Palytoxin

The marine microalgae Ostreopsis cf. ovata are a well-known producer of palytoxin (PlTXs) analogues, i.e. ovatoxins (OVTXs) among others, which arouse concern for animal and human health. Both in field and laboratory studies, presence of OVTXs, detected in species directly feeding on O. cf. ovata, was frequently correlated with impairment on organisms' physiology, development and behaviour, while similar knowledge is still lacking for animals feeding on contaminated preys. In this study, transfer and toxicity of OVTXs were evaluated in an exposure experiment, in which gilthead seabream Sparus aurata was fed with bivalve mussel Mytilus galloprovincialis, contaminated by a toxic strain of O...

Blooms of the dinoflagellate Ostreopsis cf. ovata are regularly associated with human intoxications that are attributed to ovatoxins (OVTXs), the main toxic compounds produced this organism and close analogs to palytoxin (PlTX). Unlike for PlTX, information on OVTXs'toxicity are scarce due to the absence of commercial standards. Extracts from two cultures of Mediterranean strains of O. cf. ovata (MCCV54 and MCCV55), two fractions containing or not OVTXs (prepared from the MCCV54 extract) and OVTX-a and -d (isolated from the MCCV55 extract) were generated...

We describe a case of a young male who presented to the emergency department with unilateral eye pain, blurred vision, conjunctival injection, and ocular pH of 9, one day after direct ocular exposure to palytoxin (PTX) from coral in a home saltwater fish tank. Although uncommon, ocular PTX toxicity is a potentially vision-threatening condition that requires prompt recognition. This case report documents the successful management of presumed ocular PTX exposure and suggests additional workup and treatment considerations for future patients...

Temperatures and temperature anomalies have been increasing in the sub-tropical regions of Aotearoa New Zealand and these changes may impact on harmful algal bloom (HAB) events. Benthic and epiphytic dinoflagellates, particularly the toxin producers, are the focus of this study as it is predicted that under future climate conditions they may produce more toxins or marine animals may become more susceptible to them. The results of past expeditions to Rangitāhua Kermadec Islands and sampling trips to Northland, Aotearoa New Zealand, are summarised and the results of the most recent trips to both regions are presented...

Palytoxin is considered one of the most potent biotoxins. As palytoxin-induced cancer cell death mechanisms remain to be elucidated, we investigated this effect on various leukemia and solid tumor cell lines at low picomolar concentrations. As palytoxin did not affect the viability of peripheral blood mononuclear cells (PBMC) from healthy donors and did not create systemic toxicity in zebrafish, we confirmed excellent differential toxicity. Cell death was characterized by a multi-parametric approach involving the detection of nuclear condensation and caspase activation assays...

Palytoxin (PTX) is a potent neurotoxin found in marine animals that can cause serious symptoms such as muscle contractions, haemolysis of red blood cells and potassium leakage. Despite years of research, very little is known about the mechanism of PTX. However, recent advances in the field of cryoEM, specifically the use of microcrystal electron diffraction (MicroED), have allowed us to determine the structure of PTX. It was discovered that PTX folds into a hairpin motif and is able to bind to the extracellular gate of Na,K-ATPase, which is responsible for maintaining the electrochemical gradient across the plasma membrane...

This study aimed to improve the understanding of the nutrient modulation of Ostreopsis cf. ovata toxin content. During the 2018 natural bloom in the NW Mediterranean, the total toxin content (up to ca. 57.6 ± 7.0 pg toxin cell-1 ) varied markedly. The highest values often coincided with elevated O. cf. ovata cell abundance and with low inorganic nutrient concentrations. The first culture experiment with a strain isolated from that bloom showed that cell toxin content was higher in the stationary than in the exponential phase of the cultures; phosphate- and nitrate-deficient cells exhibited similar cell toxin variability patterns...

Analogues of palytoxin (PLTX), one of the most potent marine biotoxins, are produced by some species of the marine dinoflagellates of the genus Ostreopsis . The proliferation of these species in different coastal zones represents a potential threat of seafood poisoning in humans because the produced toxins can be transferred through marine food webs. Thus, the determination of the concentration of PLTX analogues (ovatoxins-OVTXs, ostreocins-OSTs and isobaric PLTX) in different matrices (seawater, marine fauna, etc...

It is important to decipher the diversity and distribution of benthic dinoflagellates, as there are many morphologically indistinct taxa that differ from one another in production of potent toxins. To date, the genus Ostreopsis comprises twelve described species, of which seven are potentially toxic and produce compounds presenting a threat to human and environmental health. In this study, isolates previously identified as "Ostreopsis sp. 3" were sampled from the area where it was first reported, Rarotonga, Cook Islands, and have been taxonomically and phylogenetically characterised as Ostreopsis tairoto sp...

Several species of microalgae can produce potent phycotoxins that negatively affect aquatic organisms and their consumers following different exposure routes, as well as toxicokinetic (TK) and toxicodynamic (TD) processes. Benthic organisms are especially vulnerable as they are exposed to both benthic and planktonic species causative of harmful algal blooms (HABs). While benthic algae can come into direct contact with annelids during substrate remobilization, planktonic cells can settle to the bottom mostly during senescence and/or encystment stages, and in shallow and calm waters...

