Barros de Souza Rafael, Silva Rayssa Karla, Ferreira Dayvison Soares, de Sá Leitão Paiva Junior Sérgio, de Barros Pita Will, de Morais Junior Marcos Antonio
Interdepartmental Research Group in Metabolic Engineering, Federal University of Pernambuco, Avenida Moraes Rego, No. 1235, Recife, PE 50760-901, Brazil.
Laboratory of Bioinformatics and Evolutionary Biology, Federal Rural University Pernambuco. Rua Dom Manoel de Medeiros, s/n, Recife, PE 52171-900, Brazil.
Metallomics. 2016 Nov 9;8(11):1193-1203. doi: 10.1039/c6mt00157b.
In a recent work we showed that magnesium (Mg) plays an important role in industrial ethanol production, overcoming the negative effect of the excess of minerals, particularly copper, present in sugarcane juice, with a consequent increase in ethanol yield. This cation has been reported to be involved in several steps of yeast metabolism, acting mainly as a co-factor of several enzymes of fermentation metabolism and protecting yeast cells from stressful conditions. However, despite many physiological investigations, its effect in the molecular mechanisms that control such metabolic activities remains unclear and to date no information concerning its influence on gene expression has been provided. The present work took advantage of the DNA microarray technology to analyse the global gene expression in yeast cells upon fermentation in Mg-supplemented medium. The results of the fermentation parameters confirmed the previous report on the increase in ethanol yield by Mg. Moreover, the gene expression data revealed an unexpected set of up-regulated genes currently assigned as being negatively-regulated by glucose, which belong to respiratory and energy metabolism, the stress response and the glyoxalate cycle. On the other hand, genes involved in ribosome biogenesis were down-regulated. Computational analysis provided evidence for a regulatory network commanded by key transcriptional factors that may be responsible for the biological action of Mg in yeast cells. In this scenario, Mg seems to act by reprogramming the yeast metabolism by releasing many genes from glucose catabolite repression with positive consequences for ethanol production and maintenance of cell viability.
在最近的一项研究中，我们发现镁（Mg）在工业乙醇生产中起着重要作用，它能克服甘蔗汁中过量矿物质（尤其是铜）的负面影响，从而提高乙醇产量。据报道，这种阳离子参与酵母代谢的多个步骤，主要作为发酵代谢中几种酶的辅助因子，并保护酵母细胞免受应激条件的影响。然而，尽管进行了许多生理学研究，其在控制此类代谢活动的分子机制中的作用仍不清楚，迄今为止，尚未提供有关其对基因表达影响的任何信息。本研究利用DNA微阵列技术分析了在添加镁的培养基中发酵时酵母细胞的全局基因表达。发酵参数的结果证实了先前关于镁提高乙醇产量的报道。此外，基因表达数据揭示了一组意想不到的上调基因，这些基因目前被认为受葡萄糖负调控，它们属于呼吸和能量代谢、应激反应和乙醛酸循环。另一方面，参与核糖体生物合成的基因被下调。计算分析为一个由关键转录因子指挥的调控网络提供了证据，该网络可能负责镁在酵母细胞中的生物学作用。在这种情况下，镁似乎通过解除许多基因的葡萄糖分解代谢阻遏来重新编程酵母代谢，对乙醇生产和细胞活力的维持产生积极影响。
