Activities Of Key Enzymes Research Articles

Transcriptomics and metabonomics reveal molecular mechanisms promoting lipid production in Haematococcus pluvialis co-mutated by atmospheric and room temperature plasma with ethanol.

Atmospheric and room temperature plasma mutation and co-mutation with ethanol were employed to generate Haematococcus pluvialis mutants AV3 and AV8. These mutants were screened using multiple indices of chlorophyll fluorescence, quantum yield, lethality, growth rate, dry cell weight, and lipid content. Compared to the wild strain, the mutants demonstrated genetic stability (*p>0.05) over three cultivation periods, with biomass, lipid content, and growth rate increasing by over 16%, 55%, and 45%, respectively. Lipid accumulation was correlated with higher activities of key lipid biosynthesis enzymes, acetyl-CoA carboxylase, and diacylglycerol acyltransferases. Transcriptomic and metabolomic analyses revealed differentially expressed genes and differential metabolites, with significant changes in glutathione, arginine and Pyruvate metabolism pathways. This study provides new insights into the molecular mechanisms behind enhanced lipid synthesis and highlights the potential of plasma mutation for improving lipid production in microalgae, offering a promising avenue for biofuel production.

Effect of Exogenous IBA on Root Morphology and Endogenous Hormone Metabolic Pathways in Castor Seedlings Under Pb/Zn Stress

Ricinus communis, a plant of significant industrial value for its oil, is renowned for its robust root system and vigorous growth, qualities that render it an exemplary candidate for the ecological remediation of soils contaminated with heavy metals. The impact of heavy metal stress on root development is characterized by inhibition, a phenomenon whose underlying mechanisms are not fully elucidated. To shed light on this, a study was conducted wherein varying concentrations of the exogenous auxin, IBA, were applied to the roots of Ricinus communis to scrutinize its influence on the endogenous indole-3-acetic acid (IAA) metabolism in seedlings and to delineate the molecular underpinnings of its effects on root morphology. It was observed that IBA significantly amplified the total root surface area by a factor of 1.29 and increased the number of root tips by 40.11% under lead (Pb) stress, and by 32.29% and 91.19%, respectively, under zinc (Zn) stress. These findings underscore the efficacy of IBA in promoting the proliferation of lateral roots in seedlings subjected to stress induced by either Pb or Zn. Further analysis of auxin signaling pathways revealed that the presence of Pb or Zn impedes root growth and lateral root formation by perturbing auxin transporters and signaling molecules. Notably, IBA was found to foster the development of lateral roots by modulating the expression of specific transporters. Post-application of IBA, the endogenous levels of IAA in roots exhibited a 2.80-fold elevation under Pb stress, IBA stimulated the activity of key biosynthetic enzymes, such as RcNIT and RcTAR, culminating in elevated IAA levels. Conversely, under Zn stress, IBA was observed to diminish the levels of RcTAR, which in turn led to reduced IAA levels. These outcomes contribute to a deeper comprehension of the modulatory role of IBA in the context of heavy metal stress.

Role of syringic acid in enhancing growth, photosynthesis, and antioxidant defense in lettuce exposed to arsenic stress.

Heavy metal pollution, especially arsenic toxicity, significantly impairs plant growth and development. Phenolic acids, known for their antioxidant properties and involvement in stress signaling, are gaining increased attention as plant secondary metabolites with the potential to enhance plant resistance to these stressors. This study aimed to investigate the effects of different concentrations of syringic acid (SA1, 10 μM; SA2, 250 μM; SA3, 500 μM) on growth, photosynthetic parameters, and antioxidant activity in lettuce seedlings subjected to arsenic stress (As, 100 μM). Arsenic stress reduced growth by 56.7%, water content by 7.39%, and osmotic potential by 26.2% in lettuce leaves compared to control. Conversely, SA1 and SA2 treatments mitigated the adverse effects of arsenic on growth and preserved the water balance in plants. However, the SA3 treatment led to a decrease in growth by 18.9% and 39.5% in the SA3 and As+SA3 groups, respectively, indicating that high-dose SA treatment adversely affected lettuce leaves under both control and stress conditions. Exogenous SA1 treatment significantly improved photosynthesis, whereas SA2 provided milder benefits and SA3 did not reduce the adverse effects of arsenic exposure. Arsenic stress increased H2O2 content by 47.3% and lipid peroxidation by 33.4% in lettuce seedlings. SA1 treatment effectively reduced oxidative stress by enhancing the activities of key antioxidant enzymes, such as superoxide dismutase (SOD) and peroxidase (POX). Moreover, SA1 was successful in maintaining the glutathione (GSH) pool, whereas SA2 primarily promoted ascorbate (AsA) regeneration. In conclusion, 10 μM of syringic acid (SA1) was identified as the optimal dose for reducing arsenic stress in lettuce by enhancing antioxidant activity and supporting growth. Overall, the findings underscore the potential of SA1 treatment in enhancing the resilience of lettuce to heavy metal toxicity.

