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This article is from PLoS ONE , volume 8 . Abstract Hematodinium is a parasitic dinoflagellate and emerging pathogen of crustaceans. It preferably manifests in haemolymph of marine decapod crustaceans, killing a large variety of genera with significant impacts on fisheries worldwide. There is, however, evidence that some crustacean stocks harbor high prevalence, low intensity infections that may not result in widespread host mortality and are therefore hard to detect. The most widely used methods for detection of Hematodinium are conventional blood smears and polymerase chain reaction (PCR) against ribosomal RNAs. Blood smears demand a trained investigator, are labor intensive and not readily scalable for high-throughput sampling. PCRs only detect parasite DNA and can also suffer from false negatives and positives. In order to develop alternative detection tools for Hematodinium cells in decapod crustaceans we employed an immunological approach against a newly identified, abundant dinoflagellate-specific nuclear protein—Dinoflagellate/Viral NucleoProtein (DVNP). Both immunofluorescence assay (IFA) and Western blot methods against DVNP showed high sensitivity of detection. The Western blot detects Hematodinium parasites to levels of 25 parasites per milliliter of crustacean haemolymph, with the potential for sample pooling and screening of large samples. Using both PCR and these new tools, we have identified Hematodinium cells present in three new host crab taxa, at high prevalence but with no sign of pathogenesis. This extends the known range of Hematodinium to southern Australia.

The Navy has developed a rapid bioassay system (QwikLite) that is proving to be a valuable asset for conducting bioassays on other test media (e.g., metals, storm drain discharge, ship hull coatings, and marine sediments). The basis of detection is to measure a reduction in light from the bioluminescent dinoflagellate Gonyaulax polyedra following exposure to a toxicant. The toxic response is usually measured within 24 hours from the start of the test and can be conducted for a 4-day acute test or 7-day chronic test. A measurable reduction or inhibition in bioluminescence is an adverse effect. The endpoint used to measure this light reduction is the IC50 (a 50% reduction in light output when compared to control cells).

UUVs surveys showed that bioluminescent dinoflagellates from the northern part of the Monterey Bay, CA were able to avoid advection by southward flowing currents along the entrance to the Bay. We investigate if modeling dinoflagellates' vertical swimming can explain the observed dinoflagellates' ability to avoid advection. Our modeling confirmed that observed bioluminescent dinoflagellates' avoidance of advection can be explained by their vertical swimming ability. In the case of swimming with 20m/day, (which is half of observed maximum swimming velocity) around 40% of dinoflagellates population from the northern part of the Bay were advected along the entrance to the Bay in comparison to the case without swimming. This is in agreement with the ratio of around 45% of observed mean bioluminescence intensity at the entrance to the Bay to the observed mean intensity in the northern part of the Bay.

This article is from Genome Biology and Evolution , volume 4 . Abstract The sister phyla dinoflagellates and apicomplexans inherited a drastically reduced mitochondrial genome (mitochondrial DNA, mtDNA) containing only three protein-coding (cob, cox1, and cox3) genes and two ribosomal RNA (rRNA) genes. In apicomplexans, single copies of these genes are encoded on the smallest known mtDNA chromosome (6 kb). In dinoflagellates, however, the genome has undergone further substantial modifications, including massive genome amplification and recombination resulting in multiple copies of each gene and gene fragments linked in numerous combinations. Furthermore, protein-encoding genes have lost standard stop codons, trans-splicing of messenger RNAs (mRNAs) is required to generate complete cox3 transcripts, and extensive RNA editing recodes most genes. From taxa investigated to date, it is unclear when many of these unusual dinoflagellate mtDNA characters evolved. To address this question, we investigated the mitochondrial genome and transcriptome character states of the deep branching dinoflagellate Hematodinium sp. Genomic data show that like later-branching dinoflagellates Hematodinium sp. also contains an inflated, heavily recombined genome of multicopy genes and gene fragments. Although stop codons are also lacking for cox1 and cob, cox3 still encodes a conventional stop codon. Extensive editing of mRNAs also occurs in Hematodinium sp. The mtDNA of basal dinoflagellate Hematodinium sp. indicates that much of the mtDNA modification in dinoflagellates occurred early in this lineage, including genome amplification and recombination, and decreased use of standard stop codons. Trans-splicing, on the other hand, occurred after Hematodinium sp. diverged. Only RNA editing presents a nonlinear pattern of evolution in dinoflagellates as this process occurs in Hematodinium sp. but is absent in some later-branching taxa indicating that this process was either lost in some lineages or developed more than once during the evolution of the highly unusual dinoflagellate mtDNA.

Oceanic and coastal bioluminescence in surface waters, in many instances, is produced by microscopic dinoflagellates. Their light emission is usually observed at a maximum during the night hours and markedly inhibited during the day. This diel periodicity has never been observed in situ for identified species and never before in heterotrophic Protoperidinium dinoflagellates. Pronounced differences in stimulable bioluminescence measured with bathyphotometers in Vestfjord, Norway in September 1990 correlated with simultaneous ship-board laboratory experiments. Cells of both the photosynthetic Ceratium fusus and heterotrophic Protoperidinium curtipes showed a pronounced inhibition of bioluminescence during the day and maximum bioluminescence at night.

Climatic events and bio-physical sequences involved in red tide formation have been characterized by mnemonic symbols and applied to geographical regions with spatial scales from meters to hundreds of kilometers and temporal scales ranging from daily to annual. Red tides may represent selections for optimization for sexual mating and for delivery of sexual or overwintering benthic cysts to 'seed bed' areas. A frontal convergence zone at the seaward edge of upwelling regions can exist and be a source of dinoflagellates transported into nearshore waters below a pycnocline. The physical hydrographic integrity of red tide surface patches enhances transport within geostrophic surface current jets with minimal dilution losses. Stepwise emigration and colonization are fortuitous consequences of red tide formation. Anthropogenic hypereutrophication along coastlines may have enhanced the efficiencies of stepwise emigrations, permitting colonization of areas not previously accessible.

