MacPhee D G
Mutat Res. 1977 Oct;45(1):1-6. doi: 10.1016/0027-5107(77)90036-7.
Ultraviolet-induced, gamma-induced and spontaneous mutation yields were studied in two different auxotrophic strains of Salmonella typhimurium in the presence and absence of the UV-protecting drug resistance transfer factor R-Utrecht. One strain, carrying the hisC527 (amber) mutation, showed significantly increased spontaneous, UV- and gamma-induced mutability in the presence of the R-Utrecht plasmid. The other strain, carrying the trpD1 mutation (thought to be a missense mutation), also showed significantly increased UV mutability in the presence of the R-Utrecht plasmid. The other strain, carrying the trpD1 mutation (thought to be a missense mutation), also showed significantly increased UV mutability in the presence of the R factor, but appeared to show no significant increase in spontaneous mutability and only a very slight increase in gamma-mutability when carrying the R factor. These results demonstrate that the R-Utrecht plasmid, known to enhance UV-induced mutation yields in S. typhimurium, can also significantly enhance both spontaneous and gamma-induced mutation yields in this species. The latter effects are not so discernible with all markers, however, as shown by the results with strains carrying the trpD1 mutation. Enhancement of spontaneous mutability thus appears to be correlated with enhancement of gamma-mutability rather than UV mutability.
在存在和不存在紫外线防护性耐药转移因子R - 乌得勒支的情况下，研究了鼠伤寒沙门氏菌两种不同营养缺陷型菌株中的紫外线诱导突变、γ射线诱导突变和自发突变率。一种携带hisC527（琥珀型）突变的菌株，在存在R - 乌得勒支质粒的情况下，自发、紫外线和γ射线诱导的突变率显著增加。另一种携带trpD1突变（被认为是错义突变）的菌株，在存在R - 乌得勒支质粒时，紫外线诱导的突变率也显著增加。另一种携带trpD1突变（被认为是错义突变）的菌株，在存在R因子时，紫外线诱导的突变率同样显著增加，但携带R因子时自发突变率似乎没有显著增加，γ射线诱导的突变率仅略有增加。这些结果表明，已知能提高鼠伤寒沙门氏菌紫外线诱导突变率的R - 乌得勒支质粒，也能显著提高该菌种的自发突变率和γ射线诱导突变率。然而，如携带trpD1突变菌株的结果所示，并非所有标记的后一种效应都如此明显。自发突变率的提高似乎与γ射线诱导突变率的提高相关，而非与紫外线诱导突变率相关。
