478 research outputs found

    The past and future roles of competition and habitat in the range-wide occupancy dynamics of Northern Spotted Owls

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    Slow ecological processes challenge conservation. Short-term variability can obscure the importance of slower processes that may ultimately determine the state of a system. Furthermore, management actions with slow responses can be hard to justify. One response to slow processes is to explicitly concentrate analysis on state dynamics. Here, we focus on identifying drivers of Northern Spotted Owl (Strix occidentalis caurina) territorial occupancy dynamics across 11 study areas spanning their geographic range and forecasting response to potential management actions. Competition with Barred Owls (Strix varia) has increased Spotted Owl territory extinction probabilities across all study areas and driven recent declines in Spotted Owl populations. Without management intervention, the Northern Spotted Owl subspecies will be extirpated from parts of its current range within decades. In the short term, Barred Owl removal can be effective. Over longer time spans, however, maintaining or improving habitat conditions can help promote the persistence of northern spotted owl populations. In most study areas, habitat effects on expected Northern Spotted Owl territorial occupancy are actually greater than the effects of competition from Barred Owls. This study suggests how intensive management actions (removal of a competitor) with rapid results can complement a slower management action (i.e., promoting forest succession)

    Hematology and serum biochemistry values of free-ranging Iberian wolves (Canis lupus) trapped by leg-hold snares

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    Hematology and serum biochemistry are important tools in assessing the health and physiological status of wildlife populations. Nevertheless, studies on free-ranging wolves (Canis lupus) are scarce, and no reference values are available neither for Iberian wolves nor for wolves captured with leghold snares. We report 37 hematology and serum biochemistry variables obtained from 26 free-ranging Iberian wolves captured with leg-hold snares between 2007 and 2014, including variables previously not reported in the literature. The values obtained are similar to the published reference intervals for Scandinavian wolves captured by darting from a helicopter, except for higher values for mean corpuscular hemoglobin concentration (MCHC), red blood cell distribution width (RDW), leukocyte count, creatinine kinase (CK), ?-globulins, and total bilirubin (TBIL) and lower values for alkaline phosphatase (ALP). We propose that differences in leukocyte count, CK, and TBIL are related to the method of capture, while differences in RDW, MCHC, ALP, and ?-globulins could reflect physiological adaptations to environmental conditions, sampling, or pre-analytical artifacts. Lymphocyte count was lower and neutrophil/lymphocyte ratio was significantly higher in older, reproductive females, while ALP and phosphorus were higher in juvenile wolves. For the first time, we describe hematology and serum biochemistry values of free-ranging Iberian wolves captured with leg-hold snares. The data reported here is the first published reference for wolves captured with similar methods and for monitoring Iberian wolves populations’ physiological and health status.We thank Nuria Fandos and Carla Ferreira, rangers from Xunta de Galicia and Parque Nacional de los Picos de Europa, and volunteers who helped during the trapping sessions. The wolves were captured under projects financed by Associacao de Conservacao do Habitat do Lobo Iberico (ACHLI) in Portugal and by Picos de Europa National Park, Ministerio de Agricultura, Alimentacion y Medio Ambiente, and Xunta de Galicia in Spain. Sara Roque benefited from grant SFRH/BD/12291/2003 from Fundacao para a Ciencia e a Tecnologia. Jose V. Lopez-Bao was supported by a postdoctoral contract from the Spanish Ministry of Economy and Competitiveness. This is the paper no. 5 from the Iberian Wolf Research Team

    Synthesis and characterization of the tetranuclear iron(III) complex of a new asymmetric multidentate ligand. A structural model for purple acid phosphatases

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    The ligand, 2-((2-hydroxy-5-methyl-3-((pyridin-2-ylmethylamino)methyl)benzyl)(2-hydroxybenzyl)amino)acetic acid (H(3)HPBA), which contains a donor atom set that mimics that of the active site of purple acid phosphatase is described. Reaction of H(3)HPBA with iron(III) or iron(II) salts results in formation of the tetranuclear complex, [Fe-4(HPBA)(2)(OAc)(2)(mu-O)(mu-OH)(OH2)(2)]ClO4 center dot 5H(2)O. X-Ray structural analysis reveals the cation consists of four iron(III) ions, two HPBA(3-) ligands, two bridging acetate ligands, a bridging oxide ion and a bridging hydroxide ion. Each binucleating HPBA(3-) ligand coordinates two structurally distinct hexacoordinate iron(III) ions. The two metal ions coordinated to a HPBA(3-) ligand are linked to the two iron(III) metal ions of a second, similar binuclear unit by intramolecular oxide and hydroxide bridging moieties to form a tetramer. The complex has been further characterised by elemental analysis, mass spectrometry, UV-vis and MCD spectroscopy, X- ray crystallography, magnetic susceptibility measurements and variable-temperature Mossbauer spectroscopy

