Premium
The significance of the D ewar valence photoisomer as a UV radiation‐induced DNA photoproduct in marine microbial communities
Author(s) -
Meador Jarah A.,
Baldwin Amy J.,
Pakulski J. Dean,
Jeffrey Wade H.,
Mitchell David L.,
Douki Thierry
Publication year - 2014
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.12414
Subject(s) - bacterioplankton , biology , dna , pyrimidine , marine bacteriophage , candida antarctica , photochemistry , biophysics , botany , biochemistry , chemistry , bacteria , phytoplankton , genetics , nutrient , ecology , enzyme , lipase
Summary Induction of pyrimidine dimers in DNA by solar UV radiation has drastic effects on microorganisms. To better define the nature of these DNA photoproducts in marine bacterioplankton and eukaryotes, a study was performed during a cruise along a latitudinal transect in the P acific Ocean. The frequency of all possible cyclobutane pyrimidine dimers, pyrimidine (6‐4) pyrimidone photoproducts (64 PPs ) and their related D ewar valence isomers ( DEWs ) was determined by high‐performance liquid chromatography–mass spectrometry. Studied samples were bacterioplankton and eukaryotic fractions isolated from sea water either collected before sunrise or exposed to ambient sunlight from sunrise to sunset. Isolated DNA dosimeters were also exposed to daily sunlight for comparison purposes. A first major result was the observation in all samples of large amounts of DEWs , a class of photoproducts rarely considered outside photochemical studies. Evidence was obtained for a major role of UVA in the formation of these photoisomerization products of 64 PPs . Considerations on the ratio between the different classes of photoproducts in basal and induced DNA damage suggests that photoenzymatic repair ( PER ) is an important DNA repair mechanism used by marine microorganisms occupying surface seawater in the open ocean. This result emphasizes the biological role of DEWs which are very poor substrate for PER .