Search Results (655)

The accumulation dynamics and regulatory mechanisms of the alkylamides, the key pungent compounds in the fruits of Sichuan peppers, remain poorly understood. Using fruits of the Zanthoxylum planispinum var. dintanensis (Dintan) harvested at five key developmental stages, we comprehensively mapped the accumulation of numbering compounds and their underlying molecular drivers by integrating HPLC-based metabolite profiling and de novo transcriptomics. Total alkylamide content increased during development, with hydroxyl-α-sanshool (HαSS) being predominant. The contributions of hydroxyl-β-sanshool (HβSS) and hydroxyl-ε-sanshool (HεSS) increased in later stages. Cluster and correlation analyses identified 51 candidate genes strongly correlated (|r| ≥ 0.6) with HαSS accumulation, predominantly enriched in fatty acid and branched-chain amino acid metabolism pathways. The expression patterns of five stearoyl-CoA desaturase (SCD) genes, one long-chain acyl-CoA synthetase (ACSL/fadD), and one S-(hydroxymethyl)glutathione dehydrogenase/alcohol dehydrogenase (frmA) gene closely mirrored HαSS accumulation. In contrast, 3-oxoacyl-[acyl-carrier-protein] synthase II (fabF) and one β-ketoacyl-CoA synthase (KCS) gene exhibited a negative correlation. Accordingly, a positive regulatory network was constructed for HαSS accumulation. These findings revealed key candidate targets for deciphering the molecular basis of its unique flavor and for breeding high-pungency cultivars. Full article

There is accumulating evidence that distinct mitochondrial DNA (mtDNA) methylation and hydroxymethylation patterns exist in Parkinson’s disease (PD). However, most studies have been limited to the investigation of specific target regions, rather than the entire mtDNA, and have been further hindered by other methodological discrepancies and the lack of non-CpG context investigation. Here, we provide a comprehensive profile of methylation and hydroxymethylation levels across the mitochondrial genome, at global and single-base resolution, in CpG and non-CpG (CHG, CHH) contexts in blood samples from early-onset PD (EOPD) patients (n = 39) and age- and sex-matched controls (n = 63). Bisulfite (BS) and oxidative-bisulfite (oxBS) conversions in parallel workflows followed by next-generation sequencing (NGS) using Illumina’s Novaseq 6000 sequencing system identified mitochondrial 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) in all contexts. Global mtDNA methylation was significantly higher in EOPD patients vs. matched controls in the CpG context (p = 5.63 × 10⁻³) in the BS status, and in all contexts [CpG (p = 2.67 × 10⁻⁴), CHG (p = 0.015), CHH (p = 0.012)] in the oxBS status, i.e., “true methylation”. At single-base resolution, the most statistically significant sites across the mitogenome, in the D-loop region, and CpG context, were primarily hypomethylated in EOPD patients compared to matched controls. Upon further validation, both global and base resolution mtDNA (hydroxy)methylation results could act as blood-based biomarkers for EOPD. Full article

G-quadruplex (G4) DNA structures have recently emerged as promising chiral scaffolds for enantioselective catalysis. This study investigates how thymidine loop modifications influence the catalytic performance of the telomeric G4 sequence HT21 in the asymmetric sulfoxidation of thioanisole. To this end, several singly or doubly modified HT21 derivatives were synthesized by using β-L-2′-deoxythymidine, 5-hydroxymethyl-2′-deoxyuridine, and 5-bromo-2′-deoxyuridine instead of a T residue, or β-L-2′-deoxyadonesine instead of an A residue, in specific positions within the TTA loops. The catalytic activity of these analogues was evaluated in the Cu(II)-mediated oxidation of thioanisole using hydrogen peroxide as oxidant. All modified sequences maintained complete substrate conversion, but their enantioselectivities varied markedly. Whereas the highest enantiomeric excess (84% ee) had previously been achieved with the HT21 analogue bearing a β-L-2′-deoxyadenosine in the first loop, the thymidine-based modifications, either alone or in combination, resulted in lower ee values, suggesting that loop alterations critically affect the chiral microenvironment, not all loop positions are functionally equivalent, and single substitutions within the same loop can result in different enantioselectivities. These findings highlight new insights on how individual loop residues contribute to asymmetric induction and offer further details for tuning G4-based catalytic scaffolds. Full article

