The discovery of BMAA, and examples of biomagnification and protein incorporation involving other non-protein amino acids

Because of the similarity of ALS/PDC symptoms to those of the paralytic disease lathyrism, cycad seeds from Guam were analyzed for the presence of the non-protein amino acid b-ODAP, which is known to cause lathyrism. Although b-ODAP was not detected, a novel non-protein amino acid, now known as BMAA, was isolated. Primates are more sensitive to BMAA than rodents. It is possible that BMAA when ingested at a low concentration over a long period might be responsible for ALS/PDC. Some non-protein amino acids, including domoic acid and indospicine, are known to be biomagnified. Other non-protein amino acids including azetidine-2-carboxylic acid, canavanine, and selenium containing analogues of cystine and methionine have been shown to be misincorporated into proteins. Perhaps BMAA will not be the only nonprotein amino acid that will be found in the brain tissues of those who died of a neurological disease.