bluuebunny/crossref_metadata_2025_split huggingface dataset:
Infusion of brain‐derived neurotrophic factor into the ventral tegmental area switches the substrates mediating ethanol motivation
Authors: Ting‐A‐Kee Ryan , Vargas‐Perez Hector , Bufalino Mary‐Rose , Bahi Amine , Dreyer Jean‐Luc , Tyndale Rachel F. , van der Kooy Derek 
Published: December 2012

AbstractRecent work has shown that infusion of brain‐derived neurotrophic factor (BDNF) into the ventral tegmental area (VTA) promotes a switch in the mechanisms mediating morphine motivation, from a dopamine‐independent to a dopamine‐dependent pathway. Here we showed that a single infusion of intra‐VTA BDNF also promoted a switch in the mechanisms mediating ethanol motivation, from a dopamine‐dependent to a dopamine‐independent pathway (exactly opposite to that seen with morphine). We suggest that intra‐VTA BDNF, via its actions on TrkB receptors, precipitates a switch similar to that which occurs naturally when mice transit from a drug‐naive, non‐deprived state to a drug‐deprived state. The opposite switching of the mechanisms underlying morphine and ethanol motivation by BDNF in previously non‐deprived animals is consistent with their proposed actions on VTA GABAA receptors.
Home ranges of introduced rats on Christmas Island: A pilot study
Authors: Low Bing W. , Mills Harriet , Algar David , Hamilton Neil 
Published: December 2012

SummaryUnderstanding the spatial ecology of invasive rats (Rattus spp.) is necessary to inform management actions to reduce their impact on native flora and fauna. This study investigates home range sizes of exotic rats around seabird colonies and urban areas on Christmas Island, where rat predation is suspected to be adversely affecting fledgling success among local seabirds. It was hypothesised that rat home range sizes would be smaller in urban areas owing to more consistent food availability. Home ranges of male rats were significantly larger compared with their female counterparts, with male rats maintaining larger home ranges in urban areas compared with seabird colonies. Conversely, female rats had smaller home ranges in urban areas compared with seabird colonies. Our findings suggest a possible correlation between the spatial distribution of food resources and home range size. Additionally, the spatial distribution of breeding females across the landscape had a significant influence on the home ranges of male rats. These findings have important implications for proposed efforts to manage rat populations on Christmas Island, while also providing valuable information regarding the ecology of invasive rats on tropical islands.
Constitutionalising EU Executive Rule‐Making Procedures: A Research Agenda
Authors: Curtin Deirdre , Hofmann Herwig , Mendes Joana 
Published: December 2012

AbstractThe existence or non‐existence of procedural rules for executive rule‐making in the EU is not merely a ‘technical’ question free of constitutional value choices. This article argues that constitutional principles, such as transparency, openness and participatory democracy, highlighted by the Treaty of Lisbon constitute decisive normative standards for the design of administrative procedures in the EU, with a considerable impact on substantive outcomes. We apply such principles to executive rule‐making procedures in the EU, highlight the salience of this discussion and argue that systematisation of executive rule‐making procedures is needed in order to implement constitutional principles in a complex and plural environment.
Antibodies to OspC, OspF and C6 antigens as indicators for infection with Borrelia burgdorferi in horses
Authors: Wagner B. , Goodman L. B. , Rollins A. , Freer H. S. 
Published: December 2012

