Objective To found efficient procedure of inducing estrus in the bitch using exogenous gonadotropic hormones. Method Three groups of Beagle bitch, including anestrum, young of nonestrus and sterile aged bitches, were studied by combination of pregnant mare serum gonadotrophin （PMSG） + human chorionic gonadotropin （hCG） with different dose and administration separately. Result PMSG + hCG procedure was effective in the groups of anestrus and young bitches of nonestrus but ineffective for the sterile aged bitches （68.8% 25.0%）. Conclusion The success rate of inducing estrus with low dosage and multiple administration is markedly higher than that of the bitches with one administration.

Objective To supply some basic data for extension and application of BNX mice through observation on generally biological properties and peculiarity of tumor growth and metastasis after tumor implantation. Methods By the method of periodically measuring the weight、analyzing breeding character, graphing growth curve、examining hematological and blood biochemical parameters,we explored biological characteristics of BNX mice. At the same time，we also established tumor animal models of human gastric tumor （MKN-45） and human melanoma （SCI-375） in BNX mice through orthotopic and subcutaneous tumor implantation. Results It showed that there was a statistically significant difference of body weight between male and female BNX mice within 4?30 weeks （ P＜0.05）. The number of WBC in peripheral blood haematology of BNX mice was only equal to twenty-five percent of that of normal mice,while no statistically significant differences in biochemical parameters was observed between BNX mice and normal mice. The metastatic rates of orthotopic implant models of human gastric tumor （MKN-45） and subcutaneous implant models of human melanoma （SCI-375） in BNX mice were much higher than in nude mice and SCID mice.Conclusions These results suggest that BNX mice are more suitable for the study of establishment of tumor metastatic models compared with nude mice and SCID mice.

Objective To investigate the antitumor effect of anthocyanidin on lung cancer NCI-H460 cells in vitro and in vivo. Methods Cells proliferation and viability were analyzed by cells count and trypan blue exclusion assay，the inhibitory ratio of NCI-H460 cells was measured by MTT assay, the IC50 value was calculated, cells apoptosis were detected by DNA agarose gel electrophoresis, lung cancer cells NCI-H460 were subcutaneously injected into nude nice to establish cellular transplantation tumor nude mice model，and anthocyanidin were administered to the tumor-bearing nude mice,the kinetics of tumor formation and tumor growth were measured. Results After treatment of anthocyanidin, NCI-H460 cells viability decreased obviously, NCI-H460 cells proliferation were remarkably inhibited by different concentrations of anthocyanidin and the inhibition was both in time-and dose-dependent manner, the IC50 values were 90.8 jug/ml. The typical DNA ladder on agarose gel electrophoresis for analysis of cellular apoptosis were significantly appeared. Anthocyanidin can inhibit the tumor growth of nude mice. Conclusion Anthocyanidin can inhibit NCI-H460 cells proliferation, induce cell apoptosis and inhibit the tumor growth of nude mice.

According to the sequence of the nuc gene, which encodes the thermostable nuclease （TNase） of Staphylococcus aureus （ S. aureus）, a pair of oligonucleotide primers which are special to the sequence of nuc gene were designed and synthesized. Using the genome DNA of the clinically isolated strain of S. aureus SA. m0109 as template, the fragment flanking nuc gene was amplified by Polymerase Chain Reaction （PCR）. The expected size fragment was obtained and was cloned into the plasmid pGEM-T. The recombinant plasmid of pGEM-NUC was identified by restriction enzyme analysis, PCR and sequencing, which proved completely its validity.

