The biosynthesis of the lincosamide antibiotics lincomycin A and celesticetin involves the pyridoxal-5'-phosphate (PLP)-dependent enzymes LmbF and CcbF, which are responsible for bifurcation of the biosynthetic pathways. Despite recognizing the same S-glycosyl-L-cysteine structure of the substrates, LmbF catalyses thiol formation through β-elimination, whereas CcbF produces S-acetaldehyde through decarboxylation-coupled oxidative deamination. The structural basis for the diversification mechanism remains largely unexplored. Here we conduct structure-function analyses of LmbF and CcbF. X-ray crystal structures, docking and molecular dynamics simulations reveal that active-site aromatic residues play important roles in controlling the substrate binding mode and the reaction outcome. Furthermore, the reaction selectivity and oxygen-utilization of LmbF and CcbF were rationally engineered through structure- and calculation-based mutagenesis. Thus, the catalytic function of CcbF was switched to that of LmbF, and, remarkably, both LmbF and CcbF variants gained the oxidative-amidation activity to produce an unnatural S-acetamide derivative of lincosamide.
Background/Objectives: Rivaroxaban, an oral anticoagulant, shows poor aqueous solubility, posing significant challenges to its bioavailability and therapeutic efficiency. The present study investigates the improvement of rivaroxaban's solubility through the formation of different inclusion complexes with three cyclodextrin derivatives, such as β-cyclodextrin (β-CD), methyl-β-cyclodextrin (Me-β-CD), and hydroxypropyl-β-cyclodextrin (HP-β-CD) prepared by lyophilization in order to stabilize the complexes and improve dissolution characteristics of rivaroxaban. Methods: The physicochemical properties of the individual compounds and the three lyophilized complexes were analysed using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Results: FTIR spectra confirmed the formation of non-covalent interactions between rivaroxaban and the cyclodextrins, suggesting successful encapsulation into cyclodextrin cavity. SEM images revealed a significant morphological transformation from the crystalline structure of pure rivaroxaban and cyclodextrins morphologies to a more porous and amorphous matrix in all lyophilized complexes. XRD patterns indicated a noticeable reduction in drug crystallinity, supporting enhanced potential of the drug solubility. TGA analysis demonstrated improved thermal stability in the inclusion complexes compared to the individual drug and cyclodextrins. Pharmacotechnical evaluation revealed that the obtained formulations (by comparison with physical mixtures formulations) possessed favorable bulk and tapped density values, suitable compressibility index, and good flow properties, making all suitable for direct compression into solid dosage forms. Conclusions: The improved cyclodextrins formulation characteristics, combined with enhanced dissolution profiles of rivaroxaban comparable to commercial Xarelto® 10 mg, highlight the potential of both cyclodextrin inclusion and lyophilization technique as synergistic strategies for enhancing the solubility and drug release of rivaroxaban.
- Publication type
- Journal Article MeSH
TiO2 nanoparticles (NPs) are extensively used in various applications, highlighting the importance of ongoing research into their effects. This work belongs among rare whole-body inhalation studies investigating the effects of TiO2 NPs on mice. Unlike previous studies, the concentration of TiO2 NPs in the inhalation chamber (130.8 μg/m3) was significantly lower. This 11-week study on mice confirmed in vivo the presence of TiO2 NPs in lung macrophages and type II pneumocytes including their intracellular localization by using the electron microscopy and the state-of-the-art methods detecting NPs' chemical identity/crystal structure, such as the energy-dispersed X-ray spectroscopy (EDX), cathodoluminescence (CL), and detailed diffraction pattern analysis using powder nanobeam diffraction (PNBD). For the first time in inhalation study in vivo, the alterations in erythrocyte morphology with evidence of echinocytes and stomatocytes, accompanied by iron accumulation in spleen, liver, and kidney, are reported following NP's exposure. Together with the histopathological evidence of hyperaemia in the spleen and kidney, and haemosiderin presence in the spleen, the finding of NPs containing iron might suggest the increased decomposition of damaged erythrocytes. The detection of TiO2 NPs on erythrocytes through CL analysis confirmed their potential systemic availability. On the contrary, TiO2 NPs were not confirmed in other organs (spleen, liver, and kidney); Ti was detected only in the kidney near the detection limit.
