• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.15 no.1
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• pp.1-7
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• 2010

We were successfully reared young marine ornamental larva fish in a unique process of microalgae blooming culture tank. The marine fish larva was grown and survived in this method. Generally, we called this method as natural mixed culture. Observed planktonic microalgae were 34 species with 19 diatoms (Detonula pumila, Nitzschia sp., Fragilaria oceanica, Chaetoceros curvisetus, Stephanodiscus sp., Chaetoceros decipies, Chaetoceros sp., Thalassiosira rotula, Eucampia zodiacus, Diploneis splendica, Nitzschia longissima, Surirella cuneata, Asterionella glacialis, Nitzschia spp., Chaetoceros debile, Thalassionema nitzschioides, Nitzschia closterium, Skeletonema costatum and Licmophora sp.), 14 flagellates (Euglena, sp., Gonyaulax sp., Pyramimonas sp., Protoperidinium sp., Eutreptia sp., Parapedinella sp., unidentified micrc-flagellate, Gyrodinium sp., Scrippsiell trochoidea, Gymnodinium sanguineum, Chrysochromulina sp., Gymnodinium sp., Prorocentrum triestinum and Micromonas sp.) and 1 ciliate (Mesodinium rubrum) in this culture tank. Dominant microalgae were Chrysochromulina sp. during the larval rearing periods. Blooming condition maintained continuously and stably from 10 to 60 days in this microcosm.

• Journal of Microbiology and Biotechnology
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• v.10 no.3
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• pp.429-433
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• 2000

Giardia lamblia, a human pathogen causing outbreaks of diarrhea, recently became a focus of great concerns in the fields of both medical and environmental microbioloty. To develop the experimental tools to study giardiasis, encystation, one of the major processes in its life cycle, was reconstituted by inducing an axenic culture of a flagellated form of G. lamblia into a cyst from under high concentration of bile and alkaline pH condition. The successful induction was confirmed by Northern analysis of resulting increased expression of the CWPl gene encoding the cyst wall protein 1. An examination of the encystation process with SEM (scanning electron microscopy) and TEM (transmission electron microscopy) revealed that the trophozoite, a flagellate with a bilateral symmetry, was transformed to a cyst form with an oval-shape and defined filamentous wall. The encystation was found to cause a disappearance of the flagella and an invagination of the adhesive disc. An extensive formation of rER (rough endoplasmic reticulum) was observed after 24h of induction, indication an active synthesis and export of proteins during this process. The vital staining of the invitro-induced systs showed that most cysts maintained their viability.

• ALGAE
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• v.22 no.3
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• pp.235-240
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• 2007

The red tide-causing flagellate Chattonella anticfua can cause mass fish kills by their clogging in fish gills. Thisstudy examined the nutrient requirements of C. antiqua isolated from Korea. C. anticfua displayed maximum growthat the day five, followed by a decrease in cell density. Nitrate and nitrite were the preferred nitrogen sources, alonewith adenosine diphosphate for phosphorus compounds. In medium that contained ammonium, a significantdecrease in cell density was observed. Half-saturation constants, Ks, calculated from the maximum growth ratewere 4.94 U|M for NC>3 and 0.79 flM for P04. The growth of C. antiqua was not within the function of the N:P ratio (RU= 0.29). With an N:P ratio as low as 10, the increase in cell density was apparent, with a higher division rate. At lev-els above 50 fiM of NaNOg or 8 ;uM of NaHUPCU, the growth rates were somewhat decreased. Phosphate was thelimiting factor for C. antiqua growth since the starvation of phosphate had brought about a rapid decrease in celldensity in semi-continuous culture. Studies about the temporal modification of the efficiency of nitrate or phosphateuptake may be necessary to explain the bloom dynamics of C. antiaua.

