Test of the enemy release hypothesis: the native magpie moth prefers a native fireweed (Senecio pinnatifolius) to its introduced congener (S.Madagascariensis)

Abstract The enemy release hypothesis predicts that native herbivores will either prefer or cause more damage to native than introduced plant species. We tested this using preference and performance experiments in the laboratory and surveys of leaf damage caused by the magpie moth Nyctemera amica on a co-occuring native and introduced species of fireweed (Senecio) in eastern Australia. In the laboratory, ovipositing females and feeding larvae preferred the native S. pinnatifolius over the introduced S. madagascariensis. Larvae performed equally well on foliage of S. pinnatifolius and S. madagascariensis: pupal weights did not differ between insects reared on the two species, but growth rates were significantly faster on S. pinnatifolius. In the field, foliage damage was significantly greater on native S. pinnatifolius than introduced S. madagascariensis. These results support the enemy release hypothesis, and suggest that the failure of native consumers to switch to introduced species contributes to their invasive success. Both plant species experienced reduced, rather than increased, levels of herbivory when growing in mixed populations, as opposed to pure stands in the field; thus, there was no evidence that apparent competition occurred.

Heparan sulfate mediates the proliferation and differentiation of rat mesenchymal stem cells

The growth and differentiation of mesenchymal stem cells is controlled by various growth factors, the activities of which can be modulated by heparan sulfates. We have previously underscored the necessity of sulfated glycosaminoglycans for the FGF-2-stimulated differentiation of osteoprogenitor cells. Here we show that exogenous application of heparan sulfate to cultures of primary rat MSCs stimulates their proliferation leading to increased expression of osteogenic markers and enhanced bone nodule formation. FGF-2 can also increase the proliferation and osteogenic differentiation of rMSCs when applied exogenously during their linear growth. However, as opposed to exogenous HS, the continuous use of FGF-2 during in vitro differentiation completely blocked rMSC mineralization. Furthermore, we show that the effects of both FGF-2 and HS are mediated through FGF receptor 1 (FGFR1) and that inhibition of signaling through this receptor arrests cell growth resulting in the cells being unable to reach the critical density necessary to induce differentiation. Interestingly, blocking FGFR1 signaling in post-confluent osteogenic cultures significantly increased calcium deposition. Taken together our data clearly suggests that FGFR1 signaling plays an important role during osteogenic differentiation, firstly by stimulating cell growth that is closely followed by an inhibitory affect once the cells have reached confluence. It also underlines the importance of HS as a co-receptor for the signaling of endogenous FGF-2 and suggests that purified glycosaminoglycans may be attractive alternatives to growth factors for improved ex vivo growth and differentiation of MSCs.

Sustained release and osteogenic potential of heparan sulfate-doped fibrin glue scaffolds within a rat cranial model

This paper explores the potential therapeutic role of the naturally occurring sugar heparan sulfate (HS) for the augmentation of bone repair. Scaffolds comprising fibrin glue loaded with 5 lg of embryonically derived HS were assessed, firstly as a release-reservoir, and secondly as a scaffold to stimulate bone regeneration in a critical size rat cranial defect. We show HS-loaded scaffolds have a uniform distribution of HS, which was readily released with a typical burst phase, quickly followed by a prolonged delivery lasting several days. Importantly, the released HS contributed to improved wound healing over a 3-month period as determined by microcomputed tomography (lCT) scanning, histology, histomorphometry, and PCR for osteogenic markers. In all cases, only minimal healing was observed after 1 and 3 months in the absence of HS. In contrast, marked healing was observed by 3 months following HS treatment, with nearly full closure of the defect site. PCR analysis showed significant increases in the gene expression of the osteogenic markers Runx2, alkaline phosphatase, and osteopontin in the heparin sulfate group compared with controls. These results further emphasize the important role HS plays in augmenting wound healing, and its successful delivery in a hydrogel provides a novel alternative to autologous bone graft and growth factorbased therapies.

Can hybridization cause local extinction : the case for demographic swamping of the Australian native, Senecio pinnatifolius, by the invasive, S. madagascariensis?

