Lipids from microorganisms, and especially lipids from Archaea, are used as taxonomic markers. Unfortunately, knowledge is very limited due to the uncultivability of most Archaea, which greatly reduces the importance of the diversity of lipids and their ecological role. One possible solution is to use lipidomic analysis. Six radioactive sources were investigated, two of which are surface (Wettinquelle and Radonka) and four deep from the Svornost mine (Agricola, Behounek, C1, and Curie). A total of 15 core lipids and 82 intact polar lipids were identified from the membranes of microorganisms in six radioactive springs. Using shotgun lipidomics, typical Archaea lipids were identified in spring water, namely dialkyl glycerol tetraethers, archaeol, hydroxyarchaeol and dihydroxyarchaeol. Diverse groups of polar heads were formed in archaeal IPLs, whose polar heads are formed mainly by hexose, deoxyhexose, and phosphoglycerol. The analysis was performed using shotgun lipidomics and the structure of all molecular species was confirmed by tandem mass spectrometry. After acid hydrolysis, a mixture of polar compounds was obtained from the polar head. Further analysis by GC-MS confirmed that the carbohydrates were glucose and rhamnose. Analysis by HPLC-MS of diastereoisomers of 2-(polyhydroxyalkyl)-3-(O-tolylthiocarbamoyl)thiazolidine-4(R)-carboxylates revealed that both L-rhamnose and D-glucose are present in spring samples only in varying amounts. The glycoside composition depends on the type of spring, that is, Wettinquelle and Radonka springs are basically shallow groundwater, while the samples from the Svornost mine are deep groundwater and do not contain glycosides with rhamnose. This method enables quick screening for characteristic Archaea lipids, allowing decisions on whether to pursue further analyses, such as metagenomic analysis, to directly confirm the presence of Archaea.
Ceramides are key components of the skin's permeability barrier. In atopic dermatitis, pathological hydrolysis of ceramide precursors - glucosylceramides and sphingomyelin - into lysosphingolipids, specifically glucosylsphingosine (GS) and sphingosine-phosphorylcholine (SPC), and free fatty acids (FFAs) has been proposed to contribute to impaired skin barrier function. This study investigated whether replacing ceramides with lysosphingolipids and FFAs in skin lipid barrier models would exacerbate barrier dysfunction. When applied topically to human stratum corneum sheets, SPC and GS increased water loss, decreased electrical impedance, and slightly disordered lipid chains. In lipid models containing isolated human stratum corneum ceramides, reducing ceramides by ≥ 30% significantly increased permeability to four markers, likely due to loss of long-periodicity phase (LPP) lamellae and phase separation within the lipid matrix, as revealed by X-ray diffraction and infrared spectroscopy. However, when the missing ceramides were replaced by lysosphingolipids and FFAs, no further increase in permeability was observed. Conversely, these molecules partially mitigated the negative effects of ceramide deficiency, particularly with 5%-10% SPC, which reduced permeability even compared to control with "healthy" lipid composition. These findings suggest that while ceramide deficiency is a key factor in skin barrier dysfunction, the presence of lysosphingolipids and FFAs does not aggravate lipid structural or functional damage, but may provide partial compensation, raising further questions about the behavior of lyso(sphingo)lipids in rigid multilamellar lipid environments, such as the stratum corneum, that warrant further investigation.
- MeSH
- Models, Biological MeSH
- Ceramides * metabolism MeSH
- Phosphorylcholine analogs & derivatives MeSH
- Skin * metabolism MeSH
- Fatty Acids, Nonesterified metabolism MeSH
- Humans MeSH
- Lysophospholipids metabolism MeSH
- Permeability drug effects MeSH
- Sphingosine analogs & derivatives metabolism MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Poly(ɛ-caprolactone) (PCL) is a biocompatible, biodegradable, and highly mechanically resilient FDA-approved material (for specific biomedical applications, e.g. as drug delivery devices, in sutures, or as an adhesion barrier), rendering it a promising candidate to serve bone tissue engineering. However, in vivo monitoring of PCL-based implants, as well as biodegradable implants in general, and their degradation profiles pose a significant challenge, hindering further development in the tissue engineering field and subsequent clinical adoption. To address this, photo-cross-linkable mechanically resilient PCL networks are developed and functionalized with a radiopaque monomer, 5-acrylamido-2,4,6-triiodoisophthalic acid (AATIPA), to enable non-destructive in vivo monitoring of PCL-based implants. The covalent incorporation of AATIPA into the crosslinked PCL networks does not significantly affect their crosslinking kinetics, mechanical properties, or thermal properties, but it increases their hydrolysis rate and radiopacity. Complex and porous 3D designs of radiopaque PCL networks can be effectively monitored in vivo. This work paves the way toward non-invasive monitoring of in vivo degradation profiles and early detection of potential implant malfunctions.
