通过接合转移将质粒pSC123上的转座子嘶随机插入到DLL-E4基因组DNA中,从大约8,000个突变株中得到1株温度敏感型突变株MT54。根据转座子上的已知序列设计引物以MT54基因组DNA为模板进行PCR扩增,证实MT54的染色体中有转座子插入。MT54在30℃条件下能够以对硝基苯酚(p-nitrophenol,PNP)为唯一碳源生长,但在37℃不能生长。格里斯试色剂法检测NO2^-的生成情况进一步证明了MT54的这种特性。通过30℃和37℃两种温度条件下MT54和原始出发菌株DLL-FA对PNP和对苯二酚降解情况的比较,推测温敏突变位点可能发生在与PNP降解相关的基因中。
A temperature-sensitive mutant strain was isolated after transposon mutagenesis with Tn5 and named MT54. PCR was carried out with primers designed according to the sequence of transposon, the PCR products showed that the MT54 carried transposon in the genome. The mutant grew well at 30℃ in minimal medium (MM) containing p-nitrophenol (PNP) as sole carbon source, while it cannot grow at 37℃ in the same medium, NO2^- detection results also proved that. Comparing the degradation rate of PNP and hydroquinone of MT54 and DLL-E4 at different temperature, it was speculated that the mutant site locate in the PNP degradation related genes.