No abstract

Treponema cuniculi was studied in the electron microscope by means of negative staining and ultrathin sectioning techniques. The sectioned organisms were studied in situ in biopsies from lesions of infected skin. Cells of T. cuniculi were found to be regular helices 8–15 μm long and 0.15 μm wide. The ends of the cells were pointed and three flagella were inserted in a row subterminally at each end. The flagella wound around the organisms and overlapped in the middle of the treponemes. The fine structure of isolated flagella was similar to that of flagella obtained from other treponemes. Treatment of T. cuniculi with Myxobacter AL‐1 protease 1 revealed bundles of intracytoplasmic microtubules. The diameter of each tubule was about 7 nm. In the ultrathin sections of infected tissue T. cuniculi was observed in intercellular spaces in the stratum spinosum and the stratum basale layers of the epidermis. No treponemes were observed in the connective tissue of the dermis. Sections of the microorganisms show the same structural pattern as previously described for T. pallidum Nichols. The organisms are surrounded by two tripple‐layered membranes with the flagella situated in between. The ultrastructure of the pathogenic treponemes, T. cuniculi, T. pallidum and T. pertenue is compared.

Leptospira strain Pomona was studied by negative staining and ultrathin sectioning techniques. The effect of various fixatives on the preservation of cellular details was evaluated. The helical cytoplasmic cell bodies were surrounded by a triple‐layered cytoplasmic membrane with an intermediate layer in close apposition to the outer aspect of the membrane. The outer envelope of the cell consisted of an ordinary triple‐layered membrane with an additional layer exterior to it. This exterior layer may roll off or break off from damaged leptospira cells, and may then be found as finely striated tubules in negatively stained preparations. Usually cells had two axial filaments, one inserted subterminally at either end of the cell. The filaments were entwined around the cytoplasmic body and were situated between the cell body and the outer envelope. An overlap of the axial filaments on the body of the cell was not observed. Dividing cells had four axial filaments, one inserted at either end of the two daughter cells. The dimensions and the substructure of liberated axial filaments were studied and compared with those on flagella of treponemes and bacteria.

Cells of Treponema genitalis were studied in the electron microscope by means of negative staining and ultrathin sectioning techniques. All cells were covered by a regularly structured surface layer. This layer appeared to consist of pairs of thin fibrils attached to an amorphous layer. This amorphous layer in turn is probably identical with the exterior part of the outer membrane of the organism. The pairs of thin fibrils located on this surface were interconnected by polygons. The treponemes were regularly coiled and had somewhat tapered ends with 2–4 flagella inserted at each end. The two bundles of flagella were entwined around the cytoplasmic body of the cell and interdigitated in the middle region of the organism. Treatment of cells of T. genitalis with Myxobacter AL‐1 protease 1, or with deoxycholate did not reveal intracytoplasmic tubules. This is in contrast to the results obtained with similar treatments of all other strains of species of Treponema hitherto examined.

TreponernaReiter was studied by negative staining and ultrathin sectioning techniques after treatment with the (detergents, Teepol and sodium deoxycholate, and with the proteolytic enzyme AL-1. Special attention was paid to the insertion ends of the endoflagella, and the structures revealed have been compared with those published by other workers on the attachment lends of bacterial flagella of various species. All the treatments freed the flagella from the treponeme though the basal discs were often obscured by membrane fragments adhering to them. The endoflagella were found to consist of the following structural parts: 1) a sheathed shaft, 2) a hook that differs from the shaft both in width and in substructure, 3 ) a narrow, smooth collar that connects the hook to the basal disc, and Received 15.vii.70 Requests for reprints should be addressed to: