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Journal articles on the topic 'Oxidising enzymes'
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1
Gorton, Lo. "Special issue on sugar oxidising enzymes." Bioelectrochemistry 135 (October 2020): 107577. http://dx.doi.org/10.1016/j.bioelechem.2020.107577.
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Urbanska, Anna, W. Freddy Tjallingii, Anthony F. G. Dixon, and Bogumil Leszczynski. "Phenol oxidising enzymes in the grain aphid's saliva." Entomologia Experimentalis et Applicata 86, no. 2 (February 1998): 197–203. http://dx.doi.org/10.1046/j.1570-7458.1998.00281.x.
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Wang, Ting, Liang Liang Wang, and Xun Li. "Cloning, Expression and Characterization of a Monooxygenase P450BM3 from Bacillus megaterium ALA2." Advanced Materials Research 518-523 (May 2012): 5533–38. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.5533.
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Cytochrome P450 monooxygenases are enzymes which are capable of oxidising saturated and unsaturated substrates. P450BM3 from Bacillus megaterium is one of this family. For the first time, the cyp gene for coding P450BM3 from B. megaterium ALA2 has been cloned and expressed in Escherichia coli. The recombinant enzyme is 120 kDa, containing 1049 aa. The highest activity of purified enzyme is 14.8 U/mg towards palmitic acid by monitoring the NADPH oxidation. The optimal pH and temperature were 9.0 and 40°C. The enzyme has higher activity towards linoleic acid, and 2-Methyl-7-octadecene can also be catalyzed which is a precursor of displar.
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Wagenführ, André, Sören Tech, and Holger Unbehaun. "Modifizierung der Holzeigenschaften durch Enzyme | Modification of wood properties through enzymes." Schweizerische Zeitschrift fur Forstwesen 156, no. 11 (November 1, 2005): 420–26. http://dx.doi.org/10.3188/szf.2005.0420.
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The addition of phenol oxidising enzyme preparations leads to a change in the fibre structure of lignocellulose products. This means that positive material properties can be selectively put in. In the production of materials the use of activated ownfibre binding forces only makes sense when the production process ensures that fibres are as close to one another as possible. This can be accomplished by fine tuning the density of the material to the method in question. Material densities of over 600 kg/m3 are necessary for dry method approaches. With wet methods, on the other hand, the properties of material can be improved starting from a density of 160 kg/m3. A good distribution and the use of additionally created hydro-bridge builders are responsible for this. The employment of charge carriers during the processing with a wet method also has a positive influence on the physical properties. The suspended particles that become detached from the fibre in the process bind together and are concentrated on the surface of the fibre. To improve the steering of the process with the wet method further enzymatic treatment steps in lignocellulose can be carried out with micro- and nano-particle systems. This can be done via combinations of cationic starch or cationic polyacrylamide. With these systems the cationic polymer is added to the fibre suspension first, followed by the micro-particle components. Both the levels of additives used and the required incubation times can thereby be markedly reduced. Here for the first time we succeeded in using enzymes in processing technically relevant dimensions and were therefore able to renounce the addition of synthetic binding means without impairing the properties of the material.
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Pillay, C. S., and C. Dennison. "Cathepsin B Stability, But Not Activity, Is Affected in Cysteine:Cystine Redox Buffers." Biological Chemistry 383, no. 7-8 (August 27, 2002): 1199–204. http://dx.doi.org/10.1515/bc.2002.132.
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Abstract In order to test the hypothesis that the lysosomal cysteine protease cathepsin B may be redox regulated in vivo, cathepsin B activity and stability were measured in cysteine and/or cystinecontaining buffers. Cathepsin B activity in cysteinecontaining buffers was similar at pH 6.0 and pH 7.0, over all thiol concentrations tested. In contrast, the stability of the enzyme was greater at pH 6.0 than at pH 7.0. This suggests that the enzymes operational pH in vivo may be < pH 7.0. The activity of the enzyme was depressed in glutathionecontaining buffers. When assessed in cysteine:cystine redox buffers (pH 6.0 7.0) cathepsin B was active over a broad redox potential range, suggesting that cathepsin B activity may not be redox regulated. However, at pH 7.0, the stability of cathepsin B decreased with increasing reduction potential and ambient cystine concentration. This suggests that the stability of the enzyme at neutral pH is dependent on redox potential, and on the presence of oxidising agents.
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MacAodha, Domhnall, Peter Ó Conghaile, Brenda Egan, Paul Kavanagh, Christoph Sygmund, Roland Ludwig, and Dónal Leech. "Comparison of Glucose Oxidation by Crosslinked Redox Polymer Enzyme Electrodes Containing Carbon Nanotubes and a Range of Glucose Oxidising Enzymes." Electroanalysis 25, no. 1 (December 5, 2012): 94–100. http://dx.doi.org/10.1002/elan.201200536.
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Iftikhar, Mehwish, Lin Wang, and Zhijie Fang. "Synthesis of 1-Deoxynojirimycin: Exploration of Optimised Conditions for Reductive Amidation and Separation of Epimers." Journal of Chemical Research 41, no. 8 (August 2017): 460–64. http://dx.doi.org/10.3184/174751917x15000341607489.
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1-Deoxynojirimycin (DNJ), which has importance with respect to sugar processing enzymes, is a synthetic target for chemists. A key step in the synthesis of DNJ is the preparation of 2,3,4,6-tetra- O-benzyl-D-glucono-δ-lactam. By varying reaction parameters such as temperature, solvent and reducing reagent, improvements on previous methods are described. A novel approach for the synthesis of 2,3,4,6-tetra- O-benzyl-5-dehydro-5-deoxo-D-gluconamide has been developed by using PCC as an oxidising agent. Separation of epimers permitted DNJ to be obtained in 85% yield after reduction and hydrogenolysis steps.
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Chauhan, P. K., Rishma ., V. Singh, and Abhishek B. "Comparaative study of Lipid profile and level of Antioxidant enzymes in cigarette smokers with non cigaretee smokers." Indian Journal of Pharmaceutical and Biological Research 1, no. 01 (January 31, 2013): 55–62. http://dx.doi.org/10.30750/ijpbr.1.1.5.
