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ACS Omega Jan 2022Rosmarinic acid-capped silver nanoparticles (Ro-AgNPs) were prepared and applied as a probe for selective colorimetric detection of cyanide (CN) and chromium(VI)...
Rosmarinic acid-capped silver nanoparticles (Ro-AgNPs) were prepared and applied as a probe for selective colorimetric detection of cyanide (CN) and chromium(VI) [Cr(VI)] under different conditions in aqueous media. The carbon atom of CN interacts with the AgNPs, and the carbon atom donates electrons from the HOMO to the vacant orbitals of the coordinatively unsaturated surface atom (Ag). After donating electrons, CN attached onto the surface of the nanoparticles becomes very reactive and interacts with dissolved oxygen and generates reactive oxygen species (ROS) such as superoxide (O ), singlet oxygen (O), and so forth. In this process, Ag oxidizes to Ag and combines with CN forming water-insoluble AgCN, and the ROS (O ) formed reacts with Ag/Ag to form AgO. The oxidation of Ag to Ag resulted in dissolution of AgNPs, which causes disappearance of the surface plasmon resonance band and color change from yellow to colorless. For detection of Cr(VI), ascorbic acid and CN were added first; the ascorbic acid replaced the rosmarinic acid and then reduced the added Cr(VI) to Cr(III), and, in this process, ascorbic acid was oxidized to dehydroascorbic acid, which moved away from the nanoparticles' surface. CN then interacted with the surface Ag atom, got activated, and interacted with dissolved oxygen forming Ag and ROS, which then followed the same process as described for CN to form AgCN and AgO with a color change. The limits of detection were found to be 0.01 and 0.03 μM for CN and Cr(VI), respectively. The material was also used for sensing CN and Cr(VI) in real samples, and the results obtained were satisfactory. For field application, agarose-based strips were prepared by immobilizing the nanoparticles onto the agarose film and successfully used for the detection of CN and Cr(VI) in water.
PubMed: 35036793
DOI: 10.1021/acsomega.1c05946 -
Frontiers in Plant Science 2022Pepper is one of the most vitamin C enriched vegetables worldwide. Although applying nitrogen (N) fertilizer is an important practice for high fruit yield in pepper...
Pepper is one of the most vitamin C enriched vegetables worldwide. Although applying nitrogen (N) fertilizer is an important practice for high fruit yield in pepper production, it is still unclear how N application regulates pepper fruit vitamin C anabolism at different maturity stage. To further the understanding, we combined physiological and metabolomic analysis to investigate the fruit vitamin C content (including ascorbic acid (AsA) and dehydroascorbic acid (DHA)), related enzyme activity and non-targeted metabolites of field-grown chili pepper produced under different N levels at mature green and red stages. The results showed that increasing N application reduced AsA content in pepper fruit at both maturity stages, but highly elevated DHA content only at mature green stage. Regardless of N application level, AsA content displayed an increasing trend while DHA content was reduced as pepper fruit maturity advanced, resulting in a higher content of total vitamin C at the mature green stage. The L-galactose pathway, D-galacturonate pathway, and myo-inositol pathway were identified for AsA biosynthesis. The involved precursor metabolites were mainly negatively regulated by increasing N application, and their accumulation increased when pepper fruit developed from green to red stage. Meanwhile, the activities of key enzymes and metabolites in relation to degradation and recycling processes of AsA and DHA were increased or did not change with increasing N application, and they were differently influenced as fruit maturing. As a result, the recommended N application level (250 kg N ha) could maintain relatively high total vitamin C content in pepper fruits without yield loss at both maturity stages. These findings highlight the importance of optimizing N application level to maximize vitamin C content in pepper fruits, and provide a better understanding of the maturity stage-dependent N regulation on vitamin C anabolism.
PubMed: 36714702
DOI: 10.3389/fpls.2022.1049785 -
Antioxidants (Basel, Switzerland) Dec 2020The reduced form of vitamin C, ascorbic acid (AA), has been related with gene expression and cell differentiation in the cerebral cortex. In neurons, AA is mainly...
The reduced form of vitamin C, ascorbic acid (AA), has been related with gene expression and cell differentiation in the cerebral cortex. In neurons, AA is mainly oxidized to dehydroascorbic acid (DHA); however, DHA cannot accumulate intracellularly because it induces metabolic changes and cell death. In this context, it has been proposed that vitamin C recycling via neuron-astrocyte coupling maintains AA levels and prevents DHA parenchymal accumulation. To date, the role of this mechanism during the outgrowth of neurites is unknown. To stimulate neuronal differentiation, adhered neurospheres treated with AA and retinoic acid (RA) were used. Neuritic growth was analyzed by confocal microscopy, and the effect of vitamin C recycling (bystander effect) in vitro was studied using different cells. AA stimulates neuritic growth more efficiently than RA. However, AA is oxidized to DHA in long incubation periods, generating a loss in the formation of neurites. Surprisingly, neurite growth is maintained over time following co-incubation of neurospheres with cells that efficiently capture DHA. In this sense, astrocytes have high capacity to recycle DHA and stimulate the maintenance of neurites. We demonstrated that vitamin C recycling in vitro regulates the morphology of immature neurons during the differentiation and maturation processes.
