Photosensitized inactivation of plasmids and bacteriophage #lambda#: the relative contribution to lethal effect of monoadducts and diadducts of 8-methoxypsoralen and their repair in SOS-induced Escherichia coli cells

摘要

The curves of UV (254 nm)- inactivation, and inactivation by furocoumarin derivatives + UVA radiation (PUVA) of bacteriophage #lambda# and biologically active plasmid pBRB22 were measured using Escherichia coli K12 bacteria with different defects of DNA repair system as a ghost. The ratio of mono- and diadducts (interstrand cross-links) of 8-methoxypsoralen was determined that are formed after treating the DNA of pBR322 and bacteriophage #lambda# with PUVA. It is shown that, on the average, about five monoadducts per one diadduct are formed in DNA of pBRB22, and about 0.9 monoadducts per one diadduct are formed in #lambda# phage DNA. An increased (up to 50%) efficiency of SOS-repair of monoadducts of 8-methoxypsoralen in DNA of pBR322 and #lambda# in the presence of plasmid pKM101 muc~+ (incN) was found.