Search Results (663)

This study reports the effect of pH (2, 7, 10) and heat treatment (80 °C for 30 min) on the oil–water (o/w) interfacial behavior of hemp seed protein isolate (HPI) aqueous dispersions. The physicochemical, interfacial adsorption, rheology, and emulsifying properties of protein dispersions were evaluated. HPI dispersions at pH 10 exhibited the highest water solubility (60%), the greatest net charge (−27 mV), and the lowest hydrophobicity (~5 a.u.), promoting o/w interfacial pressure (π) and interfacial viscoelasticity. Strong interfacial viscoelastic protein layers (E^* = 25 mN/m) were also observed under acidic conditions (pH 2), where proteins exhibited high solubility (40%), a high positive net charge (21 mV), and increased hydrophobicity (46 a.u.). HPI dispersions in their neutral state (pH 7) were not able to form stable o/w emulsions due to their poor physicochemical properties such as low solubility (18%), low surface charge (−18 mV), and hydrophobicity (~5 a.u.). Heat treatment significantly increased the charge and hydrophobicity of both neutral and alkaline proteins (~30 mV and ~10 a.u., respectively), increasing their particle size distribution and ultimately reducing their interfacial protein layer elasticity (E^* = 20 and 13 nM/m, respectively). While particles at acidic conditions showed high thermal resistance, heat treatment improved the emulsifying stability in alkaline conditions while further reducing it in the neutral state. Overall, HPI dispersions demonstrated the ability to form stable emulsions at both alkaline and acid pHs, with those formed at pH 2 exhibiting a lower droplet size and superior stability. Full article

New nano-biomaterials for specific dentistry applications have been developed thanks to contributions from materials science. The present work aims to characterize the physicochemical properties of a composite nanomaterial scaffold in block form for maxillofacial bone regeneration applications. The scaffold was composed of block-shaped elements and consisted of a mixture of nano-hydroxyapatite, β-tricalcium phosphate, and type I collagen of bovine origin. Collagen I molecule is biodegradable, biocompatible, easily available, and a natural bone matrix component. The biomaterial was analyzed using a range of methods, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), chemical composition microanalysis, and X-Ray diffractometry (XRD). The wettability was measured. This was carried out by measuring the contact angle of a 0.9% NaCl solution on the surface. Differential scanning calorimetry (DSC) was used to measure the phase transformation temperatures. In the SEM and TEM analyses, it was possible to identify the layers of the materials and, with microanalysis, quantify their chemical composition. The XRD spectra showed the presence of nano-hydroxyapatite and ß-TCP. Wettability testing revealed that the material is highly hydrophilic, and BM-MSC culture analyses demonstrated that the biomaterial can promotes cell adhesion and interaction. The higher wettability is due to the higher density of the porous material observed in the SEM analysis. The results of the DSC testing showed that the sample analyzed undergoes endothermic transitions and transformation between 25 and 150 °C. The first phase transformation during heating occurs at 61.1 °C, which is above body temperature. The findings demonstrated that the composite was devoid of any contamination arising from manufacturing processes. It can be concluded that the n-HA/β-TCP and type 1 collagen are free of manufacturing contaminants. They also have high wettability, which increases the spreading of body fluids on the biomaterial’s surface and its interactions with cells and proteins. This makes them suitable for clinical application. Full article

