Search Results (2,418)

Adult bone marrow-derived mesenchymal stem cells (BMSCs) are multipotent progenitors capable of differentiating into diverse cell lineages, including osteogenic, chondrogenic, adipogenic, and neuronal lineages. In BMSCs, intracellular glutathione (GSH) is a critical determinant of stemness maintenance and differentiation outcomes. However, how intracellular GSH homeostasis is regulated during BMSC-to-neuron differentiation remains unclear. In neurons, GSH synthesis critically depends on cysteine uptake mediated by the excitatory amino acid carrier 1 (EAAC1). Here, we investigated the expression, subcellular localization, and functional contribution of EAAC1 and its regulatory protein, glutamate transporter-associated protein 3-18 (GTRAP3-18) in mouse BMSCs and neuron-like BMSCs generated by Notch intracellular domain-based induction (NICD-3F BMSCs). BMSCs exhibited higher intracellular GSH levels than NICD-3F BMSCs, despite comparable levels of EAAC1 protein. In contrast, EAAC1-dependent cysteine uptake and plasma membrane localization of EAAC1 were markedly reduced in BMSCs, indicating differentiation-dependent regulation of EAAC1 trafficking. Treatment with the xCT inhibitor erastin reduced intracellular GSH levels in both BMSCs and NICD-3F BMSCs. GTRAP3-18 expression was high in BMSCs and significantly reduced in NICD-3F BMSCs. Notably, GTRAP3-18 knockout decreased intracellular GSH levels in BMSCs without altering total EAAC1 protein or intracellular cysteine levels, whereas in NICD-3F BMSCs, both GSH and EAAC1 protein levels were increased. These findings demonstrate lineage-dependent divergence in GSH regulatory mechanisms and reveal previously unrecognized functions of GTRAP3-18 in redox control during stem–to–neuron differentiation. Full article

Regulated cell death is essential for tissue homeostasis, immune defense, and disease progression, yet the lipid-based regulatory mechanisms that coordinate cell death signaling remain incompletely understood. Protein palmitoylation is a dynamic and reversible lipid post-translational modification that controls protein membrane association, trafficking, stability, and signaling complex assembly. This review summarizes the regulatory roles of palmitoylation and depalmitoylation in major forms of regulated cell death, including apoptosis, necroptosis, pyroptosis, ferroptosis, and autophagy-related cell death. Particular attention is given to representative palmitoylated substrates, including Fas cell surface death receptor (Fas), receptor-interacting protein kinase 1 (RIPK1), NLR family pyrin domain containing 3 (NLRP3), gasdermin D (GSDMD), glutathione peroxidase 4 (GPX4), solute carrier family 7 member 11 (SLC7A11), autophagy-related 16 like 1 (ATG16L1), and Beclin1. These substrates illustrate how palmitoylation links membrane organization, metabolic status, inflammatory signaling, and cell fate decisions. Disease-oriented evidence further indicates that dysregulated palmitoylation contributes to cancer, neurodegenerative diseases, and inflammatory or immune-related disorders by modulating cell death resistance, inflammatory amplification, immune evasion, or impaired proteostasis. Current challenges include limited quantitative information on palmitoylation dynamics, incomplete evidence for some enzyme–substrate relationships, and insufficient distinction between disease-driving and secondary palmitoylation events. Targeting zinc finger Asp-His-His-Cys (zDHHC) palmitoyl acyltransferases, depalmitoylating enzymes, or specific palmitoylated substrates may provide new therapeutic opportunities. Overall, this review positions protein palmitoylation as a dynamic molecular switch linking lipid metabolism, membrane signaling, regulated cell death, and disease remodeling. Full article

