Characterization of histone post-translational modifications (PTMs) is still challenging, and robust histone sample preparation is essential for convincing evaluation of PTMs by mass spectrometry. An effective protocol for extracting plant histone proteins must also avoid excessive co-extraction of the numerous potential interfering compounds, including those related to secondary metabolism. Currently, the co-existence of histone marks is addressed mostly by shotgun proteomic analysis following chemical derivatization of histone lysine residues. Here, we report a straightforward approach for plant histone sample preparation for mass spectrometry, based on filter-aided sample preparation coupled with histone propionylation. The approach offers savings in sample handling and preparation time, enables removal of interfering compounds from the sample, and does not require either precipitation or dialysis of histone extract. We show the comparison of two protocol variants for derivatization of histone proteins, in-solution propionylation in the vial and propionylation on the filter unit. For both protocols, we obtained identical abundances of post-translationally modified histone peptides. Although shorter time is required for histone protein labeling on the filter unit, in-solution derivatization slightly outweighed filter-based variant by lower data variability. Nevertheless, both protocol variants appear to be efficient and convenient approach for preparation of plant histones for mass spectrometric analysis.

• Klíčová slova
• Arabidopsis thaliana, epigenetics, filter-aided sample preparation, histone derivatization, mass spectrometry, post-translational modifications,
• Publikační typ
• časopisecké články MeSH

A study of complex protein mixtures obtained from biological samples by MS demands proper purification and separation technique. The method of divergent flow isoelectric focusing (DF IEF) promises improvement of sample preparation in proteomic studies. DF IEF was carried out in a separation channel with increasing width. The channel was cut out from a polyester nonwoven web. DC voltage (800 V) was brought to two pairs of electrodes situated on the channel sides. Amphoteric compounds, including proteins, drift through the channel carried by flow (18-25 ml/h) in streamlines given by their isoelectric points. The pH gradient (3-10) and its stability during analysis have been monitored with colored low-molecular mass pI markers. Separated fractions were collected in ten microvials and further analyzed by MS. The suggested method was used for separation and purification of crude protein extract from barley grain, malt, and beer. Collected fractions of separated proteins were characterized by MALDI-MS. Desalting during IEF enhanced significantly the quality of mass spectra. It also simplified monitoring of post-translational modifications and protein changes occurring during malting and brewing. Results have shown the real potential of the suggested DF IEF device lay-out as an efficient preparative tool for separation and purification of complex protein mixtures for further analyses.

• MeSH
• časové faktory MeSH
• design vybavení MeSH
• elektrody MeSH
• isoelektrická fokusace přístrojové vybavení   metody   MeSH
• koncentrace vodíkových iontů MeSH
• metody pro přípravu analytických vzorků metody   MeSH
• molekulová hmotnost MeSH
• proteiny analýza   MeSH
• proteomika MeSH
• reprodukovatelnost výsledků MeSH
• senzitivita a specificita MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice přístrojové vybavení   metody   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• proteiny MeSH

New screen-printed sensor with a boron-doped diamond working electrode (SP/BDDE) was fabricated using a large-area linear antenna microwave chemical deposition vapor system (LA-MWCVD) with a novel precursor composition. It combines the advantages of disposable printed sensors, such as tailored design, low cost, and easy mass production, with excellent electrochemical properties of BDDE, including a wide available potential window, low background currents, chemical resistance, and resistance to passivation. The newly prepared SP/BDDEs were characterized by scanning electron microscopy (SEM) and Raman spectroscopy. Their electrochemical properties were investigated by cyclic voltammetry and electrochemical impedance spectroscopy using inner sphere ([Fe(CN)6]4-/3-) and outer sphere ([Ru(NH3)6]2+/3+) redox probes. Moreover, the applicability of these new sensors was verified by analysis of the anti-inflammatory drug lornoxicam in model and pharmaceutical samples. Using optimized differential pulse voltammetry in Britton-Robinson buffer of pH 3, detection limits for lornoxicam were 9 × 10-8 mol L-1. The oxidation mechanism of lornoxicam was investigated using bulk electrolysis and online electrochemical cell with mass spectrometry; nine distinct reaction steps and corresponding products and intermediates were identified.

