• Proceedings of the Korea Society of Poultry Science Conference
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• 2001.11a
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• pp.69-70
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• 2001

Lectins have great potential as to determine the alternation of the distribution of cell surface carbohydrates during cellular development and differentiation. Here, we investigated the presence and distribution of cell surface carbohydrates on chicken primordial germ cells (PGCs) during the migration and gonadal stages using a variety of lectins. A total of six FITC-labelled lectins from several specificity classes were used: ConA (glucose/mannose), WGA (N-acetylglucosamine), STA (N-acetylglucosamine), DBA (N-acetylgalactosamine/galactose), UEA-I (fucose) and PHA-E (oilgosaccharide). As a results, PGC-specific binding was observed in STA. PGCs of migration stage (2.5- and 5.5-day embyos) were STA-positive whereas PGCs of 10-day embryonic gonad were not. The results suggest that N-acetylglucosamine residuse are present specifically in migrating chicken PGCs and changes during development.

• Clinical and Experimental Reproductive Medicine
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• v.50 no.4
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• pp.213-222
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• 2023

Cryopreservation is an option for the preservation of pre- or post-pubertal female or male fertility. This technique not only is beneficial for human clinical applications, but also plays a crucial role in the breeding of livestock and endangered species. Unfortunately, frozen germ cells, including oocytes, sperm, embryos, and spermatogonial stem cells, are subject to cryoinjury. As a result, various cryoprotective agents and freezing techniques have been developed to mitigate this damage. Despite extensive research aimed at reducing apoptotic cell death during freezing, a low survival rate and impaired cell function are still observed after freeze-thawing. In recent decades, several cell death pathways other than apoptosis have been identified. However, the relationship between these pathways and cryoinjury is not yet fully understood, although necroptosis and autophagy appear to be linked to cryoinjury. Therefore, gaining a deeper understanding of the molecular mechanisms of cryoinjury could aid in the development of new strategies to enhance the effectiveness of the freezing of reproductive tissues. In this review, we focus on the pathways through which cryoinjury leads to cell death and propose novel approaches to enhance freezing efficacy based on signaling molecules.

• The Korean Journal of Malacology
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• v.26 no.3
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• pp.235-244
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• 2010

Ultrastructural characteristics of the testis and spermatogenesis of Crassostrea gigas were investigated by Transmission and Scanning Electron microscope observations. The testis is a diffuse organ consisting of branching acini containing differentiating germ cells in a variety of stages. The acinus is surrounded by an intermitent layer of myoepithelial cells andis divided into subcompartments that are partially separated by pleomorphic accessory cells which remain in close contact with germ cells until late stages of development. these accessory cells contain a large quantity of glycogen particles and lipid droplets in the cytoplasm. Therefore, it is assumed that they are involved in the supplying of the nutrients for germ cell development, while any phenomena associated with phagocytosis of undischarged, residual sperms by lysosomes could be find in the cytoplasm of the accessory cells. The morphology of the spermatozoon has a primitive type and is similar to those of other bivalves. Mature spermatozoa consist of broad, cap-shaped acrosomal vesicle, subacrosomal material (containing axial rod embedded in a granular matrix), a oval nucleus showing deeply invaginated anteriorly, two triplet substructure centrioles surrounded by four spherical mitochondria, and satelite fibres appear to the distal centriole and plasma membrane. Spermatozoa of C. gigas resemble to those of other investigated ostreids. In particular, the anterior region of the acrosomal vesicle is transversely banded. It is assumed that differences in this acrosomal substructure are associated with the inability of fertilization between the genus Crassostrea and other genus species in Ostreidae. Therefore, we can use sperm morphology in the resolution of taxonomic relationships within the Ostreidea. The spermatozoon is approximately $42-47{\mu}m$ in length including an oval sperm nucleus (about $0.91{\mu}m$ in length), an acrosome (about $0.42{\mu}m$ in length) and tail flagellum ($40-45{\mu}m$). 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. These morphological charateristics of acrosomal vesicle belong to the family Ostreidae in the subclass Pteriomorphia.

• Proceedings of the KSAR Conference
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• 2003.06a
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• pp.97-97
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• 2003

For many animals the centrosome consists of a pair of centrioles and surrounding pericentriolar materials (PCMs). PCMs have been known to play roles during cell division. It is known that centrioles are necessary to assemble centrosomal components. However, many types of oocytes undergo meiosis without centrioles. It is known that in nonmurine mammalian species, the sperm introduces an intact proximal centriole unlike sea urchin where two centrioles are introduced. In case of mouse sperm, the presence of centrosome is not clear In this study, a monoclonal antibody was developed to investigate centrosome during mouse germ cell and early embryo development. Results of immunostaining and Western blotting in CHO cells suggest that the monoclonal antibody recognizes a nuclear and centrosomal protein, thus called NCP. The NCP monoclonal antibody was used to screen a cDNA expression library prepared from 12.5 mouse brain to isolate NCP gene. Nucleotide size of NCP gene obtained from immunoscreening was about 5.5kb. It is determined that the NCP may be closely related with pericentriolar material -1 gene (Pcm-1) from the result of sequencing analysis. The molecular weight, 66kDa, calculated by known DNA sequence in database is consistent with that of detected from Western blotting using CHO cell lysates. Therefore, it is assumed that NCP may be alternative splicing form of Pcm-1 of which molecular weight is 228kDa. In mouse oocytes, NCP was distributed in nucleus as in CHO cells. It was shown that the NCP was localized around neck region, probably the centrosome in mouse neck region. Interestingly, dramatic change in distribution of NCP was also shown in male germ cell development. Finally, we observed the cellular distribution of NCP during early embryo development. NCP was detected in nucleus as well as centrosome foci. It is suggested that the centrioles reassembly we occurring in blastocysts and then affects the distribution of NCP.

