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  • Directory of Open Access Journals (DOAJ)  (8)
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  • 1
    Language: English
    In: Forests, 01 February 2017, Vol.8(2), p.37
    Description: More intensive removal of woody biomass for the bio-economy will disrupt litter and succession cycles. Especially at risk is the retention of fine and coarse woody debris (FWD and CWD), crucial factors in forest biodiversity and nutrient cycling. However, to what extent CWD affects soil functioning remains unknown, and is seldom considered. From 32 paired test–reference points in eight Fagus sylvatica (L.) stands throughout Southwest Germany, CWD significantly increased soil C/N ratios, base saturation, and possibly pH. CWD-induced changes in soil porosity, available water capacity, and total organic carbon depended on site and CWD characteristics. As such, CWD can be viewed as a “pedogenic hot-spot” of concentrated biogeochemical and -physical processes with outsized effects on soil functioning and development. CWD management for soil functioning should consider site and tree species specific volume thresholds, timed rotations, and spatial densities, but appropriate implementation requires further research to define best management practices. If successful, overall forest resilience as well as soil functioning and productivity can be improved.
    Keywords: Soil Management ; Silviculture ; Disturbances ; Fagus Sylvatica ; Biodiversity ; Bioeconomy ; Forestry
    E-ISSN: 1999-4907
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  • 2
    Language: English
    In: Sci Rep, 2017, Vol.7(1), pp.13243-13243
    Description: Naturally produced by microbial processes in soil, nitrous oxide (NO) is an important greenhouse gas contributing to climate change. Accordingly, there is a need to accurately quantify the capability of forest ecosystems to exchange NO with the atmosphere. While NO emissions from soils have been well studied, trees have so far been overlooked in NO inventories. Here, we show that stems of mature beech trees (Fagus sylvatica) may act as a substantial sink of NO from the atmosphere under conditions of soils consuming NO. Consistent consumption of NO by all stems investigated (ranging between −2.4 and −3.8 µg m h) is a novel finding in contrast to current studies presenting trees as NO emitters. To understand these fluxes, NO exchange of photoautotrophic organisms associated with beech bark (lichens, mosses and algae) was quantified under laboratory conditions. All these organisms were net NO sinks at full rehydration and temperature of 25 °C. The consumption rates were comparable to stem consumption rates measured under field conditions. Cryptogamic stem covers could be a relevant sink of NO in European beech forests.
    Keywords: Article;
    ISSN: 2045-2322
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  • 3
    Language: English
    In: Frontiers in microbiology, 2015, Vol.6, pp.163
    Description: Long-term irrigation with untreated wastewater can lead to an accumulation of antibiotic substances and antibiotic resistance genes in soil. However, little is known so far about effects of wastewater, applied for decades, on the abundance of IncP-1 plasmids and class 1 integrons which may contribute to the accumulation and spread of resistance genes in the environment, and their correlation with heavy metal concentrations. Therefore, a chronosequence of soils that were irrigated with wastewater from 0 to 100 years was sampled in the Mezquital Valley in Mexico in the dry season. The total community DNA was extracted and the absolute and relative abundance (relative to 16S rRNA genes) of antibiotic resistance genes (tet(W), tet(Q), aadA), class 1 integrons (intI1), quaternary ammonium compound resistance genes (qacE+qacEΔ1) and IncP-1 plasmids (korB) were quantified by real-time PCR. Except for intI1 and qacE+qacEΔ1 the abundances of selected genes were below the detection limit in non-irrigated soil. Confirming the results of a previous study, the absolute abundance of 16S rRNA genes in the samples increased significantly over time (linear regression model, p 〈 0.05) suggesting an increase in bacterial biomass due to repeated irrigation with wastewater. Correspondingly, all tested antibiotic resistance genes as well as intI1 and korB significantly increased in abundance over the period of 100 years of irrigation. In parallel, concentrations of the heavy metals Zn, Cu, Pb, Ni, and Cr significantly increased. However, no significant positive correlations were observed between the relative abundance of selected genes and years of irrigation, indicating no enrichment in the soil bacterial community due to repeated wastewater irrigation or due to a potential co-selection by increasing concentrations of heavy metals.
