• 한국가축번식학회지
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• 제14권2호
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• pp.93-100
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• 1990

These experiments were carried out to investigate the effect of rabbit anti-bovine cumulus cell antibodies on in vitro maturation of bovine follicular oocytes. Antisera to bovine cumulus cell were produced Japanese Ginat rabbit by repeated immunization of intact or solubilized bovine cumulus cell and purified by ammonium sulfate precipitation and Sepharose CL-4B protein-A affinity chromatography. The bovine cumulus cell-specific antibodies were confirmed by indirect ELISA. The results obtained in these experiments were summarized as follows : 1. The titer of the antibodies to cumulus cell determined by indirect ELISA using intact or solubilized bovine cumulus cell coated plates was very high in both intact and solubilized cumulus cells. Namely, the optical density at 1:12,800 dilution of antibodies was still significantly higher than that of non-immunized control serum. 2. When the follicular oocytes were treated with antibody to intact cumulus cells, the maturation rate of cumulus compacted and removed oocytes was ranged 47.6 to 59.1%. These value is significantly lower(p<0.05) than that(78.8%) of follicular oocytes cultured without the antibody. 3. the maturation rate of cumulus compacted and removed oocytes treated with antibody to solubilized cumulus cells was ranged 46.7 to 59.1%, significantly lower(p<0.05) than that(82.1%) of ooyctes cultured in antibody free medium. From above mentioned results, it could be said that cumulus cells promote nuclear maturation of follicular oocytes and that the beneficial effect of cumulus cells to the oocyte maturation is inhibited by the action of antibody to cumulus cells.

• Archives of Pharmacal Research
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• 제18권1호
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• pp.12-17
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• 1995

It is essential to clone the preptide transporter in order to obtain better understanding of its molecular structure, regulation, and substrate specificity. Characteristics of an endogenous peptide transporter in oocytes were studied along with expression of an exogenous protor/peptide cotransporter from rabbit intestine. And further efforts toward cloning the transporter were performed. The presence of an endogenous peptide transporter was detected in Xenopus laevis oocytes by measuring the uptake of $0.25/{mu}M(10{\;}{\mu}Ci/ml)[^3H]$-glycylsarcosine (Gly-Sar) at pH 5.5 with or without inhibitors. Yptake of Gly-Sae in oocytes was significantly inhibited by $25{\mu}M$ glycine nd sarcosine. This result suggests that a selective transporter is involved in the endogneous uptake of dipeptides. Collagenase treatment of oocytes used to strip oocytes from ovarian follicles did not affect the Gly-Sar uptake. Changing pH from 5.5 to 7.5 did not affect the Gly-Sae uptake significantly, suggesting no depedence of the endogenous transporter on a transmembrane proton gradient. An exogenous $H^+/pep-tide$ contransported was expressed after microinjection of polyadenylated messenger ribonucleic acid $[poly(A)^+ -mRNA]$ obtained from rabbit small intestine. The Gly-Sar uptake in mRNA-injected oocytes was 9 times thigher than that in water-injected oocyltes. Thus, frog occytes can be utilized fro expression cloning of the genes encoding intestinal $H^+$peptide contransporters. Size fractionation of mRNA was successfully obtained using this technique.

• 한국수정란이식학회지
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• 제13권1호
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• pp.11-19
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• 1998

