• 대한생식의학회:학술대회논문집
• /
• 1994.10a
• /
• pp.26.2-27
• /
• 1994

• Korean Journal of Poultry Science
• /
• v.37 no.2
• /
• pp.139-143
• /
• 2010

Quail is a very useful animal model for studying vertebrate development because of its small body size and unique reproductive traits. This species is also ideal model for producing germline chimeras via transferring exogenous primordial germ cells (PGCs) into the recipient embryo. To increase the contribution efficiency of donor PGCs into recipients' tissues, decreasing the population of endogenous PGCs has been rate-limiting factor. We therefore conducted this study to investigate if gamma ($\gamma$)-irradiation depletes endogenous PGCs in developing quail embryo. Firstly, freshly laid stage X quail embryos were irradiated with various output of $\gamma$-irradiation and its teratogenic effect on the embryo was evaluated. Although a dose-dependent increase in the number of embryo showing malformation was found as the output increased (0, 250, 500, 750, and 1,000 rads), only a maximum of 10.1% of embryos were abnormal in 1,000 rads. Immunocytochemical analysis using the QCR1 antibody, which is specific marker for quail PGCs, was conducted to analyze the effect of sterilization. As results, $\gamma$-rays at a dose-rate of 500 rads/73 sec onto undeveloped stage X embryo significantly reduced the number of germ cells to an average of 75.55 % and 82.03 % in male and female embryos, respectively. We conclude that $\gamma$-ray selectively targets PGCs while affects minimally to the somatic development in quail embryo. Our results will not only provide important data for germline chimera production but can be used for analyzing the effect of ionized rays on the differentiating germ cells in various stages during animal development.

• Development and Reproduction
• /
• v.4 no.2
• /
• pp.195-201
• /
• 2000

Sex differentiation process of the spotted sea bass, Lateolabrax maculatus, was investigated by histological method. The fish samples were collected from just after hatching to 365 days later. The primordial germ cells and genital ridge were appeared separately hanging under air bladder in 30-day larva (total length: 11.7~13.2 mm), and were unified into the undifferentiated gonads in 40-day larva (12.5~14.0 mm). The ovarian differentiation was started in 60-day juvenile (23.6~27.0 mm). The somatic tissues were elongated in tip of both ends of undifferentiated gonad and were fused each other. The complete ovarian cavity was appeared in 80-days juvenile(33.1~42.5 mm). The testicular differentiation was initiated in 70-day juvenile (24.8~31.6 mm). The rudiment of sperm duct was appeared in the center of the undifferentiated gonad. The meiosis of germ cells in the ovary was started in 168-day juvenile (88.0~115.4 mm). In 287-day juvenile (175.1~233.6 mm), the ovary was filled with both of chromatin stage and perinucleolus stage oocytes. The meiosis of male germ cells was started in 245-day juvenile (124.4~168.3 mm). However, the seminiferous tubules of testis were filled with numerous sperm in 365-day juvenile (162.5~253.8 mm). The sex ratio of male and female was 1:1.38. Considering these results, the spotted sea bass was showed differentiated type in sex differentiation and gonochorism in sexuality.

• Applied Microscopy
• /
• v.31 no.2
• /
• pp.157-165
• /
• 2001

Sertoli cells in the normal adult testis are nondividing cells, which are relatively inconspicuous on cross section of the seminiferous tubule and comprise about 10% to 15% of the tubular cellular elements. Ultrastructurally, Sertoli cells have characteristic nucleoli, plasma membrane, and cytoplasmic components. The plasma membrane has two types of intercellular junctions which are developed at puberty: junctions between adjacent Sertoli cells and Sertoli cell-germ ceil junction. However, the ultrastructural findings of Sertoli cells in human fetus is not fully elucidate yet. In the present study, human fetal testes ($14\sim27$ weeks) obtained from artificially induced abortions legally without gross malformation were studied using transmission electron microscopy to make clear the differentiation process of Sertoli cells in human. In human fetal testes from 14 weeks to 27 weeks, the cell junctions of Sertoli-germ cells and Sertoli-Sertoli cells are desmosome like structure and not tight junction or desmosome. The Overall intracytoplasmic organelles of Sertoli cells are relatively sparse. The mitochondrias are relatively abundant but no developed cristae. And the rough endoplasmic reticuli are abundant and smooth endoplasmic reticuli are sparse. The amount of lipid droplets are regularly observed in human fetal Sertoli cells. No microfilaments or Charcot-Bottcher's crystalloids are present. From the results, Sertoli cells in human fetal testes are somewhat different ultrastructural findings with puberty or adult. However, to make clear the differentiation process of Sertoli cells in human, further study for 28 weeks to puberty is required.