To address the global water crisis, desalination technologies contribute about 1% of the global freshwater supply. Membrane-based desalination technologies offer high performance, operational ease, cost-effectiveness and high scalability compared to conventional thermal desalination modes. Among all membrane-based technologies, reverse osmosis is prevailing globally. However, the high energy demand of the reverse osmosis process and fouling in case of hypersaline feed streams motivate the exploration of alternative technologies, i.e., pervaporation. Pervaporation desalination involves dense hydrophilic polymer membranes to deal with high salt streams at low cost, along with less fouling than a few other membrane processes, i.e., reverse osmosis and membrane distillation. Mass transport through pervaporation desalination membranes is well-explained by solution-diffusion theory involving a tri-stage transfer, i.e., sorption, diffusion and evaporation. Since the last few decades, a green approach in all domains has offered chemical products and processes with the least hazards and minimal waste production. Application of biodegradable materials like poly(lactic acid) in combination with suitable green solvents, e.g., ethyl lactate, methyl lactate, cyrene, dimethyl isosorbide and gamma valerolactone for pervaporation desalination would be a good roadmap to meet the sustainability criterion. Some intrinsic features of poly(lactic acid) that make it a ‘material of choice’ for pervaporation desalination include hydrophilicity imparted by the presence of polar ester groups, high salt rejection, biodegradability with simple mineralization products, i.e., H₂O and CO₂, sustainable production, low toxicity, low carbon footprint, ease of processing and versatility. Poly(lactic acid) undergoes four interrelated degradation mechanisms: hydrolytic degradation, biodegradation, thermal degradation and photodegradation. The concern for poly(lactic acid) based pervaporation desalination is increased hydrolytic cleavage of poly(lactic acid) at high temperatures, which requires some modifications, e.g., nanoenhancement, additions of crosslinkers, surface modifications, addition of other polymers to prepare blends and post-treatments. These modifying strategies result in an increased stability and better performance of poly(lactic acid) films. However, optimization of various parameters relevant to such modifications leaves room for further research. This review offers a critical analysis of the need for biodegradable polymers with special focus on poly(lactic acid) rather than their fossil fuel-based alternatives, the environmental and health effects of all these polymers, cost estimation and possible performance-efficient, green and eco-friendly solutions. Full article

High-Resolution Site Characterization (HRSC) offers a promising approach to delineate spatially heterogeneous contamination in complex petrochemical sites, overcoming limitations of conventional discrete sampling. This study implemented an integrated HRSC framework combining surface soil microbial metabolic gas/functional gene detection, geophysical surveys (time-domain electromagnetics and ground-penetrating radar), and Membrane Interface Probe (MIP) sensing at a petrochemical facility in southern China. Results identified composite contamination (aromatic hydrocarbons, short-chain petroleum hydrocarbons, alkanes) primarily concentrated at 5–9 m depth, with a heavily contaminated zone of 1163 m² and a total influence area of 17,724 m². The contamination plume showed high spatial correlation with an underground wastewater storage pond, confirmed as the primary leakage source. Post-remediation monitoring indicated restoration of natural groundwater flow and reduced contaminant concentrations. Compared to traditional drilling, the HRSC approach improved resolution from meter to centimeter scale, reduced investigation time by 75%, and lowered overall costs by >30% through targeted sampling and real-time data acquisition. This study validates HRSC as an efficient, accurate, and cost-effective strategy for contamination delineation and source identification in operational industrial sites, supporting precise remediation and site redevelopment. Full article

Genetically encoded voltage indicators (GEVIs) have long promised optical access to membrane potential, yet their adoption has lagged significantly behind genetically encoded calcium indicators. A central but underappreciated reason is that the metrics used to evaluate and compare GEVIs—fractional fluorescence change (ΔF/F), kinetics, and signal-to-noise ratio—rest on an assumption that is frequently violated: that GEVI fluorescence reflects a single underlying process. In this perspective, we argue that GEVI signals are composite optical measurements, arising from the superposition of voltage-dependent fluorescence, intracellular and nonresponsive signal, background, and contributions from neighboring cells. Under these conditions, ΔF/F is not a measure of sensor sensitivity but a contrast metric whose value depends on baseline fluorescence composition, optical sampling, and imaging configuration. This reinterpretation has two key consequences. First, it explains a substantial source of variability in GEVI performance that is currently attributed to noise or experimental inconsistency. Second, and more importantly, it reveals that the complexity of GEVI signals is not a limitation to be minimized but a resource to be exploited. By resolving composite signal components, GEVIs can report multiplexed physiological variables, expose hidden conformational states of voltage-sensing domains, probe membrane organization, and reveal intracellular and intercellular electrical coupling. We propose that realizing the full potential of GEVIs requires treating ΔF/F not as a gold standard for sensor performance, but as one interpretable component of a richer optical measurement whose structure encodes multiple layers of cellular physiology. Full article

