Toxicity and bioaccumulation of two non-protein amino acids synthesised by cyanobacteria, β-N-Methylamino-L-alanine (BMAA) and 2,4-diaminobutyric acid (DAB), on a crop plant

Ecotoxicol Environ Saf. 2021 Jan 15:208:111515. doi: 10.1016/j.ecoenv.2020.111515. Epub 2020 Oct 21.

Abstract

In order to study the toxicity of the cyanobacterial non-protein amino acids (NPAAs) L-β-N-methylamino-L-alanine (BMAA) and its structural isomer L-2,4-diaminobutyric acid (DAB) in the forage crop plant alfalfa (Medicago sativa), seedlings were exposed to NPAA-containing media for four days. Root growth was significantly inhibited by both treatments. The content of derivatised free and protein-bound BMAA and DAB in seedlings was then analysed by LC-MS/MS. Both NPAAs were detected in free and protein-bound fractions with higher levels detected in free fractions. Compared to shoots, there was approximately tenfold more BMAA and DAB in alfalfa roots. These results suggest that NPAAs might be taken up into crop plants from contaminated irrigation water and enter the food chain. This may present an exposure pathway for NPAAs in humans.

Keywords: BMAA; Cyanobacteria; DAB; Non-protein amino acid.

MeSH terms

  • Amino Acids, Diamino / metabolism*
  • Amino Acids, Diamino / toxicity
  • Aminobutyrates / metabolism*
  • Aminobutyrates / toxicity
  • Bioaccumulation
  • Chromatography, Liquid
  • Crops, Agricultural / drug effects
  • Crops, Agricultural / metabolism*
  • Cyanobacteria / chemistry
  • Cyanobacteria Toxins
  • Humans
  • Isomerism
  • Neurotoxins / analysis
  • Seedlings / chemistry
  • Tandem Mass Spectrometry

Substances

  • Amino Acids, Diamino
  • Aminobutyrates
  • Cyanobacteria Toxins
  • Neurotoxins
  • beta-N-methylamino-L-alanine
  • 2,4-diaminobutyric acid