• 한국미생물·생명공학회지
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• 제31권3호
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• pp.264-270
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• 2003

1.북부 하수처리장에서 동정된 원생동물 및 후생동물의 종류는 32속으로 섬모충류는 17속이었다. 총 개체수는 연평균 5,266개체/ml(2,631∼9,744)이며, 속별 개체수는 Trachelophyllum이 가장 많았다. 종류별로는 편모충류가 6속(11%), 육질충류 3속(7%), 섬모충류 17속(78%), 후생동물이 6속(4%)이며, 섬모충류는 나구류와 시모류가 각각 33%, 23%을 차지하였다. 총 개체수는 하절기에 감소하고 동절기에 상승하는 경향을 나타내었다. 2. 수온 $20^{\circ}C$ 미만인 경우, 속별 개체수와 유출수 BOD, SS농도는 음의 상관관계가 형성되고, 속별 개체수와 유출수 COD, TN, TP농도는 양의 상관관계가 형성되었다. 상관분석의 결과 $20^{\circ}C$미만의 자료에서 Lepadella가 TP제거율에 대한 지표 미생물로의 가능성이 나타나며, Trochilia, Entosiphon, Coiepus는 TN제거율의 지표미생물로의 가능성이 추정된다. 3. 수온 $20^{\circ}C$ 이상인 경우, $20^{\circ}C$ 미만인 경우보다 상관계수가 낮았으며, 전반적으로 속별 개체수와 수질 항목이 음의 상관관계를 형성하였다. Entosiphon, Paramecium은 출현빈도는 낮지만 유출수 TP농도와 양의 상관관계를, TP제거율과 음의 상관관계를 형성함으로 이들 원생동물속의 개체수 증가시에는 유출수 TP가 악화된다는 점에 주의하면서 운전하여야 한다.

• ALGAE
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• 제32권4호
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• pp.309-324
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• 2017

Recently, the heterotrophic nanoflagellate Katablepharis japonica has been reported to feed on diverse red-tide species and contribute to the decline of red tides. However, if there are effective predators feeding on K. japonica, its effect on red tide dynamics may be reduced. To investigate potential effective protist predators of K. japonica, feeding by the engulfment-feeding heterotrophic dinoflagellates (HTDs) Oxyrrhis marina, Gyrodinium dominans, Gyrodinium moestrupii, Polykrikos kofoidii, and Noctiluca scintillans, the peduncle-feeding HTDs Luciella masanensis and Pfiesteria piscicida, the pallium-feeding HTD Oblea rotunda, and the naked ciliates Strombidium sp. (approximately $20{\mu}m$ in cell length), Pelagostrobilidium sp., and Miamiensis sp. on K. japonica was explored. We found that none of these heterotrophic protists fed on actively swimming cells of K. japonica. However, O. marina, G. dominans, L. masanensis, and P. piscicida were able to feed on heat-killed K. japonica. Thus, actively swimming behavior of K. japonica may affect feeding by these heterotrophic protists on K. japonica. To the contrary, K. japonica was able to feed on O. marina, P. kofoidii, O. rotunda, Miamiensis sp., Pelagostrobilidium sp., and Strombidium sp. However, the specific growth rates of O. marina did not differ significantly among nine different K. japonica concentrations. Thus, K. japonica may not affect growth of O. marina. Our findings suggest that the effect of predation by heterotrophic protists on K. japonica might be negligible, and thus, the effect of grazing by K. japonica on populations of red-tide species may not be reduced by mortality due to predation by protists.

