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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2012

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Abstract

To gain insight into the molecular basis contributing to overwintering hardiness, a comprehensive proteomic analysis comparing crowns of Fragaria × ananassa (octoploid strawberry) cultivars that differ in freezing tolerance was conducted. Four cultivars were examined for freeze tolerance and the most cold-tolerant cultivar (‘Jonsok’) and least tolerant cultivar (‘Frida’) were compared with a goal to reveal how freezing tolerance is achieved in this distinctive overwintering structure and to identify potential cold-tolerance associated biomarkers. Supported by univariate and multivariate analysis, a total of 63 spots from 2DE analysis and 135 proteins from label-free quantitative proteomics (LFQP) were identified as significantly differentially expressed in crown tissue from the two strawberry cultivars exposed to 0, 2, and 42 day cold treatment. Proteins identified as cold tolerance associated included molecular chaperones, antioxidants/detoxifying enzymes, metabolic enzymes, pathogenesis related proteins and flavonoid pathway proteins. A number of proteins were newly identified as associated with cold tolerance. Distinctive mechanisms for cold tolerance were characterized for two cultivars. In particular, the ‘Frida’ cold response emphasized proteins specific to flavonoid biosynthesis, while the more freezing tolerant ‘Jonsok’ had a more comprehensive suite of known stress responsive proteins including those involved in antioxidation, detoxification, and disease resistance. The molecular basis for ‘Jonsok’ enhanced cold tolerance can be explained by the constitutive level of a number of proteins that provide a physiological stress-tolerant “poise”.

Abstract

1. Neodiprion sertifer nucleopolyhedrovirus (NeseNPV) is widely used as a viral bio-insecticide against larvae of the European pine sawfly N. sertifer (Geoff.) (Hymenoptera: Diprionidae), which is one of the most harmful defoliators of pines in Northern Europe. A major obstacle to studying this pathogenic virus in nature is the difficulty of confirming and quantifying the presence of NeseNPV. 2. In the present study, we developed real-time polymerase chain reaction (PCR) primers, based on the caspid gene 39 sequence, for the specific and quantitative detection of NeseNPV. The quantitative real-time PCR (qPCR) assay can detect virus from any substrate tested, including different insect life stages (egg, larval, adult), pine foliage, and litter or ground vegetation. The reproducible detection limit for the real-time assay is 0.013 pg of viral DNA (0.013 × 10−12 g), corresponding to 136 viral genomes or approximately one to seven virus occlusion bodies per sample. 3. qPCR is a specific, quantitative, sensitive, reliable and flexible procedure, and is a good supplement to conventional microscopy- or bioassay-based methods for detection of the virus. We have used qPCR to quantify the level of NeseNPV in samples collected in the field after aerial application of the virus, and demonstrated significantly higher virus levels in sawfly larvae from sprayed areas compared with unsprayed control areas 4 weeks after spraying. 4. This qPCR assay can be used to determine important aspects of the biology of NeseNPV (e.g. virus levels in different insect life stages and in their microhabitats on pine foliage and in forest litter).

To document

Abstract

Biochar soil amendment is advocated to mitigate climate change and improve soil fertility. A concern though, is that during biochar preparation PAHs and dioxins are likely formed. These contaminants can possibly be present in the biochar matrix and even bioavailable to exposed organisms. Here we quantify total and bioavailable PAHs and dioxins in a suite of over 50 biochars produced via slow pyrolysis between 250 and 900 °C, using various methods and biomass from tropical, boreal, and temperate areas. These slow pyrolysis biochars, which can be produced locally on farms with minimum resources, are also compared to biochar produced using the industrial methods of fast pyrolysis and gasification. Total concentrations were measured with a Soxhlet extraction and bioavailable concentrations were measured with polyoxymethylene passive samplers. Total PAH concentrations ranged from 0.07 μg g–1 to 3.27 μg g–1 for the slow pyrolysis biochars and were dependent on biomass source, pyrolysis temperature, and time. With increasing pyrolysis time and temperature, PAH concentrations generally decreased. These total concentrations were below existing environmental quality standards for concentrations of PAHs in soils. Total PAH concentrations in the fast pyrolysis and gasification biochar were 0.3 μg g–1 and 45 μg g–1, respectively, with maximum levels exceeding some quality standards. Concentrations of bioavailable PAHs in slow pyrolysis biochars ranged from 0.17 ng L–1 to 10.0 ng L–1which is lower than concentrations reported for relatively clean urban sediments. The gasification produced biochar sample had the highest bioavailable concentration (162 ± 71 ng L–1). Total dioxin concentrations were low (up to 92 pg g–1) and bioavailable concentrations were below the analytical limit of detection. No clear pattern of how strongly PAHs were bound to different biochars was found based on the biochars’ physicochemical properties.