| 1. |
- Lehmann, Gerlind U. C., et al.
(författare)
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The auditory system of non-calling grasshoppers (Melanoplinae Podismini) and the evolutionary regression of their tympanal ears
- 2010
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Ingår i: Journal of Comparative Physiology A. Sensory, neural, and behavioral physiology. - : Springer Science and Business Media LLC. - 0340-7594 .- 1432-1351. ; 196:11, s. 807-816
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Tidskriftsartikel (refereegranskat)abstract
- Reduction of tympanal hearing organs is repeatedly found amongst insects and is associated with weakened selection for hearing. There is also an associated wing reduction, since flight is no longer required to evade bats. Wing reduction may also affect sound production. Here, the auditory system in four silent grasshopper species belonging to the Podismini is investigated. In this group, tympanal ears occur but sound signalling does not. The tympanal organs range from fully developed to remarkably reduced tympana. To evaluate the effects of tympanal regression on neuronal organisation and auditory sensitivity, the size of wings and tympana, sensory thresholds and sensory central projections are compared. Reduced tympanal size correlates with a higher auditory threshold. The threshold curves of all four species are tuned to low frequencies with a maximal sensitivity at 3-5 kHz. Central projections of the tympanal nerve show characteristics known from fully tympanate acridid species, so neural elements for tympanal hearing have been strongly conserved across these species. The results also confirm the correlation between reduction in auditory sensitivity and wing reduction. It is concluded that the auditory sensitivity of all four species may be maintained by stabilising selective forces, such as predation.
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| 2. |
- Camenzind, Tessa, et al.
(författare)
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Arbuscular mycorrhizal fungal and soil microbial communities in African Dark Earths
- 2018
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Ingår i: FEMS Microbiology Ecology. - : Oxford University Press (OUP). - 0168-6496 .- 1574-6941. ; 94:4
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Tidskriftsartikel (refereegranskat)abstract
- The socio-economic values of fertile and carbon-rich Dark Earth soils are well described from the Amazon region. Very recently, Dark Earth soils were also identified in tropical West Africa, with comparable beneficial soil properties and plant growth-promoting effects. The impact of this management technique on soil microbial communities, however, is less well understood, especially with respect to the ecologically relevant group of arbuscular mycorrhizal (AM) fungi. Thus, we tested the hypotheses that (1) improved soil quality in African Dark Earth (AfDE) will increase soil microbial biomass and shift community composition and (2) concurrently increased nutrient availability will negatively affect AM fungal communities. Microbial communities were distinct in AfDE in comparison to adjacent sites, with an increased fungal:bacterial ratio of 71%, a pattern mainly related to shifts in pH. AM fungal abundance and diversity, however, did not differ despite clearly increased soil fertility in AfDE, with 3.7 and 1.7 times greater extractable P and total N content, respectively. The absence of detrimental effects on AM fungi, often seen following applications of inorganic fertilizers, and the enhanced role of saprobic fungi relevant for mineralization and C sequestration support previous assertions of this management type as a sustainable alternative agricultural practice.
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| 3. |
- Conlon, Thomas M, et al.
(författare)
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Inhibition of LTβR signalling activates WNT-induced regeneration in lung
- 2020
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 588:7836, s. 151-156
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Tidskriftsartikel (refereegranskat)abstract
- Lymphotoxin β-receptor (LTβR) signalling promotes lymphoid neogenesis and the development of tertiary lymphoid structures1,2, which are associated with severe chronic inflammatory diseases that span several organ systems3-6. How LTβR signalling drives chronic tissue damage particularly in the lung, the mechanism(s) that regulate this process, and whether LTβR blockade might be of therapeutic value have remained unclear. Here we demonstrate increased expression of LTβR ligands in adaptive and innate immune cells, enhanced non-canonical NF-κB signalling, and enriched LTβR target gene expression in lung epithelial cells from patients with smoking-associated chronic obstructive pulmonary disease (COPD) and from mice chronically exposed to cigarette smoke. Therapeutic inhibition of LTβR signalling in young and aged mice disrupted smoking-related inducible bronchus-associated lymphoid tissue, induced regeneration of lung tissue, and reverted airway fibrosis and systemic muscle wasting. Mechanistically, blockade of LTβR signalling dampened epithelial non-canonical activation of NF-κB, reduced TGFβ signalling in airways, and induced regeneration by preventing epithelial cell death and activating WNT/β-catenin signalling in alveolar epithelial progenitor cells. These findings suggest that inhibition of LTβR signalling represents a viable therapeutic option that combines prevention of tertiary lymphoid structures1 and inhibition of apoptosis with tissue-regenerative strategies.
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| 4. |
- Hale, Sarah E., et al.
(författare)
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Effects of Chemical, Biological, and Physical Aging As Well As Soil Addition on the Sorption of Pyrene to Activated Carbon and Biochar
- 2011
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 45:24, s. 10445-10453
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the suitability of biochar and activated carbon (AC) for contaminated soil remediation is investigated by determining the sorption of pyrene to both materials in the presence and absence of soil and before as well as after aging. Biochar and AC were aged either alone or mixed with soil via exposure to (a) nutrients and microorganisms (biological), (b) 60 and 110 degrees C (chemical), and (c) freeze-thaw cycles (physical). Before and after aging, the pH, elemental composition, cation exchange capacity (CEC), microporous SA, and sorption isotherms of pyrene were quantified. Aging at 110 degrees C altered the physicochemical properties of all materials to the greatest extent (for example, pH increased by up to three units and CEC by up to 50% for biochar). Logarithmic K(Fr) values ranged from 7.80 to 8.21 (ng kg(-1)) (ng L(-1))(-nF) for AC and 5.22 to 6.21 (ng kg(-1))(ng L(-1))(-nF) for biochar after the various aging regimes. Grinding biochar to a smaller particle size did not significantly affect the sorption of d(10) pyrene, implying that sorption processes operate on the subparticle scale. Chemical aging decreased the sorption of pyrene to the greatest extent (up to 1.8 log unit for the biochar+soil). The sorption to AC was affected more by the presence of soil than the sorption to biochar was. Our results suggest that AC and biochar have a high sorption capacity for pyrene that is maintained both in the presence of soil and during harsh aging. Both materials could therefore be considered in contaminated land remediation.
