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Fulltext Over-expression of Nicotinamide phosphoribosyltransferase in mouse cells confers protective effect against oxidative and ER stress-induced premature senescence

Nuriliani A, Nakahata Y, Ahmed R, Khaidizar FD, Matsui T, Bessho Y

Genes Cells, 2020 Aug;25(8):593-602.
PMID: 32533606 DOI: 10.1111/gtc.12794

A main feature of aged organisms is the accumulation of senescent cells. Accumulated senescent cells, especially stress-induced premature senescent cells, in aged organisms lead to the decline of the regenerative potential and function of tissues. We recently reported that the over-expression of NAMPT, which is the rate-limiting enzyme in mammalian NAD+ salvage pathway, delays replicative senescence in vitro. However, whether Nampt-overexpressing cells are tolerant of stress-induced premature senescence remains unknown. Here, we show that primary mouse embryonic fibroblasts derived from Nampt-overexpressing transgenic mice (Nampt Tg-MEF cells) possess resistance against stress-induced premature senescence in vitro. We found that higher oxidative or endoplasmic reticulum (ER) stress is required to induce premature senescence in Nampt Tg-MEF cells compared to wild-type cells. Moreover, we found that Nampt Tg-MEF cells show acute expression of unfolded protein response (UPR)-related genes, which in turn would have helped to restore proteostasis and avoid cellular senescence. Our results demonstrate that NAMPT/NAD+ axis functions to protect cells not only from replicative senescence, but also from stress-induced premature senescence in vitro. We anticipate that in vivo activation of NAMPT activity or increment of NAD+ would protect tissues from the accumulation of premature senescent cells, thereby maintaining healthy aging.

Matched MeSH terms: Oxidation-Reduction
Fulltext Proteomics analysis on lipid metabolism in Elaeis guineensis and Elaeis oleifera

Lau BYC, Amiruddin MD, Othman A

Data Brief, 2020 Aug;31:105714.
PMID: 32462070 DOI: 10.1016/j.dib.2020.105714

Proteome data was obtained from the fruit mesocarps of the two oil palm species, namely, the African Elaeis guineensis (commercial tenera or commonly known as D x P and MPOB-Nigerian tenera) and the South American Elaeis oleifera. Total proteins were extracted from randomly selected fruitlets and subjected to proteomics characterisation by means of liquid chromatography mass spectrometry. Number of proteins identified, the grouping of the biological replicates from five developmental weeks after anthesis, and the localisation of gene corresponded to the detected proteins on the oil palm chromosomes, were presented. A total of 4,116, 4,210 and 4,081 proteins were found in commercial tenera and MPOB Nigerian tenera for Elaeis guineensis; and Elaeis oleifera, respectively. Principal component analysis showed two distinct clusters that corresponded to Elaeis guineensis and Elaeis oleifera. Collectively, genes that corresponded to the identified proteins were found to be located in all 16 oil palm chromosomes. A total of 59 proteins from Elaeis guineensis and Elaeis oleifera were down-regulated for >5-fold change during the peak of lipid biosynthesis compared to the onset. The same comparative analysis revealed that 66 proteins were up-regulated for >5-fold change. About 60.0% of the observed proteins were involved in catalytic activity while 28.5% were associated with redox reaction. Based on same datasets, the tricarboxylic acid cycle and 5-hydroxytryptamine degradation pathways were found to be enriched the most (>36-fold change). These data can be used to support the oil palm gene model validation and lipid metabolism research, particularly in the areas of oil yield and quality. The tabulated protein lists of identified proteins and their expression changes from these varieties were provided as supplementary files. Raw MSF and mzid files for all the oil palm species were deposited in the ProteomeXchange (PXD017436).

Matched MeSH terms: Oxidation-Reduction
Electrochemical Long Period Fiber Grating Sensing for Electroactive Species

Okazaki T, Orii T, Tan SY, Watanabe T, Taguchi A, Rahman FA, et al.

Anal Chem, 2020 07 21;92(14):9714-9721.
PMID: 32551577 DOI: 10.1021/acs.analchem.0c01062

We present an electrochemical long period fiber grating (LPFG) sensor for electroactive species with an optically transparent electrode. The sensor was fabricated by coating indium tin oxide onto the surface of LPFG using a polygonal barrel-sputtering method. LPFG was produced by an electric arc-induced technique. The sensing is based on change in the detection of electron density on the electrode surface during potential application and its reduction by electrochemical redox of analytes. Four typical electroactive species of methylene blue, hexaammineruthenium(III), ferrocyanide, and ferrocenedimethanol were used to investigate the sensor performance. The concentrations of analytes were determined by the modulation of the potential as the change in transmittance around the resonance band of LPFG. The sensitivity of the sensor, particularly to methylene blue, was high, and the sensor responded to a wide concentration range of 0.001 mM to 1 mM.

Matched MeSH terms: Oxidation-Reduction
Sorption of ionized dyes on high-salinity microalgal residue derived biochar: Electron acceptor-donor and metal-organic bridging mechanisms

Tan X, Zhu S, Show PL, Qi H, Ho SH

J Hazard Mater, 2020 07 05;393:122435.
PMID: 32151933 DOI: 10.1016/j.jhazmat.2020.122435

Biochar (BC) has attracted much attention owing to its superior sorption capacity towards ionized organic contaminants. However, the mechanism of ionized organics sorption occurring within BC containing large amounts of minerals is still controversial. In this study, we demonstrate the physicochemical structure of high-salinity microalgal residue derived biochar (HSBC) and elucidate the corresponding sorption mechanisms for four ionized dyes along with determining the crucial role of involved minerals. The results indicate that sodium and calcium minerals mainly exist within HSBCs, and the pyrolysis temperature can dramatically regulate the phases and interfacial property of both carbon matrix and minerals. As a result, the HSBC shows a higher sorption potential, benefiting from abundant functional groups and high content of inorganic minerals. Using theoretical calculations, the activities of electron donor-acceptor interaction between HSBCs and different dyes are clearly illustrated, thereby identifying the critical role of Ca2+ in enhancing the removal of ionized dyes in HSBCs. In addition, Ca-containing minerals facilitate the sorption of ionized dyes in HSBCs by forming ternary complexes through metal-bridging mechanism. These results of mineral-induced dye sorption mechanisms help to better understand the sorption of ionized organics in high-salt containing BC and provide a new disposal strategy for hazardous microalgal residue, as well as provide a breakthrough in making the remediation of ionized organic contaminated microalgal residue derived absorbent feasible.

Matched MeSH terms: Oxidation-Reduction
Fulltext Ultrasonic Assisted Synthesis of Size-Controlled Cu-Metal-Organic Framework Decorated Graphene Oxide Composite: Sustainable Electrocatalyst for the Trace-Level Determination of Nitrite in Environmental Water Samples

Arul P, Gowthaman NSK, John SA, Lim HN

ACS Omega, 2020 Jun 23;5(24):14242-14253.
PMID: 32596560 DOI: 10.1021/acsomega.9b03829

Excess levels of nitrite ion in drinking water interact with amine functionalized compounds to form carcinogenic nitrosamines, which cause stomach cancer. Thus, it is indispensable to develop a simple protocol to detect nitrite. In this paper, a Cu-metal-organic framework (Cu-MOF) with graphene oxide (GO) composite was synthesized by ultrasonication followed by solvothermal method and then fabricated on a glassy carbon (GC) electrode for the sensitive and selective determination of nitrite contamination. The SEM image of the synthesized Cu-MOF showed colloidosome-like structure with an average size of 8 μm. Interestingly, the Cu-MOF-GO composite synthesized by ultrasonic irradiation followed by solvothermal process produce controlled size of 3 μm colloidosome-like structure. This was attributed to the formation of an exfoliated sheet-like structure of GO by ultrasonication in addition to the obvious influence of GO providing the oxygen functional groups as a nucleation node for size-controlled growth. On the other hand, the composite prepared without ultrasonication exhibited 6.6 μm size agglomerated colloidosome-like structures, indicating the crucial role of ultrasonication for the formation of size-controlled composites. XPS results confirmed the presence of Cu(II) in the as-synthesized Cu-MOF-GO based on the binding energies at 935.5 eV for Cu 2p3/2 and 955.4 eV for Cu 2p1/2. The electrochemical impedance studies in [Fe(CN)6]3-/4- redox couple at the composite fabricated electrode exhibited more facile electron transfer than that with Cu-MOF and GO modified electrodes, which helped to utilize Cu-MOF-GO for trace level determination of nitrite in environmental effluent samples. The Cu-MOF-GO fabricated electrode offered a superior sensitive platform for nitrite determination than the Cu-MOF and GO modified electrodes demonstrating oxidation at less positive potential with enhanced oxidation current. The present sensor detects nitrite in the concentration range of 1 × 10-8 to 1 × 10-4 M with the lowest limit of detection (LOD) of 1.47 nM (S/N = 3). Finally, the present Cu-MOF-GO electrode was successfully exploited for nitrite ion determination in lake and dye contaminated water samples.

Matched MeSH terms: Oxidation-Reduction
Fulltext Synergetic Effects of Hybrid Carbon Nanostructured Counter Electrodes for Dye-Sensitized Solar Cells: A Review

Samantaray MR, Mondal AK, Murugadoss G, Pitchaimuthu S, Das S, Bahru R, et al.

Materials (Basel), 2020 Jun 19;13(12).
PMID: 32575516 DOI: 10.3390/ma13122779

This article provides an overview of the structural and physicochemical properties of stable carbon-based nanomaterials and their applications as counter electrodes (CEs) in dye-sensitized solar cells (DSSCs). The research community has long sought to harvest highly efficient third-generation DSSCs by developing carbon-based CEs, which are among the most important components of DSSCs. Since the initial introduction of DSSCs, Pt-based electrodes have been commonly used as CEs owing to their high-electrocatalytic activities, thus, accelerating the redox couple at the electrode/electrolyte interface to complete the circuit. However, Pt-based electrodes have several limitations due to their cost, abundance, complicated facility, and low corrosion resistance in a liquid electrolyte, which further restricts the large-area applications of DSSCs. Although carbon-based nanostructures showed the best potential to replace Pt-CE of DSSC, several new properties and characteristics of carbon-CE have been reported for future enhancements in this field. In this review, we discuss the detailed synthesis, properties, and performances of various carbonaceous materials proposed for DSSC-CE. These nano-carbon materials include carbon nanoparticles, activated carbon, carbon nanofibers, carbon nanotube, two-dimensional graphene, and hybrid carbon material composites. Among the CE materials currently available, carbon-carbon hybridized electrodes show the best performance efficiency (up to 10.05%) with a high fill factor (83%). Indeed, up to 8.23% improvements in cell efficiency may be achieved by a carbon-metal hybrid material under sun condition. This review then provides guidance on how to choose appropriate carbon nanomaterials to improve the performance of CEs used in DSSCs.

Matched MeSH terms: Oxidation-Reduction
Fulltext Artocarpus altilis extracts as a food-borne pathogen and oxidation inhibitors: RSM, COSMO RS, and molecular docking approaches

Ahmad MN, Karim NU, Normaya E, Mat Piah B, Iqbal A, Ku Bulat KH

Sci Rep, 2020 06 12;10(1):9566.
PMID: 32533034 DOI: 10.1038/s41598-020-66488-7

Lipid oxidation and microbial contamination are the major factors contributing to food deterioration. Food additives like antioxidants and antibacterials can prevent food spoilage by delaying oxidation and preventing the growth of bacteria. Artocarpus altilis leaves exhibited biological properties that suggested its use as a new source of natural antioxidant and antimicrobial. Supercritical fluid extraction (SFE) was used to optimize the extraction of bioactive compounds from the leaves using response surface methodology (yield and antioxidant activity). The optimum SFE conditions were 50.5 °C temperature, 3784 psi pressure and 52 min extraction time. Verification test results (Tukey's test) showed that no significant difference between the expected and experimental DPPH activity and yield value (99%) were found. Gas-chromatography -mass spectrometry (GC-MS) analysis revealed three major bioactive compounds existed in A. altilis extract. The extract demonstrated antioxidant and antibacterial properties with 2,3-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, ferric reducing ability of plasma (FRAP), hydroxyl radical scavenging activity, tyrosinase mushrrom inhibition of 41.5%, 8.15 ± 1.31 (µg of ascorbic acid equivalents), 32%, 37% and inhibition zone diameter of 0.766 ± 0.06 cm (B. cereus) and 1.27 ± 0.12 cm (E. coli). Conductor like screening model for real solvents (COSMO RS) was performed to explain the extraction mechanism of the major bioactive compounds during SFE. Molecular electrostatic potential (MEP) shows the probability site of nucleophilic and electrophilic attack during bacterial inhibition. Based on molecular docking study, non-covalent interactions are the main interaction occurring between the major bioactive compounds and bacteria (antibacterial inhibition).

