• 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.26 no.1
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• pp.87-96
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• 2011

Protein profiles of a common mixotrophic dinoflagellate, Prorocentrum micans, growing autotrophically and mixotrophically (fed on the cryptophyte Rhodomonas salina) were compared using two-dimensional gel electrophoresis (2-DE) to determine if they vary in different trophic modes. Approximately 2.3% of the detected proteins were differentially expressed in the different trophic modes. Twelve proteins observed only in the mixotrophic condition had lower pI value (<5) than the fifteen proteins observed only in the autotrophic condition (>5). When the internal amino acid sequences of five selected proteins differentially expressed between autotrophic and mixotrophic conditions were analyzed using matrix-assisted laser desorption time-of-flight (MALDI-TOF) mass spectrometry, two proteins that were specifically expressed in the autotrophic condition showed homology to glyceraldehyde-3-phosphatase dehydrogenase (GAPDH) and a bacterial catalase. Three mixotrophy-specific proteins showed homology to certain hypothetical proteins from an insect and bacteria. These results suggested the presence of certain gene groups that are switched on and off according to the trophic mode of P. micans.

• Korean Journal of Environmental Biology
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• v.30 no.1
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• pp.1-8
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• 2012

To understand growth characteristics of eight dominant red tide species ($Prorocentrum$ $minimum$, $Heterocapsa$ $triquetra$, $Scrippsiella$ $trochoidea$, $Akashiwo$ $sanguinea$, $Chattonella$ $marina$, $Heterosigma$ $akashiwo$, $Amphidinium$ $carterae$ and $Rhodomonas$ $salina$) in the Korean coastal water, the growth rates were examined in relation with the impacts of water temperature and bio-volume. Of these, $P.$ $minimum$, $C.$ $marina$, $H.$ $akashiwo$, $A.$ $carterae$ and $R.$ $salina$ were eurythermal species with relatively high growth rates in a borad ranges (15 to $25^{\circ}C$) of water temperature. On the other hand, the growth rate of $H.$ $triquetra$, $S.$ $trochoidea$ and $A.$ $sanguinea$ were high in relatively mid temperature (optimum: $25^{\circ}C$) condition. In particular, $H.$ $triquetra$ was well adapted in low temperature of 5 to $15^{\circ}C$, implying that the species can survive and grows even at very low temperature. Based on results of our experiment, the growth characterestics of five eurythermal species and three mid temperature species may have dominated in Korean coastal water during summer season and fall season, respectively. Contrastively, the growth characteristics of $H.$ $triquetra$ make a consistently dominant during the cold winter season. In addition, the growth rates of large bio-volume species were lower than those of small bio-volume species, indicates that growth of single cells of several flagellates might be depended on the cells sizes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2951-2957
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• 2015

The development of worldwide harmful algal blooms(HAB) is a serious problem for public health and fisheries industries. To evaluate the algicidal impact on the HAB species, algicide thiazolidinedione derivative (TD49) and yellow clay were examined, which is focus on assess the algicidal effects and inhibition to photosynthesis of HAB species. To obtain the detailed information, we analyzed the viability of target species related to activity Chl. a, photosynthetic efficiency($F_v/F_m$), and electron transport rate(ETR). Culture experiment was conducted to evaluate the algicidal effects of three harmful species(raphidophyceae Heterosigma akashiwo, Chattonella marina, and dinophyceae Heterocapsa circularisquama) and one non-harmful species (cryptophyceae Rhodomonas salina). Our experiments revealed that three HAB species were easily destroyed of the cell walls after TD49 dosing. Also, they had significantly reducing values of active Chl. a, $F_v/F_m$, and ETR, due to the damage of photosystem II by inter-cellular disturbance. As a result, the algicidal effect(%) for the three HABs were as follows, in the order of greatest to the least: H. circularisquama> C. marina> H. akashiwo. However, the algicidal effect for yellow clay remained to be <30% (p>0.01), implying that it may not have damaged the photosystem II. On the other hand, non-HAB R. salina was promoted at both TD49 and yellow clay treatments. Our results demonstrated that the TD49 is a good agent for the control of HABs H. akashiwo, C. marina, and H. circularisquama, whereas the yellow clay would not be suitable for the field application based on our experimental results.

• ALGAE
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• v.31 no.1
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• pp.17-31
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• 2016

To explore the feeding ecology of the newly described heterotrophic dinoflagellate Aduncodinium glandula in the family Pfiesteriaceae, its feeding behavior and prey species were investigated. Additionally, the growth and ingestion rates of A. glandula on the mixotrophic dinoflagellates Heterocapsa triquetra and Akashiwo sanguinea, its optimal and suboptimal prey, respectively were measured. A. glandula fed on prey through a peduncle after anchoring to the prey using a tow filament. A. glandula ate all algal prey and perch blood cells tested and had the most diverse prey species in the family Pfiesteriaceae. Unlike for other pfiesteriacean species, H. triquetra and A. sanguinea support the positive growth of A. glandula. However, the cryptophytes Rhodomonas salina and Teleaulax sp. and the phototrophic dinoflagellate Amphidinium carterae did not support the positive growth of A. glandula. Thus, A. glandula may have a unique kind of prey and its optimal prey differs from that of the other pfiesteriacean dinoflagellates. With increasing mean prey concentration, the growth rates of A. glandula on H. triquetra and A. sanguinea increased rapidly and then slowed or became saturated. The maximum growth rates when feeding on H. triquetra and A. sanguinea were 1.004 and 0.567 d⁻¹, respectively. Further, the maximum ingestion rates of A. glandula on H. triquetra and A. sanguinea were 0.75 and 1.38 ng C predator⁻¹ d⁻¹, respectively. There is no other pfiesteriacean species having H. triquetra and A. sanguinea as optimal and suboptimal prey. Thus, A. glandula may be abundant during blooms dominated by these species not preferred by the other pfiesteriacean dinoflagellates.