1887

Abstract

Summary: Five mutants of strain 2 (ColE1), initially detected because they released little or no colicin when tested on solid medium, proved to be sensitive to ultraviolet light (u.v.). Further testing indicated that one of the mutants was deficient in genetic recombination and was probably a -type mutant, while three of the others were deficient in DNA polymerase activity and appeared to be typical mutants. The fifth mutant was less sensitive than the others to methyl methanesulphonate, showed reduced proficiency in genetic recombination, and was of approximately normal u.v. mutability. This mutant may be a counterpart of the class known as in . All five mutants degraded significantly more of their DNA following exposure to u.v. than did the wild-type strain. The -type mutant and the possible mutant also degraded significantly more of their DNA spontaneously than did the wild-type. Treatment with visible light and acridine orange (photodynamic treatment) caused no significant degradation of DNA in the wild-type strain, a highly significant increase in the extent of DNA degradation in a mutant, and a decrease in the extent of degradation in the -type mutant.

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/content/journal/micro/10.1099/00221287-101-1-143
1977-07-01
2019-10-19
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http://instance.metastore.ingenta.com/content/journal/micro/10.1099/00221287-101-1-143
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