The extraordinary genetic diversity of human immunodeficiency virus type 1 (HIV-1), driven by high mutation and recombination rates, poses significant challenges for diagnostics, therapy, and vaccine development. While variable regions enable immune escape, hyperconserved regions are critical for viral function and represent promising targets for novel therapeutic interventions. This study aimed to develop and validate a bioinformatic algorithm for quantitative assessment of sequence conservation and automated identification of functionally significant conserved regions across all major HIV-1 proteins. A total of 1119 full-length HIV-1 genome sequences representing major subtypes (A1, A2, A6, B, C, D, F1, F2, G, H, J, K) were analyzed. Normalized Shannon entropy (S-index) was calculated for each alignment column. Statistical thresholds for conserved regions were established using 95% confidence intervals derived from bootstrap resampling. Two complementary algorithms, clustering and local maxima detection, were applied to identify conserved regions, which were subsequently mapped to known functional domains based on literature data. Protein conservation varied markedly, with S_m values ranging from 0.784 (Vpu) to 0.920 (Pol). Gag, Pol, and Vpr demonstrated the highest overall conservation, while Env, Rev, Tat, and Vpu exhibited pronounced variability interspersed with conserved domains. In total, 25 conserved regions in Gag, 49 in Pol, 28 in Env, and 6–4 regions in accessory proteins (Vif, Vpr, Rev, Tat, Nef, Vpu) were identified. These regions corresponded to critical functional elements including enzyme catalytic centers, zinc fingers, receptor-binding sites, protein interaction interfaces, and membrane-anchoring domains. The developed computational framework enables statistically grounded identification of evolutionarily constrained regions across analyzed HIV-1 subtypes. The identified conserved regions represent candidate sites for further investigation and may inform downstream studies focused on antiviral target prioritization, immunogen design, and diagnostic assay development. However, their translational applicability requires additional analytical, structural, and experimental validation. Full article

Huntington’s disease (HD) is a neurodegenerative disorder caused by the expansion of the CAG trinucleotide in the exon 1 of the huntingtin gmodellerene. This abnormal expansion produces a mutant huntingtin (mHTT) protein with extended polyglutamine (polyQ) tracts. Although the molecular mechanisms underlying HD onset and progression remain poorly understood, aberrant folding, aggregation, and membrane interactions of mHTT are considered central to disease pathogenesis. In this study, we used molecular dynamics (MD) simulations to investigate the structural properties, dimerization propensity, and membrane lipid interaction of mHTT carrying 70 polyQ repeats (mHTT-Q70). Our analyses revealed that mHTT-Q70 retains partially structured α-helical conformations with increased flexibility within the polyQ domain, thus being predisposed to misfolding. Coarse-grained MD simulations further revealed a strong tendency of mHTT-Q70 to dimerize, indicating that early oligomerization may represent a critical step in protein aggregation. Interestingly, we show that membrane cholesterol content dose-dependently promotes dimeric mHTT-Q70—but not monomeric mHTT-Q70—association with neuronal membrane models, which was observed for 70% of simulation time at 40% cholesterol content. Such a cholesterol-dependent membrane binding of dimeric mHTT-Q70 suggests that membrane lipid composition may represent a critical checkpoint in the early stages of mHTT-Q70 aggregation, and of cytotoxicity thereof. Moreover, distinct neuronal membrane lipids like phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine differently contributed to mHTT-Q70 binding, highlighting the complexity of such a lipid-dependent modulation. Taken together, these findings underscore the dynamic interplay between polyQ-driven misfolding, dimerization, and membrane lipids in HD pathogenesis, suggesting that modulation of membrane composition, and in particular of cholesterol levels, may be a novel action point to design therapeutic drugs for HD. Full article

