士的宁对鼠伤寒沙门氏菌的重组效应。
A recombinagenic effect of strychnine in Salmonella typhimurium.
作者信息
Hoffmann G R, Sprague K M, Wrobel J A, Wroblewski D H
机构信息
Department of Biology, College of the Holy Cross, Worcester, Massachusetts 01610.
出版信息
Environ Mol Mutagen. 1987;10(1):27-33. doi: 10.1002/em.2850100105.
The aroC321 allele in Salmonella typhimurium permits a positive selection for genetic duplications. Bacteria that contain a large genetic duplication are detected as tryptophan prototrophs in aroC321 strains and occur at a spontaneous frequency greater than 1/10(4) cells plated on the selection medium. Duplications originate by a recombinational mechanism, and the induction of duplications by chemicals or radiation may therefore be considered to be a recombinagenic effect. We have found that strychnine is a potent recombinagen in this system; it causes a dose-dependent increase in the frequency of genetic duplications, and very high frequencies of duplications are recovered at high doses. In contrast, brucine, the 2,3-dimethoxy derivative of strychnine, caused no increase in duplication frequencies under the identical conditions.
鼠伤寒沙门氏菌中的aroC321等位基因允许对基因重复进行正向选择。在aroC321菌株中，含有大量基因重复的细菌被检测为色氨酸原养型，其自发频率高于接种在选择培养基上的1/10(4)个细胞。重复通过重组机制产生，因此化学物质或辐射诱导的重复可被视为重组诱变效应。我们发现士的宁在该系统中是一种有效的重组诱变剂；它导致基因重复频率呈剂量依赖性增加，在高剂量下可获得非常高的重复频率。相比之下，士的宁的2,3 -二甲氧基衍生物马钱子碱在相同条件下不会导致重复频率增加。
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