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At least 649 records · Page 36Linked to original sources
PubMed1999

Metal working fluid-associated hypersensitivity pneumonitis: an outbreak investigation and case-control study.

Occupational exposure to bacterial or fungal antigens has been associated with hypersensivity pneumonitis (HP), an immunologically-mediated pulmonary disease. Between August 1995 and April 1996, 34 employees working in machining and assembly areas of an engine manufacturing plant were clinically diagnosed with HP. Of these, 20 employees met an epidemiologic case definition. In a case-control study, no exposure variables, including duration and intensity of metal working fluid (MWF) exposure, were statistically associated with an increased risk of disease. Neither cases nor controls demonstrated precipitin reactivity against unused samples of the seven MWF and two biocides used in the plant. HP cases had a significantly higher prevalence of positive precipitin reactions to used oil soluble and synthetic MWFs. Reactivity to used but not unused MWF suggests a biocontaminant, probably bacteria or fungi, is the causative antigen in the development of HP in this setting.

Alveolitis, Extrinsic Allergic↗
PubMed1984

An Agrobacterium-transformed cell culture from the monocot Asparagus officinalis.

Cultured stem fragments from the monocotyledonous plant Asparagus officinalis infected by the oncogenic bacterium Agrobacterium tumefaciens developed tumorous proliferations. This tissue was propagated in vitro on hormone-free culture medium. The T-DNA-encoded markers nopaline and agrocinopine were unambiguously detected in these tissues. The data demonstrate that stable T-DNA transfer as well as expression of T-DNA genes is possible in at least some monocotyledonous plants. This opens new possibilities for plant genetic engineering using the Ti plasmid as a gene vector.

Journal Article↗
PubMed1991

[Contribution to the discussion on the release of transgenic organisms. II. Ecologic aspects].

Problems which might be caused by the release of transgenic organisms are discussed from the viewpoint of genetics, population genetics and ecology. On this background, the differences between "classical" methods to recombine genetic information and the more recent ones of gene engineering are pointed out and the predictability of gene interactions is discussed. Moreover, the possibility of uncontrolled reproduction of released transgenic organisms and the distribution of manipulated genes are demonstrated on the basis of our knowledge on nontransgenic organisms. Finally, the problems of risk assessment are emphasized.

Ecology↗
PubMed1991

[Contribution by discussion on the release of transgenic organisms. I. Genetic aspects].

Problems which might be caused by the release of transgenic organisms are discussed from the viewpoint of genetics, population genetics and ecology. On this background, the differences between "classical" methods to recombine genetic information and the more recent ones of gene engineering are pointed out and the predictability of gene interactions is discussed. Moreover, the possibility of uncontrolled reproduction of released transgenic organisms and the distribution of manipulated genes are demonstrated on the basis of our knowledge on nontransgenic organisms. Finally, the problems of risk assessment are emphasized.

Genetic Engineering↗
PubMed1993

Nature in the laboratory--nature as a laboratory. Considerations about the ethics of release experiments.

Field tests with genetically modified organisms go beyond the boundaries of the politically and morally neutralized space that normally surrounds scientific experiments. They enter public areas. As a social process of shaping nature they are political in a fundamental sense. Consequences of this observation concern the legitimacy of decisions and the legitimacy of deciding procedures. The political rights of citizens and their human rights can only be respected if these procedures are democratic. Without a more serious exploration of the specific circumstances of release tests--for example, the precise ecological context, the consequences for the future development of the affected ecosystem, the social consequences, and the possible institutional ways of establishing gene technology in agriculture--we do not really know what we are doing when we release transgenic organisms. Moral judgements today can therefore only be prima facie, not free from shortcomings. As responsible judges we must confess that we are still morally blind.

Containment of Biohazards↗
PubMed2002

Genetic modification of lignin concentration affects fitness of perennial herbaceous plants.

Populations of four perennial herbaceous species that were genetically modified for altered lignin content (or associated forage digestibility) by conventional plant breeding were evaluated for two agricultural fitness traits, plant survival and plant biomass, in three Northcentral USA environments for more than 4 years. Reduced lignin concentration or increased digestibility resulted in increased winter mortality in two of four species and reduced biomass in one species. Results from other experiment indicate that these apparent genetic correlations may be ephemeral, suggesting that selection for fitness can be successful within high-digestibility or low-lignin germplasm. Results indicate that perennial plants genetically engineered with altered lignin concentration or composition for use in livestock, pulp and paper, or bioenergy production should be evaluated for fitness in field environments prior to use in agriculture.

