Spiroplasma is a genus of
Mollicutes, a group of small
bacteria without
cell walls.
Spiroplasma shares the simple
metabolism, parasitic lifestyle, fried-egg colony morphology and small genome of other
Mollicutes, but has a distinctive helical morphology, unlike
Mycoplasma. It has a spiral shape and moves in a corkscrew motion. Most spiroplasmas are found either in the gut or
haemolymph of insects, or in the
phloem of plants. Spiroplasmas are
fastidious organisms, which require a rich culture medium. There has been no success in culturing insect symbionts
in vitro. Typically they grow well at 30 °C, but not at 37 °C. A few species, notably
Spiroplasma mirum, grow well at 37 °C (human body temperature), and cause
cataracts and neurological damage in suckling mice. The best studied species of spiroplasmas are
Spiroplasma citri, the causative agent of
Citrus Stubborn Disease, and
Spiroplasma kunkelii, the causative agent of
Corn Stunt Disease.