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Cigarette smoking is the serious health problems and most important avoidable cause of death in world. Worldwide more than 8 million people currently die each year from smoking half of them before of the age of 60. Every cigarette reduces the life span by about 5 minutes. Smoke contains oxidising agents and the oxidation reactions can produce free radicals. In turn, these radicals can start chain reactions that damage cells. In the present study 40 male subjects were divided into four different groups and their lipid profile have been estimated by various tests i.e. Cholesterol, Triglyceride, HDL-C, LDLC, VLDL-C. It was observed that in cigarette smokers HDL-C level decreased and cholesterol, triglyceride, LDL-C, VLDL-C level increased as compared to the control i.e. non- cigarette smokers. In case of MDA and Antioxidant enzymes test, the value of MDA increases and antioxidant enzymes decreases in cigarette smokers as compared to the control i.e. non- cigarette smokers. The variation in the level of lipid profile and antioxidant enzymes from normal values causes several diseases such as Lung cancer, other cancers, heart disease, and stroke and has numerous immediate health effects on the brain and on the respiratory, cardiovascular, gastrointestinal, immune systems.
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Rajashekar, N., and T. C. Shivashankara Murthy. "Toxicological aspects of pendimethalin induced activities of certain oxidising and hydrolytic enzymes in the germinating seedlings of maize (Zea maysL.)." Archives Of Phytopathology And Plant Protection 43, no. 3 (February 2010): 296–301. http://dx.doi.org/10.1080/03235400701804018.
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Tsuchiya, Yugo, Sew Yeu Peak-Chew, Clare Newell, Sheritta Miller-Aidoo, Sriyash Mangal, Alexander Zhyvoloup, Jovana Bakovic´, et al. "Protein CoAlation: a redox-regulated protein modification by coenzyme A in mammalian cells." Biochemical Journal 474, no. 14 (July 11, 2017): 2489–508. http://dx.doi.org/10.1042/bcj20170129.
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Coenzyme A (CoA) is an obligatory cofactor in all branches of life. CoA and its derivatives are involved in major metabolic pathways, allosteric interactions and the regulation of gene expression. Abnormal biosynthesis and homeostasis of CoA and its derivatives have been associated with various human pathologies, including cancer, diabetes and neurodegeneration. Using an anti-CoA monoclonal antibody and mass spectrometry, we identified a wide range of cellular proteins which are modified by covalent attachment of CoA to cysteine thiols (CoAlation). We show that protein CoAlation is a reversible post-translational modification that is induced in mammalian cells and tissues by oxidising agents and metabolic stress. Many key cellular enzymes were found to be CoAlated in vitro and in vivo in ways that modified their activities. Our study reveals that protein CoAlation is a widespread post-translational modification which may play an important role in redox regulation under physiological and pathophysiological conditions.
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Lennicke, Claudia, and Helena M. Cochemé. "Redox signalling and ageing: insights from Drosophila." Biochemical Society Transactions 48, no. 2 (March 20, 2020): 367–77. http://dx.doi.org/10.1042/bst20190052.
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Ageing and age-related diseases are major challenges for the social, economic and healthcare systems of our society. Amongst many theories, reactive oxygen species (ROS) have been implicated as a driver of the ageing process. As by-products of aerobic metabolism, ROS are able to randomly oxidise macromolecules, causing intracellular damage that accumulates over time and ultimately leads to dysfunction and cell death. However, the genetic overexpression of enzymes involved in the detoxification of ROS or treatment with antioxidants did not generally extend lifespan, prompting a re-evaluation of the causal role for ROS in ageing. More recently, ROS have emerged as key players in normal cellular signalling by oxidising redox-sensitive cysteine residues within proteins. Therefore, while high levels of ROS may be harmful and induce oxidative stress, low levels of ROS may actually be beneficial as mediators of redox signalling. In this context, enhancing ROS production in model organisms can extend lifespan, with biological effects dependent on the site, levels, and specific species of ROS. In this review, we examine the role of ROS in ageing, with a particular focus on the importance of the fruit fly Drosophila as a powerful model system to study redox processes in vivo.
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Żółciak, Anna. "Determination of Pleurotus abieticola ligninolytic activity on Norway spruce wood." Folia Forestalia Polonica 61, no. 4 (December 1, 2019): 267–77. http://dx.doi.org/10.2478/ffp-2019-0026.
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Abstract The effect of Phlebiopsis gigantea treatment in control of Heterobasidion parviporum in Norway spruce is less effective than that in control of Heterobasidion annosum in pine. It is necessary to apply other fungi, for example, Pleurotus abieticola in Norway spruce stands. Thus, it is necessary to assess the activity of major ligninolytic enzymes, that is, laccase, lignin peroxidase (LiP), manganese peroxidase (MnP) and versatile peroxidase (VP) produced by P. abieticola, which may be effective in the fast degradation of Norway spruce wood. Three strains of P. abieticola (Pa1-3) were grown on pieces of Norway spruce sapwood and heartwood for 50 days in laboratory conditions. Enzymatic activity was determined using spectrophotometry. Pleurotus abieticola produced laccase, LiP, MnP and VP. The activity of laccase was low, ranging 0–3.696 and 0–0.806 mU/μg of protein in sapwood and heartwood, respectively. The highest activity in Pa1 = 3.696 mU/μg of protein in sapwood and in Pa3 = 0.806 mU/μg of protein in heartwood was observed after 30 and 50 days of incubation, respectively. The activity of LiP was also low, ranging 0–0.188 and 0–0.271 mU/μg of protein in sapwood and heartwood, respectively. The highest activity in Pa1 = 0.271 mU/μg of protein in sapwood and in Pa2 = 0.188 mU/μg of protein in heartwood was observed after 40 and 20 days of incubation, respectively. The activity of MnP ranged 0–17.618 and 0–12.203 mU/μg of protein in sapwood and heartwood, respectively. This enzymatic activity peaked at the 50th day of culture on sapwood for the Pa3 strain (17.618 mU/μg of protein) and at the 20th day of culture on heartwood for the Pa1 strain (12.203 mU/μg of protein). The activity of VP with manganese-oxidising properties was found to be high in all strains of P. abieticola, ranging 0–39.19 and 0–59.153 mU/μg of protein in sapwood and heartwood, respectively, whereas the activity of VP with guaiacol-oxidising properties was very low for all P. abieticola strains, ranging 0–0.248 and 0–0.225 mU/μg of protein in sapwood and heartwood, respectively. The values of released hydroxyphenols in P. abieticola strains ranged 24.915–139.766 and 25.19–84.562 µg of protocatechuic acid/ml in sapwood and heartwood, respectively. The values of released methoxyphenols for the evaluated strains of P. abieticola ranged 7.225–23.789 and 1.953–20.651 µg of vanillic acid/ml in sapwood and heartwood, respectively. Further studies with a higher number of strains of this species as well as an optimisation of conditions for the measurement of ligninolytic activity are needed.
