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Sent on Tuesday, 2009 Oct 13Search kinetoplastids OR kinetoplastid OR Kinetoplastida OR "trypanosoma brucei" OR leishmania OR brucei OR leishmaniasis OR "African trypanosomiasis"
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| PubMed Results |
- 1: Mem Inst Oswaldo Cruz. 2009 Aug;104(5):801-804.
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Visceral leishmaniasis in border areas: clustered distribution of phlebotomine sand flies in Clorinda, Argentina.
Centro Nacional de Diagnóstico e Investigación en Endemo-epidemias, Buenos Aires, Argentina.
Three years after the first report of Lutzomyia longipalpis in Clorinda, Argentina, a border city near Asunción, Paraguay, the city was surveyed again. Lu. longipalpis was found clustered in the same neighbourhoods in 2007 as in 2004, even though the scattered distribution of canine visceral leishmaniasis was more related to the traffic of dogs through the border.
PMID: 19820846 [PubMed - as supplied by publisher]
- 2: Mem Inst Oswaldo Cruz. 2009 Aug;104(5):745-748.
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Molecular and biochemical characterisation of Trypanosoma cruzi phosphofructokinase.
Centro de Biotecnología, Instituto de Estudios Avanzados, Caracas, Venezuela.
The characterisation of the gene encoding Trypanosoma cruzi CL Brener phosphofructokinase (PFK) and the biochemical properties of the expressed enzyme are reported here. In contradiction with previous reports, the PFK genes of CL Brener and YBM strain T. cruzi were found to be similar to their Leishmania mexicana and Trypanosoma brucei homologs in terms of both kinetic properties and size, with open reading frames encoding polypeptides with a deduced molecular mass of 53,483. The predicted amino acid sequence contains the C-terminal glycosome-targeting tripeptide SKL; this localisation was confirmed by immunofluorescence assays. In sequence comparisons with the genes of other eukaryotes, it was found that, despite being an adenosine triphosphate-dependent enzyme, T. cruzi PFK shows significant sequence similarity with inorganic pyrophosphate-dependent PFKs.
PMID: 19820836 [PubMed - as supplied by publisher]
- 3: Mem Inst Oswaldo Cruz. 2009 Aug;104(5):695-702.
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Phlebotomine fauna (Diptera: Psychodidae) of an American cutaneous leishmaniasis endemic area in the state of Mato Grosso do Sul, Brazil.
Departamento de Patologia, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS, Brasil, 79070-900.
The occurrence of an outbreak of cutaneous leishmaniasis associated with Leishmania (Leishmania) amazonensis in the municipality of Bela Vista, state of Mato Grosso do Sul, Brazil, and the absence of information on its vectors in this area led the authors to undertake captures of phlebotomine sand flies, using Shannon traps and automatic CDC light traps, in domiciles, forested areas and animal shelters from February 2004-January 2006. A total of 808 specimens belonging to 18 sandfly species have been identified: Bichromomyia flaviscutellata,Brumptomyia avellari, Brumptomyia brumpti, Brumptomyia sp, Evandromyia aldafalcaoae, Evandromyia cortelezzii, Evandromyia evandroi, Evandromyia lenti, Evandromyia teratodes, Evandromyia termitophila, Lutzomyia longipalpis, Nyssomyia whitmani, Pintomyia christenseni, Psathyromyia aragaoi, Psathyromyia campograndensis, Psathyromyia punctigeniculata, Psathyromyia shannoni and Sciopemyia sordellii. The presence of Lu. longipalpis, Ny. whitmani and Bi. flaviscutellata, vectors of Leishmania chagasi, Leishmania braziliensis and L. amazonensis, respectively, has increased.
PMID: 19820827 [PubMed - as supplied by publisher]
- 4: Eukaryot Cell. 2009 Oct 9. [Epub ahead of print]
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Heterologous expression studies in yeast reveal two distinct trypanosomatid CaaX protease activities and identifies their potential targets.
Department of Biochemistry and Molecular Biology, The University of Georgia, 120 Green Street, Athens, GA 30602; Department of Biological Sciences, The University of Southern Mississippi, 118 College Drive, Hattiesburg, MS 39406.