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This article is from Ecology and Evolution , volume 3 . Abstract Symbiotic dinoflagellates are unicellular photosynthetic algae that live in mutualistic symbioses with many marine organisms. Within the transcriptome of coral endosymbionts Symbiodinium sp. (type C3), we discovered the sequences of two novel and highly polymorphic hemoglobin-like genes and proposed their 3D protein structures. At the protein level, four isoforms shared between 87 and 97% sequence identity for Hb-1 and 78–99% for Hb-2, whereas between Hb-1 and Hb-2 proteins, only 15–21% sequence homology has been preserved. Phylogenetic analyses of the dinoflagellate encoding Hb sequences have revealed a separate evolutionary origin of the discovered globin genes and indicated the possibility of horizontal gene transfer. Transcriptional regulation of the Hb-like genes was studied in the reef-building coral Acropora aspera exposed to elevated temperatures (6–7°C above average sea temperature) over a 24-h period and a 72-h period, as well as to nutrient stress. Exposure to elevated temperatures resulted in an increased Hb-1 gene expression of 31% after 72 h only, whereas transcript abundance of the Hb-2 gene was enhanced by up to 59% by both 1-day and 3-day thermal stress conditions. Nutrient stress also increased gene expression of Hb-2 gene by 70%. Our findings describe the differential expression patterns of two novel Hb genes from symbiotic dinoflagellates and their polymorphic nature. Furthermore, the inducible nature of Hb-2 gene by both thermal and nutrient stressors indicates a prospective role of this form of hemoglobin in the initial coral–algal responses to changes in environmental conditions. This novel hemoglobin has potential use as a stress biomarker.

This article is from Ecology and Evolution , volume 3 . Abstract Symbiotic dinoflagellates are unicellular photosynthetic algae that live in mutualistic symbioses with many marine organisms. Within the transcriptome of coral endosymbionts Symbiodinium sp. (type C3), we discovered the sequences of two novel and highly polymorphic hemoglobin-like genes and proposed their 3D protein structures. At the protein level, four isoforms shared between 87 and 97% sequence identity for Hb-1 and 78–99% for Hb-2, whereas between Hb-1 and Hb-2 proteins, only 15–21% sequence homology has been preserved. Phylogenetic analyses of the dinoflagellate encoding Hb sequences have revealed a separate evolutionary origin of the discovered globin genes and indicated the possibility of horizontal gene transfer. Transcriptional regulation of the Hb-like genes was studied in the reef-building coral Acropora aspera exposed to elevated temperatures (6–7°C above average sea temperature) over a 24-h period and a 72-h period, as well as to nutrient stress. Exposure to elevated temperatures resulted in an increased Hb-1 gene expression of 31% after 72 h only, whereas transcript abundance of the Hb-2 gene was enhanced by up to 59% by both 1-day and 3-day thermal stress conditions. Nutrient stress also increased gene expression of Hb-2 gene by 70%. Our findings describe the differential expression patterns of two novel Hb genes from symbiotic dinoflagellates and their polymorphic nature. Furthermore, the inducible nature of Hb-2 gene by both thermal and nutrient stressors indicates a prospective role of this form of hemoglobin in the initial coral–algal responses to changes in environmental conditions. This novel hemoglobin has potential use as a stress biomarker.

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 Paralytic shellfish poisoning (PSP) toxins are potent environmental neurotoxins mainly produced by marien dinoflagellates. Alexandrium spp. are the most abundant and widespread producer of saxitoxin (STX). Currently, the evolutionary history that resulted in the curious cross-kingdom distribution of STX-synthesis remained unclear. However, the increasing number of findings of toxin-producing bacteria in dinoflagellate supports the hypothesis of the bacterial origin of PSP toxins. Addtionally, evidence that there are specific symbiosis bacterial taxa associated with phytoplankton indicates the presence of specific selective mechanisms between them, and implies that the symbiosis bacteria have some vital functions to the benefit of the dinoflagellates. Culture-independent high-throughput pyrosequencing analysis is able to provide a thorough description of microbiota community in environmental samples, which also helps to reveal their potential function. This paper aims to demonstrate the biodiversity of the bacteria closely associated with two toxic dinoflagellate strains, A. tamarense and A. minutum using the pyrosequencing method.

Despite strong interest in short term process effects on dinoflagellates there have been few investigations on the seasonality of marine bioluminescence. Long term aspects of the development of bioluminescence are unknown for most oceans. The present study was designed to cast light on this question. A station for measuring bioluminescence was established in August 1993 at San Clemente Island (SCI), 100 km offshore of Southern California. Bioluminescence was measured with a moored bathyphotometer (MOORDEX) hourly through February 1996. Other environmental parameters such as nutrients, chlorophyll, and associated plankton species were measured and collected on a monthly and quarterly basis (Lapota et al. 1997). In the present study, plankton samples were collected and tested for bioluminescence on a quarterly basis to: 1) determine which dinoflagellate species were bioluminescent and 2) observe differences in light output on a seasonal basis. The latter is an important consideration because seasonal changes in bioluminescence from dinoflagellates might possibly indicate a response to regional seasonal environmental changes. These factors include the available nutrients and light for the photosynthetic species (Ceratium, Gonyaulax1, Pyrocystis) and the availability of diatoms and smaller algal cells consumed by the heterotrophic Protoperidinium dinoflagellates. Seasonal changes in light output will affect the bioluminescence light budget of all species. Published light budgets are limited and specific for limited oceanic areas, the number of species tested, or modeled to predict bioluminescence output based on the calculated cell surface area. This study will complement earlier laboratory work and enlarge these observations by identifying distinct seasonal differences in bioluminescence of open ocean dinoflagellates over a two year period.

