Yinghui Jiang

Visualized analysis of cellular fatty acid profiles of Vibrio parahaemolyticus strains under cold stress

Vibrio parahaemolyticus is a common foodborne bacterial pathogen, which survives in cold environments and is sometimes difficult to culture. Fatty acid analysis under cold stress was conducted for several V. parahaemolyticus strains using gas chromatography/mass spectrometry, and the results were compared with those of the controls. All the fatty acid profiles obtained were visualized by multidimensional scaling (MDS) and self-organized map (SOM). It was observed that the fatty acid profiles of V. parahaemolyticus substantially changed under cold stress. The percentage of methyl palmitate remarkably decreased and that of methyl palmitoleate (except for two strains) and methyl oleate increased. These findings demonstrate the role of fatty acids in cold stress. The changes in the fatty acid profiles illustrated by MDS and SOM could differentiate strains under cold stress from the controls and can potentially lead to a method of detecting injured cold-stressed V. parahaemolyticus.

Proteomic analysis of Vibrio metschnikovii under cold stress using a quadrupole Orbitrap mass spectrometer.

Vibrio metschnikovii is a food-borne pathogen found in seafood worldwide. We studied the global proteome responses of V. metschnikovii under cold stress by nano-flow ultra-high-performance liquid chromatography coupled to a quadrupole Orbitrap mass spectrometer. A total of 2066 proteins were identified, among which 288 were significantly upregulated and 572 were downregulated. Functional categorization of these proteins revealed distinct differences between cold-stressed and control cells. Quantitative reverse transcription polymerase chain reaction analysis was also performed to determine the mRNA expression levels of seventeen cold stress-related genes. The results of this study should improve our understanding of the metabolic activities of cold-adapted bacteria and will facilitate a better systems-based understanding of V. metschnikovii.

Strain-level visualized analysis of cold-stressed Vibrio parahaemolyticus based on MALDI-TOF mass fingerprinting.

In this study, strain-level visualized analysis of cold-stressed Vibrio parahaemolyticus based on matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass fingerprinting was investigated. All the peptide mass fingerprinting profiles obtained were analyzed by self-organized map (SOM) and cluster analysis. Our results showed that the peptide mass fingerprinting profiles of V. parahaemolyticus substantially changed under cold stress at strain level. The cold-stressed V. parahaemolyticus strains were distributed to 14 neurons by SOM classification, almost totally different from the controls. This is the first time that so many strains had been chosen to study bacterial cold stress responses, which can help promote an overall understanding to stress responses of cold-stressed strains.