Abstract:The somatic cells can be induced into ES-like stem cells when retrovirally infected the defined transcription factors including Oct4, Sox2, Klf4 and c-Myc. These ES-like cells are named induced pluripotent stem (iPS) cells and this method is called iPS technology. Until the end of 2009, iPS cell lines have been generated in various animal species, such as mouse, human, rhesus monkey, rat and pig. Mouse iPS cells are also used to generate chimera mice and viable mice through the tetraploid complementation. Although iPS cells are extremely similar to ES cells in both morphology and growth features, to generate iPS cells do need the defined culture procedures. Based on the update global iPS technology development and the iPS studies in our laboratory, this paper focused on the establishment of iPS cell lines and improvement of iPS cell culture condition.

Abstract:Hepatitis B virus core (HBc) proteins have been used as carrier for foreign epitopes since the 1980s. They could self-assemble into icosahedral particles. Foreign epitopes could be inserted into HBc protein in various protein regions, including the N- or C-terminal and the major immunodominant region (MIR). The factors relevant in the design of HBc particles for vaccine purpose are summarized in this review.

Abstract:In order to ensure the biosafty of the IFN-γ antiviral activity assay, we used a replication-deficient VSV carrying GFP as an interferon sensitive indicator virus (VSV△G*G). The antiviral activities of porcine IFN-γ expressed in Escherichia coli and in baculovirus on MDBK cells were assessed. The results showed that the antiviral activity of porcine IFN-γ expressed in baculovirus could reach 105 IU/mL, while the porcine IFN-γ expressed in E. coli showed some antiviral activity (32 IU/mL) after refolding. The results of the VSV△G*G-based antiviral assay were almost identical to that of the VSV*GFP-based assay, suggesting it is highly feasible to use VSV△G*G as a substitute for VSV*GFP, making assays for IFN-γ antiviral activity safer and more accurate.

Abstract:In order to construct the recombinant retrovirus vector of human ngn3 gene and its packaging cell line, we successfully amplified the open reading frame (ORF) of ngn3 gene from human fetal pancreatic tissue by RT-PCR. The PCR products of human ngn3 gene was subcloned into pMD18-T vectors and sequenced. Results showed that its sequence was fully consistent with the ngn3 gene published in GenBank(GenBank Accession No. BC126468). The correct fragment was digested by EcoR I and Hpa I from recombinant pMD18-T vector and inserted into the same restriction enzyme sites of retroviral vector pMSCV-neo. We got recombinant retrovirus vector pMSCV-ngn3, which was identified by double restriction enzyme digestion and then transfected into PT67 cells by lipofectamine 2000. We established the PT67-ngn3 packaging cell line by G418 selection, which was detected by RT-PCR and immunohistochemistry staining. The detection results showed that the Ngn3 expressed at the mRNA and protein level in the packaging cell line. RT-PCR detection and electronic microscope analysis showed that the recombinant retroviral vector pMSCV-ngn3 was packaged into infectious virus particles and released into the supernatant of the cells. These results demonstrated that a PT67-ngn3 packaging cell line was successfully established, and this could facilitate the study of differentiation of the human fetal pancreatic progenitor cells into insulin-producing cells by using the ngn3 gene.

Abstract:VP1 is a major antigenic protein of foot-and-mouth disease virus(FMDV), which induces the immune response against FMDV infection, and contains several epitopes of the virus. we designed and chemically synthesized a DNA fragment which encoding a tandem repeat protein of 136?160aa and 198?211aa of a strain of type Asia I FMDV, and cloned the gene of heavy chain constant region of sheep IgG. By using the BamH I, EcoR I and Xho I sites, both genes were cloned into pPROExHTb vector in turn to form a recombinant plasmid pPRO-FshIgG. A chimeric protein, named FshIgG, was obtained after transforming the pPRO-FshIgG into Escherichia coli BL21 (DE3) host cell and induced by IPTG. Inoculation with 100 μg FsIgG induced strong neutralizing antibody response in guinea pigs, and FshIgG inoculated guinea pigs were also protected against 200 ID50 FMDV challenge. Our study indicated that the heavy chain constant region of sheep IgG can act as the carrier protein for FMDV peptide epitopes, and FshIgG is a potential multiepitope peptide vaccine candidate to prevent FMDV infection.

