A luxS-dependent transcript profile of cell-to-cell communication in Klebsiella pneumoniae

Molecular BioSystems Pub Date: 2011-09-21 DOI: 10.1039/C1MB05314K

Abstract

Bacterial cells communicate with one another using chemical signaling molecules. The phenomenon is termed quorum sensing. The quorum sensing bacterium Klebsiella pneumoniae secretes a non-homoserine lactone autoinducer in the exponential phase of growth as detected by a Vibrio harveyi reporter assay for autoinducer 2 (AI-2). To further investigate regulation of AI-2 production in K. pneumoniae, the pfs and luxS promoter fusions to an operonluxCDABE reporter were constructed in a low copy number vector, which is derived from pBR322 and pET28a(+) and allows an examination of transcription of the genes in the pathway for signal synthesis. In this study, comparisons were performed on the cell densities of wild-type and recombinant K. pneumoniae, on the transcription activity of pfs and luxS promoters, and on the synthesis of AI-2 as a function of culture time. The results show that luxS expression is constitutive and the transcription of luxS is tightly correlated to AI-2 production in K. pneumoniae because the peaks of AI-2 production and transcriptional level of luxS appear at the same time point. The close relation of the profiles of luxStranscription and AI-2 production was also confirmed with quantitative reverse transcription-PCR technology. These facts support the idea that the quorum sensing in K. pneumoniae is luxS dependent.

Graphical abstract: A luxS-dependent transcript profile of cell-to-cell communication in Klebsiella pneumoniae
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