[Studies on the conidial differentiation of "Neurospora crassa" VI.--Functional anomalies of the conditional aconidial mutant "amycelial" (author's transl)].

Studies using the morphological mutant "amycelial"--a conditional, aconidial strain of N. crassa--have revealed certain consistent functional and biochemical differences from wild type strains showing normal morphology and conidia formation. Thus it was found that the mutant strain showed an abnormal utilization of protein reserves at a time when there is extensive degradation during conidiogenesis in wild type. In addition, the mutant exhibited abnormally low oxygen consumption and free amino acid pools depressed nearly 3/4 with respect to wild type. All of these findings are consistent with earlier work linking conidiogenesis to aerobic oxidative processes and suggest that catabolic reactions particularly regarding protein breakdown may be important to conidiogenesis from the standpoint of the synthesis of new conidial proteins and for the supply of endogenous energy reserves during the process. The aconidial character of "amycelial" could be partially alleviated on solid acetate medium supplemented with amino acids, especially tryptophan or histidine. Conidiation was also induced by cyclic-AMP, even on sucrose medium. A polymer strongly antigenic in rabbits was found to be released into growth medium by the mutant but not by wild type cultures, providing a possible clue to the immediate cause of the abnormal morphology seen in "amycelial". This substance appears to be a glycopeptide containing a few hexoses and amino acids associated with polyphosphate.