Stable Isotope Labeling by Amino Acids in Cell Culture (SILAC) Applied to Quantitative Proteomics of Vibrio parahaemolyticus under Cold Stress

Objective: The aim of this study was to conduct a comparative proteome quantitation of Vibrio parahaemolyticus in response to cold stress, demonstrating specifically characteristic changes at proteomic level, and to analyze the possible potential risks based on cold-stressed strains. Method: Comparative proteome quantitation analysis based on Stable Isotope Labeling by Amino Acid in Cell Culture (SILAC) is combined with high resolution mass spectrometry, which minimizes errors and contributes to the higher accuracy compared with chemical or label-free approaches. Results: A total of 1182 proteins were identified, among which 601 were quantified. Catalase/peroxidase HPI, aromatic amino acid aminotransferase and 16S rRNA methyltransferase were significantly upregulated in spite of the inconsistency of some proteins expression and its corresponding mRNA expression. Glutamine synthetase, asparagine synthetase and enzymes related to pentose phosphate pathway increased as well. Some proteins associated with glycolysis, tricarboxylic acid cycle, transcription and translation were downregulated. Some proteins related to DNA synthesis were almost unchanged. Conclusion: The results demonstrated that most upregulated proteins enhance the stress resistance and self-adaptation. We assume that there may be correlation between upregulation and potential risks on seafood. Most downregulated proteins contribute to energy conservation and self-protection in order to resist various negative stresses. This study provides information on specific differences of proteome and offers some new clues to the differentiation and analysis of V. parahaemolyticus under cold stress.