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Sent on Wednesday, 2010 Dec 22Search kinetoplastids OR kinetoplastid OR Kinetoplastida OR "trypanosoma brucei" OR leishmania OR brucei OR leishmaniasis OR "African trypanosomiasis"
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| PubMed Results |
| 1. | Infect Immun. 2010 Dec 20. [Epub ahead of print]Enhancement of Experimental Cutaneous Leishmaniasis by Leishmania Molecules. I. Dependency on IL-4, Serine-Protease/Esterase Activity, and Parasite and Host Genetic Backgrounds.Silva VM, Larangeira DF, Oliveira PR, Sampaio RB, Suzart P; Biointervention Student Group, Nihei JS, Teixeira MC, Mengel JO, Dos-Santos WL, Pontes-de-Carvalho L.Centro de Pesquisa Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Brazil; Faculdade de Farmácia, Universidade Federal da Bahia, Salvador, Brazil; Escola Bahiana de Medicina e Saúde Pública, Salvador, Brazil. AbstractMost inbred strains of mice, like the BALB/c, are susceptible to Leishmania amazonensis and resistant to Leishmania braziliensis infections. This parasite-related difference could result from the activity of a L. amazonensis-specific virulence factor. In agreement with this hypothesis, it is shown herein that the intravenous injection of BALB/c mice with L. amazonensis amastigote extract (LaE), and not with L. braziliensis extract, confers susceptibility to L. braziliensis infection. This effect was associated with high circulating levels of IgG1 anti-L. amazonensis antibodies and with an increase in IL-4 and a decrease in IFN-γ production by draining lymph node cells. Moreover, the effect was absent in IL-4 - knockout mice. The biological activity in the LaE was not mediated by amphiphilic molecules and was inhibited by pre-treatment of the extract with irreversible serine-protease inhibitors. These findings indicate that the LaE contains a virulence-related factor that: (i) enhances the Leishmania infection by promoting Th2-type immune responses; (ii) is not one of the immunomodulatory Leishmania molecules described so far; (iii) is either a serine protease or its effect depends on that protease activity. In addition to being Leishmania-species specific, the infection-enhancing activity was also shown to depend on the host genetic makeup, as LaE injections did not affect the susceptibility of C57Bl/6 mice to L. braziliensis infection. The identification of Leishmania molecules with infection-enhancing activity could be important for the development of a vaccine, since the up- or down-modulation of the immune response against a virulence factor could well contribute to controlling the infection. |
| PMID: 21173308 [PubMed - as supplied by publisher] | |
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| 2. | Mol Cell Biol. 2010 Dec 20. [Epub ahead of print]The kinetoplast duplication cycle in Trypanosoma brucei is orchestrated by cytoskeleton-mediated cell morphogenesis.Gluenz E, Povelones ML, Englund PT, Gull K.Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK; Department of Biological Chemistry, Johns Hopkins Medical School, Baltimore, MD 21205 USA. AbstractThe mitochondrial DNA of Trypanosoma brucei is organised in a complex structure called the kinetoplast. In this study we define the complete kinetoplast duplication cycle in T. brucei based on three-dimensional reconstructions from serial-section electron micrographs. This structural model was enhanced by analyses of the replication process of DNA maxi- and minicircles. Novel insights were obtained about the earliest and latest stages of kinetoplast duplication. We show that kinetoplast S-phase occurs concurrent with the re-positioning of the new basal body from the anterior to the posterior side of the old flagellum. This emphasises the role of basal body segregation in kinetoplast division and suggests a possible mechanism for driving the rotational movement of the kinetoplast during minicircle replication. Fluorescence in situ hybridisation with minicircle and maxicircle-specific probes showed that maxicircle DNA is stretched out between segregated minicircle networks, indicating that maxicircle segregation is a late event in the kinetoplast duplication cycle. This new view of the complexities of kinetoplast duplication emphasises the dependencies between dynamic remodelling of the cytoskeleton and inheritance of the mitochondrial genome. |
| PMID: 21173163 [PubMed - as supplied by publisher] | |
