• Animal cells and systems
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• 제3권4호
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• pp.375-383
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• 1999

Gonadal development, gametogenesis, reproductive cycle, and first sexual maturity of Reishia clavigera were investigated monthly from July 1998 to June 1999 through cytological and histological observations. R. clavigera had separate sexes, and was an internal fertilizer. The ma1e penis was located near the two tentacles. The ovary and testis were composed of a great number of oogenic lobules and spermatogenic tubules, respectively. The size of ripe oocyte ranged from 130 to 140 ${\mu}$m in diameter. The peripheral cytoplasm of the germinal vesicle of the ripe oocyte in many cases were surrounded by smaller yolk granules, while the eccentric cytoplasm was occupied with larger ones. The reproductive cycle of R. clavigera could be classified into five successive stages: early active, late active, ripe, spawning, and recovery. Spawning of females occurred from early July to August when the seawater reached above 24.8$^{\circ}C$. Spawning of males occurred from early June to August in the water above 22.8$^{\circ}C$. Minimum size for sexual maturity of both sexes was above 10.0 mm in shell height. Each egg capsule was a cylinder or spindle in shape, 4-6 mm in length and 1-2 mm in width. Colors of newly spawned egg capsules showed yellowish white or pale yellow, while those with veliger larvae showed pale black, and released larvae or dead egg capsules showed black violet. The fecundity in an egg capsule ranged from 70 to 91 eggs (mean＝80.28 eggs).

• 한국발생생물학회지:발생과생식
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• 제18권4호
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• pp.259-266
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• 2014

The egg development and early life history of Korean spotted sleeper, Odontobutis interrupta which is Korean endemic species from Sora-choen was investigated. The Korean spotted sleeper were caught at Sora-myeon, Yeosu-si, Jeollanamdo, from Korea at May in 2014. The fertilized eggs were $4.23{\pm}0.05mm$ in long diameter and had oil globules. Hatching time of the embryo began about 442 hr 14 min after fertilization under water temperature of $19.5^{\circ}C$. The newly hatched larvae were $4.27{\pm}0.35mm$ in total length and their anus were not yet opened. 3 days after hatching postlarvae was measured $6.20{\pm}0.11mm$ in total length. 10 days after hatching postlarvae was measured $6.69{\pm}0.14mm$ in total length.

• 한국어류학회지
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• 제18권3호
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• pp.266-272
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• 2006

한국 고유종인 한강납줄개, Rhodeus pseudosericeus의 난발생과 초기 생활사에 대해 관찰하였다. 담황색 성숙란의 난경은 $2.9{\sim}3.1{\times}1.6{\sim}1.9 mm(n=30)$이었다. 수정란은 수온 $17.0{\pm}0.5^{\circ}C$에서 수정 후 70시간 만에 부화하였다. 부화 자어의 크기는 3.2~3.4 mm (평균 3.3 mm)이고 부화 후 25일 경에 난황이 흡수되었으며 소화기관이 완성되어 먹이를 먹기 시작하였다. 전기자어 시기에 출현하는 익상돌기는 납줄개속의 특징을 잘 나타내 주고 있다.

• 한국수산과학회지
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• 제8권4호
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• pp.225-233
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• 1975

1968년 6월,1969년 7월 및 1971년 7월에 해운대 동백섬 연안에서 채집된 953개체의 점망둑 자치어를 재료로 하여 초기생활사에 따른 형태변화 과정중 기조수의 변화, 색소포의 발달과정 및 배지느러미의 형성과정을 관찰하였다. 본 종은 제1등지내러미의 기조원기는 8.0 mm 전후에서 생겨나며 9.2mm 전후에서 완성하며 모든 지느러미의 연조는 초기치어기인 17.0mm 전후에서 완성된다고 생각된다. 색소포의 발달은 3단계로 구분할 수 있는데 후기자어기$(6.3\~14.2mm)$ 있어서 몸의 배면과 미부 복측면 및 꼬리지느러미 기저에 분포하고 있는 경우와, 후기 자어말기$(17.0\~2.44mm)$에 미부의 체측정중선에 일단의 색소총이 생기고 이것이 점점 전방으로 확대분포하는 시간 및 초기치어기$(27.2\~34.8mm)$에 몸 전체에 걸쳐 운형 및 H자상으로 분포되어 종의 특징을 나타내는 시기로 구분된다. 배지느러미의 형성과정은 후기자어기인 전장 7.4mm일 때 기조의 원기가 나타나서 17.0mm 전후에 기조가 완성되며 전장 30.0mm 전후에서 흡반이 완성된다.

