Project description:Purpose: This study aimed to identify differentially expressed genes and transcripts in zebrafish embryos and larvae following benzo[a]pyrene (BaP) exposure. Methods: Adult zebrafish (2 males × 4 females, N=6 replicate tanks for each treatment) were acclimated for 7 days in an 818 Low Temp Illuminated Incubator (Precision Scientific, Chennai, India) at 28.5°C. Next, adult fish were waterborne exposed to control or 50 μg/L (ppb) BaP for 7 days; ethanol was used as vehicle solvent, and final ethanol concentration was 0.1 mL/L (100 ppm) in all treatment groups. This dose of ethanol is not teratogenic to zebrafish. Water was changed and/or re-dosed daily. From day 7 to 11 of the parental exposure, eggs were collected, counted, and raised in normal conditions (control) or continuously exposed to 50 μg/L BaP until 3.3 and 96 hours post fertilization (hpf). At 3.3 or 96 hpf, embryos (200/pool) or larvae (10/pool) were collected and pooled. Total RNA was isolated for transcriptomic RNA sequencing with Illumina HiSeq2000 (2X100bp). RNA-seq reads were uploaded to the galaxy platform https://main.g2.bx.psu.edu/. RNA-seq reads were trimmed, filtered, and aligned to the zebrafish genome (Danio_rerio.Zv9.68) with the Tophat for Illumina tool. Counting and annotation of RNA-seq reads were performed with Partek Genomics Suite version 6.11. Refseq Transcripts (2013-04-10) and Ensembl Transcripts release 70 databases were used for gene and transcript annotation. Differential expression of gene and transcript reads between treatments was analyzed with R package EdgeR. Genes/transcripts with false discovery rate (FDR) less than 0.05 and absolute fold change greater than 1.5 were considered as significant. Differentially expressed genes were defined as genes with altered expression at either gene or transcript level. Results: Differential expression analysis with EdgeR revealed that gene expression was vastly different between 3.3 hpf zebrafish embryos and 96 hpf larvae. Using Refseq annotation, we found that 10644 out of 13950 transcribed zebrafish genes were differentially expressed between the two developmental time-points, with 5961 up-regulated genes and 4683 down-regulated genes in 96 hpf larvae compared with 3.3 hpf embryos. Similarly, using Ensembl annotation, 16529 out of 19886 transcribed zebrafish genes were differentially expressed, with 9318 up-regulated genes and 7211 down-regulated genes in 96 hpf larvae compared with 3.3 hpf embryos. In 3.3 hpf embryos, four genes and seven transcripts were differentially expressed after BaP exposure. In 96 hpf larvae, 447 and 484 zebrafish genes were significantly up- and down-regulated, respectively, by BaP exposure. Conclusions: Parental and developmental BaP exposure caused gene expression changes in zebrafish embryos and larvae. Illumina HiSeq2000 deep sequencing was used to generate transcriptomic profiles for BaP-exposed 3.3 hpf zebrafish embryos (n=3 for control, n=3 for BaP) and 96 hpf larvae (n=2 for control, n=2 for BaP).

