Search Results (467)

Two heteroaromatic hybrid compounds were synthesized and characterized using various analytical techniques. The results indicate that the benzimidazole/oxadiazole (BZ/OZ) metal derivative exhibits a tridentate coordination mode, where the carbonyl, imidazole and oxadiazole groups participate in coordination with the metal, in a ratio of 2:1 of the ligand to the metal. The antibacterial activities of the organic ligand and its metal complex were determined by in vitro tests against both Gram-positive bacterial strains and Gram-negative bacterial strains using the broth microdilution method. The metal complex showed greater antibacterial activities compared to the precursor ligand against all evaluated microorganisms. The results obtained through in silico predictions revealed significant toxicological differences among the analyzed molecules, suggesting special attention in the use of the ligand due to its possible carcinogenicity in mice and a need for structural modifications in the complex to reduce its carcinogenicity and toxicity. Furthermore, a biophysical study of the interaction of the BZ/OZ derivatives with different model membranes was explored through differential scanning calorimetry (DSC), simultaneous small- and wide-angle X-ray diffraction (SAXD and WAXD) and infrared spectroscopy (FT-IR). The results indicate that the compounds influenced membrane properties without significantly altering the lamellar organization. The findings suggest potential applications in understanding lipid interactions, elucidating toxicology and developing antibacterial agents. Full article

This study aimed to investigate the phytochemical constituents of C. odorata leaves and stems and to evaluate their antioxidant, total phenol, α-glucosidase, and antibacterial activities. Furthermore, liquid chromatography-high-resolution mass spectrometry (LC–HRMS)-based metabolite profiling combined with principal component analysis (PCA) was applied to correlate metabolite composition with functional activities, providing comprehensive insights into the metabolomic diversity and bioactive differentiation between plant parts. The plant materials were extracted using 70% and 100% ethanol for 24 h. The leaf extract of ethanol 70% (EtOH 70) exhibited the highest antioxidant activity (IC₅₀ of 223.33 ± 9.20 µg/mL) and total phenolic content (113.15 mg GAE/g), while the stem EtOH 70% extract showed the strongest antidiabetic activity through α-glucosidase inhibitory activity (78.57%). Although appearing less potent, all extracts showed dose-dependent inhibitory activity, such as Staphylococcus aureus (highest value at 9.31 mm), Escherichia coli (highest value at 9.92 mm), and Salmonella typhimurium (highest value at 9.00 mm). Comparing the plant parts, leaf extracts generally showed more potent activity than stem extracts, particularly evident against E. coli (e.g., Leaf EtOH 70% at 5 mg/mL: 9.92 mm vs. Stem EtOH 70%: 7.97 mm). LC-HRMS analysis revealed the presence of phenolics, flavonoids, amino acids, organic acids, and alkaloids. Furthermore, the result indicates that C. odorata is a rich source of bioactive compounds with significant antioxidant, α-glucosidase inhibitory, and antibacterial potency. The findings advance existing knowledge beyond earlier phytochemical or single-activity studies, offering a more holistic understanding of C. odorata’s therapeutic potential and its relevance for natural product development. Full article

This study investigates the influence of laser processing parameters on the surface roughness and color formation of AISI 304 stainless steel. Experiments were conducted to explore how raster step, scanning speed, frequency, linear energy density, and overlap coefficient affect the surface characteristics of laser-marked zones. It was found that increasing the raster step from 20 µm to 80 µm led to a consistent increase in surface roughness (from 1.23 µm to 1.47 µm at 20 kHz and 25 mm/s), accompanied by a shift in color from dark brown to lighter yellow hues. In contrast, increasing scanning speed (from 25 mm/s to 125 mm/s) caused a nonlinear reduction in roughness (e.g., from 1.23 µm to 0.76 µm at 20 kHz and Δx = 20 µm), resulting in a lighter surface color. Frequency was identified as a critical factor; increasing it from 20 kHz to 100 kHz resulted in a threefold decrease in roughness (from 1.23 µm to 0.25 µm at 20 µm raster step and 125 mm/s), which correlated with a shift to brighter yellow tones. Higher linear energy density values (1.60–8.00 J/cm) increased roughness and darkened the surface color, while higher overlap coefficients produced the opposite trend. The study highlights the relationship between surface nanostructuring and the formation of stable interference colors, providing quantitative parameters for achieving desired chromatic effects. These findings establish a basis for the industrial application of laser color marking, where both aesthetic differentiation and functional enhancements—such as corrosion resistance, hydrophobicity, and antibacterial properties—are essential. Future research will focus on quantitatively evaluating the functional properties, including corrosion resistance, hydrophobicity, and durability, of the colored surfaces produced under optimized parameters. This research aims to further develop laser marking as a foundational tool for both aesthetic and functional surface engineering. Full article

