• 한국발생생물학회지:발생과생식
• /
• 제17권4호
• /
• pp.369-377
• /
• 2013

The fertilized eggs of E. septemfasciatus are spherical and transparent with buoyancy at 790 to $890{\mu}m$ (average $821.8{\pm}2.0{\mu}m$) in diameter with 170 to $230{\mu}m$ oil globules (average $192.9{\pm}0.93{\mu}m$). Hatching began approximately 46 and 35 hours after fertilization at $22.0^{\circ}C$ and $25.0^{\circ}C$ water temperature, respectively. The average total length of newly hatched larvae was $1.75{\pm}0.03mm$. Most of the yolk and oil globules were absorbed within 3 to 4 days after hatching. The larvae reached 2.48 to 2.72 mm in total length, and their mouths and anuses opened at 3 to 4 days after hatching. In this time, the mouth diameters of the larvae were 0.209 to 0.238 mm. The larvae reached 3.24 to 4.15 mm in total length at 11 to 17 days after hatching, and began to metamorphose at the time the second dorsal and pelvic spines appeared and elongated. The abdominal cavity was densely lined with melanophores. The larvae reached 5.12 mm in total length at 24 days after hatching.

• 한국발생생물학회지:발생과생식
• /
• 제8권1호
• /
• pp.11-17
• /
• 2004

북대서양에서 상업 적으로 중요한 해산어류인 Haddock Melanogrammus aeglefinus의 자치 어 발생과정과 성장을 조사하였다. 자치어는 부화 후 67일까지 사육실 조건에서 사육되었고 주기 적으로 표본한 재료를 실체 현미경으로 관찰하였다. 발생단계별 크기 변화는 부화 후부터 지속적인 성장을 보여 Y=4.07 $e^{0.037}$( $R^{2}$=0.9978)의 성장식을 나타내었다. 부화 직후의 자어는 전장 4.9 m로 장방형의 난황을 가지고 있었다. 초기 먹이섭취는 부화 후 7일에 시작되었으나 부화 후 16일 째 전장 6.8 m때에 난황이 완전히 흡수되어 후기 자어 단계가 되었다. 부화 후 16~52일의 기간에 부속기관의 발달이 활발히 진행되었으며, 전장 41.3 mm인 부화 후 61일에 턱수염은 완전히 발달되지는 않았지만 치아, 측선, 체측의 검은 반점 등은 성어와 같은 모습의 치어 단계에 도달하여 본 종은 이 시기 이후로 먹이와 생태적 행동변화가 일어나는 것으로 추정된다.다.

• 한국양식학회지
• /
• 제9권1호
• /
• pp.11-18
• /
• 1996

본 연구는 수정난에서 부터 부화후 60일 까지 황복의 배발생 및 자치어의 발달에 관한 형태적 특징을 조사하였다. 배발생 단계는 융합기, 난할기, 포배기, 낭배기, 체절형성기, 인두형성기 및 부화기 등 7가지로 구분하였다. 황복의 난은 분리부착 침성난으로 구형이며, 난황은 작고 많은 유구를 갖고 있다. 수정후 약 170시간 경에 난황 주위에 흑색소포가 출현되기 시작했다. 수온 $17.0{\pm}1.0^{\circ}C$에서 수정후 280시간에 부화되며, 부화된 자어는 큰 난황을 달고 있으며, 그 크기는 $3.00\~3.54\;mm$이고 $25\~26$개의 체절이 형성되었다. 부화후 7일에는 난황과 유구가 완전히 흡수되고 자어기에 도달했다. 부화후 60일에 자치어의 전장은 $23.54\~30.12\;mm$로 성장되며, 모든 지느러미가 형성되었다.

• 한국수산과학회지
• /
• 제51권2호
• /
• pp.170-177
• /
• 2018

Samples were obtained from broodstork in May, 1998, while naturally fertilized embryos were maintained and the process of skeletal development was observed from larvae and juveniles. Prelarvae immediately after hatching showed an average total length of $5.38{\pm}0.41mm$ (n=10), premaxillary and dentary were ossified, parasphenoid was ossified in the cranium, and centrum and caudal bone did not ossify. Prelarvae showed ossification with maxillary, articular and epihyal and branchiostegal rays of hyoid arch were ossified at 5 days after hatching with an average total length of $6.40{\pm}0.39mm$ (n=10). The vertebrae began to ossify in the direction of the tail, and neural spine began to ossify above the ossified vertebra. Postlarvae showed ossification of lateral ethmoid, parietal, and caudal skeleton in the cranium when the average total length was $7.30{\pm}0.12mm$ (n=10) in 8 days after hatching. At 22 days after hatching, postlarvae ossified maxillary in the cranium, and ossified endopterygoid and ectopterygoid, etc. in the palate, when the average length of $11.1{\pm}1.27mm$ (n=10). At 32 days after hatching, with the average length was $12.8{\pm}1.97mm$ (n=10), caudal skeleton had one additional epural bone ossification, resulting in ossification of a total of 3 epural bone to complete ossification of all spicules.

