Aldehyde dehydrogenase 2 (ALDH2) is a key mitochondrial enzyme that detoxifies reactive aldehydes including formaldehyde, thereby mitigating their genotoxic effects. While ALDH2 deficiency exacerbates bone marrow (BM) failure in Fanconi anemia models, its role under exogenous genotoxic stress is less clear. In this study, we used Aldh2[-/-] mice to investigate how ALDH2 deficiency impacts hematopoiesis following treatment with busulfan (BSF), sublethal total body irradiation (TBI), or a combined (BSF+TBI) regimen. Under BSF or TBI monotherapy, Aldh2[-/-] mice exhibited moderate increases in DNA damage, measured by γH2AX expression in hematopoietic stem and progenitor cells (HSPCs), with a mild decline in BM cell engraftment, compared to Aldh2[+/+] controls. However, BSF+TBI treatment triggered more severe HSPC DNA damage confirmed by concordant γH2AX and 53BP1 elevation, and a sharper decline in mature hematopoietic cells. Notably, this dual stress significantly upregulated DNA repair and metabolic adaptation genes, including Ccno, Pold4, Taf1c, Npr2, and Aldh18a1. These results suggest that BSF+TBI treatment drives advanced DNA damage and compensatory gene expression shifts in the absence of ALDH2. We conclude that the impact of ALDH2 deficiency on hematopoiesis is dependent on the severity of exogenous stress. TEASER ABSTRACT: The ALDH2 rs671 loss-of-function polymorphism is carried by 30-40% of East Asian individuals, yet its hematopoietic consequences under clinical genotoxic stress remain poorly understood. Using Aldh2[-/-] mice, we demonstrate that ALDH2 deficiency increases DNA damage in hematopoietic stem and progenitor cells (HSPCs) following busulfan (BSF) or total body irradiation (TBI) monotherapy, without altering mature hematopoietic cell populations or long-term repopulating capacity. However, combined BSF+TBI treatment unmasks a clear, stress-severity-dependent phenotype: Aldh2[-/-] mice exhibit significantly greater HSPC apoptosis and DNA damage confirmed by concordant γH2AX and 53BP1 elevation, and more severe peripheral blood cytopenias. Transcriptomic analysis reveals compensatory upregulation of DNA repair pathways and Aldh18a1, suggesting a metabolic adaptation to mitigate genotoxic burden. These findings establish ALDH2 deficiency as a latent hematopoietic risk factor with direct implications for personalizing conditioning regimens in ALDH2 rs671 carriers undergoing hematopoietic stem cell transplantation.

The majority of metabolic pathways rely on the production of activated electrophilic intermediates, e.g., coenzyme-A esters, and their chemical structures and abundances are central to understanding enzyme function and biochemical mechanisms. However, most electrophilic metabolites are lost in traditional metabolomic analysis and thus remain poorly characterized. Here, we introduce a biochemical probe, O-(trimethylammoniobutyl)-hydroxylamine (TAMOHA), that enables comprehensive profiling of electrophilic species such as coenzyme-A esters, ketones, and aldehydes. TAMOHA incorporates a highly nucleophilic hydroxylamine that reacts quickly with electrophilic species upon tissue lysis, trapping them as stable derivatives that feature a tetraalkylammonium moiety whose constitutive charge and characteristic MS2 fragmentation fingerprint enable their highly sensitive detection. Using TAMOHA to survey the electrophilomes of E. coli, C. elegans, and mice revealed several thousand electrophilic metabolites, most of which have not been characterized. We then demonstrate trapping of electrophilic metabolites with TAMOHA in the context of specific biochemical pathways, confirming previously proposed functions of two fatty acid metabolism enzymes, detecting formaldehyde production in mice, and providing new insights into the biosynthesis of ascaroside pheromones in C. elegans. We anticipate that use of TAMOHA for the profiling of electrophilic species will help clarify enzyme function and uncover previously elusive biochemical mechanisms in a wide range of biological systems.

