Biochemical and ultrastructural changes in Staphylococcus aureus treated with staphylococcin 1580

Incorporation of precursors into macromolecules is immediately arrested upon treatment of Staphylococcus aureus cells with staphylococcin 1580. Except for a degradation of RNA, induced after about 40 min, no degradation of macromolecules is observed, and no trichloroacetic acid-insoluble components are released from the cells.The protein composition and content of membranes are not affected by staphylococcin 1580 treatment. The fatty acid pattern of cells is not significantly altered.Protoplasts do not lyse apparently upon treatment with staphylococcin 1580, but undergo morphological alterations.Thin sections of cells treated with the bacteriocin for 30 min show extensive mesosome-like structures, mostly arranged in honeycomb arrays connected to the plasma membrane, and alterations in the nucleoid area. Freeze-etched preparations taken after that time reveal alterations in the plasma membrane, presumably in relation to the formation of the mesosomal structures. No alterations were observed after bacteriocin treatment for 5 min, although at that time the permeability of the membrane is strongly affected.The implications of the observed changes with the development of irreversible lesions in the cells are discussed.