PubMed: 33327638
DOI: 10.3390/antiox9121276 -
Analytical Chemistry Dec 2022A photoelectrochemical (PEC) biosensor was established for histone deacetylase Sirt1 detection based on the polyaspartic acid (PASP)-mediated redox cycling amplification...
Photoelectrochemical Biosensor for Histone Deacetylase Sirt1 Detection Based on Polyaspartic Acid-Engaged and Triggered Redox Cycling Amplification and Enhanced Photoactivity of BiVO by Gold Nanoparticles and SnS.
A photoelectrochemical (PEC) biosensor was established for histone deacetylase Sirt1 detection based on the polyaspartic acid (PASP)-mediated redox cycling amplification and Sirt1 catalysis deacetylation-triggered recognition of the deacetylated substrate peptide, using PASP as the recognition reagent. After BiVO was composited with gold nanoparticles and SnS, the photoactivity of the composite was greatly enhanced due to the matched energy band structure. Under the catalysis of Sirt1 enzyme, the acetylated substrate peptide was deacetylated to obtain a positive peptide, which was recognized by negative PASP. In addition to the recognition function, PASP also played other triple roles. First, PASP interacted with the positive peptide to form a double-stranded structure, which led to the electrode interface changing from irregular to regular, resulting in an improved PEC response. Second, PASP was involved into redox cycle amplification due to its reduction to dehydroascorbic acid. Further, it was used for repeated preparation of ascorbic acid to provide electron donors. This process enhanced the PEC response. Third, based on the matched energy band with BiVO, PASP effectively improved the photoactivity of BiVO. With multiplex signal amplification, the PEC biosensor showed a wide linear range (1.83-1830 pM) and high detection sensitivity with a low detection limit of 0.732 pM (S/N = 3). The applicability of this method was evaluated by studying the effects of a known inhibitor of nicotinamide and the heavy metal ions of Cd and Pb on Sirt1 enzyme activity, and the results showed that this method not only provided a new platform for screening Sirt1 enzyme inhibitors but also provided new biomarkers for evaluating the ecotoxicological effects of environmental pollutants.
Topics: Biosensing Techniques; Electrochemical Techniques; Gold; Limit of Detection; Metal Nanoparticles; Oxidation-Reduction; Peptides; Sirtuin 1
PubMed: 36416225
DOI: 10.1021/acs.analchem.2c04380 -
Analytica Chimica Acta Jun 2022This work reported that the peptide-Cu complexes reveal oxidase-mimicking activities for oxygen reduction and ascorbate oxidation. The peptide features a histidine (His)...
This work reported that the peptide-Cu complexes reveal oxidase-mimicking activities for oxygen reduction and ascorbate oxidation. The peptide features a histidine (His) residue in the first position with respect to the free N-terminal amine. The complexes can be easily integrated with nanomaterials such as gold nanoparticles (AuNPs) to form nanocatalysts or nanozymes, which allows for the fabrication of sensitive sensing platforms. To explore the analytical performances of the peptide-Cu complexes in biosensing, sandwich electrochemical and fluorescent immunoassays of prostate specific antigen (PSA) were performed with AuNP/peptide-Cu conjugates as the nanolabels. In the electrochemical immunoassays, the nanolabels coined as nanocatalysts promoted the electrocatalytic reduction of oxygen. For the fluorescent assays of PSA, the nanolabels coined as nanozymes catalyzed the oxidation of ascorbic acid (AA), and the resulting oxidization product dehydroascorbic acid (DHA) was reacted with o-phenylenediamine (OPD) to form fluorescent 3-(dihydroxyethyl)furo [3,4-b]quinoxaline-1-one (DFQ). The electrochemical and fluorescent signals are proportional to the concentration of PSA in the linear range of 0.001-0.50 and 0.001-2.00 ng/mL, respectively. The low detection limits of the methods (0.40 and 1.00 pg/mL) enabled clinical detection of PSA in serum samples. The findings should be valuable for understanding the biological functions of peptide-Cu complexes, and provide new insight to develop optical and electrochemical sensing platforms for clinical diagnosis.
