보관 방법에 따른 Rotifer Brachionus plicatilis 내구란의 부화

윤주연 ( Joo Yeon Youn ),허성범 ( Sung Bum Hur ) 한국수산과학회(구 한국수산학회) 2011 한국수산과학회지 Vol.44 No.6

The rotifer Brachionus plicatilis is one of the most important food organisms in aquaculture. The resting eggs produced by mictic female rotifers are easily stored and hatched, making them useful as the starter for the mass culture of rotifers in marine larval culture. This study examined the optimum preservation method for resting eggs to ensure a high hatching rate. To produce resting eggs, the marine rotifer B. plicatilis was cultured with Nannochloris oculata (KMMCC 16). The resting eggs were harvested and cryopreserved using 5% and 10% methanol (MeOH), dimethylsulfoxide (DMSO), and glycerol as cryoprotectant agents (CPAs). The cryopreservation comprised slow or rapid freezing and the resting eggs were stored for one month in liquid nitrogen (-196˚C). The resting eggs were also dried at different temperatures (30, 40, and 50˚C) and for different times (1, 2, and 3 h). In general, the hatching rates of the resting eggs preserved with CPA were higher than those without CPA and the slow freezing method was better than the rapid freezing method. However, the optimum CPA concentration for the hatching rate of the resting eggs varied with the freezing method and kind of CPA, and the CPA also affected the viability of the resting eggs. Dried resting eggs had a high, rapid hatching rate over 80%. The moisture content of the resting eggs cryopreserved in liquid nitrogen affected the hatching rate. Drying at 30˚C for 1 hour resulted in a high hatching rate of the resting eggs. In conclusion, drying at 30˚C for 1 hour and preservation in liquid nitrogen with the slow freezing method, without CPA, is recommended for a high hatching rate (ca. 95%) of rotifer resting eggs.

온도와 염분이 Rotifer Brachionus plicatilis 와 B. rotundiformis 의 성장과 크기에 미치는 영향

윤주연 ( Joo Yeon Youn ),허성범 ( Sung Bum Hur ) 한국수산과학회(구 한국수산학회) 2011 한국수산과학회지 Vol.44 No.6

Rotifers of the genus Brachionus are commonly used as a live food for larval fish, and rotifers of different sizes are preferred according the mouth size of the fish. Rotifer species vary in size, and individual size can depend on the temperature and salinity of the rearing environment. We investigated the effects of temperature and salinity for two species, B. plicatilis (250-300 μm) and B. rotundiformis (100-220 μm). Two strains of B. plicatilis (CCUMP 36 and 48) and two strains of B. rotundiformis (CCUMP 51 and 56) were received from the Culture Collection of Useful Marine Plankton (CCUMP) at Pukyong National University and cultured with the green alga, Nannochloris oculata (KMMCC 16) from the Korea Marine Microalgal Culture Center (KMMCC). The growth and size of rotifers were examined at three water temperatures (16ºC, 24ºC, 32ºC) and four salinities (20 psu, 25 psu, 30 psu, 35 psu) under continuous light (40 μmolm-2s-1). The maximum density and growth rate of B. rotundiformis were greater than those of B. plicatilis . The lorica length of B. plicatilis ranged from 215.4 to 269.7 μm and from 154.9 to 206.6 μm for B. rotundiformis, depending on strain, temperature and salinity. Rotifers were smaller when cultured at high temperatures, regardless of salinity. B. rotundiformis preferred higher salinity than B. plicatilis . The results demonstrated that the size of rotifers could be controlled to some extent by temperature and salinity.

해양미세조류의 무균배양을 위한 항생제의 종류 및 최적 농도

윤주연,허성범,Youn, Joo-Yeon,Hur, Sung-Bum 한국조류학회(藻類) 2007 ALGAE Vol.22 No.3

This study was to determine the extent of bacteria contamination and resistance to various antibiotics used commonly in microalgal culture. Seven different dose levels of chloramphenicol, dihydrostreptomycin sulphate, neomycin, penicillin G, streptomycin sulphate, penicillin G + streptomycin sulphate, and penicillin G + streptomycin sulphate + chloramphenicol were added to each culture of microalgae. The lethal effects on microalgae and bacteria were the highest in chloramphenicol and the lowest in penicillin G. The axenic culture of bacillariophyceae and dinophyceae was more difficult than that of chlorophyceae and haptophyceae because of their complicate external morphology. The efficient antibiotics and their concentrations for axenic cultures varied with microalgal species. The optimum quantity for antibiotic treatments were 2,000 ppm of dihydrostreptomycin for Chlorella ellipsoidea, neomycin 500 ppm of Isochrysis galbana and Heterosigma ahashiwo, hloramphenicol 500 ppm of Cyclotella didymus, and dihydrostreptomycin sulphate and neomycin 6,000 ppm of Thalassiosira allenii.

