Strain Specificity and Production of Antibiotic Substances

Abstract

Actinomycin is produced by different spp. of the genus Streptomyces. The yield and purity of the antibiotic depend upon the nature of the culture. One organism yielded about 10 times as much actinomycin as the original S. antibioticus. Another culture gave a lower yield than 5. antibioticus, but a purer product was obtained. The nature and activity of the 2d fraction accompanying the actinomycin, namely actinomycin B, also varied for the different cultures; however, its antibiotic spectrum was similar to that of actinomycin. Because of the insignificant yields of the B fraction, and because of the suggestion that its activity is due to traces of actinomycin A present as impurities, it is proposed to abandon the name of "actinomycin B" and to change the name of "actinomycin A" to "actinomycin.".