%0 Journal Article %A Bertoloni, Giulio %A Viel, Alessandra %A Grossato, Anna %A Jori, Giulio %T The Photosensitizing Activity of Haematoporphyrin on Mollicutes %D 1985 %J Microbiology, %V 131 %N 9 %P 2217-2223 %@ 1465-2080 %R https://doi.org/10.1099/00221287-131-9-2217 %I Microbiology Society, %X Summary: The photosensitizing activity of haematoporphyrin (HP) on Mycoplasma hominisand 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 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 andlysed 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. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-131-9-2217