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Sample records for advanced oxidized protein

  1. Mass Spectrometry-Based Methods for Identifying Oxidized Proteins in Disease: Advances and Challenges

    PubMed Central

    Verrastro, Ivan; Pasha, Sabah; Tveen Jensen, Karina; Pitt, Andrew R.; Spickett, Corinne M.

    2015-01-01

    Many inflammatory diseases have an oxidative aetiology, which leads to oxidative damage to biomolecules, including proteins. It is now increasingly recognized that oxidative post-translational modifications (oxPTMs) of proteins affect cell signalling and behaviour, and can contribute to pathology. Moreover, oxidized proteins have potential as biomarkers for inflammatory diseases. Although many assays for generic protein oxidation and breakdown products of protein oxidation are available, only advanced tandem mass spectrometry approaches have the power to localize specific oxPTMs in identified proteins. While much work has been carried out using untargeted or discovery mass spectrometry approaches, identification of oxPTMs in disease has benefitted from the development of sophisticated targeted or semi-targeted scanning routines, combined with chemical labeling and enrichment approaches. Nevertheless, many potential pitfalls exist which can result in incorrect identifications. This review explains the limitations, advantages and challenges of all of these approaches to detecting oxidatively modified proteins, and provides an update on recent literature in which they have been used to detect and quantify protein oxidation in disease. PMID:25874603

  2. In Vitro Oxidation of Collagen Promotes the Formation of Advanced Oxidation Protein Products and the Activation of Human Neutrophils.

    PubMed

    Bochi, Guilherme Vargas; Torbitz, Vanessa Dorneles; de Campos, Luízi Prestes; Sangoi, Manuela Borges; Fernandes, Natieli Flores; Gomes, Patrícia; Moretto, Maria Beatriz; Barbisan, Fernanda; da Cruz, Ivana Beatrice Mânica; Moresco, Rafael Noal

    2016-04-01

    The accumulation of advanced oxidation protein products (AOPPs) has been linked to several pathological conditions. Here, we investigated collagen as a potential source for AOPP formation and determined the effects of hypochlorous acid (HOCl)-treated collagen (collagen-AOPPs) on human neutrophil activity. We also assessed whether alpha-tocopherol could counteract these effects. Exposure to HOCl increased the levels of collagen-AOPPs. Collagen-AOPPs also stimulated the production of AOPPs, nitric oxide (NO), superoxide radicals (O2 (-)), and HOCl by neutrophils. Collagen-AOPPs induced apoptosis and decreased the number of viable cells. Alpha-tocopherol prevented the formation of collagen-AOPPs, strongly inhibited the collagen-AOPP-induced production of O2 (-) and HOCl, and increased the viability of neutrophils. Our results suggest that collagen is an important protein that interacts with HOCl to form AOPPs, and consequently, collagen-AOPP formation is related to human neutrophil activation and cell death. PMID:26920846

  3. Fenton Reaction-Generated Advanced Oxidation Protein Products Induces Inflammation in Human Embryonic Kidney Cells.

    PubMed

    Bochi, Guilherme Vargas; Torbitz, Vanessa Dorneles; Santos, Roberto Christ Vianna; Cubillos-Rojas, Monica; López, José Luis Rosa; Siebel, Anna Maria; Gomes, Patrícia; de Oliveira, Jarbas Rodrigues; Moresco, Rafael Noal

    2016-08-01

    Fenton reaction is a new mechanism able to generate advanced oxidation protein products (AOPPs) by exposing the human serum albumin to the Fenton system. Here, we characterized the effects of Fenton reaction-generated advanced oxidation protein products (AOPP-FR) on the gene transcription of the nuclear factor-κB (NF-κB), cyclooxygenase-2 (COX-2), and interleukin-6 (IL-6) in human embryonic kidney cells (HEK 293). To investigate the effects of AOPP-FR and AOPP-HOCl on transcription of inflammatory genes, the NF-κB, COX-2, and IL-6 luciferase promoter activities were analyzed. AOPP-FR and AOPP-HOCl were able to induce the activation of the gene transcription of NF-κB, COX-2, and IL-6 in HEK 293 cells. However, the effects of AOPP-FR were significantly higher than the effects of AOPP-HOCl in relation to COX-2 and IL-6. AOPP-FR induces the activation of the gene transcription of NF-κB, COX-2, and IL-6 and may represent a novel pathogenic mediator of inflammation in kidney. PMID:27145783

  4. Advanced oxidative protein products induced human keratinocyte apoptosis through the NOX-MAPK pathway.

    PubMed

    Sun, Baihui; Ding, Ruoting; Yu, Wenlin; Wu, Yanhong; Wang, Bulin; Li, Qin

    2016-07-01

    Impaired wound healing is a major diabetes-related complication. Keratinocytes play an important role in wound healing. Multiple factors have been proposed that can induce dysfunction in keratinocytes. The focus of present research is at a more specific molecular level. We investigated the role of advanced oxidative protein products (AOPPs) in inducing human immortalized keratinocyte (HaCaT) cell apoptosis and the cellular mechanism underlying the proapoptotic effect of AOPPs. HaCaT cells were treated with increasing concentrations of AOPP-human serum albumin or for increasing time durations. The cell viability was measured using the thiazolyl blue tetrazolium bromide method, and flow cytometry was used to assess the rate of cell apoptosis. A loss of mitochondrial membrane potential (MMP) and an increase in intracellular reactive oxygen species (ROS) were observed through a confocal laser scanning microscope system, and the level of ROS generation was determined using a microplate reader. Nicotinamide adenine dinucleotide phosphate oxidase (NOX)4, extracellular signal-regulated kinase (ERK)1/2, p38 mitogen-activated protein kinase (MAPK), and apoptosis-related downstream protein interactions were investigated using the Western blot analysis. We found that AOPPs triggered HaCaT cell apoptosis and MMP loss. After AOPP treatment, intracellular ROS generation increased in a time- and dose-dependent manner. Proapoptotic proteins, such as Bax, caspase 9/caspase 3, and poly(ADP-ribose) polymerase (PARP)-1 were activated, whereas anti-apoptotic Bcl-2 protein was downregulated. AOPPs also increased NOX4, ERK1/2, and p38 MAPK expression. Taken together, these findings suggest that extracellular AOPP accumulation triggered NOX-dependent ROS production, which activated ERK1/2 and p38 MAPK, and induced HaCaT cell apoptosis by activating caspase 3 and PARP-1. PMID:27155970

  5. UVA Light-excited Kynurenines Oxidize Ascorbate and Modify Lens Proteins through the Formation of Advanced Glycation End Products

    PubMed Central

    Linetsky, Mikhail; Raghavan, Cibin T.; Johar, Kaid; Fan, Xingjun; Monnier, Vincent M.; Vasavada, Abhay R.; Nagaraj, Ram H.

    2014-01-01

    Advanced glycation end products (AGEs) contribute to lens protein pigmentation and cross-linking during aging and cataract formation. In vitro experiments have shown that ascorbate (ASC) oxidation products can form AGEs in proteins. However, the mechanisms of ASC oxidation and AGE formation in the human lens are poorly understood. Kynurenines are tryptophan oxidation products produced from the indoleamine 2,3-dioxygenase (IDO)-mediated kynurenine pathway and are present in the human lens. This study investigated the ability of UVA light-excited kynurenines to photooxidize ASC and to form AGEs in lens proteins. UVA light-excited kynurenines in both free and protein-bound forms rapidly oxidized ASC, and such oxidation occurred even in the absence of oxygen. High levels of GSH inhibited but did not completely block ASC oxidation. Upon UVA irradiation, pigmented proteins from human cataractous lenses also oxidized ASC. When exposed to UVA light (320–400 nm, 100 milliwatts/cm2, 45 min to 2 h), young human lenses (20–36 years), which contain high levels of free kynurenines, lost a significant portion of their ASC content and accumulated AGEs. A similar formation of AGEs was observed in UVA-irradiated lenses from human IDO/human sodium-dependent vitamin C transporter-2 mice, which contain high levels of kynurenines and ASC. Our data suggest that kynurenine-mediated ASC oxidation followed by AGE formation may be an important mechanism for lens aging and the development of senile cataracts in humans. PMID:24798334

  6. 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.

    PubMed

    Fu, S; Fu, M X; Baynes, J W; Thorpe, S R; Dean, R T

    1998-02-15

    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 Nepsilon-(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. PMID:9461515

  7. Enhanced cellular oxidant stress by the interaction of advanced glycation end products with their receptors/binding proteins.

    PubMed

    Yan, S D; Schmidt, A M; Anderson, G M; Zhang, J; Brett, J; Zou, Y S; Pinsky, D; Stern, D

    1994-04-01

    Attack by reactive oxygen intermediates, common to many kinds of cell/tissue injury, has been implicated in the development of diabetic and other vascular diseases. Such oxygen-free radicals can be generated by advanced glycation end products (AGEs), which are nonenzymatically glycated and oxidized proteins. Since cellular interactions of AGEs are mediated by specific cellular binding proteins, receptor for AGE (RAGE) and the lactoferrin-like polypeptide (LF-L), we tested the hypothesis that AGE ligands tethered to the complex of RAGE and LF-L could induce oxidant stress. AGE albumin or AGEs immunoisolated from diabetic plasma resulted in induction of endothelial cell (EC) oxidant stress, including the generation of thiobarbituric acid reactive substances (TBARS) and resulted in the activation of NF-kappa B, each of which was blocked by antibodies to AGE receptor polypeptides and by antioxidants. Infusion of AGE albumin into normal animals led to the appearance of malondialdehyde determinants in the vessel wall and increased TBARS in the tissues, activation of NF-kappa B, and induction of heme oxygenase mRNA. AGE-induced oxidant stress was inhibited by pretreatment of animals with either antibodies to the AGE receptor/binding proteins or antioxidants. These data indicate that interaction of AGEs with cellular targets, such as ECs, leads to oxidant stress resulting in changes in gene expression and other cellular properties, potentially contributing to the development of vascular lesions. Further studies will be required to dissect whether oxidant stress occurs on the cell surface or at an intracellular locus. PMID:8144582

  8. Advanced lipid peroxidation end products in oxidative damage to proteins. Potential role in diseases and therapeutic prospects for the inhibitors

    PubMed Central

    Negre-Salvayre, A; Coatrieux, C; Ingueneau, C; Salvayre, R

    2007-01-01

    Reactive carbonyl compounds (RCCs) formed during lipid peroxidation and sugar glycoxidation, namely Advanced lipid peroxidation end products (ALEs) and Advanced Glycation end products (AGEs), accumulate with ageing and oxidative stress-related diseases, such as atherosclerosis, diabetes or neurodegenerative diseases. RCCs induce the ‘carbonyl stress' characterized by the formation of adducts and cross-links on proteins, which progressively leads to impaired protein function and damages in all tissues, and pathological consequences including cell dysfunction, inflammatory response and apoptosis. The prevention of carbonyl stress involves the use of free radical scavengers and antioxidants that prevent the generation of lipid peroxidation products, but are inefficient on pre-formed RCCs. Conversely, carbonyl scavengers prevent carbonyl stress by inhibiting the formation of protein cross-links. While a large variety of AGE inhibitors has been developed, only few carbonyl scavengers have been tested on ALE-mediated effects. This review summarizes the signalling properties of ALEs and ALE-precursors, their role in the pathogenesis of oxidative stress-associated diseases, and the different agents efficient in neutralizing ALEs effects in vitro and in vivo. The generation of drugs sharing both antioxidant and carbonyl scavenger properties represents a new therapeutic challenge in the treatment of carbonyl stress-associated diseases. PMID:17643134

  9. Decreased melatonin levels and increased levels of advanced oxidation protein products in the seminal plasma are related to male infertility.

    PubMed

    Kratz, Ewa Maria; Piwowar, Agnieszka; Zeman, Michal; Stebelová, Katarína; Thalhammer, Theresia

    2016-03-01

    Melatonin, an indolamine secreted by the pineal gland, is known as a powerful free-radical scavenger and wide-spectrum antioxidant. Therefore, the aim of this study was to correlate markers of oxidative protein damage (advanced oxidation protein products, AOPPs) and the total antioxidant capacity (TAC) with melatonin levels in the seminal plasma of men with azoospermia (n=37), theratozoospermia (n=29) and fertile controls (normozoospermia, n=37). Melatonin concentration was measured by radioimmunoassay. The levels of AOPP as well as TAC efficiency (determined by the ferric reducing antioxidant power, FRAP) were estimated by spectrophotometric methods. The concentration of melatonin and AOPP significantly differed in azoospermic (P<0.0001) and theratozoospermic (P<0.0001) patients versus fertile men, and correlated negatively (r=-0.33, P=0.0016). The TAC levels were significantly higher in azoospermia than in theratozoospermia (P=0.0022) and the control group (P=0.00016). In azoospermia, the AOPP concentration was also significantly higher than that observed in theratozoospermia (P=0.00029). Decreased levels of melatonin together with elevated AOPP altered the oxidative-antioxidative balance in the ejaculate, thereby reducing fertility. Therefore, melatonin and AOPP levels may serve as additional diagnostic markers of semen quality and male reproductive potential. PMID:25218686

  10. May serum levels of advanced oxidized protein products serve as a prognostic marker of disease duration in patients with idiopathic Parkinson's disease?

    PubMed

    García-Moreno, José-Manuel; Martín de Pablos, Angel; García-Sánchez, María-Isabel; Méndez-Lucena, Carolina; Damas-Hermoso, Fátima; Rus, Macarena; Chacón, José; Fernández, Emilio

    2013-04-10

    Protein and amine halogenation is a type of oxidative stress induced by phagocytic overstimulation, and its role in Parkinson's disease (PD) has not been discerned. We have detected that advanced oxidized protein products, markers of protein halogenation, are reliably enhanced in serum of patients with PD (n=60) relative to control subjects (n=45, p<0.012), and to a lesser extent in the cerebrospinal fluid. Amine halogenation, as evaluated through 3-chlorotyrosine, is not affected. Mieloperoxidase and hydrogen peroxide levels, halogenative factors of phagocytes, are devoid of changes. Levels of advanced oxidized protein products are progressively reduced over time, and the duration of PD is larger in the Hoehn-Yahr-stage-2/3 patients (n=34) with low serum levels (R(2)=0.0145, p<0.003). Levodopa treatment contributes to this reduction (R(2)=0.259, p<0.001). These protein products are not cytotoxic, unlike 3-chlorotyrosine, but they are known to form inflammatory mediators after conjugation with serum albumin. Our observations lead to the hypothesis that the serum level of advanced oxidized protein products is a prognostic marker of PD duration, and these oxidized proteins could participate in the development of parkinsonian neurodegeneration. PMID:23121480

  11. Evaluation of Advanced Oxidation Protein Products, Prooxidant-Antioxidant Balance, and Total Antioxidant Capacity in Untreated Vitiligo Patients

    PubMed Central

    Güntaş, Gülcan; Ekmekçi, Özlem Balcı; Kutlubay, Zekayi; Ekmekci, Hakan; Songür, Abdullah; Uzunçakmak, Tuğba Kevser Üstünbaş; Vehid, Hayriye Ertem; Serdaroğlu, Server; Tüzün, Yalçın; Uzun, Hafize

    2015-01-01

    Background Vitiligo is a chronic, common disease of unknown etiology, and oxidative stress is suggested to have a role in its etiopathogenesis. Objective Advanced oxidation protein products (AOPPs), prooxidant-antioxidant balance (PAB), and ferric-reducing antioxidant power (FRAP) were evaluated regarding their role in the pathogenesis of vitiligo as well as their relationship with clinical presentation and disease severity, and these parameters were compared with those of healthy controls. Methods The study included 53 patients with vitiligo and 20 healthy volunteers as the control group. AOPP level, PAB, and FRAP were determined by colorimetric methods. Results PAB and FRAP level were significantly higher in patients with vitiligo than in healthy controls (p<0.001). The AOPP levels in vitiligo patients were not statistically significantly higher than those in healthy controls. The Vitiligo Area Scoring Index positively correlated with disease duration (rs: 0.531, p<0.001). Conclusion To the best of our knowledge, this is the first report of AOPP and PAB status in vitiligo. PAB may be used as an indicator for oxidative stress in the etiopathogenesis of vitiligo. Our results show that these parameters may play a major role in the melanocyte damage observed in vitiligo. Further studies are required to confirm the mechanisms underlying this effect. PMID:25834357

  12. Evaluation of Ischemia-Modified Albumin, Malondialdehyde, and Advanced Oxidative Protein Products as Markers of Vascular Injury in Diabetic Nephropathy

    PubMed Central

    Ahmad, Afzal; Manjrekar, Poornima; Yadav, Charu; Agarwal, Ashish; Srikantiah, Rukmini Mysore; Hegde, Anupama

    2016-01-01

    AIM This study aimed at evaluation of ischemia-modified albumin (IMA), malondialdehyde (MDA), and advanced oxidative protein products (AOPP) as markers of vascular injury in diabetic nephropathy (DN) with derivation of cutoff values for the same. MATERIALS AND METHODS Study population comprised 60 diabetes patients and 30 controls, with diabetes patients further categorized into three groups based on urine albumin/creatinine ratio (UACR) of <30 mg/g (diabetes without microalbuminuria), 30–300 mg/g (early DN), and >300 mg/g of creatinine (overt DN). Serum IMA, MDA, and AOPP were estimated by enzyme-linked immunosorbent assay; HbA1c, serum creatinine, urine albumin, and urine creatinine were estimated using automated analyzers. Statistical analysis was done using analysis of variance, Pearson’s correlation coefficient, and receiver-operating characteristic curve. RESULTS A statistically significant difference was found in the levels of IMA among patients with early DN (154 ng/mL), diabetes without nephropathy (109.4 ng/mL), and healthy controls (45.7 ng/mL), with highest levels in early DN cases. Similar increase was seen in AOPP as well. A significant correlation was observed between IMA and UACR in diabetes without nephropathy (r = 0.448). CONCLUSION The present study postulates serum IMA as a novel biomarker for the assessment of disease progression in diabetes even before microalbuminuria, and a cutoff point ≥99 ng/mL can be used for detection of early DN. PMID:27158221

  13. Protein oxidation and peroxidation.

    PubMed

    Davies, Michael J

    2016-04-01

    Proteins are major targets for radicals and two-electron oxidants in biological systems due to their abundance and high rate constants for reaction. With highly reactive radicals damage occurs at multiple side-chain and backbone sites. Less reactive species show greater selectivity with regard to the residues targeted and their spatial location. Modification can result in increased side-chain hydrophilicity, side-chain and backbone fragmentation, aggregation via covalent cross-linking or hydrophobic interactions, protein unfolding and altered conformation, altered interactions with biological partners and modified turnover. In the presence of O2, high yields of peroxyl radicals and peroxides (protein peroxidation) are formed; the latter account for up to 70% of the initial oxidant flux. Protein peroxides can oxidize both proteins and other targets. One-electron reduction results in additional radicals and chain reactions with alcohols and carbonyls as major products; the latter are commonly used markers of protein damage. Direct oxidation of cysteine (and less commonly) methionine residues is a major reaction; this is typically faster than with H2O2, and results in altered protein activity and function. Unlike H2O2, which is rapidly removed by protective enzymes, protein peroxides are only slowly removed, and catabolism is a major fate. Although turnover of modified proteins by proteasomal and lysosomal enzymes, and other proteases (e.g. mitochondrial Lon), can be efficient, protein hydroperoxides inhibit these pathways and this may contribute to the accumulation of modified proteins in cells. Available evidence supports an association between protein oxidation and multiple human pathologies, but whether this link is causal remains to be established. PMID:27026395

  14. Protein oxidation and peroxidation

    PubMed Central

    Davies, Michael J.

    2016-01-01

    Proteins are major targets for radicals and two-electron oxidants in biological systems due to their abundance and high rate constants for reaction. With highly reactive radicals damage occurs at multiple side-chain and backbone sites. Less reactive species show greater selectivity with regard to the residues targeted and their spatial location. Modification can result in increased side-chain hydrophilicity, side-chain and backbone fragmentation, aggregation via covalent cross-linking or hydrophobic interactions, protein unfolding and altered conformation, altered interactions with biological partners and modified turnover. In the presence of O2, high yields of peroxyl radicals and peroxides (protein peroxidation) are formed; the latter account for up to 70% of the initial oxidant flux. Protein peroxides can oxidize both proteins and other targets. One-electron reduction results in additional radicals and chain reactions with alcohols and carbonyls as major products; the latter are commonly used markers of protein damage. Direct oxidation of cysteine (and less commonly) methionine residues is a major reaction; this is typically faster than with H2O2, and results in altered protein activity and function. Unlike H2O2, which is rapidly removed by protective enzymes, protein peroxides are only slowly removed, and catabolism is a major fate. Although turnover of modified proteins by proteasomal and lysosomal enzymes, and other proteases (e.g. mitochondrial Lon), can be efficient, protein hydroperoxides inhibit these pathways and this may contribute to the accumulation of modified proteins in cells. Available evidence supports an association between protein oxidation and multiple human pathologies, but whether this link is causal remains to be established. PMID:27026395

  15. ADVANCED OXIDATION PROCESS

    SciTech Connect

    Dr. Colin P. Horwitz; Dr. Terrence J. Collins

    2003-11-04

    The removal of recalcitrant sulfur species, dibenzothiophene and its derivatives, from automotive fuels is an integral component in the development of cleaner burning and more efficient automobile engines. Oxidative desulfurization (ODS) wherein the dibenzothiophene derivative is converted to its corresponding sulfoxide and sulfone is an attractive approach to sulfur removal because the oxidized species are easily extracted or precipitated and filtered from the hydrocarbon phase. Fe-TAML{reg_sign} activators of hydrogen peroxide (TAML is Tetra-Amido-Macrocyclic-Ligand) catalytically convert dibenzothiophene and its derivatives rapidly and effectively at moderate temperatures (50-60 C) and ambient pressure to the corresponding sulfoxides and sulfones. The oxidation process can be performed in both aqueous systems containing alcohols such as methanol, ethanol, or t-butanol, and in a two-phase hydrocarbon/aqueous system containing tert-butanol or acetonitrile. In the biphasic system, essentially complete conversion of the DBT to its oxidized products can be achieved using slightly longer reaction times than in homogeneous solution. Among the key features of the technology are the mild reaction conditions, the very high selectivity where no over oxidation of the sulfur compounds occurs, the near stoichiometric use of hydrogen peroxide, the apparent lack of degradation of sensitive fuel components, and the ease of separation of oxidized products.

  16. ADVANCED OXIDATION PROCESS

    SciTech Connect

    Colin P. Horwitz; Terrence J. Collins

    2003-10-22

    The design of new, high efficiency and cleaner burning engines is strongly coupled with the removal of recalcitrant sulfur species, dibenzothiophene and its derivatives, from fuels. Oxidative desulfurization (ODS) wherein these dibenzothiophene derivatives are oxidized to their corresponding sulfoxides and sulfones is an approach that has gained significant attention. Fe-TAML{reg_sign} activators of hydrogen peroxide (TAML is Tetra-Amido-Macrocyclic-Ligand) convert in a catalytic process dibenzothiophene and its derivatives to the corresponding sulfoxides and sulfones rapidly at moderate temperatures (60 C) and ambient pressure. The reaction can be performed in both an aqueous system containing an alcohol (methanol, ethanol, or t-butanol) to solubilize the DBT and in a two-phase hydrocarbon/aqueous system where the alcohol is present in both phases and facilitates the oxidation. Under a consistent set of conditions using the FeBF{sub 2} TAML activator, the degree of conversion was found to be t-butanol > methanol > ethanol. In the cases of methanol and ethanol, both the sulfoxide and sulfone were observed while for t-butanol only the sulfone was detected. In the two-phase system, the alcohol may function as an inverse phase transfer agent. The oxidation was carried out using two different TAML activators. In homogeneous solution, approximately 90% oxidation of the DBT could be achieved using the prototype TAML activator, FeB*, by sonicating the solution at near room temperature. In bi-phasic systems conversions as high as 50% were achieved using the FeB* TAML activator and hydrogen peroxide at 100 C. The sonication method yielded only {approx}6% conversion but this may have been due to mixing.

  17. Sesquiterpene Lactones Inhibit Advanced Oxidation Protein Product-Induced MCP-1 Expression in Podocytes via an IKK/NF-κB-Dependent Mechanism

    PubMed Central

    Zhao, Yan; Chen, Si-jia; Wang, Jian-cheng; Niu, Hong-xin; Jia, Qian-qian; Chen, Xiao-wen; Du, Xiao-yan; Lu, Lu; Huang, Bo; Zhang, Quan; Chen, Yue; Long, Hai-bo

    2015-01-01

    Inflammation is a relevant factor in the pathogenesis of diabetes nephropathy (DN). Sesquiterpene lactones (SLs), originally isolated from Tanacetum parthenium, have been reported to exhibit anti-inflammatory effects but few studies have examined their effects on DN. To determine whether advanced oxidation protein products (AOPPs) can induce the expression of chemokine monocyte chemoattractant protein- (MCP-) 1 in cultured mouse podocytes and to explore the mechanisms of the potential renoprotection of SLs, we treated podocytes with AOPPs and SLs (parthenolide and its derivatives micheliolide, compound 1, and compound 2). MCP-1 mRNA and protein expression were tested using quantitative real-time PCR and ELISA, respectively, and the protein levels of IKKβ, phospho-IKKβ, IκBα, NF-κB p65, phospho-NF-κB p65, and tubulin were analyzed by Western blotting. AOPPs activated the expression of MCP-1 mRNA and protein in a dose- and time-dependent manner, activated IKKβ and NF-κB p65, and promoted IκBα degradation. The IKK/NF-κB inhibitor parthenolide decreased AOPP-induced MCP-1 expression. Pretreatment with SLs inhibited MCP-1 mRNA and protein expression and suppressed IKKβ and NF-κB p65 phosphorylation and IκBα degradation. Taken together, these findings provide a novel explanation for the anti-inflammatory effects of SLs that will ultimately benefit DN and potentially other inflammatory and immune renal diseases. PMID:25664142

  18. Advances in Mechanisms of Anti-oxidation

    PubMed Central

    Ma, Qiang

    2016-01-01

    Reactive oxygen species (ROS) are a family of molecules that are continuously produced from oxygen consumption in aerobic cells. Controlled generation of ROS in normal cells serves useful purposes to regulate important cellular processes such as cell proliferation, inflammation, and immune response, but overproduction of ROS causes oxidative stress that contributes to the development of cancer, chronic disease, and aging. These hugely different consequences of ROS exposure demand a carefully balanced control of ROS production and disposition, which is largely achieved through the body’s elaborate antioxidant system. The human antioxidant system consists of small antioxidants, antioxidant proteins, ROS-metabolizing enzymes, as well as many regulator proteins that mediate adaptive responses to oxidant stress. How such a complex system reacts with oxidants and achieves the required specificity and sensitivity for proper anti-oxidation is incompletely understood. In this respect, new advances in the understanding of the chemistry that determines the reaction of a given oxidant or antioxidant with a protein target provide considerable insights into these and related questions. The findings hold certain promise for new drug development for preventing and treating diseases associated with oxidant tissue damage. PMID:24641954

  19. Advanced oxidation protein products induce endothelial-to-mesenchymal transition in human renal glomerular endothelial cells through induction of endoplasmic reticulum stress.

    PubMed

    Liang, Xiujie; Duan, Na; Wang, Yue; Shu, Shuangshuang; Xiang, Xiaohong; Guo, Tingting; Yang, Lei; Zhang, Shaojie; Tang, Xun; Zhang, Jun

    2016-01-01

    Endothelial-to-mesenchymal transition (EndMT) in renal glomerular endothelial cells plays a critical role in the pathogenesis of diabetic nephropathy (DN). Furthermore, advanced oxidation protein products (AOPPs) have been shown to contribute to the progression of DN. However, whether AOPPs induce EndMT in renal glomerular endothelial cells remains unclear. Thus, we investigated the effect of AOPPs on human renal glomerular endothelial cells (HRGECs) and the mechanisms underlying the effects. Our results showed that AOPP treatment lowered the expression of vascular endothelial cadherin, CD31, and claudin 5 and induced the overexpression of α-smooth muscle actin, vimentin, and fibroblast-specific protein 1, which indicated that AOPPs induced EndMT in HRGECs. Furthermore, AOPP stimulation increased the expression of glucose-regulated protein 78 and CCAAT/enhancer-binding protein-homologous protein, which suggested that AOPPs triggered endoplasmic reticulum (ER) stress in HRGECs. Notably, the aforementioned AOPP effects were reversed following the treatment of cells with salubrinal, an inhibitor of ER stress, whereas the effects were reproduced after exposure to thapsigargin, an inducer of ER stress. Collectively, our results indicate that AOPPs trigger EndMT in HRGECs through the induction of ER stress. These findings suggest novel therapeutic strategies for inhibiting renal fibrosis by targeting ER stress. PMID:26861949

  20. An Increase of Plasma Advanced Oxidation Protein Products Levels Is Associated with Cardiovascular Risk in Incident Peritoneal Dialysis Patients: A Pilot Study

    PubMed Central

    Gonzalez, Elena; Bajo, Maria-Auxiliadora; Carrero, Juan J.; Lindholm, Bengt; Grande, Cristina; Sánchez-Villanueva, Rafael; Del Peso, Gloria; Díaz-Almirón, Mariana; Iglesias, Pedro; Díez, Juan J.; Selgas, Rafael

    2015-01-01

    Advanced oxidation protein products (AOPPs) are considered as markers and even mediators of the proinflammatory effect of oxidative stress in uremia. We hypothesized that an increase of oxidative stress associated with peritoneal dialysis (PD), estimated by the variation of plasma AOPPs over time, might be associated with cardiovascular (CV) risk and overall prognosis. In 48 PD patients, blood samples were collected on two occasions: the first one in the first six months after starting PD therapy and the second one, one year after. The plasma AOPPs level variation over the first year on PD was significantly associated with CV antecedents and also with CV prognosis. In those patients in whom the AOPPs levels increased more than 50% above the baseline value, a significant association with past and future CV disease was confirmed. These patients had 4.7 times greater risk of suffering later CV disease than those with a smaller increase, even after adjusting for previous CV history. Our data suggest that the increase of AOPPs plasma level over the first year on PD is conditioned by CV antecedents but also independently predicts CV prognosis. AOPPs plasma levels seem to represent the CV status of PD patients with sufficient sensitivity to identify those with a clearly sustained higher CV risk. PMID:26581178

  1. Advanced protein formulations

    PubMed Central

    Wang, Wei

    2015-01-01

    It is well recognized that protein product development is far more challenging than that for small-molecule drugs. The major challenges include inherent sensitivity to different types of stresses during the drug product manufacturing process, high rate of physical and chemical degradation during long-term storage, and enhanced aggregation and/or viscosity at high protein concentrations. In the past decade, many novel formulation concepts and technologies have been or are being developed to address these product development challenges for proteins. These concepts and technologies include use of uncommon/combination of formulation stabilizers, conjugation or fusion with potential stabilizers, site-specific mutagenesis, and preparation of nontraditional types of dosage forms—semiaqueous solutions, nonfreeze-dried solid formulations, suspensions, and other emerging concepts. No one technology appears to be mature, ideal, and/or adequate to address all the challenges. These gaps will likely remain in the foreseeable future and need significant efforts for ultimate resolution. PMID:25858529

  2. Glucagon-like peptide-1 protects cardiomyocytes from advanced oxidation protein product-induced apoptosis via the PI3K/Akt/Bad signaling pathway

    PubMed Central

    ZHANG, HUA; XIONG, ZHOUYI; WANG, JIAO; ZHANG, SHUANGSHUANG; LEI, LEI; YANG, LI; ZHANG, ZHEN

    2016-01-01

    Cardiomyocyte apoptosis is a major event in the pathogenesis of diabetic cardiomyopathy. Currently, no single effective treatment for diabetic cardiomyopathy exists. The present study investigated whether advanced oxidative protein products (AOPPs) have a detrimental role in the survival of cardiomyocytes and if glucagon-like peptide-1 (GLP-1) exerts a cardioprotective effect under these circumstances. The present study also aimed to determine the underlying mechanisms. H9c2 cells were exposed to increasing concentrations of AOPPs in the presence or absence of GLP-1, and the viability and apoptotic rate were detected using a cell counting kit-8 assay and flow cytometry, respectively. In addition, a phosphatidylino-sitol-4,5-bisphosphate 3-kinase (PI3K) inhibitor, LY294002, was employed to illustrate the mechanism of the antiapoptotic effect of GLP-1. The expression levels of the apoptotic-associated proteins, Akt, B-cell lymphoma (Bcl)-2, Bcl-2-associated death promoter (Bad), Bcl-2-associated X protein (Bax) and caspase-3 were measured by western blotting. It was revealed that GLP-1 significantly attenuated AOPP-induced cell toxicity and apoptosis. AOPPs inactivated the phosphorylation of Akt, reduced the phosphorylation of Bad, decreased the expression of Bcl-2, increased the expression of Bax and the activation of caspase-3 in H9c2 cells. GLP-1 reversed the above changes induced by AOPPs and the protective effects of GLP-1 were abolished by the PI3K inhibitor, LY294002. In conclusion, the present data suggested that GLP-1 protected cardiomyocytes against AOPP-induced apoptosis, predominantly via the PI3K/Akt/Bad pathway. These results provided a conceivable mechanism for the development of diabetic cardiomyopathy and rendered a novel application of GLP-1 exerting favorable cardiac effects for the treatment of diabetic cardiomyopathy. PMID:26717963

  3. Lipid advanced glycosylation: pathway for lipid oxidation in vivo.

    PubMed Central

    Bucala, R; Makita, Z; Koschinsky, T; Cerami, A; Vlassara, H

    1993-01-01

    To address potential mechanisms for oxidative modification of lipids in vivo, we investigated the possibility that phospholipids react directly with glucose to form advanced glycosylation end products (AGEs) that then initiate lipid oxidation. Phospholipid-linked AGEs formed readily in vitro, mimicking the absorbance, fluorescence, and immunochemical properties of AGEs that result from advanced glycosylation of proteins. Oxidation of unsaturated fatty acid residues, as assessed by reactive aldehyde formation, occurred at a rate that paralleled the rate of lipid advanced glycosylation. Aminoguanidine, an agent that prevents protein advanced glycosylation, inhibited both lipid advanced glycosylation and oxidative modification. Incubation of low density lipoprotein (LDL) with glucose produced AGE moieties that were attached to both the lipid and the apoprotein components. Oxidized LDL formed concomitantly with AGE-modified LDL. Of significance, AGE ELISA analysis of LDL specimens isolated from diabetic individuals revealed increased levels of both apoprotein- and lipid-linked AGEs when compared to specimens obtained from normal, nondiabetic controls. Circulating levels of oxidized LDL were elevated in diabetic patients and correlated significantly with lipid AGE levels. These data support the concept that AGE oxidation plays an important and perhaps primary role in initiating lipid oxidation in vivo. PMID:8341651

  4. Advanced Protein Crystallization Facility (APCF)

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This section of the Life and Microgravity Spacelab (LMS) publication contains articles entitled: (1) Crystallization of EGFR-EGF; (2) Crystallization of Apocrustacyanin C1; (3) Crystallization and X-ray Analysis of 5S rRNA and the 5S rRNA Domain A; (4) Growth of Lysozyme Crystals at Low Nucleation Density; (5) Comparative Analysis of Aspartyl tRNA-synthetase and Thaumatin Crystals Grown on Earth and In Microgravity; (6) Lysosome Crystal Growth in the Advanced Protein Crystallization Facility Monitored via Mach-Zehnder Interferometry and CCD Video; (7) Analysis of Thaumatin Crystals Grown on Earth and in Microgravity; (8) Crystallization of the Nucleosome Core Particle; (9) Crystallization of Photosystem I; (10) Mechanism of Membrane Protein Crystal Growth: Bacteriorhodopsin-mixed Micelle Packing at the Consolution Boundary, Stabilized in Microgravity; (11) Crystallization in a Microgravity Environment of CcdB, a Protein Involved in the Control of Cell Death; and (12) Crystallization of Sulfolobus Solfataricus

  5. [Carbonyl stress and oxidatively modified proteins in chronic renal failure].

    PubMed

    Bargnoux, A-S; Morena, M; Badiou, S; Dupuy, A-M; Canaud, B; Cristol, J-P

    2009-01-01

    Oxidative stress is commonly observed in chronic renal failure patients resulting from an unbalance between overproduction of reactive oxygen species and impairement of defense mechanisms. Proteins appear as potential targets of uremia-induced oxidative stress and may undergo qualitative modifications. Proteins could be directly modified by reactive oxygen species which leads to amino acid oxydation and cross-linking. Proteins could be indirectly modified by reactive carbonyl compounds produced by glycoxidation and lipo-peroxidation. The resulting post-traductional modifications are known as carbonyl stress. In addition, thiols could be oxidized or could react with homocystein leading to homocysteinylation. Finally, tyrosin could be oxidized by myeloperoxidase leading to advanced oxidative protein products (AOPP). Oxidatively modified proteins are increased in chronic renal failure patients and may contribute to exacerbate the oxidative stress/inflammation syndrome. They have been involved in long term complications of uremia such as amyloidosis and accelerated atherosclerosis. PMID:19297289

  6. Oxidation of advanced steam turbine alloys

    SciTech Connect

    Holcomb, G.R.; Covino, B.S., Jr.; Bullard, S.J.; Ziomek-Moroz, M.

    2006-03-01

    Advanced or ultra supercritical (USC) steam power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include coal generation at 60% efficiency, which would require steam temperatures of up to 760°C. This research examines the steamside oxidation of advanced alloys for use in USC systems, with emphasis placed on alloys for high- and intermediate-pressure turbine sections.

  7. Oxidation of alloys for advanced steam turbines

    SciTech Connect

    Holcomb, Gordon R.; Covino, Bernard S., Jr.; Bullard, Sophie J.; Ziomek-Moroz, M.; Alman, David E.

    2005-01-01

    Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include coal generation at 60% efficiency, which would require steam temperatures of up to 760°C. This research examines the steamside oxidation of advanced alloys for use in USC systems, with emphasis placed on alloys for high- and intermediate-pressure turbine sections.

  8. HANDBOOK ON ADVANCED NONPHOTOCHEMICAL OXIDATION PROCESSES

    EPA Science Inventory

    The purpose of this handbook is to summarize commercial-scale system performance and cost data for advanced nonphotochemical oxidation (ANPO) treatment of contaminated water, air, and soil. Similar information from pilot-and bench-scale evaluations of ANPO processes is also inclu...

  9. HANDBOOK ON ADVANCED PHOTOCHEMICAL OXIDATION PROCESSES

    EPA Science Inventory

    This handbook summarizes commercial-scale system performance and cost data for advanced photochemical oxidation (APO) treatment of contaminated water, air, and solids. Similar information from pilot- and bench-scale evaluations of APO processes is also included to supplement the...

  10. Advances in the directed evolution of proteins

    PubMed Central

    Lane, Michael D.; Seelig, Burckhard

    2014-01-01

    Natural evolution has produced a great diversity of proteins that can be harnessed for numerous applications in biotechnology and pharmaceutical science. Commonly, specific applications require proteins to be tailored by protein engineering. Directed evolution is a type of protein engineering that yields proteins with the desired properties under well-defined conditions and in a practical time frame. While directed evolution has been employed for decades, recent creative developments enable the generation of proteins with previously inaccessible properties. Novel selection strategies, faster techniques, the inclusion of unnatural amino acids or modifications, and the symbiosis of rational design approaches and directed evolution continue to advance protein engineering. PMID:25309990

  11. Advanced protein crystal growth programmatic sensitivity study

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The purpose of this study is to define the costs of various APCG (Advanced Protein Crystal Growth) program options and to determine the parameters which, if changed, impact the costs and goals of the programs and to what extent. This was accomplished by developing and evaluating several alternate programmatic scenarios for the microgravity Advanced Protein Crystal Growth program transitioning from the present shuttle activity to the man tended Space Station to the permanently manned Space Station. These scenarios include selected variations in such sensitivity parameters as development and operational costs, schedules, technology issues, and crystal growth methods. This final report provides information that will aid in planning the Advanced Protein Crystal Growth Program.

  12. Oxidation of Alloys for Advanced Steam Turbines

    SciTech Connect

    Holcomb, G.R.; Ziomek-Moroz, M.E.; Alman, D.E.

    2006-09-01

    Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include power generation from coal at 60% efficiency, which requires steam temperatures of up to 760°C. This research examines the steam oxidation of alloys for use in USC systems, with emphasis placed on applications in high- and intermediate-pressure turbines.

  13. Advanced oxidation process sanitization of eggshell surfaces.

    PubMed

    Gottselig, Steven M; Dunn-Horrocks, Sadie L; Woodring, Kristy S; Coufal, Craig D; Duong, Tri

    2016-06-01

    The microbial quality of eggs entering the hatchery represents an important critical control point for biosecurity and pathogen reduction programs in integrated poultry production. The development of safe and effective interventions to reduce microbial contamination on the surface of eggs will be important to improve the overall productivity and microbial food safety of poultry and poultry products. The hydrogen peroxide (H2O2) and ultraviolet (UV) light advanced oxidation process is a potentially important alternative to traditional sanitizers and disinfectants for egg sanitation. The H2O2/UV advanced oxidation process was demonstrated previously to be effective in reducing surface microbial contamination on eggs. In this study, we evaluated treatment conditions affecting the efficacy of H2O2/UV advanced oxidation in order to identify operational parameters for the practical application of this technology in egg sanitation. The effect of the number of application cycles, UV intensity, duration of UV exposure, and egg rotation on the recovery of total aerobic bacteria from the surface of eggs was evaluated. Of the conditions evaluated, we determined that reduction of total aerobic bacteria from naturally contaminated eggs was optimized when eggs were sanitized using 2 repeated application cycles with 5 s exposure to 14 mW cm(-2) UV light, and that rotation of the eggs between application cycles was unnecessary. Additionally, using these optimized conditions, the H2O2/UV process reduced Salmonella by greater than 5 log10 cfu egg(-1) on the surface of experimentally contaminated eggs. This study demonstrates the potential for practical application of the H2O2/UV advanced oxidation process in egg sanitation and its effectiveness in reducing Salmonella on eggshell surfaces. PMID:27030693

  14. Characterization of advanced oxidation regenerated GACs

    SciTech Connect

    Singh, J.; Cannon, F.S.

    1995-11-01

    Industrial and manufacturing processes that employ organic solvents, such as pharmaceutical production, spray booth coating applications, and petrochemical processing, constitute a major source of airborne volatile organic contaminants (VOCs) and hazardous air pollutants (HAPs). VOCs released into the atmosphere react with sunlight to create photochemical smog, oxidants and other pollutants, all of which are considered harmful to animal and plant life. There is thus a need for effective air pollution remediation technologies for such facilities. This paper explores the effects of regeneration by means of advanced oxidation involving UV and ozone, on several properties of granular activated carbons (GACs). The effects of reduction in surface areas and pore volumes, and surface oxidation due to this process of regeneration, on adsorption capacities of some model VOCs is investigated.

  15. Novel imazethapyr detoxification applying advanced oxidation processes.

    PubMed

    Stathis, Ioannis; Hela, Dimitra G; Scrano, Laura; Lelario, Filomena; Emanuele, Lucia; Bufo, Sabino A

    2011-01-01

    Different degradation methods have been applied to assess the suitability of advanced oxidation process (AOPs) to promote mineralization of imazethapyr [(RS)-5-ethyl-2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid], a widely used imidazolinone class herbicide, the persistence of which has been demonstrated in surface and ground waters destined to human uses. Independent of the oxidation process assessed, the decomposition of imazethapyr always followed a pseudo-first order kinetic. The direct UV-irradiation (UV) of the herbicide as well as its oxidation with ozone (O₃), and hydrogen peroxide tied to UV-irradiation (H₂O₂/UV) were sufficiently slow to permit the identification of intermediate products, the formation pathway of which has been proposed. Ozonation joined to UV-irradiation (O₃/UV), ozonation joined to titanium dioxide photo-catalysis (TiO₂/UV+O₃), sole photo-catalysis (TiO₂/UV), and photo-catalysis reinforced with hydrogen peroxide-oxidation (TiO₂/UV+H₂O₂) were characterized by a faster degradation and rapid formation of a lot of small molecules, which were quickly degraded to complete mineralization. The most effective oxidation methods were those using titanium dioxide photo-catalysis enhanced either by ozonation or hydrogen peroxide. Most of all, these last processes were useful to avoid the development of dangerous by-products. PMID:21726140

  16. Induced effects of advanced oxidation processes

    NASA Astrophysics Data System (ADS)

    Liu, Peng; Li, Chaolin; Zhao, Zhuanjun; Lu, Gang; Cui, Haibo; Zhang, Wenfang

    2014-02-01

    Hazardous organic wastes from industrial, military, and commercial activities represent one of the greatest challenges to human beings. Advanced oxidation processes (AOPs) are alternatives to the degradation of those organic wastes. However, the knowledge about the exact mechanisms of AOPs is still incomplete. Here we report a phenomenon in the AOPs: induced effects, which is a common property of combustion reaction. Through analysis EDTA oxidation processes by Fenton and UV-Fenton system, the results indicate that, just like combustion, AOPs are typical induction reactions. One most compelling example is that pre-feeding easily oxidizable organic matter can promote the oxidation of refractory organic compound when it was treated by AOPs. Connecting AOPs to combustion, it is possible to achieve some helpful enlightenment from combustion to analyze, predict and understand AOPs. In addition, we assume that maybe other oxidation reactions also have induced effects, such as corrosion, aging and passivation. Muchmore research is necessary to reveal the possibilities of induced effects in those fields.

  17. Induced effects of advanced oxidation processes

    PubMed Central

    Liu, Peng; Li, Chaolin; Zhao, Zhuanjun; Lu, Gang; Cui, Haibo; Zhang, Wenfang

    2014-01-01

    Hazardous organic wastes from industrial, military, and commercial activities represent one of the greatest challenges to human beings. Advanced oxidation processes (AOPs) are alternatives to the degradation of those organic wastes. However, the knowledge about the exact mechanisms of AOPs is still incomplete. Here we report a phenomenon in the AOPs: induced effects, which is a common property of combustion reaction. Through analysis EDTA oxidation processes by Fenton and UV-Fenton system, the results indicate that, just like combustion, AOPs are typical induction reactions. One most compelling example is that pre-feeding easily oxidizable organic matter can promote the oxidation of refractory organic compound when it was treated by AOPs. Connecting AOPs to combustion, it is possible to achieve some helpful enlightenment from combustion to analyze, predict and understand AOPs. In addition, we assume that maybe other oxidation reactions also have induced effects, such as corrosion, aging and passivation. Muchmore research is necessary to reveal the possibilities of induced effects in those fields. PMID:24503715

  18. Acute reduction of serum 8-iso-PGF2-alpha and advanced oxidation protein products in vivo by a polyphenol-rich beverage; a pilot clinical study with phytochemical and in vitro antioxidant characterization

    PubMed Central

    2011-01-01

    Background Measuring the effects of the acute intake of natural products on human biomarker concentrations, such as those related to oxidation and inflammation, can be an advantageous strategy for early clinical research on an ingredient or product. Methods 31 total healthy subjects were randomized in a double-blinded, placebo-controlled, acute pilot study with post-hoc subgroup analysis on 20 of the subjects. The study examined the effects of a single dose of a polyphenol-rich beverage (PRB), commercially marketed as "SoZo®", on serum anti-inflammatory and antioxidant markers. In addition, phytochemical analyses of PRB, and in vitro antioxidant capacity were also performed. Results At 1 hour post-intake, serum values for 8-iso-PGF2-alpha and advanced oxidation protein products decreased significantly by 40% and 39%, respectively. Additionally, there was a trend toward decreased C-reactive protein, and increased nitric oxide levels. Both placebo and PRB treatment resulted in statistically significant increases in hydroxyl radical antioxidant capacity (HORAC) compared to baseline; PRB showed a higher percent change (55-75% versus 23-74% in placebo group), but the two groups did not differ significantly from each other. Conclusions PRB produced statistically significant changes in several blood biomarkers related to antioxidant/anti-inflammatory effects. Future studies are justified to verify results and test for cumulative effects of repeated intakes of PRB. The study demonstrates the potential utility of acute biomarker measurements for evaluating antioxidant/anti-inflammatory effects of natural products. PMID:21676230

  19. Recent advances in mammalian protein production

    PubMed Central

    Bandaranayake, Ashok D.; Almo, Steven C.

    2014-01-01

    Mammalian protein production platforms have had a profound impact in many areas of basic and applied research, and an increasing number of blockbuster drugs are recombinant mammalian proteins. With global sales of these drugs exceeding US$120 billion per year, both industry and academic research groups continue to develop cost effective methods for producing mammalian proteins to support preclinical and clinical evaluations of potential therapeutics. While a wide range of platforms have been successfully exploited for laboratory use, the bulk of recent biologics have been produced in mammalian cell lines due to the requirement for post translational modification and the biosynthetic complexity of the target proteins. In this review we highlight the range of mammalian expression platforms available for recombinant protein production, as well as advances in technologies for the rapid and efficient selection of highly productive clones. PMID:24316512

  20. A novel approach in psoriasis: first usage of known protein oxidation markers to prove oxidative stress.

    PubMed

    Yazici, Cevat; Köse, Kader; Utaş, Serap; Tanrikulu, Esen; Taşlidere, Nazan

    2016-04-01

    Oxidative stress may play a pivotal role in the pathogenesis of psoriasis, an inflammatory/hyperproliferative skin disease characterized by the cutaneous accumulation of neutrophils releasing reactive oxygen species, as revealed in a number of studies. This study was performed to demonstrate the presence of oxidative stress in psoriasis, as measured by protein oxidation markers. Twenty-nine psoriasis patients were selected based on disease severity assessment using body surface area as well as the psoriasis area severity index (PASI), and were grouped as mild (PASI ≤ 10) and moderate-to-severe (PASI > 10). The measured parameters in psoriatic patients and fourteen healthy volunteers were as follows: erythrocyte sedimentation rate (ESR), high sensitive C-reactive protein (CRP), myeloperoxidase (MPO) activity, neopterin, total lipid hydroperoxides (LHP), pyrrolized protein (PP), protein carbonyl compounds (PCC), advanced oxidation protein products (AOPP), thiol levels, along with complete blood count. Except lower thiols, all parameters were found to be higher in total patients as well as in subgroups, compared to controls. There was no significant difference among the subgroups. In conclusion, protein oxidation in psoriatics, not only in moderate-to-severe, but also in mild patients, may be explained by the findings of inflammation, phagocytic cell oxidation, and MPO-hypochlorous acid-oxidation reactions; as reflected by increased total/differential leucocytes counts, CRP, ESR as well as MPO, neopterin, AOPP, PCC, PP, LHP, and decreased thiol levels. Demonstrating the AOPP and PP formation for the first time, oxidants from active neutrophils/monocytes may play an important role in the pathogenesis of psoriasis, leading to oxidative stress, especially by protein oxidation. PMID:26842230

  1. The oxidative environment and protein damage.

    PubMed

    Davies, Michael J

    2005-01-17

    Proteins are a major target for oxidants as a result of their abundance in biological systems, and their high rate constants for reaction. Kinetic data for a number of radicals and non-radical oxidants (e.g. singlet oxygen and hypochlorous acid) are consistent with proteins consuming the majority of these species generated within cells. Oxidation can occur at both the protein backbone and on the amino acid side-chains, with the ratio of attack dependent on a number of factors. With some oxidants, damage is limited and specific to certain residues, whereas other species, such as the hydroxyl radical, give rise to widespread, relatively non-specific damage. Some of the major oxidation pathways, and products formed, are reviewed. The latter include reactive species, such as peroxides, which can induce further oxidation and chain reactions (within proteins, and via damage transfer to other molecules) and stable products. Particular emphasis is given to the oxidation of methionine residues, as this species is readily oxidised by a wide range of oxidants. Some side-chain oxidation products, including methionine sulfoxide, can be employed as sensitive, specific, markers of oxidative damage. The product profile can, in some cases, provide valuable information on the species involved; selected examples of this approach are discussed. Most protein damage is non-repairable, and has deleterious consequences on protein structure and function; methionine sulfoxide formation can however be reversed in some circumstances. The major fate of oxidised proteins is catabolism by proteosomal and lysosomal pathways, but some materials appear to be poorly degraded and accumulate within cells. The accumulation of such damaged material may contribute to a range of human pathologies. PMID:15680218

  2. ADVANCED OXIDATION TECHNOLOGIES FOR THE TREATMENT OF CONTAMINATED GROUNDWATER

    EPA Science Inventory

    This paper presents information on two pilot-field appliations of advanced oxidation technologies for contaminated groundwater with organis. The two UV/oxidation technologies were developed by Ultrox International of Santa Ana, California and Peroxidatrion Systems, Inc. of Tucso...

  3. Short communication: Effect of commercial or depurinized milk diet on plasma advanced oxidation protein products, cardiovascular markers, and bone marrow CD34+ stem cell potential in rat experimental hyperuricemia.

    PubMed

    Kocic, Gordana; Sokolovic, Dusan; Jevtovic, Tatjana; Cvetkovic, Tatjana; Veljkovic, Andrej; Kocic, Hristina; Stojanovic, Svetlana; Jovanovic, Aneta; Jovanovic, Jelena; Zivkovic, Petar

    2014-11-01

    Cardiovascular repair and myocardial contractility may be improved by migration of bone marrow stem cells (BMSC) and their delivery to the site of injury, a process known as BMSC homing. The aim of our study was to examine the dietary effect of a newly patented depurinized milk (DP) that is almost free of uric acid and purine and pyrimidine compounds compared with a standard commercial 1.5% fat UHT milk diet or allopurinol therapy in rat experimental hyperuricemia. Bone marrow stem cell potential (BMCD34(+), CD34-postive bone marrow cells), plasma oxidative stress parameters [advanced oxidation protein products, AOPP) and thiobarbituric acid reactive substances (TBARS)], myocardial damage markers [creatine phosphokinase (CPK), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH)], plasma cholesterol, and high-density lipoprotein cholesterol were investigated. The DP milk diet significantly increased the number of BMCD34(+) stem cells compared with commercial UHT milk. Allopurinol given alone also increased the number of BMCD34(+). Hyperuricemia caused a significant increase in all plasma enzyme markers for myocardial damage (CPK, LDH, and AST). A cardioprotective effect was achieved with allopurinol but almost equally with DP milk and more than with commercial milk. Regarding plasma AOPP, TBARS, and cholesterol levels, the most effective treatment was DP milk. In conclusion, the protective role of a milk diet on cardiovascular function may be enhanced through the new depurinized milk diet, which may improve cardiovascular system function via increased bone marrow stem cell regenerative potential, decreased plasma oxidative stress parameters, and decreased levels of myocardial damage markers and cholesterol. New dairy technology strategies focused on eliminating harmful milk compounds should be completely nontoxic. Novel milk products should be tested for their ability to improve tissue repair and function. PMID:25218755

  4. Tryptophan oxidation in proteins exposed to thiocyanate-derived oxidants.

    PubMed

    Bonifay, Vincent; Barrett, Tessa J; Pattison, David I; Davies, Michael J; Hawkins, Clare L; Ashby, Michael T

    2014-12-15

    Human defensive peroxidases, including lactoperoxidase (LPO) and myeloperoxidase (MPO), are capable of catalyzing the oxidation of halides (X(-)) by H2O2 to give hypohalous acids (HOX) for the purpose of cellular defense. Substrate selectivity depends upon the relative abundance of the halides, but the pseudo-halide thiocyanate (SCN(-)) is a major substrate, and sometimes the exclusive substrate, of all defensive peroxidases in most physiologic fluids. The resulting hypothiocyanous acid (HOSCN) has been implicated in cellular damage via thiol oxidation. While thiols are believed to be the primary target of HOSCN in vivo, Trp residues have also been implicated as targets for HOSCN. However, the mechanism involved in HOSCN-mediated Trp oxidation was not established. Trp residues in proteins appeared to be susceptible to oxidation by HOSCN, whereas free Trp and Trp residues in small peptides were found to be unreactive. We show that HOSCN-induced Trp oxidation is dependent on pH, with oxidation of free Trp, and Trp-containing peptides observed when the pH is below 2. These conditions mimic those employed previously to precipitate proteins after treatment with HOSCN, which accounts for the discrepancy in the results reported for proteins versus free Trp and small peptides. The reactant in these cases may be thiocyanogen ((SCN)2), which is produced by comproportionation of HOSCN and SCN(-) at low pH. Reaction of thiocyanate-derived oxidants with protein Trp residues at low pH results in the formation of a number of oxidation products, including mono- and di-oxygenated derivatives, which are also formed with other hypohalous acids. Our data suggest that significant modification of Trp by HOSCN in vivo is likely to have limited biological relevance. PMID:25172223

  5. Advanced oxidation technologies for chemical demilitarization

    SciTech Connect

    Rosocha, L.A.; Korzekwa, R.A.; Monagle, M.; Coogan, J.J.; Tennant, R.A.; Brown, L.F.; Currier, R.P.

    1996-12-31

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory. The main project objective was to establish a technical basis for future program development in the area of chemical warfare agent destruction using a Los Alamos-developed advanced oxidation process: a two-stage device consisting of thermal packed-bed reactor (PBR) and a nonthermal plasma (NTP) reactor. Various compounds were evaluated as potential surrogates for chemical warfare (CW) agents. Representative effluent mass balances were projected for future comparisons with incinerators. The design and construction of lab-scale PBR/NTP reactors (consisting of a liquid injection and metering system, electric furnace, condensers, chemical traps, plasma reactors, power supplies, and chemical diagnostics) has been completed. This equipment, the experience gained from chemical-processing experiments, process modeling, and an initial demonstration of the feasibility of closed-loop operation, have provided a technical basis for further demonstrations and program development efforts.

  6. Average oxidation state of carbon in proteins

    PubMed Central

    Dick, Jeffrey M.

    2014-01-01

    The formal oxidation state of carbon atoms in organic molecules depends on the covalent structure. In proteins, the average oxidation state of carbon (ZC) can be calculated as an elemental ratio from the chemical formula. To investigate oxidation–reduction (redox) patterns, groups of proteins from different subcellular locations and phylogenetic groups were selected for comparison. Extracellular proteins of yeast have a relatively high oxidation state of carbon, corresponding with oxidizing conditions outside of the cell. However, an inverse relationship between ZC and redox potential occurs between the endoplasmic reticulum and cytoplasm. This trend provides support for the hypothesis that protein transport and turnover are ultimately coupled to the maintenance of different glutathione redox potentials in subcellular compartments. There are broad changes in ZC in whole-genome protein compositions in microbes from different environments, and in Rubisco homologues, lower ZC tends to occur in organisms with higher optimal growth temperature. Energetic costs calculated from thermodynamic models are consistent with the notion that thermophilic organisms exhibit molecular adaptation to not only high temperature but also the reducing nature of many hydrothermal fluids. Further characterization of the material requirements of protein metabolism in terms of the chemical conditions of cells and environments may help to reveal other linkages among biochemical processes with implications for changes on evolutionary time scales. PMID:25165594

  7. Protein oxidation, UVA and human DNA repair.

    PubMed

    Karran, Peter; Brem, Reto

    2016-08-01

    Solar UVB is carcinogenic. Nucleotide excision repair (NER) counteracts the carcinogenicity of UVB by excising potentially mutagenic UVB-induced DNA lesions. Despite this capacity for DNA repair, non-melanoma skin cancers and apparently normal sun-exposed skin contain huge numbers of mutations that are mostly attributable to unrepaired UVB-induced DNA lesions. UVA is about 20-times more abundant than UVB in incident sunlight. It does cause some DNA damage but this does not fully account for its biological impact. The effects of solar UVA are mediated by its interactions with cellular photosensitizers that generate reactive oxygen species (ROS) and induce oxidative stress. The proteome is a significant target for damage by UVA-induced ROS. In cultured human cells, UVA-induced oxidation of DNA repair proteins inhibits DNA repair. This article addresses the possible role of oxidative stress and protein oxidation in determining DNA repair efficiency - with particular reference to NER and skin cancer risk. PMID:27324272

  8. Pathways of Transport Protein Evolution: Recent Advances

    PubMed Central

    Lam, Vincent H.; Lee, Jong-Hoon; Silverio, Abe; Chan, Henry; Gomolplitinant, Kenny M.; Povolotsky, Tatyana L.; Orlova, Ekaterina; Sun, Eric I.; Welliver, Carl H.; Saier, Milton H.

    2014-01-01

    We herein report recent advances in our understanding of transport protein evolution. The Drug-Metabolite Transporter (DMT) superfamily (TC# 2.A.7) arose from a 2TMS precursor to give 4TMS proteins which then added one and duplicated to give 10. The proposed pathway is 2 –> 4 –> 5 –> 10. This superfamily provides a rare example where all proposed topological intermediates in this evolutionary pathway have been identified in current protein databases. Another family, the Oligopeptide Transporter (OPT) family (TC# 2.A.67), also started with a 2 TMS peptide precursor, but it followed the pathway: Only 16 and 17 TMS OPT family members have been identified in current databases. The TRIC family of K+ channels, characterized in animals, arose via the pathway: where the seventh TMS was added c-terminally to the 6 TMS precursor that resulted from a 3 TMS duplication. Surprisingly, animal TRIC channels proved to have numerous 7 TMS homologues in prokaryotes, none of which had been identified previously. We found that two families of integral membrane proteins gave rise to multiple current topological types. Members of the SdpC killer factor immunity protein family, SdpI (TC# 9.A.32) probably arose via the pathway: while members of the Heme Handling Protein (HHP) Family (TC# 9.B.14) arose via the pathway: Predictions are also made for an evolutionary pathway giving rise to the seven topological types of P-type ATPases so far identified in the P-ATPase superfamily. Finally, the ubiquitous CDF carriers (TC# 1.A.4) of 6TMSs probably gave rise to CRAC channels of 4TMSs by loss of the first two TMSs an unusual example of retroevolution. PMID:21194372

  9. Importance of glycolysis and oxidative phosphorylation in advanced melanoma

    PubMed Central

    2012-01-01

    Serum lactate dehydrogenase (LDH) is a prognostic factor for patients with stage IV melanoma. To gain insights into the biology underlying this prognostic factor, we analyzed total serum LDH, serum LDH isoenzymes, and serum lactate in up to 49 patients with metastatic melanoma. Our data demonstrate that high serum LDH is associated with a significant increase in LDH isoenzymes 3 and 4, and a decrease in LDH isoenzymes 1 and 2. Since LDH isoenzymes play a role in both glycolysis and oxidative phosphorylation (OXPHOS), we subsequently determined using tissue microarray (TMA) analysis that the levels of proteins associated with mitochondrial function, lactate metabolism, and regulators of glycolysis were all elevated in advanced melanomas compared with nevic melanocytes. To investigate whether in advanced melanoma, the glycolysis and OXPHOS pathways might be linked, we determined expression of the monocarboxylate transporters (MCT) 1 and 4. Analysis of a nevus-to-melanoma progression TMA revealed that MCT4, and to a lesser extend MCT1, were elevated with progression to advanced melanoma. Further analysis of human melanoma specimens using the Seahorse XF24 extracellular flux analyzer indicated that metastatic melanoma tumors derived a large fraction of energy from OXPHOS. Taken together, these findings suggest that in stage IV melanomas with normal serum LDH, glycolysis and OXPHOS may provide metabolic symbiosis within the same tumor, whereas in stage IV melanomas with high serum LDH glycolysis is the principle source of energy. PMID:23043612

  10. Protein oxidation in hemodialysis and kidney transplantation.

    PubMed

    Odetti, P; Garibaldi, S; Gurreri, G; Aragno, I; Dapino, D; Pronzato, M A; Marinari, U M

    1996-11-01

    Oxidative damage of plasma proteins determined with the markers carbonyl group (CG) content and thiobarbituric acid-reactive substances (TBARS) was studied in 13 hemodialyzed and eight kidney-transplanted patients. The level of CGs was 38% higher in hemodialysis (HD) patients (1.49 +/- 0.05 nmol/mg protein) than in the healthy subjects (1.08 +/- 0.03 nmol/mg protein); the TBARS level was also higher in HD patients than in the control group (2.64 +/- 0.15 v 1.81 +/- 0.09 nmol/mL, P < .001). These data confirm that in end-stage renal failure, an increased oxidative stress is present and is able to induce protein damage. After transplantation, the CG content in protein was reduced (1.34 +/- 0.08 nmol/mg protein), but it was not significantly different from the level in the HD group. The failure to return to the normal range suggests that an impaired redox status is maintained, resulting in a sustained elevation of CG. Conversely, the level of TBARS in transplanted patients (1.99 +/- 0.22 nmol/mL) was not significantly different from that in the control group (1.81 +/- 0.09), suggesting that lipoperoxidation may be inhibited. These results may be explained by the different turnover rates of the molecules and by the distinct origin of the two markers, resulting from the damage of proteins or lipids. Thus, lipoperoxidation would produce rapidly removable molecules, whereas protein oxidation damage would tend to accumulate. However, the significant correlation found between CGs and TBARS indicates that a common cause (oxidative stress) binds the two markers of damage. PMID:8931632

  11. Oxidative damage to human plasma proteins by ozone.

    PubMed

    Cross, C E; Reznick, A Z; Packer, L; Davis, P A; Suzuki, Y J; Halliwell, B

    1992-01-01

    Exposure of human plasma to ozone produces oxidative protein damage, measured as protein carbonyl formation. Isolated human albumin or creatine phosphokinase are oxidized much faster than are total proteins. Consideration must be given to proteins as targets of oxidative injury by ozone in vivo. PMID:1568641

  12. ADVANCED OXIDATION PROCESSES (AOP'S FOR THE TREATMENT OF CCL CHEMICALS

    EPA Science Inventory

    Research on treatment of Contaminant Candidate List (CCL) chemicals is being conducted. Specific groups of contaminants on the CCL will be evaluated using numerous advanced oxidation processes (AOPs). Initially, these CCL contaminants will be evaluated in groups based on chemical...

  13. SULFATE RADICAL-BASED ADVANCED OXIDATION PROCESSES- ACS MEETING

    EPA Science Inventory

    This paper will present an overview of sulfate radical-based advanced oxidation technologies for the destruction of environmentally toxic chemicals in wastewater, industrial water, groundwater and sources of water supply. The paper will include fundamental aspects of the generati...

  14. Oxidation-Reduction Resistance of Advanced Copper Alloys

    NASA Technical Reports Server (NTRS)

    Greenbauer-Seng, L. (Technical Monitor); Thomas-Ogbuji, L.; Humphrey, D. L.; Setlock, J. A.

    2003-01-01

    Resistance to oxidation and blanching is a key issue for advanced copper alloys under development for NASA's next generation of reusable launch vehicles. Candidate alloys, including dispersion-strengthened Cu-Cr-Nb, solution-strengthened Cu-Ag-Zr, and ODS Cu-Al2O3, are being evaluated for oxidation resistance by static TGA exposures in low-p(O2) and cyclic oxidation in air, and by cyclic oxidation-reduction exposures (using air for oxidation and CO/CO2 or H2/Ar for reduction) to simulate expected service environments. The test protocol and results are presented.

  15. Plasma Protein Oxidation and Its Correlation with Antioxidant Potential During Human Aging

    PubMed Central

    Pandey, Kanti Bhooshan; Mehdi, Mohd Murtaza; Maurya, Pawan Kumar; Rizvi, Syed Ibrahim

    2010-01-01

    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. PMID:20826915

  16. ADVANCED OXIDATION: OXALATE DECOMPOSITION TESTING WITH OZONE

    SciTech Connect

    Ketusky, E.; Subramanian, K.

    2012-02-29

    At the Savannah River Site (SRS), oxalic acid is currently considered the preferred agent for chemically cleaning the large underground Liquid Radioactive Waste Tanks. It is applied only in the final stages of emptying a tank when generally less than 5,000 kg of waste solids remain, and slurrying based removal methods are no-longer effective. The use of oxalic acid is preferred because of its combined dissolution and chelating properties, as well as the fact that corrosion to the carbon steel tank walls can be controlled. Although oxalic acid is the preferred agent, there are significant potential downstream impacts. Impacts include: (1) Degraded evaporator operation; (2) Resultant oxalate precipitates taking away critically needed operating volume; and (3) Eventual creation of significant volumes of additional feed to salt processing. As an alternative to dealing with the downstream impacts, oxalate decomposition using variations of ozone based Advanced Oxidation Process (AOP) were investigated. In general AOPs use ozone or peroxide and a catalyst to create hydroxyl radicals. Hydroxyl radicals have among the highest oxidation potentials, and are commonly used to decompose organics. Although oxalate is considered among the most difficult organic to decompose, the ability of hydroxyl radicals to decompose oxalate is considered to be well demonstrated. In addition, as AOPs are considered to be 'green' their use enables any net chemical additions to the waste to be minimized. In order to test the ability to decompose the oxalate and determine the decomposition rates, a test rig was designed, where 10 vol% ozone would be educted into a spent oxalic acid decomposition loop, with the loop maintained at 70 C and recirculated at 40L/min. Each of the spent oxalic acid streams would be created from three oxalic acid strikes of an F-area simulant (i.e., Purex = high Fe/Al concentration) and H-area simulant (i.e., H area modified Purex = high Al/Fe concentration) after nearing

  17. Methionine Sulfoxide Reductases Preferentially Reduce Unfolded Oxidized Proteins and Protect Cells from Oxidative Protein Unfolding*

    PubMed Central

    Tarrago, Lionel; Kaya, Alaattin; Weerapana, Eranthie; Marino, Stefano M.; Gladyshev, Vadim N.

    2012-01-01

    Reduction of methionine sulfoxide (MetO) residues in proteins is catalyzed by methionine sulfoxide reductases A (MSRA) and B (MSRB), which act in a stereospecific manner. Catalytic properties of these enzymes were previously established mostly using low molecular weight MetO-containing compounds, whereas little is known about the catalysis of MetO reduction in proteins, the physiological substrates of MSRA and MSRB. In this work we exploited an NADPH-dependent thioredoxin system and determined the kinetic parameters of yeast MSRA and MSRB using three different MetO-containing proteins. Both enzymes showed Michaelis-Menten kinetics with the Km lower for protein than for small MetO-containing substrates. MSRA reduced both oxidized proteins and low molecular weight MetO-containing compounds with similar catalytic efficiencies, whereas MSRB was specialized for the reduction of MetO in proteins. Using oxidized glutathione S-transferase as a model substrate, we showed that both MSR types were more efficient in reducing MetO in unfolded than in folded proteins and that their activities increased with the unfolding state. Biochemical quantification and identification of MetO reduced in the substrates by mass spectrometry revealed that the increased activity was due to better access to oxidized MetO in unfolded proteins; it also showed that MSRA was intrinsically more active with unfolded proteins regardless of MetO availability. Moreover, MSRs most efficiently protected cells from oxidative stress that was accompanied by protein unfolding. Overall, this study indicates that MSRs serve a critical function in the folding process by repairing oxidatively damaged nascent polypeptides and unfolded proteins. PMID:22628550

  18. Potential disruption of protein-protein interactions by graphene oxide.

    PubMed

    Feng, Mei; Kang, Hongsuk; Yang, Zaixing; Luan, Binquan; Zhou, Ruhong

    2016-06-14

    Graphene oxide (GO) is a promising novel nanomaterial with a wide range of potential biomedical applications due to its many intriguing properties. However, very little research has been conducted to study its possible adverse effects on protein-protein interactions (and thus subsequent toxicity to human). Here, the potential cytotoxicity of GO is investigated at molecular level using large-scale, all-atom molecular dynamics simulations to explore the interaction mechanism between a protein dimer and a GO nanosheet oxidized at different levels. Our theoretical results reveal that GO nanosheet could intercalate between the two monomers of HIV-1 integrase dimer, disrupting the protein-protein interactions and eventually lead to dimer disassociation as graphene does [B. Luan et al., ACS Nano 9(1), 663 (2015)], albeit its insertion process is slower when compared with graphene due to the additional steric and attractive interactions. This study helps to better understand the toxicity of GO to cell functions which could shed light on how to improve its biocompatibility and biosafety for its wide potential biomedical applications. PMID:27306022

  19. Potential disruption of protein-protein interactions by graphene oxide

    NASA Astrophysics Data System (ADS)

    Feng, Mei; Kang, Hongsuk; Yang, Zaixing; Luan, Binquan; Zhou, Ruhong

    2016-06-01

    Graphene oxide (GO) is a promising novel nanomaterial with a wide range of potential biomedical applications due to its many intriguing properties. However, very little research has been conducted to study its possible adverse effects on protein-protein interactions (and thus subsequent toxicity to human). Here, the potential cytotoxicity of GO is investigated at molecular level using large-scale, all-atom molecular dynamics simulations to explore the interaction mechanism between a protein dimer and a GO nanosheet oxidized at different levels. Our theoretical results reveal that GO nanosheet could intercalate between the two monomers of HIV-1 integrase dimer, disrupting the protein-protein interactions and eventually lead to dimer disassociation as graphene does [B. Luan et al., ACS Nano 9(1), 663 (2015)], albeit its insertion process is slower when compared with graphene due to the additional steric and attractive interactions. This study helps to better understand the toxicity of GO to cell functions which could shed light on how to improve its biocompatibility and biosafety for its wide potential biomedical applications.

  20. Protein Quality Control Under Oxidative Stress Conditions

    PubMed Central

    Dahl, Jan-Ulrik; Gray, Michael J.; Jakob, Ursula

    2015-01-01

    Accumulation of reactive oxygen and chlorine species (RO/CS) is generally regarded to be a toxic and highly undesirable event, which serves as contributing factor in aging and many age-related diseases. However, it is also put to excellent use during host defense, when high levels of RO/CS are produced to kill invading microorganisms and regulate bacterial colonization. Biochemical and cell biological studies of how bacteria and other microorganisms deal with RO/CS have now provided important new insights into the physiological consequences of oxidative stress, the major targets that need protection, and the cellular strategies employed by organisms to mitigate the damage. This review examines the redox-regulated mechanisms by which cells maintain a functional proteome during oxidative stress. We will discuss the well-characterized redox-regulated chaperone Hsp33, and review recent discoveries demonstrating that oxidative stress-specific activation of chaperone function is a much more widespread phenomenon than previously anticipated. New members of this group include the cytosolic ATPase Get3 in yeast, the E. coli protein RidA, and the mammalian protein α2-macroglobin. We will conclude our review with recent evidence showing that inorganic polyphosphate (polyP), whose accumulation significantly increases bacterial oxidative stress resistance, works by a protein-like chaperone mechanism. Understanding the relationship between oxidative and proteotoxic stresses will improve our understanding of both host-microbe interactions and of how mammalian cells combat the damaging side effects of uncontrolled RO/CS production, a hallmark of inflammation. PMID:25698115

  1. Protein quality control under oxidative stress conditions.

    PubMed

    Dahl, Jan-Ulrik; Gray, Michael J; Jakob, Ursula

    2015-04-10

    Accumulation of reactive oxygen and chlorine species (RO/CS) is generally regarded to be a toxic and highly undesirable event, which serves as contributing factor in aging and many age-related diseases. However, it is also put to excellent use during host defense, when high levels of RO/CS are produced to kill invading microorganisms and regulate bacterial colonization. Biochemical and cell biological studies of how bacteria and other microorganisms deal with RO/CS have now provided important new insights into the physiological consequences of oxidative stress, the major targets that need protection, and the cellular strategies employed by organisms to mitigate the damage. This review examines the redox-regulated mechanisms by which cells maintain a functional proteome during oxidative stress. We will discuss the well-characterized redox-regulated chaperone Hsp33, and we will review recent discoveries demonstrating that oxidative stress-specific activation of chaperone function is a much more widespread phenomenon than previously anticipated. New members of this group include the cytosolic ATPase Get3 in yeast, the Escherichia coli protein RidA, and the mammalian protein α2-macroglobulin. We will conclude our review with recent evidence showing that inorganic polyphosphate (polyP), whose accumulation significantly increases bacterial oxidative stress resistance, works by a protein-like chaperone mechanism. Understanding the relationship between oxidative and proteotoxic stresses will improve our understanding of both host-microbe interactions and how mammalian cells combat the damaging side effects of uncontrolled RO/CS production, a hallmark of inflammation. PMID:25698115

  2. Steam Oxidation of Advanced Steam Turbine Alloys

    SciTech Connect

    Holcomb, Gordon R.

