Search Results (381)

Low temperatures limit the yield and stability of autumn-sown oats; thus, investigating cold resistance physiological responses is essential. In this study, we compared a cold-resistant variety (‘Aiwo’) and a cold-sensitive variety (‘Hewang’). ‘Aiwo’ exhibited a significantly higher overwintering survival rate (96.9%) and superior physiological traits, including elevated levels of soluble proteins, proline, putrescine, unsaturated fatty acids, and glutathione, alongside greater ATPase activity and reduced ROS levels. Exogenous putrescine application suggested a potential role of Put in alleviating lipid peroxidation. Metabolomic analysis showed that the arginine–proline and cysteine–methionine pathways were enriched among DAMs associated with ‘Aiwo’, accompanied by the accumulation of stress-protective metabolites. These metabolic changes may contribute to improved energy balance and membrane stability under low-temperature conditions. Our findings suggest that proline, putrescine, and glutathione are candidate physiological indicators associated with the cold-resistant phenotype, which may facilitate future screening of cold-resistant oat germplasm. Full article

Microbial reduction of soluble selenium oxyanions is a sustainable strategy for remediating selenium-contaminated environments, yet the molecular mechanisms underlying selenite tolerance in the genus Rhodococcus remain poorly understood. In this study, we investigated the proteomic adaptation of the highly tolerant strain Rhodococcus qingshengii PM1 under high-concentration selenite stress (50 mM Na₂SeO₃) using a data-independent acquisition (DIA)-based quantitative proteomics approach. A total of 3335 proteins were identified, and 3310 proteins were retained for downstream analysis. Comparative proteomics revealed 1411 differentially expressed proteins, including 972 upregulated and 439 downregulated proteins in the selenite-treated group. These changes indicate extensive systems-level proteomic reprogramming and support a growth–defense trade-off strategy. Strain PM1 strongly upregulated ferredoxin and multiple respiratory-chain- and oxidoreductase-associated proteins, suggesting a ferredoxin-associated electron-transfer network that may contribute to Se(IV) transformation and intracellular redox adjustment. In parallel, proteins involved in sulfur assimilation, cysteine/methionine and selenocompound metabolism, ergothioneine biosynthesis, GSH-associated metabolism, Trx/MSH thiol-redox systems, peroxidase/Ohr-Prx detoxification, metalloid/oxyanion resistance, urease-associated pH adaptation, DNA repair, and cell-envelope remodeling were induced, indicating activation of multilayered defense and homeostasis mechanisms. Conversely, proteins associated with central carbon metabolism, carbohydrate uptake, and ribosome-dependent translation were repressed, suggesting reduced growth investment and energy conservation under severe selenite pressure. Overall, this study provides a systems-level proteomic framework for understanding Se(IV) resistance in R. qingshengii PM1 and identifies candidate targets for future functional validation, strain engineering, and selenium/metal(loid) bioremediation. Full article

Sulfur-containing amino acids (SCAA) and their metabolites constitute an integrated metabolic network essential for central nervous system (CNS) function. In mammals, sulfur metabolism links one-carbon metabolism, the methionine cycle and the transsulfuration pathway, thereby connecting nutrient availability with redox regulation, methylation reactions, neurotransmitter synthesis and cellular adaptation to stress. Among these metabolites, methionine, cysteine, glutathione, taurine, homocysteine and hydrogen sulfide play key roles in neuronal physiology, mitochondrial homeostasis, synaptic plasticity and antioxidant defense. Alterations in SCAA metabolism have been increasingly associated with neurological and neurodevelopment disorders, which share common features such as oxidative stress, mitochondrial dysfunction, altered glutamatergic signaling, impaired methylation capacity and neuroinflammation. These pathological mechanisms are also observed following exposure to toxic metals, suggesting the existence of convergent pathways between environmental neurotoxicity and neurological diseases. Several studies showed that chronic exposure to arsenic, mercury, cadmium, lead, and other toxic metals disrupts sulfur amino acid homeostasis by affecting methionine remethylation, transsulfuration activity, glutathione synthesis and reactive sulfur species production. Due to sulfur-containing metabolites possessing antioxidant and metal-binding properties, these pathways are also involved in adaptive detoxification response. However, sustained disruption of sulfur metabolism may compromise neuronal resilience and increase vulnerability to neurological dysfunction. This narrative review integrates current evidence on the physiological roles of SCAA in the CNS, and examines how toxic metals disrupt sulfur metabolic pathways. By combining findings from experimental studies, human data and exploratory transcriptomic analyses, we propose that disruption of SCAA homeostasis represents a mechanistic link between environmental metal exposure and increased vulnerability to neurological disease. Full article

Acinetobacter baumannii, a multidrug-resistant pathogen of critical priority within the ESKAPE group, poses a significant threat to global healthcare, particularly in the context of nosocomial infections. Its pathogenesis is mediated not only by antibiotic resistance determinants but also by a complex repertoire of secreted virulence factors. However, comprehensive characterization of the A. baumannii secretome remains methodologically challenging due to spectral overlap in complex biological matrices. In this study, we applied a hybrid approach integrating size-exclusion chromatography with Raman spectroscopy to deconvolute the cell-free supernatant of A. baumannii. Chromatographic fractionation into seven fractions reduced spectral complexity and enabled the identification of unique metabolic profiles. Fraction 3 exhibited a distinct composition, containing specific markers for phosphatidylserine (~1724 cm⁻¹), cysteine, phosphatidylinositol, and DNA (~770–806 cm⁻¹), as well as CH₂ groups of lipids and amino acids (~1450–1456 cm⁻¹), while lacking signals corresponding to methionine-containing compounds, nucleic acid backbones, and polypeptide backbones characteristic of other fractions. Analysis revealed distinct biochemical specialization across fractions: Fraction 2 was enriched in glutamine/asparagine-associated signals (~990, ~998 cm⁻¹), Fraction 4 contained a unique carotenoid marker (~1154 cm⁻¹), Fraction 6 exhibited a phenylalanine-specific peak (~1104 cm⁻¹), and Fraction 7 demonstrated the highest intensity of cysteine-containing protein, nucleotide, and phospholipid signals. These findings open new avenues for the discovery of biomarkers associated with virulence and antibiotic resistance in A. baumannii. Full article

To further investigate altitude-associated variations in gut microbiota and serum metabolites of plateau zokors (Eospalax baileyi) and elucidate their adaptive mechanisms to high-altitude environments, we performed fecal metagenomic sequencing and serum metabolomic profiling (Q200 platform) on individuals from high (3700 m, n = 6) and low (2700 m, n = 6) elevations, followed by integrated analysis of microbial and metabolomic datasets. Results indicated that in high-altitude plateau zokors, the relative abundance of Firmicutes decreased, while that of Bacteroidota increased. The dominant genera within this group were identified as Bacteroides and unclassified members of the Lachnospiraceae family. Moreover, the abundances of Bacteroides and unclassified members of the Muribaculaceae family increased with elevation. At the species level, seven fully annotated differentially abundant taxa were identified: Candidatus Amulumruptor caecigallinarius, Schaedlerella arabinosiphila, Muribaculum gordoncarteri, Heminiphilus faecis, Prevotellamassilia timonensis, Staphylococcus aureus, and Bacteroides graminisolvens. KEGG enrichment analysis indicated significant upregulation (p < 0.05) of energy supply pathways, such as oxidative phosphorylation, and antioxidant-related pathways, including β-alanine and lysine metabolism, in the high-altitude group. Conversely, cysteine and methionine metabolism pathways were markedly downregulated (p < 0.05). Serum levels of ursodeoxycholic acid and tauroursodeoxycholic acid (TUDCA) were significantly elevated (p < 0.05), while deoxycholic acid (DCA) levels decreased (p < 0.05). In conclusion, the composition and function of gut microbiota, along with serum metabolite profiles, differ significantly (p < 0.05) between plateau zokors from different altitudes. Through synergistic interactions between gut microbiota and host metabolites, plateau zokors develop adaptive mechanisms that integrate energy metabolism, oxidative stress response, intestinal barrier integrity, and mucosal immunity. This ultimately facilitates their acclimatization to high-altitude extreme environments characterized by hypoxia and low temperatures. Full article

