• 한국임상수의학회지
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• 제27권1호
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• pp.46-49
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• 2010

In this study, we investigated the number of follicles, oocyte recovery rate and oocyte competence after in vitro maturation according to the size of follicle. And equine oocyte competence after in vitro maturation was investigated in terms of the diameter of follicle with criteria of maturation: nuclear stage after Hoechst staining. The average number of follicles per ovary with middle size (11-20 mm, 2.68) was higher than those of small (5-10 mm, 0.74) and large size follicle (> 21 mm, 1.63), therefore medium follicle (53.1%) had higher proportion than other size of follicles. The average numbers of follicle per ovary was 5.05. The rate of oocyte recovery in small (54.5%) and middle follicle (50%) was higher than that in large follicle (40.9%). After culture for 48 h in Medium 199, 50%, 45.5%, and 44.4% of oocytes from the follicles with diameters of 5-10, 11-20, > 21 mm, respectively reached the metaphase II stage. This is the first report showing number of follicle, oocyte recovery rate according to follicular size, and in vitro oocyte maturation in Jeju mare in Korea. To fulfill in vitro equine embryo production, further studies such as the seasonal effect, in vitro fertilization etc is need.

• 한국수정란이식학회지
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• 제14권3호
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• pp.177-184
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• 1999

This study was conducted to find out the effect of follicle size and oocyte type on in vitro maturation of poricine follicular oocytes. TCM-HEPEAS medium was used to basic medium, and the oocyte matured in vitro was stained with the Rapid staining method. The results obtained were summarized as follows; 1. The number of follicles an ovary was 20.5. The number of A-and B-typed oocytes an ovary was 2.34. The proportion of A-and b-types oocytes was 40% of the recovery oocytes. 2. Cumulus expanison indexes(CEI) by the follicle size were 1.62∼2.34(<2mm), 1.27∼2.28(2∼5mm) and 1.46∼2.75(>5mm). It was no differ to maturation rate by the follicle size. 3. The degree of oocyte maturation based on oocyte type did not differ for B-and C-typed oocyted but the index of oocyte type A was higher than that of b-and C-typed oocytes. 4. When follicluar oocytes were cultured for 42 hours, the proportion of the Met-II(second metaphase) stage were 22.5% (degree 1), 35.4%(degree 2) and 65.5% (degree 3).

• 대한수의학회지
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• 제36권4호
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• pp.929-939
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• 1996

The present study was undertaken to establish a relationship between bovine follicle size and oocyte diameter, compare the nuclear maturation competence of oocytes of different diameter groups and the nuclear maturation changes in Korean Native Cattle according to in vitro maturation period. To compare the relationship between follicle size and oocyte diameter, follicles were dissected, measured, and assigned to one of the following size categories($4{\geq}mm$, 3-4mm, 2-3mm, 1-2mm, and < 1mm), investigate the maturation competence in the different-sized oocytes, which were divided into three groups( < $110{\mu}m$, 110 - < $120{\mu}m$, and ${\geq}120{\mu}m$). Oocytes were cultured in the culture medium during 0, 6, 12, 18, and 24hrs, respectively, stained, and measured the nuclear maturation degree according to period. When compared the relationship between follicle size and intrafollicular oocyte diameter, oocyte diameters of three groups of ${\geq}3mm$ follicle-sized were significantly higher than < 3mm (p<0.01). After in vitro maturation, the rates reached to MI stage of < $110{\mu}m$ oocyte groups(25%) was higher than $110-120{\mu}m$ and ${\geq}120{\mu}m$ oocyte groups(11 and 10%) reached to the same stage(p<0.01), and the rates throughout MII stage of $110-120{\mu}m$ and ${\geq}120{\mu}m$ and < $110{\mu}m$(70 and 76%) groups were higher than < $110{\mu}m$(35%)(p<0.01). When nuclear maturation rates were measured according to period, < 6hr groups(7 and 10%) showed lower rates reached to MI than ${\geq}12hr$ groups(100%), 24hr groups(76%) revealed higher rates throughout MII than 18hr groups(40%). These results indicate that the preparation of oocyte for the production of in vitro fertilization embryos and nuclear transplantation ones could be adapted, as follicle increased up to appointed size there was a corresponding increase in oocyte diameter, and differences of nuclear maturation rate revealed according to oocyte diameter and maturation period.

