49 research outputs found
Anti-citrullinated protein antibodies and high levels of rheumatoid factor are associated with systemic bone loss in patients with early untreated rheumatoid arthritis
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Food for pollinators: quantifying the nectar and pollen resources of urban flower meadows
Planted meadows are increasingly used to improve the biodiversity and aesthetic amenity value of urban areas. Although many ‘pollinator-friendly’ seed mixes are available, the floral resources these provide to flower-visiting insects, and how these change through time, are largely unknown. Such data are necessary to compare the resources provided by alternative meadow seed mixes to each other and to other flowering habitats. We used quantitative surveys of over 2 million flowers to estimate the nectar and pollen resources offered by two exemplar commercial seed mixes (one annual, one perennial) and associated weeds grown as 300m2 meadows across four UK cities, sampled at six time points between May and September 2013. Nectar sugar and pollen rewards per flower varied widely across 65 species surveyed, with native British weed species (including dandelion, Taraxacum agg.) contributing the top five nectar producers and two of the top ten pollen producers. Seed mix species yielding the highest rewards per flower included Leontodon hispidus, Centaurea cyanus and C. nigra for nectar, and Papaver rhoeas, Eschscholzia californica and Malva moschata for pollen. Perennial meadows produced up to 20x more nectar and up to 6x more pollen than annual meadows, which in turn produced far more than amenity grassland controls. Perennial meadows produced resources earlier in the year than annual meadows, but both seed mixes delivered very low resource levels early in the year and these were provided almost entirely by native weeds. Pollen volume per flower is well predicted statistically by floral morphology, and nectar sugar mass and pollen volume per unit area are correlated with flower counts, raising the possibility that resource levels can be estimated for species or habitats where they cannot be measured directly. Our approach does not incorporate resource quality information (for example, pollen protein or essential amino acid content), but can easily do so when suitable data exist. Our approach should inform the design of new seed mixes to ensure continuity in floral resource availability throughout the year, and to identify suitable species to fill resource gaps in established mixes
Are changes in bone mineral density different between groups of early rheumatoid arthritis patients treated according to a tight control strategy with or without prednisone if osteoporosis prophylaxis is applied?
C-Terminal Juxtamembrane Region Of Full-Length M2 Protein Forms A Membrane Surface Associated Amphipathic Helix
The influenza A M2 protein is a 97-residue integral membrane protein involved in viral budding and proton conductance. Although crystal and NMR structures exist of truncated constructs of the protein, there is disagreement between models and only limited structural data are available for the full-length protein. Here, the structure of the C-terminal juxtamembrane region (sites 50–60) is investigated in the full-length M2 protein using site-directed spin-labeling electron paramagnetic resonance (EPR) spectroscopy in lipid bilayers. Sites 50–60 were chosen for study because this region has been shown to be critical to the role the M2 protein plays in viral budding. Continuous wave EPR spectra and power saturation data in the presence of paramagnetic membrane soluble oxygen are consistent with a membrane surface associated amphipathic helix. Comparison between data from the C-terminal juxtamembrane region in full-length M2 protein with data from a truncated M2 construct demonstrates that the line shapes and oxygen accessibilities are remarkably similar between the full-length and truncated form of the protein