992 resultados para McEwen, Donald


Relevância:

10.00% 10.00%

Publicador:

Resumo:

We describe associations between death from invasive pneumococcal disease (IPD) and particular serogroups and sequence types (STs) determined by multilocus sequence typing (MLST) using data from Scotland. All IPD episodes where blood or cerebrospinal fluid (CSF) culture isolates were referred to the Scottish Haemophilus, Legionella, Meningococcal and Pneumococcal Reference Laboratory (SHLMPRL) from January 1992 to February 2007 were matched to death certification records by the General Register Office for Scotland. This represented 5959 patients. The median number of IPD cases in Scotland each year was 292. Deaths, from any cause, within 30 days of pneumococcal culture from blood or CSF were considered to have IPD as a contributing factor. Eight hundred and thirty-three patients died within 30 days of culture of Streptococcus pneumoniae from blood or CSF [13.95 %; 95 % confidence interval (13.10, 14.80)]. The highest death rates were in patients over the age of 75. Serotyping data exist for all years but MLST data were only available from 2001 onward. The risk ratio of dying from infection due to particular serogroups or STs compared to dying from IPD due to all other serogroups or STs was calculated. Fisher’s exact test with Bonferroni adjustment for multiple testing was used. Age adjustment was accomplished using the Cochran–Mantel–Haenszel test and 95 % confidence intervals were reported. Serogroups 3, 11 and 16 have increased probability of causing fatal IPD in Scotland while serogroup 1 IPD has a reduced probability of causing death. None of the 20 most common STs were significantly associated with death within 30 days of pneumococcal culture, after age adjustment. We conclude that there is a stronger association between a fatal outcome and pneumococcal capsular serogroup than there is between a fatal outcome and ST.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Salicylic acid is a crucial plant hormone involved defence responses against biotrophic pathogens. This thesis aimed to induce a defence response against the soil-borne biotroph, Plasmodiophora brassicae, by application of salicylic acid. Using broccoli and Arabidopsis thaliana pathway mutants I have shown that salicylic acid is essential in this interaction.

Relevância:

10.00% 10.00%

Publicador:

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pigeon milk is fed to young pigeons by both their parents. This thesis described the genetic basis of pigeon milk production in the crop and also its effect on young chickens. This revealed that pigeon milk has functional similarities to mammalian milk, and bioactives with future potential in poultry production were identified.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The resurrection grass Sporobolus stapfianus Gandoger can rapidly recover from extended periods of time in the desiccated state (water potential equilibrated to 2% relative humidity) (Gaff and Ellis, Bothalia 11:305–308 1974; Gaff and Loveys, Transactions of the Malaysian Society of Plant Physiology 3:286–287 1993). Physiological studies have been conducted in S. stapfianus to investigate the responses utilised by these desiccation-tolerant plants to cope with severe water-deficit. In a number of instances, more recent gene expression analyses in S. stapfianus have shed light on the molecular and cellular mechanisms mediating these responses. S. stapfianus is a versatile research tool for investigating desiccation-tolerance in vegetative grass tissue, with several useful characteristics for differentiating desiccation-tolerance adaptive genes from the many dehydration-responsive genes present in plants. A number of genes orthologous to those isolated from dehydrating S. stapfianus have been successfully used to enhance drought and salt tolerance in model plants as well as important crop species. In addition to the ability to desiccate and rehydrate successfully, the survival of resurrection plants in regions experiencing short sporadic rainfall events may depend substantially on the ability to tightly down-regulate cell division and cell wall loosening activities with decreasing water availability and then grow rapidly after rainfall while water is plentiful. Hence, an analysis of gene transcripts present in the desiccated tissue of resurrection plants may reveal important growth-related genes. Recent findings support the proposition that, as well as being a versatile model for devising strategies for protecting plants from water-loss, resurrection plants may be a very useful tool for pinpointing genes to target for enhancing growth rate and biomass production.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Isolation of gene transcripts from desiccated leaf tissues of the resurrection grass, Sporobolus stapfianus, resulted in the identification of a gene, SDG8i, encoding a Group 1 glycosyltransferase (UGT). Here, we examine the effects of introducing this gene, under control of the CaMV35S promoter, into the model plant Arabidopsis thaliana. Results show that Arabidopsis plants constitutively over-expressing SDG8i exhibit enhanced growth, reduced senescence, cold tolerance and a substantial improvement in protoplasmic drought tolerance. We hypothesise that expression of SDG8i in Arabidopsis negatively affects the bioactivity of metabolite/s that mediate/s environmentally-induced repression of cell division and expansion, both during normal development and in response to stress. The phenotype of transgenic plants over-expressing SDG8i suggests modulation in activities of both growth- and stress-related hormones. Plants overexpressing the UGT show evidence of elevated auxin levels, with the enzyme acting downstream of ABA to reduce drought-induced senescence. Analysis of the in vitro activity of the UGT recombinant protein product demonstrates that SDG8i can glycosylate the synthetic strigolactone analogue GR24, evoking a link with strigolactone-related processes in vivo. The large improvements observed in survival of transgenic Arabidopsis plants under cold-, salt- and drought-stress, as well as the substantial increases in growth rate and seed yield under non-stress conditions, indicates that overexpression of SDG8i in crop plants may provide a novel means of increasing plant productivity.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Sporobolus stapfianus Gandoger, one of ~40 known ‘anabiotic’grass species (i.e. ‘able to regain vital activity from a state of latent life’), is the most versatile tool for research into desiccation tolerance in vegetative grass tissue. Current knowledge on this species is presented, including the features that suit it for investigations into the plant’s ability to survive dehydration of its leaf protoplasm. The main contributors to desiccation tolerance in S. stapfianus leaves appear to be: accumulation during dehydration of protectants of membranes and proteins; mechanisms limiting oxidative damage; a retention of protein synthetic activity in late stages of drying that is linked with changes in gene expression and in the proteomic array; and an ability to retain net synthesis of ATP during drying. S. stapfianus exemplifies an advanced stage of an evolutionary trend in desiccation tolerant plants towards increased importance of the dehydration phase (for induction of tolerance, for synthesis of protectants and for proteomic changes).

