November 4, 1999

UMBI WORKSHOP SHARPENS BIOTECH FOCUS ON PFIESTERIA

BALTIMORE, Md.--Pfiesteria researchers will now launch intense biotechnology studies of why the toxic microorganism "decides" to bloom in rivers and what triggers its toxicity, according to a new report from an experts workshop held at the Center of Marine Biotechnology (COMB), part of the University of Maryland Biotechnology Institute.

Keiko Saito, research associate, checks Pfiesteria sample collection in a unique biosafety laboratory at the UMBI's Center of Marine Biotechnology (for copy of photo, call 301.403.0511)

Leading researchers from nearly 20 research institutions attended the workshop, "Molecular Approaches for Identification and Environmental Detection of Pfiesteria piscicida and Pfiesteria-like Dinoflagellates." Deploying new molecular probes to detect Pfiesteria took center stage in the discussions, says co-organizer Gerardo Vasta, COMB professor of biochemistry and immunology. "The question was can we make them better? Yes, we definitely can."

Yonathan Zohar, COMB director, says, "By bringing together the best scientists in the world on this topic, we were able to reach a consensus to work together to find the best molecular solutions." Zohar adds that, following the 1997 fish kills and health problems along some Maryland rivers associated with Pfiesteria, scientists needed to first concentrate on setting up criteria and analytical methods.

At COMB, studies of the interaction of fish and Pfiesteria helped the researchers develop both DNA and molecular probes that very accurately identify different of toxic dinoflagellates, the microbial group that includes Pfiesteria. Zohar says, "Extensive collections of Pfiesteria and similar microbes from sites of fish kills now give researchers a unique combination of expertise on both the molecular biology of the microbes and relevant fish physiology."

COMB houses the only biosafety level-3 laboratory in Maryland for growing and maintaining toxic life stages of Pfiesteria induced by fish. The BS-3 designation, by the Centers for Disease Control and Prevention, is second only in safe containment requirements to BS level-4. BS-3 laboratories are defined by research on disease agents that, if inhaled, may cause serious or potentially lethal disease.

"Up to this point, we have spent a lot of time on Pfiesteria strains and other dinoflagellate species--collecting them from different sites of outbreaks, cleaning the cultures and developing a working culture collection in our biosafety lab," Zohar says. COMB is now equipped, he adds for "fish in a bottle" studies--interaction of fish and pure cultures of Pfiesteria under toxic and non-toxic conditions. Water samples from COMB's studies are also shared with the University of Maryland School of Medicine in Baltimore.

Pfiesteria piscicida has been implicated in the 1997 fish kills in Maryland, as well as in North Carolina and Delaware. Researchers say it is a difficult microbe to identify sometimes because it may have over a dozen different stages--some plant-like, some animal-like. Researchers agree that Pfiesteria is a natural part of the marine ecology. But, under some conditions, it can become harmful to fish and pose some health problems for humans.

To develop probes for Pfiesteria, Vasta and co-workers at COMB benefited from their six previous years studying different strains of a related pathogen, the cause of "Dermo" disease in oysters. "When the outbreaks of Pfiesteria happened in the summer of '97, we were all geared up and ready. Now, with the probes, it is quite likely that new samples of Pfiesteria won't be genetically identical, that is different strains with different toxicities will be found in the environment," says Vasta.

In 1998, the National Oceanic and Atmospheric Administration (NOAA) and the National Institute for Environmental Health provided almost $4 million to COMB to identify and study the microbe and help prevent future outbreaks, notes Zohar. "Because the federal government has invested in COMB we are providing leadership to help researchers exchange information and share techniques for molecular identification." The workshop, September 1-2, 1999, was sponsored by NOAA and co-organized by Vasta, Wayne Litaker of the University of North Carolina at Chapel Hill, and Christopher Scholin of the Monterey Bay Aquarium Research Institute, Monterey, California.

Donald M. Anderson, senior scientist at the Woods Hole Oceanographic Institution and a leading expert on harmful marine organisms, comments, "The workshop showed how remarkably fast things have been done in a short time." He said researchers still need to obtain a pure sample of the Pfiesteria toxin in order to develop an antibody for quickly detecting its presence in local waters. Scientists also reported at the COMB workshop that they do not know if a Pfiesteria toxin associated with human health problems is the same toxin that kills fish. They also don't yet know the molecular and cellular mechanisms of the toxicity, says Zohar.

A summary of the workshop report will be available from Gerardo Vasta 410.234.8826.