Agilent chrom station software

Both the sample bacterial preparation and GC-MS analysis were performed as described previously (23 (link)). Briefly, 10 high- and 10 low-virulent strains were cultured in the LB medium with 200 rpm at 37℃ until reaching an optical density at 600 nm (OD600) of 1.0. The aliquot of 10-mL cells was quenched with precooled methanol (Sigma Aldrich) and by ultrasonication. Ribitol (0.1 mg/mL, Sigma Aldrich) was added as an internal standard. The aliquot of the 500-µL supernatant was separated with 12,000 g at 4°C for 10 min and dried by a vacuum centrifugation dryer (Labconco). Methoximation–pyridine hydrochloride (Sigma Aldrich) was added to the dried fraction above and continuously shaken with 200 rpm at 30°C for 90 min. Eighty microliters of N-methyl-N-trimethylsilyltrifluoroacetamide (Sigma Aldrich) was added and incubated at 37°C for 30 min. The data were analyzed using an Agilent 7890A GC and an Agilent 5975C VL MSD detector (Agilent Technologies). The compounds were identified by Agilent Chrom Station software (Agilent Technologies) and the National Institute of Standards and Technology (NIST) library. Every sample was analyzed in duplicate.

Statistical analysis was performed as previously described (38 (link)). Briefly, Agilent Chrom Station software (Agilent Technologies, USA) was used to analyze mass fragmentation spectrum and identify compounds thorough matching data with the National Institute of Standards and Technology (NIST) library and NIST MS search 2.0 program. The data were normalized based on total amount of correction and standardized data containing metabolites, retention times, and peak areas, and prepared for further metabolomics analysis. Significant difference of the standardized data was calculated and selected (P value <0.05) by software IBM SPSS Statistics 19. Cluster analysis was carried out by R software (R × 64 3.6.1). Normalized area of differential metabolites was analyzed with Z-score. Principal-component analysis and S-plot analysis were performed by SIMCA-P + 12.0 software (version 12; Umetrics, Umea, Sweden), and the metabolic pathway was done with MetaboAnalyst 4.0 enrichment. Interactive Pathways (iPath) analysis was conducted with iPath 3.0 (https://pathways.embl.de/). Figures were draw by GraphPad Prism 7.0 and Adobe Illustrator CS6.

Statistical analysis was performed as previously described (38 (link)). Briefly, Agilent Chrom Station software (Agilent Technologies, USA) was used to analyze mass fragmentation spectrum and identify compounds thorough matching data with the National Institute of Standards and Technology (NIST) library and NIST MS search 2.0 program. The data were normalized based on total amount of correction and standardized data containing metabolites, retention times, and peak areas, and prepared for further metabolomics analysis. Significant difference of the standardized data was calculated and selected (P value <0.05) by software IBM SPSS Statistics 19. Cluster analysis was carried out by R software (R × 64 3.6.1). Normalized area of differential metabolites was analyzed with Z-score. Principal-component analysis and S-plot analysis were performed by SIMCA-P + 12.0 software (version 12; Umetrics, Umea, Sweden), and the metabolic pathway was done with MetaboAnalyst 4.0 enrichment. Interactive Pathways (iPath) analysis was conducted with iPath 3.0 (https://pathways.embl.de/). Figures were draw by GraphPad Prism 7.0 and Adobe Illustrator CS6.