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| 2. |
- Book, Frida, 1989, et al.
(författare)
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Ecotoxicity screening of seven different types of commercial silica nanoparticles using cellular and organismic assays : Importance of surface and size
- 2019
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Ingår i: NanoImpact. - : Elsevier BV. - 2452-0748. ; 13, s. 100-111
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Tidskriftsartikel (refereegranskat)abstract
- We show that seven different types of commercial, biocide-free, colloidal silica products with mean particle sizes between 17 and 88 nm with 3 different surface chemistries (Na-stabilized, aluminized and silane-modified) are not toxic to the bacterium Pseudomonas putida, and the algae Raphidocelis subcapitata in the concentration range 5–500 mg/L. They are also not acutely toxic to Daphnia magna at concentrations up to 10,000 mg/L. Six silica particles are toxic to the gill cell line RTgill-W1 from Rainbow trout (Oncorhynchus mykiss), showing a clear concentration-response relationship with EC50 values between 13 and 92 mg/L. Toxicity in the fish cells decreases with increasing hydrodynamic size and is dependent on particle surface area. The average EC50 across the tested particles is 2.1 (±0.3) m2/L. Surface modifications clearly impact toxicity, with silane-modified particles showing no cytotoxicity. The reduced number of free silanol groups on the surface of the silane modified particle, in combination with an increased steric hindrance that prevents contact with the cells is a possible mechanism for the observed lack of toxicity. This is also in line with previous studies on silica nanoparticles in human toxicology. Overall, these findings show a generally low ecotoxicity of silica nanoparticles and indicate that silica particles of different sizes but identical surface chemistry could potentially be grouped into an assessment group under regulation such as REACH.
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| 3. |
- Carney Almroth, Bethanie, 1974, et al.
(författare)
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Assessing the effects of textile leachates in fish using multiple testing methods: From gene expression to behavior
- 2021
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Ingår i: Ecotoxicology and Environmental Safety. - : Elsevier BV. - 0147-6513 .- 1090-2414. ; 207
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Tidskriftsartikel (refereegranskat)abstract
- The textile industry, while of major importance in the world economy, is a toxic industry utilizing and emitting thousands of chemical substances into the aquatic environment. The aim of this project was to study the potentially harmful effects associated with the leaching of chemical residues from three different types of textiles: sportswear, children’s bath towels, and denim using different fish models (cell lines, fish larvae and juvenile fish). A combination of in vitro and in vivo test systems was used. Numerous biomarkers, ranging from gene expression, cytotoxicity and biochemical analysis to behavior, were measured to detect effects of leached chemicals. Principle findings indicate that leachates from all three types of textiles induced cytotoxicity on fish cell lines (RTgill-W1). Leachates from sportswear and towels induced mortality in zebrafish embryos, and chemical residues from sportswear reduced locomotion responses in developing larval fish. Sportswear leachate increased Cyp1a mRNA expression and EROD activity in liver of exposed brown trout. Leachates from towels induced EROD activity and VTG in rainbow trout, and these effects were mitigated by the temperature of the extraction process. All indicators of toxicity tested showed that exposure to textile leachate can cause adverse reactions in fish. These findings suggested that chemical leaching from textiles from domestic households could pose an ecotoxicological threat to the health of the aquatic environment.
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| 5. |
- Lammel, Tobias, et al.
(författare)
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Assessment of titanium dioxide nanoparticle toxicity in the rainbow trout (Onchorynchus mykiss) liver and gill cell lines RTL-W1 and RTgill-W1 under particular consideration of nanoparticle stability and interference with fluorometric assays
- 2018
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Ingår i: Nanoimpact. - : Elsevier BV. - 2452-0748. ; 11, s. 1-19
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Tidskriftsartikel (refereegranskat)abstract
- The increasing release of titanium dioxide (TiO2) nanoparticles (NPs) into the environment calls for a thorough assessment of their hazard to aquatic organisms. In vitro-assays based on continuous fish cell lines bear a high potential for determining the relative cytotoxic potency and mode of toxic action of environmental contaminants. Their application for testing of manufactured nanomaterials is however concomitant with technical challenges. The objective of this study was to determine the acute cytotoxicity of TiO2 NP in the rainbow trout (Onchorynchus mykiss) liver and gill cell lines RTL-W1 and RTgill-W1 under special consideration of so far widely ignored issues arising from poor NP stability and NP-dependent interference with fluorometric assays. We validated a protocol for the preparation of serum albumin-stabilized TiO2 NP dispersions in two growth media, which are frequently used in the culture of fish cells, Leibovitz-15 (L-15) and L-15/ex. The TiO2 NPs dispersions displayed high colloidal stability with their size distribution remaining unchanged over a concentration range that spans two orders of magnitude (1-100 mu g/ml) and an incubation period of 72 h. The TiO2 NPs dispersions caused little cytotoxicity upon 24 h and 72 h exposure, but NP agglomerates/aggregates were found inside intracellular vesicles in both gill and liver cells. Furthermore we demonstrated that TiO2 NPs, which remained adsorbed to the plasma membrane and/or were internalized by the cell interfere with fluorometric cell viability assays by attenuating part of the incident and emitted light resulting in effect overestimation. We propose modifications in the original assay protocol that may allow quantifying and mathematically correcting for the level of interference at different exposure concentrations.
