• 한국발생생물학회지:발생과생식
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• 제17권4호
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• pp.421-426
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• 2013

In this study, oocyte steroidogenesis are investigated in relation to oocyte development in the starry flounder, Platichthys stellatus, a marine multiple spawner. Vitellogenic (0.52 and 0.55 mm oocyte diameter) and mature oocytes (0.63, 0.66 and 0.71 mm oocyte diameter) were incubated in vitro in the presence of $[^3H]17{\alpha}$-hydroxyprogesterone ($[^3H]17{\alpha}$-OHP) as a precursor. Steroid metabolites were extracted from the incubated media and oocytes, the extracts were separated and identified by thin-layer chromatography (TLC), high performance liquid chromatography (HPLC) and gas chromatographymass spectrometry (GC-MS). The major metabolites produced from $[^3H]17{\alpha}$-OHP were androgens [androstenedione ($A_4$) and testosterone (T)] and estrogens [$17{\beta}$-estradiol ($E_2$) and estrone ($E_1$)] and progestins [$17{\alpha},20{\alpha}$-dihydroxy-4-pregnen-3-one ($17{\alpha}20{\alpha}P$) and $17{\alpha},20{\beta}$-dihydroxy-4-pregnen-3-one ($17{\alpha}20{\beta}P$)] in vitellogenic and mature oocytes. The results from this study suggest the potential roles of $E_1$ in the oocytes with diameter 0.52-0.71 mm, $17{\alpha}20{\alpha}P$ and $17{\alpha}20{\beta}P$ at the oocytes of 0.63, 0.66 and 0.71 mm.

• 한국수정란이식학회지
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• 제12권1호
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• pp.1-10
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• 1997

The present study was conducted to investigate the influence of embryo cell stage at 18h post-fusion and oocyte preactivation on sebsequent in vitro developmental potential in the nuclear transplant rabbit embryos. The embryos of 16-cell stage were collected and synchronized to G$_1$ phase of 32-cell stage. The recipient cytoplasms were obtained by removing the first polar body and chromosome rnass from the oocytes collected by non-dis-ruptive microsurgery procedure. The separated G$_1$ phase blastomeres of 32-cell stage were injected into non-preactivated recipient cytoplasms. Otherwise, the enucleated recipient cytoplasms were preactivated by electrical stimulation at 18h post-hCG injection and the separated G$_1$ phase blastomeres of 32-cell stage were injected. Mter culture until 20h post-hOG injection, the nuclear transplant oocytes were electrofused by electrical stimulation. The fused nuclear transplant embryos were classified into 3~4-cell, 2-cell and 1-cell stage at 18 hrs post-fusion and cultured until the embryos reached blastocyst stage. The developmental rate to blastocyst stage was significantly (P <0.05) higher in all the reconstituted embryos of 3~4-cell stage(58.0%) than in 2 and icell stage. The developmental rate to blastocyst stage in the embryos of 3~4-cell stage at 18 hrs post-fusion was significantly (P<0.05) higher in the reconstituted without oocyte preactivation(77.8%) than in the oocyte-preactivated embryos (33.3%). These results indicated that the higher rate of in the in vitro development to blastocyst stage might be obtained form the embryos which were reconstituted with nuclear donor of G$_1$ phase and non-preactivated oocyte, and developed more rapidly for 18 hrs post-fusion.

• 농업과학연구
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• 제44권3호
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• pp.309-317
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• 2017

Melatonin (N-acetyl-5-methoxytryptamine) is an indole synthesized from tryptophan by the pineal gland in animal. The major function of melatonin is to modulate circadian and circannual rhythms in photoperiodic mammals. Importantly, however, melatonin is also a free radical scavenger, anti-oxidant, and anti-apoptotic agent. Recently, the beneficial effects of melatonin on oocyte maturation and embryonic development in vitro have been reported in many species such as pig, cattle, sheep, mouse, and human. In this review, we will discuss recent studies about the role of melatonin in the production of porcine and bovine oocytes and embryos in vitro in order to provide useful information of melatonin in oocyte maturation and embryo culture in vitro.

