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  • 1
    Electronic Resource
    Electronic Resource
    Keeping Up with the Cloneses -- Issues in Human Cloning (1999)
    Springer
    The journal of ethics 3 (1999), S. 51-71 
    Details
    ISSN: 1572-8609
    Keywords: biotechnology ; cloning ; ethics of biotechnology ; ethics of cloning ; ethics of human cloning ; ethics for reproductive technology ; genetic engineering ; human cloning ; religious ethics ; reproductive technology ; secular ethics ; social ethics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Philosophy
    Notes: Abstract The advent of cloning animals has created a maelstrom of social concern about the “ethical issues” associated with the possibility of cloning humans. When the “ethical concerns” are clearly examined, however, many of them turn out to be less matters of rational ethics than knee-jerk emotion, religious bias, or fear of that which is not understood. Three categories of real and spurious ethical concerns are presented and discussed: 1) that cloning is intrinsically wrong, 2) that cloning must lead to bad consequences, and 3) that cloning harms the organism generated. The need for a rational ethical framework for discussing biotechnological advances is presented and defended.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009775715165
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  • 2
    Electronic Resource
    Electronic Resource
    A Modular Vector for Agrobacterium Mediated Transformation of Wheat (1999)
    Springer
    Plant molecular biology reporter 17 (1999), S. 323-331 
    Details
    ISSN: 1572-9818
    Keywords: Agrobacterium ; modular vector ; transformation ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Wheat (cv Chinese Spring) tissues were transformed using Agrobacterium tumefasciens and a new plasmid modular vector, pMVTBP. We constructed pMVTBP with unique restriction sites connecting (1) the CaMV 35S promoter, (2) a Kozak sequence, (3) the FLAG epitope, (4) the (His)6 epitope, (5) a coding region (for wheat TATA Binding Protein, wTBP) and (6) the CaMV 35S 3′UTR. This vector thus allows easy exchange of different regulatory or coding sequences. Explants of either germinating mature seeds, or immature embryos, were induced to callus for up to two weeks, treated with virulence-induced bacteria for one hour, then regenerated into plantlets. Transient expression of a GUS reporter gene, assayed at about one week, occurred in 10–12% of calluses. Expression of the FLAG-tagged wTBP was also detected, by immunostaining. Stable expression, by selective growth on geneticin, and by GUS expression at about six weeks, occurred in 1–2% of calluses, quite comparable to that achieved by other methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007686408369
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  • 3
    Electronic Resource
    Electronic Resource
    Transgenic almond (Prunus dulcis Mill.) plants obtained by Agrobacterium-mediated transformation of leaf explants (1999)
    Springer
    Plant cell reports 18 (1999), S. 387-393 
    Details
    ISSN: 1432-203X
    Keywords: Key words Almond ; Prunus ; Transformation ; Agrobacterium ; Adventitious regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Almond (Prunus dulcis Mill.) leaves were transformed with the marker genes gusA (β-glucuronidase) and nptII (neomycin phosphotransferase II) via Agrobacterium-mediated transformation. Bacterial strains and preculture of explants affected efficiency of gene transfer evaluated by transient expression assays. Following transformation, shoots were induced from primary explants on medium without kanamycin and exposed to selection 20 days after cocultivation. From 1419 original leaves, four shoots (A, B, C and D) were obtained that showed amplification of the predicted DNA fragments by polymerase chain reaction (PCR). After micropropagation of these shoots, only those cloned from shoot D gave consistently positive results in histochemical GUS detection and PCR amplification. Southern blot hybridisation confirmed stable transgene integration in clone D, which was also negative in PCR amplification of an Agrobacterium gene. Additional molecular analysis suggested that the remaining three shoots (A, B and C) were chimeric.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002990050591
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  • 4
    Electronic Resource
    Electronic Resource
    Green-fluorescent protein facilitates rapid in vivo detection of genetically transformed plant cells (1999)
    Springer
    Plant cell reports 18 (1999), S. 707-714 
    Details
    ISSN: 1432-203X
    Keywords: Key words Green-fluorescent protein ; Transformation ; Particle bombardment ; Agrobacterium ; Sugarcane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Early detection of plant transformation events is necessary for the rapid establishment and optimization of plant transformation protocols. We have assessed modified versions of the green fluorescent protein (GFP) from Aequorea victoria as early reporters of plant transformation using a dissecting fluorescence microscope with appropriate filters. Gfp-expressing cells from four different plant species (sugarcane, maize, lettuce, and tobacco) were readily distinguished, following either Agrobacterium-mediated or particle bombardment-mediated transformation. The identification of gfp-expressing sugarcane cells allowed for the elimination of a high proportion of non-expressing explants and also enabled visual selection of dividing transgenic cells, an early step in the generation of transgenic organisms. The recovery of transgenic cell clusters was streamlined by the ability to visualize gfp-expressing tissues in vitro.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002990050647
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  • 5
    Electronic Resource
    Electronic Resource
    Stable genetic transformation of white pine (Pinus strobus L.) after cocultivation of embryogenic tissues with Agrobacterium tumefaciens (1999)
    Springer
    Molecular breeding 5 (1999), S. 429-440 
    Details
    ISSN: 1572-9788
    Keywords: transgenic trees ; scaffold attachment region ; Agrobacterium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A genetic transformation procedure for white pine has been developed after cocultivation of embryogenic tissues with Agrobacterium tumefaciens. This efficient transformation procedure led to an average of four independent transformed lines per gram of cocultivated embryogenic tissue and up to 50 transformed lines can be obtained in a routine experiment. Constructs bearing the uidA gene or the green fluorescent protein (GFP) gene were introduced and β-glucuronidase (GUS) activity was followed over time. The expression of the uidA gene was lowest with a 35S-gus-intron construct and was 20-fold higher with a 35S-35S-AMVgus::nptII construct. The addition of scaffold attachment region (SAR) sequences surrounding the gus::nptII fusion did not significantly enhance the GUS activity. Transformed mature somatic embryos have been germinated and plantlets are presently being acclimatized.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009683605841
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  • 6
    Electronic Resource
    Electronic Resource
    Wounding by bombardment yields highly efficient Agrobacterium-mediated transformation of carnation (Dianthus caryophyllus L.) (1999)
    Springer
    Molecular breeding 5 (1999), S. 367-375 
    Details
    ISSN: 1572-9788
    Keywords: transgenic carnation ; genetic engineering ; microprojectile bombardment ; stable transformation ; kanamycin selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Highly efficient Agrobacterium-mediated transformation of carnation (Dianthus caryophyllus L.) was obtained by first wounding stem explants via microprojectile bombardment. When this was followed by cocultivation with disarmed Agrobacterium in the dark, the transformation frequency-based on transient GUS expression-increased to over 10-fold that of explants wounded by other means and cocultivated under constant light. Two cycles of regeneration/selection on kanamycin were employed to generate stably transformed carnation plants and eliminate chimeras: first, plantlets were regenerated from inoculated stem explants and then leaves from these plantlets were used to generate transgenes in a second selection cycle of adventitious shoot regeneration. Agrobacterium strain AGLO, carrying the binary vector pCGN7001 containing uidA and nptII genes, was used in the stable transformation experiments. The combination of wounding via bombardment, cocultivation in the dark and two cycles of kanamycin selection yielded an overall transformation efficiency of 1–2 transgenes per 10 stem explants for the three carnation varieties analyzed. Histochemical and molecular analyses of marker genes in T0 and T1 generations confirmed the transgenic nature of the selected plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009671131200
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  • 7
    Electronic Resource
    Electronic Resource
    Positive-negative selection and T-DNA stability in Arabidopsis transformation (1999)
    Springer
    Plant molecular biology 39 (1999), S. 83-93 
    Details
    ISSN: 1573-5028
    Keywords: Arabidopsis ; Agrobacterium ; T-DNA ; CodA ; positive-negative selection ; recombination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have analysed the application of positive-negative selection for the selection of homologous recombination interactions between the chromosome and a T-DNA molecule after transformation of plant cells. Two different genomic loci in a cell suspension of Arabidopsis thaliana were chosen to study gene targeting events. One was the chalcone synthase (CHS) gene present as a single copy and the second an hemizygous chromosomally inserted T-DNA containing the hpt gene, conferring resistance to hygromycin, flanked by CHS sequences. The target lines were transformed with replacement-type T-DNA vectors which contained a positive selectable marker flanked by the regions of the CHS gene and a negative selectable marker to counter-select random insertions. As negative marker we used the Escherichia coli codA gene encoding cytosine deaminase, conferring upon the cells sensitivity to 5-flourocytosine (5-FC). Doubly selected transformants represent 1–4% of the primary transformed cells. Targeting events were not found at the chalcone synthase locus nor at the artificial hpt locus in a total of 4379 doubly selected calli, corresponding to at least 109 475 individual primary transformants. We show by PCR and Southern analysis that the 5-FC resistance in the majority of these cells is associated with substantial deletions of the T-DNA molecule from the right-border end.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006192225464
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  • 8
    Electronic Resource
    Electronic Resource
    Genetic engineering of shikonin biosynthesis hairy root cultures of Lithospermum erythrorhizon transformed with the bacterial ubiC gene (1999)
    Springer
    Plant molecular biology 39 (1999), S. 683-693 
    Details
    ISSN: 1573-5028
    Keywords: genetic engineering ; 4-hydroxybenzoic acid glucoside ; Lithospermum erythrorhizon ; menisdaurin ; shikonin ; ubiC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The biosynthetic pathway to 4-hydroxybenzoate (4HB), a precursor of the naphthoquinone pigment shikonin, was modified in Lithospermum erythrorhizon hairy root cultures by introduction of the bacterial gene ubiC. This gene of Escherichia coli encodes chorismate pyruvate-lyase (CPL), an enzyme that converts chorismate into 4HB and is not normally present in plants. The ubiC gene was fused to the sequence for a chloroplast transit peptide and placed under control of a constitutive plant promoter. This construct was introduced into L. erythrorhizon by Agrobacterium rhizogenes-mediated transformation. The resulting hairy root cultures showed high CPL activity. 4HB produced by the CPL reaction was utilized for shikonin biosynthesis, as shown by in vivo inhibition of the native pathway to 4HB with 2-aminoindan-2-phosphonic acid (AIP), an inhibitor of phenylalanine ammonia-lyase. A feeding experiment with [1,7-13C2]shikimate showed that in the absence of AIP the artificially introduced CPL reaction contributed ca. 20% of the overall 4HB biosynthesis in the transgenic cultures. ubiC transformation did not lead to a statistically significant increase of shikonin formation, but to a 5-fold increase of the accumulation of menisdaurin, a nitrile glucoside which is presumably related to aromatic amino acid metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006185806390
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  • 9
    Electronic Resource
    Electronic Resource
    Sequence and functional analysis of the left-hand part of the T-region from the nopaline-type Ti plasmid, pTiC58 (1999)
    Springer
    Plant molecular biology 41 (1999), S. 765-776 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium ; Ti plasmid ; oncogenes ; e gene ; 3′ gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Agrobacterium tumefaciens nopaline strain C58 transfers a large, 29 kb T-DNA into plant cells during infection. Part of this DNA (the `common DNA') is also found on the T-DNA of octopine strains, the remaining DNA is nopaline strain-specific. Up to now, only parts of the C58 T-DNA and related T37 T-DNA have been sequenced. We have sequenced the remainder of the nopaline-specific T-DNA (containing genes a to d) and acs to iaaM. Gene c codes for a new unknown T-DNA protein. Gene a is homologous to the agrocinopine synthase gene. Genes b, c′, d and e are part of a larger family: they are related to the T-DNA genes 5, rolB, lso and 3′. Genes 5, rolB and lso induce or modify plant growth and have been called T-DNA oncogenes. Our studies show that gene 3′ (located on the TR-DNA of octopine strains) is also oncogenic. Although the b–e T-DNA fragment from C58 and its individual genes lack growth-inducing activity, an a-acs deletion mutant was distinctly less virulent on Kalanchoe daigremontiana and showed reduced shoot formation on Kalanchoe tubiflora. Shoot formation could be restored by genes c and c′ in co-infection experiments. Contrary to an earlier report, a C58 e gene deletion mutant was fully virulent on all plants tested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006370207379
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  • 10
    Electronic Resource
    Electronic Resource
    Questions about the complexity of chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase (1999)
    Springer
    Photosynthesis research 60 (1999), S. 29-42 
    Details
    ISSN: 1573-5079
    Keywords: enzyme catalysis ; evolution ; genetic engineering ; photosynthesis ; protein assembly ; protein degradation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco; EC 4.1.1.39) has played a central role in our understanding of chloroplast biogenesis and photosynthesis. In particular, its catalysis of the rate-limiting step of CO2 fixation, and the mutual competition of CO2 and O2 at the active site, makes Rubisco a prime focus for genetically engineering an increase in photosynthetic productivity. Although it remains difficult to manipulate the chloroplast-encoded large subunit and nuclear-encoded small subunit of crop plants, much has been learned about the structure/function relationships of Rubisco by expressing prokaryotic genes in Escherichia coli or by exploiting classical genetics and chloroplast transformation of the green alga Chlamydomonas reinhardtii. However, the complexity of chloroplast Rubisco in land plants cannot be completely addressed with the existing model organisms. Two subunits encoded in different genetic compartments have coevolved in the formation of the Rubisco holoenzyme, but the function of the small subunit remains largely unknown. The subunits are posttranslationally modified, assembled via a complex process, and degraded in regulated ways. There is also a second chloroplast protein, Rubisco activase, that is responsible for removing inhibitory molecules from the large-subunit active site. Many of these complex interactions and processes display species specificity. This means that attempts to engineer or discover a better Rubisco may be futile if one cannot transfer the better enzyme to a compatible host. We must frame the questions that address this problem of chloroplast-Rubisco complexity. We must work harder to find the answers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006240202051
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  • 11
    Electronic Resource
    Electronic Resource
    Evidence of Migration and Endophytic Presence of Agrobacterium tumefaciens in Rose Plants (1999)
    Springer
    European journal of plant pathology 105 (1999), S. 39-50 
    Details
    ISSN: 1573-8469
    Keywords: Agrobacterium ; crown gall ; systemic infection ; rose ; endophyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Agrobacterium tumefaciens was isolated from stem tumors of several rose cultivars showing that the bacterium is the causal agent of aerial galls in rose plants. No differences were observed in the characteristics of the Agrobacterium isolates from crown or aerial galls. Stem inoculation of ten rose cultivars showed that all of them were susceptible to A. tumefaciens but differences in the size of the resulting tumors were observed. The movement of A. tumefaciens in rose plants was demonstrated using two wild type strains and two antibiotic resistant mutants. Three months after inoculation, the inoculated strains were recovered in the roots, crown and below and above the inoculation site but low numbers of pathogenic Agrobacterium cells were isolated. New tumors appeared in 5% of the noninoculated wounds. A. tumefaciens was isolated from the stem at different distances from the tumor in naturally infected plants. In symptomless commercial plants, the isolation from the roots, crown and at different stem levels demonstrated the existence of systemic and latent infections in rose. Direct isolation using a nonselective and selective media with or without a previous enrichment step were efficient methods for isolating tumorigenic Agrobacterium from the different parts of rose plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008660500107
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  • 12
    Electronic Resource
    Electronic Resource
    Origin and evolution of plasmids (1998)
    Springer
    Antonie van Leeuwenhoek 73 (1998), S. 117-126 
    Details
    ISSN: 1572-9699
