1,372 research outputs found

    Trade-offs between personal immunity and reproduction in the burying beetle, N. vespilloides

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    We know that parental investment and immune investment are costly processes, but it is unclear which trait will be prioritised when both may be required. Here we address this question using the burying beetle Nicrophorus vespilloides, carrion breeders that exhibit biparental care of young. Our results show that immunosuppression occurs during provision of parental care. We measured Phenoloxidase (PO) on Day 1-8 of the breeding bout and results show a clear decrease in PO immediately from presentation of the breeding resource onwards. Having established baseline immune investment during breeding we then manipulated immune investment at different times by applying a wounding challenge. Beetles were wounded prior to and during the parental care period and reproductive investment quantified. Different effects on reproductive output occur depending on the timing of wounding. Challenging the immune system with wounding prior to breeding does not affect reproductive output and subsequent Lifetime Reproductive Success (LRS). LRS is also unaffected by applying an immune elicitor prior to breeding, though different arms of the immune system are up/downregulated, perhaps indicating a trade-off between cellular and humoral immunity. In contrast, wounding during breeding reduces reproductive output and to the greatest extent if the challenge is applied early in the breeding bout. Despite being immunosuppressed, breeding beetles can still respond to wounding by increasing PO, albeit not to pre-breeding levels. This upregulation of PO during breeding may affect parental investment, resulting in a reduction in reproductive output. The potential role of juvenile hormone in controlling this trade-off is discussed

    A research-inspired laboratory sequence investigating acquired drug resistance

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    Here, we present a six-session laboratory exercise designed to introduce students to standard biochemical techniques in the context of investigating a high impact research topic, acquired resistance to the cancer drug Gleevec. Students express a Gleevec-resistant mutant of the Abelson tyrosine kinase domain, the active domain of an oncogenic protein implicated in chronic myelogenous leukemia, and investigate the kinase activity of wild type and mutant enzyme in the presence of two cancer drugs. Techniques covered include protein expression, purification, and gel analysis, kinase activity assays, and protein structure viewing. The exercises provide students with a hands-on understanding of the impact of biochemistry on human health, and demonstrate their potential as the next generation of investigators.Howard Hughes Medical Institut

    Is there evidence for export-led adoption of ISO 14001? A review of the literature using meta-regression

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    Does the export orientation of a firm affect the likelihood that it adopts an environmental management certification? We use meta-regression methods to analyze systematically the corpus of published research on export-led adoption of the largest and most prominent certification, ISO 14001. We show that the explanatory variables authors choose to include in their models reflect the tenets of stakeholder and institutional theories. We also find that the literature suffers from substantial publication bias but that, once this is accounted for appropriately, a genuine effect remains. The evidence from 20 years of published studies taken as a whole is that export does incentivize the adoption of the standard as often hypothesized by proponents of voluntary approaches and self-regulation

    N fertilizer and harvest impacts on bioenergy crop contributions to SOC

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    Below ground root biomass is infrequently measured and simply represented in models that predict landscape level changes to soil carbon stocks and greenhouse gas balances. Yet, crop-specific responses to N fertilizer and harvest treatments are known to impact both plant allocation and tissue chemistry, potentially altering decomposition rates and the direction and magnitude of soil C stock changes and greenhouse gas fluxes. We examined switchgrass (Panicum virgatum L.) and corn (Zea mays L.,) yields, below ground root biomass, C, N and soil particulate organic matter-C (POM-C) in a 9-year rain fed study of N fertilizer rate (0, 60, 120 and 180 kg N ha-1) and harvest management near Mead, NE, USA. Switchgrass was harvested with one pass in either August or postfrost, and for no-till (NT) corn, either 50% or no stover was removed. Switchgrass had greater below ground root biomass C and N (6.39, 0.10 Mg ha-1) throughout the soil profile compared to NT-corn (1.30, 0.06 Mg ha-1) and a higher below ground root biomass C:N ratio, indicating greater recalcitrant below ground root biomass C input beneath switchgrass. There was little difference between the two crops in soil POM-C indicating substantially slower decomposition and incorporation into SOC under switchgrass, despite much greater root C. The highest N rate decreased POM-C under both NT-corn and switchgrass, indicating faster decomposition rates with added fertilizer. Residue removal reduced corn below ground root biomass C by 37% and N by 48% and subsequently reduced POM-C by 22% compared to no-residue removal. Developing productive bioenergy systems that also conserve the soil resource will require balancing fertilization that maximizes above ground productivity but potentially reduces SOC sequestration by reducing below ground root biomass and increasing root and soil C decomposition

