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  • tissue culture
  • transformation
  • β-glucuronidase
  • Springer  (126)
  • American Meteorological Society
  • Cambridge University Press
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  • Springer  (126)
  • American Meteorological Society
  • Cambridge University Press
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  • 1995-1999  (50)
  • 1990-1994  (61)
  • 1955-1959  (15)
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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 19 (1991), S. 453-459 
    ISSN: 1432-0983
    Schlagwort(e): β-glucuronidase ; Transformation ; Fungi ; Late blight
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Vectors containing fusions between the reporter gene β-glucuronidase (GUS) and transcriptional regulatory signals from the ham34 and hsp70 genes of the oomycete pathogen, Bremia lactucae, were introduced into protoplasts of the related fungus Phytophthora infestans. Transient expression of the GUS gene was detected when DNA was introduced into protoplasts of P. infestans by treatments with polyethylene glycol and CaCl2 with cationic liposomes, or by electroporation. After optimization of each procedure, using the transient expression assays, cationic liposomes were identified as the superior method for DNA uptake. Vectors containing the 5′hsp70 sequences and 3′ham34 sequences resulted in the maximum level of GUS activity. The identification of functional vectors for transformation, and of optimal methods for introducing DNA, should assist in achieving stable transformation of P. infestans and other oomycete the fungi.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Methods in cell science 13 (1991), S. 149-161 
    ISSN: 1573-0603
    Schlagwort(e): tissue culture ; sharks ; epithelia ; chloride transport ; kidney tubules ; cell regulation ; cystic fibrosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Methods are described for establishing primary monolayer cultures from chloride-secreting epithelial cells of the dogfish shark (Squalus acanthias) rectal gland (SRG). After stimulation, cultures display exceptionally high rates (150 to 250μA/cm2) of transepithelial chloride secretion. Hormones and neurotransmitters which increase cytoplasmic cyclic AMP, cyclic GMP, calcium or phospholipid-derived second messengers are potent secretagogues. Cultures can be analyzed using a variety of morphologic, biochemical, and electrophysiologic methods. These characteristics make SRG cultures a powerful model for delineating the molecular basis of the transmembrane and intracellular signaling networks that stimulate or inhibit secondary active chloride transport in epithelia. Secondary active chloride transport occurs in a variety of epithelia, including those comprising both the proximal and distal segments of vertebrate nephrons.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology reporter 16 (1998), S. 129-131 
    ISSN: 1572-9818
    Schlagwort(e): Agrobacterium tumefaciens ; binary vector ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We report the construction of a binary vector for Agrobacterium tumefaciens-mediated transformation, pBIN20, which contains a superlinker region located between the left and right Ti border sequences. This vector, derived from pBI121, simplifies the cloning of plant expression cassettes and has been used in our laboratory to create lines of transgenic BY-2 tobacco cells. This new vector contains more than 20 unique restriction sites as well as the nptII selectable marker gene within the Ti-DNA borders.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    ISSN: 1432-203X
    Schlagwort(e): Gramineae ; GUS ; microprojectile bombardment ; pearl millet ; tissue culture ; transient gene expression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Transient GUS (β-glucuronidase) expression was visualized in whole and sectioned embryos of Pennisetum glaucum (L.) R. Br. (pearl millet) after microprojectile bombardment with pMON 8678 DNA. Strongest GUS expression occurred in cells located in the center of GUS positive spots with decreasing intensity in surrounding cells. GUS positive cells could be seen up to 12 cell layers beneath the epidermis. Needle-like crystals of the GUS assay product were found throughout the cytoplasm of GUS positive cells. The number of GUS positive spots was correlated to the microprojectile spread pattern on the medium surface. Shorter bombardment distances (6.6 and 9.8 cm) and the standard accelerator speed gave the best results for transient expression but also caused maximum tissue damage. The speed and distance, however, had little influence on the ability of bombarded embryos to form compact callus. The developmental stage of the bombarded immature embryos was the determining factor in the formation of compact callus, from which plants were regenerated.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell reports 10 (1991), S. 148-151 
    ISSN: 1432-203X
    Schlagwort(e): wheat ; rye ; embryogenesis ; growth ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The influence of the short arm of rye chromosome 1 (1RS) from Secale cereale var. Imperial on the growth and differentiation of callus cultures from wheat Triticum aestivum var. Chinese Spring immature embryos was analysed. This chromosome arm was found to stimulate both embryogenesis and the rate of growth of calli. Recombinant lines carrying segments of 1RS were used to delineate the regions of 1RS responsible for the tissue culture effects. The enhancement of embryogenesis and the stimulation of growth were shown to be associated with two distinct genetic regions of the chromosome arm; the former is located between the centromere and the Sec 1 locus, while the latter is situated in the immediate vicinity of the Sec 1 locus.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    ISSN: 1432-203X
    Schlagwort(e): Agrobacterium tumefaciens ; Allium cepa ; Antirrhinum majus ; Brassica campestris ; Glycine max ; Nicotiana tabacum ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Expiants of five plant species (Allium cepa, Antirrhinum majus, Brassica campestris. Glycine max, and Nicotiana tabacum) were co-cultivated with three Agrobacterium tumefaciens strains under different conditions to assess the effects of acetosyringone and medium pH on strain virulence. Tumours were incited on all dicotyledonous species by strains N2/73 and A281. The presence of acetosyringone during co-cultivation generally enhanced the virulence of these strains, most markedly N2/73 on A. majus and G. max, and A281 on G. max. Strain Ach5 was virulent only on N. tabacum in the absence of acetosyringone, which, when present, extended the host range to include A. majus. There was evidence to suggest that acetosyringone may suppress virulence in some strain/plant species interactions. Virulence was affected in some cases by medium pH, but there was no general effect across plant species.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell reports 10 (1991), S. 85-89 
    ISSN: 1432-203X
    Schlagwort(e): Agrobacterium rhizogenes ; alkamides ; Echinacea purpureal ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Echinacea purpurea seedlings were inoculated with several Agrobacterium rhizogenes strains in order to obtain hairy roots. Infection with A. rhizogenes strains LMG63 and LMG150 resulted in callus formation. Upon infection with strains ATCC 15834 and R1601 hairy roots were obtained. Opine detection confirmed transformation of E. purpurea. Comparative HPLC fingerprint analysis of the alkamides from natural plant source, control tissues, and transformed callus and roots indicated that transformed callus and hairy roots might be a promising source for continuous and standardized production of the dodeca-2E,4E,8Z,10E/Z-tetraenoic acid isobutylamide and related amides.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell reports 9 (1991), S. 549-554 
    ISSN: 1432-203X
    Schlagwort(e): Brassica campestris ; cotyledon culture ; histology ; organogenesis ; regeneration ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A system has been developed for efficient regeneration of shoots from Brassica campestris in vitro. Using 4-day old cotyledons with petioles as expiants and a combination of BA and NAA in the regeneration media, up to 70% of expiants produced shoots after 2 weeks in culture. The optimal conditions for regeneration were found to include a BA concentration of 2mgL−1 and NAA concentration of 1mgL−1. Light intensity had a profound effect on regeneration potential. The use of silver ions as an inhibitor of ethylene action reduced regeneration rates in this system. Rooting occured simultaneously with shoot formation on these media and the resultant shoots could be rooted readily on minimal medium. The genotype dependency was investigated and indicated that this method would be widely applicable to B. campestris cultivars. Regeneration of one cultivar, a high erucic acid type (R-500), was inefficient in the system described here. Histological studies indicated the development of multiple shoot primordia from the petiolar cut ends of the expiants after the initiation of meristematic activity in the cells about 100μm from the cut site within 2 days of culture initiation. The system described is compatible with previously reported Agrobacterium — mediated transformation protocols involving cotyledonary petioles.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 20 (1991), S. 437-439 
    ISSN: 1432-0983
    Schlagwort(e): Schizosaccharomyces pombe ; Saccharomyces cerevisiae ; β-glucuronidase ; Colony colour assay ; Fluorometric assay
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Expression of the β-galactosidase gene in yeast has served as a screening marker for many purposes. Here it is shown that in two yeasts, Saccharomyces cerevisiae and Schizosaccharomyces pombe, the β-glucuronidase (GUS) gene can be used as an alternative marker. Since the histochemical substrate can not be taken up by yeast cells, direct colony screening of plates was found to be impossible. However, by a replica plating technique, GUS expression became visibly detectable within 10 min when the GUS gene was strongly expressed. The staining method could still be performed for expression at a 100-fold lower level, but incubation times of several hours were needed. Furthermore, specific GUS expression levels of yeast protein extracts could be quantified by a fluorometric assay which is both very simple to perform and highly sensitive. Since the GUS gene can also tolerate large N-terminal fusions, this method should be particularly attractive for studying such diverse problems as transcriptional and translational regulation or subcellular localization in yeast.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Molecular and cellular biochemistry 105 (1991), S. 171-177 
    ISSN: 1573-4919
    Schlagwort(e): estrogen receptor ; transformation ; aging ; rat uterus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract The conformation of estrogen receptor (ER) and its in vitro transformation by RNase, Urea and ATP were analysed using the uteri of young (16 weeks) and old (92 weeks) rats. Following the digestion of ER with proteolytic enzymes like trypsin and chymotrypsin and the analysis of cleaved fragments by SDS-PAGE, similar pattern is observed in both ages. In vitro transformation of ER by RNase, Urea and ATP shows that the degree of transformation is lower in old than young. Furthermore, the transformed ER from old is less capable of binding to DNA than that from young. Thus our results show that the conformation of ER probably does not change with age, but the degree of transformation and the ability of transformed receptor to bind to DNA decrease with age.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 17 (1991), S. 167-174 
    ISSN: 1573-1561
    Schlagwort(e): Allelopathy ; Antennaria microphylla ; small everlasting ; Euphorbia esula ; leafy spurge ; tissue culture ; hydroquinone ; arbutin ; glucosyltransferase ; biotransformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Callus and suspension cultures ofAntennaria microphylla (small everlasting) and the noxious weedEuphorbia esula (leafy spurge) can glucosylate benzene-1,4-diol (hydroquinone) to the corresponding monoglucoside, arbutin. HPLC analysis of extracts from callus tissue corroborates the presence of hydroquinone in the cells of small everlasting. Constitutive levels of a UDPG-dependent glucosyltransferase were detected in cell-free extracts of this tissue. Although this detoxification enzyme was induced in leafy spurge suspension culture cells grown in the presence of hydroquinone, the activity was six-fold lower than that measured in small everlasting. Differential ability to detoxify hydroquinone provides a basis for the observed allelopathic interaction between small everlasting and leafy spurge.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Environmental and ecological statistics 5 (1998), S. 197-222 
    ISSN: 1573-3009
    Schlagwort(e): kriging ; non-separable space-time correlation ; spatial scale ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract We present an approach to estimate hourly grid-cell surface ozone concentrations based on observations from point monitoring sites in space, for comparison with grid-based results from the SARMAP photochemical air-quality model for a region of northern California. Statistical estimation is carried out on a transformed (square root) scale, followed by back-transforming to the original scale of ozone in parts per billion, adjusting for bias and variance. We estimate a spatially-varying diurnal mean structure and a non-separable space-time correlation structure on the transformed scale. Temporal pre-whitening is followed by modelling of a spatially non-stationary, diurnally-varying spatial correlation structure using a spatial deformation approach. Comparisons of SARMAP model results with the estimated grid-cell ozone levels are presented.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 13
    ISSN: 1573-5028
