Inhibition effect and transcriptome analysis of Gan Dan oral liquid against Vibrio parahaemolyticus

Abstract:

Objective To investigate the in vitro inhibitory activity of Gan Dan oral liquid (GD) against Vibrio parahaemolyticus and decipher the inhibition mechanism at the transcriptome level.Methods The in vitro inhibitory activity of GD against V. parahaemolyticus was evaluated based on the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and growth curve. Scanning electron microscopy and transmission electron microscopy were employed to analyze the effect of GD on the cellular structure of V. parahaemolyticus. Transcriptome sequencing coupled with bioinformatics methods were employed to investigate the effect of GD at 1/4MIC on the transcriptome of V. parahaemolyticus, and the obtained results were examined by real-time quantitative reverse transcription PCR (RT-qPCR).Results GD exhibited high in vitro inhibitory activity against V. parahaemolyticus, with the MIC and MBC of 7.6 mg/mL and 15.2 mg/mL, respectively. The GD treatment at a concentration of 1/4MIC disrupted the cell wall integrity and increased cell membrane permeability of the pathogen, and leading to the leakage of intracellular macromolecules. The results of transcriptome sequencing showed that GD treatment significantly altered the transcriptome profile of V. parahaemolyticus, resulting in significant upregulation of 1 074 genes and significant downregulation of 1 179 genes. The downregulated genes were mainly enriched in pathways related to the synthesis of inosinate and ribonucleoside, whereas the upregulated genes were primarily categorized into pathways associated with transcription factor activity and cell wall synthesis.Conclusion GD may inhibit V. parahaemolyticus by disrupting cell structure and inhibiting cellular energy metabolism and biosynthesis.