This paper studies the effects of electromagnetic fields (EMF), specifically with circular electric field polarization, on the structure of Hemoglobin. Nearly all of the previous studies are based on linearly-polarized waves. But our comparative study based on a novel dual-polarized waveguide exposure device, shows that the EMF effects on macromolecules such as hemoglobin are polarization-dependent, and that circularly-polarized EMFs with the same incident power density can have significantly stronger effects on the structure of Hemoglobin. A novel dual-polarized exposure device is employed, followed by intrinsic fluorescence spectroscopy, UV–Vis spectroscopy, and far UV Circular Dichroism Spectroscopy, to show that the helical content is significantly reduced under circular as compared to linear polarization. This corresponds to a certain unwinding effect through the circularly-polarized EMF. The physical basis for the observed results is discussed together with implications for further research.
All content in this area was uploaded by Siyavash Shabani on Jun 28, 2020
Content may be subject to copyright.
A preview of the PDF is not available
... In modern life, electromagnetic fields are widely employed, influencing living organisms. The functionality of protein systems (including enzymatic ones) can be altered under the action of magnetic [2] and electromagnetic fields [3][4][5][6][7][8][9][10]. In this way, in previous studies, we demonstrated that electric fields, triboelectrically induced by liquid flow through polymeric pipes of thermal stabilization coils, influence the adsorbability of the horseradish peroxidase (HRP) enzyme protein onto mica substrates [5][6][7]. ...
... Lopes et al. [9] found that 2450 MHz [11] microwave radiation can cause a significant (up to >80%) loss in the HRP enzymatic activity after a 0.5 h treatment at 60 • C and 60 W microwave power. Hamedi et al. demonstrated partial unfolding of adult hemoglobin (HbA) after exposure to a 940 MHz circularly polarized electromagnetic field [8]. As regards HRP, a 52 mT static magnetic field was also shown to impact its enzymatic activity and optimum pH by inducing changes in its structure [2]. ...
... Namely, background electromagnetic radiation is concentrated upon its reflection from the interior surface of the half-sphere, leading to a change in the spatial topology of this radiation. Electromagnetic fields are known to influence proteins [1,[3][4][5][6][7][8][9][10]. Previously, we demonstrated that even ultra-weak electromagnetic fields, whose intensity is comparable to that of the background (of 10 −12 W/cm 2 power density) electromagnetic fields of a non-standard specific topology-such as knotted electromag-netic fields-can induce substantial alterations in protein adsorption properties [4]. ...
External electromagnetic fields are known to be able to concentrate inside the construction elements of biosensors and bioreactors owing to reflection from their surface. This can lead to changes in the structure of biopolymers (such as proteins), incubated inside these elements, thus influencing their functional properties. Our present study concerned the revelation of the effect of spherical elements, commonly employed in biosensors and bioreactors, on the physicochemical properties of proteins with the example of the horseradish peroxidase (HRP) enzyme. In our experiments, a solution of HRP was incubated within a 30 cm-diameter titanium half-sphere, which was used as a model construction element. Atomic force microscopy (AFM) was employed for the single-molecule visualization of the HRP macromolecules, adsorbed from the test solution onto mica substrates in order to find out whether the incubation of the test HRP solution within the half-sphere influenced the HRP aggregation state. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) was employed in order to reveal whether the incubation of HRP solution within the half-sphere led to any changes in its secondary structure. In parallel, spectrophotometry-based estimation of the HRP enzymatic activity was performed in order to find out if the HRP active site was affected by the electromagnetic field under the conditions of our experiments. We revealed an increased aggregation of HRP after the incubation of its solution within the half-sphere in comparison with the control sample incubated far outside the half-sphere. ATR-FTIR allowed us to reveal alterations in HRP’s secondary structure. Such changes in the protein structure did not affect its active site, as was confirmed by spectrophotometry. The effect of spherical elements on a protein solution should be taken into account in the development of the optimized design of biosensors and bioreactors, intended for performing processes involving proteins in biomedicine and biotechnology, including highly sensitive biosensors intended for the diagnosis of socially significant diseases in humans (including oncology, cardiovascular diseases, etc.) at early stages.
... Electric [26][27][28][29][30][31], magnetic [32][33][34][35][36] and electromagnetic [37][38][39][40][41][42][43][44][45][46][47] fields are known to affect enzymes. In many papers, the effects of pulsed electric [26][27][28][29][30][31] and electromagnetic [42] fields on enzymes are considered. ...
Glycerol is a usable component of heat-transfer fluids, and is thus suitable for the use in microchannel-based heat exchangers in biosensors and microelectronic devices. The flow of a fluid can lead to the generation of electromagnetic fields, which can affect enzymes. Herein, by means of atomic force microscopy (AFM) and spectrophotometry, a long-term effect of stopped flow of glycerol through a coiled heat exchanger on horseradish peroxidase (HRP) has been revealed. Samples of buffered HRP solution were incubated near either the inlet or the outlet sections of the heat exchanger after stopping the flow. It has been found that both the enzyme aggregation state and the number of mica-adsorbed HRP particles increase after such an incubation for 40 min. Moreover, the enzymatic activity of the enzyme incubated near the inlet section has been found to increase in comparison with that of the control sample, while the activity of the enzyme incubated near the outlet section remained unaffected. Our results can find application in the development of biosensors and bioreactors, in which flow-based heat exchangers are employed.
