Characterisation of weak magnetic field effects in an aqueous glutamic acid solution by nonlinear dielectric spectroscopy and voltammetry

BACKGROUND: Previous reports indicate altered metabolism and enzyme kinetics for various organisms, as well as changes of neuronal functions and behaviour of higher animals, when they were exposed to specific combinations of weak static and alternating low frequency electromagnetic fields. Field strengths and frequencies, as well as properties of involved ions were related by a linear equation, known as the formula of ion cyclotron resonance (ICR, abbreviation mentioned first by Liboff). Under certain conditions already a aqueous solution of the amino acid and neurotransmitter glutamate shows this effect. METHODS: An aqueous solution of glutamate was exposed to a combination of a static magnetic field of 40 μT and a sinusoidal electromagnetic magnetic field (EMF) with variable frequency (2–7 Hz) and an amplitude of 50 nT. The electric conductivity and dielectric properties of the solution were investigated by voltammetric techniques in combination with non linear dielectric spectroscopy (NLDS), which allow the examination of the dielectric properties of macromolecules and molecular aggregates in water. The experiments target to elucidate the biological relevance of the observed EMF effect on molecular level. RESULTS: An ion cyclotron resonance (ICR) effect of glutamate previously reported by the Fesenko laboratory 1998 could be confirmed. Frequency resolution of the sample currents was possible by NLDS techniques. The spectrum peaks when the conditions for ion cyclotron resonance (ICR) of glutamate are matched. Furthermore, the NLDS spectra are different under ICR- and non-ICR conditions: NLDS measurements with rising control voltages from 100–1100 mV show different courses of the intensities of the low order harmonics, which could possibly indicate "intensity windows". Furthermore, the observed magnetic field effects are pH dependent with a narrow optimum around pH 2.85. CONCLUSIONS: Data will be discussed in the context with recent published models for the interaction of weak EMF with biological matter including ICR. A medical and health relevant aspect of such sensitive effects might be given insofar, because electromagnetic conditions for it occur at many occasions in our electromagnetic all day environment, concerning ion involvement of different biochemical pathways

Error analysis of implicit and exponential time integration of linear Maxwell\u27s equations

This thesis is concerned with the numerical analysis of some well-known time integration methods, such as implicit collocation methods and exponential integrators, for linear Maxwell\u27s equations in time-domain. The error analysis of time integrators is done both for continuous Maxwell\u27s equations in a semigroup theory framework and for space discrete problem obtained by discretizing Maxwell\u27s equations in space by using discontinuous Galerkin finite element method

Reduced heat transfer in saltwater by a magnetic field: do oceans have a “geomagnetic brake”?

Seawater is the major heat transporter in our global environment, covering more than two-thirds of the surface of the earth.With an average salinity of ∼3.5%, it is a moderate electric conductor, which is permanently in motion by thermal and hydrodynamicforces. The geomagnetic field exerts a Lorentz force on seawater that principally influences both the dissipation of turbulence and the flow properties by magnetic friction. Here we show by experiments on laboratory scale that convection in seawater is slowed down by an external static magnetic field and leads to a reduced heat flux resulting in an increased or decreased heat content in the volume in response to influx or drain of heat, respectively. Experimentally, the application of a vertical magnetic field of 60mT reduces the convective heat transport on the liquid-air surface within in 5min by about 8% perpendicular to the field and up to 14% parallel to it. The effect is strongly correlated with the magnetic interaction parameter of the system, which relates the magnetic to the viscous volume force. In the natural environment, the geomagnetic field is omnipresent. It is weaker by about three orders of magnitude compared with the magnetic field applied in the experiments. It has, however, an undisturbed and long-lasting impact on the convection, at low Reynolds numbers, in the large body of water in the deeper ocean below the mixed layer. There are no investigations regarding a possible contribution of this effect to natural saltwater flows, neither by proxy experiments nor by model calculations.The data presented raise the possibility that convective heat transport in the sea could be always slowed down by the geomagnetic field to a certain extent, besides it could be modulated by the geomagnetic secular variation on relatively short timescales like decades

Thermal inactivation and conformational lock studies on glucose oxidase

In this study, the dissociative thermal inactivation and conformational lock theories are applied for the homodimeric enzyme glucose oxidase (GOD) in order to analyze its structure. For this purpose, the rate of activity reduction of glucose oxidase is studied at various temperatures using b-D-glucose as the substrate by incubation of enzyme at various temperatures in the wide range between 40 and 70 �C using UV–Vis spectrophotometry. It was observed that in the two ranges of temperatures, the enzyme has two different forms. In relatively low temperatures, the enzyme is in its dimeric state and has normal activity. In high temperatures, the activity almost disappears and it aggregates. The above achievements are confirmed by dynamic light scattering. The experimental parameter ‘‘n’’ as the obvious number of conformational locks at the dimer interface of glucose oxidase is obtained by kinetic data, and the value is near to two. To confirm the above results, the X-ray crystallography structure of the enzyme, GOD (pdb, 1gal), was also studied. The secondary and tertiary structures of the enzyme to track the thermal inactivation were studied by circular dichroism and fluorescence spectroscopy, respectively. We proposed a mechanism model for thermal inactivation of GOD based on the absence of the monomeric form of the enzyme by circular dichroism and fluorescence spectroscopy