• 한국패류학회지
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• 제32권1호
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• pp.1-7
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• 2016

북방전복에서 난자형성과정 동안 생식세포는 조직학적 특징에 따라 난원세포 (oogonium), 난황형성전기 난모세포(previtellogenic oocyte), 난황형성개시기 난모세포 (initial vitellogenic oocyte), 난황형성초기활성기 난모세포 (early active vitellogenic oocyte), 난황형성후기활성기 난모세포(late active vitellogenic oocyte) 및 완숙기 난모세포 (ripe oocyte)로 구분할 수 있다. 난자형성과정 동안 난모세포, 핵 및 인의 크기는 증가하는 경향을 보였으나 핵에 대한 인의 크기 비율은 감소하였다. 난모세포 세포질의 염색성은 H-E 염색에서 호염기성에서 호산성으로 변하였다. 난자형성과정 동안 난모세포에서 난병과 젤리층의 외막이 발달되었다. 이러한 조직학적 변화는 난모세포의 난황축적 및 산란준비과정으로 판단된다.

• 한국해양생명과학회지
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• 제7권1호
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• pp.55-59
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• 2022

연구는 갈치 Trichiurus lepturus의 성 성숙과 생식생물학적 기초 정보를 제공하기 위해 수행하였다. 난자형성과정 동안 난모세포와 핵의 크기는 증가하였으나 핵에 대한 인의 비율은 감소하였다. H-E 염색 결과, 세포질의 염색성은 호염기성에서 호산성으로 변하였다. 난황형성개시기 난모세포의 난경은 약 63.2 (±12.7) ㎛였다. 세포질에서는 호산성의 난황핵이 관찰되었다. 성숙기 난모세포의 난경은 216.6 (±24.7) ㎛였으며, GVBD (germinal vesicle breakdown)가 관찰되었다. 완숙기 난모세포의 난경은 317.9 (±80.9) ㎛였으며, 방사대의 두께는 4.2 (±1.7) ㎛였다. 난모세포의 발달형태는 난군동기발달형에 속하며, 난황 축적은 대부분의 경골어류와 마찬가지로 외재적 방법과 내재적 방법에 의한 것으로 판단되었다.

• Applied Microscopy
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• 제28권3호
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• pp.263-271
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• 1998

Oocyte maturation of the swordtail (Kiphophorus hellerii) was investigated by light and electron microscopy. In the ovary of the swordtail, various staged oocytes were observed, Mature oocytes were located in ovarian cortex, meanwhile immature ones were positioned in ovarian medulla. The oocyte was surrounded by several structures or cells such as chorion, follicle cells, follicular theaca and ovarian epithelium, respectively, from the inside toward outside. Growing and maturing oocytes healed numerous microvilli which interconnected the oocyte and the follicle cells to communicate each other. The mature oocyte had the electron dense chorion which appeared to be ultrastructure of two layers and contained pore canals. Oocyte maturation was characterized by not only the enlarged cell size and well differentiated cell organelles, brit also the increases of fat droplets, pinocytotic vesicles and yolk granules.

• Applied Microscopy
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• 제28권4호
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• pp.447-463
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• 1998

This study was carried out to investigate the histomorphological changes and the electrophoretic patterns of egg components, obtained from 100 of 2-year-old female catfishes (Silurus asotus). Female Korean catfishes collected in the vicinity of Chollabukdo have synchronous ovaries which discontinously ovulate eggs during the breeding season (from late May until early July). The fishes were killed by severing the spinal cord just posterior to the head after immobilization with tricaine methanesulfonate (MS 222). Especially, the light microscopic and ultrastructural changes of ooplasm and follicular membranes of oocytes, were examined by means of light and transmission electron microscopy. The size of the nucleoli and number of the yolk granules increased as the oocyte groved. Yolk granules were deposited in the oocyte as fluid Due to tile presence of large early and late maturing oocytes, their ovaries were enlarged, transparent, granular and greenish in color. As the percentages of fish in late maturing oocyte (LMO) and ripe oocyte (RO) stage increased from March to April, mean gonadosomatic index (GSI) values (19.95%) increased. Zona radiata changed from squamous into cuboid in shape in the early maturing oocyte (EMO) stage. Processes, microvilli, from the zona radiata and from the oocyte grow, and make contact with each other in the pore canals of the zona radiata during vitellogenesis, but are withdrawn as the zona radials becomes more compact and devoid of pore canals during oocyte maturation. Seasonal changes in the microscopic appearance of the ovaries were well correlated with those in both gonadosomatic index and macroscopic appearance. The main cytological changes such as increase in size of cell, nucleus, nucleolus, and increase in number of nucleoli and mitochondria demonstrated with electron microscopy in the previtellogenic oocytes of Korean catfish, provided evidences for important synthetic processes in an early preparatory phase of oocyte development. The electrophoretic pattern of major band in mature stage was much thicker (24 k, 66 k, 90-110k dalton) than that in previtellogenic phase.