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Bruhn, Dan, Joseph T. Wiskich, and Owen K. Atkin. "Contrasting responses by respiration to elevated CO2 in intact tissue and isolated mitochondria." Functional Plant Biology 34, no. 2 (2007): 112. http://dx.doi.org/10.1071/fp06247.
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The question of whether elevated concentrations of CO2 directly inhibit mitochondrial respiration in plants has received considerable attention. Although there is a growing consensus that elevated [CO2] rarely inhibits respiration of intact tissues, past studies have reported that elevated [CO2] does impact on O2 uptake in isolated mitochondria; what remains unclear, however, is the site(s) where elevated [CO2] impacts on mitochondrial electron transport (ETC). Here we investigated direct effects of [CO2] on respiratory activity of ETC enzymes, intact mitochondria and whole tissues using potato tubers (Solanum tuberosum L. cv. Desiree). Plots of O2 uptake against the redox poise of the ubiquinone (UQ) pool in isolated mitochondria were used to determine whether elevated [CO2] inhibits UQ-reducing and UQ-oxidising pathways differentially. Our results show that mitochondrial respiration was more inhibited via [CO2]/[HCO3–] effects on cytochrome c oxidase (COX) than on succinate dehydrogenase, with [HCO3–] rather than [CO2] inhibiting COX. However, the inhibitory effects at the mitochondrial level did not translate into inhibitory effects at the tissue level. Alternative oxidase (AOX) activity is normally absent in young potato tubers, as was the case in the present study. Thus, the lack of CO2-mediated inhibition at the tissue level was not the result of increases in AOX activity masking the effects of CO2 elsewhere in the respiratory system. We discuss whether the direct impact of elevated [CO2] on respiration is dependent on the rate of metabolic activity and flux control coefficients in individual tissues.
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Gürke, J., E. Haucke, R. Thieme, F. Hirche, M. Schindler, B. Fischer, and A. Navarrete Santos. "95 ALTERED PROTEIN AND AMINO-ACID METABOLISM IN PREIMPLANTATION EMBRYOS FROM DIABETIC RABBITS." Reproduction, Fertility and Development 25, no. 1 (2013): 195. http://dx.doi.org/10.1071/rdv25n1ab95.
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During pregnancy the preimplantation period is a critical ontogenetic stage in embryo development. As the embryo is highly sensitive to its surrounding milieu and vulnerable to dysregulations by external stimuli, we investigated the influence of a maternal diabetes mellitus type 1 on blastocyst metabolism and protein modifications. Here we report on protein and amino acid metabolism in preimplantation embryos. A diabetes mellitus type 1 rabbit model was used to measure the protein and amino acid concentrations in blastocyst cavity fluid at Day 6 postcoitum. The protein concentration was enhanced in embryos from diabetic rabbits. The level of the various proteinogenic amino acids was unchanged except for the branched-chain amino acids (BCAAs; l-leucine, l-isoleucine, l-valine). The concentration of l-leucine [153.9 µM ± 60.14] and l-valine [231.95 µM ± 75.67] increased 2-fold and of l-isoleucine [99.85 µM ± 42.92] increased 3-fold. Due to the altered BCAA levels, we assumed a disturbed biodegradation. The expression of the BCAA oxidising enzymes (Bcat2, Bckdha, Dbt, and Dld) and BCAA transporters was determined by real-time PCR. Embryos grown in diabetic rabbits revealed a decreased expression of BCAA oxidizing enzymes and of the BCAA transporter LAT-2. The BCAA transporter LAT-2 was mainly localized in the embryoblast. The quality of proteins in blastocysts from diabetic rabbits was evaluated by analyzing protein glycation (advanced glycation end products, AGEs). Two specific AGE modifications, namely arg-pyrimidine and pentosidine, were detected in Day-6 blastocysts by Western Blot analysis. In blastocyst cavity fluid the AGE-specific fluorescence at 440ex/535em nm was significantly enhanced. Our findings show that not just the quantity of proteins but also the quality is affected in rabbit embryos grown in diabetic mothers. There is evidence to suggest that vital protein interactions and signalling pathways are misprogrammed with likely negative consequences for further life. Supported by EU FP 7 EpiHealth (N°278418).
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Wijffels, Gene, Megan Sullivan, Stephen Anderson, Sally Stockwell, Suzie Briscoe, Russell McCulloch, Judy Cawdell-Smith, and John Gaughan. "Metabolism and Endocrinology of Cattle in High Environmental Temperatures." Proceedings 36, no. 1 (April 10, 2020): 211. http://dx.doi.org/10.3390/proceedings2019036211.
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Close-to-market weight grain fed cattle experience high heat loads during summer. There are health, welfare and production impacts on these high value animals. Two cohorts of 600 kg Black Angus steers (n = 12) were subjected to heatwave conditions during a thermal challenge in climate chambers. Frequent blood sampling enabled a detailed description of the metabolic and endocrine trajectories during high heat load and recovery in feedlot cattle. In high heat load ruminants, blood flow is diverted from the major organs impacting metabolic rate and cellular functions. The metabolic rate will slow with falls in the thyroid hormone plasma concentrations. Insulin and the adipokines gave an indifferent response. The high heat load cattle were hypoglycaemic and oxidising fatty acids. Liver involvement was evidenced by the build-up of bilirubin in plasma, and reduced release of cholesterol and ALP. Thermal challenge saw markedly increased plasma creatinine and urea implicating reduced glomerular filtration; although the kidneys were working to retain chloride ions to balance the loss of bicarbonate from the increased respiration rate. As heat load reduced during recovery, rumen temperature and respiration rate normalised and feed intake gradually returned. Plasma glucose levels increased also. With increased blood supply to the organs, there was a rise in liver enzymes into the blood, although liver function had not fully restored during the recovery period; plasma bilirubin concentrations were still high, and ALP and cholesterol levels low. Twelve days after the thermal challenge, most blood parameters had returned to normal and the steers had gained weight.
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Awasthi, Rashmi, Neeru Kaushal, Vincent Vadez, Neil C. Turner, Jens Berger, Kadambot H. M. Siddique, and Harsh Nayyar. "Individual and combined effects of transient drought and heat stress on carbon assimilation and seed filling in chickpea." Functional Plant Biology 41, no. 11 (2014): 1148. http://dx.doi.org/10.1071/fp13340.
