Search Results (260)

Although mining activities are economically essential, they have led to significant environmental contamination, particularly in northern Chile. The discharge of untreated tailings has impacted coastal and soil ecosystems. This analysis investigates the biosorption and desorption of copper using the dried biomass of Lessonia berteroana, a brown alga, focusing on its reuse over multiple cycles. Biosorption experiments were conducted using synthetic copper sulfate solutions and real leachates (PLS) obtained from historically contaminated soils, obtaining maximum uptakes of 66.1 and 41.1 mg/g, respectively. In addition, four isotherm models—Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich (D–R)—were applied to describe equilibrium behavior. In synthetic systems, the Langmuir model described the data better. In the real matrix, the D–R model showed superior performance, indicating a more heterogeneous mechanism and a lower adsorption capacity. Desorption experiments, fundamental to evaluating the recyclability capacity of biosorbents, used HCl, HNO₃, H₂SO₄, and C₆H₈O₇ as desorbing agents. These experiments showed high initial efficiency (>95%) for all desorbents, and regeneration remained consistent over five cycles. In real PLS systems, nitric and citric acids maintained high desorption efficiencies with minimal degradation of biosorbent capacity. This study highlights the potential of L. berteroana as a sustainable biosorbent for copper recovery in both controlled and real-world applications, supporting its integration into circular economy strategies for mine-impacted environments. Full article

Somatic embryogenesis (SE) plays a pivotal role in the propagation and genetic improvement of coniferous trees; however, its efficiency is frequently limited by the reduced embryogenic potential of callus cultures. Here, we investigated the metabolic determinants underlying this phenomenon in Picea mongolica by conducting a comparative metabolomic analysis of embryogenic calli (EC) and non-embryogenic calli (NEC). We observed significant metabolic differences between EC and NEC using an integrated approach combining morphological observations and untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based metabolomics. EC exhibited increased central carbon metabolism, characterized by enhanced citrate cycle (TCA) flux, with significantly increased levels of the key TCA intermediates, citric acid and L-malic acid—18.8- and 3.6-fold higher, respectively, than those in NEC. Conversely, NEC displayed a divergent metabolic state, characterized by the accumulation of various amino acids and the activation of secondary metabolic pathways, especially alkaloid biosynthesis. These results indicate that embryogenic competence in P. mongolica is supported by a distinct metabolic program that prioritizes energy generation and efficient carbon-nitrogen allocation for biosynthetic processes. Conversely, the non-embryogenic state arises from a shift in metabolic resources toward secondary metabolism. These findings provide key metabolic insights and a theoretical basis for enhancing conifer SE systems. Full article

The consumption of energy and sports drinks is on the rise globally, exposing dental restorations to more frequent low-pH challenges, which affect degradation. This in vitro study simulated the combined effect of energy drink exposure and cyclic fatigue loading on the fatigue survival rate and flexural strength of three direct dental resin restorative materials with distinct chemistries: a bioactive ionic resin (Activa Presto), a giomer (Beautifil Flow Plus F00) and a conventional nano-hybrid composite (Tetric Ceram). Bar-shaped specimens (25 × 2 × 2 mm) were fabricated according to ISO 4049 and stored for 24 h in either distilled water or 0.2 M citric acid (pH ≈ 2.5), simulating an energy drink (n = 10/group). The samples then underwent chewing simulation (40 N, 100,000 cycles, 1.6 Hz) using a steel antagonist; surviving specimens were tested via three-point bending to determine their flexural strength. All the materials were affected by storage conditions: Activa Presto showed the lowest fatigue survival (20% in water; 0% in citric acid), Tetric N-Ceram moderate survival (40% in both solutions) and Beautifil Flow Plus F00 the highest and most stable survival (90% in water; 40% in citric acid). Among the surviving specimens, Tetric Ceram exhibited the highest flexural strength, followed by Beautifil Flow Plus F00 and then Activa Presto. Citric acid exposure and cyclic loading adversely affected the mechanical performance of all the materials within the limitations of this study. Full article

