The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform
Lei Wang - One of the best experts on this subject based on the ideXlab platform.
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morphology ultrastructure and molecular phylogeny of wangodinium sinense gen et sp nov gymnodiniales dinophyceae and revisiting of gymnodinium dorsalisulcum and gymnodinium impudicum
Journal of Phycology, 2018Co-Authors: Zhaohe Luo, Ying Zhong Tang, Kenneth Neil Mertens, Chui Pin Leaw, Po Teen Lim, Sing Tung Teng, Lei WangAbstract:The genus Gymnodinium includes many morphologically similar species, but molecular phylogenies show that it is polyphyletic. Eight strains of Gymnodinium impudicum, Gymnodinium dorsalisulcum and a novel Gymnodinium-like species from Chinese and Malaysian waters and the Mediterranean Sea were established. All of these strains were examined with light microscopy, scanning electron microscopy and transmission electron microscopy. SSU, LSU and internal transcribed spacers rDNA sequences were obtained. A new genus, Wangodinium, was erected to incorporate strains with a loop-shaped apical structure complex (ASC) comprising two rows of amphiesmal vesicles, here referred to as a new type of ASC. The chloroplasts of Wangodinium sinense are enveloped by two membranes. Pigment analysis shows that peridinin is the main Accessory Pigment in W. sinense. Wangodinium differs from other genera mainly in its unique ASC, and additionally differs from Gymnodinium in the absence of nuclear chambers, and from Lepidodinium in the absence of Chl b and nuclear chambers. New morphological information was provided for G. dorsalisulcum and G. impudicum, e.g., a short sulcal intrusion in G. dorsalisulcum; nuclear chambers in G. impudicum and G. dorsalisulcum; and a chloroplast enveloped by two membranes in G. impudicum. Molecular phylogeny was inferred using maximum likelihood and Bayesian inference with independent SSU and LSU rDNA sequences. Our results support the classification of Wangodinium within the Gymnodiniales sensu stricto clade and it is close to Lepidodinium. Our results also support the close relationship among G. dorsalisulcum, G. impudicum, and Barrufeta. Further research is needed to assign these Gymnodinium species to Barrufeta or to erect new genera.
Laurie L. Richardson - One of the best experts on this subject based on the ideXlab platform.
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remote sensing of algal bloom dynamicsnew research fuses remote sensing of aquatic ecosystems with algal Accessory Pigment analysis
BioScience, 1996Co-Authors: Laurie L. RichardsonAbstract:mhe last decade has seen rapid advances in two technologybased approaches to the study of algal biology: the use of remote sensing, which quantitatively measures light reflected from the surface of the earth, as a tool to study regional-scale aquatic ecosystem dynamics, and the refinement of techniques to identify and quantify algal Pigments. Although research in remote sensing has been driven by the ongoing development of new sensors, advances in Pigment analysis have essentially evolved from continual research in algal population dynamics, ecology, and physiology. Recent innovative results in both
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Algal Accessory Pigment Detection Using AVIRIS Image-Derived Spectral Radiance Data
1996Co-Authors: Laurie L. Richardson, Vincent G. AmbrosiaAbstract:Visual and derivative analyses of AVIRIS spectral data can be used to detect algal Accessory Pigments in aquatic communities. This capability extends the use of remote sensing for the study of aquatic ecosystems by allowing detection of taxonomically significant Pigment signatures which yield information about the type of algae present. Such information allows remote sensing-based assessment of aquatic ecosystem health, as in the detection of nuisance blooms of cyanobacteria or toxic blooms of dinoflagellates. Remote sensing of aquatic systems has traditionally focused on quantification of chlorophyll a, a photoreactive (and light-harvesting) Pigment which is common to all algae as well as cyanobacteria (bluegreen algae). Due to the ubiquitousness of this Pigment within algae, chl a is routinely measured to estimate algal biomass both during ground-truthing and using various airborne or satellite based sensors, including AVIRIS. Within the remote sensing and aquatic sciences communities, ongoing research has been performed to detect algal Accessory Pigments for assessment of algal population composition. This research is based on the fact that many algal Accessory Pigments are taxonomically significant, and all are spectrally unique. Aquatic scientists have been refining Pigment analysis techniques, primarily high performance liquid chromatography, or HPLC, to detect specific Pigments as a time-saving alternative to individual algal cell identifications and counts. Remote sensing scientists are investigating the use of Pigment signatures to construct Pigment libraries analogous to mineral spectral libraries used in geological remote sensing applications. The Accessory Pigment approach has been used successfully in remote sensing using data from the Thematic Mapper, low-altitude, multiple channel scanners, field spectroradiometers and the AVIRIS hyperspectral scanner. Due to spectral and spatial resolution capabilities, AVIRIS is the sensor of choice for such studies. We present here our results on detection of algal Accessory Pigments using AVIRIS data.
