• Journal of Embryo Transfer
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• v.15 no.1
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• pp.23-31
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• 2000

This study was conducted to investigate the effects of quiescent treatment of donor cells and activation treatment time of recipient cytoplasm on nuclear remodeling and in vitro development of somatic cell-cloned bovine embryos. Serum starved, confluent and nonquiescent cycling adult skin cells were teansferred into enucleated oocytes. Nuclear transfer oocytes were activated at 30 min, 1 and 2 hrs after electrofusion. Some nuclear transfer embryos(23% to 35%) extruded a polar body, which was not affected by quiescent treatment of donor cells and activiation time of recipient cytoplasm. About 68% of nuclear transfer embryos fused with a serum starved cells has a chromatin clump, but which was not different from embryos fused with confluent(51%) and nonquiescent(47%) cells. The proportion of embryos with a single chromatin clump was sightly increased when nuclear transfer embryos were activated within 30 min after fusion(69%) compared to those were activated at 1 and 2 hrs after fusion, but there was not significantly different. Development rates to the blastocyst stage were 8.6% and 15.9% when serum starved and confluent cells were transferred, which were higher than that of control group. Developmental rate to the blastocyst stage was higher in embryos were activated within 30 min after fusion (17.3%) compared to those of embryos were activated at 1 and 2 hrs after fusion (P<0.05). From the present result, it is suggested that quiescent treatment of donor cells and activation time of recipient cytoplasm can affect the in vitro development. Quiescent plasm activation within 30 min after fusion could increase the number of embryos with a normal chromation structure, which results in increased in vitro development.

• Korean Journal of Veterinary Research
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• v.33 no.2
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• pp.309-320
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• 1993

Guinea pigs were cutaneously inoculated with Trichophyton verrucosum var album, that is a common causative fungus of dermatophytosis in cattle. The developmental process of lesions, clinical and histopathological changes and reisolations of the fungi were studied to evaluate the pathogenicity of Trichophyton verrucosum var album in guinea pigs. Results obtained through the experiments were summarized as follows : 1. The incidence of infection of the clipping group was 13(86%) of 15 animals, and that of the plucking group was 14(93%) of 15 animals. In both of the clipping and plucking groups, visible cutaneoas lesions were developed between 4 and 7 days post inoculation(p.i.). The spreading and the climax stages persisted for 4 to 11 and 6 to 12 days, respectively. 2. In macroscopic observations, formation of various degree of erythemas and scales over the inoculated skin sites were observed in the spreading stage. In the climax stage, exudative changes and dark red crusts were formed as typical circular lesions. In the healing stage, the lesions revealed shedding of crust, alopecia and hair regrowth. 3. In histopathological observations, infiltration of inflammatory cells, hyperplasia, microabscesses and keratinous-hyaloid materials of epidermis were observed in the spreading stage. Hyphal invasion was primarily observed at the level of epidermis and pilosebaceous ducts. In the climax stage, the infected epidermis was thick with severe hyperplasia, hyperkeratosis and acanthosis. The microabscesses with fungal hyphae, folliculitis and hyperplasia of external root sheath were observed in the dermis. The fungal hyphae were observed only in the tissues of hair follicles, that were internal root sheath, cuticle, the keratinized portions of cortex and medulla 4. In reisolation of the inoculated fungus, all trials for ten animals showed positive cultures until 25 days p.i.. Afterward, the reisolation rates were gradually decreased, showing all negative after 40 days p.i..

• Reproductive and Developmental Biology
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• v.28 no.4
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• pp.261-265
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• 2004

The present study was conducted to assess sperm characteristics in miniature-pig. The semen samples were transported to the laboratory at 17℃ within 3 hours after collection. The extended semen was stored at 17℃, and sperm quality was evaluated at 0, 1, 3, 5 and 7 days after storage. The semen volume of miniature-pig (62±22㎖) was significantly (p<0.05) lower than that of Duroc (155±25㎖) and Yorkshire (154±23㎖). Significant differences were also observed in sperm concentrations. During 3 days of storage, sperm viability did not differ among miniature-pig, Duroc and Yorkshire. However, the viability was significantly (p<0.05) lower in miniature-pig than in Duroc and Yorkshire semen after Day 3 of storage. In abnormality, acrosome intactness and intensity, there were no differences among miniature-pig, Duroc and Yorkshire semen. On the other hand, the viability of frozen-thawed sperm in miniature-pig was significantly (p<0.05) lower than in that of Duroc and Yorkshire. This study also examined CTC patterns in frozen-thawed spermatozoa. The rates of AR pattern were higher in miniature-pig than in Duroc and Yorkshire. However, no difference was found in F, B and AR patterns. The results of present study suggest that further research is necessary to develop of semen extender and freezing methods to improve sperm quality in miniature-pig.

