Letteratura scientifica selezionata sul tema "Proteins Oxidation"
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Articoli di riviste sul tema "Proteins Oxidation"
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Pattison, David I., Aldwin Suryo Rahmanto e Michael J. Davies. "Photo-oxidation of proteins". Photochem. Photobiol. Sci. 11, n. 1 (2012): 38–53. http://dx.doi.org/10.1039/c1pp05164d.
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FU, Shanlin, Min-Xin FU, W. John BAYNES, R. Suzanne THORPE e T. Roger DEAN. "Presence of dopa and amino acid hydroperoxides in proteins modified with advanced glycation end products (AGEs): amino acid oxidation products as a possible source of oxidative stress induced by AGE proteins". Biochemical Journal 330, n. 1 (15 febbraio 1998): 233–39. http://dx.doi.org/10.1042/bj3300233.
Testo completoAbstract (sommario):
Glycation and subsequent Maillard or browning reactions of glycated proteins, leading to the formation of advanced glycation end products (AGEs), are involved in the chemical modification of proteins during normal aging and have been implicated in the pathogenesis of diabetic complications. Oxidative conditions accelerate the browning of proteins by glucose, and AGE proteins also induce oxidative stress responses in cells bearing AGE receptors. These observations have led to the hypothesis that glycation-induced pathology results from a cycle of oxidative stress, increased chemical modification of proteins via the Maillard reaction, and further AGE-dependent oxidative stress. Here we show that the preparation of AGE-collagen by incubation with glucose under oxidative conditions in vitro leads not only to glycation and formation of the glycoxidation product Nε-(carboxymethyl)lysine (CML), but also to the formation of amino acid oxidation products on protein, including m-tyrosine, dityrosine, dopa, and valine and leucine hydroperoxides. The formation of both CML and amino acid oxidation products was prevented by anaerobic, anti-oxidative conditions. Amino acid oxidation products were also formed when glycated collagen, prepared under anti-oxidative conditions, was allowed to incubate under aerobic conditions that led to the formation of CML. These experiments demonstrate that amino acid oxidation products are formed in proteins during glycoxidation reactions and suggest that reactive oxygen species formed by redox cycling of dopa or by the metal-catalysed decomposition of amino acid hydroperoxides, rather than by redox activity or reactive oxygen production by AGEs on protein, might contribute to the induction of oxidative stress by AGE proteins.
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Burgoyne, Joseph R., e Philip Eaton. "Contemporary techniques for detecting and identifying proteins susceptible to reversible thiol oxidation". Biochemical Society Transactions 39, n. 5 (21 settembre 2011): 1260–67. http://dx.doi.org/10.1042/bst0391260.
Testo completoAbstract (sommario):
Elevated protein oxidation is a widely reported hallmark of most major diseases. Historically, this ‘oxidative stress’ has been considered causatively detrimental, as the protein oxidation events were interpreted simply as damage. However, recent advances have changed this antiquated view; sensitive methodology for detecting and identifying proteins susceptible to oxidation has revealed a fundamental role for this modification in physiological cell signalling during health. Reversible protein oxidation that is dynamically coupled with cellular reducing systems allows oxidative protein modifications to regulate protein function, analogous to phosphoregulation. However, the relatively labile nature of many reversible protein oxidation states hampers the reliable detection and identification of modified proteins. Consequently, specialized methods to stabilize protein oxidation in combination with techniques to detect specific types of modification have been developed. Here, these techniques are discussed, and their sensitivity, selectivity and ability to reliably identify reversibly oxidized proteins are critically assessed.
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Pandey, Kanti Bhooshan, Mohd Murtaza Mehdi, Pawan Kumar Maurya e Syed Ibrahim Rizvi. "Plasma Protein Oxidation and Its Correlation with Antioxidant Potential During Human Aging". Disease Markers 29, n. 1 (2010): 31–36. http://dx.doi.org/10.1155/2010/964630.
Testo completoAbstract (sommario):
Previous studies have indicated that the main molecular characteristic of aging is the progressive accumulation of oxidative damages in cellular macromolecules. Proteins are one of the main molecular targets of age-related oxidative stress, which have been observed during aging process in cellular systems. Reactive oxygen species (ROS) can lead to oxidation of amino acid side chains, formation of protein-protein cross-linkages, and oxidation of the peptide backbones. In the present study, we report the age-dependent oxidative alterations in biomarkers of plasma protein oxidation: protein carbonyls (PCO), advanced oxidation protein products (AOPPs) and plasma total thiol groups (T-SH) in the Indian population and also correlate these parameters with total plasma antioxidant potential. We show an age dependent decrease in T-SH levels and increase in PCO and AOPPs level. The alterations in the levels of these parameters correlated significantly with the total antioxidant capacity of the plasma. The levels of oxidized proteins in plasma provide an excellent biomarker of oxidative stress due to the relative long half-life of such oxidized proteins.
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Rogers, K. R., C. J. Morris e D. R. Blake. "Oxidation of thiol in the vimentin cytoskeleton". Biochemical Journal 275, n. 3 (1 maggio 1991): 789–91. http://dx.doi.org/10.1042/bj2750789.
Testo completoAbstract (sommario):
Sublethal doses of H2O2, which induces oxidative stress, cause substantial alteration to the vimentin cytoskeleton in various cell types. We have used a thiol-blot assay to assess thiol status in individual proteins from cell extracts. Vimentin thiol is oxidized in preference to other cytoskeleton proteins. Immunoblot analysis also demonstrated a loss of reactivity to an anti-vimentin monoclonal antibody under non-reducing conditions, possibly due to thiol-group oxidation. During induced oxidative stress a number of proteins become associated with the cytoskeleton extracts.
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Lawal, Remilekun O., Fabrizio Donnarumma e Kermit K. Murray. "Electrospray Photochemical Oxidation of Proteins". Journal of The American Society for Mass Spectrometry 30, n. 11 (5 settembre 2019): 2196–99. http://dx.doi.org/10.1007/s13361-019-02313-4.
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Hambly, David M., e Michael L. Gross. "Cold Chemical Oxidation of Proteins". Analytical Chemistry 81, n. 17 (settembre 2009): 7235–42. http://dx.doi.org/10.1021/ac900855f.
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Simpson, Richard J. "Performic Acid Oxidation of Proteins". Cold Spring Harbor Protocols 2007, n. 3 (marzo 2007): pdb.prot4698. http://dx.doi.org/10.1101/pdb.prot4698.
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Luna, Carolina, e Mario Estévez. "Oxidative damage to food and human serum proteins: Radical-mediated oxidation vs. glyco-oxidation". Food Chemistry 267 (novembre 2018): 111–18. http://dx.doi.org/10.1016/j.foodchem.2017.06.154.
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Bruckbauer, Steven T., Benjamin B. Minkoff, Michael R. Sussman e Michael M. Cox. "Proteome Damage Inflicted by Ionizing Radiation: Advancing a Theme in the Research of Miroslav Radman". Cells 10, n. 4 (20 aprile 2021): 954. http://dx.doi.org/10.3390/cells10040954.
Testo completoAbstract (sommario):
Oxidative proteome damage has been implicated as a major contributor to cell death and aging. Protein damage and aging has been a particular theme of the recent research of Miroslav Radman. However, the study of how cellular proteins are damaged by oxidative processes is still in its infancy. Here we examine oxidative changes in the proteomes of four bacterial populations—wild type E. coli, two isolates from E. coli populations evolved for high levels of ionizing radiation (IR) resistance, and D. radiodurans—immediately following exposure to 3000 Gy of ionizing radiation. By a substantial margin, the most prominent intracellular oxidation events involve hydroxylation of methionine residues. Significant but much less frequent are carbonylation events on tyrosine and dioxidation events on tryptophan. A few proteins are exquisitely sensitive to targeted oxidation events, notably the active site of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) in E. coli. Extensive experimental evolution of E. coli for IR resistance has decreased overall proteome sensitivity to oxidation but not to the level seen in D. radiodurans. Many observed oxidation events may reflect aspects of protein structure and/or exposure of protein surfaces to water. Proteins such as GAPDH and possibly Ef-Tu may have an evolved sensitivity to oxidation by H2O2.
