Cytoplasmic membrane vesicles isolated from the gram-negative photosynthetic bacterium Rhodobacter capsulatus catalyzed the transport of nucleotides. No transport occurred in the intact bacteria unless they were pretreated with EDTA. The transport rate was measured by incorporation of radioactive phosphate into externally added ADP or by incorporation of nonradioactive phosphate into added labe...

The accumulation of carbon storage compounds by many unicellular algae after nutrient deprivation occurs despite declines in their photosynthetic apparatus. To understand the regulation and roles of photosynthesis during this potentially bioenergetically valuable process, we analyzed photosynthetic structure and function after nitrogen deprivation in the model alga Chlamydomonas reinhardtii. Tr...

Membrane-exposed residues are more hydrophobic than buried interior residues in the transmembrane regions of the photosynthetic reaction center from Rhodobacter sphaeroides. This hydrophobic organization is opposite to that of water-soluble proteins. The relative polarities of interior and surface residues of membrane and water soluble proteins are not simply reversed, however. The hydrophobici...

We investigated the photosynthetic limitations occurring during dehydration and rehydration of Xerophyta humilis, a poikilochlorophyllous resurrection plant, and whether volatile and non-volatile isoprenoids might be involved in desiccation tolerance. Photosynthesis declined rapidly after dehydration below 85% relative water content (RWC). Raising intercellular CO(2) concentrations during desi...

A new type of membrane-bound cytochrome c was found in a marine purple photosynthetic bacterium, Rhodovulum sulfidophilum. This cytochrome c was significantly accumulated in cells growing under anaerobic photosynthetic conditions and showed an apparent molecular mass of approximately 100 kDa when purified and analyzed by SDS-PAGE. The midpoint potential of this cytochrome c was 369 mV. Flash-in...

Fine structure, pigment content and photosynthetic activity of variegated leaves of Euonymus fortunei var. radicans have been studied in detail. The middle dark-green leaf areas contain normal chloroplasts with large grana. Their chlorophyll content is high, as is their photosynthetic activity. The marginal leaf areas with mutant plastids are highly light-sensitive. When grown in the shade they...

In photosynthesis, the energy of the Sun is absorbed by the light-harvesting antenna and transferred to the reaction center (RC) within several tens of picoseconds. In the RC the solar energy is converted into electrochemical energy by means of a trans-membrane charge separation. Photosynthetic purple bacteria employ a single reaction center. In contrast, in photosynthesis of plants, algae and ...

Band 7 proteins, which encompass members of the stomatin, prohibitin, flotillin, and HflK/C protein families, are integral membrane proteins that play important physiological roles in eukaryotes but are poorly characterized in bacteria. We have studied the band 7 proteins encoded by the cyanobacterium Synechocystis sp. strain PCC 6803, with emphasis on their structure and proposed role in the a...

Flavonoids are natural polyphenolic compounds produced by many aquatic plants and released in their environments. In this study, the effects of several aquatic flavonoids on cyanobacterial Microcystis aeruginosa, especially in relation to the cell growth, photosynthetic activity, cell morphology, and cell membrane integrity, were investigated. Significant growth inhibition was observed when the...