caa a22 4500 44588939X CHVBK 20180317145611.0 cr unu---uuuuu 170323e20110901xx s 000 0 eng 10.1007/s11120-011-9639-z doi (NATIONALLICENCE)springer-10.1007/s11120-011-9639-z Evidence for the occurrence of photorespiration in synurophyte algae [Elektronische Daten] [Shabana Bhatti, Brian Colman] The fluxes of CO2 and oxygen during photosynthesis by cell suspensions of Tessellaria volvocina and Mallomonas papillosa were monitored mass spectrometrically. There was no rapid uptake of CO2, only a slow drawdown to compensation concentrations of 26μM for T. volvocina and 18μM for M. papillosa, when O2 evolution ceased, indicating a lack of active bicarbonate uptake by the cells. Darkening of the cells after a period of photosynthesis did not cause rapid release of CO2, indicating the absence of an intracellular inorganic carbon pool. However, upon darkening a brief burst of CO2 was observed similar to the post-illumination burst characteristic of C3 higher plants. Treatment of the cells of both species with the membrane-permeable carbonic anhydrase inhibitor ethoxyzolamide had no adverse effect on photosynthetic rate, but stimulated the dark CO2 burst indicating the dark oxidation of a compound formed in the light. In the absence of any active accumulation of inorganic carbon photosynthesis in these species should be inhibited by O2. This was investigated in four synurophyte species T. volvocina, M. papillosa, Synura petersenii, and Synura uvella: photosynthetic O2 evolution rates in all four algae, measured by O2 electrode, were significantly higher (40-50%) in media at low O2 (4%) than in air-equilibrated (21% O2) media, indicating an O2 inhibition of photosynthesis (Warburg effect) and thus the occurrence of photorespiration in these species. Springer Science+Business Media B.V., 2011 Carbon concentrating mechanism nationallicence Chrysophyte nationallicence Mallomonas nationallicence Mass spectrometry nationallicence Photosynthesis nationallicence Photorespiration nationallicence Synura nationallicence Tessellaria nationallicence Bhatti Shabana Department of Biology, York University, M3J 1P3, Toronto, ON, Canada aut Colman Brian Department of Biology, York University, M3J 1P3, Toronto, ON, Canada aut Photosynthesis Research Springer Netherlands 109/1-3(2011-09-01), 251-256 0166-8595 109:1-3<251 2011 109 11120 https://doi.org/10.1007/s11120-011-9639-z text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11120-011-9639-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Bhatti Shabana Department of Biology, York University, M3J 1P3, Toronto, ON, Canada aut NATIONALLICENCE 700 1- Colman Brian Department of Biology, York University, M3J 1P3, Toronto, ON, Canada aut NATIONALLICENCE 773 0- Photosynthesis Research Springer Netherlands 109/1-3(2011-09-01), 251-256 0166-8595 109:1-3<251 2011 109 11120 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer