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: Z Naturforsch C. 2009 Jul-Aug;64(7-8):509-12.

Bioactivity of flavonoids isolated from Lychnophora markgravii against Leishmania amazonensis amastigotes.

Salvador MJ, Sartori FT, Sacilotto AC, Pral EM, Alfieri SC, Vichnewski W.

Curso de Farmácia, Instituto de Biologia, Departamento de Biologia Vegetal, Universidade Estadual de Campinas (UNICAMP), Caixa Postal 6109, CEP 13083-970, Campinas (SP), Brazil. mjsalvador@bol.com.br

The bioactivity of the flavonoids pinostrobin (1), pinocembrin (2), tectochrysin (3), galangin 3-methyl ether (4), and tiliroside (5) isolated from Lychnophora markgravii aerial parts was investigated in vitro against amastigote stages of Leishmania amazonensis. The compounds were isolated by several chromatographic techniques and their chemical structures were established by ESI-MS and NMR spectroscopic data. The flavonoids 1 and 3 were the most active compounds; they markedly reduced the viability of Leishmania amastigotes.

PMID: 19791501 [PubMed - in process]

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  Zhongguo Zhong Yao Za Zhi. 1999 Mar; 24(3):162-4, 191.

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• Stage-specific glycosphingolipids from amastigote forms of Leishmania (L.) amazonensis. Immunogenicity and role in parasite binding and invasion of macrophages.

  J Biol Chem. 1993 Jun 25; 268(18):13723-30.

  [J Biol Chem. 1993]

• Role of Leishmania (Leishmania) amazonensis amastigote glycosphingolipids in macrophage infectivity.

  Braz J Med Biol Res. 2007 Jun; 40(6):799-806.

  [Braz J Med Biol Res. 2007]

• ReviewLife in vacuoles--nutrient acquisition by Leishmania amastigotes.

  Int J Parasitol. 2001 Oct; 31(12):1311-20.

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2: Curr Opin Microbiol. 2009 Aug;12(4):415-21. Epub 2009 Jul 17. LinkOut

Fighting the oxidative assault: the Trypanosoma cruzi journey to infection.

Piacenza L, Alvarez MN, Peluffo G, Radi R.

Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo-Uruguay, Uruguay.

Activation of professional phagocytes with the concomitant generation of oxidant species is a medullar innate immune process for the control of acute Trypanosoma cruzi infection. Recent data reinforce the hypothesis that parasites more prepared to deal with the host-oxidative assault are more efficient for the establishment of Chagas disease. For instance, parasites overexpressing peroxiredoxins are more resistant to macrophage-derived peroxynitrite, a key cytotoxic oxidant produced in the phagosome towards the internalized parasite. Differentiation to the infective metacyclic trypomastigote is accompanied by an increased expression of antioxidant enzymes. Moreover, augmented antioxidant enzyme expression and activities correlate with higher parasite virulence in experimental infections. The potency of the parasite antioxidant armamentarium influences the final fate of the Trypanosoma cruzi journey to macrophage invasion at the onset of infection.

PMID: 19616990 [PubMed - indexed for MEDLINE]

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• Peroxiredoxins play a major role in protecting Trypanosoma cruzi against macrophage- and endogenously-derived peroxynitrite.

  Biochem J. 2008 Mar 1; 410(2):359-68.

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• Host and parasite factors affecting the invasion of mononuclear phagocytes by Trypanosoma cruzi.

  Ciba Found Symp. 1983; 99:52-73.

  [Ciba Found Symp. 1983]

• ReviewTrypanosoma cruzi recognition by macrophages and muscle cells: perspectives after a 15-year study.

  Mem Inst Oswaldo Cruz. 1992; 87 Suppl 5:43-56.

  [Mem Inst Oswaldo Cruz. 1992]

• Frequency distribution of Trypanosoma cruzi in macrophages from resistant and susceptible strains of mice.

  Experientia. 1980 Aug 15; 36(8):942-4.

  [Experientia. 1980]

• ReviewTrypanosoma cruzi infection by oral route: how the interplay between parasite and host components modulates infectivity.

  Parasitol Int. 2008 Jun; 57(2):105-9. Epub 2007 Dec 23.

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3: Acta Crystallogr D Biol Crystallogr. 2009 Jul;65(Pt 7):704-16. Epub 2009 Jun 20. Taxonomy via GenBank, Protein, Structure, 3D Domains, LinkOut

Structures of dihydrofolate reductase-thymidylate synthase of Trypanosoma cruzi in the folate-free state and in complex with two antifolate drugs, trimetrexate and methotrexate.

Senkovich O, Schormann N, Chattopadhyay D.

Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, USA.

The flagellate protozoan parasite Trypanosoma cruzi is the pathogenic agent of Chagas disease (also called American trypanosomiasis), which causes approximately 50,000 deaths annually. The disease is endemic in South and Central America. The parasite is usually transmitted by a blood-feeding insect vector, but can also be transmitted via blood transfusion. In the chronic form, Chagas disease causes severe damage to the heart and other organs. There is no satisfactory treatment for chronic Chagas disease and no vaccine is available. There is an urgent need for the development of chemotherapeutic agents for the treatment of T. cruzi infection and therefore for the identification of potential drug targets. The dihydrofolate reductase activity of T. cruzi, which is expressed as part of a bifunctional enzyme, dihydrofolate reductase-thymidylate synthase (DHFR-TS), is a potential target for drug development. In order to gain a detailed understanding of the structure-function relationship of T. cruzi DHFR, the three-dimensional structure of this protein in complex with various ligands is being studied. Here, the crystal structures of T. cruzi DHFR-TS with three different compositions of the DHFR domain are reported: the folate-free state, the complex with the lipophilic antifolate trimetrexate (TMQ) and the complex with the classical antifolate methotrexate (MTX). These structures reveal that the enzyme is a homodimer with substantial interactions between the two TS domains of neighboring subunits. In contrast to the enzymes from Cryptosporidium hominis and Plasmodium falciparum, the DHFR and TS active sites of T. cruzi lie on the same side of the monomer. As in other parasitic DHFR-TS proteins, the N-terminal extension of the T. cruzi enzyme is involved in extensive interactions between the two domains. The DHFR active site of the T. cruzi enzyme shows subtle differences compared with its human counterpart. These differences may be exploited for the development of antifolate-based therapeutic agents for the treatment of T. cruzi infection.

