Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “vector engineering”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,279 records · Page 71Linked to original sources
PubMed2002

Enhanced phagemid particle gene transfer in camptothecin-treated carcinoma cells.

Engineered phage-based vectors are an attractive alternative strategy for gene delivery because they possess no natural mammalian cell tropism and can be genetically modified for specific applications. Genotoxic treatments that increase the transduction efficiency of single-stranded adeno-associated virus were tested on cells transfected by single-stranded phage. Indeed, green fluorescent protein transgene expression by epidermal growth factor-targeted phagemid particles increased with heat shock, UV irradiation, and camptothecin (CPT) treatment. CPT resulted in transduction efficiencies of 30-45% in certain human carcinoma cell lines and reduced the minimal dose needed to detect green fluorescent protein-expressing cells to as low as 1-10 particles/cell. Targeted phage transduction was effective in many tumor cell lines and in prostate tumor xenografts with CPT treatment. Taken together, these data suggest the feasibility of using phage-based vectors for therapeutic gene delivery to cancer cells.

Animals↗
PubMed2001

[The application of genetic engineering to the petroleum biodesulfurization].

The developed course and reaction mechanisms of petroleum biodesulfurization were introduced. The recent development of genetic engineering technology, which used in desulfuration strain's construction, reconstruction and other fields, was summarized emphatically. Its current research situation internal and overseas and the developing prospect were simply analyzed, and our research designs were submitted.

Biodegradation, Environmental↗
PubMed2002

[Expression of adenovirus-mediated pGH cDNA with first intron in CHO cells].

The recombinant adenoviruses containing pGH cDNA and pGH cDNA with the first intron under the control of CMV promoter were constructed respectively by homogenous recombination method. The results showed that the recombinant adenoviruses could mediate pGH cDNA expression in CHO cells infected with the recombinant adenoviruses. The expression level of pGH cDNA with the first intron increased by 117% compared with pGH cDNA without intron. This indicate that the first intron of pGH gene have the function of improving the expression of the pGH gene.

Adenoviridae↗
PubMed2002

In vitro organogenesis and genetic transformation in popular Cucumis sativus L. through Agrobacterium tumefaciens.

The effect of growth regulators and culture conditions on the morphogenetic response of cotyledonary leaf discs was studied in popular cucumber variety (Cucumis sativus cv. Sheetal). Organogenesis was induced directly without any intervening callus phase on Murashige and Skoog medium supplemented with different concentrations of benzyladenine and indole propionic acid. Best results (93%) were obtained in the presence of the 4 mg/L benzyladenine and 1 mg/L IPA. The elongated shoots were rooted in basal medium with 1 mg/L indole butyric acid, hardened and transferred to the field conditions. Genetic transformation system has been established for Cucumis sativus cv. Sheetal, plants by infecting cotyledonary explants with Agrobacterium tumefaciens strain LBA4404 carrying binary plasmid pBI121, which contains scorable marker, beta-glucuronidase and selectable marker nptII under the CaMV 35S promoter. Infection was most effective when explants were infected with Agrobacterium for 15 min and co-cultivated for 2 days in the co-cultivation medium. Shoots were regenerated directly from cotyledonary leaf explants in the presence of kanamycin (50 microg/ml) and analysed. Southern blot analysis confirmed that transformation had occurred. This method will allow genetic improvement of this crop by the introduction of agronomically important genes.

Agrobacterium tumefaciens↗
PubMedDate not supplied

Engineering crops, a deserving venture.

Plant transformation has had a deep impact on several aspects of basic and applied research. Genetic transformation has offered new opportunities compared to traditional breeding practises since it allows the integration into a host genome of specific sequences leading to a strong reduction of the casualness of gene transfer. One of the first target areas was plant protection against pests, pathogens and environmental stresses while the recent plant engineering programs are aimed at increasing food quality, in particular at increasing nutritional characteristics of food crops. Moreover, transgenic plants, tissue or cell cultures represent an attractive biological system for producing heterologous proteins since they offer economic and qualitative benefits. High yield production can be obtained and large-scale commercial production will take advantage of the existing infrastructure for crop cultivation, processing and storage. There are also qualitative benefits since protein synthesis secretion and post-translational modifications are similar in plants and animal cells. There are no human viral pathogens harboured by plants: thus, especially for pharmaceuticals, plants represent the safer production system. Plant transformation has become an essential instrument also for basic research, in particular for the functional characterisation of genes identified by sequencing of whole genomes. Large collections of insertion mutants have been obtained in the model plant Arabidopsis to provide a high level of genome saturation that means 95% chance of inactivating any gene at least once. To instil greater public confidence in modern plant biotechnology recent advances have already been made to overcome the potential risks for human health and environment.

Agriculture↗
PubMed2003

[Immuno-therapeutic study of anti-idiotype minibody (single chain Fv-CH3) on ovarian carcinoma bearing mice].

