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Food Chemistry Jan 2024Sensitive detection strategies for enzymes and their inhibitors not only have critical significance in clinical diagnosis but can be extended to food and environment...
In situ formation of fluorescence species for the detection of alkaline phosphatase and organophosphorus pesticide via the ascorbate oxidase mimetic activity of AgPd bimetallic nanoflowers.
Sensitive detection strategies for enzymes and their inhibitors not only have critical significance in clinical diagnosis but can be extended to food and environment analysis. Here, bimetallic AgPd alloy nanoflowers were synthesized using carbon dots as the reductant via a two-step reduction method. The AgPd bimetallic nanoflowers exhibit ascorbate oxidase mimetic activity, which can rapidly catalyze the oxidization of ascorbic acid to dehydroascorbic acid (DHA). The DHA can then react with o-phenylenediamine (OPD) to produce 3-(1, 2-dihydroxyethyl)furo[3,4-b] quinoxalin-1(3H)-one (DFQ), accompanying with the characteristic fluorescence peak at 440 nm for DFQ. Alkaline phosphatase catalyzes l-ascorbyl-2-phosphate to generate AA, while organic phosphorus pesticides (OPPs) such as chlorpyrifos can inhibit the activity of alkaline phosphatase. By utilizing the enzyme-nanozyme tandem catalytic reaction, the fluorescence of the system varies in the presence of different concentrations of ALP or OPPs, which can be used to detect ALP in serum and OPPs in vegetables and fruits.
Topics: Alkaline Phosphatase; Ascorbate Oxidase; Organophosphorus Compounds; Pesticides; Fluorescent Dyes; Limit of Detection
PubMed: 37542966
DOI: 10.1016/j.foodchem.2023.137062 -
Frontiers in Microbiology 2023The production of pyocyanin by increases its virulence, fitness and biofilm formation. Pyocyanin is also a redox molecule and we hypothesize that ascorbic acid being an...
The production of pyocyanin by increases its virulence, fitness and biofilm formation. Pyocyanin is also a redox molecule and we hypothesize that ascorbic acid being an antioxidant will interact with pyocyanin. The main objective of this study was to investigate the potential interaction of ascorbic acid with pyocyanin, and also to investigate the impact of ascorbic acid in combination with Furanone-30 on quorum sensing and biofilm formation of . When incubated with ascorbic acid, hyperchromic and hypsochromic shifts in pyocyanin absorbance peaks at 385 nm and 695 nm were observed. In the presence of dehydroascorbic acid and citric acid, these shifts were absent, indicating that the intrinsic antioxidant property of ascorbic acid was probably essential in binding to pyocyanin. NMR spectroscopy showed shifts in H NMR pyocyanin peaks between 8.2 to 5.8 ppm when incubated in the presence of ascorbic acid. Density Functional Theory (DFT) supported potential interactions between the -CHOH or -OH moieties of ascorbic acid with the -C=O moiety of pyocyanin. The pyocyanin-ascorbic acid complex impaired pyocyanin binding to DNA. Ascorbic acid combined with furanone-30 elevated quorum-sensing inhibition in , which was directly associated with significantly reduced virulence, adhesion, aggregation and biofilm formation and enhanced antibiotic-mediated bacterial killing. This study demonstrated that the antioxidant ascorbic acid directly binds to pyocyanin, modulates its structure and results in disruption of biofilm formation and associated tolerance to antibiotics.
PubMed: 37520362
DOI: 10.3389/fmicb.2023.1166607 -
Ecotoxicology and Environmental Safety Sep 2023As a gas signal molecule, hydrogen sulfide (HS) can participate in many physiological and biochemical processes such as seed germination and photosynthesis regulation....
As a gas signal molecule, hydrogen sulfide (HS) can participate in many physiological and biochemical processes such as seed germination and photosynthesis regulation. In order to explore the regulatory effect of HS on the growth of Miscanthus sacchariflorus under Cd stress and to provide sufficient theoretical basis for the complex action of HS and energy plants to remediate soil pollution. In this experiment, the effects of different concentrations of HS (10, 25, 50, 100, 300, 400, 500 μmol·L (μM)) pretreatment on the growth index, lipid peroxidation degree, chlorophyll (Chl) content, osmoregulation substance content, antioxidant enzyme activity and non-enzymatic antioxidant content of M. sacchariflorus under Cd stress (50 μM) were studied. The results showed that under Cd stress, the reactive oxygen species (ROS) content in the body of M. sacchariflorus was unbalanced, and the growth were severely inhibited, the activities of antioxidant enzymes, such as catalase (CAT) and superoxide dismutase (SOD) significantly decreased, and the content of osmoregulation substance, ascorbic acid (AsA) and glutathione (GSH) significantly increased. With the increase of HS concentration, its effect on resisting Cd stress can be shown as "low concentration promotes, high concentration inhibits". When the concentration of HS ≤ 300 μM, although there was no significant difference in Cd content compared with Cd treatment alone, it can regulate the activities of peroxidase (POD), SOD, glutathione reductase (GR) and monodehydroascorbate reductase (MDHAR), increase the content of osmoregulation substances, oxidized glutathione (GSSG), and the transformation rate of AsA and dehydroascorbic acid (DHA) to reduce the oxidative damage and improve the growth and photosynthetic indicators of plants; when the concentration of HS ≥ 400 μM, Cd content in the ground and root decreased significantly, but the transport factor increased significantly, the growth status of M. sacchariflorus were more severely inhibited by the combined stress of HS and Cd. In this experiment, it was found that the concentration of HS pretreatment ≤ 300 μM could regulate the growth of M. sacchariflorus under Cd stress to normal level, and when the treatment concentration was 50 μM, the effect was the best. It will provide a new idea for the treatment of contaminated soil by energy plants.
