Induced Mutations in Molds

(From the Summary)

This experiment was originally intended to investigate the mutagenic effect of certain carcinogenic drugs, and to determine the possible relationship between mutation in micro-organisms and cancer in higher tissue. Attempts to produce visible morphological mutations or modified lactose fermentation in Escherichia coli and Aerobacter aerogenes by placing the various drugs in the culture media did not yield any mutations. These same materials were then used on Aspergillus niger, by placing the chemical on absorbent discs on petri plates and examining the mold in the surrounding area for variations. This procedure also failed to yield mutations.

Spores of Aspergillus niger were irradiated with ultraviolet light and plated. The resulting colonies were examined for morphological mutations. Three such variations were found and described. The processes for extraction of the pigment of one of the variants and the chemical identification of it and other components of the mycelia are described.