Accumulation, Biotransformation, Histopathology and Paralysis in the Pacific Calico Scallop Argopecten ventricosus by the Paralyzing Toxins of the Dinoflagellate Gymnodinium catenatum

Abstract

The dinoflagellate Gymnodinium catenatum produces paralyzing shellfish poisons that are consumed and accumulated by bivalves. We performed short-term feeding experiments to examine ingestion, accumulation, biotransformation, histopathology, and paralysis in the juvenile Pacific calico scallop Argopecten ventricosus that consume this dinoflagellate. Depletion of algal cells was measured in closed systems. Histopathological preparations were microscopically analyzed. Paralysis was observed and the time of recovery recorded. Accumulation and possible biotransformation of toxins were measured by HPLC analysis. Feeding activity in treated scallops showed that scallops produced pseudofeces, ingestion rates decreased at 8 h; approximately 60% of the scallops were paralyzed and melanin production and hemocyte aggregation were observed in several tissues at 15 h. HPLC analysis showed that the only toxins present in the dinoflagellates and scallops were the N-sulfo-carbamoyl toxins (C1, C2); after hydrolysis, the carbamate toxins (epimers GTX2/3) were present. C1 and C2 toxins were most common in the mantle, followed by the digestive gland and stomach-complex, adductor muscle, kidney and rectum group, and finally, gills. Toxin profiles in scallop tissue were similar to the dinoflagellate; biotransformations were not present in the scallops in this short-term feeding experiment.

Effects of bioactive extracellular compounds and paralytic shellfish toxins produced by Alexandrium minutum on growth and behaviour of juvenile great scallops Pecten maximus

“…So, an increase in clapping time, as observed here, might result from the response of the smooth adductor muscle to bioactive compounds, as suggested by the haemocyte infiltrations into the muscle of BEC-exposed scallops. Such haemocyte infiltrations in the adductor muscle have previously been observed in A. ventricosus exposed to Gymnodinium catenatum (Escobedo-Lozano et al 2012), and this has been interpreted as a defence mechanism to evacuate bioactive extracellular compounds and limit the alteration of the muscle.…”

“…Bricelj et al (2005) showed that burrowing of Mya arenaria was not affected by exposure to non-PST-producing A. tamarense strain (CCMP115), but that incapacity to burrow was toxin-induced in clams and resulted from muscle paralysis (Bricelj et al, 1990;. The link between the accumulation of PSTs and the paralysis of the adductor muscle has been observed in several bivalve species, such as C. gigas, M. edulis or A. ventricosus exposed to PST-producing dinoflagellates (Hégaret et al, 2007;Galimany et al, 2008;Escobedo-Lozano et al, 2012). Moreover, the injection of gonyautoxin (GTX, a saxitoxinlike toxin), produced by G. catenatum, into the muscle of the scallop N. subnodosus induced paralysis (Estrada et al, 2010).…”

Apoptosis of hemocytes from lions-paw scallop Nodipecten subnodosus induced with paralyzing shellfish poison from Gymnodinium catenatum

“…Examination under an optical microscope of the cell debris, after homogenization, showed that the cells were completely disrupted. The starting material was a largescale laboratory culture of G. catenatum, and its principal toxin was N-sulfo-carbamoyl (C1, C2), as previously described (Estrada et al, 2007;Escobedo-Lozano et al, 2012). As described by Laycock et al (1994), these N-sulfo-carbamoyl toxins were extracted and chemically converted to their analog carbamates, a mixture of GTX 2/3 (∼3:1).…”

Tissue-Biased and Species-Specific Regulation of Glutathione Peroxidase (GPx) Genes in Scallops Exposed to Toxic Dinoflagellates

“…catenella (ACDH strain) [ 38 , 48 ]. Briefly, 2-year-old adult scallops were collected and acclimated in filtered and aerated seawater at 12–13 °C for three weeks for depuration by feeding the non-toxic algae, Isochrysis galbana (7.5 × 10 5 cells/mL) as the control group [ 59 ]. 18 scallops were separated into independent tanks with aeration, and 6 groups with 3 individuals for each were taken at different test time points (0, 1, 3, 5, 10, and 15 days) during the challenging experiments.…”