• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Infection and immunity >Association of Actinobacillus pleuropneumoniae Capsular Polysaccharide with Virulence in Pigs
【24h】

Association of Actinobacillus pleuropneumoniae Capsular Polysaccharide with Virulence in Pigs

机译：胸膜肺炎放线杆菌荚膜多糖与猪中毒力的关系

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The capsular polysaccharide (CP) of Actinobacillus pleuropneumoniae is required for virulence of the bacteria in swine. However, a molecular investigation of whether the type or quantity of CP affects A. pleuropneumoniae virulence has not been reported. To initiate this investigation, a DNA region downstream of conserved genes required for CP export in A. pleuropneumoniae serotype 1 was cloned and sequenced. Three open reading frames, designated cps1A, cps1B, and cps1C, were identified that had amino acid homology to bacterial carbohydrate biosynthesis genes. A kanamycin resistance cassette (Kanr) was inserted into a 750-bp deletion spanning cps1AB or into a 512-bp deletion in cps1B only, and the constructs were cloned in a suicide vector. The Kanr gene was then transferred into the chromosome of strain 4074 by homologous recombination to produce strain 4074Δcps1N and strain 4074Δcps1B, respectively. Strain 4074Δcps1N produced no detectable CP, but strain 4074Δcps1B made 15% of the serotype 1 CP made by the parent strain, 4074, as determined by enzyme-linked immunosorbent assay and precipitation of free CP. The cps1ABC genes of strain 4074 and the cps5ABC and cps5ABCDE genes of serotype 5a strain J45 were cloned into the shuttle vector pLS88 and electroporated into 4074Δcps1N to produce 4074Δcps1N(pABcps101), 4074Δcps1N(pJMLcps53), and 4074Δcps1N(pABcps55), respectively. Strain 4074Δcps1N(pABcps101) produced about 33% of the serotype 1 CP produced by strain 4074. Strains 4074Δcps1N(pJMLcps53) and 4074Δcps1N(pABcps55) produced serotype 5a CP in similar quantity or in fourfold excess, respectively, to that produced by strain 4074. With intratracheal challenge in pigs at similar dosages, the order of virulence of strains producing serotype 1 CP (assessed by mortality, lung consolidation, hemorrhage, and fibrinous pleuritis) was the following: strain 4074 > strain 4074Δcps1N(pABcps101) ≥ strain 4074Δcps1N > strain 4074Δcps1B. Strain 4074Δcps1N(pJMLcps53) was less virulent than strain 4074Δcps1N(pABcps55). However, both strains produced serotype 5a CP in similar or greater quantities than was observed for production of serotype 1 CP by the parent strain, 4074, but were less virulent than the parent strain. Therefore, the amount of serotype 1 or 5a CP produced by isogenic strains of A. pleuropneumoniae correlated with the virulence of the bacteria in pigs. However, virulence was also influenced by the type of CP produced or by its mechanism of expression.
机译：猪胸膜肺炎放线杆菌的荚膜多糖（CP）是猪中细菌毒性的必需物质。但是，有关CP的类型或数量是否影响 A的分子研究。尚未报告胸膜肺炎毒力。为了启动这项研究，CP出口 A所需的保守基因下游的DNA区域。克隆并鉴定了肺炎胸膜肺炎血清型1。确定了三个开放阅读框，分别命名为 cps1A，cps1B，和 cps1C ，它们与细菌碳水化合物的生物合成基因具有氨基酸同源性。将卡那霉素抗性盒（Kan r ）插入跨越 cps1AB 的750 bp缺失或仅插入 cps1B 的512 bp缺失，然后将构建体克隆到自杀载体中。然后通过同源重组将Kan r 基因转移到4074菌株的染色体中，分别产生4074Δ cps 1N菌株和4074Δ cps 1B菌株。 。 4074Δ cps 1N菌株未产生可检测到的CP，但4074Δ cps 1B菌株却产生了由亲本菌株4074产生的1型血清型CP的15％（通过酶联测定）免疫吸附测定和游离CP沉淀。将4074菌株的 cps1ABC 基因以及血清型5a菌株J45的 cps5ABC 和 cps5ABCDE 基因克隆到穿梭载体pLS88中，并电穿孔入4074Δ< em> cps 1N产生4074Δ cps 1N（pAB cps 101），4074Δ cps 1N（pJML cps < / em> 53）和4074Δ cps 1N（pAB cps 55）。菌株4074Δ cps 1N（pAB cps 101）产生了菌株4074产生的1型CP的33％。菌株4074Δ cps 1N（pJML） cps 53）和4074Δ cps 1N（pAB cps 55）产生的血清型5a CP分别与产生的血清型相似或四倍在猪中进行相似剂量的气管内攻击后，产生1型血清型CP的菌株的毒力顺序如下（由死亡率，肺结实，出血和纤维化胸膜炎评估）：菌株4074>菌株4074Δ cps 1N（pAB cps 101）≥菌株4074Δ cps 1N>菌株4074Δ cps 1B。菌株4074Δ cps 1N（pJML cps 53）的毒性低于菌株4074Δ cps 1N（pAB cps 55） 。然而，两种菌株产生的血清型5a CP的数量与亲代菌株4074产生的血清型1 CP相似或更大，但毒性低于亲代菌株。因此，由 A的同基因菌株产生的血清型1或5a CP的量。胸膜肺炎与猪中细菌的毒性有关。但是，毒力还受到产生的CP类型或其表达机制的影响。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号