Green chemistry, achieved by using water as a reaction medium, has several potential applications. In this work, a number of water-soluble Rh(III)–THP complexes, [Rh(III)Cl₃(OH)(THP)₂]⁻ (1), [Rh(III)Cl₂(OH)(THP)₃] (2), [Rh(III)Cl(OH)(THP)₄]⁺ (3), [Rh(III)Cl(OH)(en)(THP)₂]⁺ (4a), [Rh(I)(en)(THP)₂]⁺ (4b) and [Rh(III)(en)₂Cl₂]Cl (5) (where THP = P(CH₂OH)₃), were generated in aqueous media by controlling the reaction at different molar ratios of RhCl₃/THP/en (en: ethylenediamine). These complexes were fully characterized in situ by ³¹P NMR spectroscopy, base titration and by X-ray crystallography for the solid compound (4). The catalytic hydrogenation reactivities of freshly prepared complexes (1–5) were tested in situ with the selected substrate of 3,4-dimethoxystyrene under the same experimental conditions; the related catalytic reactivities are discussed in detail. Full article

Electrocatalytic hydrogenation (ECH) represents an environmentally friendly pathway for converting 5-hydroxymethylfurfural (HMF) into the high-value chemical 2,5-bis(hydroxymethyl)furan (BHMF). However, its selectivity and Faradaic efficiency are often constrained by competitive hydrogen evolution at the cathode and insufficient supply of active hydrogen at the surface. To address this challenge, this study developed an Ir-decorated copper oxide nanowire catalyst (denoted as CuIr) featuring a hydrogen-rich adsorption (H_ads) surface. The incorporation of Ir significantly enhances the catalyst’s water dissociation capacity, creating abundant H_ads sources that selectively accelerate HMF hydrogenation while suppressing side reactions. Under a mild applied potential of −0.45 V vs. RHE and a current density of approximately −20 mA cm⁻², the optimal CuIr₄₀ catalyst achieved near-complete conversion of HMF (99%), a BHMF yield of 99%, and a high Faradaic efficiency of 97% within 120 min of electrolysis. Mechanistic studies reveal that this catalytic leap stems from the synergistic functional interaction between Cu and Ir sites in substrate activation and hydrogen supply. This work presents a novel strategy for designing efficient electrocatalysts for biomass hydrogenation by regulating surface H_ads concentration. Full article

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and fibromyalgia (FM) are debilitating disorders with overlapping symptoms such as chronic pain and fatigue. Dysregulation of the endogenous opioid system, particularly µ-opioid receptor function, may contribute to their pathophysiology. This study examined whether epigenetic modifications, specifically µ-opioid receptor 1 gene (OPRM1) promoter methylation, play a role in this dysfunction. Using a repeated-measures design, 28 ME/CFS/FM patients and 26 matched healthy controls visited the hospital twice within four days. Assessments included blood sampling for epigenetic analysis, a clinical questionnaire battery, and quantitative sensory testing (QST). Global DNA (hydroxy)methylation was quantified via liquid chromatography–tandem mass spectrometry, and targeted pyrosequencing was performed on promoter regions of OPRM1, COMT, and BDNF. ME/CFS/FM patients reported significantly worse symptom outcomes. No differences in global (hydroxy)methylation were found. Patients showed significantly higher OPRM1 promoter methylation, which remained after adjusting for symptom severity and QST findings. Across timepoints, OPRM1 methylation consistently correlated with BDNF Promoter I and Exon III methylation. This is, to the best of our knowledge, the first study examining OPRM1 methylation in ME/CFS/FM. Increased OPRM1 methylation in patients, independent of symptoms or pain sensitivity measures, supports the hypothesis of dysregulated opioidergic signaling in these conditions. Full article