    Keywords: riboplasmids ; encapsidation ; pseudovirions ; selfish plasmids ; replicons ; ribozyme ; Agrobacterium ; Rhizobium ; grapevines ; L-tartrate ; lignin ; methoxyphenols ; satellite viruses ; opines ; crown gall ; T-DNA ; origin of replication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Studies on the origin and evolution of plasmids may provide valuable insights on the promiscuous nature of DNA. The first examples of the selfish nature of nucleic acids are exemplified by primordial oligoribonucleotides which evolved into primitive replicons. The propagation of these molecules were likely patterned after the current viral RNA ribozymes, which have been recently shown to possess RNA synthesizing and template mediated polymerizing capabilities in the absence of proteins. The parasitic nature of nucleic acids is depicted by satellite nucleic acid molecules associated with viruses. The satellites of adenovirus and tobacco ringspot virus serve as established examples: they contain no open reading frames. Comparative analysis of the replication origins of virions and plasmids show them to be conserved, originating from the simplest autocatalytic replicon to highly complex and evolved plasmids, replicating by a rolling circle mechanism. The eventual association of proteins with nucleic acids provided added efficiency and protective advantages for molecular perpetuation. The promiscuous and selfish nature of plasmids is demonstrated by their ability to genetically engineer their host so that the host cell is best able to cope and survive in hostile environments. Survival of the host ensures survival of the plasmid. Sequestering of genes by plasmids occurs when the environmental conditions negatively affect the host. The sequestering mechanism is fundamental and forms the outreach mechanisms to generate and propagate macromolecules of increasing size when necessary for survival. The level of sophistication of plasmids increases with the addition of new genes such as those that allow the host to occupy a specific environment normally inhospitable to the host cell. The vast range of plasmid types which have obtained genes interchangeably reflect the levels of sophistication achieved by these macromolecules. The Ti plasmid in Agrobacterium tumefaciens and the pSym and accessory plasmids in Rhizobium illustrate the level of complexity attained by replicons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1000652513822
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  • 13
    Electronic Resource
    Electronic Resource
    Transformation and regeneration of Lobelia erinus using Agrobacterium tumefaciens (1998)
    Springer
    Plant cell reports 18 (1998), S. 308-311 
    Details
    ISSN: 1432-203X
    Keywords: Key words Campanulaceae ; Lobelia erinus ; Transformation ; Agrobacterium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A transformation/regeneration system was developed for the common garden Lobelia (Lobelia erinus). Using an Agrobacterium-based protocol, over 40 transformants have been generated with four different binary vectors. The explant source was hypocotyl-root sections from axenically grown seedlings. Stable transformation was demonstrated by Southern hybridization analysis, β-glucuronidase staining, and transmission of the T-DNA to progeny. This extends the ever-widening range of transformable plant species to the Campanulaceae and will allow molecular studies of development and physiology in this easily cultured and popular garden plant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002990050577
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  • 14
    Electronic Resource
    Electronic Resource
    Factors affecting soybean cotyledonary node transformation (1998)
    Springer
    Plant cell reports 18 (1998), S. 180-186 
    Details
    ISSN: 1432-203X
    Keywords: Key words Soybean ; SAAT (sonication assisted Agrobacterium-mediated transformation) ; Agrobacterium ; Transformation ; KYRT1
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cotyledonary node transformation efficiency was evaluated using a sonication assisted Agrobacterium-mediated transformation (SAAT) protocol, three dissimilar A. tumefaciens strains, and explants derived from 28 diverse cultivars and/or genotypes of soybean [Glycine max (L.) Merr.]. The explants were evaluated at 10 and 45 days after co-cultivation for transformation with a binary vector containing both a GUS-intron gene and an NPTII selectable marker. The best overall strain of A. tumefaciens was determined to be KYRT1 based on stable GUS transformation of soybean cotyledonary node explants measured at the terminal 45 day evaluation point. SAAT did not increase stable transformation at 45 days post co-cultivation. SAAT was determined to significantly decrease shoot proliferation of some genotypes, but it is unclear what effect this may have on the recovery of transformed shoots. Significant differences were also detected between genotypes for transformation and shoot proliferation frequency.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002990050553
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  • 15
    Electronic Resource
    Electronic Resource
    Transgenic peppermint (Mentha×piperita L.) plants obtained by cocultivation with Agrobacterium tumefaciens (1998)
    Springer
    Plant cell reports 17 (1998), S. 165-171 
    Details
    ISSN: 1432-203X
    Keywords: Key words Peppermint ; Transformation ; Agrobacterium ; GUS ; Transgenic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The first transgenic peppermint (Mentha×piperita L. cultivar Black Mitcham) plants have been obtained by Agrobacterium-mediated transformation by cocultivation with morphogenically responsive leaf explants. Basal leaf explants with petioles, from leaves closest to the apex of in-vitro-culture-maintained shoots (5 cm), exhibited optimal shoot organogenetic responsiveness on medium supplemented with thidiazuron (8.4 µm). Shoot formation occurred at sites of excision on the leaf blade and petiole either directly from cells of the explant or via a primary callus. Analyses of transient GUS activity data indicated that DNA delivery by microprojectile bombardment was more effective than Agrobacterium infection. However, no transgenic plants were obtained from over 22,000 leaf explants after particle bombardment. Cocultivation of leaf explants with Agrobacterium strain EHA 105 and kanamycin selection produced transgenic plants. Greater transient and stable -glucuronidase (GUS) activities were detected in explants or propagules transformed with the construct where gusA was driven by the pBISN1 promoter rather than a CaMV 35S promoter. Eight plants were subsequently regenerated and verified as transgenic based on detection of the nptII transgene by PCR and Southern blot analyses. The Southern analyses indicated that the plants were derived from eight unique transformation events. All transgenic plants appeared morphologically normal. Analyses of GUS activities in leaves sampled from different portions of these transgenic plants, 10 months after transfer to the greenhouse, indicated that six out of the eight original regenerants were uniformly transformed, i.e., did not exhibit chimeric sectors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002990050372
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  • 16
    Electronic Resource
    Electronic Resource
    Agrobacterium tumefaciens-mediated transformation of Eucalyptus camaldulensis and production of transgenic plants (1998)
    Springer
    Plant cell reports 17 (1998), S. 675-680 
    Details
    ISSN: 1432-203X
    Keywords: Key words Genetic transformation ; Agrobacterium ; Eucalyptus ; Regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An efficient system for Agrobacterium-mediated transformation of Eucalyptus camaldulensis and production of transgenic plants was developed. Transformation was accomplished by cocultivation of hypocotyl segments with Agrobacterium tumefaciens containing a binary Ti-plasmid vector harboring chimeric neomycin phosphotransferase and β-glucuronidase (GUS) genes. A modified Gamborg's B5 medium used in this study was effective for both callus induction and regeneration of transgenic shoots. This medium could also effectively maintain the organogenic capability of callus for more than a year. Culturing transgenic shoots in Murashige and Skoog medium supplemented with 0.1 mg ⋅ l–1 benzylaminopurine prior to root induction in rooting medium markedly increased the rootability of shoots that were recalcitrant to rooting. Histochemical assay revealed the expression of the GUS gene in leaf, stem, and root tissues of transgenic plants. Insertion of the GUS gene in the nuclear genome of transgenic plants was verified by genomic Southern hybridization analysis, further confirming the integration and expression of T-DNA in these plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002990050464
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  • 17
    Electronic Resource
    Electronic Resource
    Activity of the CaMV 35S promoter in various parts of transgenic early flowering birch clones (1998)
    Springer
    Plant cell reports 18 (1998), S. 243-248 
    Details
    ISSN: 1432-203X
    Keywords: Key wordsBetula pendula ; Transformation ; Agrobacterium ; Gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Early flowering together with small size would be useful for various biotechnical or genetic studies on trees. We report here the selection and micropropagation of early flowering birch (Betula pendula) clones (BPM1–12) obtained from seeds of birches bred elsewhere for early flowering. Under conditions that accelerate flowering (a high CO2 level, strong and continuous illumination), the first male inflorescences emerged in 3–5 months, the trees then being 20–80 cm high. Transgenic lines (CaMV 35S-GUS INT) were produced through Agrobacterium-mediated gene transfer from BPM2, BPM5 and JR1/4 (a normally flowering birch). β-Glucuronidase (GUS) activities in the different lines, assayed 1–1.5 years after transformation, varied greatly. During further in vitro culture for 10 months, the activities decreased to 0.3–7% of the original values. GUS activities were detected in all organs studied, including the developing male inflorescences; the highest activity was in the roots.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002990050564
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  • 18
    Electronic Resource
    Electronic Resource
    Transformation of arctic bramble (Rubus arcticus L.) by Agrobacterium tumefaciens (1998)
    Springer
    Plant cell reports 17 (1998), S. 822-826 
    Details
    ISSN: 1432-203X
    Keywords: Key words Rosaceae ; β-Glucuronidase ; Regeneration ; Agrobacterium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Genetic transformation of arctic bramble (Rubus arcticus L.) was achieved utilizing a Ti-plasmid vector system of Agrobacterium tumefaciens. Internodal stem segments were inoculated with Agrobacterium strain EHA101 carrying a T-DNA with the CaMV 35 S promoter-gus-int marker gene from which β-glucuronidase (GUS) is expressed only in plants. Regenerants were produced on Murashige and Skoog medium. Growth of Agrobacterium was inhibited with cefotaxime. Kanamycin was used as the selective agent for the transformants. Regenerants were assayed by histochemical GUS staining, and by Southern analysis using a gus-int probe. Transgenic arctic bramble plants containing gus-int and expressing GUS were recovered. Expression has been stable for 3 years in micropropagation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002990050491
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  • 19
    Electronic Resource
    Electronic Resource
    CaMV 35S promoter directs β-glucuronidase expression in the laticiferous system of transgenic Hevea brasiliensis (rubber tree) (1998)
    Springer
    Plant cell reports 17 (1998), S. 621-625 
    Details
    ISSN: 1432-203X
    Keywords: Key wordsHevea brasiliensis ; Agrobacterium ; CaMV 35S ; β-Glucuronidase ; Latex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Hevea brasiliensis anther calli were genetically transformed using Agrobacterium GV2260 (p35SGUSINT) that harboured the β-glucuronidase (gus) and neomycin phosphotransferase (nptII) genes. β-Glucuronidase protein (GUS) was expressed in the leaves of kanamycin-resistant plants that were regnerated, and the presence of the gene was confirmed by Southern analysis. GUS was also observed to be expressed in the latex and more importantly in the serum fraction. Transverse sections of the leaf petiole from a transformed plant revealed GUS expression to be especially enhanced in the phloem and laticifers. GUS expression was subsequently detected in every one of 194 plants representing three successive vegetative cycles propagated from the original transformant. Transgenic Hevea could thus facilitate the continual production of foreign proteins expressed in the latex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002990050454
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    Genetic transformation and regeneration of mature tissues of woody fruit plants bypassing the juvenile stage (1998)
    Springer
    Transgenic research 7 (1998), S. 51-59 
    Details
    ISSN: 1573-9368
    Keywords: sweet orange ; Citrus ; woody ; transformation ; Agrobacterium ; mature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Regeneration and transformation systems from mature plant material of woody fruit species have to be achieved as a necessary requirement for the introduction of useful genes into specific cultivars and the rapid evaluation of resulting horticultural traits. We report here, for the first time, a procedure for genetic transformation and regeneration of mature tissues of woody plants that overcomes the long juvenile periods and high heterozygosity that are characteristic of most of these species. An improved regeneration frequency from mature explants was obtained by invigoration of the plant material through grafting of mature buds on juvenile seedlings. Co-cultivation of the explants in feederplates after inoculation with Agrobacterium tumefaciens resulted in enhanced transformation frequencies. Furthermore, in vitro shoot-tip grafting of the regenerated mature shoots on seedling rootstocks provided a rapid and efficient system for plant production. Citrus is the most extensivel y grown fruit crop worldwide and sweet orange (Citrus sinensis L. Osbeck) accounts for approximately 70% of the Citrus total production. Mature transgenic sweet orange plants have been obtained, which flowered and bore fruit in 14 months
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008855922283
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  • 21
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    An efficient protocol for sugarcane (Saccharum spp. L.) transformation mediated by Agrobacterium tumefaciens (1998)
    Springer
    Transgenic research 7 (1998), S. 213-222 
    Details
    ISSN: 1573-9368
    Keywords: Saccharum ; Agrobacterium ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This is the first successful report of the recovery of morphologically normal transgenic sugarcane plants from co-cultivation of calluses with Agrobacterium tumefaciens. Transformation frequencies (total of transgenic plants/number of cell clusters) were between 9.4 × 10−3 and 1.15 × 10−2. In our experiments, both LBA4404 (pTOK233) and EHA101 (pMTCA3IG), carrying a super-binary vector or supervirulent strain, respectively, were successful for sugarcane transformation. We found that three main factors: (1) the use of young regenerable calluses as target explants; (2) induction and/or improvement of the A. tumefaciens virulence system with sugarcane cell cultures and (3) pre-induction of organogenesis or somatic-embryogenesis-like sexual embryos, seem to be crucial in order to increase the cells competence for T-DNA transfer process. Patterns generated by Southern hybridization confirmed that T-DNAs were randomly integrated into sugarcane genome without th e persistence of A. tumefaciens in the transgenic plants
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008845114531
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  • 22
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    Expression of a chitinase transgene in rose (Rosa hybrida L.) reduces development of blackspot disease (Diplocarpon rosae Wolf) (1998)
    Springer
    Molecular breeding 4 (1998), S. 187-194 
    Details
    ISSN: 1572-9788
    Keywords: chitinase ; Diplocarpon rosae ; disease resistance ; genetic engineering ; Rosa hybrida L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Blackspot, caused by the Ascomycete fungus Diplocarpon rosae, is the most widespread and pernicious disease of cultivated roses. While some species of rose possess resistance to D. rosae, none of the modern-day rose cultivars are fully resistant to the pathogen. In the current study, Biolistic gene delivery was used to introduce a rice gene, encoding a basic (Class I), chitinase into embryogenic callus of the blackspot-susceptible rose (Rosa hybrida L.) cv. Glad Tidings. The plasmid used for transformation carried the neomycin phosphotransferase (nptII) gene facilitating the selection and regeneration of transgenic plants on medium containing 250 mg/l kanamycin. Southern analysis confirmed integration of 2–6 copies of the chitinase gene into the rose genome; gene expression was confirmed by enzyme assay. Bioassays demonstrated that expression of the chitinase transgene reduced the severity of blackspot development by 13–43%. This degree of resistance to the pathogen correlated with the level of chitinase expression in the transgenic rose plants. The introduction of disease defence genes into rose provides a method of producing blackspot-resistant rose cultivars sought by breeders and growers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009642707505
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    Agrobacterium tumefaciens-mediated transformation of cauliflower, Brassica oleracea var. botrytis (1998)
    Springer
    Molecular breeding 4 (1998), S. 531-541 
    Details
    ISSN: 1572-9788
    Keywords: Agrobacterium ; Brassica oleracea ; cauliflower ; regeneration ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We have developed an efficient and simpler method for genetic transformation and regeneration of cauliflower, Brassica oleracea var. botrytis plants. Explants from 4-day old seedlings were inoculated and cocultivated with Agrobacterium tumefaciens strain LBA4404 harbouring a binary vector with the neomycin phosphotransferase-II gene under the regulatory control of nopaline synthase promoter and terminator sequences, permitting transformed shoots to be selected on kanamycin containing medium. After three months rooted transformed plantlets were successfully transferred and grown under glasshouse conditions. Higher numbers of transformed plants were obtained from cotyledon than hypocotyl explants, presumably indicating cotyledons of cauliflower are more amenable to genetic transformation. Integration and expression of the introduced transgene were analysed by DNA gel blot and PCR analysis and NPT-II expression assay. Factors influencing transformation efficiency include explant age, concentration of bacterium used for infection, duration of infection and cocultivation with Agrobacterium. Transgenic plants of three commercial genotypes of cauliflower were produced using this method. We also show that introduction of antisense Bcp1 (pollen-specific gene) linked to a pollen-specific promoter (Lat52) resulted in the expected sterility of 50% pollen carrying this transgenic construct.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009658614579
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  • 24
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    Investigation of Agrobacterium-mediated transformation of apple using green fluorescent protein: high transient expression and low stable transformation suggest that factors other than T-DNA transfer are rate-limiting (1998)
    Springer
