Figure 5.
P cycle and energy metabolism in VA-RCAZ.
Notes: (A) Abundance of five metabolites in the P cycle. (B) Flux of the P cycle and biosynthesis of fatty acids in VA-RCAZ compared with VA-S. (C) Activity of enzymes (PDH, CS, IDH, OGDH, SDH, MDH, and ICL) in the P cycle. Overnight VA-S and VA-RCAZ were diluted to 1:100 using fresh 3% NaCl LB medium and grown at 30°C for 3 hours. (D) Interactive Pathways Explorer (iPath) analysis. Metabolic network pathways in VA-RCAZ were analyzed with iPath 2.0 (http://pathways2.embl.de/iPath2.cgi#). Analyses of the 42 differential metabolites (the other metabolites are not recognized in the metabolic network pathways). Red: increase; blue: decrease. (E) Percent survival of VA-S in the presence or absence of inhibitors (furfural and malonate). Overnight VA-S were incubated with CAZ (5 μg/mL) plus furfural (5, 20, and 80 μM) or malonate (5, 10, and 20 mM) in M9 minimal medium plus NaAc (10 mM) at 30°C for 6 hours. (F) Enzyme activity of PDH and SDH in the presence or absence of inhibitors (furfural and malonate). Overnight VA-S were incubated with furfural (80 μM) or malonate (20 mM) in M9 minimal medium plus NaAc (10 mM) at 30°C for 6 hours. Results (A, C, E, and F) are displayed as mean ± SEM, and significant differences are identified as determined by Student’s t-test. *P<0.05, **P<0.01. At least three biologic repeats were carried out.
Abbreviations: CAZ, ceftazidime; ICL, isocitrate lyase; IDH, isocitrate dehydrogenase; MDH, malate dehydrogenase; P cycle, pyruvate cycle; PDH, pyruvate dehydrogenase; SDH, succinate dehydrogenase; TCA, tricarboxylic acid; VA-RCAZ, ceftazidime-resistant Vibrio alginolyticus; VA-S, ceftazidime-sensitive Vibrio alginolyticus.