Listeria monocytogenes and Salmonella enterica Typhimurium are leading causes of foodborne illness in the United States and frequently implicated in produce outbreaks. Conventional decontamination methods, such as cold-water washes with chlorine, have limited antibacterial efficacy and environmental sustainability. Power ultrasound has emerged as a promising non-thermal alternative, but the molecular mechanisms remain insufficiently elucidated. This study evaluated transcriptomic responses of L. monocytogenes and S. enterica Typhimurium to (i) ultrasound (20 kHz), (ii) chlorine (50 ppm), and (iii) combined ultrasound + chlorine treatments. RNA-seq analysis identified differentially expressed genes, as well as enriched Gene Ontology and KEGG terms. Results showed that ultrasound and chlorine triggered distinct transcriptomic responses. L. monocytogenes exhibited broad transcriptional shifts under ultrasound, including significant upregulation of phosphotransferase system components and central metabolism. Chlorine alone induced a narrower response, with fewer differentially expressed genes clustering into limited functional categories. In contrast, the combined ultrasound + chlorine treatment elicited the strongest response in S. enterica Typhimurium, with enrichment of multiple energy- and metabolism-related pathways, including the citrate cycle, carbon metabolism, and microbial metabolism in diverse environments. These findings provide new insights into ultrasound-triggered responses in foodborne pathogens and may inform development of optimized ultrasound-based hurdle sanitization strategies for produce safety. Full article

This research investigated the sustainable biosynthesis of silver nanoparticles (AgNPs) using Zinnia elegans L. extracts to demonstrate the potential of plant-based methods in nanotechnology. The antioxidant and antibacterial properties of the plant extracts were evaluated, and the phytocompounds that react as natural reducing agents in the synthesis of AgNPs were characterized. This approach has demonstrated the potential of Zinnia elegans L. as an environmentally friendly source for the production of AgNPs. The biosynthesized AgNPs were characterized based on their optical, structural, and morphological properties using various techniques, including scanning electron microscopy (SEM), attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR), and thermogravimetric and differential thermal analysis (TGA/DTA). X-ray diffraction (XRD) analysis confirmed the presence of pure silver phases exhibiting a face-centered cubic (FCC) crystalline structure. Ultraviolet–visible (UV–Vis) spectroscopy revealed an absorption peak at 462 nm, which is characteristic of the surface plasmon resonance associated with AgNPs. ATR-FTIR analysis identified several vibrational peaks corresponding to the functional groups of the constituents present in the biosynthesized AgNPs. The size distribution of the AgNPs was found to range from 10 to 30 nm, and both SEM and TEM confirmed their predominantly spherical morphology. Energy dispersive X-ray spectroscopy (EDX) analysis corroborated the predominance of silver as the principal element within the composition of the nanoparticles. This technique provided quantitative elemental analysis, confirming the high purity and concentration of silver in the synthesized AgNPs. The study effectively elucidated the synthesis of AgNPs utilizing plant extracts as natural reducing agents. The synthesized AgNPs exhibited significant antibacterial and antioxidant activities, indicating their potential applicability in diverse biomedical and environmental contexts. Employment of the advanced characterization techniques facilitated a thorough understanding of the multifaceted properties of the synthesized AgNPs, thereby enhancing their viability for future research and application in nanomedicine and bioremediation. Using Zinnia elegans L. for the biosynthesis of plant-synthesized AgNPs is a sustainable and eco-friendly technique that offers a viable alternative to conventional chemical processes. Full article

