The black market for new psychoactive substances has been constantly evolving and the substances that appear on this market cause a considerable number of issues, in extreme cases leading to human deaths. While monitoring the drug black market, we detected a sample of a dissociative anesthetic methoxphenidine, the salt of which contained an unusual anion in the form of bromo- and chloro-zincate complex. Concerning the unknown and potentially hazardous properties of this sample, we performed an in vitro cytotoxicity screening in cell lines of various origins (e.g., kidney, liver, bladder) which was compared with the toxicity results of the methoxphenidine standard prepared for this purpose. The street methoxphenidine sample exhibited markedly higher toxicity than the standard, which was probably caused by the anion impurity. Since it is not usual to analyze anions in salts of novel psychoactive substances, but such samples may be commonly available at the drug black market, we have developed a method for their identification with X-ray powder diffraction (XRPD), which also enabled us to distinguish between different polymorphs/solvates of methoxphenidine that were crystallized in the laboratory. XRPD offers additional data about samples, which may not be discovered by routine techniques, and in some cases, they may help to find out essential information.
In this study, a simple and green strategy was reported to prepare bimetallic nanoparticles (NPs) by the combination of zinc oxide (ZnO) and copper oxide (CuO) using Sambucus nigra L. extract. The physicochemical properties of these NPs such as crystal structure, size, and morphology were studied by X-ray diffraction (XRD), field emission gun scanning electron microscopy (FEG-SEM), and transmission electron microscopy (TEM). The results suggested that these NPs contained polygonal ZnO NPs with hexagonal phase and spherical CuO NPs with monoclinic phase. The anticancer activity of the prepared bimetallic NPs was evaluated against lung and human melanoma cell lines based on MTT assay. As a result, the bimetallic ZnO/CuO NPs exhibited high toxicity on melanoma cancer cells while their toxicity on lung cancer cells was low.
- MeSH
- antibakteriální látky chemie farmakologie MeSH
- bez černý chemie MeSH
- buňky A549 MeSH
- cytotoxiny chemie farmakologie MeSH
- difrakce rentgenového záření metody MeSH
- kovové nanočástice chemie MeSH
- lidé MeSH
- listy rostlin chemie MeSH
- měď chemie farmakologie MeSH
- mikrobiální testy citlivosti metody MeSH
- nádorové buněčné linie MeSH
- oxid zinečnatý chemie farmakologie MeSH
- rostlinné extrakty chemie farmakologie MeSH
- spektroskopie infračervená s Fourierovou transformací metody MeSH
- technologie zelené chemie metody MeSH
- transmisní elektronová mikroskopie metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
We present a computational case study of X-ray single-particle imaging of hydrated proteins on an example of 2-Nitrogenase-Iron protein covered with water layers of various thickness, using a start-to-end simulation platform and experimental parameters of the SPB/SFX instrument at the European X-ray Free-Electron Laser facility. The simulations identify an optimal thickness of the water layer at which the effective resolution for imaging the hydrated sample becomes significantly higher than for the non-hydrated sample. This effect is lost when the water layer becomes too thick. Even though the detailed results presented pertain to the specific sample studied, the trends which we identify should also hold in a general case. We expect these findings will guide future single-particle imaging experiments using hydrated proteins.
- MeSH
- difrakce rentgenového záření přístrojové vybavení metody MeSH
- elektrony MeSH
- fotony MeSH
- lasery * MeSH
- molekulární zobrazování metody MeSH
- oxidoreduktasy chemie účinky záření MeSH
- rentgenové záření škodlivé účinky MeSH
- simulace molekulární dynamiky * MeSH
- voda chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Current studies reveal that the biomineralization of U(VI) by anaerobes normally produces nano-sized U(IV) minerals that can easily re-migrate/re-oxidize, while the biomineralization of U(VI) by aerobes has been constrained because the general mechanism has not yet been fully characterized. The biomineralization of U(VI) by Bacillus cereus 12-2 was investigated in this work. The maximum biosorption capability of intact cells was 448.68 mg U/g biomass (dry weight) at pH 5, while a decrease over 60% was induced when phosphate, amino, and especially carboxyl groups were shielded. X-ray diffraction, electron microscopy, and tracing the concentration of soluble intracellular U(VI) demonstrated that extracellular amorphous uranium particles can directly enter cells as solid, and about 10 nm-sized (NH4)(UO2)PO4·3H2O was formed subsequently. It was also revealed that the biosorption capability was not affected by a high uranium concentration, while biomineralization was inhibited, suggesting that a high concentration of heavy metals may inhibit the enzyme activity involved in biomineralization. Besides, U(VI) could trigger the overexpression of proteins with a molecular weight of 22 kD, including various phosphatases, kinases, and other enzymes that are related to metabolism and stimulus response, which may contribute to the intracellular transformation of U(VI) compounds from amorphous to crystalline phase. Taken together, the immobilization of U(VI) by B. cereus 12-2 contains two major steps: (1) fast immobilization of U(VI) on the cell surface as amorphous compounds, in which the carboxyl groups served as the predominant coordination functional groups and (2) transport of amorphous particles to cells directly and enzyme-related formation of uramphite.
- MeSH
- Bacillus cereus chemie MeSH
- difrakce rentgenového záření metody MeSH
- minerály chemie MeSH
- uran chemie MeSH
- Publikační typ
- časopisecké články MeSH
Human aldo-keto reductase 1C3 (AKR1C3) stereospecifically reduces steroids and prostaglandins and is involved in the biotransformation of xenobiotics. Its role in various cancers makes it a potential therapeutic target for the development of inhibitors. Recombinant AKR1C3 with a thrombin-cleavable N-terminal His6 tag was expressed from a pET-28(+) vector for structural studies of enzyme-inhibitor complexes. A modified in situ proteolysis approach was applied to specifically remove the His tag by thrombin cleavage during crystallization screening trials. This improved the morphology and diffraction quality of the crystals and allowed the acquisition of high-resolution diffraction data and structure solution. This approach may be generally applicable to other proteins expressed using the pET-28(+) vector.
- MeSH
- difrakce rentgenového záření metody MeSH
- histidin * genetika MeSH
- krystalizace metody MeSH
- krystalografie rentgenová metody MeSH
- lidé MeSH
- protein AKR1C3 chemie genetika metabolismus MeSH
- proteolýza MeSH
- sekvence aminokyselin MeSH
- thrombin metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Herein we describe a novel alternative synthesis route of polyvinylpyrrolidone nanoparticles using salting-out method at a temperature close to polyvinylpyrrolidone decomposition. At elevated temperatures, the stability of polyvinylpyrrolidone decreases and the opening of pyrrolidone ring fractions occurs. This leads to cross-linking process, where separate units of polyvinylpyrrolidone interact among themselves and rearrange to form nanoparticles. The formation/stability of these nanoparticles was confirmed by transmission electron microscopy, X-ray photoelectron spectroscopy, mass spectrometry, infrared spectroscopy, and spectrophotometry. The obtained nanoparticles possess exceptional biocompatibility. No toxicity and genotoxicity was found in normal human prostate epithelium cells (PNT1A) together with their high hemocompatibility. The antimicrobial effects of polyvinylpyrrolidone nanoparticles were tested on bacterial strains isolated from the wounds of patients suffering from hard-to-heal infections. Molecular analysis (qPCR) confirmed that the treatment can induce the regulation of stress-related survival genes. Our results strongly suggest that the polyvinylpyrrolidone nanoparticles have great potential to be developed into a novel antibacterial compound.
