• Applied Microscopy
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• v.22 no.2
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• pp.97-117
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• 1992

In order to study process of spermiogenesis of the Korean greater horseshoe bat, Rhinolophus ferrumequinum korai, the cycle of seminiferous epithelium was examined by the light and electron microscope and the following results were obtained based on the epithelial cell differentiation. 1. Spermiogenesis occurred from early July to mid-Octber, and spermatogenic activity was vigorous from mid-August to late September. Spermatocytes including spermatogonia were found to be degenerated in only July. It is deduced that the degeneration serves as the mechanism to regulate effective use of energy to prepare for mating and hibernating periods, and regulation of breeding cycle. 2. Spermiogenesis of the Korean greater horseshoe bat was divided according to differentiation of the cell structure, into Golgi, cap, acrosome, maturation and spermiation phases; Golgi, cap and spermiation phases were further divided into two steps of early and late phase respectively, and acrosome phase into three steps of early, mid and late phases, and maturation phase has only one step. Hence, the spermiogenesis consists of ten phases. The first research was done in this article on the changes of chromatin with nucleus, the time of appearance and disappearance of chromatin granules, in case of Korean greater horseshoe bat (Rhinolophus ferrumequinum korai). Chromatin granule began to be condensed in late Golgi and the condensation proceeded to form an irregular mass of a electron-dense chromatin in a form of circular cylinder in the center of nucleus at the phase of maturation. Finally, the chromatin condensation proceeded and perfect nucleus of sperm with homogeneous density was formed when the sperm was separated from Sertoli cell. Therefore, appearance and disappearance of chromatin granules occurred in the period of time between late Golgi and maturation phase, The tail of sperm began to develop in early cap phase, Numerous lipid droplets were obseved in the cytoplasm of spermatids during the maturation phase, which seemed to be used as energy source necessary to make mature sperm during spermiogenesis.

• Journal of Embryo Transfer
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• v.9 no.1
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• pp.117-125
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• 1994

In vitro development of parthenogenetic embryo was examined after ethanol treatment of follicular oocytes matured in vitro for 42, 48, 54 and 60h in the pig. The follicular oocytes were matured in TCM 199 containing 15% FCS and gonadotrophins in an atmosphere of 39 $^{\circ}C$ 5% $CO_2$. The cumulus-free oocytes were activated by 10% ethanol treatment in M2+4mg /ml BSA for 10 min. The ethanol-activated oocytes were washed and further cultured in TCM199+20%FCS containing granulosa cell monolayer. Maturation rates at 42, 48, 54 and 60h of IVM were 75.0, 86.5, 81.6 and 87.9%, respectively. Thus the oocytes maturated in vitro for longer periods did not improve nuclear maturation much. Pronuclear formation rates at 18h post-activation in ethanol-activated oocytes were 21.9, 25.0, 47.4 and 32.6%. The cytoplasmic maturation leading to pronuclear formation upon activation increased when the I VM period was extended from 42 to 54h. When the activated oocytes were cultured for 96~120h to analyse early development of the activated oocytes, the rates of embryonic development upto $\leq$ 5~8 cell were 5.3, 5.8, 12.0 and 11.7% among the cultured embryos. The result indicate that earlier development of activated porcine occyte is dependent on the duration of oocyte maturation, and that better development could be obtained from the oocyte matured for 54h.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.1
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• pp.32-37
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• 2009

This study was carried out to gather basic data on the restoration and extent of Don tea (a coin-shaped tea), the traditional tea of Korea. We examined the physicochemical components and anti-microbial activity of Don tea extracts at 0, 5 and 10 months. The Hunter value $L^*$, of Don tea extracts which were matured for 10 months decreased from 7.01 to 4.97 compared to that when the extracts were first manufactured. However, the $b^*$ value increased from 0.09 to 2.67. There were higher contents of inorganic matter in Don tea extracts following manufacture in the order of K (14.12 mg/100 mL), Mg (0.94 mg/100 mL), P (0.88 mg/100 mL), Ca (0.16 mg/100 mL) and Mn (0.16 mg/100 mL). Classified catechins contents were found in the order of C (19.97 mg/100 mL), EGC (9.30 mg/100 mL), ECG (9.02 mg/100 mL), GCG (8.50 mg/100 mL), GC (7.61 mg/100 mL) and CG (5.63 mg/100 mL). The longer the maturation period of the Don tea extracts, the lower the contents of inorganic matter and catechins. However, this did not apply to the total phenol contents, particularly in the phenol contents of Don tea extracts matured for 10 months which increased by 93.82 mg/l00 mL. Don tea extracts which were matured for longer periods showed higher anti-microbial activities against Bacillus subtilis and Streptococcus mutans. However, there were lower activities against Staphylococcus aureus, Escherichia coli and Salmonella enteritidis. Consequently, it was concluded that a shorter maturation period was required for the effective utilization of the inorganic matter, the catechins and the gram-negative bacteria in the Don tea extracts. However, a longer maturation period of 10 months was found to effectively utilize the total phenol compound contents and the gram-positive bacteria.