Abstract:In order to construct recombinant adenovirus vector expressing Suppressor of cytokine signaling 3 (SOCS3) and obtain infectious adenoviral particles, SOCS3 gene was amplified from plasmid pcDNA3-SOCS3 and subcloned into the adenovirus shuttle plasmid pAdTrack-CMV. After sequence confirmation, the recombinant shuttle plasmid pAdTrack-CMV-SOCS3 was linearized by Pme I, and then transformed into BJ5183 competent cell, the recombinant plasmid pAd-SOCS3 was obtained by homologous recombination between pAdTrack-CMV-SOCS3 and the adenoviral backbone plasmid pAdEasy-1 in BJ5183. The pAd-SOCS3 was linearized by Pac I and transfected into HEK293 cells via liposome. The recombinant adenovirus was packaged and amplified in HEK293 cells. After purifying, virus titer was determined by tissue culture infectious dose 50 (TCID50). Using the recombinant adenoviruses to infect porcine primary adipocytes, the expression of green fluorescent protein (GFP) was observed by fluorescent microscopy, and SOCS3 gene was identified by RT-PCR and Western blotting. Restriction enzyme and PCR analysis demonstrated that the recombinant adenovirus vector was constructed correctly, and the virus titer reached 1.2×109 PFU/mL. The result of RT-PCR and Western blotting showed that SOCS3 mRNA and protein expression was remarkably increased in porcine primary adipocytes infected with recombinant adenovirus. In conclusion, this study successfully constructed the recombinant adenovirus containing SOCS3 gene, and can be helpful for further research on the function of SOCS3.

Abstract:To clone and express the gene encoding chicken aminopeptidase N (chAPN), and analysis the biological function of chAPN expressed in Escherichia coli (E. coli). The chAPN gene was amplified by RT-PCR from the kidney cells of chicken embryo and then cloned into the prokaryotic expression vector pCOLD-TF. Recombinant expression plasmid of pCOLD-TF-chAPN was constructed and then transformed into the competent E. coli BL21(DE3) cells for expression under different conditions such as induction time and inductor concentrations. Purified soluble recombinant chAPN was obtained by Ni-NTA His Bind Resin affinity chromatography and identified by SDS-PAGE gel and Western blotting assay. Its biological function was detected by its reaction with Leu-PNA and Enzyme-Linked Immunosorbent Assay (ELISA). The results showed that the expression product of chAPN gene in E. coli was soluble. It was able to bind infectious bronchitis virus (IBV) dose-dependently. In conclusion, chAPN gene has been successfully cloned and expressed in E. coli, which will establish a basis for further research the enzymatic activity and antiviral function.

Abstract:In order to research immunogenicity of the recombinant rVP2-IL-2 fusion protein, we obtained the rVP2-IL-2 fusion protein using Pichia pastoris expression system, and then evaluated its potential to induce immune responses in chicken. The effect was determined in the form of protective anti-IBDV VP2 titers, antibodies (IgG1 and IgG2a), lymphocyte proliferation, the levels of interferon-γ and interleukin-4 cytokines, and challenge experiment. Antibody titers and proliferation lymphocyte level suggested that the fusion protein could elicit specific humoral immune and cellular immune responses. antibody sub-type results indicated that the rVP2-IL-2 fusion protein induced secretion both of IgG1 and IgG2a. The seem result elicited from cytokines ELISA test, secretion of both of Th1 (?-IFN) and Th2 (IL-4) were induced by the rVP2-IL-2 fusion protein. Challenge experiment result shown that chicken immunized the rVP2-IL-2 fusion protein obtained 85% protection. These results confirm that the fusion protein enhances the protection against IBDV through both humoral and cell-mediated immunity, and thus could serve as a candidate for the development of IBDV subunit vaccine.