- MeSH
- Administration, Inhalation MeSH
- Erythrocytes * drug effects pathology MeSH
- Inhalation Exposure * adverse effects MeSH
- Metal Nanoparticles * toxicity MeSH
- Mice MeSH
- Nanoparticles * toxicity MeSH
- Lung * drug effects metabolism pathology MeSH
- Toxicity Tests, Subchronic MeSH
- Titanium * toxicity pharmacokinetics administration & dosage MeSH
- Tissue Distribution MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
The vertebrate visual cycle hinges on enzymatically converting all-trans-retinol (at-ROL) into 11-cis-retinal (11c-RAL), the chromophore that binds to opsins in photoreceptors, forming light-responsive pigments. When struck by a photon, these pigments activate the phototransduction pathway and initiate the process of vision. The enzymatic isomerization of at-ROL, crucial for restoring the visual pigments and preparing them to receive new light stimuli, relies on various enzymes found in both the photoreceptors and retinal pigment epithelium cells. To function effectively, retinoids must shuttle between these two cell types. Retinol-binding protein 3 (RBP3), located in the interphotoreceptor matrix, probably plays a pivotal role in this transport mechanism. Comprised of four retinoid-binding modules, RBP3 also binds fatty acids, potentially aiding retinal function by facilitating the loading and unloading of different retinoids at specific cell types thereby directing the cycle. In this study, we present a 3.67 Å cryoEM structure of porcine RBP3, along with molecular docking analysis and corroborative in-solution small-angle X-ray scattering data for titration of RBP3 with relevant ligands, that also give insights on RBP3 conformational adaptability.
- MeSH
- X-Ray Diffraction MeSH
- Cryoelectron Microscopy methods MeSH
- Protein Conformation MeSH
- Scattering, Small Angle * MeSH
- Models, Molecular MeSH
- Eye Proteins MeSH
- Swine MeSH
- Retinol-Binding Proteins * chemistry metabolism MeSH
- Molecular Docking Simulation MeSH
- Protein Binding MeSH
- Vitamin A metabolism chemistry MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
The novel diiron amine complexes [Fe2Cp2(CO)(NH2R')(μ-CO){μ-CN(Me)(Cy)}]CF3SO3 [R' = H, 3; Cy, 4; CH2CH2NH2, 5; CH2CH2NMe2, 6; CH2CH2(4-C6H4OMe), 7; CH2CH2(4-C6H4OH), 8; Cp = η5-C5H5, Cy = C6H11 = cyclohexyl] were synthesized in 49-92 % yields from [Fe2Cp2(CO)2(μ-CO){μ-CN(Me)(Cy)}]CF3SO3, 1a, using a straightforward two-step procedure. They were characterized by IR and multinuclear NMR spectroscopy, and the structure of 7 was confirmed through X-ray diffraction analysis. Complexes 3-8 and the acetonitrile adducts [Fe2Cp2(CO)(NCMe)(μ-CO){μ-CN(Me)(R)}]CF3SO3 (R = Cy, 2a; Me, 2b; Xyl = 2,6-C6H3Me2, 2c) were assessed for their water solubility, octanol-water partition coefficient and stability in physiological-like solutions. The in vitro antiproliferative activity of 2a-c and 3-8 was tested on seven human cancer cell lines (A2780, A2780R, PC3, A549, MCF7, HOS and HT-29), while the selectivity was evaluated using normal MRC-5 cells. Overall, the complexes exhibited variable cytotoxicity, with IC50 values reaching the low micromolar range for 3, 7 and 8 in A2780 and A2780R cells, along with significant selectivity. Targeted experiments covered cell cycle modification, induction of cell death, mitochondrial membrane potential, ROS production and interaction with DNA and bovine serum albumin (BSA) as a model protein. The interaction of 3 with BSA was further investigated through computational studies. Results showed a negligible increase in intracellular ROS levels (except for 2b) and insignificant changes in mitochondrial membrane potential.
