. The sensitivity in vitro to meglumine antimoniate and amphotericin B of 13 isolates obtained from Brazilian patients was determined. L. (V.) braziliensis isolates were more susceptible to meglumine antimoniate than Leishmania (Leishmania) amazonensis. EC(50), EC(90) and activity indexes (calculated over the sensitivity of reference strains), suggested that all isolates tested were susceptible in vitro to meglumine antimoniate, and did not show association with the clinical outcomes. Isolates were also uniformly susceptible in vitro to amphotericin B. |
| PMID: 19874570 [PubMed - as supplied by publisher] | |
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| 6. | J Bioenerg Biomembr. 2009 Jun;41(3):299-308. Epub 2009 Jul 18.Mitochondrial bioenergetics and redox state are unaltered in Trypanosoma cruzi isolates with compromised mitochon drial complex I subunit genes.Carranza JC, Kowaltowski AJ, Mendonça MA, de Oliveira TC, Gadelha FR, Zingales B.Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brasil. In trypanosomatids the involvement of mitochondrial complex I in NADH oxidation has long been debated. Here, we took advantage of natural Trypanosoma cruzi mutants which present conspicuous deletions in ND4, ND5 and ND7 genes coding for complex I subunits to further investigate its functionality. Mitochondrial bioenergetics of wild type and complex I mutants showed no significant differences in oxygen consumption or respiratory control ratios in the presence of NADH-linked substrates or FADH(2)-generating succinate. No correlation could be established between mitochondrial membrane potentials and ND deletions. Since release of reactive oxygen species occurs at complex I, we measured mitochondrial H(2)O(2) formation induced by different substrates. Significant differences not associated to ND deletions were observed among the parasite isolates, demonstrating that these mutations are not important for the control of oxidant production. Our data support the notion that complex I has a limited function in T. cruzi. |
| PMID: 19618257 [PubMed - indexed for MEDLINE] | |
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