Ovum Pick-Up (OPU) enables efficient, repeated oocyte retrieval from elite dairy goats, making it a critical technology for accelerating genetic progress through in vitro embryo production (IVEP) in dairy goat breeding. However, the limited quality and quantity of retrieved oocytes often restrict its overall efficiency. Melatonin (MT) has been known to regulate mammalian reproductive physiology and the ovarian microenvironment, but its specific effects across different follicle-stimulating hormone (FSH) superovulation protocols to enhance oocyte yield and quality remain unclear. This study investigated the effects of MT supplementation (20 mg/dose, total 120 mg/goat across 6 injections) on oocyte recovery in dairy goats subjected to three different FSH injection protocols (incremental, constant, and decremental). Following in vitro fertilization, embryo development and pregnancy rates after embryo transfer (ET) were subsequently evaluated. MT supplementation significantly increased the total number of recovered oocytes (P < 0.05), with the constant FSH protocol yielding optimal outcomes. MT increased blastocyst rates (P < 0.05), although the improvement of cleavage and fresh ET pregnancy rates were not significant. MT elevated both estrogen and progesterone levels in the serum of dairy goats (P < 0.05). Further researches to determine the mechanism of melatonin effects was performed by evaluation of serum hormones and oxidative stress related molecule, follicular fluid metabolomics, and ovarian transcriptomics. Multi-omics analysis revealed that MT significantly altered the follicular fluid metabolic profile, particularly affecting antioxidant and steroid hormone metabolism (Epigallocatechin, Quercetin 3-O-Xylosyl-Rutinoside, Hexahydrocurcumin, Protocatechuic Aldehyde, Isodityrosine, Pregnanediol, 16-Ketoestradiol), and regulated antioxidant and steroid hormone-related genes (GSTM1, MGST2, RXFP1, 3βHSD, HSD17B7, and PAQR7). Furthermore, ovarian redox homeostasis was enhanced by increasing glutathione peroxidase (GSH-Px) activity and reducing malondialdehyde (MDA) levels (P < 0.05). Overall, MT exerts multidimensional beneficial effects on ovarian microenvironment to enhance oocyte developmental competence. Combining a constant FSH protocol with MT achieves optimal superovulation efficiency, providing a robust strategy for advancing overall IVEP efficiency in dairy goat.

Tissue under- and over-processing in the histology laboratory, while decreasing in frequency, is still a valid concern and typically results from user or instrument error. This study evaluated the effects of extended exposure of histological tissues to processing reagents on specimen quality, including embedding, microtomy, histochemical staining, and immunohistochemistry (IHC). All specimens were fixed in neutral buffered formalin for 3-5 weeks prior to processing except for a subset of organs which underwent prolonged fixation for 1 year. Although overprocessing is traditionally associated with tissue hardening, brittleness, and shrinkage, these effects are often noted when fixation timing is not clearly defined. To simulate processing delays, specimens were subjected to an additional 24 h in absolute ethanol, xylene, molten paraffin, or a heated embedding station. Extended exposure to these reagents did not result in observable morphologic changes. Embedding quality, microtomy performance, and histochemical staining were consistent across all experimental conditions. Additionally, IHC antigenicity was largely preserved under most conditions. However, reduced or absent immunoreactivity was observed in select markers in organs fixed for 1 year, consistent with prior reports of fixation-related antigen masking and deterioration of antigenic sites. Unexpectedly, extended exposure to ethanol, xylene, or paraffin did not independently compromise IHC performance in adequately fixed specimens.

