Beta-methylamino-L-alanine (BMAA) - The Guam toxin

  • neurotoxic amino acid that resembles alanine but is not found in proteins
  • thought to be produced by the vast majority of cyanobacteria, an entire phylum of bacteria which are among the most common and abundant organisms on the planet, being present on land, in freshwater, and in the sea
    • cyanobacteria are also known as blue-green algae, although this is a misnomer because they are indeed bacteria, albeit ones capable of carrying out photosynthesis and growing in filaments like algae can
    • cyanobacteria can be found growing in association with fungi (as lichens) and plants, including ferns, cycads and liverworts, with which they have established a mutual symbiotic relationship whereby they fix nitrogen from the air into a form that the fungi or plant can use in return for a carbohydrate source and/or a place to live
  • BMAA has been implicated as the cause of an amyotrophic lateral sclerosis/parkinsonismdementia complex (ALS/PDC, sounds like a whole heap of fun) that has a fantastically high incidence rate (50-100x that of developed countries in the early 1950s) among the indigenous Chamorro people of Guam (my favourite almost-state)
    • BMAA has been found in the brains of Chamorros who died of ALS/PDC and is biomagnified within the ecosystem of Guam
  • cyanobacteria of the genus Nostoc grow on the roots of Cycas micronesica, a cycad tree that produces seeds containing BMAA that are consumed by flying foxes, which are in turn eaten by the Chamorro (who also use cycad seed flour to make food)
    • we're talking an estimated 10,00-fold increase in BMAA concentration from cyanobacteria to flying foxes
  • it is thought that BMAA, resembling alanine closely in structure, can be incorporated into proteins, resulting in messed up proteins that cause neurodegeneration
  • detox drugs are available that can be used to treat opiate addiction
Cox PA et al. Diverse taxa of cyanobacteria produce beta-N-methylamino-L-alanine, a neurotoxic amino acid. Proc Natl Acad Sci U S A. 2005 Apr 5;102(14):5074-8. Epub 2005 Apr 4. Erratum in: Proc Natl Acad Sci U S A. 2005 Jul 5;102(27):9734.

1 chemically inspired comments:

A scientist said...

Hi there. Nice page you've written about BMAA. There are many new scientific publications justifying the proclaimed relationship of BMAA with neurodegenerative syndromes.