OBJECTIVETo achieve secretory and extracellular production of recombinant dengue virus serotypes I-IV envelope glycoprotein domain III (DENV-1-4 EDIII) in Pichia pastoris.

METHODSEDIII genes of DENVI-IV were amplified and cloned into vector pPIC9K, respectively. These recombinant plasmids were then linearized and transferred into Pichia pastoris strain GS115. Clones highly produced in 4.0 mg/ml G418 were amplified and induced by methanol to achieve the secreted recombinant proteins. Ni-NTA agarose beads were used for purification, while SDS-PAGE and Western blotting were used for identification.

RESULTSThe recombinant plasmids pPIC9K-DENV-1-4 EDIII were constructed and successfully transferred into Pichia pastoris strain GS115. The recombinant EDIII proteins were expressed in a secretory way with the molecular weight about 12 × 10(3) and specifically identified by anti-His monoclonal antibody and anti-DENVI-IV mice sera.

CONCLUSIONDENVI-IV EDIII proteins are successfully achieved from Pichia pastoris expression system and could be used for development of dengue vaccines, diagnostic reagents and study of biological function of the E protein.

Dengue Virus ; genetics ; Genetic Vectors ; Pichia ; metabolism ; Recombinant Proteins ; genetics ; Viral Envelope Proteins ; secretion

Constructing ethanologenic strains with cellulose activity is important to achieve consolidated bioprocessing of lignocellulose for ethanol production. In this study, we integrated the pyruvate decarboxylase gene pdc and alcohol dehydrogenase gene adhB from Zymomonas mobilis ZM4 into Escherichia coli JM109 by Red recombination method to generatea recombinant strain E. coli P81 that could produce ethanol from glucose. Abeta-glucosidase gene bglB from Bacillus polymyxa 1.794 was cloned into the recombinant E. coli P81 and beta-glucosidase was expressed to give a new recombinant strain E. coli P81 (pUC19-bglB) with dual functions of cellobiose degradation and ethanol production. The extracellular beta-glucosidaseactivity was 84.78 mU/mL broth and the extracellular cellobiase activity of E. coli P81 (pUC19-bglB) was 32.32 mU/mL broth. E. coli P81 (pUC19-bglB) fermented cellobiose to ethanol with a yield of 55.8% of the theoretical value, and when glucose and cellobiose were co-fermented, the ethanol yield reached 46.5% of thetheoretical value. The construction of consolidated bioprocessing strain opens the possibility to convert cellobiose to ethanol in a single bioprocess.
Bacterial Secretion Systems ; Cellulose ; metabolism ; Escherichia coli ; genetics ; metabolism ; Ethanol ; metabolism ; Fermentation ; Recombinant Proteins ; biosynthesis ; genetics ; beta-Glucosidase ; biosynthesis ; genetics

Aspergillus niger is an important industrial workhorse with extensive application in the sectors of industrial enzymes, heterogeneous proteins, organic acids and etc. The disclosure of its genomic sequence to the public brought the study of A. niger into the post-genomic era. Diverse omic data are being produced massively and rapidly, which largely upgrades our understanding to the hyperproduction mechanism of A. niger to a systems and molecular level. At meanwhile, its genetic operating system is becoming mature, which enables genome-scale genetic perturbation within A. niger. In conclusion, we are on the right way to redesign and engineer A. niger to an omnipotent cellular factory.
Aspergillus niger ; genetics ; metabolism ; Biotechnology ; methods ; Enzymes ; genetics ; secretion ; Gene Expression Regulation, Fungal ; Genes, Fungal ; Genome, Fungal ; Protein Biosynthesis ; genetics ; Recombinant Proteins ; secretion ; Transcription, Genetic