Topics: Antioxidants; Cadmium; Seedlings; Hydrogen Sulfide; Ascorbic Acid; Glutathione; Oxidative Stress; Superoxide Dismutase; Poaceae; Hydrogen Peroxide
PubMed: 37499387
DOI: 10.1016/j.ecoenv.2023.115281 -
Frontiers in Neuroscience 2023Different studies have established the fundamental role of vitamin C in proliferation, differentiation, and neurogenesis in embryonic and adult brains, as well as in... (Review)
Review
Different studies have established the fundamental role of vitamin C in proliferation, differentiation, and neurogenesis in embryonic and adult brains, as well as in cell models. To fulfill these functions, the cells of the nervous system regulate the expression and sorting of sodium-dependent vitamin C transporter 2 (SVCT2), as well as the recycling of vitamin C between ascorbic acid (AA) and dehydroascorbic acid (DHA) via a bystander effect. SVCT2 is a transporter preferentially expressed in neurons and in neural precursor cells. In developmental stages, it is concentrated in the apical region of the radial glia, and in adult life, it is expressed preferentially in motor neurons of the cerebral cortex, starting on postnatal day 1. In neurogenic niches, SVCT2 is preferentially expressed in precursors with intermediate proliferation, where a scorbutic condition reduces neuronal differentiation. Vitamin C is a potent epigenetic regulator in stem cells; thus, it can induce the demethylation of DNA and histone H3K27m3 in the promoter region of genes involved in neurogenesis and differentiation, an effect mediated by Tet1 and Jmjd3 demethylases, respectively. In parallel, it has been shown that vitamin C induces the expression of stem cell-specific microRNA, including the Dlk1-Dio3 imprinting region and miR-143, which promotes stem cell self-renewal and suppresses expression of the methyltransferase gene Dnmt3a. The epigenetic action of vitamin C has also been evaluated during gene reprogramming of human fibroblasts to induced pluripotent cells, where it has been shown that vitamin C substantially improves the efficiency and quality of reprogrammed cells. Thus, for a proper effect of vitamin C on neurogenesis and differentiation, its function as an enzymatic cofactor, modulator of gene expression and antioxidant is essential, as is proper recycling from DHA to AA by various supporting cells in the CNS.
PubMed: 37424994
DOI: 10.3389/fnins.2023.1155758 -
Free Radical Biology & Medicine Sep 2023An excessive blood level of homocysteine (HcySH) is associated with numerous cardiovascular and neurodegenerative disease conditions. It has been suggested that direct...
An excessive blood level of homocysteine (HcySH) is associated with numerous cardiovascular and neurodegenerative disease conditions. It has been suggested that direct S-homocysteinylation, of proteins by HcySH, or N-homosteinylation by homocysteine thiolactone (HTL) could play a causative role in these maladies. In contrast, ascorbic acid (AA) plays a significant role in oxidative stress prevention. AA is oxidized to dehydroascorbic acid (DHA) and if not rapidly reduced back to AA may degrade to reactive carbonyl products. In the present work, DHA is shown to react with HTL to produce a spiro bicyclic ring containing a six-membered thiazinane-carboxylic acid moiety. This reaction product is likely formed by initial imine condensation and subsequent hemiaminal product followed by HTL ring opening and intramolecular nucleophilic attack of the resulting thiol anion to form the spiro product. The reaction product was determined to have an accurate mass of 291.0414 and a molecular composition CHNOS containing five double bond equivalents. We structurally characterized the reaction product using a combination of accurate mass tandem mass spectrometry, 1D and 2D-nuclear magnetic resonance. We also demonstrated that formation of the reaction product prevented peptide and protein N-homocysteinylation by HTL using a model peptide and α-lactalbumin. Furthermore, the reaction product is formed in Jurkat cells when exposed to HTL and DHA.