Fluctuating water temperatures and bacterial pathogens such as Edwardsiella tarda pose a serious threat to mariculture, resulting in significant economic losses within the flounder industry. A previous study revealed that elevated temperature enhanced E. tarda dissemination in flounder tissues. However, the underlying mechanism has not been fully explained, especially the changes in protein level. In this study, label-free proteomics was utilized to investigate the impact of high temperature (23 °C) and low temperature (15 °C) on flounder immune response to E. tarda infection. Our results identified 317 differentially abundant proteins (DAPs) in the low-temperature group (LI-LC) and 302 DAPs in the high-temperature group (HI-HC). GO and KEGG analyses of DAPs revealed numerous immune-related proteins and pathways. Twenty-six key DAPs in the LI-LC group and twenty-seven key DAPs in the HI-HC group were further identified and formed extensive interaction networks, respectively. Through the analysis of key immune-related DAPs that were specifically identified in both groups via Venn diagram analysis, we demonstrated that the endocytosis capacity and complement activity were enhanced in the HI-HC group, while histone abundance and RNA transport function were, respectively, increased and severely interfered with in the LI-LC group. These findings highlight a clear divergence in the immune response of flounder to E. tarda infection between 15 °C and 23 °C, providing valuable insights into how temperature variation influences antibacterial immunity in fish. Full article

High-throughput sequencing has significantly advanced the exploration of fish immune mechanisms, enabling a more detailed understanding of immune responses and their underlying molecular pathways. In this study, we applied comparative transcriptomics and single-cell RNA sequencing to investigate the immune mechanisms of tilapia in response to different pathogenic bacteria. Our results demonstrated that nonspecific cytotoxic cells (NCCs) and monocytes/macrophages (Mos/Mφs) mounted the most pronounced responses to both Streptococcus agalactiae and Aeromonas hydrophila infections. Moreover, Mos/Mφs exhibited distinct differentiation patterns depending on the bacterial challenge. Collectively, these findings offer new insights into the antibacterial immune strategies of lower vertebrates. Full article

The increasing demand for sustainable alternatives to non-biodegradable plastic packaging is driving the development of active packaging based on biopolymers such as methylcellulose. In this study, innovative methylcellulose nanocomposite films incorporating zein nanoparticles loaded with propolis and curcumin were developed for active packaging applications. The zein nanoparticles revealed excellent physicochemical properties, with a zeta potential above 30 mV, suggesting adequate stability. Transmission electron microscopy confirmed nanoparticles containing curcumin and propolis with uniform sizes ranging from approximately 130 to 140 nm with low polydispersity. Release studies revealed that approximately 25% of the curcumin and 35% of the propolis were released from the nanoparticles within 24 h. The release mechanism was best described by the Korsmeyer–Peppas model, suggesting a sustained release profile. The nanoparticles reduced the hydrophobicity and rigidity of the films, as evidenced by a lower elastic modulus and higher percentage elongation, thereby suggesting greater flexibility. Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed the incorporation of bioactive compounds in the polymer matrix. Differential scanning calorimetry (DSC) revealed the thermal parameters of the synthesized films. Furthermore, the films exhibited antibacterial and antioxidant activities, making them highly suitable for use as biodegradable active packaging. Full article

Chitosan-based nanoparticles were prepared using an eco-friendly chemical procedure that conjugates natural fatty acids to the backbone of chitosan. This consists of reacting two molecules in the absence of a solvent and using microwaves to promote the chemical transformation. Both conditions make the whole chemical process more eco-compatible in terms of reagents and energy consumption. The chemical structure and the self-association behavior of chitosan–fatty acid conjugates were characterized by FT-IR, NMR, and dynamic light scattering. The conjugates displayed an enhanced solubility and efficient self-assembly in aqueous solution. The antimicrobial activity of the resulting nanoparticles was evaluated against Escherichia coli (Gram-negative) and Bacillus subtilis (Gram-positive). The micelles significantly inhibited E. coli growth (35–60%), even at relatively low concentrations, whereas negligible activity was observed against B. subtilis. The antibacterial efficacy appears to arise primarily from the ability of the developed nanostructured conjugates to perturb bacterial membranes. These results support the potential of chitosan–fatty acid conjugates as sustainable nanomaterials for biomedical applications, particularly as eco-friendly antimicrobial agents. Future work will evaluate their activity against other Gram-positive pathogens and explore their use in drug delivery. Full article

