Search Results (227)

Background: N^ε-(carboxymethyl)-lysine (CML) is formed in the human body by non-enzymatically driven reactions including glycation, oxidation, and lipoxidation. CML is a ubiquitous product of normal physiology, but its levels are increased under disease conditions like chronic kidney disease (CKD) and diabetes mellitus (DM). Free CML is eliminated from the human body mainly through kidney excretion, and its accumulation in the kidney tissue is linked to CKD pathogenesis. Aim: The main goal of this study was to evaluate the relative contribution of CKD and Type 2 DM (T2DM) to the accumulation of CML in patients’ sera. Methods: The study included 22 patients with CKD without DM, 55 with CKD and comorbid T2DM, and 21 with T2DM without CKD. Serum CML levels were measured by ELISA. The Kruskal-Wallis test was used to detect differences among groups. Spearman correlation analysis was performed, and the one-tailed Dunn test was considered to indicate statistical significance at p < 0.05. Results: The median serum CML levels (CKD, 658.4 ± 434.3 ng/mL; CKD + T2DM, 431.3 ± 327.9 ng/mL; T2DM, 273.9 ± 134.2 ng/mL) differed significantly (p < 0.05) among the three patient groups. A positive correlation was observed between serum CML and microalbuminuria (p = 0.004; r = 0.58), proteinuria (p = 0.002; r = 0.6), and age (p = 0.007; r = 0.52) only in the CKD patients. In all T2DM patients, independent of CKD status, serum CML correlated negatively (p < 0.05) with postprandial glucose and duration of diabetes, while its correlation with fasting glucose and HbA1c was negative only in the T2DM cohort without CKD. Conclusions: In patients with CKD, higher levels of CML were observed compared to those with T2DM. Serum CML correlated positively with proteinuria, albuminuria, and patient age in non-diabetic CKD patients, and negatively with blood glucose, HbA1c, and DM duration of T2DM in patients without CKD. Full article

Background: This study is the first to investigate the association between colorectal cancer (CRC) risk and the hMLH1 −93G>A and hMSH2 1032G>A polymorphisms of mismatch repair (MMR) genes in the Azerbaijani population. Methods: Peripheral blood samples containing EDTA were collected from the study subjects (134 patients and 137 controls), and genomic DNA was extracted using the non-enzymatic salting-out method. Genotypes were determined by polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP), and the results were visualized through agarose gel electrophoresis. Results: Overall, no statistically significant correlation was observed between CRC risk and the hMLH1 −93G>A polymorphism in the heterozygous GA (OR = 0.760; 95% CI = 0.374–1.542; p = 0.446), the mutant AA (OR = 1.474; 95% CI = 0.738–2.945; p = 0.270), or the A allele (OR = 1.400; 95% CI = 0.984–1.995; p = 0.062). However, in contrast to the dominant model, a statistically significant association was found between the recessive model and an increased CRC risk, with an odds ratio of 1.788 (95% CI = 1.102–2.900; p = 0.018). The hMLH1 −93G>A polymorphism was identified at a significantly higher frequency across the TNM stages, with the distribution showing statistical significance (p < 0.05). Additionally, no statistically significant association was observed between the hMSH2 1032G>A polymorphism and CRC risk. Conclusions: Although no overall association was observed for hMLH1 −93G>A, our findings suggest a potential link with increased colorectal cancer risk under the recessive model in the Azerbaijani population. Further studies are warranted to confirm this model-specific association and investigate the underlying biological mechanisms. Full article