Topics: Humans; Dehydroascorbic Acid; Neurodegenerative Diseases; Peptides; Homocysteine
PubMed: 37385568
DOI: 10.1016/j.freeradbiomed.2023.06.031 -
Meat Science Oct 2023Raw beef patties were treated with either 450 ppm of Sodium metabisulphite (SMB), or Kakadu plum powder (KPP) (0.2%, 0.4%, 0.6%, 0.8%) or no additive (negative control)...
Kakadu plum (Terminalia ferdinandiana) bioactivity against spoilage microorganisms and oxidative reactions in refrigerated raw beef patties under modified atmosphere packaging.
Raw beef patties were treated with either 450 ppm of Sodium metabisulphite (SMB), or Kakadu plum powder (KPP) (0.2%, 0.4%, 0.6%, 0.8%) or no additive (negative control) and stored under Modified Atmosphere Packaging at 4 ± 1 °C for 20 days. Lipid oxidation, microbial growth rate, pH, instrumental color, and surface myoglobin were studied. Total phenolic compounds (TPC) and vitamin C of the KPP were also measured. The TPC was 13.9 g GAE/ 100 g dry weight (DW) and for vitamin C, the L-AA (l-ascorbic acid) and DHAA (dehydroascorbic acid) were 12.05 g/100 g and 0.5 g/ 100 g DW, respectively. The experimental results indicated that lipid oxidation was significantly delayed throughout the storage period for KPP-treated samples compared to both the negative control and SMB-treated samples. KPP at levels of 0.2% and 0.4% in the raw beef patties were efficient in slowing down the microbial growth rate compared to the negative control; however, SMB had a higher antimicrobial activity. The pH, the redness as well as metmyoglobin formation in the raw beef patties were reduced by the inclusion of the KPP in treated samples. A correlation (r = -0.66) was noted between KPP treatments and lipid oxidation, but there was no correlation (r = -0.006) between KPP treatment and microbial growth. This study demonstrates that KPP could be used as natural preservative for shelf-life extension of raw beef patties.
Topics: Animals; Cattle; Terminalia; Prunus domestica; Ascorbic Acid; Lipids; Atmosphere; Oxidative Stress
PubMed: 37379705
DOI: 10.1016/j.meatsci.2023.109268 -
International Journal of Molecular... May 2023Melatonin (MT) and nitric oxide (NO) act as signaling molecules that can enhance cadmium (Cd) stress resistance in plants. However, little information is available about...
Melatonin (MT) and nitric oxide (NO) act as signaling molecules that can enhance cadmium (Cd) stress resistance in plants. However, little information is available about the relationship between MT and NO during seedling growth under Cd stress. We hypothesize that NO may be involved in how MT responds to Cd stress during seedling growth. The aim of this study is to evaluate the relationship and mechanism of response. The results indicate that different concentrations of Cd inhibit the growth of tomato seedlings. Exogenous MT or NO promotes seedling growth under Cd stress, with a maximal biological response at 100 μM MT or NO. The promotive effects of MT-induced seedling growth under Cd stress are suppressed by NO scavenger 2-4-carboxyphenyl-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide (cPTIO), suggesting that NO may be involved in MT-induced seedling growth under Cd stress. MT or NO decreases the content of hydrogen peroxide (HO), malonaldehyde (MDA), dehydroascorbic acid (DHA), and oxidized glutathione (GSSG); improves the content of ascorbic acid (AsA) and glutathione (GSH) and the ratios of AsA/DHA and GSH/GSSG; and enhances the activities of glutathione reductase (GR), monodehydroascorbic acid reductase (MDHAR), dehydroascorbic acid reductase (DHAR), ascorbic acid oxidase (AAO), and ascorbate peroxidase (APX) to alleviate oxidative damage. Moreover, the expression of genes associated with the ascorbate-glutathione (AsA-GSH) cycle and reactive oxygen species (ROS) are up-regulated by MT or NO under Cd conditions, including , , , , , , , and . However, NO scavenger cPTIO reverses the positive effects regulated by MT. The results indicate that MT-mediated NO enhances Cd tolerance by regulating AsA-GSH cycle and ROS metabolism.
Topics: Antioxidants; Melatonin; Seedlings; Cadmium; Nitric Oxide; Reactive Oxygen Species; Solanum lycopersicum; Glutathione Disulfide; Dehydroascorbic Acid; Hydrogen Peroxide; Ascorbic Acid; Oxidative Stress; Glutathione; Oxidoreductases
PubMed: 37298477
DOI: 10.3390/ijms24119526 -
Toxins Apr 2023Aflatoxins (AFs) are toxic secondary metabolites produced by spp. and are found in food and feed as contaminants worldwide. Due to climate change, AFs occurrence is...
