• Title/Summary/Keyword: egg envelope

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The Oogenesis of Three Spot Gourami, Belontiidae, Teleostei (경골어류 등목어과 Three spot gourami의 난자형성과정)

  • Chang, Byung-Soo;Jung, Han-Suk;Joo, Kyung-Bok;Kim, Dong-Heui
    • Applied Microscopy
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    • v.41 no.3
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    • pp.155-161
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    • 2011

  • Three spot gourami (Trichogaster trichopterus Pallas, 1770) is a teleost belonging to Belontiidae. The oogenesis of three spot gourami was investigated by light microscope. The ovary was of light peach color 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 primary oocyte, lipid droplets were distributed only in the marginal area first, than at nuclear envelope near. In secondary oocyte, the egg envelope was formed and yolk vesicles was formed in the marginal area. 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 fertilized eggs were the colorless, transparent, spherical, adhesive and pelagic type. A large oil droplet was located in vitelline membrane of the fertilized egg. In conclusion, the oogenesis of three spot gourami was characterized by the increase in cell size, the formations of lipid droplets and yolk, the decrease of basophilic substance in the cytoplasm, and formation of one large oil droplets.

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Chemical Dissection of Zebrafish Egg Envelop, the Chorion

  • Hwang, C. N.;H. J. Kang;Kim, C.;D. S. Na;S. K. Chae;B. K. Joo;Lee, J. W.;Lee, S. H.
    • Proceedings of the KSAR Conference
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    • 2004.06a
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    • pp.283-283
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    • 2004

  • The eggs of most animal species are surrounded by an extracellular matrix known as chorion, egg envelope, egg coat, or zona pellucida. Development of fish embryo usually takes several days in an aquatic environment. During embryonic development, the chorion must protect embryo from physical damage and microbial infection in the exposed aquatic environment. (omitted)

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Attribution of Cortical Granules to Formation of Fertilization Envelopes and Polyspermy Block in Urechis unicinctus

  • Shin, Kil-Sang;Kwon, Hyuk-Jae;Kim, Wan-Jong
    • Animal cells and systems
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    • v.9 no.2
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    • pp.57-64
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    • 2005

  • Cortical reaction and polyspermy block are well defined in most marine invertebrates. In Urechis species, the function of cortical granules (CGs) is not yet known, and there is controversy on whether the cortical reaction occurs, or the fertilization envelope (FE) is attributed to CG releases or functions to prevent polyspermy. This study was carried out to determine the cortical reactions and functions of the FE in Urechis unicinctus. Artificial insemination of the eggs revealed that CG release occurred to give rise to perivitelline space (PS) into the final FE. Both PS and final FE effectively blocked polyspermy. The final FE was accomplished within 10 min after sperm-egg initial binding. No massive release of CGs occurred within the early phase of 5 min after the initial binding, initially and the PS seemed to playa role to prevent polyspermy. The CG massively released its content into the PS in late phase of FE formation, and differentiated PS into five intermediate layers. The layers opened into each other by anastomosis, so that the final FE consisted of two layers, the inner layer ($15{\mu}m$ in thickness) and the outer layer ($1{\mu}m$ in thickness). The outer layer derived from vitelline layer and the inner layer consisted of PS and CG secretions. Immunofluorescence and confocal laser microscopy revealed that the spermatozoon took up residence in the egg cortex during FE formation and successive meioses of the fertilized egg. These results suggest that both PS and final FE of U. unicinctus were equivalent to the early and late block, respectively, of other marine animals.

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Ultrastructural Changes in the Formation of Yolk Granules and Vitelline Envelope in Aedes togoi (토고숲 모기 (Aedes togoi)의 난황립 및 난황막 형성에 따른 미세구조적 변화)

  • Lee, Yang-Rim;Sol, Tae-Min
    • Applied Microscopy
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    • v.24 no.1
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    • pp.114-122
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    • 1994

  • Drastic changes were observed in egg chamber during oogenesis of Aedes togoi immediately after blood meal. The egg chamber, in which the oocyte remains at previtellogenic stage before blood meal, shows very little change in size even for 3 days after emergence but increased 25 folds in volume within 60 hours after blood meal, presumably due to rapid yolk formation. Upto 6 hours after blood meal structures considered to be the precursor of the yolk granules were not observed in the space between follicle cells and oocyte. Vitelline bodies, which are similar to dense bodies secreted from follicle cells, appeared in the space at 10 hours after blood meal. Although vitelline bodies were fused to form vitelline layer, these bodies seem to contribute to the formation of yolk granules. Nurse cells are connected to oocytes by cytoplasmic bridge before blood meal, but the cells are absorbed into oocyte at 6 hours after blood meal.

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