• 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.

• 한국발생생물학회:학술대회논문집
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• 한국발생생물학회 2003년도 제3회 국제심포지움 및 학술대회
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• pp.72-72
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• 2003

The present study examined the possibility of cryopreservation of the D-shaped and umbo larvae of arkshell (Scapharca broughtonii), in terms of the survival rates after freezing and thawing. D-shaped and umbo larvae of arkshells were obtained from a shellfish farming on Yosu city. The average shell lengths were $93.3 \pm 10.1 \mu$m and $201.7 \pm 13.5 \mu$, respectively. Five cryoprotectants (CPAs), dimethyl sulfoxide (DMSO), glycerol, ethylene glycol (EG), propylene glycol (PG), and methanol, were tested at the concentrations of 1.5, 2.0 and 2.5 M. After larvae suspended in CPAs, cryoprotectants were loaded in 0.5 ml straws at a larval density of 50-100 larvae per straw, and epuilibrated for 10 and 20 minute at room temperature ($23^{\circ}C$), repectively. Straws were cooled at a rate of $1^{\circ}C$/min from $0^{\circ}C$ to $-12^{\circ}C$, held for 5 min at $-12^{\circ}C$, and then cooled at $2^{\circ}C$/min to $-35^{\circ}C$ and equilibrated for 5 min followed by plunging in liquid nitrogen. After storage in liquid nitrogen for 1 day, straws were thawed in a $30^{\circ}C$ water. As soon as straws were observed to melt, larvae were diluted with an equal volume of ASW and then washed twice with a large volume of ASW at an interval of 2 min to unload the CPAs. The results showed that after equilibration for 10 and 20 minute at room temperature, no larvae survived using methanol as CPAs, and it was observed that larval shells all open slightly, and larval flesh broke down and slopped over the shells. The highest survival rates (D-shaped larvae: 77.6%, umbo larvae: 59.3%) were obtained with 2M DMSO, and 1.5M glycerol yielded survival rates of 53.8% for D-shaped larvae and 37.5% for umbo larvae. The surviving D-shaped larvae showed active rotary motion and perfect membrane integrity and cytoplasmic normality, and the vigorous movement of veliger cilia was observed inside the closed shells. The breakdown of tissue occurred in the abnormal larvae, and the isolated cell often run out of shells.

• 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.

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2003년도 제3회 발생공학 국제심포지움 및 학술대회
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• pp.72-72
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• 2003

• 한국수산과학회지
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• 제18권5호
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• pp.471-476
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• 1985

우리나라 굴 양식의 중심해역인 한산만에서 효율적인 채묘예보를 기하기 위한 방안으로써, 이 수역에 발생한 굴 부유유생을 대상으로 하여 각 유생의 발육단계별 출현상황과 생존율을 조사하였다. 1984년 6월 13일 부터 10월 16일까지의 조사기간 중 크기가 약 $72{\times}61{\mu}m$의 D 형 유생은 7월 16일과 9월 20일에 각각 출현 Peak가 있었으며, $189{\times}217{\mu}m$의 umbo 형 유생은 7월 21일과 9월 25일에, $303{\times}308{\mu}m$의 성숙유생은 7월 28일과 9월 30일에 각각 Peak가 있었다. D형유생에서 umbo 형 유생으로 되는데는 약 5일이 걸렸으며, 순간사망률은 0.24, 일간생존율은 0.78, 일간사망률은 0.22, 평균생존율은 약 $29.38\%$였다. umbo형유생에서 성숙유생으로 되는데는 $5{\sim}7$일 소요되었으며, 순간사망률은 0.15, 일간생존율은 0.86, 일간사망률은 0.14, 평균생존율은 약 $38.54\%$였다. D형유생의 발생에서 채묘의 대상이 되는 성숙유생으로 되는데는 $10{\sim}12$일 걸렀으며, 이 기간중의 평균생존율은 약 $11.32\%$였다.

