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.
2011
Forfattere
jihong liu clarke Even Sannes Riiser Ingrid Holtsmark Sonja Klemsdal Sadhu Leelavathi Andreas Lössl Vanga S. Reddy Nagothu U. Sekhar Hege Særvold Steen Sathyamangalam Swaminathan Rebekka ØvstegårdSammendrag
Dengue viruses (Flavivirus) are mosquito-borne human pathogens with a worldwide prevalence. There are four antigenically-related dengue virus serotypes, DEN-1 to DEN-4, which cause serious problems of morbidity and mortality. Dengue is emerging rapidly as one of the most important public health problems in countries of the Asia-Pacific region with nearly 1.8 billion people in the region at risk, compared to an estimated total of 2.5 billion globally (WHO 2009). The disease has resulted in widespread social and economic problems, especially among the poor, who are the most vulnerable group. There is currently no vaccine to prevent dengue virus infection making it difficult to control and manage the disease, although considerable efforts have been made, including vector control, sanctions, law enforcement and public education (www.who.int). A DEN vaccine must be tetravalent, as immunity to a single serotype does not offer cross-protection against the other serotypes the yeast Pichia pastoris. In this study, we aim to develop a similar envelope domain III (EDIII)-based chimeric antigen which elicits neutralizing antibodies against all four DEN serotypes. The antigen will be expressed in tobacco chloroplasts, aiming for a cost-effective and safe production system by joint efforts of Indo-Norwegian bilateral collaboration.
Forfattere
Sigbjørn Stokke Silje Vang Jon Martin Arnemo Magnus Hansson Ole Roer Asle Stokkereit Erling L. Meisingset Børge Wahl Ingmar Slettemark Bjørnar Asmund Johnsen Gundula Bartzke Christer Moe Rolandsen Erling Johan SolbergSammendrag
Norge har lange tradisjoner for å utøve jakt og fiske, og det er fokus på at dette skal skje innen etisk forsvarlige rammer. I de siste 25 årene har spesielt hjorteviltet blitt en viktigere jaktressurs og i takt med dette har kravene til jaktutøvelse blitt skjerpet. I dag kreves det aktiv opplæring av nye jegere, samt en årlig skytetrening med innlagte tester for storviltjegere. I tillegg er hunden blitt en viktigere faktor, både for å drive fram viltet og for å finne eventuelle skadde dyr. Det stilles nå krav til at en godkjent ettersøkshund er tilgjengelig ved jakt på både elg, hjort og rådyr. Disse hundene skal ha bestått en ferskspor- og en blodsporprøve for å bli godkjent. Imidlertid foregår det ingen testing av ettersøkshundenes evne til å følge ett og samme dyr, noe som er påkrevet dersom intensjonen med kravet om ettersøkshund skal oppfylles. Det har nylig blitt vist at ettersøkshunder som sporet bjørn i liten grad evnet å følge den bjørnen de var satt til å spore. Direktoratet for naturforvaltning (DN) nedsatte derfor i 2010 en kontaktgruppe bestående av representanter fra DN, Norges Jeger- og Fiskerforbund samt Norsk Kennel Klub i den hensikt å evaluere den nåværende ordningen med opplæring og godkjenning av ettersøkshunder. Gruppas mandat var å gå gjennom gjeldende forskrift og instruks, samt å fremme forslag om nødvendige endringer basert på nyervervet kunnskap. Gruppa ønsket spesifikt å se på hvorvidt hunder som var godkjent etter ulike godkjenningsordninger fungerte etter hensikten. Norsk institutt for naturforskning (NINA) ble i den sammenheng forespurt om å gjennomføre evalueringen. For å evaluere hvorvidt en ettersøkshund evner å følge et spesifikt hjorteviltindivid, valgte vi å teste ettersøksekvipasjer (hund og fører) i forhold til GPS-merkede individer av elg og hjort. Til dette fikk vi disponere 13 GPS-radiomerkede elger som Faun Naturforvaltning administrerer i Gardermoenområdet, samt 5 GPS-radiomerkede hjorter fra Hordahjortprosjektet. Senderne ble så reprogrammert til å registrere dyrenes posisjoner hvert 5. minutt. I forkant av testene ble elgene eller hjortene oppsøkt og skremt av en person, hvorpå dyreindividets siste posisjon før skremming ble merket, og den umiddelbare fluktretningen ble registrert. Hvert av ettersøksdyrene ble observert direkte for å forsikre oss om at ingen medfølgende, umerka individer