Analysis Of Microbial Metabolites Network Based On Chromatography-mass Spectrometry

Metabolomics, as a new set of research techniques, has been widely used in micro-organism, and its related applications of technology to expand the development of the instrument has a close relationship. The present analytical techniques used in metabolomics reserch include capillary electrophoresis-mass spectrometry (CE-MS), nuclear magnetic resonance (NMR), gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS) techniques. Gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry has been applied more generally.Thus it is most effective that using metabolomics and analysis method to folly understand the physiological functions of micro-organisms. As a new omics technique, metabolomics has greatly enriched systems biology research and become one of the most promising methods to the research of life sciences.In this paper, Escherichia coli 1.1566 (E.colil.1566) and its gene knockout strains were investigated by GC-MS and LC-MS.The analysis platform of microbial metabolomics was established.Then,aiming at small molecular metabolites, metabolic fingerprint and metabolic network analysis were investigated. Firstly, GC-MS method was employed to profile intercellular metabolites fingerprint of E.colil.1566 and △sdhAB in glycine nitrogen source. Multivariate data analysis revealed that it was 8 different metabolites between E.coli1566 and △sdhAB. Correlation analysis of the detected amino acids indicated that relationship among pro line, isoleucine and glutamine was changed greatly.Secondly, we evaluated a new metabolic quenching method by GC-MS analysis, and it was called physiological saline (N.S.) quenching method. This method showed more effectively improvement on metabolites extraction then cold methanol quenching method. Subsequently, this method integrated with LC-MS for metabolic fingerprint analysis.Than, it was found there were 10 different metabolites between the E.colil.1566 and BC101.Thirdly, combinating metabolic analysis and gene chip analysis to study metabolic network of Escherichia coli and its gene knockout strains under the fructose as carbon source.Finally, a glucose pulse was exerted on the continuous culture of Saccharomyces cerevisiae. The major intercellular metabolites were determined from cultures sampled in different time points. Parameter estimation was conducted by utilizing the quantitation data and a glycolysis model.Metabolic control analysis showed that hexose transport system, hexose kinase and phosphofructokinase were of high flux control coefficients. Simulation performed by randomly changing the inter- and intra-cellular concentrations of the metabolites indicated that cells could restore its energy charge states with in one minute.