This experiment investigated the effects of two rearing systems, cage and free-range, on growth performance, serum biochemical parameters, slaughter performance, cecal microbiota, and hepatic metabolism of yellow-feathered broilers. A total of 240 healthy 21-day-old Liangfenghua yellow-feathered male broilers with similar body weight were randomly assigned to a cage group (LY) and a free-range group (SY), with 10 replicates per group and 12 birds per replicate. All birds were fed the same diet until 63 days of age. Compared with the LY group, the SY group had significantly lower final body weight, average daily gain, and abdominal fat percentage (p < 0.05), while average daily feed intake and feed-to-gain-ratio were significantly higher (p < 0.05). The Shannon and Simpson indices of the cecal microbiota were significantly higher in the SY group (p < 0.05), and the genera Bacteroides, Lactobacillus, Rikenella, and Oscillibacter were specifically enriched. A total of 560 differential metabolites were identified by liver non-targeted metabolomics, and these metabolites were significantly enriched in the necroptosis, cysteine and methionine metabolism, thiamine metabolism, and amino sugar and nucleotide sugar metabolism pathways (p < 0.05). Correlation analysis between cecal microbiota and liver metabolites revealed that the differentially abundant bacterial genera showed significant negative correlations with multiple amino acid metabolites in the liver. In conclusion, the free-range rearing system reduced the growth performance of yellow-feathered broilers but enriched specific bacterial genera, increased gut microbiota diversity, and modulated host amino acid metabolism and energy homeostasis through the “gut microbiota–liver” axis, ultimately inducing an adaptive metabolic state characterized by reduced abdominal fat deposition and remodeling of hepatic metabolic pathways. Full article

This study evaluated the effects of dietary sulphur-containing amino acid (SAA) levels provided during the early (1–28 d) and late (29–63 d) growth stages on production traits and feather follicle gene expression in 63-day-old Jiangnan white goslings. A total of 288 one-day-old male goslings were assigned to a 2 × 2 factorial design with two early SAA levels (0.64% and 0.87%) and two late SAA levels (0.62% and 0.74%), which created four treatments: Dd (low–low), Dg (low–high), Gd (high–low), and Gg (high–high). All measurements were performed on 63-day-old birds. Final body weight was significantly affected only by early SAA levels (p = 0.03), with the high early groups (Gd and Gg) showing a 3% higher weight (3.99 vs. 3.88 kg) than the low early groups. Late SAA levels had no effect on growth but markedly reduced breast muscle cooking loss (p < 0.01) from 26.64% (low late) to 22.70% (high late), which represents a 15% relative improvement in water-holding capacity. A significant early × late interaction (p = 0.03) indicated that late high SAA levels partially compensated for early deficiency. High late SAA levels also slightly reduced dry matter digestibility (73.45% → 73.16%, p = 0.03), while high early SAA levels increased crude ash digestibility (33.59% → 35.66%, p = 0.04). The Dg treatment (low early + high late) caused significantly elevated serum low-density lipoprotein (2.06 vs. 1.42–1.58 mmol/L) and uric acid (348.15 vs. 243.60–294.97 μmol/L), which indicates metabolic stress (p < 0.01 and p = 0.02 for interaction). Transcriptomic analysis of feather follicles from the Gg and Gd groups (both receiving identical high early SAA supplementation) identified 121 differentially expressed genes, including the downregulation of MAT1 (cysteine/methionine metabolism) and upregulation of GHRHR (neuroactive ligand–receptor interaction) in Gg, providing a molecular basis for improved feather growth. q-PCR validated five selected genes. In conclusion, final body weight is determined by early SAA supply, while late SAA supplementation improves meat juiciness, but abrupt increases from low to high SAA levels cause metabolic disturbances. Under this test conditions, The optimal feeding strategy is 0.87% SAAs (1–28 d) followed by 0.74% SAAs (29–63 d). Full article

