Marine Toxins in Non-traditional Vectors

A special issue of Marine Drugs (ISSN 1660-3397).

Deadline for manuscript submissions: closed (30 June 2022) | Viewed by 17222

Special Issue Editors

Centre for Environment, Fisheries and Aquaculture Science, Weymouth Laboratory, Lowestoft, UK
Interests: assessment of new marine toxin threats; cyanobacterial toxins; method development; reference materials; rapid testing methods; one health impacts
Special Issues, Collections and Topics in MDPI journals
Cawthron Institute, Nelson, New Zealand
Interests: analysis of marine toxins; analytical method development and validation; natural product isolation; structural elucidation

Special Issue Information

Dear Colleagues,

Marine biotoxins are produced naturally by certain species of algae and bacteria in a wide range of aquatic environments and can accumulate in marine invertebrates. Historically, the primary focus has been upon the presence of toxins in bivalve mollusc shellfish, with regulatory legislation in place for many decades throughout the world to reduce the risks of human poisoning following seafood consumption and to facilitate international trade. More evidence is building, however, for the uptake of marine toxins into non-bivalve molluscs, such as gastropods. Other marine phyla have also been associated with biotoxin presence, including echinoderms, arthropods, cnidarians, bryazoa and annelids, nematodes and flatworms. Furthermore, there are also reports of shellfish toxins being associated with uptake into fish, impacting animal health.

This Special Issue aims to focus on the interactions of non-bivalve marine organisms with harmful blooms of algae or bacteria and the consequent accumulation of biotoxins in their tissues. There is a growing need to focus not only on the presence of toxins in a wide range of pelagic and benthic organisms, but to also assess the impacts these processes may have on human food safety, animal health and ecosystem status (e.g., a One Health perspective).

Manuscript submission is encouraged for new findings of marine biotoxins in non-traditional vectors, including:

(1) detection in non-bivalve invertebrates and fish,
(2) studies describing food safety impacts or risks,
(3) assessment of toxin metabolism and/or toxin transformation in these organisms,
(4) impacts following toxin bioaccumulation on the health of high trophic level animals,
(5) application of new analytical approaches.

This Special Issue is dedicated to the memory of Dr Ann Abraham, USFDA.

Dr. Andrew Turner
Dr. Tim Harwood
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Marine Drugs is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2900 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • marine biotoxins
  • shellfish
  • non-traditional vectors
  • food safety
  • one health
  • market access
  • metabolism and transformation
  • harmful algal blooms

Published Papers (7 papers)