    Schlagwort(e): methylation ; Oryza sativa ; protoplasts ; transformation ; β-D-glucuronidase ; methotrexate ; hygromycin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Cell suspension-derived rice (Oryza sativa L.) protoplasts were transformed by direct gene uptake. PEG-mediated transformation was more efficient than electroporation. Plasmid DNA containing a hygromycin phosphotransferase (HPT) gene (which confers hygromycin resistance) driven by the CaMV 35S promoter and a β-D-glucuronidase (GUS) gene under control of the 1′, 2′ double promoter of the mannopine synthase (mas) locus of Agrobacterium tumefaciens was introduced into rice protoplasts. Southern analysis of DNA from transformed cell lines showed that the HPT and GUS genes were present intact. Both genes were expressed in transgenic cell suspensions. GUS activity was detected by histochemical staining of the cells and by enzyme assays. During a 12-day culture period the proportion of stained cells rose to a maximum and then decreased again. Considerably higher numbers of blue-stained cells were obtained when the transgenic cell lines were grown in the presence of 5-azacytidine. Transcripts of the GUS gene could not be detected, in contrast with the HPT gene. Plantlets were regenerated from one transgenic cell line. GUS activity was found in both leaf and root tissues of these plants, particularly, but not exclusively, in vascular bundles. A mouse dihydrofolate reductase coding sequence (DHFR), conferring methotrexate resistance, fused to the CaMV 35S promotor and the wild-type nopaline synthase (NOS) gene of A. tumefaciens were also introduced into rice protoplasts. Stable integration of both genes was confirmed by Southern analysis. Expression of the DHFR gene was demonstrated by high levels of resistance to methotrexate of the transgenic cell suspensions and by the presence of DHFR transcripts. Expression of the NOS gene at enzyme or RNA level was not detected. Southern analysis suggests that this gene was probably either methylated or scrambled in these lines.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 14
    ISSN: 1573-5028
    Schlagwort(e): Medicago sativa L. ; stress response ; tissue culture ; somatic embryogenesis ; heat shock protein (HSP)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have isolated two cDNA clones (Mshsp18-1; Mshsp18-2) from alfalfa (Medicago sativa L.) which encode for small heat shock proteins (HSPs) belonging to the hsp17 subfamily. The predicted amino acid sequences of the two alfalfa proteins are 92% identical and a similar degree of homology (90%) can be detected between Mshsp 18-2 and the pea hsp 17. In comparison to various members of small HSPs from soybean amino acid sequence similarities of 80–86% were identified. The alfalfa HSPs share a homologous stretch of amino acids in the carboxy terminal region with hsp22, 23, 26 from Drosophila. This region contains the GVLTV motif which is characteristic of several members of small HSPs. At room temperature alfalfa hsp 18 mRNAs were not detectable in root and leaf tissues but northern analysis showed a low level of expression in microcallus suspension (MCS). The transcription of Mshsp 18 genes is induced by elevated temperature, CdCl2 treatment and osmotic shock in cultured cells. In alfalfa somatic embryos derived from MCS a considerable amount of hsp 18 mRNA can be detected during the early embryogenic stages under normal culture conditions. The differential expression of these genes during embryo development suggests a specific functional role for HSPs in plant cells at the time of the developmental switch in vitro.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 15
    ISSN: 1573-5028
    Schlagwort(e): patatin ; promoter ; β-glucuronidase ; potato
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The class-specific expression of patatin genes was investigated by analysing four new patatin genes. A class I patatin gene from cv. Berolina as well as a class I and two class II patatin genes from the monohaploid cultivar AM 80/5793 were isolated and partially sequenced. Sequence comparison indicates rearrangements as the major source for the generation of diversity between the different members of the classes. The expression of single genes was studied in potato plants transformed with chimaeric genes where the putative patatin promoters were fused to the GUS reporter gene. A detailed histochemical analysis reveals that both class I genes are expressed as the previously described class I patatin gene B33 from cv. Berolina [1], i.e. in the starch-containing cells of potato tubers and in sucrose-induced leaves. The class II gene pgT12 shows the same pattern as the previously described class II gene pgT2 [2], i.e. expression in root tips and in the vascular tissue of tubers, whereas no activity was detectable for pgT4. Thus the expression pattern of both classes of genes seems to be stable at least within or even between different cultivars.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 16
    ISSN: 1573-4943
    Schlagwort(e): Conformational energy ; three-dimensional structure ; amino acid substitution ; c-abl oncogene ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Thebcr-abl chimeric gene of Philadelphia chromosome positive chronic myelogenous leukemias is only weakly transforming. This transformation activity is greatly enhanced by a Lys-for-Glu substitution at position 832 in the c-abl gene, as occurs in the highly transforming v-abl genes. It has been suggested that this mutation results in a significant structural change in the encoded protein product. Using conformational energy analysis, we have determined the allowed low-energy conformations for residues 828–836 of this protein with Lys and Glu at position 832. In both cases, the overwhelmingly preferred conformation for this region is a bend-helix motif. The helix terminates at residue 836, and there are no discernible differences in conformation between the Lys- and Glu-containing sequences. These results suggest that the activating amino acid substitution at position 832 in the c-abl protein product does not produce its effect via a local conformational change.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology 17 (1991), S. 837-851 
    ISSN: 1573-5028
    Schlagwort(e): Agrobacterium ; binary vector ; gene fusion ; β-glucuronidase ; T-DNA insertion ; transgenic tobacco
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A binary vector, pPRF120, was designed to detect T-DNA insertions within transcriptionlly active areas of the plant genome. Linked to the right-border repeat, the vector contains a promoterless β-glucuronidase (GUS) gene which can, upon integration into chromosomes, be activated by cis-acting regulatory elements. The vector also incorporates a chimeric marker gene conferring resistance to kanamycin to ensure recovery of gene fusions regardless of the extent of their tissue-specific or developmentally regulated expression, and to permit analysis of the frequency of plants which express the promoterless reporter. Approximately 1000 transgenic tobacco plants harboring pPRF120 were regenerated. Analysis of 52 individuals indicated that more than 80% contain single, intact copies of the T-DNA, regardless of their ability to express the promoterless GUS gene. Screening of leaf tissue from the 1000 pPRF120 transformants revealed that ca. 5% of the plants contained GUS activity. Fluorogenic and histological GUS assays were used to visualize and quantify tissue- and cell-specific gene expression. The potential usefulness of pPRF120 in comparison to other vectors designed to generate in vivo gene fusions is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology 16 (1991), S. 263-269 
    ISSN: 1573-5028
    Schlagwort(e): transformation ; enhancer trap ; β-glucuronidase ; potato
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A vector has been designed that contains a truncated CaMV (cauliflower mosaic virus) 35S promoter fused to a receptor gene encoding β-glucuronidase (GUS), placed adjacent to the left border sequence of an Agrobacterium vector. In potato plants transformed with this vector, different patterns of transcription were detected at high frequency using in situ assays for GUS activity. Previous studies in Drosophila using analogous vectors have shown that the new patterns of transcription in many cases reflect the patterns of expression of genes adjacent to the site of vector insertion. If this is also the case in plants, the vector described here will be useful in identifying the activity of genes in different cell types and will assist in determining their function.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 19
    ISSN: 1573-5028
    Schlagwort(e): recombinant ; phosphoenolpyruvate carboxylase ; C4 plant ; cDNA ; transformation ; Escherichia coli ; protein phosphorylation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Phosphoenolpyruvate carboxylase (PEPC)-deficient mutants ofEscherichia coli have been complemented with a plasmid bearing a full-length cDNA encoding the C4-type form ofSorghum leaf PEPC. Transformed cells grew on minimal medium. Two clones were selected which produce a functional and full-sized enzyme protein as determined by activity assays, immunochemical behavior and SDS-PAGE. In addition, regulatory phosphorylation of immunopurified recombinant PEPC was observed when the enzyme was incubated with a partially purified plant PEPC kinase. These results establish thatE. coli cells produce a genuine, phosphate-free, higher-plant PEPC. Application of immunoadsorbtion chromatography to bacterial extracts makes it possible to prepare highly pure protein available for biochemical studies.
    Materialart: Digitale Medien
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  • 20
    ISSN: 1573-5028
    Schlagwort(e): cassava ; Manihot esculenta ; transient gene expression ; particle gun ; β-glucuronidase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The bacterial gene encoding β-glucuronidase (GUS) was transiently expressed in cassava leaves following the introduction of the gene by microparticle bombardment. The DNA expression vector used to introduce the reporter gene is a pUC 19 derivative and consisted of a CaMV 35S promoter (P35S), the GUS coding region and 7S polyadenylation region. Several other promoters and regulating sequences were tested for efficiency in cassava leaves. Two derivatives of the P35S, one including a partial duplication of the upstream region of the P35S and the other containing a tetramer of the octopine synthase enhancer, were found to be expressed at three times the level of the P35S in cassava leaves. The ubiquitin 1 promoter fromArabidopsis thaliana was expressed at the same level as the P35S. No influence on the level of expression was observed when different 3′ ends were used. The biolistic transient gene expression system in cassava leaves allows rapid analysis of gene constructs and can serve as a preliminary screen for chimeric gene function in the construction of transgenic cassava plants.
    Materialart: Digitale Medien
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  • 21
    ISSN: 1432-1424
    Schlagwort(e): brush border membrane ; amiloride ; tissue culture ; intracellular pH ; fluorescence
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Summary The present study describes a new perfusion technique—based on the use of a routine spectrofluorometer—which enables fluorometric evaluation of polarity, regulation and kinetics of Na+/H+ exchange at the level of an intact monolayer. Na+/ H+ exchange was evaluated in bicarbonate-free solutions in OK (opossum kidney) cells, a renal epithelial cell line. Na+/H+ exchange activity was measured by monitoring changes in intracellular pH (pH i ) after an acid load, using the pH-sensitive dye 2′7′-bis (carboxyethyl) 5–6-carboxy-fluorescein (BCECF). Initial experiments indicated that OK cells grown on a permeable support had access to apical and basolateral perfusion media. They also demonstrate that OK cells express an apical pH i , recovery mechanism, which is Na+ dependent, ethylisopropylamiloride (EIPA) sensitive and regulated by PTH. Compared to resting conditions (pH i =7.68; pH o =7.4) where Na+/H+ exchange is not detectable, transport rate increased as pH i decreased. A positive cooperativity characterized the interaction of internal H+ with the exchanger, and suggests multiple H+ binding sites. In contrast, extracellular [Na+] increased transport with simple Michaelis-Menten kinetics. The apparent affinity of the exchanger for Na+ was 19mM at an intracellular pH of 7.1 and 60mM at an intracellular pH of 6.6. Inhibition of Na+/H+ exchange activity by EIPA was competitive with respect to extracellular [Na+] and theK i was 3.4 μM. In conclusion, the technique used in the present study is well suited for determination of mechanisms involved in control of epithelial cell pH i and processes associated with their polarized expression and regulation.
    Materialart: Digitale Medien
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  • 22
    ISSN: 1432-1424
    Schlagwort(e): intercellular communication ; gap junction ; connexin ; growth control ; cDNA ; connexin43 ; cell-cell channel ; junctional communication ; transformation ; cancer etiology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Summary Incorporation of the gene for connexin 43, a cell-cell channel protein of gap junction, into the genome of communication-deficient transformed mouse 10T1/2 cells restored junctional communication and inhibited growth. Growth was slowed, saturation density reduced and focus formation suppressed, and these effects were contingent on overexpression of the exogenous gene and the consequent enhancement of communication. In coculture with normal cells the growth of the connexin overexpressors was completely arrested, as these cells established strong communication with the normal ones. Thus, in culture by themselves or in coculture, the connexin overexpressor cells grew like normal cells. These results demonstrate that the cell-cell channel is instrumental in growth control; they are the expected behavior if the channel transmits cytoplasmic growth-regulatory signals.
    Materialart: Digitale Medien
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 41 (1998), S. 211-217 
    ISSN: 1871-4528
    Schlagwort(e): in vitro tuberization ; micropropagation ; mineral nutrition ; seed potato production ; Solanum tuberosum L. ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The effect of inorganic nitrogen nutrition on the induction and development of microtubers by cytokinin-induced tuberization was studied in four potato genotypes belonging to different maturity groups. The objective of this study was to investigate whether a reduction in total nitrogen level in the Murashige & Skoog medium would improve cytokinin-induced tuberization rate. The effect of three levels of total nitrogen (15, 30 and 45 meq) on tuberization was studied at constant (20 meq K) and varying potassium levels approximating to 5, 10 and 15 meq. Reducing the total nitrogen supply increased the number but decreased the size of nitrogen level on the rate of assimilate partitioning (harvest index) during cytokinin-induced microtuberization.
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  • 24
    ISSN: 1573-9368
    Schlagwort(e): sweet orange ; Citrus ; woody ; transformation ; Agrobacterium ; mature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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
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  • 25
    ISSN: 1573-9368
    Schlagwort(e): Saccharum ; Agrobacterium ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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
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  • 26
    ISSN: 1573-9368
    Schlagwort(e): Oryza sativa ; particle bombardment ; transformation ; transgenic rice
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We developed a practical and efficient gene transfer system for indica rice utilizing mature-seed derived explants and a simple bombardment device which uses compressed helium for accelerating DNA-coated metal particles. Unlike instruments which have been described in the literature previously, this new bombardment device, which is an improvement of the particle inflow concept, does not require vacuum. This attribute simplifies the transformation procedure significantly and it makes rice transformation technology accessible to laboratories which may not have the resources to invest in more expensive particle bombardment instruments. We determined experimentally that we could recover transgenic rice plants utilizing three different particle bombardment instruments at comparable frequencies.
    Materialart: Digitale Medien
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  • 27
    ISSN: 1573-9368
    Schlagwort(e): chimaera ; iterative culture ; regeneration ; strawberry ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Transgenic plants of strawberry cultivar Totem were developed by Agrobacterium-mediated transformation using a plasmid vector containing gus and nptII genes. Parallel experiments were carried out with and without repeated subculturing (iterative cultures) for generation of transgenic shoots on selection medium. The selection levels in the non-iterative pathway were kept constant, while in the iterative protocol, stepwise increase of selection pressure was applied at different stages of tissue growth. Rooted transgenic plants obtained via both protocols were outplanted in soil. Random leaf samples of greenhouse-grown transgenics were analysed for the presence of gus gene sequences by Southern hybridization as well as gus expression on leaf and petiole tissues by X-Gluc histological assay. Random leaf samples analysed from individual transgenic events developed under iterative culture were positive for the gus insert as verified by Southern analysis confirming the presence of transgenes and lack of chimaeras. Leaf samples of the transgenic events from the non-iterative protocol were either positive or negative on Southern analysis indicating the chimaeric nature of the transgenic plants. The absence of gus sequences in the transgenic plants grown under the non-iterative protocol reinforced the necessity of iterative cultures along with stepwise increase in selection levels for generating non-chimaeric transgenics in strawberry. The gus expression was highly variable, irrespective of the iterative or non-iterative protocol used for transformation. We conclude that strawberry is highly prone to develop chimaeric transgenics if derived from primary regenerants and that the iterative culture technique effectively converts chimaeras to pure line transgenic plants
    Materialart: Digitale Medien
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  • 28
    ISSN: 1572-9788
    Schlagwort(e): glycerol-3-phosphate acyltransferase ; phosphatidylglycerol ; chilling tolerance ; transformation ; fatty acid composition ; Oryza sativa L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The chilling sensitivity of several plant species is closely correlated with the levels of unsaturation of fatty acids in the phosphatidylglycerol (PG) of chloroplast membranes. Plants with a high proportion of unsaturated fatty acids, such as Arabidopsis thaliana, are resistant to chilling, whereas species like squash with only a low proportion are rather sensitive to chilling. The glycerol-3-phosphate O-acyltransferase (GPAT) enzyme of chloroplasts plays an important role in determining the levels of PG fatty acid desaturation. A cDNA for oleate-selective GPAT of Arabidopsis under the control of a maize Ubiquitin promoter was introduced into rice (Oryza sativa L.) using the Agrobacterium-mediated gene transfer method. The levels of unsaturated fatty acids in the phosphatidylglycerol of transformed rice leaves were found to be 28% higher than that of untransformed controls. The net photosynthetic rate of leaves of transformed rice plants was 20% higher than that of the wild type at 17°C. Thus, introduction of cDNA for the Arabidopsis GPAT causes greater unsaturation of fatty acids and confers chilling tolerance of photosynthesis on rice.
    Materialart: Digitale Medien
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  • 29
    ISSN: 1572-9788
    Schlagwort(e): Bt genes ; transformation ; protection against insects ; cry1Ia5
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A cry1Ia5 insecticidal toxin coding gene has been cloned from an Indian isolate of Bacillus thuringiensis. Sequence analyses of the cry1Ia5 gene revealed the absence of potential polyadenylation signal sequences thus making it a suitable candidate for expression in plants without extensive modification. This possibility was examined by subcloning the cry1Ia5 gene into a plant expression vector and then transferring it to Nicotiana tabacum through Agrobacterium-mediated transformation. Our results demonstrate that N. tabacum with a stably integrated native cry1Ia5 gene afforded complete protection against predation by Heliothis armigera. Forty three percent of the transgenic plants displayed a high level of protection against insect predation. The protection obtained in transgenic plants with the cry1Ia5 gene was comparable to that obtained with the synthetically modified cry1A(b) or cry1A(c) genes. The results demonstrate that novel insecticidal genes already exist in nature that do not require extensive modifications for efficient expression in plants.
    Materialart: Digitale Medien
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  • 30
    ISSN: 1572-9788
    Schlagwort(e): antisense ; chalcone synthase ; flower colour ; lisianthus ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Three cultivars of lisianthus (Eustoma grandiflorum (Grise.)) were transformed with a homologous antisense CHS cDNA via Agrobacterium-mediated transformation. Over 50% of the transgenics derived from the purple flowering lines exhibited an altered flower colour pattern ranging from small streaks of white on the wild-type purple background through to completely white flowers. A significant portion of the transgenic lines showed unstable phenotypes. Northern and biochemical analysis showed that the altered flower patterns were associated with a loss of CHS gene transcript and a corresponding loss of CHS enzyme activity. In the white flowering line the level of total flavonoids was reduced to ca. 2.0% of the wild-type level. Some of the transgenic plants also exhibited alterations in flower form such as the formation of frilled petal tips and reduced flower opening. Several of the new patterned lines are being evaluated for stability and possible commercial release.
    Materialart: Digitale Medien
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  • 31
    ISSN: 1572-9788
    Schlagwort(e): Indica rice ; cell suspension ; transformation ; Xa21 ; bacterial leaf blight
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The agronomically important Indica (group 1) rice varieties IR64, IR72, hybrid restorer line Minghui 63, and BG90-2 were co-transformed by microbombardment of embryogenic suspensions with plasmids that contain the Xa21 gene which confers resistance to Xanthomonas oryzae pv. oryzae and the hph gene for resistance to hygromycin B. Six of the 55 transgenic R0 plant lines containing the Xa21 gene displayed high levels of resistance to the pathogen, and no partial resistance was observed. The trait was stably inherited in subsequent generations, and transgenic plants are currently in field tests. The ability to transfer agronomically important genes into elite Indica rice varieties demonstrates the applicability of genetic engineering for the agronomic improvement of rice.
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Molecular breeding 4 (1998), S. 119-127 
    ISSN: 1572-9788
    Schlagwort(e): Daucus carota ; Agrobacterium tumefaciens ; genetic transformation ; β-glucuronidase ; 35S promoter
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A protocol is presented for the efficient transformation of carrot (Daucus carota L. cv. Nantaise) by Agrobacterium tumefaciens. The binary vector contained the marker gene β-glucuronidase (GUS), driven by the 35S promoter of cauliflower mosaic virus, and the nptII gene, which confers kanamycin resistance. Highest T-DNA transfer rates were obtained by co-cultivating bacteria with hypocotyl segments of dark-grown seedlings on solidified B5 medium containing naphthaleneacetic acid and 6-benzylaminopurine. After 2 days, bacterial growth was stopped with antibiotics. Two weeks later, the explants were placed on agar containing the kanamycin derivate geneticin; antibiotic-resistant calli developed during the following 4 weeks. Suspension cultures were obtained from resistant calli and plants regenerated via somatic embryogenesis in liquid culture. The majority of plants were phenotypically normal and, depending on the Agrobacterium strain used, harbored single or multiple copies of the T-DNA. About equal levels of GUS activity were found in different organs of young plants up to 6 weeks after embryogenesis. In leaves of older plants, GUS activity was markedly reduced, whereas the activities in phloem and xylem parenchyma cells of developing tap roots were still high and fairly uniform. Thus, the 35S promoter may be a useful tool to drive the expression of transgenes in developing carrot storage roots.
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Molecular breeding 4 (1998), S. 531-541 
    ISSN: 1572-9788
    Schlagwort(e): Agrobacterium ; Brassica oleracea ; cauliflower ; regeneration ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: 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.
    Materialart: Digitale Medien
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  • 34
    ISSN: 1572-9788
    Schlagwort(e): amylose ; antisense RNA ; endogenous allele ; Solanum tuberosum ; T-DNA insertion ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The T-DNA composition was analysed of twelve potato genotypes obtained after transforming a tetraploid cultivar with an antisense granule-bound starch synthase (GBSSI) gene. In five transformants (labelled TB50 nos.) the antisense GBSSI gene was driven by the CaMV 35S promoter, while in the remaining seven (labelled TBK50 nos.) the GBSSI promoter was used. In these twelve transformants the antisense effect on amylose production in potato tuber starch ranged from complete suppression to no discernible inhibition, and the number of T-DNA insertions ranged from one to at least fifteen. The antisense effect of individual T-DNA loci in progeny of these transformants was studied. Progeny containing a single T-DNA showed no inhibition of GBSSI activity. Only multiple, linked T-DNA insertions resulted in substantial antisense inhibition. T-DNA fragments present in duplex in selfed progeny resulted in a larger antisense effect than that in the parent (which contained the T-DNA insertions in simplex). Furthermore, the antisense effects of some T-DNA-containing linkage groups were influenced by the composition of endogenous GBSSI alleles. For practical breeding this implies that (1) the efficiency of obtaining primary potato transformants showing complete inhibition of GBSSI gene expression by antisense RNA is genotype-dependent, and (2) many transformants have to be produced per genotype to be able to select plants with maximum suppression of GBSSI and a minimum number of T-DNA loci.
    Materialart: Digitale Medien
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  • 35
    ISSN: 1573-5028
    Schlagwort(e): β-glucuronidase ; jasmonate ; retrotransposon tobacco ; wounding
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The tobacco retrotransposon Tto1, one of a few active retrotransposons of plants, has been shown to be activated by tissue culture. Its transposition is regulated mainly at the transcriptional level. It is shown here that expression of Tto1 can be induced in leaves of tobacco by wounding stress. Exogenous supply of methyl jasmonate, which is known to be a potent inducer of certain wound-responsive genes in plants, also induces Tto1 RNA expression. Tto1 RNA was detected within 2 to 4 h after wounding/cutting treatment, and increased levels of Tto1 RNA were observed during subsequent incubation periods for 48 h. Expression of Tto1 RNA after cutting treatment was induced more significantly in young expanding leaves rather than in older mature leaves, suggesting that developmental or physiological factors may be required for the strong response to Tto1 transcription to wounding stimuli. Experiments with transgenic tobacco plants carrying the Tto1-LTR: β-glucuronidase fusion gene (LTR:GUS) revealed that Tto1 actually contains cis-regulatory regions in response to wounding and methyl jasmonate. These findings are discussed in relation to the mechanism of transcriptional activation and the evolutionary role played by retrotransposons.