Zhaohe Luo - One of the best experts on this subject based on the ideXlab platform.
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morphology ultrastructure and molecular phylogeny of wangodinium sinense gen et sp nov gymnodiniales dinophyceae and revisiting of gymnodinium dorsalisulcum and gymnodinium impudicum
Journal of Phycology, 2018Co-Authors: Zhaohe Luo, Ying Zhong Tang, Kenneth Neil Mertens, Chui Pin Leaw, Po Teen Lim, Sing Tung Teng, Lei WangAbstract:The genus Gymnodinium includes many morphologically similar species, but molecular phylogenies show that it is polyphyletic. Eight strains of Gymnodinium impudicum, Gymnodinium dorsalisulcum and a novel Gymnodinium-like species from Chinese and Malaysian waters and the Mediterranean Sea were established. All of these strains were examined with light microscopy, scanning electron microscopy and transmission electron microscopy. SSU, LSU and internal transcribed spacers rDNA sequences were obtained. A new genus, Wangodinium, was erected to incorporate strains with a loop-shaped apical structure complex (ASC) comprising two rows of amphiesmal vesicles, here referred to as a new type of ASC. The chloroplasts of Wangodinium sinense are enveloped by two membranes. Pigment analysis shows that peridinin is the main Accessory Pigment in W. sinense. Wangodinium differs from other genera mainly in its unique ASC, and additionally differs from Gymnodinium in the absence of nuclear chambers, and from Lepidodinium in the absence of Chl b and nuclear chambers. New morphological information was provided for G. dorsalisulcum and G. impudicum, e.g., a short sulcal intrusion in G. dorsalisulcum; nuclear chambers in G. impudicum and G. dorsalisulcum; and a chloroplast enveloped by two membranes in G. impudicum. Molecular phylogeny was inferred using maximum likelihood and Bayesian inference with independent SSU and LSU rDNA sequences. Our results support the classification of Wangodinium within the Gymnodiniales sensu stricto clade and it is close to Lepidodinium. Our results also support the close relationship among G. dorsalisulcum, G. impudicum, and Barrufeta. Further research is needed to assign these Gymnodinium species to Barrufeta or to erect new genera.
Debashish Bhattacharya - One of the best experts on this subject based on the ideXlab platform.
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Tertiary Endosymbiosis Driven Genome Evolution in Dinoflagellate Algae
Molecular Biology and Evolution, 2005Co-Authors: Hwan Su Yoon, Jeremiah D. Hackett, Frances M. Van Dolah, Tetyana Nosenko, Kristy B. Lidie, Debashish BhattacharyaAbstract:Dinoflagellates are important aquatic primary producers and cause "red tides." The most widespread plastid (photosynthetic organelle) in these algae contains the unique Accessory Pigment peridinin. This plastid putatively originated via a red algal secondary endosymbiosis and has some remarkable features, the most notable being a genome that is reduced to 1-3 gene minicircles with about 14 genes (out of an original 130-200) remaining in the organelle and a nuclear-encoded proteobacterial Form II Rubisco. The "missing" plastid genes are relocated to the nucleus via a massive transfer unequaled in other photosynthetic eukaryotes. The fate of these characters is unknown in a number of dinoflagellates that have replaced the peridinin plastid through tertiary endosymbiosis. We addressed this issue in the fucoxanthin dinoflagellates (e.g., Karenia brevis) that contain a captured haptophyte plastid. Our multiprotein phylogenetic analyses provide robust support for the haptophyte plastid replacement and are consistent with a red algal origin of the chromalveolate plastid. We then generated an expressed sequence tag (EST) database of 5,138 unique genes from K. brevis and searched for nuclear genes of plastid function. The EST data indicate the loss of the ancestral peridinin plastid characters in K. brevis including the transferred plastid genes and Form II Rubisco. These results underline the remarkable ability of dinoflagellates to remodel their genomes through endosymbiosis and the considerable impact of this process on cell evolution.
