Extracellular release byTrichomonas vaginalisof a NADP+dependent malic enzyme involved in pathogenicity
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- 作者：Addis ; Maria Filippa ; Rappelli ; Paola ; Cappuccinelli ; Piero ; Fiori ; Pier Luigi
- 刊名：Microbial Pathogenesis
- 出版年：1997
- 出版时间：July, 1997
- 年：1997
- 卷：23
- 期：1
- 页码：55-61
- 全文大小：593 K
文摘
This report presents evidence showing thatTrichomonas vaginalisreleases in the extracellular environment a functional form of NADP+-dependent malic enzyme. The protein which is likely responsible for the oxidative decarboxilase activity had already been identified in previous studies as P65, one of the five adhesive proteins of the protozoan. The same protein had also been described as AP65 by other authors, which identified it as one of the four surface proteins specifically responsible for binding of the parasite to the target cell in a ligand-receptor fashion. Gene characterization studies performed on P65 by different authors revealed that the nucleotide sequences of the genes coding for P65 display a striking homology with the ones coding for the trichomonad malic enzyme. The experiments performed in this work demonstrate that P65 is secreted and retains its adhesive properties in the extracellular environment, being able to bind both erythrocytes and HeLa cells. Therefore, an oxidative decarboxylase activity assay was performed onT. vaginaliscell-free filtrates, in order to assess if the released P65 displays cathalitic properties. The assay revealed that parasite-free supernatants exhibit an oxidative decarboxylase activity which is NADP+-dependent. On the basis of the most recent findings onT. vaginalispathogenetic mechanism, which involves pH-dependent perforins, a role for the secreted enzyme as part of the system is proposed.