• Korean Journal of Animal Reproduction
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• v.23 no.4
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• pp.323-331
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• 1999

The effects of insulin-like growth factor-I (IGF-I) and cumulus cells during in vitro maturation in porcine oocytes were examined. When follicular oocytes were cultured in medium with different concentrations of IGF-I, maturation rates were 60, 61 and 62 and 72% for 0, 15 and l0ng/$m\ell$ IGF-I. In medium with 10ng/$m\ell$ IGF-I, maturation rates were not significantly difference between oocytes with (68%) and without (52%) cumulus cells during the culture. In medium with-out IGF-I, however, the maturation rates in oocytes with cumulus cells (63%) was significantly (P＜0.05) higher than oocytes without cumulus cells (32%). On the other hand, when IGF-I was added for first 24 h period or later 24 h period of culture, maturation rates were higher in oocytes with (61 and 49%) that than without (49 and 45%) cumulus cells. In experiment used medium without fetal calf serum (FCS) and porcine follicular fluid (PFF), the maturation rates in oocytes with cumulus cells for 48 h (48 and 67%) or first 24 h (46 and 63%) period after culture were significantly (P＜0.01) higher than in oocytes without cumulus cells (16 and 18%) in the presence or absence of IGF-I. These results indicated that cumulus cells is essential on maturation in vitro in porcine oocytes, but IGF-I can promote oocytes maturation of oocytes without cumulus cells in medium with FCS and PFF.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.62-62
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• 2003

최근 연안 자원이 급격하게 감소하고 있고 새로운 양식 대상종으로 평가되고 있는 말쥐치의 대량 종묘생산을 위해서는 수정난 대량확보와 자어기 먹이생물 구명 등의 문제점이 해결되어야 한다. 본 연구자들은 우선 호르몬 처리에 의한 산란유도, 조기성숙유도에 의한 조기산란유도 및 수정난 확보방법을 개발하고, 위내용물 분석을 통한 자어의 초기먹이생물을 구명하고자 하였다. 산란유도를 위하여 hCG, LHRH-a 및 hCG+LHRH-a를 다양한 농도로 처리하여 실험한 결과 모든 실험구에서 67~76%의 수정률을 나타내었으나, 대량의 성숙란을 얻지는 못하였다. 따라서 본 종의 산란특성이 다회성인 점을 감안한다면 500 g 전후의 친어 200~300마리를 1개의 수조에 수용하여 자연산란된 수정란을 수거하는 것이 좋을 것으로 판단되었다. 평균 450 g 정도의 말쥐치 친어를 12월부터 6개월동안 천천히 수온을 상승시켜 자연산란을 유도한 결과, 자연산란기 (6월)보다 2개월 빠른 4월 15일(17$^{\circ}C$로 가온한 지 15일)에 첫 산란이 이루어졌고 1개월간 지속되었다. 초기 사육환경을 구명하기 위한 실험에서는 일반적으로 해산어 종묘 생산에 이용하는 클로렐라＋rotifer 실험군이 클로렐라 단독, 규조류 단독, 규조＋rotifer, 녹조＋copepods등이 번식된 환경보다 생존율에 있어 월등히 높은 결과를 나타내었다. 위 내용물 분석에 의한 사육기간 중 섭식한 주요 먹이생물종은 부화 후 5일부터 20일째까지는 rotifer egg, 부화 10일째는 rotifer egg와 small rotifer, 부화 20일째는 rotifer, Artemia sp., copepods, 부화 25일째부터는 copepods였다. 초기성장은 부화직후 전장 1.95 mm였던 것이 10일째는 2.96 mm, 20일째는 3.89 mm, 30일째는 12.9 mm, 50일째는 35.1 mm를 나타내었다. 그러나 말쥐치 자ㆍ치어가 성장함에 따라 발생하는 지속적인 폐사와 종묘의 수송시 발생하는 폐사를 줄일 수 있는 방법이 추후에 해결되어야 할 것으로 사료된다.

• The Korean Journal of Ecology
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• v.28 no.5
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• pp.281-286
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• 2005

The ripe unfertilized eggs of Acheilognathus signifer were elliptical shape and baggily swollen toward animal pole. The size of fertilized eggs were $2.19{\pm}0.01$ mm in long axis and $1.85{\pm}0.08$ mm in short axis and oil globe were not observed. The zona radiata of A. signifer had the structure of regular fibrilar net and the diameter of outer opening micropyle was about $2.5{\mu}m$ and that of inner opening micropyle was about $1.5\sim2.0{\mu}m$. Development of fertilized eggs in A. signifer was proceeded in inclining position of animal pole and hatched in 49 hours under $20{\pm}1^{\circ}C$. The yolk sac was absolutely absorbed in 21 days after hatching.