Selection of suitable signal peptides is an important factor for efficient secretion of heterologous proteins. We defined structural fusion degree (SFD) as the compatibility degree of target proteins and signal peptides by a bioinformatics approach. We mathematically analyzed the interaction of fused signal peptides and adjacent residues of proteins, and proposed a mathematical model of extended signal region and the protein. SFD Features was extracted from this model to characterize the secretability of heterologous proteins. Simulation tests showed that SFD features can effectively discriminate high secretory proteins from poor ones in the host Bacillus subtilis. Results from this research will be useful in signal peptide selection and have a better guiding significance for the optimization of heterologous protein secretion.
Amino Acid Sequence ; Bacillus subtilis ; genetics ; metabolism ; Bacterial Proteins ; genetics ; metabolism ; Biotechnology ; methods ; Membrane Transport Proteins ; genetics ; metabolism ; Metalloendopeptidases ; genetics ; metabolism ; Molecular Sequence Data ; Protein Sorting Signals ; genetics ; Proteins ; secretion ; Recombinant Fusion Proteins ; genetics ; metabolism

In order to obtain a high activity antibacterial peptide, An expression vector pPICZalphaA-pl is constructed with a tandem of four antimicrobial peptides in the same direction,which includes Protegrin-1 (PG-1), Scorpion Defensin (SD), Metalnikowin-2A and Sheep Myeloid Antibacterial Peptide (SMAP-29) (serial number in GenBank are AAB27599, AAAB27538, P80409 and P49928 respectively). At the same time the expression vector pPICZalphaA-sd which express Scorpion Defensin was contructed. The expression vectors of pPICZalphaA-pl and pPICZalphaA-sd were linearized and transformed into the yeast host strain X-33 respectively. Under the control of the promoter AOX1 (alcohol oxidase1), the peptides PL and SD were secreted expressed. Their heat-stable property, acid-stable property and MIC were detected in vitro. The results suggest the peptides PL and SD have good heat-stable and acid-stable properties, and the combinant PL peptide showes higher antibacterial activity against several Gram-positive bacteria (G+) and Gram-negative bacteria (G-) than the peptide SD, especially against Escherichia coli. The antibacterial activity of combinant antimicrobial peptide PL shows its far exploiting perspective.
Animals ; Anti-Infective Agents ; metabolism ; pharmacology ; Antimicrobial Cationic Peptides ; genetics ; pharmacology ; secretion ; Bacillus subtilis ; drug effects ; growth & development ; Blood Proteins ; genetics ; pharmacology ; secretion ; Cathelicidins ; Defensins ; genetics ; pharmacology ; secretion ; Electrophoresis, Polyacrylamide Gel ; Escherichia ; drug effects ; growth & development ; Hydrogen-Ion Concentration ; Pichia ; genetics ; Recombinant Fusion Proteins ; genetics ; pharmacology ; secretion ; Salmonella ; drug effects ; growth & development ; Scorpions ; metabolism ; Sheep ; metabolism ; Staphylococcus aureus ; drug effects ; growth & development ; Time Factors

To obtain the recombinant pZP3alpha protein for the study of the contraceptive vaccines, the DNA sequence (446-1423) encoding purified pZP3alpha was inserted into a vector--pPICZalphaA. The recombinant plasmid pPICZalphaA-pZP3alpha was linearized and then transformed into Pichia pastoris GS115 by electroporation. Engineering strains were attained by screening with zeocin and induced to produce rpZP3alpha in high-density fermentation. Then rpZP3alpha was purified by Cu2+ metal affinity column chromatography from the separated and concentrated fermentative supernatants. The purified rpZP3alpha was identified by SDS-PAGE and Western blot, and the quantity, purity and rate of recovery of the rpZP3alpha were analyzed by Quantity One software. One male rabbit was immunized with the Cu-NTA-purified rpZP3alpha. The antibody responses against rpZP3alpha and porcine ZP were detected by ELISA and the indirect immunofluorescence. Engineering strains expressing rpZP3alpha in secretion were constructed. A 46kD component named rpZP3alpha which can react with anti-pZP3 antibody was purified from fermentative supernatants of engineering strains and the average yield of purified rpZP3alpha obtained from fermentative supernatants was 8mg/L. The purity and the rate of recovery were up to 92% and 63% respectively. The anti-rpZP3alpha antiserum was prepared by immunization of a male rabbit with purified rpZP3alpha. This anti-rpZP3alpha antiserum could react with rpZP3alpha and purified pZP3 in ELISA and bind to porcine zona pellucida which produced bright green fluorescence in the indirect immunofluorescence. The rpZP3alpha (46kD) protein could be successfully expressed in the Pichia pastoris expression system. And this protein retained the immunogenic activity of natural pZP3.
Animals ; Egg Proteins ; genetics ; metabolism ; Electroporation ; Fermentation ; Immunization ; Male ; Membrane Glycoproteins ; genetics ; metabolism ; Pichia ; genetics ; metabolism ; Rabbits ; Receptors, Cell Surface ; genetics ; metabolism ; Recombinant Proteins ; genetics ; immunology ; secretion ; Swine ; Zona Pellucida Glycoproteins