Matched MeSH terms: Oxidation-Reduction
Fulltext Response Factorial Design Analysis on Papain-Generated Hydrolysates from Actinopyga lecanora for Determination of Antioxidant and Antityrosinase Activities

Bahari AN, Saari N, Salim N, Ashari SE

Molecules, 2020 Jun 08;25(11).
PMID: 32521731 DOI: 10.3390/molecules25112663

Actinopyga lecanora (A. lecanora) is classified among the edible species of sea cucumber, known to be rich in protein. Its hydrolysates were reported to contain relatively high antioxidant activity. Antioxidants are one of the essential properties in cosmeceutical products especially to alleviate skin aging. In the present study, pH, reaction temperature, reaction time and enzyme/substrate ratio (E/S) have been identified as the parameters in the papain enzymatic hydrolysis of A. lecanora. The degree of hydrolysis (DH) with antioxidant activities of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric-reducing antioxidant power (FRAP) assays were used as the responses in the optimization. Analysis of variance (ANOVA), normal plot of residuals and 3D contour plots were evaluated to study the effects and interactions between parameters. The best conditions selected from the optimization were at pH 5.00, 70 °C of reaction temperature, 9 h of hydrolysis time and 1.00% enzyme/substrate (E/S) ratio, with the hydrolysates having 51.90% of DH, 42.70% of DPPH activity and 109.90 Fe2+μg/mL of FRAP activity. The A. lecanora hydrolysates (ALH) showed a high amount of hydrophobic amino acids (286.40 mg/g sample) that might be responsible for antioxidant and antityrosinase activities. Scanning electron microscopy (SEM) image of ALH shows smooth structures with pores. Antityrosinase activity of ALH exhibited inhibition of 31.50% for L-tyrosine substrate and 25.40% for L-DOPA substrate. This condition suggests that the optimized ALH acquired has the potential to be used as a bioactive ingredient for cosmeceutical applications.

Matched MeSH terms: Oxidation-Reduction
Potential toxic effects of chlorination and UV/chlorination in the treatment of hydrochlorothiazide in the water

Mansor NA, Tay KS

Sci Total Environ, 2020 Apr 20;714:136745.
PMID: 31982754 DOI: 10.1016/j.scitotenv.2020.136745

Chlorination is a common disinfection method in water treatment. This method can be converted into an advanced oxidation process by incorporating UV irradiation during water treatment. This study investigated the degradation of hydrochlorothiazide (HCTZ) by chlorination and UV/chlorination in water. HCTZ is a diuretic medication that has been frequently detected in wastewater. For chlorination, the second-order rate constant for the reaction between HCTZ with free available chlorine was found to increase with increasing pH from 5 to 8 due to the increase of the anionic HCTZ fraction. UV/chlorination was found to be more efficient in removing HCTZ as compared with chlorination due to the presence of reactive radical species such as hydroxyl radicals. For transformation by-products, chlorination was found to produce two by-products via chlorination and hydroxylation reactions that occurred at the aromatic ring of HCTZ. For UV/chlorination, an additional by-product formed through a radical reaction at the heterocyclic moiety of HCTZ was detected. Based on the Escherichia coli inhibition study, chlorination and UV/chlorination were found to increase the toxicity of the HCTZ solution. This result indicated that even UV/chlorination showed higher effectiveness in removing HCTZ; however, it also has the potential to generate toxic by-products and effluent.

Matched MeSH terms: Oxidation-Reduction
Fulltext Simultaneous biological nitrification and desulfurization treatment of ammonium and sulfide-rich wastewater: Effectiveness of a sequential batch operation

Sekine M, Akizuki S, Kishi M, Kurosawa N, Toda T

Chemosphere, 2020 Apr;244:125381.
PMID: 31805460 DOI: 10.1016/j.chemosphere.2019.125381

Sulfide inhibition to nitrifying bacteria has prevented the integration of digestate nitrification and biogas desulfurization to simplify anaerobic digestion systems. In this study, liquid digestate with NaHS solution was treated using nitrifying sludge in a sequential-batch reactor with a long fill period, with an ammonium loading rate of 293 mg-N L-1 d-1 and a stepwise increase in the sulfide loading rate from 0 to 32, 64, 128, and 256 mg-S L-1 d-1. Batch bioassays and microbial community analysis were also conducted with reactor sludge under each sulfide loading rate to quantify the microbial acclimatization to sulfide. In the reactor, sulfide was completely removed. Complete nitrification was maintained up to a sulfide load of 128 mg-S L-1 d-1, which is higher than that in previous reports and sufficient for biogas treatment. In the batch bioassays, the sulfide tolerance of NH4+ oxidizing activity (the 50% inhibitory sulfide concentration) increased fourfold over time with the compositional shift of nitrifying bacteria to Nitrosomonas nitrosa and Nitrobacter spp. However, the sulfur removal rate of the sludge slightly decreased, although the abundance of the sulfur-oxidizing bacteria Hyphomicrobium increased by 30%. Therefore, nitrifying sludge was probably acclimatized to sulfide not by the increasing sulfide removal rate but rather by the increasing nitrifying bacteria, which have high sulfide tolerance. Successful simultaneous nitrification and desulfurization were achieved using a sequential-batch reactor with a long fill period, which was effective in facilitating the present acclimatization.

