Cai Lanlan, Tian Yuan, Li Ziqiang, Yang Yunlan, Ai Chunxiang, Zhang Rui
State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
Department of Ocean Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China.
Front Microbiol. 2023 Jun 2;14:1191157. doi: 10.3389/fmicb.2023.1191157. eCollection 2023.
Vibriosis is one of the most common bacterial diseases that cause high rates of mortality and considerable economic losses in aquaculture. Phage therapy has been considered as a promising alternative method to antibiotics in the biocontrol of infectious diseases. Genome sequencing and characterization of the phage candidates are prerequisites before field applications to ensure environmental safety. In this study, a lytic phage, named vB_VhaS-R18L (R18L), was isolated from the coastal seawater of Dongshan Island, China. The phage was characterized in terms of morphology, genetic content, infection kinetics, lytic profile, and virion stability. Transmission electronic microscopy indicated that R18L is siphovirus-like, comprising an icosahedral head (diameter 88.6 ± 2.2 nm) and a long noncontractile tail (225 × 11 nm). Genome analysis indicated R18L to be a double-stranded DNA virus with a genome size of 80,965 bp and a G + C content of 44.96%. No genes that encode known toxins or genes implicated in lysogeny control were found in R18L. A one-step growth experiment showed that R18L had a latent period of approximately 40 min and a burst size of 54 phage particles per infected cell. R18L showed lytic activity against a wide range of at least five species (, , , , and ). R18L was relatively stable at pH 6-11 and at temperatures ranging from 4°C to 50°C. The broad lytic activity across species and the stability in the environment make R18L a potential candidate for phage therapy in controlling vibriosis in aquaculture systems.
弧菌病是最常见的细菌性疾病之一，在水产养殖中会导致高死亡率和巨大的经济损失。在传染病的生物防治中，噬菌体疗法被认为是一种有前景的替代抗生素的方法。在进行现场应用之前，对候选噬菌体进行基因组测序和特性分析是确保环境安全的前提条件。在本研究中，从中国东山岛的沿海海水中分离出一种裂解性噬菌体，命名为vB_VhaS-R18L（R18L）。对该噬菌体的形态、遗传内容、感染动力学、裂解谱和病毒体稳定性进行了表征。透射电子显微镜显示R18L类似肌尾噬菌体，由一个二十面体头部（直径88.6±2.2nm）和一条长的非收缩性尾部（225×11nm）组成。基因组分析表明R18L是一种双链DNA病毒，基因组大小为80,965bp，G+C含量为44.96%。在R18L中未发现编码已知毒素的基因或与溶原性控制有关的基因。一步生长实验表明，R18L的潜伏期约为40分钟，每个感染细胞的爆发量为54个噬菌体颗粒。R18L对至少五种弧菌（、、、和）表现出裂解活性。R18L在pH值为6-11以及温度在4°C至50°C范围内相对稳定。R18L对多种弧菌的广泛裂解活性以及在环境中的稳定性使其成为水产养殖系统中控制弧菌病的噬菌体疗法的潜在候选者。