Introduction: Incomplete polymerization of in vivo composite resins (CR) poses a significant problem, with monomer-to-polymer conversion rates ranging from around 60 to 75%. Furthermore, oxygen exposure hampers polymerization in the surface layers. This research aims to evaluate the autophagy-inducing potential of three types of CRS and to explore the role of the Akt/mTOR–autophagy–apoptosis crosstalk in composite resin-induced autophagy. The study uses human gingival fibroblasts and three composite materials (M1 and M2, which are 3D printed, and M3, which is milled). Materials and Methods: SEM analysis was performed on the dental materials, and cells kept in contact for 24 h were subjected to tests including the following: MTT, LDH, NO, immunological detection of proteins involved in autophagy and apoptosis, as well as immunofluorescence tests (Annexin V and nucleus; mitochondria and caspase 3/7; detection of autophagosomes). Results: The results showed statistically significant decreases in cell viability with M1 and M2, linked to increases in cytotoxicity and oxidative stress (LDH and NO). Using multiplex techniques, significant increases in glycogen synthase kinase 3 beta (GSK3b) protein were observed in both M1 and M2; a decrease in mTOR (mechanistic target of rapamycin) expression was noted in M1 and M3. Immunofluorescence tests revealed an increase in Annexin V across all materials studied, and an increase in autophagosomes in M1 and M2, whereas a decrease was observed in M3. Conclusions: The relationship between apoptosis and autophagy is highly complex, indicating they may occur sequentially, coexist, or be mutually exclusive. Understanding this complex interplay can help in designing new 3D-printing protocols and monomer compositions to prevent autophagy imbalance. Full article

Background/Objectives: Impaired intestinal barrier function is a hallmark of inflammatory bowel disease (IBD). Akkermansia muciniphila and its outer membrane protein Amuc_1100 can enhance this barrier, but the clinical application of Amuc_1100 is limited by the fastidious growth of its native host. This study aimed to overcome this by utilizing the robust probiotic Lacticaseibacillus paracasei L9 for targeted Amuc_1100 delivery. Methods: We engineered Lc. paracasei L9 to express Amuc_1100 via intracellular (pA-L9), secretory (pUA-L9), and surface-display (pUPA-L9) strategies. Their efficacy was assessed in Lipopolysaccharide (LPS)-induced macrophages and a dextran sulfate sodium (DSS)-induced colitis mouse model, evaluating inflammation, barrier integrity, and mucosal repair. Results: The secretory (pUA-L9) and surface-display (pUPA-L9) strains most effectively suppressed pro-inflammatory cytokines (IL-6, IL-1β, and TNF-α) in macrophages. In mice, both strains alleviated colitis and outperformed native A. muciniphila in improving disease activity. Crucially, they exhibited distinct, specialized functions: pUA-L9 acted as a systemic immunomodulator, reducing pro-inflammatory cytokines (IL-6, IL-1β, and TNF-α), elevating anti-inflammatory mediators (IL-4 and IL-10), and promoting goblet cell differentiation; notably, the inhibitory effect of pUA-L9 on IL-6 expression was approximately 2-fold greater than that of pUPA-L9. In contrast, pUPA-L9 excelled in local barrier repair, uniquely restoring mucus layer integrity (Muc1, Muc2, and Tff3) and reinforcing tight junctions (ZO-1, Occludin, Claudin1, Claudin3, and Claudin4). In particular, pUPA-L9 increased Muc2 expression by approximately 3.6-fold compared with pUA-L9. Conclusions: We demonstrate that the subcellular localization of Amuc_1100 within an engineered probiotic dictates its therapeutic mode of action. The complementary effects of secretory and surface-displayed Amuc_1100 offer a novel, spatially targeted strategy for precision microbiome therapy in IBD. Full article

Metallic biomaterials play essential roles in modern medical devices, but their long-term performance depends critically on protein adsorption and subsequent cellular responses at material interfaces. This review examines the molecular mechanisms governing these interactions and discusses surface modification strategies for controlling biocompatibility. The physicochemical properties of oxide layers formed on metal surfaces—including Lewis acid-base chemistry, surface charge, surface free energy, and permittivity—collectively determine protein adsorption behavior. Titanium surfaces promote stable protein adsorption through strong coordination bonds with carboxylate groups, while stainless steel surfaces show complex formation with proteins that can lead to metal ion release. Surface modification strategies can be systematically categorized based on two key parameters: effective ligand density (σ_eff) and effective mechanical response (E_eff). Direct control approaches include protein immobilization, self-assembled monolayers, and ionic modifications. The most promising strategies involve coupled control of both parameters through hierarchical surface architectures and three-dimensional modifications. Despite advances in understanding molecular-level interactions, substantial challenges remain in bridging the gap between surface chemistry and tissue-level biological performance. Future developments must address three-dimensional interfacial interactions and develop systems-level approaches integrating multiple scales of biological organization to enable rational design of next-generation metallic biomaterials. Full article