    2008-01-01

    Power generation from coal using ultra supercritical steam results in improved fuel efficiency and decreased greenhouse gas emissions. Results of ongoing research into the oxidation of candidate nickel-base alloys for ultra supercritical steam turbines are presented. Exposure conditions range from moist air at atmospheric pressure (650°C to 800°C) to steam at 34.5 MPa (650°C to 760°C). Parabolic scale growth coupled with internal oxidation and reactive evaporation of chromia are the primary corrosion mechanisms.

  3. Byonic: Advanced Peptide and Protein Identification Software

    PubMed Central

    Bern, Marshall; Kil, Yong J.; Becker, Christopher

    2013-01-01

    Byonic™ is the name of a software package for peptide and protein identification by tandem mass spectrometry. This software, which has only recently become commercially available, facilitates a much wider range of search possibilities than previous search software such as SEQUEST and Mascot. Byonic allows the user to define an essentially unlimited number of variable modification types. Byonic also allows the user to set a separate limit on the number of occurrences of each modification type, so that a search may consider only one or two chance modifications such as oxidations and deamidations per peptide, yet allow three or four biological modifications such as phosphorylations, which tend to cluster together. Hence Byonic can search for 10s or even 100s of modification types simultaneously without a prohibitively large combinatorial explosion. Byonic’s Wildcard Search™ allows the user to search for unanticipated or even unknown modifications alongside known modifications. Finally, Byonic’s Glycopeptide Search allows the user to identify glycopeptides without prior knowledge of glycan masses or glycosylation sites. PMID:23255153

  4. Advanced launch system. Advanced development oxidizer turbopump program

    NASA Astrophysics Data System (ADS)

    1993-10-01

    On May 19, 1989, Pratt & Whitney was awarded contract NAS8-37595 by the National Aeronautics and Space Administration, Marshall Space Flight Center, Huntsville Alabama for an Advanced Development Program (ADP) to design, develop and demonstrate a highly reliable low cost, liquid oxygen turbopump for the Advanced Launch System (ALS). The ALS had an overall goal of reducing the cost of placing payloads in orbit by an order of magnitude. This goal would require a substantial reduction in life cycle costs, with emphasis on recurring costs, compared to current launch vehicles. Engine studies supporting these efforts were made for the Space Transportation Main Engine (STME). The emphasis on low cost required design simplification of components and subsystems such that the ground maintenance and test operations was minimized. The results of the Oxygen Turbopump ADP technology effort would provide data to be used in the STME. Initially the STME baseline was a gas generator cycle engine with a vacuum thrust level of 580,000 lbf. This was later increased to 650,000 lbf and the oxygen turbopump design approach was changed to reflect the new thrust level. It was intended that this ADP program be conducted in two phases. Phase 1, a basic phase, would encompass the preliminary design effort, and Phase II, an optional contract phase to cover design, fabrication and test evaluation of an oxygen turbopump at a component test facility at the NASA John C. Stennis Space Center in Mississippi. The basic phase included preliminary design and analysis, evaluation of low cost concepts, and evaluation of fabrication techniques. The option phase included design of the pump and support hardware, analysis of the final configuration to ensure design integrity, fabrication of hardware to demonstrate low cost, DVS Testing of hardware to verify the design, assembly of the turbopump and full scale turbopump testing. In December 1990, the intent of this ADP to support the design and development was

  5. Advanced launch system. Advanced development oxidizer turbopump program

    NASA Technical Reports Server (NTRS)

    1993-01-01

    On May 19, 1989, Pratt & Whitney was awarded contract NAS8-37595 by the National Aeronautics and Space Administration, Marshall Space Flight Center, Huntsville Alabama for an Advanced Development Program (ADP) to design, develop and demonstrate a highly reliable low cost, liquid oxygen turbopump for the Advanced Launch System (ALS). The ALS had an overall goal of reducing the cost of placing payloads in orbit by an order of magnitude. This goal would require a substantial reduction in life cycle costs, with emphasis on recurring costs, compared to current launch vehicles. Engine studies supporting these efforts were made for the Space Transportation Main Engine (STME). The emphasis on low cost required design simplification of components and subsystems such that the ground maintenance and test operations was minimized. The results of the Oxygen Turbopump ADP technology effort would provide data to be used in the STME. Initially the STME baseline was a gas generator cycle engine with a vacuum thrust level of 580,000 lbf. This was later increased to 650,000 lbf and the oxygen turbopump design approach was changed to reflect the new thrust level. It was intended that this ADP program be conducted in two phases. Phase 1, a basic phase, would encompass the preliminary design effort, and Phase II, an optional contract phase to cover design, fabrication and test evaluation of an oxygen turbopump at a component test facility at the NASA John C. Stennis Space Center in Mississippi. The basic phase included preliminary design and analysis, evaluation of low cost concepts, and evaluation of fabrication techniques. The option phase included design of the pump and support hardware, analysis of the final configuration to ensure design integrity, fabrication of hardware to demonstrate low cost, DVS Testing of hardware to verify the design, assembly of the turbopump and full scale turbopump testing. In December 1990, the intent of this ADP to support the design and development was

  6. Directed molecular evolution to design advanced red fluorescent proteins

    PubMed Central

    Subach, Fedor V; Piatkevich, Kiryl D; Verkhusha, Vladislav V

    2015-01-01

    Fluorescent proteins have become indispensable imaging tools for biomedical research. continuing progress in fluorescence imaging, however, requires probes with additional colors and properties optimized for emerging techniques. Here we summarize strategies for development of red-shifted fluorescent proteins. We discuss possibilities for knowledge-based rational design based on the photochemistry of fluorescent proteins and the position of the chromophore in protein structure. We consider advances in library design by mutagenesis, protein expression systems and instrumentation for high-throughput screening that should yield improved fluorescent proteins for advanced imaging applications. PMID:22127219

  7. Protein Oxidation in Aging: Does It Play a Role in Aging Progression?

    PubMed Central

    Reeg, Sandra

    2015-01-01

    Abstract Significance: A constant accumulation of oxidized proteins takes place during aging. Oxidation of proteins leads to a partial unfolding and, therefore, to aggregation. Protein aggregates impair the activity of cellular proteolytic systems (proteasomes, lysosomes), resulting in further accumulation of oxidized proteins. In addition, the accumulation of highly crosslinked protein aggregates leads to further oxidant formation, damage to macromolecules, and, finally, to apoptotic cell death. Furthermore, protein oxidation seems to play a role in the development of various age-related diseases, for example, neurodegenerative diseases. Recent Advances: The highly oxidized lipofuscin accumulates during aging. Lipofuscin formation might cause impaired lysosomal and proteasomal degradation, metal ion accumulation, increased reactive oxygen species formation, and apoptosis. Critical Issues: It is still unclear to which extent protein oxidation is involved in the progression of aging and in the development of some age-related diseases. Future Directions: An extensive knowledge of the effects of protein oxidation on the aging process and its contribution to the development of age-related diseases could enable further strategies to reduce age-related impairments. Strategies aimed at lowering aggregate formation might be a straightforward intervention to reduce age-related malfunctions of organs. Antioxid. Redox Signal. 23, 239–255. PMID:25178482

  8. Oxidative Stress, Unfolded Protein Response, and Apoptosis in Developmental Toxicity

    PubMed Central

    Kupsco, Allison; Schlenk, Daniel

    2016-01-01

    Physiological development requires precise spatiotemporal regulation of cellular and molecular processes. Disruption of these key events can generate developmental toxicity in the form of teratogenesis or mortality. The mechanism behind many developmental toxicants remains unknown. While recent work has focused on the unfolded protein response (UPR), oxidative stress, and apoptosis in the pathogenesis of disease, few studies have addressed their relationship in developmental toxicity. Redox regulation, UPR, and apoptosis are essential for physiological development and can be disturbed by a variety of endogenous and exogenous toxicants to generate lethality and diverse malformations. This review examines the current knowledge of the role of oxidative stress, UPR, and apoptosis in physiological development as well as in developmental toxicity, focusing on studies and advances in vertebrates model systems. PMID:26008783

  9. Advanced metal oxide varistor concepts. Final report

    SciTech Connect

    Philipp, H.R.; Mahan, G.D.; Levinson, L.M.

    1984-07-01

    Zinc oxide varistors are ZnO-based ceramic semiconductor devices with highly nonlinear current-voltage characteristics similar to back-to-back Zener diodes but with much greater current, voltage, and energy-handling capabilities. Zinc oxide varistors have proven useful in a variety of applications, particularly as high-quality voltage suppression devices for the protection of ac and dc electric power transmission systems against the effects of transient overvoltages due to switching surges and lightning strikes. In the work described in this report, we have chosen to study simple varistor systems that use Bi or Pr as the varistor-forming additive and Co or Mn as the varistor-performance ingredient. Commercial varistor materials generally use Bi as the varistor-forming ingredient, and the sintering process in such material probably proceeds in the liquid phase. Varistor materials that use Pr as the varistor-forming ingredient are also produced commercially. However, owing to the high melting point of Pr/sub 2/O/sub 3/ compared to Bi/sub 2/O/sub 3/, sintering in these materials probably takes place in the solid state. The performance ingredients Co and Mn are present in almost all commercial mixes. Co is an interesting choice because it is known to introduce a deep level into ZnO, giving such varistors a green color.

  10. Recent advances of lanthanum-based perovskite oxides for catalysis

    SciTech Connect

    Zhu, Huiyuan; Zhang, Pengfei; Dai, Sheng

    2015-09-21

    There is a need to reduce the use of noble metal elements especially in the field of catalysis, where noble metals are ubiquitously applied. To this end, perovskite oxides, an important class of mixed oxide, have been attracting increasing attention for decades as potential replacements. Benefiting from the extraordinary tunability of their compositions and structures, perovskite oxides can be rationally tailored and equipped with targeted physical and chemical properties e.g. redox behavior, oxygen mobility, and ion conductivity for enhanced catalysis. Recently, the development of highly efficient perovskite oxide catalysts has been extensively studied. This review article summarizes the recent development of lanthanum-based perovskite oxides as advanced catalysts for both energy conversion applications and traditional heterogeneous reactions.

  11. Recent advances of lanthanum-based perovskite oxides for catalysis

    DOE PAGESBeta

    Zhu, Huiyuan; Zhang, Pengfei; Dai, Sheng

    2015-09-21

    There is a need to reduce the use of noble metal elements especially in the field of catalysis, where noble metals are ubiquitously applied. To this end, perovskite oxides, an important class of mixed oxide, have been attracting increasing attention for decades as potential replacements. Benefiting from the extraordinary tunability of their compositions and structures, perovskite oxides can be rationally tailored and equipped with targeted physical and chemical properties e.g. redox behavior, oxygen mobility, and ion conductivity for enhanced catalysis. Recently, the development of highly efficient perovskite oxide catalysts has been extensively studied. This review article summarizes the recent developmentmore » of lanthanum-based perovskite oxides as advanced catalysts for both energy conversion applications and traditional heterogeneous reactions.« less

  12. Advanced oxidation processes with coke plant wastewater treatment.

    PubMed

    Krzywicka, A; Kwarciak-Kozłowska, A

    2014-01-01

    The aim of this study was to determine the most efficient method of coke wastewater treatment. This research examined two processes - advanced oxidation with Fenton and photo-Fenton reaction. It was observed that the use of ultraviolet radiation with Fenton process had a better result in removal of impurities. PMID:24804662

  13. Advanced materials for solid oxide fuel cells

    SciTech Connect

    Armstrong, T.R.; Stevenson, J.

    1995-08-01

    The purpose of this research is to improve the properties of the current state-of-the-art materials used for solid oxide fuel cells (SOFCs). The objectives are to: (1) develop materials based on modifications of the state-of-the-art materials; (2) minimize or eliminate stability problems in the cathode, anode, and interconnect; (3) Electrochemically evaluate (in reproducible and controlled laboratory tests) the current state-of-the-art air electrode materials and cathode/electrolyte interfacial properties; (4) Develop accelerated electrochemical test methods to evaluate the performance of SOFCs under controlled and reproducible conditions; and (5) Develop and test materials for use in low-temperature SOFCs. The goal is to modify and improve the current state-of-the-art materials and minimize the total number of cations in each material to avoid negative effects on the materials properties. Materials to reduce potential deleterious interactions, (3) improve thermal, electrical, and electrochemical properties, (4) develop methods to synthesize both state-of-the-art and alternative materials for the simultaneous fabricatoin and consolidation in air of the interconnections and electrodes with the solid electrolyte, and (5) understand electrochemical reactions at materials interfaces and the effects of component composition and processing on those reactions.

  14. Advances in extrusion for texturized whey proteins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dairy proteins like whey proteins play an important role in human nutrition because of their characteristic structure and associated numerous benefits such as ease of digestion, in- vivo assimilation, creating new or maintaining the muscle mass and the unique ability of boosting immune functions. W...

  15. Oxidative Lipidomics Coming of Age: Advances in Analysis of Oxidized Phospholipids in Physiology and Pathology

    PubMed Central

    Pitt, Andrew R.

    2015-01-01

    Abstract Significance: Oxidized phospholipids are now well recognized as markers of biological oxidative stress and bioactive molecules with both pro-inflammatory and anti-inflammatory effects. While analytical methods continue to be developed for studies of generic lipid oxidation, mass spectrometry (MS) has underpinned the advances in knowledge of specific oxidized phospholipids by allowing their identification and characterization, and it is responsible for the expansion of oxidative lipidomics. Recent Advances: Studies of oxidized phospholipids in biological samples, from both animal models and clinical samples, have been facilitated by the recent improvements in MS, especially targeted routines that depend on the fragmentation pattern of the parent molecular ion and improved resolution and mass accuracy. MS can be used to identify selectively individual compounds or groups of compounds with common features, which greatly improves the sensitivity and specificity of detection. Application of these methods has enabled important advances in understanding the mechanisms of inflammatory diseases such as atherosclerosis, steatohepatitis, leprosy, and cystic fibrosis, and it offers potential for developing biomarkers of molecular aspects of the diseases. Critical Issues and Future Directions: The future in this field will depend on development of improved MS technologies, such as ion mobility, novel enrichment methods and databases, and software for data analysis, owing to the very large amount of data generated in these experiments. Imaging of oxidized phospholipids in tissue MS is an additional exciting direction emerging that can be expected to advance understanding of physiology and disease. Antioxid. Redox Signal. 22, 1646–1666. PMID:25694038

  16. Unraveling oxidation-induced modifications in proteins by proteomics.

    PubMed

    Panis, Carolina

    2014-01-01

    Oxidative stress-driven modifications can occur in lipids, proteins, and DNA and form the basis of several chronic pathologies. The metabolites generated during oxidative responses consist of very reactive substances that result in oxidative damage and modulation of redox signaling as the main outcomes. Oxidative modifications occurring in proteins are poorly understood; among the several methods employed to study such modifications, the most promising strategies are based on proteomics approaches. Proteomics has emerged as one of the most powerful and sensitive analytical tools for mapping the oxidative changes present in proteins in a wide range of sample types and disease models. This chapter addresses the main aspects of redox processes, including an overview of oxidative stress and its biological consequences on proteins. Moreover, major proteomic strategies that can be employed as powerful tools for understanding protein oxidative modifications detected in chronic pathologies are discussed, highlighting cancer research as a model. PMID:24629184

  17. Advanced Launch System advanced development oxidizer turbopump program: Technical implementation plan

    NASA Technical Reports Server (NTRS)

    Ferlita, F.

    1989-01-01

    The Advanced Launch Systems (ALS) Advanced Development Oxidizer Turbopump Program has designed, fabricated and demonstrated a low cost, highly reliable oxidizer turbopump for the Space Transportation Engine that minimizes the recurring cost for the ALS engines. Pratt and Whitney's (P and W's) plan for integrating the analyses, testing, fabrication, and other program efforts is addressed. This plan offers a comprehensive description of the total effort required to design, fabricate, and test the ALS oxidizer turbopump. The proposed ALS oxidizer turbopump reduces turbopump costs over current designs by taking advantage of design simplicity and state-of-the-art materials and producibility features without compromising system reliability. This is accomplished by selecting turbopump operating conditions that are within known successful operating regions and by using proven manufacturing techniques.

  18. Protein oxidative folding in the intermembrane mitochondrial space: more than protein trafficking.

    PubMed

    Fraga, Hugo; Ventura, Salvador

    2012-05-01

    The process of oxidative folding in the intermembrane mitochondrial space (IMS) is an exciting field of research because folding is simultaneously coupled to protein translocation and functional regulation. Contrary to the endoplasmatic reticulum ER where several chaperones of the disulfide isomerase family exist, oxidative folding in the IMS is exclusively catalyzed by the oxoreductase Mia40 that recognizes a group of proteins with characteristic cysteine motifs organized in twin CX(3)C, twin CX(9)C or CX(2)C motifs. In this review, we discuss the structural and biochemical studies leading to our current understanding of the Mia40 pathway as well as the open questions on the field. In fact, despite significant advances, several key points on the Mia40 pathway remain to clarify namely on the molecular mechanism trough which substrate oxidative folding is catalyzed. This issue is receiving increasing attention since failures in the import, sorting and folding of mitochondrial proteins is related to an increasing number of debilitating human disorders. PMID:22612783

  19. Nonspecific cleavage of proteins using graphene oxide.

    PubMed

    Lee, Heeyoung; Tran, Minh-Hai; Jeong, Hae Kyung; Han, Jinwoo; Jang, Sei-Heon; Lee, ChangWoo

    2014-04-15

    In this article, we report the intrinsic catalytic activity of graphene oxide (GO) for the nonspecific cleavage of proteins. We used bovine serum albumin (BSA) and a recombinant esterase (rEstKp) from the cold-adapted bacterium Pseudomonas mandelii as test proteins. Cleavage of BSA and rEstKp was nonspecific regarding amino acid sequence, but it exhibited dependence on temperature, time, and the amount of GO. However, cleavage of the proteins did not result in complete hydrolysis into their constituent amino acids. GO also invoked hydrolysis of p-nitrophenyl esters at moderate temperatures lower than those required for peptide hydrolysis regardless of chain length of the fatty acyl esters. Based on the results, the functional groups of GO, including alcohols, phenols, and carboxylates, can be considered as crucial roles in the GO-mediated hydrolysis of peptides and esters via general acid-base catalysis. Our findings provide novel insights into the role of GO as a carbocatalyst with nonspecific endopeptidase activity in biochemical reactions. PMID:24508487

  20. Protein secretion in Pichia pastoris and advances in protein production.

    PubMed

    Damasceno, Leonardo M; Huang, Chung-Jr; Batt, Carl A

    2012-01-01

    Yeast expression systems have been successfully used for over 20 years for the production of recombinant proteins. With the growing interest in recombinant protein expression for various uses, yeast expression systems, such as the popular Pichia pastoris, are becoming increasingly important. Although P. pastoris has been successfully used in the production of many secreted and intracellular recombinant proteins, there is still room for improvement of this expression system. In particular, secretion of recombinant proteins is still one of the main reasons for using P. pastoris. Therefore, endoplasmic reticulum protein folding, correct glycosylation, vesicular transport to the plasma membrane, gene dosage, secretion signal sequences, and secretome studies are important considerations for improved recombinant protein production. PMID:22057543

  1. Impact of leachate composition on the advanced oxidation treatment.

    PubMed

    Oulego, Paula; Collado, Sergio; Laca, Adriana; Díaz, Mario

    2016-01-01

    Advanced oxidation processes (AOPs) are gaining importance as an alternative to the biological or physicochemical treatments for the management of leachates. In this work, it has been studied the effect of the characteristics of the leachate (content in humic acids, landfill age and degree of stabilization) on the wet oxidation process and final quality of the treated effluent. A high concentration of humic acids in the leachate had a positive effect on the COD removal because this fraction is more easily oxidizable. Additionally, it has been demonstrated that the simultaneous presence of humic acid and the intermediates generated during the oxidation process improved the degradation of this acid, since such intermediates are stronger initiators of free radicals than the humic acid itself. Similar values of COD removals (49% and 51%) and biodegradability indices (0.30 and 0.35) were observed, after 8 h of wet oxidation, for the stabilised leachate (biologically pretreated) and the raw one, respectively. Nevertheless, final colour removal was much higher for the stabilised leachate, achieving values up to 91%, whereas for the raw one only 56% removal was attained for the same reaction time. Besides, wet oxidation treatment was more efficient for the young leachate than for the old one, with final COD conversions of 60% and 37%, respectively. Eventually, a triangular "three-lump" kinetic model, which considered direct oxidation to CO2 and partial oxidation through intermediate compounds, was here proposed. PMID:26517790

  2. Differential oxidative status and immune characterization of the early and advanced stages of human breast cancer.

    PubMed

    Panis, C; Victorino, V J; Herrera, A C S A; Freitas, L F; De Rossi, T; Campos, F C; Simão, A N Colado; Barbosa, D S; Pinge-Filho, P; Cecchini, R; Cecchini, A L

    2012-06-01

    Breast cancer is the malignant neoplasia with the highest incidence in women worldwide. Chronic oxidative stress and inflammation have been indicated as major mediators during carcinogenesis and cancer progression. Human studies have not considered the complexity of tumor biology during the stages of cancer advance, limiting their clinical application. The purpose of this study was to characterize systemic oxidative stress and immune response parameters in early (ED; TNM I and II) and advanced disease (AD; TNM III and IV) of patients diagnosed with infiltrative ductal carcinoma breast cancer. Oxidative stress parameters were evaluated by plasmatic lipoperoxidation, carbonyl content, thiobarbituric reactive substances (TBARS), nitric oxide levels (NO), total radical antioxidant parameter (TRAP), superoxide dismutase, and catalase activities and GSH levels. Immune evaluation was determined by TNF-α, IL-1β, IL-12, and IL-10 levels and leukocytes oxidative burst evaluation by chemiluminescence. Tissue damage analysis included heart (total CK and CKMB), liver (AST, ALT, GGT), and renal (creatinine, urea, and uric acid) plasmatic markers. C-reactive protein (CRP) and iron metabolism were also evaluated. Analysis of the results verified different oxidative stress statuses occur at distinct cancer stages. ED was characterized by reduction in catalase, 8-isoprostanes, and GSH levels, with enhanced lipid peroxidation and TBARS levels. AD exhibited more pronounced oxidative status, with reduction in catalase activity and TRAP, intense lipid peroxidation and high levels of NO, TBARs, and carbonyl content. ED patients presented a Th2 immune pattern, while AD exhibited Th1 status. CRP levels and ferritin were increased in both stages of disease. Leukocytes burst impairment was observed in both the groups. Plasma iron levels were significantly elevated in AD. The data obtained indicated that oxidative stress enhancement and immune response impairment may be necessary to ensure

  3. FNAS/advanced protein crystal growth

    NASA Technical Reports Server (NTRS)

    Rosenberger, Franz

    1992-01-01

    A scintillation method is presented for determination of the temperature dependence of the solubility, S(T), of proteins in 50-100 micro-l volumes of solution. S(T) data for lysozyme and horse serum albumin were obtained for various combinations of pH and precipitant concentrations. The resulting kinetics and equilibrium information was used for dynamic control, that is the separation of nucleation and growth stages in protein crystallization. Individual lysozyme and horse serum albumin crystals were grown in 15-20 micro-l solution volumes contained in x-ray capillaries.

  4. Evaluation of advanced oxidation process for the treatment of groundwater

    SciTech Connect

    Garland, S.B. II ); Peyton, G.R. ); Rice, L.E. . Kansas City Div.)

    1990-01-01

    An advanced oxidation process utilizing ozone, ultraviolet radiation, and hydrogen peroxide was selected for the removal of chlorinated hydrocarbons, particularly trichlorethene and 1,2-dichlorethene, from groundwater underlying the US Department of Energy Kansas City Plant. Since the performance of this process for the removal of organics from groundwater is not well-documented, an evaluation was initiated to determine the performance of the treatment plant, document the operation and maintenance costs experience, and evaluate contaminant removal mechanisms. 11 refs., 3 figs.

  5. Oxidation of alloys targeted for advanced steam turbines

    SciTech Connect

    Holcomb, G.R.; Covino, B.S., Jr.; Bullard, S.J.; Ziomek-Moroz, M.; Alman, D.E.

    2006-03-12

    Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include coal generation at 60% efficiency, which would require steam temperatures of up to 760°C. This research examines the steamside oxidation of alloys for use in USC systems, with emphasis placed on applications in high- and intermediate-pressure turbines.

  6. Oxidant/Antioxidant Balance in Animal Nutrition and Health: The Role of Protein Oxidation

    PubMed Central

    Celi, Pietro; Gabai, Gianfranco

    2015-01-01

    This review examines the role that oxidative stress (OS), and protein oxidation in particular, plays in nutrition, metabolism, and health of farm animals. The route by which redox homeostasis is involved in some important physiological functions and the implications of the impairment of oxidative status on animal health and diseases is also examined. Proteins have various and, at the same time, unique biological functions and their oxidation can result in structural changes and various functional modifications. Protein oxidation seems to be involved in pathological conditions, such as respiratory diseases and parasitic infection; however, some studies also suggest that protein oxidation plays a crucial role in the regulation of important physiological functions, such as reproduction, nutrition, metabolism, lactation, gut health, and neonatal physiology. As the characterization of the mechanisms by which OS may influence metabolism and health is attracting considerable scientific interest, the aim of this review is to present veterinary scientists and clinicians with various aspects of oxidative damage to proteins. PMID:26664975

  7. Alloys for advanced steam turbines--Oxidation behavior

    SciTech Connect

    Holcomb, G.R.

    2007-10-01

    Advanced or ultra supercritical (USC) steam power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy (DOE) include power generation from coal at 60% efficiency, which would require steam temperatures of up to 760°C. Current research on the oxidation of candidate materials for advanced steam turbines is presented with a focus on a methodology for estimating chromium evaporation rates from protective chromia scales. The high velocities and pressures of advanced steam turbines lead to evaporation predictions as high as 5 × 10-8 kg m-2s-1 of CrO2(OH)2(g) at 760°C and 34.5 MPa. This is equivalent to 0.077 mm per year of solid Cr loss.

  8. Protein Innovations Advance Drug Treatments, Skin Care

    NASA Technical Reports Server (NTRS)

    2012-01-01

    Dan Carter carefully layered the sheets of tracing paper on the light box. On each sheet were renderings of the atomic components of an essential human protein, one whose structure had long been a mystery. With each layer Carter laid down, a never-before-seen image became clearer. Carter joined NASA s Marshall Space Flight Center in 1985 and began exploring processes of protein crystal growth in space. By bouncing intense X-rays off the crystals, researchers can determine the electron densities around the thousands of atoms forming the protein molecules, unveiling their atomic structures. Cultivating crystals of sufficient quality on Earth was problematic; the microgravity conditions of space were far more accommodating. At the time, only a few hundred protein structures had been mapped, and the methods were time consuming and tedious. Carter hoped his work would help reveal the structure of human serum albumin, a major protein in the human circulatory system responsible for ferrying numerous small molecules in the blood. More was at stake than scientific curiosity. Albumin has a high affinity for most of the world s pharmaceuticals, Carter explains, and its interaction with drugs can change their safety and efficacy. When a medication enters the bloodstream a cancer chemotherapy drug, for example a majority of it can bind with albumin, leaving only a small percentage active for treatment. How a drug interacts with albumin can influence considerations like the necessary effective dosage, playing a significant role in the design and application of therapeutic measures. In spite of numerous difficulties, including having no access to microgravity following the 1986 Space Shuttle Challenger disaster, the image Carter had hoped to see was finally clarifying. In 1988, his lab had acquired specialized X-ray and detection equipment a tipping point. Carter and his colleagues began to piece together albumin s portrait, the formation of its electron densities coalescing on

  9. ELECTROCHEMICAL ADVANCED OXIDATION PROCESS UTILIZING NB-DOPED TIO2 ELECTRODES

    EPA Science Inventory

    An electrochemical advanced oxidation process has been developed utilizing electrodes which generate hydroxyl free radical (HO) by oxidizing water. All substrates tested are oxidized, mostly with reaction rates proportional to the corresponding rate constants for reaction with hy...

  10. ELECTROCHEMICAL ADVANCED OXIDATION PROCESS UTILIZING NB-DOPED TIO2 ELECTRODES

    EPA Science Inventory

    An electrochemical advanced oxidation process has been developed, utilizing electrodes which generate hydroxyl free radical (HO) by oxidizing water. All substrates tested are oxidized, mostly with reaction rates proportional to the corresponding rate constants for reaction with h...

  11. Brain protein deciphered at Advanced Light Source

    SciTech Connect

    2010-01-01

    This computer-generated model of a rat glutamate receptor is the first complete portrait of this important link in the nervous system. At the top of the Y-shaped protein, a pair of molecules splay outward like diverging prongs. The bottom section, which is embedded in a neuronal membrane, houses the ion channel. The resolution of this image is 3.6 angstroms per pixel, or just under four ten-billionths of a meter per image unit. http://newscenter.lbl.gov/feature-stories/2010/01/21/glutamate-receptor/

  12. Advanced oxidation of alkylphenol ethoxylates in aqueous systems.

    PubMed

    Nagarnaik, Pranav M; Boulanger, Bryan

    2011-10-01

    Alkylphenols and alkylphenol ethoxylates are ubiquitous wastewater contaminants. In this study the oxidation of nonylphenol ethoxylates (NPEO) and octylphenol ethoxylates (OPEO) by oxidant systems generating hydroxide radicals was evaluated. The reaction of each oxidant with a technical mixture of NPEO (Tergitol™) and OPEO (Triton X-100™) in ultrapure laboratory water and four aqueous environmental matrices was carried out in order to develop an understanding of reaction kinetics. The oxidation of APEOs was evaluated by hydroxyl radical generated by (1) hydrogen peroxide in the presence of ultraviolet light, (2) Fenton's reagent, and (3) a photo-Fenton's process. The second order kinetic rate constant for both NPEO and OPEO with hydroxyl radical was calculated to be 1.1×10¹⁰ M⁻¹ s⁻¹. The efficacy of the AOPs within an aqueous environmental matrix was dependent on the rate of formation of hydroxyl radical and the scavenging capacity of the matrix. A model based on the hydroxyl radical formation, scavenging capacity and the kinetic rate constant of target APEO was developed from the existing literature and applied to predict the concentration of APEOs in solution during advanced oxidation in different aqueous environmental matrices. PMID:21784502

  13. Advances in protein complex analysis using mass spectrometry.

    PubMed

    Gingras, Anne-Claude; Aebersold, Ruedi; Raught, Brian

    2005-02-15

    Proteins often function as components of larger complexes to perform a specific function, and formation of these complexes may be regulated. For example, intracellular signalling events often require transient and/or regulated protein-protein interactions for propagation, and protein binding to a specific DNA sequence, RNA molecule or metabolite is often regulated to modulate a particular cellular function. Thus, characterizing protein complexes can offer important insights into protein function. This review describes recent important advances in mass spectrometry (MS)-based techniques for the analysis of protein complexes. Following brief descriptions of how proteins are identified using MS, and general protein complex purification approaches, we address two of the most important issues in these types of studies: specificity and background protein contaminants. Two basic strategies for increasing specificity and decreasing background are presented: whereas (1) tandem affinity purification (TAP) of tagged proteins of interest can dramatically improve the signal-to-noise ratio via the generation of cleaner samples, (2) stable isotopic labelling of proteins may be used to discriminate between contaminants and bona fide binding partners using quantitative MS techniques. Examples, as well as advantages and disadvantages of each approach, are presented. PMID:15611014

  14. [Advances in fish antifreeze protein research].

    PubMed

    Zhong, Qi-Wang; Fan, Ting-Jun

    2002-03-01

    Antifreeze proteins (AFPs) can highly effectively protect cells and embryos from damages in freezing process by lowering the freezing points of their cytoplasmic matrix and body fluids in a noncolligative manner. Based on their origins and properties, AFPs have been classified into four types, i.e. type I, II, III and IV. Each of them possesses rather distinct characteristics both in structure and composition, although all of them have ability of lowering freezing points of fluids. AFPs' genes have been characterized as members of a multigene family and the levels of their mRNA synthesis vary significantly with seasons. Adsorption-inhibition operating at the ice surface is nowadays a hypothesis widely used to interpret the molecular mechanisms of noncolligative lowering of the freezing point, but the details of the mechanism on how the different types of AFP are adsorbed onto ice remain uncertain. Progresses in research on structures, amino acid compositions, genes, antifreeze mechanisms of the 4 distinct types of AFPs, and the application of the AFPs in cryopreservation of cells and embryos are reviewed here. PMID:12007008

  15. Definition study for temperature control in advanced protein crystal growth

    NASA Technical Reports Server (NTRS)

    Nyce, Thomas A.; Rosenberger, Franz; Sowers, Jennifer W.; Monaco, Lisa A.

    1990-01-01

    Some of the technical requirements for an expedient application of temperature control to advanced protein crystal growth activities are defined. Lysozome was used to study the effects of temperature ramping and temperature gradients for nucleation/dissolution and consecutive growth of sizable crystals and, to determine a prototype temperature program. The solubility study was conducted using equine serum albumin (ESA) which is an extremely stable, clinically important protein due to its capability to bind and transport many different small ions and molecules.

  16. Effect of metal catalyzed oxidation in recombinant viral protein assemblies

    PubMed Central

    2014-01-01

    Background Protein assemblies, such as virus-like particles, have increasing importance as vaccines, delivery vehicles and nanomaterials. However, their use requires stable assemblies. An important cause of loss of stability in proteins is oxidation, which can occur during their production, purification and storage. Despite its importance, very few studies have investigated the effect of oxidation in protein assemblies and their structural units. In this work, we investigated the role of in vitro oxidation in the assembly and stability of rotavirus VP6, a polymorphic protein. Results The susceptibility to oxidation of VP6 assembled into nanotubes (VP6NT) and unassembled VP6 (VP6U) was determined and compared to bovine serum albumin (BSA) as control. VP6 was more resistant to oxidation than BSA, as determined by measuring protein degradation and carbonyl content. It was found that assembly protected VP6 from in vitro metal-catalyzed oxidation. Oxidation provoked protein aggregation and VP6NT fragmentation, as evidenced by dynamic light scattering and transmission electron microscopy. Oxidative damage of VP6 correlated with a decrease of its center of fluorescence spectral mass. The in vitro assembly efficiency of VP6U into VP6NT decreased as the oxidant concentration increased. Conclusions Oxidation caused carbonylation, quenching, and destruction of aromatic amino acids and aggregation of VP6 in its assembled and unassembled forms. Such modifications affected protein functionality, including its ability to assemble. That assembly protected VP6 from oxidation shows that exposure of susceptible amino acids to the solvent increases their damage, and therefore the protein surface area that is exposed to the solvent is determinant of its susceptibility to oxidation. The inability of oxidized VP6 to assemble into nanotubes highlights the importance of avoiding this modification during the production of proteins that self-assemble. This is the first time that the role of

  17. Advancing the Development of Glycated Protein Biosensing Technology

    PubMed Central

    Kameya, Miho; Sakaguchi-Mikami, Akane; Ferri, Stefano; Tsugawa, Wakako; Sode, Koji

    2015-01-01

    Research advances in biochemical molecules have led to the development of convenient and reproducible biosensing molecules for glycated proteins, such as those based on the enzymes fructosyl amino acid oxidase (FAOX) or fructosyl peptide oxidase (FPOX). Recently, more attractive biosensing molecules with potential applications in next-generation biosensing of glycated proteins have been aggressively reported. We review 2 such molecules, fructosamine 6-kinase (FN6K) and fructosyl amino acid-binding protein, as well as their recent applications in the development of glycated protein biosensing systems. Research on FN6K and fructosyl amino acid-binding protein has been opening up new possibilities for the development of highly sensitive and proteolytic-digestion-free biosensing systems for glycated proteins. PMID:25627465

  18. A Nucleocytoplasmic Shuttling Protein in Oxidative Stress Tolerance

    SciTech Connect

    Ow, David W.; Song, Wen

    2003-03-26

    Plants for effective extraction of toxic metals and radionuclides must tolerate oxidative stress. To identify genes that enhance oxidative stress tolerance, an S. pombe cDNA expression plasmid library was screened for the ability to yield hypertolerant colonies. Here, we report on the properties of one gene that confers hypertolerance to cadmium and oxidizing chemicals. This gene appears to be conserved in other organisms as homologous genes are found in human, mouse, fruitfly and Arabidopsis. The fruitfly and Arabidopsis genes likewise enhance oxidative stress tolerance in fission yeast. During oxidative stress, the amount of mRNA does not change, but protein fusions to GFP relocate from the cytoplasm to the nucleus. The same pattern is observed with the Arabidopsis homologue-GFP fusion protein. This behavior suggests a signaling role in oxidative stress tolerance and these conserved proteins may be targets for engineering stress tolerant plants for phytoremediation.

  19. Overexpression of Catalase Diminishes Oxidative Cysteine Modifications of Cardiac Proteins

    PubMed Central

    Yao, Chunxiang; Behring, Jessica B.; Shao, Di; Sverdlov, Aaron L.; Whelan, Stephen A.; Elezaby, Aly; Yin, Xiaoyan; Siwik, Deborah A.; Seta, Francesca; Costello, Catherine E.; Cohen, Richard A.; Matsui, Reiko; Colucci, Wilson S.; McComb, Mark E.; Bachschmid, Markus M.

    2015-01-01

    Reactive protein cysteine thiolates are instrumental in redox regulation. Oxidants, such as hydrogen peroxide (H2O2), react with thiolates to form oxidative post-translational modifications, enabling physiological redox signaling. Cardiac disease and aging are associated with oxidative stress which can impair redox signaling by altering essential cysteine thiolates. We previously found that cardiac-specific overexpression of catalase (Cat), an enzyme that detoxifies excess H2O2, protected from oxidative stress and delayed cardiac aging in mice. Using redox proteomics and systems biology, we sought to identify the cysteines that could play a key role in cardiac disease and aging. With a ‘Tandem Mass Tag’ (TMT) labeling strategy and mass spectrometry, we investigated differential reversible cysteine oxidation in the cardiac proteome of wild type and Cat transgenic (Tg) mice. Reversible cysteine oxidation was measured as thiol occupancy, the ratio of total available versus reversibly oxidized cysteine thiols. Catalase overexpression globally decreased thiol occupancy by ≥1.3 fold in 82 proteins, including numerous mitochondrial and contractile proteins. Systems biology analysis assigned the majority of proteins with differentially modified thiols in Cat Tg mice to pathways of aging and cardiac disease, including cellular stress response, proteostasis, and apoptosis. In addition, Cat Tg mice exhibited diminished protein glutathione adducts and decreased H2O2 production from mitochondrial complex I and II, suggesting improved function of cardiac mitochondria. In conclusion, our data suggest that catalase may alleviate cardiac disease and aging by moderating global protein cysteine thiol oxidation. PMID:26642319

  20. Enzymatic iron oxidation by Leptothrix discophora: identification of an iron-oxidizing protein.

    PubMed Central

    Corstjens, P L; de Vrind, J P; Westbroek, P; de Vrind-de Jong, E W

    1992-01-01

    An iron-oxidizing factor was identified in the spent culture medium of the iron- and manganese-oxidizing bacterial strain Leptothrix discophora SS-1. It appeared to be a protein, with an apparent molecular weight of approximately 150,000. Its activity could be demonstrated after fractionation of the spent medium by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A spontaneous mutant of L. discophora SS-1 was isolated which excreted neither manganese- nor iron-oxidizing activity, whereas excretion of other proteins seemed to be unaffected. Although the excretion of both metal-oxidizing factors was probably linked, the difference in other properties suggests that manganese and iron oxidation represent two different pathways. With a dot-blot assay, it was established that different bacterial species have different metal-oxidizing capacities. Whereas L. discophora oxidized both iron and manganese, Sphaerotilus natans oxidized only iron and two Pseudomonas spp. oxidized only manganese. Images PMID:1610168

  1. Enzymatic iron oxidation by Leptothrix discophora: identification of an iron-oxidizing protein.

    PubMed

    Corstjens, P L; de Vrind, J P; Westbroek, P; de Vrind-de Jong, E W

    1992-02-01

    An iron-oxidizing factor was identified in the spent culture medium of the iron- and manganese-oxidizing bacterial strain Leptothrix discophora SS-1. It appeared to be a protein, with an apparent molecular weight of approximately 150,000. Its activity could be demonstrated after fractionation of the spent medium by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A spontaneous mutant of L. discophora SS-1 was isolated which excreted neither manganese- nor iron-oxidizing activity, whereas excretion of other proteins seemed to be unaffected. Although the excretion of both metal-oxidizing factors was probably linked, the difference in other properties suggests that manganese and iron oxidation represent two different pathways. With a dot-blot assay, it was established that different bacterial species have different metal-oxidizing capacities. Whereas L. discophora oxidized both iron and manganese, Sphaerotilus natans oxidized only iron and two Pseudomonas spp. oxidized only manganese. PMID:1610168

  2. Coupling Oxidative Signals to Protein Phosphorylation via Methionine Oxidation in Arabidopsis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The mechanisms involved in sensing oxidative signaling molecules such as H2O2 in plant and animal cells are not completely understood. In the present study, we tested the postulate that oxidation of methionine (Met) to Met sulfoxide (MetSO) can couple oxidative signals to changes in protein phosphor...

  3. Regulation of thrombosis and vascular function by protein methionine oxidation.

    PubMed

    Gu, Sean X; Stevens, Jeff W; Lentz, Steven R

    2015-06-18

    Redox biology is fundamental to both normal cellular homeostasis and pathological states associated with excessive oxidative stress. Reactive oxygen species function not only as signaling molecules but also as redox regulators of protein function. In the vascular system, redox reactions help regulate key physiologic responses such as cell adhesion, vasoconstriction, platelet aggregation, angiogenesis, inflammatory gene expression, and apoptosis. During pathologic states, altered redox balance can cause vascular cell dysfunction and affect the equilibrium between procoagulant and anticoagulant systems, contributing to thrombotic vascular disease. This review focuses on the emerging role of a specific reversible redox reaction, protein methionine oxidation, in vascular disease and thrombosis. A growing number of cardiovascular and hemostatic proteins are recognized to undergo reversible methionine oxidation, in which methionine residues are posttranslationally oxidized to methionine sulfoxide. Protein methionine oxidation can be reversed by the action of stereospecific enzymes known as methionine sulfoxide reductases. Calcium/calmodulin-dependent protein kinase II is a prototypical methionine redox sensor that responds to changes in the intracellular redox state via reversible oxidation of tandem methionine residues in its regulatory domain. Several other proteins with oxidation-sensitive methionine residues, including apolipoprotein A-I, thrombomodulin, and von Willebrand factor, may contribute to vascular disease and thrombosis. PMID:25900980

  4. Regulation of thrombosis and vascular function by protein methionine oxidation

    PubMed Central

    Gu, Sean X.; Stevens, Jeff W.

    2015-01-01

    Redox biology is fundamental to both normal cellular homeostasis and pathological states associated with excessive oxidative stress. Reactive oxygen species function not only as signaling molecules but also as redox regulators of protein function. In the vascular system, redox reactions help regulate key physiologic responses such as cell adhesion, vasoconstriction, platelet aggregation, angiogenesis, inflammatory gene expression, and apoptosis. During pathologic states, altered redox balance can cause vascular cell dysfunction and affect the equilibrium between procoagulant and anticoagulant systems, contributing to thrombotic vascular disease. This review focuses on the emerging role of a specific reversible redox reaction, protein methionine oxidation, in vascular disease and thrombosis. A growing number of cardiovascular and hemostatic proteins are recognized to undergo reversible methionine oxidation, in which methionine residues are posttranslationally oxidized to methionine sulfoxide. Protein methionine oxidation can be reversed by the action of stereospecific enzymes known as methionine sulfoxide reductases. Calcium/calmodulin-dependent protein kinase II is a prototypical methionine redox sensor that responds to changes in the intracellular redox state via reversible oxidation of tandem methionine residues in its regulatory domain. Several other proteins with oxidation-sensitive methionine residues, including apolipoprotein A-I, thrombomodulin, and von Willebrand factor, may contribute to vascular disease and thrombosis. PMID:25900980

  5. Advances in Polymer and Polymeric Nanostructures for Protein Conjugation

    PubMed Central

    González-Toro, Daniella C.; Thayumanavan, S.

    2013-01-01

    Linear polymers have been considered the best molecular structures for the formation of efficient protein conjugates due to their biological advantages, synthetic convenience and ease of functionalization. In recent years, much attention has been dedicated to develop synthetic strategies that produce the most control over protein conjugation utilizing linear polymers as scaffolds. As a result, different conjugate models, such as semitelechelic, homotelechelic, heterotelechelic and branched or star polymer conjugates, have been obtained that take advantage of these well-controlled synthetic strategies. Development of protein conjugates using nanostructures and the formation of said nanostructures from protein-polymer bioconjugates are other areas in the protein bioconjugation field. Although several polymer-protein technologies have been developed from these discoveries, few review articles have focused on the design and function of these polymers and nanostructures. This review will highlight some recent advances in protein-linear polymer technologies that employ protein covalent conjugation and successful protein-nanostructure bioconjugates (covalent conjugation as well) that have shown great potential for biological applications. PMID:24058205

  6. Advances in engineering of fluorescent proteins and photoactivatable proteins with red emission

    PubMed Central

    Piatkevich, Kiryl D.; Verkhusha, Vladislav V.

    2009-01-01

    Monomeric fluorescent proteins of different colors are widely used to study behavior and targeting of proteins in living cells. Fluorescent proteins that irreversibly change their spectral properties in response to light irradiation of a specific wavelength, or photoactivate, have become increasingly popular to image intracellular dynamics and super-resolution protein localization. Until recently, however, no optimized monomeric red fluorescent proteins and red photoactivatable proteins have been available. Furthermore, monomeric fluorescent proteins, which change emission from blue to red simply with time, so-called fluorescent timers, were developed to study protein age and turnover. Understanding of chemical mechanisms of the chromophore maturation or photoactivation into a red form will further advance engineering of fluorescent timers and photoactivatable proteins with enhanced and novel properties. PMID:19914857

  7. Quantifying Reversible Oxidation of Protein Thiols in Photosynthetic Organisms

    NASA Astrophysics Data System (ADS)

    Slade, William O.; Werth, Emily G.; McConnell, Evan W.; Alvarez, Sophie; Hicks, Leslie M.

    2015-04-01

    Photosynthetic organisms use dynamic post-translational modifications to survive and adapt, which include reversible oxidative modifications of protein thiols that regulate protein structure, function, and activity. Efforts to quantify thiol modifications on a global scale have relied upon peptide derivatization, typically using isobaric tags such as TMT, ICAT, or iTRAQ that are more expensive, less accurate, and provide less proteome coverage than label-free approaches—suggesting the need for improved experimental designs for studies requiring maximal coverage and precision. Herein, we present the coverage and precision of resin-assisted thiol enrichment coupled to label-free quantitation for the characterization of reversible oxidative modifications on protein thiols. Using C. reinhardtii and Arabidopsis as model systems for algae and plants, we quantified 3662 and 1641 unique cysteinyl peptides, respectively, with median coefficient of variation (CV) of 13% and 16%. Further, our method is extendable for the detection of protein abundance changes and stoichiometries of cysteine oxidation. Finally, we demonstrate proof-of-principle for our method, and reveal that exogenous hydrogen peroxide treatment regulates the C. reinhardtii redox proteome by increasing or decreasing the level of oxidation of 501 or 67 peptides, respectively. As protein activity and function is controlled by oxidative modifications on protein thiols, resin-assisted thiol enrichment coupled to label-free quantitation can reveal how intracellular and environmental stimuli affect plant survival and fitness through oxidative stress.

  8. Quantifying reversible oxidation of protein thiols in photosynthetic organisms.

    PubMed

    Slade, William O; Werth, Emily G; McConnell, Evan W; Alvarez, Sophie; Hicks, Leslie M

    2015-04-01

    Photosynthetic organisms use dynamic post-translational modifications to survive and adapt, which include reversible oxidative modifications of protein thiols that regulate protein structure, function, and activity. Efforts to quantify thiol modifications on a global scale have relied upon peptide derivatization, typically using isobaric tags such as TMT, ICAT, or iTRAQ that are more expensive, less accurate, and provide less proteome coverage than label-free approaches--suggesting the need for improved experimental designs for studies requiring maximal coverage and precision. Herein, we present the coverage and precision of resin-assisted thiol enrichment coupled to label-free quantitation for the characterization of reversible oxidative modifications on protein thiols. Using C. reinhardtii and Arabidopsis as model systems for algae and plants, we quantified 3662 and 1641 unique cysteinyl peptides, respectively, with median coefficient of variation (CV) of 13% and 16%. Further, our method is extendable for the detection of protein abundance changes and stoichiometries of cysteine oxidation. Finally, we demonstrate proof-of-principle for our method, and reveal that exogenous hydrogen peroxide treatment regulates the C. reinhardtii redox proteome by increasing or decreasing the level of oxidation of 501 or 67 peptides, respectively. As protein activity and function is controlled by oxidative modifications on protein thiols, resin-assisted thiol enrichment coupled to label-free quantitation can reveal how intracellular and environmental stimuli affect plant survival and fitness through oxidative stress. PMID:25698223

  9. Hypochlorite-induced oxidation of amino acids, peptides and proteins.

    PubMed

    Hawkins, C L; Pattison, D I; Davies, M J

    2003-12-01

    Activated phagocytes generate the potent oxidant hypochlorite (HOCl) via the release of the enzyme myeloperoxidase and hydrogen peroxide. HOCl is known to react with a number of biological targets including proteins, DNA, lipids and cholesterol. Proteins are likely to be major targets for reaction with HOCl within a cell due to their abundance and high reactivity with HOCl. This review summarizes information on the rate of reaction of HOCl with proteins, the nature of the intermediates formed, the mechanisms involved in protein oxidation and the products of these reactions. The predicted targets for reaction with HOCl from kinetic modeling studies and the consequences of HOCl-induced protein oxidation are also discussed. PMID:14661089

  10. Advanced Fluorescence Protein-Based Synapse-Detectors

    PubMed Central

    Lee, Hojin; Oh, Won Chan; Seong, Jihye; Kim, Jinhyun

    2016-01-01

    The complex information-processing capabilities of the central nervous system emerge from intricate patterns of synaptic input-output relationships among various neuronal circuit components. Understanding these capabilities thus requires a precise description of the individual synapses that comprise neural networks. Recent advances in fluorescent protein engineering, along with developments in light-favoring tissue clearing and optical imaging techniques, have rendered light microscopy (LM) a potent candidate for large-scale analyses of synapses, their properties, and their connectivity. Optically imaging newly engineered fluorescent proteins (FPs) tagged to synaptic proteins or microstructures enables the efficient, fine-resolution illumination of synaptic anatomy and function in large neural circuits. Here we review the latest progress in fluorescent protein-based molecular tools for imaging individual synapses and synaptic connectivity. We also identify associated technologies in gene delivery, tissue processing, and computational image analysis that will play a crucial role in bridging the gap between synapse- and system-level neuroscience. PMID:27445785

  11. Advanced Fluorescence Protein-Based Synapse-Detectors.

    PubMed

    Lee, Hojin; Oh, Won Chan; Seong, Jihye; Kim, Jinhyun

    2016-01-01

    The complex information-processing capabilities of the central nervous system emerge from intricate patterns of synaptic input-output relationships among various neuronal circuit components. Understanding these capabilities thus requires a precise description of the individual synapses that comprise neural networks. Recent advances in fluorescent protein engineering, along with developments in light-favoring tissue clearing and optical imaging techniques, have rendered light microscopy (LM) a potent candidate for large-scale analyses of synapses, their properties, and their connectivity. Optically imaging newly engineered fluorescent proteins (FPs) tagged to synaptic proteins or microstructures enables the efficient, fine-resolution illumination of synaptic anatomy and function in large neural circuits. Here we review the latest progress in fluorescent protein-based molecular tools for imaging individual synapses and synaptic connectivity. We also identify associated technologies in gene delivery, tissue processing, and computational image analysis that will play a crucial role in bridging the gap between synapse- and system-level neuroscience. PMID:27445785

  12. The analysis of protein pharmaceuticals: near future advances.

    PubMed

    Middaugh, C R

    1994-01-01

    The analysis of protein pharmaceuticals currently involves a complex series of chromatographic, electrophoretic, spectroscopic, immunological and biological measurements to unequivocally establish their identity, purity and integrity. In this review, I briefly consider the possibility that at least the functional identity and integrity of a protein drug might be established by either a single analysis involving X-ray diffraction, NMR or mass spectrometry, or by a chromatographically based multi-detector system in which a number of critical parameters are essentially simultaneously determined. The use of a protein standard to obtain comparative measurements and new advances in the technology of each of these methods is emphasized. A current major obstacle to the implementation of these approaches is the frequent microheterogeneity of protein preparations. The evolution of biological assays into measurements examining more defined intracellular signal transduction events or based on novel biosensors as well as the analysis of vaccines is also briefly discussed. PMID:7765931

  13. Structural Basis of Protein Oxidation Resistance: A Lysozyme Study

    PubMed Central

    Girod, Marion; Enjalbert, Quentin; Brunet, Claire; Antoine, Rodolphe; Lemoine, Jérôme; Lukac, Iva; Radman, Miroslav; Krisko, Anita; Dugourd, Philippe

    2014-01-01

    Accumulation of oxidative damage in proteins correlates with aging since it can cause irreversible and progressive degeneration of almost all cellular functions. Apparently, native protein structures have evolved intrinsic resistance to oxidation since perfectly folded proteins are, by large most robust. Here we explore the structural basis of protein resistance to radiation-induced oxidation using chicken egg white lysozyme in the native and misfolded form. We study the differential resistance to oxidative damage of six different parts of native and misfolded lysozyme by a targeted tandem/mass spectrometry approach of its tryptic fragments. The decay of the amount of each lysozyme fragment with increasing radiation dose is found to be a two steps process, characterized by a double exponential evolution of their amounts: the first one can be largely attributed to oxidation of specific amino acids, while the second one corresponds to further degradation of the protein. By correlating these results to the structural parameters computed from molecular dynamics (MD) simulations, we find the protein parts with increased root-mean-square deviation (RMSD) to be more susceptible to modifications. In addition, involvement of amino acid side-chains in hydrogen bonds has a protective effect against oxidation Increased exposure to solvent of individual amino acid side chains correlates with high susceptibility to oxidative and other modifications like side chain fragmentation. Generally, while none of the structural parameters alone can account for the fate of peptides during radiation, together they provide an insight into the relationship between protein structure and susceptibility to oxidation. PMID:24999730

  14. POSSIBLE LINK BETWEEN METHIONINE OXIDATION AND PROTEIN PHOSPHORYLATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aerobic metabolism leads to the production of reactive oxygen species that may damage proteins. Methionine residues in proteins are particularly susceptible to oxidation to methionine sulfoxide (MetSO) converting its side chain from hydrophobic to hydrophilic. We postulated that this could have a si...

  15. Modeling the oxidation of methionine residues by peroxides in proteins.

    PubMed

    Chennamsetty, Naresh; Quan, Yong; Nashine, Vishal; Sadineni, Vikram; Lyngberg, Olav; Krystek, Stanley

    2015-04-01

    We report the use of molecular modeling to predict the oxidation propensity of methionine residues in proteins. Oxidation of methionine to the sulfoxide form is one of the major degradation pathways for therapeutic proteins. Oxidation can occur during production, formulation, or storage of pharmaceuticals and it often reduces or eliminates biological activity. We use a molecular model based on atomistic simulations called 2-shell water coordination number to predict the oxidation rates for several model proteins and therapeutic candidates. In addition, we implement models that are based on static and simulation average of the solvent-accessible area (SAA) for either the side chain or the sulfur atom in the methionine residue. We then compare the results from the different models against the experimentally measured relative rates of methionine oxidation. We find that both the 2-shell model and the simulation-averaged SAA models are accurate in predicting the oxidation propensity of methionine residues for the proteins tested. We also find the appropriate parameter ranges where the models are most accurate. These models have significant predictive power and can be used to enable further protein engineering or to guide formulation approaches in stabilizing the unstable methionine residues. PMID:25641333

  16. Blot-MS of Carbonylated Proteins: A Tool to Identify Oxidized Proteins.

    PubMed

    Ferreira, Rita; Domingues, Pedro; Amado, Francisco; Vitorino, Rui

    2016-01-01

    The efficiency of proteostasis regulation declines during aging and the failure of protein homeostasis is common in age-related diseases. Protein oxidation is a major contributor to the loss of proteome homeostasis, also called "proteostasis," precluding protein misfolding and aggregation. So, the identification of the molecular pathways impaired by protein oxidation will increase the understanding of proteostasis and the pathophysiological conditions related to the loss of proteostasis. Sample derivatization with dinitrophenyl hydrazine and western blot immunoassay detection of carbonylated proteins (commonly known as Oxyblot™) coupled to mass spectrometry (blot-MS) is an attractive methodological approach to identify proteins that are more prone to carbonylation, a typical oxidative modification of amino acid residues. The integration of blot-MS data of carbonylated proteins with bioinformatics tools allows the identification of the biological processes more affected by protein oxidation and that, eventually, result in the loss of proteostasis.In this chapter, we describe a blot-MS methodology to identify the proteins more prone to oxidation in biological samples, as cell and tissue extracts, and biofluids. Analysis of mitochondria isolated from cardiac tissue is provided as an example. Bioinformatic strategy to deal with data retrieved from blot-MS experiments are proposed for the identification of relevant biological processes modulated by oxidative stress stimuli. PMID:27613049

  17. Oxidative stress and mitochondrial protein quality control in aging.

    PubMed

    Lionaki, Eirini; Tavernarakis, Nektarios

    2013-10-30

    Mitochondrial protein quality control incorporates an elaborate network of chaperones and proteases that survey the organelle for misfolded or unfolded proteins and toxic aggregates. Repair of misfolded or aggregated protein and proteolytic removal of irreversibly damaged proteins are carried out by the mitochondrial protein quality control system. Initial maturation and folding of the nuclear or mitochondrial-encoded mitochondrial proteins are mediated by processing peptidases and chaperones that interact with the protein translocation machinery. Mitochondrial proteins are subjected to cumulative oxidative damage. Thus, impairment of quality control processes may cause mitochondrial dysfunction. Aging has been associated with a marked decline in the effectiveness of mitochondrial protein quality control. Here, we present an overview of the chaperones and proteases involved in the initial folding and maturation of new, incoming precursor molecules, and the subsequent repair and removal of oxidized aggregated proteins. In addition, we highlight the link between mitochondrial protein quality control mechanisms and the aging process. This article is part of a Special Issue entitled: Posttranslational Protein modifications in biology and Medicine. PMID:23563202

  18. Protein Sulfenylation: A Novel Readout of Environmental Oxidant Stress

    PubMed Central

    Wages, Phillip A.; Lavrich, Katelyn S.; Zhang, Zhenfa; Cheng, Wan-Yun; Corteselli, Elizabeth; Gold, Avram; Bromberg, Philip; Simmons, Steven O.; Samet, James M.

    2016-01-01

    Oxidative stress is a commonly cited mechanism of toxicity of environmental agents. Ubiquitous environmental chemicals such as the diesel exhaust component 1,2-naphthoquinone (1,2-NQ) induce oxidative stress by redox cycling, which generates hydrogen peroxide (H2O2). Cysteinyl thiolate residues on regulatory proteins are subjected to oxidative modification by H2O2 in physiological contexts and are also toxicological targets of oxidant stress induced by environmental contaminants. We investigated whether exposure to environmentally relevant concentrations of 1,2-NQ can induce H2O2-dependent oxidation of cysteinyl thiols in regulatory proteins as a readout of oxidant stress in human airway epithelial cells. BEAS-2B cells were exposed to 0–1000 μM 1,2-NQ for 0–30 min, and levels of H2O2 were measured by ratiometric spectrofluorometry of HyPer. H2O2-dependent protein sulfenylation was measured using immunohistochemistry, immunoblotting, and isotopic mass spectrometry. Catalase overexpression was used to investigate the relationship between H2O2 generation and protein sulfenylation in cells exposed to 1,2-NQ. Multiple experimental approaches showed that exposure to 1,2-NQ at concentrations as low as 3 μM induces H2O2-dependent protein sulfenylation in BEAS-2B cells. Moreover, the time of onset and duration of 1,2-NQ-induced sulfenylation of the regulatory proteins GAPDH and PTP1B showed significant differences. Oxidative modification of regulatory cysteinyl thiols in human lung cells exposed to relevant concentrations of an ambient air contaminant represents a novel marker of oxidative environmental stress. PMID:26605980

  19. Lipid and Protein Oxidation in Newborn Infants after Lutein Administration

    PubMed Central

    Perrone, S.; Tei, M.; Longini, M.; Santacroce, A.; Turrisi, G.; Proietti, F.; Felici, C.; Picardi, A.; Bazzini, F.; Vasarri, P.; Buonocore, G.

    2014-01-01

    Objectives. To test the hypothesis that neonatal supplementation with lutein in the first hours of life reduces neonatal oxidative stress (OS) in the immediate postpartum period. Methods. A randomized controlled, double-blinded clinical trial was conducted among 150 newborns divided into control group, not supplemented (n = 47), and test group, supplemented with lutein on the first day postpartum (n = 103). Blood Samples were collected at birth from cord and at 48 hrs postpartum while routine neonatal metabolic screenings were taking place. Total hydroperoxide (TH), advanced oxidation protein products (AOPP), and biological antioxidant potential (BAP) were measured by spectrophotometry and data were analyzed by Wilcoxon rank sum test and by multivariate logistic regression analysis. Results. Before lutein supplementation, the mean blood concentrations of AOPP, TH, and BAP were 36.10 umol/L, 156.75 mmol/H2O2, and 2361.04 umol/L in the test group. After lutein supplementation, significantly higher BAP increment (0.17 ± 0.22 versus 0.06 versus ± 0.46) and lower TH increment (0.46 ± 0.54 versus 0.34 ± 0.52) were observed in the test group compared to controls. Conclusion. Neonatal supplementation with lutein in the first hours of life increases BAP and reduces TH in supplemented babies compared to those untreated. The generation of free radical-induced damage at birth is reduced by lutein. This trial is registered with ClinicalTrials.gov NCT02068807. PMID:24876916

  20. Markers of protein oxidation by hydroxyl radical and reactive nitrogen species in tissues of aging rats.

    PubMed

    Leeuwenburgh, C; Hansen, P; Shaish, A; Holloszy, J O; Heinecke, J W

    1998-02-01

    Many lines of evidence implicate oxidative damage in aging. Possible pathways include reactions that modify aromatic amino acid residues on proteins. o-Tyrosine is a stable marker for oxidation of protein-bound phenylalanine by hydroxyl radical, whereas 3-nitrotyrosine is a marker for oxidation of protein-bound tyrosine by reactive nitrogen species. To test the hypothesis that proteins damaged by hydroxyl radical and reactive nitrogen accumulate with aging, we used isotope dilution gas chromatography-mass spectrometry to measure levels of o-tyrosine and 3-nitrotyrosine in heart, skeletal muscle, and liver from young adult (9 mo) and old (24 mo) female Long-Evans/Wistar hybrid rats. We also measured these markers in young adult and old rats that received antioxidant supplements (alpha-tocopherol, beta-carotene, butylated hydroxytoluene, and ascorbic acid) from the age of 5 mo. We found that aging did not significantly increase levels of protein-bound o-tyrosine or 3-nitrotyrosine in any of the tissues. Antioxidant supplementation had no effect on the levels of protein-bound o-tyrosine and 3-nitrotyrosine in either young or old animals. These observations indicate that the o-tyrosine and 3-nitrotyrosine do not increase significantly in heart, skeletal muscle, and liver in old rats, suggesting that proteins damaged by hydroxyl radical and reactive nitrogen species do not accumulate in these tissues with advancing age. PMID:9486304

  1. Oxidative Stress Impairs the Stimulatory Effect of S100 Proteins on Protein Phosphatase 5 Activity.

    PubMed

    Yamaguchi, Fuminori; Tsuchiya, Mitsumasa; Shimamoto, Seiko; Fujimoto, Tomohito; Tokumitsu, Hiroshi; Tokuda, Masaaki; Kobayashi, Ryoji

    2016-01-01

    Oxidative stress is the consequence of an imbalance between the production of harmful reactive oxygen species and the cellular antioxidant system for neutralization, and it activates multiple intracellular signaling pathways, including apoptosis signal-regulating kinase 1 (ASK1). Protein phosphatase 5 (PP5) is a serine/threonine phosphatase involved in oxidative stress responses. Previously, we reported that S100 proteins activate PP5 in a calcium-dependent manner. S100 proteins belong to a family of small EF-hand calcium-binding proteins involved in many processes such as cell proliferation, differentiation, apoptosis, and inflammation. Therefore, we investigated the effects of oxidative stress on S100 proteins, their interaction with PP5, and PP5 enzyme activity. Recombinant S100A2 was easily air-oxidized or Cu-oxidized, and oxidized S100A2 formed cross-linked dimers and higher molecular-mass complexes. The binding of oxidized S100A2 to PP5 was reduced, resulting in decreased PP5 activation in vitro. Oxidation also impaired S100A1, S100A6, S100B, and S100P to activate PP5, although the low dose of oxidized S100 proteins still activated PP5. Hydrogen peroxide (H2O2) induced S100A2 oxidation in human keratinocytes (HaCaT) and human hepatocellular carcinoma (Huh-7) cells. Furthermore, H2O2 reduced the binding of S100A2 to PP5 and decreased PP5 activation in HaCaT and Huh-7 cells. Importantly, even the low dose of S100A2 achieved by knocking down increased dephosphorylation of ASK1 and reduced caspase 3/7 activity in Huh-7 cells treated with H2O2. These results indicate that oxidative stress impairs the ability of S100 proteins to bind and activate PP5, which in turn modulates the ASK1-mediated signaling cascades involved in apoptosis. PMID:27600583

  2. Myeloperoxidase-mediated protein oxidation: its possible biological functions.

    PubMed

    Naskalski, Jerzy W; Marcinkiewicz, Janusz; Drozdz, Ryszard

    2002-05-01

    Oxidation of proteins occurs both as a side-effect of aerobic energy metabolism and as an effect of specific metabolism of phagocytic polymorphonuclear granulocytes producing O2- and H2O2. In contrast to other cells, which control their H2O2 level by degrading it to O2 and H2O, polymorphonuclear neutrophilic leukocytes (PMN) use H2O2 as a substrate for oxidizing chloride ions to HOCl which rapidly react with all neighboring thiol, disulfide and amino residues. Chloramines, which are the most abundant HOCl reaction products, react with proteins, modifying only certain exposed methionine and cysteine residues. This may account for selective inactivation of a number of enzymes, carrier proteins and peptide mediators, including the alpha1-proteinase inhibitor, alpha2-macroglobulin and plasminogen activator inhibitor. Inactivaton of plasma proteinase inhibitors protects PMN elastase, collagenase, cathepsin G and other serine proteases in the inflammatory foci. This promotes proteolytic degradation of damaged tissue, removal of bacterial debris and wound healing, as well as tissue remodeling related to the inflammatory processes. Oxidative control of protease-anti-protease balance affects the development of the inflammatory processes. Moreover, inactivation of plasma proteinase inhibitors facilitates primary antigen processing, upregulates lymphocyte proliferative response and activates the local immune response. Oxidation produces a specific protein tagging which attracts and stimulates immune active cells. Therefore, humoral response against oxidatively modified proteins occurs more effectively than that of the native proteins. The effect is dose-dependent with respect to the amount of oxidant employed. Glycol aldehyde, which is the serine chloramine spontaneous decay product, in mice immunized with glycol aldehyde-modified egg-white albumin, yields specific IgG production manifold higher than that in mice immunized with native albumin. Immunopotentiation is produced

  3. ER Protein Processing Under Oxidative Stress: Implications and Prevention.

    PubMed

    Khalil, Mahmoud F; Valenzuela, Carlos; Sisniega, Daniella; Skouta, Rachid; Narayan, Mahesh

    2016-06-01

    Elevated levels of mitochondrial nitrosative stress have been associated with the pathogenesis of both Parkinson's and Alzheimer's diseases. The mechanism involves catalytic poisoning of the endoplasmic reticulum (ER)-resident oxidoreductase chaperone, protein disulfide isomerase (PDI), and the subsequent accumulation of ER-processed substrate proteins. Using a model system to mimic mitochondrial oxidative and nitrosative stress, we demonstrate a PDI-independent mechanism whereby reactive oxygen species (ROS) compromise regeneration rates of disulfide bond-containing ER-processed proteins. Under ROS-duress, the secretion-destined traffic adopts disulfide-exposed structures making the protein flux retrotranslocation biased. We also demonstrate that ROS-compromised protein maturation rates can be rescued by the polyphenol ellagic acid (EA). Our results are significant in that they reveal an additional mechanism which could promote neurodegenerative disorders. Furthermore, our data reveal that EA possesses therapeutic potential as a lead prophylactic agent against oxidative/nitrosative stress-related neurodegenerative diseases. PMID:26983927

  4. Advances in Protein NMR Impacting Drug Discovery Provided by the NIGMS Protein Structure Initiative

    PubMed Central

    Montelione, Gaetano T.; Szyperski, Thomas

    2014-01-01

    Rational drug design relies on three-dimensional structures of biological macromolecules, especially proteins. Structural genomics high-throughput (HTP) structure determination platforms established by the NIH Protein Structure Initiative are uniquely suited to provide these structures. NMR plays a critical role since (i) many important protein targets do not form single crystals required for X-ray diffraction and (ii) NMR can provide valuable structural and dynamic information on proteins and their drug complexes that cannot be obtained with X-ray crystallography. In this article, recent advances of NMR driven by structural genomics projects are reviewed. These advances promise that future pharmaceutical discovery and design of drugs can increasingly rely on protocols for rapid and accurate NMR structure determination. PMID:20443167

  5. Oxidation of methionine residues in proteins of activated human neutrophils.

    PubMed Central

    Fliss, H; Weissbach, H; Brot, N

    1983-01-01

    A simple assay for the detection of 35S-labeled methionine sulfoxide residues in proteins is described. The assay, which is based on the ability of CNBr to react with methionine but not with methionine sulfoxide, requires the prelabeling of cellular proteins with [35S]methionine. The assay was used to study the extent of methionine oxidation in newly synthesized proteins of both activated and quiescent human neutrophils. In cells undergoing a phorbol 12-myristate 13-acetate-induced respiratory burst, about 66% of all methionine residues in newly synthesized proteins were oxidized to the sulfoxide derivative, as compared with 9% in cells not treated with the phorbol ester. In contrast, quantitation of methionine sulfoxide content in the total cellular protein by means of amino acid analysis showed that only 22% of all methionine residues were oxidized in activated cells as compared with 9% in quiescent cells. It is proposed that methionine residues in nascent polypeptide chains are more susceptible to oxidation than those in completed proteins. PMID:6580633

  6. Treatment of real industrial wastewater using the combined approach of advanced oxidation followed by aerobic oxidation.

    PubMed

    Ramteke, Lokeshkumar P; Gogate, Parag R

    2016-05-01

    Fenton oxidation and ultrasound-based pretreatment have been applied to improve the treatment of real industrial wastewater based on the use of biological oxidation. The effect of operating parameters such as Fe(2+) loading, contact time, initial pH, and hydrogen peroxide loading on the extent of chemical oxygen demand (COD) reduction and change in biochemical oxygen demand (BOD5)/COD ratio has been investigated. The optimum operating conditions established for the pretreatment were initial pH of 3.0, Fe(2+) loading of 2.0, and 2.5 g L(-1) for the US/Fenton/stirring and Fenton approach, respectively, and temperature of 25 °C with initial H2O2 loading of 1.5 g L(-1). The use of pretreatment resulted in a significant increase in the BOD5/COD ratio confirming the production of easily digestible intermediates. The effect of the type of sludge in the aerobic biodegradation was also investigated based on the use of primary activated sludge (PAS), modified activated sludge (MAS), and activated sludge (AS). Enhanced removal of the pollutants as well as higher biomass yield was observed for MAS as compared to PAS and AS. The use of US/Fenton/stirring pretreatment under the optimized conditions followed by biological oxidation using MAS resulted in maximum COD removal at 97.9 %. The required hydraulic retention time for the combined oxidation system was also significantly lower as compared to only biological oxidation operation. Kinetic studies revealed that the reduction in the COD followed a first-order kinetic model for advanced oxidation and pseudo first-order model for biodegradation. The study clearly established the utility of the combined technology for the effective treatment of real industrial wastewater. PMID:26846248

  7. Protein-bound acrolein: Potential markers for oxidative stress

    PubMed Central

    Uchida, Koji; Kanematsu, Masamichi; Sakai, Kensuke; Matsuda, Tsukasa; Hattori, Nobutaka; Mizuno, Yoshikuni; Suzuki, Daisuke; Miyata, Toshio; Noguchi, Noriko; Niki, Etsuo; Osawa, Toshihiko

    1998-01-01

    Acrolein (CH2=CH—CHO) is known as a ubiquitous pollutant in the environment. Here we show that this notorious aldehyde is not just a pollutant, but also a lipid peroxidation product that could be ubiquitously generated in biological systems. Upon incubation with BSA, acrolein was rapidly incorporated into the protein and generated the protein-linked carbonyl derivative, a putative marker of oxidatively modified proteins under oxidative stress. To verify the presence of protein-bound acrolein in vivo, the mAb (mAb5F6) against the acrolein-modified keyhole limpet hemocyanin was raised. It was found that the acrolein-lysine adduct, Nɛ-(3-formyl-3,4-dehydropiperidino)lysine, constitutes an epitope of the antibody. Immunohistochemical analysis of atherosclerotic lesions from a human aorta demonstrated that antigenic materials recognized by mAb5F6 indeed constituted the lesions, in which intense positivity was associated primarily with macrophage-derived foam cells and the thickening neointima of arterial walls. The observations that (i) oxidative modification of low-density lipoprotein with Cu2+ generated the acrolein-low-density lipoprotein adducts and (ii) the iron-catalyzed oxidation of arachidonate in the presence of protein resulted in the formation of antigenic materials suggested that polyunsaturated fatty acids are sources of acrolein that cause the production of protein-bound acrolein. These data suggest that the protein-bound acrolein represents potential markers of oxidative stress and long-term damage to protein in aging, atherosclerosis, and diabetes. PMID:9560197

  8. Aqueous Oxidative Heck Reaction as a Protein-Labeling Strategy

    PubMed Central

    Ourailidou, Maria Eleni; van der Meer, Jan-Ytzen; Baas, Bert-Jan; Jeronimus-Stratingh, Margot; Gottumukkala, Aditya L; Poelarends, Gerrit J; Minnaard, Adriaan J; Dekker, Frank J

    2014-01-01

    An increasing number of chemical reactions are being employed for bio-orthogonal ligation of detection labels to protein-bound functional groups. Several of these strategies, however, are limited in their application to pure proteins and are ineffective in complex biological samples such as cell lysates. Here we present the palladium-catalyzed oxidative Heck reaction as a new and robust bio-orthogonal strategy for linking functionalized arylboronic acids to protein-bound alkenes in high yields and with excellent chemoselectivity even in the presence of complex protein mixtures from living cells. Advantageously, this reaction proceeds under aerobic conditions, whereas most other metal-catalyzed reactions require inert atmosphere. PMID:24376051

  9. Oxidative Stress to the Cornea, Changes in Corneal Optical Properties, and Advances in Treatment of Corneal Oxidative Injuries

    PubMed Central

    Cejka, Cestmir; Cejkova, Jitka

    2015-01-01

    Oxidative stress is involved in many ocular diseases and injuries. The imbalance between oxidants and antioxidants in favour of oxidants (oxidative stress) leads to the damage and may be highly involved in ocular aging processes. The anterior eye segment and mainly the cornea are directly exposed to noxae of external environment, such as air pollution, radiation, cigarette smoke, vapors or gases from household cleaning products, chemical burns from splashes of industrial chemicals, and danger from potential oxidative damage evoked by them. Oxidative stress may initiate or develop ocular injury resulting in decreased visual acuity or even vision loss. The role of oxidative stress in the pathogenesis of ocular diseases with particular attention to oxidative stress in the cornea and changes in corneal optical properties are discussed. Advances in the treatment of corneal oxidative injuries or diseases are shown. PMID:25861412

  10. Oxidative stress to the cornea, changes in corneal optical properties, and advances in treatment of corneal oxidative injuries.

