563 research outputs found

    Designer receptors show role for ventral pallidum input to ventral tegmental area in cocaine seeking.

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    The ventral pallidum is centrally positioned within mesocorticolimbic reward circuits, and its dense projection to the ventral tegmental area (VTA) regulates neuronal activity there. However, the ventral pallidum is a heterogeneous structure, and how this complexity affects its role within wider reward circuits is unclear. We found that projections to VTA from the rostral ventral pallidum (RVP), but not the caudal ventral pallidum (CVP), were robustly Fos activated during cue-induced reinstatement of cocaine seeking--a rat model of relapse in addiction. Moreover, designer receptor-mediated transient inactivation of RVP neurons, their terminals in VTA or functional connectivity between RVP and VTA dopamine neurons blocked the ability of drug-associated cues (but not a cocaine prime) to reinstate cocaine seeking. In contrast, CVP neuronal inhibition blocked cocaine-primed, but not cue-induced, reinstatement. This double dissociation in ventral pallidum subregional roles in drug seeking is likely to be important for understanding the mesocorticolimbic circuits underlying reward seeking and addiction

    Identification and validation of a QTL influencing bitter pit symptoms in apple (Malus x domestica)

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    Bitter pit is one of the most economically important physiological disorders affecting apple fruit production, causing soft discrete pitting of the cortical flesh of the apple fruits which renders them unmarketable. The disorder is heritable; however, the environment and cultural practices play a major role in expression of symptoms. Bitter pit has been shown to be controllable to a certain extent using calcium sprays and dips; however, their use does not entirely prevent the incidence of the disorder. Previously, bitter pit has been shown to be controlled by two dominant genes, and markers on linkage group 16 of the apple genome were identified that were significantly associated with the expression of bitter pit symptoms in a genome-wide association study. In this investigation, we identified a major QTL for bitter pit defined by two microsatellite (SSR) markers. The association of the SSRs with the bitter pit locus, and their ability to predict severe symptom expression, was confirmed through screening of individuals with stable phenotypic expression from an additional mapping progeny. The data generated in this current study suggest a two gene model could account for the control of bitter pit symptom expression; however, only one of the loci was detectable, most likely due to dominance of alleles carried by both parents of the mapping progeny used. The SSR markers identified are cost-effective, robust and multi-allelic and thus should prove useful for the identification of seedlings with resistance to bitter pit using marker-assisted selection in apple breeding programs

    Revisiting the B-cell compartment in mouse and humans: more than one B-cell subset exists in the marginal zone and beyond.

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    International audienceABSTRACT: The immunological roles of B-cells are being revealed as increasingly complex by functions that are largely beyond their commitment to differentiate into plasma cells and produce antibodies, the key molecular protagonists of innate immunity, and also by their compartmentalisation, a more recently acknowledged property of this immune cell category. For decades, B-cells have been recognised by their expression of an immunoglobulin that serves the function of an antigen receptor, which mediates intracellular signalling assisted by companion molecules. As such, B-cells were considered simple in their functioning compared to the other major type of immune cell, the T-lymphocytes, which comprise conventional T-lymphocyte subsets with seminal roles in homeostasis and pathology, and non-conventional T-lymphocyte subsets for which increasing knowledge is accumulating. Since the discovery that the B-cell family included two distinct categories - the non-conventional, or extrafollicular, B1 cells, that have mainly been characterised in the mouse; and the conventional, or lymph node type, B2 cells - plus the detailed description of the main B-cell regulator, FcγRIIb, and the function of CD40+ antigen presenting cells as committed/memory B-cells, progress in B-cell physiology has been slower than in other areas of immunology. Cellular and molecular tools have enabled the revival of innate immunity by allowing almost all aspects of cellular immunology to be re-visited. As such, B-cells were found to express "Pathogen Recognition Receptors" such as TLRs, and use them in concert with B-cell signalling during innate and adaptive immunity. An era of B-cell phenotypic and functional analysis thus began that encompassed the study of B-cell microanatomy principally in the lymph nodes, spleen and mucosae. The novel discovery of the differential localisation of B-cells with distinct phenotypes and functions revealed the compartmentalisation of B-cells. This review thus aims to describe novel findings regarding the B-cell compartments found in the mouse as a model organism, and in human physiology and pathology. It must be emphasised that some differences are noticeable between the mouse and human systems, thus increasing the complexity of B-cell compartmentalisation. Special attention will be given to the (lymph node and spleen) marginal zones, which represent major crossroads for B-cell types and functions and a challenge for understanding better the role of B-cell specificities in innate and adaptive immunology

    Phenolic compounds in young developing kiwifruit in relation to light exposure: Implications for fruit calcium accumulation

