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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 -
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