Radial growth, asexual sporulation, and cleistothecia formation as well as extracellular chitinase and proteinase formation of Aspergillus nidulans were monitored in surface cultures in order to study the physiological role of extracellular hydrolase production in carbon-stressed cultures. We set up carbon-stressed and carbon-overfed experimental conditions by varying the starting glucose concentration within the range of 2.5 and 40 g/L. Glucose starvation induced radial growth and hydrolase production and enhanced the maturation of cleistothecia; meanwhile, glucose-rich conditions enhanced mycelial biomass, conidia, and cleistothecia production. Double deletion of chiB and engA (encoding an extracellular endochitinase and a β-1,3-endoglucanase, respectively) decreased conidia production under carbon-stressed conditions, suggesting that these autolytic hydrolases can support conidia formation by releasing nutrients from the cell wall polysaccharides of dead hyphae. Double deletion of prtA and pepJ (both genes encode extracellular proteases) reduced the number of cleistothecia even under carbon-rich conditions except in the presence of casamino acids, which supports the view that sexual development and amino acid metabolism are tightly connected to each other in this fungus.

• MeSH
• Aspergillus nidulans enzymology   growth & development   MeSH
• Cellulase genetics   MeSH
• Chitinases genetics   MeSH
• Fungal Proteins genetics   MeSH
• Glucose chemistry   MeSH
• Hydrolases genetics   MeSH
• Hyphae growth & development   MeSH
• Culture Media MeSH
• Mutation MeSH
• Peptide Hydrolases genetics   MeSH
• Gene Expression Regulation, Enzymologic MeSH
• Gene Expression Regulation, Fungal * MeSH
• Spores, Fungal growth & development   MeSH
• Gene Expression Regulation, Developmental MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Cellulase MeSH
• Chitinases MeSH
• Fungal Proteins MeSH
• Glucose MeSH
• Hydrolases MeSH
• Culture Media MeSH
• Peptide Hydrolases MeSH

Polyphasic characterization of the echinocandin B producer Aspergillus nidulans var. roseus ATCC 58397 strain was carried out to elucidate its taxonomical status. According to its carbon source utilization and secondary metabolite spectrum as well as the partial β-tubulin, calmodulin, and γ-actin gene sequences, A. nidulans var. roseus belongs to the Emericella rugulosa species. Auxotroph mutants of A. nidulans var. roseus ATCC 58397 and E. rugulosa CBS 171.71 and CBS 133.60 formed stable heterokaryons on minimal medium with several A. nidulans strains, and in the case of A. nidulans var. roseus, even cleistothecia were developed.

• MeSH
• Actins chemistry   genetics   metabolism   MeSH
• Aspergillus nidulans classification   genetics   metabolism   MeSH
• Echinocandins biosynthesis   MeSH
• Emericella classification   genetics   metabolism   MeSH
• Fermentation MeSH
• Fungal Proteins biosynthesis   chemistry   genetics   metabolism   MeSH
• Phylogeny MeSH
• Calmodulin chemistry   genetics   metabolism   MeSH
• Crosses, Genetic MeSH
• Mycological Typing Techniques MeSH
• Polymerase Chain Reaction MeSH
• Sequence Analysis, DNA MeSH
• Sterigmatocystin biosynthesis   MeSH
• Tubulin chemistry   genetics   metabolism   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Actins MeSH
• echinocandin B MeSH Browser
• Echinocandins MeSH
• Fungal Proteins MeSH
• Calmodulin MeSH
• Sterigmatocystin MeSH
• Tubulin MeSH

N-Acetyl-D-glucosamine, chito-oligomers and carbon starvation regulated chiA, chiB, and nagA gene expressions in Aspergillus nidulans cultures. The gene expression patterns of the main extracellular endochitinase ChiB and the N-acetyl-beta-D-glucosaminidase NagA were similar, and the ChiB-NagA enzyme system may play a morphological and/or nutritional role during autolysis. Alterations in the levels of reactive oxygen species or in the glutathione-glutathione disulfide redox balance, characteristic physiological changes developing in ageing and autolyzing fungal cultures, did not affect the regulation of either the growth-related chiA or the autolysis-coupled chiB genes although both of them were down-regulated under diamide stress. The transcription of the chiC gene with unknown physiological function was repressed by increased intracellular superoxide concentration.

• MeSH
• Acetylglucosamine pharmacology   MeSH
• Aspergillus nidulans enzymology   genetics   physiology   MeSH
• Chitinases biosynthesis   genetics   MeSH
• DNA, Fungal genetics   MeSH
• Enzyme Induction MeSH
• Fungal Proteins biosynthesis   genetics   MeSH
• Phylogeny MeSH
• Oligosaccharides pharmacology   MeSH
• Oxidation-Reduction MeSH
• Reactive Oxygen Species metabolism   MeSH
• Gene Expression Regulation, Fungal * MeSH
• Carbon metabolism   MeSH
• Computational Biology MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Acetylglucosamine MeSH
• Chitinases MeSH
• DNA, Fungal MeSH
• Fungal Proteins MeSH
• Oligosaccharides MeSH
• Reactive Oxygen Species MeSH
• Carbon MeSH