This article is from PeerJ , volume 2 . Abstract Symbiodinium, a large group of dinoflagellates, live in symbiosis with marine protists, invertebrate metazoans, and free-living in the environment. Symbiodinium are functionally variable and play critical energetic roles in symbiosis. Our knowledge of Symbiodinium has been historically constrained by the limited number of molecular markers available to study evolution in the genus. Here we compare six functional genes, representing three cellular compartments, in the nine known Symbiodinium lineages. Despite striking similarities among the single gene phylogenies from distinct organelles, none were evolutionarily identical. A fully concatenated reconstruction, however, yielded a well-resolved topology identical to the current benchmark nr28S gene. Evolutionary rates differed among cellular compartments and clades, a pattern largely driven by higher rates of evolution in the chloroplast genes of Symbiodinium clades D2 and I. The rapid rates of evolution observed amongst these relatively uncommon Symbiodinium lineages in the functionally critical chloroplast may translate into potential innovation for the symbiosis. The multi-gene analysis highlights the potential power of assessing genome-wide evolutionary patterns using recent advances in sequencing technology and emphasizes the importance of integrating ecological data with more comprehensive sampling of free-living and symbiotic Symbiodinium in assessing the evolutionary adaptation of this enigmatic dinoflagellate.

Life Sciences Contributions 150 Bibliography: p. 55-61

Life Sciences Contributions 150 Bibliography: p. 55-61

This article is from Genome Biology and Evolution , volume 5 . Abstract The dinoflagellates are an evolutionarily and ecologically important group of microbial eukaryotes. Previous work suggests that horizontal gene transfer (HGT) is an important source of gene innovation in these organisms. However, dinoflagellate genomes are notoriously large and complex, making genomic investigation of this phenomenon impractical with currently available sequencing technology. Fortunately, de novo transcriptome sequencing and assembly provides an alternative approach for investigating HGT. We sequenced the transcriptome of the dinoflagellate Alexandrium tamarense Group IV to investigate how HGT has contributed to gene innovation in this group. Our comprehensive A. tamarense Group IV gene set was compared with those of 16 other eukaryotic genomes. Ancestral gene content reconstruction of ortholog groups shows that A. tamarense Group IV has the largest number of gene families gained (314–1,563 depending on inference method) relative to all other organisms in the analysis (0–782). Phylogenomic analysis indicates that genes horizontally acquired from bacteria are a significant proportion of this gene influx, as are genes transferred from other eukaryotes either through HGT or endosymbiosis. The dinoflagellates also display curious cases of gene loss associated with mitochondrial metabolism including the entire Complex I of oxidative phosphorylation. Some of these missing genes have been functionally replaced by bacterial and eukaryotic xenologs. The transcriptome of A. tamarense Group IV lends strong support to a growing body of evidence that dinoflagellate genomes are extraordinarily impacted by HGT.

Phytoplankton bioassays have been used as biological tools in assessing environmental impact from contaminants. Series of experiments were designed to measure the acute and sublethal effects of heavy metals (tributyltin, copper, and zinc) and storm drain effluent on the light output from marine bioluminescent dinoflagellates (Pyrocystis lunula in earlier experiments and Gonyaulax polyedra in later experiments). Cultured cells were exposed to various concentrations of a metal or storm drain effluent from hours up to 11 days. Measurable differences in light output have been observed in as little as 3 h when compared to control cells.... CIVAPP: Environmental programs, CIVAPP: Marine biology, CIVAPP: Analytical chemistry.

Phytoplankton bioassays have been used as biological tools in assessing environmental impact from contaminants. Series of experiments were designed to measure the acute and sublethal effects of heavy metals (tributyltin, copper, and zinc) and storm drain effluent on the light output from marine bioluminescent dinoflagellates (Pyrocystis lunula in earlier experiments and Gonyaulax polyedra in later experiments). Cultured cells were exposed to various concentrations of a metal or storm drain effluent from hours up to 11 days. Measurable differences in light output have been observed in as little as 3 h when compared to control cells.... CIVAPP: Environmental programs, CIVAPP: Marine biology, CIVAPP: Analytical chemistry.

Phytoplankton bioassays have been used as biological tools in assessing environmental impact from contaminants. Series of experiments were designed to measure the acute and sublethal effects of heavy metals (tributyltin, copper, and zinc) and storm drain effluent on the light output from marine bioluminescent dinoflagellates (Pyrocystis lunula in earlier experiments and Gonyaulax polyedra in later experiments). Cultured cells were exposed to various concentrations of a metal or storm drain effluent from hours up to 11 days. Measurable differences in light output have been observed in as little as 3 h when compared to control cells.... CIVAPP: Environmental programs, CIVAPP: Marine biology, CIVAPP: Analytical chemistry.

Outreach for National Science Foundation Project: Group-Specific Diatom Silica Production in a Coastal Upwelling System In coastal regions, diatoms and dinoflagellates play important roles in the food web. Below are 3-d object files (OBJ) for five coastal genera of phytoplankton including: Diatoms - Chaetoceros sp. (pictured, left) Odontella sp. Pseudo-nitzschia (pictured, right) Dinoflagellates - Karenia brevis Ceratium sp. File Produced by: Marine Microalgae Research Associates LLC Mr. Adam Nienow, [email protected] Files Distributed by: Dr. Jeffrey Krause Dauphin Island Sea Lab and the Marine Science Institute (U. California Santa Barbara) These models were created using National Science Foundation funding (Biological Oceanography program grant OCE-1155663 awarded to Jeffrey W. Krause), and are therefore in the Public Domain. These phytoplankton models were produced using funds from a grant by the US National Science Foundation (Grant OCE-1155663) to support research and education.

