SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Keiter Steffen) "

Sökning: WFRF:(Keiter Steffen)

  • Resultat 1-50 av 68
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Keiter, Susanne, et al. (författare)
  • Does perfluorooctane sulfonate (PFOS) act as chemosensitizer in zebrafish embryos?
  • 2016
  • Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 548-549, s. 317-324
  • Tidskriftsartikel (refereegranskat)abstract
    • Earlier studies have shown that perfluorooctane sulfonate (PFOS) increases the toxicity of other chemicals by enhancing their uptake by cells and tissues. The present study aimed at testing whether the underlying mechanism of enhanced uptake of chemicals by zebrafish (Danio rerio) embryos in the presence of PFOS is by interference of this compound with the cellular efflux transporter Abcb4. Modifications of uptake/clearance and toxicity of two Abcb4 substrates, the fluorescent dye rhodamine B (RhB) and vinblastine, by PFOS were evaluated using 24 and 48. h post-fertilization (hpf) embryos. Upon 90. min exposure of 24. hpf embryos to 1. μM RhB and different PFOS concentrations (3-300. μM) accumulation of RhB in zebrafish was increased by up to 11.9-fold compared to controls, whereas RhB increases in verapamil treatments were 1.7-fold. Co-administration of PFOS and vinblastine in exposures from 0 to 48. hpf resulted in higher vinblastine-caused mortalities in zebrafish embryos indicating increased uptake of this compound. Interference of PFOS with zebrafish Abcb4 activity was further studied using recombinant protein obtained with the baculovirus expression system. PFOS lead to a concentration-dependent decrease of the verapamil-stimulated Abcb4 ATPase activity; at higher PFOS concentrations (250, 500. μM), also the basal ATPase activity was lowered indicating PFOS to be an Abcb4 inhibitor. In exposures of 48. hpf embryos to a very high RhB concentration (200. μM), accumulation of RhB in embryo tissue and adsorption to the chorion were increased in the presence of 50 or 100. μM PFOS. In conclusion, the results indicate that PFOS acts as inhibitor of zebrafish Abcb4; however, the exceptionally large PFOS-caused effect amplitude of RhB accumulation in the 1. μM RhB experiments and the clear PFOS effects in the experiments with 200. μM RhB suggest that an additional mechanism appears to be responsible for the potential of PFOS to enhance uptake of Abcb4 substrates.
  •  
2.
  • Otte, Jens, et al. (författare)
  • Contribution of Priority PAHs and POPs to Ah Receptor-Mediated Activities in Sediment Samples from the RiverElbe Estuary, Germany
  • 2013
  • Ingår i: PLOS ONE. - San Francisco, USA : Public Library Service. - 1932-6203. ; 8:10
  • Tidskriftsartikel (refereegranskat)abstract
    • The estuary of the River Elbe between Hamburg and the North Sea (Germany) is a sink for contaminated sediment and suspended particulate matter (SPM). One major concern is the effect of human activities on the hydrodynamics, particularlythe intensive dredging activities in this area that may result in remobilization of sediment-bound pollutants. The aim of this study was to identify pollutants contributing to the toxicological risk associated with re-suspension of sediments in the Elbe Estuary by use of an effect-directed analysis that combines chemical and biological analyses in with specific fractionation techniques. Sediments were collected from sites along the Elbe Estuary and a site from a small harbor basin of the Elbe Estuary that is known to be polluted. The sixteen priority EPA-PAHs were quantified in organic extracts of sediments. In addition, dioxin equivalents of sediments were investigated by use of the 7-ethoxyresorufin O-deethylase assay with RTL-W1 cells and the Ah receptor-mediated luciferase transactivation assay with H4IIE-luc cells. Quantification of the 16 priorityPAHs revealed that sediments were moderately contaminated at all of the sites in the Elbe River Estuary (,0.02–0.906 mg/gdw). Sediments contained relatively small concentrations of dioxin equivalents (Bio-TEQ) with concentrations ranging from15.5 to 322 pg/g dw, which were significantly correlated with dioxin equivalents calculated based on toxicity referencevalues and concentrations of PAH. The concentration of Bio-TEQ at the reference site exceeded 200,000 pg/g dw. In apotency balance the 16 PAHs explained between 47 and 118% of the Bio-TEQ in the luciferase assay, which can be explained by the constant input of PAHs bound to SPM from the upper course of the Elbe River into its estuary. Successful identification of a significant portion of dioxin-like activity to priority PAHs in complex environmental samples such assediments has rarely been reported.
  •  
3.
  • Alfonso, Sébastien, et al. (författare)
  • Examining multi- and transgenerational behavioral and molecular alterations resulting from parental exposure to an environmental PCB and PBDE mixture
  • 2019
  • Ingår i: Aquatic Toxicology. - : Elsevier. - 0166-445X .- 1879-1514. ; 208, s. 29-38
  • Tidskriftsartikel (refereegranskat)abstract
    • Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are persistent organic pollutants extensively used during the 20th century and still present in aquatic environments despite their ban. Effects of exposure to these compounds over generations are poorly documented. Therefore, our aims were to characterize behavioral responses and underlying molecular mechanisms in zebrafish exposed to an environmentally relevant mixture of PCBs and PBDEs as well as in four unexposed offspring generations. Zebrafish (F0) were chronically exposed from the first meal onward to a diet spiked with a mixture containing 22 PCB and 7 PBDE congeners in proportions and concentrations reflecting environmental situations (ΣPCBs = 1991 and ΣPBDEs = 411 ng/g). Four offspring generations (F1 to F4) were obtained from this F0 and were not further exposed. Behavior was assessed at both larval and adult stages. Mechanisms related to behavioral defects (habenula maturation and c-fos transcription) and methylation (dnmts transcription) were monitored in larvae. Exposed adult F0 as well as F1 and F3 adults displayed no behavioral change while F2 expressed anxiety-like behavior. Larval behavior was also disrupted, i.e. hyperactive after light to dark transition in F1 or hypoactive in F2, F3 and F4. Behavioral disruptions may be related to defect in habenula maturation (observed in F1) and change in c-fos transcription (observed in F1 and F2). Transcription of the gene encoding DNA methyltransferase (dnmt3ba) was also modified in all generations. Our results lead us to hypothesize that chronic dietary exposure to an environmentally relevant mixture of PCB and PBDE triggers multigenerational and transgenerational molecular and behavioral disruptions in a vertebrate model.
  •  
4.
  • Batel, A., et al. (författare)
  • Histological, enzymatic and chemical analyses of the potential effects of differently sized microplastic particles upon long-term ingestion in zebrafish (Danio rerio)
  • 2020
  • Ingår i: Marine Pollution Bulletin. - : Elsevier. - 0025-326X .- 1879-3363. ; 153
  • Tidskriftsartikel (refereegranskat)abstract
    • In microplastics (MPs) research, there is an urgent need to critically reconsider methodological approaches and results published, since public opinion and political decisions might be based on studies using debatable methods and reporting questionable results. For instance, recent studies claim that MPs induce intestinal damage and that relatively large MPs are transferred to, e.g., livers in fish. However, there is methodological criticism and considerable concern whether MP transfer to surrounding tissues is plausible. Likewise, there is an ongoing discussion in MP research if MPs act as vectors for adsorbed hazardous chemicals. In this study, effects of very small (4–6 μm) and very large (125–500 μm) benzo(a) pyrene (BaP)-spiked polyethylene (PE) particles administered via different uptake routes (food chain vs. direct uptake) were compared in a 21-day zebrafish (Danio rerio) feeding experiment. Particular care was taken to prevent cross-contamination of MPs during dissection and histological sample preparation. In contrast to numerous reports in literature describing similar approaches, independent of exposure route and MP size, no adverse effects could be detected. Likewise, no BaP accumulation could be documented, and MPs were exclusively seen in the lumen of the intestinal tract, which, however, did not induce any histopathological effects. Results indicate that in fish MPs are taken up, pass along the intestinal lumen and are excreted without any symptoms of adverse effects.
  •  
5.
  • Beiras, R., et al. (författare)
  • Ingestion and contact with polyethylene microplastics does not cause acute toxicity on marine zooplankton
  • 2018
  • Ingår i: Journal of Hazardous Materials. - : Elsevier. - 0304-3894 .- 1873-3336. ; 360, s. 452-460
  • Tidskriftsartikel (refereegranskat)abstract
    • Toxicity of polyethylene microplastics (PE-MP) of size ranges similar to their natural food to zooplanktonic organisms representative of the main taxa present in marine plankton, including rotifers, copepods, bivalves, echinoderms and fish, was evaluated. Early life stages (ELS) were prioritized as testing models in order to maximize sensitivity. Treatments included particles spiked with benzophenone-3 (BP-3), a hydrophobic organic chemical used in cosmetics with direct input in coastal areas. Despite documented ingestion of both virgin and BP-3 spiked microplastics no acute toxicity was found at loads orders of magnitude above environmentally relevant concentrations on any of the invertebrate models. In fish tests some effects, including premature or reduced hatching, were observed after 12 d exposure at 10 mg L-1 of BP-3 spiked PE-MP. The results obtained do not support environmentally relevant risk of microplastics on marine zooplankton. Similar approaches testing more hydrophobic chemicals with higher acute toxicity are needed before these conclusions could be extended to other organic pollutants common in marine ecosystems. Therefore, the replacement of these polymers in consumer products must be carefully considered.
  •  
6.
  •  
7.
  • Blanc, Mélanie, 1993-, et al. (författare)
  • An environmentally relevant mixture of polychlorinated biphenyls (PCBs) and polybrominated diphenylethers (PBDEs) disrupts mitochondrial function, lipid metabolism and neurotransmission in the brain of exposed zebrafish and their unexposed F2 offspring
  • 2021
  • Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 754
  • Tidskriftsartikel (refereegranskat)abstract
    • Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are persistent organic pollutants still present in aquatic environments despite their total or partial ban. Previously, we observed that an environmentally realistic mixture of these compounds affects energy balance, growth, and reproduction in exposed zebrafish (F0), and behavior in their unexposed offspring (F1-F4). In the present work, we performed lipidomic and transcriptomic analyses on brains of zebrafish (F0-F2) from exposed and control lineages to identify molecular changes that could explain the observed phenotypes. The use of both technologies highlighted that F0 zebrafish displayed impaired mitochondrial function and lipid metabolism regulation (depletion in triacylglycerols and phospholipids) which can explain disruption of energy homeostasis. A subset of the regulated biological pathways related to energetic metabolism and neurotransmission were inherited in 12. In addition, there were increasing effects on epigenetic pathways from the F0 to the F2 generation. Altogether, we show that the effects of an environmental exposure to PCBs and PBDEs on energetic metabolism as well as neurotransmission extend over 2 generations of zebrafish, possibly due to transgenerational epigenetic inheritance.
  •  
8.
