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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Potato research 29 (1986), S. 367-379 
    ISSN: 1871-4528
    Keywords: hairy-root ; Ri-plasmid ; T-DNA ; potato cultivars ; in vitro culture ; field experiments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Zusammenfassung Infektion verwundeter Stengel in vitrogewachsenen Kartoffelsorten hatte lokale, proliferierende Wurzelbildung (haarige Wurzeln; Abb. 2A) zur Folge. Diese Wurzelzellen enthielten neu eingebrachte DNA, die nicht in normalen Kartoffeln entdeckt werden konnte, sondern aufA. rhizogenes zurückzuführen ist (Mechanismen vgl. Abb. 1). Einzelne umgebildete Wurzeln der Sorten Majestic, Record und Maris Bard wurden zu ganzen Pflanzen regeneriert (Abb. 2B, C). Die meisten der transformierten Pflanzen waren euploid (2n=4x=48; Abb. 2D). Der Ausdruck der eingebrachten Gene ergab stabile Veränderungen bei Pflanzenentwicklung und Knollengestalt (Abb. 2E), welche auch unter Feldbedingungen erhalten blieben (Abb. 2F, 3 und Tabelle 1). Daraus wurde geschlossen, dass (1) vermutlich jede kommerzielle Kartoffelsorte unter entsprechenden BedingungenAgrobacterium-vermittelter genetischer Veränderung zugänglich ist; (2) die vonA. rhizogenes abstammenden Gene konventionelle Modellgene zum Studium des Ausdrucks von Struktur, Kontrolle und Stabilität transferierter Gene sind; und (3) vonA. rhizogenes abstammende Gene von potentiellem Nutzen zum Studium des Einflusses spezifischer genetischer Faktoren auf komplexer biologischer Prozesse wie Knollenentwicklung und Knollenbildung sind. Vielleicht können Gene, wie die vonA. rhizogenes abgeleiteten T-DNA-Gene, welche kontrollierenden Einfluss auf die Pflanzenentwicklung und Knollenbildung zeigen, zur Hervorbringung von nützlichen Änderungen, die für bestimmte Kartoffellinien von Nutzen sind, verwendet werden.
    Abstract: Résumé L'infection de tiges blessées de variétés de pommes de terre cultivées in vitro avecAgrobacterium rhizogenes a causé une prolifération localisée de racines (racines chevelues, Fig. 2A). Les cellules de ces racines contenaient du DNA nouvellement introduit, non décelable chez la pomme de terre non infectée, provenant deA. rhizogenes (pour le mécanisme voir Fig. 1). De simples racines modifiées génétiquement, issues des variétés Majestic, Record et Maris Bard, régénéraient des plantes entières (Fig. 2B-C). La plupart des plantes régénérées étaient euploïdes 2n=4x=48 (Fig. 2D): les gênes introduits s'exprimaient par des modifications stables au niveau du développement de la plante et de la forme des tubercules (Fig. 2E), même dans les conditions du champ (Fig. 2F, 3 et tableau 1). On en concluait que (i) probablement n'importe quelle variété commerciale cultivée dans des conditions appropriées peut être soumise à des manipulations avecAgrobacterium comme médiateur; (ii) les gênes provenant deA. rhizogenes sont des modèles génétiques possibles pour étudier les questions concernant la structure, le contrôle et la stabilité de l'expression des gênes transférés. En outre, (iii) les gênes provenant d'A. rhizogenes constituent un matériel potentiel pour étudier l'influence des facteurs génétiques spécifiques sur des processus biologiques complexes tels que la croissance et la tubérisation de la pomme de terre. Peut être que des gênes semblables aux gênes T-DNA deA. rhizogenes ont une influence sur le développement de la plante; peut être aussi que leur introduction occasionnerait des modifications bénéfiques, en particulier pour les lignées de pomme de terre.
    Notes: Summary Infection withAgrobacterium rhizogenes of wounded stems of potato cultivars grown in vitro caused localized prolific root formation (hairy-roots). The cells of these roots contained newly introduced DNA, not detected in normal potato, that was derived fromA. rhizogenes. Single transformed roots from the cultivars Majestic, Record and Maris Bard were regenerated into whole plants. Expression of the introduced genes caused stable alterations in plant development and tuber shape, which were retained under field conditions. The following conclusions were reached. (i) Probably any commercial potato cultivar, cultured under appropriate conditions, is amenable toA. rhizogenes-mediated genetic manipulation. (ii) TheA. rhizogenes-derived genes are convenient model genes for studying questions on structure and expression of transferred genes. (iii) A. rhizogenes-derived genes are of potential use to study the influence of specific genetic factors on complex biological processes such as potato development and tuberization.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology 2 (1983), S. 317-320 
    ISSN: 1573-5028
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Large amounts of pathogenesis-related (PR) proteins were found inNicotiana tabacum crown gall tissue, following transformation of normal tobacco cells withAgrobacterium tumefaciens. In contrast, PR proteins were not detected in leaves of grafted plants that had been recovered from crown gall tissue even though these plants were still transformed as shown by their inability to form roots and ability to produce octopine. No difference was observed in susceptibility to virus infection between untransformed and transformed plants grafted onto identical rootstocks. The results are discussed in relation to physiological factors controlling PR protein induction and virus resistance.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Flow, turbulence and combustion 30 (1975), S. 381-399 
    ISSN: 1573-1987
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Using Spalding's model of turbulence in a turbulent shear flow, we have calculated the root-mean-square value of the concentration fluctuations inside a turbulent jet. Although we used the same equations and the same solution technique as Spalding, we have not been able to find precisely his numerical results derived for a jet issuing into a fluid at rest with the same density as the jet. The differences between our numerical results, Spalding's numerical results and the experimental data of Becker, Hottel and Williams are fairly small only if the initial values of the turbulence energy and the mixing length inside the jet and the turbulence in the ambient fluid are taken into account in the model. For a turbulent jet issuing into a turbulently flowing surrounding stream of different density, we found that the relative concentration fluctuations can increase considerably. This brings out the importance of taking into account property variables in analysing turbulent mixing processes.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Flow, turbulence and combustion 36 (1981), S. 339-356 
