Upstream regulatory region of 14 alleles were studied for polymorphism in BoLA-DQB loci. URRs of each allele were amplified by the polymerase chain reaction. The PCR products were cloned and sequenced. Alignment of the URR sequences showed that each DQB·exon2 alleles linked with 2 different URR sequences, thus, of 14 DQB alleles analyzed, a total of 15 different DQB-URR were found. Regulatory elements W box，X box，Y box，CCAAT box and TATAlike box which were associated with the expression of structural gene were found in all the URR sequences. W box，X box，Y box and TATA-like box were polymorphic, CCAAT box was conserved. Polymorphic sites also existed between the regulatory elements. This perhaps affected the level of expression of structural genes.

Poly (A)⁺ RNA were purified using Oligotex mRNA Kits (Qiagen) from peripheral blood leukocytes of 20 Holstein cows with mastitis and 20 health Holstein cows in lactation as control; single- and double-stranded cDNA were synthesized from the poly(A)+ RNA using PCR-Select^TM cDNA Subtraction Kit (Clontech) and further digested using RsaⅠ into cDNA fragments sized from 400 to 600 bp (dscDNA); dscDNAs from the mastitis cows (as tester) were divided into two portions which were ligated separately with a different cDNA adaptor; the ligated cDNA were hybridized twice with the dscDNA of the healthy cows at 68 ℃ for 8 h each; the products after double hybridizations were diluted by 200 times and then used for suppression PCR twice; the secondary PCR products was inserted into PGEM-T vector and transformed into E.coli TOP10 competent cells; 610 positive clones were obtained; identification of the inserted cDNA fragments in subtractive library was done using PCR. The results showed that there were inserted fragments sized by 250~750 bp in the 16 randomly selected positive clones, which would provide useful baseline for screening and cloning specific mastitis resistant genes and understanding the molecular mechanism of mastitis resistance in dairy cow.

Seven Chinese local pig breeds, including Beijing Black pig, Yimeng Black pig, Laiwu pig, Bama Small pig, Diannan Small-ear pig, Wuzhishan pig, Xiang pig, and three foreign breeds, including Large White, Landrace and Duroc were used as experimental examples. A mutation in exon4 of pig Pit-1 gene in seven Chinese local breeds was found by using PCR-SSCP analysis. A RsaⅠ restriction enzyme polymorphic site in three foreign introduced breeds was detected by using PCR-RFLP analysis. The result of population genetics analyses showed that in the mutation of exon4, the frequency of A allele and AA genotype were significantly higher than B allele and BB genotype in the most of seven Chinese local breeds. A chi-square analysis suggested that Beijing Black pig and Bama Small pig reached Hardy-Weinberg equilibrium(P＞0.05), Beijing Black pig, Yimeng Black pig, Bama Small pig, Diannan Small-ear pig and Xiang pig had intermediate polymorphism(0.25<PIC<0.5). For RsaⅠ-RFLP, the frequency of A allele and AA genotype were higher than B allele and BB genotype. Large White and Duroc reached Hardy-Weinberg equilibrium(P＞0.05); and all of the three foreign introduced breeds had intermediate polymorphism(0.25<PIC<0.5).

The Inhibin α-subunit coding sequence of Xupu goose optimized according to common codons of E.coli．The ends of F₁ and R₁ were designed with recognition sites restriction enzyme，SacⅠ and XhoⅡ．Maturation zone of Inhibin α-subunit was amplificated from granular cell of Xupu goose ovarian follicle by RT-PCR.The recombinant plasmid pMD-18T-IB was constructed by inserting the fragment of 354 bp obtained by PCR into pMD-18T vector.The sense clone from JM109 cell was evaluated by double enzyme digestion and PCR.DNA sequence analysis showed that the cloned sequence was the very fragment we designed. Those showed we obtained clone vector of Xupu goose inhibin α subunit.This construction was digested with SacⅠ and XhoⅠ and ligated the pET-28a vector digested with the same enzymes using T4 DNA ligase．One construction was generated by transforming the plasmid IB-pET-28a to the competent cell of BL21（DE3）.The sense clone was induced by IPTG．The expression of Swine myostatin was observed on SDS-PAGE.

