Glyoxylate Research Articles

Delayed Graft Function After Kidney Transplantation: The Role of Residual Diuresis and Waste Products, as Oxalic Acid and Its Precursors.

Delayed graft function (DGF) after kidney transplantation heralds a worse prognosis. In patients with hyperoxaluria, the incidence of DGF is high. Oxalic acid is a waste product that accumulates when kidney function decreases. We hypothesize that residual diuresis and accumulated waste products influence the DGF incidence. Patients transplanted between 2018-2022 participated in the prospective cohort study. Pre-transplant concentrations of oxalic acid and its precursors were determined. Data on residual diuresis and other recipient, donor or transplant related variables were collected. 496 patients were included, 154 were not on dialysis. Oxalic acid, and glyoxylic acid, were above upper normal concentrations in 98.8%, and 100% of patients. Residual diuresis was ≤150mL/min in 24% of patients. DGF occurred in 157 patients. Multivariable binary logistic regression analysis demonstrated a significant influence of dialysis type, recipient BMI, donor type, age, and serum creatinine on the DGF risk. Residual diuresis and glycolic acid concentration were inversely proportionally related to this risk, glyoxylic acid directly proportionally. Results in the dialysis population showed the same results, but glyoxylic acid lacked significance. In conclusion, low residual diuresis is associated with increased DGF incidence. Possibly accumulated waste products also play a role. Pre-emptive transplantation may decrease the incidence of DGF.

CCR2 antagonist attenuates calcium oxalate-induced kidney oxidative stress and inflammation by regulating macrophage activation.

C-C chemokine receptor type 2 (CCR2) is a monocyte chemokine associated with oxidative stress and inflammation. Kidney stones (KS) are composed of calcium oxalate (CaOx), which trigger renal oxidative stress and inflammatory. This study aims to evaluate the effects of CCR2 on KS in vivo and in vitro. Eight-week-old male C57BL/6J mice were intraperitoneally injected with glyoxylate (GOX) daily to establish a KS model, and along with CCR2 antagonist (INCB3344) treatment on days 2, 4, and 6. The results showed that CCR2 antagonist reduced renal injury markers (blood urea nitrogen and serum creatinine), alleviated renal tubular injury and CaOx crystal deposition. CCR2 antagonist also decreased CCR2 expression induced by GOX treatment and increased Nrf2 expression. GOX treatment promoted malondialdehyde (MDA) production, decreased glutathione (GSH) content, and inhibited catalase (CAT) and superoxide dismutase (SOD) activity, however, CCR2 antagonist attenuated the above effects of GOX. CCR2 antagonist had inhibitory effects on GOX-induced inflammatory cytokine expression (IL1B, IL6 and MCP1), and inhibited apoptosis by increasing Bcl-2 expression and decreasing Bax and cleaved-caspase 3 expression. In vitro experiments were performed by co-culture model of CaOx-induced damaged HK-2 cells and macrophage-like THP-1 cells. CCR2 antagonist inhibited CaOx-induced THP-1 cell M1 polarization by decreasing the TNF-α, IL6 and iNOS levels, and further alleviated CaOx-induced oxidative stress damage, inflammatory response and apoptosis of HK-2 cells. The study suggests that CCR2 antagonist may be resistant to CaOx crystals-induced oxidative stress and inflammation by inhibiting macrophage M1 polarization.

Metabolomics studies in common multifactorial eye disorders: a review of biomarker discovery for age-related macular degeneration, glaucoma, diabetic retinopathy and myopia.

