MALDI-TOF-MS detection of the low molecular weight neurotoxins anatoxin-a and homoanatoxin-a on lyophilized and fresh filaments of axenic Oscillatoria strains

• Published in: Toxicon (Oxford) 2008-06, Vol.51 (7), p.1308-1315
• Main Authors: Aráoz, Rómulo, Guérineau, Vincent, Rippka, Rosmarie, Palibroda, Nicolae, Herdman, Michael, Laprevote, Olivier, von Döhren, Hans, de Marsac, Nicole Tandeau, Erhard, Marcel
• Format: Article
• Language: English
• Subjects: Anabaena; Anabaena - chemistry; Anabaena - metabolism; Anatoxin-a; Animal poisons toxicology. Antivenoms; Animals; Bacterial Toxins; Bacterial Toxins - analysis; Bacterial Toxins - chemistry; Bacteriology; Bicyclo Compounds, Heterocyclic; Biological and medical sciences; Bridged Bicyclo Compounds, Heterocyclic - analysis; Bridged Bicyclo Compounds, Heterocyclic - chemistry; Cellular Biology; Cyanobacteria; Cyanotoxins; Fundamental and applied biological sciences. Psychology; Gas Chromatography-Mass Spectrometry; Gas Chromatography-Mass Spectrometry - methods; Homoanatoxin-a; Life Sciences; MALDI-TOF-MS; Medical sciences; Microbiology; Molecular Weight; Neurons and Cognition; Neurotoxins; Neurotoxins - analysis; Neurotoxins - chemistry; Oscillatoria; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - methods; Toxicology; Tropanes; Tropanes - analysis; Tropanes - chemistry
• ISSN: 0041-0101; 1879-3150; 0041-0101
• DOI: 10.1016/j.toxicon.2008.02.018

Anatoxin-a (ANTX) and homoanatoxin-a (HANTX) are low molecular weight neurotoxic secondary amines of 165 and 179 Da, respectively. We applied matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) for the detection of ANTX and HANTX directly on lyophilized and fresh filaments of axenic strains of the genus Oscillatoria, using 2,5-dihydroxybenzoic acid as matrix and purified ANTX and HANTX as references. To counteract the span of low molecular mass ions (< m/ z 1000) generated by the matrix, we induced the matrix-suppression effect to obtain high quality ANTX/HANTX MALDI signals. MALDI desorption/ionization of the matrix-ANTX and the matrix-HANTX generated protonated molecules [M+H] + at m/ z 166.12322 and 180.1372, respectively. The masses obtained from the analysis of lyophilized filaments of the ANTX-producer Oscillatoria sp. strain PCC 9240 ( m/ z 166.15) and of fresh filaments of the HANTX-producers Oscillatoria sp. strains PCC 6506 ( m/ z 180.1375), PCC 9029 ( m/ z 180.1334) and PCC 10111 ( m/ z 180.13996) corresponded to the protonated molecular ions of ANTX and HANTX, respectively. Therefore, the application of MALDI-TOF-MS for the detection of cyanobacterial anatoxins in clonal and axenic strains of the cyanobacterial culture collections worldwide may help to assess ANTX/HANTX incidence among cyanobacteria.