• The Korean Journal of Malacology
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• v.23 no.2
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• pp.209-216
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• 2007

The ovarian structure and ultrastructural changes in germ cells during oogenesis of the spiny top shell, Batillus cornutus, have been investigated by light and electron microscopic observations. Specimens of the spiny top shell were collected from the subtidal zone of Wando, south coast of Korea. Spiny top shell was dioecious. The ovary was located on the surface of the hepatopancreas in the spiral posterior region. The ovary had greenish color in the gonadal mature season. The ovary comprised many ovarian lobules, and the ovarian lobule consisted of connective mesenchymal tissue and epithelial cells. Oogonium had a large nucleus with nucleolus of high electron density. In previtellogenic oocyte, small yolk granules of low electron density were scattered in the cytoplasm. Oocytes in the initial vitellogenic stage were connected with the ovarian lobule by egg stalk. The result of TEM observations showed that initial vitellogenic oocyte contained well-developed Golgi complex, endoplasmic reticula, tubular mitochondria and numerous yolk granules of various electron densities and sizes. The electron density, size and quantity of yolk granules which were distributed in the active vitellogenic oocyte were increased compared to the previous stage. Thickness of egg envelope in the late active vitellogenic oocyte was approximately 4.4 $[\mu}m$. Cytoplasm of ripe oocyte was filled with proteid yolk globules of high electron density and lipid yolk globules of low electron density. In this stage, the thickness of egg envelope was approximately 6.5 ${\mu}m$.

• Applied Microscopy
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• v.41 no.3
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• pp.163-168
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• 2011

Tiger barb (Puntius tetrazona Bleeker, 1855) is a teleost belonging to Cyprinidae. The oogenesis of tiger barb was investigated by light microscope. The ovary was of white and ellipsoidal shape with the major axis 2 cm and the minor axis 1 cm. Cytoplasm of oogonia was basophilic and many nucleoli were located at inside of nuclear membrane. In early stage of primary oocyte, yolk vesicles were distributed only in the marginal area. In secondary oocyte, the egg envelope was formed and yolk vesicles was formed in the cytoplasm. The basophilic substance of cytoplasm was changed to acidic. In case of matured egg, thickness of egg envelope and size of egg were increased. The yolk vesicles were changed to yolk mass in accordance with development. Also, there is not the formation of oil droplets in cytoplasm. In conclusion, the oogenesis of tiger barb was characterized by the increase in cell size, the formation of yolk, the decrease of basophilic substance in the cytoplasm, and formation of yolk mass.

• The Korean Journal of Zoology
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• v.38 no.2
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• pp.145-152
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• 1995

노랑초파리의 난실에서의 단백질 합성을 난자형성과정의 단계별로 자기방사법을 이용하여 관찰하였다 단백질은 영양세포에서 난자형성 초기에 미약한 정도로 함성되는 것으로 나타나지만, 가장 활발하게 합성되는 세포는 여포세포이다. 난모세포와 영양세포에서는 단백질이 거의 합성되지 않고 있다. 여포세포에서 합성된 단백질은 Stage 10 이후의 단계에서만 난모세포로 이동하는 것으로 관찰되었다 난모세포에 괸만하게 분포된 은입자는 난자 형성을 위한 다양한 목적을 위해 여포세포로 부터 이입된 단백질로 짐작된다. 특히 난황립의 형성에 여포세포의 단백질이 최소한도 부분적으로 관여한다는 사실을 알 수 있었다.

• Applied Microscopy
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• v.38 no.4
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• pp.315-319
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• 2008