Multifactorial Eye disorders are a significant public health concern and have a huge impact on quality of life. The pathophysiological mechanisms underlying these eye disorders were not completely understood since functional and low-throughput biological tests were used. By identifying biomarkers linked to eye disorders, metabolomics enables early identification, tracking of the course of the disease, and personalized treatment. The electronic databases of PubMed, Scopus, PsycINFO, and Web of Science were searched for research related to Age-Related macular degeneration (AMD), glaucoma, myopia, and diabetic retinopathy (DR). The search was conducted in August 2023. The number of cases and controls, the study's design, the analytical methods used, and the results of the metabolomics analysis were all extracted. Using the QUADOMICS tool, the quality of the studies included was evaluated, and metabolic pathways were examined for distinct metabolic profiles. We used MetaboAnalyst 5.0 to undertake pathway analysis of differential metabolites. Metabolomics studies included in this review consisted of 36 human studies (5 Age-related macular degeneration, 10 Glaucoma, 13 Diabetic retinopathy, and 8 Myopia). The most networked metabolites in AMD include glycine and adenosine monophosphate, while methionine, lysine, alanine, glyoxylic acid, and cysteine were identified in glaucoma. Furthermore, in myopia, glycerol, glutamic acid, pyruvic acid, glycine, cysteine, and oxoglutaric acid constituted significant metabolites, while glycerol, glutamic acid, lysine, citric acid, alanine, and serotonin are highly networked metabolites in cases of diabetic retinopathy. The common top metabolic pathways significantly enriched and associated with AMD, glaucoma, DR, and myopia were arginine and proline metabolism, methionine metabolism, glycine and serine metabolism, urea cycle metabolism, and purine metabolism. This review recapitulates potential metabolic biomarkers, networks and pathways in AMD, glaucoma, DR, and myopia, providing new clues to elucidate disease mechanisms and therapeutic targets. The emergence of advanced metabolomics techniques has significantly enhanced the capability of metabolic profiling and provides novel perspectives on the metabolism and underlying pathogenesis of these multifactorial eye conditions. The advancement of metabolomics is anticipated to foster a deeper comprehension of disease etiology, facilitate the identification of novel therapeutic targets, and usher in an era of personalized medicine in eye research.

Functional deep eutectic solvent for lignocellulose valorization via lignin stabilization and cellulose functionalization

The pretreatment of lignocellulosic biomass with a functional DES that incorporates choline chloride (ChCl) and glyoxylic acid (GA) resulted in a high removal of lignin and hemicellulose, lignin stabilization, and cellulose functionalization.

Unravelling the prebiotic origins of the simplest α-ketoacids in cometary ices: a computational investigation.

We have employed the ab initio nanoreactor (AINR) and DFT calculations to explore how the soft impact of comets entering early earth's dense atmosphere could induce chemical reactions in trapped interstellar ice components, leading to the origin of glyoxylic and pyruvic acids the simplest α-ketoacids essential for prebiotic metabolic cycles.

Fulvic acid modification with phenolic precursors towards controllable solubility performance

The solubility of fulvic acid was tuned through acid-catalyzed condensation with phloroglucinol and glyoxylic acid to enable prolonged delivery of its beneficial properties, such as complexation, buffering, transport of vitamins and minerals, to soil.

Evaluating the native oxide of titanium as an electrocatalyst for oxalic acid reduction.

Herein, we show that unmodified titanium electrodes bearing the naturally-forming native TixOy coating display superior activity for the electroreduction of oxalic acid to glyoxylic acid and glycolic acid compared to Ti-based electrodes that have been deliberately modified for this purpose, in terms of both oxalic acid conversion and overall yields of reduced products.

Coronenes with push-pull geometries from macrocycle-forming Perkin condensations.

Although the Perkin reaction has been successful in producing ester-substituted conjugated macrocycles with four or six building blocks, macrocycles composed of only two elements remained elusive until now. Through the development of a building block derived from phenanthrene with two glyoxylic acid substituents in a pincer-like arrangement, formation of a two-block macrocycle was induced when paired with a complementary phenylenediacetic acid unit. The addition of ether functions to the phenanthrene building block not only improved the yields, but led to macrocycles with push-pull geometries. Photocyclisation of the resulting cyclophanes efficiently yield tetra- and hexasubstituted coronenes.

Deoxyfluorination with superacids - synthesis and characterization of protonated α-fluorohydroxyacetic acid.

