• Asian-Australasian Journal of Animal Sciences
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• 제17권4호
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• pp.453-459
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• 2004

Chick embryos from stage 14 to stage 31 were studied by means of serial section and light microscopy in order to learn the relationship between the settlement sites of the primordial germ cells (PGCs) and the forming genital ridge. The results showed that: when embryo hatched for 53-56 h, the PGCs reached the coelomic epithelial tissue where gonad would be formed, meanwhile the epithelial tissue began thicker before the PGCs reached. Before stage 19, the final region the PGCs arrived was the thickened portion of the coelomic epithelium, the glycogen in the PGCs cytoplasm maintenance remained unchanged. However at the 3.5-5th hatching day, the glycogen in the PGCs cytoplasm reduced gradually. On the 6th hatching day, the gonad of the embryo appeared the feature of ovary, and the glycogen in the PGCs cytoplasm reduced further. On the 7th hatching day, the differentiation of ovary or testis was obvious and the glycogen in the PGCs cytoplasm later disappeared.

• Fisheries and Aquatic Sciences
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• 제26권3호
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• pp.224-233
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• 2023

This research was conducted at Langgur City, Southeast Maluku Regency, Maluku Province, Eastern Indonesia from November 2020 to February 2021 to study biological aspects of roundscads (Decapterus spp.) which consist of species composition, sex ratio, gonad maturation level, size distribution, length-weight relationship and condition factor. Samples were collected at traditional fish market in Langgur City. Fish samples collected at the market were put into cool box and then brought to the laboratory for further examination. Fish samples were identified, separated based on species, dissected to determine their sex and gonad maturation stage and then measured. Totally, there were 290 specimen collected which consist of five species namely Decapterus kurroides, D. macarellus, D. macrosoma, D. muroadsi and D. russelli. Sex ratio between male and female for all species showed 1:1. Gonad maturation level showed that stage I and II have higher percentage than stage III and IV indicates immature fish more dominant compare to mature one. Among five species found, D. macarellus has larger size while the smaller belongs to D. muroadsi. Results of length-weight relationship analysis showed that roundscads inhabiting Southeast Maluku waters have isometric and negative allometric growth pattern with relative condition factor around 1.00.

• Fisheries and Aquatic Sciences
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• 제13권2호
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• pp.140-149
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• 2010

We determined the seasonal gonad maturation in Strongylocentrotus nudus sea urchins inhabiting an artificially enhanced seaweed forest along the Samchuk Coast of Korea from April 2006 to March 2007. A total of 30 sea urchins per month were collected from the study area, and gonadosomatic index (GSI), gonad index (GI), egg diameter, and RNA/DNA variation were measured for each specimen. GSI values of female and male urchins achieved maximums of 17.6 and 17.0, respectively, in June. Based on histological studies, maximum GI values occurred in July (4.6 for females and 4.8 for males). A mean ovarian egg diameter of $73.7\;\pm\;14.2\;{\mu}m$ was measured in August; during the main spawning period in September, mean egg diameter reached a maximum of $74.2\;\pm\;17.8\;{\mu}m$. The RNA/DNA ratio and RNA content for both males and females showed a distinct peak during the ripe stage in July, but another peak occurred in the spring season from March to April, when urchins deposit protein into the nutritive phagocytes of immature gonads prior to gametogenesis. The reproductive cycle of S. nudus is divided into five stages: early active (December-May), late active (March-July), ripe (July-September), spent and degenerative (August-November), and inactive (October-February). Our continuous removal of sea urchins from the study area did not influence the reproductive cycle, as populations quickly recovered, and achieved normal gonad development cycle in the site.

• 한국패류학회지
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• 제18권2호
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• pp.67-76
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• 2002

1997년 7월부터 1998년 6월까지 제주도 함덕리 조간대에서 매월 채집한 흑백배말 (Cellana nigrolineata) 의 생식세포형성과정, 생식주기, 월별 난경 조성 및 생식소지수를 조사하였다. 생식소는 내장낭 내면, 복부 앞쪽에 위치하며, 성숙시기에 정소는 유백색을 난소는 짙은 갈색을 띠고 있다. 생식소지수는 수온이 상승하는 5월부터 서서히 증가하기 시작하여 8월에 최고 값을 나타냈다. 이후 9월에 감소하기 시작하여 8월에 비교적 낮은 값을 유지하였다. 생식주기는 생식소의 월별변화와 난모세포의 크기에 따라 회복기 (11-4월), 활성기 (3-6월), 완숙기 (5-10월) 그리고 방출기 (8-12월)로 구분되었으며, 주 산란기는 9-10월로, 연 1회의 산란시기를 갖는다. 흑백배발은 자웅이체로서 성전환 개체나 자웅동체의 개체는 없었다.

• Environmental Analysis Health and Toxicology
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• 제14권1_2호
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• pp.55-63
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• 1999

Endocrine disrupting chemicals probably cause the cytological or/and morphological changes of germinal cells in gonad. Accordingly, this study was aimed to make sure that the effect of hormone-mimicking chemicals on gonad morphology such as decrease of germinal cells, inhibition of cellular maturation and change in the ratio of germinal cells in the different developmental phase can be observed by histopathological procedures and can be a useful bio-indicator for the evaluation of endocrine disruption by environmental chemicals. In this experiment, female Japanese medaka were exposured to quercetin, a phytoestrogen, at the concentration of 100 $\mu\textrm{g}$/L. quercetin showed the significant decrease in the number and rate of vitellogenic follicular oocytes in the treated group for 4 and 6 weeks. The weak development of yolk could be also observed. We could conclude that quercetin has anti-estrogenic or androgen-like potency by exerting the inhibition effect on oogenesis in fish female- gonad. From the result of this study, the applied methods and techniques can be evaluated to be a useful biomonitoring means for water pollution, expecting a good result of the subsequent study on apoptosis.

• 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.

• 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.

• 한국양식학회지
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• 제11권4호
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• pp.529-546
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• 1998

부화직후 1.9 mm였던 자어는 부화후 47일경 19 mm전후로 성장하며 초기성장기 자어류들의 전장과 체중과의 관계는 $BW=4.45{\times}10^{-6}TL^{3.4718}$, r=0.9820이었다. 해상가두리의 사육개체는 최대어 전장 28.4 cm까지 성장한 개체를 사용하였고 이들 개체의 전장과 체중과의 관계는 $BW=2.36{\times}10^{-2}TL^{2.9180}$, r=0.9971이었다. 미분화된 참돔의 생식소부위는 생식소와 지방체로 구성되어 있으며 분화가 진행되어 생식소가 비후됨에 따라 지방체는 점점 수축되어 갔다. 부화후 6개월의 미분화기까지 발달한 생식소부위는 생식소와 곤봉상의 지방체로 구성되었다. 이들 생식소는 미세한 반투명산으로 생식원세포를 구별할 수 없는 미발달생태를 유지하고 있다. 부화후 7개월부터 생식소 상피조직의 발달로 생식상피를 식별할 수 있었고, 부화후 8개월 생식소는 난원세포의 발달로 성분화가 시작되었다. 이후 9개월 생식소 내강상피 전체에 초기 난모세포들이 발달하고 이들 난모세포들의 증가로 생식소내강은 난소강을 이룬다. 부화후 13개월 난모세포는 생식소전체를 채우게 되고 곧 난모세포들의 세포질 붕괴가 시작된다. 15개월부터는 난소강을 중심으로 새로운 초기 난모세포들이 발달하여 난소조직으로 된다. 그리고 공포상조식은 정원세포들이 분열.증식하여 정소조직을 이루게 된다. 이후 이들은 생식소자웅동체기를 지나 암.수로 성이 결정된다. 따라서 참돔은 유시자웅동체 juvenile hermaphrodite 이고 미분화자웅이제 경골어류 undifferentiated gonochoristic teleost이었다. 생식소 자웅분화상은 미분화기, 유사난원세포기, 유사난소기, 난소발달기, 정소형자웅동체기, 난소형자웅동체기 및 정소발달기로 구분되었다. 미분화기 생식소는 부화후부터 13개월, 전장 18cm까지 지속되었으며, 유사난원세포기는 부화후 7~13개월, 전장 11~18cm까지 지속되었다. 유사난소기는 부화 10~14개월, 전장 14~26cm까지이며, 난소발달기는 부화후 14개월, 전장 20cm부터 시작되었다. 부화후 20개월에는 전 조사개체의 44%가 난소였다. 난소형자웅동체기는 부화후 15개월, 전장 19~20cm부터 출현하며, 부화후 20개월, 전장 28~29cm에서는 관찰되지 않았다. 정소형자웅동체는 부화후 15개월, 전장 21~22cm에서 첫 출현한 후 20개월까지 지속되었다. 정소발달기는 부화후 15개월, 전장 21~22cm에서 첫 출현한 후 20개월의 39%, 전장 28~29cm의 33%를 차지하였다. 50%이상의 성분화발현은 부화후 11개월, 전장 16cm부터였다. 성결정은 암컷이 부화후 14개월, 전장은 20mc, 수컷이 부화후 15개월, 전장 20cm에 시작되었다. 50%이상의 성결정은 부화후 17개월, 전장 23cm에 일어났다

• 한국수산과학회지
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• 제17권6호
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• pp.523-528
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• 1984

자연에서 5월중순부터 10월초기까지 산란기를 가지는 그물코쥐치, Rudarius ercodes를 대상으로 이들의 생식주기성립기구를 밝히고저 여러가지 광주기 및 온도 조건이 생식소의 활성과 퇴화 그리고 재성숙에 미치는 영향을 실험적으로 조사하였다. 이른봄에 생식소는 장일광주기(13L이상)에 의해서 활성화되어 산란기에 이르게 되며, 이때 수온상승이 보상적으로 촉진역할을 한다. 일단 임계일장($12L{\sim}13L$)이상이 작용되어 생식소 활성화가 일어난 개체들은 임계일장 이하에 되돌려도 생식소는 계속 성숙하였다. 산란종료기에는 수온에 관계없이 단일(12L)적으로 생식소 퇴화가 초래되고 있어 자연에서 일장단축이 산란기를 종료시키는 요인임을 알 수 있다. 산란기를 종결하고 퇴화중인 생식소에서도 $20^{\circ}C$ 수온의 장일광주기(13L이상)에서 재성숙하여 산란까지 이르고 있어 연중 생식주기의 인공적인 제어가 가능함을 시사하고 있다. 이때 장일광주기일지라도 $28^{\circ}C$이상의 고수온구는 성숙억제현상이 나타났다.

• 대한생식의학회:학술대회논문집
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• 대한불임학회 1995년도 춘계 학술대회 및 임시총회
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• pp.3-4
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• 1995