title: Protoplast and cytoplasmic membrane preparations from Streptococcus sanguis and Streptococcus mutans.
abstract: Protoplasts were prepared from Streptococcus sanguis and some S. mutans serotypes by use of lysozyme (EC 3.2.1.17) under particular conditions: cells had to be grown in DL-threonine (20 mM) and harvested in early exponential phase. The efficiency of protoplast formation was enhanced by two additional steps: plasmolysis (in 12% PEG), prior to addition of lysozyme, and a swirling phase, after the enzymic action. This procedure allowed us to obtain clean protoplasts, with only 0.5% contamination by bacterial cell walls. Up to 90% protoplast lysis was obtained in 0.5 M-NaCl. Cytoplasmic membrane purification was achieved by centrifugation on a glycerol cushion.
mesh_terms: D001431:Bacteriological Techniques; D001433:Bacteriolysis; D002462:Cell Membrane / Q000648:ultrastructure; D008854:Microscopy, Electron; D009113:Muramidase; D011523:Protoplasts / Q000648:ultrastructure*; D013295:Streptococcus mutans / Q000648:ultrastructure*; D013298:Streptococcus sanguis / Q000648:ultrastructure*
chemical_list: D009113:Muramidase