    Materialart: Digitale Medien
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  • 36
    ISSN: 1573-5028
    Schlagwort(e): β-glucuronidase ; protein degradation ; firefly luciferase ; N-end rule ; plant ; ubiquitin pathway
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The ubiquitin pathway targets proteins for degradation through the post-translational covalent attachment of the 76 amino acid protein ubiquitin to ∈-amino lysyl groups on substrate proteins. Two instability determinants recognized by the ubiquitin pathway in Saccharomyces cerevisiae have been identified. One is described by the N-end rule and requires specific destabilizing residues at the substrate protein N-termini along with a proximal lysyl residue for ubiquitin conjugation. The second is a linear uncleavable N-terminal ubiquitin moiety. The ability of these two determinants to function in higher plants was investigated in tobacco protoplast transient transfection assays using DNA encoding variants of well characterized reporter enzymes as substrates: firefly luciferase that is localized to peroxisomes (pxLUC), a cytosolic version of LUC (cLUC), and Escherichia coli β-glucuronidase (GUS). cLUC with phenylalanine encoded at its mature N-terminus was 10-fold less abundant than cLUC with methionine at its mature N-terminus. GUS with phenylalanine encoded at its mature N-terminus was 3-fold less abundant than GUS with methionine at its mature N-terminus. The presence of a uncleavable N-terminal ubiquitin fusion resulted in 50-fold lower protein accumulation of cLUC, but had no effect on GUS. Both instability determinants had a much larger effect on cLUC than on pxLUC, suggesting that these degradation signals are either unrecognized or poorly recognized in the peroxisomes.
    Materialart: Digitale Medien
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  • 37
    ISSN: 1573-5028
    Schlagwort(e): Agrobacterium ; apple ; GFP ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Plant growth regulation 25 (1998), S. 177-180 
    ISSN: 1573-5087
    Schlagwort(e): Blue Squill ; Hyacinthaceae ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Primary bulb explants of Scilla natalensis were cultured in vitro on modified MS medium. Some of these explants initiated shoots, which provided a sterile source of secondary leaf and bulb explants. The secondary explants responded similarly to various combinations of plant growth regulators. Shoots were initiated spontaneously on medium containing no plant growth regulators. The number of shoots initiated was increased by the addition of kinetin or thidiazuron (TDZ) alone, but was reduced by the addition of indole-3-acetic acid (IAA) or naphthalene acetic acid (NAA) alone. Optimal shoot initiation occurred on medium containing 1 to 2 mg l−1 kinetin and 1 to 2 mg l−1 IAA. These shoots were rooted on medium containing 1 mg l−1 IAA. The plantlets were successfully acclimatised in the misthouse/shadehouse.
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  • 39
    ISSN: 1573-5036
    Schlagwort(e): blue-green algae ; iron ; manganese ; submerged soils ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract N2-fixing blue-green algae (Cyanobacteria), besides enriching soils with N and organic carbon, may modify a number of chemical and electro-chemical properties of the soils resulting in a change in availability of some micronutrient elements. Keeping this in view, an experiment was conducted to study the effects of growth and subsequent decomposition of blue-green algae on changes in the different forms of Fe and Mn in four soils under submerged condition. A mixed algal culture containing Anabaena, Nostoc, Cylindrospermum, and Tolypothrix was used as inoculum. It was allowed to grow for 2 months, after which the soils were sequentially extracted with (i) M NH4OAc (pH 7.0), (ii) M K4P2O7, (iii) 0.1 M NH2OH.HCl (pH 2.0), (iv) 0.2 M (NH4)2C2O4 (pH 3.0) and (v) 0.1 M ascorbic acid to obtain water-soluble plus exchangeable, organically bound, easily reducible, amorphous oxides-and crystalline oxides-bound forms of Fe and Mn, respectively, both during the growth as well as the subsequent in-situ decomposition of the algal biomass in soils. Iron and Mn in the extracts were estimated by atomic absorption spectrophotometry. The results showed that growth of blue-green algae in submerged rice soils caused a decrease in the NH4OAc-extractable forms of Fe and Mn with concomitant increases in all the other four determined forms of the elements. Such decreases and/or increases in different forms of Fe and Mn in soils were explained as being due to release of O2, addition of organic matter and liberation of extracellular organic compounds by the blue-green algae during their growth. The decomposition of algal biomass resulted in an increase in the NH4OAc-, K4P2O7- and (NH4)2C2O4-extractable forms of Fe and Mn with a simultaneous decrease in the NH2OH · HCl- and ascorbic acid-extractable forms. Development of strong reducing conditions and formation of organic acids with chelating properties were suggested as being the cause of the above changes. The implication of these changes in the forms of Fe and Mn for the Fe and Mn nutrition of rice plants were discussed.
    Materialart: Digitale Medien
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  • 40
    ISSN: 1573-5036
    Schlagwort(e): Acetobacter diazotrophicus ; endophytic diazotrophic bacteria ; micropropagated plants ; nitrogen fixation ; sugar cane ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Micropropagated plantlets of sugar cane were inoculated with the N2-fixing bacterium Acetobacter diazotrophicus. Various modifications on the basic plant culture medium MS were made for the plant/bacteria association. The protocol required the inoculation of the bacteria at the end of the rooting period in a medium without hormones or vitamins, and with the concentration of sugar and mineral nutrients reduced by a factor of 10. Individual plants were inoculated with A. diazotrophicus and maintained under the appropriate light and temperature condition used for micropropagation up to 7 days. The system favored the infection and the establishment of the bacteria within the plant tissue. Bacteria colonized the plant tissue and accumulated in inter-cellular cavities and the region of lateral root emergence and also colonizes the xylem vessels. The inoculated plantlets were subsequently transferred to the acclimatization phase and after 30 days it was possible to isolate the bacteria from plant tissue. This protocol permitted studies of infection and comparison among strains.
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  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 27 (1991), S. 161-168 
    ISSN: 1573-5044
    Schlagwort(e): aspen ; growth suspension ; phenotypic variation ; ultra-structure ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Shoot cultures of P. alba x P. grandidentata ‘Crandon’ were maintained for more than 5 years at 4°C with minimal growth. The highest survival after 2 years and 5 years of cold storage were 70% and 25% respectively using 1-month of pre-storage culture on MS medium containing 1.33 μM BA. When 5-year-old cold-stored shoot cultures were transferred to the greenhouse, color variations were observed. The frequencies of albino and red pigmented plants were 0.25% and 12.8%, respectively. A rosette type growth pattern was also observed on 0.3% of the long-term cold-stored plants. During long-term cold storage there were local disruption of cambium connections and the accumulations of chemicals in some cells, as observed by light microscopy.
    Materialart: Digitale Medien
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 54 (1998), S. 97-104 
    ISSN: 1573-5044
    Schlagwort(e): androgenesis ; oat ; tissue culture ; heat treatment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effect of stress pretreatments on embryo induction in anther cultures of selected genotypes of Avena sativa and A. sterilis was tested. A heat pretreatment of isolated anthers at +32°C for 5 days was best for the A. sativa line WW 18019 and for A. sterilis line CAV 2648. Genotype dependency may exist since in ‘Stout’ heat pretreatment did not increase embryo production. For A. sterilis 13 green and three albino regenerants were produced, of which five plants (haploids) survived transfer to the greenhouse. For A. sativa, 30 various differentiation media/treatment combinations were used in an attempt to regenerate plants from embryos, with no success. Seven day cold treatment of cut tillers increased slightly the response level in ‘Stout’ and was routinely used in subsequent experiments. Maltose proved to be better then sucrose as a carbon source for the genotypes tested. Fourteen percent maltose promoted the highest induction in A. sterilis, but the quality of embryos was improved in the presence of 10% maltose for both species. Sub-optimal carbohydrate levels did not enhance embryo induction in oats.
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  • 43
    ISSN: 1573-5044
    Schlagwort(e): cell suspension culture ; embryogenic callus ; nucellar embryos ; plant regeneration ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Somatic embryogenesis was induced and plant regeneration was obtained in 11 different genotypes of sweet orange navel group [Citrus sinensis (L.) Osb.] from cultures of stigma/style explants and undeveloped ovules. Explants were cultured on 3 different modifications of Murashige and Skoog medium: 500 mg l-1 malt extract; 500 mg l-1 malt extract and 4.6 μM kinetin; and 500 mg l-1 malt extract and 13.3 μM 6-benzylaminopurine. Sucrose (146 mM) was used as carbon source. Somatic embryogenesis occurred 1–3 months after culture initiation from undeveloped ovule and stigma/style cultures of all the genotypes tested. Somatic embryos developed into plantlets with a high frequency (74%) after transfer to Murashige and Skoog medium supplemented with 146 mM sucrose and 500 mg l-1 malt extract. Plants were successfully transferred to soil.
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 55 (1998), S. 31-38 
    ISSN: 1573-5044
    Schlagwort(e): agar/Gelrite combination ; aminoglycosides ; β-glucuronidase ; Malus × domestica Borkh ; Marshall McIntosh ; neomycin phosphotransferase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The goal of this research was to develop an efficient transformation system for 'Marshall McIntosh' apple. To determine the optimum combination of agar and Gelrite gelling agents in the media to maximize regeneration and minimize hyperhydicity (vitrification), the following combinations of agar (A)+Gelrite (G) in g l-1 were tested: 7.0 A+0 G; 5.2 A+0.6 G; 3.5 A+2.5 G; 1.7 A+1.8 G; and 0 A+2.5 G. Both 5.2 A+0.6 G and 3.5 A+1.2 G provided greatest regeneration of healthy non-hyperhydric shoots. To determine the optimal concentration of aminoglycoside for the selection and regeneration of transgenic 'Marshall McIntosh' on agar-Gelrite-based media, kanamycin was tested at 0, 10, 25, 50, 75 and 100 mg l-1, and paromomycin was tested at 0, 50, 100, 150, 200 and 250 mg l-1. Kanamycin was more effective than paromomycin in the initial selection of transgenics. For selection of transformants of 'Marshall McIntosh', the use of kanamycin at 25 mg l-1on 5.2 A+0.6 G solidified medium is suggested. By optimizing the medium and selection conditions, a protocol was developed that resulted in four transgenic lines as confirmed by a GUS assay, NPT II ELISA, PCR, and Southern analysis. In repeated experiments with this protocol, transformation efficiencies of 3.1 and 2.6% were obtained.
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  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 100 (1998), S. 219-223 
    ISSN: 1573-5060
    Schlagwort(e): cereals ; wheat ; transformation ; genetic modification ; transgenic plants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A method for efficient genetic transformation of wheat has been developed using immature embryos as targets for microprojectile-mediated gene transfer and a helium driven particle delivery system. Screening and selection of transgenic cells, somatic embryos and regenerated plants are performed with the gus-gene and the phosphinothricin acetyl transferase (bar) gene coding for Basta-resistance as the selectable marker. On average, one fertile transgenic plant can be obtained from about 100 microprojectile treated, immature embryos. The number of integrated copies of the transferred gene ranges from 1 up to about 10. Stable integrated genes are inherited in most of the transgenic lines in a normal mendelian fashion segregating 3:1 in the F2. Homozygous, as well as heterozygous, lines have been followed and analysed genetically at the molecular level and up to F5. Apart from normal stable gene expression, examples have also been found which showed a loss of gene activity or unexpected segregation pattern. For applied aspects, different genes are transferred aiming for improved disease resistance, modification of quality, or other characteristics. First results from these transgenic lines are reported, and problems still existing with the production of stable transgenic wheat lines are discussed.
