Search Results (62)

This work reviews the complex role of the enzyme triosephosphate isomerase (TIM) (EC 5.3.1.1) within the context of diabetes, a prevalent metabolic disorder. It summarizes the main biochemical pathways, cellular mechanisms, and molecular interactions that highlight both the function of TIM and its implications in diabetes pathophysiology, particularly focusing on its regulatory role in glucose metabolism and insulin secretion. TIM’s involvement is detailed from its enzymatic action in glycolysis, influencing the equilibrium between dihydroxyacetone phosphate and glyceraldehyde-3-phosphate, to its broader implications in cellular metabolic processes. The article highlights how mutations in TIM can lead to metabolic inefficiencies that exacerbate diabetic conditions. It discusses the interaction of TIM with various cellular pathways, including its role in the ATP-sensitive potassium channels in pancreatic beta cells, which are crucial for insulin release. Moreover, we indicate the impact of oxidative stress in diabetes, noting how TIM is affected by reactive oxygen species, which can disrupt normal cellular functions and insulin signaling. The enzyme’s function is also tied to broader cellular and systemic processes, such as membrane fluidity and cellular signaling pathways, including the mammalian target of rapamycin, which are critical in the pathogenesis of diabetes and its complications. This review emphasizes the dual role of TIM in normal physiological and pathological states, suggesting that targeting TIM-related pathways could offer novel therapeutic strategies for managing diabetes. It encourages an integrated approach to understanding and treating diabetes, considering the multifaceted roles of biochemical players such as TIM that bridge metabolic, oxidative, and regulatory functions within the body. Full article

In this study, we investigated the dynamic changes in muscle lipid content (MLC) deposition in the breast muscle of Jingyuan chickens at different stages (42-, 126-, and 180- days old) using metabolomics. The pH_45min, a*, and L* were significantly increased in the breast muscle of 126-day-old chickens, and MLC and b* were significantly increased in the breast muscle of 180-day-old chickens. A total of 4643 differentially expressed metabolites (DEMs) were identified, of which 10 decreased and 29 increased with age. Key pathways associated with meat quality traits included oxidative phosphorylation, β-alanine metabolism, and glycerophospholipid metabolism. Combined transcriptomic and phenotypic correlation analyses revealed significant positive correlations of MLC, pH_45min, a*, and L* with LysoPC 20:4, CD3E, TARP, IL7R, ENSGALG00010025331, and RASSF5. In the 42- and 180-day-old chickens, MLC, pH_45min, a*, and L* were significantly and positively correlated with L-Anserine, Dihydroxyacetone phosphate, ENSGALG00010006904, and HSPB7. MLC, pH_45min, a*, and L* were significantly and positively correlated with beta-Nicotinamide adenine dinucleotide in the 126- and 180-day-old chickens. This study deepens our understanding of the differences in MLC deposition at different stages of Jingyuan chickens and its relationship with meat quality traits. Full article

In this study, we optimized the initial concentrations of glycerol and (NH₄)₂SO₄ to enhance 1,3-propanediol (1,3-PDO) production by Clostridium beijerinckii strain Br21. A central composite rotational design (CCRD) was employed, varying glycerol concentrations between 158 and 441 mmol L⁻¹, and (NH₄)₂SO₄ concentrations between 4.4 and 25.8 mmol L⁻¹. The CCRD identified optimal conditions at 441.42 mmol L⁻¹ for glycerol and 25.8 mmol L⁻¹ for (NH₄)₂SO₄. The optimized medium resulted in a 112% increase in 1,3-PDO production compared to the original medium. Analysis of NH₄⁺ and SO₄²⁻ ions under optimal conditions revealed a higher consumption of NH₄⁺ than SO₄²⁻. Furthermore, a quantitative gene expression analysis revealed that while the expression of genes responsible for glycerol uptake and ATP sulfurylase remained unchanged, the expression of the dhaM gene, which encodes the oxidative phosphoenolpyruvate:dihydroxyacetone phosphotransferase, increased approximately 6-fold. In the reductive pathway, the expression of the dhaB1 gene, encoding glycerol dehydratase, and the dhaT gene, encoding 1,3-propanediol dehydrogenase, increased 2.5- and 5-fold, respectively. The upregulation of these genes supports the hypothesis that the optimal concentrations of glycerol and (NH₄)₂SO₄ enhance the 1,3-PDO production by C. beijerinckii Br21. Full article