Salt–alkali stress is a major abiotic factor limiting plant growth. Dracocephalum moldavica L., an aromatic plant with medicinal and edible value, shows some potential for salt–alkali tolerance, but its response mechanisms remain unclear. In this study, physiological, transcriptomic, and metabolomic approaches were employed to compare the responses of D. moldavica seedlings to salt (NaCl/Na₂SO₄ = 1:1), alkali (NaHCO₃/Na₂CO₃ = 1:1), and mixed saline–alkali stress (NaCl/Na₂SO₄/NaHCO₃/Na₂CO₃ = 1:1:1:1). The results showed that all stress types increased the MDA content, with osmotic regulators and antioxidant enzymes helping mitigate damage. Alkali stress caused the most severe chlorophyll and photosynthetic damage. Transcriptomic analysis identified 12,838, 11,124, and 11,460 differentially expressed genes (DEGs) under salt, alkali, and mixed saline–alkali stress, respectively. Metabolomic analysis identified 1802, 1937, and 1794 differentially accumulated metabolites (DAMs) under each stress condition. Combined analysis revealed that all stresses activated pathways involved in galactose metabolism, the TCA cycle, pentose–glucuronic acid interconversion, and phenylpropanoid biosynthesis. Salt stress enhanced sucrose hydrolysis and lignification via INV and HCT. Alkali stress promoted the synthesis of 1-O-sinapoyl-β-D-glucose through COMT, improving antioxidant capacity and pH stability. Mixed saline–alkali stress activated genes related to sugar and energy metabolism, leading to the accumulation of xylitol and citric acid. These findings provide insights into D. moldavica’s mechanisms for tolerance, supporting its potential for saline–alkali land use. Full article

The fungal pathogen Candida albicans can infect diverse tissues, a reflection of its broad metabolic repertoire. The transcription factor Adr1 is required for utilization of several citric acid cycle intermediates that are found in tissue. Many Adr1-activated genes encode enzymes with well-defined roles in citrate metabolism or gluconeogenesis. Here, we focus on HGT17 (C4_01070W, orf19.4682), an Adr1-activated gene that encodes a possible citrate transporter. We provide two lines of evidence that HGT17 is a key functional target of Adr1. First, forced expression of HGT17 in an adr1Δ/Δ mutant improves growth on citrate as a carbon source. Second, hgt17Δ/Δ and adr1Δ/Δ mutants incubated in citrate medium present similar gene expression defects compared to the wild type. Noteworthy is down-regulation in both mutants of citric acid cycle genes, glycolysis/gluconeogenesis genes, and ergosterol synthesis genes. These common features may reflect a specific effect of citrate as an inducer of citric acid cycle enzymes or a global effect of carbon and energy limitation. In either case, the results argue that reduced HGT17 expression contributes substantially to the impact of an adr1Δ/Δ mutation on growth and gene expression. Full article

WO₃ nanorods were fabricated following electrochemical anodization of tungsten, under controlled hydrodynamic conditions, in electrolytes containing three distinct carboxylic acids: citric, tartaric and L-aspartic acids, to study the influence of these complexing agents on the morphology and arrangement of the oxide layers. The samples were characterized by FESEM, TEM and XRD, and electrochemical analyses (EIS and ECSA) to assess their potential as anode materials for lithium-ion batteries. This characterization showed the nanostructures anodized in the presence of tartaric acid exhibit uniform morphology and lower total charge transfer resistance associated with the nanostructured layer of WO₃ and cycling stability, resulting in more efficient electrochemical processes, better conductivity and stability, making these nanostructures promising for anodes in lithium-ion batteries. The cycling of the batteries was also conducted to understand the behavior of the nanostructures as anodes against metallic lithium. The results showed that the nanostructures analyzed in the presence of tartaric acid exhibited the best initial specific capacity, improving the capacity provided by the graphite ones. These samples also showed a good recovery after faster cycling. These findings demonstrate the effectiveness of complexing-agent-assisted anodization as a strategy for tailoring WO₃ nanostructures with enhanced electrochemical performance. Full article

Developmental programming, shaped by environmental and lifestyle stressors during prenatal life, is increasingly recognized as a major contributor to non-communicable diseases (NCDs) later in life. Oxidative stress, one of key mechanisms linking these stressors to fetal metabolomic reprogramming and disease pathogenesis, leaves measurable metabolomic signatures that reflect disrupted redox balance. Alterations in glucose, lipid, and amino acid metabolism and antioxidant response could reveal the main pathways driving NCD development. This review summarizes epidemiological studies that have investigated biochemical responses of the prenatal exposure to metals, air pollution, and tobacco smoke and e-cigarette vapor in maternal–placental–fetal compartments using a metabolomic approach. Summarized studies indicate that maternal exposure to metals primarily disrupts amino acid pathways related to one-carbon metabolism, glutathione synthesis, and oxidative stress defense, while air pollution, particularly fine particulate matter, mainly affects lipid oxidation, fatty acid β-oxidation, and amino acid and carbohydrate metabolism. Tobacco smoke and e-cigarette vapor induce widespread disturbances involving reduced citric acid cycle intermediates, altered acylcarnitines and phospholipids, and impaired antioxidant capacity, collectively promoting oxidative damage and inflammatory signaling. The identification of these metabolome alterations might contribute to a deeper understanding of the toxicity and biological impact of environmental stressors on offspring health. These results may eventually lead to the identification of early biomarkers and to the development of therapeutic strategies aimed at reducing NCD risk. Full article

