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THE INFLUENCE OF SEMI‐DEHYDRATION ON THE RESPONSE OF STREPTOCOCCUS LIQUEFACIENS TO ULTRAVIOLET LIGHT
Author(s) -
WEBB S. J.,
MALWINSKA KRISTINA
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.tb05977.x
Subject(s) - relative humidity , dehydration , irradiation , ultraviolet light , humidity , mutant , biophysics , chemistry , microbiology and biotechnology , biology , biochemistry , photochemistry , physics , gene , nuclear physics , thermodynamics
— The effect of relative humidity on the survival and sensitivity to radiations of Streptococcus liquefaciens has been studied. The micro‐organism was found to be little affected by dehydration in aerosols and its sensitivity to the lethal action of 2537 Å light to be unaffected by changes in the relative humidity at which the cells were held during irradiation. The cells were more stable to the lethal action of 3200–4000 Å, however, when they were held at 70% relative humidity than at 50 or 30% relative humidity. Mutant cells unable to liquify gelatine were induced by semi‐dehydration at 50% relative humidity and their numbers were increased by concomitant irradiation with 3200–4000 Å light. This type of mutant was not observed when the cells were irradiated with 2537 Å light. Mutant cells which had a different response from that of the parent cell to the presence of oxygen in their growth medium were produced by both wavebands of light, but only when the cells were held at 50% relative humidity. It is proposed that semi‐dehydration stresses the cell membrane and damages those parts of the bacterial DNA associated with the membrane. Concomitant irradiation is suggested to enhance this particular effect.