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  • 1
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 52 (1988), S. 584-586 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Superconducting thin films of Y-Ba-Cu-O near the 1:2:3 stoichiometry were produced by simultaneous (coevaporation) and sequential (multilayer) evaporation in the same evaporator. The best film obtained on yttria-stabilized zirconia (YSZ) had a superconducting onset temperature of 104 K, a midpoint Tc of 92 K, and zero resistance at T≤74 K. Stoichiometry was deduced by inductively coupled plasma emission spectroscopy, and elemental depth profiles were obtained by x-ray photoelectron spectroscopy. Film stoichiometry changes only near the film/substrate boundary for films on YSZ. Films on Si/SiO2 were not superconducting; depth profiling shows severe changes of film composition with depth. A major theme of this work is process reproducibility, which was found to be poor for coevaporation but improved considerably for sequential evaporation.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 52 (1988), S. 2068-2070 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Thin films of the high-temperature superconductor Y-Ba-Cu-O with zero-resistance transition temperatures up to 83 K have been recently reported by using a zirconia buffer layer on the primary materials of interest for electronics, Si and SiO2. In this letter, various characteristics of these films are discussed. Microstructural analysis using transmission electron microscopy shows the complex morphology of the unoriented polycrystalline films. Elemental depth profiling by x-ray photoelectron spectroscopy shows the effectiveness of the zirconia buffer layer in preventing interdiffusion; fluorine is found throughout the film at an abundance of 4 at. % The critical current density was measured as a function of temperature; its value is 5 kA cm−2 at 4.2 K.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Langmuir 2 (1986), S. 37-42 
    ISSN: 1520-5827
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 70 (1985), S. 440-446 
    ISSN: 1432-2242
    Keywords: Agrobacterium rhizogenes ; Potato ; Somaclonal variation ; Genetic manipulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Forty-two potato plants were regenerated from a hairy-root line obtained after infection of a shoot of Solanum tuberosum cv ‘Desiree’ with Agrobacterium rhizogenes strain LBA 9402 (pRil855). Transformed plants were uniform and had a distinct phenotype and development compared with untransformed controls. Their growth was vigorous, especially early in their development, their roots were abundant and showed reduced geotropism, their leaves were slightly crinkled and glossy and they produced longer tubers with more frequent, prominent eyes. Cytological examination showed that ten of the forty-two transformed plants had either 47 or 49 chromosomes instead of the normal 48. In two of these aneuploids structural changes were observed.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 71 (1985), S. 325-329 
    ISSN: 1432-2242
    Keywords: A. tumefaciens ; A. rhizogenes ; Brassica napus ; Plant development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The response of oilseed rape cultivars to infection with Agrobacterium tumefaciens and A. rhizogenes and the possibility of regenerating genetically transformed oilseed rape plants were examined. The frequency at which Agrobacterium induced galls or hairy-roots on in vitro cultured plants ranged from 10% to 70%, depending on the cultivar. From galls induced by the tumorigenic strain T37, known to be strongly shoot inducing on tobacco, roots developed frequently. Occasionally, shoots formed and some of these produced tumour cell specific nopaline. Attempts to grow the transformed shoots into plants have so far been unsuccessful. Whole plants transformed with Ri-T-DNA, however, were regenerated. These had crinkled leaves and abundant, frequently branching roots that showed reduced geotropism, similar to previously isolated Ri T-DNA transformed tobacco and potato plants. The transformed oilseed rape plants flowered, but failed to form seeds.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 73 (1987), S. 744-750 
    ISSN: 1432-2242
    Keywords: Genetic manipulation ; Neomycin phosphotransferase ; Mixed infection ; Somaclonal variation ; Solanum tuberosum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Derivatives of potato (Solanum tuberosum cv.'s ‘Maris Bard’ and ‘Desiree’) transformed with disarmed T-DNA from genetically engineered Agrobacterium tumefaciens strains were isolated. The transformed plants were recovered from shoot-forming tumours induced by infection of wounds with mixedcultures of shoot-inducing A. tumefaciens strains T37 and either Agrobacterium strain LBA1834(pRAL1834), (Hille et al. 1983) or LBA4404(pBIN6; pRAL4404), (Bevan 1984). Two small-scale feasibility experiments gave at least four ‘Maris Bard’ plants transformed with pRAL1834 T-DNA and two ‘Desiree’ plants with pBIN6 T-DNA. The transformed ‘Maris Bard’ plants were morphologically abnormal and highly aneuploid. This was probably an unfortunate side-effect of a tissue culture-step introduced to promote the efficiency of shoot regeneration. The transformed ‘Desiree’ plants, in contrast, were isolated without promoting additional shoot-growth. They were morphologically normal, contained 47 and the euploid 48 chromosomes per cell respectively and had improved growth on media containing kanamycin.
    Type of Medium: Electronic Resource
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  • 7
    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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  • 8
    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.
    Type of Medium: Electronic Resource
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  • 9
    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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