Search Results (5,078)

Brucellosis, acting as a typical chronic zoonotic disease, is caused by the invasion of Brucella into the human body. Outer membrane protein 25 (Omp25), specifically localized on the Brucella membrane, is the main virulence factor of Brucella and participates in multiple links of the damage process. Omp25c, a porin protein of Brucella, is a paralog of Omp25 with high sequence identity. NADH dehydrogenase [ubiquinone] complex I assembly factor 2 (Ndufaf2) has a key function in cell energy metabolism, particularly in the formation and activity of the mitochondrial respiratory chain. Loss of Ndufaf2 results in oxidative stress and mitochondrial DNA (mtDNA) deletion. However, the functional relationship between Omp25c and Ndufaf2, the underlying mechanism of the proteins, remains unclear. In this work, we purified the Omp25c and Ndufaf2proteins. Our data revealed that Omp25c directly interacts with Ndufaf2, as determined using Biacore analysis. In addition, assays revealed that Ompa2c reshapes the host cell’s redox environment by decreasing the oxidized nicotinamide adenine dinucleotide/reduced nicotinamide adenine dinucleotide (NAD⁺/NADH) ratioand adenosine triphosphate (ATP) production, whereas Ndufaf2 exerts an opposing regulatory effect; Co-expression results further revealed an antagonistic relationship between the two during metabolic processes. These findings provide a new perspective for elucidating the mechanisms of mitochondrial functional regulation in Brucella–host interactions and lay the theoretical and experimental foundation for drug development targeting metabolic interventions to eliminate intracellular pathogens. Full article

Colorectal cancer (CRC) is the third most prevalent cancer globally. TASK-1, encoded by the KCNK3 gene, is emerging as a putative target in cancer; it regulates resting membrane potential, cell proliferation, and apoptosis. A series of 27 novel xanthene derivatives, modified at position 9, were synthesized via azide coupling of 2-(9H-xanthen-9-yl)acetohydrazide with selected amines and amino acids, followed by hydrazine-mediated conversion to the corresponding hydrazides. The cytotoxic activity of selected compounds (5a–5g, 6a–6h, 7b, 7f–7h) was evaluated against the HCT-116 cell line in vitro. In addition, molecular docking and molecular dynamics simulations were performed to investigate binding interactions and assess the stability of the protein–ligand complexes. Several compounds (5f, 5g, 6c, 6d, 6f, 6g, 7b, 7f, and 7h) exhibited moderate cytotoxic activity against HCT-116 cells (IC₅₀: 66.97–99.62 µM), compared to cisplatin (IC₅₀: 18.25 µM). Compound 7h demonstrated pronounced antiproliferative effects, evidenced by DAPI staining showing chromatin condensation and apoptotic body formation, along with a marked reduction in cell count and coverage. Molecular docking indicated favorable binding within the TASK-1 potassium channel, and molecular dynamics simulations confirmed the stability of the protein–ligand complex, with consistent interactions, including a key hydrogen bond with Asn240. These findings support 7h as a promising lead candidate. These findings identify xanthene-based derivatives as promising lead compounds for further optimization as TASK-1-targeted therapeutic candidates in colorectal cancer Full article

The growing problem of antibiotic resistance poses a serious threat to public health and ecosystems. New disinfection methods could help address this global issue. In this study, ultraviolet-C light-emitting diodes (UV-C LEDs) were used to inactivate Escherichia coli isolates resistant to antibiotics. These isolates were obtained from various real water sources, including seawater, surface water, and treated wastewater. Inactivation assays were performed using two wavelengths (255 nm and 265 nm), applying UV fluences ranging from 1 to 7 mJ/cm² to a phosphate-buffered saline solution inoculated with a mixture of 10 E. coli strains. Using an UV fluence of 2 mJ/cm², a log reduction of about 5 was achieved with both UV-C wavelengths tested. SEM imaging revealed no observable alterations in cell morphology after UV-C exposure. Pyrimidine dimer formation was quantified, yielding approximately 40 ng/mL of cyclobutane pyrimidine dimers after 2 mJ/cm² of exposure to both wavelengths. Additionally, water treatment was tested using ceramic silicon carbide membranes. High average rejection efficiencies (99.9%) were obtained for both total coliforms and E. coli using uncut flat sheet membranes. The combination with UV-C LEDs led to treatment of the concentrated membrane retentate (99.985% or higher), highlighting the potential of this treatment approach for effective water disinfection. Full article

