Kooperativer Bibliotheksverbund

Berlin Brandenburg

and
and

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Lang, F
  • MEDLINE/PubMed (NLM)  (16)
Type of Medium
Language
Year
  • 1
    Language: English
    In: Science of the Total Environment, 01 December 2015, Vol.535, pp.54-60
    Description: Nanoparticles enter soils through various pathways. In the soil, they undergo various interactions with the solution and the solid phase. We tested the following hypotheses using batch experiments: i) the colloidal stability of Ag NP increases through sorption of soil-borne dissolved organic matter (DOM) and thus inhibits aggregation; ii) the presence of DOM suppresses Ag oxidation; iii) the surface charge of Ag NP governs sorption onto soil particles. Citrate-stabilized and bare Ag NPs were equilibrated with (colloid-free) soil solution extracted from a floodplain soil for 24 h. Nanoparticles were removed through centrifugation. Concentrations of free Ag ions and DOC, the specific UV absorbance at a wavelength of 254 nm, and the absorption ratio α /α were determined in the supernatant. Nanoparticle aggregation was studied using time-resolved dynamic light scattering (DLS) measurement following the addition of soil solution and 1.5 mM Ca solution. To study the effect of surface charge on the adsorption of Ag NP onto soil particles, bare and citrate-stabilized Ag NP, differing in the zeta potential, were equilibrated with silt at a solid-to-solution ratio of 1:10 and an initial Ag concentration range of 30 to 320 μg/L. Results showed that bare Ag NPs sorb organic matter, with short-chained organic matter being preferentially adsorbed over long-chained, aromatic organic matter. Stabilizing effects of organic matter only come into play at higher Ag NP concentrations. Soil solution inhibits the release of Ag ions, presumably due to organic matter coatings. Sorption to silt particles was very similar for the two particle types, suggesting that the surface charge does not control Ag NP sorption. Besides, sorption was much lower than in comparable studies with sand and glass surfaces.
    Keywords: Isoelectric Point ; Cation Valency ; Initial Nanoparticle Concentration ; Exchangeability of Sorbed Ag Ions ; Environmental Sciences ; Biology ; Public Health
    ISSN: 0048-9697
    E-ISSN: 1879-1026
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Language: English
    In: Science of the Total Environment, 01 December 2015, Vol.535, pp.1-2
    Keywords: Environmental Sciences ; Biology ; Public Health
    ISSN: 0048-9697
    E-ISSN: 1879-1026
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Language: English
    In: Science of the Total Environment, 01 December 2015, Vol.535, pp.3-19
    Description: Engineered inorganic nanoparticles (EINP) from consumers' products and industrial applications, especially silver and titanium dioxide nanoparticles (NP), are emitted into the aquatic and terrestrial environments in increasing amounts. However, the current knowledge on their environmental fate and biological effects is diverse and renders reliable predictions complicated. This review critically evaluates existing knowledge on colloidal aging mechanisms, biological functioning and transport of Ag NP and TiO NP in water and soil and it discusses challenges for concepts, experimental approaches and analytical methods in order to obtain a comprehensive understanding of the processes linking NP fate and effects. Ag NP undergo dissolution and oxidation with Ag S as a thermodynamically determined endpoint. Nonetheless, Ag NP also undergo colloidal transformations in the nanoparticulate state and may act as carriers for other substances. Ag NP and TiO NP can have adverse biological effects on organisms. Whereas Ag NP reveal higher colloidal stability and mobility, the efficiency of NOM as a stabilizing agent is greater towards TiO NP than towards Ag NP, and multivalent cations can dominate the colloidal behavior over NOM. Many of the past analytical obstacles have been overcome just recently. Single particle ICP-MS based methods in combination with field flow fractionation techniques and hydrodynamic chromatography have the potential to fill the gaps currently hampering a comprehensive understanding of fate and effects also at a low field relevant concentrations. These analytical developments will allow for mechanistically orientated research and transfer to a larger set of EINP. This includes separating processes driven by NP specific properties and bulk chemical properties, categorization of effect-triggering pathways directing the EINP effects towards specific recipients, and identification of dominant environmental parameters triggering fate and effect of EINP in specific ecosystems (e.g. soil, lake, or riverine systems).
    Keywords: Transport ; Aggregation ; Analytics ; Environment ; Aging ; Ecotoxicology ; Environmental Sciences ; Biology ; Public Health
    ISSN: 0048-9697
    E-ISSN: 1879-1026
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Language: English
    In: Science of the Total Environment, 15 December 2018, Vol.645, pp.192-204