OBJECTIVETo investigate the transduction efficiency of serotype 1, 2, 5, 6, 7, 8, 9, 10 recombinant adeno-associated viruses (rAAV) in human lung cancer cell line A549 cells and compare the transduction efficiency of conventional AAV vectors with that of self-complementary AAV (scAAV) vectors. Furthermore, the capacity of A549 cells expressing transgenic CD40L to stimulate dendritic cells (DCs) was evaluated.

METHODSLung cancer A549 cells were infected with 1 x 10(4) particules per cell of AAV encoding the green fluorescent protein (GFP) or human CD40L driven by CMV promotor, and transgene expression was analyzed by flow cytometry and fluorescence microscopy. Stimulation of isolated human dendritic cells by CD40L-expressing tumor cells was quantified by measuring secreted interleukin-12 with immunoassay.

RESULTSSerotype AAV2/5 transduced A549 cells much more efficiently than serotypes AAV2/1, AAV2/2, AAV2/6, AAV2/7, AAV2/8, AAV2/9 and AAV2/10. The transduction efficiency of scAAV2/5 was significantly higher than that of conventional AAV2/5. Furthermore, pre-treatment with carboplatin substantially increased AAV-mediated transgene expression. The scAAV2/5 vectors encoding human CD40L was used to generate CD40L. A549 cells transduce by these vectors were co-cultured with immature human DCs. As a consequence, interleukin-12 was released and measured in the culture supernatant. Specificity of immunostimulatory effect of CD40L was confirmed by blocking with a monoclonal antibody binding to human CD40L.

CONCLUSIONscAAV2/5 transduce lung adenocarcinoma A549 cell efficiently, and co-administration of chemotherapeutic agent carboplatin further enhances its transduction efficiency. It is confirmed that lung cancer cells infected with a CD40L-encoding scAAV2/5 construct can activate human DCs to secrete interleukin-12. Our findings provided a basis for future immunotherapeutic approaches including intratumoral transfer of stimulating factors.

Antineoplastic Agents ; pharmacology ; Blotting, Western ; CD40 Ligand ; genetics ; metabolism ; physiology ; Carboplatin ; pharmacology ; Cell Line ; Cell Line, Tumor ; Coculture Techniques ; Dendritic Cells ; cytology ; secretion ; Dependovirus ; classification ; genetics ; Flow Cytometry ; Gene Expression ; drug effects ; Genetic Vectors ; Green Fluorescent Proteins ; genetics ; metabolism ; Humans ; Immunoassay ; methods ; Interleukin-12 ; secretion ; Lung Neoplasms ; genetics ; metabolism ; pathology ; Microscopy, Fluorescence ; Recombinant Fusion Proteins ; genetics ; metabolism ; Serotyping ; Transfection

