After the discovery of Corynebacterium glutamicum from avian feces-contaminated soil, its enigmatic L-glutamate secretion by corynebacterial MscCG-type mechanosensitive channels has been utilized for industrial monosodium glutamate production. Bacterial mechanosensitive channels are activated directly by increased membrane tension upon hypoosmotic downshock; thus; the physiological significance of the corynebacterial L-glutamate secretion has been considered as adjusting turgor pressure by releasing cytoplasmic solutes. In this review, we present information that corynebacterial mechanosensitive channels have been evolutionally specialized as carriers to secrete L-glutamate into the surrounding environment in their habitats rather than osmotic safety valves. The lipid modulation activation of MscCG channels in L-glutamate production can be explained by the “Force-From-Lipids” and “Force-From-Tethers” mechanosensing paradigms and differs significantly from mechanical activation upon hypoosmotic shock. The review also provides information on the search for evidence that C. glutamicum was originally a gut bacterium in the avian host with the aim of understanding the physiological roles of corynebacterial mechanosensing. C. glutamicum is able to secrete L-glutamate by mechanosensitive channels in the gut microbiota and help the host brain function via the microbiota–gut–brain axis.

中文翻译：

---

谷氨酸棒杆菌机械传感：从渗透调节到禽类微生物群-肠-脑轴的 L-谷氨酸分泌

在从禽类粪便污染的土壤中发现谷氨酸棒状杆菌后，其通过棒状杆菌MSCCG型机械敏感通道分泌的神秘L-谷氨酸已被用于工业味精生产。低渗下冲击时膜张力增加，直接激活细菌机械敏感通道；因此; 棒状杆菌L-谷氨酸分泌的生理意义被认为是通过释放细胞质溶质来调节膨压。在这篇综述中，我们提出了这样的信息：棒状杆菌机械敏感通道在进化上已被专门化为将 L-谷氨酸分泌到其栖息地周围环境中的载体，而不是渗透安全阀。L-谷氨酸生产中MscCG通道的脂质调节激活可以通过“来自脂质的力”和“来自系绳的力”机械传感范例来解释，并且与低渗休克时的机械激活显着不同。该综述还提供了有关寻找谷氨酸棒状杆菌最初是鸟类宿主肠道细菌的证据的信息，目的是了解棒状杆菌机械传感的生理作用。谷氨酸棒杆菌能够通过肠道微生物群中的机械敏感通道分泌L-谷氨酸，并通过微生物群-肠-脑轴帮助宿主大脑发挥功能。