133 research outputs found

    Susceptibility of Myzus persicae, Brevicoryne brassicae and Nasonovia ribisnigri to fungal biopesticides in laboratory and field experiments

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    The aim of this study was to evaluate the potential of entomopathogenic fungi (EPF) for the control of aphid pests of field vegetable crops. Four biopesticides based on the EPF Beauveria bassiana (Botanigard ES and Naturalis L), Cordyceps fumosorosea s.l. (Preferal WG), and Akanthomyces dipterigenus (Vertalec) were evaluated in a laboratory bioassay against peach-potato aphid Myzus persicae, cabbage aphid Brevicoryne brassicae, and currant-lettuce aphid Nasonovia ribisnigri. There was significant variation in the spore dose provided by the products, with Botanigard ES producing the highest dose (639 viable spores per mm2). Botanigard ES also caused more mortality than the other products. Combining Vertalec with the vegetable oil-based adjuvant Addit had an additive effect on the mortality of B. brassicae. All fungal products reduced the number of progeny produced by M. persicae but there was no effect with B. brassicae or N. ribisnigri. When aphid nymphs were treated with Botanigard ES and Preferal WG, both products reduced population development, with up to 86% reduction occurring for Botanigard ES against M. persicae. In a field experiment, Botanigard ES sprayed twice, at seven-day intervals, against B. brassicae on cabbage plants, reduced aphid numbers by 73%. In a second field experiment with B. brassicae, M. persicae, and N. ribisnigri, Botanigard ES reduced populations of B. brassicae and N. ribisnigri but there was no significant effect on M. persicae

    Improving the availability of biopesticides : an interdisciplinary research project

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    There is a need for new, biologically-based crop protection products to serve as alternatives to or to complement synthetic chemical pesticides. An interdisciplinary research team from the natural and social sciences considered whether regulatory barriers were preventing more biopesticides reaching the market. The research coincided with a realisation by policy makers that more needed to be done to facilitate biopesticide registration, exemplified by the UK's Biopesticides Scheme. However, important differences remain between the UK and other countries such as the USA. Changes in regulatory arrangements need careful handling. The scientific work undertaken in the project provided a better understanding of the population biology of microbial control agents. Interdisciplinary work permitted a contribution to the policy debate

    A study of interface adhesion between polyamide 6 (PA6) and nitrile rubber (NBR)

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    This is the peer reviewed version of the following article: Wang Y., Ghita O., Kavanagh D., and Chandler D. (2014), A study of interface adhesion between polyamide 6 (PA6) and nitrile rubber (NBR), Surf. Interface Anal., 10-11, pages 1000–1004, which has been published in final form at 10.1002/sia.5488. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving: http://olabout.wiley.com/WileyCDA/Section/id-820227.html#termsThe mechanism of interface bonding of a selected nitrile rubber compound vulcanized on polyamide 6 was studied using transmission electron microscopy. The two types of interfaces identified were formed through mechanical clamping and enhanced by hydrogen bonding between polyamide 6 and silane coupling agent in nitrile rubber compoun

    Gene Expression Signature in Adipose Tissue of Acromegaly Patients.

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    To study the effect of chronic excess growth hormone on adipose tissue, we performed RNA sequencing in adipose tissue biopsies from patients with acromegaly (n = 7) or non-functioning pituitary adenomas (n = 11). The patients underwent clinical and metabolic profiling including assessment of HOMA-IR. Explants of adipose tissue were assayed ex vivo for lipolysis and ceramide levels. Patients with acromegaly had higher glucose, higher insulin levels and higher HOMA-IR score. We observed several previously reported transcriptional changes (IGF1, IGFBP3, CISH, SOCS2) that are known to be induced by GH/IGF-1 in liver but are also induced in adipose tissue. We also identified several novel transcriptional changes, some of which may be important for GH/IGF responses (PTPN3 and PTPN4) and the effects of acromegaly on growth and proliferation. Several differentially expressed transcripts may be important in GH/IGF-1-induced metabolic changes. Specifically, induction of LPL, ABHD5, and NRIP1 can contribute to enhanced lipolysis and may explain the elevated adipose tissue lipolysis in acromegalic patients. Higher expression of TCF7L2 and the fatty acid desaturases FADS1, FADS2 and SCD could contribute to insulin resistance. Ceramides were not different between the two groups. In summary, we have identified the acromegaly gene expression signature in human adipose tissue. The significance of altered expression of specific transcripts will enhance our understanding of the metabolic and proliferative changes associated with acromegaly

    A strong immune response in young adult honeybees masks their increased susceptibility to infection compared to older bees

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    Honeybees, Apis mellifera, show age-related division of labor in which young adults perform maintenance ("housekeeping") tasks inside the colony before switching to outside foraging at approximately 23 days old. Disease resistance is an important feature of honeybee biology, but little is known about the interaction of pathogens and age-related division of labor. We tested a hypothesis that older forager bees and younger "house" bees differ in susceptibility to infection. We coupled an infection bioassay with a functional analysis of gene expression in individual bees using a whole genome microarray. Forager bees treated with the entomopathogenic fungus Metarhizium anisopliae s.l. survived for significantly longer than house bees. This was concomitant with substantial differences in gene expression including genes associated with immune function. In house bees, infection was associated with differential expression of 35 candidate immune genes contrasted with differential expression of only two candidate immune genes in forager bees. For control bees (i.e. not treated with M. anisopliae) the development from the house to the forager stage was associated with differential expression of 49 candidate immune genes, including up-regulation of the antimicrobial peptide gene abaecin, plus major components of the Toll pathway, serine proteases, and serpins. We infer that reduced pathogen susceptibility in forager bees was associated with age-related activation of specific immune system pathways. Our findings contrast with the view that the immunocompetence in social insects declines with the onset of foraging as a result of a trade-off in the allocation of resources for foraging. The up-regulation of immune-related genes in young adult bees in response to M. anisopliae infection was an indicator of disease susceptibility; this also challenges previous research in social insects, in which an elevated immune status has been used as a marker of increased disease resistance and fitness without considering the effects of age-related development