Mitochondrial dysfunction is a relevant hallmark of Alzheimer’s disease (AD), contributing to the impaired metabolic homeostasis involved in neuronal loss and cognitive decline. In this study, we target the metabolic dysfunction occurring in AD through a novel pharmacological approach involving the modulation of glutamate dehydrogenase (GDH), which converts glutamate to α-ketoglutarate and supports the tricarboxylic acid (TCA) cycle. In our experimental models (i.e., differentiated SH-SY5Y cells and primary rat cortical neurons exposed to glyceraldehyde and amyloid-beta peptide 1-42, respectively), the allosteric GDH activator 2-Aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH) increased mitochondrial ATP production, improved cellular bioenergetics, and reduced oxidative stress, ultimately promoting neuronal survival. Ionic dysfunctions in AD are linked to disrupted calcium homeostasis and organelle storing properties. In this context, GDH activation potentiated mitochondrial and endoplasmic reticulum calcium buffering capacity by enhancing store-operated calcium entry. Oxidative stress, largely driven by mitochondrial ROS overproduction, represents another major contributor to AD pathology. In our AD models BCH-mediated GDH activation reduced ROS formation and restored mitochondrial membrane potential (ΔΨ_m). Importantly, these metabolic and ionic improvements were associated with decreased accumulation of amyloid-β (Aβ_1-42) and phosphorylated tau (pTau), two key AD biomarkers. Overall, modulation of the GDH/TCA pathway represents a promising approach for restoring metabolic dysfunctions and counteracting oxidative stress and ionic dysregulation and therefore AD neurodegeneration. Full article

Colletotrichum species are among the most destructive phytopathogens worldwide, with appressorium-mediated penetration representing a critical stage in host infection. Targeting this morphogenetic transition offers a promising strategy for sustainable disease control by interfering with the infection process rather than solely inhibiting fungal growth. In this study, chitosan–κ-carrageenan nanoparticles (CS–κ-CRG) without and with lysozyme (CS–κ-CRG/Lz) were synthesized, characterized, and evaluated for their ability to inhibit appressorium formation in Colletotrichum siamense, a strain exhibiting low sensitivity to chitosan. The nanoparticles showed monodisperse size distributions, with hydrodynamic diameters of 503 and 333 nm for CS–κ-CRG and CS–κ-CRG/Lz, respectively, positive surface charges of approximately +26 mV, spherical morphology, and a lysozyme encapsulation efficiency of 63%. Both formulations significantly reduced conidial viability and delayed germination, inducing morphological alterations such as conidial swelling, hyphal deformation, and vacuolization. Fluorescence microscopy using calcofluor white and propidium iodide revealed disturbances in cell wall organization and loss of membrane integrity. Both nanomaterials markedly affected appressorium development in a concentration- and formulation-dependent manner. Notably, CS–κ-CRG/Lz showed stronger suppression of appressorium formation, whereas at 200 µg·mL⁻¹, CS–κ-CRG nanoparticles stimulated appressorium formation, suggesting that sublethal nanoparticle stress may trigger compensatory or hyper-pathogenic responses. These findings highlight the potential and complexity of utilizing chitosan-based nanomaterials for phytopathogen management and emphasize the importance of mechanistic and dose–response evaluations before field application. Full article