• Reproductive and Developmental Biology
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• v.31 no.2
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• pp.77-82
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• 2007

This study was conducted to investigate the effects of oocyte maturational age and activation condition on in vitro development of porcine parthenogenetic embryos (parthenotes). Porcine follicular oocytes were matured in vitro for 30 to 44 hr. Maturation rate was examined during in vitro maturation (IVM) every 2 hr interval. The cdc2 kinase activity was measured at 36 and 44 hr of IVM. Some oocytes were activated at 36 or 44 hr of IVM by three different conditions; 1) single electric stimulation (1.5 kV/cm for $30{\mu}sec$; ES), 2) double electric stimulations (1.5 kV/cm for $30{\mu}sec$, followed by 1.0 kV/cm for $50{\mu}sec$ after 1 hr; ES+ES) or 3) ES+ES followed by culture in 6-dimethlyaminopurine (6-DMAP) for 4 hr (ES+ES+D), and cultured for 6-7 days. Maturation rate was significantly increased as culture period was increased to 36 hr (66.9%, p<0.05), and then gradually increased to 87.1% at 44 hr of IVM. The cdc2 kinase activity was decreased (p<0.05) with culture period prolonged from 36 hr to 44 hr. Lower blastocyst formation rate (4.3%, p<0.05) were obtained by ES in 36 hr-matured oocytes compared to other treatments (16.5 and 20.5%) in the same age and the same treatment in 44 hr-matured oocytes (15.0%). High blastocyst formation rate (23.6%) was obtained by ES+ES+D in 44 hr-matured oocytes (p<0.05). These results demonstrate that porcine oocyte activation and in vitro development of parthenotes can be affected by interactions between oocyte maturational age and activation condition.

• Fisheries and Aquatic Sciences
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• v.23 no.2
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• pp.3.1-3.8
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• 2020

Background: The IGF system plays important roles in controlling growth, development, reproduction, and aging of organisms. Methods: To estimate maturation of the Pacific oyster Crassostrea gigas, we investigated the expression of insulin-like growth factor (IGF) system components and sex-specific genes. To determine the role of the IGF system in the growth and spawning period of female and male oysters, we examined mRNA expression levels of the C. gigas insulin receptor-related receptor (CIR), IGF binding protein complex acid labile subunit (IGFBP_ALS), and molluscan insulin-related peptide (MIP), as well as those of vitellogenin (Vg) and receptor-type guanylate cyclase (Gyc76C) in gonads of C. gigas collected between April and October, when sex can be determined visually in this species. Results: We found that MIP, IGFBP_ALS, and CIR mRNA expression levels were dependent on sex and month and were greater in males than in females. CIR and Vg mRNA expression levels were very similar among females, whereas IGF system components and Gyc76C were very similarly expressed among males. The highest expression values were observed in May, when oysters are mature; CIR and Vg mRNA expression levels were highest in females, and those of MIP, IGFBP_ALS, CIR, and Gyc76C were highest in males. Interestingly, we observed a 1:1 proportion of females to males during this period. Conclusion: Our results suggest that IGF system components, as well as Vg and Gyc76C, are associated with sexual maturation in C. gigas.