• Klíčová slova
• analytical application, boron-doped diamond electrode, characterization, electrochemical properties, lornoxicam, preparation, screen-printed sensor,
• MeSH
• bor * chemie   MeSH
• elektrody MeSH
• elektrolýza * MeSH
• oxidace-redukce MeSH
• Ramanova spektroskopie MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• bor * MeSH

The deposition of multilayer coating of NiTi is carried out by a thermal plasma spraying process on a stainless steel substrate. The deposition of melted NiTi particles creates an adhesion layer on the substrate with the subsequent formation of multilayer coating with a certain thickness. Six layers of coating are created to achieve a certain thickness in terms of the sprayed sample. This paper aims to investigate multilayer NiTi coatings created through a thermal plasma process. The key variable feed rate was considered, as well as its effect on the microstructure characteristics. The shape memory effect associated with the coating properties was analyzed in detail. The variable feed rate was considered one of the most important parameters in the thermal plasma spraying process due to its ability to control the quality and compactness of the coating structure. The coatings were characterized by examining their microstructure, thermal, chemical, and microhardness. The indent marks were made/realized along the cross-section surface for the analysis of crack propagation resistance and wear properties. The coating's surface did not display segmentation crack lines. Nevertheless, the cross-sectional surfaces showed evidence of crack lines. There were eutectic zones of the interlamellar structure observed in the structure of the coating. The plasma-sprayed samples from thermo-mechanical analysis of the hysteresis curve provide strong confirmation of the shape memory effect.

• Klíčová slova
• characterization, deposition, thermal plasma process, thick NiTi coating,
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Konjac glucomannan (KGM) has been widely applied in the food industry as a thickening and gelation agent because of its unique colloidal properties of viscosity enhancement and gelling ability. The current study aimed to prepare and characterize KGM and deacetylated KGM (Da-KGM) samples obtained by sonication in neutral and alkali ethanol-water solutions. RESULTS: The results showed that the deacetylation degree (DD) of Da-KGM increased exponentially with alkali concentration. Fourier transform infrared spectrometry further confirmed the deacetylation reaction through the dramatic decrease in the acetyl group band at 1740 cm-1 . Besides, the high similarity among the tested groups in terms of X-ray diffraction (XRD) spectra implied a similar crystalline structure, while differential scanning calorimetry (DSC) curves revealed that the water binding capacity and decomposition temperature of KGM changed slightly with alkali and sonication treatment. The rheological profiles indicated that apparent viscosity (η0 ) of sonicated KGM samples was unchanged except for the T60 group (60 min sonication treatment). Particularly, ultrasonic treatment under high alkaline conditions (0.10 mol L-1 NaOH) was noted to promote the deacetylation reaction, and the obtained samples showed decreased apparent viscosity and weakened the gelation process in aqueous solution. Partial correction analysis indicated that alkali rather than ultrasonic treatment resulted in the change of DD and η0 in Da-KGM. Moreover, sonication contributed to off-white color by reducing the browning caused by alkali in Da-KGM products. CONCLUSION: Ultrasound-mediated heterogeneous deacetylation reaction is a feasible way to prepare Da-KGM samples with lightened browning and controllable DD. © 2022 Society of Chemical Industry.

• Klíčová slova
• characterization, heterogeneous deacetylation, konjac glucomannan, rheological properties, ultrasonic treatment,
• MeSH
• alkálie MeSH
• mannany * chemie   MeSH
• vibrace ultrazvukové * MeSH
• voda chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• (1-6)-alpha-glucomannan MeSH Prohlížeč
• alkálie MeSH
• mannany * MeSH
• voda MeSH

