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RESEARCH NOTE
Author(s) -
Lloyd R. E.,
Rinkenberger J. L.,
Hug B. A.,
Tuveson R. W.
Publication year - 1990
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.1751-1097.1990.tb08699.x
Subject(s) - riboflavin , auxotrophy , limiting , strain (injury) , escherichia coli , mutant , biochemistry , extracellular , chemistry , biology , anatomy , engineering , mechanical engineering , gene
— Two mutants of Escherichia coli unable to synthesize riboflavin were grown with limiting (2 µg m l ‐1 ) and non‐limiting (10 µg m l ‐1 ) concentrations of riboflavin. These riboflavin auxotrophs when grown to exponential phase with non‐limiting riboflavin are more sensitive to broad spectrum near‐ultraviolet light (NUV, 320–400 nm) inactivation than when they are grown with limiting riboflavin. Exponential phase cells of the riboflavin auxotrophs grown with limiting riboflavin are sensitized when irradiated in saline supplemented with riboflavin. This suggests that extracellular riboflavin is important as a NUV sensitizer when intracellular levels of riboflavin are reduced. The concentration of riboflavin in crude extracts from exponentially growing cells correlates well with the sensitivity of these mutants to NUV inactivation. The level of riboflavin supplementation has little effect on the NUV sensitivity of the parental strain.