Wednesday, June 10, 2009

What's new for 'Trypanosomatids' in PubMed

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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 -5 of 5

1: J Pharm Pharmacol. 2009 Jun;61(6):801-8.

Antitrypanosomal and cytotoxic activities of pyrrolizidine alkaloid-producing plants of Ethiopia.

Nibret E, Sporer F, Asres K, Wink M.

Email: wink@uni-hd.de.

Objectives The objective was to determine the in-vitro effect of extracts from 19 Ethiopian plant species and four pure pyrrolizidine alkaloids on bloodstream forms of Trypanosoma brucei brucei and human leukaemia HL-60 cells. Methods Crude plant extracts were prepared using methanol and dichloromethane. The alkaloidal extracts from Solanecio angulatus flowers were prepared with and without zinc reduction using the acid-base extraction method. Cell proliferation inhibitory activity of the extracts and compounds was assessed using Alamarblue. Key findings The most active extract was the dichloromethane extract of Solanecio angulatus flowers, with an IC50 value of 12.17 mug/ml. The best selectivity index (SI > 41.08) was obtained for the same extract determined with HL-60 cells. The reduced alkaloidal extract prepared from S. angulatus flowers and after acid-base extraction showed more antitrypanosomal activity than unreduced alkaloidal extract with an IC50 value of 14.35 mug/ml and with a selectivity index of 12.23. The second most active extract was the dichloromethane extract of Crotalaria phillipsiae twigs with an IC50 value of 12.67 mug/ml and a selectivity index of 34.35. Most of the other extracts tested showed moderate antitrypanosomal activities to variable extents. Among the four pure pyrrolizidine alkaloids tested, senecionine showed moderate antitrypanosomal activity with an IC50 value of 41.78 mug/ml. Conclusions Solanecio angulatus (flowers) and Crotalaria phillipsiae (twigs) could serve as sources of novel trypanocidal compounds for the treatment of trypanosomiasis.

PMID: 19505372 [PubMed - in process]

2: Biomedica. 2008 Dec;28(4):616-26.LinkOut

[Evaluation of TcH2AF-R and S35-S36 primers in PCR tests for the detection of Trypanosoma cruzi in mouse cardiac tissue]

[Article in Spanish]

Barrera YK, Guevara JM, Pavía PX, Montilla M, Nicholls RS, Parra E, Puerta CJ.

Laboratorio de Parasitología Molecular, Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, D.C., Colombia.

INTRODUCTION: Heart transplant is a therapeutic option in the treatment of chagasic cardiomyopathy. For early detection of Chagas reactivation cases, the use of PCR tests using endomyocardial biopsies has been proposed. Development of an animal model will be the first step in evaluating the applicability of this approach. OBJECTIVE: PCR tests based on the TcH2AF-R and S35-S36 primers were evaluated for the detection of T. cruzi in heart tissue of mice experimentally infected with the parasite. MATERIALS AND METHODS: Two groups of ICR mice of 15 and 10 individuals were infected by intraperitoneal injection with 0.3 ml of PBS containing 1 x 10(6) trypomastigotes of the MHOM/CO/2001/D.A. (T. cruzi I) strain or 1 x 10(4) trypomastigotes of MHOM/BR/00/Y (T. cruzi II) strain. Parasitemia and cardiac parasitic infection were determined at 30, 60 (acute model), 100 and 150 (chronic model) days by means of histopathological examination and by PCR, using the TcH2AF-R and S35-S36 primers. RESULTS: The histopathological findings revealed alterations in the heart and the presence of intracellular amastigotes in acute and chronic models. In contrast to parasitemia levels and histopathological analyses, S35-S36 PCR detected infections in mice that were infected with either parasite strain. TcH2AF-R PCR detected T. cruzi I-infected mice earlier and more frequently than inspection for parasitemia or histopathological examination. CONCLUSIONS: Applying PCR tests with both primers proved superior for Chagas disease confirmation over currently standard detection methods.

PMID: 19462567 [PubMed - indexed for MEDLINE]

3: Biochem Biophys Res Commun. 2009 Jun 26;384(2):265-9. Epub 2009 May 4.Click here to read LinkOut

Lysosomal exocytosis: an important event during invasion of lamp deficient cells by extracellular amastigotes of Trypanosoma cruzi.

Gaspar EB, Mortara RA, Andrade LO, da Silva CV.

Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, Rua Botucatu 862, 6 Degrees Andar, São Paulo 04023-062 SP, Brazil.