Energy efficiency has always been an inherent problem of microwave heating. In this work, the higher heating efficiency of the elliptically polarized microwave electric field is investigated via MD simulations, aiming to examine the multidirectional polarization effect during microwave heating. The MD results show that the heating efficiency growth rates of EtOH, AcOH, DMSO, H2O, and DMF are 3.17%, 3.92%, 4.14%, 5.00%, and 27.06% sequentially larger with the elliptically polarized microwave electric field (EF) than those with the linearly polarized microwave EF. Energy analyses indicate that the utilization rate of microwave energy would be increased of the elliptically polarized microwave EF with the same electric field intensities. The higher decay speed of the rotation autocorrelation function curves of elliptically polarized EF presents that the sample molecules do have a more frequent rotational motion to align with the varying polarization directions. Additionally, dielectric properties analysis gave the relation between the heating efficiency growth rate and the loss tangent of the samples. This microwave heating method is expected to be a new route to improve the microwave heating efficiency.
The molecular mechanism of the microwave nonthermal effect is still not clear. This work investigated the spatial orientation and kinetic energy of active site collision of carnosine, a natural bioactive dipeptide, under the weak microwave irradiation using the molecular dynamics simulation. Our results showed the influences of the temperature, microwave intensity, microwave frequency, and microwave polarization mode (linear polarization and circular polarization) on the spatial orientation and kinetic energy of active site collision of carnosine. First, under the constant intensity and frequency of linear polarization microwave irradiation, the increment of the collision probability between the 6N atom of carnosine and the 28H atom of the other carnosine at effective space angle decreases from 85.0% to 3.5% with increasing temperature. Second, with the increase of microwave intensity, the change of spatial orientation and kinetic energy becomes more and more significant. However, the change of circular polarization microwaves on the spatial orientation and kinetic energy of collision is weaker than that of linear polarization. Third, under the constant intensity of linear polarization microwave irradiation, the collision probability between the 6N atom and the 28H atom at effective space angle decreases from 70.2% to 14.7% with increasing frequency. Finally, under the microwave polarization, the spatial orientation and kinetic energy of molecular collision are changed, which is summarized as the microwave postpolarization effect (MWPPE). The dependence of MWPPE on temperature, microwave intensity, microwave frequency, and polarization mode is very complicated. In the end, this effect can provide a new insight into the molecular mechanism of the microwave nonthermal effect.
Our present study concerns the influence of the picosecond rise-time-pulsed electromagnetic field, and the impact of nanosecond pulsed pressure on the aggregation state of horseradish peroxidase (HRP) as a model enzyme. The influence of a 640 kV/m pulsed electromagnetic field with a pulse rise-time of ~200 ps on the activity and aggregation state of an enzyme is studied by the single-molecule atomic force microscopy (AFM) method. The influence of such a field is shown to lead to aggregation of the protein and to a decrease in its enzymatic activity. Moreover, the effect of a shock wave with a pressure front rise-time of 80 ns on the increase in the HRP aggregation is demonstrated. The results obtained herein can be of use in modeling the impact of electromagnetic and pressure pulses on enzymes and on whole living organisms. Our results are also important for taking into account the effect of pulsed fields on the body in the development of drugs, therapeutic procedures, and novel highly sensitive medical diagnosticums.
Conformational alterations of bovine hemoglobin (Hb) upon sequential addition of glyoxal over a range of 0-90% v/v were investigated. At 20% v/v glyoxal, molten globule (MG) state of Hb was observed by altered tryptophan fluorescence, high ANS binding, existence of intact heme, native-like secondary structure as depicted by far-UV circular dichroism (CD) and ATR-FTIR spectra as well as loss in tertiary structure as confirmed by near-UV CD spectra. In addition, size exclusion chromatography analysis depicted that MG state at 20% v/v glyoxal corresponded to expanded pre-dissociated dimers. Aggregates of Hb were detected at 70% v/v glyoxal. These aggregates of Hb had altered tryptophan environment, low ANS binding, exposed heme, increased β-sheet secondary structure, loss in tertiary structure, enhanced thioflavin T (ThT) fluorescence and red shifted Congo Red (CR) absorbance. On incubating Hb with 30% v/v glyoxal for 0-20 days, advanced glycation end products (AGEs) were detected on day 20. These AGEs were characterised by enhanced tryptophan fluorescence at 450 nm, exposure of heme, increase in intermolecular β-sheets, enhanced ThT fluorescence and red shift in CR absorbance. Comet assay revealed aggregates and AGEs to be genotoxic in nature. Scanning electron microscopy confirmed the amorphous structure of aggregates and branched fibrils of AGEs. The transformation of α-helix to β-sheet usually alters the normal protein to amyloidogenic resulting in a variety of protein conformational disorders such as diabetes, prion and Huntington's.
