The photosensitizing activity of haematoporphyrin (HP) on Mycoplasma hominis and Acholeplasma laidlawii was studied as a function of the phase of growth and the amount of sterols in the cell membrane. Less HP was bound to cells when the membrane had a high sterol content. Both strains in the exponential but not in the stationary phase of growth were sensitive to HP treatment (above 1 μg ml-1) in the dark. Visible light irradiation of HP-loaded cells caused in all cases a decrease of cell survival, with concomitant changes in the pattern of membrane proteins that suggested protein-protein cross-linking, and the appearance of ultrastructural alterations (rounded and lysed cells); the photosensitivity was indirectly related to the sterol content of the cell membrane. On the whole, our findings suggest that the cell membrane is a major target for HP photosensitization of mycoplasma cells.
|Number of pages||7|
|Journal||Journal of General Microbiology|
|Publication status||Published - 1985|
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