Magnetic targeting of drug carriers is commonly studied at macroscopic scales, while its impact on drug transport across individual cell membranes remains poorly quantified. Here, we present a theoretical and numerical model of magnetically assisted drug transport across the membrane of a single tumor cell exposed to magnetic field gradients. Extracellular transport is described by an advection–diffusion equation that couples passive diffusion with magnetophoretic drift, whereas intracellular transport is governed by diffusion and first-order uptake kinetics. The cell membrane is modeled as a semi-permeable interface with finite permeability, providing explicit coupling between extracellular and intracellular domains. Assuming spherical symmetry, the coupled transport equations are solved using finite-difference schemes, with magnetic forcing represented through an effective drift velocity $v_{\mathrm{m}\mathrm{a}\mathrm{g}}$ and interpreted using the magnetic Peclet number. To enable a controlled comparison between healthy and tumor cells, identical geometric, diffusive, and magnetic parameters are used, while biological differences are introduced solely through membrane permeability and intracellular uptake rates. By separating cumulative membrane delivery from cumulative intracellular uptake, the model resolves ambiguities arising from heterogeneous uptake kinetics. The results show that magnetophoretic drift enhances near-membrane drug accumulation and effective transmembrane flux without modifying intrinsic membrane properties. Magnetic targeting therefore acts as a transport amplifier, magnifying pre-existing biological differences and producing a larger model-predicted delivery advantage in tumor cells. Overall, the framework identifies the magnetic Peclet number as the key parameter governing the transition from diffusion-dominated to drift-enhanced cellular drug transport. Full article

The CD40–CD154 receptor-ligand axis is a core costimulatory regulator of antiviral immunity in mammals, but its functional role in teleosts remains largely unknown. Here, we identified the CD40 and CD154 homologs (MsCD40 and MsCD154) from largemouth bass (Micropterus salmoides), a globally farmed perciform teleost. Bioinformatic analysis confirmed that MsCD40 and MsCD154 harbor the conserved domain architectures of tumor necrosis factor receptor superfamily and TNF superfamily, respectively, with a teleost-specific phylogenetic clustering pattern. Both genes were ubiquitously expressed in immune-relevant tissues, and their transcription was dynamically regulated in response to viral hemorrhagic septicemia virus (VHSV) and largemouth bass virus (LMBV) challenge in vivo. Co-immunoprecipitation and immunofluorescence co-localization assays verified that MsCD40 and MsCD154 physically interact at the plasma membrane, forming a functional receptor-ligand complex. Functional assays showed that overexpression of either MsCD40 or MsCD154 significantly suppressed VHSV and LMBV infection in vitro. Furthermore, MsCD40 and MsCD154 overexpression dose-dependently activated nuclear factor-κB (NF-κB) reporter activity, and markedly upregulated the transcription of NF-κB downstream effector genes, including IL-8, NLRP3 and P105, under both VHSV and LMBV infection. Collectively, our findings demonstrate that the teleost CD40–CD154 costimulatory axis restricts both RNA and DNA viral infection in largemouth bass through NF-κB-mediated immune activation, which provides promising molecular targets for the development of broad-spectrum antiviral strategies in largemouth bass aquaculture. Full article

Reactive polymeric membranes are emerging as promising platforms for advanced water and wastewater treatment because they combine separation with in situ contaminant transformation. Unlike conventional membranes, which mainly retain pollutants, reactive polymeric membranes can enrich, activate, and degrade micropollutants during permeation through built-in radical, redox-active, conductive, or porous catalytic domains. This review discusses the development of intrinsic reactive polymer membranes for oxidative filtration, with emphasis on the links between polymer structure, transport behavior, reactive oxygen species generation, and degradation pathways. Key membrane classes are discussed, including stable-radical polymers, redox-active polymer networks, conductive polymer membranes, and porous conjugated polymer catalytic layers. The review also highlights the importance of reactive transport kinetics, including convection–diffusion–reaction coupling, residence time, Damköhler and Péclet numbers, and adsorption-enhanced degradation. Challenges such as fouling, polymer aging, leaching, byproduct formation, and toxicity-aware benchmarking are discussed within a broader roadmap for technology translation. The review identifies the grand challenges and milestone-based priorities for developing and deploying reactive polymer membranes, including performance targets, standardized reporting, realistic water matrices, scale-up, technology readiness levels, techno-economic analysis, life cycle assessment, artificial intelligence, and digital twins. Together, these elements guide the translation of reactive polymer membrane systems from laboratory research toward full-scale water treatment applications. Full article

