Growth and ingestion rates of heterotrophic dinoflagellates and a ciliate on the mixotrophic dinoflagellate Biecheleria cincta

유영두,윤은영,이경하,강남선,정해진 한국조류학회I 2013 ALGAE Vol.28 No.4

To explore the interactions between the mixotrophic dinoflagellate Biecheleria cincta (previously Woloszynskia cincta) and heterotrophic protists, we investigated whether the common heterotrophic dinoflagellates Gyrodinium dominans, Gyrodinium moestrupii, Gyrodinium spirale, Oxyrrhis marina, and Polykrikos kofoidii, and the ciliate Strobilidium sp. were able to feed on B. cincta. We also measured growth and ingestion rates of O. marina and Strobilidium sp. on B. cincta as a function of prey concentration. In addition, these rates were measured for other predators at single prey concentrations at which the growth and ingestion rates of O. marina and Strobilidium sp. were saturated. All grazers tested in the present study were able to feed on B. cincta. B. cincta clearly supported positive growth of O. marina, G. dominans, and Strobilidium sp., but it did not support that of G. moestrupii, G. spirale, and P. kofoidii. The maximum growth rates of Strobilidium sp. and O. marina on B. cincta (0.91 and 0.49 d-1, respectively) were much higher than that of G. dominans (0.07 d-1). With increasing the mean prey concentration, the specific growth rates of O. marina and Strobilidium sp. on B. cincta increased, but either became saturated or slowly increased. The maximum ingestion rate of Strobilidium sp. (1.60 ng C predator-1 d-1) was much higher than that of P. kofoidii and O. marina (0.55 and 0.34 ng C predator-1 d-1) on B. cincta. The results of the present study suggest that O. marina and Strobilidium sp. are effective protistan grazers of B. cincta.

우리나라에 서식하는 유독성 와편모조류 Alexandrium pseudogonyaulax의 형태학적 및 분자생물학적 특성 연구

유영두,황영종,이무준 한국수로학회 2023 한국수로학회지 Vol.12 No.2

본 연구에서는 서해안에 위치한 시화호와 비응항에서 Alexandrium을 채집하고 단일 종 배양에 성공하였으며 형태학적 및 분자생물학적 분석을 수행하였다. Kofoidian series에 의한 thecal plate formula는 전형적인 Alexandrium 속의 thecal plate formula를 따랐다. 본 연구에서 단종배양체를 확립한 종은 대부분의 세포가 길이와 너비의 비율이 비슷하거나 너비가 길이에 비해 긴 넓적한 형태로 관찰되었으며 S.s.a의 형태가 비교적 넓고 큰 특징을 보였다. 또한 SSU 및 LSU rDNA 염기서열에 기반한 분자계통도 분석 결과 Alexandrium pseudogonyaulax와 가장 가까운 근연관계를 보였다. 따라서 본 연구에서 채집되어 단일 종 배양에 성공한 Alexandrium은 형태학적으로 봤을 때 세포의 형태(shape), 길이와 너비의 비율 및 plate formula 구성의 특징이 A. hiranoi 보다 A. pseudogonyaulax에 더 유사한 것으로 판단되며 rDNA (SSU, LSU) 염기서열 및 분자계통도 분석 결과 또한 A. pseudogonyaulax와 가장 유사한 것으로 판단된다. The strain within the genus Alexandrium was isolated from western coast of Korea, and subsequent morphological and molecular analyses were conducted. Thecal plate formula by Kofoidian series followed that of the typical genus Alexandrium. Most of the cells were observed to be broadly shaped with a similar ratio of length to width or the width longer than length, and the morphology of S.s.a. was characterized as relatively broad and large. In addition, molecular phylogenetic analysis based on SSU and LSU rDNA sequences showed that Alexandrium pseudogonyaulax was the closest related species. Consequently, through morphological assessments of cell shape, length-width ratio, and plate formula composition, coupled with the analysis of rDNA (SSU, LSU) sequence differences and phylogenetic positions, the isolate examined in this study is found to be similar to A. pseudogonyaulax.