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| 5. |
- Hale, Sarah E., et al.
(författare)
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Quantifying the Total and Bioavailable Polycyclic Aromatic Hydrocarbons and Dioxins in Biochars
- 2012
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Ingår i: Environmental Science and Technology. - Washington, DC : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 46:5, s. 2830-2838
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Tidskriftsartikel (refereegranskat)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 degrees 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 mu g g(-1) to 3.27 mu g 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 mu g g(-1) and 45 mu g 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-1 which 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 mu g 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.
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| 6. |
- Hestrin, Rachel, et al.
(författare)
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Synergies between mycorrhizal fungi and microbial communities increase plant nitrogen acquisition
- 2019
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- Nitrogen availability often restricts primary productivity in terrestrial ecosystems. Arbuscular mycorrhizal fungi are ubiquitous symbionts of terrestrial plants and can improve plant nitrogen acquisition, but have a limited ability to access organic nitrogen. Although other soil biota mineralize organic nitrogen into bioavailable forms, they may simultaneously compete for nitrogen, with unknown consequences for plant nutrition. Here, we show that synergies between the mycorrhizal fungus Rhizophagus irregularis and soil microbial communities have a highly non-additive effect on nitrogen acquisition by the model grass Brachypodium distachyon. These multipartite microbial synergies result in a doubling of the nitrogen that mycorrhizal plants acquire from organic matter and a tenfold increase in nitrogen acquisition compared to non-mycorrhizal plants grown in the absence of soil microbial communities. This previously unquantified multipartite relationship may contribute to more than 70 Tg of annually assimilated plant nitrogen, thereby playing a critical role in global nutrient cycling and ecosystem function.
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| 7. |
- Josko, Izabela, et al.
(författare)
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Effect of biochars, activated carbon and multiwalled carbon nanotubes on phytotoxicity of sediment contaminated by inorganic and organic pollutants
- 2013
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Ingår i: Ecological Engineering. - : Elsevier. - 0925-8574 .- 1872-6992. ; 60, s. 50-59
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Tidskriftsartikel (refereegranskat)abstract
- To reduce the risk related with the presence of contaminants in sediments, methods based on the use of adsorbents (mainly activated carbon) are applied. Adsorbents neutralise the contaminants by reducing their mobility, bioavailability and toxicity. The objective of this study was to determine the toxicity of sediment contaminated with organic compounds and heavy metals with and without the addition of selected adsorbents. In the study three carbonaceous materials (CM) potentially useful in remediation were applied: activated carbon (AC), biochars (BC1, BC2), and multi- walled carbon nanotubes (CNTs). The effect of the dose, particle diameter and time of contact between sediment and CM on the effectiveness of the detoxification were estimated. Ecotoxicological assessment was made based on the Phytotoxkit FTM test, using Lepidium sativum as the test plant. The materials tested reduced the negative effect of sediment on L. sativum. The highest effectiveness was achieved after the application of AC (70% reduction of seed germination inhibition, 27.5% reduction of root growth inhibition). The reduction of phytotoxicity of the sediment as a result of addition of BC1, BC2 and CNT varied within the range from 30 to 40% (reduction of seed germination inhibition) and from 17.7 to 28.9% (reduction of root growth inhibition). The reduction of sediment toxicity decreased with decreasing diameter of the biochars applied. Probably because of increasing fouling extension of the time of contact between CM and sediment had an unfavourable effect on the reduction of root growth inhibition in the case of all materials tested.
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| 8. |
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| 9. |
- Lehmann, Johannes, et al.
(författare)
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Persistence of soil organic carbon caused by functional complexity
- 2020
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Ingår i: Nature Geoscience. - : Springer Science and Business Media LLC. - 1752-0894 .- 1752-0908. ; 13, s. 529-534
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Tidskriftsartikel (refereegranskat)abstract
- Soil organic carbon management has the potential to aid climate change mitigation through drawdown of atmospheric carbon dioxide. To be effective, such management must account for processes influencing carbon storage and re-emission at different space and time scales. Achieving this requires a conceptual advance in our understanding to link carbon dynamics from the scales at which processes occur to the scales at which decisions are made. Here, we propose that soil carbon persistence can be understood through the lens of decomposers as a result of functional complexity derived from the interplay between spatial and temporal variation of molecular diversity and composition. For example, co-location alone can determine whether a molecule is decomposed, with rapid changes in moisture leading to transport of organic matter and constraining the fitness of the microbial community, while greater molecular diversity may increase the metabolic demand of, and thus potentially limit, decomposition. This conceptual shift accounts for emergent behaviour of the microbial community and would enable soil carbon changes to be predicted without invoking recalcitrant carbon forms that have not been observed experimentally. Functional complexity as a driver of soil carbon persistence suggests soil management should be based on constant care rather than one-time action to lock away carbon in soils. Dynamic interactions between chemical and biological controls govern the stability of soil organic carbon and drive complex, emergent patterns in soil carbon persistence.
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| 10. |
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