Nonthermal effects of millimeter microwaves on yeast growth.
*Grundler
W*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Grundle\
r%20W%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubm\
ed_DiscoveryPanel.Pubmed_RVAbstractPlus>,
*Keilmann
F*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Keilman\
n%20F%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubm\
ed_DiscoveryPanel.Pubmed_RVAbstractPlus>
.
Weak microwave irradiation of aqueous yeast cultures was found to *affect
their growth rate in a frequency-selective manner*. Depending on frequency
(near 42 GHz), both *increases and decreases of the growth rate were
observed*. The resonance bandwidths are of the order of 0.01 GHz.
Simple *thermal effects can be excluded*. These findings support theoretical predictions of coherent *molecular oscillations activating metabolic processes*.
*J Microw Power. 1979 Dec;14(4):307-12.Links*
Determination of a thermal equivalent of millimeter microwaves in living
cells. *Dardalhon
M*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Dardalh\
on%20M%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pub\
med_DiscoveryPanel.Pubmed_RVAbstractPlus>,
*Averbeck
D*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Averbec\
k%20D%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubm\
ed_DiscoveryPanel.Pubmed_RVAbstractPlus>,
*Berteaud
AJ*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Bertea\
ud%20AJ%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pu\
bmed_DiscoveryPanel.Pubmed_RVAbstractPlus>
.
Recent microwave experiments have shown *frequency dependent influences on the growth rate of bacteria*. To determine whether microwaves are able to
affect growth (or to induce lesions in cellular DNA of yeast cells),
experiments were performed with millimeter microwaves at frequencies between 70 and 75 GHz. Saccharomyces cerevisiae cells were irradiated on millipore filter discs placed on agar plates in open petri dishes. A diploid strain of yeast (D5, Zimmerman), that is sensitive to genetic insult was used to study
the effects of temperature and of microwave irradiation on cell survival,
induction of mitotic recombination, and induction of cytoplasmic “petite”
mutations. No evidence of altered survival, impaired function, or structural
injury was seen at either frequency, even at power densities as high as 60
mW/cm2. Conventional heating had no deleterious effects until temperatures
of specimens exceeded 50 degrees C. In addition, two haploid strains of
yeast of opposite mating type were compared with respect to temperature and
microwave treatment for formation of zygotes. The elevation of temperature
due to the microwave treatment at 60 mW/cm2 and 2 mm distance was estimated to correspond to 3 degrees C.
J Microw Power. 1980 Jun;15(2):75-80.
*Response of Aspergillus nidulans and Physarum polycephalum to microwave
irradiation.*
*Mezykowski
T*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Mezykow\
ski%20T%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pu\
bmed_DiscoveryPanel.Pubmed_RVAbstractPlus>,
*Bal
J*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Bal%20J\
%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_Di\
scoveryPanel.Pubmed_RVAbstractPlus>,
*Debiec
H*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Debiec%\
20H%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed\
_DiscoveryPanel.Pubmed_RVAbstractPlus>,
*Kwarecki
K*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Kwareck\
i%20K%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubm\
ed_DiscoveryPanel.Pubmed_RVAbstractPlus>
.
The influence of microwaves on genetic processes in Aspergillus nidulans and
Physarum polycephalum was investigated. Suspensions of organisms were
exposed in the far zone to 2450-MHz waves at 10 mW/cm2 for one hour in both CW and pulsed (1 microsecond, 600 pps) fields. Spores of A. nidulans were irradiated before and during germination. No changes in survival rate or in frequency of morphological mutation were found. *Polycephalum under the
influence of CW microwaves incorporated 3H-Thymine into DNA at a rate five
times that of controls and twice that of thermal controls*. The accelerated
synthesis may reflect more efficient volume heating by microwaves, or in the
presence of microthermal gradients in suspensions, or field-specific
influences in concern with focal or volume heating.
*Z Naturforsch [C]. 1989 Sep-Oct;44(9-10):863-6.Links*
Resonant microwave effect on locally fixed yeast microcolonies. *Grundler W
*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Grundler\
%20W%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubme\
d_DiscoveryPanel.Pubmed_RVAbstractPlus>,
*Keilmann
F*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Keilman\
n%20F%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubm\
ed_DiscoveryPanel.Pubmed_RVAbstractPlus>
.
Gesellschaft für Strahlen- und Umweltforschung, Bundesrepublik Deutschland.
The microwave influence on the growth of yeast cells is studied in a novel
experimental set-up designed to observe individual cells growing for several
division cycles. The results are in accordance with *resonant
microwave-induced growth stimulation as observed in our earlier set-up *where the turbidity of a stirred suspension of cells was used as the measure of growth. The new experimental set-up is suited to decide on the proposed
triplet mechanism of resonant microwave biological effects.
*Bioelectrochem Bioenerg. 1999 Feb;48(1):177-80.Links*
The effects of radiofrequency fields on cell proliferation are non-thermal.
*Velizarov
S*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Velizar\
ov%20S%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pub\
med_DiscoveryPanel.Pubmed_RVAbstractPlus>,
*Raskmark
P*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Raskmar\
k%20P%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubm\
ed_DiscoveryPanel.Pubmed_RVAbstractPlus>,
*Kwee
S*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Kwee%20\
S%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_D\
iscoveryPanel.Pubmed_RVAbstractPlus>
.
Institute of Chemical Engineering, Bulgarian Academy of Sciences, Sofia,
Bulgaria.
The number of reports on the effects induced by radiofrequency (RF)
electromagnetic fields and microwave (MW) radiation in various cellular
systems is still increasing. Until now no satisfactory mechanism has been
proposed to explain the biological effects of these fields. One of the
current theories is that heat generation by RF/MW is the cause, in spite of
the fact that a great number of studies under isothermal conditions have
reported significant cellular changes after exposure to RF/MW. Therefore,
this study was undertaken to investigate which effect MW radiation from
these fields in combination with a significant change of temperature could
have on *cell proliferation*. The experiments were performed on the same
cell line, and with the same exposure system as in a previous work [S. Kwee,
P. Raskmark, Changes in cell proliferation due to environmental non-ionizing
radiation: 2. Microwave radiation, Bioelectrochem. Bioenerg., 44 (1998), pp.
251-255]. The field was generated by* signal simulation of the Global System
for Mobile communications (GSM) of 960 MHz*. Cell cultures, growing in
microtiter plates, were exposed in a specially constructed chamber, a
Transverse Electromagnetic (TEM) cell. The Specific Absorption Rate (SAR)
value for each cell well was calculated for this exposure system. However,
in this study the cells were exposed to the field at a higher or lower
temperature than the temperature in the field-free incubator i.e., the
temperature in the TEM cell was either 39 or 35 +/- 0.1 degrees C. The
corresponding sham experiments were performed under exactly the same
experimental conditions. *The results showed that there was a significant
change in cell proliferation in the exposed cells in comparison to the
non-exposed (control) cells at both temperatures. On the other hand, no
significant change in proliferation rate was found in the sham-exposed cells
at both temperatures*. This shows that *biological effects due to RF/MW
cannot be attributed only to a change of temperature*. Since the RF/MW
induced changes were of the same order of magnitude at both temperatures and also comparable to our previous results under isothermal conditions at 37
degrees C, cellular stress caused by electromagnetic fields could initiate
the changes in cell cycle reaction rates. *It is widely accepted that
certain classes of heat-shock proteins are involved in these stress
reactions*.
*Phys Med Biol. 2002 Nov 7;47(21):3831-9.[image: Click here to
read]<http://www.ncbi.nlm.nih.gov/entrez/utils/fref.fcgi?PrId=5350&itool=Abstrac\
tPlus-def&uid=12452574&db=pubmed&url=http://stacks.iop.org/0031-9155/47/3831>
Links*
Preliminary results on the non-thermal effects of 200-350 GHz radiation on
the growth rate of S. cerevisiae cells in microcolonies. *Hadjiloucas
S*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Hadjilo\
ucas%20S%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.P\
ubmed_DiscoveryPanel.Pubmed_RVAbstractPlus>,
*Chahal
MS*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Chahal\
%20MS%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubm\
ed_DiscoveryPanel.Pubmed_RVAbstractPlus>,
*Bowen
JW*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Bowen%\
20JW%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubme\
d_DiscoveryPanel.Pubmed_RVAbstractPlus>
.
Department of Cybernetics, The University of Reading, Whiteknights, RG6 6AY,
Berkshire, UK.
We report preliminary results from studies of *biological effects induced by
non-thermal levels of non-ionizing electromagnetic radiation*. Exponentially
growing Saccharomyces cerevisiae yeast cells grown on dry media were exposed to electromagnetic fields in the 200-350 GHz frequency range at low power density to observe possible non-thermal effects on the microcolony growth.
*Z Naturforsch [C]. 1978 Jan-Feb;33(1-2):15-22.Links*
Exposure to the electromagnetic field was conducted over 2.5 h. The data
from exposure and control experiments were grouped into either large-,
medium- or small-sized microcolonies to assist in the accurate assessment of
growth. *The three groups showed significant differences in growth between
exposed and control microcolonies*. *A statistically significant enhanced
growth rate was observed at 341 GHz*. Growth rate was assessed every 30 min via time-lapse photography. Possible interaction mechanisms are discussed, taking into account Frohlich’s hypothesis.
*Mikrobiol Z. 2004 May-Jun;66(3):51-7.Links*
[Effect of radio-frequency electromagnetic radiation on physiological
features of Saccharomyces cerevisiae strain UCM Y-517] [Article in Russian]
*Voĭchuk
SI*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Vo%C4%\
ADchuk%20SI%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPane\
l.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus>,
*Podgorskiĭ
VS*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Podgor\
ski%C4%AD%20VS%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP\
anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus>,
*Gromozova
EN*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Gromoz\
ova%20EN%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.P\
ubmed_DiscoveryPanel.Pubmed_RVAbstractPlus>
.
Effect of electromagnetic radiation (40.68 MHz) on growth characteristics of
Saccharomyces cerevisiae strain UCM Y-517 has been studied. *Reliable
increase of the specific growth rate (by 7-15%) and change of duration of
growth phases as a result of irradiation of yeast population has been shown*.
The EMR effect has been found to depend on physiological state of the
irradiated cells and composition of the irradiation performance medium:
reliable effects were found only for the cells preliminarily grown on the
dense nutrition medium in the late phase of delayed growth or on achieving
the stationary growth phase. The role of radiation term and power as well as
of temperature factor in EMR effect on the cells is discussed. *It has been
noted that the dependence of specific growth rate of yeast on the initial
density of cells population acquire the nonlinear character as affected by
EMR of radiofrequency range*.
Art Kab
“A ‘Good Student’ answers questions – but does not question answers.”
(TGF
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