| Atrazine and the Sexual
Differentiation of the Brain and Gonads of Two South Florida Anurans |
| Lisa R. Ganser | |
| University of Miami |
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| Toads as Models |
| Goals |
| Develop toads as an alternative model for the effects of endocrine disruptors on sex differentiation. | |
| Augment results of Hayes et al. (2002) to include brain sexual differentiation. |
| Collection Sites |
| GONADS |
| Sexual Differentiation of the Gonads of the Toad |
| Genetic cues | |
| Hormonal cues |
| Organization and Activation |
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| When does sexual
differentiation of the gonads of Bufo quercicus and Bufo marinus take
place? Will atrazine affect the sexual differentiation of the gonads? |
| Slide 24 |
| Atrazine Dosage Experiment |
| Methods |
| Sample tissues @ Gosner stages 31-met. | ||
| Histology | ||
| General & Immunocytochemistry | ||
| Microscopy | ||
| Light & Confocal | ||
| Quantification | ||
| Gonads: complete sex diff., density of oocytes/testis | ||
| Neuro: immunofluorescence, cell density, soma size | ||
| Statistics--ANOVA | ||
| THE BRAIN |
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| Sexual Differentiation of the Brain |
| AVT |
| Reproductive behaviors | |
| AVT-sensitive areas of brain | |
| Orientation to breeding site | |
| Calling | |
| Call phonotaxis |
When does sexual differentiation of the brain occur in B. quercicus and B. marinus? Does atrazine affect the sexual differentiation of the brain and gonads of B. quercicus and B. marinus? |
| Predictions |
| Sex diff. gonads = Gosner st. 35 | |
| Sex diff. brain = post metamorphosis | |
| Sex diff. areas = amygdala | |
| Atrazine gonads = feminization @ low dose | |
| Atrazine brain = feminization |
| Importance |
| Amphibians and wildlife | |
| Florida | |
| Humans |
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| "My Fabulous Committee:" |
| My Fabulous Committee: | |
| Dr. Jim OÕReilly and | |
| Dr. John Lu, advisors | |
| Dr. Ed Green | |
| Dr. Bill Hopkins | |
| THE OÕLAB | |
| Ron, Mark, and Gabe | |
| Seth Tomchik | |
| Dennis Wasko | |
| Robyn OÕReilly | |
| Slide 39 |
| ANOVA |
| F-ratio error | |
| Dose=Tank(Dose) | |
| Stage=Tank x Stage | |
| Dose x Stage = | |
| Tank(Dose) x Stage | |
| F-distribution | |
| DoseÑfixed | |
| StageÑfixed | |
| Tank(Dose)Ñrandom | |
| Dose x Stage | |
| Tank(Dose) x Stage | |