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  • 2010-2014
  • 1995-1999  (7)
  • 1955-1959
  • 1880-1889
  • 1999  (7)
  • particle bombardment
Material
Years
  • 2010-2014
  • 1995-1999  (7)
  • 1955-1959
  • 1880-1889
Year
  • 1
    ISSN: 1573-9368
    Keywords: low molecular weight glutenin promoter ; particle bombardment ; transgene expression ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transgenic wheat plants from specific cultivars can now be routinely engineered in many laboratories. However, our understanding of the factors controlling transgene expression and stability in wheat compared to other cereals is rather limited. Only a few promoters have been tested in transgenic wheat, and relatively little is known of their relative activities and expression parameters. In the present study, the spatial and temporal properties of one heterologous constitutive promoter and one seed‐specific wheat promoter were investigated. We generated constructs with the reporter gene gusA (β‐glucuronidase) driven by: (a) the constitutive maize ubiquitin‐1 (ubi‐1) promoter, and (b) two different‐sized fragments of the seed‐specific low molecular weight glutenin (LMWG1D1) promoter from wheat. The activities of all three promoter constructs were comparable in endosperm tissue. A detailed analysis of spatial and temporal properties of the promoters is described. Heat shock treatment of transgenic plants carrying the ubi‐1: gusA construct resulted in a significant elevation in the levels of GUS activity. The inheritance of transgene expression levels and stability was evaluated over four generations, as a function of transgene integration patterns and copy number.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1572-9788
    Keywords: Basmati 370 and M7 varieties ; δ-endotoxins (Cry1Ac and Cry2A) ; particle bombardment ; snowdrop lectin (GNA) ; transgenic rice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We cotransformed indica rice (Oryza sativa L. cvs. Basmati 370 and M7) with three plasmids, carrying a total of four genes, by particle bombardment. The Bacillus thuringiensis (Bt) δ-endotoxin genes cry1Ac and cry2A were carried on separate vectors, while the gna (snowdrop lectin) and hpt (hygromycin phosphotransferase) genes were linked on the same, cointegrate vector. We evaluated the molecular and expression profiles of 29 independently derived transgenic lines over two generations. The gna and hpt genes cointegrated with a frequency of 100% as expected. Furthermore, 60% of the transgenic plants carried all four genes. Southern blot analysis showed that transgene copy number ranged from 1 to 15. We used western blots to determine protein expression levels in R0 and R1 plants. We observed wide variation in the expression levels of the nonselected transgenes among independently-derived lines, but expression levels within lines derived from the same clone were similar. Consistent with previous reports, we observed no correlation between transgene copy number and the level or stability of protein expression. We show that the introduction of multiple agronomically valuable genes into the rice genome by cotransformation is a practical strategy for engineering elite rice varieties.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-5028
    Keywords: enhancer ; flavonoids ; particle bombardment ; pericarp ; promoter ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The maize P-rr gene conditions floral-specific flavonoid pigmentation, especially in the kernel pericarp and cob. We analyzed the P-rr promoter by transient expression assays, in which segments of the P-rr promoter were fused to the GUS reporter gene and introduced into maize cells by particle bombardment. A basal P-rr promoter fragment (−235 to +326) gave low, but significant, levels of GUS reporter gene expression. Interestingly, two widely spaced segments containing enhancer-like activity were found. When tested individually, both the proximal (−1252 to −236) and distal (−6110 to −4842) segments boosted expression of the basal P-rr promoter::GUS construct about five-fold. A 1.6 kb segment of the P-rr promoter (−1252 to +326) containing the proximal enhancer and the 5′-untranslated leader driving the GUS reporter gene showed preferential expression in BMS and embryogenic suspension cell cultures vs. endosperm-derived suspension cell cultures. These results demonstrate the application of transient assay techniques for the identification of regulatory elements responsible for floral-specific regulation of the complex P-rr gene promoter in maize.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-5028
    Keywords: cellulase ; heterologous expression ; Hordeum vulgare L. ; particle bombardment ; thermotolerant endo-1.4-β-glucanase ; transgenic barley