Project description:Purpose: This study aimed to identify differentially expressed genes and transcripts in zebrafish embryos and larvae following benzo[a]pyrene (BaP) exposure. Methods: Adult zebrafish (2 males × 4 females, N=6 replicate tanks for each treatment) were acclimated for 7 days in an 818 Low Temp Illuminated Incubator (Precision Scientific, Chennai, India) at 28.5°C. Next, adult fish were waterborne exposed to control or 50 μg/L (ppb) BaP for 7 days; ethanol was used as vehicle solvent, and final ethanol concentration was 0.1 mL/L (100 ppm) in all treatment groups. This dose of ethanol is not teratogenic to zebrafish. Water was changed and/or re-dosed daily. From day 7 to 11 of the parental exposure, eggs were collected, counted, and raised in normal conditions (control) or continuously exposed to 50 μg/L BaP until 3.3 and 96 hours post fertilization (hpf). At 3.3 or 96 hpf, embryos (200/pool) or larvae (10/pool) were collected and pooled. Total RNA was isolated for transcriptomic RNA sequencing with Illumina HiSeq2000 (2X100bp). RNA-seq reads were uploaded to the galaxy platform https://main.g2.bx.psu.edu/. RNA-seq reads were trimmed, filtered, and aligned to the zebrafish genome (Danio_rerio.Zv9.68) with the Tophat for Illumina tool. Counting and annotation of RNA-seq reads were performed with Partek Genomics Suite version 6.11. Refseq Transcripts (2013-04-10) and Ensembl Transcripts release 70 databases were used for gene and transcript annotation. Differential expression of gene and transcript reads between treatments was analyzed with R package EdgeR. Genes/transcripts with false discovery rate (FDR) less than 0.05 and absolute fold change greater than 1.5 were considered as significant. Differentially expressed genes were defined as genes with altered expression at either gene or transcript level. Results: Differential expression analysis with EdgeR revealed that gene expression was vastly different between 3.3 hpf zebrafish embryos and 96 hpf larvae. Using Refseq annotation, we found that 10644 out of 13950 transcribed zebrafish genes were differentially expressed between the two developmental time-points, with 5961 up-regulated genes and 4683 down-regulated genes in 96 hpf larvae compared with 3.3 hpf embryos. Similarly, using Ensembl annotation, 16529 out of 19886 transcribed zebrafish genes were differentially expressed, with 9318 up-regulated genes and 7211 down-regulated genes in 96 hpf larvae compared with 3.3 hpf embryos. In 3.3 hpf embryos, four genes and seven transcripts were differentially expressed after BaP exposure. In 96 hpf larvae, 447 and 484 zebrafish genes were significantly up- and down-regulated, respectively, by BaP exposure. Conclusions: Parental and developmental BaP exposure caused gene expression changes in zebrafish embryos and larvae.

Project description:The impacts of maternal Cd on zebrafish from female to embryo which included fecundity, gametes development, growth, other reproductive functions, and gene expression of 5hpf embryo were up and down regulated after female pretreated with Cd. The mating rate decreased by 30 %. It can be observed in growth delay during 6-somite stage. The ceratohyal head angle of larvae is widest upon 35.6 M-NM-<M maternal Cd treatment and it was showed a dose response. Besides, pericardial edema occurred in some 96hpf larvae. There were showed 33 and 37 target genes appeared significantly down and up regulation after microarray assay, respectively. The major effect on gene up regulation was showed at the functional of transcription (occupied 18.9%) and down regulation at the functional of protein biosynthesis (occupied 33.3%). These results demonstrated that maternal Cd influenced the reproduction ability of female and causes development abnormal of embryo. Sexually mature zebrafish (D. rerio) of both sexes, obtained from the Institute of Cellular and Organismic Biology, Academia Sinica (Taipei, Taiwan), were kept in an aquarium supplied with dechlorinated, circulated, aerated local tap water at 28 M-BM-0C with a 14: 10-h light/dark cycle, and were fed Daphnia and shrimp. Fertilized eggs were incubated in M-bM-^@M-^\zebrafish solutionM-bM-^@M-^\ (E3 solution) which contained 5 mM NaCl, 0.17 mM KCl, 0.33 mM CaCl2, 0.33 mM MgSO4, and 1 ppm methylene blue (pH 7.2). Developing embryos of 5 h post-fertilization (hpf) were collected for total RNA extraction, and process of microarray assay. The number of hatched zebrafish larvae at 48 and 72 hpf were recorded. The larvae of 72 hpf larvae were collected for cartilage stain in order to observe the development of pharyngeal arch. Nguyen and Janssen (2001) reported that the LC50 at 96 h of Cd was 0.62~1.33 M-NM-<M for 12-dpf stage zebrafish, and our previous study showed that the zebrafish embryo could induced physiological response with 0.89 M-NM-<M Cd exposure (Wu et al., 2008). Hence, a 10M-CM-^W (8.9 M-NM-<M) , 20M-CM-^W (17.8 M-NM-<M) and 40M-CM-^W (35.6 M-NM-<M) dose of 0.89 M-NM-<M was used in female zebrafish. The Cd medium was prepared using completely dried CdCl2 (Sigma, St. Louis, MO) dissolved in 1 mL concentrated HCl; double-deionized water was used to prepare the 10 mg/L Cd stock solution, which was then diluted with zebrafish solution before being used in the exposure experiments. During all experiments, the test containers were cleaned with HNO3 and thoroughly rinsed with double-deionized water before use.

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Next Generation Sequencing (NGS) of zebrafish larvae transcriptome by 2,2',4,4'-tetrabromodiphenyl ether (BDE47) treatment

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