Accumulation and depuration kinetics of paralytic shellfish toxins in the scallop Patinopecten yessoensis fed Alexandrium tamarense

Abstract

Adult scallops, Patinopecten yessoensis, held for 8 d separately in tanks and fed known amounts of cultured cells of the dinoflagellate Alexandrium tamarense were held without feeding for an additional 10 d. During the 18 d study, 3 scallops were removed every 2 d and the quantity of of each toxin present was analyzed individually. The toxins released into the environmental seawater were recovered and also analyzed. These experiments showed that the individual variation in bivalve toxicity often observed in feeding experiments and field surveys is due to differences in the amounts of dinoflagellate cells ingested by the bivalves and that a portion of the total amount of toxins accumulated in the scallop is released into the environmental water. However, the sum of the amount of toxins in the scallop and that released into the water cannot be explained in terms of the amount supplied by A. tamarense, suggesting that in addition to toxin accumulation from the food chain, another unknown mechanism is involved in toxin accumulation in the scallop. The toxins incorporated into the scallop from A. tamarense are considered to undergo metabolism in the scallop through which the toxins are changed to derivatives undetectable by HPLC. KEY WORDS: Scallop · Patinopecten yessoensis · Alexandrium tamarense · Feeding experiment · Paralytic shellfish toxins Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 220: [213][214][215][216][217][218] 2001 Alexandrium tamarense, a dinoflagellate known to be a causative agent of PSP (Ogata et al. 1982, Sekiguchi et al. 1989. In the survey, we observed some phenomena that could not be explained on the basis of the food chain mechanism of toxin accumulation in bivalves; that is, the scallop toxicity did not increase in parallel with the abundance of A. tamarense. We found that scallop toxicity is low when A. tamarense shows maximal abundance, but was highest when the cell density of A. tamarense decreased from the maximal peak. Furthermore, scallop toxicity often increased after the disappearance of A. tamarense. However, it was impossible to examine the amounts of toxins supplied by dinoflagellates and the amounts excreted from the scallop quantitatively in the field survey. Therefore, the phenomena observed in the field survey, which could not be explained in terms of the currently accepted mechanism, could not be elucidated by field data. Although it is important to understand the mechanism by which bivalves become toxic through ingestion of toxic dinoflagellates in order to establish effective countermeasures for PSP problems, there have been few studies on this mechanism.Previously, we reported that bivalve specimens reared in the same tank and fed cultured Alexandrium tamarense showed marked individual variation in the levels of accumulated toxins, probably because of differences in the extent of ingestion of A. tamarense (Sekiguchi et al. 2001). These findings suggest that the phenomena with respect to scallop toxicity in the...

Prediction of on-site depuration of paralytic shellfish poisoning toxins accumulated in the scallop Patinopecten yessoensis of Ofunato Bay, Japan

“…For example, during a no-feeding period in a feeding experiment, some of the toxin supplied (the sum of the amount of toxins in the scallop and that released into the environmental water) seemed to disappear, and most of the supplied toxin was recovered thereafter [17]. This result indicates that decomposition of toxins in the scallop is unlikely, and suggests that the decrease in accumulated toxins is due to excretion of the toxins into the ambient seawater.…”

Biochemical features of a <i>Protoceratium reticulatum</i> red tide in Chipana Bay (Northern Chile) in summer conditions

“…The effectiveness of these molecules depends on the environmental conditions in which P. reticulatum grows (Guerrini et al, 2007). Because the effect of toxins depends on the time of organism exposure to the red tide (Sekiguchi et al, 2001), a deeper knowledge of red tide dynamics is a main target to plan Harmful Algae Bloom (HAB) monitoring programmes. However, dinoflagellates are known to have high caloric value (Hithcock, 1982), and a red tide could be attractive for some suspension feeders, despite its potential toxicity (Fernández-Reiriz et al, 2008).…”

“…Moderate-to-low concentrations of some dinoflagellates (e.g. Alexandrium catenella, Dinophysis acuta, Protoceratium reticulatum) are responsible for the accumulation of toxins that may be associated not only with the negative effects on fisheries (Sekiguchi et al, 2001), but on the physiology and production of shellfish (Li et al, 2002). In particular, the dinoflagellate Protoceratium reticulatum contains high levels of yessotoxins (Satake et al, 1997;Paz et al, 2007), which may be highly toxic and have a long-term effect on shellfish populations (Fernández-Reiriz et al, 2008).…”

Toxin profile change in vegetative cells and pellicle cysts of Alexandrium fundyense after gut passage in the eastern oyster Crassostrea virginica

“…In most studies, the PST content of the medium was not measured. In a few studies with bivalves, a column with activated charcoal was used to adsorb dissolved PSTs for sub sequent elution and analysis (Sekiguchi et al 2001, Suzuki et al 2003, Asakawa et al 2006. A recent study by Lefebvre et al (2008) using a receptor-binding assay (RBA) and an enzyme-linked immunosorbent assay (ELISA) found extracellular PSTs in both field samples and laboratory cultures.…”

“…It is possible to use activated charcoal columns to collect the toxins, as has been done in some studies with bivalves (Sekiguchi et al 2001, Suzuki et al 2003, Asakawa et al 2006. Lefebvre et al (2008) measured the extracellular toxin levels in both field samples and laboratory cultures by receptor binding assay (RBA) and enzyme-linked immunosorbent assay (ELISA).…”