RESUMEN
Penicillium janczewskii, a filamentous fungus isolated from the rhizosphere of Vernonia herbacea (Asteraceae), grows rapidly on media containing either sucrose or inulin as carbon sources. Maintenance of P. janczewskii on inulin medium induces secretion of proteins with high inulinase activity but results in a mycelium that easily collapses and breaks. We evaluated the influence of inulin on fungal growth and colony morphology and on cell-wall structure and composition in comparison with growth and wall characteristics on sucrose-containing medium. P. janczewskii grown on Czapek medium with agar containing 1% (w/v) sucrose or inulin showed differences in the color and morphology of the colonies, although growth rates were similar on both carbon sources. Scanning-electron microscopy revealed that the hyphae from fungus grown on inulin-containing medium are much thinner than those from fungus cultivated on sucrose. Ultrastructural analysis of 5 d old cultures using transmission-electron microscopy indicated significant differences in the cell-wall thickness between hyphae grown on inulin or sucrose media. No differences were detected in the overall carbohydrate and protein contents of cell walls isolated from cultures grown on the two carbon sources. Glycosyl composition analyses showed glucose and galactose as the predominant neutral monosaccharides in the walls but showed no differences attributable to the carbon source. Glycosyl linkage composition analyses indicated a predominance of 3-linked glucopyranosyl in the hyphal walls when P. janczewskii was grown on inulin-containing medium. Our results suggest that growth on inulin as the sole carbon source results in structural changes in the mycelia of P. janczewskii that lead to mycelial walls with altered physical and biological properties.
Asunto(s)
Pared Celular/química , Pared Celular/ultraestructura , Inulina/metabolismo , Penicillium/química , Carbohidratos/análisis , Proteínas Fúngicas/análisis , Hifa/ultraestructura , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Penicillium/crecimiento & desarrollo , Penicillium/ultraestructura , Sacarosa/metabolismoRESUMEN
Penicillium janczewskii Zaleski is an efficient microorganism for the production of extracellular inulinases and grows rapidly on medium containing sucrose or inulin as carbon source. Maintenance of this filamentous fungus on inulin medium induces secretion of large amounts of inulinases, but the resulting mycelium has thinner cell walls that easily collapse and break. Woronin bodies in hyphae of P. janczewskii grown on sucrose and inulin substrates were observed. No significant differences in the number, location, size and shape of Woronin bodies and level of plugging were observed in cultures of the fungus grown on the two carbon sources. The data indicate that the presence of Woronin bodies in P. janczewskii could not be associated with more easily damaged hyphae, although the function of these organelles in pore plugging has been confirmed.
Asunto(s)
Hongos , Técnicas In Vitro , Inulina , Penicillium , Sacarosa , Medios de Cultivo , MétodosRESUMEN
Penicillium janczewskii Zaleski is an efficient microorganism for the production of extracellular inulinases and grows rapidly on medium containing sucrose or inulin as carbon source. Maintenance of this filamentous fungus on inulin medium induces secretion of large amounts of inulinases, but the resulting mycelium has thinner cell walls that easily collapse and break. Woronin bodies in hyphae of P. janczewskii grown on sucrose and inulin substrates were observed. No significant differences in the number, location, size and shape of Woronin bodies and level of plugging were observed in cultures of the fungus grown on the two carbon sources. The data indicate that the presence of Woronin bodies in P. janczewskii could not be associated with more easily damaged hyphae, although the function of these organelles in pore plugging has been confirmed.
Penicillium janczewskii Zaleski é um microrganismo eficiente para a produção de inulisases extracelulares e cresce rapidamente em meio contendo sagarose ou inulina como fonte de carbono. A manutenção desse fungo filamentoso em meio com inulina induz a secreção de grandes quantidades de inulisanes, mas resulta na presença de um micélio com parede celulares mais finas, que facilmente colapsa e se danifica. A presença de corpúsculos de Woronin foi analisada nas hifas de P. janczewskii crescido em sacarose e inulina. Nenhuma diferença significativa foi observada no número, localização, tamanho e forma dos corpúsculos de Woronin e na obstrução dos poros dos septos nas culturas do fungo crescido nas duas diferentes fontes de carbono. Os resultados obtidos indicam que a presença dos corpúsculos de Woronin em P. janczewskii não pode ser associada com a presença de hifas mais facilmente danificadas, embora a função dessas organelas na obstrução dos poros dos septos tenha sido confirmada.