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Research Article: Tertiary Endosymbiosis Driven Genome Evolution in Dinoflagellate Algae
2005Co-Authors: Hwan Su Yoon, Debashish Bhattacharya, Jeremiah D. Hackett, Frances M. Van Dolah, Tetyana Nosenko, Kristy B. Lidie, Roy J. CarverAbstract:Dinoflagellates are important aquatic primary producers and cause “red tides”. The most widespread plastid (photosynthetic organelle) in these algae contains the unique Accessory Pigment peridinin. This plastid putatively originated via a red algal secondary endosymbiosis and has some remarkable features, the most notable being a genome that is reduced to 1-3 gene minicircles with about 14 genes (out of an original 130-200) remaining in the organelle and a nuclear-encoded proteobacterial Form II Rubisco. The “missing” plastid genes are relocated to the nucleus via a massive transfer unequaled in other photosynthetic eukaryotes. The fate of these characters is unknown in a number of dinoflagellates that have replaced the peridinin plastid through tertiary endosymbiosis. We addressed this issue in the fucoxanthin dinoflagellates (e.g., Karenia brevis) that contain a captured haptophyte plastid. Our multiprotein phylogenetic analyses provide robust support for the haptophyte plastid replacement and are consistent with a red algal origin of the chromalveolate plastid. We then generated an expressed sequence tag (EST) database of 5,138 unique genes from K. brevis and searched for nuclear genes of plastid function. The EST data indicate the loss of the ancestral peridinin plastid characters in K. brevis including the transferred plastid genes and Form II Rubisco. These results underline the remarkable ability of dinoflagellates to remodel their genomes through endosymbiosis and the considerable impact of this process on cell evolution.
G M Hallegraeff - One of the best experts on this subject based on the ideXlab platform.
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takayama gen nov gymnodiniales dinophyceae a new genus of unarmored dinoflagellates with sigmoid apical grooves including the description of two new species
Journal of Phycology, 2003Co-Authors: Miguel F De Salas, Christopher J S Bolch, Lizeth Botes, Geraldine V Nash, Simon W Wright, G M HallegraeffAbstract:A new potentially ichthyotoxic dinoflagellate genus, Takayama de Salas, Bolch, Botes et Hallegraeff gen. nov., is described with two new species isolated from Tasmanian (Australia) and South African coastal waters: T. tasmanica de Salas, Bolch et Hallegraeff, sp. nov. and T. helix, de Salas, Bolch, Botes et Hallegraeff, sp. nov. The genus and two species are characterized by LM and EM of field samples and laboratory cultures as well as large subunit rDNA sequences and HPLC Pigment analyses of several cultured strains. The new Takayama species have sigmoid apical grooves and contain fucoxanthin and its derivatives as the main Accessory Pigments. Takayama tasmanica is similar to the previously described species Gymnodinium pulchellum Larsen, Gyrodinium acrotrochum Larsen, and G. cladochroma Larsen in its external morphology but differs from these in having two ventral pores, a large horseshoe-shaped nucleus, and a central pyrenoid with radiating chloroplasts that pass through the nucleus. It contains gyroxanthin-diester and a gyroxanthin-like Accessory Pigment, both of which are missing in T. helix. Takayama helix has an apical groove that is nearly straight while still being clearly inflected. A ventral pore or slit is present. It has numerous peripheral, strap shaped, and spiraling chloroplasts with individual pyrenoids and a solid ellipsoidal nucleus. The genus Takayama has close affinities to the genera Karenia and Karlodinium.
