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Sent on Wednesday, 2010 Oct 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. | Trop Med Int Health. 2010 Nov;15(11):1281-8.Population movement: a key factor in the epidemiology of neglected tropical diseases.Aagaard-Hansen J, Nombela N, Alvar J.Steno Health Promotion Center, Steno Diabetes Center, Gentofte, Denmark. AbstractThis review provides an overview of the complex ways in which population movements are linked to spread and control of neglected tropical diseases – often exacerbated by insufficient medical services and sanitary infrastructure. A new typology of population movements is suggested which builds on previous work but offers a more comprehensive typology based on the variables of 'onset', 'cause', 'direction' and 'motivation'. Schistosomiasis and leishmaniasis provide examples of the intricate ways in which population movements may play a role. A thorough and context-specific understanding of these patterns combined with the ability and will to launch targeted public health interventions is needed to achieve adequate control of neglected tropical diseases as well as other infectious diseases. |
| PMID: 20976871 [PubMed - in process] | |
| 2. | Arch Virol. 2010 Oct 26. [Epub ahead of print]Trichomonasvirus: a new genus of protozoan viruses in the family Totiviridae.Goodman RP, Ghabrial SA, Fichorova RN, Nibert ML.Harvard Medical School, 25 Shattuck Street, Boston, MA, 02115, USA. AbstractThe family Totiviridae includes a number of viruses with monosegmented dsRNA genomes and isometric virions that infect either fungi or a number of medically important protozoan parasites such as Leishmania and Giardia. A new genus, Trichomonasvirus, was recently approved for this family. Its name is based on the genus of its host organism, Trichomonas vaginalis, a protozoan parasite that colonizes the human genitourinary mucosa and is the most common non-viral sexually transmitted infection in the world. The type species of this new genus is Trichomonas vaginalis virus 1. Distinguishing characteristics of the new genus include infection of a human sexually transmitted parasite, stable mixed infection with more than one distinct Trichomonasvirus species, and sequence-based phylogenetic divergence that distinguishes it from all other family members. |
| PMID: 20976609 [PubMed - as supplied by publisher] | |
| 3. | J Nucleic Acids. 2010 Oct 4;2010:840768.Overview of DNA Repair in Trypanosoma cruzi, Trypanosoma brucei, and Leishmania major.Passos-Silva DG, Rajão MA, Nascimento de Aguiar PH, Vieira-da-Rocha JP, Machado CR, Furtado C.Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, 31270-901 Belo Horizonte, MG, Brazil. AbstractA wide variety of DNA lesions arise due to environmental agents, normal cellular metabolism, or intrinsic weaknesses in the chemical bonds of DNA. Diverse cellular mechanisms have evolved to maintain genome stability, including mechanisms to repair damaged DNA, to avoid the incorporation of modified nucleotides, and to tolerate lesions (translesion synthesis). Studies of the mechanisms related to DNA metabolism in trypanosomatids have been very limited. Together with recent experimental studies, the genome sequencing of Trypanosoma brucei, Trypanosoma cruzi, and Leishmania major, three related pathogens with different life cycles and disease pathology, has revealed interesting features of the DNA repair mechanism in these protozoan parasites, which will be reviewed here. |
| PMID: 20976268 [PubMed - in process] | |
| 4. | PLoS Pathog. 2010 Oct 14;6(10):e1001154.Direct Visualization of Peptide/MHC Complexes at the Surface and in the Intracellular Compartments of Cells Infected In Vivo by Leishmania major.Muraille E, Gounon P, Cazareth J, Hoebeke J, Lippuner C, Davalos-Misslitz A, Aebischer T, Muller S, Glaichenhaus N, Mougneau E.Institut de Pharmacologie Moléculaire et Cellulaire, INSERM U924, Valbonne, France. AbstractProtozoa and bacteria infect various types of phagocytic cells including macrophages, monocytes, dendritic cells and eosinophils. However, it is not clear which of these cells process and present microbial antigens in vivo and in which cellular compartments parasite peptides are loaded onto Major