• Proceedings of the Korean Aquaculture Society Conference
• /
• 2006.05a
• /
• pp.667-669
• /
• 2006

• Proceedings of the Korea Environmental Mutagen Society Conference
• /
• 2002.05a
• /
• pp.96-96
• /
• 2002

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

• The Korean Journal of Malacology
• /
• v.27 no.4
• /
• pp.377-386
• /
• 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
• /
• v.26 no.1
• /
• pp.33-43
• /
• 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.

• Reproductive and Developmental Biology
• /
• v.28 no.1
• /
• pp.65-70
• /
• 2004

In mammals, male and female germline stem cells are derived from primodial germ cells. Despite many efforts to identify stem cells from gonads, there has been little successe to identify germline stem cells yet. In this study, we isolate and characterized porcine germline stem cells using only stem cell markers that are prevalently expressed in various tissues. Gonadal cells derived from both male and female formed colonies and showed AP activities and different lectin binding properties. Pluripotency of germline stem cells was also identified by positive signals against putative stem cells markers such as SSEA-1 and SSEA-3. In addition, nestin was also found in primary gonad cells that have a similar morphology to the AP-positive cells. The nestin expression suggests that the germline stem cells may have similar expression of the prevalent stem cell markers found in other tissues. The demonstration of nestin expression together with pluripotent cell markers calls further investigation of the possible differentiation of nestin-positive cells into neurons.

• Journal of Plant Biotechnology
• /
• v.1 no.1
• /
• pp.56-60
• /
• 1999

Sexual reproduction is an essential process in the propagation of flowering plants. Recent advances in plant cell biology and biotechnology have brought new and powerful methodologies to investigate and manipulate the reproductive processes of angiosperms including agronomically important crop plants. Successful cryopreservation of maize, rye and triticale pollen and young embryos of microspore-and zygote-origine contributes to long term preservation of important plant germ-lines in gene banks. Discovering morphogenetic characteristics of the different developmental pathways taking place in wheat and maize androgenesis in vitro helps to influence the procedure to produce genetically and phenotipically stable homozygous doubled haploid plants for breeding purposes. Detailed ultrastructural and cell-biological studies on the developmental sequences of male and female gametophyte development in wheat, experimental protocols developed to isolate and micromanipulate egg cell protoplasts, make it possible to use plant gametes and the sexual route itself to produce genetically improved organisms. Plant gametes can become useful tools for crop improvement in the near future. Recent achievements by our laboratory in this field are reviewed in the present paper

• Toxicological Research
• /
• v.17 no.4
• /
• pp.267-272
• /
• 2001

This study was carried out to assess the reproductive toxicity of 2-bromopropane (S-BP) using spermatogenesis stage classification and Sertoli cell indices (SCI).Vehicle control olive oil and 2-BP doses of 125, 250 and 500 mg/kg of body weight were injected in the interaperitoneum of 12 weeks male Sprague-Dawley rats for 28 days respectively of SCI on germ cells including the spermatogonia of stages II-III, Ⅵ,Ⅹ, XII, ⅩIII, and spermatocytes of stages VIII (preleptotene), Ⅹ (leptotene), XII (leptotene), V and Ⅵ (pachytene), and the round spermatids of stage Ⅵ. Considering the process of maturation depletion in spermatonesis, spermatogonia may be the primary target cells of 2-BP toxicity.

• The Korean Journal of Malacology
• /
• v.27 no.3
• /
• pp.273-282
• /
• 2011

The ultrastructural characteristics of germ cells during spermatogenesis and mature sperm morphology in male Pinctada martensii were investigated by transmission electron microscope observation. The morphologies of the sperm nucleus and the acrosome of this species are the oval shape and cone shape, respectively. Spermatozoa are approximately $47-50{\mu}m$ in length including a sperm nucleus (about $1.24{\mu}m$ in length), an acrosome (about $0.60{\mu}m$ in length), and tail flagellum (about $45-47{\mu}m$). The axoneme of the sperm tail shows a 9+2 structure. In P. martensii in Pteriidae, a special substructure showing a thick and wide triangular shape which is composed of electron-dense opaque material (occupied about 50% of all, the upper part of the acrosomal vesicle), appeared in the upper region (part) of the acrosomal vesicle, while the lower region (part) of the acrosomal vesicle is composed of electron-lucent material. Thus, this special structure, which exist in the upper part of the acrosomal vesicle in P. martensii, is somewhat different from those of other subacrosomal vesicle in other families in subacrosomal vesicles. Therefore, we assume that the existence of a special substructure showing a thick and wide triangular shape in the acrosomal vesicle of the spermatozoon can be used as a key characteristic for identification of P. martensii or other species in Pteriidae in subclass Pteriomorphia. The number of mitochondria in the midpiece of the sperm of this species are five (exceptionally sometimes four), as one of common characteristics appear the same number of mitochondria in the same families of superfamilyies. This species in Pteriidae does not contain the axial rod and satellite fibres which appear in the species in Ostreidae in subclass Pteriomorphia. These characteristics can be used for the taxonomic analysis of the family or superfamily levels as a systematic key or tools.

• Applied Microscopy
• /
• v.33 no.3
• /
• pp.243-250
• /
• 2003

Ultrastructural changes of the male germ cells and structure of spermatozoa in Paralichthys olivaceus were examined by means of the light and transmission electron microscopes. The spermatogonium has a large nucleus with a single nucleus with a single nucleolus in the interphase. Primary spermatocytes are identified by the formation of the synaptonemal complex in the karyoplasm. The secondary spermatocytes are more concentrated and contains numerous cell organelle in the cytoplasm. The nucleus of spermatid in spermiogenesis is more condensed in the karyoplasm, and show spherical structure in shape. Mitochondria of the spermatids are observed in the lower portion of the nucleus. The spermatozoon consists of the head, mid piece and tail. The acrosome is not observed in the head. Axial filaments of the flagellum consists of nine pairs of the peripheral microtubules and one pair of the central microtubules.