    Plant molecular biology 37 (1998), S. 549-559 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium ; apple ; GFP ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To investigate early events of Agrobacterium-mediated transformation of apple cultivars, a synthetic green fluorescent protein gene (SGFP) was used as a highly sensitive, vital reporter gene. Leaf explants from four apple cultivars (‘Delicious’, ‘Golden Delicious’, ‘Royal Gala’ and ‘Greensleeves’) were infected with Agrobacterium EHA101 harboring plasmid pDM96.0501. Fluorescence microscopy indicated that SGFP expression was first detected 48 h after infection and quantitative analysis revealed a high T-DNA transfer rate. Plant cells with stably incorporated T-DNA exhibited cell division and developed transgenic calli, followed by formation of transgenic shoots at low frequencies. The detection of SGFP expression with an epifluorescence stereomicroscope confirmed the effectiveness of SGFP as a reporter gene for detection of very early transformation events and for screening of putative transformants. The efficiency of the transformation and regeneration process decreased ca. 10000-fold from Agrobacterium infection to transgenic shoot regeneration, suggesting that factors other than Agrobacterium interaction and T-DNA transfer are rate-limiting steps in Agrobacterium-mediated transformation of apple.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006041313209
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  • 25
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    The use of visual marker genes as cell-specific reporters of Agrobacterium-mediated T-DNA delivery to wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.). (1998)
    Springer
    Euphytica 99 (1998), S. 17-25 
    Details
    ISSN: 1573-5060
    Keywords: Agrobacterium ; barley ; C1/Lc ; GFP ; GUS ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Transfer of T-DNA from Agrobacterium tumefaciens and A. rhizogenes to cells of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) is demonstrated following the inoculation of immature embryos and immature embryo-derived callus. Agrobacterium T-DNA vectors containing the C1/Lc anthocyanin-biosynthesis regulatory genes, the gusA gene or a synthetic green fluorescent protein gene (sgfp-S65T) were constructed from original binary vectors. The visual T-DNA markers were used as cell-autonomous reporters of early Agrobacterium-mediated transformation events in the wheat and barley cells. This localization of the transformed cells revealed a non-random distribution throughout each embryo and callus piece.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018303102488
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    Metabolic engineering of rice leading to biosynthesis of glycinebetaine and tolerance to salt and cold (1998)
    Springer
    Plant molecular biology 38 (1998), S. 1011-1019 
    Details
    ISSN: 1573-5028
    Keywords: choline oxidase ; genetic engineering ; glycinebetaine ; low-temperature tolerance ; salt tolerance ; transgenic rice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Genetically engineered rice (Oryza sativa L.) with the ability to synthesize glycinebetaine was established by introducing the codA gene for choline oxidase from the soil bacterium Arthrobacter globiformis. Levels of glycinebetaine were as high as 1 and 5 μmol per gram fresh weight of leaves in two types of transgenic plant in which choline oxidase was targeted to the chloroplasts (ChlCOD plants) and to the cytosol (CytCOD plants), respectively. Although treatment with 0.15 m NaCl inhibited the growth of both wild-type and transgenic plants, the transgenic plants began to grow again at the normal rate after a significantly less time than the wild-type plants after elimination of the salt stress. Inactivation of photosynthesis, used as a measure of cellular damage, indicated that ChlCOD plants were more tolerant than CytCOD plants to photoinhibition under salt stress and low-temperature stress. These results indicated that the subcellular compartmentalization of the biosynthesis of glycinebetaine was a critical element in the efficient enhancement of tolerance to stress in the engineered plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006095015717
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  • 27
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    Cre/lox-mediated site-specific integration of Agrobacterium T-DNA in Arabidopsis thaliana by transient expression of cre (1998)
    Springer
    Plant molecular biology 38 (1998), S. 393-406 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium ; Arabidopsis ; Cre/lox ; recombination ; site-specific integration ; T-DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Cre/lox system was used to obtain targeted integration of an Agrobacterium T-DNA at a lox site in the genome of Arabidopsis thaliana. Site-specific recombinants, and not random events, were preferentially selected by activation of a silent lox-neomycin phosphotransferase (nptII) target gene. To analyse the effectiveness of Agrobacterium-mediated transfer we used T-DNA vectors harbouring a single lox sequence (this vector had to circularize at the T-DNA left- and right-border sequences prior to site-specific integration) or two lox sequences (this vector allowed circularization at the lox sequences within the T-DNA either prior to or after random integration, followed by targeting of the circularized vector), respectively. Furthermore, to control the reversibility of the integration reaction, Cre recombinase was provided transiently by using a cotransformation approach. One precise stable integrant was found amongst the recombinant calli obtained after transformation with a double-lox T-DNA vector. The results indicate that Agrobacterium-mediated transformation can be used as a tool to obtain site-specific integration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006024500008
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    How will bioinformatics influence metabolic engineering? (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 58 (1998), S. 162-169 
    Details
    ISSN: 0006-3592
    Keywords: bioinformatics ; metabolic engineering ; genetic engineering ; mathematical analysis ; stoichiometry ; enzyme kinetics ; modal analysis ; genetic circuits ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Ten microbial genomes have been fully sequenced to date, and the sequencing of many more genomes is expected to be completed before the end of the century. The assignment of function to open reading frames (ORFs) is progressing, and for some genomes over 70% of functional assignments have been made. The majority of the assigned ORFs relate to metabolic functions. Thus, the complete genetic and biochemical functions of a number of microbial cells may be soon available. From a metabolic engineering standpoint, these developments open a new realm of possibilities. Metabolic analysis and engineering strategies can now be built on a sound genomic basis. An important question that now arises; how should these tasks be approached? Flux-balance analysis (FBA) has the potential to play an important role. It is based on the fundamental principle of mass conservation. It requires only the stoichiometric matrix, the metabolic demands, and some strain specific parameters. Importantly, no enzymatic kinetic data is required. In this article, we show how the genomically defined microbial metabolic genotypes can be analyzed by FBA. Fundamental concepts of metabolic genotype, metabolic phenotype, metabolic redundancy and robustness are defined and examples of their use given. We discuss the advantage of this approach, and how FBA is expected to find uses in the near future. FBA is likely to become an important analysis tool for genomically based approaches to metabolic engineering, strain design, and development. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 58:162-169, 1998.
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    Electronic Resource
    Crystal structures and properties of de novo circularly permuted 1,3-1,4-β-glucanases (1998)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 30 (1998), S. 155-167 
    Details
    ISSN: 0887-3585
    Keywords: X-ray diffraction ; protein folding ; genetic engineering ; circular permutation ; 1,3-1,4-β-glucanase ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The 1,3-1,4-β-glucanases from Bacillus macerans and Bacillus licheniformis, as well as related hybrid enzymes, are stable proteins comprised of one compact jellyroll domain. Their structures are studied in an effort to reveal the degree of redundancy to which the three-dimensional structure of protein domains is encoded by the amino acid sequence. For the hybrid 1,3-1,4-β-glucanase H(A16-M), it could be shown recently that a circular permutation of the sequence giving rise to the variant cpA16M-59 is compatible with wildtype-like enzymatic activity and tertiary structure (Hahn et al., Proc. Natl. Acad. Sci. USA 91:10417-10421, 1994). Since the circular permutation yielding cpA16M-59 mimicks that found in the homologous enzyme from Fibrobacter succinogenes, the question arose whether de novo circular permutations, not guided by molecular evolution of the 1,3-1,4-β-glucanases, could also produce proteins with native-like fold. The circularly permuted variants cpA16M-84, cpA16M-127, and cpA16M-154 were generated by PCR mutagenesis of the gene encoding H(A16-M), synthesized in Escherichia coli and shown to be active in β-glucan hydrolysis. CpA16M-84 and cpA16M-127 were crystallized in space groups P21 and P1, respectively, and their crystal structures were determined at 1.80 and 2.07 Å resolution. In both proteins the main parts of the β-sheet structure remain unaffected by the circular permutation as is evident from a root-mean-square deviation of main chain atoms from the reference structure within the experimental error. The only major structural perturbation occurs near the novel chain termini in a surface loop of cpA16M-84, which becomes destabilized and rearranged. The results of this study are interpreted to show that: (1) several circular permutations in the compact jellyroll domain of the 1,3-1,4-β-glucanases are tolerated without radical change of enzymatic activity or tertiary structure, (2) the three-dimensional structures of simple domains are encoded by the amino acid sequence with sufficient redundancy to tolerate a change in the sequential order of secondary structure elements along the sequence, and (3) the native N-terminal region is not needed to guide the folding polypeptide chain toward its native conformation. Proteins 30:155-167, 1998. © 1998 Wiley-Liss, Inc.
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    Genetic Engineering of Protein-Based Polymers: Potential in Controlled Drug Delivery (1998)
    Springer
    Pharmaceutical research 15 (1998), S. 813-815 
    Details
    ISSN: 1573-904X
    Keywords: genetic engineering ; polymers ; drug delivery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1011999810298
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    Review: Application of biotechnology to forestry – molecular biology of conifers (1998)
    Springer
    World journal of microbiology and biotechnology 14 (1998), S. 321-330 
    Details
    ISSN: 1573-0972
    Keywords: Conifer transformation ; forestry ; genetic engineering ; plantation forestry ; tree improvement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Genetic improvement in plantation forestry relies significantly on conventional breeding techniques which have been used extensively to improve various characteristics in forest trees such as growth and form, volume yield, resistance to pathogens and quality of the end product. This review concentrates on molecular techniques which have been used successfully in agriculture and which have more recently become available to improve further characteristics of forest trees and introduce new traits which are currently not available in the breeding population.
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    URL: http://dx.doi.org/10.1023/A:1008848824626
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  • 32
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    Stable Production of Human Insulin-like Growth Factor 1 (IGF-1) in the Milk of Hemi- and Homozygous Transgenic Rabbits Over Several Generations (1998)
    Springer
    Transgenic research 7 (1998), S. 437-447 
    Details
    ISSN: 1573-9368
    Keywords: bioreactor ; gene farming ; genetic engineering ; mammary gland ; milk composition ; recombinant protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract One transgenic rabbit line was generated carrying a fusion gene consisting of the cDNA for human IGF-1 fused to a mammary gland specific expression cassette derived from bovine alpha-S1-casein sequences. Transgene expression was shown to be strictly tissue and lactation period specific. The transgenic rabbit line was bred for six generations. All transgenic animals showed stable production of biologically active IGF-1 over the generations and no apparent effect on the physiological or reproductive performance was observed. The absence of adverse effects on homozygous transgenic rabbits suggested the absence of insertional mutagenesis. Eight hemizygous transgenic offspring analysed produced on average 363 ± 12μg/ml (ranging from 223 ± 61 to 484 ± 39 μg/ml) mature human IGF-1 in their milk, whereas three homozygous animals produced on average 543 ± 41 μg/ml (ranging from 360 ± 15 to 678 ± 80 μg/ml). Homozygous huIGF-1 females clearly showed a significantly increased production performance of the recombinant protein.
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    URL: http://dx.doi.org/10.1023/A:1008831028620
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    Genetically engineered syntheses of tandem repetitive polypeptides consisting of glycine-rich sequence of spider dragline silk (1998)
    New York : Wiley-Blackwell
    Biopolymers 45 (1998), S. 269-279 
    Details
    ISSN: 0006-3525
    Keywords: spider dragline silk ; genetic engineering ; glycine-rich sequence ; β-sheet structure ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We described genetically engineered syntheses of tandem repetitive polypeptides consisting of glycine-rich sequence, GlyLeuGlyGlyGlnGlyGlyGlyAlaGlyGlnGlyGlyTyrGly, designated SCAP(1), in spidroin I of spider dragline silk from Nephila clavipes and the secondary conformational analyses in the solid state by Fourier transform ir measurements. The polypeptides composed of 4, 5, 6, 7, 11, 12, or 13 repeats of SCAP(1) were expressed in Escherichia coli, purified by nickel chelate affinity chromatography, and then cleaved with cyanogen bromide to release N- and C-terminal extensions. Typical yields were from 1.2 to 5.2 mg of lyophilized uncleaved polypeptides per liter of fermentation medium at an absorbance of 2.0 at 600 nm, and the production levels increased with decreasing the molecular weight of the expressed polypeptides. The lyophilized powder of cleaved SCAP(13) adopted the random coil, whereas the cast film from formic acid formed the β-sheet structure. The conformational results might indicate that the glycine-rich sequence formed β-sheet structure in spidroin I. Cleaved SCAP(13) started to decompose under nitrogen at ca. 230°C, which was in agreement with the decomposition temperature of the spider dragline silk from N. clavipes. © 1998 John Wiley & Sons, Inc. Biopoly 45: 269-279, 1998
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    Genetic engineering of Serratia marcescens with bacterial hemoglobin gene: Effects on growth, oxygen utilization, and cell size (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 57 (1998), S. 477-483 
    Details
    ISSN: 0006-3592
    Keywords: Vitreoscilla hemoglobin ; bacterial hemoglobin ; Serratia marcescens ; genetic engineering ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The bacterial hemoglobin from Vitreoscilla has been shown to increase growth yield and yield of genetically engineered product in Escherichia coli. To test the generality of this phenomenon, the approximately 560-bp bacterial (Vitreoscilla) hemoglobin gene (vgb) (including the native promoter), cloned into the vector pUC8 in two constructs containing about 1650 and 850 bp, respectively, of Vitreoscilla DNA downstream of vgb, was transformed into Serratia marcescens. After several transfers of the transformants on selective media, both plasmids became stable in this host and the resulting strains produced hemoglobin. Both transformants were compared, regarding growth in liquid Luria-Bertani (LB) medium, with untransformed S. marcescens and S. marcescens transformed with pUC8. The vgb-bearing strains had about 5 times lower maximum viable cell numbers than the strains without hemoglobin, but the former also had late log or early stationary phase cells that were 5-10 times larger than those of the latter. Further, on a dry cell mass basis the presence of vgb inhibited cell growth in liquid media. In contrast, growth of the vgb-bearing strains on LB plates based on cell mass (determined from colony size) was markedly enhanced compared with that of the pUC8 transformant. Respiration of the vgb-bearing strains was lower than that of the strains without vgb on a cell mass basis. These results show that the presence of vgb can have idiosyncratic effects and is not always an aid to cell growth so that its use for genetic engineering must be tested on a case by case basis. ©1998 John Wiley & Sons, Inc. Biotechnol Bioeng 57: 477-483, 1998.
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    Genetic engineering approaches to enzyme design and mechanism (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 536-539 
    Details
    ISSN: 0894-3230
    Keywords: enzyme design ; enzyme mechanism ; genetic engineering ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Aspartate aminotransferase (AATase) and aminocyclopropane carboxylate synthase (ACC synthase) are pyridoxal phosphate (PLP)-dependent enzymes whose common junction of mechanistic divergence is after the formation of a Cα carbanion from the amino acid substrate bound to PLP as a Schiff base (aldimine). AATase catalyzes the reversible interconversion of α-amino acids and α-keto acids, while ACC synthase effects the irreversible decomposition of S-adenosylmethionine (SAM) to 1-aminocyclopropane-1-carboxylate (ACC) and 5′-methylthioadenosine (MTA). ACC is subsequently converted to ethylene, the plant ripening and senescence hormone, by ACC oxidase, the next enzyme in the pathway. AATase and ACC synthase exhibit many similar phenomenological characteristics that result from different detailed mechanistic origins. The kcat/KM versus pH profiles for both enzymes are similar (AATase, acidic pKa = 6.9, basic pKa = 9.6; ACC synthase, acidic pKa = 7.5, basic pKa = 8.9); however the acidic pKa of AATase reflects the ionization of an enzyme proton from the internal Schiff base, and the basic one is that of the α-amino group of the substrate, while the opposite situation obtains for ACC synthase, i.e. the apparent pKa of 7.4 is due to the α-amino group of SAM, whereas that of 9 reflects the Schiff base pKa. The mechanistic imperative underlying this reversal is dictated by the reaction mechanism and the low pKa of the α-amino group of SAM. The low pKa of SAM requires that the enzyme pKa be moved upward in order to have sufficient quantities of the reacting species at neutral pH. It is shown by viscosity variation experiments with wild-type and active site mutant controls of both enzymes that the reaction of SAM with ACC synthase is 100% diffusion controlled (kcat/KM = 1.2 × 106 l mol-1 s-1) while the corresponding reaction for the combination of L-aspartate with AATase is insensitive to viscosity, and is therefore chemically not diffusion limited. Tyr225 (AATase) or Tyr233 (ACC synthase) forms a hydrogen bond with the PLP in both enzymes, but that formed with the former enzyme is stronger and accounts for the lower pKa of the Schiff base. © 1998 John Wiley & Sons, Ltd.