Tesi sul tema "Proteins Oxidation"
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Osborn, Anna. "Measurements of Human Plasma Oxidation". Thesis, University of Canterbury. Biological Sciences, 2006. http://hdl.handle.net/10092/1426.
Testo completoAbstract (sommario):
The oxidation of lipids and antioxidants has been extensively studied in human plasma but little attention has been given to how plasma proteins are oxidised. Proteins make up the majority of biomolecules in cells and plasma and therefore are the most likely reactants with oxidants and free radicals. Previous studies in the laboratory had shown that peroxyl radicals generated by the thermolytic decay of 2-azobis (2-amdinopropane) dihydrochloride (AAPH) generated significant amounts of protein hydroperoxides, but only after a six hour lag period. In this study the existence of the six hour lag period was confirmed and shown by dialysis of the plasma to be due to the presence of low molecular weight antioxidants. The addition of both uric acid and ascorbic acid to the dialysed plasma restored the lag phase suggesting that in vivo these antioxidants act to prevent protein hydroperoxide formation. Lipid oxidation was also observed in the plasma but only after a two hour lag phase. This was the first time lipid oxidation has been observed in the absence of protein oxidation. The lipid lag phase was also abolished by dialysis of the plasma and restored by the addition of ascorbic acid and uric acid. The kinetics of tocopherol loss suggests that the tocopherol radicals act to inhibit lipid oxidation by transferring the electrons to the water-soluble ascorbate. The loss of ascorbate appears to cause the formation of a tocopherol radical mediate the lipid peroxidation process. Overall the data shows ascorbic acid scavenging the peroxyl radicals while uric acid acts to reduce the overall AAPH generated radical flux. In a separate investigation, the production of protein-bound DOPA (PB-DOPA) on albumin during X-ray radiolysis and copper mediate Fenton oxidation was investigated using a fluorescence based derivatisation method (ED-DOPA), which was compared with the more specific acid hydrolysis and HPLC analysis method. The ED-DOPA method consistently gave a much higher reading that the HPLC based methods, suggesting that the ED-DOPA method was measuring DOPA plus DOPA oxidation products. This was confirmed by oxidising X-ray radiolysis generated PB-DOPA with Cu++ to cause DOPA oxidation. The Cu++ treatment drastically increased the level of signal given by the ED-DOPA assay while HPLC analysis showed all the DOPA had been oxidised.
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Du, Aiguo. "Prediction of oxidation states of cysteines and disulphide bridges in proteins". unrestricted, 2007. http://etd.gsu.edu/theses/available/etd-11272007-024411/.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Georgia State University, 2007.Title from file title page. Y. Pan, committee chair; G. Qin, A. Bourgeois, A. Zelikovski, committee members. Electronic text (124 p. : ill. (some col.)) : digital, PDF file. Description based on contents viewed June 3, 2008. Includes bibliographical references (p. 111-124).
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Beilen, Jan Berthold van. "Alkane oxidation by Pseudomonas oleovorans: genes and proteins". [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 1994. http://irs.ub.rug.nl/ppn/292892500.
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Fredriksson, Åsa. "On the role of protein oxidation and heat shock proteins in senescence and fitness /". Göteborg : Göteborg University, 2006. http://www.loc.gov/catdir/toc/fy0708/2006421399.html.
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Shutova, Tatiana. "Photosynthetic water oxidation : the function of two extrinsic proteins". Doctoral thesis, Umeå : Department of Plant Physiology, Umeå Univ, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1476.
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Kapavarapu, Susmita. "Extracellular expression, oxidation and purification of hen egg white lysozyme double mutant (H15S+N77H) /". Connect to resource online, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1197658857.
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Wood, Geoffrey Paul Farra. "Theoretical Investigations of Radical-Mediated Protein Oxidation". Thesis, The University of Sydney, 2006. http://hdl.handle.net/2123/1413.
Testo completoAbstract (sommario):
This thesis primarily details the application of high-level ab initio quantum chemistry techniques in order to understand aspects of free-radical mediated protein oxidation. Traditionally, product analysis and electron paramagnetic resonance (EPR) spectroscopy are the primary means for elucidating the chemistry of protein oxidation. However, in experiments involving relatively small proteins reacting with a controlled radical-flux, a vast array of compounds can be produced, which are often difficult to analyse. Quantum chemical techniques on the other hand, can calculate the properties of any particular species directly, without suffering from the problems associated with experiment, such as side-reactions and chain processes. The results presented in this thesis are aimed at elucidating mechanistic details of protein oxidation, which might otherwise be difficult to probe experimentally. Chapter 1 gives an overview of the free-radical hypothesis of disease and ageing. Protein-derived radicals can undergo a variety of reactions, with the particular reaction that occurs depending on numerous aspects. Many types of reactions have been identified through radiolysis experiments of amino acids, and these are detailed in this chapter. In addition, the key reactive species are characterized and their different chemistries explained. Chapter 2 details the theoretical tools used throughout this thesis. Species with unpaired electrons (radicals) present unique problems for quantum chemistry to handle, thus an appropriate choice of theoretical technique is needed. The approach taken in this thesis is to use high-level compound methods, many of which have been directly formulated to give improved results for radical species, to provide benchmark quality results by which other less demanding techniques can be assessed. During the course of this study, it became apparent there was a void in the armoury of tools that could be used for the theoretical chemistry calculations. Chapter 3 details the formulation of a new tool in an attempt to fill this gap. Historically, the formulation of this new procedure came after much of the work in this thesis had been carried out. Thus, for the study of many of the reactions of this thesis the new method has not been used. However, it is most appropriate to place its formulation after summarizing the current status of techniques in common use today. Chapters 4 and 5 detail computations carried out on models of peptides containing backbone carbon- and nitrogen-centered radicals. A number of different theoretical techniques are used in these chapters, ranging from the highly accurate and computationally intensive to the less reliable and less demanding. The highly accurate techniques are used to gauge the accuracy of the other less demanding theoretical techniques so that the latter can be used with confidence in larger systems. Not only is the choice of theoretical technique important but also the judicious choice of model is essential. With this in mind, models are incrementally built until convergence of the particular property of interest is reached. Chapters 6 and 7 detail the calculations of β-scission reactions of alkoxyl radicals, which are a particular class of reaction known to occur on peptide backbones. Alkoxyl radicals are particularly difficult for theory to describe correctly. Therefore, Chapter 6 extensively assesses and then identifies the theoretical methods needed to portray them. Chapter 7 uses the techniques identified in the previous chapter in order to predict how the preference for a particular type of β-scission reaction changes.
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Wood, Geoffrey Paul Farra. "Theoretical Investigations of Radical-Mediated Protein Oxidation". University of Sydney, 2006. http://hdl.handle.net/2123/1413.