Matched MeSH terms: Oxidation-Reduction
Hydroxyl radical formation in the hybrid system of photocatalytic fuel cell and peroxi-coagulation process affected by iron plate and UV light

Nordin N, Ho LN, Ong SA, Ibrahim AH, Abdul Rani AL, Lee SL, et al.

Chemosphere, 2020 Apr;244:125459.
PMID: 31790991 DOI: 10.1016/j.chemosphere.2019.125459

The hybrid electrochemical system of photocatalytic fuel cell - peroxi-coagulation (PFC-PC) is a combined technology of advanced oxidation process (AOP) which involve the hydroxyl radical formation for simultaneous degradation of organic pollutant and electricity generation. The p-nitrosodimethylaniline (RNO) spin trapping technique was applied by analyzing the RNO bleaching performance to detect the OH at the PFC and PC reactors. The presence of UV light showed higher RNO bleaching rate at the PFC reactor (11.7%) with maximum power density (Pmax = 3.14 mW cm-2). Results revealed that the optimum of maximum power density was observed at iron plate size of 30 cm2. UV light became a limiting factor in the PFC system as a power source in the PFC-PC system. Meanwhile, iron plate plays an important role to supply the soluble Fe2+ ions by oxidation process and become a suitable catalyst for in-situ production of H2O2 and OH through the PC process to degrade the organic molecules.

Matched MeSH terms: Oxidation-Reduction
Oxidative properties of Moringa oleifera kernel oil from different extraction methods during storage

Mat Yusoff M, Niranjan K, Mason OA, Gordon MH

J Sci Food Agric, 2020 Mar 15;100(4):1588-1597.
PMID: 31773733 DOI: 10.1002/jsfa.10167

BACKGROUND: Moringa oleifera (MO) kernel oil is categorized as a high-oleic oil that resembles olive oil. However, unlike olive trees, MO trees are largely present in most subtropical and tropical countries. In these countries, therefore, the benefits of oleic acid can be obtained at a cheaper price through the consumption of MO kernel oil. This study reports on the effect of different extraction methods on oxidative properties of MO kernel oil during storage for 140 days at 13, 25, and 37 °C.
RESULTS: All aqueous enzymatic extraction (AEE)-based methods generally resulted in oil with better oxidative properties and higher tocopherol retention than the use of solvent. Prior to AEE, boiling pre-treatment deactivated the hydrolytic enzymes and preserved the oil's quality. In contrast, high-pressure processing (HPP) pre-treatment accelerated hydrolytic reaction and resulted in an increase in free fatty acids after 140 days at all temperatures. No significant changes were detected in the oils' iodine values and fatty acid composition. The tocopherol content decreased significantly at both 13 and 25 °C after 60 days in the oil from SE method, and after 120 days in oils from AEE-based methods.
CONCLUSION: These findings are significant in highlighting the extraction methods resulting in crude MO kernel oil with greatest oxidative stability in the storage conditions tested. Subsequently, the suitable storage condition of the oil prior to refining can be determined. Further studies are recommended in determining the suitable refining processes and parameters for the MO kernel oil prior to application in variety food products. © 2019 Society of Chemical Industry.

Matched MeSH terms: Oxidation-Reduction
Aberrant Upregulation of Compensatory Redox Molecular Machines May Contribute to Sperm Dysfunction in Infertile Men with Unilateral Varicocele: A Proteomic Insight

Swain N, Samanta L, Agarwal A, Kumar S, Dixit A, Gopalan B, et al.

