McBeth D L
Department of Microbiology, City University of New York Medical School/Sophie Davis School of Biomedical Education, City College, New York 10031.
J Bacteriol. 1989 Feb;171(2):975-82. doi: 10.1128/jb.171.2.975-982.1989.
The effect of plasmid CAM-OCT on responses to UV irradiation was compared in Pseudomonas aeruginosa, in Pseudomonas putida, and in Pseudomonas putida mutants carrying mutations in UV response genes. CAM-OCT substantially increased both survival and mutagenesis in the two species. P. aeruginosa strains without CAM-OCT exhibited much higher UV sensitivity than did P. putida strains. UV-induced mutagenesis of plasmid-free P. putida was easily detected in three different assays (two reversion assays and one forward mutation assay), whereas UV mutagenesis of P. aeruginosa without CAM-OCT was seen only in the forward mutation assay. These results suggest major differences in DNA repair between the two species and highlight the presence of error-prone repair functions on CAM-OCT. A number of P. putida mutants carrying chromosomal mutations affecting either survival or mutagenesis after UV irradiation were isolated, and the effect of CAM-OCT on these mutants was determined. All mutations producing a UV-sensitive phenotype in P. putida were fully suppressed by the plasmid, whereas the plasmid had a more variable effect on mutagenesis mutations, suppressing some and producing no suppression of others. On the basis of the results reported here and results obtained by others with plasmids carrying UV response genes, it appears that CAM-OCT may differ either in regulation or in the number and functions of UV response genes encoded.
在铜绿假单胞菌、恶臭假单胞菌以及携带紫外线反应基因突变的恶臭假单胞菌突变体中，比较了质粒CAM - OCT对紫外线照射反应的影响。CAM - OCT显著提高了这两个物种的存活率和诱变率。不含CAM - OCT的铜绿假单胞菌菌株比恶臭假单胞菌菌株表现出更高的紫外线敏感性。在三种不同的检测方法（两种回复突变检测和一种正向突变检测）中，很容易检测到无质粒恶臭假单胞菌的紫外线诱导诱变，而不含CAM - OCT的铜绿假单胞菌的紫外线诱变仅在正向突变检测中可见。这些结果表明这两个物种在DNA修复方面存在主要差异，并突出了CAM - OCT上存在易出错的修复功能。分离出了许多携带影响紫外线照射后存活率或诱变率的染色体突变的恶臭假单胞菌突变体，并确定了CAM - OCT对这些突变体的影响。在恶臭假单胞菌中产生紫外线敏感表型的所有突变都被该质粒完全抑制，而该质粒对诱变突变的影响则更具变数，抑制了一些突变，而对其他一些突变则没有抑制作用。根据此处报道的结果以及其他人用携带紫外线反应基因的质粒获得的结果，似乎CAM - OCT在调控方面或所编码的紫外线反应基因的数量和功能方面可能存在差异。