In this paper, a simple hydrothermal approach is employed to prepare nitrogen-doped graphene quantum dots (N-GQDs) with controllable size and structural features, where citric acid and ethylenediamine served as the carbon and nitrogen precursors, respectively. The influence of hydrothermal temperature and duration on the structural features, surface chemistry, and electrochemical behavior of N-GQDs is systematically investigated. The capacitive behavior of N-GQD electrodes exhibits typical pseudocapacitive characteristics, primarily attributed to the surface functional groups. The NG-2 electrode (180 °C, 6 h) demonstrates a specific capacitance of 309.8 F g⁻¹ at 1 A g⁻¹ and maintains 98.1% of its initial capacitance after 8000 cycles, confirming excellent stability. Density functional theory (DFT) results demonstrate that the co-presence of graphitic and pyrrolic nitrogen induces a synergistic modulation of the electronic structure, resulting in improved charge-transfer kinetics and surface reactivity of N-GQDs compared to single-type nitrogen doping. Additionally, NG-2//activated carbon (AC)-asymmetric supercapacitor (ASC) achieves an energy density of 22.5 Wh kg⁻¹ at 500 W kg⁻¹ and maintains outstanding cycling stability. This work provides valuable insights into the design and application of N-GQDs for advanced energy storage devices. Full article

Background: Normal spermatogenesis in Mongolian horses depends on the mitotic division of spermatogonia, two successive meiotic divisions, and the morphological transformation of spermatids into mature spermatozoa. The MEI1 gene is involved in the meiosis cycle and is required for normal chromosome association during meiosis. Previous studies have shown that alternative splicing of MEI1 may promote spermatogenesis in Mongolian horses. In this paper, the regulatory effects of different MEI1 alternative splicing events on Mongolian horse spermatogenesis are investigated. Results: In this study, two overexpressed lentiviral vectors with mutually exclusive exon (MXE) and skipped exon (SE) events of MEI1 were constructed and successfully used to infect Sertoli cells. After 72 h of viral infection, the expression of MEI1 was higher in the SE event than in the MXE event (p < 0.001), as shown by fluorescence quantification; transcriptomics and metabolomics were then used to screen and annotate the differential genes and metabolites, and 193 differentially expressed genes (comprising 109 genes, such as MEI1, and 84 genes with upregulated and downregulated expression, respectively) and 11,360 differentially expressed metabolites (comprising 7494 and 3866 metabolites with upregulated and downregulated expression, respectively) were screened. Differential genes and metabolites were mainly enriched in several metabolic pathways related to spermatogenesis. Differential genes such as IL31RA, ATP2B3, and CASQ2 were highly expressed in SE events, while IL11, PRLR, and CCR7 were highly expressed in MXE events. Metabolites such as folic acid and spermine were highly expressed during SE events, while citric acid and glutathione were highly expressed during MXE events. This suggests that both MXE and SE events of the MEI1 gene can promote the activity of the spermatogenesis signaling pathway. Conclusions: The MXE and SE splicing events of the MEI1 gene may influence spermatogenesis by regulating the expression of spermatogenesis-related genes and metabolites. These findings provide a theoretical foundation for further investigations into the regulatory mechanisms of different alternative splicing events in Mongolian horse spermatogenesis. Full article

