Comparative analysis of FimB and FimE recombinase activity

FimB and FimE are site-specific recombinases, part of the λ integrase family, and invert a 314 bp DNA switch that controls the expression of type 1 fimbriae in Escherichia coli. FimB and FimE differ in their activity towards the fim switch, with FimB catalysing inversion in both directions in comparison to the higher-frequency but unidirectional on-to-off recombination catalysed by FimE. Previous work has demonstrated that FimB, but not FimE, recombination is completely inhibited in vitro and in vivo by a regulator, PapB, expressed from a distinct fimbrial locus. The aim of this work was to investigate differences between FimB and FimE activity by exploiting the differential inhibition demonstrated by PapB. The research focused on genetic changes to the fim switch that alter recombinase binding and its structural context. FimB and FimE still recombined a switch in which the majority of fimS DNA was replaced with a larger region of non-fim DNA. This demonstrated a minimal requirement for FimB and FimE recombination of the Fim binding sites and associated inverted repeats. With the original leucine-responsive regulatory protein (Lrp) and integration host factor (IHF)-dependent structure removed, PapB was now able to inhibit both recombinases. The relative affinities of FimB and FimE were determined for the four ‘half sites’. This analysis, along with the effect of extensive swaps and duplications of the half sites on recombination frequency, demonstrated that FimB recruitment and therefore subsequent activity was dependent on a single half site and its context, whereas FimE recombination was less stringent, being able to interact initially with two half sites with equally high affinity. While increasing FimB recombination frequencies failed to overcome PapB repression, mutations made in recombinase binding sites resulted in inhibition of FimE recombination by PapB. Overall, the data support a model in which the recombinases differ in loading order and co-operative interactions. PapB exploits this difference and FimE becomes susceptible when its normal loading is restricted or changed.

A comparative study of the proliferation and osteogenic differentiation of human periodontal ligament cells cultured on β-TCP ceramics and demineralized bone matrix with or without osteogenic inducers in vitro

The repair of bone defects that result from periodontal diseases remains a clinical challenge for periodontal therapy. β-tricalcium phosphate (β-TCP) ceramics are biodegradable inorganic bone substitutes with inorganic components that are similar to those of bone. Demineralized bone matrix (DBM) is an acid-extracted organic matrix derived from bone sources that consists of the collagen and matrix proteins of bone. A few studies have documented the effects of DBM on the proliferation and osteogenic differentiation of human periodontal ligament cells (hPDLCs). The aim of the present study was to investigate the effects of inorganic and organic elements of bone on the proliferation and osteogenic differentiation of hPDLCs using three-dimensional porous β-TCP ceramics and DBM with or without osteogenic inducers. Primary hPDLCs were isolated from human periodontal ligaments. The proliferation of the hPDLCs on the scaffolds in the growth culture medium was examined using a Cell‑Counting kit‑8 (CCK-8) and scanning electron microscopy (SEM). Alkaline phosphatase (ALP) activity and the osteogenic differentiation of the hPDLCs cultured on the β-TCP ceramics and DBM were examined in both the growth culture medium and osteogenic culture medium. Specific osteogenic differentiation markers were examined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). SEM images revealed that the cells on the β-TCP were spindle-shaped and much more spread out compared with the cells on the DBM surfaces. There were no significant differences observed in cell proliferation between the β-TCP ceramics and the DBM scaffolds. Compared with the cells that were cultured on β-TCP ceramics, the ALP activity, as well as the Runx2 and osteocalcin (OCN) mRNA levels in the hPDLCs cultured on DBM were significantly enhanced both in the growth culture medium and the osteogenic culture medium. The organic elements of bone may exhibit greater osteogenic differentiation effects on hPDLCs than the inorganic elements.

Setting the agenda, influencing public opinion, and advocating for social change

This study seeks to contribute to the systematic explanation of journalists’ professional role orientations. Focusing on three aspects of journalistic interventionism – the importance of setting the political agenda, influencing public opinion and advocating for social change – multilevel analyses found substantive variation in interventionism at the individual level of the journalist, the level of the media organizations, and the societal level. Based on interviews with 2100 journalists from 21 countries, findings affirm theories regarding a hierarchy of influences in news work. We found journalists to be more willing to intervene in society when they work in public media organizations and in countries with restricted political freedom. An important conclusion of our analysis is that journalists’ professional role orientations are also rooted within perceptions of cultural and social values. Journalists were more likely to embrace an interventionist role when they were more strongly motivated by the value types of power, achievement and tradition.

Regulating Workplace Risks: A Comparative Study of Inspection Regimes in Times of Change

Regulating Workplace Risks is a study of regulatory inspection of occupational health and safety (OHS) and its management in five countries – Australia, Canada (Québec), France, Sweden and the UK – during a time of major change. It examines the implications of the shift from specification to process based regulation, in which attention has been increasingly directed to the means of managing OHS more systematically at a time in which a major restructuring of work has occurred in response to the globalised economy. These changes provide both the context and material for a wider discussion of the nature of regulation and regulatory inspection and their role in protecting the health, safety and well-being of workers in advanced market economies.