  • Blanc, Mélanie, 1993-, et al. (författare)
  • Environmental chemicals differentially affect epigenetic-related mechanisms in the zebrafish liver (ZF-L) cell line and in zebrafish embryos
  • 2019
  • Ingår i: Aquatic Toxicology. - : Elsevier. - 0166-445X .- 1879-1514. ; 215
  • Tidskriftsartikel (refereegranskat)abstract
    • A number of chemicals have been shown to affect epigenetic patterning and functions. Since epigenetic mechanisms regulate transcriptional networks, epigenetic changes induced by chemical exposure can represent early molecular events for long-term adverse physiological effects. Epigenetics has thus appeared as a research field of major interest within (eco)toxicological sciences. The present study aimed at measuring effects on epigenetic-related mechanisms of selected environmental chemicals (bisphenols, perfluorinated chemicals, methoxychlor, permethrin, vinclozolin and coumarin 47) in zebrafish embryos and liver cells (ZFL). Transcription of genes related to DNA methylation and histone modifications was measured and global DNA methylation was assessed in ZFL cells using the LUMA assay. The differences in results gathered from both models suggest that chemicals affect different mechanisms related to epigenetics in embryos and cells. In zebrafish embryos, exposure to bisphenol A, coumarin 47, methoxychlor and permethrin lead to significant transcriptional changes in epigenetic factors suggesting that they can impact early epigenome reprogramming related to embryonic development. In ZFL cells, significant transcriptional changes were observed upon exposure to all chemicals but coumarin 47; however, only perfluorooctane sulfonate induced significant effects on global DNA methylation. Notably, in contrast to the other tested chemicals, perfluorooctane sulfonate affected only the expression of the histone demethylase kdm5ba. In addition, kdm5ba appeared as a sensitive gene in zebrafish embryos as well. Taken together, the present results suggest a role for kdm5ba in regulating epigenetic patterns in response to chemical exposure, even though mechanisms remain unclear. To confirm these findings, further evidence is required regarding changes in site-specific histone marks and DNA methylation together with their long-term effects on physiological outcomes.
  •  
9.
  • Blanc, Mélanie, 1993- (författare)
  • How can an organism´s life experience affect their descendants? Insights from epigenetic and transgenerational effects of chemical exposure in zebrafish
  • 2020
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Environmental pollution causes approx. 10% of human diseases, and some develop in the progeny because of parental exposure. Effects passed on to subsequent generations may be a consequence of genetic mutations, or of inherited changes in epigenetic patterns. Epigenetics is the study of mitotically or meiotically heritable changes in gene function that cannot be explained by changes in the DNA sequence. Several chemicals have been suggested to induce epigenetic dysregulation leading to multigenerational and transgenerational effects, i.e. effects that can be observed in completely unexposed generations. However, mechanisms underlying the inheritance of epigenetic changes and their implication in phenotypic adversities are complex and not well-understood. The overall aim of this thesis was to study adverse effects and underlying molecular changes in several generations of zebrafish after parental exposure to selected industrial chemicals. To this end, molecular (lipidomic, transcriptomic, epigenomic) and behavioral analyses were performed. Zebrafish is an acknowledged model for vertebrates in toxicology and biomedicine; as such, the findings can be relevant to many organisms including human. The results from this thesis showed that different types of chemicals, polychlorinated biphenyls, polybromodiphenyl ethers, and permethrin, induced transgenerational effects in concentrations relevant to environmental or human exposures. Impact on anxiety and locomotor activity of zebrafish was observed over several generations. Gene expression and epigenetic (DNA methylation) alterations were partly inherited and suggest stable alteration of specific functions such as glutamatergic/GABAergic neurotransmission and synaptic plasticity. Finally, the findings shed light on experimental limitations and research perspectives, which we expect will contribute to the design of future studies on epigenetically inherited effects of any environmental stress.
  •  
10.
  • Blanc, Mélanie, 1993-, et al. (författare)
  • Mixture-specific gene expression in zebrafish (Danio rerio) embryos exposed to perfluorooctane sulfonic acid (PFOS), perfluorohexanoic acid (PFHxA) and 3,3′,4,4′,5-pentachlorobiphenyl (PCB126)
  • 2017
  • Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 590-591, s. 249-257
  • Tidskriftsartikel (refereegranskat)abstract
    • Perfluorooctane sulfonic acid (PFOS) and 3,3′,4,4′,5-pentachlorobiphenyl (PCB126) are persistent organic pollutants of high concern because of their environmental persistence, bioaccumulation and toxic properties. Besides, the amphiphilic properties of fluorinated compounds such as PFOS and perfluorohexanoic acid (PFHxA) suggest a role in increasing cell membrane permeability and solubilizing chemicals. The present study aimed at investigating whether PFOS and PFHxA are capable of modifying the activation of PCB126 toxicity-related pathways. For this purpose, zebrafish embryos were exposed in semi-static conditions to 7.5 μg/L of PCB126 alone, in the presence of 25 mg/L of PFOS, 15.7 mg/L of PFHxA or in the presence of both PFOS and PFHxA. Quantitative PCR was performed on embryos aged from 24 h post fertilization (hpf) to 96 hpf to investigate expression changes of genes involved in metabolism of xenobiotics (ahr2, cyp1a), oxidative stress (gpx1a, tp53), lipids metabolism (acaa2, osbpl1a), and epigenetic mechanisms (dnmt1, dnmt3ba). Cyp1a and ahr2 expression were significantly induced by the presence of PCB126. However, after 72 and 78 h of exposure, induction of cyp1a expression was significantly lower when embryos were co-exposed to PCB126 + PFOS + PFHxA when compared to PCB126-exposed embryos. Significant upregulation of gpx1a occurred after exposure to PCB126 + PFHxA and to PCB126 + PFOS + PFHxA at 30 and 48 hpf. Besides, embryos appeared more sensitive to PCB126 + PFOS + PFHxA at 78 hpf: acaa2 and osbpl1a were significantly downregulated; dnmt1 was significantly upregulated. While presented as environmentally safe, PFHxA demonstrated that it could affect gene expression patterns in zebrafish embryos when combined to PFOS and PCB126, suggesting that such mixture may increase PCB126 toxicity. This is of particular relevance since PFHxA is persistent and still being ejected into the environment. Moreover, it provides additional information as to the importance to integrate mixture effects of chemicals in risk assessment and biomonitoring frameworks.
  •  
11.
  •  
12.
  • Blanc, Mélanie, 1993-, et al. (författare)
  • Multi- and transgenerational effects following early-life exposure of zebrafish to permethrin and coumarin 47 : Impact on growth, fertility, behavior and lipid metabolism
  • 2020
  • Ingår i: Ecotoxicology and Environmental Safety. - : Academic Press. - 0147-6513 .- 1090-2414. ; 205
  • Tidskriftsartikel (refereegranskat)abstract
    • Transgenerational effects induced by environmental stressors are a threat to ecosystems and human health. However, there is still limited observation and understanding of the potential of chemicals to influence life outcomes over several generations. In the present study, we investigated the effects of two environmental contaminants, coumarin 47 and permethrin, on exposed zebrafish (FO) and their progeny (F1-F3). Coumarin 47 is commonly found in personal care products and dyes, whereas permethrin is used as a domestic and agricultural pyrethroid insecticide/insect repellent. Zebrafish (F0) were exposed during early development until 28 days post-fertilization and their progeny (F1-F3) were bred unexposed. On one hand, the effects induced by coumarin 47 suggest no multigenerational toxicity. On the other hand, we found that behavior of zebrafish larvae was significantly affected by exposure to permethrin in F1 to F3 generations with some differences depending on the concentration. This suggests persistent alteration of the neural or neuromuscular function. In addition, lipidomic analyses showed that permethrin treatment was partially correlated with lysophosphatidylcholine levels in zebrafish, an important lipid for neurodevelopment. Overall, these results stress out one of the most widely used pyrethroids can trigger long-term, multi- and possibly transgenerational changes in the nervous system of zebrafish. These neurobehavioral changes echo the effects observed under direct exposure to high concentrations of permethrin and therefore call for more research on mechanisms underlying effect inheritance.
  •  
13.
  • Blanc, Mélanie, 1993-, et al. (författare)
  • The insecticide permethrin induces transgenerational behavioral changes linked to transcriptomic and epigenetic alterations in zebrafish (Danio rerio)
  • 2021
  • Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 779
  • Tidskriftsartikel (refereegranskat)abstract
    • The pyrethroid insecticide permethrin is widely used for agricultural and domestic purposes. Previous data indicated that it acts as a developmental neurotoxicant and can induce transgenerational effects in non-target organisms. However, associated underlying mechanisms remain unclear. The aim of this study was to investigate permethrin-related transgenerational effects in the zebrafish model, and to identify possible molecular mechanisms underlying inheritance. Zebrafish (F0) were exposed to permethrin during early-life (2 h post-fertilization up to 28 days). The F1 and F2 offspring generations were obtained by pairing exposed F0 males and females, and were bred unexposed. Locomotor and anxiety behavior were investigated, together with transcriptomic and epigenomic (DNA methylation) changes in brains. Permethrin exposed F0 fish were hypoactive at adulthood, while males from the F1 and F2 generations showed a specific decrease in anxiety-like behavior. In F0, transcriptomic data showed enrichment in pathways related to glutamatergic synapse activity, which may partly underlie the behavioral effects. In F1 and F2 males, dysregulation of similar pathways was observed, including a subset of differentially methylated regions that were inherited from the F0 to the F2 generation and indicated stable dysregulation of glutamatergic signaling. Altogether, the present results provide novel evidence on the transgenerational neurotoxic effects of permethrin, as well as mechanistic insight: a transient exposure induces persistent transcriptional and DNA methylation changes that may translate into transgenerational alteration of glutamatergic signaling and, thus, into behavioral alterations.
  •  
14.
  •  
15.
  • Bluhm, Kerstin, et al. (författare)
  • Impacts of Different Exposure Scenarios on Transcript Abundances in Danio rerio Embryos when Investigating the Toxicological Burden of Riverine Sediments
  • 2014
  • Ingår i: PLOS ONE. - San francisco, USA : Public Library of Science. - 1932-6203. ; 9:9
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: Recently, a proof-of-concept study revealed the suitability of transcriptome analyses to obtain and assess changes in the abundance of transcripts in zebrafish (Danio rerio) embryos after exposure to organic sediment extracts. The present study investigated changes in the transcript abundance in zebrafish embryos exposed to whole sediment samples and corresponding organic extracts in order to identify the impact of different exposure pathways on sediment toxicity.Materials and Methods: Danio rerio embryos were exposed to sublethal concentrations of three sediment samples from the Danube River, Germany. The sediment samples were investigated both as freeze-dried samples and as organic extracts. Silica dust and a process control of the extraction procedure were used as references. After exposure, mRNA was isolated and changes in profiles of gene expression levels were examined by an oligonucleotide microarray. The microarray results were compared with bioassays, chemical analysis of the sediments and profiles of gene expression levels induced by several single substances.Results and Discussion: The microarray approach elucidated significant changes in the abundance of transcripts in exposed zebrafish embryos compared to the references. Generally, results could be related to Ah-receptor-mediated effects asconfirmed by bioassays and chemical analysis of dioxin-like contaminants, as well as to exposure to stress-inducing compounds. Furthermore, the results indicated that mixtures of chemicals, as present in sediment and extract samples, result in complex changes of gene expression level profiles difficult to compare with profiles induced by single chemical substances. Specifically, patterns of transcript abundances were less influenced by the chemical composition at the sampling site compared t the method of exposure (sediment/extract). This effect might be related to different bioavailability of chemicals.Conclusions: The apparent difference between the exposure scenarios is an important aspect that needs to be addressed when conducting analyses of alterations in the expression level of mRNA.
  •  
16.