    N fertilizer and harvest impacts on bioenergy crop contributions to SOC

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    Below ground root biomass is infrequently measured and simply represented in models that predict landscape level changes to soil carbon stocks and greenhouse gas balances. Yet, crop-specific responses to N fertilizer and harvest treatments are known to impact both plant allocation and tissue chemistry, potentially altering decomposition rates and the direction and magnitude of soil C stock changes and greenhouse gas fluxes. We examined switchgrass (Panicum virgatum L.) and corn (Zea mays L.,) yields, below ground root biomass, C, N and soil particulate organic matter-C (POM-C) in a 9-year rain fed study of N fertilizer rate (0, 60, 120 and 180 kg N ha-1) and harvest management near Mead, NE, USA. Switchgrass was harvested with one pass in either August or postfrost, and for no-till (NT) corn, either 50% or no stover was removed. Switchgrass had greater below ground root biomass C and N (6.39, 0.10 Mg ha-1) throughout the soil profile compared to NT-corn (1.30, 0.06 Mg ha-1) and a higher below ground root biomass C:N ratio, indicating greater recalcitrant below ground root biomass C input beneath switchgrass. There was little difference between the two crops in soil POM-C indicating substantially slower decomposition and incorporation into SOC under switchgrass, despite much greater root C. The highest N rate decreased POM-C under both NT-corn and switchgrass, indicating faster decomposition rates with added fertilizer. Residue removal reduced corn below ground root biomass C by 37% and N by 48% and subsequently reduced POM-C by 22% compared to no-residue removal. Developing productive bioenergy systems that also conserve the soil resource will require balancing fertilization that maximizes above ground productivity but potentially reduces SOC sequestration by reducing below ground root biomass and increasing root and soil C decomposition

    Synthesis of tri- and tetramines containing two 2,3-dihydroxypyrrolidine moieties and their inhibitory activity toward α-mannosidases

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    Through the reductive amination of N-[(tert-butoxy)carbonyl]-2,5-dideoxy-2,5-imino-3,4-Oisopropylidene-L-ribose with tetramethylenediamine, hexamethylenediamine, 2,7- diaminofluorene, 4,4'-diaminodiphenylmethane and 1,4-(diaminomethyl)benzene, five tetramines containing two (2R,3R,4S)-2-aminomethylpyrrolidine-3,4-diol moieties have been prepared and assayed for their inhibitory activities toward 24 glycosidases. Tetramines containing the tetramethylene or benzene-1,4-dimethylene linkers are more potent αmannosidase inhibitors than simple (2R,3R,4S)-2-aminomethylpyrrolidine-3,4-diols. Triamines such as (2S,3R,4S)-bis(3,4-dihydroxy-pyrrolidin-2-ethyl)amine were also prepared and shown to be better α-mannosidase inhibitors than (2S,3R,4S)-2-(2-aminoethyl)pyrrolidin-3,4-diol.The Swiss National Science Foundation (grants n° 20-63667.00 and 2100-063567.00/1)European COST (COST D13/0001/99) programOffice Fédéral de l'Education et de la Science (Bern)Dirección General de Investigación Científica y Técnica of Spain (grant n° BQU-2001-3779)SOCRATES (EPFL/Sevilla) progra

