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TRANSFER OF ENERGY FROM REACTION CENTER TO LIGHT HARVESTING CHLOROPHYLL IN A PHOTOSYNTHETIC BACTERIUM *
Author(s) -
Zankel Kenneth L.
Publication year - 1969
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.1751-1097.1969.tb05689.x
Subject(s) - photosynthetic reaction centre , fluorescence , purple bacteria , photochemistry , chlorophyll fluorescence , photosynthesis , bacteriochlorophyll , action spectrum , strain (injury) , absorption (acoustics) , chlorophyll , chemistry , dcmu , photosystem , electron transfer , analytical chemistry (journal) , photosystem ii , biology , physics , optics , biochemistry , environmental chemistry , organic chemistry , anatomy
— Previous evidence indicates that energy transfer in photosynthetic bacteria can occur from reaction center to light harvesting chlorophyll (the reverse of the usually considered flow) and that the amount of this flow depends on the strain of bacteria. The present report demonstrates that the action spectrum for fluorescence of Rhodopseudomonas spheroides , strain R26, is changed by adding the strong reductant dithionite. This change indicates that the amount of reverse flow can be altered chemically. The amount of reverse flow inferred from these measurements is consistent with the amount predicted from the absorption and fluorescence spectra of chromatophores and isolated reaction centers, and from the relative fluorescence yields of these two. The measurements permit an estimate of the transfer rates describing the energy flow from light harvesting to reaction center chlorophyll as well as the reverse flow. The spectrum for delayed fluorescence of Rps. spheroides , strain Ga, was found to be similar to that of the variable part of the fluorescence. This is a necessary, but not sufficient, condition that the energy for delayed fluorescence originates in the reaction centers.