Hydrazine (N2H4) is recognized as a hazardous substance with severe implications for human health, ecological balance, and food security. To address this, we present HCA-IN, a novel xanthene-derived fluorescent probe engineered for the highly sensitive and specific recognition of N2H4. HCA-IN was constructed through a Knoevenagel condensation reaction between a xanthene aldehyde derived from 4-(diethylamino)salicylaldehyde and 1,3-indanedione. Mechanistically, the recognition relies on a N2H4-induced Michael addition followed by a specific cleavage event, which dynamically alters the intramolecular charge-transfer (ICT) pathway, eliciting both a remarkable fluorescence amplification and a distinct naked-eye color shift. In a THF/10 mM PBS system (8:2, v/v; pH 7.0), HCA-IN exhibited a rapid response to hydrazine, reaching equilibrium within 120 s, and delivered a broad linear working range (1-50 µM) alongside an exceptionally low limit of detection (LOD) of 6.31 nM. The probe showed excellent selectivity against prevalent metal ions, amino acids, various amines, and biological small molecules. Standard-addition experiments in lake water gave recoveries of 97.2-106.8% with relative standard deviations below 4.22%, indicating good accuracy and reproducibility. In addition, smartphone-assisted RGB analysis enabled portable quantitative detection of hydrazine, demonstrating excellent linearity (0-60 µM, R[2] = 0.99666) for ΔRGB against N2H4 levels. This study provides an efficient and convenient fluorescence sensing platform for trace hydrazine detection in environmental analysis.

A novel cell membrane-based biomimetic screening platform was developed for in vitro discovery of potential anti-cancer compounds. HepG2 cell membranes with biological recognition functions were stably immobilized onto aldehyde-functionalized mesoporous silica nanoparticles (HepG2-CM@AFMSNs) to enable affinity capture of potential anti-hepatocellular carcinoma (anti-HCC) compounds from herbal extracts. Specifically, the aldehyde-functionalized mesoporous silica was conjugated with HepG2 cell membranes via glutaraldehyde crosslinking, which could effectively prevent membrane shedding and preserve the inherent bioactivity. Natural products captured by HepG2-CM@AFMSNs were dissociated from the cell membranes, and structural identification was performed on eluents using matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS). The reproducibility and stability of HepG2-CM@AFMSNs were significantly improved by optimizing the conditions for cetyltrimethylammonium bromide (CTAB) removal, ultrasonic cell disruption, and membrane immobilization. As a result, four potential anti-HCC compounds, i.e., tenacissoside H, scutellarin, emodin, and baicalin, were screened from three herbal extracts, and their anti-proliferative effects on HepG2 cells were verified by MTT assay. Overall, the developed HepG2-CM@AFMSNs combined with MALDI MS analysis demonstrated significant advantages in screening natural products with anti-cancer potential from herbal extracts.

Disulfide rebridging chemistry is a promising strategy for site-specific modification of native antibodies. Current disulfide rebridging strategies using homofunctional rebridging reagents typically favor either rapid conjugation with compromised stability or stable linkage formation with reduced reaction efficiency. Here, we report a kinetically differentiated rebridging strategy using a class of heterotrifunctional rebridging reagents, 5-fluoro-4-(phenylsulfonyl)pyridine derivatives, which can efficiently rebridge reduced disulfide bonds in antibodies to construct diverse types of antibody conjugates under physiological conditions. The kinetically differentiated bis-thiol-reactive system enables rapid initial thiol substitution followed by proximity-accelerated subsequent conjugation, in which the spatially vicinal cysteine thiols generated upon disulfide reduction sequentially replace fluorine and phenylsulfonyl groups on the pyridine derivatives, thereby combining efficient disulfide rebridging with high linkage stability. The resulting pyridyl aldehyde in the rebridged antibodies enables conjugation of functional probes or payloads, yielding multifunctional antibody conjugates. Based on this method, we have constructed antibody-fluorophore conjugates, demonstrating high plasma stability and efficient internalization into target cell lines, and antibody-drug conjugates (ADCs) with potent cytotoxicity in vitro. This method provides robust linkage stability and expands the toolkit of disulfide bridging reagents for constructing stable antibody conjugates and disulfide-containing biomolecules under mild conditions.