    Boundary element methods for acoustic scattering by fractal screens

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    We study boundary element methods for time-harmonic scattering in R^n (n=2,3) by a fractal planar screen, assumed to be a non-empty bounded subset Gamma of the hyperplane Gamma_\infty=R^{n-1}\times \{0\}. We consider two distinct cases: (i) Gamma is a relatively open subset of Gamma_\infty with fractal boundary (e.g. the interior of the Koch snowflake in the case n=3); (ii) Gamma is a compact fractal subset of Gamma_\infty with empty interior (e.g. the Sierpinski triangle in the case n=3). In both cases our numerical simulation strategy involves approximating the fractal screen Gamma by a sequence of smoother "prefractal" screens, for which we compute the scattered field using boundary element methods that discretise the associated first kind boundary integral equations. We prove sufficient conditions on the mesh sizes guaranteeing convergence to the limiting fractal solution, using the framework of Mosco convergence. We also provide numerical examples illustrating our theoretical results

    Clinical Scholars: Using Program Evaluation to Inform Leadership Development

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    Leadership development programs are notoriously difficult to evaluate, and when evaluations are attempted, they often do not go beyond measuring low-level, short-term outcomes of the impacts experienced by participants. Many leadership development programs do not systematically assess changes that are catalyzed within the organizations, communities and systems in which participants lead. To address these challenges, evaluators of the Clinical Scholars National Leadership Institute (CNLI) have designed a comprehensive, mixed-methods evaluation approach to determine the effectiveness of the training and explore the impacts of participants in the spheres in which they lead. Guided by Michael Patton’s Developmental Evaluation approach and framed by Kirkpatrick’s Training Evaluation Model, the CSNLI evaluation collects data on multiple levels to provide a robust picture of the multiple outcomes of the program. The approach focuses on individual participant outcomes, by measuring competency changes over time and exploring how participants use the competencies gained through the training in their work. Social network analysis is utilized to measure the development and expansion of participants’ networks and collaboration within the teams, cohorts, and across sectors and disciplines throughout their time in the CSNLI. The Most Significant Change methodology and semi-structured alumni interviews are used to measure impacts participants identify as occurring as a result of their participation. Finally, Concept Mapping is implemented to explore how Fellows make meaning of the foundational concepts and values of the CSNLI. The outcome and impact evaluation activities employed by the CSNLI, in combination with quality improvement-focused process evaluation, support innovation and excellence in the provision of a health equity-grounded leadership development program

    Understanding Antibiotic Use in Companion Animals: A Literature Review Identifying Avenues for Future Efforts.

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    Addressing antibiotic use is essential to tackle antimicrobial resistance, a major human and animal health challenge. This review seeks to inform stewardship efforts in companion animals by collating research insights regarding antibiotic use in this group and identifying overlooked avenues for future research and stewardship efforts. The development of population-based methods has established that antibiotics are frequently used in companion animal care. Research insights are also contributing toward an in-depth comprehension of the contexts to antibiotic use. Qualitative approaches, for example, have enabled a nuanced understanding in four key areas: interactions with owners, clinical and financial risk management, time pressures, and clinic dynamics. This review identifies that much of the existing research frames antibiotic use as the result of choices made by the individuals at the interface of their use. Future research and policy endeavours could look beyond the moment of prescribing to consider the societal structures and networks in which companion animal antibiotic use is entangled. A diversification in research approaches and frameworks through which antibiotic use is understood will facilitate the identification of additional targets for stewardship initiatives beyond providing information and awareness campaigns

    Culture degeneration reduces sex-related gene expression, alters metabolite production and reduces insect pathogenic response in Cordyceps militaris

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    Cordyceps militaris is an entomopathogenic ascomycete, known primarily for infecting lepidopteran larval (caterpillars) and pupal hosts. Cordycepin, a secondary metabolite produced by this fungus has anti-inflammatory properties and other pharmacological activities. However, little is known about the biological role of this adenosine derivate and its stabilising compound pentostatin in the context of insect infection the life cycle of C. militaris. During repeated subcultivation under laboratory conditions a degeneration of C. militaris marked by decreasing levels of cordycepin production can occur. Here, using degenerated and parental control strains of an isolate of C. militaris, we found that lower cordycepin production coincides with the decline in the production of various other metabolites as well as the reduced expression of genes related to sexual development. Additionally, infection of Galleria mellonella (greater wax moth) caterpillars indicated that cordycepin inhibits the immune response in host haemocytes. Accordingly, the pathogenic response to the degenerated strain was reduced. These data indicate that there are simultaneous changes in sexual reproduction, secondary metabolite production, insect immunity and infection by C. militaris. This study may have implications for biological control of insect crop pests by fungi
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