Novel ZnO-TiO2@MSC nanomaterial based on corn stover template enhances disease resistance in tomato plants.

Crop diseases significantly threaten global food security, driving the need for innovative control strategies. This study explored using ZnO-TiO2@MSC, a novel nanomaterial synthesized using a corn stover template, to enhance disease resistance in tomato plants. In vitro assays demonstrated potent antimicrobial activity of ZnO-TiO2@MSC against the pathogen Pseudomonas syringae pv. tomato DC3000 (Pst. DC3000) by disrupting bacterial cell membranes and modulating oxidative stress-related gene expression. When applied to tomato leaves in pot trials, ZnO-TiO2@MSC achieved 79.83% control of bacterial leaf spot disease while promoting plant growth and photosynthesis. The nanomaterial triggered plant defense mechanisms, upregulating resistance genes and increasing the activities of key enzymes. Metabolomic profiling revealed elevated lipids, lipid-like molecules, and organic acid derivative levels in treated leaves, suggesting cell membrane remodeling as part of the defense response. These findings highlight the potential of biologically-templated nanomaterials like ZnO-TiO2@MSC as multifunctional tools for sustainable disease management in crops. The corn stover-based synthesis approach also provides a way to valorize agricultural waste. Further research is needed to understand the long-term impacts and viability of field-scale application of ZnO-TiO2@MSC as an alternative to conventional pesticides.

Simultaneous degradation of roxithromycin and nitrogen removal by Acinetobacter pittii TR1: Performances, pathways, and mechanisms.

Pharmaceutical and aquaculture wastewater contains not only antibiotics but also high concentrations of nitrogen, but few studies have been conducted on bacteria that target this complex pollution for degradation. A novel heterotrophic nitrifying aerobic denitrifying (HN-AD) strain Acinetobacter pittii TR1 isolated from soil. When the C/N ratio was 20, the strain could degrade 50mg/L roxithromycin (ROX) and the nitrogen removal rate was 96.06% with no accumulation of nitrite. The nitrogen metabolism pathway of strain TR1 was conjectured by NH4+-N → (NH2OH) → NO2--N → NO3--N → NO2--N → (NO → N2O → N2). Nitrogen balance analysis showed that 50.43% of the initial total nitrogen (TN) was converted to gaseous nitrogen and 45.39% was assimilated by TR1. Lower concentrations of ROX affected the activity of key enzymes, and the expression of the denitrifying genes hao, napA, nirK, norZ, and nosZ were significantly up-regulated, with the gene expression of nirK being up-regulated by 15.9-fold. Cleavage of desosamine, demethylation, and phosphorylation were the main biotransformation pathways of ROX. This work offers fresh insights into the metabolic processes of HN-AD bacteria under antibiotic stress, as well as evidence supporting strain TR1 in the treatment of wastewater with nitrogen and ROX.

Leveraging Metabolomics and Ionomics to Illuminate Aluminum-Induced Toxicity in Mouse Organs

Aluminum, a widely prevalent environmental pollutant, has been established to exert toxic effects on multiple organs in the human body. To gain a comprehensive understanding of these toxic effects and the mechanisms involved, this study aimed to assess potential correlations between metabolites and ion data through metabolomic and ionomic analyses. We sought to explore the intricate impact of aluminum on various organs in mice. Gas chromatography-mass spectrometry (GC-MS) and inductively coupled plasma-mass spectrometry (ICP-MS) were employed to conduct metabolomic and ionomic analyses on the hippocampus, cortex, heart, liver, spleen, lung, kidney, bone, intestine, stomach, and serum of both control and aluminum-exposed mice. Besides, histological examinations and behavioral experiments were conducted. Multivariate analysis revealed 91 differential metabolites across various organs, primarily encompassing amino acids, fatty acids, and carbohydrates. The implicated abnormal metabolic pathways included amino acid metabolism, arachidonic acid metabolism, and glutathione metabolism. Additionally, alterations in the homeostasis of ions such as manganese, zinc, selenium, iron, copper, phosphorus, magnesium, and calcium were observed in various organs, potentially influencing the activity of critical enzymes. The changes in these potential biomarkers and ions suggest toxic mechanisms of aluminum exposure involving oxidative stress, inflammatory responses, cellular signal dysregulation, disruption of key enzyme activities, and impaired energy metabolism. This study provides a novel perspective on understanding the toxic mechanisms of aluminum exposure, potentially contributing to the prevention and treatment of aluminum toxicity.

Boron's Role in Diminishing Cadmium Concentrations in Rice (Oryza sativa L.): Insights into Absorption Inhibition and Ripening Promotion.

Boron, a crucial element for plant growth, has been demonstrated to mitigate cadmium (Cd) absorption in rice seedlings. However, its impact on Cd accumulation in rice grains and the underlying regulatory mechanisms remain poorly understood. The current study explored the roles of boron in reducing Cd accumulation and promoting ripening in rice through pot and hydroponic experiments. The results revealed that the basal boron application (1.5 mg kg-1) decreased grain Cd concentration by 61.1%, primarily due to the synergistic effects of inhibited Cd uptake and transport, along with increased maturation. Boron mitigated the root Cd2+ influx by 32.4% and transport factors by 36.0-47.3% primarily by downregulating the expression of OsNramp5, OsIRT1, and OsHMA2. Moreover, boron enhanced the activities of key sucrose-metabolizing enzymes and increased the relative expression levels of genes associated with sugar metabolism and transport, thereby shortening the rice growth period from 132 to 120 d. Field experiment confirmed that boron application decreased rice grain Cd concentration by 47.7% while promoting earlier maturation. This study elucidates the mechanism behind boron's ability to lower grain Cd levels and highlights its potential as an effective agronomic approach to mitigate food safety risks in rice grown on Cd-contaminated paddy soils.

Augmented carbon utilization and ammonia assimilation in heterotrophic microorganism under magnetic field stimulation.

Ammonia assimilation is crucial in microbial nitrogen metabolism, and researching the impact of magnetic field (MF) on heterotrophic ammonia assimilation (HAA) contributes to improving nitrogen utilization and environmental remediation. This study systematically investigated the profound effects of MF stimulation on carbon and ammonia assimilation mechanisms in heterotrophic microorganisms. The dynamic responses of microbial carbon source metabolic efficiency and nitrogen source assimilation rates were quantitatively analyzed by designing a multidimensional stimulation environment of different nutrient levels (C/N 20, 25, 30) and MF intensities (0, 1, 20 mT). The findings demonstrated that weak MF stimulation markedly enhanced carbon utilization efficiency and ammonia assimilation capacity, evidenced by accelerated metabolic flux, significant biomass augmentation and metabolic network reconfiguration. MF induced pronounced activation of key metabolic enzymes, uncovering coordinated regulatory mechanisms at the molecular level. Additionally, the MF stimulation enriched genera the Halomonas and Marinobacter, enhancing the stability of microbial community. These discoveries not only advance the theoretical understanding of MF-enhanced metabolic modulation but also offer cutting-edge insights and potential solutions for developing MF-assisted bioconversion and environmental remediation technologies.

Digestive and metabolic profile of the resident population of the silverside Odontesthes argentinensis from Mar Chiquita Coastal Lagoon (Buenos Aires, Argentina).