SummaryReasons for performing studyLyme disease is caused by Borrelia burgdorferi, which is transmitted by infected ticks (Ixodes spp.). Reports on Lyme disease in horses have increased in recent years. Nevertheless, the diagnosis of Lyme disease in horses is still challenging owing to its vague clinical presentation and the limitations of diagnostic tests.ObjectivesThis study used a new serological Lyme multiplex assay to examine antibody responses to 3 antigens of B. burgdorferi, outer surface protein (Osp) C, OspF and C6, and to verify their use as markers for early and late infection stages in horses.MethodsMultiplex analysis of antibodies to OspC, OspF and C6 in equine patient sera (n = 191) was performed. A subset of the sera (n = 90) was also tested using a commercial C6‐based Lyme test.ResultsAntibodies to OspF and C6 highly correlate as reliable markers of infection with B. burgdorferi in horses. Antibodies to OspC, which have been confirmed as early infection markers in man and dogs, were only detected in some patient sera, suggesting that OspC antibodies are indicators of early infection in horses. Commercial C6 testing identified most infected horses but also resulted in false positive and false negative interpretations.ConclusionsSerological multiplex testing is a rapid and quantitative diagnostic method to confirm infection with B. burgdorferi and to identify the stage of infection. In horses with risk of exposure and clinical signs, multiplex testing supports the diagnosis of Lyme disease.Potential relevanceAntimicrobial treatment of B. burgdorferi is time sensitive. Treatment success decreases with time of persistent infection, while the risk of developing chronic disease increases. The ability to identify early infection with B. burgdorferi provides practitioners and clinicians with a tool to improve the diagnosis of equine Lyme disease and make treatment decisions.
Serum amyloidAconcentration in healthy periparturient mares and mares with ascending placentitis
Authors: Coutinho da Silva M. A. , Canisso I. F. , MacPherson M. L. , Johnson A. E. M. , Divers T. J. 
Published: December 2012

SummaryReasons for performing studyPlacentitis is a prevalent cause of abortion, premature delivery and neonatal death in mares. Early diagnosis is paramount for the survival of the fetus and delivery of a live foal.ObjectivesTo determine: 1) Serum amyloidA(SAA) profile in healthy mares during late gestation; 2) if placentitis affectsSAAconcentrations and 3) the effects of therapy onSAAconcentrations and pregnancy outcome in mares with placentitis.MethodsIn ExperimentI, 15 healthy pregnant mares were evaluated from 280 days of gestation to 60 hpost partum. In ExperimentII, pregnant mares were inoculated intra‐cervically withStreptococcus zooepidemicus(Day 280–295) and assigned to control (n = 5) and treatment (n = 9) groups. Treatment was initiated at the onset of clinical signs. Serum amyloidAconcentrations were determined prior to inoculation and then weekly until abortion or delivery.ResultsSerum amyloidAremained at low concentrations (95% confidence interval [CI]: 3.2–8.1 mg/l) during late gestation followed by a significant increase within 36 hpost partum;SAAreturned to basal concentrations by 60 hpost partum. In ExperimentII,SAAsignificantly increased within 96 ± 56 h of inoculation in control mares followed by abortion. Therapy was effective (P<0.05) in preventing the rise inSAAin 66% (6/9) of mares and only one out of 3 mares with increasedSAAaborted. Overall, the incidence of abortion was higher in mares with increasedSAAconcentrations (75%; 6/8) compared with mares in whichSAAremained at baseline concentrations (0/6).ConclusionsMares with placentitis had significant increasedSAAwithin 96 h post inoculation and concentrations remained increased until abortion in untreated mares. Successful treatment either prevented the rise ofSAAconcentration or decreased its concentration to baseline concentrations, followed by delivery of a live foal.Potential relevanceSerum amyloidAmay be used as a prognostic indicator in cases of ascending placentitis in the mare.
Occurrence of glycerol uptake in Dunaliella tertiolecta under hyperosmotic stress
Authors: Lin Huixin , Fang Lei , Low Chin Seng , Chow Yvonne , Lee Yuan Kun 
Published: December 2012

The unicellular halotolerant green alga species Dunaliella are able to proliferate in extremely varied salinities by synthesizing intracellular glycerol and adjusting the cell shape and volume. However, some marine Dunaliella species such as Dunaliella tertiolecta are not able to regulate cell volume as an immediate response to counter external osmotic shock. Here we report that a rapid shock‐response mechanism is present in Dunaliella tertiolecta, involving uptake of exogenous glycerol in response to hyperosmotic shock without changing cell volume, and this glycerol uptake activity is associated with the Dunaliella tertiolecta glycerol uptake protein 1 (DtGUP1) gene, which belongs to the membrane‐bound O‐acyltransferase. The mutant DtGUP1‐E, in which the DtGUP1 gene is silenced, displayed an inability to take up glycerol from the medium and showed cell death under hyperosmotic shock. To our knowledge, this is the first time a gene product has been reported in Dunaliella tertiolecta that is involved in glycerol uptake activity under hyperosmotic stress.
Parthenogenetic populations of the freshwater snailCampeloma limumoccupy habitats with fewer environmental stressors than their sexual counterparts
Authors: CRUMMETT LISA T. , SEARS BRITTANY F. , LAFON DAVID C. , WAYNE MARTA L. 
Published: December 2012

