耶尔森氏菌属45Mdal质粒与Ca^（2＋）依赖性

The 45 Mdal Plasmid of Yersiniae and Ca2+ -Dependence

本文检查了鼠疫菌、假结核菌和小肠结肠炎菌的质粒ＤＮＡ，并观察了它们的Ｃａ２＋依赖性（Ｌｃｒ）。结果表明Ｌｃｒ与它们共有的４５Ｍｄａｌ质粒相关。但也存在有４５Ｍｄａｌ质粒而菌株为Ｌｃｒ－，或查不到４５Ｍｄａｌ质粒而菌株表现Ｌｃｒ＋。初步分析认为，前者可能是介导式操纵钙依赖性的基因失活，而后者可能是４５Ｍｄａｌ质粒整合在染色体上。

he plasmid DNA and Ca2+-dependence(Lcr )of Y.pestis,Y.pseudotuberculosis and Yenterocoliticawere examined in this study.Results indicated that the Lcr was correlated with their common 45 Mdal plas-mid. However,there were some strains which possessed 45 Mdal plasmid but Lcr or the plasmid couldn't bedetected but Lcr+. By preliminary analyse,we considered that the former be due to the inactivity mediating oroperating Ca dependent gene and the latter to the 45 Mdal plasmid intergrated on the chromosome.