Antioxid Redox Signal, 2020 03 10;32(8):504-521.
PMID: 31691576 DOI: 10.1089/ars.2019.7828

Aims:
To understand the molecular pathways involved in oxidative stress (OS)-mediated sperm dysfunction against a hypoxic and hyperthermic microenvironment backdrop of varicocele through a proteomic approach.
Results:
Protein selection (261) based on their role in redox homeostasis and/or oxidative/hyperthermic/hypoxic stress response from the sperm proteome data set of unilateral varicocele (UV) in comparison with fertile control displayed 85 to be differentially expressed. Upregulation of cellular oxidant detoxification and glutathione and reduced nicotinamide adenine dinucleotide (NADH) metabolism accompanied with downregulation of protein folding, energy metabolism, and heat stress responses were observed in the UV group. Ingenuity pathway analysis (IPA) predicted suppression of oxidative phosphorylation (OXPHOS) (validated by Western blotting [WB]) along with augmentation in OS and mitochondrial dysfunction in UV. The top affected networks indicated by IPA involved heat shock proteins (HSPs: HSPA2 and HSP90B1). Their expression profile was corroborated by immunocytochemistry and WB. Hypoxia-inducible factor 1A as an upstream regulator of HSPs was predicted by MetaCore. Occurrence of reductive stress in UV spermatozoa was corroborated by thiol redox status.
Innovation:
This is the first evidence of a novel pathway showing aberrant redox homeostasis against chronic hypoxic insult in varicocele leading to sperm dysfunction.
Conclusions:
Upregulation of antioxidant system and dysfunctional OXPHOS would have shifted the redox balance of biological redox couples (GSH/GSSG, NAD+/NADH, and NADP+/NADPH) to a more reducing state leading to reductive stress. Chronic reductive stress-induced OS may be involved in sperm dysfunction in infertile men with UV, where the role of HSPs cannot be ignored. Intervention with antioxidant therapy warrants proper prior investigation.

Matched MeSH terms: Oxidation-Reduction
The microbially driven formation of siderite in salt marsh sediments

Lin CY, Turchyn AV, Krylov A, Antler G

Geobiology, 2020 03;18(2):207-224.
PMID: 31814266 DOI: 10.1111/gbi.12371

We employ complementary field and laboratory-based incubation techniques to explore the geochemical environment where siderite concretions are actively forming and growing, including solid-phase analysis of the sediment, concretion, and associated pore fluid chemistry. These recently formed siderite concretions allow us to explore the geochemical processes that lead to the formation of this less common carbonate mineral. We conclude that there are two phases of siderite concretion growth within the sediment, as there are distinct changes in the carbon isotopic composition and mineralogy across the concretions. Incubated sediment samples allow us to explore the stability of siderite over a range of geochemical conditions. Our incubation results suggest that the formation of siderite can be very rapid (about two weeks or within 400 hr) when there is a substantial source of iron, either from microbial iron reduction or from steel material; however, a source of dissolved iron is not enough to induce siderite precipitation. We suggest that sufficient alkalinity is the limiting factor for siderite precipitation during microbial iron reduction while the lack of dissolved iron is the limiting factor for siderite formation if microbial sulfate reduction is the dominant microbial metabolism. We show that siderite can form via heated transformation (at temperature 100°C for 48 hr) of calcite and monohydrocalcite seeds in the presence of dissolved iron. Our transformation experiments suggest that the formation of siderite is promoted when carbonate seeds are present.

Matched MeSH terms: Oxidation-Reduction
Quantitation of Protein Cysteine-Phenol Adducts in Minced Beef Containing 4-Methyl Catechol

Arsad SS, Zainudin MAM, De Gobba C, Jongberg S, Larsen FH, Lametsch R, et al.

J Agric Food Chem, 2020 Feb 26;68(8):2506-2515.
PMID: 32013414 DOI: 10.1021/acs.jafc.9b07752

Thiol groups of cysteine (Cys) residues in proteins react with quinones, oxidation products of polyphenols, to form protein-polyphenol adducts. The aim of the present work was to quantify the amount of adduct formed between Cys residues and 4-methylcatechol (4MC) in minced beef. A Cys-4MC adduct standard was electrochemically synthesized and characterized by liquid chromatography-mass spectrometry (LC-MS) as well as NMR spectroscopy. Cys-4MC adducts were quantified after acidic hydrolysis of myofibrillar protein isolates (MPIs) and LC-MS/MS analysis of meat containing either 500 or 1500 ppm 4MC and stored at 4 °C for 7 days under a nitrogen or oxygen atmosphere. The concentrations of Cys-4MC were found to be 2.2 ± 0.3 nmol/mg MPI and 8.1 ± 0.9 nmol/mg MPI in meat containing 500 and 1500 ppm 4MC, respectively, and stored for 7 days under oxygen. The formation of the Cys-4MC adduct resulted in protein thiol loss, and ca. 62% of the thiol loss was estimated to account for the formation of the Cys-4MC adduct for meat containing 1500 ppm 4MC. Furthermore, protein polymerization increased in samples containing 4MC as evaluated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and the polymerization was found to originate from protein-polyphenol interactions as evaluated by a blotting assay with staining by nitroblue tetrazolium.