  • Bour, Agathe, et al. (författare)
  • Environmentally relevant microplastic exposure affects sediment-dwelling bivalves
  • 2018
  • Ingår i: Environmental Pollution. - : Elsevier. - 0269-7491 .- 1873-6424. ; 236, s. 652-660
  • Tidskriftsartikel (refereegranskat)abstract
    • Most microplastics are expected to sink and end up in marine sediments. However, very little is known concerning their potential impact on sediment-dwelling organisms. We studied the long-term impact of microplastic exposure on two sediment-dwelling bivalve species. Ennucula tenuis and Abra nitida were exposed to polyethylene microparticles at three concentrations (1; 10 and 25 mg/kg of sediment) for four weeks. Three size classes (4-6; 20-25 and 125-500 mu m) were used to study the influence of size on microplastic ecotoxicity. Microplastic exposure did not affect survival, condition index or burrowing behaviour in either bivalve species. However, significant changes in energy reserves were observed. No changes were observed in protein, carbohydrate or lipid contents in E. tenuis, with the exception of a decrease in lipid content for one condition. However, total energy decreased in a dose-dependent manner for bivalves exposed to the largest particles. To the contrary, no significant changes in total energy were observed for A. nitida, although a significant decrease of protein content was observed for individuals exposed to the largest particles, at all concentrations. Concentration and particle size significantly influenced microplastic impacts on bivalves, the largest particles and higher concentrations leading to more severe effects. Several hypotheses are presented to explain the observed modulation of energy reserves, including the influence of microplastic size and concentration. Our results suggest that long-term exposure to microplastics at environmentally relevant concentrations can impact marine benthic biota.
  •  
17.
  • Bräunig, Jennifer, et al. (författare)
  • Time-dependent expression and activity of cytochrome P450 1s in early life-stages of the zebrafish (Danio rerio)
  • 2015
  • Ingår i: Environmental Science and Pollution Research. - : Springer. - 0944-1344 .- 1614-7499. ; 22:21, s. 16319-15328
  • Tidskriftsartikel (refereegranskat)abstract
    • Zebrafish embryos are being increasingly used as model organisms for the assessment of single substances and complex environmental samples for regulatory purposes.Thus, it is essential to fully understand the xenobiotic metabolism during the different life-stages of early development.The aim of the present study was to determine arylhydrocarbon receptor (AhR)-mediated activity during selected times of early development using qPCR, enzymatic activity through measurement of 7-ethoxyresorufin-Odeethylase(EROD) activity, and protein expression analysis. In the present study, gene expression of cyp1a, cyp1b1, cyp1c1, cyp1c2, and ahr2 as well as EROD activity were investigated up to 120 h postfertilization (hpf) after exposure to either β-naphthoflavone (BNF) or a polycyclic aromatichydrocarbons (PAH)-contaminated sediment extract from Vering Kanal in Hamburg (VK). Protein expression was measured at 72 hpf after exposure to 20 μg/L BNF. Altered proteins were identified by matrix assisted laser desorption ionization time-of-flight (MALDI-TOF) peptide mass fingerprinting. Distinct patterns of basal messenger RNA (mRNA) expressionwere found for each of the cyp1 genes, suggesting specific roles during embryonic development. All transcripts were induced by BNF and VK. ahr2 mRNA expression was significantly upregulated after exposure toVK. All cyp1 genes investigated showed a temporal decline in expression at 72 hpf. The significant decline of Hsp 90β protein at 72 hpf after exposure to BNF may suggest an explanation for the decline of cyp1 genes at this time point as Hsp 90β is of major importance for the functioning of the Ah-receptor. EROD activity measured in embryos was significantly induced after 96 hpf of exposure to BNF or VK. Together, these results demonstrate distinct temporal patterns of cyp1 genes and protein activities in zebrafish embryos as well as show a need to investigate further the xenobiotic biotransformation system during early development of zebrafish.
  •  
18.
  • Böttcher, Melanie, et al. (författare)
  • Comparison of in vitro and in situ genotoxicity in the Danube River by means of the comet assay and the micronucleus test
  • 2010
  • Ingår i: Mutation research. Genetic toxicology and environmental mutagenesis. - Amsterdam, Neteherlands : Elsevier. - 1383-5718 .- 1879-3592. ; 700:1-2, s. 11-17
  • Tidskriftsartikel (refereegranskat)abstract
    • Genotoxicity can be correlated with adverse reproductive effects or may even result in elevated extinction risk for particular species of an ecosystem. It may thus be a valuable tool for screening of pollution and potential environmental harm. Since many genotoxicants tend to adsorb on to particulate matter, sediments and suspended materials are of particular interest for genotoxicity screening under field conditions. In order to correlate the genotoxic potential of sediments with genetic damage in fish, rainbow-trout liver (RTL-W1) cells were exposed in vitro to acetone extracts of sediments collected at 10 selected sites along the upper Danube River and analyzed in the comet and micronucleus assays. These in vitro results were compared with micronucleus formation in erythrocytes of the European barbel (Barbus barbus) caught int he field. The two in vitro bioassays showed excellent correlation, indicating comparability of genotoxic potentials in vitro. Sampling sites could be clearly differentiated with respect to severity of effects, with Rottenacker as the most heavily contaminated site, Ehingen and Schwarzach as moderately genotoxic,and with the weakest effects in the tributary Lauchert. All other sediment extracts showed intermediate genotoxic or clastogenic effects. In situ, micronucleus formation in barbel erythrocytes indicated severe genotoxicity at Rottenacker, moderate effects at Ehingen, but minor contamination at Riedlingen and Sigmaringen. In situ observations thus showed excellent correlation with corresponding in vitro tests and document the ecological relevance of in vitro studies with sediment extracts. With respect to the ecological status of the Danube River, the results overall indicate a moderate to severe genotoxic potential with a highly differential localization.
  •  
19.
  • Cormier, Bettie, 1993-, et al. (författare)
  • Chronic feeding exposure to virgin and spiked microplastics disrupts essential biological functions in teleost fish
  • 2021
  • Ingår i: Journal of Hazardous Materials. - : Elsevier. - 0304-3894 .- 1873-3336. ; 415
  • Tidskriftsartikel (refereegranskat)abstract
    • Toxicity of polyethylene (PE) and polyvinyl chloride (PVC) microplastics (MPs), either virgin or spiked with chemicals, was evaluated in two short-lived fish using a freshwater species, zebrafish, and a marine species, marine medaka. Exposures were performed through diet using environmentally relevant concentrations of MPs over 4 months. No modification of classical biomarkers, lipid peroxidation, genotoxicity or F0 behaviour was observed. A significant decrease in growth was reported after at least two months of exposure. This decrease was similar between species, independent from the type of MPs polymer and the presence or not of spiked chemicals, but was much stronger in females. The reproduction was evaluated and it revealed a significant decrease in the reproductive output for both species and in far more serious numbers in medaka. PVC appeared more reprotoxic than PE as were MPs spiked with PFOS and benzophenone-3 compared to MPs spiked with benzo[a]pyrene. Further, PVC-benzophenone-3 produced behavioural disruption in offspring larvae. These results obtained with two species representing different aquatic environments suggest that microplastics exert toxic effects, slightly different according to polymers and the presence or not of sorbed chemicals, which may lead in all cases to serious ecological disruptions.
  •  
20.
  • Cormier, Bettie, 1993-, et al. (författare)
  • Multi-Laboratory Hazard Assessment of Contaminated Microplastic Particles by Means of Enhanced Fish Embryo Test With the Zebrafish (Danio rerio)
  • 2019
  • Ingår i: Frontiers in Environmental Science. - : Frontiers Media S.A.. - 2296-665X. ; 7
  • Tidskriftsartikel (refereegranskat)abstract
    • As wide-spread pollutants in the marine environment, microplastics (MPs) have raised public concern about potential toxic effects in aquatic organisms, and, among others, MPs were suspected to act as a vector for organic pollutants to biota. The purpose of the present study was to investigate effects by three model pollutants, oxybenzone (BP3), benzo[a] pyrene (BaP), and perfluorooctane sulfonate (PFOS) adsorbed to polyethylene MPs on the basis of a standard assay, the acute fish embryo toxicity test (FET; OECD TG 236) with zebrafish (Danio rerio) supplemented by additional endpoints such as induction of ethoxyresorufin-O-deethylase (EROD) activity, modification of cyp1a gene transcription and changes in larval swimming behavior. FET assays were performed in three laboratories using slightly different husbandry and exposure conditions, which, however, were all fully compatible with the limits defined by OECD TG 236. This allowed for testing of potential changes in the FET assay due to protocol variations. The standard endpoints of the FET (acute embryotoxicity) did not reveal any acute toxicity for both virgin MPs and MPs spiked with BP3, BaP, and PFOS. With respect to sublethal endpoints, EROD activity was increased after exposure to MPs spiked with BP3 (3 h pulse) and MPs spiked with BaP (96 h continuous exposure). Cyp1a transcription was increased upon exposure to MPs spiked with BP3 or BaP. For the selected combination of MPs particles and contaminants, the basic FET proved not sensitive enough to reveal effects of (virgin and spiked) MPs. However, given that the FET can easily be supplemented by a broad variety of more subtle and sensitive endpoints, an enhanced FET protocol may provide a relevant approach with developmental stages of a vertebrate animal model, which is not protected by current EU animal welfare legislation (Directive EU 2010/63).
  •  
21.
  • Cormier, Bettie, 1993-, et al. (författare)
  • Sorption and desorption kinetics of PFOS to pristine microplastic
  • 2022
  • Ingår i: Environmental Science and Pollution Research. - : Springer. - 0944-1344 .- 1614-7499. ; 29:3, s. 4497-4507
  • Tidskriftsartikel (refereegranskat)abstract
    • The sorption processes of persistent organic pollutants on microplastics particles are poorly understood. Therefore, the present study investigated the sorption processes of perfluorooctanesulfonate (PFOS) on polyethylene (PE) microplastic particles (MPs) which are representing a prominent environmental pollutant and one of the most abundant microplastic polymers in the aquatic environment, respectively. The focus was set on the investigation of the impact of the particle size on PFOS sorption using four different PE MPs size ranges. The sorption kinetics for 6 months was studied with one selected size range of PE MPs. Besides, the desorption of PFOS from PE MPs under simulated digestive conditions was carried out by using artificial gut fluid mimicking the intestinal juice of fish. The investigation of the size effects of particles over 6 months demonstrated a linear increase of PFOS concentration sorbed onto PE with a decrease of the particle size. Thus, our findings implicate efficient sorption of PFOS onto PE MPs of different sizes. The results showed that PFOS desorbed from the PE MPs into the artificial gut fluid with a rate of 70 to 80%. Besides, a longer exposure of PE MPs to PFOS leads to a higher concentration adsorbed by PE MPs, which may favor the ingestion of higher concentration of PFOS, and thus represents a higher risk to transfer relevant concentrations of PFOS during digestion.
  •  
22.
