RESUMEN
Yeast cells of Paracoccidioides brasiliensis strain SN, were obtained for analysis of lipid composition. Total lipids, phospholipids, sterols, and qualitative sterols and fatty acid composition were determined. Such analysis were made on cells cultured in the presence or absence of amphotericin B and on non proliferating cell suspensions exposed to the antibiotic. Marked alterations in lipid contents were observed in this different conditions. The major alterations were the reduction of total lipids, sterols, and palmitoleic acid in both, proliferating and non proliferating antibiotic exposed cells. The effect of amphotericin B was evaluated also in terms of viability and release of intracellular substances, at different times of exposure. The minimal inhibitory concentration (MIC) determined for that strain of this fungus was 0.2 microgram/mL.
Asunto(s)
Anfotericina B/farmacología , Lípidos/análisis , Hongos Mitospóricos/análisis , Paracoccidioides/análisis , Ácidos Grasos/análisis , Fosfolípidos/análisis , Potasio/metabolismo , Esteroles/análisisRESUMEN
We carried out a comparative study of the histopathology (lung, liver, spleen, kidney and adrenals) and the anti-P. brasiliensis humoral (immunodiffusion test) and cellular (footpad test) immune response of mice intravenously inoculated with yeast forms of three P. brasiliensis isolates (Pb 18, Pb 192, Pb 265). Pb 265 (avirulent strain) did not evoke specific lesions or antibody production; the levels of cellular immunity were significantly lower than those of the two other isolates. Lung granulomas induced by strain Pb 18 were richer in fungi and neutrophils and poorer in mononuclear cells when compared to those induced by strain Pb 192. Extrapulmonary lesions were more frequent in mice infected with strain Pb 18. Strains Pb 18 and Pb 192 raised similar humoral and cellular anti-P. brasiliensis responses. Cell wall analysis did not suggest striking differences among the strains. Slightly higher levels of the water soluble fraction 3 (which contains the immunogenic galactomannan and protein) were detected in strain Pb 265.
Asunto(s)
Hongos Mitospóricos/análisis , Paracoccidioides/análisis , Paracoccidioidomicosis/patología , Animales , Anticuerpos Antifúngicos/biosíntesis , Pared Celular/análisis , Inmunidad Celular , Masculino , Ratones , Paracoccidioides/inmunología , Paracoccidioides/ultraestructura , Paracoccidioidomicosis/inmunología , Paracoccidioidomicosis/microbiologíaRESUMEN
The occurrence of a polysaccharide fraction of Paracoccidioides brasiliensis cell wall with toxic, granuloma-inducing and macrophage-stimulating activities was demonstrated. After fractionation of the lipid-extracted wall with 1 M-NaOH, three fractions were obtained: (1) an alkali-insoluble fraction; (2) an alkali-soluble, acid-insoluble fraction and (3) an alkali-soluble, acid-soluble fraction. When the three fractions were injected into mice only fraction (1) was able to induce chronic lung inflammation, causing a marked loss in body weight and death at a dose of 6 mg per animal. Analysis of the stimulation of peritoneal macrophages of mice (measured by cell spreading on glass) after intraperitoneal injection of fraction 1 showed that 75% of the cells were able to spread even 20 d after inoculation.