α-Fluoroalcohols describe a rare and unstable class of compounds, accessible mainly by fluorination of highly electrophilic carbonyl compounds. In this work, we report the syntheses of α-fluorohydroxyacetic acid (FHA) and its acyl fluoride (FHA-F) by reacting the dihydroxy species glyoxylic acid monohydrate (GAM) with SF4. Surprisingly, only one of the geminal hydroxy groups is substituted when excess SF4 is employed. Implementing GAM with the binary superacid HF/AsF5 also leads to a single yet quantitative deoxyfluorination at the diol group. The reaction pathways are discussed based on NMR experiments, the characterization was carried out using NMR and vibrational spectroscopy as well as single-crystal X-ray diffraction.

Organic pollutants degradation by glyoxylic acid boosted Fenton-like system: An overlooked Fe(III)/Fe(II) cycles with low-molecular-weight organic acid

Herein, glyoxylic acid (GA) was incorporated into the Fenton-like (Fe(III)/H2O2) system to rigorously examine its impact on the degradation of organic pollutants. It was found that the degradation efficiencies of atrazine (ATR), ofloxacin (OFL), rhodamine B (RhB), and carbamazepine (CBZ) in the Fe(III)/GA/H2O2 system were ∼95%, and the apparent ATR degradation rate constant (1.60 × 10−2 min−1) was 4-fold as high as that (0.40 × 10−2 min−1) in the Fe(III)/H2O2 system at pH 3.6. The UV–vis spectral and cyclic voltammetry (CV) analyses demonstrated that GA could be used as a ligand and reductant to coordinate and reduce Fe(III), thereby promoting the Fe(III)/Fe(II) cycles in the Fenton-like process. Testing results for reactive oxygen species (ROS) confirmed that superoxide ions (•O2–) and hydroxyl radicals (•OH) respectively undertake the Fe(III)/Fe(II) cycles and ATR degradation in the Fe(III)/GA/H2O2 system. The reaction stoichiometric efficiencies (RSE) in the Fe(III)/GA/H2O2 system (37.5%–76.9%) were significantly higher than those (2.8%–4.9%) in the Fe(III)/H2O2 system within 180 min, and the maximum concentration of •OH in the Fe(III)/GA/H2O2 system was 4.6 times that in the Fe(III)/H2O2 system. A series of the important variables were optimized in detail, including solution pH, GA dosage, amount of Fe(III) and H2O2. These findings provide compelling evidence for the non-negligible role of GA in the processes of organic pollutants degradation based on the Fe(III)/Fe(II) cycles and radicals generation in the Fenton-like system.

The Synthesis of Some Imine Derivatives via Condensation Reactions between Some Aromatic Phenylhydroxylamine Derivatives with Glyoxylic Acid and the Study of their biological activity

This study investigated the condensation reactions between N-(3,4-dimethoxybenzyl)hydroxylamine and N-(4-methylbenzyl)hydroxylamine with glyoxalic acid. The objective was to obtain imine derivatives as the desired target products. FT-IR, 1H-NMR, and 13C-NMR spectroscopic techniques were used to identify the structures of the produced compounds. Different conditions were considered for these reactions and only N-(3,4-dimethoxybenzyl)hydroxylamine could be converted to the desired nitrone. Finally, the antimicrobial efficacy was assessed in terms of its action against the bacteria Escherichia coli (E.coli) as Gram-negative bacteria, Staphylococcus aureus (S.aureus) as Gram-positive bacteria and fungus (Candida albicans). The activity data proved that this nitrone showed significant antimicrobial activity compared to standard drugs.

Nanostructure-performance relationships in titania-only electrodes for the selective electrocatalytic hydrogenation of oxalic acid

