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.
2020
Forfattere
Rui Xia Yalin Yang Xingliang Pan Chenchen Gao Yuanyuan Yao Xuewei Liu Tsegay Teame Fengli Zhang Juan Hu Chao Ran Zhen Zhang Jihong Liu Clarke Zhigang ZhouSammendrag
Quorum quenching (QQ) blocks bacterial cell-to-cell communication (i.e., quorum sensing), and is a promising antipathogenic strategy to control bacterial infection via inhibition of virulence factor expression and biofilm formation. QQ enzyme AiiO-AIO6 from Ochrobactrum sp. M231 has several excellent properties and shows biotherapeutic potential against important bacterial pathogens of aquatic species. AiiO-AIO6 can be secretory expressed in Bacillus subtilis via a non-classical secretion pathway. To improve AiiO-AIO6 production, four intracellular protease-deletion mutants of B. subtilis 1A751 were constructed by individually knocking out the intracellular protease-encoding genes (tepA, ymfH, yrrN and ywpE). The AiiO-AIO6 expression plasmid pWB-AIO6BS was transformed into the B. subtilis 1A751 and its four intracellular protease-deletion derivatives. Results showed that all recombinant intracellular protease-deletion derivatives (BSΔtepA, BSΔymfH, BSΔyrrN and BSΔywpE) had a positive impact on AiiO-AIO6 production. The highest amount of AiiO-AIO6 extracellular production of BSΔywpE in shake flask reached 1416.47 U/mL/OD600, which was about 121% higher than that of the wild-type strain. Furthermore, LC–MS/MS analysis of the degrading products of 3-oxo-C8-HSL by purification of AiiO-AIO6 indicated that AiiO-AIO6 was an AHL-lactonase which hydrolyzes the lactone ring of AHLs. Phylogenetic analysis showed that AiiO-AIO6 was classified as a member of the α/β hydrolase family with a conserved “nucleophile-acid-histidine” catalytic triad. In summary, this study showed that intracellular proteases were responsible for the reduced yields of heterologous proteins and provided an efficient strategy to enhance the extracellular production of AHL lactonase AiiO-AIO6.
Forfattere
Hainie Zha Yuxin Miao Tiantian Wang Yue Li Jing Zhang Weichao Sun Zhengqi Feng Krzysztof KusnierekSammendrag
Optimizing nitrogen (N) management in rice is crucial for China’s food security and sustainable agricultural development. Nondestructive crop growth monitoring based on remote sensing technologies can accurately assess crop N status, which may be used to guide the in-season site-specific N recommendations. The fixed-wing unmanned aerial vehicle (UAV)-based remote sensing is a low-cost, easy-to-operate technology for collecting spectral reflectance imagery, an important data source for precision N management. The relationships between many vegetation indices (VIs) derived from spectral reflectance data and crop parameters are known to be nonlinear. As a result, nonlinear machine learning methods have the potential to improve the estimation accuracy. The objective of this study was to evaluate five different approaches for estimating rice (Oryza sativa L.) aboveground biomass (AGB), plant N uptake (PNU), and N nutrition index (NNI) at stem elongation (SE) and heading (HD) stages in Northeast China: (1) single VI (SVI); (2) stepwise multiple linear regression (SMLR); (3) random forest (RF); (4) support vector machine (SVM); and (5) artificial neural networks (ANN) regression. The results indicated that machine learning methods improved the NNI estimation compared to VI-SLR and SMLR methods. The RF algorithm performed the best for estimating NNI (R2 = 0.94 (SE) and 0.96 (HD) for calibration and 0.61 (SE) and 0.79 (HD) for validation). The root mean square errors (RMSEs) were 0.09, and the relative errors were <10% in all the models. It is concluded that the RF machine learning regression can significantly improve the estimation of rice N status using UAV remote sensing. The application machine learning methods offers a new opportunity to better use remote sensing data for monitoring crop growth conditions and guiding precision crop management. More studies are needed to further improve these machine learning-based models by combining both remote sensing data and other related soil, weather, and management information for applications in precision N and crop management.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Tatsiana Espevig Karin Normann Marina Usoltseva Kate Entwistle Jo Anne Crouch Trygve S. AamlidSammendrag
Det er ikke registrert sammendrag
Forfattere
Tatsiana Espevig Karin Normann Marina Usoltseva Kate Entwistle Jo Anne Crouch Trygve S. AamlidSammendrag
Det er ikke registrert sammendrag
Forfattere
Lisa Magdalena Rossbach Deborah H Oughton Erica Maremonti Claire Coutris Dag Anders BredeSammendrag
The current study provides an in vivo analysis of the production of reactive oxygen species (ROS) and oxidative stress in the nematode Caenorhabditis elegans following exposure to EU reference silver nanoparticles NM300K and AgNO3. Induction of antioxidant defenses was measured through the application of a SOD-1 reporter, and the HyPer and GRX biosensor strains to monitor changes in the cellular redox state. Both forms of Ag resulted in an increase in sod-1 expression, elevated H2O2 levels and an imbalance in the cellular GSSG/GSH redox status. Microscopy analysis of the strains revealed that AgNO3 induced ROS-related effects in multiple tissues, including the pharynx, intestinal cells and muscle tissues. In contrast, NM300K resulted in localized ROS production and oxidative stress, specifically in tissues surrounding the intestinal lumen. This indicates that Ag from AgNO3 exposure was readily transported across the whole body, while Ag or ROS from NM300K exposure was predominantly confined within the luminal tissues. Concentrations resulting in an increase in ROS production and changes in GSSG/GSH ratio were in line with the levels associated with observed physiological toxic effects. However, sod-1 was not induced at the lowest Ag concentrations, although reprotoxicity was seen at these levels. While both forms of Ag caused oxidative stress, impaired development, and reprotoxicity, the results suggest different involvement of ROS production to the toxic effects of AgNO3 versus NM300K.
Forfattere
Camilla Lorange Lindberg Hans Martin Hanslin Marian Schubert Thomas Marcussen Ben Trevaskis Jill Christine Preston Siri FjellheimSammendrag
Semelparous annual plants flower a single time during their 1‐yr life cycle, investing much of their energy into rapid reproduction. By contrast, iteroparous perennial plants flower multiple times over several years, and partition their resources between reproduction and persistence. To which extent evolutionary transitions between life‐cycle strategies are internally constrained at the developmental, genetic and phylogenetic level is unknown. Here we study the evolution of life‐cycle strategies in the grass subfamily Pooideae and test if transitions between them are facilitated by evolutionary precursors. We integrate ecological, life‐cycle strategy and growth data in a phylogenetic framework. We investigate if growth traits are candidates for a precursor. Species in certain Pooideae clades are predisposed to evolve annuality from perenniality, potentially due to the shared inheritance of specific evolutionary precursors. Seasonal dry climates, which have been linked to annuality, were only able to select for transitions to annuality when the precursor was present. Allocation of more resources to above‐ground rather than below‐ground growth is a candidate for the precursor. Our findings support the hypothesis that only certain lineages can respond quickly to changing external conditions by switching their life‐cycle strategy, likely due to the presence of evolutionary precursors.
Forfattere
Kjetil FadnesSammendrag
Gjennom tildelingsbrev frå LMD har NIBIO fått i oppdrag å utvikle rapporteringssystem for jordvernpolitikken. Som ledd i dette har vi undersøkt korleis ein kan koble ferske kartdata for bygningar og vegar mot AR5 for å gje eit estimat på årleg nedbygging av dyrka jord. Resultata tilseier at det er mogleg å gjennomføre årlege beregningar som fanger opp ein stor del av utbygginga, men at det er noko usikkerheit knytta til metoden. Det vert pekt på nokre tiltak for å forbetre metoden og gje tal på usikkerheit knytt til estimatet. Det vert også pekt på måtar å få fram konsekvensar for matproduksjon og økosystemtenester.
Sammendrag
«Landbruk over hele landet» er et av fire hovedmål i norsk landbrukspolitikk. Denne rapporten dokumenterer et forsøk på å utvikle en metode for å kvantifisere måloppnåelse på dette området. Forsøket er begrenset til jordbruket, og vi har valgt fire binære indikatorer på delområdenivå. Indikatorene formidler hvorvidt et område oppfyller ulike, på forhånd definerte minstekrav. Indikatorene er i) antall aktive jordbruksbedrifter, ii) andel aktive søkere i forhold til alle registrerte landbrukseiendommer, iii) bruk av utmarksressursene og iv) jordbruksareal i drift. Basert på disse indikatorene beregnes en indeks som kan gi grunnlag for en samlet vurdering av måloppnåelsen. Resultatene viser store forskjeller i de ulike regionene, med Trøndelag på topp og Nord-Norge på bunn.
Sammendrag
Innføring av obligatorisk individmerking av tamrein i Norge ble vedtatt av Stortinget 13. juni 2019. NIBIO har i denne rapporten belyst hvilke merkemetoder for individmerking som finnes på markedet i dag og hvordan disse egner seg for bruk i reindrifta. Kunnskap om disse og individmerking generelt i næringa, forvaltningen og reindriftsmyndighetene er innhentet gjennom utstrakt kontakt med en rekke informanter. Mulighetene og utfordringene som ligger i individmerking for næring, forvaltning og myndigheter er undersøkt og kartlagt. NIBIO har belyst en del punkter som anbefales for veien videre vedrørende innføring av individmerking i reindriften. NIBIO har også foreslått pilotprosjekter som kan/bør gjennomføres for å forberede reindriften på innføring av individmerking, samt forbedrer dagens løsninger for elektronisk individmerking slik at disse blir driftssikre, kostnadslave, møter næringens behov og nytte og samtidig gir myndigheter og forvaltning ny kunnskap om Norges tamrein...