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The ISME Journal Jan 2024Dinoflagellates in the family Symbiodiniaceae are taxonomically diverse, predominantly symbiotic lineages that are well-known for their association with corals. The...
Dinoflagellates in the family Symbiodiniaceae are taxonomically diverse, predominantly symbiotic lineages that are well-known for their association with corals. The ancestor of these taxa is believed to have been free-living. The establishment of symbiosis (i.e. symbiogenesis) is hypothesized to have occurred multiple times during Symbiodiniaceae evolution, but its impact on genome evolution of these taxa is largely unknown. Among Symbiodiniaceae, the genus Effrenium is a free-living lineage that is phylogenetically positioned between two robustly supported groups of genera within which symbiotic taxa have emerged. The apparent lack of symbiogenesis in Effrenium suggests that the ancestral features of Symbiodiniaceae may have been retained in this lineage. Here, we present de novo assembled genomes (1.2-1.9 Gbp in size) and transcriptome data from three isolates of Effrenium voratum and conduct a comparative analysis that includes 16 Symbiodiniaceae taxa and the other dinoflagellates. Surprisingly, we find that genome reduction, which is often associated with a symbiotic lifestyle, predates the origin of Symbiodiniaceae. The free-living lifestyle distinguishes Effrenium from symbiotic Symbiodiniaceae vis-à-vis their longer introns, more-extensive mRNA editing, fewer (~30%) lineage-specific gene sets, and lower (~10%) level of pseudogenization. These results demonstrate how genome reduction and the adaptation to distinct lifestyles intersect to drive diversification and genome evolution of Symbiodiniaceae.
Topics: Dinoflagellida; Symbiosis; Phylogeny; Evolution, Molecular; Transcriptome; Genome, Protozoan
PubMed: 38655774
DOI: 10.1093/ismejo/wrae059 -
Nature Communications Apr 2024Dinoflagellates are ecologically important and essential to corals and other cnidarians as phytosymbionts, but their photosystems had been underexplored. Recently,...
Dinoflagellates are ecologically important and essential to corals and other cnidarians as phytosymbionts, but their photosystems had been underexplored. Recently, photosystem I (PSI) of dinoflagellate sp. was structurally characterized using cryo-Electron Microscopy (cryo-EM). These analyses revealed a distinct organization of the PSI supercomplex, including two previously unidentified subunits, PsaT and PsaU, and shed light on interactions between light harvesting antenna proteins and the PSI core. These results have implications with respect to the evolution of dinoflagellates and their association with cnidarians.
Topics: Photosystem I Protein Complex; Photosynthesis; Chlorophyll; Dinoflagellida; Photosystem II Protein Complex; Light; Light-Harvesting Protein Complexes
PubMed: 38637576
DOI: 10.1038/s41467-024-47797-1 -
Environmental Research Jul 2024Paralytic shellfish toxins (PST) in shellfish products have led to severe risks to human health. To monitor the risk, the Canadian Shellfish Sanitation Program has been...
Paralytic shellfish toxins (PST) in shellfish products have led to severe risks to human health. To monitor the risk, the Canadian Shellfish Sanitation Program has been collecting longitudinal PST measurements in blue mussel (Mytilus edulis) and soft-shell clam (Mya arenaria) samples in six coastal provinces of Canada. The spatial distributions of major temporal variation patterns were studied via Functional Principal Component Analysis. Seasonal increases in PST contamination were found to vary the most in terms of magnitude along the coastlines, which provides support for location-specific management of the time-sensitive PST contamination. In British Columbia, the first functional principal component (FPC1) indicated the variance among the magnitudes, while FPC2 indicated the seasonality of the PST levels. The temporal variations tended to be positively correlated with the abundance of dianoflagellates Alexandrium spp., and negatively with precipitation and inorganic nutrients. These findings indicate the underlying mechanism of PST variation in various geographical settings. In New Brunswick, Prince Edward, and Nova Scotia, the top FPCs indicated that the PST contamination differed mostly in the seasonal increase of the PST level during summer.
Topics: Animals; Longitudinal Studies; Marine Toxins; Canada; Seasons; Environmental Monitoring; Mytilus edulis; Bivalvia; Principal Component Analysis; Dinoflagellida; Shellfish Poisoning
PubMed: 38636647
DOI: 10.1016/j.envres.2024.118944 -
Journal of Hazardous Materials Jun 2024The presence in marine shellfish of toxins and pollutants like rare earth elements (REEs) poses a major threat to human well-being, coastal ecosystems, and marine life....
Can exposure to Gymnodinium catenatum toxic blooms influence the impacts induced by Neodymium in Mytilus galloprovincialis mussels? What doesn't kill can make them stronger?