• Journal of Embryo Transfer
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• v.10 no.2
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• pp.115-120
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• 1995

This study was carried out to investigate On in vitro fertilization, survival rate and developmental rate of rapidly frozen bovine immature oocytes. Immature oocytes cultured for 1, 12, 24, 48 hours in 20% FCS + TCM-199 medium and thereafter rapidly freezing-thawed oocytes inseminated with capacitated sperm. The immature oocytes following dehydration by 1.5M DMSO + 2.0M glycerol + 0.25M sucrose + TCM 199 media + 20% FGS were directly plunged into liquid nitrogen and thawes in 3$0^{\circ}C$ water. Rapid freezing embryos co-cultured in 20% FCS + TCM-199 media containing hormones(21U/mL PMSG, 21U /mL hGG and 1 $\mu$g /mL 17$\beta$-estradiol) and cumulus cells(1 x 105-6 cells). Survival rate was defined as development rate on in vitro culture or FDA-test. The results are summarized as follows ; 1. The in vitro maturation and fertilization rate of immature bovine oocytes on in vitro maturation period(1, 12, 24, 48 hrs) before rapid freezing4hawed were 57.1%, 45.7%, 37.1%, 25.7% and 40.0%, 31.4%, 20.0%, 11.4%, respectively. 2. The survival rate of immature bovine oocytes on in vitro maturation period(1, 12, 24, 48 hrs) before rapid freezing-thawed were 33.3%, 26.7%, 20.0%, and 10.0%, respectively. The survival rate of rapid freezing4hawed immature oocytes was significantly lower than that of non-freezing oocytes. 3. The survival rate of rapid freezing4hawed excellent and good bovine embryos co-cultured in 20% FCS + TCM-199 media containing hormones(PMSG, hCG, 17$\beta$-estradiol) and cumulus cells 4 to 5 hrs and 20 to 24 hrs were 35.0%, 15.0% and 25.0%, 15.0% and 40.0%, 20.0% and 30.0%, 15.0%, respectively. The survival rate of embryos co-cultured in TCM-199 media containing hormones and cumulus cells was significantly higher than that of non co-culture.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.1
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• pp.43-49
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• 2020

The maturation and spawning of red seabream Pagrus major were investigated using 1,014 samples collected monthly from January to December of 2018, in the South Sea of Korea. Based on monthly changes in maturity stage and gonadosomatic index, the spawning period was estimated to be between April and August, with peak spawning occuring from May to June. Fecundity varied between 228,996 and 4,544,948 eggs. The relationship between fecundity (F) and fork length (FL) in this species can be expressed by the equation F=0.4869FL^3.9452 (R²=0.7448). Using a logistic function, the percentage of sexually mature females was estimated to be over 50% for fish with a FL of 35.3 cm.

• Reproductive and Developmental Biology
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• v.38 no.4
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• pp.143-146
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• 2014

Antioxidants, as reactive oxygen species scavengers, are one of the beneficial additives in serum-free defined culture medium. In this study, three separate experiments were performed to determine the effects of 3-hyroxyflavone added to the culture medium on the developmental competence of follicular bovine oocytes during in vitro maturation (IVM) and/or in vitro culture (IVC). The rate of blastocyst developed from oocytes cultured in IVM medium with 3-hyroxyflavone was significantly higher than that from control oocytes (39.0% vs. 26.3%, p<0.001), respectively. However, oocytes cultured in the medium with addition of 3-hyroxyflavone only at IVC period did not show significance in the blastocyst development when compared with control. When 3-hyroxyflavone was added to both IVM and IVC media, the rate of blastocyst formation was even significantly lower (21.1%) than control (26.5%; p<0.05). The present findings suggested that antioxidative activity of 3-hydroxyflavone added to only IVM medium beneficially affected the developmental competence of follicular bovine.

• Korean Journal of Animal Reproduction
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• v.19 no.4
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• pp.323-329
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• 1996

In vitro cultrue systems for the growth of sma-II oocytes and for meiotic maturation are expected to provide a new source of a large population of oocytes as well as assistance in basic physiological studies of oogenesis. Mouse oocytes mid-growth phase can complete grovvth and acquire full developmental capacity in vitro. On the other hand, growing pig oocytes need some other factors. FSH at a low concentration maintains the viability of both oocytes and granulosa cells, and hypoxanthine promotes the meiotic competence of the oocytes during culture period. Considerable improvement in the culture systems for growth of pig oocytes, suggested from mouse studies, and for oocyte maturation could help to develop this technology in larger species.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.31-31
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• 2001