Journal Article↗
PubMed2001

Biosensors as new analytical tool for detection of Genetically Modified Organisms (GMOs).

Three different biosensors for detection of Genetically Modified Organisms (GMOs) are presented. The sensing principle is based on the affinity interaction between nucleic acids: the probe is immobilised on the sensor surface and the target analyte is free in solution. The immobilised probes are specific for most inserted sequences in GMOs: the promoter P35S and the terminator TNOS. Electrochemical methods with screen-printed electrodes, piezoelectric and optical (SPR) transduction principles were applied.

Biosensing Techniques↗
PubMed2006

Transgenic Medicago truncatula plants obtained from Agrobacterium tumefaciens -transformed roots and Agrobacterium rhizogenes-transformed hairy roots.

Medicago truncatula, barrel medic, is a forage crop that has been developed into a model legume. The development of new transformation methods is important for functional genomic studies in this species. Based on Agrobacterium tumefaciens-mediated transformation of root explants, we developed an effective system for producing M. truncatula (genotype R108) transgenic plants. Among the four A. tumefaciens strains (AGL1, C58C1, EHA105 and LBA4404) tested, EHA105 and AGL1 were most effective in regenerating transgenics. Callus induction frequency from root explants was 69.8%, and plantlet/shoot regeneration frequency was 41.3% when EHA105 was used. Transgenic nature of the regenerated plants was confirmed by PCR and Southern hybridization analyses. Progeny analysis revealed stable Mendelian meiotic transmission of transgenes. Because M. truncatula is particularly useful for the study of root endosymbiotic associations, we further developed a plant regeneration system from A. rhizogenes-transformed hairy roots of M. truncatula. Fertile true transgenic plants were regenerated from the hairy roots, thus allowing the assessment of gene functions at the whole plant level. Segregation analysis revealed that the hairy root genes could be segregated out in the progenies. By coupling A. rhizogenes-mediated hairy root transformation and the regeneration system reported here, once potential genes of interest are identified, the transformed hairy roots carrying such genes could be directly regenerated into plants for more detailed characterization of the genes.

Acetyltransferases↗
PubMed2000

Transgene repeats in aspen: molecular characterisation suggests simultaneous integration of independent T-DNAs into receptive hotspots in the host genome.

Rearrangements of T-DNAs during genetic transformation of plants can result in the insertion of transgenes in the form of repeats into the host genome and frequently lead to loss of transgene expression. To obtain insight into the mechanism of repeat formation we screened 45 transgenic lines of aspen and hybrid aspen transformed with six different gene constructs. The frequency of T-DNA repeat formation among randomly screened transgenic lines was found to be about 21%. In ten transgenic lines direct repeats were detected. An inverted repeat was found in one other transgenic line. Sequencing of the junctions between the T-DNA inserts revealed identical residual right-border repeat sequences at the repeat junctions in all ten transgenic lines that had direct repeats. Formation of "precise" junctions based on short regions of sequence similarity between recombining strands was observed in three transgenic lines transformed with the same plasmid. Additional DNA sequences termed filler DNAs were found to be inserted between the T-DNA repeats at eight junctions where there was no similarity between recombining ends. The length of the filler DNAs varied from 4 to almost 300 bp. Small filler DNAs--a few base pairs long--were in most cases copied from T-DNA near the break points. The large filler sequences of about 300 bp in two transgenic lines were found to be of host plant origin, suggesting that transgene repeat formation occurred as a result of the simultaneous invasion of a receptive site in the host genome by two independent T-DNA strands. On the basis of the results obtained, and in the light of previous reports on T-DNA/plant DNA junctions in aspen and other crop plants, a mechanistic model for transgene rearrangement and filler formation is suggested.

Agrobacterium tumefaciens↗
PubMed2006

Tobacco protoplast culture in a polydimethylsiloxane-based microfluidic channel.

Several advances have been made in the use of microfluidic devices for insect and mammalian cell cultures, but no reports of their use for plant cell cultures have been published. We, therefore, conducted a plant cell culture in a microfluidic device using polydimethylsiloxane. Nicotiana tabacum protoplasts were cultured in a variously shaped polydimethylsiloxane channel containing Nitsch medium supplemented with 0.5 g of NLN-13 vitamin mixture, 2.0 mg of alpha-naphthaleneacetic acid, and 0.5 mg of 6-benzyladenine per liter and 9% mannitol. Protoplasts in the polydimethylsiloxane channel showed cell division and microcolony formation within 4 weeks. The use of a microfluidic channel is a novel technique in the field of plant cell culture. The results of this study will encourage the utilization of polydimethylsiloxane-based microfluidic devices in plant cell engineering and cell analysis.

