• 한국수산과학회지
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• 제33권6호
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• pp.597-599
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• 2000

This study was performed to find out the cryoprotectants for cryopreservation of trochophores and early D-shaped larvae of surf clam, Spisula sachalinensis. Dimethyl sulfoxide (DMSO), ethylene glycol, 1,2-propanediol and methanol were used as cryoprotectant Each cryoprotectant was made to 1.0 M, 2.0 M, 3.0 M with dilution of 0.2 M fructose and 0.2 M sucrose. The trochophoers and early D-shaped larvae were immersed in each preparation for 10 minutes to reach equilibration and cryopreserved in liquid nitrogen. Survival rates of post-thawed trochophores and early D-shaped larvae in 2.0 M DMSO with 0.2 M sucrose were the highest as $91.4{\%}\;and\;78.9{\%}$, respectively.

• 한국수산과학회지
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• 제36권2호
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• pp.157-162
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• 2003

Ultrastructure of germ cell during gametogenesis of surf clam, Spisula sachalinensis were investigated by electron microscopic observations. Oogonia are oval in shape and 5-6 ${\mu}m$ in diameter. They contain a large nucleus and have several mitochondria in the cytoplasm. Vitellogenic oocytes grew attached by a stalk to the germinal epithelium in the ovarian sac and their cytoplasm contained many yolk granules, lipid granules and mitochondria. Mature oocytes measuring 50-60 ${\mu}m$ in diameter have a nucleus containing an electron dense nucleolus, and a lots of yolk granules, lipid granules, mitochondria, rough endoplasmic reticulum and cortical granules were present in the cytoplasm. The surface of the plasma membrane in mature oocytes was formed of microvilli approximately 1.5 ${\mu}m$ long and enveloped in the vitelline layer. Spematogonia are oval in shape and about 5 ${\mu}m$ in diameter. Sprmatogonia develop into spermatocyte, spermatid and spermatozoon. The spermatozoon consisted of the head, midpiece and tail. The sperm head with diameter of about 1.5 ${\mu}m$ was ovoid, and contained the nucleus which consisted of acrosome. The four mitochondria encircled the centrosome in midpiece. The flagellum measuring about 40 ${\mu}m$ long had the classical 9+2 axoneme structure.

• 한국패류학회지
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• 제24권1호
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• pp.33-40
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• 2008

Ultastructural studies of oocyte degeneration and follicle cells in female Spisula sachalinensis are described for clams collected from Jumunjin, Gangwondo, Korea. The follicle cells playan integral role in vitellogenesis and oocyte degeneration by assimilating products originating from the degenerated oocytes (thus allowed the transfer of yolk precursors needed for vitellogenesis). The functions of the follicle cells include phagocytosis and intracellular digestion of products originating from oocyte degeneration. During the period of oocyte degeneration, follicle cells of this species probably have lysosomal systems for the breakdown and reabsorption of various phagosomes(phagolysosomes) in the cytoplasm for nutrient storage; this process has been observed in other bivalves.

• Fisheries and Aquatic Sciences
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• 제18권4호
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• pp.417-420
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• 2015

We investigated the relationship between viability and IGF-1 receptor (IGF-1R) activity in D-shaped and umbo larvae of the surf clam Spisula sachalinensis after treatment with vitrification solution (VS) or freezing. In a toxicity assay, VS1, containing 5 M dimethyl sulfoxide (DMSO), was very harmful to D-shaped and umbo larvae. However, VS2, containing 5 M ethylene glycol (EG), was not harmful to either larval stage. Although VS2 had a promising toxicity test outcome, none of the larvae survived vitrification. After immersion into VSs and freezing, IGF-1R ${\beta}$-subunits were detected in all larvae; however, tyrosine phosphorylation of intracellular ${\beta}$-subunits was detected only in the control and live groups. These results suggest that activation of IGF-1R may influence surf clam larvae viability.

• 한국발생생물학회지:발생과생식
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• 제5권1호
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• pp.35-38
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• 2001

동해안산 북방대합의 유생을 냉동보존하기 위한 적절한 유생단계를 선택하기 위해, 담륜자, 초기 D상 유생, 후기 B상 유생, 초기 각정기, 후기 각정기 유생에 대한 냉동실험을 실시하였다. 동해방지제로는 dimethyl sulfoxide와 ethylene g1yco1를 사용하였다. 동해방지제에 각 단계의 유생을 10분간 두어 평형상태에 달하게 한 다음, 냉동하여 액체질소에 보존하였다. 해동결과, 가장 높은 생존율을 나타낸 유생은 담륜자로서 동해방지제 2.0 M BMSO와 2.0 M ethylene glycol에서 생존율은 각각 97.4%와 85.0%였다. 발생이 진행된 유생일수록 생존율이 낮아지는 경향을 보였다.

