• Adding zooplankton to the OSMAC toolkit: Effect of grazing stress on the metabolic profile and bioactivity of a diatom 

      Osvik, Renate Døving; Ingebrigtsen, Richard Andre; Norrbin, Fredrika; Andersen, Jeanette Hammer; Eilertsen, Hans Christian; Hansen, Espen Holst (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-03)
      “One strain many compounds” (OSMAC) based approaches have been widely used in the search for bioactive compounds. Introducing stress factors like nutrient limitation, UV-light or cocultivation with competing organisms has successfully been used in prokaryote cultivation. It is known that diatom physiology is affected by changed cultivation conditions such as temperature, nutrient concentration and ...
    • Bioactivity of a Marine Diatom (Porosira glacialis [Grunow] Jorgensen 1905) Cultivated With and Without Factory Smoke CO2 

      Osvik, Renate Døving; Andersen, Jeanette Hammer; Eilertsen, Hans Christian; Genevière, Anne-Marie; Hansen, Espen Holst (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-16)
      Using industrial emissions as a strategy for CO<sub>2</sub> sequestration through carbon capture and utilization (CCU) in cultivation of microalgae can potentially change cultivation factors such as pH, nutrient availability and presence of trace metals, which could alter the growth and metabolism of the microalgae. It is therefore important to investigate whether such changes in culturing conditions ...
    • Chemical Diversity as a Function of Temperature in Six Northern Diatom Species 

      Huseby, Siv; Degerlund, Maria; Eriksen, Gunilla Kristina; Ingebrigtsen, Richard Andre; Eilertsen, Hans Christian; Hansen, Espen (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      In this study, we investigate how metabolic fingerprints are related to temperature. Six common northern temperate diatoms (Attheya longicornis, Chaetoceros socialis, Chaetoceros furcellatus, Porosira glacialis, Skeletonema marinoi, and Thalassiosira gravida) were cultivated at two different temperatures, 0.5 and 8.5 °C. To exclude metabolic variations due to differences in growth rates, the growth ...
    • Drivers of Atmosphere-Ocean CO2 Flux in Northern Norwegian Fjords 

      Aalto, Nerea Johanna; Campbell, Karley; Eilertsen, Hans Christian; Bernstein, Hans Christopher (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-07-07)
      High-latitude fjords and continental shelves are shown to be sinks for atmospheric CO2, yet large spatial-temporal variability and poor regional coverage of sea-air CO2 flux data, especially from fjord systems, makes it difficult to scale our knowledge on how they contribute to atmospheric carbon regulation. The magnitude and seasonal variability of atmosphere-sea CO2 flux was investigated in ...
    • The Effect of Freeze/Thaw Cycles on Reproducibility of Metabolic Profiling of Marine Microalgal Extracts Using Direct Infusion High-Resolution Mass Spectrometry (HR-MS) 

      Eilertsen, Hans Christian; Huseby, Siv; Degerlund, Maria; Eriksen, Gunilla Kristina; Ingebrigtsen, Richard Andre; Hansen, Espen (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-10-13)
      During normal sample preparation, storage in freezers and subsequent freeze/thaw cycles are commonly introduced. The effect of freeze/thaw cycles on the metabolic profiling of microalgal extracts using HR-MS was investigated. Methanolic extracts of monocultures of Arctic marine diatoms were analyzed immediately after extraction, after seven days of storage at −78 °C (one freeze/thaw cycle), and after ...
    • Field sampling marine plankton for biodiscovery 

      Ingebrigtsen, Richard Andre; Hansen, Espen; Andersen, Jeanette Hammer; Eilertsen, Hans Christian (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-20)
      Microalgae and plankton can be a rich source of bioactivity. However, induction of secondary metabolite production in lab conditions can be difficult. One simple way of bypassing this issue is to collect biomass in the field and screen for bioactivity. Therefore, bulk net samples from three areas along the coast of northern Norway and Spitsbergen were collected, extracted and fractionated. ...
    • Genetic Inactivation of European Sea Bass (Dicentrarchus labrax L.) Eggs Using UV-Irradiation: Observations and Perspectives 

