6. Harmful marine algal blooms and climate change: progress on a formidable predictive challenge

Hallegraeff, GM

doi:10.1515/9783110333596-008

Cited by 3 publications

(10 citation statements)

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“…Bivalve molluscs may be contaminated with marine biotoxins produced by microalgae and these toxins are an important cause of seafood intoxications, with symptoms that vary from mild diarrhoea to permanent neuropathy or death. Their presence is expanding worldwide, for reasons that are not fully understood, but appear to be linked to climate change, eutrophication and international trade (Hallegraef, 2015).…”

Section: Introductionmentioning

confidence: 99%

Derivation of toxicity equivalency factors for marine biotoxins associated with Bivalve Molluscs

Botana

Heß

Munday

et al. 2017

Trends in Food Science & Technology

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Background Seafood toxins pose an important risk to human health, and maximum levels were imposed by regulatory authorities throughout the world. Several toxin groups are known, each one with many analogues of the major toxin. Regulatory limits are set to ensure that commercially available seafood is not contaminated with unsafe levels. Scope and Approach The mouse bioassay was used to measure the toxicity in seafood extracts to determine if a sample exceeded regulatory limits. The advantage of this approach was to provide an estimation of the total toxicity in the sample. As instrumental methods of analysis advance and serve as replacements to the mouse bioassay, the challenge is translating individual toxin concentrations into toxicity to determine whether regulatory limits have been exceeded. Such analyses provide accurate quantitation of the toxin Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site. analogues, by they have widely dissimilar potencies. Thus, knowledge of the relative toxicities is required for risk assessment and determining overall toxicity. The ratios between the toxicity of the analogues and that of a reference compound within the same toxin group are termed "Toxicity Equivalency Factors" (TEFs). Key Findings and Conclusions In this document, the requirements for determining TEFs of toxin analogues are described, and recommendations for research to further refine TEFs are identified. The proposed TEFs herein, when applied to toxin analogue concentrations determined using analytical methods, will provide a base to determine overall toxicity, thereby protecting human health. Highlights ► Marine toxins TEF are revised according to recent toxicology studies. ► TEF for each toxin group are proposed. ► The proposed TEF were agreed by a joint FAO-WHO working group.

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Section: Introductionmentioning

confidence: 99%

Derivation of toxicity equivalency factors for marine biotoxins associated with Bivalve Molluscs

Botana

Heß

Munday

et al. 2017

Trends in Food Science & Technology

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“…However, other marine toxin groups with potentially serious health consequences remain largely unregulated. The majority of toxins are produced naturally by species of marine harmful algal blooms (mHABs), with others associated with bacteria [76]. Cyanobacterial harmful algal blooms (CHABs) are distributed widely, most notably in freshwater [77], posing a substantial threat to both drinking and recreational water.…”

Section: Aquatic Food and Water Safetymentioning

confidence: 99%

“…Expansion of marine toxin-producing mHABs over recent decades is well recognised and has been linked to ballast water transportation, eutrophication, and climate change [76]. Climatic change in particular is recognised as a key factor concerning the frequency and severity of natural aquatic toxin occurrence [79,83].…”

Section: Aquatic Food and Water Safetymentioning

confidence: 99%

“…Climatic change in particular is recognised as a key factor concerning the frequency and severity of natural aquatic toxin occurrence [79,83]. Changes in both mean and extreme values of temperature, light, ocean acidification, wind, precipitation, currents, and nutrients may all contribute to changes in blooms, including germination and growth rates, geographical expansion, as well as cell toxicities, shellfish toxicity [83,84], and incidents of human intoxications [76]. Similarly, expansion of CHABs is influenced by many factors, including iron availability, light, hydrological changes, storm events, drought, precipitation, and industrial pollution [85].…”

Section: Aquatic Food and Water Safetymentioning

confidence: 99%

“…Regulations (e.g., food safety, environmental exposure) are absent for the majority of emerging aquatic toxins and, given the limited understanding regarding toxin production and occurrence under climatic change conditions [78], environmental modelling approaches are needed to forecast spatial and temporal aquatic toxicity and related human health hazards [81]. To do this we need to link our developing understanding of environmental impacts on toxin production with the ability to combine improved detection and forecasting systems, including in situ ocean observation systems, highly specific and sensitive chemical detection tools, satellite data, and other biological observations into effective operational modelling regimes [76,82].…”

