Nanobacteria revelations provoke new controversy
19:00 19 May 04
Some claim they are a new life form responsible for a wide-
range of diseases, including the calcification of the
arteries that afflicts us all as we age. Others say they are
simply too small to be living creatures.
Now a team of doctors has entered the fray surrounding the
existence or otherwise of nanobacteria. After four years'
work, the team, based at the Mayo Clinic in Rochester,
Minnesota, has come up with some of the best evidence yet
that they do exist.
Cautiously titled "Evidence of nanobacterial-like structures
in human calcified arteries and cardiac valves", the paper
by John Lieske and his team describes how they isolated
minuscule cell-like structures from diseased human arteries.
A question of size
These particles self-replicated in culture, and could be
identified with an antibody and a DNA stain. "The evidence
is suggestive," is all Lieske claims.
Critics are not convinced. "I just don't think this is
real," says Jack Maniloff of the University of Rochester in
New York. "It is the cold fusion of microbiology." John
Cisar of the National Institutes of Health is equally
sceptical. "There are always people who are trying to keep
this alive. It's like it is on life support."
Kidney stones
The first claims about nanobacteria came from geologists
studying tiny cell-like structures in rock slices. But in
1998 the debate took a different twist when Olavi Kajander
and Neva Ciftcioglu of the University of Kuopio in Finland
claimed to have found nanobacteria, surrounded by a calcium-
rich mineral called apatite, in human kidney stones.
Objections were raised immediately. Many of the supposed
nanobacteria were less than 100 nanometres across, smaller
than many viruses, which cannot replicate independently.
Maniloff's work suggests that to contain the DNA and
proteins needed to function, a cell must be at least 140
nanometres across.
Kajander and Ciftcioglu, however, insisted that they had
observed the nanoparticles self-replicating in a culture
medium and claimed to have identified a unique DNA sequence.
How could this be explained if the cells were not alive,
they asked.
Cisar has an answer to this. After studying nanoparticles
found in saliva, his team published a paper in 2000 claiming
that the DNA detected by the Finnish team was a contaminant
from a normal bacterium. "It wasn't until we couldn't get
any unique nucleic acids that we suddenly realised we were
being tricked," he says. The paper also said that what
looked liked self-replication was just an unusual process of
crystal growth.
"This just stopped everything in its tracks," says Virginia
Miller, a member of Lieske's team. "It is cited as the
gospel to why all the papers by Kajander are rubbish... The
debate is very polarised and that has shocked me a bit."
Some say the claims of Cisar's team are also fantastic.
"They talk about 'self-propagating apatite'," says Jorgen
Christoffersen, who studies biomineralisation at the
University of Copenhagen in Denmark. "This is scientific
nonsense."
Read the rest at New Scientist
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Posted by Robert Karl Stonjek.