      Colléter, Julie; Penman, David J; Lallement, Stephane; Fauvel, Christian; Hanebrekke, Tanja Lexau; Osvik, Renate Døving; Eilertsen, Hans Christian; D'Cotta, Helena; Chatain, Beatrice; Peruzzi, Stefano (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
      Androgenesis is a form of uniparental reproduction leading to progenies inheriting only the paternal set of chromosomes. It has been achieved with variable success in a number of freshwater species and can be attained by artificial fertilization of genetically inactivated eggs following exposure to gamma (γ), X-ray or UV irradiation (haploid androgenesis) and by restoration of diploidy by suppression ...
    • In vivo exposure to northern diatoms arrests sea urchin embryonic development 

      Gudimova, Elena; Eilertsen, Hans Christian; Jørgensen, Trond Ø.; Hansen, Espen (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-01)
      There are numerous reports indicating that marine diatoms may act harmful to early developmental stages of invertebrates. It is believed that the compounds responsible for these detrimental effects are oxylipins resulting from oxidized polyunsaturated fatty acids, and that they may function as grazing deterrents. Most studies reporting these effects have exposed test organisms to diatom extracts or ...
    • Inclusion of photoautotrophic cultivated diatom biomass in salmon feed can deter lice 

      Eilertsen, Hans Christian; Elvevoll, Edel O.; Giæver, Ingeborg Hulda; Svenning, Jon Brage; Dalheim, Lars; Svalheim, Ragnhild Aven; Vang, Birthe; Siikavuopio, Sten Ivar; Dragøy, Ragnhild; Ingebrigtsen, Richard Andre; Hansen, Espen Holst; Hustad, Anette; Eilertsen, Karl-Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-07-29)
      The aim of this study was to evaluate the potential of diatom (microalgae) biomass as a lice-reducing ingredient in salmon feed. The original hypothesis was based on the fact that polyunsaturated aldehydes (PUAs), e.g. 2-trans, 4-trans decadenial (A3) produced by diatoms can function as grazing deterrents and harm copepod development. Salmon lice (Lepeophtheirus salmonis) is a copepod, and we intended ...
    • Light and temperature effects on bioactivity in diatoms 

      Ingebrigtsen, Richard Andre; Hansen, Espen; Andersen, Jeanette hammer; Eilertsen, Hans Christian (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-06-05)
      Isolates of five pelagic North Atlantic marine diatoms (Bacillariophyceae): Attheya longicornis, Chaetoceros socialis, Chaetoceros furcellatus, Skeletonema marinoi and Porosira glacialis were cultivated in large photobioreactors at two light and two temperature regimes to test if this affected bioactivity. We screened for bioactivity in assays representing five different therapeutic areas: ...
    • Lipid content and fatty acid composition of Porosira glacialis and Attheya longicornis in response to carbon dioxide (CO2) aeration 

      Artamonova, Elena; Vasskog, Terje; Eilertsen, Hans Christian (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-05-18)
      In the current study two novel psychrophilic diatoms Porosira glacialis and Attheya longicornis were tested for suitability to CO2 mitigation coupled with production of the physiologically requisite omega± 3 fatty acids. This study is in line with the worldwide conducted research aimed at applying biorefinery concept to heavy polluting industries. Since the production of algal high value compounds, ...
    • Mass Cultivation of Microalgae: I. Experiences with Vertical Column Airlift Photobioreactors, Diatoms and CO2 Sequestration 

      Eilertsen, Hans Christian; Eriksen, Gunilla; Bergum, John-Steinar; Strømholt, Jo; Elvevoll, Edel O.; Eilertsen, Karl-Erik; Heimstad, Eldbjørg Sofie; Giæver, Ingeborg Hulda; Israelsen, Linn; Svenning, Jon Brage; Dalheim, Lars; Osvik, Renate Døving; Hansen, Espen Holst; Ingebrigtsen, Richard Andre; Aspen, Terje M; Wintervoll, Geir-Henning (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-17)
      From 2015 to 2021, we optimized mass cultivation of diatoms in our own developed vertical column airlift photobioreactors using natural and artificial light (LEDs). The project took place at the ferrosilicon producer Finnfjord AS in North Norway as a joint venture with UiT—The Arctic University of Norway. Small (0.1–6–14 m<sup>3</sup>) reactors were used for initial experiments and to produce inoculum ...
    • Mikroalger i fôr, ny løsning for å redusere lusepåslag på laks – Faglig sluttrapport 

