Sánchez Salguero, Jon AndoniOtero Fuertes, María PazAlfonso Rancaño, María AmparoRamos, VitorVasconcelos, VitorAráoz, RomuloMolgó, JordiRodríguez Vieytes, MercedesBotana López, Luis Miguel2020-11-062020-11-062014Sanchez, J.A.; Otero, P.; Alfonso, A.; Ramos, V.; Vasconcelos, V.; Aráoz, R.; Molgó, J.; Vieytes, M.R.; Botana, L.M. Detection of Anatoxin-a and Three Analogs in Anabaena spp. Cultures: New Fluorescence Polarization Assay and Toxin Profile by LC-MS/MS. Toxins 2014, 6, 402-415http://hdl.handle.net/10347/23590Anatoxin-a (ATX) is a potent neurotoxin produced by several species of Anabaena spp. Cyanobacteria blooms around the world have been increasing in recent years; therefore, it is urgent to develop sensitive techniques that unequivocally confirm the presence of these toxins in fresh water and cyanobacterial samples. In addition, the identification of different ATX analogues is essential to later determine its toxicity. In this paper we designed a fluorescent polarization (FP) method to detect ATXs in water samples. A nicotinic acetylcholine receptor (nAChR) labeled with a fluorescein derivative was used to develop this assay. Data showed a direct relationship between the amount of toxin in a sample and the changes in the polarization degree of the emitted light by the labeled nAChR, indicating an interaction between the two molecules. This method was used to measure the amount of ATX in three Anabaena spp. cultures. Results indicate that it is a good method to show ATXs presence in algal samples. In order to check the toxin profile of Anabaena cultures a LC-MS/MS method was also developed. Within this new method, ATX-a, retention time (RT) 5 min, and three other molecules with a mass m/z 180.1 eluting at 4.14 min, 5.90 min and 7.14 min with MS/MS spectra characteristic of ATX toxin group not previously identified were detected in the Anabaena spp. cultures. These ATX analogues may have an important role in the toxicity of the sampleeng© 2014 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/)http://creativecommons.org/licenses/by/3.0/Anatoxin-aNicotinic acetylcholine receptorFluorescence polarizationLiquid chromatography-mass spectrometryAnabaena spp.journal article10.3390/toxins60204022072-6651open access