The formation of mixed adsorption layers of amyloid fibrils of a plant protein, oat globulin (OG), and a strong polyelectrolyte, sodium polystyrene sulfonate (PSS), at the liquid–gas interface was studied by measurements of the kinetic dependencies of surface tension, dynamic surface elasticity, and ellipsometric angle. The micromorphology of the layers was determined by atomic force microscopy. A strong increase in the surface elasticity was discovered when both components had similar concentrations and formed a network of threadlike aggregates at the interface, thereby explaining the high foam stability in this concentration range. The sequential adsorption of PSS and OG resulted in the formation of thick mixed multilayers and the surface elasticity increased with the number of duplex layers. Full article

Biodegradable magnesium (Mg) alloys are promising materials for temporary orthopaedic implants, combining favourable mechanical properties and superplastic behaviour with in vivo resorption. This enables (i) prolonged implant duration, (ii) fabrication of complex-shaped prostheses via superplastic forming (SPF), (iii) elimination of removal surgery, and (iv) reduced risk of long-term complications. However, rapid corrosion under physiological conditions remains a major limitation, highlighting the need for surface treatments that slow degradation while preserving implant integrity. This study investigates the effects of hydrothermal surface treatment on MgAZ31-SPF alloys, focusing on immunomodulatory responses, antibacterial potential, and degradation behaviour. Hydrothermally treated MgAZ31-SPF (MgAZ31-SPF-HT) extracts released lower Mg²⁺ concentrations (29.2 mg/dL) compared to untreated MgAZ31-SPF (47.5 mg/dL) while maintaining slightly alkaline pH (7–8.7), indicating improved control of early degradation. In vitro assays with human peripheral blood mononuclear cells (hPBMCs) and normal human dermal cells (NHDCs) showed that MgAZ31-SPF-HT extracts maintained higher cell viability over 24–72 h. Gene expression analysis revealed significant downregulation of pro-inflammatory markers CTSE and TNF-α, while protein quantification via ELISA and BioPlex confirmed reduced secretion of TNF-α, TGF-β1, TGF-β2, IL-6, and IL-8, suggesting mitigation of early immune activation. Antibacterial assays demonstrated limited Staphylococcus aureus colonisation on both MgAZ31-SPF and MgAZ31-SPF-HT scaffolds, with CFU counts (~10⁵–10⁶) well below the threshold for mature biofilm formation (~10⁸), and SEM analysis confirmed sparse bacterial distribution without dense EPS-rich layers. Overall, hydrothermal treatment improves Mg alloy biocompatibility by controlling Mg²⁺ release, modulating early immune responses, and limiting bacterial adhesion, highlighting its potential to enhance clinical performance of Mg-based implants. Full article