Matched MeSH terms: Oxidation-Reduction
Fulltext Effect of Hybrid mono/bimetallic Nanocomposites for an enhancement of Catalytic and Antimicrobial Activities

Sivaranjan K, Padmaraj O, Santhanalakshmi J, Sathuvan M, Sathiyaseelan A, Sagadevan S

Sci Rep, 2020 02 13;10(1):2586.
PMID: 32054936 DOI: 10.1038/s41598-020-59491-5

Exploring the new catalytic systems for the reduction of organic and inorganic pollutants from an indispensable process in chemical, petrochemical, pharmaceutical and food industries, etc. Hence, in the present work, authors motivated to synthesize bare reduced graphene oxide (rGO), polyaniline (PANI), three different ratios of rGO-PANI(80:20,50:50, 10:90) composites and rGO-PANI(80:20,50:50, 10:90) supported mono (Pd) & bimetallic [Pd: Au(1:1,1:2, 2:1)] nanocomposite by a facile chemical reduction method. Also, it investigated their catalytic performances for the reduction of organic/inorganic pollutants and antimicrobial activities. All the freshly prepared bare rGO, PANI, three different ratios of rGO-PANI(80:20, 50:50,10:90) composites and rGO-PANI(80:20, 50:50,10:90)/Pd & Pd: Au(1:1, 1:2,2:1) nanocomposite hybrid catalysts were characterized using UV-Vis, FT-IR, SEM, FE-SEM, EDAX, HR-TEM, XRD, XPS and Raman spectroscopy analysis. Among them, an optimized best composition of rGO-PANI(80:20)/Pd: Au(1:1) bimetallic nanocomposite hybrid catalyst exhibits better catalytic reduction and antimicrobial activities than other composites, as a result of strong electrostatic interactions between rGO, PANI and bimetal (Pd: Au) NPs through a synergistic effect. Hence, an optimized rGO-PANI(80:20)/Pd:Au(1:1) bimetallic nanocomposite catalyst would be considered as a suitable catalyst for the reduction of different nitroarenes, organic dyes, heavy metal ions and also significantly inhibit the growth of S. aureus, S. Typhi as well as Candida albicans and Candida kruesi in wastewater.

Matched MeSH terms: Oxidation-Reduction
Effect of aquaculture salinity on nitrification and microbial community in moving bed bioreactors with immobilized microbial granules

Gao Y, Wang X, Li J, Lee CT, Ong PY, Zhang Z, et al.

Bioresour Technol, 2020 Feb;297:122427.
PMID: 31784249 DOI: 10.1016/j.biortech.2019.122427

The novel immobilized microbial granules (IMG) shows a significant effect of nitrification for freshwater aquaculture. However, there is lack of evaluation study on the performance of nitrification at high salinity due to the concentration of recycled water or seawater utilization. A laboratory scale moving bed bioreactor (MBBR) with IMG was tested on recycled synthetic aquaculture wastewater for the nitrification at 2.5 mg/L NH3-N daily. The results indicated that IMG showed a high salinity tolerance and effectively converted ammonia to nitrate up to 92% at high salinity of 35.0 g/L NaCl. As salinity increased from near zero to 35.0 g/L, the microbial activity of nitrite oxidation bacteria (NOB) in the IMG decreased by 86.32%. The microbial community analysis indicated that salinity significantly influenced the community structure. It was found that Nitrosomonas sp. and Nitrospira sp. were the dominant genera for ammonia oxidation bacteria (AOB) and NOB respectively at different salinity levels.

Matched MeSH terms: Oxidation-Reduction
Effect of rice bran oil addition on the oxidative degradation and fatty acid composition of soybean oil during heating

Ali MA, Islam MA, Othman NH, Noor AM, Ibrahim M

Acta Sci Pol Technol Aliment, 2020 1 14;18(4):427-438.
PMID: 31930793 DOI: 10.17306/J.AFS.0694