PURPOSE: Gastric cancer has the highest incidence rate among cancers in Asia. The advanced type of signet ring cell carcinoma has poor prognosis compared to other types of gastric cancer. The immuno-gene therapy with cytokine-based tumor vaccines has not yet been investigated for gastric cancer. The granulocyte macrophage colony-stimulating factor (GM-CSF)-based tumor vaccine has been demonstrated as the most potent stimulator for specific and long-lasting systemic tumor immunity. MATERIALS AND METHODS: In the present study, KATO III cells, the human signet ring cell gastric carcinoma cell line, were genetically modified by the transduction with the human GM-CSF cDNA or the modified hGM-CSF in replication-deficient retroviruses. The genomic integrations and mRNA expressions of the transgenes were determined by Southern and Northern blot analyses. RESULTS: Wild type (wt) or modified hGM-CSF was integrated into the genome of KATO III cells. The modified hGM-CSF mRNA was more stable than that of wt. The KATO III cells with the modified hGM-CSF produced higher level of hGM-CSF (12.4-19 ng/10(6)cells/48hrs) than that with wt hGM-CSF, when determined by enzyme-linked immunosorbent assay (ELISA). The secreted recombinant hGM-CSF could support the proliferation of the GM-CSF-dependent cell line, indicating that the hGM-CSF secreted by the transduced KATO III cells has biological activities. Irradiated, transduced KATO III cells continued to secret hGM-CSF without proliferation. CONCLUSION: Our results suggest that GM-CSF secreting KATO III cells could be tested for the treatment of gastric cancer as an allogeneic tumor vaccine as a part of immunotherapeutic treatment.
Base Sequence ; Blotting, Northern ; Blotting, Southern ; Cell Line, Tumor ; Enzyme-Linked Immunosorbent Assay ; Granulocyte Macrophage Colony-Stimulating Factors, ; Humans ; Mutagenesis ; RNA, Messenger/genetics/metabolism ; Recombinant Proteins/metabolism/*secretion ; Stomach Neoplasms/genetics/metabolism/pathology ; Transduction, Genetic

Animals ; Exocytosis ; drug effects ; physiology ; Glucose ; pharmacology ; Insulin ; secretion ; Insulin-Secreting Cells ; cytology ; drug effects ; metabolism ; Mice ; Microscopy, Fluorescence ; methods ; Potassium ; pharmacology ; Recombinant Fusion Proteins ; genetics ; metabolism ; Vesicle-Associated Membrane Protein 2 ; genetics ; metabolism

Entire 3ABC sequence of FMDV containing a 6 x his tag coding sequence at the N-terminal was obtained through PCR amplification using a pair of specific primers, subcloned into shuttle plasmid of pMelBac-B with a melittin secretion signal sequence and finally constructed recombinant plasmid of pMel-3ABC. After co-transfected the recombinant plasmid and linearized Bac-N-Blue DNA into Sf9 insect cell under intermediary agent of the Cellfectin, the result showed that we have already acquired recombinant baculovirus by screen of plaque assay and identification of PCR. Though the recombinant baculovirus infecting the Sf9 cells again, experiments indicated that 3ABC gene could express in insect cells and the expressed protein was secreted in the supernatant of Sf9 cell culture possessing favourable biological activities detected by adopting two methods of SDS-PAGE and Western blot. The result verified that the protein could respond with sera derived from FMDV infected animals, but have no responsibility with sera derived from health animals and vaccinated animals detected by indirect ELISA using antigen of expressed protein after purification with Ni-NTA his bind resin. Therefore, this study has established a solid foundation for establishing an effective diagnosis method to discriminating the FMDV infected animals from vaccinated animals.
Animals ; Antigens, Viral ; genetics ; immunology ; metabolism ; Blotting, Western ; Cattle ; Cell Line ; Cloning, Molecular ; Culture Media, Conditioned ; metabolism ; Electrophoresis, Polyacrylamide Gel ; Enzyme-Linked Immunosorbent Assay ; Foot-and-Mouth Disease ; immunology ; virology ; Foot-and-Mouth Disease Virus ; genetics ; immunology ; metabolism ; Gene Expression Regulation, Viral ; Immune Sera ; immunology ; Plasmids ; genetics ; Recombinant Proteins ; immunology ; secretion ; Sheep ; Spodoptera ; Swine ; Transfection ; methods ; Viral Nonstructural Proteins ; genetics ; immunology ; secretion