Sauce-flavor baijiu derives its characteristic aroma from the unique geography of the Chishui River Basin and a multi-round fermentation process. Aldehydes are key odorants contributing fruity, roasted, and nutty notes, yet their regional distribution and evolution across the seven production rounds remain poorly characterized. We developed a GC-FID method to quantify aldehydes in eight commercial baijiu samples from seven production regions and monitored acetaldehyde, acetal, and furfural across the seven rounds of baijiu. The method showed excellent linearity (R[2] ≥ 0.996), low detection limits (0.02-0.30 mg/L) and high precision (RSD ≤ 3.12%). Regional aldehyde profiles differed significantly (P < 0.05). Multivariate analysis clearly separated samples by origin and identified the three compounds as high-VIP concentration variables (VIP > 1). Across rounds, acetaldehyde and acetal exhibited a rise-fall-rise pattern, while furfural increased steadily. Acetaldehyde was more sensitive to region and processing conditions, furfural showed cross-regional consistency, and acetal was intermediate. These findings provide a chemical basis for origin authentication, round-based grading and process optimization in sauce-flavor baijiu production.

Multicomponent reactions provide powerful modularity for peptide functionalization, but their application to lysine residues remains limited by the low efficiency of direct primary-amine-based activation pathways under peptide-compatible conditions. Here we report a secondary-amine relay strategy for lysine-directed multicomponent functionalization of peptides. In this approach, salicylaldehyde derivatives, arylboronic acids, and a cyclic secondary amine are combined to generate a transient electrophilic intermediate, which is subsequently intercepted by the ε-amine of lysine-containing peptides. By separating electrophile generation from direct lysine activation, this relay protocol improves the efficiency of lysine modification while retaining the modularity of multicomponent chemistry. Mechanistic experiments, isolated intermediate studies, kinetic comparisons, and density functional theory calculations support a pathway involving secondary-amine-mediated intermediate formation followed by lysine capture. The method enables modification of diverse bioactive peptides, incorporation of drug-derived and fluorescent aldehyde or boronic acid components, and lysine-lysine stapling using bifunctional aldehydes. The reaction is further compatible with automated and parallel solid-phase peptide modification workflows, providing rapid access to libraries of lysine-functionalized peptide conjugates. This study provides a practical secondary-amine relay platform for modular peptide functionalization and expands the utility of multicomponent chemistry in automated peptide synthesis.

In this research, twelve derivatives of pyranochromene were synthesized using multicomponent reactions of euparin, aldehydes, 1,3-dicarbonyl compounds, and activated acetylenic compounds. These procedures occurred in water at ambient temperature, employing APTES@SiO2@Fe3O4-SO3H magnetic nanoparticles (MNPs). The DPPH radical scavenging assays were employed to evaluate the antioxidant properties of some produced pyranochromenes. A comprehensive assessment of the antibacterial efficacy of the synthesized compounds was conducted utilizing the disk diffusion method. This assessment was conducted utilizing two distinct strains of Gram-negative bacteria alongside Gram-positive bacteria. The method employed for synthesizing pyranochromenes was distinguished by a combination of several beneficial attributes. Overall, the developed methodology combines mild reaction conditions, an aqueous reaction medium, efficient catalyst recovery, enhanced reaction kinetics, and good product yields, demonstrating its potential as a practical and sustainable approach for the synthesis of pyranochromene derivatives with biologically relevant properties.