The knowledge about the occurrence and biochemical characteristics of key digestive enzymes is crucial for an enhanced understanding of the dietary ecophysiology of the species. On the other hand, integrative studies on digestive physiology and on tissue content of glycogen, glucose, lipid and protein in groups of ecological and economic importance are currently limited. In this work, we determined the occurrence and biochemical characteristics in intestine of key digestive enzymes activities as indexes of the ability to digest different dietary substrates and of functional differentiation for digestion/absorption of nutrients along with the intestinal coefficient as index of dietary habit and digestion efficiency in adults of Odonthtestes argentinensis inhabiting Mar Chiquita Coastal Lagoon (Buenos Aires, Argentina). Furthermore, to identify storage sites, glycogen, triglycerides and protein content in different tissues were also analyzed. The presence and biochemical characteristics of amylase, maltase, sucrase, lipase, trypsin and aminopeptidase-N activity in intestine, as well as the tissue content of glycogen, triglycerides and protein suggests that adults of O.argentinensis exhibit an adequate digestive battery to potentially perform complete hydrolysis of various dietary substrates and capacity for storage and/or utilization of energy reserves. Our study provides novel insights into the digestive/metabolic traits in adults of the resident silverside O. argentinensis from Mar Chiquita Coastal Lagoon.

Impact of zinc supplementation on cellular and molecular biomechanical alterations and critical outcomes in pediatric patients with sepsis: A randomized controlled trial

Background: Sepsis remains a significant contributor to illness and death in children. Studies suggests that potential benefits of zinc supplementation in patients with sepsis, such as reduced inflammation and mortality rates. Zinc is involved in maintaining the structural integrity and function of cell membranes, which is essential for proper cell signaling and biomechanical responses. It can also influence the activity of key enzymes and proteins that regulate intracellular and extracellular forces, thereby affecting cell adhesion, migration, and overall tissue mechanics. Therefore, this study aimed to evaluate the occurrence of Acute Respiratory Distress Syndrome (ARDS), Septic Shock, Acute Kidney Injury (AKI), and Mortality in Pediatric Sepsis receiving Zinc supplementation, with a focus on the underlying cellular and molecular biomechanical mechanisms. Methods: This study was a Randomized Control Trial (RCT) conducted using a parallel-group, double-blind design and prospective cohort approach. Participants were selected through consecutive sampling and then randomized into two groups: one receiving standard therapy plus zinc supplementation and the other receiving standard therapy plus a placebo. Results: Among pediatric patients with sepsis, the incidence of septic shock was significantly lower in the group receiving standard therapy with zinc supplementation (34.4%) compared to the placebo group (65.6%) (p = 0.00, OR 2.29, 95% CI: 1.28–4.11). The incidence of ARDS was 66.7% in the placebo group, versus 33.3% in the zinc group (p = 0.00, OR 0.37, 95% CI: 0.22–0.64). For acute kidney injury (AKI), 65.7% occurred in the placebo group compared to 34.3% in the zinc group (p = 0.04, OR 2.09, 95% CI: 0.99–4.40). Mortality in the placebo group was 64.3%, while in the zinc group it was 35.7% (p = 0.01, OR 0.48, 95% CI: 0.26–0.88). Conclusion: Zinc supplementation significantly reduces the incidence of acute respiratory distress syndrome, acute kidney injury, septic shock, and mortality in pediatric patients with sepsis. These outcomes may be attributed to zinc’s role in modulating cellular signaling pathways, enhancing cellular integrity under stress, and improving the biomechanical properties of cell membranes, thereby promoting better physiological responses in the context of sepsis.

