An N-Acyl Homoserine Lactone Synthase in the Ammonia-Oxidizing Bacterium Nitrosospira multiformis
An N-Acyl Homoserine Lactone Synthase in the Ammonia-Oxidizing Bacterium Nitrosospira multiformis
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氨氧化细菌多形亚硝螺菌中的 N-酰基高丝氨酸内酯合酶
DOI：
10.1128/aem.03361-13
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发表时间：
2014-02-01
影响因子：
4.4
通讯作者：
Zhuang, Guoqiang
中科院分区：
文献类型：
--
作者：
Gao, Jie;Ma, Anzhou;Zhuang, Guoqiang
多形亚硝化螺旋菌参与了氮循环过程的影响。在这里，我们报道了多形虫中一个功能性群体感应信号合成酶的存在和特征。一个基因（nmuI）在产生与n -酰基高丝氨酸内酯（AHL）合成酶蛋白家族高度相似的蛋白质中起作用。将产生LuxI同源物的nmuI引入大肠杆菌，采用AHL生物传感器和液相色谱-质谱（LC-MS）检测两种AHL （C14-AHL和3-oxo-C14-AHL）。然而，用酸化的乙酸乙酯提取多形假丝酵母培养上清液，没有得到能够激活生物传感器或LC-MS检测的AHL产物。通过反转录- pcr分析，发现nmuI基因在多形N.霉属中有转录，且该氨氧化菌株的LuxR同源物（NmuR）对长链AHL信号具有较高的敏感性。降解实验表明，AHL信号的缺失可能归因于该菌株可能具有AHL灭活活性。总之，一个AHL合成酶基因（nmuI）作为长链AHL的生产者已经在一种趋化营养氨氧化微生物中被发现，这一结果为完善多形奈米菌的调控网络提供了机会。
ABSTRACT The chemolithoautotrophic bacterium Nitrosospira multiformis is involved in affecting the process of nitrogen cycling. Here we report the existence and characterization of a functional quorum sensing signal synthase in N. multiformis. One gene (nmuI) playing a role in generating a protein with high levels of similarity to N-acyl homoserine lactone (AHL) synthase protein families was identified. Two AHLs (C14-AHL and 3-oxo-C14-AHL) were detected using an AHL biosensor and liquid chromatography-mass spectrometry (LC-MS) when nmuI, producing a LuxI homologue, was introduced into Escherichia coli. However, by extracting N. multiformis culture supernatants with acidified ethyl acetate, no AHL product was obtained that was capable of activating the biosensor or being detected by LC-MS. According to reverse transcription-PCR, the nmuI gene is transcribed in N. multiformis, and a LuxR homolog (NmuR) in this ammonia-oxidizing strain showed great sensitivity to long-chain AHL signals by solubility assay. A degradation experiment demonstrated that the absence of AHL signals might be attributed to the possible AHL-inactivating activities of this strain. To summarize, an AHL synthase gene (nmuI) acting as a long-chain AHL producer has been found in a chemolithotrophic ammonia-oxidizing microorganism, and the results provide an opportunity to complete the knowledge of the regulatory networks in N. multiformis.