Acid Phosphatases of Sporothrix schenckii

Abstract

Sporothrix schenckii cells were grown on a medium containing yeast extract, neopeptone and glucose at 20 "C to obtain a mixture of mycelia and conidia, and at 35 "C to obtain yeast-like cells. The organism was maintained in the mycelial form, and its transformation to yeast at the higher temperature proceeded via conidia and 'intermediate cells' that then gave rise to yeast by a blastic mechanism. Cell-free extracts were analysed by PAGE at pH 8.0 and acid phosphatases (EC 3.1.3.2) were revealed by a sensitive detection reagent at pH 5.0. Mycelial, conidial and yeast extracts all had some acid phosphatase activity (M-I, C-I and Y-I) at the origin, although the proportion was highest for the yeast extracts. All of the bands that penetrated the gels had different electrophoretic mobilities. Mycelial and conidial extracts each had one other isoenzyme (M-I1 and C-11), while the yeast extracts had a total of five electrophoretically distinct acid phosphatases. Isoenzyme Y-I1 was further resolved into five closely related bands (Y-IIa to Y-He), the relative intensities of which varied with the phosphate nutrition of the yeast cells and the history of the extracts. The acid phosphatase isoenzymes were inhibited to various extents by sodium fluoride, L( +)-tartrate and phosphate, and showed interactions with citrate as opposed to acetate as the background buffer at pH 5.0.

Selective Inactivation of an Extra-cytoplasmic Acid Phosphatase of Yeast-like Cells of Sporothrix schenckii by Sodium Fluoride

“…Mechanical disruption of S. schenckii yeast cells results in an increase in acid phosphatase activity of 50-75% (Arnold et al, 1986; this paper); the increment is due to the exposure of the cytoplasmic enzymes to substrate and can be equated with vacuolar and internal membrane sites (Garrison & Arnold, 1983).…”

“…Gels were subsequently washed in cold buffer followed by 7% (v/v) acetic acid and stored in the cold. All of the above methods were described in detail by Arnold et al (1986).…”

“…We have reported (Arnold et al, 1986) that the nine isoenzymes of acid phosphatase in yeast cells of S. schenckii are inhibited to varying degrees by fluoride, L(+)-tartrate and orthophosphate. In cytochemical studies with glutaraldehyde-fixed (and concomitantly permeabilized) cells, the addition of NaF to control incubations with a modified Gomori (1950) reagent obliterated all the sites of acid phosphatase activity (Garrison & Arnold, 1983).…”

“…2 ) activity (Garrison & Arnold, 1983). The acid phosphatases are ubiquitous among yeast and yeastlike organisms (Arnold, 1981), but they are of special interest with S. schenckii because of differences in the isoenzyme patterns among cells of the saprophytic and pathogenic forms (Arnold et al, 1986).…”

Ectophosphatase activity in conidial forms of Fonsecaea pedrosoi is modulated by exogenous phosphate and influences fungal adhesion to mammalian cells

“…The presence of surface-located acid phosphatases, called ecto-or extracytoplasmic phosphatases, has been reported in many micro-organisms (Fernandes et al, 1997;Dutra et al, 1998;Meyer-Fernandes et al, 1999;Braibant & Content, 2001), including the fungi Saccharomyces cerevisiae (Mildner et al, 1975), Candida parapsilosis (Fernando et al, 1999), Sporothrix schenckii (Arnold et al, 1986) and Aspergillus fumigatus (Bernard et al, 2002). The specific functions of these enzymes are not fully known, but they probably participate in cell wall biosynthesis in yeast cells (Novick et al, 1981).…”