Abstract:We analyzed the microbial diversity and quantity of nitrifying bacteria in the enrichment reactor by Terminal Restriction Fragment Length Polymorphism (T_RFLP), a cultured-independent molecular technique. The result indicated that nitrobacteria enriched the best, and the diversity index decreased 62.80% compared with the initial data. Nitrobacteria were predominant in the reactor. Meanwhile, we studied the microbial diversity before and after adding Nitrobacteria into shrimp ponds, and analyzed several major bacterial species that existed stably in the pond. According to the analysis by T_RFLP program, species including Brevibacillus brevis, Microbacterium lactium, Azoarcus indigens and Bordetella holmesii were the dominant bacteria in the ponds.

Abstract:We studied the hydrogen evolution (HE) of green alga Chlorella pyrenoidosa grown in normal (nutrients sufficient) media and nitrogen, manganese or sulfur deprived medium. The results showed that photo-hydrogen evolution could occur under all conditions hereinbefore, but the efficiency of HE was maximum under nitrogen deprivation, and the total hydrogen yield was 88.613 μL H2/mg Chla, which was 4.61, 1.92, 3.63 times of control, manganese deprivation, sulfur deprivation groups, respectively. We also measured the growth, the photosynthesis and respiration of the alga. The data demonstrated that manganese deprivation had less influence than nitrogen and sulfur deprivation on the growth, the photosynthesis and respiration of C. pyrenoidosa. Compared with the normal (nutrients sufficient), manganese and sulfur deprivation inhibited the photosynthesis and growth of the alga while bringing small impact on respiration. Nitrogen deprivation, however, greatly restrained the photosynthesis and growth while enhancing the respiration. Those data provide clues for the further study on both the conditions optimization and mechanism of hydrogen evolution.

Abstract:Carboxyl-terminal processing protease of D1 protein (CtpA) catalyzes carboxyl terminal processing of the D1 protein of photosystem II, which is essential for the assembly of a manganese cluster and consequent light-mediated water oxidation. It is a target for the discovery of wide-spectrum herbicide. We amplified the CtpA gene from spinach cDNA with standard PCR method and constructed it into pET-28a vector to generate a recombinant expression plasmid. Recombinant CtpA fusion protein with His-tag was expressed as soluble protein in Escherichia coli BL21(DE3) after induction with 0.1 mmol/L IPTG at 8°C for 72 h. We purified the CtpA protein with the Ni-NTA affinity chromatography and Superdex 75 gel filtration chromatography respectively, and verified the protein by SDS-PAGE and Western blotting with anti-his antibody. Hydrolysis activity of CtpA was assayed by HPLC method with a synthetic 24-mer oligopeptide corresponding to carboxyl terminal of precursor D1 protein, and gave a total activity of 1.10 nmol/(mg?min). We used the purified CtpA protein as antigen to immune rabbit for the production of polyclonal antibody, and prepared antibody with high specificity and sensitivity. The results obtained in this paper provided the feasibility of high-throughput screening of lead compounds for the protease as inhibitors and mechanism analysis of CtpA enzyme.

Abstract:In this study, we analyzed the kinetics of bioconversion of conjugated linoleic acid (CLA) by permeabilized Lactobacillus acidophilus cells. The effects of cell mass, linoleic acid (LA) concentration, reaction pH and temperature on the bioconversion of CLA by permeabilized cells were investigated and the model system of bioconversion of CLA was established. The results showed that the production of CLA was increased by permeabilized cells. The optimal cell mass, pH and temperature of bioconversion of CLA were 10×1010 ufc/mL, 4.5 and 45°C, respectively. A marked LA inhibition phenomenon existed, and the early reaction rate of producing CLA reached the maximum (17.8 μg/mL?min) when LA concentration was 0.6 mg/mL. Michaelis constant was obtained by double-reciprocal plot and Hanes-Woolf plot. The reaction rate equation followed the classic Michaelis-Mentent equation at the low LA concentration, while there was a marked LA inhibition phenomenon at the high LA concentration. With the evaluated model parameters, the model system appeared to provide a description for the bioconversion of CLA by permeabilized Lactobacillus acidophilus cells.

