From Mark Crispin Miller
ISIS Report 14/01/05
Mobile Phone Turns Enzyme Solution into A Gel
A
highly reproducible non-thermal effect of mobile
phones depends on interaction between protein and
water. Dr. Mae-Wan Ho says it brings
us closing to understanding the biophysics involved
in how weak electromagnetic radiation can have
biological effects.
Sources for this
article are posted on ISIS members’ website. Details here
Serious brain damage unaccounted for
The
most striking effect of exposure to the
radio-frequency (RF) radiation from mobile phones is
damage to the brain and brain cells of rats (see
"Mobile phones & brain damage" SiS24),
which were found at levels of exposure far below the
current safety limits. After just two hours of such
exposure, blood albumin leaked into the brain causing
brain cells to die; and the effects lasted for at
least 50 days after a single exposure. But no clear
mechanism has emerged to explain this or other
‘non-thermal’ effects of electromagnetic fields (EMFs)
even after a concerted, Europe-wide research programme
(see "Confirmed:
mobile phones break DNA and scramble genomes",
this series).
I
have suggested that phase changes in cell water
triggered by EMFs may be involved in causing many
biological effects, but there has been a complete lack
of support for research in that area (see
"Electromagnetic fields, leukaemia and DNA damage", SiS24).
Now,
new research findings make that suggestion a great
deal more plausible.
A ‘breakthrough’ in identifying mechanisms?
Researchers
at the University of Rome in Italy led by Mario
Barteri in the Chemistry Department report striking
changes in a solution of an enzyme after exposure to
RF radiation from mobile phones. This is the first
time such a simple, reproducible, in vitro system
has been devised to study the effects of EMFs.
The
enzyme, acetylcholine esterase, involved in
transmitting nerve signals from the brain to the
skeletal muscle, has been purified and studied in
great detail and commercial preparations are readily
available. The researchers chose to study the
acetylcholine esterase from the electric eel.
The
enzyme was dissolved in a buffer solution in water and
identical samples were exposed to RF radiations within
the range of 915-1822 megahertz for 1 to 50 minutes,
while the control (unexposed) was wrapped securely in
aluminium foil to screen the RF radiations. A
commercial cellular phone was used as the source of RF
radiation at a specific absorption rate (SAR) of
0.51W/kg, with the mobile phone operating in the
receiving mode.
After
exposing the enzyme solution, the researchers used a
range of physical measurement techniques to
characterise the changes.
First
they passed the solutions down a gel filtration
column, which separates protein molecules by size. At
short irradiation times between 1 to 10 min, no
difference from the unexposed control was found; a
single protein peak was identified, representing the
enzyme in its usual ‘dimeric’ form consisting of two
protein units associated together. However, after 20
min or more, a new peak was formed in addition to the
old; the new peak representing the monomeric or
dissociated form of the protein. This profile remained
stable after one day at room temperature, showing that
irreversible change had taken place in the solution.
Measurements
on the rate constants of the enzyme activity similarly
indicated that up to 10 min of RF radiation exposure
had no effect, but after 20 min or more, the rate
constants changed dramatically, which was consistent
with previous findings from another laboratory
reporting increase in the enzyme activity in mice
after twenty minutes exposure to mobile phone
radiation.
This
change in the kinetic properties of the enzyme was
apparently not accompanied by change in the
three-dimensional shape (conformation) of the protein,
at least as measured by circular dichroism (a
technique for characterising the shape of molecules
based on measuring the unequal absorption of right and
left plane-polarized light).
Measurement
by X-ray scattering, however, revealed a drastic
change in the collective organisation of the protein
in solution, which suggested that a phase of
‘hydrogel’ had separated out from the main solution.
This hydrogel was made up of monomeric protein
molecules associated with lots of water molecules to
form a collective phase.
Finally,
the researchers took a scanning electron micrograph of
the control and the exposed sample, which showed up
the marked difference. The native, unexposed sample
appeared as a random suspension of enzyme molecules;
whereas the irradiated sample appeared as a highly
oriented sample with a regular periodic pattern.
No comments:
Post a Comment