Imagine cells that live in a high-gradient magnetic field (HGMF). Through what mechanisms do the cells sense a non-uniform magnetic field and how such a field changes the cell fate? We show that magnetic forces generated by HGMFs can be comparable to intracellular forces and therefore may be capable of altering the functionality of an individual cell and tissues in unprecedented ways. We identify the cellular effectors of such fields and propose novel routes in cell biology predicting new biological effects such as magnetic control of cell-to-cell communication and vesicle transport, magnetic control of intracellular ROS levels, magnetically induced differentiation of stem cells, magnetically assisted cell division, or prevention of cells from dividing. On the basis of experimental facts and theoretical modeling we reveal timescales of cellular responses to high-gradient magnetic fields and suggest an explicit dependence of the cell response time on the magnitude of the magnetic field gradient.
- MeSH
- biologická evoluce MeSH
- buněčná diferenciace MeSH
- buněčná smrt fyziologie MeSH
- časové faktory MeSH
- cytoskelet fyziologie MeSH
- kmenové buňky MeSH
- lidé MeSH
- magnetické pole * škodlivé účinky MeSH
- magnetismus metody MeSH
- membránové potenciály MeSH
- nádory patologie MeSH
- regulace genové exprese MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
The annual food and agricultural waste production reaches enormous numbers. Therefore, an increasing need to valorize produced wastes arises. Waste materials originating from the food and agricultural industry can be considered as functional materials with interesting properties and broad application potential. Moreover, using an appropriate magnetic modification, smart materials exhibiting a rapid response to an external magnetic field can be obtained. Such materials can be easily and selectively separated from desired environments. Magnetically responsive waste derivatives of biological origins have already been prepared and used as efficient biosorbents for the isolation and removal of both biologically active compounds and organic and inorganic pollutants and radionuclides, as biocompatible carriers for the immobilization of diverse types of (bio)molecules, cells, nano- and microparticles, or (bio)catalysts. Potential bactericidal, algicidal, or anti-biofilm properties of magnetic waste composites have also been tested. Furthermore, low cost and availability of waste biomaterials in larger amounts predetermine their utilization in large-scale processes.
Isolation of DNA using magnetic particles is a field of high importance in biotechnology and molecular biology research. This protocol describes the evaluation of DNA-magnetic particles binding via dynamic light scattering (DLS) and electrophoretic light scattering (ELS). Analysis by DLS provides valuable information on the physicochemical properties of particles including particle size, polydispersity, and zeta potential. The latter describes the surface charge of the particle which plays major role in electrostatic binding of materials such as DNA. Here, a comparative analysis exploits three chemical modifications of nanoparticles and microparticles and their effects on DNA binding and elution. Chemical modifications by branched polyethylenimine, tetraethyl orthosilicate and (3-aminopropyl)triethoxysilane are investigated. Since DNA exhibits a negative charge, it is expected that zeta potential of particle surface will decrease upon binding of DNA. Forming of clusters should also affect particle size. In order to investigate the efficiency of these particles in isolation and elution of DNA, the particles are mixed with DNA in low pH (~6), high ionic strength and dehydration environment. Particles are washed on magnet and then DNA is eluted by Tris-HCl buffer (pH = 8). DNA copy number is estimated using quantitative polymerase chain reaction (PCR). Zeta potential, particle size, polydispersity and quantitative PCR data are evaluated and compared. DLS is an insightful and supporting method of analysis that adds a new perspective to the process of screening of particles for DNA isolation.
Hypothermia is an effective neuroprotective strategy for acute stroke. However, in clinical practice, the induction of hypothermia is achieved through the systemic reduction of body temperature (using thermal covers or endovascular cooling devices) which results in a complex system associated in many cases to side effects. Therefore, the aim of this study was to test the magnetocaloric effect as a potential new therapeutic strategy for stroke by means of an adiabatic magnetic refrigerator device. As a first approach, we have developed a simple device to evaluate in vitro the thermodynamic behavior of different concentrations of commercial gadolinium powder as a reference magnetocaloric material. The samples, properly thermally insulated, were cyclically magnetized and demagnetized at room temperature by 1 T permanent magnets in order to induce an adiabatic magnetic effect. Under the experimental conditions tested, results showed a maximun non-accumulative temperature variation of 0.2 °C, insufficient to carry out an effective hypothermia. This study allowed us to discuss about the use of new materials and strategies for further in vivo experiments.
- MeSH
- biokompatibilní materiály MeSH
- cévní mozková příhoda terapie MeSH
- gadolinium MeSH
- magnetické pole MeSH
- magnetismus metody přístrojové vybavení MeSH
- techniky in vitro MeSH
- tepelná vodivost MeSH
- terapeutická hypotermie * metody přístrojové vybavení MeSH
- Publikační typ
- práce podpořená grantem MeSH
The aim of the present study is to develop new magnetic polymer microspheres with functional groups available for easy protein and antibody binding. Monodisperse macroporous poly(2-hydroxyethyl methacrylate) (PHEMA-COOH) microspheres ~4 µm in diameter and containing ∼1 mmol COOH/g were synthesized by multistep swelling polymerization of 2-hydroxyethyl methacrylate (HEMA), ethylene dimethacrylate (EDMA), and 2-[(methoxycarbonyl)methoxy]ethyl methacrylate (MCMEMA), which was followed by MCMEMA hydrolysis. The microspheres were rendered magnetic by precipitation of iron oxide inside the pores, which made them easily separable in a magnetic field. Properties of the resulting magnetic poly(2-hydroxyethyl methacrylate) (mgt.PHEMA) particles with COOH functionality were examined by scanning and transmission electron microscopy (SEM and TEM), static volumetric adsorption of helium and nitrogen, mercury porosimetry, Fourier transform infrared (FTIR) and atomic absorption spectroscopy (AAS), and elemental analysis. Mgt.PHEMA microspheres were coupled with p46/Myo1C protein purified from blood serum of multiple sclerosis (MS) patients, which enabled easy isolation of monospecific anti-p46/Myo1C immunoglobulin G (IgG) antibodies from crude antibody preparations of mouse blood serum. High efficiency of this approach was confirmed by SDS/PAGE, Western blot, and dot blot analyses. The newly developed mgt.PHEMA microspheres conjugated with a potential disease biomarker, p46/Myo1C protein, are thus a promising tool for affinity purification of antibodies, which can improve diagnosis and treatment of MS patients.
- MeSH
- imobilizované proteiny chemie imunologie MeSH
- imunoglobulin G imunologie izolace a purifikace MeSH
- lidé MeSH
- magnetismus metody MeSH
- magnety chemie MeSH
- mikrosféry MeSH
- myosin typu I chemie imunologie MeSH
- myši MeSH
- polyhydroxyethylmethakrylát chemie MeSH
- protein - isoformy chemie imunologie MeSH
- roztroušená skleróza diagnóza imunologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Previously reported DNA aptamers developed against surface proteins extracted from Campylobacter jejuni were further characterized by aptamer-based Western blotting and shown to bind epitopes on proteins weighing ~16 and 60 kD from reduced C. jejuni and Campylobacter coli lysates. Proteins of these approximate weights have also been identified in traditional antibody-based Western blots of Campylobacter spp. Specificity of the capture and reporter aptamers from the previous report was further validated by aptamer-based ELISA-like (ELASA) colorimetric microplate assay. Finally, the limit of detection of the previously reported plastic-adherent aptamer-magnetic bead and aptamer-quantum dot sandwich assay (PASA) was validated by an independent food safety testing laboratory to lie between 5 and 10 C. jejuni cells per milliliter in phosphate buffered saline and repeatedly frozen and thawed chicken rinsate. Such ultrasensitive and rapid (30 min) aptamer-based assays could provide alternative or additional screening tools to enhance food safety testing for Campylobacter and other foodborne pathogens.