skulle kunne villede hunden. Ettersøksekvipasjen ble siden satt til å spore dyret etter en tidsforsinkelse på 2-22 timer, og fikk anledning til å holde på i en time før ettersøket ble avsluttet. I likhet med ettersøksdyrene ble sporruta til ettersøksekvipasjene registrert ved bruk av en GPS. Vi evaluerte så ekvipasjenes sporingsevne ved å sammenligne sporruta til ettersøksekvipasjen med sporruta til ettersøksdyret. NØKKELORD Norge, Akershus, Gardermoen, Hordaland, ettersøk, ettersøkshund, id-sporing, fersksporprøve, blodsporprøve, elg, hjort, GPS, GIS, radiomerking, modellering, skadeskyting KEY WORDS : Norway, Akershus, Gardermoen, Hordaland, tracking down wounded animals, dog used to track down wounded animals, idtracking, trials on fresh tracks, trials on blood-tracks, moose, red deer, GPS, GIS, radio-collaring, modelling, wounding
Sammendrag
We used two datasets of 14C analyses of archived soil samples to study carbon turnover in O horizons from spruce dominated old-growth stands on well-drained podsols in Scandinavia. The main data set was obtained from archived samples from the National Forest Soil Inventory in Sweden and represents a climatic gradient in temperature. Composite samples from 1966, 1972, 1983 and 2000 from four different regions in a latitude gradient ranging from 57 to 67oN were analysed for 14C content. Along this gradient the C stock in the O horizon ranges from 2.1 kg m-2 in the north to 3.7 kg m-2 in the southwest. The other data set contains 14C analyses from 1986, 1987, 1991, 1996 and 2004 from the O horizons in Birkenes, Norway. Mean residence times (MRT) were calculated using a two compartment model, with a litter decomposition compartment using mass loss data from the literature for the three first years of decomposition and a humus decomposition compartment with a fitted constant turnover rate. We hypothesized that the climatic gradient would result in different C turnover in different parts of the country between northern and southern Sweden. The use of archived soil samples was very valuable for constraining the MRT calculations, which showed that there were differences between the regions. Longest MRT was found in the northernmost region (41 years), with decreasing residence times through the middle (36 years) and central Sweden (28 years), then again increasing in the southwestern region (40 years). The size of the soil organic carbon (SOC) pool in the O horizon was mainly related to differences in litter input and to a lesser degree to MRT. Because N deposition leads both to larger litter input and to longer MRT, we suggest that N deposition contributes significantly to the latitudinal SOC gradient in Scandinavia, with approximately twice as much SOC in the O horizon in the south compared to the north. The data from Birkenes was in good agreement with the Swedish dataset with MRT estimated to 34 years.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Gene expression levels (PAL, CCR1, HCT1, and CAD for the phenylpropanoid pathway, PX3 peroxidase, and CHI4 class IV chitinase), lignin, and soluble and cell wall bound phenolic compounds in bark and sapwood of Picea sitchensis clones inoculated with Heterobasidion annosum s.s. were compared before and 3 days after wounding and artificial inoculation, at site of inoculation and 1 cm above the inoculation site. In bark all genes were up-regulated at the site of inoculation but, except for CAD, not in the distal zone. In sapwood all genes were down-regulated, except for PX3 and CHI4; PAL, CCR1, HCT1 and CAD were present at lower levels around the inoculation site than in the distal zone. Compared to wounding only, inoculation with H. annosum triggered different CAD, PX3, and CHI4 levels in bark but not in sapwood. Different concentrations of cell wall bound phenolic compounds (unknown2, unknown3, coniferin, astringin, taxifolin, piceid, and isorhapontin) were found in bark after wounding and inoculation compared to constitutive material (i.e. untreated samples), whereas in sapwood concentrations did not differ following treatment. These results indicate that bark of Sitka spruce has a stronger and earlier response to wounding and pathogen inoculation than sapwood.
Forfattere
Tao Zhao Paal Krokene Jiang Hu Erik Christiansen Niklas Björklund Bo Långström Halvor Solheim Anna-Karin Borg-KarlsonSammendrag
Background: Tree-killing bark beetles (Coleoptera, Scolytinae) are among the most economically and ecologically important forest pests in the northern hemisphere. Induction of terpenoid-based oleoresin has long been considered important in conifer defense against bark beetles, but it has been difficult to demonstrate a direct correlation between terpene levels and resistance to bark beetle colonization. Methods: To test for inhibitory effects of induced terpenes on colonization by the spruce bark beetle Ips typographus (L.) we inoculated 20 mature Norway spruce Picea abies (L.) Karsten trees with a virulent fungus associated with the beetle, Ceratocystis polonica (Siem.) C. Moreau, and investigated induced terpene levels and beetle colonization in the bark. Results: Fungal inoculation induced very strong and highly variable terpene accumulation 35 days after inoculation. Trees with high induced terpene levels (n = 7) had only 4.9% as many beetle attacks (5.1 vs. 103.5 attacks m22) and 2.6% as much gallery length (0.029 m m22 vs. 1.11 m m22) as trees with low terpene levels (n = 6). There was a highly significant rank correlation between terpene levels at day 35 and beetle colonization in individual trees. The relationship between induced terpene levels and beetle colonization was not linear but thresholded: above a low threshold concentration of ,100 mg terpene g21 dry phloem trees suffered only moderate beetle colonization, and above a high threshold of ,200 mg terpene g21 dry phloem trees were virtually unattacked. Conclusion/Significance: This is the first study demonstrating a dose-dependent relationship between induced terpenes and tree resistance to bark beetle colonization under field conditions, indicating that terpene induction may be instrumental in tree resistance. This knowledge could be useful for developing management strategies that decrease the impact of tree-killing bark beetles.
Forfattere
Axel Schmidt Raimund Nagel Trygve Krekling Erik Christiansen Jonathan Gershenzon Paal KrokeneSammendrag
Norway spruce (Picea abies) defends itself against herbivores and pathogens by formation of traumatic resin ducts filled with terpenoid-based oleoresin. An important group of enzymes in terpenoid biosynthesis are the short-chain isoprenyl diphosphate synthases which produce geranyl diphosphate (C10), farnesyl diphosphate (C15), and geranylgeranyl diphosphate (C20) as precursors of monoterpenes, sesquiterpenes, and diterpene resin acids, respectively. After treatment with methyl jasmonate (MJ) we investigated the expression of all isoprenyl diphosphate synthase genes characterized to date from Norway spruce and correlated this with formation of traumatic resin ducts and terpene accumulation. Formation of traumatic resin ducts correlated with higher amounts of monoterpenes, sesquiterpenes and diterpene resin acids and an upregulation of isoprenyl diphosphate synthase genes producing geranyl diphosphate or geranylgeranyl diphosphate. Among defense hormones, jasmonate and jasmonate-isoleucine conjugate accumulated to higher levels in trees with extensive traumatic resin duct formation, whereas salicylate did not. Jasmonate and ethylene are likely to both be involved in formation of traumatic resin ducts based on elevated transcripts of genes encoding lipoxygenase and 1-aminocyclopropane-1-carboxylic acid oxidase associated with resin duct formation. Other genes involved in defense signalling in other systems, mitogen-activated protein kinase3 and nonexpressor of pathogenesis-related gene1, were also associated with traumatic resin duct formation. These responses were detected not only at the site of MJ treatment, but also systemically up to 60 cm above the site of treatment on the trunk.
