title: A luxS-dependent transcript profile of cell-to-cell communication in Klebsiella pneumoniae.
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 operon luxCDABE 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 luxS transcription 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.
authors.affiliation: Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266555, People's Republic of China. hzhu@live.cn
authors.forename: Hu
authors.initials: H
authors.lastname: Zhu
authors.forename: Hui-Jun
authors.initials: HJ
authors.lastname: Liu
authors.forename: Shou-Jiao
authors.initials: SJ
authors.lastname: Ning
authors.forename: Yu-Li
authors.initials: YL
authors.lastname: Gao
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D013437:Carbon-Sulfur Lyases / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D007711:Klebsiella pneumoniae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D053038:Quorum Sensing; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria