Analysis, occurrence, and toxicity of ß-methylaminoalanine (BMAA)

A risk for the consumer?

image of Analysis, occurrence, and toxicity of ß-methylaminoalanine (BMAA)

In 2005 an international research team reported that cyanobacteria living in symbiosis with plants or living free in lakes and oceans are able to produce the non-protein amino acid -methylaminoalanine, also known as BMAA. Some years earlier the American scientists in this team had reported that BMAA could be found not only in the brain from diseased patients of the Chamorro people on Guam having the neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and Parkinsons dementia (PD), but also in two patients with Alzheimers disease in Canada. A very high incidence of ALS and PD among the Chamorro people had been known since after the Second World War and had been linked to the use of flour prepared from the seeds of the local cycad tree, which had been shown to contain BMAA. As surface water is frequently purified and used as drinking water, it was hypothesised that low level of contamination of drinking water with BMAA from the cyanobacteria might reach the human brain and over time result in neurodegenerative disease. This reports aimed at scrutinizing this hypothesis, and concludes that BMAA is unlikely to occur in drinking water and be responsible for these neurological diseases in the Western World.



Is BMAA produced by cyanobacteria

In 2003 Cox and coworkers found BMAA to be present in cyanobacteria of the strain Nostoc, which live in symbiosis with the coralloid roots of the cycad (Cox et al, 2003). Pursuing this line of research they continued to analyse presence of BMAA in 30 different species or strains of freeliving cyanobacteria and concluded that BMAA was present in free form in 27 of these species or strains in amounts varying from 3 – 6478 microg/ g dry weight, and in bound form in 24 species or strains in amounts varying from 4- 5415 microg/g dry weight (Cox et al, 2005). According to Cox (2005) the presence of BMAA in cycads could be explained by the symbiosis these plants have with cyanobacteria. It was proposed that BMAA is produced by cyanobacteria infecting the coralloid roots of cycad trees as symbionts. BMAA is then transferred to the cycad where higher concentrations can be reached. The accumulation when going from one trophic level to another could be 100-fold. The biomagnification of BMAA through the chain cyanobacteria – cycads – flying foxes – humans could be the explanation for the high incidence of ALS-PDC on Guam and neighboring islands, according to Cox et al. (2005).


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