• 생태와환경
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• 제38권4호통권114호
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• pp.494-502
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• 2005

녹조대발생의 원인종인 남조 Microcystis aeruginosa와 규조 Stephanodiscus hantzschii 에 대한 살조 및 섭식능을 갖는 박테리아 및 섬모충을 각각 단독 및 혼합처리하고 살조능을 비교하였다. 먼저 남조 M. aeruginosa에 대하여 살조세균 Streptomyces neyagawensis와 섬모충 Stentor roeselii를단독 및 혼합처리한 결과, 각각의 단독처리가 혼합처리보다 더 높은 살조능을 나타내는 두 생물제재의 길항적 살조효과를 나타냈다. 또한 규조 S. hantzschii 에 대해 살조능을 갖는 박테리아 P seudomonas putida와 S. roeselii를 전과 동일한 방법으로 단독 및 혼합처리하여 결과를 비교하였다. 전 실험과는 다르게 두 생물제재의 혼합처리가 단독처리보다 더 높은 살조능을 보이는 두 생물제재의 상승적 살조효과를 나타냈다. 이러한 결과들은 녹조 제어를 위한 생물제재의 적용시 유용하게 이용될 것이며, 다양한 생물제재를 이용함으로서 수중생태계의 혼란을 초l소화시킬 수 있을 것으로 사료되었다.

• 환경생물
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• 제34권4호
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• pp.281-291
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• 2016

Bloom of small centric diatom Stephanodiscus is quite occasional in winter season in temperate freshwater ecosystems. It often leads to degradation of water quality and affects the quality of supplied drinking water. In a previous study, we have found that naphthoquinone (NQ) 4-6 derivate is an effective tool for efficient mitigation of natural S. hantzschii blooms. In the present research, polylactide (PLA) and agar foam were used as immobilized agent for NQ 4-6 to improve the efficiency of NQ 4-6 compound releasing process for its application under various field conditions. Mesocosm experiments at 10 ton scale suggested that the abundance of S. hantzschii was continuously increased in the control and upon treatment of the mesocosm with immobilized NQ 4-6 from PLA and agar foam. Their algicidal activities were 78.8% and 77.1%, respectively, on S. hantzschii after 10 days. In the mesocosm experiments, the dynamics of biotic (bacteria, HNFs, ciliates, zooplankton) and abiotic (water temperature, dissolved oxygen, pH, conductivity, nutrients) factors remained unaffected. They exhibited similar trends in the control and treatment groups. Therefore, the immobilized NQ 4-6 from PLA and agar foam has potential to be used as an alternative algicidal substance to effectively mitigate natural S. hantzschii blooms under various field conditions. In addition, it not only can be used to control S. hantzschii, but also is an effective technique. The immobilized NQ 4-6 showed stable controlled release in desired system.

• Journal of Photoscience
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• 제7권1호
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• pp.1-4
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• 2000

The photosensory ciliates Blepharisma japonicum and Stentor coeruleus use the hypericin-derived pigments blepharismin and stentorin, respectively, as photoreceptor chromophores. Fluorescence quenching studies have shown that the first excited singlet state of hypericin and the purified chromophores blepharismin and stentorin can be deactivated by electron transfer to an acceptor molecule with a suitable reducing potential [1,2]. This paper reports the result of a series of photobehavioral experiments performed with the aim to ascertain if the same electron accepters which quench the photoreceptor pigment fluorescence in vitro may also compete with the native acceptor molecule in its natural physiological environment. Individual cell trajectories were examined before and after light stimulation, in the presence and in the absence of potential "in vivo" electron accepters, with a microvideo-recording apparatus. Our data, on Blepharisma cells, showed that as the negative reduction potential of the electron acceptor increases, a pronounced decrease in cell photoresponsiveness was detected. A dramatic effect on cell photoresponsiveness was noticed in the presence of 1,4-benzoquinone that has the lowest negative reduction potential. Such an effect on the percentage of photoreacting cells was moderate in the case of 1,4-naphthoquinone, with a relatively higher negative reduction potential. In the presence of benzophenone, which has the highest negative reduction potential, no significant effect on photoreacting cells was noticed. Our results can support the hypothesis that in the pigment granules such a light-induced charge transfer from excited blepharismin to a suitable electron acceptor triggers sensory transduction processes in B. japonicum.

