• Korean Journal of Environmental Biology
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• v.35 no.2
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• pp.160-168
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• 2017

Tscherskia triton is widely distributed in Northern China, Korea, and the adjacent areas of Russia. Except its distribution, reproduction, and growth development related to life history, reproductive cycle and reproductive organs of T. triton are rarely studied in Korea. The purpose of this study was characterized the estrous cycle of T. triton captured in Jeju Island in order to provide information to a better information of captive breeding of the species when long-day (16L : 8D) and short-day (8L : 16D) photoperiod. Then, histological study of the ovaries and uterus with five females in each photoperiod was performed. The duration of the estrus cycle was 4~5 days and it showed regular cycle pattern. Results of the vaginal cytology examination showed four characteristic phase of the estrous cycle in long-day photoperiod (16L : 8D): proestrus, estrus, metestrus and diestrus. However, in short-day photoperiod, the diestrus phage of the estrus cycle was maintained from the $6^{th}$ to $12^{th}$ day. In the long-day photoperiod, females had many Graafian follicles and corpus luteums in large ovaries, and developed uterine glands in the thick endometrium. But they had some primary, secondary and tertiary follicles, and undeveloped uterine glands in the thin endometrium during short-day photoperiod. These results were identified difference of the estrus cycle and histological characteristics of reproductive tracts according to the photoperiod. These results are very important clues to the reproductive biology of T. triton, and it will be widely used as date for maintaining biodiversity.

• Proceedings of the Korea Society of Poultry Science Conference
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• 1999.11a
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• pp.11-33
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• 1999

This study was conducted to determine the embryonic stages for the isolation of the highest number of PGCs and to improve PGCs enrichment method. The primordial germ cells(PGCs) from different sources of chick embryos were isolated. The embryonic stage having the highest number of PGCs from each sources was selected ; 1-day-old embryos for germinal crescent (stage 6-8), 2.5-day-old embryos for blood (stage 17-18) and 5.5-day-old embryos for gonad (stage 27-28). The number of PGCs from one embryonic germinal crescent, blood and gonad was about 87$\pm$1.8, 103$\pm$4.0, and 932$\pm$10.9, respectively. The viability of PGCs after Ficoll from each sources was similar, showing approximately 70%. the PGCs enrichment method was improved using Ficoll density gradient centrifugation. After this step the purity of PGCs from germinal crescent, blood, and gonad was 45$\pm$9.10%, 85$\pm$1.18%, and 86$\pm$0.19%, respectively. Also, PGCs were picked up by mouth pipette to improve the purity. This improved method for the separation of PGCs from different sources will serve as a useful too to preserve the foundation stocks of poultry and to produce germline chimeras.

• Development and Reproduction
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• v.7 no.1
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• pp.15-22
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• 2003

The Fas antigen (Fas) as a cell-surface receptor protein which mediates apoptosis-inducing signals plays an important role in the immune system. Expression of Fas mRNA is detected not only in lymphoid organs but also in the nonlymphoid organs. In the ovary, most of the follicles is known to undergo atreisa through apoptosis. However, the exact mechanism of atresia was not elucidated yet. Therefore, the purposes of the present study were to investigate the expression of Fas and Fas ligand in mouse ovary and to clarify the relationship between expression of Fas and Fas ligand and atresia of follicle. The result of RT-PCR demonstrated that Fas and Fas ligand mRNA was expressed in ovary, especially granulosa cells and oocytes. The immunohistochemistry showed that the granulosa cells and oocytes in growing follicles were stained for Fas and Fas ligand, but primordial follicles were not. Furthermore, Fas and Fas ligand were intensively stained in the atretic follicles As results of TUNEL staining to detect apoptotic cells in the ovaries, the number of TUNEL-positive (apoptotic) granulosa cells and oocytes increased in the atretic follicles compared to the healthy normal follicles. These results demonstrate that there is the positive relationship between expression of Fas and Fas ligand in granulosa cells and oocyies and apoptosis of them leading to atresia of follicles. It suggests that expression of Fas and Fas ligand could be associated with atresia of follicles in mouse ovary.

• Korean Journal of Poultry Science
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• v.28 no.1
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• pp.69-76
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• 2001

Avian primordial germ cells (PGCs) originate from the epiblast and appear in the germinal crescent. These PGCs enter the developing blood vessels during stage 10∼12 (H&H), circulate in the blood stream, migrate into the developing gonadal anlage and differentiate into germ cells. However, it is not clear until when the migratory ability of PGC is maintained. This study was conducted to examine whether migratory ability is present in PGCs from the gonad at later embryonic developmental stages. In the present study, gonads were dissected from 5-, 6- and 10-day old quail embryos and treated with trypsin-EDTA. Gonadal PGCs (gPGCs) were purified by Ficoll-density-gradient-centrifugation and labeled with PKH26 fluorescent dye. The PKH26-labeled gPGCs were microinjected into the blood vessel of the recipient quail embryo. Manipulated recipients were incubated for 3 days, embedded in paraffin and sdctioned. The foreign gPGCs were detected by fluorescent and confocal laser microscopy. As a result, quail gPGCs, from 10, 6 and 5 day old embryos could migrate through the recipient blood stream at early stage and settle in the gonads. Thus, results suggest that gPGCs from upto 10-day old embryos keep properties seen in circulating PGC. Therefore, the PGCs of 10-day old embryonic gonads can be used for the tools of genetic manipulation.

