Effects of moderate static magnetic fields on the lipogenesis and lipolysis in different genders of Caenorhabditis elegans

With the rapid development of magnetic technology, the biological effects of moderate static magnetic fields (SMFs) have attracted increasing research interest due to their potential medical diagnosis and treatment application. The present study explored the effects of moderate SMFs on the lipid metabolism of Caenorhabditis elegans (C. elegans) in different genders including male, female, and hermaphrodite. We found that the fat content was significantly decreased by moderate SMFs in wild-type N₂ worms, which was associated with their development stages. The diameters of lipid droplets in N₂ worms, him-5 worms, and fog-2 worms were greatly decreased by 19.23%, 15.38%, and 23.07% at young adult stage under 0.5 T SMF, respectively. The mRNA levels of lipolysis related genes atgl-1 and nhr-76 were significantly up-regulated by SMF exposure, while the mRNA levels of the lipogenesis related genes fat-6, fat-7, and sbp-1 were down-regulated by SMF, whereas the concentration of β-oxidase was increased. There was a slight effect of SMF on the mRNA levels of β-oxidation related genes. Moreover, the insulin and serotonin pathway were regulated by SMF, instead of the TOR pathway. In wild-type worms, we found that their lifespan was prolonged by exposure to 0.5 T SMF. Our data suggested that moderate SMFs could significantly modify the lipogenesis and lipolysis process in C. elegans in a gender and development stage-dependent manner, which could provide a novel insight into understanding the function of moderate SMFs in living organisms.

Electrochemical study of the effect of radiofrequency on glutamate oxidase activity using a glutamate oxidase-based biosensor

A biosensor based on glutamate oxidase (GluOx) was developed to measure glutamate concentration. The main function of this type of biosensor is related to the structure and catalytic activity of GluOx. Since radiofrequency, as the widest spectrum of electromagnetic fields, can affect the catalytic activity and structure of GluOx, in this study, the effect of these fields on the analytical parameters of the fabricated biosensor was investigated. To build the biosensor a sol-gel solution of chitosan and native GluOx were prepared and then immobilized on the surface of the platinum electrode. Similarly, to investigate the effect of radiofrequency fields on the analytical parameters of the biosensor, instead of the native GluOx, irradiated GluOx was used to build the biosensor. To evaluate the biosensor responses, cyclic voltammetry experiments were performed and voltammograms were considered as biosensor responses. To determine the analytical parameters including detection limit, linear range, and saturation region of the responses, calibration curves were drawn for each of the biosensors. Also the long-term stability and selectivity of the fabricated biosensor were evaluated. Thereafter, the optimum pH and temperature for each of these two biosensors were examined. The results showed that radiofrequency waves harmed the detection and response of biosensors in the saturation region, while they had little effect on the linear region. Such results could be due to the effect of radiofrequency waves on the structure and function of glutamate oxidase. In general, the results indicate that when a glutamate oxidase-based biosensor is used to measure glutamate in radiofrequency fields, corrective coefficients for this type of biosensor should be considered to accurately measure glutamate concentration.

Effects of synonymous mutations on kinetic properties and structure of firefly luciferase: Molecular dynamics simulation, molecular docking, RNA folding, and experimental study

Although synonymous mutations have long been thought to lack striking results, a growing body of research shows these mutations have highly variable effects. In this study, the impact of synonymous mutations in the development of thermostable luciferase was investigated using a combination of experimental and theoretical approaches. Using bioinformatics analysis, the codon usage features in the Lampyridae family's luciferases were studied and four synonymous mutations of Arg in luciferase were created. An exciting result was that the analysis of kinetic parameters showed a slight increase in the thermal stability of the mutant luciferase. AutoDock Vina, %MinMax algorithm, and UNAFold Server were used to perform molecular docking, folding rate, and RNA folding, respectively. Here, it was assumed that in the region (Arg337) with a moderate propensity for coil, synonymous mutation altered the rate of translation, which in turn may lead to a slight change in the structure of the enzyme. According to the molecular dynamics simulation data, local minor global flexibility is observed in the context of the protein conformation. A plausible explanation is that this flexibility may strengthen hydrophobic interactions due to its sensitivity to a molecular collision. Accordingly, thermostability originated mainly from hydrophobic interaction.

A resonant cavity system for exposing cell cultures to intense pulsed RF fields

The IEEE and ICNIRP had specified a maximum permissible exposure for instantaneous peak electric field of 100 kV/m. However, no rationale was given for this limit. A novel exposure system was designed through a detailed process of analytical analysis, numerical modelling and prototype testing. The system consists of a cylindrical re-entrant resonant cavity that can achieve an electric field strength of more than 100 kV/m with an input power of 200 W. The working of the system was evaluated in simulation and experiment in terms of scattering parameters, electric field distributions and specific absorption rate. The system was then used to carry out in-vitro exposures of a human lymphoid cell line (GG0257) to a 1195 MHz signal at 53 dBm peak power and a pulse width of 550 ns at a range of interpulse intervals to identify heating-induced changes in cell viability. The proposed system offers high Q value of 5920 in unloaded condition which was reduced to 57 when loaded with 12 ml of cell culture but still offering 67 kV/m of the field intensity. Using the system for the exposure of GG0257 cells lasting 18 min, interpulse intervals of 11 μs or less caused a reduction in the number of viable cells and a corresponding increase in necrotic cells. For a shorter exposure duration of 6 min, the reduction in cell viability was seen at interpulse intervals of 5.5 μs or less. The designed exposure system is well capable of handling high intensity electric fields. Temperature measurements with a fibre optic probe and temperature sensitive labels showed that changes in viability were associated with temperature increases above 46 °C. This novel exposure system is an efficient means to investigate the possible relationship between peak field intensity and biological effects to provide a rationale behind the maximum exposure limit of 100 kV/m.

