• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.30 no.6
• /
• pp.1005-1012
• /
• 1997

Fine structural changes of the germ cells during spermatogenesis in the goldeye rockfish, Sebastes thompson; were examined by means of the transmission and scanning electron microscopy. A spermatogonium has a large nucleus with a single nucleolus in the interphase. Primary spermatocytes are characterized by the formation of chromatin clumps and presence of the synaptonemal complex in the nucleus. The nucleoplasm of secondary spermatocytes is more condensed than that of primary spermatocytes, and the cytoplasm contains numerous mitochondria, endoplasmic reticulum and Golgi complex. The nuclei of spermatids in metamorphosis show sickle-like shape as the nucleoplasm becomes more condensed. In the cytoplasm of spermatids, the proacrosomal granules are not found at all. A spermatozoon consists of head, neck and tail. The acrosome is absent in the head. Four to five cytoplasmic collars are observed in the posterior portion of the head of spermatozoon. The well developed axonemal lateral fins are observed in the flagellum of spermatozoon.

• Korean Journal of Ichthyology
• /
• v.21 no.2
• /
• pp.81-86
• /
• 2009

The spermiogenesis and mature spermatozoa of Pseudobagrus fulvidraco were described by means of scanning and transmission electron microscopy. Spermiogenesis is characterized by lateral development of the flagellum, nuclear rotation, deep nuclear fossa formation and compaction into thick granules. The spermatozoa exhibit a round head containing a nucleus that lacks an acrosome, and having a midpiece and a flagellum. The midpiece is small and has a short cytoplasm including several mitochondria separated from the tail by the cytoplasmic canal. The flagellum contains the 9+2 classical axoneme structure and has two axonemal fins. The presence of axonemal fins in the flagellum is a common character in Bagridae. The interrelationships among the Bagridae as well as other teleosts are herein discussed.

• Applied Microscopy
• /
• v.29 no.4
• /
• pp.427-435
• /
• 1999

Spermatogenesis and fine structure of the spermatozoon of the marbled sole, Limanda yokohamae were examined by means of the scanning and transmission electron microscopy. The process of spermatogenesis of the marbled tole is similar to that of other teleost with external fertilization. During the spermiogenesis, chromatin that has been became fine]y granular progressively condenses into many large globules and that homogeneously condensed in the spermatozoan head. A spermatozoon consists of head and tail, and the acrosome is absent. The cytoplasmic collar contained eight mitochondria is observed in the posterior part of the head. The well -developed axonemal lateral fins are observed in the tail. In the TEM observation, the cross section of the axial filament shows '9+2' axonemal structure of microtubules, and the numerous vesicles are observed in the cytoplasm.

• Applied Microscopy
• /
• v.26 no.3
• /
• pp.267-275
• /
• 1996

The internal ultrastructural changes of germ cells and external morphology of spermatozoon during the spermatogenesis in the rockfish, Sebastes inermis were studied using transmission and scanning electron microscope. The testis is seminiferous tubule type in internal structure. Seminiferous tubule consist of many cyst which contain numerous germ cells in same developmental stage. Spermatogonium contained a large nucleus with single nucleolus in interphase. Primary spermatocyte identified by the presence of synaptonemal complex in nucleus and the contained a number of mitochondria, endoplasmic reticula and Golgi bodies in cytoplasm. The nucleoplasm of secondary spermatocyte was more concentrated than that of the previous phase. Spermatids were more condensed in nucleus and cytoplasm, and show the long-spherical shape. In the cytoplasm of spermatid mitochondria located to lower portion of the nucleus and Golgi bodies located to upper portion, but proacrosomal granule is not appeared. The spermatozoon consist of the head and tail. No acrosome could be found in the head. The cytoplasmic collar of posterior part in sperm head contained mitochondria which surrounded axial filament. The well developed axonemal lateral fins were identified in sperm flagellum, and the axial filament of the flagellum consist of nine pairs of peripheral microtubules and one pair of central microtubules.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.6
• /
• pp.730-736
• /
• 1999

The roundnose flounder's (Eopsetta grigorjewi) spermiogenesis and fine structure of the spermatozoon were examined by means of the scanning and transmission electron microscopy, During the spermiogenesis, the chromatin of the spermatid became fine granular form, and progressively condensed into many large globules, finally homogeneously condensed in the spermatozoan head. The main characteristics of the spermiogenesis were the disappearanre of Golgi complex, the appearance of microfilament the reduction of mitochondria and the appearance of Iysosome in the cytoplasm. A spermatozoon consisted of head and tail, but the acrosome was absent. The cytoplasmic collar containing seven mitochondria was observed in the posterior part of the head. The well-developed axonemal lateral fins were observed in the tail. The cross section of the axial filament showed '9+2' axonemal structure of microtubules, and the numerous vesicles were observed in the cytoplasm.

