SEARCH · PubMed Health

Results for “Genetic Engineering”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 91 records · Page 5Linked to original sources

PubMed2006

Understanding the role of dietary components on atherosclerosis using genetic engineered mouse models.

The generation by genetic engineering of two murine models to investigate atherosclerosis, such as the apoE- and LDLr- deficient mice, is providing an extraordinaire knowledge of the effect of different nutrients on this complex disease. The present revision provides a comprehensive overview of the advances in this field that point to a remarkable complexity. While some controversies over puzzling results could be explained invoking potential nutrient interactions or different food sources of nutrients, it also appears that other factors such as sex, genetic background or immunological status are emerging as generators of differential responses to nutrients during the atherosclerotic process.

Alcohol Drinking↗

PubMed2005

[Chloroplast genetic engineering: a new approach in plant biotechnology].

Chloroplast genetic engineering, offers several advantages over nuclear transformation, including high level of gene expression, increased biosafety, remedying some limitations associated with nuclear genetic transformation, such as gene silencing and the stability of transformed genes. It is now regarded as an attractive new transgenic technique and further development of biotechnology in agriculture. In this article we reviewed the characteristics, applications of chloroplast genetic engineering and its promising prospects were discussed.

Biotechnology↗

PubMedDate not supplied

[Bioethics in genetic engineering].

The advances in the field of molecular biology and genetics have widened the possibilities for the diagnosis and treatment of hereditary diseases. At the same time research into this field has broken bounds of its legal and ethical regulation. The intention of this paper is not to analyze these advances from scientific and technical point of view which is the area of the specialist, but rather to review historical antecedents of genetic engineering; the legal and ethical repercussions of the human genome project (HGP); in vitro fertilization and embryo transfer (FIVET); the embryo research which is being caused out and which may be possible; other fields of genetics and cloning especially germinal cells and human beings; genetic diagnosis and its family, social and work repercussions; treatment through genetic engineering, research into cloning in order to obtain organs and tissues for transplants; and the use of genetic engineering in the biomedical industry. To avoid these advances working against humans, the organization and participation of multidisciplinary bodies are required to provide legal and ethical supervision.

Bioethical Issues↗

PubMed2006

Pathology of genetically engineered mouse models of pancreatic exocrine cancer: consensus report and recommendations.

Several diverse genetically engineered mouse models of pancreatic exocrine neoplasia have been developed. These mouse models have a spectrum of pathologic changes; however, until now, there has been no uniform nomenclature to characterize these changes. An international workshop, sponsored by The National Cancer Institute and the University of Pennsylvania, was held from December 1 to 3, 2004 with the goal of establishing an internationally accepted uniform nomenclature for the pathology of genetically engineered mouse models of pancreatic exocrine neoplasia. The pancreatic pathology in 12 existing mouse models of pancreatic neoplasia was reviewed at this workshop, and a standardized nomenclature with definitions and associated images was developed. It is our intention that this nomenclature will standardize the reporting of genetically engineered mouse models of pancreatic exocrine neoplasia, that it will facilitate comparisons between genetically engineered mouse models and human pancreatic disease, and that it will be broad enough to accommodate newly emerging mouse models of pancreatic neoplasia.

Animals↗

PubMed1990

Microcosm for assessing survival of genetically engineered microorganisms in aquatic environments.

Laboratory-contained microcosms are important for studying the fate and survival of genetically engineered microorganisms. In this study, we describe a simple aquatic microcosm that utilizes survival chambers in a flowthrough or static renewal system. The model was used to study the survival of genetically engineered and wild-type strains of Escherichia coli and Pseudomonas putida in the lake water environment. Temperature-dependent studies indicated that the genetically engineered microorganisms survived better or at least as well as their wild-type counterparts at 15, 25, and 30 degrees C. The genetic determinants of the genetically engineered microorganisms also remained fairly stable within the host cell under the tested conditions. In the presence of organisms indigenous to lake water, E. coli was eliminated after 20 days, whereas P. putida showed an initial decline but was able to stabilize its population after 5 days. A herbicide, Hydrothol-191, caused a significant decline in numbers of P. putida, but no significant difference was observed between the genetically engineered microorganisms and the wild-type strain. The microcosm described is simple, can be easily adapted to study a variety of environmental variables, and has the advantage that the organisms tested are constantly exposed to test waters that are continuously renewed.

Dicarboxylic Acids↗

PubMed2004

Genetically engineered polymers: status and prospects for controlled release.