A facile and single-step synthesis of poly(L-Cysteine) (p(L-Cys)) particles through microemulsion polymerization using tetrakis(hydroxymethyl) phosphonium chloride (THPC) as crosslinker is accomplished for the first time. The L-Cys:THPC ratio in p(L-Cys) particles was calculated as 80:20% (by weight) with elemental analyses, and the generation of p(L-Cys) particles was confirmed. SEM imaging revealed a popcorn-like morphology of the p(L-Cys) particles with a 1–20 µm particle size range. The isoelectric point of p(L-Cys) particles was determined at pH 1.15 via zeta potential measurements. The hydrolytic degradation of p(L-Cys) particles was determined as about 85% within 3 h (by weight). The p(L-Cys) particles displayed excellent blood compatibility with a hemolysis % ratio of <2.3% and a blood clotting index of 95% at 1 mg/mL concentration. Moreover, cell compatibility tests up to 50 mg/mL against L929 fibroblast cells exhibited about 90% cell viability for p(L-Cys) particles versus 58% for L-Cys molecule. The antimicrobial efficacy of the L-Cys molecules was notably enhanced in p(L-Cys) particles, exhibiting a 5-fold reduction in minimal bactericidal concentration (MBC) values against E. coli (Gram-negative, ATCC 8739) and a 2-fold reduction against S. aureus (Gram-positive, ATCC 6538). Additionally, the antioxidant capacity of p(L-Cys) particles was retained somewhat, measured as 0.14 ± 0.01 µM versus 2.25 ± 0.03 µM Trolox equivalent/g for L-Cys. Therefore, p(L-Cys) particles are versatile and offer a unique avenue for immense biomedical use. Full article

Curcuminoids demonstrate diverse pharmacological activity as antioxidant, neuroprotective, antitumor, and anti-inflammatory drugs. Dimethoxycurcumin (DMC) is a metabolically stable analog of curcumin, and both drugs modify the activity of several epigenetic enzymes that affect DNA methylation and histone modifications. 5-hydroxymethylcytosine (5hmC) is an epigenetic mark involved in active demethylation and in gene expression regulation. The effect of curcuminoids on the activity and expression of TET enzymes involved in 5hmC oxidation and active demethylation in leukemia cells is unclear. In this study, we investigated the impact of curcumin and DMC on the activity and expression of the three isoforms of TET enzymes. We also studied their effect on global 5hmC and performed a genome-wide analysis of 5hmC distribution at the single CpG level using oxidative bisulfite sequencing, which can differentiate between 5hmC and 5-methylcytosine. Both curcumin and DMC increased the activity and the mRNA expression of the three isoforms of TET. Concordantly, they also increased the global 5hmC level in leukemia cells. Single CpG analysis showed that both drugs induced a 5hmC increase and active demethylation at gene promoters, CpG islands and shores, exons, introns, and intergenic regions. Curcumin induced a promoter 5hmC increase in 194 genes and promoter-active demethylation in 154 genes. On the other hand, DMC induced a promoter 5hmC increase in 173 genes and promoter-active demethylation in 171 genes. Our study identifies curcuminoids as active demethylators through the activation of TET enzymes and provides a rationale for testing their combination with DNA hypomethylating agents in leukemia animal models. Full article

This study investigates the performance of phenol–formaldehyde adhesives containing Eucalyptus lignin as an extender in their formulation. A commercial phenol–formaldehyde resin was used, and five different types of lignin were tested: (1) kraft lignin precipitated with carbon dioxide, (2) kraft lignin precipitated with sulfuric acid, (3) soda lignin precipitated with hydrochloric acid, (4) soda lignin precipitated with sulfuric acid, and (5) a second soda lignin where the wood underwent a phosphoric acid extraction process prior to alkaline extraction. The lignins were used both unmodified and activated through three different processes: hydroxymethylation, phenolysis in an acidic medium, and alkaline phenolysis. Adhesives were formulated with substitution percentages of the base resin ranging from 10% to 60%, in addition to a reference adhesive that contained no lignin. Wooden test specimens were manufactured to determine the tensile shear strength. Results indicate that best performance is achieved when lignins are activated through hydroxymethylation and when soda lignin is used. Under optimal conditions, it is possible to replace at least 45% of the base resin with activated Eucalyptus soda lignin, which represents a reduction of at least 30% in the cost of the final adhesive. This substitution results in a 46% increase in adhesive strength compared to the base adhesive (without lignin). These findings suggest that the valorization Eucalyptus soda lignin could have significant economic and environmental benefits. Full article

