The great microbe race Pfiesteria: With lots of money for research at stake, two rival teams of scientists are pushing hard in a hunt for toxins.

October 06, 1997|By Douglas M. Birch | Douglas M. Birch,SUN STAFF

As concern about Pfiesteria's effects on human health has escalated, a race has developed between two rival teams of scientists studying these guerrilla microbes and struggling to extract their exotic poisons.

The short-term winner will be the first team to publish a description of one of Pfiesteria's toxins in a scientific journal.

"These toxins are at the basis of all therapy, all tests, of all preventive measures," says Dr. Daniel G. Baden, a toxicologist with the University of Miami, who leads one of the teams. His group includes physicians and scientists at the University of Maryland and the Johns Hopkins University medical schools and at the Center of Marine Biotechnology.

Its rival? A team led by JoAnn Burkholder, the aquatic ecologist credited with the discovery of Pfiesteria.

Burkholder, who has worked as a consultant to the state, is considered the authority on the single-celled organism, which stalks and bushwhacks fish by spewing an array of chemicals.

Burkholder's team is focusing on the water-soluble neurotoxin, which disorients fish and might cause memory problems in humans. Baden's group has concentrated its efforts on the fat-soluble toxin, which sloughs the flesh off fish.

Last week, the National Institute of Environmental Health Sciences announced that Baden's team had "isolated" or made pure extracts of the two toxins. This is the first crucial step to being able to describe, synthesize and recognize the chemical.

Burkholder shot back with e-mail to colleagues saying the institute's statement "needs to be corrected" and reminding them that her lab had already isolated those toxins. Not only that, she wrote, "we are very close to naming one," the final step in the process.

What's at stake here is the health and welfare of people who live and work along the coast, from Delaware to the Gulf of Mexico.

But that's not all. Careers hang in the balance. So does money -- lots of it, by the standards of scientific research.

Congress is poised to underwrite new Pfiesteria research in North Carolina, Virginia and Maryland at a cost of at least $6.8 million and to give the national Centers for Disease Control and Prevention another $7 million for a seven-state epidemiological study.

Grants are also being dangled by other agencies: Scientists in Baltimore have applied for up to $3.5 million from the National Institute of Environmental Health Sciences over the next five years. And that doesn't count millions of dollars in grants already allocated.

Of course, researchers say, money isn't their only -- or even their main -- concern.

"There is genuine, basic interest in the scientists here in addressing these questions," said Dr. Gerardo Vasta, a professor at the University of Maryland's Center of Marine Biotechnology in the Columbus Center. "It is a great opportunity to combine our interests and skills."

Baden goes so far as to say he doesn't really care who wins the race.

"The advantage of having more than one team working on it, you push the science forward," he says. "I will be as happy if they get the structure first.

"Ultimately, what we're trying to do is prevent human health effects and marine animal mortalities."

Don't want to rush results

In some scientific circles, it's common for researchers to agree to work in separate areas, so they don't duplicate their efforts.

That's not happening with Pfiesteria.

So the great microbe race is on. And scientists say it's likely to mean nervous days and exhausting nights in the lab.

Researchers on both sides say that while they will be pushing hard, they don't want to rush their results.

"I want to be sure it's done correctly," says Dr. John S. Ramsdell, a member of Burkholder's team who studies aquatic toxins at the National Marine Fisheries Service labs in Charleston, S.C. "I just can't see it going at a helter-skelter pace."

Toxin hunting is a process of separating the poisons from the water they are dissolved in, sort of like unmixing a cup of instant cocoa.

Basically, it works this way: Fish are put into a tank with the microbes, and the microbes go into a feeding frenzy, manufacturing their poisons. Water from the tank is poured through a special filter that concentrates the toxic materials on its surface. Then the poisons are collected. Through repeated filtrations, scientists tease out increasingly pure amounts of toxin.

"You keep eliminating material until [you] only have toxic material left," Baden says.

Once they have a pure sample, scientists can study its chemical structure using various techniques, including spectroscopy -- analyzing the light produced by burning bits of the material.

In principle, it's simple. In practice, the effort has crawled along -- scientists have been searching for these toxins for at least five years. But with worldwide attention focused on Pfiesteria, the work has a new urgency.

"It's been a difficult search principally because there's never enough material to do a proper chemical identification," Baden says.

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