Nanobacterium

Nanobacterium (/ˌnænoʊbækˈtɪəriəm/ NAN-oh-bak-TEER-ee-əm, pl. 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.^[5][6] One skeptic dubbed them "the cold fusion of microbiology", in reference to a notorious episode of supposed erroneous science.^[7] The term "calcifying nanoparticles" (CNPs) has also been used as a conservative name regarding their possible status as a life form.

Research tends to agree that these structures exist, and appear to replicate in some way.^[8] However, the idea that they are living entities has now largely been discarded, and the particles are instead thought to be nonliving crystallizations of minerals and organic molecules.^[9]