Abstract:In 1990, it was reported that the naked DNA encoding an antigen (so-called DNA vaccine) transduced directly into the muscle is able to induce immune responses just like antigen inoculation. Since then, a number of DNA vaccines against different diseases have been developed and shown to induce different levels of specific humoral and/or cell-mediated immunity. Efforts have been made to develop effective DNA vaccines against classical swine fever (CSF). This review covered the following aspects in the development and application of CSF DNA vaccines: construction and evaluation, application of adjuvants, combination with other vaccines and the existing problems and solutions.

Abstract:Besides the catalytic domain, some xylanases contained a non-catalytic domain which is named as carbohydrate binding module (CBM). CBM can be used to improve their binding-ability to insoluble substrates. We illustrated the importance of CBM by reviewing the source of CBMs, type of families, features of binding to insoluble substrates, specific amino acids involved in substrate-binding, linker peptides connecting the catalytic domain, and the effect of CBMs on xylanase thermostability. CBM is important for xylanase to break down complicate carbohydrates. Perspectives on engineering xylanase activity according to the characteristics of CBMs were given.

Abstract:It is one of the frequently utilized strategies for positive-negative selection to elevate the gene targeting efficiency in somatic cells by enriching targeted colonies. Knocking out prnp in animals by gene targeting can prevent it from expressing Prion protein (Pathogenic protein of transmissible spongiform encephalopathy), which enables it to resist infection of Prion. We constructed a bovine prnp biallelic targeting vector via the positive-negative selection strategy, and transfected the linearized vector into the bovine fetal fibroblasts through electroporation. Then, we selected cells in cell culture medium with G418 under a concentration of 600 μg/mL followed by Ganciclovir (GCV) under a concentration of 200 nmol/mL. In the end, we successfully obtained 176 cell clones. All these clones were identified by means of sequencing, immunofluorescence and western blotting, respectively, confirming that there existed 9 positive cell clones. The results showed that the bovine prnp gene was successfully knocked out. Conclusively, we provide an effective way to knockout bovine prnp gene, which could serve as the basis for producing prion protein gene knockout transgenic cloned cattle.

Abstract:Actinobacillus pleuropneumoniae (A. pleuropneumoniae), the causative agent of porcine contagious pleuropneumonia (PCP), is a significant pathogen of the world pig industry, vaccination is potentially an effective tool for the prevention of PCP. The purpose of present study was to enhance the immunogenicity of A. pleuropneumoniae live vaccine strain HB04C- (serovar 7), which was unable to express ApxIA, and to develop effective multivalent vaccines for the respiratory pathogens based on the attenuated A. pleuropneumoniae. We introduced a shuttle vector containing intact apxIA gene into HB04C-, generating HB04C2, an A. pleuropneumoniae serovar 7 live attenuated vaccine strain co-expressing ApxIA. Then we investigated the biological characteristics of HB04C2. We found that the shuttle vector expressing ApxIA was stable in HB04C2, and the growth ability of HB04C2 was not affected by the shuttle vector. We observed that HB04C2 elicited detectable antibodies against ApxIA and ApxIIA when it was administrated intratracheally as a live vaccine in pigs, and all immunized pigs were protected from heterologous virulent A. pleuropneumoniae (serovar 1) challenge. In conclusion, we demonstrated that A. pleuropneumoniae live vaccine could be used as a vector for expression of heterologous antigens.

Abstract:In this study, we cloned the NS3 gene from bovine viral diarrhea virus (BVDV) VEDEVAC strain. The result showed that the average P-distance of Pestivirus NS3 amino acid sequence was 0.07 and the VEDEVAC strain was classified to BVDV type 1. Using pET-30a(+) as vector and Escherichia coli Rosetta (DE3) as host, we obtained purified recombinant NS3 protein by Ni-NTA affinity chromatography. Western blotting analysis demonstrated that both BVDV positive serum and classical swine fever virus (CSFV) positive serum were able to recognize the recombinant NS3 protein. Indirect-ELISA assay indicated that the protein could be used as detection antigen.

