close this panel. Evidence suggests, however, that R. ondatrae may have been involved in observed malformations. Limb deformities as an emerging parasitic disease in amphibians: Evidence from museum specimens and resurvey data. ]: 40th American Society for Cell Biology Annual Meeting, December 9-13, 2000, San Francisco, Calif., Abstract no. Chemical combinations may be mixtures of natural and human-made organic chemicals, each of which is harmless on its own but toxic when combined (Burkhart and others, 2000). doi: 10.1016/0043-1354(74)90041-4. A central Minnesota site was studied beginning in 1996 and continuing to the present as part of our investigation. Studies in Canada show a relation between the percentage of malformed frogs and pesticide use (Ouellet and others, 1997; Bishop and others, 1999). We determined that we can use XAD-2 resin in a solid-phase extraction procedure to obtain sufficient quantities of the purified chemical. Field investigations in malformed frogs in Minnesota 1993 1997. Reports. They also found low concentrations of some minerals (sodium, potassium) in some of these ponds where estrogens were found and suggested that this combination of factors may be related to frog malformation at sites where parasites were not found in malformed frogs.Sutherland, D., 2001, Parasites of North American Anurans: in Lannoo, M.J., ed., Status and Conservation of United States Amphibians Volume 1: Conservation Essays, Berkeley, Calif. University of California Press, in press.The amount of ultraviolet (UV) light reaching the Earth’s surface is increasing with time, and current amounts of UV radiation have been shown to cause malformations in frogs in the laboratory (Hays and others, 1996; Ankley and others, 1998).
Although normally associated with sexual development, estrogens at high concentrations also can affect limb development (Hayes, 2000).
Substances were eluted from the XAD-2 resin by sequential elution with methanol, acetone, hexane, and methylene chloride, concentrated by rotor evaporation. Geologic Atlas - 13 County.
We have positively identified the most abundant of these to be nonylphenol polyethylene glycol (n=2-13) using various mass spectroscopic methods, including gas chromatography (GC) electron impact (EI)-MS and by retention time and single-ion monitoring on HPLC ES-MSMS in comparison to authentic standards. Pollution Control Agency: An Inventory of Its Helgen (Judy) Files : gr01081: Files of Judy Helgen, Minnesota Pollution Control Agency [MPCA] biologist from 1989 through 2002. 5. The activity profile was used to guide the fractionation. Assistance #CD985060-01. In contrast, during 1996-97 Hoppe (2000) found that 2.3 percent of 2,548 frogs from those same nine sites were malformed (site-specific malformation percentages ranged from 0 to 9.4).
Thus, the high frequency of BT induction in response to exposure to TTNPB is consistent with the conclusion that BTs are diagnostic of exposure to a retinoid.Although malformed frogs have been widely studied since 1995, continued annual studies of individual sites to reveal malformation recurrence and impacts on frog populations are not common. Scientist Judy Helgen from the Minnesota Pollution Control Agency (MPCA) began to wonder what else we might find if we looked in our back … The Minnesota Pollution Control Agency (MPCA) collects data on businesses that generate or transport hazardous waste. and Bridges, C.M., 2001, Evaluation of toxicity of composite environmental contaminants from sites of amphibian deformity in central Minnesota: Final Report to the Minnesota Pollution Control Agency, February 9, 2001, 26 p.Hays, J.B., Blaustein, A.R., Kiesecker, J.M., Hoffman, P.D., Pandelova, I., Coyle, D., and Richardson, T., 1996, Developmental responses of amphibians to solar and artificial UVB sources: a comparative study: Photochemistry and Photobiology, v. 64, p. 449-456.Burkhart, J.G., Gallagher, K., Fort, D.J., Propst, T.L., and Helgen, J.C., 1998, Evidence for potentiation among environmental factors that contribute to malformations in frogs: Proceedings of the Society of Environmental Toxicology and Chemistry 18th Annual Meeting, Charlotte, N.C., November 15-19, 1998, p. 117.Harfenist, A., Power, K., Clark, L., and Peakall, D.B., 1989, A review and evaluation of the amphibian toxicological literature: Canadian Wildlife Service Technical Report Series no. The effect of trematode infection on amphibian limb development and survivorship. Exposure during stages 52/53 induces the loss of more distal limb structures (lower leg and foot), and beyond stages 53, TTNPB exposure affects only digit development. We have found such an activity, and have made significant progress in purifying the chemical that is responsible for this activity.
Welcome to the new Frogs on the Net section with more and updated links for your information, education and enjoyment. American Scientist 92: 138-147.Blaustein, A. R. and Johnson, P. T. J. 2004.