Listeria monocytogenes (L. monocytogenes) is a major foodborne pathogen which can invade intestinal epithelial cells and cause severe systemic infection. Probiotics, as well as their surface layer proteins, hold broad promise for enhancing intestinal barrier function and defending against pathogenic invasion. In the present study, the antagonistic effects of surface layer protein ornithine carbamoyltransferase (OTC) from Enterococcus faecium (E. faecium) WEFA23 against L. monocytogenes were systematically evaluated in vitro in human intestinal epithelial Caco-2 cells, including assessments of anti-adhesion and anti-invasion capacity, inflammatory cytokine responses, intestinal barrier integrity, and transcriptomic changes, by comparing the effects of wild-type E. faecium WEFA23 and a previously constructed E. faecium WEFA23 otc gene knockout strain (E. faecium WEFA23 otc^−/−). The results demonstrated that E. faecium WEFA23 achieved significant stronger anti-adhesion and anti-invasion capacity of L. monocytogenes (p < 0.05) in the presence of OTC, potentially through increasing tight junction protein expression, regulating inflammatory cytokines, and modulating the virulence factors of the pathogen. To elucidate the potential mechanism of the inhibitory effect of OTC protein, RNA-seq was performed. The results revealed that the significantly regulated core differentially expressed genes (DEGs), including ADCY2, OARI3, CCL5, and CXCL9, were found to be involved in γ-aminobutyric acid (GABA)-ergic synapse, calcium, and toll-like receptor signaling pathways. These findings demonstrated that OTC is involved in blocking Listeria invasion and revealed the function of the OTC from E. faecium WEFA23 in antimicrobial and intestinal mucosal defense, providing a conceptual foundation for the development of new probiotic intervention strategies in anti-infection. Full article

Plant cell wall polysaccharides (PCWPs) serve as an abundant but recalcitrant carbon source for many microbes living in the gut of humans and animals. An adhesion to PCWPs is common in gut bacteria and can even be observed in the lactobacilli, which are supposed to promote the growth competence of these non-PCWP degraders because of the facilitated acquisition of newly released oligosaccharides. Nevertheless, the binding of molecules of lactobacilli to PCWPs and the underlying mechanisms remain largely unknown. By analyzing the transcriptome of Lactobacillus brevis grown in xylan supplemented with a xylanase, a gene was identified to encode a putative S-layer PCWP-binding protein (Lb1145). Lb1145 was predicted to have four domains, among which domains 1 and 2 were responsible for binding PCWPs. The binding was nonspecific, since structurally distinct PCWPs, e.g., cellulose, xylan, mannan, and chitin, and even lignin, were all bound by Lb1145. Both of the two N-terminal domains have a high pI, and we demonstrated that a non-enzymatic glycosylation-like process plays an important role in binding. Compared with another L. brevis surface protein, i.e., the WxL protein Lb630, Lb1145 displayed a binding preference for the phloem sieve tube in the wheat stem section. Moreover, Lb1145 could bind ten strains within the Lactobacillus, Enterococcus, Pediococcus, and Bacillus genera among the seventeen selected gut bacterial species. An analysis of the reported S-layer proteins from the Gram-positive bacteria (lactobacilli and bifidobacteria) and outer membrane proteins from the Gram-negative (Bacteroides fragilis and Prevotella intermedia) indicated that bacterial cell surface proteins with high pI values are not rare. The high pI-based and non-enzymatic glycosylation-like process-mediated binding represents a new paradigm and may be popular in gut bacterial surface proteins binding to PCWPs, with important physiological implications in growth competition in the gut microbiota. Full article

The ponkan (Citrus reticulata Blanco cv. Ponkan), an important citrus crop, is increasingly threatened by soil acidification. This study evaluated the efficacy of various soil amendments, including lime alone (L), lime with gypsum and organic fertilizer (LGOF), lime plus K₂CO₃ (LK), and lime with chicken manure ash (LCMA), in mitigating soil acidification and improving ponkan seedling growth. Surface-applied lime raised topsoil pH and acid buffering capacity while reducing exchangeable Al. However, combined amendments (LGOF, LK, LCMA) more effectively alleviated acidity throughout the soil profile. They significantly increased pH and buffering capacity, decreased exchangeable H and Al in the 20–40 cm layer, and elevated exchangeable base cations (K⁺, Ca²⁺, Mg²⁺). These changes reduced Al content in roots, stems, and leaves, promoted deeper root growth, and increased biomass and nutrient uptake (N, P, K). Physiologically, combined amendments enhanced photosynthetic performance (chlorophyll, Pn, ΦPSII) and increased activity of key metabolic enzymes (Rubisco, SS, SPS, NR, GS), promoting sucrose, starch, and protein accumulation. LK rapidly raised subsoil pH and potassium levels, ideal for K-deficient orchards. LGOF and LCMA improved overall fertility by supplying Ca and Mg, with LGOF additionally enhancing soil structure in poorly structured acidic soils. Full article

