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Arsenic used as fundamental building block
The deadly poison, arsenic,
is used as a building block
for biological molecules such as
those in DNA. Scientists say that
the discovery that arsenic is used
by bacterium as a substitute for
phosphorous as it shares similar
properties.
Arsenic has been added to the
list of six elements involved in
the chemistry of life. The others
are oxygen, carbon, hydrogen, nitrogen,
phosphorous and sulphur.
It had been assumed by scientists
that for life to exist it had to contain
these same six elements as
the fundamental building blocks
of biological molecules.
An arsenic-using microbe
known only by its code name
GFAJ-1 was extracted from
muddy sediment in California’s
Mono Lake, which is naturally
salty and has high concentrations
of arsenic in its waters.
Tests have demonstrated that
the bacterium actually grows
better when it is exposed to
phosphorous but it appears to be
quite ready to use high concentrations
of arsenic in the absence
of phosphorous.
The study reports that arsenic
in the form of arsenate can make
the appropriate chemical bonds
with carbon and oxygen to act
as a substitute for the phosphate
molecule normally found in DNA
and other biological molecules.
Sophisticated analytical techniques
have shown that the arsenic
was incorporated into the
proteins, lipids, nucleic acids and
other vital molecules found inside
living cells.
The discovery has vindicated a
theory put forward by Dr Felisa
Wolf-Simon of the Nasa Astrobiology
Institute in 2006, which
suggested that primitive life
forms on Earth may have used
arsenic as building block. She
suggests that similar microbes
may still exist in some extreme
environments on Earth.
She says that the findings
show that the requirements for
life could be much more flexible
than had been assumed in the
past.
W
Watt’s Science
Anti-hydrogen atom found at CERN
European scientists have been able to
capture anti-hydrogen atoms in a novel
magnetic trap and they might now be on
track to unlock the mysteries of anti-matter
that have puzzled scientists for a long time.
Anti-matter is a subject of intense speculation
in the global scientific community because
it has been cited as a potential source
of boundless and almost cost-free energy.
CERN, the European Organisation for
Nuclear Research made the announcement
just a few weeks after another group working
on the same problem said that they had
made and caught elusive anti-matter atoms
for the first time.
Yasunori Yamazaki, a member of the
team that trapped the anti-hydrogen atom
says that anti-matter will not be able to hide
from researchers for much longer.
It is believed that anti-matter was created
in the same quantities as conventional
matter when the Big Bang occurred about
13,7-billion years ago.
In a separate announcement, CERN has
announced that it will be closing down its
Large Hadron Collider for two months after
it has had an unbroken stint of eight months
of scientific research.
CERN’s director-general, Rolf Geuer, says
that the scientific discoveries have been rolling
in so fast that the LHC’s operation will
be stretched to at least 2012, a year longer
than originally planned.
Apparently it was in the LHC that 38
anti-hydrogen atoms were captured in flight
and held for a fleeting moment so that initial
observations of their properties could be
made.
New equipment developed by Asacusa,
Alpha and Atrap overcame the problems
that had prevented the close study of antiparticles.
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