- MeSH
- Amines chemistry pharmacology MeSH
- Coordination Complexes chemistry pharmacology chemical synthesis MeSH
- Humans MeSH
- Ligands MeSH
- Molecular Structure MeSH
- Cell Line, Tumor MeSH
- Cell Proliferation * drug effects MeSH
- Antineoplastic Agents * pharmacology chemistry chemical synthesis MeSH
- Drug Screening Assays, Antitumor * MeSH
- Dose-Response Relationship, Drug MeSH
- Structure-Activity Relationship MeSH
- Iron chemistry MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
INTRODUCTION: Ziziphora clinopodioides subsp. bungeana (Juz.) Rech.f. is used in traditional medicine for various purposes. Previous phytochemical studies focused on phenolic compounds, but triterpenoids were almost overlooked. OBJECTIVE: The study focused on the isolation of compounds with dual antidiabetic activity from the aerial parts of Z. clinopodioides subsp. bungeana. MATERIALS AND METHODS: Separation of CHCl3-soluble fraction by silica gel column chromatography using different mobile phases and purification of compounds by semi-preparative HPLC or preparative TLC. The structures of pure compounds were elucidated by 1D and 2D NMR experiments along with HRMS. Compound 1 was additionally identified by the single crystal X-ray diffraction method. α-Glucosidase inhibitory assay and GLUT4 expression and translocation in C2C12 myotubes were conducted to evaluate antidiabetic potential of isolated compounds. RESULTS: This phytochemical study led to the isolation of 20 compounds, including a unique monoterpene diperoxy dimer (1). Compounds 7 and 9-11 displayed more potent α-glucosidase inhibitory activity (IC50 45.3-135.3 μM) than acarbose used as a positive control (IC50 264.7 μM), while only pomolic acid (5) increased GLUT4 translocation in C2C12 myotubes in a significant manner. CONCLUSION: Extensive chromatographic separation led to the isolation and identification of a unique monoterpene diperoxy dimer (1) from aerial parts of Z. clinopodioides subsp. bungeana. Some triterpenes inhibited α-glucosidase, another increased GLUT4 translocation. Although none of the isolated compounds demonstrated dual antidiabetic activity, selected triterpenes proved to be potent antidiabetic agents in vitro.
- MeSH
- alpha-Glucosidases metabolism MeSH
- Cell Line MeSH
- Lamiaceae * chemistry MeSH
- Hypoglycemic Agents * pharmacology chemistry isolation & purification MeSH
- Glycoside Hydrolase Inhibitors pharmacology isolation & purification chemistry MeSH
- Mice MeSH
- Plant Components, Aerial chemistry MeSH
- Glucose Transporter Type 4 metabolism MeSH
- Plant Extracts chemistry pharmacology MeSH
- Triterpenes * pharmacology chemistry isolation & purification MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Free radical polymerization technique was used to formulate Poloxamer-188 based hydrogels for controlled delivery. A total of seven formulations were formulated with varying concentrations of polymer, monomer ad cross linker. In order to assess the structural properties of the formulated hydrogels, Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), Scanning electron microscopy (SEM), and X-ray diffraction (XRD) were carried out. To assess the effect of pH on the release of the drug from the polymeric system, drug release studies were carried in pH 1.2 and 7.4 and it was found that release of the drug was significant in pH 7.4 as compared to that of pH 1.2 which confirmed the pH responsiveness of the system. Different kinetic models were also applied to the drug release to evaluate the mechanism of the drug release from the system. To determine the safety and biocompatibility of the system, toxicity study was also carried out for which healthy rabbits were selected and formulated hydrogels were orally administered to the rabbits. The results obtained suggested that the formulated poloxamer-188 hydrogels are biocompatible with biological system and have the potential to serve as controlled drug delivery vehicles.
- MeSH
- Acrylic Resins * chemistry MeSH
- Calorimetry, Differential Scanning MeSH
- X-Ray Diffraction MeSH
- Hydrogels * chemistry MeSH
- Hydrogen-Ion Concentration MeSH
- Rabbits MeSH
- Drug Delivery Systems MeSH
- Delayed-Action Preparations chemistry pharmacokinetics MeSH
- Microscopy, Electron, Scanning MeSH
- Drug Carriers chemistry MeSH
- Poloxamer * chemistry MeSH
- Spectroscopy, Fourier Transform Infrared MeSH
- Thermogravimetry MeSH
- Timolol * administration & dosage pharmacokinetics chemistry MeSH
- Drug Liberation MeSH
- Animals MeSH
- Check Tag
- Rabbits MeSH
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
We report avian cervical vertebrae from the Quercy fissure fillings in France, which are densely covered with villi-like tubercles. Two of these vertebrae stem from a late Eocene site, another lacks exact stratigraphic data. Similar cervical vertebrae occur in avian species from Eocene fossils sites in Germany and the United Kingdom, but the new fossils are the only three-dimensionally preserved vertebrae with pronounced surface sculpturing. So far, the evolutionary significance of this highly bizarre morphology, which is unknown from extant birds, remained elusive, and even a pathological origin was considered. We note the occurrence of similar structures on the skull of the extant African rodent Lophiomys and detail that the tubercles represent true osteological features and characterize a distinctive clade of Eocene birds (Perplexicervicidae). Micro-computed tomography (μCT) shows the tubercles to be associated with osteosclerosis of the cervical vertebrae, which have a very thick cortex and much fewer trabecles and pneumatic spaces than the cervicals of most extant birds aside from some specialized divers. This unusual morphology is likely to have served for strengthening the vertebral spine in the neck region, and we hypothesize that it represents an anti-predator adaptation against the craniocervical killing bite ("neck bite") that evolved in some groups of mammalian predators. Tuberculate vertebrae are only known from the Eocene of Central Europe, which featured a low predation pressure on birds during that geological epoch, as is evidenced by high numbers of flightless avian species. Strengthening of the cranialmost neck vertebrae would have mitigated attacks by smaller predators with weak bite forces, and we interpret these vertebral specializations as the first evidence of "internal bony armor" in birds.