The outcome of interspecific hybridization between native and invasive species depends on the relative frequencies of parental taxa and viability of hybrid progeny. We investigated individual and population level consequences of hybridization between the Australian native, Senecio pinnatifolius, and the exotic S. madagascariensis, with AFLP markers and used this information to simulate the expected outcome of hybridization.A high frequency (range 8.3-75.6 %) of hybrids was detected in open pollinated seeds of both species, but mature hybrids were absent from sympatric populations indicating that sympatric populations represent tension zones. A hybridization advantage was observed for S. madagascariensis,where significantly more progeny than expected were sired based on proportional representation of the two species in sympatric populations. Simulations indicated S. pinnatifolius could be replaced in sympatric populations if hybridization was density dependent.For this native-exotic pair, prezygotic isolating barriers are weak, but low hybrid viability maintains a strong postzygotic barrier to introgression. Due to asymmetric hybridization, S. pinnatifolius appears under threat from demographic swamping, and local extinction is possible where it occurs in sympatry with S. madagascariensis.

Brivanib alaninate, a dual inhibitor of vascular endothelial growth factor receptor and fibroblast growth factor receptor tyrosine kinases, induces growth inhibition in mouse models of human hepatocellular carcinoma

PURPOSE: Hreceptor (VEGFR) and FGF receptor (FGFR) signaling pathways. EXPERIMENTAL DESIGN: Six different s.c. patient-derived HCC xenografts were implanted into mice. Tumor growth was evaluated in mice treated with brivanib compared with control. The effects of brivanib on apoptosis and cell proliferation were evaluated by immunohistochemistry. The SK-HEP1 and HepG2 cells were used to investigate the effects of brivanib on the VEGFR-2 and FGFR-1 signaling pathways in vitro. Western blotting was used to determine changes in proteins in these xenografts and cell lines. RESULTS: Brivanib significantly suppressed tumor growth in five of six xenograft lines. Furthermore, brivanib-induced growth inhibition was associated with a decrease in phosphorylated VEGFR-2 at Tyr(1054/1059), increased apoptosis, reduced microvessel density, inhibition of cell proliferation, and down-regulation of cell cycle regulators. The levels of FGFR-1 and FGFR-2 expression in these xenograft lines were positively correlated with its sensitivity to brivanib-induced growth inhibition. In VEGF-stimulated and basic FGF stimulated SK-HEP1 cells, brivanib significantly inhibited VEGFR-2, FGFR-1, extracellular signal-regulated kinase 1/2, and Akt phosphorylation. CONCLUSION: This study provides a strong rationale for clinical investigation of brivanib in patients with HCC.

Surrogacy and IVF

While in the past surrogacy was illegal in Queensland, since June 2010 the Surrogacy Act 2010 (Qld) (“the Act”) has made altruistic surrogacy arrangements lawful in Queensland. In addition, it provides a mechanism for transfer of legal parentage from the surrogate to the person(s) wishing to have a child (the intended parent(s)). Commercial surrogacy – where a payment, reward or other material benefit of advantage (other than the reimbursement of the “birth mother’s surrogacy costs” (s11 of the Act) is made for entering into a surrogacy arrangement – remains unlawful. The paramount guiding principle underpinning the Act is that of the wellbeing and best interests of a child born as a result of surrogacy. The Surrogacy Act 2010 (Qld) allows a single person or a couple (heterosexual or same sex couples) to enter into an agreement with a woman, and her partner (if she has one), to become pregnant with the intention that the child will be relinquished to the intended parent(s). The Act also provides a mechanism for the intended parent(s) to be legally recognised as the parent(s) of the child. In order for the intended parent(s) to be legally recognised (via a parentage order, discussed below) it must be shown that the surrogacy arrangement was entered into when all the parties were over 25 years of age and the intended parent(s) are male or, in a heterosexual or lesbian couple the female(s) are not likely to conceive or give birth to a healthy child due to medical reasons. The arrangement must be entered into before the surrogate becomes pregnant and all parties must have obtained independent legal advice and counselling about the proposed arrangement, and evidence of this is required at the time a parentage order is applied for. For the purposes of the Act it does not matter how the surrogate conceives the child or if the child is genetically related to the parties. During the period of the pregnancy, the surrogate has the right to manage her pregnancy in the way she wishes. Although she cannot profit from acting as a surrogate, section 11 states that she is entitled to surrogacy costs. These include, for example, reasonable medical costs related to pregnancy and the birth of the child; counselling and legal costs associated with the surrogacy arrangement; actual lost earnings because of leave taken during pregnancy or following birth and any reasonable travel expenses incurred. The surrogacy arrangement itself is not legally enforceable; however, obligations to pay a surrogate’s surrogacy costs are enforceable unless she chooses not to relinquish the child to the intending parents. While the Act does not specifically deal with the situation where the surrogate decides she is unprepared to relinquish the child to the intended parents, there have been examples where parties have entered into these kinds of arrangements, and the arrangements have become difficult. For example, the Family Court case of Re Evelyn (1998) FLC 92–807 involved a child born to a surrogate mother who decided not to surrender her. The child was the genetic child of the surrogate mother and the husband of the couple who had contracted with the surrogate mother. Both sets of parents brought proceedings in the court, seeking that the child live with them. In hearing the application, the court applied the paramount principle of the ‘best interests of the child’. The court made clear that there is no presumption in favour of the birth mother, although in this case the court found that the child may be better placed with the surrogate mother’s family.

