• The Korean Journal of Zoology
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• v.31 no.4
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• pp.318-326
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• 1988

여포세포에서 합성된 난황단백질이 난모세포로 이동하는 동안에 난황체가 이 두 종류의 세포사이에 형성되었다가 결국은 난황막으로 전환한다. 단계7까지는 뚜렷하게 보이던 난모세포막과 여포세포막이 소멸되고 그 자리에 전자 밀도가 높은 난황체 물질이 산만하게 축적된다. 난황체는 단계9에서 막성 구조의 일종인 linkage bridge로 둘러싸여 단계11까지는 두께가 5∼7um가 되리 만큼 성숙한다. 단계13에서 난황체는 비로소 난황막으로 전환되는데, 이때 난황막의 두께는 겨우 1 U m에 지나지 않는다. 이러한 두깨의 감소는 난황체 물질이 다량 난모세포 쪽으로 이동한 것으로 생각 되었다. coated vesicle을 포함한 다양한 종류의 과립이 난황체 양쪽에서 관찰되었는데, 난모세포쪽에 출현한 과립은 난황체 물질이 난모세포로 이동되는 구조로 해석되었고 여포 세포쪽에서 관찰된 과립은 주로 난황체의 전자밀도와 동일한 점으로보아 여포세포에서 합성되어 난황체를 형성하는 물질로 이루어진 구조로 해석되었다. As yolk proteins are transported from !he follicle cells into oocvtes, vitelline body forms and changes into a vitelline membrane between the ko celt types during the vitellogenic period. Cell membranes of oocyte and follicle cells surrounding the oocyte disappear at stage 7 and high electron-dense substance of vitelline body simultaneously accumulates sporadically between the cell types. The vitelline body becomes surrounded by linkage bridge, a membranous structure, at stage 9 and greatly increases in thickness to be 5-7 U m thick at stage 11. At stage 13 the vitelline body becomes vitelline membrane, which is now only 1 U m thick, suggesting that much of the substance of the vitelline body has been transported into oocyte. Various types of vesicles including coated vesicles were observed at both sides of th vitelline body. The vesicles occurred at the side of oocyte were interpreted to be structures transported from the vitelline body into oocyte, whereas those found at the side of the follicle cells were thought to be structures made in the follicle cells and fused into the vitelline body.

• Development and Reproduction
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• v.22 no.3
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• pp.245-252
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• 2018

To improve survival rates of vitrified pig oocytes, the treatment of cytoskeletal stabilizer on an appropriate time is one of the possible approaches. However, the exact treatment timing and effect of cytoskeletal stabilizer such as cytochalasin B (CB) is not well known during oocyte vitrification procedures. Thus, the present study was conducted to determine optimal treatment timing of CB during vitrification and warming procedures. In experiment 1, the survival rates of the postwarming pig oocytes were analyzed by fluorescein diacetate (FDA) assays with 4 classifications. In results, post-warming oocytes showed significantly (p<0.05) decreased number of alive oocytes (31.8% vs. 86.4%) compared to fresh control. In detail, the significant difference (p<0.05) was found only in strong fluorescence (18.2% vs. 70.5%) not in intermediate fluorescence groups (13.6% vs. 15.9%). In experiment 2, CB was treated before (CB-Vitri) and after (Vitri-CB) vitrification. In results, group of Vitri-CB showed significantly (p<0.05) higher (91.6%) survival rates compared to group of CB-Vitri (83.7%), significantly (p<0.05) and comparable with group of Vitri Control (88.7%) by morphological inspection. In FDA assay results, group of Vitri-CB showed significantly (p<0.05) higher (44.2%) survival rates compared to groups of CB-Vitri (36.7%) and Vitri Control (35.1%). In conclusion, the increased survival rates of post-warming pig oocyte treated with Vitri-CB method are firstly described here. The main finding of present study is that the CB treatment during recovery could be helpful to refresh the post-warming pig oocyte resulting its improved survival rates.

• Journal of Applied Biological Chemistry
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• v.53 no.4
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• pp.189-194
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• 2010

We confirmed the hypo-osmotic shock strengths and duration, different type of vectors, and subcelluar localization to identify the optimum analysis condition of plant aquaporin activity in Xenopus ooctye using Arabidopsis thaliana AtPIP2-1 gene. Six minutes and 1/5ND buffer hypoosmotic shock treatment was the best condition to show the maximum swelling of Xenopus oocytes where AtPIP2-1 was expressed using pcDNA3.1 vector. AtPIP2-1 protein was expressed more efficiently in pGEMHE vector which has 5' and 3' UTR (untranslation region) of Xenopus ${\beta}$-GLOBIN gene in multiple cloning site than in pcDNA3.1 vector. Also green fluorescence of GFP fused to AtPIP2-1 was detected onto oocyte plasmamembrane where is the proper subcellular localization target of AtPIP2-1.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.3
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• pp.319-327
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• 2009