• 한국어병학회지
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• 제20권3호
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• pp.257-267
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• 2007

The hypo-salinity effects on fertilized eggs, embryos and larvae were investigated in olive flounder (Paralichthys olivaceus) obtained from hatcheries in Cheju-Island, Yeosu and Chungnam. Those were treated to eight concentration; 0, 3.4, 6.7, 10.1, 13.4, 20.2, 27.4 and 33.6 ‰. It was not discrepancy in the survival rate and hatching success rate of fertilized embryos obtained from different regions. Also, in the larvae, the regional difference was not appeared. The survival rate and hatching ability of embryos significantly diminished in the lower groups than 13.4 ‰ compared to 33.6 ‰. After fertilization, namely embryos are tolerant of a wide range of salinity (13.4 - 33.6 ‰). Reduced salinity induced an increase of the malformed embryo and larvae including various deformities; irregular embryos membrane (or yolk sac depression), fin erosion and swim bladder inflation in the flounder embryo. The hatching success of embryos was significantly reduced in lower salinity than 13.4 ‰. Notably, the reduction of larval survival rate significantly was observed in ≤10.1 ‰ treated groups with the same manner of survival rates of the embryos. Additionally, olive flounder was found to be adequate model for measuring external impulses because there are no the regional differences.

• 한국수산과학회지
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• 제43권5호
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• pp.489-494
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• 2010

The nutritional demand of oyster larva (Crassostrea gigas) were investigated to determine the optimal culture conditions and improve micro-algae utilization. Changes in nutrients and shell growth were examined in fed and 96-h (48 h in late umbone stage) oysters at four larval stages. Shell growth increased significantly in D shape larvae, regardless of feeding variations. No growth was observed in starved larvae, except in shell length of umbone (to 11.9 ${\mu}m$). Fed larvae showed significant growth in all development stages (P < 0.05). During starvation, lipids were most significantly decreased in all larval stages (by 76.8%, 68.3%, 76.3%, and 40.3%, respectively), followed by protein (41.1%, 31.1%, 33.1%, 16.7%) and nitrogen-free extracts (40.8%, 24.3%, 36.9%, 20.1%), Gross energy (kcal/g) consumption in each larval stage was 49.6%, 35.1%, 39.1%, and 20.4%, respectively. Our results indicate that lipids are the most important energy source during the early larval development stages of C. gigas.

• Animal cells and systems
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• 제12권4호
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• pp.279-286
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• 2008

Development and distribution of larval Dungeness crab, Cancer magister Dana, 1852 were investigated in southeastern Alaska from late May to mid-September in 2004. Larvae were collected during daylight hours at three inner and two outer Glacier Bay stations at the two different depths in the water column, above and below the thermocline. Larval density decreased dramatically for three larval stages, zoeae I(ZI), zoeae IV, and zoeae V(ZV), but relatively little for zoeae II and zoeae III. ZI predominated at all stations in late May and were collected until late July. Larval stages progressed seasonally from ZI to ZV and density decreased from ZI through ZV. The densities of each zoeal stage at the inner and outer bay stations and at the shallow and deep depths were similar. The density of each larval stage above(shallow) and below(deep) the thermocline and between inner and outer bay stations were not significantly different. The occurrence of larval Dungeness crab is dramatically later than in other parts of the species range, in that larvae appear in abundance beginning in late May. The pattern of spatial distribution of larval stages for the inland waters of Alaska was also markedly different than the patterns reported for Dungeness crab larvae from other parts of the species range, in that the early and intermediate stages occurred within inland waters; from British Columbia to California these larval stages increase in abundance with distance offshore.

