In vitro studies of the influence of ELF electromagnetic fields on the activity of soluble and insoluble peroxidase

Current Strategies for Real-Time Enzyme Activation

Enzyme activation is a powerful means of achieving biotransformation function, aiming to intensify the reaction processes with a higher yield of product in a short time, and can be exploited for diverse applications. However, conventional activation strategies such as genetic engineering and chemical modification are generally irreversible for enzyme activity, and they also have many limitations, including complex processes and unpredictable results. Recently, near-infrared (NIR), alternating magnetic field (AMF), microwave and ultrasound irradiation, as real-time and precise activation strategies for enzyme analysis, can address many limitations due to their deep penetrability, sustainability, low invasiveness, and sustainability and have been applied in many fields, such as biomedical and industrial applications and chemical synthesis. These spatiotemporal and controllable activation strategies can transfer light, electromagnetic, or ultrasound energy to enzymes, leading to favorable conformational changes and improving the thermal stability, stereoselectivity, and kinetics of enzymes. Furthermore, the different mechanisms of activation strategies have determined the type of applicable enzymes and manipulated protocol designs that either immobilize enzymes on nanomaterials responsive to light or magnetic fields or directly influence enzymatic properties. To employ these effects to finely and efficiently activate enzyme activity, the physicochemical features of nanomaterials and parameters, including the frequency and intensity of activation methods, must be optimized. Therefore, this review offers a comprehensive overview related to emerging technologies for achieving real-time enzyme activation and summarizes their characteristics and advanced applications.

Rotating magnetic field as tool for enhancing enzymes properties - laccase case study

The aim of this study was to analyse the effect of rotating magnetic field (RMF) exposition on the fungal laccase catalytic properties. The results obtained in the study revealed that RMF may positively alter the laccase activity. A significant increase in activities of 11%, 11%, and 9% were observed at 10 Hz, 40 Hz and 50 Hz, respectively. Exposure of laccase to the rotating magnetic field resulted in its increased activity at broader pH range and a slight shift in optimum pH from 4.0 to 4.5 at RMF with frequency 20 Hz. The results show that the enzyme activity, stability, and optimum pH can be significantly altered depending on the characteristic of the applied RMF. Application of rotating magnetic field opens a new way for controlling and directions of enzyme-based bioprocessing.

Low-amplitude, high-frequency electromagnetic field exposure causes delayed and reduced growth in Rosa hybrida

It is now accepted that plants perceive high-frequency electromagnetic field (HF-EMF). We wondered if the HF-EMF signal is integrated further in planta as a chain of reactions leading to a modification of plant growth. We exposed whole small ligneous plants (rose bush) whose growth could be studied for several weeks. We performed exposures at two different development stages (rooted cuttings bearing an axillary bud and 5-leaf stage plants), using two high frequency (900MHz) field amplitudes (5 and 200Vm(-1)). We achieved a tight control on the experimental conditions using a state-of-the-art stimulation device (Mode Stirred Reverberation Chamber) and specialized culture-chambers. After the exposure, we followed the shoot growth for over a one-month period. We observed no growth modification whatsoever exposure was performed on the 5-leaf stage plants. When the exposure was performed on the rooted cuttings, no growth modification was observed on Axis I (produced from the elongation of the axillary bud). Likewise, no significant modification was noted on Axis II produced at the base of Axis I, that came from pre-formed secondary axillary buds. In contrast, Axis II produced at the top of Axis I, that came from post-formed secondary buds consistently displayed a delayed and significant reduced growth (45%). The measurements of plant energy uptake from HF-EMF in this exposure condition (SAR of 7.2 10(-4)Wkg(-1)) indicated that this biological response is likely not due to thermal effect. These results suggest that exposure to electromagnetic field only affected development of post-formed organs.

Does the magnetic field of a magnetic stirrer in an optical aggregometer affect concurrent platelet aggregation?

