Partial biochemical characterization of fiveParacoccidioides brasiliensis strains

Abstract

The yeast forms of four strains ofParacoccidioides brasiliensis (SN, 2, 18, and 192), maintained in the laboratory for a long period of time, and a recent isolate of this fungus (JT-1) were cultured in a synthetic medium. Cell masses of each strain, in exponential growth phase, were obtained and lyophilized for partial analysis of their biochemical composition. The lipids of the five strains were extracted, purified, and analyzed in relation to the presence of sterols, phospholipids, glycolipids, and lipoproteins. The material withdrawn during the purification phase (“supernatant of lipid purification”) was subjected to protein and carbohydrate measurements. Another subfraction, lipid-free yeast, was analyzed after cell rupture by sonication, in relation to protein and carbohydrate total contents. The results showed significant differences in the measurements of total lipids (6.6–13.2 mg%), phospholipids (0.19–0.77 mg%) and glycolipids (0.14–0.42 mg%) among the five strains. Sterol analysis revealed the presence of ergosterol, lanosterol, and squalene in all of the samples. The measurements carried out on the supernatants of lipid purification and in the lipid-free yeasts also showed differences among the studied strains, particularly in relation to total carbohydrate content, which was significantly higher in the recent isolate of the fungus (JT-1). As a whole, this study revealed the existence of relevant biochemical differences among these differentParacoccidioides brasiliensis strains.