- MeSH
- Biocompatible Materials chemistry MeSH
- Mice MeSH
- Polyesters * chemistry MeSH
- Porosity MeSH
- Materials Testing MeSH
- Tissue Engineering methods MeSH
- Tissue Scaffolds * chemistry MeSH
- Absorbable Implants MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
The present study has undertaken the isolation of marine yeasts from mangrove sediment samples and their ability to produce alkaline protease enzymes. A total of 14 yeast isolates were recovered on yeast-malt agar (YMA) and yeast extract peptone dextrose (YEPD) agar medium. After screening for proteolytic activity on skim milk agar, marine yeast isolate, AKB-1 exhibited a hydrolysis zone of 18 mm. Optimal conditions for the enzyme production from yeast isolate AKB-1 were at 30 °C, pH 8, fructose as carbon source, potassium nitrate as nitrogen source, and 25% saline concentration. Under the optimal conditions, the protease enzyme activity of the isolate AKB-1 was observed to be 978 IU/mL. The structural and functional analysis was carried out through FTIR and HPLC analysis for the extracted protease enzyme. Furthermore, the enzyme produced was partially purified by solvent extraction using ethyl acetate and ammonium sulfate precipitation (3.4-fold) followed by dialysis (56.8-fold). The molecular weight of the purified enzyme was observed to be around 60 kDa using SDS-PAGE. The extracted protein showed good antibacterial activity against six different clinical bacterial pathogens and the highest against Bacillus cereus (16 ± 0.5 mm). The extracted protease enzyme was revealed to remove blood stains from cloth within 20 min of application similar to the commercial detergent. The marine yeast isolate was further identified as Candida orthopsilosis AKB-1 (Accession number KY348766) through 18S rRNA sequencing, and a phylogenetic tree was generated.
- MeSH
- Anti-Bacterial Agents pharmacology metabolism chemistry isolation & purification MeSH
- Bacillus cereus drug effects MeSH
- Bacterial Proteins * chemistry pharmacology metabolism isolation & purification MeSH
- Candida * enzymology isolation & purification genetics classification MeSH
- Endopeptidases * chemistry metabolism isolation & purification pharmacology MeSH
- Phylogeny MeSH
- Geologic Sediments microbiology MeSH
- Hydrogen-Ion Concentration MeSH
- Culture Media chemistry MeSH
- Microbial Sensitivity Tests MeSH
- Molecular Weight MeSH
- Enzyme Stability MeSH
- Temperature MeSH
- Publication type
- Journal Article MeSH
Given the high incidence of diet-related diseases, including type 2 diabetes and cancer, there is a growing need to explore new strategies for their prevention. Although polyphenols are known to reduce starch digestibility and lower the in vitro glycemic index, their antioxidant capacity and cytotoxic properties, when complexed with starches, remain underexplored. Therefore, this study aimed to investigate the antioxidant activity, total polyphenol content, and cytotoxic potential of polyphenol-starch complexes formed using common dietary polyphenols-(+)-catechin, epigallocatechin gallate, hesperidin, naringenin, trans-ferulic acid, p-coumaric acid, quercetin, and kaempferol-and widely consumed starches from wheat, rice, potato, and maize. Antioxidant activity (FRAP and DPPH) together with the total polyphenols content (Folin-Ciocalteu) were tested: (1) before (undigested) enzymatic hydrolysis of the tested sample; (2) after (digested) enzymatic hydrolysis of the tested sample and (3) after hydrolysis of the sample and its centrifugation (supernatant). Cytotoxicity against colon cancer (Caco-2, HT29) and normal colon (CCD 841CoN) cell lines were determined in vitro by the MTT method. In undigested samples, the highest antioxidant activity was obtained with the addition of quercetin to wheat, rice, and maize starch (6735.8 μmol Fe2+/g d.m., 678.8, 539.4 μmol Trolox/g d.m., respectively), and epigallocatechin gallate to wheat, rice, potato, and maize starch (692.1, 538.0, 625.8, 573.6 μmol Trolox/g d.m., respectively). In digested samples, the highest antioxidant activity was obtained with the addition of quercetin to wheat and rice starch (2104.5 μmol Fe2+/g d.m., 742.1 μmol Trolox/g d.m., respectively). In the case of the natant of the digested samples, the highest value was recorded for the addition of (+)-catechin to potato starch and trans-ferulic acid to maize starch (823.7 μmol Fe2+/g d.m., 245.1 μmol Trolox/g d.m., respectively). The addition of quercetin to wheat and rice starch and (+)-catechin to potato starch (0.239, 0.151, 0.085 g gallic acid/g d.m., respectively) resulted in the highest total polyphenol content. Furthermore, quercetin demonstrated the most significant level of cytotoxic activity against the tumor cell line Caco-2 (IC50 = 275.6 μg/mL; potato starch). Overall, quercetin was identified as the most significant or one of the most significant for all parameters evaluated.