Sea urchin eggs are surrounded by a network of extracellular matrix, consisting of the jelly coat (JC) and vitelline layer (VL). While the voluminous JC evokes acrosomal reaction in the approaching sperm, the tight VL ensheathing the plasma membrane of the subjacent microvilli is known to be the subcellular site where ‘sperm receptors’ reside. In this study, we have examined the roles of JC and VL at fertilization in a combinatorial approach utilizing two different pretreatments of the eggs: (i) incubation with dithiothreitol (DTT) in alkaline seawater to remove JC and VL, (ii) masking the egg extracellular matrix with a carbohydrate-binding protein concanavalin A (Con A). Surprisingly, the results showed that the DTT-denuded eggs still engulfed sperm at fertilization, even more effectively than intact eggs, as multiple sperm entered. On the other hand, Con A appeared to interfere with sperm entry in a dose-dependent manner and to delay the onset of the Ca²⁺ wave in intact eggs after the cortical Ca²⁺ release, representing sperm–egg fusion. This prolonged time lag in triggering the Ca²⁺ wave at fertilization was associated with compromised dynamics of the subplasmalemmal actin filaments in Con A-pretreated eggs. By using Alexa Fluor 633 Con A and BPA-C8-Cy3, respectively, we also report unprecedented fluorescent labeling of the egg JC and the spontaneous ‘acrosomal protrusion’ on the head of Paracentrotus lividus sperm diluted in natural seawater. Combined with electron microscopy observations of intact and denuded eggs, our results suggest that the glycoconjugate on the egg surface contributes to the fertilization signal transduction, affecting the Ca²⁺ wave via actin cytoskeletal changes and sperm entry. Full article

The study of the conformational stability of protein layers at the interface between gold surfaces and lipid membranes is crucial for determining the biological activity of these systems and understanding their interactions. The surfaces differ significantly in hardness: gold is a rigid substrate, while the POPC/POPS liposome layer is highly flexible. A quartz crystal microbalance with dissipation (QCM-D) monitoring method and multi-parametric surface plasmon resonance (MP-SPR) were used to determine the adsorption efficiency of lysozymes, the level of layer hydration, and changes occurring within the secondary structure and the thickness of the formed protein layer. In both methods, lysozyme adsorption on the gold surface was more effective at pH 4.0 than at pH 7.4. The lysozyme adsorption efficiency on the surface of the lipid layer was the same for both measurement conditions. In contrast, the affinity of lysozyme molecules to the lipid surface was higher than that of the gold surface. The composition of the secondary structure of lysozymes was monitored using the FT-IR method. Deconvolution of the Amide I band confirms the existence of different mechanisms underlying lysozyme molecule immobilization depending on the type of adsorption surface. Along with the change in the surface, there is a transition from the dominance of electrostatic to hydrophobic interactions, which significantly affects the structure of the interphase layer. High content of random structures on the lipid surface is evident, while, in the case of the gold surface, there is a decrease in random structures and the presence of antiparallel β-sheets. Interaction with the surface induces the transition of amyloidogenic domains of the protein to conformations, which are particularly susceptible to aggregation, consequently leading to oligomerization. Full article

