必特霉素基因工程菌航天育种的研究

探讨航天技术对必特霉素基因工程菌的育种效果。我国返回式搭载卫星对基因工程必特霉素菌种进行了航天育种，共搭载4个菌株以沙土、甘油、斜面等不同方式，经受航天环境条件处理后计算其孢子存活率、营养缺陷型出现率及菌株的发酵效价。在本实验条件下菌株的存活率均很低，尤其是沙土方式的致死率为100％，甘油及斜面孢子的致死率分别为99．79％～100％和99．81％～100％。营养缺陷型出现率为1．65％。存活菌株的负突变率高于正突变率。经筛选从408株正突变株获得了发酵效价提高11．3％～14．5％的菌株。航天技术有可能应用于基因工程必特霉素的育种，但适于其育种的空间条件必须经过详尽而细致的研究和控制。

Studies on Space-Flight Breeding of Genetically Engineered Strain of Biotechmycin

To explore the spaceflight effect on breeding of genetically engineered strain of biotechmycin, spores from 4 strains embedded in sand, kept in 20% glycerol or grown on slants were carried on a recoverable satellite for 18 days. After recovery the spores were separated, the spore mortality rate and the occurrence of auxotrophy of strains were estimated. Fermentation titer of the strains was determined and mutation rate was calculated. The results showed that high mortality was shown in every case of studies ,that is 100% of mortality with the sand kept spores and 99. 81%-100% with the slant embedded spores, 99. 79%-100% with the glycerol grown spores. The occurrence of the auxotroph was about 1.65%. Negative mutation was dominated over positive mutation in terms of antibiotic production. Two strains showing 11.3 %- 14. 5 % of increasing of the antibiotic production were obtained after careful selection from 408 positive mutants. Spaceflight technique may play a positive effect on fermentation yield of genetically engineered strain of biotechmycin, but the spaceflight breeding condition must be well studied and carefully designed in order to obtain suitable mortality rate and desirable yield improvement.