9,383 research outputs found

    Conservation of Arabidopsis thaliana photoperiodic flowering time genes in onion (Allium cepa L.)

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    The genetics underlying onion development is poorly understood. Here the characterisation of onion homologues of Arabidopsis photoperiodic flowering pathway genes is reported with the end goal of accelerating onion breeding programmes by understanding the genetic basis of adaptation to different latitudes. The expression of onion GI, FKF1 and ZTL homologues under SD and LD conditions was examined using quantitative RT-PCR. The expression of AcGI and AcFKF1 was examined in onion varieties which exhibit different daylength responses. Phylogenetic trees were constructed to confirm the identity of the homologues. AcGI and AcFKF1 showed diurnal expression patterns similar to their Arabidopsis counterparts while AcZTL was found to be constitutively expressed. AcGI showed similar expression patterns in varieties which exhibit different daylength responses whereas AcFKF1 showed differences. It is proposed that these differences could contribute to the different daylength responses in these varieties. Phylogenetic analyses showed that all the genes isolated are very closely related to their proposed homologues. The results presented here show that key genes controlling photoperiodic flowering in Arabidopsis are conserved in onion and a role for these genes in the photoperiodic control of bulb initiation is predicted. This theory is supported by expression and phylogenetic data

    Using the Man9(GlcNAc)2 – DC-SIGN pairing to probe specificity in photochemical immobilization

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    We demonstrate the expected preference of an immobilised oligosaccharide Man(9)(GlcNAc)(2) upon a 96-well photochemical array, for its known receptor, the cell-surface lectin Dendritic Cell-Specific ICAM3 Grabbing Nonintegrin (DC-SIGN) when compared to immobilised competing monosaccharides

    Unexpected evolutionary proximity of eukaryotic and cyanobacterial enzymes responsible for biosynthesis of retinoic acid and its oxidation

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    Biosynthesis of retinoic acid from retinaldehyde (retinal) is catalysed by an aldehyde dehydrogenase (ALDH) and its oxidation by cytochrome P450 enzymes (CYPs). Herein we show by phylogenetic analysis that the ALDHs and CYPs in the retinoic acid pathway in animals are much closer in evolutionary terms to cyanobacterial orthologs than would be expected from the standard models of evolution

    A Model for the Genesis of Arterial Pressure Mayer Waves from Heart Rate and Sympathetic Activity

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    Both theoretic models and cross-spectral analyses suggest that an oscillating sympathetic nervous outflow generates the low frequency arterial pressure fluctuations termed Mayer waves. Fluctuations in heart rate also have been suggested to relate closely to Mayer waves, but empiric models have not assessed the joint causative influences of hemt rate and sympathetic activity. Therefore, we constructed a model based simply upon the hemodynamic equation deriving from Ohm's Law. With this model, we determined time relations and relative contributions of heart rate and sympathetic activity to the genesis of arterial pressure Mayer waves. We assessed data from eight healthy young volunteers in the basal state and in a high sympathetic state known to produce concurrent increases in sympathetic nervous outflow and Mayer wave amplitude. We fit the Mayer waves (0.05-0.20 Hz) in mean arterial pressure by the weighted sum ofleading oscillations in heart rate and sympathetic nerve activity. This model of our data showed heart rate oscillations leading by 2-3.75 seconds were responsible for almost half of the variance in arterial pressure (basal R^2=0.435±0.140, high sympathetic R^2=0.438±0.180). Surprisingly, sympathetic activity (lead 0-5 seconds) contributed only modestly to the explained variance in Mayer waves during either sympathetic state (basal: ∆R^2=0.046±0.026; heightened: ∆R^2=0.085±0.036). Thus, it appears that heart rate oscillations contribute to Mayer waves in a simple linear fashion, whereas sympathetic fluctuations contribute little to Mayer waves in this way. Although these results do not exclude an important vascular sympathetic role, they do suggest that additional Ji1ctors, such as sympathetic transduction into vascular resistance, modulate its influence.Binda and Fred Shuman Foundation; National Institute on Aging (AG14376)

