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1.
Belova NA  Lednev VV 《Biofizika》2000,45(6):1108-1111
We determined the dependence of the effect of weak combined magnetic field (CMF) tuned to Ca2+ resonance (Ca(2+)-CMF) on the rate of gravitropic response in apical segments (25 mm long) excised from the 4-day-old seedlings of flax (Linum bienne) on the amplitude and frequency of the alternating component of Ca(2+)-CMF. The results indicate that test-systems derived from plant and animal sources are affected by Ca(2+)-CMF via an identical mechanism.  相似文献   

2.
Ermakov AM  Lednev VV 《Biofizika》2010,55(4):715-719
The effects of weak combined magnetic fields adjusted to the parametric resonance for Ca2+ and K+ and extremely weak alternating magnetic field on the metamorphosis of the meal-worm beetle Tenebrio molitor have been studied. It was shown that the exposure of pupas of insects to all above-indicated types of fields stimulates the metamorphosis. However, after the exposure to weak combined magnetic fields adjusted to the parametric resonance for Ca2+ and K+, the number of insects with anomalies increases, which is not observed by the action of the weak alternating magnetic field.  相似文献   

3.
Belova NA  Lednev VV 《Biofizika》2000,45(6):1102-1107
It is shown that the rate of gravitropic response in the segments of stems excised from millet, flax and clover seedlings may be considerably activated or inhibited by the application of weak combined magnetic fields tuned to the parametric resonance for Ca2+ or K+, correspondingly.  相似文献   

4.
Ermakov  A. M.  Lednev  V. V. 《Biophysics》2010,55(4):633-636
The effects of weak combined magnetic fields adjusted to the parametric resonance for Ca2+ and K+ and extremely weak alternating magnetic field on the metamorphosis of the mealworm beetle Tenebrio molitor have been studied. It was shown that the exposure of pupas of insects to all above-indicated types of fields stimulates the metamorphosis. However, after the exposure to weak combined magnetic fields adjusted to the parametric resonance for Ca2+ and K+, the number of insects with anomalies increases, which is not observed by the action of the weak alternating magnetic field.  相似文献   

5.
The influence of extremely weak alternating magnetic fields (EW AMF) directed colinearly to the static Earth magnetic field on the rate of regeneration of planarians and the rate of gravitropic response in the stem segments of flax has been studied. The value of bioeffects of EW AMF is determined by the parameter gamma B(AC)/f, where y is the gyromagnetic ratio of the magnetic moments induced by the orbital movements of electrons in atoms, and B(AC) and f correspond to magnetic induction and frequency of the alternating magnetic component. It was shown that the magnitude of bioeffects depends on the amplitude (at fixed 1000 Hz - frequency) and frequency (at fixed 192 nT - amplitude) of the alternating component. Maxima of bioeffects are observed at gamma B(AC)/f = 0.9; 2.75, and minor maxima gamma B(AC)/f = 4.5; 6.1. The bioeffects are absent at gamma B(AC)/f = 1.8, 3.8, 5.3, 6.7. The positions of the maxima and minima of bioeffects correspond to the theoretical prediction (at gamma = 14000 Hz/microT). Primary targets for the EW AMF of this type are the magnetic moments induced by the orbital movements of electrons in atoms.  相似文献   

6.
We investigated the effects of weak combined magnetic fields (MFs) produced by superimposing a constant MF (in the range 30 - 150 µT) and an alternating MF (100 or 200 nT) on cytokine production in healthy Balb/C male mice exposed 2 h daily for 14 days. The alternating magnetic field was a sum of several frequencies (ranging from 2.5 - 17.5 Hz). The frequencies of the alternating magnetic field were calculated formally based on the cyclotron resonance of ions of free amino acids (glutamic and aspartic acids, arginine, lysine, histidine, and tyrosine). The selection of different intensity and frequency combinations of constant and alternating magnetic fields was performed to find the optimal characteristics for cytokine production stimulation in immune cells. MF with a constant component of 60 μT and an alternating component of 100 nT, which was a sum of six frequencies (from 5 to 7 Hz), was found to stimulate the production of tumor necrosis factor-α, interferon-gamma, interleukin-2, and interleukin-3 in healthy mouse cells and induce cytokine accumulation in blood plasma. Then, we studied the effect of this MF on tumor-bearing mice with solid tumors induced by Ehrlich ascite carcinoma cells by observing tumor development processes, including tumor size, mouse survival rate, and average lifespan. Tumor-bearing mice exposed to a combined constant magnetic field of 60 μT and an alternating magnetic field of 100 nT containing six frequencies showed a strong suppression of tumor growth with an increase in survival rate and enhancement of average lifespan.  相似文献   