Glow-light tetra, Hemigrammus erythrozonus is a teleost belonging to Characidae. The natural habitate of this fish is the wild in the Essequibo river, Guyana and South America. The oogenesis of glow-light tetra was investigated by light microscopy to compare with those of other families. A pair of ovary was located between swim bladder and intestines. The ovary was of white color and ellipsoidal shape with the major axis 11 mm and the minor axis 4 mm. Cytoplasm of oogonia was basophilic and many nucleoli were located at inside of nuclear membrane. In primary oocytes, yolk vesicles were distributed only in the marginal area and egg envelope was not formed on the outside of an egg. In secondary oocytes, the egg envelope was formed and yolk vesicles in the cytoplasm were increased than the earlier stage. The amount of basophilic substance was decreased. In case of matured egg, thickness of egg envelope and size of egg were increased, basophilic substance was distributed in only around the egg envelope. The yolk vesicles were changed to yolk mass in accordance with development. In conclusion, the oogenesis of glow-light tetra, Hemigrammus erythrozonus was characterized by the increase in cell size, the formation and accumulation of yolk, and the decrease of basophilia a in the cytoplasm. The oogenesis of glow-light tetra seems to share common patterns in Characidae, teleost and have a similar pattern with other teleost.

• Applied Microscopy
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• v.30 no.4
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• pp.367-376
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• 2000

The observation using an electron microscope shows that the maturation of the oocyte of African giant snail, Achatina fulica, proceeds over three stages. The oocyte of stage 1 is a small elliptic cell $(220\times400{\mu}m)$ whose light nucleoplasm contains two nucleoli. In its cytoplasm, a number of mitochondria, rough endoplasmic reticula, and ribosomes are found, while yolk granules are not. The nucleus of the oocyte of stage 2 is relatively large in comparison with the volume of cytoplasm, and contains one nucleolus. In the nuclear envelope comprising inner and outer double membrane, there are found a lot of nuclear pores for materials to pass through. A number of mitochondria, Golgi complex and lipid yolk granules appears in the cytoplasm, and proteinous yolk granules begin to form and mature in the vacuoles of various sizes ($0.8\sim3.0{\mu}m$ in diameter). The oocyte of stage 3 has an enlarged nucleolus. Material transportation through nuclear pore is not found any longer. The cytoplasm in this stage is filled with proteinous and lipid yolk granules. The microvilli are developed around the egg plasma membrane.

• Applied Microscopy
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• v.39 no.3
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• pp.237-243
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• 2009

Chinese minnow, Rhynchocypris oxycephalus is a teleost belonging to Leuciscinae, Cyprinidae. The oogenesis and ultrastructure of egg envelope in Chinese minnow were investigated by light and electron microscopes. The ovary was of white yellowish and ellipsoidal shape with the major axis 30 mm and the minor axis 7mm. Cytoplasm of oogonia was basophilic and many nucleoli were located at inside of nuclear membrane. In primary oocytes, yolk vesicles were distributed only in the marginal area and egg envelope was not formed on the outside of an egg. In secondary oocytes, the egg envelope was formed and yolk vesicles in the cytoplasm were increased than the earlier stage. The basophilic substance of cytoplasm was changed to acidic. In case of matured egg, thickness of egg envelope and size of egg were increased. The yolk vesicles were changed to yolk mass in accordance with development. The outer surface of egg envelope was covered by microvilli-structures, and had a micropyle on the area of animal pole. Egg envelope consisted with 2 layers, an adhesive outer layer with microvilli-structures and fibrillar inner layer. In conclusion, the oogenesis of Chinese minnow was characterized by the increase in cell size, the formation and accumulation of yolk, and the decrease of basophilic substance in the cytoplasm. The oogenesis of Chinese minnow seems to share common patterns in Cyprinidae, but these ultrastructural unique characters of egg envelope can be utilized in taxonomy of teleost.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2001.02a
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• pp.71-73
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• 2001

밀어 (Rhinogobius brunneus)의 난자형성과정에서 난황전구 단백질 (vitellogenin, Vg)의 변화 및 estrogen에 의한 혈청단백질의 유도에 관하여 조사하였다. 혈청내 Vg는 분자량 190, 130 및 115 kDa(reduced form)으로 난자의 성숙과정에서 peptide cleavage가 일어났다. 수컷 밀어에 17$\beta$-estradiol을 1회 주사한 후 48시간에 다량의 Vg로 추정되는 단백질이 유도되어 1주간 지속되었으며 이후로 감소하였다. 이러한 현상은 동계적응 밀어에서는 관찰되지 않았다. 환경 estiogen의 일종인 nonylphenol을 주사하여 Vg으로 추측되는 혈청단백을 유도하였다. 밀어는 환경에스트로젠에 의한 수컷에서 Vg유도에 적합한 실험어류로 사료된다.