Detection of bacteriophage and respiratory viruses in droplets

Influenza is a widespread disease occurring in seasonal epidemics, and each year is responsible for up to 500,000 deaths worldwide. Influenza can develop into strains which cause severe symptoms and high mortality rates, and could potentially reach pandemic status if the virus’ properties allow easy transmission. Influenza is transmissible via contact with the virus, either directly (infected people) or indirectly (contaminated objects); via reception of large droplets over short distances (one metre or less); or through inhalation of aerosols containing the virus expelled by infected individuals during respiratory activities, that can remain suspended in the air and travel distances of more than one metre (the aerosol route). Aerosol transmission of viruses involves three stages: production of the droplets containing viruses; transport of the droplets and ability of a virus to remain intact and infectious; and reception of the droplets (via inhalation). Our understanding of the transmission of influenza viruses via the aerosol route is poor, and thus our ability to prevent a widespread outbreak is limited. This study explored the fate of viruses in droplets by investigating the effects of some physical factors on the recovery of both a bacteriophage model and influenza virus. Experiments simulating respiratory droplets were carried out using different types of droplets, generated from a commonly used water-like matrix, and also from an ‘artificial mucous’ matrix which was used to more closely resemble respiratory fluids. To detect viruses in droplets, we used the traditional plaque assay techniques, and also a sensitive, quantitative PCR assay specifically developed for this study. Our results showed that the artificial mucous suspension enhanced the recovery of infectious bacteriophage. We were able to report detection limits of infectious bacteriophage (no bacteriophage was detected by the plaque assay when aerosolised from a suspension of 103 PFU/mL, for three of the four droplet types tested), and that bacteriophage could remain infectious in suspended droplets for up to 20 minutes. We also showed that the nested real-time PCR assay was able to detect the presence of bacteriophage RNA where the plaque assay could not detect any intact particles. Finally, when applying knowledge from the bacteriophage experiments, we reported the quantitative recoveries of influenza viruses in droplets, which were more consistent and stable than we had anticipated. Influenza viruses can be detected up to 20 minutes (after aerosolisation) in suspended aerosols and possibly beyond. It also was detectable from nebulising suspensions with relatively low concentrations of viruses.

Investigation of the expression of the EphB4 receptor tyrosine kinase in prostate carcinoma

Background: The EphB4 receptor tyrosine kinase has been reported as increased in tumours originating from several different tissues and its expression in a prostate cancer xenograft model has been reported. Methods: RT-PCR, western blotting and immunohistochemical techniques were used to examine EphB4 expression and protein levels in human prostate cancer cell lines LNCaP, DU145 and PC3. Immunohistochemistry was also used to examine localisation of EphB4 in tissue samples from 15 patients with prostate carcinomas. Results: All three prostate cancer cell lines expressed the EphB4 gene and protein. EphB4 immunoreactivity in vivo was significantly greater in human prostate cancers as compared with matched normal prostate epithelium and there appeared to be a trend towards increased expression with higher grade disease. Conclusions: EphB4 is expressed in prostate cancer cell lines with increased expression in human prostate cancers when compared with matched normal tissue. EphB4 may therefore be a useful anti-prostate cancer target. © 2005 Lee et al., licensee BioMed Central Ltd.