Abstract:The present study was intend to clone and express the cDNA encoding Cyclophilin B(CyPB) of Schistosoma japonicum, its preliminary biological function and further immunoprotective effect against schistosome infection in mice. RT-PCR technique was applied to amplify a full-length cDNA encoding protein Cyclophilin B (Sj CyPB) from schistosomula cDNA. The expression profiles of Sj CyPB were determined by Real-time PCR using the template cDNAs isolated from 7, 13, 18, 23, 32 and 42 days parasites. The cDNA containing the Open Reading Frame of CyPB was then subcloned into a pGEX-6P-1 vector and transformed into competent Escherichia coli BL21 for expressing. The recombinant protein was renaturated, purified and its antigenicity were detected by Western blotting, and the immunoprotective effect induced by recombinant Sj CyPB was evaluated in Balb/C mice. The cDNA containing the ORF of Sj CyPB was cloned with the length of 672 base pairs, encoding 223 amino acids. Real-time PCR analysis revealed that the gene had the highest expression in 18-day schistosomula, suggesting that Sj CyPB was schistosomula differentially expressed gene. The recombinant protein showed a good antigenicity detected by Western blotting. Animal experiment indicated that the vaccination of recombinant CyPB protein in mice led to 31.5% worm and 41.01% liver egg burden reduction, respectively, compared with those of the control. A full-length cDNA differentially expressed in schistosomula was obtained. The recombinant Sj CyPB protein could induce partial protection against schistosome infection.

Abstract:Cytoplasmic transduction peptide (CTP) is a newly designed transduction peptide, by which special molecules can be carried out and localized into cytoplasmic compartment. Superoxide dismutase (SOD) is a protein that is difficult to go into cytoplasm. In this study, CTP-SOD fusion gene was amplified from human cDNA by PCR, and the active recombinant protein was successfully expressed in Pichia pastoris. HeLa cells pretreated with CTP-SOD showed a significantly improved survival against the pyrogallol-induced oxidative stress, suggesting CTP-SOD could cross the cell membrane more efficiently and protect cells from oxidative stress.

Abstract:The effect of temperature on a very high gravity ethanol fermentation using no cook process was investigated. We found that a gradient temperature control strategy could improve the fermentation efficiency significantly. With the assistance of a new raw starch hydrolyzing enzyme and a gradient temperature control strategy, the ethanol concentration could reach up to 20% (V/V) within 90 h using commercially available dry yeast, when sorghum was used as the raw material and the dry substrate concentration was controlled at 35%.

Abstract:We purified a sarcosine oxidase from Bacillus sp. strain BSD-8 isolated from soil. We purified the enzyme by ammonium sulfate precipitation, DEAE-cellulose, Toyopearl hydrophobic and Sephadex G-75 molecular sieve chromatography and characterized the purified sarcosine oxidase. This sarcosine oxidase was a flavin enzyme containing a noncovalently bound flavin with the subunit molecular mass of 51 kDa. The optimal temperature for this enzyme was 60?C and it showed its highest activity at pH 8.5. It was stable in the pH range of 8.0–10.0 and at the temperature of 60?C. Estimated by Lineveaver-Burk plots, the Km of the enzyme was 3.1 mmol/L. Ag+, Hg2+, SDS and Tween 80 dramatically inhibted the enzyme activity, whereas Tween 20 and Triton X-100 had no effect on enzyme activity. The thermostability of this enzyme was better than reported sarcosine oxidases, and it could be applied in enzymatic measuring of creatinine.

Abstract:White-rot fungus manganese peroxidase (MnP) that has great potential in degrading azo dyes is one of the extracellular glycolsylated heme proteins. MnP from Schizophyllum sp. F17 was isolated and purified by Sephadex G-75 gel filtration chromatography followed by DEAE-cellulose anion exchange chromatography. The molecular weight of the puried enzyme was 49.2 kDa, while the half-life of the MnP in the presence of 0.1 mmol/L H2O2 was 5?6 min. The efficiency of MnP-catalyzed reactions were determined by three key factors: the concentrations of Mn2+, H2O2, and the amount of MnP. Using single factor analysis, an optimized concentration of Mn2+, H2O2 and enzyme were optimized to be 1.2 mmol/L, 0.1 mmol/L, and 0.4 mL, respectively. A response surface methodology (RSM) employing two-level-three-factor full factorial central composite design was used to optimize the catalytic conditions. The result showed that the concentration of H2O2 and the interaction between H2O2 and MnP mostly affect the MnP catalytic efficiency. Finally, we show that the azo dyes could be efficiently decolorized by the purified MnP under optimized conditions.

Abstract:Streptomyces S24 has broad spectrum resistance to the Aspergillus in food and feed, such as Aspergillus flavus, Aspergillus niger, Asperegillus alutacells and so on. We studied the adsorption and desorption properties of antifungal substance from Streptomyces S24 on macroporous resins, screened the best elution solution and also investigated some physical and chemical characters of antifungal substance by determining the antifugal activity using oxford plate assay system. According to the analysis results, AB-8 resin offered the best adsorption and desorption capacity for antifungal substance and its saturated absorption capacity was 7.0822×104 μg/g, the optimal elution solution was 85% acetone and the dynamic desorption rate could reach 93. 82%. The antifungal substance was stable to heat and alkali, not sensitive to organic solvents, and sensitive to ultraviolet rays and acid. Based on its ultraviolet spectrometry, the antifungal substance was identified as heptaene macrolide antibiotic.

