• 환경생물
• /
• 제39권2호
• /
• pp.236-244
• /
• 2021

Unarmored dinoflagellates, in the family Kareniaceae, include harmful or toxic bloom-forming species, which are associated with massive fish kills and mortalities of marine organisms worldwide. The occurrence and distribution of the toxigenic species in the family Kareniaceae were investigated in the brackish and coastal waters of Korea between July 2018 and October 2020. During the survey, we collected seven newly recorded species; Karenia papilionacea, Karlodinium digitatum, Karl. veneficum, Karl. zhouanum, Takayama acrotrocha, T. helix, and T. tasmanica. A total of fifteen strains of the seven taxa were successfully established as clonal cultures and examined using LM, SEM, and molecular phylogeny inferred from LSU rDNA sequences. Herein, we present the taxonomic information, morphological features, and molecular phylogenetic positions of the unrecorded dinoflagellate species collected from Korean coastal waters.

• 환경생물
• /
• 제39권4호
• /
• pp.573-580
• /
• 2021

Unarmored and thin-walled dinoflagellates were collected from brackish and coastal waters of Korea from August 2019 to August 2021. A total of 10 species belonging to orders Sussiales and Gymnodiniales were isolated and established as clonal cultures. Of them, five species (Biecheleria brevisulcata, Lepidodinium chlorophorum, Karlodinium decipiens, Kirithra asteri, and Wangodinium sinense) are newly recorded in Korea and examined using a light microscope (LM) and a scanning electron microscope (SEM). Their molecular phylogeny was inferred from LSU rDNA sequences. Here, we present taxonomic information, morphological features, and molecular phylogenetic positions of these unrecorded dinoflagellate species.

• 한국해양학회지:바다
• /
• 제24권2호
• /
• pp.236-248
• /
• 2019

본 연구는 2017년 4월 춘계 제주 연안에서 총 7개의 정점(협재, 이호테우, 함덕, 성산, 표선, 남원, 사계)을 선정하여 해조류에 부착하여 서식하는 유독 착생 와편모류 Ostreopsis의 출현양상을 조사하고 분자계통학적 분석을 실시하였다. 본 연구 해역의 표층 수온은 $15.7^{\circ}C-18.3^{\circ}C$의 범위를 보였으며, 염분은 33.4-34.9의 범위로 나타났다. 각 연구 정점에서 채집된 전체 13종의 해조류 가운데 8종에서 Ostreopsis가 출현하였으며, 정점 6에서 출현한 홍조식물 참지누아리(Grateloupia filicina)에서 해조류 단위 무게당 Ostreopsis의 출현밀도($cells\;g^{-1}$)가 $157.5cells\;g^{-1}$로 가장 높은 농도로 출현하였다. Ostreopsis가 출현한 4개의 연구정점에서 분리한 종주들의 LSU rDNA D8/D10 영역의 염기서열은 모두 100% 동일한 것으로 나타났다. LSU rDNA 염기서열 정보를 이용한 분자계통수에서 이들은 모두 Ostreopsis cf. ovata의 잠재종(cryptic species)으로 알려진 Ostreopsis sp. 1의 분기군에 속하는 것으로 나타났다. Ostreopsis sp.1 종주를 이용하여 수온과 염분에 따른 생장 반응을 측정한 결과, $10-30^{\circ}C$의 광범위한 수온과 20-35의 염분 범위에서 뚜렷한 생장을 나타내었고, 수온 $25^{\circ}C$와 염분 30에서 $0.49d^{-1}$의 최고 생장률을 나타내었다. 또한, 수온 $10^{\circ}C$의 저온에서도 염분 35에서 뚜렷한 생장을 보여, 이들은 온대 해역에서 적응하여 정착한 종으로 판단된다.

