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.
2016
Forfattere
Rasmus John Normand Frandsen Silas A. Rasmussen Peter B. Knudsen Silvio Uhlig Dirk Petersen Erik Lysøe Charlotte H. Gotfredsen Henriette Giese Thomas O. LarsenSammendrag
Biosynthesis of the black perithecial pigment in the filamentous fungus Fusarium graminearum is dependent on the polyketide synthase PGL1 (oPKS3). A seven-membered PGL1 gene cluster was identified by over-expression of the cluster specific transcription factor pglR. Targeted gene replacement showed that PGL1, pglJ, pglM and pglV were essential for the production of the perithecial pigment. Over-expression of PGL1 resulted in the production of 6-O-demethyl-5-deoxybostrycoidin (1), 5-deoxybostrycoidin (2), and three novel compounds 5-deoxybostrycoidin anthrone (3), 6-O-demethyl-5-deoxybostrycoidin anthrone (4) and purpurfusarin (5). The novel dimeric bostrycoidin purpurfusarin (5) was found to inhibit the growth of Candida albicans with an IC50 of 8.0 +/− 1.9 μM. The results show that Fusarium species with black perithecia have a previously undescribed form of 5-deoxybostrycoidin based melanin in their fruiting bodies.
Sammendrag
Abstract Questions Vegetation mapping based on field surveys is time-consuming and expensive. Distribution modelling might be used to overcome these challenges. What is the performance of distribution modelling of vegetation compared to traditional vegetation mapping when projected locally? Does the modelling performance vary among ecosystems? Does vegetation type distribution and abundance influence the modelling performance? Location Gravfjellet, Øystre Slidre commune, southern Norway. Methods Two comparable neighbouring areas, each of 4 km2, were mapped for species-defined vegetation types. One area was used for model training, the other for model projection. Maximum entropy models were run for six vegetation types, two from each of the ecosystems present in the area: forest, wetland and mountain heath- and shrublands. For each ecosystem, one locally abundant and one locally rare vegetation type were tested. AUC, the area under the receiver operating curve, was used as the model selection criterion. Environmental variables (n = 9) were selected through a backwards selection scheme, and model complexity was kept low. The models were evaluated using independent data. Results Distribution modelling of vegetation types by local projection gave high AUC values, and the results were supported by the evaluation using independent data. The modelling ability was not affected by ecosystem differences. A negative relationship between the number of points used to train the models and the AUC value before evaluation suggests that models for locally rare vegetation types had better predictive performance than the models for abundant types. This result was not significant after evaluation. Conclusion Provided that relevant explanatory variables are available at an appropriate scale, and that field-validated training points are available, distribution modelling can be used for local projection of the six tested vegetation types from the boreal–alpine ecotone.
Forfattere
Louise C. Ross Gunnar Austrheim Leif Jarle Asheim Gunnar Bjarnason Jon Feilberg Anna Maria Fosaa Alison J. Hester Øystein Holand Ingibjörg S Jónsdóttir Lis E. Mortensen Atle Mysterud Erla Olsen Anders Skonhoft James David Mervyn Speed Geir Steinheim Des B.A. Thompson Anna G. ThorhallsdottirSammendrag
Sheep grazing is an important part of agriculture in the North Atlantic region, defined here as the Faroe Islands, Greenland, Iceland, Norway and Scotland. This process has played a key role in shaping the landscape and biodiversity of the region, sometimes with major environmental consequences, and has also been instrumental in the development of its rural economy and culture. In this review, we present results of the first interdisciplinary study taking a long-term perspective on sheep management, resource economy and the ecological impacts of sheep grazing, showing that sustainability boundaries are most likely to be exceeded in fragile environments where financial support is linked to the number of sheep produced. The sustainability of sheep grazing can be enhanced by a management regime that promotes grazing densities appropriate to the site and supported by area-based subsidy systems, thus minimizing environmental degradation, encouraging biodiversity and preserving the integrity of ecosystem processes.
Forfattere
Erik Lysøe Rasmus J.N. Frandsen Hege Divon Valeria Terzi Luigi Orrù Antonella Lamontanara Anna-Karin Kolseth Kristian F. Nielsen Ulf ThraneSammendrag
Fusarium langsethiae is a widespread pathogen of small grain cereals, causing problems with T-2 and HT-2 toxin contamination in grains every year. In an effort to better understand the biology of this fungus, we present a draft genome sequence of F. langsethiae Fl201059 isolated from oats in Norway. The assembly was fragmented, but reveals a genome of approximately 37.5 Mb, with a GC content around 48%, and 12,232 predicted protein-coding genes. Focusing on secondary metabolism we identified candidate genes for 12 polyketide synthases, 13 non-ribosomal peptide synthetases, and 22 genes for terpene/isoprenoid biosynthesis. Some of these were found to be unique compared to sequence databases. The identified putative Tri5 cluster was highly syntenic to the cluster reported in F. sporotrichioides. Fusarium langsethiae Fl201059 produces a high number of secondary metabolites on Yeast Extract Sucrose (YES) agar medium, dominated by type A trichothecenes. Interestingly we found production of glucosylated HT-2 toxin (Glu-HT-2), previously suggested to be formed by the host plant and not by the fungus itself. In greenhouse inoculations of F. langsethiae Fl201059 on barley and oats, we detected the type A trichothecenes: neosolaniol, HT-2 toxin, T-2 toxin, Glu-HT-2 and numerous derivatives of these.
