Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2012
Forfattere
Julia Schregel Alexander Kopatz Snorre Hagen Henrik Brøseth Martin Smith Steinar Wikan Ingvild Wartiainen Paul Eric Aspholm Jouni Aspi Jon Swenson O. Makarova Natalia Polikarpova Michael Schneider Per Knappskog Minna Ruokonen Ilpo Kojola Konstantin F. Tirronen Pjotr I. Danilov Hans Geir EikenSammendrag
Noninvasively collected genetic data can be used to analyse large-scale connectivity patterns among populations of large predators without disturbing them, which may contribute to unravel the species’ roles in natural ecosystems and their requirements for long-term survival. The demographic history of brown bears (Ursus arctos) in Northern Europe indicates several extinction and recolonization events, but little is known about present gene flow between populations of the east and west. We used 12 validated microsatellite markers to analyse 1580 hair and faecal samples collected during six consecutive years (2005–2010) in the Pasvik Valley at 70_N on the border of Norway, Finland and Russia. Our results showed an overall high correlation between the annual estimates of population size (Nc), density (D), effective size (Ne) and Ne ⁄Nc ratio. Furthermore, we observed a genetic heterogeneity of _0.8 and high Ne ⁄Nc ratios of _0.6, which suggests gene flow from the east. Thus, we expanded the population genetic study to include Karelia (Russia, Finland), Va¨sterbotten (Sweden) and Troms (Norway) (477 individuals in total) and detected four distinct genetic clusters with low migration rates among the regions. More specifically, we found that differentiation was relatively low from the Pasvik Valley towards the south and east, whereas, in contrast, moderately high pairwise FST values (0.91–0.12) were detected between the east and the west. Our results indicate ongoing limits to gene flow towards the west, and the existence of barriers to migration between eastern and western brown bear populations in Northern Europe.
Forfattere
Lars Sandved DalenSammendrag
En liten overhøvling: I DNs artikkel om Barkevik Bruk 14. juni dukker to feilstavede barkbiller opp. Uansett hva Øystein Sundes «Barkebille Boogie» lærte oss å si, staves ordet barkbille uten e i midten. Rett skal være rett, ikke minst når det gjelder profilerte lister.
Forfattere
Reidun PommerescheSammendrag
Foredrag og omvisning om nyttedyr, skadegjørere, snegler, edderkopper og meitemark i kjøkkenhagen.
Forfattere
Till SeehusenSammendrag
Det er ikke registrert sammendrag
Forfattere
Carl Gunnar Fossdal Nadeem Yaqoob Paal Krokene Harald Kvaalen Halvor Solheim Igor A. YakovlevSammendrag
Background: NB-LRR resistance proteins are involved in recognizing pathogens and other exogenous stressors in plants. Resistance proteins are the first step in induced defence responses and a better understanding of their regulation is important to understand the mechanisms of plant defence. Much of the post-transcriptional regulation in plants is controlled by microRNAs (miRNA). We examined the expression of five Norway spruce miRNA that may regulate NB-LRR related transcripts in secondary phloem (bark) of resistant Norway spruce after wounding and inoculation with the necrotrophic blue stain fungus Ceratocystis polonica. Results: The plants of this clone recovered from both the pathogen inoculations and wounding alone. We found local and systemic induction of the resistance marker genes PaChi4, PaPAL and PaPX3 indicative of an effective induced host defence response. There were minor local and systemic changes in the expression of five miRNAs and 21 NB-LRRs between healthy and treated plants. Only five putative NB-LRRs (PaLRR1, PaLRR3, PaLRR14, PaLRR15 and PaLRR16) showed significant increases greater than two-fold as a local response to C. polonica. Of all NB-LRRs only PaLRR3, the most highly differentially regulated NB-LRR, showed a significant increase also due to wounding. The five miRNAs showed indications of an initial local and systemic down-regulation at day 1, followed by a later increase up to and beyond the constitutive levels at day 6. However, the initial down-regulation was significant only for miR3693 and miR3705. Conclusions: Overall, local and systemic expression changes were evident only for the established resistance marker genes and PaLRR3. The minor expression changes observed both for the followed miRNAs and their predicted NB-LRR targets suggest that the expression of most NB-LRR genes are maintained close to their constitutive levels in stressed and healthy Norway spruce plants.
Forfattere
Karen Refsgaard Ingrid GuldvikSammendrag
Det er ikke registrert sammendrag
Forfattere
Sheng-Hong Li Nina Elisabeth Nagy Almuth Hammerbacher Paal Krokene Xue-Mei Niu Jonathan Gershenzon Bernd SchneiderSammendrag
Norway spruce (Picea abies) bark contains specialized phloem parenchyma cells that swell and change their contents upon attack by the bark beetle Ips typographus and its microbial associate, the blue stain fungus Ceratocystis polonica. These cells exhibit bright autofluorescence after treatment with standard aldehyde fixatives, and so have been postulated to contain phenolic compounds. Laser microdissection of spruce bark sections combined with cryogenic NMR spectroscopy demonstrated significantly higher concentrations of the stilbene glucoside astringin in phloem parenchyma cells than in adjacent sieve cells. After infection by C. polonica, the flavonoid (+)-catechin also appeared in phloem parenchyma cells and there was a decrease in astringin content compared to cells from uninfected trees. Analysis of whole-bark extracts confirmed the results obtained from the cell extracts and revealed a significant increase in dimeric stilbene glucosides, both astringin and isorhapontin derivatives (piceasides A to H), in fungus-infected versus uninfected bark that might explain the reduction in stilbene monomers. Phloem parenchyma cells thus appear to be a principal site of phenolic accumulation in spruce bark.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Lone Ross Gobakken Mats WestinSammendrag
Environmentally sound wooden facades with long service lives and acceptable appearance are desired. Several types of modified wood are used in building applications to fulfil those requirements, but there is a potential for using more modified wood material. In facades modified wood are often used without any surface treatment or coating, but some sort of coating are desired and requested in a segment of the potential marked. Finding suitable coating systems for modified wood can be a challenge, and the objective of this study was to evaluate the long time performance of modified wood substrates in combinations with different coating systems after 8 years of outdoors exposure. Furthermore, evaluations at 4 and 8 years were compared to study the quantitative mould growth in a very late stage of the test period to capture any deviant behaviour from the traditional growth curve. Three coating systems were applied on furfurylated Scots pine, acetylated Scots pine, thermally modified Scots pine, oil/thermally modified Scots pine, thermally modified Norway spruce, and three reference wood substrates, and exposed outdoors for 8 years to evaluate their ability to resist surface moulds and blue stain fungi, cracking and flaking. The test was carried out according to EN 927-3. After 8 years mould growth, cracking and flaking mainly varied with type of coating where the tendency was that a waterborne system had the lowest rating for both mould growth, cracking and flaking. Oil/thermally modified treated pine had the lowest mould rating of the modified substrates. Acetylated pine had a decrease in mould rating from year 4 to year 8 when coated with the best coating system and a very small increase when coated with the second best system. Acetylated pine tended to have less flaking than the other modified substrates. Furthermore, acetylated pine, thermally modified pine and thermally modified spruce tended to have the least cracking of the modified wood substrates.
Forfattere
Christer MagnussonSammendrag
Det er ikke registrert sammendrag