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| 3. | Int J Parasitol. 2010 Dec 17. [Epub ahead of print]Ac tivity and turnover of eosinophil and neutrophil granulocytes are altered in visceral leishmaniasis.Elshafie AI, Ahlin E, Håkansson LD, Elghazali G, Safi SH, Rönnelid J, Venge P.Unit of Clinical Immunology, Uppsala University, Uppsala, Sweden; Department of Clinical Pathology, Alribat University Hospital, Khartoum, Sudan. AbstractVisceral leishmaniasis (VL) is a health issue in Sudan. Our aim was to investigate the involvement of eosinophils and neutrophils in VL by serum and plasma measurements of eosinophil cationic protein (ECP) and myeloperoxidase (MPO) and some key cytokines and chemokines. Blood was collected from 125 VL patients and 181 healthy Sudanese controls from the same rural area. Results showed reduced eosinophil and neutrophil counts in the VL group (P = 0.0001and P = 0.002, respectively). Serum ECP levels were higher in the controls (P < 0.0001), while plasma MPO levels were higher in the VL group (P < 0.0001). Levels of IL-5, granulocyte macrophage-colony stimulating factor (GM-CSF) and IL-17 were increased among the VL group (P < 0.0001, P = 0.017 and P = 0.03, respectively), whereas eotaxin and IL-8 levels were reduced (P < 0.0001 and P = 0.002, respectively). Positive correlations were found between IL-8 and ECP/MPO (P < 0.0001). We conclude that eosinophil and neutrophil turnover and activity are increased in subjects in rural areas of Sudan. In VL the turnover was further increased, but the relatively low secretory activity of eosinophils and neutrophils in VL may relate to the reduced production and availability of the chemokines eotaxin and IL-8. The combined assay of ECP and MPO in serum and plasma provides further insight into the mechanisms of eosinophil and neutrophil involvement in disease and constitutes a novel approach to the study of disease processes. Copyright © 2010. Published by Elsevier Ltd. |
| PMID: 21172349 [PubMed - as supplied by publisher] | |
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| 4. | BMC Infect Dis. 2010 Dec 20;10(1):358. [Epub ahead of print]High levels of T lymphocyte activation in Leishmania-HIV-1 co-infected individuals despite low HIV viral load.Santos-Oliveira JR, Giacoia-Gripp CB, Alexandrino-de-Oliveira PA, Amato VS, Lindoso JA, Goto H, Oliveira-Neto MP, Mattos MS, Grinsztejn B, Morgado MG, Da-Cruz AM.AbstractABSTRACT: BACKGROUND: Concomitant infections may influence HIV progression by causing chronic activation leading to decline in T-cell function. In the Americas, visceral (AVL) and tegumentary leishmaniasis (ATL) have emerged as important opportunistic infections in HIV-AIDS patients and both of those diseases have been implicated as potentially important co-factors in disease progression. We investigated whether leishmaniasis increases lymphocyte activation in HIV-1 co-infected patients. This might contribute to impaired cellular immune function. Methods: To address this issue we analyzed CD4+ T absolute counts and the proportion of CD8+ T cells expressing CD38 in Leishmania/HIV co-infected patients that recovered after anti-leishmanial therapy. Results: We found that, despite clinical remission of leishmaniasis, AVL co-infected patients presented a more severe immunossupression as suggested by CD4+ T cell counts under 200 cells/mm3, differing from ATL/HIV-AIDS cases that tends to show higher lymphocytes levels (over 350 cells/ mm3). Furthermore, five out of nine, AVL/HIV-AIDS presented low CD4+ T cell counts in spite of low or undetectable viral load. Expression of CD38 on CD8+ T lymphocytes was significantly higher in AVL or ATL/HIV-AIDS cases compared to HIV/AIDS patients without leishmaniasis or healthy subjects. Conclusions: Leishmania infection can increase the degree of immune system activation in individuals concomitantly infected with HIV. In addition, AVL/HIV-AIDS patients can present low CD4+ T cell counts and higher proportion of activated T lymphocytes even when HIV viral load is suppressed under HAART. This fact can cause a misinterpretation of these laboratorial markers in co-infected patients. |
| PMID: 21171992 [PubMed - as supplied by publisher] | |
