Differentiation of the photosynthetic apparatus of Chromatium vinosum, strain D.

Spectral changes in the near infrared absorption region of chromatophores of Chromatium vinosum, strain D, were analyzed. Spectral changes dependent in growing cultures on temperature (33° C and 39° C, respectively) were compared to artificial changes which take place under the influence of the detergent Triton X-100. Like addition of Triton X-100 to chromatophores, transfer of cells from 39° C to 33° C leads to the reversible formation of an absorption band at 820 nm at the expense of a band at 850 nm. But in contrast to the influence of Triton X-100, chromatophores isolated from cells grown at 39° C (39° C chromatophores), contain on an identical bacteriochlorophyll basis, higher amounts of pigment absorbing at 880 nm and lower amounts of pigment absorbing at 800 nm than found in 33° C chromatophores. Triton X-100 treatment does not influence the production of light induced absorbance changes characteristic of photochemical reaction centers; it does, however, change absorption spectra of a subchromatophore fraction which does not exhibit the known light dependent reaction center responses. The spectral properties of this fraction are altered with Triton X-100 in a manner comparable to whole chromatophores, i.e. translocation of the 850 nm band to 820 nm. Subchromatophore fractions isolated from 33° C chromatophores, which display an absorption band at 820 nm show in the presence of menadione a light induced absorbance change at 835 nm. Subchromatophore fractions from 39° C chromatophores, which display no absorbance at 820 nm show a light induced adsorbance change at 835 nm only after addition of Triton X-100. Spectral changes in growing cultures are accompanied by changes in the fluorescence emission spectra of isolated chromatophores. While 33° C chromatophores exhibit a major fluorescence emission band at 929 nm plus a minor band at 890 nm 39° C chromatophores exhibit only one band at 937 nm. [ABSTRACT FROM AUTHOR]