Summary1. Sexual organisms should have half the reproductive rate of their parthenogenetic counterparts (i.e. twofold cost of sex), so the plethora of sexual species relative to parthenogenetic species remains an evolutionary paradox. The rarity of parthenogenesis may in part be due to the accumulation of deleterious mutations. Indeed, parthenogenetic populations of the freshwater snailCampeloma limumhave a greater mutation load relative to sexual populations ofC. limum, although this does not directly affect their reproductive fitness. We hypothesise that although parthenogenesis has no direct effect on fitness inC. limum, mutation accumulation and environmental stress act synergistically to limit the distribution of parthenogenetic populations.2. We evaluated this hypothesis, predicting that parthenogenetic populations ofC. limumwould inhabit sites with fewer environmental stressors than their sexual counterparts. We collected water quality, population density and individual size data at multiple time points from eight parthenogenetic and five sexual populations in the south‐eastern United States (Georgia and South Carolina).3. Consistent with our hypothesis, sexual populations ofC. limuminhabited poorer‐quality areas (sites with significantly lower dissolved oxygen and significantly more faecal coliform bacteria) than parthenogenetic populations. Despite these stressors, sexual populations still exhibited significantly higher population density than parthenogenetic populations.4. Our findings support the hypothesis that mutation‐laden parthenogeneticC. limumpopulations occupy habitats with fewer environmental stressors relative to their sexual counterparts. Moreover, sexualC. limumpopulations inhabit lower‐quality habitats where they can presumably evade the twofold cost of sex in the absence of competition from their parthenogenetic counterparts.
Responses of microbial phototrophs to late‐Holocene environmental forcing of lakes in south‐west Greenland
Authors: REUSS NINA S. , ANDERSON N. JOHN , FRITZ SHERILYN C. , SIMPSON GAVIN L. 
Published: December 2012

Summary1. The biological structure of arctic lakes is changing rapidly, apparently in response to global change processes such as increasing air temperatures, although altered nutrient stoichiometry may also be an important driver. Equally important, however, are local factors (e.g. landscape setting, hydrological linkages and trophic interactions) that may mediate responses of individual lakes at the regional scale. Despite general acknowledgement of the importance of local factors, there has been little focus on among‐lake variability in the response to environmental change.2. Sedimentary pigments, organic carbon and nitrogen, and biogenic silica (BSi) in 210Pb and 14C‐dated sediment cores from three contrasting lakes in the Kangerlussuaq area (c. 67°N, 51°W) of south‐west Greenland were used to reconstruct algal and phototrophic bacterial ecological change during the late‐Holocene. Water chemistry for the individual lakes varies in terms of conductivity (range: 30–3000 μS cm−1) and stratification regimes (cold monomictic, dimictic and meromictic), linked with their position along the regional climate gradient from the coast and to the present ice sheet margin.3. Despite essentially similar regional climate forcing over the last c. 1000 years, marked differences among lake types were observed in the phototrophic communities and their temporal variability. Considerable short‐term variability occurred in an oligosaline, meromictic lake (SS1371), dominated by purple sulphur bacterial pigments, most likely due to a tight coupling between the position of the chemocline and the phototrophic community. Communities in a lake (SS86) located on a nunatak, just beyond the edge of the present ice sheet shifted in a nonlinear pattern, approximately 1000 cal. years BP, possibly due to lake‐level lowering and loss of outflow during the Medieval Climate Anomaly. This regime shift was marked by a substantial expansion of green sulphur bacteria.4. A dilute, freshwater coastal lake (SS49) dominated by benthic algae was relatively stable until ca. 1900 AD when rates of community change began to increase. These changes in benthic algal pigments are correlated with substantial declines (1.3–0.44‰) in δ15N that are indicative of increased deposition of atmospheric inputs of industrially derived NOx into the atmosphere.5. Climate control on lake ecosystem functioning has been assumed to be particularly important in the Arctic. This study, however, illustrates a complex spatial response to climate forcing at the regional scale and emphasises differences in the relative importance of changes in the mass (m, both precipitation and nutrients) and energy flux (E) to lakes for the phototrophic community structure of low‐arctic Greenland lakes.
Climate‐induced changes in the distribution of freshwater fish: observed and predicted trends
Authors: COMTE LISE , BUISSON LAËTITIA , DAUFRESNE MARTIN , GRENOUILLET GAËL 
Published: December 2012