7.
Exposure to ELF magnetic field tuned to Zn inhibits growth of cancer cells   总被引:2,自引:0,他引:2  
The effects of ELF alternating magnetic fields tuned to Zn(2+) on the growth of cancer cells with different status of p53 were investigated using a cell proliferation assay. Human cancer cells HeLa (cervix cancer, p53(+/+)), Saos-2 and Saos-2-His-273 (osteosarcoma, p53(-/-) and p53 His-273 mutant, respectively), H1299tTA and H1299tTA-His175 (lung carcinoma, p53(-/-) and p53 His-175 mutant), and normal human fibroblasts VH-10 (p53(+/+)) were used. Exposure parameters were calculated for the first harmonic of Zn(2+) based either on the magnetic parametric resonance (MPR) model of Lednev or the ion parametric resonance (IPR) model of Blanchard and Blackman. ELF exposure was for 72 and 96 h. The vertical alternating field was 20 Hz at amplitudes of either 38.7 or 77.4 microT (peaks, IPR or MPR, respectively). The vertical static magnetic field was 43 microT, and the horizontal static magnetic field was zeroed. Treatments of cells with PRIMA-1 and gamma-rays were used as positive controls. Growth inhibition was observed in cells after exposure to ELF at 38.7 microT. Inhibition of HeLa, VH-10, and Saos-2-His-273 cells was statistically significant, P=0.0003, 0.02, and 0.006, respectively. No consistent ELF effects following exposure 77.4 microT were seen. PRIMA-1 inhibited the growth of all cell lines with the strongest effect in mutant p53-carrying cell line H1299tTA-His175. The effects of gamma-rays were relatively weak, suggesting that the cell proliferation assay under conditions employed in this study is not very sensitive to apoptosis. In conclusion, ELF under conditions of exposure tuned to Zn(2+) according to the IPR model inhibited the growth of cancer and normal cells. No clear relationship of the observed growth inhibition to p53 status was found. Further experiments, using complementary techniques, are required to test whether p53 reactivation by ELF is feasible.  相似文献   

8.
The influence of extremely weak alternating magnetic fields (EW AMF) directed collinearly to the static Earth magnetic field on the rate of regeneration of planarians and the rate of gravitropic response in the stem segments of flax has been studied. The value of bioeffects of EW AMF is determined by the parameter γB AC/f, where γ is the gyromagnetic ratio of the magnetic moments induced by the orbital movements of electrons in atoms, and B AC and f correspond to magnetic induction and frequency of the alternating magnetic component. It was shown that the magnitude of bioeffects depends on the amplitude (at fixed 1000 Hz — frequency) and frequency (at fixed 192 nT — amplitude) of the alternating component. Maxima of bioeffects are observed at γB AC/f = 0.9; 2.75, and minor maxima γB AC/f = 4.5; 6.1. The bioeffects are absent at γB AC/f =1.8, 3.8, 5.3, 6.7. The positions of the maxima and minima of bioeffects correspond to the theoretical prediction (at γ = 14000 Hz/μT). Primary targets for the EW AMF of this type are the magnetic moments induced by the orbital movements of electrons in atoms.  相似文献   

9.
It was shown that preliminary treatment of the protein component (histone H3, protamine sulfate, polyarginine) of a DNA-protein complex with weak combined (42 microT) and low-frequency (3.5-5.0 Hz) alternating (0.06 microT) magnetic fields adjusted formally to the cyclotron resonance of amino acid ions charged under natural conditions leads to substantial changes in complex formation and formation of complexes of a different type than without treatment.  相似文献   