• 한국가축번식학회지
• /
• 제21권3호
• /
• pp.311-319
• /
• 1997

This study was carried out to investigate the ultrastructural changes of spermatozoa obtained from 20 of 3-year-old male chum salmon(Oncorhynchus keta) collected and analysed in middle October in 1995. The ultrastructural changes of gonad of fingerlings were examined to describe the sex differentiation of this species. The results obtained in this study were as follows : In spermatozoa, the nucleus is dense and homogeneous. Two spheroidal mitochondria(about 350nm long) are situated in parallel between the nucleus and the axoneme. Spermatozoa mitochondria are assembled into an organized sheath surrounding the outer dense fibres and axoneme of the flagellar midpiece. The sheath flagellum is situated beneath the base of the sperm head. The primordial germ cells of 6.8~7.2${\mu}{\textrm}{m}$ in size, which were buried under fibrous mesenchymal tissue between gut duct and notochord of larva with a total length of 2.4cm at 50 days after hatching. In juvenile of 10.5cm in total length at 70 days after hatching, the gonad was occupied by bundles of oogonia. The dense drumstick bodies(large arrows) are observed in the nuclei of the primordial gonad and surrounding tissue cells of fingerling at 70 days after hatching. The oval Barr bodies(asterisk) are observed in the nuclei of the primordial germ cells under the mitosis(2n). Note the large mitochondria, ribosomes and rough endoplasmic reticulum in the cytoplasm. Accordingly, the fingerlings at 70 days after hatching are identified as the female(xx). In result, the gonadal sex differentiation begins from the 70 days after hatching in chum salmon.

• 환경생물
• /
• 제24권1호
• /
• pp.53-59
• /
• 2006

본 연구는 민어의 자원조성을 위한 양식생물학적 기초자료를 얻고자 산란 특성과 부화에 미치는 염분의 영향을 조사하였다. 실험에 사용된 어미는 5년동안 자연산 암컷 39마리, 수컷 24마리로서, 암컷의 크기는 평균 전장 $72.3\sim89.6\;cm$, 평균 체중의 경우 $3,736\sim8,818\;g$이었으며, 수컷의 크기는 평균 전장 $47.1\sim81.2\;cm$, 평균 체중은 $716.6\sim6,853\;g$이었다. 안정적인 채란을 위한 민어친어의 적정크기는 전장 $97.9\sim110.2\;cm$, 체중 $9,657\sim13,200\;g$였다. 유구는 $1\sim5$ 개가 존재하며, 유구수가 1개일때 가장 높은 부화율(96.7%)을 나타내었다. 염분농도별 부화율은 30.0 ppt일때 87.0%로 가장 높았으며, 부화시간의 경우 28.0 ppt일때 17시간 24분으로 가장 짧았다.

• 한국수정란이식학회지
• /
• 제13권1호
• /
• pp.1-9
• /
• 1998

In order to improve the cryopreservation by vitrification or slow freezing of nuclear transplant rabbit embryos, the effects of factors affecting embryo cryopreservation such as cryoprotectants, equilibration, cooling rate and post-thaw dilution on post-thaw survial and development were determined using intact embryos of morular stage. And the post-thaw development of nuclear transplanted embryos cryopreserved under the optimal conditions examined was compared between vitrification and slow freezing. The cryoprotectant solution used was ethyleneglycol-ficoll-sucrose (EFS) or ethyleneglycol-poly-vinylpyrrolidone-galactose- I (EPG- I ) for vitrification, and EPG- II for slow freezing. To examine the viability of frozen-thawed embryos, the nuclear transplanted embryos were co-cultured in TCM-199 plus 10% FBS with bovine oviduct epithelial cells(BOEC) for 24 hrs and the intact morulae were co-cultured with BOEC for 5 days and 3 days to hatching blastocyst stage in 39 ˚C 5% $CO_2$ incubator. The results obtained were as follows: Following vitrification with EFS, the post-thaw development of rabbit morulae to hatching blastocyst was significantly(P<0.05) higher in compacted stage(82.4%) than in early morular stage(60.0%). The post-thaw development of compacted morulae to hatching blastocyst was similarly high in vitrification with EFS(82.4%), EPG- I (85.0%) and in slow freezing with EPG- II (83.3%). Following vitrification with EPG- I, the post-thaw development of intact rabbit morulae to hatching blastocyst was similar as 78.0% and 85.0% in 1-step and 2-step post-thaw dilution, respectively. The post-thaw development of nuclear transplanted rabbit embryos of compacted morulae stage to hatching blastocyst was similarly 43.6% and 40.0% in vitrification with EPG- Iand slow freezing with EPG- II, respectively. These results indicated that the rabbit nuclear transplant and intact embryos of morulae stage could be well cryopreserved with either vitrification or slow freezing procedure.