Testo completoAbstract (sommario):
Doctor of Philosophy (PhD)This thesis primarily details the application of high-level ab initio quantum chemistry techniques in order to understand aspects of free-radical mediated protein oxidation. Traditionally, product analysis and electron paramagnetic resonance (EPR) spectroscopy are the primary means for elucidating the chemistry of protein oxidation. However, in experiments involving relatively small proteins reacting with a controlled radical-flux, a vast array of compounds can be produced, which are often difficult to analyse. Quantum chemical techniques on the other hand, can calculate the properties of any particular species directly, without suffering from the problems associated with experiment, such as side-reactions and chain processes. The results presented in this thesis are aimed at elucidating mechanistic details of protein oxidation, which might otherwise be difficult to probe experimentally. Chapter 1 gives an overview of the free-radical hypothesis of disease and ageing. Protein-derived radicals can undergo a variety of reactions, with the particular reaction that occurs depending on numerous aspects. Many types of reactions have been identified through radiolysis experiments of amino acids, and these are detailed in this chapter. In addition, the key reactive species are characterized and their different chemistries explained. Chapter 2 details the theoretical tools used throughout this thesis. Species with unpaired electrons (radicals) present unique problems for quantum chemistry to handle, thus an appropriate choice of theoretical technique is needed. The approach taken in this thesis is to use high-level compound methods, many of which have been directly formulated to give improved results for radical species, to provide benchmark quality results by which other less demanding techniques can be assessed. During the course of this study, it became apparent there was a void in the armoury of tools that could be used for the theoretical chemistry calculations. Chapter 3 details the formulation of a new tool in an attempt to fill this gap. Historically, the formulation of this new procedure came after much of the work in this thesis had been carried out. Thus, for the study of many of the reactions of this thesis the new method has not been used. However, it is most appropriate to place its formulation after summarizing the current status of techniques in common use today. Chapters 4 and 5 detail computations carried out on models of peptides containing backbone carbon- and nitrogen-centered radicals. A number of different theoretical techniques are used in these chapters, ranging from the highly accurate and computationally intensive to the less reliable and less demanding. The highly accurate techniques are used to gauge the accuracy of the other less demanding theoretical techniques so that the latter can be used with confidence in larger systems. Not only is the choice of theoretical technique important but also the judicious choice of model is essential. With this in mind, models are incrementally built until convergence of the particular property of interest is reached. Chapters 6 and 7 detail the calculations of β-scission reactions of alkoxyl radicals, which are a particular class of reaction known to occur on peptide backbones. Alkoxyl radicals are particularly difficult for theory to describe correctly. Therefore, Chapter 6 extensively assesses and then identifies the theoretical methods needed to portray them. Chapter 7 uses the techniques identified in the previous chapter in order to predict how the preference for a particular type of β-scission reaction changes.
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Yi, Dong-Hui Chemistry Faculty of Science UNSW. "The Study of Biomarkers of Protein Oxidative Damage and Aging by Mass Spectrometry". Awarded by:University of New South Wales. School of Chemistry, 1999. http://handle.unsw.edu.au/1959.4/17636.
Testo completoAbstract (sommario):
The physiologically important free radicals, nitrogen monoxide and superoxide, can combine to form the reactive intermediate peroxynitrite. Peroxynitrite can react with proteins and their constituent amino acids, such as tyrosine, resulting in protein peroxidation, oxidation and nitration. The nitration of proteins, assessed by the analysis of 3-nitrotyrosine, is a proposed index of pathophysiological activity of peroxynitrite. The aim of the work was to investigate the reaction products between peroxynitrite and protein, develop an assay for 3-nitrotyrosine and measure its levels in biological samples. To study the amino acid products arising from the reaction of peroxynitrite and protein, both liquid chromatography (LC) and gas chromatography (GC) combined with mass spectrometry (MS) were adopted. Approaches to 3-nitrotyrosine assay development were first, to take advantage of the intrinsic sensitivity of electron capture negative ionization GC-MS. Secondly, to avoid possible artefactual problems associated with the derivatisation step in GC-MS, an assay for 3-nitrotyrosine based on combined LC-MS-MS was developed. When a selection of peptides was exposed to peroxynitrite under physiological conditions in vitro, the hydrolysis products showed that 3-nitrotyrosine was the major product. Detectable minor products were 3,5-dinitrotyrosine and DOPA. The GC-MS assay was found to be fraught with difficulty due to artefactual formation of 3-nitrotyrosine. In order to quantify and correct for artefact formation, this complication was approached by incorporating a second isotopomer. This method, however, was confounded by large errors that reduced the overall sensitivity. Either negative or zero levels of endogenous 3-nitrotyrosine were found in tested samples after correction for artefact formation. The LC-MS-MS assay was then used to analyse 3-nitrotyrosine levels in a range of biological samples, including human plasma from healthy volunteers, synovial fluid samples from arthritis patients and tissue extracts from a mouse model of amyotropic lateral sclerosis. In contrast to published data, 3-nitrotyrosine levels were found to be below the limit of detection (1 pg/????L, 10 pg o/c) for all samples - a result somewhat consistent with the negative GC-MS data. It is suggested that the high 3-nitrotyrosine levels previously reported in the literature might reflect artefactual generation of 3-nitrotyrosine and that other approaches to assessing pathophysiological nitration should be sought in future.
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Dales, Simon Leslie. "The structure, function and biosynthesis of proteins involved in methanol oxidation". Thesis, University of Southampton, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296270.
Testo completoLibri sul tema "Proteins Oxidation"
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Sharma, Virender K. Oxidation of Amino Acids, Peptides, and Proteins. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2012. http://dx.doi.org/10.1002/9781118482469.
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Fredriksson, Åsa. On the role of protein oxidation and heat shock proteins in senescence and fitness. Göteborg: Göteborg University, 2006.
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Davies, M. J. Radical-mediated protein oxidation: From chemistry to medicine. Oxford: Oxford University Press, 1997.
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1964-, Dalle-Donne Isabella, Scaloni Andrea e Butterfield D. Allan, a cura di. Redox proteomics: From protein modifications to cellular dysfunction and diseases. Hoboken, N.J: Wiley-Interscience, 2006.
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J, Lunec, a cura di. Measuring in vivo oxidative damage: A practical approach. Chichester: Wiley, 2000.
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Grune, Tilman, Betul Catalgol e Tobias Jung. Protein Oxidation and Aging. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2012. http://dx.doi.org/10.1002/9781118493038.
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Feige, Matthias J., a cura di. Oxidative Folding of Proteins. Cambridge: Royal Society of Chemistry, 2018. http://dx.doi.org/10.1039/9781788013253.
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1938-, Flohé L., e Harris James R, a cura di. Peroxiredoxin systems: Structures and functions. New York: Springer, 2007.
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Catala, Angel. Reactive oxygen species, lipid peroxidation, and protein oxidation. New York: Nova Publishers, 2014.
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Moroder, Luis, e Johannes Buchner, a cura di. Oxidative Folding of Peptides and Proteins. Cambridge: Royal Society of Chemistry, 2008. http://dx.doi.org/10.1039/9781847559265.
Testo completoCapitoli di libri sul tema "Proteins Oxidation"
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Stadtman, Earl R. "Free Radical Mediated Oxidation of Proteins". In Free Radicals, Oxidative Stress, and Antioxidants, 51–64. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4757-2907-8_5.
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Ochiai, Ei-Ichiro. "Oxidation—Reduction and Enzymes and Proteins". In General Principles of Biochemistry of the Elements, 53–95. Boston, MA: Springer US, 1987. http://dx.doi.org/10.1007/978-1-4684-5371-3_3.
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Moan, Natacha, Frédérique Tacnet e Michel B. Toledano. "Protein-Thiol Oxidation, From Single Proteins to Proteome-Wide Analyses". In Redox-Mediated Signal Transduction, 175–92. Totowa, NJ: Humana Press, 2008. http://dx.doi.org/10.1007/978-1-59745-129-1_13.
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Sizer, Irwin W. "Oxidation of Proteins by Tyrosinase and Peroxidase". In Advances in Enzymology - and Related Areas of Molecular Biology, 129–61. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2006. http://dx.doi.org/10.1002/9780470122594.ch4.
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Fournier, N. C., e M. A. Richard. "Role of fatty acid-binding protein in cardiac fatty acid oxidation". In Cellular Fatty Acid-binding Proteins, 149–59. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4615-3936-0_19.