    Keywords: Incp-1 Plasmids ; Aminoglycoside Resistance ; Class 1 Integrons ; Quaternary Ammonium Compound Resistance ; Tetracycline Resistance ; Wastewater Irrigation
    ISSN: 1664-302X
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  • 4
    Language: English
    In: Respiratory Research, 01 July 2010, Vol.11(1), p.93
    Description: Abstract Background Legionella pneumophila is an important causative agent of severe pneumonia in humans. Human alveolar epithelium and macrophages are effective barriers for inhaled microorganisms and actively participate in the initiation of innate host defense. The beta defensin-3 (hBD-3), an antimicrobial peptide is an important component of the innate immune response of the human lung. Therefore we hypothesize that hBD-3 might be important for immune defense towards L. pneumophila. Methods We investigated the effects of L. pneumophila and different TLR agonists on pulmonary cells in regard to hBD-3 expression by ELISA. Furthermore, siRNA-mediated inhibition of TLRs as well as chemical inhibition of potential downstream signaling molecules was used for functional analysis. Results L. pneumophila induced release of hBD-3 in pulmonary epithelium and alveolar macrophages. A similar response was observed when epithelial cells were treated with different TLR agonists. Inhibition of TLR2, TLR5, and TLR9 expression led to a decreased hBD-3 expression. Furthermore expression of hBD-3 was mediated through a JNK dependent activation of AP-1 (c-Jun) but appeared to be independent of NF-κB. Additionally, we demonstrate that hBD-3 elicited a strong antimicrobial effect on L. pneumophila replication. Conclusions Taken together, human pulmonary cells produce hBD-3 upon L. pneumophila infection via a TLR-JNK-AP-1-dependent pathway which may contribute to an efficient innate immune defense.
    Keywords: Medicine
    ISSN: 1465-9921
    E-ISSN: 1465-993X
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  • 5
    Language: English
    In: Forests, 01 September 2017, Vol.8(10), p.358
    Description: Forest harvesting removes and redistributes nutrients through felling and forwarding. Substantial quantities of nutrients can accumulate in brash mats on permanent skid trails, but their availability and uptake after multiple thinnings on soils susceptible to leaching are unknown. In this study, we modeled the deposition of base cations and phosphorus on a permanent skid trail after five thinnings of a Picea abies (L.) Karst. stand, and measured the resulting nutrient stocks in both the forest floor and mineral soil. An estimated 35%, 44%, 41%, and 61% of harvested Ca, K, Mg, and P, respectively, were redistributed to the skid trail. Of those deposited stocks, 32–65% of nutrients remained in decomposed brash material on the skid trail. Mineral soil stocks for Ca, K, and P were significantly higher in the skid trail than in the stand, which included minor increases in bioavailable pools. Skid trail root densities were not lower than the stand while bulk densities were only partially higher. Both would not limit nutrient uptake. There were no significant relations between needle nutrient concentrations and distance to the skid trail. Altogether, these results indicate that nutrient uptake from the skid trail was minimal despite their accumulation, chemical availability, and physical accessibility. This suggests that other factors such as liming and frequent thinning disturbances can repress uptake of available nutrients on skid trails.
    Keywords: Soil Management ; Picea Abies ; Brash Mats ; Needle Nutrition ; Whole-Tree Harvesting ; Liming ; Forestry
    E-ISSN: 1999-4907
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  • 6
    Language: English
    In: Forests, 01 August 2019, Vol.10(9), p.726
    Description: The compaction of forest soils can deteriorate soil aeration, leading to decreased CH4 uptake and increased N2O efflux. Black alder (Alnus glutinosa) may accelerate soil structure regeneration as it can grow roots under anaerobic soil conditions. However, symbiotic nitrogen fixation by alder can have undesirable side-effects on greenhouse gas (GHG) fluxes. In this study, we evaluated the possible trade-off between alder-mediated structure recovery and GHG emissions. We compared two directly adjacent 15-year old beech (Fagus sylvatica) and alder stands (loamy texture, pH 5−6), including old planted skid trails. The last soil trafficking on the skid trails took place in 1999. GHG fluxes were measured over one year. Undisturbed plots with beech had a moderately higher total porosity and were lower in soil moisture and soil organic carbon than undisturbed alder plots. No differences in mineral nitrogen were found. N2O emissions in the undisturbed beech stand were 0.4 kg ha−1 y−1 and 3.1 kg ha−1 y−1 in the undisturbed alder stand. CH4 uptake was 4.0 kg ha−1 y−1 and 1.5 kg ha−1 y−1 under beech and alder, respectively. On the beech planted skid trail, topsoil compaction was still evident by reduced macro porosity and soil aeration; on the alder planted skid trail, soil structure of the uppermost soil layer was completely recovered. Skid trail N2O fluxes under beech were five times higher and CH4 oxidation was 0.6 times lower compared to the adjacent undisturbed beech stand. Under alder, no skid-trail-effects on GHG fluxes were evident. Multiple regression modelling revealed that N2O and CH4 emissions were mainly governed by soil aeration and soil temperature. Compared to beech, alder considerably increased net fluxes of GHG on undisturbed plots. However, for skid trails we suggest that black alder improves soil structure without deterioration of the stand's greenhouse gas balance, when planted only on the compacted areas.
