Integrative Inducer Intervention and Transcriptomic Analyses Reveal the Metabolism of Paralytic Shellfish Toxins in Azumapecten farreri.

Paralytic shellfish toxins (PSTs) are widely distributed neurotoxins, and the PST metabolic detoxification mechanism in bivalves has received increasing attention. To reveal the effect of phase I (cytochrome P450)-II (GST)-III (ABC transport) metabolic systems on the PST metabolism in Azumapecten farreri, this study amplified stress on the target systems using rifampicin, dl-α-tocopherol, and colchicine; measured PST levels; and conducted transcriptomic analyses. The highest toxin content reached 1623.48 µg STX eq/kg in the hepatopancreas and only 8.8% of that in the gills. Inducer intervention significantly decreased hepatopancreatic PST accumulation. The proportional reductions in the rifampicin-, dl-α-tocopherol-, and colchicine-induced groups were 55.3%, 50.4%, and 36.1%, respectively. Transcriptome analysis showed that 11 modules were significantly correlated with PST metabolism (six positive/five negative), with phase I CYP450 and phase II glutathione metabolism significantly enriched in negatively correlated pathways. Twenty-three phase I-II-III core genes were further validated using qRT-PCR and correlated with PST metabolism, revealing that CYP46A1, CYP4F6, GSTM1, and ABCF2 were significantly correlated, while CYP4F11 and ABCB1 were indirectly correlated. In conclusion, phase I-II-III detoxification enzyme systems jointly participate in the metabolic detoxification of PSTs in A. farreri. This study provides key data support to profoundly elucidate the PST metabolic detoxification mechanism in bivalves.

Distribution patterns and co-occurrence network of eukaryotic algae in different salinity waters of Yuncheng Salt Lake, China.

The community structure and co-occurrence pattern of eukaryotic algae in Yuncheng Salt Lake were analyzed based on marker gene analysis of the 18S rRNA V4 region to understand the species composition and their synergistic adaptations to the environmental factors in different salinity waters. The results showed indicated that the overall algal composition of Yuncheng Salt Lake showed a Chlorophyta-Pyrrophyta-Bacillariophyta type structure. Chlorophyta showed an absolute advantage in all salinity waters. In addition, Cryptophyta dominated in the least saline waters; Pyrrophyta and Bacillariophyta were the dominant phyla in the waters with salinity ranging from 13.2 to 18%. Picochlorum, Nannochloris, Ulva, and Tetraselmis of Chlorophyta, Biecheleria and Oxyrrhis of Pyrrophyta, Halamphora, Psammothidium, and Navicula of Bacillariophyta, Guillardia and Rhodomonas of Cryptophyta were not observed in previous surveys of the Yuncheng Salt Lake, suggesting that the algae are undergoing a constant turnover as the water environment of the Salt Lake continues to change. The network diagram demonstrated that the algae were strongly influenced by salinity, NO3-, and pH, changes in these environmental factors would lead to changes in the algal community structure, thus affecting the stability of the network structure.

What's in a name? Political and economic concepts differ in social media references to harmful algae blooms.

Policies and management decisions in the marine environment are driven in part by public sentiment which can grow more intense during hazard events like Harmful Algae Blooms (HABs). The public conversations on social media sites like Twitter (before X) reveal the polarized nature of HABs through nuanced language and sentiment. This article uses mixed methods of machine learned topic modeling and inductive qualitative coding to describe the ways the long-term 2017-2019 Karenia brevis "red tide" bloom were politicized across Florida's South West coast. It finds that there are topical differences in keywords related to place (e.g. beach, Florida, coast), agent (individual or organization), and epistemic values (reliance on scientific and/or media reports). These topical differences demonstrate different levels of politicization and partisanship in qualitative analysis. Conceptually, this research demonstrates the ways different dimensions of a long-duration marine hazard can be polarized. Regarding management, this research provides insights to political and organizational stakeholders and the gaps in the discourse shaping marine hazards which can be used to strategically guide future social media engagement to manage politicization. What if all the careful work that resource and environmental managers do can be undone by simple, seemingly uncontroversial words? In an era of increased environmental and marine distress-coupled with short format communication-the ways environmental managers choose their words is crucial, even between ostensibly inconsequential nouns like "red tide" or "algae bloom." Policies and management decisions in the marine environment are driven in part by public sentiment which can grow more intense during hazard events like Harmful Algae Blooms (HABs). The public conversations on social media sites like Twitter (before X) reveal the polarized nature of HABs through nuanced language and sentiment. This article relies on mining social media posts, and uses mixed methods of machine-learned topic modeling and human-driven inductive qualitative coding to describe the ways the long-term 2017-2019 Karenia brevis "red tide" blooms were politicized across Florida's South West coast. It finds that there are topical differences in keywords related to place (e.g. beach, Florida, coast), agent (individual or organization), and epistemic values (reliance on scientific and/or media reports). These topical differences demonstrate different levels of politicization and partisanship in qualitative analysis. Conceptually, this research demonstrates the ways different dimensions of a long-duration marine hazard can be polarized. Regarding management, this research provides insights to political and organizational stakeholders and the gaps in the discourse shaping marine hazards which can be used to strategically guide future social media engagement to manage politicization.

Oxytoxaceae are prorocentralean rather than peridinialean dinophytes and taxonomic clarification of heterotrophic Oxytoxum lohmannii (≡ "Amphidinium" crassum) by epitypification.

During evolution of Dinophyceae, size reduction of the episome has occurred in several lineages (including unarmoured Amphidiniales and armoured Prorocentrales). One such species is Amphidinium crassum, whose taxonomic identity is elusive though showing morphological similarities with Oxytoxaceae (currently placed in armoured Peridiniales). Plankton samples were taken at the type locality of A. crassum in Kiel Bight (Baltic Sea) in order to establish monoclonal strains. The protist material was examined in detail using light and electron microscopy, and a long (2984 bp) ribosomal RNA sequence gained was part of a taxon sample comprising 206 specimen vouchers and representing the known molecular diversity of Dinophyceae. Cells of A. crassum were ovoid and exhibited a plate pattern po, 4', 1a, 6'', 5c, 4s, 5''', 1''''. In the molecular phylogeny, the species seemed to belong neither to Amphidiniales nor to Peridiniales but to Prorocentrales and clustered with other representatives of Oxytoxaceae. The morphological diversity of Prorocentrales appears thus expanded, and the group may include a number of previously unrecognised representatives unusually having five postcingular and only a single antapical plate. The taxonomic identity of A. crassum is clarified by epitypification, and the species notably exhibits both an apical pore and an additional epithecal pore.

Marine Bioluminescence: Simulation of Dynamics within a Pump-Through Bathyphotometer.

Bioluminescence is light produced by organisms through chemical reactions. In most cases, bioluminescent organisms produce light in response to mechanical stimulation, including from shear around objects moving in the water. Many phytoplankton and zooplankton are capable of producing bioluminescence, which is commonly measured as bioluminescence potential, defined as mechanically stimulated light measured inside of a chambered pump-through bathyphotometer. We have developed a numerical model of a pump-through bathyphotometer and simulated flow using Lagrangian particles as an approximation for bioluminescent marine plankton taxa. The results indicate that all particles remain in the detection chamber for a residence time of at least 0.25 s. This suggests that the total first flash of bioluminescent autotrophic and heterotrophic dinoflagellates will be measured based on the existing literature regarding their flash duration. We have found low sensitivity of particle residence time to variations in particle size, density, or measurement depth. In addition, the results show that a high percentage of organisms may experience stimulation well before the detection chamber, or even multiple stimulations within the detection chamber. The results of this work serve to inform the processing of current bioluminescent potential data and assist in the development of future instruments.

New plastids, old proteins: repeated endosymbiotic acquisitions in kareniacean dinoflagellates.

Dinoflagellates are a diverse group of ecologically significant micro-eukaryotes that can serve as a model system for plastid symbiogenesis due to their susceptibility to plastid loss and replacement via serial endosymbiosis. Kareniaceae harbor fucoxanthin-pigmented plastids instead of the ancestral peridinin-pigmented ones and support them with a diverse range of nucleus-encoded plastid-targeted proteins originating from the haptophyte endosymbiont, dinoflagellate host, and/or lateral gene transfers (LGT). Here, we present predicted plastid proteomes from seven distantly related kareniaceans in three genera (Karenia, Karlodinium, and Takayama) and analyze their evolutionary patterns using automated tree building and sorting. We project a relatively limited ( ~ 10%) haptophyte signal pointing towards a shared origin in the family Chrysochromulinaceae. Our data establish significant variations in the functional distributions of these signals, emphasizing the importance of micro-evolutionary processes in shaping the chimeric proteomes. Analysis of plastid genome sequences recontextualizes these results by a striking finding the extant kareniacean plastids are in fact not all of the same origin, as two of the studied species (Karlodinium armiger, Takayama helix) possess plastids from different haptophyte orders than the rest.

Revealing the algicidal characteristics of Maribacter dokdonensis: An investigation into bacterial strain P4 isolated from Karenia mikimotoi bloom water.

Harmful algal blooms (HABs) are a global environmental concern, causing significant economic losses in fisheries and posing risks to human health. Algicidal bacteria have been suggested as a potential solution to control HABs, but their algicidal efficacy is influenced by various factors. This study aimed to characterize a novel algicidal bacterium, Maribacter dokdonensis (P4), isolated from a Karenia mikimotoi (Hong Kong strain, KMHK) HAB and assess the impact of P4 and KMHK's doses, growth phase, and algicidal mode and the axenicity of KMHK on P4's algicidal effect. Our results demonstrated that the algicidal effect of P4 was dose-dependent, with the highest efficacy at a dose of 25% v/v. The study also determined that P4's algicidal effect was indirect, with the P4 culture and the supernatant, but not the bacterial cells, showing significant effects. The algicidal efficacy was higher when both P4 and KMHK were in the stationary phase. Furthermore, the P4 culture at the log phase could effectively kill KMHK cells at the stationary phase, with higher algicidal efficacy in the bacterial culture than that of the supernatant alone. Interestingly, P4's algicidal efficacy was significantly higher when co-culturing with xenic KMHK (~90% efficacy at day 1) than that with the axenic KMHK (~50% efficacy at day 1), suggesting the presence of other bacteria could regulate P4's algicidal effect. The bacterial strain P4 also exhibited remarkable algicidal efficacy on four other dinoflagellate species, particularly the armored species. These results provide valuable insights into the algicidal effect of M. dokdonensis on K. mikimotoi and on their interactions.

Photosynthesis and other factors affecting the establishment and maintenance of cnidarian-dinoflagellate symbiosis.

Coral growth depends on the partnership between the animal hosts and their intracellular, photosynthetic dinoflagellate symbionts. In this study, we used the sea anemone Aiptasia, a laboratory model for coral biology, to investigate the poorly understood mechanisms that mediate symbiosis establishment and maintenance. We found that initial colonization of both adult polyps and larvae by a compatible algal strain was more effective when the algae were able to photosynthesize and that the long-term maintenance of the symbiosis also depended on photosynthesis. In the dark, algal cells were taken up into host gastrodermal cells and not rapidly expelled, but they seemed unable to reproduce and thus were gradually lost. When we used confocal microscopy to examine the interaction of larvae with two algal strains that cannot establish stable symbioses with Aiptasia, it appeared that both pre- and post-phagocytosis mechanisms were involved. With one strain, algae entered the gastric cavity but appeared to be completely excluded from the gastrodermal cells. With the other strain, small numbers of algae entered the gastrodermal cells but appeared unable to proliferate there and were slowly lost upon further incubation. We also asked if the exclusion of either incompatible strain could result simply from their cells' being too large for the host cells to accommodate. However, the size distributions of the compatible and incompatible strains overlapped extensively. Moreover, examination of macerates confirmed earlier reports that individual gastrodermal cells could expand to accommodate multiple algal cells. This article is part of the theme issue 'Sculpting the microbiome: how host factors determine and respond to microbial colonization'.

