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Résumé:
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Anatoxin-a (ANTX) is a neurotoxin produced by several freshwater cyanobacteria and has
been implicated in the death of livestock and domestic animals from consumption of tainted
surface waters. ANTX is unstable under normal conditions and is somewhat problematic to
extract and study. Accelerated solvent extraction (ASE) combined with liquid
chromatography-mass spectrometry (LC/MS) was used to develop an efficient extraction and
analytical method for both ANTX and the more commonly encountered hepatotoxic
microcystins produced by cyanobacteria. The effects of nitrogen supply on the cellular
production and release of ANTX was investigated in Aphanizomenon issatschenkoi
(Ussaczew) Proschkina-Lavrenko (Nostocales). In contrast to the predictions of the carbonnutrient
balance hypothesis, the maximum production was observed under moderate N stress.
In addition, steady state fugacity-based models were employed to investigate ANTX’s
distribution and fate in freshwater ecosytems. ANTX was not found to be very persistent in
aquatic ecosystems and did not appear to bioaccumulate in fish, at least not from the
dissolved phase. |