    Na+,K+-pump stimulation improves contractility in isolated muscles of mice with hyperkalemic periodic paralysis

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    In patients with hyperkalemic periodic paralysis (HyperKPP), attacks of muscle weakness or paralysis are triggered by K+ ingestion or rest after exercise. Force can be restored by muscle work or treatment with β2-adrenoceptor agonists. A missense substitution corresponding to a mutation in the skeletal muscle voltage-gated Na+ channel (Nav1.4, Met1592Val) causing human HyperKPP was targeted into the mouse SCN4A gene (mutants). In soleus muscles prepared from these mutant mice, twitch, tetanic force, and endurance were markedly reduced compared with soleus from wild type (WT), reflecting impaired excitability. In mutant soleus, contractility was considerably more sensitive than WT soleus to inhibition by elevated [K+]o. In resting mutant soleus, tetrodotoxin (TTX)-suppressible 22Na uptake and [Na+]i were increased by 470 and 58%, respectively, and membrane potential was depolarized (by 16 mV, P < 0.0001) and repolarized by TTX. Na+,K+ pump–mediated 86Rb uptake was 83% larger than in WT. Salbutamol stimulated 86Rb uptake and reduced [Na+]i both in mutant and WT soleus. Stimulating Na+,K+ pumps with salbutamol restored force in mutant soleus and extensor digitorum longus (EDL). Increasing [Na+]i with monensin also restored force in soleus. In soleus, EDL, and tibialis anterior muscles of mutant mice, the content of Na+,K+ pumps was 28, 62, and 33% higher than in WT, respectively, possibly reflecting the stimulating effect of elevated [Na+]i on the synthesis of Na+,K+ pumps. The results confirm that the functional disorders of skeletal muscles in HyperKPP are secondary to increased Na+ influx and show that contractility can be restored by acute stimulation of the Na+,K+ pumps. Calcitonin gene-related peptide (CGRP) restored force in mutant soleus but caused no detectable increase in 86Rb uptake. Repeated excitation and capsaicin also restored contractility, possibly because of the release of endogenous CGRP from nerve endings in the isolated muscles. These observations may explain how mild exercise helps locally to prevent severe weakness during an attack of HyperKPP

    A bacterial genome in transition - an exceptional enrichment of IS elements but lack of evidence for recent transposition in the symbiont Amoebophilus asiaticus

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    <p>Abstract</p> <p>Background</p> <p>Insertion sequence (IS) elements are important mediators of genome plasticity and are widespread among bacterial and archaeal genomes. The 1.88 Mbp genome of the obligate intracellular amoeba symbiont <it>Amoebophilus asiaticus </it>contains an unusually large number of transposase genes (n = 354; 23% of all genes).</p> <p>Results</p> <p>The transposase genes in the <it>A. asiaticus </it>genome can be assigned to 16 different IS elements termed ISCaa1 to ISCaa16, which are represented by 2 to 24 full-length copies, respectively. Despite this high IS element load, the <it>A. asiaticus </it>genome displays a GC skew pattern typical for most bacterial genomes, indicating that no major rearrangements have occurred recently. Additionally, the high sequence divergence of some IS elements, the high number of truncated IS element copies (n = 143), as well as the absence of direct repeats in most IS elements suggest that the IS elements of <it>A. asiaticus </it>are transpositionally inactive. Although we could show transcription of 13 IS elements, we did not find experimental evidence for transpositional activity, corroborating our results from sequence analyses. However, we detected contiguous transcripts between IS elements and their downstream genes at nine loci in the <it>A. asiaticus </it>genome, indicating that some IS elements influence the transcription of downstream genes, some of which might be important for host cell interaction.</p> <p>Conclusions</p> <p>Taken together, the IS elements in the <it>A. asiaticus </it>genome are currently in the process of degradation and largely represent reflections of the evolutionary past of <it>A. asiaticus </it>in which its genome was shaped by their activity.</p

