For osmoadaptation the halophilic bacterium Halomonas elongata synthesizes as its main compatible solute the aspartate derivative ectoine. H. elongata does not rely entirely on synthesis but can accumulate ectoine by uptake from the surrounding environment with the help of the osmoregulated transporter TeaABC. Disruption of the TeaABC-mediated ectoine uptake creates a strain that is constantly losing ectoine to the medium. However, the efflux mechanism of ectoine in H. elongata is not yet understood. H. elongata possesses four genes encoding mechanosensitive channels all of which belong to the small conductance type (MscS). Analysis by qRT-PCR revealed a reduction in transcription of the mscS genes with increasing salinity. The response of H. elongata to hypo- and hyperosmotic shock never resulted in up-regulation but rather in down-regulation of mscS transcription. Deletion of all four mscS genes created a mutant that was unable to cope with hypoosmotic shock. However, the knockout mutant grew significantly faster than the wildtype at high salinity of 2 M NaCl, and most importantly, still exported 80% of the ectoine compared to the wildtype. We thus conclude that a yet unknown system, which is independent of mechanosensitive channels, is the major export route for ectoine in H. elongata.

中文翻译：

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机械敏感通道对长形单胞菌渗透适应和植物素排泄的贡献。

为了进行渗透适应，嗜盐细菌长形嗜盐单胞菌（Halomonas elongata）合成了天冬氨酸衍生物ectoine作为其主要相容溶质。H.泡桐并不完全依赖于合成的，但可以通过吸收来自周围环境的osmoregulated转运TeaABC帮助积累四氢嘧啶。破坏TeaABC介导的植物素摄取会产生一种菌株，该菌株会不断将植物素流失到培养基中。然而，依克多因在外排机制H.泡桐尚不清楚。H.泡桐具有编码机械敏感性通道所有这些属于小电导型（MSCS）四种基因。通过qRT-PCR分析发现mscS的转录减少盐度增加的基因。响应H.泡桐到低血糖和高渗休克从未导致上调，而是在下调MSCS转录。所有四个mscS基因的删除创建了一个突变体，无法应对低渗性休克。但是，在2M NaCl高盐度下，敲除突变体的生长速度明显快于野生型，最重要的是，与野生型相比，突变型突变体仍输出80％的植物素。因此，我们的结论是一个未知的系统，它是独立的机械敏感性通道，是在依克多因主要出口路线H.泡桐。