• Applied Microscopy
• /
• v.42 no.2
• /
• pp.61-66
• /
• 2012

Ultrastructural characteristics of blacktip grouper, Epinephelus fasciatus spermatozoa were investigated using transmission and scanning electron microscopy. The spermatozoa of E. fasciatus consisted of a spherical head part, a midpiece with cytoplasmic canal entrance and a flagellum with lateral fins. Internal ultrastructurally, the nucleus contains high electron dense chromatin having granular particles and has no acrosome. The centriolar complex lies outside of the nuclear fossa and it is connected by the osmophilic filaments. Also the osmophilic filaments connect between the centriolar complex and the nuclear membrane. The midpiece contains eight to nine spherical mitochondria, cytoplasmic canal and necklaces. The flagellum has a typical 9+2 axonemal structure. The lateral fins contain vesicles and a typical 9+2 axonemal structure. Consequently this study contributes to comparative grouper spermatology and provide useful systematic taxonomic characters.

• Korean Journal of Ichthyology
• /
• v.18 no.4
• /
• pp.347-354
• /
• 2006

Spermiogenesis in the Zacco koreanus is characterized by lateral development of flagellum, shallow nuclear fossa formation and with no nuclear rotation. These spermatozoa exhibit a spherical head containing a nucleus with the chromatin highly condensed and no acrosome. The midpiece is a small and a short cytoplasmic canal. Mitochondria are separated from the initial segement of the axoneme by cytoplasmic canal. The flagellum contains the classic axoneme structure (9+2) and has a vesicle in the initial region; it dose not have axonemal fins. The presence of a vesicle in the initial region of flagella, a structure common in many Cypriniformes spermatozoa.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.37 no.4
• /
• pp.281-286
• /
• 2004

Spermatogenesis and sperm ultrastructure of the marsh clam (Corbicula japonica) were investigated by electron microscopic observations. Testis of the marsh clam consists of numerous spermatogenic follicle containing germ cells in the different developmental stages. Spermatogonia are located nearest the outer wall of the follicle, while spermtocytes and spermatids are positioned nearer to the lumen. Spematogonia are oval-shaped and about $5{\mu}m$ In diameter. Spermatogonia develop into spermatocyte, spermatid and spermatozoon. In the spermatid to about $2{\mu}m$ in diameter, cytoplasm decreases and mitochondria move to the base of the nucleus and fuse into several spheres, the centrioles become orthogonally oriented, a flagellum appears, and an acrosomal vesicle forms. The mature sperm has primitive type, consisting of a head, a midpiece and a tail. The sperm was arrow-shaped, and its head is about $8{\mu}m$ long and comprised of a long nucleus and an acrosome. The four mitochondria encircled the centrosome in midpiece. The flagellum had the classical 9+2 axoneme structure, and axonemal lateral fins in the tail were observed.

• Korean Journal of Ichthyology
• /
• v.18 no.4
• /
• pp.311-318
• /
• 2006

Ultrastructure of germ cells, the cyst epithelial cells and interstitial cells during spermatogenesis of the stone flounder, Kareius bicoloratus (Pleuronectidae) sampled on the west coast of Korea were investigated by electron microscopic observations. In the primary spermatocyte, the synaptonemal complexes appear in the zygotene stage of the prophase during maturation division. In the growing testis, especially, the interstitial cells (Leydig cells) appear near the primary, secondary spermatocytes and spermatids. Well-developed interstitial cells (steroid hormone secreting cells) which are located in the interlobular space in growing testis have three morphological characteristics of a vesicular nucleus, mitochondria with tubular cristae and smooth endoplasmic reticulum. During spermatogenesis, the primary and secondary spermatocytes attach to the cyst epithelial cell (Sertoli cell) having an elongated ovoid or triangular nucleus and several mitochondria in the cytoplasm. In the growing testis, lipid droplets, the mitochondrial rosettes and glycogen particles appear in the cytoplasm of the cyst epithelial cells near the secondary spermatocytes and spermatids. Particularly, the mitochondria, endoplasmic reticulum, little lipid droplets and the large amount of glycogen particles are present in the cytoplasm of the cyst epithelial cell in the late growing testis. In the late stage of spermiogenesis, the proximal centriole is joined to the nuclear envelope, the distal centriole forms the basal body of the flagellum and gives rise to the axial filament of the flagellum. No acrosome of the sperm is formed as seen in other teleost fish. The head of the spermatozoon is approximately $3{\mu}m$ in length and its tail is about $30{\mu}m$ in length. The axoneme of the tail flagellum of the spermatozoon consists of nine outer doublet microtubules at the periphery and two centrial singlet microtubules at the center. The spermatozoon of this species has two axonemal lateral fins. Especially, the cyst epithelial cells which located near groups of gametes in the various stages, show three functions: nutrition, phagocytosis and steroidogenesis. Especially, the nuclei of cyst epithelial cells in the recovery stage of the testicular developmental stages appear to be irregular in shape after spermiation. Of three functions of the cyst epithelial cell, several characteristics of phagocytosis are showed in the cytoplasm of the cyst epithelial cells in the recovery stage of the testicular developmental stages. At this stage, therefore, it is assumed that the cyst epithelial cells are involved in degeneration and resorption of undischarged germ cells after spermiation.