Two T7-like Bacteriophages, K5-2 and K5-4, Each Encodes Two Capsule Depolymerases: Isolation and Functional Characterization.
Two T7-like Bacteriophages, K5-2 and K5-4, Each Encodes Two Capsule Depolymerases: Isolation and Functional Characterization.
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DOI：
10.1038/s41598-017-04644-2
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发表时间：
2017-07-04
影响因子：
4.6
通讯作者：
Wang JT
中科院分区：
文献类型：
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作者：
Hsieh PF;Lin HH;Lin TL;Chen YY;Wang JT
分离并鉴定了两种克雷伯氏菌噬菌体K5-2和K5-4，它们能够感染克雷伯氏菌菌株的K30/K69和K5或K8和K5型荚膜并在其上生长。每个噬菌体含有两个开放阅读框（ORF），分别编码两个推定的荚膜解聚酶。第一个ORF编码尾丝蛋白，具有K30/K69解聚酶和K8解聚酶活性。第二个ORF编码的假设蛋白质，其氨基酸序列几乎相同，并具有K5解聚酶活性。酶处理的荚膜多糖（CPS）的阿辛蓝染色显示纯化的解聚酶可以在体外切割纯化的克雷伯氏菌CPS并释放单糖。荚膜K5缺失突变体不被任一噬菌体裂解，表明荚膜是噬菌体感染所必需的。当将克雷伯氏菌菌株与β-内酰胺酶孵育而不是与纯化的解聚酶孵育时，观察到细菌杀伤。用K5-4噬菌体治疗显著增加了感染克雷伯氏菌的小鼠的存活率。pneumoniae K5菌株。总之，表征了两种双重宿主特异性克雷伯氏菌及其尾刺表现出荚膜解聚酶活性。每种噬菌体和噬菌体编码的解聚酶对荚膜型K30/K69、K8或K5具有特异性，可用于K.肺炎感染。
Two Klebsiella bacteriophages K5-2 and K5-4, which are able to infect and grow on either capsular types K30/K69 and K5 or K8 and K5 of Klebsiella strains, were isolated and characterized. Each phage contained two open reading frames (ORFs), which encoded two putative capsule depolymerases, respectively. The first ORF encoded tail fiber proteins, which have K30/K69 depolymerase and K8 depolymerase activities. The second ORF encoded hypothetical proteins, which are almost identical in amino acid sequences, and have K5 depolymerase activity. Alcian blue staining of enzyme-treated capsular polysaccharides (CPS) showed that purified depolymerases can cleave purified Klebsiella CPS in vitro and liberate monosaccharaides. Capsule K5 deletion mutants were not lysed by either phage, suggesting that the capsule was essential for phage infection. Bacterial killing was observed when incubated Klebsiella strains with phages but not with purified depolymerases. Treatment with the K5-4 phage significantly increased the survival of mice infected with a K. pneumoniae K5 strain. In conclusion, two dual host-specific Klebsiella phages and their tailspikes exhibit capsule depolymerase activity were characterized. Each phage and phage-encoded depolymerase has specificity for capsular type K30/K69, K8 or K5, and could be used for the typing and treatment of K. pneumoniae infection.