Follicular fluid meiosis-activating sterol (FF-MAS) has been suggested as a positive factor which could improve the oocyte quality and subsequent embryo development after in vitro fertilization. However, FF-MAS is a highly lipophilic substance and is hard to detect in studying the relationship between MAS and quality of oocyte maturation. The present study focused on the expression of lanosterol 14${\alpha}$-demethylase (LDM), a key enzyme that converts lanosterol to FF-MAS, on mouse oocyte maturation and its potency on development. LDM expression was strong in gonadotropin-primed germinal vesicle stage oocytes, weak after germinal vesicle breakdown (GVBD), and then strong in MII stage oocytes. The LDM-specific inhibitor azalanstat significantly inhibited oocyte fertilization (from 79.4% to 68.3%, p<0.05). Also, azalanstat (5 to 50 ${\mu}M$) decreased the percentage of blastocyst development dosedependently (from 78.7% to 23.4%, p<0.05). The specific inhibition of sterol ${\Delta}14$-reductase and ${\Delta}7$-reductase by AY9944 accumulates FF-MAS and could increase blastocyst development rates. Additionally, in the AY9944 group, the rate of inner cell mass (ICM)/ total cells was similar to that of in vivo development, but the rate was significantly decreased in azalanstat treatment. In conclusion, LDM, the key enzyme of FF-MAS production, may play an important role in fertilization and early development of the mouse embryo, especially in vitro.

• Korean Journal of Ichthyology
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• v.13 no.4
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• pp.254-260
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• 2001

In the goby Micropercops swinhonis, the follicular layer of full-grown oocytes consists of an outer layer (theca cell) and an inner layer (granulosa cell). As the oocyte grows, columnar cells of inner granulosa layer secrete mucin to their cytoplasm and then surround the oocyte. Such granulosa cells appear to be cuboidal cells in the early vitellogenesis, yolk vesicle stage, to be replaced by columnar cell secreting mucins (adhesive materials) in the middle vitellogenesis, yolk granule stage. The enveloping layer of the oocyte has a muco- follicle layer filled with mucins. The mucins are an amorphous and electron-dense substance. Interestingly, the oocyte enveloping layer becomes thickened towards the animal pole as vitelogenesis proceeds. A zona radiata of about $7.8{\sim}11.5\;{\mu}m$ thick is present below the muco-follicle layer. The zona radiata is composed of an one-layered electron-dense externa and a three to five-layered electron-less interna.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.3
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• pp.153-159
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• 2007

We studied oocyte steroidogenesis in relation to oocyte development in the greenling, Hexagrammos otakii, a marine multiple spawner. Vitellogenic and mature oocytes were incubated in vitro in the presence or absence of $[^3H]-17\;{\alpha}-hydroxyprogesterone$ as a precursor. The major metabolites were androgens [androstenedione $(A)_4)$ and testosterone (T)] and estrogens [$17\;{\beta}-estradiol\;(E_2)$ and estrone ($E_1$)] in vitellogenic oocytes. The metabolic rate of T was lower in 1.08 to 12-mm oocytes, while that of $E_2$ increased with oocyte size. The endogenous productions of T, $E_2$ and 17 ${\alpha}-hydroxy$, 20 ${\beta}-dihydroprogesterone\;(17{\alpha}20{\beta}OHP)$ were quantified using a radioimmunoassay in the non-precursor group. The endogenous levels of T and $E_2$ were highest in 1.08 to 12-mm oocytes and $17{\alpha}20{\beta}OHP$ was produced only in 1.90 to 95-mm oocytes. The relationship between oocyte size and steroidogenesis showed that 1.08 to 12-mm oocytes are full vitellogenic following induction of the maturation process. Moreover, $17{\alpha}20{\beta}OHP$ acts as a maturation inducing hormone in H. otakii.

• Clinical and Experimental Reproductive Medicine
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• v.28 no.1
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• pp.65-72
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• 2001

Objectives: This study was to investigate the fertilization rate after intracytoplasmic sperm injection (ICSI) or partial zona dissection (PZD) of human and hamster sperm into hamster oocyte in in vitro fertilization (IVF). In addition, the possibility of clinical application was evaluated by the comparison of usefulness and difference of these method. Materials and Methods: Hamster immature oocytes were obtained from oviducts superovulated by PMSG and hCG, and hamster sperms were obtained from epididymis. The freezed human sperms were thawed before use. Fertilization were confirmed by two pronuclei, one pronucleus, swollen sperm head or/and two polar bodies at $7{\sim}8$ hour after ICSI or PZD. Results: The fertilization rates after ICSI and PZD of human sperm to hamster oocyte were 3.6%, 64.2%,73.6%, and 55.6% for negative control, positive control, ICSI, and PZD respectively, suggesting that ICSI only showed improved fertilization rate (p<0.01). The fertilization rates after ICSI and PZD of hamster sperm to hamster oocyte were 11.1%, 51.2%, 39.6%, and 72.7% for negative control, positive control, ICSI, and PZD respectively, suggesting that PZD only showed improved fertilization rate (p<0.01). PZD showed significantly higher fertilization rate than ICSI (p<0.05). Conclusions: As for the fertilization rate by ICSI and PZD using hamster oocyte in IVF, ICSI technique was considered to be more useful for human sperm and PZD technique for hamster sperm. Therefore, ICSI technique was considered more appropriate for experimental application using human sperm and hamster oocyte.