Transient effect of weak electromagnetic fields on calcium ion concentration in Arabidopsis thaliana

Background: Weak magnetic and electromagnetic fields can influence physiological processes in animals, plants and microorganisms, but the underlying way of perception is poorly understood. The ion cyclotron resonance is one of the discussed mechanisms, predicting biological effects for definite frequencies and intensities of electromagnetic fields possibly by affecting the physiological availability of small ions. Above all an influence on Calcium, which is crucial for many life processes, is in the focus of interest. We show that in Arabidopsis thaliana, changes in Ca(2+)-concentrations can be induced by combinations of magnetic and electromagnetic fields that match Ca(2+)-ion cyclotron resonance conditions. Results: An aequorin expressing Arabidopsis thaliana mutant (Col0-1 Aeq Cy+) was subjected to a magnetic field around 65 microtesla (0.65 Gauss) and an electromagnetic field with the corresponding Ca(2+) cyclotron frequency of 50 Hz. The resulting changes in free Ca(2+) were monitored by aequorin bioluminescence, using a high sensitive photomultiplier unit. The experiments were referenced by the additional use of wild type plants. Transient increases of cytosolic Ca(2+) were observed both after switching the electromagnetic field on and off, with the latter effect decreasing with increasing duration of the electromagnetic impact. Compared with this the uninfluenced long-term loss of bioluminescence activity without any exogenic impact was negligible. The magnetic field effect rapidly decreased if ion cyclotron resonance conditions were mismatched by varying the magnetic fieldstrength, also a dependence on the amplitude of the electromagnetic component was seen. Conclusion: Considering the various functions of Ca(2+) as a second messenger in plants, this mechanism may be relevant for perception of these combined fields. The applicability of recently hypothesized mechanisms for the ion cyclotron resonance effect in biological systems is discussed considering it's operating at magnetic field strengths weak enough, to occur occasionally in our all day environment

In-situ enzymatic generation of hydrogen peroxide for bleaching purposes

Bleaching detergent formulations contain environmentally unfriendly bleaching agents (perborates and percarbonates), which cause aquatic eutrophication, although without these compounds detergents are much less efficient for the washing processes. In an effort to replace these compounds, in this study, hydrogen peroxide was generated as a bleaching compound by means of enzymatic reactions. Three different pathways were investigated. The first one was the H2O2 production from glucose by glucose oxidase. The second one was the production of H2O2 from carboxymethylcellulose (CMC) by the action of both cellulase, which promotes the hydrolysis of the polymeric chain, and glucose oxidase, which oxidizes the smaller fractions to produce H2O2. Finally, H2O2 was also obtained from ethanol, which is present in liquid detergents, by the action of the enzyme alcohol oxidase. In the search for maximal peroxide production, substrate concentration and enzymatic activities were optimized. The effect of H2O2 produced in the washing process was simulated by means of a process of cotton bleaching. Although enzymatic-reaction oxidations produced higher levels of hydrogen peroxide (up to 1 g/L after 8 h), higher improvement of cotton whiteness was achieved from CMC and from ethanol. The milder conditions of temperature and pH, biodegradability and less consumption of water and energy are advantageous for enzymes as good substitutes for H2O2 precursors and make them appropriate to be considered in detergent formulations. These enzymes could be combined with other oxidative enzymes, such as peroxidases, in order to lower the required temperature and use a pH close to the neutral value during the bleaching processes

GacA is essential for Group A <i>Streptococcus </i>and defines a new class of monomeric dTDP-4-dehydrorhamnose reductases (RmlD)

The sugar nucleotide dTDP-L-rhamnose is critical for the biosynthesis of the Group A Carbohydrate, the molecular signature and virulence determinant of the human pathogen Group A Streptococcus (GAS). The final step of the four-step dTDP-L-rhamnose biosynthesis pathway is catalyzed by dTDP-4-dehydrorhamnose reductases (RmlD). RmlD from the Gram-negative bacterium Salmonella is the only structurally characterized family member and requires metal-dependent homo-dimerization for enzymatic activity. Using a biochemical and structural biology approach, we demonstrate that the only RmlD homologue from GAS, previously renamed GacA, functions in a novel monomeric manner. Sequence analysis of 213 Gram-negative and Gram-positive RmlD homologues predicts that enzymes from all Gram-positive species lack a dimerization motif and function as monomers. The enzymatic function of GacA was confirmed through heterologous expression of gacA in a S. mutans rmlD knockout, which restored attenuated growth and aberrant cell division. Finally, analysis of a saturated mutant GAS library using Tn-sequencing and generation of a conditional-expression mutant identified gacA as an essential gene for GAS. In conclusion, GacA is an essential monomeric enzyme in GAS and representative of monomeric RmlD enzymes in Gram-positive bacteria and a subset of Gram-negative bacteria. These results will help future screens for novel inhibitors of dTDP-L-rhamnose biosynthesis