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains a major cause of morbidity and mortality worldwide, particularly due to the emergence of drug-resistant strains. Membrane-active antimicrobial peptides (AMPs) represent attractive therapeutic candidates because they target bacterial envelope integrity and disrupt essential cellular processes. We evaluated two rationally designed LL-37-derived peptides: a truncated C-terminally amidated analog (LL37-1) and a modified variant incorporating N-terminal acetylation and a single D-amino acid substitution (D-LL37). Dose–response analysis demonstrated that D-LL37 exhibited greater antimycobacterial potency, with lower inhibitory concentrations of 90% (IC₉₀) and 50% (IC₅₀) values (18.40 ± 0.39 μM and 10.11 ± 0.60 μM, respectively) compared with LL37-1 (25.44 ± 0.36 μM and 15.45 ± 1.40 μM). Fluorescence-based permeability assays revealed partial membrane disruption (36% and 44% at IC₉₀ for LL37-1 and D-LL37, respectively), which was supported by ultrastructural alterations observed by scanning electron microscopy, including bacillary shortening, rough surface formation, cell clusters, and the presence of cellular debris, all of which are consistent with membrane damage. RT-qPCR analysis demonstrated significant upregulation of the P-type ATPase genes ctpF, ctpA, and ctpH following D-LL37 exposure. Collectively, these findings indicate that optimized LL-37-derived peptides exert antitubercular activity associated with envelope perturbation and coordinated activation of ion transport-related stress responses. Full article

The differentiation of dental papilla cells (DPCs) into functional odontoblasts is critical for dentinogenesis, yet the role of mitochondrial dynamics remains unclear. Here, we investigated the functional role of mitochondrial fission and mitochondria-associated endoplasmic reticulum membranes (MAMs) in the odontogenic differentiation of DPCs. Using in vitro differentiation models combined with confocal microscopy, transmission electron microscopy, and gain- and loss-of-function approaches, we found that odontogenic induction triggered early mitochondrial fragmentation and increased MAM formation. Dynamin-related protein 1 (DRP1) mediated mitochondrial fission, which in turn regulated MAM architecture and promoted differentiation. Malic enzyme 2 (ME2) acted as an upstream regulator, facilitating DRP1 recruitment and organizing MAM integrity. Notably, disruption of the ME2-DRP1-MAM axis impaired dentin formation both in vitro and in vivo, either by ME2 knockdown or pharmacological inhibition of DRP1 (Mdivi-1). These findings establish the ME2-DRP1-MAM axis as a critical metabolic–organellar switch driving odontoblast differentiation, providing new mechanistic insights into dentinogenesis and identifying potential therapeutic targets for dentin–pulp complex regeneration. Full article

Developing membranes with superior antifouling properties is crucial for efficient and sustainable water treatment. In this study, polysulfone (PSM) composite membranes were fabricated by incorporating hydroxylated titanium nanotubes (TNT@OH) via the non-solvent-induced phase separation method. The hydroxylation of TNTs enhanced their dispersion in the polymer matrix and promoted strong polymer–nanoparticle interactions. Comprehensive characterization using FTIR, XRD, TGA, FESEM, and AFM confirmed the successful integration of TNT@OH, resulting in membranes with improved hydrophilicity, porosity, and thermal stability. The contact angle decreased from ~88° for neat PSM to ~50° at 7 wt% TNT@OH, while surface free energy increased significantly. Mechanical strength and flexibility were also enhanced at optimal TNT@OH loadings (3–5 wt%), owing to uniform dispersion and strong interfacial bonding. Filtration experiments using humic acid (HA) and natural organic matter (NOM) demonstrated remarkable improvements in water flux, rejection efficiency, and fouling resistance. The composite membranes achieved HA rejection rates of up to 98%, with reduced irreversible fouling and higher flux recovery ratios across multiple filtration–cleaning cycles. The proposed antifouling mechanism is attributed to the formation of a stable hydration layer by surface hydroxyl groups, which prevents foulant adhesion and facilitates cleaning. These findings suggest that incorporating TNT@OH into polysulfone membranes is a promising approach for developing high-performance ultrafiltration membranes with enhanced permeability, mechanical robustness, and long-term antifouling stability, thereby making them suitable for advanced water purification applications. Full article

