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Volume 9
Journal of Analytical & Bioanalytical Techniques
Mass Spectra & Analytika 2018
September 19-20, 2018
September 19-20, 2018 Singapore
World Congress on
Mass Spectrometry and Analytical Techniques
Hongshun Yang, J Anal Bioanal Tech 2018, Volume 9
DOI: 10.4172/2155-9872-C2-030
Metabolic analysis and transcriptomic response of
Escherichia coli
O157:H7 treated with
electrolyzed water and mild heat
Hongshun Yang
National University of Singapore, Singapore
M
etabolite levels and gene expression in bacteria offer significant insights into the response of bacteria to disinfection
intervention. The purpose of this study was to explore the possible mechanisms underlying the metabolic and
transcriptomic changes of
Escherichia coli
O157:H7 in the response to Electrolyzed Water (EW) and mild heat treatments. The
oxidant-sensitive probe 2’, 7-Dichlorodihydrofluorescein Diacetate (H
2
DCFDA) was used to assess the intracellular reactive
oxidative species. The metabolomic changes were investigated by UPLC-QToF-MS coupled with multivariate analysis. EW
(4 mg/L free available chlorine) combined with heat treatment at 50 °C resulted in 2.31 log CFU/mL reductions of
E. coli
O157:H7. The fluorescence intensity of EW at 50 °C showed the greatest and was 10 times greater than the control group. The
decreased ribose-5-phosphate level strongly indicated affected nucleotide biosynthesis, which was consistent with nucleotide
level in the E. coli O157:H7 cells in response to EW and heat treatments. A 50 fold increase in heat shock regulatory gene rpoH
expression was found in 50 °C group and combined treatment group compared to the control group, while for EW group the
gene expression remained unchanged. However, when treated with EW at 50 °C almost all the gene expressions (except
rpoH
)
were dampened with about 0.024-, 0.286- fold decrease for
udk
(encoding uridine kinase) and
gadA
(encoding glutamate
decarboxylase alpha), respectively, as compared to control group. The results demonstrate a synergistic effect of EW and heat
treatment on inactivating
E. coli
O157:H7.
Biography
Hongshun Yang has completed his PhD from the University of Minnesota and Postdoctoral studies from University of Maryland College Park. He has published
more than 90 papers in reputed journals and has been serving as an Editorial Board Member of LWT-Food Science and Technology.
chmynghs@nus.edu.sg