Using the method of “random sampling in typical colonies of the central area of the habitat ” and several electrophoresis techniques, the variations of 16 structural loci encoding blood proteins in Smalltailed Han sheep and Tan sheep were examined and compared with those of three other sheep populationsMongol sheep, Hu sheep and Tong sheep to explore their genetic differentiation. The coefficients of genetic differentiation at the structural loci were all below 7.341 7% except for Alp and X-p loci. The differences among populations were less than 5.370 5%. The standard genetic distance and fuzzy clustering showed the phylogenetic relationships among Mongol sheep and each of Hu sheep, Tong sheep, Small-tailed Han sheep and Tan sheep gradually estranged. Whether genetic approach degree was fit to compare the relationships among the analyzed populations and their known founder′s modern population or not needed further verification. This study further affirmed Small-tailed Han sheep and Tan sheep had the properties of Mongol sheep and revealed partial genetic differences of five sheep populations based on the structural loci.

The genetic polymorphisms of Xi’an population of Chinese Holstein cattle were detected for κ-cn, β-lg, β-lg 5′flanking region, CSN1S2F and IGFBP-3 genes by PCR-RFLP. No carriers of the allele of CSN1S2F were found and its polymorphism information content was 0. κ-cn locus showed low polymorphism (PIC=0.236 6), the three loci of β-lg, β-lg 5′flanking region and IGFBP-3 genes moderate polymorphisms (0.316 8, 0.368 9 and 0.443 9 respectively). The heterozygosity (h) and DNA polymorphisms of the five loci (κ-cn,β-lg,β-lg 5′flanking region, IGFBP-3 and CSN1S2F genes ) were 0.274 2, 0.394 7, 0.487 9, 0.489 1, 0.000 0 and 0.025 5, 0.011 6, 0.033 3, 0.011 2, 0.000 0 respectively. And κ-cn, β-lg, β-lg 5′flanking region and IGFBP-3 loci in the population were at Hardy-Weinberg equilibrium. Only BB genotype was found at CSN1S2F loci.

Appearance, biochemical and molecular genetic markers were applied into the process of Mohair production using Angora goat gradebreed Jianchang black goat in order to establish crossbreeding program. Angora goat, Jianchang black goat and their generations F₁, F₂, F₃ and H were all studied in this research. The results of appearance genetic markers research showed that the individuals of white wool in F₂， F₃ and H generations were 93.5% ，100% and 100% respectively. The percentages of homogeneity and nearly homogeneity individuals in F₂ ，F₃ and H generations were 27.7%，70.2% and 65.3% respectively. The Mohaw yields of adult mals and females increased with the increased of generations ，but which not reached marked difference level between F₃ with H and F₂，H with F₃(P＞0.05). The average adult body weights increased in F₁ and F₂ generation，but is not marked in F3 generation(P＞0.05)， declined in H generation(P>0.05). The study of biochemical genetic marker demonstrated that average gene heterozygosity and gene consistency in Agora goat, Jianchang black goat, F₃ and H generations were 0.113 1 and 0.886 9, 0.062 1 and 0.937 9， 0.110 3 and 0.889 7, 0.110 4 and 0.889 6 respectively. The genetic distance is 0.003 9 and 0.004 0, the genetic similarity coefficient is 0.996 1 and 0.996 0 between Angora goats and F₃ and H generation. DNA fingerprinting technique as molecular genetic marker was also used in the research. The results revealed the similarity coefficient in different populations in Angora goats, F₂， F₃, and H generations were 0.454 0, 0.407 6, 0.611 3 and 0.610 9 respectively, which reached marked difference level between Angora goats with F3 and H generations(P＜0.01). The results of biochemical level and molecular level supported that cross breeding should be applied in F₂ and F₃ generation.

In this study, the genetic variation of porcine heart fatty acidbinding protein(HFABP) gene was detected by PCR-RFLP with HinfⅠ and HaeⅢ in 77 pigs of Zhongxu Black Line I. Meanwhile, effects of different PCRRFLP genotypes of H-FABP gene on main growth traits were analyzed in order to investigate whether they have unfavorable effects on growth traits or not during making meat qualities assistant selection by H-FABP gene. The results showed three variant restriction sites of porcine HFABP gene including HinfⅠ-RFLP in 5′-upstream, HaeⅢ-RFLP and HinfⅠ*-RFLP in intron 2, were conformed by PCR-RFLP method. Statistic significant difference(P＜0.05) of product performance (weight of 170 days) was found among animals grouped by different genotype at the HinfⅠ-RFLP site, while groups divided by any other genotypes had no significant differences among all product performance. Conclusion made in this paper will contribute to molecular assistant selection of economic traits including meat quality and production performance in pig breeding.

Fibroblasts were isolated from adult mouse lip skin and cultured，and then starved 1 week with 0.5% FBS media before used as donor cells. In addition, adult female mice were superovulated with PMSG and hCG, and their eggs were taken as recipients. Embryos reconstructed were activated 6 hours with 10 mmol/L SrCl₂ 2 hours after injected nucleus, and then cocultured with mouse oviduct epidermal cells, adding M16 media modified. When being in the stage of blastocyst, they were transfered on the feeder layers of mouse embryonic fibroblasts, adding rat cardiomyocyte media conditioned. After hatched from blastocysts, ICM were isolated and trypsinized, and then co-cultured continuously to gain ES cell masses. Results indicated that 2-cell rate of embryos reconstructed with fibroblasts was 54.05%, development rate of morula was 17.14%, blastocyst rate was 6.90%. Under the same circumstance, 2-cell rate of embryos reconstructed with cumulus cells was 60.00%, development rate of morula was 21.85%, blastocyst rate was 11.69 %, but developmental capacity of embryo reconstructed was no difference between two donor cells. ES cell -like colonies were isolated from 6 blastocysts with fibroblasts, in which 3 ES cell-like colonies could be passaged and cultured successfully. In control group ES cell-like colonies were harvested from 9 blastocysts, in which 5 ES cell-like colonies could be passaged successfully. ES cells isolated were island-like, positive by AKP staining, and could spontaneously differentiate into epidermal or shuttle-like cells around them in vitro. After routinely frozen and thawed, they were with characteristics of ES cell.

This study explored active immunization against cholecystokinin in laying hens and the effect on nutrition and physiology. The antibody titers of serum and yolk were examined by ELISA. The performance, nutrient digestibility，the development of pancreas and gallbladder, the activity of trypsin and the level of hormones after immunization were examined. The result showed active immunization against cholecystokinin resulted in development of high antibody titers in serum and yolk,decreased the level of cholecystokinin in blood.After the first booster injection, the antibody titers almost reached peak level.The development of gallbladder and pancreas were not affected by CCK immunization. The specific activity of pancreassecreted enzymes was increased in treated group (CCK). Active immunization had no effect on growth hormone, insulin and leptin in serum. The performance of layers was not affected by CCK immunization. It is concluded that active immunization against cholecystokinin in laying hens has no negative impact on the physiology of hens and results in the production of eggyolk with high content of CCK antibody.

Effects of forage to concentrate ratio on dynamic changes of pH, NH₃-N concentration, VFA pattern of rumen fermentation were studied. Four Holstein cows with rumenal cannula in mid lactation were used in 4×4 Latin square design experiment with 23 d each period. Dietary forage to concentrate ratios were 30∶70CW(forage was composed of Chinese wildrye,CW), 30∶70CCA（forage was composed of corn silage, Chinese wildrye and alfalfa, blend）, 50∶50CCA and 65∶35CCA, respectively. The results indicated there were significant changes in pH value and ammonia N concentration (P＜0.05), acetate tended to be higher in 30∶70CW (P=0.10), acetate to propionate ratio and butyrate concentration in the rumen were significantly different (P＜0.01). Milk fat percentages were significant different (P＜0.01), highest in 30∶70（blend）; Milk yield, protein percentages, and solid nonfat (SNF) contents were significantly different (P＜0.01).

1 188 hatching eggs were put randomly in 6 incubator trays for incubation. Each tray was a trial replication. Samples were collected at Day 6, 9, 12, 15, 18 and 21 of incubation to determine albumen glucose content; weight, moisture, protein, fat content of embryo; weight, moisture, fat content of liver; and lipid, fatty acids content, weight of yolk sac. The results showed that liver fat content increased and embryo moisture, albumen glucose content, yolk sac weight decreased with hating days increasing. Embryo fat and protein content were changeable in incubation period, the former was the lowest at Day 12 of incubation， the latter was higher in Day 6, 12, 15 of incubation. Relative liver weight was positively correlated to liver moisture content throughout incubation, positively and negatively correlated respectively with yolk palmitic acid and oleic acid at Day 15 of incubation. Yolk stearic acid content was negatively correlated to linoleic acid at Day 6 and oleic acid at Day 12, but positively correlated to arachidonic acid at Day 6 and Day 15 of incubation.

The full-length genome of PRRSV HB-2(sh)/2002 was sequenced and analyzed. The size of the virus genome was 15 373 nucleotides, excluding the poly(A)tail. Comparative analysis with the genomic sequences of domestic and abroad North American isolates showed that HB2(sh)/2002 shared 88.7%~95.1% identity with them. The isolate was a mutant of PRRSV with unique deletion, namely a 36 nucleotides deletion in Nsp2 and 3 nucleotides deletion in GP3 were found. This is first finding that PRRSV exists deletion variation. Our results enrich information data of PRRSV genome and provide a valuable basis for further study of biological characteristics, heredity and mutation of PRRSV.

The APXⅣ gene, a recently discovered RTX determinant of Actinobacillus pleuropneumoniae, was shown to be species-specific. A pair of primers were designed for amplifying this 650 bp fragment in PCR experiments.The PCR products was labeled with digoxigenin as DNA probe for detection of Actinobacillus pleuropneumoniae.The hybridization assay results showed that the reference strains of the 12 serotypes of Actinobacillus pleuropneumoniae were positive, no cross-hybridization was detected with DNAs from other bacterial species closely related to A. pleuropneumoniae. The sensitivity result showed that as few as 10×10² of Actinobacillus pleuropneumoniae could be detected by DIG-labeled probe. The detection results for clinical sample tissues showed that Actinobacillus pleuropneumoniae could be found in tonsils ，trachea and lung .The high sensitivity and specificity of the DIG-labeled probe will make it useful in field diagnostic work and epidemic investigation.

With PCR and biochemical reaction test, sixty-six strains of Pasteurella multocida(Pm) was isolated from the lung tissues of pneumonic swine or nasal swabs of swine suffering progressive atrophic rhinitis(PAR) swine. Their medicine sensitivity was then studied. PCR assay was used to type these Pm isolates, as well as test the toxA gene. Guinea pig skin test and mouse lethal test were used to study the toxigenic pasteurella multocida (T⁺Pm). The results showed that all PCR positive strains were coincident with the biochemical reaction criteria of Pm. PCR typing assay indicated that forty-six strains were serogroup D, eighteen strains were serogroup A, one strain was serogroup B and one strain was untypable. Eight strains were identified as T⁺Pm by PCR method. Guinea pig skin test and mouse lethal test also confirmed that the eight isolates were T+Pm. All the eight T⁺Pm strains were serogroup D, and were isolated from the swines suffering severe PAR.

The Eperythrozoon suis genomic DNA was extracted from blood samples with Eperythrozoon infection based on the light and electron microscopic examinations. The 16S rRNA gene was amplified by using the universal eubacterial primers. The PCR product was cloned and sequenced. A sequence of 1 469 base-pair(bp) was obtained from each of the three naturally infected pigs at the different pig farm. Each of the three sequences was compared to that derived from GenBank using BLASTn, and the closest sequence was 16S rRNA gene of E. suis Illinois strain, with a similarity of 95%. These findings suggested that the E.suis isolated from pigs in Guangdong, China is a new genetype E. suis. The phylogenetic analysis based on the 16S rRNA genes sequences of E.suis Guangdong strain and other related organisms, including Eperythrozoon and Haemobartonella, some species of Mycoplasmatales and Rickettsiales in GenBank database, showed that all species in Eperythrozoon and haemobartonella formed a separate and distinct phylogenetic branch, these haemotrophic bacteria were more closely related to Mycoplasma spp.in Mycoplasmatales (75%)than to Anaplasma, Bartonella and Ehrlichia spp in Rickettsiales (70%). Our results indicated that Eperythrozoon and Haemobartonella genera should be reclassified in Mycoplasma genus of Mycoplasmatales to reflect their actual phylogenetic relations.

A line of Eimeria mitis with an abbreviated life cycle (i.e. a “precocious ” line) was derived from the Zhuozhou strain by repeated passage of the oocysts which were the first to be recovered from infections in chickens. The prepatent period was reduced by 19 hours. The precocious parasite is less pathogenic than the parent strain, has a reduced reproductive potential, and remains much of the immunogenicity of the parent strain. Shiqiza chicks inoculated with the parasites of the precocious line were well protected against challenge with the Zhuozhou strain. Through a relaxed selection of 10 passages, it was showed that the precocious line is genetically stable in its prepatent time, reproduction peak and potential, and pathogenicity.

The effect of BQ123,a selective ETA-receptor antagonist, on pulmonary vascular structural remodeling induced by low ambient temperature was investigated through observing the dynamic change of pulmonary arterioles medial thickness and pulmonary blood vessel endometry area caused by proliferous smooth muscle cells in broiler chickens. Two hundred 16-day old commercial broiler chickens were randomly divided into 4 groups as follows: 50 birds were exposed to normal temperature(20 ℃) and injected normal saline to abdominal cavity as control group, 50 birds were exposed to low temperature (7~9 ℃) and injected normal saline to abdominal cavity as low temperature group，50 birds were exposed to low temperature and injected low dose BQ123 to abdominal cavity as low dose BQ123 group，and 50 birds were exposed to low temperature and injected high dose BQ123 to abdominal cavity as high dose BQ123 group. Pulmonary arterial pressure (PAP ) was determined as index of pulmonary hypertension. The measurement of ratio of vessel wall area to vessel total area (WA/TA) and mean medial thickness in pulmonary arterioles (mMTPA) were accomplished by using the microscopic image analysis program. The results showed as follows,(1)BQ123 significantly inhibited the increase of mPAP(kPa): high dose BQ123 group was lower than low temperature group at 23 days(P＜0.05);high dose BQ123 group and low dose BQ123 group were obviously lower than low temperature group at 30 days(P＜0.01);(2)BQ123 inhibited the increase of WA/TA of pulmonary arterioles: the value of 30~50 μm pulmonary arterioles of low temperature group was obviously higher than that of low dose BQ123 group and high dose BQ123 group (P＜0.01); It bears an analogy to the differences between groups in the other ranks of pulmonary arterioles;(3)BQ123 made mMTPA of pulmonary arterioles to be reduced: to 30~50 μm pulmonary arterioles,at the age of 23, low temperature group was obviously higher than low dose BQ123 group and high dose BQ123 group(P＜0.01); at the age of 30, low temperatue group was higher than low dose BQ123 group(P＜0.05) and obviously higher than high dose BQ123(P＜0.01), and low dose BQ123 was higher than high dose BQ123(P＜0.05);It bears an analogy to the differences between groups in less than 30 μm pulmonary arterioles; It was not obviously different between groups to 50~120 μm pulmonary arterioles. It can be concluded that BQ123 can inhibit pulmonary vascular structural remodeling and pulmonary artery hypertension induced by low ambient temperature in broiler chickens. ET may play a key role in pulmonary vascular structural remodeling and pulmonary artery hypertension induced by low ambient temperature in broiler chickens.

The microstructure and ultrastructure of genita tract mucosa in sow were observed by histological method and electron microscopic technique. Twenty sows of Landrace× Yorkshire two-way crossbred were selected . The tissue structure of oviduct, uterus and vagina mucosa in sow were respectively observed by transmission electron microscopy(SEM) and light microscopy(LM). The results showed that the genital tract mucosa was composed of epithelia, lamina propria and muscularis mucosa. The cilium and microvilli were observed on the simple columnar epithelium in oviduct and uterus. Some lymphocytes were found in the epithelia and lamina propria, and passed through the epithelia and arrived the epithelial surface. The pseudopod of lymphocytoplasm were jutted out. The mitochondria and Golgi complex were rich in the lymphocytoplasm. Lymphocyte aggregation of genital mucosa were formed in the stroma， lymphocytes in cervix mucosa arrived to the epithelial surface, like the phenomenon “lumen excretion” . Our studies revealed that genital mucosa in sow may be the induce site of mucosal immune, since numerous lymphocytes distributed in it.

This study was carried out to investigate the mechanism of signal transduction in murine immunocytes induced by polysaccharide from Astragalus membranaceus. Nitric oxide (NO) concentrations of murine peritoneal macrophages were examined by a spectrophotometric assay based on the Griess reaction; cytoplasmic free Ca²⁺ in murine splenic lymphocytes was measured by a spectroflurometer assay with probe of Fura2-AM. A new ion-pair reversed phase performance liquid chromatograph was used to determine protein kinase C (PKC) activity of spleen lymphocytes in mice. The results showed Astragalus membranaceus polysaccharide increased the production of NO of macrophages and the concentration of intracellular free calcium in splenic cells and activated the PKC of spleen lymphocytes in vitro in mice. In conclusion, Astragalus membranaceus polysaccharide might perform its immunoregulation functions via signal transduction system in immunocytes by activating immunocytes to release NO so as to modulate level of intracellular free calcium and raise the activity of PKC.

In this paper, the mechanism of action of the four Chinese herbal medicines, which are Isatis leaf, Isatis root, Forsythia fruit, Patrinia and their complex prescription on Escherichia coliinduced diarrhea of piglet, was preliminarily studied from the aspects including the bacteriostatic activity in vitro on E.coli, the antagonism against liquid retention mediated by E.coli heatlabile enterotoxin ( LT )， the antagonistic effect on diarrhea induced by castor oil, the reducing action on inflammatory exudation and the inhibiting effect on fast intestinal movement. The results showed that Isatis root, Forsythia fruit, Patrinia and their complex prescription all had more or less bacteriostasis on E.coli O149K88. Escherichia coli was cultured in bacterial culture medium which the extracts of the Chinese herbal medicines were added, and the cultural product LT was used to do experiment in ligated rabbit ileum. They all significantly or very significantly reduced the liquid retention caused by cultural supernatant fluid in ligated loops (P＜0.05，P＜0.01). When the extracts of Patrinia and LT were directly injected into ligated loops together, the liquid retention was significantly reduced (P＜0.05). Complex prescription significantly or very significantly reduced incidence and frequency of diarrhea induced by castor oil in mice (P＜0.05，P＜0.01). Isatis root very significantly inhibited the rate of mouse’s intestinal movement (P＜0.01). Patrinia, Isatis root and complex prescription also significantly or very significantly inhibited exudation of dyestuff induced by acetic acid in mouse’s abdominal cavity (P＜0.05，P＜0.01). The aforementioned results indicated that the bacteriostatic activity, the antagonism against diarrhea caused by enterotoxin LT, the antagonistic effect on diarrhea induced by medicine, the reducing action on inflammatory exudation and inhibiting effect on fast intestinal movement were important mechanism of Chinese herbal medicines on Escherichia coliinduced diarrhea of piglet. The results provided an important theoretical basis for clinical use of Chinese herbal medicines to Escherichia coliinduced diarrhea of piglet.

Experiments to investigate the effects of daidzein on membrane digestion of disaccharide in suckling and weanling piglet were carried in vitro. 12 piglets were randomly assigned two groups， either supplemented with 20mg/kg·BW daidzein or skim milk powder once per two days after birth one week. 14 and 35 days old piglets were killed, jejunum and colon were collected for further study.The result showed that supplemented with daidzein can improve the activities of maltase and lactase in jejunum mucosa and colon mucosa in the lactational period of piglet, the activities of maltase and lactase in jejunum mucosa increased by 63.30%（P＜0.01）and 49.98%（P＜0.01）, and those in the colon increased by 56.78%（P＜0.01）and 24.05%（P＜0.01）respectively. However, in weanling piglets the activity of lactase was decreased by 41.40%（P＜0.05），whereas the activity of maltase increased by 22.31%（P＜0.01） in jejunum, the activity of maltase increased by 21.14%（P＜0.05）in colon. This result indicates that feeding daidzein can improve the using of disaccharide in piglets.

