Structure and function of DsbA, a key bacterial oxidative folding catalyst

Since its discovery in 1991, the bacterial periplasmic oxidative folding catalyst DsbA has been the focus of intense research. Early studies addressed why it is so oxidizing and how it is maintained in its less stable oxidized state. The crystal structure of Escherichia coli DsbA (EcDsbA) revealed that the oxidizing periplasmic enzyme is a distant evolutionary cousin of the reducing cytoplasmic enzyme thioredoxin. Recent significant developments have deepened our understanding of DsbA function, mechanism, and interactions: the structure of the partner membrane protein EcDsbB, including its complex with EcDsbA, proved a landmark in the field. Studies of DsbA machineries from bacteria other than E. coli K-12 have highlighted dramatic differences from the model organism, including a striking divergence in redox parameters and surface features. Several DsbA structures have provided the first clues to its interaction with substrates, and finally, evidence for a central role of DsbA in bacterial virulence has been demonstrated in a range of organisms. Here, we review current knowledge on DsbA, a bacterial periplasmic protein that introduces disulfide bonds into diverse substrate proteins and which may one day be the target of a new class of anti-virulence drugs to treat bacterial infection. Antioxid. Redox Signal. 14, 1729–1760.

DSB proteins and bacterial pathogenicity

If DNA is the information of life, then proteins are the machines of life — but they must be assembled and correctly folded to function. A key step in the protein-folding pathway is the introduction of disulphide bonds between cysteine residues in a process called oxidative protein folding. Many bacteria use an oxidative protein-folding machinery to assemble proteins that are essential for cell integrity and to produce virulence factors. Although our current knowledge of this machinery stems largely from Escherichia coli K-12, this view must now be adjusted to encompass the wider range of disulphide catalytic systems present in bacteria.

Human glutathione S-transferase T1-1 enhances mutagenicity of 1,2-dibromoethane, dibromomethane and 1,2,3,4-diepoxybutane in Salmonella typhimurium

The rat theta class glutathione S-transferase (GST) 5-5 has been shown to affect the mutagenicity of halogenated alkanes and epoxides. In Salmonella typhimurium TA1535 expressing the rat GST5-5 the number of revertants was increased compared to the control strain by CH2Br2, ethylene dibromide (EDB) and 1,2,3,4-diepoxybutane (BDE); in contrast, mutagenicity of 1,2-epoxy-3-(4'-nitrophenoxy)propane (EPNP) was reduced. S.typhimurium TA1535 cells were transformed with an expression plasmid carrying the cDNA of the human theta ortholog GST1-1 either in sense or antisense orientation, the latter being the control. These transformed bacteria were utilized for mutagenicity assays. Mutagenicity of EDB, BDE, CH2Br2, epibromohydrin and 1,3-dichloroacetone was higher in the S.typhimurium TA1535 expressing GSTT1-1 than in the control strain. The expression of active enzyme did not affect the mutagenicity of 1,2-epoxy-3-butene or propylene oxide, GSTT1-1 expression reduced the mutagenicity of EPNP. Glutathione S-transferase 5-5 and GSTT1-1 modulate genotoxicity of several industrially important chemicals in the same way. Polymorphism of the GSTT1 locus in humans may therefore cause differences in cancer susceptibility between the two phenotypes.

Paediatric Nursing in Australia

Paediatric Nursing in Australia equips students with the essential skills and knowledge to become paediatric, child and youth health nurses across a variety of clinical and community settings. It prepares students for critical thinking and problem solving within this field by emphasising contemporary issues impacting on the health of children, young people and their families. Written by a team of experienced paediatric nurses, the content is based on themes that align with Australian standards of competence and expectations of paediatric nursing: communication, family involvement and evidence-based practice. Comprehensive yet concise, the text examines the integration of theoretical and clinical components of nursing knowledge. To enhance learning, chapters feature case studies, reflection points and learning activities. An essential resource for nursing students, this text is grounded in current care delivery and professional issues for care of the child to prepare future nurses for evidence-based practice in paediatric settings throughout Australia. • Prepares students for critical thinking and problem solving within paediatric, child and youth health nursing by emphasising contemporary issues that impact on the health of children and young people and their families • Written by a team of experienced paediatric nurses • Enhances learning by providing illustrative case studies, reflection points and learning activities in each chapter

Management of atopic dermatitis in children : evaluation of parents' self-efficacy, outcome expectations, and self-reported task performance using the Child Eczema Management Questionnaire

Child behaviour management is crucial to successful treatment of atopic dermatitis. This study tested relationships between parents’ self-efficacy, outcome expectations, and self-reported task performance when caring for a child with atopic dermatitis. Using a cross-sectional study design, a community-based convenience sample of 120 parents participated in pilot-testing of the Child Eczema Management Questionnaire - a self-administered questionnaire which appraises parents’ self-efficacy, outcome expectations, and self-reported task performance when managing atopic dermatitis. Overall, parents’ self-reported confidence and success with performing routine management tasks was greater than that for managing their child’s symptoms and behaviour. Therewas a positive relationship between time since diagnosis and self-reported performance of routine management tasks; however, success with managing the child’s symptoms and behaviour did not improve with illness duration. Longer time since diagnosis was also associated with more positive outcome expectations of performing tasks that involved others in the child’s care (i.e. healthcare professionals, or the child themselves). This study provides the foundation for further research examining relationships between child, parent, and family psychosocial variables, parent management of atopic dermatitis, and child health outcomes. Improved understanding of these relationships will assist healthcare providers to better support parents and families caring for children with atopic dermatitis. KEYWORDS

Trait resilience fosters adaptive coping when control opportunities are high : implications for the motivating potential of active work

Purpose: We examine the interaction between trait resilience and control in predicting coping and performance. Drawing on a person–environment fit perspective, we hypothesized resilient individuals would cope and perform better in demanding work situations when control was high. In contrast, those low in resilience would cope and perform better when control was low. Recognizing the relationship between trait resilience and performance also could be indirect, adaptive coping was examined as a mediating mechanism through which high control enables resilient individuals to demonstrate better performance. Methodology: In Study 1 (N = 78) and Study 2 (N = 94), participants completed a demanding inbox task in which trait resilience was measured and high and low control was manipulated. Study 3 involved surveying 368 employees on their trait resilience, control, and demand at work (at Time 1), and coping and performance 1 month later at Time 2. Findings: For more resilient individuals, high control facilitated problem-focused coping (Study 1, 2, and 3), which was indirectly associated with higher subjective performance (Study 1), mastery (Study 2), adaptive, and proficient performance (Study 3). For more resilient individuals, high control also facilitated positive reappraisal (Study 2 and 3), which was indirectly associated with higher adaptive and proficient performance (Study 3). Implications: Individuals higher in resilience benefit from high control because it enables adaptive coping. Originality/value: This research makes two contributions: (1) an experimental investigation into the interaction of trait resilience and control, and (2) investigation of coping as the mechanism explaining better performance.

Forest reflections

Interactive art installation Artist in Residence Queensland Government grant. Awarded June 2011 for period July-September 2011. This project involved co-creating an interactive artwork on site and in the forest with Grovely Primary school children aged 6-10, some with high needs. Affiliated with the United Nations International Year of the Forest. Final work is tangible, real-time visualization created using participatory design methods.

Mark form experience

Weblog of participatory arts Community interactive art project with Cerebral Palsy League. Regional Arts Development grant, Queensland Government. Awarded June 2012. This project has involved exploring and visualising participants’ movements through their drawings and co-designing an interactive, visualisation artwork based on these gestures and images.