Is nano bacteria a living organism?

Tiny molecules called nanobacteria have confounded scientists in many ways since people discovered it 20 years ago, but the most controversial question it poses is whether they whether to live or not.

CaCO3 crystals (molecules similar to nanobacteria) look like a cell but the new work shows that nanobacteria are not living organisms.(Photos: Martel and Young)

Nanobacteria - sometimes called 'nanobes' or ' calcified nanoparticles' - do not seem to meet scientists' standards for life. Researchers at a research laboratory maintained by the National Academy of Sciences concluded that the minimum cell size of life on Earth must have a diameter exceeding 200 nm to contain cell-based mechanisms for regeneration. ADN. But nanobacteria can be as small as 80 nm, so unless they bring a new regeneration mechanism, they don't seem to be a form of life.

It is only part of the evidence against the existence of nanobacteria given in a recent work by Jan Martel, Chang Gung University in Taiwan, and John Ding-E Young, Rockefeller University in New York, published in PNAS. Martel and Young have studied healthy human blood plasma containing 'nanobacteria-like molecules' (NLP), containing CaCO3 compounds, or limestone. Scientists have carried out a series of experiments showing that these tiny molecules do not contain signs of DNA and RNA, and that their formation can be explained by non-biological measures. learn.

Young told PhysOrg.com 'We believe that this work provides important evidence that nanobacteria are not living objects. Some previous studies have suggested this but have not yet included a chemical compound or formulation that can completely explain the phenomenon of nanobacteria. '

One thing that is clear about nanobacteria is that they are very popular, almost present in all human samples. Under electron microscopes, nanobacteria and even NLP look like normal bacteria, even more like dividing cells. They are also quite certain, according to previous works, when scientists screened NLPs with 30 kGy (kiloGray) gamma radiation, they still grow in culture media.

Another bacterium-like property of NLP is that they are able to form the nucleus of hydroxyapatite (HAP), a calcium phosphate crystal that is a major component of human or animal bones and teeth. Previous works suggest that this is a way to copy nanobacteria itself. However, when Martel and Young surveyed this issue in their work, they found that HAP only formed around NLP under certain conditions. For example, when mixed with crystal-forming proteins, NLP stops making HAP nuclei, meaning that HAP is not really necessary for NLP formation.

Instead, their experiments led Martel and Young to conclude a chemical model rather than biology for NLP formation. Based on this assumption, they were able to control the speed and shape of NLP formation in vitro by simply changing the substrate needed for calcium carbonate deposition.

These findings may also reveal more information about nanobacteria that appear elsewhere, from the sandstone of Tria and Jura to meteorite fragments from Mars. The chemical process that scientists describe nanobacteria formation may be similar for these nanobacteria.

'Nanobacteria are predicted to be the smallest form of cells on Earth and are candidates for explaining the origin of cell life on Earth and other places in the universe like meteorites and Mars. Our results clearly disprove the possibility that nanobacteria are living organisms. ' Previous research has suggested that nanobacteria can cause quite a number of diseases, from kidney stones to atherosclerosis - an ability that can now be verified with new nanoparticles. Because they multiply faster in low-gravity environments, NASA is particularly concerned about the astronauts' risk of developing kidney stones. According to Martel and Young, these nanoparticles could belong to a wider family of organic mineral complexes that seem to be able to gather and multiply as if they were living - in fact, very similar to prions, a self-focused protein that causes mad cow disease.

'We believe we have just discovered a family of organic mineral complexes that seem to be able to replicate and concentrate on themselves like living organisms. They appear to be everywhere, in both living and non-living matter. '

Some researchers are even developing antibodies to defeat 'pathogenic' nanobacteria . A company called Nanobac Oy, owned by Nanobac Life Sciences and founded by nano-bacteriologists, has antibodies that commercialize and sell nanobacteria diagnostic kits. These antibodies are derived from nano-immunized mouse cells from cows.

To try to understand the nature of the reaction of antibodies and nanobacteria, Martel and Young tried antibodies on NLPs, and produced positive results as expected. However, surprisingly, these antibodies also react with albumin, the most common protein in serum. The researchers explained that because proteins like albumin cannot be produced by any living bacteria, they probably stick to CaCO3 molecules, and react with antibodies.

Young added, ' Because nanobacteria have been proven not to be living organisms, they cannot produce disease like bacteria. Their appearance in both living and non-living environments - from blood samples to meteorites - must be focused in identifying their role in diseases. It is not that such nanoparticles cannot cause disease - they may be related - but any similar statement must be seriously established through certified documents, which are lacking in the present. '