    Synthesis of tri- and tetramines containing two 2,3-dihydroxypyrrolidine moieties and their inhibitory activity toward α-mannosidases

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    Through the reductive amination of N-[(tert-butoxy)carbonyl]-2,5-dideoxy-2, 5-imino-3,4-O-isopropylidene-L-ribose with tetramethylenediamine, hexamethylenediamine, 2,7-diaminofluorene, 4,4′-diaminodiphenylmethane and 1,4-(diaminomethyl)benzene, five tetramines containing two (2R,3R,4S)-2- aminomethylpyrrolidine-3,4-diol moieties have been prepared and assayed for their inhibitory activities toward 24 glycosidases. Tetramines containing the tetramethylene or benzene-1,4-dimethylene linkers are more potent α-mannosidase inhibitors than simple (2R,3R,4S)-2-aminomethylpyrrolidine- 3,4-diols. Triamines such as (2S,3R,4S)-bis(3,4-dihydroxy-pyrrolidin-2-ethyl) amine were also prepared and shown to be better α-mannosidase inhibitors than (2S,3R,4S)-2-(2-aminoethyl)pyrrolidin-3,4-diol

    Psychological test usage in duchenne muscular dystrophy: An EU multi-centre study

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    Aim: During the last two decades brain related comorbidities of Duchenne have received growing scientific and clinical interest and therefore systematic assessment of cognition, behaviour and learning is important. This study aims to describe the instruments currently being used in five neuromuscular clinics in Europe as well as the diagnoses being made in these clinics. Method: A Delphi based procedure was developed by which a questionnaire was sent to the psychologist in five of the seven participating clinics of the Brain Involvement In Dystrophinopathy (BIND) study. Instruments and diagnoses being used were inventoried for three domains of functioning (cognition, behaviour and academics) and three age groups (3–5 years, 6–18 years and adulthood 18+ years). Results: Data show wide diversity of tests being used in the five centres at different age groups and different domains. For the intelligence testing there is consensus in using the Wechsler scales, but all other domains such as memory, attention, behavioural problems and reading are tested in very different ways by different instruments in the participating centres. Conclusion: The heterogeneity of tests and diagnoses being used in current clinical practice underlines the importance for developing a Standard Operating Procedure (SOP) to improve both clinical practice and scientific research over different countries and improve comparative work

    Over winter microbial processes in a Svalbard snow pack:an experimental approach

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    International audienceSnow packs cover large expanses of Earth’s land surface, making them integral components of the cryosphere in terms of past climate and atmospheric proxies, surface albedo regulators, insulators for other Arctic environments and habitats for diverse microbial communities such as algae, bacteria and fungi. Yet, most of our current understanding of snow pack environments, specifically microbial activity and community interaction, is limited to the main microbial growing season during spring ablation. At present, little is known about microbial activity and its influence on nutrient cycling during the subfreezing temperatures and 24-h darkness of the polar winter. Here, we examined microbial dynamics in a simulated cold (−5°C), dark snow pack to determine polar winter season microbial activity and its dependence on critical nutrients. Snow collected from Ny-Ålesund, Svalbard was incubated in the dark over a 5-week period with four different nutrient additions, including glacial mineral particles, dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP) and a combined treatment of DIN plus DIP. Data indicate a consumption of dissolved inorganic nutrients, particularly DIN, by heterotrophic communities, suggesting a potential nitrogen limitation, contradictory to phosphorus limitations found in most aquatic environments. 16S amplicon sequencing also reveal a clear difference in microbial community composition in the particulate mineral treatment compared to dissolved nutrient treatments and controls, suggesting that certain species of heterotrophs living within the snow pack are more likely to associate with particulates. Particulate phosphorus analyses indicate a potential ability of heterotrophic communities to access particulate sources of phosphorous, possibly explaining the lack of phosphorus limitation. These findings have importance for understanding microbial activity during the polar winter season and its potential influences on the abundance and bioavailability of nutrients released to surface ice and downstream environments during the ablation season
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