The Ratio between Lethal and Mutagenic Damages in the DNA of Plasmids and Bacteriophages Induced by 8-Methoxypsoralen Plus UV (λ ≥ 320 nm) Treatment

• Published in: Russian journal of genetics 2021-07, Vol.57 (7), p.795-803
• Main Authors: Kotova, V. Yu, Abilev, S. K., Zavilgelsky, G. B.
• Format: Article
• Language: English
• Subjects: Animal Genetics and Genomics; Biomedical and Life Sciences; Biomedicine; General Genetics; Human Genetics; Microbial Genetics and Genomics
• ISSN: 1022-7954; 1608-3369
• DOI: 10.1134/S1022795421070097

The K -ratio between diadducts ( D ) and monoadducts ( M ) induced by 8-methoxypsoralen (8-MOP) in the DNA packed in the head of bacteriophage λ and in the DNA of pBR322 plasmid under UV irradiation (λ ≥ 320 nm) was measured. The probabilities of UVR excision repair of 8-MOP monoadducts ( P ) and of SOS repair of 8-MOP diadducts and monoadducts ( S and S m ) were determined. P was measured using an angular derivative of angelicin. It was demonstrated that P = 0.86. S and S m were determined using bacteriophage λ 11 treated with 8-MOP + UV (λ ≥ 320 nm) or 8-MOP + UV (λ ≥ 380 nm) and inoculated either onto bacteria pre-irradiated with short-wave UV light (λ = 254 nm) or onto bacteria with constitutive synthesis of the SOS regulon genes, as well as onto bacteria containing the pKM101 plasmid. In bacteriophage λ 11 , the level of W-reactivation (α) and the frequency of W-mutagenesis of clear mutations ( m ) were determined. It was demonstrated that 8-MOP diadducts (“crosslinks”) were repaired by the bacterial SOS system with the probability S = 0.28–0.29, and 8-MOP monoadducts were repaired by the bacterial SOS system with the probability S m = 0.41 only with the participation of the MucA’ 2 B enzyme, the genes for which were located in the conjugative plasmid pKM101.