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  • 46
    ISSN: 1573-5060
    Schlagwort(e): Agrobacterium rhizogenes ; antisense RNA ; granule-bound starch synthase ; Solanum tuberosum ; starch composition ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Granule-bound starch synthase (GBSS) catalyses the synthesis of amylose in starch granules. Analysis of antisense RNA mediated inhibition of GBSS gene expression in large numbers of tubers from in vitro grown, greenhouse grown and field grown transgenic potato plants revealed stable and total inhibition of GBSS gene expression in one clone. In three other transgenic genotypes partial and unstable inhibition was found. In these genotypes both GBSS activity and amylose content were remarkably reduced compared with the non-transformed control genotype. No relationship was found between the level of inhibition of GBSS gene expression and yield and dry matter content.
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  • 47
    ISSN: 1573-5060
    Schlagwort(e): Sorghum bicolor L. Moench ; tissue culture ; callus ; haploid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Twenty-five inbred lines, including grain and forage types from the USA and China, two hybrids, one Sorghum almum, and one Parasorghum (S. versicolor) were tested for their response to anther culture. Three nutrient media were effective in inducing anther calli from six cultivars (Xin White, TX 403-TSB, DDY Sommer Milo, TX 2779, Brawley, and Spur Federal) and one was effective for plant regeneration for one cultivar, Xin White. Averaged over media, callus induction frequency (number of calli per 100 anthers) was highest in cultivars Xin White and TX 403-TSB (6.7 and 3.9%, respectively). The means of cultivars for media C17-2 and Ms-t-z-2, 4.3 and 3.2%, respectively, were superior to that for medium 85D3-2 (0.1%). Expressed as an average of the six cultivars and three media the mean calli induction frequency was 2.6%; however, differential responses of genotype and medium were noted. Among the 10 regeneration media tested, medium MS-d-4 containing Murashige and Skoog basal components plus 2.0 mg/l indole-3-acetic acid (IAA) and 2.5 mg/l kinetin was the most effective for plant regeneration. Numbers of albino plants and calli developing only roots increased directly with callus-induction time, whereas the frequency of plant regeneration decreased. Regenerated plants had varied numbers of chromosomes in root tip cells: 10, 15, 20, 40, and 60. The 29 regenerated plants that reached maturity, however, were highly fertile and contained only 10 bivalents in pollen mother cells. Normal chromosome number and behavior for the regenerated plants suggest that induced calli originated from cells other than microspores. However, spontaneous chromosome doubling in microspore-derived haploids may occur. The appearance of albinos also implies that haploids may have been produced from anther culture.
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  • 48
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 55 (1991), S. 157-169 
    ISSN: 1573-5060
    Schlagwort(e): gene transfer ; genetic manipulation ; chimaeric genes ; legumes ; transformation ; somatic hybridisation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The merits and limitations of somatic cell techniques involving Agrobacterium-mediated transformation, direct gene transfer and protoplast fusion, are discussed in relation to the genetic improvement of forage and grain legumes. Whilst progress with legumes is limited compared to that with plants of other families such as the Solanaceae, the fact that many legumes are readily amenable to tissue culture now permits somatic cell techniques to be targetted to these species. Future development of the subject will necessitate close collaboration between molecular biologists and plant breeders to enable novel plants generated by in vitro technologies to be incorporated into conventional breeding programmes.
    Materialart: Digitale Medien
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  • 49
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 85 (1955), S. 97-100 
    ISSN: 1573-5060
    Schlagwort(e): Agrobacterium ; transformation ; lily ; β-glucuronidase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: 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.
    Materialart: Digitale Medien
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  • 50
    ISSN: 1573-5060
    Schlagwort(e): Hordeum vulgare ; isolated microspores ; particle bombardment ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary A highly regenerable, isolated microspore system for barley, Hordeum vulgare L. cv. Igri, has been developed which is amenable to transformation studies using particle bombardment. The system allows DNA to be delivered to microspores at the single cell stage and both transient and stable transformation events have been demonstrated. The potential advantages of using isolated microspores as the target tissue in routine transformation systems are discussed.
    Materialart: Digitale Medien
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  • 51
    ISSN: 1573-5060
    Schlagwort(e): Lycopersicon ; tomato ; tomato spotted wilt virus ; tospovirus ; transformation ; virus resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Tomato spotted wilt virus (TSWV) causes significant economic losses in the commercial culture of tomato (Lycopersicon esculentum Mill.). Culture practices and introgression of natural sources of resistance to TSWV have only been marginally effective in controlling the TSWV disease. Recently however, high levels of protection against TSWV have been obtained by transforming tobacco with a chimaeric gene cassette comprising the TSWV nucleoprotein gene. This report demonstrates the successful application of this newly-created TSWV resistance gene in cultivated tomato. Transformation of an inbred tomato line with the TSWV nucleoprotein gene cassette resulted in high levels of resistance to TSWV that were maintained in hybrids derived from the parental tomato line. Therefore, transformant lines carrying the synthetic TSWV resistance gene make suitable progenitors for TSWV resistance to be incorporated into the breeding programmes of tomato.
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  • 52
    ISSN: 1573-5060
    Schlagwort(e): microprotoplast fusion ; partial genome transfer ; monosomic additions ; kanamycin resistance ; β-glucuronidase ; gene expression ; potato
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Various aspects of a microprotoplast fusion technique and the strategies followed for intergeneric partial genome transfer (one or a few chromosomes) and alien genes from sexually-incongruent donor species to recipient species are described. The essential requirements of the microprotoplast fusion technique are the induction of micronuclei at high frequencies, as well as the isolation and enrichment of sub-diploid microprotoplasts in donor species, efficient fusion of the donor microprotoplasts with normal recipient protoplasts and stable regeneration of plants from fusion products. The results on the production of microprotoplast hybrid plants between the transformed donor lines of Solanum tuberosum and Nicotiana Plumbaginifolia carrying various genetic markers, and a recipient line of Lycopersicon peruvianum or Nicotiana tabacum, and on the transfer and expression of alien genes (kanamycin resistance, β-glucuronidase) are presented. The data obtained on microprotoplast hybrid plants between S. tuberosum and L. peruvianum showed that many of the hybrids contained one potato chromosome carrying nptII and GUS, and 24 or 48 L. peruvianum chromosomes (monosomic additions), and that they were male-and female-fertile. Various applications of chromosome transfer by this technique, especially for economically-important traits (e.g. disease or stress resistance) from sexually-incompatible wild species, for construction of chromosome-specific DNA libraries through microdissection and microcloning of chromosomes, or by flow-sorting of chromosomes for genome analysis, are discussed.
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  • 53
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 85 (1955), S. 295-302 
    ISSN: 1573-5060
    Schlagwort(e): tissue culture ; somaclonal variation ; plant breeding
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Somaclonal variation is a tool that can be used by plant breeders. The review examines where this tool can be applied most effectively and the factors that limit or improve its chances of success. The main factors that influence the variation generated from tissue culture are (1) the degree of departure from organised growth, (2) the genotype, (3) growth regulators and (4) tissue source. Despite an increasing understanding of how these factors work it is still not possible to predict the outcome of a somaclonal breeding programme. New varieties have been produced by somaclonal variation, but in a large number of cases improved variants have not been selected because (1) the variation was all negative, (2) positive changes were also altered in negative ways, (3) the changes were not novel, or (4) the changes were not stable after selfing or crossing. Somaclonal variation is cheaper than other methods of genetic manipulation. At the present time, it is also more universally applicable and does not require ‘containment’ procedures. It has been most successful in crops with limited genetic systems and/or narrow genetic bases, where it can provide a rapid source of variability for crop improvement.
    Materialart: Digitale Medien
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  • 54
    ISSN: 1573-5060
    Schlagwort(e): alfalfa ; alpha-amylase ; field performance ; manganese-dependent lignin peroxidase ; Medicago sativa ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Transgenic alfalfa plants expressinBacillus licheniformis alpha-amylase and mangaese-dependent lignin peroxidase (Mn-P) from Phanerochaete chrysosporium were produced using the Agrobacterium tumefaciens transformation system. In each case, there was a range of expression of the introduced gene among independent transgenic plants. Plants producing alpha-amylase showed no alteration of phenotype. Production of Mn-P in alfalfa, howeven, in most cases adversely affected plant growth and development. Affected plants were stunted with yellowing foliage, but survived and produced seed. Results from field trials showed that Mn-P production in transgenic alfalfa reduced dry matter yield and plant height. The extent of these symptoms and yield reduction was, for the most part, related to the level of foreign protein production as estimated by Western analysis. Field data from transgenic plants expressing alpha-amylase showed that there was no effect of foreign protein production on plant performance. Expression of Mn-P was shown to segregate in sexual progeny derived from transgenic plants.
    Materialart: Digitale Medien
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  • 55
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology 38 (1998), S. 597-607 
    ISSN: 1573-5028
    Schlagwort(e): transgene silencing ; epigenetics ; transgene expression ; transgenic plants ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract An irregular pattern of transgene silencing was revealed in expression and inheritance studies conducted over multiple generations following transgene introduction by microprojectile bombardment of allohexaploid cultivated oat (Avena sativa L.). Expression of two transgenes, bar and uidA, delivered on the same plasmid was investigated in 23 transgenic oat lines. Twenty-one transgenic lines, each derived from an independently selected transformed tissue culture, showed expression of both bar and uidA while two lines expressed only bar. The relationship of the transgenic phenotypes to the presence of the transgenes in the study was determined using (1) phenotypic scoring combined with Southern blot analyses of progeny, (2) coexpression of the two transgenic phenotypes since the two transgenes always cosegregated, and (3) reactivation of a transgenic phenotype in self-pollinated progenies of transgenic plants that did not exhibit a transgenic phenotype. Transgene silencing was observed in 19 of the 23 transgenic lines and resulted in distorted segregation of transgenic phenotypes in 10 lines. Silencing and inheritance distortions were irregular and unpredictable. They were often reversible in a subsequent generation of self-pollinated progeny and abnormally segregating progenies were as likely to trace back to parents that exhibited normal segregation in a previous generation as to parents showing segregation distortions. Possible causes of the irregular patterns of transgene silencing are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 56
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 53 (1998), S. 91-98 
    ISSN: 1573-5044
    Schlagwort(e): Rosacee ; Cydonia oblonga ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effect of light quality on somatic embryogenesis in quince BA 29 was investigated. 2,4-D induced leaves were exposed for 25 days to the following light quality treatments: dark, far-red, far-red+blue, far-red+red, blue, white, red+blue, red. After a further 20 days of white light exposure, somatic embryo production was recorded. Somatic embryogenesis was highest in cultures subjected to red light treatment, and decreased progressively with the transition to red+blue and to white. Overall, embryogenic competence showed a correlation with photoequilibrium. Phytochrome appeared to be inductive although this effect was adversely influenced by the blue absorbing photoreceptor, in particular at low photoequilibrium. Independently of light treatments applied, somatic embryos frequently showed severe morphological abnormalities. Conversion of somatic embryos to plantlets was not observed.
