1,736 research outputs found
Variation in siderophore biosynthetic gene distribution and production across environmental and faecal populations of Escherichia coli.
No full textIron is essential for Escherichia coli growth and survival in the host and the external environment, but its availability is generally low due to the poor solubility of its ferric form in aqueous environments and the presence of iron-withholding proteins in the host. Most E. coli can increase access to iron by excreting siderophores such as enterobactin, which have a very strong affinity for Fe3+. A smaller proportion of isolates can generate up to 3 additional siderophores linked with pathogenesis; aerobactin, salmochelin, and yersiniabactin. However, non-pathogenic E. coli are also able to synthesise these virulence-associated siderophores. This raises questions about their role in the ecology of E. coli, beyond virulence, and whether specific siderophores might be linked with persistence in the external environment. Under the assumption that selection favours phenotypes that confer a fitness advantage, we compared siderophore production and gene distribution in E. coli isolated either from agricultural plants or the faeces of healthy mammals. This population-level comparison has revealed that under iron limiting growth conditions plant-associated isolates produced lower amounts of siderophores than faecal isolates. Additionally, multiplex PCR showed that environmental isolates were less likely to contain loci associated with aerobactin and yersiniabactin synthesis. Although aerobactin was linked with strong siderophore excretion, a significant difference in production was still observed between plant and faecal isolates when the analysis was restricted to strains only able to synthesise enterobactin. This finding suggests that the regulatory response to iron limitation may be an important trait associated with adaptation to the non-host environment. Our findings are consistent with the hypothesis that the ability to produce multiple siderophores facilitates E. coli gut colonisation and plays an important role in E. coli commensalism
Writing and the rights of reality: usurpation and potentiality in Derrida, Plato, Nietzsche, and Beckett
No full textThe thesis critically evaluates Jacques Derrida's conferral of the rights of reality on writing, focussing on his theory of an arche-text in light of the speculative nature of this theory. The theory is initially considered in the context of Derrida's elucidation of the usurpatory status of writing within the Platonic and Nietzschean texts. This consideration reveals an admission of writing's usurpatory status by both writers while at the same time demonstrating their awareness of the intrinsically speculative nature of this view, the significance of writing lying in its ability to exteriorise the radically indeterminate status of consciousness m relation to reality rather than its ability to displace consciousness or reality The analyses, therefore, not only bring the Derridean hypothesis of a repressive or phonocentric metaphysical episteme into question but also exhibit the historical and philosophical role of potentiality in relation to writing, writing's ultimate significance lying in its capacity to exteriorise our existence as a mode of potentiality. Accordingly, in the second half of the thesis the Derridean theory of writing is countered with a specifically Aristotelian theory of the text as it is exhibited in the prose of Samuel Beckett, an author whose significance lies in his close alignment with Derridean theory within contemporary criticism. It is demonstrated that this identification has obviated an awareness of the significance of potentiality within the Beckettian text, his work consequently being appraised in the previously neglected context of Aristotelian metaphysics
Richardson, Barbauld, and the construction of an early modern fan club
No full textMPhilMuch has been written about the life and long works of the eighteenth century epistolary novelist, Samuel Richardson, but the prospect of his position as the first celebrity novelist – responsible for courting his own fame as well as initiating his own fan club – has largely been ignored. The body of manuscripts housed at the National Art Library in the Victoria and Albert Museum in London provides the modern scholar with evidence of the skeletal beginnings of an early fan club. This thesis aims to show how these manuscripts were turned into a saleable commodity by the publisher and entrepreneur Richard Phillips, while under the guiding hand of another, slightly later, literary celebrity, Anna Laetitia Barbauld. In order to restore Richardson’s reputation amongst a new nineteenth century audience, Barbauld was required to construct her own idea of him as an eighteenth century celebrity author, and in doing so the insecurities of a self-professed, apparently diffident man, are revealed. Barbauld’s capacious, but heavily edited selection of letters is analyzed in this thesis, providing ample evidence that Richardson’s correspondents were more than just eager letter writers. By using Barbauld’s biography of Richardson this thesis aims to show how she manipulates the genre of life writing in her construction of him.
This thesis offers an alternative reading of how the Richardson manuscripts are viewed, redefining them as not simply a collection of letters, but as a collective entity, deliberately selected and archived as evidence of an early modern fan club, and its celebrity managing director
Usability and acceptability of a website that provides tailored advice on falls prevention activities for older people
No full textThis article presents the usability and acceptability of a website that provides older people with tailored advice to help motivate them to undertake physical activities that prevent falls. Views on the website from interviews with 16 older people and 26 sheltered housing wardens were analysed thematically. The website was well received with only one usability difficulty with the action plan calendar. The older people selected balance training activities out of interest or enjoyment, and appeared to carefully add them into their current routine. The wardens were motivated to promote the website to their residents, particularly those who owned a computer, had balance problems, or were physically active. However, the participants noted that currently a minority of older people use the Internet. Also, some older people underestimated how much activity was enough to improve balance, and others perceived themselves as too old for the activities
Neoarchean continental growth through arc magmatism in the Nilgiri Block, southern India
No full textAbstract not availableVinod O. Samuel, M. Santosh, Shuwen Liu, Wei Wang, K. Sajee
Systems librarianship preparedness: A comparative analysis of skills needed and taught
No full textFor their own personal use, users may read, download, print, search, or link to the full text. Manuscripts published in Journal of Education for Library and Information Science are copyrighted to Association for Library and Information Science Education. Requests for permission to reproduce this article should be made to the University of Toronto Press using the Permission Request Form: https://www.utpjournals.press/about/permissions or by email: [email protected] systems and digital services are in rapid development and of increasing importance to meeting the needs of users, and systems librarianship is at the forefront of this development, with ever-changing expectations of expertise and areas of responsibility. The aim of this study was to determine how well library and information science (LIS) programs prepare graduate students for careers in systems librarianship. This study focused on systems librarian positions in academic libraries in the United States. Thirty systems librarian position descriptions were retrieved over a 40-month period from virtual job boards and email lists. The author performed a keyword analysis of terms from these position descriptions and compared them to keywords in course catalogs from 20 prominent, accredited LIS programs. These terms were categorized and assessed to determine the degree of similarity between the position descriptions and LIS course offerings and identify areas of potential development in LIS schools. In the majority of categories (27 out of 35), LIS schools clearly met or exceeded the coverage level found in position descriptions, but in the eight remaining cases, the LIS schools overall failed to demonstrate coverage of the topics in their course catalogs. LIS educators are encouraged to build these topics into their curricular offerings to better prepare systems librarians and any technologically savvy librarians for their professional careers
Poética da penúria: a ator beckettiano
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão, Programa de Pós-Graduação em Literatura, Florianópolis, 2013.O objeto deste estudo é refletir sobre os principais dispositivos da poética beckettiana, os testemunhos de atores históricos que trabalharam sob a direção de Samuel Beckett para propor alguns caminhos de composição de um ator particular, que, com experiências de uma preparação dramatúrgica, condensaria um corpo em penúria. Para isso, investigamos algumas das características da obra beckettiana como a influência minimalista sobre suas peças tardias, a musicalidade que permeia o seu texto teatral e a imobilidade imposta à suas personagens. Mergulhamos no íntimo dessas personagens, com a finalidade de, através do levantamento dos principais traços absorvidos pelo ator beckettiano, estabelecer relações com o ator pós-dramático. A fim de confrontar as referências estudadas, propusemo-nos a encenar o espetáculo Inomináveis # coletivo Beckett, uma reunião das peças Play, Not I, Rough for theatre I e Footfalls. Consideramos e aferimos nossas hipóteses através de depoimentos cedidos pelos atores envolvidos em nossa encenação This work aims to study the most important tools of Samuel Beckett#s art, the testimony of historical actors who worked under his direction to propose possible ways of formation a particular actor that would condensate a body in a state of penury using experiences from dramaturgical preparation. We observed some characteristics of Beckett#s work as an influence of the Minimalism in his last plays, the musicality in his theatrical texts and the immobility of his characters. We studied the characters in depth to clear relations with the post-dramatic actors by mean of recognizing the most important features of actors involved with Samuel Beckett. In order to confront our references, we put forward a staging: Inomináveis # coletivo Beckett, a sequence of Play, Not I, Rough for theatre I and Footfalls. We investigated and assessed our hypotheses using testimonies of the actors involved in our staging
Detection of secondary predation by PCR analyses of the gut contents of invertebrate generalist predators
No full textPredation by generalist predators is difficult to study in the field because of the complex effects of positive and negative interactions within and between predator species and guilds. Predation can be monitored by molecular means, through identification of prey DNA within predators. However, polymerase chain reaction (PCR) amplification of prey DNA from predators cannot discriminate between primary and secondary predation (hyperpredation), in which one predator feeds on another that has recently eaten the target prey. Here we quantify, for the first time, the potential error caused by detection of prey DNA following secondary predation, using an aphid–spider–carabid model. First, the aphid Sitobion avenae was fed to the spider Tenuiphantes tenuis and the carabid Pterostichus melanarius, and the postconsumption detection periods, for prey DNA within predators, were calculated. Aphids were then fed to spiders and the spiders to carabids. Aphid DNA was detected in the predators using primers that amplified 245- and 110-bp fragments of the mitochondrial cytochrome oxidase I gene. Fragment size and predator sex had no significant effect on detection periods. Secondary predation could be detected for up to 8 h, when carabids fed on spiders immediately after the latter had consumed aphids. Beetles tested positive up to 4 h after eating spiders that had digested their aphid prey for 4 h. Clearly, the extreme sensitivity of PCR makes detection of secondary predation more likely, and the only reliable answer in future may be to use PCR to identify, in parallel, instances of intraguild predation
Meric et al. 2015 GBE: 83 novel Staphylococcus epidermidis genome assemblies
No full textZIP archive containing contigs for 83 whole genome sequences of S. epidermidis. Metadata is attached to the Dryad submission. Contact: Prof Samuel Sheppard [email protected]
Gene loss and lineage specific restriction-modification systems associated with niche differentiation in the Campylobacter jejuni Sequence Type 403 clonal complex
No full textCampylobacter jejuni is a highly diverse species of bacteria commonly associated with infectious intestinal disease of humans and zoonotic carriage in poultry, cattle, pigs, and other animals. The species contains a large number of distinct clonal complexes that vary from host generalist lineages commonly found in poultry, livestock, and human disease cases to host-adapted specialized lineages primarily associated with livestock or poultry. Here, we present novel data on the ST403 clonal complex of C. jejuni, a lineage that has not been reported in avian hosts. Our data show that the lineage exhibits a distinctive pattern of intralineage recombination that is accompanied by the presence of lineage-specific restriction-modification systems. Furthermore, we show that the ST403 complex has undergone gene decay at a number of loci. Our data provide a putative link between the lack of association with avian hosts of C. jejuni ST403 and both gene gain and gene loss through nonsense mutations in coding sequences of genes, resulting in pseudogene formation
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