Methacrolein (MACR), a major primary oxidation product of isoprene, plays an essential role in secondary organic aerosol (SOA) formation. Here, we investigate the effect of SO2 levels and relative humidity (RH) on the SOA formation from the MACR/OH photooxidation system. From a series of experiments performed in an indoor smog chamber, the aerosol chemical composition was analyzed using gas chromatography-mass spectrometer (GC-MS) and Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR). The experimental results indicate that the particle mass concentration, maximum particle number concentration, geometric mean diameter and the SOA yields increased with increasing initial SO2 concentration under high (61 %-65 %), medium (20 %-22 %) and low (9 %-12 %) RH conditions. The SOA mass concentration increased as RH decreased in the presence of SO2, which could be attributed to reduced wall loss of hydrophilic species and the weak dilution of aerosol acidity under low RH conditions. Furthermore, we found that the presence of SO2 can affect the changes in the formed SOA mass concentration under different RH conditions. IR spectra results revealed the formation of organosulfate and inorganic sulfate compounds in the particle phase, and the formation mechanism of the detected SOA products is proposed. The results of this study provide a deeper understanding of SOA formation under complex polluted environments.

Titanium dioxide (TiO2) has garnered extensive research attention due to its broad applicability in the degradation of volatile organic compounds (VOCs). The polymorph and composition of TiO2 significantly influence its photocatalytic activity. In this study, the crystal phase transition from TiO2(B) to TiO2(A) and TiO2(R) was achieved by adjusting the annealing temperature, and the influence of these structures on its photocatalytic activity was systematically investigated. Interestingly, the photocatalytic activity order of single-phase catalysts followed the sequence of TiO2(A)> TiO2(R) > TiO2(B), and a hump-shaped activity trend was observed, with two activity peaks corresponding to the diphase combinations of TiO2(B)/TiO2(A) and TiO2(A)/TiO2(R), respectively. Specifically, the TiO2(A)/TiO2(R) photocatalyst exhibited the highest formaldehyde degradation efficiency (100 %) within 45 min, with the mineralization ratio of 70.63 %. The enhanced activity predominantly was attributed to the existence of heterophase junctions, leading to the boosted the separation efficiency of charge carriers photoinduced. More interestingly, the crystal phase variations resulted in the selective generation of reactive oxygen species. This study provides insights for the development of photocatalysts with diverse polymorphs for improved activities and presents substantial potential to the improved efficiency in the decomposition of VOCs.

Microbial consortia are essential for the degradation of complex hydrocarbon mixtures in coastal environments, yet the functional basis of consortium performance rarely resolved at strain level. In this study, we employed a Plackett-Burman experimental design to rationally assemble and optimize a synthetic consortium for the degradation of medium-grade crude oil in a sand-seawater microcosm. Six strains were selected: Stutzerimonas stutzeri CBC1 and CBC2, S. balearica GOM11, Pseudomonas sp. CBC3, Halomonas litopenaei GOM23 and Enterobacter kobei GOM24. After 45 days, the consortium removed 15.72% of total hydrocarbons relative to the abiotic control, with markedly higher fraction-specific removal determined by GC-MS: 94.7% of phenanthrene, 63.1% and 41.0% of the C8-C27 and C18-C27 aliphatic fractions respectively. Comparative genomic analysis revealed a non-uniform distribution of catabolic functions consistent with metabolic complementary. Stutzerimonas and Pseudomonas strains carried ring-hydroxylating dioxygenases (nah/nag-like clusters) together alkane-degrading alcohol/aldehyde dehydrogenases (alkJ, alkH), whereas H. litopenaei GOM23 and E. kobei GOM24 encoded alternative long-chain alkane-hydroxylating systems (ladA). GOM24 further carried an expanded repertoire of ABC transporters and oxidative-stress genes (ahpC/ahpF), consistent with a role in substrate uptake and stress tolerance rather than in primary ring cleavage. Enzymatic assays supported this partitioning, catechol 1,2-dioxygenase activity was confined to the same four strain that encoded the gene and was highest in CBC1 and GOM11 (0.0472 and 0.0443 U·mg[-][1] protein, respectively). No genome carried the classical alkB alkane-monooxygenase, pointing to alternative and partially redundant alkane-oxidation routes. By combining statistically guided assembly with comparative genomics and targeted enzyme assays, this work identifies a six-strain combination that removes more crude oil than the full eleven-isolate community and resolves how its catabolic functions are partitioned among strains.