In vitro transformation of paralytic shellfish toxins in the clams Mya arenaria and Protothaca staminea |
| |
Authors: | Mark D. Fast Allan D. Cembella Neil W. Ross |
| |
Affiliation: | aDepartment of Biology, Dalhousie University, Halifax, NS, Canada B3H 4R2;bInstitute for Marine Biosciences, National Research Council, 1411 Oxford Street, Halifax, NS, Canada B3H 3Z1 |
| |
Abstract: | Dissected tissues of two clam species, the Pacific littleneck, Protothaca staminea, and soft-shell, Mya arenaria, were evaluated for in vitro conversion of paralytic shellfish poisoning (PSP) toxins. Tissue homogenates were incubated with purified PSP toxins to determine the time-course of toxin conversion. The effects of boiling and addition of a natural reductant (glutathione) on toxin conversion were also assessed. For P. staminea, the digestive gland showed the greatest capacity for biotransformation, followed by gill, but mantle, adductor muscle, and siphon tissues exhibited very low conversion. In this species, the production of decarbamoyl derivatives was much greater from low potency N-sulfocarbamoyl toxins than from carbamate analogues. Decarbamolyation exhibited apparent specificity for α-epimers of all toxin substrates and this reaction was inhibited by boiling. Glutathione-mediated desulfation was tissue specific and had apparent specificity for β-epimers. These observations on P. staminea suggest that the above reactions are enzyme-mediated. In contrast, there was little toxin conversion in M. arenaria homogenates, but even this low activity was heat-labile and thus likely enzyme-mediated. |
| |
Keywords: | Carbamoylase Clams Mya arenaria Paralytic shellfish toxins Protothaca staminea |
本文献已被 ScienceDirect 等数据库收录! |
|