      Hustad, Anette; Vang, Birthe; Eilertsen, Hans Christian; Siikavuopio, Sten Ivar; Sæther, Bjørn-Steinar; Svalheim, Ragnhild Aven; Hansen, Espen Holst; Svenning, Jon Brage; Kousoulaki, Katerina; Whitaker, Ragnhild (Research report; Forskningsrapport, 2020-05)
      I dette prosjektet har vi testet ut en hypotese om at ved å erstatte vegetabilske oljer i fôr til oppdrettslaks med marine oljer, vil man kunne redusere lusepåslag hos laks. Vi har fôret laks med fire ulike fôr, der proteininnholdet er det samme, men oljen er variert. De ulike fôrene vi brukte var kontrollfôr som var standardfôr med vegetabilsk olje, og tre ulike testfôr der vegetabilsk olje ble ...
    • Stability of lipids during wet storage of the marine diatom Porosira glacialis under semi-preserved conditions at 4 and 20 °C 

      Dalheim, Lars; Svenning, Jon Brage; Vasskog, Terje; Eilertsen, Hans Christian; Olsen, Ragnar Ludvig (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-10-17)
      Cultivation of diatoms may help alleviate the pressure on wild fish stocks for marine nutrient availability in aquaculture feed and for human consumption. However, the lipids in microalgae biomass are easily deteriorated, both trough lipolysis and degradation of polyunsaturated fatty acids (PUFA). Proper storage conditions are therefore necessary to maintain the lipid quality. Additionally, the ...
    • Structural and functional analyses of Rubisco from arctic diatom species reveal unusual posttranslational modifications 

      Valegård, Karin; Andralojc, P. John; Haslam, Richard P.; Pearce, F. Grant; Eriksen, Gunilla Kristina; Madgwick, Pippa J.; Kristoffersen, Anne Karin; van Lun, Michiel; Klein, Uwe; Eilertsen, Hans Christian; Parry, Martin A.J.; Andersson, Inger (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-20)
      The catalytic performance of the major CO<sub>2</sub>-assimilating enzyme, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), restricts photosynthetic productivity. Natural diversity in the catalytic properties of Rubisco indicates possibilities for improvement. Oceanic phytoplankton contain some of the most efficient Rubisco enzymes, and diatoms in particular are responsible for a significant ...
    • Temperature dependent growth rate, lipid content and fatty acid composition of the marine cold-water diatom Porosira glacialis 

      Svenning, Jon Brage; Dalheim, Lars; Eilertsen, Hans Christian; Vasskog, Terje (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-27)
      In this study, the northern cold-water marine diatom <i>Porosira glacialis</i> was cultivated in a pilot-scale mass cultivation system at 5 different temperatures (−2 to 12 °C), in order to evaluate temperature-dependent growth rate (in vitro Chl <i>a</i>), lipid content (Folch's method) and fatty acid (FA) composition (GC–MS) in the exponential growth phase. We found that <i>P. glacialis</i> has a ...
    • Two Isomeric C16 Oxo-Fatty Acids from the Diatom Chaetoceros karianus Show Dual Agonist Activity towards Human Peroxisome Proliferator-Activated Receptors (PPARs) α/γ 

      Moldes-Anaya, Angel; Sæther, Thomas; Uhlig, Silvio; Nebb, Hilde Irene; Larsen, Terje; Eilertsen, Hans Christian; Paulsen, Steinar Martin (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-05-25)
      The peroxisome proliferator-activated receptors (PPARs) function as ligand-activated transcription factors that convert signals in the form of lipids to physiological responses through the activation of metabolic target genes. Due to their key roles in lipid and carbohydrate metabolism, the PPARs are important drug targets. However, for several of the PPAR drugs currently in use, adverse side effects ...