Uptake of CO(2) and bicarbonate by intact cells and chloroplasts of Tetraedron minimum and Chlamydomonas noctigama.

Using a mass-spectrometric disequilibrium technique, net uptake of HCO(3)(-) and CO(2) during steady-state photosynthesis was studied in whole cells and chloroplasts from the green algae Tetraedron minimum and Chlamydomonas noctigama, grown in air enriched with 5% (v/v) CO(2) (high-CO(2) cells) or in air [0.035% (v/v) CO(2); low-CO(2) cells]. High- and low-CO(2) cells of both species were able to take up CO(2) and HCO(3)(-), with maximum rates being largely unaffected by the growth conditions.

Analysis of Chlamydomonas mutants with abnormal expression of CO2 and HCO3- uptake systems.

Eukaryotic microalgae such as Chlamydomonas reinhardtii possess an inducible CO2 concentrating mechanism that operates as a very close interaction between pyrenoid-based Rubisco, various carbonic anhydrases (CAs), and inorganic carbon (Ci) transport systems. While external and internal CAs have been characterised to the molecular level, the biochemistry and molecular biology of Ci uptake mechanisms have not been elucidated. Both Ci species, CO2 and HCO3, are taken up by the cells and chloroplasts during steady-state photosynthesis.

A possible role for carbonic anhydrase in the lumen of chloroplast thylakoids in green algae.

In order to understand the function of the lumen carbonic anhydrase (CA) which is bound to PSII at the lumenal side of the thylakoids in chloroplasts of eukaryotic algae, thylakoids were isolated from chloroplasts of Tetraedron minimum, Chlamydomonas noctigama, the cell wall-less mutant Chlamydomonas reinhardtii CW15, and a C. reinhardtii CW15/CIA3 mutant which lacks the lumen CA. The isolated thylakoids produced O2 on illumination and exhibited electron flow between PSII and PSI, indicating that the thylakoids were intact and the photosynthetic apparatus were functional.

Identification and localization of a thylakoid-bound carbonic anhydrase from the green algae Tetraedron minimum (Chlorophyta) and Chlamydomonas noctigama (Chlorophyta).

In order to broaden our understanding of the eukaryotic CO2-concentrating mechanism the occurrence and localization of a thylakoid-associated carbonic anhydrase (EC 4.2.1.

Purification of the Fusicoccin-Binding Protein from Oat Root Plasma Membrane by Affinity Chromatography with Biotinylated Fusicoccin.

Fusicoccin (FC), a fungal phytotoxin, evokes a number of physiological responses after binding to the FC-binding protein (FCBP). For characterization of this plasma membrane protein and elucidation of the signal transduction pathway, we purified active FCBP from oat (Avena sativa L. cv Valiant) root plasma membranes using avidin-biotin affinity chromatography.