    Mode of Effective Connectivity within a Putative Neural Network Differentiates Moral Cognitions Related to Care and Justice Ethics

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    BACKGROUND: Moral sensitivity refers to the interpretive awareness of moral conflict and can be justice or care oriented. Justice ethics is associated primarily with human rights and the application of moral rules, whereas care ethics is related to human needs and a situational approach involving social emotions. Among the core brain regions involved in moral issue processing are: medial prefrontal cortex, anterior (ACC) and posterior (PCC) cingulate cortex, posterior superior temporal sulcus (pSTS), insula and amygdala. This study sought to inform the long standing debate of whether care and justice moral ethics represent one or two different forms of cognition. METHODOLOGY/PRINCIPAL FINDINGS: Model-free and model-based connectivity analysis were used to identify functional neural networks underlying care and justice ethics for a moral sensitivity task. In addition to modest differences in patterns of associated neural activity, distinct modes of functional and effective connectivity were observed for moral sensitivity for care and justice issues that were modulated by individual variation in moral ability. CONCLUSIONS/SIGNIFICANCE: These results support a neurobiological differentiation between care and justice ethics and suggest that human moral behavior reflects the outcome of integrating opposing rule-based, self-other perspectives, and emotional responses

    The type 2C phosphatase Wip1: An oncogenic regulator of tumor suppressor and DNA damage response pathways

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    The Wild-type p53-induced phosphatase 1, Wip1 (or PPM1D), is unusual in that it is a serine/threonine phosphatase with oncogenic activity. A member of the type 2C phosphatases (PP2Cδ), Wip1 has been shown to be amplified and overexpressed in multiple human cancer types, including breast and ovarian carcinomas. In rodent primary fibroblast transformation assays, Wip1 cooperates with known oncogenes to induce transformed foci. The recent identification of target proteins that are dephosphorylated by Wip1 has provided mechanistic insights into its oncogenic functions. Wip1 acts as a homeostatic regulator of the DNA damage response by dephosphorylating proteins that are substrates of both ATM and ATR, important DNA damage sensor kinases. Wip1 also suppresses the activity of multiple tumor suppressors, including p53, ATM, p16INK4a and ARF. We present evidence that the suppression of p53, p38 MAP kinase, and ATM/ATR signaling pathways by Wip1 are important components of its oncogenicity when it is amplified and overexpressed in human cancers

    Long telomeres are associated with clonality in wild populations of the fissiparous starfish Coscinasterias tenuispina

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    7 páginas, 4 figuras, 3 tablasTelomeres usually shorten during an organism’s lifespan and have thus been used as an aging and health marker. When telomeres become sufficiently short, senescence is induced. The most common method of restoring telomere length is via telomerase reverse transcriptase activity, highly expressed during embryogenesis. However, although asexual reproduction from adult tissues has an important role in the life cycles of certain species, its effect on the aging and fitness of wild populations, as well as its implications for the long-term survival of populations with limited genetic variation, is largely unknown. Here we compare relative telomere length of 58 individuals from four populations of the asexually reproducing starfish Coscinasterias tenuispina. Additionally, 12 individuals were used to compare telomere lengths in regenerating and non-regenerating arms, in two different tissues (tube feet and pyloric cecum). The level of clonality was assessed by genotyping the populations based on 12 specific microsatellite loci and relative telomere length was measured via quantitative PCR. The results revealed significantly longer telomeres in Mediterranean populations than Atlantic ones as demonstrated by the Kruskal–Wallis test (K=24.17, significant value: P-valueo0.001), with the former also characterized by higher levels of clonality derived from asexual reproduction. Telomeres were furthermore significantly longer in regenerating arms than in non-regenerating arms within individuals (pyloric cecum tissue: Mann–Whitney test, V=299, P-valueo10− 6; and tube feet tissue Student's t= 2.28, P-value =0.029). Our study suggests that one of the mechanisms responsible for the long-term somatic maintenance and persistence of clonal populations is telomere elongation.This research was financially supported by a PhD fellowship FPI-MICINN (BES-2011-044154) (ACG), the European ASSEMBLY project (227799), the Swedish Royal Academy of Sciences (ACG) and the Spanish Government project CTM2010-22218-C02. The research was also supported by a ‘Juan de la Cierva’ contract from the Spanish Government (RPP) and by the Adlerbertska Research Foundation (HNS).Peer reviewe
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