The luxS gene functions in the pathogenesis of avian pathogenic Escherichia coli
The luxS gene functions in the pathogenesis of avian pathogenic Escherichia coli
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luxS基因在禽致病性大肠杆菌发病机制中的作用
DOI：
10.1016/j.micpath.2012.09.008
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发表时间：
2013-02-01
影响因子：
3.8
通讯作者：
Yu, Shengqing
中科院分区：
文献类型：
--
作者：
Han, Xiangan;Bai, Hao;Yu, Shengqing
禽致病性大肠杆菌（AvianpathogenicEscherichiacoli，APEC）是引起禽大肠杆菌病（Aviancolibacillosis）的病原菌，是世界范围内最严重的家禽传染病. LuxS基因的产物LuxS介导群体感应（quorum sensing，QS）机制。这涉及到自诱导物-2（AI-2）的产生，它调节不同细菌的重要生理特性和各种适应过程。在这项研究中，luxS基因缺失的APEC突变株，三角洲DE 17，构建使用菌株DE 17。生物发光分析表明，缺失luxS基因消除了细菌中QS信号AI-2的产生。进一步的研究表明，DE 17中luxS基因的缺失使细菌在雏鸭中的毒力降低了31.5倍，基于50%致死剂量的测量。该突变株的粘附能力和侵袭能力较野生株DE 17分别降低了50.0%和40.7%。突变株在体内的存活率也有所降低：与野生型菌株DE 17相比，突变株在感染的肝脏、脾脏和血液中的细菌载量分别降低了46.4倍、5.2倍和3.7倍。实时荧光定量PCR检测结果进一步表明，突变株Delta DE 17与DE 17相比，其毒力相关基因iucD、fyuA、vat、ompA、iss、fimC和tsh的mRNA水平显著降低（p <0. 05）。此外，luxS基因的缺失降低了细菌的运动性。本研究提示luxS基因在鸡致病性大肠杆菌引起的疾病中起作用。杆菌(C)2012爱思唯尔有限公司保留所有权利。
Avian pathogenic Escherichia coli (APEC) causes avian colibacillosis, the most significant infectious bacterial disease of poultry worldwide. LuxS, the product of the luxS gene, mediates the quorum sensing (QS) mechanism. This involves the production of autoinducer-2 (AI-2), which regulates important physiological traits and a variety of adaptive processes in different bacteria. In this study, a luxS gene deleted APEC mutant strain, Delta DE17, was constructed using strain DE17. Analysis of bioluminescence indicated that deletion of the luxS gene abolished the production of the QS signal AI-2 in the bacteria. Further studies showed that deletion of the luxS gene in DE17 reduced the bacterial virulence by 31.5-fold in ducklings, based on the measurement of the 50% lethal dose. The mutant strain reduced significantly the abilities of adherence and invasion, by 50.0% and 40.7% respectively, compared with the wild strain DE17. The mutant strain also showed reduced survival in vivo: the bacterial loads of the mutant strain in infected liver, spleen and blood were 46.4-fold, 5.2-fold, and 3.7-fold reduced, respectively, compared with the wild-type strain DE17. Real-time polymerase chain reaction (PCR) demonstrated further that the mRNA levels of the virulence-related genes iucD, fyuA, vat, ompA, iss, fimC and tsh were significantly decreased in the mutant strain Delta DE17, when compared with DE17 (p < 0.05). In addition, the deletion of the luxS gene reduced the motility of the bacterium. This study suggests that the luxS gene functions in the pathogenesis of diseases caused by avian pathogenic E. coli. (C) 2012 Elsevier Ltd. All rights reserved.