• Journal of Radiation Protection and Research
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• v.32 no.4
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• pp.140-156
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• 2007

This research was performed to investigate the morphological changes of folliculus ovary according to the radiation dose. The whole body radiation of 200 cGy, 400 cGy, and 600 cGy was given to the each groups of 5 months-aged female mouse. Various staining methods used in this research are: Hematosylin-Eosin method, and immunohistochemistrical methods using BrdU, TUNEL, p53, p21, PCNA and inhibin. The minute structural changes of folliculus ovary were observed through an electron microscope with high magnification. The morphological changes of growing folliculus ovary became distinct as the dose of X-rays increased. Especially, the nuclei of granular cells showed manifest condensation and the changes of the transparent zone were distinct. As a result of histochemical reaction according to Masson's trichrome method and reticular fiber method, the changed granular cells, the deformed basilar membrane of folliculus ovary and the abnormal arrangement of the reticular fiber were observed. In the reaction of BrdU, the granular cells of normal folliculus ovary with positive reaction rapidly decreased according to the increase of the dose of X-rays. In TUNEL study, granular cells showing positive reaction in retarded folliculus ovary were expanded to growing folliculus ovary and primordial folliculus ovary according to the increase of the dose of X-rays. In case of 600 cGy of X-rays, oocyte underwent apoptosis. In p53 immunohistochemistry, p53 manifested to be stronger as the dose of X-rays increased. p53 reactivity was manifested distinctively in all cells comprising folliculus ovary following irradiation of 600 cGy. p21 was manifested in granular cells of folliculus ovary and showed very positive reaction around follicular antrum according to the increase of the dose of X-rays. In PCNA, positive reaction was manifested in growing folliculus ovary, mature folliculus ovary and primordial folliculus ovary, but the extent of the reaction decreased as the dose of the X-rays decreased. The finding that the reaction of granular cells around folliculus ovary was stronger than that near follicular membrane indicates that what was damaged first by X-ray was the cells near folliculus ovary and follicular antrum. The reactivity of $inhibin-{\alpha}$ showed difference according to the growing stage of folliculus ovary: $inhibin-{\alpha}$ showed the most strong reaction in mature folliculus ovary with follicular antrum. There was strong reaction in granular cells around follicular membrane but $inhibin-{\alpha}$ did not occur at all in theca cells comprising follicular membrane. $Inhibin-{\alpha}$ in ovary tissue exposed to 400 cGy of X-rays was manifested more strongly than in ovary tissue exposed to 600 cGy of X-rays, which was related to the phenomenon that granular cells of mature folliculus ovary underwent necrosis or apoptosis increasingly due to X-rays. In an electron microscope with high magnification, nuclei and protoplasm of granular cells in growing folliculus ovary abruptly underwent minute structural changes according to the increase of dose of X-rays. Cell residue, by-product of cell decease, neutrophil and macrophage around follicular antrum were observed. The minute structural changes in granular cells showed typical characteristics of apoptosis: the increase of electronic density due to nuclear condensation, fragmentation of nuclei and atrophy of protoplasm. Necrosis of cells was identified but it was not so remarkable. Macrophage with apoptotic bodies was scattered. Proportional to the radiation dose, we found that the generation of heterogeneous substance of normal ovary texture's follicular fluid, the emergence of dyeing characteristic in the basilar membrane of folicle, the generation of apoptosis, and the transformation of macrophages, etc. From this results, we can infer the possible radiation hazard on the ovary of cervix cancer patient with radiation therapy.

• Korean Journal of Ichthyology
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• v.33 no.1
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• pp.8-14
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• 2021

Spawning behavior of the endangered Korean fish, Microphysogobio koreensis, was investigated in the Seomjingang (river), Imsil-gun, South Korea, during the spawning season, April to May 2012. The mating system of M. koreensis, a broadcast spawner, was a primitive spawning mode, and involved one male and one female, unlike group spawning fishes. Spawning behavior of M. koreensis in the wild were observed in eight patterns as resting, male chase, body beating, parallel swim, female withdrawal, male competition, spawning and not guard while spawning behavior in the glass tank were verified in six patterns as resting, male chase, body beating, parallel swim, spawning and not guard. In particular, a behavioral attempt of the pre-spawning stage showed more frequently in the wild than in the glass tank. We assume that difference of spawning behavior might be implication on behavioral restrictions in small and narrow indoor glass tank.