Objective To test the expression of recombinant plasmid pcDNA-L1 and evaluate its efficiency to induce specific humoral immune responses. Methods The local HPV16-L1 gene was generated by polymerase chain reaction, inserted into pGEM-T Easy cloning vector, and then subcloned into the eukaryotic expression vector pcDNA3.1（-）. The expression of recombinant plasmid pcDNA-L1，transferred in Cos-7 cells, was identified by immunofluorescence. The 6-week-old BALB/c mice were immunized via muscular 3 times with pcDNA-L1, thereafter the sera antibody of were measured by immunofluorescence and western-blot. Results With the immunofluorescence technique, L1 protein was found to express transiently in the transfected cells of the pcDNA-L1. Specific anti-HPV16-L1 antibodies could be detected by IFA at the end of 30,60 and 180 days after the first immunization, No specific antibodies could be detected in the control group of pcDNA3.1（-）. Conclusions The recombinant plasmid pcDNA-Ll DNA constructed by us could induce specific immuno-humoral response in mice.

Objective To investigate the age-related changes in motor function’spontaneous activity and cognitive function of C57BL/6N mice. Methods Different aged, include 3,6,12,16 and 20 months old, groups of mice was constituted. Both rolling-bar test and pole-climbing test were performed to assess motor function. A computer-aided device was applied to rating spontaneous activity, and step-down test to evaluated the passive avoidance memory. Results 6 months old group of mice have significant longer rolling bar test latency than those of other groups ( P＜0.05) and also manifest a shortest pole-climbing time ( P＜0.05). 6，12 and 16 months old groups show a significant more spontaneous activity than those of other groups ( P＜0.01). There is an age related decline in the performance of step-down passive avoidance test. Conclusion The age-related changes of motor function, spontaneous activity and cognitive function of C57BL mice have different patterns during ageing.

Three factors ,cytochalasin B （CB） pre-treatment,width of two electrodes and field strength of electric pulse （direct current）related to the parthenogenetic activation of rabbit eggs by electric stimulation were studied for nuclear transplantation. The results showed that the treatment of oocytes with 7.5 mg/L CB for 1 h followed by activation with electrical stimulation significantly improved the oocyte activation rate as compared with the oocytes without CB pre-treatment （79.4% vs 48. 1%， P＜0.05）. The activation rate of oocytes which were placed between the two electrodes with 0. 50mm apart was signifi-cantly improved as compared with the two electrodes with 0.25 or 1.00mm apart （79.4% vs 63. 1% or 35.0%, P＜0.05）. Furthermore,a high activation rate（90.9%）and develop-ment rate （47.5%） were achieved when oocytes were activated electrically with a field strength of 3.0 kV/cm（50μs） versus 1. 8,2.4,3.6 kV/cm.

The high concentration ethylene glycol （EG-8，8 mol/L） and galactose（1.7mol/L） were used as a cryoprotectant and thawing diluents for embryo cryopreservation by vitrification in MMTV-Wnt-1 transgenic mice. The best results of cryopreservation were obtained if those embryos kept balance in EG-2 （2mol/L） for 4～6 minute before freeze and thawing 3～5 minute in galactose. The percentage of embryos cryopreserved and retrieve is 88. 61% （109/123）； there is 88. 99%（97/109）of these embryos develop and 81. 65%（89/109）developing to hatch blastocysts. After these development embryos were transfer to pseudocyesis mouse, 38. 36%（69/181） developed to live young, and a half of these is positive mouse on the PCR test. It follows that high concentration ethylene glycol and galactose as a cryoprotectant for cryopreseveration by vitrification is effective.

The origin and breeding of the immunodeficient animal——T、B、NK cell deficient mouse (BNX mouse) was reviewed and the biological characteristics and applications in haematol-ogy、oncology、immunology and other fields were given in details.

To establish an effective method for identifying the vitality of mouse embryos, the embryos were stained with trypan blue in different concentrations diluted by PBS （1：6, 1：4，1：3, 1：2，1：1，1：0） and cultured separately for each group. The results revealed that the developing rates were 70.7%,66.5%,77.0%,60.0%,45.0% and 30.0% respectively. The results suggest that the 1：3 staining concentration is optimal. It was further confirmed by the electron microscopy.

Briefly illustrating concepts and the primary technical procedure of gene targeting,and systematically introducing selective methods and gene targeting strategies. Gene targeting has been widely used in the fields of gene function research,the inheritance and improvement of livestock, construction of the diseasel animal models and gene the rapy.