Characterization of an ecto-phosphatase activity in the human parasite Trichomonas vaginalis

Jesus, José Batista de; Podlyska, T. M.; Hampshire, A.; Lopes, Carolina; Vannier-Santos, Marcos A.; Meyer‐Fernandes, José Roberto

doi:10.1007/s00436-001-0583-2

Cited by 28 publications

(15 citation statements)

References 38 publications

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“…The inhibition by zinc chloride (Figs. 4 and 5) supports the hypothesis that ecto-phosphatase is related to the phosphotyrosine phosphatase family, together with other ecto-phosphatases (Fernandes et al, 1997;Furuya et al, 1998;Meyer-Fernandes et al, 1999;Jesus et al, 2002).…”

Section: September 2004supporting

confidence: 78%

“…Trypanosoma cruzi (Furuya et al, 1998), Herpetomonas muscarum muscarum (Dutra et al, 1998), Trichomonas vaginalis (Jesus et al, 2002), Leishmania donovani (Gottlieb and Dwyer, 1981), and others. The physiological role of the membrane-bound acid phosphatase has not been well established, although in protozoan they are through to be involved in nutrition and protection (Gottlieb and Dwyer, 1981), virulence (Furuya et al, 1998), and cell differentiation (Meyer-Fernandes et al, 1999).…”

Section: September 2004mentioning

confidence: 99%

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Characterization of an ecto‐phosphatase activity in malpighian tubules of hematophagous bug Rhodnius prolixus

Ferraro

Sousa

Cunha

et al. 2004

Arch Insect Biochem Physiol

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We have characterized a phosphatase activity present on the external surface of intact Malpighian tubules in Rhodnius prolixus. This phosphatase hydrolyses the substrate p-nitrophenyl phosphate at a rate of 3.38 +/- 0.07 nmol Pi x mg(-1) x min(-1). Phosphatase activity decreased with the increase of the pH from 6.4 to 7.6 pH, a range in which tubules cellular integrity was maintained for at least 1 h. Classical inhibitors of acid phosphatase, such as ammonium molybdate, fluoride, vanadate, mpV-PIC, and bpV-PHEN, caused different patters of inhibition. The ecto-phosphatase present an apparent Km of 1.67 +/- 0.34 mM and Vmax of 5.71 +/- 0.37 nmol Pi x mg(-1) x min(-1) for p-NPP. Zinc chloride inhibited 78.2% of ecto-phosphatase activity, with Ki of 0.35 mM. Such inhibition was reversed by incubation with cysteine and GSH, but not DTT, serine, and GSSG, showing that cysteine residues are important for enzymatic activity. Phosphatase activity increased 141% three days after blood meal, and returned to basal levels 2 days later. These results suggest that ecto-phosphatase activity could be involved in a diuretic mechanism, essential in the initial days after a blood meal for the control of Rhodnius homeostasis.

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Section: September 2004supporting

confidence: 78%

Section: September 2004mentioning

confidence: 99%

Characterization of an ecto‐phosphatase activity in malpighian tubules of hematophagous bug Rhodnius prolixus

Ferraro

Sousa

Cunha

et al. 2004

Arch Insect Biochem Physiol

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“…However, the involvement of a parasite cytotoxic contact-independent mechanism deserves further consideration since some parasite hydrolases with cytotoxic potential are released by T. vaginalis (Alderete and Garza 1985;Arroyo and Alderete 1989;Jesus et al 2002).…”

Section: Introductionmentioning

confidence: 98%

Trichomonas vaginalis virulence against epithelial cells and morphological variability: the comparison between a well-established strain and a fresh isolate

