Conformational changes of the submicroscopic chloroplast structure and physiological activity of Chlamydobotrys stellata

Relation between the Light-Harvesting Chlorophyll a-Protein Complex LHCPa and Photosystem I in the Alga Chlamydobotrys stellata

“…The photosynthetic apparatus of C. stellata thus might be at a higher evolutionary stage than that of the other algae species. The ability of this organism to alter its thylakoid composition (8) and structure (25,26) together with the photosynthetic functions (16) in response to changes of the environment corresponds with the flexibility of higher plant chloroplasts (1). Because of the dynamic nature of the fluid lipid matrix of the chloroplast thylakoids (1), the loss of PSII activity (16) as well as the decrease of LHCPb (8) and the increase of unstacking (26) and of CPI-related LHCPa (8) in photoheterotrophic C. stellata are of special interest.…”

“…when CO2 is replaced by acetate as carbon source for growth in the light, only PSI activity is necessary for acetate photoassimilation (10,23). This leads to changes in PSII activity (15,16), almost grana-free chloroplasts (25,26), and to a decrease in the PSII-dependent electron transport to PSI (27). Furthermore, phototrophic acetate nutrition induces an increase in the amount of Chl-protein complex LHCPa2 containing Chl a only (8).…”

Induction of the De Novo Formation of the Photosystem I-Related Light-Harvesting Chlorophyll Protein Complex LHCPa by Photoheterotrophic Nutrition

“…When CO2 is replaced by acetate as carbon source for growth in light, only PSI activity is necessary for acetate photoassimilation (7,13). This leads to a change in PSII activity (10,1), almost grana-free chloroplasts (15,16), and to a decrease in the PSII-dependent electron transport to PSI (17). Furthermore, phototrophic acetate nutrition induces an increase in the amount of the Chl protein complex LHCPa2, which is related to PSI (6) and contains Chl a only (5).…”

Photosystem II Activity in Agranal Bundle Sheath Chloroplasts from Zea mays

“…However, when the alga was grown photoheterotrophically on acetate, nearly all the chloroplast lamellae were separated from each other and the chloroplasts lacked photosystem II activity (16,17). Both photosystem II activity and appression of lamellae were regained when photoautotrophic growth was resumed, again indicating that appressed lamellae are necessary for photosystem II activity (16)(17)(18).In contrast, photosystem II activity is present in a mutant of C. reinhardi (ac-31) which has chloroplasts that contain only unappressed lamellae (8). Algae belonging to the Rhodophyta and Cyanophyta do not contain appressed lamellae yet evolve oxygen in the light.…”

“…The chloroplasts of the green alga Chlamydobotrys stellata contain appressed lamellae and carry out normal photosynthesis when grown photoautotrophically. However, when the alga was grown photoheterotrophically on acetate, nearly all the chloroplast lamellae were separated from each other and the chloroplasts lacked photosystem II activity (16,17). Both photosystem II activity and appression of lamellae were regained when photoautotrophic growth was resumed, again indicating that appressed lamellae are necessary for photosystem II activity (16)(17)(18).…”