10.
A new detection system for weak, extremely low frequency (ELF) magnetic fields based on bioluminescence of the autotrophic dinoflagellate Gonyaulax sp. is presented. Due to its sensitivity to external factors, this biological system has already been thoroughly investigated and used for various biological research. In our study, the system was first tested for its capacity to respond to weak ELF magnetic fields (50 Hz, 11.5 mT; 50 Hz, 1.2 mT). After its sensitivity was established, the system was used to test the parametric resonance model proposed by Lednev in 1991. Our results seem to be consistent with the model predictions, especially when monitoring real-time effects of the exposure.  相似文献   

11.
The effects of magnetic fields of extremely low frequency (ELF, 21 microT r.m.s.) on cells of different Escherichia coli K12 strains and human lymphocytes were studied by the method of anomalous viscosity time dependence (AVTD). Within the frequency range of 6-24 Hz, two resonance-type frequency windows with maximal effects at 9 Hz and 16 Hz were observed in response of GE499 strain. Only one frequency window with maximum effect at 8.5 Hz was found for GE500 cells. These data along with previously obtained for two other E. coli strains, AB1157 and EMG2, indicate that frequency windows are dependent on genotype of cells exposed to ELF. Resonance-type effects of ELF were also observed in human lymphocytes in frequency windows around 8 and 58 Hz. These ELF effects differed significantly between studied donors, but were well reproducible in independent experiments with lymphocytes from the same donors. The frequency windows in response of E. coli strains and human lymphocytes to ELF significantly overlapped suggesting that the same targets may be involved in this response. We compared the frequency windows with predictions based on the ion cyclotron resonance (ICR) model and the magnetic parametric resonance model. These models predicted effects of ELF magnetic fields at the 'cyclotron' frequencies of some ions of biological relevance. According to the ICR model, ELF effects should be also observed at harmonics of cyclotron frequencies and, contrary, parametric resonance model predicted effects at subharmonics. While we observed coincidence of each experimental resonance frequency with predictions of one of these two models, all experimentally defined effective frequency windows were in good agreement with relatively narrow frequency ranges of both harmonics and subharmonics for natural isotopes of Na, K, Ca, Mg, and Zn ions. The experimental data support idea that both harmonics and subharmonics of several biologically important ions are involved in frequency-dependent ELF effects in cells of different types.  相似文献   

12.
Kim SK  Chang SC  Lee EJ  Chung WS  Kim YS  Hwang S  Lee JS 《Plant physiology》2000,123(3):997-1004
Exogenously applied brassinolide (BL, 10(-9)-10(-5) M) increased gravitropic curvature in maize (Zea mays) primary roots. The BL-enhanced gravitropic curvature was clearly promoted in the presence of indole-3-acetic acid (IAA, 10(-10)-10(-8) M), indicating that BL is interactive with IAA during the gravitropic response. The interactive effect between BL and IAA was completely diminished by treatment of p-chlorophenoxy isobutric acid, an auxin action antagonist. The activation of the gravitropic response by BL in the absence and in the presence of IAA was nullified by application of 2, 3,5-triiodobenzoic acid, a polar auxin transport inhibitor. The data indicate that brassinosteroids (BRs) might be involved in auxin-mediated processes for the gravitropic response. Gas chromotography-selected ion-monitoring analysis revealed that maize primary roots contained approximately 0.3 ng g(-1) fresh weight castasterone as an endogenous BR. Exogenously applied castasterone also increased the gravitropic response of maize roots in an IAA-dependent manner. This study provides the first evidence, to our knowledge, for occurrence and gravitropic activity of BRs in plant roots.  相似文献   

