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Soil & Water Conservation Society of Metro Halifax (SWCSMH)
July 26, 2006 
Contents:
Diverse taxa of cyanobacteria produce ß-N-methylamino-L-alanine (BMAA), a neurotoxic amino acid
Diverse taxa of cyanobacteria produce ß-N-methylamino-L-alanine (BMAA), a neurotoxic amino acid
(cf. Cox et al., 2005., Proc. the National Academy of Sciences of the USA [in HTML] [in PDF])
Abstract:
Cyanobacteria can generate molecules hazardous to human health, but production of the known cyanotoxins is taxonomically sporadic. For example, members of a few genera produce hepatotoxic microcystins, whereas production of hepatotoxic nodularins appears to be limited to a single genus. Production of known neurotoxins has also been considered phylogenetically unpredictable. We report here that a single neurotoxin, ß-N-methylamino-L-alanine, may be produced by all known groups of cyanobacteria, including cyanobacterial symbionts and free-living cyanobacteria. The ubiquity of cyanobacteria in terrestrial, as well as freshwater, brackish, and marine environments, suggests a potential for wide-spread human exposure.
Discussion (part):
The recent hypothesis that BMAA accumulates in proteins, which collectively function as an endogenous neurotoxic reservoir within the human body, and then is slowly released through time as these proteins are metabolized suggests that possible health consequences of chronic exposure to low doses of BMAA deserve further investigation. It may now be prudent to monitor BMAA concentrations in drinking waters contaminated by cyanobacterial blooms. BMAA concentrations should also be monitored within invertebrates, fish, or grazing animals used for human consumption that either directly consume cyanobacteria or forage on plants or prey that may have accumulated cyanobacteria-produced BMAA. Given the global importance of marine cyanobacterial blooms, such as those generated by iron-laden dust in the Atlantic and Pacific Oceans, a broader analysis of the production and fate of BMAA in marine ecosystems is also needed.
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