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  • 57
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 53 (1998), S. 127-134 
    ISSN: 1573-5044
    Schlagwort(e): Dicamba ; protocorm ; 2iP ; callus ; Xanthosoma sagittifolium ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effects of various growth regulators on morphogenesis from cocoyam tissues (Xanthosoma sagittifolium) were investigated. Calluses were initiated from shoot tip and petiole explants and proliferated on medium containing 1.36 μM dicamba. Callus production was significantly greater from petioles than from shoot tips. Thidiazuron (0.045 μM) enhanced callus production when dicamba (13.5 μM) was used, and was more favorable to petioles than shoot tips. Friable shoot tip callus was subcultured into liquid media containing either 1.36 μM dicamba alone, 1.35 μM 2,4-D + 0.46 μM kinetin or 1.36 μM dicamba + 0.46 μM kinetin to induce adventive regeneration. Tissues producing single or aggregated shoot buds were subcultured into media containing 0, 0.049 and 0.49 μM 2-isopentenyladenine where bud multiplication and shoot regeneration were observed. Bud aggregates were formed from callus in liquid cultures containing 1.36 μM dicamba, 1.36 μM dicamba + 0.46 μM kinetin or 1.35 μM 2,4-D + 0.46 μM kinetin. Shoot bud clumps which remained green produced shoots, daughter buds, and plantlets in stationary and agitated liquid media containing 0, 0.049 and 0.49 μM 2iP.
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  • 58
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 55 (1998), S. 115-118 
    ISSN: 1573-5044
    Schlagwort(e): Asterareae ; Helianthus tuberosus ; microtuber ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Clonal micropropagation of Jerusalem artichoke (Helianthus tuberosus L.) was initiated from axillary meristems of lateral shoots of field-grown plants on medium with MS salts, 2% sucrose, 1 mg l-1 thiamine-HCl, 1 mg l-1 IAA and 0.6% agar. Plantlets were cut into nodal sections and used for subsequent subcultures and for microtuber induction. Microtubers were induced from axillary meristems on medium with half-strength MS salts, 8% sucrose and 0.5 mg l-1 BA in darkness at 18 °C. They had near to 30% of dry matter. Microtubers resumed growth in light room at 23 °C after 4–6 months of cold storage.
    Materialart: Digitale Medien
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 55 (1998), S. 151-154 
    ISSN: 1573-5044
    Schlagwort(e): protoplast ; somaclonal variation ; somatic embryo ; tissue culture ; Umbelliferae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Hypocotyl segments of Bupleurum falcatum L. formed embryogenic calluses when cultured on Murashige and Skoog's (MS) medium supplemented with 9.0 μM 2,4-dichlorophenoxyacetic acid (2,4-D). Suspension cultures were initiated by placing calluses into medium with 0.45 μM 2,4-D. Protoplasts were enzymatically isolated from suspension cultures. They were plated at a density of 5 × 104 protoplasts per ml on MS medium supplemented with 9% mannitol, 9.0 μM 2,4-D, 4.4 μM BA, 4.6 μM kinetin, and 0.6% Seaplaque agarose. After four weeks of culture, microcalluses were formed and subsequently transferred to MS solid medium with 18.1 μM 2,4-D. Upon transfer to MS basal medium, microcalluses gave rise to somatic embryos at a frequency of approximately 10%. They subsequently developed into plantlets. The regenerants were successfully transplanted to potting soil and grown to maturity in a greenhouse. The regenerants had the normal chromosome number of 2n=2x=20 and did not show morphological aberrancy.
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  • 60
    ISSN: 1573-5060
    Schlagwort(e): Solanum tuberosum ; potato ; Phytophthora infestans ; late blight ; adventitious regeneration ; somaclonal variation ; tissue culture ; mutation ; maturity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Adventitious regenerants (‘somaclones’) of ‘Bintje’ and their vegetative progeny were screened for field resistance to Phytophthora infestans as follows: the area under the disease progress curve was computed and correlated with resistance rating in ‘Bintje’ and reference varieties. The resistance rating of the somaclones was determined from this relationship. Clones with stable improved field resistance in successive years' trials were detected, however, most of such clones were also maturation mutants. Variation in resistance rating in clone replicates and between years was detected in most clones. The possible basis of the field resistance and reasons for its instability are discussed.
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  • 61
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 56 (1991), S. 269-285 
    ISSN: 1573-5060
    Schlagwort(e): disease resistance ; in vitro selection ; somaclonal variation ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Somaclonal variation, i.e. the variation induced by cell and tissue culture, offers an opportunity to broaden the genetic variation of crops. As a result of somaclonal variation a wide range of plant characteristics can be altered. However, the selection of agronomically important traits, e.g. disease resistance, has many limitations. The efficiency of selection can be increased by the application of in vitro selection procedures. Selection strategies that may be applied to obtain disease resistant somaclonal variants are described. Their merits and limitations, in relation to the efficiency of the procedures, the frequency of disease resistant variants and the genetics of the resistance obtained, are discussed.
    Materialart: Digitale Medien
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  • 62
    ISSN: 1573-5087
    Schlagwort(e): Solanum tuberosum ; tissue culture ; jasmonic acid ; sucrose uptake ; photosynthetic pigments ; xanthophyll cycle
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Potato (Solanum tuberosum L., cv. Sante) plantlets grown from stem node culture on medium supplemented with 90 mM sucrose accumulated lower amounts of photosynthetic pigments per mg dry weight in comparison to those grown on 30 mM sucrose. Addition of 0.1, 1 or 10 µM jasmonic acid (JA) to the medium resulted in a decrease of chlorophylls and carotenoids in the plantlets grown on either sucrose concentration. JA treatment induced de-epoxidation of violaxanthin to antheraxanthin and zeaxanthin only in those plantlets grown on a higher amount of sucrose in which hyperhydric symptoms were observed. The synergistic effect of JA and sucrose was clearly demonstrated in the plantlets grown on 90 mM sucrose and 1 µM JA. This was possibly due to overaccumulation of sucrose, the consequence of the most developed root system, and/or to stimulated water and solute transport by other mechanisms.
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  • 63
    ISSN: 1573-5117
    Schlagwort(e): callus ; cell culture ; domestication ; protoplast ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Cellular biotechnology is a promising application in the propagation and selection of superior strains of seaweeds. Although axenic cultures, organogenetic tissue cultures, vegetative micro-propagation, callus induction and high yields of agar from calli have been described for several species of Gelidium, a number of basic problems remain to be solved. These include standardized methods for obtaining axenic cultures, identification of requirements for organic nutrients, PGR's, cellular disorganization and reorganization, somaclonal variation and somatic incompatibilities. Future progress in seaweed biotechnology will depend on the resolution of many of these problems.
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  • 64
    Digitale Medien
    Digitale Medien
    Springer
    Plant growth regulation 26 (1998), S. 155-163 
    ISSN: 1573-5087
    Schlagwort(e): activated charcoal ; growth regulators ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Activated charcoal is commonly used in tissue culture media. Its addition to culture medium may promote or inhibit in vitro growth, depending on species and tissues used. The effects of activated charcoal may be attributed to establishing a darkened environment; adsorption of undesirable/inhibitory substances; adsorption of growth regulators and other organic compounds, or the release of growth promoting substances present in or adsorbed by activated charcoal.
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  • 65
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 227 (1991), S. 179-185 
    ISSN: 1573-5117
    Schlagwort(e): planarian ; intestine ; endocytosis ; phagocytosis ; tissue culture ; SEM
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Tissue-cultured fragments of the intestine of Dugesia japonica were examined by SEM for formation of pseudopodia in the phagocytic cells. For comparison, parallel experiments in vivo were performed using intact animals under starved and fed conditions. When cultures were incubated with fetal calf serum, individual phagocytic cells formed one or two large cup-like pseudopodia. Cultures incubated with latex beads showed pseudopodia that varied in shape according to the size of the beads and that had multiple folds or funnels. Pseudopodia and the modes of their endocytosis in this planarian, however, are morphologically like those of other phagocytes such as digestive cells of Hydra, rat macrophages, and human neutrophils. Culture in vitro of digestive tissue should be an important tool for studying the digestive physiology of planarians at the cellular level.
    Materialart: Digitale Medien
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  • 66
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 27 (1991), S. 281-287 
    ISSN: 1573-5044
    Schlagwort(e): conifer ; cytokinin ; organogenesis ; Picea glauca ; tissue culture ; white spruce
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Picea glauca (white spruce) zygotic embryos and one-week-old-seedling epicotyl explants were placed on either Woody Plant Medium (WPM) or half-strength Schenk & Hildebrandt (1/2S&H) medium supplemented with varying levels of benzyladenine (BA) (0.1, 1.0, 10, 50, 100 μM), zeatin (10, 50, 100 μM) or thidiazuron (TDZ) (0.01, 0.1 μM). In addition to differences in the number of buds induced at three months on the two media, buds induced on WPM were visually more uniform, less vitrified and elongated faster. On 1/2S&H supplemented with BA, maximum bud induction from embryos occurred on 1.0 μM BA with 0.01 μM TDZ with higher BA concentrations inhibitory to bud induction. In contrast, on WPM there was little difference in the number of buds induced from embryos placed on 10, 50 and 100 μM BA with or without TDZ. One-week-old-seedling epicotyl explants required higher BA levels on 1/2S&H, as bud induction at three months was greatest at 10 μM BA. On WPM, as with the embryos, there were only minor differences in the number of buds induced from epicotyl explants on the various BA levels. Zeatin was more effective at inducing buds than BA with both media. From embryos, bud induction was greatest on 50 or 100 μM zeatin without TDZ and 50 or 100 μM zeatin with or without TDZ on 1/2S&H and WPM respectively. From epicotyl explants on 1/2S&H, there was little difference in the number of buds induced with the zeatin concentrations used, while with WPM, 50 and 100 μM zeatin induced the greatest number of buds. Interestingly, with BA, the epicotyl explants needed a higher level than the embryos for maximal response, while with zeatin, the level was the same for both embryos and epicotyl explants. Long-term (six month) survival was higher on WPM than with 1/2S&H. Additionally, embryos had a higher percentage of genotypes surviving at six-months when compared with epicotyl explants. For overall survival and development of the buds, 50 μM zeatin with 0.01 μM TDZ was the best treatment tested.
    Materialart: Digitale Medien
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  • 67
    Digitale Medien
    Digitale Medien
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    Plant cell, tissue and organ culture 27 (1991), S. 341-348 
    ISSN: 1573-5044
    Schlagwort(e): rooting ; shoot proliferation ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Successful propagation of seedlings and mature trees of Sorbus domestica L. has been achieved by in vitro methods. Multiple shoot formation was obtained by placing shoot apices or nodal segments on a modified Schenck and Hildebrandt medium containing benzyladenine. Regenerated shoots were excised and induced to root on media with auxin. In the best treatments 75–85% of shoots from juvenile material rooted. Rooting capacity of shoots from mature explants was lower (30%) and was not improved by dipping the base of shoots in concentration solutions of indolebutyric or naphthaleneacetic acids. Plantlets were ultimately established in soil.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 68
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 24 (1991), S. 91-95 
    ISSN: 1573-5044
    Schlagwort(e): Agrobacterium ; regeneration ; Ribes nigrum ; tissue culture ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Transformation of the black currant cv. Ben More was achieved by utilising the binary vector system of Agrobacterium tumefaciens. This system involved the inoculation of peeled internodal stem segments with A. tumefaciens strain LBA4404 containing the binary vector PBI121.X with the marker genes Betaglucuronidase (GUS) and neomycin phosphotransferase II (NPTII). Shoot regeneration occurred on nutrient media based on M&S salts. Transformation was confirmed by the fluorogenic assay procedure which determined that the GUS gene had been transferred into the plant material and was being expressed. Concurrent transfer of the NPTII gene into the plant material was also confirmed with a ‘dot blot’ assay on selected GUS positive plantlets.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 69
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 26 (1991), S. 29-34 
    ISSN: 1573-5044
    Schlagwort(e): Carica papaya ; IBA ; papaw ; papaya ; riboflavin ; root initiation ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Varying concentrations of riboflavin were added to a De Fossard et al. (1974) basal medium containing 10 µM IBA and the effect on adventitious root initiation on shoots of Carica papaya L. was studied. Ninety percent root initiation occurred in 11 days when 1 µM riboflavin was added to the culture medium. Smaller rooting percentages were observed and roots emerged more slowly with riboflavin concentrations greater and less than 1 µM. Tissue culture media were maintained at 27°±1°C in either darkness or 12-h photoperiods for 28 days, and concentrations of riboflavin and IBA were measured at regular intervals using HPLC analysis. In a De Fossard et al. (1974) basal medium, riboflavin concentrations (0.1, 1.0, 10.0 µM) decreased rapidly in light and were independent of the presence of IBA. IBA concentration steadily decreased when media was placed in light, and increasing riboflavin concentrations accelerated the reduction of IBA levels. Concentrations of IBA and riboflavin were stable with dark incubation.