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| 7. |
- Lammel, Tobias, et al.
(författare)
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Dietary uptake and effects of copper in Sticklebacks at environmentally relevant exposures utilizing stable isotope-labeled 65CuCl2 and 65CuO NPs
- 2021
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 757
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Tidskriftsartikel (refereegranskat)abstract
- © 2020 Elsevier B.V. Copper oxide nanoparticles (CuO NPs) accumulating in sediment can be taken up by invertebrates that serve as prey for fish. Thus, it is likely that the latter are exposed to CuO NPs via the gut. However, to this day it is unknown if CuO NPs can be taken up via the gastrointestinal tract and if and in which tissues/organs they accumulate. To address this knowledge gap, we synthesized CuO NPs enriched in the stable isotope 65Cu and incorporated them at low concentration (5 μg 65Cu g−1 ww food) into a practical diet prepared from worm homogenate, which was then fed to Three-spined Stickleback (Gasterosteus aculeatus) for 16 days. For comparison, fish were exposed to a diet spiked with a 65CuCl2 solution. Background Cu and newly taken up 65Cu in fish tissues/organs including gill, stomach, intestine, liver, spleen, gonad and carcass and feces were quantified by ICP-MS. In addition, expression levels of genes encoding for proteins related to Cu uptake, detoxification and toxicity (ctr-1, gcl, gr, gpx, sod-1, cat, mta and zo-1) were measured in selected tissues using RT-qPCR. The obtained results showed that feces of fish fed 65CuO NP-spiked diet contained important amounts of 65Cu. Furthermore, there was no significant accumulation of 65Cu in any of the analyzed internal organs, though 65Cu levels were slightly elevated in liver. No significant modulation in gene expression was measured in fish exposed to 65CuO NP-spiked diet, except for metallothionein, which was significantly upregulated in intestinal tissue compared to control fish. Altogether, our results suggests that dietary absorption efficiency of CuO NPs, their uptake across the gastrointestinal barrier into the organism, and effects on Cu-related genes is limited at low, environmentally relevant exposure doses (0.2 μg 65Cu −1 fish ww day−1).
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| 8. |
- Lammel, Tobias, et al.
(författare)
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Endocytosis, intracellular fate, accumulation, and agglomeration of titanium dioxide (TiO2) nanoparticles in the rainbow trout liver cell line RTL-W1
- 2019
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Ingår i: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 26:15, s. 15354-15372
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Tidskriftsartikel (refereegranskat)abstract
- There is increasing evidence that titanium dioxide (TiO2) nanoparticles (NPs) present in water or diet can be taken up by fish and accumulate in internal organs including the liver. However, their further fate in the organ is unknown. This study provides new insights into the interaction, uptake mechanism, intracellular trafficking, and fate of TiO2 NPs (Aeroxide (R) P25) in fish liver parenchymal cells (RTL-W1) in vitro using high-resolution transmission electron microscopy (TEM) and single particle inductively coupled plasma mass spectrometry (spICP-MS) as complementary analytical techniques. The results demonstrate that following their uptake via caveolae-mediated endocytosis, TiO2 NPs were trafficked through different intracellular compartments including early endosomes, multivesicular bodies, and late endosomes/endo-lysosomes, and eventually concentrated inside multilamellar vesicles. TEM and spICP-MS results provide evidence that uptake was nano-specific. Only NPs/NP agglomerates of a specific size range (30-100nm) were endocytosed; larger agglomerates were excluded from uptake and remained located in the extracellular space/exposure medium. NP number and mass inside cells increased linearly with time and was associated with an increase in particle diameter suggesting intracellular agglomeration/aggregation. No alterations in the expression of genes regulated by the redox balance-sensitive transcription factor Nrf-2 including superoxide dismutase, glutamyl cysteine ligase, glutathione synthetase, glutathione peroxidase, and glutathione S-transferase were observed. This shows that, despite the high intracellular NP burden (3.9x10(2)ngTi/mg protein after 24h) and NP-interaction with mitochondria, cellular redox homeostasis was not significantly affected. This study contributes to a better mechanistic understanding of in vitro particokinetics as well as the potential fate and effects of TiO2 NPs in fish liver cells.
