Effects of chloramphenicol on photosynthesis, protein profiles and transketolase activity under extremely high CO2 concentration in an extremely-high-CO2-tolerant green microalga, Chlorococcum littorale.
An extremely-high-CO2-tolerant alga, Chlorococcum littorale, showed high quantum efficiency of PSII (PhiII) in the light at 40% CO2, as well as at 5% CO2. However, PhiII decreased greatly when chloramphenicol (CAP) was added at 40% CO2, while no such decrease was observed at 5% CO2. Cycloheximide showed no effect on PhiII at either 5% or 40% CO2. The amount of a 76 kDa polypeptide (p76) on SDS-PAGE decreased markedly in the presence of CAP at 40% CO2 but not at 5% CO2. A partial amino acid sequence of p76 was 71-100% identical (10-14 identical residues out of 14 amino acids determined) to those of transketolases (TKLs) reported in higher plants and a cyanobacterium. In agreement with these observations, the TKL activity in C. littorale was decreased by CAP at 40% CO2, but not at 5% CO2. The transient decrease in TKL activity caused by CAP under 40% CO2 was well correlated with that in PhiII. These results indicate that the addition of CAP directly or indirectly influences the stability of TKL in C. littorale at 40% CO2, but not at 5% CO2, and that photosynthetic activity was reduced by a decrease in TKL activity.
Satoh
Akira
A
Marine Biotechnology Institute, 3-75-1Heita, Kamaishi, Iwate, 026-0001 Japan. akira.satoh@mbio.jp
Kurano
Norihide
N
Harayama
Shigeaki
S
Miyachi
Shigetoh
S
D000064:Acclimatization / Q000502:physiology; D020418:Algal Proteins / Q000187:drug effects* / Q000378:metabolism; D000595:Amino Acid Sequence / Q000502:physiology; D002245:Carbon Dioxide / Q000378:metabolism*; D002701:Chloramphenicol / Q000494:pharmacology*; D000460:Chlorophyta / Q000187:drug effects* / Q000378:metabolism; D010455:Peptides / Q000378:metabolism / Q000494:pharmacology; D010788:Photosynthesis / Q000187:drug effects* / Q000502:physiology; D045332:Photosystem II Protein Complex / Q000187:drug effects / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D014174:Transketolase / Q000187:drug effects* / Q000378:metabolism
D020418:Algal Proteins; D010455:Peptides; D045332:Photosystem II Protein Complex; D011500:Protein Synthesis Inhibitors; D002245:Carbon Dioxide; D002701:Chloramphenicol; D014174:Transketolase