• ALGAE
• /
• 제28권4호
• /
• pp.307-330
• /
• 2013

The genus Cryptomonas is easily recognized by having two flagella, green brownish color, and a swaying behavior. They have relatively simple morphology, and limited diagnostic characters, which present a major difficulty in differentiating between species of the genus. To understand species delineation and phylogenetic relationships among Cryptomonas species, the nuclear-encoded internal transcribed spacer 2 (ITS2), partial large subunit (LSU) and small subunit ribosomal DNA (rDNA), and chloroplast-encoded psbA and LSU rDNA sequences were determined and used for phylogenetic analyses, using Bayesian and maximum likelihood methods. In addition, nuclear-encoded ITS2 sequences were predicted to secondary structures, and were used to determine nine species and four unidentified species from 47 strains. Sequences of helix I, II, and IIIb in ITS2 secondary structure were very useful for the identification of Cryptomonas species. However, the helix IV was the most variable region across species in alignment. The phylogenetic tree showed that fourteen species were monophyletic. However, some strains of C. obovata had chloroplasts with pyrenoid while others were without pyrenoid, which used as a key character in few species. Therefore, classification systems depending solely on morphological characters are inadequate, and require the use of molecular data.

• ALGAE
• /
• 제33권1호
• /
• pp.21-35
• /
• 2018

The phototrophic dinoflagellate genus Scrippsiella is known to have a worldwide distribution. Here, we report for the first time, the occurrence of Scrippsiella lachrymosa in Korean waters. Unlike the other stains of S. lachrymosa whose cultures had been established from cysts in the sediments, the clonal culture of the Korean strain of S. lachrymosa was established from motile cells. When the sulcal plates of S. lachrymosa, which have not been fully described to date, were carefully examined using scanning electron microscopy, the Korean strain of S. lachrymosa clearly exhibited the anterior sulcal plate (s.a.), right sulcal plate (s.d.), left sulcal plate (s.s.), median sulcal plate (s.m.), and posterior sulcal plate (s.p.). When properly aligned, the large subunit (LSU) rDNA sequence of the Korean strain of S. lachrymosa was ca. 1% different from those of two Norwegian strains of S. lachrymosa, the only strains for which LSU sequences have been reported. The internal transcribed spacer (ITS) rDNA sequence of the Korean strain of S. lachrymosa was also ca. 1% different from those of the Scottish and Chinese strains and 3% different from those of the Canadian, German, Greek, and Portuguese strains. Thus, the Korean S. lachrymosa strain has unique LSU and ITS sequences. The abundances of S. lachrymosa in the waters of 28 stations, located in the East, West, and South Sea of Korea, were quantified in four seasons from January 2016 to October 2017, using quantitative real-time polymerase chain reaction method and newly designed specific primer-probe sets. Its abundances were >$0.1cells\;mL^{-1}$ at eight stations in January and March 2016 and March 2017, and its highest abundance in Korean waters was $26cells\;mL^{-1}$. Thus, S. lachrymosa has a nationwide distribution in Korean waters as motile cells.

• 환경생물
• /
• 제38권1호
• /
• pp.21-29
• /
• 2020

Skeletonema pseudocostatum의 세포는 규산질 성분의 돌기에 의한 사슬 형태로, 길이는 6~17.3 ㎛였고, 엽록체는 세포 당 1~2개를 포함하고 있었다. 주사전자현미경 관찰결과 Skeletonema 종을 구분할 수 있는 가장자리 받침돌기끝(terminal fultoportula process)은 끝이 갈라지거나, 갈고리 모양이었고, 길이가 1.67±0.5 ㎛이고, 개각의 가장자리에 위치해 있으며, 개수는 8.10±1.1개로 개각의 크기에 따라 다양하게 나타났다. 말단세포 입술돌기(terminal rimoportula process)는 두꺼운 원통형의 나팔관 모양으로, 개각의 중앙 근처에 위치하였고, 길이는 1.1±0.6 ㎛였으며, 개수는 1개였다. 연결세포 받침돌기(intercalary fultoportula process)는 대부분 1 : 1 결합으로 서로 맞물려 있는 형태였고, 1 : 2 결합도 종종 발견되었다. 계통분석 결과는 형태적 특징이 유사한 종 간의 유전학적 거리가 가깝다는 것을 나타냈고, 지리적 기원이 다른 동일 종의 경우, 유전적 차이를 보이지 않았다. 이는 S. pseudocostatum은 지리적 위치와 상관없이 유전적 차이가 나타나지 않는 단일계통(monophyly)이라는 것을 의미한다.

