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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.

2008

Sammendrag

Objective To develop a tetravalent dengue antigen and to express and evaluate the antigen in tobacco chloroplasts, aiming for a cost-effective and safe production system. Methodology EDIII-encoding sequences corresponding to all four DEN virus serotypes were fused, generating a tetravalent gene, rEDIII-T, and integrated into the Pichia pastoris genome. A 6xHis Tag-encoding sequence was designed at the 3" end. The recombinant EDIII-T protein was expressed and purified. Balb/c mice (4-6 weeks old) were immunized intraperitoneally on days 0, 21, 42 and 84 with 20 "g purified rEDIII-T protein. Immune sera from the immunized mice were used to detect the DEN virus serotypes in infected BHK 21 cells. A plaque reduction neutralization test was performed using each DEN virus serotype pre-incubated with heat-inactivated serum, plaqued on LLCMK2 cells with 50 "l virus-antiserum mix/well. Results A novel tetravalent chimeric protein was developed by fusing the receptor-binding envelope domain III (EDIII) of the four DEN virus serotypes. This protein was expressed in the yeast Pichia pastoris and purified to near homogeneity in high yields. Antibodies induced in mice by the tetravalent protein, formulated in different adjuvants, neutralized the infectivity of all four serotypes. Conclusions and future work We developed a non-replicating subunit vaccine prototype based on EDIII, a critical domain of the major DEN virus E protein that mediates viral entry, contains multiple neutralizing epitopes and induces robust protective immunity. The EDIII-based recombinant protein is a promising candidate for the development of a safe, efficacious, and inexpensive tetravalent DEN vaccine. Our goal is to express and evaluate the antigen in tobacco chloroplasts aiming for a cost-effective and safe production system.

Sammendrag

This paper describes a stochastic linear programming model for farms with a milk and cattle meat production system. This model documentation is worked out using the farm account records for three family farms in Northern Norway. The model is built in Excel using the addin Simetar to analyze risks. The LP model maximizes farm gross margins but the fixed costs of each farm are subtracted in order to compute farm profit and risk in farm profit. Data for the 15 years from 1991–2005 from the farms and from the annual editions of the Handbook of farm planning (NILF, 2000) have been used as a basis for developing the stochastic variables. The following variables have been made stochastic: area and yield of green fodder, yields of leys and pastures, yield of milk per cow, meat price, milk price, fuel costs and costs of concentrate feed. The rate of interest is also made stochastic. In the model the rate of interest is affecting the risk in farm profit through the fixed costs. Emphasize has been given to build a flexible model allowing for examining effects of changes in several ways e.g. length of grazing period, calving time, or harvesting method for grass. The milk production is restricted by a farm specific milk quota, but otherwise the farming intensity is varied as farmers may choose selling e.g. small calves or up to two years old castrates with extensive use of pasture. Updating the model with data for another year is facilitated by defining prices for one year at a time and by cell referencing all variables. The records may be replaced with records for family farms with similar production systems in other areas in the country. The production is based on grass and pasture roughage. Dairy farms in more central areas also produce cereals, grain and oilseeds and the model has to be developed further for such farms. The model will be used to carry out different farm economics analysis for Norwegian family farms combining milk and cattle meat production in production systems involving extensive use of pasture.