The oxidation of glycerol offers a valuable route for producing high-value chemicals. This review provides an in-depth analysis of the current advancements and mechanistic insights into novel metal-based catalysts for glycerol oxidation. We discuss the catalytic roles of both precious metals (e.g., Pt, Pd, Au), noted for their high efficiency and selectivity, and cost-effective alternatives, such as Ni, Cu, and Fe. Bimetallic and metal oxide catalysts are highlighted, emphasizing synergistic effects that enhance catalytic performance. This review elucidates the key mechanism involving selective adsorption and oxidation, providing detailed insights from advanced spectroscopic and computational studies into the activation of glycerol and stabilization of key intermediates, including glyceraldehyde and dihydroxyacetone. Additionally, selective carbon–carbon bond cleavage to yield smaller, valuable molecules is addressed. Finally, we outline future research directions, emphasizing the development of innovative catalysts, deeper mechanistic understanding, and sustainable process scale-up, ultimately advancing efficient, selective, and environmentally friendly catalytic systems for glycerol valorization. Full article

The modification of catalytic activity through the use of metallic promoters is a key strategy for optimizing performance, as electronic factors play a crucial role in regulating catalytic behavior. This study explores the electronic factors behind the adsorption of glycerol (Gly) on bimetallic nickel-based compounds (${\mathrm{Ni}}_3\mathrm{X}$) using density functional theory (DFT) calculations; incorporating Mn, Fe, Co, Cu, and Zn as promoters effectively tunes the d-band center of these systems, directly influencing their magnetic, adsorption, and catalytic properties. A good correlation between the calculated glycerol adsorption energy and the d-band filling of the studied bimetallic surfaces was identified. Interestingly, this correlation can be rationalized using the celebrated Newns–Anderson model based on the calculated d-band fillings and centers of the systems under study. Additionally, the adsorption energies and relative stability of other electro-oxidation intermediates toward dihydroxyacetone (DHA) were calculated. Notably, the ${\mathrm{Ni}}_3\mathrm{Co}$ and ${\mathrm{Ni}}_3\mathrm{Cu}$ systems exhibit an optimal balance between glycerol adsorption and DHA desorption, making them promising candidates for glycerol electro-oxidation. These theoretical insights address fundamental aspects of developing glycerol valorization processes and advancing alcohol electro-oxidation technologies in fuel cells with noble-metal-free catalysts. Full article

Corncobs are a widespread and renewable by-product of corn cultivation that are typically considered waste or low-value material. Corncobs contain hemicellulose, cellulose, and lignin, which can be converted into valuable products using suitable techniques. Subcritical water is increasingly used as a green medium for the extraction of valuable components from biomass, as it has many advantageous properties (high yield, pure extracts, shorter times) compared to other organic solvents. For this reason, subcritical water was used in this study to extract valuable components from corncobs at different temperatures (150–250 °C) and reaction times (10–60 min). During the decomposition of corncobs, numerous valuable products are formed in the aqueous phase depending on the temperature and reaction time. In addition to sugars and their derivatives, phenolic compounds were also formed, which are of great importance in numerous applications. It was found that at low temperatures (150–170 °C) the hemicellulose in the corncobs begins to decompose and, in particular, the sugars (glucose, xylose, arabinose, and galactose) are initially formed in the aqueous phase. Higher temperatures (200 and 250 °C) are more favorable for the decomposition of corncobs into valuable components. The yield of sugars increases with temperature due to the degradation of the cellulose content of the lignocellulosic biomass. At the same time, several new valuable products (furfural, 5-hydroxymethylfurfural (5-HMF), 1,3-dihydroxyacetone, levulinic acid, and formic acid as well as phenolic components) are formed through the degradation of lignin and the further degradation of sugars. The most important products are certainly the furfurals, which are central platform compounds. The highest furfural content was reached at 200 °C and 60 min and accounted for almost half of all components in the aqueous phase (472.01 ± 5.64 mg/g dry extract). These biomass-derived sugars and derivatives can be used in the production of fuels, pharmaceuticals, biodegradable polymers, and surfactants. Full article