The ATP-dependent inhibition of cytochrome c oxidase (CytOx, complex IV of the electron transport chain) is the second mechanism of respiratory control adjusting mitochondrial respiration in order to prevent excessive electron flow and reactive oxygen species (ROS) production. Here, we investigate how tricarboxylic acid (TCA) cycle metabolites and the subsequent complex I or complex II activities influence this regulatory mechanism. Therefore, CytOx activity was assessed by the oxygen consumption rate after cytochrome c (Cyt c) titration to stimulate complex IV activity in isolated rat heart mitochondria (RHM) and permeabilized AC16 cells. Mitochondrial membrane potential (Δψm) and ROS formation were analysed by flow cytometry. Our results show that TCA cycle intermediates differed in their impact on CytOx activity and subsequent ROS formation. NADH-linked substrates such as α-ketoglutarate, glutamate and malate increased respiratory capacity, but preserved ATP-dependent control of CytOx, indicating that elevated electron supply alone does not necessarily abolish ATP sensitivity. In contrast, succinate, which feeds electrons directly into complex II, strongly increased respiration causing the loss of ATP-dependent respiratory control in both model systems. Despite this strong respiratory effect, succinate induced only modest changes in mitochondrial membrane potential in isolated mitochondria, whereas permeabilized cardiomyocytes exhibited reduced polarization accompanied by increased superoxide formation. Together, these findings demonstrate that the effectiveness of ATP-dependent CytOx inhibition is influenced by TCA cycle activity and depends on the site of electron entry into the respiratory chain. Thus, substrate-dependent modulation of respiratory control links metabolite availability to mitochondrial redox regulation in cardiac cells. Full article

Solid-contact ion-selective electrodes (SC-ISEs) are typically constructed using ion-selective membrane (ISM)-based configurations. However, such structures often suffer from water-layer formation and the weak mechanical stability of the ISM. Herein, we report an ISM-free K⁺-SC-ISE based on a Prussian blue analogue transducer, KMnFe(CN)₆, eliminating the need for a conventional ionophore-based ISM layer. KMnFe(CN)₆ was synthesized via a one-step citrate-assisted co-precipitation method. The material functions as a bifunctional transducer, in which the open framework structure with ion-transport channels enables selective K⁺ recognition, while the redox-active Mn centers facilitate ion-to-electron transduction. The fabricated KMnFe(CN)₆-based K⁺ sensor exhibits a near-Nernstian response with a sensitivity of 52.3 ± 1.0 mV dec⁻¹ and a rapid response time of 25 s. The linear range and limit of detection were determined to 10⁻⁴ to 10⁻¹ M and 5.8 × 10⁻⁵ M, respectively. The sensor also demonstrates selectivity to representative interfering ions, with log K_ij of −2.39 ± 0.12 (Na⁺), −2.86 ± 0.09 (Li⁺), −3.06 ± 0.09 (Ca²⁺), −2.74 ± 0.12 (Mg²⁺) and −0.95 ± 0.08 (NH₄⁺). By eliminating the ISM layer, the water-layer effect is effectively avoided, resulting in excellent long-term stability with a potential drift of 57.2 ± 6.1 μV h⁻¹ over 7 days. The sensor was further applied to the analysis of K⁺ in real lake water samples, where the measured concentration showed good agreement with ion chromatography results. This work provides an ISM-free SC-ISE strategy for ion analysis in water environments. Full article

