Viser treff 1301-1320 av 5233

    • Gene expression of lactobacilli in murine forestomach biofilms 

      Schwab, Clarissa; Tveit, Alexander Tøsdal; Schleper, Christa; Urich, Tim (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-04-04)
      Lactobacilli populate the gastro-intestinal tract of vertebrates, and are used in food fermentations and as probiotics. Lactobacilli are also major constituents of stable biofilms in the forestomach of rodents. In order to investigate the lifestyle of these biofilm lactobacilli in C57BL/6 mice, we applied metatranscriptomics to analyse gene expression (assessed by mRNA) and community composition ...
    • Shifting mirrors: adaptive changes in retinal reflections to winter darkness in Arctic reindeer 

      Stokkan, Karl-Arne; Folkow, Lars; Dukes, Juliet; Neveu, Magella; Hogg, Chris R; Siefken, Sandra Katharina Christiane; Dakin, Steven C; Jeffery, Glen (Journal article; Tidsskriftartikkel; Peer reviewed, 2013-12-22)
      Arctic reindeer experience extreme changes in environmental light from continuous summer daylight to continuous winter darkness. Here, we show that they may have a unique mechanism to cope with winter darkness by changing the wavelength reflection from their tapetum lucidum (TL). In summer, it is golden with most light reflected back directly through the retina, whereas in winter it is deep ...
    • Why Rudolph's nose is red: observational study 

      Ince, Can; van Kuijen, Anne-Marie; Milstein, Dan M J; Yürük, Koray; Folkow, Lars; Fokkens, Wytske J; Blix, Arnoldus S (Journal article; Tidsskriftartikkel, 2012-12-17)
      Objective To characterise the functional morphology of the nasal microcirculation in humans in comparison with reindeer as a means of testing the hypothesis that the luminous red nose of Rudolph, one of the most well known reindeer pulling Santa Claus’s sleigh, is due to the presence of a highly dense and rich nasal microcirculation.<p> <p>Design Observational study.<p> <p>Setting Tromsø, ...
    • Fish Skin and Gill Mucus: A Source of Metabolites for Non-Invasive Health Monitoring and Research 

      Ivanova, Lada; Rangel-Huerta, Oscar Daniel; Tartor, Haitham; Gjessing, Mona Cecilie; Dahle, Maria; Uhlig, Silvio (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-31)
      Mucous membranes such as the gill and skin mucosa in fish protect them against a multitude of environmental factors. At the same time, changes in the molecular composition of mucus may provide valuable information about the interaction of the fish with their environment, as well as their health and welfare. In this study, the metabolite profiles of the plasma, skin and gill mucus of freshwater ...
    • Robuste sjømatinntekter også under COVID-19 pandemien 

      Bertheussen, Bernt Arne (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-09)
      Norge er verdens nest største eksportør av sjømat. Inntektene skaper arbeid og aktivitet i lokalsamfunn langs hele kysten. Denne studien undersøker hvor sårbare inntektene til sjømatnæringen har vært under Covid-19 pandemien som har preget mesteparten av 2020 og hele 2021. I tillegg til å analysere inntektsutviklingen på aggregert nivå for fiskeri og havbruk, presenterer studien sektorvise analyser ...
    • Resemblance Reporting on Children: Sisters Are More Proactive than Brothers 

      Fisktjønmo, Guro Hole; Bårdsen, Bård-Jørgen; Folstad, Ivar (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-02)
      The asymmetric grandparental investment in humans may ultimately be explained by the paternity uncertainty hypothesis. The proximate mechanisms leading to grandparental bias in investment in grandchildren are, however, unclear. In a study of 233 males and females with an opposite sexed sibling, we examined whether comments on resemblance regarding one’s own child, or one’s sibling’s child, ...
    • Immobilization of muskoxen (Ovibos moschatus) with etorphine and xylazine 

      Blix, Arnoldus S; Lian, Hans; Ness, john (Journal article; Tidsskriftartikkel; Peer reviewed, 2011-06-27)
      One hundred and thirty three “wild” muskoxen, 81 of which of known body mass, were successfully immobilized using etorphine (M99), and xylazine (Rompun®), delivered by use of a dart gun. A dose of 0.05 mg/kg M99, supplemented by 0.15 mg/kg Rompun was found to be very effective. This dose is much higher than currently recommended e.g. by Handbook of Wildlife Chemical Immobilization.
    • Tundra vegetation ecology from the sky - Aerial images and photogrammetry as tools to monitor landscape change 

