677 research outputs found

    Microturbelarios de la Península Ibérica

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    Seasonal Migration and Home Ranges of Female Elk in the Black Hills of South Dakota and Wyoming

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    Understanding the movement and dispersion patterns of elk (Cervus elaphus) on public lands and the underlying factors that affect each will facilitate elk management and help resolve conflicts between management that benefit elk and other uses of land resources. Consequently, there is a need to identify and examine the movement and dispersion patterns of elk in the Black Hills of South Dakota and Wyoming. Our study quantified seasonal movements, determined home ranges of female elk in two areas of the Black Hills, and examined underlying factors associated with each. Elk in the northern area did not demonstrate seasonal migration patterns. Rather, winter ranges in the northern area were contained mostly within the boundaries of the summer range. Elk in the southern area exhibited a north-south migration pattern that coincided with seasonal patterns of snowfall. These elk migrated to winter range in late November and returned to summer range in late April. Home ranges of elk in the southern area were larger (P \u3c 0.01) than home ranges in the northern area. Landscape characteristics with marginally-significant correlations to elk home range area included road density (P = 0.10), and forage:cover ratio (P = 0.08); density of primary and secondary roads and average slope were significantly correlated with elk home range area (P \u3c 0.01). Managers can use this information to develop strategies that meet population goals and reduce conflicts between management for elk and with other resources

    Nuevas aportaciones al conocimiento de los microturbelarios de la Península Ibérica

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    In this study, seven species of freshwater Microturbellaria are recorded for the first time from the Iberian fauna, belonging to the Orders: Macrostomida (Macrostomum rostratum), Proseriata (Bothrioplana semperi) and Rhabdocoela (Castradella gladiata, Opistomum inmigrans, Phaenocora minima, Microdalyellia kupelweiseri and M. tenennsensis). Other five species are recorded for the second time: Prorhynchus stagnalis (O. Lecithoepitheliata), Opisthocystis goettei, Castrella truncata, Mesostoma ehrenbergii and Rhynchomesostoma rostratum (O. Rhabdocoela). The specimens were collected from eight localities in the provinces of Avila, Cuenca, Guadalajara, Madrid and Segovia. In this report, we bring new data about ecology and distribution of all these species.En el presente trabajo se citan por vez primera para la fauna ibérica siete especies de Microturbelarios pertenecientes a los Órdenes: Macrostomida (Macrostomum rostratum), Proseriata (Bothrioplana semperi) y Rhabdocoela (Castradella gladiata, Opistomum inmigrans, Phaenocora minima, Microdalyellia kupelweiseri y M. tenennsensis). Otras cinco especies se citan por segunda vez: Prorhynchus stagnalis (O. Lecithoepitheliata), Opisthocystis goettei, Castrella truncata, Mesostoma ehrenbergii y Rhynchomesostoma rostratum (O. Rhabdocoela). El material estudiado fue recogido en ocho localidades de las provincias de Avila, Cuenca, Guadalajara, Madrid y Segovia, ofreciéndose nuevos datos sobre la autoecología y distribución de estas especies

    Limits to sustained energy intake XXIV : impact of suckling behaviour on the body temperatures of lactating female mice

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    We would like to thank the animal house staff and all members of the Energetics group for their invaluable help at various stages throughout the project. This work was supported by Natural Environment Research Council grant (NERC, NE/C004159/1). YG was supported by a scholarship from the rotary foundation. LV was supported by a Rubicon grant from the Netherlands Scientific Organisation (NWO).Peer reviewedPublisher PD

    Machine learning-based phenotypic imaging to characterise the targetable biology of <i>Plasmodium falciparum</i> male gametocytes for the development of transmission-blocking antimalarials