Topics: Biosensing Techniques; Copper; Gold; Humans; Male; Metal Nanoparticles; Oxidoreductases; Oxygen; Peptides; Prostate-Specific Antigen
PubMed: 35649645
DOI: 10.1016/j.aca.2022.339965 -
Acta Pharmaceutica Sinica. B Mar 2023As a neurological disorder in the brain, epilepsy is not only associated with abnormal synchronized discharging of neurons, but also inseparable from non-neuronal...
As a neurological disorder in the brain, epilepsy is not only associated with abnormal synchronized discharging of neurons, but also inseparable from non-neuronal elements in the altered microenvironment. Anti-epileptic drugs (AEDs) merely focusing on neuronal circuits frequently turn out deficient, which is necessitating comprehensive strategies of medications to cover over-exciting neurons, activated glial cells, oxidative stress and chronic inflammation synchronously. Therefore, we would report the design of a polymeric micelle drug delivery system that was functioned with brain targeting and cerebral microenvironment modulation. In brief, reactive oxygen species (ROS)-sensitive phenylboronic ester was conjugated with poly-ethylene glycol (PEG) to form amphiphilic copolymers. Additionally, dehydroascorbic acid (DHAA), an analogue of glucose, was applied to target glucose transporter 1 (GLUT1) and facilitate micelle penetration across the blood‒brain barrier (BBB). A classic hydrophobic AED, lamotrigine (LTG), was encapsulated in the micelles self-assembly. When administrated and transferred across the BBB, ROS-scavenging polymers were expected to integrate anti-oxidation, anti-inflammation and neuro-electric modulation into one strategy. Moreover, micelles would alter LTG distribution with improved efficacy. Overall, the combined anti-epileptic therapy might provide effective opinions on how to maximize neuroprotection during early epileptogenesis.
PubMed: 36970212
DOI: 10.1016/j.apsb.2022.09.019 -
Spectrochimica Acta. Part A, Molecular... Apr 2021A ratiometric fluorescence assay for alendronate (ALDS) has been designed with Ce-triggered cascade chromogenic reaction. This strategy involves three processes: (1) Ce...
A ratiometric fluorescence assay for alendronate (ALDS) has been designed with Ce-triggered cascade chromogenic reaction. This strategy involves three processes: (1) Ce oxidizes ascorbic acid (AA) into dehydroascorbic acid (DHAA), which then condenses with o-phenlenediamine (OPD) to generate fluorescent 3-(dihydroxyethyl)furo[3,4-b] quinoxaline-1-one (DFQ), presenting the maximum emission at 434 nm; (2) As oxidase-mimics, Ce can oxidize OPD into fluorescent 2,3-diaminophenazine (DAP) which shows a strong emission at 568 nm; (3) ALDS inhibits the oxidation ability of Ce towards OPD, thus inhibiting the generation of DAP. Accordingly, a homogeneous ratiometric fluorescence system with dual emission comes into being and the presence of ALDS can change the fluorescence intensity ratio obviously. With F/F as readout, ALDS can be detected sensitively with the detection limit of 30 nM. Moreover, this ratiometric method was used to analyze ALDS in both human serum and pharmaceutical samples.
Topics: Alendronate; Ascorbic Acid; Fluorescence; Humans; Oxidation-Reduction; Spectrometry, Fluorescence
PubMed: 33461138
DOI: 10.1016/j.saa.2021.119437 -
Clinical, Cosmetic and Investigational... 2022Skin involvement is the second most common symptom of systemic lupus erythematosus (SLE), and the prevention of skin lesion development might benefit to lessen the...
PURPOSE
Skin involvement is the second most common symptom of systemic lupus erythematosus (SLE), and the prevention of skin lesion development might benefit to lessen the system inflammation burden in SLE. However, the mechanisms of skin lesion in SLE remain unclear.
PATIENTS AND METHODS
Metabolome based on gas chromatography-mass spectrometry (GC-MS) was used for comparison of serum metabolism among 11 SLE patients with skin lesion (SL), 10 SLE patients without skin lesion (SNL), and 16 healthy controls (HC). The analysis of metabolism profiles was through LUG database, Human Metabolome Database (HMDB) as well as Kyoto Encyclopedia of Genes and Genomes (KEGG).
RESULTS
A total of 14 most meaningful metabolites were found in SL patients compared to SNL patients, and 19 metabolic pathways were enriched. Meanwhile, L-alpha-aminobutyric acid, dehydroascorbic acid, glycine, and L-tyrosine achieved an area under receiver-operating characteristic (ROC) curve of 0.8636, 0.8091, 0.7727, and 0.7636, respectively, indicating their diagnostic potential for SL patients. In addition, the combined model of L-alpha-aminobutyric acid and dehydroascorbic acid provided better diagnostic accuracy.
