caa a22 4500 445889616 CHVBK 20180317145611.0 cr unu---uuuuu 170323e20110901xx s 000 0 eng 10.1007/s11120-011-9663-z doi (NATIONALLICENCE)springer-10.1007/s11120-011-9663-z Physiological characterization and light response of the CO2-concentrating mechanism in the filamentous cyanobacterium Leptolyngbya sp. CPCC 696 [Elektronische Daten] [Elvin de Araujo, Jason Patel, Charlotte de Araujo, Susan Rogers, Steven Short, Douglas Campbell, George Espie] We studied the interactions of the CO2-concentrating mechanism and variable light in the filamentous cyanobacterium Leptolyngbya sp. CPCC 696 acclimated to low light (15μmolm−2s−1 PPFD) and low inorganic carbon (50μMCi). Mass spectrometric and polarographic analysis revealed that mediated CO2 uptake along with both active Na+-independent and Na+-dependent HCO3 − transport, likely through Na+/HCO3 − symport, were employed to concentrate Ci internally. Combined transport of CO2 and HCO3 − required about 30kJmol−1 of energy from photosynthetic electron transport to support an intracellular Ci accumulation 550-fold greater than the external Ci. Initially, Leptolyngbya rapidly induced oxygen evolution and Ci transport to reach 40-50% of maximum values by 50μmolm−2s−1 PPFD. Thereafter, photosynthesis and Ci transport increased gradually to saturation around 1,800μmolm−2s−1 PPFD. Leptolyngbya showed a low intrinsic susceptibility to photoinhibition of oxygen evolution up to PPFD of 3,000μmolm−2s−1. Intracellular Ci accumulation showed a lag under low light but then peaked at about 500 μmol photons m−2s−1 and remained high thereafter. Ci influx was accompanied by a simultaneous, light-dependent, outward flux of CO2 and by internal CO2/HCO3 − cycling. The high-affinity and high-capacity CCM of Leptolyngbya responded dynamically to fluctuating PPFD and used excitation energy in excess of the needs of CO2 fixation by increasing Ci transport, accumulation and Ci cycling. This capacity may allow Leptolyngbya to tolerate periodic exposure to excess high light by consuming electron equivalents and keeping PSII open. Springer Science+Business Media B.V., 2011 Ci pump/leak cycle nationallicence CO2-concentrating mechanism nationallicence CO2 uptake nationallicence Cyanobacteria nationallicence Leptolyngbya nationallicence Na+-dependent HCO3 − transport nationallicence Light response nationallicence Photoprotection nationallicence Photosynthesis nationallicence de Araujo Elvin Department of Biology, University of Toronto, 3359 Mississauga Road, L5L 1C6, Mississauga, ON, Canada aut Patel Jason Department of Biology, University of Toronto, 3359 Mississauga Road, L5L 1C6, Mississauga, ON, Canada aut de Araujo Charlotte Department of Cell and Systems Biology, University of Toronto, 3359 Mississauga Road, L5L 1C6, Mississauga, ON, Canada aut Rogers Susan Department of Biology, Mount Allison University, 63B York St., E4L 3G7, Sackville, NB, Canada aut Short Steven Department of Biology, University of Toronto, 3359 Mississauga Road, L5L 1C6, Mississauga, ON, Canada aut Campbell Douglas Department of Biology, Mount Allison University, 63B York St., E4L 3G7, Sackville, NB, Canada aut Espie George Department of Biology, University of Toronto, 3359 Mississauga Road, L5L 1C6, Mississauga, ON, Canada aut Photosynthesis Research Springer Netherlands 109/1-3(2011-09-01), 85-101 0166-8595 109:1-3<85 2011 109 11120 https://doi.org/10.1007/s11120-011-9663-z text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11120-011-9663-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- de Araujo Elvin Department of Biology, University of Toronto, 3359 Mississauga Road, L5L 1C6, Mississauga, ON, Canada aut NATIONALLICENCE 700 1- Patel Jason Department of Biology, University of Toronto, 3359 Mississauga Road, L5L 1C6, Mississauga, ON, Canada aut NATIONALLICENCE 700 1- de Araujo Charlotte Department of Cell and Systems Biology, University of Toronto, 3359 Mississauga Road, L5L 1C6, Mississauga, ON, Canada aut NATIONALLICENCE 700 1- Rogers Susan Department of Biology, Mount Allison University, 63B York St., E4L 3G7, Sackville, NB, Canada aut NATIONALLICENCE 700 1- Short Steven Department of Biology, University of Toronto, 3359 Mississauga Road, L5L 1C6, Mississauga, ON, Canada aut NATIONALLICENCE 700 1- Campbell Douglas Department of Biology, Mount Allison University, 63B York St., E4L 3G7, Sackville, NB, Canada aut NATIONALLICENCE 700 1- Espie George Department of Biology, University of Toronto, 3359 Mississauga Road, L5L 1C6, Mississauga, ON, Canada aut NATIONALLICENCE 773 0- Photosynthesis Research Springer Netherlands 109/1-3(2011-09-01), 85-101 0166-8595 109:1-3<85 2011 109 11120 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer