• 한국발생생물학회지:발생과생식
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• 제20권3호
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• pp.247-254
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• 2016

Cytological changes of the epithelial cells according to the developmenatal phases of the seminal vesicle related to the spermatogenic stages in the testicular lobules during spermagenesis in male Neptunea (Barbitonia) cumingii (Gastropoda: Buccinidae) were investigated monthly by electron microscopical and histological observations. N. (B) cumingii is dioecious, and an internal fertilization species. The male genital organ is located near the tentacles. The spermatozoon is approximatley $50{\mu}m$ in length. The axoneme of the tail flagellum consists of nine pairs of microtubles at the periphery and one pair at the center. The process of germ cell development during spermatogenesis can be divided into five succesive stages: (1) spermatogonia, (2) primary spermatocytes, (3) secondary spermatocytes, (4) spermatids, and (5) spermatozoa. A considerable amount of spermatozoa make their appearance in the testicular lobules (or acini) and some of them are tranported from the testis towards the seminal vesicles until late July. In this study, the developmental phases of the epithelial cells of the seminal vesicles of N. (B.) cumingii could be classified into four phases: (1) S-I phase (resting), (2) S-IIphase (early accumulating), (3) S-III phase (accumulating), and (4) S-IV phase (spent). However, in case of N. (B.) arthritica cumingii, the developmental phases of the seminal vesicle were devided into three phases: (1) resting, (2) accumulating and (3) spent. Granular bodies in the inner layer of the seminal vesicles are involved in resorption of digestion of residual spermatozoa.

• 한국발생생물학회지:발생과생식
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• 제17권2호
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• pp.121-132
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• 2013

Ultrastructural characteristics of the germ cells and accessory cells in testis during spermatogenesis and taxonomic values of mature sperm morphology of Ruditapes philippinarum were investigated by the transmission electron microscope and scanning electron microscope observations. The testis is the diffuse organ that consists of branching acini containing developing germ cells and accessory cells associated with spermatogenesis. The morphology of the spermatozoon is of the primitive type and is somewhat different to those of other bivalves. The morphologies of the sperm nucleus type and the acrosome shape of this species have a cylinderical type and a modified cone shape, respectively. As some ultrastructural characteristics of the acrosomal vesicle, the peripheral parts of two basal rings show electron opaque part, while the apex part of the acrosome shows electron lucent part. These characteristics of sperm belong to the family Veneridae in the subclass Heterodonta, unlike a characteristic of the subclass Pteriomorphia showing all part of the acrosome being composed of electron opaque part. In particular, a cylinder-like nucleus of the sperm is curved. The spermatozoon is approximately $48-51{\mu}m$ in length, including a long acrosome (about $2.4{\mu}m$ in length), a curved sperm nucleus (about $3.40{\mu}m$ in length), and a tail flagellum. The axoneme of the sperm tail shows a 9+2 structure.

• Fisheries and Aquatic Sciences
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• 제8권1호
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• pp.17-26
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• 2005

The ultrastructure of germ cells during spermatogenesis and the structural changes in the epithelial cells of the seminal vesicle with testicular development in male Neptunea (Barbitonia) arthritica cumingii were investigated monthly based on electron microscopic and histologic observations. N. arthritica cumingii (Gastropod: Buccinidae) undergoes internal fertilization and possesses a modified type of spermatozoon, which is approximately 20$\mu$m long. The axoneme of the tail flagellum consists of nine peripheral pairs of microtubules and one central pair. Many spermatozoa occur in the acini of the testis in the ripe stage and are transported to the seminal vesicles in the accumulating phase. In males, the monthly gonadosomatic index began to increase in September and reached a maximum in February. Subsequently, it decreased rapidly after April. The testis of this species can be classified into four developmental stages: the active (August to September), ripe (October to July), copulation (April to July), and recovery (July to August) stages. Structural changes in the epithelial cells of the seminal vesicles of this species could be classified into three phases: (1) S-I (resting), (2) S-II (accumulating), and (3) S-III (spent) phases. The morphology and structure of the epithelial cells of the seminal vesicle differed in each phase; the cells were cuboidal, squamous, or columnar in the resting, accumulating, or spent phases, respectively.

• 한국어류학회지
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• 제8권1호
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• pp.1-8
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• 1996

저서성 어류인 Cobitis striata의 정소는 좌우 한쌍의 가늘고 긴 촛대모양으로서 체벽에 매달려 있다. 또한 미성숙한 정소는 규칙적인 배열을 하는 많은 정소엽으로 구성되어 있으나 성숙된 정소에서 는 복잡한 망상구조(network)를 보였다. C. striata의 정자는 첨체가 없어 수중으로 배정되는 무첨체 수중형(anacrosomal aquasperm)이며, 구형의 핵을 갖는다. 중편은 길이가 약 $0.8{\mu}m$으로서 아주 짧았으며, ring모양의 미토콘드리아가 5~8개 존재하였다. 편모는 하나로서 전형적인 9+2구조를 보이며 돌기물(fin)이 없는 특징을 보였다.

• 한국수산과학회지
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• 제40권3호
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• pp.147-152
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• 2007

Spermiogenesis and mature spermatozoa of the Korean false minnow Pseudogobio esocinus (Cyprinidae) are described by means of scanning and transmission electron microscopy. Spermiogenesis is characterized by lateral development of the flagellum, absence of nuclear rotation, and eccentric nuclear fossa formation. The spermatozoa have a spherical head containing a nucleus with highly condensed chromatin and no acrosome. The nuclear fossa contains the proximal centriole and anterior part of the distal centriole. The midpiece is type A II and contains semi-fused mitochondria around the axoneme. However, the symmetrical distribution of 4 or more the mitochondria does not follow a general pattern of the cyprinid spermatozoa. Cytoplasmic vesicles in the midpiece are common in Cypriniformes and some of Siluriformes and Characiformes spermatozoa.

• 한국수산과학회지
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• 제28권6호
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• pp.736-752
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• 1995

Fine structural changes of germ cell during the gametogenesis of Korean rockfish, Sebastes schlegeli sampled in west coast of Korea were investigated from September 1993 to August 1994. In a layer of microvilli of oocyte with active yolk duplication, many pinocytotic vesicles containing protein granules regarded as yolk precursors were observed. The multivesicular bodies were formed by gathered mitochondria. They are participated in formation of the primary yolk globules homogeneously filled with high dense particles and enclosed within a limiting membrane. The precursors of yolk globule appeared to be formed by modification of mitochondria and they developed into the primary yolk globules with participation of large and dense pinocytotic vesicles. Yolk globules in mature oocyte were consisted of three components: the crystalline type main body, the superficial layer with dense and fine granules, and the limiting membrane. Steroid hormone secreting cells were recognized in the interstitial cells of growing testis. Numerous endoplasmic reticula and large mitochondria with well developed tubular cristae appeared in their cytoplasms. The axoneme in the tail flagellum of spermatozoon consisted of nine pairs of microtubules at the periphery and one pair at the center, and they were covered with doublet microtubules.

• 한국수산과학회지
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• 제36권2호
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• pp.157-162
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• 2003

Ultrastructure of germ cell during gametogenesis of surf clam, Spisula sachalinensis were investigated by electron microscopic observations. Oogonia are oval in shape and 5-6 ${\mu}m$ in diameter. They contain a large nucleus and have several mitochondria in the cytoplasm. Vitellogenic oocytes grew attached by a stalk to the germinal epithelium in the ovarian sac and their cytoplasm contained many yolk granules, lipid granules and mitochondria. Mature oocytes measuring 50-60 ${\mu}m$ in diameter have a nucleus containing an electron dense nucleolus, and a lots of yolk granules, lipid granules, mitochondria, rough endoplasmic reticulum and cortical granules were present in the cytoplasm. The surface of the plasma membrane in mature oocytes was formed of microvilli approximately 1.5 ${\mu}m$ long and enveloped in the vitelline layer. Spematogonia are oval in shape and about 5 ${\mu}m$ in diameter. Sprmatogonia develop into spermatocyte, spermatid and spermatozoon. The spermatozoon consisted of the head, midpiece and tail. The sperm head with diameter of about 1.5 ${\mu}m$ was ovoid, and contained the nucleus which consisted of acrosome. The four mitochondria encircled the centrosome in midpiece. The flagellum measuring about 40 ${\mu}m$ long had the classical 9+2 axoneme structure.

• Applied Microscopy
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• 제31권2호
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• pp.143-156
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• 2001

본 연구는 황소개구리의 정소내 생식세포분화 단계와 정자변태과정중의 정자의 형태적 특징을 알아보기 위하여 조사한 결과 다음과 같은 결론을 얻었다. 황소개구리의 정자형성과정 중 생식세포는 제1정원세포, 제2정원세포, 제1정모세포, 제2정모세포 및 정자세포로 구성되어져 있으며, 이들 생식세포의 분화단계는 세포의 형태적 특정을 기초로 하여 총 8단계로 구분되어졌다. 제1정원세포를 제외한 정모세포발생 단계에서부터 이탈 전까지의 정자세포는 정낭내에 존재하고 있었다. 정자변태과정은 3단계로 구분되어졌다. 성숙기의 정자의 첨체는 낭상이고, 두부의 모양은 양끝이 가는 원통형이었으며, 꼬리는 단지 축사로만 구성되어져 있었다.

• 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.

• Fisheries and Aquatic Sciences
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• 제9권1호
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• pp.1-6
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• 2006

Mature spermatozoa of dark chub Zacco temmincki (Temminck and Schlegel), were examined under a scanning electron microscope (SEM) and a transmission electron microscope (TEM). The spermatozoa have a spherical, homogeneously electron-dense nucleus with an axial nuclear fossa containing two laterally oriented centrioles. The centrioles, which are arranged at about a $120^{\circ}$ angle to each other, have the 9+2 microtubule structure typical of flagella. The mature spermatozoon is of the primitive anacrosomal aquasperm type. The nuclear envelope is strongly undulated and contains nuclear vacuoles of different sizes and positions. The midpiece contains six or more mitochondria and encircles the basal body of the flagellum with an axoneme covered by the plasma membrane. Cytoplasmic vesicles lie between the axonemal doublets and the plasma membrane, and encircle the anterior part of the tail. The plasma membrane of the flagellum extends laterally and forms a pair of side fins. The species showed minor differences in number and structure of mitochondria, the angle between centrioles, and total length and occurrence of the fins. These characters, especially the side fins, appear to be apomorphic and useful for determining phylogenetic relationships at the genus or family level.