Three hundred and one piglets of Suzh ong line 1 and 2 were chosen for halothane test(HT), with the halothane positive rate of 1.33%. 34 halothane negative(HN) piglets were randomly selected for gen otype testing and 6 of them were found to be heterozygous. The results showed th at genotype frequencies of HalNN, HalNnand Halnn w ere 81.26 %, 17.4% and 1.33%, respectively, while the frequencies of N gene and n gene wer e 89.97% and 10.03%, separately. 4 pigs with genotype Halnn gave worst meat quality appearing 3 typical and 1 slight PSE meat. Pigs with genotype Hal N Nor HalNndid not show PSE meat. 208 offspring from 20 HN sows mat ed wit h halothane positive(HP) boars, 21 piglets from 4 litters were HP, with low dail y gain, low feed efficiency and bad meat quality but high dressing percentage, l arge loin-eye area and high lean meat percentage.

In order to screen antigenic genes of Clonorchis sinensis (C.sinensis).Firstly,a cDNA expression library from adult worms of C.sinensis was successfully constructed with lambda ZAP express vector.Total RNA of C.sinensis adult worms were extracted by the Trizol reagent and mRNA were further purified through oligo-dT cellulose.The first strand eDNA was synthesized by using MMLV reverse transcriptase.After the synthesis of the second strand,the cDNA were purified by CHROMA SPIN-400 kit and then ligated with lambda ZAP express vector,then packaged in vitro and amplified.The original library contained 1.5 × 106 pfu cDNA clones,the titer of amplified library reached 1.5 × 1010 pfu/mL,in which about 99% clones were recombinants and most of insert DNA fragments were 0.4-2.0 kb.Secondly,immunoscreened using the naturely infected man serum from C.sinensis.The positive clones were sequenced and analyzed.From 2.0 × 105 recombinant clones of the eDNA library,41 positive clones were obtained.Sequence analysis indicated that the cDNAs encoded proteins including glycine rich antigen 2,proline rich antigen 2 and antigen Cs44 from C.sinensis,anothers were lower similarity to predicted protein from Nematostella vectensis,transcription elongation factor GreA from Bartonella quintana str.Toulouse and NM_132090 CG3446 gene product in Drosophila melanogaster from Schistosoma japonicum.These data may form a foundation for identifying recombinant antigens that can be used in the diagnosis or vaccination against clonorchiasis.

The σC gene of ARV S1133 was designed to amplify by reverse transcription chain reaction(RTPCR).The σC gene was inserted into the vector pMD19-T,identified by PCR method and restriction enzyme,and sequenced.It showed that the insert cloned gene fragment was the σC gene of ARV.Then the gene was inserted intc the pET32a(+) and indicated that fusion expression vector pET32a-σC was constructed.The recombinant fusion protein was highly expressed in E.coli BL21 induced by 1.0 mmol/L IPTG for 5 hours in the form of inclusion bodies.The weight of recombinant fusion protein molecular is 54 000.Western-blot with ARV antibodies against the fusion protein showed the recombinant protein has a favourable reactivity.

The levels of the antibody response against,classic swine fever (CSF) vaccine were measured by blocking ELISA at different time for pigs vaccinated with CSF vaccine (CSFV group,n= 3),pigs inoculated with porcine eircovirus type 2 (PCV2) and with CSF vaccine two weeks later (when PCV2 viremia was detected by PCR,PCV2/CSFV group,n=3),or inoculated with both CSF vaccine and PCV2 at the same time (CSFV/PCV2 group,n=3),respectively.And distribution of genome or antibodies specific to PCV2 of the PCV2 infection group,PCV2/CSFV group and CSFV/PCV2 group were also detected by indirect ELISA or PCR,respectively.The results showed that experimental infection of PCV2 was successful.In pigs inoculated with both PCV2 and CSF vaccine,the antibody response to CSF vaccine was significantly lower than that of animals treated with CSF vaccine vaccination alone at 52 days postinoculation (DPI).The average titers of antibodies against CSFV in animals of CSFV group were obviously higher than those of the PCV2/CSFV or CSFV/PCV2 group at 49 and 52DPI,respectively.The positive rate of antibodies against CSFV in pigs of CSFV group was 100% in comparison with that of animals inoculated with PCV2 and the vaccine (only 67%).The results suggested that the infection of PCV2 could suppress the antibody response to classical swine fever vaccine.

The amplified VP2 gene (PPV strain SC-1) and PCV20RF2 gene were inserted into the eukaryotic expression vector pPI-2.EGFP.Then the recombinant plasmid named pPI-2.EGFP.VP2.ORF2 was obtained.Mediated by liposome,the recombinant plasmid was transfected into Veto cells and expressed.Using immunofluorescence assay,the fluorescence of expression products were first detected at 20 h after transfection and peaked 36 h.Under electronmicroscope,virus-like particles (VLPs) can be observed in the transfected cells.To confirm the obtained VLPs to be recombinant particles,piglets were immunized using purified VLPs.The dynamic variation of blood T lymphocytes and serum antibody level of PPV and PCV2 were measured.The results showed that the ratio of CD3+,CD4+ T lymphocyte in peripheral blood lymphocyte of immunized piglets raised in a certain degree,the number of CD8+ T lymphocytes fell at 7-14 d after immunization,and then raised.Relatively high level of PP-V,PCV2 specific antibody could be detected.This indicated that the expression of recombinant plasmid pPI-2.EGFP.VP2.ORF2 was successful,the virus-like particles were formed and showed favourable immunogenicity.

Two recombinant plasmids pVAX/Sj23 and pVAX/mIL-18 containing Schistosoma japonicum 23 000 membrane protein (Sj23) and murine IL-18 were evaluated for their ability to induce immune responses and to protect against S. japonicum challenge in mice. All animals vaccinated with pVAX/Sj23 alone or plus pVAX/mIL-18 developed specific anti-SWAP (soluble worm antigen preparation) ELISA antibody and splenocyte proliferation response,and co-injection of pVAX/mIL-18 significantly increased the production of IFN-γ and IL-2 compared with pVAX/Sj23 alone, indicating that IL-18 enhances the Th1-dominant immune response. The challenge experiment showed that worm reduction rates in pVAX/Sj23 group compared with control group (pVAX1) was 26.5% and in the pVAX/Sj23 plus pVAX/mIL-18 group was 41.9% ,and the hepatic egg reduction rates were 42.7 and 49.6%,respectively. These results indicated that co-injection of an IL-18 plasmid with Sj23 DNA vaccine efficiently improves the protective effect against S. japonicum infection.

The rabbit enteropathogenic E. coli (rEPEC) strain RDEC-1 possesses a lifA homologue adjacent to the LEE pathogenicity island. To study the entire nucleotide sequence and biological function of lifA,the DNA sequence and biological function of RDEC-1 lifA were analysed with gene cloning,gene knock-out and in vivo virulence examination. The result showed that the entire coding sequence of the lifA of RDEC-1 shares nearly absolute homology with the lifA of human isolates. RDEC-1 lifA inhibited IL-2 expression in stimulated rabbit peripheral blood mononuclear cells. We further demonstrated significant reduction in fecal bacterial shedding by RDEC-1 derivative lifA mutant when compared with its parent strain. In a competitive study when rabbits were inoculated with a combination of the WT and the mutant, the WT was the predominant bacteria recovered from fecal samples, while fewer mutant bacteria were recovered. However,the lifA mutant is able to induce A/E type of lesions as efficient as the parent strain. The data provide direct evidence that lifA of rEPEC plays a role in immunomodulation and in in vivo colonization in the intestinal tract.

To investigate the effect of the disequilibrium of calcium homeostasis on the apoptosis of MDCC-MSB1 cells induced by lanthanum chloride(LaCl3 ), MDCC-MSB1 cells was conventionally cultured in RPMI1640, which was tured for 24 h, MTT was utilized to detect the cell multiplication inhibition ratio,DNA ladder and TUNEL to detect apoptosis,the Fura-2/AM as the probe to detect the [Ca2+]i within cells. The results indicated when LaCl3 concen and [Ca2+]i also increased,and presented a dose-effectiveness relationship. LaCl3 could restrain the proliferation of MDCC-MSB1 cells,suggesting their apoptosis induced by changing [Ca2+]i.

To explore the effects of long-term treatment of different dietary energy levels on ovarian expression of mRNAs for LHR and FSHR,the present study was performed in nine growth-matched littermate crossbred (Land-race×Large White X Duroc) prepubertal gilts. At approximately 30 kg of body weight and 50 day of age,gilts were housed with individual feeding stalls and placed on a normal level of feeding for 90 days (dl-90) with free ac-cess to water and food throughout the whole research. From d91 ,littermates were divided and randomly assigned to one of the following three treatment lines for 3 weeks till d112:Group H,Group M, and Group L, fed the high energy level diet (n = 3, digestible energy 14.87 MJ/kg), moderate energy level diet (n = 3, digestible energy 12.39 MJ/ kg), and low energy level diet (n = 3, digestible energy 9.98 MJ/kg), respectively. When gilts were slaughtered on d112 after 3 weeks energy treatment, both ovaries of every gilts were collected,snap frozen in liquid nitrogen and re-tained at -80℃ for use to determine and analysis the relative amount of ovarian LHR and FSHR mRNAs using semi-quantitative RT-PCR. Results showed that the effect of dietary energy treatment was notable: the ovarian ex-pression of mRNAs for LHR and FSHR was significantly higher (P<0.05) in gilts treated with high energy diet compared to gilts treated with moderate and low energy diets, while gilts treated with low energy diet had a signifi-cantly lower (P<0.05) ovarian LHR and FSHR expression compared with gilts treated with moderate and high en-ergy diets. These results revealed that ovarian expression of I.HR and FSHR in prepubertal gilts increased as the lev-el of dietary energy intake elevated,i, e. , high energy diet can markedly enhance ovarian expression of mRNAs for LHR and FSHR,whereas energy deficit markedly suppress the expression.

The expression patterns of 5-hydroxytryptamine(5-HT),gastrin(Gas),β-endorphin(End),somatostatin(SS),vasoactive intestinal peptide(VIP),glucagon(Glu) and neuropeptide Y(NPY)-positive cells in the duck thymus were studied by the immunohistochemical method associated with image analysis.The result shows that these 7 kinds of neuroendocrine cells with strong intensity were differentially detected in the duck thymus.The End-positive cells were abundantly expressed in the thymic cortex,whereas the Gas,5-HT,SS,VIP,Glu and NPY ones were more frequent in the medullary and around the corticomedullary junction.Except Glu,the other 6 kinds of neuroendocrine substances with various intensity were expressed in the cells of thymic corpuscles.The observation demonstrated that the duck thymus is not only a primary lymphatic organ,but also has important neuroendocrine functions.The End-positive cells in the thymus may play crucial roles in the development of immature T-lymphocytes.The neuroendocrine cells with a predominant distribution in the medulla and around the corticomedullary junction might facilitate exerting their influence via an endocrine,autocrine or paracrine pathways on the function of mature T-cells.The possible roles of thymic corpuscles are also discussed.