大肠杆菌菌种空间变异的研究

Mutation Induced by Space Conditions in Escherichia coli Strains.

为研究微生物菌种在空间条件下产生的变异，在利用我国发射的返回式卫星上，搭载了适用于突变研究的大肠杆菌菌株ＣＳＨ１０８、Ａ３和Ａ２，使用了三种搭载方式。卫星返回后，测定了菌种的存活及产生的ｌａｃＩ－突变和Ａｒｇ＋回复突变的频率。结果表明：大肠杆菌在空间条件下是可以存活的；经小生物舱搭载的Ａ３菌株产生的ｌａｃＩ－突变体的频率是地面对照的６７倍；铅罐中搭载的ＣＳＨ１０８菌株产生的Ａｒｇ＋的回复突变频率是地面对照的１０倍左右，而且回复体中无义抑制基因的突变频率明显增加。由此可见，空间条件有可能显著地提高微生物中某些基因的突变频率，空间诱变可望成为获得微生物优良菌种的有效途径之一。

To study the mutagenesis of microorganism under space conditions, three Escherichia coli strains CSH108, A2 and A3,were flown on board the Chinese recoverable satellite (JB1-B9611020) in Oct. 1996.Three ways of sample boarding were designed.After recovery, survival and frequency of lacl mutation and Arg+ reversion were determined in the flight strains.The results showed that: E.coli strains could survive after the flight conditions.The lacI mutation frequency of A3 strain in the biocabin was sixty-seven times that of the ground control,the Arg+ reversion frequency of CSH108 in the lead chamber,was ten times that of the ground control;and among the revertants the mutation frequency of nonsense suppressor increased remarkably. The results indicate that the space conditions may greatly enhance the mutation frequency of certain genes in the microorganism and may provide an effective method for microorganism breeding.