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At least 973 records · Page 54Linked to original sources
PubMed2004

The person, the soul, and genetic engineering.

Argument about the ethical possibility of the therapeutic use of embryonic stem cells depends critically on the evaluation of the moral status of the very early embryo. Some assert that at the blastocyst stage it is only potentially human, not yet possessing the full ethical status of personhood, while others assert that from its formation the embryo possesses all the moral rights of a human person. It is shown that a decision on this issue is closely related to how human nature is to be understood. The idea of a person as a dual combination of body and spirit correlates naturally with the assertion of absolute personhood from conception, while an idea of human psychosomatic unity encourages a development picture in which the embryo only grows gradually into personhood. The latter view is seen to be encouraged by new advances in science which emphasise the importance of the concept of information in the discussion of complex systems. Other ethical issues related to human genetics are also briefly reviewed.

Cloning, Organism↗
PubMed1998

Exemplifying guidelines for preparation of recombinant DNA products in phase I trials in cancer: preparation of a genetically engineered anti-CEA single chain Fv antibody.

Products of recombinant DNA technology have potential for the diagnosis or treatment of cancer. There is a need to investigate whether they function by the intended mechanism in small phase I clinical trials before their suitability for more extensive studies can be assessed. Quality and safety of these products should be assured prior to their use in humans in a way which is appropriate to the preliminary nature of the trials but not inhibitory to progress. The Cancer Research Campaign control recommendations for products derived from recombinant DNA technology (Begent RHJ and associates. Eur J Cancer 1993, 29A, 13, 1907-1910) provide guidelines for the production of new biotechnology products in academic research units within a relatively short time, while ensuring appropriate quality and safety. The practical application of the guidelines requires that solutions are found for the quality and safety issues during the production of recombinant products. We describe an approach to the relevant quality and safety issues during and after the production and purification of a genetically engineered anti-carcinoembryonic antigen (CEA) single chain Fv (scFv) antibody for a phase I trial of radioimmunoguided surgery with the intention of providing a model for other products.

Biotechnology↗
PubMed1996

[Development of genetically engineered chimeric and single chain antibodies against human brain glioma: a preliminary report].

In order to improve the clinical usefulness of mAb of mouse origin in targeting diagnosis and therapy for human brain glioma, it is necessary to humanize it and reduce its molecular size. By means of RT-PCR technique, a 348 bp heavy chain variable domain (VH), and a 318 bp light chain variable domains (VL) cDNA fragments were cloned from mouse hybridoma cell line SZ39 secreting mAb against human brain glioma. By recombinant DNA technique, the two cDNA fragments were linked to human IgG1 heavy chain CH1 and light chain kappa constant regions, respectively, to form a chimeric gene which was then inserted into an expression vector pHEN1-SZ39 Fab/Hu. In addition, the two cDNA fragments were connected directly with a universal linker and inserted to an expression vector pHEN1-SZ39 ScFv. The two expression vectors were separately introduced into E. coli HB2151 to secrete chimeric antibodies and single-clain antibodies, respectively. On ELISA and Western blot, the two genetically engineered antibodies bond to the same 180,000 cell surface membrane antigen on human brain glioma cell line SHG44 as did the parental mAb SZ39.

Amino Acid Sequence↗
PubMed2006

Milestones leading to the genetic engineering of baculoviruses as expression vector systems and viral pesticides.

The baculovirus expression vector system (BEVS) is widely established as a highly useful and effective eukaryotic expression system. Thousands of soluble and membrane proteins that, in general, are correctly folded, modified, sorted and assembled to produce highly authentic recombinant proteins have been cloned and expressed. This historical chronology and perspective will focus on the original, peer-reviewed discoveries that were pioneering and seminal to the development of the BEVS and that provided the basis for subsequent and more recent developments and applications.

Animals↗
PubMed1997

Human molecular genetics research at the International Centre for Genetic Engineering and Biotechnology.

