Enzymatic transformation of PSP toxins in the littleneck clam (Protothacastaminea)

Sullivan, John J.; Iwaoka, Wayne T.; Liston, J.

doi:10.1016/0006-291x(83)90803-3

Cited by 130 publications

(58 citation statements)

References 12 publications

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“…In contrast, it was reported that the toxin profiles of the Tasmanian dinoflagellate Gymnodinium catenatum and infested shellfish were characterized by unusually high proportions of low-potency sulfocarbamoyl toxin, which comprised 98ῌ99῎ and 77ῌ93῎, respectively, of total toxins 20) . Shimizu et al suggested the presence of enzymatic processes involving the transformation of GTXs to STX through the reductive elimination of the 22) . Thus, these transformations of PSP components in bivalves can reasonably account for the large di#erences of toxin composition between the dinoflagellate and the filter feeders 23) .…”

Section: Resultsmentioning

confidence: 99%

Occurrence of Paralytic Shellfish Poison (PSP)-Producing Dinoflagellate Alexandrium tamarense in Hiroshima Bay, Hiroshima Prefecture, Japan, during 1993-2004 and Its PSP Profiles

Asakawa

Takayama²,

Beppu³

et al. 2005

J. Food Hyg. Soc. Jpn

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To assess levels of shellfish intoxication by the paralytic shellfish poison (PSP)-producing dinoflagellate Alexandrium tamarense, potential health risks to human shellfish consumers and the possible need for regulatory intervention, yearly variations of maximum cell density of this species were examined from 1993 to 2004 in Kure Bay and Kaita Bay, which are located within Hiroshima Bay, Hiroshima Prefecture, Japan. The seawater temperature was determined concomitantly. In Kure Bay, maximum concentrations of 1,400 and 1,300 cells/mL at 0 and 5 m depths were observed on 21 and 24 April 1997. In Kaita Bay, remarkably high concentrations above 1,000 cells/mL of A. tamarense were observed in two out of three years investigated. These facts suggest that the environment in both bays is favorable for the propagation of A. tamarense. The temperature range at which the natural population of A. tamarense blooms was generally from 12 to 16῎. Four strains (ATKR-94, -95, -97 and -01) from Kure Bay and one strain (ATKT-97) from Kaita Bay were established. The strain ATKR-94, cultured in modified SW-2 medium at 15῎ for 15 days, showed a specific toxicity of 33.8῍10ῌ6 MU/cell. The toxins in all five strains exist almost exclusively as b-epimers (C2 (PX2 or GTX8), GTX3, dcGTX3 and GTX4), which accounted for 54.9 to 73.0 mol῏ of the total. The corresponding a-epimers (C1 (PX1 or epi-GTX8), GTX2, dcGTX2 and GTX1) accounted for 6.0 to 28.9 mol῏. The toxin profiles of ATKR-97 and ATKT-97 were characterized by unusually high proportions of low-potency sulfocarbamoyl toxin, which comprised 62.4 and 68.2 mol῏, respectively, of total toxins. In the toxic bivalves, the low-toxicity sulfocarbamoyl components, major components of A. tamarense, were present in amounts of only a few percent, suggesting that in vivo conversion of PSP occurs after ingestion.A comparison of the toxin profiles of the causative dinoflagellate and contaminated bivalves showed that PSP components exist in the bivalves in the form of a-epimers, presumably owing to accumulation or storage of the toxins.

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Section: Resultsmentioning

confidence: 99%

Occurrence of Paralytic Shellfish Poison (PSP)-Producing Dinoflagellate Alexandrium tamarense in Hiroshima Bay, Hiroshima Prefecture, Japan, during 1993-2004 and Its PSP Profiles

Asakawa

Takayama²,

Beppu³

et al. 2005

J. Food Hyg. Soc. Jpn

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“…However, little is known about the metabolism of the toxins in the bivalves, though transformation of toxin components has been reported (Shimizu & Yoshioka 1981, Sullivan et al 1983, Oshima et al 1990, Oshima 1995a. The results of the present study indicate that the metabolism of PSP toxins in the bivalves is more complex than the transformation of toxin components.…”

Section: Accumulation and Release Of Psp Toxins By The Scallopmentioning

confidence: 99%

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

Sekiguchi¹,

Satō²,

Ogata³

et al. 2001

Mar. Ecol. Prog. Ser.

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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...

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“…It is of note that metabolic processes in at least some accumulating organisms can remove the N-l -hydroxyl and 1 i -hydroxysulfate groups and the carbmte and sulfamate side chains from the saxitoxins (Proctor et al,, 1975;Shimizu and Yoshioka, 198 1;Sullivan et al, 1983). The demonstration of toxin conversion within shellfish tissue (Shimizu and Yoshioka, 1981) is relevant to the whale poisonings in that the only toxin detected by HPLC in mackerel liver during the mortality event was saxitoxin, despite the presence of many other saxitoxin derivatives in Alexandrium cells from that region (see section I1 A).…”

Section: Toxin Assaysmentioning

confidence: 99%

“…Decarbamoylation of the toxins by shellfish (Sullivan et al, 1983) is noteworthy in light of the lack of saxitoxin peaks in HPLC analyses of whale tissues, despite the strong signs of saxitoxin-like poisoning in mice injected with those extracts and the positive results from tissue culture assay. Decarbamoylation reduces toxin potency only slightly, but does make the cornponds difficult to detect by the HPLC technique now in common use.…”

Section: Toxin Assaysmentioning

confidence: 99%

Toxic dinoflagellates and marine mammal mortalities : proceedings of an expert consultation held at the Woods Hole Oceanographic Institution

Anderson¹,

White²

1989

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Enzymatic transformation of PSP toxins in the littleneck clam (Protothacastaminea)

Cited by 130 publications

References 12 publications

Occurrence of Paralytic Shellfish Poison (PSP)-Producing Dinoflagellate Alexandrium tamarense in Hiroshima Bay, Hiroshima Prefecture, Japan, during 1993-2004 and Its PSP Profiles

Occurrence of Paralytic Shellfish Poison (PSP)-Producing Dinoflagellate Alexandrium tamarense in Hiroshima Bay, Hiroshima Prefecture, Japan, during 1993-2004 and Its PSP Profiles

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

Toxic dinoflagellates and marine mammal mortalities : proceedings of an expert consultation held at the Woods Hole Oceanographic Institution

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