Novel multifunctional fibrous materials were prepared by simultaneous dual spinneret electrospinning of two separate solutions differing in composition. This technique allowed for the preparation of materials built of two types of fibers: fibers from poly(vinyl alcohol) (PVA), chitosan (Ch), and rosmarinic acid (RA), and poly(L-lactide) (PLA) fibers containing lidocaine hydrochloride (LHC). Confocal laser scanning microscopy (CLSM) analyses showed that both types of fibers are present on the surface and in the bulk of the new materials. The presence of all components and some interactions between them were proven by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. RA and LHC were in an amorphous state in the fibers, and their presence affected the temperature characteristics and the crystallinity, as detected by differential scanning calorimetry (DSC) and X-ray diffraction analyses (XRD). The presence of PVA/Ch/RA fibers enabled the hydrophilization of the surface of the multifunctional fibrous materials (the water contact angle value was 0°). The newly developed materials demonstrated adequate mechanical properties, making them suitable for use in wound dressing applications. The RA-containing fibrous mats possessed high radical-scavenging activity (ca. 93%), and the combining with LHC led to an enhancement of this effect (ca. 98.5%). RA-containing fibrous mats killed all the pathogenic bacteria S. aureus and E. coli and decreased the titer of fungi C. albicans by ca. 0.4 log for a contact time of 24 h. Therefore, the new materials are prospective as antibacterial and atraumatic functional wound dressings, as systems for local drug delivery, and in medical skincare. Full article

The logistic modeling of diauxic growth and biphasic antibacterial activity (AA) production was enhanced for four lactic acid bacteria (Lactococcus lactis CECT 539, Pediococcus acidilactici NRRL B-5627, Lactobacillus casei CECT 4043, and Enterococcus faecium CECT 410) during realkalized fed-batch fermentations. The improved growth model, also validated for describing the diauxic growth of Mos breed roosters and foals, overcomes a key limitation of the bi-logistic model, which assumes the existence of two distinct populations growing from the start of the culture, each following a different growth profile. In contrast, the improved logistic growth model developed in this study accounts for a single population growing at two rates, offering a fit to the experimental data comparable to that of the commonly used bi-logistic model. The enhanced model for product synthesis accurately describes biphasic AA production, assuming that antibacterial products are synthesized as growth-associated metabolites, depending on the final pH reached in the cultures at each sampling time. Additionally, it is easier to apply than the unmodified or modified differential forms of the Luedeking–Piret model. This study demonstrated, for the first time, the applicability of these two models in describing the diauxic growth and biphasic AA synthesis of LAB. Full article

Background: The rapid emergence of antibiotic resistance in Acinetobacter baumannii has led the World Health Organization (WHO) to designate it as a “high priority” pathogen. The emergence of multidrug-resistant (MDR) and pandrug-resistant (PDR) strains poses considerable treatment challenges. As antimicrobial resistance (AMR) escalates toward a post-antibiotic era, innovative therapeutic solutions are urgently needed. Objectives: To clone, over-express, and characterize a novel endolysin, LysTAC1, from Acinetobacter phage TAC1 for its antibacterial efficacy against multidrug-resistant bacteria. Methods: A 24 kDa endolysin featuring a glycoside hydrolase Family 19 chitinase domain was tested against carbapenem-resistant Acinetobacter baumannii clinical isolates and various Escherichia coli strains following outer membrane permeabilization with Ethylenediaminetetraacetic acid (EDTA). Stability assays and molecular docking studies were performed. Results: LysTAC1 demonstrated potent lytic activity against Gram-negative bacteria but showed no activity against Gram-positive bacteria (Staphylococcus aureus ATCC 29213 and Enterococcus gallinarum HCD 28-1). LysTAC1 maintained activity across pH 6–9 and temperatures 4–65 °C, with differential sensitivity to metal ions where K⁺ showed no inhibitory effect at any concentration (0.1–100 mM), and Fe²⁺ was non-inhibitory at lower concentrations (0.1–1 mM), while Mg²⁺ and Ca²⁺ demonstrated concentration-dependent inhibition across the tested range (0.1–100 mM). Molecular docking revealed LysTAC1 interactions with chitinase substrates 4-nitrophenyl N-acetyl-β-D-glucosaminide and 4-nitrophenyl N, N-Diacetyl-β-D-chitobioside, with binding energies of −5.82 and −6.85 kcal/mol, respectively. Conclusions: LysTAC1 shows significant potential as a targeted therapeutic agent against A. baumannii with robust stability under physiological conditions. Full article