• Asian-Australasian Journal of Animal Sciences
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• 제32권7호
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• pp.956-965
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• 2019

Objective: The main goal of this study was to provide a morphological indicator that could be used to select high-quality oocytes of appropriate meiotic and developmental capabilities in pig. The higher quality of immature oocytes, the higher success rates of in vitro maturation (IVM) and in vitro fertilization (IVF). Thus, prior to the IVM culture, it is important to characterize oocytes morphologically and biochemically in order to assess their quality. Two of the largest indicators of oocyte quality are the presence of cumulus cells and status of chromatin. To investigate the effects of porcine oocyte chromatin configurations on the developmental capacity of blastocysts, we assessed oocyte chromatin status according to follicle size and measured the developmental potency of blastocysts. Methods: To sort by follicle size, we divided the oocytes into three groups (less than 1 mm, 1 to 3 mm, and more than 3 mm in diameter). To assess chromatin configuration, the oocytes were assessed for their stages (surrounded nucleolus [SN] germinal vesicle [GV], non-surrounded nucleolus [NSN] GV, GV breakdown, metaphase I [MI], pro-metaphase II [proMII], and metaphase II [MII]) at different maturation times (22, 44, and 66 h). To assess the development rate, oocytes of each follicle size were subjected to parthenogenetic activation for further development. Finally, GV oocytes were grouped by their chromatin configuration (SN, SN/NSN, and NSN) and their global transcriptional levels were measured. Results: SN GV oocytes were more suitable for IVF than NSN GV oocytes. Moreover, oocytes collected from the larger follicles had a greater distribution of SN GV oocytes and a higher developmental capacity during IVM, reaching MII more quickly and developing more often to blastocysts. Conclusion: Porcine oocytes with high-level meiotic and developmental capacity were identified by analyzing the relationship between follicle size and chromatin configuration. The porcine oocytes from large follicles had a significantly higher SN status in which the transcription level was low and could be better in the degree of meiotic progression and developmental capacity.

• 한국수정란이식학회지
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• 제15권3호
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• pp.287-293
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• 2000

This study was undertaken to access the effects of collection method, room temperature at oocyte recovery and culture media on the oocyte quality, fertilization and cleavage rates of in vitro matured and fertilized oocytes of Korean native goats. Ovaries obtained from a slaughterhouse were transported to the laboratory and were divided into 2 groups. One group of ovaries was maintained at 30 to 35$^{\circ}C$ of the room temperature and another group was remained at 20 to $25^{\circ}C$ during oocyte recovery. The oocytes were recovered by follicle aspiration, slicing and aspiration+slicing methods from 3 groups of follicles according to size; <2 mm, 2 to 6 mm and >6 mm. The matured oocytes were inseminated with buck epididymal spermatozoa at a concentration of 3~3.5$\times$10$^{6}$ m1 and fertilization was identified when 2 pronuclei were present in the cytoplasm. Although the recovery rate per ovary obtained by the combination of follicle aspiration + slicing(19.6$\pm$2.2) method was higher than aspiration(11.7$\pm$1.1) and slicing(14.8$\pm$1.8) collection, optimal recovery according to oocyte grades resulted form ovarian slicing compared to aspiration or combined methods(P<0.05). However, no significant differences were found in the mean number(2.5$\pm$1.8; 3.3$\pm$3.3; 2.9$\pm$2.4) and the proportion of favorable oocytes(Grades I, II and III) recovered(31.6%, 36.0%, 36.4%,) according to follicle size(<2 mm; 2 to 6 mm; >6 mm). Fertilization rate was 60.0%, 67.7%, 70.6% and 56.4% and the proportion of embryos/zygotes was 11.1%, 7.1%, 5.0% and 2.8% in 20~$25^{\circ}C$/BO, 30~35$^{\circ}C$/BO, 20~$25^{\circ}C$/TALP and 30~35$^{\circ}C$ /groups, respectively.

• 한국수산과학회지
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• 제39권6호
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• pp.472-479
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• 2006

The sexual maturity and reproductive cycle of the common squid, Todarodes pacificus captured from the East Sea, Korea, between January 2004 and January 2006, were investigated by documenting changes in the gonadosomatic index (GSI), gonad development, and oocyte size frequency distribution. The GSI of females began to increase in July, reached a maximum in August, and then gradually decreased. The GSI of males increased from July to March. Using gonad histological observations, we identified four oocyte developmental stages. The changes in GSI and gonad tissue resulted in the classification of the annual reproductive cycle into the following four successive stages: immature (April to June), growing (June to July), mature (July to August), and ripe and spawning (August to March). According to the oocyte diameter size frequency distribution in the ovary, this species appeared to have asynchronous oocyte development and one spawning time.