Analysis of the effect of L-carnitine supplementation on global expression of Sachharomyces cerevisiae cultures

Microarray analysis of the effect of L-carnitine supplementation on global expression of Sachharomyces cerevisiae cultures in logarithmic growing conditions and after exposure to H2O2 induced oxidative stress.L-Carnitine plays a well documented role in eukaryotic energy homeostasis by acting as a shuttling molecule for activated acyl residues across intracellular membranes. This activity is supported by carnitine acyl-transferases and transporters, and is referred to as the carnitine shuttle. However, several pleiotropic and often beneficial effects of carnitine in humans have been reported that appear to be unrelated to the shuttling activity, but little conclusive evidence regarding the molecular networks that would be affected by carnitine exist. We have recently demonstrated a protective role of carnitine in oxidative stress in yeast that is independent of the carnitine shuttle. A DNA microarray-based global gene expression analysis identified Cyc3p, a cytochrome c heme lyase, as being important for carnitine's protective impact in oxidative stress conditions. These findings establish a direct genetic link to a carnitine-related phenotype that is independent of the shuttle system. The data suggest that the yeast Saccharomyces cerevisiae should provide a useful model for further elucidation of carnitine's physiological roles.Yeast cultures was grown to mid-log phase with and without carnitine supplementation to a final concentration of 100 mg/L. A second set was grown to mid log phase, with and without carnitine supplementation and exposed to 0.4 mM H2O2 for 30 min. The experiments were performed using biological duplicate.

本研究旨在分析L-肉碱补充剂对对数生长期内酵母菌Sachharomyces cerevisiae全基因组表达的影响，以及其在暴露于H2O2诱导的氧化应激后的影响。L-肉碱在真核生物能量稳态中发挥着重要作用，其作为活性酰基残基在细胞内膜间的转运分子，其作用已得到充分文献记载。这一作用得到肉碱酰基转移酶和转运蛋白的支持，并被称作肉碱转运机制。然而，关于肉碱在人体中表现出多种多样且通常有益的效应，尽管这些效应似乎与转运功能无关，但关于肉碱影响下的分子网络却缺乏确凿的证据。我们最近证明，L-肉碱在酵母菌中的保护作用独立于肉碱转运机制。基于DNA微阵列的全基因组表达分析识别了Cyc3p，一种细胞色素c血红素裂解酶，其在氧化应激条件下对肉碱保护作用的发挥至关重要。这些发现建立了与肉碱相关表型之间的直接遗传联系，该表型独立于转运系统。数据表明，酵母菌Saccharomyces cerevisiae可作为进一步阐明肉碱生理作用的理想模型。实验中，酵母菌培养至对数中期，在有或无肉碱补充剂的情况下，最终浓度达到100 mg/L。另一组培养至对数中期，在有或无肉碱补充剂的情况下，并暴露于0.4 mM H2O2中30分钟。实验采用生物重复进行。