Effects of pH on Infection Phenotypes and Extracellular Products Properties of Vibrio mimicus

PurposeTo study the effect of pH on the phenotypes and extracellular products properties of Vibrio mimicus infection.

MethodsThe proliferation, swimming motility, self-aggregation, biofilm formation, and the protein mass concentration, enzyme activity, hemolytic, cytotoxicity and virulence of extracellular products (ECPs) of V. mimicus were determined under different pH (6.0, 7.0, 8.0, 8.5, 9.0) conditions.

ResultsAt pH 6.0-9.0, with the increase of pH value, the proliferation of V. mimicus increased first and then decreased with the strongest at pH 8.5; self-aggregation, biofilm formation and virulence of ECPs weakened first and then increased with the weakest power at pH 8.5 (P<0.05); swimming motility and protein mass concentration and cytotoxicity of ECPs showed a weakening trend, which pH 6.0 was significantly stronger than other pH value (P<0.05); in addition to the ECPs enzyme activities and hemolysis were fluctuated, which the strongest enzyme activity was at the pH 6.0 and the weakest enzyme activity at the pH 8.0; hemolytic was the strongest at pH 8.0 and the weakest at pH 8.5. Transcriptome analysis showed that: by comparing pH 7.0 and 8.5, the expression of genes related to ATP synthesis such as glycolysis pathway, TCA cycle, and oxidative phosphorylation was up-regulated in pH 8.5, while the expression of genes related to ADP synthesis such as purine synthesis and ribosomal subunit synthesis was down-regulated.

ConclusionpH has obvious influence on the V. mimicus infection-related phenotypes and ECPs characteristics, which may affect these related biological characteristics by regulating energy metabolism and membrane transport.