• 한국양식학회지
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• 제16권4호
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• pp.240-244
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• 2003

양식산 넙치를 대상으로 아치사 만성농도의 PCBs가 자어기의 원시생식소와 신장의 발달에 미치는 영향을 살펴보았다. 원시생식소 발달 과정은 4단계; 원시생식세포(primodial germ cell, PGC) 단계, 생식융기 (genital ridge type, GRT) 단계, 원시생식소 I형(primitive gonad type I, PGT I) 단계 및 원시생식소 II형(primitive gonad type II, PGT II) 단계로 구분할 수 있었다. 시원생식세포는 부화 후 3일에 발견되었고, 원시 생식소는 대조구에서 부화 후 24일에 나타나며 처리구에서는 부화 후 22일에 나타났다. 신장 발달과정은 4단계; 단일관형 중신관(unitubular type of mesonephric duct, UTMD) 단계, 분지형 중신관(the branched mesonephric duct, BMD) 단계, 세뇨관 형성(convoluted tubule formation CTF) 단계 및 사구체 출현(glomerulus appearance, GA) 단계로 구분할 수 있었으며, 신장의 구조적 완성시기는 대조구와 처리구 모두 부화 후 25∼30일로 나타났다. 하지만 원시 생식소와 신장 모두 대조구와 처리구에서 유의한 차를 보이지 않았다 (P>0.05). 그러므로, 넙치 자어기의 원시 생식소와 신장의 발달에 따른 PCBs(3.0 $\mu\textrm{g}$/L)의 영향은 없었다.

• 한국수산과학회지
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• 제39권5호
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• pp.398-403
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• 2006

Gonad development and the gametogenic cycle of pen shells, Atrina pectinata, collected from November 2004 to October 2005 in the coastal waters of Jangheung, Jeollanam-do, Korea were investigated histologically. The clams are dioecious. The gonads consist of a number of gametogenic follicles. The sex ratio (Female:male) was 1:1.2. The gonad index (GI) reached a maximum in May and a minimum in July. The condition index (CI) reached a maximum in April and a minimum in June. The gonadosomatic index (GSI), GI and CI all increased with gonad development. The gametogenic cycle of the clam could be divided into five stages: the degenerative/inactive (August to October), early active (November to March), late active (December to April), ripe (May to June) and spent (June to July) stage.

• 한국발생생물학회지:발생과생식
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• 제25권4호
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• pp.299-303
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• 2021

The ascidian Halocynthia aurantium (sea peach), a marine invertebrate, belongs to the same genus of the phylum Chordata along with the ascidian Halocynthia roretzi (sea pineapple), which is one of the model animals in the field of developmental biology. The characteristics of development and reproduction of H. aurantium are not yet known in detail. In order to find out the spawning period of H. aurantium, we investigated development of the gonads during the annual reproductive cycle. Testis and ovary were both in the bisexual gonads (ovotestes) of H. aurantium, which is a hermaphrodite like H. roretzi. In H. aurantium, the right gonad was longer and slightly larger than the left gonad throughout the year. In each gonad, the number of the testis gonoducts was slightly higher than that of the ovary gonoducts. These features were similarly observed in H. roretzi. However, the number of the testis gonoducts and the ovary gonoducts in each gonad of H. aurantium was about half that of H. roretzi. The gonads of H. aurantium contracted during the winter and summer seasons. The gonads decreased to the smallest size around February, and then started to increase again in March. The gonads were most developed in September of the year. Therefore, it is estimated that the spawning of H. aurantium begins around this period.

