Department of Analytical Chemistry, University of Bochum, Bochum, Germany.
Proteomics. 2010 Feb;10(3):445-57. doi: 10.1002/pmic.200900482.
Corynebacterium glutamicum is one of the biotechnologically most important microorganisms because of its ability to enrich amino acids extracellularly. Hence, C. glutamicum requires effective adaptation strategies against both hypo- and hyperosmotic stress. We give a comprehensive and coherent outline about the quantitative dynamics of C. glutamicum during adaptation to hyperosmotic stress at the transcript and protein levels. The osmolyte carrier ProP, playing a pivotal role in hyperosmotic stress defence, exhibits the strongest up-regulation of all proteins. A conspicuously regulated group comprises proteins involved in lipid biosynthesis of the cell envelope. This is in accordance with our observation of a more viscous and stickier cell envelope, which is supported by the findings of an altered lipid composition. Together with our results, showing that several transporters were down-regulated, this membrane adaptation appears to be one of C. glutamicum's major protection strategies against hyperosmotic stress. In addition, we demonstrate that no oxidative stress and no iron limitation occur during salt stress contrary to former postulations. Ultimately, it is remarkable that various proteins with divergent mRNA-protein dynamics and regulation have been observed. This leads to the assumption that there are still unknown mechanisms in between the bacterial transcription, translation and post-translation and that these are waiting to be unravelled.
谷氨酸棒杆菌是生物技术中最重要的微生物之一，因为它能够在外源环境中富集氨基酸。因此，谷氨酸棒杆菌需要有效的适应策略来应对低渗和高渗应激。我们全面而连贯地概述了谷氨酸棒杆菌在转录和蛋白质水平适应高渗应激时的定量动态。渗透调节剂载体 ProP 在高渗应激防御中起着关键作用，其表达水平是所有蛋白质中上调最明显的。一个显著调控的蛋白群包括参与细胞膜脂生物合成的蛋白。这与我们观察到的更粘稠和更粘的细胞膜一致，这一发现得到了脂质组成改变的支持。与我们发现的一些转运蛋白下调的结果一致，这种膜适应性似乎是谷氨酸棒杆菌对抗高渗应激的主要保护策略之一。此外，我们还证明了在盐胁迫期间没有发生氧化应激和铁限制，这与以前的假设相反。最终，值得注意的是，观察到了各种具有不同 mRNA-蛋白质动态和调控的蛋白质。这使得人们假设，在细菌的转录、翻译和翻译后之间仍然存在未知的机制，这些机制有待揭示。
