群感效應(yīng)一詞來源于生物科學(xué)研究中的術(shù)語——Quorum-sensing。Some bacteria use quorum sensing to monitor their local population density. They accomplish this by secreting and monitoring small diffusible signaling molecules. These molecules mediate cell-cell communication for the bacteria with the result that certain traits are only expressed when the bacteria are crowded together. The signal molecules accumulate when cells are crowded together and when the concentration reaches a threshold, receptors signal a change in gene expression. 有些細(xì)菌自身能產(chǎn)生一些可擴散的信號分子,這些信號分子穿出和進入細(xì)胞,并可在環(huán)境中積累。隨著細(xì)菌群體密度的增大,這些信號分子在環(huán)境中積累的濃度也增加。細(xì)菌通過感受環(huán)境中這些信號分子的濃度,能判斷其群體的大小,當(dāng)這些信號分子在環(huán)境中積累到一定濃度,其在細(xì)菌細(xì)胞中的積累也達到臨界濃度(高濃度),這時細(xì)菌的某些特定基因才得以表達。這種現(xiàn)象稱為細(xì)菌的quorum-sensing 。
許多種革蘭氏陰性細(xì)菌利用Quorum-sensing調(diào)節(jié)其特定基因的表達。高絲氨酸內(nèi)酯(AHLs)是這種作用的最普遍的信號分子。