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.
2008
Sammendrag
We deleted the FgStuA gene in Fusarium graminearum and demonstrate its involvement in spore development, pathogenicity and secondary metabolism. The FgStuA protein is a member of the APSES family which regulate morphogenesis and virulence in ascomycetes. FgStuA is closely related to FoStuA in F. oxysporum and stuA in Aspergillus, but unlike FoStuA mutants, the FgStuA mutants were greatly reduced in pathogenicity on wheat and colonization of apple slices. The mutant produces no detectable trichothecenes on the wheat cultivar Bobwhite, and
Sammendrag
The filamentous fungus Fusarium graminearum causes extensive losses on cereals world-wide and contaminates harvested grain with mycotoxins, whose levels in the food supply are strictly regulated. We deleted the FgStuA gene in Fusarium graminearum and demonstrate its involvement in several different processes, such as spore development, pathogenicity and secondary metabolism. The FgStuA protein is a members of the APSES family which regulate morphogenesis and virulence in ascomycetes. FgStuA is closely related to FoStuA in F. oxysporum and StuA in Aspergillus, but unlike FoStuA mutants, the FgStuA mutants were greatly reduced in pathogenicity both on wheat and apple slices. Reduced pathogenicity may be due to decreased levels of trichothecene mycotoxins (
Forfattere
Håvard SteinshamnSammendrag
Grassland legumes are essential in organic ruminant livestock production due to their ability to fix atmospheric nitrogen (N), providing high yields of high feeding value without N fertilization. White clover (Trifolium repens L.) and red clover (Trifolium pratense L.) are the most important legumes of temperate grasslands with white clover as the most widely used. New research has reviled new properties of red clover that may affect animal performance and product quality significantly. Red clover containing diets have increased the production of milk and meat (compared with grasses) and the content of beneficial fatty acids in milk and meat (compared with grasses and other legumes), improved the efficiency of feed N utilization (compared with Medicago sativa L.), and increased the milk content of isoflavones (compared with grass and white clover). Red clover contains high levels of the enzyme polyphenol oxidase that might reduce the extent of lipolysis and proteolysis. The paper presents a review on resent results from own and others" research on the use of red clover in the diet of ruminants and the likely mechanisms by which red clover affects production and product quality
Sammendrag
A major challenge in studies on the environmental fate of nanoparticles is to detect their presence and distinguish them from natural nanoparticles and the large variety of amorphous materials present in environmental media. Neutron activation of mineral particles enables the production of radio-labelled NPs without surface modification, and enabling both localisation and quantification within a matrix or organism. The method is extremely sensitive, allowing detection at parts per billion or lower. Thus, any such labelled NP can be detected in individual fractions or compartments in soil or sediments (associated to clay, colloids, humic material, etc) or localized within organisms and their specific tissues following dissection (fish gills, digestive tract, liver, brain, etc) or by autoradiography. An added advantage of gamma-emitting radionuclides is that they do not need separation from the matrix for counting, thus uptake and extraction can be followed on live animals. Thus time-course experiments in vivo may be conducted to study metabolism and exposure, two aspects that are currently lacking in the body of ecotoxicological knowledge about ENPs. This paper will report some of the conditions, advantages and experimental opportunities of using neutron activation as a tool to study ENPs in environmental samples, with demonstration of the application of the technique in studies on Ag and Co nanoparticle uptake and metabolism in the earthworm Eisenia fetida.
Forfattere
Espen Govasmark Brit SalbuSammendrag
Det er ikke registrert sammendrag
Forfattere
Espen Govasmark Brit SalbuSammendrag
Det er ikke registrert sammendrag
Forfattere
Espen GovasmarkSammendrag
Det er ikke registrert sammendrag
Sammendrag
A characterisation of the hydrological behaviour of four small agricultural catchments in Estonia and Norway was carried out using a flashiness index (FI). FI reflects the frequency and rapidity of short term changes in runoff values. A comparison of FIs based on hourly and average daily discharge indicated large within-day variations over very short time intervals. Large differences were observed between the Norwegian and Estonian catchments, irrespective of whether average daily discharge or hourly discharge values were used. A comparison of the FI and the base flow index (BFI) showed that high FI values corresponded to low BFI values. Norwegian catchments with high FI or low BFI values showed high nutrient losses, whereas the contrary was observed for the Estonian catchments. Although the FI does not a priori give information about the flow processes within catchments, we believe that the FI, as well as the BFI, might be helpful in explaining differences in nutrient and soil losses between catchments.
Forfattere
Peder Gjerdrum Anna BarszczSammendrag
The present research concerned selected characteristics of knottiness of large-dimensioned spruce timber (of trees with the minimum breast-height diameter of 40 cm over bark) from three stands, over one hundred years old, located in south-eastern Norway. Fourteen sample trees were felled and measured, and knots which occurred in them were classified into three categories of healthiness and three categories of tightness with the surrounding wood. Sound and tight knots were dominant in the timber under analysis. All categories varied significantly in relation to average diameters, relative diameters (related to stem thickness at the points where the knots occurred) and the relative height of location along merchantable boles. The researches analysed the significance of relations of diameters or relative diameters of knots with the relative height of their location along merchantable boles...
Forfattere
Petter Nilsen Line Tau StrandSammendrag
The present paper deals with C and N storage in soil and vegetation, litter fall and CO2 efflux from the soil 32-33 years after early thinning in a Norway spruce (Picea abies (L.) Karst.) stand in order to evaluate the effect of thinning regime on C sequestration. At 22 years old, the stand was reduced from 3190 to 2070, 1100 and 820 trees per hectare in four replicates. The N2070 treatment represents the recommended start density in practical forestry, while the other represent a moderate to large reduction in tree number at the present stand age. Aboveground biomass was estimated from single tree measurements of diameter and height based on allometric functions. Litter fall was collected during one and a half years and soil respiration was measured on five occasions during one summer. Ground vegetation was mapped and sampled for biomass, C and N determination. A significant decrease in aboveground tree (including stump-root system) C storage of 27% and 22% due to thinning was found in the N820 and N1100 treatments, respectively, compared to the N2070 treatment. Ground vegetation C storage was little affected by treatment, while litter fall C showed a non-significant decrease in the N820 and N1100 treatments compared to the N2070 treatment. Soil respiration was significantly lower in parts of the summer in the N2070 treatment compared to the N820 treatment. The reason for this is still unexplained since no differences in soil temperature, soil moisture or litter fall chemistry was found between the treatments. No significant treatment effects on humus and mineral soil C storage could be detected. With the present soil variability, the time period of 32 years is probably too short to detect soil C differences due to thinning. The N storage followed the same pattern as for C. (C) 2008 Elsevier B.V. All rights reserved.