PMID: 19564691 [PubMed - indexed for MEDLINE]

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• Probing the role of parasite-specific, distant structural regions on communication and catalysis in the bifunctional thymidylate synthase-dihydrofolate reductase from Plasmodium falciparum.

  Biochemistry. 2008 Feb 5; 47(5):1336-45. Epub 2008 Jan 12.

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• Disruption of the crossover helix impairs dihydrofolate reductase activity in the bifunctional enzyme TS-DHFR from Cryptosporidium hominis.

  Biochem J. 2009 Feb 1; 417(3):757-64.

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• Lipophilic antifolate trimetrexate is a potent inhibitor of Trypanosoma cruzi: prospect for chemotherapy of Chagas' disease.

  Antimicrob Agents Chemother. 2005 Aug; 49(8):3234-8.

  [Antimicrob Agents Chemother. 2005]

• ReviewMalarial (Plasmodium falciparum) dihydrofolate reductase-thymidylate synthase: structural basis for antifolate resistance and development of effective inhibitors.

  Parasitology. 2005 Mar; 130(Pt 3):249-59.

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• ReviewThymidylate synthase-dihydrofolate reductase in protozoa.

  Exp Parasitol. 1990 Apr; 70(3):367-71.

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Structures reported by this article

• 
  Structures Of Dihydrofolate Reductase-Thymidylate Synthase Of Trypanosoma Cruzi In The Folate-Free State And In Complex With Two Antifolate Drugs, Trimetrexate And Methotrexate

  PDB: 3HBB

  Source: Trypanosoma cruzi

  Method: X-Ray Diffraction | Resolution: 3 Å

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  Methotrexate is used to treat severe psoriasis (a skin disease in which red, scaly patches form on some areas of the body) that cannot be controlled by other treatments. Methotrexate is also used along with rest, physica...

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4: Parasitol Int. 2009 Sep;58(3):215-9. Epub 2009 Jun 6. LinkOut

The composition of untranslated regions in Trypanosoma cruzi genes.

Brandão A, Jiang T.

Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil. abrandao@fiocruz.br

We collected the UTRs from Trypanosomacruzi genes that have been experimentally mapped and are publicly available, and made a comprehensive analysis of their composition features including sequence length, G+C content and relationship to ORF, composition of the most frequent words, and distribution of Simple Sequence Repeats (SSR). T. cruzi UTRs exhibit range length of 10-400bp for 5' UTR and 17-2800 for 3' UTR. Both UTRs display mean G+C content of 40%. Ratios between the UTR and protein coding segments show that the 5' UTR is limited to a maximum of 20% of the total length in the final transcript. The 5' UTR most frequent words in the range 4-12 bases are almost exact complement to the 3' UTR respective words. SSR in 3' UTR are longer than in 5' UTR and are mostly derived from TA/AT, TG/GT, and TTA/ATT. SSR accounts up to 20% of the nucleotide composition in 5' UTR and up to 90% in the 3' UTR.

PMID: 19505588 [PubMed - indexed for MEDLINE]

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5: FEMS Microbiol Lett. 2009 Jun;295(2):274-80. Epub 2009 May 1. LinkOut

Sialoglycoconjugates in Herpetomonas megaseliae: role in the adhesion to insect host epithelial cells.

Silva BA, Pereira FM, de Jesus JB, Branquinha MH, Santos AL, d'Avila-Levy CM.

Departamento de Microbiologia Geral, Centro de Ciências da Saúde, Instituto de Microbiologia Prof. Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.

Herpetomonas megaseliae is a monoxenic trypanosomatid isolated from the phorid fly Megaselia scalaris. In the present report, the expression of cell surface sialoglycoconjugates in this parasite was analyzed by Western blotting, flow cytometry and fluorescence microscopy analyses using lectins that specifically recognize sialic acid residues. A strong reaction was detected when parasites were treated with Limax flavus, Maackia amurensis and Sambucus nigra lectins. Analysis of crude protein extracts by Western blotting revealed that bands with molecular masses ranging from 19 to 80 kDa were reactive to these lectins, which showed a sugar-inhibited recognition with the parasite extract. These results indicated that molecules containing alpha2,3- and alpha2,6-sialylgalactosyl sequences are present in this protozoan. The role of the surface sialomolecules in the interaction with explanted guts from Aedes aegypti was assessed. The interaction of H. megaseliae with the insect gut was strongly inhibited in the presence of mucin (71%), fetuin (68%) and sialyllactose (68%). Collectively, our results suggest a possible involvement of sialomolecules in the interaction between this insect trypanosomatid and the invertebrate host.

PMID: 19459976 [PubMed - indexed for MEDLINE]

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