OBJECTIVE: An anti-idiotypic minibody with optimal antigenicity which mimicking ovarian cancer antigen was used for therapeutic research in mice model bearing ovarian cancer. METHODS: Using gene engineering technique, prokaryotic expression vector was constructed by genetic fusion of 6B11scFv to human IgG1 hinge and CH3 region. The fusion protein named minibody was induced with IPTG in E. coli and analyzed with Western blot and inhibition ELISA tests respectively. Twenty human-PBL-SCID mice bearing i.p. Skov3.ip1 cells were divided into two groups (10 per-group), 10 mice were immunized repeatedly by minibody every two weeks for three times. Indirect ELISA test was employed for analyzing the characterization of anti-anti-idiotypic scFv (Ab3). The latent period of ascites growth and the mean survival time were observed respectively. CD4+ and CD8+ T cells from the spleen of immunized mice were assayed by flow cytometry. RESULTS: SDS-PAGE gel electrophoresis showed that a protein band with molecular weight of 50,000 appeared as the expected size after transformation and induction the host bacteria BL21 (DE3). The expressed minibody could be reacted with COC166-9 (Ab1 of 6B11) and binding goat anti-human IgG1 antibody in Western blot. Inhibition ELISA showed minibody had the capacity of binding ovarian cancer monoclonal antibody COC166-9 instead of primal antigen. Ab3 could be detected in the sera of immunized mice with minibody by ELISA test. Ab3 reached the highest at the 14th day after last vaccination and lasted for 6 weeks. The ratio of CD4+/CD8+ was the highest at the 13th day after last vaccination. The latent period of ascites growth were (37.7 +/- 5.5) days and (48.6 +/- 14.3) days (P = 0.04) respectively; while the mean survival time were (42.5 +/- 1.8) days and (59.4 +/- 16.8) days (P = 0.011) in the control and minibody group respectively. CONCLUSIONS: These results demonstrate the successful construction and expression minibody with good immune activities of 6B11scFv and human IgG1 molecules function. Antigenicity is increased without adjuvants and partial humanization is realized. Minibody can induce humoral anti-idiotypic immunity responses against ovarian carcinoma in vivo. When ascites formation was delayed or prevented and the survival was prolonged in minibody group. We expect that minibody may be used as tumor vaccine to ovarian carcinoma in the future clinical trails.

Animals↗
PubMed1990

Use of recombinant DNA technology for engineering mammalian cells to produce proteins.

The recent advances in molecular biology have merged with somatic cell genetics and cell biology to allow mammalian cells to be extremely useful for the expression of foreign genes. This chapter has focused primarily on the approaches and potential limitations to high-level expression of proteins in mammalian cells. Future developments will involve the modification of mammalian cells in order to increase the efficiency of the various steps in protein processing and secretion. The ability to genetically engineer mammalian cells to produce high levels of desired proteins is presently complemented by advances in biochemical engineering which involve the ability to grow mammalian cells in very large volumes or at very high densities with reduced serum requirements. As a result, the cost for production of gram quantities of a protein from a mammalian host cell are approaching the cost of proteins from a mammalian host cell are approaching the cost of proteins similarly derived from microbial systems with all the advantages that mammalian systems afford.

Animals↗
PubMed1992

Antibody engineering by codon-based mutagenesis in a filamentous phage vector system.

A novel codon-based mutagenesis procedure is described that allows rapid and efficient modification of antibody amino acid sequences expressed as F(ab) fragments in M13. The procedure succeeded in generating a library of mutations in the complementarity-determining regions of chimeric L6, an antibody against a tumor-associated Ag. A set of anti-Id antibodies (anti-Id 1, 3, and 7) that bind near the L6 Ag-binding site served as model Ag. The goal was to select mutant antibody sequences that altered the L6 reactivity with the anti-Id in subtle ways, i.e., to eliminate the binding to one anti-Id while preserving other reactivities or to identify mutants with increased binding. A high frequency of variant M13 phage clones exhibiting altered specificity for the anti-Id were identified. Codon-based mutagenesis in conjunction with the M13 antibody expression and screening system should provide an efficient and general approach for redirecting the specificity and potentially improving the affinity of antibodies in vitro.

Amino Acid Sequence↗
PubMed1992

Genetically engineered antibodies: progress and prospects.

Techniques of genetic engineering and expression have been applied to the production of antibodies in a variety of expression systems. Novel antibodies have been produced with a variety of modifications: as chimeric antibodies, as "humanized" antibodies, with catalytic groups, as bifunctional or fusion proteins, and as functional fragments such as Fabs or Fvs. The domain structure of the antibody is favorable to such manipulation; the novel proteins often retain their antibody-derived activity and acquire new properties as well. Chimeric and complementarity-determining region (CDR)-grafted antibodies have been effective in immunotherapy, but problems of immunogenicity remain. Combinatorial libraries produced in bacteriophage may present an alternative to animal immunization as a source of antigen-binding specificities. Structural and mutational analysis of variable regions is providing useful information about the requirements of the variable region for antigen binding. Careful analysis and comparison of effector functions among immunoglobulin isotypes may be applied to the design of effective therapeutic antibodies.

