190 resultados para Pryor, Roger A. (Roger Atkinson), 1828-1919.
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MicroRNAs (miRNAs) are a class of small non-coding RNAs with a critical role in development and environmental responses. Efficient and reliable detection of miRNAs is an essential step towards understanding their roles in specific cells and tissues. However, gel-based assays currently used to detect miRNAs are very limited in terms of throughput, sensitivity and specificity. Here we provide protocols for detection and quantification of miRNAs by RT-PCR. We describe an end-point and real-time looped RT-PCR procedure and demonstrate detection of miRNAs from as little as 20 pg of plant tissue total RNA and from total RNA isolated from as little as 0.1 l of phloem sap. In addition, we have developed an alternative real-time PCR assay that can further improve specificity when detecting low abundant miRNAs. Using this assay, we have demonstrated that miRNAs are differentially expressed in the phloem sap and the surrounding vascular tissue. This method enables fast, sensitive and specific miRNA expression profiling and is suitable for facilitation of high-throughput detection and quantification of miRNA expression.
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High-temperature, low-light (HTLL) treatment of 35S:PAP1 Arabidopsis thaliana over-expressing the PAP1 (Production of Anthocyanin Pigment 1) gene results in reversible reduction of red colouration, suggesting the action of additional anthocyanin regulators. High-performance liquid chromatography (HPLC), liquid chromatography mass spectrometry (LCMS) and Affimetrix®-based microarrays were used to measure changes in anthocyanin, flavonoids, and gene expression in response to HTLL. HTLL treatment of control and 35S:PAP1 A. thaliana resulted in a reversible reduction in the concentrations of major anthocyanins despite ongoing over-expression of the PAP1 MYB transcription factor. Twenty-one anthocyanins including eight cis-coumaryl esters were identified by LCMS. The concentrations of nine anthocyanins were reduced and those of three were increased, consistent with a sequential process of anthocyanin degradation. Analysis of gene expression showed down-regulation of flavonol and anthocyanin biosynthesis and of transport-related genes within 24 h of HTLL treatment. No catabolic genes up-regulated by HTLL were found. Reductions in the concentrations of anthocyanins and down-regulation of the genes of anthocyanin biosynthesis were achieved by environmental manipulation, despite ongoing over-expression of PAP1. Quantitative PCR showed reduced expression of three genes (TT8, TTG1 and EGL3) of the PAP1 transcriptional complex, and increased expression of the potential transcriptional repressors AtMYB3, AtMYB6 and AtMYBL2 coincided with HTLL-induced down-regulation of anthocyanin biosynthesis. HTLL treatment offers a model system with which to explore anthocyanin catabolism and to discover novel genes involved in the environmental control of anthocyanins.
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Proanthocyanidins (PAs) are products of the flavonoid pathway, which also leads to the production of anthocyanins and flavonols. Many flavonoids have antioxidant properties and may have beneficial effects for human health. PAs are found in the seeds and fruits of many plants. In apple fruit (Malus × domestica Borkh.), the flavonoid biosynthetic pathway is most active in the skin, with the flavan-3-ols, catechin, and epicatechin acting as the initiating units for the synthesis of PA polymers. This study examined the genes involved in the production of PAs in three apple cultivars: two heritage apple cultivars, Hetlina and Devonshire Quarrenden, and a commercial cultivar, Royal Gala. HPLC analysis shows that tree-ripe fruit from Hetlina and Devonshire Quarrenden had a higher phenolic content than Royal Gala. Epicatechin and catechin biosynthesis is under the control of the biosynthetic enzymes anthocyanidin reductase (ANR) and leucoanthocyanidin reductase (LAR1), respectively. Counter-intuitively, real-time quantitative PCR analysis showed that the expression levels of Royal Gala LAR1 and ANR were significantly higher than those of both Devonshire Quarrenden and Hetlina. This suggests that a compensatory feedback mechanism may be active, whereby low concentrations of PAs may induce higher expression of gene transcripts. Further investigation is required into the regulation of these key enzymes in apple.
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The composition of carotenoids, along with anthocyanins and chlorophyll, accounts for the distinctive range of colour found in the Actinidia (kiwifruit) species. Lutein and beta-carotene are the most abundant carotenoids found during fruit development, with beta-carotene concentration increasing rapidly during fruit maturation and ripening. In addition, the accumulation of beta-carotene and lutein is influenced by the temperature at which harvested fruit are stored. Expression analysis of carotenoid biosynthetic genes among different genotypes and fruit developmental stages identified Actinidia lycopene beta-cyclase (LCY-β) as the gene whose expression pattern appeared to be associated with both total carotenoid and beta-carotene accumulation. Phytoene desaturase (PDS) expression was the least variable among the different genotypes, while zeta carotene desaturase (ZDS), beta-carotene hydroxylase (CRH-β), and epsilon carotene hydroxylase (CRH-ε) showed some variation in gene expression. The LCY-β gene was functionally tested in bacteria and shown to convert lycopene and delta-carotene to beta-carotene and alpha-carotene respectively. This indicates that the accumulation of beta-carotene, the major carotenoid in these kiwifruit species, appears to be controlled by the level of expression of LCY-β gene.