Opinions, attitudes and driving experiences of car and racing "enthusiasts" : results of the Ontario Car and Racing Club Survey

In recent years, car club and racing websites and forums have become an increasingly popular way for car enthusiasts to access racing and car club news, chat-rooms and message boards. However, no North American research has been found that has examined opinions and driving experiences of car and racing enthusiasts. The purpose of this study was to examine car club members’ opinions about and experiences with various aspects of driving, road safety and traffic legislation, with a particular focus on street racing. A web-based questionnaire (Survey Monkey) was developed using the expert panel method and was primarily based on validated instruments or questions that were developed from other surveys. The questionnaire included: 1) driver concerns regarding traffic safety issues and legislation; 2) attitudes regarding various driving activities; 3) leisure-time activities, including club activities; 4) driving experiences, including offences and collisions; and 5) socio-demographic questions. The survey was pre- tested and piloted. Electronic information letters were sent out to an identified list of car clubs and forums situated in southern Ontario. Car club participants were invited to fill out the questionnaire. This survey found that members of car clubs share similar concerns regarding various road safety issues with samples of Canadian drivers, although a smaller percentage of car club members are concerned about speeding-related driving. Car club members had varied opinions regarding Ontario’s Street Racers, Stunt and Aggressive Drivers Legislation. The respondents agreed the most with the new offences regarding not sitting in the driver’s seat, having a person in the trunk, or driving as close as possible to another vehicle, pedestrian or object on or near the highway without a reason. The majority disagreed with police powers of impoundment and on-the-spot licence suspensions. About three quarters of respondents reported no collisions or police stops for traffic offences in the past five years. Of those who had been stopped, the most common offence was reported as speeding. This study is the first in Canada to examine car club members’ opinions about and experiences with various aspects of driving, road safety and traffic legislation. Given the ubiquity of car clubs and fora in Canada, insights on members’ opinions and practices provide important information to road safety researchers.

Artful interviewing: Conducting oral history interviews for practice-led research

Recently, there has been an increased use of oral history as source material and inspiration for creative products, such as new media productions; visual art; theatre and fiction. The rise of the digital story in museum and library settings reflects a new emphasis on publishing oral histories in forms that are accessible and speak to diverse audiences. Visual artists are embracing oral history as a source of emotional, experiential and thematic authenticity (Anderson 2009 and Brown 2009). Rosemary Neill (2010) observes the rise of documentary and verbatim theatre — where the words of real people are reproduced on-stage — in Australia. Authors such as Dave Eggers (2006), M. J. Hyland (2009), Padma Viswanathan (2008) and Terry Whitebeach (2002) all acknowledge that interviews heavily inform their works of fiction. In such contexts, oral histories are not valued so much for their factual content but as sources that are at once dynamic, evolving, emotionally authentic and ambiguous. How can practice-led researchers design interviews that reflect this emphasis? In this paper, I will discuss how I developed an interview methodology for my own practice-led research project, The Artful Life Story: Oral History and Fiction. In my practice, I draw on oral histories to inform a work of fiction. I developed a methodology for eliciting sensory details and stories around place and the urban environment. I will also read an extract from ‘Evelyn on the Verandah,’ a short story based on an oral history interview with a 21 year-old woman who grew up in New Farm, which will be published in the One Book Many Brisbanes short story anthology in June this year (2010).