Aflatoxins (AFs) are toxic secondary metabolites produced by spp. and are found in food and feed as contaminants worldwide. Due to climate change, AFs occurrence is expected to increase also in western Europe. Therefore, to ensure food and feed safety, it is mandatory to develop green technologies for AFs reduction in contaminated matrices. With this regard, enzymatic degradation is an effective and environmentally friendly approach under mild operational conditions and with minor impact on the food and feed matrix. In this work, Ery4 laccase, acetosyringone, ascorbic acid, and dehydroascorbic acid were investigated in vitro, then applied in artificially contaminated corn for AFB reduction. AFB (0.1 µg/mL) was completely removed in vitro and reduced by 26% in corn. Several degradation products were detected in vitro by UHPLC-HRMS and likely corresponded to AFQ, epi-AFQ, AFB-diol, or AFBdialehyde, AFB, and AFM. Protein content was not altered by the enzymatic treatment, while slightly higher levels of lipid peroxidation and HO were detected. Although further studies are needed to improve AFB reduction and reduce the impact of this treatment in corn, the results of this study are promising and suggest that Ery4 laccase can be effectively applied for the reduction in AFB in corn.
Topics: Aflatoxin B1; Zea mays; Hydrogen Peroxide; Laccase; Aflatoxins
PubMed: 37235345
DOI: 10.3390/toxins15050310 -
Journal of Plant Physiology Jul 2023Numerous studies report different types of responses following exposure of plants to high frequency electromagnetic fields (HF-EMF). While this phenomenon is related to...
Numerous studies report different types of responses following exposure of plants to high frequency electromagnetic fields (HF-EMF). While this phenomenon is related to tissue heating in animals, the situation is much less straightforward in plants where metabolic changes seem to occur without tissue temperature increase. We have set up an exposure system allowing reliable measurements of tissue heating (using a reflectometric probe and thermal imaging) after a long exposure (30 min) to an electromagnetic field of 2.45 GHz transmitted through a horn antenna (about 100 V m at the plant level). We did not observe any heating of the tissues, but we detected rapid increases (60 min) in the accumulation of transcripts of stress-related genes (TCH1 and ZAT12 transcription factor) or involved in ROS metabolism (RBOHF and APX1). At the same time, the amounts of hydrogen peroxide and dehydroascorbic acid increased while glutathione (reduced and oxidized forms), ascorbic acid, and lipid peroxidation remained stable. Therefore, our results unambiguously show that molecular and biochemical responses occur rapidly (within 60min) in plants after exposure to an electromagnetic field, in absence of tissue heating.
Topics: Animals; Arabidopsis; Electromagnetic Fields; Plants; Hydrogen Peroxide; Lipid Peroxidation
PubMed: 37210775
DOI: 10.1016/j.jplph.2023.153999 -
Nanoscale Jun 2023Cancer cells tend to have higher intracellular reactive oxygen species (ROS) levels and are more vulnerable to ROS-generating therapies such as ascorbic acid (HAsc)...
Cancer cells tend to have higher intracellular reactive oxygen species (ROS) levels and are more vulnerable to ROS-generating therapies such as ascorbic acid (HAsc) therapy, whose potency has been explored by several clinical trials. However, its efficiency is restricted by the requirement of pharmacologically high local HAsc concentrations. Here, we show that nitrogen-doped graphene oxide dots (NGODs), which are highly crystalline and biocompatible, can serve as a catalytic medium for improving HAsc cancer therapy at orally achievable physiological HAsc concentrations. NGODs catalyze HAsc oxidation for HO and dehydroascorbic acid generation to disrupt cancer cells by consuming intracellular glutathione (GSH) and inducing ROS damage. This is the first study to demonstrate the direct consumption of GSH using a carbon-based nano-catalyst (NGODs), which further expedites tumor killing. In addition, as in our previous study, NGODs can also serve as a highly efficient photosensitizer for photodynamic therapy. Under illumination, NGODs produce a considerable amount of HO in the presence of physiological levels of HAsc as a hole scavenger and further enhance the therapeutic efficiency. Thus, a concise nanotherapeutic modality could be achieved through the conjunction of multifunctional NGODs and HAsc to selectively eliminate deep-seated and superficial tumors simultaneously (under 65% of normal cell viability, it kills almost all cancer cells). Note that this level of therapeutic versatility generally requires multiple components and complex manufacturing processes that run into difficulties with FDA regulations and clinical applications. In this study, the concise NGOD-HAsc nanotherapeutic modality has demonstrated its great potential in cancer therapy.
Topics: Humans; Ascorbic Acid; Reactive Oxygen Species; Hydrogen Peroxide; Photochemotherapy; Neoplasms; Glutathione; Cell Line, Tumor
PubMed: 37183719
DOI: 10.1039/d3nr00431g