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Current Biology : CB Oct 2020LaJeunesse introduces the group of unicellular microalgae referred to as 'zooxanthellae'.
LaJeunesse introduces the group of unicellular microalgae referred to as 'zooxanthellae'.
Topics: Animals; Anthozoa; Dinoflagellida; Symbiosis
PubMed: 33022248
DOI: 10.1016/j.cub.2020.03.058 -
Philosophical Transactions of the Royal... Sep 2020This review explores how microbial symbioses may have influenced and continue to influence the evolution of reef-building corals (Cnidaria; Scleractinia). The coral... (Review)
Review
This review explores how microbial symbioses may have influenced and continue to influence the evolution of reef-building corals (Cnidaria; Scleractinia). The coral holobiont comprises a diverse microbiome including dinoflagellate algae (Dinophyceae; Symbiodiniaceae), bacteria, archaea, fungi and viruses, but here we focus on the Symbiodiniaceae as knowledge of the impact of other microbial symbionts on coral evolution is scant. Symbiosis with Symbiodiniaceae has extended the coral's metabolic capacity through metabolic handoffs and horizontal gene transfer (HGT) and has contributed to the ecological success of these iconic organisms. It necessitated the prior existence or the evolution of a series of adaptations of the host to attract and select the right symbionts, to provide them with a suitable environment and to remove disfunctional symbionts. Signatures of microbial symbiosis in the coral genome include HGT from Symbiodiniaceae and bacteria, gene family expansions, and a broad repertoire of oxidative stress response and innate immunity genes. Symbiosis with Symbiodiniaceae has permitted corals to occupy oligotrophic waters as the algae provide most corals with the majority of their nutrition. However, the coral-Symbiodiniaceae symbiosis is sensitive to climate warming, which disrupts this intimate relationship, causing coral bleaching, mortality and a worldwide decline of coral reefs. This article is part of the theme issue 'The role of the microbiome in host evolution'.
Topics: Animals; Anthozoa; Biological Evolution; Dinoflagellida; Global Warming; Microbiota; Symbiosis
PubMed: 32772672
DOI: 10.1098/rstb.2019.0591 -
Trends in Microbiology Aug 2019Coral reefs rely upon the highly optimized coral-Symbiodiniaceae symbiosis, making them sensitive to environmental change and susceptible to anthropogenic stress. Coral... (Review)
Review
Coral reefs rely upon the highly optimized coral-Symbiodiniaceae symbiosis, making them sensitive to environmental change and susceptible to anthropogenic stress. Coral bleaching is predominantly attributed to photo-oxidative stress, yet nutrient availability and metabolism underpin the stability of symbioses. Recent studies link symbiont proliferation under nutrient enrichment to bleaching; however, the interactions between nutrients and symbiotic stability are nuanced. Here, we demonstrate how bleaching is regulated by the forms and ratios of available nutrients and their impacts on autotrophic carbon metabolism, rather than algal symbiont growth. By extension, historical nutrient conditions mediate host-symbiont compatibility and bleaching tolerance over proximate and evolutionary timescales. Renewed investigations into the coral nutrient metabolism will be required to truly elucidate the cellular mechanisms leading to coral bleaching.
Topics: Animals; Anthozoa; Carbon; Dinoflagellida; Microbiota; Nutrients; Phosphorus; Symbiosis; Thermotolerance
PubMed: 30987816
DOI: 10.1016/j.tim.2019.03.004 -
Current Biology : CB Jan 2008
Topics: Animals; Anthozoa; Biodiversity; Conservation of Natural Resources; Dinoflagellida; Food Chain; Greenhouse Effect; Symbiosis
PubMed: 18177705
DOI: 10.1016/j.cub.2007.11.018 -
International Microbiology : the... Dec 2015As early as 1925, the great protozoologist Edouard Chatton classified microorganisms into two categories, the prokaryotic and the eukaryotic microbes, based on light... (Review)
Review
As early as 1925, the great protozoologist Edouard Chatton classified microorganisms into two categories, the prokaryotic and the eukaryotic microbes, based on light microscopical observation of their nuclear organization. Now, by means of transmission electron microscopy, we know that prokaryotic microbes are characterized by the absence of nuclear envelope surrounding the bacterial chromosome, which is more or less condensed and whose chromatin is deprived of histone proteins but presents specific basic proteins. Eukaryotic microbes, the protists, have nuclei surrounded by a nuclear envelope and have chromosomes more or less condensed, with chromatin-containing histone proteins organized into nucleosomes. The extraordinary diversity of mitotic systems presented by the 36 phyla of protists (according to Margulis et al., Handbook of Protoctista, 1990) is in contrast to the relative homogeneity of their chromosome structure and chromatin components. Dinoflagellates are the exception to this pattern. The phylum is composed of around 2000 species, and characterized by unique features including their nucleus (dinokaryon), dinomitosis, chromosome organization and chromatin composition. Although their DNA synthesis is typically eukaryotic, dinoflagellates are the only eukaryotes in which the chromatin, organized into quasi-permanently condensed chromosomes, is in some species devoid of histones and nucleosomes. In these cases, their chromatin contains specific DNA-binding basic proteins. The permanent compaction of their chromosomes throughout the cell cycle raises the question of the modalities of their division and their transcription. Successful in vitro reconstitution of nucleosomes using dinoflagellate DNA and heterologous corn histones raises questions about dinoflagellate evolution and phylogeny. [Int Microbiol 18(4):209-216 (2015)].