전북 새만금 남쪽 해역의 유해성 적조 발생연구 1. 1999년도 여름-가을 식물플랑크톤의 시공간적 변화

유영두,정해진,심재형,박재연,이경재,이원호,권효근,배세진,박종규 한국해양학회 2002 바다 Vol.7 No.3

대규모 간척사업이 진행되고 있는 전북 새만금 해역에서 Cochlodinium polykrikoides가 우점하는 유해성 적조의 발생에 대한 연구를 하기 위하여, 1999년 8월 10일부터 11월 11일까지 모두 5차례에 걸쳐 4개 정점에서 시료를 채집한 뒤 적조원인생물의 시공간적 분포와 수온, 염분, 영양염류 분포 등 환경요인들과의 연관성을 연구하였다. 조사기간 중 출현한 유해성 적조생물은 Alexandrium tamarense, C. polykrikoides, Gymnodnium catenatum, Gyrodinium aureolum, Gymnodnium impudicum 등 이며, 크기 20$mu extrm{m}$ Gymnodinium sp.는 8월 10일 264 cells $m\ell$$^{-1}$, G. aureolum은 9월 16일 200 cells $m\ell$$^{-1}$, G. polykrikoides는 10월 18일 463cells $m\ell$$^{-1}$의 최대풍도로 적조를 일으켜 조사 시기에 따라 다양한 종들이 적조를 일으킨다는 것을 알 수 있었다. 1997년 전남 고흥 나로도 해역에서 발생된 C. poiykrikoides 적조발생과 비교하면 새만금 해역에서는 적조가 시기적으로 약 50일 정도 늦게 발생하였고, 6$^{\circ}C$ 정도 낮은 수온에서 발생하였다. C. polykrikoides는 9월 16일에 처음으로 발견되었는데(최대풍도: 5 cells $m\ell$$^{-1}$), 20~$25^{\circ}C$수온에서의 최대성장율(0.3~0.4 d$^{-1}$)을 감안하였을 때 이미 외부에서 만들어진 적조 띠가 연구해역으로 유입되지 않고 자체성장만으로도 10월 18일의 최대풍도에 도달할 수 있다고 판단된다. 새만금 해역과 고흥 해역 모두 C. polykrikoides 적조는 주로 규조류의 풍도가 낮은 환경에서 나타나, 규조류와의 경쟁에서 유리한 환경조건이 갖춰졌을 때 C. polykrikoides가 우점하게 된다고 추정할 수 있다 We investigated the outbreak of red tides dominated by harmful dinoflagellates from August to November 1999 in the coastal waters off the southern Saemankeum areas where a huge red tide dominated by Cochlodinium polykrikoides had been first observed in 1998. We took water samples from 2~5 depths of 4 stations (with 3-4 additional stations during red tides) in this study period and then measured the abundance of phytoplankton, water temperature, salinity, and the concentrations of nutrients. In the study period harmful dinoflagellates Alexandrium tamarense, C. polykrikoides, Gymnodnium catenatum, Gyrodinium aureolum, Gymnodnium impudicum were present, and of these G. aureolum and C. polykrikoides formed red tide patches on September 16 and October 18, respectively. The date of the outbreak of red tide dominated by C. polykrikoides in the study area was approximately 50 days later than that off the Kohung areas in 1997 and the surface water temperature when the red tides outbroke in the former area was 6$^{\circ}C$ lower than that fur the latter area. The maximum abundance of C. polykrikoides on September 16, October 7 and 18 were 5, 14, and 463 cells $m\ell$$^{-1}$ , respectively. The growth rate of C. polykrikoides, isolated from the study area, was 0.3~0.4 d$^{-1}$ at 20~$25^{\circ}C$, which enable this species to reach the maximum concentration without being transported from the adjacent waters containing already made red tide patches. The outbreaks of red tides dominated by C. polykrikoides in the study area and off Kohung have occurred when and/or where the concentrations of diatoms were low. This evidence suggests that the outbreak of red tides dominated by C. polykrikoides is adversely affected by the high diatom concentrations or the conditions favorable for the growth of diatoms.

영어 의문사 연구

유영두 한국영어학학회 1997 영어학연구 Vol.- No.4

도로우 : 불교적 성자 a Buddhist Saint

柳永斗 상명대학교 어문학연구소 1994 語文學硏究 Vol.2 No.-

Henry David Thoreau was bred to no profession; he never married; he lived alone; he never went to church in New England Christian society; he ate no flesh, he drank no wine, he never knew the use of tabacco. He lived like a typical Buddhist monk. He attacked Christianity. He preferred Indian scriptures rather than the Bible, and Buddha rather than Christ. He lived poor but he never wanted to be rich. He worked only to keep his body healthy. He spent his free time on reading, writing and meditation. He was a man of plain living and high thinking. He was friends with animals. He conversed with woodchucks. Snakes coiled round his leg; fishes swam into his hand, and he took them out of the water. In his meditation, he sat immovable, a part of the rock he rested on. Like the oldest Egyption or Hindoo philosopher, he raised a corner of the veil from the statue of the divinity. He flew to God when the channel of purity was open. I think that Thoreau lived a saint's life we can find in Sung-Chul Lee, a Buddhist monk in Korea.

헤밍웨이의 유산자와 무산자

柳永斗 상명대학교 논문집 1988 상명대학교논문집 Vol.21 No.-

In this paper Ernest Hemingway is discussed to be a proletarian writer. His work, To Have and Have Not is the key novel in his Marxist writings. The hero, Harry Morgan was a poor fisherman. He wanted to live an honest life but capitalistic system forced him to commit crimes and eventually be killed. As he was dying, he said "One man alone ain't got bloody fucking chance.' "This became a kind of slogan to those members of the American Left. With Harry's last words, Hemingway signaled his own rejection of the separate peace and acceptance of a united front, a kind of communist tactics. Hemingway must have thought that "Have Not" could be "Have" through communist revolutions.