Animals↗
PubMed2004

Growth factor treatment of neurodegenerative disorders: new developments pave the way for clinical success.

Neurotrophic factors have received significant attention in recent years for their potential use in the treatment of neurodegenerative and other nervous system disorders. However, the first attempts to apply factors such as nerve growth factor, glial-derived neurotrophic factor and ciliary neurotrophic factor failed to demonstrate any significant benefits in the clinic, despite a wealth of positive preclinical data. Recent advances in our understanding of the biology of neurotrophic factors in combination with the development of several new and improved delivery methods, for example, genetically engineered cells and viral vectors, have revitalized the interest in these potential nervous system protein therapeutics, and influenced the design of new clinical trials.

Animals↗
PubMed1992

Cell targeting by murine recombinant retroviruses.

Cell targeting by murine retroviruses carrying recombinant genes would have numerous applications such as immortalization of under-represented cell types from complex cellular mixtures, increasing therapeutical yields in the case of gene therapy and delivery of specific genes at any location and at any moment of the life-time of living animals. To this aim, we are currently developing techniques that allow binding of viral particles to specific cell membrane markers different from the natural receptors. We have shown that biochemical bi-specific molecular adaptors able to bind both viral particles and cell surface molecules may reveal appropriate for piloting viruses toward specific cell types. More recently, we have undertaken the genetic engineering of the retroviral envelope glycoprotein in order to modify its natural tropism. This approach is discussed below.

Defective Viruses↗
PubMed2005

[Osteogenesis of rabbit skin fibroblast transfected with core binding factor a1/osteoblast specific transplanting factor-2 gene].

OBJECTIVE: To study osteoblastic phenotype expression of New Zealand rabbit skin fibroblasts transfected with mouse core binding factor a1/osteoblast specific transplanting factor-2 gene (Cbfa1/Osf2). METHODS: Cbfa1/Osf2 gene, engineered into eukaryotic expression vector pSG5, was introduced into New Zealand rabbit skin fibroblasts with catholyte liposomes-Lipofectamine 2000. Meanwhile, those transfected pSG5 and un-transfected were set the control groups. The expression of Cbfa1 gene, osteocalcin (OCN) gene, alkaline phosphatase (ALP) gene and pre-peptide 2 alpha gene of collagen type I were detected by RT-PCR assay. Cbfa1 protein was detected by Western-Blot assay, in-cell ALP activity by p-nitrophenyl phosphate (PNPP) assay and OCN content in the supernatant by radio-immunity method. The ossification nodules was detected by Alizarin-Red staining and scanning electron microscope. RESULTS: Cbfa 1mRNA and Cbfa1 protein were expressed in New Zealand rabbit skin fibroblasts transfected with pSG5-Cbfa1/Osf2 from the first day to the fifth day, but they were not detected in the control groups. In the pSG5-Cbfa1/Osf2 transfected group, the expression of ALP gene and OCN gene were respectively induced from the third day and the forth day, pre-peptide 2 alpha gene of collagen type I was enhanced from the third day. From the sixth day, ALP activity greatly increased, OCN strongly secreted, and they were maintained at a high level for about 4 weeks, and the difference was significant compared with the control group (P < 0.05). On the forty-second day, ossification nodules were found on the surface of pSG5-Cbfa1/Osf2 gene transfected cells. CONCLUSIONS: New Zealand rabbit skin fibroblasts transfected with pSG5-Cbfa1/Osf2 can express osteogenesis-related genes and proteins, and form ossification nodules on their surface.

Alkaline Phosphatase↗
PubMed2003

[Genetically marking of natural biocontrol bacterium Bacillus subtilis strains with green fluorescent protein gene].

The full length sequence of the promoter and gfp gene were obtained respectively by PCR with two pairs unique primers PxyF/R and primers gfpF/R, which were designed according to the gfp gene and promoter sequence of xylase operon from Bacillus subtilis 168, and the DNA template plasmids pHT315-xyIR and pGFPuv. Furthermore, the fused translational expression cassette PxylR-gfp was constructed using overlapping PCR technique with the primers pair PxyF/gfpR and the mixture of above PCR production. After being digested by Kpn I and Sph I , PxylR-gfp expression cassette was inserted into E. coli-B. thuringiensis shuttle vecter pHT315 and E. coli-B. subtilis shuttle vecter pRP22, and the resulted recombinant plasmids were named as pGFP315 and pGFP22 respectively. Both recombinant plasmids were transferred into B. subtilis lab strain 168 and the resulted transformants are bright green performance under 365 nm UV light. However, only pGFP22 can be introduced into the natural strain B916. The transformants containing pGFP22 have bright green performance under 365 nm UV light and was named B916-gfp. Antifungal activities testing results proved that there is no obvious difference between B916 and the engineered strains B916-gfp. Research results also showed that the stability of B916-gfp was 94% after growth about 175 generations at 37 degrees C, and the losing rate of plasmid was less than 3.5 x 10(-4) per generation.

Bacillus subtilis↗