• 한국수산과학회지
• /
• 제48권3호
• /
• pp.362-367
• /
• 2015

We followed the development of Pacific herring Clupea pallasii larvae after natural hatching in Korean coastal waters off Dadaepo, where the water temperature was $9^{\circ}C$. Twenty days after hatching, the larvae had (i) reached a total length (TL) of 10.8-12.2 mm, (ii) developed 9-11 dorsal fin rays, and (iii) branched melanophores along the dorsal line of the gut in the anterior half of the body and along the posterior half of the dorsal and ventral line. Thirty days after hatching, the larvae had reached 12.2-13.5 mm TL, and the number of dorsal fin rays had increased to 13-14. Thirty-five days days after hatching, the larvae had reached 14.0-14.7 mm TL, and the posterior ends of their notochords had begun to flex upward. Forty-five days days after hatching, the larvae had (i) reached 15.6-15.9 mm TL, (ii) a complete set of dorsal fin rays (15-16), (iii) 12-13 anal fin rays, and (iv) branched melanophores along the dorsal part of the lateral surfaces of the head behind the caudal terminus. Preflexion, flexion and postflexion stage larvae had TL values of 13.5 mm, 14.0-15.3 mm, and 15.6-15.9 mm, respectively.

• 한국응용곤충학회지
• /
• 제29권1호
• /
• pp.20-24
• /
• 1990

사과나무 응애류의 월동밀도와 사과응애난의 부화시기와 부화율 그리고 응애류의 발생소장을 '87년부터 '89년사이에 경북지방 사과원에서 수행한 결과는 다음과 같다. 응애류의 월동밀도는 사과응애난은 군위, 안동, 칠곡지방에서는 모두 높았으나 남쪽지역인 경주지방에서는 아주 낮았다. 점박이응애의 월동성충은 조사지역 공히 밀도가 높았으며 주로 사과나무 내부조피에서 월동하고 있었다. 사과응애의 지역별 부화시기 및 부화율을 보면 부화개시일은 4월 14얼이었으며 부화종료일은 5월 3일이었다. 부화율은 지역간 차이가 없었으며 평균 89.3%였다. 응애류의 발생소장 조사결과 사과응애(Panonychus ulmi) 사과잎이 전개되면서 부화하여 5월 상순부터 7월 중순까지 우점하였으며, 점박이응애(Tetranychus urtcae)는 6월 중순부터 밀도가 급격히 증가하여 7월 이후에는 점박이응애가 우점종 이었다.

• Animal cells and systems
• /
• 제12권4호
• /
• pp.297-304
• /
• 2008

Morphology and distribution of the minute tubercles projected on the skin surface of larvae with its development were observed in the Korean bitterling, Acheilognathus somjinensis. The minute tubercles appeared to be two distinct morphologies, hemispheric or scaly and vestigial structures. Just after hatching, the epidermis of the larvae consists of a thin single cell layer having smaller basophilic flat or round-flattened basal cells. As the larvae grow, the epidermis contains more small flat cells and large epidermal cells which are round and hemispheric, or scaleshaped, called minute tubercles. They are distributed over the anterior part and most part of yolk sac, posterior region of yolk sac and the body region. Vestigial epidermal cells, another minute tubercle, occur only in the caudal fin-fold region, which they are shrunken and flattened, causing the cell boundary to be unclear. They increase in number and height from just to 5 days after hatching, but they become reduced as the larvae develop gradually. The required time for those disappearance was different each by regional body: at day 20 after hatching in the anteriormost part of yolk sac, and day 11 after hatching in the posterior part of yolk sac and the body, and day 21 after hatching in two regions such most part of the yolk sac and the caudal finfold regions.