    Description: Riverbank filtration systems are important structures that ensure the cleaning of infiltrating surface water for drinking water production. In our study, we investigated the potential risk for a breakthrough of environmentally aged silver nanoparticles (Ag NP) through these systems. Additionally, we identified factors leading to the remobilization of Ag NP accumulated in surficial sediment layers in order to gain insights into remobilization mechanisms. We conducted column experiments with Ag NP in an outdoor pilot plant consisting of water-saturated sediment columns mimicking a riverbank filtration system. The NP had previously been aged in river water, soil extract, and ultrapure water, respectively. We investigated the depth-dependent breakthrough and retention of NP. In subsequent batch experiments, we studied the processes responsible for a remobilization of Ag NP retained in the upper 10 cm of the sediments, induced by ionic strength reduction, natural organic matter (NOM), and mechanical forces. We determined the amount of remobilized Ag by ICP-MS and differentiated between particulate and ionic Ag after remobilization using GFAAS. The presence of Ag-containing heteroaggregates was investigated by combining filtration with single-particle ICP-MS. Single and erratic Ag breakthrough events were mainly found in 30 cm depth and Ag NP were accumulated in the upper 20 cm of the columns. Soil-aged Ag NP showed the lowest retention of only 54%. Remobilization was induced by the reduction of ionic strength and the presence of NOM in combination with mechanical forces. The presence of calcium in the aging- as well as the remobilizing media reduced the remobilization potential. Silver NP were mainly remobilized as heteroaggregates with natural colloids, while dissolution played a minor role. Our study indicates that the breakthrough potential of Ag NP in riverbank filtration systems is generally low, but the aging in soil increases their mobility. Remobilization processes are associated to co-mobilization with natural colloids.
    Keywords: Heteroaggregation ; Nanoparticle Transformation ; Breakthrough ; Mobility ; Reversibility ; Environmental Sciences ; Biology ; Public Health
    ISSN: 0048-9697
    E-ISSN: 1879-1026
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    In: Environmental Microbiology, June 2016, Vol.18(6), pp.1988-2000
    Description: Phosphorus () is an important macronutrient for all biota on earth but similarly a finite resource. Microorganisms play on both sides of the fence as they effectively mineralize organic and solubilize precipitated forms of soil phosphorus but conversely also take up and immobilize . Therefore, we analysed the role of microbes in two beech forest soils with high and low content by direct sequencing of metagenomic deoxyribonucleic acid. For inorganic solubilization, a significantly higher microbial potential was detected in the ‐rich soil. This trait especially referred to  olibacter usiatus, likewise one of the dominating species in the data sets. A higher microbial potential for efficient phosphate uptake systems () was detected in the ‐depleted soil. Genes involved in starvation response regulation (, ) were prevalent in both soils. This underlines the importance of effective phosphate (ho) regulon control for microorganisms to use alternative sources during phosphate limitation. Predicted genes were primarily harboured by hizobiales, ctinomycetales and cidobacteriales.
    Keywords: Soil Microbiology – Analysis ; Nucleic Acids – Analysis ; Phosphates – Analysis ; Forest Soils – Analysis ; Soil Phosphorus – Analysis;
    ISSN: 1462-2912
    E-ISSN: 1462-2920
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    In: Environmental Microbiology, September 2016, Vol.18(8), pp.2767-2767
    Description: Byline: Fabian Bergkemper, Anne Scholer, Marion Engel, Friederike Lang, Jaane Kruger, Michael Schloter, Stefanie Schulz ***** No abstract is available for this article. *****
    Keywords: Recycling ; Forest Soils ; Soil Microbiology;
    ISSN: 1462-2912
    E-ISSN: 1462-2920
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Language: English
    In: Journal of Microbiological Methods, June 2016, Vol.125, pp.91-97
    Description: Phosphorus (P) is of central importance for cellular life but likewise a limiting macronutrient in numerous environments. Certainly microorganisms have proven their ability to increase the phosphorus bioavailability by mineralization of organic-P and solubilization of inorganic-P. On the other hand they efficiently take up P and compete with other biota for phosphorus. However the actual microbial community that is associated to the turnover of this crucial macronutrient in different ecosystems remains largely anonymous especially taking effects of seasonality and spatial heterogeneity into account. In this study seven oligonucleotide primers are presented which target genes coding for microbial acid and alkaline phosphatases ( , ), phytases ( ), phosphonatases ( ) as well as the quinoprotein glucose dehydrogenase ( ) and different P transporters ( , ). Illumina amplicon sequencing of soil genomic DNA underlined the high rate of primer specificity towards the respective target gene which usually ranged between 98% and 100% ( : 87%). As expected the primers amplified genes from a broad diversity of distinct microorganisms. Using DNA from a beech dominated forest soil, the highest microbial diversity was detected for the alkaline phosphatase ( ) gene which was amplified from 15 distinct phyla respectively 81 families. Noteworthy the primers also allowed amplification of from 6 fungal orders. The genes coding for acid phosphatase ( ) and the quinoprotein glucose dehydrogenase ( ) were amplified from 20 respectively 17 different microbial orders. In comparison the phytase and phosphonatase ( , ) primers covered 13 bacterial orders from 2 different phyla respectively. Although the amplified microbial diversity was apparently limited both primers reliably detected all orders that contributed to the P turnover in the investigated soil as revealed by a previous metagenomic approach. Genes that code for microbial P transporter ( , ) were amplified from 13 respectively 9 distinct microbial orders. Accordingly the introduced primers represent a valuable tool for further analysis of the microbial community involved in the turnover of phosphorus in soils but most likely also in other environments.
    Keywords: Phosphorus Turnover ; Forest Soil ; Phod ; Phon ; Appa ; Pita ; Psts ; Biology
    ISSN: 0167-7012
    E-ISSN: 1872-8359
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. Further information can be found on the KOBV privacy pages