Summary1. Climate change could be one of the main threats faced by aquatic ecosystems and freshwater biodiversity. Improved understanding, monitoring and forecasting of its effects are thus crucial for researchers, policy makers and biodiversity managers.2. Here, we provide a review and some meta‐analyses of the literature reporting both observed and predicted climate‐induced effects on the distribution of freshwater fish. After reviewing three decades of research, we summarise how methods in assessing the effects of climate change have evolved, and whether current knowledge is geographically or taxonomically biased. We conducted multispecies qualitative and quantitative analyses to find out whether the observed responses of freshwater fish to recent changes in climate are consistent with those predicted under future climate scenarios.3. We highlight the fact that, in recent years, freshwater fish distributions have already been affected by contemporary climate change in ways consistent with anticipated responses under future climate change scenarios: the range of most cold‐water species could be reduced or shift to higher altitude or latitude, whereas that of cool‐ and warm‐water species could expand or contract.4. Most evidence about the effects of climate change is underpinned by the large number of studies devoted to cold‐water fish species (mainly salmonids). Our knowledge is still incomplete, however, particularly due to taxonomic and geographic biases.5. Observed and expected responses are well correlated among families, suggesting that model predictions are supported by empirical evidence. The observed effects are of greater magnitude and show higher variability than the predicted effects, however, indicating that other drivers of changes may be interacting with climate and seriously affecting freshwater fish.6. Finally, we suggest avenues of research required to address current gaps in what we know about the climate‐induced effects on freshwater fish distribution, including (i) the need for more long‐term data analyses, (ii) the assessment of climate‐induced effects at higher levels of organisation (e.g. assemblages), (iii) methodological improvements (e.g. accounting for uncertainty among projections and species’ dispersal abilities, combining both distributional and empirical approaches and including multiple non‐climatic stressors) and (iv) systematic confrontation of observed versus predicted effects across multi‐species assemblages and at several levels of biological organisation (i.e. populations and assemblages).
Winter climate change and coastal wetland foundation species: salt marshes vs. mangrove forests in the southeastern United States
Authors: Osland Michael J. , Enwright Nicholas , Day Richard H. , Doyle Thomas W. 
Published: December 2012

AbstractWe live in an era of unprecedented ecological change in which ecologists and natural resource managers are increasingly challenged to anticipate and prepare for the ecological effects of future global change. In this study, we investigated the potential effect of winter climate change upon salt marsh and mangrove forest foundation species in the southeastern United States. Our research addresses the following three questions: (1) What is the relationship between winter climate and the presence and abundance of mangrove forests relative to salt marshes; (2) How vulnerable are salt marshes to winter climate change‐induced mangrove forest range expansion; and (3) What is the potential future distribution and relative abundance of mangrove forests under alternative winter climate change scenarios? We developed simple winter climate‐based models to predict mangrove forest distribution and relative abundance using observed winter temperature data (1970–2000) and mangrove forest and salt marsh habitat data. Our results identify winter climate thresholds for salt marsh–mangrove forest interactions and highlight coastal areas in the southeastern United States (e.g., Texas, Louisiana, and parts of Florida) where relatively small changes in the intensity and frequency of extreme winter events could cause relatively dramatic landscape‐scale ecosystem structural and functional change in the form of poleward mangrove forest migration and salt marsh displacement. The ecological implications of these marsh‐to‐mangrove forest conversions are poorly understood, but would likely include changes for associated fish and wildlife populations and for the supply of some ecosystem goods and services.
Gap filling strategies and error in estimating annual soil respiration
Authors: Gomez‐Casanovas Nuria , Anderson‐Teixeira Kristina , Zeri Marcelo , Bernacchi Carl J. , DeLucia Evan H. 
Published: December 2012

