Nguyen Doreen, Ely Bert
Department of Biological Sciences, University of South Carolina, Columbia, SC, 29208, USA.
Department of Microbiology, University of Georgia, Athens, GA, USA.
Curr Microbiol. 2018 Jun;75(6):760-765. doi: 10.1007/s00284-018-1445-9. Epub 2018 Feb 8.
Bacteriophages remain an understudied component of bacterial communities. Therefore, our laboratory has initiated an effort to isolate large numbers of bacteriophages that infect Caulobacter crescentus to provide an estimate of the diversity of bacteriophages that infect this common environmental bacterium. The majority of the new isolates are phicbkviruses, a genus of giant viruses that appear to be Caulobacter specific. However, we have also isolated several Podoviruses with icosahedral heads and small tails. One of these Podoviruses, designated Lullwater, is similar to two previously isolated Caulobacter phages, Cd1 and Percy. All three have genomes that are approximately 45 kb and contain approximately 30 genes. The gene order is conserved among the three genomes with one of the genes coding for a DNA polymerase that has homology to the family of T7 DNA polymerases. Phylogenetic trees based on either the DNA polymerase or the RNA polymerase amino acid sequences suggests that the three phages represent a new branch of the T7virus tree. Based on these similarities, we concluded that Cd1, Lullwater, and Percy comprise a new group in the T7virus genus.
噬菌体仍然是细菌群落中一个研究不足的组成部分。因此，我们实验室已着手努力分离大量感染新月柄杆菌的噬菌体，以评估感染这种常见环境细菌的噬菌体的多样性。大多数新分离株是噬柄杆菌病毒，这是一类似乎对柄杆菌具有特异性的巨型病毒。然而，我们也分离出了几种具有二十面体头部和小尾巴的短尾病毒。其中一种短尾病毒名为卢尔沃特，与之前分离出的两种柄杆菌噬菌体Cd1和珀西相似。这三种噬菌体的基因组大小均约为45 kb，且都含有约30个基因。这三个基因组中的基因顺序是保守的，其中一个基因编码一种与T7 DNA聚合酶家族具有同源性的DNA聚合酶。基于DNA聚合酶或RNA聚合酶氨基酸序列构建的系统发育树表明，这三种噬菌体代表了T7病毒树的一个新分支。基于这些相似性，我们得出结论，Cd1、卢尔沃特和珀西在T7病毒属中构成一个新的组。