• 한국수산과학회지
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• 제30권1호
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• pp.132-138
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• 1997

동해안 한해성 조개인 북방대합의 자원 증대를 위한 기초 자료를 얻기 위하여 1994년 3월부터 1995년 5월까지 주로 조직학적 방법에 의해 생식소의 발달과정과 생식주기를 조사하였다. 북방대합은 자웅이체로서, 생식소는 해부학적으로 소화맹낭과 족부 근육 사이에 위치하였다. 비만도는 1994년 6월에 0.19로 가장 높았으며 11월에 최소값을 보였다. 생물학적 최소형은 각장 50.0mm였으며, 80.0mm 이상의 대형개체에서도 $10\%$ 미만의 성적으로 미분화한 개체가 관찰되었다. 성숙한 난모세포의 크기는 $50\~60{\mu}m$였으며, 성숙기의 정소에서 정소란이 관찰되었다. 북방대합의 생식주기는 분열증식기 ($10\~1$월), 성장기 ($2\~4$월), 성숙기 ($4\~6$월), 산란기 ($6\~7$월) 및 휴지기 ($8\~9$월)의 연속적인 5단계로 구분되었다.

• 한국수산과학회지
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• 제35권2호
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• pp.135-139
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• 2002

이 연구에서 북방대합의 정자 운동성 및 수정률과 부화율 향상을 위한 수정방법을 조사하였다. 북방대합 원정액의 정자 농도는 $2.02{\times}10^{10}/mL$였으며, 채정 직후에는 원정액이나 해수중의 정액에서 모두 $96.0\%$의 정자가 전진운동을 하였다. 절개법으로 얻어진 알과 정자는 각각 채란 4시간 이내에, 채정 1시간 이내에 수정하는 것이 효과적이었다. 인공수정을 위한 알 1개에 대한 정자수는 10$\~$100개에서 수정률과 부화율이 모두 높았으며, 수정 후 1시간 이내에 세란하는 것이 효과적이었다. 최적의 수정 및 발생을 위한 알의 수용밀도는 100$\~$200 개/mL였다.

• 한국패류학회지
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• 제24권1호
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• pp.1-10
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• 2008

Spermatogenesis and the reproductive cycle in male Spisula sachalinensis were investigated by cytological and histological observations. The morphology of the spermatozoon has a primitive type and is similar to those of other bivalves in that it contains a short midpiece with four mitochondria surrounding the centrioles. But spermatozoon of this species has not axial rod and satellite body in the midpiece. The morphologies of the sperm nucleus type and the acrosome shape of this species have a globe-shape type and modified cap-like shape, respectively. The spermatozoon is approximately $40-45{\mu}m$ in length including the sperm nucleus length (about $1.35{\mu}m$), acrosome length (about $1.50{\mu}m$) and tail flagellum. The axoneme of the sperm tail flagellum consists of nine pairs of microtubules at the periphery and a pair at the center. The axoneme of the sperm tail shows a 9+2 structure. The spawning period of these species lasts from June to July, and the main spawning occurs in July when seawater temperatures are greater than $20^{\circ}C$. The male reproductive cycle of this species can be categorized into five successive stages: early active stage (October to January), late active stage (February to April), ripe stage (April to June), partially spawned stage (June and July), and spent/inactive stage (August to September).

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2002년도 국제심포지엄
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• pp.104-104
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• 2002

This study was performed to find out the optimal larval stage among trochophore, D-shaped and umbo stage larvae and the desirable protective additive such as fructose, glucose, sucrose and trehalose with cryoprotectant for cryopreservation of surf clam, Spisula sachalinensis larvae. Dimethyl sulfoxide and ethylene glycol were used as cryoprotectant and each cryoprotectant was made to 2.0 M with previous protective additives. The larvae were immersed in the preparations waited for 15 minutes to reach equilibration, and then frozen in a program freezer (-35$^{\circ}C$) and liquid nitrogen (-196$^{\circ}C$). The freezing rate of 1.0$^{\circ}C$ /min. was used for cryopreservation of trochophores before seeding temperature (-12$^{\circ}C$). The survival rate of frozen-thawed larvae increased as larval developing and that of umbo stage larvae was the highest as 96.1 ${\pm}$ 1.0%. The presence of lower concentration of disaccharides as sucrose or trehalose significantly enhanced survival rate when mixed with cryoprotectants (P<0.05). The results of our study indicate that desirable developmental stages of larvae and protective additive for cryopreservation are the umbo stage larvae and 0.2 M sucrose, respectively.

• 한국수산과학회지
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• 제35권5호
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• pp.504-511
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• 2002

본 연구는 개량조개과에 속하는 동죽, Mactra veneriformis, 개량조개, M chinensis, 북방대합, Spisula sachalinensis, 왕우럭, Tresus keenae을 대상으로 정자의 미세구조를 조사하였다. 조사한 4종 모두 primitive type의 정자를 가지고 있었다. 첨체모양은 4종 모두 유사한 형태로 첨체의 앞쪽은 전자밀도가 낮은 부분 (elp)이고, 첨체의 뒤쪽은 전자밀도가 높은 부분 (edp)로 나누어지는 변형된 모자모양이다. 4종의 정자의 핵 모양은 상대적으로 차이가 있어 구분이 가능하며, 특히 Mactra 속의 2종은 핵의 모양이 서로 유사하다. 그리고 정자의 중편부를 구성하고 있는 미토콘드리아수는 4종 모두 4개로 나타났다. 개량조개 과 조개의 정자형태는 종 특이성을 가지고, 특히 첨체는 다른 과의 조개류와 다른 과수준의 특이성으로 판단된다.