Changes in carboxysome structure and grouping and in photosynthetic affinity for inorganic carbon in Anabaena strain PCC 7119 (Cyanophyta) in response to modification of CO2 and Na+ supply.
In ANABAENA: PCC 7119 a 4-fold decrease in the value of the apparent photosynthetic affinity for external inorganic carbon [K1/2 (Ci)] occurred between 9 and 12 h after the transfer from high-CO2 (2% CO2-enriched air) to air-growing conditions. A slight increase in carboxysome frequency occurred, but during this transition their appearance and distribution remained unchanged. ANABAENA: PCC 7119 did not improve its K1/2 (Ci) beyond the above cited level of acclimation neither by culturing the cyanobacteria in Na+-deficient medium in air nor by aeration with CO2-depleted air. In air-grown cultures, Na+ deficiency induced a large increase in carboxysome frequency and an alteration of their appearance: the greatest proportion were electron-dense whereas this type constituted a minority in high-CO2 and in air, Na+-sufficient conditions. It also induced major changes in carboxysome distribution, whereby more than 60% were grouped, compared with only 10% in high-CO2 and in air, Na+-sufficient conditions. These changes in carboxysome expression were extremely rapid, occurring mainly during the first 2 h.
Orús
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MI
Departamento de Biología, Universidad Autónoma de Madrid, E-28049 Madrid, Spain.
Rodríguez-Buey
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ML
Marco
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Fernández-Valiente
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D017033:Anabaena / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D002244:Carbon / Q000378:metabolism*; D002245:Carbon Dioxide / Q000494:pharmacology*; D002478:Cells, Cultured; D008854:Microscopy, Electron; D015388:Organelles / Q000378:metabolism* / Q000648:ultrastructure; D010788:Photosynthesis / Q000187:drug effects; D012273:Ribulose-Bisphosphate Carboxylase / Q000032:analysis / Q000378:metabolism; D012964:Sodium / Q000494:pharmacology*; D013997:Time Factors
D002245:Carbon Dioxide; D002244:Carbon; D012964:Sodium; D012273:Ribulose-Bisphosphate Carboxylase