    PubMed

    Cejka, Cestmir; Cejkova, Jitka

    2015-01-01

    Oxidative stress is involved in many ocular diseases and injuries. The imbalance between oxidants and antioxidants in favour of oxidants (oxidative stress) leads to the damage and may be highly involved in ocular aging processes. The anterior eye segment and mainly the cornea are directly exposed to noxae of external environment, such as air pollution, radiation, cigarette smoke, vapors or gases from household cleaning products, chemical burns from splashes of industrial chemicals, and danger from potential oxidative damage evoked by them. Oxidative stress may initiate or develop ocular injury resulting in decreased visual acuity or even vision loss. The role of oxidative stress in the pathogenesis of ocular diseases with particular attention to oxidative stress in the cornea and changes in corneal optical properties are discussed. Advances in the treatment of corneal oxidative injuries or diseases are shown. PMID:25861412

  11. Mesona Chinensis Benth extract prevents AGE formation and protein oxidation against fructose-induced protein glycation in vitro

    PubMed Central

    2014-01-01

    Background Mesona chinensis Benth (Chinese Mesona), an economically significant agricultural plant, is the most widely consumed as an herbal beverage in Southeast Asia and China. The objective of this study was to evaluate the inhibitory activity of Mesona chinensis (MC) extract on the formation of advanced glycation end products (AGEs) and protein oxidation in an in vitro model of fructose-mediated protein glycation. Methods The content of total polyphenolic compounds was measured by using Folin–Ciocalteu assay. Antiglycation activity was determined using the formation of AGE fluorescence intensity, Nϵ-(carboxymethyl)lysine (CML), the level of fructosamine, and the formation of amyloid cross β-structure. The protein oxidation was examined using the level of protein carbonyl content and thiol group. Results Our results revealed that the content of total polyphenolic compound in MC extract was 212.4 ± 5.6 mg gallic acid equivalents/g dried extract. MC extract (0.25-1.00 mg/mL) significantly inhibited the formation of fluorescence AGEs in fructose-glycated bovine serum albumin (BSA) during 4 weeks of study. Furthermore, MC extract also decreased the level of Nϵ-CML, fructosamine, and amyloid cross β-structure in fructose-glycated BSA. While the total thiol group was elevated and the protein carbonyl content was decreased in BSA incubated with fructose and MC extract. Conclusions The extract of MC inhibits fructose-mediated protein glycation and protein oxidation. This edible plant could be a natural rich source of antiglycation agent for preventing AGE-mediated diabetic complication. PMID:24708679

  12. Protein methionine oxidation augments reperfusion injury in acute ischemic stroke

    PubMed Central

    Gu, Sean X.; Blokhin, Ilya O.; Wilson, Katina M.; Dhanesha, Nirav; Doddapattar, Prakash; Grumbach, Isabella M.; Chauhan, Anil K.; Lentz, Steven R.

    2016-01-01

    Reperfusion injury can exacerbate tissue damage in ischemic stroke, but little is known about the mechanisms linking ROS to stroke severity. Here, we tested the hypothesis that protein methionine oxidation potentiates NF-κB activation and contributes to cerebral ischemia/reperfusion injury. We found that overexpression of methionine sulfoxide reductase A (MsrA), an antioxidant enzyme that reverses protein methionine oxidation, attenuated ROS-augmented NF-κB activation in endothelial cells, in part, by protecting against the oxidation of methionine residues in the regulatory domain of calcium/calmodulin-dependent protein kinase II (CaMKII). In a murine model, MsrA deficiency resulted in increased NF-κB activation and neutrophil infiltration, larger infarct volumes, and more severe neurological impairment after transient cerebral ischemia/reperfusion injury. This phenotype was prevented by inhibition of NF-κB or CaMKII. MsrA-deficient mice also exhibited enhanced leukocyte rolling and upregulation of E-selectin, an endothelial NF-κB–dependent adhesion molecule known to contribute to neurovascular inflammation in ischemic stroke. Finally, bone marrow transplantation experiments demonstrated that the neuroprotective effect was mediated by MsrA expressed in nonhematopoietic cells. These findings suggest that protein methionine oxidation in nonmyeloid cells is a key mechanism of postischemic oxidative injury mediated by NF-κB activation, leading to neutrophil recruitment and neurovascular inflammation in acute ischemic stroke. PMID:27294204

  13. Prediction of reversibly oxidized protein cysteine thiols using protein structure properties

    PubMed Central

    Sanchez, Ricardo; Riddle, Megan; Woo, Jongwook; Momand, Jamil

    2008-01-01

    Protein cysteine thiols can be divided into four groups based on their reactivities: those that form permanent structural disulfide bonds, those that coordinate with metals, those that remain in the reduced state, and those that are susceptible to reversible oxidation. Physicochemical parameters of oxidation-susceptible protein thiols were organized into a database named the Balanced Oxidation Susceptible Cysteine Thiol Database (BALOSCTdb). BALOSCTdb contains 161 cysteine thiols that undergo reversible oxidation and 161 cysteine thiols that are not susceptible to oxidation. Each cysteine was represented by a set of 12 parameters, one of which was a label (1/0) to indicate whether its thiol moiety is susceptible to oxidation. A computer program (the C4.5 decision tree classifier re-implemented as the J48 classifier) segregated cysteines into oxidation-susceptible and oxidation-non-susceptible classes. The classifier selected three parameters critical for prediction of thiol oxidation susceptibility: (1) distance to the nearest cysteine sulfur atom, (2) solvent accessibility, and (3) pKa. The classifier was optimized to correctly predict 136 of the 161 cysteine thiols susceptible to oxidation. Leave-one-out cross-validation analysis showed that the percent of correctly classified cysteines was 80.1% and that 16.1% of the oxidation-susceptible cysteine thiols were incorrectly classified. The algorithm developed from these parameters, named the Cysteine Oxidation Prediction Algorithm (COPA), is presented here. COPA prediction of oxidation-susceptible sites can be utilized to locate protein cysteines susceptible to redox-mediated regulation and identify possible enzyme catalytic sites with reactive cysteine thiols. PMID:18287280

  14. Applications of advanced oxidation processes: present and future.

    PubMed

    Suty, H; De Traversay, C; Cost, M

    2004-01-01

    The use of advanced oxidation processes (AOPs) to remove pollutants in various water treatment applications has been the subject of study for around 30 years. Most of the available processes (Fenton reagent, O3 under basic conditions, O3/H2O2, O3/UV, O3/solid catalyst, H2O2/M(n+), H2O2/UV, photo-assisted Fenton, H2O2/solid catalyst, H2O2/NaClO, TiO2/UV etc.) have been investigated in depth and a considerable body of knowledge has been built up about the reactivity of many pollutants. Various industrial applications have been developed, including ones for ground remediation (TCE, PCE), the removal of pesticides from drinking water, the removal of formaldehyde and phenol from industrial waste water and a reduction in COD from industrial waste water. The development of such AOP applications has been stimulated by increasingly stringent regulations, the pollution of water resources through agricultural and industrial activities and the requirement that industry meet effluent discharge standards. Nevertheless, it is difficult to obtain an accurate picture of the use of AOPs and its exact position in the range of water treatment processes has not been determined to date. The purpose of this overview is to discuss those processes and provide an indication of future trends. PMID:15077976

  15. Ratiometric Raman Spectroscopy for Quantification of Protein Oxidative Damage

    PubMed Central

    Jiang, Dongping; Yanney, Michael; Zou, Sige; Sygula, Andrzej

    2009-01-01

    A novel ratiometric Raman spectroscopic (RMRS) method has been developed for quantitative determination of protein carbonyl levels. Oxidized bovine serum albumin (BSA) and oxidized lysozyme were used as model proteins to demonstrate this method. The technique involves conjugation of protein carbonyls with dinitrophenyl hydrazine (DNPH), followed by drop coating deposition Raman spectral acquisition (DCDR). The RMRS method is easy to implement as it requires only one conjugation reaction, a single spectral acquisition, and does not require sample calibration. Characteristic peaks from both protein and DNPH moieties are obtained in a single spectral acquisition, allowing the protein carbonyl level to be calculated from the peak intensity ratio. Detection sensitivity for the RMRS method is ~0.33 pmol carbonyl/measurement. Fluorescence and/or immunoassay based techniques only detect a signal from the labeling molecule and thus yield no structural or quantitative information for the modified protein while the RMRS technique provides for protein identification and protein carbonyl quantification in a single experiment. PMID:19457432

  16. A comparison between conductive-diamond electrochemical oxidation and other advanced oxidation processes for the treatment of synthetic melanoidins.

    PubMed

    Cañizares, P; Hernández-Ortega, M; Rodrigo, M A; Barrera-Díaz, C E; Roa-Morales, G; Sáez, C

    2009-05-15

    In this study, three technologies classified as Advanced Oxidation Processes (Conductive-Diamond Electrochemical Oxidation (CDEO), ozonation and Fenton oxidation) have been compared to treat wastes produced in fermentation processes, and characterized by a significant color and a high organic load. Results of CDEO seem to strongly depend on the addition of an electrolyte salt, not only to decrease the energy cost but also to improve efficiency. The addition of sodium chloride as supporting electrolyte improves the removal percentages of organic load, indicating the important role of mediated oxidation processes carried out by the electrogenerated oxidants (hypochlorite). Fenton oxidation and ozonation seem to be less efficient, and mainly Fenton oxidation favors the accumulation of refractory compounds. The differences observed can be explained in terms of the contribution of hydroxyl radicals and other specific oxidation mechanisms involved in each technology. PMID:18789836

  17. Myeloperoxidase-derived oxidants rapidly oxidize and disrupt zinc-cysteine/histidine clusters in proteins.

    PubMed

    Cook, Naomi L; Pattison, David I; Davies, Michael J

    2012-12-01

    Zinc is an abundant cellular transition metal ion, which binds avidly to protein cysteine (Cys) and histidine (His) residues to form zinc-Cys/His clusters; these play a key role in the function of many proteins (e.g., DNA binding and repair enzymes, transcription factors, nitric oxide synthase). Leukocyte-derived myeloperoxidase generates powerful oxidants including hypochlorous (HOCl), hypobromous (HOBr), and hypothiocyanous (HOSCN) acids from H(2)O(2) and (pseudo)halide ions. Excessive or misplaced formation of these species is associated with cellular dysfunction, apoptosis and necrosis, and multiple inflammatory diseases. HOCl and HOBr react rapidly with sulfur-containing compounds, and HOSCN reacts specifically with thiols. Consequently, we hypothesized that zinc-Cys/His clusters would be targets for these oxidants, and the activity of such enzymes would be perturbed. This hypothesis has been tested using yeast alcohol dehydrogenase (YADH), which contains a well-characterized Zn(1)Cys(2)His(1) cluster. Incubation of YADH with pathologically relevant concentrations of HOSCN, HOCl, and HOBr resulted in rapid oxidation of the protein (rate constants, determined by competition kinetics, for reaction of HOCl and HOSCN with YADH being (3.3±0.9)×10(8) and (2.9±0.4)×10(4) M(-1) s(-1) per YADH monomer, respectively), loss of enzyme activity, Zn(2+) release, changes in protein structure (particularly formation of disulfide cross-links), and oxidation of Cys residues. The loss of enzyme activity correlated with Zn(2+) release, loss of thiols, and changes in protein structure. We conclude that exposure of zinc-Cys/His clusters to inflammatory oxidants can result in impaired protein activity, thiol oxidation, and Zn(2+) release. These reactions may contribute to inflammation-induced tissue damage. PMID:23032100

  18. Linking protein oxidation to environmental pollutants: redox proteomic approaches.

    PubMed

    Braconi, Daniela; Bernardini, Giulia; Santucci, Annalisa

    2011-10-19

    Environmental pollutants, such as compounds used in agriculture or deriving from vehicles, industries and human activities, can represent major concern for human health since they are considered to contribute significantly to many diseased states with major public health significance. Besides considerable epidemiological evidence linking environmental pollutants with adverse health effects, little information is provided on the effects of these compounds at the cellular and molecular level. Though oxidative stress is generally acknowledged as one of the most important mechanisms of action for pollutant-induced toxicity, redox proteomics, the elective tool to identify post-translationally oxidized proteins, is still in its very infancy in this field of investigation. This review will provide the readers with an outline of the use of redox proteomics in evaluating pollutant-induced oxidative damage to proteins in various biological systems. Future potential applications of redox proteomic approaches from an environmental point of view will be discussed as well. PMID:21767673

  19. Conservation of Oxidative Protein Stabilization in an Insect Homologue of Parkinsonism-Associated Protein DJ-1

    SciTech Connect

    Lin, Jiusheng; Prahlad, Janani; Wilson, Mark A.

    2012-08-21

    DJ-1 is a conserved, disease-associated protein that protects against oxidative stress and mitochondrial damage in multiple organisms. Human DJ-1 contains a functionally essential cysteine residue (Cys106) whose oxidation is important for regulating protein function by an unknown mechanism. This residue is well-conserved in other DJ-1 homologues, including two (DJ-1{alpha} and DJ-1{beta}) in Drosophila melanogaster. Because D. melanogaster is a powerful model system for studying DJ-1 function, we have determined the crystal structure and impact of cysteine oxidation on Drosophila DJ-1{beta}. The structure of D. melanogaster DJ-1{beta} is similar to that of human DJ-1, although two important residues in the human protein, Met26 and His126, are not conserved in DJ-1{beta}. His126 in human DJ-1 is substituted with a tyrosine in DJ-1{beta}, and this residue is not able to compose a putative catalytic dyad with Cys106 that was proposed to be important in the human protein. The reactive cysteine in DJ-1 is oxidized readily to the cysteine-sulfinic acid in both flies and humans, and this may regulate the cytoprotective function of the protein. We show that the oxidation of this conserved cysteine residue to its sulfinate form (Cys-SO{sub 2{sup -}}) results in considerable thermal stabilization of both Drosophila DJ-1{beta} and human DJ-1. Therefore, protein stabilization is one potential mechanism by which cysteine oxidation may regulate DJ-1 function in vivo. More generally, most close DJ-1 homologues are likely stabilized by cysteine-sulfinic acid formation but destabilized by further oxidation, suggesting that they are biphasically regulated by oxidative modification.

  20. Protein Oxidation Implicated as the Primary Determinant of Bacterial Radioresistance

    PubMed Central

    Daly, Michael J; Gaidamakova, Elena K; Matrosova, Vera Y; Vasilenko, Alexander; Zhai, Min; Leapman, Richard D; Lai, Barry; Ravel, Bruce; Li, Shu-Mei W; Kemner, Kenneth M; Fredrickson, James K

    2007-01-01

    In the hierarchy of cellular targets damaged by ionizing radiation (IR), classical models of radiation toxicity place DNA at the top. Yet, many prokaryotes are killed by doses of IR that cause little DNA damage. Here we have probed the nature of Mn-facilitated IR resistance in Deinococcus radiodurans, which together with other extremely IR-resistant bacteria have high intracellular Mn/Fe concentration ratios compared to IR-sensitive bacteria. For in vitro and in vivo irradiation, we demonstrate a mechanistic link between Mn(II) ions and protection of proteins from oxidative modifications that introduce carbonyl groups. Conditions that inhibited Mn accumulation or Mn redox cycling rendered D. radiodurans radiation sensitive and highly susceptible to protein oxidation. X-ray fluorescence microprobe analysis showed that Mn is globally distributed in D. radiodurans, but Fe is sequestered in a region between dividing cells. For a group of phylogenetically diverse IR-resistant and IR-sensitive wild-type bacteria, our findings support the idea that the degree of resistance is determined by the level of oxidative protein damage caused during irradiation. We present the case that protein, rather than DNA, is the principal target of the biological action of IR in sensitive bacteria, and extreme resistance in Mn-accumulating bacteria is based on protein protection. PMID:17373858

  1. Protein oxidation implicated as the primary determinant of bacterial radioresistance.

    PubMed

    Daly, Michael J; Gaidamakova, Elena K; Matrosova, Vera Y; Vasilenko, Alexander; Zhai, Min; Leapman, Richard D; Lai, Barry; Ravel, Bruce; Li, Shu-Mei W; Kemner, Kenneth M; Fredrickson, James K

    2007-04-01

    In the hierarchy of cellular targets damaged by ionizing radiation (IR), classical models of radiation toxicity place DNA at the top. Yet, many prokaryotes are killed by doses of IR that cause little DNA damage. Here we have probed the nature of Mn-facilitated IR resistance in Deinococcus radiodurans, which together with other extremely IR-resistant bacteria have high intracellular Mn/Fe concentration ratios compared to IR-sensitive bacteria. For in vitro and in vivo irradiation, we demonstrate a mechanistic link between Mn(II) ions and protection of proteins from oxidative modifications that introduce carbonyl groups. Conditions that inhibited Mn accumulation or Mn redox cycling rendered D. radiodurans radiation sensitive and highly susceptible to protein oxidation. X-ray fluorescence microprobe analysis showed that Mn is globally distributed in D. radiodurans, but Fe is sequestered in a region between dividing cells. For a group of phylogenetically diverse IR-resistant and IR-sensitive wild-type bacteria, our findings support the idea that the degree of resistance is determined by the level of oxidative protein damage caused during irradiation. We present the case that protein, rather than DNA, is the principal target of the biological action of IR in sensitive bacteria, and extreme resistance in Mn-accumulating bacteria is based on protein protection. PMID:17373858

  2. Protein Oxidation Implicated as the Primary Determinant of Bacterial Radioresistance

    SciTech Connect

    Daly, Michael J.; Gaidamakova, E.; Matrosova, V.; Vasilenko, A.; Zhai, M.; leapman, Richard D.; Lai, Barry; Ravel, Bruce; Li, Shu-Mei W.; Kemner, Kenneth M.; Fredrickson, Jim K.

    2007-04-02

    In the hierarchy of cellular targets damaged by ionizing radiation (IR), classical models of radiation toxicity place DNA at the top. Yet, many prokaryotes are killed by doses of IR that cause little DNA damage. Here we have probed the nature of manganese-facilitated IR resistance in Deinococcus radiodurans, which together with other extremely IR resistant bacteria have high intracellular Mn/Fe concentration ratios compared to IR sensitive bacteria. For in vitro and in vivo irradiation, we demonstrate a mechanistic link between Mn(II) ions and protection of proteins from oxidative modifications which introduce carbonyl groups. Conditions which inhibited Mn-accumulation or Mn redox-cycling rendered D. radiodurans radiation sensitive and highly susceptible to protein oxidation. X-ray fluorescence (XRF) microprobe analysis showed that Mn is globally distributed in D. radiodurans, but Fe is sequestered in a region between dividing cells. For a group of phylogenetically diverse IR resistant and sensitive bacteria, our findings support that the degree of resistance is determined by the level of oxidative protein damage caused during irradiation. We present the case that protein, rather than DNA, is the principal target of the biological action of IR in sensitive bacteria, and extreme resistance in Mn-accumulating bacteria is based on protein protection.

  3. Temperature of frozen storage affects the nature and consequences of protein oxidation in beef patties.

    PubMed

    Utrera, Mariana; Morcuende, David; Estévez, Mario

    2014-03-01

    The effect of three frozen storage temperatures (-8, -18 and -80 °C) on protein oxidation in beef patties was studied through the analysis of novel oxidation markers. Additionally, the connection between lipid and protein oxidation and the impact of the latter on particular quality traits (water holding capacity, color and texture) of subsequently processed beef patties (cooking/cold-stored) were investigated. Protein oxidation was measured as the loss of tryptophan fluorescence and formation of diverse lysine oxidation products (α-aminoadipic semialdehyde, α-aminoadipic acid and Schiff bases). Lipid oxidation was assessed by levels of thiobarbituric acid reactive substances and hexanal. A significant effect of storage temperature on protein oxidation was detected. Frozen storage increased the susceptibility of meat proteins to undergo further oxidation during processing. Timely interactions were found between lipid and protein oxidation. Plausible mechanisms by which oxidative damage to proteins may have an impact in particular quality traits are thoroughly discussed. PMID:24334047

  4. Methods to monitor classical protein-tyrosine phosphatase oxidation

    PubMed Central

    Karisch, Robert; Neel, Benjamin G.

    2012-01-01

    SUMMARY Reactive oxygen species (ROS), particularly H2O2, act as intracellular second messengers in many signaling pathways. Protein-tyrosine phosphatases (PTPs) are now believed to be important targets of ROS. PTPs contain a conserved catalytic cysteine with an unusually low pKa. This property allows PTPs to execute nucleophilic attack on substrate phosphotyrosyl residues, but also renders them highly susceptible to oxidation. Reversible oxidation, which inactivates PTPs, is emerging as an important cellular regulatory mechanism and might contribute to human diseases, including cancer. Given their potential toxicity, it seems likely that ROS generation is highly controlled within cells to restrict oxidation to those PTPs that must be inactivated for signaling to proceed. Thus, identifying ROS-inactivated PTPs could be tantamount to finding the PTP(s) that critically regulate a specific signaling pathway. This article provides an overview of the methods currently available to identify and quantify PTP oxidation and outlines future challenges in redox signaling. PMID:22577968

  5. A solar-driven UV/Chlorine advanced oxidation process.

    PubMed

    Chan, Po Yee; Gamal El-Din, Mohamed; Bolton, James R

    2012-11-01

    An overlap of the absorption spectrum of the hypochlorite ion (OCl(-)) and the ultraviolet (UV) end of the solar emission spectrum implies that solar photons can probably initiate the UV/chlorine advanced oxidation process (AOP). The application of this solar process to water and wastewater treatment has been investigated in this study. At the bench-scale, the OCl(-) photolysis quantum yield at 303 nm (representative of the lower end of the solar UV region) and at concentrations from 0 to 4.23 mM was 0.87 ± 0.01. Also the hydroxyl radical yield factor (for an OCl(-) concentration of 1.13 mM) was 0.70 ± 0.02. Application of this process, at the bench-scale and under actual sunlight, led to methylene blue (MB) photobleaching and cyclohexanoic acid (CHA) photodegradation. For MB photobleaching, the OCl(-) concentration was the key factor causing an increase in the pseudo first-order rate constants. The MB photobleaching quantum yield was affected by the MB concentration, but not much by the OCl(-) concentration. For CHA photodegradation, an optimal OCl(-) concentration of 1.55 mM was obtained for a 0.23 mM CHA concentration, and a scavenger effect was observed when higher OCl(-) concentrations were applied. Quantum yields of 0.09 ± 0.01 and 0.89 ± 0.06 were found for CHA photodegradation and OCl(-) photolysis, respectively. In addition, based on the Air Mass 1.5 reference solar spectrum and experimental quantum yields, a theoretical calculation method was developed to estimate the initial rate for photoreactions under sunlight. The theoretical initial rates agreed well with the experimental rates for both MB photobleaching and CHA photodegradation. PMID:22939221

  6. Modular Advanced Oxidation Process Enabled by Cathodic Hydrogen Peroxide Production

    PubMed Central

    2015-01-01

    Hydrogen peroxide (H2O2) is frequently used in combination with ultraviolet (UV) light to treat trace organic contaminants in advanced oxidation processes (AOPs). In small-scale applications, such as wellhead and point-of-entry water treatment systems, the need to maintain a stock solution of concentrated H2O2 increases the operational cost and complicates the operation of AOPs. To avoid the need for replenishing a stock solution of H2O2, a gas diffusion electrode was used to generate low concentrations of H2O2 directly in the water prior to its exposure to UV light. Following the AOP, the solution was passed through an anodic chamber to lower the solution pH and remove the residual H2O2. The effectiveness of the technology was evaluated using a suite of trace contaminants that spanned a range of reactivity with UV light and hydroxyl radical (HO•) in three different types of source waters (i.e., simulated groundwater, simulated surface water, and municipal wastewater effluent) as well as a sodium chloride solution. Irrespective of the source water, the system produced enough H2O2 to treat up to 120 L water d–1. The extent of transformation of trace organic contaminants was affected by the current density and the concentrations of HO• scavengers in the source water. The electrical energy per order (EEO) ranged from 1 to 3 kWh m–3, with the UV lamp accounting for most of the energy consumption. The gas diffusion electrode exhibited high efficiency for H2O2 production over extended periods and did not show a diminution in performance in any of the matrices. PMID:26039560

  7. Modular advanced oxidation process enabled by cathodic hydrogen peroxide production.

    PubMed

    Barazesh, James M; Hennebel, Tom; Jasper, Justin T; Sedlak, David L

    2015-06-16

    Hydrogen peroxide (H2O2) is frequently used in combination with ultraviolet (UV) light to treat trace organic contaminants in advanced oxidation processes (AOPs). In small-scale applications, such as wellhead and point-of-entry water treatment systems, the need to maintain a stock solution of concentrated H2O2 increases the operational cost and complicates the operation of AOPs. To avoid the need for replenishing a stock solution of H2O2, a gas diffusion electrode was used to generate low concentrations of H2O2 directly in the water prior to its exposure to UV light. Following the AOP, the solution was passed through an anodic chamber to lower the solution pH and remove the residual H2O2. The effectiveness of the technology was evaluated using a suite of trace contaminants that spanned a range of reactivity with UV light and hydroxyl radical (HO(•)) in three different types of source waters (i.e., simulated groundwater, simulated surface water, and municipal wastewater effluent) as well as a sodium chloride solution. Irrespective of the source water, the system produced enough H2O2 to treat up to 120 L water d(-1). The extent of transformation of trace organic contaminants was affected by the current density and the concentrations of HO(•) scavengers in the source water. The electrical energy per order (EEO) ranged from 1 to 3 kWh m(-3), with the UV lamp accounting for most of the energy consumption. The gas diffusion electrode exhibited high efficiency for H2O2 production over extended periods and did not show a diminution in performance in any of the matrices. PMID:26039560

  8. Advances in identification and validation of protein targets of natural products without chemical modification.

    PubMed

    Chang, J; Kim, Y; Kwon, H J

    2016-05-01

    Covering: up to February 2016Identification of the target proteins of natural products is pivotal to understanding the mechanisms of action to develop natural products for use as molecular probes and potential therapeutic drugs. Affinity chromatography of immobilized natural products has been conventionally used to identify target proteins, and has yielded good results. However, this method has limitations, in that labeling or tagging for immobilization and affinity purification often result in reduced or altered activity of the natural product. New strategies have recently been developed and applied to identify the target proteins of natural products and synthetic small molecules without chemical modification of the natural product. These direct and indirect methods for target identification of label-free natural products include drug affinity responsive target stability (DARTS), stability of proteins from rates of oxidation (SPROX), cellular thermal shift assay (CETSA), thermal proteome profiling (TPP), and bioinformatics-based analysis of connectivity. This review focuses on and reports case studies of the latest advances in target protein identification methods for label-free natural products. The integration of newly developed technologies will provide new insights and highlight the value of natural products for use as biological probes and new drug candidates. PMID:26964663

  9. Development of a microsecond X-ray protein footprinting facility at the Advanced Light Source

    PubMed Central

    Gupta, Sayan; Celestre, Richard; Petzold, Christopher J.; Chance, Mark R.; Ralston, Corie

    2014-01-01

    X-ray footprinting (XF) is an important structural biology tool used to determine macromolecular conformations and dynamics of both nucleic acids and proteins in solution on a wide range of timescales. With the impending shut-down of the National Synchrotron Light Source, it is ever more important that this tool continues to be developed at other synchrotron facilities to accommodate XF users. Toward this end, a collaborative XF program has been initiated at the Advanced Light Source using the white-light bending-magnet beamlines 5.3.1 and 3.2.1. Accessibility of the microsecond time regime for protein footprinting is demonstrated at beamline 5.3.1 using the high flux density provided by a focusing mirror in combination with a micro-capillary flow cell. It is further reported that, by saturating samples with nitrous oxide, the radiolytic labeling efficiency is increased and the imprints of bound versus bulk water can be distinguished. These results both demonstrate the suitability of the Advanced Light Source as a second home for the XF experiment, and pave the way for obtaining high-quality structural data on complex protein samples and dynamics information on the microsecond timescale. PMID:24971962

  10. [Recent advances in the techniques of protein-protein interaction study].

    PubMed

    Wang, Ming-Qiang; Wu, Jin-Xia; Zhang, Yu-Hong; Han, Ning; Bian, Hong-Wu; Zhu, Mu-Yuan

    2013-11-01

    Protein-protein interactions play key roles in the development of organisms and the response to biotic and abiotic stresses. Several wet-lab methods have been developed to study this challenging area,including yeast two-hybrid system, tandem affinity purification, Co-immunoprecipitation, GST Pull-down, bimolecular fluorescence complementation, fluorescence resonance energy transfer and surface plasmon resonance analysis. In this review, we discuss theoretical principles and relative advantages and disvantages of these techniques,with an emphasis on recent advances to compensate for limitations. PMID:24579310

  11. Biologically relevant oxidants cause bound proteins to readily oxidatively cross-link at Guanine.

    PubMed

    Solivio, Morwena J; Nemera, Dessalegn B; Sallans, Larry; Merino, Edward J

    2012-02-20

    Oxidative DNA-protein cross-links have received less attention than other types of DNA damage and remain as one of the least understood types of oxidative lesion. A model system using ribonuclease A and a 27-nucleotide DNA was used to determine the propensity of oxidative cross-linking to occur in the presence of oxidants. Cross-link formation was examined using four different oxidation systems that generate singlet oxygen, superoxide, and metal-based Fenton reactions. It is shown that oxidative cross-linking occurs in yields ranging from 14% to a maximal yield of 61% in all oxidative systems when equivalent concentrations of DNA and protein are present. Because singlet oxygen is the most efficient oxidation system in generating DNA-protein cross-links, it was chosen for further analyses. Cross-linking occurred with single-stranded DNA binding protein and not with bovine serum albumin. Addition of salt lowered nonspecific binding affinity and lowered cross-link yield by up to 59%. The yield of cross-linking increased with increased ratios of protein compared with DNA. Cross-linking was highly dependent on the number of guanines in a DNA sequence. Loss of guanine content on the 27-nucleotide DNA led to nearly complete loss in cross-linking, while primer extension studies showed cross-links to predominantly occur at guanine base on a 100-nucleotide DNA. The chemical species generated were examined using two peptides derived from the ribonuclease A sequence, N-acetyl-AAAKF and N-acetyl-AYKTT, which were cross-linked to 2'-deoxyguanosine. The cross-link products were spiroiminodihydantoin, guanidinohydantoin, and tyrosyl-based adducts. Formation of tyrosine-based adducts may be competitive with the more well-studied lysine-based cross-links. We conclude that oxidative cross-links may be present at high levels in cells since the propensity to oxidatively cross-link is high and so much of the genomic DNA is coated with protein. PMID:22216745

  12. Molecular interactions of graphene oxide with human blood plasma proteins

    NASA Astrophysics Data System (ADS)

    Kenry, Affa Affb Affc; Loh, Kian Ping; Lim, Chwee Teck

    2016-04-01

    We investigate the molecular interactions between graphene oxide (GO) and human blood plasma proteins. To gain an insight into the bio-physico-chemical activity of GO in biological and biomedical applications, we performed a series of biophysical assays to quantify the molecular interactions between GO with different lateral size distributions and the three essential human blood plasma proteins. We elucidate the various aspects of the GO-protein interactions, particularly, the adsorption, binding kinetics and equilibrium, and conformational stability, through determination of quantitative parameters, such as GO-protein association constants, binding cooperativity, and the binding-driven protein structural changes. We demonstrate that the molecular interactions between GO and plasma proteins are significantly dependent on the lateral size distribution and mean lateral sizes of the GO nanosheets and their subtle variations may markedly influence the GO-protein interactions. Consequently, we propose the existence of size-dependent molecular interactions between GO nanosheets and plasma proteins, and importantly, the presence of specific critical mean lateral sizes of GO nanosheets in achieving very high association and fluorescence quenching efficiency of the plasma proteins. We anticipate that this work will provide a basis for the design of graphene-based and other related nanomaterials for a plethora of biological and biomedical applications.

  13. Integration of advanced oxidation technologies and biological processes: recent developments, trends, and advances.

    PubMed

    Tabrizi, Gelareh Bankian; Mehrvar, Mehrab

    2004-01-01

    The greatest challenge of today's wastewater treatment technology is to optimize the use of biological and chemical wastewater treatment processes. The choice of the process and/or integration of the processes depend strongly on the wastewater characteristics, concentrations, and the desired efficiencies. It has been observed by many investigators that the coupling of a bioreactor and advanced oxidation processes (AOPs) could reduce the final concentrations of the effluent to the desired values. However, optimizing the total cost of the treatment is a challenge, as AOPs are much more expensive than biological processes alone. Therefore, an appropriate design should not only consider the ability of this coupling to reduce the concentration of organic pollutants, but also try to obtain the desired results in a cost effective process. To consider the total cost of the treatment, the residence time in biological and photochemical reactors, the kinetic rates, and the capital and operating costs of the reactors play significant roles. In this study, recent developments and trends (1996-2003) on the integration of photochemical and biological processes for the degradation of problematic pollutants in wastewater have been reviewed. The conditions to get the optimum results from this integration have also been considered. In most of the studies, it has been shown that the integrated processes were more efficient than individual processes. However, slight changes in the configuration of the reactors, temperature, pH, treatment time, concentration of the oxidants, and microorganism's colonies could lead to a great deviation in results. It has also been demonstrated that the treatment cost in both reactors is a function of time, which changes by the flow rate. The minimum cost in the coupling of the processes cannot be achieved unless considering the best treatment time in chemical and biological reactors individually. PMID:15533022

  14. Cell signaling through protein kinase C oxidation and activation.

    PubMed

    Cosentino-Gomes, Daniela; Rocco-Machado, Nathália; Meyer-Fernandes, José Roberto

    2012-01-01

    Due to the growing importance of cellular signaling mediated by reactive oxygen species (ROS), proteins that are reversibly modulated by these reactant molecules are of high interest. In this context, protein kinases and phosphatases, which act coordinately in the regulation of signal transduction through the phosphorylation and dephosphorylation of target proteins, have been described to be key elements in ROS-mediated signaling events. The major mechanism by which these proteins may be modified by oxidation involves the presence of key redox-sensitive cysteine residues. Protein kinase C (PKC) is involved in a variety of cellular signaling pathways. These proteins have been shown to contain a unique structural feature that is susceptible to oxidative modification. A large number of scientific studies have highlighted the importance of ROS as a second messenger in numerous cellular processes, including cell proliferation, gene expression, adhesion, differentiation, senescence, and apoptosis. In this context, the goal of this review is to discuss the mechanisms by which PKCs are modulated by ROS and how these processes are involved in the cellular response. PMID:23109817

  15. Remediation of a winery wastewater combining aerobic biological oxidation and electrochemical advanced oxidation processes.

    PubMed

    Moreira, Francisca C; Boaventura, Rui A R; Brillas, Enric; Vilar, Vítor J P

    2015-05-15

    Apart from a high biodegradable fraction consisting of organic acids, sugars and alcohols, winery wastewaters exhibit a recalcitrant fraction containing high-molecular-weight compounds as polyphenols, tannins and lignins. In this context, a winery wastewater was firstly subjected to a biological oxidation to mineralize the biodegradable fraction and afterwards an electrochemical advanced oxidation process (EAOP) was applied in order to mineralize the refractory molecules or transform them into simpler ones that can be further biodegraded. The biological oxidation led to above 97% removals of dissolved organic carbon (DOC), chemical oxygen demand (COD) and 5-day biochemical oxygen demand (BOD5), but was inefficient on the degradation of a bioresistant fraction corresponding to 130 mg L(-1) of DOC, 380 mg O2 L(-1) of COD and 8.2 mg caffeic acid equivalent L(-1) of total dissolved polyphenols. Various EAOPs such as anodic oxidation with electrogenerated H2O2 (AO-H2O2), electro-Fenton (EF), UVA photoelectro-Fenton (PEF) and solar PEF (SPEF) were then applied to the recalcitrant effluent fraction using a 2.2 L lab-scale flow plant containing an electrochemical cell equipped with a boron-doped diamond (BDD) anode and a carbon-PTFE air-diffusion cathode and coupled to a photoreactor with compound parabolic collectors (CPCs). The influence of initial Fe(2+) concentration and current density on the PEF process was evaluated. The relative oxidative ability of EAOPs increased in the order AO-H2O2 < EF < PEF ≤ SPEF. The SPEF process using an initial Fe(2+) concentration of 35 mg L(-1), current density of 25 mA cm(-2), pH of 2.8 and 25 °C reached removals of 86% on DOC and 68% on COD after 240 min, regarding the biologically treated effluent, along with energy consumptions of 45 kWh (kg DOC)(-1) and 5.1 kWh m(-3). After this coupled treatment, color, odor, COD, BOD5, NH4(+), NO3(-) and SO4(2-) parameters complied with the legislation targets and, in addition, a total

  16. Polysulfides Link H2S to Protein Thiol Oxidation

    PubMed Central

    Greiner, Romy; Pálinkás, Zoltán; Bäsell, Katrin; Becher, Dörte; Antelmann, Haike; Nagy, Péter

    2013-01-01

    Abstract Aims: Hydrogen sulfide (H2S) is suggested to act as a gaseous signaling molecule in a variety of physiological processes. Its molecular mechanism of action was proposed to involve protein S-sulfhydration, that is, conversion of cysteinyl thiolates (Cys-S−) to persulfides (Cys-S-S−). A central and unresolved question is how H2S—that is, a molecule with sulfur in its lowest possible oxidation state (−2)—can lead to oxidative thiol modifications. Results: Using the lipid phosphatase PTEN as a model protein, we find that the “H2S donor” sodium hydrosulfide (NaHS) leads to very rapid reversible oxidation of the enzyme in vitro. We identify polysulfides formed in NaHS solutions as the oxidizing species, and present evidence that sulfane sulfur is added to the active site cysteine. Polysulfide-mediated oxidation of PTEN was induced by all “H2S donors” tested, including sodium sulfide (Na2S), gaseous H2S, and morpholin-4-ium 4-methoxyphenyl(morpholino) phosphinodithioate (GYY4137). Moreover, we show that polysulfides formed in H2S solutions readily modify PTEN inside intact cells. Innovation: Our results shed light on the previously unresolved question of how H2S leads to protein thiol oxidation, and suggest that polysulfides formed in solutions of H2S mediate this process. Conclusion: This study suggests that the effects that have been attributed to H2S in previous reports may in fact have been mediated by polysulfides. It also supports the notion that sulfane sulfur rather than sulfide is the actual in vivo agent of H2S signaling. Antioxid. Redox Signal. 19, 1749–1765. PMID:23646934

  17. Oxidative Modification of Proteins: An Emerging Mechanism of Cell Signaling

    PubMed Central

    Wall, Stephanie B.; Oh, Joo-Yeun; Diers, Anne R.; Landar, Aimee

    2012-01-01

    There are a wide variety of reactive species which can affect cell function, including reactive oxygen, nitrogen, and lipid species. Some are formed endogenously through enzymatic or non-enzymatic pathways, and others are introduced through diet or environmental exposure. Many of these reactive species can interact with biomolecules and can result in oxidative post-translational modification of proteins. It is well documented that some oxidative modifications cause macromolecular damage and cell death. However, a growing body of evidence suggests that certain classes of reactive species initiate cell signaling by reacting with specific side chains of peptide residues without causing cell death. This process is generally termed “redox signaling,” and its role in physiological and pathological processes is a subject of active investigation. This review will give an overview of oxidative protein modification as a mechanism of redox signaling, including types of reactive species and how they modify proteins, examples of modified proteins, and a discussion about the current concepts in this area. PMID:23049513

  18. Bioanalytical advances in assays for C-reactive protein.

    PubMed

    Vashist, Sandeep Kumar; Venkatesh, A G; Marion Schneider, E; Beaudoin, Christopher; Luppa, Peter B; Luong, John H T

    2016-01-01

    This review presents advances in assays for human C-reactive protein (CRP), the most important biomarker of infection and inflammation for a plethora of diseases and pathophysiological conditions. Routine assays in clinical settings are based on analyzers, enzyme-linked immunosorbent assays and lateral flow assays. However, assays encompassing novel sensing schemes, improved chemistry, signal enhancement, lab-on-a-chip, microfluidics and smartphone detection, have emerged in recent years. The incorporation of immune-transducing chips or sensing interfaces with nanomaterials enables multiplexing analysis of CRP with co-existing biomarkers. However, there are still considerable challenges in the development of rapid diagnostics for both pentameric and monomeric CRP forms. PMID:26717866

  19. Red Fluorescent Proteins: Advanced Imaging Applications and Future Design

    PubMed Central

    Shcherbakova, Daria M.; Subach, Oksana M.; Verkhusha, Vladislav V.

    2015-01-01

    In the past few years a large series of the advanced red-shifted fluorescent proteins (RFPs) has been developed. These enhanced RFPs provide new possibilities to study biological processes at the levels ranging from single molecules to whole organisms. Herein the relationship between the properties of the RFPs of different phenotypes and their applications to various imaging techniques are described. Existing and emerging imaging approaches are discussed for conventional RFPs, far-red FPs, RFPs with a large Stokes shift, fluorescent timers, irreversibly photoactivatable and reversibly photo-switchable RFPs. Advantages and limitations of specific RFPs for each technique are presented. Recent progress in understanding the chemical transformations of red chromophores allows the future RFP phenotypes and their respective novel imaging applications to be foreseen. PMID:22851529

  20. Protein oxidation and proteolysis during storage and in vitro digestion of pork and beef patties.

    PubMed

    Rysman, Tine; Van Hecke, Thomas; Van Poucke, Christof; De Smet, Stefaan; Van Royen, Geert

    2016-10-15

    The effect of protein oxidation on proteolysis during meat digestion was investigated following storage and subsequent in vitro digestion of beef and pork patties. Protein oxidation was evaluated as thiol oxidation, total carbonylation, and specific carbonylation (α-amino adipic and γ-glutamic semialdehyde). Furthermore, 4-hydroxyphenylalanine, a hydroxylation product of phenylalanine, was identified and quantified as a new protein oxidation marker. After 7days of chilled illuminated storage (4°C), significant oxidative modifications were quantified and the oxidative degradation was continued during in vitro digestion. The observed effects were more abundant in beef patties. Protein oxidation before digestion resulted in impaired proteolysis during digestion. PMID:27173550

  1. Prospects and advancements in C-reactive protein detection

    PubMed Central

    Chandra, Pranjal; Suman, Pankaj; Airon, Himangi; Mukherjee, Monalisa; Kumar, Prabhanshu

    2014-01-01

    C-reactive protein (CRP) is one of the earliest proteins that appear in the blood circulation in most systemic inflammatory conditions and this is the reason for its significance, even after identification of many organ specific inflammatory markers which appear relatively late during the course of disease. Earlier methods of CRP detection were based on the classical methods of antigen-antibody interaction through precipitation and agglutination reactions. Later on, CRP based enzymatic assays came into the picture which were further modified by integration of an antigen-antibody detection system with surface plasma spectroscopy. Then came the time for the development of electrochemical biosensors where nanomaterials were used to make a highly sensitive and portable detection system based on silicon nanowire, metal-oxide-semiconductor field-effect transistor/bipolar junction transistor, ZnS nanoparticle, aptamer, field emission transmitter, vertical flow immunoassay etc. This editorial attempts to summarize developments in the field of CRP detection, with a special emphasis on biosensor technology. This would help in translating the latest development in CRP detection in the clinical diagnosis of inflammatory conditions at an early onset of the diseases. PMID:25237625

  2. Prospects and advancements in C-reactive protein detection.

    PubMed

    Chandra, Pranjal; Suman, Pankaj; Airon, Himangi; Mukherjee, Monalisa; Kumar, Prabhanshu

    2014-03-26

    C-reactive protein (CRP) is one of the earliest proteins that appear in the blood circulation in most systemic inflammatory conditions and this is the reason for its significance, even after identification of many organ specific inflammatory markers which appear relatively late during the course of disease. Earlier methods of CRP detection were based on the classical methods of antigen-antibody interaction through precipitation and agglutination reactions. Later on, CRP based enzymatic assays came into the picture which were further modified by integration of an antigen-antibody detection system with surface plasma spectroscopy. Then came the time for the development of electrochemical biosensors where nanomaterials were used to make a highly sensitive and portable detection system based on silicon nanowire, metal-oxide-semiconductor field-effect transistor/bipolar junction transistor, ZnS nanoparticle, aptamer, field emission transmitter, vertical flow immunoassay etc. This editorial attempts to summarize developments in the field of CRP detection, with a special emphasis on biosensor technology. This would help in translating the latest development in CRP detection in the clinical diagnosis of inflammatory conditions at an early onset of the diseases. PMID:25237625

  3. IRON-PEROXYMONOSULFATE: A NOVEL SULFATE RADICAL BASED ADVANCED OXIDATION TECHNOLOGY FOR DEGRADATION OF PCBS

    EPA Science Inventory

    This study investigates the degradation of recalcitrant polychlorinated biphenyl (PCBs) using sulfate radical-based advanced oxidation technologies. Sulfate radicals are generated through coupling of peroxymonosulfate (PMS) with iron (Fe(II), Fe(III)). Sulfate radicals have very ...

  4. Demonstrating Advanced Oxidation Coupled with Biodegradation for Removal of Carbamazepine (WERF Report INFR6SG09)

    EPA Science Inventory

    Carbamazepine is an anthropogenic pharmaceutical found in wastewater effluents that is quite resistant to removal by conventional wastewater treatment processes. Hydroxyl radical-based advanced oxidation processes can transform carbamazepine into degradation products but cannot m...

  5. Evaluation of Resin Dissolution Using an Advanced Oxidation Process - 13241

    SciTech Connect

    Goulart de Araujo, Leandro; Vicente de Padua Ferreira, Rafael; Takehiro Marumo, Julio; Passos Piveli, Roque; Campos, Fabio

    2013-07-01

    The ion-exchange resin is widely used in nuclear reactors, in cooling water purification and removing radioactive elements. Because of the long periods of time inside the reactor system, the resin becomes radioactive. When the useful life of them is over, its re-utilization becomes inappropriate, and for this reason, the resin is considered radioactive waste. The most common method of treatment is the immobilization of spent ion exchange resin in cement in order to form a solid monolithic matrix, which reduces the radionuclides release into the environment. However, the characteristic of contraction and expansion of the resin limits its incorporation in 10%, resulting in high cost in its direct immobilization. Therefore, it is recommended the utilization of a pre-treatment, capable of reducing the volume and degrading the resin, which would increase the load capacity in the immobilization. This work aims to develop a method of degradation of ion spent resins from the nuclear research reactor of Nuclear and Energy Research Institute (IPEN/CNEN-SP), Brazil, using the Advanced Oxidative Process (AOP) with Fenton's reagent (hydrogen peroxide and ferrous sulphate as catalyst). The resin evaluated was a mixture of cationic (IR 120P) and anionic (IRA 410) resins. The reactions were conducted by varying the concentration of the catalyst (25, 50, 100 e 150 mM) and the volume of the hydrogen peroxide, at three different temperatures, 50, 60 and 70 deg. C. The time of reaction was three hours. Total organic carbon content was determined periodically in order to evaluate the degradation as a function of time. The concentration of 50 mM of catalyst was the most effective in degrading approximately 99%, using up to 330 mL of hydrogen peroxide. The most effective temperature was about 60 deg. C, because of the decomposition of hydrogen peroxide in higher temperatures. TOC content was influenced by the concentration of the catalyst, interfering in the beginning of the degradation

  6. Oxidant-specific regulation of protein synthesis in Candida albicans.

    PubMed

    Sundaram, Arunkumar; Grant, Chris M

    2014-06-01

    Eukaryotic cells typically respond to stress conditions by inhibiting global protein synthesis. The initiation phase is the main target of regulation and represents a key control point for eukaryotic gene expression. In Saccharomyces cerevisiae and mammalian cells this is achieved by phosphorylation of eukaryotic initiation factor 2 (eIF2α). We have examined how the fungal pathogen Candida albicans responds to oxidative stress conditions and show that oxidants including hydrogen peroxide, the heavy metal cadmium and the thiol oxidant diamide inhibit translation initiation. The inhibition in response to hydrogen peroxide and cadmium largely depends on phosphorylation of eIF2α since minimal inhibition is observed in a gcn2 mutant. In contrast, translation initiation is inhibited in a Gcn2-independent manner in response to diamide. Our data indicate that all three oxidants inhibit growth of C. albicans in a dose-dependent manner, however, loss of GCN2 does not improve growth in the presence of hydrogen peroxide or cadmium. Examination of translational activity indicates that these oxidants inhibit translation at a post-initiation phase which may account for the growth inhibition in a gcn2 mutant. As well as inhibiting global translation initiation, phosphorylation of eIF2α also enhances expression of the GCN4 mRNA in yeast via a well-known translational control mechanism. We show that C. albicans GCN4 is similarly induced in response to oxidative stress conditions and Gcn4 is specifically required for hydrogen peroxide tolerance. Thus, the response of C. albicans to oxidative stress is mediated by oxidant-specific regulation of translation initiation and we discuss our findings in comparison to other eukaryotes including the yeast S. cerevisiae. PMID:24699161

  7. Attachment of Pathogenic Prion Protein to Model Oxide Surfaces

    PubMed Central

    Jacobson, Kurt H.; Kuech, Thomas R.; Pedersen, Joel A.

    2014-01-01

    Prions are the infectious agents in the class of fatal neurodegenerative diseases known as transmissible spongiform encephalopathies, which affect humans, deer, sheep, and cattle. Prion diseases of deer and sheep can be transmitted via environmental routes, and soil is has been implicated in the transmission of these diseases. Interaction with soil particles is expected to govern the transport, bioavailability and persistence of prions in soil environments. A mechanistic understanding of prion interaction with soil components is critical for understanding the behavior of these proteins in the environment. Here, we report results of a study to investigate the interactions of prions with model oxide surfaces (Al2O3, SiO2) using quartz crystal microbalance with dissipation monitoring and optical waveguide light mode spectroscopy. The efficiency of prion attachment to Al2O3 and SiO2 depended strongly on pH and ionic strength in a manner consistent with electrostatic forces dominating interaction with these oxides. The N-terminal portion of the protein appeared to facilitate attachment to Al2O3 under globally electrostatically repulsive conditions. We evaluated the utility of recombinant prion protein as a surrogate for prions in attachment experiments and found that its behavior differed markedly from that of the infectious agent. Our findings suggest that prions preferentially associate with positively charged mineral surfaces in soils (e.g., iron and aluminum oxides). PMID:23611152

  8. Protein topology determines cysteine oxidation fate: the case of sulfenyl amide formation among protein families.

    PubMed

    Defelipe, Lucas A; Lanzarotti, Esteban; Gauto, Diego; Marti, Marcelo A; Turjanski, Adrián G

    2015-03-01

    Cysteine residues have a rich chemistry and play a critical role in the catalytic activity of a plethora of enzymes. However, cysteines are susceptible to oxidation by Reactive Oxygen and Nitrogen Species, leading to a loss of their catalytic function. Therefore, cysteine oxidation is emerging as a relevant physiological regulatory mechanism. Formation of a cyclic sulfenyl amide residue at the active site of redox-regulated proteins has been proposed as a protection mechanism against irreversible oxidation as the sulfenyl amide intermediate has been identified in several proteins. However, how and why only some specific cysteine residues in particular proteins react to form this intermediate is still unknown. In the present work using in-silico based tools, we have identified a constrained conformation that accelerates sulfenyl amide formation. By means of combined MD and QM/MM calculation we show that this conformation positions the NH backbone towards the sulfenic acid and promotes the reaction to yield the sulfenyl amide intermediate, in one step with the concomitant release of a water molecule. Moreover, in a large subset of the proteins we found a conserved beta sheet-loop-helix motif, which is present across different protein folds, that is key for sulfenyl amide production as it promotes the previous formation of sulfenic acid. For catalytic activity, in several cases, proteins need the Cysteine to be in the cysteinate form, i.e. a low pKa Cys. We found that the conserved motif stabilizes the cysteinate by hydrogen bonding to several NH backbone moieties. As cysteinate is also more reactive toward ROS we propose that the sheet-loop-helix motif and the constraint conformation have been selected by evolution for proteins that need a reactive Cys protected from irreversible oxidation. Our results also highlight how fold conservation can be correlated to redox chemistry regulation of protein function. PMID:25741692

  9. Protein Topology Determines Cysteine Oxidation Fate: The Case of Sulfenyl Amide Formation among Protein Families

    PubMed Central

    Defelipe, Lucas A.; Lanzarotti, Esteban; Gauto, Diego; Marti, Marcelo A.; Turjanski, Adrián G.

    2015-01-01

    Cysteine residues have a rich chemistry and play a critical role in the catalytic activity of a plethora of enzymes. However, cysteines are susceptible to oxidation by Reactive Oxygen and Nitrogen Species, leading to a loss of their catalytic function. Therefore, cysteine oxidation is emerging as a relevant physiological regulatory mechanism. Formation of a cyclic sulfenyl amide residue at the active site of redox-regulated proteins has been proposed as a protection mechanism against irreversible oxidation as the sulfenyl amide intermediate has been identified in several proteins. However, how and why only some specific cysteine residues in particular proteins react to form this intermediate is still unknown. In the present work using in-silico based tools, we have identified a constrained conformation that accelerates sulfenyl amide formation. By means of combined MD and QM/MM calculation we show that this conformation positions the NH backbone towards the sulfenic acid and promotes the reaction to yield the sulfenyl amide intermediate, in one step with the concomitant release of a water molecule. Moreover, in a large subset of the proteins we found a conserved beta sheet-loop-helix motif, which is present across different protein folds, that is key for sulfenyl amide production as it promotes the previous formation of sulfenic acid. For catalytic activity, in several cases, proteins need the Cysteine to be in the cysteinate form, i.e. a low pKa Cys. We found that the conserved motif stabilizes the cysteinate by hydrogen bonding to several NH backbone moieties. As cysteinate is also more reactive toward ROS we propose that the sheet-loop-helix motif and the constraint conformation have been selected by evolution for proteins that need a reactive Cys protected from irreversible oxidation. Our results also highlight how fold conservation can be correlated to redox chemistry regulation of protein function. PMID:25741692

  10. Protein Footprinting by Carbenes on a Fast Photochemical Oxidation of Proteins (FPOP) Platform

    NASA Astrophysics Data System (ADS)

    Zhang, Bojie; Rempel, Don L.; Gross, Michael L.

    2016-03-01

    Protein footprinting combined with mass spectrometry provides a method to study protein structures and interactions. To improve further current protein footprinting methods, we adapted the fast photochemical oxidation of proteins (FPOP) platform to utilize carbenes as the footprinting reagent. A Nd-YAG laser provides 355 nm laser for carbene generation in situ from photoleucine as the carbene precursor in a flow system with calmodulin as the test protein. Reversed-phase liquid chromatography coupled with mass spectrometry is appropriate to analyze the modifications produced in this footprinting. By comparing the modification extent of apo and holo calmodulin on the peptide level, we can resolve different structural domains of the protein. Carbene footprinting in a flow system is promising.

  11. Myeloperoxidase activity and the oxidized proteins in blood neutrophils of patients with pneumonia.

    PubMed

    Muravlyova, Larissa; Molotov-Luchanskiy, Vilen; Bakirova, Ryszhan; Klyuyev, Dmitriy; Demidchik, Ludmila; Kolesnikova, Yevgeniya

    2014-10-01

    The main purpose of our investigation was to study myeloperoxidase activity and concentration of oxidized proteins in blood neutrophils of patients with ambulant pneumonia and secondary pneumonia which has arisen on a background of chronic obstructive pulmonary disease (COPD). Patients were divided into 2 groups. 17 patients with ambulant pneumonia moderate severity and respiratory insufficiency of grade 2 were included in the 1-st group. 20 COPD patients with secondary pneumonia moderate severity and with respiratory insufficiency of grade 2 were included in the 2-nd group. The control group consisted of 15 healthy subjects. The reactive protein carbonyl derivates, advanced oxidation protein products (AOPP) and myeloperoxidase activity were detected in neutrophils. In neutrophils of 1-st group patients the augmentation of reactive protein carbonyl derivates was observed in comparison with healthy ones. In neutrophils of 2-nd group patients the slight decrease of reactive protein carbonyl derivates was observed in comparison with healthy ones (by 17%). In neutrophils of 2-nd group patients the significant increasing AOPP in comparison with healthy ones (p <0.01) and 1 group patients (p <0.05) was fixed. Myeloperoxidase activity was higher in neutrophils of 1-th group patients in comparison with healthy ones. In neutrophils of 2-nd group patients myeloperoxidase activity was higher in comparison with the same of 1 group patients (by 67%, p <0.05). Our results showed the different direction of oxidized proteins formation neutrophils of patients with primary and secondary pneumonia. Besides that the varied degree of myeloperoxidase activity was fixed. Our results require more detailed understanding because they can reflect peculiar mechanisms of pneumonia development and determine the characteristics of their progression. PMID:26461373

  12. Chemical modifications of therapeutic proteins induced by residual ethylene oxide.

    PubMed

    Chen, Louise; Sloey, Christopher; Zhang, Zhongqi; Bondarenko, Pavel V; Kim, Hyojin; Ren, Da; Kanapuram, Sekhar

    2015-02-01

    Ethylene oxide (EtO) is widely used in sterilization of drug product primary containers and medical devices. The impact of residual EtO on protein therapeutics is of significant interest in the biopharmaceutical industry. The potential for EtO to modify individual amino acids in proteins has been previously reported. However, specific identification of EtO adducts in proteins and the effect of residual EtO on the stability of therapeutic proteins has not been reported to date. This paper describes studies of residual EtO with two therapeutic proteins, a PEGylated form of the recombinant human granulocyte colony-stimulating factor (Peg-GCSF) and recombinant human erythropoietin (EPO) formulated with human serum albumin (HSA). Peg-GCSF was filled in an EtO sterilized delivery device and incubated at accelerated stress conditions. Glu-C peptide mapping and LC-MS analyses revealed residual EtO reacted with Peg-GCSF and resulted in EtO modifications at two methionine residues (Met-127 and Met-138). In addition, tryptic peptide mapping and LC-MS analyses revealed residual EtO in plastic vials reacted with HSA in EPO formulation at Met-328 and Cys-34. This paper details the work conducted to understand the effects of residual EtO on the chemical stability of protein therapeutics. PMID:25407640

  13. Influence of protein type on oxidation and digestibility of fish oil-in-water emulsions: gliadin, caseinate, and whey protein.

    PubMed

    Qiu, Chaoying; Zhao, Mouming; Decker, Eric Andrew; McClements, David Julian

    2015-05-15

    The influence of three surface-active proteins on the oxidative stability and lipase digestibility of emulsified ω-3 oils was examined: deamidated wheat gliadin (gliadin); sodium caseinate (CN); whey protein isolate (WPI). Gliadin and WPI were more effective at inhibiting lipid oxidation (hydroperoxides and TBARS) of fish oil-in-water emulsions than CN. Protein oxidation during storage was determined by measuring the loss of tryptophan fluorescence. The CN-emulsions exhibited the highest loss of tryptophan fluorescence during aging, as well as the highest amount of lipid oxidation. Potential reasons for the differences in oxidative stability of the emulsions with different proteins include differences in interfacial film thickness, protein chelating ability, and antioxidant amino acids profiles. During in vitro digestion, gliadin-stabilized emulsions had the lowest digestion rate of the three proteins. These results have important implications for using proteins to fabricate emulsion-based delivery systems for ω-3 oils. PMID:25577077

  14. Affinity chromatographic selection of carbonylated proteins followed by identification of oxidation sites using tandem mass spectrometry.

    PubMed

    Mirzaei, Hamid; Regnier, Fred

    2005-04-15

    It has been shown that oxidatively modified forms of proteins accumulate during oxidative stress, aging, and in some age-related diseases. One of the unique features of a wide variety of routes by which proteins are oxidized is the generation of carbonyl groups. This paper reports a method for the isolation of oxidized proteins, which involves (1) biotinylation of oxidized proteins with biotin hydrazide and (2) affinity enrichment using monomeric avidin affinity chromatography columns. The selectivity of the method was validated by adding in vitro oxidized biotinylated BSA to a yeast lysate and showing that the predominant protein recovered was BSA. This method was applied to the question of whether large doses of 2-nitropropane produce oxidized proteins. A study of rat liver homogenates showed that animals dosed with 2-nitropropane produced 17 times more oxidized protein than controls in 6 h. Tryptic digestion of these oxidized proteins followed by reversed-phase chromatography and tandem mass spectrometry led to the identification of 14 peptides and their parent proteins. Nine of the 14 identified peptides were found to carry 1 or 2 oxidation sites and 5 of the 9 peptides were biotinylated. The significance of this affinity method is that it allows the isolation of oxidized proteins from the rest of the proteome and facilitates their identification. In some cases, it is even possible to identify the site of oxidation. PMID:15828771

  15. Recent advances in the analysis of therapeutic proteins by capillary and microchip electrophoresis

    PubMed Central

    Creamer, Jessica S.; Oborny, Nathan J.; Lunte, Susan M.

    2014-01-01

    The development of therapeutic proteins and peptides is an expensive and time-intensive process. Biologics, which have become a multi-billion dollar industry, are chemically complex products that require constant observation during each stage of development and production. Post-translational modifications along with chemical and physical degradation from oxidation, deamidation, and aggregation, lead to high levels of heterogeneity that affect drug quality and efficacy. The various separation modes of capillary electrophoresis (CE) are commonly utilized to perform quality control and assess protein heterogeneity. This review attempts to highlight the most recent developments and applications of CE separation techniques for the characterization of protein and peptide therapeutics by focusing on papers accepted for publication in the in the two-year period between January 2012 and December 2013. The separation principles and technological advances of CE, capillary gel electrophoresis, capillary isoelectric focusing, capillary electrochromatography and CE-mass spectrometry are discussed, along with exciting new applications of these techniques to relevant pharmaceutical issues. Also included is a small selection of papers on microchip electrophoresis to show the direction this field is moving with regards to the development of inexpensive and portable analysis systems for on-site, high-throughput analysis. PMID:25126117

  16. Recent anode advances in solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Sun, Chunwen; Stimming, Ulrich

    Solid oxide fuel cells (SOFCs) are electrochemical reactors that can directly convert the chemical energy of a fuel gas into electrical energy with high efficiency and in an environment-friendly way. The recent trends in the research of solid oxide fuel cells concern the use of available hydrocarbon fuels, such as natural gas. The most commonly used anode material Ni/YSZ cermet exhibits some disadvantages when hydrocarbons were used as fuels. Thus it is necessary to develop alternative anode materials which display mixed conductivity under fuel conditions. This article reviews the recent developments of anode in SOFCs with principal emphasis on the material aspects. In addition, the mechanism and kinetics of fuel oxidation reactions are also addressed. Various processes used for the cost-effective fabrication of anode have also been summarized. Finally, this review will be concluded with personal perspectives on the future research directions of this area.

  17. Moringa oleifera aqueous leaf extract inhibits reducing monosaccharide-induced protein glycation and oxidation of bovine serum albumin.

    PubMed

    Nunthanawanich, Pornpimon; Sompong, Weerachat; Sirikwanpong, Sukrit; Mäkynen, Kittana; Adisakwattana, Sirichai; Dahlan, Winai; Ngamukote, Sathaporn

    2016-01-01

    Advanced glycation end products (AGEs) play an important factor for pathophysiology of diabetes and its complications. Moringa oleifera is one of the medicinal plants that have anti-hyperglycemic activity. However, anti-glycation property of Moringa oleifera leaf extract on the different types of reducing monosaccharides-induced protein glycation has not been investigated. Therefore, the aim of this study was to examine the protective effect of Moringa oleifera aqueous leaf extract (MOE) on reducing sugars-induced protein glycation and protein oxidation. Total phenolic content of MOE was measured using the Folin-Ciocalteu method. Bovine serum albumin was incubated with 0.5 M of reducing sugars (glucose or fructose) with or without MOE (0.5-2.0 mg/mL) for 1, 2, 3 and 4 weeks. The results found that total phenolic content was 38.56 ± 1.50 mg gallic acid equivalents/g dry extract. The formation of fluorescent and non-fluorescent AGEs [N (ε)-(carboxymethyl) lysine (CML)] and the level of fructosamine were determined to indicate protein glycation, whereas the level of protein carbonyl content and thiol group were examined for protein oxidation. MOE (0.5-2.0 mg/mL) significantly inhibited the formation of fluorescent, N (ε)-CML and markedly decreased fructosamine level (P < 0.05). Moreover, MOE significantly prevented protein oxidation manifested by reducing protein carbonyl and the depletion of protein thiol in a dose-dependent manner (P < 0.05). Thus, the findings indicated that polyphenols containing in MOE have high potential for decreasing protein glycation and protein oxidation that may delay or prevent AGE-related diabetic complications. PMID:27468399

  18. Polyethyleneimine-modified graphene oxide nanocomposites for effective protein functionalization

    NASA Astrophysics Data System (ADS)

    Weng, Yejing; Jiang, Bo; Yang, Kaiguang; Sui, Zhigang; Zhang, Lihua; Zhang, Yukui

    2015-08-01

    A facile method to prepare a biocompatible graphene oxide (GO)-based substrate for protein immobilization was developed to overcome the drawbacks of GO, such as the strong electrostatic and hydrophobic interactions which could potentially alter the conformation and biological activity of proteins. The GO was coated with hydrophilic branched polyethyleneimine (BPEI), while Concanavalin A (Con A) as a model lectin protein was employed to fabricate the functionalized composites to evaluate the feasibility of this strategy. The composites exhibit an extremely high binding capacity for glycoproteins (i.e. IgG 538.3 mg g-1), which are superior to other immobilized materials. Moreover, they can work well in 500-fold non-glycoprotein interference and even in complex biological samples. All these data suggest that the GO@BPEI composites will have great potential as scaffolds for proteins fully exerting their biofunctions.A facile method to prepare a biocompatible graphene oxide (GO)-based substrate for protein immobilization was developed to overcome the drawbacks of GO, such as the strong electrostatic and hydrophobic interactions which could potentially alter the conformation and biological activity of proteins. The GO was coated with hydrophilic branched polyethyleneimine (BPEI), while Concanavalin A (Con A) as a model lectin protein was employed to fabricate the functionalized composites to evaluate the feasibility of this strategy. The composites exhibit an extremely high binding capacity for glycoproteins (i.e. IgG 538.3 mg g-1), which are superior to other immobilized materials. Moreover, they can work well in 500-fold non-glycoprotein interference and even in complex biological samples. All these data suggest that the GO@BPEI composites will have great potential as scaffolds for proteins fully exerting their biofunctions. Electronic supplementary information (ESI) available: Cell viability assay, enrichment of standard glycoprotein, pretreatment and analysis of real

  19. SO(2) inhalation induces protein oxidation, DNA-protein crosslinks and apoptosis in rat hippocampus.

    PubMed

    Sang, Nan; Hou, Li; Yun, Yang; Li, Guangke

    2009-03-01

    Previous studies provide evidence for the possible neurotoxicity of SO(2), but little information is available about its mechanisms. In the present study, SO(2) inhalation-induced effects on the protein oxidation, DNA-protein crosslinks and apoptosis in rat hippocampus were studied, by exposing Wistar rats to SO(2) at 14, 28 and 56mg/m(3). The results indicate that the protein carbonyl content, an indicator of protein oxidation, and DNA-protein crosslink coefficient were significantly augmented with concentration-dependent properties. In addition, SO(2) inhalation at all concentrations tested caused the increases of caspase-3 activity and number of TUNEL positive staining neuron and the statistical difference was observed after 28 and 56mg/m(3) exposure, suggesting the occurrence of apoptosis. The results imply that attacking protein, nucleic acids and lipids by free radicals, generated via SO(2) derivatives in vivo, is one of the main mechanisms for SO(2)-induced injuries in central neuronal system. PMID:18722661

  20. Electron flow through biological molecules: Does hole hopping protect proteins from oxidative damage?

    PubMed Central

    Winkler, Jay R.; Gray, Harry B.

    2016-01-01

    Biological electron transfers often occur between metal-containing cofactors that are separated by very large molecular distances. Employing photosensitizer-modified iron and copper proteins, we have shown that single-step electron tunneling can occur on nanosecond to microsecond timescales at distances between 15 and 20 angstroms. We also have shown that charge transport can occur over even longer distances by hole hopping (multistep tunneling) through intervening tyrosines and tryptophans. In this Perspective, we advance the hypothesis that such hole hopping through Tyr/Trp chains could protect oxygenase, dioxygenase, and peroxidase enzymes from oxidative damage. In support of this view, by examining the structures of P450 (CYP102A) and 2OG-Fe (TauD) enzymes, we have identified candidate Tyr/Trp chains that could transfer holes from uncoupled high-potential intermediates to reductants in contact with protein surface sites. PMID:26537399

  1. Protein Tyrosine Nitration and Thiol Oxidation by Peroxynitrite—Strategies to Prevent These Oxidative Modifications

    PubMed Central

    Daiber, Andreas; Daub, Steffen; Bachschmid, Markus; Schildknecht, Stefan; Oelze, Matthias; Steven, Sebastian; Schmidt, Patrick; Megner, Alexandra; Wada, Masayuki; Tanabe, Tadashi; Münzel, Thomas; Bottari, Serge; Ullrich, Volker

    2013-01-01

    The reaction product of nitric oxide and superoxide, peroxynitrite, is a potent biological oxidant. The most important oxidative protein modifications described for peroxynitrite are cysteine-thiol oxidation and tyrosine nitration. We have previously demonstrated that intrinsic heme-thiolate (P450)-dependent enzymatic catalysis increases the nitration of tyrosine 430 in prostacyclin synthase and results in loss of activity which contributes to endothelial dysfunction. We here report the sensitive peroxynitrite-dependent nitration of an over-expressed and partially purified human prostacyclin synthase (3.3 μM) with an EC50 value of 5 μM. Microsomal thiols in these preparations effectively compete for peroxynitrite and block the nitration of other proteins up to 50 μM peroxynitrite. Purified, recombinant PGIS showed a half-maximal nitration by 10 μM 3-morpholino sydnonimine (Sin-1) which increased in the presence of bicarbonate, and was only marginally induced by freely diffusing NO2-radicals generated by a peroxidase/nitrite/hydrogen peroxide system. Based on these observations, we would like to emphasize that prostacyclin synthase is among the most efficiently and sensitively nitrated proteins investigated by us so far. In the second part of the study, we identified two classes of peroxynitrite scavengers, blocking either peroxynitrite anion-mediated thiol oxidations or phenol/tyrosine nitrations by free radical mechanisms. Dithiopurines and dithiopyrimidines were highly effective in inhibiting both reaction types which could make this class of compounds interesting therapeutic tools. In the present work, we highlighted the impact of experimental conditions on the outcome of peroxynitrite-mediated nitrations. The limitations identified in this work need to be considered in the assessment of experimental data involving peroxynitrite. PMID:23567270

  2. The muscle oxidative regulatory response to acute exercise is not impaired in less advanced COPD despite a decreased oxidative phenotype.

    PubMed

    Slot, Ilse G M; van den Borst, Bram; Hellwig, Valéry A C V; Barreiro, Esther; Schols, Annemie M W J; Gosker, Harry R

    2014-01-01

    Already in an early disease stage, patients with chronic obstructive pulmonary disease (COPD) are confronted with impaired skeletal muscle function and physical performance due to a loss of oxidative type I muscle fibers and oxidative capacity (i.e. oxidative phenotype; Oxphen). Physical activity is a well-known stimulus of muscle Oxphen and crucial for its maintenance. We hypothesized that a blunted response of Oxphen genes to an acute bout of exercise could contribute to decreased Oxphen in COPD. For this, 28 patients with less advanced COPD (age 65 ± 7 yrs, FEV1 59 ± 16% predicted) and 15 age- and gender-matched healthy controls performed an incremental cycle ergometry test. The Oxphen response to exercise was determined by the measurement of gene expression levels of Oxphen markers in pre and 4h-post exercise quadriceps biopsies. Because exercise-induced hypoxia and oxidative stress may interfere with Oxphen response, oxygen saturation and oxidative stress markers were assessed as well. Regardless of oxygen desaturation and absolute exercise intensities, the Oxphen regulatory response to exercise was comparable between COPD patients and controls with no evidence of increased oxidative stress. In conclusion, the muscle Oxphen regulatory response to acute exercise is not blunted in less advanced COPD, regardless of exercise-induced hypoxia. Hence, this study provides further rationale for incorporation of exercise training as integrated part of disease management to prevent or slow down loss of muscle Oxphen and related functional impairment in COPD. PMID:24587251

  3. TET proteins and 5-methylcytosine oxidation in the immune system

    PubMed Central

    Tsagaratou, Ageliki; Rao, Anjana

    2015-01-01

    DNA methylation in the form of 5-methylcytosine (5mC) is essential for normal development in mammals and influences a variety of biological processes including transcriptional regulation, imprinting and the maintenance of genomic stability. The recent discovery of TET proteins, which oxidize 5mC to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC), has changed our understanding of the process of DNA demethylation. Here, we summarize our current knowledge of the roles of DNA methylation and TET proteins in cell differentiation and function. The intensive research on this subject has so far focused primarily on ES cells and neurons. Here we summarize what is known about DNA methylation in T cell function. PMID:24619230

  4. Serum levels of nitric oxide and protein oxidation in goats seropositive for Toxoplasma gondii and Neospora caninum.

    PubMed

    Tonin, A A; Weber, A; Ribeiro, A; Camillo, G; Vogel, F F; Moura, A B; Bochi, G V; Moresco, R N; Da Silva, A S

    2015-08-01

    The aim of this study was to assess and analyze the levels of nitric oxide (NO) and advanced oxidation protein products (AOPP) in serum of goats naturally infected by Toxoplasma gondii, Neospora caninum, or concomitantly infected by these two parasites. Thus, it was measured NOx and AOPP levels in twenty (n=20) sera samples of goats seronegative for T. gondii and N. caninum [negative control group (A)]; while the positive groups were composed by sera of infected animals, twelve (n=12) seropositive for N. caninum [group B]; eighteen (n=18) positive for T. gondii [group C]; and thirteen (n=13) seropositive for N. caninum and T. gondii [group D]. As results, it was observed that animals seropositive for N. caninum and T. gondii (Groups B to D) showed higher serum levels of NOx (P<0.001; F=9.5), when compared with seronegative animals. Additionally, it was observed a positive correlation between NOx levels and antibodies titrations for N. caninum (P<0.01; r=0.68) and T. gondii (P<0.05; r=0.56). AOPP levels were increase in groups C and D (P>0.05). Interestingly, group B did not show increase in AOPP, what led us to hypothesize that the major protein damage is linked to T. gondii infection. Therefore, our results showed an increased in NOx levels, which was probably related to the immune response, since it is an important inflammatory mediator; and AOPP were increased in groups where there was seropositivity for T. gondii, but not for the group composed only by animals seropositive for N. caninum, allowing us to suggest higher protein damage in toxoplasmosis. PMID:26031474

  5. Mechanisms of Oxidative Protein Folding in the Bacterial Cell Envelope

    PubMed Central

    2010-01-01

    Abstract Disulfide-bond formation is important for the correct folding of a great number of proteins that are exported to the cell envelope of bacteria. Bacterial cells have evolved elaborate systems to promote the joining of two cysteines to form a disulfide bond and to repair misoxidized proteins. In the past two decades, significant advances have occurred in our understanding of the enzyme systems (DsbA, DsbB, DsbC, DsbG, and DsbD) used by the gram-negative bacterium Escherichia coli to ensure that correct pairs of cysteines are joined during the process of protein folding. However, a number of fundamental questions about these processes remain, especially about how they occur inside the cell. In addition, recent recognition of the increasing diversity among bacteria in the disulfide bond–forming capacity and in the systems for introducing disulfide bonds into proteins is raising new questions. We review here the marked progress in this field and discuss important questions that remain for future studies. Antioxid. Redox Signal. 13, 1231–1246. PMID:20367276

  6. Advancing translational research with next-generation protein microarrays.

    PubMed

    Yu, Xiaobo; Petritis, Brianne; LaBaer, Joshua

    2016-04-01

    Protein microarrays are a high-throughput technology used increasingly in translational research, seeking to apply basic science findings to enhance human health. In addition to assessing protein levels, posttranslational modifications, and signaling pathways in patient samples, protein microarrays have aided in the identification of potential protein biomarkers of disease and infection. In this perspective, the different types of full-length protein microarrays that are used in translational research are reviewed. Specific studies employing these microarrays are presented to highlight their potential in finding solutions to real clinical problems. Finally, the criteria that should be considered when developing next-generation protein microarrays are provided. PMID:26749402

  7. High-Throughput Screening in Protein Engineering: Recent Advances and Future Perspectives

    PubMed Central

    Wójcik, Magdalena; Telzerow, Aline; Quax, Wim J.; Boersma, Ykelien L.

