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  • 1
    ISSN: 1432-203X
    Keywords: Key words Forage and turf grasses ; Italian ryegrass ; Lolium multiflorum ; Microprojectile bombardment ; Transgenic plants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transgenic forage-type Italian ryegrass (Lolium multiflorum Lam.) plants have been obtained by microprojectile bombardment of embryogenic suspension cells using a chimeric hygromycin phosphotransferase (hph) gene construct driven by rice Act1 5′ regulatory sequences. Parameters for the bombardment of embryogenic suspension cultures with the particle inflow gun were partially optimized using transient expression assays of a chimeric β-glucuronidase (gusA) gene driven by the maize Ubi1 promoter. Stably transformed clones were recovered with a selection scheme using hygromycin in liquid medium followed by a plate selection. Plants were regenerated from 33% of the hygromycin-resistant calli. The transgenic nature of the regenerated plants was demonstrated by Southern hybridization analysis. Expression of the transgene in transformed adult Italian ryegrass plants was confirmed by northern analysis and a hygromycin phosphotransferase enzyme assay.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2242
    Keywords: Asymmetric somatic hybrids ; forage grasses: fescues and ryegrasses ; Plastome-genome interaction ; Festuca arundinacea ; Lolium multiflorum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Intergeneric asymmetric somatic hybrids have been obtained by the fusion of metabolically inactivated protoplasts from embryogenic suspension cultures ofFestuca arundinacea (recipient) and protoplasts from a non-morphogenic cell suspension ofLolium multiflorum (donor) irradiated with 10, 25, 50, 100, 250 and 500 Gy of X-rays. Regenerating calli led to the recovery of genotypically and phenotypically different asymmetric somatic hybridFestulolium plants. The genome composition of the asymmetric somatic hybrid clones was characterized by quantitative dot-blot hybridizations using dispersed repetitive DNA sequences specific to tall fescue and Italian ryegrass. Data from dot-blot hybridizations using two cloned Italian ryegrass-specific sequences as probes showed that irradiation favoured a unidirectional elimination of most or part of the donor chromosomes in asymmetric somatic hybrid clones obtained from fusion experiments using donor protoplasts irradiated at doses ≤ 250 Gy. Irradiation of cells of the donor parent with 500 Gy prior to protoplast fusion produced highly asymmetric nuclear hybrids with over 80% elimination of the donor genome as well as clones showing a complete loss of donor chromosomes. Further information on the degree of asymmetry in regenerated hybrid plants was obtained from chromosomal analysis including in situ hybridizations withL. multiflorum-specific repetitive sequences. A Southern blot hybridization analysis using one chloroplast and six mitochondrial-specific probes revealed preferentially recipient-type organelles in asymmetric somatic hybrid clones obtained from fusion experiments with donor protoplasts irradiated with doses higher than 100 Gy. It is concluded that the irradiation of donor cells before fusion at different doses can be used for producing both nuclear hybrids with limited donor DNA elimination or highly asymmetric nuclear hybrid plants in an intergeneric graminaceous combination. For a wide range of radiation doses tested (25–250Gy), the degree of the species-specific genome elimination from the irradiated partner seems not to be dose dependent. A bias towards recipient-type organelles was apparent when extensive donor nuclear genome elimination occurred.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-5060
    Keywords: intergeneric somatic hybrids ; forage grasses ; fescue ; Festuca arundinacea ; F. rubra ; ryegrasses ; Lolium multiflorum ; L. perenne ; Alopecurus pratensis ; species-specific repetitive DNA sequences
