PARTIAL BIOCHEMICAL-CHARACTERIZATION OF 5 PARACOCCIDIOIDES-BRASILIENSIS STRAINS

The yeast forms of four strains of Paracoccidioides brasiliensis (SN, 2, 18, and 192), maintained in the laboratory for a long period of tim e, and a recent isolate of this fungus (JT-1) were cultured in a synth etic medium. Cell masses of each strain, in exponential growth phase, were obtained and lyophilized for partial analysis of their biochemica l 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 The material withdrawn during the purif ication phase (''supernatant of lipid purification'') was subjected to protein and carbohydrate measurements. Another subfraction, lipid-fre e yeast, was analyzed after cell rupture by sonication, in relation to protein and carbohydrate total contents. The results showed significa nt differences in the measurements of total lipids (6.6-13.2 mg%), pho spholipids (0.19-0.77 mg%) and glycolipids (0.14-0.42 mg%) among the f ive strains. Sterol analysis revealed the presence of ergosterol, lano sterol, and squalene in all of the samples. The measurements carried o ut on the supernatants of lipid purification and in the lipid-free yea sts also showed differences among the studied strains, particularly in relation to total carbohydrate content, which was significantly highe r in the recent isolate of the fungus (JT-1). As a whole, this study r evealed the existence of relevant biochemical differences among these different Paracoccidioides brasiliensis strains.