13.
The effect of extremely weak alternating magnetic fields of various types with the amplitudes δ of 2 μT on the heart rate variability in humans was studied. Volunteers were placed in a large-volume coil system (2ω2ω2 m), which provided exposure of the whole body to extremely weak alternating magnetic fields uniform in their amplitude. It was shown for the first time that the exposure to such fields could both increase and decrease the magnitude of stress in humans. In particular, the field tuned to the nuclear spins of hydrogen atoms (amplitude, 1.6 μT and frequency, 76 Hz) decreased the Baevsky stress index, whereas the field tuned to the magnetic moments formed by the orbiting electrons in some atoms (amplitude, 0.192 μT and frequency, 3000 Hz) increased this index. These results provide a possible explanation for the mechanisms of adverse effects caused by extremely weak alternating magnetic fields of certain types of both technogenic and natural origins on the human cardiovascular system.  相似文献   

14.
Ethylene is known to interact with auxin in regulating stem growth, and yet evidence for the role of ethylene in tropic responses is contradictory. Our analysis of four mutants of tomato (Lycopersicon esculentum) altered in their response to gravity, auxin, and/or ethylene revealed concentration-dependent modulation of shoot gravitropism by ethylene. Ethylene inhibitors reduce wild-type gravicurvature, and extremely low (0.0005-0.001 microliter L-1) ethylene concentrations can restore the reduced gravitropic response of the auxin-resistant dgt (diageotropica) mutant to wild-type levels. Slightly higher concentrations of ethylene inhibit the gravitropic response of all but the ethylene-insensitive nr (never-ripe) mutant. The gravitropic responses of nr and the constitutive-response mutant epi (epinastic) are slightly and significantly delayed, respectively, but otherwise normal. The reversal of shoot gravicurvature by red light in the lz-2 (lazy-2) mutant is not affected by ethylene. Taken together, these data indicate that, although ethylene does not play a primary role in the gravitropic response of tomato, low levels of ethylene are necessary for a full gravitropic response, and moderate levels of the hormone specifically inhibit gravicurvature in a manner different from ethylene inhibition of overall growth.  相似文献   

15.
The fundamental physical mechanisms of resonance action of an extremely weak (40 nT) alternating magnetic field at the cyclotron frequency combined with a weak (40 μT) static magnetic field, on living systems are analyzed in the present work. The experimental effects of such sort of magnetic fields were described in different papers: the very narrow resonant peaks in electrical conductivity of the aqueous solutions in the in vitro experiments and the biomedical in vivo effects on living animals of magnetic fields with frequencies tuned to some amino acids. The existing experimental in vitro data had a good repeatability in different laboratories and countries. Unfortunately, for free ions such sort of effects are absolutely impossible because the dimensions of an ion rotation radius should be measured by meters at room temperature and at very low static magnetic fields used in all the above experiments. Even for bound ions these effects should be also absolutely impossible from the positions of classic physics because of rather high viscosity of biological liquid media (blood plasma, cerebrospinal liquid, cytoplasm). Only modern quantum electrodynamics of condensed media opens the new ways for solving these problems. The proposed article is devoted to analysis of quantum mechanisms of these effects.  相似文献   

16.
Low-intensity magnetic fields alter operant behavior in rats   总被引:1,自引:0,他引:1  
The present study demonstrates that operant behavior is affected by a combination of a 60-Hz magnetic field and a magnetostatic field 2.6 X 10(-5) T (about half the geomagnetic field). Rats exposed to this combination for 30 min consistently exhibited changes in the rate and pattern of responding during the differential reinforcement of low rate (DRL) component of a multiple fixed ratio (FR) DRL reinforcement schedule. By contrast, there were no measurable changes following exposure to the static field alone or to the oscillating field alone, even with a 10-fold increase in intensity (5 X 10(-5) to 5 X 10(-4) Trms). A cyclotron resonance mechanism has been suggested as a possible explanation for the observation that weak static magnetic fields modify the response of in vitro brain tissue to low-frequency magnetic fields. The choice of static field intensity Bo and frequency nu in the present study follows from the cyclotron resonance condition nu = (1/2 pi)(q/m)Bo, for singly charged lithium, an element in extensive use in the clinical treatment of affective disorders in humans. The present research is consistent with a cellular cyclotron resonance mechanism and tends to imply a functional dependence of behavior on the geomagnetic field.  相似文献   

