Although Alteromonas is ubiquitous in the marine environment, very little is known about Alteromonas phages, with only ten, thus far, being isolated and reported on. In this study, a novel double-stranded DNA phage, Alteromonas phage P24, which infects Alteromonas macleodii, was isolated from the coastal waters off Qingdao. Alteromonas phage P24 has a siphoviral morphology, with an icosahedral head, 61 ± 1 nm in diameter, and a tail length of 105 ± 1 nm. Alteromonas phage P24 contains lipids. It has an optimal temperature and pH for growth of 20℃ and 5–7, respectively. A one-step growth curve shows a latent period of 55 min, a rise period of 65 min, and an average burst size of approximately 147 virions per cell. Alteromonas phage P24 has the genome of 46,945 bp with 43.80% GC content and 74 open reading frames (ORFs) without tRNA. The results of the phylogenetic tree, based on the mcp and terL genes, show that Alteromonas phage P24 is closely related to Aeromonas phage phiARM81ld. Meanwhile, phylogenetic analysis based on the whole genome of P24 indicates that it forms a unique viral sub-cluster within Siphoviridae. This study contributes to the understanding of the genomic characteristics and the virus-host interactions of Alteromonas phages.

中文翻译：

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一种新型海洋交替单胞菌噬菌体 P24 的表征和基因组分析

尽管交替单胞菌在海洋环境中无处不在，但对交替单胞菌噬菌体知之甚少，迄今为止只有十种被分离和报道。在这项研究中，从青岛近海海域分离出一种新型双链DNA噬菌体Alteromonas phage P24，它感染Alteromonas Macleodii。交替单胞菌噬菌体 P24 具有虹吸病毒形态，具有二十面体头部，直径为 61 ± 1 nm，尾长为 105 ± 1 nm。交替单胞菌噬菌体 P24 含有脂质。它的最适生长温度和pH分别为20℃和5-7。一步生长曲线显示潜伏期为 55 分钟，上升期为 65 分钟，每个细胞平均爆发大小约为 147 个病毒粒子。交替单胞菌噬菌体 P24 的基因组为 46,945 bp，GC 含量为 43.80%，74 个开放阅读框 (ORF) 不含 tRNA。基于 mcp 和 terL 基因的系统发育树结果表明，交替单胞菌噬菌体 P24 与气单胞菌噬菌体 phiARM81ld 密切相关。同时，基于 P24 全基因组的系统发育分析表明它在 Siphoviridae 内形成了一个独特的病毒亚群。这项研究有助于了解交替单胞菌噬菌体的基因组特征和病毒-宿主相互作用。