ABSTRACT
Marine toxins are a very large and complex group of compounds from different origins. They are produced by actinomycetes, cyanobacteria (Leao et al., 2012), sponges (Bondu et al., 2012), bacteria, gasteropods (Wang et al., 2006), and so on (Nikapitiya, 2012). Their biological role is intended for defense or predation, but in some cases, their role is unknown or ts in the undened role of secondary metabolites (Kita et al., 2010, Nikapitiya, 2012, Proksch, 1994). The toxins covered in this chapter, the phycotoxins (produced by algae), affect a specic problem related to food safety, and pose an analytical challenge for health authorities. Phycotoxins are produced by unicellular microalgae, mostly photoautotrophic, heterotrophic, or mixotrophic dinoagellates (Reguera and Pizarro, 2008) and a few diatoms (Vasconcelos et al., 2010). They are distributed worldwide, and from their ecological environment, they show different patterns of toxin production (Kellmann et al., 2010, Lin, 2011, Litaker et al., 2010, Otero et al., 2010a). Given the extreme diversity of the genes responsible of the production of the toxin skeletons, and the molecular enzymatic machinery for the biosynthesis of the toxins, the polyketide synthases (Fujii, 2009, Monroe and Van Dolah, 2008), the number of marine phycotoxins is very high (several hundreds), although they are classied in few chemical groups (see Table 6.1). These toxins are very relevant to food and health authorities because they accumulate in very high amounts in lter feeding mollusks and gasteropods, to levels that may even allow a couple of mussels to reach lethal quantities, or one single conch to be potentially lethal. Even though most of the toxins are not lethal, those few groups that can cause death to humans are especially dangerous. The monitoring and surveillance systems in all producing countries are costly and require international standardization, since shellsh are very important in international trading (Vieites and Cabado, 2008). In addition to the cost of monitoring the presence of toxins in seafood, they are an economical problem for producers, and their presence closes production areas for long periods of time, causing major losses.