• Korean Journal of Poultry Science
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• v.16 no.1
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• pp.1-8
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• 1989

This experiment was conducted to improve the performance of chickens by the precise separation and analysis of chromosomes which are integrated genetic materials, and by the use of gene manipulation techniques. Following are the main results obtained. 1. When the chromosomes were separated through the leucocyte culture and analyzed by Giemsa banding techniques (especially by the method in which 20 layers of banding patterns could be found in chromosome ＃1), the normal Patterns of chromosomes ＃l-9 and sex chromosomes, and the location of constitutive heterochromatin without any gene activities in all chromosomes were discovered. 2. To utilize the primodial germ cells (PGC) as the genetic vector which is one of the most important gene manipulation techniques, PGC's from triploid were transplanted to normal host embryos. Since the donor PGC's(3n) were found in the gonads of growing host embryos gene manipulation in poultry using PGC's, seemed to be possible.

• Development and Reproduction
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• v.13 no.2
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• pp.115-122
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• 2009

Spermatogenesis and ultrastructural characteristics of sperm of brackish water diploid Corbicula japonica were investigated by electron microscope observations. Based on the cytological studies, the spermatozoon of this species (brackish water diploid) C japonica is approximately 55 ${\mu}m$ in length. The sperm head (about 12 ${\mu}m$ long) is elongated and tapers with a slight curve. Sperm nucleus is about 7.90 ${\mu}m$ long, and the acrosome is about 2.70 ${\mu}m$ long: The morphologies of the sperm nucleus type and the acrosome shape of this species are a long arrow-like type and long cone-like shape, respectively. The sperm head of this species (external fertilization, dioecious and oviparous species) is partially modified from that of the primitive type, as seen in triploid Corbicula species (internal fertilization, hermaphrodite and ovoviparous species), reported by some authors. However, this species produces uniflagellate spermatozoa, unlike freshwater triploid hermaphroditic clams being possessed of partially modified biflagellate spermatozoa. Diploid C japonica is similar to those of other bivalves being possessed of a short midpiece containing four mitochondria surrounding the centrioles. 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, and from uniflagellate sperm cross sectioned, in particular, wing-like axonernal lateral fins are observed, as seen in external fertilization fishes.

• Development and Reproduction
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• v.5 no.1
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• pp.39-45
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• 2001

Black rockfish Sebastes schlegeli is one of scopaenid fish giving birth to yolk-sac larvae and distributed around the coast of Korea and Japan, and is one of main species which is cultured in Korea. The difffrentiation of thyroid gland and the changes of thyroid hormones (THs) concentrations in the whole body during early development of this species were examined and the relationship between thyroid gland and their growth will be presented. Total length (TL) and body weight (BW) of the larva at the parturition were 6.3${\pm}$0.1 mm and 3.6${\pm}$0.1 mg, respectively. The larvae transformed to juvenile after 30th day after parturition. According to Hoshiai(1977), they had gown into stage Fl (TL 13.2${\pm}$0.9 mm, BW 46.5${\pm}$1.5 mg) at 50th day. The thyroid gland of black rockfish was first observed histologically in hatching larvae in mother fish. The larvae just after parturition have 1${\sim}$3 of the thyroid follicles diffrentiated between basibranchial bone and ventral aorta, at the base of the first gill arch. In this time, thyroid follic1e number (TFN),thyroid follicle diameter (TFD) and thyroid cell height (TCH) were 1.6${\pm}$0.8 pieces/inds., 18.1${\pm}$0.6 ${\mu}$m and 4.1${\pm}$0.2 ${\mu}$m, respectively. TFN and TFD at 50th day were increased to 32.5${\pm}$6.9 pieces/inds. and 41.5${\pm}$1.7 ${\mu}$m, respectively. These results indicate that they are related to the growth of black rockfish during early development. However, TCH indicates that the activity of thyroid gland appearedat special day, eg. 5, 20 and 50th day, suggesting that TCH may have some role in the physiological activity. L-thyroxine (T$_4$)concentration decreased sharply to 10 days after parturition, and at 25th day (metamorphosis stage) increased markedly to 3.44${\pm}$0.93ng/g fish. After this time, T$_4$ concentration decreased at 35th day, but then increasedagain to the highest concentration, 5.63${\pm}$0.70ng/g fish. 3,5,3'-triiodo-L-thyronine (T$_3$) concentration declined sharply from just after pafurition (4.96${\pm}$1.90 ng/g fish) to 5th day (0.30${\pm}$0.07 ng/g fish). However T$_3$ concentration increased markedly to 0.95${\pm}$0.11 ng/g fish at 30th day and then did not significantly change until 45th day, increased also sharply to 1.67${\pm}$0.23 ng/g fish at 50th day.