Metabolic Transformation of Dinophysistoxin-3 Into Dinophysistoxin-1 Causes Human Intoxication by Consumption of O-Acyl-Derivatives Dinophysistoxins Contaminated Shellfish

Abstract

-This paper describes for the first time a massive intoxication episode due to consumption of shellfish contaminated with 7-O-acyl-derivative dinophysistoxin-1, named Dinophysistoxin-3 (DTX-3). 7-O-acyl-derivative dinophysistoxin-1, a compound recently described in the literature, was found in shellfish samples collected in the Chilean Patagonia fjords. This compound does not inhibit Protein Phosphatases and also does not elicit the symptoms described for Diarrheic Shellfish Poisoning (DSP). The data showed here, give evidence of metabolic transformation of 7-O-acyl-derivative dinophysistoxin-1 (DTX-3) into Dinophysistoxin-1 (DTX-1, Methyl-Okadaic acid) in intoxicated patients. This metabolic transformation is responsible for the diarrheic symptoms and the intoxication syndrome showed by patients that consumed contaminated shellfish, which showed only the presence of 7-O-acyl-derivative dinophysistoxin-1. Patients fecal bacterial analysis for the presence of enteropathogens was negative and the mouse bioassay for DSP, performed as described for regulatory testing, was also negative.The HPLC-FLD and HPLC-MS analysis showed only the presence of DTX-3 as the only compound associated to DSP toxins in the contaminated shellfish samples. No other DSP toxins were found in the shellfish sample extracts. However, the patient fecal samples showed DTX-1 as the only DSP toxins detected in fecal. Moreover, the patient fecal samples did not show DTX-3.Since 7-O-acyl-derivative dinophysistoxin-1 (DTX-3) was the only compound associated to DSP toxins detected in the shellfish samples, an explanation for the diarrheic symptoms in the intoxicated patients would be the metabolic transformation of DTX-3 into DTX-1. This transformation should occur in the stomach of the poisoned patients after consuming 7-O-acyl-derivatives dinophysistoxin-1 (DTX-3) contaminated bivalves.

Development of a monoclonal antibody binding okadaic acid and dinophysistoxins-1, -2 in proportion to their toxicity equivalence factors

“…DSP incidents have been reported worldwide with OA outbreaks more frequently associated with Europe (Kreuzer et al, 1999) while in Japan DTX-1 is more prevalent (Hallegraeff, 1995) and in Ireland, the principal DSP toxin detected is DTX-2 (Carmody et al, 1996). DTX-3 toxic episodes have been reported in Norway, Chile, Portugal and Spain (Vale and Sampayo, 2002;Torgersen et al, 2005;Garcia et al, 2005;VillarGonzalez et al, 2007). Single toxic episodes can be a complex phenomenon involving several distinct groups of natural compounds with the predominant toxin varying in different toxic events.…”

First evidence of Okadaic acid acyl-derivative and Dinophysistoxin-3 in mussel samples collected in Chiloe Island, Southern Chile

“…So, DTX-3 is the most regularly DSP toxins found, being most of the time the only DSP toxin found in shellfish extracts. Some samples also showed DTX-1, but the DTX-3 amount is always prevalent and the highest one in the DSP toxin profile (García et al, 2004(García et al, , 2005(García et al, and 2006 . Therefore, after 4 years of permanently detection of DTX-3 in shellfish samples in many Chilean fjords, the presence of DTX-3 can be considered endemic and also the main DSP toxins in Chilean contaminated shellfish.…”

“…The last two require high concentrations of DSP toxins to be inhibited (Bialojan and Takai, 1988;Rivas et al, 2000). On the other hand, DTX-3 does not inhibit Protein Phosphatase enzymes (Takai et al, 1992), but the DTX-1 ester is straightforwardly hydrolyzed to DTX-1 by digestive enzymes such as lipases and unspecific esterases at the gastric-duodenal level (García et al, 2005). The Phosphatases are highly conserved proteins and OA has been found to interfere with Phosphatase-Kinase-based control mechanism in a broad range of eukaryotic (MacKintosh et al, 1990).The inhibitory effect of DSP toxins on PP2A has been studied in detail (Takai et al, 1992;Sasaki et al, 1994;Rivas et al, 2000).…”

“…In Chile, outbreaks associated to DSP intoxications have occurred throughout Patagonian fjords since 1970 (Lagos, 1998;Muñoz et al, 1992;Uribe et al, 2001;García et al, 2003García et al, , 2004García et al, , 2005García et al, and 2006. Presently, the endemic presence of DSP toxins has been established in the three most austral Regions of Chile (X, XI and XII) (Lagos, 1998;Uribe et al, 2001;García et al, 2004García et al, , 2005García et al, and 2006.…”

“…Presently, the endemic presence of DSP toxins has been established in the three most austral Regions of Chile (X, XI and XII) (Lagos, 1998;Uribe et al, 2001;García et al, 2004García et al, , 2005García et al, and 2006.…”