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Intergeneric symmetric and asymmetric somatic hybrids have been obtained by fusion of metabolically inactivated protoplasts from embryogenic suspension cultures of tall fescue (Festuca arundinacea Schreb.) and unirradiated or 10–500 Gy-irradiated protoplasts from non-morphogenic cell suspensions of Italian ryegrass (Lolium multiflorum Lam.). Genotypically and phenotypically different somatic hybrid Festulolium mature flowering plants were regenerated. Species-specific sequences from F. arundinacea and L. multiflorum being dispersed and evenly-represented in the corresponding genomes were isolated and used for the molecular characterization of the nuclear make-up of the intergeneric, somatic Festulolium plants recovered. The irradiation of Italian ryegrass protoplasts with ≤250 Gy X-rays prior to fusogenic treatment favoured the unidirectional elimination of most or part of the donor chromosomes. Irradiation of L. multiflorum protoplasts with 500 Gy produced highly asymmetric (over 80% donor genome elimination) nuclear hybrids and clones showing a complete loss of donor chromosomes. The RFLP analysis of the organellar composition in symmetric and asymmetric tall fescue (+) Italian ryegrass regenerants confirmed their somatic hybrid character and revealed a bias towards recipient-type organelles when extensive donor nuclear genome elimination had occurred. Approaches aimed at improving persistence of ryegrasses based on asymmetric somatic hybridization with largely sexually-incompatible grass species (F. rubra and Alopecurus pratensis), and at transferring the cytoplasmic male sterility trait by intra- and inter-specific hybridization in L. multiflorum and L. perenne, have been undertaken.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 30 (1992), S. 299-304 
    ISSN: 0887-624X
    Keywords: polyformal ; polycarbonate ; copoly(carbonate formal) ; phase-transfer catalyst ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A linear, high molecular weight polyformal is readily synthesized by direct transformation of commercially available polycarbonate. The reaction is best carried out in dibromomethane with 8.0 equiv. of potassium hydroxide pellets in the presence of a phase-transfer catalyst at 90-95°C. A random copoly(carbonate formal) can also be obtained simply by reducing the amount of potassium hydroxide used in the reaction. The molecular weight of the resulting polymer is governed by the starting polycarbonate.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 29 (1991), S. 1045-1052 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of a novel bisphenol, 9,9-bis(3,5-diphenyl-4-hydroxyphenyl)fluorene, in high yield by the transalkylation of 9,9-bis(4-hydroxyphenyl)fluorene is described. Three poly(arylene ether)s based on this hindered phenol were prepared with molecular weights (Mn) ranging from 34 800 to 51 300 and inherent viscosities ranging from 0.27 to 0.43 dL/g. The polymers have Tg's of 236-262°C and did not lose weight below 350°C, with 10% weight loss recorded above 550°C. They are readily soluble in chlorinated solvents such as methylene chloride, chloroform, and 1,2-dichloroethane at room temperature. Attempts to synthesize an analogous monomer, bis (3,5-diphenyl-4-hydroxyphenyl)diphenylmethane, are described.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 36 (1998), S. 425-431 
    ISSN: 0887-6266
    Keywords: poly(arylene ether ketone) ; gas permeability ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In this work we present the results from studies on novel poly(arylene ether ketone)s, including gas permeability, wide-angle x-ray diffraction (WAXD), and dynamic mechanical analysis (DMA). Poly(arylene ether ketone)s containing 2,2′- and 3,3′-dibenzoylbiphenyl (DBBP) moieties were characterized to study the effect of biphenyl substitution on gas transport properties. Gas permeabilities of naphthalene-containing poly(arylene ether ketone)s were also measured. Higher permeabilities were observed for polymers prepared with 6F-BPA, compared to 9,9-bis(4-hydroxyphenyl)fluorene (HPF). The naphthalene-containing polymers exhibited higher permeabilities than the DBBP polymers, except for a polymer having the 2,2′-DBBP and tetramethylbiphenyl moieties. Based on our work, and results reported in the literature, the 3,3′-DBBP polymers showed the lowest permeabilities for DBBP-containing poly-(arylene ether ketone)s. The low permeabilities are due to more efficiently packed chains brought on by greater flexibility of the backbone, compared to the other polymers studied. DMA studies confirmed the higher barriers to rotation which are believed to be responsible for 2,2′-DBBP polymers having similar selectivities compared to 3,3′-DBBP polymers. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 425-431, 1998
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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