From the sxtA4 Gene to Saxitoxin Production: What Controls the Variability Among Alexandrium minutum and Alexandrium pacificum Strains?

Paralytic shellfish poisoning (PSP) is a human foodborne syndrome caused by the consumption of that accumulate paralytic toxins (PSTs, saxitoxin group). In PST-producing dinoflagellates such as Alexandrium spp., toxin synthesis encoded in nuclear genome via gene cluster ( sxt ). Toxin production supposedly associated with presence 4th domain sxtA sxtA4 ), one core genes PST cluster. It postulated expression partially constitutive, both transcriptional and post-transcriptional processes potentially co-occurring. Therefore, structure mode are two important features to explore order fully understand dinoflagellates. this study, we determined intracellular contents twenty European minutum pacificum strains compared their size copy numbers. We observed significant correlation between number content, well moderate positive size. The 18 toxic had several copies (9–187), whereas only was found non-toxin producing strains. Exploration allelic frequencies mRNA 11 A. showed differential specific forms non-toxic ones. Also, exhibited polymorphic sequence within Finally, our study supported hypothesis genetic determinism (i.e., existence isoforms numbers), also consistent constitutive moderation regulation mechanisms cause variability .