Horseradish peroxidase compound I as a tool to investigate reactive protein-cysteine residues: from quantification to kinetics

Proteins containing reactive cysteine residues (protein-Cys) are receiving increased attention as mediators of hydrogen peroxide signaling. These proteins are mainly identified by mining the thiol proteomes of oxidized protein-Cys in cells and tissues. However, it is difficult to determine if oxidation occurs through a direct reaction with hydrogen peroxide or by thiol-disulfide exchange reactions. Kinetic studies with purified proteins provide invaluable information about the reactivity of protein-Cys residues with hydrogen peroxide. Previously, we showed that the characteristic UV-Vis spectrum of horseradish peroxidase compound I, produced from the oxidation of horseradish peroxidase by hydrogen peroxide, is a simple, reliable, and useful tool to determine the second-order rate constant of the reaction of reactive protein-Cys with hydrogen peroxide and peroxynitrite. Here, the method is fully described and extended to quantify reactive protein-Cys residues and micromolar concentrations of hydrogen peroxide. Members of the peroxiredoxin family were selected for the demonstration and validation of this methodology. In particular, we determined the pK(a) of the peroxidatic thiol of rPrx6 (5.2) and the second-order rate constant of its reactions with hydrogen peroxide ((3.4 +/- 0.2) x 10(7) M(-1) s(-1)) and peroxynitrite ((3.7 +/- 0.4) x 10(5) M(-1) s(-1)) at pH 7.4 and 25 degrees C. (C) 2011 Elsevier Inc. All rights reserved.

Chemical modification of a nanocrystalline TiO(2) film for efficient electric connection of glucose oxidase

A novel biosensor for glucose was prepared by adsorption of 1,1`-bis(4-carboxybenzyl)-4,4`-bipyridinium di-bromide compound (H(2)BpybcBr(2)) onto the surface of a nanocrystalline TiO(2) film deposited onto FTO glasses, which was used as a platform to assemble the enzyme glucose oxidase to the electrode surface. The H(2)BpybcBr(2)/TiO(2)/FTO modified electrode was characterized by scanning electron microscopy, X-ray fluorescence image, cyclic voltammograms and spectroelectrochemical measurements. The immobilization of GOD on functionalized TiO(2) film led to stable amperometric biosensing for glucose with a linear range from 153 mu mol L(-1) to 1.30 mmol L(-1) and a detection limit of 51 mu mol L(-1). The apparent Michaelis-Menten constant (K(m)) was estimated to be 3.76 mmol L(-1), which suggested a high enzyme-substrate affinity. The maximum electrode sensitivity was 1.25 mu A mmol L(-1). The study proved that the combination of viologen mediators with TiO(2) film retains the electrocatalytic activity of the enzyme, and also enhances the electron transfer process, and hence regenerating the enzyme in the reaction with glucose. (C) 2010 Elsevier Inc. All rights reserved.

Immobilization of Catalysts of Biological Interest on Porous Oxidized Silicon Surfaces

The present paper deals with the immobilization of redox mediators and proteins onto protected porous silicon surfaces to obtain their direct electrochemical reactions and to retain their bioactivities. This paper shows that MP-11 and viologens are able to establish chemical bonds with 3-aminopropyltriethoxylsilane-modified porous silicon surface. The functionalization of the surfaces have been fully characterized by energy dispersive X-ray analysis (EDX) and X-ray photoelectron spectroscopy (XPS) to examine the immobilization of these mediators onto the solid surface. Amperometric and open circuit potential measurements have shown the direct electron transfer between glucose oxidase and the electrode in the presence of the viologen mediator covalently linked to the 3-aminopropyltriethoxylsilane (APTES)-modified porous silicon surfaces.

Triphenylmethane dyes, an alternative for mediated electronic transfer systems in glucose oxidase biofuel cells