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2002년도 국제심포지엄
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• pp.103-103
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• 2002

This study was conducted to investigate cryopreservation of pearl oyster, Pinctada fucata martensii larvae. Four cooling rates (-0.25, -0.5, -0.75 and -1.0$^{\circ}C$/min.) were used to examine a proper cooling rate during cryopreservation of trochophores before seeding temperature (-12$^{\circ}C$). Seven developmental stages (early and late trochophores, early and late D-shaped larvae and early, middle and late umbo stage larvae) and different sugars (fructose, glucose and sucrose) were used to investigate optimal larval stage and effective sugar in cryopreservation of larvae. The survival rates of frozen-thawed trochophores increased at cooling rate of -1.0$^{\circ}C$/min. As larval developing, survival rate of frozen-thawed larvae increased, except umbo stage larvae, and especially late D-shaped larvae highly survived as 91%. Addition of sugar revealed positive effect on cryopreservation in this experiment and 0.2 M glucose and sucrose mixed with 2.0 M dimethyl sulfoxide significantly enhanced survival rate of larvae (P<0.05). The results of our study indicate that desirable cooling rate, developmental stages of larvae and effective sugar far cryopreservation of pearl oyster, P. fucata martensii larvae are -1$^{\circ}C$/min, late D-shaped larvae and 0.2 M glucose and sucrose, respectively.

• 한국발생생물학회지:발생과생식
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• 제17권4호
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• pp.337-343
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• 2013

Post-thawed larval rearing in Pacific oyster Crassostrea gigas was performed to investigate the survival rate with time course in three kinds of larvae cryopreserved. The highest survival rate and larval activity index (LAI) of post-thawed larvae were obtained from the permeation in 0.2 M sucrose and 2.0 M ethylene glycol (EG) at $-1^{\circ}C/min$ in freezing speed showing the survival rates just after thawing of 63.8% in trochophore, 84.1% in D-shaped veliger and 56.3% in early umbo veliger. In post-thawed larval rearing with food supply, the larvae lasted their lives until 24 hours in trochophore, 75 hours in D-shaped veliger and 57 hours in early umbo veliger. The results suggested that each larval stage post-thawed revealed no more further development to subsequent respective stage.

• 한국패류학회지
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• 제15권2호
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• pp.115-119
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• 1999

We investigated the processes of egg and larval developments for aquaculture technique development of seedling production fo the flat oyster, Ostrea denselamellosa. Teo flat oyster of larviparous type was different from the pacific oyser (ovivarous type) because their larvae (trochophore and prodissoconch larvae) in the gill released into the seawater. The process of egg development was observed by artificial fertilization at $25^{\circ}C$, using a dissecting method. The sizes of Unfertilized eggs ranged from 80 to 90 $\mu\textrm{m}$ and fertilized eggs with globule-shape was 90-100 $\mu\textrm{m}$. The Polar body appeared after fertilization and egg cleavage began within 1 hour, reaching the blastula stage after 10 hours. The trochophore in the gill appeared 2-3 days after fertilization and grew to the prodissoconch larvae (130 140 $\mu\textrm{m}$) having a complete shell after 1-2 days. The shell of prodissoconch larvae grew to 205 220 $\mu\textrm{m}$ after 10 hours, and then they became umbo stage larvae showing oval in shape. The velum of umbo stage larvae was degenerated about 17-20 days after fertilization and grew into a pediveliger with a developed foot, at this time, the shell length size was 320 360 $\mu\textrm{m}$.

• 한국수산과학회지
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• 제21권1호
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• pp.35-41
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• 1988

진해만내의 진동 고현 연안에서 진주 담치의 효율적인 종묘생산 기술 개발을 위하여 부유유생의 출현시각와 각 유생 단계별 생존율을 조사한 결과는 다음과 같다. 1. 진주 담치의 산란성기는 4월 중순경 이었다. 2. D형 유생으로부터 umbo형 유생까지는 11-13 일이 소요되었으며 umbo형 유생에서 성숙 유생까지는 10-13일이 소요 되었다. 그리고 D형 유생에서부터 채묘의 대상이 되는 성숙 유생까지는 23-25일이 소요되었다. 3. D형 유생에서 umbo형 유생으로 성장할 때까지의 평균 존재율은 $21.04\%$, umbo형 유생에서 성숙 유생까지는 $16.89\%$였고, D형유생의 $3.55\%$ 만이 성숙 유생으로 생존하였다. 4. 진해만산 진주 담치의 채묘적기는 5월 중순경이라고 판단된다.

• 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.