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CHAPTER 13 DIRECTED READING “Bad Boy”
A PLAGUE OF FROGS
(See key below)
Answer the following questions in the space provided. (4 points each)
- Why did the EPA want to run their own FETAX studies?
- Describe how a FETAX is performed.
- What was Mike Lannoo’s complaint about the previous FETAX work?
- What is the primary responsibility of the Minnesota Department of Health?
- How did Ted Koppel contribute to the investigation?
- What did Tietge think was the MPCA and NIEHS’s fundamental problem?
- What is SETAC?
- What effect would the seasonal rise and fall of the CWB have on the FETAX results?
- What is methoprene? Why did the methoprene experimenters use 5 different concentrations?
- Define static renewal.
- What does UV exposure do to methoprene?
- What were the results of the methoprene experiment?
- Describe the significance of the UV results.
- What was Gardiner’s special apparatus designed to test
- What was the purpose of the resin beads?
- What were they hoping to find in the water samples?
- What invalidated the results of the experiment?
- What saved the experiment?
- What was the marker that Gardiner and Bryant discovered?
- What basic concepts did Lannoo want everyone to remember?
- What might be the source of Retinoids in the Minnesota water?
- What is DAPTF and what is its mission?
- Where did Dave Gardiner, Sue Bryant, Muneoka and Bruce Blumberg believe the focus of the discussions should be?
- Describe Pieter Johnson’s work and the effect it had on the investigation.
- What was the “bad boy”?
KEY
CHAPTER 13 DIRECTED READING
A PLAGUE OF FROGS
Answer the following questions in the space provided. (4 points each)
1. Why did the EPA want to run their own FETAX studies?
To look for shortcomings in the assay. (Page 240)
2. Describe how a FETAX is performed.
Freshly laid African clawed frog eggs are harvested after fertilization and the protective jelly coating is removed. Eggs are then placed in a solution of the mixture being tested. The eggs hatch and become larvae.
After 96 hours of exposure, the larva is examined under the microscope. (Page 241)
3. What was Mike Lannoo’s complaint about the previous FETAX work?
Xenopus was “phylogenetically remote” from any native frog species. (Page 242)
4. What is the primary responsibility of the Minnesota Department of Health?
Well safety in the state. (Page 242)
5. How did Ted Koppel contribute to the investigation?
He noted that the well water was pumped for a deep aquifer in a different place than where the deformities were found. So why should there be any connection? (Page 243)
6. What did Tietge think was the MPCA and NIEHS’s fundamental problem?
Their assumption of a linkage between deformities in the filed and different developmental problems in the lab was to great a leap. They were assuming a correlation that they could not prove. (P. 243)
7. What is SETAC?
The Society of Environmental Toxicology and Chemistry; the main professional organization of toxicologists. (Page 246)
8. What effect would the seasonal rise and fall of the CWB have on the FETAX results?
The groundwater they tested was actually surface seepage that came from the lake. (Page 248)
9. What is methoprene? Why did the methoprene experimenters use 5 different concentrations?
To determine how much of the active ingredient was needed to cause the deformities (if they were in fact a cause.) (Page 248)
10. Define static renewal.
When the test solution is replenished every 2 days so the dose in restored as the compound breaks down or is metabolized by the organisms. (Page 249)
11. What does UV exposure do to methoprene?
It converts it into methoprene acid. (Page 250)
12. What were the results of the methoprene experiment?
The high concentration of methoprene had a 100% mortality rate. No other methoprene concentrations had any effect. The UV effect caused limb reductions in the hind limbs. (Page 250)
13. Describe the significance of the UV results.
It created another possible hypothesis for the cause of the deformities and eliminated methoprene as the sole cause. (Page 251)
14. What was Gardiner’s special apparatus designed to test?
A highly concentrated water sample from CWB. (Page 253)
15. What was the purpose of the resin beads?
To attract and collect organic compounds in the water. (Page 254)
16. What were they hoping to find in the water samples?
A chemical that mimicked retinoic acid. (Page 254)
17. What invalidated the results of the experiment?
The resin beads themselves activated a retinoic receptor. (Page 255)
18. What saved the experiment?
The jars of water Gardiner had collected had a retinoid in them. (Page 256)
19. What was the marker that Gardiner and Bryant discovered?
A unique bending of the leg bone, such that the 2 ends were pushed toward each other. “Bony triangles” (Page 256)
20. What basic concepts did Lannoo want everyone to remember?
Be wary of “model” species; use caution in overstating the importance of frogs as sentinel species; use peer-review. (Page 257)
21. What might be the source of Retinoids in the Minnesota water?
A pesticide or a derivative from a pesticide, a natural compound produced by plants, or microorganisms in the lake. (Page 257)
22. What is DAPTF and what is its mission?
Declining Amphibian Population Task Force. Organization that monitors the status of amphibians. (P. 258)
23. Where did Dave Gardiner, Sue Bryant, Muneoka and Bruce Blumberg believe the focus of the discussions should be?
On the biochemical pathways that had to be affected by some environmental factor that was producing the deformities. (Page 258-259)
24. Describe Pieter Johnson’s work and the effect it had on the investigation.
He isolated a trematode parasite in the lab and conducted a live assay on Pacific tree frog tadpoles. He was able to duplicate all of the deformities found in the field. This gave the parasite theory credibility as
the sole cause. (Page 260)
25. What was the “bad boy”?
Ribeiroia, the trematode parasite found in snails and deformed frogs. (Page 261)
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