Suchergebnisse

Intro -- Effect-Directed Analysis of Complex Environmental Contamination -- Series Preface -- Volume Preface -- Acknowledgments -- Contents -- Early Evolution of the Toxicity Identification Evaluation Process: Contributions from the United States Environmental Protecti -- Recent Developments in Whole Sediment Toxicity Identification Evaluations: Innovations in Manipulations and Endpoints -- Considerations for Incorporating Bioavailability in Effect-Directed Analysis and Toxicity Identification Evaluation -- Diagnostic Tools for Effect-Directed Analysis of Mutagens, AhR Agonists, and Endocrine Disruptors -- Separation Techniques in Effect-Directed Analysis -- Simultaneous Screening and Chemical Characterization of Bioactive Compounds Using LC-MS-Based Technologies (Affinity Chromatog -- Advanced GC-MS and LC-MS Tools for Structure Elucidation in Effect-Directed Analysis -- Computer Tools for Structure Elucidation in Effect-Directed Analysis -- Effect-Directed Analysis of Mutagens in Ambient Airborne Particles -- Effect-Directed Analysis of Endocrine Disruptors in Aquatic Ecosystems -- Effects-Directed Studies of Pulp and Paper Mill Effluents -- Effect-Directed Analysis of Ah-Receptor Mediated Toxicants, Mutagens, and Endocrine Disruptors in Sediments and Biota -- Ecological Relevance of Key Toxicants in Aquatic Systems -- Index.

Abstract
Background
In surface waters, using liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS), typically large numbers of chemical signals often with high peak intensity remain unidentified. These chemical signals may represent natural compounds released from plants, animals and microorganisms, which may contribute to the cumulative toxic risk. Thus, attempts were made to identify natural compounds in significant concentrations in surface waters by identifying overlapping LC-HRMS peaks between extracts of plants abundant in the catchment and river waters using a non-target screening (NTS) work flow.

Results
The result revealed the presence of several thousands of overlapping peaks between water—and plants from local vegetation. Taking this overlap as a basis, 12 SPMs from different compound classes were identified to occur in river waters with flavonoids as a dominant group. The concentrations of the identified compounds ranged from 0.02 to 5 µg/L with apiin, hyperoside and guanosine with highest concentrations. Most of the identified compounds exceeded the threshold for toxicological concern (TTC) (0.1 µg/L) for non-genotoxic and non-endocrine disrupting chemicals in drinking water often by more than one order of magnitude.

Conclusion
Our results revealed the contribution of chemicals eluted from the vegetation in the catchment to the chemical load in surface waters and help to reduce the number of unknowns among NTS high-intensity peaks detected in rivers. Since secondary plant metabolites (SPMs) are often produced for defence against other organisms and since concentrations ranges are clearly above TTC a contribution to toxic risks on aquatic organisms and impacts on drinking water safety cannot be excluded. This demands for including these compounds into monitoring and assessment of water quality.

AbstractIntroduction: Restriction factors (RFs) suppress HIV‐1 in cell lines and primary cell models. Hence, RFs might be attractive targets for novel antiviral strategies, but their importance for virus control in vivo is controversial.Methods: We profiled the expression of RFs in primary blood‐derived mononuclear cells (PBMC) from therapy‐naïve HIV‐1 patients and quantified infection.Results: Overall, there was no correlation between individual RF expression and HIV‐1 status in total PBMC. However, we identified a T cell population with low levels of intracellular CD2 and reduced expression of SAMHD1, p21 and SerinC5. CD2low T cells with reduced RF expression were markedly positive for HIV‐1 p24. In contrast, CD2+ T cells were less infected and expressed higher levels of RFs. CD2low T cell infection correlated with viral loads and was associated with HIV‐1 disease progression.Conclusions: In untreated therapy naïve chronic HIV‐1 patients, RF expression in T cells is associated with CD2 expression and seems to influence viral loads. Our study suggests that RFs help to control HIV‐1 infection in certain T cells in vivo and supports the potential for RFs as promising targets for therapeutic intervention.

AbstractBackgroundChemical pollution forms a severe threat for human and environmental health. While the risks for European lowland water bodies are well known, there is little knowledge on remote aquatic ecosystems and particularly mountain lakes, despite their importance for the provision of freshwater. Here, we critically review the current knowledge on the exposure and risk by chemical pollution for mountain lakes and present a tiered approach on how to advance effectively our understanding in the future.ResultsGenerally, pollutant monitoring data are currently incomplete, with many regions and substances having been only poorly investigated. More reliable data exist only for persistent organic pollutants (POPs). However, there is increasing evidence that even remote mountain lakes are exposed to a wide range of organic pollutants. Among them potent pesticides currently used in agricultural and biocidal applications, such as diazinon and permethrin. The exposure of mountain lakes to pollutants follows a complex pattern. Pollutants are introduced into mountain lakes via the atmospheric deposition and run-off from the watershed, but also local sources, like tourism and pastoralism. Our risk assessment and recent biomonitoring studies suggest that there are widespread chronic toxic risks on crustacean in mountain ranges. If mountain ranges are exposed to tourism and pastoralism, even acute toxic effects on crustacean are possible. Thereby, the vulnerability of mountain lakes to toxic effects has to be expected to be particularly high due to the harsh environmental conditions at high altitudes, the organism's traits, the insular position of mountain lakes and a lower species richness with increasing altitudes. Furthermore, there is little knowledge on the biological processes leading to the degradation of chemical pollutants under the environmental and ecological conditions of mountain ecosystems.ConclusionWhile the exposure and sensitivity of mountain aquatic ecosystems is currently poorly investigated, the existing data suggest that it is very likely that also water bodies as remote as mountain lakes do suffer from pollution-induced toxicity. To verify this suggestion and expand the existing knowledge, it is necessary that future studies combine a more holistic pollution monitoring with exposure modelling and links to biological effects. Only then will it be possible to obtain a more reliable understanding of the impact of chemical pollution on aquatic mountain ecosystems and to protect these fragile ecosystems.

Abstract
Robust techniques based on liquid (LC) and gas chromatography (GC) coupled with high-resolution mass spectrometry (HR-MS) enable sensitive screening, identification, and (semi)quantification of thousands of substances in a single sample. Recent progress in computational sciences has enabled archiving and processing of HR-MS 'big data' at the routine level. As a result, community-based databases containing thousands of environmental pollutants are rapidly growing and large databases of substances with unique identifiers allowing for inter-comparison at the global scale have become available. A data-archiving infrastructure is proposed, allowing for retrospective screening of HR-MS data, which will help define the 'chemical universe' of organic substances and enable prioritisation of toxicants causing adverse environmental effects at the local, river basin, and national and European scale in support of the European water and chemicals management policy.