title: Platelet-activating factor modulates a secreted phosphatase activity of the trypanosomatid parasite Herpetomonas muscarum muscarum.
abstract: In the present work we characterized the secreted phosphatase activity of the trypanosomatid parasite Herpetomonas muscarum muscarum. This housefly parasite hydrolyzed p-nitrophenylphosphate at a rate of 10.26 nmol Pi/mg protein/min. Classical inhibitors of acid phosphatases, such as sodium orthovanadate (NaVO3), sodium fluoride (NaF), and ammonium molybdate promoted a decrease in this phosphatase activity. When the parasites were assayed in the presence of sodium tartrate, an inhibitor of Leishmania spp-secreted acid phosphatases, this activity was drastically diminished. Cytochemical analysis showed the localization of this enzyme on the external surface and in the flagellar pocket of these parasites. Sodium tartrate inhibited this reaction, confirming the biochemical data. Platelet-activating factor (PAF) inhibited the phosphatase activity determined in the supernatant of living H. m. muscarum.
authors.affiliation: Instituto de Microbiologia Professor Paulo de Góes, UFRJ, Ilha do Fundão, Rio de Janeiro, RJ, Brazil.
authors.forename: P M
authors.initials: PM
authors.lastname: Dutra
authors.forename: F A
authors.initials: FA
authors.lastname: Dias
authors.forename: C O
authors.initials: CO
authors.lastname: Rodrigues
authors.forename: A
authors.initials: A
authors.lastname: Romeiro
authors.forename: M
authors.initials: M
authors.lastname: Attias
authors.forename: W
authors.initials: W
authors.lastname: De Souza
authors.forename: A H
authors.initials: AH
authors.lastname: Lopes
authors.forename: J R
authors.initials: JR
authors.lastname: Meyer-Fernandes
mesh_terms: D000135:Acid Phosphatase / Q000187:drug effects* / Q000378:metabolism*; D000818:Animals; D003470:Culture Media; D006793:Houseflies / Q000469:parasitology*; D010972:Platelet Activating Factor / Q000494:pharmacology*; D014351:Trypanosomatina / Q000201:enzymology* / Q000254:growth & development
chemical_list: D003470:Culture Media; D010972:Platelet Activating Factor; D000135:Acid Phosphatase