      Eischeid, Isabell (Doctoral thesis; Doktorgradsavhandling, 2022-05-24)
      Long-term temperature increases, higher frequencies of extreme weather events and changes in food web structures will all affect the state of Arctic tundra ecosystems at different temporal and spatial scales. Ecologists are tasked with understanding these biotic and abiotic interactions and finding methods to measure them. This thesis applies new technology and methods within the principles of ...
    • Upregulation of tryptophanyl-tRNA synthethase adapts human cancer cells to nutritional stress caused by tryptophan degradation 

      Adam, Isabell; Dewi, Dyah L.; Mooiweer, Joram; Sadik, Ahmed; Mohapatra, Soumya R.; Berdel, Bianca; Keil, Melanie; Sonner, Jana K.; Thedieck, Kathrin; Rose, Adam J.; Platten, Michael; Heiland, Ines; Trump, Saskia; Opitz, Christiane A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-09-05)
      Tryptophan (Trp) metabolism is an important target in immuno-oncology as it represents a powerful immunosuppressive mechanism hijacked by tumors for protection against immune destruction. However, it remains unclear how tumor cells can proliferate while degrading the essential amino acid Trp. Trp is incorporated into proteins after it is attached to its tRNA by tryptophanyl-tRNA synthestases. As ...
    • Herbivore Effects on Ecosystem Process Rates in a Low-Productive System 

      Tuomi, Maria Wilhelmina; Stark, Sari; Hoset, Katrine Skamfer; Väisänen, Maria; Oksanen, Lauri; Murguzur, Francisco Javier Ancin; Tuomisto, Hanna; Dahlgren, Jonas; Bråthen, Kari Anne (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-10-17)
      Mammalian herbivores shape the structure and function of many nutrient-limited or low-productive terrestrial ecosystems through modification of plant communities and plant–soil feedbacks. In the tundra biome, mammalian herbivores may both accelerate and decelerate plant biomass growth, microbial activity and nutrient cycling, that is, ecosystem process rates. Selective foraging and associated ...
    • How to tame a parasite - Developing biotechnological pipelines for gene function studies in Cuscuta 

      Lachner, Lena Anna-Maria (Doctoral thesis; Doktorgradsavhandling, 2022-05-20)
      <p><i>Cuscuta</i> is a genus of parasitic plants that form cross-species bridges and connect to the xylem and phloem of a wide variety of host plants. Because of their unique lifestyle, research into processes like the formation of connections in between plant cells and plant immunity would benefit from <i>Cuscuta</i> as a model system. However, a method to study gene functions in a <i>Cuscuta</i> ...
    • Hooded seal (Cystophora cristata) pups ingest snow and seawater during their post-weaning fast 

      Schots, Pauke Carlijn; Bue, Marie Emilie Sørdal; Nordøy, Erling Sverre (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-11-09)
      The purpose of this study was to evaluate the importance of exogenous water intake (snow/seawater) in hooded seal (Cystophora cristata) pups during their postweaning fast. In this study, five hooded seal pups had ad lib access to snow and seawater for the first 12 and last 21 days of their post-weaning fast, respectively. Total body water and water flux were determined during both exposure periods ...
    • Machine learning for classification of an eroding scarp surface using terrestrial photogrammetry with nir and rgb imagery 

      Bernsteiner, H.; Brozova, N.; Eischeid, Isabell; Hamer, A.; Haselberger, S.; Huber, M.; Kollert, A.; Vandyk, T. M.; Pirotti, F. (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-03)
      Increasingly advanced and affordable close-range sensing techniques are employed by an ever-broadening range of users, with varying competence and experience. In this context a method was tested that uses photogrammetry and classification by machine learning to divide a point cloud into different surface type classes. The study site is a peat scarp 20 metres long in the actively eroding river bank ...
    • Effect of glacial drainage water on the CO2 system and ocean acidification state in an Arctic tidewater-glacier fjord during two contrasting years 

      Fransson, Agneta Ingrid; Chierici, Melissa; Nomura, Daiki; Granskog, Mats A.; Kristiansen, Svein; Martma, Tõnu; Nehrke, Gernot (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-02-03)
      In order to investigate the effect of glacial water on the CO<sub>2</sub> system in the fjord, we studied the variability of the total alkalinity (A<sub>T</sub>), total dissolved inorganic carbon (C<sub>T</sub>), dissolved inorganic nutrients, oxygen isotopic ratio (δ<sup>18</sup>O), and freshwater fractions from the glacier front to the outer Tempelfjorden on Spitsbergen in winter 2012 (January, ...
    • Distribution, density and abundance of Antarctic ice seals off Queen Maud Land and the eastern Weddell Sea 