• 한국발생생물학회지:발생과생식
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• 제21권2호
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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.

• 한국발생생물학회지:발생과생식
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• 제18권2호
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• pp.117-125
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• 2014

Vitrification method is widely used in oocyte cryopreservation for IVF but the birth rates are lower than that of the fresh oocyte. One of the known main reasons is structural instability of meiotic spindle and chromosome systems of mature oocyte. To get the best way for keeping competence of matured oocytes, we studied the best conditions for vitrification focused on equilibration times. The mature oocytes were underwent vitrification with current popular method and analyzed the survival rates, microtubule stability and DNA integrity. The survival rates of recovered oocyte are almost same between groups and are more than 93%. The structural configuration of meiotic spindle was well kept in 10 min equilibration group and the stability rate was almost same with that of control. The chromosomal breakdown was observed in all experimental groups, but the chromosomal stability was higher in 10 min equilibration group than the other groups. The 10 min equilibration group showed best condition compared with the other groups. Based on these results, the equilibration time is one of the key factors in successful keeping for competence of mature oocyte. Although, more fine analysis about the effects of physical stress on oocyte during vitrification is needed to define the optimal condition, it is suggested that the optimal equilibration time to get competent oocyte in mouse is 10 min. Information acquired this study may provide insight into intracellular structural events occurring in human oocytes after vitrification and application for cryopreservation of human oocyte.

• 한국패류학회지
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• 제30권4호
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• pp.333-342
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• 2014

Ultrastructural studies of oogenesis in oocytes, oocyte degeneration associated with the follicle cells in female Coecella chinensis were investigated for clams collected from Namhae, Geongsangnam-do, Korea. In this study, vitellogenesis during oogenesis in the oocytes occured by way of endogenous autosynthesis and exogenous heterosynthesis. Of two processes of vitellogenesis during oogenesis, the process of endogenous autosynthesis involved the combined activity of the Golgi complex, mitochondria and rough endoplasmic reticulum. whereas the process of exogenous heterosynthesis involved endocytotic incorporation of extraovarian precursors at the basal region of the oolema of the early vitellogenic oocytes prior to the formation of the vitelline coat. It is assumed that the follicle cells were involved in the development of previtellogenic and early vitellogenic oocytes and appear to play an integral role in vitellogenesis in the early and late vitellogenic oocytes by endocytosis of yolk precursors, and also they were involved in oocyte degeneration by assimilating products originating from the degenerated oocytes, thus allowed the transfer of york precursors needed for vitellogenesis (through phagocytosis by phagolysosomes after spawning). Follicle cells presumably have a lysosomal system for breakdown products of oocyte degeneration. and for reabsorption of various phagosomes (phagolysosomes) in the cytoplasm for nutrient storage during the period of oocyte degeneration.

• 한국동물학회지
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• 제18권2호
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• pp.87-101
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• 1975

