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Duu-jong Lee - One of the best experts on this subject based on the ideXlab platform.
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inactivation of Amphidinium sp in ballast waters using uv ag tio2 o3 advanced oxidation treatment
Bioresource Technology, 2011Co-Authors: Hong You, Ran Zhang, Chuan Chen, Duu-jong LeeAbstract:Abstract Ballast water poses a biological threat to the world’s waterways by transferring aquatic species from one body of water to another. This study investigates the use of combined ultraviolet (UV)/Ag-TiO 2 + ozone (O 3 ) processes for treating ballast water using Amphidinium sp. as an indicator microorganism. Sufficient Amphidinium sp. cells in ballast waters can be inactivated using O 3 alone, UV irradiation alone (with or without an Ag-TiO 2 coating), and combined treatments. For the low inactivation ratio ( 2 + O 3 treatment produced excess hydroxyl radicals and total residual oxidants (TROs), and readily damaged cell membranes to release intracellular substances. The comparison tests revealed that the combined treatments synergistically inactivate Escherichia coli in ballast waters. However, the combined process did not synergistically inactivate Amphidinium sp. cells. Inactivating different aqua species in ballast waters needs distinct treatment methods and dosages.
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Inactivation of Amphidinium sp. in ballast waters using UV/Ag-TiO2+O3 advanced oxidation treatment.
Bioresource technology, 2011Co-Authors: Hong You, Ran Zhang, Chuan Chen, Duu-jong LeeAbstract:Abstract Ballast water poses a biological threat to the world’s waterways by transferring aquatic species from one body of water to another. This study investigates the use of combined ultraviolet (UV)/Ag-TiO 2 + ozone (O 3 ) processes for treating ballast water using Amphidinium sp. as an indicator microorganism. Sufficient Amphidinium sp. cells in ballast waters can be inactivated using O 3 alone, UV irradiation alone (with or without an Ag-TiO 2 coating), and combined treatments. For the low inactivation ratio ( 2 + O 3 treatment produced excess hydroxyl radicals and total residual oxidants (TROs), and readily damaged cell membranes to release intracellular substances. The comparison tests revealed that the combined treatments synergistically inactivate Escherichia coli in ballast waters. However, the combined process did not synergistically inactivate Amphidinium sp. cells. Inactivating different aqua species in ballast waters needs distinct treatment methods and dosages.
Jun'ichi Kobayashi - One of the best experts on this subject based on the ideXlab platform.
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Total synthesis of amphidinolide Q.
Organic letters, 2009Co-Authors: Masahiro Hangyou, Haruaki Ishiyama, Yohei Takahashi, Jun'ichi KobayashiAbstract:Asymmetric synthesis of amphidinolide Q, a cytotoxic macrolide from the cultured dinoflagellate Amphidinium sp., has been accomplished with Julia coupling, Myers alkylation, and Yamaguchi lactonization. The absolute configuration of amphidinolide Q was confirmed to be 1 from comparison of the NMR data and [α]D values of synthetic and natural amphidinolide Q.
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Amphidinolides and Its Related Macrolides from Marine Dinoflagellates
The Journal of Antibiotics, 2008Co-Authors: Jun'ichi KobayashiAbstract:This review covers the recent results described in our publications on several new cytotoxic macrolides isolated from dinoflagellates of the genus Amphidinium in addition to an overview of the isolation, structure elucidation, synthesis, biosynthesis, and bioactivity of a series of cytotoxic macrolides, named amphidinolides, reported so far.
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iriomoteolide 3a a cytotoxic 15 membered macrolide from a marine dinoflagellate Amphidinium species
Journal of Organic Chemistry, 2008Co-Authors: Keiko Oguchi, Jun'ichi Kobayashi, Eri Fukushi, Jun Kawabata, Atsunori Masuda, Masashi Tsuda, Rie Iwamoto, Tomoko Ozawa, Yumiko Okamoto, Yoshiaki KitayaAbstract:A 15-membered macrolide, iriomoteolide-3a (1), with an allyl epoxide has been isolated from a marine benthic dinoflagellate Amphidinium sp. (strain HYA024), and the structure was assigned by detailed analyses of 2D NMR data. Relative and absolute configurations were elucidated on the basis of conformational studies of 1 and its acetonide (2) and modified Mosher's method of 1, respectively. Iriomoteolide-3a (1) and the acetonide (2) exhibited potently cytotoxic activity against antitumor cells.