    A Model for the Genesis of Arterial Pressure Mayer Waves from Heart Rate and Sympathetic Activity

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    Both theoretic models and cross-spectral analyses suggest that an oscillating sympathetic nervous outflow generates the low frequency arterial pressure fluctuations termed Mayer waves. Fluctuations in heart rate also have been suggested to relate closely to Mayer waves, but empiric models have not assessed the joint causative influences of hemt rate and sympathetic activity. Therefore, we constructed a model based simply upon the hemodynamic equation deriving from Ohm's Law. With this model, we determined time relations and relative contributions of heart rate and sympathetic activity to the genesis of arterial pressure Mayer waves. We assessed data from eight healthy young volunteers in the basal state and in a high sympathetic state known to produce concurrent increases in sympathetic nervous outflow and Mayer wave amplitude. We fit the Mayer waves (0.05-0.20 Hz) in mean arterial pressure by the weighted sum ofleading oscillations in heart rate and sympathetic nerve activity. This model of our data showed heart rate oscillations leading by 2-3.75 seconds were responsible for almost half of the variance in arterial pressure (basal R^2=0.435±0.140, high sympathetic R^2=0.438±0.180). Surprisingly, sympathetic activity (lead 0-5 seconds) contributed only modestly to the explained variance in Mayer waves during either sympathetic state (basal: ∆R^2=0.046±0.026; heightened: ∆R^2=0.085±0.036). Thus, it appears that heart rate oscillations contribute to Mayer waves in a simple linear fashion, whereas sympathetic fluctuations contribute little to Mayer waves in this way. Although these results do not exclude an important vascular sympathetic role, they do suggest that additional Ji1ctors, such as sympathetic transduction into vascular resistance, modulate its influence.Binda and Fred Shuman Foundation; National Institute on Aging (AG14376)

    Economic Impacts of the Elimination of Azinphos-methyl on the Apple Industry and Washington State

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    The Environmental Protection Agency has declared the organophosphate pesticide azinphos-methyl (AZM) cannot be used in the production of apples after September 30, 2012. We estimate the change to sales, price, and employment to the Washington State apple industry from using the likely AZM alternative had this ban been in effect in 2007. Furthermore, we estimate the effects of this ban as it ripples through the overall Washington State economy. We find the ban will bring a relatively modest change to sales (-0.8%), prices (0.2%), and employment (0.1%) in the apple industry, with negligible impacts on the overall Washington State economy.apples, azinphos-methyl, economic impact, computable general equilibrium

    The Ecological and Civil Mainsprings of Property: An Experimental Economic History of Whalers’ Rules of Capture

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    This paper uses a laboratory experiment to probe the proposition that property emerges anarchically out of social custom. We test the hypothesis that whalers in the 18th and 19th century developed rules of conduct that minimized the sum of the transaction and production costs of capturing their prey, the primary implication being that different ecological conditions lead to different rules of capture. Holding everything else constant, we find that simply imposing two different types of prey is insufficient to observe two different rules of capture. Another factor is essential, namely that the members of the community are civil-minded.property rights, endogenous rules, whaling, experimental economics

    Personalized medicine : the impact on chemistry

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    An effective strategy for personalized medicine requires a major conceptual change in the development and application of therapeutics. In this article, we argue that further advances in this field should be made with reference to another conceptual shift, that of network pharmacology. We examine the intersection of personalized medicine and network pharmacology to identify strategies for the development of personalized therapies that are fully informed by network pharmacology concepts. This provides a framework for discussion of the impact personalized medicine will have on chemistry in terms of drug discovery, formulation and delivery, the adaptations and changes in ideology required and the contribution chemistry is already making. New ways of conceptualizing chemistry’s relationship with medicine will lead to new approaches to drug discovery and hold promise of delivering safer and more effective therapies
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