Carbon Dioxide Micro-Nano Bubbles Aeration Improves Carbon Fixation Efficiency for Succinic Acid Synthesis by Escherichia coli

The low solubility of CO2 in water leads to massive CO2 emission and extremely low CO2 utilization in succinic acid (SA) biosynthesis. To enhance microbial CO2 utilization, micro-nano bubbles (MNBs) were induced in SA biosynthesis by E. coli Suc260 in this study. The results showed that MNB aeration decreased CO2 emissions and increased CO2 solubility in the medium significantly. The CO2 utilization of MNB aeration was 129.69% higher than that of bubble aeration in atmospheric fermentation. However, MNBs showed a significant inhibitory effect on bacterial growth in the pressurized environment, although a two-stage aerobic–anaerobic fermentation strategy weakened the inhibition. The biofilm-enhanced strain E. coli Suc260-CsgA showed a strong tolerance to MNBs. In pressurized fermentation with MNB aeration, the actual CO2 utilization of E. coli Suc260-CsgA was 30.63% at 0.18 MPa, which was a 6.49-times improvement. The CO2 requirement for SA synthesis decreased by 83.4%, and the fugitive emission of CO2 was successfully controlled. The activities of key enzymes within the SA synthesis pathway were also maintained or enhanced in the fermentation process with MNB aeration. These results indicated that the biofilm-enhanced strain and CO2-MNBs could improve carbon fixation efficiency in microbial carbon sequestration.

Resveratrol mitigates heat stress-induced testicular injury in rats: enhancing male fertility via antioxidant, antiapoptotic, pro-proliferative, and anti-inflammatory mechanisms.

This study investigates the protective effects of resveratrol (RSV) against heat stress (HS)-induced testicular injury in rats. Climate change has exacerbated heat stress, particularly affecting male fertility by impairing testicular function and sexual behavior. A total of 32 rats were allocated into four experimental groups: control, RSV control, HS control, and RSV + HS. The HS groups were subjected to a 43°C water bath for 20 min to induce testicular hyperthermia, while the RSV + HS group received 20 mg/kg of RSV starting just before HS and continuing for eight weeks. Our findings reveal that HS significantly impairs male sexual behavior, evidenced by reduced mount and intromission numbers, and increased latencies. It also negatively affects the reproductive system, decreasing the weights of testes (Cohen's d = 1.8), epididymis, and accessory sex glands, and deteriorating sperm profile parameters such as motility (Cohen's d = 2.1), viability, and morphology. Furthermore, HS notably decreases reproductive performance in female rats, reducing litter size, live births, and conception rates. Biochemically, HS decreases activities of key antioxidant enzymes in the testes-glutathione peroxidase, superoxide dismutase, and catalase-while increasing lipid peroxidation, nitrite levels, and proinflammatory cytokines (IL-1β and TNF-α). It also reduces serum levels of reproductive hormones like testosterone (Cohen's d = 2.0) and 17β-estradiol.These results were affirmed with the histopathological evaluation and the immunohistochemistry staining (Ki-67, PCNA, Bax 5, and caspase-3 protein expression). Remarkably, RSV treatment mitigated these adverse effects, restoring both physiological and biochemical parameters toward normal levels (e.g., testicular weight Cohen's d = 1.6, sperm motility Cohen's d = 1.9, and testosterone levels Cohen's d = 1.7). This suggests that RSV's antioxidative, anti-inflammatory, antiapoptotic, and androgenic properties could effectively counteract the degenerative impacts of testicular hyperthermia. This highlights the potential of RSV as a therapeutic agent against climate change-induced fertility issues in males.

Abnormalities in mitochondrial energy metabolism induced by cryopreservation negatively affect goat sperm motility.

The motility of sperm decreases following cryopreservation, which is closely associated with mitochondrial function. However, the alterations in mitochondrial metabolism after sperm freezing in goats remain unclear. This experiment aimed to investigate the impact of ultra-low temperature freezing on goat sperm's mitochondrial energy metabolism and its potential correlation with sperm motility. The results revealed that goat sperm exhibited mitochondrial vacuolization, reduced matrix density, and significantly decreased levels of high-membrane potential mitochondria and adenosine triphosphate content, accompanied by a substantial increase in reactive oxygen species levels, ultimately leading to a significant decline in sperm viability. Further investigations unveiled that energy-related differential metabolites (capric acid, creatine, and D-glucosamine-6-phosphate) and differential metabolites with antioxidant effects (saikosaponin A, probucol, and cholesterol sulfate) were significantly downregulated. In addition, the activity of key rate-limiting enzymes involved in very long-chain fatty acid biosynthesis and β-oxidation-specifically acetyl-CoA carboxylase, fatty acid synthase, and carnitine palmitoyltransferase I related to capric acid metabolism-was considerably reduced. Furthermore, supplementation of differential metabolite capric acid (500 μM) significantly enhanced the motility of frozen-thawed goat sperm. These findings indicated that the mitochondrial ultrastructure of goat sperm is damaged and energy metabolism becomes abnormal after cryopreservation, potentially affecting sperm viability. The addition of different metabolites such as capric acid to the freezing extender can alleviate the decrease in sperm motility induced by cryopreservation.

