RT Journal Article SR Electronic(1) A1 Bertoloni, Giulio A1 Viel, Alessandra A1 Grossato, Anna A1 Jori, GiulioYR 1985 T1 The Photosensitizing Activity of Haematoporphyrin on Mollicutes JF Microbiology, VO 131 IS 9 SP 2217 OP 2223 DO https://doi.org/10.1099/00221287-131-9-2217 PB Microbiology Society, SN 1465-2080, AB 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., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-131-9-2217