310 research outputs found

    Bigger is fitter? Quantitative genetic decomposition of selection reveals an adaptive evolutionary decline of body mass in a wild rodent population

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    This is the final version of the article. Available from the publisher via the DOI in this record.In natural populations, quantitative trait dynamics often do not appear to follow evolutionary predictions. Despite abundant examples of natural selection acting on heritable traits, conclusive evidence for contemporary adaptive evolution remains rare for wild vertebrate populations, and phenotypic stasis seems to be the norm. This so-called "stasis paradox" highlights our inability to predict evolutionary change, which is especially concerning within the context of rapid anthropogenic environmental change. While the causes underlying the stasis paradox are hotly debated, comprehensive attempts aiming at a resolution are lacking. Here, we apply a quantitative genetic framework to individual-based long-term data for a wild rodent population and show that despite a positive association between body mass and fitness, there has been a genetic change towards lower body mass. The latter represents an adaptive response to viability selection favouring juveniles growing up to become relatively small adults, i.e., with a low potential adult mass, which presumably complete their development earlier. This selection is particularly strong towards the end of the snow-free season, and it has intensified in recent years, coinciding which a change in snowfall patterns. Importantly, neither the negative evolutionary change, nor the selective pressures that drive it, are apparent on the phenotypic level, where they are masked by phenotypic plasticity and a non causal (i.e., non genetic) positive association between body mass and fitness, respectively. Estimating selection at the genetic level enabled us to uncover adaptive evolution in action and to identify the corresponding phenotypic selective pressure. We thereby demonstrate that natural populations can show a rapid and adaptive evolutionary response to a novel selective pressure, and that explicitly (quantitative) genetic models are able to provide us with an understanding of the causes and consequences of selection that is superior to purely phenotypic estimates of selection and evolutionary change.The study was funded by a Swiss National Science Foundation (http://www.snf.ch) project grant (31003A_141110) awarded to EP

    Densities and phase equilibria of hydrogen, propane and vegetable oil mixtures. Experimental data and thermodynamic modeling

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    Heterogeneous catalytic gas-liquid reactions are intensified when carried out in the homogenous fluid phase by means of a supercritical co-solvent. For instance, supercritical propane is used to enhance yield in the hydrogenation of vegetable oils. Besides phase equilibrium knowledge, volumetric information is also needed to elucidate kinetic mechanisms and design continuous supercritical reactors. In this work, we report new experimental PvT data of the reactive mixture H2+sunflower oil+propane using the isochoric method. In addition, the phase equilibria and PvT data are modeled with the GCA and RK-PR equations of state, respectively. The isochoric method not only provides PvT information under the reaction conditions, but also the reactive system compressibility, key variable to attain enhanced transport properties in the supercritical reactors.Fil: Hegel, Pablo Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Cotabarren, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Brignole, Esteban Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Pereda, Selva. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. University of KwaZulu-Natal; Sudáfric

    Microsatellite primers for the four Galápagos mockingbird species (Mimus parvulus, Mimus macdonaldi, Mimus melanotis and Mimus trifasciatus)

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    Nineteen di- and tetranucleotide and one trinucleotide microsatellite DNA markers were isolated from the Galapagos mockingbird (Mimus parvulus) and tested for cross-species amplification in the other three mockingbird species in the Galapagos. In addition, primers for two microsatellite loci previously developed for Mimus polyglottos were redesigned to obtain shorter amplification fragments. The number of alleles per locus and species ranged from 1 to 8, and expected heterozygosity varied from 0.0 to 0.809. These microsatellite markers will be useful to study levels of inbreeding in different island populations

    Predictive Spatial Dynamics and Strategic Planning for Raccoon Rabies Emergence in Ohio

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    Rabies is an important public health concern in North America because of recent epidemics of a rabies virus variant associated with raccoons. The costs associated with surveillance, diagnostic testing, and post-exposure treatment of humans exposed to rabies have fostered coordinated efforts to control rabies spread by distributing an oral rabies vaccine to wild raccoons. Authorities have tried to contain westward expansion of the epidemic front of raccoon-associated rabies via a vaccine corridor established in counties of eastern Ohio, western Pennsylvania, and West Virginia. Although sporadic cases of rabies have been identified in Ohio since oral rabies vaccine distribution in 1998, the first evidence of a significant breach in this vaccine corridor was not detected until 2004 in Lake County, Ohio. Herein, we forecast the spatial spread of rabies in Ohio from this breach using a stochastic spatial model that was first developed for exploratory data analysis in Connecticut and next used to successfully hind-cast wave-front dynamics of rabies spread across New York. The projections, based on expansion from the Lake County breach, are strongly affected by the spread of rabies by rare, but unpredictable long-distance translocation of rabid raccoons; rabies may traverse central Ohio at a rate 2.5-fold greater than previously analyzed wildlife epidemics. Using prior estimates of the impact of local heterogeneities on wave-front propagation and of the time lag between surveillance-based detection of an initial rabies case to full-blown epidemic, specific regions within the state are identified for vaccine delivery and expanded surveillance effort

    Isolation of Lagos Bat Virus from Water Mongoose

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    One-sentence summary for table of contents: Lagos bat virus from water mongoose showed strong sequence homology with other Lagos bat virus isolates from South Africa

    Lagos Bat Virus, South Africa

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    Three more isolates of Lagos bat virus were recently recovered from fruit bats in South Africa after an apparent absence of this virus for 13 years. The sporadic occurrence of cases is likely due to inadequate surveillance programs for lyssavirus infections among bat populations in Africa

    Urban colonization through multiple genetic lenses: The city‐fox phenomenon revisited

