108 research outputs found

    Recovery of Yearling Calves from Fescue Toxicosis

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    Tall fescue (Lolium arundinaceum (Schreb.) S.J. Darbyshire) is widely utilized for grazing in the transition zone between the temperate and subtropical regions of the eastern U.S.A. Cattle grazing tall fescue frequently exhibit fescue toxicosis, a malady caused by consumption of toxins produced by the endophyte, Neotyphodium coenophialum. Symptoms of fescue toxicosis include retention of rough hair coat, increased body temperature and laboured respiration. Heat stress may be severe at onset of high ambient temperature and humidity. Transporting cattle exhibiting toxicosis can therefore be difficult because combined stresses of the toxicosis and transporting often result in high mortality. An experiment was conducted to measure trends in rectal temperatures for yearling steers following removal from tall fescue and placement on a fescue-free diet

    Novel links between ciliopathies and FGF-related craniofacial syndromes

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    K Liu1*, JT Tabler1, HL Szabo-Rogers1, A Mesbahi1, C Healy1, W Barrell1, B Wlodarczyk2, Author Affiliations 1 King's College London, UK 2 University of Texas Southwestern, USA 3 University of Texas at Austin, USAOral Presentation : Recent studies suggest that planar cell polarity (PCP) genes coordinate cell polarity, ciliogenesis and signalling during mammalian development. FUZ is a PCP gene implicated in human congenital anomalies, including neural tube defects and orofacial clefting. Our analysis of fuzzy mutant mice reveals ciliogenesis defects in craniofacial tissues as well as a suite of phenotypes reminiscent of FGF-related craniofacial disorders. Mutants have coronal synostosis, shortened facial extensions, low-set ears and a high-arched palate. To our surprise, we found that the facial defects are due to increased neural crest migration into the first branchial arch (BA1), resulting in maxillary hyperplasia. Furthermore, the neural crest cells migrate in a disorganized fashion, deeper than normal and with fewer cell-cell contacts. This ectopic migration correlates with a dramatic increase in FGF signaling, first in the mid-hindbrain boundary, and then in the BA1 epithelia. The increased tissue causes a medial positional shift in the palatal primordia that manifests as a high-arched palate with pseudo-cleft. Genetic loss of fgf8 rescues the maxillary hyperplasia. Taken together, our data suggest a novel interplay between ciliogenesis, FGF signalling and migration of neural crest which may underlie congenital craniofacial dysmorphologies.Molecular [email protected]

    Classification and comparison of snow fences for the protection of transport infrastructures

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    Blowing snow or sand transport generates serious problems such as transport infrastructures buried under snow or sand in many parts of the world. Some of the most important problems that snow and sand storms can cause include drivers getting trapped on the roads, traffic being held up indefinitely, accidents occurring and populations being isolated. Snow fences provide a solution to this problem as they can hold back the snow, preventing displacement and wind-induced drifting. In this way, they reduce these problems on transport infrastructures and improve visibility, providing safer driving conditions. In this review, a classification is proposed of snow fences based on three basic types: earth, structural and living snow fences. Among the structural ones, non-porous and porous snow fences are distinguished. The different possibilities in terms of the placement of snow fences are also analyzed. Finally, different types of snow fences have been compared under design, construction and operation criteria. This review can provide initial guidelines for technicians to choose the best snow fence for blizzard conditions

    Effects of climate and snow depth on Bromus tectorum population dynamics at high elevation

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    Invasive plants are thought to be especially capable of range shifts or expansion in response to climate change due to high dispersal and colonization abilities. Although highly invasive throughout the Intermountain West, the presence and impact of the grass Bromus tectorum has been limited at higher elevations in the eastern Sierra Nevada, potentially due to extreme wintertime conditions. However, climate models project an upward elevational shift of climate regimes in the Sierra Nevada that could favor B. tectorum expansion. This research specifically examined the effects of experimental snow depth manipulations and interannual climate variability over 5 years on B. tectorum populations at high elevation (2,175 m). Experimentally-increased snow depth had an effect on phenology and biomass, but no effect on individual fecundity. Instead an experimentally-increased snowpack inhibited population growth in 1 year by reducing seedling emergence and early survival. A similar negative effect of increased snow was observed 2 years later. However, a strong negative effect on B. tectorum was also associated with a naturally low-snow winter, when seedling emergence was reduced by 86%. Across 5 years, winters with greater snow cover and a slower accumulation of degree-days coincided with higher B. tectorum seedling density and population growth. Thus, we observed negative effects associated with both experimentally-increased and naturally-decreased snowpacks. It is likely that the effect of snow at high elevation is nonlinear and differs from lower elevations where wintertime germination can be favorable. Additionally, we observed a doubling of population size in 1 year, which is alarming at this elevation

    Molecular and cellular mechanisms underlying the evolution of form and function in the amniote jaw.

