Search Results (730)

Red deer fat makes up approximately 7–10% of the animal’s weight and is not currently used. Regarding sustainability in the food industry, it is desirable to look for opportunities for its processing and use, not only in the food industry. The aim of this study is the enzymatic modification of red deer fat, leading to modification of its physicochemical properties, and the study of changes in phase transitions of modified fat, its structure, color, and texture. Hydrolysis was performed using sn-1,3-specific lipase at different water concentrations (10–30%) and reaction times (2–6 h). The results showed that there was a significant decrease in melting and crystallization temperatures with an increasing degree of hydrolysis, which was confirmed by differential scanning calorimetry. FTIR spectra revealed a decrease in the intensity of the ester bonds, indicating cleavage of triacylglycerols. Texture analysis of the modified fats confirmed a decrease in hardness of up to 50% and an increase in spreadability. The color parameter values remained within an acceptable range. The results show that enzymatic modification is an effective tool for targeted modification of red deer fat properties, and this expands the possibilities of its application in cosmetic matrices and food applications as functional lipids. Full article

Ferulic acid (FA) is one of the most abundant hydroxycinnamic acids found in plant cell walls. Its dehydrodimers play an important role in maintaining the structural rigidity of the plant cell wall. Ferulic acid esterases (FAEs) act as debranching enzymes, cleaving the ester bond between FA and the substituted carbohydrate moieties in FA-containing polysaccharides in the plant cell wall. This enzymatic reaction facilitates the degradation of lignocellulosic materials and is crucial for the efficient utilization of biomass resources. This review focuses on the occurrence of ferulic acid in nature and its different forms and outlines the various classification systems of FAEs, their substrate specificity, and the synergistic interactions of these enzymes with other CAZymes. Additionally, it highlights the various methods that have been developed for detecting hydroxycinnamic acids and estimating the enzyme activity, as well as the versatile applications of ferulic acid. Full article

Canvas paintings are prone to biodeterioration due to their complex chemical composition, which can support fungal growth even under controlled conditions. This study evaluated the susceptibility of common synthetic restoration materials—Lascaux glues (303 HV, 498 HV), Acrylharz P550, BEVA 371, Laropal A81, and Regalrez 1094—to degradation by fourteen xerotolerant/xerophilic fungal strains. All tested Aspergillus and Penicillium species extensively colonized, especially artificially aged materials. FTIR-PAS analysis revealed chemical changes in carbonyl and C–H bonds in Laropal A81 and Regalrez 1094 colonized by Aspergillus spp. Scanning electron microscopy (SEM) imaging showed thinning of Lascaux glues and deformation of Regalrez 1094. Transcriptomic profiling of A. puulaauensis grown on Lascaux 498 HV and Regalrez 1094 identified altered expression of genes coding for esterases and oxidases, enzymes involved in synthetic polymer degradation. Esterase activity assays using 4-nitrophenol-based substrates confirmed significant enzymatic activity correlating with the presence of ester bonds. These findings highlight the vulnerability of synthetic restoration materials, specifically Laropal A81, Regalrez 1094, and Lascaux glues, to extremophilic fungi thriving in environments with low water activity. The results emphasize the urgent need for specific knowledge on fungi and their metabolic pathways to use/develop more durable conservation materials and strategies to protect cultural heritage objects from biodeterioration. Full article