Flavor is a pivotal indicator influencing the meat quality and palatability of premium broiler chickens, shaped by multiple factors. The flavor differences among broiler chicken breeds/lines stem from the specificity of their metabolite profiles and volatile flavor compounds. This study aims to identify key metabolites and pathways that regulate flavor variations in high-quality broilers, providing data support and theoretical references for breeding superior broiler lines and developing technologies to enhance flavor quality. Breast Muscle tissue from 15-week-old roosters of the S3 and H lines (n = 6) was used as experimental material. Broad-targeted metabolomics and volatile metabolomics technologies were employed to identify key metabolites and volatile organic compounds (VOCs) influencing the flavor of breast meat in these two high-quality broiler lines. Broad-target metabolomics identified 167 differentially expressed metabolites (VIP > 1, p < 0.05) between the two strains, including 141 upregulated and 26 downregulated metabolites. These metabolites were primarily amino acids and their derivatives, and were significantly enriched in metabolic pathways such as ABC transporters (p < 0.05). Leu-Tyr, Ile-Tyr, Val-Leu, Val-Ile, and Tyr-Ala were identified as key metabolites influencing the flavor formation of breast meat from both high-quality broiler lines. Volatile metabolomics results identified 33 downregulated VOCs (VIP > 1 and p < 0.05). The flavor differences between the two strains primarily involved fatty and grassy flavor. Key flavor markers included 2-Nonanone, 2-Nonanone, 3-hydroxymethyl, 2-Methylheptanoic acid, and Hexanoic acid, butyl ester as the primary flavor markers. These significantly downregulated volatiles are formed through lipid oxidation and amino acid degradation pathways, respectively, collectively shaping the more pronounced fatty and grassy aromas in the S3 strain. Correlation analysis revealed a significant negative correlation between Met-Asn and Hexanoic acid, butyl ester, suggesting it may represent a key regulatory pathway influencing green flavor formation. In summary, this study elucidates key metabolites and pathways governing flavor differences in high-quality broiler rooster breast meat, providing a scientific foundation for poultry breeding, optimization of farming practices, and flavor regulation in meat products. Full article

We investigated the adsorption and aggregation properties of 2,13-bis(hydroxymethyl)-[7]thiaheterohelicene ([7]TH-diol) on the Ag(111) surface by scanning tunneling microscopy (STM) and molecular dynamics (MD) simulation. STM observation revealed that both racemic and enantiopure [7]TH-diol formed apparently similar “zigzag” chain structures. To elucidate the molecular arrangements in these structures, MD simulation successfully differentiates the formation mechanisms of these structures, demonstrating that hetero-chiral chains are stabilized primarily by van der Waals forces, whereas homo-chiral chains are stabilized through hydrogen bonding. The formation of homo-chiral chains is driven by the alignment of hydroxymethyl groups between the neighboring molecules, whereas the steric hindrance of helical skeletons affects chain growth. These findings highlight the critical role of inter-molecular interactions—particularly hydrogen bonding—in the self-assembly of helicene molecules. Full article