• Korean Journal of Environmental Biology
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• v.38 no.2
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• pp.278-288
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• 2020

Rhodomonas salina is a phototrophic marine flagellate. We examined the ultrastructure of R. salina with particular attention to the flagellar apparatus by transmission electron microscopy and compared it with that of other cryptomonads reported previously. The major components of the flagellar apparatus in R. salina were a keeled rhizostyle (Rhs), a striated fibrous root(SR), a SR-associated microtubular root (SRm), a mitochondrion-associated lamella (ML), and three types of microtubular roots (9r, 4r, and 2r). The keeled Rhs originated near the proximal end of the dorsal basal body, passed near the nucleus and dissociated at the posterior end of the cell. The SR and SRm originated between two basal bodies and laterally extended to the right side of the cell. The ML originated between two basal bodies and extended to the left side of the cell. The 9r originated between the ventral basal body and the Rhs and extended toward the anterior dorsal lobe of the cell. The 4r originated near the 9r and extended toward the dorsal lobe with the 2r, which originated between two basal bodies. Here, the flagellar apparatus in R. salina is described, and the ultrastructure of the flagellar apparatus is compared among cryptomonad species.

• ALGAE
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• v.31 no.2
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• pp.117-128
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• 2016

Cryptomonas curvata Ehrenberg is a photosynthetic freshwater flagellate and the type species of the genus Cryptomonas. We examined the flagellar apparatus of cryptomorphic C. curvata by transmission electron microscopy. The major components of the flagellar apparatus are the non-keeled rhizostyle (Rhs), striated fibrous root (SR), striated fiber-associated microtubular root (SRm), mitochondrion-associated lamella (ML), and two types of microtubular roots (3r and 2r). The non-keeled Rhs originate at the ventral basal body and consist of two types of microtubule bands extending together into the middle of the cell. The SR and SRm extend parallel to the left side of the cell. The ML originates from the ventral basal body and is a plate-like fibrous structure associated with mitochondria. The 3r extends from the dorsal basal body toward the dorsal anterior of the cell. The 2r originates between the two basal bodies and extends shortly to the left of the cell. The overall configuration of the flagellar apparatus is most similar to that previously reported for C. pyrenoidifera. These results demonstrate that the features of the flagellar apparatus are useful for distinguishing closely related species and inferring phylogenetic relationships among taxa.

• Journal of Photoscience
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• v.9 no.2
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• pp.98-101
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• 2002

Euglena gracilis abruptly changes its swimming direction after a sudden increase or decrease in incident light intensity, that is, step-up or step-down photophobic responses, resulting in photoavoidance or photoaccumulation, respectively. To identify the photoreceptor molecules for these UV-A/blue-light type photobehaviors, we purified a flavoprotein from isolated putative photosencory organelles (PFBs) of Euglena. The purified flavoprotein, which noncovalently bound flavin adenine dinucleotide (FAD), seemed to be a heterotetramer of alpha- and beta-subunits. Predicted amino acid sequences of each of the subunits were similar to each other and contained two FAD-binding domains each followed by an adenylyl cyclase catalytic domain. The purified flavoprotein actually showed adenylyl cyclase activity, being drastically elevated by blue-light irradiation. Suppression of gene expression of the flavoprotein (Photoactivated Adenylyl Cyclase, PAC) by RNA interference (RNAi) caused loss of the step-up photophobic response, demonstrating that PAC actually mediates photoavoidance of Euglena.

• Journal of environmental and Sanitary engineering
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• v.22 no.4
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• pp.11-21
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• 2007

The recent investigation indicates that the kinetic constants for anionic ions were merely the result of ion exchange between the algae cell wall surface and the anionic ion. In this study, Zygnema sterile and Lepocinclism textra, floating flagellate alga as the dominant algae strains, were cultivated using HRABR(High Rate Algae Biomass Reactor) and the cultivation conditions were 24 hrs. and 12 hrs. irradiation and it was studied how this algal biomass acts on the biosorption mechanism of anionic N and P. Results are as follows : 1. Calculating the specific chl.-a growth rate using Michaelis-Menten model, the one of 24hrs. irradiation was about 55 times higher than the one of 12 hrs. irradiation 2. Calculating the specific chl.-a growth rate using Kuo model, the one of 24 hrs. irradiation was about 2.26 times higher than the one of 12 hrs. irradiation 3. Langmuir model can apply to the biosorption mechanism of anionic N and P in HRABP. 4. Regarding the chlorophyll-a concentration as unit weight of sorbent, the ion selectivity coefficients for N and P are as follows : $(NH_3-N)+(NO_3-N)$ in 24 hrs. irradiation ; 44.984 $PO_4-P$ in 24 hrs. irradiation ; 24.237 $(NH_3-N)+(NO_3-N)$ in 12 hrs. irradiation ; 1432.851 $PO_4-P$ in 12 hrs. irradiation ; 599.076

