3,048 research outputs found
A way of life: considering and curating the Sainsbury African Galleries
This statement attempts to present a critical examination of my work and achievements as a curator and artist over a period of almost thirty years from 1987, when I joined the Africa section of what was then the Ethnography Department of the British Museum (BM), to the present day. In so doing I hope to convey my evolving understanding of my role as a curator - and the theoretical contexts that underpin the choices I was faced with during this period, played out against the backdrop of the momentous socio-political events taking place in the world
BrEPS: a flexible and automatic protocol to compute enzyme-specific sequence profiles for functional annotation
<p>Abstract</p> <p>Background</p> <p>Models for the simulation of metabolic networks require the accurate prediction of enzyme function. Based on a genomic sequence, enzymatic functions of gene products are today mainly predicted by sequence database searching and operon analysis. Other methods can support these techniques: We have developed an automatic method "BrEPS" that creates highly specific sequence patterns for the functional annotation of enzymes.</p> <p>Results</p> <p>The enzymes in the UniprotKB are identified and their sequences compared against each other with BLAST. The enzymes are then clustered into a number of trees, where each tree node is associated with a set of EC-numbers. The enzyme sequences in the tree nodes are aligned with ClustalW. The conserved columns of the resulting multiple alignments are used to construct sequence patterns. In the last step, we verify the quality of the patterns by computing their specificity. Patterns with low specificity are omitted and recomputed further down in the tree. The final high-quality patterns can be used for functional annotation. We ran our protocol on a recent Swiss-Prot release and show statistics, as well as a comparison to PRIAM, a probabilistic method that is also specialized on the functional annotation of enzymes. We determine the amount of true positive annotations for five common microorganisms with data from BRENDA and AMENDA serving as standard of truth. BrEPS is almost on par with PRIAM, a fact which we discuss in the context of five manually investigated cases.</p> <p>Conclusions</p> <p>Our protocol computes highly specific sequence patterns that can be used to support the functional annotation of enzymes. The main advantages of our method are that it is automatic and unsupervised, and quite fast once the patterns are evaluated. The results show that BrEPS can be a valuable addition to the reconstruction of metabolic networks.</p
The effect of cereal type and enzyme supplementation on carcass characteristics, volatile fatty acids and intestinal microflora and boar taint in entire male pigs
A 2 × 2 factorial experiment was conducted to investigate the effects of cereal type (barley v. oat) and exogenous enzyme supplementation (with or without) on intestinal fermentation, and on indole and skatole levels in the intestinal content and the adipose tissue in finisher boars. The experimental treatments were as follows: (i) barley-based diet, (ii) barley-based diet with enzyme supplement, (iii) oat-based diet and (iv) oat-based diet with enzyme supplement. The enzyme supplement contained endo-1,3(4)-β-glucanase (EC 3.2.1.6) and endo-1,4-β-xylanase (EC 3.2.1.8). The animals were fed ad libitum for 45 days from 76.0 to 113.6 kg live weight. Feeding barley-based diets led to higher (P 0.05) between the experimental treatments. Pigs offered the barley-based diets had lower (P < 0.001) indole concentrations in the adipose tissue compared with those fed the oat-based diet. In conclusion, barley-based diets were more efficient than oat-based diets in limiting concentrations of indole in the adipose tissu
A single-cross, RNA interference-based genetic tool for examining the long-term maintenance of homeostatic plasticity
The effects of dietary mannaoligosaccharides on cecal parameters and the concentrations of enteric bacteria in the ceca of salmonella-challenged broiler chicks
The ability of different enteric pathogens and coliforms to trigger agglutination of yeast cells (Saccharomyces cerevisiae, NCYC 1026) and a yeast cell wall preparation (MOS) was examined. Five of seven strains of Escherichia coli and 7 of 10 strains of Salmonella typhimurium and Salmonella enteritidis agglutinated MOS and Sac. cerevisiae cells. Strains of Salmonella choleraesuis, Salmonella pullorum, and Campylobacter did not lead to agglutination. Two strains that agglutinated MOS (S. typhimurium 29E and Salmonella dublin) and one nonagglutinating strain (S. typhimurium 27A) were selected as challenge organisms for in vivo studies in chicks under controlled conditions. In a series of three trials in which 3-d-old chicks were orally challenged with 10(4) cfu of S. typhimurium 29E, birds receiving 4,000 ppm of dietary MOS had reduced cecal S. typhimurium 29E concentrations (5.40 vs 4.01 log cfu/ g; P < 0.05) at Day 10. In a second series of three trials with S. dublin as challenge organism, the number of birds that tested salmonella positive in the ceca at Day 10 was less when MOS was part of the diet (90 vs 56%; P < 0.05). To test the effect of MOS on concentrations of bacteria that do not express Type 1 fimbriae, a challenge trial was conducted with S. typhimurium 27A. However, strain 27A did not colonize the birds sufficiently to evaluate whether MOS affected its cecal concentration. Mannanoligosaccharide did not significantly reduce the concentrations of cecal coliforms (P < 0.10) although they were numerically lower. It had no effect on cecal concentrations of lactobacilli, enterococci, anaerobic bacteria, lactate, volatile fatty acid, or cecal p
Identification, functional characterization and developmental regulation of sesquiterpene synthases from sunflower capitate glandular trichomes
<p>Abstract</p> <p>Background</p> <p>Sesquiterpene lactones are characteristic metabolites of Asteraceae (or Compositae) which often display potent bioactivities and are sequestered in specialized organs such as laticifers, resin ducts, and trichomes. For characterization of sunflower sesquiterpene synthases we employed a simple method to isolate pure trichomes from anther appendages which facilitated the identification of these genes and investigation of their enzymatic functions and expression patterns during trichome development.</p> <p>Results</p> <p>Glandular trichomes of sunflower (<it>Helianthus annuus </it>L.) were isolated, and their RNA was extracted to investigate the initial steps of sesquiterpene lactone biosynthesis. Reverse transcription-PCR experiments led to the identification of three sesquiterpene synthases. By combination of <it>in vitro </it>and <it>in vivo </it>characterization of sesquiterpene synthase gene products in <it>Escherichia coli </it>and <it>Saccharomyces cerevisiae</it>, respectively, two enzymes were identified as germacrene A synthases, the key enzymes of sesquiterpene lactone biosynthesis. Due to the very low <it>in vitro </it>activity, the third enzyme was expressed <it>in vivo </it>in yeast as a thioredoxin-fusion protein for functional characterization. In <it>in vivo </it>assays, it was identified as a multiproduct enzyme with the volatile sesquiterpene hydrocarbon δ-cadinene as one of the two main products with α-muuorlene, β-caryophyllene, α-humulene and α-copaene as minor products. The second main compound remained unidentified. For expression studies, glandular trichomes from the anther appendages of sunflower florets were isolated in particular developmental stages from the pre- to the post-secretory phase. All three sesquiterpene synthases were solely upregulated during the biosynthetically active stages of the trichomes. Expression in different aerial plant parts coincided with occurrence and maturity of trichomes. Young roots with root hairs showed expression of the sesquiterpene synthase genes as well.</p> <p>Conclusion</p> <p>This study functionally identified sesquiterpene synthase genes predominantly expressed in sunflower trichomes. Evidence for the transcriptional regulation of sesquiterpene synthase genes in trichome cells suggest a potential use for these specialized cells for the identification of further genes involved in the biosynthesis, transport, and regulation of sesquiterpene lactones.</p
Financial Motivation Undermines Maintenance in an Intensive Diet and Activity Intervention
Financial incentives are widely used in health behavior interventions. However, self-determination theory posits that emphasizing financial incentives can have negative consequences if experienced as controlling. Feeling controlled into performing a behavior tends to reduce enjoyment and undermine maintenance after financial contingencies are removed (the undermining effect). We assessed participants' context-specific financial motivation to participate in the Make Better Choices trial—a trial testing four different strategies for improving four health risk behaviors: low fruit and vegetable intake, high saturated fat intake, low physical activity, and high sedentary screen time. The primary outcome was overall healthy lifestyle change; weight loss was a secondary outcome. Financial incentives were contingent upon meeting behavior goals for 3 weeks and became contingent upon merely providing data during the 4.5-month maintenance period. Financial motivation for participation was assessed at baseline using a 7-item scale (α = .97). Across conditions, a main effect of financial motivation predicted a steeper rate of weight regained during the maintenance period, t(165) = 2.15, P = .04. Furthermore, financial motivation and gender interacted significantly in predicting maintenance of healthy diet and activity changes, t(160) = 2.42, P = .016, such that financial motivation had a more deleterious influence among men. Implications for practice and future research on incentivized lifestyle and weight interventions are discussed
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