pectenotoxin-2 and Diarrhea

Toxins produced by harmful algae are associated with detrimental health effects and mass mortalities of marine mammals. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is generally used to confirm the presence of algal toxins in marine mammals. Sample preparation and LC-MS/MS methods for the determination of three diarrhetic shellfish poisoning (DSP) toxins (okadaic acid, OA; dinophysistoxin-1, DTX1; dinophysistoxin-2, DTX2) and pectenotoxin-2 (PTX2) in bottlenose dolphin (Tursiops truncatus) urine and tissue samples were evaluated using spike-and-recovery tests. Sample clean-up with either reversed-phase silica or polymeric solid-phase extraction (SPE) reduced interference of sample matrices and improved toxin recoveries, with polymeric SPE showing higher sample loading capacity. LC separation on Xbridge C18 columns using acetonitrile/water gradient elutions with ammonia as the additive was chosen for its high detectivity and sensitivity in the MS detection of DSP toxins in negative ion mode. The retention times of OA, DTX1, and DTX2, separated as negative ions, increased with LC column temperature while the retention time of PTX2, separated as the neutral molecule, was weakly affected. At the same column temperature, retention times of OA, DTX1, and DTX2 gradually increased as the mobile phases aged while the retention time of PTX2 remained unchanged; higher column temperatures resulted in a greater increase in the retention time of each DSP toxin with mobile phase aging. Average recoveries of the 4 toxins in bottlenose dolphin samples ranged from 80% to 130% with relative standard deviations of less than 15% using the LC mobile phases prepared within one week at a column temperature of 30°C or 40°C. The preferred column temperature was 30°C, as the retention times of DSP toxins were less affected by mobile phase aging at this temperature. The limit of detection of each toxin analyzed in bottlenose dolphin samples was 2.8 ng/g or less in tissue samples and 0.7 ng/ml or less in urine.

Topics: Animals; Bottle-Nosed Dolphin; Chromatography, Liquid; Diarrhea; Furans; Macrolides; Marine Toxins; Okadaic Acid; Pyrans; Shellfish Poisoning; Solid Phase Extraction; Tandem Mass Spectrometry

Diarrhetic activity of pectenotoxin-6 (PTX6), a shellfish contaminant in Japanese scallops (Patinopecten yessoensis), was studied in vivo. Mice gavaged with 5mg/kg PTX6 did not show diarrhea or fluid secretion, and no prominent pathological changes were observed. There was no synergistic toxicity of PTX6 with okadaic acid (OA) or pectenotoxin-2 (PTX2) when toxins were given to mice by gavage. Synergistic activity of PTX6 with OA was also not confirmed under crude conditional simulation with oil. In contrast to the oral administration to mice, PTX6 at 500 microg/kg by i.p. was the lethal dose with bleeding in the liver, injuries at the gastric organs and the kidney. When rats were gavaged with PTX6 at a dose of 2 mg/kg, PTX6 did not have diarrhetic activity; however, the middle-lower small intestine (jejunum-ileum) was eroded at villi by edema. PTX6 is a potent toxin if administered by intraperitoneal injection to mice, or if administered orally to the rat. However, it is not clear if PTX6 passes through the intestinal barrier if given by the oral route.

Topics: Animals; Diarrhea; Dose-Response Relationship, Drug; Furans; Intestine, Small; Macrolides; Male; Marine Toxins; Mice; Mice, Inbred ICR; Molecular Structure; Okadaic Acid; Pectinidae; Pyrans; Rats; Rats, Wistar; Time Factors