This study explores the structural and electronic factors affecting the absorption spectra of 5-carboxy-tetramethylrhodamine (TAMRA) in water, a widely used fluorophore in imaging and molecular labeling in biophysical studies. Through molecular dynamics (MD) simulations and density functional theory (DFT) calculations, we examine TAMRA UV absorption spectra together with TAMRA-labeled peptides (Arg9, Arg4, Lys9). We found that DFT calculations with different functionals underestimate TAMRA maximum UV absorption peak by ~100 nm, resulting in the maximum at ca. 450 nm instead of the experimental value of ca. 550 nm. However, incorporating MD simulation snapshots of TAMRA in water, the UV maximum peak shifts and is in close agreement with the experimental results due to the rotation of TAMRA N(CH3)2 groups, effectively captured in MD simulations. The method is used to estimate the UV absorption spectra of TAMRA-labeled peptides, matching experimental values.

• Klíčová slova
• UV absorption spectra, fluorescent probes, molecular dynamics simulations, time‐dependent density functional theory,
• MeSH
• fluorescenční barviva chemie   MeSH
• peptidy * chemie   MeSH
• rhodaminy * chemie   MeSH
• simulace molekulární dynamiky * MeSH
• spektrofotometrie ultrafialová MeSH
• teorie funkcionálu hustoty * MeSH
• voda chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 5-carboxytetramethylrhodamine succinimidyl ester MeSH Prohlížeč
• fluorescenční barviva MeSH
• peptidy * MeSH
• rhodaminy * MeSH
• voda MeSH

Changes in the protonation state of lyophilized proteins can impact structural integrity, chemical stability, and propensity to aggregate upon reconstitution. When a buffer is chosen, the freezing/drying process may result in dramatic changes in the protonation state of the protein due to ionization shift of the buffer. In order to determine whether protonation shifts are occurring, ionizable probes can be added to the formulation. Optical probes (dyes) have shown dramatic ionization changes in lyophilized products, but it is unclear whether the pH indicator is uniform throughout the matrix and whether the change in the pH indicator actually mirrors drug ionization changes. In solid-state NMR (SSNMR) spectroscopy, the chemical shift of the carbonyl carbon in carboxylic acids is very sensitive to the ionization state of the acid. Therefore, SSNMR can be used to measure ionization changes in a lyophilized matrix by employing a small quantity of an isotopically-labeled carboxylic acid species in the formulation. This paper compares the apparent pH of six trehalose-containing lyophilized buffer systems using SSNMR and UV-Vis diffuse reflectance spectroscopy (UVDRS). Both SSNMR and UVDRS results using two different ionization probes (butyric acid and bromocresol purple, respectively) showed little change in apparent acidity compared to the pre-lyophilized solution in a sodium citrate buffer, but a greater change was observed in potassium phosphate, sodium phosphate, and histidine buffers. While the trends between the two methods were similar, there were differences in the numerical values of equivalent pH (pHeq) observed between the two methods. The potential causes contributing to the differences are discussed.

• Klíčová slova
• Diffuse reflectance spectroscopy, Lyophilization, Solid-state NMR spectroscopy, Solid-state acidity, UV/VIS,
• MeSH
• fosfáty * chemie   MeSH
• histidin * chemie   MeSH
• koncentrace vodíkových iontů MeSH
• kyselina citronová chemie   MeSH
• lyofilizace * metody   MeSH
• magnetická rezonanční spektroskopie * metody   MeSH
• pufry MeSH
• spektrofotometrie ultrafialová metody   MeSH
• trehalosa * chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• fosfáty * MeSH
• histidin * MeSH
• kyselina citronová MeSH
• pufry MeSH
• trehalosa * MeSH

Oleaginous filamentous fungi can accumulate large amount of cellular lipids and biopolymers and pigments and potentially serve as a major source of biochemicals for food, feed, chemical, pharmaceutical, and transport industries. We assessed suitability of Fourier transform (FT) Raman spectroscopy for screening and process monitoring of filamentous fungi in biotechnology. Six Mucoromycota strains were cultivated in microbioreactors under six growth conditions (three phosphate concentrations in the presence and absence of calcium). FT-Raman and FT-infrared (FTIR) spectroscopic data was assessed in respect to reference analyses of lipids, phosphorus, and carotenoids by using principal component analysis (PCA), multiblock or consensus PCA, partial least square regression (PLSR), and analysis of spectral variation due to different design factors by an ANOVA model. All main chemical biomass constituents were detected by FT-Raman spectroscopy, including lipids, proteins, cell wall carbohydrates, and polyphosphates, and carotenoids. FT-Raman spectra clearly show the effect of growth conditions on fungal biomass. PLSR models with high coefficients of determination (0.83-0.94) and low error (approximately 8%) for quantitative determination of total lipids, phosphates, and carotenoids were established. FT-Raman spectroscopy showed great potential for chemical analysis of biomass of oleaginous filamentous fungi. The study demonstrates that FT-Raman and FTIR spectroscopies provide complementary information on main fungal biomass constituents.