This study was to determine the effect of ionomycin and 6-dimethylaminopurine (6-DMAP) and/or elcetrical stimulation on the oocyte activation and production of rabbit nuclear transplant embryos. The oocytes were collected from the oviduct of superovulated rabbits at 14 h post hCG injection and cultured in TCM-199 containing 10% FBS until 19 h post hCG injection. To determine the optimum concentration and exposure time of 6-DMAP, some oocytes were activated with 5 $\mu$M ionomycin for 5 min and then in 2.0 mM 6-DMAP for 0.5 to 3.0 h, or in 1.0 to 3.0 mM 6-DMAP for 2.0 h. Other control oocytes were stimulated electrically(3X, 1.25 kV/cm, 60 $\mu$sec) in 0.3 M mannitol solution supplemented with 100 $\mu$M CaCl$_2$ and MgCl$_2$. The nuclear donor embryos of 8-cell stage were synchronized to G$_1$ phase of 16-cell stage, and the recipient cytoplasms were obtained from removal of the first polar body and a portion of membrane bound cytoplasm of the oocytes collected at 15 h post hCG injection. A separated blastomere was injected into the perivitelline space of the enucleated oocytes. The oocytes injected with nucleus were cultured until 19 h post hCG and then electrofused and activated by electrical stimulation with or without ionomycin and 6-DMAP. These nuclear transplant embryos were cultured in TCM-199 containing 10% FBS in 39˚C, 5% CO2 incubator for 120 h. For the oncytes activated parthenogenetically with electrical stimulation with or with-out ionomycin and the various concentration of exposure time of 6-DMAP, the highest cleavage(92.3%) and development to blastocyst stage(41.0%) were resulted from the oocytes activated by ionomycin and 2.0 mM 6-DMAP for 2.0 h, which were found to be significantly(P<0.05) higher than the cleavage(45.2%) and developement to blastocyst stage(14.3%) from the oocytes activated with electrical stimulation. The significantly(P<0.05) more oocytes(71.4%) developed to 4 cell stage at 24 h post activation by ionomycin and 6-DMAP than those by electrical stimulation(18.9%). For the nuclear transplant embryos, the cleavage rate was similarly high in oocyte activation by electrical stimulation with(79.4%) or without ionomycin and 6-DMAP(70.5%). However, the embryo development to blastocyst stage was significantly(P<0.05) higher in oocyte activation by electrical stimulation with ionomycin and 6-DMAP(44.4%) than by electrical stimulation only(25.0%). The significantly(P<0.05) more nuclear transplant embryos(45.6%) developed to 4 cell stage at 18 h post activation by electrical stimulation with ionomycin and 6-DMAP than those by electrical stimulation only(10.6%). These results indicated that the supplemental oocyte activation by ionomycin and 6-DMAP with electrical stimulation enhanced and accelerated the preimplanted in vitro development of the rabbit nuclear transplant embryos.

• 한국가축번식학회지
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• 제22권4호
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• pp.419-424
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• 1998

토끼 수정란의 전핵에 MT-hGH 유전자를 주입하고 핵이식 기법으로 형질전환 복제수정란의 생산효율과 PCR 검색으로 복제수정란에서 유전자존재 여부를 조사한 바 다음과 같은 결론을 얻었다. 1. MT-hGH 유전자를 주입하여 8- 및 16- 세포기로 자란 수정란을 공핵란으로 사용하여 핵이식을 실시하였던 바, 세포융합률은 각각 60.0%, 62.8% 로 비슷하였으나 정상수정란을 공급핵으로 사용한 80.4% 보다 유의적으로 낮은 융합률을 보였다. 그러나 이들 복제수정란의 체외발달률은 처리군간에 유의적인 차이는 인정되지 않았다. 2. 유전자 주입 후 8- 및 16- 세포기로 자란 수정란의 할구를 이용하여 핵이식으로 복제하고 체외에서 배반포까지 자란 수정란을 PCR -screening으로 유전자를 검출한 결과, 각각 23% 와 33% 의 유전자 양성 수정란을 감별하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제17권5호
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• pp.617-620
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• 2004

