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PloS One 2020Representatives of the marine dinophyte family Amphidomataceae produce lipophilic phycotoxins called azaspiracids (AZA) which may cause azaspiracid shellfish poisoning...
Representatives of the marine dinophyte family Amphidomataceae produce lipophilic phycotoxins called azaspiracids (AZA) which may cause azaspiracid shellfish poisoning (AZP) in humans after consumption of contaminated seafood. Three of the four known toxigenic species are observed frequently in the eastern North Atlantic. In 2018, a research survey was performed to strengthen knowledge on the distribution and abundance of toxigenic Amphidomataceae and their respective toxins in Irish coastal waters and in the North Sea. Species-specific quantification of the three toxigenic species (Azadinium spinosum, Azadinium poporum and Amphidoma languida) was based on recently developed qPCR assays, whose performance was successfully validated and tested with specificity tests and spike experiments. The multi-method approach of on-board live microscopy, qPCR assays and chemical AZA-analysis revealed the presence of Amphidomataceae in the North Atlantic including the three targeted toxigenic species and their respective AZA analogues (AZA-1, -2, -33, -38, -39). Azadinium spinosum was detected at the majority of Irish stations with a peak density of 8.3 x 104 cells L-1 and AZA (AZA-1, -2, -33) abundances up to 1,274 pg L-1. Amphidoma languida was also present at most Irish stations but appeared in highest abundance in a bloom at a central North Sea station with a density of 1.2 x 105 cells L-1 and an AZA (AZA-38, -39) abundances of 618 pg L-1. Azadinium poporum was detected sporadically at the Irish south coast and North Sea and was rather low in abundance during this study. The results confirmed the wide distribution and frequent occurrence of the target species in the North Atlantic area and revealed, for the first time, bloom abundances of toxigenic Amphidomataceae in this area. This emphasizes the importance of future studies and monitoring of amphidomatacean species and their respective AZA analogues in the North Atlantic.
Topics: Biomass; Dinoflagellida; Marine Toxins; North Sea; Seawater; Spiro Compounds
PubMed: 32559229
DOI: 10.1371/journal.pone.0235015 -
Marine Drugs Jul 2022Blooms of the benthic toxic dinoflagellate genus have been recorded more frequently during the last two decades, particularly in warm temperate areas such as the...
Blooms of the benthic toxic dinoflagellate genus have been recorded more frequently during the last two decades, particularly in warm temperate areas such as the Mediterranean Sea. The proliferation of species may cause deleterious effects on ecosystems and can impact human health through skin contact or aerosol inhalation. In the eastern Atlantic Ocean, the toxic cf. has not yet been reported to the north of Portugal, and the only species present further north was cf. , for which the toxic risk is considered low. During summer blooms of unidentified species on the French Basque coast (Atlantic) in 2020 and 2021, people suffered from irritations and respiratory disorders, and the number of analyzed cases reached 674 in 2021. In order to investigate the causes, sampling was carried out during summer 2021 to (i) taxonomically identify species present using a molecular approach, (ii) isolate strains from the bloom and culture them, and (iii) characterize the presence of known toxins which may be involved. For the first time, this study reports the presence of both cf. and cf. , for which the French Basque coast is a new upper distribution limit. Furthermore, the presence of ovatoxins a, b, c, and d in the environmental sample and in a cultivated strain in culture confirmed the toxic nature of the bloom and allowed identifying cf. as the producer. The present data identify a new health risk in the area and highlight the extended distribution of some harmful dinoflagellates, presumably in relation to climate change.
Topics: Atlantic Ocean; Dinoflagellida; Ecosystem; Humans; Mediterranean Sea; Portugal
PubMed: 35877754
DOI: 10.3390/md20070461 -
The ISME Journal Nov 2019Coral reefs are threatened by global warming, which disrupts the symbiosis between corals and their photosynthetic symbionts (Symbiodiniaceae), leading to mass coral...
Coral reefs are threatened by global warming, which disrupts the symbiosis between corals and their photosynthetic symbionts (Symbiodiniaceae), leading to mass coral bleaching. Planktonic diazotrophs or dinitrogen (N)-fixing prokaryotes are abundant in coral lagoon waters and could be an alternative nutrient source for corals. Here we incubated untreated and bleached coral colonies of Stylophora pistillata with a N-pre-labelled natural plankton assemblage containing diazotrophs. N assimilation rates in Symbiodiniaceae cells and tissues of bleached corals were 5- and 30-fold higher, respectively, than those measured in untreated corals, demonstrating that corals incorporate more nitrogen derived from planktonic diazotrophs under bleaching conditions. Bleached corals also preferentially fed on Synechococcus, nitrogen-rich picophytoplanktonic cells, instead of Prochlorococcus and picoeukaryotes, which have a lower cellular nitrogen content. By providing an alternative source of bioavailable nitrogen, both the incorporation of nitrogen derived from planktonic diazotrophs and the ingestion of Synechococcus may have profound consequences for coral bleaching recovery, especially for the many coral reef ecosystems characterized by high abundance and activity of planktonic diazotrophs.
Topics: Animals; Anthozoa; Coral Reefs; Dinoflagellida; Ecosystem; Global Warming; Heterotrophic Processes; Photosynthesis; Symbiosis; Synechococcus
PubMed: 31249389
DOI: 10.1038/s41396-019-0456-2 -
The ISME Journal Oct 2023Dinoflagellates of the family Kryptoperidiniaceae, known as "dinotoms", possess diatom-derived endosymbionts and contain individuals at three successive evolutionary...
Dinoflagellates of the family Kryptoperidiniaceae, known as "dinotoms", possess diatom-derived endosymbionts and contain individuals at three successive evolutionary stages: a transiently maintained kleptoplastic stage; a stage containing multiple permanently maintained diatom endosymbionts; and a further permanent stage containing a single diatom endosymbiont. Kleptoplastic dinotoms were discovered only recently, in Durinskia capensis; until now it has not been investigated kleptoplastic behavior and the metabolic and genetic integration of host and prey. Here, we show D. capensis is able to use various diatom species as kleptoplastids and exhibits different photosynthetic capacities depending on the diatom species. This is in contrast with the prey diatoms in their free-living stage, as there are no differences in their photosynthetic capacities. Complete photosynthesis including both the light reactions and the Calvin cycle remain active only when D. capensis feeds on its habitual associate, the "essential" diatom Nitzschia captiva. The organelles of another edible diatom, N. inconspicua, are preserved intact after ingestion by D. capensis and expresses the psbC gene of the photosynthetic light reaction, while RuBisCO gene expression is lost. Our results indicate that edible but non-essential, "supplemental" diatoms are used by D. capensis for producing ATP and NADPH, but not for carbon fixation. D. capensis has established a species-specifically designed metabolic system allowing carbon fixation to be performed only by its essential diatoms. The ability of D. capensis to ingest supplemental diatoms as kleptoplastids may be a flexible ecological strategy, to use these diatoms as "emergency supplies" while no essential diatoms are available.
Topics: Humans; Dinoflagellida; Symbiosis; Photosynthesis; Biological Evolution; Diatoms
PubMed: 37391621
DOI: 10.1038/s41396-023-01464-3 -
Applied and Environmental Microbiology Sep 2021The lipid production potentials of 8 microalgal species were investigated. Among these 8 species, the best strain was a dominant bloom-causing dinoflagellate,...
The lipid production potentials of 8 microalgal species were investigated. Among these 8 species, the best strain was a dominant bloom-causing dinoflagellate, Prorocentrum donghaiense; this species had a lipid content of 49.32% ± 1.99% and exhibited a lipid productivity of 95.47 ± 0.99 mg liter day, which was 2-fold higher than the corresponding values obtained for the oleaginous microalgae Nannochloropsis gaditana and Phaeodactylum tricornutum. which is enriched in C and C, is appropriate for commercial docosahexaenoic acid (DHA) production. Nitrogen or phosphorus stress markedly induced lipid accumulation to levels surpassing 75% of the dry weight, increased the C and C contents, and decreased the C and C contents, and these effects resulted in decreases in the unsaturated fatty acid levels and changes in the lipid properties of such that the species met the biodiesel specification standards. Compared with the results obtained under N-deficient conditions, the enhancement in the activity of alkaline phosphatase of observed under P-deficient conditions partly alleviated the adverse effects on the photosynthetic system exerted by P deficiency to induce the production of more carbohydrates for lipogenesis. The supernatant of the algicidal bacterium sp. strain Y42 culture lysed without decreasing its lipid content, which resulted in facilitation of the downstream oil extraction process and energy savings through the lysis of algal cells. The Y42 supernatant treatment improved the lipid profiles of algal cells by increasing their C, C, and C contents and decreasing their C and C contents, which is favorable for biodiesel production. This study demonstrates the high potential of Prorocentrum donghaiense, a dominant bloom-causing dinoflagellate, for lipid production. Compared with previously studied oleaginous microalgae, exhibit greater potential for practical application due to its higher biomass and lipid contents. Nutrient deficiency and the algicidal bacterium sp. strain Y42 improved the suitability of the lipid profile of for biodiesel production. Furthermore, sp. Y42 effectively lysed algal cells, which facilitates the downstream oil extraction process for biodiesel production and results in energy savings through the lysing of algal cells. This study provides a more promising candidate for the production of docosahexaenoic acid (DHA) for human nutritional products and of microalgal biofuel as well as a more cost-effective method for breaking algal cells. The high lipid productivity of and algal cell lysis by algicidal bacteria contribute to reductions in the production cost of microalgal oil.