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    Is there any possibility of detecting the use of genetic engineering in processed foods? (1997)
    Springer
    European journal of nutrition 36 (1997), S. 155-160 
    Details
    ISSN: 1436-6215
    Keywords: Detection method ; genetic engineering ; polymerase chain reaction ; processed food ; Gentechnik ; Nachweisverfahren ; Polymerasekettenreaktion ; verarbeitete Lebensmittel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Bier, Sojaöl, verarbeitete Tomaten- (Ketchup, Mark, Pizzatomaten, Schältomaten, Suppe) und Kartoffelprodukte (Pommes frites, Chips, Püree, Mehl, Stärke, Bratkartoffeln) sowie ein Enzympräparat (Natuphos) wurden mittels PCR daraufhin untersucht, ob ein Nachweis des Einsatzes der Gentechnik bei ihrer Herstellung möglich ist. PCR-fähige DNA ließ sich aus Pizzatomaten, Schältomaten, Pommes frites, Bratkartoffeln, Kartoffelmehl und Kartoffelchips isolieren, so daß der Nachweis des Einsatzes der Gentechnik bei deren Herstellung möglich wird. Bestimmte Biere (Pils, Export, Nutfield lyte), Sojaöl, Tomatensuppe, Kartoffelstärke, Kartoffelpüree und Natuphos entziehen sich einem solchen Nachweis, da die PCR-Analyse keine Hinweise auf das Vorliegen von DNA in diesen Produkten ergab. Daß das durchgeführte Nachweisverfahren grundsätzlich in der Lage ist, geringe Mengen an DNA auch in diesen Produkten spezifisch nachzuweisen, wurde nach Zugabe vonEscherichia coli DNA bestätigt.
    Notes: Summary To elucidate if there is any possibility to identify highly processed foods as produced through genetic engineering, beer, soya bean oil, processed tomato (ketch-up, paste, pizza tomatoes, peeled tomatoes, soup) and potato (french fries, crisps, mashed potatoes, flour, starch, fried potatoes) products as well as an enzyme preparation (Natuphos) were investigated by PCR. In pizza tomatoes, peeled tomatoes, french fries, fried potatoes, potato flour and potato crisps DNA suitable for PCR was found. Therefore, it is possible to identify these products as produced through genetic engineering. Such an identification is impossible in certain beers (pilsener, export, Nutfield lyte), soya bean oil, tomato soup, potato starch, mashed potatoes and Natuphos since PCR-analysis gave no indication of the presence of DNA in these products. As it was shown by addingEscherichia coli DNA the used method is, in principle, capable of detecting specifically small amounts of DNA in such products.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01611394
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  • 37
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    Electronic Resource
    Transgenic Populus tremula: a step-by-step protocol for its Agrobacterium-mediated transformation (1997)
    Springer
    Plant molecular biology reporter 15 (1997), S. 219-235 
    Details
    ISSN: 1572-9818
    Keywords: Agrobacterium ; Populus ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In recent years, Populus species have acquired an important place in basic and applied research of woody plants. The practical role of Populus species in world forestry and their importance to research as a woody-plant model have led to increasing interest in tissue-culture and molecular techniques, as well as the development of transformation procedures for this genus. A simple technical procedure is described here step-by-step, for the first time, as a routine method for transforming Populus tremula using a disarmed Agrobacterium tumefaciens hypervirulent strain. The procedure begins with the inoculation of stem explants with bacterial suspension, followed by a short period of co-cultivation on a highly regenerative medium. Transformed shoots are selected on regeneration medium containing antibiotics and the presence of the inserted target genes is checked using a rapid and efficient PCR test. Selected shoots are transferred to a rooting medium, under the same selection pressure, and propagated via stem cuttings. Selected plants can be hardened and transferred to the green-house within 4 months of inoculation. The method has proven efficient for several gene constructs, selection on Kan or Hyg, and three different Agrobacterium strains.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007484917759
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  • 38
    Electronic Resource
    Electronic Resource
    Genetic engineering of bacteria and their potential for Hg2+ bioremediation (1997)
    Springer
    Biodegradation 8 (1997), S. 97-103 
    Details
    ISSN: 1572-9729
    Keywords: Escherichia coli ; genetic engineering ; mercury bioaccumulation ; mercury transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Ion exchange or biosorptive processes for metalremoval generally lack specificity in metal bindingand are sensitive to ambient conditions, e.g. pH,ionic strength and the presence of metal chelators. Inthis study, cells of a genetically engineered Escherichia coli strain, JM109, which expressesmetallothionein and a Hg2+ transport system afterinduction were evaluated for their selectivity forHg2+ accumulation in the presence of sodium,magnesium, or cadmium ions and their sensitivity to pHor the presence of metal chelators during Hg2+bioaccumulation. The genetically engineered E.coli cells in suspension accumulated Hg2+effectively at low concentrations (0-20 µM) overa broad range of pH (3 to 11). The presence of 400 mMsodium chloride, 200 mM magnesium chloride, or100 µM cadmium ions did not have a significanteffect on the bioaccumulation of 5 µm Hg2+,indicating that this process is not sensitive to highionic strength and is highly selective against sodium,magnesium, or cadmium ions. Metal chelators usuallyinterfere with ion exchange or biosorptive processes.However, two common metal chelators, EDTA and citrate,had no significant effect on Hg2+ bioaccumulationby the genetically engineered strain. These resultssuggest that this E. coli strain could be usedfor selective removal of Hg2+ from waste water orfrom contaminated solutions which are resistant tocommon treatments. A second potential applicationwould be to remove Hg2+ from Hg2+-contaminated soil, sediment, or particulates bywashing them with a Hg2+ chelator andregenerating the chelator by passing the solutionthrough a reactor containing the strain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008233704719
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  • 39
    Electronic Resource
    Electronic Resource
    Engineered cell lines for insulin replacement in diabetes: current status and future prospects (1997)
    Springer
    Diabetologia 40 (1997), S. S42 
    Details
    ISSN: 1432-0428
    Keywords: Keywords Insulin ; genetic engineering ; cell lines ; transplantation ; molecular biology.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The recently completed diabetes complications and control trial has highlighted the need for improvement of insulin delivery systems for treatment of insulin-dependent diabetes mellitus. Despite steady improvement in methods for islet and whole pancreas transplantation over the past three decades, the broad-scale applicability of these approaches remains uncertain due in part to the difficulty and expense associated with procurement of functional tissue. To address this concern, we and others have been using the tools of molecular biology to develop cell lines with regulated insulin secretion that might serve as a surrogate for primary islets or pancreas tissue in transplantation therapy. This article seeks to provide a brief summary of the current status of this growing field, with a particular emphasis on progress in producing cell lines with appropriate glucose-stimulated insulin secretion. [Diabetologia (1997) 40: S 42–S 47]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001250051398
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  • 40
    Electronic Resource
    Electronic Resource
    Role of the host cell cycle in theAgrobacterium-mediated genetic transformation ofPetunia: Evidence of an S-phase control mechanism for T-DNA transfer (1997)
    Springer
    Planta 201 (1997), S. 160-172 
    Details
    ISSN: 1432-2048
    Keywords: Agrobacterium ; Leaf mesophyll cells ; Petunia ; Transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chimeric β-glucuronidase (GUS) gene expression in an efficientAgrobacterium-mediated transformation system utilising mesophyll cells ofPetunia hybrida synchronized with cell cycle phase-specific inhibitors (mimosine and colchicine) was used to show the absolute requirement of S-phase for transfer and/or integration of the transferred DNA (T-DNA). Flow-cytometric analysis of nuclear DNA content and immunohistological detection of bromodeoxyuridine (BrdUrd) incorporation showed that, prior to phytohormone treatment, most (98%) mesophyll cells were at GO-Gl-phase (quiescent phase) and no cell division was occurring. After 48 h and 72 h of phytohormone treatment, there was a rapid increase in S-G2-M-phase populations (〉 75%) and a concomitant decrease (down to 24%) in G0–-G1-phase cells. Assays of GUS showed that maximum transformation (〉 95% of explants) also occurred after this period. Our data showed that mimosine and colchicine blocked the mesophyll cells at late Gl-phase and M-phase, respectively. No transformation (= GUS expression) was observed in phytohormone-treated cells inhibited in late G1 by mimosine. However, after removal of mimosine, 82% of the explants were transformed, indicating the non-toxic and reversible effect of the inhibitor. On the other hand, a relatively high transformation frequency (65% of explants) was observed after blocking the cell cycle at M-phase with colchicine. However, only transient, but no stable, gene expression (= kanamycin-resistant callus formation) was observed in colchicine-treated M-phase-arrested cells. Similarly, endoreduplication of nuclear DNA, which occurred during the 48 h of phytohormone treatment in some mesophyll cells and cells located along the minor veins in the leaf explants, resulted in transient GUS expression only. These observations indicate a direct correlation between endoreduplication and transient GUS gene expression. Obviously, for stable GUS gene expression, cell division and proliferation are required, indicating that both DNA duplication (S-phase) and cell division (M-phase) are strongly related to stable transformation. We propose that the present system should facilitate further dissection of the process of T-DNA integration in the host genome and therefore should aid in developing new strategies for transformation of recalcitrant plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01007700
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  • 41
    Electronic Resource
    Electronic Resource
    Expression and inheritance of foreign genes in transgenic peanut plants generated byAgrobacterium-mediated transformation (1997)
    Springer
    Plant cell reports 16 (1997), S. 541-544 
    Details
    ISSN: 1432-203X
    Keywords: Transgenic peanut ; Agrobacterium ; Transformation ; Transgene expression ; Transgene inheritance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To evaluate and characterize the stability of traits transferred viaAgrobacterium transformation, foreign gene expression must be examined in sexually derived progeny. The objective of this study was to analyze three transgenic peanut plants, 1-10, 12-1, and 17-1, for the inheritance and expression of their foreign genes. Segregation ratios for the introduced genes in T2 plants gave either 100% or 3:1 expression of the β-glucuronidase (GUS) gene, demonstrating recovery of both homozygous and heterozygous T1 plants. Fluorometric GUS assay in T1 and T2 generations of all three plants showed that the GUS gene was stably expressed in the progeny. DNA analyses showed 100% concordance between the presence of the foreign gene and enzyme activity. Our results demonstrate that transgenes in peanut introduced byAgrobacterium can be inherited in a Mendelian manner.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01142320
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  • 42
    Electronic Resource
    Electronic Resource
    Isolation of new 6-methylnicotinic-acid-degrading bacteria, one of which catalyses the regioselective hydroxylation of nicotinic acid at position C2 (1997)
    Springer
    Archives of microbiology 168 (1997), S. 355-361 
    Details
    ISSN: 1432-072X
    Keywords: Key words 6-Methylnicotinic acid ; 2-Hydroxy-6-methylnicotinic acid ; Nicotinic acid ; 2-Hydroxynicotinic acid ; Ralstonia ; Burkholderia ; Paenibacillus ; Agrobacterium ; Rhizobium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 2-Hydroxynicotinic acid is an important building block for herbicides and pharmaceuticals. Enrichment strategies to increase the chances of finding microorganisms capable of hydroxylating at the C2 position and to avoid the degradation of nicotinic acid via the usual intermediate, 6-hydroxynicotinic acid, were used. Three bacterial strains (Mena 23/3–3c, Mena 25/4–1, and Mena 25/ 4–3) were isolated from enrichment cultures with 6-methylnicotinic acid as the sole source of carbon and energy. Partial characterization of these strains indicated that they represent new bacterial species. All three strains completely degraded 6-methylnicotinic acid, and evidence is presented that the first step in the degradation pathway of strain Mena 23/3–3c is hydroxylation at the C2 position. Resting cells of this strain grown on 6-methylnicotinic acid also hydroxylated nicotinic acid at the C2 position, but did not further degrade the product. Strain Mena 23/ 3–3c showed the highest degree of 16S rRNA sequence similarity to members of the genera Ralstonia and Burkholderia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002030050509
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  • 43
    Electronic Resource
    Electronic Resource
    Excision of the maize transposable element Ac in periclinal chimeric leaves of 35S-Ac-rolC transgenic aspen-Populus (1997)
    Springer
    Plant molecular biology 33 (1997), S. 1097-1103 
    Details
    ISSN: 1573-5028
    Keywords: Ac ; Agrobacterium ; periclinal chimera ; rolC ; transgenic Populus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The transposable element Ac from maize, in combination with the phenotypic selectable marker rolC, was employed in transformation experiments of a hybrid aspen clone. A number of transgenic clones exhibited light-green sectors on green leaves. In vitro regeneration from leaves showing a high number of light-green spots resulted in R2 plants, which also showed light-green sectored leaves. However, only one out of 385 regenerated plants obtained showed green leaves. Both PCR and northern analysis indicated Ac excision and restoration of rolC expression. In Southern blot analysis of this green plant additional bands were observed as compared to the original R1 plant. The occurrence of these bands and a suggested Ac excision in the non-green L1-epidermal layer leading to periclinal chimerism of this plant is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005788706864
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  • 44
    Electronic Resource
    Electronic Resource
    Tapetum-specific expression of theOsg6B promoter-β-glucuronidase gene in transgenic rice (1997)
    Springer
    Plant cell reports 16 (1997), S. 363-367 
    Details
    ISSN: 1432-203X
    Keywords: Agrobacterium ; Tapetum-specific promoter ; Transformation ; Rice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The promoter of an anther tapetum-specific gene,Osg6B, was fused to aβ-glucuronidase (GUS) gene and introduced into rice byAgrobacterium-mediated gene transfer. Fluorometric and histochemical GUS assay showed that GUS was expressed exclusively within the tapetum of anthers from the uninucleate microspore stage (7 days before anthesis) to the tricellular pollen stage (3 days before anthesis). This is the first demonstration of an anther-specific promoter directing tapetum-specific expression in rice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01146774
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  • 45
    Electronic Resource
    Electronic Resource
    Expression and inheritance of foreign genes in transgenic peanut plants generated by Agrobacterium-mediated transformation (1997)
    Springer
    Plant cell reports 16 (1997), S. 541-544 
    Details
    ISSN: 1432-203X
    Keywords: Key words Transgenic peanut ; Agrobacterium ; Transformation ; Transgene expression ; Transgene inheritance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To evaluate and characterize the stability of traits transferred via Agrobacterium transformation, foreign gene expression must be examined in sexually derived progeny. The objective of this study was to analyze three transgenic peanut plants, 1-10, 12-1, and 17-1, for the inheritance and expression of their foreign genes. Segregation ratios for the introduced genes in T2 plants gave either 100% or 3:1 expression of the β-glucuronidase (GUS) gene, demonstrating recovery of both homozygous and heterozygous T1 plants. Fluorometric GUS assay in T1 and T2 generations of all three plants showed that the GUS gene was stably expressed in the progeny. DNA analyses showed 100% concordance between the presence of the foreign gene and enzyme activity. Our results demonstrate that transgenes in peanut introduced by Agrobacterium can be inherited in a Mendelian manner.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01142320
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  • 46
    Electronic Resource
    Electronic Resource
    Genetic transformation of Populus genotypes with different chimaeric gene constructs: transformation efficiency and molecular analysis (1997)
    Springer
    Transgenic research 6 (1997), S. 111-121 
    Details
    ISSN: 1573-9368
    Keywords: Ac ; Agrobacterium ; aspen ; Populus ; transformation ; transposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Aspen (Populus tremula) and hybrid aspen (P. tremula × P. tremuloides) were transformed with different gene constructs using two types of promoter. The aim was to determine the influence of the reporter gene rolC, controlled by promoters of viral or plant origin, on genetic and morphologic expression of different transgenic aspen clones. An improved transformation method using leaf discs was developed, by which putative transgenic plantlets were regenerated at high efficiencies (up to 34%) on kanamycin-containing medium. Transgenic aspen carrying the rolC gene from Agrobacterium rhizogenes under control of the cauliflower-35S-promoter are reduced in size with smaller leaves, whereas aspen transgenic for the same rolC gene, but under control of the light inducible rbcS promoter from potato, are only slightly reduced in size compared to untransformed controls. However, all clones carrying 35S-rolC and rbcS-rolC genes revealed light-green colouration of leaves when compared to untransformed aspen. Owing to this special feature, constructs were used in which expression of the rolC gene was inhibited by insertion of a transposable element, Ac, from maize. Transgenic aspen transformed with the 35S-Ac-rolC and rbcS-Ac-rolC genes were morphologically similar to untransformed aspen, but out of 54 independently regenerated 35S-Ac-rolC transgenic aspen clones, 30 clones showed light-green/dark green variegated leaves. In contrast, out of 19 independently transformed rbcS-Ac-rolC aspen clones, only two clones revealed light-green/dark green variegated leaves. The role of bacterial strains in transformation, and molecular genetics of transgenic aspen plants (including the function of the transposable element, Ac, in the aspen genome) are discussed
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018421620040
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  • 47
    Electronic Resource
    Electronic Resource
    Plant nutrition in the 20th and perspectives for the 21st century (1997)
    Springer
    Plant and soil 196 (1997), S. 163-174 
    Details
    ISSN: 1573-5036