    ISSN: 1573-1987
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Some years ago we developed a theoretical model for the calculation of the rise of a stack plume in the atmosphere. Recently we have extended this model in such a way that the ground level concentration of gases emitted by a stack can also be calculated. The cross-section of the plume, which was originally assumed to be a circle, is now assumed to be an ellipse. The height-to-width ratio of the ellipse is chosen in accordance with full-scale data. The entrainment of air into the plume due to atmospheric turbulence can now be calculated not only for neutral atmospheric conditions, but also for stable and unstable conditions. Predictions of the ground level concentration made with this model have been compared with predictions made with the often used virtual point source model. For neutral and unstable atmospheric conditions the agreement is rather good. For stable conditions the differences can be rather large. The sensitivity of the ground level concentration with respect to the atmospheric stability condition, the stack height, the plume exit momentum flux and the plume exit buoyancy flux has also been investigated with the aid of the model. The influence of the plume exit momentum flux is negligible; however, the influence of the other parameters can be large.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology 5 (1985), S. 205-212 
    ISSN: 1573-5028
    Keywords: Agrobacterium tumefaciens ; auxin ; cytokinin ; potato ; tuberisation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Potato Line Mb1501B is a derivative of the cultivar Maris Bard (Solanum tuberosum), transformed with T-DNA from A. tumefaciens strain LBA1501. In culture it grew as frequently branching stunted shoots with a basal callus, lacking roots. These shoots did not form tubers. When grafted, Mb1501B shoots gradually became morphologically more normal and aerial tubers formed readily. Cultured Mb1501B shoots contained 100–200-fold higher concentrations of the biologically-active cytokinins zeatin, zeatin riboside and their corresponding side-chain o-glucosides than untransformed Maris Bard shoots. Cultured Mb1501B shoots contained approximately a 3-fold lower concentration of indole acetic acid (IAA). In grafted Mb1501B plants a 3–10-fold higher concentration of the active cytokinins was found compared with untransformed plants and no difference in IAA concentration.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology 5 (1985), S. 213-222 
    ISSN: 1573-5028
    Keywords: Agrobacterium tumefaciens ; gene expression ; potato ; T-DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In potato line Mb1501B one or possibly two normal size Ti TL-DNA copies per tetraploid genome were detected by Southern blot analysis, but no TR-DNA. The TL-DNA probably contained the entire transposon Tn1831 inserted at the T-DNA auxin gene for transcript 2. Northern blot analyses of the steady-state RNA in different Mb1501B tissues isolated from (i) shoots cultured in vitro (ii) grafted plants and (iii) tubers, showed that that TL-DNA transcripts 3, 4, 6a and 7 were expressed most abundantly in the cultured shoots. They formed approximately 0.0023 to 0.0007% of the total poly(A) RNA. Transcripts 1, 5 and 6b were not detected in any of the tissues analysed. This indicated even lower levels of expression (below approximately 0.0001% of the total poly(A) RNA or, making certain assumptions, an abundance of less than one T-DNA derived RNA molecule per cell). As expected, transcript 2 was not detected in any of the Mb1501B tissues. The abundance of the transcripts was reduced in grafted plants and tubers compared with cultured shoots with the greatest decrease (5×) for transcripts 4, 6a and 7. Transcript 4, the one most responsible for the changed growth and development of Mb 1501 B, formed approximately 0.0003% of the poly(A) RNA from both grafted plants and tubers.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology 6 (1986), S. 213-220 
    ISSN: 1573-5028
    Keywords: Crown gall ; cytokinins ; in vitro translation ; poly(A) RNA ; potato ; T-DNa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two dimensional gel electrophoresis was used to examine differences in steady state total poly(A) RNA from untransformed potato (Solanum tuberosum cv. Maris Bard) and potato transformed with shoot-inducing TL-DNA from A. tumefaciens. RNA was compared from phenotypically very distinct in vitro cultured shoots, more similar grafted plants and tubers. In each case between 200–400 translation products were identified representing the more abundant poly(A) mRNA's. In general, poly(A) RNA from the transformed tissues gave more high molecular weight products. This increase was most evident in poly(A) RNA from shoot cultures. Depending on the tissue examined, 1–5% of the translation products with a molecular weight 〈43 KD were observed to increase or decrease in abundance. The influence of T-DNA on cellular gene expression in the different transformed potato tissues is discussed in relation to previously determined changes in T-DNA gene expression (particularly of the T-DNA cytokinin gene) and the corresponding changes in endogenous hormone concentrations. It is concluded that some of the specific changes in low molecular weight products are either directly caused by the increased cytokinin levels or are indirectly involved in maintaining the transformed phenotype. re]19850530 rv]19851206 ac]19851210
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  • 8
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
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  • 9
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Flow, turbulence and combustion 26 (1972), S. 147-158 
    ISSN: 1573-1987
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The hydrodynamic stability of core-annular flow of two ideal liquids through a pipe is investigated. If the thickness of the annular layer is much smaller than the radius of the pipe, the pipe wall has a strong reducing effect on the growth velocity of possible Rayleigh-Taylor and Kelvin-Helmholtz instabilities at the interface between the two liquids.
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