Uptake of HCO3- and CO2 in cells and chloroplasts from the microalgae Chlamydomonas reinhardtii and Dunaliella tertiolecta

• Published in: Plant physiology (Bethesda) Vol. 116; no. 1; pp. 193 - 201
• Main Authors: Amoroso, G, Sultemeyer, D, Thyssen, C, Fock, H.P
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01.01.1998
• Subjects: ACCLIMATIZATION; ADAPTACION; ADAPTATION; Biological and medical sciences; CARBON DIOXIDE; CARBON DIOXIDE ENRICHMENT; CARBONATE; CARBONATES; CARBONATOS; Cell Biology and Signal Transduction; Cell growth; Cell membranes; CELLS; CELLULE; CELULAS; CHLAMYDOMONAS REINHARDTII; CHLOROPLASTE; CHLOROPLASTS; CLOROPLASTO; CRECIMIENTO; CROISSANCE; DIOXIDO DE CARBONO; DIOXYDE DE CARBONE; DOSAGE EFFECTS; DUNALIELLA TERTIOLECTA; EFECTOS DE DOSIFICACION; EFFET DOSE; ENRICHISSEMENT EN GAZ CARBONIQUE; ENRIQUECIMIENTO EN GAS CARBONICO; Evolution; FOTOSINTESIS; Fundamental and applied biological sciences. Psychology; GROWTH; ION; ION TRANSPORT; ION UPTAKE; IONES; IONS; Metabolism; PHOTOSYNTHESE; PHOTOSYNTHESIS; Photosynthesis, respiration. Anabolism, catabolism; Plant cells; Plant physiology and development; Plants; Plastids; Protoplasts; Induction; Algae; Chlorophycophyta; Carbon dioxide; Dunaliella tertiolecta; Hydrogencarbonates; Medium enrichment; Absorption; Membrane transport; Chlamydomonas reinhardtii; Kinetics; Chloroplast; Thallophyta
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.116.1.193

Mass-spectrometric disequilibrium analysis was applied to investigate CO2 uptake and HCO3- transport in cells and chloroplasts of the microalgae Dunaliella tertiolecta and Chlamydomonas reinhardtii, which were grown in air enriched with 5% (v/v) CO2 (high-Ci cells) or in ambient air (low-Ci cells). High- and low-Ci cells of both species had the capacity to transport CO2 and HCO3-, with maximum rates being largely unaffected by the growth conditions. In high- and low-Ci cells of D. tertiolecta, HCO3- was the dominant inorganic C species taken up, whereas HCO3- and CO2 were used at similar rates by C reinhardtii. The apparent affinities of HCO3- transport and CO2 uptake increased 3- to 9-fold in both species upon acclimation to air. Photosynthetically active chloroplasts isolated from both species were able to transport CO2 and HCO3-. For chloroplasts from C reinhardtii, the concentrations of HCO3- and CO2 required for half-maximal activity declined from 446 to 33 micromolar and 6.8 to 0.6 micromolar respectively, after acclimation of the parent cells to air; the corresponding values for chloroplasts from D. tertiolecta decreased from 203 to 58 micromolar and 5.8 to 0.5 micromolar, respectively. These results indicate the presence of inducible high-affinity HCO3- and CO2 transporters at the chloroplast envelope membrane