Topics: Biofuels; Dinoflagellida; Lipid Metabolism; Lipids; Nutrients; Paracoccus
PubMed: 34319787
DOI: 10.1128/AEM.01159-21 -
PloS One 2021Foraminifera are a group of mostly marine protists with high taxonomic diversity. Species identification is often complex, as both morphological and molecular approaches...
Foraminifera are a group of mostly marine protists with high taxonomic diversity. Species identification is often complex, as both morphological and molecular approaches can be challenging due to a lack of unique characters and reference sequences. An integrative approach combining state of the art morphological and molecular tools is therefore promising. In this study, we analysed large benthic Foraminifera of the genus Amphisorus from Western Australia and Indonesia. Based on previous findings on high morphological variability observed in the Soritidae and the discontinuous distribution of Amphisorus along the coast of western Australia, we expected to find multiple morphologically and genetically unique Amphisorus types. In order to gain detailed insights into the diversity of Amphisorus, we applied micro CT scanning and shotgun metagenomic sequencing. We identified four distinct morphotypes of Amphisorus, two each in Australia and Indonesia, and showed that each morphotype is a distinct genotype. Furthermore, metagenomics revealed the presence of three dinoflagellate symbiont clades. The most common symbiont was Fugacium Fr5, and we could show that its genotypes were mostly specific to Amphisorus morphotypes. Finally, we assembled the microbial taxa associated with the two Western Australian morphotypes, and analysed their microbial community composition. Even though each Amphisorus morphotype harboured distinct bacterial communities, sampling location had a stronger influence on bacterial community composition, and we infer that the prokaryotic community is primarily shaped by the microhabitat rather than host identity. The integrated approach combining analyses of host morphology and genetics, dinoflagellate symbionts, and associated microbes leads to the conclusion that we identified distinct, yet undescribed taxa of Amphisorus. We argue that the combination of morphological and molecular methods provides unprecedented insights into the diversity of foraminifera, which paves the way for a deeper understanding of their biodiversity, and facilitates future taxonomic and ecological work.
Topics: Biodiversity; Dinoflagellida; Foraminifera; Indonesia; Metagenomics; Symbiosis; Western Australia
PubMed: 33395419
DOI: 10.1371/journal.pone.0244616 -
Marine Drugs Nov 2021In recent decades, more than 130 potentially toxic metabolites originating from dinoflagellate species belonging to the genus or metabolized by marine organisms have... (Review)
Review
In recent decades, more than 130 potentially toxic metabolites originating from dinoflagellate species belonging to the genus or metabolized by marine organisms have been described. These metabolites include the well-known and large group of brevetoxins (BTXs), responsible for foodborne neurotoxic shellfish poisoning (NSP) and airborne respiratory symptoms in humans. spp. also produce brevenal, brevisamide and metabolites belonging to the hemi-brevetoxin, brevisin, tamulamide, gymnocin, gymnodimine, brevisulcenal and brevisulcatic acid groups. In this review, we summarize the available knowledge in the literature since 1977 on these various identified metabolites, whether they are produced directly by the producer organisms or biotransformed in marine organisms. Their structures and physicochemical properties are presented and discussed. Among future avenues of research, we highlight the need for more toxin occurrence data with analytical techniques, which can specifically determine the analogs present in samples. New metabolites have yet to be fully described, especially the groups of metabolites discovered in the last two decades (e.g tamulamides). Lastly, this work clarifies the different nomenclatures used in the literature and should help to harmonize practices in the future.
Topics: Animals; Aquatic Organisms; Dinoflagellida; Humans; Marine Toxins; Oxocins; Shellfish; Shellfish Poisoning
PubMed: 34940655
DOI: 10.3390/md19120656 -
Proceedings of the National Academy of... Feb 2019Reef-building corals thrive in nutrient-poor marine environments because of an obligate symbiosis with photosynthetic dinoflagellates of the genus Symbiosis is...
Reef-building corals thrive in nutrient-poor marine environments because of an obligate symbiosis with photosynthetic dinoflagellates of the genus Symbiosis is established in most corals through the uptake of from the environment. Corals are sessile for most of their life history, whereas free-living are motile; hence, a mechanism to attract would greatly increase the probability of encounter between host and symbiont. Here, we examined whether corals can attract free-living motile by their green fluorescence, emitted by the excitation of endogenous GFP by purple-blue light. We found that have positive and negative phototaxis toward weak green and strong purple-blue light, respectively. Under light conditions that cause corals to emit green fluorescence, (e.g., strong blue light), were attracted toward live coral fragments. were also attracted toward an artificial green fluorescence dye with similar excitation and emission spectra to coral-GFP. In the field, more were found in traps painted with a green fluorescence dye than in controls. Our results revealed a biological signaling mechanism between the coral host and its potential symbionts.