Abstract:Epidermal growth factor receptor (EGFR) and its ligands (EGF and TGFα) are over-expressed in a variety of tumors. Immunization EGF-carrier protein inhibits tumor growth through abrogating binding of EGF to EGFR. Here, a chimeric protein of EGF and TGFα (E5T) was genetically fused to Staphylococcal enterotoxin A (SEA), a bacterial superantigenic protein which promotes humoral B cell response through enhancement of Ag-specific CD4 T cells activity. The resulted fusion proteins were expressed in Escherichia coli and purified though metal chelating affinity chromatography. Immunization of E5T-mSEA fusion protein in mice induced production of high titers antibodies, which recognize both EGF and TGFα. Anti- E5T-mSEA serum at dilution of 1:10 significantly inhibited growth of A431 cell lines but had little effect on 293T cell lines.

Abstract:To study the functions of human Fibroblast growth factor receptor 2IIIc(FGFR2IIIc) gene in cancer cells, breast cancer cells MDA-MB-231 were infected by recombinant adenoviruses containing FGFR2IIIc and its S252W mutant, respectively. FGFR2IIIc gene was amplified from an existing plasmid and its S252W mutant was obtained by overlapping extension PCR. These two genes were separately cloned into the adenoviral shuttle plasmid pAdTrack-CMV, confivmed by DNA sequencing linearized, and co-transformed into Escherichia coli BJ-5183 with the adenoviral vector pAdEasy-1. The resulting recombinant expression vectors Ad-FGFR2IIIc and Ad-FGFR2IIIcS252W were linearized and transfected into HEK293A cells to get adenoviral particles. GFP was used to verify the gene expression. The recombinant adenoviral particles were harvested, titrated, and then infected MDA-MB-231 cells. The expression of FGFR2IIIc and its S252W mutant were examined by RT-PCR and Western blotting, and the effect of these recombinant adenoviruses on MDA-MB-231 cell proliferation was analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry. The results showed the recombinant adenoviral particles could infect MDA-MB-231 cells and express the target proteins. MTT showed that both FGFR2IIIc and its S252W mutant inhibited MDA-MB-231 cell proliferation, but the mutant was more effective. Flow cytometry showed that both FGFR2IIIc and its S252W mutant arrested MDA-MB-231 cell cycle at G0 /G1 phase, resulting in low cell proliferation.

Abstract:To solve the problem of low growth rate and metabolism level in suspension cultures of protocorm-like bodies (PLBs) of Dendrobium huoshanense. The effects of germanium on PLB proliferation and accumulation of polysaccharides together with nutrient utilization were investigated and the contents of reducing sugars, soluble proteins, the activities of antioxidant enzymes and redox status of the cells of PLB were analyzed. The results indicated that the optimum concentration of germanium dioxide (4.0 mg/L) significantly enhanced the cell growth and accumulation of polysaccharides, greatly improved contents of reducing sugars and soluble proteins, increased the activities of superoxide dismutase (SOD) and catalase (CAT) but decreased the activity of peroxidase(POD). The cell dry weight and production of polysaccharides were 32.6 g/L and 3.78 g/L, respectively. The analysis of cellular redox status showed that the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG) in cells and the activity of glutathione reductase were significantly increased by the addition of germanium dioxide. The suitable concentration of germanium dioxide was beneficial to the cell growth and the accumulation of polysaccharides.

Abstract:To study the possibilities for improvement of the ornamental character and production of secondary metabolites by using Wedelia trilobata hairy roots, we investigated the induction of W. trilobata L. hairy roots and its consumption changes of carbon resource, nitrogen resource, phosphate and calcium in the medium during liquid culture. The results showed that hairy roots could be incited from the cut edges of leaf explants 7 days after inoculation with Agrobacterium rhizogenes ATCC15834 and could have an autonomous growth on the medium without phytohormones. The PCR amplification showed that rol genes of Ri plasmid of A. rhizogenes was integrated and expressed into the genome of transformed hairy roots. The hairy root line grew very slowly in 0–7 days, very fast from 7 to 21 days. During the liquid culture of hairy roots, sucrose, NO3?-N, PO43?and Ca2+ in the medium could be gradually absorbed and utilized with time. The content of NO3?-N in the medium was 5.8% of the initial amount at day 7, while sucrose content was about 50% of the initial amount. At day 35, the NO3?-N and sucrose content in the medium was 1.82% and 3.39% of the initial amount, respectively. In combination with Ca2+ consumption, PO43? of the medium was rapidly absorbed and utilized. At day 7, the content of PO43? in the spent medium was only 1.76% of the initial amount; but even at day 35, the content of Ca2+ in the spent medium was still 61.3% of the initial amount. The results presented here had provided the possibilities on improvement the ornamental character and how to prepare optimum medium for large scale cultivation and production of secondary metabolites from W. trilobata L. hairy roots.