The PIN-LIKES (PILS) gene family is crucial for regulating auxin homeostasis and stress adaptation in plants; nevertheless, a comprehensive study on this family in alfalfa (Medicago sativa) remains insufficient. This research found 46 MsPILS genes within the tetraploid alfalfa genome and categorized them into four subfamilies. The genes are irregularly allocated throughout 16 chromosomes, with tandem duplications acting as a primary catalyst for family expansion. Analysis indicated that all MsPILS proteins contain the conserved Mem_trans domain. The promoter study revealed that MsPILS genes had many cis-elements that respond to abiotic stressors and hormones. qRT-PCR research indicated that MsPILS genes exhibit variable expression across several tissues and respond to multiple abiotic stressors. Protein–protein interaction (PPI) research revealed PIN3, PIN5, and PIN6 as principal interacting partners of the MsPILS proteins. Subcellular localization studies indicated that MsPILS1c is in the nucleus, plasma membrane, and endoplasmic reticulum (ER). This research offers significant genetic resources and a theoretical framework for elucidating the activities of PILS genes and for molecular breeding aimed at improving stress tolerance in alfalfa. Full article

Andes virus (ANDV), a highly pathogenic orthohantavirus, enters host cells through low pH–triggered membrane fusion mediated by the Gc glycoprotein, a class II fusion protein containing a single C-terminal transmembrane domain (TMD). While the ectodomain has been extensively characterized, the role of the TMD in late-stage fusion remains unclear. Here, we investigated the minimal functional length and sequence requirements of the ANDV Gc TMD using site-directed mutagenesis. C-terminal deletion mutants and serine-to-alanine substitutions were evaluated for protein expression, virus-like particle production, cell–cell fusion, pseudotyped vector entry, and hemifusion activity. Deletion of the Gc cytoplasmic tail (CT) or a single C-terminal TMD residue was tolerated, whereas deletion of two or more residues impaired particle production and fusion, indicating that at least 21 of the 22 TMD residues are required for efficient membrane fusion and viral entry. Hemifusion assays showed that deletion of two or three residues, or substitution of the strictly conserved S1121, allowed lipid mixing but blocked progression to full fusion, while deletion of four residues also abolished hemifusion. In contrast, mutation of the less conserved S1126 had minimal effect. These results identify a precise TMD length and a conserved polar TMD residue as critical determinants of fusion pore formation in ANDV. Full article

Background/Objectives: BRI is a synthetic arylamide polymer designed to mimic the electrostatic and amphiphilic features of defensin-type antimicrobial peptides (AMPs), although its molecular organization and activity have not been experimentally validated. This study presents the first integrated computational and experimental characterization of BRI to define the physicochemical basis of its AMP-like behavior and membrane interactions. Methods: Molecular modelling was used to evaluate the structural and electrostatic properties of BRI. Model lipid membranes were used to study membrane interactions. Fluorescence spectroscopy, electrochemical measurements, and ζ-potential analyses were performed to characterize membrane insertion, aggregation, ionic conductance, and membrane resistance. Microbiology assays evaluating synergy with azole were also assessed. Results: Molecular modelling showed that BRI is a flexible molecule with cationic and hydrophobic surfaces, a strong amphiphilic dipole, and a dominant +4 charge state, explaining its sensitivity to ionic strength and membrane interactions. BRI displayed two membrane-dependent mechanisms of action. In zwitterionic phospholipid membranes, BRI resembled canonical AMPs, showing membrane insertion, pore formation, and increased ionic conductance. In anionic ergosterol-containing membranes mimicking fungal cells, BRI exhibited sterol-dependent insertion, in-plane aggregation, and modulation of membrane resistance without pore formation. Fluorescence, electrochemical, and ζ-potential measurements supported BRI–BRI interactions at the membrane interface and sensitivity to lipid domain organization. BRI also synergized with azole antifungal drugs, suggesting a mechanistic role for ergosterol in its antifungal activity. Conclusions: These findings reveal a sterol- and domain-mediated mechanism for arylamide polymers and identify lipid organization as a key determinant of antifungal activity. The dependence of BRI activity on ergosterol content provides a mechanistic explanation for its synergy with azole antifungals and supports further investigation of BRI as a membrane-active antifungal agent. Full article

