| 1. |
- Anderbrant, Olle, et al.
(författare)
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Pheromone of the elm bark beetle Scolytus laevis (Coleoptera Scolytidae) : stereoisomers of 4-methyl-3-heptanol reduce interspecific competition
- 2010
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Ingår i: Chemoecology. - : Springer Science and Business Media LLC. - 0937-7409 .- 1423-0445. ; 20:3, s. 179-187
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Tidskriftsartikel (refereegranskat)abstract
- Stereoisomers of 4-methyl-3-heptanol (MH) are pheromone components of several Scolytus bark beetles. The elm bark beetle Scolytus laevis (Coleoptera: Scolytidae) has in previous studies been caught in traps baited with commercial MH containing all four stereoisomers, but the lure has been considered a weak attractant. In this study, we addressed the question whether stereospecific responses by S. laevis to stereoisomers of MH might contribute to its niche separation from other sympatric Scolytus species. Using GC-MS, we analyzed extracts of hindguts and abdomens from male and female S. laevis and the sympatric S. triarmatus. We also tested all four MH-stereoisomers individually and in combinations in the field to determine their role for S. laevis. All four stereoisomers were synthesized via a boronic ester method with 1,2-dicyclohexylethanediol as chiral director. In addition, the (3S,4R)-stereoisomer of MH was prepared through enantioselective, lipase-mediated transesterification of a mixture of the four stereoisomers of MH. Females of both species contained small amounts of syn-MH, and males contained trace amounts of anti-MH. The anti stereoisomer (3R,4S)-MH was attractive to male and female S. laevis, whereas the syn stereoisomer (3S,4S)-MH acted as an inhibitor or deterrent and reduced the catch when added to the attractive isomer. The syn isomer is the main aggregation pheromone component of the larger and sympatric S. scolytus and possibly also of S. triarmatus. The avoidance response of S. laevis to the (3S,4S)-stereoisomer may reduce interspecific competition for host trees.
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| 2. |
- Wu, Mousong, et al.
(författare)
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Coupled water transport and heat flux in seasonally frozen soils : uncertainties identification in multi-site calibration
- 2020
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Ingår i: Environmental Earth Sciences. - : Springer Nature. - 1866-6280 .- 1866-6299. ; 79:23
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Tidskriftsartikel (refereegranskat)abstract
- The modeling of seasonally frozen soils is significant for understanding the hydrological process in cold regions. The water and heat transports of two seasonally frozen sites in northern China were simulated with the process-oriented CoupModel, and a more efficient Monte Carlo based method was employed to identify the uncertainties in multi-site calibration. Results showed that water and heat measured at different sites could be explained by 15 merged parameters includingFreezepoint FWi (d(1)), EquilAdjustPsi (psi(eg)), AlbedoKExp (ka), RoughLBareSoilMom (z0M) etc. with common ranges to some extent and three parameters MinimumCondValue (k(min,uc)), WindLessExchangeSoil (r(a,max)(-1)), and SThermalCondCoef (s(k)) related to soil hydraulic conductivity, surface aerodynamic resistance and snow thermal conductivity respectively were identified to be site-dependent with site-specific ranges. The promotion in performance indices of interest variables indicated that the proposed systematic method had the potential to improve the multi-site simulation of heat and water in frozen soils based on CoupModel. However, the range ratios and posterior distributions of the merged parameters indicated the model structural uncertainty in CoupModel. And the comparison of the simulated variables between two sites demonstrated that the model structure uncertainty originated from the lack of consideration for the detailed processes related to ice cover and freezing point depression induced by soil solute. More detailed information on study sites as well as consideration of more detailed processes in frozen soil water-energy balance will expand the scope of model application in cold regions.
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| 3. |
- Jarvis, Åsa, et al.