- MeSH
- aptamery nukleotidové genetika MeSH
- biotest přístrojové vybavení metody MeSH
- Campylobacter genetika izolace a purifikace MeSH
- kontaminace potravin analýza MeSH
- kur domácí MeSH
- kvantové tečky chemie MeSH
- magnetismus metody MeSH
- maso mikrobiologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- validační studie MeSH
Magnetic isolation of biological targets is in major demand in the biotechnology industry today. This study considers the interaction of four surface-modified magnetic micro- and nanoparticles with selected DNA fragments. Different surface modifications of nanomaghemite precursors were investigated: MAN37 (silica-coated), MAN127 (polyvinylpyrrolidone-coated), MAN158 (phosphate-coated), and MAN164 (tripolyphosphate-coated). All particles were positive polycharged agglomerated monodispersed systems. Mean particle sizes were 0.48, 2.97, 2.93, and 3.67 μm for MAN37, MAN127, MAN164, and MAN158, respectively. DNA fragments exhibited negative zeta potential of -0.22 mV under binding conditions (high ionic strength, low pH, and dehydration). A decrease in zeta potential of particles upon exposure to DNA was observed with exception of MAN158 particles. The measured particle size of MAN164 particles increased by nearly twofold upon exposure to DNA. Quantitative PCR isolation of DNA with a high retrieval rate was observed by magnetic particles MAN127 and MAN164. Interaction between polycharged magnetic particles and DNA is mediated by various binding mechanisms such as hydrophobic and electrostatic interactions. Future development of DNA isolation technology requires an understanding of the physical and biochemical conditions of this process.
Magnetically modified yeast cells represent an interesting type of biocomposite material, applicable in various areas of bioanalysis, biotechnology and environmental technology. In this review, typical examples of magnetic modifications of yeast cells of the genera Saccharomyces, Kluyveromyces, Rhodotorula and Yarrowia are presented, as well as their possible applications as biocatalysts, active part of biosensors and biosorbents for the separation of organic xenobiotics, heavy metal ions and radionuclides.
- MeSH
- biodegradace MeSH
- biotechnologie metody MeSH
- kvasinky chemie metabolismus MeSH
- magnetismus metody MeSH
- těžké kovy MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
An extremely simple procedure has been developed for the immobilization of Saccharomyces cerevisiae cells on magnetic chitosan microparticles. The magnetic carrier was prepared using an inexpensive, simple, rapid, one-pot process, based on the microwave irradiation of chitosan and ferrous sulphate at high pH. Immobilized yeast cells have been used for sucrose hydrolysis, hydrogen peroxide decomposition and the adsorption of selected dyes.
- MeSH
- barvicí látky metabolismus MeSH
- biodegradace MeSH
- chitosan chemická syntéza chemie MeSH
- imobilizované buňky chemie metabolismus MeSH
- koncentrace vodíkových iontů MeSH
- magnetické jevy MeSH
- magnetismus metody MeSH
- mikrovlny MeSH
- peroxid vodíku metabolismus MeSH
- Saccharomyces cerevisiae chemie metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
Pigs represent an important source of food in many countries, and undercooked pork containing tissue cysts is one of the most common sources of Toxoplasma gondii infection for humans. A magnetic capture method for the isolation of T. gondii DNA and quantitative real-time PCR targeting the 529 bp TOXO repeat element were used to estimate the parasite burden in different tissues of pigs experimentally infected with T. gondii oocysts, and to determine the predilection sites of T. gondii in this host species. The highest concentration of T. gondii DNA was found in brain tissues, equivalent to [median] 553.7 (range 3857.7-121.9) parasites per gram, followed by lungs, heart and dorsal muscles with median values corresponding to 0.3 (range 61.3-0.02); 2.6 (range 7.34-0.37) and 0.6 (range 2.81-0.31) parasites per gram of tissue, respectively. Skeletal muscles from fore and hindlimb, liver and kidney presented very low infection burdens equivalent to [median] ≤0.2 parasites per gram of tissues, and no parasite DNA could be detected in the spleen. This study contributes to understanding the value of different pig tissues as a source of T. gondii infection for humans and shows that the brain, while not being of major importance as human food source, may represent a first-line selection tissue when performing non-serological surveys (e.g. bioassays, histopathological, immunohistochemical or molecular studies) to detect T. gondii infections in pigs.
- MeSH
- kvantitativní polymerázová řetězová reakce metody MeSH
- magnetismus metody MeSH
- mozek parazitologie patologie MeSH
- nemoci prasat parazitologie patologie MeSH
- prasata MeSH
- Toxoplasma chemie genetika izolace a purifikace fyziologie MeSH
- toxoplazmóza zvířat parazitologie patologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