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Amphidinolides B6 and B7, cytotoxic macrolides from a symbiotic dinoflagellate Amphidinium species.
Journal of natural products, 2007Co-Authors: Keiko Oguchi, Jun'ichi Kobayashi, Masashi Tsuda, Rie Iwamoto, Tomoko Ozawa, Yumiko Okamoto, Taeko Endo, Atsunori MasudaAbstract:Two 26-membered macrolides, amphidinolides B6 (2) and B7 (1), have been isolated from a marine symbiotic dinoflagellate Amphidinium sp., and the structures were elucidated on the basis of detailed analyses of 2D NMR data. The relative and absolute configurations for 1 and 2 were assigned by comparison of NMR data and CD data with those of known amphidinolides.
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iriomoteolide 1a a potent cytotoxic 20 membered macrolide from a benthic dinoflagellate Amphidinium species
Journal of Organic Chemistry, 2007Co-Authors: Masashi Tsuda, Jun'ichi Kobayashi, Eri Fukushi, Jun Kawabata, Atsunori Masuda, Rie Iwamoto, Tomoko Ozawa, Keiko Oguchi, Yumiko Okamoto, Yoshiaki KitayaAbstract:A potent cytotoxic 20-membered macrolide, iriomoteolide-1a (1), has been isolated from a benthic dinoflagellate Amphidinium sp. (strain HYA024), and the structure was elucidated on the basis of detailed analyses of 2-D NMR data. The relative and absolute stereochemistries were assigned by the combination of conformational analyses using NMR data and modified Mosher's method of 1.
Shauna A. Murray - One of the best experts on this subject based on the ideXlab platform.
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a fish kill associated with a bloom of Amphidinium carterae in a coastal lagoon in sydney australia
Harmful Algae, 2015Co-Authors: Shauna A. Murray, Gurjeet S Kohli, Hazel Farrell, Zoe B Spiers, Allen R Place, Juan Jose Dorantesaranda, Jason RuszczykAbstract:We report on a dense bloom (∼1.80 × 105 cells mL−1) of the marine dinoflagellate species Amphidinium carterae (Genotype 2) in a shallow, small intermittently open coastal lagoon in south eastern Australia. This bloom co-occurred with the deaths of >300 individuals of three different species of fish. The opening of the lagoon to the ocean, as well as localized high nutrient levels, preceded the observations of very high cell numbers. A. carterae is usually benthic and sediment-dwelling, but temporarily became abundant throughout the water column in this shallow (<2 m) sandy habitat. Histopathological results showed that the Anguilla reinhardtii individuals examined had damage to epithelial and gill epithelial cells. An analysis of the bloom water indicated the presence of a compound with a retention time and UV spectra similar to Luteophanol A, a compound known from a strain of Amphidinium. Assays with a fish gill cell line were conducted using a purified compound from cells concentrated from the bloom, and was found to cause a loss of 87% in cell viability in 6 h. The fish deaths were likely due to the low dissolved oxygen levels in the water and/or the presence of Luteophanol A-like compounds released during the bloom.
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MORPHOLOGY AND MOLECULAR PHYLOGENY OF ANKISTRODINIUM GEN. NOV. (DINOPHYCEAE), A NEW GENUS OF MARINE SAND-DWELLING DINOFLAGELLATES FORMERLY CLASSIFIED WITHIN Amphidinium(1).