The preparation of robust and selective hydrogenation electrodes not based on critical raw materials is a relevant goal for the development of sustainable electrocatalytic processes. Oxalic acid is an emerging intermediate produced from CO2 that can be used to produce valuable, added-value monomers for high-performance polymers by selective electrocatalytic reduction. We demonstrated that with the rapid breakdown anodization (RBA) method, superior-performance TiO2-only electrodes can be directly prepared with a fast and low-cost procedure. The electrodes were based on a conductive Ti substrate, used to generate a roughened titania layer by RBA characterized by an ordered array of vertically aligned TiO2 nanotubes (NTs) on top of them and partially reduced TiO2-x nanoparticles stabilized by the interaction with the NTs layer. In addition, the preparation method leads to highly nanoporous NTs. The electrodes obtained by RBA at 60 V led to the best Faradaic efficiency (FE) to glycolic acid (86 %) and oxalic conversion (48 %) at −0.8 V vs. RHE, superior to the existing literature on TiO2-only electrodes at room temperature. The NTs structural features, such as length and surface roughness, were calculated by AFM and linearly correlated with the oxalic acid conversion and the electrochemical active surface area (ECSA). Additionally, the ECSA was found to be correlated with selectivity, indicating the complex interrelations between the NT nanostructure and performance. This finding emphasizes the importance of controlling the nanostructure as a critical factor in tuning the selectivity toward glyoxylic acid or glycolic acid.

PROSPECTS FOR MODIFYING THE STRUCTURE OF CHITIN AND CHITOSAN OF HIGHER FUNGI TO EXPAND THE POTENTIAL OF THEIR APPLIED USE

The review is devoted to summarizing scientific data in the field of the chemical structure and properties of chitin and chitosan obtained from fungal biomass, and to analyzing directions for their modification for use in medicine and the food industry as substances with antibacterial, antiviral, wound-healing and anticoagulant activity. The features of chitin biosynthesis by fungi of the Basidiomycota, Ascomycota, Deuteromycota departments and chitosan biosynthesis by fungi of the Zygomycota department are covered. It has been shown that higher fungi contain chitin in their cell walls in the form of a chitin-glucan complex, while lower fungi (zygomycetes) contain chitin in the form of chitosan-glucan. Effective components of substrates that influence the production of polysaccharides by fungi have been identified - carbohydrates in the form of glucose, sucrose and maltose, organic forms of nitrogen in the form of yeast extract and corn flour, mineral components in the form of dihydrogen phosphate and dipotassium monohydrogen phosphate. Particular attention is paid to methods for isolating chitin and modifying it to chitosan with a detailed description of the physicochemical and biological properties of polymers. The review also presents the main reactions and methods for obtaining carboxymethyl and sulfo derivatives of chitin and chitosan. The biological properties and application of these groups of substances are described. In the carboxymethylation of chitin and chitosan, the choice of appropriate reaction conditions and reagents makes it possible to obtain carboxymethyl chitin, N-, O-, N,O-carboxymethylchitosan, or N,N-dicarboxymethylchitosan. The properties and applications of carboxymethyl derivatives of chitin and chitosan strongly depend on their structure, degree of substitution, and arrangement of amino or hydroxyl groups. The main reagents in the preparation of carboxymethyl derivatives are sodium monochloroacetate, monochloroacetic and glyoxalic acids. Carboxymethyl derivatives of chitin and chitosan are used as drug delivery systems, antimicrobial agents, in tissue engineering, as components of cosmetics and food products. Modification of chitosan with sulfate groups makes it possible to obtain chitosan 2-N-, 6-O-, 2-N-6-O- and 3-O-sulphates. The main sulfonating agents are oleum, pyridine and chlorosulfonic acid. Sulfonic derivatives of chitin and chitosan can be used as a basis for obtaining hemocompatible materials (with antithrombotic and antibacterial activities).

Theoretical insight into the aqueous transformation mechanism of terbutaline using O3 and •OH of advanced oxidation processes