This book collects the revised lectures held at Capri (Italy) in the period 2-6 May, 1988 in occasion of the International Course on "Worldwide Nonionizing Radiation Safety Standards: Their Rationales and Problems". The Course was organized by IRECE (Institute for Research in Electromagnetism and Electronic Components) of CNR (Italian National Council for Research) and was directed by professors Giorgio Franceschetti and Om P. Gandhi. The idea for this course arose from the continuing wide disparity in the electromagnetic (EM) radiation safety standards worldwide, and the confusion that this has caused in the public mind. The safety guidelines in the western countries have been nearly three orders of magnitude greater than the safety levels in the Eastern European countries. Even though the former have been slightly reduced and the latter have been increased somewhat in recent years, there is still a wide gap in the EM safety standards that are used. With the ever increasing use of EM energy the public is becoming increasingly aware of and concerned about the potential biohazards of EM fields. This problem is compounded by inadequate knowledge of nonthermal mechanisms of interaction of EM fields with biological systems. The lecturers for the Course were the recognized leaders in their respective areas within the discipline of Biological Effects of Electromagnetic Fields.
The effects of electromagnetic fields (EMFs) radiation at the frequency of 940 MHz on the structure and function of human adult and fetal hemoglobin (HbA and HbF) were studied. After extraction and purification of HbA and HbF, the oxygen absorption values for exposed and unexposed HbA and HbF to EMF were compared. The slope of oxygen absorption curve for exposed HbA was increased while that for HbF was decreased compare to those before EMF exposing. Furthermore, the oxygen absorption saturation values were changed from 3.4-5.1 and from 5.1-3.1 mg l-1 , respectively for HbA and HbF after exposing to EMF. The UV-Vis, circular dichroism and fluorescence spectroscopy confirmed the quaternary structural changes of both proteins after EMF exposure. So that, the structural transition of HbA from tense to relaxed state caused an increasing in oxygen absorption; whilst in HbF, transition from relaxed to tense state was occurred and therefore oxygen absorption was decreased.
Solutions of Acid Phosphatase have been exposed to 9.375 GHz microwave radiation under intrinsically unstable conditions (pH 5.6, T = 60°C), and the enzyme deactivation process has been analyzed by evaluating the deactivation curve (i.e. the timecourse of the enzyme specific activity). Unmodulated (CW) and square wave (SQW) amplitude modulated radiation has been used for exposures with absorbed power density (SAR) in the sample varying from 160 up to 480 mW/g. In order to state if the perturbation proceduces a significant effect on the deactivation process, we have adopted a criterion based on the analysis of the whole deactivation curve. Two limiting deactivation curves have been determined that envelop all the interpolating curves produced in the reference runs: the applied perturbation is judged to yield an appreciable effect whenever the corresponding deactivation curve lies outside this range. Exposures at SAR levels exceeding 280 mW/g affect the deactivation process of Acid Posphatase: the overall result is a surprising stabilization of the enzyme toward thermal deactivation.
Microwaves near 42 GHz are found to influence the growth of Saccharomyces cerevisiae. The growth is measured photometrically in stirred aqueous culture. The microwave effect occurs and saturates above a threshold intensity < 10 mW/cm2, excluding any explanation based on microwave heating. A surprisingly strong frequency dependence is observed, with resonances as narrow as 8 MHz. These results confirm the existence of a nonthermal resonant microwave sensitivity in biology; they suggest yet unknown tuned systems triggering yet unknown biological actions.
Currently, the biological effects of nonionizing electromagnetic fields (EMFs) including radiofrequency (RF) radiation have been the subject of numerous experimental and theoretical studies. The aim of this study is to evaluate the possible biological effects of mobile phone RF (940MHz, 15V/m and SAR=40mW/kg) on the structure of calf thymus DNA (ct DNA) immediately after exposure and 2h after 45min exposure via diverse range of spectroscopic instruments. The UV-vis and circular dichroism (CD) experiments depict that mobile phone EMFs can remarkably cause disturbance on ct DNA structure. In addition, the DNA samples, immediately after exposure and 2h after 45min exposure, are relatively thermally unstable compared to the DNA solution, which was placed in a small shielded box (unexposed ct DNA). Furthermore, the exposed DNA samples (the DNA samples that were exposed to 940MHz EMF) have more fluorescence emission when compared with the unexposed DNA, which may have occurred attributable to expansion of the exposed DNA structure. The results of dynamic light scattering (DLS) and zeta potential experiments demonstrate that RF-EMFs lead to increment in the surface charge and size of DNA. The structure of DNA immediately after exposure is not significantly different from the DNA sample 2h after 45min exposure. In other words, the EMF-induced conformational changes are irreversible. Collectively, our results reveal that 940MHz can alter the structure of DNA. The displacement of electrons in DNA by EMFs may lead to conformational changes of DNA and DNA disaggregation. Results from this study could have an important implication on the health effects of RF-EMFs exposure. In addition, this finding could proffer a novel strategy for the development of next generation of mobile phone.