Nanobe.html



A nanobe

Nanobes are tiny filamental structures first found in some rocks and sediments. Some hypothesize that they are the smallest form of life, 1/10th the size of the smallest known bacteria. No conclusive evidence exists for whether these structures are, or are not, living organisms, and their classification is controversial.¹

Nanobes were discovered in 1996 (published in American Mineralogist, vol 83., 1998) by Philipa Uwins², University of Queensland, Australia.³ They were found growing from rock samples (both full-diameter and sidewall cores) of Jurassic and Triassic sandstones, originally retrieved from an unspecified number of oil exploration wells off Australia's west coast. Depths of retrieval were between 3,400 metres (2.1 mi) and 5,100 metres (3.2 mi) below the sea bed. While Uwins et al present assertions against it, they do not exclude the possibility that the nanobes are from a surface contaminant, not from the rock units cited.

It was once thought that cellular life could not exist below 200 nanometers in size. But this is based, in part, on the inability to see any object smaller than 200 nanometers with an optical microscope, rendering normal observation of life below that size impossible[1].

The smallest are just 20 nanometers in diameter. Some researchers believe that these structures are crystal growths, but the staining of these structures with dyes that bind to DNA might indicate that they are living organisms.⁴ They are similar to the structures found in ALH84001, a Mars meteorite found in the Antarctic. Recently there has been some interest amongst bio-tech companies in commercial application of nanobes in utilization of plastics.^{citation needed}

Nanobes are similar in size to nanobacteria, which are also structures that have been proposed to be extremely small living organisms. However, these two should not be confused. Nanobacteria are supposed to be walled organisms, while nanobes are hypothesized to be a previously unknown form of life.

Claims

• It is a living organism (contains DNA or some analogue, and reproduces).
• Has a morphology similar to Actinomycetes and Fungi.
• Nanobes are 20 nm in length which conventional biological knowledge assumes is too small to contain the basic elements for an organism to exist (DNA, plasmids, etc.), suggesting that if they reproduce they would need to do so in an unconventional way, such as using RNA instead of DNA.
• The Martian meteorite ALH84001, discovered in 1984 in the Antarctic, contained similar^{citation needed} tubular structures which some astrobiologists suggested could be evidence of life at an earlier time on Mars.

References

See also

• Mycoplasma genitalium, Pelagibacter ubique — some of the smallest known bacteria
• Nanoarchaeum — smallest known archaeum
• Mimivirus — largest known virus
• Parvovirus — smallest known family of viruses
• Nanobacterium

External links

• Color photo of a nanobe colony
• Definition of nanobe
• Introduction to nanobes
• "Nanobes: A New Form of Life?"
• Nanobe images and links
• Transcript of interview of Phillipa Uwins
• Size Limits of Very Small Microorganisms Proceedings of a Workshop organized by the National Academies of Sciences