    2015-01-01

    Over the last three decades, protein engineering has established itself as an important tool for the development of enzymes and (therapeutic) proteins with improved characteristics. New mutagenesis techniques and computational design tools have greatly aided in the advancement of protein engineering. Yet, one of the pivotal components to further advance protein engineering strategies is the high-throughput screening of variants. Compartmentalization is one of the key features allowing miniaturization and acceleration of screening. This review focuses on novel screening technologies applied in protein engineering, highlighting flow cytometry- and microfluidics-based platforms. PMID:26492240

  8. Neutrophil-generated oxidative stress and protein damage in Staphylococcus aureus.

    PubMed

    Beavers, William N; Skaar, Eric P

    2016-08-01

    Staphylococcus aureus is a ubiquitous, versatile and dangerous pathogen. It colonizes over 30% of the human population, and is one of the leading causes of death by an infectious agent. During S. aureus colonization and invasion, leukocytes are recruited to the site of infection. To combat S. aureus, leukocytes generate an arsenal of reactive species including superoxide, hydrogen peroxide, nitric oxide and hypohalous acids that modify and inactivate cellular macromolecules, resulting in growth defects or death. When S. aureus colonization cannot be cleared by the immune system, antibiotic treatment is necessary and can be effective. Yet, this organism quickly gains resistance to each new antibiotic it encounters. Therefore, it is in the interest of human health to acquire a deeper understanding of how S. aureus evades killing by the immune system. Advances in this field will have implications for the design of future S. aureus treatments that complement and assist the host immune response. In that regard, this review focuses on how S. aureus avoids host-generated oxidative stress, and discusses the mechanisms used by S. aureus to survive oxidative damage including antioxidants, direct repair of damaged proteins, sensing oxidant stress and transcriptional changes. This review will elucidate areas for studies to identify and validate future antimicrobial targets. PMID:27354296

  9. Oxidative stress, redox signaling pathways, and autophagy in cachectic muscles of male patients with advanced COPD and lung cancer.

    PubMed

    Puig-Vilanova, Ester; Rodriguez, Diego A; Lloreta, Josep; Ausin, Pilar; Pascual-Guardia, Sergio; Broquetas, Joan; Roca, Josep; Gea, Joaquim; Barreiro, Esther

    2015-02-01

    Muscle dysfunction and wasting are predictors of mortality in advanced COPD and malignancies. Redox imbalance and enhanced protein catabolism are underlying mechanisms in COPD. We hypothesized that the expression profile of several biological markers share similarities in patients with cachexia associated with either COPD or lung cancer (LC). In vastus lateralis of cachectic patients with either LC (n=10) or advanced COPD (n=16) and healthy controls (n=10), markers of redox balance, inflammation, proteolysis, autophagy, signaling pathways, mitochondrial function, muscle structure, and sarcomere damage were measured using laboratory and light and electron microscopy techniques. Systemic redox balance and inflammation were also determined. All subjects were clinically evaluated. Compared to controls, in both cachectic groups of patients, a similar expression profile of different biological markers was observed in their muscles: increased levels of muscle protein oxidation and ubiquitination (p<0.05, both), which positively correlated (r=0.888), redox-sensitive signaling pathways (NF-κB and FoxO) were activated (p<0.05, all), fast-twitch fiber sizes were atrophied, muscle structural abnormalities and sarcomere disruptions were significantly greater (p<0.05, both). Structural and functional protein levels were lower in muscles of both cachectic patient groups than in controls (p<0.05, all). However, levels of autophagy markers including ultrastructural autophagosome counts were increased only in muscles of cachectic COPD patients (p<0.05). Systemic oxidative stress and inflammation levels were also increased in both patient groups compared to controls (p<0.005, both). Oxidative stress and redox-sensitive signaling pathways are likely to contribute to the etiology of muscle wasting and sarcomere disruption in patients with respiratory cachexia: LC and COPD. PMID:25464271

  10. Advanced Glycation End Products and Oxidative Stress in Type 2 Diabetes Mellitus

    PubMed Central

    Nowotny, Kerstin; Jung, Tobias; Höhn, Annika; Weber, Daniela; Grune, Tilman

    2015-01-01

    Type 2 diabetes mellitus (T2DM) is a very complex and multifactorial metabolic disease characterized by insulin resistance and β cell failure leading to elevated blood glucose levels. Hyperglycemia is suggested to be the main cause of diabetic complications, which not only decrease life quality and expectancy, but are also becoming a problem regarding the financial burden for health care systems. Therefore, and to counteract the continually increasing prevalence of diabetes, understanding the pathogenesis, the main risk factors, and the underlying molecular mechanisms may establish a basis for prevention and therapy. In this regard, research was performed revealing further evidence that oxidative stress has an important role in hyperglycemia-induced tissue injury as well as in early events relevant for the development of T2DM. The formation of advanced glycation end products (AGEs), a group of modified proteins and/or lipids with damaging potential, is one contributing factor. On the one hand it has been reported that AGEs increase reactive oxygen species formation and impair antioxidant systems, on the other hand the formation of some AGEs is induced per se under oxidative conditions. Thus, AGEs contribute at least partly to chronic stress conditions in diabetes. As AGEs are not only formed endogenously, but also derive from exogenous sources, i.e., food, they have been assumed as risk factors for T2DM. However, the role of AGEs in the pathogenesis of T2DM and diabetic complications—if they are causal or simply an effect—is only partly understood. This review will highlight the involvement of AGEs in the development and progression of T2DM and their role in diabetic complications. PMID:25786107

  11. Expression of the Receptor for Advanced Glycation End Products in Oligodendrocytes in Response to Oxidative Stress

    PubMed Central

    Qin, Jingdong; Goswami, Rajendra; Dawson, Sylvia; Dawson, Glyn

    2008-01-01

    Demyelination is a common result of oxidative stress in the nervous system, and we report here that the response of oligodendrocytes to oxidative stress involves the receptor for advanced glycation end products (RAGE). RAGE has not previously been reported in neonatal rat oligodendrocytes (NRO), but, by using primers specific for rat RAGE, we were able to show expression of messenger RNA (mRNA) for RAGE in NRO, and a 55-kDa protein was detected by Western blotting with antibodies to RAGE. Neonatal rat oligodendrocytes stained strongly for RAGE, suggesting membrane localization of RAGE. Addition of low concentrations of hydrogen peroxide (100 μM) initiated 55-kDa RAGE shedding from the cell membrane and the appearance of “soluble” 45-kDa RAGE in the culture medium, followed by restoration of RAGE expression to normal levels. Increasing hydrogen peroxide concentration (>200 μM) resulted in no restoration of RAGE, and the cells underwent apoptosis and necrosis. We further confirmed the observation in a human oligodendroglioma-derived (HOG) cell line. Both the antioxidant N-acetyl-L-cysteine and the broad-spectrum metalloproteases inhibitor TAPI0 were able partially to inhibit shedding of RAGE, suggesting involvement of metalloproteases in cleavage to produce soluble RAGE. The level of 55-kDa RAGE in autopsy brain of patients undergoing neurodegeneration with accompanying inflammation [multiple sclerosis and neuronal ceroid-lipofuscinosis (Batten's disease)] was much lower than that in age-matched controls, suggesting that shedding of RAGE might occur as reactive oxygen species accumulate in brain cells and be part of the process of neurodegeneration. PMID:18438937

  12. TET proteins and 5-methylcytosine oxidation in hematological cancers

    PubMed Central

    An, Jungeun; Pastor, William A.; Ko, Myunggon; Rao, Anjana

    2015-01-01

    Summary DNA methylation has pivotal regulatory roles in mammalian development, retrotransposon silencing, genomic imprinting and X-chromosome inactivation. Cancer cells display highly dysregulated DNA methylation profiles characterized by global hypomethylation in conjunction with hypermethylation of promoter CpG islands (CGIs) that presumably lead to genome instability and aberrant expression of tumor suppressor genes or oncogenes. The recent discovery of Ten-Eleven-Translocation (TET) family dioxygenases that oxidize 5mC to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC) in DNA has led to profound progress in understanding the mechanism underlying DNA demethylation. Among the three TET genes, TET2 recurrently undergoes inactivating mutations in a wide range of myeloid and lymphoid malignancies. TET2 functions as a bona fide tumor suppressor particularly in the pathogenesis of myeloid malignancies resembling chronic myelomoncytic leukemia (CMML) and myelodysplastic syndromes (MDS) in human. Here we review diverse functions of TET proteins and the novel epigenetic marks that they generate in DNA methylation/demethylation dynamics and normal and malignant hematopoietic differentiation. The impact of TET2 inactivation in hematopoiesis and various mechanisms modulating the expression or activity of TET proteins are also discussed. Furthermore, we also present evidence that TET2 and TET3 collaborate to suppress aberrant hematopoiesis and hematopoietic transformation. A detailed understanding of the normal and pathological functions of TET proteins may provide new avenues to develop novel epigenetic therapies for treating hematological malignancies. PMID:25510268

  13. Development of an advanced bond coat for solid oxide fuel cell interconnector applications

    NASA Astrophysics Data System (ADS)

    Yeh, An-Chou; Chen, Yu-Ming; Liu, Chien-Kuo; Shong, Wei-Ja

    2015-11-01

    An advanced bond coat has been developed for solid oxide fuel cell interconnector applications; a low thermal expansion superalloy has been selected as the substrate, and the newly developed bond coat is applied between the substrate and the LSM top coat. The bond coat composition is designed to be near thermodynamic equilibrium with the substrate to minimize interdiffusion with the substrate while providing oxidation protection for the substrate. The bond coat exhibits good oxidation resistance, a low area specific resistance, and a low thermal expansion coefficient at 800 °C; experimental results indicate that interdiffusion between the bond coat and the substrate can be hindered.

  14. An Integrated Framework Advancing Membrane Protein Modeling and Design

    PubMed Central

    Weitzner, Brian D.; Duran, Amanda M.; Tilley, Drew C.; Elazar, Assaf; Gray, Jeffrey J.

    2015-01-01

    Membrane proteins are critical functional molecules in the human body, constituting more than 30% of open reading frames in the human genome. Unfortunately, a myriad of difficulties in overexpression and reconstitution into membrane mimetics severely limit our ability to determine their structures. Computational tools are therefore instrumental to membrane protein structure prediction, consequently increasing our understanding of membrane protein function and their role in disease. Here, we describe a general framework facilitating membrane protein modeling and design that combines the scientific principles for membrane protein modeling with the flexible software architecture of Rosetta3. This new framework, called RosettaMP, provides a general membrane representation that interfaces with scoring, conformational sampling, and mutation routines that can be easily combined to create new protocols. To demonstrate the capabilities of this implementation, we developed four proof-of-concept applications for (1) prediction of free energy changes upon mutation; (2) high-resolution structural refinement; (3) protein-protein docking; and (4) assembly of symmetric protein complexes, all in the membrane environment. Preliminary data show that these algorithms can produce meaningful scores and structures. The data also suggest needed improvements to both sampling routines and score functions. Importantly, the applications collectively demonstrate the potential of combining the flexible nature of RosettaMP with the power of Rosetta algorithms to facilitate membrane protein modeling and design. PMID:26325167

  15. An Integrated Framework Advancing Membrane Protein Modeling and Design.

    PubMed

    Alford, Rebecca F; Koehler Leman, Julia; Weitzner, Brian D; Duran, Amanda M; Tilley, Drew C; Elazar, Assaf; Gray, Jeffrey J

    2015-09-01

    Membrane proteins are critical functional molecules in the human body, constituting more than 30% of open reading frames in the human genome. Unfortunately, a myriad of difficulties in overexpression and reconstitution into membrane mimetics severely limit our ability to determine their structures. Computational tools are therefore instrumental to membrane protein structure prediction, consequently increasing our understanding of membrane protein function and their role in disease. Here, we describe a general framework facilitating membrane protein modeling and design that combines the scientific principles for membrane protein modeling with the flexible software architecture of Rosetta3. This new framework, called RosettaMP, provides a general membrane representation that interfaces with scoring, conformational sampling, and mutation routines that can be easily combined to create new protocols. To demonstrate the capabilities of this implementation, we developed four proof-of-concept applications for (1) prediction of free energy changes upon mutation; (2) high-resolution structural refinement; (3) protein-protein docking; and (4) assembly of symmetric protein complexes, all in the membrane environment. Preliminary data show that these algorithms can produce meaningful scores and structures. The data also suggest needed improvements to both sampling routines and score functions. Importantly, the applications collectively demonstrate the potential of combining the flexible nature of RosettaMP with the power of Rosetta algorithms to facilitate membrane protein modeling and design. PMID:26325167

  16. Dietary advanced lipid oxidation endproducts are risk factors to human health.

    PubMed

    Kanner, Joseph

    2007-09-01

    Lipid oxidation in foods is one of the major degradative processes responsible for losses in food quality. The oxidation of unsaturated fatty acids results in significant generation of dietary advanced lipid oxidation endproducts (ALEs) which are in part cytotoxic and genotoxic compounds. The gastrointestinal tract is constantly exposed to dietary oxidized food compounds, after digestion a part of them are absorbed into the lymph or directly into the blood stream. After ingestion of oxidized fats animals and human have been shown to excrete in urine increase amounts of malondialdehyde but also lipophilic carbonyl compounds. Oxidized cholesterol in the diet was found to be a source of oxidized lipoproteins in human serum. Some of the dietary ALEs, which are absorbed from the gut to the circulatory system, seems to act as injurious chemicals that activate an inflammatory response which affects not only circulatory system but also organs such as liver, kidney, lung, and the gut itself. We believe that repeated consumption of oxidized fat in the diet poses a chronic threat to human health. High concentration of dietary antioxidants could prevent lipid oxidation and ALEs generation not only in foods but also in stomach condition and thereby potentially decrease absorption of ALEs from the gut. This could explains the health benefit of diets containing large amounts of dietary antioxidants such those present in fruits and vegetables, or products such as red-wine or tea consuming during the meal. PMID:17854006

  17. A comparison of single oxidants versus advanced oxidation processes as chlorine-alternatives for wild blueberry processing (Vaccinium angustifolium).

    PubMed

    Crowe, Kristi M; Bushway, Alfred A; Bushway, Rodney J; Davis-Dentici, Katherine; Hazen, Russell A

    2007-05-01

    Advanced oxidation processes and single chemical oxidants were evaluated for their antimicrobial efficacy against common spoilage bacteria isolated from lowbush blueberries. Predominant bacterial flora were identified using biochemical testing with the assessment of relative abundance using non-selective and differential media. Single chemical oxidants evaluated for postharvest processing of lowbush blueberries included 1% hydrogen peroxide, 100 ppm chlorine, and 1 ppm aqueous ozone while advanced oxidation processes (AOPs) included combinations of 1% hydrogen peroxide/UV, 100 ppm chlorine/UV, and 1 ppm ozone/1% hydrogen peroxide/UV. Enterobacter agglomerans and Pseudomonas fluorescens were found to comprise 90-95% of the bacterial flora on lowbush blueberries. Results of inoculation studies reveal significant log reductions (p< or 5) in populations of E. agglomerans and P. fluorescens on all samples receiving treatment with 1% hydrogen peroxide, 1% hydrogen peroxide/UV, 1 ppm ozone, or a combined ozone/hydrogen peroxide/UV treatment as compared to chlorine treatments and unwashed control berries. Although population reductions approached 2.5 log CFU/g, microbial reductions among these treatments were not found to be significantly different (p< or 5) from each other despite the synergistic potential that should result from AOPs; furthermore, as a single oxidant, UV inactivation of inoculated bacteria was minimal and did not prove effective as a non-aqueous bactericidal process for fresh pack blueberries. Overall, results indicate that hydrogen peroxide and ozone, as single chemical oxidants, are as effective as AOPs and could be considered as chlorine-alternatives in improving the microbiological quality of lowbush blueberries. PMID:17350128

  18. ADVANCED OXIDATION AND REDUCTION PROCESSES IN THE GAS PHASE USING NON-THERMAL PLASMAS

    EPA Science Inventory

    In the past several years interest in gas-phase pollution control has increased, arising from a larger body of regulations and greater respect for the environment. Advanced oxidation technologies (AOTs), historically used to treat recalcitrant water pollutants via hydroxyl-radica...

  19. DEMONSTRATION OF THE HIPOX ADVANCED OXIDATION TECHNOLOGY FOR THE TREATMENT OF MTBE-CONTAMINATED GROUNDWATER

    EPA Science Inventory

    The HiPOx technology is an advanced oxidation process that incorporates high-precision delivery of ozone and hydrogen peroxide to chemically destroy organic contaminants with the promise of minimizing bromate formation. A MTBE-contaminated groundwater from the Ventura County Nava...

  20. TiO2-Based Advanced Oxidation Nanotechnologies For Water Purification And Reuse

    EPA Science Inventory

    TiO2 photocatalysis, one of the UV-based advanced oxidation technologies (AOTs) and nanotechnologies (AONs), has attracted great attention for the development of efficient water treatment and purification systems due to the effectiveness of TiO2 to generate ...

  1. DEMONSTRATION OF THE HIPOX ADVANCED OXIDATION TECHNOLOGY FOR THE TREATMENT OF MTBE-CONTAMINATED GROUNDWATER

    EPA Science Inventory

    The HiPOx technology is an advanced oxidation process that incorporates high-precision delivery of ozone and hydrogen peroxide to chemically destroy organic contaminants with the promise of minimizing bromate formation. A MTBE-contaminated groundwater from the Ventura County Nav...

  2. DESTRUCTION OF PAHS AND PCBS IN WATER USING SULFATE RADICAL-BASED CATALYTIC ADVANCED OXIDATION PROCESSES

    EPA Science Inventory

    A new class of advanced oxidation processes (AOPs) based on sulfate radicals is being tested for the degradation of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in aqueous solution. These AOPs are based on the generation of sulfate radicals through...

  3. Advances in Understanding the Actions of Nitrous Oxide

    PubMed Central

    Emmanouil, Dimitris E; Quock, Raymond M

    2007-01-01

    Nitrous oxide (N2O) has been used for well over 150 years in clinical dentistry for its analgesic and anxiolytic properties. This small and simple inorganic chemical molecule has indisputable effects of analgesia, anxiolysis, and anesthesia that are of great clinical interest. Recent studies have helped to clarify the analgesic mechanisms of N2O, but the mechanisms involved in its anxiolytic and anesthetic actions remain less clear. Findings to date indicate that the analgesic effect of N2O is opioid in nature, and, like morphine, may involve a myriad of neuromodulators in the spinal cord. The anxiolytic effect of N2O, on the other hand, resembles that of benzodiazepines and may be initiated at selected subunits of the γ-aminobutyric acid type A (GABAA) receptor. Similarly, the anesthetic effect of N2O may involve actions at GABAA receptors and possibly at N-methyl-D-aspartate receptors as well. This article reviews the latest information on the proposed modes of action for these clinicaleffects of N2O. PMID:17352529

  4. Advanced oxide powders processing based on cascade plasma

    NASA Astrophysics Data System (ADS)

    Solonenko, O. P.; Smirnov, A. V.

    2014-11-01

    Analysis of the potential advantages offered to thermal spraying and powder processing by the implementation of plasma torches with inter-electrode insert (IEI) or, in other words, cascade plasma torches (CPTs) is presented. The paper provides evidence that the modular designed single cathode CPT helps eliminate the following major disadvantages of conventional plasma torches: plasma parameters drifting, 1-5 kHz pulsing of plasma flow, as well as excessive erosion of electrodes. More stable plasma results in higher quality, homogeneity and reproducibility of plasma sprayed coatings and powders treated. In addition, CPT offers an extremely wide operating window, which allows better control of plasma parameters, particle dwell time and, consequently, particle temperature and velocity within a wide range by generating high enthalpy quasi-laminar plasmas, medium enthalpy transient plasmas, as well as relatively low enthalpy turbulent plasmas. Stable operation, flexibility with plasma gases as well as wide operating window of CPT should help significantly improve the existing plasma spraying processes and coatings, and also help develop new advanced technologies.

  5. Hydrogen Peroxide Induced Protein Oxidation During Storage and Lyophilization Process.

    PubMed

    Cheng, Weiqiang; Zheng, Xiaoyang; Yang, Mark

    2016-06-01

    Although the impact of hydrogen peroxide (HP) on proteins in liquid solutions has been studied extensively, the impact during lyophilization has been largely overlooked. The purpose of this work was to investigate the effect of HP on lyophilized proteins and HP removal by lyophilization. A protein formulation at 5 mg/mL and its placebo were spiked with HP up to 5.0 ppm and then lyophilized. HP concentration, protein oxidation, and aggregation were monitored before and after lyophilization, as well as during storage at 25°C. The lyophilization process removed on average 94.1% of HP from protein formulation, but only 72.5% from the placebo. There were also significant increases in protein oxidization and aggregation. The oxidation increment correlated with the decrease of HP concentration in both the protein formulation and placebo at all temperatures. Protein oxidation at different freezing temperatures was also studied in follow-up studies. Data from these studies suggest that (1) HP has a significant impact on oxidation and aggregation of protein during lyophilization; (2) significant oxidation can occur even when the protein formulation is frozen; (3) the oxidized protein is more prone to aggregation during lyophilization process. PMID:27238482

  6. Iron(II) Initiation of Lipid and Protein Oxidation in Pork: The Role of Oxymyoglobin.

    PubMed

    Zhou, Feibai; Jongberg, Sisse; Zhao, Mouming; Sun, Weizheng; Skibsted, Leif H

    2016-06-01

    Iron(II), added as FeSO4·7H2O, was found to increase the rate of oxygen depletion as detected electrochemically in a pork homogenate from Longissimus dorsi through an initial increase in metmyoglobin formation from oxymyoglobin and followed by formation of primary and secondary lipid oxidation products and protein oxidation as detected as thiol depletion in myofibrillar proteins. Without added iron(II), under the same conditions at 37 °C, oxygen consumption corresponded solely to the slow oxymyoglobin autoxidation. Long-lived myofibrillar protein radicals as detected by ESR spectroscopy in the presence of iron(II) were formed subsequently to oxymyoglobin oxidation, and their level was increased by lipid oxidation when oxygen was completely depleted. Similarly, the time profile for formation of lipid peroxide indicated that oxymyoglobin oxidation initiates both protein oxidation and lipid oxidation. PMID:27217062

  7. Advanced materials for solid oxide fuel cells: Hafnium-Praseodymium-Indium Oxide System

    SciTech Connect

    Bates, J.L.; Griffin, C.W.; Weber, W.J.

    1988-06-01

    The HfO/sub 2/-PrO/sub 1.83/-In/sub 2/O/sub 3/ system has been studied at the Pacific Northwest Laboratory to develop alternative, highly electrically conducting oxides as electrode and interconnection materials for solid oxide fuel cells. A coprecipitation process was developed for synthesizing single-phase, mixed oxide powders necessary to fabricate powders and dense oxides. A ternary phase diagram was developed, and the phases and structures were related to electrical transport properties. Two new phases, an orthorhombic PrInO/sub 3/ and a rhombohedral Hf/sub 2/In/sub 2/O/sub 7/ phase, were identified. The highest electronic conductivity is related to the presence of a bcc, In/sub 2/O/sub 3/ solid solution (ss) containing HfO/sub 2/ and PrO/sub 1.83/. Compositions containing more than 35 mol % of the In/sub 2/O/sub 3/ ss have electrical conductivities greater than 10/sup /minus/1/ (ohm-cm)/sup /minus/1/, and the two or three phase structures that contain this phase appear to exhibit mixed electronic-ionic conduction. The high electrical conductivities and structures similar to the Y/sub 2/O/sub 3/-stabilized ZrO/sub 2/(HfO/sub 2/) electrolyte give these oxides potential for use as cathodes in solid oxide fuel cells. 21 refs.

  8. Mineralization of paracetamol in aqueous solution with advanced oxidation processes.

    PubMed

    Torun, Murat; Gültekin, Özge; Şolpan, Dilek; Güven, Olgun

    2015-01-01

    Paracetamol is a common analgesic drug widely used in all regions of the world more than hundred tonnes per year and it poses a great problem for the aquatic environment. Its phenolic intermediates are classified as persistent organic pollutants and toxic for the environment as well as human beings. In the present study, the irradiation of aqueous solutions of paracetamol with 60Co gamma-rays was examined on a laboratory scale and its degradation path was suggested with detected radiolysis products. The synergic effect of ozone on gamma-irradiation was investigated by preliminary ozonation before irradiation which reduced the irradiation dose from 5 to 3 kGy to completely remove paracetamol and its toxic intermediate hydroquinone from 6 to 4 kGy as well as increasing the radiation chemical yield (Gi values 1.36 and 1.66 in the absence and presence of ozone, respectively). The observed amount of formed hydroquinone was also decreased in the presence of ozone. There is a decrease in pH from 6.4 to 5.2 and dissolved oxygen consumed, which is up to 0.8 mg l(-1), to form some peroxyl radicals used for oxidation. Analytical measurements were carried out with gas chromatography/mass spectrometry and ion chromatography (IC) both qualitatively and quantitatively. Amounts of paracetamol and hydroquinone were measured with gas chromatography after trimethylsilane derivatization. Small aliphatic acids, such as acetic acid, formic acid and oxalic acid, were measured quantitatively with IC as well as inorganic ions (nitrite and nitrate) in which their yields increase with irradiation. PMID:25263253

  9. Advanced alternate planar geometry solid oxide fuel cells

    SciTech Connect

    Elangovan, S.; Prouse, D.; Khandkar, A.; Donelson, R.; Marianowski, L. )

    1992-11-01

    The potential of high temperature Solid Oxide Fuel Cells as high performance, high efficiency energy conversion device is well known. Investigation of several cell designs have been undertaken by various researchers to derive the maximum performance benefit from the device while maintaining a lower cost of production to meet the commercialization cost target. The present investigation focused on the planar SOFC design which allows for the use of mature low cost production processes to be employed. A novel design concept was investigated which allows for improvements in performance through increased interface stability, and lowering of cost through enhanced structural integrity and the use of low cost metal interconnects. The new cell design consisted of a co-sintered porous/dense/porous zirconia layer with the electrode material infiltrated into the porous layers. The two year program conducted by a team involving Ceramatec and the Institute of Gas Technology, culminated in a multi-cell stack test that exhibited high performance. Considerable progress was achieved in the selection of cell components, and establishing and optimizing the cell and stack fabrication parameters. It was shown that the stack components exhibited high conductivities and low creep at the operating temperature. The inter-cell resistive losses were shown to be small through out-of-cell characterization. The source of performance loss was identified to be the anode electrolyte interface. This loss however can be minimized by improving the anode infiltration technique. Manifolding and sealing of the planar devices posed considerable challenge. Even though the open circuit voltage was 250 mV/cell lower than theoretical, the two cell stack had a performance of 300 mA/cm[sup 2] at 0.4V/cell with an area specific resistance of 1 [Omega]-cm[sup 2]/cell. improvements in manifolding are expected to provide much higher performance.

  10. Advanced alternate planar geometry solid oxide fuel cells. Final report

    SciTech Connect

    Elangovan, S.; Prouse, D.; Khandkar, A.; Donelson, R.; Marianowski, L.

    1992-11-01

    The potential of high temperature Solid Oxide Fuel Cells as high performance, high efficiency energy conversion device is well known. Investigation of several cell designs have been undertaken by various researchers to derive the maximum performance benefit from the device while maintaining a lower cost of production to meet the commercialization cost target. The present investigation focused on the planar SOFC design which allows for the use of mature low cost production processes to be employed. A novel design concept was investigated which allows for improvements in performance through increased interface stability, and lowering of cost through enhanced structural integrity and the use of low cost metal interconnects. The new cell design consisted of a co-sintered porous/dense/porous zirconia layer with the electrode material infiltrated into the porous layers. The two year program conducted by a team involving Ceramatec and the Institute of Gas Technology, culminated in a multi-cell stack test that exhibited high performance. Considerable progress was achieved in the selection of cell components, and establishing and optimizing the cell and stack fabrication parameters. It was shown that the stack components exhibited high conductivities and low creep at the operating temperature. The inter-cell resistive losses were shown to be small through out-of-cell characterization. The source of performance loss was identified to be the anode electrolyte interface. This loss however can be minimized by improving the anode infiltration technique. Manifolding and sealing of the planar devices posed considerable challenge. Even though the open circuit voltage was 250 mV/cell lower than theoretical, the two cell stack had a performance of 300 mA/cm{sup 2} at 0.4V/cell with an area specific resistance of 1 {Omega}-cm{sup 2}/cell. improvements in manifolding are expected to provide much higher performance.

  11. Electrochemically Deposited Ceria Structures for Advanced Solid Oxide Fuel Cells

    NASA Astrophysics Data System (ADS)

    Brown, Evan C.

    As the pursuit towards emissions reduction intensifies with growing interest and nascent technologies, solid oxide fuel cells (SOFCs) remain an illustrious candidate for achieving our goals. Despite myriad advantages, SOFCs are still too costly for widespread deployment, even as unprecedented materials developments have recently emerged. This suggests that, in addition to informed materials selection, the necessary power output--and, thereby, cost-savings--gains must come from the fuel cell architecture. The work presented in this manuscript primarily investigates cathodic electrochemical deposition (CELD) as a scalable micro-/nanoscale fabrication tool for engineering ceria-based components in a SOFC assembly. Also, polymer sphere lithography was utilized to deposit fully connected, yet fully porous anti-dot metal films on yttira-stabilized zirconia (YSZ) with specific and knowable geometries, useful for mechanistic studies. Particular attention was given to anode structures, for which anti-dot metal films on YSZ served as composite substrates for subsequent CELD of doped ceria. By tuning the applied potential, a wide range of microstructures from high surface area coatings to planar, thin films was possible. In addition, definitive deposition was shown to occur on the electronically insulating YSZ surfaces, producing quality YSZ|ceria interfaces. These CELD ceria deposits exhibited promising electrochemical activity, as probed by A.C. Impedance Spectroscopy. In an effort to extend its usefulness as a SOFC fabrication tool, the CELD of ceria directly onto common SOFC cathode materials without a metallic phase was developed, as well as templated deposition schemes producing ceria nanowires and inverse opals.

  12. Nitric oxide-based protein modification: formation and site-specificity of protein S-nitrosylation

    PubMed Central

    Kovacs, Izabella; Lindermayr, Christian

    2013-01-01

    Nitric oxide (NO) is a reactive free radical with pleiotropic functions that participates in diverse biological processes in plants, such as germination, root development, stomatal closing, abiotic stress, and defense responses. It acts mainly through redox-based modification of cysteine residue(s) of target proteins, called protein S-nitrosylation.In this way NO regulates numerous cellular functions and signaling events in plants. Identification of S-nitrosylated substrates and their exact target cysteine residue(s) is very important to reveal the molecular mechanisms and regulatory roles of S-nitrosylation. In addition to the necessity of protein–protein interaction for trans-nitrosylation and denitrosylation reactions, the cellular redox environment and cysteine thiol micro-environment have been proposed important factors for the specificity of protein S-nitrosylation. Several methods have recently been developed for the proteomic identification of target proteins. However, the specificity of NO-based cysteine modification is still less defined. In this review, we discuss formation and specificity of S-nitrosylation. Special focus will be on potential S-nitrosylation motifs, site-specific proteomic analyses, computational predictions using different algorithms, and on structural analysis of cysteine S-nitrosylation. PMID:23717319

  13. Recombinant protein expression in Escherichia coli: advances and challenges

    PubMed Central

    Rosano, Germán L.; Ceccarelli, Eduardo A.

    2014-01-01

    Escherichia coli is one of the organisms of choice for the production of recombinant proteins. Its use as a cell factory is well-established and it has become the most popular expression platform. For this reason, there are many molecular tools and protocols at hand for the high-level production of heterologous proteins, such as a vast catalog of expression plasmids, a great number of engineered strains and many cultivation strategies. We review the different approaches for the synthesis of recombinant proteins in E. coli and discuss recent progress in this ever-growing field. PMID:24860555

  14. Nitric oxide (NO) in alleviation of heavy metal induced phytotoxicity and its role in protein nitration.

    PubMed

    Saxena, Ina; Shekhawat, G S

    2013-08-01

    Nitric oxide (NO) is recognized as a biological messenger in various tissues to regulate diverse range of physiological process including growth, development and response to abiotic and biotic factors. The NO emission from plants is known since the 1970s, and there is copious information on the multiple effects of exogenously applied NO on different physiological and biochemical processes of plants. Heavy metal toxicity is one of the major abiotic stresses leading to hazardous effects in plants and its toxicity is based on chemical and physical property. A common consequence of heavy metal toxicity is the uncontrolled and excessive accumulation of reactive oxygen species (ROS) which leads to peroxidation of lipids, oxidation of protein, inactivation of enzymes, DNA damage and/or interact with other vital constituents of plant cells. Recently, an increasing number of articles have reported the effects of exogenous NO on alleviating heavy metal toxicity in plants but knowledge of physiological mechanisms of NO in alleviating heavy metal toxicity is quite limited, and some results contradict one another. Therefore, to help clarify the roles of NO in heavy metal tolerance, it is important to review and discuss the recent advances on this area of research. NO can provoke both beneficial and harmful effects, which depend on the concentration and location of NO in the plant cells. NO alleviates the harmfulness of the ROS, and reacts with other target molecules, and regulates the expression of stress responsive genes under various stress conditions. This manuscript includes, the latest advances in understanding the effects of endogenous NO on heavy metal toxicity and the mechanisms and role of NO as an antioxidant as well as in protein nitration are highlighted. PMID:23545403

  15. Increased nitration and carbonylation of proteins in MRL +/+ mice exposed to trichloroethene: Potential role of protein oxidation in autoimmunity

    SciTech Connect

    Wang Gangduo; Wang Jianling; Ma Huaxian; Khan, M. Firoze

    2009-06-01

    Even though reactive oxygen and nitrogen species (RONS) are implicated as mediators of autoimmune diseases (ADs), little is known about contribution of protein oxidation (carbonylation and nitration) in the pathogenesis of such diseases. The focus of this study was, therefore, to establish a link between protein oxidation and induction and/or exacerbation of autoimmunity. To achieve this, female MRL +/+ mice were treated with trichloroethene (TCE), an environmental contaminant known to induce autoimmune response, for 6 or 12 weeks (10 mmol/kg, i.p., every 4{sup th} day). TCE treatment resulted in significantly increased formation of nitrotyrosine (NT) and induction of iNOS in the serum at both 6 and 12 weeks of treatment, but the response was greater at 12 weeks. Likewise, TCE treatment led to greater NT formation, and iNOS protein and mRNA expression in the livers and kidneys. Moreover, TCE treatment also caused significant increases ({approx}3 fold) in serum protein carbonyls (a marker of protein oxidation) at both 6 and 12 weeks. Significantly increased protein carbonyls were also observed in the livers and kidneys (2.1 and 1.3 fold, respectively) at 6 weeks, and to a greater extent at 12 weeks (3.5 and 2.1 fold, respectively) following TCE treatment. The increases in TCE-induced protein oxidation (carbonylation and nitration) were associated with significant increases in Th1 specific cytokine (IL-2, IFN-{gamma}) release into splenocyte cultures. These results suggest an association between protein oxidation and induction/exacerbation of autoimmune response. The results present a potential mechanism by which oxidatively modified proteins could contribute to TCE-induced autoimmune response and necessitates further investigations for clearly establishing the role of protein oxidation in the pathogenesis of ADs.

  16. Improved Identification and Relative Quantification of Sites of Peptide and Protein Oxidation for Hydroxyl Radical Footprinting

    NASA Astrophysics Data System (ADS)

    Li, Xiaoyan; Li, Zixuan; Xie, Boer; Sharp, Joshua S.

    2013-11-01

    Protein oxidation is typically associated with oxidative stress and aging and affects protein function in normal and pathological processes. Additionally, deliberate oxidative labeling is used to probe protein structure and protein-ligand interactions in hydroxyl radical protein footprinting (HRPF). Oxidation often occurs at multiple sites, leading to mixtures of oxidation isomers that differ only by the site of modification. We utilized sets of synthetic, isomeric "oxidized" peptides to test and compare the ability of electron-transfer dissociation (ETD) and collision-induced dissociation (CID), as well as nano-ultra high performance liquid chromatography (nanoUPLC) separation, to quantitate oxidation isomers with one oxidation at multiple adjacent sites in mixtures of peptides. Tandem mass spectrometry by ETD generates fragment ion ratios that accurately report on relative oxidative modification extent on specific sites, regardless of the charge state of the precursor ion. Conversely, CID was found to generate quantitative MS/MS product ions only at the higher precursor charge state. Oxidized isomers having multiple sites of oxidation in each of two peptide sequences in HRPF product of protein Robo-1 Ig1-2, a protein involved in nervous system axon guidance, were also identified and the oxidation extent at each residue was quantified by ETD without prior liquid chromatography (LC) separation. ETD has proven to be a reliable technique for simultaneous identification and relative quantification of a variety of functionally different oxidation isomers, and is a valuable tool for the study of oxidative stress, as well as for improving spatial resolution for HRPF studies.

  17. Heat Shock Proteins in Dermatophytes: Current Advances and Perspectives.

    PubMed

    Martinez-Rossi, Nilce M; Jacob, Tiago R; Sanches, Pablo R; Peres, Nalu T A; Lang, Elza A S; Martins, Maíra P; Rossi, Antonio

    2016-04-01

    Heat shock proteins (HSPs) are proteins whose transcription responds rapidly to temperature shifts. They constitute a family of molecular chaperones, involved in the proper folding and stabilisation of proteins under physiological and adverse conditions. HSPs also assist in the protection and recovery of cells exposed to a variety of stressful conditions, including heat. The role of HSPs extends beyond chaperoning proteins, as they also participate in diverse cellular functions, such as the assembly of macromolecular complexes, protein transport and sorting, dissociation of denatured protein aggregates, cell cycle control, and programmed cell death. They are also important antigens from a variety of pathogens, are able to stimulate innate immune cells, and are implicated in acquired immunity. In fungi, HSPs have been implicated in virulence, dimorphic transition, and drug resistance. Some HSPs are potential targets for therapeutic strategies. In this review, we discuss the current understanding of HSPs in dermatophytes, which are a group of keratinophilic fungi responsible for superficial mycoses in humans and animals. Computational analyses were performed to characterise the group of proteins in these dermatophytes, as well as to assess their conservation and to identify DNA-binding domains (5'-nGAAn-3') in the promoter regions of the hsp genes. In addition, the quantification of the transcript levels of few genes in a pacC background helped in the development of an extended model for the regulation of the expression of the hsp genes, which supports the participation of the pH-responsive transcriptional regulator PacC in this process. PMID:27226766

  18. Recent advances (2010-2015) in studies of cerium oxide nanoparticles' health effects.

    PubMed

    Li, Yan; Li, Peng; Yu, Hua; Bian, Ying

    2016-06-01

    Cerium oxide nanoparticles, widespread applied in our life, have attracted much concern for their human health effects. However, most of the works addressing cerium oxide nanoparticles toxicity have only used in vitro models or in vivo intratracheal instillation methods. The toxicity studies have varied results and not all are conclusive. The information about risk assessments derived from epidemiology studies is severely lacking. The knowledge of occupational safety and health (OSH) for exposed workers is very little. Thus this review focuses on recent advances in studies of toxicokinetics, antioxidant activity and toxicity. Additionally, aim to extend previous health effects assessments of cerium oxide nanoparticles, we summarize the epidemiology studies of engineered cerium oxide nanoparticles used as automotive diesel fuel additive, aerosol particulate matter in air pollution, other industrial ultrafine and nanoparticles (e.g., fumes particles generated in welding and flame cutting processes). PMID:27088851

  19. Rational design of metal oxide nanocomposite anodes for advanced lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Li, Yong; Yu, Shenglan; Yuan, Tianzhi; Yan, Mi; Jiang, Yinzhu

    2015-05-01

    Metal-oxide anodes represent a significant future direction for advanced lithium ion batteries. However, their practical applications are still seriously hampered by electrode disintegration and capacity fading during cycling. Here, we report a rational design of 3D-staggered metal-oxide nanocomposite electrode directly fabricated by pulsed spray evaporation chemical vapor deposition, where various oxide nanocomponents are in a staggered distribution uniformly along three dimensions and across the whole electrode. Such a special design of nanoarchitecture combines the advantages of nanoscale materials in volume change and Li+/electron conduction as well as uniformly staggered and compact structure in atom migration during lithiation/delithiation, which exhibits high specific capacity, good cycling stability and excellent rate capability. The rational design of metal-oxide nanocomposite electrode opens up new possibilities for high performance lithium ion batteries.

  20. Oxygen Penalty for Waste Oxidation in an Advanced Life Support System: A Systems Approach

    NASA Technical Reports Server (NTRS)

    Pisharody, Suresh; Wignarajah, K.; Fisher, John

    2002-01-01

    Oxidation is one of a number of technologies that are being considered for waste management and resource recovery from waste materials generated on board space missions. Oxidation processes are a very effective and efficient means of clean and complete conversion of waste materials to sterile products. However, because oxidation uses oxygen there is an "oxygen penalty" associated either with resupply of oxygen or with recycling oxygen from some other source. This paper is a systems approach to the issue of oxygen penalty in life support systems and presents findings on the oxygen penalty associated with an integrated oxidation-Sabatier-Oxygen Generation System (OGS) for waste management in an Advanced Life Support System. The findings reveal that such an integrated system can be operated to form a variety of useful products without a significant oxygen penalty.

  1. Application of UV based advanced oxidation to treat sulfolane in an aqueous medium.

    PubMed

    Yu, Linlong; Mehrabani-Zeinabad, Mitra; Achari, Gopal; Langford, Cooper H

    2016-10-01

    Several oxidative methods were studied to degrade sulfolane in an aqueous medium. These include UVA and UVC irradiation with suitable photoactive oxidants, including ozone, H2O2, and TiO2 based photocatalysis and their combinations. Since sulfolane lacks absorption bands in the UV range beyond 200 nm, initiation of reactions depends on the spectra and photochemistry of the oxidants. Among all the advanced oxidation processes investigated, combinations of (a) UVC with H2O2 and O3 (b) UVC with H2O2 and (c) UVC with O3 led to the highest rate of sulfolane loss in synthetic water samples. Experiments on sulfolane contaminated groundwater samples also indicated that these three combinations can efficiently degrade sulfolane. Furthermore, a synergistic effect was observed in the combination of H2O2 and O3 photolysis. PMID:27372265

  2. Recent advances in recombinant protein-based malaria vaccines.

    PubMed

    Draper, Simon J; Angov, Evelina; Horii, Toshihiro; Miller, Louis H; Srinivasan, Prakash; Theisen, Michael; Biswas, Sumi

    2015-12-22

    Plasmodium parasites are the causative agent of human malaria, and the development of a highly effective vaccine against infection, disease and transmission remains a key priority. It is widely established that multiple stages of the parasite's complex lifecycle within the human host and mosquito vector are susceptible to vaccine-induced antibodies. The mainstay approach to antibody induction by subunit vaccination has been the delivery of protein antigen formulated in adjuvant. Extensive efforts have been made in this endeavor with respect to malaria vaccine development, especially with regard to target antigen discovery, protein expression platforms, adjuvant testing, and development of soluble and virus-like particle (VLP) delivery platforms. The breadth of approaches to protein-based vaccines is continuing to expand as innovative new concepts in next-generation subunit design are explored, with the prospects for the development of a highly effective multi-component/multi-stage/multi-antigen formulation seeming ever more likely. This review will focus on recent progress in protein vaccine design, development and/or clinical testing for a number of leading malaria antigens from the sporozoite-, merozoite- and sexual-stages of the parasite's lifecycle-including PfCelTOS, PfMSP1, PfAMA1, PfRH5, PfSERA5, PfGLURP, PfMSP3, Pfs48/45 and Pfs25. Future prospects and challenges for the development, production, human delivery and assessment of protein-based malaria vaccines are discussed. PMID:26458807

  3. Recent advances in recombinant protein-based malaria vaccines

    PubMed Central

    Draper, Simon J.; Angov, Evelina; Horii, Toshihiro; Miller, Louis H.; Srinivasan, Prakash; Theisen, Michael; Biswas, Sumi

    2015-01-01

    Plasmodium parasites are the causative agent of human malaria, and the development of a highly effective vaccine against infection, disease and transmission remains a key priority. It is widely established that multiple stages of the parasite's complex lifecycle within the human host and mosquito vector are susceptible to vaccine-induced antibodies. The mainstay approach to antibody induction by subunit vaccination has been the delivery of protein antigen formulated in adjuvant. Extensive efforts have been made in this endeavor with respect to malaria vaccine development, especially with regard to target antigen discovery, protein expression platforms, adjuvant testing, and development of soluble and virus-like particle (VLP) delivery platforms. The breadth of approaches to protein-based vaccines is continuing to expand as innovative new concepts in next-generation subunit design are explored, with the prospects for the development of a highly effective multi-component/multi-stage/multi-antigen formulation seeming ever more likely. This review will focus on recent progress in protein vaccine design, development and/or clinical testing for a number of leading malaria antigens from the sporozoite-, merozoite- and sexual-stages of the parasite's lifecycle–including PfCelTOS, PfMSP1, PfAMA1, PfRH5, PfSERA5, PfGLURP, PfMSP3, Pfs48/45 and Pfs25. Future prospects and challenges for the development, production, human delivery and assessment of protein-based malaria vaccines are discussed. PMID:26458807

  4. Advanced oxidation-resistant iron-based alloys for LWR fuel cladding

    NASA Astrophysics Data System (ADS)

    Terrani, K. A.; Zinkle, S. J.; Snead, L. L.

    2014-05-01

    Application of advanced oxidation-resistant iron alloys as light water reactor fuel cladding is proposed. The motivations are based on specific limitations associated with zirconium alloys, currently used as fuel cladding, under design-basis and beyond-design-basis accident scenarios. Using a simplified methodology, gains in safety margins under severe accidents upon transition to advanced oxidation-resistant iron alloys as fuel cladding are showcased. Oxidation behavior, mechanical properties, and irradiation effects of advanced iron alloys are briefly reviewed and compared to zirconium alloys as well as historic austenitic stainless steel cladding materials. Neutronic characteristics of iron-alloy-clad fuel bundles are determined and fed into a simple economic model to estimate the impact on nuclear electricity production cost. Prior experience with steel cladding is combined with the current understanding of the mechanical properties and irradiation behavior of advanced iron alloys to identify a combination of cladding thickness reduction and fuel enrichment increase (∼0.5%) as an efficient route to offset any penalties in cycle length, due to higher neutron absorption in the iron alloy cladding, with modest impact on the economics.

  5. Advanced oxidation for indirect potable reuse: a practical application in Australia.

    PubMed

    Poussade, Y; Roux, A; Walker, T; Zavlanos, V

    2009-01-01

    December 2008 marked the completion of Stage 2B of the Western Corridor Recycled Water (WCRW) Project in South East Queensland, Australia. With a maximum combined production capacity of 232 million litres of purified recycled water a day, it is the third largest recycled water scheme in the world and the largest in southern hemisphere. A seven-barrier approach has been used to ensure very highest quality, safe water is produced at all times for the purpose of indirect potable reuse. Three of these barriers occur in the advanced water treatment section of the WCRW Project: micro- or ultra-filtration (MF), reverse osmosis (RO), and H(2)O(2)/UV advanced oxidation. In addition to providing very efficient disinfection, the advanced oxidation process specifically aims at destroying compounds not fully rejected by RO that are potential health hazards. This includes N-nitrosodimethylamine (NDMA), which is a potential carcinogenic product likely to be formed by chlorination or chloramination of wastewaters. As in many other countries, Australia has adopted a stringent guideline limit for this compound of 10 ng/L in purified recycled water. After 16 months of operations of the WCRW Project's first plant, the advanced oxidation system has been proven effective in removing NDMA and ensuring 100% compliance with the regulation at a controlled cost. PMID:19901475

  6. Recent advances in large-scale protein interactome mapping.

    PubMed

    Mehta, Virja; Trinkle-Mulcahy, Laura

    2016-01-01

    Protein-protein interactions (PPIs) underlie most, if not all, cellular functions. The comprehensive mapping of these complex networks of stable and transient associations thus remains a key goal, both for systems biology-based initiatives (where it can be combined with other 'omics' data to gain a better understanding of functional pathways and networks) and for focused biological studies. Despite the significant challenges of such an undertaking, major strides have been made over the past few years. They include improvements in the computation prediction of PPIs and the literature curation of low-throughput studies of specific protein complexes, but also an increase in the deposition of high-quality data from non-biased high-throughput experimental PPI mapping strategies into publicly available databases. PMID:27158474

  7. Recent advances in large-scale protein interactome mapping

    PubMed Central

    Mehta, Virja; Trinkle-Mulcahy, Laura

    2016-01-01

    Protein-protein interactions (PPIs) underlie most, if not all, cellular functions. The comprehensive mapping of these complex networks of stable and transient associations thus remains a key goal, both for systems biology-based initiatives (where it can be combined with other ‘omics’ data to gain a better understanding of functional pathways and networks) and for focused biological studies. Despite the significant challenges of such an undertaking, major strides have been made over the past few years. They include improvements in the computation prediction of PPIs and the literature curation of low-throughput studies of specific protein complexes, but also an increase in the deposition of high-quality data from non-biased high-throughput experimental PPI mapping strategies into publicly available databases. PMID:27158474

  8. NOSTRIN: A protein modulating nitric oxide release and subcellular distribution of endothelial nitric oxide synthase

    PubMed Central

    Zimmermann, Kirstin; Opitz, Nils; Dedio, Jürgen; Renné, Christoph; Müller-Esterl, Werner; Oess, Stefanie

    2002-01-01

    Activity and localization of endothelial nitric oxide synthase (eNOS) is regulated in a remarkably complex fashion, yet the complex molecular machinery mastering stimulus-induced eNOS translocation and trafficking is poorly understood. In a search by the yeast two-hybrid system using the eNOS oxygenase domain as bait, we have identified a previously uncharacterized eNOS-interacting protein, dubbed NOSTRIN (for eNOS traffic inducer). NOSTRIN contains a single polypeptide chain of 506-aa residues of 58 kDa with an N-terminal cdc15 domain and a C-terminal SH3 domain. NOSTRIN mRNA is abundant in highly vascularized tissues such as placenta, kidney, lung, and heart, and NOSTRIN protein is expressed in vascular endothelial cells. Coimmunoprecipitation experiments demonstrated the eNOS–NOSTRIN interaction in vitro and in vivo, and NOSTRIN's SH3 domain was essential and sufficient for eNOS binding. NOSTRIN colocalized extensively with eNOS at the plasma membrane of confluent human umbilical venous endothelial cells and in punctate cytosolic structures of CHO-eNOS cells. NOSTRIN overexpression induced a profound redistribution of eNOS from the plasma membrane to vesicle-like structures matching the NOSTRIN pattern and at the same time led to a significant inhibition of NO release. We conclude that NOSTRIN contributes to the intricate protein network controlling activity, trafficking, and targeting of eNOS. PMID:12446846

  9. Biological efficacy and toxic effect of emergency water disinfection process based on advanced oxidation technology.

    PubMed

    Tian, Yiping; Yuan, Xiaoli; Xu, Shujing; Li, Rihong; Zhou, Xinying; Zhang, Zhitao

    2015-12-01

    An innovative and removable water treatment system consisted of strong electric field discharge and hydrodynamic cavitation based on advanced oxidation technologies was developed for reactive free radicals producing and waterborne pathogens eliminating in the present study. The biological efficacy and toxic effects of this advanced oxidation system were evaluated during water disinfection treatments. Bench tests were carried out with synthetic microbial-contaminated water, as well as source water in rainy season from a reservoir of Dalian city (Liaoning Province, China). Results showed that high inactivation efficiency of Escherichia coli (>5 log) could be obtained for synthetic contaminated water at a low concentration (0.5-0.7 mg L(-1)) of total oxidants in 3-10 s. The numbers of wild total bacteria (108 × 10(3) CFU mL(-1)) and total coliforms (260 × 10(2) MPN 100 mL(-1)) in source water greatly reduced to 50 and 0 CFU mL(-1) respectively after treated by the advanced oxidation system, which meet the microbiological standards of drinking water, and especially that the inactivation efficiency of total coliforms could reach 100%. Meanwhile, source water qualities were greatly improved during the disinfection processes. The values of UV254 in particular were significantly reduced (60-80%) by reactive free radicals. Moreover, the concentrations of possible disinfection by-products (formaldehyde and bromide) in treated water were lower than detection limits, indicating that there was no harmful effect on water after the treatments. These investigations are helpful for the ecotoxicological studies of advanced oxidation system in the treatments of chemical polluted water or waste water. The findings of this work suggest that the developed water treatment system is ideal in the acute phases of emergencies, which also could offer additional advantages over a wide range of applications in water pollution control. PMID:26427371

  10. Effect of green tea or rosemary extract on protein oxidation in Bologna type sausages prepared from oxidatively stressed pork.

    PubMed

    Jongberg, Sisse; Tørngren, Mari Ann; Gunvig, Annemarie; Skibsted, Leif H; Lund, Marianne N

    2013-03-01

    Bologna type sausages were prepared from oxidatively stressed pork (UV-irradiation, 48 h, 5 °C) using a traditional recipe (control) or the same recipe but added green tea extract (500 ppm total phenolic compounds) or rosemary extract (400 ppm total phenolic compounds). Green tea and rosemary extracts protected against formation of TBARS and protein carbonyls. On the contrary, increased thiol loss and a distinct loss of myosin heavy chain and actin due to polymerization by reducible bonds as determined by SDS-page were found by addition of green tea extract. The enhanced protein polymerization was ascribed to the reaction between quinone compounds from the plant extracts and protein thiol groups to yield phenol-mediated protein polymerization. Analysis by ESR spectroscopy revealed increased radical intensities in sausages added plant extracts, which was ascribed to originate from protein-bound phenoxyl radicals, which may protect against other oxidatively induced protein modifications. PMID:23273462

  11. Pharmacokinetics and toxicology of therapeutic proteins: Advances and challenges

    PubMed Central

    Vugmeyster, Yulia; Xu, Xin; Theil, Frank-Peter; Khawli, Leslie A; Leach, Michael W

    2012-01-01

    Significant progress has been made in understanding pharmacokinetics (PK), pharmacodynamics (PD), as well as toxicity profiles of therapeutic proteins in animals and humans, which have been in commercial development for more than three decades. However, in the PK arena, many fundamental questions remain to be resolved. Investigative and bioanalytical tools need to be established to improve the translation of PK data from animals to humans, and from in vitro assays to in vivo readouts, which would ultimately lead to a higher success rate in drug development. In toxicology, it is known, in general, what studies are needed to safely develop therapeutic proteins, and what studies do not provide relevant information. One of the major complicating factors in nonclinical and clinical programs for therapeutic proteins is the impact of immunogenicity. In this review, we will highlight the emerging science and technology, as well as the challenges around the pharmacokinetic- and safety-related issues in drug development of mAbs and other therapeutic proteins. PMID:22558487

  12. Efficient removal of insecticide "imidacloprid" from water by electrochemical advanced oxidation processes.

    PubMed

    Turabik, Meral; Oturan, Nihal; Gözmen, Belgin; Oturan, Mehmet A

    2014-01-01

    The oxidative degradation of imidacloprid (ICP) has been carried out by electrochemical advanced oxidation processes (EAOPs), anodic oxidation, and electro-Fenton, in which hydroxyl radicals are generated electrocatalytically. Carbon-felt cathode and platinum or boron-doped diamond (BDD) anodes were used in electrolysis cell. To determine optimum operating conditions, the effects of applied current and catalyst concentration were investigated. The decay of ICP during the oxidative degradation was well fitted to pseudo-first-order reaction kinetics and absolute rate constant of the oxidation of ICP by hydroxyl radicals was found to be k abs(ICP) = 1.23 × 10(9) L mol(-1) s(-1). The results showed that both anodic oxidation and electro-Fenton process with BDD anode exhibited high mineralization efficiency reaching 91 and 94% total organic carbon (TOC) removal at 2 h, respectively. For Pt-EF process, mineralization efficiency was also obtained as 71%. The degradation products of ICP were identified and a plausible general oxidation mechanism was proposed. Some of the main reaction intermediates such as 6-chloronicotinic acid, 6-chloronicotinaldehyde, and 6-hydroxynicotinic acid were determined by GC-MS analysis. Before complete mineralization, formic, acetic, oxalic, and glyoxylic acids were identified as end-products. The initial chlorine and organic nitrogen present in ICP were found to be converted to inorganic anions Cl(-), NO₃(-), and NH₄(+). PMID:24671401

  13. Advanced Multi-Component Defect Cluster Oxide Doped Zirconia-Yttria Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.

    1990-01-01

    The advantages of using ceramic thermal barrier coatings in gas turbine engine hot sections include increased fuel efficiency and improved engine reliability. However, current thermal barrier coatings will not have the low thermal conductivity and necessary sintering resistance under higher operating temperatures and thermal gradients required by future advanced ultra-efficient and low-emission aircraft engines. In this paper, a novel oxide defect cluster design approach is described for achieving low thermal conductivity and excellent thermal stability of the thermal barrier coating systems. This approach utilizes multi-component rare earth and other metal cluster oxide dopants that are incorporated in the zirconia-yttria based systems, thus significantly reducing coating thermal conductivity and sintering resistance by effectively promoting the formation of thermodynamically stable, essentially immobile defect clusters and/or nanoscale phases. The performance of selected plasma-sprayed cluster oxide thermal barrier coating systems has been evaluated. The advanced multi-component thermal barrier coating systems were found to have significantly lower initial and long-term thermal conductivities, and better high temperature stability. The effect of oxide cluster dopants on coating thermal conductivity, sintering resistance, oxide grain growth behavior and durability will be discussed.

  14. Advanced Multi-Component Defect Cluster Oxide Doped Zirconia-Yttria Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.

    2003-01-01

    The advantages of using ceramic thermal barrier coatings in gas turbine engine hot sections include increased fuel efficiency and improved engine reliability. However, current thermal barrier coatings will not have the low thermal conductivity and necessary sintering resistance under higher operating temperatures and thermal gradients required by future advanced ultra efficient and low emission aircraft engines. In this paper, a novel oxide defect cluster design approach is described for achieving low thermal conductivity and excellent thermal stability of the thermal barrier coating systems. This approach utilizes multi-component rare earth and other metal cluster oxide dopants that are incorporated in the zirconia-yttna based systems, thus significantly reducing coating thermal conductivity and sintering resistance by effectively promoting the formation of thermodynamically stable, essentially immobile defect clusters and/or nanoscale phases. The performance of selected plasma-sprayed cluster oxide thermal barrier coating systems has been evaluated. The advanced multi-component thermal barrier coating systems were found to have significantly lower initial and long-term thermal conductivities, and better high temperature stability. The effect of oxide cluster dopants on coating thermal conductivity, sintering resistance, oxide grain growth behavior and durability will be discussed.

  15. Identification of transformation products during advanced oxidation of diatrizoate: Effect of water matrix and oxidation process.

    PubMed

    Azerrad, Sara P; Lütke Eversloh, Christian; Gilboa, Maayan; Schulz, Manoj; Ternes, Thomas; Dosoretz, Carlos G

    2016-10-15

    Removal of micropollutants from reverse osmosis (RO) brines of wastewater desalination by oxidation processes is influenced by the scavenging capacity of brines components, resulting in the accumulation of transformation products (TPs) rather than complete mineralization. In this work the iodinated contrast media diatrizoate (DTZ) was used as model compound due to its relative resistance to oxidation. Identification of TPs was performed in ultrapure water (UPW) and RO brines applying nonthermal plasma (NTP) and UVA-TiO2 as oxidation techniques. The influence of main RO brines components in the formation and accumulation of TPs, such as chloride, bicarbonate alkalinity and humic acid, was also studied during UVA-TiO2. DTZ oxidation pattern in UPW resulted similar in both UVA-TiO2 and NTP achieving 66 and 61% transformation, respectively. However, DTZ transformation in RO brines was markedly lower in UVA-TiO2 (9%) than in NTP (27%). These differences can be attributed to the synergic effect of RO brines components during NTP. Moreover, reactive species other than hydroxyl radical contributed to DTZ transformation, i.e., direct photolysis in UVA-TiO2 and direct photolysis + O3 in NTP accounted for 16 and 23%, respectively. DTZ transformation led to iodide formation in both oxidation techniques but it further oxidized to iodate by ozone in NTP. In total 14 transformation products were identified in UPW of which 3 were present only in UVA-TiO2 and 2 were present exclusively in NTP; 5 of the 14 TPs were absent in RO brines. Five of them were new and were denoted as TP-474A/B, TP-522, TP-586, TP-602, TP-628. TP-522 (mono-chlorinated) was elucidated only in presence of high chloride titer-synthetic water matrix in NTP, most probably formed by active chlorine species generated in situ. TPs accumulation in RO brines was markedly different in comparison to UPW. This denotes the influence of RO brines components in the formation of reactive species that could further attack

  16. Influence of sodium nitrite on protein oxidation and nitrosation of sausages subjected to processing and storage.

    PubMed

    Feng, Xianchao; Li, Chenyi; Jia, Xu; Guo, Yan; Lei, Na; Hackman, Robert M; Chen, Lin; Zhou, Guanghong

    2016-06-01

    The influence of NaNO2 content on protein oxidation and nitrosation was investigated in cooked sausages at different concentrations (0, 50, 100, 200 and 400mg NaNO2/kg). Dependent on concentration, NaNO2 had both anti- and pro-oxidant effects on protein oxidation. The antioxidant effects of NaNO2 on the protein oxidation were evidenced by significantly lower carbonyl contents, higher free amines and lower surface hydrophobicities. The pro-oxidant effects of NaNO2 on protein oxidation resulted in a decrease of sulfhydryls and an increase of disulfide bonds. NaNO2 also improved the protein nitrosation inducing the formation of 3-nitrotyrosine (3-NT). Moreover, 3-NT had significant correlations with parameters of protein oxidation, indicating that 3-NT may be a possible marker for protein oxidation. Results of this study contribute to an understanding of the impact of NaNO2 on food quality and help to identify optimal formulations of cured meat products. PMID:26923991

  17. The study of leachate treatment by using three advanced oxidation process based wet air oxidation

    PubMed Central

    2013-01-01

    Wet air oxidation is regarded as appropriate options for wastewater treatment with average organic compounds. The general purpose of this research is to determine the efficiency of three wet air oxidation methods, wet oxidation with hydrogen peroxide and absorption with activated carbon in removing organic matter and nitrogenous compounds from Isfahan's urban leachate. A leachate sample with the volume of 1.5 liters entered into a steel reactor with the volume of three liters and was put under a 10-bar pressure, at temperatures of 100, 200, and 300° as well as three retention times of 30, 60, and 90 minutes. The sample was placed at 18 stages of leachate storage ponds in Isfahan Compost Plant with the volume of 20 liters, using three WPO, WAO methods and a combination of WAO/GAC for leachate pre-treatment. Thirty percent of pure oxygen and hydrogen peroxide were applied as oxidation agents. The COD removal efficiency in WAO method is 7.8-33.3%, in BOD is 14.7-50.6%, the maximum removal percentage (efficiency) for NH4-N is 53.3% and for NO3-N is 56.4-73.9%. The removal efficiency of COD and BOD5 is 4.6%-34 and 24%-50 respectively in WPO method. Adding GAC to the reactor, the removal efficiency of all parameters was improved. The maximum removal efficiency was increased 48% for COD, 31%-43.6 for BOD5 by a combinational method, and the ratio of BOD5/COD was also increased to 90%. In this paper, WAO and WPO process was used for Leachate pre-treatment and WAO/GAC combinational process was applied for improving the organic matter removal and leachate treatment; it was also determined that the recent process is much more efficient in removing resistant organic matter. PMID:23369258

  18. Reverse phase protein microarrays advance to use in clinical trials.

    PubMed

    Mueller, Claudius; Liotta, Lance A; Espina, Virginia

    2010-12-01

    Individualizing cancer therapy for molecular targeted inhibitors requires a new class of molecular profiling technology that can map the functional state of the cancer cell signal pathways containing the drug targets. Reverse phase protein microarrays (RPMA) are a technology platform designed for quantitative, multiplexed analysis of specific phosphorylated, cleaved, or total (phosphorylated and non-phosphorylated) forms of cellular proteins from a limited amount of sample. This class of microarray can be used to interrogate tissue samples, cells, serum, or body fluids. RPMA were previously a research tool; now this technology has graduated to use in research clinical trials with clinical grade sensitivity and precision. In this review we describe the application of RPMA for multiplexed signal pathway analysis in therapeutic monitoring, biomarker discovery, and evaluation of pharmaceutical targets, and conclude with a summary of the technical aspects of RPMA construction and analysis. PMID:20974554

  19. Advances in protein-amino acid nutrition of poultry.

    PubMed

    Baker, David H

    2009-05-01

    The ideal protein concept has allowed progress in defining requirements as well as the limiting order of amino acids in corn, soybean meal, and a corn-soybean meal mixture for growth of young chicks. Recent evidence suggests that glycine (or serine) is a key limiting amino acid in reduced protein [23% crude protein (CP) reduced to 16% CP] corn-soybean meal diets for broiler chicks. Research with sulfur amino acids has revealed that small excesses of cysteine are growth depressing in chicks fed methionine-deficient diets. Moreover, high ratios of cysteine:methionine impair utilization of the hydroxy analog of methionine, but not of methionine itself. A high level of dietary L: -cysteine (2.5% or higher) is lethal for young chicks, but a similar level of DL: -methionine, L: -cystine or N-acetyl-L: -cysteine causes no mortality. A supplemental dietary level of 3.0% L: -cysteine (7x requirement) causes acute metabolic acidosis that is characterized by a striking increase in plasma sulfate and decrease in plasma bicarbonate. S-Methylmethionine, an analog of S-adenosylmethionine, has been shown to have choline-sparing activity, but it only spares methionine when diets are deficient in choline and(or) betaine. Creatine, or its precursor guanidinoacetic acid, can spare dietary arginine in chicks. PMID:19009229

  20. Plasma oxidative stress biomarkers, nitric oxide and heat shock protein 70 in trained elite soccer players.

    PubMed

    Banfi, G; Malavazos, A; Iorio, E; Dolci, A; Doneda, L; Verna, R; Corsi, M M

    2006-03-01

    The physiological response to the physical exercise involves a number of changes in the oxidative balance and in the metabolism of some important biological molecules, including nitric oxide (NO) and heat shock proteins (Hsp 70). With the aim to optimise previous laboratory diagnostic panels, we measured the plasma concentration of reactive oxygen metabolites (ROMs), total antioxidant status (TAS), glutathione reductase (GR) activity, and NO and Hsp 70 levels in 44 elite, antioxidant-supplemented and trained soccer players and in 15 sedentary controls. Although no statistically significant difference between athletes and controls was detected in the plasma level of ROMs and TAS, soccer players showed a significantly higher plasma GR activity, NO and Hst 70 levels than those of sedentary controls. These findings suggest that the measuring of relatively novel biomarkers in sport medicine, like GR, NO and Hsp 70, in addition to the well-known and reliable assays (d-ROMs test and TAS) may be useful to a clinician to better assess and evaluate the benefits of training and/or supplementation programs. PMID:16344941

  1. Review of photochemical reaction constants of organic micropollutants required for UV advanced oxidation processes in water.

    PubMed

    Wols, B A; Hofman-Caris, C H M

    2012-06-01

    Emerging organic contaminants (pharmaceutical compounds, personal care products, pesticides, hormones, surfactants, fire retardants, fuel additives etc.) are increasingly found in water sources and therefore need to be controlled by water treatment technology. UV advanced oxidation technologies are often used as an effective barrier against organic contaminants. The combined operation of direct photolysis and reaction with hydroxyl radicals ensures good results for a wide range of contaminants. In this review, an overview is provided of the photochemical reaction parameters (quantum yield, molar absorption, OH radical reaction rate constant) of more than 100 organic micropollutants. These parameters allow for a prediction of organic contaminant removal by UV advanced oxidation systems. An example of contaminant degradation is elaborated for a simplified UV/H(2)O(2) system. PMID:22483836

  2. Advanced Catalysts for the Ambient Temperature Oxidation of Carbon Monoxide and Formaldehyde

    NASA Technical Reports Server (NTRS)

    Nalette, Tim; Eldridge, Christopher; Yu, Ping; Alpetkin, Gokhan; Graf, John

    2010-01-01

    The primary applications for ambient temperature carbon monoxide (CO) oxidation catalysts include emergency breathing masks and confined volume life support systems, such as those employed on the Shuttle. While Hopcalite is typically used in emergency breathing masks for terrestrial applications, in the 1970s, NASA selected a 2% platinum (Pt) on carbon for use on the Shuttle since it is more active and also more tolerant to water vapor. In the last 10-15 years there have been significant advances in ambient temperature CO oxidation catalysts. Langley Research Center developed a monolithic catalyst for ambient temperature CO oxidation operating under stoichiometric conditions for closed loop carbon dioxide (CO2) laser applications which is also advertised as having the potential to oxidize formaldehyde (HCHO) at ambient temperatures. In the last decade it has been discovered that appropriate sized nano-particles of gold are highly active for CO oxidation, even at sub-ambient temperatures, and as a result there has been a wealth of data reported in the literature relating to ambient/low temperature CO oxidation. In the shorter term missions where CO concentrations are typically controlled via ambient temperature oxidation catalysts, formaldehyde is also a contaminant of concern, and requires specially treated carbons such as Calgon Formasorb as untreated activated carbon has effectively no HCHO capacity. This paper examines the activity of some of the newer ambient temperature CO and formaldehyde (HCHO) oxidation catalysts, and measures the performance of the catalysts relative to the NASA baseline Ambient Temperature Catalytic Oxidizer (ATCO) catalyst at conditions of interest for closed loop trace contaminant control systems.

  3. Advanced oxidation processes for degradation of 2,4-dichlo- and 2,4-dimethylphenol

    SciTech Connect

    Trapido, M.; Veressinina, Y.; Munter, R.

    1998-08-01

    The efficiency of different advanced oxidation processes for degradation of two phenols, 2,4-dimethylphenol (2,4-DMP) and 2,4-dichlorophenol (2,4-DCP), has been under study. Advanced oxidation processes, especially the Fe{sup 2+}/H{sub 2}O{sub 2}/ultraviolet (UV) system, were found to be effective in decomposing phenols and chlorophenols. The degradation rate for 2,4-DCP followed the order, H{sub 2}O{sub 2}/Fe{sup 2+}/UV > H{sub 2}O{sub 2}/Fe{sup 2+} > O{sub 3}/ultrasound (US) > O{sub 3} {ge} O{sub 3}/UV > UV/H{sub 2}O{sub 2} {ge} US > UV. The corresponding order for 2,4-DMP was H{sub 2}O{sub 2}/Fe{sup 2+}/UV > O{sub 3}/US > O{sub 3} {ge} O{sub 3}/UV > H{sub 2}O{sub 2}/Fe{sup 2+} > US {ge} UV/H{sub 2}O{sub 2} > UV. Therefore, the chemical treatment, especially advanced oxidation processes, may be an alternative method for destruction of phenols and purification of wastewaters containing phenolic compounds.

  4. Oxidation behavior of plasma sintered beryllium-titanium intermetallic compounds as an advanced neutron multiplier

    NASA Astrophysics Data System (ADS)

    Kim, Jae-Hwan; Nakamichi, Masaru

    2013-07-01

    Beryllium intermetallic compounds (beryllides) such as Be12Ti are very promising candidates for advanced neutron multiplier materials in a demonstration fusion power reactor (DEMO). However, beryllides are too brittle to be fabricated either into pebble-type or rod-type shapes via conventional methods (i.e. arc melting and hot isostatic pressing). We have proposed a plasma sintering technique as a new method for beryllide fabrication, and our studies on the properties of plasma sintered beryllides are ongoing. In the present work, the oxidation properties of plasma sintered beryllides were investigated at 1273 K for 24 h in a dry air atmosphere to evaluate the high temperature properties of this material. Thermal gravimetry measurements indicate that specimens with larger fractions of Be12Ti phase corresponding to samples that have been sintered for longer time periods, exhibit superior oxidation properties. Our evaluation of the oxidation behavior of each phase in our beryllide samples is as follows: Be12Ti and Be17Ti2 both have good oxidation resistance, owing to the formation of dense and protective scales, while the Be and Be2Ti phases are mainly responsible for thermal-gravimetry (TG) weight gains, which is indicative of severe oxidation. We attribute the degradation in oxidation resistance specifically to Be2Ti that transforms into TiO2, and also find this phase to be the cause of deterioration in the mechanical properties of samples, owing to cracks near Be2Ti phase conglomerates.

  5. Soil remediation by an advanced oxidative method assisted with ultrasonic energy.

    PubMed

    Flores, Roberto; Blass, Georgina; Domínguez, Vanessa

    2007-02-01

    A new process for the remediation of soil contaminated with hydrocarbons is proposed. The innovation consists on coupling an advanced oxidative method, using a Fenton-type catalyst, with the application of ultrasonic energy. The use of ultrasonic energy not only assists the desorption of the contaminants from the soil, but also promotes the formation of OH radicals, which are the oxidant agents involved in the oxidation process. Different Fenton-like catalysts were employed in the present study; however, the highest removal of toluene and xylenes were obtained with iron sulfate and copper sulfate, respectively. Also, hydrogen peroxide was tested at different concentrations, and it was found that increasing its concentration enhanced the removal of all the contaminants. Finally, it was demonstrated that applying ultrasonic energy to the reacting system process noticeably enhanced the global efficiency of the process due to a synergistic effect in conjunction with the hydrogen peroxide concentration and type of catalyst. PMID:17079076

  6. Advanced Oxide Material Systems for 1650 C Thermal/Environmental Barrier Coating Applications

    NASA Technical Reports Server (NTRS)

    Zhu, Dong-Ming; Fox, Dennis S.; Bansal, Narottam P.; Miller, Robert A.