• Journal of the Korean Wood Science and Technology
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• v.46 no.6
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• pp.713-725
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• 2018

Lower termites require symbiotic microbes in their gut. The microbial communities in the termites must adapt to the termite temperature. Reticulitermes speratus KMT001 from Bukhan Mountain in Seoul may require a special symbiotic microorganisms for growth in low temperature Korean habitat. A metagenomics analysis showed a dramatic change in the symbiotic bacterial flora in the gut of R. speratus KMT001 in response to low temperatures of $4^{\circ}C$ or $10^{\circ}C$. Elusimicrobia, which are endosymbionts of flagellate protists, is the dominant phylum in the termite gut at ${\geq}15^{\circ}C$ but its population decreased drastically at low temperature. Four representative bacterial strains isolated from R. speratus KMT001 in a previous study produced maximum ${\beta}$-glucosidase levels within the temperature range of $10^{\circ}C-30^{\circ}C$. Elizabethkingia sp. BM10 produced ${\beta}$-glucosidase specifically at $10^{\circ}C$. This strain supported the existence of symbiotic bacteria for the low temperature habitat of the termite. This identified bacterium will be a resource for studying low temperature adaptation of termites, studying the gene expression at low temperatures, and developing an industrial cellulase at low temperature.

• Journal of Aquaculture
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• v.2 no.1
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• pp.43-51
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• 1989

Fatty acid contents were measured in the cultures of the flagellate green algae Dunaliella tertiolecta Butcher under different conditions of light intensity, duration of light, and temperature. Duration of light and temperature, in particular, affected the growth rate of D. tertiolecta. The maximun cell number reached $2.32{\times}10^6$ cells/ml. The division rate per day was 1.97 in the exponential phase. The analysis of fatty acids obtained from various conditions showed that the lipid mainly contained C16, C18:3$\omega$3 fatty acids and there was no significant level of polyunsaturated fatty acids such as EPA and DHA. Polyene fatty acid increased with decreasing temperature and light intensity did not influence on fatty acid composition. The increasing duration of light enhanced the growth of D. tertiolecta, whereas polyene($\omega$3) slightly increased with decreasing the light period.

• ALGAE
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• v.28 no.4
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• pp.331-341
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• 2013

Rhinomonas reticulata var. atrorosea G. Novarino is a photosynthetic marine flagellate that is known to have typical characteristics of cryptomonads. We examined the flagellar apparatus of R. reticulata var. atrorosea by transmission electron microscopy. The major components of the flagellar apparatus of R. reticulata var. atrorosea consisted of four types of microtubular roots (1r, 2r, 3r, and mr), a non-keeled rhizostyle (Rhs), mitochondrion-associated lamella (ML), two connections between basal bodies, a striated fibrous root (SR) and a striated fiber-associated microtubular root (SRm). Four types of microtubular roots originated near the ventral basal body and extended toward the left side of the basal bodies. The non-keeled Rhs originated at the Rhs-associated striated fiber, which was located between two basal bodies and extended into the middle of the cell. The ML was a plate-like fibrous structure associated with mitochondria and originating from a Rhs-associated fiber. It split into two parts and extended toward the dorsal-posterior of the cell to a mitochondrion. The SR and SRm extended parallel to the anterior lobe of the cell. The overall configuration of the flagellar apparatus in R. reticulata var. atrorosea was similar to the previously reported descriptions of those of Cryptomonas paramecium, C. pyrenoidifera, C. ovata, Hanusia phi, Guillardia theta, and Proteomonas sulcata. However, the flagellar apparatus system of R. reticulata var. atrorosea was more complex than those of other cryptomonad species due to the presence of an additional microtubular root and other distinctive features, such as a rhizostyle-associated striated fiber and large ML.