Family structure and change through middle childhood : the impact on children's adjustment and achievement

This research project investigated the influence of family transitions on children's adjustment and school achievement across the primary school years, in single-parent, re-partnered and two-parent families. The quality of children's relationships with parents, teachers and peers were predictive of more positive outcomes, regardless of family structure. The research analysed data from the Kindergarten Cohort participating in Growing Up in Australia: The Longitudinal Study of Australian Children. Across the age span of the children studied, cumulative effects of any residential or school changes, or decreased family income, associated with family transitions, were more likely to predict poorer child outcomes in behaviour adjustment and school achievement.

Suicide, statistics and the coroner: A comparative study of death investigations

Australia has a significantly higher suicide rate than England. Rather than accepting that this ‘statistical fact’ is a direct reflection of some positivist truth, this paper begins with the premise that how suicide is counted depends upon what counts as suicide. This study involves semi-structured interviews with coroners both in Australia and England, as well as observations at inquests. Important differences between the two coronial systems include: first, quite different logics of operation; second, the burden of proof for reaching a finding of suicide is significantly higher in England; and third, the presence of family members at English inquests results in far greater pressure being brought to bear upon coroners. These combined factors result in a reduced likelihood of English coroners reaching a finding of suicide. The conclusions are twofold. First, this research supports existing criticisms of comparative suicide statistics. Second, this research adds theoretical weight to criticisms of positivist analyses of social phenomena.

Comparative studies made simple in GPFlow

This work describes recent extensions to the GPFlow scientific workflow system in development at MQUTeR (www.mquter.qut.edu.au), which facilitate interactive experimentation, automatic lifting of computations from single-case to collection-oriented computation and automatic correlation and synthesis of collections. A GPFlow workflow presents as an acyclic data flow graph, yet provides powerful iteration and collection formation capabilities.

Self-reflection as an intervention to influence achievement goal orientations and intrinsic motivation

In the context of physical activity, intrinsic motivation refers to the inherent satisfaction associated with participation in the activity. Interest-enjoyment, perceived competence, and effort have been identified as three underlying components of intrinsic motivation. Achievement goal theory stipulates that achievement goals guide our beliefs and behavior. The two main achievement goal orientations identified in the sport and physical activity literature are task and ego orientations. A person with a strong task orientation defines success in self-referenced terms, as improving one’s own performance or mastering new skills. Someone with a strong ego orientation defines success normatively, as being better than others. The majority of research suggests that having a strong task orientation is a good thing, whether with regard to motivationally adaptive responses, sources of sport confidence, students’ satisfaction with learning, or the use of cognitive and self-regulatory strategies. Although the literature supporting the potential benefits of having a strong task orientation is vast, considerably less research has tested interventions designed to strengthen task orientations and intrinsic motivation. A climate that emphasises individual mastery has resulted in increased interest-enjoyment and perceived competence, whereas an emphasis on competition and comparison with others has resulted in a decrease in interest-enjoyment and an increase in tension-pressure. One possible intervention is the use of structured self-reflection. Using self-reflection sheets that cause respondents to focus on specific elements of technique or skills, and rate one’s own performance, should theoretically promote a task focus. Hanrahan suggested that engaging in self-reflection may enhance intrinsic motivation. Perceived competence could be positively affected, as self-analysis and self-monitoring have been found to positively influence the acquisition of physical skills. The purpose of this study was to determine if the use of structured self-reflection in community dance classes would influence achievement goal orientations or levels of intrinsic motivation.

Dulux Study Tour for Australian Achievement in Architecture Awards Recipient Report 2008

The Dulux Study Tour is a collaborative initiative between Dulux, the Australian Institute of Architects and EmAGN. Each year five (5) architectural professionals (within 10 years of graduation) are selected to join the Dulux Study Tour, an international tour visiting leading architectural firms, recently completed projects and architecturally rich locations. The Dulux Study Tour acknowledges the contribution the selected emerging architects make to practice, research and the culture of architecture, and seeks to further inspire the next generation of emerging architects.

Reconsidering pro bono : a comparative analysis of protocols in Australia, the united states, the United Kingdom and Singapore

As of now, there is little evidence on the questions of whether pro bono services are effective, whether lawyer charity is a cheaper way to provide them (because it does cost money to do pro bono), or whether it would in fact be more efficient and effective if firms and attorneys stopped giving their time and instead donated money to the organizations already specializing in these clients and causes. Pro bono may or may not be an efficient way of doing socially important work; at this point, we simply do not know

Rethinking restrictive practices : a comparative analysis

This paper undertakes the first comparative analysis of restrictive practices legislation in Australia. This legislation, which regulates practices used to manage ‘challenging behaviours’ of people with intellectual disability or cognitive impairment, currently exists in four Australian jurisdictions. The paper demonstrates the gaps in coverage of this legislation and the wide variation of law nationally. We argue that legislation governing restrictive practices is needed, it should regulate the provision of all restrictive practices (not just some) and that there should be a national consistent approach.