A chimeric protein of heparanase and Ig-Fc was designed as a novel tool to expand the detection of structurally heterogeneous heparan sulfate (HS) and related glycosaminoglycans. The whole mouse heparanase gene was combined with the gene segment encoding the mouse IgG1 hinge-Fc domain. A point mutation E335A was inserted to disable putative HS degradation activity. Chimeric proteins consisted of the latent form of the enzyme devoid of HS degradation activity. The chimeric proteins bound to heparin, N-desulfated heparin, and O-sulfated N-acetylheparosan. Their binding spectrum to glycosaminoglycans differed from that of anti-HS mAb 10E4. The chimeric proteins bound to Kato III and A549 cell lines. The binding was reduced by knocking down EXT1 gene expression. One of the chimeric proteins stained the epidermal cells in the hyperplastic spinous layer of inflamed atopic dermatitis skin and inflammatory cells in the dermis, which were not stained with mAb 10E4. The protein stained a polarized structure on the surface of monocytic U937 and THP1 cells. Similar polarized structures were observed with anti-syndecan-1 antibody staining. The chimeric protein and anti-syndecan-1 antibody precipitated similar sets of proteins that included syndecan-1 from the lysates of U937 cells. These novel chimeric proteins are useful to detect HS abundant in O-sulfation in histochemical, cytochemical, and biochemical studies. Full article

This study aimed to create a unique WPI film formulation that would help maintain strawberry quality. Therefore, an edible coating from WPI was developed, and its physical, mechanical, and rheological characteristics were analysed. WPI is a biopolymer residue with attractive barrier characteristics, biodegradability, and neutral taste that can be used as an edible coating on fragile fruits such as strawberries. Key innovations from this research include a comprehensive evaluation of whey as the sole polymeric component in edible coatings for strawberries, assessing its standalone protective potential; improvement of film formulation based on whey proportion; and an inferred shelf-life extension of whey-coated strawberries aligned with commercial acceptability standards, bridging the gap between research and practical application. This study showed that increasing protein proportion reduced the film’s solubility from 47.6% to 22.4%, thus enhancing its water resistance by up to 2-fold. Still, the film became tensile stiffer and more elastic modulus at 50% RH than at 70% RH. The filmogenic solution’s viscosity enhanced from 2.25 at 25 °C to 4.19 Pa.sⁿ at 4 °C, indicating homogeneous coating of the fruit surface at room temperature and its adhesion at storage temperature. During cold storage, WPI coating reduced the mass loss of strawberries from a range of 5.83–16.71% in the control to a range of 2.56–13.22%, thus decreasing the mass loss by up to 2-fold compared to uncoated fruit from the control treatment, which resulted in better visual quality and a 33% extension of the shelf life of commercial strawberries. Overall, WPI films and coatings have the potential to offer a sustainable and effective protective layer for highly perishable and delicate fruits, extending shelf life and, consequently, reducing waste. Together, these properties can revolutionise the fresh produce industry to enhance global supply chain efficiency. Full article

One of the first organisms to appear on Earth was cyanobacteria, which carried out oxygenic photosynthesis. The oxygen they produced contributed to the ozone layer’s formation. However, before this happened, cyanobacteria had to cope with various forms of radiation, including ultraviolet radiation (UVR), that reached the surface of young Earth. Billions of years ago, before the Earth’s ozone layer formed, the planet was constantly exposed to intense UVR. This radiation, especially UVB and UVC, was strong enough to break down proteins and nucleic acids. Cyanobacteria have a variety of defence mechanisms that allow them to thrive under adverse conditions. These mechanisms include the avoidance of UVR through migration or mat formation, DNA repair, antioxidant enzyme activity, and biosynthesis of UVR-absorbing compounds. Although most of today’s dangerous UVR is absorbed by the ozone layer, future space exploration has led to a closer examination of the effects of UVR, especially UVC, on various organisms, including cyanobacteria. The flexibility of cyanobacteria to tolerate unfavourable conditions makes them potential candidates for future space exploration. This brief overview provides some information on the effects of UVR on cyanobacteria, the defence mechanisms of cyanobacteria against UVR, and the potential use of cyanobacteria in life-support systems in space missions. Full article