Formolase, a thiamine pyrophosphate (TPP)-dependent enzyme, catalyzes the carboligation of three one-carbon formaldehyde molecules into one three-carbon dihydroxyacetone molecule. It has many important functions in the biosynthesis of carbon-based compounds and utilization of CO₂. However, the enzyme has low activity and stability in the catalytic process, resulting in high cost in the applications. To improve the stability, formolase was immobilized onto magnetic nanoparticles, which were designed to have functional epoxy groups for covalently binding the enzyme. In the immobilization, effects of pH, temperature, and cofactor TPP on the immobilization were investigated and optimized. The results showed that the retention activity of immobilized formolase was highly related to TPP. In the presence of TPP, the specific activity of the immobilized formolase was 6.8 times higher than that without TPP. The optimal immobilization conditions were as follows: a temperature of 20 °C, a pH of 7.0, an immobilization time of 8 h, and an enzyme loading of 20 mg/g. Molecular docking was used to analyze the effect of TPP on the stabilization of the enzyme in the immobilization, which indicated that TTP could stabilize the enzyme structure during the immobilization. The stabilization effect of TPP could be a reference in the immobilization of other enzymes with TPP as the cofactor. Full article

The aim of this research was to design and synthesize new lipid conjugates of 7-DHC that could serve as a new storage form of esterified provitamin D₃, increasing the reservoir of this biomolecule in the epidermis and enabling controlled production of vitamin D₃ even during periods of sunlight deficiency. Acylglycerol and glycerophospholipid containing succinate-linked provitamin D₃ at the sn-2 position of the glycerol backbone were synthesized from dihydroxyacetone (DHA) and sn-glycerophosphocholine (GPC), respectively. The three-step synthesis of 1,3-dipalmitoyl-2-(7-dehydrocholesterylsuccinoyl)glycerol involved the esterification of DHA with palmitic acid, reduction of the carbonyl group, and conjugation of the resulting 1,3-dipalmitoylglycerol with 7-dehydrocholesterol hemisuccinate (7-DHC HS). The use of NaBH₃CN as a reducing agent was crucial to avoid acyl migration and achieve the final product with 100% regioisomeric purity. For the preparation of 1-palmitoyl-2-(7-dehydrocholesterylsuccinoyl)-sn-glycero-3-phosphocholine, a two-step process was applied, involving the esterification of GPC at the sn-1 position with palmitic acid, followed by the conjugation of 1-palmitoyl-sn-glycero-3-phosphocholine with 7-DHC HS. Alongside the main product, a small amount of its regioisomer with provitamin D₃ linked at the sn-1 position and palmitic acid at the sn-2 position was detected, indicating acyl migration from the sn-1 to the sn-2 position in the intermediate 1-palmitoyl-sn-glycerophosphocholine. The synthesized novel lipids were fully characterized using spectroscopic methods. They can find applications as novel lipid-based prodrugs as additives to sunscreen creams. Full article

The growing demand for sustainable chemical production has spurred significant interest in biocatalysis. This study is framed within the biocatalytic production of 1,3-dihydroxyacetone (DHA) from glycerol, a byproduct of biodiesel manufacturing. The main goal of this study is to address the challenge of identifying the optimal operating conditions. To achieve this, catalytic potential, a lumped parameter that considers both the activity and stability of immobilized biocatalysts, was used to guide the design of a multi-enzymatic system. The multi-enzymatic system comprises glycerol dehydrogenase (GlyDH) and NADH oxidase (NOX). The enzymatic oxidation of glycerol to DHA catalyzed by GlyDH requires the cofactor NAD+. The integration of NOX into a one-pot reactor allows for the in situ regeneration of NAD+, enhancing the overall efficiency of the process. Furthermore, immobilization on Ni⁺² agarose chelated supports, combined with post-immobilization modifications (glutaraldehyde crosslinking for GlyDH), significantly improved the stability and activity of both enzymes. The catalytic potential enabled the identification of the optimal operating conditions, which were 30 °C and pH 7.5, favoring NOX stability. This work establishes a framework for the rational design and optimization of multi-enzymatic systems. It highlights the crucial interplay between individual enzyme properties and process conditions to achieve efficient and sustainable biocatalytic transformations. Full article