Ingestion of the unicellular cyanobacterium Synechococcus by the mixotrophic red tide ciliate Mesodinium rubrum

유영두,성경아,명금옥,김형섭,정해진,Brian Palenik,이원호 한국조류학회I 2015 ALGAE Vol.30 No.4

We explored phagotrophy of the phototrophic ciliate Mesodinium rubrum on the cyanobacterium Synechococcus. The ingestion and clearance rates of M. rubrum on Synechococcus as a function of prey concentration were measured. In addition, we calculated grazing coefficients by combining the field data on abundance of M. rubrum and co-occurring Synechococcus spp. with laboratory data on ingestion rates. The ingestion rate of M. rubrum on Synechococcus sp. linearly increased with increasing prey concentrations up to approximately 1.9 × 106 cells mL-1, to exhibit sigmoidal saturation at higher concentrations. The maximum ingestion and clearance rates of M. rubrum on Synechococcus were 2.1 cells predator-1 h-1 and 4.2 nL predator-1 h-1, respectively. The calculated grazing coefficients attributable to M. rubrum on cooccurring Synechococcus spp. reached 0.04 day-1. M. rubrum could thus sometimes be an effective protistan grazer of Synechococcus in marine planktonic food webs. M. rubrum might also be able to form recurrent and massive blooms in diverse marine environments supported by the unique and complex mixotrophic arrays including phagotrphy on hetrotrophic bacteria and Synechococcus as well as digestion, kleptoplastidy and karyoklepty after the ingestion of cryptophyte prey.

Four New Furanosesquiterpenes Isolated from the Marine Sponge Dysidea species

유영두,노정래 한국자기공명학회 2023 Journal of the Korean Magnetic Resonance Society Vol.27 No.4

From a marine sponge Dysidea species, four new furanosesquiterterpenoids were isolated and characterized. Their structural elucidation was achieved through an extensive analysis employing NMR, MS data, and DFT method. Notably, all compounds shared as identical molecular formula. Compound 2 was identified as a derivative of compound 1, while compounds 3 and 4 exhibited an identical planar structure. Determination of the configurations of chiral centers in compounds 1 and 2 involved a comparative analysis between measured and calculated ECD spectra, along with the application of DP4+ probability analysis. Distinctly, the configurations of isomers 3 and 4 were established by scrutinizing proton chemical shifts based on the NOE correlation.

Growth, Feeding and Ecological Roles of the Mixotrophic and Heterotrophic Dinoflagellates in Marine Planktonic Food Webs

정해진,유영두,김재성,성경아,강남선,김태훈 한국해양과학기술원 2010 Ocean science journal Vol.45 No.2

Planktonic mixotrophic and heterotrophic dinoflagellates are ubiquitous protists and often abundant in marine environments. Recently many phototrophic dinoflagellate species have been revealed to be mixotrophic organisms and also it is suggested that most dinoflagellates may be mixotrophic or heterotrophic protists. The mixotrophic and heterotrophic dinoflagellates are able to feed on diverse prey items including bacteria,picoeukaryotes, nanoflagellates, diatoms, other dinoflagellates, heterotrophic protists, and metazoans due to their diverse feeding mechanisms. In turn they are ingested by many kinds of predators. Thus, the roles of the dinoflagellates in marine planktonic food webs are very diverse. The present paper reviewed the kind of prey which mixotrophic and heterotrophic dinoflagellates are able to feed on, feeding mechanisms, growth and ingestion rates of dinoflagellates, grazing impact by dinoflagellate predators on natural prey populations, predators on dinoflagellates, and red tides dominated by dinoflagellates. Based on this information, we suggested a new marine planktonic food web focusing on mixotrophic and heterotrophic dinoflagellates and provided an insight on the roles of dinoflagellates in the food web.

