Medical Mystery: Does Cyanobacteria play a role in brain diseases like Alzheimer's?
Florida has become the stage for a drama involving research into a possible link between brain diseases like Alzheimer’s and a toxin produced by common algae. The story so far:
Cyanobacteria, the blue-green algae known as pond scum, produce a toxin called BMAA. Does it play a role in brain diseases like Alzheimer's? [Photo: iStockphoto]
Act 1 - Batty in the South Pacific
After World War II, the native Chamorro people on the island of Guam were struck by a strange neurological disease, a devastating complex of Lou Gehrig's disease with Parkinson's symptoms and an Alzheimer's-like dementia. It killed a quarter of adult Chamorros.
Ethnobotanist Paul Cox found a link between the BMAA neurotoxin and brain disease. Florida scientists advanced his hypothesis while Florida private donors supported the research and created the Institute for Ethnomedicine in Jackson Hole, Wyo., for him to continue his studies. "Florida has been the major incubator of the thing, the major funder and the major intellectual driver." [Photo: Paul Alan Cox]
The National Institutes of Health opened a research station, and researchers began focusing on the seed of a primitive, chemical-rich plant called the cycad. In the cycad's roots, cyanobacteria, the blue-green algae that most of us know as pond scum, produced a toxin called BMAA that damages nerve cells and was taken up into the cycad's seeds.
Researchers knew Chamorros ate flour that was ground from cycad seed but dropped that line of investigation after determining that the concentrations of BMAA in the flour were so small that the Chamorros would have to eat truckloads of it to get sick.
That was until 2002, when two researchers published a paper proposing an answer to the riddle. One was Oliver Sacks, the scientist on whom the movie Awakenings was based. The other was Paul Cox, an ethnobotanist — someone who studies the relationships between indigenous people and the plants around them. Cox also was a former Mormon missionary named by Time magazine as one of its "Heroes of Medicine" in 1997.
Cox and Sacks argued that fruit bats on Guam ate the cycad seeds and thereby "biomagnified" — concentrated — the neurotoxin in their bodies. The Chamorros cooked the bats whole in coconut milk and ate them as a delicacy and so ended up getting a whopping dose of BMAA big enough to cause brain disease, the two suggested. Cox also observed that the epidemic had dwindled as the bats went nearly extinct.
Fruit bats in Guam feasted on cycad seeds, magnifying the neurotoxin BMAA. The Chamorro people in turn ate the bats as a delicacy. [Photo: Paul Alan Cox]