- MeSH
- antibakteriální látky chemie farmakologie MeSH
- biokompatibilní materiály chemie farmakologie MeSH
- buněčné linie MeSH
- difrakce rentgenového záření metody MeSH
- epitel účinky léků MeSH
- fotoelektronová spektroskopie metody MeSH
- lidé MeSH
- mikrobiální testy citlivosti metody MeSH
- nanočástice chemie MeSH
- povidon chemie MeSH
- prostata účinky léků MeSH
- spektroskopie infračervená s Fourierovou transformací metody MeSH
- stabilita léku MeSH
- transmisní elektronová mikroskopie metody MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Tenofovir disoproxil fumarate (TDF, form I) is an orally delivered pharmaceutical salt used for the treatment of HIV and chronic hepatitis, which acts as an inhibitor of nucleotide reverse transcriptase. There are many solid forms of TDF described in the literature; 2 of them were identified in the drug products: form I and form A. It seems that during formulation, the active pharmaceutical ingredient undergoes partial to total conversion of TDF form I to TDF form A. The goals of this study were to investigate when and why did the conversion occur and whether the conversion could be avoided and how. The influence of pH and possible interaction with excipients were studied. The conditions enabling using wet granulation in technology while preventing the undesired conversion were found. The stabilization was achieved either by replacement of used disintegrants or by acid addition to the current composition of formulation.
- MeSH
- difrakce rentgenového záření metody MeSH
- koncentrace vodíkových iontů MeSH
- látky proti HIV chemie metabolismus MeSH
- pomocné látky chemie metabolismus MeSH
- příprava léků metody MeSH
- stabilita léku MeSH
- tenofovir chemie metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
This paper deals with an investigation of ceramic archaeological finds with the use of in-situ X-ray fluorescence analysis. Firstly, three configurations of X-ray fluorescence analyzers constructed and used at the Czech Technical University in Prague are described and compared for use in a non-destructive survey of siliceous materials. Detection limits, depth of analysis, the relation of the analyzed area, the homogeneity of the samples, and variations in the element concentrations are discussed. Secondly, many shards of postmediaeval pottery from Southern Moravia are analyzed with X-ray fluorescence analysis and some of them also with electron microprobe analysis. Selected results are described.
- MeSH
- barvicí látky analýza MeSH
- dějiny středověku MeSH
- difrakce rentgenového záření metody MeSH
- keramika analýza MeSH
- rukopisy jako téma dějiny MeSH
- sochařství dějiny MeSH
- spektrometrie rentgenová emisní metody MeSH
- Check Tag
- dějiny středověku MeSH
- Publikační typ
- časopisecké články MeSH
- historické články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
In this work we present the application of X-ray fluorescence analysis (XRFA) in an investigation of the Land Register and the Register of the Court of the Kingdom of Bohemia and the manuscript of the Homiliary of the Opatovice Monastery from the 12th century. Radionuclide sources emitting radiation at an appropriate energy level and an X-ray tube were used to excite the characteristic radiation. A spectrometric Si(Li) detector and a Si-PIN detector with Peltier cooling were used to detect the excited characteristic radiation. Several types of pigments were identified and compositions of inks used within almost 5 centuries in the offices at the Prague Castle were determined.
- MeSH
- barvicí látky analýza MeSH
- dějiny středověku MeSH
- difrakce rentgenového záření metody MeSH
- rukopisy jako téma dějiny MeSH
- Check Tag
- dějiny středověku MeSH
- Publikační typ
- časopisecké články MeSH
- historické články MeSH
- Geografické názvy
- Česká republika MeSH
X-ray fluorescence analysis with an evaluation of the Kalpha/Kbeta or Lalpha/Lbeta count rate ratios enables a layered structure to be recognized, because the measured ratio of two lines of one element depends on the depth distribution of this element in the analyzed objects. Several specimens consisting of layers of various pigments were analyzed to demonstrate the possibilities of the proposed technique. Then the Lalpha/Lbeta technique was applied in an investigation of cinnabar distribution in mediaeval manuscripts.