This study was to establish in uitro culture system of mouse preantral follicles and to obtain higher in vitro development rates and production of live young. Preantral follicles were obtained from 12-day-old FI mouse (C57BL $\times$ CBA) by enzymatical methods. Oocyte-granulosa cell complexes (OGCs) of preantral follicles were loaded on Transwell-COL insert and cultured in $\alpha$MEM supplemented with 5% FBS, 100 mIU/$m\ell$ FSH and 100 mIU/$m\ell$ hMG for IVG. IVM was performed in $\alpha$MEM supplemented 1.5 IU/$m\ell$ hCG for 18 hrs and IVF was carried out in Ml6 medium. Embryos were cultured in modified Ml6 medium supplemented 10% FBS for 4 days. The effect of the OGCs size on the nuclear/cytoplasmic maturation was significantly higher in 120-150 ${\mu}{\textrm}{m}$ (MII: 33.0%, $\geq$2-cell: 36.7%, $\geq$morula: 20.9%) than in 70-110 ${\mu}{\textrm}{m}$ (MII: 12.2%, $\geq$2-cell: 10.2%, $\geq$morula: 4.8%) (p<0.001). In period of the IVG days, the rate of $\geq$2-cell was significantly higher in 10 days(38.2%) than in 12 days (20.0%) (p<0.01). In period of IVF time, 9 hrs ($\geq$2-cell: 31.5%, $\geq$ morula: 14.3%) indicated significantly higher cytoplasmic maturation rate than 4 hrs ($\geq$2-cell: 17.5%, This study was to establish in vitro culture system of mouse preantral follicles and to obtain higher in vitro development rates and production of live young. Preantral follicles were obtained from 12-day-old FI mouse (C57BL $\times$ CBA) by enzymatical methods. Oocyte-granulosa cell complexes (OGCs) of preantral follicles were loaded on Transwell-COL insert and cultured in $\alpha$MEM supplemented with 5% FBS, 100 mIU/$m\ell$ FSH and 100 mIU/$m\ell$ hMG for IVG. IVM was performed in $\alpha$MEM supplemented 1.5 IU/$m\ell$ hCG for 18 hrs and IVF was carried out in Ml6 medium. Embryos were cultured in modified Ml6 medium supplemented 10% FBS for 4 days. The effect of the OGCs size on the nuclear/cytoplasmic maturation was significantly higher in 120-150 ${\mu}{\textrm}{m}$ (MII: 33.0%, $\geq$2-cell: 36.7%, $\geq$morula: 20.9%) than in 70-110 ${\mu}{\textrm}{m}$ (MII: 12.2%, $\geq$2-cell: 10.2%, $\geq$morula: 4.8%) (p<0.001). In period of the IVG days, the rate of $\geq$2-cell was significantly higher in 10 days(38.2%) than in 12 days (20.0%) (p<0.01). In period of IVF time, 9 hrs ($\geq$2-cell: 31.5%, $\geq$ morula: 14.3%) indicated significantly higher cytoplasmic maturation rate than 4 hrs ($\geq$2-cell: 17.5%, $\geq$morula: 4.8%) and 7 hrs ($\geq$2-cell: 20.4%, $\geq$morula: 6.1%) (p<0.01). However, there was no difference in cytoplasmic maturation between co-cultured preantral follicle ( $\geq$morula: 17.4%) and preantral follicle cultured in Ml6 ( $\geq$morula: 17.4%). 22 morula and blastocysts produced in above optimal condition were transferred to uterus of 2 pseudopregnant recipients, 1 recipient was pregnant and then born 1 live young. This result demonstrates that in vitro culture system of preantral follicles can be used efficiently as another method to supply mouse oocyte.morula: 4.8%) and 7 hrs (2-cell: 20.4%, $\geq$morula: 6.1%) (p<0.01). However, there was no difference in cytoplasmic maturation between co-cultured preantral follicle ( $\geq$morula: 17.4%) and preantral follicle cultured in Ml6 ( $\geq$morula: 17.4%). 22 morula and blastocysts produced in above optimal condition were transferred to uterus of 2 pseudopregnant recipients, 1 recipient was pregnant and then born 1 live young. This result demonstrates that in vitro culture system of preantral follicles can be used efficiently as another method to supply mouse oocyte.