    Keywords: fertilizers ; food production ; genetic engineering ; macronutrients ; micronutrients ; nutrient absorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This paper briefly presents the knowledge of plant nutrition in 1900 and its expansion since then in two areas - the discovery of the micronutrients and the absorption of nutrients from soils. Application of macro- and micronutrient fertilizers has contributed substantially to the huge increase in world food production experienced this century. In developed countries, excessive fertilizer use has led to serious problems of nutrient pollution; here, plant nutritionists will be concerned with monitoring nutrient status of crops and soils to maintain crop production with minimum loss of nutrients to the environment, and development of cultivars with high nutrient efficiency in soils with luxury supplies of nutrients. In many developing countries, soil infertility limits productivity; here, plant nutritional research can raise productivity by diagnosis of nutrient deficiencies and toxicities of crops on previously unfertilized soils, their correction with minimal fertilizer and treatment costs, and development of cultivars with high nutrient efficiency in deficient soils and high tolerance of natural toxicities. The pre-occupation of developed countries with pollution is blinding them to the urgent needs of developing countries for fertilizers and fertilizer research to increase crop production ha-1 as an alternative to clearing more land.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004208621263
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  • 48
    Electronic Resource
    Electronic Resource
    Rice transformation: bombardment (1997)
    Springer
    Plant molecular biology 35 (1997), S. 197-203 
    Details
    ISSN: 1573-5028
    Keywords: genetic engineering ; particle bombardment ; plant biotechnology ; transgenic rice ; Oryza sativa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Bombardment-based methodology is responsible for the effective genetic manipulation of major cereals including rice. Many groups reported significant advances on various aspects of rice molecular biology and genetic engineering using procedures based on bombardment technology. Molecular and genetic characterization of large numbers of these plants (more than 500 independent transgenic plants) provided information on structure, expression and stability of integrated DNA through multiple generations. Such evaluations were carried out in the greenhouse and in the field. Stability of expression was found to be dependent on the nature of the promoter and the transgene, and in specific cases on gene copy number. Direct DNA transfer utilizing particle bombardment for the delivery of foreign DNA into rice tissue results in the recovery of large numbers of independently derived transgenic plants in a variety-independent fashion. Gene copy number, level and stability of expression of transgenes can be compared to other DNA delivery methods, direct or indirect, including Agrobacterium-mediated gene transfer. In this paper, the technology is summarized and discussed in terms of present and future applications, including field trials and potential commercialization of transgenic rice expressing a number of genes of agronomic interest such as pest and herbicide resistance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005791230345
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  • 49
    Electronic Resource
    Electronic Resource
    Agrobacterium rhizogenes and A. tumefaciens co-transformation to obtain grapevine hairy roots producing the coat protein of grapevine chrome mosaic nepovirus (1997)
    Springer
    Plant cell, tissue and organ culture 49 (1997), S. 53-62 
    Details
    ISSN: 1573-5044
    Keywords: Agrobacterium ; coat protein ; grapevine ; hairy root ; nepovirus ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Hairy root cultures of grapevine were obtained from plantlets co-inoculated by virulent Agrobacterium rhizogenes strains and disarmed A. tumefaciens strains harbouring the binary vectors pKHG4 and pKVHG 2+. These plasmids contain the nptII, hpt and gus genes and differ for the presence of the gene encoding for the grapevine chrome mosaic virus coat protein. For the cultivar ‘Gravesac’, 72% of the excised root tips initiated hairy root cultures on growth regulator-free media. According to the nature of the strains used in co-inoculation, co-transformation frequencies of the hairy root clones ranged from 4 to 16%. Co-transformed roots showed resistance to kanamycin and hygromycin but responses varied from clone to clone. Fluorometric GUS expression and GCMV coat protein production showed a large variability among hairy root clones co-transformed by pKHVG2+. Though the presence of gus, nptII and GCMV coat protein genes was checked by polymerase chain reaction and Southern blotting, it was difficult to establish a clear relationship between expression of the different transgenes. The regeneration of plants was not achieved, but the possibility to graft in vitro transgenic roots to non transformed shoot systems could permit rapid testing of the resistance induced by nepovirus coat protein in roots of cultivars that are recalcitrant to A. tumefaciens-mediated transformation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005854212592
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  • 50
    Electronic Resource
    Electronic Resource
    Isolation and identification of N2-fixing microorganisms from the rhizosphere of Capparis spinosa (L.) (1997)
    Springer
    Plant and soil 197 (1997), S. 19-23 
    Details
    ISSN: 1573-5036
    Keywords: Agrobacterium ; Capparis spinosa ; Comamonas ; N2 fixation ; Pseudomonas ; rhizosphere ; Sphingobacterium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Four bacterial strains, Pseudomonas stutzeri var. mendocina, Comamonas sp., Agrobacterium tumefaciens biovar. 2 and Sphingobacterium sp., isolated from the rhizosphere of wild-grown caper (Capparis spinosa L.) plants were able to fix N2 as shown by their growth in nitrogen-free medium and by the acetylene reduction test. P. stutzeri var. mendocina and Comamonas sp. contained DNA homologous to the Klebsiella pneumoniae M5a1 nifHDK genes. No hybridization was found with total DNA from either A. tumefaciens biovar. 2 or Sphingobacterium sp. using nifHDK probes from either K. pneumoniae or Rhizobium meliloti.
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    URL: http://dx.doi.org/10.1023/A:1004211909641
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  • 51
    Electronic Resource
    Electronic Resource
    Nif gene transfer and expression in chloroplasts: Prospects and problems (1997)
    Springer
    Plant and soil 194 (1997), S. 193-203 
    Details
    ISSN: 1573-5036
    Keywords: chloroplast ; genetic engineering ; nif genes ; nitrogenase ; plant transformation ; plastid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The engineering of plants capable of fixing their own nitrogen is an extremely complex task, requiring the co-ordinated and regulated expression of 16 nif genes in an appropriate cellular location. We suggest that plastids may provide a favourable environment for nif gene expression provided that the nitrogenase enzyme can be protected from oxygen damage. Using the non-heterocystous cyanobacteria as a model, we argue that photosynthesis could be temporally separated from nitrogen fixation in chloroplasts by restricting nitrogenase synthesis to the dark period. We report preliminary data on the introduction and expression of one of nitrogenase components, the Fe protein, in transgenic tobacco and Chlamydomonas reinhardtii. Finally we discuss potential avenues for further research in this area and the prospects for achieving the ultimate goal of expressing active nitrogenase in cereal crops such as rice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004296703638
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  • 52
    Electronic Resource
    Electronic Resource
    SAAT: sonication-assisted Agrobacterium-mediated transformation (1997)
    Springer
    Transgenic research 6 (1997), S. 329-336 
    Details
    ISSN: 1573-9368
    Keywords: Agrobacterium ; SAAT ; sonication ; transformation ; wounding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Plant transformation via Agrobacterium can be limited by both host specificity and the inability of Agrobacterium to reach the proper cells in the target tissue. Described here is a new and efficient Agrobacterium-based transformation technology that overcomes these barriers and enhances DNA transfer in such diverse plant groups as dicots, monocots, and gymnosperms. This new technology, called sonication-assisted Agrobacterium-mediated transformation (SAAT), involves subjecting the plant tissue to brief periods of ultrasound in the presence of Agrobacterium. Scanning electron and light microscopy reveal that SAAT treatment produces small and uniform fissures and channels throughout the tissue allowing the Agrobacterium easy access to internal plant tissues. Unlike other transformation methods, this system has the potential to transform meristematic tissue buried under several cell layers. SAAT increases transient transformation efficiency in several different plant tissues including leaf tissue, immature cotyledons, somatic and zygotic embryos, roots, stems, shoot apices, embryogenic suspension cells and whole seedlings. A 100- to 1400-fold increase in transient β- glucuronid ase expression has been demonstrated in various tissues of soybean, Ohio buckeye, cowpea, white spruce, wheat and maize. Stable transformation of both soybean and Ohio buckeye has been obtained using SAAT of embryogenic suspension culture tissues. For soybean, SAAT treatment was necessary to obtain stable transformation with this tissue
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018470930944
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  • 53
    Electronic Resource
    Electronic Resource
    Mitochondria transfer into mouse ova by microinjection (1997)
    Springer
    Transgenic research 6 (1997), S. 379-383 
    Details
    ISSN: 1573-9368
    Keywords: genetic engineering ; heteroplasmy ; mouse ; mitochondria ; mitochondria transfer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A method for mitochondria isolation and interspecific transfer of mitochondria was developed in mice. Mitochondria were isolated from Mus spretus liver samples for microinjection into fertilized ova obtained from superovulated M. musculus domesticus females. Electron microscopic observations of mitochondria preparations used for microinjection demonstrated intact mitochondrial vesicles with little microsomal contamination. Species-specific nested PCR primers complementary to sequence differences in the mitochondrial DNA D-loop region revealed high rates of successful transfer of foreign mitochondria after isolation and injection into zygotes cultured through the blastocyst stage of embryonic development. Of 217 zygotes, 67 survived mitochondria injection and 23 out of 37 zygotes developed were at the blastocyst-stage of embryonic development after 4.5 days of in vitro culture. All 23 of these blastocysts contained detectable levels of foreign mitochondria. These results represent an initial step in developing a model system to study mitochondrial dynamics and development of therapeutic strategies for human metabolic diseases affected by aberrations in mitochondrial function or mutation
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018431316831
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    Electronic Resource
    Matrix attachment regions (MARs) enhance transformation frequency and transgene expression in poplar (1997)
    Springer
    Transgenic research 6 (1997), S. 415-420 
    Details
    ISSN: 1573-9368
    Keywords: GUS ; matrix attachment regions ; Populus ; transformation ; transgene expression ; Agrobacterium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We tested the value of a matrix attachment region (MAR) fragment derived from a tobacco gene for increasing the frequency of Agrobacterium-mediated transformation. A binary vector that carried a GUS reporter gene containing an intron and an nptII gene was modified to contain flanking MAR elements within the T-DNA borders. Vectors containing or lacking MARs were then used to transform tobacco, a readily transformabl e poplar clone (Populus tremula × P. alba), and a recalcitrant poplar clone (Populus trichocarpa × P. deltoides). MARs increased GUS gene expression approximately 10-fold in the two hybrid poplar clones and twofold in tobacco one month after cocultivation with Agrobacterium; MARs also increased the frequency of kanamycin-resistant poplar shoots recovered
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018439518649
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  • 55
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    Electronic Resource
    Bruchid resistance of transgenic azuki bean expressing seed α-amylase inibitor of common bean (1996)
    Springer
    Entomologia experimentalis et applicata 79 (1996), S. 309-315 
    Details
    ISSN: 1570-7458
    Keywords: insect resistance ; genetic engineering ; host specificity ; transgenic plant ; α-amylase inhibitor ; Callosobruchus spp. ; Zabrotes subfasciatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Various species of bruchid beetles including Callosobruchus chinensis, C. maculatus and C. analis cause postharvest damage of azuki bean seeds, an important East Asian grain legume. The α-amylase in the midguts of these insects is inhibited by the α-amylase inhibitor (αAI) present in common bean seeds. Transformation of azuki bean with the αAI gene driven by the promoter of phytohemagglutinin results in high levels of αAI in the seeds and the complete block of bruchid development on the seeds. Zabrotes subfasciatus, a South and Central American bruchid that is a storage pest of common bean, develops normally on the transgenic azuki bean.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00186289
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  • 56
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    Electronic Resource
    Transgenic plant production mediated by Agrobacterium in Indica rice (1996)
    Springer
    Plant cell reports 15 (1996), S. 727-730 
    Details
    ISSN: 1432-203X
    Keywords: Acetosyringone ; Agrobacterium ; Indica rice ; Oryza sativa L. ; Transgenic plants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A reproducible system has been developed for the production of transgenic plants in indica rice using Agrobacterium-mediated gene transfer. Three-week-old scutella calli served as an excellent starting material. These were infected with an Agrobacterium tumefaciens strain EHA101 carrying a plasmid pIG121Hm containing genes for β-glucuronidase (GUS) and hygromycin resistnace (HygR). Hygromycin (50 mg/l) was used as a selectable agent. Inclusion of acetosyringone (50μM) in the Agrobacterium suspension and co-culture media proved to be indispensable for successful transformation. Transformation efficiency of Basmati 370 was 22% which was as high as reported in japonica rice and dicots. A large number of morphologically normal, fertile transgenic plants were obtained. Integration of foreign genes into the genome of transgenic plants was confirmed by Southern blot analysis. GUS and HygR genes were inherited and expressed in R1 progeny. Mendelian segregation was observed in some R1 progeny.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00232216
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  • 57
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    Transient expression of uidA constructs in in vitro onion (Allium cepa L.) cultures following particle bombardment and Agrobacterium-mediated DNA delivery (1996)
    Springer
    Plant cell reports 15 (1996), S. 958-962 
    Details
    ISSN: 1432-203X
    Keywords: Transformation ; particle bombardment ; Agrobacterium ; Allium cepa.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Particle bombardment and Agrobacterium-mediated DNA delivery into immature embryos and microbulbs were used to investigate the expression of the uidA gene in in vitro onion cultures. Both methods were successful in delivering DNA and subsequent uidA expression was observed. Optimal transient β-glucuronidase activity was observed in immature embryos that had been pre-cultured for three days and bombarded at a distance of 3 cm from the stopping plate, under 25 in Hg vacuum, using 900–1300 psi rupture discs. The CaMV35S-uidA gene construct gave five fold higher transient β-glucuronidase activity than the uidA gene construct regulated by any of four other promoters initially chosen for high experession in monocotyledonous tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231596
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  • 58
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    Electronic Resource
    Production of an extracellular polysaccharide byAgrobacterium sp DS3 NRRL B-14297 isolated from soil (1996)
    Springer
    Journal of industrial microbiology and biotechnology 16 (1996), S. 129-133 
    Details
    ISSN: 1476-5535
    Keywords: extracellular polysaccharide ; Agrobacterium ; viscous polysaccharide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A bacterium isolated from soil and identified asAgrobacterium sp produced a water-soluble extracellular polysaccharide capable of producing highly viscous solutions. Gas chromatographic analysis revealed a sugar composition of glucose, galactose and mannose in the molar ratio of 7.5∶2.4∶1, together with 3.7% (w/w) pyruvic acid. Methylation analyses showed the presence of (1→3)-, (1→4)- and (1→6)-linked glucose, (1→3)- and (1→4, 1→6)-linked galactose and a small portion of (1→3)-linked mannose residues. Succinic acid was not present. The molecular weight of the polysaccharide was estimated by light scattering to be 2×106 Da. The viscosity of solutions containing the polysaccharide remained constant from pH 3 to 11, and decreased by 50% when heated from 5 to 55°C. Maximum yield of the polysaccharide, 20 g L−1, was reached in 48 h at 30°C incubation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01570073
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  • 59
    Electronic Resource
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    Antimicrobial peptides fromMirabilis jalapa andAmaranthus caudatus: expression, processing, localization and biological activity in transgenic tobacco (1996)
    Springer
    Plant molecular biology 31 (1996), S. 993-1008 
    Details
    ISSN: 1573-5028
    Keywords: antifungal ; genetic engineering ; precursor processing ; protein sorting ; disease resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cDNAs encoding the seed antimicrobial peptides (AMPs) fromMirabilis jalapa (Mj-AMP2) andAmaranthus caudatus (Ac-AMP2) have previously been characterized and it was found that Mj-AMP2 and Ac-AMP2 are processed from a precursor preprotein and preproprotein, respectively [De Bolleet al., Plant Mol Biol 28:713–721 (1995) and 22:1187–1190 (1993), respectively]. In order to study the processing, sorting and biological activity of these antimicrobial peptides in transgenic tobacco, four different gene constructs were made: a Mj-AMP2wild-type gene construct, a Mj-AMP2 mutant gene construct which was extended by a sequence encoding the barley lectin carboxyl-terminal propeptide, a known vacuolar targeting signal [Bednarek and Raikhel, Plant Cell 3: 1195–1206 (1991)]; an Ac-AMP2wild-type gene construct; and finally, an Ac-AMP2 mutant gene construct which was truncated in order to delete the sequence encoding the genuine carboxyl-terminal propeptide. Processing and localization analysis indicated that an isoform of Ac-AMP2 with a cleaved-off carboxyl-terminal arginine was localized in the intercellular fluid fraction of plants expressing eitherwild-type or mutant gene constructs. Mj-AMP2 was recovered extracellularly in plants transformed with Mj-AMP2wild-type gene construct, whereas an Mj-AMP2 isoform with a cleaved-off carboxyl-terminal arginine accumulated intracellularly in plants expressing the mutant precursor protein with the barley lectin propeptide. Thein vitro antifungal activity of the AMPs purified from transgenic tobacco expressing any of the four different precursor proteins was similar to that of the authentic proteins. However, none of the transgenic plants showed enhanced resistance against infection with eitherBotrytis einerea orAlternaria longipes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040718
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  • 60
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    Electronic Resource
