57 research outputs found

    Evidence of energy and nutrient transfer from invasive pink salmon (Oncorhynchus gorbuscha) spawners to juvenile Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) in northern Norway

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    Recent large influxes of non-native Pacific pink salmon (Oncorhynchus gorbuscha) to North European rivers have raised concern over their potential negative impacts on native salmonids and recipient ecosystems. The eggs and carcasses of semelparous pink salmon may provide a significant nutrient and energy subsidy to native biota, but this phenomenon has not been widely documented outside the species' native distribution. We analysed the stomach contents and stable isotope values (δ15N and δ13C) in muscle and liver tissues of juvenile Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) to determine whether these native salmonids utilise marine-derived nutrients and energy provided by pink salmon eggs and carcasses in the subarctic river system Vesterelva, northern Norway. Although egg foraging and assimilation of marine-derived nutrients in fish body tissues were found to be minor at the population level, a few juvenile salmon and trout had recently eaten large quantities of pink salmon eggs. Some of these individuals also had high δ15N and δ13C values, indicating a long-term diet subsidised by marine-derived nutrients and energy from pink salmon eggs. Hence, our study provides novel evidence that the eggs of invasive pink salmon may provide an energetic, profitable food resource for juvenile native fish. More research is needed to understand the broader ecological implications for fishes and other biota in river ecosystems invaded by pink salmon. egg predation, marine-derived nutrients, non-native salmonids, resource subsidy, stable isotope analysis, subarctic riverpublishedVersio

    Rupture Pathway of Phosphatidylcholine Liposomes on Silicon Dioxide

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    We have investigated the pathway by which unilamellar POPC liposomes upon adsorption undergo rupture and form a supported lipid bilayer (SLB) on a SiO2 surface. Biotinylated lipids were selectively incorporated in the outer monolayer of POPC liposomes to create liposomes with asymmetric lipid compositions in the outer and inner leaflets. The specific binding of neutravidin and anti-biotin to SLBs formed by liposome fusion, prior to and after equilibrated flip-flop between the upper and lower monolayers in the SLB, were then investigated. It was concluded that the lipids in the outer monolayer of the vesicle predominantly end up on the SLB side facing the SiO2 substrate, as demonstrated by having maximum 30–40% of lipids in the liposome outer monolayer orienting towards the bulk after forming the SLB

    The Contribution of Religiosity to Ideology:Empirical Evidences From Five Continents

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    The current study examines the extent to which religiosity account for ideological orientations in 16 countries from five continents (Australia, Brazil, Chile, Germany, Greece, Finland, Israel, Italy, Japan, Poland, Slovakia, Spain, Turkey, Ukraine, the United Kingdom, and the United States). Results showed that religiosity was consistently related to right and conservative ideologies in all countries, except Australia. This relation held across different religions, and did not vary across participant’s demographic conditions (i.e., gender, age, income, and education). After controlling for basic personal values, the contribution of religiosity on ideology was still significant. However, the effect was substantial only in countries where religion has played a prominent role in the public sphere, such as Spain, Poland, Greece, Italy, Slovakia, and Turkey. In the other countries, the unique contribution of religiosity was marginal or small

    Structural Alterations in a Component of Cytochrome c Oxidase and Molecular Evolution of Pathogenic Neisseria in Humans

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    Three closely related bacterial species within the genus Neisseria are of importance to human disease and health. Neisseria meningitidis is a major cause of meningitis, while Neisseria gonorrhoeae is the agent of the sexually transmitted disease gonorrhea and Neisseria lactamica is a common, harmless commensal of children. Comparative genomics have yet to yield clear insights into which factors dictate the unique host-parasite relationships exhibited by each since, as a group, they display remarkable conservation at the levels of nucleotide sequence, gene content and synteny. Here, we discovered two rare alterations in the gene encoding the CcoP protein component of cytochrome cbb3 oxidase that are phylogenetically informative. One is a single nucleotide polymorphism resulting in CcoP truncation that acts as a molecular signature for the species N. meningitidis. We go on to show that the ancestral ccoP gene arose by a unique gene duplication and fusion event and is specifically and completely distributed within species of the genus Neisseria. Surprisingly, we found that strains engineered to express either of the two CcoP forms conditionally differed in their capacity to support nitrite-dependent, microaerobic growth mediated by NirK, a nitrite reductase. Thus, we propose that changes in CcoP domain architecture and ensuing alterations in function are key traits in successive, adaptive radiations within these metapopulations. These findings provide a dramatic example of how rare changes in core metabolic proteins can be connected to significant macroevolutionary shifts. They also show how evolutionary change at the molecular level can be linked to metabolic innovation and its reversal as well as demonstrating how genotype can be used to infer alterations of the fitness landscape within a single host