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High temperatures and decreased rainfall are detrimental to yield in chickpea (Cicer arietinum L.), particularly during grain filling. This study aimed to (i) assess the individual and combined effects of drought and heat stress on biochemical seed-filling processes, (ii) determine genotypic differences in heat and drought tolerance, and (iii) determine any cross-tolerance. Plants were grown outdoors in the normal growing season when temperatures during seed filling were <32−20°C or were planted late (temperatures >32−20°C; heat stress). Half of the pots were kept adequately watered throughout, but water was withheld from the others from the initiation of seed filling until the relative leaf water content reached 50% of the irrigated plants (drought stress); all plants were rewatered thereafter until seed maturit. Water was withheld for 13 days (normal sowing) and 7 days (late sowing), so soil moisture decreased by 54–57%. Tests on leaves and seeds were performed after the stress. Individual and combined stress damaged membranes, and decreased cellular oxidising ability, stomatal conductance, PSII function and leaf chlorophyll content; damage was greater under combined stress. Leaf Rubisco activity increased with heat stress, decreased with drought stress and decreased severely with combined stress. Sucrose and starch concentrations decreased in all seeds through reductions in biosynthetic enzymes; reductions were greater under combined stress. These effects were more severe in heat- and drought-sensitive genotypes compared with drought-tolerant genotypes. Drought stress had a greater effect than heat stress on yield and the biochemical seed-filling mechanisms. Drought- and heat-tolerant genotypes showed partial cross-tolerance.
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SHARMA, Rajesh K., Brian G. LAKE, Richard MAKOWSKI, Tony BRADSHAW, Dave EARNSHAW, Jeremy W. DALE, and G. Gordon GIBSON. "Differential induction of peroxisomal and microsomal fatty-acid-oxidising enzymes by peroxisome proliferators in rat liver and kidney. Characterisation of a renal cytochrome P-450 and implications for peroxisome proliferation." European Journal of Biochemistry 184, no. 1 (September 1989): 69–78. http://dx.doi.org/10.1111/j.1432-1033.1989.tb14991.x.
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Zhu, Yinuo, Jing Li, Zhangjie Cai, Wei Li, Yinru Lei, Manyin Zhang, and Lijuan Cui. "Relationships between nitrogen removal processes and functional microorganisms in the rhizosphere soil in a horizontal surface flow constructed wetland." Marine and Freshwater Research 70, no. 11 (2019): 1603. http://dx.doi.org/10.1071/mf19033.
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Plant species could significantly affect the nitrogen removal processes mediated by microorganisms in constructed wetlands. However, the links between nitrogen removal processes in the rhizosphere and the related functional microorganisms in a horizontal surface flow constructed wetland in winter remain poorly understood. In this study we collected 24 rhizosphere soils from Typha orientalis and Phragmites australis to evaluate potential nitrogen removal activities, namely the potential nitrification rate (PNR) and denitrification enzyme activity (DEA), and their relationship with functional genes (i.e. nitrate reductase, nirS, and ammonia mono-oxygenase, amoA, of ammonia-oxidising archaea, AOA, and ammonia-oxidising bacteria, AOB) in denitrifiers and nitrifiers in winter. DEA and PNR were significantly higher in the rhizosphere soil of T. orientalis than P. australis, which was due to the higher abundance of nitrifiers and denitrifiers in the rhizosphere of T. orientalis. AOB were the major predictor of PNR in rhizosphere soil of T. orientalis, whereas AOA were more important for P. australis. In addition, denitrifiers containing the nirS gene were found to be the main drivers of DEA, and AOA and AOB also contributed to the denitrification process in the rhizosphere soil of both plants. Furthermore, the abundance of nitrifiers was significantly affected by the C:N ratio, soil organic matter and moisture, whereas the abundance of denitrifiers was affected by soil moisture and pH.
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Lia, Andrea, Adam Dowle, Chris Taylor, Angelo Santino, and Pietro Roversi. "Partial catalytic Cys oxidation of human GAPDH." Wellcome Open Research 5 (June 1, 2020): 114. http://dx.doi.org/10.12688/wellcomeopenres.15893.1.
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Background: n-Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) catalyses the reversible NAD+-dependent oxidative phosphorylation of n-glyceraldehyde-3-phosphate to 1,3-diphospho-n-glycerate in both glycolysis and gluconeogenesis. Methods: Four distinct crystal structures of human n-Glyceraldehyde-3-phosphate dehydrogenase (HsGAPDH) have been determined from protein purified from the supernatant of HEK293F human epithelial kidney cells. Results: X-ray crystallography and mass-spectrometry indicate that the catalytic cysteine of the protein (HsGAPDH Cys152) is partially oxidised to cysteine S-sulfonic acid. The average occupancy for the Cys152-S-sulfonic acid modification over the 20 crystallographically independent copies of HsGAPDH across three of the crystal forms obtained is 0.31±0.17. Conclusions: The modification induces no significant structural changes on the tetrameric enzyme, and only makes aspecific contacts to surface residues in the active site, in keeping with the hypothesis that the oxidising conditions of the secreted mammalian cell expression system result in HsGAPDH catalytic cysteine S-sulfonic acid modification and irreversible inactivation of the enzyme.
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Lia, Andrea, Adam Dowle, Chris Taylor, Angelo Santino, and Pietro Roversi. "Partial catalytic Cys oxidation of human GAPDH to Cys-sulfonic acid." Wellcome Open Research 5 (August 25, 2020): 114. http://dx.doi.org/10.12688/wellcomeopenres.15893.2.
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Background: n-Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) catalyses the NAD+-dependent oxidative phosphorylation of n-glyceraldehyde-3-phosphate to 1,3-diphospho-n-glycerate and its reverse reaction in glycolysis and gluconeogenesis. Methods: Four distinct crystal structures of human n-Glyceraldehyde-3-phosphate dehydrogenase (HsGAPDH) have been determined from protein purified from the supernatant of HEK293F human epithelial kidney cells. Results: X-ray crystallography and mass-spectrometry indicate that the catalytic cysteine of the protein (HsGAPDH Cys152) is partially oxidised to cysteine S-sulfonic acid. The average occupancy for the Cys152-S-sulfonic acid modification over the 20 crystallographically independent copies of HsGAPDH across three of the crystal forms obtained is 0.31±0.17. Conclusions: The modification induces no significant structural changes on the tetrameric enzyme, and only makes aspecific contacts to surface residues in the active site, in keeping with the hypothesis that the oxidising conditions of the secreted mammalian cell expression system result in HsGAPDH catalytic cysteine S-sulfonic acid modification and irreversible inactivation of the enzyme.
