Search Results (14,451)

The underlying structural features of the mismatch between catalytic and cytostatic properties in L-asparaginase from Rhodospirillum rubrum (RrA) and three of its mutants were investigated. The rationale for selecting the specific mutations (RrA_{A64V, E67K}; RrA_{R118H, G120R}; RrA_{E149R, V150P, F151T}) is to elucidate the role of inter-subunit interaction in RrA and its impact on catalytic efficiency and stability. Bioinformatic modeling revealed a predominantly negative surface charge on RrA with limited positive charge clusters in the vicinity of the interface region. Thus, some negatively charged groups were replaced with positively charged ones to enhance the electrostatic interactions and stabilize the enzyme quaternary structure. RrA_{A64V, E67K} and RrA_{R118H, G120R} additionally contained an N-terminal 17-amino acid capsid peptide derived from the bacteriophage T7 (MASMTGGQQMGRGSSRQ), which could potentially affect the conformational stability of theenzymes. Circular dichroism (CD) spectroscopy was applied to the kinetic parameters analysis of Asn hydrolysis and showed that native RrA displayed a V_max of 30 U/mg and a K_M of 4.5 ± 0.5 mM. RrA_{E149R, V150P, and F151T} exhibited a substantially increased V_max of 57 U/mg. The catalytic efficiency of V_max/K_M also improved compared to the native enzyme: the V_max/K_M increased from approximately 7 U/mg × mM⁻¹ (for the native enzyme) to 9 U/mg × mM⁻¹ for Mut3. Other mutants exhibited less pronounced changes. Thermo-denaturation studies allowed us to determine the phase transition parameters of the RrA variants in comparison with commercial reference sample EcA. RrA_{A64V, E67K} and RrA_{R118H, G120R} exhibited the most favorable phase transition parameters, with melting temperatures (T_m) of 60.3 °C and 59.4 °C, respectively, exceeding that of the wild-type RrA (54.6 °C) and RrA_{E149R, V150P, F151T} (52 °C). The EcA demonstrated a slightly superior thermal stability, with a T_m of 62 °C. The mutations showed a significant effect on protein stability during trypsinolysis. Therefore, RrA_{E149R, V150P, F151T} showed higher resistance (45% activity remaining after 30 min of trypsin exposure) compared to the native RrA retained 20% activity. EcA preparations exhibited lower stability to trypsinolysis (losing over 90% activity in 15 min). The cytostatic effects were evaluated using MTT assays against K562 (leukemic) and A549 (lung carcinoma) cell lines. The MTT assays with K562 cells revealed that RrA_{E149R, V150P, F151T} (IC₅₀ of 10 U/mL) and RrA_{R118H, G120R} (IC₅₀ of 11.5 U/mL) exhibited superior antiproliferative activity compared to native enzymes RrA (IC₅₀ of 15 U/mL) and EcA (24 U/mL). RrA_{E149R, V150P, F151T} showed the most significant improvement in cytostatic activity. The results obtained indicate that the substitutions in RrA_{E149R, V150P, F151T} resulted in the improvement of the enzyme biocatalytic properties and an increase in the resistance to aggregation and trypsinolysis. This highlights the role of electrostatic interactions in stabilizing the oligomeric structure of the enzyme, which eventually translates into an improvement in cytostatic efficiency and antiproliferative forces. Full article

Benzo[a]pyrene is an important indicator of polycyclic aromatic hydrocarbons pollution that exhibits complex atmospheric dynamics influenced by meteorological factors and suspended particulate matter (SPM). Herein, the factors influencing B(a)P concentration were elucidated by analyzing the monthly environmental data for Kyoto, Japan, from 2001 to 2021 using an improved association rule algorithm. Results revealed that B(a)P concentrations were 1.3–3 times higher in cold seasons than in warm seasons and SPM concentrations were lower in cold seasons. The clustering performance was enhanced by optimizing the K-means method using the sum of squared error. The efficiency and reliability of the traditional Apriori algorithm were enhanced by restructuring its candidate itemset generation process, specifically by (1) generating C₂ exclusively from frequent itemset L₁ to avoid redundant database scans and (2) implementing the iterative pruning of nonfrequent subsets during L_k → C_k+1 transitions, adding the lift parameter, and eliminating invalid rules. Strong association rules revealed that B(a)P concentrations ≤ 0.185 ng/m³ were associated with specific meteorological conditions, including humidity ≤ 58%, wind speed ≥ 2 m/s, temperature ≥ 12.3 °C, and pressure ≤ 1009.2 hPa. Among these, changes in pressure had the most substantial impact on the confidence of the association rules, followed by humidity, wind speed, and temperature. Under the influence of high SPM concentrations, favorable meteorological conditions further accelerated pollutant dispersion. B(a)P concentration increased with increasing pressure, decreasing temperature, and decreasing wind speed. Principal component analysis confirmed the robustness and accuracy of our optimized association rule approach in quantifying complex, nonlinear relationships, while providing granular, interpretable insights beyond the traditional methods. Full article

Ru-based catalysts manifest unparalleled hydrogen evolution reaction (HER) performance, but the hydrolysis of Ru species and the accumulation of corresponding reaction intermediates greatly limit HER activity and stability. Herein, Ru nanoparticle assemblies modified with single Mo atoms and supported on N-incorporated graphene (referred to as MoRu-NG) are compounded via hydrothermal and chemical vapor deposition (CVD) methods. The incorporation of single Mo atoms into Ru lattices modifies the local atomic milieu around Ru centers, significantly improving HER catalytic behavior and stability. More specifically, MoRu-NG achieves overpotentials of 53 mV and 28 mV at 10 mA cm⁻², with exceptional stability in acidic and alkaline seawater solutions, respectively. In MoRu-NG, Ru atoms have a special electronic structure and thus possess optimal hydrogen adsorption energy, which indicates that excellent HER activity mainly hinges upon Ru centers. To be specific, the d-electron orbitals of Ru atoms are close to half full, giving Ru atoms moderate bond energy for the assimilation and release of hydrogen, which is beneficial for the conversion of reaction intermediates. Moreover, the incorporation of single Mo atoms facilitates the formation of O and O’-bidentate ligands, significantly enhancing the structural stability of MoRu-NG in universal-pH seawater electrolysis. This work advances a feasible construction method of hexagonal octahedral configuration (Ru-O-Mo-N-C) and provides a route to synthesize an efficient and stable catalyst for electrocatalytic HER in universal-pH seawater. Full article

Soil health is an important concept in promoting sustainable agriculture and food security, yet the absence of universally accepted benchmarks limits its utility in assessing soil function. This study explored the use of Conservation Reserve Program (CRP) soils as a potential benchmark to quantify the soil health gap (SHG) in Faribault County, Minnesota. Using the Soil Management Assessment Framework (SMAF), we evaluated physical, chemical, biological, and nutrient soil health indicators to derive a combined overall score that was used to quantify the SHG (i.e., benchmark soil minus test soil) between CRP and corn-based agricultural production (AP). Three paired farms were assessed, each consisting of CRP tall grass prairie established in 2001 and adjacent long-term AP. The results showed higher overall SMAF scores in CRP soils, with a mean SHG of 0.09. Land use had a strong influence on overall scores, largely driven by biological indicators such as soil organic carbon, microbial biomass carbon, and β-glucosidase activity. However, the SMAF demonstrated limited applicability in CRP systems, potentially under-representing their soil health status due to the SMAF’s agricultural emphasis and lack of ecosystem-specific factors such as pH. Full article

In this study, a Bi₂O₃-TiO₂/PAC ternary composite photocatalyst was successfully synthesized via a hydrothermal method, employing powdered activated carbon (PAC) as the support and using bismuth nitrate and tetrabutyl titanate as raw materials. The external morphology, microstructure, elemental composition, and optoelectronic properties of the catalyst were characterized by XRD, SEM, TEM, XPS, UV-Vis DRS, and BET analyses. The photocatalytic activity of the composite toward the degradation of malachite green (MG) was systematically evaluated under various conditions. The results revealed that the composite exhibited excellent photocatalytic activity, achieving a degradation efficiency of up to 99%. Apart from extremely acidic or alkaline conditions, MG removal efficiency increased with a rising solution pH. Moreover, the photocatalyst exhibited excellent adaptability and stability in the presence of coexisting inorganic anions and humic substances, indicating its broad potential for practical applications. Reactive-species-trapping experiments indicated that superoxide radicals (·O₂⁻) were the primary active species in the degradation process, with hydroxyl radicals (·OH) and photogenerated holes (h⁺) acting synergistically. Moreover, the catalyst maintained over 90% removal efficiency after five consecutive cycles, demonstrating its excellent stability and reusability. This work provides a promising strategy and theoretical foundation for the efficient photocatalytic treatment of MG-contaminated wastewater. Full article

Objective: This study investigated gait and cognitive dual-task costs under a dual-task paradigm that was more challenging than the traditional tasks used in research. Methods: A total of 43 18–25-year-old male and female student athletes were recruited (20 asymptomatic concussed athletes who suffered at least one concussion 2.79–7.92 months before testing, 23 never concussed). Athletes performed a complex rapid decision-making and executive function computerized task while walking continuously and maintaining a predetermined speed on a non-motorized treadmill (6.5 km/h). The outcome measures were gait and cognitive dual-task costs. Results: Repeated-measures ANOVAs were conducted to evaluate group differences. Pearson correlations were conducted to evaluate the association between dual-task costs and concussion injury variables. The results showed that both groups experienced greater difficulty with dual-task performance related to gait, whereas only the concussion group exhibited poorer cognitive performance under the dual-task condition (both not significant). The significant correlation between time since injury and gait dual-task cost (r = −0.72, p < 0.001) indicated that athletes with a more recent concussion increased their gait speed whilst athletes with an older concussion reduced their gait speed during the dual-task. Moreover, the cognitive dual-task cost was significantly correlated to symptom recovery (r = 0.461, p = 0.047), suggesting that a longer recovery time from concussion is associated with an increased dual-task cost. Conclusions: While dual-task gait alterations were common to both groups, only individuals with a history of concussion showed specific cognitive impairments under dual-task conditions. The observed associations between dual-task costs and both time since injury and symptom recovery underscore the potential of complex dual-task assessments to provide nuanced insights into post-concussion recovery trajectories and to detect subtle, lingering deficits. Full article

Soil acidification is a significant threat to agricultural sustainability, particularly in paddy fields, where acidic conditions can limit crop productivity and soil health. This study aimed to explore the combined effects of alkaline amendments—lime, magnesia, and silicon fertilizer—on the acid-neutralizing capacity (ANC) of paddy soils and the rice yield, with the objective of identifying effective strategies to mitigate soil acidification and enhance agricultural productivity. From 2018 to 2021, a four-year field trial in Hunan tested lime, magnesia, and silicon fertilizers. Soil samples (0–20 cm depth) were collected once post-harvest in 2021 to evaluate the cumulative treatment effects. After four years, the control soil pH was 6.12. Lime and light magnesia treatment increased it to 6.70 and 6.99, respectively. Silicon fertilizer showed no significant difference (pH 6.05). ANC analysis revealed the following anti-acidification capacity ranking: light magnesia > lime > control > silicon fertilizer. Light magnesia boosted the rice yield by 13.02% over the control. Statistical analyses indicated a significant positive correlation between the soil acid-neutralizing capacity and pH (ANC4.0 = 7.53 × pH − 30.00, R²adj = 0.70; ANC5.0 = 6.96 × pH − 37.49, R²adj = 0.58). The rice yield was correlated with exchangeable magnesium (yield = 0.42 × Ex-Mg + 24.54, R²adj = 0.44). The continuous application of lime and light magnesia enhanced the nutrient availability and soil anti-acidification, with light magnesia also improving the rice yield. These findings provide insights to aid in enhancing soil quality and agricultural productivity in acid-affected regions. Full article