전북 새만금 남쪽 해역의 유해성 적조 발생연구 2. 1999년도 여름-가을 종속영양성 와편모류와 섬모충류의 시간적 변화

정해진,유영두,김재성 한국해양학회 2002 바다 Vol.7 No.3

전북 새만금 해역에서 1998년에 처음으로 유해성 적조생물인 Cochlodinium polykrikoides/Gymnodinium impudicum이 우점하는 대규모 적조가 발생한 뒤 유해성 적조의 반복적인 발생에 대한 우려가 증폭되고 있으므로, 이 해역의 적조생물을 비롯한 식물플랑크톤 동향과 이에 영향을 줄 수 있는 상위포식자인 원생동물에 대한 연구가 절실히 필요한 시점이다. 이 해역에서의 원생동물의 시간적 변화에 대한 연구를 하기 위하여, 1999년 8월 10일부터 11월 11일까지 모두 5차례에 걸쳐 매번 4개 정점의 2-5개 수층에서 시료를 채집하였다. 원생동물인 종속영양성 와편모류와 섬모충류(ciliates)의 종조성과 풍도를 조사하고, 본 연구와 동시에 조사된 유해성 적조생물을 포함한 식물플랑크톤과의 상관관계를 연구하였다. 조사기간 중 종속영앙성 와편모류, 종피성 섬모충류 및 무피성 섬모충류의 출현 종 수와 풍도 모두 규조류가 우점한 시기에 최대값(풍도:종속영양성 와편모류는 11, 종피성 섬모충류는 10, 무피성 섬모충류는 12 cells $m\ell$$^{-1}$)을 기록한 반면, C. polykrikoides/G. impudicum가 우점하는 유해성 적조 발생 시기에는 낮은 값(풍도:종속영양성 와편모류는 1, 종피성 섬모충류는 0.5, 무피성 섬모충류는 2.4 cells $m\ell$$^{-1}$)을 나타냈다. 또한 규조류가 우점한 시기인 8월 10일과 11월 11일에 종피성 섬모충류와 무피성 섬모충류가 규조류와 비교적 높은 양의 상관관계를 나타내 이들이 규조류의 중요한 포식자로 작용했을 가능성이 높고, 동시에 규조류의 양적변화가 종피성 섬모충류와 무피성 섬모충류 풍도 변화에 큰 영향을 주었을 가능성이 높다. 독립-혼합영양성 와편모류가 우점한 9월 16일과 10월 18일에는 종속영양성 와편모류가 독립-혼합영양성 와편모류와 높은 상관관계를 나타냈는데, 10월 18일에 최고 우점종인 Noctiluca scintillans는 C. polykrikoides/G. impudicum의 유영속도가 현저히 떨어졌을 때 효과적으로 포식할 수 있는 능력을 가지고 있어, 당시에 운동성이 적은 C. polykrikoides/G. impudicum개체들의 포식자였을 가능성이 높다. 본 연구해역에서 조사된 종속영양성 와편모류, 종피성 섬모충류, 무피성 섬모충류의 최대풍도는 C. polykrikoides/G. impudicum이 우점하는 적조가 가장 먼저 연례적으로 발생하는 전남 고흥-여수 해역에서 1997년 8-9월 적조발생 전후에 조사된 최대풍도보다 상당히 낮게 나타났다. 본 연구의 결과는 연구해역의 우점 식물플랑크톤과 종속영양성 와편모류, 종피성 섬모충류, 무피성 섬모충류 간의 포식자-피식자 관계 규명을 위한 기초자료가 될 뿐 아니라, 나아가 서해안의 유해성 적조발생기작 연구에 있어서 원생동물성 포식자들의 역할 연구를 위한 유용한 자료로 활용될 것이다. We investigated the temporal variations in the heterotrophic dinoflagellates (hereafter HTD), tintinnid ciliates(TC), and naked ciliates(NC) from August to November 1999 in the coastal waters off the southern Saemankeum areas where a huge red tide dominated by Cochlodinium polykrikoides/Gymnodinium impudicum was first observed in 1998. We took water samples from 2-5 depths of 4 stations in each of the 5 cruises and then measured the species composition and abundances of HTD, TC, and NC The maximum species numbers and densities of HTD, TC, and NC(11, 12, and 10 cells $m\ell$$^{-1}$ , respectively) were observed when the density of diatoms was highest (August 10), while the lowest values (1.0, 0.5, and 2.4 cells $m\ell$$^{-1}$ , respectively) were found when the red tide dominated by C. polykrikoides/G. impudicum took placed (October 18). On August 10 and November 11 when diatoms dominated the abundance of phytoplankton, the correlation coefficients between TC, NC and diatoms were relatively high. However, On September 16 and October 18 when autotrophic+mixotrophic dinoflagellates(ATD+MTD) were abundant, the correlation coefficients between HTD and ATD+MTD were relatively high. The large HTD Noctiluca scintillans was the most dominant heterotrophic protists during the C. polykrikoides/G. impudicum red tide on October 18. N. scintillans has been known to feed on the prey cells when the swimming speeds of C. polykrikikoides/G. impudicum markedly reduced at the decline stage of the red tide. Therefore, N. scintillans could be effective grazers on C. polykrikoides/G. impudicum. The maximum densities of HTD, TC, and NC in the study area were fairly lower than those obtained in the waters off Kohung-Yeosu areas in the summer-fall, 1997. The results of the present study provide the basis of understanding predator-prey relationships between dominant phytoplankton and heterotrophic protists and the roles of the protist grazers in bloom dynamics in the waters off the western Korea.