Creatinine serves as a crucial diagnostic biomarker for assessing kidney disease. This work developed portable non-enzymatic and multienzyme-modified electrochemical biosensors for the detection of creatinine based on commercial screen-printed carbon electrodes (SPCEs). The non-enzymatic creatinine sensor was constructed by the electrochemical deposition of AuNPs onto the surface of a pre-activated SPCE by electrochemical activation, followed by the surface modification of a Nafion membrane. The developed AuNPs/SCPE exhibited excellent reproducibility, and the proposed Nafion/AuNPs/SPCE sensor showed excellent detection sensitivity and selectivity toward creatinine. In comparison, the enzymatic creatinine biosensor was gradually established by the electrodeposition of a Prussian blue (PB) membrane on the optimal AuNPs/SCPE surface, followed by multi-enzyme cascade modification (which consisted of creatinine amidohydrolase (CA), creatine oxidase (CI) and sarcosine oxidase (SOx)) and drop-casting the Nafion membrane to stabilize the interface. The introduction of a PB interlayer acted as the redox layer to monitor the generation of hydrogen peroxide (H₂O₂) produced by the enzymatic reaction, while the Nafion membrane enhanced the detection selectivity toward creatine, and the multi-enzyme cascade modification further increased the detection specificity. Both non-enzymatic and enzymatic creatinine sensors could detect the lowest concentrations of less than or equal to 10 μM. In addition, the efficiency and reproducibility of the proposed composite biosensor were also confirmed by repetitive electrochemical measurements in human serum, which showed a positive linear calibration relation of peak currents versus the logarithm of the concentration between 10 μM and 1000 μM, namely, i_p (μA) = −7.06 lgC (μM) −5.30, R² = 0.996. This work offers a simple and feasible approach to the development of enzymatic and non-enzymatic creatinine biosensors. Full article

In this study, a simple, mild, and eco-friendly cold plasma-solution interaction method is employed to rapidly prepare gold colloids. Through modification with multi-walled carbon nanotubes (MWCNTs), a non-enzymatic glucose-sensing electrode material is successfully fabricated. The prepared electrode material is characterized via X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The results show that compared with the chemically reduced AuNPs-C-MWCNTs, the plasma-prepared AuNPs-P-MWCNTs exhibits enhanced glucose catalytic performance with a higher sensitivity of 73 μA·mM⁻¹·cm⁻² (approximately 3.2 times that of AuNPs-C-MWCNTs), lower response time of 2.1 s, and ultra-low detection limit of 0.21 μM. It also demonstrates excellent selectivity, reproducibility (RSD = 4.37%), repeatability (RSD = 3.67%), and operational stability (RSD = 4.51%). This improvement can be attributed to the smaller particle size and better dispersion of plasma-derived AuNPs on the surface of MWCNTs. Furthermore, the AuNPs-P-MWCNTs surface is enriched with oxygen-containing functional groups, which is conducive to the enhancement of the hydrophilicity of the electrode surface. These synergistic effects facilitate the AuNPs-catalyzed glucose oxidation reaction, ultimately leading to superior glucose catalytic performance. Full article

During processing and storage, vegetables often experience undesirable color changes, including fading, lightening, or yellowing and softening, due to browning (enzymatic and non-enzymatic) and chlorophyll degradation. These changes diminish commercial and nutritional value. Therefore, it is necessary to maintain vegetable color and improve the quality of vegetable-based dishes. To address these issues, it is a scientific and practical necessity to summarize and discuss existing strategies and innovative techniques. This review first highlights the mechanisms of vegetable browning. This review then provides a comprehensive overview of recent advances in methods for color preservation, focusing on underlying mechanisms and techniques for inhibiting color changes from physical, chemical, and biological perspectives. A review of innovative technologies suggests that effective color preservation in vegetables is achieved by inhibiting the conditions that lead to three unfavorable color change reactions: enzymatic browning, non-enzymatic browning, and chlorophyll degradation. Current research frequently employs combined approaches that integrate two or more techniques to mitigate these adverse color changes. Moreover, most of these methods could simultaneously inhibit the three reaction processes. Future research directions are proposed for in-depth investigations into the molecular mechanisms of color changes in vegetables and the impact of treatments on the nutritional value. Full article

A subject of increasing fundamental and technological interest is the techno- and bio-functionality of functional foods and nutraceuticals in high-solid gels. This encompasses the diffusion of natural bioactive compounds, prevention of oxidation of essential fatty acids, minimization of food browning, and the prevention of malodorous flavour formation in enzymatic and non-enzymatic reactions, to mention but a few. Textural and sensory considerations require that these delivery/encapsulating/entrapping vehicles are made with natural hydrocolloids and co-solutes in a largely amorphous state. It is now understood that the mechanical glass transition temperature is a critical consideration in monitoring the performance of condensed polymer networks that incorporate small bioactive compounds. This review indicates that the metastable properties of the rubber-to-glass transition in condensed gels (as opposed to the thermodynamic equilibrium in crystalline lattices) are a critical parameter in providing a fundamental quality control of end products. It appears that the “sophisticated synthetic polymer research” can provide a guide in the design of advanced biomaterials for targeted release or the prevention of undesirable byproducts. Such knowledge can assist in designing and optimizing functional foods and nutraceuticals, particularly those including vitamins, antioxidants, essential fatty acids, stimulants for performance enhancement, and antimicrobials. Full article