Section: Box 4 Tetrodotoxin and Vibriomentioning

confidence: 99%

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Friends or Foes? Emerging Impacts of Biological Toxins

Clark

Casewell

Elliott

et al. 2019

Trends in Biochemical Sciences

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Toxins are substances produced from biological sources (e.g., animal, plants, microorganisms) that have deleterious effects on a living organism. Despite the obvious health concerns of being exposed to toxins, they are having substantial positive impacts in a number of industrial sectors. Several toxin-derived products are approved for clinical, veterinary, or agrochemical uses. This review sets out the case for toxins as 'friends' that are providing the basis of novel medicines, insecticides, and even nucleic acid sequencing technologies. We also discuss emerging toxins ('foes') that are becoming increasingly prevalent in a range of contexts through climate change and the globalisation of food supply chains and that ultimately pose a risk to health. Toxins and Toxinology In the natural world, toxins are employed for diverse purposes, from the prey-incapacitating molecules found in snake, spider, and cone snail venom, to the defensive compounds harboured by numerous poisonous plant and animal species. While the consequences of human intoxication can be severe (Box 1), the functional diversity of biological toxins has led to their frequent use as experimental tools for studying physiological and pharmacological mechanisms (e.g., synaptic transmission, ion channel subtypes) (Figure 1). Toxinology involves the identification, characterisation, production, and engineering of biological toxins along with their application or repurposing as research tools and clinical products. As such, toxinology encompasses the study of the evolution, chemistry, biology, and clinical effects of toxins and includes potential biotechnological and/or therapeutic applications. Experimental applications of toxins as tools for physiologists go back a long time, including Claude Bernard's experiments in the 1800s with curare to demonstrate the existence of chemical signalling between nerves and muscles [2], and Henry Dale's use of muscarine and nicotine to show different subtypes of receptors for acetylcholine [3]. Snake toxins were critical for the first isolation of a receptor for a neurotransmitter [a-bungarotoxin and nicotinic acetylcholine receptors (nAChRs)] [4]. Recently, peptide toxins have been very useful in teasing out the functional importance of different subtypes of ion channels that are critical for neuronal function and cellular signalling [5-7]. An increasing number of toxins are now transitioning from the laboratory to the clinic and the balance of research in this aspect of toxinology is shifting from the classical development of anti-toxins and anti-venoms towards drug discovery [8,9]. The attraction of toxins for drug discovery lies in their often unique selectivity of their biological effects coupled with high potency. Toxic plant alkaloids were the first source of toxin-derived therapeutics, notably

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Toxicological Perspective on Climate Change: Aquatic Toxins

Botana

2016

Chem. Res. Toxicol.

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In recent years, our group and several others have been describing the presence of new, not previously reported, toxins of high toxicity in vectors that may reach the human food chain. These include tetrodotoxin in gastropods in the South of Europe, ciguatoxin in fish in the South of Spain, palytoxin in mussels in the Mediterranean Sea, pinnatoxin all over Europe, and okadaic acid in the south of the U.S. There seem to be new marine toxins appearing in areas that are heavy producers of seafood, and this is a cause of concern as most of these new toxins are not included in current legislation and monitoring programs. Along with the new toxins, new chemical analogues are being reported. The same phenomenom is being recorded in freshwater toxins, such as the wide appearance of cylindrospermopsin and the large worldwide increase of microcystin. The problem that this phenomenon, which may be linked to climate warming, poses for toxicologists is very important not only because there is a lack of chronic studies and an incomplete comprehension of the mechanism driving the production of these toxins but also because the lack of a legal framework for them allows many of these toxins to reach the market. In some cases, it is very difficult to control these toxins because there are not enough standards available, they are not always certified, and there is an insufficient understanding of the toxic equivalency factors of the different analogues in each group. All of these factors have been revealed and grouped through the massive increase in the use of LC-MS as a monitoring tool, legally demanded, creating more toxicological problems.

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6. Harmful marine algal blooms and climate change: progress on a formidable predictive challenge

Cited by 3 publications

References 0 publications

Derivation of toxicity equivalency factors for marine biotoxins associated with Bivalve Molluscs

Derivation of toxicity equivalency factors for marine biotoxins associated with Bivalve Molluscs

Friends or Foes? Emerging Impacts of Biological Toxins

Toxicological Perspective on Climate Change: Aquatic Toxins

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