Wednesday, December 21, 2011

What's new for 'Trypanosomatids' in PubMed

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Sent on Wednesday, 2011 December 21
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. RNA. 2011 Dec 19. [Epub ahead of print]

KREPB6, KREPB7, and KREPB8 are important for editing endonuclease function in Trypanosoma brucei.

Guo X, Carnes J, Ernst NL, Winkler M, Stuart K.

Source

Seattle Biomedical Research Institute, Seattle, Washington 98109, USA.

Abstract

Three distinct editosomes are required for the uridine insertion/deletion editing that creates translatable mitochondrial mRNAs in Trypanosoma brucei. They contain KREPB6, KREPB7, or KREPB8 proteins and their respective endonucleases KREN3, KREN2, or KREN1. RNAi knockdowns of KREPB6, KREPB7, and KREPB8 variably affect growth and RNA editing. KREPB6 and KREPB7 knockdowns substantially reduced in vitro insertion site cleavage activity of their respective editosomes, while KREPB8 knockdown did not affect its editosome deletion site cleavage activity despite inhibition of growth and editing. KREPB6, KREPB7, and KREPB8 knockdowns disrupted tagged KREN3, KREN2, or KREN1 editosomes, respectively, to varying degrees, and in the case of KREN1 editosomes, the deletion editing site cleavage activity shifted to a smaller S value. The varying effects correlate with a combination of the relative abundances of the KREPB6-8 proteins and of the different insertion and deletion sites. Tagged KREPB6-8 were physically associated with deletion subcomplexes upon knockdown of the centrally interactive KREPA3 protein, while KREN1-3 endonucleases were associated with insertion subcomplexes. The results indicate that KREPB6-8 occupy similar positions in editosomes and are important for the activity and specificity of their respective endonucleases. This suggests that they contribute to the accurate recognition of the numerous similar but diverse editing site substrates.

PMID:
22184461
[PubMed - as supplied by publisher]
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2. Rev Inst Med Trop Sao Paulo. 2011 Dec;53(6):329-34.

Potential utility of hyperbaric oxygen therapy and propolis in enhancing the leishmanicidal activity of glucantime.

Ayres DC, Fedele TA, Marcucci MC, Giorgio S.

Source

Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, Brasil, 13083-970.

Abstract

In this study we investigated the efficacy of hyperbaric oxygen (HBO) therapy, alone or combined with the pentavalent antimonial glucantime on Leishmania amazonensis infection. In parallel, the effect of Brazilian red propolis gel (propain) alone or combined with glucantime on L. amazonensis infection was evaluated. The inhibition of the infection in macrophages treated with glucantime in combination with HBO exposition was greater than that of macrophages treated with glucantime alone or HBO alone. The susceptible mouse strain BALB/c infected in the shaved rump with L. amazonensis treated with glucantime and exposed to HBO showed: time points in the course of the disease in which lesions were smaller than those of mice treated with glucantime alone and revascularization of the skin in the lesion site; interferon-gamma (IFN-g) levels were not elevated in lymph node cells from these animals. Propain alone was not efficient against lesions, although less exudative lesions were observed in animals treated with propain alone or combined with glucantime. These results reveal the potential value of HBO and red propolis in combination with glucantime for treating cutaneous leishmaniasis and encourage further studies on the effect of more aggressive HBO, propolis and glucantime therapies on different mouse models of leishmaniasis.

PMID:
22183457
[PubMed - in process]
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3. BMC Genomics. 2011 Dec 19;12(1):614. [Epub ahead of print]

PhosTryp: a phosphorylation site predictor specific for parasitic protozoa of the family trypanosomatidae.

Palmeri A, Gherardini PF, Tsigankov P, Ausiello G, Spath GF, Zilberstein D, Helmer-Citterich M.

Abstract

ABSTRACT:

BACKGROUND:

Protein phosphorylation modulates protein function in organisms at all levels of complexity. Parasites of the Leishmania genus undergo various developmental transitions in their life cycle triggered by changes in the environment. The molecular mechanisms that these organisms use to process and integrate these external cues are largely unknown. However Leishmania lacks transcription factors, therefore most regulatory processes may occur at a post-translational level and phosphorylation has recently been demonstrated to be an important player in this process. Experimental identification of phosphorylation sites is a time-consuming task. Moreover some sites could be missed due to the highly dynamic nature of this process or to difficulties in phospho-peptide enrichment.

RESULTS:

Here we present PhosTryp, a phosphorylation site predictor specific for trypansomatids. This method uses an SVM-based approach and has been trained with recent Leishmania phosphosproteomics data. PhosTryp achieved a 17% improvement in prediction performance compared with Netphos, a non organism-specific predictor. The analysis of the peptides correctly predicted by our method but missed by Netphos demonstrates that PhosTryp captures Leishmania-specific phosphorylation features. More specifically our results show that Leishmania kinases have sequence specificities which are different from their counterparts in higher eukaryotes. Consequently we were able to propose two possible Leishmania-specific phosphorylation motifs. We further demonstrate that this improvement in performance extends to the related trypanosomatids Trypanosoma brucei and Trypanosoma cruzi. Finally, in order to maximize the usefulness of PhosTryp, we trained a predictor combining all the peptides from L. infantum, T. brucei and T. cruzi.

CONCLUSIONS:

Our work demonstrates that training on organism-specific data results in an improvement that extends to related species. PhosTryp is freely available at http://phostryp.bio.uniroma2.it.

PMID:
22182631
[PubMed - as supplied by publisher]
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