The CaaX tetrapeptide motif typically directs three sequential post-translational modifications: namely, isoprenylation, proteolysis, and carboxyl methylation. In all eukaryotic systems evaluated to date, two CaaX proteases (Rce1 and Ste24/Afc1) have been identified. While the Trypanosoma brucei genome also encodes two putative CaaX proteases, the lack of detectable Tb Ste24 activity in trypanosome cell extracts has suggested that CaaX proteolytic activity within this organism is solely attributed to Tb Rce1 (20). In this study, we demonstrate that both Tb Rce1 and Tb Ste24 are enzymatically active when heterologously expressed in yeast. Using a-factor and GTPase reporters, we demonstrate that Tb Rce1 and Tb Ste24 possess partially overlapping specificities much like, but not identical to, their fungal and human counterparts. Of interest, a CaaX motif found on a trypanosomal Hsp40 protein was not cleaved by either Tb CaaX protease when examined in the context of the yeast a-factor reporter, but was cleaved by both in the context of the Hsp40 protein itself when evaluated using an in vitro radiolabeling assay. We further demonstrate that Tb Rce1 is sensitive to small molecules previously identified as inhibitors of the yeast and human CaaX proteases, and that a subset of these compounds disrupt Tb Rce1-dependent localization of our GTPase reporter in yeast. Together, our results suggest the conserved presence of two CaaX proteases in trypanosomatids, identify an Hsp40 protein as a substrate of both Tb CaaX proteases, support the potential use of small molecule CaaX protease inhibitors as tools for cell biological studies on the trafficking of CaaX proteins, and provide evidence that protein context influences Tb CaaX protease specificity.
PMID: 19820121 [PubMed - as supplied by publisher]
- 5: Int J Syst Evol Microbiol. 2009 Oct 9. [Epub ahead of print]
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Herpetomonas trimorpha sp. nov. (Trypanosomatidae, Kinetoplastida), a parasite of the biting midge Culicoides truncorum (Ceratopogonidae, Diptera).
Department of Parasitology, Charles University in Prague;
Monoxenous trypanosomatid Herpetomonas trimorpha sp. nov. was isolated from the digestive tract of the biting midge Culicoides truncorum (Ceratopogonidae, Diptera). This species forms three distinct morphotypes in culture; the small promastigote, the microflagellate promastigote, and the long promastigote. The last form is unique for the newly described species. Phylogenetic analyses of SSU rRNA and gGAPDH genes showed that H. trimorpha sp. nov. is the closest relative of H. ztiplika, another monoxenous trypanosomatid isolated from biting midges. However, morphological and RAPD analyses confirmed that Herpetomonas trimorpha sp. nov. is distinct from H. ztiplika.
PMID: 19819998 [PubMed - as supplied by publisher]
- 6: J Biochem. 2009 Oct 9. [Epub ahead of print]
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A Critical Role for highly Conserved GLU610 Residue of Oligopeptidase B from Trypanosoma Brucei in Thermal Stability.
Department of Biological Science and Technology, University of Tokushima Graduate School, 2-1 Minamijosanjima, Tokushima 770-8506, Japan.
Oligopeptidase B from Trypanosoma brucei (Tb OPB) is a virulence factor and therapeutic target in African sleeping sickness. Three glutamic acid residues at positions 607, 609 and 610 of the catalytic domain are highly conserved in the OPB subfamily. In this study, the roles of Glu(607), Glu(609) and Glu(610) in Tb OPB were investigated by site-directed mutagenesis. A striking effect on k(cat)/Km was obtained following mutation of Glu(607) to glutamine. In contrast, the heat stability of Tb OPB decreased markedly following the single mutation of Glu(610) to glutamine, although this mutation had significantly less effect on catalytic properties compared with the Glu(607) mutation. Although no differences were found in the tertiary and secondary structures between wild-type OPB and the E610Q mutant prior to heat treatment, the E610Q mutant is inactivated more rapidly than wild-type OPB following heat treatment in a manner correlating with its attendant structural changes. Trypsin digestion showed that the boundary regions between the beta-propeller and catalytic domain of the E610Q mutant are unfolded with heat treatment. It is concluded that Glu(607) is essential for the catalytic activity of Tb OPB and that Glu(610) plays a critical role in stabilization rather than catalytic activity despite their close proximity.
PMID: 19819899 [PubMed - as supplied by publisher]
- 7: Bioorg Med Chem. 2009 Sep 25. [Epub ahead of print]
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Antimalarial and antitrypanosomal activity of a series of amide and sulfonamide derivatives of a 2,5-diaminobenzophenone.
Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35032 Marburg, Germany.
Here, we describe a series of readily obtainable benzophenone derivatives with antimalarial and antitrypanosomal activity. The most active compounds display submicromolar activity against Plasmodium falciparum. Micromolar activity is obtained against Trypanosoma brucei. Main problem of the compounds is low selectivity. However, there are indications that separation of antimalarial and cytotoxic activity might by possible. In addition, some compounds inhibit human ABC transporter with nanomolar activity.
PMID: 19819706 [PubMed - as supplied by publisher]
- 8: Phytochemistry. 2009 Oct 9. [Epub ahead of print]
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Prenylation of aromatic compounds, a key diversification of plant secondary metabolites.
Laboratory of Plant Gene Expression, Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji 611-0011, Japan.