    Materialart: Digitale Medien
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  • 70
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 26 (1991), S. 63-70 
    ISSN: 1573-5044
    Schlagwort(e): corm ; cytokinin ; Gladiolus ; paclobutrazol ; sucrose ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Conditions were defined for precocious differentiation and improved growth of corms at the base of gladiolus shoots. Shoots were derived from explants cultured on agar solidified media, and corm regeneration was obtained in subsequent liquid shake cultures. Benzyladenine (BA), at 10-7 M, was found to have a stimulating effect mainly when provided to the shoots prior to manifestation of corm growth. Paclobutrazol and sucrose promoted corm formation when supplemented to the liquid media. Paclobutrazol, at 10 mg l-1, shifted assimilate allocation towards the growing corm. A differential promotion of corm development by sucrose was not observed, and the concentration of sucrose at which the sugar demand for maximal shoot and corm growth is satisfied (60 g l-1) was unaltered by the presence of paclobutrazol. The rate of corm growth on shoots cultured in a liquid medium supplemented with paclobutrazol and a saturating sucrose concentration, was a function of the length of the shoot's leaf blades, and was similar in light and in dark.
    Materialart: Digitale Medien
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  • 71
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 27 (1991), S. 37-43 
    ISSN: 1573-5044
    Schlagwort(e): organogenesis ; plant growth regulators ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The influence of the source of plant material (greenhouse-grown plants or in vitro shoot cultures), the type of tissue explant (shoot-tip, single-node stem segment, whole leaf, leaf strip or half-leaf section) and growth regulator concentration on shoot regeneration from somatic tissue of Rhododendron laetum × aurigeranum was evaluated. No regeneration response was obtained on explants from greenhouse-grown plants. Adventitious shoots were obtained from callus produced at the basal end of shoot-tip and single-node stem segment explants derived from in vitro-grown shoots cultured on Anderson's medium supplemented with 22.8 μM IAA and 73.8 μM 2iP. The greatest percentage of adventitious shoot regeneration (77%) was induced on leaf sections cultured in the presence of 22.8 μM IAA and 147.6 μM 2iP. Plant regeneration was accomplished with minimal callus formation. This technique represents a further step toward gene manipulation of Rhododendron.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 72
    Digitale Medien
    Digitale Medien
    Springer
    Journal of bioenergetics and biomembranes 23 (1991), S. 903-917 
    ISSN: 1573-6881
    Schlagwort(e): Transferrin receptor ; diferric transferrin ; 3T3 cells ; transformation ; iron reduction ; plasma membrane
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Physik
    Notizen: Abstract Transformation of 3T3 cells by SV40 virus changes the properties of the transplasma membrane electron transport activity which can be assayed by reduction of external ferric salts. After 42 h of culture and before the growth rate is maximum, the transformed cells have a much slower rate of ferric reduction. The change in activity is expressed both by change inK m andV max for ferricyanide reduction. The change in activity is not based on surface charge effect or on tight coupling to proton release or on intracellular NADH concentration. With transformation by SV40 virus infection the expression of transferrin receptors increases, which correlates with greater diferric transferrin stimulation of the rate of ferric ammonium citrate reduction in transformed SV40-3T3 cells than in 3T3 cells.
    Materialart: Digitale Medien
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  • 73
    ISSN: 1573-5044
    Schlagwort(e): auxin-like factor ; Brassica juncea ; brown mustard ; organogenesis ; regeneration ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In cotyledon cultures of Brassica juncea, shoots and roots invariable differentiate at the cut end of the petiole. Organogenesis occurred only if the proximal cut end of the petiole was in contact with the medium. In the absence of the petiole, differentiation from the lamina was rare. Hence investigations were carried out to study the influence of the cotyledonary lamina on regeneration of shoots and roots from the petiolar cut end. The lamina tissue was surgically removed from the cotyledon explants at different durations (0–10 days) after culturing them on either root-forming (basal medium) or shoot-forming (basal medium containing 5.0 μM N6-benzyladenine) media. The differentiation of roots or shoots from the petioles was dependent on the presence of the lamina for at least 7 days of culture. Quantitative removal of the laminar tissue had a corresponding negative effect on shoot bud differentiation from the petiole. The nature of the ‘lamina factor’ was found to be auxin-like.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 74
    Digitale Medien
    Digitale Medien
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    Plant cell, tissue and organ culture 24 (1991), S. 79-82 
    ISSN: 1573-5044
    Schlagwort(e): Brassica carinata ; Ethiopia mustard ; hypocotyl ; plant regeneration ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract An efficient tissue culture system for high frequency of plant regeneration from hypocotyl explants of Brassica carinata was developed via manipulation of culture medium and selection of explants. Explants grown on medium containing combinations of 2 mg l-1 BA and 0.01 mg l-1 NAA or 4 mg l-1 kinetin and 0.01 mg l-1 2,4-D regenerated shoots at 100% frequency. High frequency shoot regeneration occurred only from explants originating from 6 to 7-day-old but not younger or older seedlings. Explants showed higher regeneration capacity at the distal end than the proximal end, and the upper segment was more regenerative than the lower segment of hypocotyl. Regenerants were rooted on half-strength growth regulator-free medium, acclimatized and developed into normal, fertile plants.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 75
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 24 (1991), S. 163-172 
    ISSN: 1573-5044
    Schlagwort(e): Agrobacterium rhizogenes ; cryopreservation ; hairy roots ; molecular stability ; secondary metabolites ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Crypopreservation methods were firstly developed for root-tips from hairy root cultures of Beta vulgaris, established after transformation by Agrobacterium rhizogenes. The effects of culture age, pre-growth, cryoprotection, freezing rate and post-freeze culture conditions were determined. The resulting freezing protocol was then used to cryopreserve transformed root cultures of Nicotiana rustica. Both species were viable after freezing (ca. 80%), according to fluorescein diacetate vital staining. However, on average the regeneration of proliferating roots from surviving root-tips was low (〈20%). Growth rates, secondary metabolite production and T-DNA structure of a number of hairy root lines were examined and found to be unchanged after cryopreservation.
    Materialart: Digitale Medien
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  • 76
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 24 (1991), S. 193-198 
    ISSN: 1573-5044
    Schlagwort(e): Limnanthes alba ; meadowfoam ; somatic embryogenesis ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Developing embryos from immature seeds were excised and cultured. Optimal proliferation of differentiated secondary embryos occurred on Murashige-Skoog media containing 7% sucrose, 0.1 μM 2,4-D, and 0.1–1.0 μM zeatin. Higher levels of auxins inhibited embryo proliferation. Secondary embryos were subcultured to produce more embryos. The results indicate the feasibility of clonal propagation of meadowfoam.
    Materialart: Digitale Medien
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  • 77
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 25 (1991), S. 117-123 
    ISSN: 1573-5044
    Schlagwort(e): Digitalis thapsi ; plant regeneration ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effects of the auxins 2,4-D, NAA and IAA either alone or in combination with kinetin or BA were investigated to assess the morphogenetic potential of leaf, root and hypocotyl explants of Digitalis thapsi. Calluses were obtained from the three explants in basal medium without the addition of growth regulators and in leaves, the calluses formed roots. Application of 2,4-D, NAA or BA increased callus formation. The presence of NAA induced root formation and that of BA induced shoot formation via callus interphase. Indole-3-acetic acid alone only induced the generation of roots in the hypocotyl callus. Kinetin was ineffective in all the explants tested. Combinations of NAA with kinetin or BA were more effective in inducing organogenesis in leaf explants. Optimum responses were obtained in hypocotyl and root explants by using IAA in combination with BA, the highest rate of shoot regeneration being observed in hypocotyl explants. Rooting of the differentiated shoots was readily achieved in media without growth regulators. Regenerated plantlets were transferred to soil and grew with a survival rate of 70%.
    Materialart: Digitale Medien
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  • 78
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 25 (1991), S. 199-208 
    ISSN: 1573-5044
    Schlagwort(e): Agrobacterium tumefaciens ; cocultivation ; enzymatic digestion ; tissue culture ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Agrobacterium attached to wheat embryos in vitro. This attachment was plasmid independent, and occurred on both wounded and unwounded cell surfaces. The pattern of attachment clearly demonstrated that bacterial attachment to cereal cells follows the same trends observed for dicotyledonous plants. During the inoculation period the bacterial cells attach to the plant cell walls either with lateral or polar orientation. Wounding (mechanical or enzymatic) preferentially promoted adherence of the bacteria at the wound site, however, attachment was not wound dependent.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 79
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 25 (1991), S. 209-218 
    ISSN: 1573-5044
    Schlagwort(e): Agrobacterium tumefaciens ; cocultivation ; tissue culture ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract DNA can be transferred by Agrobacterium tumefaciens to wheat, albeit at very low frequencies. Transfer of agrobacterial DNA occurred in cultures where the embryos had been subjected to partial enzymatic digestion prior to cocultivation with the bacteria. It is unclear whether this is by the normal process mediated by the Ti virulence genes and the border repeats of the T-DNA. The Southern hybridization patterns indicate that in one cell line the T-DNA had undergone extensive rearrangements, and might indicate that the process of T-DNA transfer and integration might differ in the case of cereals. This could suggest the method of transfer and ultimately the expression of these genes in cereal cells may be different to that observed in other monocotyledonous and dicotyledonous species.
    Materialart: Digitale Medien
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  • 80
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 26 (1991), S. 1-6 
    ISSN: 1573-5044
    Schlagwort(e): chilling ; lignin synthesis ; shoot multiplication ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The interaction between gel concentration, cytokinin levels and temperature in vitrification of Olearia microdisca in vitro has been investigated. Vitrified plants displayed tissue hypertrophy and reduced lignification. Cytokinin in the medium was essential for vitrification. Increasing gel concentration or reducing temperature reduced the vitrification in the presence of 20 µM BA. The observed responses were consistent with indirect effects on BA uptake. Alternatively an indirect effect of BA on shoot multiplication rate and hence on lignification of cell walls may be involved.