Combustion of aviation jet fuel emits a complex mixture of pollutants linked to adverse health outcomes among airport personnel and nearby communities. While epidemiological studies showed the detrimental effects of aviation-derived air pollutants on human health, the molecular mechanisms of the interactions of these pollutants with cellular biomolecules like proteins that drive the adverse health effects remain poorly understood. In this study, we performed molecular docking simulations of 272 pollutant–protein complexes using AutoDock Vina 1.2.7 to characterize the binding strength of the pollutants with the selected proteins. We selected 34 aviation-derived pollutants that constitute three chemical categories of pollutants: volatile organic compounds (VOCs), polyaromatic hydrocarbons (PAHs), and organophosphate esters (OPEs). Each pollutant was docked to eight proteins that play critical roles in endocrine, metabolic, transport, and neurophysiological functions, where functional disruption is implicated in disease. The effect of binding of multiple pollutants was analyzed. Our results indicate that aliphatic and monoaromatic VOCs display low (<6 kcal/mol) binding affinities while PAHs and organophosphate esters exhibit strong (>7 kcal/mol) binding affinities. Furthermore, the binding strength of PAHs exhibits a positive correlation with the increasing number of aromatic rings in the pollutants, ranging from nearly 7 kcal/mol for two aromatic rings to more than 15 kcal/mol for five aromatic rings. Analysis of intermolecular interactions showed that these interactions are predominantly stabilized by hydrophobic, pi-stacking, and hydrogen bonding interactions. Simultaneous docking of multiple pollutants revealed the increased binding strength of the resulting complexes, highlighting the detrimental effect of exposure to pollutant mixtures found in ambient air near airports. We provide a priority list of pollutants that regulatory authorities can use to further develop targeted mitigation strategies to protect the vulnerable personnel and communities near airports. Full article

(1) Background: The urate-lowering effects of three iridoid glycosides, which are paederosidic acid, paederosidic acid methyl ester, and paederoside, isolated from Paederia foetida and the protection they provide against hyperuricemia-induced kidney injury were investigated in a rat model. (2) Methods: A hyperuricemia (HUA) rat model was established in Sprague-Dawley (SD) rats through intraperitoneal potassium oxonate (PO) and intragastrical adenine for 2 weeks. Subsequently, rats in the pharmaceutical intervention groups received corresponding drug treatments at a concentration of 40 mg/kg/day, maintained consistently for 7 days. (3) Results: The results showed that three compounds reduced serum urate (SU), creatinine (CRE), and blood urea nitrogen (BUN) levels and that the urinary excretion levels of uric acid, urine urea nitrogen, and creatinine increased. Furthermore, the administration of three iridoid glycosides enhanced renal filtration capacity, as demonstrated by the elevated 24 h creatinine clearance rate (CCR) and 24 h uric acid clearance rate (CUA); improved the fraction excretion of uric acid (FEUA); and attenuated renal damage. Finally, three iridoid glycosides promoted uric acid excretion in HUA rats by downregulating URAT1 and GLUT9 and upregulating ABCG2, OAT1, and OAT3. Moreover, the molecular docking results further corroborated the finding that the three compounds can bind to multiple sites of the uric acid transporter via hydrogen, P-π, and hydrophobic bonds. (4) Conclusions: The three iridoid glycosides were found to lower SU levels by increasing uric acid excretion. They are promising natural products for the prevention of HUA and HUA-induced kidney injury. Full article

Traditional covalently cross-linked solid-state electrolytes exhibit desirable mechanical durability but suffer from limited processability and recyclability due to their permanent network structures. Incorporating dynamic covalent bonds offers a promising solution to these challenges. In this study, we report a reprocessable and recyclable polymer electrolyte based on a dynamic ester bond network, synthesized from commercially available materials. Polyethylene glycol diglycidyl ether (PEGDE) and glutaric anhydride (GA) were cross-linked and cured in the presence of benzyl dimethylamine (BDMA), forming an ester-rich polymer backbone. Subsequently, 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) was introduced as a transesterification catalyst to facilitate network rearrangement. Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was incorporated to establish efficient ion transport pathways. By tuning the cross-linking density and catalyst ratio, the electrolyte achieved an ionic conductivity of 1.89 × 10⁻⁵ S/cm at room temperature along with excellent reprocessability. Full article

Plasma-derived fibrin hydrogels are widely used in tissue engineering because of their excellent biological properties. Specifically, human plasma-derived fibrin hydrogels serve as 3D matrices for autologous skin graft production, skeletal muscle repair, and bone regeneration. Nevertheless, for advanced applications such as in vitro skin equivalents and engineered grafts, the intrinsic limitations of native fibrin hydrogels in terms of long-term mechanical stability and resistance to degradation need to be addressed to enhance the usefulness and application of these hydrogels in tissue engineering. In this study, we chemically modified plasma-derived fibrin by incorporating succinimidyl alginate (SA), a version of alginate chemically modified to introduce reactive succinimidyl groups. These NHS ester groups (N-hydroxysuccinimide esters), attached to the alginate backbone, are highly reactive toward the primary amine groups present in plasma proteins such as fibrinogen. When mixed with plasma, the NHS groups covalently bond to the amine groups in fibrin, forming stable amide linkages that reinforce the fibrin network during hydrogel formation. This chemical modification improved mechanical properties, reduces contraction, and enhanced the stability of the resulting hydrogels. Hydrogels were prepared with a final fibrinogen concentration of 1.2 mg/mL and SA concentrations of 0.5, 1, 2, and 3 mg/mL. The objective was to evaluate whether this modification could create a more stable matrix suitable for supporting skin tissue development. The mechanical and microstructure properties of these new hydrogels were evaluated, as were their biocompatibility and potential to create 3D skin models in vitro. Dermo-epidermal skin cultures with primary human fibroblast and keratinocyte cells on these matrices showed improved dermal stability and better tissue structure, particularly SA concentrations of 0.5 and 1 mg/mL, as confirmed by H&E (Hematoxylin and Eosin) staining and immunostaining assays. Overall, these results suggest that SA-functionalized fibrin hydrogels are promising candidates for creating more stable in vitro skin models and engineered skin grafts, as well as for other types of engineered tissues, potentially. Full article

This study investigates the efficient and enantioselective hydrolysis of ester bonds through a series of biotransformations employing various photobiocatalysts. A racemic mixture of 1-phenylethyl acetate served as the model substrate. The described research identified three strains exhibiting the highest biocatalytic activity: Nostoc cf-muscorum (CCALA 129), Leptolyngbya foveolarum (CCALA 76), and Synechococcus bigranulatus (CCALA 187). Their application led to the complete hydrolysis of the starting reagent, yielding both the unreacted ester and its corresponding alcohol in an enantioselective manner. Notably, the selectivity, expressed as S, reached an impressive value of 283 in certain outcomes. The photobiotransformations were conducted under varying conditions, with particular focus on two essential parameters: the duration of the process, crucial for kinetically controlled reactions, and light exposure, critical for light-dependent organisms. The representative results highlight the efficacy of these biocatalysts. For instance, using Leptolyngbya foveolarum (CCALA 76), Nostoc cf-muscorum (CCALA 129), and Synechococcus bigranulatus (CCALA 187) facilitated the production of 1-(R)-phenylethanol with enantiomeric excesses (ee) of 89%, 88%, and 86%, respectively, at a conversion degree of approximately 50%. These processes also yielded an optically enriched mixture of the unreacted substrate, 1-(S)-phenylethyl acetate. Specifically, in the case of Leptolyngbya foveolarum (CCALA 76), the ee of the unreacted ester reached up to 98%. Light exposure emerged as a key factor influencing selectivity factor (S). Adjusting this parameter allowed us to achieve an E value of up to 283 for the formation of 1-(R)-phenylethanol with an ee > 99% when utilizing the Nostoc cf-muscorum (CCALA 129) strain. Furthermore, light intensity proved crucial for scaling up these processes. Significant results were obtained with Synechococcus bigranulatus, particularly at substrate concentrations ranging from 1 to 10 mM under limited exposure. Here, the conversion degree was 55%, the ee of the (R)-alcohol was 86%, and the selectivity factor (S) value was 21. Full article

Degradable liquid gel plugs are increasingly required for zonal isolation in high-temperature reservoirs, yet their practical deployment is limited by slow internal degradation and insufficient structural failure under diffusive conditions. In this study, a diffusion-driven degradation strategy was developed based on γ-valerolactone and a nonionic fast-penetration agent (Tb), aiming to construct internal pathways and enhance decomposability of a model E51 epoxy–anhydride liquid plug. A multiscale characterization framework, including swelling index evaluation, SEM–EDS, FTIR mapping, CLSM imaging, μ-CT, AFM, and nanoindentation, was applied to investigate degradation behavior under varying temperatures (120–140 °C) and solvent-to-plug ratios (1:1–5:1). The plug exhibited a swelling index of 1.81 in GVL and formed tree-like degradation channels with widths of 20–30 μm. Functional group mapping revealed preferential cleavage of ester and ether bonds at the surface, and mechanical softening (modulus reduction > 57%) was confirmed by AFM and nanoindentation. Higher temperatures and solvent ratios synergistically reduced full degradation time from 84 h to 12 h. These findings validate a “penetration-induced softening–ester bond scission–diffusion channel construction” mechanism, offering an effective design pathway for intelligent degradation control in high-temperature downhole environments. Full article

