Development of Novel Transgenic Zebrafish Models and their Application to Studies on Environmental Oestrogens

Oestrogenic chemicals have become increasingly associated with health effects in wildlife populations and humans. Transgenic animal models have been developed to understand the mechanisms by which these oestrogenic chemicals alter hormonal signalling pathways and how these alterations can lead to chronic health effects. The use of highly informative transgenic animal models will also result in better use and potential reduction of intact animals used in animal testing in line with the principles of the 3Rs. In this thesis work, two novel oestrogen responsive transgenic zebrafish models have been generated to investigate the effects of oestrogenic chemicals, identify their tissue targets and better understand the temporal dynamics of these responses. Both models express the pigment-free ‘Casper’ (a mutant line lacking skin pigment) phenotype, which facilitate identification of responding target tissues in the whole fish in all fish life stages (embryos to adults). The oestrogen response element green fluorescent (ERE-GFP)-Casper model was generated by crossing an established ERE-GFP line with the skin pigment free Casper line. The model generated is highly sensitive to oestrogenic chemicals, detecting responses to environmentally relevant concentrations of EE2, bisphenol A (BPA), genistein and nonylphenol. Use of the ERE-GFP- Casper model shows chemical type and concentration dependence for green fluorescent protein (GFP) induction and both spatial and temporal responses for different environmental oestrogens tested. A semi-automated (ArrayScan) imaging and image analysis system was also developed to quantify whole body fluorescence responses for a range of different oestrogenic chemicals in the new transgenic zebrafish model. The zebrafish model developed provides a sensitive and highly integrative system for identifying oestrogenic chemicals, their target tissues and effect concentrations for exposures in real time and across different life stages. It thus has application for chemical screening to better direct health effects analysis of environmental oestrogens and for investigating the functional roles of oestrogens in vertebrates. The second model generated was an ERE-Kaede-Casper line developed via crossing of the ERE-GFP-Casper line and a UAS-Kaede line and screening subsequent generations for a desired genotype and homozygous expression of the transgenes. Kaede is a photoconvertible fluorescent protein that initially fluoresces green in colour and can be permanently converted to red fluorescence upon short exposure to UV light. The model has a silenced skin pigmentation and high sensitivity to oestrogenic chemicals comparable with the previously developed ERE-GFP-Casper model. Use of this model has identified windows of tissue-specific sensitivity to ethinyloestradiol (EE2) for exposure during early-life (0-48hpf) and illustrated that exposure to oestrogen (EE2) during early life (0-48hpf) can enhance responsiveness (sensitivity) to different environmental oestrogens (EE2, genistein and bisphenol A) for subsequent exposures during development. These findings illustrate the importance of oestrogen exposure history in effects assessments and they have wider implications for the possible adverse effects associated with oestrogen exposure.Biotechnology and Biological Sciences Research Council (BBSRC)AstraZenec

Contribution of Piezo2 to endothelium-dependent pain.

BackgroundWe evaluated the role of a mechanically-gated ion channel, Piezo2, in mechanical stimulation-induced enhancement of hyperalgesia produced by the pronociceptive vasoactive mediator endothelin-1, an innocuous mechanical stimulus-induced enhancement of hyperalgesia that is vascular endothelial cell dependent. We also evaluated its role in a preclinical model of a vascular endothelial cell dependent painful peripheral neuropathy.ResultsThe local administration of oligodeoxynucleotides antisense to Piezo2 mRNA, at the site of nociceptive testing in the rat's hind paw, but not intrathecally at the central terminal of the nociceptor, prevented innocuous stimulus-induced enhancement of hyperalgesia produced by endothelin-1 (100 ng). The mechanical hyperalgesia induced by oxaliplatin (2 mg/kg. i.v.), which was inhibited by impairing endothelial cell function, was similarly attenuated by local injection of the Piezo2 antisense. Polymerase chain reaction analysis demonstrated for the first time the presence of Piezo2 mRNA in endothelial cells.ConclusionsThese results support the hypothesis that Piezo2 is a mechano-transducer in the endothelial cell where it contributes to stimulus-dependent hyperalgesia, and a model of chemotherapy-induced painful peripheral neuropathy

How do firm's use cash tax savings? A cross-country analysis

Avoiding cash taxes can serve as a significant source of additional cash flows for firms, though how managers utilize these funds and the resulting consequences remain open empirical questions. We provide answers by examining the association between the amount of cash tax savings and two uses of cash – investment and dividend payout – for an international sample of firms. We find that firms are more likely to invest cash tax savings rather than distribute them in the form of dividends and that this results in inefficient overinvestment. We find that our results hold for an international sample of domestic-only sample, distinguishing our study from US-only studies, which focus on constraints and distortions of multi-national corporations in a worldwide tax system. We find nuanced results when partitioning on country-level governance. Our results suggest cash tax avoidance has real effects on firm decisions, namely investment and payout policies, and this effect varies based on the country in which the firm operates

Beyond normal competencies: understanding organisation designs to develop and sustain IT-related capabilities