The presence in marine shellfish of toxins and pollutants like rare earth elements (REEs) poses a major threat to human well-being, coastal ecosystems, and marine life. Among the REEs, neodymium (Nd) stands out as a widely utilized element and is projected to be among the top five critical elements by 2025. Gymnodinum catenatum is a phytoplankton species commonly associated with the contamination of bivalves with paralytic shellfish toxins. This study evaluated the biological effects of Nd on the mussel species Mytilus galloprovincialis when exposed to G. catenatum cells for fourteen days, followed by a recovery period in uncontaminated seawater for another fourteen days. After co-exposure, mussels showed similar toxin accumulation in the Nd and G. catenatum treatment in comparison with the G. catenatum treatment alone. Increased metabolism and enzymatic defenses were observed in organisms exposed to G. catenatum cells, while Nd inhibited enzyme activity and caused cellular damage. Overall, this study revealed that the combined presence of G. catenatum cells and Nd, produced positive synergistic effects on M. galloprovincialis biochemical responses compared to G. catenatum alone, indicating that organisms' performance may be significantly modulated by the presence of multiple co-occurring stressors, such those related to chemical pollution and harmful algal blooms. ENVIRONMENTAL IMPLICATIONS: Neodymium (Nd) is widely used in green technologies like wind turbines, and this element's potential threats to aquatic environments are almost unknown, especially when co-occurring with other environmental factors such as blooms of toxic algae. This study revealed the cellular impacts induced by Nd in the bioindicator species Mytilus galloprovincialis but further demonstrated that the combination of both stressors can generate a positive defense response in mussels. The present findings also demonstrated that the impacts caused by Nd lasted even after a recovery period while a previous exposure to the toxins generated a faster biochemical improvement by the mussels.
Topics: Animals; Mytilus; Neodymium; Dinoflagellida; Marine Toxins; Harmful Algal Bloom; Water Pollutants, Chemical
PubMed: 38636232
DOI: 10.1016/j.jhazmat.2024.134220 -
Phytochemistry Jun 2024Dinoflagellates of the genus Gambierdiscus have been associated with ciguatera, the most common non-bacterial fish-related intoxication in the world. Many studies report... (Review)
Review
Dinoflagellates of the genus Gambierdiscus have been associated with ciguatera, the most common non-bacterial fish-related intoxication in the world. Many studies report the presence of potentially toxic Gambierdiscus species along the Atlantic coasts including G. australes, G. silvae and G. excentricus. Estimates of their toxicity, as determined by bio-assays, vary substantially, both between species and strains of the same species. Therefore, there is a need for additional knowledge on the metabolite production of Gambierdiscus species and their variation to better understand species differences. Using liquid chromatography coupled to mass spectrometry, toxin and metabolomic profiles of five species of Gambierdiscus found in the Atlantic Ocean were reported. In addition, a molecular network was constructed aiming at annotating the metabolomes. Results demonstrated that G. excentricus could be discriminated from the other species based solely on the presence of MTX4 and sulfo-gambierones and that the variation in toxin content for a single strain could be up to a factor of two due to different culture conditions between laboratories. While untargeted analyses highlighted a higher variability at the metabolome level, signal correction was applied and supervised multivariate statistics performed on the untargeted data set permitted the selection of 567 features potentially useful as biomarkers for the distinction of G. excentricus, G. caribaeus, G. carolinianus, G. silvae and G. belizeanus. Further studies will be required to validate the use of these biomarkers in discriminating Gambierdiscus species. The study also provided an overview about 17 compound classes present in Gambierdiscus, however, significant improvements in annotation are still required to reach a more comprehensive knowledge of Gambierdiscus' metabolome.
Topics: Atlantic Ocean; Dinoflagellida; Mass Spectrometry; Chromatography, Liquid; Metabolomics
PubMed: 38631521
DOI: 10.1016/j.phytochem.2024.114095 -
FEMS Microbiology Ecology Apr 2024The hydrographic variability in the fjords of Svalbard significantly influences water mass properties, causing distinct patterns of microbial diversity and community...
The hydrographic variability in the fjords of Svalbard significantly influences water mass properties, causing distinct patterns of microbial diversity and community composition between surface and subsurface layers. However, surveys on the phytoplankton-associated bacterial communities, pivotal to ecosystem functioning in Arctic fjords, are limited. This study investigated the interactions between phytoplankton and heterotrophic bacterial communities in Svalbard fjord waters through comprehensive eDNA metabarcoding with 16S and 18S rRNA genes. The 16S rRNA sequencing results revealed a homogenous community composition including a few dominant heterotrophic bacteria across fjord waters, whereas 18S rRNA results suggested a spatially diverse eukaryotic plankton distribution. The relative abundances of heterotrophic bacteria showed a depth-wise distribution. By contrast, the dominant phytoplankton populations exhibited variable distributions in surface waters. In the network model, the linkage of phytoplankton (Prasinophytae and Dinophyceae) to heterotrophic bacteria, particularly Actinobacteria, suggested the direct or indirect influence of bacterial contributions on the fate of phytoplankton-derived organic matter. Our prediction of the metabolic pathways for bacterial activity related to phytoplankton-derived organic matter suggested competitive advantages and symbiotic relationships between phytoplankton and heterotrophic bacteria. Our findings provide valuable insights into the response of phytoplankton-bacterial interactions to environmental changes in Arctic fjords.