Background/Objectives: Over the past twenty years, there has been a rapid increase in studies aimed at comprehending how cells communicate with each other via Extracellular Vesicles (EVs), accompanied by a heightened interest in plant-derived extracellular vesicles due to their potential relevance in dietary supplementation and therapeutic applications. However, there is a limited amount of research on extracellular vesicles derived from mushrooms (MDEVs). Among edible mushrooms, Pleurotus eryngii is peculiar due to its flavor and interesting nutritional profiling. It also produces a wide array of secondary metabolites including biologically active compounds with many health-promoting benefits such as anticancer, antioxidant, antitumor, antiviral, antibacterial, antidiabetic, and anti-hypercholesteremic activities. The aim of this work has been to isolate EVs from the fruiting body and mycelium of P. eryngii in order to investigate their potential applications as nutraceuticals. Methods: MDEVs were isolated by differential and density gradient centrifugation, characterized by Nanoparticle Tracking Analysis (NTA), Scanning Electron Microscopy (SEM) and immunoblotting, and subjected to metabolomic and phenolic profiling. Their antioxidant potential was assessed through in vitro radical scavenging (DPPH, ABTS) and metal-reducing (CUPRAC, FRAP) assays. Results: The findings suggest that mycelium-derived EVs may represent a valuable source of high-quality MDEVs, which exhibited promising antioxidant properties in all assays conducted, particularly in radical scavenging assays. Conclusions: These results highlight the potential of P. eryngii mycelium-derived EVs as a novel natural source of bioactive compounds, paving the way for future applications in nutraceutical and therapeutic fields. Full article

Background/Objectives: This study investigates the antimicrobial properties of pomegranate peel extract (PoPEx) and its major polyphenolic constituents against Gram-positive and Gram-negative bacteria, employing six clinical isolates of Staphylococcus aureus and five isolates of Escherichia coli. The study further aims to elucidate mechanisms of action through molecular docking and transport studies. Methods: Chemical composition was analyzed using liquid chromatography–mass spectrometry (LC–MS). Antimicrobial activity was determined by the broth microdilution method. Molecular docking was performed with the AutoDock Vina algorithm, and transport studies through porin channels were carried out using Caver software. Results: PoPEx showed stronger activity against Gram-positive (MICs 15.62–500.00 μg/mL) than Gram-negative bacteria (MICs 125.00–500.00 μg/mL). Punicalagin was most active against S. aureus, while gallic acid was most effective against E. coli. Docking revealed high affinities of punicalagin and punicalin, whereas transport studies highlighted the advantage of smaller phenolics like gallic acid in crossing porins. Conclusions: Larger tannins exhibited strong target binding but limited porin permeability, reducing efficacy in Gram-negative bacteria. These findings provide insights into structure–activity relationships of pomegranate polyphenols and support their potential as natural antimicrobial agents. Full article

This study explored the synthesis and characterization of pectin-based composites containing encapsulated propolis and sea buckthorn oil. Both propolis and sea buckthorn oil are well known for their antioxidant and antimicrobial properties. To mitigate their sensitivity to environmental degradation, these compounds were encapsulated within a pectin matrix. The composites were prepared using an emulsification technique and subsequently for their physicochemical properties via scanning electron microscopy (SEM), ultraviolet–visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC), as well as color and mechanical testing. The results showed that freeze-dried samples exhibited heterogeneous, bubble-like structures containing nanocapsules (800–2000 nm), whereas for the film samples, the capsules were visibly embedded within the matrix. The study shows that this three-component system exhibits synergistic potential. Encapsulation significantly improved the UV barrier properties and the antioxidant activity of the nanocomposites, which demonstrated greater antioxidant capacity. Microbiological assays revealed that the pectin-based composites containing encapsulated propolis and sea buckthorn oil exhibited strong antibacterial activity, particularly against Gram-positive bacteria such as Streptococcus and Staphylococcus spp. The composites also demonstrated hydrophobic surface characteristics and reduced crystallinity, which correlates with their potential for controlled release. These results underscore the applicability of pectin–propolis–sea buckthorn oil composites as effective natural preservatives or functional ingredients in food systems, due to their high antioxidant and antimicrobial efficacy. Full article