• 한국동물생명공학회지
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• 제35권3호
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• pp.223-231
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• 2020

Karyotype analysis is a major work in the process of triploid abalone production for the purpose of productivity and quality improvement. However, the metaphase spreads for karyotype analysis have been prepared just from the larvae at trochophore stage, which has restricted the spectrum of sample correction inhibiting more efficient analysis. Here, we investigated the feasibility of preparing metaphase spreads from the larvae at veliger stage that is the next developmental stage of trochophore. For this, diploid and triploid larvae at trochophore and veliger stages from Pacific abalone (Haliotis discus hannai) were subjected to metaphase spread preparation and its efficiencies were measured and compared each other. As the results, although the efficiencies of metaphase spread preparation were significantly lower in the larvae at veliger stage compared to the ones at trochophore stage regardless of ploidy status, we found that the preparation of metaphase spreads, which showed the clear chromosomal images containing the normal number of chromosomes, was possible from the veliger stage larvae. On the other hands, all larvae used in this study regardless of developmental stage and ploidy did not show colchicine sensitivity. Moreover, no significant difference was observed in cell cycle distribution of the cells comprising larvae between two developmental stages regardless of ploidy status. These suggested that the details of protocol to prepare metaphase spreads from abalone larvae should be optimized depending on its developmental stages. Taken together, we demonstrated the feasibility of preparing metaphase spreads from H. discus hannai veliger stage larvae for karyotype analysis.

• 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.

• Ocean and Polar Research
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• 제37권1호
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• pp.37-47
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• 2015

The effects of low salinity (fertilization success and larval survival) on the limpet Cellana grata were studied at early stages of development using the marine bioassay technique. It was shown that, under normal conditions for development from fertilization to the post veliger stage, the salinity must be not less than 20.0~35.0 psu. However, the fertilization rate and larval survival of C. grata was obviously reduced at 5.0 psu and 10.0 psu, respectively. Mass mortality was estimated to occur at <20.0 psu (48-h $EC_{50}=19.54psu$) and the survival rate of normal veliger larvae decreased with experimental time during exposure. No observed effective concentration (NOEC) and lowest observed effect concentration (LOEC) of post veliger were estimated at 30.0 psu and 25.0 psu, respectively, during 48-h exposure. The tolerance limits of the test species to salinity revealed various concentration ranges of salinity, which may reflect the physiology and ecology of the initial development stages of C. grata. These results demonstrate that reduced salinity is detrimental to the reproductive success and larval survival of C. grata, and if salinity is lowered by natural or anthropogenic sources during spawning, this would lead to decreased reproductive success and larval settlement.

• 한국패류학회지
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• 제32권1호
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• pp.37-43
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• 2016

This study was carried out to determine the optimal water temperature for the embryonic development and laboratory culture of larvae of an intertidal mud snail, Nassarius festivus. The embryos and hatched veliger larvae of N. festivus were incubated at six different temperatures (5, 10, 15, 20, 25 and $30^{\circ}C$). Developmental time for each stage decreased as water temperature increased. The elapsed time to develop to the veliger larva at 15, 20, 25 and $30^{\circ}C$ was 559, 155, 131 and 103 hrs, respectively. At 5 and $10^{\circ}C$, embryo developed to veliger larvae but failed to hatch out of the egg capsule. In contrast, all embryos successfully hatched in the temperature range from 15 to $30^{\circ}C$. The biological minimum temperature during the embryonic development of N. festivus was estimated to be $9.5{\pm}0.4^{\circ}C$. The cumulative water temperatures for blastula, gastrula and veliger stages were calculated as $111{\pm}84$, $486{\pm}185$, $1,164{\pm}72^{\circ}C$, respectively. Temperature also affected the larval survival. Five days after hatching, more than 84% of larvae survived at all experimental temperatures. However, survival began to decrease after 6 days. It was 0% at $30^{\circ}C$. Survival of larvae incubated for 8 days was higher at 15 and $20^{\circ}C$ than other experimental temperatures. We therefore suggest that the optimal range of temperature for embryonic development and larval survival of N. festivus is $15-20^{\circ}C$.

• Environmental Engineering Research
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• 제22권1호
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• pp.108-115
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• 2017

Chlorination has been the most common antifouling method, but alternatives are under searching. In this article, we report how the hydrogen peroxide could enhance the effect of chlorination to prevent fouling by inhibiting larvae settlement and abatement of mussel colonization or by extinct of them; through marine mussel Mytilus edulis. The addition of hydrogen peroxide shows synergic effect on the veliger larvae (up to 19 folds) and effectively reduces required time of mussel mortality by 8-22%. For resolution of micro- and macro-fouling caused by the marine mussel, as well as diminishing of time and conventional chlorine dose could be important factor in favour of environment and economics.

• 한국발생생물학회지:발생과생식
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• 제18권1호
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• pp.25-31
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• 2014

This study was investigated spawning behavior, structure of egg masses and egg development in Aplysia kurodai inhabiting the coastal waters of Jeju Island, Korea. The mating and courtship behavior of A. kurodai occurred in the form of unilateral copulating with chain formation. In chain copulation, only the first animal acted as a female; the second and succeeding animals acted as males (sperm donors) to the animals in front and as females to the animals behind. The fertilized eggs were packaged in capsules that are embedded in jelly to form a cylindrical string called an egg masses. The number of capsule per cm of the egg masses was 55 to 60 capsules and each capsule within the egg masses held 15 to 25 eggs. After spawning, the egg masses were bright yellow or orange in color. This egg masses color not changed until embryos developed into trochophore stage. Thereafter, as embryo developed from trochophore stage to veliger stage the egg masses color became brownish. The fertilized eggs were spherical, with a diameter of approximately $80{\pm}1{\mu}m$ at spawning. At 5 to 6 days after spawning, the embryo developed into trochophore stage and began to rotate within the egg capsule. In the trochophore stage, the precursor of the velum, called the prototroch or prevelum, developed. At 10 days after spawning, the prevelum is transformed into the velum, and the trochophore developed into veliger stage. Between 10 to 15 days after spawning, the veligers broke out of the egg capsule, and hatched as free-swimming larvae.