Topics: Phytoplankton; Arctic Regions; Bacteria; RNA, Ribosomal, 16S; Heterotrophic Processes; Seasons; RNA, Ribosomal, 18S; DNA Barcoding, Taxonomic; Estuaries; Svalbard; Ice Cover; Ecosystem; DNA, Bacterial; Biodiversity; Microbiota
PubMed: 38621717
DOI: 10.1093/femsec/fiae059 -
The Science of the Total Environment Jun 2024The Reloncaví estuary in southern Chile is famous for its aquaculture. However, recurring harmful algal blooms have adversely affected mussel production. Therefore,...
The Reloncaví estuary in southern Chile is famous for its aquaculture. However, recurring harmful algal blooms have adversely affected mussel production. Therefore, regular monitoring of algal toxins is urgently needed to better understand the contamination status of the estuary. In this study, we quantified 15 types of lipophilic shellfish toxins in Metri Bay in the Reloncaví estuary on a biweekly basis for 4 years. We identified algal species using microscopy and metabarcoding analysis. We also measured water temperature, salinity, chlorophyll-a, and dissolved oxygen to determine the potential relationships of these parameters with algal toxin production. Our results revealed the presence of a trace amount of pectenotoxin and the causal phytoplankton Dinophysis, as well as yessotoxin and the causal phytoplankton Protoceratium. Statistical analysis indicated that fluctuations in water temperature affected the detection of these toxins. Additionally, metabarcoding analysis detected the highly toxic phytoplankton Alexandrium spp. in some samples. Although our results suggest that the level of lipophilic shellfish toxins in Metri Bay during the study period was insignificantly low using our current LC-MS method, the confirmed presence of highly toxic algae in Metri Bay raises concerns, given that favorable environmental conditions could cause blooms.
Topics: Harmful Algal Bloom; Chile; Estuaries; Environmental Monitoring; Marine Toxins; Phytoplankton; Animals; Dinoflagellida
PubMed: 38615760
DOI: 10.1016/j.scitotenv.2024.172374 -
Scientific Reports Apr 2024The 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...
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, NO, and pH, changes in these environmental factors would lead to changes in the algal community structure, thus affecting the stability of the network structure.
Topics: Lakes; Phytoplankton; Salinity; Diatoms; Chlorophyta; China; Dinoflagellida
PubMed: 38594439
DOI: 10.1038/s41598-024-58636-0 -
Microbiology Spectrum May 2024Species delimitation based on lineage definition has become increasingly popular. However, these methods have been limited, especially for species that lack genomic data...
Species delimitation based on lineage definition has become increasingly popular. However, these methods have been limited, especially for species that lack genomic data and are morphologically similar. The trickiest part for the species identification is that the interspecific and intraspecific boundaries are vague. Taking (Dinophyta) as an example, analysis of cell morphology, growth, and toxin synthesis in both species of and does not provide a reliable basis for species delineation. However, through phylogenetic and genetic distance analyses of their ITS and LSU sequences, establishment of evolutionary tree based on orthologous gene sequences, and combining the results of automatic barcode gap discovery and Poisson tree processes models, it was sustained that does not belong to the complex and should be considered as an independent species. Interspecies genetic evolution analysis revealed that and may contribute to evolutionary direction that favors combating reverse environmental factors. In , viral invasion may be one of the reasons for its large genome size. In the study, complex has been selected as an example to enhance the taxonomic identification of microalgae through molecular and genetic evolution, offering valuable insights into refining taxonomic identification and promoting microbial biodiversity research in other species.IMPORTANCEMicroalgae, especially the species known as , have received significant attention due to their ability to trigger harmful algal blooms and produce toxins. However, the boundaries between species and within species are ambiguous. Clear and comprehensive species delineation indicates that should be considered as an independent species, separate from the complex. Improving the classification and identification of microalgae through molecular and genetic evolution will provide reference points for other cryptic species. occupy multiple ecological niches in marine environments, and studying their evolutionary direction contributes to understanding their ecological adaptations and community succession.
Topics: Phylogeny; Microalgae; Dinoflagellida; Evolution, Molecular; DNA Barcoding, Taxonomic
PubMed: 38572997
DOI: 10.1128/spectrum.02367-23 -
Sensors (Basel, Switzerland) Mar 2024Bioluminescence is light produced by organisms through chemical reactions. In most cases, bioluminescent organisms produce light in response to mechanical stimulation,...
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.
Topics: Animals; Dinoflagellida; Phytoplankton; Computer Simulation; Plankton; Zooplankton
PubMed: 38544222
DOI: 10.3390/s24061958