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| 2. |
- Hallgren, Per, et al.
(författare)
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Synthetic estrogen directly affects fish biomass and may indirectly disrupt aquatic food webs
- 2014
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Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268. ; 33:4, s. 930-936
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Tidskriftsartikel (refereegranskat)abstract
- Endocrine-disrupting chemicals are known to alter the fitness of individual organisms via changes in growth, behavior, and reproduction. It is largely unknown, however, whether these effects cascade through the food web and indirectly affect other, less sensitive organisms. The authors present results from a mesocosm experiment whereby the effects of the synthetic estrogen 17α-ethinylestradiol (EE2) were quantified in pelagic communities. Treatment with EE2 at a concentration of 28 ng/L had no large effects on the pelagic communities composed only of phytoplankton and zooplankton. In communities where planktivorous roach (Rutilus rutilus) were also present, however, EE2 caused a significant reduction in fish biomass. Moreover, zooplankton biomass was higher in the EE2 treatments, suggesting that zooplankton may have been released from fish predation. Hence, the direct effect of EE2 on roach may have cascaded down the food web to produce positive indirect effects on zooplankton. This result was supported in complementary foraging experiments with roach, showing reduced foraging performance after exposure to EE2. Despite the observed negative effect of EE2 on roach and the positive indirect effect on zooplankton, these effects did not cascade to phytoplankton, possibly because only copepods, but not cladocerans—the major grazers in these systems—were released from fish predation. The authors conclude that the known reproductive impairment in fish by EE2 in combination with the disturbed foraging performance observed in the present study may be a disadvantage to fish that may result in increasing abundance or biomass of prey such as zooplankton. Hence, EE2 may have consequences for both the structure and function of freshwater communities.
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| 3. |
- Moberg, Christina, et al.
(författare)
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De unga gör helt rätt när de stämmer staten
- 2022
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Ingår i: Aftonbladet. - 1103-9000.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
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| 4. |
- Nikoleris, Lina, et al.
(författare)
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17α-Ethinylestradiol (EE2) treatment of wild roach (Rutilus rutilus) during early life development disrupts expression of genes directly involved in the feedback cycle of estrogen.
- 2015
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Ingår i: Comparative Biochemistry and Physiology Part - C: Toxicology and Pharmacology. - : Elsevier BV. - 1532-0456. ; 180, s. 56-64
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Tidskriftsartikel (refereegranskat)abstract
- Fish are more sensitive to introduced disturbances from synthetic endocrine disrupting compounds during early life phases compared with mature stages. 17α-Ethinylestradiol (EE2), which is the active compound in human oral contraceptives and hormone replacement therapies, is today ever present in the effluents from sewage treatment plants. EE2 targets and interacts with the endogenous biological systems of exposed vertebrates resulting in to large extents unknown short- and long-term effects. We investigated how EE2 exposure affects expression profiles of a large number of target genes during early life of roach (Rutilus rutilus). We exposed fertilized roach eggs collected from a lake in Southern Sweden to EE2 for 12weeks together with 1+-year-old roach in aquaria. We measured the gene expression of the estrogen receptor (esr)1/2a/2b, androgen receptor (ar), vitellogenin, cytochrome P450 (cyp)19a1a/1b in fertilized eggs; newly hatched larvae; 12-week-old fry; and juvenile wild roach (1+-year-old). Results shows that an EE2 concentration as low as 0.5ng/L significantly affects gene expression during early development. Gene expression responses vary both among life stages and molecular receptors. We also show that the gene profile of the estrogen feedback cycle to a large extent depends on the relationship between the three esr genes and the two cyp19a1 genes, which are all up-regulated with age. Results indicate that a disruption of the natural activity of the dominant esr gene could lead to detrimental biological effects if EE2 exposure occurs during development, even if this exposure occurred for only a short period.
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| 5. |
- Nikoleris, Lina
(författare)
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The estrogen receptor in fish and effects of synthetic estrogens in the environment - Ecological and evolutionary perspectives and societal awareness
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Synthetic hormones are a group of pharmaceuticals used for various human and animal treatments. However, consumption and disposal of these substances have also given rise to negative effects and environmental problems for organisms in the wild which is why these substances have been classified as estrogenic endocrine-disrupting chemicals (EDCs). Studies on the estrogen receptors (ers) and their genes are of particular interest when investigating emerging negative effects from estrogenic EDC contaminants. In vertebrates, the ers are well conserved between organisms and regulate activation and deactivation involved for example in growth, reproduction and development in both males and females. The initial aims of my research presented in this thesis were to show how the duplicated er genes in vertebrates, by studying fish and salmonid species in particular, are distributed, activated or disrupted by both ecological and pharmaceutical challenges. I have worked with three different fish species: Atlantic salmon (Salmo salar); brown trout (Salmo trutta); and roach (Rutilus rutilus) sampled from natural populations in the wild. I show that there is a complex interaction between estrogens and its receptors, depending on which tissues and life stages are investigated. I have also identified multiple ers in salmonids, which could affect their sensitivity to EDC exposure. In the framework of how 17α-ethinylestradiol (EE2) affects fish and the environment we linked exposure of EE2 to changes in behavior and gene expression and as such the consequences it might have for the structure and function of an ecosystem. Because of the recent focus on technical solutions for the removal of pharmaceutical EDCs in the environment a complementary aim was to investigate whether increased knowledge regarding the disposal and usage of EDCs, so called upstream work, could lower use of and prescriptions for the human female contraception EE2. For this I assessed the societal awareness among the main prescribers and decision makers in Sweden on the negative effects release of EE2 has on the environment. I show that providing nurse midwives with more knowledge and information about the negative consequences synthetic hormones have on ecosystems could lead to changes in their consultations practices and their prescriptions of EE2. This, in combination with updated recommendations regarding norms and practice for safe contraceptive care from authorities, could in the future help lower EE2 residues in the environment in the future. To conclude, this thesis identifies key factors for understanding how EDCs affect organisms. I show that ers vary in expression between both life stages and between tissues and that this should be considered when estimating risks for organisms after EDC exposure. This thesis also opens up a new and hitherto unappreciated field in the work surrounding the upstream knowledge and EDCs.
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| 6. |
- Nikoleris, Lina, et al.
(författare)
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Unraveling the estrogen receptor (er) genes in Atlantic salmon (Salmo salar) reveals expression differences between the two adult life stages but little impact from polychlorinated biphenyl (PCB) load.
- 2015
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Ingår i: Molecular and Cellular Endocrinology. - : Elsevier BV. - 1872-8057 .- 0303-7207. ; 400:C, s. 10-20
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Tidskriftsartikel (refereegranskat)abstract
- Estrogen receptors (ers) not only are activated by hormones but also interact with many human-derived environmental contaminants. Here, we present evidence for four expressed er genes in Atlantic salmon cDNA - two more ers (erα2 and erβ2) than previously published. To determine if er gene expression differs between two adult life-stages we sampled 20 adult salmon from the feeding phase in the Baltic Sea and during migration in the River Mörrum, Sweden. Results show that all four er genes are present in the investigated tissues, except for erα2 not appearing in the spleen. Overall, a profile analysis reveals the erα1 gene to be the most highly expressed er gene in both female and male Baltic Sea salmon tissues, and also in female River Mörrum salmon. In contrast, this gene has the lowest gene expression level of the four er genes in male salmon from the River Mörrum. The erα2 gene is expressed at the lowest levels in both female/male Baltic Sea salmon and in female River Mörrum salmon. Statistical analyses indicate a significant and complex interaction where both sex and adult life stage can impact er gene expression. Regression analyses did not demonstrate any significant relationship between polychlorinated biphenyl (PCB) body burden and er gene expression level, suggesting that accumulated pollutants from the Baltic Sea may be deactivated inside the salmon's lipid tissues and have limited impact on er activity. This study is the first comprehensive analysis of four er gene expression levels in two wild salmon populations from two different adult life stages where information about PCB load is also available.
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