Fish models used for chemical exposure in toxicological studies are normally kept in barren tanks without any structural environmental enrichment. Here, we tested the combined effects of ...environmental enrichment and exposure to two mixtures of endocrine disrupting chemicals (EDCs) in zebrafish. Firstly, we assessed whether developmental exposure to an EDC mixture (MIX G1) combined with rearing the fish in an enriched environment influenced behaviour later in life. This was evaluated using locomotion tracking one month after exposure, showing a significant interaction effect between enrichment and the MIX G1 exposure on the measured locomotion parameters. After three months, we assessed behaviour using custom-made behaviour tanks, and found that enrichment influenced swimming activity. Control fish from the enriched environment were more active than control fish from the barren environment. Secondly, we exposed adult zebrafish to a separate EDC mixture (MIX G0) after rearing them in a barren or enriched environment. Behaviour and hepatic mRNA expression for thyroid-related genes were assessed. There was a significant interaction effect between exposure and enrichment on swimming activity and an effect of environment on latency to approach the group of conspecifics, where enriched fish took more time to approach the group, possibly indicating that they were less anxious. Hepatic gene expression of a thyroid-related gene (
) was significantly affected by EDC exposure, while enrichment had no discernible impact on the expression of the measured genes. In conclusion, environmental enrichment is important to consider when studying the effects of EDCs in fish.
The environment contains a multitude of man-made chemicals, some of which can act as endocrine disruptors (EDCs), while others can be immunotoxic. We evaluated thyroid disruption and immunotoxic ...effects in wild female perch (Perca fluviatilis) collected from two contaminated areas in Sweden; one site contaminated with per- and polyfluoroalkyl substances (PFASs) and two sites contaminated with polychlorinated biphenyls (PCBs), with one reference site included for each area. The hepatic mRNA expression of thyroid receptors α and β, and the thyroid hormone metabolising iodothyronine deiodinases (dio1, dio2 and dio3) were measured using real-time PCR, while the levels of thyroid hormone T3 in plasma was analysed using a radioimmunoassay. In addition, lymphocytes, granulocytes, and thrombocytes were counted microscopically. Our results showed lower levels of T3 as well as lower amounts of lymphocytes and granulocytes in perch collected from the PFAS-contaminated site compared to reference sites. In addition, expressions of mRNA coding for thyroid hormone metabolising enzymes (dio2 and dio3) and thyroid receptor α (thra) were significantly different in these fish compared to their reference site. For perch collected at the two PCB-contaminated sites, there were no significant differences in T3 levels or in expression levels of the thyroid-related genes, compared to the reference fish. Fish from one of the PCB-contaminated sites had higher levels of thrombocytes compared with both the second PCB lake and their reference lake; hence PCBs are unlikely to be the cause of this effect. The current study suggests that lifelong exposure to PFASs could affect both the thyroid hormone status and immune defence of perch in the wild.
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•Perch were collected from areas with long-term exposure to PFASs or PCBs.•Prolonged exposure to PFASs may affect the thyroid and immune systems in wild perch.•Thyroid hormone T3 levels were lower in perch from the PFAS contaminated site.•Expression of thra, dio2 and dio3 were affected at the PFAS contaminated site.•White blood cell counts were lower in perch from the PFAS contaminated site.
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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•Textiles leachates were screened for toxicity using in vitro and in vivo testing.•Leachates from sportswear, towels and jeans caused cytotoxicity in fish cell lines.•Some leachates induced mortality in zebrafish embryos and reduced larval locomotion responses.•Biomarkers (Cyp1a, EROD, VTG, MT-a, GSH) were induced in trout species in vivo.•Chemical leaching from textiles could pose an ecotoxicological threat in aquatic environments.
Locomotion-based behavioural endpoints have been suggested as suitable sublethal endpoints for human and environmental hazard assessment, as well as for biomonitoring applications. Larval stages of ...the sand goby (Pomatoschistus minutus) possess a number of attractive qualities for experimental testing that make it a promising species in behavioural ecotoxicology. Here, we present a study aimed at developing a toolkit for using the sand goby as novel species for ecotoxicological studies and using locomotion as an alternative endpoint in toxicity testing. Exposure to three contaminants (copper (Cu), di-butyl phthalate (DBP) and perfluorooctanoic acid (PFOA) was tested in the early life stages of the sand goby and the locomotion patterns of the larvae were quantified using an automatic tracking system. In a photo-motor test, sand goby larvae displayed substantially higher activity in light than in dark cycles. Furthermore, all tested compounds exerted behavioural alterations, such as hypo- and hyperactivity. Our experimental results show that sand goby larvae produce robust and quantifiable locomotive responses, which could be used within an ecotoxicological context for assessing the behavioural toxicity of environmental pollutants, with particular relevance in the Nordic region. This study thus suggests that sand goby larvae have potential as an environmentally relevant species for behavioural ecotoxicology, and as such offer an alternative to standard model species.
