[국내논문]Ultrastructures of Oocyte Development and Electrophoretic Patterns of the Yolk Protein Following HCG Treatment in Korean Native Catfish (Silurus asotus)원문보기
Yoon, J.M.
(Department of Marine Biomedical Science, Kunsan National University)
,
Chung, E.Y.
(Department of Marine Life Development, Kunsan National University)
,
Kim, G.W.
(Department of Animal Science, Kongju National University)
During the rapid phase of gonadal development of the freshwater teleost, the catfish (Silurus asotus), the influence of hCG upon the inducement of final oocyte maturation and spawning was investigated electrophoretically and ultrastructurally. The electrophoretic patterns obtained were different in ...
During the rapid phase of gonadal development of the freshwater teleost, the catfish (Silurus asotus), the influence of hCG upon the inducement of final oocyte maturation and spawning was investigated electrophoretically and ultrastructurally. The electrophoretic patterns obtained were different in the presence and absence of some of the major or minor zones, because of the hormone level in catfish. The vitellogenin of hormone-treated fish was stained more intensively than that of sham-treated fish. These proteins showed some minor or main bands of egg extracts which migrated at positions corresponding to molecular weights of approximately 90,000. However, the thickness of electrophoretic band in molecular weight for hCG-treated fish was slightly lower than that for saline control. It seemed the plasma protein with molecular weight of approximately 45,000 in hCG-treated fish disappeared. In contrast to the control fish, the ovaries in the catfish treated with hCG shows a marked ultrastructural change under the electron microscope. No dilated profiles were seen in the granulosa cells of the mature oocyte before ovulation. After germinal vesicle breakdown (GVBD), the zona radiata interna (ZRI) becomes more compact, and there is a loss of all the processes from the pore canals. There is a wide space between the vitelline membrane and zona radiata. Also, during final maturation, the microvillar processes from the oocyte are seen no longer to penetrate deeply into the extracellular spaces of the overlying granulosa cells, and the reticulate patterns of the zona radiata interna becomes occluded, giving the zona radiata a more solid appearance. It has been possible to initiate 100% oocyte maturation in yolk granules and follicles in vivo by treatment with hCG and a high water temperature ($27^{\circ}C$). In hCG-treated fish, the percentages of successful artificial fertilization and hatching were maximal at 15 h after a single injection. It seems clear that a long acting preparation containing hCG can be successfully used in prespawning fish to advance the final events of gonadal maturation and initiate spawning. Further studies are necessary to evaluate the potential of hCG to either stimulate or inhibit the reproductive development of fish at other stages of the seasonal reproductive cycle.
During the rapid phase of gonadal development of the freshwater teleost, the catfish (Silurus asotus), the influence of hCG upon the inducement of final oocyte maturation and spawning was investigated electrophoretically and ultrastructurally. The electrophoretic patterns obtained were different in the presence and absence of some of the major or minor zones, because of the hormone level in catfish. The vitellogenin of hormone-treated fish was stained more intensively than that of sham-treated fish. These proteins showed some minor or main bands of egg extracts which migrated at positions corresponding to molecular weights of approximately 90,000. However, the thickness of electrophoretic band in molecular weight for hCG-treated fish was slightly lower than that for saline control. It seemed the plasma protein with molecular weight of approximately 45,000 in hCG-treated fish disappeared. In contrast to the control fish, the ovaries in the catfish treated with hCG shows a marked ultrastructural change under the electron microscope. No dilated profiles were seen in the granulosa cells of the mature oocyte before ovulation. After germinal vesicle breakdown (GVBD), the zona radiata interna (ZRI) becomes more compact, and there is a loss of all the processes from the pore canals. There is a wide space between the vitelline membrane and zona radiata. Also, during final maturation, the microvillar processes from the oocyte are seen no longer to penetrate deeply into the extracellular spaces of the overlying granulosa cells, and the reticulate patterns of the zona radiata interna becomes occluded, giving the zona radiata a more solid appearance. It has been possible to initiate 100% oocyte maturation in yolk granules and follicles in vivo by treatment with hCG and a high water temperature ($27^{\circ}C$). In hCG-treated fish, the percentages of successful artificial fertilization and hatching were maximal at 15 h after a single injection. It seems clear that a long acting preparation containing hCG can be successfully used in prespawning fish to advance the final events of gonadal maturation and initiate spawning. Further studies are necessary to evaluate the potential of hCG to either stimulate or inhibit the reproductive development of fish at other stages of the seasonal reproductive cycle.
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가설 설정
Figure 5. A. Many yolk granules are located in the ooplasm of the spawned oocyte of hormone-treated catfish. B.
Many yolk granules are located in the ooplasm of the spawned oocyte of hormone-treated catfish. B. Part of the distinct banding of the zona radiata in a mature oocyte. Scale bar represents 2 μm
제안 방법
The various oocytes were observed on the optical microscope (Olympus, Japan). The changes in gonadosomatic index (GSI, gonad weight, g x 100/body weight, g) and hepatosomatic index (HSI, liver weight, g x 100/body weight, g) were employed to monitor gonadal maturation.
The GSI values employed in this study proved to be useful and sensitive parameters to monitor gonad maturation. These results were similar to the results of Lambert et al.
대상 데이터
Catfish eggs were obtained from the Department of Aquaculture in Kunsan National University. Samples were prepared from individual eggs obtained from the four seasons.
The authors are grateful to the Fisheries Science Institute of Kunsan National University for equipment and funding in the program year from 2000 to 2001.
The fish weighing from the 100 to 300g were reared in a freshwater pond (26 + 1℃). The fish were anaesthetized with MS 222 (1/10,000) and were injected intraperitoneally with 5,000 lU/kg human chorionic gonadotropin (hCG, Yuhan Cor, Korea) or 0.8% saline. Blood samples of fish before and after injection were taken from the caudal vein into heparinized vials.
1 M phosphate-sucrose buffer, post-fixed in 2% osmium tetroxide, dehydrated by graded series of ethanol and isoamyl acetate. The samples were critical-point dried with CO2 in a Balzers CPD 030, coated with 25 nm gold-palladium in a ion coater (Hitachi, Japan). The observations were made using a scanning electron microscope (Hitachi, Japan) operated at 20 kV.
성능/효과
, 1988). The number of mature oocytes as well as the GSI showed a distinct increase while the number of early perinucleolus, late perinucleolus and early maturing oocytes decreased.
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