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Sammendrag

Sweet potato (Ipomoea batatas L.) is the fifth most important crop in the developing countries after rice, wheat, maize and cassava. The amplified fragment length polymorphism (AFLP) method was used to study the genetic diversity and relationships of sweet potato accessions in the germplasm collection of Sokoine University of Agriculture, Morogoro and Sugarcane Research Institute, Kibaha, Tanzania. AFLP analysis of 97 sweet potato accessions using ten primer combinations gave a total of 202 clear polymorphic bands. Each one of the 97 sweet potato accessions could be distinguished based on these primer combinations. Estimates of genetic similarities were obtained by the Dice coefficient, and a final dendrogram was constructed with the un-weight pair-group method using arithmetic average. AFLP-based genetic similarity varied from 0.388 to 0.941, with a mean of 0.709. Cluster analysis using genetic similarity divided the accessions into two main groups suggesting that there are genetic relationships among the accessions. Principal Coordinate analysis confirmed the pattern of the cluster analysis. Analysis of molecular variance revealed greater variation within regions (96.19%) than among regions (3.81%). The results from the AFLP analysis revealed a relatively low genetic diversity among the germplasm accessions and the genetic distances between regions were low. A maximally diverse subset of 13 accessions capturing 97% of the molecular markers diversity was identified. We were able to detect duplicates accessions in the germplasm collection using the highly polymorphic markers obtained by AFLP, which were found to be an efficient tool to characterize the genetic diversity and relationships of sweet potato accessions in the germplasm collection in Tanzania.

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Sammendrag

A sample selection framework that simultaneously takes into account the two-step decision-making of forest owners (first whether or not to harvest, second the level of harvesting) is applied on representative cross-sectional data for forest properties and owners in Norway. Forest management plans, property size, forested area and income from agriculture are found to increase both the propensity to harvest and the harvesting levels. Income from engagement in other outfield-related productions and debt burden increase the propensity to harvest only, while increased age impact negatively on the harvesting decision. Wage income affects both propensities to harvest and harvesting levels negatively. The results suggest that other on-property productions may stimulate harvesting decisions, while off-property income impact harvesting decisions and levels negatively. (C) 2007 Elsevier GmbH. All rights reserved.

Sammendrag

Livestock farming is an important part of organic farming systems, and it is an explicit goal of organic farming to ensure high levels of animal health and welfare (AHW) through proactive and appropriate management of breeding, feeding, housing and species specific husbandry. A goal in organic livestock farming is to minimise the use of veterinary medicines to improve food quality and protect the environment, and to do this by improving livestock living conditions rather than using alternative medical treatments. Key values influencing organic livestock production are naturalness, harmony at all levels of production, use and recirculation of local resources and adoption of the precautionary principle. The concepts of "positive health and welfare" are incorporated in EU Regulation 2092/91 on organic production. The farmer must ensure that farm animals can perform natural behaviours and live natural lives, but at the same time he/she must intervene when necessary and at first signs of disharmony in the herd. Based on various project experiences and results and research questions from different European countries, a research project entitled `Minimising medicine use in organic dairy herds through animal health and welfare planning" was initiated in mid-2007 with the aim as indicated in the title. This paper introduces the project. The first project meeting and workshop was held in Hellevad in Denmark on the 9th-12th October 2007. A summary of the outputs from the workshop is provided here. The anticipated project activities are also outlined. The project will adopt the name ANIPLAN.

Sammendrag

Bitterrote på søtkirsebær er rapportert frå Sveits, Ungarn og Norge. Det er lite publisert kunnskap om sjukdomen på søtkirsebær. Artikkelen gjev eit oversyn over arbeid gjort i Noreg.

Sammendrag

New restrictions draw governments, industry and research towards new and environmental benign wood protective agents. These agents often come from a natural source, and are also a waste product. One of these is chitosan. Chitosan is a derivative from chitin, mainly found in the exoskeleton of crustacean. Some research has been conducted on chitosan and wood. Chitosan has earlier proven good antifungal effectiveness, but to achieve a good protection, a 5 % concentration is needed, which makes the end product quite expensive. In recent research, a way to make chitosan treated wood hydrophobic has been invented. The objective of the research presented in this paper, is to describe the effectiveness of the following compounds: Chitosan, chitosan/copper, chitosan/boron and chitosan/Scanimp (a commercial wood preservative). Results show that chitosan works well alone, but has a fixation problem. Chitosan and boron give good fixation, and reduced amounts of chitosan and together give good protection against wood destroying fungi. The fire protection agents are promising, but needs higher concentration and/or better fixation to give a sufficient protection against wood destroying fungi