Trypanosoma cruzi is an obligate intracellular organism in vertebrate hosts. Lysosomes are involved in parasite invasion. LAMP-1 and LAMP-2 are the most abundant glycoproteins of the lysosomal membrane. This study is the first report on the invasion of T. cruzi extracellular amastigotes (EA) in single LAMP-1 or LAMP-2 knockouts, respectively, or in two independent LAMP-1/2 double-knockout cell lines. When compared to their respective wild type clones, the EA show higher infectivity in LAMP-2 knockouts, but no difference was seen in LAMP-1 knockout cells. Similarly, EA invasion rate was higher for one of the double knockout clones but not for the other. Higher lysosomal exocytosis correlated with a higher invasion rate and early lysosomal marker acquisition. These findings suggest that lysosomal exocytosis is important to EA cell invasion. Also, phagolysosome maturation in knockout cell lines differed from previous results revealing that EA enter cells by a mechanism other than receptor-mediated phagocytosis.

PMID: 19406103 [PubMed - indexed for MEDLINE]

4: Parasitology. 2008 Aug;135(9):1101-10. Epub 2008 Jul 14.Click here to read Cited in PMC, LinkOut

Were class C iron-containing superoxide dismutases of trypanosomatid parasites initially imported into a complex plastid? A hypothesis based on analyses of their N-terminal targeting signals.

Bodył A, Mackiewicz P.

Department of Biodiversity and Evolutionary Taxonomy, Zoological Institute, University of Wrocław, ul. Przybyszewskiego 63/77, 51-148 Wrocław, Poland. bodyl@biol.uni.wroc.pl

Trypanosomatid parasites possess 2 distinct iron-containing superoxide dismutases (Fe-SODs) designated SODA and SODC, both of which are targeted to their mitochondria. In contrast to SODAs that carry typical mitochondrial transit peptides, SODCs have highly unusual mitochondrial targeting signals. Our analyses clearly show that these pre-sequences are bipartite possessing a signal peptide-like domain followed by a transit peptide-like domain. Consequently, they resemble N-terminal extensions of proteins targeted to multi-membrane plastids, suggesting that trypanosomatids once contained a eukaryotic alga-derived plastid. Further support for this hypothesis comes from striking similarities in length, hydropathy profile, and amino acid composition of SODC pre-sequences to those of Euglena and dinoflagellate plastid proteins. To account for these data, we propose that the Trypanosomatidae initially possessed a gene encoding a mitochondrial Fe-SOD with a classical mitochondrial transit peptide. Before or after plastid acquisition, a gene duplication event gave rise to SODA and SODC. In a subsequent evolutionary step a signal peptide was linked to SODC, enabling its import into the plastid. When the trypanosomatid plastid subsequently was lost, natural selection favoured adaptation of the SODC N-terminal signal as a mitochondrial transit peptide and re-targeting to the mitochondrion.

PMID: 18620621 [PubMed - indexed for MEDLINE]

5: Parasitology. 2008 Aug;135(9):1093-100. Epub 2008 Jul 14.Click here to read LinkOut

Protease expression analysis in recently field-isolated strains of Trypanosoma cruzi: a heterogeneous profile of cysteine protease activities between TC I and TC II major phylogenetic groups.

Fampa P, Lisboa CV, Jansen AM, Santos AL, Ramirez MI.

Laboratório de Biologia Molecular de Tripanosomatídeos e Flebotomíneos, Instituto Oswaldo Cruz, Fiocruz. Av. Brasil, 4365, 21045-900, Rio de Janeiro, Brazil.

Protease expression among TCI and TCII field isolates was analysed. Gelatin-containing gels revealed hydrolysis bands with molecular masses ranging from 45 to 66 kDa. The general protease expression profile showed that TCII isolates presented higher heterogeneity compared to TCI. By utilizing protease inhibitors, we showed that all active proteases at acid pH are cysteine-proteases and all proteases active at alkaline pH are metalloproteases. However, the expression of cruzipain, the T. cruzi major cysteine-protease, did not reproduce a heterogeneous TCII cysteine zymogram profile. Dendogram analyses based on presence/absence matrices of proteases and cruzipain bands showed a TCI separation from the TCII group with 50-60% similarity. We suggest that the observed cysteine protease diversification contributes to differential host infection between TCI and II genotypes.

PMID: 18620619 [PubMed - indexed for MEDLINE]

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