The chemical composition of Sedum ewersii Ledeb., a plant indigenous to Kazakhstan and traditionally utilized in folk medicine, was comprehensively investigated, with a focus on its various plant parts. Fresh samples collected in May 2023 from the Almaty region underwent hydrodistillation to extract volatile components, followed by analysis using gas chromatography coupled with mass spectrometric detection, which identified a total of 71 compounds across different plant parts, including the root (underground part), root (aerial part), leaf, stem, and flowering aerial part. The predominant biologically active compound identified across all plant parts was Ethyl α-D-glucopyranoside. Monoterpenes, recognized as primary secondary metabolites, were notably abundant in each plant part, with varying compositions: the root (underground part) contained 28.58% aliphatic monoterpenes, 54.41% oxygenated monoterpenoids, 1.42% diterpenoids, and 15.59% other compounds; the root (aerial part) exhibited 1.34% aliphatic monoterpenes, 31.28% oxygenated monoterpenoids, 6.16% diterpenoids, and 61.22% other compounds; the stem and leaves showed 3.06% aliphatic monoterpenes, 21.49% oxygenated monoterpenoids, 17.99% diterpenoids, and 57.46% other compounds; and the flowering aerial part displayed 8.20% aliphatic monoterpenes, 53.18% oxygenated monoterpenoids, 23.75% diterpenoids, and 14.87% other compounds. Diterpenes, particularly Phytol, were prominently present in the leaf, stem, and flowering aerial parts. Additionally, a diverse array of organic acids, ketones, and phenolic compounds were identified across the plant parts, each potentially offering distinct pharmacological benefits. The presence of exclusive compounds in specific plant parts, such as Dihydroxyacetone in the root (aerial part), underscored the pharmacological diversity of S. ewersii. This study provides valuable insights into the chemical diversity and pharmacological potential of S. ewersii, suggesting promising applications in pharmaceutical and medicinal fields. Further research aimed at elucidating the individual and synergistic pharmacological effects of these compounds is crucial to fully harness the therapeutic benefits of this plant. Full article

Dihydroxyacetone phosphate (DHAP)-dependent aldolases catalyze the aldol addition of DHAP to a variety of aldehydes and generate compounds with two stereocenters. This reaction is useful to synthesize chiral acyclic nucleosides, which constitute a well-known class of antiviral drugs currently used. In such compounds, the chirality of the aliphatic chain, which mimics the open pentose residue, is crucial for activity. In this work, three DHAP-dependent aldolases: fructose-1,6-biphosphate aldolase from rabbit muscle, rhanmulose-1-phosphate aldolase from Thermotoga maritima, and fuculose-1-phosphate aldolase from Escherichia coli, were used as biocatalysts. Aldehyde derivatives of thymine and cytosine were used as acceptor substrates, generating new acyclic nucleoside analogues containing two new stereocenters with conversion yields between 70% and 90%. Moreover, structural analyses by molecular docking were carried out to gain insights into the diasteromeric excess observed. Full article

The strain Gluconobacter oxydans LMG 1385 was used for the bioconversion of crude glycerol to dihydroxyacetone. The suitability of fed-batch cultures for the production of dihydroxyacetone was determined, and the influence of the pH of the culture medium and the initial concentration of glycerol on maximizing the concentration of dihydroxyacetone and on the yield and speed of obtaining dihydroxyacetone by bioconversion was examined. The feeding strategy of the substrate (crude glycerol) during the process was based on measuring the dissolved oxygen tension of the culture medium. The highest concentration of dihydroxyacetone P_K = 175.8 g·L⁻¹ and the highest yield Y_P/Sw = 94.3% were obtained when the initial concentration of crude glycerol was S₀ = 70.0 g·L⁻¹ and the pH of the substrate was maintained during the process at level 5.0. Full article