      Gurarie, Eliezer; Bengtson, John L; Bester, MN; Blix, Arnoldus S; Cameron, Michael; Bornemann, Horst; Nordøy, Erling Sverre; Plötz, Joachim; Steinhage, Daniel; Boveng, Peter (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-09-09)
      The Antarctic Pack Ice Seal (APIS) Program was initiated in 1994 to estimate the abundance of four species of Antarctic phocids: the crabeater seal Lobodon carcinophaga, Weddell seal Leptonychotes weddellii, Ross seal Ommatophoca rossii and leopard seal Hydrurga leptonyx and to identify ecological relationships and habitat use patterns. The Atlantic sector of the Southern Ocean (the eastern ...
    • Determinants of parasite distribution in Arctic charr populations: catchment structure versus dispersal potential 

      Paterson, Rachel Anne; Knudsen, Rune; Blasco-Costa, Isabel; Dunn, Alison M; Hytterød, Sigurd; Hansen, Haakon (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-18)
      Parasite distribution patterns in lotic catchments are driven by the combined influences of unidirectional water flow and the mobility of the most mobile host. However, the importance of such drivers in catchments dominated by lentic habitats are poorly understood. We examined parasite populations of Arctic charr Salvelinus alpinus from a series of linear-connected lakes in northern Norway to ...
    • High Arctic Mytilus spp.: occurrence, distribution and history of dispersal 

      Leopold, Peter; Renaud, Paul Eric; Ambrose, William G; Berge, Jørgen (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-10-16)
      Many marine species are known to change their distribution in response to changing climatic conditions. One such example is the blue mussel Mytilus spp., spreading northward coincident with an increase in ocean temperatures. On Svalbard, the frst living specimens of Mytilus spp. were discovered in 2004. Here we present an analysis of the current distribution of Mytilus spp. on Svalbard, with a ...
    • Freshwater and its role in the Arctic Marine System: Sources, disposition, storage, export, and physical and biogeochemical consequences in the Arctic and global oceans 

      Carmack, Eddy C.; Yamamoto-Kawai, Michiyo; Haine, Thomas W.N.; Bacon, Sheldon; Bluhm, Bodil; Lique, Camille; Melling, Humfrey; Polyakov, Igor V.; Straneo, Fiamma; Timmermans, Mary Louise E.; Williams, William J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-11)
      The Arctic Ocean is a fundamental node in the global hydrological cycle and the ocean’s thermohaline circulation. We here assess the system’s key functions and processes: (1) the delivery of fresh and low-salinity waters to the Arctic Ocean by river inflow, net precipitation, distillation during the freeze/thaw cycle, and Pacific Ocean inflows; (2) the disposition (e.g., sources, pathways, and ...
    • Fishes in a changing world: learning from the past to promote sustainability of fish populations 

      Gordon, Timothy A.C.; Harding, Harry R.; Clever, Friederike K.; Davidson, Isla Keesje; Davison, William; Montgomery, Daniel W.; Weatherhead, Rebekah C.; Windsor, Fredric M.; Armstrong, John D.; Bardonnet, Agnès; Bergman, Eva; Britton, John Robert; Côté, Isabelle M.; D'agostino, Daniele; Greenberg, Larry; Harborne, Alastair R.; Kahilainen, Kimmo Kalevi; Metcalfe, Neil B.; Mills, Suzanne C.; Milner, Nigel J.; Mittermayer, Felix H.; Montorio, Lucie; Nedelec, Sophie L.; Prokkola, Jenni M.; Rutterford, Louise A.; Salvanes, Anne Gro Vea; Simpson, Stephen D.; Vainikka, Anssi; Pinnegar, John Keith; Santos, Eduarda M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-14)
      Populations of fishes provide valuable services for billions of people, but face diverse and interacting threats that jeopardize their sustainability. Human population growth and intensifying resource use for food, water, energy and goods are compromising fish populations through a variety of mechanisms, including overfishing, habitat degradation and declines in water quality. The important ...
    • Evolution of seasonal adaptations in voles - a physiological and genetic approach 

      Van Dalum, Mattis Jayme (Doctoral thesis; Doktorgradsavhandling, 2022-05-06)
      <p>This thesis addressed phenotypic and genetic variation in seasonal time keeping mechanisms of the tundra vole (<i>Microtus oeconomus</i>) and the common vole (<i>Microtus arvalis</i>). Voles (<i>Microtus</i>) are short-lived, non-hibernating and seasonally breeding rodents. The genus has rapidly evolved (< 2 million years) into one of the most speciose mammalian genera (Sitnikova et al. 2007; ...