摘要
从鼠伤寒沙门氏菌的ＴＴ１２３０６（ｐｕｒＤ∷ｌａｃ）株出发，对８６个对数生长期培养物作了诱变处理，在Ｅ＋Ａｄｏ＋Ｘｇａｌ平板上得到６６个独立的白色或浅蓝色菌落，经测定它们在阻遏和去阻遏条件下的β半乳糖苷酶活性、回复突变频率、突变位点的转导分析和显性实验，证明其中１１株为嘌呤生物合成途径中的超阻遏突变体。
? Starting from strain of Salmonella typhimurium purD∷lac,86 exponential cultures were mutagenized with NTG and white or light blue clones on E+Ado+Xgal plate were selected as candidates of pusRs mutant.Total 66 independent candidate stains were obtained.By assaying their βgalactosidase activity under the repressed and derepressed conditions,determing their frequency of revertional mutation,Conducting transductional analysis of mutational site and dorminance test,11 candidates strains were proved to be superrepressor mutants.These mutants are useful for studying the expression regulation of purine biosynthetic gene and relationship between protein structure and function in general.
基金
国家自然科学基金
关键词
鼠伤寒沙门氏菌
反式调节基因
超阻遏突变体
Salmonella typhimurium,Transregulational gene purR,Superrepressor mutant purRs