Journal of phycology, 2012Co-Authors: Mona Hoppenrath, Shauna A. Murray, Sarah F. Sparmann, Brian S. LeanderAbstract:The classical athecate dinoflagellate genera (Amphidinium, Gymnodinium, Gyrodinium) have long been recognized to be polyphyletic. Amphidinium sensu lato is the most diverse of all marine benthic dinoflagellate genera; however, following the redefinition of this genus ∼100 species remain now of uncertain or unknown generic affiliation. In an effort to improve our taxonomic and phylogenetic understanding of one of these species, namely Amphidinium semilunatum, we re-investigated organisms from several distant sites around the world using light and scanning electron microscopy and molecular phylogenetic methods. Our results enabled us to describe this species within a new heterotrophic genus, Ankistrodinium. Cells of A. semilunatum were strongly laterally flattened, rounded-quadrangular to oval in lateral view, and possessed a small asymmetrical epicone. The sulcus was wide and characteristically deeply incised on the hypocone running around the antapex and reaching the dorsal side. The straight acrobase with hook-shaped end started at the sulcal extension and continued onto the epicone. The molecular phylogenetic results clearly showed that A. semilunatum is a distinct taxon and is only distantly related to species within the genus Amphidinium sensu stricto. The nearest sister group to Ankistrodinium could not be reliably determined.
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Genetic diversity, morphological uniformity and polyketide production in dinoflagellates (Amphidinium, Dinoflagellata).
PloS one, 2012Co-Authors: Shauna A. Murray, Tamsyn J. Garby, Mona Hoppenrath, Brett A. NeilanAbstract:Dinoflagellates are an intriguing group of eukaryotes, showing many unusual morphological and genetic features. Some groups of dinoflagellates are morphologically highly uniform, despite indications of genetic diversity. The species Amphidinium carterae is abundant and cosmopolitan in marine environments, grows easily in culture, and has therefore been used as a ‘model’ dinoflagellate in research into dinoflagellate genetics, polyketide production and photosynthesis. We have investigated the diversity of ‘cryptic’ species of Amphidinium that are morphologically similar to A. carterae, including the very similar species Amphidinium massartii, based on light and electron microscopy, two nuclear gene regions (LSU rDNA and ITS rDNA) and one mitochondrial gene region (cytochrome b). We found that six genetically distinct cryptic species (clades) exist within the species A. massartii and four within A. carterae, and that these clades differ from one another in molecular sequences at levels comparable to other dinoflagellate species, genera or even families. Using primers based on an alignment of alveolate ketosynthase sequences, we isolated partial ketosynthase genes from several Amphidinium species. We compared these genes to known dinoflagellate ketosynthase genes and investigated the evolution and diversity of the strains of Amphidinium that produce them.
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a new genus of athecate interstitial dinoflagellates togula gen nov previously encompassed within Amphidinium sensu lato inferred from light and electron microscopy and phylogenetic analyses of partial large subunit ribosomal dna sequences
Phycological Research, 2004Co-Authors: Mårten Flø Jørgensen, Shauna A. Murray, Niels DaugbjergAbstract:SUMMARY The recent emendation of Amphidinium (Dinophyc-eae), which now only consists of species with minute left-deflected epicone, has left more than 100 species without a clear generic affiliation. In the present study, a strain identified as one of the species with a divergent epicone type, Amphidinium britannicum (Herdman) Lebour, and six strains resembling A. britannicum but smaller in size were examined by light, scanning and transmission electron microscopy and by sequence analyses of nuclear-encoded partial large subunit ribosomal DNA to establish their phylog-eny. Amphidinium britannicum was not closely related to other genera included in the molecular phylogenetic analyses, but formed a highly supported clade in Bayesian analysis together with the six small-sized strains. The six strains also formed a highly supported clade, consisting of two closely related, albeit distinct, clades. Light and scanning electron microscopy did not reveal significant differences between the vegetative motile cells; however, cells about to undergo mitosis developed longitudinal grooves on the hypocone in one of the clades but not in the other. Both clades differed substantially from A. britannicum in partial large subunit ribosomal DNA as well as in size and shape. Based on morphological similarity and partial large subunit ribosomal DNA evidence, we erect the new genus, Togula gen. nov. with the emended type species Togula britannica (Herdman) comb. nov. Based on differences in division pattern and partial large subunit ribosomal DNA gene divergence we further describe the species Togula compacta (Herdman) comb. nov. and Togula jolla sp. nov.
