Q95141569
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The effects of 50 Hz magnetic fields on sulphate- reducing bacteria viability were studied electrochemically. Two types of graphite electrodes (pyrolytic and glassy carbon) covered with whole bacterial cells behind a dialysis membrane were used for electrochemical measurements. We found about 15% decrease of reduction peak current density (which indicates desulphurization activity of the bacterial cells - their metabolic activity) on cyclic voltammograms after magnetic field exposure compared to the control samples. We suppose that the magnetic field does not influence the metabolic activity (desulphurization) of sulphate-reducing bacteria but most probably causes bacterial death.
50 Hz magnetic fields effects on Sulfate Reducing Bacteria (SRB) viability were studied by colony forming units (CFU) counting. We found a 15% decrease of CFU number after magnetic field exposure (B=7.1 mT, f=50 Hz, t=24 min) compared to the control samples. These results are in good agreement with our previous work on other bacterial strains. The magnetic field effects on SRB are relatively large for small magnetic fields. The data correlations have been subjected to a simple physical chemical analysis, yielding surprisingly large estimates for the characteristic magnetic reaction susceptibility, even when the entire bacterium is assumed to be the direct target of interaction of the magnetic ac fields for the exposures in the time range from 3-24 min.
- MeSH
- Bacteria růst a vývoj metabolismus účinky záření MeSH
- elektromagnetická pole škodlivé účinky MeSH
- kinetika MeSH
- mikrobiální viabilita účinky záření MeSH
- oxidace-redukce MeSH
- počet mikrobiálních kolonií MeSH
- sírany metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Adsorpcí biopolymerů na povrch titanu a titanem dopovaných uhlovodíkových povlaků se zvyšuje optická drsnost, tloušťka a index lomu povrchové vrstvy. Fibrinogen se lépe adsorbuje na povrchu titanu, který je upraven leštěním a leptáním, nežli na povrchu pouze leštěném. Nejlépe se adsorbuje na povrch uhlovodíkových povlaků dopovaným titanem, které byly deponované reaktivním magnetronovým naprašováním v optimálním poměru Ti0,38 - C0,62 a Ti0,09 - C0,91. Takto upravené povrchy dentálních implantátů by měly urychlit jejich oseointegraci a vhojení. Na povrch titanu se lépe adsorbují jednořetězové pyrimidinové oligodeoxynukleotidy (TTC)12, nežli purinové (AAG)12. Dvojšroubovicový duplex (TTC)12. (AAG)12 neovlivňuje optické vlastnosti povrchu titanu a patrně se na povrch neadsorbuje.
Adsorption of biopolymers at the titanium and titanium carbide surface increases the optical roughness as well as the thickness and refractive index of the surface layer. Fibrinogen is better adsorbed at the titanium surface which is treated by polishing and etching than at the surface treated only by polishing. The best adsorption of fibrinogen was observed at the titanium carbide surface prepared by plasma-enhanced chemical vapour deposition, the optimal ratio was Ti0,38 - C0,62 a Ti0,09 - C0,91. The surface of dental implants treated by this way should speed up their osseointegration and healing. The single stranded pyrimidine oligodeoxynucleotides (TTC)12 are better adsorbed at the titanium surface than the purine oligodeoxynucleotides (AAG)12. The double-helical duplex (TTC)12. (AAG)12 has no effect on the optical properties of the titanium surface and probably is not adsorbed there.
- MeSH
- adsorpce MeSH
- biokompatibilní materiály normy MeSH
- biosenzitivní techniky využití MeSH
- fibrinogen MeSH
- financování organizované MeSH
- mikroskopie atomárních sil využití MeSH
- oligonukleotidy MeSH
- osteoblasty ultrastruktura MeSH
- osteointegrace fyziologie MeSH
- techniky in vitro MeSH
- titan terapeutické užití MeSH
- zubní implantáty MeSH
Effect of electromagnetic low frequency fields was studied on mice. We analyzed level of protein in brain of mouse. The levels of c-Jun and c-Fos in brains were measured using Western-blot techniques. Female and male laboratory mice were exposed for 4 days to magnetic field (Bm = 2 mT, f = 50 Hz). The exposure took place in cylindrical coil at laboratory temperature. After the experiment they were sacrificed and the level of protein c-Jun and c-Fos in different parts of brain were estimated. The expression of c-Fos was not affected by magnetic field on the other hand the expression of c-Jun decreased after magnetic field exposure. The results did not depend on sex of mice.
- MeSH
- elektřina MeSH
- elektromagnetická pole MeSH
- mozek účinky záření MeSH
- myši inbrední ICR MeSH
- myši MeSH
- proteiny chemie MeSH
- protoonkogenní proteiny c-fos biosyntéza MeSH
- protoonkogenní proteiny c-jun biosyntéza MeSH
- radiační účinky MeSH
- sexuální faktory MeSH
- teplota MeSH
- western blotting MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
The high ability of self-association of nucleic acid components leads to a two-dimensional (2D) condensation at electrode surfaces. The driving force of the process resides in the intermolecular interactions, such as dispersion forces, hydrogen bonding or electrostatic interactions. In this study, the condensation of 5-halogen cytosine derivatives (5-fluorocytosine, 5-bromocytosine and 5-iodocytosine) at the hanging mercury drop electrode was investigated to evaluate the influence of the different types of intermolecular interactions in the phenomenon. All of these derivatives form 2D capacitance pits, but in distinct conditions of pH, concentrations and temperature. Dispersion forces are identified as the main contributor to the 2D condensation of 5-iodocytosine, while for 5-fluorocytosine this is hydrogen bonding in hemiprotonated dimers. The third derivative, 5-bromocytosine, is an intermediate case between the two formers.
Stripping voltammetric determination of purine bases in the presence of copper ions at mercury, amalgam, or carbon-based electrodes has recently been utilized in analysis of DNA or synthetic oligodeoxynucleotides (ODNs). Here we report on copper-enhanced label-free anodic stripping detection of guanine and adenine bases in acid-hydrolyzed DNA at anodically oxidized boron-doped diamond electrode (AO-BDDE). The AO-BDDE was successfully applied in a three-electrode microcell in which an approximately 50 microL drop of the analyte solution can be efficiently stirred during the accumulation step by streaming of an inert gas. Accelerated mass transport due to the solution motion in the presence of copper resulted in enhancement of the guanine oxidation signal by about 2 orders of magnitude (compared to accumulation of the analyte from still solution not containing copper), allowing an easy detection of approximately 25 fmol of the ODNs. The proposed technique is shown to be suitable for a determination of purine (particularly guanine) content in DNA samples. Applications of the technique in magnetic bead-based DNA assays (such as hybridization with DNA sequences exhibiting asymmetrical distribution of purine/pyrimidine nucleotides between the complementary strands or monitoring of amplification of specific DNA fragments in a duplex polymerase chain reaction) are demonstrated.
- MeSH
- bor chemie MeSH
- diamant chemie MeSH
- DNA-dependentní DNA-polymerasy metabolismus MeSH
- DNA MeSH
- elektrochemie MeSH
- elektrody MeSH
- financování organizované MeSH
- hydrolýza MeSH
- kationty chemie MeSH
- kyseliny chemie MeSH
- měď chemie MeSH
- oligonukleotidy chemie MeSH
- oxidace-redukce MeSH
- puriny chemie MeSH
- sekvence nukleotidů MeSH