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Background Sexually-transmitted pathogens often have severe reproductive health implications if treatment is delayed or absent, especially in females. The complex processes of disease progression, namely replication and ascension of the infection through the genital tract, span both extracellular and intracellular physiological scales, and in females can vary over the distinct phases of the menstrual cycle. The complexity of these processes, coupled with the common impossibility of obtaining comprehensive and sequential clinical data from individual human patients, makes mathematical and computational modelling valuable tools in developing our understanding of the infection, with a view to identifying new interventions. While many within-host models of sexually-transmitted infections (STIs) are available in existing literature, these models are difficult to deploy in clinical/experimental settings since simulations often require complex computational approaches. Results We present STI-GMaS (Sexually-Transmitted Infections – Graphical Modelling and Simulation), an environment for simulation of STI models, with a view to stimulating the uptake of these models within the laboratory or clinic. The software currently focuses upon the representative case-study of Chlamydia trachomatis, the most common sexually-transmitted bacterial pathogen of humans. Here, we demonstrate the use of a hybrid PDE–cellular automata model for simulation of a hypothetical Chlamydia vaccination, demonstrating the effect of a vaccine-induced antibody in preventing the infection from ascending to above the cervix. This example illustrates the ease with which existing models can be adapted to describe new studies, and its careful parameterisation within STI-GMaS facilitates future tuning to experimental data as they arise. Conclusions STI-GMaS represents the first software designed explicitly for in-silico simulation of STI models by non-theoreticians, thus presenting a novel route to bridging the gap between computational and clinical/experimental disciplines. With the propensity for model reuse and extension, there is much scope within STI-GMaS to allow clinical and experimental studies to inform model inputs and drive future model development. Many of the modelling paradigms and software design principles deployed to date transfer readily to other STIs, both bacterial and viral; forthcoming releases of STI-GMaS will extend the software to incorporate a more diverse range of infections.
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SVP-like MADS domain transcription factors have been shown to regulate flowering time and both inflorescence and flower development in annual plants, while having effects on growth cessation and terminal bud formation in perennial species. Previously, four SVP genes were described in woody perennial vine kiwifruit (Actinidia spp.), with possible distinct roles in bud dormancy and flowering. Kiwifruit SVP3 transcript was confined to vegetative tissues and acted as a repressor of flowering as it was able to rescue the Arabidopsis svp41 mutant. To characterize kiwifruit SVP3 further, ectopic expression in kiwifruit species was performed. Ectopic expression of SVP3 in A. deliciosa did not affect general plant growth or the duration of endodormancy. Ectopic expression of SVP3 in A. eriantha also resulted in plants with normal vegetative growth, bud break, and flowering time. However, significantly prolonged and abnormal flower, fruit, and seed development were observed, arising from SVP3 interactions with kiwifruit floral homeotic MADS-domain proteins. Petal pigmentation was reduced as a result of SVP3-mediated interference with transcription of the kiwifruit flower tissue-specific R2R3 MYB regulator, MYB110a, and the gene encoding the key anthocyanin biosynthetic step, F3GT1. Constitutive expression of SVP3 had a similar impact on reproductive development in transgenic tobacco. The flowering time was not affected in day-neutral and photoperiod-responsive Nicotiana tabacum cultivars, but anthesis and seed germination were significantly delayed. The accumulation of anthocyanin in petals was reduced and the same underlying mechanism of R2R3 MYB NtAN2 transcript reduction was demonstrated.
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This paper aims to review the notion of the one-stop shop, particularly as it has developed in Australia. It has three main components. The first focuses on a significant initiative taken by the Coombs Royal Commission on Australian Government Administration as a form of action research in the mid-1970s. The second highlights the associated work on access theory by the late Bernard Schaffer and his associates and explains why this work was of fundamental importance for the development of the idea of the one-stop shop. The third deals with subsequent Australian understandings and a pp lications of the idea.
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In increasingly competitive labour markets, attracting and retaining talent has become a prime concern of organisations. Employers need to understand the range of factors that influence career decision making and the role of employer branding in attracting human capital that best fits and contributes to the strategic aims of an organisation. This chapter identifies the changing factors that attract people to certain employment and industries and discusses the importance of aligning employer branding with employee branding to create a strong, genuine and lasting employer brand. Whilst organisations have long used marketing and branding practices to engender loyalty in customers, they are increasingly expanding this activity to differentiate organisations and make them attractive from an employee perspective. This chapter discusses employer branding and industry image as two important components of attraction strategies and describes ways companies can maximise their brand awareness in the employment market to both current and future employees.
