• Fisheries and Aquatic Sciences
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• 제6권2호
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• pp.51-58
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• 2003

The gonadal development and the gametogenic cycle and the fine structure of ripe germ cells of the cultured Pacific oyster, Crassostrea gigas were investigated using oysters monthly collected from the southern coast of Korea from October 2000 to September 2001. Monthly changes in the condition index were similar to that of meat weight rate and the highest value was observed in between April and May, and the lowest value in August. The external colors of the testis and the ovary were milky white and yellowish, respectively. The spawning period of the Pacific oyster was continued from May to September, with a peak in July. The gametogenic cycle could be classified into five successive stages: multiplicative stage (December to March), growing stage (March and April), mature stage (April to June), spawning stage (June to August) and resting stage (August to January). Variety of egg yolk granules, lipid granules, mitochondria, and endoplasmic reticula were observed in cytoplasm of ripe oocyte. The spermatozoon consisted of the head, middle piece and tail; including cap-shaped acrosome with domed structure, elliptical shaped nucleus, four mitochondria, two centrioles and flagellum.

• 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).

• Animal cells and systems
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• 제11권2호
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• pp.227-234
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• 2007

Spermatogenesis, the reproductive cycle, and the size at first sexual maturity in male Mactra chinensis were investigated by cytological and histological observations. The spermatozoon exhibits a primitive type morphology and is similar to those of other bivalves in that it contains a short midpiece with four mitochondria surrounding the centrioles. The morphologies of the sperm nucleus type and the acrosome shape of this species are cylindrical and modified cap-like, respectively. The spermatozoon is approximately $40-45\;{\mu}m$ in length including the sperm nucleus (about $1.46\;{\mu}m$), acrosome (about $1.20\;{\mu}m$) 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 this species lasts from June to September, and the main spawning occurs in July and August, when the seawater temperature is greater than $20^{\circ}C$. The percentage of individual male clams at first sexual maturity was 56.5% for those whose shell lengths were 35.1-40.0 mm, and 100% for over 45.1 mm. Accordingly, harvesting clams <35.1 mm in shell length could potentially cause a drastic reduction in recruitment, and a measure indicating a prohibitory fishing size should be taken for adequate fisheries management.

• 한국어류학회지
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• 제20권3호
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• pp.163-166
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• 2008

줄납자루 A. yamatsutae 정자의 미세해부학적 구조를 전자현미경으로 관찰하였다. 칼납자루 정자의 미세해부학적 구조는 경골어류 및 잉어과 어류의 일반적인 구조와 유사하였다. 즉, 둥근 두부와 긴 미부의 tangent한 연결, 비대칭적인 짧은 중편의 구조를 하고 있었다. 중편의 미토콘드리아는 핵과 유사한 크기로 하나로 융합되어 핵이 기울어진 방향에 위치해 있었다. 잉어과 중편에서 관찰되는 불규칙한 모양의 vesicle과는 달리 줄납자루에서는 vesicle이 미토콘드리아의 주위를 규칙적으로 둘러싸고 있었다. 이와 같은 융합된 미토콘드리아와 소포(vesicle)의 규칙적인 배열은 bittering에 속하는 Acheilognathus와 Rodeus에서 공통적으로 나타나는 특징이다. 두 중심립의 각도는 해부학적 단면상에서 약 $125^{\circ}C$로 나타나며 기부중심립의 위치는 핵이 기울어진 방향에 위치한 것과 핵이 기울어지지 않은 곳 2가지 type으로 나타나고 있었다.

• 한국수산과학회지
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• 제33권3호
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• pp.171-175
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• 2000

1998년 7월 섬진강 하구에서 채집한 참재첩, Corbicular leana를 대상으로 전자현미경적 연구를 수행하였다. 정원세포는 웅성생식세포 가운데서 가장 크고, 제1차 정모세와와 제2차 정모세포는 크기와 핵내 이형염색질의 응축정도로서 구분이 가능하였다. 정세포에서 정자로의 변태과정에서 핵내의 물질은 섬유상 다발을 형성한 이후 변태완료 후에는 섬유상 다발은 사라졌다. 성숙정자는 채찍모양으로 전형적인 primitive type이었으며, 첨체부는 $3\;{\mu}m$, 핵질부는 $9\;{\mu}m$ 전후 였다. 핵질부 후반부는 중심체쪽으로 융기되어 있고, 중편에는 2개의 중심체와 4개의 신장된 미토콘드리아를 가지고 있었다. 꼬리는 전형적인 9+2구조를 가졌다.

• Fisheries and Aquatic Sciences
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• 제10권3호
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• pp.143-149
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• 2007

This study describes spermatogenesis and sperm ultrastructure of the granular ark, Tegillarca granosa using light and electron microscopy. In the active spermatogenic season, the testis comprises many spermatogenic follicles that contain germ cells in different developmental stages. Primary spermatocytes in the pachytene stage are characterized by synaptonemal complexes. The early spermatids are characterized by the appearance of several Golgi bodies, increased karyoplasmic electron density, and tubular mitochondria. The mass of proacrosomal granules consists of numerous heterogeneous granules with high electron density that are about 20 nm in diameter. From the midstage of spermiogenesis, the well-developed mitochondria in the cytoplasm aggregate posterior to the nucleus and surround the proximal and distal centrioles. The proacrosomal granules condense and form a single acrosome with a thin envelope. During late spermiogenesis, the acrosome begins to elongate becoming conical. The sperm is approximately $35.0{\mu}m$ long and consists of a head, midpiece, and tail. The head comprises a round nucleus and a conical acrosome. A micro fibrous axial rod is observed between the nucleus and acrosome. The midpiece has a calyx-like structure with five mitochondria, and the tail, which has the typical "9+2" microtubular system, originates from the distal centriole.