Abstract:We constructed shRNA vectors with different stem length, and tested the silencing effectiveness in mouse cells and embryos. We designed interfering RNAs with stems of 21 bp, 27 bp, and 29 bp. The enhanced green fluorescent protein gene was used as target gene. The synthesized single strands were annealed and cloned into psiSTRIKE and the recombinant plasmids (EGFP-21 siRNA, EGFP-27 siRNA, and EGFP-29 siRNA) were transfected into the mouse embryonic fibroblast with lipofection. The mRNA expression level of the enhanced green fluorescent protein gene was checked by real-time quantitative PCR. The silencing effectiveness of the 29 bp shRNA vector was stronger than which of the 21 bp and 27 bp. The findings in this study are of interest for selecting the hairpins for mouse individuals.

Abstract:PHD finger protein 8 (PHF8) is a novel protein with PHD domain and Jmjc domain, which may play important role in regulating transcription and histone demethylation. It is necessary to generate the antibody against PHF8 in order to further study its biological function. First we constructed plasmid pET41b-PHF8 (aa886-936) and expressed the GST-PHF8 (aa886-936) fusion protein in Escherichia coli BL21. We then purified the fusion protein by Glutathione Sepharose 4B beads and subjected to immunize the rabbits for acquiring antiserum. We obtained PHF8 polyclonal antibody by affinity purifying the antiserum with CNBr-activated Sepharose 4B beads. The antibody was effective in Western blotting and immunofluorescence with high specificity. Immunofluorescence also showed that PHF8 protein was located in nucleus in HeLa cells.

Abstract:Vibrio cholerae is an important foodborne pathogen, mainly causes acute intestinal infectious disease. The development of rapid method for detecting Vibrio cholerae is critical for early diagnosis of its infection. In this study, two pairs of specific primers were designed according to housekeeping gene mdh of Vibrio cholerae. Following optimization of the reaction, DNA loop-mediated isothermal amplification (LAMP) for rapidly detecting Vibrio cholerae was successfully established. The optimal reaction for the LAMP assay is 65?C for 60 min, with detection limit for cultivated Vibrio cholerae of 25 CFU/mL and for its contaminated food of 32 CFU/g. The specificity of the assay was determined using thirty-three kinds of same species or closely related bacteria, only Vibrio cholerae strains were specifically amplified. In practice, 85 pieces of positive samples were detected from 1057 pieces of shrimps, crabs, oysters, meat and human diarrhea complex using the LAMP method, which accorded with the detection result by ISO TS 21872-1-2007. Thus, the LAMP assay established in this study is a sensitive, rapid and simple tool for detecting Vibrio cholerae and will facilitate the surveillance for its control.

Abstract:The importance of chitinases in the physiological and developmental processes of fungi and insects makes themselves and their inhibitors important targets for biological pesticides. A chitinase was isolated from Bombyx mori and purified to electrophoretic homogeneity by ammonium sulfate precipitation and Sephadex G-150 column chromatography. The molecular mass was estimated to be about 88 kDa by SDS-PAGE, while the Km was calculated to be 22.3 μmol/L. Moveover, the optimal reaction temperature was 45?C, and the optimum pH was 6.0. The effect of metal ions and organic reagents on chitinase activity was investigated. The activity was enhanced by high concentration of Mn2+, while was strongly inhibited by Cu2+ and SDS. These results provide a basis for screening the chitinase-based biological pesticide.

Abstract:Myostatin, a member of the transforming growth factor β (TGF-β) family, is a negative regulator for muscle growth. Loss of the function of this gene is associated with the phenotype described as “double muscling”, an extreme form of muscle development characterized by a large increase in muscle mass. Two replacement vectors, pA2T-Mstn4.0 and pA2T-Mstn3.2, were constructed, linearized, and transfected into the bovine fetal fibroblasts through electroporation. 170 drug-resistant cell colonies were obtained in cell culture medium containing 600 μg/mL G418 and 50 nmol/L GCV. Targeted homologous integration occurred in colony No. 58 as identified by PCR, and the targeted colony was further confirmed by sequencing and Southern blotting. This suggested that one allele of myostatin was successfully mutagenized in bovine fetal fibroblasts.