• Animal cells and systems
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• 제5권1호
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• pp.37-44
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• 2001

Gonadal development, reproductive cycle, gonad index, meat weight rate, and first sexual maturity of the top shell, Omphalius rusticus were Investigated monthly by histological observations. Specimens were collected from the west coast of Korea during the period from January to December in 1999. O. rusticus is dioecious and oviparous. The gonad is widely situated on the surface of the digestive g1and located in the posterior spiral meat part in the shell. The ovary and the testis were composed of a number of oogenic follicles and several spermatogenic follicles, respectively. Ripe oocytes were approximately 120-130 $\mu$m in diameter. The meat weight rate peaked in June (27.7%), and then rapidly decreased in September (19.5%). Monthly changes in the gonad index in both sexes reached the maximum in June, and then sharply decreased in September. Percentages of first sexual maturity of female and male snails ranging from 9.0 to 9.9 mm in shell heights were 58.3% and 54.5%, respectively, and 100% in those over 11.0 mm in both sexes participated in reproduction. Reproductive cycle of this species can be categorized into five successive stages: in females, early active (October to April), late active (December to June), ripe (April to September), spawning (July to September) and recovery (September to January): in males, early active (November to March), late active (December to June), ripe (April to September), spawning (July to September) and recovery (September to December). Gonadal development, gametogenesis, reproductive cycle, and spawning were closely related to the seawater temperature.

• 한국발생생물학회지:발생과생식
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• 제27권4호
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• pp.221-226
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• 2023

A stem cell niche provides an environment that governs stem cell maintenance and division. Thus, the development of a proper niche is of prime importance to stem cell behaviors. Mechanisms of niche development are beginning to be revealed in the Drosophila male gonad. Niche cells are initially dispersed throughout the gonad, then assemble at its apical tip through the anterior migration of posteriorly located niche cells. The molecular mechanisms of this migration and assembly are still poorly understood. Here we show evidence suggesting that Lin28, an RNA-binding protein and regulator of let7 genesis, might be an intrinsic factor for the anterior migration of niche cells. We found that a dispersed, ectopic niche, a phenotype observed with anterior migration defects, occurs in lin28 mutant gonads. This phenotype is rescued by expression of lin28 in the niche cells. These findings suggest that Lin28 might be required for the anterior migration of niche cells.

• 한국발생생물학회지:발생과생식
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• 제25권3호
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• pp.173-183
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• 2021

The incidence of infertility among individuals of reproductive age has been growing due to genetic and environmental factors, and considerable research efforts are focused on solving this issue. Ovarian development is an overly complex process in the body, involving the interaction between primordial germ cells and gonad somatic cells. However, follicles located in the center of the in vitro ovary are poorly formed owing to ovarian complexity, nutrient deficiency, and signaling deficiency. In the present study, we optimized methods for dissociating gonads and culture conditions for the in vitro generation of miniaturized ovaries. The gonads from embryos were dissociated into cell masses and cultured on a Transwell-COL membrane for 3-5 weeks. Approximately 12 follicles were present per in vitro ovary. We observed that miniaturized ovaries successfully matured to MII oocytes in vitro from 150 to 100 ㎛ gonad masses. This method will be useful for investigating follicle development and oocyte production.

• 한국수산과학회지
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• 제8권4호
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• pp.234-241
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• 1975

여수근해산 한전복 Haliotis discus hannai를 재료로 1973년 1월-12월까지 매월 1회씩 24회에 걸쳐 생식선열도지수, 성열도계수, 비만도등의 월변화와 각장 및 전중량의 생식선중량과의 관계, 수온조건 및 자연산모패의 산란유발 결과를 요약하면 다음과 같다. 1. 여수근해산 한전복의 산란가능기간은 5월 하순-7월하순과 9월상순-11월하순이며, 주요산란기는 5월하순-6월중순과 9월하순-11월하순으로 각각 추정되었다. 2. 생식선성열도계수가 극대치를 보인 것은 5월의 44.10과 9월의 49.05였고, 최소치는 1월의 10.09였다. 3. 비만도는 년중 7월이 0.221로 가장 높았으며, 10월에 0.1058로 가장 낮았다. 4. 각장(SL)에 대한 생식선중량(GW)의 비가 년중 가장 높았던 달은 9월이었고, 가장 낮았던 달은 1월로서 이때의 관계식은 9월 : $GW=0.0000003710SL^{3.7860}$ 1월 : $GW=0.000021198SL^{2.8564}$ 각년평균치 : $GW=0.0000005013SL^{4.2273}$ 으로 각각 표시되었다. 5. 전중량(TW)에 대한 생식선중량(GW)의 비가 년중 가장 높았던 달은 9월이었고, 가장 낮았던 달은 1월로서 이때의 관계식은 9 月 : GW=0.1918TW-4.9231 1 月 : GW=0.0992TW-0.1759 주년평균수 : GW=0.1568TW-3.5236으로 표시되었다.

