Abstract
Gloeobacter violaceus lacks thylakoid membranes and seems to be one of the earliest cyanobacterial species according to the recent genome analysis. The bacterium that may retain primitive features of oxygen revolving photosynthesis contains phycoerythrins (PE), phycocyanins (PC), allophycocyanins (APC) and chlorophyll a (Chl a). We cultured them under different light conditions and detected changes of antenna pigment contents and photosystems. As reported previously the organism does not seem to change the ratio of PE/PC contents (complementary chromatic adaptation; Rippka et al.;1974), but we detected change in color; G. violaceus grown under red light became reddish and under green light became bluish. Their absorption spectra showed little change in the PE/PC ratio but a large change in the (PE, PC)/Chl ratio. We compared pigment composition and PS I/II activities of differently colored cells by the analysis by a single cell microspectrometry, time-resolved fluorescence analysis at cryogenic temperature and delayed fluorescence.