BACKGROUND: Rice bran oil (RBO) contains significant amounts of micronutrients (oryzanol, tocotrienol, tocopherol, phytosterols etc.) that impart a high resistance to thermal oxidation of the oil. The high oxidative stability of RBO can make it a preferred oil to improve the oxidative and flavor stabilities of other oils rich in PUFAs. In this study, the changes in the oxidative status and fatty acid composition in soybean oil (SO) blended with RBO under extreme thermal conditions were evaluated.
METHODS: The blends were prepared in a volume ratio of 10:90, 20:80, 40:60, and 60:40 (RBO:SO). The changes in the oxidative parameters and fatty acid composition of the samples during heating at frying temperature (170°C) were determined using analytical and instrumental methods. Oxidative alteration was also monitored by recording FTIR spectra of oil samples.
RESULTS: The increase in oxidative parameters (free fatty acid, color, specific extinctions, peroxide value, p-anisidine value, and thiobarbituric acid value) was greater in pure SO as compared to RBO or blend oils during heating. This indicates that the SO samples incorporated with RBO have the least degradation, while pure SO has the highest. Blending resulted in a lower level of polyunsaturated fatty acids (PUFA) with a higher level of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA). During heating, the relative content of PUFA decreased and that of SFA increased. However, the presence of RBO in SO slowed down the oxidative deterioration of PUFA. In FTIR, the peak intensities in SO were markedly changed in comparison with blend oils during heating. The reduction in the formation of oxidative products in SO during thermal treatment increased as the concentration of the RBO in SO increased; however, the levels of the protective effect of RBO did not increase steadily with an increase in its concentration.
CONCLUSIONS: During thermal treatment, the generation of hydroperoxides, their degradation and formation of secondary oxidative products as evaluated by oxidative indices, fatty acids and IR absorbances were lower in blend oils compared to pure SO. In conclusion, RBO can significantly retard the process of lipid peroxidation in SO during heating at frying temperature.

Matched MeSH terms: Oxidation-Reduction
Effect of storage conditions on maintaining anammox cell viability during starvation and recovery

Ganesan S, Vadivelu VM

Bioresour Technol, 2020 Jan;296:122341.
PMID: 31711905 DOI: 10.1016/j.biortech.2019.122341

Anammox bacteria can easily undergo starvation due to fluctuations in feed flowrate and concentration in wastewater treatment plants. In this study, we analyzed the effects of different types of storage conditions (presence of ammonium (Ra), nitrite (Rn), hydrazine (Rh), and no substrate (Rc)) in aiding the viability of anammox bacteria during starvation and recovery. After starvation, the bacteria were subjected to a 15-week recovery period. Anammox bacteria showed better results during starvation and recovery in Rh as compared to other conditions. Decay rate values obtained after starvation in Ra, Rn, Rh, and Rc were 0.032/day, 0.042/day, 0.019/day, and 0.037/day, respectively. Meanwhile, µmax values obtained in Rh, Ra, Rn, and Rc on the 15th week of recovery were 0.092, 0.075, 0.011, and 0.067 d-1, respectively. This indicated that the availability of hydrazine helps to reduce the mortality rate of anammox bacteria during starvation and enhances the recovery of anammox process.

Matched MeSH terms: Oxidation-Reduction
Fulltext Optimisation of an electrochemical sensor based on bare gold electrode for detection of aluminium ion

Gilbert Ringgit, Shafiquzzaman Siddiquee, Suryani Saallah, Mohammad Tamrin Mohamad Lal

Borneo International Journal of Biotechnology, 2020;1(1):103-123.
MyJurnal

In this work, an electrochemical method for detection of trace amount of aluminium (Al3+), a heavy metal ion, based on a bare gold electrode (AuE) was developed. Current responses of the AuE under various type of electrolytes, redox indicators, pH, scan rate and accumulation time were investigated using cyclic voltammetry (CV) method to obtain the optimum conditions for Al3+ detection. The sensing properties of the AuE towards the target ion with different concentrations were investigated using differential pulse voltammetry (DPV) method. From the CV results, the optimal conditions for the detection of Al3+ were Tris-HCl buffer (0.1 M, pH 2) supported by 5 mM Prussian blue with scan rate and accumulation time respectively of 100 mVs−1 and 15 s. Under the optimum conditions, the DPV method was detected with different concentrations of aluminium ion ranging from 0.2 to 1.0 ppm resulted in a good linear regression r² = 0.9806. This result suggests that the optimisation of the basic parameters in electrochemical detection using AuE is crucial before further modification of the Au-electrode to improve the sensitivity and selectivity especially for the low concentration of ion detection. The developed method has a great potential for rapid detection of heavy metal ion (Al3+) in drinking water samples.

Matched MeSH terms: Oxidation-Reduction

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