    Agrobacterium tumefaciens-mediated transformation of japonica and indica rice varieties (1996)
    Springer
    Planta 199 (1996), S. 612-617 
    Details
    ISSN: 1432-2048
    Keywords: Agrobacterium ; indica rice ; Inheritance ; Japonica rice ; Oryza ; Transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Genetic transformation of rice (Oryza sativa L.) mediated by Agrobacterium ttumefaciens has been confirmed for japonica varieties and extended to include the more recalcitrant indica varieties. Immature embryos were inoculated with either A. tumefaciens At656 (pCNL56) or LBA4404 (pTOK233). Experimental conditions were developed initially for immature embryos treated with strain At656, based upon both transient and stable β-glucuromdase (GUS) activities. However, plant regeneration following selection on G418 (pCNL56 contained the nptII gene) did not occur. Using the same basic protocol, but inoculating immature embryos of rice with LBA4404 (pTOK233), resulted in efficient (about 27%) production of transgenic plants of the japonica variety, Radon, and an acceptable efficiency (from 1–5%) for the indica varieties IR72 and TCS10. Transformation was based upon resistance to hygromycin (pTOK233 contains the hpt gene), the presence of GUS activity (from the gusA gene), Southern blots for detection of the integrated gusA gene, and transmission of GUS activity to progeny in a Mendelian 3:1 segregation ratio. Southern blots indicated two to three copies of the gene integrated in most transformants. Transgenic plants of both the japonica and indica varieties were self-fertile and comparable in this respect to seed-grown plants. Key factors facilitating the transformation of rice by Agrobacterium tumefaciens appeared to be the use of embryos as the expiant, the use of hygromycin as the selection agent (which does not interfere with rice regeneration), the presence of extra copies of certain vir genes on the binary vector of pTOK233, and maintaining high concentrations of acetosyringone for inducing the vir genes during co-cultivation of embryos with Agrobacterium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195194
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  • 61
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    An agenda for future potato research (1996)
    Springer
    Potato research 39 (1996), S. 387-394 
    Details
    ISSN: 1871-4528
    Keywords: genetic engineering ; sustainable production ; breeding ; resistance processing ; storage ; priorities
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The world is changing, and the rate of change is accelerating, nowhere moreso than in the pace of scientific discovery and the advance of technology. The last thirty years have also seen substantial global changes in potato production which are likely to continue if current projections are correct. Climate change is bound to affect local weather patterns, which will influence both the epidemiology of pests and pathogens and broaden their geographic range. An agenda for future research will of necessity include much of the current agenda; research into more sustainable systems; research into new and novel resistances to biotic and abiotic constraints, combining modern cell and molecular-based technologies with classical breeding approaches and research into the genetic and biochemical bases of low temperature sweetening and dormancy control, that should lead to varieties with superior storage characteristics, particularly for processing. However, a future agenda has to retain some flexibility and a component of speculative research. Perhaps potatoes could become a source of industrial feedstock or pharmaceuticals, perhaps there is a place for cultivars produced by botanic seed in Europe? The exciting thing about research is that we cannot always predict where it will lead, and a future agenda must not curb the enthusiasm of any young scientist by too rigidly adhering to that suggested here. it is essential that scientific options are kept open.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02357944
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    General resistance against potato virus Y introduced into a commercial potato cultivar by genetic transformation with PVYN coat protein gene (1996)
    Springer
    Potato research 39 (1996), S. 271-282 
    Details
    ISSN: 1871-4528
    Keywords: Pathogen derived resistance ; genetic engineering ; Solanum tuberosum L
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Transgenic cv. Folva potato plants expressing the coat protein gene of potato virus Y strain N (PVYN) were produced usingAgrobacterium tumefaciens mediated transformation. Forty independent transformants were selected for resistance screening. Four clones showed complete resistance to mechanical inoculation with all the five PVY isolates tested: the PVYN isolate from which the coat protein gene was derived, two PVYO isolates, and two PVYNTN isolates. Two of the fully resistant clones contained only one copy of the transgene, demonstrating that it is possible by genetic engineering to obtain highly virus resistant potato clones that can also be useful in future breeding programmes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02360919
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    Electronic Resource
    Sequence and characterisation of a ribosomal RNA operon from Agrobacterium vitis (1996)
    Springer
    Molecular genetics and genomics 251 (1996), S. 99-107 
    Details
    ISSN: 1617-4623
    Keywords: Key words Ribosomal genes ; Agrobacterium ; Evolution ; 23S rRNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  One of the four ribosomal RNA operons (rrnA) from the Agrobacterium vitis vitopine strain S4 was sequenced. rrnA is most closely related to the rrn operons of Bradyrhizobium japonicum and Rhodobacter sphaeroides and carries an fMet-tRNA gene downstream of its 5S gene, as in the case of R. sphaeroides. The 16S rRNA sequence of S4 differs from the A. vitis K309 type strain sequence by only one nucleotide, in spite of the fact that S4 and K309 have very different Ti plasmids. The predicted secondary structure of the S4 23S rRNA shows several features that are specific for the alpha proteobacteria, and an unusual branched structure in the universal B8 stem. The 3′ ends of the three other rrn copies of S4 were also cloned and sequenced. Sequence comparison delimits the 3′ ends of the four repeats and defines two groups: rrnA/rrnB and rrnC/rrnD.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02174350
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    Transformation ofBrassica oleracea L.: a critical review (1996)
    Springer
    Molecular breeding 2 (1996), S. 185-210 
    Details
    ISSN: 1572-9788
    Keywords: Brassica oleracea ; Agrobacterium ; transformation ; direct gene transfer ; regeneration ; virulence ; flowering ; rol genes ; transgene expression ; transgene inactivation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Brassica oleracea is a highly polymorphic species encompassing a wide range of important vegetable and fodder crops. Gene transfer into cultivated forms of this species requires reproducible and efficient methods for genetic transformation and plant regeneration. In this review, we have collated the research experience on transformation ofB. oleracea to highlight the problems encountered. Most research effort has been directed at developingAgrobacterium-mediated transformation methods with relatively little emphasis to date on direct gene transfer techniques. Common procedures for the transformation ofB. oleracea have not emerged, due to the inherent variability between and amongst genotypes. Future progress would be facilitated by the use of genetically fixed material, such as double-haploid or inbred lines, to reduce variation of response within genotypes and would avoid the need for cultivar-specific transformation protocols if responsive lines amenable to crossing with cultivated forms could be identified. The principal difficulties relate to combining efficient plant regeneration with gene transfer. Methods that enhance bacterial virulence and increase the proportion of cells susceptible to transformation and competent for regeneration are discussed. Inefficient selection is a major cause of poor transformation frequencies inB. oleracea and has resulted in the regeneration of chimeric plants uponAgrobacterium tumefaciens-mediated transformation. Promising results have been obtained withAgrobacterium rhizogenes-mediated transformation but the impact of therol genes on flowering of primary transformants has not yet been fully assessed. Strategies to reduce the deleterious effects of therol genes on flowering are discussed. Few agronomically useful characters have been introduced, the majority of research having been confined to the introduction of marker and reporter genes; possible candidate genes are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00564197
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    Electronic Resource
    Sequence and characterisation of a ribosomal RNA operon fromAgrobacterium vitis (1996)
    Springer
    Molecular genetics and genomics 251 (1996), S. 99-107 
    Details
    ISSN: 1617-4623
    Keywords: Ribosomal genes ; Agrobacterium ; Evolution ; 23S rRNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract One of the four ribosomal RNA operons (rrnA) from theAgrobacterium vitis vitopine strain S4 was sequenced.rrnA is most closely related to therrn operons ofBradyrhizobium japonicum andRhodobacter sphaeroides and carries an fMet-tRNA gene downstream of its 5S gene, as in the case ofR. sphaeroides. The 16S rRNA sequence of S4 differs from theA. vitis K309 type strain sequence by only one nucleotide, in spite of the fact that S4 and K309 have very different Ti plasmids. The predicted secondary structure of the S4 23S rRNA shows several features that are specific for the alpha proteobacteria, and an unusual branched structure in the universal B8 stem. The 3′ ends of the three otherrrn copies of S4 were also cloned and sequenced. Sequence comparison delimits the 3′ ends of the four repeats and defines two groups:rrnA/rrnB andrrnC/rrnD.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02174350
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  • 66
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    Corresponding 16S rRNA gene segments in Rhizobiaceae and Aeromonas yield discordant phylogenies (1996)
    Springer
    Plant and soil 186 (1996), S. 69-74 
    Details
    ISSN: 1573-5036
    Keywords: Agrobacterium ; population genetics ; Rhizobium ; systematics ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Previous evidence has indicated that the 16S rRNA genes in certain species of Aeromonas may have a history of lateral transfer and recombination. A comparative analysis of patterns of 16S nucleotide sequence polymorphism among species of Rhizobium and Agrobacterium was conducted to determine if there is similar evidence for chimeric 16S genes in members of the Rhizobiaceae. Results from phylogenetic analyses and comparison of patterns of nucleotide sequence polymorphism in portions of rhizobial 16S genes revealed the same type of segment-dependent polymorphic site partitioning that was previously reported for Aeromonas. These results support the hypothesis that certain 16S segments in rhizobia may have a history of lateral transfer and recombination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00035057
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  • 67
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    Identification of Agrobacterium and Rhizobium species based on cellular fatty acid composition (1996)
    Springer
    Plant and soil 184 (1996), S. 143-158 
    Details
    ISSN: 1573-5036
    Keywords: Agrobacterium ; FAME ; fatty acid analysis ; rapid identification ; Rhizobium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The increasing number of phylogenetically defined species in the genera Agrobacterium, Rhizobium and Sinorhizobium suggests a need for a rapid identification method which will distinguish between these species. We have examined 65 strains of Agrobacterium representing: A. tumefacies, (34); A. rhizogenes, (16) A. vitis, (10) A. rubi (2) and some unclassified strains, and 150 strains of Rhizobium and Sinorhizobium representing: R. etli (21); R. galegae (20); R. huakuii (17); R. leguminosarum (20); R. loti (16); R. topici (18); S. fredii (19); and S. meliloti (20). Fatty acid methyl esters (FAME) were obtained from each strain, as previously described, and analysed by gas-chromatography using the MIDI Hewlett-Packard Microbial Identification System (MIS). Fatty acid profiles were recorded, characteristic fatty acids noted and the overall similarities between fatty acid profiles for each species calculated. Relationships between species were also derived from the fatty acid data by principal component analysis. This showed overlapping clusters for strains of R. leguminosarum and R. etli, R. topici and A. rhizogenes and S. fredii and S. meliloti within one supercluster. Strains of A. tumefaciens, A rubi, A. vitis and R. galegae formed a second supercluster while R. loti and R. huakuii strains formed a third cluster well separated from all the other strains. The fatty acid profiles were used to correctly identify at least 94% of the strains representing each species in the collection except R. etli. R. etli strains (23.8%) were misidentified as R. leguminosarum. This was attributed to the high similarity (44.7%) between R. etli and R. leguminosarum. It is concluded that whole cell fatty acid analysis should form part of the polyphasic description of new species of root nodule bacteria, with the proviso that growth conditions and analytical methods be carefully standardized. It is suggested that FAME-MIS system and the database we have compiled provide a basis for future development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00029284
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    Production of multidomain complement glycoproteins in insect cells (1996)
    Springer
    Cytotechnology 20 (1996), S. 279-288 
    Details
    ISSN: 1573-0778
    Keywords: baculovirus ; complement activation ; genetic engineering ; mosaic protein ; serine-protease ; zymogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00350407
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  • 69
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    Agrobacterium-mediated transformation of Javanica rice (1996)
    Springer
    Molecular breeding 2 (1996), S. 267-276 
    Details
    ISSN: 1572-9788
    Keywords: Agrobacterium ; Javanica rice ; regeneration ; rice ; TAIL-PCR ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Difficulties frequently encountered using direct DNA transfer methods for transformation of Javanica varieties of rice (Oryza sativa L.) have limited the application of biotechnology to these varieties. We now reportAgrobacterium-mediated transformation of Javanica cultivars Gulfmont and Jefferson that are, respectively, widely used or about to enter commercial cultivation in the southern USA. Vigorous, phenotypically normal, fertile plants expressing both the selectable marker and the gene of interest were obtained. Southern analysis showed that only one or two copies of the T-DNA insert were present. Sequence analysis of right border fragments of one line confirmed that insertion was into a coding region of rice nuclear DNA. This analysis also revealed the presence of relatively short regions of permuted T-DNA border sequences, similar to those found afterAgrobacterium-mediated transformation of dicots. Progeny analysis of lines bearing two copies showed co-segregation, indicating that they were located relatively closely on the same chromosome. The introduced genes were transmitted to the R1 and R2 generations in a Mendelian fashion, confirming the suitability of this approach for biotechnological improvement of elite rice cultivars.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00564204
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  • 70
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    Genetic engineering for resistance to bacteria in transgenic plants by introduction of foreign genes (1996)
    Springer
    Molecular breeding 2 (1996), S. 297-305 
    Details
    ISSN: 1572-9788
    Keywords: transgenic plants ; resistance ; phytopathogenic bacteria ; plant breeding ; genetic engineering ; potato ; tobacco
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00437908
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    Genetic engineering to contain the Vitreoscilla hemoglobin gene enhances degradation of benzoic acid by Xanthomonas maltophilia (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 49 (1996), S. 101-105 
    Details
    ISSN: 0006-3592
    Keywords: Xanthomonas maltophilia ; benzoic acid ; Vitreoscilla hemoglobin gene ; genetic engineering ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Xanthomonas maltophilia was transformed with the gene encoding Vitreoscilla (bacterial) hemoglobin, vgb, and the growth of the engineered strain was compared with that of the untransformed strain using benzoic acid as the sole carbon source. In general, growth of the engineered strain was greater than that of the untransformed strain; this was true for experiments using both overnight cultures and log phase cells as inocula, but particularly for the latter. In both cases the engineered strain was also more efficient than the untransformed strain in converting benzoic acid into biomass. © 1996 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
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    Release of genetically modified micro-organisms into the environment (1996)
    Chichester : Wiley-Blackwell
    Journal of Chemical Technology AND Biotechnology 65 (1996), S. 5-14 
    Details
    ISSN: 0268-2575
    Keywords: GMOs ; environment ; release ; genetic engineering ; gene transfer ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Biotechnology in general, and recombinant DNA technology in particular, has the capacity to change the health and wealth of every individual, but like other major advances in science and technology such as nuclear power and electronics it can also be exploited to mankind's detriment. For this reason and the fact that recombinant DNA technology involves altering the molecules encoding life itself, the subject has given rise to a high level of public debate. Centuries of experience with the release of conventional micro-organisms for sewage treatment, agriculture and food production have shown that the release of large numbers of foreign organisms into an environment does not necessarily cause ecological damage. In fact few of these organisms survive for long periods. The threat of horizontal gene transfer from recombinant organisms to indigenous ones is however very real and mechanisms exist whereby, at least theoretically, any genetically engineered trait can be transferred to any prokaryotic organism and many eukaryotic ones. The rapid spread of antibiotic-resistant organisms since the widespread introduction of antibiotics graphically demonstrates that such a threat is real. There have now been several experiments to determine the effect of environmental release of micro-organisms, both in enclosed areas and in unenclosed sites. Proposals for the use of genetically modified micro-organisms that contain specific gene deletions have had a relatively smooth passage through government approval agencies and public enquiries and some products have been approved for commercial use. In addition a strain of bakers' yeast with an altered control element has also been approved for commercial use in the UK. Genetically modified viruses, especially those containing foreign genes have not received such favourable treatment and have been the subject of heated national and international debate. Many microbiologists are convinced, however, that the use and release of carefully constructed genetically engineered organisms will result in significant benefit, but with little risk to the environment. Ecologists, however, are not so sanguine and in the current ‘green’ political atmosphere their opinions are very influential. Thus most developed countries now have in force a series of very cautious regulations and guidelines for the release of genetically modified micro-organisms.