17.
Organisms exposed to a combination of weak, parallel static and alternating magnetic fields show a distinct response when the frequency of the alternating component is formally equal to the cyclotron frequencies for Ca2+ or other biologically important ions. It is impossible to explain the observable phenomenon through a magnetoinduced drift of the ions, as the Lorentz force is too small to change ionic movements. In similar conditions, a resonance-like response arises when the alternating field is tuned to the Larmor frequency for nuclear-spin magnetic moments. The mechanism of these phenomena is also still unclear. In this communication, arguments are presented whereby both types of effect can be treated in a unified context, for which the existence of ion-specific magnetic dipoles must be postulated.  相似文献   

18.
Novikov VV  Fesenko EE 《Biofizika》2001,46(2):235-241
It was shown that weak combined magnetic fields (constant field 25-130 microT; variable field 0.01-0.2 microT; the range of effective frequencies of the alternating component 1-10 Hz) substantially increase the rate of hydrolysis of some proteins and peptides (eight various sequences). The concentration dependence of the dynamics of the process and the dependence of the magnitude of the effect on the parameters of the magnetic field. It was found that: (1) the effect is transmitted through a solvent preliminarily treated by magnetic fields and (2) the effect occurs in the presence of inhibitors of proteases and enzymes inactivating peroxides (catalase and horse radish peroxidase with substrate).  相似文献   

19.
We have chosen E. coli K92, which produces the alternating structure alpha(2-8)neuNAc alpha(2-9)neuNAc as a model system for studying bacterial polysaccharide biosynthesis. We have shown that the polysialyltransferase encoded by the K92 neuS gene can synthesize both alpha(2-8) and alpha(2-9) neuNAc linkages in vivo by 13C-nuclear magnetic resonance analysis of polysaccharide isolated from a heterologous strain containing the K92 neuS gene. The K92 polysialyltransferase is associated with the membrane in lysates of cells harboring the neuS gene in expression vectors. Although the enzyme can transfer sialic acid to the nonreducing end of oligosaccharides with either linkage, it is unable to initiate chain synthesis without exogenously added polysialic acid. Thus, the polysialyltransferase encoded by neuS is not sufficient for de novo synthesis of polysaccharide but requires another membrane component for initiation. The acceptor specificity of this polysialyltransferase was studied using sialic acid oligosaccharides of various structures as exogenous acceptors. The enzyme can transfer to the nonreducing end of all bacteria polysialic acids, but has a definite preference for alpha(2-8) acceptors. Gangliosides containing neuNAc alpha(2-8)neuNAc are elongated, whereas monsialylated gangliosides are not. Disialylgangliosides are better acceptors than short oligosaccharides, suggesting a lipid-linked oligosaccharide may be preferred in the elongation reaction. These studies show that the K92 polysialyltransferase catalyzes an elongation reaction that involves transfer of sialic acid from CMP-sialic acid to the nonreducing end of two different acceptor substrates.  相似文献   

20.
B S Selinsky  P L Yeagle 《Biochemistry》1984,23(10):2281-2288
Phosphorus nuclear magnetic resonance spectra of sarcoplasmic reticulum membranes from rabbit muscle and of recombined membranes containing the calcium-dependent adenosinetriphosphatase (Ca-ATPase) of sarcoplasmic reticulum reveal two distinguishable, overlapping resonances. One resonance resembles a normal phospholipid bilayer resonance, and the other is much broader. The broader component is not seen in protein-free phospholipid vesicles. In recombined membranes of the Ca-ATPase, the intensity found in the broad component was proportional to the concentration of protein in the vesicles. The two-component spectra are interpreted to arise from at least two different domains of phospholipids, one of which is motionally restricted by the Ca-ATPase. Phospholipids exchange between these two domains at a rate less than 10(3) s-1. A model for protein-lipid interactions in membranes containing the Ca-ATPase is proposed in which some of the phospholipid head groups of the membrane interact directly with the protein.  相似文献   

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