Stroeher U H, Jedani K E, Dredge B K, Morona R, Brown M H, Karageorgos L E, Albert M J, Manning P A
Department of Microbiology and Immunology, University of Adelaide, South Australia.
Proc Natl Acad Sci U S A. 1995 Oct 24;92(22):10374-8. doi: 10.1073/pnas.92.22.10374.
The recent emergence of a pathogenic new non-O1 serotype (O139) of Vibrio cholerae has led to numerous studies in an attempt to identify the origins of this new strain. Our studies indicate that O139 strains have clear differences in the surface polysaccharides when compared with O1 strains: the lipopolysaccharide can be described as semi-rough. Southern hybridization with the O1 rfb region demonstrates that O139 strains no longer contain any of the rfb genes required for the synthesis of the O1 O-antigen or its modification and also lack at least 6 kb of additional contiguous DNA. However, O139 strains have retained rfaD and have a single open reading frame closely related to three small open reading frames of the O1 rfb region. This region is closely related to the H-repeat of Escherichia coli and to the transposases of a number of insertion sequence elements and has all the features of an insertion sequence element that has been designated VcIS1. Transposon insertion mutants defective in O139 O-antigen (and capsule) biosynthesis map to the same fragment as VcIS1. Preliminary sequence data of complementing clones indicate that this DNA encodes a galactosyl-transferase and other enzymes for the utilization of galactose in polysaccharide biosynthesis. We propose a mechanism by which both the Ogawa serotype of O1 strains and the O139 serotype strains may have evolved.
霍乱弧菌一种致病性新非O1血清型（O139）的近期出现引发了众多研究，旨在确定这种新菌株的起源。我们的研究表明，与O1菌株相比，O139菌株在表面多糖方面存在明显差异：其脂多糖可描述为半粗糙型。用O1 rfb区域进行Southern杂交显示，O139菌株不再含有合成O1 O抗原或其修饰所需的任何rfb基因，并且还缺失至少6 kb的相邻额外DNA。然而，O139菌株保留了rfaD，并且有一个与O1 rfb区域的三个小开放阅读框密切相关的单一开放阅读框。该区域与大肠杆菌的H重复序列以及一些插入序列元件的转座酶密切相关，并且具有已被命名为VcIS1的插入序列元件的所有特征。在O139 O抗原（和荚膜）生物合成中存在缺陷的转座子插入突变体定位到与VcIS1相同的片段。互补克隆的初步序列数据表明，该DNA编码一种半乳糖基转移酶和多糖生物合成中利用半乳糖的其他酶。我们提出了一种O1菌株的小川血清型和O139血清型菌株可能进化的机制。
