...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Infection and immunity >Isolate and epitope variability in susceptibility of Giardia lamblia to intestinal proteases.
【24h】

Isolate and epitope variability in susceptibility of Giardia lamblia to intestinal proteases.

机译：贾第鞭毛虫对肠道蛋白酶敏感性的分离和表位变异性。

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

摘要

The surface antigens of Giardia lamblia differ. To determine whether the unique surface antigens found in variants and isolates could differentially protect the parasite from digestion by intestinal protease, G. lamblia clones WB-2X (WB), GS/M-H7 (GS/M), and B6, each of which expresses a unique surface variant antigen, were exposed to alpha-chymotrypsin and trypsin at concentrations up to 20 mg/ml in culture medium. The number of surviving trophozoites and morphologic changes were assessed over time. After 24 h, there was a significant decrease in the number of surviving trophozoites of WB (80.5 and 94.2% for trypsin and alpha-chymotrypsin treatments, respectively, compared with controls) and B6 (78.9 and 95.5% for trypsin and alpha-chymotrypsin treatments, respectively, compared with controls) at 10 mg of enzyme per ml compared with culture medium alone. Cytotoxicity was prevented by the presence of soybean trypsin inhibitor, indicating the effects were due to protease activity. In contrast, there was no significant cytotoxicity after exposure of GS/M to either enzyme at the same enzyme concentration. After exposure to alpha-chymotrypsin, susceptible G. lamblia became rounded and then lysed, but after exposure to trypsin, G. lamblia appeared plastered onto the surface of the well and was intertwined and surrounded by finely granular material. Effects were concentration and time dependent; at least 6 h of treatment was required to observe changes 12 to 18 h later. Trophozoites surviving alpha-chymotrypsin or trypsin exposure became stably resistant to protease treatment. In vitro, the variant surface antigen of GS/M, but not those of WB or B6, resisted digestion by trypsin or alpha-chymotrypsin, suggesting that the variant surface antigens impart susceptibility or resistance to digestion. The initial surface variant antigens of WB and B6 were replaced in resistant cultures. Trophozoites differ in their ability to survive after exposure to intestinal proteases, which may enable certain G. lamblia isolates or isolates possessing certain surface variant antigens to survive in the small intestine.
机译：贾第鞭毛虫的表面抗原不同。为了确定在变体和分离物中发现的独特表面抗原是否可以差异保护肠道寄生虫免受肠道蛋白酶的消化，G。lamblia克隆WB-2X（WB），GS / M-H7（GS / M）和B6各自将表达独特表面变体抗原的抗原暴露于培养基中浓度高达20 mg / ml的α-胰凝乳蛋白酶和胰蛋白酶。随时间评估存活的滋养体数量和形态变化。 24小时后，WB的存活滋养体数量显着减少（与对照相比，胰蛋白酶和α-胰凝乳蛋白酶治疗分别为80.5和94.2％）和B6（胰蛋白酶和α-胰凝乳蛋白酶治疗分别为78.9和95.5％）与单独的培养基相比，每毫升含10 mg的酶）。大豆胰蛋白酶抑制剂的存在可防止细胞毒性，表明其作用是由于蛋白酶活性引起的。相反，在相同的酶浓度下，GS / M暴露于任何一种酶后，都没有明显的细胞毒性。暴露于α-胰凝乳蛋白酶后，易感的G. lamblia变圆，然后裂解，但是暴露于胰蛋白酶后，G。lamblia似乎被粘贴在孔的表面，并缠绕在一起并被细颗粒物质包围。影响取决于浓度和时间。需要至少6小时的治疗才能在12至18小时后观察到变化。存活于α-胰凝乳蛋白酶或胰蛋白酶的滋养体对蛋白酶处理稳定地产生抗性。在体外，GS / M的变体表面抗原，而不是WB或B6的变体表面抗原，可抵抗胰蛋白酶或α-胰凝乳蛋白酶的消化，表明该变体表面抗原赋予了消化敏感性或抗消化性。 WB和B6的初始表面变异抗原在抗性培养物中被替换。滋养体暴露于肠蛋白酶后其存活能力不同，这可能使某些兰氏菌分离株或具有某些表面变异抗原的分离株能够在小肠中存活。

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