The present study compares development of rabbit embryos generated using different oocyte activation protocols and reconstructed with embryonic or cumulus cells as nuclear donor. In vivo matured oocytes were collected from New Zealand White rabbits at 16 h after ovulation treatment and were activated at18 h of post-ovulation treatment. The following schemes of oocytes activation were tested: 1) single electric pulse (EP, 3.2 kV/cm, 3${\times}$20 $\mu$s, 0.3 M mannitol)+5 min culture in the presence of 5 mM Ionomycin, 2) single electric pulse (EP, 3.2 kV/cm, (${\times}$20 $\mu$s, 0.3 M mannitol)+1 h culture in the presence of 2 mM 6-DMAP, and 3) three electric pulses 30 min apart. Cleavage rate, percentage of expanded and hatched blastocysts as well as total cell number of blastomeres of parthenogenetic embryos were significantly higher using either EP+6-DMAP or 3${\times}$EP schemes, comparing with EP+Ionomycin. Development rate up to hatched blastocyst stage of cloned rabbit embryos using the EP+6-DMAP for activation of nuclei were 19% for embryonic cell nuclei and 36% for cumulus cell nuclei. The best activation protocol optimalized in this study was the combined treatment "P+6-DMAP" which may be potentially used for nuclear transfer protocol.

• 한국수정란이식학회지
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• 제10권2호
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• pp.105-113
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• 1995

This study was conducted to examine the efficiency of enucleation and blastomere isolation from recipient oocytes and donor embryos, respectively and to determine the effect of oocyte age and electric voltage on the fusion rate and in vitro development of the fused oocytes in rabbit nuclear transplantation. Immature oocytes collected from ovarian follicles were matured in vivo for 12 h in TCM-199 containing FCS and hormones and in vivo matured oocytes were collected 17 to 18 h post-HCG. The fresh and frozen donor embryos of 8- to 16-cell stage were collected from the oviduct of superovulated does. The proportion of successfully enucleated oocytes was greatly lower in in vitro matured oocytes (42.3%) than that (62.7%) in in vivo matured oocytes The level of cytochalasin B for in vivo matured oocytes did not affect the efficiency of enuleation, but 7.5 $\mu$g /mL cytochalasin B for in vitro matured oocytes showed a high enucleation rate significantly. The isolation efficiency of a single blastomere nucleus did not differ between 8- and 16-cell stage embryos. The percentage of single blastomeres isolated from 16-cell stage fresh embryos after 0.5% pronase treatment was greatly higher at 16-min treatment (94.4%) than at 8-min(78. 1%) and the blastomeres(61.5%) isolated from frozen-thawed embryos after 16-min pronase were significantly fewer than those of fresh embryos. The age of recipient oocytes affected nuclear fusion rate. The reconstituted oocytes fused at 24-h age showed slightly higher fusion rate (77.8%) than those (65.0%)fused at 18-h age. The fusion rate of in vitro and in vivo matured oocytes inserted with fresh blastomere did not differ among electric voltages, but the cleavage rate and development to morula-blastocysts of in vitro matured oocytes was more higher under 0.6 kV/cm than under 0.8 to 1.2 kV/cm, while the cleavage rate and development of in vivo matured oocytes was higher under 0.8 to 1.0 kV/cm than under 1.2 kV/cm. The fusion and cleavage rate fol1owing insertion with frozen-thawed blastomere was not different between the in vitro and in vivo matured oocytes and was similar to those from fresh blastomere insertion.

• 한국수정란이식학회지
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• 제10권1호
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• pp.65-72
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• 1995