A comparison of two gene regions for assessing community composition of eukaryotic marine microalgae from coastal ecosystems.

Two gene regions commonly used to characterise the diversity of eukaryotic communities using metabarcoding are the 18S ribosomal DNA V4 and V9 gene regions. We assessed the effectiveness of these two regions for characterising diverisity of coastal eukaryotic microalgae communities (EMCs) from tropical and temperate sites. We binned amplicon sequence variants (ASVs) into the high level taxonomic groups: dinoflagellates, pennate diatoms, radial centric diatoms, polar centric diatoms, chlorophytes, haptophytes and 'other microalgae'. When V4 and V9 generated ASV abundances were compared, the V9 region generated a higher number of raw reads, captured more diversity from all high level taxonomic groups and was more closely aligned with the community composition determined using light microscopy. The V4 region did resolve more ASVs to a deeper taxonomic resolution within the dinoflagellates, but did not effectively resolve other major taxonomic divisions. When characterising these communities via metabarcoding, the use of multiple gene regions is recommended, but the V9 gene region can be used in isolation to provide high-level community biodiversity to reflect relative abundances within groups. This approach reduces the cost of sequencing multiple gene regions whilst still providing important baseline ecosystem function information.

Long-term response of interspecific competition among three typical bloom-forming species to changes in phosphorus and temperature.

Phosphorus and temperature play an important role in the succession of diatom-dinoflagellate blooms. However, there is little long-term research on interspecific competition based on phosphorus source and temperature. Here, interspecific competition among Skeletonema costatum, Prorocentrum donghaiense and Karenia mikimotoi was studied using trialgal laboratory co-cultures under different phosphorus and temperature conditions. These results suggest that S. costatum and P. donghaiense alternated as competing dominant species during the experimental period, which coincides with the different phosphorus conditions. However, K. mikimotoi growth was significantly inhibited throughout the experiment. We suggest that this may be due to different algal requirements for phosphorus, optimal growth temperatures, and possible allelopathic effects. This study provides a comprehensive mechanism of interspecific competition between diatom-dinoflagellate in response to phosphorus and temperature and elucidates the seasonal succession of diatom-dinoflagellate from late spring to early summer in the Changjiang River Estuary and the adjacent East China Sea.

New azaspiracid analogues detected as bi-charged ions in Azadinium poporum (Amphidomataceae, Dinophyceae) isolated from Japanese coastal waters.

Lipophilic marine biotoxin azaspiracids (AZAs) are produced by dinoflagellates Azadinium and Amphidoma. Recently, several strains of Azadinium poporum were isolated from Japanese coastal waters, and detailed toxin profiles of two strains (mdd421 and HM536) among them were clarified by several detection techniques on liquid chromatography-tandem mass spectrometry (LC-MS/MS) and liquid chromatography-quadrupole time of flight mass spectrometry (LC-QTOFMS). In our present study, AZA analogues in seven strains of A. poporum from Japanese coastal waters (including two previously reported strains) were determined by these detection techniques. The dominant AZA in the seven strains was AZA2 accompanied by small amounts of several known AZAs and twelve new AZA analogues. Eight of the twelve new AZA analogues discovered in our present study were detected as bi-charged ions on the positive mode LC/MS/MS. This is the first report describing AZA analogues detected as bi-charged ions with hexose and sulfate groups in their structures.

Transcriptome analysis of the harmful alga Heterosigma akashiwo under a 24-hour light-dark cycle.