KDO (2-keto-3-deoxy-D-manno-octulosonate) is a landmark molecule of the Gram-negative outer membrane. Mutants without KDO formation are known to be barely viable. Arabinose 5-phosphate (A5P) is a precursor of KDO biosynthesis and is normally derived from ribulose 5-phosphate by A5P isomerases, encoded by kdsD and gutQ genes in E. coli K-12. We created a kdsD gutQ-deficient double mutant of strain BW25113 and confirmed that these cells are A5P auxotrophs. Fructose 6-phosphate aldolase (FSA) is known to utilize (among other donors such as dihydroxyacetone or hydroxyacetone) glycolaldehyde (GoA) as a donor compound and to provide A5P in vitro when glyceraldehyde 3-phosphate is the acceptor. We show here that this FSA function in vivo fully reverses the growth defect and the A5P deficiency in kdsD gutQ double mutants. Expression of both plasmid-encoded fsaA, fsaA^A129S, or fsaB genes as well as a chromosomally integrated form of fsaA^A129S led to maximal OD₆₀₀ values of >2.2 when GoA was added exogenously (together with glucose as a C source) at a concentration of 100 µM (K_s values in the range of 4–10 µM). Thus, a novel bio-orthogonal bypass to overcome an A5P deficiency was opened. Lower GoA concentrations led to lower growth yields. Interestingly, mutant strains with recombinant fsa genes showed considerable growth yields even without exogenous GoA addition, pointing to yet unknown endogenous GoA sources in E. coli metabolism. This is a further example of the usefulness of FSA in rewiring central metabolic pathways in E. coli. Full article

Three types of CuO with different micro–structures were applied to catalyze the conversion of glycerol to lactic acid. The structure–activity relationship between CuO and its catalytic performance was investigated by combining experiments and theoretical calculations. We demonstrated that two CuO samples (CuO–BCC and CuO–CA), as prepared by calcining copper salts, show larger lattice spacing than that of commercial CuO (CuO–COM). In the catalytic experiments, CuO–BCC, which had the largest lattice spacing (d = 0.2480 nm), exhibited the highest yield of 78.54% for lactic acid. The lattice strain caused by lattice expansion was considered more favorable for CuO–BCC in adsorbing glycerol molecules, thereby improving the conversion of glycerol to lactic acid. The DFT simulation calculation results further prove that CuO–BCC has a larger adsorption energy for glycerol and a smaller thermodynamic energy barrier for the dehydrogenation of glycerol to form the key intermediate products (glyceraldehyde and 1,3-dihydroxyacetone) than CuO–COM. This study demonstrates the role of lattice strain effects in the development of catalysts and provides ideas for catalytic glycerol-selective oxidation studies. Full article

Osteoarthritis (OA) is a common cause of lameness in sport horses with a significant economic impact. The prevention of OA is crucial since no effective treatment is available. This study aimed to apply untargeted metabolomic analysis to investigate the differences in synovial fluid (SF) composition between healthy and OA-affected joints in horses. SF collected from healthy (n.8) and OA (n.11) horses was analyzed using H-NMR analysis. Metabolomic analysis allowed 55 different metabolites to be identified and quantified in SF samples. Nineteen metabolites were found to be differently concentrated in OA compared to control horses. Synovial fluids from the OC group were found to be higher in 1,3-dihydroxyacetone but lower in tryptophan, phenylalanine, tyrosine, uridine, creatinine, creatine, glycine, choline, asparagine, glutamine, arginine, 3-hydroxybutyrate, valine, 2-hydroxyisovalerate, α-ketoisovaleric acid, 3-methyl-2-oxovalerate, 3-hydroxyisobutyrate, isoleucine, and methionine compared to the controls. A variety of SF metabolites significantly changed following joint disease, demonstrating the complex mechanism underlying osteoarthritis in horses and highlighting the value of applying the metabolomic approach in clinical research. Full article