Emerging Roles of Dermal Fibroblasts in Hyperpigmentation and Hypopigmentation: A Review.

Skin pigmentation disorders may increase patients' psychological burdens. Consequently, they are increasingly attracting attention. Dermal fibroblasts have been shown to regulate pigmentation by secreting soluble factors. This study aimed to summarize recent findings on the effects of dermal fibroblasts on hyperpigmentation and hypopigmentation, enabling the discovery of new therapeutic targets. PubMed was searched for literature on fibroblast factors, hyperpigmentation, and hypopigmentation, and a comprehensive summary and analysis were performed. Fibroblasts secrete both cytokines that promote pigmentation, including stem cell factor (SCF) and keratinocyte growth factor (KGF), and small amounts of those that inhibit pigmentation, such as Dickkopf1 (DKK1) and transforming growth factor (TGF)-β. Fibroblast-derived extracellular matrix (ECM) can also affect melanocyte tyrosinase activity and the transfer of melanosomes. In hyperpigmentation disorders, such as melasma and solar lentigines, the secretion of pigmentation-promoting factors increases, and the activity of key enzymes in melanin production is elevated. In hypopigmentation disorders, including vitiligo, the secretion of melanogenic factors decreases while the factors that inhibit pigmentation increase. Fibroblasts may serve as a new therapeutic target, providing new insights to precisely treat pigmentary disorders. Fibroblasts synthesize and secrete various cytokines and proteins that modify melanin synthesis and transfer through different signaling pathways, playing prominent roles in pigmentary skin disorders, such as photoaging, melasma, solar lentigo, and vitiligo.

Study on the mechanism of regulating micromolar Fe utilization and promoting denitrification by guanosine monophosphate (GMP) based multi-signal functional material Hematin@Fe/GMP

A novel multi-signal functional material consisting of Hematin, Fe, and guanosine monophosphate (GMP) was successfully constructed (Hematin@Fe/GMP) to enhance denitrification efficiency based on the signal network regulation of electron transfer, micromolar Fe utilization, and microbial community. Hematin@Fe/GMP enhanced nitrate reduction rate by 2.33-fold with a 9.9 mg L-1 h-1 reduction rate. The mechanisms of accelerated denitrification were elaborated deeply from the electrochemical experiments, microbial metabolism activity, key enzyme activity, gene expression, and microbial community. Specifically, electrochemical experiments and X-ray photoelectron spectroscopy demonstrated that the released redox signal (Fe2+/Fe3+) promoted the increased redox substances (extracellular polymeric substances, cytochrome c, and riboflavin) to accelerate electron transfer efficiency. Metagenomic analysis suggested the released Fe utilization signal modulated siderophores genes (fhuB, fhuC, and fhuD) to promote the uptake and utilization of micromolar Fe, which was more conducive to synthesizing cytochrome c. Moreover, extracellular polymeric substances (EPS) stripping experiments demonstrated that the membrane-anchored cyt-c could shuttle in EPS and bind with Hematin@Fe/GMP to form an electrical conduit for accelerating denitrification efficiency. In inhibition experiments, Hematin@Fe/GMP could break down electron transfer barriers and restore/compensate for the electron transfer chain. Meanwhile, Hematin@Fe/GMP could restore the electrical signal disruption and synergize with the enriched signaling-capable microorganisms (Stutzerimonas and Thauera) to regulate quorum sensing. This research introduced multi-signal modulation of Hematin@Fe/GMP on denitrification and provided strategies for accelerating the biological transformation process and effectively utilizing micromolar Fe in practical applications.

