Systematically integrated metabonomic-proteomic studies of Escherichia coli under ciprofloxacin stress.

Many antibiotics are used to kill pathogenic Escherichia coli each year, resulting in an increase in the number of antibiotic-resistant strains. In this study, an integrated metabonomic-proteomic method was performed to systematically compare the profiles of metabolites and proteins with or without ciprofloxacin (CFLX) treatment. Proteomics identified 290 altered proteins including 143 with decreased and 147 increased expression, respectively. Metabonomics identified 65 altered metabolites including 58 and 7 with decreased and increased expression, respectively. The integrated analysis showed that the CFLX inhibited the DNA replication and increased the expression of DNA gyrase and DNA topoisomerase 1, while causing a sharp decrease in metabolic activity such as the alanine, aspartate and glutamate metabolism. Moreover, CFLX affected the biosynthesis of aminoacyl- transfer RNAs (tRNAs), leading to an increase in aminoacyl-tRNAs ligases, but limited the aminoacyl-tRNAs-mediated-biosynthesis of related amino acids. In this study, we identified the metabolite and protein profiles under CFLX stress, indicating the mode of action of antibiotics in E. coli. Furthermore, the decreasing metabolic activity in E. coli may be an effective strategy to escape killing by antimicrobials or toxic compounds. The results of this study will advance our understanding of the mechanisms underlying the resistance of bacteria to antibiotics. BIOLOGICAL SIGNIFICANCE: To investigate the biological impact of antibiotics stress on Escherichia coli, we applied an integrated metabonomic-proteomic method to systematically compare the profiles of metabolites and proteins between with and without antibiotics ciprofloxacin (CFLX) treatment. Following bioinformatics analysis showed that CFLX inhibited the DNA replication and increased the expression of DNA gyrase and DNA topoisomerase, while causing a sharp increase in the alanine, aspartate and glutamate metabolism. Moreover, CFLX affected the biosynthesis of tRNAs and limited the generation of related amino acids metabolites. In a summary, our results will provide the metabolite and protein profiles under CFLX stress, indicating the mode of action of antibiotics in E. coli. The results of this study will advance our understanding of the mechanisms underlying the resistance of bacteria to antibiotics.