Quorum sensing and c-di-GMP-dependent alterations in gene transcripts and virulence-associated phenotypes in a clinical isolate of Aeromonas hydrophila

Elena V. Kozlova, Bijay K. Khajanchi, Jian Sha, Ashok K. Chopra

Research output: Contribution to journalArticle

23 Scopus citations

Abstract

Recently, we demonstrated that the LuxS-based quorum sensing (QS) system (AI-2) negatively regulated the virulence of a diarrheal isolate SSU of Aeromonas hydrophila, while the ahyRI-based (AI-1) N- acyl-homoserine lactone system was a positive regulator of bacterial virulence. Thus, these QS systems had opposing effects on modulating biofilm formation and bacterial motility in vitro models and in vivo virulence in a speticemic mouse model of infection. In this study, we linked these two QS systems with the bacterial second messenger cyclic diguanosine monophosphate (c-di-GMP) in the regulation of virulence in A. hydrophila SSU. To accomplish this, we examined the effect of overproducing a protein with GGDEF domain, which increases c-di-GMP levels in bacteria, on the phenotype and transcriptional profiling of genes involved in biofilm formation and bacterial motility in wild-type (WT) versus its QS null mutants. We provided evidence that c-di-GMP overproduction dramatically enhanced biofilm formation and reduced motility of the WT A. hydrophila SSU, which was equitable with that of the Δ luxS mutant. On the contrary, the ahyRI mutant exhibited only a marginal increase in the biofilm formation with no effect on motility when c-di-GMP was overproduced. Overall, our data indicated that c-di-GMP overproduction modulated transcriptional levels of genes involved in biofilm formation and motility phenotype in A. hydrophila SSU in a QS-dependent manner, involving both AI-1 and AI-2 systems.

Original languageEnglish (US)
Pages (from-to)213-223
Number of pages11
JournalMicrobial Pathogenesis
Volume50
Issue number5
DOIs
StatePublished - May 1 2011

Keywords

  • AI-1 (ahyRI-based) QS
  • AI-2 (luxS-based) QS
  • Aeromonas hydrophila
  • Biofilm
  • C-di-GMP
  • Motility
  • QS

ASJC Scopus subject areas

  • Microbiology
  • Infectious Diseases

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