Terbutaline (TBL, an β-agonists pharmaceuticals) is one of the pharmaceuticals and personal care products (PPCPs), which has caused many environmental concerns due to its eco-toxicological effects in aquatic environment. In this research, density functional theory (DFT) and quantitative structure–activity relationships (QSARs) toxicity methods were performed to systematically elucidate the transformation mechanisms and ecological risk of TBL degraded by •OH and O3. By analyzing the structure and electronic properties of TBL, the •OH-addition, H-abstraction, single electron transfer and 1, 3-cycloaddition ozonation degradation pathways were mainly investigated. The lowest energy barriers of •OH and O3 initiated reactions in the degradation process were 7.33 and 18.49 kcal mol−1 respectively, which indicated that the •OH degradation process was more likely to occur than O3 induced reactions from a thermodynamic perspective. The kinetic rate constants of O3 and •OH at 298 K were calculated as 7.58 M−1 s−1 and 1.02 × 109 M−1 s−1, respectively. Furthermore, the subsequent intermediates could further transform into hydroxylation substitutes, glyoxylic acid and ketoaldehyde by-products. Based on toxicity assessments, parent reactant TBL can exhibit harmful acute and chronic toxicity to daphnid (identified by LC50 33.2 mg L−1 and ChV 2.34 mg L−1). The toxicity of most of the degradation products was reduced to harmless level compared with the parent reactant TBL. This work provided a molecular level understanding for evaluating the contribution of O3 and •OH to the removal of TBL from wastewater by theoretical calculations.

Glycated bovine serum albumin for use in feeding trials with animal models - In vitro methodology and characterization of a glycated substrate for modifying feed pellets.

This study investigated different methods to produce Nε-carboxymethyl-lysine (CML)-enriched bovine serum albumin (BSA) as alternatives to the classical approach using glyoxylic acid (GA) and sodium cyanoborohydride (NaBH3CN) which results in toxic hydrogen cyanide (HCN). The reaction of GA (6mmol/L) and NaBH3CN (21mmol/L) to produce CML remained the most effective with CML yields of 24-35%, followed by 13-24% using 300mmol/L glyoxal (GO). GA promoted specific modification of lysine to CML, and fewer structural modifications of the BSA molecule compared with GO, as evidenced by fluorescence and proteomic analyses. GO promoted greater arginine modification compared with GA (76 vs 23%). Despite structural changes to BSA with GO, murine fecal clearance of CML was similar to literature values. Hence, BSA glycation with 300mmol/L glyoxal is a suitable alternative to GA and NaBH3CN for generating CML-enriched protein free of HCN, but a CML-only fortification model remains to be described.

Microwave measurements and structure calculations for a glyoxylic acid – Water complex

The microwave spectra for a hydrogen-bonded trans-2 glyoxylic acid–water complex were measured in the 6–16 GHz frequency range using two Flygare-Balle type pulsed beam Fourier transform microwave (FTMW) spectrometers. The rotational constants for the dimer were determined to have the following values: A = 9384.2354(31), B = 1707.63973(73), and C = 1447.44879(56) MHz. The hydrogen bonded structures and rotational constants were calculated for the lowest energy dimglyoxylic acid - water using DFT, MP2 and CCSD calculations with various basis sets. The B3LYP/aug-cc-PVQZ-DG3 calculations yielded rotational constants of A = 9393.59, B = 1713.76, and C = 1453.23 MHz, in very good agreement with experimental values. The calculations show two feasible tunneling motions involving hydrogen atoms in this complex.

Regulation and mechanism of pyrite and humic acid on the toxicity of arsenate in lettuce

Pyrite and humic acid are common substances in nature, and the combined effects of pyrite and humic acid on arsenic phytotoxicity are more widespread in the actual environments than that of a single substance, but have received less attention. In this study, the interaction between pyrite and humic acid in arsenate solution was studied, and the effects of pyrite and humic acid on plant toxicity of arsenate were evaluated. The results showed that arsenate + pyrite + fulvic acid (V-PF) treatment immobilized more arsenic by forming chemical bonds such as AsS and Fe-As-O and reduced the migration of arsenic to plants. Compared to the arsenate + fulvic acid (VF), arsenate + pyrite (VP) and arsenate (V) group, the inorganic arsenic content of lettuce leaves in the V- PF group was reduced by 19.8 %, 13.4 % and 13.4 %, respectively. In addition, the V-PF group increased the absorption of Ca, Fe and Cu in plant roots, and improved the activity of superoxide dismutase (SOD) in plant leaves. Compared to the VF group, SOD and MDA in the V-PF group increased by 34.1 % in 30 days and decreased by 47.3 % in 40 days, respectively. The biomass of lettuce in V-PF group was increased by 29.3 % compared with that in VF group on day 50. The protein content of the V-PF group was 58.3 % higher than that of the VF group and 23.1 % higher than that of the VP group. Furthermore, metabolomics analysis showed that the V-PF group promoted glycolysis by up-regulating glyoxylic acid and dicarboxylic acid metabolism, thus reducing carbohydrate accumulation. Phosphocreatine metabolism was also up-regulated, which decreased the oxidative damage in lettuce induced by arsenic. This study will provide new ideas for scientifically and rationally assessing the ecological environmental risks of arsenic and regulating its toxicity.