Development of zonal cartilage constructs : effects of chondrocyte subpopulation, compressive stimulation, and culture models

Articular cartilage is a highly resilient tissue located at the ends of long bones. It has a zonal structure, which has functional significance in load-bearing. Cartilage does not spontaneously heal itself when damaged, and untreated cartilage lesions or age-related wear often lead to osteoarthritis (OA). OA is a degenerative condition that is highly prevalent, age-associated, and significantly affects patient mobility and quality of life. There is no cure for OA, and patients usually resort to replacing the biological joint with an artificial prosthesis. An alternative approach is to dynamically regenerate damaged or diseased cartilage through cartilage tissue engineering, where cells, materials, and stimuli are combined to form new cartilage. However, despite extensive research, major limitations remain that have prevented the wide-spread application of tissue-engineered cartilage. Critically, there is a dearth of information on whether autologous chondrocytes obtained from OA patients can be used to successfully generate cartilage tissues with structural hierarchy typically found in normal articular cartilage. I aim to address these limitations in this thesis by showing that chondrocyte subpopulations isolated from macroscopically normal areas of the cartilage can be used to engineer stratified cartilage tissues and that compressive loading plays an important role in zone-dependent biosynthesis of these chondrocytes. I first demonstrate that chondrocyte subpopulations from the superficial (S) and middle/deep (MD) zones of OA cartilage are responsive to compressive stimulation in vitro, and that the effect of compression on construct quality is zone-dependent. I also show that compressive stimulation can influence pericelluar matrix production, matrix metalloproteinase secretion, and cytokine expression in zonal chondrocytes in an alginate hydrogel model. Subsequently, I focus on recreating the zonal structure by forming layered constructs using the alginate-released chondrocyte (ARC) method either with or without polymeric scaffolds. Resulting zonal ARC constructs had hyaline morphology, and expressed cartilage matrix molecules such as proteoglycans and collagen type II in both scaffold-free and scaffold-based approaches. Overall, my findings demonstrate that chondrocyte subpopulations obtained from OA joints respond sensitively to compressive stimulation, and are able to form cartilaginous constructs with stratified organization similar to native cartilage using the scaffold-free and scaffold-based ARC technique. The ultimate goal in tissue engineering is to help provide improved treatment options for patients suffering from debilitating conditions such as OA. Further investigations in developing functional cartilage replacement tissues using autologous chondrocytes will bring us a step closer to improving the quality of life for millions of OA patients worldwide.

The artful life story : the oral history interview as fiction

This practice-led PhD project consists of two parts. The first is an exegesis documenting how a fiction writer can enter a dialogue with the oral history project in Australia. I identify two philosophical mandates of the oral history project in Australia that have shaped my creative practice: an emphasis on the analysis of the interviewee’s subjective experience as a means of understanding the past, and the desire to engage a wide audience in order to promote empathy towards the subject. The discussion around fiction in the oral history project is in its infancy. In order to deepen the debate, I draw on the more mature discussion in ethnographic fiction. I rely on literary theorists Steven Greenblatt, Dorrit Cohn and Gerard Genette to develop a clear understanding of the distinct narrative qualities of fiction, in order to explore how fiction can re-present and explore an interviewee’s subjective experience, and engage a wide readership. I document my own methodology for producing a work of fiction that is enriched by oral history methodology and theory, and responds to the mandates of the project. I demonstrate the means by which fiction and the oral history project can enter a dialogue in the truest sense of the word: a two-way conversation that enriches and augments practice in both fields. The second part of the PhD is a novel, set in Brisbane and based on oral history interviews and archival material I gathered over the course of the project. The novel centres on Brisbane artist Evelyn, who has been given an impossible task: a derelict old house is about to be demolished, and she must capture its history in a sculpture that will be built on the site. Evelyn struggles to come up with ideas and create the sculpture, realising that she has no way to discover who inhabited the house. What follows is a series of stories, each set in a different era in Brisbane’s history, which take the reader backwards through the house’s history. Hidden Objects is a novel about the impossibility of grasping the past and the powerful pull of storytelling. The novel is an experiment in a hybrid form and is accompanied by an appendix that identifies the historically accurate sources informing the fiction. The decisions about the aesthetics of the novel were a direct result of my engagement with the mandates of the oral history project in Australia. The novel was shortlisted in the 2012 Queensland Literary Awards, unpublished manuscript category.