Abstract
In recent years, detection of trace amounts of dissolved lipophilic phycotoxins in coastal waters has been possible using solid phase adsorption toxin tracking (SPATT) samplers. To explore the contribution of dissolved diarrhetic shellfish toxins (DST) to the accumulation of toxins by cultivated bivalves, mussels (Mytilus galloprovincialis) were exposed to different concentrations of purified okadaic acid (OA) and dinophysistoxin-1 (DTX1) in filtered (0.45 µm) seawater for 96 h. Accumulation and esterification of DST by mussels under different experimental conditions, including with and without the addition of the food microalga Isochrysis galbana, and with the addition of different size-fractions of suspended particulate matter (SPM) (<75 µm, 75–150 µm, 150–250 µm) were compared. Results showed that mussels accumulated similar amounts of OA and DTX1 from seawater with or without food microalgae present, and slightly lower amounts when SPM particles were added. Mussels preferentially accumulated OA over DTX1 in all treatments. The efficiency of the mussel’s accumulation of OA and DTX1 from seawater spiked with low concentrations of toxins was higher than that in seawater with high toxin levels. A large proportion of OA (86–94%) and DTX1 (65–82%) was esterified to DTX3 by mussels in all treatments. The proportion of I. galbana cells cleared by mussels was markedly inhibited by dissolved OA and DTX1 (OA 9.2 µg L−1, DTX1 13.2 µg L−1) in seawater. Distribution of total OA and DTX1 accumulated in the mussel tissues ranked in all treatments as follows: digestive gland > gills > mantle > residual tissues. However, the percentage of total DST in the digestive gland of mussels in filtered seawater (67%) was higher than with the addition of SPM particles (75–150 µm) (51%), whereas the gills showed the opposite trend in filtered seawater with (27%) and without (14.4%) SPM particles. Results presented here will improve our understanding of the mechanisms of DST accumulation by bivalves in marine aquaculture environments.
Highlights
Okadaic acid (OA), dinophysistoxin-1 (DTX1) and -2 (DTX2) (Figure 1) are produced by some benthic dinoflagellates of the genus Prorocentrum, such as P. lima [1], P. concavum [2], P. hoffmannianum [3], P. rhathymum [4] and P. foraminosum [5], and by planktonic dinoflagellates of the genus Dinophysis, including D. acuminata, D. acuta, D. caudata, D. fortii, D. miles, D. norvegica, D. ovum, D. sacculus and D. tripos [6]
The free forms of diarrhetic shellfish toxins (DST) (OA, DTX1 and DTX2) produced by microalgae can be esterified in many bivalve species with different fatty acids throughby the
Trace amounts of OA were detected in coastal areas every month, except for elevated levels observed in August [34], indicating that OA
Summary
Okadaic acid (OA), dinophysistoxin-1 (DTX1) and -2 (DTX2) (Figure 1) are produced by some benthic dinoflagellates of the genus Prorocentrum, such as P. lima [1], P. concavum [2], P. hoffmannianum [3], P. rhathymum [4] and P. foraminosum [5], and by planktonic dinoflagellates of the genus Dinophysis, including D. acuminata, D. acuta, D. caudata, D. fortii, D. miles, D. norvegica, D. ovum, D. sacculus and D. tripos [6]. These phycotoxins are called diarrhetic shellfish toxins (DST). DSP has been recognized as one of the five most common illnesses caused by harmful algal bloom toxins, which include ciguatera fish poisoning, paralytic shellfish poisoning, neurotoxic shellfish poisoning and amnesic shellfish [16].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
