title: SxtA and sxtG gene expression and toxin production in the Mediterranean Alexandrium minutum (Dinophyceae).
abstract: The dinoflagellate Alexandrium minutum is known for the production of potent neurotoxins affecting the health of human seafood consumers via paralytic shellfish poisoning (PSP). The aim of this study was to investigate the relationship between the toxin content and the expression level of the genes involved in paralytic shellfish toxin (PST) production. The algal cultures were grown both in standard f/2 medium and in phosphorus/nitrogen limitation. In our study, LC-HRMS analyses of PST profile and content in different Mediterranean A. minutum strains confirmed that this species was able to synthesize mainly the saxitoxin analogues Gonyautoxin-1 (GTX1) and Gonyautoxin-4 (GTX4). The average cellular toxin content varied among different strains, and between growth phases, highlighting a decreasing trend from exponential to stationary phase in all culture conditions tested. The absolute quantities of intracellular sxtA1 and sxtG mRNA were not correlated with the amount of intracellular toxins in the analysed A. minutum suggesting that the production of toxins may be regulated by post-transcriptional mechanisms and/or by the concerted actions of alternative genes belonging to the PST biosynthesis gene cluster. Therefore, it is likely that the sxtA1 and sxtG gene expression could not reflect the PST accumulation in the Mediterranean A. minutum populations under the examined standard and nutrient limiting conditions.
authors.affiliation: Department of Biomolecular Sciences, University of Urbino, Viale Trieste 296, Pesaro 61121, Italy. federico.perini@uniurb.it.
authors.forename: Federico
authors.initials: F
authors.lastname: Perini
authors.affiliation: Department of Biomolecular Sciences, University of Urbino, Viale Trieste 296, Pesaro 61121, Italy. luca.galluzzi@uniurb.it.
authors.forename: Luca
authors.initials: L
authors.lastname: Galluzzi
authors.affiliation: Department of Pharmacy, University of Naples Federico II, Via D. Montesano 49, Naples 80131, Italy. dellaver@unina.it.
authors.forename: Carmela
authors.initials: C
authors.lastname: Dell'Aversano
authors.affiliation: Department of Pharmacy, University of Naples Federico II, Via D. Montesano 49, Naples 80131, Italy. emma.delloiacovo@unina.it.
authors.forename: Emma Dello
authors.initials: ED
authors.lastname: Iacovo
authors.affiliation: Department of Pharmacy, University of Naples Federico II, Via D. Montesano 49, Naples 80131, Italy. luciana.tartaglione@unina.it.
authors.forename: Luciana
authors.initials: L
authors.lastname: Tartaglione
authors.affiliation: Department of Biomolecular Sciences, University of Urbino, Viale Trieste 296, Pesaro 61121, Italy. fabio.ricci@uniurb.it.
authors.forename: Fabio
authors.initials: F
authors.lastname: Ricci
authors.affiliation: Department of Pharmacy, University of Naples Federico II, Via D. Montesano 49, Naples 80131, Italy. forino@unina.it.
authors.forename: Martino
authors.initials: M
authors.lastname: Forino
authors.affiliation: Department of Pharmacy, University of Naples Federico II, Via D. Montesano 49, Naples 80131, Italy. ciminiel@unina.it.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Ciminiello
authors.affiliation: Department of Biomolecular Sciences, University of Urbino, Viale Trieste 296, Pesaro 61121, Italy. antonella.penna@uniurb.it.
authors.forename: Antonella
authors.initials: A
authors.lastname: Penna
mesh_terms: D004141:Dinoflagellida / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression / Q000235:genetics*; D005810:Multigene Family / Q000235:genetics; D009498:Neurotoxins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D012530:Saxitoxin / Q000031:analogs & derivatives* / Q000235:genetics* / Q000378:metabolism; D057096:Shellfish Poisoning / Q000235:genetics / Q000378:metabolism
chemical_list: D009498:Neurotoxins; D012333:RNA, Messenger; D012530:Saxitoxin; C042154:gonyautoxin I