Friday, May 22, 2009

What's new for 'Trypanosomatids' in PubMed

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Sent on Friday, 2009 May 22
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 -3 of 3

1: Mol Biochem Parasitol. 2009 Aug;166(2):194-7.

Site-specific DNA double-strand breaks greatly increase stable transformation efficiency in Trypanosoma brucei.

Glover L, Horn D.

London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.

Genetic manipulation in African trypanosomes typically relies upon electroporation with chromosomal integration of DNA constructs by homologous recombination. Relatively little is known about chromosomal recombination and repair in these organisms however and low transformation efficiency and position effects can limit forward genetic approaches. In yeast and mammalian cells, site-specific DNA double-strand breaks (DSBs) stimulate targeted integration through homologous recombination-based repair where the exogenous DNA serves as the template. We have explored the effect of DSBs on targeted integration in bloodstream-form Trypanosoma brucei, focusing on the ribosomal RNA-spacer target commonly used to integrate recombinant constructs. DSB-repair within the ribosomal RNA tandem gene-repeats is likely dominated by single-strand annealing allowing approximately 80% of cells to survive the break. In the presence of exogenous DNA, transformation efficiency is increased approximately 250-fold by DSB-induction. In the example presented, more than 1% of cells that survive the procedure were transformed generating 80,000 transformants from a typical experiment.

PMID: 19459229 [PubMed - in process]

2: Trans R Soc Trop Med Hyg. 2009 May 18. [Epub ahead of print]Click here to read

Improvement of direct agglutination test (DAT) for laboratory diagnosis of visceral leishmaniasis in Brazil.

Oliveira E, Pedras MJ, Assis IE, Rabello A.

Clinical Research Laboratory, Centro de Pesquisa René Rachou, Fundação Oswaldo Cruz, Av. Augusto de Lima, 1715, Belo Horizonte, MG, 30190-002, Brazil.

We previously standardized the direct agglutination test (DAT) to detect anti-Leishmania chagasi promastigote antibodies (DAT-LPC) with good sensitivity and specificity for diagnosing visceral leishmaniasis (VL). In this paper, we present a technical upgrade by introducing some modifications into the antigen preparation. This antigen was evaluated in DAT (DAT-Mod) using 61 sera samples from VL patients and 96 samples from patients with other diseases. The DAT-Mod presented a cut-off of 1:100, satisfactory reproducibility (VC <5.8), sensitivity of 93.4%, specificity of 96.9%, and diagnostic efficiency of 95.5%. The improvement in antigen preparation reduced inter-batch variations and resulted in a high test performance.

PMID: 19457530 [PubMed - as supplied by publisher]

3: Trans R Soc Trop Med Hyg. 2009 Mar;103(3):291-7. Epub 2008 Dec 31.Click here to read LinkOut

Analysis of an acute Chagas disease outbreak in the Brazilian Amazon: human cases, triatomines, reservoir mammals and parasites.

Valente SA, da Costa Valente V, das Neves Pinto AY, de Jesus Barbosa César M, dos Santos MP, Miranda CO, Cuervo P, Fernandes O.

SVS - Instituto Evandro Chagas, Belém, PA, Brazil. aldovalente@iec.pa.gov.br

An outbreak of Chagas disease occurred in Mazagão, Amapá, Brazilian Amazon in 1996. Seventeen of 26 inhabitants presented symptoms compatible with acute Chagas disease and were submitted to parasitological and serological tests. All 17 were positive in at least one parasitological test and 11 were also IgM or IgG anti-Trypanosoma cruzi positive. The nine asymptomatic patients were negative for parasites and one was positive for IgG anti-T. cruzi. Sixty-eight triatomines were captured (66 Rhodnius pictipes; two Panstrongylus geniculatus); 45 were infected with T. cruzi (43 R. pictipes; two P. geniculatus). Thirteen trypanosomatid strains were isolated: eight from humans and five from R. pictipes. Four were genotyped as T. cruzi I (two from humans; two from R. pictipes), seven as T. cruzi Z3 (six from humans; one from R. pictipes) and two as T. cruzi Z3 and T. rangeli (from R. pictipes). Treatment started for all patients leading to a decrease in parasitaemia in 16 during the follow-up period (6 months, 1, 5 and 7 years). All were serologically negative 7 years post-treatment. There was an overlap of genotypes in the same ecotope, raising the possibility of transmission through the oral route and the need for early therapeutic intervention for better patient management in the Brazilian Amazon.

PMID: 19118852 [PubMed - indexed for MEDLINE]

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