Search Results (665)

Background: Standardized and ethically compliant animal models remain essential for improving translational research in Alzheimer’s disease. Although Aβ_1–42-induced rodent models are widely used, methodological variability continues to limit reproducibility. Methods: We explored the feasibility of a stereotactic intrahippocampal Aβ_1–42 rat model established by bilaterally injecting pre-aggregated peptide into the hippocampus of adult Sprague Dawley rats. Model feasibility and targeting accuracy were assessed intraoperatively. Cognitive performance was evaluated using the Y-maze for spatial recognition memory and the novel object recognition (NOR) test. Histological examination was performed using hematoxylin–eosin (H&E) and Congo red staining to assess cytoarchitecture and to provide supportive evidence of amyloid-like deposits. Results: The surgical procedure was well-tolerated, and the injected animals showed reduced performance in behavioural testing, including reduced spatial recognition memory in the Y-maze and decreased discrimination indices in the NOR test. The animals also showed histological changes, including Congo red-positive birefringent structures consistent with amyloid-like congophilic material. Conclusions: This study presents a feasible experimental framework for intrahippocampal Aβ_1–42 administration, showing behavioural and histological changes under the present experimental conditions. However, further validation, including sham-operated controls and molecular characterization, will be required before these findings can be interpreted as specific to Aβ-driven pathology. Full article

A 27-year-old male presented with chronic diarrhea, bloating, and abdominal pain since age 13. Initially attributed to lactose intolerance, treated with dairy-free diet, symptoms persisted despite negative workup—normal celiac serology, stool studies, and abdominal ultrasound. Recent symptoms included severe diarrhea, fatigue, weakness, 8 kg weight loss, hair loss, elevated IgE and fecal calprotectin. Gastroscopy showed flattened, granular gastric mucosa with focal hyperemia in the antrum and greater curvature. Histology revealed severe chronic inactive H. pylori-negative gastritis with a prominent subepithelial collagen band (verified by Crossmon’s trichrome), confirming collagenous gastritis—a rare entity first described in 1989. The condition has a slight female predominance and bimodal age peaks (adolescence and >60 years). Symptoms are nonspecific, including abdominal pain, diarrhea, weight loss and anemia. Pediatric cases often feature nodular mucosa and anemia; adults more commonly present with watery diarrhea, sometimes linked to collagenous colitis. Diagnosis requires histological features including patchy subepithelial collagen band ≥ 10 μm thick, lymphocytic or eosinophilic infiltration of the lamina propria, epithelial changes and entrapped capillaries. Patterns include atrophic, lymphocytic-like, and eosinophil-rich. Crossmon’s or Masson’s trichrome, Congo red, and tenascin immunohistochemistry aid in proving collagen and excluding amyloidosis. Treatment is mainly symptomatic or with proton pump inhibitors; corticosteroids may be effective in refractory cases. Full article

Lophatherum gracile Brongn. (L. gracile) has been utilized as a food or medicinal plant for a long time. A series of chemical and spectroscopic methods was used to characterize the extracted and purified L. gracile polysaccharide (LGP). Its in vivo antitumor activity in the H22 tumor-bearing mice model was studied. LGP has a molecular weight of 1.42 × 10⁶ Da and is mainly composed of arabinose (Ara), galactose (Gal), xylose (Xyl), and other monosaccharides. NMR spectra suggest that LGP may be composed of 1,3-β-Galp and 1,3,6-β-Galp main chains, and a side chain formed by a 1,5-α-Araf short chain. The termini are composed of T-α-Araf, while [→4) -α-GalpA-(1→2)-α-Rhap-(1→] are attached to the backbone as short side chains, and the other monosaccharides are an arabinogalactan composed of the termini. SEM and AFM revealed that LGP presents a lamellar morphology with smooth surfaces and notable molecular aggregation. The Congo red assay, CD spectroscopy, and XRD collectively indicated the absence of a triple helix conformation and an overall amorphous structure in LGP. Compared with the model group, LGP treatment improved body responses, immune organs, and SOD and MDA levels. The tumor cell apoptosis rate in the high-dose LGP group was 50.0%. In the distribution of the tumor cell cycle, the proportions of the S phase were 29.1% and 41.1% in the low-dose LGP and high-dose LGP groups, respectively, compared with 12.2% in the model group. These results suggest that LGP exhibits preliminary antitumor activity, indicating its potential as a candidate for further cancer research. Full article

