V. P. Kalantaryan
Department of High Frequency Radiophysics Yerevan State University
0025 Yerevan, A.Manoogian St. 1, Armenia
Y. S. Babayan
Department of Medicinal and Biological Physics Yerevan State Medical University
0025 Yerevan, Koryun St. 2, Armenia
E. S. Gevorgyan, S. N. Hakobyan, A. P. Antonyan and P. O. Vardevanyan
Department of Biophysics
Yerevan State University
0025 Yerevan, A.Manoogian St. 1, Armenia
Abstract—The thermostability and density of water-salt solutions of DNA, irradiated by non thermal coherent millimeter electromagnetic waves with frequency 64.5GHz have been investigated using the methods of spectrophotometry and densitometry. It is shown that the thermostability of DNA and density of its solutions are increased, depending on time of irradiation. It is expected that under the influence of millimeter electromagnetic radiation the hydration of DNA and ions of Na+ that are present in solution decrease. As a result, the physicochemical characteristics of DNA are changed.
1. INTRODUCTION
At present, the low-power electromagnetic millimeter waves (MMWs) are widely used in biology, medicine, radio- and telecommunications, in various electronic devices. For example, during last years the MMWs were used along with anticancer drugs in the chemotherapy of tumor of the laboratory animals. The experiments proved that without reducing the effect of anticancer drugs, it became possible to reduce adverse toxic reaction of the organism to the drugs. However, the mechanisms of low-intensity MMWs action on biological object still remain unclear [5, 6, 8].
Currently, the concept that non-thermal effect of MMWs on biological systems is determined by the effect of MMWs on water, causing changes of bound water properties is rather acknowledged. It is known that electromagnetic radiation of extremely high frequensies (EHF) of 30–300 GHz barely penetrates living organisms and biological tissues. The EHF electromagnetic radiation is nonionizing. The energy of quanta of low-power (non-thermal) EHF radiation is less than the energy of heat motion of atoms and moleculs and appreciably less than the energy of hydrogen bonds in living organisms.
Numerous effects of influence of low intensity extra high frequency electromagnetic radiation on the level of human organism and animals, bacteria, as well as on prokaryotic and eukaryotic cells are revealed [9, 13]. The existence of selective frequency dependent effects of MMWs has been shown along with occurrence of non selective, frequency independent influence [6,11]. At present, the concept that non- thermal influence of MMWs on biosystems is being mediated by influence of water has got confirmation [7, 11]. Thus, the research of influence MMWs on structure and physical and chemical properties of water and water solutions of biological objects is essential. It is shown that rather weak physical influence including the MM-waves, impacts the properties of water solutions due to change of structure of water in an environment of the dissolved substances. Moreover, it is revealed, that functional changes of biological objects occur at irradiation of solutions of MM-waves [12].
At present, the animal and plant life is constantly being subjected to the low intensity microwave radiation (mobile phones, antennas, space communication, household appliances, etc). At the same time, the resonance frequencies of oscillations of molecular structures of biological tissues and molecular structures of water are in that frequency range too. Therefore, during their vital activity, the living organisms are constantly subjected to those electromagnetic fields influences and investigating the effect of electromagnetic waves of that range on water and biological systems could prove useful in developing certain mechanisms of protection from them.
The purpose of the work is to investigate the physical properties of DNA solutions irradiated by low-energy coherent electromagnetic MMWs with frequency of 64.5 GHz, in correspondence with resonance frequency of oscillations of hexagonal structures of water [11].
2. MATERIALS AND METHODS
In this work, DNAs from Calf thymus, rat liver and tumour sarcoma 45 (S-45) have been used. All samples of DNA studied in a standard citrate-salt solution 0.1 × SSC (1 × SSC = 0.15M NaCl + 0.015M Na-citrate), at presence of 10−5 M EDTA, pH = 7.3, ionic strength of solution is [Na+] = 0.0195 M. DNA from a liver of rats and from tumor S-45 have been allocated at the Institute of Fine Organic Chemistry (IFOC) (Armenia). The contents of proteins in DNA preparations of a liver of healthy animals (h-DNA) was 1.5 ± 0.2%, and in DNA from S-45 (s-DNA) was 1.3 ± 0.2%, that implies to pure DNA preparation standards.
Maxima of absorption of DNA at melting are received on spec- trophotometer PYE UNICAM-SP8-100 (England), in thermostatic cells. At DNA melting quartz cuvettes hermetically closed by teflon corks, by length of an optical way 1 cm were used. Melting of DNA was carried out at continuous heating DNA solutions with help of pro- grammed device Temperature Controller SP 876 (England), with a speed of 0.25 grade/minutes. Measurements were carried out in an in- terval of change of temperature 25◦C ≤ T ≤ 95◦C. Values of absorption were deduced on the monitor of micro calculator Hewlett Packard 97S I/O. Melting of each sample of DNA repeated 6 times. Melting curves were constructed as it is described in work [14]. Melting parameters — Temperature Tm and width of melting interval ∆T of each DNA were averaged on six measurements.
On the basis of the normalized integral melting curves the method of numerical differentiation receives differential melting curves (DMC) as it is described in work [3]. Density of water, 0.1 × SSC and DNA solutions with sensitivity was determined on dencitometer DMA 4500 Anton Paar (USA), with resolutions 10−5 g/cm3.
The irradiation of solutions by MM-waves was carried out in a special glass bulb. Solutions from above are closed by transparent fine chlorvinil membranula for radiation. Thickness of the irradiated sample did not exceed 1mm. For irradiation of MMWs source of extra high frequencies was applied, generator G4-142 (Russian made), working on the basis of a back wave lamp. On an output of the generator there was a cone-shaped radiating antenna. Stability of frequency of the generator was ±0.05%. The irradiation of samples was carried out at room temperature, in a mode of amplitude modulation of frequency of 1 Hz, incident power density on a sample at frequency of 64.5GHz was ∼ 50μW/cm2, the sample was placed in the far zone of antenna.
3. RESULTS AND DISCUSSION
The research was conducted on the exposure of MMWs on the thermostability of DNA, purified from the liver of healthy rats (h- DNA) and Sarcoma tumor 45 (S-45) in water solutions. The irradiation of the samples was carried out at room temperature, the power flux density at frequency of 64.5GHz was ∼ 50 microwatt/cm2. The DNA water solutions, prepared for spectrophotometer measurements, have been irradiated for 30, 40, 60, 90, 120 min. respectively. The melting curves have been obtained both, just after irradi curve of melting, magnitudes of Tm and ∆T do not depend on the storing time of the irradiated DNA.
Figure 1. Melting curvesof DNA Figure 2. Curve of depen- from sarcoma 45 irradiated for 90 dence of irradiated for 90 min min (1) and non-irradiated (2). and non-irradiated DNA densi-
ties on temperature.
Figure 1 shows melting curves of (1) irradiated during 90 min., and (2) non-irradiated S-45 DNA and h-DNA respectively. Depending on
Table 1. Temperature and range of DNA melting obtained from of healthy rats liver and tumor sarcoma 45.
2010-Kalantaryan-mmwave-and-DNA-Yerevan