What's new for 'Trypanosomatids' in PubMed

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Sent on Wednesday, 2011 Mar 30
Search kinetoplastids OR kinetoplastid OR Kinetoplastida OR "trypanosoma brucei" OR leishmania OR brucei OR leishmaniasis OR "African trypanosomiasis"
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PubMed Results

Items 1 - 7 of 7

1.	Appl Biochem Biotechnol. 2011 Mar 29. [Epub ahead of print] Biophysical and Folding Parameters of Trypanothione Reductase from Leishmania infantum. Shukla AK, Patra S, Dubey VK. Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India. Abstract Out of various tropical diseases caused by trypanosomatids, leishmaniasis is a life-threatening disease caused by the leishmania parasite. We are targeting the thiol metabolic pathway of the parasite for drug development, and trypanothione reductase (TryR) is a key enzyme of this pathway. It is important to gather significant knowledge about biophysical and intrinsic properties of this enzyme which will be helpful in better understanding of this drug-target enzyme. We report here the modulation of activity and stability of TryR from Leishmania infantum in the presence of various denaturants and pHs. The enzyme is quite stable under high concentration of denaturants and showed better stability compared to TryR of Leishmania donovani, whose sequence differs at only on position (Ala363→Gly). Structural basis of the destabilizing effects is discussed.
	PMID: 21445596 [PubMed - as supplied by publisher]
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2.	PLoS One. 2011 Mar 21;6(3):e14773. Ecology of phlebotomine sand flies in the rural community of mont rolland (thiès region, senegal): area of transmission of canine leishmaniasis. Senghor MW, Faye MN, Faye B, Diarra K, Elguero E, Gaye O, Bañuls AL, Niang AA. Laboratoire de Zoologie des Invertébrés Terrestres, Institut Fondamental d'Afrique Noire Cheikh Anta Diop, Université Cheikh Anta Diop, Dakar, Sénégal. Abstract BACKGROUND: Different epidemiological studies previously indicated that canine leishmaniasis is present in the region of Thiès (Senegal). However, the risks to human health, the transmission cycle and particularly the implicated vectors are unknown. METHODOLOGY/PRINCIPAL FINDINGS: To improve our knowledge on the population of phlebotomine sand flies and the potential vectors of canine leishmaniasis, sand flies were collected using sticky traps, light traps and indoor spraying method using pyrethroid insecticides in 16 villages of the rural community of Mont Rolland (Thiès region) between March and July 2005. The 3788 phlebotomine sand flies we collected (2044 males, 1744 females) were distributed among 9 species of which 2 belonged to the genus Phlebotomus: P. duboscqi (vector of cutaneous leishmaniasis in Senegal) and P. rodhaini. The other species belonged to the genus Sergentomyia: S. adleri, S. clydei, S. antennata, S. buxtoni, S. dubia, S. schwetzi and S. magna. The number of individuals and the species composition differed according to the type of trap, suggesting variable, species-related degrees of endophily or exophily. The two species of the genus Phlebotomus were markedly under-represented in comparison to the species of the genus Sergentomyia. This study also shows a heterogeneous spatial distribution within the rural community that could be explained by the different ecosystems and particularly the soil characteristics of this community. Finally, the presence of the S. dubia species appeared to be significantly associated with canine leishmaniasis seroprevalence in dogs. CONCLUSIONS/SIGNIFICANCE: Our data allow us to hypothesize that the species of the genus Sergentomyia and particularly the species S. dubia and S. schwetzi might be capable of transmitting canine leishmaniasis. These results challenge the dogma that leishmaniasis is exclusively transmitted by species of the genus Phlebotomus in the Old World. This hypothesis should be more thoroughly evaluated.
	PMID: 21445295 [PubMed - in process]
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3.	Blood. 2011 Mar 28. [Epub ahead of print] H-ras and N-ras are dispensable for T-cell development and activation but critical for protective Th1 immunity. Iborra S, Soto M, Stark-Aroeira L, Castellano E, Alarcón B, Alonso C, Santos E, Fernández-Malavé E. Centro de Biologia Molecular Severo Ochoa, Consejo Superior de Investigaciones Cientificas, Departamento de Biologia Molecular, Universidad Autonoma de Madrid, Madrid, Spain; Abstract The small guanine-nucleotide-binding proteins of the Ras family, including in mammals the highly homologous H-ras, N-ras, and K-ras isoforms, are rapidly activated upon ligation of the T-cell antigen receptor (TCR), but whether each isoform plays specific roles in T cells is largely unknown. Here we show, by using mice specifically lacking H-ras or N-ras, that these isoforms are dispensable for thymocyte development and mature T-cell activation. By contrast, CD4(+) T cells from Ras-deficient mice exhibited markedly decreased production of the T helper type 1 (Th1) signature cytokine interferon (IFN)-γ early after TCR stimulation, concomitantly with impaired induction of the Th1-specific transcription factor T-bet. Accordingly, Ras-deficient mice failed to mount a protective Th1 response in vivo against the intracellular parasite Leishmania major, although they could be rendered resistant to infection if a Th1-biased milieu was provided during parasite challenge. Collectively, our data indicate that the TCR recruits distinct Ras isoforms for signal transduction in developing and mature T cells, thus providing a mechanism for differential signaling from the same surface receptor. Furthermore, we demonstrate for the first time that H-ras and N-ras act as critical controllers of Th1 responses mostly by transmitting TCR signals for Th1 priming of CD4(+) T cells.
	PMID: 21444916 [PubMed - as supplied by publisher]
