Nanobacteria: What Does their Existence Imply?

TruthSeeker

TruthSeeker

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http://news.bbc.co.uk/1/hi/sci/tech/300949.stm

If they exist, what does that mean? Does it mean that they were the first forms of life? Or does it mean that they are evolved from eukariotyc or prokaryotic cells? Because as they have a smaller size, they can have a faster metabolism, evolve faster, multiply faster and function in a much faster way. So it would be much more logical to think of them as an evolved form of life!

So if nanobacteria exist, maybe they are more evolved than... well, us- in a way. Maybe someday we will have pluricellular life-forms evolving from those tiny bacteria.

Or maybe they are just the primordials of mitochondria and chloroplasts? But that would depend on size. Does anyone know how they would compare in size (mitochondria/clhoroplast and nanobacteria)?


Looks like that is a big question of evolution...... :eek:​
 
As far as I understand it, you can't say something is more evolved than something else, because that implies a fixed evolution and evaluation point, whereas what you get in evolution is adaptation to change, in a manner that rules out saying something is more evolved.
That said, it looks interesting, but we'll have to see what else they come up with.
 
Oh yeah, certainly. But what I really asked was in relation to the chronological evolution- that is, were nanobacteria the first living beings or they are brand new "creations"?
 
Nanobes are a tenth the size of the smallest know bacterium, so they'd be much smaller that mitochondria or chloroplasts. The mainstream thinking is that original life was smaller and simpler, so the nanobes should be primordial rather than modern.
 
Well actually nanobacteria or nanobes have been described since the 90s, isolated from animal tissues and soil. Most belong to the alpha proteobacteria. They are typically 0.2-0.5 µM in size, though smaller forms have been found withTEM and are putatively involved in kidney stone formation.
See for instance:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=9653177

However other findings suggest that the identifcation was based on contamination by other 16sRNA: http://www.pnas.org/cgi/content/full/97/21/11511

Although the controversy is afaik not resolved yet (mostly due to technical problems in characterizing them biochemically), there are quite a few publications that base on the presence of nanobacteria.
Now assuming that they exist, it is still not easily possible to infer an evolutionary relationship between this and other bacteria simply by size (especially not if the mechanisms which allow them to propagate sucessfully dispite the small size). For instance many pathogens tend to have smaller genome and also cell sizes as quite often they do not need to have the metabolic activities as for instance free-living bacteria. While associated with the host they got a fairly stable environment and may live off from its host ressources. Of course, in turn they have to possess mechanisms to avoid the host immune response, but overall usually less genes are needed than to prevail in constant changing enviroments with limited ressources.
As such it is therefore possible that the small size of nanobacteria is an adaptation to a parasitic life e.g. in human hosts.
 
It could just as well be an adaptation to a parasitic life in bacterial hosts.
 
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