Functional amyloids are widely distributed in bacteria and play important roles in biofilm formation and microbial physiology. However, most currently known bacterial amyloids have been identified through sequence homology to a limited number of prototype proteins, such as the curli subunit CsgA of Escherichia coli. This approach may overlook amyloidogenic sequences that lack recognizable similarity to these canonical systems. In this study, a cross-species, motif-based computational strategy was used to explore whether conserved sequence features derived from mammalian serum amyloid A (SAA) proteins could provide clues for identifying potential amyloidogenic motifs in bacterial proteomes. Comparative analysis of mammalian SAA isoforms identified a conserved sequence segment with predicted aggregation propensity, within which the hydrophobic motif SIAIILCILIL was observed in murine SAA3. Database searches revealed that similar sequence motifs occur in several proteins encoded by Gram-positive bacteria, including multiple proteins in Clostridioides difficile. To further explore whether C. difficile produces extracellular structures capable of interacting with amyloid-binding dyes, Congo Red-supplemented agar assays were performed. After 48 h of growth, both clinical isolates and a laboratory reference strain exhibited Congo Red-binding colony phenotypes. Because Congo Red binding can arise from several extracellular components and cannot be attributed to a specific protein or sequence motif, these observations should be interpreted cautiously. Taken together, this study presents a motif-based computational framework for identifying candidate amyloidogenic motifs across species and highlights sequence features in bacterial proteomes that may warrant further biochemical and structural investigation. The results should be regarded as hypothesis-generating and provide a basis for future experimental validation of potential amyloid-forming proteins in bacteria. Full article

The increasing discharge of synthetic dyes into industrial wastewater necessitates sustainable and low-cost treatment strategies. This study valorizes orange seed powder (OSP), an abundant agro-food residue, as a novel biosorbent for Congo red (CR) removal through a combined experimental and molecular simulation approach. Raw OSP was prepared solely by drying and grinding, without chemical activation, emphasizing its practical applicability and environmental sustainability. Physicochemical characterization using FTIR, SEM, and EDX confirmed adsorption-induced structural and compositional changes. Batch experiments evaluated the effects of initial dye concentration, adsorbent dosage, pH, temperature, and contact time. Equilibrium data were well fitted by the Langmuir and Freundlich isotherm models (R² ≈ 0.99), with a maximum adsorption capacity of 258.39 mg g⁻¹ at 25 °C and pH 4, and a removal efficiency exceeding 99.55%. The adsorption kinetics followed a pseudo-second-order model, while intraparticle diffusion contributed to the rate-controlling mechanism, as indicated by the Weber–Morris model. OSP demonstrated excellent regeneration performance over five adsorption–desorption cycles, retaining more than 96% of its initial CR removal efficiency when regenerated with methanol. Grand Canonical Monte Carlo (GCMC) simulations revealed that adsorption is primarily driven by electrostatic interactions, hydrogen bonding, and π–π stacking interactions, in good agreement with the experimental findings. Overall, raw OSP represents an efficient, regenerable, and sustainable biosorbent, highlighting the originality of integrating experimental investigations with GCMC simulations for wastewater treatment applications. Full article