Cold stress disrupts broiler homeostasis, and a single intervention may be insufficient for protection. This study examined the effects of early cold conditioning (25 ± 1 °C for 3 h at 5 days) and glutamine (Gln) supplementation on broiler thermotolerance during a 16 ± 1 °C cold challenge at 35 days. A 2 × 3 factorial design assigned 360 Cobb-500 broilers to six treatments (six replicates/treatment, ten birds/replicate) with three Gln levels (0%, 0.3%, and 0.5%) and two temperature conditions: standard temperature and a 7 °C reduction at 5 days old. Supplementing with 0.3% and 0.5% Gln and cold conditioning improved growth performance (p < 0.05), except for feed intake during the grower-finisher phase and overall growth with cold conditioning alone. Adding 0.3% and 0.5% Gln enhanced hemoglobin, total protein, albumin, triiodothyronine (T₃), thyroxine (T₄), antioxidant capacity, catalase (CAT), superoxide dismutase (SOD), heat shock protein 70 (HSP70), interleukin 2 (IL2), IL10, IL4, interferon-γ (INF-γ), and troponin-T levels (p < 0.05). Cold conditioning influenced packed cell volume, T₃, T₄, CAT, HSP70, IL10, INF-γ, and troponin-T levels (p < 0.05). Diet-temperature interaction influenced growth, antioxidant, and immune responses, but not hematological or biochemical indicators. Overall, dietary Gln at 0.3% and 0.5% and early cold conditioning may serve as complementary strategies to mitigate cold stress in broilers. Full article

Lipid metabolism and oxidative stress are major contributors to ocular diseases, including drusen formation and photoreceptor damage. Aster-B, encoded by GRAMD1B, mediates the non-vesicular transport of cholesterol and carotenoids and is highly expressed in the human eye, though its specific ocular functions remain unknown. We investigated Aster-B’s role in ARPE-19 cells, a model of the retinal pigment epithelium (RPE), using CRISPR/dCas9 to generate an Aster-B-expressing cell line. Aster-B expression significantly improved cell survival under oxidative stress induced by hydrogen peroxide (H₂O₂) and was associated with the activation of the p53 and TGFβ signaling pathways, indicating a role in modulating stress responses. To confirm its lipid transport activity, we treated cholesterol-depleted cells with carotenoids and tracked their localization. In Aster-B-expressing cells, carotenoids accumulated in mitochondria, while in control cells, they remained in other cellular compartments. Under oxidative stress, mitochondrial carotenoid levels declined in Aster-B-expressing cells but not in control cells. Interestingly, carotenoids enhanced survival in control cells exposed to H₂O₂ but had a detrimental effect in Aster-B-expressing cells, suggesting that carotenoid function is context and location dependent. These findings highlight Aster-B’s role in coordinating lipid transport and stress responses in the RPE, with implications for oxidative stress-related eye diseases. Full article

The biocompatibility and long-term stability of stainless steel orthodontic devices are critically influenced by their corrosion resistance in the oral environment. This study evaluates the effect of three artificial saliva formulations—Afnor (pH 7.64), Fletcher (pH 8.07, fluoride-containing), and Fusayama/Meyer (pH 6.34, acidic)—on the surface integrity and chemical behavior of 316L stainless steel over 7 and 28 days. A multi-technique approach was employed, including SEM imaging, EDX elemental mapping, XRF analysis, microhardness testing (Vickers), and the monitoring of key physico-chemical parameters (pH, conductivity, salinity, and TDS). The results indicate that Afnor saliva maintains alloy stability with minimal surface damage while Fusayama/Meyer promotes pitting corrosion and selective leaching of Fe and Ni. Fletcher saliva led to the formation of crystalline corrosion products and significant surface hardening, likely due to the interaction of fluoride with the passive layer. Microhardness values increased across all samples after 28 days, most notably in the Fletcher condition (from 191.3 HV to 256.9 HV). These findings provide valuable insights into the time-dependent degradation mechanisms of orthodontic stainless steel in varied salivary environments, emphasizing the importance of simulating realistic oral conditions in corrosion testing. The study contributes to the optimization of material selection and surface treatment strategies for improved biocompatibility in dental applications. Full article

Jujube witches’ broom (JWB) disease, caused by Candidatus Phytoplasma ziziphi (Ca. P. ziziphi), severely threatens the production of Chinese jujube (Ziziphus jujuba Mill.). Emerging evidence highlights the critical role of phytoplasma-secreted effectors in pathogenesis, though few have been functionally characterized. Here, we identified a Sec-dependent effector, JWB790, from Ca. P. ziziphi, which was shown to suppress plant immunity. Through transient expression assays in Nicotiana benthamiana, pathogen inoculation assays, the generation of transgenic Arabidopsis thaliana plants, and RNA-seq-based transcriptomic profiling, we systematically investigated the virulence function of JWB790. Our findings revealed that JWB790 is highly expressed in JWB-infected tissues. The transient expression of JWB790 in N. benthamiana suppressed BAX-induced cell death and H₂O₂ accumulation. Furthermore, the stable overexpression of JWB790 in A. thaliana compromised disease resistance, accompanied by reduced H₂O₂ accumulation and callose deposition triggered by flg22. Additionally, the RNA-seq analysis of JWB790 transgenic Arabidopsis plants indicated that the overexpression of JWB790 altered the expression of biotic stress-related genes. In summary, JWB790 is a virulence factor that suppresses plant immunity and promotes pathogen proliferation. These results advance our understanding of Ca. P. ziziphi pathogenesis. Full article

Objectives: To evaluate how a 10-day multi-stressor field-training course—combining high physical and psycho-emotional demands, caloric restriction, and severe sleep deprivation—affects systemic oxidative/antioxidative status and biomarkers of nucleic-acid and skeletal-muscle damage in trained military cadets. Methods: Seventy-five healthy cadets (8 women, 67 men; 22–34 y) completed the course. Standardised operational rations (700–800 kcal day⁻¹) and two 20 min tactical naps per 24 h were enforced. Pre- and post-course venous blood was collected after an overnight fast. Plasma superoxide-dismutase activity (SOD), reduced and oxidised glutathione (GSH, GSSG), malondialdehyde (MDA), and hydrogen peroxide (H₂O₂) were quantified by colourimetric/fluorometric assays; 8-hydroxy-2-deoxyguanosine (8-OHdG) and myoglobin were measured by ELISA. The oxidative-stress index (OSI) was calculated as GSSG·GSH⁻¹. Within-subject differences were assessed with Wilcoxon signed-rank tests; associations between biomarker changes were explored by Spearman correlation. Results: After training, GSH (+175%, p < 0.001) and GSSG (+32%, p < 0.001) rose significantly, whereas SOD (−19%, p = 0.002), H₂O₂ (−20%, p = 0.015), MDA (−50%, p < 0.001), 8-OHdG (−23%, p < 0.001), and OSI (−47%, p < 0.001) declined. Myoglobin remained unchanged (p = 0.603). Reductions in MDA correlated inversely with increases in GSSG (rₛ = −0.25, p = 0.041), while H₂O₂ changes correlated positively with GSSG (rₛ = 0.25, p = 0.046), indicating a glutathione-driven adaptive response. Conclusions: Ten consecutive days of vigorous, calorie- and sleep-restricted field training elicited a favourable redox adaptation characterised by enhanced glutathione-mediated antioxidant capacity and lower circulating oxidant concentrations, without evidence of DNA or skeletal-muscle damage. The data suggest that, in physically prepared individuals, prolonged multi-stressor exposure can strengthen endogenous antioxidant defences rather than precipitate oxidative injury. Full article

This study presents the fabrication of a samarium-doped Ti/Sb-SnO₂/PbO₂ electrode and investigates its applications in polluted water treatment and energy conversion. Physicochemical properties were characterized by scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray powder diffraction analysis, and Raman spectroscopy. The Ti/Sb-SnO₂/Sm-PbO₂ electrode showed 2.5 times higher oxygen evolution potential activity than the Ti/Sb-SnO₂/PbO₂ electrode. Density Functional Theory was used to conduct first-principles calculations, and the obtained results indicated that Sm doping enhances the production of reactive oxygen species. The application of the Ti/Sb-SnO₂/Sm-PbO₂ electrode in carbendazim (CBZ) removal was investigated, since CBZ is a fungicide whose presence in the environment, including food, water, and soil, poses a threat. After 60 min of the treatment under optimized working parameters, the degradation rate of CBZ reached 94.2% in the presence of 7.2 g/L Na₂SO₄ with an applied current density of 10 mA/cm² in an acidic medium (pH 4). Of the four investigated parameters, the current density had the most significant influence on the degradation process. At the same time, the initial pH value of the solution was shown to have the least impact on degradation efficiency. These results imply a potential use of the proposed treatment for CBZ removal from wastewater. Full article

Para-coumaric acid (p-CA) is a phenolic compound that has antioxidant, anti-inflammatory, and anticancer properties which make it potential for cancer treatment. However, its effectiveness has been limited by poor solubility, rapid metabolism, and poor absorptivity. Nonthermal biocompatible pressure plasma (NBP) has gained attention as a cancer treatment due to its ability to generate reactive oxygen and nitrogen species (RONS), inducing oxidative stress that damages cancer cells. This study aimed to investigate the combined effect of NBP and p-CA on the induction of ferroptosis in lung adenocarcinoma via the GPX4, xCT, and NRF2 pathways. H460 and A549 lung adenocarcinoma cells as well as normal lung cells (MRC5) were treated with p-CA, NBP, and their combination. Cell movement, intracellular RONS levels, and lipid peroxidation, along with apoptosis and ferroptosis-related gene expression, were evaluated by co-treatment. Co-treatment also significantly elevated NO₂⁻, NO₃⁻, and H₂O₂ levels and reduced cancer cell (H460, A549) viability (26, 31%) without affecting normal cells MRC5 (7%). Elevated MDA levels and changed expression of ferroptotic proteins indicated mitochondrial dysfunction, oxidative damage, lipid peroxidation, and DNA damage, which resulted in the induction of ferroptosis. These findings reveal a novel ferroptosis mechanism, emphasizing co-treatment for delivering bioavailable natural anticancer drugs. Full article

The effect of ambient temperature on various physiological parameters were obtained to determine the upper critical temperature (UCT) in Iberian pigs. After an adaptation period at 28 °C, eight barrows (99 kg) were individually moved to two respirometry chambers and fed ad libitum (standard diet). The heat production (HP) and respiratory quotient (RQ) were measured over 24 h and some physiological parameters were measured every two days at 24, 26, 28, 30 and 32 °C. No differences (p > 0.05) were found in the heart rate (HR; 97.7 beats/min) and rectal temperature (RT; 39.7 °C) between ambient temperatures. Breathing rate (BR) and skin temperature (ST) increased (272 and 2.4%, respectively; p < 0.05) along with the temperature; whereas voluntary feed intake (VFI), retained energy (RE) and respiratory quotient (RQ) decreased (40.3, 65.8 and 10.5%, respectively; p < 0.001). Overall, HP slightly decreased (19.2%; p < 0.01) when the temperature increased. The reduction in RE when the temperature increased was related more to the decrease in VFI rather than to the concomitant reduction in HP. The UCT can be established at 28 for BR, 30 for VFI and RE, and 32 °C for ST, HP and RQ. Overall, the UCT was stablished at 28–30 °C, indicating the good adaptation of Iberian pigs to heat. Full article