Introduction: The present study aimed to investigate the association between the five-factor personality model (FFM), physical fitness, and physical activity (PA), and the effect of firefighting skills training on physical condition in firefighter recruits. Methods: Data on 58 newly-recruited firefighters from the CELSPAC–FIREexpo human biomonitoring study were used. The sampling protocol was structured in the entry phase testing on the 5th week of training, and final testing on the 10th week of training. During the testing, participants filled out the International Physical Activity Questionnaire (IPAQ) and the Revised NEO Personality Inventory, and underwent analysis of body composition using Dual energy X-Ray Absorptiometry (DXA), a physical work capacity test (PWC 170), a muscular strength test (one repetition maximum bench press (1RM BP) and squat (1RM S)) and the measurement of body weight and height to calculate body mass index (BMI). Associations between study parameters were determined using the Spearman correlation. Results: Extraversion (E) was positively associated with time spent in vigorous physical activity (VPA) and Openness to Experience (O) was negatively associated with time spent sitting. Openness to Experience was also positively associated with BMI and lean mass differences between entry and output measurements. Furthermore, 1 RM S significantly increased during the training program. Conclusion: The observed association between personality from FFM and PA levels in the present study was lower than in the general population reported by other studies. The positive association between E and VPA suggests that using FFM and the relationship between personality and physical fitness as one of the criteria for the selection of suitable recruits may be beneficial.
INTRODUCTION: Fibroblast growth factor 20 (Fgf20), a member of the Fgf9 subfamily, was identified as an important regulator of bone differentiation and homeostasis processes. However, the role of Fgf20 in bone physiology has not been approached yet. Here we present a comprehensive bone phenotype analysis of mice with functional ablation of Fgf20. METHODS: The study conducts an extensive analysis of Fgf20 knockout mice compared to controls, incorporating microCT scanning, volumetric analysis, Fgf9 subfamily expression and stimulation experiment and histological evaluation. RESULTS: The bone phenotype could be detected especially in the area of the lumbar and caudal part of the spine and in fingers. Regarding the spine, Fgf20-/- mice exhibited adhesions of the transverse process of the sixth lumbar vertebra to the pelvis as well as malformations in the distal part of their tails. Preaxial polydactyly and polysyndactyly in varying degrees of severity were also detected. High resolution microCT analysis of distal femurs and the fourth lumbar vertebra showed significant differences in structure and mineralization in both cortical and trabecular bone. These findings were histologically validated and may be associated with the expression of Fgf20 in chondrocytes and their progenitors. Moreover, histological sections demonstrated increased bone tissue formation, disruption of Fgf20-/- femur cartilage, and cellular-level alterations, particularly in osteoclasts. We also observed molar dysmorphology, including root taurodontism, and described variations in mineralization and dentin thickness. DISCUSSION: Our analysis provides evidence that Fgf20, together with other members of the Fgf9 subfamily, plays a crucial regulatory role in skeletal development and bone homeostasis.
- MeSH
- Phenotype MeSH
- Fibroblast Growth Factors * metabolism genetics MeSH
- Calcification, Physiologic MeSH
- Bone and Bones metabolism pathology diagnostic imaging abnormalities MeSH
- Mice, Inbred C57BL MeSH
- Mice, Knockout * MeSH
- Mice MeSH
- Osteogenesis MeSH
- X-Ray Microtomography MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Mice MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