• 한국어병학회지
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• 제19권2호
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• pp.99-108
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• 2006

Diseased tiger puffer (Takijugu rubripes) showed anorexia and severe anemia in the gills. In wet mount preparations Heterobothrium sp. with 4 sets of clamps on the opisthohaptor attached to the gill filaments of the diseased fish. From the drum-shaped filter for filtration of the culturing water and the sediment of aquarium held the diseased fish in the laboratory, their eggs forming long strings through connection of the bipolar filaments could be easily collected. The parasites with 4 pairs of clamps on the opisthohaptor were 2.38mm in length and 0.71 mm in width, but had no isthmus which was separated the opisthohapor from the body proper. The parasites could be easily distinguished from Heterobothrium tetrodonis and H. okamotoi in the absence of distinct isthmus, and resembled H. yamagutii described from the gills of Takifugu xanthopterus in Japan. Their eggs were yellowish spindle in shape and 180-200 x 5-6 Iffil in size, which were pointed at both ends. The eggs were linked to adjacent egg shells like a string of beads by the filaments. Onchomiracidia, ciliated larvae spawned from the eggs were 133 Iffil (120-146 Iffil) x 751ffil (68-80 Iffil) in size. The length of the ciliates was 12 Iffil in the anterior part of the larvae and 14 Iffil in the posterior part. Round or leaf-shaped young parasites attached on the secondary gill lamellae. There was a tendency that most of round smaller parasites without an opisthohaptor were found in the middle part of the gill lamellae while leaf-shaped larger ones with a opisthohaptor attached on the distal part of the gill filaments. Each clamp of mature parasites grasped one secondary gill filament which resulted in bending of the filaments and hyperplasia of the epithelium and mucous cells. In the branchial cavity around the pseudobranch, mature parasites grasped the adjacent ones by means of the clamps, and the epithelia of the branchial cavity around the parasites showed severe irregular hyperplasia and erosion with strongly PAS-positive mucous cells.

• Animal Systematics, Evolution and Diversity
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• 제34권1호
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• pp.37-49
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• 2018

Two hypotrich ciliates, Australocirrus shii (Shi et al., 1997) Kumar & Foissner, 2015 and Afrokeronopsis aurea (Foissner & Stoeck, 2008) Foissner et al., 2010 isolated from freshwater habitats in Korea and were studied based on the specimens from live and after protargol impregnation. Australocirrus shii is redescribed based on morphology and 18S rRNA gene sequence, whereas Af. aurea is the first record for Korea. Main morphological features of the Korean population of Au. shii are as following: body size $100-200{\times}40-80{\mu}m$ in vivo; elongate to ellipsoidal or slightly elongate obovate, dorsoventrally flattened; transverse cirri arranged in (3+2) pattern, anterior pretransverse ventral cirrus distantly anterior of the first transverse cirrus; eight or nine dorsal kineties; and three caudal cirri. Main morphological features of the Korean population of Af. aurea are as following: body size $230-375{\times}70-145{\mu}m$ in vivo; shape elongate obovate or ellipsoidal, widest at the mid-body; undulating membranes in Australocirrus pattern with a buccal depression; and three caudal cirri. The Korean population of A. shii is similar in morphology with previous descriptions except for the presence of indentation at the posterior end in the Korean population. The Korean population of A. aurea is slightly shorter than the South African population and has slightly less marginal and mid-ventral cirri. The phylogenetic analysis of present two Korean hypotrichs and relevant species based on 18S rRNA gene sequences generated almost similar tree topologies compared with previous studies.

