Spirochetes
Spirochetes are spiral-shaped, free-living, anaerobic bacteria. They are prokaryotes on the prowl. Having no need of oxygen indicates an ancient lineage.
Spirochetes are found in a wide variety of habitats, from swimming in mud to the guts of desert termites.
As a disease organism, a spirochetal bacterium, Treponema pallidum, causes syphilis in humans.
Spirochetes swim via a curious corkscrew motion, like the swiggles of sperm cells heading to an egg.
Some free-living spirochetes attach themselves to larger cells, providing propulsion. A taxi-driving spirochete gets its fare from leftovers of its cellular passenger.
Spirochete cilia are a ring of microtubules, like spun wires in an electrical cable. Some spirochete sport fine filaments spun from the same protein from which eukaryotes form microtubules. A characteristic animal pattern is 9 double tubules in a ring, with another double tubule holding down the middle, in a hub-and-spoke configuration.