• Klíčová slova
• biodiesel, biopolymers, carotenoids, chitin, chitosan, fatty acids, fermentation, fungi, oleaginous microorganisms, pigments,
• MeSH
• analýza hlavních komponent MeSH
• biologické pigmenty analýza   MeSH
• biomasa MeSH
• biotechnologie MeSH
• chromatografie plynová MeSH
• fosfor analýza   metabolismus   MeSH
• Fourierova analýza MeSH
• houby chemie   růst a vývoj   MeSH
• karotenoidy analýza   MeSH
• lipidy analýza   MeSH
• magnetická rezonanční spektroskopie MeSH
• Ramanova spektroskopie metody   MeSH
• spektrofotometrie ultrafialová MeSH
• spektroskopie infračervená s Fourierovou transformací MeSH
• vápník metabolismus   MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• biologické pigmenty MeSH
• fosfor MeSH
• karotenoidy MeSH
• lipidy MeSH
• vápník MeSH

Novel photoactive and enzymatically active nanomotors were developed for efficient organic pollutant degradation. The developed preparation route is simple and scalable. Light-absorbing polypyrrole nanoparticles were equipped with a bi-enzyme [glucose oxidase/catalase (GOx/Cat)] system enabling the simultaneous utilization of light and glucose as energy sources for jet-induced nanoparticle movement and active radical production. The GOx utilizes glucose to produce hydrogen peroxide, which is subsequently degraded by Cat, resulting in the generation of active radicals and/or oxygen bubbles that propel the particles. Uneven grafting of GOx/Cat molecules on the nanoparticle surface ensures inhomogeneity of peroxide creation/degradation, providing the nanomotor random propelling. The nanomotors were tested for their ability to degrade chlorophenol, under various experimental conditions, that is, with and without simulated sunlight illumination or glucose addition. In all cases, degradation was accelerated by the presence of the self-propelled nanoparticles or light illumination. Light-induced heating also positively affects enzymatic activity, further accelerating nanomotor diffusion and pollutant degradation. In fact, the chemical and photoactivities of the nanoparticles led to more than 95% removal of chlorophenol in 1 h, without any external stirring. Finally, the quality of the purified water and the extent of pollutant removal were checked using an eco-toxicological assay, with demonstrated significant synergy between glucose pumping and sunlight illumination.

• Klíčová slova
• cascade enzyme nanomotors, chlorophenol, glucose, pollutant degradation, polypyrrole nanoparticles, sunlight,
• MeSH
• chemické látky znečišťující vodu chemie   MeSH
• glukosa chemie   MeSH
• mikroskopie elektronová rastrovací MeSH
• polymery chemie   MeSH
• pyrroly chemie   MeSH
• robotika * MeSH
• sluneční záření * MeSH
• spektrofotometrie ultrafialová metody   MeSH
• transmisní elektronová mikroskopie MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chemické látky znečišťující vodu MeSH
• glukosa MeSH
• polymery MeSH
• polypyrrole MeSH Prohlížeč
• pyrroly MeSH

The alkaline milieu of chronic wounds severely impairs the therapeutic effect of antibiotics, such as rifampicin; as such, the development of new drugs, or the smart delivery of existing drugs, is required. Herein, two innovative polyelectrolyte nanoparticles (PENs), composed of an amphiphilic chitosan core and a polycationic shell, were synthesized at alkaline pH, and in vitro performances were assessed by 1H NMR, elemental analysis, FT-IR, XRD, DSC, DLS, SEM, TEM, UV/Vis spectrophotometry, and HPLC. According to the results, the nanostructures exhibited different morphologies but similar physicochemical properties and release profiles. It was also hypothesized that the simultaneous use of the nanosystem and an antioxidant could be therapeutically beneficial. Therefore, the simultaneous effects of ascorbic acid and PENs were evaluated on the release profile and degradation of rifampicin, in which the results confirmed their synergistic protective effect at pH 8.5, as opposed to pH 7.4. Overall, this study highlighted the benefits of nanoparticulate development in the presence of antioxidants, at alkaline pH, as an efficient approach for decreasing rifampicin degradation.

