Quorum sensing affects biofilm formation through lipopolysaccharide synthesis in Klebsiella pneumoniae
Quorum sensing affects biofilm formation through lipopolysaccharide synthesis in Klebsiella pneumoniae
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DOI：
10.1016/j.resmic.2010.05.014
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发表时间：
2010-09-01
影响因子：
2.6
通讯作者：
Forestier, Christiane
中科院分区：
文献类型：
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作者：
De Araujo, Cecilia;Balestrino, Damien;Forestier, Christiane
肺炎克雷伯氏菌生物膜的形成是由群体感应通过种间自身诱导物的合成来调节的。我们在K. pneumoniae中与大肠杆菌中描述的参与AI-2转运的基因同源的基因，并创建了两个缺失lsrCD和tqsA的同基因突变体。lsrCD和tqsA敲除突变体的细胞外AI-2水平分别显示AI-2浓度升高和降低。负责AI-2合成的基因luxS的转录水平在tqsA突变体的无柄细胞中增加。相反，AI-2输入调节基因lsrR和lsrK的表达降低。此外，两个突变体lsrCD和tqsA形成的生物膜具有更大的生物量，但受损的架构。由于胞外多糖在K. pneumoniae生物膜形成，我们研究了它们与AI-2合成的关系。lucD和AI-2转运系统中的突变均不影响三种胶囊多糖相关基因（wzi、wza和wzx）的表达，但均诱导两种脂多糖（LPS）合成相关基因wbbM和wzm的表达增加。因此，AI-2似乎作为生物膜的形成和LPS合成的调节剂在固着K。肺炎细胞。(C)2010年Elsevier Masson SAS。All rights reserved.
Biofilm formation by Klebsiella pneumoniae is modulated by quorum sensing through the synthesis of interspecies autoinducers. We characterized in K. pneumoniae the genes homologous to those described in Escherichia coli involved in AI-2 transport, and created two isogenic mutants deleted of lsrCD and tqsA. The levels of extracellular AI-2 with lsrCD and tqsA knockout mutants showed increased and lowered concentrations of AI-2, respectively. The level of transcripts of luxS, the gene responsible for AI-2 synthesis, was increased in sessile cells of the tqsA mutant. In contrast, the expression of the AI-2 import regulator genes lsrR and lsrK was decreased. In addition, the two mutants lsrCD and tqsA formed biofilms with greater biomass but impaired architecture. Since exopolysaccharides play a main role in K. pneumoniae biofilm formation, we investigated their relationship with AI-2 synthesis. None of the mutations in lucD and the AI-2 transport systems affected the expression of three capsule polysaccharide-related genes (wzi, wza and wzx), but all induced an increase in the expression of two lipopolysaccharide (LPS)-synthesis-related genes, wbbM and wzm. AI-2 therefore seems to act as a regulator of biofilm formation and LPS synthesis in sessile K. pneumoniae cells. (C) 2010 Elsevier Masson SAS. All rights reserved.