Pessoni Rosemeire A B, Freshour Glenn, Figueiredo-Ribeiro Rita de Cássia L, Hahn Michael G, Braga Marcia R
Universidade Metodista de São Paulo, CP 5002, São Bernardo do Campo, SP 09735-460, Brazil.
Mycologia. 2005 Mar-Apr;97(2):304-11. doi: 10.3852/mycologia.97.2.304.
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.
詹氏青霉是一种从草本斑鸠菊（菊科）根际分离出的丝状真菌，在含有蔗糖或菊粉作为碳源的培养基上生长迅速。在菊粉培养基上培养詹氏青霉会诱导分泌具有高菊粉酶活性的蛋白质，但会导致菌丝体容易塌陷和断裂。我们评估了菊粉对真菌生长和菌落形态以及对细胞壁结构和组成的影响，并与在含蔗糖培养基上的生长和细胞壁特征进行了比较。在含有1%（w/v）蔗糖或菊粉的琼脂察氏培养基上生长的詹氏青霉，其菌落颜色和形态存在差异，尽管在两种碳源上的生长速率相似。扫描电子显微镜显示，在含菊粉培养基上生长的真菌的菌丝比在蔗糖上培养的真菌的菌丝细得多。使用透射电子显微镜对5天龄培养物进行的超微结构分析表明，在菊粉或蔗糖培养基上生长的菌丝之间，细胞壁厚度存在显著差异。从在两种碳源上生长的培养物中分离出的细胞壁的总碳水化合物和蛋白质含量未检测到差异。糖基组成分析表明，葡萄糖和半乳糖是细胞壁中主要的中性单糖，但未显示出因碳源而产生的差异。糖基连接组成分析表明，当詹氏青霉在含菊粉培养基上生长时，菌丝壁中以3-连接的吡喃葡萄糖基为主。我们的结果表明，以菊粉作为唯一碳源生长会导致詹氏青霉的菌丝体结构发生变化，从而导致菌丝壁的物理和生物学特性发生改变。
