Axial fibrils in the periplasmic region of a cell control the spirochete's screw-like movement through the septum cross.
Gram-negative, mobile, spiral bacteria with a length of 3 to 500 m (1 m = 0.001 mm) are known as spirochetes. Depending on the species, spirochetes can have 2 to more than 100 endocellular flagella (axial fibrils, or axial filaments) per organism. Spirochetes, such as the Borrelia, Treponema, and Leptospira species, have specialized flagella that are found in the periplasm. Spirochetes are a collection of six species of spiral-shaped, thin bacteria of varied length that swim ahead in a corkscrew-like motion thanks to the spinning of the periplasmic flagella. They either live freely or are attached to a host.
