• Development and Reproduction
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• v.15 no.3
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• pp.239-247
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• 2011

Spermatogenesis and taxonomic values of mature sperm morphology of in male Septifer (Mytilisepta) virgatus were investigated by transmission electron microscope observations. The morphologies of the sperm nucleus and the acrosome of this species are the cylinder shape and cone shape, respectively. Spermatozoa are approximately 45-50 ${\mu}m$ in length including a sperm nucleus (about 1.26 ${\mu}m$ long), an acrosome (about 0.99 ${\mu}m$ long), and tail flagellum (about 45-47 ${\mu}m$). Several electron-dense proacrosomal vesicles become later the definitive acrosomal vesicle by the fusion of several Golgi-derived vesicles. The acrosome of this species has two regions of differing electron density: there is a thin, outer electron-dense opaque region (part) at the anterior end, behind which is a thicker, more electron-lucent region (part). In genus Septifer in Mytilidae, an axial rod does not find and also a mid-central line hole does not appear in the sperm nucleus. However, in genus Mytilus in Mytilidae, in subclass Pteriomorphia, an axial rod and a mid-central line hole appeared in the sperm nucleus. These morphological differences of the acrosome and sperm nucleus between the genuses Septifer and Mytilus can be used for phylogenetic and taxonomic analyses as a taxonomic key or a significant tool. The number of mitochondria in the midpiece of the sperm of this species are five, as seen in subclass Pteriomorphia.

• Animal cells and systems
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• v.9 no.2
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• pp.65-73
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• 2005

In this study, we found that sperm ball of Urechis unicinctus consisted of a somatic cell and spermatogenic cells. After separation from the sperm ball, individual spermatid floated freely in the coelomic fluid and differentiated into a mature sperm. Because of many nuclear vacuoles, spermatid nucleus was observed to be heterogeneous. Later, the spermatid nucleus condensed into the homogeneous round nucleus of the mature sperm. Perinuclear microtubules could be seen but did not seem to be organized into manchette microtubules. To understand the nature of nuclear condensation during spermiogenesis, the sperm and spermatids (spermiogenic cells) were treated with FITC-phalloidin, or anti-actin-FITC, or labeled with antiactin immunogold particles (AAIP; 10 nm) followed by transmission electron microscopy or confocal laser scanning microscopy. The anti-actin-FITC and FITC-phalloidin reactions occurred distinctly in the nuclei of both spermiogenic cells. FITC-phalloidin reacted more intensely with acrosomes. The AAIP were incorporated mainly into nuclei of both cells sometimes showing local distribution in the nucleus. Nuclear vacuoles of spermatids disappeared progressively with condensation of the nucleus, as the number of incorporated $AAIP/{\mu}m^2$ increased. These results suggest that nuclear actin microfilaments might be closely related to nuclear condensation.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.41-41
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• 2001

Chromatin configuration and microtubule assembly were determined in porcine maturing and activated oocytes following intracytoplasmic sperm injection. Microtubule localization was confirmed using a mouse monoclonal antibody to $\alpha$-tubulin and detected using a fluorescent labeled goat anti-mouse secondary antibody. DNA was stained with propidium iodide. The image of microtubules and chromatin was captured using laser scanning confocal microscope. In germinal vesicle stage oocyte, sperm chromatin remained condensation and sperm derived microtubules were not observed at 8 to 12 h after sperm injection. At 24 h after injection, the sperm nucleus developed to the metaphase chromatin along the metaphase structure of female nucleus. In some metaphase I stage oocytes, sperm chromatin decondensed at 8 h to 12 h after injection, sperm aster was seen soon after sperm injection. At 24 h after sperm injection into metaphase I stage oocyte, male chromatin developed to the metaphase chromatin while female chromatin extruded first polar body and formed the metaphase chromatin. At 12 to 15 h after sperm injection into preactivated oocytes, condensed sperm nucleus was located in close proximity of female pronucleus. However, the condensed nucleus did not fuse with female pronucleus. In preactivated ocytes, injected sperm remained condensation, a few sperm organized small microtubular aster. Instead, maternal derived microtubules were organized near the female chromatin, which seem to move condensed male chromatin near to the female pronucleus. These results suggest that sperm nuclear decondensing activity and nucleation activity of centrosome during fertilization are cell cycle dependent. In absence of male functional centrosome, female origin centrosome takes over the role of microtubule nucleation for nuclear movement.

