Water in Cavity−Ligand Recognition

We use explicit solvent molecular dynamics simulations to estimate free energy, enthalpy, and entropy changes along the cavity-ligand association coordinate for a set of seven model systems with varying physicochemical properties. Owing to the simplicity of the considered systems we can directly investigate the role of water thermodynamics in molecular recognition. A broad range of thermodynamic signatures is found in which water (rather than cavity or ligand) enthalpic or entropic contributions appear to drive cavity-ligand binding or rejection. The unprecedented, nanoscale picture of hydration thermodynamics can help the interpretation and design of protein-ligand binding experiments. Our study opens appealing perspectives to tackle the challenge of solvent entropy estimation in complex systems and for improving molecular simulation models

Bone Marrow Transplantation Results in Human Donor Blood Cells Acquiring and Displaying Mouse Recipient Class I MHC and CD45 Antigens on Their Surface

Background: Mouse models of human disease are invaluable for determining the differentiation ability and functional capacity of stem cells. The best example is bone marrow transplants for studies of hematopoietic stem cells. For organ studies, the interpretation of the data can be difficult as transdifferentiation, cell fusion or surface antigen transfer (trogocytosis) can be misinterpreted as differentiation. These events have not been investigated in hematopoietic stem cell transplant models. Methodology/Principal Findings: In this study we investigated fusion and trogocytosis involving blood cells during bone marrow transplantation using a xenograft model. We report that using a standard SCID repopulating assay almost 100 % of the human donor cells appear as hybrid blood cells containing both mouse and human surface antigens. Conclusion/Significance: Hybrid cells are not the result of cell-cell fusion events but appear to be due to efficient surface antigen transfer, a process referred to as trogocytosis. Antigen transfer appears to be non-random and includes all donor cells regardless of sub-type. We also demonstrate that irradiation preconditioning enhances the frequency of hybrid cell

Management practices for control of ragwort species

The ragwort species common or tansy ragwort (Jacobaea vulgaris, formerly Senecio jacobaea), marsh ragwort (S. aquaticus), Oxford ragwort (S. squalidus) and hoary ragwort (S. erucifolius) are native in Europe, but invaded North America, Australia and New Zealand as weeds. The abundance of ragwort species is increasing in west-and central Europe. Ragwort species contain different groups of secondary plant compounds defending them against generalist herbivores, contributing to their success as weeds. They are mainly known for containing pyrrolizidine alkaloids, which are toxic to grazing cattle and other livestock causing considerable losses to agricultural revenue. Consequently, control of ragwort is obligatory by law in the UK, Ireland and Australia. Commonly used management practices to control ragwort include mechanical removal, grazing, pasture management, biological control and chemical control. In this review the biology of ragwort species is shortly described and the different management practices are discussed

Flushing Ewes on Chemically Cured Hill Pastures

A study was conducted to evaluate the use of chemically cured pasture as a flushing feed for ewes in western Oregon. In 1976 paraquat (0.28 kg/ha) was used to chemically cure hill pasture forage when perennial ryegrass (Lolium perenne L.) and tall fescue (Festuca arundinacea Schreb.) were in early anthesis. Crossbred ewes grazed the pastures from 17 days after the start of mating. Forage available during the breeding season had a higher protein content (P<.50) on paraquat-treated than on untreated pasture. Paraquat treatment had no effect, however on forage dry matter digestibility (P<.05). Chemical curing greatly reduced herbage yield, probably due to increased shattering and decomposition losses. Summer rainfall may have intensified the latter problem. Using chemically cured forage as flushing feed did not improve ewe live weight gains or lambing performance over untreated forage. Therefore, flushing ewes on chemically cured pasture appears to have little potential in areas, such as western Oregon, where summer rainfall is likely to occur.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

A Simple, Lightweight Point Frame

A simple, lightweight, yet rugged point frame is described. This frame can be easily constructed at a relatively low cost (1975 cost of materials=$6.00 per frame).This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Plant response to defoliation in a subalpine green fescue community

This study was prompted by concerns that expansion of elk (Cervus canadensus) ranges upward into subalpine grasslands might be damaging green fescue (Festuca viridula Vasey) meadows in Mount Rainier National Park. Objectives of the study were to examine effects of season and intensity of defoliation on phytomass productivity and canopy cover of these subalpine dry meadows and to relate these observations to the degree of elk utilization actually occurring on 3 representative meadows. Grazing in all meadows was very light. Less than one half of the plants examined showed any evidence of having been grazed. Plants which were grazed typically had less than 15% of their tops removed. Only green fescue was grazed to any significant extent by elk. Defoliation treatments (0%, 25%, 50%, and 75% of aerial phytomass removed in either early-, mid-, or late-season 1986 and again in 1987) had little effect upon plant cover the following year. Total herbage production was greater for defoliated than for undefoliated control plots in 1987, but did not vary with season of defoliation. Reproduction of green fescue and Lupinus latifolius Agardh. tended to decline as defoliation intensity increased in 1987. Neither season nor intensity of defoliation affected any of the parameters measured in 1988, a year of very low plant production. Green fescue subalpine grasslands appear to be quite tolerant of defoliation. All treatment effects were small relative to yearly differences induced by climatic variation.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202