296 research outputs found

    Investigating the impact of polymicrobial interactions on fungal pathogenicity

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    Within the human body, microorganisms reside as part of a complex and varied ecosystem, where they rarely exist in isolation. Bacteria and fungi have co-evolved to develop elaborate and intricate relationships, utilising both physical and chemical communication mechanisms. Mucorales are filamentous fungi that are the causative agents of mucormycosis in immunocompromised individuals. Key to the pathogenesis is the ability to germinate and penetrate the surrounding tissues, leading to angioinvasion, vessel thrombosis, and tissue necrosis. It is currently unknown whether Mucorales participate in polymicrobial relationships, and if so, how this affects the pathogenesis. This project analyses the relationship between Mucorales and the microorganisms they may encounter. Here we show that Pseudomonas aeruginosa culture supernatants and live bacteria inhibit Rhizopus microsporus germination through the sequestration of iron. Therefore, treatment of P. aeruginosa in a patient could result in the release of this inhibition, leaving the patient more susceptible to an underlying fungal infection. However, P. aeruginosa responds to the presence of R. microsporus by enhancing siderophore production, which increases host mortality in a zebrafish co-infection model. This project highlights the complex competition between these organisms and the possible enhanced disease pathology when R. microsporus and P. aeruginosa meet in a host

    A proposed roadmap for the control of infections in wildlife using Chlamydia vaccine development in koalas Phascolarctos cinereus as a template

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    Vaccination strategies provide a crucial tool for managements of disease risks in wildlife, but have been utilized mostly for domestic species. However, a significant body of work has now been published describing the successful development of an anti-chlamydial vaccine for the koala Phascolarctos cinereus, Goldfuss, 1817. As such, vaccinations against these infections in the koala, can provide important insights into the use of vaccines for wildlife. Chlamydia infections in the koala have been intensively studied for over 30 years. Infections cause severe disease states, such as kerato-conjunctivitis (blindness) and reproductive tract disease (infertility), and/or mortality; and are contributing significantly to population declines. We aim to use the plethora of data available from koala chlamydial studies as a template to propose a roadmap for the development of vaccines for other wildlife species, especially in this era of antibiotic resistance. As such we have outlined the important steps that have led to significant milestones resulting in the successful development of a vaccine against an infectious disease in a non-domestic species. We hope to thus provide, not only a timely review on Chlamydia vaccines in koalas, but also an important conservation and management roadmap to help guide future researchers that are considering the development of a vaccine for a wild species.publishedVersio

    Environmental pollutants modulate RNA and DNA virus-activated miRNA-155 expression and innate immune system responses: Insights into new immunomodulative mechanisms

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    Many persistent organic pollutants, such as polychlorinated biphenyls (PCBs), have high immunomodulating potentials. Exposure to them, in combination with virus infections, has been shown to aggravate outcomes of the infection, leading to increased viral titers and host mortality. Expression of immune-related microRNA (miR) signaling pathways (by host and/or virus) have been shown to be important in determining these outcomes; there is some evidence to suggest pollutants can cause dysregulation of miRNAs. It was thus hypothesized here that modulation of miRNAs (and associated cytokine genes) by pollutants exerts negative effects during viral infections. To test this, an in vitro study on chicken embryo fibroblasts (CEF) exposed to a PCB mixture (Aroclor 1260) and then stimulated with a synthetic RNA virus (poly(I:C)) or infected with a lymphoma-causing DNA virus (Gallid Herpes Virus 2 [GaHV-2]) was conducted. Using quantitative real-time PCR, expression patterns for mir-155, pro-inflammatory TNFα and IL-8, transcription factor NF-κB1, and anti-inflammatory IL-4 were investigated 8, 12, and 18 h after virus activation. The study showed that Aroclor1260 modulated mir-155 expression, such that a down-regulation of mir-155 in poly(I:C)-treated CEF was seen up to 12 h. Aroclor1260 exposure also increased the mRNA expression of pro-inflammatory genes after 8 h in poly(I:C)-treated cells, but levels in GaHV-2-infected cells were unaffected. In contrast to with Aroclor1260/poly(I:C), Aroclor1260/GaHV-2-infected cells displayed an increase in mir-155 levels after 12 h compared to levels seen with either individual treatment. While after 12 h expression of most evaluated genes was down-regulated (independent of treatment regimen), by 18 h, up-regulation was evident again. In conclusion, this study added evidence that mir-155 signaling represents a sensitive pathway to chemically-induced immunomodulation and indicated that PCBs can modulate highly-regulated innate immune system signaling pathways important in determining host immune response outcomes during viral infections.publishedVersio

    Art-ificial: The Philosophy of AI Art

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    This thesis aims to contribute to a novel area of philosophical work: the philosophy of AI art. AI art is proliferating online and increasingly in the world of art. The growing presence of works made by (or with) artificial intelligence has led to a clamour of questions such as 'Is AI art really art?' and 'can AI be truly creative?'. As yet, these questions have barely been tackled in the philosophical literature, especially in aesthetics. This thesis aims to address this gap. This thesis starts by establishing what we mean by 'AI art' by examining examples of AI works and the technological underpinnings of these systems. Existing work on the topic of AI art is explicated. In particular, Mark Coeckelbergh's three questions on AI art scaffold the first three chapters of the thesis: 'can machines create art?', 'can machines create art?' and 'can machines create art?' Chapter 1 aims to answer the question of whether AI can make art through the evaluation of AI works against three definitions of art: the institutional account, the historical account, and the cluster account. Chapter 2 focusses on the question of whether AI can be creative. Three accounts of creativity are utilised: a Darwinian theory of creativity, Margaret Boden's account of creativity, and Berys Gaut's agential account of creativity. It is argued that some AI systems can meet the requirements of each of these, aside from Gaut's necessary criterion of agency. After chapters 1 and 2, questions about the limitations of AI systems in meeting the requirements of different accounts of art and creativity remain; chapter 3 aims to address some of these. The possibility of AI (extended) mind is investigated, followed by AI embodiment. Finally, an argument for the possibility of AI agency is put forward. This minimal account of agency allows for the possibility of AI creativity under the agential account. The latter part of this thesis begins with chapter 4, which examines the possibility that AI systems will not share aesthetic or artistic values with humans, and whether this is cause for concern. Finally, Chapter 5 examines two qualities of AI images: weirdness and convincingness, showing that AI art can offer interesting aesthetic qualities worthy of investigation. Through this thesis, I put forward a first step in developing a philosophy of AI art