The purposes of this study were to produce cloned rabbit embryos and offsprings by nuclear transplantation(NT) using in vitro matured oocytes as nuclear recipient cytoplasm and to determine the effect of frozen nuclei donor embryos on the production efficiency of cloned embryos. The 8cell embryos were collected from the mated does by flushing oviducts with Dulbecco's phosphate buffered saline containing 10% fetal calf serum(FCS) at 40 hours after hGG injection. A portion of collected embryos were preserved at 4$^{\circ}C$ for 24 hours and a portion of them were frozen by vitrification method. The embryos used for donor nuclei were synchronized in the phase of Gi /S transition. The in vitro matured oocytes were used as recipient cytoplasm following removing the nucleus and the first polar body. The synchronized blastomeres from fresh, cooled or frozen embryos were injected into the enucleated oocytes by micromanipulation and were electrofused by electrical stimulation of three pulses for 60 $\mu$sec at 1.0 W /cm in 0.28 M mannitol solution. The fused oocytes were co-cultured with a monolayer of rabbit oviductal epithelial cells in M-199 solution containing 10% FCS for 120 hours at 39$^{\circ}C$ in a 5% $CO_2$incubator. Following in vitro culture of the NT embryos to blastocyst stage, they were stained with Hoechst 33342 dye for counting the number of blastomeres by fluorescence microscopy. The nuclear transplant embryos developed in vitro to 2- to 4-cell stage were transferred into the oviducts of synchronized recipient does. The results obtained were summarized as follows: 1. The fusion rates of the blastomeres from fresh, cooled and frozen embryos with the in vitro matured and enucleated oocytes were 100, 95.8 and 64, 3%, respectively. 2. Development in vitro to blastocyst was significantly(p<0.05) different between the cloned embryos with the blastomeres from fresh, cooled or frozen embryos as 39.0, 20. 9 and 15.7%, respectively. 3. The mean numbers of cell cycle per day during in vitro culture of cloned embryos blastomeres from fresh, cooled or frozen embryos was 1.31, 1.29 and 1.16, respectively. 4. A total of 77 nuclear transplant embryos were transferred into 6 recipient does, of which two offsprings were produced from a foster mother 31 days after embryo transfer.

• 한국가축번식학회지
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• 제11권1호
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• pp.73-84
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• 1987

This experiment was carried out to investigate the effects of hormone addition(FSH, HCG, estrogen and progesterone) and composition (BSA and FCS) of mKRB on the in vitro maturation and fertilizability of follicular oocytes of the Korean native cattle. The ovaries were removed at a slaughterhouse, returned to laboratory in a thermostat (30-35$^{\circ}C$) within 4 hr, and collected by aspirating normal follicles which had diameters of 1 to 6 mm. The oocytes with cumulus cells were cultured for 8, 16, 24 and 30 hr in a modified KRB solution containing BSA or FCS and hormones. The in vitro matured oocytes in mKRB containing FCS, FSH and steroids were transferred in the rabbit uterus for examination of their in vivo fertilizability with bovine sperm preincubated 4 to 6 hr in the rabbit uterus. 1. The mean number of oocytes collected per cattle was 6.5 from 1-3mm follicles, 1.3 from 4-6mm follicles, and total was 7.7. 2. The meiotic division at 16hr-cuture in the oocytes from 1-3mm follicles was slightly stimulated by the addition of FSH in mKRB + BSA solution compared with the control. At 30hr-culture, their maturation rates(%Met II) were also increased by FSH of 1 $\mu\textrm{g}$/ml(38.4%) and 5$\mu\textrm{g}$/ml(35.7%) as compared with the control (21.4%). The maturation rate at 30hr-culture in the oocytes from 4-6mm follicles was 53.8% and 57.1% by the FSH addition of 1$\mu\textrm{g}$/ml and 5$\mu\textrm{g}$/ml, respectively. These rates were similar with the control(57.1%), but higher than those of oocytes from 1-3mm follicles. 3. The meiotic division at 16hr-culture in the oocytes from 1-3mm follicles was stimulated by the HCG addition of 1IU/ml and 5IU/ml. However, the maturation rate at 30hr-culture was greatly decreased by the HCG addtion (26.6% and 13.3%) compared with the control(53.3%) and these rates (30.8%) in the oocytes from 4-6mm follicles were also lower than that fo the control(58.3%). 4. Low maturation rate (37.5%) of the oocytes cultured in mKRB containing BSA and 5IU/ml HCG was increased (55.0%) when 15% FCS with HCG was added to mKRB instead of BSA. 5. When 16hr-cultured oocytes in mKRB containing BSA and gonadotropins (5$\mu\textrm{g}$/ml FSH and 5IU/ml HCG) were transferred in the medium without gonadotropins and recultured for 16hr, the maturation rate of HCG-treated oocytes was greatly improved. 6. The maturation rates of oocytes were greatly affected by steroids. The combined addition of FCS+FSH+estrogen or +progesterone to mKRB increased the maturation rate compared with the combination of BSA+FSH or FCS+FSH in mKRB. 7. The fertilization rate, presence of pronuclei, was increased by the combination of FCS+FSH+p in mKRB as compared with that (5.6%) of BSA+FSH and the rates of FCS+FSH+steroids ranged from 12.5 to 17.6%.