Platelets are subjected to extremely low frequency electromagnetic fields during standard aggregometry measurements owing to the use of a magnetic stir bar in the instrument. This study evaluates the effects of this magnetic field exposure on platelet aggregation by comparing the results obtained in a modified aggregometer. Blood samples from healthy volunteers were anticoagulated using citrate or heparin. Platelet-rich plasma (PRP) samples were prepared. A mechanical stirring device was attached to the aggregometer instead of the magnetic stir bar system. The PRP samples were stirred using a stirring rod tip that did not produce any magnetic fields in one channel of the aggregometer; in the other channel, a stirring rod carrying a small magnet at its tip was used. As a result, a magnetic field in the extremely low frequency range and in the amplitude range of 1.9-65 mT was applied to the platelets assigned to the channel where the magnetic stirring rod tip was used. Aggregation was induced using adenosine diphosphate (ADP), collagen, or epinephrine. The slopes, maximum aggregation values, and areas under the aggregation curves were compared between the magnetic and neutral stirring rod tip groups. For samples stirred with the magnetic stirring rod tip, a significant decrease was observed in 12 of the 14 parameters evaluated for aggregations induced with ADP or collagen compared to the neutral stirring rod tip, regardless of the method used for anticoagulation. This observation indicates that the magnetic stir bars used in standard aggregometry may significantly alter aggregation parameters and platelets may be possible targets of electromagnetic fields.

Investigation of the effects of 50 Hz magnetic fields on platelet aggregation using a modified aggregometer

PURPOSE

Electromagnetic fields have various effects on intracellular calcium levels, free oxygen radicals and various enzymes. The platelet activation pathway involves an increase in intracellular calcium levels and protein kinase C activation; and free oxygen radicals play a mediating role in this pathway. This study investigated whether 1 mT and 6 mT, 50 Hz magnetic fields had any effects on platelet aggregation.

MATERIALS AND METHODS

Blood from healthy volunteers was anticoagulated with either citrate or heparin. Each sample was divided in half and assigned to exposure and control groups. Platelet rich plasma samples in the exposure group were exposed to a 1 mT or a 6 mT, 50 Hz magnetic field for 1.5 or 1 h, respectively. The samples from both exposure and control groups were simultaneously evaluated using a modified optical aggregometer. Adenosine-diphosphate, collagen, and epinephrine were used as inducing agents. The slopes of the aggregation curve, the maximum values and the areas under the curves were recorded and compared.

RESULTS

A significant effect was observed only in the 1 mT-citrate group. It was found that magnetic field exposure significantly increased the maximum values and slopes of the collagen-induced aggregations.

CONCLUSIONS

It was found that magnetic field exposure has an activating effect on platelet aggregation.

Response surface analysis of nano-ureases from Canavalia ensiformis and Cajanus cajan

Ureases isolated from leguminous sources, Canavalia ensiformis and Cajanus cajan were immobilized onto gold nanoparticles (nano-ureases). Optimization of the urease immobilization was carried using response surface methodology based on Central Composite Design. Immobilization efficiency of nano-urease from C. ensiformis and C. cajan were found to be 215.10% and 255.92%, respectively. The methodology adopted has deviation of 2.56% and 3.01% with respect to experimental values in case of C. ensiformis and C. cajan, respectively. Nano-urease from C. cajan has broad physico-chemical parameters with pH optimum from 7.1 to 7.3 and temperature optimum from 50 to 70°C. Nano-urease from C. ensiformis has sharp pH and temperature optima at 7.3 and 70°C, respectively. Fourier transform infra-red spectroscopy has revealed involvement of groups viz. amino, glycosyl moiety, etc. in urease immobilization onto gold nano-particles. Transmission and scanning electron micrographs revealed that arrangement of urease onto gold nano-particles from C. ensiformis was uniform while it was localized in case of C. cajan. Nano-urease from C. ensiformis has higher specificity and catalysis toward urea as compared to nano-urease from C. cajan. Nano-ureases from both sources are equally stable for 6 months under dried conditions and can be used for 10 washes.