Prediction models for standardized ileal amino acid digestibilities (SIAADs) of sorghums in yellow-feathered chickens have not been previously reported. This study characterized the chemical composition of 10 sorghum samples from different sources, assessed their SIAADs in medium-growing yellow-feathered chickens, and subsequently developed and validated prediction models based on chemical composition and amino acid profiles. A total of 276 Tianluma roosters (60 d of age) were randomly assigned by body weight (average 1.32 kg per bird) to 11 dietary treatments, including a nitrogen-free diet (NFD) group and 10 sorghum-based diet groups. Each treatment included 6 replicate cages, with 4 birds per replicate cage for the sorghum-based diet groups and 6 birds per replicate cage for the NFD. Birds were fed the experimental diets from d 63 to 67, after which ileal digesta were collected to determine SIAADs of 10 sorghum samples. Data from 9 sorghum samples were used to establish prediction equations using stepwise regression, while the remaining sample was used for model validation. Sorghum source significantly influenced (p ≤ 0.002) the SIAADs of most amino acids. Arginine (Arg) exhibited the highest standardized ileal digestibility (SID) (68.2%), whereas tyrosine (Tyr) showed the lowest value (49.0%). Eighteen preliminary prediction models were developed for the SIDs of valine (Val, R² = 0.981, p = 0.001), methionine (Met, R² = 0.978, p < 0.001), isoleucine (Ile, R² = 0.983, p < 0.001), leucine (Leu, R² = 0.981, p < 0.001), threonine (Thr, R² = 0.748, p = 0.016), phenylalanine (Phe, R² = 0.981, p < 0.001), lysine (Lys, R² = 0.988, p < 0.001), histidine (His, R² = 0.988, p = 0.004), Arg (R² = 0.986, p < 0.001), tryptophan (Trp, R² = 0.934, p < 0.001), aspartic acid (Asp, R² = 0.986, p < 0.001), serine (Ser, R² = 0.980, p < 0.001), glutamic acid (Glu, R² = 0.988, p < 0.001), glycine (Gly, R² = 0.898, p = 0.007), alanine (Ala, R² = 0.983, p < 0.001), cysteine (Cys, R² = 0.968, p = 0.003), Tyr (R² = 0.898, p = 0.001), and proline (Pro, R² = 0.944, p = 0.002). The models for the SIDs of Lys, His, and Glu exhibited the highest coefficients of determination (R² = 0.988, p ≤ 0.004), whereas the model for the Thr SID exhibited the lowest fit (R² = 0.748, p = 0.016). Except for Leu and Tyr, the predicted values of the remaining amino acids were generally consistent with the determined values in the validation sample. These preliminary models provide a basis for estimating amino acid digestibilities in sorghums for medium-growing yellow-feathered chickens. Full article

Plant quality is strongly influenced by environmental conditions, including the presence of micronutrients and potentially toxic elements in the soil. This study aimed to evaluate the effect of soil-applied fluorine on the content of exogenous (essential) and endogenous (non-essential) amino acids in black radish roots and the aerial biomass of narrow-leaved lupine. The following essential amino acids were identified: histidine, threonine, arginine, lysine, tyrosine, leucine, phenylalanine, isoleucine, methionine, and valine. The group of endogenous amino acids comprised cysteine, proline, serine, glutamic acid, aspartic acid, glycine, and alanine. Increasing fluorine application generally enhanced the accumulation of both essential and endogenous amino acids in lupine shoots and radish roots. The strongest stimulatory effect on the synthesis of most amino acids was observed at the lowest fluorine doses, i.e., 20 mg F kg⁻¹ soil for narrow-leaved lupine and 100 mg F kg⁻¹ soil for black radish. By contrast, the concentrations of certain endogenous amino acids, such as aspartic acid, glutamic acid and proline in radish roots and aspartic acid in lupine shoots, were highest at intermediate fluorine contamination levels. Moreover, the maximum contents of tyrosine and cysteine in lupine aerial parts were recorded under the highest fluorine dose. Overall, protein derived from black radish exhibited a higher nutritional value than that of narrow-leaved lupine. The results obtained show that simulated soil contamination with fluoride stimulates amino acid synthesis in both plants. The research enables a better assessment of the quality and nutritional value of crops grown under conditions of environmental contamination, and helps to explain the mechanisms by which plants defend themselves against chemical stress. The research suggests that moderate fluoride contamination causes changes in nitrogen metabolism, increasing amino acid production, which may be a defence mechanism in plants against stress. Full article