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| 5. | Parasit Vectors. 2010 Dec 20;3(1):121. [Epub ahead of print]Geographical di stribution of American cutaneous leishmaniasis and its phlebotomine vectors (Diptera: Psychodidae) in the state of Sao Paulo, Brazil.Shimabukuro PH, Silva TR, Fonseca FO, Baton LA, Galati EA.AbstractABSTRACT: BACKGROUND: American cutaneous leishmaniasis (ACL) is a re-emerging disease in the state of Sao Paulo, Brazil. It is important to understand both the vector and disease distribution to help design control strategies. As an initial step in applying geographic information systems (GIS) and remote sensing (RS) tools to map disease-risk, the objectives of the present work were to: (i) produce a single database of species distributions of the sand fly vectors in the state of Sao Paulo, (ii) create combined distributional maps of both the incidence of ACL and its sand fly vectors, and (iii) thereby provide individual municipalities with a source of reference material for work carried out in their area. RESULTS: A database containing 910 individual records of sand fly occurrence in the state of Sao Paulo, from 37 different sources, was compiled. These records date from between 1943 to 2009, and describe the presence of at least one of the six incriminated or suspected sand fly vector species in 183/645 (28.4%) municipalities. For the remaining 462 (71.6%) municipalities, we were unable to locate records of any of the six incriminated or suspected sand fly vector species (Nyssomyia intermedia, N. neivai, N. whitmani, Pintomyia fischeri, P. pessoai and Migonemyia migonei). The distribution of each of the six incriminated or suspected vector species of ACL in the state of Sao Paulo were individually mapped and overlaid on the incidence of ACL for the period 1993 to 1995 and 1998 to 2007. Overall, the maps reveal that the six sand fly vector species analyzed have unique and heterogeneous, although often overlapping, distributions. Several sand fly species - Nyssomyia intermedia and N. neivai - are highly localized, while the other sand fly species - N. whitmani, M. migonei, P. fischeri and P. pessoai - are much more broadly distributed. ACL has been reported in 160/183 (87.4%) of the municipalities with records for at least one of the six incriminated or suspected sand fly vector species, while there are no records of any of these sand fly species in 318/478 (66.5%) municipalities with ACL. CONCLUSIONS: The maps produced in this work provide basic data on the distribution of the six incriminated or suspected sand fly vectors of ACL in the state of Sao Paulo, and highlight the complex and geographically heterogeneous pattern of ACL transmission in the region. Further studies are required to clarify the role of each of the six suspected sand fly vector species in different regions of the state of Sao Paulo, especially in the majority of municipalities where ACL is present but sand fly vectors have not yet been identified. |
| PMID: 21171969 [PubMed - as supplied by publisher] | |
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| 6. | BMC Genomics. 2010 Dec 1;11 Suppl 3:S1.Effector prediction in host-pathogen interaction based on a Markov model of a ubiquitous EPIYA motif.Xu S, Zhang C, Miao Y, Gao J, Xu D.Department of Gastroenterology, the First Affiliated Hospital of Nanjing Medical University, Jiangsu 210029, China. xushfu@njmu.edu.cn. AbstractABSTRACT : BACKGROUND : Effector secretion is a common strategy of pathogen in mediating host-pathogen interaction. Eight EPIYA-motif containing effectors have recently been discovered in six pathogens. Once these effectors enter host cells through type III/IV secretion systems (T3SS/T4SS), tyrosine in the EPIYA motif is phosphorylated, which triggers effectors binding other proteins to manipulate host-cell functions. The objectives of this study are to evaluate the distribution pattern of EPIYA motif in broad biological species, to predict potential effectors with EPIYA motif, and to suggest roles and biological functions of potential effectors in host-pathogen interactions. RESULTS : A hidden Markov model (HMM) of five amino acids was built for the EPIYA-motif based on the eight known effectors. Using this HMM to search the non-redundant protein database containing 9,216,047 sequences, we obtained 107,231 sequences with at least one EPIYA motif occurrence and 3115 sequences with multiple repeats of the EPIYA motif. Although the EPIYA motif exists among broad species, it is significantly over-represented in some particular groups of species. For those proteins containing at least four copies of EPIYA motif, most of them are from intracellular bacteria, extracellular bacteria with T3SS or T4SS or intracellular protozoan parasites. By combining the EPIYA motif and the adjacent SH2 binding motifs (KK, R4, Tarp and Tir), we built HMMs of nine amino acids and predicted many potential effectors in bacteria and protista by the HMMs. Some potential effectors for pathogens (such as Lawsonia intracellularis, Plasmodium falciparum and Leishmania major) are suggested. CONCLUSIONS : Our study indicates that the EPIYA motif may be a ubiquitous functional site for effectors that play an important pathogenicity role in mediating host-pathogen interactions. We suggest that some intracellular protozoan parasites could secrete EPIYA-motif containing effectors through secretion systems similar to the T3SS/T4SS in bacteria. Our predicted effectors provide useful hypotheses for further studies. |