• Development and Reproduction
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• v.21 no.2
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• pp.205-213
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• 2017

The aim of this study was to determine the effect of additional alpha-linolenic acid (ALA) supplementation during in vitro maturation (IVM) and culture (IVC) on nucleic maturation and embryo development of pigs. Cumulus-oocyte complexes (COCs) were incubated in IVM medium containing different concentration of ALA (25, 50 and $100{\mu}M$) for 44 h. After in vitro maturation, nuclear maturation of oocytes were evaluated by aceto-orcein stain. Mature oocytes with $50{\mu}M$ ALA were fertilized and cultured in IVC medium with ALA (25, 50 and $100{\mu}M$) during early-embryogenesis (48 hours after fertilization). Then, embryos were cultured with $25{\mu}M$ ALA during early embryogenesis and/or late embryogenesis (120 hours after early-embryogenesis). In results, oocyte maturation were significantly increased by $50{\mu}M$ ALA treatment groups compared with control groups (p<0.05). Treatment of $25{\mu}M$ ALA during early-embryogenesis enhanced cleavage rate of embryo compared with other groups (p<0.05), whereas formation and total cell number of blastocyst had no significant difference. Similarly, cleavage rate of embryos were increased by $25{\mu}M$ ALA supplement during early- or late-embryogenesis than ALA treatment both stage of embryogenesis (p<0.05), but did not influence to blastocyst formation. Interestingly, total cell number of blastocyst were enhanced in ALA treatment group during early-embryogenesis. These findings indicated that ALA supplement enhance the nuclear maturation of oocyte and embryo development, however, excessive ALA could negatively influence. Therefore, we suggest that ALA is used for improvement of in vitro production of mammalian embryo and further study regarding with functional mechanism of ALA is needed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.1
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• pp.90-97
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• 2020

The purpose of this study was to provide basic information on sexual maturity and reproductive biology for the management of biological resources in abalone Haliotis discus hannai. The nucleus of the oogonium occupied about 42% of the cytoplasm, and had a distinctive basophilic chromatin. The cytoplasm of previtellogenic oocytes was homogeneous and the size of nuclear pores increased. Fine granular and vacuolar yolk granules were observed in the cytoplasm of the initial vitellogenic oocyte. In this stage, the egg stalk and jelly membrane began to develop. The nucleus of the active vitellogenic oocyte was located near the animal pole. Yolk granules were strongly acidophilic. Lampbrush chromosomes were observed in the nucleus and rough endoplasmic reticulum. Annulate lamellae developed in the cytoplasm. The shape of the ripe oocyte was rounded polygonal. The size of ripe oocytes was 202.9±21.40×142.1±18.82 ㎛ and the thickness of the jelly membrane was 10.1±1.52 ㎛. These results show that yolk accumulation in H. discus hannai is based on two methods: exogenous accumulation, through the egg stalk, and endogenous accumulation, through intracellular organelles. Management of biological resources will be necessary when oocytes predominate after the active vitellogenic stage.

• Development and Reproduction
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• v.17 no.1
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• pp.63-72
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• 2013

A specific inhibitor of RNA polymerase II, ${\alpha}$-amanitin is broadly used to block transcriptional activities in cells. Previous studies showed that ${\alpha}$-amanitin affects in vitro maturation of cumulus-oocyte-complex (COC). In this study, we evaluated the target of ${\alpha}$-amanitin, and whether it affects oocytes or cumulus cells (CCs), or both. We treated ${\alpha}$-amanitin with different time period during in vitro culture of denuded oocytes (DOs) or COCs in comparison, and observed the changes in morphology and maturation status. Although DOs did not show any change in morphology and maturation rates with ${\alpha}$-amanitin treatment, oocytes from COCs were arrested at metaphase I (MI) stage and CCs were more scattered than control groups. To discover causes of meiotic arrest and scattering of CCs, we focused on changes of cumulus expansion, gap junctions, and cellular metabolism which to be the important factors for the successful in vitro maturation of COCs. Expression of genes for cumulus expansion markers (Ptx3, Has2, and Tnfaip6) and gap junctional proteins (Gja1, Gja4, and Gjc1) decreased in ${\alpha}$-amanitin-treated CCs. However, these changes were not observed in oocytes. In addition, expression of genes related to metabolism (Prps1, Rpe, Rpia, Taldo1, and Tkt) decreased in ${\alpha}$-amanitin-treated CCs but not in oocytes. Therefore, we concluded that the transcriptional activities of CCs for supporting suitable transcripts, especially for its metabolic activities and formation of gap junctions among CCs as well as with oocytes, are important for oocytes maturation in COCs.