• 한국해양학회지:바다
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• 제9권4호
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• pp.164-172
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• 2004

담수의 유입량 및 유입특성이 서로 다른 서해의 곰소만과 금강하구역에서 1999년 9월부터 2000년 12월까지 0.5-2주일 간격으로 수온, 염분, 식물플랑크톤 군집 및 Mesodinium rubrum(=Myrionecta rubra) 개체군의 변동 특성을 연구하였다. 두 해역에서 수온과 염분 환경의 차이에 의한 식물플랑크톤 군집과 M. ruburm개체군의 시계열적 변동 양상의 상이성에 대하여 비교 $.$분석하였다. 불규칙한 담수 방류에 의하여 상류 기원의 부영양물질의 유입이 많은 금강하구역에서는 곰소만에 비하여 평균 밀도가 더 높은 M. ruburm개체군이 유지됨과 동시에, M. ruburm대발생의 빈도와 규모가 더 크다는 사실이 확인되었다 또한 보다 급격한 염분 변화를 보였던 금강하구역에서는 Skeletonema costatum을 비롯한 Asterionellopsis glacialis, A. kariana, Chaetoceros debilis, Eucampia zodiacus, Paralia sulcata, Thalassiosira pacifica, T. nordenskioeldii 등의 연안성 규조류의 우점도가 곰소만에서 보다 낮았던 반면, 염분 변화에 대한 내성이 강한 M. ruburm이 높은 우점율을 나타내었다. 향후 서해 연안에 새만금방조제와 같은 인공구조물이 건설되어 불규칙한 담수 방류의 빈도와 규모가 증가할 경우, 인근 해역에는 우점 규조류 대신 M. ruburm이 우점하게 될 가능성이 있다.

• Asian-Australasian Journal of Animal Sciences
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• 제26권4호
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• pp.517-522
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• 2013

The effect on methanogens attached to the surface of rumen ciliate protozoa by the addition of plant extracts (pine needles and ginkgo leaves) was studied with particular reference to their effectiveness for decreasing methane emission. The plant extracts (pine needles and ginkgo leaves) were added to an in vitro fermentation incubated with rumen fluid. The microbial population including bacteria, ciliated-associated methanogen, four different groups of methanogens and Fibrobacter succinogenes were quantified by using the real-time PCR. Gas profiles including methane, carbon dioxide and hydrogen, and runinal fermentation characteristics were observed in vitro. The methane emission from samples with an addition of individual juices from pine needles, ginkgo leaves and 70% ethanol extract from ginko leaves was significantly lower (p<0.05, 27.1, 28.1 and 28.1 vs 34.0 ml/g DM) than that of the control, respectively. Total VFAs in samples with an addition of any of the plant extracts were significantly lower than that of the control (p<0.05) as well. The order Methanococcales and the order Methanosarcinales were not detected by using PCR in any incubated mixtures. The ciliate-associated methanogens population decreased from 25% to 49% in the plant extacts as compared to control. We speculate that the supplementation of juice from pine needles and ginkgo leaves extract (70% ethanol extract) decreased the protozoa population resulting in a reduction of methane emission in the rumen and thus inhibiting methanogenesis. The order Methanobacteriales community was affected by addition of all plant extracts and decreased to less than the control, while the order Methanomicrobiales population showed an increase to more than that of the control. The F. succinogenes, the major fibrolytic microorganism, population in all added plant extracts was increased to greater than that of the control. In conclusion, pine needles and ginkgo leaves extracts appear to have properties that decrease methanogenesis by inhibiting protozoa species and may have a potential for use as additives for ruminants.

• ALGAE
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• 제32권1호
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• pp.47-55
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• 2017

We explored feeding by the mixotrophic ciliate Mesodinium rubrum, heterotrophic nanoflagellates (HNFs), and small ciliates (<$30{\mu}m$ in cell length) on natural populations of heterotrophic bacteria in Masan Bay, Keum River Estuary, and in the coastal waters of the Saemankeum area, Korea when M. rubrum red tides occurred. We also measured ingestion rates of M. rubrum on cultured heterotrophic bacteria as a function of bacterial concentration in the laboratory. The ingestion rates of M. rubrum on natural populations of heterotrophic bacteria (2.3-16.8 bacteria $grazer^{-1}h^{-1}$) were comparable to or lower than those of co-occurring HNFs (10.7-41.7 bacteria $grazer^{-1}h^{-1}$), but much lower than those of co-occurring small ciliates (76.0-462.2 bacteria $grazer^{-1}h^{-1}$). However, the maximum grazing coefficient of M. rubrum ($0.245d^{-1}$) on natural populations of heterotrophic bacteria was much higher than that of small ciliates ($0.089d^{-1}}$), and slightly higher than that of HNFs ($0.204d^{-1}$). With increasing bacterial concentrations, ingestion rates of M. rubrum on cultured heterotrophic bacteria continuously increased, but became saturated at higher prey concentrations over $1-5{\times}10^6cells\;mL^{-1}$. The maximum ingestion rate of M. rubrum on cultured heterotrophic bacteria was 34.4 bacteria $grazer^{-1}h^{-1}$. Based on the present study, it is suggested that M. rubrum may be an important grazer of heterotrophic bacteria and sometimes have considerable grazing impact on natural populations of heterotrophic bacteria.

• 한국유기농업학회지
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• 제26권4호
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• pp.775-787
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• 2018

본 연구는 반추동물의 메탄 감소에 효과가 있는 합성첨가제를 대체 할 수 있는 천연첨가제를 찾고자 연구를 실시하였다. 첨가제인 MRA-1(파), MRA-2 (SLS), MRA-3 (SDS), MRA-4(파+탄닌산)를 만들어 발효시간대별(3, 6, 9, 12, 24 및 48 h) in vitro 시험을 실시하였다. pH는 발효시간동안 적정범위였으며, 건물소화율은 모든 발효시간대별 모든 처리구에서 대조구와 유의적(P>0.05)인 차이를 보이지 않았고, 미생물성장량에도 부정적인 영향을 미치지 않았다. 메탄 발생량은 발효 24시간대 MRA-1구를 제외한 나머지 처리구에서 대조구에 비해 유의적(P<0.05)으로 낮게 측정되었으며, 특히 이산화탄소 발생량은 MRA-4 첨가구에서 발효 9, 24, 48시간대에서 유의적(P<0.05)으로 낮았다. 메탄생성량 감소에 영향이 있는 프로피온산 함량은 발효 24시간대 MRA-4구에서 대조구에 비해 유의적(P<0.05)으로 높았다. Ciliate-associated methanogens은 발효 24시간대 MRA-1, MRA-3 및 MRA-4구에서 대조구에 비해 유의적(P<0.05)으로 낮게 측정되었다. 따라서 파와 탄닌산은 반추위 내 메탄 저감 효과가 있는 합성첨가제를 대체 할 수 있어 반추동물용 천연 메탄 저감제로서의 활용 가능성이 있을 것으로 사료된다.

• ALGAE
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• 제38권1호
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• pp.57-70
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• 2023

The mortality rate of red-tide dinoflagellates owing to predation is a major parameter that affects their population dynamics. The dinoflagellates Ansanella granifera and Ansanella sp. occasionally cause red tides. To understand the interactions between common heterotrophic protists and A. granifera, we explored the feeding occurrence of nine heterotrophic protists on A. granifera and the growth and ingestion rates of the heterotrophic dinoflagellate Gyrodinium dominans on A. granifera as a function of prey concentration and those of Oxyrrhis marina at a single high prey concentration. The heterotrophic dinoflagellates Aduncodinium glandula, G. dominans, Gyrodinium moestrupii, Luciella masanensis, Oblea rotunda, O. marina, Polykrikos kofoidii, and Pfiesteria piscicida and the naked ciliate Strombidium sp. were able to feed on A. granifera. With increasing mean prey concentrations, the growth and ingestion rates of G. dominans feeding on A. granifera rapidly increased and became saturated or slowly increased. The maximum growth and ingestion rates of G. dominans on A. granifera were 0.305 d^-1 and 0.42 ng C predator^-1 d^-1 (3.8 cells predator^-1 d^-1), respectively. Furthermore, the growth and ingestion rates of O. marina on A. granifera at 1,700 ng C mL^-1 (15,454 cells mL^-1) were 0.037 d^-1 and 0.19 ng C predator^-1 d^-1 (1.7 cells predator^-1 d^-1), respectively. The growth and ingestion rates of G. dominans and O. marina feeding on A. granifera were almost the lowest among those on the dinoflagellate prey species. Therefore, G. dominans and O. marina may prefer A. granifera less than other dinoflagellate prey species. The low mortality rate of A. granifera may positively affect its bloom formation.

• 환경생물
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• 제33권4호
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• pp.375-382
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• 2015

We discovered three soil ciliates of the class Colpodea-Colpoda henneguyi Fabre-Domergue, 1889; C. lucida Greeff, 1888; and Bursaria truncatella $M{\ddot{u}}ller$, 1773 from Obong-ri, Ayajin-ri and Elwang-ri (Korea), respectively. Colpoda henneguyi had the following features: often wider preorally than postorally, size in vivo $60-80{\mu}m{\times}50-70{\mu}m$; extrusomes indistinct in vivo, cylindroid approximately $1{\mu}m$ long; notches caused by deep diagonal groove; yellowish globules on the cortex of the cell; 10-12 postoral kineties; silverline system aspera-type. Colpoda lucida exhibited the following features: broadly reniform, size in vivo $70-90{\mu}m{\times}50-70{\mu}m$; conspicuous extrusomes, $3.5-5{\mu}m$ long in vivo, cylindroid to fusiform; 13-16 postoral kineties; silverline system cucullus-type. Bursaria truncatella had the following features: bursiform, size in vivo $300-470{\mu}m{\times}120-260{\mu}m$; macronucleus coiled with highly variable shapes, $600-1100{\mu}m{\times}30-40{\mu}m$ long in vivo; micronuclei 16-25 in number, approximately $4{\mu}m$ in diameter; extrusomes cylindroid, $3-4{\mu}m$ long in vivo. This is the first report of colpodean ciliates from Korea, and we describe these species based on observations of live and impregnated (protargol and silver nitrate impregnation) specimens.