Outreach for National Science Foundation Project: Group-Specific Diatom Silica Production in a Coastal Upwelling System In coastal regions, diatoms and dinoflagellates play important roles in the food web. Below are 3-d object files (OBJ) for five coastal genera of phytoplankton including: Diatoms - Chaetoceros sp. (pictured, left) Odontella sp. Pseudo-nitzschia (pictured, right) Dinoflagellates - Karenia brevis Ceratium sp. File Produced by: Marine Microalgae Research Associates LLC Mr. Adam Nienow, [email protected] Files Distributed by: Dr. Jeffrey Krause Dauphin Island Sea Lab and the Marine Science Institute (U. California Santa Barbara) These models were created using National Science Foundation funding (Biological Oceanography program grant OCE-1155663 awarded to Jeffrey W. Krause), and are therefore in the Public Domain. These phytoplankton models were produced using funds from a grant by the US National Science Foundation (Grant OCE-1155663) to support research and education.

Bioluminescence in two species of dinoflagellates, Pyrocystis lunula and Gonyaulax polyedra, was stimulated when small pressure changes occured. At an initial pressure of 1 atm, a pressure decrease rate of 0.25 + or - 0.04 atm/s was the mean decrease threshold for P. lunula. Small variations in this threshold occured at a higher initial pressure and at different times during the circadian cycle. Pressure decreases were much more effective than pressure increases. For G. polyedra, a pressure change rate of at least 0.95 atm/s was required to stimulate bioluminescence. Pressure increases and decreases were both effective, but decreases were more effective than increases. The variation in results did not lend itself to statistical analysis.

We explore a novel approach towards quantification of paleo-ecological signals from non-analogue microfossil assemblages by quantifying relations between assemblages and high-quality geochemical and sedimentological data from sedimentary archives. We test this approach using one group of microfossils, the organic cysts of dinoflagellates (dinocysts), which are widely used in shelf and open marine settings for biostratigraphy and reconstructions of past environments and environmental change. Similar to other microfossil groups, dinocysts can be used to reconstruct environments with relatively high confidence for recent time periods, as species affinities can be derived from observational and instrumental data. In the absence of such data, the ecology of extinct species is much less certain and as a result reconstructions in deep time are often limited to qualitative interpretations. To explore if quantitative empirical relations between extinct dinocysts and high-quality geochemical data can be established, we study a major event of climate change, the Paleocene-Eocene Thermal Maximum (PETM; ~56 Ma ago). The PETM is a particularly suitable period for this exercise as there is a multitude of large environmental perturbations associated with the transient global warming, such as deoxygenation, sea level rise and an accelerated hydrological cycle. The synthesized published dataset exhibits better spatial and temporal coverage compared to any other period in deep time. We extract empirical relations for the abundance of previously proposed paleoecological groups as a function of independent environmental proxies for example, sea surface temperature and terrestrial organic matter input. The results unequivocally illustrate that many dinocysts show relations to several of the reconstructed environmental variables. Notably, we show that one genus (Apectodinium) and an ecogroup (epicystal Goniodomidae) required sea surface temperatures in excess of 20 °C, and 25 °C, respectively, while one species (Florentinia reichartii) was only abundant between 30 and 35 °C. Other groups apparently favored either a limited (Spiniferites) or high (Senegalinium) terrestrial input to the study site, relating to salinity, nutrient levels or suspended sediment load (i.e. murkiness). Crucially, our work shows that the validation and quantification of ecological signals by independent environmental proxy data provides the opportunity to extract more quantitative information from a wide range of (non-analogue) microfossil assemblages. While this approach is not limited to any specific group of microfossils (or macrofossils), we stress that proper calibration datasets, high-quality sedimentological and geochemical proxy records, are needed and should ideally have decent geographical coverage and include one or more environmental perturbations. Using this approach such empirical relations can be established for a wide range of microfossil groups that have highly complementary geological records, which increases the value of existing data and ensures future application of microfossil-based paleoecology.

Phytoplankton bioassays have been used as biological tools in assessing environmental contamination. In our laboratory, a simple bioassay has been developed which measures the light output from bioluminescence dinoflagellates for assessment of toxic effects when exposed to a single toxicant or mixture. Successful use of this type of bioassay has provided data on the acute response and has demonstrated the chronic effects, from hours up to 11 days, on dinoflagellate cells of Pyrocystis lunula and Gonyaulax polyedra upon exposure to several metals and storm drain effluent. Dinoflagellate cells were exposed to various concentrations of tributyltin chloride (TBTCI), copper (11) sulfate (CUS04), zinc sulfate (ZnSO4), or storm drain effluent. Stimulable bioluminescence was measured at each test period (3 or 4 h, 24 h, 48 h, 72 h, etc.) following setup for all assays. Cells were kept in the dark for 3 or 4 h prior to testing. Stirring the cells within the chamber stimulated maximum bioluminescence from the dinoflagellates. An IC50 (an estimated concentration that is likely to cause a 50% reduction in light output) was estimated for all assays. The trend of light reduction as a response to increasing dose level of test article was observed in all assays. A reduction in light output was measured from cells exposed to 1.6, 4.2, and 12.8 ug/L TBTCI. The IC50 decreased from 8.5 ug/L at 120 h to 3.0 ug/L at 264 h. The cells exposed to 6.25%, 12.5%, and 25.0% storm drain effluent exhibited a statistically significant (P=0.05) reduction in light output in as little as 3 h exposure.