    The Contribution of Religiosity to Ideology:Empirical Evidences From Five Continents

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    The current study examines the extent to which religiosity account for ideological orientations in 16 countries from five continents (Australia, Brazil, Chile, Germany, Greece, Finland, Israel, Italy, Japan, Poland, Slovakia, Spain, Turkey, Ukraine, the United Kingdom, and the United States). Results showed that religiosity was consistently related to right and conservative ideologies in all countries, except Australia. This relation held across different religions, and did not vary across participant’s demographic conditions (i.e., gender, age, income, and education). After controlling for basic personal values, the contribution of religiosity on ideology was still significant. However, the effect was substantial only in countries where religion has played a prominent role in the public sphere, such as Spain, Poland, Greece, Italy, Slovakia, and Turkey. In the other countries, the unique contribution of religiosity was marginal or small

    An investigation in the correlation between Ayurvedic body-constitution and food-taste preference

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    An atlas of over 90.000 conserved noncoding sequences provides insight into crucifer regulatory regions

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    Despite the central importance of noncoding DNA to gene regulation and evolution, understanding of the extent of selection on plant noncoding DNA remains limited compared to that of other organisms. Here we report sequencing of genomes from three Brassicaceae species (Leavenworthia alabamica, Sisymbrium irio and Aethionema arabicum) and their joint analysis with six previously sequenced crucifer genomes. Conservation across orthologous bases suggests that at least 17% of the Arabidopsis thaliana genome is under selection, with nearly one-quarter of the sequence under selection lying outside of coding regions. Much of this sequence can be localized to approximately 90,000 conserved noncoding sequences (CNSs) that show evidence of transcriptional and post-transcriptional regulation. Population genomics analyses of two crucifer species, A. thaliana and Capsella grandiflora, confirm that most of the identified CNSs are evolving under medium to strong purifying selection. Overall, these CNSs highlight both similarities and several key differences between the regulatory DNA of plants and other species

    Linking the individual-level foraging interactions of piscivores to food-web dynamics in pelagic systems

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    Thesis (Ph.D.)--University of Washington, 2015Aquatic ecosystems are structured by environmental gradients, including temperature, depth, and water clarity. These gradients can mediate the strength of trophic interactions by influencing the distribution, physiology, and behavior of predators and prey. My dissertation addressed the following questions: 1) What factors determine the foraging success of pelagic piscivores during encounters with prey? and 2) How do temperature and depth mediate direct and indirect trophic interactions in lakes? First, I conducted feeding experiments to quantify the effects of turbidity and prey shoaling behavior on the foraging efficiency of Chinook salmon during encounters with Pacific herring. Chinook salmon successfully consumed herring during only 1-4% of encounters, limited by the rates of attacks per encounter and capture success (prey consumed per attack). Capture success declined with increasing turbidity and prey shoaling. These results indicate post-encounter processes can strongly limit feeding rates of pelagic piscivores and they provide the necessary parameters to incorporate these processes into foraging models. Second, I conducted field sampling in Lake Chelan, Washington to quantify how the strengths of trophic interactions between zooplankton, mysid shrimp, kokanee, and lake trout changed along environmental gradients. Bioenergetics and population models revealed strong predation impacts of lake trout on kokanee, which were initially masked from detection by ecological time lags. Mysids influenced kokanee through two negative indirect interactions, which differed in strength between contrasting lake basins. Mysids competed for zooplankton prey more strongly in a deeper, cooler basin due to their low thermal optimum. However, mysids provided greater energetic support to lake trout diet in a shallower basin, where lake trout were greater in density and inflicted greater predation risk on kokanee. A diel vertical migration model predicted mysids were more vulnerable to lake trout predation at shallower sites within the lake, and this prediction was supported by stable isotope analysis of lake trout diets. These findings revealed a mechanism by which mysids could cause greater food-web impacts in shallower systems where they are more vulnerable to predation. In conclusion, my results show strong associations between the physical environment, the behaviors of individual predators and prey, and the dynamics of populations and food webs
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