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| 9. |
- Lammel, Tobias, et al.
(författare)
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Mixture toxicity effects and uptake of titanium dioxide (TiO2) nanoparticles and 3,3 ',4,4 '-tetrachlorobiphenyl (PCB77) in juvenile brown trout following co-exposure via the diet
- 2019
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Ingår i: Aquatic Toxicology. - : Elsevier BV. - 0166-445X .- 1879-1514. ; 213
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Tidskriftsartikel (refereegranskat)abstract
- Titanium dioxide nanoparticles (n-TiO2) are among the man-made nanomaterials that are predicted to be found at high concentrations in the aquatic environment. There, they likely co-exist with other chemical pollutants. Thus, n-TiO2 and other chemical pollutants can be taken up together or accumulate independently from each other in prey organisms of fish. This can lead to dietary exposure of fish to n-TiO2-chemical pollutant mixtures. In this study, we examine if simultaneous dietary exposure to n-TiO2 and 3,3',4,4'-Tetrachlorobiphenyl (PCB77)-used as a model compound for persistent organic pollutants with dioxin-like properties-can influence the uptake and toxicological response elicited by the respective other substance. Juvenile brown trout (Salmo trutta) were fed custom-made food pellets containing n-TiO2, PCB77 or n-TiO2+PCB77 mixtures for 15 days. Ti and PCB77 concentrations in the liver were measured by ICP-MS and GC-MS, respectively. Besides, n-TiO2 uptake was assessed using TEM. Combination effects on endpoints specific for PCB77 (i.e., cytochrome P450 1A (CYP1A) induction) and endpoints shared by both PCB77 and n-TiO2 (i.e., oxidative stress-related parameters) were measured in intestine and liver using RT-qPCR and enzyme activity assays. The results show that genes encoding for proteins/enzymes essential for tight junction function (zo-1) and ROS elimination (sod-1) were significantly upregulated in the intestine of fish exposed to n-TiO2 and PCB77 mixtures, but not in the single-substance treatments. Besides, n-TiO2 had a potentiating effect on PCB77-induced CYP1A and glutathione reductase (GR) expression/enzyme activity in the liver. This study shows that simultaneous dietary exposure to nanomaterials and traditional environmental pollutants might result in effects that are larger than observed for the substances alone, but that understanding the mechanistic basis of such effects remains challenging.
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| 10. |
- Lammel, Tobias
(författare)
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Test feed development and methodological approaches allowing highly controlled dietary exposures to nano- and microparticulate contaminants in fish
- 2021
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Ingår i: MethodsX. - : Elsevier BV. - 2215-0161. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- © 2020 There is increasing concern that particulate contaminants including manufactured nanomaterials and nano- and microplastics taken up and or accumulating in lower-trophic level aquatic organisms results in dietary exposure of fish feeding on these organisms. Controlled feeding studies can help advance our understanding of dietary uptake, bioaccumulation, and associated effects of (nano)particulate contaminants in fish, and also provide information about their likelihood to be transferred along the trophic chain and or to act as vector for other, surface-adsorbed pollutants. However, traditional approaches to prepare test feed for dietary exposure studies where commercial fish feed such as flakes, granules or pellets are soaked or spray-spiked with dissolved chemicals are not well suitable for (nano-)particulate contaminants. Microplastics, which often have sizes in the µm to mm range, and manufactured nanomaterials, in particular those which are soluble, such as metal/metal oxide nanoparticles, have to be incorporated into the feed to avoid their dissociation and or dissolution before the feed is ingested by the animal to avoid undesired waterborne exposure, which may confound results. • Here we describe a methodological approach to produce worm-shaped food packages, that is a practical diet, of controlled diameter and length (in the millimeter range), which allows to prepare food rations with a weight in the order of a few milligrams and to adjust the food rations to the individual body wet weight of small experimental fish with high accuracy (±0.5 mg) without the need for weighing/proportioning the feed using a scale. • The method can be used to prepare test feed with internally incorporated particulate contaminants, such as manufactured nanomaterials and nano- and microplastics, to assess the latter's dietary uptake, bioaccumulation and associated toxicity in fish. We described two protocol variations: One using dry starting material, such as feed flakes, and one using liquid starting material, such as worm homogenate. • The method has been developed for academic research environments with no access to specialized equipment for test feed preparation, and uses utensils and inexpensive plastic ware belonging to the standard inventory of ecotoxicological research laboratories.
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