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.
2009
Forfattere
Aksel DøvingSammendrag
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Forfattere
Kristine Marie Olsen Rune Slimestad Unni Synnøve Lea Cato Brede Trond Karsten Løvdal Peter Ruoff Michel Verheul Cathrine LilloSammendrag
The flavonoid pathway is known to be up-regulated by different environmental stress factors. Down-regulation of the pathway is much less studied and is emphasized in the present work. Flavonoid accumulation was induced by exposing plants for 1 week to nitrogen depletion at 10 degrees C, giving high levels of anthocyanins and 3-glucoside-7-rhamnosides, 3,7-di-rhamnosides and 3-rutinoside-7-rhamnosides of kaempferol and quercetin. Flavonol accumulation as influenced by temperatures and nitrogen supply was not related to the glycosylation patterns but to the classification as quercetin and kaempferol. When nitrogen was re-supplied, transcripts for main regulators of the pathway, PAP1/GL3 and PAP2/MYB12, fell to less than 1 and 0.1% of initial values, respectively, during 24 h in the 15-30 degrees C temperature range. Anthocyanins showed a half-life of approximately 1 d, while the degradation of flavonols was much slower. Interestingly, the initial fluxes of anthocyanin and flavonol degradations were found to be temperature-independent. A kinetic model for the flavonoid pathway was constructed. In order to get the observed concentration-temperature profiles as well as the temperature compensation in the flavonoid degradation flux, the model predicts that the flavonoid pathway shows an increased temperature sensitivity at the end of the pathway, where the up-regulation by PAP/GL3 has been found to be largest.
Forfattere
Dugassa N. Feyissa Trond Karsten Løvdal Kristine Marie Olsen Rune Slimestad Cathrine LilloSammendrag
The bHLH transcription factors EGL3 (ENHANCER OF GLABRA3) and its close homologue GL3 (GLABRA3) are important regulators of the anthocyanin pathway in Arabidopsis thaliana, and together with TTG1 (a WD40 repeat protein) and MYB transcription factors regulate specific genes in the pathway. In response to nitrogen depletion, the MYB genes PAP1/PAP2 (production of anthocyanin pigment 1/2) and GL3 are strongly induced, and anthocyanin synthesis is activated in seedlings and rosette stage plants. In this study we show that anthocyanins accumulate in both wild type and egl3, but not in gl3 loss-of-function mutants when depleted of nitrogen. Several structural genes of flavonoid metabolism including CHS (chalcone synthase), FLS1 (flavonol synthase 1) and ANS (anthocyanidin synthase) were induced in response to nitrogen depletion in wild type as well as in the egl3 and gl3 mutants. Strikingly, in the gl3 mutant DFR (dihydroflavonol-4-reductase) transcript level was only 2% of the levels in wild type or egl3 mutant. Hence, low expression of DFR appears to be the bottleneck preventing anthocyanin synthesis in the gl3 mutant. The specific effect on DFR, but not ANS is compatible with involvement of the MYBL2 inhibitor.
Forfattere
Jan Inge Jenssen Erlend NybakkSammendrag
This paper examines the relationship between external relations and innovation in small, knowledge-intensive Norwegian firms. Our findings indicate that external relations are beneficial for innovation. The analysis shows that it is necessary to treat innovation as more than a concept. Our independent variables related differently to product innovation, process innovation, and market innovation. We found that market participation in product development has a positive impact on product, process and market innovation. We also found that top management interaction with other firms had a positive effect on market innovation and that top management interaction with external R&D had a positive effect on product innovation. This finding probably indicates that access to R&D resources is vital for product development in the context of knowledge-intensive products. The results also show that participation in conferences and courses positively influences process and market innovation and that systematic environmental scanning positively influences product innovation.
Forfattere
Subal C. Kumbhakar Gudbrand LienSammendrag
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Sammendrag
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Forfattere
Miklós Tóth Ferenc Szentkirályi József Vuts Agostino Letardi Maria Rosaria Tabilio Gunnhild Jaastad Geir Kjølberg KnudsenSammendrag
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Forfattere
Aksel DøvingSammendrag
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Forfattere
Randi Therese Garmo Adam Dunstan Martin Adam Dunstan Martin Erling Thuen Øystein Havrevoll Håvard Steinshamn Egil Prestløkken Åshild T. Randby Åshild T. Randby Margrete Eknæs Andres Waldmann Olav ReksenSammendrag
Progesterone profiles in Norwegian Red cows were categorized, and associations between the occurrence of irregularities in the profiles and the commencement of luteal activity were investigated. The cows were managed in 3 feeding trials from 1994 to 2001 and from 2005 to 2008 at the Norwegian University of Life Sciences. The cows were followed from calving, and the milk samples collected represented 502 lactations from 302 cows. Milk samples for progesterone analysis were taken 3 times weekly from 1994 throughout 1998 and from 2005 to 2008 and 2 times weekly from 1999 to 2001. Commencement of luteal activity was defined as the first day of 2 consecutive measurements of progesterone concentration >= 3 ng/mL not earlier than 10 d after calving. Delayed ovulation type I was defined as consistently low progesterone concentration, <3 ng/mL for >= 50 d postpartum. Delayed ovulation type II was defined as prolonged interluteal interval with milk progesterone measurements <3 ng/mL for >= 12 d between 2 luteal phases. Persistent corpus luteum (PCL) type I was defined as delayed luteolysis with milk progesterone >= 3 ng/mL for >= 19 d during the first estrous cycle postpartum. Persistent corpus luteum type II was defined as delayed luteolysis with milk progesterone >= 3 ng/mL for >= 19 d during subsequent estrous cycles before first artificial insemination. Delayed ovulation type I was present in 14.7%, delayed ovulation type II in 2.8%, PCL type I in 6.7%, and PCL type II in 3.3% of the profiles. Commencement of luteal activity was related to milk yield, parity, PCL type I, and the summated occurrence of PCL type I and II. The least squares means for the interval to commencement of luteal activity were 24.2 d when PCL type I and II were present and 29.5 d when PCL type I and II were absent. The likelihood of pregnancy to first service was not affected in cows with a history of PCL when artificial insemination was carried out at progesterone concentrations <3 ng/mL (i.e., during estrus); however, cows that had experienced PCL were more likely to be inseminated during a luteal phase. The occurrence of delayed ovulation and PCL in Norwegian Red cows was less than that reported in most other dairy populations.
Sammendrag
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