Tightly Coiled Spirochete 0.25um OS outer sheath AF axial fibrils oS Leptospira interrogans AF Protoplasmic cylinder Periplasm Outer membrane Flagella Figure 18 44a Microbiology: An Evolving Science5 Tightly Coiled Spirochete AF OS = outer sheath AF = axial fibrils Leptospira interrogans