The bioelectrochemical behavior of three triphenylmethane (TPM) dyes commonly used as pH indicators, and their application in mediated electron transfer systems for glucose oxidase bioanodes in biofuel cells was investigated. Bromophenol Blue, Bromothymol Blue, Bromocresol Green were compared bio-electrochemically against two widely used mediators, benzoquinone and ferrocene carboxy aldehyde. Biochemical studies were performed in terms of enzymatic oxidation, enzyme affinity, catalytic efficiency and co-factor regeneration. The different features of the TPM dyes as mediators are determined by the characteristics in the oxidation/reduction processes studied electrochemically. The reversibility of the oxidation/reduction processes was also established through the dependence of the voltammetric peaks with the sweep rates. All three dyes showed good performances compared to the FA and BQ when evaluated in a half enzymatic fuel cell. Potentiodynamic and power response experiments showed maxima power densities of 32.8 mu W cm(-2) for ferrocene carboxy aldehyde followed by similar values obtained for TPM dyes around 30 mu W cm(-2) using glucose and mediator concentrations of 10 mmol L(-1) and 1.0 mmol L(-1), respectively. Since no mediator consumption was observed during the bioelectrochemical process, and also good redox re-cycled processes were achieved, the use of triphenylmethane dyes is considered to be promising compared to other mediated systems used with glucose oxiclase bioanodes and/or biofuel cells. (C) 2011 Elsevier Inc. All rights reserved.

A conversão de D. José Brandão de Castro : a ação social de mediadores religiosos na Diocese de Propriá

This dissertation looked for to study the charisma of the religious mediator us " Movements of Christianity of Liberation " in the Diocese Sergipana of Propriá, during the decade from sixty to eighty. Centering our debate in the understanding of the social action, we have as main subject to understand the " poor " influence in the adoption of actions on the part of the mediators, in that public's favor, mainly in Fazenda Betume conflicts (1974) and of Santana dos Frades (1979). The hypotheses, we became pregnant that the mediators as D. José Brandão de Castro and the nun Maria Joana Hermínia exercised an important influence in the construction of the identity of the movements as CEBs, MEB and CPT in the area. Such influence was motivated by a conversion of the mediator D. Brandão, constituted starting from a relationship maintained between him and the members of the movements and proportionate for the critics and demands done by the popular ones. They resulted in actions in favor of the rural ones, what characterized the Church of Propriá as allied of the involved in the conflicts and no mere middleman. Before the collected material, we made use of the Analysis of Content using the poor " term " as analysis category, complemented by interviews done to members of the mentioned movements. Esta dissertação buscou estudar o carisma do mediador religioso nos “Movimentos de Cristianismo de Libertação” na Diocese Sergipana de Propriá, durante a década de sessenta a oitenta. Centrando nosso debate na compreensão da ação social, temos como questão principal entender a influência dos “pobres” na adoção de ações por parte do mediador, em favor desse público, principalmente nos conflitos da Fazenda Betume (1974) e de Santana dos Frades (1979). Como hipóteses, concebemos que os mediadores como D. José Brandão de Castro e a freira Maria Joana Hermínia exerceram uma importante influência na construção da identidade dos movimentos como as CEBs, o MEB e a CPT na região. Tal influência foi motivada por uma conversão do mediador D. Brandão, constituída a partir de uma relação mantida entre ele e os membros dos movimentos e proporcionada pelas críticas e demandas feita pelos populares. Elas resultaram em ações em favor dos campesinos, o que caracterizou a Igreja de Propriá como aliada dos envolvidos nos conflitos e não mera intermediária. Ante o material coletado, fizemos uso da Análise de Conteúdo utilizando o termo “pobre” como categoria de análise, complementada por entrevistas feitas à membros dos movimentos citados.

Re-imagining the museum: beyond the mausoleum

Through a range of case- studies, including studies from the UK, North America and Australia, this book moves away from the idea that museums are always "conservative" to suggest they have a long history of engaging with popular culture and addressing a variety of audiences. Andrea Whitcomb argues that museums are key mediators between high and popular culture and between government, media practitioners, cultural policy-makers and museums professionals. The book also analyses links between museums and the media, looks at the role of museums in cities and discusses the effects on museums of cultural policies.

The case for pre-mediation caucusing and a written risk analysis: an arranged marriage can be tempting.

This paper formed the basis of a presentation to the Law Institute, Victoria, on 11 November 2002. The motivation for this paper has come from the recent writings of Laurence Boulle/. J. H. Wade4. and Gegorio Billikopf-Eucina5 • In addition to the acumen contained in the writings of the three authors above, this paper is laced with assertions and anecdotal evidence derived from the authors' experience in a variety of negotiation and mediation settings.

The role of management consultation, support, and coping on nurses` health during the stress of restructuring

This study examined the impact of hospital restructuring moves on a sample of Australian nurses' health. The role of organizational support, assessed via levels of consultation with staff, social support, and nurses coping were examined as further contributors or mediators of the relationship between the impact of restructuring and nurses' health. Data from 201 hospital nurses indicated that the factors in the model explained 41% of the variance in nurses' health. “Top-down” communication style by management contributed negatively to nurses' health and increased their perceptions of the impact of restructuring. Support from peers, supervisors, and family together with seeing the demands of impact of restructuring as a challenge, contributed positively to nurses' health and reduced the level of avoidance strategies used. The implications of these findings are discussed.