Colloidal graphene oxide enhances the activity of a lipase and protects it from oxidative damage: Insights from physicochemical and molecular dynamics investigations

Physical adsorption of lipase from Thermomyces lanuginosus onto single-layer sheets of graphene oxide (GO) was studied using the response surface methodology to evaluate the physicochemical factors - temperature, pH, ionic strength, and concentration - affecting the enzymatic activity and the immobilization efficiency. The immobilization efficiency and the activity of the enzyme were inversely proportional to each other. Specifically, higher pH values increased the immobilization efficacy, but produced changes in the aggregation state and secondary structure of the enzyme, thus decreasing its activity. Lower pH values, in turn, reduced the immobilization efficacy, but increased the activity of the adsorbed lipase. The adsorbed and the free lipase were followed during 600 ns and 3.5 μs, respectively, in molecular dynamics (MD) simulations. MD trajectories showed that irreversible adsorption freezes the enzyme in a state with a correctly opened catalytic cavity, while the active site remains without a direct interaction with the GO adsorbent. In contrast to the interfacial activation of lipases in a hydrophobic environment, where the catalytic pocket attaches to the hydrophobic surface, the adsorption onto GO made the active site of the lipase accessible by altering the tertiary structure of the enzyme, leading to a higher catalytic efficiency. Experimental investigations confirmed that the physical adsorption onto GO induces tertiary structure changes in the lipase and protects it from H₂O₂ by accepting the oxidative damage upon itself. In summary, the physical adsorption of the lipase onto GO is mainly affected by pH and could possibly provide a spreadable and robust catalytic interface for biotechnological applications.

An isolate of Potato Virus X capsid protein from N. benthamiana: Insights from homology modeling and molecular dynamics simulation

Since Potato Virus X (PVX) is easily transmitted mechanically between their hosts, its control is difficult. We have previously reported new isolate of this virus (PVX-Iran, GenBank Accession number FJ461343). However, the molecular basis of resistance breaking activity and its relation to capsid protein structure are still not well-understood. SDS-PAGE, ELISA, Western blot and RT-PCR molecular examinations were performed on the inoculated plants Nicotiana benthamiana. The pathological symptoms were related to the PVX isolate. The capsid protein (CP) structure were modeled based on homology and subjected to three independent 80 ns molecular dynamics minimization (GROMACS, OPLS force field) in the SPC water box. The RMSD, RMSF, SASA, and electrostatic properties were retrieved from the trajectories. Flexibility and hydrophilic nature of the N-terminal residues (1-34) of solvated CP could be observed in conformational changes upon minimization. The obtained structure was then docked with NbPCIP1 using ClusPro 2.0. The strong binding affinity of these two proteins (≈-16.0 Kcal mol-1) represents the formation of inclusion body and hence appearance of the symptoms.

Real-time assessment of possible electromagnetic-field-induced changes in protein conformation and thermal stability

Previous studies on possible interactions of radiofrequency electromagnetic fields (RF EMFs) with proteins have suggested that RF EMFs might affect protein structure and folding kinetics. In this study, the isolated thermosensor protein GrpE of the Hsp70 chaperone system of Escherichia coli was exposed to EMFs of various frequencies and field strengths under strictly controlled conditions. Circular dichroism spectroscopy was used to monitor possible structural changes. Simultaneously, temperature was recorded at each point of observation. The coiled-coil part of GrpE has been reported to undergo a well-defined and fully reversible folding/unfolding transition, thus facilitating the differentiation between thermal and non-thermal effects of RF EMFs. Any direct effect of EMF on the conformation and/or stability would result in a shift of the conformational equilibrium of the protein at a given temperature. Possible immediate (t ≤ 0.1 s) and delayed (t ≥ 30 s) effects of RF EMFs were investigated with sinusoidal signals of 0.1, 1.0, and 1.9 GHz at various field strengths up to 5.0 kV/m and with GSM signals at 0.3 kV/m in the protein solution. Taking the overall uncertainty of the experimental system into account, possible RF EMF-induced shifts in the conformational equilibrium of less than 1% of its total range might have been detected. The results obtained with the different experimental protocols indicate, however, that the conformational equilibrium of GrpE is insensitive to electromagnetic fields in the tested range of frequency and field strength.

Effects of 940 MHz EMF on bioluminescence and oxidative response of stable luciferase producing HEK cells

Oxidative stress and response are among EMF mechanisms of action; the absorbed dose and ability of cells to respond might be summarized by the intracellular luciferase activity.