The photoperiod, which is defined as the period of time within a 24-hour time frame that light is available, is an important environmental regulator of several physiological processes in phytoplankton, including harmful bloom-forming phytoplankton. The ichthyotoxic raphidophyte Heterosigma akashiwo is a globally distributed bloom-forming phytoplankton. Despite extensive studies on the ecological impact of H. akashiwo, the influence of the photoperiod on crucial biological processes of this species remains unclear. In this study, gene expression in H. akashiwo was analyzed over a 24-hour light-dark (14:10) treatment period. Approximately 36 % of unigenes in H. akashiwo were differentially expressed during this 24-hour treatment period, which is indicative of their involvement in the response to light-dark variation. Notably, the number of differentially expressed genes exhibited an initial increase followed by a subsequent decrease as the sampling time progressed (T0 vs. other time points). Unigenes associated with photosynthesis and photoprotection reached their peak expression levels after 2-4 h of illumination (T12-T14). In contrast, the expression of unigenes associated with DNA replication peaked at the starting point of the dark period (T0). Furthermore, although several unigenes annotated to photoreceptors displayed potential diel periodicity, genes from various photoreceptor families (such as phytochrome and cryptochrome) showed unique expression patterns. Collectively, our findings offer novel perspectives on the response of H. akashiwo to the light-dark cycle, serving as a valuable resource for investigating the physiology and ecology of this species.

Physical drivers of Noctiluca scintillans (Dinophyceae) blooms outbreak in the northern Taiwan Strait: A numerical study.

The red Noctiluca scintillans (RNS) blooms often break out near Pingtan Island, in the northern Taiwan Strait from April to June. It is essential to gain insights into their formation mechanism to predict and provide early warnings for these blooms. Previous studies and observations showed that RNS blooms are the most likely to occur when winds are weak and shifting in direction. To explore this phenomenon further, we employed a high-resolution coastal model to investigate the hydrodynamics influencing RNS blooms around Pingtan Island from April to June 2022. The model results revealed that seawater exhibited weak circulation but strong stratification during RNS blooms. Residence time were examined through numerical experiments by releasing passive neutrally buoyant particles in three bays of Pingtan Island. The results showed a significantly longer residence time during RNS blooms, indicating reduced flushing capabilities within the bays, which could give RNS a stable environment to multiply and aggregate. This hydrodynamic condition provided a favorable basis for RNS blooms breakout near Pingtan Island. The shifts and weakening of the prevailing northeast wind contributed substantially to weakening the flow field around Pingtan Island and played a crucial role in creating the hydrodynamics conducive to RNS blooms. Our study offers fresh insights into the mechanisms underpinning RNS blooms formation near Pingtan Island, providing a vital framework for forecasting RNS blooms in this region.

Toxins and Biliary Atresia: Is Karenia Brevis (Red Tide) The Culprit?

OBJECTIVE: The study objective was to evaluate the association between Karenia brevis (K. brevis) exposure during pregnancy and the prevalence of biliary atresia (BA) in offspring. STUDY DESIGN: This was a hospital-based, case-control study in which cases were infants diagnosed with BA at Johns Hopkins All Children's Hospital from October 2001 to December 2019. Cases were matched 1:4 by age to controls who were randomly selected from a pool of healthy infants hospitalized during the study period for common pediatric diagnoses. Infants were excluded if they had congenital anomalies and/or were non-Florida residents. Gestational K. brevis exposure levels (cells/liter) were determined from Florida Fish and Wildlife Conservation Commission exposure data at 10- and 50 mile radii from the mother's zip code of residence. Multivariable conditional logistic regression determined odds of BA in offspring in relation to maternal gestational K. brevis exposure adjusted for infant sex, race/ethnicity, coastal residence, and seasonality. RESULTS: Of 38 cases and 152 controls, no significant inter-group differences were observed for infant race/ethnicity, season of birth, or coastal residence. Median gestational exposure at the 10 mile radius was 0 cells/liter in both groups. A greater proportion of cases had no gestational K. brevis exposure (63.2 %, n = 24) in comparison to controls (37.5 %, n = 57; p = .04) at a 10 mile radius. At a 50 mile radius, cases had a peak median exposure at 6 months of gestation compared to controls' peak at 9 months. After adjustment for sex, seasonality, race/ethnicity, and coastal residence, there was no significant association between BA and maximum K. brevis exposure per trimester of pregnancy observed at a 10- or 50 mile radius. CONCLUSION: In this matched case-control study, we observed no association between gestational K. brevis (cells/liter) exposure at a 10- or 50 mile radius from maternal zip code of residence and BA in offspring.