- MeSH
- Antioxidants * pharmacology chemistry MeSH
- HT29 Cells MeSH
- Caco-2 Cells MeSH
- Catechin analogs & derivatives MeSH
- Zea mays chemistry MeSH
- Humans MeSH
- Cell Line, Tumor MeSH
- Polyphenols * chemistry pharmacology MeSH
- Oryza chemistry MeSH
- Starch * chemistry pharmacology MeSH
- Cell Survival drug effects MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Despite being present in many drugs, guanylhydrazones and semicarbazones are two functional groups that have been little investigated as potential therapeutic strategies for the treatment of Alzheimer's disease (AD). For this reason, we initiated the synthesis and evaluation of these compounds as potential anticholinesterase agents, aiming to offer new alternatives for drug development against AD. In the severe phase of AD butyrylcholinesterase (BChE) becomes the main enzyme responsible for the hydrolysis of acetylcholine (ACh). Therefore, in this project, we present the results of BChE inhibitory activity, enzyme kinetics, cytotoxicity, and molecular modeling studies for three guanylhydrazone and two semicarbazone derivatives that were previously synthesized and evaluated as acetylcholinesterase (AChE) inhibitors. Among the compounds tested, guanylhydrazones (1, 2, and 3) showed inhibitory activity against BChE, exhibiting a mixed non-competitive inhibition profile. Specifically, compound 2 (phenanthrenequinone) demonstrated superior inhibitory potency with an IC50 of 0.68 μM, compared to compound 1 (acridinone) with an IC50 of 3.87 μM, and compound 3 (benzodioxole) with an IC50 of 101.7 μM. In contrast, semicarbazones (4 and 5) showed no BChE inhibition up to the highest concentration tested (300 μM). Importantly, all five compounds were found to be non-cytotoxic. Our results suggest that these compounds have potential as drug prototypes targeting different phases of AD. Compounds 3, 4, and 5 may be more effective in the early phase, when AChE activity remains high; compound 1 could be useful in the intermediate phase; and compound 2 appears particularly promising for the severe phase, when BChE plays a more dominant role.
- MeSH
- Acetylcholinesterase metabolism chemistry MeSH
- Alzheimer Disease * drug therapy MeSH
- Butyrylcholinesterase metabolism chemistry MeSH
- Cholinesterase Inhibitors * chemistry pharmacology metabolism therapeutic use chemical synthesis MeSH
- Hydrazones * chemistry pharmacology MeSH
- Kinetics MeSH
- Humans MeSH
- Models, Molecular MeSH
- Drug Design * MeSH
- Semicarbazones * chemistry pharmacology metabolism MeSH
- Molecular Docking Simulation MeSH
- Structure-Activity Relationship MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
We present a method for the amination of enolizable and non-enolizable ketones in the alpha (or beta) position to the carbonyl group. This approach is based on the conversion of the corresponding cyanohydrins to carbonazidates, precursors for thermal intramolecular nitrene insertion reactions into the adjacent C-H bond. Hydrolysis of the resulting carbamates under basic conditions with simultaneous regeneration of the carbonyl group yields amino ketones.
