title: High diversity of microcystins in a Microcystis bloom from an Algerian lake.
abstract: Microcystins (MCs) are cyanobacterial heptapeptides, produced by several genera and species of cyanobacteria, which have been involved in poisoning of animals throughout the world and have also been implicated in human health problems. They are regarded as the most frequently occurring and widespread of the cyanotoxins, with more than 100 MC variants reported to date including the present study. The lake des Oiseaux is a shallow permanent freshwater lake located in north-eastern Algeria. It is an important natural reserve playing a major role for the migratory birds after the crossing of the Mediterranean Sea and from the Sahara desert. In recent years, possibly related to increased eutrophication of the lake, massive blooms of cyanobacteria identified as Microcystis spp. have been observed. A bloom sample collected in September 2013 was analyzed by the serine/threonine phosphatase PP2A inhibition assay and liquid chromatography-mass spectrometry to determine respectively, the total concentration of MCs and the different variants of these toxins present. The results revealed that the Microcystis spp. bloom sample contained microcystins of which 21 putatively congeners were detected. Among these, 12 known microcystins (MC-RR, MC-LR, MC-FR, MC-WR, MC-YR, MC-LA, MC-(H4)YR, MC-HilR, [Asp(3)]MC-RAba, and [Glu(OCH3)(6)]MC-LR) and two new congeners ([Asp(3)]MC-HarAba and [Glu(OCH3)(6)]MC-FR) were characterized, considering their molecular mass and the fragment ions produced by collision-induced dissociation of the [M+H](+) ions. MC-RR was the major (43.4%) in the bloom sample.
authors.affiliation: Laboratoire Biodiversité et Pollution des Écosystèmes, Faculté des Sciences de la Nature et de la Vie, Université Chadli Bendjedid d'El Taref, Algeria.
authors.forename: Ratiba
authors.initials: R
authors.lastname: Bouhaddada
authors.affiliation: UMR 1402 ECOSYS, INRA, AgroParisTech, Université Paris-Saclay, 78850, Thiverval-Grignon, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Nélieu
authors.affiliation: Laboratoire Biodiversité et Pollution des Écosystèmes, Faculté des Sciences de la Nature et de la Vie, Université Chadli Bendjedid d'El Taref, Algeria.
authors.forename: Hichem
authors.initials: H
authors.lastname: Nasri
authors.affiliation: UMR 1402 ECOSYS, INRA, AgroParisTech, Université Paris-Saclay, 78850, Thiverval-Grignon, France.
authors.forename: Ghislaine
authors.initials: G
authors.lastname: Delarue
authors.affiliation: Écologie, Systématique et Évolution, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91405, Orsay, France. Electronic address: noureddine.bouaicha@u-psud.fr.
authors.forename: Noureddine
authors.initials: N
authors.lastname: Bouaïcha
mesh_terms: D000462:Algeria; D000818:Animals; D001681:Biological Assay; D002853:Chromatography, Liquid; D004784:Environmental Monitoring / Q000379:methods; D005068:Eutrophication; D060106:Lakes / Q000737:chemistry / Q000382:microbiology*; D013058:Mass Spectrometry; D052998:Microcystins / Q000032:analysis* / Q000378:metabolism; D046931:Microcystis / Q000378:metabolism* / Q000502:physiology
chemical_list: D052998:Microcystins
keywords: Cyanobacteria; Cyanotoxins; Mass spectrometry; Microcystin variants; PP2A inhibition test