Search

Trichostatin A, a histone deacetylase inhibitor, could increase histone acetylation, and active gene expression in somatic cells. However, effect of TSA on histone methylation is unclear. In present study, the bovine fibroblast cells were treated with TSA, and histone acetylation and methylation were examined by using indirect immunofluorescence and scanning confocal microscopy. We found that the morphology of cells was changed from being slightly concave to more flat and elongated even at the 10 ng/mL group. Intensive H4K8ac signals in fibroblast cells were observed after TSA treatment. A similar increasing with H4K8ac in H3K4me3 was found, but no change was observed at H3K9me2 when somatic cells were treated with TSA. These result indicated that TSA was not only increasing histone acetylation, but also increasing histone methylation that was correlated with gene expression. However, TSA could not change the level of histone methylation that regulated gene silence.

Bacillus Calmette-Guerin (BCG) vaccines are attenuated live strains of Mycobacterium bovis and are among the most widely used vaccines in the world. BCG is proven to be effective in preventing severe infant meningitis and miliary tuberculosis. Intravesical instillation of BCG is also a standard treatment for non-muscle invasive bladder cancer. In the past few decades, recombinant BCG (rBCG) technology had been extensively applied to develop vaccine candidates for a variety of infectious diseases, including bacterial, viral, and parasite infections, and to improve the efficacy of BCG in bladder cancer therapy. This review is intended to show the vast applications of BCG and recombinant BCG (rBCG) in the prevention of infectious diseases and cancer immunotherapy, with a special emphasis on recent approaches and trends on both pre-clinical and clinical levels.

Being one of the most important base areas for animal husbandry, Inner Mongolia has possessed total 71.12 million heads of farm animals by end of 1997. Government of Inner Mongolia has focused on the import of fine breeds from other countries through modern breeding technologies in recent years. From 1991 to 1997, about 10,000 heads of farm animal have born from embryo transfer Among which, the pregnancies of cattle in both pasture and sheds were 41.1%(241/323) and 51.6%(157/304); that of sheep and goats were 74.6%(241/323) and 79.9%(314/393), respectively. The other project is production of bovine IVF embryos and ET. From 1995 to 1996, we have produced 10,000 IVF embryos of fine breed cattle in Australia and transfered part of them mainly in Inner Mongolia. The average pregnancy and birth in from 1996 to 1997 were 19.9%(33/166) and 16.9%(28/166).In another project, the 1.5 or 3.0 month o1d kids of goats were used as oocytes donor treated with FSH-LH, and the number of follic1es, recovery of oocytes and enab1es for IVF were 42~56, 28~31, 22, respectively. The optimum duration for goat oocytes maturation is 16~20 hrs. The 2-to 4-ce11s embryos from 48 h cu1ture after IVF were transferred. By this way the F3 kids were born, and the development potential of the oocytes from kids was confirmed.

Jasplakinolide (JAS), a cytotoxic natural product, induces actin polymerization and increases microfilament assembly. The knowledge about the effect of JAS on oocyte meiosis in mammals is limited. The present study was to investigate the effect of JAS on the events of oocyte meiosis such as spindle configuration, chromosome alignment and segregation and oocyte maturation. The results showed that (1) JAS affected oocyte maturation and haploid composition of matured oocytes in a dose-dependent manner. The maturation rates were 70.3, 53.1, 39.7 and 20.6% after culturing oocytes in JAS at 100, 200, 300 and 400 nM for 24 h, respectively, which were significantly lower than the control group (86.2%); (2) JAS treatment caused drastically irregular meiotic spindle formation and destroyed microfilament organization; (3) JAS altered the chromosomal alignment, homologous chromosomal segregation and resulted in failure of PB1 extrusion. The majority of the non-PB1 oocytes was arrested at the tetrad state in which homologous chromosomes and sister chromatids were clearly visible; (4) pretreatment of oocytes with JAS affected the oocyte maturation even after subsequent incubation in normal maturation medium; (5) oocytes at metaphase I were much more sensitive to JAS than oocytes at anaphase I stage. In conclusion, JAS affected polar body extrusion, spindle morphology, microfilament organization and chromosome composition in a dose dependent manner and oocyte meiotic stage dependent manner. Key words: Jasplakinilide, oocyte meiosis, spindle, microfilament, chromosome.

In the present study, in vitro matured and fertilized ovine oocytes were cultured, and theembryos developed to 24-cell and morula-blastocyst stage were transferred into the oviducts or uteri of recipients, and the development rate and conception rate of ova were examined. The ovine oocytes were collected from local slaughter houses and cultured in a CO2 incubator (39°C, 5% CO2 in air) with TCM 199 containing 10% fetal calf serum (FCS) or normal steer serum (NSS), hCG and 17β-E2 for 24 to 26 hr. The matured oocytes with expanded cumulus were inseminated by fresh spermatozoa capacitated with ionophore A23187. After 7 to 10 hr, they were transferred into the development culture medium, i.e. Hepes buffered TCM 199 supplemented with 10% FCS (or NSS) and Pyruvate-Na. Part of 24-cell or morula-blastocyst stage embryos were transferred into recipients surgically while other embryos were cultured for 7 to 12 days for further examination of development. The results showed that the cleavage rate after 48 to 72 hr of insemination in NSS treatment was 52.4% (182/347), significantly higher than that of in FCS treatment; 61 IVF embryos were transferred into 20 recipients, 10 of them became pregnant and delivered of eleven lambs after normal gestation, the conception rate reached 50%. Among the continuously cultured cleaved ova, 64.7% (312/482) of them developed to morula-blastocyst stage (including hatched blastocysts).

Experiments were carried out to investigate influences of hormones (hCG+E2), sera (fetal calf serum, FCS; day O oestrous cow serum, DOOCS) in maturation media, and serum (D7OCS) concentration in development media on bovine in vitro fertilization and development. And the effects of different cryoprotectants (glycerol and ethylene glycol) on the freezing of IVF bovine embryos were examined. The results indicated that the hormone in the medium was important for the development of IVF bovine embryos, and 5-10% D7OCS in development medium has a effect for the embryo development. Effects of glycerol and ethylene glycol on IVF bovine embryos freezing did not show a significant difference.

Transgenic animal technology is a powerful tool for researching bioscience, biomedicine, bioreactor, and ag-riculture. There are various ways to produce transgenic animals. The most common ways currently available are pronuclear microinjection and nuclear transfer techniques. However, these methods usually result in low efficiency, causing mosaic (in pronuclear microinjection), or develop-mental abnormalities (in nuclear transfer). In 1994, Brinster and his colleagues reported an original method to transfer spermatogonial stem cells from donor to recipient mice. The donor spermatogonia were able to form spermatozoa in re-cipient testes, and to produce progeny carrying the donor’s genetic characters. Since then, a series of novel methods were invented by using spermatogonia transplantation. These new methods facilitate the research and application of sper-matogonia. Some of these methods, when combining with genetic modification methods, will form a novel methodology for creating transgenic animals. The present paper reviews the achievements of research on spermatogonia transplanta-tion related to creating transgenic animal. Such as, trans-plantation techniques, cryopreservation of spermatogonia, preparation of recipients, long-term proliferation of sper-matogonia in culture, genetic modification of spermatogonia, and characterization of germ line transmission of the modi-fied gene, etc. Furthermore the methodologies for creating transgenic animals by using spermatogonia transplantation were described. Based on the difference between donors and recipients used, the methodology is categorized into two groups: allogeneic transplantation, and autologous trans-plantation. Although progress in this research area has been swift, potential difficulties remain to be overcome in each approach. The advantages and existing problems in the methodology are discussed.