ISOLATION AND STUDIES OF THE PLASMID FROM STREPTOMYCES HYGROSCOPICUS VAR. YINGCHENGENSIS
Shi Xian-ming and Zhou Qi(Agricultural Antibiotic Laboratory, Huazhong Agricultural University, Wuhan)
Based on the results of the experiments, YEME medium containing 13% sucrose was suitable for the growth of antibiotic 5102 producing strain,StrePtom-yces hygroscopicus var. Yingchengensis 10-22, in which mycelia of more biomass and better dispersed state were grown.A kind of plasmid DNA, named pSH47, was first isolated fom Streptomyces hygroscopicus var. Yingchengensis 10-22 with the method improved by raising the concentration of China-made lysozyme and prolonging the ly-sozyme treatment on the basis of T. Kieser's method.The existence of pasmid pSH47 was further confirmed by testing the ability of it to confer pock formation. The same plasmid bands appeared on an agarose gel by screening for the crude extcacis from Streptomyces hygroscopicus var.Yingchengensis 10-22 and several strain 10-22's block mutants, which had been gained by treating strain 10-22 with acridine orange and lost the whole or parts of the abilities producing three kinds of antibiotics 5102.