238 resultados para Guests


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(L-R: Mr. and Mrs. Jim Brown (actor), Mr. and Mrs. Bob Harmon (professional tennis player), Tom Harmon, Elyse Harmon, Kris Harmon, Mrs. William Powell ( wife of actor William Powell), Phillip Reed (actor), Dorothy Ford (actress)

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BACKGROUND: More than 80 % of all terrestrial plant species establish an arbuscular mycorrhiza (AM) symbiosis with Glomeromycota fungi. This plant-microbe interaction primarily improves phosphate uptake, but also supports nitrogen, mineral, and water aquisition. During the pre-contact stage, the AM symbiosis is controled by an exchange of diffusible factors from either partner. Amongst others, fungal signals were identified as a mix of sulfated and non-sulfated lipochitooligosaccharides (LCOs), being structurally related to rhizobial nodulation (Nod)-factor LCOs that in legumes induce the formation of nitrogen-fixing root nodules. LCO signals are transduced via a common symbiotic signaling pathway (CSSP) that activates a group of GRAS transcription factors (TFs). Using complex gene expression fingerprints as molecular phenotypes, this study primarily intended to shed light on the importance of the GRAS TFs NSP1 and RAM1 for LCO-activated gene expression during pre-symbiotic signaling. RESULTS: We investigated the genome-wide transcriptional responses in 5 days old primary roots of the Medicago truncatula wild type and four symbiotic mutants to a 6 h challenge with LCO signals supplied at 10(-7/-8) M. We were able to show that during the pre-symbiotic stage, sulfated Myc-, non-sulfated Myc-, and Nod-LCO-activated gene expression almost exclusively depends on the LysM receptor kinase NFP and is largely controled by the CSSP, although responses independent of this pathway exist. Our results show that downstream of the CSSP, gene expression activation by Myc-LCOs supplied at 10(-7/-8) M strictly required both the GRAS transcription factors RAM1 and NSP1, whereas those genes either co- or specifically activated by Nod-LCOs displayed a preferential NSP1-dependency. RAM1, a central regulator of root colonization by AM fungi, controled genes activated by non-sulfated Myc-LCOs during the pre-symbiotic stage that are also up-regulated in areas with early physical contact, e.g. hyphopodia and infecting hyphae; linking responses to externally applied LCOs with early root colonization. CONCLUSIONS: Since both RAM1 and NSP1 were essential for the pre-symbiotic transcriptional reprogramming by Myc-LCOs, we propose that downstream of the CSSP, these GRAS transcription factors act synergistically in the transduction of those diffusible signals that pre-announce the presence of symbiotic fungi.

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Selectivity is demonstrated in a supramolecular host:guest system using a receptor with a non-linear binding site. For the "open" receptor 1 strong binding for both flexible and rigid guests was observed. Receptor 2, with a "blocked" binding site, also bound flexible guests effectively but its affinity for rigid guests was 50 fold lower.

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Technology-based self-service (TBSS) enables consumers to complete services themselves using a technological interface. As evaluations of consumer satisfaction and commitment have typically focused on interpersonal interactions, the effect of TBSS on these is under researched . This paper explores the impact of TBSS on consumer satisfaction and on a multidimensional measure of consumer commitment.Data are collected from 241 hotel guests. The results suggest personal-service is more important for satisfaction and commitment. This has implications for marketing as the benefits of adopting TBSS are not clear. Multi-dimensional commitment provides some interesting findings and suggests the need for further research into TBSS and commitment.