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Amphidinium revisited i redefinition of Amphidinium dinophyceae based on cladistic and molecular phylogenetic analyses
Journal of Phycology, 2004Co-Authors: Mårten Flø Jørgensen, Shauna A. Murray, Niels DaugbjergAbstract:Members of Amphidinium Claparede and Lachmann constitute a major part of sand-dwelling benthic dinoflagellates worldwide. The genus is traditionally defined by its small epicone size, not exceeding one third of the total cell length. It has long been suspected that this functional definition does not reflect phylogeny, yet the problem of identifying the type species A. operculatum and closely related species has until now hindered attempts to redefine the genus. In this study 12 Amphidinium species were examined using phylogenetic analyses based on nuclear-encoded, partial, large subunit (LSU) rDNA, with a further six Amphidinium species being included in a morphological cladistic analysis. The species selected represented taxa with a range of morphological dissimilar epicone forms. Both cladistic analysis and analyses based on partial LSU rDNA revealed that Amphidinium species with minute left-deflected epicones formed a monophyletic clade that included the type species. Amphidinium species with other epicone types were found to be unrelated to this clade. The type species A. operculatum was identified based on general cell shape and size, position of a dark organelle previously defined as a stigma, and origin of the sulcus. The description of A. elegans by Grell and Wohlfarth-Bottermann was found to be identical to it. A species fitting the original description of A. operculatum was cultured and included in the analyses. Based on cladistic and molecular analyses, it grouped together with all other species with minute left-deflected epicones, and this group constitutes the true genus Amphidinium sensu stricto. An emendation of the genus definition is presented.
Senjie Lin - One of the best experts on this subject based on the ideXlab platform.
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mrna editing and spliced leader rna trans splicing groups oxyrrhis noctiluca heterocapsa and Amphidinium as basal lineages of dinoflagellates1
Journal of Phycology, 2008Co-Authors: Huan Zhang, Senjie LinAbstract:Identification of novel dinoflagellate taxa through molecular analysis is hindered by lack of well-defined basal lineages. To address this issue, we attempted to reassess the phylogenetic status of Oxyrrhis marina Dujard. as well as other potentially basal taxa. The analysis was based on two newly established premises: (1) editing density of mitochondrial cob and cox1 mRNA increases from basal to later diverging lineages; (2) nuclear-encoded mRNA in dinoflagellates is trans-spliced to receive a 22 bp spliced leader (SL) at the 5′-end. We analyzed these two genetic traits in O. marina, Noctiluca scintillans (Macartney) Kof. et Swezy, Heterocapsa triquetra (Ehrenb.) F. Stein, H. rotundata (Lohmann) Ge. Hansen, Amphidinium carterae Hulburt, and A. operculatum Clap. et J. Lachm. Surprisingly, no editing was detected in cob and cox1 mRNAs in these lineages, except for a small number of editing events in Amphidinium. However, nuclear-encoded mRNAs in these species contained the SL sequence at the 5′-end, indicative of SL RNA trans-splicing. These findings, together with the recent cob-cox1-18S rRNA three-gene phylogeny, suggest the following: (1) O. marina is a basal dinoflagellate; (2) Heterocapsa, Amphidinium, and Noctiluca likely are also early diverging lineages of dinoflagellates, and the position of Heterocapsa is inconsistent with literature and needs further investigation; and (3) the presence of the 22 bp SL and mitochondrial (mt) mRNA editing can be considered a landmark of dinoflagellate splits.
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mRNA EDITING AND SPLICED‐LEADER RNA TRANS‐SPLICING GROUPS OXYRRHIS, NOCTILUCA, HETEROCAPSA, AND Amphidinium AS BASAL LINEAGES OF DINOFLAGELLATES1
Journal of phycology, 2008Co-Authors: Huan Zhang, Senjie LinAbstract:Identification of novel dinoflagellate taxa through molecular analysis is hindered by lack of well-defined basal lineages. To address this issue, we attempted to reassess the phylogenetic status of Oxyrrhis marina Dujard. as well as other potentially basal taxa. The analysis was based on two newly established premises: (1) editing density of mitochondrial cob and cox1 mRNA increases from basal to later diverging lineages; (2) nuclear-encoded mRNA in dinoflagellates is trans-spliced to receive a 22 bp spliced leader (SL) at the 5′-end. We analyzed these two genetic traits in O. marina, Noctiluca scintillans (Macartney) Kof. et Swezy, Heterocapsa triquetra (Ehrenb.) F. Stein, H. rotundata (Lohmann) Ge. Hansen, Amphidinium carterae Hulburt, and A. operculatum Clap. et J. Lachm. Surprisingly, no editing was detected in cob and cox1 mRNAs in these lineages, except for a small number of editing events in Amphidinium. However, nuclear-encoded mRNAs in these species contained the SL sequence at the 5′-end, indicative of SL RNA trans-splicing. These findings, together with the recent cob-cox1-18S rRNA three-gene phylogeny, suggest the following: (1) O. marina is a basal dinoflagellate; (2) Heterocapsa, Amphidinium, and Noctiluca likely are also early diverging lineages of dinoflagellates, and the position of Heterocapsa is inconsistent with literature and needs further investigation; and (3) the presence of the 22 bp SL and mitochondrial (mt) mRNA editing can be considered a landmark of dinoflagellate splits.
Hong You - One of the best experts on this subject based on the ideXlab platform.
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inactivation of Amphidinium sp in ballast waters using uv ag tio2 o3 advanced oxidation treatment
Bioresource Technology, 2011Co-Authors: Hong You, Ran Zhang, Chuan Chen, Duu-jong LeeAbstract:Abstract Ballast water poses a biological threat to the world’s waterways by transferring aquatic species from one body of water to another. This study investigates the use of combined ultraviolet (UV)/Ag-TiO 2 + ozone (O 3 ) processes for treating ballast water using Amphidinium sp. as an indicator microorganism. Sufficient Amphidinium sp. cells in ballast waters can be inactivated using O 3 alone, UV irradiation alone (with or without an Ag-TiO 2 coating), and combined treatments. For the low inactivation ratio ( 2 + O 3 treatment produced excess hydroxyl radicals and total residual oxidants (TROs), and readily damaged cell membranes to release intracellular substances. The comparison tests revealed that the combined treatments synergistically inactivate Escherichia coli in ballast waters. However, the combined process did not synergistically inactivate Amphidinium sp. cells. Inactivating different aqua species in ballast waters needs distinct treatment methods and dosages.
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Inactivation of Amphidinium sp. in ballast waters using UV/Ag-TiO2+O3 advanced oxidation treatment.
Bioresource technology, 2011Co-Authors: Hong You, Ran Zhang, Chuan Chen, Duu-jong LeeAbstract:Abstract Ballast water poses a biological threat to the world’s waterways by transferring aquatic species from one body of water to another. This study investigates the use of combined ultraviolet (UV)/Ag-TiO 2 + ozone (O 3 ) processes for treating ballast water using Amphidinium sp. as an indicator microorganism. Sufficient Amphidinium sp. cells in ballast waters can be inactivated using O 3 alone, UV irradiation alone (with or without an Ag-TiO 2 coating), and combined treatments. For the low inactivation ratio ( 2 + O 3 treatment produced excess hydroxyl radicals and total residual oxidants (TROs), and readily damaged cell membranes to release intracellular substances. The comparison tests revealed that the combined treatments synergistically inactivate Escherichia coli in ballast waters. However, the combined process did not synergistically inactivate Amphidinium sp. cells. Inactivating different aqua species in ballast waters needs distinct treatment methods and dosages.