• Korean Journal of Ichthyology
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• v.11 no.2
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• pp.126-133
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• 1999

Ultrastructure of the zona radiata and the micropyle of ripe eggs in the rainbow trout (Oncorhynchus mykiss), catfish (Silurus asotus) and loach (Misgurnus anguillicaudatus) were examined by light, scanning and transmission microscopes. The egg micropyle of rainbow trout and catfish consists of a funnel-shaped vestibule and a tapered canal transversing the zona radiata. The micropyle of rainbow trout and catfish showed the similar structure with flat pit and long canal. The micropylar wall showed the clockwise spiral structure in rainbow trout. The micropyle of the loach showed the type with a hollow pit leading into a short canal and the micropylar wall showed the counterclockwise spiral structure. There are numerous and various size pores at the surface area around the opening in every experimented fish. Interconnecting ridges were observed in the unfertilized eggs of every fish.

• Development and Reproduction
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• v.12 no.2
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• pp.125-132
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• 2008

Melatonin (N-acetyl-5-methoxytryptamine), a major hormone of pineal gland in vertebrates, is known to be associated with regulation of the dynamic physiological functions in general and has some functions on reproduction in the ovarian follicles in particular. And its antioxidant properties as a scavenger are also reported. The aim of this study was to investigate the effect of melatonin on the in vitro maturation of mouse germinal vesicle (GV)-stage oocytes. Oocyte maturation, apoptosis, and mRNA expression of melatonin receptor were analyzed in the cumulus cell-enclosed oocytes (CEOs) cultured with melatonin for 18 h. The CEOs were obtained from 3 wk-old ICR female mice cultured in media with 0, 0.1 nM, 10 nM, or 1,000 nM melatonin for 18 h. And then the extrusion of the first polar body was assessed to evaluate the maturation rate. The apoptosis and mRNA expression of melatonin receptor (Mtnr1-a and Mtnr1-b) in cumulus cells of each group were measured by TUNEL assay, ELISA, and real time RT-PCR after in vitro maturation(IVM). The addition of melatonin in the IVM medium significantly improved nuclear maturation of the mouse GV oocytes and the highest maturation rate were obtained from the group treated with 1,000 nM melatonin. Apoptosis was not detected in IVM oocytes, but detected in cumulus cells. And cumulus cells treated with 1,000 nM melatonin exhibited significantly lower apoptosis. In the group treated with 1,000 nM melatonin, the expression of melatonin receptor mRNA was decreased in CEOs. In conclusion, melatonin has a potentially important role for regulating oocyte maturation and reduces the apoptosis of cumulus cells in vitro.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.3
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• pp.338-346
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• 1995

Studies on activities of hepatocytes and changes of protein and total RNA contents in liver and muscle tissues associated with the gonadal maturation were performed using the adult rockfish, Sebastes schlegeli collected monthly from the adjacent waters at Poryong, Chungnam, Korea. Hepatosomatic index (HSI) of female increased from September and reached the maximum value (2.58) in February (growing stage of ovary). HSI of male began to increase from October (early maturation stage) and revealed the maximum value (3.20) in April (recovery stage). During the period of yolk formation in oocyte, the amount of glycogen particles and lipids in the hepatocytes of female gradually decreased, but total RNA contents increased. In the hepatocytes of male, a number of lipid droplets remained until the mature stage of testis. With the gonadal development of both sexes, granular endoplasmic reticula (Er) became abundant in the hepatocyte. These Ers might be supposed to have the leading role for the syntheses of protein and vitellogenin in the cytoplasm of the hepatocytes. Protein and total RNA contents in the liver and muscle tissues of female began to increase from January (growing stage) and reached the maximum value in early April (maturation stage), and then decreased in late April (gestation stage). In male, their contents began to increase from October (early maturation stage), thereafter reached the maximum value in December (maturation and copulation stage), and decreased in January (degeneration stage).

• Applied Microscopy
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• v.40 no.3
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• pp.169-176
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• 2010

Black molly (Poecilia sphenops) and sailfin molly (Poecilia latipinna) are a teleost belonging to Poeciliidae. The spermatogenesis between two species were investigated by light and electron microscope. The whitish testes of both black molly and sailfin molly were located between intestine and air bladder. The size of testis was major axis 7 mm, minor axis 2 mm. The testis contained numerous testicular cysts. In both black molly and sailfin, primary spermatocytes were comparatively large ellipsoidal, and mitochondria showed a marked development. The secondary spermatocyte was smaller than that of primary spermatocyte, highly condensed according to their development. The nucleus with electron-dense was round shape and flagella started to be formed. In spermiogenesis, chromatin was more condensed. The mitochondria were rearranged along the tail. The number of mitochondria was 2 to 4 in cross section and 8 to 10 in longitudinal section. The head of mature sperm was long cone shape and had not acrosome. The microtubules of flagella were arranged 9+2 structure. Also, the tail of sperm have lateral fins. In conclusion, spermatogenesis and sperm morphologies of these two species were same. These morphological similarity seems to be an indication of the Poeciliidae.