  • Di Paolo, Carolina, et al. (författare)
  • Bioassay battery interlaboratory investigation of emerging contaminants in spikedwater extracts : Towards the implementation of bioanalytical monitoring tools inwater quality assessment and monitoring
  • 2016
  • Ingår i: Water Research. - : Elsevier. - 0043-1354 .- 1879-2448. ; 104, s. 473-484
  • Tidskriftsartikel (refereegranskat)abstract
    • Bioassays are particularly useful tools to link the chemical and ecological assessments in water quality monitoring. Different methods cover a broad range of toxicity mechanisms in diverse organisms, and account for risks posed by non-target compounds and mixtures. Many tests are already applied in chemical and waste assessments, and stakeholders from the science-police interface have recommended their integration in regulatory water quality monitoring. Still, there is a need to address bioassay suitability to evaluate water samples containing emerging pollutants, which are a current priority in water quality monitoring. The presented interlaboratory study (ILS) verified whether a battery of miniaturized bioassays, conducted in 11 different laboratories following their own protocols, would produce comparable results when applied to evaluate blinded samples consisting of a pristine water extract spiked with four emerging pollutants as single chemicals or mixtures, i.e. triclosan, acridine, 17α-ethinylestradiol (EE2) and 3-nitrobenzanthrone (3-NBA). Assays evaluated effects on aquatic organisms from three different trophic levels (algae, daphnids, zebrafish embryos) and mechanism-specific effects using in vitro estrogenicity (ER-Luc, YES) and mutagenicity (Ames fluctuation) assays. The test battery presented complementary sensitivity and specificity to evaluate the different blinded water extract spikes. Aquatic organisms differed in terms of sensitivity to triclosan (algae > daphnids > fish) and acridine (fish > daphnids > algae) spikes, confirming the complementary role of the three taxa for water quality assessment. Estrogenicity and mutagenicity assays identified with high precision the respective mechanism-specific effects of spikes even when non-specific toxicity occurred in mixture. For estrogenicity, although differences were observed between assays and models, EE2 spike relative induction EC50 values were comparable to the literature, and E2/EE2 equivalency factors reliably reflected the sample content. In the Ames, strong revertant induction occurred following 3-NBA spike incubation with the TA98 strain, which was of lower magnitude after metabolic transformation and when compared to TA100. Differences in experimental protocols, model organisms, and data analysis can be sources of variation, indicating that respective harmonized standard procedures should be followed when implementing bioassays in water monitoring. Together with other ongoing activities for the validation of a basic bioassay battery, the present study is an important step towards the implementation of bioanalytical monitoring tools in water quality assessment and monitoring.
  •  
23.
  • Di Paolo, Carolina, et al. (författare)
  • The value of zebrafish as an integrative model in effect-directed analysis : a review
  • 2015
  • Ingår i: Environmental Sciences Europe. - : Springer. - 2190-4707 .- 2190-4715. ; 27:8, s. 1-11
  • Forskningsöversikt (refereegranskat)abstract
    • Bioassays play a central role in effect-directed analysis (EDA), and their selection and application have to consider rather specific aspects of this approach. Meanwhile, bioassays with zebrafish, an established model organism in different research areas, are increasingly being utilized in EDA. Aiming to contribute for the optimal application of zebrafish bioassays in EDA, this review provides a critical overview of previous EDA investigations that applied zebrafish bioassays, discusses the potential contribution of such methods for EDA and proposes strategies to improve future studies. Over the last 10 years, zebrafish bioassays have guided EDA of natural products and environmental samples. The great majority of studies performed bioassays with embryos and early larvae, which allowed small-scale and low-volume experimental setups, minimized sample use and reduced workload. Biotesting strategies applied zebrafish bioassays as either the only method guiding EDA or instead integrated into multiple bioassay approaches. Furthermore, tiered biotesting applied zebrafish methods in both screening phase as well as for further investigations. For dosing, most of the studies performed solvent exchange of extracts and fractions to dimethyl sulfoxide (DMSO) as carrier. However, high DMSO concentrations were required for the testing of complex matrix extracts, indicating that future studies might benefit from the evaluation of alternative carrier solvents or passive dosing. Surprisingly, only a few studies reported the evaluation of process blanks, indicating a need to improve and standardize methods for blank preparation and biotesting. Regarding evaluated endpoints, while acute toxicity brought limited information, the assessment of specific endpoints was of strong value for bioactivity identification. Therefore, the bioassay specificity and sensitivity to identify the investigated bioactivity are important criteria in EDA. Additionally, it might be necessary to characterize the most adequate exposure windows and assessment setups for bioactivity identification. Finally, a great advantage of zebrafish bioassays in EDA of environmental samples is the availability of mechanism- and endpoint-specific methods for the identification of important classes of contaminants. The evaluation of mechanism-specific endpoints in EDA is considered to be a promising strategy to facilitate the integration of EDA into weight-of-evidence approaches, ultimately contributing for the identification of environmental contaminants causing bioassay and ecological effects.
  •  
24.
  • Dulio, Valeria, et al. (författare)
  • The NORMAN Association and the European Partnership for Chemicals Risk Assessment (PARC) : let’s cooperate!
  • 2020
  • Ingår i: Environmental Sciences Europe. - : Springer. - 2190-4707 .- 2190-4715. ; 32:1
  • Tidskriftsartikel (refereegranskat)abstract
    • The Partnership for Chemicals Risk Assessment (PARC) is currently under development as a joint research and innovation programme to strengthen the scientific basis for chemical risk assessment in the EU. The plan is to bring chemical risk assessors and managers together with scientists to accelerate method development and the production of necessary data and knowledge, and to facilitate the transition to next-generation evidence-based risk assessment, a non-toxic environment and the European Green Deal. The NORMAN Network is an independent, well-established and competent network of more than 80 organisations in the field of emerging substances and has enormous potential to contribute to the implementation of the PARC partnership. NORMAN stands ready to provide expert advice to PARC, drawing on its long experience in the development, harmonisation and testing of advanced tools in relation to chemicals of emerging concern and in support of a European Early Warning System to unravel the risks of contaminants of emerging concern (CECs) and close the gap between research and innovation and regulatory processes. In this commentary we highlight the tools developed by NORMAN that we consider most relevant to supporting the PARC initiative: (i) joint data space and cutting-edge research tools for risk assessment of contaminants of emerging concern; (ii) collaborative European framework to improve data quality and comparability; (iii) advanced data analysis tools for a European early warning system and (iv) support to national and European chemical risk assessment thanks to harnessing, combining and sharing evidence and expertise on CECs. By combining the extensive knowledge and experience of the NORMAN network with the financial and policy-related strengths of the PARC initiative, a large step towards the goal of a non-toxic environment can be taken.
  •  
25.
  • Espinosa-Ruiz, Cristóbal, et al. (författare)
  • Immunotoxicological effects of perfluorooctanesulfonic acid on European seabass are reduced by polyethylene microplastics
  • 2023
  • Ingår i: Fish and Shellfish Immunology. - : Elsevier. - 1050-4648 .- 1095-9947. ; 137
  • Tidskriftsartikel (refereegranskat)abstract
    • Marine environments receive plastic waste, where it suffers a transformation process into smaller particles. Among them, microplastics (MPs; <5 mm) are ingested by aquatic organisms leading to negative effects on animal welfare. The interactions between MPs, contaminants and organisms are poorly understood. To clarify this issue, European seabass (Dicentrarchus labrax L.) were fed with diets supplemented with 0 (control), polyethylene (PE) MPs (100 mg/kg diet), perfluorooctanesulfonic acid (PFOS, 4.83 μg/kg diet) or PFOS adsorbed to MPs (MPs-PFOS; final concentrations of 4.83 μg and 100 mg of PFOS and MP per kg of feed, respectively). Samples of skin mucus, serum, head-kidney (HK), liver, muscle, brain and intestine were obtained. PFOS levels were high in the liver of fish fed with the PFOS-diet, and markedly reduced when adsorbed to MPs. Compared to the control groups, liver EROD activity did not show any significant changes, whereas brain and muscle cholinesterase activities were decreased in all the groups. The histological and morphometrical study on liver and intestine showed significant alterations in fish fed with the experimental diets. At functional level, all the experimental diets affected the humoral (peroxidase, IgM, protease and bactericidal activities) as well as cellular (phagocytosis, respiratory burst and peroxidase) activities of HK leukocytes, being more marked those effects caused by the PFOS diet. Besides, treatments produced inflammation and oxidative stress as evidenced at gene level. Principal component analysis demonstrated that seabass fed with MPs-PFOS showed more similar effects to MPs alone than to PFOS. Overall, seabass fed with MPs-PFOS diet showed similar or lower toxicological alterations than those fed with MPs or PFOS alone demonstrating the lack of additive effects or even protection against PFOS toxicity.
  •  
26.
  • Fallet, Manon, 1992-, et al. (författare)
  • Present and future challenges for the investigation of transgenerational epigenetic inheritance
  • 2023
  • Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 172
  • Forskningsöversikt (refereegranskat)abstract
    • Epigenetic pathways are essential in different biological processes and in phenotype-environment interactions in response to different stressors and they can induce phenotypic plasticity. They encompass several processes that are mitotically and, in some cases, meiotically heritable, so they can be transferred to subsequent generations via the germline. Transgenerational Epigenetic Inheritance (TEI) describes the phenomenon that phenotypic traits, such as changes in fertility, metabolic function, or behavior, induced by environmental factors (e.g., parental care, pathogens, pollutants, climate change), can be transferred to offspring generations via epigenetic mecha-nisms. Investigations on TEI contribute to deciphering the role of epigenetic mechanisms in adaptation, adver-sity, and evolution. However, molecular mechanisms underlying the transmission of epigenetic changes between generations, and the downstream chain of events leading to persistent phenotypic changes, remain unclear. Therefore, inter-, (transmission of information between parental and offspring generation via direct exposure) and transgenerational (transmission of information through several generations with disappearance of the triggering factor) consequences of epigenetic modifications remain major issues in the field of modern biology.In this article, we review and describe the major gaps and issues still encountered in the TEI field: the general challenges faced in epigenetic research; deciphering the key epigenetic mechanisms in inheritance processes; identifying the relevant drivers for TEI and implement a collaborative and multi-disciplinary approach to study TEI. Finally, we provide suggestions on how to overcome these challenges and ultimately be able to identify the specific contribution of epigenetics in transgenerational inheritance and use the correct tools for environmental science investigation and biomarkers identification.
  •  
27.
  • Fassbender, Christopher, et al. (författare)
  • Gene-TEQ-a standardized comparative assessment of effects in the comet assay using genotoxicity equivalents
  • 2012
  • Ingår i: Journal of Environmental Monitoring. - Cambridge, United Kingdom : The Royal Society of Chemistry. - 1464-0325 .- 1464-0333. ; 14, s. 1325-1334
  • Tidskriftsartikel (refereegranskat)abstract
    • Existing methods for the comparison of genotoxic effects in the comet assay bear considerable disadvantages such as the problem to link information about concentration dependence and severity of effects. Moreover, given the lack of standardized protocols and the use of various standards, it may be extremely difficult to compare different studies. In order to provide a method for standardized comparative assessment of genotoxic effects, the concept of genotoxicity equivalents (Gene-TEQ) was developed. As potential reference compounds for genotoxic effects, three directly acting (N-methyl-N0-nitro-N-nitrosoguanidine (MNNG), methyl-methanesulfonate, and N-methyl-N-nitrosourea) and three indirectly acting (cyclophosphamide, dimethylnitrosamine, and 4-nitroquinoline-oxide) genotoxic substances were compared with respect to their cytotoxic (neutral red) and genotoxic (cometassay) concentration–response profiles in the permanent fish cell line RTL-W1. For further comparison, two sediment extracts from the upper Danube River were investigated as environmental samples. Based on the results of cytotoxicity and genotoxicity testing, MNNG was selected as the reference compound. At several exposure levels and durations, genotoxic effects of both the other pure substances and the environmental samples were calculated as percentages of the maximum MNNGeffect and related to the absolute MNNG effect (EC values). Thus, genotoxicity equivalent factors(Gene-TEQs) relative to MNNG could be calculated. Gene-TEQs can easily be applied to puresubstances, mixtures and field samples to provide information about their toxicity relative to the reference compound. Furthermore, the Gene-TEQ concept allows a direct comparison of environmental samples from different laboratories.
  •  
28.