• Animal cells and systems
• /
• 제15권4호
• /
• pp.315-324
• /
• 2011

The actiniarian sea anemone, Entacmaea quadricolor, and the scleractinian coral, Alveopora japonica, host symbiotic dinoflagellates belonging to the genus Symbiodinium (Freudenthal). We studied the host-symbiont specificity of these two anthozoan hosts in the northwestern Pacific Ocean. Symbionts within the two hosts were identified using partial large subunit (LSU) ribosomal DNA (rDNA) and complete internal transcribed spacers (ITS) 1 rDNA regions. The host, E. quadricolor, was identified using the partial LSU rDNA molecular marker. Genetic analysis showed that E. quadricolor only harbors dinoflagellates belonging to subclade C1/3 of the genus Symbiodinium. Moreover, no genetic variation was detected among the symbionts of E. quadricolor within the study region (Korea and Japan), even though the two distant sites were separated by more than 1000 km, at collection depths of 1 m in shallow and 13-16 m in deep water. Whilst scleractinian corals host multiple Symbiodinium clades in tropical waters, A. japonica, sampled over a wide geographical range (800 km) within the study region, only hosts Symbiodinium sp. clade F3. The high specificity of endosymbionts in E. quadricolor and A. japonica within the northwestern Pacific Ocean could be accounted for because symbiotic dinoflagellates within the host anemones appear to be acquired maternally, and the Kuroshio Current might affect the marine biota of the northwestern Pacific. However, the consistency of the symbiotic relationships between these two anthozoan hosts and their endosymbionts could change after climate change, so this symbiotic specificity should be monitored.

• ALGAE
• /
• 제37권3호
• /
• pp.185-204
• /
• 2022

The genus Coolia A. Meunier 1919 has a global distribution and is a common member of epiphytic dinoflagellate assemblages in neritic ecosystems. Coolia monotis is the type species of the genus and was the only known species for 76 years. Over the past few decades, molecular characterization has unveiled two species complexes that group morphologically very similar species, so their limits are often unclear. To provide new knowledge on the biogeography and species composition of the genus Coolia, 16 strains were isolated from Bahía de La Paz, Gulf of California. The species were identified by applying morphological and molecular approaches. The morphometric characteristics of all isolated Coolia species were consistent with the original taxa descriptions. Phylogenetic analyses (large subunit [LSU] rDNA D1 / D2 and internal transcribed spacer [ITS] 1 / 5.8S / ITS2) revealed a species assemblage comprising Coolia malayensis, C. palmyrensis, C. tropicalis, and the C. cf. canariensis lineage. This is the first report of Coolia palmyrensis and C. cf. canariensis in Mexico and C. tropicalis in the Gulf of California. Our results strengthen the biogeographical understanding of these potentially harmful epiphytic dinoflagellate species.

• 한국균학회지
• /
• 제51권3호
• /
• pp.155-165
• /
• 2023

In this study, we isolated several fungal strains from filtered water and sediment collected from rivers and streams. The strains were identified by molecular phylogenetic analyses of rDNA sequences (internal transcribed spacer [ITS], large subunit of ribosomal DNA [LSU]). The morphological characteristics of the fungi were investigated using microscopy, and the culture characteristics of fungi grown on several media were examined. We identified four species previously unknown in South Korea, namely, Dissophora globulifera, Linnemannia exigua, Mortierella rishikesha and Umbelopsis autotrophica.

• Mycobiology
• /
• 제40권2호
• /
• pp.94-99
• /
• 2012

During an investigation of fungi from an elm tree infested with bark beetles in Korea, one isolate, DUCC401, was isolated from elm wood. Based on morphological characteristics and phylogenetic analysis of the internal transcribed spacer and 28S rDNA (large subunit) sequences, the isolate, DUCC401, was identified as Mariannaea samuelsii. Mycelia of the fungus grew faster on malt extract agar than on potato dextrose agar and oatmeal agar media. Temperature and pH for optimal growth of fungal mycelia were 25oC and pH 7.0, respectively. The fungus demonstrated the capacity to degrade cellobiose, starch, and xylan. This is the first report on isolation of Mariannaea samuelsii in Korea.