摘要 大肠杆菌O157∶H7是一种常见的能严重威胁公共卫生安全的食源性致病菌,噬菌体及其内溶酶、穿孔素是新型的抑菌剂。该文利用十聚体寡核苷酸随机引物初步鉴定了噬菌体EC-p9;应用PCR技术获得该噬菌体的内溶酶Lys 9和穿孔素Hol 9的基因;利用生物学信息预测了这2种蛋白的特性;通过大肠杆菌表达体系表达了这2种蛋白。结果表明,噬菌体EC-p9是dsDNA肌尾科噬菌体,具有“穿孔素-内溶酶”裂解体系。内溶酶Lys 9是一种不含跨膜结构的肽聚糖水解酶。穿孔素Hol 9是Ⅲ型穿孔素,仅有1个跨膜结构。内溶酶Lys 9和穿孔素Hol 9都能通过大肠杆菌表达体系成功表达,但穿孔素Hol 9的表达会对大肠杆菌BL21(DE3)产生毒害作用,导致表达量较少。最终获得了质量浓度为2.49 g/L的内溶酶Lys 9和0.95 g/L的穿孔素Hol 9。该研究为开展内溶酶Lys 9和穿孔素Hol 9的抑菌能力以及噬菌体EC-p9的裂解体系的研究奠定了基础。 Escherichia coli O157∶H7 is a common foodborne pathogen that severely threatens public health.Phage,endolysin and holin are new bacteriostatic agents.In this study,phage EC-p9 was identified by random primer for decammeric oligonucleotide,genes of endolysin Lys 9 and holin Hol 9 of the phage were obtained through PCR,properties of the two proteins were predicted through in-silico analysis,and the two proteins were expressed by E.coli.The results indicated that phage EC-p9 was dsDNA phage with a“holin-endolysin”lysis system.Endolysin Lys 9 was a peptidoglycan hydrolase without a transmembrane structure.Holin Hol 9 was a type III holin with only one transmembrane structure.Endolysin Lys 9 and holin Hol 9 were successfully expressed in E.coli BL21(DE3),with yield of 2.49 and 0.95 g/L,respectively.only limited amount of holin Hol 9 was obtained due to its toxic effect on E.coli.The results laid a foundation for research of the bacteriostatic ability of endolysin Lys 9 and holin Hol 9,and also for investigation of the lysis system of phage EC-p9.
机构地区 西南大学食品科学学院
出处 《食品与发酵工业》 CAS CSCD 北大核心 2021年第9期107-113,共7页 Food and Fermentation Industries
基金 国家自然科学基金面上项目(32072322) 重庆市技术创新与应用发展项目面上项目(cstc2019jscx-msxmX0348) 重庆市留学人员创业创新计划优秀项目(cx2019017) 中央高校基本科研业务费重点项目(XDJK2020B043)。
分类号 S85 [农业科学—兽医学]