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    Electronic Resource
    Biotechnology is compatible with sustainable agriculture (1995)
    Springer
    Journal of agricultural and environmental ethics 8 (1995), S. 112-125 
    Details
    ISSN: 1573-322X
    Keywords: agribusiness ; biotechnology ; crop adaptation ; crop diversity ; crop management ; crop varieties ; disease resistance ; environment ; genetic engineering ; holistic agriculture ; insect resistance ; new technology ; plant breeding ; societal responsibility ; sustainable agriculture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Philosophy
    Notes: Abstract Biotechnology can provide appropriate new tools for use in solution of specific problems in sustainable agriculture. Its usefulness will depend in large part on the degree to which sustainable agriculturists understand the utility of biotechnology and apply it toward ends they deem important. Biotechnology can give little assistance to sustainable agriculture in the short term. It can be more useful in the medium term, and it could be highly useful in the long term as an integral part of the art and science of plant breeding and other components of sustainable agriculture systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02251875
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  • 74
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    Electronic Resource
    5′-Regulatory region of Agrobacterium tumefaciens T-DNA gene 6b directs organ-specific, wound-inducible and auxin-inducible expression in transgenic tobacco (1995)
    Springer
    Plant molecular biology 29 (1995), S. 1299-1304 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium ; gene 6b ; phytohormonal regulation of expression ; T-DNA promoter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The regulatory activity of a 826 bp DNA fragment located upstream of the pTiBo542 TL-DNA gene 6b coding region was analysed in transgenic tobacco, using β-glucuronidase (gus) as a reporter gene. The region was shown to drive organ-specific, wound- and auxin-inducible expression of the reporter, the effect being dependent on the type and concentration of auxin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00020470
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  • 75
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    Electronic Resource
    The three-dimensional structure of vascular tissues in Agrobacterium tumefaciens-induced crown galls and in the host stems of Ricinus communis L. (1995)
    Springer
    Planta 196 (1995), S. 597-605 
    Details
    ISSN: 1432-2048
    Keywords: Agrobacterium ; Crown gall ; Fiber ; Phloem anastomoses ; Phloem and xylem differentiation ; Phytohormones (auxin, cytokinin, ethylene, gibberellin) ; Ray differentiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The three-dimensional pattern of phloem and xylem in 10-d-to two-month-old tumors induced by Agrobacterium tumefaciens (C58) and in adjacent Ricinus communis L. stem tissues was studied in thick sections by clearing with lactic acid and by staining with lacmoid. The crown galls contained two types of vascular strands: treelike branched bundles, which developed towards the tumor surface in fast-growing regions, and globular bundles in the slowly developing parts. Both types of vascular bundles contained xylem and phloem and were continuous with the vascular system of the host plant. The tumor bundles were interconnected by a dense net of phloem anastomoses, consisting of sieve tubes but no vessels. These vascular patterns reflect the apparent synthesis sites, concentration gradients and flow pathways of the plant hormones additionally produced in the tumors upon expression of the T-DNA-encoded genes. The A. tumefaciens-induced crown gall affected vascular differentiation in the host stem. In the basipetal direction, the tumor induced more xylem differentiation directly below it, where the crown-gall bundles joined the vascular system of the host. In the centripetal direction, the crown gall caused the development of pathologic xylem characterized by narrow vessels, giant rays and absence of fibers. On the other hand, most probably as a consequence of its gibberellic acid content, the host plant stimulated a local differentiation of regenerative phloem and xylem fibers with unique ramifications, only at the base of the tumor. However, fibers were absent from the main body of the crown gall. The study shows that A. tumefaciens-induced crown galls are characterized by a sophisticated network of vascular tissues in the tumor and are accompanied by a perturbated vessel system in the host. The hormonal mechanisms controlling vascular differentiation in the tumor and neighboring host tissues are discussed. In addition, the “gall constriction hypothesis” is proposed for explaining the mechanism which gives priority in water supply to the growing gall over the host shoot.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203661
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  • 76
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    The effect of auxin on cytokinin levels and metabolism in transgenic tobacco tissue expressing an ipt gene (1995)
    Springer
    Planta 196 (1995), S. 84-94 
    Details
    ISSN: 1432-2048
    Keywords: Agrobacterium ; Auxin ; Cytokinin metabolism ; Cytokinin oxidase ; ipt gene ; Nicotiana (cytokinin)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The ipt gene from the T-DNA of Agrobacterium tumefaciens was transferred to tobacco (Nicotiana tabacum L.) in order to study the control which auxin appears to exert over levels of cytokinin generated by expression of this gene. The transgenic tissues contained elevated levels of cytokinins, exhibited cytokinin and auxin autonomy and grew as shooty calli on hormone-free media. Addition of 1-naphthylacetic acid to this culture medium reduced the total level of cytokinins by 84% while 6-benzylaminopurine elevated the cytokinin level when added to media containing auxin. The cytokinins in the transgenic tissue were labelled with 3H and auxin was found to promote conversion of zeatin-type cytokinins to 3H-labelled adenine derivatives. When the very rapid metabolism of exogenous [3H]zeatin riboside was suppressed by a phenylurea derivative, a noncompetitive inhibitor of cytokinin oxidase, auxin promoted metabolism to adenine-type compounds. Since these results indicated that auxin promoted cytokinin oxidase activity in the transformed tissue, this enzyme was purified from the tobacco tissue cultures. Auxin did not increase the level of the enzyme per unit tissue protein, but did enhance the activity of the enzyme in vitro and promoted the activity of both glycosylated and non-glycosylated forms. This enhancement could contribute to the decrease in cytokinin level induced by auxin. Studies of cytokinin biosynthesis in the transgenic tissues indicated that trans-hydroxylation of isopentenyladenine-type cytokinins to yield zeatin-type cytokinins occurred principally at the nucleotide level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00193221
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  • 77
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    Variability in the response toPseudomonas solanacearum of transgenic lines of potato carrying a cecropin gene analogue (1995)
    Springer
    Potato research 38 (1995), S. 371-378 
    Details
    ISSN: 1871-4528
    Keywords: bacterial wilt ; resistance ; transformation ; Agrobacterium ; S. tuberosum L. ; transgenic plant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Transgenic potato plants of cv. Désirée carrying an antibacterial gene, coding for a cecropin lytic peptide analogue, were inoculated with a virulent strain ofPseudomonas solanacearum under controlled conditions. The disease index scored during three repeated infection trials indicated an increased variability in plant response among the transgenic lines which gave either a more susceptible or a more resistant response to the pathogen when compared with untransformed Désirée. Immunity toP. solanacearum was not observed, but it was possible to select a group of transgenic lines that showed resistance levels and disease development curves comparable to the field resistant cv. Cruza 148.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02357742
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  • 78
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    Electronic Resource
    Rapid micropreps and minipreps of Ti plasmids and binary vectors fromAgrobacterium tumefaciens (1995)
    Springer
    Transgenic research 4 (1995), S. 349-351 
    Details
    ISSN: 1573-9368
    Keywords: Agrobacterium ; Ti plasmid ; binary vector ; minipreparation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A simple and versatile procedure has been developed for the isolation of both large helper/Ti plasmids and binary vectors fromAgrobacterium tumefaciens. Using a slightly modified alkaline lysis protocol, intact plasmid can be recovered from cultures grown in standard micro-centrifuge tubes or culture tubes in sufficient yield and purity to allow for restriction analysis on ethidium bromide stained gels of the 〉200 kb Ti plasmid DNA. Contamination by chromosomal DNA is minimal and there is thus no need for isopycnic gradient purification. This same procedure can be combined with a high temperature treatment (37°C) and antibiotic selection to generate preparations containing binary vector DNA that are virtually free of interfering Ti plasmid DNA. Restriction patterns produced from these binary vector DNA preparations are unambiguous and therefore preliminary screening by Southern hybridization can be eliminated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01972532
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  • 79
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    Electronic Resource
    Expression of giant silkmoth cecropin B genes in tobacco (1995)
    Springer
    Transgenic research 4 (1995), S. 132-141 
    Details
    ISSN: 1573-9368
    Keywords: antibacterial ; bacterial disease resistance ; cecropin ; genetic engineering ; plant transformation ; protease degradation ; transgenic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cecropin B is a small antibacterial peptide from the giant silkmothHyalophora cecropia. To reveal the potential of this peptide for engineering bacterial disease resistance into crops, several cecropin B gene constructs were made either for expression in the cytosol or for secretion. All constructs were cloned in a plant expression vector and introduced in tobacco viaAgrobacterium tumefaciens. A cDNA-derived cecropin B gene construct lacking the amino-terminal signal peptide was poorly expressed in transgenic plants at the mRNA level, whereas plants harbouring a full-length cDNA-derived construct containing the insect signal peptide, showed increased cecropin B-mRNA levels. Highest expression was found in plants harbouring a construct with a plant-gene-derived signal peptide. In none of the transgenic plants could the cecropin B peptide be detected. This is most likely caused by breakdown of the peptide by plant endogenous proteases, since a chemically synthesized cecropin B peptide was degraded within seconds in various plant cell extracts. This degradation could be prevented by the addition of specific protease inhibitors and by boiling the extract prior to adding the peptide. In addition, anionic detergents, in contrast to cationic, zwitter-ionic or non-ionic detergents, could prevent this degradation. Nevertheless, transgenic tobacco plants were evaluated for resistance toPseudomonas solanacearum, the causal agent of bacterial wilt of many crops, andP. syringae pv.tabaci, the causal agent of bacterial wildfire, which are highly susceptible to cecropin Bin vitro. No resistance was found. These experiments indicate that introduction and expression of cecropin B genes in tobacco does not result in detectable cecropin B protein levels and resistance to bacterial infections, most likely due to degradation of the protein by endogenous proteases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01969415
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  • 80
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    Electronic Resource
    Cell competence forAgrobacterium-mediated DNA transfer inPisum sativum L. (1995)
    Springer
    Transgenic research 4 (1995), S. 184-191 
    Details
    ISSN: 1573-9368
    Keywords: competence ; transient ; transformation ; Agrobacterium ; grain legume ; histochemical GUS-detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Distribution and properties of pea (Pisum sativum L.) cells, competent forAgrobacterium-mediated transformation were analysed byin situ histochemical detection of GUS (β-glucuronidase) activity, 4 d after inoculation with engineeredAgrobacterium tumefaciens. The vector system consisted of the hypervirulent disarmed strain EHA101 and the binary plasmid pIBGUS, carrying an intron-containing, 35S-promotor drivengusA (oruidA) gene and two selectable marker genes. Cells competent for transformation were mainly restricted to the dedifferentiating cells neighbouring the vascular system of cotyledon and epicotyl explants. A standardized assay was developed, allowing determination and quantification of factors influencing number and distribution of competent cells. In etiolated seedlings, competence for transformation decreased with the distance of the epicotyl explant from the shoot apex and was specifically induced by the exogenous application of auxins. Transient expression ofgusA afterAgrobacterium-mediated DNA transfer was dramatically reduced upon application of cell-cycle and DNA replication inhibitors aphidicolin, colchicine and nalidixic acid. GUS expression after direct DNA transfer of double-stranded plasmid DNA (via PEG into protoplasts or via particle bombardment of epicotyl segments) was independent of cell-division/DNA replication. A GUS-positive mutant of EHA101 was constructed to allowin situ analysis of attaching bacteria within the plant tissue. Attachment and invasion was inhibited by well-developed cuticula but was restored after chloroform treatment of the tissue surface. Moreover, no correlation was found between distribution of attaching bacteria and the pattern of transformation-competent cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01968783
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  • 81
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    Ti plasmid-encoded octopine and nopaline catabolism in Agrobacterium: specificities of the LysR-type regulators OccR and NocR, and protein-induced DNA bending (1995)
    Springer
    Molecular genetics and genomics 249 (1995), S. 102-110 
    Details
    ISSN: 1617-4623
    Keywords: Agrobacterium ; Ti plasmid ; Activator ; Opines ; LysR family
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The occ and noc regions in octopine and nopaline Ti plasmids, respectively, are responsible for the catabolism of octopine and nopaline in Agrobacterium. The functions are activated in the presence of the opines by OccR and NocR, two related regulatory proteins, and the promoters contain common sequence motifs. We have investigated heterologous interactions between the regulators and the promoters. Previous experiments using all possible heterologous combinations of opines, regulators, and promoters in vivo had demonstrated that only the combination of nopalme, NocR, and the occ promoter led to limited promoter activation. We now show that OccR and NocR bind to the heterologous promoters in vitro and in vivo. The weak or non-existent promoter activation actually observed could be explained by the assumption that OccR and NocR use different activation mechanisms; we investigated protein-induced DNA bending because of reports that the two regulators differ in this respect. Analysis with a bending vector showed that both OccR and NocR induced a DNA bend that is relaxed in the presence of the respective opine. The data suggest that subtle differences in regulator/promoter interactions are responsible for the inactivity of the heterologous combinations. Investigations with a chimeric NocR/OccR protein indicated that it induced a DNA bend in both promoters. No opine-induced relaxation was detectable with the hybrid, and the inducible promoter was not activated. These findings suggest that bend relaxation may be an integral part of promoter activation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00290241
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  • 82
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    New plant promoter and enhancer testing vectors (1995)
    Springer
    Molecular breeding 1 (1995), S. 419-423 
    Details
    ISSN: 1572-9788
    Keywords: binary vectors ; gus ; T-DNA ; Agrobacterium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We describe here a set of binary vectors suitable forAgrobacterium-mediated gene transfer and specially designed for studying plant promoters. These vectors are based on the use of thegus reporter gene, contain multiple unique restriction sites upstream of thegus gene, and minimal promoters for testing the effect of enhancers or activator elements. In addition, an intron-containinggus (uidA) gene was introduced into one of these vectors in order to examine reporter gene activity in tissues whereAgrobacterium contamination may be a problem or in transient expression assays.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01248419
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  • 83
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    Procedural justice as a contested concept: Sociological remarks on the group value model (1995)
    Springer
    Social justice research 8 (1995), S. 175-195 
    Details
    ISSN: 1573-6725
    Keywords: systems theory ; procedural justice ; technology assessment ; genetic engineering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Political Science , Sociology
    Notes: Abstract The group value model by Lind and Tyler has had a major impact on procedural justice research. After critically examining the model, the author proposes that its underlying idea be reformulated at a more general level. The theory of autopoietic systems provides the background for an attempt to depict procedural justice as a mode for the self-description of social systems, a concept that the author relates to procedural structures that have been empirically shown to exist. Two cases from the field of genetic engineering are cited in this context.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02334690
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  • 84
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    Plant genetic engineering for crop improvement (1995)
    Springer
    World journal of microbiology and biotechnology 11 (1995), S. 449-460 
    Details
    ISSN: 1573-0972
    Keywords: Bioreactor plants ; crop improvement ; genetic engineering ; molecular flower breeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Plant genetic engineering has long since left its experimental stage: transgenic plants with resistance to viruses, bacteria, fungi, various pests and abiotic stresses have already been released in their hundreds. Transgenic plants can produce better fruits and food of higher quality than wild-types, and can be used as bioreactors for the synthesis of pharmaceutically important compounds. This review portrays some of the achievements in this field of plant molecular biology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00364620
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  • 85
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    The potential of biotechnology in temperate agroforestry practices (1995)
    Springer
    Agroforestry systems 32 (1995), S. 29-44 
    Details
    ISSN: 1572-9680
