Quorum Sensing inYersinia enterocoliticaControls Swimming and Swarming Motility

Abstract

The Yersinia enterocolitica LuxI homologue YenI directs the synthesis of N-3-(oxohexanoyl)homoserine lactone (3-oxo-C6-HSL) and N-hexanoylhomoserine lactone (C6-HSL). In a Y. enterocolitica yenI mutant, swimming motility is temporally delayed while swarming motility is abolished. Since both swimming and swarming are flagellum dependent, we purified the flagellin protein from the parent and yenI mutant. Electrophoresis revealed that in contrast to the parent strain, the yenI mutant grown for 17 h at 26°C lacked the 45-kDa flagellin protein FleB. Reverse transcription-PCR indicated that while mutation of yenI had no effect on yenR, flhDC (the motility master regulator) or fliA (the flagellar sigma factor) expression, fleB (the flagellin structural gene) was down-regulated. Since 3-oxo-C6-HSL and C6-HSL did not restore swimming or swarming in the yenI mutant, we reexamined the N-acylhomoserine lactone (AHL) profile of Y. enterocolitica. Using AHL biosensors and mass spectrometry, we identified three additional AHLs synthesized via YenI: N-(3-oxodecanoyl)homoserine lactone, N-(3-oxododecanoyl)homoserine lactone (3-oxo-C12-HSL), and N-(3-oxotetradecanoyl)homoserine lactone. However, none of the long-chain AHLs either alone or in combination with the short-chain AHLs restored swarming or swimming in the yenI mutant. By investigating the transport of radiolabeled 3-oxo-C12-HSL and by introducing an AHL biosensor into the yenI mutant we demonstrate that the inability of exogenous AHLs to restore motility to the yenI mutant is not related to a lack of AHL uptake. However, both AHL synthesis and motility were restored by complementation of the yenI mutant with a plasmid-borne copy of yenI.

The Acyl-Homoserine Lactone-Type Quorum-Sensing System Modulates Cell Motility and Virulence of Erwinia chrysanthemi pv. zeae

“…zeae appears to be different from other gram-negative bacterial strains in the mode of QS regulation of bacterial motility. In other bacterial organisms, null mutation of AHL biosynthesis or enzymatic degradation of AHL signal in bacteria either has no effect on swimming motility, as in the case of Pseudomonas aeruginosa (25), or results in decreased swimming and swarming motility, such as in Yersinia enterocolitica (1). In contrast, inactivation of AHL-synthase gene expI Ecz in the bacterial pathogen E. chrysanthemi pv.…”

Salmonella enterica Serovar Typhimurium Can Detect Acyl Homoserine Lactone Production by Yersinia enterocolitica in Mice

“…Like Salmonella, this organism preferentially invades the lymphatic tissues of Peyer's patches (8,9,37). Y. enterocolitica has a quorum sensing system composed of yenI, which encodes an AHL synthase, and yenR, which encodes a LuxR-type AHL receptor (4,5,39). AHL produced by yenI has been detected in mouse tissues following infection with Y. enterocolitica (21).…”

“…The genes regulated by this quorum sensing system have not been identified systematically, but it is known to regulate fleB, which encodes the flagellin subunit (4,5). Swimming motility is temporally delayed and swarming motility is eliminated in a yenI mutant (4,5).…”

Probing the Impact of Ligand Binding on the Acyl-Homoserine Lactone-Hindered Transcription Factor EsaR of Pantoea stewartii subsp. stewartii

“…The class IV proteins maintain a functional conformation and bind DNA in the absence of their cognate AHL; biological activity is actually hindered by the presence of the AHL N-3-oxo-hexanoyl-L-homoserine lactone, in the majority of cases (reviewed in reference 24). Examples of these homologues, besides EsaR from P. stewartii, include ExpR from Erwinia chrysanthemi and Pectobacterium carotovorum (7,21), YenR from Yersinia enterocolitica (1,25), and EanR from Pantoea ananatis (16). Structurally, the members of the EsaR subfamily also share the characteristics of having an extended linker region between the AHL-binding N-terminal domain (NTD) and an extended DNA-binding C-terminal domain (CTD) (23).…”