Methionine and cysteine are the principal sulfur-containing proteinogenic amino acids, playing pivotal roles in protein structure, function, and cellular metabolic regulation. The biosynthetic machinery of these amino acids is intricate and exhibits distinct evolutionary divergence across species. This review comprehensively summarizes the biosynthesis of cysteine and methionine in model organisms ranging from Escherichia coli and yeast to plants and Homo sapiens. Specifically, we examine the metabolic interconversion and the transition of roles between these two amino acids during de novo synthesis. Furthermore, we dissect the physiological significance of the transsulfuration pathway in mammals, which utilizes methionine as a precursor for cysteine biosynthesis. Full article

Obesity is a major global health challenge characterized by chronic low-grade inflammation, oxidative stress, and an increased risk of cardiometabolic disorders. Although sex-related differences in inflammatory and redox biomarkers have been reported in obese populations, the molecular mechanisms underlying this heterogeneity remain incompletely understood. In this study, we applied a proteomics-based approach to investigate urinary extracellular vesicles from 45 obese individuals (BMI 30–40 kg/m²; age 50–70 years) in order to identify molecular signatures associated with metabolic dysregulation. Shotgun proteomics analysis performed by nanoLC–MS/MS enabled the identification of 3822 proteins. Hierarchical clustering of proteomic profiles revealed two distinct molecular groups, predominantly enriched in males (Group I) and females (Group II). Label-free quantitative analysis identified 466 differentially abundant proteins between the two clusters. Functional enrichment analysis highlighted pathways associated with immune response, metabolic regulation, and redox homeostasis, including glycolysis/gluconeogenesis, lysosome activity, leukocyte transendothelial migration, and glutathione, cysteine and methionine metabolism. Notably, proteins related to ferroptosis were enriched, suggesting the involvement of iron-dependent oxidative cell death mechanisms in the metabolic imbalance observed in a subset of subjects. Furthermore, the non-enzymatic glycosylation of urinary proteins was significantly higher in Group I compared with Group II (p = 0.0002), indicating increased formation of advanced glycation products in individuals with a more pronounced pro-oxidant state. Preliminary follow-up data suggested a higher incidence of pathological events, including cardiovascular complications, among individuals belonging to Group I. Overall, these findings demonstrate that urinary proteomic profiling can identify distinct molecular phenotypes among obese individuals and highlight oxidative stress, ferroptosis, and protein glycation as potential determinants of metabolic vulnerability, supporting the use of non-invasive proteomic approaches for improved risk stratification in obesity. Full article

Ergothioneine (EGT), a naturally occurring amino acid derivative with potent antioxidant and cytoprotective properties, is widely applied in the food, cosmetic, and medical industries. Traditional production methods are limited by high costs, low efficiency, and environmental concerns, so microbial fermentation serves as a sustainable alternative for EGT production. In this study, Escherichia coli BL21 (DE3) was employed as the chassis strain. First, a basic EGT-producing engineered strain was constructed by heterologously expressing the egtB gene from Methylobacterium pseudosasicola along with the egtD and egtE genes from Mycobacterium smegmatis. This initial strain achieved a yield of 84.84 ± 1.64 mg/L of EGT in shake-flask cultures. To enhance production, solubility-enhancing tags were introduced to improve the soluble expression of the key enzymes, and metabolic pathways were rationally engineered to strengthen the supply of essential precursor amino acids. These modifications led to the development of a high-yield EGT strain. After optimizing the fermentation process, the best results were achieved using a medium with glycerol as the carbon source, 0.5 g/L of histidine, 1.5 g/L of methionine, and 1.0 g/L of cysteine, along with induction at 25 °C using 0.2 mM IPTG for 120 h. Under these conditions, the final EGT yield reached 385.70 ± 4.86 mg/L. The engineered strain for EGT synthesis and optimized fermentation strategy developed in this study offer a useful basis for further process development. Full article

This study established an untargeted metabolomic approach based on ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) to investigate differences in metabolites and lipid composition of lycopene-enriched egg yolk at different enrichment levels and conventional egg yolks. Principal component analysis and hierarchical clustering revealed clear unsupervised discrimination and separation among the control group and two treatment groups. Metabolomic analysis identified 14 differential metabolites, including amino acids, which were associated with 13 metabolic pathways such as cysteine and methionine metabolism. Lipidomic analysis revealed 48 significantly altered lipids, including phospholipids and glycerides. The results demonstrated that lycopene supplementation significantly altered the metabolic and lipid profiles of egg yolks. Specifically, lycopene enrichment upregulated phospholipid synthesis and increased the levels of antioxidant-related metabolites. This study confirms that untargeted metabolomics and lipidomics can effectively identify potential biomarkers in egg yolks with varying lycopene enrichment levels, offering new insights and a scientific basis for nutritional research and metabolic mechanism analysis of functional eggs. Full article

