中文摘要：从某猪场分离到新型强毒力长尾病毒科噬菌体swi2，并分析了其生物学特性、基因组结构及感染相关特性。发现噬菌体swi2滴度高，为1.01 x 10（12）PFU/mL，对紫外线耐受性良好，并且在pH6-10范围内、温度低于50℃时保持稳定。一步生长分析显示，噬菌体swi2的潜伏期为25分钟，具有较大的感染复数（1000 PFU/细胞）。生物学特性表明，swi2具有良好的宿主感染性和有效的裂解活性。噬菌体swi2基因组由47611bp组成，G+C含量为46.50%。预测到89个ORF，其中只有18个具有已知功能。基因组中未发现毒力基因或耐药基因。对噬菌体swi2进行基因组序列比对发现，数据库中共有10个同源噬菌体，相似性较低（核苷酸同源性低于92.51%，查询覆盖率低于66%）。预测噬菌体swi2的宿主裂解相关基因由一个holin、两个细胞内溶素和Rz/Rz1等同物组成。抑菌活性实验表明，两种内溶素均能在体外和体内以-1 log单位自然降低宿主大肠杆菌51滴度，EDTA无明显的协同作用，holin对宿主细胞无溶解作用。本研究为开发治疗耐多药大肠杆菌感染的抗生素替代品提供了必要的信息。
外文摘要：The novel virulent Siphoviridae bacteriophage swi2 was isolated from a pig farm, and its biological characteristics, genome architecture, and infection-related properties were characterized. Phage swi2 has a high titer of 1.01 x 10(12) PFU/mL with good tolerance to UV rays and remains stable in the pH range of 6-10 and at temperatures less than 50 degrees C. One-step growth analysis revealed that phage swi2 had a 25 min latent period with a large burst size (1,000 PFU/cell). The biological characteristics indicated that swi2 had good host infectivity and effective lytic activities. The genome of phage swi2 is composed of 47,611 bp with a G + C content of 46.50%. Eighty-nine orfs were predicted, and only 18 of them have known functions. No virulence genes or drug resistance genes were found in the genome. Genome sequence comparison of phage swi2 showed that there were a total of 10 homologous phages in the database with low similarity (less than 92.51% nucleotide identity and 66% query coverage). The predicted host lysis-related genes of phage swi2 consist of one holin, two endolysins, and Rz/Rz1 equivalents. Antibacterial activity assays showed that both endolysins could naturally reduce the host Escherichia coli 51 titers by -1 log unit both in vitro and in vivo, EDTA showed no obvious synergistic action, and holin had no lytic effects on the host cell. These results provide necessary information for the development of antibiotic alternatives for the treatment of multidrug-resistant Escherichia coli infection.
外文关键词：bacteriophage swi2；biological and genomic character；endolysin；holing； antibacterial activity
作者：Sui, BR；Qi, X；Wang, XX；Ren, HY；Liu, WH；Zhang, C
作者单位：Qingdao Agr Univ
期刊名称：FRONTIERS IN MICROBIOLOGY
期刊影响因子：4.236
出版年份：2021
出版刊次：12
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