  • Garcia-Käufer, Manuel, et al. (författare)
  • Genotoxic and teratogenic effect of freshwater sediment samples from the Rhine and Elbe River (Germany) in zebrafish embryo using a multi-endpoint testing strategy
  • 2015
  • Ingår i: Environmental Science and Pollution Research. - Heidelberg, Germany : Springer. - 0944-1344 .- 1614-7499. ; 22:21, s. 16341-16357
  • Tidskriftsartikel (refereegranskat)abstract
    • The embryotoxic potential of three model sediment samples with a distinct and well-characterized pollutant burden from the main German river basins Rhine and Elbe was investigated. The Fish Embryo Contact Test (FECT) in zebrafish (Danio rerio) was applied and submitted to further development to allow for a comprehensive risk assessment of such complex environmental samples. As particulate pollutants are constructive constituents of sediments, they underlay episodic source-sink dynamics, becoming available to benthic organisms. As bioavailability of xenobiotics is a crucial factor for ecotoxicological hazard, we focused on the direct particle-exposure pathway, evaluating through put-capable endpoints and considering toxicokinetics. Fish embryo and larvae were exposed toward reconstituted (freeze-dried) sediment samples on a microcosm-scale experimental approach. A range of different developmental embryonic stages were considered to gain knowledge of potential correlations with metabolic competence during the early embryogenesis. Morphological, physiological, and molecular endpoints were investigated to elucidate induced adverse effects, placing particular emphasis on genomic instability, assessed by the in vivo comet assay. Flow cytometry was used to investigate the extent of induced cell death, since cytotoxicity can lead to confounding effects. The implementation of relative toxicity indices further provides inter-comparability between samples and related studies. All of the investigated sediments represent a significant ecotoxicological hazard by disrupting embryogenesis in zebrafish. Beside the induction of acute toxicity, morphological and physiological embryotoxic effects could be identified in a concentration-response manner. Increased DNA strand break frequency was detected after sediment contact in characteristic non-monotonic dose–response behavior due to overlapping cytotoxic effects. The embryonic zebrafish toxicity model along with the in vivo comet assay and molecular biomarker analysis should prospectively be considered to assess the ecotoxicological potential of sediments allowing for a comprehensive hazard ranking. In order to elucidate mode of action, novel techniques such as flow cytometry have been adopted and proved to be valuable tools for advanced risk assessment and management.
  •  
29.
  • Grund, Stefanie, et al. (författare)
  • Assessment of fish health status in the Upper Danube River by investigation of ultrastructural alterations in the liver of barbel Barbus barbus
  • 2010
  • Ingår i: Diseases of Aquatic Organisms. - Luhe, Germany : Inter-Research. - 0177-5103 .- 1616-1580. ; 23, s. 235-248
  • Tidskriftsartikel (refereegranskat)abstract
    • Despite intensive efforts and tightened guidelines for improvement of water quality over the last 2 decades, declines of fish populations have been reported for several rivers around the world. The present study forms part of a comprehensive weight-of-evidence approach, which aims to identify potential causes for the decline in fish catches observed in the Upper Danube River. The major focus of the present study is the investigation of the health status of wild barbel Barbus barbus L. collected from 3 locations along the Danube River, which experienced different levels of contamination. Whereas the comparison of the condition factor (CF) of field fish with that of control fish revealed no differences, ultrastructural investigations indicated severe disturbance of hepatic cell metabolism in field fish from the more contaminated sites Rottenacker and Ehingen, compared to both control fish and field fish from the less contaminated site Riedlingen. The ultrastructural analysis provided information about reactions of e.g. the rough endoplasmic reticulum, peroxisomes, andmitochondria, indicating an impaired health status of barbel at the sampling sites Rottenacker and Ehingen. Even though a straightforward cause-effect relationship between sediment contamination and ultrastructural alterations could not be established, based on a meta-analysis and toxicity assays it may be suggested that sediment-bound xenobiotics at least partly account for the hepatocellular changes. A relationship between impaired fish health status and the decline of fish catches along the Upper Danube River cannot be excluded.
  •  
30.
  • Gustavsson, Lillemor, et al. (författare)
  • Industrial sludge containing pharmaceutical residues and explosives alters inherent toxic properties when co-digested with oat and post-treated in reed beds
  • 2014
  • Ingår i: Environmental Sciences Europe. - Heidelberg, Germany : Springer. - 2190-4707 .- 2190-4715. ; 26:8, s. 1-11
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Methane production as biofuels is a fast and strong growing technique for renewable energy. Substrateslike waste (e.g. food, sludge from waste water treatment plants (WWTP), industrial wastes) can be used as a suitable resource for methane gas production, but in some cases, with elevated toxicity in the digestion residue. Former investigations have shown that co-digesting of contaminated waste such as sludge together with other substrates canproduce a less toxic residue. In addition, wetlands and reed beds demonstrated good results in dewatering and detoxifying of sludge. The aim of the present study was to investigate if the toxicity may alter in industrial sludgeco-digested with oat and post-treatment in reed beds. In this study, digestion of sludge from Bjorkborn industrial area in Karlskoga (reactor D6) and co-digestion of the same sludge mixed with oat (reactor D5) and post-treatment in reed beds were investigated in parallel. Methane production as well as changes in cytotoxicity (Microtox(R); ISO 11348–3), genotoxicity (Umu-C assay; ISO/13829) and AhR-mediated toxicity (7-ethoxyresorufin-O-deethylase (EROD) assay using RTW cells) were measured.Results: The result showed good methane production of industrial sludge (D6) although the digested residue was more toxic than the ingoing material measured using microtox30min and Umu-C. Co-digestion of toxic industrial sludge and oat(D5) showed higher methane production and significantly less toxic sludge residue than reactor D6. Furthermore, dewatering and treatment in reed beds showed low and non-detectable toxicity in reed bed material and outgoingwater as well as reduced nutrients.Conclusions: Co-digestion of sludge and oat followed by dewatering and treatment of sludge residue in reed beds canbe a sustainable waste management and energy production. We recommend that future studies should involve co-digestion of decontaminated waste mixed with different non-toxic material to find a substrate mixture that producethe highest biogas yield and lowest toxicity within the sludge residue.
  •  
31.
  • Hafner, Christoph, et al. (författare)
  • Investigations on sediment toxicity of German rivers applying a standardized bioassay battery
  • 2015
  • Ingår i: Environmental Science and Pollution Research. - : Springer Berlin/Heidelberg. - 0944-1344 .- 1614-7499. ; 22:21, s. 16358-16370
  • Tidskriftsartikel (refereegranskat)abstract
    • River sediments may contain a huge variety of environmental contaminants and play a key role in the ecological status of aquatic ecosystems. Contaminants adsorbed to sediments and suspended solids may contribute directly or after remobilization to an adverse ecological and chemical status of surface water. In this subproject of the joint research project DanTox, acetonic Soxhlet extracts from three German river sediments from the River Rhine (Altrip and Ehrenbreitstein with moderate contamination) and River Elbe (Veringkanal Hamburg heavily contaminated) were prepared and redissolved in dimethyl sulfoxide (DMSO). These extracts were analyzed with a standard bioassay battery with organisms from different trophic levels (bacteria, algae, Daphnia, fish) as well as in the Ames test and the umuC test for bacterial mutagenicity and genotoxicity according to the respective OECD and ISO guidelines. In total, 0.01 % (standard) up to 0.25 % (only fish embryo test) of the DMSO sediment extract was dosed to the test systems resulting in maximum sediment equivalent concentrations (SEQ) of 2 up to 50 g l(-1). The sediment of Veringkanal near Hamburg harbor was significantly more toxic in most tests compared to the sediment extracts from Altrip and Ehrenbreitstein from the River Rhine. The most toxic effect found for Veringkanal was in the algae test with an ErC50 (72 h) of 0.00226 g l(-1) SEQ. Ehrenbreitstein and Altrip samples were about factor 1,000 less toxic. In the Daphnia, Lemna, and acute fish toxicity tests, no toxicity at all was found at 2 g l(-1) SEQ. corresponding to 0.01 % DMSO. Only when increasing the DMSO concentration the fish embryo test showed a 22-fold higher toxicity for Veringkanal than for Ehrenbreitstein and Altrip samples, while the toxicity difference was less evident for the Daphnia test due to the overlaying solvent toxicity above 0.05 % dimethyl sulfoxide (DMSO). The higher toxicities observed with the Veringkanal sample are supported by the PAH and PCB concentrations analyzed in the sediments. The sediment extracts of Altrip andVeringkanal were mutagenic in the Ames tester strain TA98 with metabolic activation (S9mix). The findings allow a better ecotoxicological characterization of the sediments extensively analyzed in all subprojects of the DanTox project (e. g., Garcia-Kaeufer et al. Environ Sci Pollut Res. doi: 10.1007/s11356-014-3894-4, 2014; Schiwy et al. Environ Sci Pollut Res. doi: 10.1007/s11356-014-31850, 2014; Hollert and Keiter 2015). In the absence of agreed limit values for sediment extracts in standard tests, further data with unpolluted reference sediments are required for a quantitative risk assessment of the investigated polluted sediments.
  •  
32.
  • Hausen, Jonas, et al. (författare)
  • Fishing for contaminants : identification of three mechanism specific transcriptome signatures using Danio rerio embryos
  • 2018
  • Ingår i: Environmental Science and Pollution Research. - : Springer. - 0944-1344 .- 1614-7499. ; 25:5, s. 4023-4036
  • Tidskriftsartikel (refereegranskat)abstract
    • In ecotoxicology, transcriptomics is an effective way to detect gene expression changes in response to environmental pollutants. Such changes can be used to identify contaminants or contaminant classes and can be applied as early warning signals for pollution. To do so, it is important to distinguish contaminant-specific transcriptomic changes from genetic alterations due to general stress. Here we present a first step in the identification of contaminant class-specific transcriptome signatures. Embryos of zebrafish (Danio rerio) were exposed to three substances (methylmercury, chlorpyrifos and Aroclor 1254, each from 24 to 48 hpf exposed) representing sediment typical contaminant classes. We analyzed the altered transcriptome to detect discriminative genes significantly regulated in reaction to the three applied contaminants. By comparison of the results of the three contaminants, we identified transcriptome signatures and biologically important pathways (using Cytoscape/ClueGO software) that react significantly to the contaminant classes. This approach increases the chance of finding genes that play an important role in contaminant class-specific pathways rather than more general processes.
  •  
33.
  • Hausen, Jonas, et al. (författare)
  • Fold-change threshold screening : a robust algorithm to unmask hidden gene expression patterns in noisy aggregated transcriptome data
  • 2015
  • Ingår i: Environmental Science and Pollution Research. - : Springer Berlin/Heidelberg. - 0944-1344 .- 1614-7499. ; 22:21, s. 16384-16392
  • Tidskriftsartikel (refereegranskat)abstract
    • Transcriptomics is often used to investigate changes in an organism's genetic response to environmental contamination. Data noise can mask the effects of contaminants making it difficult to detect responding genes. Because the number of genes which are found differentially expressed in transcriptome data is often very large, algorithms are needed to reduce the number down to a few robust discriminative genes. We present an algorithm for aggregated analysis of transcriptome data which uses multiple fold-change thresholds (threshold screening) and p values from Bayesian generalized linear model in order to assess the robustness of a gene as a potential indicator for the treatments tested. The algorithm provides a robustness indicator (ROBI) as well as a significance profile, which can be used to assess the statistical significance of a given gene for different fold-change thresholds. Using ROBI, eight discriminative genes were identified from an exemplary dataset (Danio rerio FET treated with chlorpyrifos, methylmercury, and PCB) which could be potential indicators for a given substance. Significance profiles uncovered genetic effects and revealed appropriate fold-change thresholds for single genes or gene clusters. Fold-change threshold screening is a powerful tool for dimensionality reduction and feature selection in transcriptome data, as it effectively reduces the number of detected genes suitable for environmental monitoring. In addition, it is able to unmask patterns in altered genetic expression hidden by data noise and reduces the chance of type II errors, e.g., in environmental screening.
