Nanobacterium

nanobacteria /ˌnænoʊbækˈtɪəriə/ NAN-oh-bak-TEER-ee-ə) is the unit or member name of a former proposed class of living organisms, specifically cell-walled microorganisms, now discredited, with a size much smaller than the generally accepted lower limit for life (about 200 nm for bacteria, like mycoplasma).

Originally based on observed nano-scale structures in geological formations (including the Martian meteorite Allan Hills 84001), the status of nanobacteria was controversial, with some researchers suggesting they are a new class of living organism[2][3] capable of incorporating radiolabeled uridine,[4] and others attributing to them a simpler, abiotic nature.

Early in 1989, geologist Robert L. Folk found what he later identified as nannobacteria (written with double "n"), that is, nanoparticles isolated from geological specimens[11] in travertine from hot springs of Viterbo, Italy.

Initially searching for a bacterial cause for travertine deposition, scanning electron microscope examination of the mineral where no bacteria were detectable revealed extremely small objects which appeared to be biological.

[12] In 1996, NASA scientist David McKay published a study suggesting the existence of nanofossils — fossils of Martian nanobacteria — in ALH84001, a meteorite originating from Mars and found in Antarctica.

[5] In 2004, a Mayo Clinic team led by Franklin Cockerill, John Lieske, and Virginia M. Miller reported to have isolated nanobacteria from diseased human arteries and kidney stones.

Further work on the importance of nanobacteria in geology by R. L. Folk and colleagues includes study of calcium carbonate Bahama ooids,[20] silicate clay minerals,[21] metal sulfides,[22] and iron oxides.