Response of the toxic dinoflagellate Alexandrium minutum to exudates of the eelgrass Zostera marina.

Biotic interactions are a key factor in the development of harmful algal blooms. Recently, a lower abundance of planktonic dinoflagellates has been reported in areas dominated by seagrass beds, suggesting a negative interaction between both groups of organisms. The interaction between planktonic dinoflagellates and marine phanerogams, as well as the way in which bacteria can affect this interaction, was studied in two experiments using a non-axenic culture of the toxic dinoflagellate Alexandrium minutum exposed to increasing additions of eelgrass (Zostera marina) exudates from old and young leaves and to the presence or absence of antibiotics. In these experiments, A. minutum abundance, growth rate and photosynthetic efficiency (Fv/Fm), as well as bacterial abundance, were measured every 48 h. Toxin concentration per cell was determined at the end of both experiments. Our results demonstrated that Z. marina exudates reduced A. minutum growth rate and, in one of the experiments, also the photosynthetic efficiency. These results are not an indirect effect mediated by the bacteria in the culture, although their growth modify the magnitude of the negative impact on the dinoflagellate growth rate. No clear pattern was observed in the variation of toxin production with the treatments.

Sources and profiles of toxins in shellfish from the south-central coast of Chile (36°â€’ 43° S).

The study of marine toxins in shellfish is of the utmost importance to ensure people's food safety. Marine toxins in shellfish and microalgae in the water column off the south-central coast of Chile (36°â€’43° S) were studied in a network of 64 stations over a 14-month period. The relative abundance of harmful species Alexandrium catenella, Alexandrium ostenfeldii, Protoceratium reticulatum, Dinophysis acuminata, Dinophysis acuta, Pseudo-nitzschia seriata group and P. delicatissima group was analyzed. The detection and quantification of lipophilic toxins and domoic acid (DA) in shellfish was determined by UHPLC-MS/MS, and for Paralytic Shellfish Toxins (PSTs) by HPLC-FD with post-column oxidation, while for a culture of A. ostenfeldii a Hylic-UHPLC-MS/MS was used. Results showed that DA, gonyautoxin (GTX)-2, GTX-3 and pectenotoxin (PTX)-2 were detected below the permitted limits, while Gymnodimine (GYM)-A and 13-desmethylespirolide C (SPX-1) were below the limit of quantitation. According to the distribution and abundance record of microalgae, DA would be associated to P. seriata and P. delicatissima-groups, PTX-2 to D. acuminata, and GTX-2, GTX-3, GYM-A, and SPX-1 to A. ostenfeldii. However, the toxin analysis of an A. ostenfeldii culture from the Biobío region only showed the presence of the paralytic toxins C2, GTX-2, GTX-3, GTX-5 and saxitoxin, therefore, the source of production of GYM and SPX is still undetermined.

eDNA metabarcoding reveals biodiversity and depth stratification patterns of dinoflagellate assemblages within the epipelagic zone of the western Coral Sea.