  •  
34.
  • Hollert, Henner, et al. (författare)
  • A new sediment contact assay to assess particle-bound pollutants using zebrafish (Danio rerio) embryos
  • 2003
  • Ingår i: Journal of Soils and Sediments. - : Springer Science and Business Media LLC. - 1439-0108 .- 1614-7480. ; 3:3, s. 197-207
  • Tidskriftsartikel (refereegranskat)abstract
    • Goal, Scope and Background. Based on a bioassay battery coveringonly primary producers and consumers as well as degraders, the potential ecological hazard of sediments to vertebrates cannot be estimated comprehensively. Therefore, there is an urgent need to develop and standardize integrated vertebrate-based test systems for sediment investigation strategies. Whereas vertebrate-based in vitro systems have frequently been used for the investigation of aqueous samples, there is a significant lack of whole sediment assays. Thus, the purpose of the present study was: (1)to develop a rapid and reliable, but comprehensive method to investigate native sediments and particulate matters without preceding extraction procedures; (2) to compare the hazard potential of solid phase sediments to the effects of corresponding pore waters and organic extracts in order to characterize the bioavailability of the particle-bound pollutants; and (3) to relatively evaluate the embryotoxic effects of sediments from the catchment areas of the rivers Rhine, Neckar and Danube.Methods (or Main Features). To investigate the toxicity of sediment samples on vertebrates, the standard embryo toxicity test with the zebrafish (Danio rerio; Hamilton-Buchanan 1922) according to DIN 38415-6 was modified with respect to exposure scheme and toxicological endpoints. Sediments from the catchment area of the Neckar River were assessed using pore waters, acetonic extracts and native sediments in order to get inside into the potential bioavailability of particle-bound pollutants. A comprehensive test protocol for the investigation of native sediments in the embryo toxicity test with the zebrafish is presented.Results and Discussion. The fish embryo assay with Danio rerio can be carried out with both aqueous and organic sediment extracts as well as native (whole, solid phase) sediment samples. Elongation of exposure time from 48 to up to 196 h significantly increased the mortality. Using the fish egg assay with native sediments, a broad range of embryotoxic effects could be elucidated, including clear-cut dose-response curves for the embryotoxic effects of contaminated sediments; in contrast, absence ofembryotoxic effects could be demonstrated even for the highest test concentrations of unpolluted sediments. With native sediments, embryotoxicity was clearly higher than with corresponding pore waters, thus corroborating the view that – at least for fish eggs – the bioavailability of particle-bound lipophilic substances in native sediments is higher than generally assumed. The relative ranking of sediment toxicity was identical using both native sediments and sediment extracts, EC20 values of the latter, however, being eight time lower higher than with the native sediments. A comparison of the embryo toxic effects of samples from the Neckar area with locations along the Rhine and Danube rivers elucidated a broad range of results, thus indicating different levels of contamination.Conclusions. A modified protocol of the zebrafish embryo test allows the assessment of sediment toxicity in both aqueous extracts and native sediments. The isolated investigation of pore waters may result in a clear-cut underestimation of the bioavailability of lipophilic particle-bound substances (as determined by native sediments).Recommendations and Perspectives. The zebrafish embryo test with native (whole, solid phase) sediments appears very promising for the evaluation of the bioavailable fraction of lipophilicparticle-bound substances and can therefore be recommended for the evaluation of vertebrate toxicity in tiered sediment test strategies and dredging directives such as the HABAB-WSV. Whereas acetone extracts may be tested as a rough estimation of embryotoxicity, native sediment samples will provide a more comprehensive and realistic insight into the bioavailable hazard potential
  •  
35.
  •  
36.
  • Hollert, Henner, et al. (författare)
  • Eine Weight-of-Evidence-Studie zur Bewertung der Sedimentbelastung und des Fischrückgangs in der Oberen Donau [Assessing sediments and fish health using a weight-of-evidence approach : in search for the causes of fish decline in the Danube river]
  • 2009
  • Ingår i: Umweltwissenschaften und Schadstoff-Forschung. - Berlin : Springer. - 0934-3504 .- 1865-5084. ; 21:3, s. 260-263
  • Tidskriftsartikel (refereegranskat)abstract
    • Background and aim Despite intensive and continuous stocking and improvement of water quality since the 1970s, fish populations, especially those of the grayling (Thymallus thymallus), have declined over the last two decades in the upper Danube River (Germany). In order to assess 1) possible links between molecular/biochemical responses and ecologically relevant effects, and 2) if ecotoxicological effects might be related to the decline in fish catches in the upper Danube river, sediment samples and fish were collected at different locations and analyzed using a weight-of-evidence (WOE) approach with several lines of evidence. The objective of the presentation is to introduce the conceptual framework and to review results of the ongoing study. As previously addressed by Chapman and Hollert (2006) a variety of lines of evidence can be used in WOE studies. Briefly, 1) a comprehensive battery of acute and mechanism-specific bioassays was used to characterize the ecotoxicological hazard potential. 2) Histopathological investigations and the micronucleus assay with erythrocytes were applied, analyzing in situ parameters. 3) Diversity and abundance of benthic macroinvertebrates and fish as well as 4) persistent organic pollutants, endocrine disrupting substances, limnochemical parameters and the concentration of heavy metals were recorded. To identify organic contaminants a spotential causes of sediment toxicity assays, 5) effect directed analysis was applied. © 2009 Springer-Verlag.
  •  
37.
  • Hollert, Henner, et al. (författare)
  • Looking back - Looking forward : A novel multi-time slice weight-of-evidence approach for defining reference conditions to assess the impact of human activities on lake systems
  • 2018
  • Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 626, s. 1036-1046
  • Tidskriftsartikel (refereegranskat)abstract
    • Lake ecosystems are sensitive recorders of environmental changes that provide continuous archives at annual to decadal resolution over thousands of years. The systematic investigation of land use changes and emission of pollutants archived in Holocene lake sediments as well as the reconstruction of contamination, background conditions, and sensitivity of lake systems offer an ideal opportunity to study environmental dynamics and consequences of anthropogenic impact that increasingly pose risks to human well-being. This paper discusses the use of sediment and other lines of evidence in providing a record of historical and current contamination in lake ecosystems. We present a novel approach to investigate impacts from human activities using chemical-analytical, bioanalytical, ecological, paleolimnological, paleoecotoxicological, archeological as well as modeling techniques. This multi-time slice weight-of-evidence (WOE) approach will generate knowledge on conditions prior to anthropogenic influence and provide knowledge to (i) create a better understanding of the effects of anthropogenic disturbances on biodiversity, (ii) assess water quality by using quantitative data on historical pollution and persistence of pollutants archived over thousands of years in sediments, and (iii) define environmental threshold values using modeling methods. This technique may be applied in order to gain insights into reference conditions of surface and ground waters in catchments with a long history of land use and human impact, which is still a major need that is currently not yet addressed within the context of the European Water Framework Directive.
  •  
38.
  • Hollert, Henner, et al. (författare)
  • Wasserrahmenrichtlinie : Fortschritte und Defizite
  • 2007
  • Ingår i: Umweltwissenschaften und Schadstoff-Forschung. - : Springer. - 0934-3504 .- 1865-5084. ; 19:1 Suppl., s. 58-70
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: The water protection policy of the European Union sits on new footings since the end of 2000: The Water FrameworkDirective (WFD). By replacing, merging and renewing all parts of the European water protection policy from the 1970s, the WFD provides a consistent, transparent and comprehensive concept of what water management should be in the Europe of the coming decades. The new directive is aimed at a holistic approach towards integrated water protection. It sets ambitious high-quality goals to achieve a good status for European lakes and rivers primarily in ecological terms, gives details about the essential processes as well as instruments, and includes everything into a strict time schedule.Aim: This article adresses progress and shortcomings at the implementation of the WFD in general and with reference to two selected case studies (Rivers Elbe and Upper Danube).Results and Discussion: After introducing the WFD, its aims and exceptions, a policy summary and background document ‘Environmental objectives und the Water Framework Directive’ and the use of Environmental Quality Standards (EQS) for single ‘priority substances’ as well as ‘hazardous priority components’ is discussed. The initial characterization undertaken by the German states revealed that only about 14% of all surface waters are considered to meet the WFD objectives by the year of 2015. Approximately 60% of the water bodies assessed are at risk of failing the WFD objectives, if not systematic efforts are made to improve the quality. Screenings of sources and paths of exposure for ‘priority substances’ and ‘priority hazardous substances’ according WFD identified one distinct pollution source for surface waters: ‘Historical pollution from sediments’. Because of industrial emissions in the past several river catchment areas are expected to fail the standards demanded by the WFD, due to a risk of remobilization of contaminants from sediments. This holds true for the Rhine river with high loads of hexachlorobenzene (HCB) as well as for Elbe river, where contaminated sediments can be a severe problem. Therefore, integration of sediments into the holistic river basin management approach and their consideration within the ‘programmes of measures’ scheduled for 2009 is highly recommended. At present, a comprehensive weight-of-evidence study verifies whether the observed fish decline at the Upper Danube. River is caused by ecotoxicological hazard potentials of contaminated sediments.Outlook: Combined investigations of sediment contamination and mobility as well as acute and mechanism specific biotests in effect directed analyses/weight-of-evidence studies show grent potential for the assessment of chemically polluted rivers and should be included into the ‘programmes of measures’ within future management concepts.
  •  
39.
  • Islam, Naimul, et al. (författare)
  • Perfluorooctane sulfonic acid (PFOS) adsorbed to polyethylene microplastics : Accumulation and ecotoxicological effects in the clam Scrobicularia plana
  • 2021
  • Ingår i: Marine Environmental Research. - : Elsevier. - 0141-1136 .- 1879-0291. ; 164
  • Tidskriftsartikel (refereegranskat)abstract
    • Microplastics are widespread in the marine environment, whereby the uptake of these tiny particles by organisms, can cause adverse biological responses. Plastic debris also act as a vector of many contaminants, herein depending on type, size, shape and chemical properties, possibly intensifying their effects on marine organisms. This study aimed to assess the accumulation and potential toxicity of different sizes of microplastics with and without adsorbed perfluorooctane sulfonic acid (PFOS) in the clam Scrobicularia plana. Clams were exposed to low-density polyethylene microplastics (1 mg L-1) of two different sizes (4-6 and 20-25 μm) virgin and contaminated with PFOS (55.7 ± 5.3 and 46.1 ± 2.9 μg g-1 respectively) over 14 days. Microplastic ingestion, PFOS accumulation and filtration rate were determined along with a multi biomarker approach to assess the biological effects of microplastics ingestion. Biomarkers include oxidative stress (superoxide dismutase, catalase, glutathione peroxidases), biotransformation enzymes (glutathione-S-transferases activity), neurotoxicity (acetylcholinesterase activity), oxidative damage and apoptosis. Microplastics ingestion and PFOS accumulation was microplastic size dependent but not PFOS dependent and filtration rate was reduced at the end of the exposure. Reactive oxygen species in gills and digestive gland were generated as a result of exposure to both types of microplastics, confirming the disturbance of the antioxidant system. Larger virgin microparticles lead to stronger impacts, when compared to smaller ones which was also supported by the Integrated Biomarker Responses index calculated for both tissues. An anti-apoptotic response was detected in digestive glands under exposure to any of the MPs treatments. 
  •  
40.
