title: Analysis of triacylglycerol accumulation under nitrogen deprivation in the red alga Cyanidioschyzon merolae.
abstract: Triacylglycerol (TAG) produced by microalgae is a potential source of biofuel. Although various metabolic pathways in TAG synthesis have been identified in land plants, the pathway of TAG synthesis in microalgae remains to be clarified. The unicellular rhodophyte Cyanidioschyzon merolae has unique properties as a producer of biofuel because of easy culture and feasibility of genetic engineering. Additionally, it is useful in the investigation of the pathway of TAG synthesis, because all of the nuclear, mitochondrial and plastid genomes have been completely sequenced. We found that this alga accumulated TAG under nitrogen deprivation. Curiously, the amount and composition of plastid membrane lipids did not change significantly, whereas the amount of endoplasmic reticulum (ER) lipids increased with considerable changes in fatty acid composition. The nitrogen deprivation did not decrease photosynthetic oxygen evolution per chlorophyll significantly, while phycobilisomes were degraded preferentially. These results suggest that the synthesis of fatty acids is maintained in the plastid, which is used for the synthesis of TAG in the ER. The accumulated TAG contained mainly 18 : 2(9,12) at the C-2 position, which could be derived from phosphatidylcholine, which also contains this acid at the C-2 position.
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Science, The University of Tokyo,Tokyo,Japan.|Core Research for Evolutional Science and Technology, Japan Science and Technology Agency,Tokyo,Japan.
authors.forename: Masakazu
authors.initials: M
authors.lastname: Toyoshima
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Science, The University of Tokyo,Tokyo,Japan.|Core Research for Evolutional Science and Technology, Japan Science and Technology Agency,Tokyo,Japan.
authors.forename: Natsumi
authors.initials: N
authors.lastname: Mori
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Science, The University of Tokyo,Tokyo,Japan.|Core Research for Evolutional Science and Technology, Japan Science and Technology Agency,Tokyo,Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Moriyama
authors.affiliation: Core Research for Evolutional Science and Technology, Japan Science and Technology Agency,Tokyo,Japan.|Department of Biological Science and Chemistry, Faculty of Science, Graduate School of Medicine, Yamaguchi University,Yamaguchi,Japan.
authors.forename: Osami
authors.initials: O
authors.lastname: Misumi
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Science, The University of Tokyo,Tokyo,Japan.|Core Research for Evolutional Science and Technology, Japan Science and Technology Agency,Tokyo,Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Sato
mesh_terms: D056804:Biofuels; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005227:Fatty Acids / Q000096:biosynthesis; D008563:Membrane Lipids / Q000032:analysis; D009584:Nitrogen / Q000172:deficiency*; D010713:Phosphatidylcholines / Q000737:chemistry; D045524:Phycobilisomes / Q000378:metabolism; D000461:Rhodophyta / Q000254:growth & development* / Q000378:metabolism* / Q000648:ultrastructure; D014280:Triglycerides / Q000378:metabolism*
chemical_list: D056804:Biofuels; D005227:Fatty Acids; D008563:Membrane Lipids; D010713:Phosphatidylcholines; D045524:Phycobilisomes; D014280:Triglycerides; D009584:Nitrogen