近日，来自耶鲁大学的研究者表示，致病菌拥有一些类似于传感器的结构来激活毒性因子的表达，进而引发诸如食物中毒或者结核病等疾病。这或许为开发抵御疾病感染的新药或者新的疗法提供一些思路。
研究者Groisman表示，永远不会有一个地方没有沙门氏菌，该菌在许多动物宿主中存在，当然你可以尽量避免沙门氏菌或者学会如何抵御沙门氏菌的感染。每年成千上万人死于沙门氏菌引发的食物中毒，好几千万人会遭遇该菌的感染，沙门氏菌是一个公众危害的主要病菌。
研究者揭示了是否外部信号可以引发沙门氏菌自身毒性因子的表达，研究者研究了巨噬细胞吞噬沙门氏菌后所发生分子链反应，巨噬细胞是可以对细菌侵入机体做出有效反应的免疫细胞，当沙门氏菌被吞噬以后，其会快速再生，然后逃过免疫系统监视，进而继续引发感染。
研究者刊登在Nature上的文章发现了环境并不是引发沙门氏菌毒性因子表达的直接威胁，而沙门氏菌周围酸度水平的变化会引发菌体ATP水平的增加，ATP的增加可以激活菌体毒力因子的表达，这样使得沙门氏菌可以在宿主内引发感染并且不断寄生在宿主身上。
在细菌变得非常有毒性之前，内部的传感器协同其它必要的因子都扮演着重要作用，理解这些过程将帮助科学家开发出新的防御沙门氏菌感染的武器。（生物谷Bioon.com）
编译自：Internal cellular sensors make Salmonella dangerous: study
doi:10.1038/nature11090
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Control of a Salmonella virulence locus by an ATP-sensing leader messenger RNA
Eun-Jin Lee & Eduardo A. Groisman
The facultative intracellular pathogen Salmonella enterica resides within a membrane-bound compartment inside macrophages1. This compartment must be acidified for Salmonella to survive within macrophages2, possibly because acidic pH promotes expression of Salmonella virulence proteins3, 4. We reasoned that Salmonella might sense its surroundings have turned acidic not only upon protonation of the extracytoplasmic domain of a protein sensor5 but also by an increase in cytosolic ATP levels, because conditions that enhance the proton gradient across the bacterial inner membrane stimulate ATP synthesis6, 7. Here we report that an increase in cytosolic ATP promotes transcription of the coding region for the virulence gene mgtC, which is the most highly induced horizontally acquired gene when Salmonella is inside macrophages8. This transcript is induced both upon media acidification and by physiological conditions that increase ATP levels independently of acidification. ATP is sensed by the coupling/uncoupling of transcription of the unusually long mgtC leader messenger RNA and translation of a short open reading frame located in this region. A mutation in the mgtC leader messenger RNA that eliminates the response to ATP hinders mgtC expression inside macrophages and attenuates Salmonella virulence in mice. Our results define a singular example of an ATP-sensing leader messenger RNA. Moreover, they indicate that pathogens can interpret extracellular cues by the impact they have on cellular metabolites.