Genetic engineering methodology has enabled the synthesis of protein-based polymers with precisely controlled structures. Protein-based polymers have well-defined molecular weights, monomer compositions, sequences and stereochemistries. The incorporation of tailor-made motifs at specified locations by recombinant techniques allows the formation of hydrogels, sensitivity to environmental stimuli, complexation with drugs and nucleic acids, biorecognition and biodegradation. Accordingly, a special interest has emerged for the use of protein-based polymers for controlled drug and gene delivery, tissue engineering and other biomedical applications. This article is a review of genetically engineered polymers, their physicochemical characteristics, synthetic strategies used to produce them and their biomedical applications with emphasis on controlled release.

Animals↗

PubMed1994

Problems in the introduction of genetically engineered microorganisms into the environment.

The use and release of genetically engineered microorganisms (GEMs) into the environment, usually the agricultural environment, is increasing exponentially. Potential applications of GEMs include crop production, pest management, degradation of environmental pollutants, mining and mineral recovery, and others. Several strategies of molecular and cellular biotechnology, such as recombinant DNA techniques, nuclear microinjection and cell fusion may be used to modify bacteria and fungi for useful purposes. The benefits expected from release of genetically engineered microorganisms, if safely applied, might be substantial in various fields. However, a safe introduction of GEMs into the environment requires full environmental and ecological risks assessment. Because of the wide scope of genetic engineering targets this review will focus on the application of GEMs potentially useful in agricultural practices (crop nutrition, pest and disease control) and ecological problems associated with the introduction of alien microorganisms into the environment.

Agriculture↗

PubMed2000

Hybrid anthracyclines from a genetically engineered Streptomyces galilaeus mutant.

The genetic engineering of antibiotic-producing Streptomyces strains is an approach that is emerging and ready to become established as a successful methodology in developing analogues of the original, pharmaceutically important, natural products obtained from the organisms. The current report highlights this succes by demonstrating the high-level production of novel anthracyclines. The biosynthetic pathways of the nogalamycin-producing Streptomyces nogalater and the aclacinomycin-producing S. galilaeus were combined by transferring the genes of S. nogalater polyketide synthetase into a nonproducing S. galilaeus mutant. The resulting anthracycline antibiotics that were produced possessed structural features characteristic of compounds from both of the undoctored Streptomycesstrains.

Antibiotics, Antineoplastic↗

PubMed1998

Strategies to improve plant resistance to bacterial diseases through genetic engineering.

Many different genetic strategies have been proposed to engineer plant resistance to bacterial diseases, including producing antibacterial proteins of non-plant origin, inhibiting bacterial pathogenicity or virulence factors, enhancing natural plant defenses and artificially inducing programmed cell death at the site of infection. These are based on our knowledge of the mechanisms of action of antibacterial compounds and of the successive steps in plant-bacterial interactions. This article presents the different approaches and demonstrates that, even though several of these ideas have already been applied, no commercial applications have yet been achieved.

Animals↗

PubMed2000

Characterization of genetically engineered mengoviruses in mice.

We have shown that genetically engineered mengoviruses containing artificially shortened 5' noncoding poly(C) tracts (e.g., C0 or C13UC10) are dramatically attenuated in adult Swiss/ICR mice when compared to wild-type virus or to a genetically engineered virus containing a wild-type length poly(C) tract (C44UC10). To explore further the relationship between poly(C) tracts and virulence, we have conducted more extensive characterizations of several engineered viruses in the murine model. Both short and long poly(C) tract viruses were highly virulent in newborn mice, underscoring the importance of age in poly(C)-mediated attenuation. Virus vMC24, with a tract sequence of C13UC10, was as attenuated in 4-week-old BALB/c, C.C3-H2k/LiMcdJ, and DBA/2 mice as in Swiss/ICR mice. But it was more pathogenic for C57BL/6 mice, and highly virulent for C3H/Hej and C3H/Hen mice, demonstrating the importance of murine genotype. As expected from its virulence in all mouse strains, vMwt, with a poly(C) of C44UC10, induced higher levels of viremia than vMC24. The vMwt also induced higher levels of circulating interferon and had reduced pathogenicity in chemically immunosuppressed Swiss/ICR mice. Similar immunosuppression did not increase the virulence of vMC24. Collectively, the data suggest that endogenous immune components and the immune competence of the host play significant roles in determining the susceptibility of mice to mengovirus infection.

Animals↗

PubMed1983

Prospects in plant genetic engineering.

The functional expression of a novel gene in a genetically engineered plant has not yet been reported. One major barrier in movement toward this goal is our limited understanding of the molecular bases of gene expression. Attempts to establish genetic engineering as a practical facet of plant breeding are also complicated by the fact that genes for most important plant characteristics have not yet been identified. However, the benefits to be gained from all aspects of plant improvement are stimulating research into both the development of plant transformation technology and the isolation and characterization of genes responsible for valuable traits. As scientists develop greater knowledge of plant molecular genetics, we can expect to see practical applications in such diverse areas as improvement of plant nutritional quality, decreases in fertilization requirements, and increases in resistance to environmental stresses and pathogens.

Agriculture↗

PubMed1992

Development of genetic engineering in Bacillus megaterium.

The opportunities for industrial genetic engineering in several species of Bacillus other than B. subtilis and B. thuringiensis are now becoming a reality. Many species have advantages for certain industrial applications, such as the lack of alkaline proteases, stable plasmid maintenance, and production of thermostable enzymes. It is now possible to increase production levels in many Bacillus strains that are already high producers of amylases, proteases, penicillinases, and penicillin amidases, by the introduction of such genes on high-copy-number plasmids. Possible problems in gene regulation, expression, limits on protein production, and secretion will be encountered, but recent reports on comparisons of expression of bacterial and eukaryotic genes in B. subtilis and B. megaterium (Shivakumar et al. 1989; Donovan et al. 1989a, 1989c; Ginsburgh et al. 1989) suggest that some species may prove to be better expression hosts for specific genes than others. What is needed is extensive comparative studies in promising species to better understand the parameters affecting cloning, gene expression, and protein secretion in the bacilli. In this chapter we have emphasized the development of genetic analysis and rDNA methods in B. megaterium. While the chromosomal map is still not a complete circle, many gene loci have been mapped, some with three-factor crosses, and have been characterized by enzyme assays (leu, trp, hem, cob, cbl) as well as complementation with B. subtilis genes (trp, dnaK, pur, met, ssp) E. coli genes (ATPase), hybridization (spoVG, abrB, sigK, ssp), and by growth on intermediates (trp, leu, thy, gua, ade, pur, pyr, his, arg). A mapping kit of 12 strains is available, and can facilitate the mapping of new mutations rapidly. This is of great advantage in strain construction since genes can be transferred at will by cotransduction. A partial physical map generated by pulse gel electrophoresis is also available (Muse 1990). It remains to be determined whether gene conversion occurs in B. megaterium as it does in B. subtilis. This is a powerful tool for rescuing genes and mutations of interest from the chromosome. There are now over 600 mutants available in our laboratory, over 100 in the laboratory of J.C. Vary, and several more that have been characterized in various laboratories throughout the world. Many of these are available in stock culture collections, although this source needs to be expanded. Mutants that should be useful for genetic engineering include recombination negative, protease negative, and plasmidless wild type, as well as Lac negative and several auxotrophs in the plasmidless background, and many sporulation negative mutants.

Bacillus megaterium↗

PubMed1993

V79 Chinese hamster cells genetically engineered for cytochrome P450 and their use in mutagenicity and metabolism studies.

V79 Chinese hamster cells are being genetically engineered for stable expression of cytochromes P450 using a SV40 early promoter containing plasmid as the eukaryotic expression vector. V79 cells lack endogenous cytochrome P450 activity. Therefore, genetically engineered V79 cell lines are defined for the cytochrome P450 isoform acquired upon cDNA mediated gene transfer. V79 cells have a longstanding tradition as indicator cells for various biological endpoints, e.g. mutation, chromosomal aberration, cytotoxicity. The genetically engineered V79 cells combine these useful biological endpoints with metabolic competence. In this sense, V79 cell lines genetically engineered for stable expression of cytochromes P450 present newly developed tools for studying and understanding metabolism related problems in toxicology and pharmacology.

Animals↗

PubMed2005

Breakthrough in chloroplast genetic engineering of agronomically important crops.

Chloroplast genetic engineering offers several unique advantages, including high-level transgene expression, multi-gene engineering in a single transformation event and transgene containment by maternal inheritance, as well as a lack of gene silencing, position and pleiotropic effects and undesirable foreign DNA. More than 40 transgenes have been stably integrated and expressed using the tobacco chloroplast genome to confer desired agronomic traits or express high levels of vaccine antigens and biopharmaceuticals. Despite such significant progress, this technology has not been extended to major crops. However, highly efficient soybean, carrot and cotton plastid transformation has recently been accomplished through somatic embryogenesis using species-specific chloroplast vectors. This review focuses on recent exciting developments in this field and offers directions for further research and development.

Crops, Agricultural↗

PubMed1995

Genetic engineering of vein grafts resistant to atherosclerosis.

Previously, researchers have speculated that genetic engineering can improve the long-term function of vascular grafts which are prone to atherosclerosis and occlusion. In this study, we demonstrated that an intraoperative gene therapy approach using antisense oligodeoxynucleotide blockage of medial smooth muscle cell proliferation can prevent the accelerated atherosclerosis that is responsible for autologous vein graft failure. Selective blockade of the expression of genes for two cell cycle regulatory proteins, proliferating cell nuclear antigen and cell division cycle 2 kinase, was achieved in the smooth muscle cells of rabbit jugular veins grafted into the carotid arteries. This alteration of gene expression successfully redirected vein graft biology away from neointimal hyperplasia and toward medial hypertrophy, yielding conduits that more closely resembled normal arteries. More importantly, these genetically engineered grafts proved resistant to diet-induced atherosclerosis. These findings establish the feasibility of developing genetically engineered bioprostheses that are resistant to failure and better suited to the long-term treatment of occlusive vascular disease.

Animals↗

PubMed2004

Genetic engineering and the moral status of non-human species.

Genetic modification leads to several important moral issues. Up until now they have been discussed from the viewpoint that only individual living beings, above all animals, are morally considerable. The standpoint that also collective entities such as species belong to the moral sphere have seldom been taken into account in a more thorough way, although it is advocated by several important environmental ethicists. The main purpose of this article is to analyze in more detail than often has been done what the practical consequences of this ethical position would be for the use of genetic engineering on animals and plants. The practical consequences of the holistic standpoint (focused on collective entities) of Holmes Rolson, III, is compared with the practical consequences of the individualistic standpoints (focused on individual living beings) of Bernard E. Rollin and Philipp Balzer, Klaus Peter Rippe, and Peter Schaber, respectively. The article also discusses whether the claim that species are morally considerable is tenable as a foundation for policy decisions on genetic engineering.

Animals↗

PubMed1998

Continuous delivery of human and mouse erythropoietin in mice by genetically engineered polymer encapsulated myoblasts.

The transplantation of polymer encapsulated myoblasts genetically engineered to secrete erythropoietin (Epo) may obviate the need for repeated parenteral administration of recombinant Epo as a treatment for chronic renal failure, cancer or AIDS-associated anemia. To explore this possibility, the human and mouse Epo cDNAs under the control of the housekeeping mouse PGK-1 promoter were transfected into mouse C2C12 myoblasts, which can be terminally differentiated upon exposure to low serum-containing media. Pools releasing 150 IU human Epo per 10(6) cells per day and 390 IU mouse Epo per 10(6) cells per day were selected. Polyether-sulfone (PES) capsules loaded with approximately 200,000 transfected myoblasts from these pools were implanted on the dorsal flank of DBA/2J, C3H and C57BL/6 mice. With human Epo secreting capsules, only a transient increase in the hematocrit occurred in DBA/2J mice, whereas no significant response was detected in C3H or C57BL/6 mice. On the contrary, all mice implanted with capsules releasing mouse Epo increased their hematocrit over 85% as early as 7 days after implantation and sustained these levels for at least 80 days. All retrieved implants released Epo and contained well preserved myoblasts. Moreover most capsules were surrounded by a neovascularization. Mice transplanted with nonencapsulated C2C12 cells releasing mouse Epo showed only a transitory elevation of their hematocrit reflecting the poor engraftment of injected myoblasts. These results indicate that polymer encapsulation of genetically engineered myoblasts is a promising approach for the long-term delivery of bioactive molecules, allowing the resolution of the shortcomings of free myoblast transfer.

Acquired Immunodeficiency Syndrome↗

PubMed1997

Ecological and evolutionary physiology of heat shock proteins and the stress response in Drosophila: complementary insights from genetic engineering and natural variation.

Classical adaptational and genetic engineering approaches offer complementary insights to understanding biological variation: the former elucidates the origins, magnitude and ecological context of natural variation, while the latter establishes which genes can underlie natural variation. Studies of the stress or heat shock response in Drosophila illustrate this point. At the cellular level, heat shock proteins (Hsps) function as molecular chaperones, minimizing aggregation of peptides in non-native conformations. To understand the adaptive significance of Hsps, we have characterized thermal stress that Drosophila experience in nature, which can be substantial. We used these findings to design ecologically relevant experiments with engineered Drosophila strains generated by unequal site-specific homologous recombination; these strains differ in hsp70 copy number but share sites of transgene integration. hsp70 copy number markedly affects Hsp70 levels in intact Drosophila, and strains with extra hsp70 copies exhibit corresponding differences in inducible thermotolerance and reactivation of a key enzyme after thermal stress. Elevated Hsp70 levels, however, are not without penalty; these levels retard growth and increase mortality. Transgenic variation in hsp70 copy number has counterparts in nature: isofemale lines from nature vary significantly in Hsp70 expression, and this variation is also correlated with both inducible thermotolerance and mortality in the absence of stress.

Animals↗