This paper describes laboratory preparation, characterization and antibacterial activity testing of ZnO/kaoline composites. ZnO/kaoline composites with 50 wt.% of ZnO were laboratory prepared, dried at 105 °C and calcined at 500 °C. XRPD analysis revealed that thermal treatment caused the phase transformation of Zn containing precursor into ZnO. Scanning and transmission electron microscopy techniques were used for characterization of morphology of the prepared samples. A standard microdilution test was used for evaluation of antibacterial activity using four common human pathogens (Staphylococcus aureus, Escherichia coli, Enterococcus faecalis and Pseudomonas aeruginosa). Daylight was used for induction photocatalytically based antibacterial activity. Second possible explanation of antibacterial activity of ZnO/kaoline could be the presence of biologically available forms of zinc. During the antibacterial activity assays the ZnO/kaoline composites exhibited antibacterial activity, where differences in an onset of the antibacterial activity and activity against bacterial strains were observed. The highest antibacterial activity was observed against S. aureus, where the lowest value of minimum inhibitory concentration was determined equal to 0.41 mg/ml.

• MeSH
• antibakteriální látky chemie   farmakologie   MeSH
• difrakce rentgenového záření MeSH
• Enterococcus faecalis účinky léků   MeSH
• Escherichia coli účinky léků   MeSH
• kaolin chemie   MeSH
• katalýza MeSH
• nanokompozity chemie   ultrastruktura   MeSH
• oxid zinečnatý chemie   MeSH
• Pseudomonas aeruginosa účinky léků   MeSH
• Staphylococcus aureus účinky léků   MeSH
• světlo MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antibakteriální látky MeSH
• kaolin MeSH
• oxid zinečnatý MeSH

Time-resolved cryo electron microscopy (TRCEM) has emerged as a powerful technique for transient structural characterization of isolated biomacromolecular complexes in their native state within the time scale of seconds to milliseconds. For TRCEM sample preparation, microfluidic device [9] has been demonstrated to be a promising approach to facilitate TRCEM biological sample preparation. It is capable of achieving rapidly aqueous sample mixing, controlled reaction incubation, and sample deposition on electron microscopy (EM) grids for rapid freezing. One of the critical challenges is to transfer samples to cryo-EM grids from the microfluidic device. By using microspraying method, the generated droplet size needs to be controlled to facilitate the thin ice film formation on the grid surface for efficient data collection, while not too thin to be dried out before freezing, i.e., optimized mean droplet size needs to be achieved. In this work, we developed a novel monolithic three dimensional (3D) annular gas-assisted microfluidic sprayer using 3D MEMS (MicroElectroMechanical System) fabrication techniques. The microsprayer demonstrated dense and consistent microsprays with average droplet size between 6-9 μm, which fulfilled the above droplet size requirement for TRCEM sample preparation. With droplet density of around 12-18 per grid window (window size is 58×58 μm), and the data collectible thin ice region of >50% total wetted area, we collected ~800-1000 high quality CCD micrographs in a 6-8 hour period of continuous effort. This level of output is comparable to what were routinely achieved using cryo-grids prepared by conventional blotting and manual data collection. In this case, weeks of data collection process with the previous device [9] has shortened to a day or two. And hundreds of microliter of valuable sample consumption can be reduced to only a small fraction.

• Klíčová slova
• Microfluidics, cryo EM, microdroplet, micronozzle, microspray, monolithic device, time-resolved TEM,
• Publikační typ
• časopisecké články MeSH

Determination of an antihyperlipidemic drug simvastatin (SIM) was carried out using a carbon paste electrode bulk-modified with multiwalled carbon nanotubes (MWCNT-CPE). Scanning electrochemical microscopy (SECM), scanning electron microscopy (SEM), and atomic force microscopy (AFM) were used for the characterization of the prepared electrodes. Different electrodes were prepared varying in mass percentage of MWCNTs to find out the optimum amount of MWCNTs in the paste. The MWCNT-CPE in which the mass percentage of MWCNTs was 25% (w/w) was found as the optimum. Then, the prepared electrode was used in a mechanistic study and sensitive assay of SIM in pharmaceutical dosage form and a spiked human plasma sample using differential pulse voltammetry (DPV). The prepared electrode shows better sensitivity compared to the bare carbon paste and glassy carbon electrode (GCE). The detection limit and the limit of quantification were calculated to be 2.4 × 10-7 and 8 × 10-7, respectively. The reproducibility of the electrode was confirmed by the low value of the relative standard deviation (RSD% = 4.8%) when eight measurements of the same sample were carried out. Determination of SIM in pharmaceutical dosage form was successfully performed with a bias of 0.3% and relative recovery rate of 99.7%. Furthermore, the human plasma as a more complicated matrix was spiked with a known concentration of SIM and the spiking recovery rate was determined with the developed method to be 99.5%.