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Research

7 pages, 838 KiB  
Communication
Does Ocean Sunfish Mola spp. (Tetraodontiformes: Molidae) Represent a Risk for Tetrodotoxin Poisoning in the Portuguese Coast?
Mar. Drugs 2022, 20(10), 594; https://doi.org/10.3390/md20100594 - 23 Sep 2022
Cited by 1 | Viewed by 1502
Abstract
Tetrodotoxin (TTX) is a potent neurotoxin naturally occurring in terrestrial and marine organisms such as pufferfish. Due to the risk of TTX poisoning, fish of Tetraodontidae family and other puffer-related species must not be placed in the EU markets. This restriction applies to [...] Read more.
Tetrodotoxin (TTX) is a potent neurotoxin naturally occurring in terrestrial and marine organisms such as pufferfish. Due to the risk of TTX poisoning, fish of Tetraodontidae family and other puffer-related species must not be placed in the EU markets. This restriction applies to fish of the family Molidae even though no data on toxins’ occurrence is available. In this study, the presence of TTX and its analogues was investigated in the main edible tissue (the white muscle) and the main xenobiotics storage organ (the liver) of ocean sunfish Mola spp. (n = 13) from the South Portuguese coast. HILIC-MS/MS analyses did not reveal TTX in the analyzed samples, suggesting an inexistent or very limited risk of TTX poisoning. Full article
(This article belongs to the Special Issue Marine Toxins in Non-traditional Vectors)
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11 pages, 1257 KiB  
Article
Stability of Saxitoxin in 50% Methanol Fecal Extracts and Raw Feces from Bowhead Whales (Balaena mysticetus)
Mar. Drugs 2022, 20(9), 547; https://doi.org/10.3390/md20090547 - 25 Aug 2022
Viewed by 1330
Abstract
In recent decades, harmful algal blooms (HABs) producing paralytic shellfish toxins (including saxitoxin, STX) have become increasingly frequent in the marine waters of Alaska, USA, subjecting Pacific Arctic and subarctic communities and wildlife to increased toxin exposure risks. Research on the risks of [...] Read more.
In recent decades, harmful algal blooms (HABs) producing paralytic shellfish toxins (including saxitoxin, STX) have become increasingly frequent in the marine waters of Alaska, USA, subjecting Pacific Arctic and subarctic communities and wildlife to increased toxin exposure risks. Research on the risks of HAB toxin exposures to marine mammal health commonly relies on the sampling of marine mammal gastrointestinal (GI) contents to quantify HAB toxins, yet no studies have been published testing the stability of STX in marine mammal GI matrices. An understanding of STX stability in test matrices under storage and handling conditions is imperative to the integrity of toxin quantifications and conclusions drawn thereby. Here, STX stability is characterized in field-collected bowhead whale feces (stored raw in several treatments) and in fecal extracts (50% methanol, MeOH) over multiple time points. Toxin stability, as the percent of initial concentration (T0), was reported for each storage treatment and time point. STX was stable (mean 99% T0) in 50% MeOH extracts over the 8-week study period, and there was no significant difference in STX concentrations quantified in split fecal samples extracted in 80% ethanol (EtOH) and 50% MeOH. STX was also relatively stable in raw fecal material stored in the freezer (mean 94% T0) and the refrigerator (mean 93% T0) up to 8 weeks. STX degraded over time in the room-temperature dark, room-temperature light, and warm treatments to means of 48 ± 1.9, 38 ± 2.8, and 20 ± 0.7% T0, respectively, after 8 weeks (mean ± standard error; SE). Additional opportunistically analyzed samples frozen for ≤4.5 years also showed STX to be relatively stable (mean 97% T0). Mean percent of T0 was measured slightly above 100% in some extracts following some treatments, and (most notably) at some long-term frozen time points, likely due to evaporation from samples causing STX to concentrate, or variability between ELISA plates. Overall, these results suggest that long-term frozen storage of raw fecal samples and the analysis of extracts within 8 weeks of extraction in 50% MeOH is sufficient for obtaining accurate STX quantifications in marine mammal fecal material without concerns about significant degradation. Full article
(This article belongs to the Special Issue Marine Toxins in Non-traditional Vectors)
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32 pages, 4220 KiB  
Article
The Common Sunstar Crossaster papposus—A Neurotoxic Starfish
Mar. Drugs 2021, 19(12), 695; https://doi.org/10.3390/md19120695 - 07 Dec 2021
Cited by 3 | Viewed by 3406
Abstract
Saxitoxins (STXs) are a family of potent neurotoxins produced naturally by certain species of phytoplankton and cyanobacteria which are extremely toxic to mammalian nervous systems. The accumulation of STXs in bivalve molluscs can significantly impact animal and human health. Recent work conducted in [...] Read more.
Saxitoxins (STXs) are a family of potent neurotoxins produced naturally by certain species of phytoplankton and cyanobacteria which are extremely toxic to mammalian nervous systems. The accumulation of STXs in bivalve molluscs can significantly impact animal and human health. Recent work conducted in the North Sea highlighted the widespread presence of various saxitoxins in a range of benthic organisms, with the common sunstar (Crossaster papposus) demonstrating high concentrations of saxitoxins. In this study, an extensive sampling program was undertaken across multiple seas surrounding the UK, with 146 starfish and 5 brittlestars of multiple species analysed for STXs. All the common sunstars analysed (n > 70) contained quantifiable levels of STXs, with the total concentrations ranging from 99 to 11,245 µg STX eq/kg. The common sunstars were statistically different in terms of toxin loading to all the other starfish species tested. Two distinct toxic profiles were observed in sunstars, a decarbomylsaxitoxin (dcSTX)-dominant profile which encompassed samples from most of the UK coast and an STX and gonyautoxin2 (GTX2) profile from the North Yorkshire coast of England. Compartmentalisation studies demonstrated that the female gonads exhibited the highest toxin concentrations of all the individual organs tested, with concentrations >40,000 µg STX eq/kg in one sample. All the sunstars, male or female, exhibited the presence of STXs in the skin, digestive glands and gonads. This study highlights that the common sunstar ubiquitously contains STXs, independent of the geographical location around the UK and often at concentrations many times higher than the current regulatory limits for STXs in molluscs; therefore, the common sunstar should be considered toxic hereafter. Full article
(This article belongs to the Special Issue Marine Toxins in Non-traditional Vectors)
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15 pages, 4587 KiB  
Article
Geographic Variations in the Toxin Profile of the Xanthid Crab Zosimus aeneus in a Single Reef on Ishigaki Island, Okinawa, Japan
Mar. Drugs 2021, 19(12), 670; https://doi.org/10.3390/md19120670 - 26 Nov 2021
Cited by 5 | Viewed by 1990
Abstract
Toxic crabs of the family Xanthidae contain saxitoxins (STXs) and/or tetrodotoxin (TTX), but the toxin ratio differs depending on their habitat. In the present study, to clarify within reef variations in the toxin profile of xanthid crabs, we collected specimens of the toxic [...] Read more.
Toxic crabs of the family Xanthidae contain saxitoxins (STXs) and/or tetrodotoxin (TTX), but the toxin ratio differs depending on their habitat. In the present study, to clarify within reef variations in the toxin profile of xanthid crabs, we collected specimens of the toxic xanthid crab Zosimus aeneus and their sampling location within a single reef (Yoshihara reef) on Ishigaki Island, Okinawa Prefecture, Japan, in 2018 and 2019. The STXs/TTX content within the appendages and viscera or stomach contents of each specimen was determined by instrumental analyses. Our findings revealed the existence of three zones in Yoshihara reef; one in which many individuals accumulate extremely high concentrations of STXs (northwestern part of the reef; NW zone), another in which individuals generally have small amounts of TTX but little STXs (central part of the reef; CTR zone), and a third in which individuals generally exhibit intermediate characteristics (southeastern part of the reef; SE zone). Furthermore, light microscopic observations of the stomach contents of crab specimens collected from the NW and CTR zones revealed that ascidian spicules of the genus Lissoclinum were dominant in the NW zone, whereas those of the genus Trididemnum were dominant in the CTR zone. Although the toxicity of these ascidians is unknown, Lissoclinum ascidians are considered good candidate source organisms of STXs harbored by toxic xanthid crabs. Full article
(This article belongs to the Special Issue Marine Toxins in Non-traditional Vectors)
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15 pages, 1971 KiB  
Article
Field Validation of the Southern Rock Lobster Paralytic Shellfish Toxin Monitoring Program in Tasmania, Australia
Mar. Drugs 2021, 19(9), 510; https://doi.org/10.3390/md19090510 - 08 Sep 2021
Cited by 2 | Viewed by 2306
Abstract
Paralytic shellfish toxins (PST) are found in the hepatopancreas of Southern Rock Lobster Jasus edwardsii from the east coast of Tasmania in association with blooms of the toxic dinoflagellate Alexandrium catenella. Tasmania’s rock lobster fishery is one of the state’s most important [...] Read more.
Paralytic shellfish toxins (PST) are found in the hepatopancreas of Southern Rock Lobster Jasus edwardsii from the east coast of Tasmania in association with blooms of the toxic dinoflagellate Alexandrium catenella. Tasmania’s rock lobster fishery is one of the state’s most important wild capture fisheries, supporting a significant commercial industry (AUD 97M) and recreational fishing sector. A comprehensive 8 years of field data collected across multiple sites has allowed continued improvements to the risk management program protecting public health and market access for the Tasmanian lobster fishery. High variability was seen in toxin levels between individuals, sites, months, and years. The highest risk sites were those on the central east coast, with July to January identified as the most at-risk months. Relatively high uptake rates were observed (exponential rate of 2% per day), similar to filter-feeding mussels, and meant that lobster accumulated toxins quickly. Similarly, lobsters were relatively fast detoxifiers, losing up to 3% PST per day, following bloom demise. Mussel sentinel lines were effective in indicating a risk of elevated PST in lobster hepatopancreas, with annual baseline monitoring costing approximately 0.06% of the industry value. In addition, it was determined that if the mean hepatopancreas PST levels in five individual lobsters from a site were <0.22 mg STX equiv. kg−1, there is a 97.5% probability that any lobster from that site would be below the bivalve maximum level of 0.8 mg STX equiv. kg−1. The combination of using a sentinel species to identify risk areas and sampling five individual lobsters at a particular site, provides a cost-effective strategy for managing PST risk in the Tasmanian commercial lobster fishery. Full article
(This article belongs to the Special Issue Marine Toxins in Non-traditional Vectors)
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18 pages, 5695 KiB  
Article
Intrabody Tetrodotoxin Distribution and Possible Hypothesis for Its Migration in Ribbon Worms Cephalothrix cf. simula (Palaeonemertea, Nemertea)
Mar. Drugs 2021, 19(9), 494; https://doi.org/10.3390/md19090494 - 29 Aug 2021
Cited by 9 | Viewed by 2362
Abstract
Tetrodotoxin (TTX) is a potent neurotoxin found in many marine and terrestrial animals, but only a few species, such as the ribbon worms of the genus Cephalothrix, accumulate it in extremely high concentrations. The intrabody distribution of TTX in highly toxic organisms [...] Read more.
Tetrodotoxin (TTX) is a potent neurotoxin found in many marine and terrestrial animals, but only a few species, such as the ribbon worms of the genus Cephalothrix, accumulate it in extremely high concentrations. The intrabody distribution of TTX in highly toxic organisms is of great interest because it helps researchers to understand the pathways by which the toxin migrates, accumulates, and functions in tissues. Using immunohistochemistry with anti-TTX antibodies, the authors of this study investigated the toxin’s distribution inside the organs, tissues, and cells of Cephalothrix cf. simula. The cell types of TTX-positive tissues were identified by light microscopy. The main sites of TTX accumulation occurred in the secretory cells of the integuments, the microvilli of the epidermal ciliary cells, cephalic glands, the glandular epithelia of the proboscises, the enterocytes of the digestive systems, and nephridia. Obtained data suggest the toxin migrates from the digestive system through blood vessels to target organs. TTX is excreted from the body through the nephridia and mucus of epidermal cells. Full article
(This article belongs to the Special Issue Marine Toxins in Non-traditional Vectors)
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10 pages, 1017 KiB  
Article
First Detection of Tetrodotoxins in the Cotylean Flatworm Prosthiostomum trilineatum
Mar. Drugs 2021, 19(1), 40; https://doi.org/10.3390/md19010040 - 18 Jan 2021
Cited by 9 | Viewed by 3063
Abstract
Several polyclad flatworm species are known to contain high levels of tetrodotoxin (TTX), but currently TTX-bearing flatworms seem to be restricted to specific Planocera lineages belonging to the suborder Acotylea. During our ongoing study of flatworm toxins, high concentrations of TTXs were detected [...] Read more.
Several polyclad flatworm species are known to contain high levels of tetrodotoxin (TTX), but currently TTX-bearing flatworms seem to be restricted to specific Planocera lineages belonging to the suborder Acotylea. During our ongoing study of flatworm toxins, high concentrations of TTXs were detected for the first time in the flatworm Prosthiostomum trilineatum, suborder Cotylea, from the coastal area of Hayama, Kanagawa, Japan. Toxin levels were investigated by high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS), revealing that this species contains comparable concentrations of toxins as seen in planocerid flatworms such as Planocera multitentaculata. This finding indicated that there may be other species with significant levels of TTXs. The distribution of TTXs among other flatworm species is thus of great interest. Full article
(This article belongs to the Special Issue Marine Toxins in Non-traditional Vectors)
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