The ICGEB started its activity in 1987 as a special project of UNIDO (United Nations Industrial Development Organization) and operates now as a fully autonomous International Organization, of which 40 countries are members at present. The mandate of ICGEB is to become a Centre of excellence for research and training in modern biology addressed to the needs of the developing world. The ICGEB consists of two main laboratories, one in Trieste (where the direction of the Centre is also located) and one in New Delhi, plus a network of 30 Affiliated Centres. The Centre operates through: 1) specific research programs of hish scientific content at the Trieste and New Delhi laboratories; 2) long term training through post-doctoral and pre-doctoral fellowships; 3) short term training; 4) collaborative research program, through which the Centre finances research projects of major impact to the need of the Member States; 5) scientific services, namely consultation for scientific programs, distribution of reagents and a bioinformatics network particularly geared to the human genome research. The research on human molecular genetics in particularly active in the Trieste Component and concerns the study at the molecular level of several genes important for human health: control of DNA replication, response to infectious diseases, cardiocirculatory diseases, cystic fibrosis and cancer. The methodologies for developing new diagnostic methods and for developing gene therapy protocols are actively pursued. Through these programs, the member countries have access to state-of-the-art technologies anf know-how essential for the development of the molecular approaches to medicine brought forward by the study of the human genome.

Biotechnology↗
PubMed2005

Genetically engineered, live, attenuated vaccines protect nonhuman primates against aerosol challenge with a virulent IE strain of Venezuelan equine encephalitis virus.

Two live, attenuated strains of Venezuelan equine encephalitis virus (VEE), IE1150K and V3526, were administered to macaques to determine if they could elicit protection against an aerosol challenge with virulent VEE virus of the IE variety (VEEV-IE). These viruses were rescued from full-length cDNA clones of 68U201 (VEEV-IE variety) and Trinidad donkey (VEEV-IA/B variety), respectively, and both have a furin cleavage site deletion mutation and a second-site resuscitating mutation. Both vaccines elicited neutralizing antibodies to viruses of the homologous variety but not to viruses of the heterologous variety. Eight weeks after vaccination, the macaques were challenged by aerosol exposure to virulent 68U201. Macaques vaccinated with V3526 were protected as well as macaques inoculated with IE1009, the wild-type infectious clone of 68U201. However, IE1150K failed to significantly protect macaques relative to controls. V3526 has now been shown to protect macaques against both IA/B [Pratt WD, Davis NL, Johnston RE, Smith JF. Genetically engineered, live attenuated vaccines for Venezuelan equine encephalitis: testing in animal models. Vaccine 2003;21(25-26):3854-62] and IE strains of VEE viruses.

Aerosols↗
PubMed2002

Genetically engineered active Qbeta replicase in rabbit reticulocyte cell-free system: a fusion protein of EF-Tu and EF-Ts is functional as the subunit of Qbeta replicase.

Qbeta replicase functioning in Escherichia coli is an RNA-dependent RNA polymerase composed of one phage-coded subunit and three host-coded proteins: ribosomal protein S1, and protein elongation factors EF-Tu and EF-Ts. Qbeta replicase lacking ribosomal protein S1 (alpha-less replicase) is capable of replicating some small RNAs. We attempted to create functional alpha-less replicase by co-expression of the mRNAs that code for the subunits of alpha-less replicase in a rabbit reticulocyte cell-free translation system. Replicase activity, however, could not be detected when both EF-Tu and EF-Ts were co-expressed with the phage-coded subunit. On the other hand, active alpha-less replicase was obtained when an EF-Ts-EF-Tu fusion protein was co-expressed with the phage-coded subunit. Consequently, we succeeded in generating genetically engineered active alpha-less Qbeta replicase which functions in a eukaryotic cell-free system.

Journal Article↗
PubMed1995

New mini-Tn5 derivatives for insertion mutagenesis and genetic engineering in gram-negative bacteria.

