Mus Florence, Dubini Alexandra, Seibert Michael, Posewitz Matthew C, Grossman Arthur R
Department of Plant Biology, Carnegie Institution, Stanford, California 94305, USA.
J Biol Chem. 2007 Aug 31;282(35):25475-86. doi: 10.1074/jbc.M701415200. Epub 2007 Jun 12.
Both prokaryotic and eukaryotic photosynthetic microbes experience conditions of anoxia, especially during the night when photosynthetic activity ceases. In Chlamydomonas reinhardtii, dark anoxia is characterized by the activation of an extensive set of fermentation pathways that act in concert to provide cellular energy, while limiting the accumulation of potentially toxic fermentative products. Metabolite analyses, quantitative PCR, and high density Chlamydomonas DNA microarrays were used to monitor changes in metabolite accumulation and gene expression during acclimation of the cells to anoxia. Elevated levels of transcripts encoding proteins associated with the production of H2, organic acids, and ethanol were observed in congruence with the accumulation of fermentation products. The levels of over 500 transcripts increased significantly during acclimation of the cells to anoxic conditions. Among these were transcripts encoding transcription/translation regulators, prolyl hydroxylases, hybrid cluster proteins, proteases, transhydrogenase, catalase, and several putative proteins of unknown function. Overall, this study uses metabolite, genomic, and transcriptome data to provide genome-wide insights into the regulation of the complex metabolic networks utilized by Chlamydomonas under the anaerobic conditions associated with H2 production.
原核和真核光合微生物都会经历缺氧状态，尤其是在夜间光合活动停止的时候。在莱茵衣藻中，黑暗缺氧的特征是一系列广泛的发酵途径被激活，这些途径协同作用以提供细胞能量，同时限制潜在有毒发酵产物的积累。代谢物分析、定量PCR和高密度莱茵衣藻DNA微阵列被用于监测细胞适应缺氧过程中代谢物积累和基因表达的变化。观察到与氢气、有机酸和乙醇产生相关的蛋白质编码转录本水平升高，这与发酵产物的积累相一致。在细胞适应缺氧条件的过程中，超过500个转录本的水平显著增加。其中包括编码转录/翻译调节因子、脯氨酰羟化酶、混合簇蛋白、蛋白酶、转氢酶、过氧化氢酶以及几种功能未知的假定蛋白质的转录本。总体而言，本研究利用代谢物、基因组和转录组数据，对莱茵衣藻在与氢气产生相关的厌氧条件下所利用的复杂代谢网络的调控进行全基因组层面的洞察。