(författare)
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Activity and composition of ammonia oxidizing bacterial communities and emission dynamics of NH3 and N2O in a compost reactor treating organic household waste
- 2009
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Ingår i: JOURNAL OF APPLIED MICROBIOLOGY. - : Oxford University Press (OUP). - 1364-5072 .- 1365-2672. ; 106:5, s. 1502-1511
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Tidskriftsartikel (refereegranskat)abstract
- To monitor emissions of NH3 and N2O during composting and link these to ammonia oxidation rates and the community structure of ammonia oxidizing bacteria (AOB). A laboratory-scale compost reactor treating organic household waste was run for 2 months. NH3 emissions peaked when pH started to increase. Small amounts of N2O and CH4 were also produced. In total, 16% and less than 1% of the initial N was lost as NH3-N and N2O-N respectively. The potential ammonia oxidation rate, determined by a chlorate inhibition assay, increased fourfold during the first 9 days and then remained high. Initially, both Nitrosospira and Nitrosomonas populations were detected using DGGE analysis of AOB specific 16S rRNA fragments. Only Nitrosomonas europaea was detected under thermophilic conditions, but Nitrosospira populations re-established during the cooling phase. Thermophilic conditions favoured high potential ammonia oxidation rates, suggesting that ammonia oxidation contributed to reduced NH3 emissions. Small but significant amounts of N2O were emitted during the thermophilic phase. The significance of different AOBs detected in the compost for ammonia oxidation is not clear. This study shows that ammonia oxidation occurs at high temperature composting and therefore most likely reduces NH3 emissions.
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| 4. |
- Johansson, Eva, et al.
(författare)
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Wheat gluten polymer structures : The impact of genotype, environment, and processing on their functionality in various applications
- 2013
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Ingår i: Cereal Chemistry. - 0009-0352 .- 1943-3638. ; 90:4, s. 367-376
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Tidskriftsartikel (refereegranskat)abstract
- For a number of applications, gluten protein polymer structures are of the highest importance in determining end-use properties. The present article focuses on gluten protein structures in the wheat grain, genotype- and environment-related changes, protein structures in various applications, and their impact on quality. Protein structures in mature wheat grain or flour are strongly related to end-use properties, although influenced by genetic and environment interactions. Nitrogen availability during wheat development and genetically determined plant development rhythm are the most important parameters determining the gluten protein polymer structure, although temperature during plant development interacts with the impact of the mentioned parameters. Glutenin subunits are the main proteins incorporated in the gluten protein polymer in extracted wheat flour. During dough mixing, gliadins are also incorporated through disulfide-sulfhydryl exchange reactions. Gluten protein polymer size and complexity in the mature grain and changes during dough formation are important for breadmaking quality. When using the gluten proteins to produce plastics, additional proteins are incorporated in the polymer through disulfide-sulfhydryl exchange, sulfhydryl oxidation, β-eliminations with lanthionine formation, and isopeptide formation. In promising materials, the protein polymer structure is changed toward β-sheet structures of both intermolecular and extended type and a hexagonal close-packed structure is found. Increased understanding of gluten protein polymer structures is extremely important to improve functionality and end-use quality of wheat- and gluten-based products.
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| 5. |
- Muneer, Faraz, et al.
(författare)
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Innovative Gliadin/Glutenin and Modified Potato Starch Green Composites : Chemistry, Structure, and Functionality Induced by Processing
- 2016
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 4:12, s. 6332-6343
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we combined two wheat proteins, gliadin (Gli)/glutenin (GT), and modified potato starch (MPS) into composites using extrusion. In the Gli/GT MPS composites, we studied the structural dynamics of proteins and starch, protein starch interactions, protein properties, and composite morphology in relation to mechanical and barrier properties. Materials with different ratios of Gli/GT and MPS were extruded using either glycerol or glycerol water at 110 and 130 degrees C. For the first time, a hierarchical hexagonal structure of Gli proteins was observed in Gli MPS composite at both extrusion temperatures. The higher temperature (130 degrees C) induced a higher degree of protein cross-links, an increase in the polymer size, and formation of beta-sheets compared to 110 degrees C. The combination of plasticizers (glycerol and water) favored a micro-structural morphology with improved gelatinization of starch, processability, as well as strength, stiffness, and extensibility of GT MPS composites. The highest amount of the oxidized proteins was observed in the samples with the highest protein content and at high extrusion temperature. The Gli- and GT MPS (30/70) samples showed promising oxygen barrier properties under ambient testing conditions. These findings provide in-depth information for tailoring the structural functional relationship of the Gli/GT-potato starch composites for their promising use in designing various green materials.
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| 6. |
- Zhang, Jie, et al.
