Efficient isolation of the rare diarrhoeic shellfish toxin, dinophysistoxin-2, from marine phytoplankton.

Abstract

The rare diarrhoeic shellfish poisoning (DSP) toxin, dinophysistoxin-2 (DTX-2), which is an okadaic acid (OA) isomer, has been isolated from a marine phytoplankton biomass that consisted mainly of Dinophysis acuta. Using a large double plankton net (length 5.9 m), bulk phytoplankton samples were collected off the south-west coast of Ireland and extracted with methanol and chloroform. Liquid chromatography coupled with ionspray mass spectrometry and tandem mass spectrometry (LC-MS, LC-MS-MS) showed the sample contained DTX-2 and OA, at a concentration of 80 pg/cell and 60 pg/cell, respectively. Flash chromatography using silica, sephadex LH20 and C18-silica, followed by preparative reversed-phase LC, separated DTX-2 from OA. The efficiency of the separation procedures was substantially improved by the use of a bioscreen to detect DSP toxins in eluate fractions and the application of a new derivatisation procedure for the chromatographic elucidation of toxin profiles with fluorimetric detection (LC-FLD). Thus, 1/1000th aliquots of eluate fractions were assayed using protein phosphatase-2A for the presence of inhibitory compounds. Positive fractions were further analysed for DSP toxins by LC-FLD following derivatisation using the hydrazine reagent, luminarine-3. The identity and purity of the free isolated DTX-2 was confirmed using flow injection analysis (FIA) and liquid chromatography (FIA-MS, LC-MS and LC-MS-MS).

• Authors: K J James, A G Bishop, B M Healy, C Roden, I R Sherlock, M Twohig, R Draisci, L Giannetti, L Lucentini
• Journal: Toxicon : official journal of the International Society on Toxinology (Toxicon) Vol. 37 Issue 2 Pg. 343-57 (Feb 1999) ISSN: 0041-0101 [Print] England
• PMID: 10078864 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Hydrazines
• Marine Toxins
• Pyrans
• Okadaic Acid
• hydrazine
• Phosphoprotein Phosphatases
• Protein Phosphatase 2
• dinophysistoxin 2

Topics

• Animals
• Diarrhea (chemically induced)
• Fluorometry
• Gas Chromatography-Mass Spectrometry
• Hydrazines (chemistry)
• Marine Toxins (analysis, isolation & purification)
• Okadaic Acid (analogs & derivatives, analysis)
• Phosphoprotein Phosphatases (chemistry)
• Phytoplankton (chemistry)
• Protein Phosphatase 2
• Pyrans (analysis, isolation & purification)
• Shellfish
• Stereoisomerism