5-hydroxymethylfurfural (5-HMF) has been shown to exert neuroprotective effects in a global cerebral ischemia mouse model in our previous study, where it demonstrated antioxidant and anti-inflammatory properties. However, studies on its antidepressant mechanisms remain scarce. Since oxidative stress and neuroinflammation are closely associated with depression, this study investigated the antidepressant effects of 5-HMF, focusing on its potential inhibition of oxidative stress via the Nrf2 pathway and its role in microglial M1 polarization-mediated neuroinflammation. An acute depression mouse model induced by intraperitoneal injection of lipopolysaccharide (LPS) was utilized. Mice received 5-HMF (12 mg/kg) or an equal volume of vehicle via intraperitoneal injection 30 min prior to and 5 min after LPS administration. At 24 h post-modeling, behavioral tests (sucrose preference, forced swim, and open field tests) were conducted to evaluate the antidepressant effect of 5-HMF. Histological damage in the hypothalamus was assessed using Nissl staining and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining. Immunofluorescence was performed to evaluate M1 polarization of hypothalamic microglia. Oxidative stress damage was assessed by measuring malondialdehyde (MDA), carbonyl groups, and 8-hydroxy-2′-deoxyguanosine (8-OHdG) levels. Nrf2 DNA-binding activity was examined using an ELISA-based assay. The expression of inflammatory cytokines, Nrf2, and downstream antioxidant proteins was analyzed by ELISA kits and Western blotting. 5-HMF significantly alleviated LPS-induced depression-like behaviors, reduced hypothalamic neuronal damage, decreased oxidative stress, and inhibited microglial M1 polarization. It also regulated the expression of inflammatory cytokines (IL-1β, IL-6, TNF-α, IL-4, and IL-10) and activated the Nrf2 signaling pathway, enhancing nuclear translocation efficiency. Notably, these effects were significantly attenuated by the Nrf2 inhibitor brusatol. In conclusion, 5-HMF exerts neuroprotective effects by modulating Nrf2-mediated oxidative stress responses and suppressing microglial M1 polarization-driven neuroinflammation. These findings suggest that 5-HMF may provide therapeutic potential for alleviating depression symptoms induced by acute inflammation. Full article

Background/Objectives: Heterofunctional cationic polyester dendrimers derived from a 2-(bromomethyl)-2-(hydroxymethyl)propane-1,3-diol (BHP-diol) based AB₂C monomer were evaluated as efficient and biodegradable nonviral carriers for siRNA delivery. Methods: These dendrimers feature dual internal and external charge architectures, enabling precise control of charge distribution and siRNA interaction strength. Results: They achieved complete siRNA complexation at nitrogen-to-phosphate (N/P) ratios of 0.50–2.14 and provided up to 93% RNase protection, outperforming amino-functional scaffolds based on 2,2-bis(methylol)propionic acid (bis-MPA). In human (T98G) and murine (GL261) glioblastoma cells, the dendrimers exhibited minimal cytotoxicity while achieving 52–61% target protein knockdown, a two- to three-fold improvement over conventional polyester dendrimers, and approaching the silencing efficiency of the commercial Interferin^® reagent. Conclusions: The combination of high complexation efficiency, strong nuclease resistance, and excellent biocompatibility establishes these heterofunctional dendrimers as a new generation of precisely tunable, biodegradable vectors for therapeutic siRNA delivery. Full article

Tetrakis (Hydroxymethyl) Phosphonium chloride (THPC) in aqueous solution reacts with amines to form aminomethylenephosphines. The reaction was studied with piperidine, and THPC was used with PEI. The reaction with PEI leads to new polymers with phosphine groups (PEI-P) and phosphine oxide (PEI-PO) after oxidation by hydrogen peroxide. These polymers coordinate cations of transition metals, lanthanides and actinides. Full article

Cyanothioacetamide readily reacts with aromatic aldehydes in an aqueous–alcoholic medium in the presence of triethylamine as a catalyst, resulting in arylmethylene cyanothioacetamides (3-aryl-2-cyanothioacrylamides). The latter react with formaldehyde (HCHO), yielding N-(hydroxymethyl) derivatives. This work proposes a method for the preparation of new derivatives of N-(hydroxyalkyl)thioacrylamides. The details of the synthesis and spectral data are discussed. Biological effects are also considered as 2,4-D herbicide antidotes (safeners). Full article