Improved Isolation Procedures for Okadaic Acid Group Toxins from Shellfish (Mytilus edulis) and Microalgae (Prorocentrum lima).

Jane Kilcoyne,Elliott J Wright,Stephen Burrell,Cíara Nulty,Isabelle Rajotte,Christopher O Miles,Rafael Salas

doi:10.3390/md18120647

Jane Kilcoyne, Elliott J Wright + Show 5 more

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https://doi.org/10.3390/md18120647

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Journal: Marine Drugs	Publication Date: Dec 16, 2020
Citations: 9	License type: CC BY 4.0

Affiliation: Marine Institute, National Research Council Canada

Abstract

Okadaic acid (OA) group toxins may accumulate in shellfish and can result in diarrhetic shellfish poisoning when consumed by humans, and are therefore regulated. Purified toxins are required for the production of certified reference materials used to accurately quantitate toxin levels in shellfish and water samples, and for other research purposes. An improved procedure was developed for the isolation of dinophysistoxin 2 (DTX2) from shellfish (M. edulis), reducing the number of purification steps from eight to five, thereby increasing recoveries to ~68%, compared to ~40% in a previously reported method, and a purity of >95%. Cell densities and toxin production were monitored in cultures of Prorocentrum lima, that produced OA, DTX1, and their esters, over ~1.5 years with maximum cell densities of ~70,000 cells mL−1 observed. Toxin accumulation progressively increased over the study period, to ~0.7 and 2.1 mg L−1 of OA and DTX1 (including their esters), respectively, providing information on appropriate harvesting times. A procedure for the purification of OA and DTX1 from the harvested biomass was developed employing four purification steps, with recoveries of ~76% and purities of >95% being achieved. Purities were confirmed by LC-HRMS, LC-UV, and NMR spectroscopy. Additional stability observations led to a better understanding of the chemistry of these toxins.

Highlights

Okadaic acid (OA) group toxins (Figure 1) are lipophilic polyether toxins produced by the genera Prorocentrum [1,2] and Dinophysis [3,4] that can lead to diarrhetic shellfish poisoning (DSP)events
OA, dinophysistoxin 1 (DTX1), and PTX2 were isolated via large-scale cultivation of D. acuminata [24]
Sources of dinophysistoxin 2 (DTX2) for purification have come from shellfish (Mytilus edulis) [25,26,27], and in situ harvesting of a D. acuta bloom [28]

Summary

Introduction

Okadaic acid (OA) group toxins (Figure 1) are lipophilic polyether toxins produced by the genera Prorocentrum [1,2] and Dinophysis [3,4] that can lead to diarrhetic shellfish poisoning (DSP)events. Okadaic acid (OA) group toxins (Figure 1) are lipophilic polyether toxins produced by the genera Prorocentrum [1,2] and Dinophysis [3,4] that can lead to diarrhetic shellfish poisoning (DSP). The OA group is comprised principally of okadaic acid (OA), dinophysistoxin 1 (DTX1), dinophysistoxin 2 (DTX2), and their esters [4]. The esters can be produced by the microalgae (Dinophysis and Prorocentrum spp.) [6,7,8,9], or by the shellfish via esterification of the toxins [10]. Sources of DTX2 for purification have come from shellfish (Mytilus edulis) [25,26,27], and in situ harvesting of a D. acuta bloom [28].

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