• Klíčová slova
• biological sample, carbon paste electrode, mechanism study, multiwalled carbon nanotube, scanning electrochemical microscopy, simvastatin determination,
• MeSH
• elektrody * MeSH
• lidé MeSH
• mikroskopie elektronová rastrovací MeSH
• nanotrubičky uhlíkové chemie   ultrastruktura   MeSH
• simvastatin chemie   MeSH
• uhlík chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• nanotrubičky uhlíkové MeSH
• simvastatin MeSH
• uhlík MeSH

Preparation of nanocomposite kaolinite/TiO(2), using hydrolysis of titanyl sulfate in the presence of kaolin was addressed. A variable (kaolin)/(titanyl sulfate) ratio has been used in order to achieve the desired TiO(2) content in prepared nanocomposites. Calcination of the composites at 600 °C led to the transformation of the kaolinite to metakaolinite and to origination of metakaolinite/TiO(2) composites. The prepared samples were investigated using X-ray fluorescence spectroscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetry and diffuse reflectance spectroscopy in the UV-VIS region. Structural ordering of TiO(2) on the kaolinite particle surface was modeled using empirical force field atomistic simulations in the Material Studio modeling environment. Photodegradation activity of the composites prepared was evaluated by the discoloration of Acid Orange 7 aqueous solution.

• MeSH
• azosloučeniny chemie   účinky záření   MeSH
• barvicí látky chemie   účinky záření   MeSH
• benzensulfonáty chemie   účinky záření   MeSH
• fotolýza * MeSH
• kaolin chemie   MeSH
• látky znečišťující životní prostředí chemie   účinky záření   MeSH
• nanokompozity chemie   MeSH
• počítačová simulace MeSH
• povrchové vlastnosti MeSH
• průmyslový odpad prevence a kontrola   MeSH
• titan chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 2-naphthol orange MeSH Prohlížeč
• azosloučeniny MeSH
• barvicí látky MeSH
• benzensulfonáty MeSH
• kaolin MeSH
• látky znečišťující životní prostředí MeSH
• průmyslový odpad MeSH
• titan MeSH
• titanium dioxide MeSH Prohlížeč

This study aimed to prepare a bioactive acrylic material by adding different types of glasses. Commercially available polymerized acrylic resin was mixed with 10% of four different types of glasses in the powder form and cured. Flexural strength, sorption, and solubility of the samples were tested according to ISO 20795-1:2013. The total number of samples used in the tests were 60. The materials were placed in artificial saliva of pH 4 and 7, and elution was performed for 0, 1, 28, and 42 days. The collected samples were analyzed using inductively coupled plasma atomic emission spectrometry to detect Ca, P, and Si ions and using ion chromatography to detect F ions. The materials obtained after modification with glasses showed lower compressive strength compared with pure polymethyl methacrylate but met the standard requirements. Two glass types showed higher solubility values compared with the value defined by the ISO standard. Biomin C and S53P4 released Ca, P, and Si ions, respectively, after 42 days in artificial saliva. Acrylic resins modified with 10% Biomin C and S53P4 glasses can be a valuable source of Ca and P ions under acid conditions for 28 and 42 days.

• MeSH
• akrylové pryskyřice * chemie   MeSH
• náhrada slin MeSH
• polymethylmethakrylát * chemie   MeSH
• prášky, zásypy, pudry MeSH
• testování materiálů MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• akrylové pryskyřice * MeSH
• náhrada slin MeSH
• polymethylmethakrylát * MeSH
• prášky, zásypy, pudry MeSH