(författare)
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Modeling nitrous oxide emissions from agricultural soil incubation experiments using CoupModel
- 2022
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Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 19:19, s. 4811-4832
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Tidskriftsartikel (refereegranskat)abstract
- Efforts to develop effective climate mitigation strategies for agriculture require methods to estimate nitrous oxide (N2O) emissions from soil. Process-based biogeochemical models have been often used for field- and large-scale estimates, while the sensitivity and uncertainty of model applications to incubation experiments are less investigated. In this study, a process-oriented model (CoupModel) was used to simulate N2O and CO2 fluxes and soil mineral nitrogen (N) contents in a short-term (43 d) factorial incubation experiment (16 treatments). A global sensitivity analysis (GSA) approach, "Morris screening", was applied to quantify parameter sensitivity. The GSA suggested that a higher number of sensitive parameters was associated with N2O flux estimates and that inter-treatment variations in parameter sensitivities were distinguished by soil moisture levels or NO3- content and residue types. Important parameters regarding N2O flux estimates were linked to the decomposability of soil organic matter (e.g., organic C pool sizes) and the denitrification process (e.g., Michaelis constant and denitrifier respiratory rates). After calibration, the model better captured temporal variations and magnitude of gas fluxes and mineral N in unamended soils than in residue-amended soils. Low-magnitude daily and cumulative N2O fluxes were well simulated with mean errors (MEs) close to zero, but the model tended to underestimate N2O fluxes, as observed daily values increased by over 0.1 gNm 2 d 1, in which the major mismatch was due to limited success of the model to describe the high emissions during the first few days after crop residue addition. A larger uncertainty was also seen in the magnitude of pulse emissions by the posterior simulations. We also evaluated ancillary variables regarding N cycling, which indicated that more frequent measurements and additional types of observed data such as soil oxygen content and the microbial sources of emitted N2O are required to further evaluate model performance and biases. The major challenges for calibration were associated with high sensitivities of denitrification parameters to initial soil abiotic conditions and the instantaneous residue amendment. Model structure uncertainties and improved modeling practices in the context of incubation experiments were discussed.
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| 7. |
- Eveborn, David, 1978-, et al.
(författare)
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Phosphorus in soil treatment systems : accumulation and mobility
- 2014
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Ingår i: Water Research. - : Elsevier. - 0043-1354 .- 1879-2448. ; 64, s. 42-52
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Tidskriftsartikel (refereegranskat)abstract
- In several western countries, septic tanks with subsequent soil treatment systems (STS) are a common treatment technique for domestic wastewater in rural areas. However the suitability of STS (especially relatively close to surface waters) can be questioned since the discharge of phosphorus (P) from such effluents is not well known. In this study, six STS in Sweden (11 to 28 years old) were investigated by means of batch and column experiments on samples taken from the unsaturated subsoil beneath the distribution pipes. At all sites the wastewater had clearly influenced the soil. This was observed through decreased pH, increased amounts of oxalate extractable metals and altered P sorption properties. The amount of accumulated P in the STS (defined as the amount of total P in the STS samples minus the amount of total P in unused soil samples) were found to be between 0.32 and 0.87 kg m-3, which in most cases was just a small fraction of the estimated P load (< 30%). Column studies revealed that remarkably high P concentrations (up to 6 mg L-1) were leached from the material when deionized water was applied. However, the response to deionized water varied between the sites. The affinity for P in the soils was well correlated to the amount of oxalate-extractable aluminium (as evidenced by a strong relationship between oxalate-extractable Al and oxalate-extractable P) and generally soils with high content of oxalate extractable Al was also less vulnerable to P leakage.
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| 8. |
- Wang, Chunyu, et al.