Prenylation plays a major role in the diversification of aromatic natural products, such as phenylpropanoids, flavonoids, and coumarins. This biosynthetic reaction represents the crucial coupling process of the shikimate or polyketide pathway providing an aromatic moiety and the isoprenoid pathway derived from the mevalonate or methyl erythritol phosphate (MEP) pathway, which provides the prenyl (isoprenoid) chain. In particular, prenylation contributes strongly to the diversification of flavonoids, due to differences in the prenylation position on the aromatic rings, various lengths of prenyl chain, and further modifications of the prenyl moiety, e.g., cyclization and hydroxylation, resulting in the occurrence of ca. 1000 prenylated flavonoids in plants. Many prenylated flavonoids have been identified as active components in medicinal plants with biological activities, such as anti-cancer, anti-androgen, anti-leishmania, and anti-nitric oxide production. Due to their beneficial effects on human health, prenylated flavonoids are of particular interest as lead compounds for producing drugs and functional foods. However, the gene coding for prenyltransferases that catalyze the key step of flavonoid prenylation have remained unidentified for more than three decades, because of the membrane-bound nature of these enzymes. Recently, we have succeeded in identifying the first prenyltransferase gene SfN8DT-1 from Sophora flavescens, which is responsible for the prenylation of the flavonoid naringenin at the 8-position, and is specific for flavanones and dimethylallyl diphosphate (DMAPP) as substrates. Phylogenetic analysis showed that SfN8DT-1 has the same evolutionary origin as prenyltransferases for vitamin E and plastoquinone. A prenyltransferase GmG4DT from soybean, which is involved in the formation of glyceollin, was also identified recently. This enzyme was specific for pterocarpan as its aromatic substrate, and (-)-glycinol was the native substrate yielding the direct precursor of glyceollin I. These enzymes are localized to plastids and the prenyl chain is derived from the MEP pathway. Further relevant genes involved in the prenylation of other types of polyphenol are expected to be cloned by utilizing the sequence information provided by the above studies.
PMID: 19819506 [PubMed - as supplied by publisher]
- 9: Infect Genet Evol. 2009 Oct 8. [Epub ahead of print]
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Population genetic structure of Central African Trypanosoma brucei gambiense isolates using microsatellite DNA markers.
Medical Research Centre, Institute of Medical Research and Medicinal Plant Studies (IMPM/MINRESI), P.O. Box 6163, Yaoundé, Cameroon; Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Cameroon.
Genetic variation of microsatellite loci is a widely used method for the analysis of population genetic structure of micro-organisms. Seven microsatellite markers were used here to characterize Trypanosoma bruceigambiense isolates from Central Africa sub-region in order to improve knowledge on the population genetic structure of this subspecies. These markers confirmed the low genetic polymorphism within Central African Trypanosoma brucei gambiense isolates from the same focus and strong differentiation between different foci. The presence of many multilocus genotypes of Trypanosoma brucei gambiense and the excess of heterozygotes found in this study play in favour of a clonal reproduction of this parasite. But some data may be indicative of a unique recombination event in one subsample. The high F(ST) value indicates low migration rates between Trypanosoma brucei gambiense subpopulations (foci). Very negative F(IS) suggests fairly small clonal population sizes of this pathogen in the different human trypanosomosis foci of Central Africa.
PMID: 19819349 [PubMed - as supplied by publisher]
- 10: Acta Trop. 2009 Oct 7. [Epub ahead of print]
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Experimental and field investigations on the role of birds as hosts of Leishmania infantum, with emphasis on the domestic chicken.
Dipartimento di Sanità Pubblica e Zootecnia, Università degli Studi di Bari, Strada Provinciale per Casamassima km 3, 70010 Valenzano (Bari), Italy.
In this study, 19 chickens were experimentally infected by Leishmania infantum and tissue samples, collected at different times, were cultured and subjected to conventional PCR and/or qPCR to assess their susceptibility to infection. In addition, 121 serum samples from rural chickens (n=73) and backyard birds (n=48) were tested for anti-L. infantum antibodies by indirect immunofluorescence test. All the 19 animals showed to be molecularly positive at least at one tissue sample. In particular, 26 tissue samples from the experimentally infected chickens were positive on conventional PCR and/or qPCR but no clinical signs or seroconversion were detected and all tissue cultures were negative. Accordingly, all serum samples from rural chickens were negative whereas four (8.4%) from game birds (three Anser anser and one Phasianus colchicus) were positive. These results indicate that chickens are not suitable hosts for L. infantum under experimental condition. The occurrence of anti-L. infantum antibodies in domestic gooses (A. anser) and in a pheasant (P. colchicus) points out their possible role in the epidemiology of visceral leishmaniasis.
PMID: 19818726 [PubMed - as supplied by publisher]
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