• 한국발생생물학회지:발생과생식
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• 제24권3호
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• pp.225-230
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• 2020

This study reports the presence of mature and bi-sexual phase gonads in red spotted grouper, Epinephelus akaara after less than a year of cultivation in a commercial indoor tank and a net cage. In December 2018, juveniles were placed in an indoor tank and cultured for five months. In June 2019, the fish were transferred to a net cage and cultured until September. The rearing temperatures ranged from 19.86℃-24.65℃ in the indoor tank and 21.86℃-27.65℃ in the net cage. During the net cage culture period, specimens were randomly selected for histological gonad examination. The highest gonadosomatic index (GSI) value was measured in July (3.38±2.53), and dramatically decreased in August (0.44±0.21) and September (0.42±0.30). In July, some mature fish showed signs of vitellogenic stage oocyte development (vitellogenic and oil droplet stage oocytes), but immature fish were in an early developmental stage containing peri-nucleolus stage (PNS) oocytes. Bi-sexual phase gonads containing spermatocytes and spermatids were observed in the lumen and several PNS oocytes. By August and September, most specimens showed early-stage ovary development. However, mature testis (in August) and bi-sexual phase gonads (in September) were also observed. These results provide evidence for early puberty and hermaphroditism in the red spotted grouper.

• Fisheries and Aquatic Sciences
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• 제19권1호
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• pp.5.1-5.7
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• 2016

The study was conducted to know the cyclic changes in gonadal maturation and to investigate the developmental stages of oocytes and testicular germ cells of an air-breathing fish, Channa striata. Fish were sampled monthly from lentic and lotic environments of three geographical locations of Bangladesh from December to November and the histological analysis of their gonad was done to evaluate the objectives. The highest mean GSI was $5.95{\pm}0.20$ for female in July and $0.14{\pm}0.01$ for male also in July showing that the gonadal development reached its peak during this month. The highest mean oocyte diameter was $1257.50{\pm}24.17{\mu}m$ observed in July implying that the oocyte reached maturity in this month. Histological study of ovary revealed the evidence of early yolk granule stage and late yolk granule stage from April to July. In case of male four stages of spermatogenesis were distinguished and spermatozoa were highly abundant in June and July. So the monthly pooled values of GSI and the analysis of gonadal histology indicated that the peak breeding season of C. striata occurred in July in the lentic and lotic environments. Samples collected from lentic and lotic habitats are suggestive of no difference in the development of the gonad. The results of the present study will be useful for selective breeding programme, conservation and sustainable fishery management of C. striata in its natural habitat.

• 한국발생생물학회지:발생과생식
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• 제16권3호
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• pp.185-193
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• 2012

For the gonadal sex management of younger longtooth grouper (Epinephelus bruneus), this work investigated the timing and histological process of ovary differentiation and oocyte development of longtooth grouper larvae and juvenile. Specimens (from 1 to 365 DAH) were collected for gonadal histological study from June 2008 to August 2009. Rearing water temperature was ranged from 20 to $24^{\circ}C$. The primordial germ cells could be observed from 10 to 15 DAH, while undifferentiated gonad occurs from 20 to 50 DAH in longtooth grouper. The initial ovarian phase was 60 to 110 DAH with the formation of ovarian cavity and the increased in size of gonad. The ovarian phase started at 140 DAH with appearance of oogonia. The gonad at 365 DAH appeared to have full of oogonia and primary growth stage oocyte. Formation of ovarian cavity indicates that the ovarian differentiation beginning at 60 DAH in longtooth grouper. The gonads in longtooth grouper differentiated directly into ovaries in all fish examined.