Probe detects Pfiesteria in Va.

Researchers at Institute of Marine Science find diagnostic procedure

January 11, 2001|By ASCRIBE NEWS SERVICE

GLOUCESTER POINT, Va. - Virginia Institute of Marine Science scientists Kimberly Reece and Nancy Stokes have developed molecular diagnostic tools to detect Pfiesteria piscicida and related organisms in water samples.

The tools were developed using funds for Pfiesteria research provided to VIMS by the Virginia General Assembly and a grant from Environmental Protection Agency. The researchers used the tools to look for Pfiesteria in water samples collected during September and October by the Department of Environmental Quality.

Results showed that Pfiesteria piscicida and related organisms, were present at several locations in Virginia waters. Pfiesteria piscicida was found at 11 sites, including Pocomoke River, Occohannock Creek and Onancock Creek on the Eastern Shore and in the Great Wicomico, York and Coan Rivers.

`Not surprised'

"We were not surprised to find these organisms." said Reece. "Because Pfiesteria has been found in Maryland waters, it is not unexpected that we've now found it in Virginia waters - especially because of this sophisticated new test which is more sensitive than tests we used in the past."

Eugene Burreson, Director for Research and Advisory Services at VIMS said, "This is only one component of a large VIMS Pfiesteria research program funded by the General Assembly. The results are important for Virginia because these diagnostic tools will be used routinely next year in the Pfiesteria monitoring programs that are coordinated by DEQ and the health studies conducted by Virginia Commonwealth University and the Virginia Department of Health."

DNA detectors

Reece and Stokes developed primers for the polymerase chain reaction and DNA probes that specifically detect either Pfiesteria piscicida. Primers and probes are small pieces of DNA that are identified as being unique to a specific organism. Using these molecular tools, researchers can detect the DNA of targeted organisms extracted from water samples.

Reece's lab employed polymerase probes to detect the DNA of Pfiesteria. The identity of each organism was confirmed through DNA fingerprinting and DNA sequencing.

These tests detect the presence of DNA from Pfiesteria piscicida. Reece emphasizes that the tests do not determine absolute abundance or toxicity of these organisms. There is no evidence, from fish kills or health reports, that the organisms found are expressing toxicity.

Dr. Burreson said, "We are now in the process of expanding these techniques and acquiring equipment that will also enable us to measure the abundance of these organisms in water samples. Molecular diagnostics such as these, also enhance our other studies by providing new tools to examine the life cycle of Pfiesteria and other aspects of its biology."

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