• ALGAE
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• v.36 no.2
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• pp.73-90
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• 2021

Relative to the large number of photosynthetic dinoflagellate species, only a select few possess proteinaceous, carotenoid-rich eyespots which have been demonstrated in other algae to act in phototactic responses. The proteins comprising the different categories of dinoflagellate eyespots are positioned in or near the peridinin-containing photosynthetic plastid membranes which are composed primarily of two galactolipids, mono- and digalactosyldiacylglycerol (MGDG and DGDG). Within eyespot-containing dinoflagellates, this arrangement occurs mostly in those with secondary plastids, although some dinoflagellates with tertiary plastids of diatom origin are known to possess eyespots. We here provide an examination of the MGDG and DGDG composition of eyespot-containing dinoflagellates with secondary, peridinin-containing plastids and tertiary plastids of diatom origin to address the fundamental question of whether eyespots and their component proteins and carotenoids are associated with alterations in galactolipid composition when compared to eyespot-lacking photosynthetic dinoflagellates. This is an important question because the dinoflagellate eyespot-plastid membrane system can be considered a more complicated and evolved state of plastid development. Included in this examination are data on the previously unexamined peridinin- and type A eyespot-containing dinoflagellate Margalefidinium polykrikoides, and the type D eyespot-containing, aberrant plastid "dinotom" Durinskia baltica. In addition, we have reviewed the galactolipid composition of algae from the Chlorophyceae, Cryptophyceae, and Euglenophyceae as a comparison to determine if algal classes apart from the Dinophyceae contain altered galactolipids in association with eyespots. We conclude that the presence of an eyespot in dinoflagellates and other algae is not associated with noticeable changes in galactolipid composition.

• Journal of Environmental Science International
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• v.19 no.5
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• pp.607-615
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• 2010

We investigated the temporal variations of heterotrophic dinoflagellates (hereafter HDNF) and photosynthetic dinoflagellates (hereafter PDNF) from 14 June to 4 September 2003 at a single station in Jangmok Bay. We took water samples 47 times from 2 depths (surface and bottom layers) at hide tide. A total of 63 species were encountered and in general the most abundant genera were Prorocentrum and Protoperidinium. The abundance of PDNF and HDNF was in the range of $0.04{\sim}55.8{\times}10^4$ cells/L and in the range of $0.01{\sim}4.35{\times}10^4$ cells/L, respectively. The mean abundance of PDNF was approximately 7 times higher than that of HDNF, and was higher in the surface layer where has enough irradiance for photosynthesis than in the bottom layer. The total dinoflagellate abundance was higher in the NLP (nitrogen limitation period) than in the SLP (silicate limitation period), and the abundance in the hypoxic conditions was similar to that in the normal conditions. The Shannon-Weaver species diversity index were slightly higher in the bottom layer, the SLP and the hypoxic conditions. The PDNF abundance were correlated with temperature, DO, total inorganic nitrogen and phosphate in the whole water column, and the HDNF abundance was significantly correlated with temperature, salinity and DO. This study shows that the dinoflagellate abundance might be affected by abiotic factors such as irradiance, temperature, salinity, DO and the concentrations of inorganic nutrients, and provides baseline information for further studies on plankton dynamics in Jangmok Bay.

• Journal of the korean society of oceanography
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• v.37 no.4
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• pp.201-211
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• 2002

We investigated the abundance and biomass of dinoflagellates and factors controlling their abundance in marine planktonic ecosystems in Korean coastal waters. The abundance of photosynthetic (PDNF) and heterotrophic dinoflagellates (HDNF) was in the range of 0.7${\times}$10$^2$ cells/1-14.0${\times}$10$^6$ cells/1 and in the range of 3.0${\times}$10$^2$ cells/1-6.47${\times}$10$^5$ cells/I, respectively. Their biomass was 0.5${\times}$10$^{-1}$-2.56${\times}$10$^4$ ${\mu}gC/I$ and 2.0${\times}$10$^{-1}$-1.5${\times}$10$^{2}$ ${\mu}gC/I$, respectively. In order to find factors controlling their abundance, stepwise regression and best subsets regression analyses were used. We found that during the summer the most important factors controlling PDNF abundance are DO, P, N and S (abiotic factors), and for HDNF, the abundance of zooplankton, ciliates and HF (biotic factors), and that high turbidity may effect the distribution of dinoflagellate species.