Phytoplankton bioassays have been used as biological tools in assessing environmental contamination. In our laboratory, a simple bioassay has been developed which measures the light output from bioluminescence dinoflagellates for assessment of toxic effects when exposed to a single toxicant or mixture. Successful use of this type of bioassay has provided data on the acute response and has demonstrated the chronic effects, from hours up to 11 days, on dinoflagellate cells of Pyrocystis lunula and Gonyaulax polyedra upon exposure to several metals and storm drain effluent. Dinoflagellate cells were exposed to various concentrations of tributyltin chloride (TBTCI), copper (11) sulfate (CUS04), zinc sulfate (ZnSO4), or storm drain effluent. Stimulable bioluminescence was measured at each test period (3 or 4 h, 24 h, 48 h, 72 h, etc.) following setup for all assays. Cells were kept in the dark for 3 or 4 h prior to testing. Stirring the cells within the chamber stimulated maximum bioluminescence from the dinoflagellates. An IC50 (an estimated concentration that is likely to cause a 50% reduction in light output) was estimated for all assays. The trend of light reduction as a response to increasing dose level of test article was observed in all assays. A reduction in light output was measured from cells exposed to 1.6, 4.2, and 12.8 ug/L TBTCI. The IC50 decreased from 8.5 ug/L at 120 h to 3.0 ug/L at 264 h. The cells exposed to 6.25%, 12.5%, and 25.0% storm drain effluent exhibited a statistically significant (P=0.05) reduction in light output in as little as 3 h exposure.

This article is from PLoS ONE , volume 9 . Abstract We investigated the distribution of bioluminescent dinoflagellates in the Patagonian Shelf region using “universal” PCR primers for the dinoflagellate luciferase gene. Luciferase gene sequences and single cell PCR tests, in conjunction with taxonomic identification by microscopy, allowed us to identify and quantify bioluminescent dinoflagellates. We compared these data to coincidental discrete optical measurements of stimulable bioluminescence intensity. Molecular detection of the luciferase gene showed that bioluminescent dinoflagellates were widespread across the majority of the Patagonian Shelf region. Their presence was comparatively underestimated by optical bioluminescence measurements, whose magnitude was affected by interspecific differences in bioluminescence intensity and by the presence of other bioluminescent organisms. Molecular and microscopy data showed that the complex hydrography of the area played an important role in determining the distribution and composition of dinoflagellate populations. Dinoflagellates were absent south of the Falkland Islands where the cold, nutrient-rich, and well-mixed waters of the Falklands Current favoured diatoms instead. Diverse populations of dinoflagellates were present in the warmer, more stratified waters of the Patagonian Shelf and Falklands Current as it warmed northwards. Here, the dinoflagellate population composition could be related to distinct water masses. Our results provide new insight into the prevalence of bioluminescent dinoflagellates in Patagonian Shelf waters and demonstrate that a molecular approach to the detection of bioluminescent dinoflagellates in natural waters is a promising tool for ecological studies of these organisms.

This article is from Frontiers in Microbiology , volume 5 . Abstract Some microalgae in nature live in symbiosis with microorganisms that can enhance or inhibit growth, thus influencing the dynamics of phytoplankton blooms. In spite of the great ecological importance of these interactions, very few defined laboratory systems are available to study them in detail. Here we present a co-cultivation system consisting of the toxic phototrophic dinoflagellate Prorocentrum minimum and the photoheterotrophic alphaproteobacterium Dinoroseobacter shibae. In a mineral medium lacking a carbon source, vitamins for the bacterium and the essential vitamin B12 for the dinoflagellate, growth dynamics reproducibly went from a mutualistic phase, where both algae and bacteria grow, to a pathogenic phase, where the algae are killed by the bacteria. The data show a “Jekyll and Hyde” lifestyle that had been proposed but not previously demonstrated. We used RNAseq and microarray analysis to determine which genes of D. shibae are transcribed and differentially expressed in a light dependent way at an early time-point of the co-culture when the bacterium grows very slowly. Enrichment of bacterial mRNA for transcriptome analysis was optimized, but none of the available methods proved capable of removing dinoflagellate ribosomal RNA completely. RNAseq showed that a phasin encoding gene (phaP1) which is part of the polyhydroxyalkanoate (PHA) metabolism operon represented approximately 10% of all transcripts. Five genes for aerobic anoxygenic photosynthesis were down-regulated in the light, indicating that the photosynthesis apparatus was functional. A betaine-choline-carnitine-transporter (BCCT) that may be used for dimethylsulfoniopropionate (DMSP) uptake was the highest up-regulated gene in the light. The data suggest that at this early mutualistic phase of the symbiosis, PHA degradation might be the main carbon and energy source of D. shibae, supplemented in the light by degradation of DMSP and aerobic anoxygenic photosynthesis.

Our goal is to continue to use biotechnological techniques to study the genetic bases of light- and nutrient-regulation of photosynthetic light- harvesting complexes in marine dinoflagellates. We chose the peridinin- chlorophyll a-protein (PCP) complexes of dinoflagellates as a model system for proposed genetic analyses. Since these phytoplankton are a spectral representative of the large group of marine algae whose light-harvesting components are dominated by blue-light absorbing xanthophylls. knowledge gained through study of the PCP system may also provide insights into the closely related fucoxanthin-system of diatoms, chrysophytes and brown algae.

Our goal is to continue to use biotechnological techniques to study the genetic bases of light- and nutrient-regulation of photosynthetic light- harvesting complexes in marine dinoflagellates. We chose the peridinin- chlorophyll a-protein (PCP) complexes of dinoflagellates as a model system for proposed genetic analyses. Since these phytoplankton are a spectral representative of the large group of marine algae whose light-harvesting components are dominated by blue-light absorbing xanthophylls. knowledge gained through study of the PCP system may also provide insights into the closely related fucoxanthin-system of diatoms, chrysophytes and brown algae.

Our goal is to continue to use biotechnological techniques to study the genetic bases of light- and nutrient-regulation of photosynthetic light- harvesting complexes in marine dinoflagellates. We chose the peridinin- chlorophyll a-protein (PCP) complexes of dinoflagellates as a model system for proposed genetic analyses. Since these phytoplankton are a spectral representative of the large group of marine algae whose light-harvesting components are dominated by blue-light absorbing xanthophylls. knowledge gained through study of the PCP system may also provide insights into the closely related fucoxanthin-system of diatoms, chrysophytes and brown algae.