CONCLUSION
The metabolomic features of SLE patients with skin lesion could be detected by GC/MS assay. Our study tried to provide new insights into the mechanism of SLE skin injury. Further validation of these findings through larger sample size studies may contribute to the use of metabolic profile analysis.
PubMed: 35082507
DOI: 10.2147/CCID.S345372 -
The Science of the Total Environment Nov 2022The ecotoxicity of tungsten disulfide (WS) nanomaterials remains unclear so far. Here, the toxicity of WS nanosheets on N-fixing cyanobacteria (Nostoc sphaeroides) was...
The ecotoxicity of tungsten disulfide (WS) nanomaterials remains unclear so far. Here, the toxicity of WS nanosheets on N-fixing cyanobacteria (Nostoc sphaeroides) was evaluated. Specifically, Nostoc were cultivated in media spiked with different concentrations of WS nanosheets (0, 0.05, 0.1 and 0.5 mg/L) for 96 h. Relative to unexposed cells, WS nanosheets at 0.5 mg/L significantly decreased cell density, content of total sugar and protein by 10.9 %, 0.43 %, and 6.1 %, respectively. Gas chromatography-mass spectrometry (GC-MS)-based metabolomics revealed that WS nanosheets exposure altered the metabolite profile of Nostoc in a dose-dependent manner. Energy metabolism related pathways, including the Calvin-Benson-Bassham (CBB) cycle and tricarboxylic acid (TCA) cycle, were significantly inhibited. In addition, WS nanosheets exposure resulted in downregulation (20-40 %) of S-containing amino acids (cystine, methionine, and cysteine) and sulfuric acid. Additionally, fatty acids and antioxidant-related compounds (formononetin, catechin, epigallocatechin, dehydroascorbic acid, and alpha-tocopherol) in Nostoc were drastically decreased by 4-50 % upon exposure to WS nanosheets, which implies oxidative stress induced by the nanomaterials. Biochemical assays for reactive oxygen species (ROS) and malondialdehyde (MDA) confirmed that WS nanosheets triggered ROS overproduction and induced lipid peroxidation. Taken together, WS exposure perturbed carbon (C), nitrogen (N), and sulfate (S) metabolism of Nostoc, which may influence C, N, and S cycling, given the important roles of cyanobacteria in these processes. These results highlight the need for caution in the application and environmental release of WS nanomaterials to prevent unintended environmental impacts due to their potential ecotoxicity.
Topics: Antioxidants; Carbon; Catechin; Cell Membrane; Cysteine; Cystine; Dehydroascorbic Acid; Fatty Acids; Malondialdehyde; Methionine; Nitrogen; Reactive Oxygen Species; Sugars; Sulfates; Sulfides; Sulfuric Acids; Tricarboxylic Acids; Tungsten Compounds; alpha-Tocopherol
PubMed: 35908696
DOI: 10.1016/j.scitotenv.2022.157706 -
Frontiers in Plant Science 2021As an important plant growth regulator, the role of γ-aminobutyric acid (GABA) in regulating seeds germination was less well elucidated under water stress. The present...
γ-Aminobutyric Acid (GABA) Priming Improves Seed Germination and Seedling Stress Tolerance Associated With Enhanced Antioxidant Metabolism, Expression, and Dehydrin Accumulation in White Clover Under Water Stress.
As an important plant growth regulator, the role of γ-aminobutyric acid (GABA) in regulating seeds germination was less well elucidated under water stress. The present study was conducted to investigate the impact of GABA pretreatment on seeds germination of white clover () under water deficient condition. Results demonstrated that seeds pretreated with 2μmol/l GABA significantly alleviated decreases in endogenous GABA content, germination percentage, germination potential, germination index, root length, and fresh weight along with marked reduction in mean germination time after 7days of germination under drought stress. In addition, seeds priming with GABA significantly increased the accumulation of soluble sugars, non-enzymatic antioxidants [reduced ascorbate, dehydroascorbic acid, oxidized glutathione (GSSG), and reduced glutathione (GSH)], and enzymes [superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathioe reductase, and monodehydroasorbate reductase (MDHR)] activities involved in antioxidant metabolism, which could be associated with significant reduction in osmotic potential and the accumulation of superoxide anion, hydrogen peroxide, electrical leakage, and malondialdehyde in seeds under drought stress. The GABA-pretreated seeds exhibited significantly higher abundance of dehydrin (DHN, 56 KDa) and expression levels of DHNs encoding genes (, , , and ) and transcription factors (, , , and ) than the untreated seeds during germination under water-limited condition. These results indicated that the GABA regulated improvement in seeds germination associated with enhancement in osmotic adjustment, antioxidant metabolism, and -related expression. Current study will provide a better insight about the GABA-regulated defense mechanism during seeds germination under water-limited condition.
PubMed: 34925419
DOI: 10.3389/fpls.2021.776939