Heating Effects on the Leptospira Cells

The cultural cell suspensions of leptospira (L. canicola) were heated at various grades of temperature and the effects on the cells were investigated under darkfield illumination microscopy (DFIIM) and transmission electron microscopy (TEM). Moreover, the reproductive ability of the heated cells was examined by cultivation in the fresh media. The results obtained were summarized as follows : Motility of leptospira cells disappeared by the following conditions of heating, such as at 51℃ for 15 min and at65℃, for 5 min. The reproductivility of leptospira cells was not recognized by the following conditions of heating, such as at 56℃for 10 min and at 65℃ for 5 min. Morphological effects of heating to the leptospira cells were recognized to be remarkable by both DFILM and TEM. The most striking deformation of cell body was spherical body (SB) formation by the heating at 100℃ for 10 min. It was considered that SB formation might be brought by the fusion of capsule after heating. Cell bodies also demonstrated various morphologic damages, such as reduction and split of cell body, relaxation of helix, granulization or condensation of cytoplasma. Capsule showed swelling, detachment, fusion and vesicle formation after heating of higher grades of temperature. Axial flagella disappeared by the heating at 65℃ for 15 min. This fact is regarded as the result of dissolution of flagellin by heating, and also as the possession of the same composition in the flagella of general bacteria.