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    Preventing parasite transmission from humans to mosquitoes is recognised to be critical for achieving elimination and eradication of malaria. Consequently developing new antimalarial drugs with transmission-blocking properties is a priority. Large screening campaigns have identified many new transmission-blocking molecules, however little is known about how they target the mosquito-transmissible Plasmodium falciparum stage V gametocytes, or how they affect their underlying cell biology. To respond to this knowledge gap, we have developed a machine learning image analysis pipeline to characterise and compare the cellular phenotypes generated by transmission-blocking molecules during male gametogenesis. Using this approach, we studied 40 molecules, categorising their activity based upon timing of action and visual effects on the organisation of tubulin and DNA within the cell. Our data both proposes new modes of action and corroborates existing modes of action of identified transmission-blocking molecules. Furthermore, the characterised molecules provide a new armoury of tool compounds to probe gametocyte cell biology and the generated imaging dataset provides a new reference for researchers to correlate molecular target or gene deletion to specific cellular phenotype. Our analysis pipeline is not optimised for a specific organism and could be applied to any fluorescence microscopy dataset containing cells delineated by bounding boxes, and so is potentially extendible to any disease model

    NMDA Receptors Subserve Persistent Neuronal Firing during Working Memory in Dorsolateral Prefrontal Cortex

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    SummaryNeurons in the primate dorsolateral prefrontal cortex (dlPFC) generate persistent firing in the absence of sensory stimulation, the foundation of mental representation. Persistent firing arises from recurrent excitation within a network of pyramidal Delay cells. Here, we examined glutamate receptor influences underlying persistent firing in primate dlPFC during a spatial working memory task. Computational models predicted dependence on NMDA receptor (NMDAR) NR2B stimulation, and Delay cell persistent firing was abolished by local NR2B NMDAR blockade or by systemic ketamine administration. AMPA receptors (AMPARs) contributed background depolarization to sustain network firing. In contrast, many Response cells were sensitive to AMPAR blockade and increased firing after systemic ketamine, indicating that models of ketamine actions should be refined to reflect neuronal heterogeneity. The reliance of Delay cells on NMDAR may explain why insults to NMDARs in schizophrenia or Alzheimer’s disease profoundly impair cognition

    Drug Screen Targeted at Plasmodium Liver Stages Identifies a Potent Multistage Antimalarial Drug

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    Plasmodium parasites undergo a clinically silent and obligatory developmental phase in the host’s liver cells before they are able to infect erythrocytes and cause malaria symptoms. To overcome the scarcity of compounds targeting the liver stage of malaria, we screened a library of 1037 existing drugs for their ability to inhibit Plasmodium hepatic development. Decoquinate emerged as the strongest inhibitor of Plasmodium liver stages, both in vitro and in vivo. Furthermore, decoquinate kills the parasite’s replicative blood stages and is active against developing gametocytes, the forms responsible for transmission. The drug acts by selectively and specifically inhibiting the parasite’s mitochondrial bc1bc_1 complex, with little cross-resistance with the antimalarial drug atovaquone. Oral administration of a single dose of decoquinate effectively prevents the appearance of disease, warranting its exploitation as a potent antimalarial compound

    Drug Screen Targeted at Plasmodium Liver Stages Identifies a Potent Multistage Antimalarial Drug

    Get PDF
    Plasmodium parasites undergo a clinically silent and obligatory developmental phase in the host's liver cells before they are able to infect erythrocytes and cause malaria symptoms. To overcome the scarcity of compounds targeting the liver stage of malaria, we screened a library of 1037 existing drugs for their ability to inhibit Plasmodium hepatic development. Decoquinate emerged as the strongest inhibitor of Plasmodium liver stages, both in vitro and in vivo. Furthermore, decoquinate kills the parasite's replicative blood stages and is active against developing gametocytes, the forms responsible for transmission. The drug acts by selectively and specifically inhibiting the parasite's mitochondrial bc1 complex, with little cross-resistance with the antimalarial drug atovaquone. Oral administration of a single dose of decoquinate effectively prevents the appearance of disease, warranting its exploitation as a potent antimalarial compoun
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