Background: Uropathogenic Escherichia coli (UPEC) is the primary etiological agent of urinary tract infections (UTIs) worldwide. The emergence of strains combining high virulence with multidrug resistance (MDR) poses a significant challenge to public health. This study aimed to characterize the phylogenetic distribution, virulence profiles, and antimicrobial susceptibility of UPEC isolates recovered from patients in the metropolitan area of Buenos Aires (AMBA), Argentina. Methodology: Phylogenetic groups, the ST131 lineage, and virulence-associated genes were identified using PCR-based assays. Antimicrobial susceptibility testing (AST) was performed using automated methods and extended-spectrum beta-lactamase (ESBL) production was confirmed using the double-disk synergy test. Colistin (COL) resistance was evaluated by Colistin Drop Test and PCR screening for the mcr-1 (mobile colistin resistance gene 1). Biofilm formation was detected by the Tissue Culture Plate (TCP) method, whereas phenotypic virulence factors (VF) were assessed with Congo Red agar, hemagglutination, and hemolysis assays. Results: Phylogenetic groups B2 (43.8%) and D (26.7%), typically associated with extraintestinal infections, were the most frequent. The high-risk clone B2-ST131 was detected in 6.7% of isolates. Biofilm production was observed in 92.4% of the isolates, with curli fimbriae (87.6%) being the most frequently expressed VF. The highest resistance rates were observed for ampicillin (62.1%), ampicillin-sulbactam (39.8%), and trimethoprim-sulfamethoxazole (25.2%). Interestingly, 3.8% of isolates exhibited colistin resistance, despite the absence of the mcr-1 gene. Conclusions: This study highlights the detection of MDR-UPEC isolates that showed strong resistance to fluoroquinolones and were ESBL producers with high virulence in Argentina, justifying future research encompassing genomic and epidemiological monitoring of local UPEC, which is essential for managing infections and developing new therapeutic and preventive measures. Full article

In this study, the in situ solvothermal synthesis of a copper-based metal–organic framework (Cu-BTC MOF) into two porous ceramic substrates with a 10 cm diameter and 2 cm thickness was reported. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, diffuse reflectance spectroscopy (DRS), Tauc plot analysis, optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were the techniques that were utilized to verify the formation and incorporation of the MOF into ceramics (two samples, with different SiO₂ particles; 500 µm (Ceramic 1), and 150 µm (Ceramic 2)). The synthesized Cu-MOF exhibited a crystalline structure. Both the composites and the Cu-MOF exhibited visible-light absorption, with optical band gaps of 2.5 eV and 2.4 eV, respectively, as determined by DRS. TEM images demonstrated that crystalline MOF domains were successfully included inside the ceramics. Methyl orange (MO), Congo red (CR), and methylene blue (MB) were used to assess the composites’ ability to remove dyes. Catalytic hydrogenation, powered by in situ hydrogen production from NaBH₄ hydrolysis, demonstrated high removal efficiencies of 91–97% after 60 min. Adsorption, on the other hand, was ineffective. Despite undergoing four consecutive cycles without performance degradation, the materials demonstrated remarkable recyclability. Cu-MOF@ceramic composites are effective, durable, and practically applicable for improved wastewater treatment. Full article

The escalating threat of antimicrobial resistance (AMR) and the environmental impact of industrial pollutants, particularly synthetic dyes, emphasize the pressing requirement for novel solutions. This study investigates the green synthesis of ZnO/Fe₂O₃ nanocomposites using Urtica dioica extract with the aim of achieving dual functionality as both antimicrobial agents and photocatalysts for pollutant degradation. The nanocomposites were synthesized with varying loads of Fe₂O₃ (5–50%) and characterized using X-ray diffraction (XRD) and diffuse reflectance spectroscopy (DRS). XRD analysis confirmed the presence of both the hexagonal wurtzite ZnO phase and the α-Fe₂O₃ hematite phase in all the composites, while DRS analysis revealed that the bandgap energy decreased progressively (from 1.89 to 1.72 eV) as the Fe₂O₃ content increased. The photocatalytic efficiency of the composites was evaluated by degrading methylene blue (MB), Congo Red (CR) and safranin O (SO) dyes under visible light. This demonstrated that the degradation performance depends on the composition, with the best activity being observed at 5% Fe₂O₃. Antioxidant activity was assessed using a DPPH• free radical scavenging assay. This showed that Urtica dioica extract exhibits superior radical scavenging capacity (maximum inhibition of 38%) compared to ZnO/Fe₂O₃ nanoparticles (maximum inhibition of 18%). The antibacterial efficacy against Pseudomonas aeruginosa was evaluated using direct confrontation and disk diffusion methods. This revealed that the activity was dose- and light-dependent, with enhanced performance under light exposure (10 mm inhibition zone) compared to dark conditions (1 mm). This study demonstrates the successful green synthesis of biphasic ZnO/Fe₂O₃ nanocomposites with promising photocatalytic and antimicrobial properties. While the results suggest possible synergistic interactions between the oxides, the underlying mechanisms, including potential charge transfer effects, require further investigation using advanced characterization techniques. Using Urtica dioica extract as a biogenic source provides a promising eco-friendly approach to synthesizing nanomaterials, with potential applications in wastewater treatment and the biomedical field. Full article

