SlideServe
Télécharger Obtenir Pro
Menu
Accueil Pro
Préférences
ApparenceLight Aide et commentaires
© SlideServe · v2026

Focusing on the Adverse Outcomes of ER-mediated Pathways

adora avatar
adora
23 diapositives · 370 Views · Sep 06, 2012

This study examines the adverse effects of endocrine-disrupting chemicals (EDCs) on medaka fish (Oryzias latipes), focusing on ER-mediated pathways. The research employs both Tier II and multigeneration fish tests to assess population-level responses and transgenerational sensitivity to EDCs. Key endpoints include reproductive metrics, gonadal morphology, and molecular responses relating to hormonal disruption. The findings aim to inform risk assessment protocols and establish dose-response relationships essential for environmental monitoring and regulatory frameworks.

#fate #pessimism #cytosol #meridian #local anesthetic #computer conferencing #steer wrestling #war film
Focusing on the Adverse Outcomes of ER-mediated Pathways - slide 1
01 / 23Focusing on the Adverse Outcomes of ER-mediated Pathways
1 / 17

Télécharger la présentation

Focusing on the Adverse Outcomes of ER-mediated Pathways
Une image / un lien ci-dessous est fourni (tel quel) pour télécharger la présentation

Politique de téléchargement : le contenu du site vous est fourni TEL QUEL pour votre information et votre usage personnel ; il ne peut être vendu, concédé sous licence ni partagé sur d’autres sites sans l’accord de son auteur.Le contenu vous est fourni TEL QUEL, pour votre information et votre usage personnel uniquement. Téléchargez la présentation en cliquant sur ce lien. Lors du téléchargement, si vous ne parvenez pas à télécharger une présentation, l’éditeur a peut-être supprimé le fichier de son serveur.Pendant le téléchargement, si vous ne parvenez pas à obtenir une présentation, le fichier a peut-être été supprimé par l’éditeur.

F I N

Plus de contenu associé

Transcription de la présentation

  1. Focusing on the Adverse Outcomes of ER-mediated Pathways Rodney Johnson ORD/MED McKim Conference September 16-18, 2008

  2. Female (XX) Male (XY) Medaka • Complete life cycle ~ 10 weeks • Small (adults ~0.3 to 0.5 grams) • Sexually dimorphic (fins and body shape) • Male sex-determination gene (DMY) identified and sequenced • Spawns daily (~25 to 35 eggs per spawn) • Genome sequenced • Gene arrays available • Large historical literature database

  3. Positive Attributes of Medaka for Short-term and Multigeneration Tests • Simple ID of genetic sex of individuals • Small aquaria and pair spawning • optimize replication • improve statistical power • Rapid life cycle reduces test duration

  4. Purpose of Tier II Fish Tests • Evaluate nature and extent of adverse effects for chemicals implicated in Tier I tests • Evaluate population-level responses to potential EDCs • Establish dose-response parameters for chemicals implicated as EDCs in Tier I tests

  5. Purpose of Multigeneration Fish Tests Test Development • Develop datasets for developing efficient Tier II test protocols. Risk Assessment • Evaluate transgenerational effects of EDCs • determine if present • if so, which MOAs (i.e. estrogens, androgens, etc) • if so, magnitude of effect

  6. Transgenerational Effects • Definition: a between-generation increase or decrease in sensitivity of the test organism to the test agent • Requirements for evaluation • Same test conditions for each generation - chemical concentration - life-stage - endpoint

  7. Medaka exposure system

  8. Test protocol and data analysis based on genotypic sex (DMY) • Set up breeding pairs: 1 male (DMY) and 1 female • Endpoints analyzed by sex genotype (XX) or (XY) • Gonad histology phenotype (ovary or testis) • Liver vitellogenin mRNA phenotype (high female or low male) • Secondary Sex: anal fin papillae phenotype