Five mini-Tn5 derivatives encoding resistance to Km, Cm, Gm, Tc, and Sm, coupled with the polylinker of the pBluescriptII plasmid, were constructed. These derivatives are carried by an ampicillin-resistant plasmid that has a conditional origin of replication from plasmid R6K and origin of conjugal transfer from the broad host range plasmid RP4. The new vectors are smaller than those previously described and possess numerous unique restriction sites inside the minitransposons for gene cloning in addition to SfiI and NotI sites found in their predecessors.

DNA Nucleotidyltransferases↗
PubMedDate not supplied

Genetically engineered and synthetic allergen derivatives: candidates for vaccination against type I allergy.

Type I allergy, a hypersensitivity disease affecting almost 20% of the population worldwide, is based on the IgE recognition of otherwise harmless antigens (i.e., allergens). Allergen-induced crosslink of effector cell-bound IgE antibodies leads to the release of biological mediators and thus to immediate disease symptoms (allergic rhinitis, conjunctivitis and asthma). Specific immunotherapy, the only causative treatment of Type I allergy, is based on the administration of increasing doses of allergens to allergic patients in order to yield allergen-specific non-responsiveness. Major disadvantages are 1. that current forms of allergen immunotherapy are performed with allergens difficult to standardize which cannot be matched to the patients reactivity profile and 2. that the administration of active allergen preparations can cause anaphylactic side effects. Through the application of molecular biological techniques many relevant environmental allergens have been produced as active recombinant proteins which allow component-resolved allergy diagnosis and thus represent the basis for patient-tailored forms of immunotherapy. Here we review molecular strategies which have been recently applied to generate genetically engineered and synthetic hypoallergenic allergen derivatives for patient-tailored and safe vaccination against Type I allergy.

Allergens↗
PubMed1994

Safety and immunogenicity of recombinants based on the genetically-engineered vaccinia strain, NYVAC.

NYVAC-based recombinants expressing pertinent immunogens from equine influenza virus (EIV), pseudorabies virus (PRV), Japanese encephalitis virus (JEV) and human immunodeficiency virus (HIV) were used to evaluate the safety and immunogenicity of this vector. Administration of either NYVAC recombinants or parenteral virus to mice, horses and swine was well tolerated with no notable local or systemic reactivities. Further, despite a highly attenuated phenotype, NYVAC was found to function effectively as an immunization vehicle capable of eliciting both humoral and cell-mediated immune responses.

AIDS Vaccines↗
PubMed2006

Transposon-free insertions for insect genetic engineering.

Methods involving the release of transgenic insects in the field hold great promise for controlling vector-borne diseases and agricultural pests. Insect transformation depends on nonautonomous transposable elements as gene vectors. The resulting insertions are stable in the absence of suitable transposase, however, such absence cannot always be guaranteed. We describe a method for post-integration elimination of all transposon sequences in the pest insect Medfly, Ceratitis capitata. The resulting insertions lack transposon sequences and are therefore impervious to transposase activity.

Animals↗
PubMed1991

Allele-specific activation of genetically engineered receptors.

The binding of agonists and antagonists to the beta-adrenergic receptor (beta AR) is postulated to involve an ionic interaction between the amine group of the ligand and the carboxylate side chain of Asp113 in the third hydrophobic domain of the receptor. To explore the importance of this interaction in the binding of ligands to the beta AR, a Ser residue was substituted for Asp113, and the ability of this mutant receptor to respond to compounds which could potentially interact with the hydroxyl side chain of the Ser residue was assessed. The mutant receptor was fully activated by catechol-containing esters and ketones, compounds which did not activate the wild-type beta AR. The demonstration that the molecular substitution of a single amino acid residue can alter the ligand binding specificity of the beta AR provides evidence that the chemical nature of this residue is a critical determinant in the recognition site of the receptor. Further, the ability to modify the specificity of a receptor by the replacement of amino acids at the binding site demonstrates the potential for the rational design of drugs which function specifically at genetically engineered receptors.

Adenylyl Cyclase Inhibitors↗
PubMed1999

Molecular dissection of mitogillin reveals that the fungal ribotoxins are a family of natural genetically engineered ribonucleases.

