Fig. 2. Purification of type III secretion complexes from M94. (A) Each sample of partially purified type III secretion complexes was separated by 15% SDS–PAGE and the gel was stained with CBB or immuno blotted with antibodies specific for MxiD, MxiG and MxiJ. (B) A partially purified sample of type III secretion complexes from M94 was fractionated by 40% CsCl gradient centrifugation. Each fraction was separated by 15% SDS–PAGE and visualized by silver staining (upper part) or immunoblotted with antibodies specific for MxiD and MxiG (lower part).