Enterohemorrhagic Escherichia coli biofilms are inhibited by 7-hydroxyindole and stimulated by isatin
Enterohemorrhagic Escherichia coli biofilms are inhibited by 7-hydroxyindole and stimulated by isatin
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DOI：
10.1128/aem.00360-07
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发表时间：
2007-07-01
影响因子：
4.4
通讯作者：
Wood, Thomas K.
中科院分区：
文献类型：
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作者：
Lee, Jintae;Bansal, Tarun;Wood, Thomas K.
由于吲哚在固定相中存在于500亩M处，是种间生物膜信号(J.Lee，A.Jayaraman和T.K.Wood，BMC Microbiol.7：42,2007)，我们研究了羟基吲哚作为生物膜信号，发现它们也是肠出血性大肠杆菌O157：117(EHEC)、E.coliK-12和铜绿假单胞菌的无毒跨种生物膜信号。此外，还探讨了EHEC生物膜形成的遗传基础，值得注意的是，与浮游细胞相比，生物膜细胞中的毒力基因受到抑制。在静止条件下的Luria-Bertani(Luria-Bertani)培养基中，7-羟基吲哚使EHEC生物膜形成减少27倍，K-12生物膜形成减少8倍，而不影响浮游细胞的生长。5-羟基吲哚还使EHEC和K-12的生物膜形成分别减少了11倍和6倍。相反，吲哚-2，3-二酮使EHEC的生物膜形成增加了四倍，而对K-12则没有影响。当使用连续流动小室时，共聚焦显微镜显示，在LB中，吲哚使EHEC生物膜的形成减少了6倍，7-羟基吲哚减少了10倍。全转录组分析显示，Isatin通过抑制EHEC中tna ABC的7-37倍抑制吲哚合成，细胞外吲哚水平被发现降低了20倍。此外，Iisatin抑制AI-2转运蛋白lsrABCDFGKR，而显著诱导鞭毛基因flgABCDEFGHIJK和fliAEFGILMNOPQ(导致运动性增加50%)。7-羟基吲哚诱导生物膜抑制/应激调节因子ycfR，抑制cysADIJPU/FLIC(导致细胞活力下降50%)和PurBCDEFHKLMNRT。同基因突变表明，7-羟基吲哚通过半胱氨酸代谢抑制大肠杆菌生物膜。7-羟基吲哚(500亩M)对铜绿假单胞菌PAO1生物被膜的形成也有双重刺激作用，因此，7-羟基吲哚是种间细菌信号，7-羟基吲哚是一种有效的EHEC生物被膜抑制物。
Since indole is present at up to 500 mu M in the stationary phase and is an interspecies biofilm signal (J. Lee, A. Jayaraman, and T. K. Wood, BMC Microbiol. 7:42,2007), we investigated hydroxyindoles as biofilm signals and found them also to be nontoxic interspecies biofilm signals for enterohemorrhagic Escherichia coli O157:117 (EHEC), E. coli K-12, and Pseudomonas aeruginosa. The genetic basis of EHEC biofilm formation was also explored, and notably, virulence genes in biofilm cells were repressed compared to those in planktonic cells. In Luria-Bertani medium (LB) on polystyrene with quiescent conditions, 7-hydroxyindole decreased EHEC biofilm formation 27-fold and decreased K-12 biofilm formation 8-fold without affecting the growth of planktonic cells. 5-Hydroxyindole also decreased biofilm formation 11-fold for EHEC and 6-fold for K-12. In contrast, isatin (indole-2,3-dione) increased biofilm formation fourfold for EHEC, while it had no effect for K-12. When continuous-flow chambers were used, confocal microscopy revealed that EHEC biofilm formation was reduced 6-fold by indole and 10-fold by 7-hydroxyindole in LB. Whole-transcriptome analysis revealed that isatin represses indole synthesis by repressing tnaABC 7- to 37-fold in EHEC, and extracellular indole levels were found to be 20-fold lower. Furthermore, isatin repressed the AI-2 transporters lsrABCDFGKR, while significantly inducing the flagellar genes flgABCDEFGHIJK and fliAEFGILMNOPQ (which led to a 50% increase in motility). 7-Hydroxyindole induces the biofilm inhibitor/stress regulator ycfR and represses cysADIJPU/fliC (which led to a 50% reduction in motility) and purBCDEFHKLMNRT. Isogenic mutants showed that 7-hydroxyindole inhibits E. coli biofilm through cysteine metabolism. 7-Hydroxyindole (500 mu M) also stimulates P. aeruginosa PAO1 biofilm formation twofold; therefore, hydroxyindoles are interspecies bacterial signals, and 7-hydroxyindole is a potent EHEC biofilm inhibitor.