Histocompatibility Complex molecules. To address these issues, we have infected susceptible BALB/c (H-2(d)) mice with a recombinant Leishmania major parasite expressing a fluorescent tracer. To directly visualize the antigen presenting cells that present parasite-derived peptides to CD4(+) T cells, we have generated a monoclonal antibody that reacts to an antigenic peptide derived from the parasite LACK antigen bound to I-A(d) Major Histocompatibility Complex class II molecule. Immunogold electron microscopic analysis of in vivo infected cells showed that intracellular I-A(d)/LACK complexes were present in the membrane of amastigote-containing phagosomes in dendritic cells, eosinophils and macrophages/monocytes. In both dendritic cells and macrophages, these complexes were also present in smaller vesicles that did not contain amastigote. The presence of I-A(d)/LACK complexes at the surface of dendritic cells, but neither on the plasma membrane of macrophages nor eosinophils was independently confirmed by flow cytometry and by incubating sorted phagocytes with highly sensitive LACK-specific hybridomas. Altogether, our results suggest that peptides derived from Leishmania proteins are loaded onto Major Histocompatibility Complex class II molecules in the phagosomes of infected phagocytes. Although these complexes are transported to the cell surface in dendritic cells, therefore allowing the stimulation of parasite-specific CD4(+) T cells, this does not occur in other phagocytic cells. To our knowledge, this is the first study in which Major Histocompatibility Complex class II molecules bound to peptides derived from a parasite protein have been visualized within and at the surface of cells that were infected in vivo. |
| PMID: 20976202 [PubMed - in process] | |
| 5. | PLoS Pathog. 2010 Oct 14;6(10):e1001148.Leishmania-Induced Inactivation of the Macrophage Transcription Factor AP-1 Is Mediated by the Parasite Metalloprotease GP63.Contreras I, Gómez MA, Nguyen O, Shio MT, McMaster RW, Olivier M.Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada. AbstractLeishmania parasites have evolved sophisticated mechanisms to subvert macrophage immune responses by altering the host cell signal transduction machinery, including inhibition of JAK/STAT signalling and other transcription factors such as AP-1, CREB and NF-κB. AP-1 regulates pro-inflammatory cytokines, chemokines and nitric oxide production. Herein we show that upon Leishmania infection, AP-1 activity within host cells is abolished and correlates with lower expression of 5 of the 7 AP-1 subunits. Of interest, c-Jun, the central component of AP-1, is cleaved by Leishmania. Furthermore, the cleavage of c-Jun is dependent on the expression and activity of the major Leishmania surface protease GP63. Immunoprecipitation of c-Jun from nuclear extracts showed that GP63 interacts, and cleaves c-Jun at the perinuclear area shortly after infection. Phagocytosis inhibition by cytochalasin D did not block c-Jun down-regulation, suggesting that internalization of the parasite might not be necessary to deliver GP63 molecules inside the host cell. This observation was corroborated by the maintenance of c-Jun cleavage upon incubation with L. mexicana culture supernatant, suggesting that secreted, soluble GP63 could use a phagocytosis-independent mechanism to enter the host cell. In support of this, disruption of macrophage lipid raft microdomains by Methyl β-Cyclodextrin (MβCD) partially inhibits the degradation of full length c-Jun. Together our results indicate a novel role of the surface protease GP63 in the Leishmania-mediated subversion of host AP-1 activity. |
| PMID: 20976196 [PubMed - in process] | |