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    Urbanization is driving environmental change on a global scale, creating novel environments for wildlife to colonize. Through a combination of stochastic and selective processes, urbanization is also driving evolutionary change. For instance, difficulty in traversing human‐modified landscapes may isolate newly established populations from rural sources, while novel selective pressures, such as altered disease risk, toxicant exposure, and light pollution, may further diverge populations through local adaptation. Assessing the evolutionary consequences of urban colonization and the processes underlying them is a principle aim of urban evolutionary ecology. In the present study, we revisited the genetic effects of urbanization on red foxes (Vulpes vulpes) that colonized Zurich, Switzerland. Through use of genome‐wide single nucleotide polymorphisms and microsatellite markers linked to the major histocompatibility complex (MHC), we expanded upon a previous neutral microsatellite study to assess population structure, characterize patterns of genetic diversity, and detect outliers associated with urbanization. Our results indicated the presence of one large evolutionary cluster, with substructure evident between geographic sampling areas. In urban foxes, we observed patterns of neutral and functional diversity consistent with founder events and reported increased differentiation between populations separated by natural and anthropogenic barriers. We additionally reported evidence of selection acting on MHC‐linked markers and identified outlier loci with putative gene functions related to energy metabolism, behavior, and immunity. We concluded that demographic processes primarily drove patterns of diversity, with outlier tests providing preliminary evidence of possible urban adaptation. This study contributes to our overall understanding of urban colonization ecology and emphasizes the value of combining datasets when examining evolutionary change in an increasingly urban world

    Renewed global partnerships and redesigned roadmaps for rabies prevention and control

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    Canine rabies, responsible for most human rabies deaths, is a serious global public health concern. This zoonosis is entirely preventable, but by focusing solely upon rabies prevention in humans, this "incurable wound" persists at high costs. Although preventing human deaths through canine rabies elimination is feasible, dog rabies control is often neglected, because dogs are not considered typical economic commodities by the animal health sector. Here, we demonstrate that the responsibility of managing rabies falls upon multiple sectors, that a truly integrated approach is the key to rabies elimination, and that considerable progress has been made to this effect. Achievements include the construction of global rabies networks and organizational partnerships; development of road maps, operational toolkits, and a blueprint for rabies prevention and control; and opportunities for scaling up and replication of successful programs. Progress must continue towards overcoming the remaining challenges preventing the ultimate goal of rabies elimination

    Factors Associated With Liver Steatosis in People With Human Immunodeficiency Virus on Contemporary Antiretroviral Therapy.

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    Background Given the impact of new antiretroviral drugs on weight and metabolic parameters, their potential contribution to the development of liver steatosis is of concern. We investigated the determinants of liver steatosis in patients on antiretroviral therapy (ART) in the Swiss HIV Cohort Study (SHCS). Methods Between 2019 and 2021, we measured liver stiffness and controlled attenuation parameter (CAP) using transient elastography in consecutive SHCS participants at Bern University Hospital. Individuals with viral hepatitis coinfection and pregnant women were excluded. We used multivariable logistic regression to explore factors associated with steatosis. Results Of 416 participants, 113 (27.2%) were female, median age was 51 years (interquartile range [IQR], 43-59), 305 (73.3%) were of European origin, and 212 (51.0%) were overweight/obese (body mass index [BMI] ≥25 kg/m2). Liver steatosis (CAP ≥248 dB/m) was present in 212 (51.0%) participants, 11 (5.2%) of whom had significant fibrosis or cirrhosis. One hundred seventy-nine (43.0%) met the criteria for metabolic-associated fatty liver disease (MAFLD). Among 64 individuals with a BMI <25 kg/m2 and liver steatosis, 31 (48.4%) had MAFLD. In multivariable analyses, BMI ≥25 kg/m2 (adjusted odds ratio, 5.76; 95% confidence interval, 3.57-9.29), age ≥50 years (1.88, 1.14-3.09), European origin (3.16, 1.69-5.89), and current use of tenofovir alafenamide (1.70, 1.08-2.69) were associated with liver steatosis. Exposure to integrase inhibitors was not associated with liver steatosis (0.83, 0.51-1.37). Conclusions Our findings suggest a high prevalence of liver steatosis among people with HIV (PWH) on ART in Switzerland. In addition to established risk factors, the use of tenofovir alafenamide was associated with hepatic steatosis

    Screening for Hepatocellular Carcinoma among adults with HIV/Hepatitis B coinfection in Zambia: A Pilot Study

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    Background & aims: Chronic hepatitis B virus (HBV) infection is the main cause of hepatocellular carcinoma (HCC) in sub-Saharan Africa (SSA). In an established cohort of HIV/HBV-coinfected individuals on antiretroviral therapy (ART), we piloted an HCC screening initiative at two outpatient clinics in Lusaka, Zambia. Methods: We performed abdominal ultrasound (AUS) and transient elastography in all patients. Results: Among 279 HIV/HBV-coinfected patients, 165 (59.1%) were men, median age was 34 years (interquartile range 28-39) and median CD4 count 246 cells/µl (112-355). While 102 (36.6%) individuals had elevated transaminases, 114 (40.9%) had HBV levels >2000 IU/mL and 59 (24.6%) significant fibrosis. On AUS, 75 (26.9%) participants had hepatomegaly and 69 (24.7%) peri-portal fibrosis. Five patients had a liver lesion >1cm, an indication for confirmatory imaging. Conclusions: In one of the first HCC screening initiatives in SSA, 2% of HIV/HBV-coinfected adults had significant liver lesions, and a quarter had findings suggestive of schistosomiasis-induced liver damage
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