• Applied Microscopy
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• 제40권4호
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• pp.253-259
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• 2010

바다잉어과(Osmeridae)에 속하는 빙어(Hypomesus niponesis)의 정소 내 성숙한 정자들을 전자현미경을 이용하여 조사하였다. 빙어의 정소는 한 쌍으로 부레와 창자 사이에 위치하였고 좌측 정소가 우측 정소보다 큰 것으로 나타났으며 흰색이었다. 정소 내의 성숙한 정자의 길이는 $26{\mu}m$ 정도였다. 두부는 난형으로 직경은 400 nm 정도였으며 첨체는 관찰되지 않았고, 특히 염색질의 이질적 응축이 관찰되었다. 두부의 핵이 함입되어 핵와(nuclear fossa)가 깊게 형성되었으며 핵와 내 기저부에서 편모가 직선으로 분포하였고 편모의 미세소관은 전형적인 9+2 구조를 이루고 있었다. 또한 편모의 외측에는 두개의 axonemal fin이 관찰되었으며, 중편에는 미토콘드리아가 하나만 존재하였다.

• 한국패류학회지
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• 제22권2호
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• pp.115-124
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• 2006

Gonad index, spermatogenesis and the reproductive cycle of Meretrix petechialis were investigated by cytological, histological observations. Monthly changes in the gonad index coincides the gonadal development. The morphology of the spermatozoon had a primitive type and is similar to that of other bivalves having a short mid-piece with five to six mitochondria surrounding the centrioles. The morphology of the sperm nucleus type and the acrosome shape of this species were cylindrical type and cap-like shape, respectively. The spermatozoon was approximately 40-45 ${\mu}m$ in length including the sperm nucleus length (about 1.50 ${\mu}m$), acrosome length (0.60 ${\mu}m$) and tail flagellum. The axoneme of the tail flagellum consisted of nine pairs of microtubules at the periphery and a pair at the center. The axoneme of the sperm tail showed 9 + 2 microtubular arrangement. The spawning period was from June to September and the main spawning occurred from July to August when seawater temperatures were higher than $20^{\circ}C$. The reproductive cycle of this species could be categorized into five successive stages: early active stage (February to March), late active stage (February to May), ripe stage (April to July), partially spawned stage (June to September), and spent/inactive stage (September to February).

• Restorative Dentistry and Endodontics
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• 제6권1호
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• pp.87-92
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• 1980

생쥐 치수내 조상아세포의 미세구조연구 중에 종종 보게되는 원형섬모의 미세구조와 이들의 가능한 기능을 다음과 같이 추정하였다. 1. 상아질형성물질을 분비하는 기능을 가진 조상아세포내 2가지 다른 형태의 원형섬모가 발견된다. 2. 조상아세포내 2개의 Basal Centriole을 가지고 있으면서 아마 중앙에는 쌍으로 된 microtuble이 없고 쌍으로 된 9개의 말초섬유를 가진 형태의 원형섬모는 조상아세포와 치수내 말초신경 사이에 일어나는 지각 기능에 관여 하는 것으로 추측된다. 3. 다른 한형태의 섬모, 즉 한개의 Centriole을 가지고 있으면서 쌍으로된 9개의 말초섬유를 가진 섬모는 조상아세포에서 분비된 상아질 형성물질을 움직이게 하는 이동가능에 관여하는 것으로 사료된다.

• Applied Microscopy
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• 제26권1호
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• pp.33-45
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• 1996

The spermatogenesis of Korean slug, Incilaria fruhstorferi are observed by electron microscope. The results are as follows: The spermatogenesis of Korean slug, Incilaria fruhstorferi, is processed through the five stages; Spermatogonia, primary spermatocyte, secondary spematocyte, spermatid and spermatozoon. The spermiogenesis, the differentiation of the spermatid, is also processed through the five stages. In stage 1, the numerous and round mitochomdria in the cytoplasm are moved around the nucleus of spermatid. In stage 2, the nucleus of spermatid transformed into the oval shape, and the oval nucleus is surrounded by many rough endoplasmic reticulum. In stage 3, the oval nucleus of spermatid is changed to be curved as an arrow, and then two centrioles appeared behind nucleus. The centriole is sucked into the cytoplasm. and almost all the chromatins are changed into heterochromatins. In stage 4, the nucleus of spermatid are transformed into the oval shape, when the lamella plate chromatin of spermatid form in the nucleoplasm. In stage 5, the oval nucleus is then transformed into the stream-line shape when the lamella plate chromatin of spematid gradually concentrated in the nucleus, and long axoneme ($65{\mu}m$ in length) form from the distal centriole. Two long mitochondria in the middle piece and the main piece of spermatozoon array spirally along a long axoneme, and the mitochondria matrix is gradually filled with electron-dense glycogen particles ($0.1{\mu}m$ in size). The axoneme of spermatozoon consists of typical 9+2 microtubular pattern.