• Ocean and Polar Research
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• v.34 no.2
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• pp.111-123
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• 2012

To understand the phytoplankton community in the eastern part of the Yellow Sea (EYS), in the summer, field survey was conducted at 25 stations in June 2009, and water samples were analyzed using a epifluorescence microscopy, flow cytometry and HPLC method. The EYS could be divided into four areas by a cluster analysis, using phytoplankton group abundances: coastal mixing area, Anma-do area, transition water, and the central Yellow Sea. In the coastal mixing area, water column was well mixed vertically, and phytoplankton was dominated by diatoms, chrysophytes, dinoflagellates and nanoflagellates, showing high abundance ($>10^5\;cells\;l^{-1}$). In Anma-do coastal waters characterized by high dominance of dinoflagellates, high phytoplankton abundance and biomass separated from other coastal mixing area. The southeastern upwelling area was expanded from Jin-do to Heuksan-do, by a tidal mixing and coastal upwelling in the southern area of Manjae-do, and phytoplankton was dominated by benthic diatoms, nanoflagellates and Synechococcus group in this area. Phytoplankton abundance and biomass dominated by pico- and nanophytoplankton were low values in the transition waters and the central Yellow Sea. In the surface of the central Yellow Sea, high dominance of photosynthetic pigments, 19'-hexanoyloxyfucoxanthin and zeaxanthin implies that haptophytes and cyanobacteria could be the dominant group during the summer. These results indicate that the phytoplankton communities in the EYS were significantly affected by the formation of tidal front, thermal stratification, and coastal upwelling showing the differences of physical and chemical characteristics during the summer.

• Applied Biological Chemistry
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• v.23 no.1
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• pp.73-83
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• 1980

The light harvesting pigment proteins of dinoflagellates exhibit essentially 100% efficient energy transfer from carotenoid (peridinin) to chlorophyll a within the antenna pigment complexes. The high efficiency of solar energy harvesing (particularly blue light) for photosynthesis in dinoflagellates is attributable to the unique molecular topography of peridinin and chlorophyll e within the protein crevice. The mechanisms of energy transfer from carotenoids to chlorophyll in higher plants have also been discussed in comparison with the dinoflagellate antenna pigment complexes. As an example of solar energy harvesting, particularly red light, for photosynthesis in algae, the molecular topography and energy transfer in the photosynthetic accessory pigment protein, Chroomonas phycocyanin, have also been discussed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.3
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• pp.215-225
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• 2004

Biomass and community composition of microphytobenthos in the Saemankeum tidal flat were studied by HPLC analysis of the photosynthetic pigments from November 2001 to November 2002. The environmental factors of sediment were also investigated to examine the relationship between microphytobenthos biomass and sedimentary environments. The detected photosynthetic pigments of microphytobenthos were chlorophyll a, b, c, fucoxanthin, 19'-hexanoyloxyfucoxanthin, violaxanthin, diadinoxanthin, alloxanthin, diatoxanthin, zeaxanthin+lutein, peridinin and beta-carotene. Pheophytin a, the degradation product of chlorophyll a, was also detected. The results of pigmen analysis suggest the presence of diatom (fucoxanthin), euglenophytes (chlorophyll b), chlorophytes (chlorophyll b + lutein), cyanobacteria (zeaxanthin), cryptophytes (alloxanthin), chrysophytes (fucoxanthin + violaxanthin), prymnesiophytes (19'-hexanoyloxyfucoxanthin) and dinoflagellates (peridinin). Chlorophyll a concentration in the top 0.5 cm of sediment was in the range of $0.24\;mg{\cdot}m\^{-2}\;-32.11\;mg{\cdot}m\^{-2}$ in the study area. The increase of chlorophyll a concentration in the spring indicates the occurrence of a microphytobenthic bloom. In the summer, there was a sharp decrease of the chlorophyll a concentration which was probably due to high grazing activity by macrobenthos. The annual mean chlorophyll a concentration in the study area was low compared to that in most of other tidal flat areas probably due to active resuspension of microphytobenthos and high grazing activity by macrobenthos. There was no clear relationship between microphytobenthos biomass and sedimentary environments because of a large variety of physical, chemical and biological factors, Pigment analysis indicated that while diatoms were dominated in the microphytobenthic community of the Geojon tidal flat, euglenophytes and/or chlorophytes coexisted with diatoms in the Mangyung River tidal flat.

• Journal of Environmental Science International
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• v.17 no.10
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• pp.1155-1167
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• 2008

Chlorophyll a (chl a) has been used as an indicator for phytoplankton biomass in pelagic ecosystems due to the relative ease of measurement and selectivity for autotrophs in mixed plankton assemblages. However, the use of chi a as an indicator for phytoplankton biomass is restricted due to its inability to resolve taxonomic differences of phytoplankton and the highly variable relationship of chi a with phytoplankton. Here, we describe the analysis of High-Performance Liquid Chromatography (HPLC) photosynthetic pigment data using CHEMTAX, which is a matrix factorization program that uses chemical taxonomic indices (phytoplankton carotenoids) to quantify the abundance of phytoplankton groups. Compared to direct microscopic counting that can distinguish species within broad groups, the resolution of taxonomic groups by CHEMTAX is generally coarse. It can only distinguish between diatoms, dinoflagellates, cryptophytes, cyanobacteria, chlorophytes, prasinophytes, and haptophytes. However, CHEMTAX analysis is much faster and less expensive than microscopic counting methods. HPLC pigment observations were taken in the spring, summer, fall, and winter in$ 2005\sim2006$ within Gamak Bay, South Korea. CHEMTAX results revealed that diatoms were the dominant taxonomic group in Gamak Bay. In inner Gamak Bay, the ratio between diatoms and cryptophytes was $75\sim80%$, and the ratio between dinoflagellates and cryptophytes was $10\sim15%$. In outer Gamak Bay, the ratio between diatoms and cryptophytes was $85\sim90%$, and the ratio between dinflagellates and cryptophytes was only $1\sim5%$. The population structure was seasonal. Relative diatom populations were less in the summer than the winter season.

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.1094-1099
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• 2005

Photosynthetic dinoflagellates contain a water-soluble, light-harvesting antenna called the peridinin-chlorophyll-protein (PCP) complex, which has an apoprotein with no sequence similarity to other known proteins. There are two forms of PCP apoproteins; the 15-kDa short form and the 32- to 35­kDa long form. The present study describes the PCP protein and its cDNA from Alexandrium tamarense. A cDNA library was constructed from mRNA isolated from A. tamarense. The complete PCP cDNA was generated by reverse-transcription coupled to polymerase chain reaction (RT-PCR), together with rapid-amplification of cDNA ends (RACE). The A. tamarense PCP cDNA encoded a 55-amino acid signal peptide and a 313-amino acid mature protein with a calculated mass of 32 kDa, which corresponded to that of the long form of PCP. Phylogenetic analysis indicated that the sequence of A. tamarense PCP did not cluster with the short-form PCPs, to which it was only about $55\%$ identical, but which were $79-83\%$ identical to other long-form PCPs. The deduced amino acid sequence of A. tamarense PCP contains an internal duplication, which suggests the possibility that long-form PCPs arose by gene duplication or by the fusion of genes encoding the short form. The abundance of PCP mRNA changed substantially in response to different light conditions, indicating the possible existence of a photo-acclimation response in A. tamarense.

• Ocean and Polar Research
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• v.32 no.3
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• pp.321-329
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• 2010

Photosynthetic pigments, nutrients, and hydrographic variables were examined in order to elucidate the spatio-temporal variation of water column structure and its effect on phytoplankton community structure in the western channel of the Korea Strait in fall 2006 and spring 2007. High phytoplankton biomass in the spring was associated with high salinity, implying that nutrients were not supplied by coastal waters or the Yangtze-River Diluted water (YRDW) with low salinity. Expansion of the Korea Strait Bottom Cold Water (KSBCW) and a cold eddy observed during the spring season might enhance the nutrient supply from the subsurface layer to the euphotic zone. Chemotaxonomic examination showed that diatoms accounted for 60-70% of total biomass, followed by dinoflagellates. Nutrient supply by physical phenomena such as the expansion of the KSBCW and the occurrence of a cold eddy appears to be the controlling factors of phytoplankton community composition in the Korea Strait. Further study is needed to elucidate the mechanisms by which the KSBCW is expanded, and its role in phytoplankton dynamics.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.3
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• pp.181-194
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• 2002

Parasitism is a one-sided relationship between two organisms in which one benefits at the expense of the other. Parasitic dinoflagellates, particularly species of Amoebophrya, have long been thought to be a potential biological agent for controlling harmful algal bloom(HAB). Amoebophrya infections have been reported for over 40 species representing more than 24 dinoflagellate genera including a few toxic species. Parasitic dinoflagellates Amoebophrya spp. have a relatively simple life cycle consisting of an infective dispersal stage (dinospore), an intracellular growth stage(trophont), and an extracellular reproductive stage(vermiform). Biology of dinospores such as infectivity, survival, and ability to successfully infect host cells differs among dinoflagellate host-parasite systems. There are growing reports that Amoebophrya spp.(previously, collectively known as Amoebophrya ceratii) exhibit the strong host specificity and would be a species complex composed of several host-specific taxa, based on the marked differences in host-parasite biology, cross infection, and molecular genetic data. Dinoflagellates become reproductively incompetent and are eventually killed by the parasite once infected. During the infection cycle of the parasite, the infected host exhibits ecophysiologically different patterns from those of uninfected host in various ways. Photosynthetic performance in autotrophic dinoflagellates can be significantly altered following infection by parasitic dinoflagellate Amoebophrya, with the magnitude of the effects over the infection cycle of the parasite depending on the site of infection. Parasitism by the parasitic dinoflagellate Amoebophrya could have significant impacts on host behavior such as diel vertical migration. Parasitic dinoflagellates may not only stimulate rapid cycling of dissolved organic materials and/or trace metals but also would repackage the relatively large sized host biomass into a number of smaller dinospores, thereby leading to better retention of host's material and energy within the microbial loop. To better understand the roles of parasites in plankton ecology and harmful algal dynamics, further research on a variety of dinoflagellate host-parasite systems is needed.