ELECTRON MICROSCOPY OF BORRELIA MERIONESI AND BORRELIA RECURRENTIS

Borrelia merionesi and Borrelia recurrentis were studied in the electron microscope by means of negative staining and sectioning techniques. The cells of the two species had similar morphology. The cells were regularly waved and had pointed ends. Each organism had two bundles of flagella, one bundle originating from each end of the cell and each bundle consisting of 15–20 flagella. The flagella were twined together with the cytoplasmic body and overlapped in the middle region of the cell. The dimensions and the structures of flagella isolated from Borrelia were similar to the corresponding structures of flagella isolated from treponemes and gram-positive bacteria. A model for the sequence of morphological changes observed during the division process of Borrelia is proposed.