球形芽孢杆菌的抗药标记及外源DNA的转化与表达

用亚硝基胍（NTG）对球形芽孢杆菌（Bacillussphaericus）进行化学诱变，筛选到利福平（Rif）和链霉素（Sm）二个标记菌株。抗药浓度均达100u／ml培养基。其抗药性状能够获得较好地遗传。用含溶葡球菌酶基因的质粒DNA对RifR菌株进行原生质体转化，酶基因在该抗药菌株中获得了高效表达。经摇瓶发酵试验，溶葡球菌酶的活性约为122u／ml培养液。

SELECTION OF DRUG-LABELLED BACILLUS SPHAERICUS AND STUDIES ON TRANSFORMATION AND EXPRESSION OF FOREIGN DNA

NTG was used to make chemical mutation for Bacillus sphaericus, RifR and SmR labelled strains were selected, which could resist drug as much as 100 u / ml.The resistance to drug was stably inherited. The RifR strain was used as recipient and the plasmid containing the lysostaphin gene was transfered into it by protoplasts.Results showed that the lysostaphin gene could be expressed stably at high level in Bacillus sphaericus and the lysostaphin activity was about 122 u / ml medium after shaking culture.