Our goal is to continue to use biotechnological techniques to study the genetic bases of light- and nutrient- regulation of photosynthetic light- harvesting complexes in marine dinoflagellates and their consequences for the bio-optical features of these algae. The studies are significant to determining the molecular bases of environmental regulation of gene expression and photosynthetic performance in marine phytoplankton. Results also contribute to understanding the linkages between light environments and cell optical properties, key elements in physiologically-based bio-optical models being developed to predict ocean primary production. Keywords: Photosynthesis; Clones; DNA; PCP (Peridinin-Chlorophyll A-protein).

Our goal is to continue to use biotechnological techniques to study the genetic bases of light- and nutrient- regulation of photosynthetic light- harvesting complexes in marine dinoflagellates and their consequences for the bio-optical features of these algae. The studies are significant to determining the molecular bases of environmental regulation of gene expression and photosynthetic performance in marine phytoplankton. Results also contribute to understanding the linkages between light environments and cell optical properties, key elements in physiologically-based bio-optical models being developed to predict ocean primary production. Keywords: Photosynthesis; Clones; DNA; PCP (Peridinin-Chlorophyll A-protein).

Our goal is to continue to use biotechnological techniques to study the genetic bases of light- and nutrient- regulation of photosynthetic light- harvesting complexes in marine dinoflagellates and their consequences for the bio-optical features of these algae. The studies are significant to determining the molecular bases of environmental regulation of gene expression and photosynthetic performance in marine phytoplankton. Results also contribute to understanding the linkages between light environments and cell optical properties, key elements in physiologically-based bio-optical models being developed to predict ocean primary production. Keywords: Photosynthesis; Clones; DNA; PCP (Peridinin-Chlorophyll A-protein).

Source: Digital Library of India Scanning Centre: C-DAC, Noida Source Library: Central Library, Bits- Pilani Date Accessioned: 6/24/2015 3:07 The Digital Library of India was a project under the auspices of the Government of India.

This article is from Marine Drugs , volume 12 . Abstract The identification of toxin-producing dinoflagellates for monitoring programmes and bio-compound discovery requires considerable taxonomic expertise. It can also be difficult to morphologically differentiate toxic and non-toxic species or strains. Various molecular methods have been used for dinoflagellate identification and detection, and this study describes the development of eight real-time polymerase chain reaction (PCR) assays targeting the large subunit ribosomal RNA (LSU rRNA) gene of species from the genera Gymnodinium, Karenia, Karlodinium, and Takayama. Assays proved to be highly specific and sensitive, and the assay for G. catenatum was further developed for quantification in response to a bloom in Manukau Harbour, New Zealand. The assay estimated cell densities from environmental samples as low as 0.07 cells per PCR reaction, which equated to three cells per litre. This assay not only enabled conclusive species identification but also detected the presence of cells below the limit of detection for light microscopy. This study demonstrates the usefulness of real-time PCR as a sensitive and rapid molecular technique for the detection and quantification of micro-algae from environmental samples.

Marine thecate heterotrophic dinoflagellates likely play an important role in the consumption of primary productivity and in the trophic structure of the plankton, yet we know little about these species. This thesis expanded our understanding of the autecology and evolutionary history of the Protoperidinium and diplopsalids. The distributions of Protoperidinium species off the southwestern coast of Ireland were influenced by physical oceanographic conditions coupled with the availability of preferred prey. The distributions of individual Protoperidinium species varied widely from the distribution of total Protoperidinium, indicating differences in ecologies among species. Certain species of Protoperidinium co-occurred with known preferred phytoplankton prey species. Concentrations of other Protoperidinium species were not related to those of any particular phytoplankton species, indicating that these Protoperidinium may rely on phytoplankton or other food sources beyond those already known, may not be species specific selective feeders, or may have become uncoupled from their preferred prey. The description of the sexual and asexual life history of Protoperidinium steidingerae provided d%the first account of the life history of any Protoperidinium species. Asexual division occurred by eleutheroschisis within a temporary, immotile cyst, yielding two daughter cells. Daughter cells were initially round and half to two-thirds the size of parent cells, then rapidly increased in size, forming horns before separating. Sexual reproduction was constitutive in clonal cultures, indicating that the species may be homothallic. Fusing gametes were isogamous, and resulted in a planozygote with two longitudinal flagella. Hypnozygotes had a mandatory dormancy period of ca. 70 days. Germination resulted in planomeiocytes with two longitudinal flagella. Nuclear cyclosis may occur in the planomeiocyte stage.

This article is from Scientific Reports , volume 4 . Abstract The stability of cnidarian-dinoflagellate (genus Symbiodinium spp.) endosymbioses depends on the regulation of nutrient transport between Symbiodinium populations and their hosts. Previously, we successfully induced the production of lipid droplets in the free-living cultured Symbiodinium (clade B) under the nitrogen-deprivation condition for 5 days. Therefore, the present study aimed at understanding the disruption of the endosymbiotic relationship between the cnidarians and dinoflagellates by nitrogen deprivation using Aiptasia pulchella as an example. Transmission electron micrographs revealed the formation of lipid droplets induced by nitrogen deprivation, and the lipid analyses further showed that polyunsaturated fatty acids were drastically enriched in Symbiodinium after 30 days of nitrogen deprivation, although these were unaffected after 5 days of nitrogen starvation. The present study also suggested that the host provided nitrogen to the symbiotic cells during short-term environmental stress. However, the relationship started to deteriorate after 30 days. These findings provide a more detailed understanding of the mechanisms of the symbiotic relationship between the symbiotic dinoflagellates in terms of the nitrogen source, which might provide more information for the explanation of the regulatory mechanism underlying endosymbiotic associations.