Background: Corneal organoids derived from pluripotent stem cells have emerged as powerful tools for studying corneal development, disease modeling, and regenerative medicine applications. While previous protocols have successfully generated corneal tissue structures, there remains a need for three-dimensional models that recapitulate the complex cellular architecture and diversity of native human cornea. Methods: We developed a modified spontaneous three-dimensional corneal organoid model using human embryonic stem cells (hESCs) through an adapted Self-formed Ectoderm Autonomous Multi-zone (SEAM) protocol. hESCs were cultured as spheroids in ultra-low-binding plates under normoxic conditions and differentiated over 7–8 weeks. Organoids were characterized using immunofluorescence staining for corneal-specific markers and single-cell RNA sequencing to assess cellular composition and gene expression patterns. Results: Approximately 20% of organoids developed transparent regions characteristic of corneal tissue by day 30 of differentiation. Immunofluorescence analysis revealed spatially organized expression of corneal markers, including ZO-1 and E-cadherin in the outermost epithelial layers, P63α-positive putative limbal stem cells at the epithelial–stromal interface, vimentin-positive stromal cells in the interior, and laminin-1 deposition that suggests Bowman’s membrane formation. The organoids expressed cornea-specific keratins (K3, K12, and K15) and the master regulator PAX6 in appropriate cellular compartments. Single-cell RNA sequencing identified 18 distinct cell clusters, including three corneal epithelium subclusters with differential expression of MUC16, KRT12, and ΔNp63α, two stromal populations with distinct inflammatory profiles, and a corneal endothelium cluster. Transcriptomic analysis confirmed expression of key corneal genes, including AQP3, CDH1, multiple keratins, mucins, and extracellular matrix components (HAS2, CD34, CD44, COL8A1, and KERA). Conclusions: This three-dimensional spheroid-based putative corneal organoid model successfully recapitulates the multilayered architecture and cellular diversity of human cornea, including stratified epithelium, putative limbal stem cells, stroma, and endothelium in spatially appropriate arrangements. The model demonstrates molecular signatures consistent with native corneal tissue and provides a valuable platform for studying corneal development, disease mechanisms, and potential therapeutic applications. Future optimization to improve organoid formation efficiency and functional maturation will enhance the utility of this system for both basic research and translational medicine. Full article

This study demonstrates how synthesis conditions and bacterial cellulose (BC) functionalization influence the physicochemical properties and antibacterial performance of BC membranes containing green-synthesized silver nanoparticles (AgNPs). Mint and avocado-seed extracts enabled AgNP formation in aqueous media but differed in composition. UV–Vis screening across pH and temperature revealed inefficient synthesis at acidic pH, whereas higher temperatures produced broader localized surface plasmon resonance (LSPR) bands. Neutral conditions generated the most intense and narrow LSPR signals. Under optimized conditions (pH 7, 23 °C), AgNPs were confirmed by TEM, and their colloidal properties differed between extracts: mint-derived particles exhibited smaller hydrodynamic diameters and lower polydispersity than avocado-derived AgNPs. Two BC functionalization strategies were evaluated: immersion in pre-formed AgNP dispersions and in situ synthesis within the BC matrix. In situ membranes displayed stronger and better-defined LSPR peaks. Agitation released nanoparticles from all BC-AgNP membranes, with smaller species released from in situ systems. Antibacterial assays against E. coli showed greater bactericidal activity for in situ membranes. Avocado-derived in situ BC-AgNPs produced larger inhibition halos and prevented bacterial regrowth in liquid culture. Overall, in situ green synthesis within BC provides an effective route to robust and sustainable antibacterial BC membranes. Full article

Natural killer (NK) cells are promising effectors for cancer immunotherapy, as they can recognize and eliminate tumor cells without prior antigen sensitization. However, insufficient tumor recognition remains a critical limitation that reduces the anticancer efficacy of NK cells against solid tumors. To address this limitation, we developed a lipid-mediated cell membrane engineering strategy to enhance the targeting and cytotoxic efficacy of NK cells toward solid tumors, particularly ovarian cancer cells. In this strategy, poly-L-glutamic acid (PLE) was employed as an ovarian cancer-targeting module due to the specific affinity of PLE for cholesterol-rich membrane domains. To display PLE on NK cells, a lipid moiety is incorporated to anchor PLE onto the NK cell membrane via hydrophobic insertion, enabling rapid and non-genetic surface modification. As a result, the surface-engineered NK cells with PLE-Lipid (i.e., PLE-NK) displayed PLE on the NK cell surface, allowing direct recognition of ovarian cancer cells without compromising the intrinsic properties of NK cells. This enhanced recognition subsequently increased NK–cancer cluster formation by promoting interactions between membrane-presented PLE on NK cells and cholesterol on ovarian cancer cells. Consequently, PLE-NK cells exhibited enhanced cytotoxicity against ovarian cancer cells (i.e., OVCAR-3 cells) and effectively disrupted 3D tumoroids, while PLE-NK cells showed no off-target effects on normal fibroblasts. Collectively, these findings demonstrate that PLE-Lipid-mediated NK surface engineering provides a simple and effective strategy to improve the tumor targeting ability of NK cells and offers a promising platform for NK cell-based immunotherapy against ovarian cancer. Full article