  • Jernbro, Susanne, et al. (författare)
  • Perfluorooctane Sulfonate Increases the Genotoxicity of Cyclophosphamide in the Micronucleus Assay with V79 Cells : Further Proof of Alterations in Cell Membrane Properties Caused by PFOS
  • 2007
  • Ingår i: Environmental Science and Pollution Research. - : Ecomed. - 0944-1344 .- 1614-7499. ; 14:2, s. 85-87
  • Tidskriftsartikel (refereegranskat)abstract
    • Perfluorooctane sulfonate (PFOS; C8F17SO3–) is a fully fluorinated organic compound which has been manufactured for decades and was used widely in industrial and commercial products. The recent toxicological knowledge of PFOS mainly concerns mono-substance exposures of PFOS to biological systems, leaving the potential interactive effects of PFOS with other compounds as an area where understanding is significantly lacking. However, a recent study, reported the potential of PFOS to enhance the toxicity of two compounds by increasing cell membrane permeability. This is of particular concern since PFOS has been reported to be widely distributed in the environment where contaminants are known to occur in complex mixtures. In this study, PFOS was evaluated alone and in combination with cyclophosphamide (CPP) to investigate whether a presence of PFOS leads to an increased genotoxic potential of CPP towards hamster lung V79 cells. Genotoxicity was investigated using the micronucleus(MN) assay according to the recent draft ISO/DIS 21427-2 method. PFOS alone demonstrated no genotoxicity up to a concentration of 12.5 μg/ml. However, PFOS combined with two different concentrations of CPP, with metabolic activation, caused a significant increase in the number of micronucleated cells compared to treatments with CPP alone. These results provide a first indication that PFOS has the potential to enhance the genotoxic action of CPP towards V79 cells, suggesting, together with the alterations in cell membrane properties shown previously, that genotoxicity of complex mixtures may be increased significantly by changes in chemical uptake. Together with an earlier study performed by the own working group, it can be concluded that PFOS alone is not genotoxic in this bioassay using V79 cells up to 12.5 μg/ml, but that further investigations are needed to assess the potential interaction between PFOS and other substances, in particular regarding the impact of membrane alterations on the uptake of toxic substances.
  •  
41.
  • Kais, Britta, et al. (författare)
  • In vivo EROD assays with the zebrafish (Danio rerio) as rapid screening tools for the detection of dioxin-like activity
  • 2017
  • Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 590-591, s. 269-280
  • Tidskriftsartikel (refereegranskat)abstract
    • The present study compares two alternative in vivo approaches for the measurement of ethoxyresorufin-Odeethylase (EROD) activity in zebrafish (Danio rerio) following exposure to acetonic model sediment extracts: (1) the live-imaging EROD assay for the direct detection of EROD induction in individual livers via epifluorescence, and (2) the fish embryo EROD assay in subcellular fractions derived from entire zebrafish embryos after in vivo exposure.For toxicity assessment, each sediment extract was tested with the standard fish embryo test (FET). Upon completion of a functioning liver after 72 h, the embryos gave a distinct fluorescent signal in the liver, and a corresponding EROD activity could be detected in the fish embryo EROD assay. The exposure time in the live-imaging EROD assay was reduced to 3 h, which resulted in a stronger, less variable and more sensitive EROD response. Overall, the live-imaging and the fish embryo EROD assays showed the same tendencies and gave comparable results, e.g. a concentration-dependent increase in EROD activity at concentrations one order of magnitude below concentrations producing macroscopically visible abnormalities. At higher concentrations, however, a decrease of EROD activity was observed in either test. Both tests ranked the three model sediment extracts in the same order. Results indicate that both test systems complement each other and together provide a rapid and reliable in vivo tool to investigate the presence of dioxin-like substances in environmental samples.
  •  
42.
  • Karami, Ali, et al. (författare)
  • Fuzzy logic and adaptive neuro-fuzzy inference system for characterization of contaminant exposure through selected biomarkers in African catfish
  • 2013
  • Ingår i: Environmental Science and Pollution Research. - Heidelberg, Germany : Springer. - 0944-1344 .- 1614-7499. ; 20:3, s. 1586-1595
  • Tidskriftsartikel (refereegranskat)abstract
    • This study represents a first attempt at applying a fuzzy inference system (FIS) and an adaptive neuro-fuzzy inference system (ANFIS) to the field of aquatic biomonitoring for classification of the dosage and time of benzo[a]pyrene (BaP) injection through selected biomarkers in African catfish (Clarias gariepinus). Fish were injected either intramuscularly (i.m.) or intraperitoneally (i.p.) with BaP. Hepatic glutathione S-transferase (GST) activities, relative visceral fat weights (LSI), and four biliary fluorescent aromatic compounds (FACs) concentrations were used as the inputs in the modeling study. Contradictory rules in FIS and ANFIS models appeared after conversion of bioassay results into human language (rule-based system). A “data trimming”approach was proposed to eliminate the conflicts prior to fuzzification. However, the model produced was relevant only to relatively low exposures to BaP, especially through the i.m. route of exposure. Furthermore, sensitivity analysis was unable to raise the classification rate to an acceptable level. In conclusion, FIS and ANFIS models have limited applications in the field of fish biomarker studies.
  •  
43.
  • Keiter, Steffen, 1971-, et al. (författare)
  • A fuzzy logic-classification of sediments based on data from in vitro biotests
  • 2009
  • Ingår i: Journal of Soils and Sediments. - Heidelberg, Germany : Springer. - 1439-0108 .- 1614-7480. ; 9:3, s. 168-179
  • Tidskriftsartikel (refereegranskat)abstract
    • Background, aim, and scope: Ecotoxicological risk assessment of sediments is usually based on a multitude of data obtained from tests with different endpoints. In the present study, a fuzzy logic-based model was developed in order to reduce the complexity of these data sets and to classify sediments on the basis of results from a battery of in vitro biotests.Materials and methods: The membership functions were adapted to fit the specific sensitivity and variability of each biotest. For this end, data sets were categorized into three toxicity levels using the box plot and empirical methods. The variability of each biotest was determined to calculatethe range of the gradual membership. In addition, the biotests selected were ranked according to the biological organisation level in order to consider the ecological relevance of the endpoints measured by selected over- or underestimation of the toxicity levels. In the next step of the fuzzy logic model, a rule-base was implemented using if...and...then decisions to arrive at a system of five quality classes.Results: The results of the classification of sediments fromthe Rhine and Danube Rivers showed the highest correlation between the biotest results and the fuzzy logical ternative based on the empirical method (i.e. the classification of the data sets into toxicity levels).Discussion: Many different classification systems based on biological test systems are depending on respective datasets; therefore, they are difficult to compare with other locations. Furthermore, they don‘t consider the inherent variability of biotests and the ecological relevance of these test systems as well. In order to create a comprehensive risk assessment for sediments, mathematical models should be used which take uncertainties of biotest systems into account, since they are of particular importance for areliable assessment. In the present investigation, the variability and ecological relevance of biotests were incorporated into a classification system based on fuzzy logic. Furthermore, since data from different sites and investigations were used to create membership functions ofthe fuzzy logic, this classification system has the potential to be independent of locations.Conclusions: In conclusion, the present fuzzy logic classification model provides an opportunity to integrate expert knowledge as well as acute and mechanism-specific effects for the classification of sediments for an ecotoxicological risk assessment.Recommendations and perspectives: In order to achieve amore comprehensive classification, further investigation is needed to incorporate results of chemical analyses and in situ parameters. Furthermore, more discussions are necessary with respect to the relative weight attributed to different ecological and chemical parameters in order too btain a more precise assessment of sediments.
  •  
44.
  • Keiter, Steffen, et al. (författare)
  • Activities and identification of aryl hydrocarbon receptor agonists in sediments from the Danube river
  • 2008
  • Ingår i: Analytical and Bioanalytical Chemistry. - Berlin / Heidelberg : Springer. - 1618-2642 .- 1618-2650. ; 390:8, s. 2009-2019
  • Tidskriftsartikel (refereegranskat)abstract
    • This study is a consequence of a distinct fish decline in the Danube river since the beginning of the 1990s. In contrast to the decline of fish population, former studies have repeatedly documented that the water quality along the Danube river is improving. However, the conclusion of a pilot study in 2002 was that a high hazard potential is associated with local sediments. The present study documents that sediment samples from the Danube river showed comparatively high aryl hydrocarbon receptor mediated activity in biotests, using the cell lines GPC.2D.Luc, H4IIE (DR-CALUX®) and RTL-W1. The combination of chemical analysis, fractionation techniques and different in vitro tests revealed that priority pollutants could not explain the main induction, even though the concentrations of priority polycyclic aromatic hydrocarbons (PAHs) were very high (maximum in the tributary Schwarzach, sum of 16 EPA PAHs 26 μg/g). In conclusion, this investigation shows that nonpriority pollutants mainly mediate the high induction rates. Nevertheless, owing to the effects of PAHs towards fish and the connection between dioxin-like activity and carcinogenicity, the link between contamination and the fish population decline cannot be ruled out.
  •  
45.
  • Keiter, Steffen, 1971-, et al. (författare)
  • DanTox-a novel joint research project using zebrafish (Danio rerio) to identify specific toxicity and molecular modes of action of sediment-bound pollutants
  • 2010
  • Ingår i: Journal of Soils and Sediments. - Heidelberg, Germany : Springer. - 1439-0108 .- 1614-7480. ; 10:4, s. 714-717
  • Tidskriftsartikel (refereegranskat)abstract
    • Introduction: The European Water Framework Directive aimsto achieve a good ecological and chemical status in surface water of European rivers by the year 2015. Since sediments and particulate matter act as secondary sources for pollutants, applied sediment toxicology is perceived to play a major rolefor obtaining new knowledge that can contribute to successful attainment of the goal. However, the existing bioassays for sediment toxicity analyses do not provide sufficient data concerning bioavailability of environmental pollutants. In this regard, there is an urgent need to combine sediment contact assays with gene expression analysis to investigate mechanism-specific sediment toxicity.Purpose: The aim of the novel joint research project is todevelop a eukaryotic test system, which can be used to investigate the ecotoxicological effects of contaminated sediments on gene expression level (DNA-array and RT-PCR).Current ecotoxicological research customarily involves a battery of bioassays to cover different toxicological endpoints (e.g., teratogenicity, genotoxicity, mutagenicity, Ah-receptor mediated toxicity, neurotoxicity). In contrast, methods that detect alterations in gene expression offer deeper insight by elucidating how chemical exposure and/or environmental challenge affect multiple metabolic pathways leading to these particular kinds of toxic response. Gene expression profiles reflect the way cells and organisms adapt or respond to a changing environment.Conclusion: The present project aspires to increase the fundamental molecular and physiological knowledge concerning the mode of action of environmental toxicants in zebrafish (Danio rerio). By working with partners from the academic and research institutions as well as from industry and waterway regulations, the success of this basic research-driven joint project in terms of development and implementation of novel sediment toxicity methods will be realized.
  •  
46.