The Atacama Desert is emerging as an unexpected source of microbial life and, thus, a source of bioactive compounds and novel enzymes. Baeyer–Villiger monooxygenases (BVMOs), a subclass of flavin-dependent monooxygenases (FPMOs), have gained attention as promising biocatalysts for the biosynthesis of industrially relevant molecules for a wide range of applications, such as pharmaceuticals and polymers, among others. BVMOs catalyze the oxidation of ketones and cyclic ketones to esters and lactones, respectively, by using molecular oxygen and NAD(P)H. BVMOs may also catalyze heteroatoms oxidation including sulfoxidations and N-oxidations. This work aims to search for novel BVMOs in the genomes of new bacterial strains isolated from the Atacama Desert. Bioinformatic analysis led to the identification of 10 putative BVMOs, where the monooxygenase named MO-G35A was selected. Genome context showed, downstream of the MO-G35A, a gene encoding for an enzyme from the short-chain dehydrogenase/reductase family, suggesting a closer redox loop between both enzymes. MO-G35A was successfully expressed in three Escherichia coli expression systems, where higher yields were achieved using the E. coli Shuffle T7 as host, suggesting that correct disulfide bond formation is necessary for correct folding. Enzyme characterization showed that it operates optimally at 35–38 °C, exhibiting a Km of 0.06 mM and a kcat of 0.15 s⁻¹ for bicyclo [3.2.0] hept-2-en-6-one (BHC). Furthermore, the study revealed high stability in the presence of organic solvents, making it suitable for applications in various industrial processes, especially when the substrates have poor solubility in aqueous solutions. These results highlight the robustness and adaptability of enzymes in extreme environments, making them valuable candidates for biotechnological applications. Full article

Cationic surfactants, accounting for approximately 7% of the global surfactant market, are widely used in applications such as fabric softeners, biocides, and corrosion inhibitors. Recently, gemini surfactants—comprising two amphiphilic units linked by a spacer—have attracted significant interest due to their superior surface activity, lower critical micelle concentrations, and strong antimicrobial properties. However, their poor biodegradability, resulting from their complex molecular structure, has raised environmental concerns. To address this, researchers have developed ester-based gemini surfactants incorporating biodegradable bonds. This study aimed to investigate the relationship between the structure of ester-based gemini surfactants (hydrophobic chain length and spacer type) and their antimicrobial activity against bacteria and fungi. Three series of compounds featuring different functional groups in the spacer were synthesized, along with a trimeric surfactant for comparative purposes. The results demonstrated that both the hydrophobic chain length and the presence of additional cationic groups significantly influence the CMC and antimicrobial performance. Quantum mechanical calculations were also performed to search for correlations between electronic properties and chemical reactivity of compounds. These findings highlight that ester-based gemini surfactants combine high surface and antimicrobial activity with the potential for improved biodegradability, making them promising candidates for use in environmentally friendly applications. Full article