• Development and Reproduction
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• v.8 no.1
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• pp.27-33
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• 2004

To investigate the mechanism of germ cell death in postnatal stage of mouse, the involvement of apoptotic executioners, caspase-3 and caspase-activated DNase(CAD), and apoptotic initiators, Bax Fas and Fas ligand, in the germ cell death has been studied. Immune-labels of active caspase-3 and CAD were located in TUNEL-positive, apoptotic, oocytes as well as normal oocytes of primary or secondary follicles. CAD immune-labels were also detected in the nucleus of TUNEL-positive oocytes. Most of oocytes showing positive immune-labeling of active caspase-3 or CAD had vacuoles in their cytoplasm, which is the morphological characteristic of oocyte during folliclar atresia. Bax immune-stains were detected in the atretic oocytes which showed the vacuole in their cytoplasm. Positive immune-labels for Fas ligand was localized in TUNEL-positive or atretic oocytes. Presence of immunoreactivity of active caspase-3 and CAD in TUNEL-positive germ cells implicate that active raspase-3 and CAD might play a role in germ cell apoptosis during early development of mouse ovarian follicle. Immunohistochemical localization of Bax and Fas ligand in TUNEL-positive oocytes suggests that these might be the most plausible modulator of oocyte apoptosis.

• Development and Reproduction
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• v.14 no.1
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• pp.7-11
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• 2010

This study attempted to verify the possibility of using germ cell aspiration (GCA) method as a non-fatal technique in studying the life-history of equilateral venus, Gomphina veneriformis (Veneridae) and granular ark, Tegillarca granosa (Arcidae). Using twenty-six gauge 1/2" (12.7mm) needle, GCA was carried out in equilateral venus through external ligament. In granular ark, GCA was performed by preventing closure of the shells by inserting a tongue depressor between the shells while still open. The success rate of sex identification using the GCA method was 95.6% for the equilateral venus (n=650/680) and 94.3% for the granular ark (n=707/750). Mortality of equilateral venus, which spent 33 days under wild conditions, was 13.8% (n=90/650) while the mortality of granular ark, which spent 390 days under wild conditions, was 2.4% (n=17/707). Although we believe that GCA does not appear to cause death in equilateral venus or granular ark, the success rate in employing of this methodology may differ depending on the level of proficiency of the researcher and reproductive stage of the bivalve. This study concludes that GCA is a convenient non-fatal methodology, which can be employed to identify sex and investigate gonadal maturity in Gomphina veneriformis and Tegillarca granosa.

• The Korean Journal of Malacology
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• v.31 no.1
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• pp.9-19
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• 2015

Germ cell development and cyclic changes in the epithelial cells of the seminal vesicle of the male rapa whelk, Rapana venosa, were investigated by cytological and histological observations. The process of germ cell development can be classified into five stages: (1) spermatogonial, (2) primary spermatocyte, (3) secodary spermatocyte, (4) spermatid, and (5) spermatozoon. In particular, four atypical cells (Type IA, IB, IIA and IIB cells) occur among normal germ cells in the acini during spermatogenesis. Presumably, the atypical cells, which have lysosome-like vacuoles or lysosome-like bodies in the cells, are involved in breakdown and absorption themselves in the acini. However, atypical cells were not found in the epithelial cells of the inner layer of the seminal vesicle. A considerable amount of spermatozoa are transported from the testis towards the the seminal vesicles until late July. The main coupulation period is between June and July. The process of the cyclical changes of the seminal vesicles can be classified into three phases: (1) resting, (2) accumulating, and (3) spent. Yellow granular bodies are involved in resorption or digestion of residual spermatozoa.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1998.06a
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• pp.167.1-168
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• 1998

• The Korean Journal of Malacology
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• v.22 no.1 s.35
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• pp.39-49
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• 2006

Ultrastructure of germ cell differentiation during supermatogenesis and the reproductive cycle in male Patinopecten yessoensis was studied by histological and cytological observations. The gonadosomatic index (GSI) in males rapidly increased and reached a maximum in April when seawater temperature gradually increased. Then the GSI gradually decreased from May through July when spawning occurred. Accordingly, monthly changes in the GSI in males coincided with testicular maturation and spawning periods. The sperm morphology of P. yessoensis belongs to the primitive type and showed general characteristics of external fertilization species. The head of the spermatozoon is approximately $3.50{\mu}m$ in length: the sperm nucleus and acrosome are approximately $2.90{\mu}m\;and\;0.60{\mu}m$ in length, respectively. The nuclear type of the spermatozoon is vase in shape, and the acrosome is cone type. The axoneme of the tail flagellum consists of nine pairs of microtubules at the periphery and a pair of central microtubules in the center The satellite body (which is formed by the centriole) and four mitochondria appear in the middle piece of the spermatozoon. The spawning period was from April through July and the main spawning occurred from May to June when seawater temperatures gradually increased. The reproductive cycle of this species can be classified into five successive stages; early active stage (September to November), late active stage (October to March), ripe stage (February to August), spawning stage (April to July), and spent/inactive stage (July to November).

• Fisheries and Aquatic Sciences
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• v.6 no.2
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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.