本研究通过双层平板法从湖水中分离、纯化出一株大肠杆菌O157:H7烈性噬菌体,并命名为SF08.对其生物学特性、基因组序列及在即食鸡爪中的抑菌效果进行分析.结果表明,SF08由长约124 nm的可收缩尾巴和直径约76 nm的多面体头部组成.最佳感染复数(Multiplicity of Infection,MOI)为0.01;潜伏期为20 min,裂解期为20～110 min,爆发量为66 PFU/cell;在pH 3～12和30～70℃条件下能保持较高的活性.基因组全长59704 bp,G+C含量为56.52%,共有72个开放阅读框(ORF).SF08在4℃下可以极显著地抑制即食鸡爪中模拟污染的大肠杆菌O157:H7(P＜0.01).本研究表明SF08具有较好的生物学特性及安全性,为后续研发和制备天然杀菌剂提供理论基础和参考.
Isolation,Characterization and Application in Food of Escherichia coli O157:H7 Virulent Bacteriophage SF08
In this study,a virulent bacteriophage of Escherichia coli O157:H7 was isolated and purified from lake water by double-layer agar plate method,and named SF08.The biological characteristics,genome sequence and antibacterial effect of SF08 in ready-to-eat chicken feet were analyzed.The results showed that SF08 was composed of a retractable tail about 124 nm long and a polyhedral head about 76 nm diameter.The optimal multiplicity of infection(MOI)was 0.01.The latent period was 20 min,the lysis period was 20～110 min,and the burst size was 66 PFU/cell.SF08 could maintain high activity under the range of pH(3～12)and temperatures(30～70℃).The total length of the genome was 59704 bp,the G+C content was 56.52%,and there were 72 open reading frames(ORFs).SF08 could significantly inhibit simulated contaminated Escherichia coli O157:H7 in ready-to-eat chicken feet at 4℃(P＜0.01).This study shows that SF08 has good biological characteristics and safety,which provides a theoretical basis and reference for the subsequent development and preparation of Escherichia coli O157:H7 natural fungicides.
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