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PHOTOSENSITIVITY IN CAROTENOIDLESS MUTANTS OF MICROCOCCUS LUTEUS (SARCINA LUTE A) : NON‐PHOTODYNAMIC MENAQUINONE DESTRUCTION IN WHITE LIGHT
Author(s) -
Prebble John N.
Publication year - 1981
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.1751-1097.1981.tb05508.x
Subject(s) - micrococcus luteus , sarcina , photosensitivity , chemistry , visible spectrum , biochemistry , photochemistry , bacteria , biology , escherichia coli , genetics , physics , quantum mechanics , gene , optoelectronics
–The photosensitivity of a carotenoidless mutant strain has been examined in terms of its loss of viability and loss of menaquinone when subjected to high intensity visible light. Cell viability and menaquinone are protected by cyanide (an inhibitor of cytochrome oxidation), by malate (a substrate for the respiratory chain) and by nitrogen although the protection of menaquinone is less in nitrogen. Evidence is presented in support of the view that oxidised membrane‐bound menaquinone is more photolabile in visible light than the reduced form. Loss of menaquinone is seen as the primary cause of death in these obligately aerobic carotenoidless cells and the role of oxygen as indirect by converting reduced menaquinone to the oxidised form. Evidence is also presented that the cause of cell death in red light in the presence of an exogenous photosensitizer, toluidine blue, is different from that in white light.