    Keywords: Soil Compaction ; Skid Trails ; Black Alder ; Alnus Glutinosa ; Greenhouse Gas Fluxes ; Soil Structure Recovery ; Forestry
    E-ISSN: 1999-4907
    Source: Directory of Open Access Journals (DOAJ)
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  • 7
    Language: English
    In: Journal of Hydrology X, 01 January 2019, Vol.2
    Description: The choice of uranine (UR) and sulforhodamine B (SRB) as hydrological tracers has recently been questioned since they might interact with the soil or become degraded. In this context, microbiological degradation of UR and SRB and the factors influencing it remain poorly studied. Here, we conducted a long-term mesocosm experiment where the effects of plants and hydrologic conditions on the dissipation and degradation of UR and SRB was separately investigated. Mass balances were combined with excitation emission matrix (EEM) fluorescence spectroscopy to characterize microbially-derived organic matter. Results revealed that most of SRB accumulated in the sand while UR was mainly found in the pore water. The estimated degradation of UR and SRB was greater in the treatments with plants and under unsaturated conditions. Overall, UR exhibited higher presumable degradation than SRB. Two components were identified by parallel factor analysis of the EEMs in addition to the UR-related component (U), one humic-like of high molecular weight primarily derived from terrestrial or soil organic matter sources (A + C) and a second humic-like of lower molecular weight related to recent microbial activity (M). A high positive correlation (Spearman’s rho = 0.74, p 〈 0.001) between M and U suggested a possible link, in which the presence of UR fostered microbial processes, thus supporting the hypothesis of biodegradation of UR, which seemed independent of the presence of plants, whereas it was not possible to point out such a correlation for SRB. These results show for the first time that plants and the alternation of oxic and anoxic conditions are favourable to increase degradation of UR and SRB and that microbiological degradation can be involved and dominant in UR dissipation. Keywords: Hydrological tracers, Wetland mesocosm, Degradation, Sorption, Excitation-emission matrix fluorescence spectroscopy
    ISSN: 2589-9155
    Source: Directory of Open Access Journals (DOAJ)
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  • 8
    Language: English
    In: NATURE COMMUNICATIONS, 2019
    Description: The effectiveness of most cancer targeted therapies is short-lived. Tumors often develop resistance that might be overcome with drug combinations. However, the number of possible combinations is vast, necessitating data-driven approaches to find optimal patient-specific treatments. Here we report AstraZeneca's large drug combination dataset, consisting of 11,576 experiments from 910 combinations across 85 molecularly characterized cancer cell lines, and results of a DREAM Challenge to evaluate computational strategies for predicting synergistic drug pairs and biomarkers. 160 teams participated to provide a comprehensive methodological development and benchmarking. Winning methods incorporate prior knowledge of drug-target interactions. Synergy is predicted with an accuracy matching biological replicates for 〉60% of combinations. However, 20% of drug combinations are poorly predicted by all methods. Genomic rationale for synergy predictions are identified, including ADAM17 inhibitor antagonism when combined with PIK3CB/D inhibition contrasting to synergy when combined with other PI3K-pathway inhibitors in PIK3CA mutant cells.
    Keywords: Androgen Receptor ; Breast-Cancer ; Gene ; Cell ; Inhibition ; Resistance ; Pathway ; Mutations ; Landscape ; Resource
    ISSN: 2041-1723
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