Distinguishing the cyanobacterial neurotoxin β-N-methylamino-L-alanine (BMAA) from other diamino acids

Institute for Ethnomedicine, Box 3464, Jackson, WY 83001, USA.
Toxicon (Impact Factor: 2.49). 02/2011; 57(5):730-8. DOI: 10.1016/j.toxicon.2011.02.005
Source: PubMed

ABSTRACT β-N-methylamino-L-alanine (BMAA) is produced by diverse taxa of cyanobacteria, and has been detected by many investigators who have searched for it in cyanobacterial blooms, cultures and collections. Although BMAA is distinguishable from proteinogenic amino acids and its isomer 2,4-DAB using standard chromatographic and mass spectroscopy techniques routinely used for the analysis of amino acids, we studied whether BMAA could be reliably distinguished from other diamino acids, particularly 2,6-diaminopimelic acid which has been isolated from the cell walls of many bacterial species. We used HPLC-FD, UHPLC-UV, UHPLC-MS, and triple quadrupole tandem mass spectrometry (UHPLC-MS/MS) to differentiate BMAA from the diamino acids 2,6-diaminopimelic acid, N-2(amino)ethylglycine, lysine, ornithine, 2,4-diaminosuccinic acid, homocystine, cystine, tryptophan, as well as other amino acids including asparagine, glutamine, and methionine methylsulfonium.

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Available from: Timothy G Downing, Oct 30, 2014
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    • "> 119.1) which is common for AEG, BMAA and DAB; (459.18 > 258.1) which is the specific fragment for BMAA; (459.18 > 188.1) specific for DAB (Spa´cˇil et al., 2010), (459.18 > 214.1) specific for AEG (Banack et al., 2011) and (462.2 > 122.1) specific for D 3 -BMAA (Fig. 1). Collision energy was 26 V for all transitions. "
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    ABSTRACT: Amyotrophic lateral sclerosis (ALS) is an extremely devastating neurodegenerative disease with an obscure etiology. The amino acid β-N-methyl-L-alanine (BMAA) produced by globally widespread phytoplankton has been implicated in the etiology of human motor neuron diseases. BMAA was recently proven to be present in Baltic Sea food webs, ranging from plankton to larger Baltic Sea organisms, some serving as important food items (fish) for humans. To test whether exposure to BMAA in a Baltic Sea setting is reflected in humans, blood and cerebrospinal fluid (CSF) from individuals suffering from ALS were analyzed, together with sex and age matched individuals not inflicted with ALS. UPLC-MS/MS and multiple reaction monitoring (MRM), in conjuntion with diagnostic transitions revealed BMAA in three (12%) of the totally 25 Swedish individuals tested, with no preference for those suffering from ALS. The three BMAA positive samples were all retrieved from the CSF, while BMAA was not detected in blood. The data show that BMAA, potentially originating from Baltic Sea phytoplankton, may reach the human central nervous system, but do not lend support to the notion that BMAA is resident specifically in ALS-patients. However, while dietary exposure to BMAA may be intermittent and, if so, difficult to detect, our data provide the first demonstration of BMAA in the central nervous system of human individuals ante mortem quantified with UPLC-MS/MS, and therefore calls for extended research efforts. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.
    Neuroscience 02/2015; 6. DOI:10.1016/j.neuroscience.2015.02.032 · 3.36 Impact Factor
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    • "Formic acid (>98% ACS grade) was obtained from EMD (Gibbstown, NJ, USA). The internal standard, d3-BMAA, was synthesized in-house following previously outlined procedures with some modifications [17,26,27]. In a round bottom flask a solution of d3-methyl amine hydrochloric acid (1 g in 4 mL of water) was cooled to 4°C. "
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    ABSTRACT: Over the last decade the amino acid beta-N-methylamino-L-alanine (BMAA) has come under intense scrutiny. International laboratory and epidemiological research continues to support the hypothesis that environmental exposure to BMAA (e.g., through dietary practices, water supply) can promote the risk of various neurodegenerative diseases. A wide variety of cyanobacteria spp. have previously been reported to produce BMAA, with production levels dependent upon species, strain and environmental conditions. Since spirulina (Arthrospira spp.) is a member of the cyanobacteria phylum frequently consumed via dietary supplements, the presence of BMAA in such products may have public health implications. In the current work, we have analyzed ten spirulina-containing samples for the presence of BMAA; six pure spirulina samples from two separate raw materials suppliers, and four commercially-available multi-ingredient products containing 1.45 g of spirulina per 8.5 g serving. Because of controversy surrounding the measurement of BMAA, we have used two complementary liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods: one based on reversed phase LC (RPLC) with derivatization and the other based on hydrophilic interaction LC (HILIC). Potential matrix effects were corrected for by internal standardization using a stable isotope labeled BMAA standard. BMAA was not detected at low limits of detection (80 ng/g dry weight) in any of these product samples. Although these results are reassuring, BMAA analyses should be conducted on a wider sample selection and, perhaps, as part of ongoing spirulina production quality control testing and specifications.
    Aquatic Biosystems 08/2014; 10(5):1-7. DOI:10.1186/2046-9063-10-5
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    • "The resultant product ions were detected within the third quadrupole and their relative abundances were quantified. Chromatographic separation with unique retention times, and unique product ions, and ion ratios confirmed the identification of BMAA relative to any possible isomers [2,4-diaminobutryic acid (DAB) and N-(2-aminoethyl)glycine][20]. "
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    ABSTRACT: Mechanisms of protein misfolding are of increasing interest in the aetiology of neurodegenerative diseases characterized by protein aggregation and tangles including Amyotrophic Lateral Sclerosis (ALS), Alzheimer's disease (AD), Parkinson's disease (PD), Lewy Body Dementia (LBD), and Progressive Supranuclear Palsy (PSP). Some forms of neurodegenerative illness are associated with mutations in genes which control assembly of disease related proteins. For example, the mouse sticky mutation sti, which results in undetected mischarging of tRNA(Ala) with serine resulting in the substitution of serine for alanine in proteins causes cerebellar Purkinje cell loss and ataxia in laboratory animals. Replacement of serine 422 with glutamic acid in tau increases the propensity of tau aggregation associated with neurodegeneration. However, the possibility that environmental factors can trigger abnormal folding in proteins remains relatively unexplored. We here report that a non-protein amino acid, β-N-methylamino-L-alanine (BMAA), can be misincorporated in place of l-serine into human proteins. We also report that this misincorporation can be inhibited by l-serine. Misincorporation of BMAA into human neuroproteins may shed light on putative associations between human exposure to BMAA produced by cyanobacteria and an increased incidence of ALS.
    PLoS ONE 09/2013; 8(9):e75376. DOI:10.1371/journal.pone.0075376 · 3.23 Impact Factor
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