  9. 12 12 12 13 13 13 14 14 14 15 15 15 16 16 16 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10 11 11 Development Development Reproduction Reproduction F0 Multigeneration Bioassay DesignOctylphenol Generation Reproduction F1 F2 Exp. Weeks 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 General Notes 5 treatments & control 6 replicates / treatment Flow-thru exposure 1.8 L tank, flow = 20 ml/min • Developmental Endpoints Embryo F1 & F2 • Hatch • Mortality • Reproductive Endpoints Adult: F0,F1, F2 • Fecundity • Fertility • Growth • 2° Sex character • Vitellogenin • Histopathology • Sub-adult F1 & F2 • Growth • Genotypic sex (XX, XY) • Phenotypic sex • 2° Sex Character • Vitellogenin • Histological gonadal sex • Histopathology

  10. Control male • male phenotype • Estrogen-exposed male • female phenotype Endpoint: Anal fin papillae

  11. Phenotype: male (testis) Genotype: male (XY) Phenotype: female (ovary) Genotype: female (XX) Endpoint: Sex reversal Octylphenol 50 ppb Control Phenotype: female (ovary) Genotype: male (XY) Phenotype: female (ovary) Genotype: male (XY) Breeding Adult F1 Octylphenol 100 ppb Juvenile F2 Octylphenol 50 ppb

  12. Octylphenol Effects on Fecundity Eggs/day Concentration (ppb)

  13. Octylphenol effects on genotypic males

  14. In-vitro pathway Schmieder et.al. Cellular Organ Individual Population Molecular • Octylphenol binding to ER • Altered reproduction • Altered development • Liver sliceVtg (mRNA) • ER transcription factor Decreased numbers of animals ER-mediated Adverse-outcome Pathway Octylphenol In-vivo pathway Multigen assay Individual Molecular Cellular Organ Population ? -dose: reduced fecundity ♂ Liver Vtg (mRNA) Population reduction ? -dose: sex reversal (altered gamete ratios) Octylphenol-ER binding ER transcriptionfactors Altered sex-ratios ? ? Anal fin papillae -dose: mixed-sex gonad ? Gonadal morphology

  15. 11 12 13 14 15 Generation F0 Reproduction F1 1 2 3 4 5 6 7 Development Weeks 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 General Notes 5 treatments, control 6 replicates / treatment Flow-thru exposure 1.8 L tank, flow = 15 ml/min • Reproductive Endpoints F0 Adult • Fecundity • Fertility • Growth • 2° Sex character • Vitellogenin • Histopathology • Developmental Endpoints F1 • Embryo • Mortality • Hatch • Sub-adult • Growth • Genotypic sex (XX, XY) • Phenotypic sex • 2° Sex Character • Vitellogenin • Histological gonadal sex • Histopathology Bioassay Design 4-n-amylaniline (AAN)

  16. Effects of amylaniline on anal fin papillae Endpoints: Anal fin papillae Concentration (ppb)

  17. Endpoints: Liver Vitellogenin Concentration (ppb)

  18. AAN Effects on Growth Concentration (ppb)

  19. Endpoint: Fecundity

  20. Amylaniline effects across generations

  21. In-vitro pathway Schmieder et.al. Cellular Organ Individual Population Molecular • AAN bindingto ER • Altered reproduction • Altered development • Liver sliceVtg (mRNA) • Liver slice toxicity • ER transcription factor Decreased numbers of animals ER-mediated Adverse-outcome Pathway Amylaniline (AAN) In-vivo pathway Multigen assay Individual Molecular Cellular Organ Population ♂ Liver Vtg (mRNA) dose: Sex reversal (altered gamete ratios) AAN bindingto ER ER transcriptionfactors Altered sex-ratios ? Anal fin papillae ? dose: Mixed-sex gonad ? Gonadal morphology Population reduction ? ? dose: Reduced fecundity AAN bindingto Hbg ? ? Splenic/head-kidney pathology ? dose: Reduced growth

  22. Conclusions • The in-vivo bioassays suggest that the ER- mediated pathway is more sensitive than other adverse outcome pathways for both octylphenol and AAN • The AAN data suggests that the ER-pathway is only slightly more sensitive than aromatic amine toxicity. • The Effectopedia could be very helpful for constructing and evaluating pathways.

  23. Acknowledgements Student Services Contractors • Jessica Nagel • Maicie Sykes • Chad Blanksma • Hillery Waterhouse • Megyn Mereness Wilson Contract • Kevin Lott EPA • Douglas Lothenbach • Frank Whiteman • Kevin Flynn • Dean Hammermeister NRC • Mary Haasch