Information technology (IT) is an important resource in organisations. Organisations leverage their IT resources with their IT-related capabilities to achieve, and sustain their competitive position. However, IT resources are dynamic, and evolve continually. Furthermore, competitive pressures and turbulent economic conditions mean that organisations continually invest in these dynamic IT resources. These situations mean that organisations need to sustain their IT-related competencies to leverage opportunities offered by the new IT resources. Research about ways to develop new, and sustain existing, IT-related capabilities is limited. A possible reason for the lack of research in this area is the lack of validated measurement items of theoretical constructs necessary to investigate ways to create new, and sustain, existing, IT-related competencies and capabilities. In this study, we suggest an environment in which organisations could build new, and sustain their existing IT-related capabilities. We report on the resources and processes that establish this environment. We also report on the development of valid measures of the elements of this environment. Analysis of pilot test data revealed that the measurement items purport to measure what they intended to measure. This study's outcome is useful in extending our understanding of IT-related competence development to secure sustainable IT-related business value from the IT resources

Biology-specific vocabulary: students’ understanding and lecturers’ expectations of student understanding

The current A-level biology curriculum includes a broad coverage of all the biosciences which demands knowledge of a wide range of biological vocabulary. Students (n = 184) from two UK universities were presented with a list of vocabulary, associated with a ‘Revise Biology’ text which highlighted key terms that students should know. Lecturers (n = 26) were asked which of these terms they expected students to know, or be aware of. Findings revealed that students’ claimed knowledge of vocabulary exceeded lecturer expectations. In addition, there were a number of terms which students did not understand and lecturers did not expect them to know, which could be removed from A-level biology courses. This is discussed in relation to whether A-level curricula need to be so content heavy and whether lecturers would benefit from knowing more about their students’ knowledge of discipline-specific terms

Biology-specific vocabulary: students’ understanding and lecturers’ expectations of student understanding

The current A-level biology curriculum includes a broad coverage of all the biosciences which demands knowledge of a wide range of biological vocabulary. Students (n = 184) from two UK universities were presented with a list of vocabulary, associated with a ‘Revise Biology’ text which highlighted key terms that students should know. Lecturers (n = 26) were asked which of these terms they expected students to know, or be aware of. Findings revealed that students’ claimed knowledge of vocabulary exceeded lecturer expectations. In addition, there were a number of terms which students did not understand and lecturers did not expect them to know, which could be removed from A-level biology courses. This is discussed in relation to whether A-level curricula need to be so content heavy and whether lecturers would benefit from knowing more about their students’ knowledge of discipline-specific terms

On Cloud Computing Service Considerations for the Small and Medium Enterprises

The concept of cloud computing services is appealing to the small and medium enterprises (SMEs), with the opportunity to acquire modern information technology resources as a utility and avoid costly capital investments in technology resources. However, the adoption of the cloud computing services presents significant challenges to the SMEs. The SMEs need to determine a path to adopting the cloud computing services that would ensure their sustainable presence in the cloud computing environment. Information about approaches to adopting the cloud computing services by the SMEs is fragmented. Through an interpretive design, we suggest that the SMEs need to have a strategic and incremental intent, understand their organizational structure, understand the external factors, consider the human resource capacity, and understand the value expectations from the cloud computing services to forge a successful path to adopting the cloud computing services. These factors would contribute to a model of cloud services for SMEs

Towards an Effective Structure of IT Governance for Organizations in Developing Economies.

The pervasive use of IT is prominent amongst organizations in developing economies. However, there is growing evidence that these economies fail to capitalize on their IT investment to transform their organizations to be competitive both locally and globally. IT-related benefits are possible with appropriate governance of the IT-related resources, and we need to broaden our understanding on the IT governance mechanics suitable for organizations in the developing economies. In this study, we adopted an initial interpretive design to obtain a deeper understanding of the IT governance (ITG) environment and conceptions of the stakeholders on effective IT governance structures for the developing economies. We found that the presence of an IT Strategic Planning Committee, Multiple level of authority, and a Forum for informal discussions as the crucial components of an ITG structure in developing economies

Mainstream News Articles Co-Shared with Fake News Buttress Misinformation Narratives

Most prior and current research examining misinformation spread on social media focuses on reports published by 'fake' news sources. These approaches fail to capture another potential form of misinformation with a much larger audience: factual news from mainstream sources ('real' news) repurposed to promote false or misleading narratives. We operationalize narratives using an existing unsupervised NLP technique and examine the narratives present in misinformation content. We find that certain articles from reliable outlets are shared by a disproportionate number of users who also shared fake news on Twitter. We consider these 'real' news articles to be co-shared with fake news. We show that co-shared articles contain existing misinformation narratives at a significantly higher rate than articles from the same reliable outlets that are not co-shared with fake news. This holds true even when articles are chosen following strict criteria of reliability for the outlets and after accounting for the alternative explanation of partisan curation of articles. For example, we observe that a recent article published by The Washington Post titled "Vaccinated people now make up a majority of COVID deaths" was disproportionately shared by Twitter users with a history of sharing anti-vaccine false news reports. Our findings suggest a strategic repurposing of mainstream news by conveyors of misinformation as a way to enhance the reach and persuasiveness of misleading narratives. We also conduct a comprehensive case study to help highlight how such repurposing can happen on Twitter as a consequence of the inclusion of particular narratives in the framing of mainstream news