Morphology of three strains of contagious equine metritis organism

Abstract

Examination of recently isolated cultures of three strains of Contagious Equine Metritis Organism grown on specially formulated, serum-free, clear typing medium revealed the presence of numerous colonial opacity variants. These colonies were prepared by a number of fixation and staining techniques and examined by scanning and transmission electron microscopy. Opaque and transparent phenotypes produced copious amounts of extracellular material compared with intermediate-opacity phenotypes which produced little or none. Also unique to intermediate colonies were numerous thin intercellular strands, which may represent pili or polymers of extracellular material. The presence of an unusual fibrillar layer (with similar electron density to the extracellular material) on the outer leaf of the outer membrane also was confirmed. A number of other ultrastructural features also were noted, including an epilayer, a thin nonmembranous layer which covered colonies and adjacent agar.

Clinical, bacteriologic, serologic, and pathologic features of infections with atypical Taylorella equigenitalis in mares

“…Taylorella equigenitalis isolates do vary in pathogenicity and are somewhat pleomorphic in colonial morphology following animal passage. [8][9][10][11] In our study, recovered atypical KY isolates were, however, of a uniformly small colony phenotype. In the 1980s, smallcolony variants of classic T equigenitalis were observed and were pathogenic, but they could be recovered in either large or small colony form after animal passage.…”

Isolation of the equine granulocytic ehrlichiosis agent, Ehrlichia equi, in tick cell culture

“…Electron microscopy. Cultures were processed for electron microscopy as described elsewhere (19,23). Briefly, 0.25-ml volumes of cells from an infected culture, 3 and 4 months after initiation of the primary culture and passaged twice and three times, respectively, in IDE8 cells, were centrifuged for 10 min at 150 ϫ g, and the pellet was flooded twice with ice-cold modified Ito's (20) fixative (43).…”

“…Resin was replaced after each of two 1-h incubations and again after 4 and 16 h and then polymerized. Thin sections were cut with a diamond knife by using a Reichert Om U3 microtome, stained with lead citrate (36,41) or uranyl acetate and 1% KMnO 4 (19), and viewed and photographed with a Hitachi HU-11E-1 electron microscope by using Kodak SO 163 film.…”

Pilus- gonococcal variants. Evidence for multiple forms of piliation control.

“…The specimens were placed in the critical point drying apparatus in absolute ethanol or acetone for 2-16 h, after which they were subjected to critical point drying and applied to SEM stubs with conductive silver paint. Gold-palladium coating was performed in a Hummer X sputter coater, and the specimens were viewed with a scanning microscope (JSM-35CF; JEOL USA, Peabody, MA), as described elsewhere in detail (20).…”