EFFECTS OF UTILIZING CROP RESIDUES IN WINTER FEEDING SYSTEMS ON BEEF COW PERFORMANCE, REPRODUCTIVE EFFICIENCY AND ECONOMICS

Over 2 years (Year 1, 2009-2010; Year 2, 2010-2011), two separate experiments were conducted to evaluate the effects of winter feeding system (n=3) on beef cow performance, reproductive performance, economics and forage degradability. The three systems (treatments) were grazing pea crop residue (PEA) cv. ‘Performance 40-10’ (Year 1, TDN = 50.2%, CP = 7.3%; Year 2, TDN = 56.9%, CP = 8.9%) in field paddocks, grazing oat crop residue (OAT) cv. ‘Baler’ (Year 1, TDN = 59.1%, CP = 2.9%; Year 2, TDN = 66.9%, CP = 5.3%) in field paddocks, and feeding mixed grass-legume hay in drylot pens (DL) (Year 1, TDN = 61.4%; CP = 8.8%; Year 2, TDN = 52.3%, CP = 12.3%). In the first experiment, 90 dry, pregnant Black Angus cows (Year 1, 629 kg ± 74 kg; Year 2, 665 ± 69 kg) stratified by body weight (BW) and days pregnant were randomly allocated to 1 of the 3 systems. Cows were allocated feed in the field or pen on a 3 d basis and supplemented oat grain daily at 0.4-0.6% BW depending on environmental conditions. Dry matter intake (DMI) was estimated for each system using the herbage weight disappearance method. Cow BW, body condition score (BCS), and rib and rump fat were measured at start and end of trial and cow BW was corrected for conceptus gain based on calving data. When data from the first 20 d were pooled over 2 years, initial cow BW was greater (P < 0.01) for the DL and OAT cows compared to the PEA cows and final cow BW was different (P < 0.01) between all 3 winter feeding systems. The change in BW was also greater (P < 0.01) for DL cows compared to cows on the OAT and PEA treatments. Analysis of the first 20 d of Year 1 study period and the total Year 2 study period, showed a significant (P < 0.01) year by treatment interaction for final BW and BW change. The differences (P < 0.01) in initial BW, final BW and BW change between the first 20 d of Year 1 study period and the total Year 2 study period (20 d) suggest feed quality, animal preference and weather conditions may cause difficulties when grazing residues in winter grazing systems. Analysis of the entire trial period in Year 1 (62 d) indicates differences (P 0.05) was found for cow rib and rump fat in Year 2 and no difference (P > 0.05) was found for BCS in either Year 1 or Year 2 for cows managed in all 3 systems. Differences (P 0.05) cows managed in the DL and PEA or OAT and PEA systems. Costs per cow per day were $1.22,$1.01 and $2.77 for PEA, OAT and DL systems in Year 1, respectively. In Year 2, cow costs per day were$1.59, $1.44 and$1.84 for PEA, OAT and DL systems, respectively. In experiment 2, three ruminally cannulated, dry Holstein cows were fed a silage based total mixed ration (TMR) of 22 kg barley silage, 7 kg chopped alfalfa hay and 1 kg energy supplement (DAC-485). In-situ degradability was studied to determine the extent of degradation of pea, oat and grass-legume hay collected at start (SOT) and end of test (EOT) in experiment one. Rate of degradation (Kd) of DM was greater (P 0.05) were observed between either OAT SOT and OAT EOT or PEA SOT and PEA EOT for S, D, U, ED or RU suggesting that weathering did not have an effect on the degradability of the forages. The results of these experiments show that it is possible to maintain cow BW through the winter months in Western Canada by grazing oat crop residues, which have the potential to reduce winter feeding costs

Auger Electron Cascades in Water and Ice

Secondary electron cascades can induce significant ionisation in condensed matter due to electron-atom collisions. This is of interest in the context of diffraction and imaging using X-rays, where radiation damage is the main limiting factor for achieving high resolution data. Here we present new results on electron-induced damage on liquid water and ice, from the simulation of Auger electron cascades. We have compared our theoretical estimations to the available experimental data on elastic and inelastic electron-molecule interactions for water and found the theoretical results for elastic cross sections to be in very good agreement with experiment. As a result of the cascade we find that the average number of secondary electrons after 100 fs in ice is about 25, slightly higher than in water, where it is about 20. The difference in damage between ice and water is discussed in the context of sample handling for biomolecular systems.Comment: 19 pages, 8 figures. Includes slight corrections to the version submitted for publicatio

Recovering from COVID-19 Building Closures: Guidance Document

While the country comes to terms with the inevitable impact that SARS-CoV-2, the virus that causes COVID-19, will have on our lives and communities, public health authorities remain focused on breaking the chain of transmission. Managing the risk has resulted in widespread closures of businesses, schools, universities, resorts, and other facilities deemed “non-essential.” Practically speaking, this means closing buildings and ceasing operations. For building owners and operators, this poses a significant challenge to protect their assets and to ensure they are ready to reoccupy once the pandemic subsides

How Changes in Extracellular Matrix Mechanics and Gene Expression Variability Might Combine to Drive Cancer Progression

Changes in extracellular matrix (ECM) structure or mechanics can actively drive cancer progression; however, the underlying mechanism remains unknown. Here we explore whether this process could be mediated by changes in cell shape that lead to increases in genetic noise, given that both factors have been independently shown to alter gene expression and induce cell fate switching. We do this using a computer simulation model that explores the impact of physical changes in the tissue microenvironment under conditions in which physical deformation of cells increases gene expression variability among genetically identical cells. The model reveals that cancerous tissue growth can be driven by physical changes in the microenvironment: when increases in cell shape variability due to growth-dependent increases in cell packing density enhance gene expression variation, heterogeneous autonomous growth and further structural disorganization can result, thereby driving cancer progression via positive feedback. The model parameters that led to this prediction are consistent with experimental measurements of mammary tissues that spontaneously undergo cancer progression in transgenic C3(1)-SV40Tag female mice, which exhibit enhanced stiffness of mammary ducts, as well as progressive increases in variability of cell-cell relations and associated cell shape changes. These results demonstrate the potential for physical changes in the tissue microenvironment (e.g., altered ECM mechanics) to induce a cancerous phenotype or accelerate cancer progression in a clonal population through local changes in cell geometry and increased phenotypic variability, even in the absence of gene mutation

Resolving the cofactor-binding site in the proline biosynthetic enzyme human pyrroline-5-carboxylate reductase 1

Pyrroline-5-carboxylate reductase (PYCR) is the final enzyme in proline biosynthesis, catalyzing the NAD(P)H-dependent reduction of [?]1-pyrroline-5-carboxylate (P5C) to proline. Mutations in the PYCR1 gene alter mitochondrial function and cause the connective tissue disorder cutis laxa. Furthermore, PYCR1 is overexpressed in multiple cancers, and the PYCR1 knock-out suppresses tumorigenic growth, suggesting that PYCR1 is a potential cancer target. However, inhibitor development has been stymied by limited mechanistic details for the enzyme, particularly in light of a previous crystallographic study that placed the cofactor-binding site in the C-terminal domain rather than the anticipated Rossmann fold of the N-terminal domain. To fill this gap, we report crystallographic, sedimentation- velocity, and kinetics data for human PYCR1. Structures of binary complexes of PYCR1 with NADPH or proline determined at 1.9 Å resolution provide insight into cofactor and substrate recognition.WeseeNADPHbound to the Rossmann fold, over 25 Å from the previously proposed site. The 1.85 Å resolution structure of a ternary complex containing NADPH and a P5C/proline analog provides a model of the Michaelis complex formed during hydride transfer. Sedimentation velocity shows that PYCR1 forms a concentration-dependent decamer in solution, consistent with the pentamer-of-dimers assembly seen crystallographically. Kinetic and mutational analysis confirmed several features seen in the crystal structure, including the importance of a hydrogen bond between Thr-238 and the substrate as well as limited cofactor discrimination

Dynamic palmitoylation events following T-cell receptor signaling

Palmitoylation is the reversible addition of palmitate to cysteine via a thioester linkage. The reversible nature of this modification makes it a prime candidate as a mechanism for regulating signal transduction in T-cell receptor signaling. Following stimulation of the T-cell receptor we find a number of proteins are newly palmitoylated, including those involved in vesicle-mediated transport and Ras signal transduction. Among these stimulation-dependent palmitoylation targets are the v-SNARE VAMP7, important for docking of vesicular LAT during TCR signaling, and the largely undescribed palmitoyl acyltransferase DHHC18 that is expressed in two isoforms in T cells. Using our newly developed On-Plate Palmitoylation Assay (OPPA), we show DHHC18 is capable of palmitoylating VAMP7 at Cys183. Cellular imaging shows that the palmitoylation-deficient protein fails to be retained at the Golgi and to localize to the immune synapse upon T cell activation

Lamellipodin tunes cell migration by stabilizing protrusions and promoting adhesion formation

Efficient migration on adhesive surfaces involves the protrusion of lamellipodial actin networks and their subsequent stabilization by nascent adhesions. The actin-binding protein lamellipodin (Lpd) is thought to play a critical role in lamellipodium protrusion, by delivering Ena/VASP proteins onto the growing plus ends of actin filaments and by interacting with the WAVE regulatory complex, an activator of the Arp2/3 complex, at the leading edge. Using B16-F1 melanoma cell lines, we demonstrate that genetic ablation of Lpd compromises protrusion efficiency and coincident cell migration without altering essential parameters of lamellipodia, including their maximal rate of forward advancement and actin polymerization. We also confirmed lamellipodia and migration phenotypes with CRISPR/Cas9-mediated Lpd knockout Rat2 fibroblasts, excluding cell type-specific effects. Moreover, computer-aided analysis of cell-edge morphodynamics on B16-F1 cell lamellipodia revealed that loss of Lpd correlates with reduced temporal protrusion maintenance as a prerequisite of nascent adhesion formation. We conclude that Lpd optimizes protrusion and nascent adhesion formation by counteracting frequent, chaotic retraction and membrane ruffling.This article has an associated First Person interview with the first author of the paper

Non-local effects in the mean-field disc dynamo. II. Numerical and asymptotic solutions

The thin-disc global asymptotics are discussed for axisymmetric mean-field dynamos with vacuum boundary conditions allowing for non-local terms arising from a finite radial component of the mean magnetic field at the disc surface. This leads to an integro-differential operator in the equation for the radial distribution of the mean magnetic field strength, $Q(r)$ in the disc plane at a distance $r$ from its centre; an asymptotic form of its solution at large distances from the dynamo active region is obtained. Numerical solutions of the integro-differential equation confirm that the non-local effects act similarly to an enhanced magnetic diffusion. This leads to a wider radial distribution of the eigensolution and faster propagation of magnetic fronts, compared to solutions with the radial surface field neglected. Another result of non-local effects is a slowly decaying algebraic tail of the eigenfunctions outside the dynamo active region, $Q(r)\sim r^{-4}$, which is shown to persist in nonlinear solutions where $\alpha$-quenching is included. The non-local nature of the solutions can affect the radial profile of the regular magnetic field in spiral galaxies and accretion discs at large distances from the centre.Comment: Revised version, as accepted; Geophys. Astrophys. Fluid Dyna