1995 Fiscal Year Final Research Report Summary

Research on the pyrenoid in Chlamydomonas

Research Project

Project/Area Number	05804047
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	植物生理
Research Institution	Tokyo University of Pharmacy and Life Science (1994-1995) The University of Tokyo (1993)
Principal Investigator	TSUZUKI Mikio Tokyo University of Pharmacy and Life Scinece, School of Life Science, Assistant Professor, 生命科学部, 教授 (70155430)
Project Period (FY)	1993 – 1995
Keywords	pyrenoid / carbon dioxide / microalgae / Chlamydomonas / Rubisco / starch
Research Abstract	The pyrenoid, which is located in chloroplast of algae, increases under low CO_2 conditions by about 3 times in Chlamydomonas. Sucrose density gradient centrifugation of the pyrenoid fixed with HgC1_2 showed relatively heavier pyrenoid in the cells adapted to low CO_2 condition. Average protein content of the pyrenoid showed the same result. During the adaptation to low CO_2 concentration where the pyrenoid developed, rbcS1, one of two genes of small subunit of Rubisco, was transcribed less than that in high CO_2 condition, while rbcS2, the other Rubisco gene, was at almost the same level. The development of the pyrenoid was still observed in the presence of chloramphenicol.