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Mutagenic and lethal effects of near‐ultraviolet radiation (290–400 nm) on bacteria and phage
Author(s) -
Eisenstark A.
Publication year - 1987
Publication title -
environmental and molecular mutagenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 87
eISSN - 1098-2280
pISSN - 0893-6692
DOI - 10.1002/em.2850100311
Subject(s) - bacteria , ultraviolet radiation , microbiology and biotechnology , ultraviolet , biology , bacteriophage , mutagen , toxicology , chemistry , genetics , escherichia coli , carcinogen , radiochemistry , gene , physics , optoelectronics
Despite decades of study of the effect of near‐ultraviolet radiation (NUV) on bacterial cells, insights into mechanisms of deleterious alterations and subsequent recovery are just now emerging. These insights are based on observations that 1) damage by NUV may be caused by a reactive oxygen molecule, since H 2 O 2 may be a photoproduct of NUV; 2) some, but not all, of the effects of NUV and H 2 O 2 are interchangeable; 3) there is an inducible regulon ( oxyR ) that responds to oxidative stress and is involved in protection against NUV; 4) a number of NUV‐sensitive mutants are defective either in the capacity to detoxify reactive oxygen molecules or to repair DNA damage caused by NUV; and 5) recovery from NUV damage may not directly involve induction of the SOS response. Since several distinctly different photoreceptors and targets are involved, it is unknown whether NUV lethality and mutagenesis result from an accumulation of damages or whether there is a particularly critical photoeffect. To fully understand the mechanisms involved, it is important to identify the chromophore(s) of NUV, the mechanism of toxic oxygen species generation, the role of the oxidative defense regulon ( oxyR ), the specific lesions in the DNA, and the enzymatic events of subsequent repair.