The Maillard reaction is a complex chemical reaction that occurs between nucleophilic groups, such as thiolates or amino groups primarily from amino acids, peptides, proteins, and carbonyl groups, particularly from reducing sugars. The pH value of the medium is a key parameter controlling the kinetics of the Maillard reaction, as it influences the concentration of nucleophilic groups. Other specific conditions of reaction medium such as temperature, reaction time (or residence time in a process), and water activity also significantly influence the Maillard reaction. Understanding the impact of these parameters is essential for optimizing the Maillard reaction to enhance sensory attributes, nutritional qualities, and product stability during the storage and distribution of the final products. The Maillard reaction is responsible for the formation of desirable sensory qualities such as flavor, aroma, color, and texture in cooked and thermally processed foods, in addition to the improvement of nutritional value and shelf life of foods. In contrast, there are limitations in its industrial applications, as it can also generate harmful compounds such as acrylamide, N(6)-carboxymethyllysine, furans, and heterocyclic amines, as well as undesired changes in the nutritional value of the food. This review provides an overview of the Maillard reaction’s mechanism, influencing parameters, pros and cons, as well as some food industrial applications. Full article

Glycation influences skin aging through non-enzymatic reactions between reducing sugars and proteins, forming advanced glycation end-products (AGEs) that accelerate skin deterioration. This study evaluates the curative anti-glycation effects of an injectable formulation combining dual-molecular-weight hyaluronic acid (low and mid/high) with trehalose in methylglyoxal-induced glycation in human skin explants. Thirty-six human skin explants were allocated across five experimental groups in a 12-day study. Glycation was induced using methylglyoxal (500 μM) on days 1 and 4, followed by curative product administration on day 5. CML (Nε-(carboxymethyl)lysine) immunohistochemistry was performed to assess glycation levels in the reticular dermis at days 6, 8, and 12, with quantitative analysis conducted through standardized image analysis. The formulation significantly reduced CML formation by 60% on day 6 compared to untreated controls (p < 0.001). Under methylglyoxal-induced glycation stress the product showed sustained curative effects, with CML reductions of 69% on day 6 (p = 0.008), 68% on day 8 (p = 0.012), and 61% on day 12 (p = 0.033) compared to methylglyoxal treatment alone. Cell viability remained unaffected throughout the study period across all experimental conditions. The tested injectable formulation exhibits significant and sustained curative anti-glycation properties in human skin explants for 12 days, effectively counteracting methylglyoxal-induced glycation damage without affecting cell viability. These findings advance anti-aging skin interventions, offering a novel approach to address glycation-induced skin damage with potential applications in clinical dermatology and aesthetic medicine. Full article

Background: Mesenchymal stem cell-based therapy may be indicated in ischaemic heart disease. The use of autologous adipose-derived mesenchymal stromal cells (AdMSCs) offers regenerative potential due to their paracrine effects. The aim of this study was to expand and characterise adult human thymus-derived MSCs harvested during open heart surgery with respect to their stem cell and paracrine properties. Methods: Enzymatically and non-enzymatically isolated human thymic AdMSCs (ThyAdMSCs) were cultured in xeno-free media containing pooled human platelet lysate (pPL). MSC characterisation was performed. Ex vivo expanded ThyAdMSCs were differentiated into three lineages. Proliferative capacity and immunomodulatory properties were assessed by proliferation assays and mixed lymphocyte reaction, respectively. Gene expression analysis was performed by qPCR. Results: Both isolation methods yielded fibroblast-like cells with plastic adherence and high proliferation. Flow cytometry revealed distinct expression of MSC markers in the absence of haematopoietic cell surface markers. Ex vivo expanded ThyAdMSCs could be differentiated into adipocytes, osteocytes, and chondrocytes. Activated peripheral blood mononuclear cells were significantly reduced when co-cultured with ThyAdMSCs, indicating their ability to inhibit immune cells in vitro. Gene expression analysis showed significantly less IFNγ and TNFα, indicating an alteration of the activated and pro-inflammatory state in the presence of ThyAdMSCs. Conclusions: These results demonstrate an efficient method to generate AdMSCs from human thymus. These MSCs have a strong immunomodulatory capacity and are, therefore, a promising cell source for regenerative medicine. The culture conditions are crucial for cells to proliferate in culture. Further research could explore the use of ThyAdMSCs or their secretome in surgical procedures. Full article

