Kinetic characterization and gene expression of adenosine deaminase in intact trophozoites of Trichomonas vaginalis

Authors

  • Marina Weizenmann,

    1. Laboratório de Pesquisa em Parasitologia, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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  • Amanda Piccoli Frasson,

    1. Laboratório de Pesquisa em Parasitologia, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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  • Muriel Primon de Barros,

    1. Laboratório de Pesquisa em Parasitologia, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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  • Patrícia de Brum Vieira,

    1. Laboratório de Pesquisa em Parasitologia, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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  • Denis Broock Rosemberg,

    1. Departamento de Bioquímica, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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  • Geraldo Attilio De Carli,

    1. Instituto de Geriatria e Gerontologia, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
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  • Maurício Reis Bogo,

    1. Laboratório de Biologia Genômica e Molecular, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
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  • Carla Denise Bonan,

    1. Laboratório de Neuroquímica e Psicofarmacologia, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
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  • Tiana Tasca

    1. Laboratório de Pesquisa em Parasitologia, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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  • Editor: Albert Descoteaux

Correspondence: Tiana Tasca, Laboratório de Pesquisa em Parasitologia, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Av. Ipiranga 2752, 90610-000, Porto Alegre, RS, Brazil. Tel.: +55 51 3308 5325; fax: +55 51 3308 5437; e-mail: tiana.tasca@ufrgs.br

Abstract

Trichomonas vaginalis is a parasite that resides in the human urogenital tract and causes trichomonosis, the most prevalent nonviral sexually transmitted disease. Nucleoside triphosphate diphosphohydrolase (NTPDase), which hydrolyzes extracellular di- and triphosphate nucleotides, and ecto-5′-nucleotidase, which hydrolyzes AMP, have been characterized in T. vaginalis. The aim of this study was to characterize the adenosine deaminase (ADA) activity in intact trophozoites of T. vaginalis. A strong inhibition in adenosine deamination was observed in the presence of calcium and magnesium, which was prevented by EDTA. The apparent KM value for adenosine was 1.13 ± 0.07 mM. The calculated Vmax was 2.61 ± 0.054 nmol NH3 min−1 mg−1 protein. Adenosine deamination was inhibited in the presence of erythro-9-(2-hydroxy-3-nonyl)adenine. Semi-quantitative reverse transcriptase-PCR experiments were performed and both ADA-related genes ada(125) and ada(231) mRNA were expressed, although ada(231) in higher quantity when compared with the ada(125) : α-tubulin ratio. Furthermore, a phylogenetic analysis showed that the T. vaginalis sequences formed a clade with Entamoeba histolytica and Dictyostelium discoideum sequences, and it strongly suggests homologous functions in the T. vaginalis genome. The presence of ADA activity in T. vaginalis may be important to modulate the adenosine/inosine levels during infection and, consequently, to maintain the anti-inflammatory properties through different nucleoside-signalling mechanisms.

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