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Research On Ozone Inactivation Mechanism Of Vibrio Parahaemolyticus

Posted on:2014-08-24Degree:MasterType:Thesis
Country:ChinaCandidate:M S GaoFull Text:PDF
GTID:2250330428957296Subject:Food Science and Engineering
Abstract/Summary:PDF Full Text Request
Vibrio parahaemolyticus is often found on the surface of seafood, and is well-recognized as a primary cause of food-borne disease in our country. The most common syndrome caused by this organism is acute gastroenteritis, the symptoms includes abdominal pain, vomiting, dehydration and even death. Ozone is a kind of efficient and environmental protectional chemical bactericide, which has been widely applied in food processing, however, its sterilization effect on V. parahaemolyticus has not been reported.In this paper, V. parahaemolyticus was taken as the research object. In order to explore the mechanism of ozone sterilization, the changes of cell wall and membrane, intracellular macromolecular substances and genetic material in V. parahaemolyticus exposed to ozone water were analyzed. Afterwards, the high-throughput RNA sequencing technology (RNS-Seq) was utilized to interrogate the transcriptome of V. parahaemolyticus in response to ozone stress with different concentration, and the differentially expressed genes and its annotation were compared and analyzed.The results were as follows:1. Ozone has strong bactericidal effect on V. parahaemolyticus. The bacteria (10cfu/mL) were totally killed in the ozone water treatment (1.2mg/L) within1min. From the quadratic models developed for bacterial survival and subsequent ANOVA test using Design-Expert7.0.0, the concentration of ozone water was found to be the most influential factor (P<0.01), while the time of treatment was also significant (P<0.05).2. With the increase in the concentration of ozone water over the range0-1.2mg/L, the activity of Na+/K+-ATPase and antioxidant enzyme were decreased and genomic DNA and total RNA were degraded. The results suggested that destruction of cell wall and membrane, accumulation of strong oxidation products caused by the inactivation of antioxidant enzymes and the irreversible damage of genetic substances finally lead to the death of V. parahaemolyticus.3. From the result of COG-category and GO functional enrichment analysis of the differentially expressed genes in response to ozone stress with different concentration, when treated with ozone water of low concentration (0.1mg/L), V. parahaemolyticus mainly enhanced the transcription level and promoting the metabolism to weaken the effect of oxidation. However, when exposed to ozone water of high concentration (1.0mg/L), the decline of the gene expression lever, which relating with amino acid, ion transport and defense, resulted in the inhibition of aforementioned defense mechanism, and ultimately caused cell death.
Keywords/Search Tags:ozone water, Vibrio parahaemolyticus, RNA-Seq, inactivation mechanism
PDF Full Text Request
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