70 research outputs found

    Whole Genome Resequencing Reveals Natural Target Site Preferences of Transposable Elements in Drosophila melanogaster

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    Transposable elements are mobile DNA sequences that integrate into host genomes using diverse mechanisms with varying degrees of target site specificity. While the target site preferences of some engineered transposable elements are well studied, the natural target preferences of most transposable elements are poorly characterized. Using population genomic resequencing data from 166 strains of Drosophila melanogaster, we identified over 8,000 new insertion sites not present in the reference genome sequence that we used to decode the natural target preferences of 22 families of transposable element in this species. We found that terminal inverted repeat transposon and long terminal repeat retrotransposon families present clade-specific target site duplications and target site sequence motifs. Additionally, we found that the sequence motifs at transposable element target sites are always palindromes that extend beyond the target site duplication. Our results demonstrate the utility of population genomics data for high-throughput inference of transposable element targeting preferences in the wild and establish general rules for terminal inverted repeat transposon and long terminal repeat retrotransposon target site selection in eukaryotic genomes

    An Ecological Alternative to Snodgrass & Vanderwart: 360 High Quality Colour Images with Norms for Seven Psycholinguistic Variables

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    This work presents a new set of 360 high quality colour images belonging to 23 semantic subcategories. Two hundred and thirty-six Spanish speakers named the items and also provided data from seven relevant psycholinguistic variables: age of acquisition, familiarity, manipulability, name agreement, typicality and visual complexity. Furthermore, we also present lexical frequency data derived from Internet search hits. Apart from the high number of variables evaluated, knowing that it affects the processing of stimuli, this new set presents important advantages over other similar image corpi: (a) this corpus presents a broad number of subcategories and images; for example, this will permit researchers to select stimuli of appropriate difficulty as required, (e.g., to deal with problems derived from ceiling effects); (b) the fact of using coloured stimuli provides a more realistic, ecologically-valid, representation of real life objects. In sum, this set of stimuli provides a useful tool for research on visual object-and word- processing, both in neurological patients and in healthy controls

    The Bank of Standardized Stimuli (BOSS), a New Set of 480 Normative Photos of Objects to Be Used as Visual Stimuli in Cognitive Research

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    There are currently stimuli with published norms available to study several psychological aspects of language and visual cognitions. Norms represent valuable information that can be used as experimental variables or systematically controlled to limit their potential influence on another experimental manipulation. The present work proposes 480 photo stimuli that have been normalized for name, category, familiarity, visual complexity, object agreement, viewpoint agreement, and manipulability. Stimuli are also available in grayscale, blurred, scrambled, and line-drawn version. This set of objects, the Bank Of Standardized Stimuli (BOSS), was created specifically to meet the needs of scientists in cognition, vision and psycholinguistics who work with photo stimuli

    Risperidone potentiates the sympathetic and hyperthermic reactions induced by orexin A in the rat.

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    This experiment tested the effect of risperidone on the sympathetic and thermogenic effects induced by orexin A. The firing rates of sympathetic nerves to interscapular brown adipose tissue (IBAT), along with IBAT and colon temperatures and heart rate were monitored in urethane-anesthetized male Sprague-Dawley rats before an injection of orexin A (1.5 nmol) into the lateral cerebral ventricle and over a period of 2 hours after the injection. The same variables were monitored in rats with an intraperitoneal administration of risperidone (50 mg/kg bw), injected 30 min before the orexin administration. The results show that orexin A increases the sympathetic firing rate, IBAT, colonic temperatures and heart rate. This increase is enhanced by the injection of risperidone. These findings suggest that risperidone elevates the responses due to orexin, probably through an involvement of serotoninergic and dopaminergic pathways, which are affected by risperidone. Furthermore, we suggested the name "hyperthermine A" as additional denomination of "orexin A" by considering the strong influence of this neuropeptide on body temperature

    Extracellular GABA in the medial hypothalamus is increased following hypocretin-1 administration.

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    Hypocretin 1 is an hypothalamic neuropeptide that induces an increase in food intake when administered into the cerebral lateral ventricle. As it is well known that the medial hypothalamus (MH) is involved in the feeding behaviour also through GABAergic circuits, the aim of this experiment was to investigate the effect of an hypocretin 1 intracerebroventricular (icv) injection on the extracellular levels of GABA in the MH.GABA levels in the MH were evaluated in six rats by microdialysis and high performance liquid chromatography-electrochemical detection 30 min before and every 30 min for an over all period of 6 h after an icv injection of hypocretin 1. The same procedure was used in another group of six rats but saline was injected into the lateral ventricle as control.The results show that extracellular GABA increases in the MH after the injection of hypocretin 1 at 60 min and at 3 h after the injection.This finding suggests a possible mechanism by which hypocretin 1 should induce hyperphagia in the first hour after injection. As it is already known that the inhibition of the MH by injection of GABA causes an increase of food intake, it is possible that hypocretin 1 causes an increase in food intake by increasing the GABA release in the MH. The lack of an increase in the GABA level after the fourth hour is consistent with the lack of an increase in food intake at this time, as we observed in previous experiments. The finding of a biphasic increase in the GABA level, at 60 min and at 3 h, was unexpected and should be further investigated
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