This article is from Scientific Reports , volume 4 . Abstract The stability of cnidarian-dinoflagellate (genus Symbiodinium spp.) endosymbioses depends on the regulation of nutrient transport between Symbiodinium populations and their hosts. Previously, we successfully induced the production of lipid droplets in the free-living cultured Symbiodinium (clade B) under the nitrogen-deprivation condition for 5 days. Therefore, the present study aimed at understanding the disruption of the endosymbiotic relationship between the cnidarians and dinoflagellates by nitrogen deprivation using Aiptasia pulchella as an example. Transmission electron micrographs revealed the formation of lipid droplets induced by nitrogen deprivation, and the lipid analyses further showed that polyunsaturated fatty acids were drastically enriched in Symbiodinium after 30 days of nitrogen deprivation, although these were unaffected after 5 days of nitrogen starvation. The present study also suggested that the host provided nitrogen to the symbiotic cells during short-term environmental stress. However, the relationship started to deteriorate after 30 days. These findings provide a more detailed understanding of the mechanisms of the symbiotic relationship between the symbiotic dinoflagellates in terms of the nitrogen source, which might provide more information for the explanation of the regulatory mechanism underlying endosymbiotic associations.

This article is from Scientific Reports , volume 4 . Abstract The stability of cnidarian-dinoflagellate (genus Symbiodinium spp.) endosymbioses depends on the regulation of nutrient transport between Symbiodinium populations and their hosts. Previously, we successfully induced the production of lipid droplets in the free-living cultured Symbiodinium (clade B) under the nitrogen-deprivation condition for 5 days. Therefore, the present study aimed at understanding the disruption of the endosymbiotic relationship between the cnidarians and dinoflagellates by nitrogen deprivation using Aiptasia pulchella as an example. Transmission electron micrographs revealed the formation of lipid droplets induced by nitrogen deprivation, and the lipid analyses further showed that polyunsaturated fatty acids were drastically enriched in Symbiodinium after 30 days of nitrogen deprivation, although these were unaffected after 5 days of nitrogen starvation. The present study also suggested that the host provided nitrogen to the symbiotic cells during short-term environmental stress. However, the relationship started to deteriorate after 30 days. These findings provide a more detailed understanding of the mechanisms of the symbiotic relationship between the symbiotic dinoflagellates in terms of the nitrogen source, which might provide more information for the explanation of the regulatory mechanism underlying endosymbiotic associations.

This article is from Scientific Reports , volume 4 . Abstract The stability of cnidarian-dinoflagellate (genus Symbiodinium spp.) endosymbioses depends on the regulation of nutrient transport between Symbiodinium populations and their hosts. Previously, we successfully induced the production of lipid droplets in the free-living cultured Symbiodinium (clade B) under the nitrogen-deprivation condition for 5 days. Therefore, the present study aimed at understanding the disruption of the endosymbiotic relationship between the cnidarians and dinoflagellates by nitrogen deprivation using Aiptasia pulchella as an example. Transmission electron micrographs revealed the formation of lipid droplets induced by nitrogen deprivation, and the lipid analyses further showed that polyunsaturated fatty acids were drastically enriched in Symbiodinium after 30 days of nitrogen deprivation, although these were unaffected after 5 days of nitrogen starvation. The present study also suggested that the host provided nitrogen to the symbiotic cells during short-term environmental stress. However, the relationship started to deteriorate after 30 days. These findings provide a more detailed understanding of the mechanisms of the symbiotic relationship between the symbiotic dinoflagellates in terms of the nitrogen source, which might provide more information for the explanation of the regulatory mechanism underlying endosymbiotic associations.

This article is from Scientific Reports , volume 4 . Abstract The stability of cnidarian-dinoflagellate (genus Symbiodinium spp.) endosymbioses depends on the regulation of nutrient transport between Symbiodinium populations and their hosts. Previously, we successfully induced the production of lipid droplets in the free-living cultured Symbiodinium (clade B) under the nitrogen-deprivation condition for 5 days. Therefore, the present study aimed at understanding the disruption of the endosymbiotic relationship between the cnidarians and dinoflagellates by nitrogen deprivation using Aiptasia pulchella as an example. Transmission electron micrographs revealed the formation of lipid droplets induced by nitrogen deprivation, and the lipid analyses further showed that polyunsaturated fatty acids were drastically enriched in Symbiodinium after 30 days of nitrogen deprivation, although these were unaffected after 5 days of nitrogen starvation. The present study also suggested that the host provided nitrogen to the symbiotic cells during short-term environmental stress. However, the relationship started to deteriorate after 30 days. These findings provide a more detailed understanding of the mechanisms of the symbiotic relationship between the symbiotic dinoflagellates in terms of the nitrogen source, which might provide more information for the explanation of the regulatory mechanism underlying endosymbiotic associations.

This article is from Scientific Reports , volume 4 . Abstract The stability of cnidarian-dinoflagellate (genus Symbiodinium spp.) endosymbioses depends on the regulation of nutrient transport between Symbiodinium populations and their hosts. Previously, we successfully induced the production of lipid droplets in the free-living cultured Symbiodinium (clade B) under the nitrogen-deprivation condition for 5 days. Therefore, the present study aimed at understanding the disruption of the endosymbiotic relationship between the cnidarians and dinoflagellates by nitrogen deprivation using Aiptasia pulchella as an example. Transmission electron micrographs revealed the formation of lipid droplets induced by nitrogen deprivation, and the lipid analyses further showed that polyunsaturated fatty acids were drastically enriched in Symbiodinium after 30 days of nitrogen deprivation, although these were unaffected after 5 days of nitrogen starvation. The present study also suggested that the host provided nitrogen to the symbiotic cells during short-term environmental stress. However, the relationship started to deteriorate after 30 days. These findings provide a more detailed understanding of the mechanisms of the symbiotic relationship between the symbiotic dinoflagellates in terms of the nitrogen source, which might provide more information for the explanation of the regulatory mechanism underlying endosymbiotic associations.