Lactose nano-probe optimized using response surface methodology

A lactose nano-probe has been developed by immobilization of PsBGAL onto gold nanoparticles (AuNps). It is helpful for severe lactose intolerants for quality check of lactose hydrolyzed milk and estimation of hidden lactose present in variety of food products. Optimization of PsBGAL immobilization onto AuNps using spacer arm (cysteamine-glutaraldehyde) was carried out by response surface methodology (Box-Behnken design). The process has led to immobilization of enzyme onto AuNps with an efficiency of 140.81%. AuNp-PsBGAL was characterized using transmission electron microscopy, scanning electron microscopy and Fourier transform infrared spectroscopy. Immobilized enzyme showed broad temperature and pH optima and a significant enhancement in catalytic efficiency (V(max)/K(m)) with respect to soluble PsBGAL. AuNp-PsBGAL was stable under dried conditions than wet conditions for 6 months with loss of 10.2% and 87.53%, respectively. It has reusability of over five batchwise uses, with almost no loss in activity. Hill's coefficient was found to be 1.71 corresponding to lactose concentration ranging from 0.1% to 2.0%.

The effect of electromagnetic radiation (550 – 850 nm) on l-Lactate dehydrogenase kinetics

PURPOSE

This work is based on our earlier research of the Resonant Recognition Model (RRM), where we have proposed that protein activation is electromagnetic in its nature. In this study we investigated experimentally the possibility of modulating the protein activity by the electromagnetic radiation of the specific frequency. The concept is studied here by applying a visible light radiation to example of 1-Lactate Dehydrogenase enzyme (LDH).

MATERIALS AND METHODS

The selected LDH example is radiated by monochromatic visible light in a frequency range predicted computationally by the RRM. The kinetics of the irradiated LDH is measured by continuous monitoring of the NADH absorption at 340 nm.

RESULTS

A comparative analysis of the LDH enzyme activity before and after the electromagnetic field (EMF) exposures is performed. It was found that the LDH activity is selectively increased only by the radiation at the particular wavelengths of 595 nm and 828 nm. These experimentally determined wavelengths of the applied EMF are within the range predicted by the RRM.

CONCLUSIONS

Results reveal the LDH activity was modulated by the EMF exposures at the computationally predicted frequencies. The RRM concept presented provides new insights into proteins susceptibility to perturbation by electromagnetic radiation and possibility to program, predict, design and modify proteins and their bioactivity.

Effects of 100 GHz radiation on alkaline phosphatase activity and antigen-antibody interaction

Equipment that generates microwave radiation (MWR) spanning the frequency range of 300 MHz-100 GHz is becoming more common. While MWR lacks sufficient energy to break chemical bonds, the disagreement as to whether MWR exposure is detrimental to cellular dysfunction may be difficult to clarify using complex systems such as whole animals, cells, or cell extracts. Recently, the high frequency range of terahertz (THz) radiation has been explored and sources of radiation and its detectors have been developed. THz radiation is associated with the frequency interval from 100 GHz to 20 THz and constitutes the next frontier in imaging science and technology. In the present study, we investigated the effect of radiation in the low frequency THz range (100 GHz) on two defined molecular interactions. First, the interaction of soluble or immobilized calf alkaline phosphatase with the substrate p-nitrophenylphosphate and second, the interaction between an antibody (mouse monoclonal anti-DNP) and its antigen (DNP). Irradiation of enzyme either prior to addition of substrate or during the enzymatic reaction resulted in small but significant reductions in enzyme activity. These differences were not observed if the enzyme had previously been immobilized onto plastic microwells. Exposure of immobilized antigen to radiation did not influence the ability of the antigen to interact with antibody. However, irradiation appeared to decrease the stability of previously formed antigen-antibody complexes. Our data suggest that 100 GHz radiation can induce small but statistically significant alterations in the characteristics of these two types of biomolecular interactions.

Stabilization of beta-galactosidase (from peas) by immobilization onto amberlite MB-150 beads and its application in lactose hydrolysis