AbstractSoil respiration (Rsoil) is one of the largest CO2 fluxes in the global carbon (C) cycle. Estimation of annual Rsoil requires extrapolation of survey measurements or gap filling of automated records to produce a complete time series. Although many gap filling methodologies have been employed, there is no standardized procedure for producing defensible estimates of annual Rsoil. Here, we test the reliability of nine different gap filling techniques by inserting artificial gaps into 20 automated Rsoil records and comparing gap filling Rsoil estimates of each technique to measured values. We show that although the most commonly used techniques do not, on average, produce large systematic biases, gap filling accuracy may be significantly improved through application of the most reliable methods. All methods performed best at lower gap fractions and had relatively high, systematic errors for simulated survey measurements. Overall, the most accurate technique estimated Rsoil based on the soil temperature dependence of Rsoil by assuming constant temperature sensitivity and linearly interpolating reference respiration (Rsoil at 10 °C) across gaps. The linear interpolation method was the second best‐performing method. In contrast, estimating Rsoil based on a single annual Rsoil – Tsoil relationship, which is currently the most commonly used technique, was among the most poorly‐performing methods. Thus, our analysis demonstrates that gap filling accuracy may be improved substantially without sacrificing computational simplicity. Improved and standardized techniques for estimation of annual Rsoil will be valuable for understanding the role of Rsoil in the global C cycle.
Local temperatures inferred from plant communities suggest strong spatial buffering of climate warming across Northern Europe
Authors: Lenoir Jonathan , Graae Bente Jessen , Aarrestad Per Arild , Alsos Inger Greve , Armbruster W. Scott , Austrheim Gunnar , Bergendorff Claes , Birks H. John B. , Bråthen Kari Anne , Brunet Jörg , Bruun Hans Henrik , Dahlberg Carl Johan , Decocq Guillaume , Diekmann Martin , Dynesius Mats , Ejrnæs Rasmus , Grytnes John‐Arvid , Hylander Kristoffer , Klanderud Kari , Luoto Miska , Milbau Ann , Moora Mari , Nygaard Bettina , Odland Arvid , Ravolainen Virve Tuulia , Reinhardt Stefanie , Sandvik Sylvi Marlen , Schei Fride Høistad , Speed James David Mervyn , Tveraabak Liv Unn , Vandvik Vigdis , Velle Liv Guri , Virtanen Risto , Zobel Martin , Svenning Jens‐Christian 
Published: December 2012

AbstractRecent studies from mountainous areas of small spatial extent (<2500 km2) suggest that fine‐grained thermal variability over tens or hundreds of metres exceeds much of the climate warming expected for the coming decades. Such variability in temperature provides buffering to mitigate climate‐change impacts. Is this local spatial buffering restricted to topographically complex terrains? To answer this, we here study fine‐grained thermal variability across a 2500‐km wide latitudinal gradient in Northern Europe encompassing a large array of topographic complexities. We first combined plant community data, Ellenberg temperature indicator values, locally measured temperatures (LmT) and globally interpolated temperatures (GiT) in a modelling framework to infer biologically relevant temperature conditions from plant assemblages within <1000‐m2 units (community‐inferred temperatures: CiT). We then assessed: (1) CiT range (thermal variability) within 1‐km2 units; (2) the relationship between CiT range and topographically and geographically derived predictors at 1‐km resolution; and (3) whether spatial turnover in CiT is greater than spatial turnover in GiT within 100‐km2 units. Ellenberg temperature indicator values in combination with plant assemblages explained 46–72% of variation in LmT and 92–96% of variation in GiT during the growing season (June, July, August). Growing‐season CiT range within 1‐km2 units peaked at 60–65°N and increased with terrain roughness, averaging 1.97 °C (SD = 0.84 °C) and 2.68 °C (SD = 1.26 °C) within the flattest and roughest units respectively. Complex interactions between topography‐related variables and latitude explained 35% of variation in growing‐season CiT range when accounting for sampling effort and residual spatial autocorrelation. Spatial turnover in growing‐season CiT within 100‐km2 units was, on average, 1.8 times greater (0.32 °C km−1) than spatial turnover in growing‐season GiT (0.18 °C km−1). We conclude that thermal variability within 1‐km2 units strongly increases local spatial buffering of future climate warming across Northern Europe, even in the flattest terrains.