Sammendrag
The species composition of wood-inhabiting fungi (polypores and corticoids) was investigated on 1138 spruce logs and 992 pine logs in 90 managed and 34 natural or near-natural spruce and pine forests in SE Norway. Altogether, the study included 290 species of wood-inhabiting fungi. Comparisons of logs with similar properties (standardized tree species, decay class, dimension class) in natural and managed forests showed a significant reduction in species number per log in managed spruce forests, but not in managed pine forests. The species number per log in managed spruce forests was 10–55% lower than on logs from natural spruce forests. The reduction was strongest on logs of large dimensions. A comparison of 200–400 spruce logs from natural and managed forests showed a 25% reduction in species richness corresponding to a conservative loss of ca. 40 species on a regional scale. A closer inspection revealed that species confined to medium and very decayed spruce logs were disfavored in managed forests, whereas species on early decay classes and decay generalists were unaffected. Similarly, species preferring large spruce logs were disfavored in managed forests. Forest management had strongest impact on low-frequent species in the spruce forests (more than 50% reduction), whereas common species were modestly affected. Corticoid fungi were more adversely affected than polypore fungi. These results indicate that wood-decaying fungi in pine forests are more adapted to forest disturbances than spruce-associated species. Management measures securing a continuous supply of dead wood are more important in spruce forests than in pine forests.
Forfattere
Stine Gregersen Vhile Nils Petter Kjos Aud Kari Fauske Henning Sørum Randi Seljåsen Margareth ØverlandSammendrag
Det er ikke registrert sammendrag
Forfattere
Christer MagnussonSammendrag
Nematodes, commonly known as round worms, are the most common multicellular animals on planet Earth. After 1000 million years of evolution members of the phylum Nematoda have a high bionomic diversity. As habitants of the soil and rhizosphere nematodes are involved en energy fluxes, and affect carbon and nutrient cycles. As plant parasites, either alone or in synergism with other pathogens, nematodes are responsible for plant disease complexes and major crop losses. A growth depression in a field of potato (Solanum tuberosum) cv. Saturna [resistant to pathotype Ro1 of potato cyst nematode (PCN) Globodera rostochiensis], suggestive of potato cyst nematode damage, was detected in Grue, eastern Norway. Analyses of soil samples did not detect PCN, but demonstrated the occurrence of a large number of lesion nematodes Pratylenchus penetrans .Tubers from the depressed part of the field had severe symptoms similar to those caused by the common scab bacterium Streptomyces scabies. Potato yield was reduced by 50% in the affected area of the field. Transect-sampling showed plant growth to be negatively correlated with densities of P. penetrans and suggested a damage threshold of potato to the nematode of 100 specimens per250 g of soil. Common scab (Streptomyces scabies) occurred frequently in the affected area. P. penetrans was present in roots, underground stems, stolons and tubers. Tubers from the depressed part of the field had severe symptoms similar to those caused by the common scab bacterium. In tubers, nematodes were detected inside cross-lesions typical symptoms of common scab, and occurred also in the outermost 0.5 mm tissue associated with such lesions. In pots with sterile sand, micro-tubers of potato cv. Saturna, produced from meristems, were grown in a green-house infected with, P. penetrans, S. scabies, and a combination of P. penetrans and, S. scabies. P. penetrans alone induced tuber lesions similar to those of common scab. Also, the combined inoculation of the bacterium and the nematode seemed to enhance symptom expression. Similar scab symptoms, in connection with lesion nematode infections, have been observed on potato tubers cv. Oleva, which also is relatively tolerant to common scab. Symptomatic tubers cv. Saturna first stored at 4o C for 20 weeks were transferred to pots with sterile sand and grown for 3 months in the green-house. In these cultures P. penetrans was first detected in soil 8 weeks after planting. Examination at harvest of soil, roots, stolons, tubers demonstrated symptoms typical of P. penetrans. Interestingly, P. penetrans survives storage of potatoes, from which new infections may develop. Hence, potato tubers do appear to be an important means for the spread of P. penetrans to new areas. The fact that the symptoms induced by this nematode may be mistaken for symptoms of common scab suggests that the frequency of S. scabies might have been overestimated in regular surveys. Infections by P. penetrans have important implications for scab control. This pertains in particular to recommended maintenance of high soil moisture at and during 4-9 weeks after tuber set. If symptoms are related to nematode infection rather than to the scab bacterium, this recommendation would allow for a rapid build-up of lesion nematodes resulting in a decrease in both yield and marketability of the tubers. Further studies are needed to investigate the extent of this problem.