Topics: Animals; Chromosomes; Dinoflagellida; Evolution, Molecular; Humans; Phylogeny; Protozoan Proteins
PubMed: 27611673
DOI: 10.2436/20.1501.01.252 -
Microbiology Spectrum Jun 2022The toxic dinoflagellate is a harmful algal bloom-forming species in coastal areas around the world. It produces ichthyotoxins and hemolytic toxins, with deleterious...
The toxic dinoflagellate is a harmful algal bloom-forming species in coastal areas around the world. It produces ichthyotoxins and hemolytic toxins, with deleterious effects on marine ecosystems. In this study, the bacterium sp. FDHY-MZ2, with high algicidal efficiency against , was isolated from a bloom event. Based on the results, it completely lysed cells within 24 h 0.5% (vol/vol), with the algicidal activity of the supernatant of the bacterium culture. Algal cell wall fragmentation occurred, leading to cell death. There was a marked decline in various photochemical traits. When treated with the supernatant, cellulase, pheophorbide a oxygenase (PAO) and cyclin B genes were significantly increased, suggesting induced cell wall deterioration, chloroplast degradation and cell cycle regulation of cells. In addition, the expression levels of reactive oxygen species (ROS) scavenging gene was significantly inhibited, indicating that the ROS removal system was damaged. The bacterial culture was dried to obtain the spray-dried powder, which showed algicidal activity rates of 92.2 and 100% against a laboratory culture and a field microcosm of sp. bloom within 24 h with the addition of 0.04% mass fraction powder. Our results demonstrate that FDHY-MZ2 is a suitable strain for and sp. blooms management. In addition, this study provides a new strategy for the anthropogenic control of harmful algal bloom-forming species . is a noxious algal bloom-forming species that cause damaging of the aquaculture industry and great financial losses. Bacterium with algicidal activity is an ideal agency to inhibit the growth of harmful algae. In this approach application, the bacterium with high algicidal activity is required and the final management material is ideal for easy-to-use. The algicidal characteristics are also needed to understand the effects of the bacterium for managing strategy exploration. In this study, we isolated a novel algicidal bacterium with extremely high lysis efficiency for . The algicidal characteristics of the bacterium as well as the chemical and molecular response of with the strain challenge were examined. Finally, the algicidal powder was explored for application. The results demonstrate that FDHY-MZ2 is suitable for and sp. blooms controlling, and this study provides a new strategy for algicidal bacterium application.
Topics: Bacteria; Dinoflagellida; Ecosystem; Harmful Algal Bloom; Powders; Reactive Oxygen Species
PubMed: 35616372
DOI: 10.1128/spectrum.00429-22 -
Current Biology : CB May 2020Eyes are not unique to animals. As described by Nilsson and Marshall, prominent eyes, complete with retina and lens, have unexpectedly evolved in single cell...
Eyes are not unique to animals. As described by Nilsson and Marshall, prominent eyes, complete with retina and lens, have unexpectedly evolved in single cell dinoflagellates.
Topics: Animals; Dinoflagellida; Lens, Crystalline
PubMed: 32428481
DOI: 10.1016/j.cub.2020.01.077 -
PloS One 2022Dinoflagellate species are traditionally defined using morphological characters, but molecular evidence accumulated over the past several decades indicates many...
