The metabolic diversity of Escherichia coli strains (non-pathogenic E. coli ATCC 25922, and pathogenic E. coli O157:H7, O26:H11, O45:H2, O103:H11, O111, O121:H19, and O145) was tested using nuclear magnetic resonance. Based on two representative two-dimensional 1H-13C spectra, 38 metabolites were identified in E. coli intracellular samples. Principal component analysis indicated that metabolites including lysine, arginine, α-ketoglutaric acid, adenosine, and fumaric acid were responsible for the separation of E. coli ATCC 25922. Relatively large metabolic differences between ATCC 25922 and the pathogenic strains were recoded. The most varied pairwise group (ATCC 25922 vs. O26:H11) was further analysed. The screened metabolites and enrichment pathway tests revealed different amino acid metabolism and higher requirement for energy production in the pathogenic strains. The acidic responses of the selected strains were further tested. The in vitro and in vivo inactivation kinetics, morphological changes, and protein leakage showed higher acid tolerance of E. coli O26:H11. Metabolic analysis of the two strains under acidic stress revealed alternative metabolites and pathways in the two groups. Pathogenic O26:H11 was characterised by higher energy production and amino acid metabolism (lysine and glutamic acid). Real-time PCR tests confirmed that glutamic acid dependent decarboxylase/antiporter system was the major acid resistance mechanism.

中文翻译：

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包括“六大”在内的八种大肠埃希氏菌的代谢特征以及通过NMR光谱揭示的选定菌株的酸性反应。

使用以下方法测试了大肠杆菌菌株（非致病性大肠杆菌ATCC 25922和致病性大肠杆菌O157：H7，O26：H11，O45：H2，O103：H11，O111，O121：H19和O145）的代谢多样性核磁共振。基于两个代表性的二维1H-13C光谱，在大肠杆菌细胞内样品中鉴定出38种代谢物。主成分分析表明，赖氨酸，精氨酸，α-酮戊二酸，腺苷和富马酸等代谢产物是大肠杆菌ATCC 25922分离的原因。ATCC25922与致病菌株之间的相对较大的代谢差异被重新编码。进一步分析了变化最大的成对组（ATCC 25922对O26：H11）。筛选的代谢物和富集途径测试表明，病原菌株的氨基酸代谢不同，对能量产生的要求更高。进一步测试了所选菌株的酸性反应。体外和体内失活动力学，形态变化和蛋白质泄漏显示大肠杆菌O26：H11具有更高的耐酸性。两种菌株在酸性胁迫下的代谢分析显示了两组中的替代代谢物和途径。致病性O26：H11的特征是更高的能量产生和氨基酸代谢（赖氨酸和谷氨酸）。实时PCR测试证实，谷氨酸依赖性脱羧酶/反转运蛋白系统是主要的耐酸机理。体外和体内失活动力学，形态变化和蛋白质泄漏显示大肠杆菌O26：H11具有更高的耐酸性。两种菌株在酸性胁迫下的代谢分析显示了两组中的替代代谢物和途径。致病性O26：H11的特征在于更高的能量产生和氨基酸代谢（赖氨酸和谷氨酸）。实时PCR测试证实，谷氨酸依赖性脱羧酶/反转运蛋白系统是主要的耐酸机理。体外和体内失活动力学，形态变化和蛋白质泄漏显示大肠杆菌O26：H11具有更高的耐酸性。两种菌株在酸性胁迫下的代谢分析显示了两组中的替代代谢物和途径。致病性O26：H11的特征在于更高的能量产生和氨基酸代谢（赖氨酸和谷氨酸）。实时PCR测试证实，谷氨酸依赖性脱羧酶/反转运蛋白系统是主要的耐酸机理。H11的特征在于更高的能量产生和氨基酸代谢（赖氨酸和谷氨酸）。实时PCR测试证实，谷氨酸依赖性脱羧酶/反转运蛋白系统是主要的耐酸机理。H11的特征在于更高的能量产生和氨基酸代谢（赖氨酸和谷氨酸）。实时PCR测试证实，谷氨酸依赖性脱羧酶/反转运蛋白系统是主要的耐酸机理。