Cloning and Characterization of Phosphoinositide 3-Kinase γ cDNA from Flounder (Paralichthys olivaceus)

Tae Hyug Jeong(정태혁),Joo Yeon Youn(윤주연),Keunho Ji(지근호),Yong Bae Seo(서용배),Young Tae Kim(김영태) 한국생명과학회 2014 생명과학회지 Vol.24 No.4

Phosphoinositide 3-kinase (PI3K)는 항산화 제어반응, 심근세포 성장, 및 세포 내 특수반응 뿐만 아니라 세포분화, 생장, 운동, 식균 및 내항작용, 세포 골격유지에 관여하는 등 세포 신호체계에서 핵심 역할을 하는 효소이다. PI3K는 세 그룹으로 나누어지며 type I PI3K는 leukocyte에서 우선적으로 발현되고 G-proteins의 βγ subunits에 의해서 활성화 된다. 본 연구에서는 넙치(Paralichthys olivaceus)의 PI3Kγ를 암호화하는 cDNA를 클로닝하였다. 넙치의 PI3Kγ는 1,341 bp 염기로 구성되는 한 개의 ORF를 가지며 이 단백질은 447 아미노산으로 구성되어있다. PI3Kγ는 zebrafish의 PI3Kγ와 89.6%, mouse와는 84.7%, Norway rat와는 84%, human의 PI3Kγ와는 74.9%가 아미노산 상동성을 나타내었다. PI3Kγ유전자의 대장균에서 발현을 위하여 pET-44a(+)-PI3K 재조합 DNA를 구축하여 대장균에서 발현시킨 결과 49 kDa의 재조합 단백질이 과발현 됨을 확인 할 수 있었다. His-tag affinity chromatography를 이용하여 PI3Kγ단백질을 순순 분리하였으며 wortmannin을 이용하여 PI3Kγ의 활성을 분석하였다. Phosphoinositide 3-kinase (PI3K) plays a central role in cell signaling and leads to cell proliferation, survival, motility, exocytosis, and cytoskeletal rearrangements, as well as specialized cell responses, superoxide production, and cardiac myocyte growth. PI3K is divided into three classes; type I PI3K is preferentially expressed in leukocytes and activated by βγ subunits of heterotrimeric G-proteins. In this study, the cDNAs encoding the PI3Kγ gene were isolated from a brain cDNA library constructed using the flounder (Paralichthys olivaceus). The sequence of the isolated PI3Kγ was 1341 bp, encoding 447 amino acids. The nucleotide sequence of the PI3Kγ gene was analyzed with that of other species, including Oreochromis niloticus and Danio rerio, and it turned out to be well conserved during evolution. The PI3Kγ gene was subcloned into the expression vector pET-44a(+), and expressed in the E. coli BL21 (DE3) codon plus cell. The resulting protein was expressed as a fusion protein of approximately 49 kDa containing a C-terminal six-histidine extension that was derived from the expression vector. The expressed protein was purified to homogeneity by His-tag affinity chromatography and showed enzymatic activity corresponding to PI3Kγ. The binding of wortmannin to PI3Kγ, as detected by anti-wortmannin antisera, closely followed the inhibition of the kinase activities. The results obtained from this study will provide a wider base of knowledge on the primary structure and characterization of the PI3Kγ at the molecular level.

규조류 Skeletonema pseudocostatum Medlin (Thalassiosirales, Bacillariohyta)의 형태적 특징과 분자계통학적 위치

한경하,이준,박준상,윤주연,김현정,곽경윤,오석진,신현호,Han, Kyong Ha,Li, Zhun,Park, Joon Sang,Youn, Joo Yeon,Kim, Hyun Jung,Kwak, Kyeong Yoon,Oh, Seok Jin,Shin, Hyeon Ho 한국환경생물학회 2020 환경생물 : 환경생물학회지 Vol.38 No.1

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. Morphology of a strain of unspecified Skeletonema species established from Korean coast was examined by light, fluorescence and scanning electron microscopy, and SSU(small subunit) and LSU(large subunit) rDNA of the strain were also sequenced. The specimen was characterized by solitary or short chains, and each cell contained 1-2 chloroplasts. The valve face was slightly convex, and the terminal fultoportula processes (TFPPs) were open and showed narrow distal ends that could be truncated or spiny with claw-like protrusions. The basal part of the TFPPs was tubular and oblique to the cell axis. The intercalary fultoportula processes (IFPPs) were also narrow, completely open, and joined in a 1 : 1 junction. Occasionally, one IFPP was connected with two opposing IFPPs. The morphological features of the specimen were identical to those of Skeletonema pseudocostatum. Molecular phylogeny based on SSU rDNA revealed that the Korean strain is nested within a clade comprising S. pseudocostatum and S. tropicum. However, based on D1-D2 LSU rDNA sequences, a clade including S. pseudocostatum and a Korean strain was separated from the S. tropicum clade. This indicates that the Korean strain can be identified as S. pseudocostatum. This species represents the first record from Korean coastal waters.