Studies on the natural state of bacteriochlorophyll

Abstract

Aqueous extracts of the Thiorhodacea Chromatium strain D, and the Athiorhodaceae Rhodopseudomonas spheroides, Rhodospirillum ntolischianum and Rhodospirillum rubrura were disintegrated by supersonic vibration as well as, in two additional experiments, by detergent action. The 850 m/~ maximum of the Chromatium infrared absorption spectrum was reduced by aerobic supersonic disintegration. In nitrogen, this treatment did not induce any marked absorption changes. Except for Rhodopseudomonas, the fluorescence quantum yield of the bacteriochlorophyll type maximally absorbing at 89 ° m/~ was found to decrease when aerobic supersonic treatment was applied. This phenomenon proved to occur at irradiation with wavelengths predominantly absorbed by each of the bacteriochlorophyll types. With anaerobic vibration, no decrease of fluorescence was observed. Experiments on the influence of detergent action on the bacteriochlorophyll types suggested that fluorescence yield of the type maximally absorbing at 890 m/z was decreased progressively when irradiation occurred at wavelengths predominantly absorbed by the B89o, B85o, or B8oo bacteriochlorophyll type. The results are discussed. It is concluded that the applied supersonic disintegration procedure was unable to separate the bacteriochlorophyll types from each other with regard to their function. Indication was obtained that detergent action may be successful in this respect.