Dinoflagellate species are traditionally defined using morphological characters, but molecular evidence accumulated over the past several decades indicates many morphologically-based descriptions are inaccurate. This recognition led to an increasing reliance on DNA sequence data, particularly rDNA gene segments, in defining species. The validity of this approach assumes the divergence in rDNA or other selected genes parallels speciation events. Another concern is whether single gene rDNA phylogenies by themselves are adequate for delineating species or if multigene phylogenies are required instead. Currently, few studies have directly assessed the relative utility of multigene versus rDNA-based phylogenies for distinguishing species. To address this, the current study examined D1-D3 and ITS/5.8S rDNA gene regions, a multi-gene phylogeny, and morphological characters in Gambierdiscus and other related dinoflagellate genera to determine if they produce congruent phylogenies and identify the same species. Data for the analyses were obtained from previous sequencing efforts and publicly available dinoflagellate transcriptomic libraries as well from the additional nine well-characterized Gambierdiscus species transcriptomic libraries generated in this study. The D1-D3 and ITS/5.8S phylogenies successfully identified the described Gambierdiscus and Alexandrium species. Additionally, the data showed that the D1-D3 and multigene phylogenies were equally capable of identifying the same species. The multigene phylogenies, however, showed different relationships among species and are likely to prove more accurate at determining phylogenetic relationships above the species level. These data indicated that D1-D3 and ITS/5.8S rDNA region phylogenies are generally successful for identifying species of Gambierdiscus, and likely those of other dinoflagellates. To assess how broadly general this finding is likely to be, rDNA molecular phylogenies from over 473 manuscripts representing 232 genera and 863 described species of dinoflagellates were reviewed. Results showed the D1-D3 rDNA and ITS phylogenies in combination are capable of identifying 97% of dinoflagellate species including all the species belonging to the genera Alexandrium, Ostreopsis and Gambierdiscus, although it should be noted that multi-gene phylogenies are preferred for inferring relationships among these species. A protocol is presented for determining when D1-D3, confirmed by ITS/5.8S rDNA sequence data, would take precedence over morphological features when describing new dinoflagellate species. This protocol addresses situations such as: a) when a new species is both morphologically and molecularly distinct from other known species; b) when a new species and closely related species are morphologically indistinguishable, but genetically distinct; and c) how to handle potentially cryptic species and cases where morphotypes are clearly distinct but have the same rDNA sequence. The protocol also addresses other molecular, morphological, and genetic approaches required to resolve species boundaries in the small minority of species where the D1-D3/ITS region phylogenies fail.
Topics: DNA, Protozoan; DNA, Ribosomal; Dinoflagellida; Phylogeny
PubMed: 35213572
DOI: 10.1371/journal.pone.0264143 -
Toxins Jan 2020Recurrent blooms of cf. have been reported in Brazil and the Mediterranean Sea with associated ecological, and in the latter case, health impacts. Molecular data...
Recurrent blooms of cf. have been reported in Brazil and the Mediterranean Sea with associated ecological, and in the latter case, health impacts. Molecular data based on the D1-D3 and D8-D10 regions of the LSU rDNA and ITS loci, and the morphology of . cf. isolates and field populations from locations along the Brazilian tropical and subtropical coastal regions and three oceanic islands are presented. Additional ITS sequences from three single cells from the tropical coast are provided. Toxin profiles and quantities of PLTX and their analogues; OVTXs; contained in cells from two clonal cultures and two field blooms from Rio de Janeiro were investigated. Morphology was examined using both light and epifluorescence microscopy. Morphometric analysis of different strains and field populations from diverse locations were compared. Molecular analysis showed that six of the seven sequences grouped at the large "Atlantic/Mediterranean/Pacific" sub-clade, while one sequence branched in a sister clade with sequences from Madeira Island and Greece. The toxin profile of strains and bloom field samples from Rio de Janeiro were dominated by OVTX-a and -b, with total cell quotas (31.3 and 39.3 pg cell) in the range of that previously reported for strains of . cf. .
Topics: Brazil; Dinoflagellida; Marine Toxins; Phylogeny
PubMed: 31979144
DOI: 10.3390/toxins12020070 -
ELife Jul 2019Coral reefs are some of the most important and ecologically diverse marine environments. At the base of the reef ecosystem are dinoflagellate algae, which live...
Coral reefs are some of the most important and ecologically diverse marine environments. At the base of the reef ecosystem are dinoflagellate algae, which live symbiotically within coral cells. Efforts to understand the relationship between alga and coral have been greatly hampered by the lack of an appropriate dinoflagellate genetic transformation technology. By making use of the plasmid-like fragmented chloroplast genome, we have introduced novel genetic material into the dinoflagellate chloroplast genome. We have shown that the introduced genes are expressed and confer the expected phenotypes. Genetically modified cultures have been grown for 1 year with subculturing, maintaining the introduced genes and phenotypes. This indicates that cells continue to divide after transformation and that the transformation is stable. This is the first report of stable chloroplast transformation in dinoflagellate algae.
Topics: Chloroplasts; Dinoflagellida; Gene Expression; Genetics, Microbial; Genomic Instability; Phenotype; Transformation, Genetic
PubMed: 31317866
DOI: 10.7554/eLife.45292