• The Korean Journal of Malacology
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• v.27 no.4
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• pp.377-386
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• 2011

The ultrastructures of germ cells during spermatogenesis and sperm morphology in male Mya arenaria oonogai, which was collected on the coastal waters of Samcheonpo, south coast of Korea, were investigated by transmission electron microscopic observations. In the early stage of the spermatid during spermiogenesis, a few granules and a proacrosomal granule, which is formed by the Golgi complex, appear on the spermatid nucleus, and then it becomes a proacrosomal vesicle. Consequently, it becomes an acrosome by way of the process of acrosome formation. The morphologies of the sperm nucleus type and the acrosome of this species have a curved cylindrical type and cone shape, respectively. The spermatozoon is approximately $48-50{\mu}m$ in length including a curved cylinderical sperm nucleus (about $2.65{\mu}m$ long), an acrosome (about $0.64{\mu}m$ in length) and tail flagellum ($40-45{\mu}m$ long). As some ultrastructural characteristics of the acrosomal vesicle, the peripheral parts of two basal rings show electron opaque part (region), while the apex part of the acrosome shows electron lucent part (region). These charateristics of the sperm belong to the family Myidae or some species of Veneridae in the subclass Heterodonta, unlike a characteristic of the subclass Pteriomorphia showing all part of the acrosome being composed of electron opaque part (region). Therefore, it is easy to distinguish the families or the subclasses by the acrosome structures. Exceptionally, In particular, a cylinder-like nucleus of the sperm is curved (the angle of the nucleus is about $20^{\circ}$), as seen in some species of Veneridae (range from $0^{\circ}-80^{\circ}$). The number of mitochondria in the midpiece of the sperm of this species are four, as one of common characteristics appeared in most species except for a few species in Veneridae in the subclass Heterodonta. Cross-sectioned axoneme of the sperm tail flagellum shows a 9+2 structure: the axoneme of the sperm tail flagellum consists of nine pairs of peripheral microtubules at the periphery and a pair of central doublets at the center.

• The Korean Journal of Malacology
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• v.26 no.1
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• pp.33-43
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• 2010

The ultrastructure of germ cells during spermatogenesis and some characteristics of sperm morphology in male Mytilus coruscus, which was collected on the coastal waters of Gyeokpo in western Korea, were investigated by transmission electron microscope 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 five mitochondria surrounding the centrioles. The morphologies of the sperm nucleus type and the acrosome shape of this species have an oval and modified cone shape, respectively. In particular, the axial rod is observed between the nucleus and acrosome of the sperm. The spermatozoon is approximately $45-50{\mu}m$ in length including a sperm nucleus (about $1.46{\mu}m$ in length), an acrosome (about $3.94{\mu}m$ in length) and tail flagellum (approximately $40-45{\mu}m$). 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. Some special charateristics of sperm morphology of this species in the genus Mytilus are (1) acrosomal morphology, (2) the number of mitochondria in the midpiece of the sperm, and (3) the existence of a satellite. The axial rod appears in the acrosome and sperm nucleus as one of the characteristics seen in several species of the subclass Pteriomorphia, unlikely the subclass Heterodonta containing axial filament instead of the axial rod. The number of mitochondria in the midpiece of the sperm of this species in the family Mytilidae are five, as one of common characteristics appeared in most species in the family Mytilidae. Most of Mytilus species contain a satellite body which is attached to the proximal centriole in the middle piece of the sperm, as one of common characteristics of sperm morphology in the family Mytilidae.

• Development and Reproduction
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• v.17 no.2
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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.

• The Korean Journal of Malacology
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• v.30 no.3
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• pp.211-218
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• 2014

