title: Metabolic and morphological changes of an oil accumulating trebouxiophycean alga in nitrogen-deficient conditions.
abstract: Oil-rich algae have promising potential for a next-generation biofuel feedstock.Pseudochoricystis ellipsoideaMBIC 11204, a novel unicellular green algal strain, accumulates a large amount of oil (lipids) in nitrogen-deficient (-N) conditions. Although the oil bodies are easily visualized by lipophilic staining in the cells, little is known about how oil bodies are metabolically synthesized. Clarifying the metabolic profiles in -N conditions is important to understand the physiological mechanisms of lipid accumulations and will be useful to optimize culture conditions efficiently produce industrial oil. Metabolome and lipidome profiles were obtained, respectively, using capillary electrophoresis- and liquid chromatography-mass spectrometry fromP. ellipsoideain both nitrogen-rich (+N; rapid growth) and -N conditions. Relative quantities of more than 300 metabolites were systematically compared between these two conditions. Amino acids in nitrogen assimilation and N-transporting metabolisms were decreased to 1/20 the amount, or less, in -N conditions. In lipid metabolism, the quantities of neutral lipids increased greatly in -N conditions; however, quantities of nearly all the other lipids either decreased or only changed slightly. The morphological changes in +N and -N conditions were also provided by microscopy, and we discuss their relationship to the metabolic changes. This is the first approach to understand the novel algal strain's metabolism using a combination of wide-scale metabolome analysis and morphological analysis.
authors: Institute for Advanced Biosciences, Keio University, Tsuruoka, 997-0052 Yamagata Japan ; Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, 252-8520 Japan ; PRESTO, Japan Science and Technology Agency, Kawaguchi, 332-0012 Japan.
authors: Takuro
authors: T
authors: Ito
authors: Miho
authors: M
authors: Tanaka
authors: Haruka
authors: H
authors: Shinkawa
authors: Takashi
authors: T
authors: Nakada
authors: Yoshitaka
authors: Y
authors: Ano
authors: Norihide
authors: N
authors: Kurano
authors: Tomoyoshi
authors: T
authors: Soga
authors: Masaru
authors: M
authors: Tomita
keywords: Capillary electrophoresis; Liquid chromatography; Mass spectrometry; Metabolic profile; Oil-rich algae