  • Keiter, Steffen, 1971-, et al. (författare)
  • Ecotoxicological assessment of sediment, suspended matter andwater samples in the upper danube river : a pilot study in search for the causes for the decline of fish catches
  • 2006
  • Ingår i: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 13:5, s. 308-319
  • Tidskriftsartikel (refereegranskat)abstract
    • Goals, Scope and Background. Fish populations, especially thoseof the grayling (Thymallus thymallus), have declined over thelast two decades in the upper Danube River between Sigmaringenand Ulm, despite intensive and continuous stocking and improvementof water quality since the 1970s. Similar problems havebeen reported for other rivers, e.g. in Switzerland, Great Britain,the United States and Canada. In order to assess if ecotoxicologicaleffects might be related to the decline in fish catchat the upper Danube River, sediment, suspended matter andwaste water samples from sewage treatment plants were collectedat selected locations and analyzed in a bioanalytical approachusing a battery of bioassays. The results of this pilotstudy will be used to decide if a comprehensive weight-of-evidencestudy is needed.Methods. Freeze-dried sediments and suspended particulate matterswere extracted with acetone in a Soxhlet apparatus. Organicpollutants from sewage water were concentrated usingXAD-resins. In order to investigate the ecotoxicological burden,the following bioassays were used: (1) neutral red assaywith RTL-W1 cells (cytotoxicity), (2) comet assay with RTLW1cells (genotoxicity), (3) Arthrobacter globiformis dehydrogenaseassay (toxicity to bacteria), (4) yeast estrogen screen assay(endocrine disruption), (5) fish egg assay with the zebrafish(Danio rerio; embryo toxicity) and (6) Ames test with TA98(mutagenicity).Results and Discussion. The results of the in vitro tests elucidateda considerable genotoxic, cytotoxic, mutagenic, bacteriotoxic,embryotoxic and estrogenic burden in the upper DanubeRiver, although with a very inhomogeneous distribution of effects.The samples taken from Riedlingen, for example, inducedlow embryo toxicity, but the second highest 17β-estradiol equivalentconcentration (1.8 ng/L). Using the fish egg assay with nativesediments, a broad range of embryotoxic effects could beelucidated, with clear-cut dose-response relationships for theembryotoxic effects of contaminated sediments. With nativesediments, embryotoxicity was clearly higher than with correspondingpore waters, thus corroborating the view that – atleast for fish eggs – the bioavailability of particle-bound lipophilicsubstances in native sediments is higher than generally assumed. The effect observed most frequently in the fish egg assay was a developmental delay. A comparison of our own results with locationsalong the rivers Rhine and Neckar demonstrated similaror even higher ranges of ecotoxicological burdens in theDanube River.Conclusions. The complex pattern of ecotoxicological effectscaused by environmental samples from the Danube River, whenassessed in an in vitro biotest battery using both acute and morespecific endpoints, showed that integration of different endpointsis essential for appropriate hazard assessment. Overall, theecotoxicological hazard potential shown has indeed to be consideredas one potential reason for the decline in fish catches atthe upper Danube River. However, based on the results of thispilot study, it is not possible to elucidate that chemically inducedalterations are responsible for the fish decline.Recommendations and Perspectives. In order to confirm the ecologicalrelevance of the in vitro results for the situation in thefield and especially for the decline of the grayling and otherfishes, further integrated investigations are required. For linkingthe weight of evidence obtained by in vitro assays and fishpopulation investigations, the application of additional, morespecific biomarkers (e.g. vitellogenin induction, EROD and micronucleusassay) has been initiated in fish taken from the fieldas well as in situ investigations.
  •  
47.
  • Kosmehl, Thomas, et al. (författare)
  • A combined DNA-microarray and mechanism-specific toxicity approach with zebrafish embryos to investigate the pollution of river sediments
  • 2012
  • Ingår i: Reproductive Toxicology. - Oxford, United Kingdom : Elsevier. - 0890-6238 .- 1873-1708. ; 33:2, s. 245-253
  • Tidskriftsartikel (refereegranskat)abstract
    • The zebrafish embryo has repeatedly proved to be a useful model for the analysis of effects by environmental toxicants. This proof-of-concept study was performed to investigate if an approach combining mechanism-specific bioassays with microarray techniques can obtain more in-depth insights into theecotoxicity of complex pollutant mixtures as present, e.g., in sediment extracts. For this end, altered gene expression was compared to data from established bioassays as well as to results from chemical analysis. Mechanism-specific biotests indicated a defined hazard potential of the sediment extracts, and microarray analysis revealed several classes of significantly regulated genes which could be related to the hazard potential. Results indicate that potential classes of contaminants can be assigned to sediment extracts by both classical biomarker genes and corresponding expression profile analyses of known substances. However, it is difficult to distinguish between specific responses and more universal detoxification of the organism.
  •  
48.
  • Le Bihanic, F., et al. (författare)
  • Organic contaminants sorbed to microplastics affect marine medaka fish early life stages development
  • 2020
  • Ingår i: Marine Pollution Bulletin. - : Elsevier. - 0025-326X .- 1879-3363. ; 154
  • Tidskriftsartikel (refereegranskat)abstract
    • The role of polyethylene microplastics 4–6 μm size (MPs) in the toxicity of environmental compounds to fish early life stages (ELS) was investigated. Marine medaka Oryzias melastigma embryos and larvae were exposed to suspended MPs spiked with three model contaminants: benzo(a)pyrene (MP-BaP), perfluorooctanesulfonic acid (MP-PFOS) and benzophenone-3 (MP-BP3) for 12 days. There was no evidence of MPs ingestion but MPs agglomerated on the surface of the chorion. Fish ELS exposed to virgin MPs did not show toxic effects. Exposure to MP-PFOS decreased embryonic survival and prevented hatching. Larvae exposed to MP-BaP or MP-BP3 exhibited reduced growth, increased developmental anomalies and abnormal behavior. Compared to equivalent waterborne concentrations, BaP and PFOS appeared to be more embryotoxic when spiked on MPs than when alone in seawater. These results suggest a relevant pollutant transfer by direct contact of MPs to fish ELS that should be included in the ecotoxicological risk assessment of MPs. 
  •  
49.
  • Le Du-Carrée, Jessy, et al. (författare)
  • Cocktail effects of tire wear particles leachates on diverse biological models : A multilevel analysis
  • 2024
  • Ingår i: Journal of Hazardous Materials. - : Elsevier. - 0304-3894 .- 1873-3336. ; 471
  • Tidskriftsartikel (refereegranskat)abstract
    • Tire wear particles (TWP) stand out as a major contributor to microplastic pollution, yet their environmental impact remains inadequately understood. This study delves into the cocktail effects of TWP leachates, employing molecular, cellular, and organismal assessments on diverse biological models. Extracted in artificial seawater and analyzed for metals and organic compounds, TWP leachates revealed the presence of polyaromatic hydrocarbons and 4-tert-octylphenol. Exposure to TWP leachates (1.5 to 1000 mg peq L-1) inhibited algae growth and induced zebrafish embryotoxicity, pigment alterations, and behavioral changes. Cell painting uncovered pro-apoptotic changes, while mechanism-specific gene-reporter assays highlighted endocrine-disrupting potential, particularly antiandrogenic effects. Although heavy metals like zinc have been suggested as major players in TWP leachate toxicity, this study emphasizes water-leachable organic compounds as the primary causative agents of observed acute toxicity. The findings underscore the need to reduce TWP pollution in aquatic systems and enhance regulations governing highly toxic tire additives.
  •  
50.
  • Legradi, J. B., et al. (författare)
  • An ecotoxicological view on neurotoxicity assessment
  • 2018
  • Ingår i: Environmental Sciences Europe. - : Springer. - 2190-4707 .- 2190-4715. ; 30
  • Forskningsöversikt (refereegranskat)abstract
    • The numbers of potential neurotoxicants in the environment are raising and pose a great risk for humans and the environment. Currently neurotoxicity assessment is mostly performed to predict and prevent harm to human populations. Despite all the efforts invested in the last years in developing novel in vitro or in silico test systems, in vivo tests with rodents are still the only accepted test for neurotoxicity risk assessment in Europe. Despite an increasing number of reports of species showing altered behaviour, neurotoxicity assessment for species in the environment is not required and therefore mostly not performed. Considering the increasing numbers of environmental contaminants with potential neurotoxic potential, eco-neurotoxicity should be also considered in risk assessment. In order to do so novel test systems are needed that can cope with species differences within ecosystems. In the field, online-biomonitoring systems using behavioural information could be used to detect neurotoxic effects and effect-directed analyses could be applied to identify the neurotoxicants causing the effect. Additionally, toxic pressure calculations in combination with mixture modelling could use environmental chemical monitoring data to predict adverse effects and prioritize pollutants for laboratory testing. Cheminformatics based on computational toxicological data from in vitro and in vivo studies could help to identify potential neurotoxicants. An array of in vitro assays covering different modes of action could be applied to screen compounds for neurotoxicity. The selection of in vitro assays could be guided by AOPs relevant for eco-neurotoxicity. In order to be able to perform risk assessment for eco-neurotoxicity, methods need to focus on the most sensitive species in an ecosystem. A test battery using species from different trophic levels might be the best approach. To implement eco-neurotoxicity assessment into European risk assessment, cheminformatics and in vitro screening tests could be used as first approach to identify eco-neurotoxic pollutants. In a second step, a small species test battery could be applied to assess the risks of ecosystems.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-50 av 68
Typ av publikation
tidskriftsartikel (56)
annan publikation (5)
forskningsöversikt (3)
konferensbidrag (2)
doktorsavhandling (2)
Typ av innehåll
refereegranskat (59)
övrigt vetenskapligt/konstnärligt (9)
Författare/redaktör
Keiter, Steffen, 197 ... (55)
Hollert, Henner (33)
Braunbeck, Thomas (18)
Cormier, Bettie, 199 ... (13)
Blanc, Mélanie, 1993 ... (11)
Cousin, Xavier (10)
visa fler...
Engwall, Magnus, 196 ... (9)
Scherbak, Nikolai, 1 ... (8)
Larsson, Maria, 1975 ... (7)
Hyötyläinen, Tuulia, ... (6)
Kosmehl, Thomas (6)
Schiwy, Sabrina (6)
Bégout, Marie-Laure (5)
Otte, Jens (5)
Bluhm, Kerstin (5)
Strähle, Uwe (5)
Brack, Werner (5)
Böttcher, Melanie (5)
Rüegg, Joelle (4)
Reifferscheid, Georg (4)
Cousin, X. (4)
van Bavel, Bert (3)
Brinkmann, Markus (3)
Alfonso, Sébastien (3)
Engwall, Magnus (3)
Beiras, R. (3)
Cachot, J. (3)
Legradi, Jessica (3)
Antczak, Philipp (3)
Grund, Stefanie (3)
Yeung, Leo W. Y., 19 ... (2)
Sjöberg, Viktor, 198 ... (2)
Kärrman, Anna, 1975- (2)
Kammann, Ulrike (2)
Batel, A. (2)
Braunbeck, T. (2)
O'Donovan, Sarit (2)
Bellas, J. (2)
Gambardella, C. (2)
Garaventa, F. (2)
Le Bihanic, F. (2)
Barrachina, Célia (2)
Keiter, Steffen, doc ... (2)
Scherbak, Nikolai, d ... (2)
Krauss, Martin (2)
Grunau, Christoph (2)
Zinsmeister, Christi ... (2)
Bour, Agathe (2)
Dulio, Valeria (2)
Hilscherova, Klara (2)
visa färre...
Lärosäte
Örebro universitet (68)
Uppsala universitet (3)
Stockholms universitet (2)
Göteborgs universitet (1)
Luleå tekniska universitet (1)
Mälardalens universitet (1)
visa fler...
Karolinska Institutet (1)
Sveriges Lantbruksuniversitet (1)
IVL Svenska Miljöinstitutet (1)
visa färre...
Språk
Engelska (66)
Tyska (2)
Forskningsämne (UKÄ/SCB)
Naturvetenskap (65)
Medicin och hälsovetenskap (5)
Teknik (2)

År

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy