Special Issue "Bioactivity and Chemical Ecological Interactions of Marine Toxins"

A special issue of Toxins (ISSN 2072-6651). This special issue belongs to the section "Marine and Freshwater Toxins".

Deadline for manuscript submissions: 28 February 2022.

Special Issue Editor

Prof. Dr. Allan Cembella
E-Mail Website
Guest Editor
Alfred-Wegner-Institut Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Am Handelshafen 12, 27570 Bremerhaven, Germany
Interests: chemical and molecular ecology of protists; genetics of toxin biosynthesis; toxinology and ecotoxicology of harmful microalgae; harmful algal blooms and marine food webs; marine phycotoxin dynamics and diversity; marine microbial biotechnology
Special Issues and Collections in MDPI journals

Special Issue Information

A vast array of marine organisms, including microeukaryotes and prokaryotes, metazoa, marine plants and macroalgae, are capable of biosynthezing natural bioactive substances. Many of these compounds are designated as toxins if they exhibit inimical effects on growth, behavior, or survival of specified target living systems. Toxicity is often defined with respect to bioassays (cultured cell and tissue lines, or whole animals, including humans), and thus may lead to erroneous inferences about the functional role of these compounds in situ in marine environments. The high global incidences of human poisoning due to the consumption of seafood contaminated with marine toxins, or exposure to poisonous or venomous creatures, underscore the critical need for studies to protect human health. Such research, however, provides little insight into the function and evolution of these toxins and their biosynthetic pathways.

Marine toxins are commonly assumed to have evolved as a mechanism for chemical defence against predation, to facilitate prey capture, or to modulate competitive interactions, but proof of this toxic strategy is frequently lacking. These bioactive substances may play more subtle and multivariate roles in species interactions, diversity and food web dynamics, rather than exclusively as “toxins.” The chemical ecology of marine toxins represents a frontier area of research and is worthy of more intensive investigation.

This Special Issue particularly welcomes contributions on defining linkages between bioactivity as determined in the laboratory and in marine micro- and mesocosms and the putative role of natural toxins in marine ecosystems.

Prof. Allan Cembella
Guest Editor

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 papers will be 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 double-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Toxins 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 2400 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

  • chemical ecology
  • allelopathy
  • marine toxin
  • ecotoxicology
  • phycotoxins
  • marine bioactives

Published Papers (3 papers)

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Research

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Article
Cell Death and Metabolic Stress in Gymnodinium catenatum Induced by Allelopathy
Toxins 2021, 13(7), 506; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13070506 - 20 Jul 2021
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Abstract
Allelopathy between phytoplankton species can promote cellular stress and programmed cell death (PCD). The raphidophyte Chattonella marina var. marina, and the dinoflagellates Margalefidinium polykrikoides and Gymnodinium impudicum have allelopathic effects on Gymnodinium catenatum; however, the physiological mechanisms are unknown. We evaluated [...] Read more.
Allelopathy between phytoplankton species can promote cellular stress and programmed cell death (PCD). The raphidophyte Chattonella marina var. marina, and the dinoflagellates Margalefidinium polykrikoides and Gymnodinium impudicum have allelopathic effects on Gymnodinium catenatum; however, the physiological mechanisms are unknown. We evaluated whether the allelopathic effect promotes cellular stress and activates PCD in G. catenatum. Cultures of G. catenatum were exposed to cell-free media of C. marina var. marina, M. polykrikoides and G. impudicum. The mortality, superoxide radical (O2●−) production, thiobarbituric acid reactive substances (TBARS) levels, superoxide dismutase (SOD) activity, protein content, and caspase-3 activity were quantified. Mortality (between 57 and 79%) was registered in G. catenatum after exposure to cell-free media of the three species. The maximal O2●− production occurred with C. marina var. marina cell-free media. The highest TBARS levels and SOD activity in G. catenatum were recorded with cell-free media from G. impudicum. The highest protein content was recorded with cell-free media from M. polykrikoides. All cell-free media caused an increase in the activity of caspase-3. These results indicate that the allelopathic effect in G. catenatum promotes cell stress and caspase-3 activation, as a signal for the induction of programmed cell death. Full article
(This article belongs to the Special Issue Bioactivity and Chemical Ecological Interactions of Marine Toxins)
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Article
Impacts of the Invasive Seaweed Asparagopsis armata Exudate on Energetic Metabolism of Rock Pool Invertebrates
Toxins 2021, 13(1), 15; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010015 - 25 Dec 2020
Cited by 3 | Viewed by 1180
Abstract
The marine red algae Asparagopsis armata is an invasive species gaining competitive advantage by releasing large amounts of toxic compounds to the surrounding invaded area. The main objective of this study was to evaluate the effects of this invasive seaweed on marine invertebrates [...] Read more.
The marine red algae Asparagopsis armata is an invasive species gaining competitive advantage by releasing large amounts of toxic compounds to the surrounding invaded area. The main objective of this study was to evaluate the effects of this invasive seaweed on marine invertebrates by exposing the common prawn Palaemon elegans and the marine snail Gibbula umbilicalis to the exudate of this seaweed. The seaweed was collected and placed in a tank for 12 h in the dark in a 1:10 ratio. Afterwards the seawater medium containing the released secondary metabolites was collected for further testing. Lethal and sublethal effects of A. armata were investigated. Biochemical biomarker responses associated with energy metabolism (lactate dehydrogenase, LDH; electron transport system activity, ETS; lipid, protein and carbohydrate content) were analysed. The biomarker responses showed physiological status impairment of invertebrates after exposure to low concentrations of this algal exudate. The highest concentrations of exudate significantly increased lipid content in both organisms. In the shrimp, protein content, ETS, and LDH were also significantly increased. By contrast, these parameters were significantly decreased in G. umbilicalis. A behavioural impairment was also observed in G. umbilicalis exposed to A. armata exudate, reducing feeding consumption. These results represent an important step in the research of natural toxic exudates released to the environment and prospective effects of this seaweed in invaded communities under increasing global change scenarios. Full article
(This article belongs to the Special Issue Bioactivity and Chemical Ecological Interactions of Marine Toxins)
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Review

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Review
Paralytic Shellfish Toxins (PST)-Transforming Enzymes: A Review
Toxins 2020, 12(5), 344; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins12050344 - 22 May 2020
Cited by 6 | Viewed by 1640
Abstract
Paralytic shellfish toxins (PSTs) are a group of toxins that cause paralytic shellfish poisoning through blockage of voltage-gated sodium channels. PSTs are produced by prokaryotic freshwater cyanobacteria and eukaryotic marine dinoflagellates. Proliferation of toxic algae species can lead to harmful algal blooms, during [...] Read more.
Paralytic shellfish toxins (PSTs) are a group of toxins that cause paralytic shellfish poisoning through blockage of voltage-gated sodium channels. PSTs are produced by prokaryotic freshwater cyanobacteria and eukaryotic marine dinoflagellates. Proliferation of toxic algae species can lead to harmful algal blooms, during which seafood accumulate high levels of PSTs, posing a health threat to consumers. The existence of PST-transforming enzymes was first remarked due to the divergence of PST profiles and concentrations between contaminated bivalves and toxigenic organisms. Later, several enzymes involved in PST transformation, synthesis and elimination have been identified. The knowledge of PST-transforming enzymes is necessary for understanding the processes of toxin accumulation and depuration in mollusk bivalves. Furthermore, PST-transforming enzymes facilitate the obtainment of pure analogues of toxins as in natural sources they are present in a mixture. Pure compounds are of interest for the development of drug candidates and as analytical reference materials. PST-transforming enzymes can also be employed for the development of analytical tools for toxin detection. This review summarizes the PST-transforming enzymes identified so far in living organisms from bacteria to humans, with special emphasis on bivalves, cyanobacteria and dinoflagellates, and discusses enzymes’ biological functions and potential practical applications. Full article
(This article belongs to the Special Issue Bioactivity and Chemical Ecological Interactions of Marine Toxins)
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