Surimi gel, a type of hydrocolloidal food, is formed through the gelation of fish meat proteins. Myosin heavy chain (MHC), a key myofibrillar protein, plays a crucial role in the formation of the gel network via both transglutaminase (TGase)-catalyzed and non-enzymatic polymerization. Gel disintegration in surimi is primarily attributed to the proteolytic degradation of MHC. This study focused on golden threadfin bream Nemipterus virgatus, a species characterized by low TGase activity and high protease activity at elevated temperatures. We investigated the competition between non-enzymatic polymerization and proteolytic degradation of MHC and their effects on gel mechanical properties using a mathematical model. A mathematical model based on kinetic reactions accurately reflected the changes in MHC observed through SDS-PAGE analysis during N. virgatus gel disintegration. Our results indicate that not only unpolymerized but also polymerized MHC was significantly degraded, which substantially contributed to the reduction in the mechanical properties of the N. virgatus surimi. Mathematically understanding the dynamics of MHC in surimi during heating helps promote the utilization of noncommercial fish species for surimi processing by enabling better control over surimi gel properties. Full article

Metabolism, the network of biochemical reactions that powers life, arose under conditions radically different from those on Earth today. Investigating its origins reveals how initially simple chemical processes gradually integrated nucleic acid and then protein catalysts, becoming progressively more complex and regulated until they evolved into the enzyme-rich systems observed in modern organisms. Here, we integrate multiple perspectives on the origin of metabolism, focusing primarily on an evolutionary trajectory from an RNA-based world, where ribozymes, metal ions, coenzymes, small peptides, and other small organic molecules worked in concert, to enzyme-driven metabolic networks. We also address the longstanding debates on whether these early metabolic pathways were largely autotrophic or heterotrophic, and consider so-called “pre-metabolisms” (non-enzymatic networks) as an alternative conceptual framework. We discuss key examples such as the Wood–Ljungdahl (W–L) pathway and the reverse tricarboxylic acid (TCA) cycle, both posited to function under early Earth conditions. Finally, we examine how the environment (e.g., minerals, clays, hydrothermal vents) shaped early metabolism, describe unresolved questions about the Last Common Ancestor’s catalytic repertoire and propose future directions that link geochemical insights with molecular biology and synthetic approaches. Full article

Glyoxal (GO) is a reactive dicarbonyl derived endogenously from sugars and other metabolic reactions within cells. Numerous exogenous sources of this compound include tobacco smoking, air pollution, and food processing. GO is toxic to cells mainly due to its high levels and reactivity towards proteins, lipids, and nucleic acids. We speculate that glyoxal could be involved in erythrocyte protein damage and lead to cell dysfunction. The osmotic fragility and level of amino and carbonyl groups of membrane proteins of erythrocytes incubated for 24 h with GO were identified. The amount of thiol, amino, and carbonyl groups was also measured in hemolysate proteins after erythrocyte treatment with GO. In hemolysate, the level of glutathione, non-enzymatic antioxidant capacity (NEAC), TBARS, and activity of antioxidant enzymes was also determined. The study’s results indicated that GO increases erythrocyte osmotic sensitivity, alters the levels of glutathione and free functional groups in hemolysate proteins, and modifies the activity of antioxidant enzymes. Our findings indicate that GO is a highly toxic compound to human erythrocytes. Glyoxal at concentrations above 5 mM can cause functional changes in erythrocyte proteins and disrupt the oxidoreductive balance in cells. Full article

