Fig. 4. Immunogold EM with the AB1 monoclonal antibody. Cytoskeletons fixed with methanol (A,B) and unfixed cytoskeletons (C) both show 10-nm gold staining of the flagella connector (*), which is defined by the presence of electron-dense material between the tip of the new flagellum (nf) and the side of the old flagellum (of). Scale bars, 200 nm