- Publication type
- Journal Article MeSH
The behavior of chemical warfare agents (CWAs) on urban materials, such as concrete, significantly impacts forensic and military responses to chemical incidents. This study examined the persistence and degradation mechanisms of sarin (GB), soman (GD), and sulfur mustard (HD) on three types of commonly used concrete with varying water-cement ratios. Over two months, we evaluated the effects of concrete composition, temperature, and fragment size on CWA behavior. Half-lives and activation energies for CWA dissipation were calculated under various conditions. Results showed that concrete properties and external temperature strongly influenced dissipation rates. G-series agents underwent rapid hydrolysis, forming methylphosphonates, while HD degradation involved elimination, nucleophilic substitution, and oxidation, producing several previously unreported byproducts. Smaller concrete fragments increased recovery values and accelerated degradation due to greater surface area exposure, and higher temperatures further enhanced dissipation rates, particularly for volatile agents. Differences in dissipation among concrete types were linked to their physical and chemical properties, notably water-cement ratios. This study highlights the challenges of detecting CWAs due to their rapid penetration and transformation in concrete and provides insights for improving sampling, identification, and decontamination strategies under realistic conditions.
- Publication type
- Journal Article MeSH
Iceberg lettuce is one of the most consumed leafy vegetables, which is often treated by different pesticides against pests and diseases. The aim of this study was to describe the fate of 25 pesticides (16 fungicides, 7 insecticides and 2 herbicides) based on quantitative analysis of the parent compounds and targeted screening of their (bio)transformation products. Mathematical models describing a decrease in pesticide residue levels were proposed for 24 pesticides using a first-order kinetic equation. These models provide the data needed to predict consumer exposure associated with the consumption of conventionally grown iceberg lettuce. At harvest, concentrations of most pesticides were dropped under the established EU maximum residue levels, except for flonicamid, fluazifop and pyriproxyfen. A total of 113 pesticide metabolites and degradation products were detected and tentatively identified in extracts prepared by an optimized extraction procedure, i.e., the acidified QuEChERS method. Several products of reactions such as hydrolysis, dealkylation, dehalogenation and/or oxidation-reduction, originated either from various physicochemical processes, or within Phase I pesticide metabolism were detected. Additionally, numerous conjugates with hexose, malonic acid or acetic acid formed during PhaseII of pesticide metabolism were found. In this way, a deeper understanding of specific pesticide degradation mechanisms is facilitated. In addition, it is easier to track the history of pesticide treatment.
- MeSH
- Herbicides analysis MeSH
- Kinetics MeSH
- Food Contamination * analysis MeSH
- Pesticide Residues * analysis MeSH
- Lactuca * chemistry MeSH
- Publication type
- Journal Article MeSH
The Sec translocon is a highly conserved membrane assembly for polypeptide transport across, or into, lipid bilayers. In bacteria, secretion through the core channel complex-SecYEG in the inner membrane-is powered by the cytosolic ATPase SecA. Here, we use single-molecule fluorescence to interrogate the conformational state of SecYEG throughout the ATP hydrolysis cycle of SecA. We show that the SecYEG channel fluctuations between open and closed states are much faster (~20-fold during translocation) than ATP turnover, and that the nucleotide status of SecA modulates the rates of opening and closure. The SecY variant PrlA4, which exhibits faster transport but unaffected ATPase rates, increases the dwell time in the open state, facilitating pre-protein diffusion through the pore and thereby enhancing translocation efficiency. Thus, rapid SecYEG channel dynamics are allosterically coupled to SecA via modulation of the energy landscape, and play an integral part in protein transport. Loose coupling of ATP-turnover by SecA to the dynamic properties of SecYEG is compatible with a Brownian-rachet mechanism of translocation, rather than strict nucleotide-dependent interconversion between different static states of a power stroke.
- MeSH
- Adenosine Triphosphate metabolism MeSH
- Adenosine Triphosphatases genetics metabolism MeSH
- Bacterial Proteins * metabolism MeSH
- Nucleotides metabolism MeSH
- SecA Proteins metabolism MeSH
- Escherichia coli Proteins * metabolism MeSH
- SEC Translocation Channels chemistry MeSH
- Protein Transport MeSH
- Publication type
- Journal Article MeSH