    Patterns of prefrontal dysfunction in alcoholics with and without Korsakoff’s syndrome, patients with Parkinson’s disease, and patients with rupture and repair of the anterior communicating artery

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    This study compared patterns of frontal-lobe dysfunction in alcoholics with Korsakoff’s syndrome (KS: n = 9), non-Korsakoff alcoholics (AL: n = 28), patients with Parkinson’s disease (PD: n = 18), and patients with rupture and repair of the anterior communicating artery (ACoA: n = 4) relative to healthy non-neurological control (NC) participants (n = 70). The tests administered were sensitive to functions of dorsolateral prefrontal and orbito-frontal subsystems. Measures included perseverative errors on the Wisconsin Card Sorting Test (WCST-pe), errors on object alternation (OA), errors on Trails B, number of words generated on the Controlled Oral Word Association Test (COWAT), and number of categories completed on the WCST (WCST-cc). KS patients were as impaired as AL participants on orbitofrontal measures and, on dorsolateral prefrontal measures, were impaired relative to AL participants, whose performance did not differ from controls. Patients with PD also were impaired on tests of orbitofrontal and dorsolateral prefrontal functioning but to a lesser extent than the KS patients. Moreover, most of the PD deficits were driven by the impaired performance of patients whose initial symptoms were on the right side of the body. The ACoA patients were significantly impaired on tests of orbitofrontal but not dorsolateral prefrontal functioning relative to the control group. Together, the results confirm different patterns of frontal-system impairments in patient groups having compromised frontal lobe functioning consequent to varying etiologies

    “A Pesar de las Fronteras”/“In Spite of the Boundaries” : Exploring Solidarity in the Context of International Service Immersion

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    The move to “internationalize” United States universities has contrib-uted to increased interest in global service-learning. This article presents qualitative data collected by a team of faculty and students during a ser-vice immersion in Nicaragua. The solidarity model of service-learning attempts to address shortcomings of earlier approaches and deserves fur-ther examination. This study illuminated the dynamics of solidarity from a largely unexplored perspective: host families and community leaders. The analysis revealed that difference and inequality are salient themes and shape the relationships and possibilities for joint action between U.S. students and their hosts. A typology is suggested that includes symbolic, instrumental, and pragmatic performances of solidarity. By highlighting the perspective of Nicaraguan hosts, this study fills an important gap in the literature on service-learning. It also contributes to the conceptual elaboration of an often heard but rarely defined concept: solidarity

    We Will Rise No Matter What\u27: Community Perspectives of Disaster Resilience Following Hurricanes Irma and Maria In Puerto Rico

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    Category 4 Hurricane Maria made landfall in Puerto Rico on 20 September 2017 and ploughed across the territory with sustained winds of 155 mph. Just two weeks earlier, category 5 Hurricane Irma had struck the island already damaging critical infrastructure making Hurricane Maria even more devasting. The hurricanes caused catastrophic damage, resulting in the largest and longest response to a domestic disaster in the history of the United States. This paper explores the recovery process in Puerto Rico using a community resilience lens. The study examines narratives, the media environment, trusted sources, and information preferences following the crisis. Community workshops, interviews, and focus groups reveal indicators of resilience in Puerto Rico alongside areas for improvement. Theoretical contributions discuss the role of identity, sense of place, and the impact of culture on community resilience. Practical contributions touch on messaging, acknowledging infrastructure vulnerabilities, and the importance of strengthening community relationships

    Impact of Weight of the Nation Community Screenings on Obesity-Related Beliefs

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    HBO’s Weight of the Nation was a collaborative effort among several national organizations to raise awareness about the complexity of the obesity epidemic and promote action through media and community forums. The primary aim of this study was to assess the short-term effects of Weight of the Nation community screenings on obesity-related beliefs, intentions, and policy support

    Interannual variability in the lipid and fatty acid profiles of east Australia-migrating humpback whales (Megaptera novaeangliae) across a 10-year timeline

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    Southern hemisphere humpback whales are classified as high-fidelity Antarctic krill consumers and as such are vulnerable to variability and long-term changes in krill biomass. Evidence of heterogeneous feeding patterns of east coast of Australia migrating humpback whales has been observed, warranting a comprehensive assessment of interannual variability in their diet. We examined the lipid and fatty acid profiles of individuals of the east coast of Australia migrating stock sampled between 2008 and 2018. The use of live-sampled blubber biopsies showed that fatty acid profiles varied significantly among all years. The two trophic indicator fatty acids for Antarctic krill, 20:5ω3 and 22:6ω3 remained largely unchanged across the 10-year period, suggesting that Antarctic krill is the principal prey item. A distance-based linear model showed that 33% of the total variation in fatty acid profiles was explained by environmental variables and climate indices. Most of the variation was explained by the Southern Annular Mode (23.7%). The high degree of variability observed in this study was unexpected for a species that is thought to feed primarily on one prey item. We propose that the observed variability likely arises from changes in the diet of Antarctic krill rather than changes in the whale’s diet.publishedVersio
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