The role of immunoglobulins and their transporters in urogenital Chlamydial infections

Chlamydia trachomatis infections of the male and female reproductive tracts are the world's leading sexually transmitted bacterial disease, and can lead to damaging pathology, scarring and infertility. The resolution of chlamydial infection requires the development of adaptive immune responses to infection, and includes cell-mediated and humoral immunity. Whilst cluster of differentiation (CD)4+ T cells are known to be essential in clearance of infection [1], they are also associated with immune cell infiltration, autoimmunity and infertility in the testes [2-3]. Conversely, antibodies are less associated with inflammation, are readily transported into the reproductive tracts, and can offer lumenal neutralization of chlamydiae prior to infection. Antibodies, or immunoglobulins (Ig), play a supportive role in the resolution of chlamydial infections, and this thesis sought to define the function of IgA and IgG, against a variety of chlamydial antigens expressed during the intracellular and extracellular stages of the chlamydial developmental cycle. Transport of IgA and IgG into the mucosal lumen is facilitated by receptor-mediated transcytosis yet the expression profile (under normal conditions and during urogenital chlamydial infection) of the polymeric immunoglobulin receptor (pIgR) and the neonatal Fc receptor (FcRn) remains unknown. The expression profile of pIgR and FcRn in the murine male reproductive tract was found to be polarized to the lower and upper reproductive tract tissues respectively. This demonstrates that the two receptors have a tissue tropism, which must be considered when targeting pathogens that colonize different sites. In contrast, the expression of pIgR and FcRn in the female mouse was found to be distributed in both the upper and lower reproductive tracts. When urogenitally infected with Chlamydia muridarum, both male and female reproductive tracts up-regulated expression of pIgR and down-regulated expression of FcRn. Unsurprisingly, the up-regulation of pIgR increased the concentration of IgA in the lumen. However, down-regulation of FcRn, prevented IgG uptake and led to an increase or pooling of IgG in lumenal secretions. As previous studies have identified the importance of pIgR-mediated delivery of IgA, as well as the potential of IgA to bind and neutralize intracellular pathogens, IgA against a variety of chlamydial antigens was investigated. The protection afforded by IgA against the extracellular antigen major outer membrane protein (MOMP), was found to be dependent on pIgR expression in vitro and in vivo. It was also found that in the absence of pIgR, no protection was afforded to mice previously immunized with MOMP. The protection afforded from polyclonal IgA against the intracellular chlamydial antigens; inclusion membrane protein A (IncA), inclusion membrane proteins (IncMem) and secreted chlamydial protease-like activity factor (CPAF) were produced and investigated in vitro. Antigen-specific intracellular IgA was found to bind to the respective antigen within the infected cell, but did not significantly reduce inclusion formation (p > 0.05). This suggests that whilst IgA specific for the selected antigens was transported by pIgR to the chlamydial inclusion, it was unable to prevent growth. Similarly, immunization of male mice with intracellular chlamydial antigens (IncA or IncMem), followed by depletion CD4+ T cells, and subsequent urogenital C. muridarum challenge, provided minimal pIgR-mediated protection. Wild type male mice immunized with IncA showed a 57 % reduction (p < 0.05), and mice deficient in pIgR showed a 35 % reduction (p < 0.05) in reproductive tract chlamydial burden compared to control antigen, and in the absence of CD4+ T cells. This suggests that pIgR and secretory IgA (SIgA) were playing a protective role (21 % pIgR-mediated) in unison with another antigen-specific immune mechanism (36 %). Interestingly, IgA generated during a primary respiratory C. muridarum infection did not provide a significant amount of protection to secondary urogenital C. muridarum challenge. Together, these data suggest that IgA specific for an extracellular antigen (MOMP) can play a strong protective role in chlamydial infections, and that IgA targeting intracellular antigens is also effective but dependent on pIgR