Project description:17α-Ethinylestradiol (EE2) is a ubiquitous aquatic contaminant shown to decrease fish fertility at low concentrations, especially in fish exposed during development. The mechanisms of the decreased fertility are not fully understood. In this study, we perform transcriptome analysis by RNA sequencing of testes from zebrafish with previously reported lowered fertility due to exposure to low concentrations of EE2 during development. Fish were exposed to 1.2 and 1.6 ng/L (measured concentration) of EE2 from fertilization to 80 days of age, followed by 82 days of remediation in clean water.
Project description:17-ethinylestradiol (EE2) is a synthetic estrogen commonly used as an active substance in oral contraceptives. It is frequently found in waste water effluent and raise concern due to its persistent nature. EE2 binds to estrogen receptors with similar affinity to oestradiol and acts as one of the most potent hormone mimics found in the environment. Estrogen is involved in many aspects of the development of the neuroendocrine system influencing both brain structure and behavior. We and others have reported a significant effect on non-reproductive behaviors in adult fish and in recent studies we found that developmental exposure to EE2 resulted in an anxiogenic phenotype as adults even after a long remediation period. In this study we aim to study possible mechanisms behind the behavior alterations of zebrafish developmentally exposed to EE2 by sequencing the whole brain transcriptome. Zebrafish embryos were exposed to 0, 2.14 and 7.34 ng/L EE2 from 1 day to 80 days post fertilization. After the exposure period a remediation period of 120 days followed before the fish were sampled. 3 male brains from the control group (0 ng/L) and the 2.14 ng/L group were sampled and 3 female brains from the control group (0 ng/L) and 7.34 ng/L were sampled.
Project description:Zebrafish populations recently collected from the wild differ from domesticated populations in anxiety-related behaviors. We measured anxiety-related behaviors in wild and domesticated zebrafish populations and performed a multi-brain region transcriptional comparison using microarrays to try to understand the genetic changes that accompany behavioral adaptation to domestication. We performed a microarray analysis comparing the midbrain and telencephalon brain regions of male and female adult zebrafish from four populations varying in domestication history (Wild: Nadia (N) and Pargana (P), and Domesticated: Scientific Hatchery (S) and Transgenic Mosaic 1 (T)). We collected 16 samples per brain region (4 samples per zebrafish population, with 1 telencephalon sample missing for the S population). We attempted to maintain equal sex ratios within each zebrafish population, but this was not always possible due to sex biases within some populations.
Project description:Low temperatures may cause severe growth inhibition and mortality in fish. In order to understand the mechanism of cold tolerance, a transgenic zebrafish Tg (smyd1:m3ck) model was established to study the effect of energy homeostasis during cold stress. The muscle-specific promoter Smyd1 was used to express the carp muscle form III of creatine kinase (M3-CK), which maintained enzymatic activity at a relatively low temperature, in zebrafish skeletal muscle. In situ hybridization showed that M3-CK was expressed strongly in the skeletal muscle. When exposed to 13°C, Tg (smyd1:m3ck) fish maintained their swimming behavior, while the wild-type could not. Energy measurements showed that the concentration of ATP increased in Tg (smyd1:m3ck) versus wild-type fish at 28°C. After 2 h at 13°C, ATP concentrations were 2.16-fold higher in Tg (smyd1:m3ck) than in wild-type (P < 0.05). At 13°C, the ATP concentration in Tg (smyd1:m3ck) fish and wild-type fish was 63.3% and 20.0%, respectively, of that in wild-type fish at 28°C. Microarray analysis revealed differential expression of 1249 transcripts in Tg (smyd1:m3ck) versus wild-type fish under cold stress. Biological processes that were significantly overrepresented in this group included circadian rhythm, energy metabolism, lipid transport, and metabolism. These results are clues to understanding the mechanisms underlying temperature acclimation in fish.
Project description:Low temperatures may cause severe growth inhibition and mortality in fish. In order to understand the mechanism of cold tolerance, a transgenic zebrafish Tg (smyd1:m3ck) model was established to study the effect of energy homeostasis during cold stress. The muscle-specific promoter Smyd1 was used to express the carp muscle form III of creatine kinase (M3-CK), which maintained enzymatic activity at a relatively low temperature, in zebrafish skeletal muscle. In situ hybridization showed that M3-CK was expressed strongly in the skeletal muscle. When exposed to 13M-BM-0C, Tg (smyd1:m3ck) fish maintained their swimming behavior, while the wild-type could not. Energy measurements showed that the concentration of ATP increased in Tg (smyd1:m3ck) versus wild-type fish at 28M-BM-0C. After 2 h at 13M-BM-0C, ATP concentrations were 2.16-fold higher in Tg (smyd1:m3ck) than in wild-type (P < 0.05). At 13M-BM-0C, the ATP concentration in Tg (smyd1:m3ck) fish and wild-type fish was 63.3% and 20.0%, respectively, of that in wild-type fish at 28M-BM-0C. Microarray analysis revealed differential expression of 1249 transcripts in Tg (smyd1:m3ck) versus wild-type fish under cold stress. Biological processes that were significantly overrepresented in this group included circadian rhythm, energy metabolism, lipid transport, and metabolism. These results are clues to understanding the mechanisms underlying temperature acclimation in fish. Gene expression in triplicate samples of m3ck-13M-BM-0C, m3ck-28M-BM-0C, wt-13M-BM-0C, and wt-28M-BM-0C was assessed. Twelve microarray experiments were performed, each with three fish.