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It is well established that the coordinated regulation of activity-dependent gene expression by the histone acetyltransferase (HAT) family of transcriptional coactivators is crucial for the formation of contextual fear and spatial memory, and for hippocampal synaptic plasticity. However, no studies have examined the role of this epigenetic mechanism within the infralimbic prefrontal cortex (ILPFC), an area of the brain that is essential for the formation and consolidation of fear extinction memory. Here we report that a postextinction training infusion of a combined p300/CBP inhibitor (Lys-CoA-Tat), directly into the ILPFC, enhances fear extinction memory in mice. Our results also demonstrate that the HAT p300 is highly expressed within pyramidal neurons of the ILPFC and that the small-molecule p300-specific inhibitor (C646) infused into the ILPFC immediately after weak extinction training enhances the consolidation of fear extinction memory. C646 infused 6 h after extinction had no effect on fear extinction memory, nor did an immediate postextinction training infusion into the prelimbic prefrontal cortex. Consistent with the behavioral findings, inhibition of p300 activity within the ILPFC facilitated long-term potentiation (LTP) under stimulation conditions that do not evoke long-lasting LTP. These data suggest that one function of p300 activity within the ILPFC is to constrain synaptic plasticity, and that a reduction in the function of this HAT is required for the formation of fear extinction memory.
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"Every year deliberately lit fires rage across Indonesia. They destroy pristine rainforest, endanger orangutans and contribute to climate change. A young carbon trading entrepreneur goes in search of a solution." "Dorjee Sun, a young Australian Entrepreneur, believes there's money to be made from protecting rainforests in Indonesia, saving the orangutan from extinction and making a real impact on climate change. Armed with a laptop and a backpack, he sets out across the globe to find investors in his carbon trading scheme. It is a battle against time. Achmadi, the palm oil farmer is ready to set fire to his land to plant more palm oil, and Lone's orangutan centre has reached crisis point with over 600 orangutans rescued from the fires. The Burning Season is an eco-thriller about a young man not afraid to confront the biggest challenge of our time."
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Chapters in Book 1 of this two-volume set explored literature pertaining to the shortage of engineers in Australia, the ageing engineering workforce, issues of skilled migration, and career development and pathways. The companion chapter to this one in Book 1 explored attraction and image issues of certain industries that required a pipeline of engineers. This chapter will reflect on our research with final-year engineering students in Australian universities and TAFE colleges regarding their career aspirations, industries and/or organisations that they identify as attractive employers, and their perceptions of a low-profile industry, namely the Australian rail industry. This chapter will also discuss specific, evidence-based strategies and activities to enhance the image and attraction of low-profile industries.
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Zein was investigated for use as an oral-drug delivery system by loading prednisolone into zein microparticles using coacervation. To investigate the adaptability of this method to other drugs, zein microparticles were loaded with hydrocortisone, which is structurally related to prednisolone; or mesalazine, which is structurally different having a smaller LogP and ionizable functional groups. Investigations into the in vitro digestibility, and the electrophoretic profile of zein, and zein microparticles were conducted to shed further insight on using this protein as a drug delivery system. Hydrocortisone loading into zein microparticles was comparable with that reported for prednisolone, but mesalazine loading was highly variable. Depending on the starting quantities of hydrocortisone and zein, the average amount of microparticles equivalent to 4 mg hydrocortisone, (a clinically used dose), ranged from 60-115 mg, which is realistic and practical for oral dosing. Comparatively, an average of 2.5 g of microparticles was required to deliver 250 mg of mesalazine (a clinically used dose), so alternate encapsulation methods that can produce higher and more precise mesalazine loading are required. In vitro protein digestibility revealed that zein microparticles were more resistant to digestion compared to the zein raw material, and that individual zein peptides are not preferentially coacervated into the microparticles. In combination, these results suggest that there is potential to formulate a delivery system based on zein microparticles made using specific subunits of zein that is more resistant to digestion as starting material, to deliver drugs to the lower gastrointestinal tract.
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This chapter examines lessons learnt from a study of the use of e-learning within the rail sector in Australia and explores factors that inhibit or advance its organisational effectiveness. We examine the social, organisational and technical influences on the way employees perceive and use e-learning. By examining these issues, we aim to demonstrate that successful organisational adoption of e-learning is influenced by factors beyond the systems themselves and requires a more holistic understanding of the target workforce and the suitability of the e-learning tasks. Without a clear understanding of these relationships, organisations run the real risk of investing heavily in e-learning without receiving benefits or, worse still, impacting negatively on their ability to deliver training.
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The successful management of workplace safety has many benefits for employees, employers and the community. Similar to other areas of job performance, safety performance can be enhanced through appropriate and well-designed training. The foundation of the development of effective training is a thorough training needs analysis (TNA). Currently, the application of psychometrically valid TNA practices for the management of workplace safety is an under-researched topic and limited guidance is available for implementing appropriate strategies. To address this gap in the literature, this chapter will provide an overview of TNA practices, including the purpose and benefits associated with implementing the systematic procedure. A case study will then be presented to illustrate how the TNA process was successfully applied to investigate the training needs of Australasian rail incident investigators to achieve an industry-approved national training package. Recommendations will be made to assist practitioners with implementing TNA practices with the goal of enhancing workplace safety management through targeted workforce development.
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Whilst inclusive education is a relatively recent advance in our thinking about schooling and pedagogy, it is rapidly establishing movement simultaneously reflected in and refracted by education policy, research, and scholarship. This is manifest in the proliferation of policy texts and programmes generated by education jurisdictions globally and locally, and in the burgeoning number of scholarly texts, academic conferences, and research grants dedicated to inclusive education.