• Asian-Australasian Journal of Animal Sciences
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• 제9권6호
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• pp.667-670
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• 1996

Four Murrah male buffalo calves with an average body weight of $188{\pm}1.6kg$ each fitted with rumen and abomasal cannula were subjected to defaunation followed by refaunation. The animals were offered wheat straw and a concentrate mixture. There was no difference in dry matter, starch and nitrogen intake in defaunated and refaunated buffalo calves. Production of ruminal total volatile fatty acid and acetate : propionate ratio decreased (p < 0.01) whereas, molar proportion of propionate increased (25.8 Vs 19.4% p < 0.01) in defaunated animals. Fermentation of starch in rumen increased (73.9 Vs 65.8%, p < 0.01) but in small intestine decreased (20.2 Vs. 28.2%, p < 0.05) in defaunated calves. The flow of non ammonia nitrogen (NAN) to abomasum (75.1 vs 68.6 g/d, p < 0.01) and its digestion in small intestine (37,6 vs 32.5 g/d, p < 0.01) was improved due to defaunation. However, No difference in the total tract digestibility of starch and nitrogen was found in defaunated and refaunated buffalo calves.

• Animal Systematics, Evolution and Diversity
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• 제34권3호
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• pp.143-151
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• 2018

A marine ciliate Amphisiella milnei (Kahl, 1932) $Horv{\acute{a}}th$, 1950 was discovered from the tidal pool of Baekdo Island, South Korea. The existence of extra cirri between leftmost frontal cirrus and buccal cirrus discriminates this species from its congeners. Its morphological features are described as follows: body size in vivo $110-130{\times}35-45{\mu}m$; elongate rectangular to elliptical in shape; two large and several small ring-shaped structures; yellowish cortical granules arranged irregularly on ventral side but longitudinally along dorsal kineties on dorsal side; 34-40 adoral membranelles, 3 frontal cirri, 1 buccal cirrus, 1 parabuccal cirrus, usually 2 extra cirri behind leftmost frontal cirrus, and 3 frontoventral cirri; amphisiellid median cirral row composed of 25-31 cirri with 27-36 left and 27-44 right marginal cirri; usually 5 transverse cirri and 2 pretransverse cirri with 7 dorsal kineties; two macronuclear nodules. In addition to, 18S rDNA sequence of A. milnei was analyzed to understand its phylogenetic relationship.

• ALGAE
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• 제34권4호
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• pp.289-301
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• 2019

Mixotrophy in marine organisms is an important aspect of ecology and evolution. The discovery of mixotrophic abilities in phototrophic dinoflagellates alters our understanding of the dynamics of red tides. In the phototrophic dinoflagellate genus Alexandrium, some species are mixotrophic, but others are exclusively autotrophic. There are differences in the ecological roles of autotrophic and mixotrophic Alexandrium in marine food webs. However, of the 34 known Alexandrium species, the mixotrophic ability of >20 species has yet to be explored. In this study, the mixotrophic capabilities of Alexandrium insuetum CCMP2082, Alexandrium mediterraneum CCMP3433, Alexandrium pacificum CCMP3434, Alexandrium tamutum ATSH1609, and Alexandrium margalefii CAWD10 were investigated by providing each species with 22 diverse prey items including bacterium-sized microbeads (1 ㎛), the cyanobacterium Synechococcus sp., algal prey species, and the ciliate Mesodinium rubrum. None of the 5 Alexandrium species fed on any of the prey items. These results increase the number of Alexandrium species lacking mixotrophic abilities to 9, compared to the 7 known mixotrophic Alexandrium species. Furthermore, the Alexandrium phylogenetic tree based on the large subunit ribosomal DNA contained 3 large clades, each of which had species with and without mixotrophic abilities. Thus, the acquisition or loss of mixotrophic abilities in Alexandrium might readily occur.

• Animal Systematics, Evolution and Diversity
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• 제19권2호
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• pp.237-244
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• 2003

울산 인근의 연못 가장자리 수초에서 채집된 섬모충류가 겹가지섬모충과 (Epistylidae)에 속하는 겹가지섬모충(Epistylis plicatilis Ehrenberg, 1831)과 빈겹가지섬모충 (E. hentscheli Kahl, 1935)으로 각각 동정되어 재기재하였다. 이 종들은 한국에서 처음 보고되는 종들로서 생체표본과 protargol로 염색한 표본에 근거하여 재기재하였다. 원기재와 유사종들과 비교하였는데 겹가지섬모충 (E. plicatilis)은 가늘고 긴 깔대기 형태를 가지며 줄기는 근섬유로 속이 찬 형태이다. 반면에 빈겹가지섬모충 (E. hentscheli)는 비대칭의 종 모양을 띠며 줄기는 속이 텅 빈 형태이다.