Abstract:The 26S proteasome is a proteolytic complex responsible for the degradation of the vast majority of eukaryotic proteins. Regulated proteolysis by the proteasome is thought to influence cell cycle progression, transcriptional control, and other critical cellular processes. A novel Schistosoma japonicum gene (GenBank Accession No. AY813725) proteasome α2 subunit (SjPSMA2) was cloned. Sequence analysis revealed that the ORF of SjPSMA2 gene contains 708 nucleotides encoding 235 amino acids, and the molecular weight was estimated to be 25.84 kDa. Real-time PCR analysis showed that this gene expressed in 7 d, 13 d, 18 d, 23 d, 32 d and 42 d schistosoma. The mRNA level of SjPSMA2 was lower in 7 d and 23 d schistosomulum than that in other stages. The SjPSMA2 cDNA fragment was subcloned into an expression vector pET28a(+) and transformed into E. coli BL21 (DE3) cells. After induction with IPTG, the 30 kDa fusion protein was produced as included bodies. Western-blotting revealed that the fusion protein could be recognized by the rabbit serum anti-Schistosoma japonicum adult worm antigen preparation, and the protein in native could be detected. After immunization of BALB/c mice with the fusion protein, the reduction rates of worm counts and liver egg counts were 12.33% and 35.23%. ELISA results revealed that the vaccinated group showed a significant increase in the level of IgG antibody. This study provided an important basis for investigating the regulation mechanism of the proteasome during the development of Schistosoma japonnicum.

Abstract:LysinB (LysB) in mycobacteriophage D29 was cloned and expressed and its enzymatic properties were analysed. The lysB gene was amplified by PCR from mycobacteriophage D29 genomic DNA and inserted into pET22b vector. The constructed recombinant plasmid was transformed into Escherichia coli BL21(DE3) to express fusion protein, which was purified by Ni-NTA column and enzymatic activity detected. The results showed that expression plasmid pET22b-lysB was constructed successfully. Highly purified recombination protein (His-LysB) was obtained 33.2 mg from 1 L LB culture medium. A screening for His-LysB activity on esterase and lipase substrates confirmed the lipolytic activity. With p-nitrophenyl butyrate as substrate, the thermal stability of the enzyme was poor when the temperature was above 30°C. The enzyme exhibited higher stability at pH 5.0–9.5. The optimum temperature and pH for the lipolytic activity of His-LysB were 23°C and 7.5 respectively. Under the optimum conditions, the specific activity of His-LysB was 1.3 U/mg. Zn2+, Cu2+, Mg2+, Mn2+and phenylmethane sulfonyl fruoride severely inhibited the lipolytic activity of His-LysB. The result provides a new option for tuberculosis drug research and development.

Abstract:Lactoferrin in milk is a multifunctional protein. In addition, lactoferrin has antiviral, antifungal and antiparasitic activity. In this study, the N-terminus from porcine lactoferrin (PLF-N) was designed to express the antimicrobial action of recombinant porcine lactoferrin. We cloned a 1077 bp fragment of the PLF gene from mammary gland tissue of the lactating sow at the third day. Comparing nucleotide sequence with four strains of PLF gene published on GenBank, the homology was more than 99%. With the reference template of the cloned fragment of PLF-N and optimizing codon bias, we synthesized the gene of N-terminus encoding porcine lactoferrin (PLF-NS). The high expression gene of PLF-NS was cloned into the fusion expression vector pET30b and expressed in E. coli BL21 (DE3). After induced with Isopropyl β-D-1-Thiogalactopyranoside (IPTG), the target fusion protein was successfully expressed and identified in inclusion bodies by SDS-PAGE and Western blotting. The protein had a molecular weight of 42 kDa and accounted for 32% of the total cellular protein. After purification and renaturation, the purity of the expressed protein was 98%. The expressed PLF-NS protein showed obviously antibacterial activity. This method provides an excellent way for high expression of antimicrobial proteins when optimizing codon bias.

