This study was performed to test the cellulose digestibility using the transgenic pigs harboring cellulose degradation gene D (CelD). After delivered offsprings between normal pig and transgenic swine, DNA was isolated from piglets tail for PCR analysis. In first generation, five out of 65 piglets showed CelD positive. Unfortunately, four CelD-positive pigs were died during growing, but one survived pig was used as a transgenic founder to produce F₁ descendents. Among 3 F₁ transgenic pigs produced, one died and the remaining two pigs were used to test the fiber digest efficiency. An assorted feed was composite of 5％ fiber with other ingredients. The feed of 3 kg per day was provided to the pigs including transgenic founders and littermate controls. The manure quantity was measured daily for a month, and all manures were dried for three days to analysis nitrogen, phosphate and fiber concentrations. The fiber digestion efficiencies of the transgenic F₁ pigs showed approximately 10％ higher than those of control pigs. Fiber digestion was not greatly improved in transgenic pigs as it had been expected approximately 30％. Nitrogen concentration of transgenic pig′s manure was slowly decreased compare to the control pigs. Because there were only two transgenic pigs tested, a large number of transgenic pigs may be necessary to obtain more reliable data. Breeding of animals to obtain sufficient transgenic pigs subjected for a further study is on progress. Taken together, this study demonstrated successful production of transgenic pigs with increase of cellulose digestibility in the porcine feed.

The effects of additions/deletions in glycosylated residues of recombinant human EPO (rhEPO) produced in CHO-K1 on their secretion were examined. hEPO cDNA was amplified from human liver mRNA and cloned into the pCR2.1 TOPO. Using overlapping-extension site-directed mutagenesis method, glycosylation sites at 24th, 38th, 83rd, and 126th were respectively or accumulatively removed by substituting its asparagine (or serine) with glutamine. To add novel glycosylation sites, 69 and 105th leucine was mutated to asparagine. Mutant and wild type rhEPO constructs were cloned into the pcDNA3 expression vector with CMV promoter and transfected into CHO cell line, CHO-K1, to produce mutant rhEPO mutant rhEPO proteins. Enzyme-linked immunosorbant assay (ELISA) and Western analysis with monoclonal anti-EPO antibody were performed using supernatants of the cultures showing transient and stable expressions respectively. Addition of novel glycosylation reduced rhEPO secretion dramatically while deletion mutants had little effect except some double deletion mutants (△24/83 and △38/83) and triple mutant (△24/38/83). This fact suggests that not single but combination of changes in glycosyl groups affect secretion of rhEPO in cell culture, possibly via changes in their conformations.

Transgenic animals production tools have been valuable for research and purpose. The current methods of gene transfer, microinjection and nuclear transfer, which are widely used in transgenic animal production, but all most methods has only had limited success in production of larger species. Here, we report the possibility of a sperm-mediated gene transfer method in porcine embryos. Oocytes were collected from ovaries harvested at a local slaughterhouse were matured in 500 drops of TCM-199 under mineral oil at 38.5 in a humidified atmosphere of 5%CO2 in air. After 42-43h of in vitro maturation oocytes were denuded. for sperm injection into the cytoplasm of the porcine oocytes, sperm suspension in NIM medium are subjected extraction with TritonX-100 before mixing with a green fluorescent gene (GFP). Sperm with Tritonx-100 were prepared by adding TritonX-100 to a final volume of 0.05% in the sperm suspension and mixing by trituration for 60s before two wishes in NIM medium at 2. A(ter wishing, sperm were mixed with TritonX-100 at followed by washes at 2. Sperm were resuspended in ice cold NIM to a final volume of 400 and 2-20ng/ DNA were triturated on ice for 60s. All microinjection was performed in HEPES-buffered CZB medium at room temperature within 2h. After culture in NCSU-23 for 72h, percent of porcine embryos transfected GFP gene are 20.7%(6/29) in 20ng/ sperm-DNA mixed group and other groups were 3.7 %(2/54)and 4.7%(3/67). These data suggests that sperm-mediated gene transfer method should be used to the production tool of transgenic pig efficiently.