• Journal of Aquaculture
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• v.10 no.1
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• pp.25-32
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• 1997

Develoment precess and characteristics of eggs of the geoduck clam, Panope japonica are reporting in this study. Eggs and sperm were excised from gonad, artificially fertilized in an aquarium, reared under various temperature regimes, and record and record the larval period and the time need to reach a certain larval stage from ferilization. Unfertilized eggs of P. japonica appeared to be oval with a mean diameter of $70\mu$m and they became spherical after fertilization. The eggs of P. japonica can be classified as demersal. At a constant water temperature of $ 11^{citc}C$, it took 4 hours form fertilization to become four-cell stage, two days to become trochophore larvae, three days to become D-shape larvae, twenty-three days to become umbo stage, and thirty-six days to become fully grown veliger ready form settlement. A negative correlation was observed between the water temperature and the larval period of P. japonica. From fertilization to D-shape larvae, it took five days at 8$^{\circ}C$, while it was only two days to become D-shape larvae at $ 17^{citc}C$. Time required to D-shape larvae from fertilization was proportional to temperature, and the relationships were expressed as follows : To 8-cell stage, 1/t=0.0209 w-0.1167 (r=0.9967) To blastula stage, 1/t=0, 0055 w-0.0192 (r=0.9825) To trochophore stage, 1/t=0.0034 w-0.0155 (r=0.9907) To D-shape larvae stage, 1/t=0.0014 w-0.0023 (r=0.9843) (t, time in hours ; w, water temperature) Bioligical minimum temperature for egg development was calculated as 3.82$^{\circ}C$ in average.

• Journal of Aquaculture
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• v.15 no.1
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• pp.23-29
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• 2002

To develop techniques for the production of artificial seedling of Corbicula japonica, protocols for induction of spawning and larval development were developed. During the assumed spawning period of August to mid-September, attempts were first made to induce spawning by gonadal incision and UV-irradiation but all in vain. At the end of August, elevated thermal induction evoked 90 % positive response in animals maintained at $3\textperthousand$ salinity. Immersion in (1/1000~3/1000 N) ammonium hydroxide ($NH_4$OH) also induced spawning in 15~45%) of the treated animals at $3\textperthousand$ salinity. Fertilized eggs measured 86$\mum. At 23.0~24.5$^{\circ}C$, the fertilized egos developed into 4-cell stage embryos within 2 hours, trochophores 15 hours, D-shaped larvae 2 days, umbo 9 days and fully grown veligers, ready to infiltrate into the sediment, within 16 days.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2010.05a
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• pp.13-13
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• 2010

복주머니난(Cypripedium)속 식물은 우리나라에 광릉요강꽃을 비롯하여 털복주머니난, 흰털복주머니란, 복주머니란, 노랑복주머니란등 5종이 분포하는 것으로 알려져 있다. 광릉요강꽃과 털복주머니란 두 종은 환경부에서 지정한 멸종위기 식물 1급과 2급에 지정되어 보호를 받고 있고 나머지 3종은 제도적으로도 보호를 받지 못하는 실정이다. 본 연구에서는 충분히 성숙한 털복주머니난과 복주머니난의 종자에 NaOCl처리를 하여 발아율을 향상시킬수 있었는데 이러한 전처리가 발아에 미치는 원인에 대한 연구를 실시하였다. 털복주머니란의 무균적인 종자발아는 1.0% NaOCl 처리구에서 70% 이상의 종자발아율을 보였으며, POM배지가 MS배지보다 신초분화가 양호했다. GA3와 활성탄(Activated charcoal)의 혼합첨가는 신초증식에 효과적이었다. 신초분화 후 저온처리는 신초의 증식 율을 증가시켰다. 한편 NaOCl 농도(0, 1, 3, 5, 10%)와 NaOCl 처리시간(0, 5, 15, 30, 45, 60분)에 따라서 복주머니란의 종자발아를 확인한 결과, NaOCl 1%를 30분간 처리하였을 때 가장 높은 발아율을 나타냈다. NaOCl을 처리하여 종자의 종피상태를 SEM과 TEM으로 관찰한 결과 NaOCl의 처리는 종피 세포벽의 부분적 해리 및 작은 구멍을 만들게 하였는데 이러한 종피의 물리화학적 변화가 물과 양분의 이동을 원활히 하여 종자의 발아를 촉진하는 것으로 사료된다. 복주머니난의 신초분화에 미치는 casein과 활성탄의 효과를 알아본 결과 casein 200 mg/L와 활성탄 200 mg/L를 혼합 첨가한 실험구에서 가장 높은 신초분화율을 보였다. 토양순화 후 생존률은 극히 저조했으며 30 개체중에 5 개체만이 다음해 어린동아를 싹틔우는 것을 확인 하였다. 본 결과들을 종합하여 보면 멸종위기식물, 특히 털복주머니란과 복주머니란의 조직배양을 통해서 서식지외 보존방안(기내증식)에 관해 가능성을 제시하였다고 생각되어 진다.