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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.

2019

Sammendrag

The populations sizes of Ips typographus in Norway have been monitored since the last big outbreak period in the 1970s. By now the monitoring programme includes about 500 pheromone-baited trap records for each of the last 40 years. Normally, Ips typographus has been the only species of major concern in northern bark beetle outbreaks, and trapping records have served as a warning when the over-wintering population sizes are large. In contrast to Central Europe, the regional trend in northwest is that rainy weather tend to slow down the bark beetle populations in many years, whereas stormfelling episodes of spruces, snowbreaks and warm and dry seasons in certain years favour Ips typographus and other bark beetle species. Recent observations indicate that other less aggressive bark beetle species may play a more important role during severe drought periods that follow rainful seasons with low production of Ips typographus. It is likely that an increased frequency of extreme weather events may have unexpected effects on what bark beetles become abundant during the course of the outbreaks. Furthermore, the warm years seem to be especially favourable for the Ips typographus at the northernmost latitudes. In addition, a new bark beetle species for Scandinavia, Ips amitinus, is expanding its range and may become a participant in future bark beetle outbreaks in this region.

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Sammendrag

Sustainable production of biofuels from lignocellulose feedstocks depends on cheap enzymes for degradation of such biomass. Plants offer a safe and cost‐effective production platform for biopharmaceuticals, vaccines and industrial enzymes boosting biomass conversion to biofuels. Production of intact and functional protein is a prerequisite for large‐scale protein production, and extensive host‐specific post‐translational modifications (PTMs) often affect the catalytic properties and stability of recombinant enzymes. Here we investigated the impact of plant PTMs on enzyme performance and stability of the major cellobiohydrolase TrCel7A from Trichoderma reesei, an industrially relevant enzyme. TrCel7A was produced in Nicotiana benthamiana using a vacuum‐based transient expression technology, and this recombinant enzyme (TrCel7Arec) was compared with the native fungal enzyme (TrCel7Anat) in terms of PTMs and catalytic activity on commercial and industrial substrates. We show that the N‐terminal glutamate of TrCel7Arec was correctly processed by N. benthamiana to a pyroglutamate, critical for protein structure, while the linker region of TrCel7Arec was vulnerable to proteolytic digestion during protein production due to the absence of O‐mannosylation in the plant host as compared with the native protein. In general, the purified full‐length TrCel7Arec had 25% lower catalytic activity than TrCel7Anat and impaired substrate‐binding properties, which can be attributed to larger N‐glycans and lack of O‐glycans in TrCel7Arec. All in all, our study reveals that the glycosylation machinery of N. benthamiana needs tailoring to optimize the production of efficient cellulases.

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Sammendrag

Standardized tools are needed to identify and prioritize the most harmful non-native species (NNS). A plethora of assessment protocols have been developed to evaluate the current and potential impacts of non-native species, but consistency among them has received limited attention. To estimate the consistency across impact assessment protocols, 89 specialists in biological invasions used 11 protocols to screen 57 NNS (2614 assessments). We tested if the consistency in the impact scoring across assessors, quantified as the coefficient of variation (CV), was dependent on the characteristics of the protocol, the taxonomic group and the expertise of the assessor. Mean CV across assessors was 40%, with a maximum of 223%. CV was lower for protocols with a low number of score levels, which demanded high levels of expertise, and when the assessors had greater expertise on the assessed species. The similarity among protocols with respect to the final scores was higher when the protocols considered the same impact types. We conclude that all protocols led to considerable inconsistency among assessors. In order to improve consistency, we highlight the importance of selecting assessors with high expertise, providing clear guidelines and adequate training but also deriving final decisions collaboratively by consensus.

Sammendrag

Mange ugress produserer naturlig giftstoffer (plantetoksiner) som beskyttelse mot skadegjørere som insekter og planteetere. Dersom disse følger med under innhøstingen av matplantene, kan det føre til at helseskadelige plantetoksiner havner i maten vår. Tropane alkaloider finnes i store mengder i ugressfrø fra planter i piggepleslekten. Avlinger kan bli forurenset med disse frøene ved innhøsting, og tropane alkaloider kan derfor være et problem i korn- og frøbasert mat. Pyrrolizidine alkaloider (PA) finnes ofte i ugress i tropiske og sub-tropiske strøk, og te fra slike områder kan potensielt inneholde PA. Honning kan også inneholde PA dersom biene samler nektar fra PA-produserende planter. For å få en indikasjon på nivå av tropane alkaloider og PA i mat, har Mattilsynet tatt prøver av aktuelle matvarer solgt på det norske markedet i 2018. Prøvene er analysert av Norsk institutt for bioøkonomi (NIBIO). Det tropane alkaloidet atropin ble funnet i 4 av 14 prøver av kornbasert barnemat, mens et annet, skopolamin, ble påvist i to av prøvene. I likhet med i 2017, ble de høyeste funnene gjort i skumpinner, hvor en av prøvene var over grenseverdien på 1 µg/kg. PA ble funnet i 8 av 10 prøver av te; de høyeste nivåene ble målt i grønn te. PA’ene jacobine og jacobineNOX ble målt i svært høye nivåer i en av prøvene. I honning ble det funnet PA i 9 av 15 prøver, og kun i lave nivåer.