• BMB Reports
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• 제41권8호
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• pp.587-592
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• 2008

Cotesia vestalis is an endoparasitoid of Plutella xylostella larvae and injects a polydnavirus (CvBV) into its host during oviposition. In this report we characterize the gene, CvBV3307, and its products. CvBV3307 is located on segment S33 of the CvBV genome, is 517 bp, and encodes a putative protein of 122 amino acids, including a serine-rich region. The expression pattern of CvBV3307 in parasitized larvae and the subcellular localization of CvBV3307 only in granulocytes indicated that it might be involved in early protection of parasitoid eggs from host cellular encapsulation and in manipulating the hormone titer and developmental rhythm of host larvae. Western blot analysis showed that the size of the immunoreactive protein (about 55 kDa) in parasitized hosts at 48 hours post parasitization (h p.p.) is much larger than the predicted molecular weight of 13.6 kDa, which suggests that CvBV3307 undergoes extensive post-translational modification in hosts.

• Fisheries and Aquatic Sciences
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• 제16권4호
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• pp.253-260
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• 2013

We investigated the toxicological effects of Aroclor 1254 on the fertilized eggs, embryos and larvae of the olive flounder Paralichthys olivaceus. The survival rate and hatching success of the embryos decreased significantly in treated groups in an Aroclor 1254-dose-dependent manner. Significant differences were found at ${\geq}5{\mu}g/L$ Aroclor 1254 compared to the control group. Hatching success occurred at ${{\leq}}10{\mu}g/L$ Aroclor 1254, which was not significantly different to the control. Embryo malformation increased significantly at ${\geq}1{\mu}g/L$, and included yolk-sac and tail-flexure abnormalities. There was a significant decrease in the survival rate of the larvae at ${\geq}5{\mu}g/L$, which was accompanied by the malformations described above. Notably, concentrations as low as $1{\mu}g/L$ caused a significant increase in abnormalities in the larvae, including incidences of multi-focal hemorrhages, pericardial and yolk-sac edema, inhibition of swim bladder inflation and severe developmental delay. The responses to Aroclor 1254-induced toxicity were generally similar among fertilized eggs, embryos and larvae from three separate flounder hatcheries: Cheju Island, Yeosu and Chungnam, South Korea. These results indicate the high acute toxicity of Arolcor 1254 concentrations of which as low as $1{\mu}g/L$ in olive flounder larvae can affect unhatched embryos. To conclude, the average $LC_{50}$ values for Aroclor 1254 in the embryos and larvae were 50.92 and $3.08{\mu}g/L$, respectively. Additionally, the average $EC_{50}$ values, based on the rate of damage were 14.72 and 5.6$1{\mu}g/L$, respectively.

• 한국패류학회지
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• 제29권2호
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• pp.91-96
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• 2013

북방전복 초기 유생의 사육에 적합한 부착 규조류를 파악하기 위하여 C. californica, Rhaphoneis sp. C. schroederi를 대상으로 veliger 유생의 부착률, 변태율, 생존율 및 성장을 조사하였다. 각 규조류의 단독 먹이 실험구, 3종의 혼합 먹이 실험구 및 먹이를 공급하지 않은 대조구로 구분하여 사육하였다. 유생의 부착률은 C. californica와 Rhaphoneis sp.에서 48시간째에 80-82%로 가장 높았고, C. schroederi의 최고 부착률은 96시간째에 67%로 상대적으로 늦고 낮은 경향을 보였다. 변태율도 C. schroederi는 6일째 37%로 C. californica와 Rhaphoneis sp.의 45-49%에 비하여 낮고 느린 결과를 보였다. 혼합 먹이 실험구는 단독 먹이 실험구에 비하여 낮은 부착률과 변태율을 보였다. 변태 후 10일째 C. californica와 Rhaphoneis sp.는 각각 69%와 61%의 높은 유생 생존율을 보였고, 일간 각장 성장은 각각 33.7 ${\mu}m$과 32.5 ${\mu}m$로 C. schroederi의 29.0 ${\mu}m$, 혼합 먹이 실험구의 21.8 ${\mu}m$에 비하여 유의하게 높았다. 따라서 북방전복 초기 유생 사육을 위한 최적 규조류는 C. californica, Rhaphoneis sp., C. schroederi의 순으로, 이들 규조를 단독으로 공급하는 것이 혼합하여 공급하는 것보다 효과적일 것으로 판단된다. 그러나 본 실험은 북방전복 초기 유생단계의 결과이므로 차후 치패를 대상으로 한 장기간의 먹이효율 조사가 필요하다.