    2004-01-01

    Advanced thermal and environmental barrier coatings (TEBCs) are being developed for low-emission SiC/SiC ceramic matrix composite (CMC) combustor and vane applications to extend the CMC liner and vane temperature capability to 1650 C (3000 F) in oxidizing and water-vapor-containing combustion environments. The advanced 1650 C TEBC system is required to have a better high-temperature stability, lower thermal conductivity, and more resistance to sintering and thermal stress than current coating systems under engine high-heat-flux and severe thermal cycling conditions. In this report, the thermal conductivity and water vapor stability of selected candidate hafnia-, pyrochlore- and magnetoplumbite-based TEBC materials are evaluated. The effects of dopants on the materials properties are also discussed. The test results have been used to downselect the TEBC materials and help demonstrate the feasibility of advanced 1650 C coatings with long-term thermal cycling durability.

  7. Advances in free-energy-based simulations of protein folding and ligand binding.

    PubMed

    Perez, Alberto; Morrone, Joseph A; Simmerling, Carlos; Dill, Ken A

    2016-02-01

    Free-energy-based simulations are increasingly providing the narratives about the structures, dynamics and biological mechanisms that constitute the fabric of protein science. Here, we review two recent successes. It is becoming practical: first, to fold small proteins with free-energy methods without knowing substructures and second, to compute ligand-protein binding affinities, not just their binding poses. Over the past 40 years, the timescales that can be simulated by atomistic MD are doubling every 1.3 years--which is faster than Moore's law. Thus, these advances are not simply due to the availability of faster computers. Force fields, solvation models and simulation methodology have kept pace with computing advancements, and are now quite good. At the tip of the spear recently are GPU-based computing, improved fast-solvation methods, continued advances in force fields, and conformational sampling methods that harness external information. PMID:26773233

  8. Advances in chemical labeling of proteins in living cells

    PubMed Central

    Yan, Qi; Bruchez, Marcel P.

    2015-01-01

    Summary The pursuit of quantitative biological information with imaging requires robust labeling approaches that can be used in multiple applications and with a variety of detectable colors and properties. In addition to conventional fluorescent proteins, chemists and biologists have come together to provide a range of approaches that combine dye chemistry with the convenience of genetic targeting. This hybrid-tagging approach combines the rational design of properties available through synthetic dye chemistry with the robust biological targeting available with genetic encoding. In this review, we discuss the current range of approaches that have been exploited for dye targeting, or targeting and activation, and some of the recent applications that are uniquely enabled by these hybrid-tagging approaches. PMID:25743694

  9. Advanced biomolecular materials based on membrane-protein/polymer complexation

    SciTech Connect

    Smith, G.S.; Nowak, A.; Safinya, C.

    1998-12-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goal of this project was to apply neutron reflectometry and atomic force microscopy to the study of lipid membranes containing proteins. Standard sample preparation techniques were used to produce thin films of these materials appropriate for these techniques. However, these films were not stable, and a new sample preparation technique was required. Toward this goal, the authors have developed a new capability to produce large, freely suspended films of lipid multi-bilayers appropriate for these studies. This system includes a controlled temperature/humidity oven in which the films 5-cm x 5-cm are remotely drawn. The first neutron scattering experiments were then performed using this oven.

  10. Basics and recent advances in peptide and protein drug delivery

    PubMed Central

    Bruno, Benjamin J; Miller, Geoffrey D; Lim, Carol S

    2014-01-01

    While the peptide and protein therapeutic market has developed significantly in the past decades, delivery has limited their use. Although oral delivery is preferred, most are currently delivered intravenously or subcutaneously due to degradation and limited absorption in the gastrointestinal tract. Therefore, absorption enhancers, enzyme inhibitors, carrier systems and stability enhancers are being studied to facilitate oral peptide delivery. Additionally, transdermal peptide delivery avoids the issues of the gastrointestinal tract, but also faces absorption limitations. Due to proteases, opsonization and agglutination, free peptides are not systemically stable without modifications. This review discusses oral and transdermal peptide drug delivery, focusing on barriers and solutions to absorption and stability issues. Methods to increase systemic stability and site-specific delivery are also discussed. PMID:24228993

  11. Modeling of Total Ionizing Dose Effects in Advanced Complementary Metal-Oxide-Semiconductor Technologies

    NASA Astrophysics Data System (ADS)

    Sanchez Esqueda, Ivan

    2011-12-01

    The increased use of commercial complementary metal-oxide-semiconductor (CMOS) technologies in harsh radiation environments has resulted in a new approach to radiation effects mitigation. This approach utilizes simulation to support the design of integrated circuits (ICs) to meet targeted tolerance specifications. Modeling the deleterious impact of ionizing radiation on ICs fabricated in advanced CMOS technologies requires understanding and analyzing the basic mechanisms that result in buildup of radiation-induced defects in specific sensitive regions. Extensive experimental studies have demonstrated that the sensitive regions are shallow trench isolation (STI) oxides. Nevertheless, very little work has been done to model the physical mechanisms that result in the buildup of radiation-induced defects and the radiation response of devices fabricated in these technologies. A comprehensive study of the physical mechanisms contributing to the buildup of radiation-induced oxide trapped charges and the generation of interface traps in advanced CMOS devices is presented in this dissertation. The basic mechanisms contributing to the buildup of radiation-induced defects are explored using a physical model that utilizes kinetic equations that captures total ionizing dose (TID) and dose rate effects in silicon dioxide (SiO2). These mechanisms are formulated into analytical models that calculate oxide trapped charge density (Not) and interface trap density (Nit) in sensitive regions of deep-submicron devices. Experiments performed on field-oxide-field-effect-transistors (FOXFETs) and metal-oxide-semiconductor (MOS) capacitors permit investigating TID effects and provide a comparison for the radiation response of advanced CMOS devices. When used in conjunction with closed-form expressions for surface potential, the analytical models enable an accurate description of radiation-induced degradation of transistor electrical characteristics. In this dissertation, the incorporation

  12. Chronic ethanol consumption induces mitochondrial protein acetylation and oxidative stress in the kidney

    PubMed Central

    Harris, Peter S.; Roy, Samantha R.; Coughlan, Christina; Orlicky, David J.; Liang, Yongliang; Shearn, Colin T.; Roede, James R.; Fritz, Kristofer S.

    2015-01-01

    In this study, we present the novel findings that chronic ethanol consumption induces mitochondrial protein hyperacetylation in the kidney and correlates with significantly increased renal oxidative stress. A major proteomic footprint of alcoholic liver disease (ALD) is an increase in hepatic mitochondrial protein acetylation. Protein hyperacetylation has been shown to alter enzymatic function of numerous proteins and plays a role in regulating metabolic processes. Renal mitochondrial targets of hyperacetylation include numerous metabolic and antioxidant pathways, such as lipid metabolism, oxidative phosphorylation, and amino acid metabolism, as well as glutathione and thioredoxin pathways. Disruption of protein lysine acetylation has the potential to impair renal function through metabolic dysregulation and decreased antioxidant capacity. Due to a significant elevation in ethanol-mediated renal oxidative stress, we highlight the acetylation of superoxide dismutase, peroxiredoxins, glutathione reductase, and glutathione transferase enzymes. Since oxidative stress is a known factor in ethanol-induced nephrotoxicity, we examined biochemical markers of protein hyperacetylation and oxidative stress. Our results demonstrate increased protein acetylation concurrent with depleted glutathione, altered Cys redox potential, and the presence of 4-HNE protein modifications in our 6-week model of early-stage alcoholic nephrotoxicity. These findings support the hypothesis that ethanol metabolism causes an influx of mitochondrial metabolic substrate, resulting in mitochondrial protein hyperacetylation with the potential to impact mitochondrial metabolic and antioxidant processes. PMID:26177469

  13. Protein oxidation in processed cheese slices treated with pulsed light technology.

    PubMed

    Fernández, M; Ganan, M; Guerra, C; Hierro, E

    2014-09-15

    The effect of pulsed light technology on protein oxidation was studied in sliced processed cheese by measuring the protein-bound carbonyls with a spectrophotometric DNPH assay. Bovine serum albumin was also tested as a protein standard. Fluences of 0.7, 2.1, 4.2, 8.4 and 11.9 J/cm(2) were applied to vacuum-packaged cheese slices and to an aqueous solution of the protein. Treatments up to 4.2 J/cm(2) did not promote protein oxidation immediately after flashing either in cheese or in the standard. Samples treated with 8.4 and 11.9 J/cm(2) showed significantly higher carbonyl amounts than non-treated ones. Protein oxidation increased along cheese storage at 4°C, and differences among treatments remained. Further studies on the sensory properties will be needed to clarify the impact of pulsed light on processed cheese quality. PMID:24767071

  14. Gel-free proteomic methodologies to study reversible cysteine oxidation and irreversible protein carbonyl formation.

    PubMed

    Boronat, S; García-Santamarina, S; Hidalgo, E

    2015-05-01

    Oxidative modifications in proteins have been traditionally considered as hallmarks of damage by oxidative stress and aging. However, oxidants can generate a huge variety of reversible and irreversible modifications in amino acid side chains as well as in the protein backbones, and these post-translational modifications can contribute to the activation of signal transduction pathways, and also mediate the toxicity of oxidants. Among the reversible modifications, the most relevant ones are those arising from cysteine oxidation. Thus, formation of sulfenic acid or disulfide bonds is known to occur in many enzymes as part of their catalytic cycles, and it also participates in the activation of signaling cascades. Furthermore, these reversible modifications have been usually attributed with a protective role, since they may prevent the formation of irreversible damage by scavenging reactive oxygen species. Among irreversible modifications, protein carbonyl formation has been linked to damage and death, since it cannot be repaired and can lead to protein loss-of-function and to the formation of protein aggregates. This review is aimed at researchers interested on the biological consequences of oxidative stress, both at the level of signaling and toxicity. Here we are providing a concise overview on current mass-spectrometry-based methodologies to detect reversible cysteine oxidation and irreversible protein carbonyl formation in proteomes. We do not pretend to impose any of the different methodologies, but rather to provide an objective catwalk on published gel-free approaches to detect those two types of modifications, from a biologist's point of view. PMID:25782062

  15. Integration of advanced oxidation processes at mild conditions in wet scrubbers for odourous sulphur compounds treatment.

    PubMed

    Vega, Esther; Martin, Maria J; Gonzalez-Olmos, Rafael

    2014-08-01

    The effectiveness of different advanced oxidation processes on the treatment of a multicomponent aqueous solution containing ethyl mercaptan, dimethyl sulphide and dimethyl disulphide (0.5 mg L(-1) of each sulphur compound) was investigated with the objective to assess which one is the most suitable treatment to be coupled in wet scrubbers used in odour treatment facilities. UV/H2O2, Fenton, photo-Fenton and ozone treatments were tested at mild conditions and the oxidation efficiency obtained was compared. The oxidation tests were carried out in magnetically stirred cylindrical quartz reactors using the same molar concentration of oxidants (hydrogen peroxide or ozone). The results show that ozone and photo-Fenton are the most efficient treatments, achieving up to 95% of sulphur compounds oxidation and a mineralisation degree around 70% in 10 min. Furthermore, the total costs of the treatments taking into account the capital and operational costs were also estimated for a comparative purpose. The economic analysis revealed that the Fenton treatment is the most economical option to be integrated in a wet scrubber to remove volatile organic sulphur compounds, as long as there are no space constraints to install the required reactor volume. In the case of reactor volume limitation or retrofitting complexities, the ozone and photo-Fenton treatments should be considered as viable alternatives. PMID:24873715

  16. Enhancing hydrophilicity and water permeability of PET track-etched membranes by advanced oxidation process

    NASA Astrophysics Data System (ADS)

    Korolkov, Ilya V.; Mashentseva, Anastassiya A.; Güven, Olgun; Zdorovets, Maxim V.; Taltenov, Abzal A.

    2015-12-01

    In this study we present results on the application of advanced oxidation systems for effective and non-toxic oxidation of poly(ethylene terephthalate) track-etched membranes (PET TeMs) to improve their wettability and water transport properties. Two oxidizing systems: H2O2 under UV irradiation (H2O2/UV) and Fenton system under visible light (Fenton/H2O2/Vis) were compared. The surface of functionalized PET TeMs was characterized by using colorimetric assay, contact angle measurements and X-ray photoelectron spectroscopy (XPS). Results clearly showed that water permeability of PET TeMs treated with H2O2/UV was improved by 28 ± 5% compared with etched-only membrane, the same parameter was found to increase by 13 ± 4% in the case of Fenton/H2O2/Vis treatment. The proposed oxidation technique is very simple, environment friendly and not requiring special equipment or expensive chemicals. The surface hydrophilicity of the membranes stored for 360 days in air between paper sheets was analyzed by contact angle test, colorimetric assay to measure concentration of carboxylic groups on the surface with toluidine blue and XPS analysis. The hydrophilic properties of oxidized PET TeMs were found to be stable for a long period of time.

  17. New advanced surface modification technique: titanium oxide ceramic surface implants: long-term clinical results

    NASA Astrophysics Data System (ADS)

    Szabo, Gyorgy; Kovacs, Lajos; Barabas, Jozsef; Nemeth, Zsolt; Maironna, Carlo

    2001-11-01

    The purpose of this paper is to discuss the background to advanced surface modification technologies and to present a new technique, involving the formation of a titanium oxide ceramic coating, with relatively long-term results of its clinical utilization. Three general techniques are used to modify surfaces: the addition or removal of material and the change of material already present. Surface properties can also be changed without the addition or removal of material, through the laser or electron beam thermal treatment. The new technique outlined in this paper relates to the production of a corrosion-resistant 2000-2500 A thick, ceramic oxide layer with a coherent crystalline structure on the surface of titanium implants. The layer is grown electrochemically from the bulk of the metal and is modified by heat treatment. Such oxide ceramic-coated implants have a number of advantageous properties relative to implants covered with various other coatings: a higher external hardness, a greater force of adherence between the titanium and the oxide ceramic coating, a virtually perfect insulation between the organism and the metal (no possibility of metal allergy), etc. The coated implants were subjected to various physical, chemical, electronmicroscopic, etc. tests for a qualitative characterization. Finally, these implants (plates, screws for maxillofacial osteosynthesis and dental root implants) were applied in surgical practice for a period of 10 years. Tests and the experience acquired demonstrated the good properties of the titanium oxide ceramic-coated implants.

  18. Characterization of extracellular Mn2+-oxidizing activity and isolation of an Mn2+-oxidizing protein from Leptothrix discophora SS-1.

    PubMed

    Adams, L F; Ghiorse, W C

    1987-03-01

    Supernatant fluid from Leptothrix discophora SS-1 cultures possessed high Mn2+-ozidizing activity. Studies of temperature and pH optima, chemical inhibition, and protease sensitivity suggested that the activity may be enzymatic. Kinetic studies of unconcentrated supernatant fluid indicated an apparent Km of 7 microM Mn2+ in the 1 to 200 microM Mn2+ range. The greatest Vmax value observed was 1.4 nmol of Mn2+ oxidized min-1 micrograms of protein-1 in unconcentrated samples. When the supernatant fluid was concentrated on DEAE-cellulose and the activity was eluted with MgSO4, an Mn2+-oxidizing protein was detected in the concentrate by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The Mn2+-oxidizing protein appeared to have a molecular weight of 110,000 in 10% polyacrylamide gels and of 100,000 in 8% gels. Periodic acid-Schiff base staining of overloaded polyacrylamide gels showed that the DEAE-cellulose concentrate contained abundant high-molecular-weight polysaccharides; concurrent staining of the Mn2+-oxidizing band suggested that it too contained carbohydrate components. Isolation of the protein was achieved by subjecting the DEAE-cellulose concentrate to Sephacryl gel filtration in the presence of 1% sodium dodecyl sulfate, followed by preparative electrophoresis and reverse-polarity elution. However, these procedures resulted in loss of a large proportion of the activity, which precluded recovery of the protein in significant quality. PMID:3818545

  19. Advanced experimental analysis of controls on microbial Fe(III) oxide reduction. First year progress report

    SciTech Connect

    Roden, E.E.; Urrutia, M.M.

    1997-07-01

    'The authors have made considerable progress toward a number of project objectives during the first several months of activity on the project. An exhaustive analysis was made of the growth rate and biomass yield (both derived from measurements of cell protein production) of two representative strains of Fe(III)-reducing bacteria (Shewanellaalga strain BrY and Geobactermetallireducens) growing with different forms of Fe(III) as an electron acceptor. These two fundamentally different types of Fe(III)-reducing bacteria (FeRB) showed comparable rates of Fe(III) reduction, cell growth, and biomass yield during reduction of soluble Fe(III)-citrate and solid-phase amorphous hydrous ferric oxide (HFO). Intrinsic growth rates of the two FeRB were strongly influenced by whether a soluble or a solid-phase source of Fe(III) was provided: growth rates on soluble Fe(III) were 10--20 times higher than those on solid-phase Fe(III) oxide. Intrinsic FeRB growth rates were comparable during reduction of HF0 and a synthetic crystalline Fe(III) oxide (goethite). A distinct lag phase for protein production was observed during the first several days of incubation in solid-phase Fe(III) oxide medium, even though Fe(III) reduction proceeded without any lag. No such lag between protein production and Fe(III) reduction was observed during growth with soluble Fe(III). This result suggested that protein synthesis coupled to solid-phase Fe(III) oxide reduction in batch culture requires an initial investment of energy (generated by Fe(III) reduction), which is probably needed for synthesis of materials (e.g. extracellular polysaccharides) required for attachment of the cells to oxide surfaces. This phenomenon may have important implications for modeling the growth of FeRB in subsurface sedimentary environments, where attachment and continued adhesion to solid-phase materials will be required for maintenance of Fe(III) reduction activity. Despite considerable differences in the rate and pattern

  20. Advance chromatin extraction improves capture performance of protein A affinity chromatography.

    PubMed

    Nian, Rui; Zhang, Wei; Tan, Lihan; Lee, Jeremy; Bi, Xeuzhi; Yang, Yuansheng; Gan, Hui Theng; Gagnon, Pete

    2016-01-29

    Practical effects of advance chromatin removal on performance of protein A affinity chromatography were evaluated using a caprylic acid-allantoin-based extraction method. Lacking this treatment, the practice of increasing loading residence time to increase capacity was shown to increase host protein contamination of the eluted IgG. Advance chromatin extraction suspended that compromise. Protein A ligand leakage from columns loaded with chromatin-extracted harvest was half the level observed on protein A columns loaded with non-extracted harvest. Columns loaded with chromatin-extracted harvest were cleaned more effectively by 50-100mM NaOH than columns loaded with non-extracted harvest that were cleaned with 250-500mM NaOH. Two protein A media with IgG capacities in excess of 50g/L were loaded with chromatin-extracted harvest, washed with 2.0M NaCl before elution, and the eluted IgG fraction titrated to pH 5.5 before microfiltration. Host protein contamination in the filtrate was reduced to <1ppm, DNA to <1ppb, protein A leakage to 0.5ppm, and aggregates to 1.0%. Caprylic acid and allantoin were both reduced below 5ppm. Step recovery of IgG was 99.4%. Addition of a single polishing step reduced residual protein A beneath the level of detection and aggregates to <0.1%. Overall process recovery including chromatin extraction was 90%. PMID:26774119

  1. Protein kinase Cδ regulates endothelial nitric oxide synthase expression via Akt activation and nitric oxide generation

    PubMed Central

    Sud, Neetu; Wedgwood, Stephen; Black, Stephen M.

    2008-01-01

    In this study, we explore the roles of the delta isoform of PKC (PKCδ) in the regulation of endothelial nitric oxide synthase (eNOS) activity in pulmonary arterial endothelial cells isolated from fetal lambs (FPAECs). Pharmacological inhibition of PKCδ with either rottlerin or with the peptide, δV1-1, acutely attenuated NO production, and this was associated with a decrease in phosphorylation of eNOS at Ser1177 (S1177). The chronic effects of PKCδ inhibition using either rottlerin or the overexpression of a dominant negative PKCδ mutant included the downregulation of eNOS gene expression that was manifested by a decrease in both eNOS promoter activity and protein expression after 24 h of treatment. We also found that PKCδ inhibition blunted Akt activation as observed by a reduction in phosphorylated Akt at position Ser473. Thus, we conclude that PKCδ is actively involved in the activation of Akt. To determine the effect of Akt on eNOS signaling, we overexpressed a dominant negative mutant of Akt and determined its effect of NO generation, eNOS expression, and phosphorylation of eNOS at S1177. Our results demonstrated that Akt inhibition was associated with decreased NO production that correlated with reduced phosphorylation of eNOS at S1177, and decreased eNOS promoter activity. We next evaluated the effect of endogenously produced NO on eNOS expression by incubating FPAECs with the eNOS inhibitor 2-ethyl-2-thiopseudourea (ETU). ETU significantly inhibited NO production, eNOS promoter activity, and eNOS protein levels. Together, our data indicate involvement of PKCδ-mediated Akt activation and NO generation in maintaining eNOS expression. PMID:18192589

  2. Effects of power ultrasound on oxidation and structure of beef proteins during curing processing.

    PubMed

    Kang, Da-Cheng; Zou, Yun-He; Cheng, Yu-Ping; Xing, Lu-Juan; Zhou, Guang-Hong; Zhang, Wan-Gang

    2016-11-01

    The aim of this study was to evaluate the effects of power ultrasound intensity (PUS, 2.39, 6.23, 11.32 and 20.96Wcm(-2)) and treatment time (30, 60, 90 and 120min) on the oxidation and structure of beef proteins during the brining procedure with 6% NaCl concentration. The investigation was conducted with an ultrasonic generator with the frequency of 20kHz and fresh beef at 48h after slaughter. Analysis of TBARS (Thiobarbituric acid reactive substances) contents showed that PUS treatment significantly increased the extent of lipid oxidation compared to static brining (P<0.05). As indicators of protein oxidation, the carbonyl contents were significantly affected by PUS (P<0.05). SDS-PAGE analysis showed that PUS treatment increased protein aggregation through disulfide cross-linking, indicated by the decreasing content of total sulfhydryl groups which would contribute to protein oxidation. In addition, changes in protein structure after PUS treatment are suggested by the increases in free sulfhydryl residues and protein surface hydrophobicity. Fourier transformed infrared spectroscopy (FTIR) provided further information about the changes in protein secondary structures with increases in β-sheet and decreases in α-helix contents after PUS processing. These results indicate that PUS leads to changes in structures and oxidation of beef proteins caused by mechanical effects of cavitation and the resultant generation of free radicals. PMID:27245955

  3. A new role for Escherichia coli DsbC protein in protection against oxidative stress.

    PubMed

    Denoncin, Katleen; Vertommen, Didier; Arts, Isabelle S; Goemans, Camille V; Rahuel-Clermont, Sophie; Messens, Joris; Collet, Jean-François

    2014-05-01

    We report a new function for Escherichia coli DsbC, a protein best known for disulfide bond isomerization in the periplasm. We found that DsbC regulates the redox state of the single cysteine of the L-arabinose-binding protein AraF. This cysteine, which can be oxidized to a sulfenic acid, mediates the formation of a disulfide-linked homodimer under oxidative stress conditions, preventing L-arabinose binding. DsbC, unlike the homologous protein DsbG, reduces the intermolecular disulfide, restoring AraF binding properties. Thus, our results reveal a new link between oxidative protein folding and the defense mechanisms against oxidative stress. PMID:24634211

  4. Nitric Oxide Regulates Mitochondrial Fatty Acid Metabolism through Reversible Protein S-Nitrosylation **

    PubMed Central

    Doulias, Paschalis-Thomas; Tenopoulou, Margarita; Greene, Jennifer L.; Raju, Karthik; Ischiropoulos, Harry

    2014-01-01

    Cysteine S-nitrosylation is a posttranslational modification by which nitric oxide regulates protein function and signaling. Studies of individual proteins have elucidated specific functional roles for S-nitrosylation, but knowledge of the extent of endogenous S-nitrosylation, the sites that are nitrosylated, and the regulatory consequences of S-nitrosylation remains limited. We used mass spectrometry-based methodologies to identify 1011 S-nitrosocysteine residues in 647 proteins in various mouse tissues. We uncovered selective S-nitrosylation of enzymes participating in glycolysis, gluconeogenesis, tricarboxylic acid cycle, and oxidative phosphorylation, indicating that this posttranslational modification may regulate metabolism and mitochondrial bioenergetics. S-nitrosylation of the liver enzyme VLCAD (very long acyl-CoA dehydrogenase) at Cys238, which was absent in mice lacking endothelial nitric oxide synthase, improved its catalytic efficiency. These data implicate protein S-nitrosylation in the regulation of β-oxidation of fatty acids in mitochondria. PMID:23281369

  5. Protein Sulfenylation: A Novel Readout of Environmental Oxidant Stress

    EPA Science Inventory

    Oxidative stress is a commonly cited mechanism of toxicity of environmental agents. Ubiquitous environmental chemicals such as the diesel exhaust component 1,2-naphthoquinone (1,2-NQ)induce oxidative stress by redox cycling, which generates hydrogen peroxide (H202). Cysteinylthio...

  6. Advanced characterizations of austenitic oxide dispersion-strengthened (ODS) steels for high-temperature reactor applications

    NASA Astrophysics Data System (ADS)

    Miao, Yinbin

    Future advanced nuclear systems involve higher operation temperatures, intenser neutron flux, and more aggressive coolants, calling for structural materials with excellent performances in multiple aspects. Embedded with densely and dispersedly distributed oxide nanoparticles that are capable of not only pinning dislocations but also trapping radiation-induced defects, oxide dispersion-strengthened (ODS) steels provide excellence in mechanical strength, creep resistance, and radiation tolerance. In order to develop ODS steels with qualifications required by advanced nuclear applications, it is important to understand the fundamental mechanisms of the enhancement of ODS steels in mechanical properties. In this dissertation, a series of austenitic ODS stainless steels were investigated by coordinated state-of-the-art techniques. A series of different precipitate phases, including multiple Y-Ti-O, Y-Al-O, and Y-Ti-Hf-O complex oxides, were observed to form during mechanical alloying. Small precipitates are likely to have coherent or cubic-on-cubic orientation relationships with the matrix, allowing the dislocation to shear through. The Orowan looping mechanism is the dominant particle-dislocation interaction mode as the temperature is low, whereas the shearing mechanism and the Hirsch mechanism are also observed. Interactions between the particles and the dislocations result in the load-partitioning phenomenon. Smaller particles were found to have the stronger loading-partitioning effect. More importantly, the load-partitioning of large size particles are marginal at elevated temperatures, while the small size particles remain sustaining higher load, explaining the excellent high temperature mechanical performance of ODS steels.

  7. METHIONINE OXIDATION AND PROTEIN PHOSPHORYLATION: INTERACTIVE PARTNERS IN SIGNALING?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Protein phosphorylation can affect the activity, stability or localization of a protein and as result plays a broad role in regulation of processes ranging from metabolism to control of plant growth and development. One aspect of current interest in our lab is how protein kinases target their substr...

  8. Recent advances in metal oxide-based electrode architecture design for electrochemical energy storage.

    PubMed

    Jiang, Jian; Li, Yuanyuan; Liu, Jinping; Huang, Xintang; Yuan, Changzhou; Lou, Xiong Wen David

    2012-10-01

    Metal oxide nanostructures are promising electrode materials for lithium-ion batteries and supercapacitors because of their high specific capacity/capacitance, typically 2-3 times higher than that of the carbon/graphite-based materials. However, their cycling stability and rate performance still can not meet the requirements of practical applications. It is therefore urgent to improve their overall device performance, which depends on not only the development of advanced electrode materials but also in a large part "how to design superior electrode architectures". In the article, we will review recent advances in strategies for advanced metal oxide-based hybrid nanostructure design, with the focus on the binder-free film/array electrodes. These binder-free electrodes, with the integration of unique merits of each component, can provide larger electrochemically active surface area, faster electron transport and superior ion diffusion, thus leading to substantially improved cycling and rate performance. Several recently emerged concepts of using ordered nanostructure arrays, synergetic core-shell structures, nanostructured current collectors, and flexible paper/textile electrodes will be highlighted, pointing out advantages and challenges where appropriate. Some future electrode design trends and directions are also discussed. PMID:22912066

  9. Japanese Encephalitis Virus Nonstructural Protein NS5 Interacts with Mitochondrial Trifunctional Protein and Impairs Fatty Acid β-Oxidation

    PubMed Central

    Kao, Yu-Ting; Chang, Bi-Lan; Liang, Jian-Jong; Tsai, Hang-Jen; Lee, Yi-Ling; Lin, Ren-Jye; Lin, Yi-Ling

    2015-01-01

    Infection with Japanese encephalitis virus (JEV) can induce the expression of pro-inflammatory cytokines and cause acute encephalitis in humans. β-oxidation breaks down fatty acids for ATP production in mitochondria, and impaired β-oxidation can induce pro-inflammatory cytokine expression. To address the role of fatty-acid β-oxidation in JEV infection, we measured the oxygen consumption rate of mock- and JEV-infected cells cultured with or without long chain fatty acid (LCFA) palmitate. Cells with JEV infection showed impaired LCFA β-oxidation and increased interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) expression. JEV nonstructural protein 5 (NS5) interacted with hydroxyacyl-CoA dehydrogenase α and β subunits, two components of the mitochondrial trifunctional protein (MTP) involved in LCFA β-oxidation, and NS5 proteins were detected in mitochondria and co-localized with MTP. LCFA β-oxidation was impaired and higher cytokines were induced in cells overexpressing NS5 protein as compared with control cells. Deletion and mutation studies showed that the N-terminus of NS5 was involved in the MTP association, and a single point mutation of NS5 residue 19 from methionine to alanine (NS5-M19A) reduced its binding ability with MTP. The recombinant JEV with NS5-M19A mutation (JEV-NS5-M19A) was less able to block LCFA β-oxidation and induced lower levels of IL-6 and TNF-α than wild-type JEV. Moreover, mice challenged with JEV-NS5-M19A showed less neurovirulence and neuroinvasiveness. We identified a novel function of JEV NS5 in viral pathogenesis by impairing LCFA β-oxidation and inducing cytokine expression by association with MTP. PMID:25816318

  10. Branched-Chain Amino Acid Supplementation Reduces Oxidative Stress and Prolongs Survival in Rats with Advanced Liver Cirrhosis

    PubMed Central

    Mifuji-Moroka, Rumi; Hara, Nagisa; Miyachi, Hirohide; Sugimoto, Ryosuke; Tanaka, Hideaki; Fujita, Naoki; Gabazza, Esteban C.; Takei, Yoshiyuki

    2013-01-01

    Long-term supplementation with branched-chain amino acids (BCAA) is associated with prolonged survival and decreased frequency of development of hepatocellular carcinoma (HCC) in patients with liver cirrhosis. However, the pharmaceutical mechanism underlying this association is still unclear. We investigated whether continuous BCAA supplementation increases survival rate of rats exposed to a fibrogenic agent and influences the iron accumulation, oxidative stress, fibrosis, and gluconeogenesis in the liver. Further, the effects of BCAA on gluconeogenesis in cultured cells were also investigated. A significant improvement in cumulative survival was observed in BCAA-supplemented rats with advanced cirrhosis compared to untreated rats with cirrhosis (P<0.05). The prolonged survival due to BCAA supplementation was associated with reduction of iron contents, reactive oxygen species production and attenuated fibrosis in the liver. In addition, BCAA ameliorated glucose metabolism by forkhead box protein O1 pathway in the liver. BCAA prolongs survival in cirrhotic rats and this was likely the consequences of reduced iron accumulation, oxidative stress and fibrosis and improved glucose metabolism in the liver. PMID:23936183

  11. Advances in membrane protein crystallography: in situ and in meso data collection

    SciTech Connect

    Weyand, Simone; Tate, Christopher G.

    2015-05-23

    Membrane protein structural biology has made tremendous advances over the last decade but there are still many challenges associated with crystallization, data collection and structure determination. Two independent groups, Axford et al. [(2015), Acta Cryst. D71, 1228–1237] and Huang et al. [(2015), Acta Cryst. D71, 1238–1256], have published methods that make a major contribution to addressing these challenges.

  12. Advanced treatment of effluents from an industrial park wastewater treatment plant by ferrous ion activated persulfate oxidation process.

    PubMed

    Zhu, Songmei; Zhou, Zhen; Jiang, Haitao; Ye, Jianfeng; Ren, Jiamin; Gu, Lingyun; Wang, Luochun

    2016-01-01

    The advanced oxidation technology, ferrous ion (Fe(II)) activated persulfate (PS) producing sulfate radicals, was used for the advanced treatment of effluent from an integrated wastewater treatment plant in a papermaking industrial park. Separate and interactive effects of PS dosage, Fe(II)/PS ratio and initial pH on chemical oxygen demand (COD) removal were analyzed by the response surface methodology (RSM). The results showed that Fe(II)-PS system was effective in COD removal from the secondary effluent. PS dosage was the most dominant factor with positive influence on COD removal, followed by initial pH value. The optimum conditions with COD removal of 54.4% were obtained at PS/COD of 2.2, initial pH of 6.47 and Fe(II)/PS of 1.89. UV-visible spectrum analysis showed that after RSM optimization, Fe(II)-PS system effectively degraded large organic molecules into small ones, and decreased humification degree of the effluent. Three-dimensional fluorescence analysis demonstrated that aromatic protein and fulvic substances were fully decomposed by the Fe(II)-PS treatment. PMID:27438260

  13. Nucleation of Iron Oxide Nanoparticles Mediated by Mms6 Protein in Situ

    SciTech Connect

    Kashyap, Sanjay; Woehl, Taylor J; Liu, Xunpei; Mallapragada, Surya K; Prozorov, Tanya

    2014-09-23

    Biomineralization proteins are widely used as templating agents in biomimetic synthesis of a variety of organic–inorganic nanostructures. However, the role of the protein in controlling the nucleation and growth of biomimetic particles is not well understood, because the mechanism of the bioinspired reaction is often deduced from ex situ analysis of the resultant nanoscale mineral phase. Here we report the direct visualization of biomimetic iron oxide nanoparticle nucleation mediated by an acidic bacterial recombinant protein, Mms6, during an in situ reaction induced by the controlled addition of sodium hydroxide to solution-phase Mms6 protein micelles incubated with ferric chloride. Using in situ liquid cell scanning transmission electron microscopy we observe the liquid iron prenucleation phase and nascent amorphous nanoparticles forming preferentially on the surface of protein micelles. Our results provide insight into the early steps of protein-mediated biomimetic nucleation of iron oxide and point to the importance of an extended protein surface during nanoparticle formation.

  14. Balancing oxidative protein folding: the influences of reducing pathways on disulfide bond formation.

    PubMed

    Kojer, Kerstin; Riemer, Jan

    2014-08-01

    Oxidative protein folding is confined to few compartments, including the endoplasmic reticulum, the mitochondrial intermembrane space and the bacterial periplasm. Conversely, in compartments in which proteins are translated such as the cytosol, the mitochondrial matrix and the chloroplast stroma proteins are kept reduced by the thioredoxin and glutaredoxin systems that functionally overlap. The highly reducing NADPH pool thereby serves as electron donor that enables glutathione reductase and thioredoxin reductase to keep glutathione pools and thioredoxins in their reduced redox state, respectively. Notably, also compartments containing oxidizing machineries are linked to these reducing pathways. Reducing pathways aid in proofreading of disulfide bond formation by isomerization or they provide reducing equivalents for the reduction of disulfides prior to degradation. In addition, they contribute to the thiol-dependent regulation of protein activities, and they help to counteract oxidative stress. The existence of oxidizing and reducing pathways in the same compartment poses a potential problem as the cell has to avoid futile cycles of oxidation and subsequent reduction reactions. Thus, compartments that contain oxidizing machineries have developed sophisticated ways to spatiotemporally balance and regulate oxidation and reduction. In this review, we discuss oxidizing and reducing pathways in the endoplasmic reticulum, the periplasm and the mitochondrial intermembrane space and highlight the role of glutathione especially in the endoplasmic reticulum and the intermembrane space. This article is part of a Special Issue entitled: Thiol-Based Redox Processes. PMID:24534645

  15. Desialylation of plasma proteins in severe dengue infection: possible role of oxidative stress.

    PubMed

    Rajendiran, Soundravally; Lakshamanappa, Hoti Sugeerappa; Zachariah, Bobby; Nambiar, Selvaraj

    2008-09-01

    Oxidative stress in dengue infection has been suggested. This study was carried out to explore the plasma protein oxidation and its sialic acid content in dengue infection. Thirty-two dengue hemorrhagic fever (DHF), 25 dengue shock syndrome (DSS), 29 dengue fever (DF), and 63 healthy controls were included in this study. The extent of carbonylation, sulphydryl content, and desialylation of plasma protein was estimated in acute phase sample. Significantly higher levels of protein carbonyls and lower levels of sialic acid and sulphydryl groups were found in DHF and DSS compared with DF using one-way analysis of variance. Regression analysis showed that desialylation is dependent on protein carbonyls in DHF/DSS. This study indicates that, in dengue infection, plasma proteins undergo increased levels of desialylation, which can be attributed to the oxidative stress. Future studies on sialylation status of endothelium and platelets can show light into the pathogenesis of the dengue infection. PMID:18784228

  16. Increased methyl esterification of altered aspartyl residues in erythrocyte membrane proteins in response to oxidative stress.

    PubMed

    Ingrosso, D; D'angelo, S; di Carlo, E; Perna, A F; Zappia, V; Galletti, P

    2000-07-01

    Protein-L-isoaspartate (D-aspartate) O-methyltransferase (PCMT; EC 2. 1.1.77) catalyses the methyl esterification of the free alpha-carboxyl group of abnormal L-isoaspartyl residues, which occur spontaneously in protein and peptide substrates as a consequence of molecular ageing. The biological function of this transmethylation reaction is related to the repair or degradation of age-damaged proteins. Methyl ester formation in erythrocyte membrane proteins has also been used as a marker reaction to tag these abnormal residues and to monitor their increase associated with erythrocyte ageing diseases, such as hereditary spherocytosis, or cell stress (thermal or osmotic) conditions. The study shows that levels of L-isoaspartyl residues rise in membrane proteins of human erythrocytes exposed to oxidative stress, induced by t-butyl hydroperoxide or H2O2. The increase in malondialdehyde content confirmed that the cell membrane is a primary target of oxidative alterations. A parallel rise in the methaemoglobin content indicates that proteins are heavily affected by the molecular alterations induced by oxidative treatments in erythrocytes. Antioxidants largely prevented the increase in membrane protein methylation, underscoring the specificity of the effect. Conversely, we found that PCMT activity, consistent with its repair function, remained remarkably stable under oxidative conditions, while damaged membrane protein substrates increased significantly. The latter include ankyrin, band 4.1 and 4.2, and the integral membrane protein band 3 (the anion exchanger). The main target was found to be particularly protein 4.1, a crucial element in the maintenance of membrane-cytoskeleton network stability. We conclude that the increased formation/exposure of L-isoaspartyl residues is one of the major structural alterations occurring in erythrocyte membrane proteins as a result of an oxidative stress event. In the light of these and previous findings, the occurrence of isoaspartyl

  17. Oxidative degradation of endotoxin by advanced oxidation process (O3/H2O2 & UV/H2O2).

    PubMed

    Oh, Byung-Taek; Seo, Young-Suk; Sudhakar, Dega; Choe, Ji-Hyun; Lee, Sang-Myeong; Park, Youn-Jong; Cho, Min

    2014-08-30

    The presence of endotoxin in water environments may pose a serious public health hazard. We investigated the effectiveness of advanced oxidative processes (AOP: O3/H2O2 and UV/H2O2) in the oxidative degradation of endotoxin. In addition, we measured the release of endotoxin from Escherichia coli following typical disinfection methods, such as chlorine, ozone alone and UV, and compared it with the use of AOPs. Finally, we tested the AOP-treated samples in their ability to induce tumor necrosis factor alpha (TNF-α) in mouse peritoneal macrophages. The production of hydroxyl radical in AOPs showed superior ability to degrade endotoxin in buffered solution, as well as water samples from Korean water treatment facilities, with the ozone/H2O2 being more efficient compared to UV/H2O2. In addition, the AOPs proved effective not only in eliminating E. coli in the samples, but also in endotoxin degradation, while the standard disinfection methods lead to the release of endotoxin following the bacteria destruction. Furthermore, in the experiments with macrophages, the AOPs-deactivated endotoxin lead to the smallest induction of TNF-α, which shows the loss of inflammation activity, compared to ozone treatment alone. In conclusion, these results suggest that AOPs offer an effective and mild method for endotoxin degradation in the water systems. PMID:25038578

  18. Biodegradability of iopromide products after UV/H₂O₂ advanced oxidation.

    PubMed

    Keen, Olya S; Love, Nancy G; Aga, Diana S; Linden, Karl G

    2016-02-01

    Iopromide is an X-ray and MRI contrast agent that is virtually non-biodegradable and persistent through typical wastewater treatment processes. This study determined whether molecular transformation of iopromide in a UV/H2O2 advanced oxidation process (AOP) can result in biodegradable products. The experiments used iopromide labeled with carbon-14 on the aromatic ring to trace degradation of iopromide through UV/H2O2 advanced oxidation and subsequent biodegradation. The biotransformation assay tracked the formation of radiolabeled (14)CO2 which indicated full mineralization of the molecule. The results indicated that AOP formed biodegradable iopromide products. There was no (14)C released from the pre-AOP samples, but up to 20% of all radiolabeled carbon transformed into (14)CO2 over the course of 42 days of biodegradation after iopromide was exposed to advanced oxidation (compared to 10% transformation in inactivated post-AOP controls). In addition, the quantum yield of photolysis of iopromide was determined using low pressure (LP) and medium pressure (MP) mercury lamps as 0.069 ± 0.005 and 0.080 ± 0.007 respectively. The difference in the quantum yields for the two UV sources was not statistically significant at the 95% confidence interval (p = 0.08), which indicates the equivalency of using LP or MP UV sources for iopromide treatment. The reaction rate between iopromide and hydroxyl radicals was measured to be (2.5 ± 0.2) × 10(9) M(-1) s(-1). These results indicate that direct photolysis is a dominant degradation pathway in UV/H2O2 AOP treatment of iopromide. Other iodinated contrast media may also become biodegradable after exposure to UV or UV/H2O2. PMID:26433937

  19. UV irradiation and UV-H₂O₂ advanced oxidation of the roxarsone and nitarsone organoarsenicals.

    PubMed

    Adak, Asok; Mangalgiri, Kiranmayi P; Lee, Jessica; Blaney, Lee

    2015-03-01

    Roxarsone (ROX) and nitarsone (NIT) are used as additives in animal feeding operations and have been detected in animal manure, agricultural retention ponds, and adjacent surface waters. This work investigates treatment of organoarsenicals using UV-based treatment processes, namely UV irradiation at 253.7 nm and the UV-H2O2 advanced oxidation process. The apparent molar absorptivity was mapped for ROX and NIT across pH and wavelength. For UV irradiation at 253.7 nm, the fluence-based pseudo-first order rate constant (kp(')) and effective quantum yield (Φ) for ROX were 8.10-29.7 × 10(-5) cm(2)/mJ and 2.34-8.37 × 10(-3) mol/E, respectively; the corresponding constants were slightly lower for NIT. The observed rate constants are higher during advanced oxidation (e.g., kp,ROX(')=3.92(±0.19)-217(±48) × 10(-4) cm(2)/mJ). Second order rate constants for organoarsenical transformation by hydroxyl radicals were determined to be 3.40(±0.45) × 10(9) and 8.28(±0.49) × 10(8) M(-1)s(-1) for ROX and NIT, respectively. Solution pH and nitrate concentration did not significantly impact ROX transformation during advanced oxidation; however, bicarbonate and dissolved organic matter from chicken litter reduced ROX transformation through hydroxyl radical scavenging. Inorganic arsenic was the predominant transformation product of ROX during UV-H2O2 treatment. PMID:25514660

  20. Methionine sulfoxide profiling of milk proteins to assess the influence of lipids on protein oxidation in milk.

    PubMed

    Wüst, Johannes; Pischetsrieder, Monika

    2016-06-15

    Thermal treatment of milk and milk products leads to protein oxidation, mainly the formation of methionine sulfoxide. Reactive oxygen species, responsible for the oxidation, can be generated by Maillard reaction, autoxidation of sugars, or lipid peroxidation. The present study investigated the influence of milk fat on methionine oxidation in milk. For this purpose, quantitative methionine sulfoxide profiling of all ten methionine residues of β-lactoglobulin, α-lactalbumin, and αs1-casein was carried out by ultrahigh-performance liquid chromatography-electrospray ionization tandem mass spectrometry with scheduled multiple reaction monitoring (UHPLC-ESI-MS/MS-sMRM). Analysis of defatted and regular raw milk samples after heating for up to 8 min at 120 °C and analysis of ultrahigh-temperature milk samples with 0.1%, 1.5%, and 3.5% fat revealed that methionine oxidation of the five residues of the whey proteins and of residues M 123, M 135, and M 196 of αs1-casein was not affected or even suppressed in the presence of milk fat. Only the oxidation of residues M 54 and M 60 of αs1-casein was promoted by lipids. In evaporated milk samples, formation of methionine sulfoxide was hardly influenced by the fat content of the samples. Thus, it can be concluded that lipid oxidation products are not the major cause of methionine oxidation in milk. PMID:26927981

  1. Reduction of antibiotic resistance genes in municipal wastewater effluent by advanced oxidation processes.

    PubMed

    Zhang, Yingying; Zhuang, Yao; Geng, Jinju; Ren, Hongqiang; Xu, Ke; Ding, Lili

    2016-04-15

    This study investigated the reduction of antibiotic resistance genes (ARGs), intI1 and 16S rRNA genes, by advanced oxidation processes (AOPs), namely Fenton oxidation (Fe(2+)/H2O2) and UV/H2O2 process. The ARGs include sul1, tetX, and tetG from municipal wastewater effluent. The results indicated that the Fenton oxidation and UV/H2O2 process could reduce selected ARGs effectively. Oxidation by the Fenton process was slightly better than that of the UV/H2O2 method. Particularly, for the Fenton oxidation, under the optimal condition wherein Fe(2+)/H2O2 had a molar ratio of 0.1 and a H2O2 concentration of 0.01molL(-1) with a pH of 3.0 and reaction time of 2h, 2.58-3.79 logs of target genes were removed. Under the initial effluent pH condition (pH=7.0), the removal was 2.26-3.35 logs. For the UV/H2O2 process, when the pH was 3.5 with a H2O2 concentration of 0.01molL(-1) accompanied by 30min of UV irradiation, all ARGs could achieve a reduction of 2.8-3.5 logs, and 1.55-2.32 logs at a pH of 7.0. The Fenton oxidation and UV/H2O2 process followed the first-order reaction kinetic model. The removal of target genes was affected by many parameters, including initial Fe(2+)/H2O2 molar ratios, H2O2 concentration, solution pH, and reaction time. Among these factors, reagent concentrations and pH values are the most important factors during AOPs. PMID:26815295

  2. Post-treatment of reclaimed waste water based on an electrochemical advanced oxidation process

    NASA Technical Reports Server (NTRS)

    Verostko, Charles E.; Murphy, Oliver J.; Hitchens, G. D.; Salinas, Carlos E.; Rogers, Tom D.

    1992-01-01

    The purification of reclaimed water is essential to water reclamation technology life-support systems in lunar/Mars habitats. An electrochemical UV reactor is being developed which generates oxidants, operates at low temperatures, and requires no chemical expendables. The reactor is the basis for an advanced oxidation process in which electrochemically generated ozone and hydrogen peroxide are used in combination with ultraviolet light irradiation to produce hydroxyl radicals. Results from this process are presented which demonstrate concept feasibility for removal of organic impurities and disinfection of water for potable and hygiene reuse. Power, size requirements, Faradaic efficiency, and process reaction kinetics are discussed. At the completion of this development effort the reactor system will be installed in JSC's regenerative water recovery test facility for evaluation to compare this technique with other candidate processes.

  3. Removal of residual pharmaceuticals from aqueous systems by advanced oxidation processes.

    PubMed

    Klavarioti, Maria; Mantzavinos, Dionissios; Kassinos, Despo

    2009-02-01

    Over the past few years, pharmaceuticals are considered as an emerging environmental problem due to their continuous input and persistence to the aquatic ecosystem even at low concentrations. Advanced oxidation processes (AOPs) are technologies based on the intermediacy of hydroxyl and other radicals to oxidize recalcitrant, toxic and non-biodegradable compounds to various by-products and eventually to inert end-products. The environmental applications of AOPs are numerous, including water and wastewater treatment (i.e. removal of organic and inorganic pollutants and pathogens), air pollution abatement and soil remediation. AOPs are applied for the abatement of pollution caused by the presence of residual pharmaceuticals in waters for the last decade. In this light, this paper reviews and assesses the effectiveness of various AOPs for pharmaceutical removal from aqueous systems. PMID:18760478

  4. Advanced Oxide Material Systems For 1650 C Thermal/Environmental Barrier Coating Applications

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Fox, Dennis S.; Bansal, Narottam P.; Miller, Robert A.

    2004-01-01

    Advanced thermal/environmental barrier coatings (T/EBCs) are being developed for low emission SiC/SiC ceramic matrix composite (CMC) combustor and vane applications to extend the CMC liner and vane temperature capability to 1650 C (3000 F) in oxidizing and water-vapor containing combustion environments. The 1650 C T/EBC system is required to have better thermal stability, lower thermal conductivity, and improved sintering and thermal stress resistance than current coating systems. In this paper, the thermal conductivity, water vapor stability and cyclic durability of selected candidate zirconia-/hafnia-, pyrochlore- and magnetoplumbite-based T/EBC materials are evaluated. The test results have been used to downselect the T/EBC coating materials, and help demonstrate advanced 1650OC coatings feasibility with long-term cyclic durability.

  5. Oxide semiconductor thin-film transistors: a review of recent advances.

    PubMed

    Fortunato, E; Barquinha, P; Martins, R

    2012-06-12

    Transparent electronics is today one of the most advanced topics for a wide range of device applications. The key components are wide bandgap semiconductors, where oxides of different origins play an important role, not only as passive component but also as active component, similar to what is observed in conventional semiconductors like silicon. Transparent electronics has gained special attention during the last few years and is today established as one of the most promising technologies for leading the next generation of flat panel display due to its excellent electronic performance. In this paper the recent progress in n- and p-type oxide based thin-film transistors (TFT) is reviewed, with special emphasis on solution-processed and p-type, and the major milestones already achieved with this emerging and very promising technology are summarizeed. After a short introduction where the main advantages of these semiconductors are presented, as well as the industry expectations, the beautiful history of TFTs is revisited, including the main landmarks in the last 80 years, finishing by referring to some papers that have played an important role in shaping transparent electronics. Then, an overview is presented of state of the art n-type TFTs processed by physical vapour deposition methods, and finally one of the most exciting, promising, and low cost but powerful technologies is discussed: solution-processed oxide TFTs. Moreover, a more detailed focus analysis will be given concerning p-type oxide TFTs, mainly centred on two of the most promising semiconductor candidates: copper oxide and tin oxide. The most recent data related to the production of complementary metal oxide semiconductor (CMOS) devices based on n- and p-type oxide TFT is also be presented. The last topic of this review is devoted to some emerging applications, finalizing with the main conclusions. Related work that originated at CENIMAT|I3N during the last six years is included in more detail, which

  6. Degradation of the commercial surfactant nonylphenol ethoxylate by advanced oxidation processes.

    PubMed

    da Silva, Salatiel Wohlmuth; Klauck, Cláudia Regina; Siqueira, Marco Antônio; Bernardes, Andréa Moura

    2015-01-23

    Four different oxidation process, namely direct photolysis (DP) and three advanced oxidation processes (heterogeneous photocatalysis - HP, eletrochemical oxidation - EO and photo-assisted electrochemical oxidation - PEO) were applied in the treatment of wastewater containing nonylphenol ethoxylate (NPnEO). The objective of this work was to determine which treatment would be the best option in terms of degradation of NPnEO without the subsequent generation of toxic compounds. In order to investigate the degradation of the surfactant, the processes were compared in terms of UV/Vis spectrum, mineralization (total organic carbon), reaction kinetics, energy efficiency and phytotoxicity. A solution containing NPnEO was prepared as a surrogate of the degreasing wastewater, was used in the processes. The results showed that the photo-assisted processes degrade the surfactant, producing biodegradable intermediates in the reaction. On the other hand, the electrochemical process influences the mineralization of the surfactant. The process of PEO carried out with a 250W lamp and a current density of 10mA/cm(2) showed the best results in terms of degradation, mineralization, reaction kinetics and energy consumption, in addition to not presenting phytotoxicity. Based on this information, this process can be a viable alternative for treating wastewater containing NPnEO, avoiding the contamination of water resources. PMID:25262384

  7. Engineered crumpled graphene oxide nanocomposite membrane assemblies for advanced water treatment processes.

    PubMed

    Jiang, Yi; Wang, Wei-Ning; Liu, Di; Nie, Yao; Li, Wenlu; Wu, Jiewei; Zhang, Fuzhong; Biswas, Pratim; Fortner, John D

    2015-06-01

    In this work, we describe multifunctional, crumpled graphene oxide (CGO) porous nanocomposites that are assembled as advanced, reactive water treatment membranes. Crumpled 3D graphene oxide based materials fundamentally differ from 2D flat graphene oxide analogues in that they are highly aggregation and compression-resistant (i.e., π-π stacking resistant) and allow for the incorporation (wrapping) of other, multifunctional particles inside the 3D, composite structure. Here, assemblies of nanoscale, monomeric CGO with encapsulated (as a quasi core-shell structure) TiO2 (GOTI) and Ag (GOAg) nanoparticles, not only allow high water flux via vertically tortuous nanochannels (achieving water flux of 246 ± 11 L/(m(2)·h·bar) with 5.4 μm thick assembly, 7.4 g/m(2)), outperforming comparable commercial ultrafiltration membranes, but also demonstrate excellent separation efficiencies for model organic and biological foulants. Further, multifunctionality is demonstrated through the in situ photocatalytic degradation of methyl orange (MO), as a model organic, under fast flow conditions (tres < 0.1 s); while superior antimicrobial properties, evaluated with GOAg, are observed for both biofilm (contact) and suspended growth scenarios (>3 log effective removal, Escherichia coli). This is the first demonstration of 3D, crumpled graphene oxide based nanocomposite structures applied specifically as (re)active membrane assemblies and highlights the material's platform potential for a truly tailored approach for next generation water treatment and separation technologies. PMID:25942505

  8. Occurrence and Removal of Organic Micropollutants in Landfill Leachates Treated by Electrochemical Advanced Oxidation Processes.

    PubMed

    Oturan, Nihal; van Hullebusch, Eric D; Zhang, Hui; Mazeas, Laurent; Budzinski, Hélène; Le Menach, Karyn; Oturan, Mehmet A

    2015-10-20

    In recent years, electrochemical advanced oxidation processes have been shown to be an effective alternative for the removal of refractory organic compounds from water. This study is focused on the effective removal of recalcitrant organic matter (micropollutants, humic substances, etc.) present in municipal solid waste landfill leachates. A mixture of eight landfill leachates has been studied by the electro-Fenton process using a Pt or boron-doped diamond (BDD) anode and a carbon felt cathode or by the anodic oxidation process with a BDD anode. These processes exhibit great oxidation ability due to the in situ production of hydroxyl radicals ((•)OH), a highly powerful oxidizing species. Both electrochemical processes were shown to be efficient in the removal of dissolved total organic carbon (TOC) from landfill leachates. Regarding the electro-Fenton process, the replacement of the classical anode Pt by the anode BDD allows better performance in terms of dissolved TOC removal. The occurrence and removal yield of 19 polycyclic aromatic hydrocarbons, 15 volatile organic compounds, 7 alkylphenols, 7 polychlorobiphenyls, 5 organochlorine pesticides, and 2 polybrominated diphenyl ethers in landfill leachate were also investigated. Both electrochemical processes allow one to reach a quasicomplete removal (about 98%) of these organic micropollutants. PMID:26378656

  9. Contribution of free radicals to chlorophenols decomposition by several advanced oxidation processes.

    PubMed

    Benitez, F J; Beltran-Heredia, J; Acero, J L; Rubio, F J

    2000-10-01

    The chemical decomposition of aqueous solutions of various chlorophenols (4-chlorophenol (4-CP), 2,4-dichlorophenol (2-DCP), 2,4,6-trichlorophenol (2,4,6-TCP) and 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP)), which are environmental priority pollutants, is studied by means of single oxidants (hydrogen peroxide, UV radiation, Fenton's reagent and ozone at pH 2 and 9), and by the Advanced Oxidation Processes (AOPs) constituted by combinations of these oxidants (UV/H2O2 UV/Fenton's reagent and O3/UV). For all these reactions the degradation rates are evaluated by determining their first-order rate constants and the half-life times. Ozone is more reactive with higher substituted CPs while OH* radicals react faster with those chlorophenols having lower number of chlorine atoms. The improvement in the decomposition levels reached by the combined processes, due to the generation of the very reactive hydroxyl radicals. in relation to the single oxidants is clearly demonstrated and evaluated by kinetic modeling. PMID:10901258

  10. Sono-bromination of aromatic compounds based on the ultrasonic advanced oxidation processes.

    PubMed

    Fujita, Mitsue; Lévêque, Jean-Marc; Komatsu, Naoki; Kimura, Takahide

    2015-11-01

    A novel, mild "sono-halogenation" of various aromatic compounds with potassium halide was investigated under ultrasound in a biphasic carbon tetrachloride/water medium. The feasibility study was first undertaken with the potassium bromide and then extended to chloride and iodide analogues. This methodology could be considered as a new expansion of the ultrasonic advanced oxidation processes (UAOPs) into a synthetic aspect as the developed methodology is linked to the sonolytic disappearance of carbon tetrachloride. Advantages of the present method are not only that the manipulation of the bromination is simple and green, but also that the halogenating agents used are readily available, inexpensive, and easy-handling. PMID:26186842

  11. Combining Advanced Oxidation Processes: Assessment Of Process Additivity, Synergism, And Antagonism

    SciTech Connect

    Peters, Robert W.; Sharma, M.P.; Gbadebo Adewuyi, Yusuf

    2007-07-01

    This paper addresses the process interactions from combining integrated processes (such as advanced oxidation processes (AOPs), biological operations, air stripping, etc.). AOPs considered include: Fenton's reagent, ultraviolet light, titanium dioxide, ozone (O{sub 3}), hydrogen peroxide (H{sub 2}O{sub 2}), sonication/acoustic cavitation, among others. A critical review of the technical literature has been performed, and the data has been analyzed in terms of the processes being additive, synergistic, or antagonistic. Predictions based on the individual unit operations are made and compared against the behavior of the combined unit operations. The data reported in this paper focus primarily on treatment of petroleum hydrocarbons and chlorinated solvents. (authors)

  12. Monolithic solid oxide fuel cell technology advancement for coal- based power generation. Quarterly report, December 1991

    SciTech Connect

    Not Available

    1992-01-15

    The program is conducted by a team consisting of AiResearch Los Angeles Division of Allied-Signal Aerospace Company and Argonne National Laboratory (ANL). The objective of the program is to advance materials and fabrication methodologies to develop a monolithic solid oxide fuel cell (MSOFC) system capable of meeting performance, life, and cost goals for coal-based power generation. The program focuses on materials research and development, fabrication process development, cell/stack performance testing and characterization, cost and system analysis, and quality development.

  13. Monolithic solid oxide fuel cell technology advancement for coal- based power generation

    SciTech Connect

    Not Available

    1992-01-15

    The program is conducted by a team consisting of AiResearch Los Angeles Division of Allied-Signal Aerospace Company and Argonne National Laboratory (ANL). The objective of the program is to advance materials and fabrication methodologies to develop a monolithic solid oxide fuel cell (MSOFC) system capable of meeting performance, life, and cost goals for coal-based power generation. The program focuses on materials research and development, fabrication process development, cell/stack performance testing and characterization, cost and system analysis, and quality development.

  14. Advanced glycosylation endproducts block the antiproliferative effect of nitric oxide. Role in the vascular and renal complications of diabetes mellitus.

    PubMed

    Hogan, M; Cerami, A; Bucala, R

    1992-09-01

    Advanced glycosylation endproducts (AGEs) accumulate on long-lived tissue proteins such as basement membrane collagen and have been implicated in many of the long-term complications of diabetes mellitus. These products originate from glucose-derived Schiff base and Amadori products but undergo a series of complex rearrangement reactions to form ultimately protein-bound, fluorescent heterocycles. AGEs can react with and chemically inactivate nitric oxide (NO), a potent endothelial cell-derived vasodilator and antiproliferative factor. Since mesenchymal cell proliferation is an early and characteristic lesion of diabetic vasculopathy and glomerulopathy, we investigated the possibility that collagen-bound AGEs functionally inactivate the antiproliferative effect of NO. In model cell culture systems, AGEs were found to block the cytostatic effect of NO on aortic smooth muscle and renal mesangial cells. The inactivation of endothelial cell-derived NO by basement membrane AGEs may represent a common pathway in the development of the accelerated vascular and renal disease that accompany long-term diabetes mellitus. PMID:1522220

  15. Treatment of statin compounds by advanced oxidation processes: Kinetic considerations and destruction mechanisms

    NASA Astrophysics Data System (ADS)

    Razavi, Behnaz; Song, Weihua; Santoke, Hanoz; Cooper, William J.

    2011-03-01

    This study examined the use of advanced oxidation/reduction processes (AO/RPs) for the destruction of cholesterol lowering statin pharmaceuticals. AO/RPs which utilize the oxidizing hydroxyl radical ( rad OH) and reducing aqueous electron (e -aq), to degrade chemical contaminants are alternatives to traditional water treatment methods, and are alternatives as water reuse becomes more generally implemented. Four major statin pharmaceuticals, fluvastatin, lovastatin, pravastatin and simvastatin, were studied, and the absolute bimolecular reaction rate constants with rad OH determined, (6.96±0.16)×10 9, (2.92±0.06)×10 9, (4.16±0.13)×10 9, and (3.13±0.15)×10 9 M -1 s -1, and for e -aq (2.31±0.06)×10 9, (0.45±0.01)×10 9, (1.26±0.01)×10 9, and (0.69±0.02)×10 9 M -1 s -1, respectively. To provide additional information on the radicals formed upon oxidation, transient spectra were measured and the overall reaction efficiency determined. Radical-based destruction mechanisms for destruction of the statins are proposed based on the LC-MS determination of the stable reaction by-products formed using 137Cs γ-irradiation of statin solutions. Knowing the reaction rates, reaction efficiencies and destruction mechanisms of these compounds is essential for the consideration of the use of advanced oxidation/reduction processes for the destruction of statins in aqueous systems.

  16. Characterization of methionine oxidation and methionine sulfoxide reduction using methionine-rich cysteine-free proteins

    PubMed Central

    2012-01-01

    Background Methionine (Met) residues in proteins can be readily oxidized by reactive oxygen species to Met sulfoxide (MetO). MetO is a promising physiological marker of oxidative stress and its inefficient repair by MetO reductases (Msrs) has been linked to neurodegeneration and aging. Conventional methods of assaying MetO formation and reduction rely on chromatographic or mass spectrometry procedures, but the use of Met-rich proteins (MRPs) may offer a more streamlined alternative. Results We carried out a computational search of completely sequenced genomes for MRPs deficient in cysteine (Cys) residues and identified several proteins containing 20% or more Met residues. We used these MRPs to examine Met oxidation and MetO reduction by in-gel shift assays and immunoblot assays with antibodies generated against various oxidized MRPs. The oxidation of Cys-free MRPs by hydrogen peroxide could be conveniently monitored by SDS-PAGE and was specific for Met, as evidenced by quantitative reduction of these proteins with Msrs in DTT- and thioredoxin-dependent assays. We found that hypochlorite was especially efficient in oxidizing MRPs. Finally, we further developed a procedure wherein antibodies made against oxidized MRPs were isolated on affinity resins containing same or other oxidized or reduced MRPs. This procedure yielded reagents specific for MetO in these proteins, but proved to be ineffective in developing antibodies with broad MetO specificity. Conclusion Our data show that MRPs provide a convenient tool for characterization of Met oxidation, MetO reduction and Msr activities, and could be used for various aspects of redox biology involving reversible Met oxidation. PMID:23088625

  17. Crystal structure of the TLDc domain of oxidation resistance protein 2 from zebrafish.

    PubMed

    Blaise, Mickaël; Alsarraf, Husam M A B; Wong, Jaslyn E M M; Midtgaard, Søren Roi; Laroche, Fabrice; Schack, Lotte; Spaink, Herman; Stougaard, Jens; Thirup, Søren

    2012-06-01

    The oxidation resistance proteins (OXR) help to protect eukaryotes from reactive oxygen species. The sole C-terminal domain of the OXR, named TLDc is sufficient to perform this function. However, the mechanism by which oxidation resistance occurs is poorly understood. We present here the crystal structure of the TLDc domain of the oxidation resistance protein 2 from zebrafish. The structure was determined by X-ray crystallography to atomic resolution (0.97Å) and adopts an overall globular shape. Two antiparallel β-sheets form a central β-sandwich, surrounded by two helices and two one-turn helices. The fold shares low structural similarity to known structures. PMID:22434723

  18. Protein nanorings organized by poly(styrene-block-ethylene oxide) self-assembled thin films

    NASA Astrophysics Data System (ADS)

    Malmström, Jenny; Wason, Akshita; Roache, Fergus; Yewdall, N. Amy; Radjainia, Mazdak; Wei, Shanghai; Higgins, Michael J.; Williams, David E.; Gerrard, Juliet A.; Travas-Sejdic, Jadranka

    2015-11-01

    This study explores the use of block copolymer self-assembly to organize Lsmα, a protein which forms stable doughnut-shaped heptameric structures. Here, we have explored the idea that 2-D crystalline arrays of protein filaments can be prepared by stacking doughnut shaped Lsmα protein into the poly(ethylene oxide) blocks of a hexagonal microphase-separated polystyrene-b-polyethylene oxide (PS-b-PEO) block copolymer. We were able to demonstrate the coordinated assembly of such a complex hierarchical nanostructure. The key to success was the choice of solvent systems and protein functionalization that achieved sufficient compatibility whilst still promoting assembly. Unambiguous characterisation of these structures is difficult; however AFM and TEM measurements confirmed that the protein was sequestered into the PEO blocks. The use of a protein that assembles into stackable doughnuts offers the possibility of assembling nanoscale optical, magnetic and electronic structures.This study explores the use of block copolymer self-assembly to organize Lsmα, a protein which forms stable doughnut-shaped heptameric structures. Here, we have explored the idea that 2-D crystalline arrays of protein filaments can be prepared by stacking doughnut shaped Lsmα protein into the poly(ethylene oxide) blocks of a hexagonal microphase-separated polystyrene-b-polyethylene oxide (PS-b-PEO) block copolymer. We were able to demonstrate the coordinated assembly of such a complex hierarchical nanostructure. The key to success was the choice of solvent systems and protein functionalization that achieved sufficient compatibility whilst still promoting assembly. Unambiguous characterisation of these structures is difficult; however AFM and TEM measurements confirmed that the protein was sequestered into the PEO blocks. The use of a protein that assembles into stackable doughnuts offers the possibility of assembling nanoscale optical, magnetic and electronic structures. Electronic supplementary

  19. Advanced glycation end products impair function of late endothelial progenitor cells through effects on protein kinase Akt and cyclooxygenase-2

    SciTech Connect

    Chen Qin; Dong Li; Wang Lian; Kang Lina; Xu Biao

    2009-04-03

    Endothelial progenitor cells (EPCs) exhibit impaired function in the context of diabetes, and advanced glycation end products (AGEs), which accumulate in diabetes, may contribute to this. In the present study, we investigated the mechanism by which AGEs impair late EPC function. EPCs from human umbilical cord blood were isolated, and incubated with AGE-modified albumin (AGE-albumin) at different concentrations found physiologically in plasma. Apoptosis, migration, and tube formation assays were used to evaluate EPC function including capacity for vasculogenesis, and expression of the receptor for AGEs (RAGE), Akt, endothelial nitric oxide synthase (eNOS), and cycloxygenase-2 (COX-2) were determined. Anti-RAGE antibody was used to block RAGE function. AGE-albumin concentration-dependently enhanced apoptosis and depressed migration and tube formation, but did not affect proliferation, of late EPCs. High AGE-albumin increased RAGE mRNA and protein expression, and decreased Akt and COX-2 protein expression, whilst having no effect on eNOS mRNA or protein in these cells. These effects were inhibited by co-incubation with anti-RAGE antibody. These results suggest that RAGE mediates the AGE-induced impairment of late EPC function, through down-regulation of Akt and COX-2 in these cells.

  20. Development of microbial spoilage and lipid and protein oxidation in rabbit meat.

    PubMed

    Nakyinsige, K; Sazili, A Q; Aghwan, Z A; Zulkifli, I; Goh, Y M; Abu Bakar, F; Sarah, S A

    2015-10-01

    This experiment aimed to determine microbial spoilage and lipid and protein oxidation during aerobic refrigerated (4°C) storage of rabbit meat. Forty male New Zealand white rabbits were slaughtered according to the Halal slaughter procedure. The hind limbs were used for microbial analysis while the Longissimus lumborum m. was used for determination of lipid and protein oxidation. Bacterial counts generally increased with aging time and the limit for fresh meat (10(8)cfu/g) was reached at d 7 postmortem. Significant differences in malondialdehyde content were observed after 3d of storage. The thiol concentration significantly decreased with increase in aging time. The band intensities of myosin heavy chain and troponin T significantly reduced with increased refrigerated storage while actin remained relatively stable. This study thus proposes protein oxidation as a potential deteriorative change in refrigerated rabbit meat along with microbial spoilage and lipid oxidation. PMID:26115345

  1. Effects of postmortem delays on protein composition and oxidation.

    PubMed

    ElHajj, Zeinab; Cachot, Amélie; Müller, Terry; Riederer, Irène M; Riederer, Beat M

    2016-03-01

    Human autopsy brain tissue is widely used to study neurodegenerative diseases such as Alzheimer's, Parkinson's and other diseases. However, when it comes to an evaluation of data obtained from such tissue, it is essential to consider potential postmortem effects on protein composition, posttranslational modification and proteolysis with increasing postmortem delays. In this study, we analyzed mouse brain tissues with different postmortem delays (pmd) of 0 h, 6h and 24h, for changes in protein composition, proteolysis and modifications such as S-nitrosylation, carbonylation and ubiquitination. Proteins involved in Alzheimer's disease (AD) were of special interest, including cytoskeletal and synaptic proteins or proteins involved in inflammation. Several proteins were fairly resistant to degradation during the first 6h but started to degrade thereafter. S-nitrosylation and carbonylation showed not much variation, except for those proteins that were susceptible to degradation. Brain spectrin was S-nitrosylated at death, and S-nitrosylated degradation fragments were measured at a pmd of 24h, indicating a susceptibility of brain spectrin to degradation. Furthermore, the physiological role of S-nitrosylation remains to be investigated. When studying human brain tissue, some proteins are more susceptible to degradation than others, while ubiquitination and carbonylation were little affected during the first 24h after death. PMID:26791740

  2. Advances in Instrumentation for Quantification of Isotopic Nitrous Oxide from ppb levels to 100%

    NASA Astrophysics Data System (ADS)

    Dong, F.; Gupta, M.; Leen, J.; Provencal, R. A.; Owano, T. G.; Baer, D. S.

    2013-12-01

    The isotopic composition of trace gases provides information of their origin and fate that cannot be determined from their concentration measurements alone. Biological source and loss processes, like bacterial production of nitrous oxide, are typically accompanied by isotopic selectivity associated with the kinetics of bond formation and destruction. Of the three important biologically mediated greenhouse gases (CO2, CH4 and N2O), the understanding of nitrous oxide isotopic budget in air lags behind the other two gases primarily due to the relatively low concentration of N2O in ambient air (~320 ppb). Furthermore, the origin of nitrates in rivers, lakes, ocean and other water supplies may be determined from analyses of isotopic nitrous oxide produced via chemical reduction or biological conversion. These processes can produce nitrous oxide at levels considerably greater than those present in ambient air. To date, analyses of isotopic nitrous oxide requires either pre-concentration of samples containing low concentrations or dilution of samples with high concentrations. We report significant advances of instrumentation for real-time measurements of site-specific isotopic nitrogen (δ15Nα, δ15Nβ, δ15N, δ18O) and mixing ratio [N2O] of nitrous oxide over a very wide range of mole fractions in air. Specifically, LGR's Isotopic N2O Analyzer can report site-specific isotopic nitrogen and isotopic oxygen continuously in flows ranging from 0.2 to over 20 ppm (parts per million) nitrous oxide in air (with preconcentration or dilution). Furthermore, for samples of limited volume, a batch technique may be used for similar isotopic measurements in discrete samples containing 0.2 ppm to 100% nitrous oxide (e.g., sample volumes from bacterial digestion can be as little as 1-10 mL). This novel technology, which employs cavity enhanced absorption spectroscopy (Off-Axis ICOS) and a mid-infrared laser (4.56 microns) and does not require any cryogenic components, has been

  3. Effects of oxidative modification on thermal aggregation and gel properties of soy protein by malondialdehyde.

    PubMed

    Wu, Wei; Hua, Yufei; Lin, Qinlu

    2014-03-01

    Malondialdehyde (MDA) was selected as a representative of lipid peroxidation products to investigate the effects of oxidative modification on thermal aggregation and gel properties of soy protein by lipid peroxidation products. Incubation of soy protein with increasing concentration of MDA resulted in gradual decrease of particle size and content of thermal aggregates during heat denaturation. Oxidative modification by MDA resulted in a decrease in water holding capacity, gel hardness, and gel strength of soy protein gel. An increase in coarseness and interstice of MDA modified protein gel network was accompanied by uneven distribution of interstice as MDA concentration increased. The results showed that degree of thermal aggregation of MDA-modified soy protein gradually decreased as MDA concentration increased, which contributed to a decrease in water holding capacity, gel hardness, and gel strength of MDA-modified soy protein gel. PMID:24587523

  4. [The oxidative modification of blood plasma proteins in patients in critical states].