Prostate cancer (PC) remains a major cause of cancer deaths in men. The serum biomarker prostate-specific antigen (PSA) lacks specificity in distinguishing clinically significant PC (sPC) from insignificant PC (isPC), leading to overdiagnosis and overtreatment. Although magnetic resonance imaging (MRI) improves detection, it is expensive, is time-consuming, and may involve inter-reader discrepancies. Recently, metabolomics, which has a high analytical sensitivity and broad molecular-feature coverage, has emerged as a promising tool to risk-stratify PC. This review examined studies of blood and urine metabolomics for sPC biomarker identification. Significant metabolite changes in sPC patients often involved fatty acid metabolism, sphingolipid metabolism, glycolysis, the citric acid cycle, purine/pyrimidine metabolism, and tyrosine/phenylalanine metabolism. Specifically, more than one study reported increased lactate and phenylalanine levels, along with decreased tyrosine, xanthine, and histidine levels, in sPC patients. Several metabolic panels outperformed serum PSA in predicting sPC, particularly when combined with clinical factors. Among these, two urine-based tests may have higher accuracy in predicting sPC than most current commercially available assays. However, direct comparison between studies may be inappropriate due to methodological heterogeneity, the variability in biospecimen types, inconsistent use of digital rectal examinations, and different sPC definitions and predictive endpoints. Most relevant studies were of small sample size or lacked external validation. Despite these challenges, metabolomics-based liquid biopsies show strong potential for improving sPC detection. Future research should focus on protocol standardization, MRI integration, absolute metabolite quantification, and validation in large and independent cohorts to enhance model credibility. Full article

Background: Glioblastoma (GB) is the most common primary brain tumor, with poor prognosis, significant neurological symptoms, and near-universal recurrence. Biomarker development is often limited by the scarcity of tumor tissue available for study. Noninvasive serum-based profiling offers potential to improve outcomes. Purpose: This study examined serum proteomic and metabolomic profiles pre- and post-concurrent chemoirradiation (CRT) to identify associations with patient outcomes and molecular classification, and to explore relevant signaling and metabolic pathways. Methods: Serum samples from 109 GB patients, obtained prior to and following completion of CRT, were analyzed with each patient serving as their own control, using a SOMAScan^® proteomic assay (7289 proteins) and metabolomics (SECIM, 6015 compounds). Clinical data were obtained through chart review. Proteomic and metabolomic changes were examined at baseline (prior to CRT) and in alteration (pre- vs. post-CRT) for their association with overall survival (OS), progression-free survival (PFS), MGMT, and IDH status. Cox models, gene set enrichment analysis (Hallmark, GSEA), and Kaplan–Meier survival analysis were used. Results: Several hundred proteins and metabolites were associated with OS and PFS. MGMT status was known in 60% and IDH in 38% of patients. Pre-CRT DLST (HR 11.7, p < 0.001, adj p = 0.01) was the only protein significantly associated with OS. Pre-CRT, and higher 7-HOCA was linked to worse OS (HR 1.3) and PFS (HR 1.5), while increased p-cresol was associated with improved OS (HR 0.8) and PFS (HR 0.9). Kaplan–Meier analysis based on signal alteration post-CRT vs. pre-CRT, revealed superior OS with lower DLST and MSR1 and superior PFS with higher PGAM2 and ATG5, and lower 7-HOCA. Pathway analysis linked improved PFS to fatty acid metabolism, citric acid cycle, and purine biosynthesis. MGMT and IDH class comparisons revealed associations primarily with amino acid and fatty acid metabolism. Both MGMT methylation and IDH mutation correlated with increased PLAG12B expression, with significance only for MGMT (p < 0.001). IDH mutation was associated with decreased MSR1 (p = 0.047) and p-cresol (p < 0.001). Conclusions: Serum-based fatty acid and purine metabolism pathways are associated with OS and PFS in GB. 7-HOCA and p-cresol emerged as potential biomarkers linked to treatment response and molecular subtype. These findings support further investigation of noninvasive biospecimens for clinically actionable biomarkers in GB. Full article

This study investigates the effectiveness of citric acid as a salt crystallization inhibitor aimed at improving the durability and mechanical performance of concrete exposed to marine environments. The goal is to evaluate whether the addition of citric acid can mitigate the deterioration of concrete caused by salt crystallization during wet–dry cycles and simulated wave impacts. The novelty of this work lies in the experimental demonstration that a simple and environmentally friendly organic compound can effectively reduce salt-induced damage in marine-exposed concrete. Concrete samples were subjected to repeated wet–dry cycles and simulated marine wave impacts to assess changes in their physical and elastic properties. Variations in P-wave and S-wave velocities, Young’s modulus, and the effects of salt crystallization within the concrete matrix were evaluated through acoustic measurements. Results show that citric acid significantly reduces internal cracking, stiffness loss, and salt accumulation, leading to enhanced structural integrity and greater resistance to environmental stressors. These findings highlight the potential of citric acid as a sustainable additive for improving the long-term durability and mechanical stability of concrete structures in marine environments. Full article

Plant-based fermented coconut yogurt, valued for its functional properties, requires transformation into a shelf-stable powder, necessitating carriers to overcome particle stickiness and preserve probiotic viability. The objective of this study was to investigate the influence of polysaccharide carriers (maltodextrins DE 2, 10, and 19, and resistant dextrin) on processing efficiency, physicochemical stability, and lactic acid bacteria (LAB) viability. The feed, standardized to 15% total solids (initial LAB counts of 8.54 log CFU/g), was spray-dried at a 120 °C inlet temperature and a 65 °C outlet temperature. The drying condition reduced LAB viability by two log cycles regardless of the tested carriers. Maltodextrin DE 19 showed the highest powder yield, the lowest water activity, and a higher water solubility index. No significant differences in bulk density, pH, titratable acidity, and lactic acid content were observed among samples. Low-DE maltodextrins (DE 2 and 10) demonstrated significantly higher retention of sensitive malic and citric acids compared to DE 19. The current findings suggested that high-DE carriers provided beneficial effects on physical processing via kinetic shell formation, while low-DE carriers were able to protect against the loss of small organic acids. Overall, the study lays a foundation for spray-dried carrier development for coconut yogurt. Full article

Environmental problems arising from conventional production models have posed a significant challenge in the search for renewable sources as raw materials for the production of everyday chemical compounds through more sustainable alternatives. The objective of the present work was the electrochemical synthesis of organic acids from the liquid of the natural and technical cashew nut shell (CNSLn and CNSLt), employing chronopotentiometry using a potentiostat and a graphite working electrode. Two concentrations (0.01–0.1% v/v) of CNSLn and CNSLt, two concentrations of NaOH as supporting electrolyte (0.125–2 M), and two current densities (40–60 mA/cm²) were tested in the experiments. Organic acids were detected and quantified by HPLC. To characterize the redox processes occurring in the constituents of CNSL, spectroelectrochemical analysis (FTIR–cyclic voltammetry), FTIR, and chronoamperometry were performed. The maximum concentrations obtained in the treatments were: acetic acid (828.86 mg/L), lactic acid (531.78 mg/L), and formic acid (305.4 mg/L), while other acids present in lower concentrations included oxalic, propionic, citric, and malonic acids. Voltammetry characterizations showed three irreversible oxidation processes in the anodic wave during the first cycle, indicating that the first process involved the formation of the phenoxy radical, the second process the formation of hydroquinones and benzoquinones, and the third process the cleavage of the aromatic ring and the aliphatic chain to form the organic acids. Furthermore, another oxidation pathway was observed, consisting of a fourth process in the second voltammetry cycle, corresponding to the nucleation of the phenoxy radical, evidenced as the formation of the C–O–C bond visible at 1050 cm⁻¹ in the infrared spectrum. From this route, a polymer was formed on the electrode surface, which limited the yield of organic acid synthesis. Finally, this research provides new insights in the field of electrochemistry, specifically in the synthesis of organic acids from CNSL as a renewable feedstock, with the novelty being the production of oxalic, propionic, citric, and malonic acids. Full article

The cryopreservation and transplantation of germline stem cells (GSCs) have become the key to conserving fish genetic resources and safeguarding species diversity. This study aimed to investigate the effects of post-mortem temperature and time on the preservation of oogonial stem cells (OSCs) in the marine fish Paralichthys olivaceus. OSCs remained viable after fish death, and they remained viable and could be cultured after storage at 19 °C for 15 h and at 4 °C for 24 h. Combined transcriptomic and metabolomic analysis was used to identify the pathways leading to OSC death. Several genes were differentially expressed in the ovarian tissue post-mortem, with the most enriched pathways being ferroptosis, fatty acid metabolism/biosynthesis, glutathione metabolism, citric acid cycle (TCA cycle), and arachidonic acid metabolism signaling pathways. Genes related to ferroptosis, such as vdac2, p53, and slc7a11, as well as metabolites such as adrenic acid and arachidic acid, can serve as reliable biomarkers for evaluating the viability of post-mortem OSCs. These findings provide valuable insights and theoretical support for the effective use of post-mortem GSCs and enhance strategies for germplasm resource conservation in fish. Full article