The successful development of embryos cloned by nuclear transfer (NT)have been dependent on a wide range of known factors including cell cycle of donor and recipient ooplast, oocyte quality, NT procedure and oocyte activation. The present study compared the development of cloned porcine embryos following different activation treatments. Cumulus-oocyte complexes (COCs) were aspirated from 26 mm follicles of slaughterhouse ovaries and cultured for 22 h in NCSU #23 medium supplemented with 10% porcine follicular fluid, 0.57 mM cysteine, 0.5 g/mL LH, 0.5 g/mL FSH and 10 ng/mL EGF. The COCs were further cultured for an additional 22 h in the same medium at in an atmosphere of 5% in air, without hormonal supplements. Primary cultures of fibroblasts isolated from a female fetus on day 40 of gestation were established in DMEM + 15% FCS. For nuclear donation, cells at the 5th-6th passage were cultured in DMEM +0.5% FCS for 5 days in order to arrest the cells in G0/Gl. After enucleation, oocytes were reconstructed by transfer of donor cells and fusion with three DC pulses (1.4 KV/cm, 30 sec) in 0.28 M mannitol containing 0.01 mM and 0.01 mM . Eggs were then divided into three treatment groups, control (without further treatment, Group 1), eggs cultured in 10 g/ml cycloheximide (CHX) for 5 h (Group 2), and eggs cultured in 1.9 mM 6-dimethylaminopurine (6-DMAP) for 5 h (Group 3). The eggs were then cultured in sets of 30 in 60 I drops of NCSU#23 supplemented with 4mg/ml BSA (essentially fatty acid free) until day 7 at in a humidified atmosphere of 5% . On day 4 the culture were fed by adding 20 I NCSU #23 supplemented with 10% FBS. Development rates into blastocysts were significantly higher (P<0.05) in Group 3 embryos compared to Group 1 controls (, respectively), but rates did not differ in Group 2 compared to control (). Total cell number in Group 3 blastocysts was however significantly higher (P<0.05) than in Groups 1 and 2 (, respectively). These results suggest that 6-DMAP is more efficient than cycloheximide in the activation of electrically fused NT oocytes during in vitro production of cloned porcine embryos.

Offspring have been produced from somatic cells in a number of species. This biotechnology introduced a new phenomenon in reprogramming and differentiation of somatic cell, namely totipotency. However, birth of oversized calves and perinatal abnormalities such as increased gestation length, lack of spontaneous parturition, higher incidence of dystocia, and reduced perinatal viability of offspring are frequently observed in pregnancies of cloned bovine fetuses. Disturbance of feto-placenta has been proposed as likely causes for abnomal growth. However. Little is known the mechanism responsible for the perinatal problems. Therefore, we focused on gestation length in somatic cell nuclear recipient cows. To solve this issues, placental tissues of control and cloned bovine were obtained by a cesarean section (C-section) before 5 days of paturition. Total RNA from control and cloned bovine placenta was extractd by TRIzol reagent. GeneFishing DEG kits (Seegene) were used to identify differentially expression genes. Total RNA (3 ug) were synthesized by M-MLV reverse transcriptase (200 u/ul) with 10 uM dT-annealing control primer (ACP1) at 42C for 90 min. Then, first-strand cDNA (50 ng) was amplified using the 5 uM arbitary ACP (1-20) and 10 uM dT-ACP2 primers. Some specific expression genes were amplified, Now, we are cloning and sequencing. These finding strongly can be support to solve the problems for parturition delay in nuclear transfer cows, suggest that placenta specific proteins are key indicators for the aberration of gestation and placental function in cows.

In ultrastructure study of testis, Sertoli cells start to differentiate at 16 days of gestation. Transcripts of FSH receptor, IGF-I receptor, ER receptor and androgen receptor were highly and initially expressed at 16 day of gestation. As results of in situ PCR at 16 day of gestation, transcripts of FSH, IGF-I receptor were detected in Sertoli cells and spermatogonia, whereas the receptors of and androgen were detected in Sertoli cells. Therefore, expression of FSH and estrogen androgen, IGF-I and could play an important role during fetal and prepubertal testicular development by stage specific manner in mouse.

아열대 지역에서의 콩생육기간과 수량과의 관계를 구명하고자 1981년 대만 소재 아세아 채소연구개발센터(AVRDC)에서 선발한 콩 482계통을 봄, 여름, 가을 작기에 동일재료를 공시 생산력시험을 실시하여 얻은 결과를 요약하면 다음과 같다. 1. 작기별 평균수량 및 최고수량은 봄작기에서 높았고 가을, 여름 순으로, 낮았으며 가을 작기에서 계통간의 수량차가 제일 적었다. 2. 콩 수량은 작기에 관계없이 생육일수가 증가됨에 따라 증가되었으나 개화일수가 길어짐에 따라 수량은 감소되었다. 3. 100립중은 작기에 관계없이 결실기간이 길수록 무거운 경향을 보였으며 여름과 가을 작기에서 그 관계가 유의적이었다. 4. 다중회귀분석 결과 봄, 여름, 가을 어느 작기에서나 개화일수는 짧고 결실기간이 상대적으로 긴 계통이 고위생산력을 보이는 계통으로 고려되었다.