Spermatid differentiations during spermiogenesis and sperm ultrastructures in male Mercenaria stimpsoni were investigated by transmission electron microscopic observations. In the early stage of the spermatid during spermiogenesis, a few granules and a proacrosomal granule, which is formed by the Golgi complex, become a proacrosomal vesicle. Consequently, it becomes an acrosome by way of the process of acrosome formation. The morphologies of the sperm nucleus type and the acrosome of this species have a curved cylindrical type and cap shape, respectively. The spermatozoon is approximately $48-51{\mu}m$ in length including a curved cylinderical sperm nucleus (about $4.18{\mu}m$ long), an acrosome (about $0.52{\mu}m$ in length) and tail flagellum ($42-45{\mu}m$ long). As some ultrastructural characteristics of the acrosomal vesicle, the peripheral parts of two basal rings show electron opaque part (region), while the apex part of the acrosome shows electron lucent part (region). These charateristics of the 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 (region). Therefore, it is easy to distinguish the families or the subclasses by the acrosome structures. Exceptionally, In particular, a cylinder-like nucleus of the sperm is curved (the angle of the nucleus is about $80^{\circ}$), as seen in some species of Veneridae (range from $0^{\circ}$ to $80^{\circ}$). The number of mitochondria in the midpiece of the sperm of this species are four, as one of common characteristics appeared in most species except for a few species in Veneridae in the subclass Heterodonta. Cross-sectioned axoneme of the sperm tail flagellum shows a 9+2 structure.

• 대한생식의학회:학술대회논문집
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• 2001.11a
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• pp.57-62
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• 2001

One of recent advances of mammalian fertilization is the understanding of the molecular basis of fertilization. Several proteins localized in sperm nucleus or on sperm surface are necessary for the fertilization process. Protamines, sperm nuclear proteins, are required for normal sperm function that leads to fertilization. Fertilin and cyritestin are sperm surface proteins and essential for sperm-egg binding. Fertilin is also required for sperm transport in the female reproductive tracts. Metalloproteses on sperm plasma membrane are found to play a role in sperm-egg fusion. The functional analysis of these proteins provides a new insight into the molecular mechanisms underlying mammalian fertilization and male fertility.

• The Korean Journal of Malacology
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• v.27 no.1
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• pp.55-65
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• 2011

Some characteristics of germ cell differntiations during spermiogenesis and mature sperm ultrastructure in male Phacosoma japonicus were investigated by transmission electron microscope observations. The morphology of the spermatozoon of this species has a primitive type and is similar to those of other species in the subclass Heterodonta. Morphologies of the sperm nucleus and the acrosome of this species are the cylindrical type and cap shape, respectively. The spermatozoon is approximately 45-50 ${\mu}m$ in length, including a long curved sperm nucleus (about $3.70{\mu}m$ long with 45 $^{\circ}$ of the angle of the nucleus, an acrosome (about $0.55{\mu}m$ in length), and tail flagellum (about 42-$47{\mu}m$)The axoneme of the sperm tail shows a 9+2 structure. As some characteristics of the acrosomal vesicle structures, the basal and lateral parts of basal rings show electron opaque part (region), while the anterior apex part of the acrosomal vesicle shows electron lucent part (region). These characteristics of the acrosomal vesicle were found in the family Veneridae and other several families in the subclass Heterodonta. These common characteristics of the acrosomal vesicle in the subclass Heterodonta can be used for phylogenetic and systematic analysis as a taxonomic key or a significant tool. The number of mitochondria in the sperm midpiece of this species are four, as one of common characteristics appear in most species in the family Veneridae and other families in the subclass Heterodonta. However, exceptionally, only three species in Veneridae of the subclass Heterodonta contain 5 mitochondria. The number of mitochondria in the sperm midpiece can be used for the taxonomic analysis of the family or superfamily levels as a systematic key or tools.

• Applied Microscopy
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• v.44 no.1
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• pp.1-7
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• 2014

The spermatogenesis of Siamese fighting fish, Betta splendens, belongs to Osphronemidae was investigated by light and electron microscopic observations. In primary spermatocyte stage, the nucleus was comparatively large ellipsoidal, and mitochondria showed a marked development in cytoplasm. In secondary spermatocyte stage, the germ cells were smaller than that of primary spermatocytes. The nucleus was a spherical shape and intercellular space was formed between germ cells. In spermatid stage, the early spermatids were not much different from a secondary spermatocyte. But, the chromatin condensation was occurred from the outside to the inside. The nucleus was more condensed. Intracellular space was larger than early spermatid. The mitochondria were rearranged in a middle piece, and occupied about half of the head part in early sperm. In sperm stage, the head of mature sperm was a spherical shape and had no acrosome. The flagellum was showed the typical 9+2 array of microtubules. Also, the tail of sperm had no lateral fins and outer coarse fibers. These ultrastructural characteristics can be used in classification of species.