dbcAMP에 의한 卵子의 核 崩壞 抑制作用을 電子顯微鏡的으로 究明하기 위하여 생쥐 濾胞卵子의 微細構造를 관찰하였던 바 다음과 같은 結論을 얻었다. 1. 實驗群에서의 核膜의 彎曲은 對照群의 것에 비하여 얼마간 줄고 있으며 2種의 核膜이 정상적으로 유지되고 있으나, 核膜을 따라 무수히 많은 核膜孔이 나타나고 있다. 이는 核 崩壞 抑制와 연관성이 있는 것으로 추정할 수 있다. 2. mitochondria는 對照群에서는 細胞質 전체에 산재해 있고, cristae의 構造가 뚜렷하지 못한 未分化 혹은 移行型의 것들이 많은 반면, 實驗群에서는 mitochondria가 대체로 核 周邊部에 모여 있으며 cristae가 얼마간 발달한 상태를 나타내고 있다. 3. Iysosome은 實驗群에서 그 構造도 보다 단순하고 또 그 數도 對照群에 비하여 얼마간 減少하고 있다. 4. Golgi complex는 對照群에서는 전현적인 顆粒, 層板狀 構造를 하고있으나, 實驗群에서의 것은 그다지 뚜렷하지가 않다. 5. multivesicular body는 兩群이 모두 다수 나타나고 있으며, tonofilament도 무수히 존재하고, 細胞質 전반에 걸쳐 free ribosome이 존재하고 있다. 6. 細胞膜의 microvilli의 形態는 實驗群에서는 無定形으로 변하고 있으며, perivitellin space도 상당히 넓어지고 있다. 7. 以上의 觀察結果로 미루어 보아 dbcAMP를 處理하여 24시간 배양한 卵子와, 卵巢에서 직접 採取한 卵子의 電子顯微鏡的 構造에는 근본적인 변화는 볼 수 없으며, 實驗群의 卵子에서 核膜孔의 數가 뚜렷이 증가하고 있는 것은 dbcAMP가 核膜의 透過性에 어떠한 영향을 미치므로써 卵子의 成熟을 억제하고 있는 것이 아닌가 보인다.

• Clinical and Experimental Reproductive Medicine
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• 제26권3호
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• pp.399-405
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• 1999

Objective: In the preparation of ICSI, cumulus and corona cells should be removed from the oocytes by using a combination of enzymatic (hyaluronidase) and mechanical (pipetting) methods. But little is known about the effects of different degrees of oocyte denudation and incubation time between denudation and sperm injection on the outcomes of ICSI. The aim of this study was to evaluate the effects of varying the degrees of oocyte denudation and the lengths of incubation time from denudation to sperm injection on the outcomes of ICSI. Methods: In experiment 1, patients (oocytes) were grouped into group A and B according to the degree of denudation, complete and partial, respectively. In experiment 2, patients (oocytes) were grouped into group I, II and III according to the length of incubation time of denuded oocytes until sperm injection as < 1, $1{\sim}2$ and >2 hours, respectively. Results: There was no significant difference between the degree of oocyte denudation on the survival, fertilization and development rates after ICSI procedure. In case of the incubation time of denuded oocytes until ICSI, survival rates was higher in group III (83.1 %) than in group I (61.5%, p<0.05) or group II (64.3%). However no statistically significant differences were found between incubation time and fertilization or development rates. Conclusions: This study reveals that the outcomes of ICSI are not affected by the degree (complete or partial) of oocyte denudation. However, the denuded oocytes with incubation period of more than 2 hours show better outcomes of ICSI than those with the incubation period of less than 2 hours.

• 한국수산과학회지
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• 제40권3호
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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.

• 한국양식학회지
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• 제2권1호
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• pp.21-32
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• 1989

이스라엘 잉어 난모세포의 발달단계와 혈청중 호르몬 농도의 변화를 알기 위해서 2월부터 3월까지 본 연구를 수행했다. 본 연구에서 얻어진 결과는 다음과 같다. 1. 난소가 발달되는 3월에 들어와서 혈청중 LH 수준이 급격히 상승하기 시작했다. 2. LH 수준은 G.S.I.의 변화와 높은 상관관계에 있었다. 3. 3월경부터 G.S.I.가 급격하게 증가했다 4. 3월중에는 성숙단계가 상당히 증가했다. 5. Early Perinuclcolus oocyte가 late perinucleolus core로의 빠른 발달을 나타냈다. 6. 난황이 축적됨으로써 late perinucleolus oocyte가 초기성숙단계인 oocyte로 되는 시기에 vitellogenesis가 시작되었다. 7. Oocyte가 후기성숙단계에 도달했을 때 세포질내에 난황으로 가득 채워졌다. 8. 이스라엘 잉어 난소의 헌미경적 형태의 변화는 G.S.I. 외관상의 변화와 연관성이 깊었다 9. LH는 이스라엘 잉어의 성성숙에 중요한 역할을 수행하는 것으로 나타났다.