Topics: Animals; Anthozoa; Cnidaria; Coral Reefs; Dinoflagellida; Fluorescence; Phylogeny; Symbiosis
PubMed: 30670646
DOI: 10.1073/pnas.1812257116 -
Current Biology : CB Nov 2018The dinoflagellate microalga Symbiodinium sustains coral reefs, one of the most diverse ecosystems of the biosphere, through mutualistic endosymbioses with a wide...
The dinoflagellate microalga Symbiodinium sustains coral reefs, one of the most diverse ecosystems of the biosphere, through mutualistic endosymbioses with a wide diversity of benthic hosts [1]. Despite its ecological and economic importance, the presence of Symbiodinium in open oceanic waters remains unknown, which represents a significant knowledge gap to fully understand the eco-evolutionary trajectory and resilience of endangered Symbiodinium-based symbioses. Here, we document the existence of Symbiodinium (i.e., now the family Symbiodiniaceae [2]) in tropical- and temperate-surface oceans using DNA and RNA metabarcoding of size-fractionated plankton samples collected at 109 stations across the globe. Symbiodinium from clades A and C were, by far, the most prevalent and widely distributed lineages (representing 0.1% of phytoplankton reads), while other lineages (clades B, D, E, F, and G) were present but rare. Concurrent metatranscriptomics analyses using the Tara Oceans gene catalog [3] revealed that Symbiodinium clades A and C were transcriptionally active in the open ocean and expressed core metabolic pathways (e.g., photosynthesis, carbon fixation, glycolysis, and ammonium uptake). Metabarcodes and expressed genes of clades A and C were detected in small and large plankton size fractions, suggesting the existence of a free-living population and a symbiotic lifestyle within planktonic hosts, respectively. However, high-resolution genetic markers and microscopy are required to confirm the life history of oceanic Symbiodinium. Overall, the previously unknown, metabolically active presence of Symbiodinium in oceanic waters opens up new avenues for investigating the potential of this oceanic reservoir to repopulate coral reefs following stress-induced bleaching.
Topics: Animals; Biodiversity; Biological Evolution; Coral Reefs; DNA, Protozoan; Dinoflagellida; Gene Expression Profiling; Genetic Markers; Genetic Variation; Symbiosis
PubMed: 30416058
DOI: 10.1016/j.cub.2018.09.024 -
Journal of Phycology Feb 2022Global warming increases the temperature of the ocean surface, which can disrupt dinoflagellate-coral symbioses and result in coral bleaching. Photosynthetic... (Review)
Review
Gene clusters for biosynthesis of mycosporine-like amino acids in dinoflagellate nuclear genomes: Possible recent horizontal gene transfer between species of Symbiodiniaceae (Dinophyceae).
Global warming increases the temperature of the ocean surface, which can disrupt dinoflagellate-coral symbioses and result in coral bleaching. Photosynthetic dinoflagellates of the family Symbiodiniaceae include bleaching-tolerant and bleaching-sensitive coral symbionts. Therefore, understanding the molecular mechanisms for changing symbiont diversity is potentially useful to assist recovery of coral holobionts (corals and their associated microbes, including multiple species of Symbiodiniaceae), although sexual reproduction has not been observed in the Symbiodiniaceae. Recent molecular phylogenetic analyses estimate that the Symbiodiniaceae appeared 160 million years ago and diversified into 15 groups, five genera of which now have available draft genomes (i.e., Symbiodinium, Durusdinium, Breviolum, Fugacium, and Cladocopium). Comparative genomic analyses have suggested that crown groups have fewer gene families than early-diverging groups, although many genes that were probably acquired via gene duplications and horizontal gene transfers (HGTs) have been found in each decoded genome. Because UV stress is likely a contributor to coral bleaching, and because the highly conserved gene cluster for mycosporine-like amino acid (MAA) biosynthesis has been found in thermal-tolerant symbiont genomes, I reviewed genomic features of the Symbiodiniaceae, focusing on possible acquisition of a biosynthetic gene cluster for MAAs, which absorb UV radiation. On the basis of highly conserved noncoding sequences, I hypothesized that HGTs have occurred among members of the Symbiodiniaceae and have contributed to the diversification of Symbiodiniaceae-host relationships. Finally, I proposed that bleaching tolerance may be strengthened by multiple MAAs from both symbiotic dinoflagellates and corals.
Topics: Amino Acids; Animals; Anthozoa; Coral Reefs; Dinoflagellida; Gene Transfer, Horizontal; Multigene Family; Phylogeny; Symbiosis
PubMed: 34699617
DOI: 10.1111/jpy.13219