Direct photodegradation of internally mixed sodium chloride and malonic acid single aerosols: Impact of the photoproducts on the hygroscopic properties of the particles

Sea-salt aerosols (SSA) are one of the key natural aerosols in our atmosphere, consisting predominantly of sodium chloride (NaCl). Throughout their atmospheric transport, these aerosols undergo complex internal mixing, giving rise to a rich variety of inorganic and organic species, including dicarboxylic acids. This study investigates firstly the composition and deliquescence properties of coarse particles containing pure malonic acid (MA2, CH2(COOH)2) and internally mixed NaCl and MA2, by means of an acoustic levitation system coupled with a Raman microspectrometer. Secondly, we report here the first experimental observation and characterization of the products arising from photochemical reactions under UV–Visible irradiation (338 ≤ λ ≤ 414 nm) in the absence of an oxidant under acoustic levitation conditions in MA2 and NaCl/MA2 aerosols. Furthermore, the impact of photodegradation on the hygroscopic properties of these particles is examined. We confirmed the irreversible formation of monosodium malonate (NaMA, HOOCCH2COONa), which coexists with NaCl or MA2 on non-irradiated particles. We also demonstrated the formation of oxalic acid (OA2, HOOC–COOH) within irradiated MA2 droplets and the appearance of glyoxylic acid (GlyA, HCOCOOH) in NaCl containing droplets. The photolysis process exerts a marked effect on the hygroscopic properties of the particles, resulting in a shift in deliquescence transitions toward higher relative humidity (RH) values. This study contributes to the understanding of the intricate physicochemical processes involved in SSA during their atmospheric transport. Likewise, this work sheds light on the impacts of these types of aerosols on cloud formation and climate change.

Ductile, High-Lignin-Content Thermoset Films and Coatings.

In the context of transitioning toward a more sustainable use of natural resources, the application of lignin to substitute commonly utilized petroleum-based plastics can play a key role. Although lignin is highly available at low cost and presents interesting properties, such as antioxidant and UV barrier activities, its application is limited by its low reactivity, which is a consequence of harsh conditions normally used to extract lignin from biomass. In this work, the use of glyoxylic acid lignin (GA lignin), rich in carboxylic acid groups and hence highly reactive toward epoxy cross-linkers, is presented. GA lignin, which is directly extracted from biomass via a one-step aldehyde-assisted fractionation process, allowed the preparation of thermoset films and coatings via a simple reaction with sustainable poly(ethylene glycol) diglycidyl ether and glycerol diglycidyl ether cross-linkers. This allows one to prepare freestanding films containing up to 70 wt % lignin with tunable mechanical properties and covalently surface-attached coatings containing up to 90 wt % lignin with high solvent resistance. Both films and coatings display antioxidant properties and combine excellent UV barrier activity with high visible transparency, which is attractive for applications in sustainable food packaging.

Glyoxylic Acid Monohydrate-Promoted Formation of the C-SO2 Bond Starting from Maleimides/Quinones and Sodium Sulfinates.

By using glyoxylic acid monohydrate as a promoter, a wide range of substances containing a C-SO2 bond could be obtained from N-substituted maleimides or quinones and sodium sulfinates. The protocol features mild reaction conditions, short reaction time, and good atomic economics, which provides an alternative protocol for the α-sulfonylation of α,β-unsaturated ketones.