| PMID: 21143776 [PubMed - in process] | |
| 7. | Expert Rev Mol Diagn. 2010 Sep;10(6):705-7.Shed acute-phase antigen protein in an ELISA system for unequivocal diagnosis of congenital Chagas disease.Russomando G, Sánchez Z, Meza G, de Guillen Y. Free Article |
| PMID: 20843193 [PubMed - indexed for MEDLINE] | |
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| 8. | Curr Opin Microbiol. 2010 Aug;13(4):466-72. Epub 2010 Jun 30.Composition and sensory function of the trypanosome flagellar memb rane.Maric D, Epting CL, Engman DM.Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA. Comment in: AbstractA cilium is an extension of the cell that contains an axonemal complex of microtubules and associated proteins bounded by a membrane which is contiguous with the cell body membrane. Cilia may be nonmotile or motile, the latter having additional specific roles in cell or fluid movement. The term flagellum refers to the motile cilium of free-living single cells (e.g. bacteria, archaea, spermatozoa, and protozoa). In eukaryotes, both nonmotile and motile cilia possess sensory functions. The ciliary interior (cilioplasm) is separated from the cytoplasm by a selective barrier that prevents passive diffusion of molecules between the two domains. The sensory functions of cilia reside largely in the membrane and signals generated in the cilium are transduced into a variety of cellular responses. In this review we discuss the structure and biogenesis of the cilium, with special attention to the trypanosome flagellar membrane, its lipid and protein composition and its proposed roles in sensing and signaling. Copyright 2010 Elsevier Ltd. All rights reserved. |
| PMID: 20580599 [PubMed - indexed for MEDLINE] | |
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| 9. | Curr Opin Microbiol. 2010 Aug;13(4):450-2. Epub 2010 Jun 25.The peculiarities of flagella in parasitic protozoa.Bastin P.Comment on: |
| PMID: 20579933 [PubMed - indexed for MEDLINE] | |
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| 10. | Int J Parasitol. 2010 Oct;40(12):1389-94. Epub 2010 Apr 18.Polyamine biosynthesis in Phytomonas: biochemical characterisation of a ve ry unstable ornithine decarboxylase.Marcora MS, Cejas S, González NS, Carrillo C, Algranati ID.Fundación Instituto Leloir, IIBBA - CONICET, Buenos Aires, Argentina. AbstractThe metabolism of polyamines as well as their functions as growth regulators in plants have been extensively studied for many years. However, almost nothing is known about the biosynthesis and roles of these substances in Phytomonas spp., parasites of several plants. We have used HPLC and electrophoretic analyses to investigate the presence and metabolism of polyamines in Phytomonas Jma strain, detecting both putrescine and spermidine but not spermine. Experiments carried out by incubation of intact parasites with labelled ornithine or putrescine showed the formation of radioactive putrescine or spermidine, respectively. These results indicated that Phytomonas Jma can synthesise these polyamines through the action of ornithine decarboxylase (ODC) and spermidine synthase. On the other hand, we could not detect the conversion of arginine to agmatine, suggesting the absence of arginine decarboxylase (ADC) in Phytomonas. However, we cannot ensure the complete absence of this enzymatic activity in the parasite. Phytomonas ODC required pyridoxal 5'-phosphate for maximum activity and was specifically inhibited by α-difluoromethylornithine. The metabolic turnover of the enzyme was very high, with a half-life of 10-15 min, one of the shortest found among all ODC enzymes studied to date. The parasite proteasome seems to be involved in degradation of the enzyme, since Phytomonas ODC can be markedly stabilized by MG-132, a well known proteasome inhibitor. The addition of polyamines to Phytomonas cultures did not decrease ODC activity, strongly suggesting the possible absence of antizyme in this parasite. Copyright © 2010 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved. |
| PMID: 20406645 [PubMed - indexed for MEDLINE] | |
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