A total of 13 commercial hair dye products made in China were tested for mutagenicity in 2 short-term bioassays, the histidine-requiring mutants of Salmonella typhimurium (strains TA98 and TA100) and the micronucleus ...A total of 13 commercial hair dye products made in China were tested for mutagenicity in 2 short-term bioassays, the histidine-requiring mutants of Salmonella typhimurium (strains TA98 and TA100) and the micronucleus test with mouse bone-marrow polychromatic erythrocyte cells in vivo. The results showed that the 13 hair dyes were not mutagenic in strains TA98 and TA100 with and without S-9. In the micronucleus test, no mutagenic effect was observed.展开更多
Bovine fetal oviduct epithelial cells were transfected with constructed double marker selective vector(pCE-EGFP-IRES-Neo-dNdB) containing the enhanced green fluorescent protein (EGFP) and neomycin-resistant(Neo^r) gen...Bovine fetal oviduct epithelial cells were transfected with constructed double marker selective vector(pCE-EGFP-IRES-Neo-dNdB) containing the enhanced green fluorescent protein (EGFP) and neomycin-resistant(Neo^r) genes by electroporation, and a transgenic cell line was obtained. Somatic cell nuclear transfer (SCNT) was cartied out using the transgenic cells as nuclei donor. A total of 424 SCNT embryos were reconstructed and 208 (49.1%) of them developed to blastocyst stage. 17 blastocysts on D 7 after reconstruction were transferred to 17 surrogate calves,and 5 (29.4%) recipients were found to be pregnant. Three of them maintained to term and delivered three cloned calves.PCR and Southern blot analysis confirmed the integration of transgene in all of the three cloned calves. In addition, expression of EGFP was detected in biopsy isolated from the transgenic cloned calves and fibroblasts derived from the biopsy. Our results suggest that transgenic calves could be efficiently produced by SCNT using transgenic cells as nuclei donor. Furthermore, all cloned animals could be ensured to be transgenic by efficiently pre-screening transgenic cells and SCNT embryos using the constructed double marker selective vector.展开更多
Human lysozyme is a 130-aa (amino acid) alka-line polypeptide, and has both anti-bacterial and anti-viral properties which make it an important component of human natural immunity system. As a first step toward the ul...Human lysozyme is a 130-aa (amino acid) alka-line polypeptide, and has both anti-bacterial and anti-viral properties which make it an important component of human natural immunity system. As a first step toward the ultimate goal of improving the anti-bacterial properties of bovine and ovine milk, a transgenic mouse that contains the genomicDNA sequence of the human lysozme gene has been gener-ated for the first time. From 83 mice generated by microin-jection, a total of 6 positive transgenic mice were identified by PCR and Southern blot. F1 mice positive for transgene inlines were also detected by PCR. This shows that transgene could be transmitted from founder transgenic mice to their offspring. Recombinant human lysozyme (rHlys) was found in the whey of 3 female positive transgenic mice by Western blot. The highest concentration of rHlys for transgenic mice was 0.2 mg/mL. The antibacterial activity of the whey fortransgenic mice was highly enhanced up to 0.4 times as much as that of human, while that of non-transgenic mouse wasvery low. Although the lysozyme activity of transgenic mice is still lower than that of human, the rHlys exhibits the same specific activity as that of human lysozyme. It provides astrong basis for further studies into the possible application of rHlys express in mammary gland.展开更多
文摘A total of 13 commercial hair dye products made in China were tested for mutagenicity in 2 short-term bioassays, the histidine-requiring mutants of Salmonella typhimurium (strains TA98 and TA100) and the micronucleus test with mouse bone-marrow polychromatic erythrocyte cells in vivo. The results showed that the 13 hair dyes were not mutagenic in strains TA98 and TA100 with and without S-9. In the micronucleus test, no mutagenic effect was observed.
文摘Bovine fetal oviduct epithelial cells were transfected with constructed double marker selective vector(pCE-EGFP-IRES-Neo-dNdB) containing the enhanced green fluorescent protein (EGFP) and neomycin-resistant(Neo^r) genes by electroporation, and a transgenic cell line was obtained. Somatic cell nuclear transfer (SCNT) was cartied out using the transgenic cells as nuclei donor. A total of 424 SCNT embryos were reconstructed and 208 (49.1%) of them developed to blastocyst stage. 17 blastocysts on D 7 after reconstruction were transferred to 17 surrogate calves,and 5 (29.4%) recipients were found to be pregnant. Three of them maintained to term and delivered three cloned calves.PCR and Southern blot analysis confirmed the integration of transgene in all of the three cloned calves. In addition, expression of EGFP was detected in biopsy isolated from the transgenic cloned calves and fibroblasts derived from the biopsy. Our results suggest that transgenic calves could be efficiently produced by SCNT using transgenic cells as nuclei donor. Furthermore, all cloned animals could be ensured to be transgenic by efficiently pre-screening transgenic cells and SCNT embryos using the constructed double marker selective vector.
基金supported by the State High-tech Research Development Program(Grant No.2002AA206111)
文摘Human lysozyme is a 130-aa (amino acid) alka-line polypeptide, and has both anti-bacterial and anti-viral properties which make it an important component of human natural immunity system. As a first step toward the ultimate goal of improving the anti-bacterial properties of bovine and ovine milk, a transgenic mouse that contains the genomicDNA sequence of the human lysozme gene has been gener-ated for the first time. From 83 mice generated by microin-jection, a total of 6 positive transgenic mice were identified by PCR and Southern blot. F1 mice positive for transgene inlines were also detected by PCR. This shows that transgene could be transmitted from founder transgenic mice to their offspring. Recombinant human lysozyme (rHlys) was found in the whey of 3 female positive transgenic mice by Western blot. The highest concentration of rHlys for transgenic mice was 0.2 mg/mL. The antibacterial activity of the whey fortransgenic mice was highly enhanced up to 0.4 times as much as that of human, while that of non-transgenic mouse wasvery low. Although the lysozyme activity of transgenic mice is still lower than that of human, the rHlys exhibits the same specific activity as that of human lysozyme. It provides astrong basis for further studies into the possible application of rHlys express in mammary gland.