expression in tissues. However, whilst not investigated here, IgA targeting and blocking other intracellular chlamydial antigens, that are more essential for replication or type III secretion, may be more efficacious in subunit vaccines. Recently, studies have demonstrated that IgG can neutralize influenza virus by trafficking IgG-bound virus to lysosomes [4]. We sought to determine if this process could also traffic chlamydial antigens for degradation by lysosomes, despite Chlamydia spp. actively inhibiting fusion with the host endocytic pathway. As observed in pIgR-mediated delivery of anti-IncA IgA, FcRn similarly transported IgG specific for IncA which bound the inclusion membrane. Interestingly, FcRn-mediated delivery of anti-IncA IgG significantly decreased inclusion formation by 36 % (p < 0.01), and induced aberrant inclusion morphology. This suggests that unlike IgA, IgG can facilitate additional host cellular responses which affect the intracellular niche of chlamydial growth. Fluorescence microscopy revealed that IgG also bound the inclusion, but unlike influenza studies, did not induce the recruitment of lysosomes. Notably, anti-IncA IgG recruited sequestosomes to the inclusion membrane, markers of the ubiquitin/proteasome pathway and major histocompatibility complex (MHC) class I loading. To determine if the protection against C. muridarum infection afforded by IncA IgG in vitro translated in vivo, wild type mice and mice deficient in functional FcRn and MHC-I, were immunized, depleted of CD4+, and urogenitally infected with C. muridarum. Unlike in pIgR-deficient mice, the protection afforded from IncA immunization was completely abrogated in mice lacking functional FcRn and MHC-I/CD8+. Thus, both anti-IncA IgA and IgG can bind the inclusion in a pIgR and FcRn-mediated manner, respectively. However, only IgG mediates a higher reduction in chlamydial infection in vitro and in vivo suggesting more than steric blocking of IncA had occurred. Unlike anti-MOMP IgA, which reduced chlamydial infection of epithelial cells and male mouse tissues, IgG was found to enhance infectivity in vitro, and in vivo. Opsonization of EBs with MOMP-IgG enhanced inclusion formation of epithelial cells in a MOMP-IgG dose-dependent and FcRn-dependent manner. When MOMP-IgG opsonized EBs were inoculated into the vagina of female mice, a small but non-significant (p > 0.05) enhancement of cervicovaginal C. muridarum shedding was observed three days post infection in mice with functional FcRn. Interestingly, infection with opsonized EBs reduced the intensity of the peak of infection (day six) but protracted the duration of infection by 60 % in wild type mice only. Infection with EBs opsonized in IgG also significantly increased (p < 0.05) hydrosalpinx formation in the oviducts and induced lymphocyte infiltration uterine horns. As MOMP is an immunodominant antigen, and is widely used in vaccines, the ability of IgG specific to extracellular chlamydial antigens to enhance infection and induce pathology needs to be considered. Together, these data suggest that immunoglobulins play a dichotomous role in chlamydial infections, and are dependent on antigen specificity, FcRn and pIgR expression. FcRn was found to be highly expressed in upper male reproductive tract, whilst pIgR was dominantly expressed in the lower reproductive tract. Conversely, female mice expressed FcRn and pIgR in both the lower and upper reproductive tracts. In response to a normal chlamydial infection, pIgR is up-regulated increasing secretory IgA release, but FcRn is down-regulated preventing IgG uptake. Similarly to other studies [5-6], we demonstrate that IgA and IgG generated during primary chlamydial infections plays a minor role in recall immunity, and that antigen-specific subunit vaccines can offer more protection. We also show that both IgA and IgG can be used to target intracellular chlamydial antigens, but that IgG is more effective. Finally, IgA against the extracellular antigen MOMP can afford protection, whist IgG plays a deleterious role by increasing infectivity and inducing damaging immunopathology. Further investigations with additional antigens or combination subunit vaccines will enhance our understanding the protection afforded by antibodies against intracellular and extracellular pathogenic antigens, and help improve the development of an efficacious chlamydial vaccine.

The role of EBV-encoded microRNAs in B cell differentiation

Epstein Barr virus (EBV) is a common γ-herpes virus, infecting approximately 90% of the world‟s population. It is also one of the first known viruses known to be oncogenic, and is associated with a number of tumour types, primarily lymphomas. MicroRNAs (miRNAs) are post-transcriptional regulators of gene expression and many human miRNAs have been associated with the development of malignancies including cancer. EBV was the first human virus identified to express miRNAs and encodes more than 40 miRNAs within its genome. Yet, an understanding of the targets of EBV-miRNAs, and thereby the function of them in pathogenesis remains sadly limited. This study identifies a potential novel target of EBV-miRNAs, MECP2 and characterises the miRNA:mRNA interactions between two previously identified novel targets; Bim and EBF1. In particular, this study focuses upon the interaction between EBF1 and the EBV-miRNA BART11-5p, demonstrating a 151bp region of the EBF1 3‟UTR that is capable of mediating the silencing of luciferase expression by BART11-5p but is not capable of silencing a full length EBF1-3‟UTR luciferase construct. This study provides evidence that EBF1 may be a target of one or more EBV-miRNAs.

The role of fathers in child feeding : perceived responsibility and predictors of participation

Background The role of fathers in shaping their child’s eating behaviour and weight status through their involvement in child feeding has rarely been studied. This study aims to describe the fathers’ perceived responsibility for child feeding, and to identify predictors of how frequently fathers eat meals with their child. Methods Four hundred and thirty-six Australian fathers (M age=37 years, SD=6 years; 34% university educated) of a 2-5 year old child (M age=3.5 years, SD=0.9 years; 53% boys) were recruited via contact with mothers enrolled in existing research projects or a University staff and student email list. Data were collected from fathers via a self-report questionnaire. Descriptive and hierarchical linear regression analyses were conducted. Results The majority of fathers reported that the family often/mostly ate meals together (79%). Many fathers perceived that they were responsible at least half of the time for feeding their child in terms of organizing meals (42%); amount offered (50%) and deciding if their child eats the ‘right kind of foods’ (60%). Time spent in paid employment was inversely associated with how frequently fathers ate meals with their child (β=-0.23, p<0.001); however, both higher perceived responsibility for child feeding (β=-0.16, p<0.004) and a more involved and positive attitude toward their role as a father (β=0.20, p<0.001) were positively related to how often they ate meals with their child, adjusting for a range of paternal and child covariates, including time spent in paid employment. Conclusions Fathers from a broad range of educational backgrounds appear willing to participate in research studies on child feeding. Most fathers were engaged and involved in family meals and child feeding. This suggests that fathers, like mothers, should be viewed as potential agents for the implementation of positive feeding practices within the family.

The role of the internet in testimony : the case of the ‘Forgotten Australians’

This paper examines the case of the Forgotten Australians as an opportunity to examine the role of the internet in the presentation of testimony. ‘Forgotten Australians’ are a group who suffered abuse and neglect after being removed from their parents – either in Australia or in the UK - and placed in Church and State run institutions in Australia between 1930 and 1970. The campaign by this profoundly marginalised group coincided with the decade in which the opportunities of Web 2.0 were seen to be diffusing throughout different social groups, and were considered a tool for social inclusion. We outline a conceptual framework that positions the role of the internet as an environment in which the difficult relationships between painful past experiences and contemporary injunctions to remember them, are negotiated. We then apply this framework to the analysis of case examples of posts and interaction on websites with web 2.0 functionality: YouTube and the National Museum of Australia. The analysis points to commonalities and differences in the agency of the internet in these two contexts, arguing that in both cases the websites provided support for the development of a testimony-like narrative and the claiming, sharing and acknowledgement of loss.

The role of motivation and motivational strategies in Saudi students' communicative competence in English

This study explored how motivation and motivational strategies influence the communicative competence of students from Saudi Arabia. Participants included Saudi students enrolled in English courses in Australian educational institutions, and Saudi students living in Saudi Arabia studying in English language institutes in Saudi Arabia. Phase One involved interviews with16 participants. In Phase Two, 279 participants completed a questionnaire. Findings included differences between participants’ measured and self-reported communicative competence, with the Australian group having higher levels of measured and self-reported communicative competence. In addition, motivation teaching strategies were found to affect students’ motivation, but not their communicative competence.