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Kavanagh, Paul, and Dónal Leech. "Mediated electron transfer in glucose oxidising enzyme electrodes for application to biofuel cells: recent progress and perspectives." Physical Chemistry Chemical Physics 15, no. 14 (2013): 4859. http://dx.doi.org/10.1039/c3cp44617d.
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O'Sullivan, Cathryn A., Steven A. Wakelin, Ian R. P. Fillery, and Margaret M. Roper. "Factors affecting ammonia-oxidising microorganisms and potential nitrification rates in southern Australian agricultural soils." Soil Research 51, no. 3 (2013): 240. http://dx.doi.org/10.1071/sr13039.
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Ammonia-oxidising archaea (AOA) have recently been described as having an important role in soil nitrification. However, published data on factors which influence their distribution and their impact on a soil’s potential nitrification rates (PNR) are sparse, particularly compared with the amount of information available regarding ammonia-oxidising bacteria (AOB). This study had two aims. First, to investigate which environmental factors affect the AOA : AOB ratio in soils from two agricultural regions, and second, to explore whether the abundance of either AOA or AOB correlated with PNR. Samples were collected from 45 sites within the cropping regions of Western Australia and South Australia. Soils were tested for pH, NH4+/NO3–, organic carbon (C), total nitrogen (N), C : N ratio, PNR, and electrical conductivity. Climate data were obtained from the Queensland Climate Change Centre for Excellence SILO website. Abundances of AOA and AOB were measured using real-time PCR quantification of the gene encoding the ammonia monooxygenase enzyme (amoA). Multivariate statistical analysis was applied to assess correlations between PNR, soil properties, and abundance of AOA or AOB. In the majority samples AOA were present, but their abundance, and the AOA : AOB ratio, varied considerably between sites. Multivariate analysis showed that the distribution of AOA and AOB and the AOA : AOB ratio were strongly correlated with climatic and seasonal factors. Sites where samples were collected during dry, hot periods tended to be AOA-dominated, whereas samples collected during cool, wet periods tended to be AOB-dominated or have equal abundances of AOA and AOB. The PNRs were correlated with total N content, organic C content, and soil pH. There was no clear correlation between AOA or AOB and PNR. This study shows that both AOA and AOB are widespread in Western Australian and South Australian soils and their abundance and ratio are affected by climate and season. It also shows that PNR is more strongly influenced by soil fertility factors than by the AOA : AOB ratio.
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Rapson, Trevor D., Ulrike Kappler, Graeme R. Hanson, and Paul V. Bernhardt. "Short circuiting a sulfite oxidising enzyme with direct electrochemistry: Active site substitutions and their effect on catalysis and electron transfer." Biochimica et Biophysica Acta (BBA) - Bioenergetics 1807, no. 1 (January 2011): 108–18. http://dx.doi.org/10.1016/j.bbabio.2010.09.005.
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Janosch, Claudia, Christian Thyssen, Mario A. Vera, Violaine Bonnefoy, Thore Rohwerder, and Wolfgang Sand. "Sulfur Oxygenase Reductase in Different Acidithiobacillus Caldus-Like Strains." Advanced Materials Research 71-73 (May 2009): 239–42. http://dx.doi.org/10.4028/www.scientific.net/amr.71-73.239.
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The elemental sulfur oxidising enzyme Sulfur Oxygenase Reductase (SOR) is very well investigated in acidothermophilic archaea, such as Acidianus brierleyi and Sulfolobus metallicus. In contrast, not much is known about the biochemistry of elemental sulfur oxidation in acidophilic bacteria. Recently, however, the SOR-encoding gene has been found also in a bacterial strain closely related to the moderate thermophile Acidithiobacillus caldus. Confusingly, for the latter species, also the involvement of the SOX system as well as thiosulfate:quinone oxidoreductase (TQO) and tetrathionate hydrolase (TTH) in sulfur compound oxidation has been proposed based on genome analysis. In this study, we have detected the sor-gene in other Acidithiobacillus caldus-like strains, isolated from various bioleaching habitats, indicating that SOR plays an important role in sulfur oxidation in this species. Based on sequence comparison, the new bacterial sor-genes are closely related and distant from the known archaeal sequences as well as from the SOR found in the neutrophilic bacterium Aquifex aeolicus. In addition, SOR activity has been detected in crude cell extracts from all Acidithiobacillus caldus-like strains tested. The enzyme is truly thermophilic as highest activities were achieved at 65 °C, which is far beyond the growth optimum of Acidithiobacillus caldus. This finding may give rise to the question whether the presence of SOR in Acidithiobacillus caldus is only relevant while growing at elevated temperatures. Currently, experiments are performed for testing this hypothesis (comparing growth and enzyme activities at 30 vs. 45 °C).
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Bennett, Richard, Isioma Osadebe, Rakesh Kumar, Peter Ó. Conghaile, and Dónal Leech. "Design of Experiments Approach to Provide Enhanced Glucose-oxidising Enzyme Electrode for Membrane-less Enzymatic Fuel Cells Operating in Human Physiological Fluids." Electroanalysis 30, no. 7 (March 30, 2018): 1438–45. http://dx.doi.org/10.1002/elan.201600402.
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Franco, E., RB Ferreira, and AN Teixeira. "Involvement of Membrane Damage in Stress-Induced Oxidative Deactivation of Ribulose Bisphosphate Carboxylase From Lemna minor." Functional Plant Biology 19, no. 3 (1992): 297. http://dx.doi.org/10.1071/pp9920297.
Full textAbstract:
Previous studies have shown that Lemna minor L. responds to an osmotic shock by producing an enzyme system capable of oxidising ribulose bisphosphate carboxylase (RuBP carboxylase; EC 4.1.1.39) to an acidic and catalytically inactive form. The induction of the oxidase system which occurs when Lemna is subjected to osmotic shock in the light is delayed by darkness and inhibited in the presence of protein synthesis inhibitors. When Lemna fronds are deprived of calcium, the oxidase system is induced in a manner identical to that observed during osmotic shock. Furthermore, a similar phenomenon is observed when the plants are incubated in the presence of membrane-damaging compounds such as filipin, ethanol or Triton X-100. This effect is reversed by the addition of compounds that are known to stabilise cellular membranes, namely calcium, polyamines and sterols. Our results suggest that osmotic shock, calcium starvation and other stress situations damage Lemna cellular membranes, releasing the oxidase system. The presumed membrane damage and the induction of the oxidase system may be somewhat related, as shown by the observation that, in the presence of certain membrane-damaging situations, membrane stabilisers not only protect Lemna membranes but also prevent the stress-induction of the oxidase system.