This study developed a two-stage, explainable machine learning framework to predict 18-month MMSE-based cognitive status from baseline multimodal data in community-dwelling older adults in Japan. A hierarchical design was used in which Stage 1 distinguished cognitively Normal participants from those with any abnormality (Possible Mild Cognitive Impairment (MCI) or Impaired), and Stage 2 further separated Possible MCI from Impaired within the abnormal subgroup. Both an Imbalanced-Learn Random Forest and a penalized logistic regression baseline were trained under Leave-One-Out Cross-Validation, yielding fair discrimination in Stage 1 (Random Forest AUC = 0.72, accuracy = 0.71; logistic regression AUC = 0.71, accuracy = 0.76) and apparently strong separability in Stage 2 (Random Forest AUC = 0.95, accuracy = 0.96; logistic regression AUC = 0.82, accuracy = 0.92) in a small sample size with high class imbalance. SHapley Additive exPlanations (SHAP) with TreeExplainer for Random Forest and LinearExplainer for logistic regression were used to identify interpretable biomarkers at each stage though feature attribution. In Stage 1, both models highlighted renal and systemic metabolic markers (e.g., creatinine, uric acid, blood urea nitrogen), amino acid and redox-related metabolites (including D-serine, D-amino acid proportions, L-asparagine, alanine, L-glutamic acid, cysteine, methionine sulfoxide), and wearable-derived activity variability (e.g., fluctuation coefficients and steps per minute), with the Simpson index of gut microbiome diversity also contributing in the logistic model. In Stage 2, the models converged on a distinct signature involving glucose and albumin, uric acid and uridine, choline and carnitine, multiple amino acids (such as phenylalanine, proline, ornithine, tryptophan, threonine, and short-chain amino acids), oxidative/energy markers (niacinamide, methionine, methionine sulfoxide, ergothioneine), hematologic indices, and high-MET activity fluctuation metrics. Collectively, these results support a stage-dependent, multisystem view of cognitive aging in which broad renal–metabolic, amino acid, and behavioral vulnerabilities characterize early abnormality, whereas more pronounced alterations in energy metabolism, nucleotide and choline pathways, oxidative stress, and activity irregularity accompany progression from Possible MCI to Impaired status. By combining routine clinical chemistry, targeted metabolomics, gut microbiome diversity, and wearable-derived behavioral measures within an explainable AI framework, this two-stage approach illustrates a scalable, biologically grounded strategy for stage-aware risk stratification and monitoring of cognitive decline in community settings. Full article

A two-year field experiment was conducted in Tengchong, Yunnan, to evaluate the effects of tobacco monoculture (TM) and maize relay intercropping with tobacco (TIM) on subsequent tobacco growth and the rhizosphere microenvironment. Results showed that TIM significantly increased plant height by 11.8% and maximum leaf length by 12.4% at the vigorous growth stage without reducing yield. Although leaf chloride content increased and the potassium-to-chloride ratio decreased, both remained within high-quality ranges. Relay-cropped silage maize yielded 4.86 t·hm⁻², adding 1.70 × 10⁴ CNY·hm⁻². TIM reduced nitrogen accumulation in aboveground tobacco and temporarily lowered soil organic matter and available potassium, while increasing acid phosphatase, peroxidase, and urease activities. Soil bacterial α-diversity increased, with enrichment of beneficial genera, including Candidatus Solibacter, Talaromyces, and Penicillium. Metabolomics identified 1043 metabolites, with upregulation of galactinol, N-acetyl-L-tryptophan, and 3-dehydroshikimic acid, enriched in cyanogenic amino acid and cysteine–methionine pathways. PLS-PM and Mantel analyses indicated that relay-cropped maize indirectly regulates nutrient availability via microbial and metabolic pathways. These results show that maize relay intercropping creates a soil “legacy effect,” shifting the system from direct nutrient competition to microbially mediated nutrient buffering. Full article