Three cerium-based metal–organic frameworks (MOFs), Ce-BDC, Ce-BDC-NH₂, and Ce-BTC, were used as catalysts for the hydroxylation of several organic compounds, including those not relevant to environmental or biological systems. Structural characteristics were validated by FT-IR spectroscopy, while SEM imaging demonstrated rod-like morphologies of 100–200 nm in width for Ce-BDC-NH₂ and 50–100 nm for Ce-BTC. The optical properties, ascertained using diffuse reflectance spectra and Tauc analysis, revealed bandgaps of 3.0 eV, 2.9 eV, and 3.6 eV for Ce-BDC, Ce-BDC-NH₂, and Ce-BTC, respectively. Catalytic investigations revealed that Ce-MOFs effectively convert phenol into 1,4-dihydroxybenzene with an efficiency of 86–99%, as confirmed by UV–Vis spectroscopy and HPLC analysis using an authentic hydroquinone (1,4-dihydroxybenzene) standard. The Ce-MOFs efficiently oxidize the dyes methylene blue (MB) and Congo red (CR) and also promote the hydroxylation of L-tyrosine, indicating their relevance to biologically significant substrates. The high catalytic performance of Ce-MOF highlights the potential of Ce-based materials for environmental remediation, chemical transformation, and sustainable wastewater treatment. Full article

A synergistic and magnetically recoverable NiFe₂O₄–MWCNT–CA nanocomposite was developed for efficient UV-driven photodegradation of hazardous organic pollutants. Biogenic NiFe₂O₄ nanoparticles synthesized using Costus speciosus extract exhibited a crystallite size of 32.5 nm, which increased to 83.6 nm upon incorporation into the MWCNT–cellulose acetate matrix. XRD confirmed the preservation of the cubic spinel structure, while VSM analysis showed maintained ferrimagnetic behavior with a saturation magnetization of 9.64 emu/g, enabling rapid magnetic separation. Although BET analysis revealed a reduction in surface area from 112.46 to 30.99 m²/g due to hybridization, the conductive MWCNT network significantly enhanced charge separation and interfacial electron transport. The composite displayed a widened optical bandgap of 5.3 eV, necessitating UV excitation for photocatalytic activity. Under UV irradiation, it achieved rapid degradation of methylene blue (97%) and Congo red (91%) at 20 mg/L, with corresponding rate constants of 0.119 and 0.076 min⁻¹. Scavenger experiments confirmed hydroxyl radicals (•OH) as the dominant reactive species, followed by photogenerated holes (h⁺). These results demonstrate a robust and synergistically engineered photocatalyst with high efficiency in removing organic pollutants under UV illumination. Full article

