Featured Research

from universities, journals, and other organizations

DNA Test Solving Chesapeake's Toxic Mysteries

Date:
August 11, 2000
Source:
University Of Maryland Biotechnology Institute
Summary:
As the summer heats up Chesapeake Bay waters, a new kind of test to detect toxic marine microbes is sharpening Maryland efforts to predict fish-killing Pfiesteria. The test also helps medical studies of illness associated with the microbe.

As the summer heats up Chesapeake Bay waters, a new kind of test to detect toxic marine microbes is sharpening Maryland efforts to predict fish-killing Pfiesteria. The test also helps medical studies of illness associated with the microbe.

David Oldach of the University of Maryland Biotechnology Institute (UMBI) reports that the test, applied to samples of mud or water, rapidly identifies Pfiesteria piscicida. In 1997, the microbe was linked with major fish kills in three Maryland rivers as well as previous fish kills in North Carolina. In addition, watermen near the fish kills and laboratory workers handling Pfiesteria cultures have suffered from illness ranging from skin lesions and stomach cramps to temporary memory loss and learning impairment lasting up to seven weeks.

In a recent issue of the Proceedings of the National Academy of Sciences, Oldach writes that the test is based on a "time-tested molecular biology method used commonly in medical research." The method, called HMA, is more often used to tease ut different strains of viruses in studies of Hepatitis C, AIDS, or gene mutations linked with cancer, or genetic diseases, such as cystic fibrosis.

Oldach and colleagues at UMBI's Institute of Human Virology (IHV) applied the method to samples of water and cultures of Pfiesteria-like microbes from Maine, Maryland, and North Carolina. The result is a DNA fingerprint of Pfiesteria used in the new test. The test can be adapted to detect other toxic marine organisms, he adds.

Last year in Maryland, experiments on the new test helped show that P. piscicida existed in at least 14 rivers and increased dramatically in July and August, according to Dave Goshorn, chief of the Maryland Department of Natural Resources' (DNR) Living Resource Assessment Program. "We found that the new test works so well, we will expand from 50 to 100 testing sites in the Bay area in 2000, in addition to any fish kill sites."

The new Pfiesteria test is "simple and brilliant," comments Robert A. Venezia, director of the state Department Health and Mental Hygiene's Office of Environmental Health Coordination. "The test has heightened the Department of Natural Resources' (DNR) ability to identify fish kills and subsequently issue an advisory for the public to avoid an area or to close the river," he adds.

The chemical structure of the P. piscicada toxin is still not "fully identified," says toxicologist John D. Ramsdell, who tests samples of Pfiesteria culture on brain tissues at the Charleston, S.C. laboratory of the National Oceanographic and Atmospheric Administration. However, he comments, "The work that Dave (Oldach) is performing to get the correct toxic organism has takenus light years ahead."

Ramsdell says the toxin affects immune cells in the brain. He says such a theory explains both the human memory problems and lethargy experienced by humans who come into contact with the toxin as well as the infectious lesions in the fish. Each Pfiesteria culture produces only a miniscule amount of toxin, he says, but stimulates "tremendous linkage in cells of the nervous systems."

Ultimately, says Oldach, the most important part of the Pfiesteria story may lie in medical studies of the toxicity. He notes, "The most exciting medical aspect is that reversible cognitive deficit (short-term memory loss), identified by Lynn Gratton, a neuropsychologist at the University of Maryland School of Medicine, relates to new learning -- the actual laying down of new memories." Oldach proposes that a small molecule, basically the toxin, may be disrupting a critical function in the brain that is essential for how people learn. Ragsdell adds that, because the toxin seems to work on a unique class of receptor or sensitive cells in the brain, the greatest potential of Pfiesteria research may be in new drugs for learning disorders.

Also, the new DNA test adds precision to studies of the health symptoms of watermen by Oldach and other medical researchers in the University System of Maryland and the Johns Hopkins School of Medicine. Every two weeks, participating watermen report their symptoms and areas where they have been working on the water. Two to three times a year, they take cognitive tests of their memory and concentrating powers. The results are in turn linked with DNR environmental data, including the presence or absence of Pfiesteria in the rivers, using the new test.

There have been no major outbreaks of toxic Pfiesteria since 1997. But, Maryland's DNR continues to seek answers to such questions as how to predict new outbreaks, when does the microbe turn toxic, and what is the nature of the toxin. The DNR will continue to send water samples to Oldach' laboratory, UMBI's Center of Marine Biotechnology (COMB), the University of Maryland's Center for Environmental Studies at Horn Point, and the Aquatic Botany Laboratory at North Carolina State University in an attempt to find more answers.


Story Source:

The above story is based on materials provided by University Of Maryland Biotechnology Institute. Note: Materials may be edited for content and length.


Cite This Page:

University Of Maryland Biotechnology Institute. "DNA Test Solving Chesapeake's Toxic Mysteries." ScienceDaily. ScienceDaily, 11 August 2000. <www.sciencedaily.com/releases/2000/07/000731073145.htm>.
University Of Maryland Biotechnology Institute. (2000, August 11). DNA Test Solving Chesapeake's Toxic Mysteries. ScienceDaily. Retrieved August 1, 2014 from www.sciencedaily.com/releases/2000/07/000731073145.htm
University Of Maryland Biotechnology Institute. "DNA Test Solving Chesapeake's Toxic Mysteries." ScienceDaily. www.sciencedaily.com/releases/2000/07/000731073145.htm (accessed August 1, 2014).

Share This




More Plants & Animals News

Friday, August 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Vaccine Might Be Coming, But Where's It Been?

Ebola Vaccine Might Be Coming, But Where's It Been?

Newsy (Aug. 1, 2014) Health officials are working to fast-track a vaccine — the West-African Ebola outbreak has killed more than 700. But why didn't we already have one? Video provided by Newsy
Powered by NewsLook.com
Study Links Certain Birth Control Pills To Breast Cancer

Study Links Certain Birth Control Pills To Breast Cancer

Newsy (Aug. 1, 2014) Previous studies have made the link between birth control and breast cancer, but the latest makes the link to high-estrogen oral contraceptives. Video provided by Newsy
Powered by NewsLook.com
Visitors Feel Part of the Pack at Wolf Preserve

Visitors Feel Part of the Pack at Wolf Preserve

AP (July 31, 2014) Seacrest Wolf Preserve on the northern Florida panhandle allows more than 10,000 visitors each year to get up close and personal with Arctic and British Columbian Wolves. (July 31) Video provided by AP
Powered by NewsLook.com
Florida Panther Rebound Upsets Ranchers

Florida Panther Rebound Upsets Ranchers

AP (July 31, 2014) With Florida's panther population rebounding, some ranchers complain the protected predators are once again killing their calves. (July 31) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins