• Korean Journal of Environmental Biology
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• v.35 no.3
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• pp.273-288
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• 2017

An investigation focusing on the unrecorded and taxonomically undescribed indigenous has been done since 2006. Samples were collected from various sites in the coastal and offshore waters of Korea as well as around Jeju Island. Since 2008, 16 unrecorded species belonging to the family Gymnodiniaceae have been found. The species were as follows: Amphidinium thermaeum (2015), Cochlodinium convolutum (2015), C. strangulatum (2015), Gymnodinium abbreviatum (valid name: G. gracile), G. arenicola (2015), G. gracile (2015), G. dorsalisulcum (2015), G. microreticulatum (2014), G. micrum (2016) (valid name: Karlodinium micrum), G. pyrenoidosum (2016), G. simplex (2015), G. veneficum (2016) (valid name: Karlodinium veneficum), Gyrodinium aureum (2015), G. fusiforme (2015), G. dominans (2014), and Nusuttodinium latum (2016) (valid name: Amphidinium latum). (The numbers in parentheses refer to the year that the species was found). These species were newly recorded in Korean waters in this study.

• Journal of Life Science
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• v.17 no.11
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• pp.1453-1463
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• 2007

This study presents a molecular phylogenetic analysis of the harmful dinoflagellate Cochlodinium polykrikoides, by use of partial sequence of small subunit (SSU) rRNA gene from most of the major taxa(24 species) in dinoflagellates. The class Dinophyceae clade formed a strong monophyletic relationship with C. polykrikoides and several taxa. On the basis of deeper nodes, the phylogenetic relationships placed C. polykrikoides closer to the order Prorocentrales rather than to the order Gymnodiniales, which was supported by a strong bootstrap value (100%) in the analyses of Neighbor-Joining and Parsimony methods. There is strong support for C. polykrikoides being placed in the same branch as Gymnodiniaceae and being connected in a clade with Prororcentrum micans among Prorocentrales. Morphological data show that C. polykrikoides is well associated with the genus Gyrodinium; however, this species is genetically closer to Gymnodinium than to Gyrodinium. The placement of C. polykrikoides always formed an independent branch separated from other dinoflagellates. In conclusion, planktonic P. micans plays an important role as an ancestor of Gymnodinium, whereas C. polykrikoides appears to be used an intermediate position between P. micans and Gymnodinium based on evolution.

• Korean Journal of Environmental Biology
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• v.36 no.3
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• pp.260-270
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• 2018

A study describing unrecorded and taxonomically undescribed indigenous species is in progress since 2006. Samples were collected from many sites in coastal waters and offshore of Korea as well as from Jeju Island. Since 2008, we have found ten unrecorded species of four genera belonging to family Dinophysaceae, Gonyaulacaceae, Gymnodiniaceae, and Heterocapsaceae. The species are as follows, Dinophysis elongata (2016 winter), D. nasuta (2016 winter), Gonyaulax alaskensis (2016 winter), G. diegensis (2017), G. monospina (2008), Amphidinium flagellans(2017), Heterocapsa circularisquama (2017), H. horiguchii (2017), H. lanceolata (2017), and H. pygmaea (2017) (note; The numbers in the parenthesis refer to the year in which the species was reported as unrecorded indigenous species by National Institute of Biological Resources, NIBR hereafter). Among them, seven species were described as newly recorded species in Korean waters, and three have been re-described in this study.

• ALGAE
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• v.35 no.3
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• pp.225-236
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• 2020

Gymnodinium smaydae is a newly described mixotrophic dinoflagellate that feeds on only Heterocapsa spp. and Scrippsiella acuminata among 19 tested algal prey. It is one of the fastest growing dinoflagellates when feeding, but does not grow well without prey. To investigate its spatial-temporal distributions in Korean waters, we quantified its abundance in water samples that were seasonally collected from 28 stations along the Korean Peninsula from April 2015 to October 2018, using quantitative real-time polymerase chain reactions. This dinoflagellate had a wide distribution, as reflected by the detection of G. smaydae cells at 23 of the sampling stations. However, this distribution had a strong seasonality; it was detected at 21 stations in the summer and only one station in winter. The abundance of G. smaydae was significantly and positively correlated with chlorophyll a concentration as well as with water temperature. However, there were no significant correlations between the abundance of G. smaydae and salinity, concentrations of nutrients, or dissolved oxygen concentration. During the study period, G. smaydae was present when water temperatures were 7.6-28.0℃, salinities were 9.6-34.1, concentrations of NO₃ were not detectable-106.0 μM, and concentrations of PO₄ were not detectable-3.4 μM. The highest abundance of G. smaydae was 18.5 cells mL^-1 in the coastal waters of Jinhae in July 2017 when the chlorophyll a concentration was 127 mg m^-3 and water temperature was 23.8℃. Therefore, the spatial-temporal distribution of G. smaydae in Korean coastal waters may be affected by chlorophyll a concentration and water temperature.

• ALGAE
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• v.33 no.3
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• pp.279-290
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• 2018

Microalgae have been utilized in diverse industries including aquaculture. Among the microalgae, dinoflagellates are known to have various bioactive compounds, and thus the interest in their application to industry has increased. In order to test their potential as food materials for aquaculture animals, the crude protein contents and compositions of amino acids of six dinoflagellates Heterocapsa rotundata (family Heterocapsaceae), Ansanella granifera (Suessiaceae), Alexandrium andersonii (Ostreopsidaceae), Takayama tasmanica (Brachidiniaceae), Takayama helix, and Gymnodinium smaydae (Gymnodiniaceae) belonging to diverse families were analyzed. The percentage of the amount of the crude protein relative to dry weight of T. tasmanica was the highest (65%) and that of A. andersonii was the lowest (26%). However, the highest percentage of total detected amino acids in crude protein was found in A. andersonii (98.2%). In all six dinoflagellates, glutamic acid was the most dominant amino acid in crude protein. However, the second main amino acid was aspartic acid for H. rotundata, A. granifera, T. helix, and G. smaydae, but were arginine and leucine for A. andersonii and T. tasmanica, respectively. Furthermore, T. tasmanica and T. helix did not have taurine and gamma-aminobutyric acid, whereas the other dinoflagellates possessed them. The percentages of essential amino acid contents of the dinoflagellates met the requirement levels for juvenile shrimps. In addition, the dinoflagellates were not toxic to the brine shrimp Artemia salina. Compared with the other microalgae reported so far, H. rotundata and A. andersonii can be used for arginine-rich diets, T. tasmanica for valine and leucine-rich diets, A. granifera for histidine-rich diets, T. helix for threonine-rich diets, and G. smaydae for lysine-rich diets. Therefore, based on their biochemical composition and toxicity to Artemia, the dinoflagellates could be used as essential amino acid sources for cultivating animals in the aquaculture industry.