[Isolation and characterization of mitogens from Nocardia].

Two methods have been devised to isolate mitogens from Nocardia cells. (1) Lysozyme treatment of delipidated cells followed by fractionation of the soluble extract leads to a mitogen devoid of cell wall constituents. (2) Cell disruption followed by differential centrifugations shows that two mitogenic structures are present: the cell wall and fragments of the cytoplasmic membrane. The active component of the cell wall is the peptidoglycan wherefrom soluble mitogenic fractions have been obtained using bacteriolytic enzymes other than lysozyme. An intact glycan moiety seems necessary for mitogenic activity.