Background/Objectives: This study investigates the chemical structure and molecular interactions in 3D-printed dental resins reinforced with varying concentrations of Yttria-Stabilized Zirconia (YSZ) nanoparticles, using Fourier-Transform Infrared Spectroscopy (FTIR) to assess the compatibility and bonding behavior at the molecular level. Methods: Three groups of 3D-printed methacrylate-based resin discs were fabricated: a control (0% YSZ), and experimental groups reinforced with 1% and 3% YSZ nanoparticles. Samples were produced using Digital Light Processing (DLP) technology and post-processed under standardized conditions. FTIR spectra were collected via ATR mode over a wavenumber range of 4000–600 cm⁻¹. Spectral differences at key wavenumbers (1721.16, 1237.11, and 929.62 cm⁻¹) were statistically analyzed using one-way ANOVA and Tukey’s post hoc test. Results: FTIR spectra showed no significant shifts in the ester carbonyl band at 1721.16 cm⁻¹, suggesting the preservation of the core resin matrix. However, a statistically significant increase in absorbance at 1237.11 cm⁻¹ was observed in the 1% YSZ group (p = 0.034), indicating dipolar interaction. A distinct new peak at 929.62 cm⁻¹, corresponding to Zr–O vibrations, emerged in the 3% YSZ group (p = 0.002), confirming successful nanoparticle integration. Conclusions: YSZ nanoparticles enhance specific molecular interactions within methacrylate-based dental resins without compromising structural integrity. These findings support the potential application of YSZ-reinforced 3D-printed resins in durable, biocompatible permanent dental restorations. Full article

Phospholipase A₂ (PLA₂) is a prevalent molecule in the honeybee venom. Its importance is reflected by the number of scientists focused on studying it from various points of view. This review summarises a significant amount of data concerning this fascinating substance. Firstly, the origin and occurrence of PLA₂, with similarities and differences among species or populations of bees are highlighted. Next, its synthesis, post-translational processing and structural features are described, followed by the PLA₂ availability. In a larger section, the multiple effects of honeybee venom PLA₂ are detailed, starting with the main ability as an enzyme to interact with biological membranes and to hydrolyse the sn-2 ester bond in 1,2-diacyl-sn-3-phosphoglycerides; the docking process, the substrate binding and the catalytic steps are analysed too. Then, the pro-/anti-inflammatory effect and allergenic property, the anticoagulant effect and the involvement of PLA₂ in apoptosis are revised. Selected antiviral, antibiotic and antitumoral effects of PLA₂, as well as its use in immunotherapy are mentioned as beneficial applications. Additionally, the mechanisms of toxicity of PLA₂ are presented in detail. Finally, a number of anti-PLA₂ compounds are enumerated. In each section, the features of the honeybee venom molecule are discussed in relation to PLA₂s from other species. Full article

Over the past two decades, the copper(I)-catalyzed azide–alkyne 1,3-dipolar cycloaddition (CuAAC), commonly known as click chemistry, and C–H bond activation have gained significant attention and have emerged as key synthetic methodologies. In our efforts to synthesize fused nitrogen-containing heterocycles, we developed a palladium-catalyzed protocol for the synthesis of functionalized 7,10-dihydropyrrolo[3,2,1-ij][1,2,3]triazolo[4,5-c]quinolines and 5,8-dihydrobenzo[3,4][1,2,3]triazolo[4′,5′:5,6]azepino[1,2-a]indoles from suitable bromo-substituted N-propargyl-indoles. The reaction conditions demonstrate broad functional group compatibility including halogen, alkoxyl, cyano, ketone, and ester, affording the target compounds in good to high yields. Full article

To investigate the microscopic mechanism of aging-induced “dewetting” at the matrix/filler interface in Nitrate Ester Plasticized Polyether (NEPE) propellant, this study decoupled the aging process into two factors: crosslinking density evolution and nitrate ester decomposition. Molecular dynamics (MD) simulations were employed to construct all-component matrix models and matrix/filler interface models with varying aging extents. Key parameters including crosslinking density, mechanical properties, free volume fraction, diffusion coefficients of the matrix, as well as interfacial binding energy and radial distribution function (RDF) were calculated to analyze the effects of both aging factors on “debonding”. The results indicate the following: 1. Increased crosslinking density enhances matrix rigidity, suppresses molecular mobility, and causes interfacial binding energy to initially rise then decline, peaking at 40% crosslinking degree. 2. Progressive nitrate ester decomposition expands free volume within the matrix, improves binder system mobility, and weakens nitrate ester-induced interfacial damage, thereby strengthening hydrogen bonding and van der Waals interactions at the interface. 3. The addition of a small amount of bonding agent improved the interfacial bonding energy but did not change the trend of the bonding energy with aging. Full article