Australian parents` views on their 5-6-year-old children's food choices

The home food environment is central to the development of healthy eating behaviours, but associations between the home food environment and children's food choices are not yet fully understood. The aims of this study were to explore parents' views regarding factors that influence children's food choices and parents' decision-making regarding the food they provide to their children. In-depth one-on-one interviews were conducted using a semi-structured interview schedule. Key concepts and themes were coded independently by two investigators. Participants include seventeen parents (16 mothers and 1 father) of children in their first year of formal schooling (aged 5–6 years). Five main themes emerged from the interviews: food marketing, food availability/food exposure, feeding strategies, modelling of eating and opportunities for food involvement. Parents believed that food marketing influenced their child's food preferences but differed in the ways they managed these influences. The food made available to children was also seen to influence what a child ate. Yet, although some parents believed it was the parents' role to determine what foods were made available to their child, others offered food on the basis of the child's tastes or preferences. The use of food as a reward was a feeding strategy employed by many parents. Family mealtimes were seen as an important opportunity for modelling of eating behaviour by parents. Peers were also seen to influence children's food preferences and eating behaviour. Finally, many parents believed that involving children in the preparation of food had a positive impact on children's food choices. Associations between the home food environment and children's food choices are complex and involve multiple mediators. Parents' views on the promoters and reinforcers of their decision-making regarding food and their child's food choices provide useful insights into these mediating factors. Increased understanding of these relationships is likely to enhance obesity prevention efforts.

Emotional reactions following exposure to idealized bodies predict unhealthy body change attitudes and behaviors in women and men

Objective: We explored the extent to which changes in emotional states following exposure to images of idealized bodies predict unhealthy body change attitudes and behaviors in women and men, and whether particular psychological traits mediate these effects. Method: One hundred thirty-three women and 93 men were assessed for unhealthy attitudes and behaviors related to body weight and muscles using the Eating Disorder Inventory-2 (EDI-2), the Obligatory Exercise Questionnaire, and the strategies to increase muscles subscale of the Body Change Inventory. Psychological traits assessed included body dissatisfaction (EDI-2), internalization of the thin/athletic ideal (Sociocultural Attitudes Towards Appearance Questionnaire-3), body comparison (Body Comparison Scale), self-esteem (Rosenberg Self-Esteem Inventory), depression (Beck Depression Inventory-II), and identity confusion (Self-Concept Clarity Scale). Participants were then exposed to photographs of thin female models and muscular male models, and visual analogue scales were used to measure changes in postexposure state body dissatisfaction, anger, anxiety, and depression.
Results: Postexposure increases in state anger, anxiety, depression, and body dissatisfaction correlated with drive for thinness and disordered eating symptomatology in women, while postexposure increases in state body dissatisfaction correlated with muscle development in men. Analyses revealed that internalization and body comparison mediated these relationships, with trait body dissatisfaction, trait depression, self-esteem, and self-concept/identity confusion serving as mediators for women only. Conclusion: These results are indicative of gender differences in: (a) reactions to idealized bodies; (b) psychological traits that predispose individuals to experience these reactions; and (c) types of body change behavior that are associated with these reactions.

OWDEAH: Online Web Data Extraction based on Access History

Web data extraction systems are the kernel of information mediators between users and heterogeneous Web data resources. How to extract structured data from semi-structured documents has been a problem of active research. Supervised and unsupervised methods have been devised to learn extraction rules from training sets. However, trying to prepare training sets (especially to annotate them for supervised methods), is very time-consuming. We propose a framework for Web data extraction, which logged usersrsquo access history and exploit them to assist automatic training set generation. We cluster accessed Web documents according to their structural details; define criteria to measure the importance of sub-structures; and then generate extraction rules. We also propose a method to adjust the rules according to historical data. Our experiments confirm the viability of our proposal.