• 한국발생생물학회지:발생과생식
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• 제15권4호
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• pp.301-308
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• 2011

결빙억제제(CPA)의 종류, 농도 및 침지시간이 참전복 Haliotis discus hannai 발생배의 생존활성에 미치는 영향을 조사하였다. 4세포, 담륜자 및 피면자를 dimethyl sulfoxide, ethylene glycol, propylene glycol 농도별로 10분, 20분 및 30분간 침지하였다. CPA 침지 후 각 발생배의 발생진행률은 각 CPA 농도가 낮을수록, CPA 침지시간이 짧을수록 높았다. 또한, 피면자에서 비틀림전까지의 발생진행률은 4세포에서 담륜자까지의 것보다 높았다. CPA 침지 후 발생진행률 및 유생활성지수는 ethylene glycol에서 가장 높았다. 참전복 발생배의 냉동보존 효과를 높일 수 있는 CPA 및 농도는 ethylene glycol 2.0 M, 평형시간은 30분인 것으로 추정된다.

• 한국수산과학회지
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• 제34권2호
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• pp.131-136
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• 2001

양산시 내원사 계곡에 서식하는 다슬기 (Semisulcospira libertina libertina)를 대상으로 상대성장과 보육낭내 유생조성을 조사하였다. 조사한 다슬기의 총 개체수는 1,200마리였으며, 각고(SH), 각경 (SD), 전중 (TW), 육중 (MW) 및 각중 (SW) (평균$\pm$표준편차)은 각각 $15.96\pm3.41\;mm$, $7.82\pm1.38mm$, $0.55\pm0.31\;g$, $0.24\pm0.15g$, $0.39\pm0.23g$이었다. 각각의 상대성장식은 SD=0.3583 SH+2.1648 $(R^2=0.8391),\;TW=0.0005SH^{2.4853}\;(R^2=0.8391)$, $MW: 0.0005SH^{2.849}\;(R^2= 0.8391)\;SW=0,0004SH^{2.3798}\;(R^2=0.7057)$였다. 다슬기는 연중 보육낭내 발생중인 유생을 갖고 있었으며, 유생수는 봄$\cdot$여름에 감소하고 가을에 증가하는 경향을 보였다. 다슬기 암컷 1개체당 보육낭내의 평균 유생수는 11월에 396$\pm86$마리로 가장 많았으나, 7월에는 $91\pm86$33마리로 가장 적은 수를 나타냈다. 보육낭내 유생의 발달단계별 조성에 있어서 trochophore는 5월에 $66.7\%$, pre-veliger는 11월에 $70.7\%$, veliger는 2월에 $60.9\%$, juvenile은 1월에 $13.9\%$로 가장 높은 값을 보였다. 출산 전 단계인 juvenile의 빈도는 $3\~5$월, $8\~11$월에 감소하는 경향을 나타냈다. 이상의 조사결과에 따라, 다슬기의 출산성기는 $3\~5$월, $8\~10$월의 연 2회인 것으로 추정되었다.

• 한국패류학회지
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• 제2권1호
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• pp.26-29
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• 1986

Corbicula fluminea, one of the 2 species in the family Corbiculidae living in the Lake Uiam, was used as an experimental material and the embryonic development and the structure of glochidia of this species were investigated. This freshwater mussels was oviparous, but some ovoviviparous: incubated their youngs in the inner-demibranchs or outer-demibranchs, however, chiefly used the inner-demibranchs as brood-pouch. The average time required from a fertilized egg to two-cell stage, veliger stage, and glochidium was 76 minutes, 3 hours, and 17 hours, respectively, The mean size of glochidium was $168{\mu}m$ in shell height, $195{\mu}m$ in shell lengh, $114{\mu}m$ in hinge legth and the form of glochidium was D-type and had no hooks or hooklets for attaching to fish like Unioidae.

• 한국수산과학회지
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• 제7권1호
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• pp.1-6
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• 1974

1973년 6월 20일부터 동년 8월 25일까지 사이에 Meretrix lusoria의 성숙난에 $NH_4OH$ 해수용액을 규정농도별로 처리한 후의 인공수정율, 초기발생과정 및 유생의 변태과정을 조사하였다. 1. M. lusoria의 $NH_4OH$ 해수용액 처리에 의한 규정농도별 수정률은 1/1000 N의 $NH_4OH$ 해수용액 처리로 가장 높은 인공수정률을 얻었고, 이렇게 처리된 후 인공수정된 난의 발생과정도 정상적임을 확인하였다. 2. M. lusoria의 초기발생과정에서는 수정후 1시간 35분이 지나면 2할기, 4시간 40분에 포배기, 6시간 15분에 Trochophore기에 달함을 볼 수 있었다. 3. M. lusoria의 유생을 사육한 결과, 수정후 10이 지나면 원각의 평균각장이 $112\mu$인 초기 D형에, 7일이 지나면 평균 각장이 $172\mu$인 각정기에, 20일이 지나면 평균 각장이 $232\mu$인 초기저서기에 달함을 볼 수 있었다. 4. M. luroria의 유생을 실험실내 수조 속에서 사육하며 각장 $272\mu$인 치패을 얻을 수 있었다. 5. M. luroria의 초기 D형기로 부터 변태기까지의 각장(L)과 각고(H)와의 관계는 H=1.02325L-24.46425(상관계수 r=0.99050)의 식으로 표시되었다.