• 한국수정란이식학회지
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• 제12권2호
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• pp.133-139
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• 1997

Large scale production of cloned embryos requires the technology of multiple generational nuclear transfer(NT) by using NT embryos itself as the subsequent donor nuclei. In this work we investigated comparatively the effects of enucleated oocytes treated with ionomycin and 6-DMAP on the electrofusion rate and in vitro developmental potential in the first and second NT embryos. The embryos of 16-cell stage were collected from the mated does by flushing oviducts with Dulbecco's phosphate buffered saline(D-PBS) containing 10% fetal calf serum(FCS) at 47 hours after hCG injection. The recipient cytoplasms were obtained by removing the nucleus and the first polar body from the oocytes collected at 15 hours after hCG injection. The enucleated oocytes were pre-activated by 5 min incubation in 5$\mu$M ionomycin and 2 hours incubation in 2 mM 6-DMAP at 19~20 hours post-hCG before microinjection. In the first and second generation NT, the unsynchronized 16-cell stage embryos were used as nuclear donor. The separated donor blastomeres were injected into the enucleated activated recipient oocytes by micromanipulation and were electrofused by electrical stimulation of single pulse for 60 $\mu$sec at 1.25kV/cm in $Ca^2$+, $Mg^2$+ - free 0.28 M mannitol solution. In the non-preactivation group, the electrofusion and electrical stimulation was given 3 pulses for 60 $\mu$sec at 1.25 kV/cm in 100$\mu$M $Ca^2$+, $Mg^2$+ 0.28 M mannitol solution. The fused oocytes were co-cultured with a monolayer of rabbit oviductal epithelial cells in TCM-199 solution containing 10% FCS for 120 hours at 39$^{\circ}C$ in a 5% $CO_2$ incubator. The results obtained were summarized as follows: 1. In the first generational NT embryos, the electrofusion rate of preactivated and non-activated oocytes(80.4 and 87.8%) was not significantly different, but in the second generational NT embryos, the electrofusion rate was significantly(P<0.05) higher in the non-activated oocytes(85.7%) than in the preactivated oocytes(70.1%). 2) In the first and second generational NT embryos, the developmental potential to biastocyst stage was significantly(P<0.05) higher in the preactivated oocytes(39.3 and35.7%) than in the non-preactivated oocytes(16.0 and 13.3%). No significant difference in the developmental potential was shown between the first and second generational NT embryos derived from the preactivated oocytes. In conclusion, it may be efficient to use the oocytes preactivated with ionomycin and 6-DMAP for the multiple production of cloned embryos by recycling nuclear transfer.

• Journal of Pharmaceutical Investigation
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• 제25권4호
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• pp.299-305
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• 1995

Cloning the gene encoding a dipeptide transporter is necessary for understanding the absorption mechanism of peptides and peptide-like drugs in the gastrointestinal tract. Functional expression of a dipeptide transporter after microinjection into Xenopus laevis oocytes was performed using the mRNA purified from human intestinal HT-29 cells. Fifty nanoliters of purified mRNA (1 mg/mL) were microinjected into healthy oocytes followed by incubation for 4 days in order to express a dipeptide transporter. Functional expression was determined by a uptake assay using 10 Ci/mL $[^3H]-glycylsarcosine$, a dipeptide substate of the transporter. Seasonal variability and batch-to-batch variability were greater in summer. The usage of beveled micropipettes improves viability of oocytes at 4 days after microinjection. Expression of a dipeptide transporter in oocytes after microinjection of mRNA obtained from HT-29 cells was significantly larger than those after microinjection of water or mRNA obtained from the rabbit intestine.