USGS - science for a changing world

Biology

Environmental Toxicology
Amphibians

Samples of genetics and genomics research from the USGS Biological Resources Discipline about the environmental toxicology of amphibians.


Does Pesticide Exposure Disrupt the Innate Immunity of Frogs?
Northern leopard frogs (Rana pipiens) at research laboratory. Photo credit: L. Robertson, Genomics Lab, Aquatic Ecology Branch, Leetown Science Center
Northern leopard frogs (Rana pipiens) at research laboratory. Photo credit: L. Robertson, Genomics Lab, Aquatic Ecology Branch, Leetown Science Center
Little frogs (Rana sp.) at research laboratory. Photo credit: L. Robertson, Genomics Lab, Aquatic Ecology Branch, Leetown Science Center
Little frogs (Rana sp.) at research laboratory. Photo credit: L. Robertson, Genomics Lab, Aquatic Ecology Branch, Leetown Science Center

Frogs secrete a potent mixture of antimicrobial peptides from glands in the skin that protect against a wide variety of pathogens.  Environmental contaminants may disrupt the expression of these peptides.  We are developing methodology to collect skin secretions and measure the abundance of the antimicrobial peptides and will use these techniques to assess the effects of pesticide exposure on the expression of antimicrobial peptides both in the lab and in an endangered frog species in the wild.

For more information contact Laura S. Robertson, Leetown Science Center.

Wood Frogs (Rana sylvatica)
Wood frog (Rana sylvatica). Photo credit: ARMI National Atlas for Amphibian Distributions, USGS Patuxent Wildlife Research Center
Wood frog (Rana sylvatica). Photo credit: ARMI National Atlas for Amphibian Distributions, USGS Patuxent Wildlife Research Center
Flow cytometric histograms overlayed to show typical DNA integrity measured using the DNA stain propidium iodide. Photo credit: USGS
Flow cytometric histograms overlayed to show typical DNA integrity measured using the DNA stain propidium iodide. Photo credit: USGS. Larger view
One of the pond sites sampled in the spring for wood frogs at the Kenai National Wildlife Refuge. Photo credit: USGS
One of the pond sites sampled in the spring for wood frogs at the Kenai National Wildlife Refuge. Photo credit: USGS

National Wetlands Research Center (NWRC) has partnered with the U.S. Fish and Wildlife Service (USFWS) in Anchorage, AK, to investigate possible cytogenetic impacts of contaminants and environmental factors on wood frogs at the Kenai National Wildlife Refuge (KNWR).  Methods for handling samples were developed, and protocols were optimized for assessing blood cell biomakers:

  • DNA integrity
  • DNA repair protein (DNA PKcs protein)
  • programmed cell death (caspase 3)

The biomarkers are evolutionarily conserved and should be applicable with any anuran species.

For more information contact Jill A. Jenkins, National Wetlands Research Center.

 

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