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THE EXPRESSION OF LIQUID HOLDING RECOVERY IN ULTRAVIOLET‐IRRADIATED ESCHERICHIA COLI REQUIRES A DEFICIENCY IN GROWTH MEDIUM‐DEPENDENT DNA REPAIR
Author(s) -
Tang MoonShong,
Smith Kendric C.
Publication year - 1980
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1980.tb04053.x
Subject(s) - repressor lexa , recbcd , escherichia coli , strain (injury) , dna repair , mutant , biology , irradiation , dna , mutation , dna damage , microbiology and biotechnology , wild type , growth medium , chemistry , bacteria , genetics , gene , repressor , gene expression , physics , anatomy , nuclear physics
— Ultraviolet (UV) irradiated Escherichia coli K‐12 recA cells (but not rec + cells) show enhanced survival if they are held in buffer prior to plating for viability. To understand the role of the recA mutation in this liquid holding recovery (LHR) phenomenon, we have studied LHR in a temperature sensitive recA 200 mutant. The detection of LHR requires that the irradiated cells be recA when they are plated on growth medium, but the recA deficiency plays no role during liquid holding (LH). We conclude that it is the extreme sensitivity of recA cells in growth medium to unrepaired DNA daughter‐strand gaps that magnifies the beneficial effects of the excision repair of DNA lesions during LH. Furthermore, we demonstrate a correlation between a strain's inability to perform growth medium dependent repair and its ability to express LHR. The relative amount of LHR was: recA > recF > lexA > recB > wild type (with the recB and wild‐type strains showing negative LHR). Two strains did not show this correlation; the uvrD strain showed less LHR than expected from its UV radiation sensitivity, while the polA strain showed more. The molecular bases for these exceptions are explored.