Phosphatase activity on the cell wall of Fonsecaea pedrosoi

Phosphatase activity on the cell wall of Fonsecaea pedrosoi

Author Kneipp, L. F. Google Scholar
Palmeira, V. F. Google Scholar
Pinheiro, AAS Google Scholar
Alviano, C. S. Google Scholar
Rozental, S. Google Scholar
Travassos, L. R. Google Scholar
Meyer-Fernandes, JR Google Scholar
Institution Universidade Federal do Rio de Janeiro (UFRJ)
Universidade Federal de São Paulo (UNIFESP)
Abstract The activity of a phosphatase was characterized in intact mycelial forms of Fonsecaea pedrosoi, a pathogenic fungus that causes chromoblastomycosis. At pH 5.5, this fungus hydrolyzed p-nitrophenylphosphate (p-NPP) to p-nitrophenol (p-NP) at a rate of 12.78 +/- 0.53 nmol p-NP per h per mg hyphal dry weight. the values of V-max and apparent K-m for p-NPP hydrolyses were measured as 17.89 +/- 0.92 nmol p-NP per h per mg hyphal dry weight and 1.57 +/- 0.26 mmol/l, respectively. This activity was inhibited at increased pH, a finding compatible with an acid phosphatase. the enzymatic activity was strongly inhibited by classical inhibitors of acid phosphatases such as sodium orthovanadate (K-i = 4.23 mumol/l), sodium molybdate (K-i = 7.53 mumol/l) and sodium fluoride (K-i = 126.78 mumol/l) in a dose-dependent manner. Levamizole (1 mmol/l) and sodium tartrate (10 mmol/l), had no effect on the enzyme activity. Cytochemical localization of the acid phosphatase showed electrondense cerium phosphate deposits on the cell wall, as visualized by transmission electron microscopy. Phosphatase activity in F pedrosoi seems to be associated with parasitism, as sclerotic cells, which are the fungal forms mainly detected in chromoblastomycosis lesions, showed much higher activities than conidia and mycelia did. A strain of F pedrosoi recently isolated from a human case of chromoblastomycosis also showed increased enzyme activity, suggesting that the expression of surface phosphatases may be stimulated by interaction with the host.
Keywords chromoblastomycosis
Fonsecaea pedrosoi
phosphatase activity
Language English
Date 2003-12-01
Published in Medical Mycology. Abingdon: Taylor & Francis Ltd, v. 41, n. 6, p. 469-477, 2003.
ISSN 1369-3786 (Sherpa/Romeo, impact factor)
Publisher Taylor & Francis Ltd
Extent 469-477
Access rights Closed access
Type Article
Web of Science ID WOS:000188043500002

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