FABRICATED CUT BEEF PRICES AS LEADING INDICATORS OF FED CATTLE PRICE

Temporal relationships are investigated among fabricated cut prices, carcass value, and fed cattle prices. Also, linkages between fed cattle and wholesale beef prices are examined using vector autoregressive (VAR) techniques. Results, using daily prices over the 1980-85 period, suggested that fabricated cut prices and cattle prices are related to the imputed carcass value, carcass quote, and fed cattle prices. In addition, three fabricated cuts dominate as leading indicators of fed cattle prices of most fabricated cut prices. They are strip loin and bottom and top round prices. VAR models outperform the univariate and random-walk models of forecasting ability.Demand and Price Analysis, Livestock Production/Industries,

Using selenomethionyl derivatives to assign sequence in low-resolution structures of the AP2 clathrin adaptor.

Selenomethionine incorporation is a powerful technique for assigning sequence to regions of electron density at low resolution. Genetic introduction of methionine point mutations and the subsequent preparation and crystallization of selenomethionyl derivatives permits unambiguous sequence assignment by enabling the placement of the anomalous scatterers (Se atoms) thus introduced. Here, the use of this approach in the assignment of sequence in a part of the AP2 clathrin adaptor complex that is responsible for clathrin binding is described. AP2 plays a pivotal role in clathrin-mediated endocytosis, a tightly regulated process in which cell-surface transmembrane proteins are internalized from the plasma membrane by incorporation into lipid-enclosed transport vesicles. AP2 binds cargo destined for internalization and recruits clathrin, a large trimeric protein that helps to deform the membrane to produce the transport vesicle. By selenomethionine labelling of point mutants, it was shown that the clathrin-binding site is buried within a deep cleft of the AP2 complex. A membrane-stimulated conformational change in AP2 releases the clathrin-binding site from autoinhibition, thereby linking clathrin recruitment to membrane localization.We would like to thank the I02, I03 and I04-1 beamline staff at the Diamond Light Source (mx6641) and Chris Oubridge for advice and assistance with SeMet mapping of the hinge residues. D.J.O. and B.T.K. are supported by Wellcome Trust Principal Research Fellowship (090909/Z/09/Z). S.C.G. is supported by a Sir Henry Dale Fellowship from the Wellcome Trust and the Royal Society (098406/Z/12/Z). CIMR is supported by a Wellcome Trust Strategic Award (079895).This is the final version of the article. It first appeared from the International Union of Crystallography via http://dx.doi.org/10.1107/S205979831502158

Structural studies of non-classical sialidases

Streptococcus pneumoniae is a common resident of the human nasorpharynx that can cause severe illness, including bacterial meningitis and pneumonia. Ruminococcus gnavus is a commensal resident of the human gastrointestinal tract, present in the vast majority and overrepresented in those with inflammatory bowel disease. Both bacteria exploit very different niches, however both make use of sialidases, a class of enzymes that releases terminal sialic acids from sialoglycoconjugates by hydrolysing the α-glycosidic linkage. There are three pneumococcal sialidases: SpNanA, a hydrolytic sialdiase; SpNanB, an intra-molecular trans-sialidase; and SpNanC. The primary reaction product of SpNanC is Neu5Ac2en (2-deoxy-2,3-didehydro-N-acetylneuraminic acid, also known as DANA), a potent inhibitor of hydrolytic bacterial and viral sialidases. The crystal structure of SpNanC in complex with Neu5Ac2en has been solved and a reaction mechanism for its formation proposed. R. gnavus can grow on sialylated substrates however it does not grow on sialic acid. The crystal structure of RgNanH has also been solved, confirming that it is an intra-molecular trans-sialidase, like SpNanB, that produces 2,7-anhydro-Neu5Ac, a sialic acid derivative with an intra-molecular linkage. This suggests a method of partitioning an important carbon source in a competitive environment. These works highlight the importance of thorough structural characterisation of sialidases, because although they may appear superficially very similar, they have significant diversity in their reaction mechanisms and their responses to inhibitors

Calcium-Dependent But Action Potential-Independent BCM-Like Metaplasticity in the Hippocampus

The Bienenstock, Cooper and Munro (BCM) computational model, which incorporates a metaplastic sliding threshold for LTP induction, accounts well for experience-dependent changes in synaptic plasticity in the visual cortex. BCM-like metaplasticity over a shorter timescale has also been observed in the hippocampus, thus providing a tractable experimental preparation for testing specific predictions of the model. Here, using extracellular and intracellular electrophysiological recordings from acute rat hippocampal slices, we tested the critical BCM predictions (1) that high levels of synaptic activation will induce a metaplastic state that spreads across dendritic compartments, and (2) that postsynaptic cell-firing is the critical trigger for inducing that state. In support of the first premise, high-frequency priming stimulation inhibited subsequent long-term potentiation and facilitated subsequent long-term depression at synapses quiescent during priming, including those located in a dendritic compartment different to that of the primed pathway. These effects were not dependent on changes in synaptic inhibition or NMDA/ metabotropic glutamate receptor function. However, in contrast to the BCM prediction, somatic action potentials during priming were neither necessary nor sufficient to induce the metaplasticity effect. Instead, in broad agreement with derivatives of the BCM model, calcium as released from intracellular stores and triggered byM1 muscarinic acetylcholine receptor activation was critical for altering subsequent synapticplasticity. These results indicate that synaptic plasticity in stratum radiatum of CA1 can be homeostatically regulated by the cell-wide history of synaptic activity through a calcium-dependent but action potential-independent mechanis

Who the hell was that? Stories, bodies and actions in the world

This article explores a two-way relationship between stories and the experiential actions of bodies in the world. Through an autoethnographic approach, the article presents a series of interlinked story fragments in an effort to show and evoke a feel for the ways in which stories, bodies, and actions influence and shape each other over time. It offers some reflections on the experiences the stories portray from the perspective of a social constructionist conception of narrative theory and suggest that while stories exert a powerful influence on the actions of our bodies, our bodies intrude on or ‘talk back’ to this process because bodies have an existence beyond stories

Muon-Spin Rotation Measurements of an Unusual Vortex-Glass Phase in the Layered Superconductor Bi2.15Sr1.85CaCu2O8+δ

Muon-spin rotation measurements, performed on the mixed state of the classic anisotropic superconductor Bi2.15Sr1.85CaCu2O8+δ, obtain quantities directly related to two- and three-body correlations of vortices in space. A novel phase diagram emerges from such local probe measurements of the bulk, revealing an unusual glassy state at intermediate fields which appears to freeze continuously from the equilibrium vortex liquid but differs both from the lattice and the conventional high-field vortex glass state in its structure.Publisher PDFPeer reviewe