The role of nurse educators in student clinical education in Saudi Arabia

Introduction: Clinical education is considered a significant part of the learning process for nursing students. There is, however, no research that has explored this area of learning in Saudi Arabia. Theoretical Framework: Informed by a symbolic interactionist framework, this research explored the role of nurse educators in student clinical education in Saudi Arabia. Method: Using Glaserian grounded theory methods the data were derived from 14 face-to-face interviews with nurse educators from both hospital and faculty settings in King Abdu-Aziz University (KAU) and King Abdu-Aziz University Hospital (KAUH). Findings: The findings of the research are represented in the core category Redefining Identity Work and its two constituent categories Questioning the Situation and Creating Role Identity. The core and sub- categories were generated through a theoretical exploration of the identity work of nurse educators in Saudi Arabia. Conclusion: The social identity of the nurse educators was mediated culturally and socially within the hospital and university contexts and Saudi Arabian culture. In light of an increased understanding of the identity and role of nurse educators in clinical education in Saudi Arabia, the research presents implications and recommendations that may contribute to the development of nursing education as a coherent health care profession that is perceived as a desirable career option for Saudi women and men.

Low formalin concentrations induce fine-tuned responses that are sex and age-dependent : a developmental study

The formalin test is increasingly applied as a model of inflammatory pain using high formalin concentrations (5–15%). However, little is known about the effects of low formalin concentrations on related behavioural responses. To examine this, rat pups were subjected to various concentrations of formalin at four developmental stages: 7, 13, 22, and 82 days of age. At postnatal day (PND) 7, sex differences in flinching but not licking responses were observed with 0.5% formalin evoking higher flinching in males than in females. A dose response was evident in that 0.5% formalin also produced higher licking responses compared to 0.3% or 0.4% formalin. At PND 13, a concentration of 0.8% formalin evoked a biphasic response. At PND 22, a concentration of 1.1% evoked higher flinching and licking responses during the late phase (10–30 min) in both males and females. During the early phase (0–5 min), 1.1% evoked higher licking responses compared to 0.9% or 1% formalin. 1.1% formalin produced a biphasic response that was not evident with 0.9 or 1%. At PND 82, rats displayed a biphasic pattern in response to three formalin concentrations (1.25%, 1.75% and 2.25%) with the presence of an interphase for both 1.75% and 2.25% but not for 1.25%. These data suggest that low formalin concentrations induce fine-tuned responses that are not apparent with the high formalin concentration commonly used in the formalin test. These data also show that the developing nociceptive system is very sensitive to subtle changes in formalin concentrations.

Rating defense mega-project success : the role of personal attributes and stakeholder relationships

In this paper, we develop and test a model of the relationships between mega-project leaders’ personal attributes and their ratings of project success in the context of the Australian defense industry. In our model, emotional intelligence, cognitive flexibility, and systemic thinking were hypothesized to be related to project success ratings, mediated by internal and external stakeholder relationships. We tested the model in an online survey study of 373 mega-project leaders. Results were that emotional intelligence and cognitive flexibility were found to be related to the quality of mega-project leader’s relationships with both internal and external stakeholders; and that these relationships in turn were found to be associated with the project leaders’ ratings of project success. We found however that systemic thinking had no relationship with either stakeholder relationships or ratings of project success. We conclude with a discussion of the implications of these findings and make recommendations for future research. In particular, additional research is needed to examine the contribution of a wider range of competencies on stakeholder relationships and project success in mega-projects, and that there is also a need for research in future to attempt to use more objective ratings of project success.

Impact of extracellular matrix derived from osteoarthritis subchondral bone osteoblasts on osteocytes : role of integrinβ1 and focal adhesion kinase signaling cues

INTRODUCTION: Our recent study indicated that subchondral bone pathogenesis in osteoarthritis (OA) is associated with osteocyte morphology and phenotypic abnormalities. However, the mechanism underlying this abnormality needs to be identified. In this study we investigated the effect of extracellular matrix (ECM) produced from normal and OA bone on osteocytic cells function. METHODS: De-cellularized matrices, resembling the bone provisional ECM secreted from primary human subchondral bone osteoblasts (SBOs) of normal and OA patients were used as a model to study the effect on osteocytic cells. Osteocytic cells (MLOY4 osteocyte cell line) cultured on normal and OA derived ECMs were analyzed by confocal microscopy, scanning electron microscopy (SEM), cell attachment assays, zymography, apoptosis assays, qRT-PCR and western blotting. The role of integrinβ1 and focal adhesion kinase (FAK) signaling pathways during these interactions were monitored using appropriate blocking antibodies. RESULTS: The ECM produced by OA SBOs contained less mineral content, showed altered organization of matrix proteins and matrix structure compared with the matrices produced by normal SBOs. Culture of osteocytic cells on these defective OA ECM resulted in a decrease of integrinβ1 expression and the de-activation of FAK cell signaling pathway, which subsequently affected the initial osteocytic cell's attachment and functions including morphological abnormalities of cytoskeletal structures, focal adhesions, increased apoptosis, altered osteocyte specific gene expression and increased Matrix metalloproteinases (MMP-2) and -9 expression. CONCLUSION: This study provides new insights in understanding how altered OA bone matrix can lead to the abnormal osteocyte phenotypic changes, which is typical in OA pathogenesis.

Sex-based comparisons of myofibrillar protein synthesis after resistance exercise in the fed state

Sex-based comparisons of myofibrillar protein synthesis after resistance exercise in the fed state. J Appl Physiol 112: 1805-1813, 2012. First published March 1, 2012; doi:10.1152/japplphysiol.00170.2012.- We made sex-based comparisons of rates of myofibrillar protein synthesis (MPS) and anabolic signaling after a single bout of high-intensity resistance exercise. Eight men (20 ± 10 yr, BMI = 24.3 ± 2.4) and eight women (22 ± 1.8 yr, BMI = 23.0 ± 1.9) underwent primed constant infusions of L-[ring-13C6]phenylalanine on consecutive days with serial muscle biopsies. Biopsies were taken from the vastus lateralis at rest and 1, 3, 5, 24, 26, and 28 h after exercise. Twenty-five grams of whey protein was ingested immediately and 26 h after exercise. We also measured exercise-induced serum testosterone because it is purported to contribute to increases in myofibrillar protein synthesis (MPS) postexercise and its absence has been hypothesized to attenuate adaptative responses to resistance exercise in women. The exercise-induced area under the testosterone curve was 45-fold greater in men than women in the early (1 h) recovery period following exercise (P < 0.001). MPS was elevated similarly in men and women (2.3- and 2.7-fold, respectively) 1-5 h postexercise and after protein ingestion following 24 h recovery. Phosphorylation of mTORSer2448 was elevated to a greater extent in men than women acutely after exercise (P = 0.003), whereas increased phosphorylation of p70S6K1Thr389 was not different between sexes. Androgen receptor content was greater in men (main effect for sex, P = 0.049). Atrogin-1 mRNA abundance was decreased after 5 h recovery in both men and women (P < 0.001), and MuRF-1 expression was elevated in men after protein ingestion following 24 h recovery (P = 0.003). These results demonstrate minor sex-based differences in signaling responses and no difference in the MPS response to resistance exercise in the fed state. Interestingly, our data demonstrate that exerciseinduced increases in MPS are dissociated from postexercise testosteronemia and that stimulation of MPS occurs effectively with low systemic testosterone concentrations in women.

The role of conflict in determining consensus on quality in Wikipedia articles

This paper presents research that investigated the role of conflict in the editorial process of the online encyclopedia, Wikipedia. The study used a grounded approach to analyzing 147 conversations about quality from the archived history of the Wikipedia article 'Australia'. It found that conflict in Wikipedia is a generative friction, regulated by references to policy as part of a coordinated effort within the community to improve the quality of articles.

Earnings management and the role of the audit committee: an investigation of the influence of cross-listing and government officials on the audit committee

This paper extends research on the corporate governance practices of transitional economies by examining whether the ability of the audit committee to constrain earnings management in Chinese firms is associated with the listing environment and the presence of government officials on the audit committee. Despite considerable regulatory reforms by the Chinese Securities Regulatory Commission, there remain incentives for Chinese firms to manage earnings. However, government initiatives to encourage domestic firms to cross-list on the Hong Kong Stock Exchange are accompanied by improved governance. We find that the expertise and independence of the audit committee for cross-listed (CL) Chinese firms are associated with lower abnormal accruals, our measure of earnings management. Both domestic only listed firms and CL Chinese firms appoint government officials as independent members on the audit committee. However, due to the political connection between government officials and the controlling shareholder (the State), these appointments can severely mitigate audit committee independence. Subsequently, we find a significant and positive association between audit committee independence and experience and earnings management when there are government officials on the audit committee.

Communication models of institutional online communities : the role of the ABC cultural intermediary

The co-creation of cultural artefacts has been democratised given the recent technological affordances of information and communication technologies. Web 2.0 technologies have enabled greater possibilities of citizen inclusion within the media conversations of their nations. For example, the Australian audience has more opportunities to collaboratively produce and tell their story to a broader audience via the public service media (PSM) facilitated platforms of the Australian Broadcasting Corporation (ABC). However, providing open collaborative production for the audience gives rise to the problem, how might the PSM manage the interests of all the stakeholders and align those interests with its legislated Charter? This paper considers this problem through the ABC’s user-created content participatory platform, ABC Pool and highlights the cultural intermediary as the role responsible for managing these tensions. This paper also suggests cultural intermediation is a useful framework for other media organisations engaging in co-creative activities with their audiences.

The role of the cultural intermediary within professional participatory communication : lessons from ABC Pool

As media institutions are encouraged to explore new production methodologies in the current economic crisis, they align with Schumpeter’s creative destruction provocation by exhibiting user-led political, organisation and socio-technical innovations. This paper highlights the significance of the cultural intermediary within the innovative, co-creative production arrangements for cultural artefacts by media professionals in institutional online communities. An institutional online community is defined as one that is housed, resourced and governed by commercial or non- commercial institutions and is not independently facilitated. Web 2.0 technologies have mobilised collaborative peer production activities for online content creation and professional media institutions face challenges in engaging participatory audiences in practices that are beneficial for all concerned stakeholders. The interests of those stakeholders often do not align, highlighting the need for an intermediary role that understands and translates the norms, rhetoric tropes and day-to-day activities between the individuals engaging in participatory communication activities for successful negotiation within the production process. This paper specifically explores the participatory relationship between the public service broadcaster (PSB), the Australian Broadcasting Corporation (ABC) and one of its online communities, ABC Pool (www.abc.net.au/pool). ABC Pool is an online platform developed and resourced by the ABC to encourage co-creation between audience members engaging in the production of user-generated content (UGC) and the professional producers housed within the ABC Radio Division. This empirical research emerges from a three-year research project where I employed an ethnographic action research methodology and was embedded at the ABC as the community manager of ABC Pool. In participatory communication environments, users favour meritocratic heterarchical governance over traditional institutional hierarchical systems (Malaby 2009). A reputation environment based on meritocracy requires an intermediary to identify the stakeholders, understand their interests and communicate effectively between them to negotiate successful production outcomes (Bruns 2008; Banks 2009). The community manager generally occupies this role, however it has emerged that other institutional production environments also employ an intermediary role under alternative monikers(Hutchinson 2012). A useful umbrella term to encompass the myriad of roles within this space is the cultural intermediary. The ABC has experimented with three institutional online community governance models that engage in cultural intermediation in differing decentralised capacities. The first and most closed is a single point of contact model where one cultural intermediary controls all of the communication of the participatory project. The second is a model of multiple cultural intermediaries engaging in communication between the institutional online community stakeholders simultaneously. The third is most open yet problematic as it promotes and empowers community participants to the level of cultural intermediaries. This paper uses the ABC Pool case study to highlight the differing levels of openness within cultural intermediation during the co-creative production process of a cultural artifact.

Communication models of institutional online communities : the role of the ABC cultural intermediary

The co-creation of cultural artefacts has been democratised given the recent technological affordances of information and communication technologies. Web 2.0 technologies have enabled greater possibilities of citizen inclusion within the media conversations of their nations. For example, the Australian audience has more opportunities to collaboratively produce and tell their story to a broader audience via the public service media (PSM) facilitated platforms of the Australian Broadcasting Corporation (ABC). However, providing open collaborative production for the audience gives rise to the problem, how might the PSM manage the interests of all the stakeholders and align those interests with its legislated Charter? This paper considers this problem through the ABC’s user-created content participatory platform, ABC Pool and highlights the cultural intermediary as the role responsible for managing these tensions. This paper also suggests cultural intermediation is a useful framework for other media organisations engaging in co-creative activities with their audiences.