Paeoniae Radix Alba Carbonisata (PRAC), carbonized decoction pieces of the traditional Chinese medicine Paeoniae Radix Alba, has been used in clinical practice for hepatoprotective purposes. Hepatic amyloidosis (HA), a severe complication of systemic AA amyloidosis, is characterized by the deposition of fibrillar amyloid proteins leading to progressive hepatic dysfunction. However, its role in HA remains unclear. Amyloid lysozyme (LYSO-6) was used to induce the NCTC1469 cell injury model and the HA mouse model. The effects of PRAC extract (PRAC-E) on liver injury were then evaluated using biochemical assays, enzyme-linked immunosorbent assay (ELISA), Congo red (CR) staining, Hematoxylin and Eosin (H&E) staining, and immunohistochemical staining. Liver transcriptomics combined with Western blotting was used to analyze the expression levels of key proteins in the cGMP/PKG/ATP2A1 signaling axis. UHPLC-Q-Exactive Orbitrap MS combined with network pharmacology was used to characterize the chemical components of PRAC-E and identify its core active constituents against HA. Quantitative analysis of core components was performed by UHPLC-QTRAP-MS/MS. Molecular docking predicted the binding stability of core components and key targets. The results showed that PRAC-E significantly alleviated HA. Collectively, PRAC-E restored calcium pump activity, corrected calcium homeostasis imbalance, reduced inflammatory factor levels, regulated Phosphodiesterase 5A (PDE5A), and activated the cGMP/PKG/ATP2A1 signaling axis. The main components of PRAC-E were phenolic acids, terpenoids, and flavonoids. Among these, six core components (SCCs) related to HA were Gallate (16.96 mg/g), Paeoniflorin (14.27 mg/g), Albiflorin (7.20 mg/g), Benzoyl paeoniflorin (5.33 mg/g), Methyl gallate (0.78 mg/g), and Catechin (0.09 mg/g). Molecular docking analysis demonstrated that SCCs formed stable complexes (∆G ≤ −6.2 kcal/mol) with ATP2A1. Full article

Magnetic nanomaterials (MNMs) have been adopted as effective platforms for water remediation owing to their excellent surface-area-to-volume ratios, tunable surface chemistry, and magnetic separability. This review highlights the recent progress made in the synthesis, properties, and environmental applications in the removal of organic and inorganic contaminants using magnetic nanoparticles (MNPs) and one-dimensional magnetic nanofibers. Demonstrated removal rates of organic contaminants such as dyes, pharmaceuticals, and pesticides are often up to 85–100% under laboratory conditions, with adsorption capacities of 580 mg·g⁻¹ for melanoidin, 397.43 mg·g⁻¹ for Congo Red, and 392.64 mg·g⁻¹ for tetracycline. For heavy metals such as As(V), Cd(II), Cr(VI) and Pb(II), efficiencies are generally between 90–99% with maximum adsorption capacities of 909.1 mg·g⁻¹ for Pb(II). In particular, the review compares major synthesis routes such as coprecipitation, hydrothermal, solvothermal, thermal decomposition, sol–gel, microwave, and green methods by evaluating their effect on particle size (6–50 nm), magnetic properties (saturation magnetization up to ~101 emu·g⁻¹), and removal performance. The four principal mechanisms are described in this paper—adsorption, filtration, transformation, and photocatalysis—giving special emphasis to the advantages of magnetic recovery and advanced oxidation processes. Although most studies remain at the laboratory scale, MNMs demonstrate strong potential for scalable wastewater treatment, provided that toxicity, life-cycle impacts, and matrix effects are carefully evaluated. Full article

Background: Amyloidosis involving the heart is one of the types of the disease recognized in humans and has been previously described in dogs. To date, no data regarding the presence of amyloid in cardiac tissues of a large group of feline patients have been published. Our research aimed to analyze the presence and localization of amyloid in the atrial and ventricular cardiac tissue in retrospectively enrolled cats diagnosed with various types of primary cardiomyopathies, hyperthyroidism-induced cardiomyopathy, myocarditis, and generalized disorders. Methods: This study was conducted on atrial specimens obtained from 119 animals and on ventricular specimens obtained from 69 animals from that group. The atrial and ventricular specimens obtained from the enrolled animals were stained with Congo Red and evaluated in a light microscope and polarized light for the presence of amyloid deposits. Results: Five cases from the enrolled group turned out positive for amyloid deposits: three cats diagnosed with feline hyperthyroidism, one cat diagnosed with kidney glomerulonephritis, and one cat diagnosed with restrictive cardiomyopathy. In all positive cats, the amyloid deposits were present within the small intramural coronary arteries of the left ventricular free wall and interventricular septum and/or left and right atrium. No myocardial amyloid deposits were identified in the study group. Conclusions: In conclusion, cardiac coronary arterial amyloidosis, although infrequent, can be observed in cats. Full article

