Glycerol non-utilizing mutants in Neurospora crassa

Abstract

The net replication method. Methods were developed for screening of glycerol non-utilizing mutants from Neurospora crassa. The strains utilized produce only mononucleate conidia (pefi, microconidia). Some strains were inherently colonial, independent of temperature, others were of the cot (colonial, temperature-sensitive) type. Mutagen (ultraviolet light) treated conidia were spread on plates with medium containing glucose as the source of carbon, and overlaid with a disc of Terylene net. Outgrowing colonies were transferred with the nets to plates with glycerol as carbon. Replication was accomplished by a period of growth. Non-replicating colonies were isolated from the glucose plates and retested as presumptive glycerol non-utilizing mutants.GfyceroI non-utilizing mutants. One glycerol non-utilizing mutant, gfy-u (234), appears otherwise physiologically normal and segregates as a nuclear gene in crosses. Another, gly-u (245), has a very long lag period (ca 2-3 weeks) on glycerol medium, but eventually adapts itself to growth on this carbon source. Photographs of replicated colonies as well as mutants are presented. The biochemical pathways of glycerol metabolism are outlined from work by various authors, and the present studies are discussed in this connection.