Drought and soil salinization severely limit the productivity of global agriculture and forestry, highlighting the urgency of identifying stress-resistant genes for molecular breeding. B-box (BBX) proteins constitute a class of zinc finger transcription factors that play significant roles in plant abiotic stress responses. Amorpha fruticosa (A. fruticosa) is a perennial woody plant with exceptional adaptability to harsh environments, serving as a valuable resource for mining stress-resistant genes. In this study, the AfBBX gene was cloned from A. fruticosa, and its function in stress tolerance was systematically analyzed. Bioinformatics analysis confirmed that AfBBX contains a conserved ZnF-BBOX domain and shares functional conservation with the BBX protein family. Quantitative real-time polymerase chain reaction (qRT-PCR) revealed tissue-specific expression of AfBBX, with the highest expression in stems and the lowest in young leaves. Furthermore, AfBBX expression was dynamically regulated in roots and leaves of A. fruticosa under treatments of 5 μM ABA (drought mimic), H₂O₂ (oxidative stress), 10% PEG600 (osmotic stress), and NaHCO₃ (alkaline stress). Transgenic tobacco lines overexpressing AfBBX showed enhanced tolerance to osmotic and salt–alkali stresses at both germination and seedling stages. Meanwhile, compared to wild-type (WT) tobacco, transgenic lines exhibited higher germination rates, longer root lengths, and greater fresh weights under stress conditions. Under natural drought and salt–alkali stresses, transgenic tobacco maintained higher chlorophyll fluorescence intensity (Fv/Fm values), elevated activities of antioxidant enzymes [superoxide dismutase (SOD)], and reduced malondialdehyde (MDA) content. In conclusion, AfBBX enhances stress tolerance by mitigating photosystem damage, increasing reactive oxygen species (ROS) scavenging capacity, and reducing membrane lipid peroxidation. The findings from this study provide novel insights into the molecular mechanism underlying AfBBX-mediated stress resistance and offer valuable genetic resources for breeding drought- and salt-tolerant crops and forest trees. Full article

Hepatitis C virus (HCV) infection remains a major global health burden, and no vaccine preventing chronic infection is available. The envelope glycoproteins, E1 and E2, form a complex essential for viral entry; however, the mechanisms governing E1/E2 assembly and stability remain incompletely defined. Here, we investigated the role of the E1/E2 transmembrane (TM) regions in HCV infectivity using chimeras of JFH1-based recombinants with isolate-specific Core-NS2 sequences in which the C-terminal TM domains of E1 (TME1), E2 (TME2), or both (TME1E2) from the H77 isolate (genotype 1a) replaced those of isolates representing genotypes 1–6. We further introduced the TM domains of S52 (genotype 3a) or J6 (genotype 2a) into H77 and included reciprocal swaps between J6 and S52. Most TM-swap chimeras displayed impaired infectivity; however, serial passaging led to partial recovery associated with adaptive mutations in E1/E2 mapping not only to the C-terminal TM regions but also to the E1 stem and the internal E1 TM region (iTME1). Extending the TME1 swap to include upstream α-helical segments improved infectivity in selected chimeras, whereas inclusion of iTME1 abolished infectivity. These findings support functional interactions between membrane-associated regions of E1/E2 and their ectodomains and highlight their relevance for E1/E2-based HCV vaccine design. Full article