Advanced glycation end products (AGEs) are a group of compounds formed through non-enzymatic reactions between reducing sugars and proteins, lipids, or nucleic acids. AGEs can be generated in the body or introduced through dietary sources and smoking. Recent clinical and animal studies have highlighted the significant role of AGEs in various health conditions. These compounds accumulate in nearly all mammalian tissues and are associated with a range of diseases, including diabetes and its complications, cardiovascular disease, and neurodegeneration. This review summarizes the major diseases linked to AGE accumulation, presenting both clinical and experimental evidence. The pathologies induced by AGEs share common mechanisms across different organs, primarily involving oxidative stress, chronic inflammation, and direct protein cross-linking. Interventions targeting AGE-related diseases focus on inhibiting AGE formation using synthetic or natural antioxidants, as well as reducing dietary AGE intake through lifestyle modifications. AGEs are recognized as significant risk factors that impact health and accelerate aging, particularly in individuals with hyperglycemia. Monitoring AGE level and implementing nutritional interventions can help maintain overall health and reduce the risk of AGE-related complications. Full article

This study seeks to develop and implement a non-enzymatic fluorescent labeling for immunoassay and immunochromatographic assay (ICAs) targeting SARS-CoV-2, to meet the extensive interest and need for effective COVID-19 diagnosis. In this manuscript, we delineate the development, synthesis, and evaluation of a novel quinone polymer zinc hybrid nanoarchitecture, referred to as polymerized alizarin red–inorganic hybrid nanoarchitecture (PARIHN), which integrates an antibody for direct use in fluorescent immunoassays, offering enhanced sensitivity, reduced costs, and improved environmental sustainability. The designed nanoarchitecture can enhance the sensitivity of the immunoassay and enable rapid results without the complexities associated with enzymes, such as their low stability and high cost. At first, a chitosan–alizarin polymer was synthesized utilizing quinone–chitosan conjugation chemistry (QCCC). Then, the chitosan–alizarin polymer was embedded with the detection antibody using zinc ion, forming PARIHN, which was proven to be a stable label with the ability to enhance the assay stability and sensitivity of the immunoassay. PARIHN can react with phenylboronic acid (PBA) or boric acid through its alizarin content to produce fluorescence signals with an LOD of 15.9 and 2.6 pm for PBA and boric acid, respectively, which is the first use of a boric acid derivative in signal generation in the immunoassay. Furthermore, PARIHN demonstrated high practicality in detecting SARS-CoV-2 nucleoprotein in fluorescence (PBA and boric acid) systems with an LOD of 0.76 and 10.85 pm, respectively. Furthermore, owing to the high brightness of our PARIHN fluorogenic reaction, our labeling approach was extended to immunochromatographic assays for SARS-CoV-2 with high sensitivity down to 9.45 pg/mL. Full article

Peony mead, an emerging fermented beverage, has attracted attention because of its unique flavor and health benefits. The dynamic changes in sensory quality and the molecular mechanisms involved during post-fermentation are still unclear, limiting its industrial production. In this study, GC-IMS (gas chromatography-ion mobility spectrometry) and UHPLC-MS/MS (ultrahigh-performance liquid chromatography–tandem mass spectrometry) were employed to systematically analyze the variations in aroma and quality of peony mead across aging stages. During the aging process, titratable acid content increased significantly, while soluble solids and reducing sugars decreased. Total phenol content initially rose but subsequently declined. Sensory analysis demonstrated that the sweet–acid balance and polyphenol content were critical in shaping the sensory characteristics of the product. Seventeen key volatile metabolites were identified via GC-IMS, with the 2-methyl-1-propanol dimer/polymer and 3-methyl-1-butanol dimer/polymer serving as potential characteristic markers. These key volatile metabolites underwent physicochemical reactions, yielding complex and coordinated aroma characteristics. UHPLC–MS/MS analysis revealed that nonvolatile metabolites changed significantly, which were driven by nonenzymatic reactions such as redox reactions, hydrolysis, and condensation. In addition, correlation analysis identified mechanisms by which key metabolites potentially contributed to sensory properties such as floral aroma, fruit fragrance, sweetness, sourness, etc. This study provided insights into quality changes during aging and supported the development of high-quality fermented beverages. Full article