Fig. 6
AI-2-mediated quorum sensing system in YD25T. a Distribution and comparison of gene organization in the complete lsr operon between the Serratia sp. and the S. typhimurium/E. coli. The orientation of the arrows indicates the direction of transcription; b Phylogenetic relationships based on the concatenated amino acid sequences of complete Lsr protein and LuxS. Boxes represent the strains in which the biosynthetic gene cluster of prodigiosin (red) or serrawettin W2 (blue) are observed in the genome. Bootstrap analysis (1000 resamplings) was used to evaluate the topology of the NJ tree. Bar, 0.005 substitutions per nucleotide position. All sequences were retrieved from the NCBI database or in published genome projects. c AI-2 bioassay of YD25T by the Fe (III) ion reduction assay. Representative absorption spectra of 10 mM Fe(III)-1,10-phenanthroline with 60 μg/mL ascorbic acid, a cell-free supernatant sample of YD25T or KB medium; d Cell growth of YD25T cultures in KB and the production of extracellular AI-2 levels in the culture media. Numbers show an average of three replications and are derived from one independent sample