• Korean Journal of Animal Reproduction
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• v.22 no.3
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• pp.253-264
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• 1998

Porcine follicular oocyte, collected from antral follicles (2~5 mm in diameter) of gilt ovaries were matured in vitro porcine follicular fluid (pFF) with PMSG (pFF-PMSG) buffer with at 37$^{\circ}C$ under 5% CO2 in air their ability of maturation promoting factor (MPF), of GV and GVBD formation was examined followed during time after in vitro culture. Formation of second metaphase was observed in 57.6% and 71.2% of matured in with pFF-PMSG buffer to 45 and 50 hours after invitro. Porcine oocytes cultured in pFF-PMSG for various periods of up to 30 hours were stained with Hoechst-33342 and classified according to maturation before assaying. Histone H1 kinase (H1K) activity was assayed during meiotic maturation in porcine oocytes matured in pFF-PMSG buffer in vitro. In oocytes matured in pFF-PMSG, H1K activity was at the 30 hours after culture and increased about 15 fold than at the germinal vesicle stage with before at the cultured in vitro. This pattern is similar to those reported in non-mammalian species and su, pp.rts the concepts that H1K is ubiquitous in eukaryotes and controls the meiotic cell cycle in mammals. These results suggest that the maturation pFF-PMSG buffer used influences the fluctuation pattern of H1K activity and biological characteristics of porcine oocytes cultured in vitro.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.2
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• pp.305-312
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• 1998

Normal tensile strength in collagen fibrils is due to intermolecular and intramolecular crosslinks which are known to be altered in aging. Pyridinoline, a mature crosslink which is stable and nonreducible, is derived from two hydroxyallysine and one hydroxylysine residues of collagen fibrils. The excess formation of pyridinoline in collagen is associated with making the tissue stiffer, less soluble and less digestible by enzymes. Lysyl oxidase is the enzyme that initiates the biosynthesis or crosslinks in collagen by catalyzing the oxidative deamination of the lysyl and hydroxylysyl residues in these molecules, and its activity is inhibited by $\beta$-aminopropionitrile(BAPN). Our previous work demonstrated that the pyridinoline content of bone collagen significantly was increased during incubation for 5 weeks at 37$^{\circ}C$ invitro, but it was diecrased by the addition of ascorbic acdi(AsA). In this study, we clarified the specific action of AsA in aging process in vitro enzymatic reaction.

• Journal of Embryo Transfer
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• v.18 no.3
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• pp.263-267
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• 2003

This study was carried out to test the efficacy of pharmacological inhibitors of the cell cycle transition in keeping bovine oocytes at the germinal vesicle(GV) stage and the reversibility of this inhibition. Bovine oocytes were incubated for 22∼24 hrs in the presence of various inhibitors : cycloheximide (2$\mu\textrm{g}$/$m\ell$), 6-DMAP (2 mM), and roscovitine (50$\mu$M). Bovine oocytes cultured with any of the inhibitors were significantly blocked at the GV stage. Reversibility of pharmacological inhibitors was assessed by culturing oocytes an additional 22∼24 hours in inhibitor-free medium. Examination of oocytes revealed that the inhibitory effect was fully reversible and effect of resuming meiotic progression on nuclear maturation varied according to the various inhibitors. This study suggests that cycloheximide, 6-DMAP and roscovitine can be applied to control meiotic arrest and resumption in maturation culture of bovine oocytes in vitro. More investigations are needed to better understand how the cell cycle of oocyte is blocked without problems to future developmental competence.

• Journal of Animal Reproduction and Biotechnology
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• v.34 no.1
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• pp.50-56
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• 2019

These studies were conducted to evaluate developmental competence of follicular oocyte collected from the ovaries of Hanwoo cows with the high offspring meat quality (1++ and 1+ grade). Cumulus oocyte complexes from individual cows were matured, fertilized and cultured using protocols of in-vitro maturation (IVM), invitro fertilization (IVF) and in-vitro culture (IVC). The rates of blastocyst development from Hanwoo cows with the offspring meat quality grades of 1++ and 1+ were 18.6 and 21.2%, respectively. The rates of blastocyst development were 26.3, 20.7, 20.7, 17.2 and 31.2% from Hanwoo cows with the meat quality grades of 1++, 1+, 1, 2 and 3, respectively. Fiftyseven transferable embryos were recovered from 11 Hanwoo donor cows (5.2/head) with the high offspring meat quality grades of 1++ and 1+ in vivo, and the pregnancy rate after embryo transfer was 61.1%. In conclusion, these results suggest that in vitro embryo production from the ovaries of cows with the high meat quality grades using individual culture system can be used an efficient method for livestock improvement. In addition, for the successful industrialization of embryo transfer, conception rate should be improved.