Cell Culture Techniques↗
PubMed2005

Immunogenic properties of a chimeric plant virus expressing a hepatitis C virus (HCV)-derived epitope: new prospects for an HCV vaccine.

A vaccine against Hepatitis C virus (HCV) is urgently needed due to the unsatisfactory clinical response to current therapies. We evaluated the immunological properties of a chimeric Cucumber mosaic virus (CMV), a plant virus engineered to express on its surface a synthetic peptide derived from many HVR1 sequences of the HCV envelope protein E2 (R9 mimotope). Evidence was obtained that the chimeric R9-CMV elicits a specific humoral response in rabbits. Furthermore, in patients with chronic HCV infection, purified preparations of R9-CMV down-modulated the lymphocyte surface density of CD3 and CD8, and induced a significant release of interferon (IFN)-gamma, interleukin (IL)-12 p70 and IL-15 by lymphomonocyte cultures. Finally, an R9 mimotope-specific CD8 T-cell response, as assessed by intracellular IFN-gamma production, was achieved in the majority of the patients studied. Our results open up new prospects for the development of effective vaccines against HCV infection. Moreover, the wide edible host range of CMV makes the production of an edible vaccine conceivable.

Adult↗
PubMed1983

Construction of a broad-host-range kanamycin-resistant plasmid vector.

A new 10.2-kb plasmid, pIRL2, was constructed by using a 2140-bp DNA fragment carrying the Kmr gene and BamHI cohesive ends. These BamHI cohesive ends were used to trap the replicating DNA fragment from a partial Sau3A digest of the plasmid R300B. The plasmid contains unique EcoRI, SstI, HindIII, SmaI, SalI, and XhoI sites. These sites can be used as cloning sites without the loss of Kmr. A unique BglII site can be used as a cloning site by insertional inactivation of the Kmr structural gene, coding for neomycin phosphotransferase type II. The new plasmid carries the Sur and Smr genes of R300B. The direction of transcription from the neo promoter is clockwise, the same as that from the sul promoter. The plasmid retains the broad-host-range function of R300B, and thus it may be used for gene cloning in Rhizobium and Agrobacterium for genetic engineering of plant cells.

Cloning, Molecular↗
PubMed2004

Polyhydroxybutyrate synthesis in transgenic flax.

Flax (Linum usitatissimum L.) is an annual plant species widely cultivated in temperate climates for bast fibres and linseed oil. Apart from traditional textile use, the fibres are fast becoming an integral part of new composite materials utilized in automobile and constructive industry. Especially attractive for environmental safety demands are biodegradable and renewable biocomposities based on polyhydroxybutyrate (PHB) polymer as a matrix and reinforced with the flax fibres. Manufacturing of PHB by bacteria fermentation is however substantially more expansive as compared to technologies producing conventional plastics. We report for the first time generation of transgenic plants which produce both components of flax/PHB composites, i.e. the fibres and the thermoplastic matrix in the same plant organ of a crop. The flax (cv. Nike) plants were transformed using constructs bearing either single cDNA, encoding the beta-ketothiolase enzyme (C plants), or all three of the genes necessary for poly-beta-hydroxybutyrate (PHB) synthesis (M plants). Both constructs contained a plastidial targeting sequence. The amount of PHB produced by the transgenic plants was up to over 70-fold higher than in wild-type plants, when analysed using the gas chromatography/mass spectrometry (GC-MS method). The PHB accumulation in plastids caused change both in their shape and size. The use of a stem-specific promoter for transgene expression protected the transgenic plant from growth retardation and also provided higher PHB synthesis than in the case of constructs governed by the 35S CaMV constitutive promoter. None toxic effects that could lead to stunted growth or the loss of fertility were observed, when 14-3-3 promoter was used as the stem-specific. Significant modifications in stem mechanical properties were accompanied to the PHB accumulation in growing cell of fibres in the transgenic plants. The Young's modulus E, the average measure of stem tissues resistance to tensile loads increased up to twice in M plants as compared to a single gene transformed ones. However, a wide range of E values, from 24.1 to 54.4 MPa, was observed in dependence of tested strain. Potential commercial significance of the genetic manipulation approach enabling synthesis of thermoplastic in crops cultivated for fibres is discussed.

Carbohydrate Metabolism↗