Comparative transcriptome analysis of responses of Methanothermobacter thermautotrophicus to different environmental stimuli
Comparative transcriptome analysis of responses of Methanothermobacter thermautotrophicus to different environmental stimuli
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DOI：
10.1111/j.1462-2920.2007.01508.x
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发表时间：
2008-04-01
影响因子：
5.1
通讯作者：
Watanabe, Kazuya
中科院分区：
文献类型：
--
作者：
Kato, Souichiro;Kosaka, Tomoyuki;Watanabe, Kazuya
嗜热甲烷热杆菌Delta H菌株是一种典型的氢营养型产甲烷菌，其完整的基因组序列和广泛的生化信息是可用的。然而，人们对这种生物体如何调节其细胞功能以应对环境刺激知之甚少。本研究构建了M.热自养型和用于获得洞察这种生物体如何响应不同的环境刺激，包括氢消耗，pH值和温度的变化和有毒物质（过氧化氢和氨）的发生。我们的分析证实了产甲烷基因（包括mtd，mer，frh和mcr）在氢限制条件下表达上调，而其中一些基因受到其他环境刺激的影响。关于这种生物的应激反应，揭示了几个独特的功能。首先，在这种生物体中没有普遍的压力反应。第二，基因的替代氧化还原酶，如赤藓红，上调氧化应激下，但那些典型的抗氧化酶。第三，与细胞表面结构修饰相关的基因在胁迫条件下差异表达。最后，需要能量的CO2同化系统在胁迫条件下下调。这些结果表明M.嗜热自养菌具有复杂的转录调节机制，这有助于其在不稳定的生态系统如厌氧消化器中存活。
Methanothermobacter thermautotrophicus strain Delta H is a model hydrogenotrophic methanogen, for which the complete genome sequence and extensive biochemical information are available. Little is known, however, about how this organism regulates its cellular functions in response to environmental stimuli. In this study, whole-genome oligonucleotide microarrays were constructed for M. thermautotrophicus and used to gain insights into how this organism responds to different environmental stimuli, including hydrogen depletion, shifts in pH and temperature and the occurrence of toxics (hydrogen peroxide and ammonia). Our analysis confirmed that methanogenesis genes (including mtd, mer, frh and mcr) were upregulated under hydrogen-limited conditions, while some of them were affected by other environmental stimuli. Concerning stress responses of this organism, several unique features were revealed. First, there was no universal stress response in this organism. Second, genes for alternative redox enzymes, such as rubrerythrin, were upregulated under the oxidative stress, but those for typical antioxidant enzymes were not. Third, genes relevant to the modification of cell surface structures were differentially expressed under stress conditions. Finally, energy-requiring CO2 assimilation systems were downregulated under stress conditions. These findings suggest that M. thermautotrophicus has complex transcriptional regulation mechanisms that facilitate it to survive in unstable ecosystems such as an anaerobic digester.