• 생태와환경
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• 제37권2호통권107호
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• pp.149-179
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• 2004

국내산 담수 섬모충 플랑크톤의 분류 및 생태학적 특성을 파악하기 위해 2000년 12월 15일부터 2001년 12월6일까지 팔당호에서 표층수를 채집하였다. 조사결과 총 6목 7과 10속 12종의 우점종이 분류, 동정 되었으며 이들은 모두 국내 미기록 종으로서 생태학적 특성과 함께 기재하였다. 우점적으로 동정된 섬모충 플랑크톤의 대부분은 부영양수역에서 보고된 종들이었으며, 저수온기인 동계와 춘계에는 nanoplankton을 먹이로 하는 비교적 대형종인 Codonella cratera, Rimostrombidium lacustris, Strobilidium caudatum, Limnostrombidium viride, Pelagostrombidium fallax, Stylonychia sp., Pseudostrombidium planktonticum, Phascolodon vorticella등이 출현하는 반면, 고수온기인 하계와 추계에는 박테리아를 먹이로 하는 Rimostrombidium hyalinum, Rimostrombidium brachykinetum, Halteria gradinella, Vorticella convallaria와 같은 소형종들이 우점하였다.

• Ocean and Polar Research
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• 제29권4호
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• pp.327-337
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• 2007

Plankton communities have close relationships with environmental changes in water columns. Thus, the use of plankton as a biological tool for assessing the marine ecosystem health may be effective. Major issue regarding coastal pollution has been usually recognized as phytoplankton blooms or red tides caused by the eutrophication, an increase in concentration of inorganic nutrients such as nitrogen and phosphorus. However, in order to understand the effects of the overall pollution on marine ecosystem, the organic pollutants as well as the inorganic nutrients should be also considered. For understanding the effects of the organic pollution, among the planktonic organisms, heterotrophic bacteria, heterotrophic flagellates and ciliates should be investigated. Generally, there are three approaches for assessing the marine ecosystem health using the plankton taxa or plankton communities. The first one is a community-based approach such as diversity index and chlorophyll a concentration which are common in analysis of the plankton communities. The second is an indiviual-based approach which is to monitor the pollution indicative species. This approach needs one's ability to identify the plankton to species level. The last approach is a bioassay of toxicity, which can be applied to the plankton. A pilot study in Masan Bay was conducted to assess the effects of the inorganic and organic pollution. In this article, a new approach using plankton communities was tentatively presented as a biological tool for assessing the ecosystem health of Masan Bay.

• ALGAE
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• 제34권2호
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• pp.127-140
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• 2019

The species in the dinoflagellate order Suessiales have 5-24 latitudinal paraplate series and include many fossil and extant species. There have been a few studies on the ecophysiology of the phototrophic species Biecheleriopsis adriatica, and no study on its predators. Thus, we explored the feeding occurrence by common heterotrophic protists on B. adriatica and the growth and ingestion rates of the heterotrophic dinoflagellate Oxyrrhis marina on B. adriatica BATY06 as a function of prey concentration. The common heterotrophic dinoflagellates Aduncodinium glandula, O. marina, Gyrodinium dominans, Gyrodinium moestrupii, Luciella masanensis, Pfiesteria piscicida, and Oblea rotunda and two naked ciliates Strombidinopsis sp. and Pelagostrobilidium sp. were able to feed on B. adriatica, but the heterotrophic dinoflagellate Polykrikos kofoidii was not. However, B. adriatica supported the positive growth of O. marina, but did not support that of G. dominans and O. rotunda. With increasing prey concentrations, the growth and ingestion rates of O. marina on B. adriatica increased and became saturated. The maximum growth rate of O. marina on B. adriatica was $0.162d^{-1}$. Furthermore, the maximum ingestion rate of O. marina on B. adriatica was $0.2ng\;C\;predator^{-1}\;d^{-1}$ ($2.0cells\;predator^{-1}\;d^{-1}$). In the order Suessiales, the feeding occurrence by common heterotrophic protists on B. adriatica is similar to that on Effrenium voratum and Biecheleria cincta, but different from that on Yihiella yeosuensis. However, the growth and ingestion rates of O. marina on B. adriatica are considerably lower than those on E. voratum and B. cincta, but higher than those on Y. yeosuensis. Therefore, B. adriatica may be less preferred prey for O. marina than E. voratum and B. cincta, but more preferred prey than Y. yeosuensis.