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Survival strategy of intracellular Rhodococcus equi : the role of virulence plasmid.

细胞内马红球菌的生存策略：毒力质粒的作用。

基本信息

批准号：
12460140
负责人：
TAKAI Shinji
金额：
$ 9.22万
依托单位：
Kitasato University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12460140/
关键词：
Rhodococcu equi virulence plasmid DNA sequence pathogenicity intracellular bacteri macrophage horse virulence 病原性プラミスド Rhodococcus equi 食菌抵抗性

项目摘要

At least three virulence levels of Rhodococcus equi have been identified : virulence, intermediate virulence, and avirulence. Virulent R. equi is characterized by the presence of virulence-associated 15-to 17-kDa antigens (VapA), virulence plasmid DNA of 85 to 90 kb, and suppurative pneumonia in foals (mouse LD_<50>=10^6). R. equi strains of intermediate virulence are identified by a virulence associated 20-kDa antigen (VapB) and virulence plasmid DNA of 79 to 100 kb and are found in the submaxillary lymph nodes of pigs (mouse LD_<50>=10^7). To analyze the difference of virulence levels in R. equi, the virulence plasmid of the R. equi strain A3 of intermediate virulence (pREA3) was sequenced and compared with the DNA sequence of the virulence plasmid (p33701). pREA3 was 79,288 by and the plasmid encoded 71 open reading frames (ORFs). Of the 71 ORFs, 52 were found to be almost identical to those in the virulence plasmid (p33701). pREA3 also has a pathogenicity island containing 5 new virulence-associated protein (vap) genes [vapI, vapJ (2 copies), vapK, and vapL] located upstream of vapB. There was extensive homology in the region except the pathogenicity island between p33701 and pREA3. These results suggest that the difference in the structure and function of the pathogenicity islands between p33701 and pREA3 might be responsible for the difference in virulence levels of R. equi.

马红球菌至少有三种毒力水平：毒力、中等毒力和无毒力。维尤恩特河马的特征是存在毒力相关的15至17 kDa抗原（VapA）、85至90 kb的毒力质粒DNA和马驹化脓性肺炎（小鼠LD_<50>=10^6）。R.中等毒力的马属菌株通过毒力相关的20 kDa抗原（VapB）和79 ~ 100 kb的毒力质粒DNA鉴定，并在猪的颌下淋巴结中发现（小鼠LD_<50>=10^7）。分析了不同菌株毒力水平的差异。equi的毒力质粒。对中等毒力马属A3株（pREA 3）进行了DNA序列测定，并与毒力质粒（p33701）的DNA序列进行了比较。pREA 3基因全长79，288 bp，编码71个开放阅读框（ORF）。在71个ORF中，发现52个与毒力质粒（p33701）中的ORF几乎相同。pREA 3还具有致病性岛，其含有位于vapB上游的5个新的毒力相关蛋白（vap）基因[vapI、vapJ（2个拷贝）、vapK和vapL]。p33701与pREA 3之间除毒力岛外，其余区域均具有广泛的同源性。这些结果表明，p33701和pREA 3致病岛结构和功能的差异可能是导致致病力差异的原因。等。