Reference

A DNA-repair proficient strain of Escherichia coli which is highly sensitive to mutagenic acridines in plate tests

A DNA-repair proficient strain of Escherichia coli which is highly sensitive to mutagenic acridines in plate tests. Thomas, Susan M.; MacPhee, D. G. (Dep. Microbiol., La Trobe Univ., Bundoora 3083, Australia). Mutat. Res., 131(5-6), 193-6 (English) 1984. CODEN: MUREAV. ISSN: 0027-5107. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacology) Section cross-reference(s): 4 9-Aminoacridine (I) [90-45-9] 5-100, proflavine [92-62-6] 10-50 , and acriflavine [65589-70-0] 5-100 mg/plate induced back mutations to Lac+ in E. coli strain DG1669 but only I induced back mutations to His+ in Salmonella typhimurium strain TA97. Thus, even though strain DG1669 is DNA-repair proficient and does not carry the mutation-enhancing plasmid pKM101, it appears to be a more useful tester strain than TA97.

The SOS-function-inducing activity of chemical mutagens in Escherichia coli

The SOS-function-inducing activity of chemical mutagens in Escherichia coli. Ohta, Toshihiro; Nakamura, Naoko; Moriya, Masaaki; Shirasu, Yasuhiko; Kada, Tsuneo (Inst. Environ. Toxicol., Kodaira 187, Japan). Mutat. Res., 131(3-4), 101-9 (English) 1984. CODEN: MUREAV. ISSN: 0027-5107. DOCUMENT TYPE: Journal CA Section: 4 (Toxicology) The SOS (error-prone DNA repair) function-inducing activities of 42 chem. mutagens were investigated in E. coli K12. The induction of the SOS function was assayed by monitoring the b-galactosidase [9031-11-2] activity in the sulA::lacZ fusion strain PQ37. To correct for the inhibitory effects of test chems. on mRNA or protein synthesis, the level of the constitutive alk. phosphatase [9001-78-9] was assayed in parallel. Most of the mutagens reported to be mutagenic to the Ames' Salmonella strains showed the SOS-function-inducing activity. The inducible SOS repair may be responsible for not only base-change mutations but also frameshift mutations. However, 9-aminoacridine [90-45-9], ethidium bromide [1239-45-8], and 4-nitro-o-phenylenediamine [99-56-9] did not induce the SOS function, suggesting that the mutagenesis induced by these mutagens may occur independently of SOS repair. Present results support the SOS mutagenesis model that error-prone SOS repair plays an important role in mutagenesis induced by most chem. mutagens.