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Soyer, Ayla, e Herbert O. Hultin. "Oxidation of Fish Sarcoplasmic Reticular Lipids and Proteins". In Quality Attributes of Muscle Foods, 269–76. Boston, MA: Springer US, 1999. http://dx.doi.org/10.1007/978-1-4615-4731-0_18.
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Jones, Lisa M. "Fast Photochemical Oxidation of Proteins for Structural Characterization". In Characterization of Protein Therapeutics using Mass Spectrometry, 343–70. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-1-4419-7862-2_9.
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Veerkamp, J. H., e H. T. B. van Moerkerk. "Fatty acid-binding protein and its relation to fatty acid oxidation". In Cellular Fatty Acid-Binding Proteins II, 101–6. Boston, MA: Springer US, 1993. http://dx.doi.org/10.1007/978-1-4615-3096-1_13.
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Chesworth, J. M., T. Stuchbury e J. R. Scaife. "Breakdown of Proteins and the Oxidation of Amino Acids". In An Introduction to Agricultural Biochemistry, 193–99. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-009-1441-4_14.
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Linssen, M. C. J. G., M. M. Vork, Y. F. de Jong, J. F. C. Glatz e G. J. van der Vusse. "Fatty acid oxidation capacity and fatty acid-binding protein content of different cell types isolated from rat heart". In Cellular Fatty Acid-binding Proteins, 19–25. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4615-3936-0_3.
Testo completoAtti di convegni sul tema "Proteins Oxidation"
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Munch, Katharina, Claire Berton-Carabin, Karin Schroen e Simeon Stoyanov. "Plant protein-stabilized emulsions: Implications of protein and non-protein components for lipid oxidation". In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/zznf4565.
Testo completoAbstract (sommario):
The use of plant proteins to stabilize oil-in-water (O/W) emulsions has been an increasing trend lately. The complexity of the available plant protein ingredients, along with the proteins’ physicochemical properties, require advanced processing that typically leads to substantial concentrations of non-protein components in the final isolates or concentrates. It is known that those components, such as polyphenols, phytic acid or phospholipids, can have a strong influence on the oxidative stability of emulsions. Thus, to understand the oxidative stability of plant protein-stabilized emulsions, the influence of the non-protein components also needs to be considered. Many food emulsions, such as mayonnaise or infant formula, are stabilized by not only proteins, but also phospholipids. Such an interfacial protein-phospholipid combination can also be found in oleosomes, natural lipid droplets which show a high oxidative stability. This stability has been attributed to their interfacial architecture in which oleosins and phospholipids form a tight physical barrier against pro-oxidant species. However, while the antioxidant properties of proteins are widely reported, the contribution of phospholipids to lipid oxidation in plant protein-based emulsions remains underexplored.
In this work, we investigated how mixed interfacial plant proteins and phospholipids may be rationally used to control the oxidative stability of O/W emulsions. The interfacial composition was modulated by varying the ratio between pea proteins and sunflower phosphatidylcholine (PC) while keeping the total concentration of pea proteins constant. Increasing the phospholipid-to-protein ratio led to a monotonic decrease in the concentration of proteins and an increase of phospholipids at the interface, while the oxidative stability of those O/W emulsions changed in a non-monotonic pattern. The results were put in perspective by embedding them in a context of reviewing the potential implications of typical components in plant protein ingredients on lipid oxidation.
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Durand, Erwann, Nastassia Kaugarenia, Nathalie Barouh, Pierre Villeneuve e Romain Kapel. "Antioxidant chelating peptides production from Rapeseed meal proteins proteolysis." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/whcd7145.
Testo completoAbstract (sommario):
The oxidative chemical degradation produced by reactive species (free radicals, oxygen, etc.) is responsible for the deterioration of most of the formulated products. One of the main properties of an antioxidant lies in its capacity to limit the chemical propagation of oxidation by reducing free radicals. Another strategy to prevent oxidation is binding transition metals, since they are ubiquitous and deeply involved in the initiation and propagation of lipids oxidation. Naturally occurring phospholipids, polyphenols, proteins, or peptides that can bind metal ions could be more valued than synthetic molecules, for human wellbeing, but also to align with consumer preferences. Yet, EDTA salts and sodium citrate remain the most common metal chelators in foods. In this study, we went to investigate a strategy to develop naturally produced antioxidants peptides from edible plant biomass, such as rapeseed. Several enzymatic hydrolyses of total rapeseed protein isolate with various proteases have been performed, and the produced peptides were screened for their antioxidant capacity. Peptides generated with Prolyve® allowed for particularly high Fe2+ chelation capacity (EC50 = 247 ± 27 µg). Accordingly, the enzymatic processing step with Prolyve® was modeled and optimized to minimize reaction costs and maximize peptide recovery. Then, lipid oxidation was studied in the presence or in the absence of chelating peptides, in micellar, bulk, and oil-in-water emulsion systems, and compared with EDTA salts and sodium citrate. Results clearly emphasized a very interesting potential from the peptides sample to prevent lipid oxidation by chelation of transition metals in emulsified models.This result is particularly important to develop the potential of applications of rapeseed meal in various food formulations. In addition, this study emphasized an approach aiming at developing food chelator peptides from plant proteins, having multifunctional properties, and through sustainable processing.
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Zhang, Jingnan, Bovie Hong, Mehdi Abdollahi, Marie Alminger e Ingrid Undeland. "Lingonberry Press-cake Inhibits Lipid Oxidation During Ph-shift Processing of Herring Co-products and Subsequent Ice Storage of Recovered Protein Isolates". In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/ztsa6947.
Testo completoAbstract (sommario):
Lipid oxidation has been reported as a problem when recovering functional proteins from herring filleting co-products using the pH-shift method. Motivated by the wish for clean label and sustainable development within the food industry, we have earlier shown good oxidation-inhibiting potential when adding 30% (dw/dw) of seven different antioxidant-containing underutilized materials including agricultural/shellfish side streams and seaweeds, both during processing and during subsequent ice storage of protein isolates. Lingonberry press-cake has been recognized as the most promising. However, at 30% addition, it reduced protein yields, increased consumption of base, and dramatically changed the color and texture of protein isolates. Here, we investigated how reducing the lingonberry press-cake addition from 30% to 2.5% affected protein yields and base consumption during processing as well as lipid-oxidative stability, composition and appearance of protein isolates. < ![if !supportLineBreakNewLine] > < ![endif] >Aligned with our hypothesis, lower lingonberry addition yielded increased protein yields, reduced base consumption and lightened color of protein isolates. The results of hexenal, heptanal and octanal revealed that 2.5% addition of lingonberry press-cake efficiently limited lipid oxidation during pH-shift processing, and 10% was enough to also prevent the formation of above-mentioned volatile aldehydes during 7 days of ice storage. Based on the wish of higher protein yield and saving base while at the same time avoiding lipid oxidation, combining herring filleting co-products with 10% lingonberry press cake (dw/dw) was recognized as a very promising raw material combination for new types of protein isolates which will be subject for further studies.
4
Lamsal, Buddhi, e Md Mahfuzur Rahman. "Conventional and novel technologies for extraction of protein and their impact on structure and functionality as ingredient". In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/dhxf1174.
