很多细菌利用群体感应来进行细胞与细胞之间的通信，从而对基因表达实施依赖于种群数量的控制。这个过程中所涉及的信号分子通常为acyl-homoserine lactones (acyl-HSLs)，它们与脂肪酸基团相结合，来通过在不同亚组基因上发挥作用的一系列不同信号受体提供特异性。目前只有少数这种信号已知，但在光合作用细菌Rhodopseudomonas palustris中所发现的HSL主题上的一个新变化表明，也许存在更多这种信号。该细菌用一种与脂肪性acyl-HSL合成酶相似的酶来从环境p-香豆酸生成p-coumaroyl-HSL，而不是利用来自细胞内的脂肪酸。该细菌有一个信号受体，它通过对p-coumaroyl-HSL做出反应来全面调控基因表达。其他种类的细菌也制造p-coumaroyl-HSL，所以可能存在环境条件下的种内通信。（生物谷Bioon.com）
生物谷推荐原始出处：
Nature 454, 595-599 (24 July 2008) | doi:10.1038/nature07088; Received 18 April 2008;
A new class of homoserine lactone quorum-sensing signals
Amy L. Schaefer1, E. P. Greenberg1, Colin M. Oliver2, Yasuhiro Oda1, Jean J. Huang1, Gili Bittan-Banin1, Caroline M. Peres3, Silke Schmidt4, Katarina Juhaszova1, Janice R. Sufrin2 & Caroline S. Harwood1
1 Department of Microbiology, University of Washington, Washington 98195, USA
2 Molecular Pharmacology and Cancer Therapeutics Program, Roswell Park Cancer Institute, State University of New York at Buffalo, Buffalo, New York 14263, USA
3 Danisco Genencor, Palo Alto, California 94304, USA
4 Institute of Molecular Biosciences, University of Frankfurt, Frankfurt 60438, Germany
Correspondence to: Caroline S. Harwood1 Correspondence and requests for materials should be addressed to C.S.H. (Email: csh5@u.washington.edu).
Abstract
Quorum sensing is a term used to describe cell-to-cell communication that allows cell-density-dependent gene expression. Many bacteria use acyl-homoserine lactone (acyl-HSL) synthases to generate fatty acyl-HSL quorum-sensing signals, which function with signal receptors to control expression of specific genes. The fatty acyl group is derived from fatty acid biosynthesis and provides signal specificity, but the variety of signals is limited. Here we show that the photosynthetic bacterium Rhodopseudomonas palustris uses an acyl-HSL synthase to produce p-coumaroyl-HSL by using environmental p-coumaric acid rather than fatty acids from cellular pools. The bacterium has a signal receptor with homology to fatty acyl-HSL receptors that responds to p-coumaroyl-HSL to regulate global gene expression. We also found that p-coumaroyl-HSL is made by other bacteria including Bradyrhizobium sp. and Silicibacter pomeroyi. This discovery extends the range of possibilities for acyl-HSL quorum sensing and raises fundamental questions about quorum sensing within the context of environmental signalling.