    PubMed

    Riabov, G A; Azizov, Iu M; Dorokhov, S I; Kulabukhov, V V; Titova, I A; Pasechnik, I N; Brazhnik, T B; Rybintsev, V Iu

    2000-01-01

    Current concepts on the formation and biological activity of activated oxygen forms (AOF) in humans are discussed. The main AOF types are produced as a result of consecutive single-electron recovery of molecular oxygen (O2) and are more reactive than O2. AOF are initially normal components of cellular metabolism with certain biological functions. Their reactive aggressiveness is regulated by a potent antioxidant system which is present in any live organism. In disease this balance is distorted towards uncontrolled AOF generation and formation of oxidative stress, when AOF impair all biological structures, including proteins. Unregulated modification of proteins by AOF results in loss of protein biological activities (enzymatic, receptor, transporting function, etc.). Moreover, oxidative modification of proteins generates new antigens and provokes immune response. The authors present experimental data which confirm significant modification of plasma proteins in critical patients. The role of the detrimental effect of AOF on proteins in the formation of critical states deserves special studies. PMID:10833843

  5. An immunochemical approach to detect oxidized protein tyrosine phosphatases using a selective C-nucleophile tag.

    PubMed

    Garcia, Francisco J; Carroll, Kate S

    2016-05-24

    Protein tyrosine phosphatases are crucial regulators of signal transduction and function as antagonists towards protein tyrosine kinases to control reversible tyrosine phosphorylation, thereby regulating fundamental physiological processes. Growing evidence has supported the notion that reversible oxidative inactivation of the catalytic cysteine residue in protein tyrosine phosphatases serves as an oxidative post-translational modification that regulates its activity to influence downstream signaling by promoting phosphorylation and induction of the signaling cascade. The oxidation of cysteine to the sulfenic acid is often transient and difficult to detect, thus making it problematic in understanding the role that this oxidative post-translational modification plays in redox-biology and pathogenesis. Several methods to detect cysteine oxidation in biological systems have been developed, though targeted approaches to directly detect oxidized phosphatases are still lacking. Herein we describe the development of a novel immunochemical approach to directly profile oxidized phosphatases. This immunochemical approach consists of an antibody designed to recognize the conserved sequence of the PTP active site (VHCDMDSAG) harboring the catalytic cysteine modified with dimedone (CDMD), a nucleophile that chemoselectively reacts with cysteine sulfenic acids to form a stable thioether adduct. Additionally, we provide biochemical and mass spectrometry workflows to be used in conjugation with this newly developed immunochemical approach to assist in the identification and quantification of basal and oxidized phosphatases. PMID:26757830

  6. New insights into the effects of the protein moiety of oxidized LDL (oxLDL).

    PubMed

    Vicca, Stéphanie; Massy, Ziad A; Hennequin, Carole; Rihane, Djamel; Nguyen-Khoa, Thao; Drüeke, Tilman B; Lacour, Bernard

    2003-05-01

    Oxidative stress has been implicated in the cardiovascular complications in chronic renal failure patients. Lipoprotein oxidation is involved in the genesis of atherosclerosis. Both the lipid and the protein moieties of low-density lipoproteins (LDL) are subject to oxidation. We have shown that oxidation of LDL by hypochlorous acid (HOCl) in vitro, reflecting increased myeloperoxidase (MPO) activity in vivo, leads mainly to modifications of apolipoproteins, such that the latter in turn induce high rates of apoptosis in a human monocytic cell line via a caspase-dependent pathway. These in vitro oxidative changes of LDL protein moiety, if shown to occur to a significant extent in uremic patients in vivo, may represent an important pathway in the pathogenesis of atherogenesis. PMID:12694326

  7. Development of Enantioselective Polyclonal Antibodies to Detect Styrene Oxide Protein Adducts

    PubMed Central

    Shen, Shuijie; Zhang, Fan; Zeng, Su; Tian, Ye; Chai, Xiaojuan; Gee, Shirley; Hammock, Bruce D.; Zheng, Jiang

    2012-01-01

    Styrene has been reported to be pneumotoxic and hepatotoxic in humans and animals. Styrene oxide, a major reactive metabolite of styrene, has been found to form covalent binding with proteins, such as albumin and hemoglobin. Styrene oxide has two optical isomers and it was reported that the (R)-enantiomer was more toxic than the (S)-enantiomer. The purpose of this study was to develop polyclonal antibodies that can stereoselectively recognize proteins modified by styrene oxide enantiomers at cysteine residues. Immunogens were prepared by alkylation of thiolated keyhole limpet hemocyanin (KLH) with styrene oxide enantiomers. Polyclonal antibodies were raised by immunization of rabbits with the chiral immunogens. Titration tests showed all six rabbits generated high titers of antisera that recognize (R)- or (S)-coating antigens accordingly. No cross-reaction was observed toward the carrier protein (BSA). All three rabbits immunized with (R)-immunogen produced antibodies that show enantioselectivity to the corresponding antigen, while only one among the three rabbits immunized with (S)-immunogen generated antibodies with enantioselectivity of the recognition. The enantioselectivity was also observed in competitive ELISA and immunoblot analysis. Additionally, competitive ELISA tests showed that the immunorecognition required the hydroxyl group of the haptens. Immunoblot analysis demonstrated that the immunorecognition depended on the amount of protein adducts blotted and hapten loading in protein adducts. In summary, we successfully developed polyclonal antibodies to stereoselectively detect protein adducts modified by styrene oxide enantiomers. PMID:19245253

  8. Application of electrochemical advanced oxidation processes to the mineralization of the herbicide diuron.

    PubMed

    Pipi, Angelo R F; Sirés, Ignasi; De Andrade, Adalgisa R; Brillas, Enric

    2014-08-01

    Here, solutions with 0.185mM of the herbicide diuron of pH 3.0 have been treated by electrochemical advanced oxidation processes (EAOPs) like electrochemical oxidation with electrogenerated H2O2 (EO-H2O2), electro-Fenton (EF) and UVA photoelectro-Fenton (PEF) or solar PEF (SPEF). Trials were performed in stirred tank reactors of 100mL and in a recirculation flow plant of 2.5L using a filter-press reactor with a Pt or boron-doped diamond (BDD) anode and an air-diffusion cathode for H2O2 electrogeneration. Oxidant hydroxyl radicals were formed from water oxidation at the anode and/or in the bulk from Fenton's reaction between added Fe(2+) and generated H2O2. In both systems, the relative oxidation ability of the EAOPs increased in the sequence EO-H2O2

  9. Chemical oxygen demand reduction in coffee wastewater through chemical flocculation and advanced oxidation processes.

    PubMed

    Zayas Pérez, Teresa; Geissler, Gunther; Hernandez, Fernando

    2007-01-01

    The removal of the natural organic matter present in coffee processing wastewater through chemical coagulation-flocculation and advanced oxidation processes (AOP) had been studied. The effectiveness of the removal of natural organic matter using commercial flocculants and UV/H2O2, UV/O3 and UV/H2O2/O3 processes was determined under acidic conditions. For each of these processes, different operational conditions were explored to optimize the treatment efficiency of the coffee wastewater. Coffee wastewater is characterized by a high chemical oxygen demand (COD) and low total suspended solids. The outcomes of coffee wastewater treatment using coagulation-flocculation and photodegradation processes were assessed in terms of reduction of COD, color, and turbidity. It was found that a reduction in COD of 67% could be realized when the coffee wastewater was treated by chemical coagulation-flocculation with lime and coagulant T-1. When coffee wastewater was treated by coagulation-flocculation in combination with UV/H2O2, a COD reduction of 86% was achieved, although only after prolonged UV irradiation. Of the three advanced oxidation processes considered, UV/H2O2, UV/O3 and UV/H2O2/O3, we found that the treatment with UV/H2O2/O3 was the most effective, with an efficiency of color, turbidity and further COD removal of 87%, when applied to the flocculated coffee wastewater. PMID:17918591

  10. Degradation of estrone in water and wastewater by various advanced oxidation processes.

    PubMed

    Sarkar, Shubhajit; Ali, Sura; Rehmann, Lars; Nakhla, George; Ray, Madhumita B

    2014-08-15

    A comprehensive study was conducted to determine the relative efficacy of various advanced oxidation processes such as O3, H2O2, UV, and combinations of UV/O3, UV/H2O2 for the removal of estrone (E1) from pure water and secondary effluent. In addition to the parent compound (E1) removal, performance of the advanced oxidation processes was characterized using removal of total organic carbon (TOC), and estrogenicity of the effluent. Although E1 removal was high for all the AOPs, intermediates formed were more difficult to degrade leading to slow TOC removal. Energy calculations and cost analysis indicated that, although UV processes have low electricity cost, ozonation is the least cost option ($ 0.34/1000 gallons) when both capital and operating costs were taken into account. Ozonation also is superior to the other tested AOPs due to higher removal of TOC and estrogenicity. The rate of E1 removal decreased linearly with the background TOC in water, however, E1 degradation in the secondary effluent from a local wastewater treatment plant was not affected significantly due to the low COD values in the effluent. PMID:24937659

  11. Treatment of coking wastewater by an advanced Fenton oxidation process using iron powder and hydrogen peroxide.

    PubMed

    Chu, Libing; Wang, Jianlong; Dong, Jing; Liu, Haiyang; Sun, Xulin

    2012-01-01

    In this study the treatment of coking wastewater was investigated by an advanced Fenton oxidation process using iron powder and hydrogen peroxide. Particular attention was paid to the effect of initial pH, dosage of H(2)O(2) and to improvement in biodegradation. The results showed that higher COD and total phenol removal rates were achieved with a decrease in initial pH and an increase in H(2)O(2) dosage. At an initial pH of less than 6.5 and H(2)O(2) concentration of 0.3 M, COD removal reached 44-50% and approximately 95% of total phenol removal was achieved at a reaction time of 1 h. The oxygen uptake rate of the effluent measured at a reaction time of 1h increased by approximately 65% compared to that of the raw coking wastewater. This indicated that biodegradation of the coking wastewater was significantly improved. Several organic compounds, including bifuran, quinoline, resorcinol and benzofuranol were removed completely as determined by GC-MS analysis. The advanced Fenton oxidation process is an effective pretreatment method for the removal of organic pollutants from coking wastewater. This process increases biodegradation, and may be combined with a classical biological process to achieve effluent of high quality. PMID:22014660

  12. Electrochemical advanced oxidation and biological processes for wastewater treatment: a review of the combined approaches.

    PubMed

    Ganzenko, Oleksandra; Huguenot, David; van Hullebusch, Eric D; Esposito, Giovanni; Oturan, Mehmet A

    2014-01-01

    As pollution becomes one of the biggest environmental challenges of the twenty-first century, pollution of water threatens the very existence of humanity, making immediate action a priority. The most persistent and hazardous pollutants come from industrial and agricultural activities; therefore, effective treatment of this wastewater prior to discharge into the natural environment is the solution. Advanced oxidation processes (AOPs) have caused increased interest due to their ability to degrade hazardous substances in contrast to other methods, which mainly only transfer pollution from wastewater to sludge, a membrane filter, or an adsorbent. Among a great variety of different AOPs, a group of electrochemical advanced oxidation processes (EAOPs), including electro-Fenton, is emerging as an environmental-friendly and effective treatment process for the destruction of persistent hazardous contaminants. The only concern that slows down a large-scale implementation is energy consumption and related investment and operational costs. A combination of EAOPs with biological treatment is an interesting solution. In such a synergetic way, removal efficiency is maximized, while minimizing operational costs. The goal of this review is to present cutting-edge research for treatment of three common and problematic pollutants and effluents: dyes and textile wastewater, olive processing wastewater, and pharmaceuticals and hospital wastewater. Each of these types is regarded in terms of recent scientific research on individual electrochemical, individual biological and a combined synergetic treatment. PMID:24965093

  13. Oxidation of specific SH protein of mitochondria by photodynamic action of hematoporphyrin. Relevance to uncoupling of oxidative phosphorylation.

    PubMed

    Yamamoto, K; Kawanishi, S

    1991-08-01

    Photoexcited hematoporphyrin (Hp) induces the uncoupling of oxidative phosphorylation of mitochondria. The uncoupling was inhibited by pre-incubation of mitochondria with a fluorescent SH reagent, eosin-5-maleimide, which has been shown to react specifically with an essential SH group of the Pi/H+ symporter [Houstek and Pedersen, J Biol Chem 260: 6288-6295, 1985]. Eosin-5-maleimide labeled 33, 34.5 and 36 kDa proteins in untreated rat liver mitochondria. When eosin-5-maleimide was added after the treatment with Hp plus light, the proteins were not labeled. Singlet oxygen detection by the ESR spin trapping method during photoradiation of Hp was inhibited by amino acids. Cysteine inhibited it more efficiently than histidine, methionine, tryptophan, tyrosine or alanine under the conditions used. HPLC demonstrated that Hp plus light oxidizes cysteine to cystine together with a smaller amount of cysteinesulfinic acid. These results suggest that Hp plus light oxidizes the SH group of mitochondrial protein, probably the Pi/H+ symporter, with singlet oxygen as a mediator. The possibility of the uncoupling of oxidative phosphorylation through such a modification of the Pi/H+ symporter is discussed. PMID:1714732

  14. Heterologous Expression and Characterization of the Manganese-Oxidizing Protein from Erythrobacter sp. Strain SD21

    PubMed Central

    Nakama, Katherine; Medina, Michael; Lien, Ahn; Ruggieri, Jordan; Collins, Krystle

    2014-01-01

    The manganese (Mn)-oxidizing protein (MopA) from Erythrobacter sp. strain SD21 is part of a unique enzymatic family that is capable of oxidizing soluble Mn(II). This enzyme contains two domains, an animal heme peroxidase domain, which contains the catalytic site, followed by a C-terminal calcium binding domain. Different from the bacterial Mn-oxidizing multicopper oxidase enzymes, little is known about MopA. To gain a better understanding of MopA and its role in Mn(II) oxidation, the 238-kDa full-length protein and a 105-kDa truncated protein containing only the animal heme peroxidase domain were cloned and heterologously expressed in Escherichia coli. Despite having sequence similarity to a peroxidase, hydrogen peroxide did not stimulate activity, nor was activity significantly decreased in the presence of catalase. Both pyrroloquinoline quinone (PQQ) and hemin increased Mn-oxidizing activity, and calcium was required. The Km for Mn(II) of the full-length protein in cell extract was similar to that of the natively expressed protein, but the Km value for the truncated protein in cell extract was approximately 6-fold higher than that of the full-length protein, suggesting that the calcium binding domain may aid in binding Mn(II). Characterization of the heterologously expressed MopA has provided additional insight into the mechanism of bacterial Mn(II) oxidation, which will aid in understanding the role of MopA and Mn oxidation in bioremediation and biogeochemical cycling. PMID:25172859

  15. Heterologous expression and characterization of the manganese-oxidizing protein from Erythrobacter sp. strain SD21.

    PubMed

    Nakama, Katherine; Medina, Michael; Lien, Ahn; Ruggieri, Jordan; Collins, Krystle; Johnson, Hope A

    2014-11-01

    The manganese (Mn)-oxidizing protein (MopA) from Erythrobacter sp. strain SD21 is part of a unique enzymatic family that is capable of oxidizing soluble Mn(II). This enzyme contains two domains, an animal heme peroxidase domain, which contains the catalytic site, followed by a C-terminal calcium binding domain. Different from the bacterial Mn-oxidizing multicopper oxidase enzymes, little is known about MopA. To gain a better understanding of MopA and its role in Mn(II) oxidation, the 238-kDa full-length protein and a 105-kDa truncated protein containing only the animal heme peroxidase domain were cloned and heterologously expressed in Escherichia coli. Despite having sequence similarity to a peroxidase, hydrogen peroxide did not stimulate activity, nor was activity significantly decreased in the presence of catalase. Both pyrroloquinoline quinone (PQQ) and hemin increased Mn-oxidizing activity, and calcium was required. The Km for Mn(II) of the full-length protein in cell extract was similar to that of the natively expressed protein, but the Km value for the truncated protein in cell extract was approximately 6-fold higher than that of the full-length protein, suggesting that the calcium binding domain may aid in binding Mn(II). Characterization of the heterologously expressed MopA has provided additional insight into the mechanism of bacterial Mn(II) oxidation, which will aid in understanding the role of MopA and Mn oxidation in bioremediation and biogeochemical cycling. PMID:25172859

  16. Insulin-like growth factor I stimulates lipid oxidation, reduces protein oxidation, and enhances insulin sensitivity in humans.

    PubMed Central

    Hussain, M A; Schmitz, O; Mengel, A; Keller, A; Christiansen, J S; Zapf, J; Froesch, E R

    1993-01-01

    To elucidate the effects of insulin-like growth factor I (IGF-I) on fuel oxidation and insulin sensitivity, eight healthy subjects were treated with saline and recombinant human (IGF-I (10 micrograms/kg.h) during 5 d in a crossover, randomized fashion, while receiving an isocaloric diet (30 kcal/kg.d) throughout the study period. On the third and fourth treatment days, respectively, an L-arginine stimulation test and an intravenous glucose tolerance test were performed. A euglycemic, hyperinsulinemic clamp combined with indirect calorimetry and a glucose tracer infusion were performed on the fifth treatment day. IGF-I treatment led to reduced fasting and stimulated (glucose and/or L-arginine) insulin and growth hormone secretion. Basal and stimulated glucagon secretion remained unchanged. Intravenous glucose tolerance was unaltered despite reduced insulin secretion. Resting energy expenditure and lipid oxidation were both elevated, while protein oxidation was reduced, and glucose turnover rates were unaltered on the fifth treatment day with IGF-I as compared to the control period. Enhanced lipolysis was reflected by elevated circulating free fatty acids. Moreover, insulin-stimulated oxidative and nonoxidative glucose disposal (i.e., insulin sensitivity) were enhanced during IGF-I treatment. Thus, IGF-I treatment leads to marked changes in lipid and protein oxidation, whereas, at the dose used, carbohydrate metabolism remains unaltered in the face of reduced insulin levels and enhanced insulin sensitivity. Images PMID:8227340

  17. Triage of oxidation-prone proteins by Sqstm1/p62 within the mitochondria

    SciTech Connect

    Lee, Minjung; Shin, Jaekyoon

    2011-09-16

    Highlights: {yields} The mitochondrion contains its own protein quality control system. {yields} p62 localizes within the mitochondria and forms mega-dalton sized complexes. {yields} p62 interacts with oxidation-prone proteins and the proteins of quality control. {yields} In vitro delivery of p62 improves mitochondrial functions. {yields} p62 is implicated as a participant in mitochondrial protein quality control. -- Abstract: As the mitochondrion is vulnerable to oxidative stress, cells have evolved several strategies to maintain mitochondrial integrity, including mitochondrial protein quality control mechanisms and autophagic removal of damaged mitochondria. Involvement of an autophagy adaptor, Sqstm1/p62, in the latter process has been recently described. In the present study, we provide evidence that a portion of p62 directly localizes within the mitochondria and supports stable electron transport by forming heterogeneous protein complexes. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF) of mitochondrial proteins co-purified with p62 revealed that p62 interacts with several oxidation-prone proteins, including a few components of the electron transport chain complexes, as well as multiple chaperone molecules and redox regulatory enzymes. Accordingly, p62-deficient mitochondria exhibited compromised electron transport, and the compromised function was partially restored by in vitro delivery of p62. These results suggest that p62 plays an additional role in maintaining mitochondrial integrity at the vicinity of target machineries through its function in relation to protein quality control.

  18. Advanced negative detection method comparable to silver stain for SDS-PAGE separated proteins detection.

    PubMed

    Wang, Xu; Hwang, Sun-Young; Cong, Wei-Tao; Jin, Li-Tai; Choi, Jung-Kap

    2016-10-01

    In order to achieve an easy, rapid and sensitive protocol to detect proteins in polyacrylamide gel, an advanced negative detection method comparable to silver stain is described. When a gel was incubated with Phloxine B and followed by the development in acidic solution, the zones where forming protein-dye complex were selectively transparent, unlike opaque gel background. Within 50 min after electrophoresis, down to 0.1-0.4 ng of gel-separated proteins (similar with silver stain) could be observed, without labor-intensive and time-consuming procedure. Comparing with the most common negative stain method, Imidazole-zinc stain, Phloxine B stain has been shown higher sensitivity and distinct contrast between the transparent protein bands/spots and opaque background than those; furthermore, it is no longer necessary to concern about retention time of observation. This technique may provide a sensitive and practical choice for proteomics researches. PMID:27430933

  19. Advanced glycation end products inhibit testosterone secretion by rat Leydig cells by inducing oxidative stress and endoplasmic reticulum stress.

    PubMed

    Zhao, Yun-Tao; Qi, Ya-Wei; Hu, Chuan-Yin; Chen, Shao-Hong; Liu, You

    2016-08-01

    Diabetes severely impairs male reproduction. The present study assessed the effects and mechanisms of action of advanced glycation end products (AGEs), which play an important role in the development of diabetes complications, on testosterone secretion by rat Leydig cells. Primary rat Leydig cells were cultured and treated with AGEs (25, 50, 100 and 200 µg/ml). Testosterone production induced by human chorionic gonadotropin (hCG) was determined by ELISA. The mRNA and protein expression levels of steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (P450scc) and 3β-hydroxysteroid dehydrogenase (3β-HSD), which are involved in testosterone biosynthesis, were measured by reverse transcription-quantitative PCR and western blot analyssi, respectively. Reactive oxygen species (ROS) production in Leydig cells was measured using the dichlorofluorescein diacetate (DCFH-DA) probe. The expression levels of endoplasmic reticulum stress-related proteins [C/EBP homologous protein (CHOP) and glucose-regulated protein 78 (GRP78)] in the Leydig cells were measured by western blot analysis. We found that the AGEs markedly suppressed testosterone production by rat Leydig cells which was induced by hCG in a concentration-dependent manner compared with the control (P<0.01). The mRNA and protein expression levels of StAR, 3β-HSD and P450scc were downregulated by the AGEs in a dose-dependent manner compared with the control (P<0.01). The antioxidant agent, N-acetyl‑L‑cysteine (NAC), and the endoplasmic reticulum stress inhibitor, tauroursodeoxycholic acid (TUDCA), reversed the inhibitory effects of AGEs. In addition, the content of ROS in Leydig cells treated with AGEs increased significantly. The expression levels of CHOP and GRP78 were markedly upregulated by the AGEs in the Leydig cells. From these findings, it can be concluded that AGEs inhibit testosterone production by rat Leydig cells by inducing oxidative stress and

  20. Study of solid oxide fuel cell interconnects, protective coatings and advanced physical vapor deposition techniques

    NASA Astrophysics Data System (ADS)

    Gannon, Paul Edward

    High energy conversion efficiency, decreased environmentally-sensitive emissions and fuel flexibility have attracted increasing attention toward solid oxide fuel cell (SOFC) systems for stationary, transportation and portable power generation. Critical durability and cost issues, however, continue to impede wide-spread deployment. Many intermediate temperature (600-800°C) planar SOFC systems employ metallic alloy interconnect components, which physically connect individual fuel cells into electric series, facilitate gas distribution to appropriate SOFC electrode chambers (fuel/anode and oxidant[air]/cathode) and provide SOFC stack mechanical support. These demanding multifunctional requirements challenge commercially-available and inexpensive metallic alloys due to corrosion and related effects. Many ongoing investigations are aimed at enabling inexpensive metallic alloys (via bulk and/or surface modifications) as SOFC interconnects (SOFC(IC)s). In this study, two advanced physical vapor deposition (PVD) techniques: large area filtered vacuum arc deposition (LAFAD), and filtered arc plasma-assisted electron beam PVD (FA-EBPVD) were used to deposit a wide-variety of protective nanocomposite (amorphous/nanocrystalline) ceramic thin-film (<5microm) coatings on commercial and specialty stainless steels with different surface finishes. Both bare and coated steel specimens were subjected to SOFC(IC)-relevant exposures and evaluated using complimentary surface analysis techniques. Significant improvements were observed under simulated SOFC(IC) exposures with many coated specimens at ˜800°C relative to uncoated specimens: stable surface morphology; low area specific resistance (ASR <100mO·cm 2 >1,000 hours); and, dramatically reduced Cr volatility (>30-fold). Analyses and discussions of SOFC(IC) corrosion, advanced PVD processes and protective coating behavior are intended to advance understanding and accelerate the development of durable and commercially-viable SOFC

  1. Toxicological and chemical assessment of arsenic-contaminated groundwater after electrochemical and advanced oxidation treatments.

    PubMed

    Radić, Sandra; Crnojević, Helena; Vujčić, Valerija; Gajski, Goran; Gerić, Marko; Cvetković, Želimira; Petra, Cvjetko; Garaj-Vrhovac, Vera; Oreščanin, Višnja

    2016-02-01

    Owing to its proven toxicity and mutagenicity, arsenic is regarded a principal pollutant in water used for drinking. The objective of this study was the toxicological and chemical evaluation of groundwater samples obtained from arsenic enriched drinking water wells before and after electrochemical and ozone-UV-H2O2-based advanced oxidation processes (EAOP). For this purpose, acute toxicity test with Daphnia magna and chronic toxicity test with Lemna minor L. were employed as well as in vitro bioassays using human peripheral blood lymphocytes (HPBLs). Several oxidative stress parameters were estimated in L.minor. Physicochemical analysis showed that EAOP treatment was highly efficient in arsenic but also in ammonia and organic compound removal from contaminated groundwater. Untreated groundwater caused only slight toxicity to HPBLs and D. magna in acute experiments. However, 7-day exposure of L. minor to raw groundwater elicited genotoxicity, a significant growth inhibition and oxidative stress injury. The observed genotoxicity and toxicity of raw groundwater samples was almost completely eliminated by EAOP treatment. Generally, the results obtained with L. minor were in agreement with those obtained in the chemical analysis suggesting the sensitivity of the model organism in monitoring of arsenic-contaminated groundwater. In parallel to chemical analysis, the implementation of chronic toxicity bioassays in a battery is recommended in the assessment of the toxic and genotoxic potential of such complex mixtures. PMID:26580737

  2. Inactivation of Pseudomonas aeruginosa in electrochemical advanced oxidation process with diamond electrodes.

    PubMed

    Griessler, M; Knetsch, S; Schimpf, E; Schmidhuber, A; Schrammel, B; Wesner, W; Sommer, R; Kirschner, A K T

    2011-01-01

    The electrochemical advanced oxidation process (EAOP) with diamond electrodes may serve as an additional technology to the currently approved methods for water disinfection. Only few data exist on the microbicidal effect of the EAOP. The aim of our study was to investigate the microbicidal effect of a flow-through oxidation cell with diamond electrodes, using Pseudomonas aeruginosa as the test organism. Without electrical current the EAOP had no measurable effect on investigated microbiological and chemical parameters. For direct electrical current a stronger impact was observed at low flow rate than at higher flow rate. Depending on the contact time of the oxidants and the type of quenching reagent added, inactivation of P. aeruginosa was in the range log 1.6-3.6 at the higher flow rate and log 2.4-4.4 at the lower rate. Direct electrical current showed a stronger microbicidal effect than alternating current (maximum reduction log 4.0 and log 2.9, respectively). The microbiological results of experiments with this EAOP prototype revealed higher standard deviations than expected, based on our experience with standard water disinfection methods. Safe use of an EAOP system requires operating parameters to be defined and used accurately, and thus specific monitoring tests must be developed. PMID:21902043

  3. Degradation of triketone herbicides, mesotrione and sulcotrione, using advanced oxidation processes.

    PubMed

    Jović, Milica; Manojlović, Dragan; Stanković, Dalibor; Dojčinović, Biljana; Obradović, Bratislav; Gašić, Uroš; Roglić, Goran

    2013-09-15

    Degradation of two triketone herbicides, mesotrione and sulcotrione, was studied using four different advanced oxidation processes (AOPs): ozonization, dielectric barrier discharge (DBD reactor), photocatalysis and Fenton reagent, in order to find differences in mechanism of degradation. Degradation products were identified by high performance liquid chromatography (HPLC-DAD) and UHPLC-Orbitrap-MS analyses. A simple mechanism of degradation for different AOP was proposed. Thirteen products were identified during all degradations for both pesticides. It was assumed that the oxidation mechanisms in the all four technologies were not based only on the production and use of the hydroxyl radical, but they also included other kinds of oxidation mechanisms specific for each technology. Similarity was observed between degradation mechanism of ozonation and DBD. The greatest difference in the products was found in Fenton degradation which included the opening of benzene ring. When degraded with same AOP pesticides gave at the end of treatment the same products. Global toxicity and COD value of samples was determined after all degradations. Real water sample was used to study influence of organic matter on pesticide degradation. These results could lead to accurate estimates of the overall effects of triketone herbicides on environmental ecosystems and also contributed to the development of improved removal processes. PMID:23892174

  4. BENZENE OXIDE PROTEIN ADDUCTS AS BIOMARKERS OF BENZENE EXPOSURE

    EPA Science Inventory

    Benzene is known to be hematotoxic and carcinogenic in animals and humans. While metabolism is required for toxicity, the identity of the ultimate carcinogen(s) remains unknown. Benzene oxide (BO) is the first and most abundant of the metabolites, but very little is known about...

  5. Multifunctional Delivery Systems for Advanced oral Uptake of Peptide/Protein Drugs.

    PubMed

    Park, Jin Woo; Kim, Sun Jin; Kwag, Dong Sup; Kim, Sol; Park, Jeyoung; Youn, Yu Seok; Bae, You Han; Lee, Eun Seong

    2015-01-01

    In recent years, advances in biotechnology and protein engineering have enabled the production of large quantities of proteins and peptides as important therapeutic agents. Various researchers have used biocompatible functional polymers to prepare oral dosage forms of proteins and peptides for chronic use and for easier administration to enhance patient compliance. However, there is a need to enhance their safety and effectiveness further. Most macromolecules undergo severe denaturation at low pH and enzymatic degradation in the gastrointestinal tract. The macromolecules' large molecular size and low lipophilicity cause low permeation through the intestinal membrane. The major strategies that have been used to overcome these challenges (in oral drug carrier systems) can be classified as follows: enteric coating or encapsulation with pH-sensitive polymers or mucoadhesive polymers, co-administration of protease inhibitors, incorporation of absorption enhancers, modification of the physicochemical properties of the macromolecules, and site-specific delivery to the colon. This review attempts to summarize the various advanced oral delivery carriers, including nanoparticles, lipid carriers, such as liposomes, nano-aggregates using amphiphilic polymers, complex coacervation of oppositely charged polyelectrolytes, and inorganic porous particles. The particles were formulated and/or surface modified with functional polysaccharides or synthetic polymers to improve oral bioavailability of proteins and peptides. We also discuss formulation strategies to overcome barriers, therapeutic efficacies in vivo, and potential benefits and issues for successful oral dosage forms of the proteins and peptides. PMID:26027575

  6. Enhanced lipid oxidation by oxidatively modified myoglobin: role of protein-bound heme.

    PubMed

    Vuletich, J L; Osawa, Y; Aviram, M

    2000-03-24

    The formation of oxidized low density lipoprotein (LDL) is believed to play a significant role in the pathogenesis of atherosclerosis. Myoglobin in the presence of H(2)O(2) has been shown to catalyze LDL oxidation in vitro. It is established that an oxidatively altered form of myoglobin (Mb-H), which contains a prosthetic heme covalently crosslinked to the apoprotein, is a major product in the reaction of native myoglobin with peroxides. In the current study, we have shown for the first time that Mb-H, in the absence of exogenously added peroxides, oxidizes LDL and purified lipids, as determined by the formation of conjugated dienes, lipid peroxides, and thiobarbituric acid reactive substances. Moreover, the rate of oxidation of pure phosphatidylcholine by Mb-H was found to be at least sevenfold greater than that observed for native myoglobin. The current study strongly suggests a role for Mb-H in the lipid peroxidation observed with myoglobin. PMID:10720470

  7. Protein Phosphatase 2A Mediates Oxidative Stress Induced Apoptosis in Osteoblasts.

    PubMed

    Huang, Chong-xin; Lv, Bo; Wang, Yue

    2015-01-01

    Osteoporosis is one of the most common bone diseases, which is characterized by a systemic impairment of bone mass and fragility fractures. Age-related oxidative stress is highly associated with impaired osteoblastic dysfunctions and subsequent osteoporosis. In osteoblasts (bone formation cells), reactive oxygen species (ROS) are continuously generated and further cause lipid peroxidation, protein damage, and DNA lesions, leading to osteoblastic dysfunctions, dysdifferentiations, and apoptosis. Although much progress has been made, the mechanism responsible for oxidative stress induced cellular alternations and osteoblastic toxicity is still not fully elucidated. Here, we demonstrate that protein phosphatase 2A (PP2A), a major protein phosphatase in mammalian cells, mediates oxidative stress induced apoptosis in osteoblasts. Our results showed that lipid peroxidation products (4-HNE) may induce dramatic oxidative stress, inflammatory reactions, and apoptosis in osteoblasts. These oxidative stress responses may ectopically activate PP2A phosphatase activity, which may be mediated by inactivation of AKT/mTOR pathway. Moreover, inhibition of PP2A activity by okadaic acid might partly prevent osteoblastic apoptosis under oxidative conditions. These findings may reveal a novel mechanism to clarify the role of oxidative stress for osteoblastic apoptosis and provide new possibilities for the treatment of related bone diseases, such as osteoporosis. PMID:26538836

  8. Oxidative processes during enzymatic hydrolysis of cod protein and their influence on antioxidant and immunomodulating ability.

    PubMed

    Halldorsdottir, Sigrun M; Sveinsdottir, Holmfridur; Freysdottir, Jona; Kristinsson, Hordur G

    2014-01-01

    Fish protein hydrolysates (FPH) have many desirable properties, however heating and shifts in pH can cause oxidation during enzymatic hydrolysis. The objective was to investigate oxidative processes during enzymatic hydrolysis of fish protein and the impact of oxidation on the antioxidant and immunomodulating ability of FPH. Protease P "Amano" 6 was used to hydrolyze cod protein in the presence and absence of pro-oxidants at pH 8 and 36°C to achieve 20% degree of hydrolysis. Results from thiobarbituric acid reactive substances (TBARS) and sensory analysis indicate that oxidation can develop rapidly during hydrolysis. A cellular antioxidant assay using a HepG2 cell model indicated a negative impact of oxidation products on antioxidant properties of the FPH while results obtained in chemical assays showed a negligible impact. Results from a dendritic cell model indicating that oxidation products may affect anti-inflammatory activity in the body. This study provides important information regarding bioactive FPH. PMID:24001832

  9. Protein Phosphatase 2A Mediates Oxidative Stress Induced Apoptosis in Osteoblasts

    PubMed Central

    Huang, Chong-xin; Lv, Bo; Wang, Yue

    2015-01-01

    Osteoporosis is one of the most common bone diseases, which is characterized by a systemic impairment of bone mass and fragility fractures. Age-related oxidative stress is highly associated with impaired osteoblastic dysfunctions and subsequent osteoporosis. In osteoblasts (bone formation cells), reactive oxygen species (ROS) are continuously generated and further cause lipid peroxidation, protein damage, and DNA lesions, leading to osteoblastic dysfunctions, dysdifferentiations, and apoptosis. Although much progress has been made, the mechanism responsible for oxidative stress induced cellular alternations and osteoblastic toxicity is still not fully elucidated. Here, we demonstrate that protein phosphatase 2A (PP2A), a major protein phosphatase in mammalian cells, mediates oxidative stress induced apoptosis in osteoblasts. Our results showed that lipid peroxidation products (4-HNE) may induce dramatic oxidative stress, inflammatory reactions, and apoptosis in osteoblasts. These oxidative stress responses may ectopically activate PP2A phosphatase activity, which may be mediated by inactivation of AKT/mTOR pathway. Moreover, inhibition of PP2A activity by okadaic acid might partly prevent osteoblastic apoptosis under oxidative conditions. These findings may reveal a novel mechanism to clarify the role of oxidative stress for osteoblastic apoptosis and provide new possibilities for the treatment of related bone diseases, such as osteoporosis. PMID:26538836

  10. 17β-Estradiol alters oxidative damage and oxidative stress response protein expression in the mouse mammary gland.

    PubMed

    Yuan, Lisi; Dietrich, Alicia K; Ziegler, Yvonne S; Nardulli, Ann M

    2016-05-01

    Although substantial evidence has demonstrated that parity and 17β-estradiol (E2) reduce mammary carcinogenesis, it is not clear how this protection is conferred. Thus, we examined the effects of parity and E2 treatment in the mammary glands of ovariectomized 15 week-old virgin mice, 15 week-old primiparous mice, and 9 month-old retired breeders. E2 treatment significantly increased lipid peroxidation, protein carbonylation, and protein nitrosylation in the virgin mice, but not in the age-matched primiparous mice or retired breeders. Mammary gland expression of the oxidative stress response protein Cu/Zn superoxide dismutase was consistently reduced in all of the E2-treated mice regardless of parity. Expression of the oxidative stress and DNA repair protein apurinic endonuclease (Ape1) was significantly increased only in the mammary glands of the E2-treated retired breeders. These findings suggest that E2 and parity help to reduce mammary oncogenesis by maintaining the structure and function of proteins, lipids, and DNA. PMID:26872614

  11. The potential of protein-nanomaterial interaction for advanced drug delivery.

    PubMed

    Peng, Qiang; Mu, Huiling

    2016-03-10

    Nanomaterials, like nanoparticles, micelles, nano-sheets, nanotubes and quantum dots, have great potentials in biomedical fields. However, their delivery is highly limited by the formation of protein corona upon interaction with endogenous proteins. This new identity, instead of nanomaterial itself, would be the real substance the organs and cells firstly encounter. Consequently, the behavior of nanomaterials in vivo is uncontrollable and some undesired effects may occur, like rapid clearance from blood stream; risk of capillary blockage; loss of targeting capacity; and potential toxicity. Therefore, protein-nanomaterial interaction is a great challenge for nanomaterial systems and should be inhibited. However, this interaction can also be used to functionalize nanomaterials by forming a selected protein corona. Unlike other decoration using exogenous molecules, nanomaterials functionalized by selected protein corona using endogenous proteins would have greater promise for clinical use. In this review, we aim to provide a comprehensive understanding of protein-nanomaterial interaction. Importantly, a discussion about how to use such interaction is launched and some possible applications of such interaction for advanced drug delivery are presented. PMID:26812004

  12. Heart research advances using database search engines, Human Protein Atlas and the Sydney Heart Bank.

    PubMed

    Li, Amy; Estigoy, Colleen; Raftery, Mark; Cameron, Darryl; Odeberg, Jacob; Pontén, Fredrik; Lal, Sean; Dos Remedios, Cristobal G

    2013-10-01

    This Methodological Review is intended as a guide for research students who may have just discovered a human "novel" cardiac protein, but it may also help hard-pressed reviewers of journal submissions on a "novel" protein reported in an animal model of human heart failure. Whether you are an expert or not, you may know little or nothing about this particular protein of interest. In this review we provide a strategic guide on how to proceed. We ask: How do you discover what has been published (even in an abstract or research report) about this protein? Everyone knows how to undertake literature searches using PubMed and Medline but these are usually encyclopaedic, often producing long lists of papers, most of which are either irrelevant or only vaguely relevant to your query. Relatively few will be aware of more advanced search engines such as Google Scholar and even fewer will know about Quertle. Next, we provide a strategy for discovering if your "novel" protein is expressed in the normal, healthy human heart, and if it is, we show you how to investigate its subcellular location. This can usually be achieved by visiting the website "Human Protein Atlas" without doing a single experiment. Finally, we provide a pathway to discovering if your protein of interest changes its expression level with heart failure/disease or with ageing. PMID:23856366

  13. Protein and lipid oxidative damage in healthy students during and after exam stress.

    PubMed

    Nakhaee, Alireza; Shahabizadeh, Fatemeh; Erfani, Mozhgan

    2013-06-13

    Oxidative damage at cellular level is thought to be one of the mechanisms in the pathogenesis of psychological stress (anxiety). The aim of this study was to investigate lipid and protein oxidative damage in exam anxiety conditions. Blood samples were collected in two stages (during the exam period and post vacation) from 51 healthy female students after responding to Beck Anxiety Inventory (BAI) and test anxiety questionnaire. Protein carbonyl, total thiol and malondialdehyde (MDA) levels were determined in serum. Participants reported significantly higher levels of subjective anxiety during the exam period than post vacation. Also the level of total thiol was significantly lower during the exam period compared with post vacation (p<0.001). Meanwhile, protein carbonyl and MDA levels during the exams were significantly higher than those in post-exam period (p<0.01). During the exam period, there was a negative correlation between serum total thiol levels and the severity of anxiety (r=-0.45, p<0.01). A significant positive correlation between the changes in serum protein carbonyl and MDA levels, also between those markers and anxiety score was found during the exam period. The high level of protein carbonyl and MDA, also low level of total thiol during the exam period demonstrated an oxidative damage to proteins and lipids in stress conditions. Our results suggest that oxidative damage to cellular compounds may be one of the mechanisms involved in the pathogenesis of anxiety. PMID:23688949

  14. Protein oxidative modifications during electrospray ionization: solution phase electrochemistry or corona discharge-induced radical attack?

    PubMed

    Boys, Brian L; Kuprowski, Mark C; Noël, James J; Konermann, Lars

    2009-05-15

    The exposure of solution-phase proteins to reactive oxygen species (ROS) causes oxidative modifications, giving rise to the formation of covalent +16 Da adducts. Electrospray ionization (ESI) mass spectrometry (MS) is the most widely used method for monitoring the extent of these modifications. Unfortunately, protein oxidation can also take place as an experimental artifact during ESI, such that it may be difficult to assess the actual level of oxidation in bulk solution. Previous work has demonstrated that ESI-induced oxidation is highly prevalent when operating at strongly elevated capillary voltage V(0) (e.g., +8 kV) and with oxygen nebulizer gas in the presence of a clearly visible corona discharge. Protein oxidation under these conditions is commonly attributed to OH radicals generated in the plasma of the discharge. On the other hand, charge balancing oxidation reactions are known to take place at the metal/liquid interface of the emitter. Previous studies have not systematically explored whether such electrochemical processes could be responsible for the formation of oxidative +16 Da adducts instead of (or in combination with) plasma-generated ROS. Using hemoglobin as a model system, this work illustrates the occurrence of extensive protein oxidation even under typical operating conditions (e.g., V(0) = 3.5 kV, N(2) nebulizer gas). Surprisingly, measurements of the current flowing in the ESI circuit demonstrate that a weak corona discharge persists for these relatively gentle settings. On the basis of comparative experiments with nebulizer gases of different dielectric strength, it is concluded that ROS generated under discharge conditions are solely responsible for ESI-induced protein oxidation. This result is corroborated through off-line electrolysis experiments designed to mimic the electrochemical processes taking place during ESI. Our findings highlight the necessity of using easily oxidizable internal standards in biophysical or biomedical ESI

  15. Methionine Oxidation Perturbs the Structural Core of the Prion Protein and Suggests a Generic Misfolding Pathway*

    PubMed Central

    Younan, Nadine D.; Nadal, Rebecca C.; Davies, Paul; Brown, David R.; Viles, John H.

    2012-01-01

    Oxidative stress and misfolding of the prion protein (PrPC) are fundamental to prion diseases. We have therefore probed the effect of oxidation on the structure and stability of PrPC. Urea unfolding studies indicate that H2O2 oxidation reduces the thermodynamic stability of PrPC by as much as 9 kJ/mol. 1H-15N NMR studies indicate methionine oxidation perturbs key hydrophobic residues on one face of helix-C as follows: Met-205, Val-209, and Met-212 together with residues Val-160 and Tyr-156. These hydrophobic residues pack together and form the structured core of the protein, stabilizing its ternary structure. Copper-catalyzed oxidation of PrPC causes a more significant alteration of the structure, generating a monomeric molten globule species that retains its native helical content. Further copper-catalyzed oxidation promotes extended β-strand structures that lack a cooperative fold. This transition from the helical molten globule to β-conformation has striking similarities to a misfolding intermediate generated at low pH. PrP may therefore share a generic misfolding pathway to amyloid fibers, irrespective of the conditions promoting misfolding. Our observations support the hypothesis that oxidation of PrP destabilizes the native fold of PrPC, facilitating the transition to PrPSc. This study gives a structural and thermodynamic explanation for the high levels of oxidized methionine in scrapie isolates. PMID:22654104

  16. Digesting pythons quickly oxidize the proteins in their meals and save the lipids for later.

    PubMed

    McCue, Marshall D; Guzman, R Marena; Passement, Celeste A

    2015-07-01

    Pythons digesting rodent meals exhibit up to 10-fold increases in their resting metabolic rate (RMR); this increase in RMR is termed specific dynamic action (SDA). Studies have shown that SDA is partially fueled by oxidizing dietary nutrients, yet it remains unclear whether the proteins and the lipids in their meals contribute equally to this energy demand. We raised two populations of mice on diets labeled with either [(13)C]leucine or [(13)C]palmitic acid to intrinsically enrich the proteins and lipids in their bodies, respectively. Ball pythons (Python regius) were fed whole mice (and pureed mice 3 weeks later), after which we measured their metabolic rates and the δ(13)C in the breath. The δ(13)C values in the whole bodies of the protein- and lipid-labeled mice were generally similar (i.e. 5.7±4.7‰ and 2.8±5.4‰, respectively) but the oxidative kinetics of these two macronutrient pools were quite different. We found that the snakes oxidized 5% of the protein and only 0.24% of the lipids in their meals within 14 days. Oxidation of the dietary proteins peaked 24 h after ingestion, at which point these proteins provided ∼90% of the metabolic requirement of the snakes, and by 14 days the oxidation of these proteins decreased to nearly zero. The oxidation of the dietary lipids peaked 1 day later, at which point these lipids supplied ∼25% of the energy demand. Fourteen days after ingestion, these lipids were still being oxidized and continued to account for ∼25% of the metabolic rate. Pureeing the mice reduced the cost of gastric digestion and decreased SDA by 24%. Pureeing also reduced the oxidation of dietary proteins by 43%, but it had no effect on the rates of dietary lipid oxidation. Collectively, these results demonstrate that pythons are able to effectively partition the two primary metabolic fuels in their meals. This approach of uniquely labeling the different components of the diet will allow researchers to examine new questions about

  17. Incorporation of electrochemical advanced oxidation processes in a multistage treatment system for sanitary landfill leachate.

    PubMed

    Moreira, Francisca C; Soler, J; Fonseca, Amélia; Saraiva, Isabel; Boaventura, Rui A R; Brillas, Enric; Vilar, Vítor J P

    2015-09-15

    The current study has proved the technical feasibility of including electrochemical advanced oxidation processes (EAOPs) in a multistage strategy for the remediation of a sanitary landfill leachate that embraced: (i) first biological treatment to remove the biodegradable organic fraction, oxidize ammonium and reduce alkalinity, (ii) coagulation of the bio-treated leachate to precipitate humic acids and particles, followed by separation of the clarified effluent, and (iii) oxidation of the resulting effluent by an EAOP to degrade the recalcitrant organic matter and increase its biodegradability so that a second biological process for removal of biodegradable organics and nitrogen content could be applied. The influence of current density on an UVA photoelectro-Fenton (PEF) process was firstly assessed. The oxidation ability of various EAOPs such as electro-Fenton (EF) with two distinct initial total dissolved iron concentrations ([TDI]0), PEF and solar PEF (SPEF) was further evaluated and these processes were compared with their analogous chemical ones. A detailed assessment of the two first treatment stages was made and the biodegradability enhancement during the SPEF process was determined by a Zahn-Wellens test to define the ideal organics oxidation state to stop the EAOP and apply the second biological treatment. The best current density was 200 mA cm(-2) for a PEF process using a BDD anode, [TDI]0 of 60 mg L(-1), pH 2.8 and 20 °C. The relative oxidation ability of EAOPs increased in the order EF with 12 mg [TDI]0 L(-1) < EF with 60 mg [TDI]0 L(-1) < PEF with 60 mg [TDI]0 L(-1) ≤ SPEF with 60 mg [TDI]0 L(-1), using the abovementioned conditions. While EF process was much superior to the Fenton one, the superiority of PEF over photo-Fenton was less evident and SPEF attained similar degradation to solar photo-Fenton. To provide a final dissolved organic carbon (DOC) of 163 mg L(-1) to fulfill the discharge limits into the environment after

  18. The myeloperoxidase-derived oxidant hypothiocyanous acid inhibits protein tyrosine phosphatases via oxidation of key cysteine residues.

    PubMed

    Cook, Naomi L; Moeke, Cassidy H; Fantoni, Luca I; Pattison, David I; Davies, Michael J

    2016-01-01

    Phosphorylation of protein tyrosine residues is critical to cellular processes, and is regulated by kinases and phosphatases (PTPs). PTPs contain a redox-sensitive active site Cys residue, which is readily oxidized. Myeloperoxidase, released from activated leukocytes, catalyzes thiocyanate ion (SCN(-)) oxidation by H2O2 to form hypothiocyanous acid (HOSCN), an oxidant that targets Cys residues. Dysregulated phosphorylation and elevated MPO levels have been associated with chronic inflammatory diseases where HOSCN can be generated. Previous studies have shown that HOSCN inhibits isolated PTP1B and induces cellular dysfunction in cultured macrophage-like cells. The present study extends this previous work and shows that physiologically-relevant concentrations of HOSCN alter the activity and structure of other members of the wider PTP family (including leukocyte antigen-related PTP, PTP-LAR; T-cell PTP, TC-PTP; CD45 and Src homology phosphatase-1, Shp-1) by targeting Cys residues. Isolated PTP activity, and activity in lysates of human monocyte-derived macrophages (HMDM) was inhibited by 0-100 µM HOSCN with this being accompanied by reversible oxidation of Cys residues, formation of sulfenic acids or sulfenyl-thiocyanates (detected by Western blotting, and LC-MS as dimedone adducts), and structural changes. LC-MS/MS peptide mass-mapping has provided data on the modified Cys residues in PTP-LAR. This study indicates that inflammation-induced oxidants, and particularly myeloperoxidase-derived species, can modulate the activity of multiple members of the PTP superfamily via oxidation of Cys residues to sulfenic acids. This alteration of the balance of PTP/kinase activity may perturb protein phosphorylation and disrupt cell signaling with subsequent induction of apoptosis at sites of inflammation. PMID:26616646

  19. Amorphous mixed-metal hydroxide nanostructures for advanced water oxidation catalysts

    NASA Astrophysics Data System (ADS)

    Gao, Y. Q.; Liu, X. Y.; Yang, G. W.

    2016-02-01

    The design of highly efficient, durable, and earth-abundant catalysts for the oxygen evolution reaction (OER) is crucial in order to promote energy conversion and storage processes. Here, we synthesize amorphous mixed-metal (Ni-Fe) hydroxide nanostructures with a homogeneous distribution of Ni/Fe as well as a tunable Ni/Fe ratio by a simple, facile, green and low-cost electrochemical technique, and we demonstrate that the synthesized amorphous nanomaterials possess ultrahigh activity and super long-term cycle stability in the OER process. The amorphous Ni0.71Fe0.29(OH)x nanostructure affords a current density of 10 mA cm-2 at an overpotential of a mere 0.296 V and a small Tafel slope of 58 mV dec-1, while no deactivation is detected in the CV testing even up to 30 000 cycles, which suggests the promising application of these amorphous nanomaterials in electrochemical oxidation. Meanwhile, the distinct catalytic activities among these amorphous Ni-Fe hydroxide nanostructures prompts us to take notice of the composition of the alloy hydroxides/oxides when studying their catalytic properties, which opens an avenue for the rational design and controllable preparation of such amorphous nanomaterials as advanced OER electrocatalysts.The design of highly efficient, durable, and earth-abundant catalysts for the oxygen evolution reaction (OER) is crucial in order to promote energy conversion and storage processes. Here, we synthesize amorphous mixed-metal (Ni-Fe) hydroxide nanostructures with a homogeneous distribution of Ni/Fe as well as a tunable Ni/Fe ratio by a simple, facile, green and low-cost electrochemical technique, and we demonstrate that the synthesized amorphous nanomaterials possess ultrahigh activity and super long-term cycle stability in the OER process. The amorphous Ni0.71Fe0.29(OH)x nanostructure affords a current density of 10 mA cm-2 at an overpotential of a mere 0.296 V and a small Tafel slope of 58 mV dec-1, while no deactivation is detected in the CV

  20. Flavone inhibits nitric oxide synthase (NOS) activity, nitric oxide production and protein S-nitrosylation in breast cancer cells

    SciTech Connect

    Zhu, Wenzhen; Yang, Bingwu; Fu, Huiling; Ma, Long; Liu, Tingting; Chai, Rongfei; Zheng, Zhaodi; Zhang, Qunye; Li, Guorong

    2015-03-13

    As the core structure of flavonoids, flavone has been proved to possess anticancer effects. Flavone's growth inhibitory functions are related to NO. NO is synthesized by nitric oxide synthase (NOS), and generally increased in a variety of cancer cells. NO regulates multiple cellular responses by S-nitrosylation. In this study, we explored flavone-induced regulations on nitric oxide (NO)-related cellular processes in breast cancer cells. Our results showed that, flavone suppresses breast cancer cell proliferation and induces apoptosis. Flavone restrains NO synthesis by does-dependent inhibiting NOS enzymatic activity. The decrease of NO generation was detected by fluorescence microscopy and flow cytometry. Flavone-induced inhibitory effect on NOS activity is dependent on intact cell structure. For the NO-induced protein modification, flavone treatment significantly down-regulated protein S-nitrosylation, which was detected by “Biotin-switch” method. The present study provides a novel, NO-related mechanism for the anticancer function of flavone. - Highlights: • Flavone inhibits proliferation and induces apoptosis in MCF-7 cells. • Flavone decreases nitric oxide production by inhibiting NOS enzymatic activity in breast cancer cells. • Flavone down-regulates protein S-nitrosylation.

  1. Redox Proteomics in Human Biofluids: Sample Preparation, Separation and Immunochemical Tagging for Analysis of Protein Oxidation.

    PubMed

    Di Domenico, Fabio; Perluigi, Marzia; Butterfield, D Allan

    2016-01-01

    Proteomics offers the simultaneous detection of a large number of proteins in a single experiment and can provide important information regarding crucial aspects of specific proteins, particularly post-translational modifications (PTMs). Investigations of oxidative PTMs are currently performed using focused redox proteomics techniques, which rely on gel electrophoresis separations of intact proteins with the final detection of oxidative PTMs being performed by mass spectrometry (MS) analysis. The application of this technique to human biofluids is being subject of increasing investigation and is expected to provide new insights on the oxidative status of the peripheral proteome in neurological diseases such as Alzheimer's disease, towards purposes of early diagnosis and prognosis. This chapter describes all the experimental steps to perform redox proteomics analysis of cerebrospinal fluid and plasma/serum samples. PMID:26235080

  2. Oxidized-LDL induce the expression of heat shock protein 70 in human endothelial cells.

    PubMed

    Zhu, W; Roma, P; Pellegatta, F; Catapano, A L

    1994-04-15

    Heat shock proteins are detectable in human atherosclerotic plaques, especially in endothelial cells. In this report we show by immunofluorescence that incubation "in vitro" with OxLDL is a stress capable of inducing the expression of heat shock protein 70 in both the EAhy-926 cell line and human umbilical vein endothelial cells (HUVEC). This induction was parallel to the cytotoxicity of oxidized LDL as determined by [3H]adenine release. When cells were confluent, however, both effects were greatly reduced. We speculate that induction of hsp70 is related to the cytotoxicity of oxidized LDL and that the detection of heat shock proteins in human atherosclerotic plaques is a further indication for the presence "in vivo" of oxidized LDL. These observations may be relevant to the understanding of endothelial response to injury in proatherosclerotic events. PMID:8166710

  3. Simultaneous nitrate reduction and acetaminophen oxidation using the continuous-flow chemical-less VUV process as an integrated advanced oxidation and reduction process.

    PubMed

    Moussavi, Gholamreza; Shekoohiyan, Sakine

    2016-11-15

    This work was aimed at investigating the performance of the continuous-flow VUV photoreactor as a novel chemical-less advanced process for simultaneously oxidizing acetaminophen (ACT) as a model of pharmaceuticals and reducing nitrate in a single reactor. Solution pH was an important parameter affecting the performance of VUV; the highest ACT oxidation and nitrate reduction attained at solution pH between 6 and 8. The ACT was oxidized mainly by HO while the aqueous electrons were the main working agents in the reduction of nitrate. The performance of VUV photoreactor improved with the increase of hydraulic retention time (HRT); the complete degradation of ACT and ∼99% reduction of nitrate with 100% N2 selectivity achieved at HRT of 80min. The VUV effluent concentrations of nitrite and ammonium at HRT of 80min were below the drinking water standards. The real water sample contaminated with the ACT and nitrate was efficiently treated in the VUV photoreactor. Therefore, the VUV photoreactor is a chemical-less advanced process in which both advanced oxidation and advanced reduction reactions are accomplished. This unique feature possesses VUV photoreactor as a promising method of treating water contaminated with both pharmaceutical and nitrate. PMID:27434736

  4. Advanced treatment of biologically pretreated coal gasification wastewater by a novel integration of catalytic ultrasound oxidation and membrane bioreactor.

    PubMed

    Jia, Shengyong; Han, Hongjun; Zhuang, Haifeng; Xu, Peng; Hou, Baolin

    2015-01-01

    Laboratorial scale experiments were conducted to investigate a novel system integrating catalytic ultrasound oxidation (CUO) with membrane bioreactor (CUO-MBR) on advanced treatment of biologically pretreated coal gasification wastewater. Results indicated that CUO with catalyst of FeOx/SBAC (sewage sludge based activated carbon (SBAC) which loaded Fe oxides) represented high efficiencies in eliminating TOC as well as improving the biodegradability. The integrated CUO-MBR system with low energy intensity and high frequency was more effective in eliminating COD, BOD5, TOC and reducing transmembrane pressure than either conventional MBR or ultrasound oxidation integrated MBR. The enhanced hydroxyl radical oxidation, facilitation of substrate diffusion and improvement of cell enzyme secretion were the mechanisms for CUO-MBR performance. Therefore, the integrated CUO-MBR was the promising technology for advanced treatment in engineering applications. PMID:25936898

  5. Myeloperoxidase-derived oxidants selectively disrupt the protein core of the heparan sulfate proteoglycan perlecan

    PubMed Central

    Rees, Martin D.; Whitelock, John M.; Malle, Ernst; Chuang, Christine Y.; Iozzo, Renato V.; Nilasaroya, Anastasia; Davies, Michael J.

    2009-01-01

    The potent oxidants hypochlorous acid (HOCl) and hypobromous acid (HOBr) are produced extracellularly by myeloperoxidase, following release of this enzyme from activated leukocytes. The subendothelial extracellular matrix is a key site for deposition of myeloperoxidase and damage by myeloperoxidase-derived oxidants, with this damage implicated in the impairment of vascular cell function during acute inflammatory responses and chronic inflammatory diseases such as atherosclerosis. The heparan sulfate proteoglycan perlecan, a key component of the subendothelial extracellular matrix, regulates important cellular processes and is a potential target for HOCl and HOBr. It is shown here that perlecan binds myeloperoxidase via its heparan sulfate side chains and that this enhances oxidative damage by myeloperoxidase-derived HOCl and HOBr. This damage involved selective degradation of the perlecan protein core without detectable alteration of its heparan sulfate side chains, despite the presence of reactive GlcNH2 resides within this glycosaminoglycan. Modification of the protein core by HOCl and HOBr (measured by loss of immunological recognition of native protein epitopes and the appearance of oxidatively-modified protein epitopes) was associated with an impairment of its ability to support endothelial cell adhesion, with this observed at a pathologically-achievable oxidant dose of 425 nmol oxidant/mg protein. In contrast, the heparan sulfate chains of HOCl/HOBr-modified perlecan retained their ability to bind FGF-2 and collagen V and were able to promote FGF-2-dependent cellular proliferation. Collectively, these data highlight the potential role of perlecan oxidation, and consequent deregulation of cell function, in vascular injuries by myeloperoxidase-derived HOCl and HOBr. PMID:19788922

  6. Purification and Characterization of the Manganese(II) Oxidizing Protein from Erythrobacter sp. SD-21

    NASA Astrophysics Data System (ADS)

    Nakama, K. R.; Lien, A.; Johnson, H. A.

    2013-12-01

    The manganese(II) oxidizing protein (Mop) found in the alpha-proteobacterium Erythrobacter sp. SD-21 catalyzes the formation of insoluble Mn(III/IV) oxides from soluble Mn(II). These Mn(III/IV) oxides formed are one of the strongest naturally occurring oxides, next to oxygen, and can be used to adsorb and oxidize toxic chemicals from the surrounding environment. Because of the beneficial use in the treatment of contaminated sources, the mechanism and biochemical properties of this novel enzyme are being studied. Due to low expression levels in the native host strain, purification of Mop has been problematic. To overcome this problem the gene encoding Mop, mopA, was cloned from the native host into a C-terminal histidine tag vector and expressed in Escherichia coli cells. Affinity chromatography under denaturing conditions have been applied in attempts to purify an active Mop. Western blots have confirmed that the protein is being expressed and is at the expected size of 250 kDa. Preliminary characterization on crude extract containing Mop has shown a Km and vmax value of 2453 uM and 0.025 uM min-1, respectively. Heme and pyrroloquinoline quinone can stimulate Mn(II) oxidizing activity, but hydrogen peroxide does not affect activity, despite the sequence similarity to animal heme peroxidase proteins. Research has been shown that calcium is essential for Mop activity. Purifying an active Mn(II) oxidizing protein will allow for a better understanding behind the enigmatic process of Mn(II) oxidation.

  7. Detection and quantification of protein oxidation in sarcopenic models: a mass spectrometry study.

    PubMed

    Pasha, Sabah; Tveen Jensen, Karina; Pitt, Andrew R; Spickett, Corinne M

    2014-10-01

    Oxidised biomolecules in aged tissue could potentially be used as biomarkers for age-related diseases; however, it is still unclear whether they causatively contribute to ageing or are consequences of the ageing process. To assess the potential of using protein oxidation as markers of ageing, mass spectrometry (MS) was employed for the identification and quantification of oxidative modifications in obese (ob/ob) mice. Lean muscle mass and strength is reduced in obesity, representing a sarcopenic model in which the levels of oxidation can be evaluated for different muscular systems including calcium homeostasis, metabolism and contractility. Several oxidised residues were identified by tandem MS (MS/MS) in both muscle homogenate and isolated sarcoplasmic reticulum (SR), an organelle that regulates intracellular calcium levels in muscle. These modifications include oxidation of methionine, cysteine, tyrosine, and tryptophan in several proteins such as sarcoplasmic reticulum calcium ATPase (SERCA), glycogen phosphorylase, and myosin. Once modifications had been identified, multiple reaction monitoring MS (MRM) was used to quantify the percentage modification of oxidised residues within the samples. Preliminary data suggests proteins in ob/ob mice are more oxidised than the controls. For example SERCA, which constitutes 60-70% of the SR, had approximately a 2-fold increase in cysteine trioxidation of Cys561 in the obese model when compared to the control. Other obese muscle proteins have also shown a similar increase in oxidation for various residues. Further analysis with complex protein mixtures will determine the potential diagnostic use of MRM experiments for analysing protein oxidation in small biological samples such as muscle needle biopsies. PMID:26461380

  8. Medium pressure UV combined with chlorine advanced oxidation for trichloroethylene destruction in a model water.

    PubMed

    Wang, Ding; Bolton, James R; Hofmann, Ron

    2012-10-01

    The effectiveness of ultraviolet (UV) combined with chlorine as a novel advanced oxidation process (AOP) for drinking water treatment was evaluated in a bench scale study by comparing the rate of trichloroethylene (TCE) decay when using UV/chlorine to the rates of decay by UV alone and UV/hydrogen peroxide (H₂O₂) at various pH values. A medium pressure mercury UV lamp was used. The UV/chlorine process was more efficient than the UV/H₂O₂ process at pH 5, but in the neutral and alkaline pH range, the UV/H₂O₂ process became more efficient. The pH effect was probably controlled by the increasing concentration of OCl⁻ at higher pH values. A mechanistic kinetic model of the UV/chlorine treatment of TCE showed good agreement with the experimental data. PMID:22763292

  9. Removal of persistent organic pollutant hexachlorocyclohexane isomers by advanced oxidation process.

    PubMed

    2012-04-01

    Organochlorine insecticide Lindane (gamma-Hexachlorocyclohexane) and its isomers (alpha, beta, delta-HCH) are recalcitrant and toxic compounds. They were progressively banished in most of the countries, because of their persistence and toxicity. Due to their nonselective production process and widespread use, they are still occurring in the environment. These insecticides and isomers were detected in all media like soil, ground water, sediments, vegetables and even in human tissues. In this study, UV, H2O2, UV+H2O2, Fenton's reagent, UV+Fenton's reagent, Advanced Oxidation Process (AOP) have been applied for degradation of HCH isomers (a, beta, gamma and delta-HCH). The results revealed that the UV+H2O2 treatment was most effective, which could do 99% degradation of all isomers of HCH within 75 minutes. The results in detail are presented and discussed in this paper. PMID:24749381

  10. Advanced oxidation processes for wastewater treatment using a plasma/ozone combination system

    NASA Astrophysics Data System (ADS)

    Takeuchi, Nozomi; Kamiya, Yu; Saeki, Ryo; Tachibana, Kosuke; Yasuoka, Koichi

    2014-10-01

    Advanced oxidation process (AOP) using OH radicals is a promising method for the decomposition of persistent organic compounds in wastewater. Although many types of plasma reactors have been developed for the AOP, they are unsuitable for the complete decomposition of highly concentrated organic compounds. The reason for the incomplete decomposition is that OH radicals, particularly at a high density, recombine among themselves to form hydrogen peroxide. We have developed a combination plasma reactor in which ozone gas is fed, so that the generated hydrogen peroxide is re-converted to OH radicals. Pulsed plasmas generated within oxygen bubbles supply not only OH radicals but also hydrogen peroxide into wastewater. The total organic carbon (TOC) of the wastewater was more than 1 gTOC/L. The TOC values decreased linearly with time, and the persistent compounds which could not be decomposed by ozone were completely mineralized within 8 h of operation.

  11. Intrinsic Chemiluminescence Generation during Advanced Oxidation of Persistent Halogenated Aromatic Carcinogens.

    PubMed

    Mao, Li; Liu, Yu-Xiang; Huang, Chun-Hua; Gao, Hui-Ying; Kalyanaraman, Balaraman; Zhu, Ben-Zhan

    2015-07-01

    The ubiquitous distribution coupled with their carcinogenicity has raised public concerns on the potential risks to both human health and the ecosystem posed by the halogenated aromatic compounds (XAr). Recently, advanced oxidation processes (AOPs) have been increasingly favored as an "environmentally-green" technology for the remediation of such recalcitrant and highly toxic XAr. Here, we show that AOPs-mediated degradation of the priority pollutant pentachlorophenol and all other XAr produces an intrinsic chemiluminescence that directly depends on the generation of the extremely reactive hydroxyl radicals. We propose that the hydroxyl radical-dependent formation of quinoid intermediates and electronically excited carbonyl species is responsible for this unusual chemiluminescence production. A rapid, sensitive, simple, and effective chemiluminescence method was developed to quantify trace amounts of XAr and monitor their real-time degradation kinetics. These findings may have broad biological and environmental implications for future research on this important class of halogenated persistent organic pollutants. PMID:26009932

  12. Protein-RNA cross-linking in the ribosomes of yeast under oxidative stress.

    PubMed

    Mirzaei, Hamid; Regnier, Fred

    2006-12-01

    Living systems have efficient degradative pathways for dealing with the fact that reactive oxygen species (ROS) derived from cellular metabolism and the environment oxidatively damage proteins and DNA. But aggregation and cross-linking can occur as well, leading to a series of problems including disruption of cellular regulation, mutations, and even cell death. The mechanism(s) by which protein aggregation occurs and the macromolecular species involved are poorly understood. In the study reported here, evidence is provided for a new type of aggregate between proteins and RNA in ribosomes. While studying the effect of oxidative stress induced in the yeast proteome it was noted that ribosomal proteins were widely oxidized. Eighty six percent of the proteins in yeast ribosomes were found to be carbonylated after stressing yeast cell cultures with hydrogen peroxide. Moreover, many of these proteins appeared to be cross-linked based on their coelution patterns during RPC separation. Since they were not in direct contact, it was not clear how this could occur unless it was through the RNA separating them in the ribosome. This was confirmed in a multiple-step process, the first being derivatization of all carbonylated proteins in cell lysates with biotin hydrazide through Schiff base formation. Following reduction of Schiff bases with sodium cyanoborohydride, biotinylated proteins were selected from cell lysates with avidin affinity chromatography. Oxidized proteins thus captured were then selected again using boronate affinity chromatography to capture vicinal diol-containing proteins. This would include proteins cross-linked to an RNA fragment containing a ribose residue with 2',3'-hydroxyl groups. Some glycoproteins would also be selected by this process. LC/MS/MS analyses of tryptic peptides derived from proteins captured by this process along with MASCOT searches resulted in the identification of 37 ribosomal proteins that appear to be cross-linked to RNA

  13. A Review of the Latest Advances in Encrypted Bioactive Peptides from Protein-Rich Waste

    PubMed Central

    Lemes, Ailton Cesar; Sala, Luisa; Ores, Joana da Costa; Braga, Anna Rafaela Cavalcante; Egea, Mariana Buranelo; Fernandes, Kátia Flávia

    2016-01-01

    Bioactive peptides are considered the new generation of biologically active regulators that not only prevent the mechanism of oxidation and microbial degradation in foods but also enhanced the treatment of various diseases and disorders, thus increasing quality of life. This review article emphasizes recent advances in bioactive peptide technology, such as: (i) new strategies for transforming bioactive peptides from residual waste into added-value products; (ii) nanotechnology for the encapsulation, protection and release of controlled peptides; and (iii) use of techniques of large-scale recovery and purification of peptides aiming at future applications to pharmaceutical and food industries. PMID:27322241

  14. A Review of the Latest Advances in Encrypted Bioactive Peptides from Protein-Rich Waste.

    PubMed

    Lemes, Ailton Cesar; Sala, Luisa; Ores, Joana da Costa; Braga, Anna Rafaela Cavalcante; Egea, Mariana Buranelo; Fernandes, Kátia Flávia

    2016-01-01

    Bioactive peptides are considered the new generation of biologically active regulators that not only prevent the mechanism of oxidation and microbial degradation in foods but also enhanced the treatment of various diseases and disorders, thus increasing quality of life. This review article emphasizes recent advances in bioactive peptide technology, such as: (i) new strategies for transforming bioactive peptides from residual waste into added-value products; (ii) nanotechnology for the encapsulation, protection and release of controlled peptides; and (iii) use of techniques of large-scale recovery and purification of peptides aiming at future applications to pharmaceutical and food industries. PMID:27322241

  15. Advances and New Concepts in Alcohol-Induced Organelle Stress, Unfolded Protein Responses and Organ Damage

    PubMed Central

    Ji, Cheng

    2015-01-01

    Alcohol is a simple and consumable biomolecule yet its excessive consumption disturbs numerous biological pathways damaging nearly all organs of the human body. One of the essential biological processes affected by the harmful effects of alcohol is proteostasis, which regulates the balance between biogenesis and turnover of proteins within and outside the cell. A significant amount of published evidence indicates that alcohol and its metabolites directly or indirectly interfere with protein homeostasis in the endoplasmic reticulum (ER) causing an accumulation of unfolded or misfolded proteins, which triggers the unfolded protein response (UPR) leading to either restoration of homeostasis or cell death, inflammation and other pathologies under severe and chronic alcohol conditions. The UPR senses the abnormal protein accumulation and activates transcription factors that regulate nuclear transcription of genes related to ER function. Similarly, this kind of protein stress response can occur in other cellular organelles, which is an evolving field of interest. Here, I review recent advances in the alcohol-induced ER stress response as well as discuss new concepts on alcohol-induced mitochondrial, Golgi and lysosomal stress responses and injuries. PMID:26047032

  16. Cellular accumulation of Cys326-OGG1 protein complexes under conditions of oxidative stress

    PubMed Central

    Kaur, M.P.; Guggenheim, E.J.; Pulisciano, C.; Akbar, S.; Kershaw, R.M.; Hodges, N.J.

    2014-01-01

    The common Ser326Cys polymorphism in the base excision repair protein 8-oxoguanine glycosylase 1 is associated with a reduced capacity to repair oxidative DNA damage particularly under conditions of intracellular oxidative stress and there is evidence that Cys326-OGG1 homozygous individuals have increased susceptibility to specific cancer types. Indirect biochemical studies have shown that reduced repair capacity is related to OGG1 redox modification and also possibly OGG1 dimer formation. In the current study we have used bimolecular fluorescence complementation to study for the first time a component of the base excision repair pathway and applied it to visualise accumulation of Cys326-OGG1 protein complexes in the native cellular environment. Fluorescence was observed both within and around the cell nucleus, was shown to be specific to cells expressing Cys326-OGG1 and only occurred in cells under conditions of cellular oxidative stress following depletion of intracellular glutathione levels by treatment with buthionine sulphoximine. Furthermore, OGG1 complex formation was inhibited by incubation of cells with the thiol reducing agents β-mercaptoethanol and dithiothreitol and the antioxidant dimethylsulfoxide indicating a causative role for oxidative stress in the formation of OGG1 cellular complexes. In conclusion, this study has provided for the first time evidence of redox sensitive Cys326-OGG1 protein accumulation in cells under conditions of intracellular oxidative stress that may be related to the previously reported reduced repair capacity of Cys326-OGG1 specifically under conditions of oxidative stress. PMID:24680828

  17. Serum protein layers on parylene-C and silicon oxide: Effect on cell adhesion

    PubMed Central

    Delivopoulos, Evangelos; Ouberai, Myriam M.; Coffey, Paul D.; Swann, Marcus J.; Shakesheff, Kevin M.; Welland, Mark E.

    2015-01-01

    Among the range of materials used in bioengineering, parylene-C has been used in combination with silicon oxide and in presence of the serum proteins, in cell patterning. However, the structural properties of adsorbed serum proteins on these substrates still remain elusive. In this study, we use an optical biosensing technique to decipher the properties of fibronectin (Fn) and serum albumin adsorbed on parylene-C and silicon oxide substrates. Our results show the formation of layers with distinct structural and adhesive properties. Thin, dense layers are formed on parylene-C, whereas thicker, more diffuse layers are formed on silicon oxide. These results suggest that Fn acquires a compact structure on parylene-C and a more extended structure on silicon oxide. Nonetheless, parylene-C and silicon oxide substrates coated with Fn host cell populations that exhibit focal adhesion complexes and good cell attachment. Albumin adopts a deformed structure on parylene-C and a globular structure on silicon oxide, and does not support significant cell attachment on either surface. Interestingly, the co-incubation of Fn and albumin at the ratio found in serum, results in the preferential adsorption of albumin on parylene-C and Fn on silicon oxide. This finding is supported by the exclusive formation of focal adhesion complexes in differentiated mouse embryonic stem cells (CGR8), cultured on Fn/albumin coated silicon oxide, but not on parylene-C. The detailed information provided in this study on the distinct properties of layers of serum proteins on substrates such as parylene-C and silicon oxide is highly significant in developing methods for cell patterning. PMID:25555155

  18. Nuclear Cytoplasmic Trafficking of Proteins is a Major Response of Human Fibroblasts to Oxidative Stress

    PubMed Central

    Baqader, Noor O.; Radulovic, Marko; Crawford, Mark; Stoeber, Kai; Godovac-Zimmermann, Jasminka

    2014-01-01

    We have used a subcellular spatial razor approach based on LC–MS/MS-based proteomics with SILAC isotope labeling to determine changes in protein abundances in the nuclear and cytoplasmic compartments of human IMR90 fibroblasts subjected to mild oxidative stress. We show that response to mild tert-butyl hydrogen peroxide treatment includes redistribution between the nucleus and cytoplasm of numerous proteins not previously associated with oxidative stress. The 121 proteins with the most significant changes encompass proteins with known functions in a wide variety of subcellular locations and of cellular functional processes (transcription, signal transduction, autophagy, iron metabolism, TCA cycle, ATP synthesis) and are consistent with functional networks that are spatially dispersed across the cell. Both nuclear respiratory factor 2 and the proline regulatory axis appear to contribute to the cellular metabolic response. Proteins involved in iron metabolism or with iron/heme as a cofactor as well as mitochondrial proteins are prominent in the response. Evidence suggesting that nuclear import/export and vesicle-mediated protein transport contribute to the cellular response was obtained. We suggest that measurements of global changes in total cellular protein abundances need to be complemented with measurements of the dynamic subcellular spatial redistribution of proteins to obtain comprehensive pictures of cellular function. PMID:25133973

  19. Can activated sludge treatments and advanced oxidation processes remove organophosphorus flame retardants?

    PubMed

    Cristale, Joyce; Ramos, Dayana D; Dantas, Renato F; Machulek Junior, Amilcar; Lacorte, Silvia; Sans, Carme; Esplugas, Santiago

    2016-01-01

    This study aims to determine the occurrence of 10 OPFRs (including chlorinated, nonchlorinated alkyl and aryl compounds) in influent, effluent wastewaters and partitioning into sludge of 5 wastewater treatment plants (WWTP) in Catalonia (Spain). All target OPFRs were detected in the WWTPs influents, and the total concentration ranged from 3.67 µg L(-1) to 150 µg L(-1). During activated sludge treatment, most OPFRs were accumulated in the sludge at concentrations from 35.3 to 9980 ng g(-1) dw. Chlorinated compounds tris(2-chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCIPP) and tris(2,3-dichloropropyl) phosphate (TDCPP) were not removed by the conventional activated sludge treatment and they were released by the effluents at approximately the same inlet concentration. On the contrary, aryl compounds tris(methylphenyl) phosphate (TMPP) and 2-ethylhexyl diphenyl phosphate (EHDP) together with alkyl tris(2-ethylhexyl) phosphate (TEHP) were not detected in any of the effluents. Advanced oxidation processes (UV/H2O2 and O3) were applied to investigate the degradability of recalcitrant OPFRs in WWTP effluents. Those detected in the effluent sample (TCEP, TCIPP, TDCPP, tributyl phosphate (TNBP), tri-iso-butyl phosphate (TIBP) and tris(2-butoxyethyl) phosphate (TBOEP)) had very low direct UV-C photolysis rates. TBOEP, TNBP and TIBP were degraded by UV/H2O2 and O3. Chlorinated compounds TCEP, TDCPP and TCIPP were the most recalcitrant OPFR to the advanced oxidation processes applied. The study provides information on the partitioning and degradability pathways of OPFR within conventional activated sludge WWTPs. PMID:26540311

  20. Two-component magnetic structure of iron oxide nanoparticles mineralized in Listeria innocua protein cages

    NASA Astrophysics Data System (ADS)

    Usselman, Robert J.; Klem, Michael T.; Russek, Stephen E.; Young, Mark; Douglas, Trevor; Goldfarb, Ron B.

