de la Peña-Moctezuma A, Prescott J F
Department of Veterinary Microbiology and Immunology, University of Guelph, Ont., Canada.
Vet Microbiol. 1995 Oct;46(4):383-92. doi: 10.1016/0378-1135(95)00034-8.
HeLa cell association was examined in eight Rhodococcus equi isolates containing 80-85 kb plasmids and their plasmid negative derivatives, and in two other plasmid negative R. equi strains. Seven of the eight plasmid positive strains possessed an 85 kb plasmid and produced the virulence-associated protein (VapA) detected by monoclonal antibody staining in immunoblots; one of the eight had an 80 kb plasmid but did not produce VapA. Curing of the plasmids by repetitive subcultures at 42 degrees C in broth was confirmed by colony and DNA dot blot hybridization with a 7.5 kb BamHI-HindIII plasmid fragment probe, by attempted isolation of plasmid DNA, and by demonstration of lack of VapA. Most strains associated well with HeLa cells and no relationship was found with plasmid status and possession of VapA. Association with HeLa cells was significantly greater for strains with a dry colony type than for those with a mucoid colony, a result which correlated with hydrophobicity of the colonies. HeLa cell association does not correlate with the presence of the virulence plasmid in R. equi.
在8株含有80 - 85 kb质粒的马红球菌分离株及其质粒阴性衍生物以及另外2株质粒阴性的马红球菌菌株中检测了HeLa细胞结合情况。8株质粒阳性菌株中有7株拥有85 kb质粒，并产生了通过免疫印迹法用单克隆抗体染色检测到的毒力相关蛋白（VapA）；8株中的1株有80 kb质粒，但不产生VapA。通过在肉汤中42℃重复传代培养使质粒消除，这通过用7.5 kb BamHI - HindIII质粒片段探针进行菌落和DNA斑点印迹杂交、尝试分离质粒DNA以及证明缺乏VapA得以证实。大多数菌株与HeLa细胞结合良好，未发现与质粒状态和VapA的存在有相关性。与黏液样菌落的菌株相比，具有干燥菌落类型的菌株与HeLa细胞的结合显著更强，这一结果与菌落的疏水性相关。马红球菌中HeLa细胞结合与毒力质粒的存在无关。
