Cyanobacteria linked to neurological disease

HONOLULU - Cyanobacteria throughout the world may produce a toxin linked to certain types of neurological disease, an international team of researchers announced today in the online edition of the Proceedings of the National Academy of Sciences. Samples of cyanobacteria collected from diverse habitats produced BMAA, a toxic amino acid.

"We surveyed 30 cultures of cyanobacteria maintained at Stockholm University in Sweden, the University of Dundee in Scotland, and the University of Hawai'i," explained Dr. Paul Alan Cox, Director of the Institute for Ethnomedicine at Kauai's National Tropical Botanical Garden. "Ninety-five percent of the cyanobacterial genera produce BMAA."

University of Hawai'i researchers Robert Bidigare and Georgia Tien of the Center for Marine Microbial Ecology & Diversity (CMMED) collaborated with Cox on this research project by isolating and providing blue green algal clones from their extensive culture collection. CMMED is the proprietor of the Patterson Cyanobacteria Collection, the largest collection of cyanobacterial strains in the world. About 20 years ago, Dr. Greg Patterson, formally of UH, assembled this collection of greater than 2,000 strains, representing most continents.

"The value of this collection cannot be underestimated. For example, cryptophycin, a potent anticancer agent, was isolated from a Nostoc sp. strain in the Patterson Culture Collection," said Bidigare.

"Currently due to considerations for ecological protection and sensitivity to bioprospecting and native rights, a field collection of this geographic scope and magnitude can no longer be assembled. Consequently this is a unique and valuable resource for renewable energy sources exploration, experimental pharmacology, marine natural products, including phytotoxins, and biotechnology applications," said Bidigare.

Until recently, BMAA was known only from cycads, plants of warm areas of the world that are sometimes eaten by indigenous people such as the Chamorro of Guam. Researchers have proposed a link between BMAA and an ALS-like disease suffered by the Chamorro people. Cox, Canadian scientist Dr. Susan Murch, and Dr. Sandra Banack at California State University, Fullerton, found that BMAA is produced by cyanobacteria resident in the roots of the cycad trees.

Interest in the hypothesis increased when BMAA was found in the brain tissues of several Alzheimer's disease patients in Canada. This discovery spurred cyanobacterial experts Bidigare, Dr. Birgitta Bergman at Stockholm University, and Dr. Geoffrey Codd at the University of Dundee to collaborate with Cox's team to see if the toxin is produced by other forms of cyanobacteria. Cyanobacteria are common in oceans, lakes, and even soils throughout the world.

The Proceedings of the National Academy of Sciences' article includes a satellite photograph of a 100-mile long bloom of cyanobacteria off the Florida coast. Although cyanobacteria are known to produce a variety of hazardous molecules, researchers say that this is the first indication that diverse species of cyanobacteria produce the same toxin.

The study raises more questions than answers, scientists caution. The link between BMAA and neurological disease remains an unproven hypothesis, Cox explains. This new study merely indicates that human exposure to BMAA may be possible in many places throughout the world. Researchers suggest that BMAA should be monitored in reservoirs and other water supplies contaminated by cyanobacteria.

Images are available for download at http://www.soest.hawaii.edu/SOEST_News/PressReleases/Bidigare2005/

Contact:
Dr. Robert Bidigare, University of Hawai'i at Manoa
Tel.: (808) 956-8146
Fax: (808) 956-5308
Email: bidigare@hawaii.edu

Research Article Citation:
Proceedings of the National Academy of Sciences, April 5, 2005, vol. 102, no. 14

Diverse taxa of cyanobacteria produce B-N-methylamino-L-alanine, a neurotoxic amino acid
Paul Alan Cox, Sandra Anne Banack, Susan J. Murch, Ulla Rasmussen, Georgia Tien, Robert Richard Bidigare, James S. Metcalf, Louise F. Morrison, Geoffrey A. Codd, and Birgitta Bergman

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