Key enzymatic activities and metabolic pathway dynamics in acidogenic fermentation of food waste: Impact of pH and organic loading rate.

Acidogenic fermentation was an effective technology to recover volatile fatty acids (VFAs) ethanol and lactic acid from food wastes (FW) as bioresources. However, the impact of process controls on key functional enzymes and metabolic pathways has been inadequately understood. In this study, the metabolite distribution, key functional enzymes and metabolic pathways were completely elucidated using 16S rRNA gene high-throughput sequencing combined with PICRUSt2. Results demonstrated pH significantly affected fermentation types by influencing key enzyme activities, while organic loading rate (OLR) primarily affected the yield without altering metabolic pathway. The maximum VFAs production was achieved at pH 6.0 and OLR of 15.0g-VS/L/d as a result of Glycolysis and Pyruvate Metabolism were enhanced. Meanwhile, butyric acid was always dominant product, attributed to the enhanced activity of butyryl-CoA dehydrogenasedue. Furthermore, Lactobacillus enrichment and lactate dehydrogenase upregulation promoted lactate-type fermentation under without pH control (3.8), resulting in an average yield of lactic acid was 7.84g/L. When the pH was raised from 3.8 to 5.0,downregulation of lactate dehydrogenase and upregulation of acetate kinase shifted the fermentation to acetate-type. This study provides a deeper understanding of how does process controls influence the metabolic pathways and key functional enzymes.

Extracellular enzymes as reliable indicators of long-term antimony contamination.

Antimony (Sb) contamination in soil has become a growing concern due to its toxic effects on ecological soil functions. Soil enzymes, which are effective biological indicators, play a crucial role in assessing the ecological impact of heavy metals in soil. However, the effects of Sb on soil enzyme activity, particularly during the ageing process, remain poorly understood. This study examines the ageing process of Sb in soil and its biological toxicity on three key soil enzyme activities (arylsulfatase, urease, phosphatase) at different enzyme pool levels (total, intracellular and extracellular). Our findings reveal that the ageing of exogenous Sb in soil follows a heterogeneous dispersion process, with the Sb ageing rate constant (|b|) in acidic soil (S1, red soil, pH4.90) being 1.21 to 1.90 times higher than in alkaline soil (S2, gray desert soil, pH8.12). This suggests that Sb stabilizes more rapidly in acidic conditions. Regarding Sb effects on soil enzymes, extracellular urease activity and the total enzyme activity index (TEI) of extracellular enzymes were particularly sensitive to Sb stress. Over the course of the ageing period, extracellular urease activity decreased by 23.46-57.85% in both soils under Sb stress at 7000mg·kg-1. The inhibition of TEI by Sb ranged from 29.08 to 42.47% in S1 soil, and from 12.47 to 20.65% in S2 soil. Ecological dose (ED10) values indicated that Sb concentrations of 24.86-184.00mg·kg-1 caused a 10% reduction in extracellular enzyme TEI, whereas higher Sb concentrations (29.63-1791.86mg·kg-1) were needed to inhibit 10% of extracellular urease activity. Overall, TEI of extracellular enzymes emerges as a more sensitive and reliable indicator of long-term Sb contamination. This study provides essential insights for monitoring Sb pollution and provides a basis for establishing a soil Sb pollution assessment and early-warning system.

The Nitrogen Fixation Characteristics of Terrestrial Nitrogen-Fixing Cyanobacteria and Their Role in Promoting Rice Growth

Cyanobacteria, ubiquitous phototrophic prokaryotes, can enhance soil fertility and crop productivity by promoting biological nitrogen fixation, phosphate dissolution, and mineral release. In this study, five nitrogen-fixing cyanobacteria were isolated and purified from paddy soil in Jilin Province. The effects of nitrogen-fixing cyanobacteria on soil fertility and rice seedling growth were examined through a pot experiment to clarify their growth and nitrogen-fixing characteristics. The results showed that the application of nitrogen-fixing cyanobacteria led to a significant increase in soil nitrogen content. GD2 and GD8 have the highest nitrogenase activity, at 75.33 U·mg−1 and 50.34 U·mg−1, respectively. It also enhanced the activities of urease, sucrase, phosphatase, and catalase in rice soil. In addition, it significantly promoted root development and plant height in rice plants. The total number of microorganisms in rice soil increased by 133–366%. Remarkably, the Desmonostoc muscorum GD2 strain was found to exhibit higher growth state indicators, including the growth curve, chlorophyll content, carbon and nitrogen content, and biomass accumulation, compared to other algae strains. The total nitrogen content of rice leaves treated with GD2 increased by 48.73%, and the soluble protein content increased by 52.89%. GD2 has great potential as an excellent nitrogen-fixing cyanobacteria inoculant for rice, suitable for agricultural production. In conclusion, the application of these nitrogen-fixing cyanobacteria significantly increased soil nitrogen levels and activated key enzyme activities involved in plant nitrogen metabolism. Moreover, it improved nitrogen utilization rates and promoted plant growth.

Epigenetic Properties of Compounds Contained in Functional Foods Against Cancer.

Epigenetics encompasses reversible and heritable genomic changes in histones, DNA expression, and non-coding RNAs that occur without modifying the nucleotide DNA sequence. These changes play a critical role in modulating cell function in both healthy and pathological conditions. Dysregulated epigenetic mechanisms are implicated in various diseases, including cardiovascular disorders, neurodegenerative diseases, obesity, and mainly cancer. Therefore, to develop innovative therapeutic strategies, research for compounds able to modulate the complex epigenetic landscape of cancer is rapidly surging. Dietary phytochemicals, mostly flavonoids but also tetraterpenoids, organosulfur compounds, and isothiocyanates, represent biologically active molecules found in vegetables, fruits, medicinal plants, and beverages. These natural organic compounds exhibit epigenetic modulatory properties by influencing the activity of epigenetics key enzymes, such as DNA methyltransferases, histone acetyltransferases and deacetylases, and histone methyltransferases and demethylases. Due to the reversibility of the modifications that they induce, their minimal adverse effects, and their potent epigenetic regulatory activity, dietary phytochemicals hold significant promise as antitumor agents and warrant further investigation. This review aims to consolidate current data on the diverse epigenetic effects of the six major flavonoid subclasses, as well as other natural compounds, in the context of cancer. The goal is to identify new therapeutic epigenetic targets for drug development, whether as stand-alone treatments or in combination with conventional antitumor approaches.

Phytic Acid Delays the Senescence of Rosa roxburghii Fruit by Regulating Antioxidant Capacity and the Ascorbate-Glutathione Cycle.

Rosa roxburghii fruit has a short postharvest shelf life, with rapid declines in quality and antioxidant capacity. This research assessed how phytic acid affects the antioxidant capacity and quality of R. roxburghii fruit while in the postharvest storage period and reveals its potential mechanism of action. The findings suggested that phytic acid treatment inhibits the production of malondialdehyde (MDA) and enhances the activities and expressions of glutathione peroxidase (GPX), peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) while decreasing the generation of superoxide anions (O2•-) and hydrogen peroxide (H2O2). Phytic acid treatment activates the ascorbate-glutathione (AsA-GSH) cycle and enhances the activity and expression of key enzymes in the cycle: ascorbate peroxidase (APX), glutathione reductase (GR), dehydroascorbate reductase (DHAR), and monodehydroascorbate reductase (MDHAR). It also increases the levels of non-enzymatic antioxidants, such as ascorbic acid (AsA) and glutathione (GSH), while reducing the production of dehydroascorbic acid (DHA) and oxidized glutathione (GSSG). Moreover, phytic acid treatment enhances the ratios of AsA/DHA and GSH/GSSG, maintaining the reduced state of the fruit. In summary, phytic acid improves antioxidant defense system and activates the AsA-GSH cycle, alleviating oxidative damage and ensuring R. roxburghii fruit quality after harvest.