Differentiation of the photosynthetic apparatus of Chromatium vinosum, strain D

Abstract

The influence of light intensity and temperature on photoheterotrophically or photoautotrophically growing cultures of Chromatium vinosum, strain D, was investigated using the following parameters: growth, bacteriochlorophyll synthesis, cellular bacteriochlorophyll contents and near infra-red absorption spectra. Without regard of the respective light intensity cultures growing heterotrophically below 36.5°C exhibited an absorption spectrum characterized by a maximum at 800 nm with shoulders at 820, 850 and 880 nm. Also, without regard of light intensity cultures growing heterotrophically above 36.5°C exhibited an absorption spectrum characterized by a maximum at 850 nm with a shoulder at 880 nm and second peak at 800 nm. Under high light intensity (15000 Lux) and at 33°C autotrophic cultures formed a bacteriochlorophyll a spectrum resembling that of heterotrophic cultures growing above 36.5°C; in contrast at low light intensity (3000 Lux) and 33°C autotrophic cultures formed a spectral type resembling that of heterotrophic cultures growing below 36.5°C. Independent of temperature, heterotrophic cultures adjusted to identical specific bacteriochlorophyll contents at a given light intensity. Increasing light intensities increased the growth rate and, consequently, also the rate of bacteriochlorophyll synthesis as temperature increased. The data suggest a correlation between the growth rate and the rate of ATP regeneration. There is no conclusive evidence, however, that the growth rate is inevitably correlated with specific bacteriochlorophyll contents of cells or the fine structure of the near infra-red absorption spectra.