title: Quantitative determination of AI-2 quorum-sensing signal of bacteria using high performance liquid chromatography-tandem mass spectrometry.
abstract: Autoinducer 2 (AI-2), an important bioactive by-product of the LuxS-catalyzed S-ribosylhomocysteine cleavage reaction in the activated-methyl-cycle, has been suggested to serve as a universal intra- and inter-species signaling molecule. The development of reliable and sensitive methods for quantitative determination of AI-2 is highly desired. However, the chemical properties of AI-2 cause difficulty in its quantitative analysis. Herein, we report a high performance liquid chromatography-tandem mass spectrometric method that enables reproducible and sensitive measurement of AI-2 concentrations in complex matrixes. 4,5-Dimethylbenzene-1,2-diamine (DMBDM), an easy-to-obtain commercial reagent, was used for the derivatization treatment. The assay was linear in the concentration range of 1.0-1000ng/mL (R2=0.999) and had a lower limit of quantification of 0.58ng/mL. The method exhibited several advantages, e.g., high selectivity, wide linear response range, and good sensitivity. Furthermore, the effectiveness of the method was further validated through measuring AI-2 concentrations in the cell-free culture supernatant from Escherichia coli wild type.
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, China; School of Medical Engineering, Hefei University of Technology, Hefei 230009, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Xu
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, China.
authors.forename: Xiangning
authors.initials: X
authors.lastname: Song
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, China.
authors.forename: Peijie
authors.initials: P
authors.lastname: Cai
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, China.
authors.forename: Guoping
authors.initials: G
authors.lastname: Sheng
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, China. Electronic address: hqyu@ustc.edu.cn.
authors.forename: Hanqing
authors.initials: H
authors.lastname: Yu
mesh_terms: D002853:Chromatography, Liquid; D004926:Escherichia coli; D006714:Homoserine / Q000031:analogs & derivatives* / Q000032:analysis; D007783:Lactones / Q000032:analysis*; D053038:Quorum Sensing; D053719:Tandem Mass Spectrometry
chemical_list: D007783:Lactones; C091088:N-octanoylhomoserine lactone; D006714:Homoserine
keywords: Autoinducer-2; Escherichia coli wild type; HPLC–MS/MS; Quantitative analysis; Quorum sensing; Signal transduction