摘要
研究牛肉生产和销售过程中沙门氏菌诱导耐酸响应(acid tolerance response,ATR)的存在程度及其产生机制。探究微酸诱导、双组分基因敲除、低温长期贮藏对沙门氏菌耐酸能力的影响,同时借助λRed同源重组、实时聚合酶链式反应(real-time polymerase chain reaction,real-time PCR)及氨基酸添加实验探索菌株耐酸性产生的内在机理。结果表明,微酸诱导能够显著增强沙门氏菌的耐酸能力(P<0.05),并且ATR一旦形成,在牛肉低温贮藏(4℃)的过程中至少可以维持7 d,对食品安全有极大危害。牛肉培养基作为微酸的细菌生长介质,在低温下其本身并不能引发沙门氏菌产生ATR,说明低温处理可能是抑制沙门氏菌ATR的重要方法。real-time PCR和氨基酸添加实验表明,沙门氏菌的双组分系统PhoP/PhoQ和PmrA/PmrB均参与酸性环境的感知,并能通过调控精氨酸脱羧和赖氨酸脱羧系统提高菌株的耐酸性,这从氨基酸代谢角度解释了沙门氏菌诱导ATR的产生机制,同时也揭示了食品基质提升微生物耐酸性这一表观现象的内在机理。
The influence of acid induction,two-component regulatory systems and long-term low-temperature storage on the formation of acid tolerance response(ATR)was evaluated,and the mechanism of ATR formation was elucidated by using the λ Red recombination system,real-time polymerase chain reaction(real-time PCR)and amino acid addition experiments.The results showed that mild acid induction significantly enhanced the acid tolerance of Salmonella(P<0.05),and once induced,it could be maintained for at least 1 week at 4℃,posing a great threat to food safety.As a mildly acidic incubation medium,beef did not induce ATR at 4℃,indicating that low-temperature treatment may be an important method to inhibit ATR in Salmonella typhimurium.Real-time PCR and amino acid addition experiments showed that PhoP/PhoQ and PmrA/PmrB were involved in the perception of the acidic environment,improving bacterial acid resistance by regulating the arginine decarboxylation and lysine decarboxylation systems.This explains the mechanism of ATR formation from the perspective of amino acid metabolism,which may also reveal an explanation of why food substrates can enhance the acid resistance of some bacteria.
作者
郎晨晓
张一敏
朱立贤
梁荣蓉
毛衍伟
杨啸吟
韩广星
罗欣
董鹏程
LANG Chenxiao;ZHANG Yimin;ZHU Lixian;LIANG Rongrong;MAO Yanwei;YANG Xiaoyin;HAN Guangxing;LUO Xin;DONG Pengcheng(College of Food Science and Engineering,Shandong Agricultural University,Tai’an 271018,China;National Beef Cattle Industrial Technology System,Linyi Station,Linyi 276000,China)
出处
《食品科学》
EI
CAS
CSCD
北大核心
2021年第6期68-74,共7页
Food Science
基金
国家自然科学基金青年科学基金项目(31801609)
现代农业产业技术体系建设专项(CARS-37)
山东省现代农业产业技术体系牛产业创新团队项目(SDAIT-09-09)
山东省自然科学基金博士基金项目(ZR2017BC064)。