Testo completoAbstract (sommario):
Proteins possess their techno-functionalities by virtues of their state of being, i.e., their molecular makeup and structure, which in turn, is affected by the technologies employed to extract them from the matrices they belong to. This is true for both plant proteins and cell-based proteins. While pH-modulated solubility based aqueous extraction, followed by isolation, is the overwhelming method for plant protein preparations, other technologies, for example dry fractionation (separation based on density, air drag or electrostatic charges), enzyme-, microwave-, ultrasound-, pulsed electric energy- and high pressure-assisted extraction, subcritical water, reverse micelles extraction, and aqueous two-phase systems extraction have been researched for better yields and functionality. Physical separation or dry fractionation preserves the molecular structure and protein possesses better techno-functional and sensory properties than conventional alkaline and acid-based methods. However, dry fractionation can produce only protein concentrate, not isolate. Although alkaline and acid-based methods can prepare to isolate efficiently, subsequent acid precipitation and drying methods form insoluble aggregates and enhance oxidation, which in turn, affect solubility and related functional properties as well as contribute to off-flavor. This presentation will summarize such technologies for extraction, potential for sustainability and their impact on protein's structure and techno-functionalities such as solubility, foaming/emulsion, gelation etc. It will also present authors' recent research on ultrasound-assisted extraction of soy protein and changes in major isolate structure/ function.
5
Yang, Hongshun, Xiao Feng e Zhongyang Ren. "Developing Pickering and nanoemulsions for inhibiting lipid oxidation of aquatic food products". In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/vcyj7544.
Testo completoAbstract (sommario):
Emulsions including Pickering emulsions and nanoemulsions have enormous application potential for inhibiting lipid oxidation. Polysaccharides like κ-carrageenan can improve the gel-like behavior of protein-stabilized Pickering emulsions. Tea water-insoluble proteins and κ-carrageenan can be used for preparing fish oil-in-water Pickering emulsions and fish oil gels. The characteristics of Pickering emulsions and fish oil gels at different proportion of tea water-insoluble proteins and κ-carrageenan were analyzed by high-speed homogenization assisted with ultrasonic treatment. The physicochemical analysis and secondary structure of mixtures showed that the turbidity reduced, particle size unchanged except that of mixtures at 80:20 and zeta potential was unaltered with the addition of κ-carrageenan; meanwhile, the secondary structure of mixtures changed due to the addition of κ-carrageenan. The viscoelastic behavior enhanced compared with that stabilized by tea water-insoluble proteins only. Fish oil gels using mixture-stabilized PEs as a template had a solid-like behavior with a storage modulus of approximately 200 kPa. Besides, the effects of tocopherol nanoemulsions on lipid oxidation of fish sausages were assessed during 16-day storage at 4€¯°C. Nanoemulsions including 250 and 500€¯mg/kg tocopherol improved fish sausages' quality during cold storage and effectively inhibited lipid oxidation due to low peroxide value and high polyunsaturated fatty acid content. The droplet diameter of nanoemulsions including tocopherol stored at 4€¯°C for 16 days was below 500€¯nm. The small droplets with even distribution, and high stability of tocopherol nanoemulsions might explain the potential mechanism of inhibiting lipid oxidation in fish sausages. Interestingly, nanoemulsions encapsulated with 250€¯mg/kg tocopherol were effective to delay the lipid oxidation and improve fish sausages quality during cold storage. These findings will be useful for developing new edible hydrocolloid systems such as Pickering emulsions and nanoemulsions to inhibit lipid oxidation in aquatic products and broaden the application of emulsions in food industry.
6
Wang, Yixiang, Bin Li, Shilin Liu, Xiaogang Luo, Xingzhong Zhang e Yan Li. "Pickering emulsions stabilized by soybean protein isolate/cellulose nanofibrils: Influence of pH". In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/zksv4215.
Testo completoAbstract (sommario):
Emulsions including Pickering emulsions and nanoemulsions have enormous application potential for inhibiting lipid oxidation. Polysaccharides like κ-carrageenan can improve the gel-like behavior of protein-stabilized Pickering emulsions. Tea water-insoluble proteins and κ-carrageenan can be used for preparing fish oil-in-water Pickering emulsions and fish oil gels. The characteristics of Pickering emulsions and fish oil gels at different proportion of tea water-insoluble proteins and κ-carrageenan were analyzed by high-speed homogenization assisted with ultrasonic treatment. The physicochemical analysis and secondary structure of mixtures showed that the turbidity reduced, particle size unchanged except that of mixtures at 80:20 and zeta potential was unaltered with the addition of κ-carrageenan; meanwhile, the secondary structure of mixtures changed due to the addition of κ-carrageenan. The viscoelastic behavior enhanced compared with that stabilized by tea water-insoluble proteins only. Fish oil gels using mixture-stabilized PEs as a template had a solid-like behavior with a storage modulus of approximately 200 kPa. Besides, the effects of tocopherol nanoemulsions on lipid oxidation of fish sausages were assessed during 16-day storage at 4 °C. Nanoemulsions including 250 and 500 mg/kg tocopherol improved fish sausages’ quality during cold storage and effectively inhibited lipid oxidation due to low peroxide value and high polyunsaturated fatty acid content. The droplet diameter of nanoemulsions including tocopherol stored at 4 °C for 16 days was below 500 nm. The small droplets with even distribution, and high stability of tocopherol nanoemulsions might explain the potential mechanism of inhibiting lipid oxidation in fish sausages. Interestingly, nanoemulsions encapsulated with 250 mg/kg tocopherol were effective to delay the lipid oxidation and improve fish sausages quality during cold storage. These findings will be useful for developing new edible hydrocolloid systems such as Pickering emulsions and nanoemulsions to inhibit lipid oxidation in aquatic products and broaden the application of emulsions in food industry.
7
Turrens, Julio F., Eric Robinson, Scott Freeman e Benedict F. George III. "Spectral analysis of light emitted during the oxidation of lipids and proteins". In Medical Imaging 2003, a cura di Anne V. Clough e Amir A. Amini. SPIE, 2003. http://dx.doi.org/10.1117/12.480409.
Testo completo
8
Kaugarenia, Nastassia, Sophie Beaubier, Erwann Durand, François Lesage, Xavier Framboisier, Arnaud Aymes, Pierre Villeneuve e Romain Kapel. "Optimization of Potent Mineral Chelating Peptides Production from Rapeseed Meal Proteins Proteolysis and Peptide Characterizations". In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/ougk6662.
Testo completoAbstract (sommario):
Preventing lipid oxidation and microbial spoilage are both major concerns in sectors such as food and cosmetic industries. Biopeptides, arouse great interest to substitute synthetic antioxidants. Some plant proteins, like 2S rapeseed albumins are known presenting antimicrobial properties. In this context, we aimed to valorize total rapeseed meal proteins with controlled enzymatic proteolysis to generate mineral chelating peptides from the 11S globulins fraction while keeping intact the albumins fraction. To do so, screening of proteases on total rapeseed protein isolate was implemented highlighting a globulin-selective hydrolysis with Prolyve®. Ultrafiltration was then used to purified albumins and enrich the peptide fraction. The fraction obtained showed a noteworthy metal chelating activity. Then, the selected proteolysis was optimized in order to maximize the albumins purity and yield. For that, enzymatic mechanism identification in a wide operating conditions area was led to define the DoE. Then, simulation of hydrolysis kinetics was driven to predict protein fractions concentration at any time and any set of operation conditions. The obtained models were implemented in a genetic-evolutionary algorithm to generate the Pareto Front and Domain, presenting the targeted economical compromises. One solution was chosen and the identified corresponding operating conditions proved the metal chelating activity conservation (EC50 = 247 ± 27 µg) for three times faster production at the same enzyme cost. Finally, peptide activity was investigated in oil-in-water emulsion systems and compared with EDTA. Results showed that peptides could be as effective as EDTA to avoid primary and secondary lipid oxidation products formation.This work demonstrates an original total valorization of both rapeseed meal proteins in food applications. First, antioxidant peptides produced from the globulin fraction, could be used as food preservative in oil-in-water emulsion systems, but also as preventing agents for micronutrient deficiencies. And, the purified albumin fraction could be used to prevent microbial spoilage.
9
Lopez-Garcia, Guillermo, Jose M. Jerez, Daniel Urda e Francisco J. Veredas. "MetODeep: A Deep Learning Approach for Prediction of Methionine Oxidation Sites in Proteins". In 2019 International Joint Conference on Neural Networks (IJCNN). IEEE, 2019. http://dx.doi.org/10.1109/ijcnn.2019.8851901.
Testo completo
10
Phelps, DS, TM Umstead, WM Freeman e VM Chinchilli. "Age-Related Changes in the Expression and Oxidation of Bronchoalveolar Lavage Proteins in the Rat." In American Thoracic Society 2009 International Conference, May 15-20, 2009 • San Diego, California. American Thoracic Society, 2009. http://dx.doi.org/10.1164/ajrccm-conference.2009.179.1_meetingabstracts.a1967.
Testo completoRapporti di organizzazioni sul tema "Proteins Oxidation"
1
Kanner, Joseph, Mark Richards, Ron Kohen e Reed Jess. Improvement of quality and nutritional value of muscle foods. United States Department of Agriculture, dicembre 2008. http://dx.doi.org/10.32747/2008.7591735.bard.
Testo completoAbstract (sommario):
Food is an essential to our existence but under certain conditions it could become the origin to the accumulative health damages. Technological processes as heating, chopping, mincing, grounding, promote the lipid oxidation process in muscle tissues and meat foodstuffs. Lipid oxidation occurred rapidly in turkey muscle, intermediate in duck, and slowest in chicken during frozen storage. Depletion of tocopherol during frozen storage was more rapid in turkey and duck compared to chicken. These processes developed from lipid peroxides produce many cytotoxic compounds including malondialdehyde (MDA). The muscle tissue is further oxidized in stomach conditions producing additional cytotoxic compounds. Oxidized lipids that are formed during digestion of a meal possess the potential to promote reactions that incur vascular diseases. A grape seed extract (1% of the meat weight) and butylated hydroxytoluene (0.2% of the lipid weight) were each effective at preventing formation of lipid oxidation products for 3 hours during co-incubation with cooked turkey meat in simulated gastric fluid (SGF). Polyphenols in the human diet, as an integral part of the meal prevent the generation and absorption of cytotoxic compounds and the destruction of essential nutrients, eg. antioxidants vitamins during the meal. Polyphenols act as antioxidants in the gastrointestinal tract; they scavenge free radicals and may interact with reactive carbonyls, enzymes and proteins. These all reactions results in decreasing the absorption of reactive carbonyls and possible other cytotoxic compounds into the plasma. Consumptions of diet high in fat and red meat are contributory risk factors partly due to an increase production of cytotoxic oxidized lipid products eg. MDA. However, the simultaneously consumption of polyphenols rich foods reduce these factors. Locating the biological site of action of polyphenols in the in the gastrointestinal tract may explain the paradox between the protective effect of a highly polyphenols rich diet and the low bioavailability of these molecules in human plasma. It may also explain the "French paradox" and the beneficial effect of Mediterranean and Japanese diets, in which food products with high antioxidants content such as polyphenols are consumed during the meal.
2
Ohad, Itzhak, e Himadri Pakrasi. Role of Cytochrome B559 in Photoinhibition. United States Department of Agriculture, dicembre 1995. http://dx.doi.org/10.32747/1995.7613031.bard.
Testo completoAbstract (sommario):
The aim of this research project was to obtain information on the role of the cytochrome b559 in the function of Photosystem-II (PSII) with special emphasis on the light induced photo inactivation of PSII and turnover of the photochemical reaction center II protein subunit RCII-D1. The major goals of this project were: 1) Isolation and sequencing of the Chlamydomonas chloroplast psbE and psbF genes encoding the cytochrome b559 a and b subunits respectively; 2) Generation of site directed mutants and testing the effect of such mutation on the function of PSII under various light conditions; 3) To obtain further information on the mechanism of the light induced degradation and replacement of the PSII core proteins. This information shall serve as a basis for the understanding of the role of the cytochrome b559 in the process of photoinhibition and recovery of photosynthetic activity as well as during low light induced turnover of the D1 protein. Unlike in other organisms in which the psbE and psbF genes encoding the a and b subunits of cytochrome b559, are part of an operon which also includes the psbL and psbJ genes, in Chlamydomonas these genes are transcribed from different regions of the chloroplast chromosome. The charge distribution of the derived amino-acid sequences of psbE and psbF gene products differs from that of the corresponding genes in other organisms as far as the rule of "positive charge in" is concerned relative to the process of the polypeptide insertion in the thylakoid membrane. However, the sum of the charges of both subunits corresponds to the above rule possibly indicating co-insertion of both subunits in the process of cytochrome b559 assembly. A plasmid designed for the introduction of site-specific mutations into the psbF gene of C. reinhardtii. was constructed. The vector consists of a DNA fragment from the chromosome of C. reinhardtii which spans the region of the psbF gene, upstream of which the spectinomycin-resistance-conferring aadA cassette was inserted. This vector was successfully used to transform wild type C. reinhardtii cells. The spectinomycin resistant strain thus obtained can grow autotrophically and does not show significant changes as compared to the wild-type strain in PSII activity. The following mutations have been introduced in the psbF gene: H23M; H23Y; W19L and W19. The replacement of H23 involved in the heme binding to M and Y was meant to permit heme binding but eventually alter some or all of the electron transport properties of the mutated cytochrome. Tryptophane W19, a strictly conserved residue, is proximal to the heme and may interact with the tetrapyrole ring. Therefore its replacement may effect the heme properties. A change to tyrosine may have a lesser affect on the potential or electron transfer rate while a replacement of W19 by leucine is meant to introduce a more prominent disturbance in these parameters. Two of the mutants, FW19L and FH23M have segregated already and are homoplasmic. The rest are still grown under selection conditions until complete segregation will be obtained. All mutants contain assembled and functional PSII exhibiting an increased sensitivity of PSII to the light. Work is still in progress for the detailed characterization of the mutants PSII properties. A tobacco mutant, S6, obtained by Maliga and coworkers harboring the F26S mutation in the b subunit was made available to us and was characterized. Measurements of PSII charge separation and recombination, polypeptide content and electron flow indicates that this mutation indeed results in light sensitivity. Presently further work is in progress in the detailed characterization of the properties of all the above mutants. Information was obtained demonstrating that photoinactivation of PSII in vivo initiates a series of progressive changes in the properties of RCII which result in an irreversible modification of the RCII-D1 protein leading to its degradation and replacement. The cleavage process of the modified RCII-D1 protein is regulated by the occupancy of the QB site of RCII by plastoquinone. Newly synthesized D1 protein is not accumulated in a stable form unless integrated in reassembled RCII. Thus the degradation of the irreversibly modified RCII-D1 protein is essential for the recovery process. The light induced degradation of the RCII-D1 protein is rapid in mutants lacking the pD1 processing protease such as in the LF-1 mutant of the unicellular alga Scenedesmus obliquus. In this case the Mn binding site of PSII is abolished, the water oxidation process is inhibited and harmful cation radicals are formed following light induced electron flow in PSII. In such mutants photo-inactivation of PSII is rapid, it is not protected by ligands binding at the QB site and the degradation of the inactivated RCII-D1 occurs rapidly also in the dark. Furthermore the degraded D1 protein can be replaced in the dark in absence of light driven redox controlled reactions. The replacement of the RCII-D1 protein involves the de novo synthesis of the precursor protein, pD1, and its processing at the C-terminus end by an unknown processing protease. In the frame of this work, a gene previously isolated and sequenced by Dr. Pakrasi's group has been identified as encoding the RCII-pD1 C-terminus processing protease in the cyanobacterium Synechocystis sp. PCC 6803. The deduced sequence of the ctpA protein shows significant similarity to the bovine, human and insect interphotoreceptor retinoid-binding proteins. Results obtained using C. reinhardtii cells exposes to low light or series of single turnover light flashes have been also obtained indicating that the process of RCII-D1 protein turnover under non-photoinactivating conditions (low light) may be related to charge recombination in RCII due to back electron flow from the semiquinone QB- to the oxidised S2,3 states of the Mn cluster involved in the water oxidation process.
3
Fluhr, Robert, e Maor Bar-Peled. Novel Lectin Controls Wound-responses in Arabidopsis. United States Department of Agriculture, gennaio 2012. http://dx.doi.org/10.32747/2012.7697123.bard.
Testo completoAbstract (sommario):
Innate immune responses in animals and plants involve receptors that recognize microbe-associated molecules. In plants, one set of this defense system is characterized by large families of TIR–nucleotide binding site–leucine-rich repeat (TIR-NBS-LRR) resistance genes. The direct interaction between plant proteins harboring the TIR domain with proteins that transmit and facilitate a signaling pathway has yet to be shown. The Arabidopsis genome encodes TIR-domain containing genes that lack NBS and LRR whose functions are unknown. Here we investigated the functional role of such protein, TLW1 (TIR LECTIN WOUNDRESPONSIVE1). The TLW1 gene encodes a protein with two domains: a TIR domain linked to a lectin-containing domain. Our specific aim in this proposal was to examine the ramifications of the TL1-glycan interaction by; A) The functional characterization of TL1 activity in the context of plant wound response and B) Examine the hypothesis that wounding induced specific polysaccharides and examine them as candidates for TL-1 interactive glycan compounds. The Weizmann group showed TLW1 transcripts are rapidly induced by wounding in a JA-independent pathway and T-DNA-tagged tlw1 mutants that lack TLW1 transcripts, fail to initiate the full systemic wound response. Transcriptome methodology analysis was set up and transcriptome analyses indicates a two-fold reduced level of JA-responsive but not JA-independent transcripts. The TIR domain of TLW1 was found to interact directly with the KAT2/PED1 gene product responsible for the final b-oxidation steps in peroxisomal-basedJA biosynthesis. To identify potential binding target(s) of TL1 in plant wound response, the CCRC group first expressed recombinant TL1 in bacterial cells and optimized conditions for the protein expression. TL1 was most highly expressed in ArcticExpress cell line. Different types of extraction buffers and extraction methods were used to prepare plant extracts for TL1 binding assay. Optimized condition for glycan labeling was determined, and 2-aminobenzamide was used to label plant extracts. Sensitivity of MALDI and LC-MS using standard glycans. THAP (2,4,6- Trihydroxyacetophenone) showed minimal background peaks at positive mode of MALDI, however, it was insensitive with a minimum detection level of 100 ng. Using LC-MS, sensitivity was highly increased enough to detect 30 pmol concentration. However, patterns of total glycans displayed no significant difference between different extraction conditions when samples were separated with Dionex ICS-2000 ion chromatography system. Transgenic plants over-expressing lectin domains were generated to obtain active lectin domain in plant cells. Insertion of the overexpression construct into the plant genome was confirmed by antibiotic selection and genomic DNA PCR. However, RT-PCR analysis was not able to detect increased level of the transcripts. Binding ability of azelaic acid to recombinant TL1. Azelaic acid was detected in GST-TL1 elution fraction, however, DHB matrix has the same mass in background signals, which needs to be further tested on other matrices. The major findings showed the importance of TLW1 in regulating wound response. The findings demonstrate completely novel and unexpected TIR domain interactions and reveal a control nexus and mechanism that contributes to the propagation of wound responses in Arabidopsis. The implications are to our understanding of the function of TIR domains and to the notion that early molecular events occur systemically within minutes of a plant sustaining a wound. A WEB site (http://genome.weizmann.ac.il/hormonometer/) was set up that enables scientists to interact with a collated plant hormone database.
4
Xiao, Shan, Wan Gang Zhang, Eun Joo Lee e Dong U. Ahn. Lipid and Protein Oxidation of Chicken Breast Rolls as Affected by Dietary Oxidation Levels and Packaging. Ames (Iowa): Iowa State University, gennaio 2013. http://dx.doi.org/10.31274/ans_air-180814-631.
Testo completo
5
Xiao, Shan, Wan Gang Zhang, Eun Joo Lee e Dong U. Ahn. Effects of Diet, Packaging and Irradiation on Protein Oxidation, Lipid Oxidation of Raw Broiler Thigh Meat. Ames (Iowa): Iowa State University, gennaio 2013. http://dx.doi.org/10.31274/ans_air-180814-728.
Testo completo
6
Landau, Sergei Yan, John W. Walker, Avi Perevolotsky, Eugene D. Ungar, Butch Taylor e Daniel Waldron. Goats for maximal efficacy of brush control. United States Department of Agriculture, marzo 2008. http://dx.doi.org/10.32747/2008.7587731.bard.
Testo completoAbstract (sommario):
Background. Brush encroachment constitutes a serious problem in both Texas and Israel. We addressed the issue of efficacy of livestock herbivory - in the form of goat browsing - to change the ecological balance to the detriment of the shrub vegetation. Shrub consumption by goats is kept low by plant chemical defenses such as tannins and terpenes. Scientists at TAES and ARO have developed an innovative, cost-effective methodology using fecal Near Infrared Spectrometry to elucidate the dietary percentage of targeted, browse species (terpene-richredberry and blueberry juniper in the US, and tannin-rich Pistacialentiscus in Israel) for a large number of animals. The original research objectives of this project were: 1. to clarify the relative preference of goat breeds and the individual variation of goats within breeds, when consuming targeted brush species; 2. to assess the heritability of browse intake and validate the concept of breeding goat lines that exhibit high preference for chemically defended brush, using juniper as a model; 3. to clarify the relative contributions of genetics and learning on the preference for target species; 4. to identify mechanisms that are associated with greater intake of brush from the two target species; 5. to establish when the target species are the most vulnerable to grazing. (Issue no.5 was addressed only partly.) Major conclusions, solutions, achievements: Both the Israel and US scientists put significant efforts into improving and validating the technique of Fecal NIRS for predicting the botanical composition of goat diets. Israeli scientists validated the use of observational data for calibrating fecal NIRS, while US scientists established that calibrations could be used across animals differing in breed and age but that caution should be used in making comparisons between different sexes. These findings are important because the ability to select goat breeds or individuals within a breed for maximal efficiency of brush control is dependent upon accurate measurement of the botanical composition of the diet. In Israel it was found that Damascus goats consume diets more than twice richer in P. lentiscus than Mamber or Boer goats. In the US no differences were found between Angora and Boer cross goats but significant differences were found between individuals within breeds in juniper dietary percentage. In both countries, intervention strategies were found that further increased the consumption of the chemically defended plant. In Israel feeding polyethylene glycol (PEG, MW 4,000) that forms high-affinity complexes with tannins increased P. lentiscus dietary percentage an average of 7 percentage units. In the US feeding a protein supplement, which enhances rates of P450-catalyzed oxidations and therefore the rate of oxidation of monoterpenes, increased juniper consumption 5 percentage units. However, the effects of these interventions were not as large as breed or individual animal effects. Also, in a wide array of competitive tannin-binding assays in Israel with trypsin, salivary proteins did not bind more tannic acid or quebracho tannin than non-specific bovine serum albumin, parotid saliva did not bind more tannins than mixed saliva, no response of tannin-binding was found to levels of dietary tannins, and the breed effect was of minor importance, if any. These fundings strongly suggest that salivary proteins are not the first line of defense from tannin astringency in goats. In the US relatively low values for heritability and repeatability for juniper consumption were found (13% and 30%, respectively), possibly resulting from sampling error or non-genetic transfer of foraging behavior, i.e., social learning. Both alternatives seem to be true as significant variation between sequential observations were noted on the same animal and cross fostering studies conducted in Israel demonstrated that kids raised by Mamber goats showed lower propensity to consume P. lentiscus than counterparts raised by Damascus goats.
7
Droby, Samir, Michael Wisniewski, Ron Porat e Dumitru Macarisin. Role of Reactive Oxygen Species (ROS) in Tritrophic Interactions in Postharvest Biocontrol Systems. United States Department of Agriculture, dicembre 2012. http://dx.doi.org/10.32747/2012.7594390.bard.
Testo completoAbstract (sommario):
To elucidate the role of ROS in the tri-trophic interactions in postharvest biocontrol systems a detailed molecular and biochemical investigation was undertaken. The application of the yeast biocontrol agent Metschnikowia fructicola, microarray analysis was performed on grapefruit surface wounds using an Affymetrix Citrus GeneChip. the data indicated that 1007 putative unigenes showed significant expression changes following wounding and yeast application relative to wounded controls. The expression of the genes encoding Respiratory burst oxidase (Rbo), mitogen-activated protein kinase (MAPK) and mitogen-activated protein kinase kinase (MAPKK), G-proteins, chitinase (CHI), phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS) and 4-coumarate-CoA ligase (4CL). In contrast, three genes, peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT), were down-regulated in grapefruit peel tissue treated with yeast cells. The yeast antagonists, Metschnikowia fructicola (strain 277) and Candida oleophila (strain 182) generate relatively high levels of super oxide anion (O2−) following its interaction with wounded fruit surface. Using laser scanning confocal microscopy we observed that the application of M. fructicola and C. oleophila into citrus and apple fruit wounds correlated with an increase in H2O2 accumulation in host tissue. The present data, together with our earlier discovery of the importance of H₂O₂ production in the defense response of citrus flavedo to postharvest pathogens, indicate that the yeast-induced oxidative response in fruit exocarp may be associated with the ability of specific yeast species to serve as biocontrol agents for the management of postharvest diseases. Effect of ROS on yeast cells was also studied. Pretreatment of the yeast, Candida oleophila, with 5 mM H₂O₂ for 30 min (sublethal) increased yeast tolerance to subsequent lethal levels of oxidative stress (50 mM H₂O₂), high temperature (40 °C), and low pH (pH 4). Suppression subtractive hybridization analysis was used to identify genes expressed in yeast in response to sublethal oxidative stress. Transcript levels were confirmed using semi quantitative reverse transcription-PCR. Seven antioxidant genes were up regulated. Pretreatment of the yeast antagonist Candida oleophila with glycine betaine (GB) increases oxidative stress tolerance in the microenvironment of apple wounds. ROS production is greater when yeast antagonists used as biocontrol agents are applied in the wounds. Compared to untreated control yeast cells, GB-treated cells recovered from the oxidative stress environment of apple wounds exhibited less accumulation of ROS and lower levels of oxidative damage to cellular proteins and lipids. Additionally, GB-treated yeast exhibited greater biocontrol activity against Penicillium expansum and Botrytis cinerea, and faster growth in wounds of apple fruits compared to untreated yeast. The expression of major antioxidant genes, including peroxisomal catalase, peroxiredoxin TSA1, and glutathione peroxidase was elevated in the yeast by GB treatment. A mild heat shock (HS) pretreatment (30 min at 40 1C) improved the tolerance of M. fructicola to subsequent high temperature (45 1C, 20–30 min) and oxidative stress (0.4 mol-¹) hydrogen peroxide, 20–60 min). HS-treated yeast cells showed less accumulation of reactive oxygen species (ROS) than non-treated cells in response to both stresses. Additionally, HS-treated yeast exhibited significantly greater (P≥0.0001) biocontrol activity against Penicillium expansum and a significantly faster (Po0.0001) growth rate in wounds of apple fruits stored at 25 1C compared with the performance of untreated yeast cells. Transcription of a trehalose-6-phosphate synthase gene (TPS1) was up regulated in response to HS and trehalose content also increased.
8
Madaeva, I. M., N. A. Kurashova, N. V. Semenova, E. B. Uhinov, S. I. Kolesnikov e L. I. Kolesnikova. HSP70 HEAT SHOCK PROTEIN IN OXIDATIVE STRESS APNEA PATIENTS. Publishing house of the Russian Academy of Medical Sciences, 2020. http://dx.doi.org/10.18411/1695-1978-2020-62730.
Testo completo
9
Kanner, Joseph, Edwin Frankel, Stella Harel e Bruce German. Grapes, Wines and By-products as Potential Sources of Antioxidants. United States Department of Agriculture, gennaio 1995. http://dx.doi.org/10.32747/1995.7568767.bard.
Testo completoAbstract (sommario):
Several grape varieties and red wines were found to contain large concentration of phenolic compounds which work as antioxidant in-vitro and in-vivo. Wastes from wine production contain antioxidants in large amounts, between 2-6% on dry material basis. Red wines but also white wines were found to prevent lipid peroxidation of turkey muscle tissues stored at 5oC. The antioxidant reaction of flavonoids found in red wines against lipid peroxidation were found to depend on the structure of the molecule. Red wine flavonoids containing an orthodihydroxy structure around the B ring were found highly active against LDL and membrane lipid peroxidation. The antioxidant activity of red wine polyphenols were also found to be dependent on the catalyzer used. In the presence of H2O2-activated myoglobin, the inhibition efficiency was malvidin 3-glucoside>catechin>malvidin>resveratol. However, in the presence of an iron redox cycle catalyzer, the order of effectiveness was resveratol>malvidin 3-glucoside = malvidin>catechin. Differences in protein binding were found to affect antioxidant activity in inhibiting LDL oxidation. A model protein such as BSA, was investigated on the antioxidant activity of phenolic compounds, grape extracts, and red wines in a lecithin-liposome model system. Ferulic acid followed by malvidin and rutin were the most efficient in inhibiting both lipid and protein oxidation. Catechin, a flavonal found in red-wines in relatively high concentration was found to inhibit myoglobin catalyzed linoleate membrane lipid peroxidation at a relatively very low concentration. This effect was studied by the determination of the by-products generated from linoleate during oxidation. The study showed that hydroperoxides are catalytically broken down, not to an alcohol but most probably to a non-radical adduct. The ability of wine-phenolics to reduce iron and from complexes with metals were also demonstrated. Low concentration of wine phenolics were found to inhibit lipoxygenase type II activity. An attempt to understand the bioavailability in humans of antocyanins from red wine showed that two antocyanins from red wine were found unchanged in human urine. Other antocyanins seems to undergo molecular modification. In hypercholesterolemic hamsters, aortic lipid deposition was significantly less in animals fed diets supplemented with either catechin or vitamin E. The rate of LDL accumulation in the carotid arteries was also significantly lower in the catechin and vitamin E animal groups. These results suggested a novel mechanism by which wine phenolics are associated with decreased risk of coronary heart diseases. This study proves in part our hypothesis that the "French Paradox" could be explained by the action of the antioxidant effects of phenolic compounds found at high concentration in red wines. The results of this study argue that it is in the interest of public health to increase the consumption of dietary plant falvonoids. Our results and these from others, show that the consumption of red wine or plant derived polyphenolics can change the antioxidant tone of animal and human plasma and its isolated components towards oxidative reactions. However, we need more research to better understand bioavailability and the mechanism of how polyphenolics affect health and disease.
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Madaev, I. M., N. A. Kurashova, N. V. Semenova, E. B. Ukhinov, S. I. Kolesnikov e L. I. Kolesnikova. Heat shock protein HSP70 for oxidative stress in patients with apnea. Federal State Budgetary Institution Scientific Center, 2020. http://dx.doi.org/10.18411/1695-2608-2020-62730.
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