BACKGROUND: Dinoflagellates play critical roles in the functioning of marine ecosystems but also may pose a hazard to human and ecosystem health by causing harmful algal blooms (HABs). The Coral Sea is a biodiversity hotspot, but its dinoflagellate assemblages in pelagic waters have not been studied by modern sequencing methods. We used metabarcoding of the 18 S rRNA V4 amplicon to assess the diversity and structure of dinoflagellate assemblages throughout the water column to a depth of 150 m at three stations in the Western Coral Sea. Additionally, at one station we compared metabarcoding with morphological methods to optimise identification and detection of dinoflagellates. RESULTS: Stratification of dinoflagellate assemblages was evident in depth-specific relative abundances of taxonomic groups; the greatest difference was between the 5-30 m assemblages and the 130-150 m assemblages. The relative abundance of Dinophyceae (photosynthetic and heterotrophic) decreased with increasing depth, whereas that of Syndiniales (parasitic) increased with increasing depth. The composition of major taxonomic groups was similar among stations. Taxonomic richness and diversity of amplicon sequence variants (ASVs) were similar among depths and stations; however, the abundance of dominant taxa was highest within 0-30 m, and the abundance of rare taxa was highest within 130-150 m, indicating adaptations to specific depth strata. The number of unclassified ASVs at the family and species levels was very high, particularly for Syndinian representatives. CONCLUSIONS: Dinoflagellate assemblages in open water of the Coral Sea are highly diverse and taxonomically stratified by depth; patterns of relative abundance along the depth gradient reflect environmental factors and ecological processes. Metabarcoding detects more species richness than does traditional microscopical methods of sample analysis, yet the methods are complementary, with morphological analysis revealing additional richness. The large number of unclassified dinoflagellate-ASVs indicates a need for improved taxonomic reference databases and suggests presence of dinoflagellate-crypto and-morphospecies.

Targeted Metabolite Fingerprints of Thirteen Gambierdiscus, Five Coolia and Two Fukuyoa Species.

The genus Gambierdiscus produces an array of bioactive hydrophilic and lipophilic secondary metabolites that range in mode of action and toxicity. In this study, the metabolite fingerprint was mapped for thirteen Gambierdiscus, five Coolia and two Fukuyoa species (34 isolates) by assessing the production of 56 characterised secondary metabolites. Gambierdiscus polynesiensis was the only species to produce Pacific-ciguatoxin-3B (P-CTX3B), P-CTX3C, iso-P-CTX3B/C, P-CTX4A, P-CTX4B and iso-P-CTX4A/B. G. australes produced maitotoxin-1 (MTX-1) and MTX-5, G. cheloniae produced MTX-6 and G. honu produced MTX-7. Ubiquitous production of 44-methylgambierone was observed amongst all the Gambierdiscus isolates, with nine species also producing gambierone. Additional gambierone analogues, including anhydrogambierone (tentatively described herein), were also detected in all Gambierdiscus species, two Coolia and two Fukuyoa species. Gambieroxide was detected in G. lewisii and G. pacificus and gambieric acid A was detected in ten Gambierdiscus species, with G. australes (CAWD381) being the only isolate to produce gambieric acids A-D. This study has demonstrated that the isolates tested to date produce the known CTXs or MTXs, but not both, and highlighted several species that produced 'unknown' compounds displaying characteristics of cyclic polyethers, which will be the focus of future compound discovery efforts.

First Report of Pinnatoxin-G (PnTX-G) in a Marine-Coastal Area of the Adriatic Sea Associated with the Presence of the Dinoflagellate Vulcanodinium rugosum.

This study reports the first detection of the marine neurotoxin pinnatoxin-G (PnTX-G) in clams collected in the northwestern Adriatic Sea (Italy). It also represents the first report of the potential toxin-producing dinoflagellate, Vulcanodinium rugosum, in Italian seas. This result, from the coasts of the Emilia-Romagna Region, indicates a successful colonization process, reflecting conditions in France where V. rugosum was initially documented. In this case, the concentration of PnTXs was very low, making further sampling necessary to fully understand the extent of the phenomenon. Discussions on the need to obtain more data to support a proper risk assessment and the need to implement a monitoring program that includes emerging marine biotoxins are also included.