2,409 research outputs found

    Seven-fluorochrome mouse M-FISH for high-resolution analysis of interchromosomal rearrangements

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    The mouse has evolved to be the primary mammalian genetic model organism. Important applications include the modeling of human cancer and cloning experiments. In both settings, a detailed analysis of the mouse genome is essential. Multicolor karyotyping technologies have emerged to be invaluable tools for the identification of mouse chromosomes and for the deciphering of complex rearrangements. With the increasing use of these multicolor technologies resolution limits are critical. However, the traditionally used probe sets, which employ 5 different fluorochromes, have significant limitations. Here, we introduce an improved labeling strategy. Using 7 fluorochromes we increased the sensitivity for the detection of small interchromosomal rearrangements (700 kb or less) to virtually 100%. Our approach should be important to unravel small interchromosomal rearrangements in mouse models for DNA repair defects and chromosomal instability. Copyright (C) 2003 S. Karger AG, Basel

    The Efficacy of Four Sunburn Mitigation Strategies and Their Effects on Yield, Fruit Quality, and Economic Performance of Honeycrisp Cv. Apples under Eastern New York (USA) Climatic Conditions

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    Sunburn is a serious economic problem in practically all apple-growing regions of the world. Losses of apple fruit due to sunburn can range from 10% as high as 50%. Several years ago, this problem started to be a concern in Eastern New York State, especially in the Hudson Valley region with the cultivar ‘Honeycrisp’. The study was conducted in three ‘Honeycrisp’ apple tree orchards in the Hudson Valley region (Southeast, New York State) during the 2015 and 2016 growing seasons. Four sunburn mitigation strategies were tested (evaporative cooling, 20% crystal net, the sunscreen Raynox Plus¼ and the particle film ScreenDuo¼) at a variety of timings throughout each growing season. Yield, sunburn incidence/severity, quality, and economic returns were evaluated. Treatments did not affect horticulture performance and fruit quality, but they did reduce sunburn damage to varying degrees. The greatest sunburn mitigation was achieved with the use of netting, followed by spray applications of Raynox Plus¼ and ScreenDuo¼. Apples with sunburn damage had higher flesh firmness, soluble solids content and titratable acidity. Treatment differences in sunburn mitigation did not result in higher net returns to the grower.info:eu-repo/semantics/acceptedVersio

    Temperature Dependence of Fast and Slow Gating Relaxations of ClC-0 Chloride Channels

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    The chloride channel from the Torpedo electric organ, ClC-0, is the best studied member of a large gene-family (Jentsch, T.J. 1996. Curr. Opin. Neurobiol. 6:303–310.). We investigate the temperature dependence of both the voltage- and chloride-dependent fast gate and of the slow gate of the “double-barreled” ClC-0 expressed in Xenopus oocytes. Kinetics of the fast gate exhibit only a moderate temperature dependence with a Q10 of 2.2. Steady-state popen of the fast gate is relatively independent of temperature. The slow gate, in contrast, is highly temperature sensitive. Deactivation kinetics at positive voltages are associated with a Q10 of ∌40. Steady-state open probability of the slow gate (popenslow(V)) can be described by a Boltzmann distribution with an apparent gating valence of ≈2 and a variable “offset” at positive voltages. We note a positive correlation of this offset (i.e., the fraction of channels that are not closed by the slow gate) with the amount of expression. This offset is also highly temperature sensitive, being drastically decreased at high temperatures. Paradoxically, the maximum degree of activation of the slow gate also decreases at higher temperatures. The strong temperature dependence of the slow gate was also observed at the single channel level in inside-out patches. The results imply that within a Markovian-type description at least two open and two closed states are needed to describe slow gating. The strong temperature dependence of the slow gate explains the phenotype of several ClC-0 point-mutants described recently by Ludewig et al. (Ludewig, U., T.J. Jentsch, and M. Pusch. 1996. J. Physiol. (Lond.). In press). The large Q10 of slow gating kinetics points to a complex rearrangement. This, together with the correlation of the fraction of noninactivating channels with the amount of expression and the fact that the slow gate closes both protochannels simultaneously suggests that the slow gate is coupled to subunit interaction of the multimeric ClC-0 channel

    Versatile compact atomic source for high resolution dual atom interferometry

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    We present a compact 87^{87}Rb atomic source for high precision dual atom interferometers. The source is based on a double-stage magneto-optical trap (MOT) design, consisting of a 2-dimensional (2D)-MOT for efficient loading of a 3D-MOT. The accumulated atoms are precisely launched in a horizontal moving molasses. Our setup generates a high atomic flux (>1010>10^{10} atoms/s) with precise and flexibly tunable atomic trajectories as required for high resolution Sagnac atom interferometry. We characterize the performance of the source with respect to the relevant parameters of the launched atoms, i.e. temperature, absolute velocity and pointing, by utilizing time-of-flight techniques and velocity selective Raman transitions.Comment: uses revtex4, 9 pages, 12 figures, submitted to Phys. Rev.