Forfattere
Mogens Lund Jørgen Dejgård JensenSammendrag
The aim of the article is to identify and analyse public-private incentives for the development and marketing of new animal vaccines within a real options methodological framework, and to investigate how real options methodology can be utilized to support economic incentives for vaccine development in a cost-effective way. The development of a vaccine against Campylobacter jejuni in poultry is applied as a case study. Employing the real options methodology, the net present value of the vaccine R&D project becomes larger than a purely probabilistic expected present value throughout the different stages of the project − and the net present value becomes larger, when more types of real options are taken into consideration. The insight from the real options analysis reveals opportunities for new policies to promote the development of animal vaccines. One such approach might be to develop schemes combining stage-by-stage optimized subsidies in the individual development stages, with proper account taken of investors’/developers' economic incentives to proceed, sell or cancel the project in the respective stages. Another way of using the real options approach to support the development of desirable animal vaccines could be to issue put options for the vaccine candidate, enabling vaccine developers to hedge against the economic risk from market volatility.
Sammendrag
Herbivory by insects and mites on physic nut (Jatropha curcas L.) seedlings was investigated and compared with irrigation in the semi-arid Sahelian Niger, utilizing a randomized complete block design experiment. Three water treatment protocols were applied and the types of damage were recorded. Less than 5% of the seedlings died during the 10-month trial period with sap suckers causing the most damage on the surviving plants. Plants with high production of biomass and leaf cover (foliage) were most strongly positively correlated with irrigation and were also the plants that endured the highest degree of herbivory. The low dieback may indicate that defence mechanisms counteract seedling herbivory and that drought-stressed plants invest more in their defence mechanism system than vital plants.
Forfattere
Yanliang Wang Tore Krogstad Jihong Liu Clarke Moritz Hallama Anne K. Falk Øgaard Susanne Eich-Greatorex Ellen Kandeler Nicholas ClarkeSammendrag
Det er ikke registrert sammendrag
Forfattere
Irene Biancarosa Marit Espe Christian Guido Bruckner Svenja Heesch Nina Sylvia Liland Rune Waagbø Bente Elisabeth Torstensen Erik-Jan LockSammendrag
The Norwegian seaweed industry is expanding and there is a need for accurate estimates of protein content of seaweed species from Norwegian waters. A solid method to calculate protein content is through the sum of the proteomic amino acids; however, it can be expensive and beyond the capacities of many laboratories. The most commonly used method to quantify protein is based on the assessment of crude protein from overall nitrogen content, using the traditional nitrogen-to-protein conversion factor of 6.25. However, this approach can be inaccurate when applied to seaweeds, often resulting in an overestimation of their protein content. Specific nitrogen-to-protein conversion factors, calculated from amino acid composition and total nitrogen, give a more reliable protein quantification in seaweeds. However, no such factors are available for species from Norwegian waters. This study was designed to characterize the amino acid composition of 21 seaweed species from Norwegian waters and use the amino acid data to estimate protein contents of the seaweeds. Crude protein analysis (nitrogen × 6.25) was performed and resulted in overestimation (18–44 %) of the protein content compared to the sum of proteomic amino acids. Specific nitrogen-to-protein conversion factors, calculated for each species, ranged from 3.53 ± 0.1 to 5.13 ± 0.1. This study provides nutritional data on Norwegian seaweeds, covering a relatively wide range of species. Moreover, it is the first study to assess nitrogen-to-protein conversion factors on such species.
Forfattere
Hadush Tsehaye Beyene Abdelhameed Elameen Anne Marte Tronsmo Leif Sundheim Arne Tronsmo Dereje Assefa May Bente BrurbergSammendrag
Amplified fragment length polymorphism (AFLP) was used to study the genetic variation among 80 F. verticillioides isolates from kernels of Ethiopian maize, collected from 20 different maize growing areas in four geographic regions. A total of 213 polymorphic fragments were obtained using six EcoRI/MseI primer combinations. Analysis of the data based on all 213 polymorphic AFLP fragments revealed high level of genetic variation in the F. verticillioides entities in Ethiopia. About 58% of the fragments generated were polymorphic. The genetic similarity among F. verticillioides isolates varied from 46% to 94% with a mean Dice similarity of 73%. Unweighted Pair Group Method with Arithmetic Average (UPGMA) analysis revealed two main groups and four subgroups. The principal coordinate analysis (PCO) also displayed two main groups that agreed with the results of UPGMA analysis, and there was no clear pattern of clustering of isolates according to geographic origin. Analysis of molecular variance: (AMOVA) showed that only 1.5% of the total genetic variation was between geographic regions, while 98.5% was among isolates from the same geographic regions of Ethiopia. Eighty distinct haplotypes were recognized among the 80 isolates analyzed. Hence, breeding efforts should concentrate on quantitative resistance that is effective against all genotypes of the pathogen.
Forfattere
Eivind Vangdal Alena Gibalova Jorunn Børve Iren Knutsen Mojca Korošec Rajko Vidrih Per Gustav Anders LeufvénSammendrag
Aroma is an important quality factor in fruit, and it is important to know the effect of new orchard management practices on fruit aroma. Fruit growers are using more foliar fertilizers to achieve the optimum mineral status in fruit. In this work the effects of adding extra nitrogen, calcium and both nitrogen and calcium to apple trees in the fruit cell division phase were studied. Even though the given nitrogen and calcium did not give significantly higher content of N and Ca in the treated fruits, differences in the contents of some aroma compounds were found. Nitrogen treated trees gave apples with more hexanal, a compound known in unripe ("green, grassy") apples. When both calcium and nitrogen were applied, the negative effect of nitrogen on aroma compounds was less pronounced. The aroma of these fruits was more similar to the controls. Using multivariate statistical analyses, the grouping of the different treatments during storage was confirmed. Foliar fertilization with nitrogen and calcium during the cell division phase had a significant effect on the amount of aroma compounds in apples at harvest and during storage.