Small-scale randomized controlled trials need more powerful methods of mediational analysis than the Baron-Kenny method

Objective: To devise more-effective physical activity interventions, the mediating mechanisms yielding behavioral change need to be identified. The Baron–Kenny method is most commonly used, but has low statistical power and may not identify mechanisms of behavioral change in small-to-medium size studies. More powerful statistical tests are available.
Study Design and Setting: Inactive adults (N = 52) were randomized to either a print or a print-plus-telephone intervention. Walking and exercise-related social support were assessed at baseline, after the intervention, and 4 weeks later. The Baron–Kenny and three alternative methods of mediational analysis (Freedman–Schatzkin; MacKinnon et al.; bootstrap method) were used to examine the effects of social support on initial behavior change and maintenance. Results: A significant mediational effect of social support on initial behavior change was indicated by the MacKinnon et al., bootstrap, and, marginally, Freedman–Schatzkin methods, but not by the Baron–Kenny method. No significant mediational effect of social support on maintenance of walking was found. Conclusions:  Methodologically rigorous intervention studies to identify mediators of change in physical activity are costly and labor ntensive, and may not be feasible with large samples. The use of statistically powerful tests of mediational effects in small-scale studies can inform the development of more effective interventions.

Src homology 3-domain growth factor receptor-bound 2-like (endophilin) interacting protein 1, a novel neuronal protein that regulates energy balance

To identify genes involved in the central regulation of energy balance, we compared hypothalamic mRNA from lean and obese Psammomys obesus, a polygenic model of obesity, using differential display PCR. One mRNA transcript was observed to be elevated in obese, and obese diabetic, P. obesus compared with lean animals and was subsequently found to be increased 4-fold in the hypothalamus of lethal yellow agouti (Ay/a) mice, a murine model of obesity and diabetes. Intracerebroventricular infusion of antisense oligonucleotide targeted to this transcript selectively suppressed its hypothalamic mRNA levels and resulted in loss of body weight in both P. obesus and Sprague Dawley rats. Reductions in body weight were mediated by profoundly reduced food intake without a concomitant reduction in metabolic rate. Yeast two-hybrid screening, and confirmation in mammalian cells by bioluminescence resonance energy transfer analysis, demonstrated that the protein it encodes interacts with endophilins, mediators of synaptic vesicle recycling and receptor endocytosis in the brain. We therefore named this transcript Src homology 3-domain growth factor receptor-bound 2-like (endophilin) interacting protein 1 (SGIP1). SGIP1 encodes a large proline-rich protein that is expressed predominantly in the brain and is highly conserved between species. Together these data suggest that SGIP1 is an important and novel member of the group of neuronal molecules required for the regulation of energy homeostasis.

The role of sisters in body image dissatisfaction and disordered eating

The Tripartite Influence Model (TIM) argues sociocultural agents affect body image dissatisfaction (BID) via the mediators of social comparison and internalization. BID subsequently influences disordered eating. Forty-seven Australian sister pairs (18–25 years) provided self-reports of perceived familial modeling and pressure by the sociocultural agents of mother, father and sister, social comparison, internalization, BID, bulimic behaviors, and dietary restriction. Sisters were correlated on internalization, BID, disordered eating, and parental modeling and pressure. Mothers and sisters were equally important modeling agents. Sisters were an equivalent social comparison target to peers. Consistent with the TIM, internalization and social comparison mediated familial pressure on BID. Contrary to the model, sister modeling directly affected bulimic behaviors and dietary restriction.

How socio-economic status contributes to participation in leisure-time physical activity

The aim of this cross-sectional study was to identify individual, social, and environmental contributors (mediators) to individual- and area-level differences in leisure-time physical activity across socio-economic groups. A two-stage stratified sampling design was used to recruit 20–65 year old adults (N = 2194) living in 154 census collection districts of Adelaide, Australia (overall response rate: 12%). Participants completed two surveys six months apart (response rate on the second survey: 83%). Individual-level socio-economic status (SES) was assessed using self-report measures on educational attainment, household income, and household size. Area-level SES was assessed using census data on median household income and household size for each selected census district. Bootstrap generalized linear models were used to examine associations between SES, potential mediators, and leisure-time physical activity. The product-of-coefficient test was used to estimate mediating effects. All SES measures were independently associated with potential individual and social mediators of the SES-activity relationships. Individual- and area-level income was also associated with perceived neighborhood attributes. Self-efficacy and social support for physical activity explained virtually all of the differences in physical activity across educational attainment groups. Physical barriers to walking and access to public open space contributed in part to the explanation of differences in recreational walking across income groups. Yet, self-efficacy and social support were the key mediators of the observed relationships between individual- and area-level income and physical activity. This study suggests that in order to increase physical activity participation in the more disadvantaged segments of the population, comprehensive, multilevel interventions targeting activity-related attitudes and skills as well as social and physical environments are needed.