This article is from Scientific Reports , volume 4 . Abstract The stability of cnidarian-dinoflagellate (genus Symbiodinium spp.) endosymbioses depends on the regulation of nutrient transport between Symbiodinium populations and their hosts. Previously, we successfully induced the production of lipid droplets in the free-living cultured Symbiodinium (clade B) under the nitrogen-deprivation condition for 5 days. Therefore, the present study aimed at understanding the disruption of the endosymbiotic relationship between the cnidarians and dinoflagellates by nitrogen deprivation using Aiptasia pulchella as an example. Transmission electron micrographs revealed the formation of lipid droplets induced by nitrogen deprivation, and the lipid analyses further showed that polyunsaturated fatty acids were drastically enriched in Symbiodinium after 30 days of nitrogen deprivation, although these were unaffected after 5 days of nitrogen starvation. The present study also suggested that the host provided nitrogen to the symbiotic cells during short-term environmental stress. However, the relationship started to deteriorate after 30 days. These findings provide a more detailed understanding of the mechanisms of the symbiotic relationship between the symbiotic dinoflagellates in terms of the nitrogen source, which might provide more information for the explanation of the regulatory mechanism underlying endosymbiotic associations.

This article is from Scientific Reports , volume 4 . Abstract The stability of cnidarian-dinoflagellate (genus Symbiodinium spp.) endosymbioses depends on the regulation of nutrient transport between Symbiodinium populations and their hosts. Previously, we successfully induced the production of lipid droplets in the free-living cultured Symbiodinium (clade B) under the nitrogen-deprivation condition for 5 days. Therefore, the present study aimed at understanding the disruption of the endosymbiotic relationship between the cnidarians and dinoflagellates by nitrogen deprivation using Aiptasia pulchella as an example. Transmission electron micrographs revealed the formation of lipid droplets induced by nitrogen deprivation, and the lipid analyses further showed that polyunsaturated fatty acids were drastically enriched in Symbiodinium after 30 days of nitrogen deprivation, although these were unaffected after 5 days of nitrogen starvation. The present study also suggested that the host provided nitrogen to the symbiotic cells during short-term environmental stress. However, the relationship started to deteriorate after 30 days. These findings provide a more detailed understanding of the mechanisms of the symbiotic relationship between the symbiotic dinoflagellates in terms of the nitrogen source, which might provide more information for the explanation of the regulatory mechanism underlying endosymbiotic associations.

This article is from Scientific Reports , volume 4 . Abstract The stability of cnidarian-dinoflagellate (genus Symbiodinium spp.) endosymbioses depends on the regulation of nutrient transport between Symbiodinium populations and their hosts. Previously, we successfully induced the production of lipid droplets in the free-living cultured Symbiodinium (clade B) under the nitrogen-deprivation condition for 5 days. Therefore, the present study aimed at understanding the disruption of the endosymbiotic relationship between the cnidarians and dinoflagellates by nitrogen deprivation using Aiptasia pulchella as an example. Transmission electron micrographs revealed the formation of lipid droplets induced by nitrogen deprivation, and the lipid analyses further showed that polyunsaturated fatty acids were drastically enriched in Symbiodinium after 30 days of nitrogen deprivation, although these were unaffected after 5 days of nitrogen starvation. The present study also suggested that the host provided nitrogen to the symbiotic cells during short-term environmental stress. However, the relationship started to deteriorate after 30 days. These findings provide a more detailed understanding of the mechanisms of the symbiotic relationship between the symbiotic dinoflagellates in terms of the nitrogen source, which might provide more information for the explanation of the regulatory mechanism underlying endosymbiotic associations.

This article is from Scientific Reports , volume 4 . Abstract The stability of cnidarian-dinoflagellate (genus Symbiodinium spp.) endosymbioses depends on the regulation of nutrient transport between Symbiodinium populations and their hosts. Previously, we successfully induced the production of lipid droplets in the free-living cultured Symbiodinium (clade B) under the nitrogen-deprivation condition for 5 days. Therefore, the present study aimed at understanding the disruption of the endosymbiotic relationship between the cnidarians and dinoflagellates by nitrogen deprivation using Aiptasia pulchella as an example. Transmission electron micrographs revealed the formation of lipid droplets induced by nitrogen deprivation, and the lipid analyses further showed that polyunsaturated fatty acids were drastically enriched in Symbiodinium after 30 days of nitrogen deprivation, although these were unaffected after 5 days of nitrogen starvation. The present study also suggested that the host provided nitrogen to the symbiotic cells during short-term environmental stress. However, the relationship started to deteriorate after 30 days. These findings provide a more detailed understanding of the mechanisms of the symbiotic relationship between the symbiotic dinoflagellates in terms of the nitrogen source, which might provide more information for the explanation of the regulatory mechanism underlying endosymbiotic associations.

This article is from Scientific Reports , volume 4 . Abstract The stability of cnidarian-dinoflagellate (genus Symbiodinium spp.) endosymbioses depends on the regulation of nutrient transport between Symbiodinium populations and their hosts. Previously, we successfully induced the production of lipid droplets in the free-living cultured Symbiodinium (clade B) under the nitrogen-deprivation condition for 5 days. Therefore, the present study aimed at understanding the disruption of the endosymbiotic relationship between the cnidarians and dinoflagellates by nitrogen deprivation using Aiptasia pulchella as an example. Transmission electron micrographs revealed the formation of lipid droplets induced by nitrogen deprivation, and the lipid analyses further showed that polyunsaturated fatty acids were drastically enriched in Symbiodinium after 30 days of nitrogen deprivation, although these were unaffected after 5 days of nitrogen starvation. The present study also suggested that the host provided nitrogen to the symbiotic cells during short-term environmental stress. However, the relationship started to deteriorate after 30 days. These findings provide a more detailed understanding of the mechanisms of the symbiotic relationship between the symbiotic dinoflagellates in terms of the nitrogen source, which might provide more information for the explanation of the regulatory mechanism underlying endosymbiotic associations.