Abstract:We induced embryogenic calli (EC) and non-embryogenic calli (NEC) from flower filaments of Vitis vinifera L. cv. Chardonnay about 10 days before full bloom. The callus were sub-cultured, observed and verified by somatic embryo induction. PCR primers for VvSUC12 and VvSCU27 were designed according to the corresponding sequences in GenBank. After RNA extraction with RNAplant for EC and NEC cell lines, we synthesized the 1st strand DNA for semi quantitative RT-PCR, and normalized the density of the bands against house-keeping gene Actin. The results of 31 cycles semi-quantitative RT-PCR showed that VvSUC12 was highly expressed in both EC and NEC, with higher expression intensity in NEC than in EC, but not reached the significant level; while the expression of VvSUC27 was only detected in EC, and the expression level was significantly lower than that of VvSUC12. We increased the semi-quantitative RT-PCR cycle number to 35 and found that VvSUC27 gene was weakly expressed in NEC, in EC the intensity of the band was increased comparing with 31 cycles, and the expression level was higher than that of NEC. The paper discussed the differential expression of the two sucrose transporters and their relationship with the sucrose in the tissue culture medium.

Abstract:Cyanovirin-N (CVN) is an 11 kDa anti-HIV protein originally isolated from extracts of a cyanobacterium, Nostoc ellipsosporum. The protein binds with high affinity to the viral envelope glycoprotein gp120 and irreversibly inactivates diverse HIV strains. A fusion gene consisting of cvn, sumo and 6xHis tag was synthesized by PCR according to the codon bias of Escherichia coli. The fusion protein is expressed in the cytoplasm of E. coli in a soluble form and up to 28% of the total protein. The recombinant CVN was purified to homogeneity by 2 rounds of Ni-NTA affinity chromatography and one round of SUMO protease cleavage. Bioactivity assay demonstrated that SUMO-CVN and CVN bound to gp120 with nanomolar concentration. In addition, CVN showed potent anti-HSV-1 and anti-HIV-1 activities in in vitro cellular assays. Therefore, the 6xHis SUMO fusion expression and purification system provides a better approach for large scale production of CVN for further microbicide development.

Abstract:In order to optimize the fabrication of SiO2 tubes immobilized with antibody for hepatitis C virus antigen (HCAg) detection, we formed the activated amino on the surface of SiO2 tubes by using the activation of aminosilane. Then we immobilized the hepatitis C virus (HCV) monoclonal antibody on the surface of SiO2 tubes by using glutaraldehyde as a chemical cross-linker, followed by detecting HCAg. Sequence tests showed that when the SiO2 tubes were treated in 10% (V/V) aminosilane solution and 3% (V/V) glutaraldehyde solution for 3 hours and 2 hours, respectively, the HCV monoclonal antibody had high immobilization efficiency and low nonspecificity, and the HCAg was detected to 1 ng/mL. This experiment can provide principle and experimental data for establishment of HCAg magnetic immunoassay system.

Abstract:As a key role in mussel defense system, Mytilin is an important antibacterial peptide isolated from the mussel serum. The structural and functional researches on Mytilin showed that the fragment connecting two β-sheets in a stable β-hairpin structure was probably required for antimicrobial activity. To elucidate the structural features and the antimicrobial activity of this fragment, we re-designed and synthesized two peptides corresponding to the main mimic structures of Mytilin-1 from Mytilus coruscus, we named these two peptides Mytilin Derived Peptide-1 and Mytilin Derived Peptide-2, respectively. Using a liquid growth inhibition assay, we evaluated their activity towards Gram-positive, Gram-negative bacteria and fungus. The results showed that both peptides can inhibit the growth of Gram-positive, Gram-negative bacteria and fungus. Besides, these two peptides showed high stability in heat water and human serum. These works laid the foundation for further research on the molecular mechanism of Mytilin and for further exploitation of antibacterial peptides with lower molecular mass and more stable structure.