Bioscientifica Proceedings

Summary. Recent research clearly shows that fusion genes can be microinjected into a pronucleus of an ovum and integrate into the pig genome. Animals with such fusion genes are called ‘transgenic’. The percentage of injected ova that developed into transgenic pigs varied among experiments from 0.31% to 1.73%. The percentage of transgenic pigs that expressed the fusion gene ranged from 17% to 100%.Eleven different regulatory s...

Abstract unavailable© 2013 Context Products Ltd...

In some situations, the pig has advantages over the mouse as a model in biomedical research. The availability of pluripotent cell lines is likely to broaden this appeal. Here we review progress in the derivation and characterization of embryonic stem cells (ESC) and induced pluripotent lines (iPSC) from pigs. Until recently, most porcine ESC failed to meet the full criteria for pluripotency, but that may be changing as more becomes known about the culture conditions requ...

Summary. Despite apparent progress in reproductive technology as applied to wild ruminants, the success achieved in terms of the number of offspring that become healthy adults has remained low. Difficulties often arise through a lack of knowledge regarding appropriate cryopreservation techniques, and indeed through a lack of detailed information on the reproductive physiology of the species in question. The Spanish ibex (Capra pyrenaica) is a wild cap...

Abstract unavailableKeywords: corpus luteum; sheep; protein kinase C; calcium; phosphoinositide turnover© 1991 Journals of Reproduction & Fertility Ltd...

It is well established that the interferon τ (IFN-τ) family of proteins play a major role in preventing the regression of the corpus luteum during early pregnancy in ruminants, such as cattle, sheep and goats, but not in other mammals. These interferons, which are structurally and functionally related to type I interferon, such as IFN-α and -ω, arose from a duplication of an IFN-ω gene approximately 36 million years ago. The IFN-τ genes have conti...

The second week of pregnancy is a particularly critical period for embryonic survival in pigs. Within that time, conceptus oestrogen synthesis is initiated, spacing and final placement of conceptuses is completed, and the signal for extending the functional lifespan of the corpora lutea is received by the mother. There is also a marked increase in blood flow to the uterus and the uterine endometrium produces and secretes nutrient histotrophe. Coneeptus-derived oestrogen h...

Abstract unavailableKeywords: progesterone; protein kinase C; intracellular calcium; prostaglandins; arachidonic acid; luteal cells; cattle© 1991 Journals of Reproduction & Fertility Ltd...

Summary. Ovine and bovine trophoblast protein-1 (oTP-1 and bTP-1) have been strongly implicated as antiluteolytic agents and responsible for maternal recognition of pregnancy in sheep and cattle, respectively. Both are interferons (IFN) belonging to the IFN-α family, but their length (172 residues versus 166 for most IFN-α) places them in an unusual subclass (the IFN-αII). The various isoforms of oTP-1 and bTP-1 produced by trophoblas...

In the ruminant ovary, synthesis and secretion of oxytocin begin in the granulosa cells of the preovulatory follicle and are markedly stimulated by the surge of LH and FSH. Luteinization of the granulosa cells results in a further increase in oxytocin gene expression, but translation ol mRNA appears to be retarded because the peak concentration of luteal oxytocin occurs later than the maximal accumulation of the message. Several hormones have been shown to stimulate oxytocin s...