The Mekong Delta is host to a large number of freshwater species, including a unique group of facultative air‐breathing Anabantiforms. Of these, the striped snakehead (Channa striata), the climbing ...perch (Anabas testudineus), the giant gourami (Osphronemus goramy) and the snakeskin gourami (Trichogaster pectoralis) are major contributors to aquaculture production in Vietnam. The gastrointestinal responses to feeding in these four species are detailed here. Relative intestinal length was lowest in the snakehead, indicating carnivory, and 5.5‐fold greater in the snakeskin, indicating herbivory; climbing perch and giant gourami were intermediate, indicating omnivory. N‐waste excretion (ammonia‐N + urea‐N) was greatest in the carnivorous snakehead and least in the herbivorous snakeskin, whereas the opposite trend was observed for net K+ excretion. Similarly, the more carnivorous species had a greater stomach acidity than the more herbivorous species. Measurements of acid–base flux to water indicated that the greatest postprandial alkaline tide occurred in the snakehead and a potential acidic tide in the snakeskin. Additional findings of interest were high levels of both PCO2 (up to 40 mmHg) and HCO3− (up to 33 mM) in the intestinal chyme of all four of these air‐breathing species. Using in vitro gut sac preparations of the climbing perch, it was shown that the intestinal net absorption of fluid, Na+ and HCO3− was upregulated by feeding but not net Cl− uptake, glucose uptake or K+ secretion. Upregulated net absorption of HCO3− suggests that the high chyme (HCO3−) does not result from secretion by the intestinal epithelium. The possibility of ventilatory control of PCO2 to regulate postprandial acid–base balance in these air‐breathing fish is discussed.
This study is a text analysis of 30 master’s theses, written by students at the Swedish School of Library and Information Science in Borås 2005-2008, concerning the subject sociology of literature. ...The aim is to twofold; to show how the subject sociology of literature manifests itself within these LIS theses and to produce discourse arguments concerning sociology of literature as an LIS subject. The theorists I refer to in my study are Thomas. S Kuhn, Frickel & Gross and Richard Whitley, who devoted themselves to the theory of science. Their theories are used to explain how and why a subject, in this case sociology of literature, develops and why it is important to be able to justify and define limits vis-à-vis other academic subjects. Since LIS is an interdisciplinary based subject, it is interesting to try to find out what purpose and field of application the subject sociology of literature in specific has within the LIS field. This study has found that there are some common denominators in the analyzed theses concerning perspective, empirical material, theory and method. For example, a number of the authors used a gender perspective in their theses. If you choose to believe the authors of these theses, sociology of literature within Library and Information Science is necessary in order to remember the deeper meaning in literature.
Estrogen receptor beta (ERβ, Esr2) plays a pivotal role in folliculogenesis and ovulation, yet its exact mechanism of action is mainly uncharacterized.
We here performed ERβ ChIP-sequencing of mouse ...ovaries followed by complementary RNA-sequencing of wild-type and ERβ knockout ovaries. By integrating the ERβ cistrome and transcriptome, we identified its direct target genes and enriched biological functions in the ovary. This demonstrated its strong impact on genes regulating organism development, cell migration, lipid metabolism, response to hypoxia, and response to estrogen. Cell-type deconvolution analysis of the bulk RNA-seq data revealed a decrease in luteal cells and an increased proportion of theca cells and a specific type of cumulus cells upon ERβ loss. Moreover, we identified a significant overlap with the gene regulatory network of liver receptor homolog 1 (LRH-1, Nr5a2) and showed that ERβ and LRH-1 extensively bound to the same chromatin locations in granulosa cells. Using ChIP-reChIP, we corroborated simultaneous ERβ and LRH-1 co-binding at the ERβ-repressed gene Greb1 but not at the ERβ-upregulated genes Cyp11a1 and Fkbp5. Transactivation assay experimentation further showed that ERβ and LRH-1 can inhibit their respective transcriptional activity at classical response elements.
By characterizing the genome-wide endogenous ERβ chromatin binding, gene regulations, and extensive crosstalk between ERβ and LRH-1, along with experimental corroborations, our data offer genome-wide mechanistic underpinnings of ovarian physiology and fertility.
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