    2010-06-01

    Magnetometry was used to determine the magnetic properties of maghemite (γ-Fe2O3) nanoparticles formed within Listeria innocua protein cage. The electron magnetic resonance spectrum shows the presence of at least two magnetization components. The magnetization curves are explained by a sum of two Langevin functions in which each filled protein cage contains both a large magnetic iron oxide core plus an amorphous surface consisting of small noncoupled iron oxide spin clusters. This model qualitatively explains the observed decrease in the temperature dependent saturation moment and removes an unrealistic temperature dependent increase in the particle moment often observed in nanoparticle magnetization measurements.

  1. The derivatization of oxidized polysaccharides for protein immobilization and affinity chromatography.

    PubMed

    Junowicz, E; Charm, S E

    1976-03-25

    The present report describes the preparation of modified polysaccharides matrices useful for the synthesis of affinity adsorbents and immobilized proteins. Hydrazido-matrices were synthesized by condensing an excess of the bifunctional reagent, adipic acid dihydrazide, with periodate oxidized cellulose paper, Sephadex, or Sepharose matrices. Ribonucleotide dialdehyde cofactors, glyceraldehyde 3-phosphate, pyridoxal 5'-phosphate and oxidized DNAase B were separately bound to the hydrazido-polymers. Azido-matrices obtained by modification of the hydrazido-derivatives were coupled to specific amino ligands such as amino acids and proteins. Several adsorbents were prepared and used as models for affinity chromatography. PMID:1260016

  2. Dicarbonyls linked to damage in the powerhouse: glycation of mitochondrial proteins and oxidative stress

    PubMed Central

    Rabbani, Naila; Thornalley, Paul J.

    2009-01-01

    Protection of mitochondrial proteins from glycation by endogenous dicarbonyl compounds, methylglyoxal and glyoxal, was found recently to prevent increased formation of reactive oxygen species and oxidative and nitrosative damage to the proteome during aging and produce life extension in the nematode Caenorhabditis elegans. This suggests that dicarbonyl glycation damage to the mitochondrial proteome may be a preceding event to mitochondrial dysfunction leading to oxidative stress. Future research will address the functional charges in mitochondrial proteins that are the targets for dicarbonyl glycation. PMID:18793186

  3. Effects of oxidative modification on gel properties of isolated porcine myofibrillar protein by peroxyl radicals.

    PubMed

    Zhou, Feibai; Zhao, Mouming; Zhao, Haifeng; Sun, Weizheng; Cui, Chun

    2014-04-01

    AAPH-derived (2,2'-azobis (2-amidinopropane) dihydrochloride) peroxyl radicals were selected as representative free radicals of lipid peroxidation to investigate the effects of oxidative modifications on isolated porcine myofibrillar protein structures as well as their rheological and gelling properties. Incubation of myofibrillar protein with increasing concentrations of AAPH resulted in a gradual increase (p<0.05) in carbonyl content and SH→S-S conversion. Results from SDS-PAGE indicated that medium (~1 mM) and relatively high (>3 mM) concentrations of AAPH induced aggregation of myosin and denaturation of myosin, troponin and tropomyosin, respectively. These structural changes resulted in changes on gelation of myofibrillar protein. Low level protein oxidation (AAPH≤0.5 mM) had no remarkable effect (p>0.05) on the viscoelastic pattern of myofibrillar protein gelation. Moderate oxidative modification (AAPH~1mM) enhanced the water-holding capacity (WHC) and texture properties of gels, while further oxidation (AAPH>3mM) significantly reduced the gel quality. PMID:24406430

  4. Effect of oxidization and chitosan on the surface activity of soy protein isolate.

    PubMed

    Wang, Wei; Li, Junsheng; Yan, Liujuan; Huang, Guoxia; Dong, Zhen

    2016-10-20

    The objective of this research was to study the effect of oxidization of performic acid and chitosan on the structure and surface properties of soy protein isolate. As the degree of oxidization increased, the emulsifying capacity and stability of all the oxidized soy protein isolate and chitosan (SPI/CHI) systems increased substantially, which were 29.7%, 31.7%, 34.1%, 31.9% and 31.9% respectively compared. Fluorescent spectrum showed that the fluorescence intensity of SPI/CHI conjugates decreased and the higher the oxidized degree was, the lower the fluorescence intensity. Results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that the location of acidic bands of SPI/CHI conjugates moved upwards and broadened. Meanwhile, the basic bands lightened or even disappeared gradually as the oxidization increased. Scanning electron microscope (SEM) showed that the particles became lager as the degree of oxidization increased. Better thermostability of the oxidized SPI/CHI systems was shown in the differential scanning calorimetry (DSC). PMID:27474616

  5. Decolorization of kraft bleaching effluent by advanced oxidation processes using copper (II) as electron acceptor.

    PubMed

    Yeber, María C; Oñate, Katherine P; Vidal, Gladys

    2007-04-01

    Two advanced oxidation processes (AOPs), TiO2/UV/O2 and TiO2/UV/Cu (II), were used to remove color from a Kraft bleaching effluent. The optimal decoloration rate was determined by multivariate analysis, obtaining a mathematical model to evaluate the effect among variables. TiO2 and Cu (II) concentrations and the reaction times were optimized. The experimental design resulted in a quadratic matrix of 30 experiments. Additionally, the pH influence on the color removal was determined by multivariate analysis. Results indicate that color removal was 94% at acidic pH (3.0) in the presence of Cu (11) as an electron acceptor. Under this condition, the biodegradation of the effluent increased from 0.3 to 0.6. Moreover, 70% of COD (chemical oxygen demand) was removed, and the ecotoxicity, measured by Daphnia magna, was reduced. Photocatalytic oxidation to remove the color contained in the Kraft mill bleaching effluent was effective under the following conditions: short reaction time, acidic pH values, and without the addition of oxygen due to the presence of Cu (II) in the effluent. Moreover, residual Cu (II) was a minimum (0.05.mg L(-1)) and was not toxic to the next biological stage. The experimental design methodology indicated that a quadratic polynomial model may be used to representthe efficiencyfor degradation of the Kraft bleach pulp effluent by a photocatalytic process. PMID:17438808

  6. Feasibility studies: UV/chlorine advanced oxidation treatment for the removal of emerging contaminants.

    PubMed

    Sichel, C; Garcia, C; Andre, K

    2011-12-01

    UV/chlorine (UV/HOCl and UV/ClO(2)) Advanced Oxidation Processes (AOPs) were assessed with varying process layout and compared to the state of the art UV/H(2)O(2) AOP. The process comparison focused on the economical and energy saving potential of the UV/chlorine AOP. Therefore the experiments were performed at technical scale (250 L/h continuous flow reactor) and at process energies, oxidant and model contaminant concentrations expected in full scale reference plants. As model compounds the emerging contaminants (ECs): desethylatrazine, sulfamethoxazole, carbamazepine, diclofenac, benzotriazole, tolyltriazole, iopamidole and 17α-ethinylestradiol (EE2) were degraded at initial compound concentrations of 1 μg/L in tap water and matrixes with increased organic load (46 mg/L DOC). UV/chlorine AOP organic by-product forming potential was assessed for trihalomethanes (THMs) and N-Nitrosodimethylamine (NDMA). A process design was evaluated which can considerably reduce process costs, energy consumption and by-product generation from UV/HOCl AOPs. PMID:22000058

  7. Inactivation of dinoflagellate Scripsiella trochoidea in synthetic ballast water by advanced oxidation processes.

    PubMed

    Yang, Zhishan; Jiang, Wenju; Zhang, Yi; Lim, T M

    2015-01-01

    Ship-borne ballast water contributes significantly to the transfer of non-indigenous species across aquatic environments. To reduce the risk of bio-invasion, ballast water should be treated before discharge. In this study, the efficiencies of several conventional and advanced oxidation processes were investigated for potential ballast water treatment, using a marine dinoflagellate species, Scripsiella trochoidea, as the indicator organism. A stable and consistent culture was obtained and treated by ultraviolet (UV) light, ozone (O3), hydrogen peroxide (H2O2), and their various combinations. UV apparently inactivated the cells after only 10 s of irradiation, but subsequently photo-reactivation of the cells was observed for all methods involving UV. O3 exhibited 100% inactivation efficiency after 5 min treatment, while H2O2 only achieved maximum 80% inactivation in the same duration. Combined methods, e.g. UV/O3 and UV/H2O2, were found to inhibit photo-reactivation and improve treatment efficiency to some degree, indicating the effectiveness of using combined treatment processes. The total residual oxidant (TRO) levels of the methods were determined, and the results indicated that UV and O3 generated the lowest and highest TRO, respectively. The synergic effect of combined processes on TRO generation was found to be insignificant, and thus UV/O3 was recommended as a potentially suitable treatment process for ballast water. PMID:25182606

  8. Application of several advanced oxidation processes for the destruction of terephthalic acid (TPA).

    PubMed

    Thiruvenkatachari, Ramesh; Kwon, Tae Ouk; Jun, Jung Chul; Balaji, Subramanian; Matheswaran, Manickam; Moon, Il Shik

    2007-04-01

    Terephthalic acid (TPA) is widely applied as a raw material in making polyester fiber, polyethylene terephthalate (PET) bottles, polyester films, etc. TPA is toxic and is known to act as endocrine disruptor. TPA wastewater is traditionally treated by biological process and this study aims to evaluate the effectiveness of several advanced oxidation processes on TPA removal. The oxidation processes studied were: UV-TiO(2), UV-H(2)O(2), UV-H(2)O(2)-Fe, O(3), O(3)/Fe, O(3)/TiO(2), UV-O(3)-H(2)O(2)-Fe and UV-O(3)-H(2)O(2)-Fe-TiO(2). The results indicate that the time required for the complete destruction of 50 ppm of TPA can be minimized from 10h using UV-TiO(2) system, to less than 10 min by UV-H(2)O(2)-Fe-O(3) system. Some of the likely organic intermediates identified during TPA destruction include, benzoquinone, benzene, maleic acid and oxalic acid. Possible destruction pathway of TPA has been proposed. TPA degradation by various systems was also analyzed based on the reaction kinetics and operating costs. PMID:17023113

  9. Unexpected toxicity to aquatic organisms of some aqueous bisphenol A samples treated by advanced oxidation processes.

    PubMed

    Tišler, Tatjana; Erjavec, Boštjan; Kaplan, Renata; Şenilă, Marin; Pintar, Albin

    2015-01-01

    In this study, photocatalytic and catalytic wet-air oxidation (CWAO) processes were used to examine removal efficiency of bisphenol A from aqueous samples over several titanate nanotube-based catalysts. Unexpected toxicity of bisphenol A (BPA) samples treated by means of the CWAO process to some tested species was determined. In addition, the CWAO effluent was recycled five- or 10-fold in order to increase the number of interactions between the liquid phase and catalyst. Consequently, the inductively coupled plasma mass spectrometry (ICP-MS) analysis indicated higher concentrations of some toxic metals like chromium, nickel, molybdenum, silver, and zinc in the recycled samples in comparison to both the single-pass sample and the photocatalytically treated solution. The highest toxicity of five- and 10-fold recycled solutions in the CWAO process was observed in water fleas, which could be correlated to high concentrations of chromium, nickel, and silver detected in tested samples. The obtained results clearly demonstrated that aqueous samples treated by means of advanced oxidation processes should always be analyzed using (i) chemical analyses to assess removal of BPA and total organic carbon from treated aqueous samples, as well as (ii) a battery of aquatic organisms from different taxonomic groups to determine possible toxicity. PMID:26114268

  10. Solar-Enhanced Advanced Oxidation Processes for Water Treatment: Simultaneous Removal of Pathogens and Chemical Pollutants

    PubMed Central

    Tsydenova, Oyuna; Batoev, Valeriy; Batoeva, Agniya

    2015-01-01

    The review explores the feasibility of simultaneous removal of pathogens and chemical pollutants by solar-enhanced advanced oxidation processes (AOPs). The AOPs are based on in-situ generation of reactive oxygen species (ROS), most notably hydroxyl radicals •OH, that are capable of destroying both pollutant molecules and pathogen cells. The review presents evidence of simultaneous removal of pathogens and chemical pollutants by photocatalytic processes, namely TiO2 photocatalysis and photo-Fenton. Complex water matrices with high loads of pathogens and chemical pollutants negatively affect the efficiency of disinfection and pollutant removal. This is due to competition between chemical substances and pathogens for generated ROS. Other possible negative effects include light screening, competitive photon absorption, adsorption on the catalyst surface (thereby inhibiting its photocatalytic activity), etc. Besides, some matrix components may serve as nutrients for pathogens, thus hindering the disinfection process. Each type of water/wastewater would require a tailor-made approach and the variables that were shown to influence the processes—catalyst/oxidant concentrations, incident radiation flux, and pH—need to be adjusted in order to achieve the required degree of pollutant and pathogen removal. Overall, the solar-enhanced AOPs hold promise as an environmentally-friendly way to substitute or supplement conventional water/wastewater treatment, particularly in areas without access to centralized drinking water or sewage/wastewater treatment facilities. PMID:26287222

  11. Comparison of various advanced oxidation processes for the degradation of phenylurea herbicides.

    PubMed

    Kovács, Krisztina; Farkas, János; Veréb, Gábor; Arany, Eszter; Simon, Gergő; Schrantz, Krisztina; Dombi, András; Hernádi, Klára; Alapi, Tünde

    2016-01-01

    Various types of advanced oxidation processes (AOPs), such as UV photolysis, ozonation, heterogeneous photocatalysis and their combinations were comparatively examined at the same energy input in a home-made reactor. The oxidative transformations of the phenylurea herbicides fenuron, monuron and diuron were investigated. The initial rates of transformation demonstrated that UV photolysis was highly efficient in the cases of diuron and monuron. Ozonation proved to be much more effective in the transformation of fenuron than in those of the chlorine containing monuron and diuron. In heterogeneous photocatalysis, the rate of decomposition decreased with increase of the number of chlorine atoms in the target molecule. Addition of ozone to UV-irradiated solutions and/or TiO2-containing suspensions markedly increased the initial rates of degradation. Dehalogenation of monuron and diuron showed that each of these procedures is suitable for the simultaneous removal of chlorinated pesticides and their chlorinated intermediates. Heterogeneous photocatalysis was found to be effective in the mineralization. PMID:26764571

  12. Bioassays as a tool for evaluating advanced oxidation processes in water and wastewater treatment.

    PubMed

    Rizzo, Luigi

    2011-10-01

    Advanced oxidation processes (AOPs) have been widely used in water and wastewater treatment for the removal of organic and inorganic contaminants as well as to improve biodegradability of industrial wastewater. Unfortunately, the partial oxidation of organic contaminants may result in the formation of intermediates more toxic than parent compounds. In order to avoid this drawback, AOPs are expected to be carefully operated and monitored, and toxicity tests have been used to evaluate whether effluent detoxification takes place. In the present work, the effect of AOPs on the toxicity of aqueous solutions of different classes of contaminants as well as actual aqueous matrices are critically reviewed. The dualism toxicity-biodegradability when AOPs are used as pre-treatment step to improve industrial wastewater biodegradability is also discussed. The main conclusions/remarks include the followings: (i) bioassays are a really useful tool to evaluate the dangerousness of AOPs as well as to set up the proper operative conditions, (ii) target organisms for bioassays should be chosen according to the final use of the treated water matrix, (iii) acute toxicity tests may be not suitable to evaluate toxicity in the presence of low/realistic concentrations of target contaminants, so studies on chronic effects should be further developed, (iv) some toxicity tests may be not useful to evaluate biodegradability potential, in this case more suitable tests should be applied (e.g., activated sludge bioassays, respirometry). PMID:21722938

  13. Chemical and toxicological evaluation of transformation products during advanced oxidation processes.

    PubMed

    vom Eyser, C; Börgers, A; Richard, J; Dopp, E; Janzen, N; Bester, K; Tuerk, J

    2013-01-01

    The entry of pharmaceuticals into the water cycle from sewage treatment plants is of growing concern because environmental effects are evident at trace levels. Ozonation, UV- and UV/H(2)O(2)-treatment were tested as an additional step in waste water treatment because they have been proven to be effective in eliminating aqueous organic contaminants. The pharmaceuticals carbamazepine, ciprofloxacin, diclofenac, metoprolol and sulfamethoxazole as well as the personal care products galaxolide and tonalide were investigated in terms of degradation efficiency and by-product formation in consideration of toxic effects. The substances were largely removed from treatment plant effluent by ozonation, UV- and UV/H(2)O(2)-treatment. Transformation products were detected in all tested treatment processes. Accompanying analysis showed no genotoxic, cytotoxic or estrogenic potential for the investigated compounds after oxidative treatment of real waste waters. The results indicate that by-product formation from ozonation and advanced oxidation processes does not have any negative environmental impact. PMID:24225097

  14. Amorphous mixed-metal hydroxide nanostructures for advanced water oxidation catalysts.

    PubMed

    Gao, Y Q; Liu, X Y; Yang, G W

    2016-03-01

    The design of highly efficient, durable, and earth-abundant catalysts for the oxygen evolution reaction (OER) is crucial in order to promote energy conversion and storage processes. Here, we synthesize amorphous mixed-metal (Ni-Fe) hydroxide nanostructures with a homogeneous distribution of Ni/Fe as well as a tunable Ni/Fe ratio by a simple, facile, green and low-cost electrochemical technique, and we demonstrate that the synthesized amorphous nanomaterials possess ultrahigh activity and super long-term cycle stability in the OER process. The amorphous Ni0.71Fe0.29(OH)x nanostructure affords a current density of 10 mA cm(-2) at an overpotential of a mere 0.296 V and a small Tafel slope of 58 mV dec(-1), while no deactivation is detected in the CV testing even up to 30 000 cycles, which suggests the promising application of these amorphous nanomaterials in electrochemical oxidation. Meanwhile, the distinct catalytic activities among these amorphous Ni-Fe hydroxide nanostructures prompts us to take notice of the composition of the alloy hydroxides/oxides when studying their catalytic properties, which opens an avenue for the rational design and controllable preparation of such amorphous nanomaterials as advanced OER electrocatalysts. PMID:26864279

  15. Advanced oxidation degradation kinetics as a function of ultraviolet LED duty cycle.

    PubMed

    Duckworth, Kelsey; Spencer, Michael; Bates, Christopher; Miller, Michael E; Almquist, Catherine; Grimaila, Michael; Magnuson, Matthew; Willison, Stuart; Phillips, Rebecca; Racz, LeeAnn

    2015-01-01

    Ultraviolet (UV) light emitting diodes (LEDs) may be a viable option as a UV light source for advanced oxidation processes (AOPs) utilizing photocatalysts or oxidizing agents such as hydrogen peroxide. The effect of UV-LED duty cycle, expressed as the percentage of time the LED is powered, was investigated in an AOP with hydrogen peroxide, using methylene blue (MB) to assess contaminant degradation. The UV-LED AOP degraded the MB at all duty cycles. However, adsorption of MB onto the LED emitting surface caused a linear decline in reactor performance over time. With regard to the effect of duty cycle, the observed rate constant of MB degradation, after being adjusted to account for the duty cycle, was greater for 5 and 10% duty cycles than higher duty cycles, providing a value approximately 160% higher at 5% duty cycle than continuous operation. This increase in adjusted rate constant at low duty cycles, as well as contaminant fouling of the LED surface, may impact design and operational considerations for pulsed UV-LED AOP systems. PMID:25945855

  16. Combination of Advanced Oxidation Processes and biological treatments for wastewater decontamination--a review.

    PubMed

    Oller, I; Malato, S; Sánchez-Pérez, J A

    2011-09-15

    Nowadays there is a continuously increasing worldwide concern for development of alternative water reuse technologies, mainly focused on agriculture and industry. In this context, Advanced Oxidation Processes (AOPs) are considered a highly competitive water treatment technology for the removal of those organic pollutants not treatable by conventional techniques due to their high chemical stability and/or low biodegradability. Although chemical oxidation for complete mineralization is usually expensive, its combination with a biological treatment is widely reported to reduce operating costs. This paper reviews recent research combining AOPs (as a pre-treatment or post-treatment stage) and bioremediation technologies for the decontamination of a wide range of synthetic and real industrial wastewater. Special emphasis is also placed on recent studies and large-scale combination schemes developed in Mediterranean countries for non-biodegradable wastewater treatment and reuse. The main conclusions arrived at from the overall assessment of the literature are that more work needs to be done on degradation kinetics and reactor modeling of the combined process, and also dynamics of the initial attack on primary contaminants and intermediate species generation. Furthermore, better economic models must be developed to estimate how the cost of this combined process varies with specific industrial wastewater characteristics, the overall decontamination efficiency and the relative cost of the AOP versus biological treatment. PMID:20956012

  17. Recent Advances in Superparamagnetic Iron Oxide Nanoparticles for Cellular Imaging and Targeted Therapy Research

    PubMed Central

    Wang, Yi-Xiang J.; Xuan, Shouhu; Port, Marc; Idee, Jean-Marc

    2013-01-01

    Advances of nanotechnology have led to the development of nanomaterials with both potential diagnostic and therapeutic applications. Among them, superparamagnetic iron oxide (SPIO) nanoparticles have received particular attention. Over the past decade, various SPIOs with unique physicochemical and biological properties have been designed by modifying the particle structure, size and coating. This article reviews the recent advances in preparing SPIOs with novel properties, the way these physicochemical properties of SPIOs influence their interaction with cells, and the development of SPIOs in liver and lymph nodes magnetic resonance imaging (MRI) contrast. Cellular uptake of SPIO can be exploited in a variety of potential clinical applications, including stem cell and inflammation cell tracking and intra-cellular drug delivery to cancerous cells which offers higher intra-cellular concentration. When SPIOs are used as carrier vehicle, additional advantages can be achieved including magnetic targeting and hyperthermia options, as well as monitoring with MRI. Other potential applications of SPIO include magnetofection and gene delivery, targeted retention of labeled stem cells, sentinel lymph nodes mapping, and magnetic force targeting and cell orientation for tissue engineering. PMID:23621536

  18. Development of Nonalcoholic Hepatopathy: Contributions of Oxidative Stress and Advanced Glycation End Products

    PubMed Central

    Santos, Juliana Célia de F.; Valentim, Iara B.; de Araújo, Orlando R. P.; Ataide, Terezinha da R.; Goulart, Marília O. F.

    2013-01-01

    Advanced glycation end products (AGEs) are generated spontaneously in cells; however, under conditions of hyperglycemia and lipid peroxidation, their levels are higher than usual, which contribute to the development of diseases such as the nonalcoholic fatty liver disease (NAFLD). NAFLD is associated with oxidative stress (OS), which is linked to the transition of steatosis to steatohepatitis due to lipid peroxidation. The AGE-receptor interaction in hepatic stellate cells leads to an increase in reactive oxygen species and enhances the proliferation and activation of these cells, worsening liver fibrosis and disease progression. In this vicious cycle, there is production of (carboxymethyl)lysine, a biomarker for products of advanced glycation and lipid peroxidation, being a shared component between the two pathways. In this review, we aim to compile evidence to support the basic molecular mechanisms of AGEs and OS generation and their influence, independently or combined, on the evolution of NAFLD. The deeper understanding of the interrelations of AGEs + OS may help to elucidate the pathogenic pathways of NAFLD and to devise rational therapeutic interventions for this disease, with an expected positive impact on quality of life of patients. PMID:24084729

  19. Degradation of sodium dodecyl sulphate in water using solar driven Fenton-like advanced oxidation processes.

    PubMed

    Bandala, Erick R; Peláez, Miguel A; Salgado, Maria J; Torres, Luis

    2008-03-01

    Synthetic wastewater samples containing a model surfactant were treated using two different Fenton-like advanced oxidation processes promoted by solar radiation; the photo-Fenton reaction and Co/PMS/UV processes. Comparison between the different experimental conditions was performed by means of the overall surfactant degradation achieved and by obtaining the initial rate in the first 15 min of reaction (IR15). It was found that, for dark Fenton reaction, the maximum surfactant degradation achieved was 14% under low iron and oxidant concentration. Increasing Fenton reagents by one magnitude order, surfactant degradation achieved 63% in 60 min. The use of solar radiation improved the reaction rate by 17% under same conditions and an additional increase of 12.5% was obtained by adjusting initial pH to 2. IR15 values for dark and irradiated Fenton reactions were 0.143 and 0.154 mmol/min, respectively, for similar reaction conditions and this value increased to 0.189 mmol/min when initial pH was adjusted. The use of the Co/PMS system allow us to determine an increase in the degradation rate, for low reaction conditions (1 mM of transition metal; 4 mM oxidant) similar to those used in dark Fenton reaction. Surfactant degradation increased from 3%, for Fenton reaction, to 44.5% in the case of Co/PMS. When solar irradiation was included in the experiments, under same reaction conditions described earlier, surfactant degradation up to 64% was achieved. By increasing Co/PMS reagent concentration by almost 9 times under irradiated conditions, almost complete (>99%) surfactant degradation was reached in 5 min. Comparing IR15 values for Co/PMS and Co/PMS/UV, it allow us to observe that the use of solar radiation increased the degradation rate in one magnitude order when compared with dark experiments and further increase of reagent concentration increased reaction rate twice. PMID:17658215

  20. Identification of C1q as a Binding Protein for Advanced Glycation End Products.

    PubMed

    Chikazawa, Miho; Shibata, Takahiro; Hatasa, Yukinori; Hirose, Sayumi; Otaki, Natsuki; Nakashima, Fumie; Ito, Mika; Machida, Sachiko; Maruyama, Shoichi; Uchida, Koji

    2016-01-26

    Advanced glycation end products (AGEs) make up a heterogeneous group of molecules formed from the nonenzymatic reaction of reducing sugars with the free amino groups of proteins. The abundance of AGEs in a variety of age-related diseases, including diabetic complications and atherosclerosis, and their pathophysiological effects suggest the existence of innate defense mechanisms. Here we examined the presence of serum proteins that are capable of binding glycated bovine serum albumin (AGEs-BSA), prepared upon incubation of BSA with dehydroascorbate, and identified complement component C1q subcomponent subunit A as a novel AGE-binding protein in human serum. A molecular interaction analysis showed the specific binding of C1q to the AGEs-BSA. In addition, we identified DNA-binding regions of C1q, including a collagen-like domain, as the AGE-binding site and established that the amount of positive charge on the binding site was the determining factor. C1q indeed recognized several other modified proteins, including acylated proteins, suggesting that the binding specificity of C1q might be ascribed, at least in part, to the electronegative potential of the ligand proteins. We also observed that C1q was involved in the AGEs-BSA-activated deposition of complement proteins, C3b and C4b. In addition, the AGEs-BSA mediated the proteolytic cleavage of complement protein 5 to release C5a. These findings provide the first evidence of AGEs as a new ligand recognized by C1q, stimulating the C1q-dependent classical complement pathway. PMID:26731343

  1. Manufacture and engine test of advanced oxide dispersion strengthened alloy turbine vanes. [for space shuttle thermal protection

    NASA Technical Reports Server (NTRS)

    Bailey, P. G.

    1977-01-01

    Oxide-Dispersion-strengthened (ODS) Ni-Cr-Al alloy systems were exploited for turbine engine vanes which would be used for the space shuttle thermal protection system. Available commercial and developmental advanced ODS alloys were evaluated, and three were selected based on established vane property goals and manufacturing criteria. The selected alloys were evaluated in an engine test. Candidate alloys were screened by strength, thermal fatigue resistance, oxidation and sulfidation resistance. The Ni-16Cr (3 to 5)Al-ThO2 system was identified as having attractive high temperature oxidation resistance. Subsequent work also indicated exceptional sulfidation resistance for these alloys.

  2. Lipid and protein oxidation contribute to a prothrombotic state in patients with type 2 diabetes mellitus.

    PubMed

    De Cristofaro, R; Rocca, B; Vitacolonna, E; Falco, A; Marchesani, P; Ciabattoni, G; Landolfi, R; Patrono, C; Davì, G

    2003-02-01

    Diabetes mellitus (DM) is associated with enhanced lipid oxidation and persistent platelet activation. We investigated whether oxidant stress (OS) also affects circulating proteins and is associated with an abnormal coagulative pattern. In 72 type 2 DM (T2DM) patients, urinary 8-iso-prostaglandin (PG) F2alpha and 11-dehydro-thromboxane B2 (TXM) were measured as markers of lipid peroxidation and platelet activation, respectively. The carbonyl content of plasma proteins (PCARB) was measured as global index of protein oxidation. 8-Iso-PGF2alpha and PCARB levels were higher in DM patients than in controls (P < 0.05). Likewise, both TXM and prothrombin F1+2 levels were higher in diabetics (P < 0.05). By contrast, anticoagulant markers, such as activated protein C, protein C activation peptide, and soluble thrombomodulin (TM) were depressed in T2DM (P < 0.05). In conclusion, OS in T2DM involves circulating proteins and is associated with an unbalanced promotion of procoagulant reactions. These effects in concert with platelet activation may contribute to atherothrombotic complications in T2DM. PMID:12871497

  3. Adsorption kinetics of plasma proteins on ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles.

    PubMed

    Jansch, M; Stumpf, P; Graf, C; Rühl, E; Müller, R H

    2012-05-30

    In this study the kinetics of plasma protein adsorption onto ultrasmall superparamagnetic iron oxide (USPIO) particles have been analyzed and compared to previously published kinetic studies on polystyrene particles (PS particles), oil-in-water nanoemulsions and solid lipid nanoparticles (SLNs). SPIO and USPIO nanoparticles are commonly used as magnetic resonance imaging (MRI) enhancers for tumor imaging as well as in drug delivery applications. Two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) has been used to determine the plasma protein adsorption onto the citrate/triethylene glycol-stabilized iron oxide surface. The results indicate that the existence of a Vroman effect, a displacement of previously adsorbed abundant proteins, such as albumin or fibrinogen, respectively, on USPIO particles has to be denied. Previously, identical findings have been reported for oil-in-water nanoemulsions. Furthermore, the protein adsorption kinetics differs dramatically from that of other solid drug delivery systems (PS, SLN). More relevant for the in vivo fate of long circulating particles is the protein corona after several minutes or even hours. Interestingly, the patterns received after an incubation time of 0.5 min to 240 min are found to be qualitatively and quantitatively similar. This leads to the assumption of a long-lived ("hard") protein corona around the iron oxide nanoparticles. PMID:22342465

  4. Ferrous iron oxidation by sulfur-oxidizing Acidithiobacillus ferrooxidans and analysis of the process at the levels of transcription and protein synthesis.

    PubMed

    Kucera, Jiri; Bouchal, Pavel; Lochman, Jan; Potesil, David; Janiczek, Oldrich; Zdrahal, Zbynek; Mandl, Martin

    2013-04-01

    In contrast to iron-oxidizing Acidithiobacillus ferrooxidans, A. ferrooxidans from a stationary phase elemental sulfur-oxidizing culture exhibited a lag phase in pyrite oxidation, which is similar to its behaviour during ferrous iron oxidation. The ability of elemental sulfur-oxidizing A. ferrooxidans to immediately oxidize ferrous iron or pyrite without a lag phase was only observed in bacteria obtained from growing cultures with elemental sulfur. However, these cultures that shifted to ferrous iron oxidation showed a low rate of ferrous iron oxidation while no growth was observed. Two-dimensional gel electrophoresis was used for a quantitative proteomic analysis of the adaptation process when bacteria were switched from elemental sulfur to ferrous iron. A comparison of total cell lysates revealed 39 proteins whose increase or decrease in abundance was related to this phenotypic switching. However, only a few proteins were closely related to iron and sulfur metabolism. Reverse-transcription quantitative PCR was used to further characterize the bacterial adaptation process. The expression profiles of selected genes primarily involved in the ferrous iron oxidation indicated that phenotypic switching is a complex process that includes the activation of genes encoding a membrane protein, maturation proteins, electron transport proteins and their regulators. PMID:23291738

  5. Highly sensitive detection for proteins using graphene oxide-aptamer based sensors

    NASA Astrophysics Data System (ADS)

    Gao, Li; Li, Qin; Li, Raoqi; Yan, Lirong; Zhou, Yang; Chen, Keping; Shi, Haixia

    2015-06-01

    In recent years, the detection of proteins by using bare graphene oxide (GO) to quench the fluorescence of fluorescein-labeled aptamers has been reported. However, the proteins can be adsorbed on the surface of bare GO to prevent the sensitivity from further being improved. In order to solve this problem, polyethylene glycol (PEG)-protected GO was used to prevent the proteins using thrombin as an example from nonspecific binding. The detection limit was improved compared to bare GO under the optimized ratio of GO to PEG concentration. The results show that our method is a promising technique for the detection of proteins.In recent years, the detection of proteins by using bare graphene oxide (GO) to quench the fluorescence of fluorescein-labeled aptamers has been reported. However, the proteins can be adsorbed on the surface of bare GO to prevent the sensitivity from further being improved. In order to solve this problem, polyethylene glycol (PEG)-protected GO was used to prevent the proteins using thrombin as an example from nonspecific binding. The detection limit was improved compared to bare GO under the optimized ratio of GO to PEG concentration. The results show that our method is a promising technique for the detection of proteins. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr01187f

  6. Photoaging is associated with protein oxidation in human skin in vivo.

    PubMed

    Sander, Christina S; Chang, Hong; Salzmann, Susann; Müller, Cornelia S L; Ekanayake-Mudiyanselage, Swarna; Elsner, Peter; Thiele, Jens J

    2002-04-01

    There is increasing evidence for the generation of reactive oxygen species in skin upon ultraviolet exposure, but little is known about their pathophysiologic relevance in human skin in vivo. We hypothesized that chronic and acute photodamage is mediated by depleted antioxidant enzyme expression and increased oxidative protein modifications. Biopsies from patients with histologically confirmed solar elastosis, from non-ultraviolet-exposed sites of age-matched controls, and from young subjects were analyzed. To evaluate the influence of acute ultraviolet exposures, buttock skin of 12 healthy subjects was irradiated repetitively on 10 d with a solar simulator and compared intraindividually to non-ultraviolet-treated contralateral sites. The antioxidant enzymes catalase, copper-zinc superoxide dismutase, and manganese superoxide dismutase were investigated by immunohistochemistry. Protein carbonyls were analyzed by immunohistochemical and immunoblotting techniques in human skin and in cell models. Whereas overall expression of antioxidant enzymes was very high in the epidermis, low baseline levels were found in the dermis. In photoaged skin, a significant depletion of antioxidant enzyme expression was observed within the stratum corneum and in the epidermis. Importantly, an accumulation of oxidatively modified proteins was found specifically within the upper dermis of photoaged skin. Upon acute ultraviolet exposure of healthy subjects, depleted catalase expression and increased protein oxidation were detected. Exposures of keratinocytes and fibroblasts to ultraviolet B, ultraviolet A, and H2O2 led to dose-dependent protein oxidation and thus confirmed in vivo results. In conclusion, the correlation between photodamage and protein oxidation was demonstrated for the first time, which hence may be a relevant pathophysiologic factor in photoaging. PMID:11918707

  7. Cloning and expression of a cell surface receptor for advanced glycosylation end products of proteins.

    PubMed

    Neeper, M; Schmidt, A M; Brett, J; Yan, S D; Wang, F; Pan, Y C; Elliston, K; Stern, D; Shaw, A

    1992-07-25

    Advanced glycosylation end products of proteins (AGEs) are nonenzymatically glycosylated proteins which accumulate in vascular tissue in aging and at an accelerated rate in diabetes. A approximately 35-kDa polypeptide with a unique NH2-terminal sequence has been isolated from bovine lung and found to be present on the surface of endothelial cells where it mediates the binding of AGEs (receptor for advanced glycosylation end product or RAGE). Using an oligonucleotide probe based on the amino-terminal sequence of RAGE, an apparently full-length cDNA of 1.5 kilobases was isolated from a bovine lung cDNA library. This cDNA encoded a 394 amino acid mature protein comprised of the following putative domains: an extracellular domain of 332 amino acids, a single hydrophobic membrane spanning domain of 19 amino acids, and a carboxyl-terminal domain of 43 amino acids. A partial clone encoding the human counterpart of RAGE, isolated from a human lung library, was found to be approximately 90% homologous to the bovine molecule. Based on computer analysis of the amino acid sequence of RAGE and comparison with databases, RAGE is a new member of the immunoglobulin superfamily of cell surface molecules and shares significant homology with MUC 18, NCAM, and the cytoplasmic domain of CD20. Expression of the RAGE cDNA in 293 cells allowed them to bind 125I-AGE-albumin in a saturable and dose-dependent manner (Kd approximately 100 nM), blocked by antibody to RAGE. Western blots of 293 cells transfected with RAGE cDNA probed with anti-RAGE IgG demonstrated expression of immunoreactive protein compared to its absence in mock-transfected cells. These results suggest that RAGE functions as a cell surface receptor for AGEs, which could potentially mediate cellular effects of this class of glycosylated proteins. PMID:1378843

  8. Development of Advanced Atherosclerotic Plaque by Injection of Inflammatory Proteins in a Rabbit Iliac Artery Model

    PubMed Central

    Kim, Jung-Sun; Lee, Seul-Gee; Oh, Jaewon; Park, Se-Il; Hong, Sung-Yu; Kim, Sehoon; Lee, Sang-Hak; Ko, Young-Guk; Choi, Donghoon; Hong, Myeong-Ki; Jang, Yangsoo

    2016-01-01

    Purpose Appropriate animal models of atherosclerotic plaque are crucial to investigating the pathophysiology of atherosclerosis, as well as for the evaluation of the efficacy and safety of vascular devices. We aimed to develop a novel animal model that would be suitable for the study of advanced atherosclerotic lesions in vivo. Materials and Methods Atherosclerotic plaque was induced in 24 iliac arteries from 12 rabbits by combining a high cholesterol diet, endothelial denudation, and injection into the vessel wall with either saline (n=5), olive oil (n=6), or inflammatory proteins [n=13, high-mobility group protein B1 (HMGB1) n=8 and tumor necrosis factor (TNF)-α n=5] using a Cricket™ Micro-infusion catheter. Optical coherence tomography (OCT) was performed to detect plaque characteristics after 4 weeks, and all tissues were harvested for histological evaluation. Results Advanced plaque was more frequently observed in the group injected with inflammatory proteins. Macrophage infiltration was present to a higher degree in the HMGB1 and TNF-α groups, compared to the oil or saline group (82.1±5.1% and 94.6±2.2% compared to 49.6±14.0% and 46.5±9.6%, p-value<0.001), using RAM11 antibody staining. On OCT, lipid rich plaques were more frequently detected in the inflammatory protein group [saline group: 2/5 (40%), oil group: 3/5 (50%), HMGB1 group: 6/8 (75%), and TNF-α group: 5/5 (100%)]. Conclusion These data indicate that this rabbit model of atherosclerotic lesion formation via direct injection of pro-inflammatory proteins into the vessel wall is useful for in vivo studies investigating atherosclerosis. PMID:27401639

  9. Advances in Mammalian Cell Line Development Technologies for Recombinant Protein Production

    PubMed Central

    Lai, Tingfeng; Yang, Yuansheng; Ng, Say Kong

    2013-01-01

    From 2006 to 2011, an average of 15 novel recombinant protein therapeutics have been approved by US Food and Drug Administration (FDA) annually. In addition, the expiration of blockbuster biologics has also spurred the emergence of biosimilars. The increasing numbers of innovator biologic products and biosimilars have thus fuelled the demand of production cell lines with high productivity. Currently, mammalian cell line development technologies used by most biopharmaceutical companies are based on either the methotrexate (MTX) amplification technology or the glutamine synthetase (GS) system. With both systems, the cell clones obtained are highly heterogeneous, as a result of random genome integration by the gene of interest and the gene amplification process. Consequently, large numbers of cell clones have to be screened to identify rare stable high producer cell clones. As such, the cell line development process typically requires 6 to 12 months and is a time, capital and labour intensive process. This article reviews established advances in protein expression and clone screening which are the core technologies in mammalian cell line development. Advancements in these component technologies are vital to improve the speed and efficiency of generating robust and highly productive cell line for large scale production of protein therapeutics. PMID:24276168

  10. Plasma levels of oxidative stress-responsive apoptosis inducing protein (ORAIP) in rats subjected to physicochemical oxidative stresses.

    PubMed

    Yao, Takako; Fujimura, Tsutomu; Murayama, Kimie; Seko, Yoshinori

    2016-01-01

    Oxidative stress is known to play a pivotal role in the pathogenesis of various disorders including atherosclerosis, aging and especially ischaemia/reperfusion injury. It causes cell damage that leads to apoptosis. However, the precise mechanism has been uncertain. Recently, we identified an apoptosis-inducing humoral factor in a hypoxia/reoxygenated medium of cardiac myocytes. We named this novel post-translationally modified secreted form of eukaryotic translation initiation factor 5A (eIF5A) as oxidative stress-responsive apoptosis inducing protein (ORAIP). We developed a sandwich ELISA and confirmed that myocardial ischaemia/reperfusion markedly increased plasma levels of ORAIP. To investigate whether the role of ORAIP is common to various types of oxidative stress, we measured plasma ORAIP levels in rats subjected to three physicochemical models of oxidative stress including N2/O2 inhalation, cold/warm-stress (heat shock) and blood acidification. In all three models, plasma ORAIP levels significantly increased and reached a peak level at 10-30 min after stimulation, then decreased within 60 min. The (mean±S.E.M.) plasma ORAIP levels before and after (peak) stimulation were (16.4±9.6) and (55.2±34.2) ng/ml in N2/O2 inhalation, (14.1±12.4) and (34.3±14.6) ng/ml in cold/warm-stress, and (18.9±14.3) and (134.0±67.2) ng/ml in blood acidification study. These data strongly suggest that secretion of ORAIP in response to oxidative stress is universal mechanism and plays an essential role. ORAIP will be an important novel biomarker as well as a specific therapeutic target of these oxidative stress-induced cell injuries. PMID:26934977

  11. Mass spectrometric quantification of amino acid oxidation products in proteins: insights into pathways that promote LDL oxidation in the human artery wall.

    PubMed

    Heinecke, J W

    1999-07-01

    Oxidatively damaged low density lipoprotein (LDL) may play an important role in atherogenesis, but the physiologically relevant pathways have proved difficult to identify. Mass spectrometric quantification of stable compounds that result from specific oxidation reactions represents a powerful approach for investigating such mechanisms. Analysis of protein oxidation products isolated from atherosclerotic lesions implicates tyrosyl radical, reactive nitrogen species, and hypochlorous acid in LDL oxidation in the human artery wall. These observations provide chemical evidence for the reaction pathways that promote LDL oxidation and lesion formation in vivo.--Heinecke, J. W. Mass spectrometric quantification of amino acid oxidation products in proteins: insights into pathways that promote LDL oxidation in the human artery wall. PMID:10385603

  12. Effect of sodium ascorbate and sodium nitrite on protein and lipid oxidation in dry fermented sausages.

    PubMed

    Berardo, A; De Maere, H; Stavropoulou, D A; Rysman, T; Leroy, F; De Smet, S

    2016-11-01

    The effects of sodium nitrite and ascorbate on lipid and protein oxidation were studied during the ripening process of dry fermented sausages. Samples were taken at day 0, 2, 8, 14, 21 and 28 of ripening to assess lipid (malondialdehyde) and protein (carbonyls and sulfhydryl groups) oxidation. Sodium ascorbate and nitrite were separately able to reduce the formation of malondialdehyde. Their combined addition resulted in higher amounts of carbonyl compounds compared to their separate addition or the treatment without any of both compounds. Moreover, sodium nitrite limited the formation of γ-glutamic semialdehyde whereas sodium ascorbate showed a pro-oxidant effect. A loss of thiol groups was observed during ripening, which was not affected by the use of sodium ascorbate nor sodium nitrite. In conclusion, sodium nitrite and ascorbate affected protein and lipid oxidation in different manners. The possible pro-oxidant effect of their combined addition on carbonyl formation might influence the technological and sensory properties of these products. PMID:27424306

  13. Oxidative stress and hepatic Nox proteins in chronic hepatitis C and hepatocellular carcinoma

    PubMed Central

    Choi, Jinah; Corder, Nicole L. B.; Koduru, Bhargav; Wang, Yiyan

    2014-01-01

    Hepatocellular carcinoma (HCC) is the most common liver cancer and a leading cause of cancer-related mortality in the world. Hepatitis C virus (HCV) is a major etiologic agent of HCC. A majority of HCV infections lead to chronic infection that can progress to cirrhosis and eventually, HCC and liver failure. A common pathogenic feature present in HCV infection, and other conditions leading to HCC, is oxidative stress. HCV directly increases superoxide and H2O2 formation in hepatocytes by elevating Nox protein expression and sensitizing mitochondria to reactive oxygen species generation while decreasing glutathione. Nitric oxide synthesis and hepatic iron are also elevated. Furthermore, activation of phagocytic NADPH oxidase 2 (Nox2) of host immune cells is likely to exacerbate oxidative stress in HCV-infected patients. Key mechanisms of HCC include: genome instability, epigenetic regulation, inflammation with chronic tissue injury and sustained cell proliferation, and modulation of cell growth and death. Oxidative stress, or Nox proteins, plays various roles in these mechanisms. Nox proteins also function in hepatic fibrosis, which commonly precedes HCC, and Nox4 elevation by HCV was mediated by transforming growth factor beta. This review summarizes mechanisms of oncogenesis by HCV, highlighting the role of oxidative stress and hepatic Nox enzymes in HCC. PMID:24816297

  14. ADVANCED OXIDATION PROCESSES (AOPS) FOR DESTRUCTION OF METHYL TERTIARY BUTYL ETHER (MTBE -AN UNREGULATED CONTAMINANT) IN DRINKING WATER

    EPA Science Inventory

    Advanced oxidation processes (AOPs) provide a promising treatment option for the destruction of MTBE directly in surface and ground waters. An ongoing study is evaluating the ability of three AOPs; hydrogen peroxide/ozone (H2O2/ O3), ultraviolet irradiation/ozone (UV/O3) and ultr...

  15. Effect Of Inorganic, Synthetic And Naturally Occurring Chelating Agents On Fe(II) Mediated Advanced Oxidation Of Chlorophenols

    EPA Science Inventory

    This study examines the feasibility and application of Advanced Oxidation Technologies (AOTs) for the treatment of chlorophenols that are included in US EPA priority pollutant list. A novel class of sulfate/hydroxyl radical-based homogeneous AOTs (Fe(II)/PS, Fe(II)/PMS, Fe(II)/H...

  16. Anesthesia with halothane and nitrous oxide alters protein and amino acid metabolism in dogs

    SciTech Connect

    Horber, F.F.; Krayer, S.; Rehder, K.; Haymond, M.W.

    1988-09-01

    General anesthesia in combination with surgery is known to result in negative nitrogen balance. To determine whether general anesthesia without concomitant surgery decreases whole body protein synthesis and/or increases whole body protein breakdown, two groups of dogs were studied: Group 1 (n = 6) in the conscious state and Group 2 (n = 8) during general anesthesia employing halothane (1.5 MAC) in 50% nitrous oxide and oxygen. Changes in protein metabolism were estimated by isotope dilution techniques employing simultaneous infusions of (4,53H)leucine and alpha-(1-14C)-ketoisocaproate (KIC). Total leucine carbon flux was unchanged or slightly increased in the anesthetized animals when compared to the conscious controls, indicating only a slight increase in the rate of proteolysis. However, leucine oxidation was increased (P less than 0.001) by more than 80% in the anesthetized animals when compared with their conscious controls, whereas whole body nonoxidative leucine disappearance, an indicator of whole body protein synthesis, was decreased. The ratio of leucine oxidation to the nonoxidative rate of leucine disappearance, which provides an index of the catabolism of at least one essential amino acid in the postabsorptive state, was more than twofold increased (P less than 0.001) in the anesthetized animals regardless of the tracer employed. These studies suggest that the administration of anesthesia alone, without concomitant surgery, is associated with a decreased rate of whole body protein synthesis and increased leucine oxidation, resulting in increased leucine and protein catabolism, which may be underlying or initiating some of the protein wasting known to occur in patients undergoing surgery.

  17. Circles within circles: crosstalk between protein Ser/Thr/Tyr-phosphorylation and Met oxidation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Reversible posttranslational protein modifications such as phosphorylation of Ser/Thr/Tyr and Met oxidation are critical for both metabolic regulation and cellular signalling. Although these modifications are typically studied individually, herein we describe the potential for cross-talk...

  18. Direct detection of nitrotyrosine-containing proteins using an aniline-based oxidative coupling strategy.

    PubMed

    Sangsuwan, Rapeepat; Obermeyer, Allie C; Tachachartvanich, Phum; Palaniappan, Krishnan K; Francis, Matthew B

    2016-08-21

    A convenient two-step method is described for the detection of nitrotyrosine-containing proteins. First, nitrotyrosines are reduced to aminophenols using sodium dithionite. Following this, an oxidative coupling reaction is used to attach anilines bearing fluorescence reporters or affinity probes. Features of this approach include fast reaction times, pmol-level sensitivity, and excellent chemoselectivity. PMID:27447346

  19. Lipid and protein oxidation in female patients with chronic fatigue syndrome

    PubMed Central

    Tomic, Slavica; Brkic, Snezana; Mikic, Aleksandra Novakov

    2012-01-01

    Introduction Chronic fatigue syndrome (CFS) is a widely recognized problem, characterized by prolonged, debilitating fatigue and a characteristic group of accompanying symptoms, that occurs four times more frequently in women than in men. The aim of the study was to determine the existence of oxidative stress and its possible consequences in female patients with CFS. Material and methods Twenty-four women aged 15-45 who fulfilled the diagnostic criteria for CFS with no comorbidities were recruited and were age matched to a control group of 19 healthy women. After conducting the routine laboratory tests, levels of the lipid oxidation product malondialdehyde (MDA) and protein oxidation protein carbonyl (CO) were determined. Results The CFS group had higher levels of triglycerides (p = 0.03), MDA (p = 0.03) and CO (p = 0.002) and lower levels of HDL cholesterol (p = 0.001) than the control group. There were no significant differences in the levels of total protein, total cholesterol or LDL cholesterol. Conclusions The CFS group had an unfavorable lipid profile and signs of oxidative stress induced damage to lipids and proteins. These results might be indicative of early proatherogenic processes in this group of patients who are otherwise at low risk for atherosclerosis. Antioxidant treatment and life style changes are indicated for women with CFS, as well as closer observation in order to assess the degree of atherosclerosis. PMID:23185200

  20. Recent advances in surface chemistry strategies for the fabrication of functional iron oxide based magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Turcheniuk, Kostiantyn; Tarasevych, Arkadii V.; Kukhar, Valeriy P.; Boukherroub, Rabah; Szunerits, Sabine

    2013-10-01

    The synthesis of superparamagnetic nanostructures, especially iron-oxide based nanoparticles (IONPs), with appropriate surface functional groups has been intensively researched for many high-technological applications, including high density data storage, biosensing and biomedicine. In medicine, IONPs are nowadays widely used as contrast agents for magnetic resonance imaging (MRI), in hyperthermia therapy, but are also exploited for drug and gene delivery, detoxification of biological fluids or immunoassays, as they are relatively non-toxic. The use of magnetic particles in vivo requires IONPs to have high magnetization values, diameters below 100 nm with overall narrow size distribution and long time stability in biological fluids. Due to the high surface energies of IONPs agglomeration over time is often encountered. It is thus of prime importance to modify their surface to prevent aggregation and to limit non-specific adsorption of biomolecules onto their surface. Such chemical modifications result in IONPs being well-dispersed and biocompatible, and allow for targeted delivery and specific interactions. The chemical nature of IONPs thus determines not only the overall size of the colloid, but also plays a significant role for in vivo and in vitro applications. This review discusses the different concepts currently used for the surface functionalization and coating of iron oxide nanoparticles. The diverse strategies for the covalent linking of drugs, proteins, enzymes, antibodies, and nucleotides will be discussed and the chemically relevant steps will be explained in detail.

  1. Nitric Oxide and Protein Disulfide Isomerase Explain the Complexities of Unfolded Protein Response Following Intra-hippocampal Aβ Injection.

    PubMed

    Khodagholi, Fariba; Digaleh, Hadi; Motamedi, Fereshteh; Foolad, Forough; Shaerzadeh, Fatemeh

    2016-08-01

    Several pathways involved in regulation of intracellular protein integrity are known as the protein quality control (PQC) system. Molecular chaperones as the main players are engaged in various aspects of PQC system. According to the importance of these proteins in cell survival, in the present study, we traced endoplasmic reticulum-specific markers and chaperone-mediated autophagy (CMA)-associated factors as two main arms of PQC system in intra-hippocampal amyloid beta (Aβ)-injected rats during 10 days running. Data analysis from Western blot indicated that exposure to Aβ activates immunoglobulin heavy-chain-binding protein (Bip) which is the upstream regulator of unfolded protein responses (UPR). Activation of UPR system eventually led to induction of pro-apoptotic factors like CHOP, calpain, and caspase-12. Moreover, our data revealed that protein disulfide isomerase activity dramatically decreased after Aβ injection, which could be attributed to the increased levels of nitric oxide. Besides, Aβ injection induced levels of 2 members of heat shock proteins (Hsp) 70 and 90. Elevated levels of Hsps family members are accompanied by increased levels of lysosome-associated membrane protein type-2A (Lamp-2A) that are involved in CMA. Despite the reduction in CHOP, calpain, caspase-12, and Lamp-2A protein levels, the levels of molecular chaperones Bip, Hsps70, and 90 increased 10 days after Aβ injection in comparison to the control group. Based on our results, 10 days after Aβ injection, despite the activation of protective chaperones, markers associated with neurotoxicity were still elevated. PMID:26391027

  2. Protective effects of zinc on oxidative stress enzymes in liver of protein-deficient rats.

    PubMed

    Sidhu, Pardeep; Garg, M L; Dhawan, D K

    2005-01-01

    Persons afflicted with protein malnutrition are generally deficient in a variety of essential micronutrients like zinc, copper, iron, and selenium, which in turn affects number of metabolic processes in the body. To evaluate the protective effects of zinc on the enzymes involved in oxidative stress induced in liver of protein-deficient rats, the current study was designed. Zinc sulfate at a dose level of 227 mg/L zinc in drinking water was administered to female Sprague-Dawley normal control as well as protein-deficient rats for a total duration of 8 weeks. The effects of zinc treatment in conditions of protein deficiency were studied on rat liver antioxidant enzymes, which included catalase, glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD), glutathione reduced (GSH), and glutathione-S-transferase (GST). Protein deficiency in normal rats resulted in a significant increase in hepatic activities of catalase, glutathione peroxidase, glutathione reductase, and glutathione-S-transferase and the levels of lipid peroxidation. A significant inhibition in the levels of reduced glutathione and the enzyme activity of superoxide dismutase has been observed after protein deficiency in normal rats. Interestingly, Zn treatment to protein-deficient animals lowered already raised activity catalase, glutathione peroxidase, and glutathione-S-transferase and levels of lipid peroxidation to significant levels when compared to protein-deficient animals. Also, Zn treatment to the protein-deficient animals resulted in a significant elevation in the levels of GSH and SOD activity as compared to their respective controls, thereby indicating its effectiveness in regulating their levels in adverse conditions. It has also been observed that concentrations of zinc, copper, iron, and selenium were found to be decreased significantly in protein-deficient animals. However, the levels of these elements came back to within normal limits when zinc was administrated

  3. Probing the paramyxovirus fusion (F) protein-refolding event from pre- to postfusion by oxidative footprinting

    PubMed Central

    Poor, Taylor A.; Jones, Lisa M.; Sood, Amika; Leser, George P.; Plasencia, Manolo D.; Rempel, Don L.; Jardetzky, Theodore S.; Woods, Robert J.; Gross, Michael L.; Lamb, Robert A.

    2014-01-01

    To infect a cell, the Paramyxoviridae family of enveloped viruses relies on the coordinated action of a receptor-binding protein (variably HN, H, or G) and a more conserved metastable fusion protein (F) to effect membrane fusion and allow genomic transfer. Upon receptor binding, HN (H or G) triggers F to undergo an extensive refolding event to form a stable postfusion state. Little is known about the intermediate states of the F refolding process. Here, a soluble form of parainfluenza virus 5 F was triggered to refold using temperature and was footprinted along the refolding pathway using fast photochemical oxidation of proteins (FPOP). Localization of the oxidative label to solvent-exposed side chains was determined by high-resolution MS/MS. Globally, metastable prefusion F is oxidized more extensively than postfusion F, indicating that the prefusion state is more exposed to solvent and is more flexible. Among the first peptides to be oxidatively labeled after temperature-induced triggering is the hydrophobic fusion peptide. A comparison of peptide oxidation levels with the values of solvent-accessible surface area calculated from molecular dynamics simulations of available structural data reveals regions of the F protein that lie at the heart of its prefusion metastability. The strong correlation between the regions of F that experience greater-than-expected oxidative labeling and epitopes for neutralizing antibodies suggests that FPOP has a role in guiding the development of targeted therapeutics. Analysis of the residue levels of labeled F intermediates provides detailed insights into the mechanics of this critical refolding event. PMID:24927585

  4. Protein S-sulfenylation is a fleeting molecular switch that regulates non-enzymatic oxidative folding

    PubMed Central

    Beedle, Amy E. M.; Lynham, Steven; Garcia-Manyes, Sergi

    2016-01-01

    The post-translational modification S-sulfenylation functions as a key sensor of oxidative stress. Yet the dynamics of sulfenic acid in proteins remains largely elusive due to its fleeting nature. Here we use single-molecule force-clamp spectroscopy and mass spectrometry to directly capture the reactivity of an individual sulfenic acid embedded within the core of a single Ig domain of the titin protein. Our results demonstrate that sulfenic acid is a crucial short-lived intermediate that dictates the protein's fate in a conformation-dependent manner. When exposed to the solution, sulfenic acid rapidly undergoes further chemical modification, leading to irreversible protein misfolding; when cryptic in the protein's microenvironment, it readily condenses with a neighbouring thiol to create a protective disulfide bond, which assists the functional folding of the protein. This mechanism for non-enzymatic oxidative folding provides a plausible explanation for redox-modulated stiffness of proteins that are physiologically exposed to mechanical forces, such as cardiac titin. PMID:27546612

  5. Micropatterning of Proteins and Mammalian Cells on Indium Tin Oxide

    PubMed Central

    Shah, Sunny S.; Howland, Michael C.; Chen, Li-Jung; Silangcruz, Jaime; Verkhoturov, Stanislav V.; Schweikert, Emile A.; Parikh, Atul N.; Revzin, Alexander

    2010-01-01

    This paper describes a novel surface engineering approach that combines oxygen plasma treatment and electrochemical activation to create micropatterned cocultures on indium tin oxide (ITO) substrates. In this approach, photoresist was patterned onto an ITO substrate modified with poly(ethylene) glycol (PEG) silane. The photoresist served as a stencil during exposure of the surface to oxygen plasma. Upon incubation with collagen (I) solution and removal of the photoresist, the ITO substrate contained collagen regions surrounded by nonfouling PEG silane. Chemical analysis carried out with time-of-flight secondary ion mass spectrometry (ToF-SIMS) at different stages in micropatterned construction verified removal of PEG-silane during oxygen plasma and presence of collagen and PEG molecules on the same surface. Imaging ellipsometry and atomic force microscopy (AFM) were employed to further investigate micropatterned ITO surfaces. Biological application of this micropatterning strategy was demonstrated through selective attachment of mammalian cells on the ITO substrate. Importantly, after seeding the first cell type, the ITO surfaces could be activated by applying negative voltage (−1.4 V vs Ag/AgCl). This resulted in removal of nonfouling PEG layer and allowed to attach another cell type onto the same surface and to create micropatterned cocultures. Micropatterned cocultures of primary hepatocytes and fibroblasts created by this strategy remained functional after 9 days as verified by analysis of hepatic albumin. The novel surface engineering strategy described here may be used to pattern multiple cell types on an optically transparent and conductive substrate and is envisioned to have applications in tissue engineering and biosensing. PMID:20356132

  6. Identification of oxidized protein hydrolase of human erythrocytes as acylpeptide hydrolase.

    PubMed

    Fujino, T; Watanabe, K; Beppu, M; Kikugawa, K; Yasuda, H

    2000-03-16

    Partial amino acid sequence of 80 kDa oxidized protein hydrolase (OPH), a serine protease present in human erythrocyte cytosol (Fujino et al., J. Biochem. 124 (1998) 1077-1085) that is adherent to oxidized erythrocyte membranes and preferentially degrades oxidatively damaged proteins (Beppu et al., Biochim. Biophys. Acta 1196 (1994) 81-87; Fujino et al., Biochim. Biophys. Acta 1374 (1998) 47-55) was determined. The N-terminal amino acid of diisopropyl fluorophosphate (DFP)-labeled OPH was suggested to be masked. Six peptide fragments of OPH obtained by digestion of DFP-labeled OPH with lysyl endopeptidase were isolated by use of reverse-phase high-performance liquid chromatography, and the sequence of more than eight amino acids from the N-terminal position of each peptide was determined. Results of homology search of amino acid sequence of each peptide strongly suggested that the protein was identical with human liver acylpeptide hydrolase (ACPH). OPH showed ACPH activity when N-acetyl-L-alanine p-nitroanilide and N-acetylmethionyl L-alanine were used as substrates. Glutathione S-transferase (GST)-tagged recombinant ACPH (rACPH) was prepared by use of baculovirus expression system as a 107-kDa protein from cDNA of human erythroleukemic cell line K-562. rACPH reacted with anti-OPH antiserum from rabbit. rACPH showed OPH activity when hydrogen peroxide-oxidized or glycated bovine serum albumin was used as substrates. As well as the enzyme activities of OPH, those of rACPH were inhibited by DFP. The results clearly demonstrate that ACPH, whose physiological function has not yet been well characterized, can play an important role as OPH in destroying oxidatively damaged proteins in living cells. PMID:10719179

  7. Reduction-oxidation state and protein degradation in skeletal muscle of fasted and refed rats

    NASA Technical Reports Server (NTRS)

    Fagan, Julie M.; Tischler, Marc E.

    1986-01-01

    Redox state and protein degradation were measured in isolated muscles of fasted (up to 10 d) and refed (up to 4 d) 7- to 14-wk-old rats. Protein degradation in the extensor digitorum longus muscle, but not in the soleus muscle, was greater in the fasted rats than in weight-matched muscle from fed rats. The NAD couple was more oxidized in incubated and fresh extensor digitorum longus muscles and in some incubated soleus muscles of fasted rats than in weight-matched muscle from fed rats. In the extensor digitorum longus muscle of refed or prolonged fasted rats, protein degradation was slower and the NAD couple was more reduced than in the fed state. Therefore, oxidation of the NAD couple was associated with increased muscle breakdown during fasting, whereas reduction of the NAD couple was associated with muscle conservation and deposition.

  8. Regulated spatial organization and sensitivity of cytosolic protein oxidation in Caenorhabditis elegans

    PubMed Central

    Romero-Aristizabal, Catalina; Marks, Debora S.; Fontana, Walter; Apfeld, Javier

    2014-01-01

    Cells adjust their behavior in response to redox events by regulating protein activity through the reversible formation of disulfide bridges between cysteine thiols. However, the spatial and temporal control of these modifications remains poorly understood in multicellular organisms. Here, we measured the protein thiol-disulfide balance in live C. elegans using a genetically-encoded redox sensor and found that it is specific to tissues and patterned spatially within a tissue. Insulin signaling regulates the sensor's oxidation at both of these levels. Unexpectedly, we found that isogenic individuals exhibit large differences in the sensor's thiol-disulfide balance. This variation contrasts with the general view that glutathione acts as the main cellular redox buffer. Indeed, our work suggests that glutathione converts small changes in its oxidation level into large changes in its redox potential. We therefore propose that glutathione facilitates the sensitive control of the thioldisulfide balance of target proteins in response to cellular redox events. PMID:25262602

  9. Highly efficient extraction of cellular nucleic acid associated proteins in vitro with magnetic oxidized carbon nanotubes.

    PubMed

    Zhang, Yi; Hu, Zhengyan; Qin, Hongqiang; Wei, Xiaoluan; Cheng, Kai; Liu, Fangjie; Wu, Ren'an; Zou, Hanfa

    2012-12-01

    Nucleic acid associated proteins (NAaP) play the essential roles in gene regulation and protein expression. The global analysis of cellular NAaP would give a broad insight to understand the interaction between nucleic acids and the associated proteins, such as the important proteinous regulation factors on nucleic acids. Proteomic analysis presents a novel strategy to investigate a group of proteins. However, the large scale analysis of NAaP is yet impossible due to the lack of approaches to harvest target protein groups with a high efficiency. Herein, a simple and efficient method was developed to collect cellular NAaP using magnetic oxidized carbon nanotubes based on the strong interaction between carbon nanotubes and nucleic acids along with corresponding associated proteins. We found that the magnetic oxidized carbon nanotubes demonstrated a nearly 100% extraction efficiency for intracellular nucleic acids from cells in vitro. Importantly, the proteins associated on nucleic acids could be highly efficiently harvested using magnetic oxidized carbon nanotubes due to the binding of NAaP on nucleic acids. 1594 groups of nuclear NAaP and 2595 groups of cellular NAaP were extracted and identified from about 1,000,000 cells, and 803 groups of NAaP were analyzed with only about 10,000 cells, showing a promising performance for the proteomic analysis of NAaP from minute cellular samples. This highly efficient extraction strategy for NAaP is a simple approach to identify cellular nucleic acid associated proteome, and we believed this strategy could be further applied in systems biology to understand the gene expression and regulation. PMID:23121485

  10. Protein oxidative changes in whole and skim milk after ultraviolet or fluorescent light exposure.

    PubMed

    Scheidegger, D; Pecora, R P; Radici, P M; Kivatinitz, S C

    2010-11-01

    We investigated how protein changes occur, at the primary or higher structural levels, when proteins are exposed to UV or fluorescent (FL) light while in the complex matrix, milk. Whole milk (WM) or skim milk (SM) samples were exposed to FL or UV light from 0 to 24h at 4°C. Protein oxidation was evaluated by the formation of protein carbonyls (PC), dityrosine bond (DiTyr), and changes in molecular weight (protein fragmentation and polymerization). Oxidative changes in AA residues were measured by PC. Dityrosine and N'-formylkynurenine (NFK), a carbonylation derivative of Trp, were measured by fluorometry. Protein carbonyls increased as a function of irradiation time for both WM and SM. The initial rate for PC formation by exposure to FL light (0.25 or 0.27 nmol/h for WM and SM, respectively) was slower than that following exposure to UV light (1.95 or 1.20 nmol/h, respectively). The time course of NFK formation resembled that of PC. After 24h of UV exposure, SM had significantly higher levels of NFK than did WM. In contrast, WM samples irradiated with UV had higher levels of DiTyr than did SM samples, indicating different molecular pathways. The formation of intra- or intermolecular DiTyr bonds could be indicative of changes in the tertiary structure or oligomerization of proteins. The existence of NFK suggests the occurrence of protein fragmentation. Thus, proteolysis and oligomerization were analyzed by sodium dodecyl sulfate-PAGE. After 24h of exposing WM to UV or FL light, all the proteins were affected by both types of light, as evidenced by loss of material in most of the bands. Aggregates were produced only by UV irradiation. Hydrolysis by pepsin and enzyme-induced coagulation by rennet were performed to evaluate altered biological properties of the oxidized proteins. No effect on pepsin digestion or rennet coagulation was found in irradiated SM or WM. The oxidative status of proteins in milk and dairy products is of interest to the dairy industry and

  11. A Novel Graphene Oxide-Based Protein Interaction Measurement Using Atomic Force Microscopy.

    PubMed

    Han, Sung-Woong; Morita, Kyohei; Adachi, Taiji

    2015-02-01

    Graphene oxide (GO) is a promising material for biological applications because of its excellent physical/chemical properties such as aqueous processability, amphiphilicity, and surface functionalizability. Here we introduce a new biological application of GO, a novel GO-based technique for probing protein interactions using atomic force microscopy (AFM). GO sheets were intercalated between the protein-modified AFM probe and the polymer substrate in order to reduce the non-specific adhesion force observed during single-molecule force spectroscopy (SMFS). In this study, we used SMFS to probe the interaction of the actin filament and actin-related protein 2/3 complex (Arp2/3), an actin-binding protein. Our results confirm that the GO sheet reduces nonspecific adhesion of the probe to the substrate. Using the GO-based technique, we succeeded in estimating the dissociation constant of the actin filament-binding protein interaction. PMID:26353630

  12. Macromolecular crowding conditions enhance glycation and oxidation of whey proteins in ultrasound-induced Maillard reaction.

    PubMed

    Perusko, Marija; Al-Hanish, Ayah; Cirkovic Velickovic, Tanja; Stanic-Vucinic, Dragana

    2015-06-15

    High intensity ultrasound (HIUS) can promote Maillard reaction (MR). Macromolecular crowding conditions accelerate reactions and stabilise protein structure. The aim of this study was to investigate if combined application of ultrasound and macromolecular crowding can improve efficiency of MR. The presence of crowding agent (polyethylene glycol) significantly increased ultrasound-induced whey protein (WP) glycation by arabinose. An increase in glycation efficiency results only in slight change of WP structure. Macromolecular crowding intensifies oxidative modifications of WP, as well as formation of amyloid-like structures by enhancement of MR. Solubility at different pH, thermal stability and antioxidative capacity of glycated WP were increased, especially in the presence of crowding agent, compared to sonicated nonglycated proteins. The application of HIUS under crowding conditions can be a new approach for enhancement of reactions in general, enabling short processing time and mild conditions, while preserving protein structure and minimising protein aggregation. PMID:25660883

  13. The Role of Metal Regulatory Proteins in Brain Oxidative Stress: A Tutorial

    PubMed Central

    2012-01-01

    The proteins that regulate the metabolism of a metal must also play a role in regulating the redox activity of the metal. Metals are intrinsic to a substantial number of biological processes and the proteins that regulate those activities are also considerable in number. The role these proteins play in a wide range of physiological processes involves them directly and indirectly in a variety of disease processes. Similarly, it may be therapeutically advantageous to pharmacologically alter the activity of these metal containing proteins to influence disease processes. This paper will introduce the reader to a number of important proteins in both metal metabolism and oxidative stress, with an emphasis on the brain. Potential pharmacological targets will be considered. PMID:23304261

  14. Mitochondrial calcium uniporter protein MCU is involved in oxidative stress-induced cell death.

    PubMed

    Liao, Yajin; Hao, Yumin; Chen, Hong; He, Qing; Yuan, Zengqiang; Cheng, Jinbo

    2015-06-01

    Mitochondrial calcium uniporter (MCU) is a conserved Ca(2+) transporter at mitochondrial in eukaryotic cells. However, the role of MCU protein in oxidative stress-induced cell death remains unclear. Here, we showed that ectopically expressed MCU is mitochondrial localized in both HeLa and primary cerebellar granule neurons (CGNs). Knockdown of endogenous MCU decreases mitochondrial Ca(2+) uptake following histamine stimulation and attenuates cell death induced by oxidative stress in both HeLa cells and CGNs. We also found MCU interacts with VDAC1 and mediates VDAC1 overexpression-induced cell death in CGNs. This finding demonstrates that MCU-VDAC1 complex regulates mitochondrial Ca(2+) uptake and oxidative stress-induced apoptosis, which might represent therapeutic targets for oxidative stress related diseases. PMID:25753332

  15. Oxidatively Responsive Chain Extension to Entangle Engineered Protein Hydrogels

    PubMed Central

    Tang, Shengchang; Glassman, Matthew J.; Li, Shuaili; Socrate, Simona; Olsen, Bradley D.

    2014-01-01

    Engineering artificial protein hydrogels for medical applications requires precise control over their mechanical properties, including stiffness, toughness, extensibility and stability in the physiological environment. Here we demonstrate topological entanglement as an effective strategy to robustly increase the mechanical tunability of a transient hydrogel network based on coiled-coil interactions. Chain extension and entanglement are achieved by coupling the cysteine residues near the N- and C- termini, and the resulting chain distribution is found to agree with the Jacobson-Stockmayer theory. By exploiting the reversible nature of the disulfide bonds, the entanglement effect can be switched on and off by redox stimuli. With the presence of entanglements, hydrogels exhibit a 7.2-fold enhanced creep resistance and a suppressed erosion rate by a factor of 5.8, making the gels more mechanically stable in a physiologically relevant open system. While hardly affecting material stiffness (only resulting in a 1.5-fold increase in the plateau modulus), the entanglements remarkably lead to hydrogels with a toughness of 65,000 J m-3 and extensibility to approximately 3,000% engineering strain, which enables the preparation of tough yet soft tissue simulants. This improvement in mechanical properties resembles that from double-network hydrogels, but is achieved with the use of a single associating network and topological entanglement. Therefore, redox-triggered chain entanglement offers an effective approach for constructing mechanically enhanced and responsive injectable hydrogels. PMID:24910474

  16. Ascorbate and Apple Phenolics Affect Protein Oxidation in Emulsion-Type Sausages during Storage and in Vitro Digestion.