    Keywords: genetic engineering ; marker-aided selection ; molecular diagnostics ; plant tissue culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Technologies in forest molecular biology and tissue culture could play an increasing role in the choice of genotypes for successful establishment of agroforestry practices. Research areas such as micropropagation, somatic embryogenesis, genetic engineering, marker-aided selection, and molecular diagnostics are merging with traditional forest biological studies to help identify and produce better-suited trees for agroforestry plantings. A combination of classical and molecular biological research could be used to improve pest and stress resistance of selected genotypes, modify structure and function, and monitor pests of trees. This merger of approaches, as well as continued technological development, could accelerate the production and selection of suitable tree genotypes for agroforestry plantings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00713846
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  • 86
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    Biotechnology is not compatible with sustainable agriculture (1995)
    Springer
    Journal of agricultural and environmental ethics 8 (1995), S. 98-111 
    Details
    ISSN: 1573-322X
    Keywords: biotechnology ; sustainable agriculture ; subsistence ; women farmers ; genetic engineering ; agricultural ethics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Philosophy
    Notes: Abstract Biotechnology increases commercialization of food production, which competes with food for home use. Most people in the world grow their own food, and are more secure without the mediation of the market. To the extent that biotechnology enhances market competitiveness, world food security will decrease. This instability will result in a greater gap between rich and poor, increasing poverty of women and children, less ability and incentive to protect the environment, and greater need for militarization to maintain order. Therefore, biotechnology should be discouraged. An active program to protect and strengthen local food production and to decrease reliance on industrial agriculture should be promoted.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02251874
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  • 87
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    Efficient transformation and regeneration of carnation cultivars usingAgrobacterium (1995)
    Springer
    Molecular breeding 1 (1995), S. 283-293 
    Details
    ISSN: 1572-9788
    Keywords: Agrobacterium ; carnation ; Dianthus caryophyllus ; regeneration ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We have developed an efficient method for transformation and regeneration of plants from carnation,Dianthus caryophyllus L. Whole leaves fromin vitro shoot cultures were mixed withAgrobacterium, cocultivated for 5 days and then plated on 2 µg/l chlorsulfuron (CS). Regenerated shoots and shoot clusters were divided into smaller sections and plated on 3 µg/l CS for selection to produce fully transformed shoots. Geneticin (G418) and kanamycin used were not as effective selective agents as CS. All regenerated shoots were vitrified. These were normalized, rooted and transferred to the greenhouse. 100% of regenerated plants were transformed based on rooting assay, GUS assay, PCR and Southern analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02277428
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  • 88
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    Genetically engineered charge modifications to enhance protein separation in aqueous two-phase systems: Charge directed partitioning (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 46 (1995), S. 62-68 
    Details
    ISSN: 0006-3592
    Keywords: aqueous two-phase systems ; β-galactosidase ; T4 lysozyme ; partitioning ; charge modifications ; genetic engineering ; polymers ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This report continues or examination of the effect of genetically engineered charge modifications on the partitioning behavior of proteins in aqueous two-phase extration. The genetic modifications consisted of the fusion of charged peptide tails to β-galactosidase and charge-change point mutations to T4 lysozyme. Our previous article examined the influence of these charge modifications on partitioning as a function of interfacial potential difference. In this study, we examined charge directed partitioning behavior in PEG/dextran systems containing small amounts of the charged polymers diethylaminoethyl-dextran (DEAE-dextran) or dextran sulfate. The best results were obtained when attractive forces between the protein and polymer were present. Nearly 100% of the β-galactosidase, which carries a net negative charge, partitioned to the DEAE-dextran-rich phase regardless of whether the phase was dextran or PEG. In these cases, cloudiness of the protein-rich phases suggest that strong charge interactions resulted in protein/polymer aggregation, which may have contributed to the extreme partitioning. Unlike the potentialdriven partitioning reported previously, consistent partitioning trends were observed as a result of the fusion tails, with observed shifts in partition coefficient (Kp) of up to 37-fold. However, these changes could not be solely attributed to charge-based interactions. Similarly, T4 lysozyme, carrying a net positive charge, partitioned to the dextran sulfate-containing phase, and displayed four- to sevenfold shifts in Kp as a result of the point mutations. These shifts were two to four times stronger than those observed for potential driven partitioning. Little effect on partitioning was observed when the protein and polymer had the same charge, with the exception of β-galactosidase with polyarginine tails. The high positive charge density of these tails provided for a localized interaction with the dextran sulfate, and resulted in 2- to 15-fold shifts in Kp. © 1995 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260460109
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  • 89
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    Targeting of heterologous membrane proteins into proliferated internal membranes in Saccharomyces cerevisiae (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 11 (1995), S. 913-928 
    Details
    ISSN: 0749-503X
    Keywords: fusion-gene expression ; protein targeting ; genetic engineering ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Overproduction of chimeric proteins containing the HMG2/1 peptide, which comprises the seven transmembrane domains of Saccharomyces cerevisiae 3-hydroxy-3-methylglutaryl-CoA reductase isozymes 1 and 2, has previously been observed to induce the proliferation of internal endoplasmic reticulum-like membranes. In order to exploit this amplified membrane surface area for the accommodation of heterologous microsomal proteins, we fused sequences coding for human cytochrome P4501A1 (CYP1A1) to sequence encoding the HMG2/1 peptide and expressed the hybrid genes in yeast. The heterologous hybrid proteins were targeted into strongly proliferated membranes, as shown by electron microscopic and immunofluorescent analysis. Fusion proteins comprising the whole CYP1A1 polypeptide (HMG2/1-CYP1A1) exhibited 7-ethoxyresorufin-O-deethylase activity, whereas fusion proteins lacking the N-terminal 56 amino acids of CYP1A1 (HMG2/1-ΔCYP1A1) were inactive and appeared to be unable to incorporate protoheme. Similar amounts of heterologous protein were detected in cells expressing HMG2/1-CYP1A1, HMG2/1-ΔCYP1A1 and CYP1A1, respectively. Replacement of the N-terminal membrane anchor domain of human NADPH-cytochrome P450 oxidoreductase by the HMG2/1 peptide also resulted in a functional fusion enzyme, which was able to interact with HMG2/1-CYP1A1 and the yeast endogenous P450 enzyme lanosterol-14α-demethylase.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/yea.320111003
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  • 90
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    Transformation of lily by Agrobacterium (1955)
    Springer
    Euphytica 85 (1955), S. 97-100 
    Details
    ISSN: 1573-5060
    Keywords: Agrobacterium ; transformation ; lily ; β-glucuronidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Lily cv. Harmony was inoculated with several Agrobacterium strains to study its susceptibility to Agrobacterium infection and transformation. Tumorous tissue formation on inoculated stem internodes of sterile-grown plantlets, as well as expression of a β-glucuronidase marker gene interrupted by an intron in cells of inoculated stem nodes, indicate that the monocotyledon Lilium is a host for Agrobacterium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023935
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  • 91
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    A study of different (CaMV 35S and mas) promoter activities and risk assessment of field use in transgenic rapeseed plants (1955)
    Springer
    Euphytica 85 (1955), S. 411-416 
    Details
    ISSN: 1573-5060
    Keywords: Agrobacterium ; Brassica napus ; CaMV 35S promoter ; mas promoter ; gene expression ; risk assessment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Gene fusions between the β-glucuronidase (GUS) reporter gene and the promoters of the cauliflower mosaic virus 35S RNA transcript (CaMV 35S) and the mannopine synthase (mas) genes were introduced into rapeseed varieties via Agrobacterium-mediated transformation. Fluorometric assay of β-glucuronidase activity indicated different expression patterns for the two promoters. In seedlings, the CaMV 35S promoter had maximum activity in the primary roots, while the mas promoter was most active in the cotyledons. Etiolated seedlings cultured in the dark showed reduced activity of the mas promoter. Before vernalization at the rosette stage, both promoters were more active in older plant parts than in younger ones. At this stage the highest activity was recorded in cotyledons. After the plants had bolted reduced promoter function was detected in the upper parts of the transformed plants. Both promoters were found to be functional in the majority of the studied organs of transgenic rapeseed plants, but the promoter activity varied considerably between the organs at different developmental stages. The ability of pollen to transfer the introduced genes to other varieties and related species (e.g. Brassica napus and Diplotaxus muralis) by cross-pollination was studied in greenhouse experiments, and field trials were carried out to estimate the distance for biologically-relevant gene dispersal. In artificial crossing, the introduced marker gene was transferable into other varieties of Brassica napus. In field trials, at a distance of 1 metre from the source of transgenic plants, the frequency of an outcrossing event was relatively high (10-3). Resistant individuals were found at 16 and 32 metres from the transgenic pollen donors, but the frequency of an outcrossing event dropped to 10-5.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023974
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  • 92
    Electronic Resource
    Electronic Resource
    Genetic engineering of Indica rice in support of sustained production of affordable and high quality food in developing countries (1955)
    Springer
    Euphytica 85 (1955), S. 441-449 
    Details
    ISSN: 1573-5060
    Keywords: Oryza sativa ; Indica-type rice ; genetic engineering ; vitamin A endosperm ; insect resistance ; virus resistance ; fungus resistance ; essential amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Indica-type rice provides the staple food for two billion people in Third World countries. Several problems involved in the stable and sustained production of high quality food cannot be solved by traditional breeding. Methods have been established for gene transfer to Indica rice breeding lines to study possible contributions from genetic engineering. Experiments are in progress on the development of transgenic resistance towards Yellow Stem Borer, resistance towards Rice Tungro Virus, accumulation of provitamin A in the endosperm, increase of essential amino acids in the endosperm such as lysine, cysteine and methionine and resistance towards fungal pests such as Rice Blast and Sheath Blight. Transgenic clones from Indica rice breeding lines have been recovered from several of the approaches mentioned, some of which have been regenerated to plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023978
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  • 93
    Electronic Resource
    Electronic Resource
    Potato germplasm enhancement for resistance to biotic stresses at CIP. Conventional and biotechnology-assisted approaches using a wide range of Solanum species (1955)
    Springer
    Euphytica 85 (1955), S. 457-464 
    Details
    ISSN: 1573-5060
    Keywords: genetic engineering ; introgression ; molecular markers ; potatoes ; resistances ; Solanum ; technology mansfer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Potato genetic improvement has been facilitated using new knowledge of potato reproductive biology and new techniques. Many wild diploid species as well as landrace cultivars have been used in breeding at the diploid level, a strategy which is supported by 1) 2n gametes and 2) haploids from tetraploid cultivars. Different categories of wild species which have been under-utilized are now being exploited further in more systematic enhancement programmes using semi-conventional and biotechnological methods. Molecular maps of the potato genome are used actively to achieve marker-assisted introgression and improved selection among the germplasm collections to facilitate the use of valuable wild genetic resources. As an alternative method to incorporate a high level of fesistance, genetic engineering has been employed to facilitate the initial breeding process using various gene constructs for controlling major biotic stresses in the world.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023980
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  • 94
    Electronic Resource
    Electronic Resource
    Genetic manipulation in plant breeding — prospects and limitations (1955)
    Springer
    Euphytica 85 (1955), S. 1-12 
    Details
    ISSN: 1573-5060
    Keywords: genetic engineering ; gene targets ; mapping ; markers ; transformation ; QTLs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023925
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  • 95
    Electronic Resource
    Electronic Resource
    The application of chemical mutagenesis and biotechnology to the modification of linseed (Linum usitatissimum L.) (1955)
    Springer
    Euphytica 85 (1955), S. 317-321 
    Details
    ISSN: 1573-5060
    Keywords: Linum usitatissimum ; linseed ; mutation breeding ; somaclonal variation ; fatty acids ; genetic engineering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In the early 1980s the phenomenon of somaclonal variation induced by cell culture was exploited to produce genetic variation in linseed. The linseed variety Andro, derived from the widely grown Canadian variety McGregor, was selected in saline culture and was released for production in Canada. ‘Andro’ possesses traits very different from its parent, such as increased seedling vigour and tolerance to heat stress. Additional stable somaclonal variation in characters such as yield, days to maturity, seed weight and oil content were subsequently induced in ‘McGregor’. However, despite extensive screening of the somaclonal variants, no significant variation in the fatty acid profile was found. Chemical mutagenesis using ethyl methanesulphonate was, however, succesful in modifying the fatty acid profile of McGregor. Initial screening of M2 seed by the thiobarbituric acid colourimetric procedure was followed by gas chromatography to select half-seeds with atypical fatty acid profiles. Two independent, partially dominant genes were identified that were responsible for reducing the linolenic acid (18 : 3) from 50% to 2% while increasing linoleic acid (18 : 2) to 70%. A single, partially dominant gene, inherited independently of the linolenic acid genes, increased palmitic acid (16 : 0) from 7% to 30% and palmitoleic acid (16 : 1) from trace amounts to 4%. Agrobacterium-mediated transformation of linseed has also been successful. Herbicide tolerance genes for glyphosate, sulfonylurea and phosphinothricin have been incorporated into Canadian varieties. Commercially useful levels of tolerance to sulfonylurea herbicides have been achieved with no adverse agronomic affect. It is expected that a transgenic variety containing this resistance will be registered for commercial production in Canada in 1994. Standard breeding techniques, the application of antisense technology and the overexpression of fatty acid synthesis genes are being used to further modify the fatty acid profile of linseed, as well as for the transfer of abiotic stress-related genes identified in bromegrass.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023961
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  • 96
    Electronic Resource
    Electronic Resource
    An assessment of morphogenic and transformation efficiency in a range of varieties of potato (Solanum tuberosum L.) (1955)
    Springer
    Euphytica 85 (1955), S. 101-108 
    Details
    ISSN: 1573-5060
    Keywords: Agrobacterium ; plant regeneration ; potato ; Solanum tuberosum ; tissue culture ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary To provide a truly genotype-independent transformation system, it is necessary to be able to transform a wide range of potato genotypes. The ability to regenerate shoots in vitro was determined for 34 potato varieties using tuber disc explants. Following a culture regime used extensively in previous studies with the variety Desiree, half of the varieties could be regenerated from tuber discs and half could not. From a sample of varieties that could be regenerated from tuber discs, all but one variety gave transgenic plants. Twelve varieties were evaluated for the capacity to regenerate shoots from leaf and internode explants excised from in vitro grown plants. All of the varieties tested regenerated adventitious shoots. Leaf and internode explants from 5 varieties were subsequently used for transformation, and transgenic plants were produced from two potato varieties that did not give transgenic plants from tuber disc explants. Some varieties could not be transformed by either method, and will require modification of the in vitro regeneration and transformation system to be successful.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023936
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  • 97
    Electronic Resource
    Electronic Resource
    Some methodological aspects of apple transformation by Agrobacterium (1955)
    Springer
    Euphytica 85 (1955), S. 131-134 
    Details
    ISSN: 1573-5060
    Keywords: apple ; transformation ; Agrobacterium ; preculture ; azacytidine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Leaf explants of apple cvs Gala and Golden Delicious were infected with the Agrobacterium tumefaciens strain AGL0(pMOG410). The effects of a 2 d preculture of the explants before infection and the addition of 5-azacytidine to the selection medium were studied. The percentages of GUS-positive explants after 5 w did not significantly alter due to these treatments. One of the ‘Gala’ shoots, which was removed from a leaf explant cultured for 8 w on selection medium, proved to be GUS-positive and will be analyzed further. In general, however, it should be concluded that regeneration of transgenic shoots directly from leaf tissue was not very effective.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023941
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