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AN ACTION SPECTRUM FOR BLUE AND NEAR ULTRAVIOLET IN ACTIVATION OF Propionibacterium acnes; WITH EMPHASIS ON A POSSIBLE PORPHYRIN PHOTOSENSITIZATION
Author(s) -
Kjeldstad Berit,
Johnsson Anders
Publication year - 1986
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.1751-1097.1986.tb05592.x
Subject(s) - porphyrin , propionibacterium acnes , photochemistry , chemistry , irradiation , absorption (acoustics) , action spectrum , wavelength , monochromatic color , ultraviolet , photosensitizer , bacteria , materials science , optoelectronics , optics , biology , genetics , physics , nuclear physics , composite material
— Propionibacterium acnes (P. acnes ), grown on Eagles medium with different pH. were irradiated with monochromatic light in the range 320 to 440 nm. Different pH leads to different porphyrin concentrations in the cells. The light sensitivity of the bacteria was estimated from the reduction in their ability to form colonies after radiation. The sensitivity was highest for the lowest wavelength (320 nm). and decreased continuously with increasing wavelength up to 380 nm. In the region between 380 and 440 nm there was a second maximum (at 415 nm) which corresponds to the maximum absorption ol the fluorescing porphyrins in P. acnes . The sensitivity to 415 nm light was found to be dependent on the endogenous porphyrin concentration in the cells. while the sensitivity to 320 nm radiation was independent of the amount of porphyrin present. These results indicate that porphyrins produced by the bacteria are important for the light sensitivity of these bacteria.