• Klíčová slova
• alkaline pH, ascorbic acid, polyelectrolyte nanoparticles, rifampicin,
• MeSH
• diferenciální skenovací kalorimetrie MeSH
• difrakce rentgenového záření MeSH
• koncentrace vodíkových iontů MeSH
• lékové transportní systémy * MeSH
• nanočástice chemie   ultrastruktura   MeSH
• polyelektrolyty chemie   MeSH
• protonová magnetická rezonanční spektroskopie MeSH
• rifampin farmakologie   MeSH
• síran dextranu chemie   MeSH
• spektrofotometrie ultrafialová MeSH
• spektroskopie infračervená s Fourierovou transformací MeSH
• statická elektřina MeSH
• uvolňování léčiv MeSH
• velikost částic MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• polyelektrolyty MeSH
• rifampin MeSH
• síran dextranu MeSH

The biological electron transfer reactions play an important role in the bioactivity of drugs; thus, the knowledge of their electrochemical behavior is crucial. The formation of radicals during oxidation or reduction, the presence of short-living intermediates, the determination of reaction mechanisms involving electron and proton transfers, all contribute to the comprehension of drug activities and the determination of their mode of action and their metabolites. In addition, if a drug is encapsulated in the cyclodextrin cavity, its electrochemical properties can change compared to a free drug molecule. Here we describe the combination of cyclic voltammetry, UV-Vis spectroelectrochemistry, GC-MS, HPLC-DAD, and HPLC-MS/MS as techniques for evaluating the oxidation mechanism of a drug encapsulated in the cavity of a cyclodextrin. The cavity of cyclodextrin plays a significant role in increasing the stability of the encapsulated products; therefore the identification of oxidation intermediates as semiquinone and benzofuranone derivatives of quercetin is possible in these conditions. The differences in oxidation potentials of the bioactive flavonol quercetin and its cyclodextrin complex relating to its antioxidant activity and the oxidation mechanism are herein discussed.

• Klíčová slova
• Chromatography, Cyclic voltammetry, Drug oxidation, Drug–cyclodextrin complex, Electron transfer, Mass spectrometry, Oxidation mechanism, Spectroelectrochemistry, Stability of intermediates,
• MeSH
• antioxidancia chemie   MeSH
• cyklodextriny chemie   MeSH
• elektrochemické techniky * MeSH
• nosiče léků chemie   MeSH
• quercetin chemie   MeSH
• spektrofotometrie ultrafialová MeSH
• tandemová hmotnostní spektrometrie MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antioxidancia MeSH
• cyklodextriny MeSH
• nosiče léků MeSH
• quercetin MeSH

Capillary electrophoresis represents a promising technique in the field of pharmaceutical analysis. The presented review provides a summary of capillary electrophoretic methods suitable for routine quality control analyses of small molecule drugs published since 2015. In total, more than 80 discussed methods are sorted into three main sections according to the applied electroseparation modes (capillary zone electrophoresis, electrokinetic chromatography, and micellar, microemulsion, and liposome-electrokinetic chromatography) and further subsections according to the applied detection techniques (UV, capacitively coupled contactless conductivity detection, and mass spectrometry). Key parameters of the procedures are summarized in four concise tables. The presented applications cover analyses of active pharmaceutical ingredients and their related substances such as degradation products or enantiomeric impurities. The contribution of reported results to the current knowledge of separation science and general aspects of the practical applications of capillary electrophoretic methods are also discussed.

• Klíčová slova
• Capillary electrophoresis, Drug degradation, Drug impurity, Electrokinetic chromatography, Enantioseparation,
• MeSH
• elektroforéza kapilární metody   MeSH
• hmotnostní spektrometrie MeSH
• léčivé přípravky * analýza   normy   MeSH
• řízení kvality MeSH
• spektrofotometrie ultrafialová MeSH
• stereoizomerie MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• léčivé přípravky * MeSH

The dark web scene has been drawing the attention of law enforcement agencies and researchers alike. To date, most of the published works on the dark web are based on data gained by passive observation. To gain a more contextualized perspective, a study was conducted in which three vendors were selected on the "Dream Market" dark web marketplace, from whom subsequently several new psychoactive substances (NPS) were ordered. All transactions were documented from the initial drug deal solicitation to the final qualitative analysis of all received samples. From the selected vendors, a total of nine NPS samples was obtained, all of which were analyzed by NMR, HRMS, LC-UV, and two also by x-ray diffraction. According to our analyses, four of the five substances offered under already known NPS names contained a different NPS. The selected vendors therefore either did not know about their product, or deliberately deceived the buyers. Furthermore, two of three obtained samples of purportedly novel NPS were identified as already documented substances sold under a different name. However, the third characterized substance sold as "MPF-47700" was a novel, yet uncharacterized, NPS. Finally, we received a single undeclared substance, later identified as 5F-ADB. In addition to chemical analysis of the nine obtained NPS samples, the methodology used also yielded contextual information about the accessibility of NPS on the dark web, the associated purchase process, and the modus operandi of three NPS vendors. Direct participation in dark web marketplaces seems to provide additional layers of information useful for forensic studies.

