A pre-induction sporulation gene from Aspergillus nidulans.

Asexual sporulation in Aspergillus nidulans is an inducible developmental process controlled by genes that act before and after the inductive stimulus is applied. Genes that act before induction (pre-induction genes) potentially represent functions required for response to induction. This report describes the isolation and characterization of the acoB pre-induction gene which was cloned by complementation of a thermosensitive aconidial mutant followed by gene rescue.

Isolation of a sexual sporulation hormone from Aspergillus nidulans.

Psi factor is a substance produced by Aspergillus nidulans that induces premature sexual sporulation. Chromatographic analysis of psi-active extracts showed that psi activity resides in several different forms. Two of the forms, psiA1 and psiB1, have been isolated and have been shown to have closely similar compositions.

An endogenous inducer of sexual development in Aspergillus nidulans.

During development of the homothallic ascomycete Aspergillus nidulans, asexual sporulation is followed by sexual sporulation. We report here the detection of a solvent-extractable activity which inhibits asexual sporulation and stimulates premature sexual sporulation. This activity, called precocious sexual inducer (psi), is overproduced by certain mutants that are blocked in both modes of sporulation.

Mutants of Aspergillus nidulans blocked at an early stage of sporulation secrete an unusual metabolite.

Mutants of Aspergillus nidulans defective in conidiation (asexual sporulation) can be classified according to whether they are blocked before or after induction of conidiation. Mutants blocked before induction (preinduction mutants) appear to be unable to respond to the inducing stimulus and thus are defective in one of the earliest events in the sporulation process. Three preinduction mutants have been isolated and characterized.