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The malting quality of two barley cultivars, Kymppi and Golden Promise, was modified to better meet the requirements of the brewing process. The egl1 gene, coding for fungal thermotolerant endo-1,4-β-glucanase (EGI, cellulase), was transferred to the cultivars using particle bombardment, and transgenic plants were regenerated on bialaphos selection. Integration of the egl1 gene was confirmed by Southern blot hybridization. The transgenic seeds were screened for the expression of the heterologous EGI. Under the high-pI α-amylase promoter, the egl1 gene was expressed during germination. The heterologous enzyme was thermotolerant at 65 °C for 2 h, thus being suitable for mashing conditions. The amount of heterologous EGI produced by the seeds (ca. 0.025% of soluble seed protein), has been shown to be sufficient to reduce wort viscosity by decreasing the soluble β-glucan content. A decrease in the soluble β-glucan content in the wort improves the filtration rate of beer.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-5060
    Keywords: gus expressing cells ; histological analysis ; japonica and indica rice ; particle bombardment ; primary callus ; regeneration capacity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The microprojectile bombardment procedure has allowed the stable transformation of indica and japonica rice varieties, although at different frequencies of transformation depending mainly on their regeneration capacity and on the specific parameters of the transformation protocol. A study of the process of regeneration to whole plants from primary calli derived from mature indica and japonica rice seeds, via embryogenesis, has shown that somatic embryos are produced by division and differentiation of the external cell layers of callus tissues. Adjusting the bombardment conditions to optimize gene delivery to those regenerable cells, we have evaluated the influence of parameters such as the target distance, particle penetration and the effect of osmotic treatment on the regeneration capacity of bombarded cells.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-6776
    Keywords: β-glucuronidase ; Catharanthus roseus ; genetic transformation ; green fluorescent protein ; particle bombardment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract In vitro propagation of Catharanthus roseus was achieved using nodal explants. Bud induction was best on medium containing 1.0 mg benzyl aminopurine l−1. Hardening of rooted shoots to soil was very successful with 98% survival. Genetically transformed C. roseus plantlets were obtained after bombardment of nodal explants, which were then micropropagated, with DNA coated particles with green fluorescent protein (GFP) or β-glucuronidase (GUS) reporter genes. Histological studies showed that the gene insertion method proved effective with many cells and different tissues displaying the reporter gene signals, showing that gene expressions were rather stable.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-9368
    Keywords: Antirrhinum ; Arabidopsis ; green fluorescent protein (GFP) ; in vitro ; microspores ; particle bombardment ; tobacco
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The transient expression of three mutant forms of green fluorescent protein (GFP) genes, GFP4, GFP5ER, and GFP4S65C, under several constitutive and pollen‐specific promoters throughout pollen development in Nicotianatabacum, thaliana and Antirrhinummajus is described. Immature pollen of tobacco, Arabidopsis and snapdragon, isolated at different developmental stages, were bombarded with plasmids containing the GFP and cultured in vitro for several days until maturity. The expression of GFP was monitored every day during in vitro maturation, germination and pollination, as well as after in situ pollination. The expression pattern of each construct was compared in parallel experiments to that of ß‐glucuronidase (GUS) constructs expressed by the same promoters. The results show that the expression level of all three GFP mutant forms was dependent on the strength of the promoter used. The strongest promoter was the DC3 promoter, and no notable differences in the intensity and brightness of all three versions of GFP were observed. GFP‐expressing pollen from tobacco and snapdragon developed in vitro for several days until maturity and germinated in vitro as well as on the surface of stigmata, strongly suggesting that all three GFPs are not toxic for the development of functional pollen. Furthermore, stably transformed tobacco plants expressing GFP under the control of the strong pollen‐expressed DC3 and LAT52 promoters were not impaired in reproductive function, confirming that GFP can be used as a non‐destructive marker for plant reproductive biology and development.
    Type of Medium: Electronic Resource
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