The soluble PsBGAL (from Pisum sativum ) is extremely unstable with loss of over 80% in enzyme activity within 24 h at 4 degrees C when the protein concentration was lower than 0.1 mg/mL. Enzyme immobilization onto Amberlite MB-150 beads (diameter = 5 microm) greatly stabilized the enzyme preparation, with almost no loss for 12 months at room temperature (27 degrees C). Enzyme (21.9 microg) was immobilized by 62.56% onto activated 100 mg of Amberlite MB-150 beads using 4% glutaraldehyde, at pH 6.0 (50 mM, sodium phosphate buffer). Statistical analysis carried out by ANOVA revealed that all parameters used during immobilization were equally important at P < 0.05 (level of significance). An approach toward commercial exploitation of Amberlite-PsBGAL especially in lactose hydrolysis was anticipated due to improved physicochemical properties including broad optimum pH and temperature, with a K(m) of 4.11 +/- 0.21 mM for lactose. Amberlite-PsBGAL hydrolyzed 64.57 and 69.18% of lactose present in milk and milk whey, respectively, within 10 h (at room temperature). Immobilized enzyme has reusability of over 10 batchwise uses, with almost no loss in activity. The easy accessibility of enzyme source, ease of its immobilization on Amberlite, lower cost of Amberlite, enhanced stability of Amberlite-PsBGAL, and comparable lactose hydrolysis in milk and milk whey described here make it a suitable product for future applications at laboratory and industrial scale.

Modulation of the catalytic activity of free and immobilized peroxidase by extremely low frequency electromagnetic fields: dependence on frequency

A study of the influence of electromagnetic fields (EMF) of various frequencies, from 50 up to 400 Hz, on the catalytic activity of soluble and insoluble horseradish peroxidase (POD) was carried out. To simulate the conditions in which the enzyme operates in vivo, the POD was immobilized by entrapment on a gelatin membrane or by covalent attachment on a nylon graft membrane. The rate of inactivation of the soluble POD was found to exhibit positive and negative interactions with the 1 mT applied magnetic field, with an optimum positive effect at 130 Hz. The immobilized PODs, on the contrary, do not exhibit negative interactions, but show a maximum positive interaction at 150 Hz when entrapped and at 170 Hz when covalently attached. At 50 Hz and at frequencies higher than 250 Hz no effects were observed with insoluble POD. The optimum frequency of positive interaction between the EMF and the catalytic activity of the insoluble enzymes is shifted with respect to that of the soluble enzymes towards higher frequencies, the size of the shifts being dependent on the intensity of the physical forces involved in the immobilization process.

Influence of 400, 900, and 1900 MHz electromagnetic fields onLemna minor growth and peroxidase activity

Increased use of radio and microwave frequencies requires investigations of their effects on living organisms. Duckweed (Lemna minor L.) has been commonly used as a model plant for environmental monitoring. In the present study, duckweed growth and peroxidase activity was evaluated after exposure in a Gigahertz Transversal Electromagnetic (GTEM) cell to electric fields of frequencies 400, 900, and 1900 MHz. The growth of plants exposed for 2 h to the 23 V/m electric field of 900 MHz significantly decreased in comparison with the control, while an electric field of the same strength but at 400 MHz did not have such effect. A modulated field at 900 MHz strongly inhibited the growth, while at 400 MHz modulation did not influence the growth significantly. At both frequencies a longer exposure mostly decreased the growth and the highest electric field (390 V/m) strongly inhibited the growth. Exposure of plants to lower field strength (10 V/m) for 14 h caused significant decrease at 400 and 1900 MHz while 900 MHz did not influence the growth. Peroxidase activity in exposed plants varied, depending on the exposure characteristics. Observed changes were mostly small, except in plants exposed for 2 h to 41 V/m at 900 MHz where a significant increase (41%) was found. Our results suggest that investigated electromagnetic fields (EMFs) might influence plant growth and, to some extent, peroxidase activity. However, the effects of EMFs strongly depended on the characteristics of the field exposure.

Effect of extremely low frequency magnetic fields on calpain activation

The effects of low intensity, low frequency magnetic fields (MFs) on catalytic activity of the calcium dependent protease calpain was determined following the enzyme activation both in "in vitro" and "in vivo" conditions. We have observed that a 0.3 mT MF induces a significant increase in the requirement of the protease for this metal ion. This change is detectable at low [Ca(2+)] and disappears when the level of Ca(2+) is raised to saturating amounts. The observed effects are not due to transient MF(-) induced conformational changes occurring in calpain, but to direct effects of the MF on Ca(2+) ions, which become less available for the binding sites present in calpain. Altogether, these results indicate that exposure to low intensity, low frequency MFs alters the intracellular Ca(2+) "availability," thereby modifying the related cell response.