一株彭氏变形杆菌噬菌体phiP4-3生物学特性及基因组学研究

Biological Characteristics and Genomic Analysis of a Lytic Phage phiP4-3 Specific for Proteus penneri

背景:彭氏变形杆菌是重要的致病菌,其耐药菌株的出现给公共卫生和食品安全带来了严重威胁。噬菌体能杀死病原菌,具有替代抗生素的潜在能力。目的:以彭氏变形杆菌(Proteus penneri)为宿主菌,从淡水鱼肠道中分离得到一株烈性噬菌体phiP4-3,并对其生物学特性、基因组学和分类学进行了研究。方法:使用透射电子显微镜观察噬菌体的形态;通过一步生长曲线和抑菌曲线,分析噬菌体的杀菌效果;通过基因组测序、注释和比较基因组学分析噬菌体的功能和分类。结果:通过透射电子显微镜观察,phiP4-3噬菌体头部直径为98.83 nm,可伸缩尾部长度为55.35 nm。一步生长曲线结果显示,该噬菌体的潜伏时间约为25 min,每个感染中心释放的噬菌体数量约为17 PFU。抑菌曲线结果显示,噬菌体phiP4-3能有效抑制宿主菌生长。基因组测序组装结果显示,噬菌体phiP4-3的基因组长度为167 849 bp, GC含量为31.5%。使用软件对基因组进行注释,发现噬菌体phiP4-3的基因组上共编码270个ORF和8个tRNA基因。综合比较基因组学、分类学及国际病毒分类委员会(ICTV)的分类结果,将其归类为Straboviridae科Bragavirus属病毒。结论:分离得到一株新彭氏变形杆菌噬菌体,并对其生物学特性和基因组进行了分析,为噬菌体在公共卫生和食品安全中的应用提供了理论依据。

Background:Proteus penneri is an important bacterial pathogen,and the emergence of the multidrug resistant strains poses a major threat to public health and food safety.Phages can kill the host bacterial pathogens and are possible alternatives to conventional antibiotics.Objective:In this study,a lytic phage phiP4-3 was isolated from the gastrointestinal contents of freshwater fish using a Proteus penneri strain as an indicator.Phage phiP4-3 was investigated for biological characteristics,genomics,and taxonomy.Methods:The morphology of phiP4-3 was analyzed by transmission electron microscope(TEM);the bactericidal effect of phage was analyzed by one-step growth curve and bacteriostatic curve;the function and classification of phages were analyzed by genome sequencing and comparative genomics.Results:Through TEM observation,the head diameter of phiP4-3 bacteriophage is 98.83 nm,and the retractable tail length is 55.35 nm.The results of the one-step growth curve show that the incubation time of the phage is about 25 min,and its burst size was about 17 PFU/infection center.The antibacterial curve results showed that phiP4-3 can effectively inhibit the growth of the host.The genome sequencing assembly results showed that the genome length of phiP4-3 was 167849 bp,with a GC content of 31.5%.Bioinformatic tools reveal that the phiP4-3 genome has 270 ORFs and 8 tRNA genes,and no antibiotic resistance genes or virulence genes were identified.Based on the classification results of comparative genomics,taxonomy,and ICTV,the phiP4-3 can be classified in the family Straboviridae and genus Bragavirus.Conclusion:A phage from Proteus penneri was isolated,and its biological characteristics and genomics were analyzed,providing a theoretical basis for the application of bacteriophage in public health and food safety.