Background: Healthcare-associated infections (HAIs) caused by biofilm-forming Staphylococcus aureus and Staphylococcus epidermidis represent a major public health challenge due to their high resistance and involvement in skin, wound, and soft-tissue infections. In this context, silver nanoparticles (AgNPs) incorporated into Gluconacetobacter sp. bacterial cellulose hydrogel emerge as a promising alternative therapeutic strategy. Methods: AgNPs and hydrogels were synthesized and characterized using physicochemical and morphological analyses. Antibacterial activity was assessed by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) following CLSI guidelines, as well as by time–kill curve assays. Antibiofilm activity was evaluated through the determination of minimum biofilm inhibitory concentration (MBIC) and minimum biofilm eradication concentration (MBEC) using crystal violet staining, complemented by scanning electron microscopy (SEM) and Congo red agar method. Results: The hydrogel exhibited a three-dimensional microfibrillar structure characteristic of bacterial cellulose, while AgNPs showed rod-shaped, oval, and triangular morphologies, with particle sizes of 35 and 59 nm and positive zeta potentials. MIC and MBC values ranged from 6.25 to 50 µg/mL across all tested formulations and strains. Time–kill assays demonstrated significant bacterial population reductions after 6 to 9 h of exposure. MBIC values ranged from 0.78 to 50 µg/mL, whereas MBEC values ranged from 1.56 to >100 µg/mL. SEM analyses confirmed biofilm disruption, cell eradication, and a reduction in extracellular polysaccharides, particularly for AgNPs incorporated into the hydrogel. Conclusions: Overall, the results highlight the strong antibacterial and enhanced antibiofilm potential of AgNP-loaded bacterial cellulose hydrogel against S. aureus and S. epidermidis, supporting its potential application in infection treatment. Full article

Colletotrichum fructicola is the predominant pathogenic agent responsible for anthracnose in Camellia oleifera. RGS2 is a GTPase-activating protein that negatively regulates G-protein signaling by inactivating Gα subunits. In this study, we characterized the ortholog of CfRGS2 in C. fructicola to explore its pathogenic roles. Seven canonical RGS genes were identified through BLASTp and keyword searches. Conserved domains and subcellular localizations were predicted bioinformatically. A CfRGS2 knockout mutant was generated via overlap-PCR and PEG-mediated transformation, verified by PCR, and complemented by reintroducing the wild-type gene. Phenotypic characterization showed that the growth rates of mutants ΔCfrgs2-1 and ΔCfrgs2-2 were significantly reduced compared with those of the wild-type and complemented strains. On both PDA and minimal medium, the mutant strains exhibited significantly smaller colony diameters of 3.3 cm and 3.1 cm, respectively, relative to the control strains. Moreover, conidiation in the mutants was only 4% of that in the wild-type and complemented strains, and appressorium formation was reduced to 6%, with statistical analyses confirming high significance. Under cell wall stress induced by 400 μg/mL Congo red, the growth inhibition rates of ΔCfrgs2-1 and ΔCfrgs2-2 were 44% and 48%, respectively, significantly higher than those of the control strains. Pathogenicity assays demonstrated that the mutants failed to induce lesions on unwounded leaves and caused 47% and 30% smaller lesion areas on wounded apple fruits, respectively. In summary, C. fructicola possesses seven canonical RGS proteins that regulate G-protein signaling, among which CfRgs2 is implicated in growth, conidiation, the stress response to cell wall perturbation, and virulence. Full article