Liu Hongwei, Zhao Xin, Wang Fangjun, Li Yonghong, Jiang Xining, Ye Mingliang, Zhao Zongbao K, Zou Hanfa
National Chromatography R&A Centre, Dalian Institute of Chemical Physics, CAS, Dalian 116023, People's Republic of China.
Yeast. 2009 Oct;26(10):553-66. doi: 10.1002/yea.1706.
Intracellular lipid accumulation is a common biological process for some eukaryotic microorganisms under specific growth conditions, yet study on this phenomenon at an '-omics' level remains rare. In this study we induced lipid accumulation by the oleaginous yeast Rhodosporidium toruloides by transferring cells into a nitrogen-limited medium and performed a comparative and semi-quantitative proteomic analysis of cell samples obtained thereafter by a 2D-LC-MS/MS approach. A total of 184 proteins were identified, based on the database of yeast Saccharomyces cerevisiae. Semi-quantitative analysis suggested that 46 proteins were notably changed during the lipid production process. Among them, seven, three and four proteins were significantly upregulated only at the late stage, the early stage and both stages, respectively. There were 26 proteins drastically downregulated at both stages. The majority of the downregulated proteins are related to protein metabolism and carbohydrate metabolism, whereas the upregulated proteins are mainly involved in alternative nitrogen sources metabolism and lipid biosynthesis. Our data indicated that a nitrogen deficiency environment had a key impact on cellular metabolism that likely stimulated the lipid accumulation process by R. toruloides. This work provids valuable information for further exploration of the molecular mechanism of cellular lipid metabolism and should be of great interest in oleaginous microorganisms engineering.
细胞内脂质积累是一些真核微生物在特定生长条件下常见的生物学过程，但在“组学”水平上对这一现象的研究仍然很少。在本研究中，我们通过将细胞转移到氮限制培养基中，诱导产油酵母红冬孢酵母积累脂质，并采用二维液相色谱-串联质谱法对随后获得的细胞样品进行了比较和半定量蛋白质组分析。基于酿酒酵母数据库，共鉴定出184种蛋白质。半定量分析表明，46种蛋白质在脂质产生过程中发生了显著变化。其中，分别有7种、3种和4种蛋白质仅在后期、早期和两个阶段均显著上调。两个阶段均有26种蛋白质大幅下调。下调的蛋白质大多与蛋白质代谢和碳水化合物代谢有关，而上调的蛋白质主要参与替代氮源代谢和脂质生物合成。我们的数据表明，氮缺乏环境对细胞代谢有关键影响，可能刺激了红冬孢酵母的脂质积累过程。这项工作为进一步探索细胞脂质代谢的分子机制提供了有价值的信息，对产油微生物工程具有重要意义。