• Klíčová slova
• Dream Market, MPF-47700, dark web, darknet, new psychoactive substances,
• MeSH
• hmotnostní spektrometrie MeSH
• internet MeSH
• lidé MeSH
• magnetická rezonanční spektroskopie MeSH
• obchodování s drogami * MeSH
• odhalování abúzu drog MeSH
• psychotropní léky analýza   zásobování a distribuce   MeSH
• spektrofotometrie ultrafialová MeSH
• zakázané drogy analýza   zásobování a distribuce   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• psychotropní léky MeSH
• zakázané drogy MeSH

Out of six samples of wastewater produced in the dairy industry, taken in 2017 at various places of dairy operations, 86 bacterial strains showing decarboxylase activity were isolated. From the wastewater samples, the species of genera Staphylococcus, Lactococcus, Enterococcus, Microbacterium, Kocuria, Acinetobacter, Pseudomonas, Aeromonas, Klebsiella and Enterobacter were identified by the MALDI-TOF MS and biochemical methods. The in vitro produced quantity of eight biogenic amines (BAs) was detected by the HPLC/UV-Vis method. All the isolated bacteria were able to produce four to eight BAs. Tyramine, putrescine and cadaverine belonged to the most frequently produced BAs. Of the isolated bacteria, 41% were able to produce BAs in amounts >100 mg L-1. Therefore, wastewater embodies a potential vector of transmission of decarboxylase positive microorganisms, which should be taken into consideration in hazard analyses within foodstuff safety control. The parameters of this wastewater (contents of nitrites, nitrates, phosphates, and proteins) were also monitored.

• Klíčová slova
• bacteria, biogenic amines, decarboxylase activity, wastewater,
• MeSH
• Acinetobacter MeSH
• Aeromonas MeSH
• biogenní aminy chemie   MeSH
• chemické látky znečišťující vodu chemie   izolace a purifikace   MeSH
• Enterobacter MeSH
• Enterococcus MeSH
• karboxylyasy chemie   MeSH
• Klebsiella MeSH
• Lactobacillus MeSH
• Lactococcus MeSH
• Microbacterium MeSH
• mikrobiologie vody MeSH
• mlékárenství * MeSH
• odpadní voda analýza   mikrobiologie   MeSH
• Pediococcus MeSH
• Pseudomonas MeSH
• spektrofotometrie ultrafialová MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
• Staphylococcus MeSH
• Streptococcus MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Evropa MeSH
• Názvy látek
• biogenní aminy MeSH
• chemické látky znečišťující vodu MeSH
• karboxylyasy MeSH
• odpadní voda MeSH

A sulphonamidic moiety was utilized as an electron-withdrawing group for enhancement of anion complexation features of urea-based receptors. A series of receptors varying in acidity of sulphonamidic and urea NH groups was synthesized and thoroughly tested. The individual complexation properties reflect deprotonation/complexation equilibrium in a given molecule as a function of the substitution. The receptors containing electron-donating groups in conjugation to the sulphonamidic moiety showed higher association constants towards H2 PO4- and carboxylate anions, while those containing electron-withdrawing groups inclined to deprotonation of sulphonamidic NH. The deprotonation issue can be avoided by alkylation at the early step of receptor synthesis or it can be utilized for insertion of suitable groups that enable its anchoring on various substrates to form more elaborated receptor structures.

• Klíčová slova
• anion recognition, electron-withdrawing groups, host-guest systems, sulphonamides, urea-based receptors,
• MeSH
• alkylace MeSH
• anionty MeSH
• elektrony MeSH
• kyseliny fosforečné chemie   MeSH
• močovina chemie   MeSH
• protonová magnetická rezonanční spektroskopie MeSH
• protony MeSH
• spektrofotometrie ultrafialová MeSH
• sulfonamidy chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• anionty MeSH
• kyseliny fosforečné MeSH
• močovina MeSH
• phosphoric acid MeSH Prohlížeč
• protony MeSH
• sulfonamidy MeSH