    The INO80 Complex Removes H2A.Z to Promote Presynaptic Filament Formation during Homologous Recombination

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    The INO80 complex (INO80-C) is an evolutionarily conserved nucleosome remodeler that acts in transcription, replication, and genome stability. It is required for resistance against genotoxic agents and is involved in the repair of DNA double-strand breaks (DSBs) by homologous recombination (HR). However, the causes of the HR defect in INO80-C mutant cells are controversial. Here, we unite previous findings using a system to study HR with high spatial resolution in budding yeast. We find that INO80-C has at least two distinct functions during HR-DNA end resection and presynaptic filament formation. Importantly, the second function is linked to the histone variant H2A.Z. In the absence of H2A.Z, presynaptic filament formation and HR are restored in INO80-C-deficient mutants, suggesting that presynaptic filament formation is the crucial INO80-C function during HR

    Inhibition of the norepinephrine transporter improves behavioral flexibility in rats and monkeys

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    RationalePoor cognitive control, including reversal learning deficits, has been reported in children with attention deficit hyperactivity disorder, in stimulant-dependent humans, and in animal models of these disorders; these conditions have each been associated with abnormal catecholaminergic function within the prefrontal cortex.ObjectivesIn the current studies, we sought to explore how elevations in extracellular catecholamine levels, produced by pharmacological inhibition of catecholamine reuptake proteins, affect behavioral flexibility in rats and monkeys.Materials and methodsAdult male Long-Evans rats and vervet monkeys were trained, respectively, on a four-position discrimination task or a three-choice visual discrimination task. Following systemic administration of pharmacological inhibitors of the dopamine and/or norepinephrine membrane transporters, rats and monkeys were exposed to retention or reversal of acquired discriminations.ResultsIn accordance with our a priori hypothesis, we found that drugs that inhibit norepinephrine transporters, such as methylphenidate, atomoxetine, and desipramine, improved reversal performance in rats and monkeys; this was mainly due to a decrease in the number of perseverative errors. Interestingly, the mixed dopamine and norepinephrine transporters inhibitor methylphenidate, if anything, impaired performance during retention in both rats and monkeys, while administration of the selective dopamine transporter inhibitor GBR-12909 increased premature responses but did not alter reversal learning performance.ConclusionsOur results suggest that pharmacological inhibition of the membrane norepinephrine, but not membrane dopamine, transporter is associated with enhanced behavioral flexibility. These data, combined with earlier reports, may indicate that enhanced extracellular catecholamine levels in cortical regions, secondary to norepinephrine reuptake inhibition, improves multiple aspects of inhibitory control over responding in rats and monkeys

    Generating near-extreme Summer Reference Years (SRY) for building performance simulation

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    Copyright © 2015 by SAGE PublicationsAt present there is no universally accepted method for deriving near-extreme summer weather data for building performance simulation. Existing datasets such as the Design Summer Years (DSY) used in the United Kingdom (UK) to estimate summer discomfort in naturally ventilated and free running buildings have been criticised for being inconsistent with the corresponding Test Reference Years (TRY). This paper proposes a method for generating Summer Reference Years (SRY) by adjusting the TRY of a given site with meteorological data in order to represent near-extreme conditions. It takes as the starting point that the TRY is robust, being determined on a monthly basis from the most typical months. Initial simulations for the 14 UK TRY locations show promising results for determining building overheating with the SRY

    Long Term Observation of the Grassland Vegetation Used Intensively or Extensively and Ecologically

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    The aim of the present paper was to study alterations of the grassland flora from 55 plots following a more extensive management under long term observation within 6 years. Extensification of grassland use leads to an increase of the numbers of plant species by 32%, “Red-list-species” included. The moisture number of the soils slightly increased and the reaction and nitrogen numbers decreased. Results are presented for different vegetation units
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