Mitogillin and the related fungal ribotoxins are highly specific ribonucleases which inactivate the ribosome enzymatically by cleaving the 23-28 S RNA of the large ribosomal subunit at a single phosphodiester bond. The site of cleavage occurs between G4325 and A4326 (rat ribosome numbering) which are present in one of the most conserved sequences (the alpha-sarcin loop) among the large subunit ribosomal RNAs of all living species. Amino acid sequence comparison of ribotoxins and guanyl/purine ribonucleases have identified domains or residues likely involved in ribonucleolytic activity or cleavage specificity. Fifteen deletion mutants (each 4 to 8 amino acid deletions) in motifs of mitogillin showing little amino acid sequence homology with guanyl/purine ribonucleases were constructed by site-directed mutagenesis. Analyses of the purified mutant proteins identified those regions in fungal ribotoxins contributing to ribosome targeting and modulating the catalytic activity of the toxin; some of the identified motifs are homologous to sequences in ribosomal proteins and elongation factors. This mutational study of mitogillin together with the recently published x-ray structure of restrictocin (a close relative of mitogillin) supports the hypothesis that the specific cleavage properties of ribotoxins are the result of natural genetic engineering in which the ribosomal targeting elements of ribosome-associated proteins were inserted into nonessential regions of T1-like ribonucleases.

Allergens↗
PubMed2004

Overexpression for commercial production of recombinant human insulin as A-chain and B-chain fusion protein in Escherichia coli through genetically engineered plasmids.

The construction of expression vectors encoding either the human insulin A- or B-chains fused to a synthetic peptide and the temperature-induced expression of the recombinant genes in Escherichia coli are reported. Using this two-chain approach we also describe the separate isolation of the insulin A- and B-chains from inclusion bodies and their subsequent assembly into native human insulin. The expression yields about 600 mg of the insulin B-chain per litre of culture. Under similar conditions the expression yield of the insulin A-chain corresponds to approximately 500 mg per litre of culture. This is the highest yield from shake flask experiments.

Escherichia coli↗
PubMed1998

Exploring development and disease through germ-line genetic engineering in the mouse.

New developments in mouse genetics have transformed the field of genetics from a reactive to a proactive science. Current technologies in transgenesis, chromosome engineering, and saturation mutagenesis are introduced. These approaches permit the creation of new mutations and consequent mutant phenotypes that facilitate both the understanding of functions of existing genes and the search for previously unidentified genes affecting important phenotypes in all mammals.

Animals↗
PubMed1999

Genetically engineered brain drug delivery vectors: cloning, expression and in vivo application of an anti-transferrin receptor single chain antibody-streptavidin fusion gene and protein.

A single chain Fv antibody-streptavidin fusion protein was expressed and purified from bacterial inclusion bodies following cloning of the genes encoding the variable region of the heavy chain and light chain of the murine OX26 monoclonal antibody to the rat transferrin receptor. The latter undergoes receptor mediated transcytosis through the brain capillary endothelial wall in vivo, which makes up the blood-brain barrier (BBB); therefore, the OX26 monoclonal antibody and its single chain Fv analog may act as brain drug delivery vectors in vivo. Attachment of biotinylated drugs to the antibody vector is facilitated by production of the streptavidin fusion protein. The bi-functionality of the OX26 single chain Fv antibody-streptavidin fusion protein was retained, as the product both bound biotin and the rat transferrin receptor in vitro and in vivo, based on pharmacokinetic and brain uptake analyses in anesthetized rats. The attachment of biotin-polyethyleneglycol-fluorescein to the OX26 single chain Fv antibody-streptavidin fusion protein resulted in illumination of isolated rat brain capillaries in confocal fluorescent microscopy. In conclusion, these studies demonstrate that genetically engineered single chain Fv antibody-streptavidin fusion proteins may be used for non-invasive neurotherapeutic delivery to the brain using endogenous BBB transport systems such as the transferrin receptor.

Animals↗