Characterization of Vibrio cholerae O1 antigen as the bacteriophage K139 receptor and identification of IS1004 insertions aborting O1 antigen biosynthesis
Characterization of Vibrio cholerae O1 antigen as the bacteriophage K139 receptor and identification of IS1004 insertions aborting O1 antigen biosynthesis
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DOI：
10.1128/jb.182.18.5097-5104.2000
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发表时间：
2000-09-01
影响因子：
3.2
通讯作者：
Reidl, J
中科院分区：
文献类型：
--
作者：
Nesper, J;Kapfhammer, D;Reidl, J
噬菌体K139是O1霍乱弧菌的一种温和噬菌体。用不同O1血清型和生物型的纯化脂多糖（LPS）进行的噬菌体结合研究表明，O1抗原作为噬菌体受体。此外，用噬菌体K139强毒分离株筛选了抗O1 El Tor噬菌体的菌株，对这些自发抗噬菌体突变株的LPS分析表明，它们大多合成不完整的LPS分子，由缺陷的O1抗原或核心寡糖组成。通过应用噬菌体结合研究，有可能区分受体突变体和可能导致噬菌体感染后期步骤流产的突变。此外，我们研究了O1阴性菌株的遗传特性，通过Southern杂交与探针特异性O抗原生物合成簇（rfb区域）。研究的两个O1抗原阴性突变体显示元件IS 1004插入到rfb基因簇中。用正常人血清处理一个wbeW：：IS1004血清敏感突变体，我们发现几个存活者显示精确的IS1004切除，恢复O抗原生物合成和血清抗性。通过筛选噬菌体耐药性和对非溶原性菌株进行LPS分析，对临床分离株进行调查，结果发现O1抗原呈递减少的菌株。该菌株在小鼠小肠定殖的能力显著降低。
Bacteriophage K139 was recently characterized as a temperate phage of O1 Vibrio cholerae, In this study we have determined the phage adsorption site on the bacterial cell surface. Phage-binding studies with purified lipopolysaccharide (LPS) of different O1 serotypes and biotypes revealed that the O1 antigen serves as the phage receptor. In addition, phage-resistant O1 El Tor strains were screened by using a virulent isolate of phage K139, Analysis of the LPS of such spontaneous phage-resistant mutants revealed that most of them synthesize incomplete LPS molecules, composed of either defective O1 antigen or core oligosaccharide. By applying phage-binding studies, it was possible to distinguish between receptor mutants and mutations which probably caused abortion of later steps of phage infection. Furthermore, we investigated the genetic nature of O1-negative strains by Southern hybridization with probes specific for the O antigen biosynthesis cluster (rfb region). Two of the investigated O1 antigen-negative mutants revealed insertions of element IS1004 into the rfb gene cluster. Treating one wbeW::IS1004 serum-sensitive mutant with normal human serum, we found that several survivors showed precise excision of IS1004, restoring O antigen biosynthesis and serum resistance. Investigation of clinical isolates by screening for phage resistance and performing LPS analysis of nonlysogenic strains led to the identification of a strain with decreased O1 antigen presentation. This strain had a significant reduction in its ability to colonize the mouse small intestine.