Lipoprotein lipase (LPL) gene is a multifunctional protein, playing a major role in the hydrolysis of triglycerides in chylomicrons and very low density lipoproteins (VLDL). According to cDNA of Landrace breed （GenBank accession: X62984）, a pair of primers was designed for amplification of intron 3. Sequencing analysis indicated that a G1200A exits in Large White breed by cloning and sequencing. The mutation can be detected by PCR-EcoT22I-RFLP. Polymorphism analysis in a resource family showed that significant difference exits in carcass traits. Pigs with AA genotype had more 6th-7th rib fat thickness (13%,P＜0.05), thorax-waist-fat thickness (11.7%,P=0.065 3), buttock fat thickness (13.1%,P=0.073 0) and average fat thickness (10.4%,P=0.050 3) than pigs with BB genotype. LPL gene showed mainly in the pattern of additive effect and all the dominant effect were not significant. The value of additive effect of 6th-7th rib fat thickness, buttock fat thickness and average fat thickness was -0.17±0.07（P＜0.05）,-0.12±0.06（ P＜0.05）,-0.12±0.06（P＜0.05）,respectively. The allelic frequency is significantly different between indigenous Chinese breeds and European breeds.

According to the published nucleotide sequences of the VP1 gene of footandmouth disease virus serotype Asia 1 isolates, a pair of primers were designed and synthesized to clone the VP1 gene of YNBS/58 strain. PCR product was cloned into pProexHTb vector, and E.coli BL21 was transformed by the recombinant plasmid pProex-VP1 for sequencing and expression .The expressed product was identified by SDS-PAGE and Western blot, and purified by Ni-NTA His.Bind resins. The results showed that the nucleotide sequence identity of VP1 gene between YNBS/58 and India93, India 97,India99, Iseral and YNAs11 strains is from 80.3% to 97.5% and amino acid identity is from 85.8% to 96.5%, the recombinant VP1 protein was significant at 34 ku by SDS-PAGE and Western blot, which accounted for 30% of total protein in E.coli lysates,and the recombinant protein was purified successfully.

In this study, the genes encoding main structural proteins and 3′ untranslated region (UTR) of a commercial domestic vaccine strain H52 and a commercial foreign vaccine strain H52 of infectious bronchitis virus (IBV) were obtained by RT-PCR, then were cloned and sequenced respectively. The sequence analyses showed the genetic information of S1 gene, M gene, N gene and 3′UTR of domestic vaccine strain H52 was remarkably different from that of foreign H52 strain and that of published sequences of H52 strain. Compared with foreign H52 strain, this domestic H52 strain was genetically closer with M41 strain and was located in the same branch of phylogenetic tree based on the sequences of main structural protein genes. The results strongly suggested that it was necessary to build genetic information archives of seed stock of IBV vaccine strains.

Liver material of a dead giant panda and different generations of CCV DXMV strain isolated from it were used to amplify partial spike protein gene of canine coronavirus by nested PCR with primers of CCVF1,CCVR1 and CCVF2,CCVR2. 1 086 bp and 515 bp nucleotide sequences were acquired respectively. The fragments were purified, sequenced and analyzed with the software of DNASTAR and DNASIS. The results showed that the sequences amplified from the giant panda liver and 2,3,29 generations of CCV DXMV between primers of CCVF2 and CCVR2 were identical and suggested that the virus was successfully isolated from the giant panda liver. 1 047 bp nucleotides between primers of CCVF1 and CCVR1 were correctly sequenced from the 3rd generation of CCV DXMV and its homology with other CCV strains were 83.3%~100%, especially 100% with the CCV NVSL strain that isolated from USA.