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    The interaction between light availability and the biosynthesis of phenolic compounds in fruit of kiwifruit (Actinidia deliciosa var. deliciosa, C.F. Liang et A. R. Ferguson) was investigated. Fruits were exposed either to natural light or were artificially shaded while growing on mature vines and were analysed weekly during the first 11 weeks of development. Phenols were identified and quantified by using High Performance Liquid Chromatography (HPLC). Results showed that the predominant phenolic compounds were hydroxycinnamic acids (HCAs), flavonols and the flavan 3-ol epicatechin. Calcium (Ca2+), the main mineral nutrient involved in fruit quality was also determined. Light significantly increased the accumulation of both phenols and Ca2+ into the fruit. This work expands the list of known phenolics in kiwifruit and provides a possible explanation for the seasonal pattern of Ca2+ import into the fruit. Results on light–phenol interaction being apparently beneficial for fruit Ca2+ accumulation, suggest that accurate canopy management could enhance fruit quality

    Search for Dark Matter and Supersymmetry with a Compressed Mass Spectrum in the Vector Boson Fusion Topology in Proton-Proton Collisions at root s=8 TeV

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    Local and Global Effects of Climate on Dengue Transmission in Puerto Rico

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    The four dengue viruses, the agents of dengue fever and dengue hemorrhagic fever in humans, are transmitted predominantly by the mosquito Aedes aegypti. The abundance and the transmission potential of Ae. aegypti are influenced by temperature and precipitation. While there is strong biological evidence for these effects, empirical studies of the relationship between climate and dengue incidence in human populations are potentially confounded by seasonal covariation and spatial heterogeneity. Using 20 years of data and a statistical approach to control for seasonality, we show a positive and statistically significant association between monthly changes in temperature and precipitation and monthly changes in dengue transmission in Puerto Rico. We also found that the strength of this association varies spatially, that this variation is associated with differences in local climate, and that this relationship is consistent with laboratory studies of the impacts of these factors on vector survival and viral replication. These results suggest the importance of temperature and precipitation in the transmission of dengue viruses and suggest a reason for their spatial heterogeneity. Thus, while dengue transmission may have a general system, its manifestation on a local scale may differ from global expectations

    A Comprehensive DNA Barcode Library for the Looper Moths (Lepidoptera: Geometridae) of British Columbia, Canada

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    The construction of comprehensive reference libraries is essential to foster the development of DNA barcoding as a tool for monitoring biodiversity and detecting invasive species. The looper moths of British Columbia (BC), Canada present a challenging case for species discrimination via DNA barcoding due to their considerable diversity and limited taxonomic maturity.By analyzing specimens held in national and regional natural history collections, we assemble barcode records from representatives of 400 species from BC and surrounding provinces, territories and states. Sequence variation in the barcode region unambiguously discriminates over 93% of these 400 geometrid species. However, a final estimate of resolution success awaits detailed taxonomic analysis of 48 species where patterns of barcode variation suggest cases of cryptic species, unrecognized synonymy as well as young species.A catalog of these taxa meriting further taxonomic investigation is presented as well as the supplemental information needed to facilitate these investigations

    A Practical Guide to Rodent Islet Isolation and Assessment

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    Pancreatic islets of Langerhans secrete hormones that are vital to the regulation of blood glucose and are, therefore, a key focus of diabetes research. Purifying viable and functional islets from the pancreas for study is an intricate process. This review highlights the key elements involved with mouse and rat islet isolation, including choices of collagenase, the collagenase digestion process, purification of islets using a density gradient, and islet culture conditions. In addition, this paper reviews commonly used techniques for assessing islet viability and function, including visual assessment, fluorescent markers of cell death, glucose-stimulated insulin secretion, and intracellular calcium measurements. A detailed protocol is also included that describes a common method for rodent islet isolation that our laboratory uses to obtain viable and functional mouse islets for in vitro study of islet function, beta-cell physiology, and in vivo rodent islet transplantation. The purpose of this review is to serve as a resource and foundation for successfully procuring and purifying high-quality islets for research purposes

    Adaptive Contact Networks Change Effective Disease Infectiousness and Dynamics

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    Human societies are organized in complex webs that are constantly reshaped by a social dynamic which is influenced by the information individuals have about others. Similarly, epidemic spreading may be affected by local information that makes individuals aware of the health status of their social contacts, allowing them to avoid contact with those infected and to remain in touch with the healthy. Here we study disease dynamics in finite populations in which infection occurs along the links of a dynamical contact network whose reshaping may be biased based on each individual's health status. We adopt some of the most widely used epidemiological models, investigating the impact of the reshaping of the contact network on the disease dynamics. We derive analytical results in the limit where network reshaping occurs much faster than disease spreading and demonstrate numerically that this limit extends to a much wider range of time scales than one might anticipate. Specifically, we show that from a population-level description, disease propagation in a quickly adapting network can be formulated equivalently as disease spreading on a well-mixed population but with a rescaled infectiousness. We find that for all models studied here – SI, SIS and SIR – the effective infectiousness of a disease depends on the population size, the number of infected in the population, and the capacity of healthy individuals to sever contacts with the infected. Importantly, we indicate how the use of available information hinders disease progression, either by reducing the average time required to eradicate a disease (in case recovery is possible), or by increasing the average time needed for a disease to spread to the entire population (in case recovery or immunity is impossible)
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