Production of acylated homoserine lactone by Gram-positive bacteria isolated from marine water
Production of acylated homoserine lactone by Gram-positive bacteria isolated from marine water
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DOI：
10.1111/1574-6968.12123
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发表时间：
2013-06-01
影响因子：
2.1
通讯作者：
Doble, Mukesh
中科院分区：
文献类型：
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作者：
Biswa, Pramal;Doble, Mukesh
基于酰化高丝氨酸内酯（阿勒）的群体感应（QS）仅存在于革兰氏阴性微生物中。本文报道了从海水中分离到的一种新的革兰氏阳性微生物，它能产生阿勒。分离物（GenBank：JF 915892，命名为MPO）能够诱导阿勒生物报告基因，即紫色色杆菌CV 026、根癌土壤杆菌A136和大肠杆菌JM 109（psb 1075）。该诱导剂的特征在于C3-氧代-辛酰基高丝氨酸内酯（OOHL），其产量在生物体的稳定生长期达到最大值15.6gL-1。MPO提取物在外源性添加时抑制相同生物体的生物膜形成并降低细胞外聚合物，表明AHL相关的表型性状。来自MPO的可能的LuxR同源物（指定为ExgR）的分离序列显示类似的功能结构域，并且包含来自其他已知细菌QS LuxR调节剂的LuxR中的保守残基。还发现ExgR下游紧邻的序列与恶臭假单胞菌的已知LuxI合酶显示同源性。qPCR分析表明添加阿勒后exgR mRNA增加，进一步证明ExgR作为QS调节剂的作用。
Acylated homoserine lactone (AHL)-based quorum sensing (QS) has been reported to be present only in Gram-negative microorganisms. Isolation of a novel Gram-positive microorganism from sea water, capable of producing AHL, is reported here. The isolate (GenBank: JF915892, designated as MPO) belonging to the Exiguobacterium genera is capable of inducing the AHL bioreporters, namely Chromobacterium violaceum CV026, Agrobacterium tumefaceins A136, and E.coli JM 109(psb1075). This inducer is characterized as C3-oxo-octanoyl homoserine lactone (OOHL), and its production reaches a maximum of 15.6gL1, during the stationary growth phase of the organism. MPO extract when exogenously added inhibits the formation of biofilm for the same organism and lowers the extracellular polymeric substances, indicating an AHL-associated phenotypic trait. The isolated sequence of a probable LuxR homolog from MPO (designated as ExgR) shows similar functional domains and contains conserved residues in LuxR from other known bacterial QS LuxR regulators. Also present immediately downstream to ExgR was found a sequence showing homology to known LuxI synthase of Pseudomonas putida. qPCR analysis suggests an increment in exgR mRNA on addition of AHL, further proving the role of ExgR as a QS regulator.