• Korean Journal of Animal Reproduction
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• v.17 no.4
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• pp.271-278
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• 1994

The aim of this study was to compare the two culture systems 1) co-culture with cumulus cells and 2) chemically defined medium supplemented with amino acids (CR1aa) and fetal calf serum (FCS) of in vitro produced bovine embryos from follicular oocytes in vitro. Bovine follicular oocytes were collected from ovaries of slaughtered cows and matured in TCM199 supplemented with 10% FCS and hormones (1$\mu\textrm{g}$/ml FSH-P and 1$\mu\textrm{g}$/ml oestradiol-17$\beta$)24 hours at 39$^{\circ}C$ under 5% CO2 in air. The capacitation of spermatozoa from ejaculated or frozen bull semen was induced by centrifugation through Percoll density gradient (45%, 90%). Then capacitated spermatozoa (1$\times$106/ml) were inseminated into 50${mu}ell$ droplet containing matured follicular oocytes and incubated for 40~42 hours. Cleaved embryos of 2~4cell stage were transferred to the co-culture with cumulus cells and/or CR1aa medium supplemented with FCS. In semen source, the developmental rates to the blastocyst and the hatched blastocyst stages were higher in ejaculated semen(27.6% and 14.9%) than those of frozen-thawed semen(18.3% and 11.8%), respectively. In two culture systems, the proportions of embryonic development upto the blastocysts and the hatched blastocysts were higher of CR1aa medium (22.1% and 12.1%) than those of cumulus cell co-culture (16.8% and 5.1%), respectively. The number of cells in exapnded blastocysts was slightly higher in cumulus cells co-culture (122.6$\pm$8.5) than that in CR1aa medium (117.9$\pm$5.9). The present results indicated that the early development of in vitro produced bovine embryos can be maintained efficiently in CR1aa medium as well as in co-culture with cumulus cells.

• Reproductive and Developmental Biology
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• v.33 no.4
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• pp.189-194
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• 2009

The objective of this study was to determine effects of different culture media. Preantral follicles were mechanically extracted from bovine ovaries and cultured for 16 days in tissue culture medium (TCM)-199, DMEM or alpha-minimal essential medium ($\alpha$-MEM) + 10% FBS + 0.1 mg/ml sodium pyruvate + 100 mIU/ml FSH. The collected primary follicles from ovary were higher than the primary and secondary follicles. The survival rates of the follicles in TCM-199 were significantly higher (p<0.05) than those in DMEM and $\alpha$-MEM. The diameter of the follicles progressively increased during 12 days of culture. The maximum size ($139.1{\pm}5.4\;{\mu}m$) reached on Day 12 of the in vitro culture and decreased on Day 16. These results suggest that in a culture of bovine preantral follicles, TCM-199 is an optimal medium and a longer-term culture of preantral follicles (>12 days) may be needed to form antra.

• Journal of Embryo Transfer
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• v.9 no.2
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• pp.173-180
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• 1994

The present experirnents on cryopreservation were carried out to investigate effect of solution toxicity, equilibration time and cell stages on the post-thaw survival of mouse morulae and blastocyst embryos cryopreserved by vitrification in EFS solution. The mouse embryos were exposed to the EFS solution in one step at room temperature, kept in the EFS solution during different period for toxicity test, vitrified in liquid nitrogen and thawed rapidly. After the mouse morulae embryos were exposed to EFS solution for 2 and 5 ruin. at room temperature and then they were washed in 0.5 M sucrose solution and basal mediurn(D-PBS + 10% FCS), they were cultured to examined cryoprotectant toxicity induced injury during exposure, most of embryos developed to expanded blastocysts(100 and 90.0%). However, when the exposure time was extended to 10 and 20 min, these development rates dropped dramatically in 10 ruin. (75.0%) and 20 ruin. (4.5%), respectively. When the compacted morulae were vitrified in EFS solution after equilibration for 2 and 5 min, the embryos have developed to normal blastocyst following thawing, washing and culture processes was 89.3 and 89.6%. However, when the exposure time was expanded to 10 ruin, this survival rate dropped to 68.8%. When the blastocyst were vitrified in EFS solution after equilibration for 2, 5 and 10 minutes, the survival rate of embryos which developed to normal blastocyst following thawing and culture processing were 58.5, 46.7 and 22.4%, respectively. The optimal time of equilibration of mouse morula and blastocysts in EFS solution seemed o be 2 and 5 ruin.

• Development and Reproduction
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• v.13 no.3
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• pp.145-153
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• 2009

Previously, we obtained the list of genes differentially expressed between GV and MII oocytes. Out of the list, we focused on functional analysis of Zap70 in the present study, because it has been known to be expressed only in immune cells. This is the first report about the expression and its function of Zap70 in the oocytes. Synthetic 475 bp Zap70 dsRNA was microinjected into the GV oocytes, and the oocytes were cultured in vitro. In addition to maturation rates, meiotic spindle and chromosome rearrangements, and changes in expression levels of transcripts of three kinases, Erk1/2, JNK, and p38, were determined. Zap70 is highly expressed in immature GV oocytes, and gradually decreased as oocyte matured. When dsRNA of Zap70 was injected into the GV oocytes, Zap70 mRNA specifically and completely decreased by 2 hr and its protein expression also decreased significantly. Absence of Zap70 resulted in maturation inhibition at meiosis I (57%) with abnormalities in meiotic spindle formation and chromosome rearrangement. Concurrently, mRNA expression of Erk2, JNK, and p38, were affected by Zap70 RNAi. Therefore, we concluded that Zap70 is involved in MI-MII transition by affecting expression of MAP kinases.

