System Response of Metabolic Networks in Chlamydomonas reinhardtii to Total Available Ammonium
System Response of Metabolic Networks in Chlamydomonas reinhardtii to Total Available Ammonium
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DOI：
10.1074/mcp.m111.016733
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发表时间：
2012-10-01
影响因子：
7
通讯作者：
Fiehn, Oliver
中科院分区：
文献类型：
--
作者：
Lee, Do Yup;Park, Jeong-Jin;Fiehn, Oliver
已知大量营养素的急剧变化会导致光合细菌莱茵衣藻的生物化学和基因表达发生巨大变化。然而，代谢组学和蛋白质组学对微量营养素减少的反应尚未研究。与对照培养物相比，当铵水平降低25-100%时，在25%或50%的氮还原下28小时，铵吸收和生长速率不受影响。然而，初级代谢和酶表达在急性条件下（4小时和10小时后铵还原）与慢性条件下（18小时和28小时的时间点）相比，表现出显着的变化。145个确定的代谢产物的响应进行了定量，使用气相色谱-飞行时间质谱法; 495蛋白质（包括187酶）进行了监测，使用液相色谱-离子阱质谱与无标记光谱计数。胁迫反应和碳同化过程（卡尔文循环，乙酸吸收和叶绿素生物合成）首先改变，除了增加酶的含量为脂质生物合成和积累的短链游离脂肪酸。发现氮/碳平衡代谢仅在慢性条件下改变，例如在柠檬酸循环和氨基酸代谢中。衣原体的代谢很容易响应总可用介质氮的时间增加短链游离脂肪酸和内部蛋白质的营业额，氮资源耗尽之前很久。Molecular & Cellular Proteomics 11：10.1074/mcp. M111.016733，973-988，2012.
Drastic alterations in macronutrients are known to cause large changes in biochemistry and gene expression in the photosynthetic alga Chlamydomonas reinhardtii. However, metabolomic and proteomic responses to subtle reductions in macronutrients have not yet been studied. When ammonium levels were reduced by 25-100% compared with control cultures, ammonium uptake and growth rates were not affected at 25% or 50% nitrogen-reduction for 28 h. However, primary metabolism and enzyme expression showed remarkable changes at acute conditions (4 h and 10 h after ammonium reduction) compared with chronic conditions (18 h and 28 h time points). Responses of 145 identified metabolites were quantified using gas chromatography-time of flight mass spectrometry; 495 proteins (including 187 enzymes) were monitored using liquid chromatography-ion trap mass spectrometry with label-free spectral counting. Stress response and carbon assimilation processes (Calvin cycle, acetate uptake and chlorophyll biosynthesis) were altered first, in addition to increase in enzyme contents for lipid biosynthesis and accumulation of short chain free fatty acids. Nitrogen/carbon balance metabolism was found changed only under chronic conditions, for example in the citric acid cycle and amino acid metabolism. Metabolism in Chlamydomonas readily responds to total available media nitrogen with temporal increases in short-chain free fatty acids and turnover of internal proteins, long before nitrogen resources are depleted. Molecular & Cellular Proteomics 11: 10.1074/mcp.M111.016733, 973-988, 2012.