| 6. | Drug Discov Today. 2010 Oct 22. [Epub ahead of print]Metal-based drugs for malaria, trypanosomiasis and leishmaniasis: recent achievements and perspectives.Navarro M, Gabbiani C, Messori L, Gambino D.Centro de Química, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela. AbstractTropical diseases today constitute a major health problem and a big challenge for drug discovery. Because of the limited arsenal of effective antiparasitic agents and the frequent appearance of chemoresistance, there is an urgent and continuous need to develop new drugs against these ailments. Metal compounds still offer excellent opportunities to find new 'leads' against the major protozoan diseases such as malaria, leishmaniasis and trypanosomiasis. A few metal-based drugs are already available in this therapeutic area, and others are currently being developed. Recent progress in parasite genomics and the identification of a few biomolecular targets hold great promise for the discovery of new 'mechanism-based' antiparasitic metallodrugs. The trends and perspectives for this exciting research field are outlined here. Copyright © 2010. Published by Elsevier Ltd. |
| PMID: 20974285 [PubMed - as supplied by publisher] | |
| 7. | Mol Biochem Parasitol. 2010 Oct 22. [Epub ahead of print]Highly specific methyl-end fatty-acid desaturases of trypanosomatids.Alloatti A, Uttaro AD.Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Santa Fe, Argentina. AbstractA detailed analysis of the trypanosomatidś genome projects revealed the presence of genes predicted to encode fatty-acid desaturases of the methyl-end type (MED). After cloning and functional characterization of all identified genes, it can be concluded that Trypanosoma cruzi contains two MEDs with oleate desaturase (OD) activities whereas Leishmania major contains one OD and two active linoleate desaturases (LD). All characterized ODs are highly specific for oleate (18:1Δ9) as substrate, presenting a ν+3 regioselectivity, although palmitoleate (16:1Δ9) can be desaturated as well, but to a lesser extent. L. major LD appears to use exclusively linoleate (18:2n-6), converting it into α-linolenate (18:3n-3). This strong specificity assures no further conversion of polyunsaturated fatty acids (PUFAs) of the n-6 series into the n-3 series, downstream in the PUFA biosynthesis pathway. This characterization completes the identification of all enzymes involved in PUFA biosynthesis in a parasitic protist. Differently from their T. brucei orthologue, T. cruzi and L. major ODs were more active when expressed either, in the presence of trienoic fatty acids or at higher temperatures. This could be evidence for a differential post-translational regulation of these enzymes as a result of direct sensing of environmentally-dependent parameters such as membrane fluidity. Copyright © 2010. Published by Elsevier B.V. |
| PMID: 20974196 [PubMed - as supplied by publisher] | |
| 8. | J Biol Chem. 2010 Oct 1;285(40):30906-17. Epub 2010 Jul 20.Acylation-dependent export of Trypanosoma cruzi phosphoinositide-specific phospholipase C to the outer surface of amastigotes.de Paulo Martins V, Okura M, Maric D, Engman DM, Vieira M, Docampo R, Moreno SN.Department of Cellular Biology, University of Georgia, Center for Tropical and Emerging Global Diseases, Athens, Georgia 30602, USA. AbstractPhosphoinositide phospholipase C (PI-PLC) plays an essential role in cell signaling. A unique Trypanosoma cruzi PI-PLC (TcPI-PLC) is lipid-modified in its N terminus and localizes to the plasma membrane of amastigotes. Here, we show that TcPI-PLC is located onto the extracellular phase of the plasma membrane of amastigotes and that its N-terminal 20 amino acids are necessary and sufficient to target the fused GFP to the outer surface of the parasite. Mutagenesis of the predicted acylated residues confirmed that myristoylation of a glycine residue in the 2nd position and acyl modification of a cysteine in the 4th but not in the 8th or 15th position of the coding sequence are required for correct plasma membrane localization in T. cruzi epimastigotes or amastigotes. Interestingly, mutagenesis of the cysteine at the 8th position increased its flagellar localization. When expressed as fusion constructs with GFP, the N-terminal 6 and 10 amino acids fused to GFP are predominantly located in the cytosol and concentrated in a compartment that co-localizes with a Golgi complex marker. The N-terminal 20 amino acids of TcPI-PLC associate with lipid rafts when dually acylated. Taken together, these results indicate that N-terminal acyl modifications serve as a molecular addressing system for sending TcPI-PLC to the outer surface of the cell. |
| PMID: 20647312 [PubMed - indexed for MEDLINE] | |
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