Pig embryonic stem cells (ESC) has been suggested to become important animal model for therapeutic cloning using embryonic stem cells derived by somatic cell nuclear transfer (SCNT). However, the quality of cloned embryo and derivation rate of cloned blastocyst has been presented limits for derivation of cloned embryonic stem cell. In this study, we have tried to overcome these problems by aggregating porcine embryos. Zonafree reconstructed SCNT Embryos were cultured in micro-wells singularly (non-aggregated group) or as aggregates of three (aggregated groups) at the four cell stage. Embryo quality of the cloned embryos and attachment on feeder layer rate significantly increased in the aggregates. The aggregation of pig SCNT embryos at the four-cell stage can be a useful technique for improving the quality of pig cloned blastocyst and improvement in the percentage of attachment on the feeder layer of cloned embryos. * This work was supported by the BioGreen 21 Program (PJ0081382011), Rural Development Administration, Republic of Korea.

Platygaster robiniae Buhl and Duso (Hymenoptera: Platygastridae) is a gregarious koinobiont endoparasitoid of Obolodiplosis robiniae (Haldeman) (Diptera: Cecidomyiidae). The life cycle and development of the parasite is described. P. robiniae proves to be an egg-larval parasitoid, parasitizing eggs of O. robiniae and emerging from host larvae, and eggs of the wasp develop monembryonically. Its egg and embryonic stages are prolonged to some extent. The parasitoid undergoes only one larval instar, and total development time from egg to adult takes about 28 days to complete. The life cycle of a parasitoid generation is perfectly synchronized with that of the host: the waps emerges near the emergence time of the host, so that they can parasitize host eggs.

부화 및 착상에서 prostaglandins의 역할에 대한 연구는 많으나 배아단계에 따라 포배의 팽창과 부화에 미치는 영향에 대한 연구는 미미하다. 따라서 본 실험에서는 다양한 농도의 prostaglandins를 발생단계에 따라 처리하거나, indomethacin과 prostaglandins의 양 변화를 통해 팽창과 부화에 미치는 영향을 알아보고, 배아 단계별 PG 와 PG 의 생합성양 변화양상을 알아보았다. 100M이 상 농도의 PG 처리시 거의 모든