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4.	Plant Physiol. 2011 Mar 28. [Epub ahead of print] UDP-sugar pyrophosphorylase - a new old mechanism for sugar activation. Kleczkowski LA, Decker D, Wilczynska M. Umea University. Abstract Recent developments in studies on properties and functions of UDP-sugar pyrophosphorylase (USPase) in metabolism are presented. The protein was characterized from plants and protozoans (Leishmania, Trypanosoma), but apparently it is also present in bacteria. In plants, USPase deficiency leads to male-sterility. USPase produces a variety of UDP-sugars and their analogs required for cell wall biosynthesis as well as for protein and lipid glycosylation, among other functions. Substrate specificity of USPases from different sources is reviewed, and their function/ structure properties are discussed, based on recent crystallization of the protein, with emphasis on common structural blueprint with some other pyrophosphorylases. Some strategies for future research on USPase are discussed.
	PMID: 21444645 [PubMed - as supplied by publisher]
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5.	J Proteomics. 2011 Mar 25. [Epub ahead of print] Adaptation of a 2D in-gel kinase assay to trace phosphotransferase activities in the human pathogen Leishmania donovani. Schmidt-Arras D, Leclercq O, Gherardini PF, Helmer-Citterich M, Faigle W, Loew D, Späth GF. Department of Parasitology and Mycology, G5 Virulence Parasitaire, Institut Pasteur, Paris, France; CNRS URA2581, Institut Pasteur, Paris, France. Abstract The protozoan parasite Leishmania donovani undergoes various developmental transitions during its infectious cycle that are triggered by environmental signals encountered inside insect and vertebrate hosts. Intracellular differentiation of the pathogenic amastigote stage is induced by pH and temperature shifts that affect protein kinase activities and downstream protein phosphorylation. Identification of parasite proteins with phosphotransferase activity during intracellular infection may reveal new targets for pharmacological intervention. Here we describe an improved protocol to trace this activity in L. donovani extracts at high resolution combining in-gel kinase assay and two-dimensional gel electrophoresis. This 2D procedure allowed us to identify proteins that are associated with amastigote ATP-binding, ATPase, and phosphotransferase activities. The 2D in-gel kinase assay, in combination with recombinant phospho-protein substrates previously identified by phospho-proteomics analyses, provides a novel tool to establish specific protein kinase-substrate relationships thus improving our understanding of Leishmania signal transduction with relevance for future drug development. Copyright © 2010. Published by Elsevier B.V.
	PMID: 21443974 [PubMed - as supplied by publisher]
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6.	Methods Mol Biol. 2011;689:69-80. Histological approaches to study tissue parasitism durin g the experimental Trypanosoma cruzi infection. Fabrino DL, Ribeiro GA, Teixeira L, Melo RC. Laboratory of Cellular Biology, Department of Biology, ICB, Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil. danifabrino@ufjf.edu.br Abstract During acute infection with the parasite Trypanosoma cruzi, the causal agent of Chagas' disease, tissue damage is related to intense tissue parasitism. Here we discuss histological approaches for an optimal visualization and quantification of T. cruzi nests in the heart, the main target organ of the parasite. These analyses are important to evaluate the course of the infection in different experimental models and also can be used to investigate parasite colonization and inflammatory processes in other infected tissues and biopsies.
	PMID: 21153787 [PubMed - indexed for MEDLINE]
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7.	Exp Parasitol. 2011 Mar;127(3):672-9. Epub 2010 Nov 29. Effect of repetitiveness on the immunogenicity and antigenicity of Trypanosoma cruzi F RA protein. Valiente-Gabioud AA, Veaute C, Perrig M, Galan-Romano FS, Sferco SJ, Marcipar IS. Laboratorio de Tecnología Inmunológica, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina. Abstract Repetitive proteins (RP) of Trypanosoma cruzi are highly present in the parasite and are strongly recognized by sera from Chagas' disease patients. Flagelar Repetitive Antigen (FRA), which is expressed in all steps of the parasite life cycle, is the RP that displays the greatest number of aminoacids per repeat and has been indicated as one of the most suitable candidate for diagnostic test because of its high performance in immunoassays. Here we analyzed the influence of the number of repeats on the immunogenic and antigenic properties of the antigen. Recombinant proteins containing one, two, and four tandem repeats of FRA (FRA1, FRA2, and FRA4, respectively) were obtained and the immune response induced by an equal amount of repeats was evaluated in a mouse model. The reactivity of specific antibodies present in sera from patients naturally infected with T. cruzi was also assessed against FRA1, FRA2, and FRA4 proteins, and the relative avidity was analyzed. We determined that the number of repeats did not increase the humoral response against the antigen and this result was reproduced when the repeated motifs were alone or fused to a non-repetitive protein. By contrast, the binding affinity of specific human antibodies increases with the number of repeated motifs in FRA antigen. We then concluded that the high ability of FRA to be recognized by specific antibodies from infected individuals is mainly due to a favorable polyvalent interaction between the antigen and the antibodies. In accordance with experimental results, a 3D model was proposed and B epitope in FRA1, FRA2, and FRA4 were predicted. Copyright © 2010 Elsevier Inc. All rights reserved.
	PMID: 21118687 [PubMed - indexed for MEDLINE]
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