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    The amniote jaw complex is a remarkable amalgamation of derivatives from distinct embryonic cell lineages. During development, the cells in these lineages experience concerted movements, migrations, and signaling interactions that take them from their initial origins to their final destinations and imbue their derivatives with aspects of form including their axial orientation, anatomical identity, size, and shape. Perturbations along the way can produce defects and disease, but also generate the variation necessary for jaw evolution and adaptation. We focus on molecular and cellular mechanisms that regulate form in the amniote jaw complex, and that enable structural and functional integration. Special emphasis is placed on the role of cranial neural crest mesenchyme (NCM) during the species-specific patterning of bone, cartilage, tendon, muscle, and other jaw tissues. We also address the effects of biomechanical forces during jaw development and discuss ways in which certain molecular and cellular responses add adaptive and evolutionary plasticity to jaw morphology. Overall, we highlight how variation in molecular and cellular programs can promote the phenomenal diversity and functional morphology achieved during amniote jaw evolution or lead to the range of jaw defects and disease that affect the human condition

    Insight on genes affecting tuber development in potato upon <i>Potato spindle tuber viroid</i> (PSTVd) infection

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    Potato (Solanum tuberosum L) is a natural host of Potato spindle tuber viroid (PSTVd) which can cause characteristic symptoms on developing plants including stunting phenotype and distortion of leaves and tubers. PSTVd is the type species of the family Pospiviroidae, and can replicate in the nucleus and move systemically throughout the plant. It is not well understood how the viroid can affect host genes for successful invasion and which genes show altered expression levels upon infection. Our primary focus in this study is the identification of genes which can affect tuber formation since viroid infection can strongly influence tuber development and especially tuber shape. In this study, we used a large-scale method to identify differentially expressed genes in potato. We have identified defence, stress and sugar metabolism related genes having altered expression levels upon infection. Additionally, hormone pathway related genes showed significant up- or down-regulation. DWARF1/DIMINUTO, Gibberellin 7-oxidase and BEL5 transcripts were identified and validated showing differential expression in viroid infected tissues. Our study suggests that gibberellin and brassinosteroid pathways have a possible role in tuber development upon PSTVd infection

    Impact of intra- versus inter-annual snow depth variation on water relations and photosynthesis for two Great Basin Desert shrubs

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    Snowfall provides the majority of soil water in certain ecosystems of North America. We tested the hypothesis that snow depth variation affects soil water content, which in turn drives water potential (Ψ) and photosynthesis, over 10 years for two widespread shrubs of the western USA. Stem Ψ (Ψ stem) and photosynthetic gas exchange [stomatal conductance to water vapor (g s), and CO2 assimilation (A)] were measured in mid-June each year from 2004 to 2013 for Artemisia tridentata var. vaseyana (Asteraceae) and Purshia tridentata (Rosaceae). Snow fences were used to create increased or decreased snow depth plots. Snow depth on +snow plots was about twice that of ambient plots in most years, and 20 % lower on -snow plots, consistent with several down-scaled climate model projections. Maximal soil water content at 40- and 100-cm depths was correlated with February snow depth. For both species, multivariate ANOVA (MANOVA) showed that Ψ stem, g s, and A were significantly affected by intra-annual variation in snow depth. Within years, MANOVA showed that only A was significantly affected by spatial snow depth treatments for A. tridentata, and Ψ stem was significantly affected by snow depth for P. tridentata. Results show that stem water relations and photosynthetic gas exchange for these two cold desert shrub species in mid-June were more affected by inter-annual variation in snow depth by comparison to within-year spatial variation in snow depth. The results highlight the potential importance of changes in inter-annual variation in snowfall for future shrub photosynthesis in the western Great Basin Desert

    Transgenesis in Animal Agriculture: Addressing Animal Health and Welfare Concerns

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    The US Food and Drug Administration’s final Guidance for Industry on the regulation of transgenesis in animal agriculture has paved the way for the commercialization of genetically engineered (GE) farm animals. The production-related diseases associated with extant breeding technologies are reviewed, as well as the predictable welfare consequences of continued emphasis on prolificacy at the potential expense of physical fitness. Areas in which biotechnology could be used to improve the welfare of animals while maintaining profitability are explored along with regulatory schema to improve agency integration in GE animal oversight
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