The frequent occurrence of marine dinoflagellates producing palytoxin (PLTX) or okadaic acid (OA) raises concern for the possible co-presence of these toxins in seafood, leading to additive or synergistic adverse effects in consumers. Thus, the acute oral toxicity of PLTX and OA association was evaluated in mice: groups of eight female CD-1 mice were administered by gavage with combined doses of PLTX (30, 90 or 270 μg/kg) and OA (370 μg/kg), or with each individual toxin, recording signs up to 24 h (five mice) and 14 days (three mice)...

This paper summarizes the research conducted by the partners of the EU co-funded CoCliME project to ascertain the ecological, human health and economic impacts of Ostreopsis (mainly O. cf. ovata) blooms in the NW Mediterranean coasts of France, Monaco and Spain. This knowledge is necessary to design strategies to prevent, mitigate and, if necessary, adapt to the impacts of these events in the future and in other regions. Ostreopsis proliferations in the Mediterranean have been related to massive mortalities of benthic organisms and to symptoms of respiratory and cutaneous irritation in humans...

Human intoxications in the Mediterranean Sea have been linked to blooms of the dinoflagellate Ostreopsis cf. ovata, producer of palytoxin (PlTX)-like toxins called ovatoxins (OVTXs). Exposure routes include only inhalation and contact, although PlTX-poisoning by seafood has been described in tropical regions. To address the impact of OVTXs on the intestinal barrier, dinoflagellate extracts, purified OVTX-a and -d and PlTX were tested on differentiated Caco-2 cells. Viability, inflammatory response and barrier integrity were recorded after 24 h treatment...

Among marine biotoxins, palytoxins (PlTXs) and cyclic imines (CIs), including spirolides, pinnatoxins, pteriatoxins, and gymnodimines, are not managed in many countries, such as the USA, European nations, and South Korea, because there are not enough poisoning cases or data for the limits on these biotoxins. In this article, we review unregulated marine biotoxins (e.g., PlTXs and CIs), their toxicity, causative phytoplankton species, and toxin extraction and detection protocols. Due to global warming, the habitat of the causative phytoplankton has expanded to the Asia-Pacific region...

Palytoxin (PLTX) is a polyether marine toxin isolated from sea anemones. It is one of the most toxic nonprotein substances, causing many people to be poisoned every year and to die in severe cases. Despite its known impact on Na+ ,K+ -ATPase, much still remains unclear about PLTX's mechanism of action. Here, we tested different concentrations of PLTX on HaCaT cells and studied its distributions in cells, its impact on gene expression, and the associated pathways via proteomics combined with bioinformatics tools...

Ostreopsis cf. ovat a is a benthic dinoflagellate known to produce palytoxin (PLTX) and its analogues. Recent investigations suggested the production of unknown toxins by a Mediterranean strain. In the present work, two new families of toxins, potentially novel in their structures, were purified from this same Mediterranean strain of Ostreopsis cf. ovata . The low amount of material isolated only allowed for acquisition of high-resolution mass spectrometry data and the evaluation of their cytotoxicity to human lung cancer cells...

Purpose: This case report describes the therapeutic management of a 61-year-old male who experienced aquarium coral keratoconjunctivitis caused by exposure to palytoxin and provides an additional resource to raise awareness and treat patients with ocular exposure to palytoxin. Observations: A 61-year-old male inadvertently touched his left eye while cleaning an aquarium. Within 24 hours, pain, redness and visual blurring was noted. After 48 hours his best corrected visual acuity was measured at 20/25 on the right eye and 20/200 on the left...

Marine phycotoxins associated with paralytic shellfish poisoning (PSP), diarrhetic shellfish poisoning (DSP), amnesic shellfish poisoning (ASP), neurotoxic shellfish poisoning (NSP), ciguatera fish poisoning (CFP), tetrodotoxin (TTX), palytoxin (PLTX) and neurotoxin β-N-methylamino-L-alanine (BMAA) have been investigated and routinely monitored along the coast of China. The mouse bioassay for monitoring of marine toxins has been progressively replaced by the enzyme-linked immunosorbent assay (ELISA) and liquid chromatography tandem mass spectrometry (LC-MS/MS), which led to the discovery of many new hydrophilic and lipophilic marine toxins...

Palytoxin is a potent toxin found in zoanthid species, a popular decorative coral used in private aquaria. Inappropriate cleaning procedure may lead to palytoxin poisoning by dermal contact and inhalation of water aerosols, affecting several organ systems. This is a case report of three family members admitted to a hospital with symptoms compatible with palytoxin poisoning after cleaning an aquarium. One of them had remarkable respiratory distress and needed oxygen therapy.

Palytoxin (PTX) is produced by corals such as zoanthid corals. Here we present a case of bilateral PTX-induced keratoconjunctivitis. A 63-year-old man presented to the emergency department with symptoms of red eye, purulent discharge, and foreign body sensation in both eyes. On slit lamp examination, epithelial defects in both eyes with a ring-shaped corneal stromal infiltrate in the right eye and a marginal stromal infiltrate in the left eye were noted. High-resolution anterior segment optical coherence tomography (HR-AS-OCT) showed stromal hyperreflectivity and Descemet folds...