Relevância:

10.00% 10.00%

Publicador:

Resumo:

On July 26–29, 2010 the 13th International Myopia Conference was held in Tübingen, Germany and included 17 separate symposia, each with 3–5 presentations. Here, in a single paper, the chairs of those Symposia describe the scientific advances noted at the conference and include the full abstracts of the individual myopia papers presented in each symposium along with the authors and their institutions. The 17 Symposia covered 7 topics: Why Study the Mechanisms of Myopia?; Novel Approaches to Risk Factors; Signaling Eye Growth- How Could Basic Biology Be Translated into Clinical Insights?; Where Are Genetic and Proteomic Approaches Leading?; How Does Visual Function Contribute to and Interact with Ametropia?; Does Eye Shape Matter?; Why Ametropia at All?

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Low glomerular (nephron) endowment has been associated with an increased risk of cardiovascular and renal disease in adulthood. Nephron endowment in humans is determined by 36 wk of gestation, while in rats and mice nephrogenesis ends several days after birth. Specific genes and environmental perturbations have been shown to regulate nephron endowment. Until now, design-based method for estimating nephron number in developing kidneys was unavailable. This was due in part to the difficulty associated with unambiguously identifying developing glomeruli in histological sections. Here, we describe a method that uses lectin histochemistry to identify developing glomeruli and the physical disector/fractionator principle to provide unbiased estimates of total glomerular number (Nglom). We have characterized Nglom throughout development in kidneys from 76 rats and model this development with a 5-parameter logistic equation to predict Nglom from embryonic day 17.25 to adulthood (r2 = 0.98). This approach represents the first design-based method with which to estimate Nglom in the developing kidney.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This paper summarizes the views, obtained via a survey instrument created by the authors and reported in studies by Stout and Wygal, of 22 accounting educator teaching exemplars from Australia. Each of these individuals has been cited for teaching excellence through receipt of one or more formal teaching awards. The paper responds to calls in Australia for increased attention to the dimensions of teaching effectiveness and to initiatives in the United States calling for a broader sharing of information among members of the academy regarding the characteristics of teaching effectiveness. Little direct evidence from the field of accounting education is available to date regarding such characteristics or antecedents of teaching effectiveness in the student learning environment. Our research therefore extends in a fundamental way the work of Stice and Stocks and Stout and Wygal. Specifically, perceptions from a sample of award-winning non-US faculties regarding the ‘drivers of teaching effectiveness’ in accounting education are recorded and analyzed. In decreasing order of perceived importance, drivers of teaching effectiveness are: having a student focus; commitment to teaching (as a profession); high levels of preparation/organization; the ability to link subject matter to the practice environment; and, instructor skills and attributes. This paper adds to our understanding of the drivers of teaching effectiveness and begins the process of creating a worldwide knowledge base in accounting education. The paper should be of interest to accounting faculty members interested in improving their teaching effectiveness and/or mentoring junior faculty members.