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Attenuation of Edwardsiella tarda virulence by small peptides that interfere with LuxS/autoinducer type 2 quorum sensing.

Authors :
Zhang M
Jiao XD
Hu YH
Sun L
Source :
Applied and environmental microbiology [Appl Environ Microbiol] 2009 Jun; Vol. 75 (12), pp. 3882-90. Date of Electronic Publication: 2009 May 01.
Publication Year :
2009

Abstract

Edwardsiella tarda is a gram-negative pathogen with a broad host range that includes humans, animals, and fish. Recent studies have shown that the LuxS/autoinducer type 2 (AI-2) quorum sensing system is involved in the virulence of E. tarda. In the present study, it was found that the E. tarda LuxS mutants bearing deletions of the catalytic site (C site) and the tyrosine kinase phosphorylation site, respectively, are functionally inactive and that these dysfunctional mutants can interfere with the activity of the wild-type LuxS. Two small peptides, 5411 and 5906, which share sequence identities with the C site of LuxS, were identified. 5411 and 5906 proved to be inhibitors of AI-2 activity and could vitiate the infectivity of the pathogenic E. tarda strain TX1. The inhibitory effect of 5411 and 5906 on AI-2 activity is exerted on LuxS, with which these peptides specifically interact. The expression of 5411 and 5906 in TX1 has multiple effects (altering biofilm production and the expression of certain virulence-associated genes), which are similar to those caused by interruption of luxS expression. Further study found that it is very likely that 5411 and 5906 can be released from the strains expressing them and, should TX1 be in the vicinity, captured by TX1. Based on this observation, a constitutive 5411 producer (Pseudomonas sp. strain FP3/pT5411) was constructed in the form of a fish commensal isolate that expresses 5411 from a plasmid source. The presence of FP3/pT5411 in fish attenuates the virulence of TX1. Finally, it was demonstrated that fish expressing 5411 directly from tissues exhibit enhanced resistance against TX1 infection.

Details

Language :
English
ISSN :
1098-5336
Volume :
75
Issue :
12
Database :
MEDLINE
Journal :
Applied and environmental microbiology
Publication Type :
Academic Journal
Accession number :
19411415
Full Text :
https://doi.org/10.1128/AEM.02690-08