Hybrid gas separation technologies combining different physicochemical mechanisms represent a promising approach for the efficient treatment of complex natural gas mixtures. In this work, a hybrid process integrating gas hydrate crystallization and membrane gas separation was investigated for the upgrading of multicomponent natural gas-containing hydrocarbons (C₁–C₄), acid gases (CO₂ and H₂S), and inert components. Polysulfone hollow-fiber membranes were fabricated, and their gas transport properties were experimentally determined using an eight-component quasi-real natural gas mixture under elevated pressure conditions. The obtained mixed-gas permeance values were used as input parameters for the development of a detailed mathematical model of a hollow-fiber membrane module implemented in the Aspen Custom Modeler. The model was applied to simulate membrane separation of both gas- and hydrate-derived streams produced by the gas hydrate crystallizer. Simulation results were analyzed in terms of hydrocarbon composition, acid gas removal efficiency, and hydrocarbon recovery as a function of the stage-cut. The modeling predictions were validated experimentally using a laboratory membrane module integrated with the gas hydrate crystallization unit. Good agreement between the experimental data and simulation results was observed for all major components. The deviation between modeled and experimental concentrations remained small, while the discrepancy in hydrocarbon recovery was higher and reached approximately 10–20%, which is attributed to the cumulative uncertainty of flow rate and composition measurements. These results confirm the adequacy of the developed model. The hybrid process demonstrates strong complementarity between the thermodynamic selectivity of hydrate formation and the transport selectivity of membrane separation, enabling efficient removal of acid gases while maintaining acceptable hydrocarbon recovery. The results indicate that the proposed gas hydrate–membrane hybrid process is a promising strategy for advanced natural gas purification and upgrading. Full article

The rise in antimicrobial resistance represents a significant challenge to global health. The reason partially lies in an inappropriate use of conventional antibiotics and the subsequent rapid spread of multidrug-resistant pathogen strains. This emergency requires an urgent search for conceptually new antimicrobial agents. A viable alternative to conventional antibiotics is antimicrobial peptides (AMPs), which are ribosomally synthesized molecules with considerable potential as next-generation anti-infectious therapeutics. Previously, we have reported on the β-hairpin peptide Ap9, an analog of abarenicin from the marine polychaeta Abarenicola pacifica, with potent activity against key Gram-negative pathogens. Here, it is shown that Ap9 acts in a manner resembling polymyxin B, namely via interaction with lipopolysaccharide (LPS), and retains its activity against polymyxin-resistant isolates without observed cross-resistance, and causes insignificant damage in cytoplasmic membrane at bactericidal concentrations. NMR spectroscopy reveals that LPS binding induces a conformational rearrangement of Ap9, its dimer formation, and local structural remodeling of the peptide region (residues 8–12) into 3₁₀-helix. Bacterial resistance to Ap9 was found to be relatively low with a reduced susceptibility associated with infrequent genetic alterations, such as the mutation in lptD or the deletion in mlaA. Furthermore, Ap9 demonstrates a favorable tolerability, a wider therapeutic window than that of polymyxin B, and a sufficiently long half-life through the systemic use, as well as in vivo efficacy in murine models of Gram-negative infections, including sepsis caused by the mcr-1-harboring Escherichia coli strain. The obtained results point to Ap9 as a promising candidate for further preclinical studies aimed at development of an alternative to polymyxins. Full article