• Korean Journal of Ichthyology
• /
• v.6 no.2
• /
• pp.237-243
• /
• 1994

This work was conducted to study sex differentiation in the black sea bream, Acanthopagrus schlegeli (Bleeker), using a histological method for the appearance of primordial germ cell, formation of primitive gonads, differentiation of female and male from newly hatched larva to the ovotestis stage of fish. The 3~4 primordial germ cells of $6.8{\sim}7.2\;{\mu}m$ in size, which were buried under fibrous mesenchymal tissue between gut duct and notochord of pre-larva with a total length (T.L.) of 2.4 mm at 3 days after hatching. The proto-gonial cells were located in the epithelium of the coelom attached with pigment cells of juvenile with 6.4 mm in T.L. at 21 days after hatching. In juvenile of 20.8 mm in T.L. at 59 days after hatching, the proto-gonial cells were migrated to the retro-peritoneum through the lineshaped primitive gonad composed of fibrous mesenchymal tissue. In juvenile of 7.8 em in T.L. at 186 days after hatching, the mitotic division of proto-gonial cell appeared in the lineshaped primitive gonad having many eosinophilic granule cells and abundant fibrous connective tissue. In juvenile of 9.5 em in T.L. at 254 days after hatching, the gonad was occupied by abundant fibrous connective tissue, bundles of spermatocyte and spermatid. In juvenile of 10.5 cm in T.L. at 13 months after hatching, the gonad was divided into cortical layer and medullary layer. The former was composed of bundles of a few spermatocytes and proto-gonial cells, the latter was filled with the fibrous mesenchymal tissue and a few proto-gonial cells. In juvenile of 14.7 em in T.L. at 16 months after hatching, the gonad was separated into ovarian part and testicular part by the fibrous connective tissue. The ovarian part is consisted of ovarian cavity and oocytes of perinucleolus stage. The testicular part was occupied by spermatogonia in the cyst.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.18 no.3
• /
• pp.253-261
• /
• 1985

The reproduction of marbled sole Limanda yokohamae, caught near around the southeastern coast of Korea, from December 1983 to November 1984, was investigated based on such annual variations as gonadosomatic index(GSL), gametogenesis, reproductive cycle, spawning number, hepatosomatic index (HSI), and fatness. GSI began to increase in the autumn season with the onset of shorter day length and colder water temperature, and reached the maximum value in December with the shortest day length and the lowest temperature over the year. The gonad activated the proliferation of oogonia and spermatogonia in June, reached the mature stage in October, ripe in December, and spawning from the end of December to January. After spawning, it showed the resting stage which gonad remained regressive and suppressive from February to May. In addition, the adult individuals observed discharged eggs only once during their spawning period. At yolk globular stage, the substance of vitellogenin synthesized from the liver was considered to participate in the active yolk accumulation of oocytes. Marbled sole was concluded to be a typical winter spawning species in that such environmental factors as short day length and low water temperature were closely related with the gametogenesis, the stimulation of oocyte maturation, and were also affecting the ovulation.

• Journal of Aquaculture
• /
• v.19 no.3
• /
• pp.188-196
• /
• 2006

Annual reproductive cycle of small yellow croaker, Larimichthys polyactis were histologically investigated based on samples captured nearby the coast around Chujado, Youngkwang and Kanghwa, South Korea from February $2004{\sim}February$,2005. By histological survey, the annual reproductive cycle was classified into the following successive stages: The primary growth stage from September to October, the second growth stage from October to December, the mature stage from January to April, the final mature, ovulation and spawning stage from May to June, the degeneration stage from June to July and the rest stage from August to September. Throughout anatomical observation of the ovary, it is found that the small yellow croaker, L. polyactis belongs to an asynchronous and multiple spawner from late spring to early summer.

• Proceedings of the Korea Society of Poultry Science Conference
• /
• 2006.11a
• /
• pp.82-83
• /
• 2006

생식 세포는 한 세대의 유전 정보를 다음세대에 전달할 수 있는 유일한 세포로서 다양한 특성을 가지고 있다. 기능 유전체 연구를 통해서 새로운 유전자의 기능을 규명함으로써 그 유전자의 생물학적 의미와 상호작용을 설명할 수 있다. 본 실험의 목적은 생식세포에서 특이적으로 발현하는 유전자를 발굴하여 그 유전자가 생식세포의 발달과 분화에 중요한 역할을 수행하는 것을 증명하는 것이다. 이에 본 실험에서는 real-time quantitative RT-PCR 기법을 이용하여 정소에서 특이적으로 발현하는 5개(AGE1, AGE2, AGE3, AGE4, AGE5)를 선발하였고, in situ hybridization 실험을 통하여 정소 조직 내에서의 발현 양상을 확인하였다. AGE1, AGE2는 round spermatid에서 특이적으로 발현하고, AGE3, AGE4, AGE5는 spermatocyte에서 특이적으로 발현하는 것을 확인하였다. 본 실험을 통해 발굴한 유전자들은 닭의 생식선발달에 중요한 기능을 할 것으로 예상되며, 앞으로 닭의 유전육종분야에 큰 도움을 줄 수 있을 것이다.

• Korean Journal of Ichthyology
• /
• v.13 no.4
• /
• pp.248-253
• /
• 2001

An histological study was conducted to determine the initial treatment time and treatment duration in the use of sex-reversal hormones in relation to gonadal development and sexual differentiation in the bagrid catfish, Leiocassis ussuriensis. The primordial germ cell, which could be recognized from one-day-old fry, began to protrude into the peritoneal cavity between the mesonephric duct and the gut. The primordial gonad with a genital ridge was developed at 5~10 days after hatching. Sex differentiation of the ovary was identified by the ovarian cavity and meiotic oocytes from 20-day-old larvae. Testicular differentiation was also identified by spermatogonial cells from 20-day-old larvae. It may therefore be concluded that this species belongs to the differentiated type of gonochoristic teleost.

• Proceedings of the Korean Society of Developmental Biology Conference
• /
• 2001.10a
• /
• pp.11-13
• /
• 2001