(författare)
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Modelling water and energy fluxes with an explicit representation of irrigation under mulch in a maize field
- 2022
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Ingår i: Agricultural and Forest Meteorology. - : Elsevier BV. - 0168-1923 .- 1873-2240. ; 326
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Tidskriftsartikel (refereegranskat)abstract
- Globally, water-saving irrigation plays a vital role in agricultural ecosystems to achieve sustainable food pro-duction under climate change. Irrigation under mulch (IUM) system has been widely used in modern agricultural ecosystems due to its high water use efficiency, but it remains unclear how each component of the water and energy processes responds to this agricultural management practice. Current modeling approaches are inade-quate in investigating the impacts of IUM management on water-energy balance, which have shown more complicated than non-mulched management. Therefore, this study provided an explicit simulation of water and energy fluxes in IUM system using a process-oriented ecosystem model-CoupModel and the three years of the eddy covariance (EC) measurements. Based on Monte Carlo and the multiple model performance evaluation criteria, most of the model sensitive parameters were well constrained and 32 potentially important parameters, e.g., iscovevap, the fraction of mulch coverage, were identified to characterize the impacts of plastic mulching on energy balance and water transport. After proper calibration, the coefficient of determination (R2) for measured and simulated soil temperature (T) and soil water content (SWC) was 0.79 and 0.60, respectively, and the R2 for T and SWC during the validation period were 0.91 and 0.71, respectively. Furthermore, we found that there was a strong coupling between the parameters of the water and energy processes, which would restrict the simulation results due to the correlation between the parameters and the evaluation indices. This study presented a sys-tematic model parameters calibration in the agricultural ecosystem implemented with IUM and provided with a more comprehensive understanding of the water and energy balance in cropland. These results would help agricultural model development with more detailed considerations of the water-saving management.
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| 9. |
- Ahlqvist, Josefin, et al.
(författare)
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Affinity binding of inclusion bodies on supermacroporous monolithic cryogels using labeling with specific antibodies
- 2006
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Ingår i: Journal of Biotechnology. - : Elsevier BV. - 0168-1656 .- 1873-4863. ; 122:2, s. 216-225
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Tidskriftsartikel (refereegranskat)abstract
- A new chromatographic method based on affinity supermacroporous monolithic cryogels is developed for binding and analyzing inclusion bodies during fermentation. The work demonstrated that it is possible to bind specific IgG and IgY antibodies to the 15 and 17 amino acids at the terminus ends of a 33 kDa target protein aggregated as inclusion bodies. The antibody treated inclusion bodies from lysed fermentation broth can be specifically retained in protein A and pseudo-biospecific ligand sulfamethazine modified supermacroporous cryogels. The degree of binding of IgG and IgY treated inclusion bodies to the Protein A and sulfamethazine gels are investigated, as well as the influence of pH on the sulfamethazine ligand. Optimum binding of 78 and 72% was observed on both protein A and sulfamethazine modified cryogel columns, respectively, using IgG labeling of the inclusion bodies. The antibody treated inclusion bodies pass through unretained in the sulfamethazine supermacroporous gel at pH that does not favour the binding between the ligand on the gel and the antibodies on the surface of inclusion bodies. Also the unlabeled inclusion bodies went through the gel unretained, showing no non-specific binding or trapping within the gel. These findings may very well be the foundation for the building of a powerful analytical tool during fermentation of inclusion bodies as well as a convenient way to purify them from fermentation broth. These results also support our earlier findings [Kumar, A., Plieva, F.M., Galaev, I.Yu., Mattiasson, B.. 2003. Affinity fractionation of lymphocytes using a monolithic cyogel. J. Immunol. Methods 283, 185-194] with mammalian cells that were surface labeled with specific antibodies and recognized on protein A supermacroporous gels. A general binding and separation system can be established on antibody binding cryogel affinity matrices.
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| 10. |
- Ahmed, Engy, et al.
(författare)
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Mineral Type Structures Soil Microbial Communities
- 2017
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Ingår i: Geomicrobiology Journal. - : Taylor & Francis. - 0149-0451 .- 1521-0529. ; 34:6, s. 538-545
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Tidskriftsartikel (refereegranskat)abstract
- Soil microorganisms living in close contact with minerals play key roles in the biogeochemical cycling of elements, soil formation, and plant nutrition. Yet, the composition of microbial communities inhabiting the mineralosphere (i.e., the soil surrounding minerals) is poorly understood. Here, we explored the composition of soil microbial communities associated with different types of minerals in various soil horizons. To this effect, a field experiment was set up in which mineral specimens of apatite, biotite, and oligoclase were buried in the organic, eluvial, and upper illuvial horizons of a podzol soil. After an incubation period of two years, the soil attached to the mineral surfaces was collected, and microbial communities were analyzed by means of Illumina MiSeq sequencing of the 16S (prokaryotic) and 18S (eukaryotic) ribosomal RNA genes. We found that both composition and diversity of bacterial, archaeal, and fungal communities varied across the different mineral surfaces, and that mineral type had a greater influence on structuring microbial assemblages than soil horizon. Thus, our findings emphasize the importance of mineral surfaces as ecological niches in soils.
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