Dynamics of paralytic shellfish toxins and their metabolites during timecourse exposure of scallops Chlamys farreri and mussels Mytilus galloprovincialis to Alexandrium pacificum

Paralytic shellfish toxin profiles in mussel, cockle and razor shell under post-bloom natural conditions: Evidence of higher biotransformation in razor shells and cockles

“…and dcSTX, respectively, may occur in the presence of a carbamoylase enzyme, through the hydrolysis of the benzoate group . In addition, the conversion of C1+2 and C3+4 into M1 and M7 toxins, respectively, by desulfation of the 11-hydroxysulfate group and the conversion of GTX5 into M1, by hydroxylation of the same group, should also be considered (Qiu et al, 2018;Ding et al, 2017;Li et al, 2012;Vale, 2010).…”

“…The most studied analogues are divided into three families, according to their side chains: carbamoil (saxitoxin-STX, neosaxitoxin-NEO and gonyautoxins-GTX1 to GTX4), N-sulfocarbamoil (GTX5, GTX6 and C1 to C4) and decarbamoil (dcGTX1 to dcGTX4, dcSTX and dcNEO) (Oshima, 1995a). Other families have been identified, such as deoxydecarbamoil (doSTX, doGTX2 and doGTX3), hydroxy-and sulfate-benzoate toxins (GC toxins), and hydroxylated saxitoxins (M toxins), whose origin and biosynthesis pathway is not yet fully understood (Qiu et al, 2018;Ding et al, 2017;Li et al, 2012;Vale, 2010;Wiese et al, 2010;Dell'Aversano et al, 2008;Negri et al, 2007Negri et al, , 2003. Bivalves as filter feeding organisms may accumulate and biotransform those compounds in their tissues during toxic algal blooms (Bricelj and Shumway, 1998).…”

“…Biotransformation of toxins in bivalves may occur as a result of epimerization, oxidation, reduction, desulfation and hydrolysis reactions, enzymatic action, and also as a consequence of transformation by bacteria present in their digestive tract (Qiu et al, 2018;Ding et al, 2017;Turner et al, 2013;Donovan et al, 2009;Artigas et al, 2007;Fast et al, 2006;Smith et al, 2001;Murakami et al, 1999;Oshima, 1995b;Kotaki et al, 1985;Shimizu and Yoshioka, 1981). Biotransformation processes play an important role on the toxin excretion, leading to possible differences in toxicity and depuration kinetics among bivalve species (Bricelj and Shumway, 1998).…”

Semiquantitation of Paralytic Shellfish Toxins by Hydrophilic Interaction Liquid Chromatography-Mass Spectrometry Using Relative Molar Response Factors

“…More recently, some new C-11 hydroxyl analogs of PSTs have been reported in shellfish such as scallops, mussels, cockles and clams [3][4][5][6][7]. These new analogs are generally considered to be metabolites of PSTs in shellfish and are called "M-toxins" (Figure 1) [3,[6][7][8]. Recently, trace amounts of several M-toxins were also reported in the PST-producing dinoflagellates Alexandrium spp.…”

“…Recently, trace amounts of several M-toxins were also reported in the PST-producing dinoflagellates Alexandrium spp. [8,9] and cyanobacteria of the genus Aphanizomenon [10]. They have also been formed through chemical degradation, [7] adding further uncertainty and complexity to their origin and formation.…”