Niang M, Rosenbusch R F, Andrews J J, Kaeberle M L
Department of Microbiology, Immunology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames 50011, USA.
Am J Vet Res. 1998 May;59(5):557-62.
To examine Mycoplasma ovipneumoniae for presence of a capsule and its potential role in adherence.
17 isolates of M ovipneumoniae and 2 isolates of M arginini, recovered from sheep with respiratory tract disease.
Mycoplasmas were cultured in modified Fills broth medium, ovine fetal lung cells, or ovine tracheal ring explants. Pelleted mycoplasmas or ring cultures infected with mycoplasmas were treated with ruthenium red or polycationic ferritin and visualized by transmission electron microscopy. Reactivity of several lectins with the mycoplasmas was studied by use of a microtitration plate agglutination test.
Electron microscopy revealed a large number of M ovipneumoniae cells covered with an electron dense-stained amorphous material suggesting that it was a capsule. Multiple passages of the microorganisms in modified Friis broth medium decreased thickness of the capsule, but not percentage of cells encapsulated. Marked differences were observed when M ovipeumoniae isolates grown in modified Friis broth medium or co-cultured with ovine fetal lung cells were compared for capsular thickness or percentage of encapsulation. In thin sections of ruthenium red-stained tracheal ring cultures, the mycoplasmas appeared to be in close contact with cilia through their capsule. All isolates of M ovipneumoniae reacted strongly with wheat germ agglutinin lectin.
Mycoplasma ovipneumoniae produces a polysaccharide capsule with variable thickness that is dependent on culture conditions and strain. Morphologic observations suggest that this capsule facilitates adherence of the organism to ciliated epithelium.
检测绵羊肺炎支原体是否存在荚膜及其在黏附中的潜在作用。
从患有呼吸道疾病的绵羊中分离出17株绵羊肺炎支原体和2株精氨酸支原体。
支原体在改良的弗里斯肉汤培养基、绵羊胎肺细胞或绵羊气管环外植体中培养。用钌红或聚阳离子铁蛋白处理沉淀的支原体或感染支原体的环培养物，并通过透射电子显微镜观察。通过微量滴定板凝集试验研究几种凝集素与支原体的反应性。
电子显微镜显示大量绵羊肺炎支原体细胞被电子密度染色的无定形物质覆盖，表明这是一种荚膜。微生物在改良的弗里斯肉汤培养基中多次传代后，荚膜厚度降低，但被包囊的细胞百分比未降低。比较在改良的弗里斯肉汤培养基中生长或与绵羊胎肺细胞共培养的绵羊肺炎支原体分离株的荚膜厚度或包囊百分比时，观察到明显差异。在钌红染色的气管环培养物的薄片中，支原体似乎通过其荚膜与纤毛紧密接触。所有绵羊肺炎支原体分离株与麦胚凝集素反应强烈。
绵羊肺炎支原体产生一种厚度可变的多糖荚膜，其厚度取决于培养条件和菌株。形态学观察表明，这种荚膜有助于该生物体黏附于纤毛上皮。