• Korean Journal of Environmental Biology
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• v.33 no.4
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• pp.419-424
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• 2015

In order to determine the ovarian cycle of Asian Toad, Bufo gargarizans, the developmental stage based on the gonadosomatic index (GSI), size of follicle oocytes in ovary and vitellogenesis for adult females were investigated all around the year. The weight of ovary and GSI were the lowest from April, and all follicle oocytes exist in the pre-vitellogenic form, indicating that the vitellogenesis was suspended. The follicle oocytes in early-vitellogenic stage appeared in ovary during may when the weight of ovary and GSI start to increased, and the follicle oocytes in mid-vitellogenic and pre-vitellogenic stages existed during June and the weight of ovary and GSI also increased. This indicates that vitellogenesis has been carried out actively during this period. The follicle oocytes in mid-vitellogenic stage and late-vitellogenic stage when the vitellogenesis was also completed existed on September. Post-vitellogenic follicle oocytes after vitellogenesis started to appear from October and rapidly increased from December in hibernation. The full grown follicle oocytes existed during February, indicating the ovarian cycle that all follicle oocytes in ovary are developed separately, not synchronized, during the growing period of follicle oocytes and the post-vitellogenic follicle oocytes are maintained the ovulation period.

• Korean Journal of Environment and Ecology
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• v.28 no.3
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• pp.287-292
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• 2014

In order to determine the ovarian cycle of Korean brown frog, Rana coreana, the developmental stage based on the gonadosomatic index (GSI), size of follicle oocytes in ovary and vitellogenesis for adult females were investigated all around the year. The weight of ovary and GSI were the lowest from March to May, and all follicle oocytes existed in the pre-vitellogenic form, indicating that the vitellogenesis was suspended. The follicle oocytes in early-vitellogenic stage appeared in ovary during June when the weight of ovary and GSI started to increase, and the follicle oocytes in mid-vitellogenic and pre-vitellogenic stages existed during August and the weight of ovary and GSI also increased. This indicates that vitellogenesis has been carried out actively during this period. The follicle oocytes in mid-vitellogenic stage and late-vitellogenic stage when the vitellogenesis was also completed existed between September and November. Post-vitellogenic follicle oocytes after vitellogenesis started to appear from December in hibernation, and the full grown follicle oocytes existed during February, indicating the ovarian cycle that all follicle oocytes in ovary are developed separately, not synchronized, during the growing period of follicle oocytes and the post-vitellogenic follicle oocytes are maintained the ovulation period.

• Applied Microscopy
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• v.41 no.3
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• pp.189-196
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• 2011

Histological study on egg envelope and oogenesis of Kichulchoia multifasciata (Pisces, Cobitidae) was carried out by light microscopes and scanning electron microscopes. Various developmental cells appeared in ovary of the specimen catched during November 2010. The cytoplasm of oogonia was acidic and many nucleoli were located at the inner side of nucleus membrane. The size of the oogonia was $103.9{\pm}24.7$ ${\mu}m$ with nucleus size $42.9{\pm}6.9$ (31.1~50.3) ${\mu}m$. Primary oocyte having $277.5{\pm}60.5$ (216.7~354.9) ${\mu}m$ in diameter began to accumulate yolk vesicles. As the developmental stages proceed, secondary oocyte grows larger to $617.6{\pm}85.1$ (503.4~723.6) ${\mu}m$, and eosinophilic yolk granules yolk granules appeared between the yolk vesicles occupying most cytoplasm, and there are some yolk mass formed already. There are some yolk mass formed already. Envelope of fertilized egg investigated by a scanning electron microscope had plenty of microvilli (2~3 ${\mu}m$ in length) over the entire egg surface and a micropyle. Especially, the microvilli surrounding the micropyle were longer than those of egg surface with $5.26{\pm}1.22$ ${\mu}m$.