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Pokorska, Joanna, Karolina Poskart, Dominika Kułaj, Andrzej Ochrem, Magdalena Dusza, Zygmunt Gil, Ewa Świętek, and Joanna Makulska. "Effect of g.9476869G>A myeloperoxidase (MPO) gene polymorphism on the antioxidant activity of milk from Polish Holstein-Friesian cows of the Black-and-White variety (HO)." Journal of Dairy Research 84, no. 2 (May 2017): 159–64. http://dx.doi.org/10.1017/s0022029917000139.
Full textAbstract:
Myeloperoxidase (MPO) is an important enzyme, which is one of the components of the antibacterial system in neutrophils and monocytes. MPO participates in the inflammatory response in multiple locations in the body, including the mammary glands. As a result of the activity of MPO, many oxidising compounds as well as reactive oxygen species are generated. It seems that myeloperoxidase may be a marker linking inflammation processes and oxidative stress. So far, there are no literature data on the association between the MPO gene polymorphism and the antioxidant properties of milk. The aim of the study was to analyse the effect of g.9476869G > A polymorphism of myeloperoxidase (MPO) gene and age of cows on the antioxidant activity of milk and other milk traits in Polish Holstein-Friesian cows. Polymorphism of MPO gene was identified by the PCR-RFLP method using the HphI endonuclease. The total antioxidant capacity of milk samples was measured by the Trolox Equivalent Antioxidant Capacity (TEAC) method. It was found that the GG genotype was the most frequent (0·606). The genotype at the tested MPO locus and the age of the animals affected the antioxidant activity of milk. Milk from cows with the GA genotype was characterised by a significantly higher antioxidant activity than milk from cows with the GG genotype (P< 0·0001). The analysis of interaction showed that cows with the GA genotype and older than 6·5 years produced milk with a significantly higher antioxidant activity compared with younger cows with the same genotype (P< 0·0001), as well as cows with the GG genotype of all ages (P< 0·0001).
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Aitken, R. J., D. Harkiss, W. Knox, M. Paterson, and D. S. Irvine. "A novel signal transduction cascade in capacitating human spermatozoa characterised by a redox-regulated, cAMP-mediated induction of tyrosine phosphorylation." Journal of Cell Science 111, no. 5 (March 1, 1998): 645–56. http://dx.doi.org/10.1242/jcs.111.5.645.
Full textAbstract:
Capacitation is a priming event that renders mammalian spermatozoa responsive to signals originating from the cumulus-oocyte complex. The attainment of a capacitated state is dependent upon an increase in tyrosine phosphorylation and results in the acquisition of responsiveness to physiological agonists such as progesterone and ZP3. In this study we have shown that this capacitation-dependent increase in tyrosine phosphorylation is controlled by a unique redox-regulated, cAMP-mediated, signal transduction cascade. Either stimulation of reactive oxygen species generation or elevation of intracellular cAMP induced increases in phosphotyrosine expression by human spermatozoa and enhanced their responsiveness to progesterone. Ultimate convergence of the redox- and cAMP-regulated pathways was indicated by the ability of the protein kinase A inhibitor, H89, to block both modes of signal transduction. Furthermore, the fact that the redox-regulated pathway could be silenced by catalase, while this enzyme had no effect on the cAMP-mediated response, indicated that oxidant generation must lie upstream from cAMP in the reaction sequence. In keeping with this conclusion, a functional association was demonstrated between the redox status of human spermatozoa and their cAMP content. The continuous production of reactive oxygen species was also shown to be necessary for the protein kinase A-tyrosine phosphorylation axis to remain functional. If the generation of oxidising conditions during capacitation was prevented with 2-mercaptoethanol, 2-deoxyglucose or the flavoprotein inhibitor, diphenylene iodonium, then cAMP could no longer trigger tyrosine phosphorylation. These data support a model for human sperm capacitation as a redox-regulated process, involving a unique sequence of interactive events including reactive oxygen species production, elevation of intracellular cAMP, stimulation of protein kinase A and the induction of tyrosine phosphorylation. This is the first report of such a signal transduction cascade and may have implications for the functional significance of reactive oxygen metabolites in other cell types.
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Marchioli, Roberto. "Vitamin E and Cardiovascular Disease." Thrombosis and Haemostasis 85, no. 05 (2001): 758–60. http://dx.doi.org/10.1055/s-0037-1615713.
Full textAbstract:
SummaryInterest in the use of antioxidants for the treatment of human disease, and in the role of dietary antioxidants in the prevention of disease development, has been sustained for at least two decades. Several anti-oxidant protective mechanisms exist and constitute a primary defensive system including enzymatic defences (glutathione peroxidase and superoxide dismutase, which depend on the presence of ions such as selenium, zinc, copper, and manganese) and naturally occurring vita-mins such as vitamin E, vitamin A, beta-carotene, and vitamin C. The most important natural antioxidants are vitamin E (in the form of α-, β-, γ-, and δ-tocopherols), beta-carotene, vitamin C and selenium (fundamental constituent of glutathione-peroxidase, i.e., an enzyme with antioxidant function). The first two are lipophilic substances whilst ascorbic acid is hydrophilic. Each antioxidant has a different important mechanism of action since oxidative damage can be caused by lipid- or water-soluble molecules. Lipid-soluble antioxidants are likely to be very important in preventing the peroxidation of low-density lipo-proteins (LDL) and this action could be paramount in the prevention of atherosclerosis. On the other hand, water-soluble antioxidants could be useful where a water-soluble oxidative stress occurs (e.g., inflammation). As lipophilic molecules, vitamin E and beta-carotene are incorporated into the LDL particle. Vitamin E is the main lipid-soluble chain-breaking antioxidant in plasma and tissues and converts the peroxyl-free radical to hydroperoxide, a less reactive radical. It acts as a first-line anti-oxidative defence of LDL particles, protecting unsatu-rated fatty acids from peroxidation. Beta-carotene is a carotenoid (precursor of vitamin A, pro-vitamin) that acts as scavenger of oxidising radicals such as singlet oxygen and is a second-line antioxidative defence of LDL cholesterol. Vitamin C (ascorbic acid) can react with singlet oxygen, superoxide, hydroxyl radicals, and is the first line of antioxi-dative defence in water-soluble compartments. In addition, it plays an important role in regenerating reduced -tocopherol.
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Haddad Momeni, Majid, Folmer Fredslund, Bastien Bissaro, Olanrewaju Raji, Thu V. Vuong, Sebastian Meier, Tine Sofie Nielsen, et al. "Discovery of fungal oligosaccharide-oxidising flavo-enzymes with previously unknown substrates, redox-activity profiles and interplay with LPMOs." Nature Communications 12, no. 1 (April 9, 2021). http://dx.doi.org/10.1038/s41467-021-22372-0.
Full textAbstract:
AbstractOxidative plant cell-wall processing enzymes are of great importance in biology and biotechnology. Yet, our insight into the functional interplay amongst such oxidative enzymes remains limited. Here, a phylogenetic analysis of the auxiliary activity 7 family (AA7), currently harbouring oligosaccharide flavo-oxidases, reveals a striking abundance of AA7-genes in phytopathogenic fungi and Oomycetes. Expression of five fungal enzymes, including three from unexplored clades, expands the AA7-substrate range and unveils a cellooligosaccharide dehydrogenase activity, previously unknown within AA7. Sequence and structural analyses identify unique signatures distinguishing the strict dehydrogenase clade from canonical AA7 oxidases. The discovered dehydrogenase directly is able to transfer electrons to an AA9 lytic polysaccharide monooxygenase (LPMO) and fuel cellulose degradation by LPMOs without exogenous reductants. The expansion of redox-profiles and substrate range highlights the functional diversity within AA7 and sets the stage for harnessing AA7 dehydrogenases to fine-tune LPMO activity in biotechnological conversion of plant feedstocks.
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Huang, Huaping, Mingjing Chen, Feng Liu, Haifeng Wu, Jie Wang, Jialiang Chen, Meihua Liu, and Xi Li. "N-acetylcysteine tiherapeutically protects against pulmonary fibrosis in a mouse model of silicosis." Bioscience Reports 39, no. 7 (July 2019). http://dx.doi.org/10.1042/bsr20190681.
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Abstract Silicosis is a lethal pneumoconiosis disease characterized by chronic lung inflammation and fibrosis. The present study was to explore the effect of against crystalline silica (CS)-induced pulmonary fibrosis. A total of 138 wild-type C57BL/6J mice were divided into control and experimental groups, and killed on month 0, 1, 2, 3, 4, and 5. Different doses of N-acetylcysteine (NAC) were gavaged to the mice after CS instillation to observe the effect of NAC on CS induced pulmonary fibrosis and inflammation. The pulmonary injury was evaluated with Hematoxylin and eosin/Masson staining. Reactive oxygen species level was analyzed by DCFH-DA labeling. Commercial ELISA kits were used to determine antioxidant activity (T-AOC, glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) and cytokines (TNF-α, IL-1β, IL-4, and IL-6). The expression of oxidising enzymes (NOX2, iNOS, SOD2, and XO) were detected by real time PCR. Immunohistochemistry (IHC) staining was performed to examine epithelial-mesenchymal transition-related markers. The mice treated with NAC presented markedly reduced CS-induced pulmonary injury and ameliorated CS-induced pulmonary fibrosis and inflammation. The level of malondialdehyde was reduced, while the activities of GSH-PX, SOD, and T-AOC were markedly enhanced by NAC. We also found the down-regulation of oxidising enzymes (NOX2, iNOS, SOD2, and XO) after NAC treatment. Moreover, E-cadherin expression was increased while vimentin and Cytochrome C expressions were decreased by NAC. These encouraging findings suggest that NAC exerts pulmonary protective effects in CS-induced pulmonary fibrosis and might be considered as a promising agent for the treatment of silicosis.
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Zhyvoloup, Alexander, Bess Yi Kun Yu, Jovana Baković, Mathew Davis-Lunn, Maria-Armineh Tossounian, Naam Thomas, Yugo Tsuchiya, et al. "Analysis of disulphide bond linkage between CoA and protein cysteine thiols during sporulation and in spores of Bacillus species." FEMS Microbiology Letters 367, no. 23 (November 18, 2020). http://dx.doi.org/10.1093/femsle/fnaa174.
Full textAbstract:
ABSTRACT Spores of Bacillus species have novel properties, which allow them to lie dormant for years and then germinate under favourable conditions. In the current work, the role of a key metabolic integrator, coenzyme A (CoA), in redox regulation of growing cells and during spore formation in Bacillus megaterium and Bacillus subtilis is studied. Exposing these growing cells to oxidising agents or carbon deprivation resulted in extensive covalent protein modification by CoA (termed protein CoAlation), through disulphide bond formation between the CoA thiol group and a protein cysteine. Significant protein CoAlation was observed during sporulation of B. megaterium, and increased largely in parallel with loss of metabolism in spores. Mass spectrometric analysis identified four CoAlated proteins in B. subtilis spores as well as one CoAlated protein in growing B. megaterium cells. All five of these proteins have been identified as moderately abundant in spores. Based on these findings and published studies, protein CoAlation might be involved in facilitating establishment of spores’ metabolic dormancy, and/or protecting sensitive sulfhydryl groups of spore enzymes.
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Kupchyk, O. "DETERMINING HEAVY METALS IN MUSHROOM SAMPLES BY STRIPPING VOLT-AMMETRY." Food Science and Technology 12, no. 2 (July 2, 2018). http://dx.doi.org/10.15673/fst.v12i2.939.
Full textAbstract:
Industrial cultivation of mushrooms in Ukraine in recent years has been developing at a rather high pace. A promising consumer of Ukrainian mushrooms may be the European Union market. But mushrooms are not delivered there in significant volumes due to quite high requirements for the product quality. From the biosphere, heavy metals can enter the mushrooms and make them potentially dangerous for people. The content of heavy metals: zinc, cadmium, lead, and copper in edible mushrooms (ceps, chanterelles, butter mushrooms, saffron milk-caps, and champignons) has been studied by using the stripping voltammetry method after the destruction of the matrix of mushroom samples. Sample preparation was done by the method of “wet” mineralisation with oxidising mixtures of various compositions using inorganic acids (nitrate, chloride, sulfate), and an oxidiser – hydrogen peroxide. Besides, dry ashing was used. As a result of the experiment, it has been found that the most effective method of extracting the ions of heavy metals and ensuring the accuracy of the analysis is sample preparation using nitric acid and hydrogen peroxide. The concentrations of the metals under analysis are calculated on the dry basis (mg/kg). The concentrations found for bioelements that are contained in enzymes in living organisms (zinc, copper, and toxic elements – lead and cadmium), are within the range of 51.3–72.9; 3.0–10.3; 0.2–1.32, and 0.06–0.33 mg/kg, respectively. Thus, by arranging the samples of the mushrooms under study in ascending order by the specified total content of heavy metals, we obtain the following series: ceps – butter mushrooms – chanterelles – saffron milk caps – champignons. Besides, the relative error of analysis has been calculated, and the replicability of the selected research method has been estimated. Thus, the method of stripping voltammetry can be applied in quantitative determination of heavy metals in mushroom samples.
