An investigation into the role of place attachment within extreme sport tourism

Extreme sport participation is a growing phenomenon, both in terms of active and passive consumption. Nevertheless this growth is not mirrored in the academic literature where a clear dearth in research into extreme sport tourism consumption is evident. The conceptualisation of sport tourism is of a unique interaction of three components, namely: activity, people and place, although some argue that the role of place is unclear. Place, within a tourism context, is concerned with the destination within which the tourist activity takes place and is linked to attachment and destination loyalty. As the role of place within sport tourism is ambiguous, it is similarly unclear as to what constitutes attachment within sport tourism consumption. This study in responding to calls for research within the context of extreme sports seeks to identify the factors which influence attachment within an extreme sport tourism context. The study is based on the 2014 Isle of Man TT motorcycle race and contributes to the wider understanding of the components of attachment. From this study we propose the development of a theoretical model for researchers who wish to better understand the role of place within an extreme sport tourism context

Effect of environmental stress factors on the uptake and survival of Campylobacter jejuni in Acanthamoeba castellanii

<p>Abstract</p> <p>Background</p> <p><it>Campylobacter jejuni</it> is a major cause of bacterial food-borne illness in Europe and North America. The mechanisms allowing survival in the environment and transmission to new hosts are not well understood. Environmental free-living protozoa may facilitate both processes. Pre-exposure to heat, starvation, oxidative or osmotic stresses encountered in the environment may affect the subsequent interaction of <it>C. jejuni</it> with free-living protozoa. To test this hypothesis, we examined the impact of environmental stress on expression of virulence-associated genes (<it>ciaB, dnaJ,</it> and <it>htrA</it>) of <it>C. jejuni</it> and on its uptake by and intracellular survival within <it>Acanthamoeba castellanii</it>.</p> <p>Results</p> <p>Heat, starvation and osmotic stress reduced the survival of <it>C. jejuni</it> significantly, whereas oxidative stress had no effect. Quantitative RT-PCR experiments showed that the transcription of virulence genes was slightly up-regulated under heat and oxidative stresses but down-regulated under starvation and osmotic stresses, the <it>htrA</it> gene showing the largest down-regulation in response to osmotic stress. Pre-exposure of bacteria to low nutrient or osmotic stress reduced bacterial uptake by amoeba, but no effect of heat or oxidative stress was observed. Finally, <it>C. jejuni</it> rapidly lost viability within amoeba cells and pre-exposure to oxidative stress had no significant effect on intracellular survival. However, the numbers of intracellular bacteria recovered 5 h post-gentamicin treatment were lower with starved, heat treated or osmotically stressed bacteria than with control bacteria. Also, while ~1.5 × 10³ colony forming unit/ml internalized bacteria could typically be recovered 24 h post-gentamicin treatment with control bacteria, no starved, heat treated or osmotically stressed bacteria could be recovered at this time point. Overall, pre-exposure of <it>C. jejuni</it> to environmental stresses did not promote intracellular survival in <it>A. castellanii</it>.</p> <p>Conclusions</p> <p>Together, these findings suggest that the stress response in <it>C. jejuni</it> and its interaction with <it>A. castellanii</it> are complex and multifactorial, but that pre-exposure to various stresses does not prime <it>C. jejuni</it> for survival within <it>A. castellanii</it>.</p

Solvent-Controlled Chemoselectivity in the Photolytic Release of Hydroxamic Acids and Carboxamides from Solid Support

The synthetic utility and theoretical basis of a photolabile hydroxylamine-linker are presented. The developed protocols enable the efficient synthesis and chemoselective photolytic release of either hydroxamates or carboxamides from solid support. The bidetachable mode of the linker unit is uniquely dependent on the solvent. Hydroxamic acids are obtained by performing photolysis in protic solvents, whereas photolysis in aprotic solvents enables the selective release of carboxamides

A Mutational Analysis of the Endophilin-A N-BAR Domain Performed in Living Flies

BACKGROUND: Endophilin is a cytoplasmic protein with an important function in clathrin-dependent endocytosis at synapses and elsewhere. Endophilin has a BAR (Bin/Amphiphysin/Rvs-homology) domain, which is implicated in the sensing and induction of membrane curvature. Previous structure-function studies of the endophilin-A BAR domain have almost exclusively been made in reduced systems, either in vitro or ex vivo in cultured cells. To extend and complement this work, we have analyzed the role played by the structural features of the endophilin-A BAR domain in Drosophila in vivo. METHODOLOGY/PRINCIPAL FINDINGS: The study is based on genetic rescue of endophilin-A (endoA) null mutants with wild type or mutated endoA transgenes. We evaluated the viability of the rescuants, the locomotor behavior in adult flies and the neurotransmission at the larval neuromuscular junction. Whereas mutating the endophilin BAR domain clearly affected adult flies, larval endophilin function was surprisingly resistant to mutagenesis. Previous reports have stressed the importance of a central appendage on the convex BAR surface, which forms a hydrophobic ridge able to directly insert into the lipid bilayer. We found that the charge-negative substitution A66D, which targets the hydrophobic ridge and was reported to completely disrupt the ability of endophilin-BAR to tubulate liposomes in vitro, rescued viability and neurotransmission with the same efficiency as wild type endoA transgenes, even in adults. A similar discrepancy was found for the hydrophilic substitutions A63S/A66S and A63S/A66S/M70Q. The A66W mutation, which introduces a bulky hydrophobic side chain and induces massive vesiculation of liposomes in vitro, strongly impeded eye development, even in presence of the endogenous endoA gene. Substantial residual function was observed in larvae rescued with the EndoA(Arf) transgene, which encodes a form of endophilin-A that completely lacks the central appendage. Whereas a mutation (D151P) designed to increase the BAR curvature was functional, another mutation (P143A, DeltaLEN) designed to decrease the curvature was not. CONCLUSIONS/SIGNIFICANCE: Our results provide novel insight into the structure/function relationship of the endophilin-A BAR domain in vivo, especially with relation to synaptic function

Distribution of silver in rats following 28 days of repeated oral exposure to silver nanoparticles or silver acetate

<p>Abstract</p> <p>Background</p> <p>The study investigated the distribution of silver after 28 days repeated oral administration of silver nanoparticles (AgNPs) and silver acetate (AgAc) to rats. Oral administration is a relevant route of exposure because of the use of silver nanoparticles in products related to food and food contact materials.</p> <p>Results</p> <p>AgNPs were synthesized with a size distribution of 14 ± 4 nm in diameter (90% of the nanoparticle volume) and stabilized in aqueous suspension by the polymer polyvinylpyrrolidone (PVP). The AgNPs remained stable throughout the duration of the 28-day oral toxicity study in rats. The organ distribution pattern of silver following administration of AgNPs and AgAc was similar. However the absolute silver concentrations in tissues were lower following oral exposure to AgNPs. This was in agreement with an indication of a higher fecal excretion following administration of AgNPs. Besides the intestinal system, the largest silver concentrations were detected in the liver and kidneys. Silver was also found in the lungs and brain. Autometallographic (AMG) staining revealed a similar cellular localization of silver in ileum, liver, and kidney tissue in rats exposed to AgNPs or AgAc.</p> <p>Using transmission electron microscopy (TEM), nanosized granules were detected in the ileum of animals exposed to AgNPs or AgAc and were mainly located in the basal lamina of the ileal epithelium and in lysosomes of macrophages within the lamina propria. Using energy dispersive x-ray spectroscopy it was shown that the granules in lysosomes consisted of silver, selenium, and sulfur for both AgNP and AgAc exposed rats. The diameter of the deposited granules was in the same size range as that of the administered AgNPs. No silver granules were detected by TEM in the liver.</p> <p>Conclusions</p> <p>The results of the present study demonstrate that the organ distribution of silver was similar when AgNPs or AgAc were administered orally to rats. The presence of silver granules containing selenium and sulfur in the intestinal wall of rats exposed to either of the silver forms suggests a common mechanism of their formation. Additional studies however, are needed to gain further insight into the underlying mechanisms of the granule formation, and to clarify whether AgNPs dissolve in the gastrointestinal system and/or become absorbed and translocate as intact nanoparticles to organs and tissues.</p