title: Simultaneous loss of multiple differentiated functions in aerial mycelium-negative isolates of streptomycetes.
abstract: Germination and outgrowth of spores of Streptomyces alboniger, Streptomyces scabies, and Streptomyces violaceus-ruber in the presence of intercalating dyes resulted in a high frequency (2 to 20%) of occurrence of aerial mycelium-negative (Amy-) isolates. Coincident with the appearance of the Amy- trait was the loss of several differentiated functions, including the characteristic pigments and earthy odor of the wild types. All S. alboniger, 27% of S. scabies, and 39% of the S. violaceus-ruber Amy- isolates were arginine auxotrophs. The missing enzyme step was identified as argininosuccinate synthetase by using a sensitive microassay for estimation of enzyme activity. The remainder of the S. scabies and S. violaceus-ruber isolates were prototrophs. In addition, S. alboniger Amy- isolates failed to produce or respond to the stimulator of aerial mycelium formation isolated from the wild type. The Amy- isolates did not revert to either Amy+ of Arg+. The lack of any detectable reversion, coupled with the high frequency of curing, supports the idea that a deletion of genetic material, possibly a plasmid, has occurred.
mesh_terms: D000165:Acridine Orange / Q000494:pharmacology; D000167:Acriflavine / Q000494:pharmacology; D001124:Argininosuccinate Synthase / Q000235:genetics; D010641:Phenotype; D010860:Pigments, Biological / Q000096:biosynthesis; D012717:Sesquiterpenes / Q000378:metabolism; D013045:Species Specificity; D013171:Spores, Bacterial / Q000187:drug effects / Q000502:physiology; D013302:Streptomyces / Q000187:drug effects / Q000235:genetics / Q000502:physiology*
chemical_list: D010860:Pigments, Biological; D012717:Sesquiterpenes; D000167:Acriflavine; D001124:Argininosuccinate Synthase; D000165:Acridine Orange