    PubMed

    Rysman, Tine; Van Hecke, Thomas; De Smet, Stefaan; Van Royen, Geert

    2016-05-25

    The effect of sodium ascorbate and apple phenolics on the oxidative stability of emulsion-type sausages during storage and digestion was investigated. Emulsion-type sausages containing 0.05% sodium ascorbate or 3% freeze-dried apple pomace were subjected to chilled illuminated storage and subsequent in vitro digestion. Lipid oxidation was assessed as TBARS, and protein oxidation was evaluated as thiol oxidation, total carbonyls, and γ-glutamic and α-amino adipic semialdehyde. Proteolysis was measured after digestion to evaluate protein digestibility. The results suggest the presence of protein-ascorbate and protein-phenol interactions, which may decrease protein digestibility and may interfere with spectrophotometric methods for measuring oxidation. PMID:27133801

  17. Optimization of stabilized leachate treatment using ozone/persulfate in the advanced oxidation process

    SciTech Connect

    Abu Amr, Salem S.; Aziz, Hamidi Abdul; Adlan, Mohd Nordin

    2013-06-15

    Highlights: ► Ozone and persulfate reagent (O{sub 3}/S{sub 2}O{sub 8}{sup 2-}) was used to treat stabilized leachate. ► Central composite design (CCD) with response surface methodology (RSM) was applied. ► Operating variables including ozone and persulfate dosage, pH variance, and reaction time. ► Optimum removal of COD, color, and NH{sub 3}–N was 72%, 96%, and 76%, respectively. ► A good value of ozone consumption (OC) obtained with 0.60 (kg O{sub 3}/kg COD). - Abstract: The objective of this study was to investigate the performance of employing persulfate reagent in the advanced oxidation of ozone to treat stabilized landfill leachate in an ozone reactor. A central composite design (CCD) with response surface methodology (RSM) was applied to evaluate the relationships between operating variables, such as ozone and persulfate dosages, pH, and reaction time, to identify the optimum operating conditions. Quadratic models for the following four responses proved to be significant with very low probabilities (<0.0001): COD, color, NH{sub 3}–N, and ozone consumption (OC). The obtained optimum conditions included a reaction time of 210 min, 30 g/m{sup 3} ozone, 1 g/1 g COD{sub 0}/S{sub 2}O{sub 8}{sup 2-} ratio, and pH 10. The experimental results were corresponded well with predicted models (COD, color, and NH{sub 3}–N removal rates of 72%, 96%, and 76%, respectively, and 0.60 (kg O{sub 3}/kg COD OC). The results obtained in the stabilized leachate treatment were compared with those from other treatment processes, such as ozone only and persulfate S{sub 2}O{sub 8}{sup 2-} only, to evaluate its effectiveness. The combined method (i.e., O{sub 3}/S{sub 2}O{sub 8}{sup 2-}) achieved higher removal efficiencies for COD, color, and NH{sub 3}–N compared with other studied applications. Furthermore, the new method is more efficient than ozone/Fenton in advanced oxidation process in the treatment of the same studied leachate.

  18. General method to identify and enrich vicinal thiol proteins present in intact cells in the oxidized, disulfide state.

    PubMed

    Gitler, C; Zarmi, B; Kalef, E

    1997-10-01

    Some 5% of the soluble proteins of L1210 murine leukemia lymphoblasts contain surface vicinal thiols (Kalef, E., Walfish, P. G., and Gitler, C. (1993) Anal. Biochem. 212, 325-334). Redox dithiol to intraprotein disulfide conversion could regulate the cellular function of these proteins. A general method is presented to identify and enrich vicinal thiol proteins existing in cells in their oxidized, disulfide state. The method is based on the in situ blockage by cell permeable N-ethylmaleimide (NEM) of readily accessible cellular protein sulfhydryls. Following removal of the excess NEM, disulfide-containing proteins were identified by reduction with DTT and specific labeling with N-iodoacetyl-[125I]-3-iodotyrosine. The vicinal thiol proteins formed could also be enriched, prior to labeling with [125I]IAIT, by their selective binding to Sepha-rose-aminohexanoyl-4-aminophenylarsine oxide. Exponentially growing L1210 lymphoblasts contain more than 20 proteins with thiols in the oxidized, disulfide state. The majority derive from vicinal thiol proteins. The fraction oxidized, in some proteins, represents almost the totality of the protein present in the cell. Exposure of lymphoblasts to diamide increases the number and concentration of proteins with intraprotein disulfides. This method allows sensitive direct identification of vicinal thiol proteins that participate in redox regulation and those that are targets to oxidative stress conditions. PMID:9324940

  19. Applicability of fluidized bed reactor in recalcitrant compound degradation through advanced oxidation processes: a review.

    PubMed

    Tisa, Farhana; Abdul Raman, Abdul Aziz; Wan Daud, Wan Mohd Ashri

    2014-12-15

    Treatment of industrial waste water (e.g. textile waste water, phenol waste water, pharmaceutical etc) faces limitation in conventional treatment procedures. Advanced oxidation processes (AOPs) do not suffer from the limits of conventional treatment processes and consequently degrade toxic pollutants more efficiently. Complexity is faced in eradicating the restrictions of AOPs such as sludge formation, toxic intermediates formation and high requirement for oxidants. Increased mass-transfer in AOPs is an alternate solution to this problem. AOPs combined with Fluidized bed reactor (FBR) can be a potential choice compared to fixed bed or moving bed reactor, as AOP catalysts life-span last for only maximum of 5-10 cycles. Hence, FBR-AOPs require lesser operational and maintenance cost by reducing material resources. The time required for AOP can be minimized using FBR and also treatable working volume can be increased. FBR-AOP can process from 1 to 10 L of volume which is 10 times more than simple batch reaction. The mass transfer is higher thus the reaction time is lesser. For having increased mass transfer sludge production can be successfully avoided. The review study suggests that, optimum particle size, catalyst to reactor volume ratio, catalyst diameter and liquid or gas velocity is required for efficient FBR-AOP systems. However, FBR-AOPs are still under lab-scale investigation and for industrial application cost study is needed. Cost of FBR-AOPs highly depends on energy density needed and the mechanism of degradation of the pollutant. The cost of waste water treatment containing azo dyes was found to be US$ 50 to US$ 500 per 1000 gallons where, the cost for treating phenol water was US$ 50 to US$ 800 per 1000 gallons. The analysis for FBR-AOP costs has been found to depend on the targeted pollutant, degradation mechanism (zero order, 1st order and 2nd order) and energy consumptions by the AOPs. PMID:25190594

  20. [Effects of organic pollutants in drinking water on the removal of dimethyl phthalate by advanced oxidation processes].

    PubMed

    Rui, Min; Gao, Nai-yun; Xu, Bin; Li, Fu-sheng; Zhao, Jian-fu; Le, Lin-sheng

    2006-12-01

    Humic acids were used to simulate natural organic compounds in water for the investigation of DMP oxidation by three different AOPs (advanced oxidation processes) of UV-H2O2, O3 and UV-O3. The results showed that pseudo-first-order reaction equation could describe the oxidation of DMP by UV-H2O2 perfectly, which was strongly affected humic acids in water. The relationship between pseudo-first-order reaction rate and TOC value could be expressed as K = 0. 162 0 [TOC]-0.8171. It was also found that humic acids in the water exhibited obvious influence on the oxidation of DMP by UV-O3. However, effect of humic acids on the oxidation of DMP by ozone was not obvious. It was also analyzed that oxidation of DMP was dominated by ozone oxidation both in ozonation process and UV-O3 process; the importance of "OH in the oxidation of DMP was enhanced as the concentration of DMP decreased in UV-O3 process. The degree of impact form humic acids towards different AOPs could be ranked in a decreasing order as UV-H2O3, UV-O3, 03. PMID:17304847

  1. Nitric oxide-based protein modification: formation and site-specificity of protein S-nitrosylation: Could protein S-nitrosylation be the unifying oxidative modification to explain the cellular signaling activity of superoxide and hydrogen peroxide?

    PubMed

    Clement, Marie-Veronique

    2014-10-01

    Accumulating evidence indicates that reactive oxygen species (ROS) and reactive nitrogen species (RNS) function as signaling molecules in physiological settings by acting as second messengers in response to external stimuli such as growth factors, cytokines and hormones. The nature of the ROS involved in cell signaling as well as the underlying mechanisms by which ROS modify protein function to influence cellular processes have been unfolding over the past decade. ROS and RNS influence various cellular processes by altering the function of critical proteins via reversible oxidation of "reactive cysteine" residues. Protein S-nitrosylation is a mechanism of nitric oxide-based signaling, however, while the presence of NO is sufficient and may be a prerequisite for the formation of cysteine-SNO, we reasoned that if protein-SNO formation is a critical cystein modification for redox driven signal transduction, an increase in intracellular ROS such as H2O2 and O2(-), shown to be independently involved in cell signaling, might both promote the formation of protein-SNO. In this respect, the present study shows that an increase in protein-SNO was detected not only upon an increase in the intracellular level of nitric oxide (NO), but also following exposure to low concentration of exogenous hydrogen peroxide (H2O2) or upon inhibition of the Cu/Zn superoxide dismutase that results in increased intracellular O2(-). PMID:26461291

  2. Inhibition of Lipid Oxidation in Oil-in-Water Emulsions by Interface-Adsorbed Myofibrillar Protein.

    PubMed

    Yang, Jiayi; Xiong, Youling L

    2015-10-14

    This study investigated the role of interfacial myofibrillar protein (MFP) in the oxidative stabilization of meat emulsions. Emulsions with 10% oil were prepared using either 2% (w/v) Tween 20 or 0.25, 0.5, and 1% (w/v) MFP and then subjected to hydroxyl radical oxidation at 4 °C for 0, 2, and 24 h. MFP was more readily oxidized (intrinsic fluorescence quenching, sulfur losses, and carbonyl formation) than oil [conjugated dienes and 2-thiobarbituric acid-reactive substances (TBARS)]. However, oxidized MFP in the continuous phase stimulated lipid oxidation after 24 h, sharply contrasting with interface-adsorbed MFP that inhibited TBARS formation nearly 90% (p < 0.05). Interfacial MFP from 2 h oxidized samples exhibited greater losses of fluorescence and more extensive polymerization of myosin (detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis) than MFP present in the continuous phase. Results indicated that, due to the physical localization, interface-adsorbed MFP in general and myosin in particular provided accentuated protection of emulsions against oxidation. PMID:26414649

  3. Application of mass spectrometry for the detection of glycation and oxidation products in milk proteins.

    PubMed

    Meltretter, Jasmin; Pischetsrieder, Monika

    2008-04-01

    Protein mass spectometry techniques, such as electrospray ionization mass spectrometry or matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), are effective methods to screen for protein modifications derived from the Maillard reaction. The analysis of the intact proteins reveals the major modification, most commonly the Amadori product, whereas partial enzymatic hydrolysis prior to mass spectrometry additionally allows the detection of minor adducts. Therefore, a mass spectrometric method was developed for the analysis of whey protein modifications occurring during heat treatment. The two main whey proteins, alpha-lactalbumin and beta-lactoglobulin, were incubated with lactose in a milk model and modifications were recorded using MALDI-TOF-MS. The analysis of the intact proteins revealed protein species with 0-4 lactulosyl residues. Partial enzymatic hydrolysis with endoproteinase AspN prior to mass spectrometric analysis enabled the detection of further modifications and their localization in the amino acid sequence. Detected modifications were lactulosyllysine, N epsilon-(carboxymethyl)lysine, lysine aldehyde, methionine sulfoxide, cyclization of N-terminal glutamic acid to a pyrrolidone, and oxidation of cysteine or tryptophan. Protein modifications in heated milk and commercially available dairy products can be analyzed after the separation of the milk proteins using one-dimensional SDS-PAGE. PMID:18448807

  4. Purification and properties of a protein linked to the soluble hydrogenase of hydrogen-oxidizing bacteria.

    PubMed Central

    Kärst, U; Suetin, S; Friedrich, C G

    1987-01-01

    In Alcaligenes eutrophus, the formation of the hydrogenases and of five new peptides is subject to the hydrogenase control system. Of these, the B peptide was purified to homogeneity. This protein (Mr, 37,500) was composed of two identical subunits (Mr, 18,800). Antibodies against the B protein were used for its quantification by rocket immunoelectrophoresis. About 4% of the total protein consisted of the B protein; its molar ratio to the NAD-linked hydrogenase was about 4:1. The B protein appeared to be associated with the NAD-linked hydrogenase, as shown by gel filtration analysis with Sephadex G-200. The B protein was not detected in cells that had not expressed the hydrogenase proteins or that lacked the genetic information of the hydrogen-oxidizing character; it was also not detected in Tn5 insertional mutants that were unable to form soluble hydrogenase antigens. Immunochemical analysis of other species and genera than A. eutrophus revealed that only strains able to form a NAD-linked hydrogenase also formed B-protein antigens. The B protein is not required for the catalytic activity of soluble hydrogenase in vitro; its function is at present unknown. Images PMID:3553156

  5. Personalized disease-specific protein corona influences the therapeutic impact of graphene oxide

    NASA Astrophysics Data System (ADS)

    Hajipour, Mohammad Javad; Raheb, Jamshid; Akhavan, Omid; Arjmand, Sareh; Mashinchian, Omid; Rahman, Masoud; Abdolahad, Mohammad; Serpooshan, Vahid; Laurent, Sophie; Mahmoudi, Morteza

    2015-05-01

    The hard corona, the protein shell that is strongly attached to the surface of nano-objects in biological fluids, is recognized as the first layer that interacts with biological objects (e.g., cells and tissues). The decoration of the hard corona (i.e., the type, amount, and conformation of the attached proteins) can define the biological fate of the nanomaterial. Recent developments have revealed that corona decoration strongly depends on the type of disease in human patients from which the plasma is obtained as a protein source for corona formation (referred to as the `personalized protein corona'). In this study, we demonstrate that graphene oxide (GO) sheets can trigger different biological responses in the presence of coronas obtained from various types of diseases. GO sheets were incubated with plasma from human subjects with different diseases/conditions, including hypofibrinogenemia, blood cancer, thalassemia major, thalassemia minor, rheumatism, fauvism, hypercholesterolemia, diabetes, and pregnancy. Identical sheets coated with varying protein corona decorations exhibited significantly different cellular toxicity, apoptosis, and uptake, reactive oxygen species production, lipid peroxidation and nitrogen oxide levels. The results of this report will help researchers design efficient and safe, patient-specific nano biomaterials in a disease type-specific manner for clinical and biological applications.The hard corona, the protein shell that is strongly attached to the surface of nano-objects in biological fluids, is recognized as the first layer that interacts with biological objects (e.g., cells and tissues). The decoration of the hard corona (i.e., the type, amount, and conformation of the attached proteins) can define the biological fate of the nanomaterial. Recent developments have revealed that corona decoration strongly depends on the type of disease in human patients from which the plasma is obtained as a protein source for corona formation (referred

  6. Development of nanomaterial-enabled advanced oxidation techniques for treatment of organic micropollutants

    NASA Astrophysics Data System (ADS)

    Oulton, Rebekah Lynn

    Increasing demand for limited fresh water resources necessitates that alternative water sources be developed. Nonpotable reuse of treated wastewater represents one such alternative. However, the ubiquitous presence of organic micropollutants such as pharmaceuticals and personal care products (PPCPs) in wastewater effluents limits use of this resource. Numerous investigations have examined PPCP fate during wastewater treatment, focusing on their removal during conventional and advanced treatment processes. Analysis of influent and effluent data from published studies reveals that at best 1-log10 concentration unit of PPCP removal can generally be achieved with conventional treatment. In contrast, plants employing advanced treatment methods, particularly ozonation and/or membranes, remove most PPCPs often to levels below analytical detection limits. However, membrane treatment is cost prohibitive for many facilities, and ozone treatment can be very selective. Ozone-recalcitrant compounds require the use of Advanced Oxidation Processes (AOPs), which utilize highly reactive hydroxyl radicals (*OH) to target resistant pollutants. Due to cost and energy use concerns associated with current AOPs, alternatives such as catalytic ozonation are under investigation. Catalytic ozonation uses substrates such as activated carbon to promote *OH formation during ozonation. Here, we show that multi-walled carbon nanotubes (MWCNTs) represent another viable substrate, promoting *OH formation during ozonation to levels exceeding activated carbon and equivalent to conventional ozone-based AOPs. Via a series of batch reactions, we observ a strong correlation between *OH formation and MWCNT surface oxygen concentrations. Results suggest that deprotonated carboxyl groups on the CNT surface are integral to their reactivity toward ozone and corresponding *OH formation. From a practical standpoint, we show that industrial grade MWCNTs exhibit similar *OH production as their research

  7. Oxidative stress-induced assembly of PML nuclear bodies controls sumoylation of partner proteins.

    PubMed

    Sahin, Umut; Ferhi, Omar; Jeanne, Marion; Benhenda, Shirine; Berthier, Caroline; Jollivet, Florence; Niwa-Kawakita, Michiko; Faklaris, Orestis; Setterblad, Niclas; de Thé, Hugues; Lallemand-Breitenbach, Valérie

    2014-03-17

    The promyelocytic leukemia (PML) protein organizes PML nuclear bodies (NBs), which are stress-responsive domains where many partner proteins accumulate. Here, we clarify the basis for NB formation and identify stress-induced partner sumoylation as the primary NB function. NB nucleation does not rely primarily on intermolecular interactions between the PML SUMO-interacting motif (SIM) and SUMO, but instead results from oxidation-mediated PML multimerization. Oxidized PML spherical meshes recruit UBC9, which enhances PML sumoylation, allow partner recruitment through SIM interactions, and ultimately enhance partner sumoylation. Intermolecular SUMO-SIM interactions then enforce partner sequestration within the NB inner core. Accordingly, oxidative stress enhances NB formation and global sumoylation in vivo. Some NB-associated sumoylated partners also become polyubiquitinated by RNF4, precipitating their proteasomal degradation. As several partners are protein-modifying enzymes, NBs could act as sensors that facilitate and confer oxidative stress sensitivity not only to sumoylation but also to other post-translational modifications, thereby explaining alterations of stress response upon PML or NB loss. PMID:24637324

  8. Flow-dependent regulation of endothelial nitric oxide synthase: role of protein kinases

    NASA Technical Reports Server (NTRS)

    Boo, Yong Chool; Jo, Hanjoong

    2003-01-01

    Vascular endothelial cells are directly and continuously exposed to fluid shear stress generated by blood flow. Shear stress regulates endothelial structure and function by controlling expression of mechanosensitive genes and production of vasoactive factors such as nitric oxide (NO). Though it is well known that shear stress stimulates NO production from endothelial nitric oxide synthase (eNOS), the underlying molecular mechanisms remain unclear and controversial. Shear-induced production of NO involves Ca2+/calmodulin-independent mechanisms, including phosphorylation of eNOS at several sites and its interaction with other proteins, including caveolin and heat shock protein-90. There have been conflicting results as to which protein kinases-protein kinase A, protein kinase B (Akt), other Ser/Thr protein kinases, or tyrosine kinases-are responsible for shear-dependent eNOS regulation. The functional significance of each phosphorylation site is still unclear. We have attempted to summarize the current status of understanding in shear-dependent eNOS regulation.

  9. Hold or Fold – Proteins in Advanced Heart Failure and Myocardial Recovery

    PubMed Central

    Mahr, Claudius; Gundry, Rebekah L.

    2015-01-01

    Advanced heart failure describes the subset of heart failure patients refractory to conventional medical therapy. For some advanced heart failure patients, the use of mechanical circulatory support provides an intermediary “bridge” step for transplant eligible patients or an alternative therapy for transplant ineligible patients. Over the past 20 years, clinical observations have revealed that approximately 1% of patients with mechanical circulatory support undergo significant reverse remodeling to the point where the device can be explanted. Unfortunately, it is unclear why some patients experience durable, sustained myocardial remission, while others re-develop heart failure (i.e. which hearts “hold” and which hearts “fold”). In this review, we outline unmet clinical needs related to treating patients with mechanical circulatory support, provide an overview of protein dynamics in the reverse remodeling process, and propose specific areas where we expect mass spectrometry and proteomic analyses will have significant impact on our understanding of disease progression, molecular mechanisms of recovery, and provide new markers with prognostic value that can positively impact patient care. Complimentary perspectives are provided with the goal of making this important topic accessible and relevant to both a clinical and basic science audience, as the intersection of these disciplines is required to advance the field. PMID:25331159

  10. High Temperature Oxidation of Silicon Carbide and Advanced Iron-Based Alloys in Steam-Hydrogen Environments

    SciTech Connect

    Terrani, Kurt A; Keiser, James R; Brady, Michael P; Cheng, Ting; Silva, G W Chinthaka M; Pint, Bruce A; Snead, Lance Lewis

    2012-01-01

    A side by side comparison of the oxidation behavior of zirconium alloys with SiC materials and advanced iron-based alloys is provided. Oxidation tests were conducted in steam and steam-hydrogen environments at 800-1350 C and 0.34-2MPa for durations up to 48 hours. Monolithic SiC specimens as well as SiC/SiC composites were examined during the study where the material recession mechanism appeared to be governed by silica layer volatilization at the surface for CVD SiC. A wide set of austenitic and ferritic steels were also examined where a critical Cr content (>20 wt.%) was shown to be necessary to achieve oxidation resistance at high temperatures. SiC materials and alumina-forming ferritic steels exhibited slowest oxidation kinetics; roughly two orders of magnitude lower than zirconium alloys.

  11. Short-Term Oxidation Studies on Nicrofer- 6025HT in Air at Elevated Temperatures for Advanced Coal Based Power Plants

    SciTech Connect

    Joshi, Vineet V.; Meier, Alan; Darsell, Jens T.; Nachimuthu, Ponnusamy; Bowden, Mark E.; Weil, K. Scott

    2013-04-01

    Several advanced air separation unit (ASU) designs being considered for use in coal gasification rely on the use of solid state mixed ionic and electronic conductors. Nicrofer-6025HT, a nickel-based alloy, has been identified as a potential manifold material to transport the hot gases into the ASUs. In the current study, isothermal oxidation tests were conducted on Nicrofer-6025HT in the temperature range of 700–900 °C for up to 24 h. The evolution of oxide scale was evaluated using SEM, XRD, and XPS. The composite surface oxide layer that formed consisted of an outer chromia-rich scale and an inner alumina scale. For the longer times at the higher temperatures evaluated, a NiCr2O4 spinel phase was located at the interface between the alumina and chromia. Based on the experimental results a four-step oxidation model was proposed.

  12. Myocardial Oxidative Metabolism and Protein Synthesis during Mechanical Circulatory Support by Extracorporeal Membrane Oxygenation

    SciTech Connect

    Priddy, MD, Colleen M.; Kajimoto, Masaki; Ledee, Dolena; Bouchard, Bertrand; Isern, Nancy G.; Olson, Aaron; Des Rosiers, Christine; Portman, Michael A.

    2013-02-01

    Extracorporeal membrane oxygenation (ECMO) provides mechanical circulatory support essential for survival in infants and children with acute cardiac decompensation. However, ECMO also causes metabolic disturbances, which contribute to total body wasting and protein loss. Cardiac stunning can also occur which prevents ECMO weaning, and contributes to high mortality. The heart may specifically undergo metabolic impairments, which influence functional recovery. We tested the hypothesis that ECMO alters oxidative. We focused on the amino acid leucine, and integration with myocardial protein synthesis. We used a translational immature swine model in which we assessed in heart (i) the fractional contribution of leucine (FcLeucine) and pyruvate (FCpyruvate) to mitochondrial acetyl-CoA formation by nuclear magnetic resonance and (ii) global protein fractional synthesis (FSR) by gas chromatography-mass spectrometry. Immature mixed breed Yorkshire male piglets (n = 22) were divided into four groups based on loading status (8 hours of normal circulation or ECMO) and intracoronary infusion [13C6,15N]-L-leucine (3.7 mM) alone or with [2-13C]-pyruvate (7.4 mM). ECMO decreased pulse pressure and correspondingly lowered myocardial oxygen consumption (~ 40%, n = 5), indicating decreased overall mitochondrial oxidative metabolism. However, FcLeucine was maintained and myocardial protein FSR was marginally increased. Pyruvate addition decreased tissue leucine enrichment, FcLeucine, and Fc for endogenous substrates as well as protein FSR. Conclusion: The heart under ECMO shows reduced oxidative metabolism of substrates, including amino acids, while maintaining (i) metabolic flexibility indicated by ability to respond to pyruvate, and (ii) a normal or increased capacity for global protein synthesis, suggesting an improved protein balance.

  13. Myocardial oxidative metabolism and protein synthesis during mechanical circulatory support by extracorporeal membrane oxygenation

    PubMed Central

    Priddy, Colleen M. O′Kelly; Kajimoto, Masaki; Ledee, Dolena R.; Bouchard, Bertrand; Isern, Nancy; Olson, Aaron K.; Rosiers, Christine Des

    2013-01-01

    Extracorporeal membrane oxygenation (ECMO) provides essential mechanical circulatory support necessary for survival in infants and children with acute cardiac decompensation. However, ECMO also causes metabolic disturbances, which contribute to total body wasting and protein loss. Cardiac stunning can also occur, which prevents ECMO weaning, and contributes to high mortality. The heart may specifically undergo metabolic impairments, which influence functional recovery. We tested the hypothesis that ECMO alters oxidative metabolism and protein synthesis. We focused on the amino acid leucine and integration with myocardial protein synthesis. We used a translational immature swine model in which we assessed in heart 1) the fractional contribution of leucine (FcLeucine) and pyruvate to mitochondrial acetyl-CoA formation by nuclear magnetic resonance and 2) global protein fractional synthesis (FSR) by gas chromatography-mass spectrometry. Immature mixed breed Yorkshire male piglets (n = 22) were divided into four groups based on loading status (8 h of normal circulation or ECMO) and intracoronary infusion [13C6,15N]-L-leucine (3.7 mM) alone or with [2-13C]-pyruvate (7.4 mM). ECMO decreased pulse pressure and correspondingly lowered myocardial oxygen consumption (∼40%, n = 5), indicating decreased overall mitochondrial oxidative metabolism. However, FcLeucine was maintained and myocardial protein FSR was marginally increased. Pyruvate addition decreased tissue leucine enrichment, FcLeucine, and Fc for endogenous substrates as well as protein FSR. The heart under ECMO shows reduced oxidative metabolism of substrates, including amino acids, while maintaining 1) metabolic flexibility indicated by ability to respond to pyruvate and 2) a normal or increased capacity for global protein synthesis. PMID:23203964

  14. Lipid and protein oxidation in hepatic homogenates and cell membranes exposed to bile acids.

    PubMed

    Fuentes-Broto, Lorena; Martínez-Ballarín, Enrique; Miana-Mena, Javier; Berzosa, Cesar; Piedrafita, Eduardo; Cebrián, Igor; Reiter, Russel J; García, Joaquín J

    2009-01-01

    Cholestasis occurs in a variety of hepatic diseases and causes damage due to accumulation of bile acids in the liver. The aim was to investigate the effect of several bile acids, i.e. chenodeoxycholic, taurochenodeoxycholic, deoxycholic, taurodeoxycholic, ursodeoxycholic, lithocholic and taurolithocholic (TLC), in inducing oxidative damage. Hepatic tissue of male Sprague-Dawley rats was incubated with or without 1 mM of each bile acid, with or without 0.1 mM FeCl(3) and 0.1 mM ascorbic acid for the purpose of generating free radicals. Several bile acids increased lipid and protein oxidation, with TLC being the most pro-oxidative (657% and 175% in homogenates and 350% and 311% in membranes, respectively). TLC also enhanced iron-induced oxidative stress to lipids (21% in homogenates and 29% in membranes) and to proteins (74% in membranes). This enhancement was dose- and time-dependent and was reduced by melatonin. These results suggest that bile acids differentially mediate hepatic oxidative stress and may be involved in the physiopathology of cholestasis. PMID:19669996

  15. Simulation for supporting scale-up of a fluidized bed reactor for advanced water oxidation.

    PubMed

    Tisa, Farhana; Raman, Abdul Aziz Abdul; Daud, Wan Mohd Ashri Wan

    2014-01-01

    Simulation of fluidized bed reactor (FBR) was accomplished for treating wastewater using Fenton reaction, which is an advanced oxidation process (AOP). The simulation was performed to determine characteristics of FBR performance, concentration profile of the contaminants, and various prominent hydrodynamic properties (e.g., Reynolds number, velocity, and pressure) in the reactor. Simulation was implemented for 2.8 L working volume using hydrodynamic correlations, continuous equation, and simplified kinetic information for phenols degradation as a model. The simulation shows that, by using Fe(3+) and Fe(2+) mixtures as catalyst, TOC degradation up to 45% was achieved for contaminant range of 40-90 mg/L within 60 min. The concentration profiles and hydrodynamic characteristics were also generated. A subsequent scale-up study was also conducted using similitude method. The analysis shows that up to 10 L working volume, the models developed are applicable. The study proves that, using appropriate modeling and simulation, data can be predicted for designing and operating FBR for wastewater treatment. PMID:25309949

  16. Response surface methodology for ozonation of trifluralin using advanced oxidation processes in an airlift photoreactor

    NASA Astrophysics Data System (ADS)

    Behin, J.; Farhadian, N.

    2016-06-01

    Degradation of trifluralin, as a wide used pesticide, was investigated by advance oxidation process comprising O3/UV/H2O2 in a concentric tube airlift photoreactor. Main and interactive effects of three independent factors including pH (5-9), superficial gas velocity (0.05-0.15 cm/s) and time (20-60 min) on the removal efficiency were assessed using central composite face-centered design and response surface method (RSM). The RSM allows to solve multivariable equations and to estimate simultaneously the relative importance of several contributing parameters even in the presence of complex interaction. Airlift photoreactor imposed a synergistic effect combining good mixing intensity merit with high ozone transfer rate. Mixing in the airlift photoreactor enhanced the UV light usage efficiency and its availability. Complete degradation of trifluralin was achieved under optimum conditions of pH 9 and superficial gas velocity 0.15 cm/s after 60 min of reaction time. Under these conditions, degradation of trifluralin was performed in a bubble column photoreactor of similar volume and a lower efficiency was observed.

  17. Formation of disinfection by-products in the ultraviolet/chlorine advanced oxidation process.

    PubMed

    Wang, Ding; Bolton, James R; Andrews, Susan A; Hofmann, Ron

    2015-06-15

    Disinfection by-product (DBP) formation may be a concern when applying ultraviolet light and free chlorine (UV/chlorine) as an advanced oxidation process (AOP) for drinking water treatment, due to typically large chlorine doses (e.g. 5-10 mg L(-1) as free chlorine). A potential mitigating factor is the low chlorine contact times for this AOP treatment (e.g. seconds). Full-scale and pilot-scale test results showed minimal trihalomethane (THM) and haloacetic acid (HAA) formation during UV/chlorine treatment, while dichloroacetonitrile (DCAN) and bromochloroacetonitrile (BCAN) were produced rapidly. Adsorbable organic halide (AOX) formation was significant when applying the UV/chlorine process in water that had not been previously chlorinated, while little additional formation was observed in prechlorinated water. Chlorine photolysis led to chlorate and bromate formation, equivalent to approximately 2-17% and 0.01-0.05% of the photolyzed chlorine, respectively. No perchlorate or chlorite formation was observed. During simulated secondary disinfection of AOP-treated water, DBP formation potential for THMs, HAAs, HANs, and AOX was observed to increase approximately to the same extent as was observed for pretreatment using the more common AOP of UV combined with hydrogen peroxide (UV/H2O2). PMID:25747363

  18. Reaction kinetics of selected micropollutants in ozonation and advanced oxidation processes.

    PubMed

    Jin, Xiaohui; Peldszus, Sigrid; Huck, Peter M

    2012-12-01

    Second-order reaction rate constants of micropollutants with ozone (k(O3)) and hydroxyl radicals (k(OH)) are essential for evaluating their removal efficiencies from water during ozonation and advanced oxidation processes. Kinetic data are unavailable for many of the emerging micropollutants. Twenty-four micropollutants with very diverse structures and applications including endocrine disrupting compounds, pharmaceuticals, and personal care products were selected, and their k(O3) and k(OH) values were determined using bench-scale reactors (at pH 7 and T = 20 °C). Reactions with molecular ozone are highly selective as indicated by their k(O3) values ranging from 10(-2)-10(7) M(-1) s(-1). The general trend of ozone reactivity can be explained by micropollutant structures in conjunction with the electrophilic nature of ozone reactions. All of the studied compounds are highly reactive with hydroxyl radicals as shown by their high k(OH) values (10(8)-10(10) M(-1) s(-1)) even though they are structurally very diverse. For compounds with a low reactivity toward ozone, hydroxyl radical based treatment such as O(3)/H(2)O(2) or UV/H(2)O(2) is a viable alternative. This study contributed to filling the data gap pertaining kinetic data of organic micropollutants while confirming results reported in the literature where available. PMID:23079129

  19. Recent advances in superparamagnetic iron oxide nanoparticles (SPIONs) for in vitro and in vivo cancer nanotheranostics.

    PubMed

    Kandasamy, Ganeshlenin; Maity, Dipak

    2015-12-30

    Recently superparamagnetic iron oxide nanoparticles (SPIONs) have been extensively used in cancer therapy and diagnosis (theranostics) via magnetic targeting, magnetic resonance imaging, etc. due to their remarkable magnetic properties, chemical stability, and biocompatibility. However, the magnetic properties of SPIONs are influenced by various physicochemical and synthesis parameters. So, this review mainly focuses on the influence of spin canting effects, introduced by the variations in size, shape, and organic/inorganic surface coatings, on the magnetic properties of SPIONs. This review also describes the several predominant chemical synthesis procedures and role of the synthesis parameters for monitoring the size, shape, crystallinity and composition of the SPIONs. Moreover, this review discusses about the latest developments of the inorganic materials and organic polymers for encapsulation of the SPIONs. Finally, the most recent advancements of the SPIONs and their nanopackages in combination with other imaging/therapeutic agents have been comprehensively discussed for their effective usage as in vitro and in vivo theranostic agents in cancer treatments. PMID:26520409

  20. LiNiFe-based layered structure oxide and composite for advanced single layer fuel cells

    NASA Astrophysics Data System (ADS)

    Zhu, Bin; Fan, Liangdong; Deng, Hui; He, Yunjune; Afzal, Muhammad; Dong, Wenjing; Yaqub, Azra; Janjua, Naveed K.

    2016-06-01

    A layered structure metal oxide, LiNi0.1Fe0.90O2-δ (LNF), is explored for the advanced single layer fuel cells (SLFCs). The temperature dependent impedance profiles and concentration cells (hydrogen concentration, oxygen concentration, and H2/air atmospheres) tests prove LNF to be an intrinsically electronic conductor in air while mixed electronic and proton conductor in H2/air environment. SLFCs constructed by pure LNF materials show significant short circuiting reflected by a low device OCV and power output (175 mW cm-2 at 500 °C) due to high intrinsic electronic conduction. The power output is improved up to 640 and 760 mW cm-2, respectively at 500 and 550 °C by compositing LNF with ion conducting material, e.g., samarium doped ceria (SDC), to balance the electronic and ionic conductivity; both reached at 0.1 S cm-1 level. Such an SLFC gives super-performance and simplicity over the conventional 3-layer (anode, electrolyte and cathode) FCs, suggesting strong scientific and commercial impacts.

  1. Degradation of atrazine using solar driven fenton-like advanced oxidation processes.

    PubMed

    Bandala, Erick R; Domínguez, Zair; Rivas, Fernanda; Gelover, Silvia

    2007-01-01

    Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) was degraded using cobalt-peroximonosulfate (Co/PMS) advanced oxidation process (AOP). Three Co concentrations (0.00, 0.25 and 0.50 mM) and five peroximonosulfate (PMS) concentrations (0, 5, 8, 16 and 32 mM) were tested. Maximum degradation reached was 88% using dark Co/PMS in 126 minutes when 0.25 mM of cobalt and 32 mM of PMS were used. Complete atrazine degradation was achieved when the samples were irradiated by the sun under the same experimental conditions described. Tests for identification of intermediate products allowed identification and quantification of deethylatrazine in both dark and radiated conditions. Kinetic data for both processes was calculated fitting a pseudo-first order reaction rate approach to the experimental data. Having kinetic parameters enabled comparison between both conditions. It was found that the kinetic approach describes data behavior appropriately (R2 > or = 0.95). Pseudo-kinetic constants determined for both Co/PMS processes, show k value of 10(-4) for Co/PMS and a k value of 10(-3) for Co/PMS/ultraviolet (UV). This means, that, with the same Co/PMS concentrations, UV light increases the reaction rate by around one order of magnitude than performing the reaction under dark conditions. PMID:17162564

  2. Simulation for Supporting Scale-Up of a Fluidized Bed Reactor for Advanced Water Oxidation

    PubMed Central

    Abdul Raman, Abdul Aziz; Daud, Wan Mohd Ashri Wan

    2014-01-01

    Simulation of fluidized bed reactor (FBR) was accomplished for treating wastewater using Fenton reaction, which is an advanced oxidation process (AOP). The simulation was performed to determine characteristics of FBR performance, concentration profile of the contaminants, and various prominent hydrodynamic properties (e.g., Reynolds number, velocity, and pressure) in the reactor. Simulation was implemented for 2.8 L working volume using hydrodynamic correlations, continuous equation, and simplified kinetic information for phenols degradation as a model. The simulation shows that, by using Fe3+ and Fe2+ mixtures as catalyst, TOC degradation up to 45% was achieved for contaminant range of 40–90 mg/L within 60 min. The concentration profiles and hydrodynamic characteristics were also generated. A subsequent scale-up study was also conducted using similitude method. The analysis shows that up to 10 L working volume, the models developed are applicable. The study proves that, using appropriate modeling and simulation, data can be predicted for designing and operating FBR for wastewater treatment. PMID:25309949

  3. Conventional and advanced oxidation processes used in disinfection of treated urban wastewater.

    PubMed

    Rodríguez-Chueca, J; Ormad, M P; Mosteo, R; Sarasa, J; Ovelleiro, J L

    2015-03-01

    The purpose of the current study is to compare the inactivation of Escherichia coli in wastewater effluents using conventional treatments (chlorination) and advanced oxidation processes (AOPs) such as UV irradiation, hydrogen peroxide (H2O2)/solar irradiation, and photo-Fenton processes. In addition, an analysis of the operational costs of each treatment is carried out taking into account the optimal dosages of chemicals used. Total inactivation of bacteria (7.5 log) was achieved by means of chlorination and UV irradiation. However, bacterial regrowth was observed 6 hours after the completion of UV treatment, obtaining a disinfection value around 3 to 4 log. On the other hand, the combination H2O2/solar irradiation achieved a maximum inactivation of E. coli of 3.30 ± 0.35 log. The photo-Fenton reaction achieved a level of inactivation of 4.87 ± 0.10 log. The order of disinfection, taking into account the reagent/cost ratio of each treatment, is as follows: chlorination > UV irradiation > photo-Fenton > H2O2/sunlight irradiation. PMID:25842540

  4. Pilot-scale treatment of olive oil mill wastewater by physicochemical and advanced oxidation processes.

    PubMed

    Kiliç, M Yalili; Yonar, T; Kestioğlu, K

    2013-01-01

    The pilot-scale treatability of olive oil mill wastewater (OOMW) by physicochemical methods, ultrafiltration and advanced oxidation processes (AOPs) was investigated. Physicochemical methods (acid cracking, oil separation and coagulation-flocculation) showed high efficiency of chemical oxygen demand (COD) (85%), oil and grease (O&G) (> 97%), suspended solids (SS) (> 99%) and phenol (92%) removal from the OOMW. Ultrafiltration followed by physicochemical methods is effective in reducing the SS, O&G. The final permeate quality is found to be excellent with over 90% improvements in the COD and phenol parameters. AOPs (ozonation at a high pH, O3/UV, H2O2/UV, and O3/H2O2/UV) increased the removal efficiency and the O3/H2O2/UV combination among other AOPs studied in this paper was found to give the best results (> 99% removal for COD, > 99% removal for phenol and > 99% removal for total organic carbon). Pilot-scale treatment plant has been continuously operated on site for three years (3 months olive oil production campaign period of each year). The capital and operating costs of the applied treatment alternatives were also determined at the end of these seasons. The results obtained in this study have been patented for 7 years by the Turkish Patent Institute. PMID:24191487

  5. Using advanced oxidation treatment for biofilm inactivation by varying water vapor content in air plasma

    NASA Astrophysics Data System (ADS)

    Ryota, Suganuma; Koichi, Yasuoka

    2015-09-01

    Biofilms are caused by environmental degradation in food factories and medical facilities. The inactivation of biofilms involves making them react with chemicals including chlorine, hydrogen peroxide, and ozone, although inactivation using chemicals has a potential problem because of the hazardous properties of the residual substance and hydrogen peroxide, which have slow reaction velocity. We successfully performed an advanced oxidation process (AOP) using air plasma. Hydrogen peroxide and ozone, which were used for the formation of OH radicals in our experiment, were generated by varying the amount of water vapor supplied to the plasma. By varying the content of the water included in the air, the main product was changed from air plasma. When we increased the water content in the air, hydrogen peroxide was produced, while ozone peroxide was produced when we decreased the water content in the air. By varying the amount of water vapor, we realized a 99.9% reduction in the amount of bacteria in the biofilm when we discharged humidified air only. This work was supported by JSPS KAKENHI Grant Number 25630104.

  6. Imbalance of heterologous protein folding and disulfide bond formation rates yields runaway oxidative stress

    PubMed Central

    2012-01-01

    Background The protein secretory pathway must process a wide assortment of native proteins for eukaryotic cells to function. As well, recombinant protein secretion is used extensively to produce many biologics and industrial enzymes. Therefore, secretory pathway dysfunction can be highly detrimental to the cell and can drastically inhibit product titers in biochemical production. Because the secretory pathway is a highly-integrated, multi-organelle system, dysfunction can happen at many levels and dissecting the root cause can be challenging. In this study, we apply a systems biology approach to analyze secretory pathway dysfunctions resulting from heterologous production of a small protein (insulin precursor) or a larger protein (α-amylase). Results HAC1-dependent and independent dysfunctions and cellular responses were apparent across multiple datasets. In particular, processes involving (a) degradation of protein/recycling amino acids, (b) overall transcription/translation repression, and (c) oxidative stress were broadly associated with secretory stress. Conclusions Apparent runaway oxidative stress due to radical production observed here and elsewhere can be explained by a futile cycle of disulfide formation and breaking that consumes reduced glutathione and produces reactive oxygen species. The futile cycle is dominating when protein folding rates are low relative to disulfide bond formation rates. While not strictly conclusive with the present data, this insight does provide a molecular interpretation to an, until now, largely empirical understanding of optimizing heterologous protein secretion. This molecular insight has direct implications on engineering a broad range of recombinant proteins for secretion and provides potential hypotheses for the root causes of several secretory-associated diseases. PMID:22380681

  7. Cigarette smoke-induced protein oxidation and proteolysis is exclusively caused by its tar phase: prevention by vitamin C.

    PubMed

    Panda, K; Chattopadhyay, R; Chattopadhyay, D; Chatterjee, I B

    2001-08-01

    We have reported before that whole phase cigarette smoke (CS) contains stable oxidants that cause oxidative damage and increased proteolysis of proteins [Free Radic. Biol. Med. 27 (1999) 1064]. Here, we demonstrate that these oxidants are exclusively present in the tar phase of the CS and not its gas phase and can almost wholly account for the observed whole phase CS-induced oxidation of human plasma proteins as well as extensive oxidative proteolysis of guinea pig lung and heart microsomal proteins in vitro. The mechanism of the tar phase CS-induced proteolysis of microsomal proteins involves two-steps: (i) initial oxidation of the proteins by oxidants present in the tar extract followed by (ii) rapid proteolytic degradation of the oxidized proteins by proteases present in the microsomes. Like the whole phase CS, the oxidative damage of proteins caused by the tar phase CS, as evidenced by the formation of protein carbonyl and bityrosine as well as loss of tryptophan residues and thiol groups, is also almost completely prevented by ascorbic acid and only partially by glutathione. Other antioxidants, including superoxide dismutase, catalase, vitamin E, beta-carotene and mannitol are ineffective. This again leads us to suggest that adequate intake of vitamin C may help smokers to evade the CS-induced degenerative diseases associated with oxidative damage. The revelation of the acute toxicity of the tar phase with respect to CS-induced oxidative damage also urges the necessity of trapping it more effectively by suitable cigarette filters to reduce the health damage caused to smokers. PMID:11514102

  8. Effect of pomegranate peel extract on lipid and protein oxidation in beef meatballs during refrigerated storage.

    PubMed

    Turgut, Sebahattin Serhat; Soyer, Ayla; Işıkçı, Fatma

    2016-06-01

    Antioxidant effect of pomegranate peel extract (PE) to retard lipid and protein oxidation was investigated in meatballs during refrigerated storage at 4±1°C. Concentrated lyophilised water extract of pomegranate peel was incorporated into freshly minced beef meat at 0.5% and 1% concentrations and compared with 0.01% butylated hydroxytoluene (BHT) as a reference and control (without any antioxidant). PE showed high phenolic content and antioxidant activity. In PE added samples, thiobarbituric acid reactive substances (TBARS) value, peroxide formation, loss of sulfhydryl groups and formation of protein carbonyls were lower than control (P<0.01) after 8 days of storage. Sensory evaluation with respect to colour and rancid odour revealed that PE incorporation in meatballs prolonged the refrigerated storage up to 8 days. Addition of both 0.5 and 1% PE in meatballs reduced lipid and protein oxidation and improved sensory scores. These results indicated that PE was effective on retarding lipid and protein oxidation. PMID:26878610

  9. Physical and oxidative stability of fish oil-in-water emulsions stabilized with fish protein hydrolysates.

    PubMed

    García-Moreno, Pedro J; Guadix, Antonio; Guadix, Emilia M; Jacobsen, Charlotte

    2016-07-15

    The emulsifying and antioxidant properties of fish protein hydrolysates (FPH) for the physical and oxidative stabilization of 5% (by weight) fish oil-in-water emulsions were investigated. Muscle proteins from sardine (Sardina pilchardus) and small-spotted catshark (Scyliorhinus canicula) were hydrolyzed to degrees of hydrolysis (DH) of 3-4-5-6% with subtilisin. Sardine hydrolysates with low DH, 3% and 4%, presented the most effective peptides to physically stabilize emulsions with smaller droplet size. This implied more protein adsorbed at the interface to act as physical barrier against prooxidants. This fact might also be responsible for the higher oxidative stability of these emulsions, as shown by their lowest peroxide value and concentration of volatiles such as 1-penten-3-one and 1-penten-3-ol. Among the hydrolysates prepared from small-spotted catshark only the hydrolysate with DH 3% yielded a physically stable emulsion with low concentration of unsaturated aldehydes. These results show the potential of FPH as alternative protein emulsifiers for the production of oxidatively stable fish oil-in-water emulsions. PMID:26948597

  10. An oxidized tryptophan facilitates copper binding in Methylococcus capsulatus-secreted protein MopE.

    PubMed

    Helland, Ronny; Fjellbirkeland, Anne; Karlsen, Odd Andre; Ve, Thomas; Lillehaug, Johan R; Jensen, Harald B

    2008-05-16

    Proteins can coordinate metal ions with endogenous nitrogen and oxygen ligands through backbone amino and carbonyl groups, but the amino acid side chains coordinating metals do not include tryptophan. Here we show for the first time the involvement of the tryptophan metabolite kynurenine in a protein metal-binding site. The crystal structure to 1.35 angstroms of MopE* from the methane-oxidizing Methylococcus capsulatus (Bath) provided detailed information about its structure and mononuclear copper-binding site. MopE* contains a novel protein fold of which only one-third of the structure displays similarities to other known folds. The geometry around the copper ion is distorted tetrahedral with one oxygen ligand from a water molecule, two histidine imidazoles (His-132 and His-203), and at the fourth distorted tetrahedral position, the N1 atom of the kynurenine, an oxidation product of Trp-130. Trp-130 was not oxidized to kynurenine in MopE* heterologously expressed in Escherichia coli, nor did this protein bind copper. Our findings indicate that the modification of tryptophan to kynurenine and its involvement in copper binding is an innate property of M. capsulatus MopE*. PMID:18348978

  11. HCV core protein uses multiple mechanisms to induce oxidative stress in human hepatoma Huh7 cells.

    PubMed

    Ivanov, Alexander V; Smirnova, Olga A; Petrushanko, Irina Y; Ivanova, Olga N; Karpenko, Inna L; Alekseeva, Ekaterina; Sominskaya, Irina; Makarov, Alexander A; Bartosch, Birke; Kochetkov, Sergey N; Isaguliants, Maria G

    2015-06-01

    Hepatitis C virus (HCV) infection is accompanied by the induction of oxidative stress, mediated by several virus proteins, the most prominent being the nucleocapsid protein (HCV core). Here, using the truncated forms of HCV core, we have delineated several mechanisms by which it induces the oxidative stress. The N-terminal 36 amino acids of HCV core induced TGF\\(\\upbeta\\)1-dependent expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidases 1 and 4, both of which independently contributed to the production of reactive oxygen species (ROS). The same fragment also induced the expression of cyclo-oxygenase 2, which, however, made no input into ROS production. Amino acids 37-191 of HCV core up-regulated the transcription of a ROS generating enzyme cytochrome P450 2E1. Furthermore, the same fragment induced the expression of endoplasmic reticulum oxidoreductin 1\\(\\upalpha\\). The latter triggered efflux of Ca2+ from ER to mitochondria via mitochondrial Ca2+ uniporter, leading to generation of superoxide anions, and possibly also H2O2. Suppression of any of these pathways in cells expressing the full-length core protein led to a partial inhibition of ROS production. Thus, HCV core causes oxidative stress via several independent pathways, each mediated by a distinct region of the protein. PMID:26035647

  12. Identifying initial molecular targets of PDT: protein and lipid oxidation products

    NASA Astrophysics Data System (ADS)

    Oleinick, Nancy L.; Kim, Junhwan; Rodriguez, Myriam E.; Xue, Liang-yan; Kenney, Malcolm E.; Anderson, Vernon E.

    2009-06-01

    Photodynamic Therapy (PDT) generates singlet oxygen (1O2) which oxidizes biomolecules in the immediate vicinity of its formation. The phthalocyanine photosensitizer Pc 4 localizes to mitochondria and endoplasmic reticulum, and the primary targets of Pc 4-PDT are expected to be lipids and proteins of those membranes. The initial damage then causes apoptosis in cancer cells via the release of cytochrome c (Cyt-c) from mitochondria into the cytosol, followed by the activation of caspases. That damage also triggers the induction of autophagy, an attempt by the cells to eliminate damaged organelles, or when damage is too extensive, to promote cell death. Cyt-c is bound to the cytosolic side of the mitochondrial inner membrane through association with cardiolipin (CL), a phospholipid containing four unsaturated fatty acids and thus easily oxidized by 1O2 or by other oxidizing agents. Increasing evidence suggests that oxidation of CL loosens its association with Cyt-c, and that the peroxidase activity of Cyt-c can oxidize CL. In earlier studies of Cyt-c in homogeneous medium by MALDI-TOF-MS and LC-ESI-MS, we showed that 1O2 generated by Pc 4-PDT oxidized histidine, methionine, tryptophan, and unexpectedly phenylalanine but not tyrosine. Most of the oxidation products were known to be formed by other oxidizing agents, such as hydroxyl radical, superoxide radical anion, and peroxynitrite. However, two products of histidine were unique to 1O2 and may be useful for reporting the action of 1O2 in cells and tissues. These products, as well as CL oxidation products, have now been identified in liposomes and mitochondria after Pc 4-PDT. In mitochondria, the PDT dose-dependent oxidations can be related to specific changes in mitochondrial function, Bcl-2 photodamage, and Cyt-c release. Thus, the role of PDT-generated 1O2 in oxidizing Cyt-c and CL and the interplay between protein and lipid targets may be highly relevant to understanding one mechanism for cell killing by PDT.

  13. Proteins and protein complexes involved in the biochemical reactions of anaerobic ammonium-oxidizing bacteria.

    PubMed

    de Almeida, Naomi M; Maalcke, Wouter J; Keltjens, Jan T; Jetten, Mike S M; Kartal, Boran

    2011-01-01

    It has been less than two decades since anammox (anaerobic ammonium oxidation) coupled to nitrite reduction has been discovered. Already, this process has been recognized as an important sink for fixed nitrogen in the natural environment and has been implemented as a cost-effective ammonium removal technology. Still, little is known about the molecular mechanism of this remarkable reaction. In this mini review, we present an insight into how ammonium and nitrite are combined to form dinitrogen gas. PMID:21265793

  14. Enigma, a mitochondrial protein affecting lifespan and oxidative stress response in Drosophila

    PubMed Central

    Mourikis, Philippos; Hurlbut, Gregory D.; Artavanis-Tsakonas, Spyros

    2006-01-01

    Deregulation of energy metabolism by external interventions or mutations in metabolic genes can extend lifespan in a wide range of species. We describe mutations in Drosophila melanogaster that confer resistance to oxidative stress and display a longevity phenotype. These phenotypes are associated with molecular lesions in a hitherto uncharacterized gene we named Enigma. We show that Enigma encodes a mitochondrial protein with homology to enzymes of the β-oxidation of fatty acids and that mutations in this locus affect lipid homeostasis. Our analysis provides further support to the notion that lipid metabolism may play a central role in metazoan lifespan regulation. PMID:16434470

  15. Bisecting GlcNAc modification stabilizes BACE1 protein under oxidative stress conditions.

    PubMed

    Kizuka, Yasuhiko; Nakano, Miyako; Kitazume, Shinobu; Saito, Takashi; Saido, Takaomi C; Taniguchi, Naoyuki

    2016-01-01

    β-Site amyloid precursor protein-cleaving enzyme-1 (BACE1) is a protease essential for amyloid-β (Aβ) production in Alzheimer's disease (AD). BACE1 protein is known to be up-regulated by oxidative stress-inducing stimuli but the mechanism for this up-regulation still needs to be clarified. We have recently found that BACE1 is modified with bisecting N-acetylglucosamine (GlcNAc) by N-acetylglucosaminyltransferase-III (GnT-III, encoded by the Mgat3 gene) and that GnT-III deficiency reduces Aβ-plaque formation in the brain by accelerating lysosomal degradation of BACE1. Therefore, we hypothesized that bisecting GlcNAc would stabilize BACE1 protein on oxidative stress. In the present study, we first show that Aβ deposition in the mouse brain induces oxidative stress, together with an increase in levels of BACE1 and bisecting GlcNAc. Furthermore, prooxidant treatment induces expression of BACE1 protein in wild-type mouse embryonic fibroblasts (MEFs), whereas it reduces BACE1 protein in GnT-III (Mgat3) knock-out MEFs by accelerating lysosomal degradation of BACE1. We purified BACE1 from Neuro2A cells and performed LC/ESI/MS analysis for BACE1-derived glycopeptides and mapped bisecting GlcNAc-modified sites on BACE1. Point mutations at two N-glycosylation sites (Asn(153) and Asn(223)) abolish the bisecting GlcNAc modification on BACE1. These mutations almost cancelled the enhanced BACE1 degradation seen in Mgat3(-/-) MEFs, indicating that bisecting GlcNAc on BACE1 indeed regulates its degradation. Finally, we show that traumatic brain injury-induced BACE1 up-regulation is significantly suppressed in the Mgat3(-/-) brain. These results highlight the role of bisecting GlcNAc in oxidative stress-induced BACE1 expression and offer a novel glycan-targeted strategy for suppressing Aβ generation. PMID:26467158

  16. Advances in urinary protein biomarkers for urogenital and non-urogenital pathologies

    PubMed Central

    Pedroza-Díaz, Johanna

    2015-01-01

    The discovery of protein biomarkers that reflect the biological state of the body is of vital importance to disease management. Urine is an ideal source of biomarkers that provides a non-invasive approach to diagnosis, prognosis and prediction of diseases. Consequently, the study of the human urinary proteome has increased dramatically over the last 10 years, with many studies being published. This review focuses on urinary protein biomarkers that have shown potential, in initial studies, for diseases affecting the urogenital tract, specifically chronic kidney disease and prostate cancer, as well as other non-urogenital pathologies such as breast cancer, diabetes, atherosclerosis and osteoarthritis. PubMed was searched for peer-reviewed literature on the subject, published in the last 10 years. The keywords used were “urine, biomarker, protein, and/or prostate cancer/breast cancer/chronic kidney disease/diabetes/atherosclerosis/osteoarthritis”. Original studies on the subject, as well as a small number of reviews, were analysed including the strengths and weaknesses, and we summarized the performance of biomarkers that demonstrated potential. One of the biggest challenges found is that biomarkers are often shared by several pathologies so are not specific to one disease. Therefore, the trend is shifting towards implementing a panel of biomarkers, which may increase specificity. Although there have been many advances in urinary proteomics, these have not resulted in similar advancements in clinical practice due to high costs and the lack of large data sets. In order to translate these potential biomarkers to clinical practice, vigorous validation is needed, with input from industry or large collaborative studies. PMID:25672464

  17. Validation of membrane protein topology models by oxidative labeling and mass spectrometry.

    PubMed

    Pan, Yan; Ruan, Xiang; Valvano, Miguel A; Konermann, Lars

    2012-05-01

    Computer-assisted topology predictions are widely used to build low-resolution structural models of integral membrane proteins (IMPs). Experimental validation of these models by traditional methods is labor intensive and requires modifications that might alter the IMP native conformation. This work employs oxidative labeling coupled with mass spectrometry (MS) as a validation tool for computer-generated topology models. ·OH exposure introduces oxidative modifications in solvent-accessible regions, whereas buried segments (e.g., transmembrane helices) are non-oxidizable. The Escherichia coli protein WaaL (O-antigen ligase) is predicted to have 12 transmembrane helices and a large extramembrane domain (Pérez et al., Mol. Microbiol. 2008, 70, 1424). Tryptic digestion and LC-MS/MS were used to map the oxidative labeling behavior of WaaL. Met and Cys exhibit high intrinsic reactivities with ·OH, making them sensitive probes for solvent accessibility assays. Overall, the oxidation pattern of these residues is consistent with the originally proposed WaaL topology. One residue (M151), however, undergoes partial oxidation despite being predicted to reside within a transmembrane helix. Using an improved computer algorithm, a slightly modified topology model was generated that places M151 closer to the membrane interface. On the basis of the labeling data, it is concluded that the refined model more accurately reflects the actual topology of WaaL. We propose that the combination of oxidative labeling and MS represents a useful strategy for assessing the accuracy of IMP topology predictions, supplementing data obtained in traditional biochemical assays. In the future, it might be possible to incorporate oxidative labeling data directly as constraints in topology prediction algorithms. PMID:22410873

  18. Validation of Membrane Protein Topology Models by Oxidative Labeling and Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Pan, Yan; Ruan, Xiang; Valvano, Miguel A.; Konermann, Lars

    2012-05-01

    Computer-assisted topology predictions are widely used to build low-resolution structural models of integral membrane proteins (IMPs). Experimental validation of these models by traditional methods is labor intensive and requires modifications that might alter the IMP native conformation. This work employs oxidative labeling coupled with mass spectrometry (MS) as a validation tool for computer-generated topology models. ṡOH exposure introduces oxidative modifications in solvent-accessible regions, whereas buried segments (e.g., transmembrane helices) are non-oxidizable. The Escherichia coli protein WaaL (O-antigen ligase) is predicted to have 12 transmembrane helices and a large extramembrane domain (Pérez et al., Mol. Microbiol. 2008, 70, 1424). Tryptic digestion and LC-MS/MS were used to map the oxidative labeling behavior of WaaL. Met and Cys exhibit high intrinsic reactivities with ṡOH, making them sensitive probes for solvent accessibility assays. Overall, the oxidation pattern of these residues is consistent with the originally proposed WaaL topology. One residue (M151), however, undergoes partial oxidation despite being predicted to reside within a transmembrane helix. Using an improved computer algorithm, a slightly modified topology model was generated that places M151 closer to the membrane interface. On the basis of the labeling data, it is concluded that the refined model more accurately reflects the actual topology of WaaL. We propose that the combination of oxidative labeling and MS represents a useful strategy for assessing the accuracy of IMP topology predictions, supplementing data obtained in traditional biochemical assays. In the future, it might be possible to incorporate oxidative labeling data directly as constraints in topology prediction algorithms.

  19. Hepatitis C Virus Attenuates Mitochondrial Lipid β-Oxidation by Downregulating Mitochondrial Trifunctional-Protein Expression

    PubMed Central

    Munakata, Tsubasa; Kohara, Michinori; Siddiqui, Aleem; Peers, Chris

    2015-01-01

    ABSTRACT The course of hepatitis C virus (HCV) infection and disease progression involves alterations in lipid metabolism, leading to symptoms such as hypocholesterolemia and steatosis. Steatosis can be induced by multiple mechanisms, including increases in lipid biosynthesis and uptake, impaired lipoprotein secretion, and/or attenuation of lipid β-oxidation. However, little is known about the effects of HCV on lipid β-oxidation. A previous proteomics study revealed that HCV interacted with both the α- and β-subunits of the mitochondrial trifunctional protein (MTP), an enzyme complex which catalyzes the last 3 steps of mitochondrial lipid β-oxidation for cellular energy production. Here we show that in HCV-infected Huh7.5 cells, lipid β-oxidation was significantly attenuated. Consistently with this, MTP protein and mRNA levels were suppressed by HCV infection. A loss-of-function study showed that MTP depletion rendered cells less responsive to alpha interferon (IFN-α) treatment by impairing IFN-stimulated gene expression. These aspects of host-virus interaction explain how HCV alters host energy homeostasis and how it may also contribute to the establishment of persistent infection in the liver. IMPORTANCE HCV infection triggers metabolic alterations, which lead to significant disease outcomes, such as fatty liver (steatosis). This study revealed that HCV impairs mitochondrial lipid β-oxidation, which results in low lipid combustion. On the other hand, the HCV-induced defects in metabolic status played an important role in the control of the type I interferon system. Under the conditions of impaired lipid β-oxidation, host cells were less responsive to the ability of exogenously added IFN-α to suppress HCV replication. This suggests that interference with lipid β-oxidation may assist the virus in the establishment of a long-term, persistent infection. Further understanding of this aspect of virus-host interaction may lead to improvements in the current

  20. Identification of enzymes and regulatory proteins in Escherichia coli that are oxidized under nitrogen, carbon, or phosphate starvation

    PubMed Central

    Noda, Yasuko; Berlett, Barbara S.; Stadtman, Earl R.; Aponte, Angel; Morgan, Meghan; Shen, Rong-Fong

    2007-01-01

    Using proteomic technologies, we identified 62 proteins that are oxidized to carbonyl derivatives during growth of Escherichia coli under nitrogen starvation (NS), carbon starvation (CS), and phosphate starvation (PS) conditions. The carbonylated proteins were converted to 2,4-dinitrophenylhydrazone derivatives and these were identified using Western blotting and mass spectrometry by searching E. coli proteins in the Swiss-Prot and/or NCBI databases. Fourteen of the oxidized proteins were formed under both NS and CS conditions, and only three proteins were specifically oxidized under PS conditions. Interestingly, the carbonyl content of proteins in crude extracts of cells harvested after 48 h of stationary growth under NS and CS was significantly lower than that observed at mid-log and end-log phases of growth. In contrast, the carbonyl content of proteins in extracts of cells grown under PS conditions was fairly constant during comparable periods of growth. PMID:18003895

  1. Combined advanced oxidation and biodegradation of industrial effluents from the production of stilbene-based fluorescent whitening agents.

    PubMed

    Hörsch, Philip; Speck, Andreas; Frimmel, Fritz H

    2003-06-01

    Three different industrial wastewaters from the production of stilbene-based fluorescent whitening agents were investigated with regard to the applicability of advanced oxidation processes combined with biodegradation. Oxidation processes included the application of ozone, hydrogen peroxide, UV-radiation and Fenton's reagent (Fe(2+)/H(2)O(2)). Characterization of the combined chemical-biological treatment was done by sum parameters and HPLC analysis. In addition, toxicity was determined using the luminescence inhibition test. Results showed that processes producing OH-radicals without the need of UV-irradiation proved to be suited for the oxidation of all three wastewaters. H(2)O(2)/UV processes were ineffective due to the high inner filter effect of the effluents. Comparing the combined oxidative-biological process with biological treatment, the applied pre-oxidation steps did not always lead to a significant improvement of the biological degradation. In one case, an inverted treatment starting with biodegradation followed by oxidation turned out to be the preferable procedure. After oxidation with ozone or ozone combined with UV-irradiation, an increase in toxicity was partly observed indicating the formation of toxic intermediate products. In some cases samples had to be diluted before the biodegradation step to achieve a better biodegradability. PMID:12753853

  2. Review: Advances in Vascular Tissue Engineering Using Protein-Based Biomaterials

    PubMed Central

    Stegemann, Jan P.; Kaszuba, Stephanie N.; Rowe, Shaneen L.

    2008-01-01

    The clinical need for improved blood vessel substitutes, especially in small-diameter applications, drives the field of vascular tissue engineering. The blood vessel has a well-characterized structure and function, but it is a complex tissue, and it has proven difficult to create engineered tissues that are suitable for widespread clinical use. This review is focused on approaches to vascular tissue engineering that use proteins as the primary matrix or “scaffold” material for creating fully biological blood vessel replacements. In particular, this review covers four main approaches to vascular tissue engineering: 1) cell-populated protein hydrogels, 2) cross-linked protein scaffolds, 3) decellularized native tissues, and 4) self-assembled scaffolds. Recent advances in each of these areas are discussed, along with advantages of and drawbacks to these approaches. The first fully biological engineered blood vessels have entered clinical trials, but important challenges remain before engineered vascular tissues will have a wide clinical effect. Cell sourcing and recapitulating the biological and mechanical function of the native blood vessel continue to be important outstanding hurdles. In addition, the path to commercialization for such tissues must be better defined. Continued progress in several complementary approaches to vascular tissue engineering is necessary before blood vessel substitutes can achieve their full potential in improving patient care. PMID:17961004

  3. The CSB chromatin remodeler and CTCF architectural protein cooperate in response to oxidative stress

    PubMed Central

    Lake, Robert J.; Boetefuer, Erica L.; Won, Kyoung-Jae; Fan, Hua-Ying

    2016-01-01

    Cockayne syndrome is a premature aging disease associated with numerous developmental and neurological abnormalities, and elevated levels of reactive oxygen species have been found in cells derived from Cockayne syndrome patients. The majority of Cockayne syndrome cases contain mutations in the ATP-dependent chromatin remodeler CSB; however, how CSB protects cells from oxidative stress remains largely unclear. Here, we demonstrate that oxidative stress alters the genomic occupancy of the CSB protein and increases CSB occupancy at promoters. Additionally, we found that the long-range chromatin-structure regulator CTCF plays a pivotal role in regulating sites of genomic CSB occupancy upon oxidative stress. We show that CSB directly interacts with CTCF in vitro and that oxidative stress enhances the CSB-CTCF interaction in cells. Reciprocally, we demonstrate that CSB facilitates CTCF-DNA interactions in vitro and regulates CTCF-chromatin interactions in oxidatively stressed cells. Together, our results indicate that CSB and CTCF can regulate each other's chromatin association, thereby modulating chromatin structure and coordinating gene expression in response to oxidative stress. PMID:26578602

  4. Protein Kinase A Governs Oxidative Phosphorylation Kinetics and Oxidant Emitting Potential at Complex I

    PubMed Central

    Lark, Daniel S.; Reese, Lauren R.; Ryan, Terence E.; Torres, Maria J.; Smith, Cody D.; Lin, Chien-Te; Neufer, P. Darrell

    2015-01-01

    The mitochondrial electron transport system (ETS) is responsible for setting and maintaining both the energy and redox charges throughout the cell. Reversible phosphorylation of mitochondrial proteins, particularly via the soluble adenylyl cyclase (sAC)/cyclic AMP (cAMP)/Protein kinase A (PKA) axis, has recently been revealed as a potential mechanism regulating the ETS. However, the governance of cAMP/PKA signaling and its implications on ETS function are incompletely understood. In contrast to prior reports using exogenous bicarbonate, we provide evidence that endogenous CO2 produced by increased tricarboxylic acid (TCA) cycle flux is insufficient to increase mitochondrial cAMP levels, and that exogenous addition of membrane permeant 8Br-cAMP does not enhance mitochondrial respiratory capacity. We also report important non-specific effects of commonly used inhibitors of sAC which preclude their use in studies of mitochondrial function. In isolated liver mitochondria, inhibition of PKA reduced complex I-, but not complex II-supported respiratory capacity. In permeabilized myofibers, inhibition of PKA lowered both the Km and Vmax for complex I-supported respiration as well as succinate-supported H2O2 emitting potential. In summary, the data provided here improve our understanding of how mitochondrial cAMP production is regulated, illustrate a need for better tools to examine the impact of sAC activity on mitochondrial biology, and suggest that cAMP/PKA signaling contributes to the governance of electron flow through complex I of the ETS. PMID:26635618

  5. Plasma Proteins Modified by Advanced Glycation End Products (AGEs) Reveal Site-specific Susceptibilities to Glycemic Control in Patients with Type 2 Diabetes.

    PubMed

    Greifenhagen, Uta; Frolov, Andrej; Blüher, Matthias; Hoffmann, Ralf

    2016-04-29

    Protein glycation refers to the reversible reaction between aldoses (or ketoses) and amino groups yielding relatively stable Amadori (or Heyns) products. Consecutive oxidative cleavage reactions of these products or the reaction of amino groups with other reactive substances (e.g. α-dicarbonyls) yield advanced glycation end products (AGEs) that can alter the structures and functions of proteins. AGEs have been identified in all organisms, and their contents appear to rise with some diseases, such as diabetes and obesity. Here, we report a pilot study using highly sensitive and specific proteomics approach to identify and quantify AGE modification sites in plasma proteins by reversed phase HPLC mass spectrometry in tryptic plasma digests. In total, 19 AGE modification sites corresponding to 11 proteins were identified in patients with type 2 diabetes mellitus under poor glycemic control. The modification degrees of 15 modification sites did not differ among cohorts of normoglycemic lean or obese and type 2 diabetes mellitus patients under good and poor glycemic control. The contents of two amide-AGEs in human serum albumin and apolipoprotein A-II were significantly higher in patients with poor glycemic control, although the plasma levels of both proteins were similar among all plasma samples. These two modification sites might be useful to predict long term, AGE-related complications in diabetic patients, such as impaired vision, increased arterial stiffness, or decreased kidney function. PMID:26933035

  6. Multivalency in the Inhibition of Oxidative Protein Folding by Arsenic(III) Species

    PubMed Central

    2015-01-01

    The renewed use of arsenicals as chemotherapeutics has rekindled interest in the biochemistry of As(III) species. In this work, simple bis- and tris-arsenical derivatives were synthesized with the aim of exploiting the chelate effect in the inhibition of thiol-disulfide oxidoreductases (here, Quiescin sulfhydryl oxidase, QSOX, and protein disulfide isomerase, PDI) that utilize two or more CxxC motifs in the catalysis of oxidative protein folding. Coupling 4-aminophenylarsenoxide (APAO) to acid chloride or anhydride derivatives yielded two bis-arsenical prototypes, BA-1 and BA-2, and a tris-arsenical, TA-1. Unlike the monoarsenical, APAO, these new reagents proved to be strong inhibitors of oxidative protein folding in the presence of a realistic intracellular concentration of competing monothiol (here, 5 mM reduced glutathione, GSH). However, this inhibition does not reflect direct inactivation of QSOX or PDI, but avid binding of MVAs to the reduced unfolded protein substrates themselves. Titrations of reduced riboflavin-binding protein with MVAs show that all 18 protein −SH groups can be captured by these arsenicals. With reduced RNase, addition of substoichiometric levels of MVAs is accompanied by the formation of Congo Red- and Thioflavin T-positive fibrillar aggregates. Even with Kd values of ∼50 nM, MVAs are ineffective inhibitors of PDI in the presence of millimolar levels of competing GSH. These results underscore the difficulties of designing effective and specific arsenical inhibitors for folded enzymes and proteins. Some of the cellular effects of arsenicals likely reflect their propensity to associate very tightly and nonspecifically to conformationally mobile cysteine-rich regions of proteins, thereby interfering with folding and/or function. PMID:25506675

  7. Membrane Protein Structure Determination Using Crystallography and Lipidic Mesophases - Recent Advances and Successes

    PubMed Central

    Caffrey, Martin; Li, Dianfan; Dukkipati, Abhiram

    2012-01-01

    activity of membrane proteins reconstituted into the bilayer of the cubic phase as a prelude to crystallogenesis. Glass crystallization plates have been built that provide unparalleled optical quality and sensitivity to nascent crystals. Lipid and precipitant screens have been designed for a more rational approach to crystallogenesis such that the method can now be applied to an even wider variety of membrane protein types. In this Current Topics article, these assorted advances are outlined along with a summary of the membrane proteins that have yielded to the method. The prospects for and the challenges that must be overcome to further develop the method are described. PMID:22783824

  8. Killing Me Softly: Connotations to Unfolded Protein Response and Oxidative Stress in Alzheimer's Disease

    PubMed Central

    Pająk, Beata; Kania, Elżbieta; Orzechowski, Arkadiusz

    2016-01-01

    This review is focused on the possible causes of mitochondrial dysfunction in AD, underlying molecular mechanisms of this malfunction, possible causes and known consequences of APP, Aβ, and hyperphosphorylated tau presence in mitochondria, and the contribution of altered lipid metabolism (nonsterol isoprenoids) to pathological processes leading to increased formation and accumulation of the aforementioned hallmarks of AD. Abnormal protein folding and unfolded protein response seem to be the outcomes of impaired glycosylation due to metabolic disturbances in geranylgeraniol intermediary metabolism. The origin and consecutive fate of APP, Aβ, and tau are emphasized on intracellular trafficking apparently influenced by inaccurate posttranslational modifications. We hypothesize that incorrect intracellular processing of APP determines protein translocation to mitochondria in AD. Similarly, without obvious reasons, the passage of Aβ and tau to mitochondria is observed. APP targeted to mitochondria blocks the activity of protein translocase complex resulting in poor import of proteins central to oxidative phosphorylation. Besides, APP, Aβ, and neurofibrillary tangles of tau directly or indirectly impair mitochondrial biochemistry and bioenergetics, with concomitant generation of oxidative/nitrosative stress. Limited protective mechanisms are inadequate to prevent the free radical-mediated lesions. Finally, neuronal loss is observed in AD-affected brains typically by pathologic apoptosis. PMID:26881014

  9. Borna disease virus P protein inhibits nitric oxide synthase gene expression in astrocytes

    SciTech Connect

    Peng Guiqing; Zhang Fengmin; Zhang Qi; Wu Kailang; Zhu Fan; Wu Jianguo

    2007-09-30

    Borna disease virus (BDV) is one of the potential infectious agents involved in the development of central nervous system (CNS) diseases. Neurons and astrocytes are the main targets of BDV infection, but little is known about the roles of BDV infection in the biological effects of astrocytes. Here we reported that BDV inhibits the activation of inducible nitric oxide synthase (iNOS) in murine astrocytes induced by bacterial LPS and PMA. To determine which protein of BDV is responsible for the regulation of iNOS expression, we co-transfected murine astrocytes with reporter plasmid iNOS-luciferase and plasmid expressing individual BDV proteins. Results from analyses of reporter activities revealed that only the phosphoprotein (P) of BDV had an inhibitory effect on the activation of iNOS. In addition, P protein inhibits nitric oxide production through regulating iNOS expression. We also reported that the nuclear factor kappa B (NF-{kappa}B) binding element, AP-1 recognition site, and interferon-stimulated response element (ISRE) on the iNOS promoter were involved in the repression of iNOS gene expression regulated by the P protein. Functional analysis indicated that sequences from amino acids 134 to 174 of the P protein are necessary for the regulation of iNOS. These data suggested that BDV may suppress signal transduction pathways, which resulted in the inhibition of iNOS activation in astrocytes.

  10. The dual function of flavodiiron proteins: oxygen and/or nitric oxide reductases.

    PubMed

    Romão, Célia V; Vicente, João B; Borges, Patrícia T; Frazão, Carlos; Teixeira, Miguel

    2016-03-01

    Flavodiiron proteins have emerged in the last two decades as a newly discovered family of oxygen and/or nitric oxide reductases widespread in the three life domains, and present in both aerobic and anaerobic organisms. Herein we present the main features of these fascinating enzymes, with a particular emphasis on the metal sites, as more appropriate for this special issue in memory of the exceptional bioinorganic scientist R. J. P. Williams who pioneered the notion of (metal) element availability-driven evolution. We also compare the flavodiiron proteins with the other oxygen and nitric