Miyoshi T, Iseki M, Konomi T, Imanaka H
J Antibiot (Tokyo). 1980 May;33(5):480-7. doi: 10.7164/antibiotics.33.480.
The degeneration of bicyclomycin-producing strains of Streptomyces sapporonensis resulted in sharply depressed bicyclomycin formation in a large scale fermentation. Degenerated strains, whose productivities were only 1/30 to 1/100 of normal strains, could not form aerial mycelia on glucose-BENNETT's agar; they were aerial mycelia negative strains (am-). Repeated transfers of culture, treatment of mycelia with acriflavin, mechanical agitation shock on mycelia or higher growth conditions stimulated the degeneration of producing strains, suggesting the involvement of extrachromosomal elements or plasmids in biosynthesis of bicyclomycin. Shake flask fermentation inoculated with a mixture of a normal high-producing strain and a degenerated low-producing strain resulted in sharply depressed bicyclomycin formation in proportion to the increase of low-producing strain added. It appears that the low-producing strain outgrew the high-producing strain.
日本链霉菌产生双环霉素的菌株发生退化，导致大规模发酵中双环霉素的形成急剧减少。退化菌株的生产力仅为正常菌株的1/30至1/100，在葡萄糖 - 贝内特琼脂上不能形成气生菌丝；它们是气生菌丝阴性菌株（am-）。反复传代培养、用吖啶黄素处理菌丝体、对菌丝体进行机械搅拌冲击或更高的生长条件会刺激生产菌株的退化，这表明染色体外元件或质粒参与了双环霉素的生物合成。用正常高产菌株和退化低产菌株的混合物接种摇瓶发酵，双环霉素的形成会随着添加的低产菌株数量的增加而急剧减少。似乎低产菌株的生长超过了高产菌株。
