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OYGEN DEPENDENCE AND REPAIR OF LETHAL EFFECTS OF NEAR ULTRAVIOLET AND VISIBLE LIGHT *
Author(s) -
WEBB ROBERT B.,
LORENZ JOHN R.
Publication year - 1970
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.1751-1097.1970.tb06060.x
Subject(s) - escherichia coli , strain (injury) , ultraviolet , oxygen , erg , chemistry , microbiology and biotechnology , materials science , biology , optoelectronics , biochemistry , retinal , organic chemistry , gene , anatomy
— –Lethality in a repairable strain (WP2) and an excision repair deficient strain (WP2h cr ) of Escherichia coli was studied at wavelengths of 254, 313, 365, and 390–750 nm. Survival curves were empirically fitted to the expression S = 1 ‐ (1‐e ‐kl )“, where S is the fraction surviving, D is the incident dose in ergs mm ‐2 , k is the inactivation constant in units of (erg mm ‐2 ) ‐1 and n is the ‘shoulder constant’. The repairable sector ( k (hcr ‐ )– k ( hcr ‐ ) lk ( hcr ‐ ), a conservative estimate of the repair capability of E. coli WP2, was 0.91 at 254 nm, 0.92 at 313 nm, 0.60 at 365 nm, and 0.13 at 390–750 nm. Although there was no oxygen enhancement of inactivation at 254 nm and 313 nm, a strong enhancement was identified at 365 nm and 390–750 nm. These results suggest that oxygen‐dependent damage induced by near u.v. (365 nm) can be partially repaired by the excision‐repair system in E. coli.