• Korean Journal of Animal Reproduction
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• v.10 no.1
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• pp.27-35
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• 1986

As a preliminary experiment to establish the process on the sexing of mouse embryos by chromosomal analysis, present studies were carried out with inbred (ICR, C57BL) and F1 hybrid [(ICR${\times}$C57BL) = F1 ${\times}$ ICR] mice to investigate the blastomere numbers and mitotic indices (M.I.) to the developmental stage of embryos recovered, the optimum periods of anti-mitotic agent administration, the successful rates of sexing and sex-ratio. The results obtained were summarized as follows: 1. The blastomere numbers (mean${\pm}$S.E.) of the morula and blastocyst were 18${\pm}$0.4 and 54${\pm}$0.7, respectively. 2. Whereas the M.I. of F1 hybrid (16${\pm}$0.2%) was higher than that fo inbred ICR (15${\pm}$0.1%) and C57BL (12${\pm}$0.6%) in the different strains, the morula (7${\pm}$0.6%) was higher than that of blastocyst (6${\pm}$0.4%) in the case of embryo stages. 3. Following to anti-mitotic agents treated, the M.I. of embryos cultured with Colcemid (17${\pm}$1.1%) was superior to that fo embryos cultured with Velban (12${\pm}$0.9%) and the Colcemid injection (7${\pm}$0.4%). 4. The successful rate of sexing in the blastocyst (38.7%; 124/320) was superior to the morula (35.9%; 52/145), and the F1 hybrid (48.1%) was higher than that of inbred ICR (42.4%) and C57 BL (28.2%). 5. In the successful rate of sexing to the methods of administration, the embryos cultured with Colcemid (46.0%) was superior to that of embryos cultured with Velban (39.0%) and the Colcemid injection (38.8%). 6. Of 98 embryos sexed after culture with Colcemid, 89(90.8%) were observed between 2 and 4 hrs. In the case of Velban treatment, 83.1% (74/89) was observed between 2$\frac{1}{2}$ and 4$\frac{1}{2}$ hrs. 7. Out of 761 prepared embryos it was possible to sex 311; 157 were male and 154 were female, i.e.a sex-ratio of 50% a, pp.oximately.

• Reproductive and Developmental Biology
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• v.36 no.1
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• pp.87-93
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• 2012

The purpose of this experiment is to compare the pregnancy rate (PR) according to the state of the ovaries and uterus, according to the number of embryos transferred from cows and heifers and to investigate the method of artificial twin induction with Hanwoo $in$ $vitro$ fertilized (IVF) embryos by embryo transfer (ET). Looking at the PR according to the condition of the ovaries and uterus, the result was not influenced by the condition of the ovaries, but was significantly influenced by the state of the uterus. The PR according to the number of embryos transferred from cows was 36.8%, 53.0%, 50.5% for 1, 2, and 3 embryos respectively, and although there was a higher frequency of twin calves with 3 embryos than with 2, the calving rate was the highest with 2 embryos. In case of heifers, the transfer of 1 embryo showed the best pregnancy and calving rate, and although the PR was similar with 2 embryos (67.7 versus 66.4), in case of 2 embryos transferred there was high frequency of embryonic loss( 6.1%) occurred when a cow was diagnosed at 28 and 53 d after ET, total loss (21.3%; sum of fetal death, abortion and stillbirth after pregnant diagnosis at 60 day).

• Reproductive and Developmental Biology
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• v.36 no.2
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• pp.95-101
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• 2012

The purpose of this experiment was to compare the pregnancy rate (PR) according to the state of the ovaries and uterus, according to the number of embryos transferred from cows and heifers and to investigate the method of artificial twin induction with Hanwoo in vitro fertilized (IVF) embryos by embryo transfer (ET). Looking at the PR according to the condition of the ovaries and uterus, the result was not influenced by the condition of the ovaries, but was significantly influenced by the state of the uterus. The PR according to the number of embryos transferred from cows was 36.8%, 53.0%, 50.5% for 1, 2, and 3 embryos, respectively and although there was a higher frequency of twin calves with 3 embryos than 2, the calving rate was the highest with 2 embryos. In case of heifers, the transfer of 1 embryo showed the best pregnancy and calving rate, and although the PR was similar with 2 embryos (67.7 versus 66.4), in case of 2 embryos transferred there was high frequency of embryonic loss (6.1%) occurred when a cow was diagnosed at 28 and 53 d after ET, total loss (21.3%); sum of fetal death, abortion and stillbirth after pregnant diagnosis at 60 day.