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Shikongo-Nambabi, Martha Naita Namwaala Nangulohi, Abraham Shoolongela, and Martin Schneider. "Control of Bacterial Contamination during Marine Fish Processing." Journal of Biology and Life Science 3, no. 1 (November 30, 2011). http://dx.doi.org/10.5296/jbls.v3i1.1033.
Full textAbstract:
Fish is a vital source of nutrients to humans due to its proteinaceous nature, high content of unsaturated fatty acids and low contents of carbohydrates. Fish consumption therefore is recommended to circumvent lifestyle diseases associated with the consumption of red meat. In their natural environments fish are exposed to a myriad of microorganisms some of which compromise the shelf life of the product and/or safety in humans. Most fish factories are located along coasts hence find it economical to make use of processed sea water in processing. Processed sea water however can be a source of microbial contamination to fish. Prudent quality assurance regimes are therefore required to minimise low fish quality products and promote consumer safety. Fish factories are also vulnerable to biofilm formation on surfaces and within water distribution pipes. Biofilms result from bacterial attachment and growth in aqueous environments within which pathogenic and spoilage bacteria become resistant to cleaning and sanitising agents. Biofilms defy efforts directed at maximising the safety and quality of fish. This article reviews the conditions permissible to bacterial contamination in marine fish factories. The role of water in bacterial contamination and survival has been highlighted. Bacterial pathogens commonly associated with fish factories and their survival strategies have also been discussed. The use of a number of selected oxidising agents and UV irradiation as sanitizers in marine fish processing have been explored. The fundamental antimicrobial mechanisms of chlorine, ozone and H2O2 is the generation of toxic metabolic intermediates that damage microbial structural components, enzymes and cell membranes causing metabolic paralysis and leakage of cytoplasmic contents and cell death. UV radiation damages DNA and hinders gene expression processes. Controlling bacteria biofilm by means of sanitising agents has been well experimented in fresh water systems, but knowledge about disinfection of marine waters is still lacking. The review concludes that in order to optimise the microbiological quality of marine fish, suitable disinfectants effective in sea water need to be explored and authenticated. It is therefore necessary to conduct cost/benefit studies of sanitising agent agents that are effective in sea water and their impact on the quality and safety of marine fish. Key words: Biofilms Factories Sanitation Seafood.
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Areskogh, Dimitri, Jiebing Li, Paula Nousiainen, Göran Gellerstedt, Jussi Sipilä, and Gunnar Henriksson. "Oxidative polymerisation of models for phenolic lignin end-groups by laccase." Holzforschung 64, no. 1 (January 1, 2010). http://dx.doi.org/10.1515/hf.2010.001.
Full textAbstract:
AbstractThe redox enzyme laccase can lead to cross-linking of lignin molecules by oxidising phenolic end groups to resonance-stabilised radicals that can undergo radical coupling to form covalent bonds. This property has potential for many technical applications. However, laccase treatment can also lead to degradation. Experiments were performed with two laccases of different oxidation potential and pH and temperature optima. The predominant reaction following laccase oxidation is the formation of 5-5′ and 4-O-5′ bonds. If the 5-position is blocked, other reactions occur, including coupling of the 1-position and oxidation of the α-position, which aggravates cross-linking of different lignin molecules. The product profile generated by the two laccases is somewhat different, mainly because of the different pH rather than differences in enzyme activity. Reaction mechanisms and the technical and biological significance of the results are discussed.
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Junker, Katja, Ivan Gitsov, Nick Quade, and Peter Walde. "Preparation of aqueous polyaniline-vesicle suspensions with class III peroxidases. Comparison between horseradish peroxidase isoenzyme C and soybean peroxidase." Chemical Papers 67, no. 8 (January 1, 2013). http://dx.doi.org/10.2478/s11696-013-0307-y.
Full textAbstract:
AbstractAniline was polymerised enzymatically in aqueous solution at pH = 4.3 and 25°C in the presence of submicrometer-sized vesicles formed from sodium bis(2-ethylhexyl)sulphosuccinate (AOT). H2O2 served as oxidant and the enzyme used was either horseradish peroxidase isoenzyme C (HRPC) or soybean peroxidase (SBP), both being class III peroxidases. From previous studies with HRPC, it is known that stable vesicle suspensions containing the emeraldine salt form of polyaniline (PANI-ES) can be obtained within 1–2 days with a 90–95 % yield, provided that optimal reaction conditions are applied. Unfortunately, HRPC becomes inactivated during polymerisation. In the present study, a linear dendritic block copolymer was added to HRPC, resulting in higher operational enzyme stability; the stabilising effect, however, was too small to afford a substantial decrease in the required amount of enzyme. Moreover, replacing HRPC with SBP was of no advantage, although SBP is known to be more stable towards inactivation by H2O2 than HRPC. By contrast, SBP was found to be much slower in oxidising aniline, and complete inactivation of SBP occurred before all the aniline monomers were oxidised, leading to low yields and the formation of over-oxidised products. The same was observed for HRP isoenzyme A2. Reactions without vesicles indicated that peroxidase inactivation was probably caused by PANI-ES.
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Sahu, Bindia, Jaya Prakash Alla, Gladstone Christopher Jayakumar, and Ashok Raj. "Influence of Benzenecarboperoxoic Acid on Chamois Leather Process." Journal of the American Leather Chemists Association 115, no. 2 (January 27, 2020). http://dx.doi.org/10.34314/jalca.v115i2.1484.
Full textAbstract:
Stabilization of collagen against heat and enzyme is a key objective in the tanning process. In oil tanning, fatty acid present in the oil is oxidised mainly into aldehydes which interects with ? amino groups of collagen to form stable covalent cross links. Conventionally, oil tanning consumes time from two to three weeks which primarily depends on the type of oil and oxidation method for completion of tanning. In the present research, the duration of oil oxidation is reduced using benzenecarboperoxoic acid (PBA). It has been observed that PBA significantly reduces oil tanning duration from two weeks to 4 days. Moreover, the water absorption capacity of experimental leather has also increased by approximately 48% (1% PBA) compared to control leather. Physical strength properties such as tensile and percentage elongation values have also found to meet the standard norms. In addition to this organoleptic properties are also on par with control leather. The present study focus on the accelaration of chamois process for making leather, using PBA as an oxidising agent.