et al. 2004

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The FMVI strain of Trichomonas vaginalis was freshly isolated from an asymptomatic patient, and its morphological properties and virulence in vitro compared with the well-established JT strain. The morphological variability of the parasites was assessed by differential interference microscopy and both scanning and transmission electron microscopy. The FMV1 strain presented nearly 20% amoeboid cells whereas the JT strain presented high percentages of ellipsoid but no amoeboid cells. The FMV1 morphotype population was unaltered after at least 1 year of subculturing. Electron microscopy revealed that this strain produced numerous pseudopod structures which mediated intimate contact and interdigitation among trophozoites. Dead FMV1 parasites were often phagocytosed by conspecific cells. We also compared the cytolytic capacity of these two populations against epithelial MDCK cells and its contact dependence. The FMV1 strain rapidly adhered to plastic or glass surfaces and to MDCK monolayers. This strain destroyed about 93% of the epithelial cells in 90 min whereas the cytolytic activity of the JT parasites was very much lower (about 41%). Parasite supernatants displayed no cytolytic activity, indicating contact-mediated lysis. The protozoan virulence in vitro did not correlate well with the clinical observations. The implications of these results are discussed.

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“…Table 1 shows that both nucleotidase activities were insensitive to oligomycin and sodium azide, two inhibitors of mitochondrial Mg-ATPase (Meyer-Fernandes et al, 1997); bafilomycin A 1 , a V-ATPase inhibitor (Browman et al, 1988); ouabain, a Na + K + -ATPase inhibitor (Caruso-Neves et al, 1998), and vanadate, a potent inhibitor of PATPases and acid phosphatases (Sodre et al, 2000;Dutra et al, 2001;De Jesus et al, 2002). Molybdate and sodium fluoride, two potent inhibitors of acid phosphatase activity (Meyer-Fernandes et al, 1999), did not inhibit either ecto-nucleotidase activity (Table 1).…”

Section: Resultsmentioning

confidence: 99%

Ecto-nucleotidase activities in the fat body ofRhodnius prolixus

Entringer

Gondim

Meyer‐Fernandes

2005

Arch. Insect Biochem. Physiol.

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In this study, we describe the ability of intact fat body of an insect, Rhodnius prolixus, to hydrolyze extracellular ATP. In these fat bodies, the ATP hydrolysis was low in the absence of any divalent metal, and was stimulated by MgCl 2 . Both activities (in the absence or presence of MgCl 2 ) were linear with time for at least 30 min. In order to confirm the observed nucleotidase activities as ecto-nucleotidases, we used an impermeant inhibitor, DIDS (4, 4′-diisothiocyanostylbene 2′-2′-disulfonic acid). This reagent inhibited both nucleotidase activities and its inhibitory effect was suppressed by ATP. Both ecto-nucleotidase activities were insensitive to inhibitors of other ATPase and phosphatase activities, such as oligomycin, sodium azide, bafilomycin, ouabain, vanadate, molybdate, sodium fluoride, levamizole, tartrate, p-NPP, sodium phosphate, and suramin. Concanavalin A, activator of some ecto-ATPases, was able to stimulate the Mg 2+ -independent nucleotidase activity, but not the Mg 2+ -dependent one. The Mg 2+ -independent nucleotidase activity was enhanced with increases in the pH in the range between 6.4-8.0, but the Mg 2+ -dependent nucleotidase activity was not affected. Besides MgCl 2 , the ecto-ATPase activity was also stimulated by CaCl 2 , MnCl 2 , and SrCl 2 , but not by ZnCl 2 . ATP, ADP, and AMP were the best substrates for the Mg 2+ -dependent ecto-nucleotidase activity, and CTP, GTP, and UTP produced very low reaction rates. However, the Mg 2+ -independent nucleotidase activity recognized all these nucleotides producing similar reaction rates, but GTP was a less efficient substrate. The possible role of the two ecto-nucleotidase activities present on the cell surface of fat body of Rhodnius prolixus, which are distinguished by their substrate specificity and their response to Mg 2+ , is discussed. Arch. Insect Biochem. Physiol. 61:1-9, 2006.

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Characterization of an ecto-phosphatase activity in the human parasite Trichomonas vaginalis

Cited by 28 publications

References 38 publications

Characterization of an ecto‐phosphatase activity in malpighian tubules of hematophagous bug Rhodnius prolixus

Characterization of an ecto‐phosphatase activity in malpighian tubules of hematophagous bug Rhodnius prolixus

Trichomonas vaginalis virulence against epithelial cells and morphological variability: the comparison between a well-established strain and a fresh isolate

Ecto-nucleotidase activities in the fat body ofRhodnius prolixus

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