    Materialart: Digitale Medien
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  • 81
    ISSN: 1573-0603
    Schlagwort(e): Epstein-Barr virus ; feeder layer ; B-lymphocytes ; transformation ; human cell lines
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Methods are described for the efficient transformation of fresh or cryopreserved human B lymphocytes to produce continuous, lymphoblastic cell lines. Lymphocytes are separated from whole blood by centrifugation through Ficoll. They are transformed by exposure to Epstein-Barr Virus (EBV) obtained as a supernatant from ATCC. CRL 1612 (B95-8) cells. Virus production is verified in advance by immunoperoxidase staining after application of a monoclonal antibody to EBV capsid antigen [ATCC.HB 168 (72A1)]. The addition of irradiated feeder cells [ATCC.CCL 17 (MRC-5)] is important to enhance efficiency in lymphoblast culture initiation.
    Materialart: Digitale Medien
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  • 82
    ISSN: 1573-0603
    Schlagwort(e): tissue culture ; uterine epithelial cells ; bovine ; monolayer culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Bovine epithelial cells were obtained for culture from the uterine endometrium of adult, cyclic cattle. Using the procedures described herein, cell-specific monolayers of uterine epithelial cells developed rapidly in culture and maintained a good level of viability for seven to eight subcultures. In addition, frozen-thawed uterine epithelial cells also maintained a respectable level of viability during postthaw subculture. Patterns of cell growth for uterine epithelial cells were determined by a growth curve. A growth curve of fresh epithelial cells over an 8-day interval revealed a short lag phase (24 h) followed by a log growth phase for 5 days and then a stationary phase starting on Days 6 or 7 of incubation. This method for isolation and culture of uterine epithelial cells provides a potential model for evaluating uterine epithelial cell secretory capacity during the estrous cycle. This culture system may offer benefits for in vitro culture of bovine embryos.
    Materialart: Digitale Medien
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  • 83
    Digitale Medien
    Digitale Medien
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    Methods in cell science 13 (1991), S. 265-273 
    ISSN: 1573-0603
    Schlagwort(e): tissue culture ; GMP ; laboratory design ; laboratory operation ; contamination control ; environmental control
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Recommendations are presented for the design and operation of a tissue culture laboratory to reduce microbial contamination of cultures. These recommendations are based on practices currently used in the manufacturing of sterile drug products, certain medical devices, and in vitro diagnostic products. The recommendations depend on qualification and validation of equipment, systems, and procedures and on the control and monitoring of the laboratory environment and procedures.
    Materialart: Digitale Medien
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  • 84
    Digitale Medien
    Digitale Medien
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    Antonie van Leeuwenhoek 73 (1998), S. 147-153 
    ISSN: 1572-9699
    Schlagwort(e): transformation ; plasmid integration ; Phaffia rhodozyma
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Stable red astaxanthin-producing transformants were obtained after genetic transformation of two Phaffia rhodozyma mutants. A yellow mutant, accumulating β-carotene, and an albino mutant, accumulating phytoene, from P. rhodozyma were transformed using a genomic library of wild-type strain UCD 67-385 in the pBluescript vector. Hybridization assays, using the pBluescript DNA as a radioactive probe, indicate integration of vector sequences into the genome of the transformants. Transformants DNA was digested with restriction endonucleases, ligated with T4 DNA ligase and then used to transform E. coli. Ampicillin resistant plasmids, containing 0.1, 0.2, and 2.5 kb DNA inserts of P. rhodozyma, were rescued from the yeast red transformants. The molecular analysis indicate that transformation has occurred by an integration event of donor DNA into the genome of the host strains.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 85
    Digitale Medien
    Digitale Medien
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    Journal of automated reasoning 7 (1991), S. 337-358 
    ISSN: 1573-0670
    Schlagwort(e): Control rules ; transformation ; logic programming
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik
    Notizen: Abstract We present a technique for the compilation of bottom-up and mixed logic derivations into PROLOG-programs. It is obtained as an extension of a program transformation technique called Compiling Control. We illustrate its applications in three different domains: solving numerical problems, integrity checking in deductive databases and theorem proving. The aim is to obtain efficient PROLOG programs for problems in which a non-top-down control is most appropriate.
    Materialart: Digitale Medien
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  • 86
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    Digitale Medien
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    GeoJournal 44 (1998), S. 215-224 
    ISSN: 1572-9893
    Schlagwort(e): cross-border region ; transformation ; regional economic development ; Poland ; Germany
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geographie
    Notizen: Abstract One of the major means to foster European integration is the establishment of border spanning regions (‘Euroregions’). This is particularly important on the Eastern borders of the EU, e.g. in Eastern Germany. There, however, a double transformation to post-socialist society is taking place, both inside and outside the EU. Tensions arise between objectives on local and higher political levels, intensified by totally different economic structures and access to EU funds on both sides of the border. This is particularly true for the case of the emerging Euroregion Viadrina. Problems in preserving old industrialised localities in East Germany (e.g. steel) and attempts to resurrect the urban fair place Frankfurt/Oder, clash with transition in agriculture and consumer industries and with new concepts in tourism development and environmental protection in the Polish border zone. In region building, political, economic and ideological goals compete with each other. Local initiatives and higher political governance may both support and hamper each other. The same holds true for the interdependence of cultural integration and economic development. The paper concludes that regional economic development can only be expected if, via the building of the Euroregion, the interplay of these factors leads to compromise and harmonization between the different parties involved.
    Materialart: Digitale Medien
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  • 87
    Digitale Medien
    Digitale Medien
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    GeoJournal 46 (1998), S. 305-317 
    ISSN: 1572-9893
    Schlagwort(e): agriculture ; border region ; communities ; commuting ; conservation ; Romania ; tourism ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geographie
    Notizen: Abstract A most distinctive feature of the settlement pattern of the Brasov area is the extreme dispersal of mixed farming encountered in the western extreme of the county to the north and south of Zarnesti: the Bran and Poiana Marului areas. Here a system of peasant subsistence farming developed in a political borderland between the Habsburg and Ottoman Empires. Despite feudal pressures, the peasantry took all available opportunities to extend their independence including elaborate transhumance systems. And after seeing transfrontier commerce as a source of plunder, in the tradition of Balkan highway robbery within relatively unregulated spaces, the peasantry has profited through employment in factories, particularly during the communist period. However, the current recession in manufacturing is throwing the rural population back on limited land resources. Although farming assumes an important subsistence role which contributes to stability, the long-term survival of these communities will depend on new sources of income. Rural tourism has considerable potential and a promising start has been made in Bran. There are, however, constraints on the further development of the business and great attention will have to be given to the conservation of the environment in both the Bucegi Mountains and the Piatra Craiului where national park status is proposed.
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  • 88
    ISSN: 1572-9893
    Schlagwort(e): chamber of commerce ; economy ; experts ; institutions ; local government ; Romania ; rural ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geographie
    Notizen: Abstract This study evaluates some aspects of the socio-economic transformation of rural Romania with reference to the views of representative organisations (at national, regional and local levels) and other experts. Interviews conducted in ten communes of nine Romanian counties (‘judete’) focus attention on the advantages and disadvantages of system change experienced since 1989; the most important problems and constraints for future socio-economic change; and appropriate policies and perspectives for development in the immediate future. Wherever appropriate the claims of interviewees are substantiated through reference to statistics, drawn in many cases from Chambers of Commerce & Industry (CCI). Local level representatives presented much more negative views on recent change than their national and regional level counterparts, but all agreed on the crucial problem of capital shortage. Thus while specific programmes to assist rural areas are justified, they cannot fully succeed until the national economy is able to grow more rapidly and attract greater foreign investment.
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  • 89
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    GeoJournal 46 (1998), S. 263-269 
    ISSN: 1572-9893
    Schlagwort(e): Croatia ; decentralisation ; diversification ; industry ; innovation ; rural ; transformation ; urbanisation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geographie
    Notizen: Abstract Rural diversification in Croatia is well advanced because many rural families have been able to find work in secondary and tertiary activities without the need to migrate to the towns. Many rural settlements have now attained an urban character although there are regional variations, including a contrast between the continental zone with a relatively high level of commitment to agriculture and the coastal areas, with pronounced ‘deagrarisation’ where the ports and tourist resorts are well developed and the natural resource conditions for agriculture are poor. These variations are examined at the municipality level with reference to two key indicators: the share of nonagricultural population and the share of workers in the total active population. Four categories of socio-economic transformation are recognised: more urbanised, urbanised, less urbanised and rural. The main regional differences between the continental and coastal areas are confirmed with the latter showing a relatively high level of socio-economic transformation through the prominence of more highly urbanised municipalities.
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  • 90
    Digitale Medien
    Digitale Medien
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    New forests 15 (1998), S. 127-138 
    ISSN: 1573-5095
    Schlagwort(e): auxin ; princess tree ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Experiments focused on improving methods for rooting micropropagated Paulownia elongata shoots and enhancing the quality of plants grown from rooted shoots transferred to the greenhouse. Micropropagated shoots rooted on basal Murashige and Skoog medium, but inclusion of 0.2 mg/l naphthaleneacetic acid and 0.4 mg/l indole-3-butyric acid during a 10-day rooting treatment resulted in a shorter rooting time, a greater number of roots per shoot, and shorter roots that were more easily manipulated during transfer to the greenhouse. Shoots with a greater initial height had greater rooting success than short shoots. Shoots from 1.1 to 2.0 cm in height were preferable to taller shoots because: (1) less time is required to produce them, (2) their smaller leaf size makes them easier to handle, (3) they root with about the same frequency, (4) rooted shoots are more easily transferred to the greenhouse, and (5) once in the greenhouse they attain a height that is indistinguishable from shoots that were classified as very tall at the start of the rooting process. Inclusion of sucrose in the rooting medium promoted rooting as compared to shoots rooted without sucrose. Of the fertilizer treatments applied to plants newly transferred to the greenhouse, 17-17-17 (N-P-K) and 0-44-0 each applied at 1 g/l with each watering resulted in the highest portion of plant fresh mass allocated to roots (49%).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 91
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 53 (1998), S. 221-225 
    ISSN: 1573-5044
    Schlagwort(e): ethylene ; micropropagation ; oxygen ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Efficient micropropagation of papaya (Carica papaya L.) has become crucial for multiplication of specific sex types of papaya or transgenic lines resistant to virus infection. In this study, aeration at different intervals with a 0.02 μm filter disc in the closure of culture flasks ensured exchange of gas components. The effect of aeration on development of multibuds to multishoots was investigated. Multibuds grown in culture flasks after one-week without aeration followed by a two-week aeration treatment caused a 41% increase in the number of shoots ≥0.5 cm, 42% increase in leaf expansion, and 17% increase in leaf numbers in comparison with unaerated materials. Ethylene and oxygen concentrations in the culture flasks were measured by gas chromatography and oxygen electrode at weekly intervals during the culture period. Oxygen concentrations were slightly different between aerated and unaerated culture flasks. Ethylene in the unaerated flask reached the highest level (0.11 ppm) 2 weeks after the treatment, while accumulation of ethylene in the aerated flasks was not detected. The multishoots grown for 3 weeks without aeration showed growth retardation on leaves and epinasty on petioles.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 92
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 53 (1998), S. 189-196 
    ISSN: 1573-5044
    Schlagwort(e): calorimetry ; metabolic heat rate ; micropropagation ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract This study characterizes a potential model system for the use of calorespirometry to make rapid and non-destructive estimations of in vitro responses of carnation. Determinations of steady-state heat production rates, long-term heat rate stability, base trap limitations, effects of wounding and the predictions of dry mass accumulation using calorespirometric measurements were undertaken. Carnation shoot tips grown in vitro provide stable and adequately large heat production rates that vary linearly depending on dry mass. Wounding of tissues had inconsistent effects on RCO 2, but greatly increased q. Linear relationships were found between dry mass and both q and RCO 2.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 93
    ISSN: 1573-5044
    Schlagwort(e): afforestation ; Glomus fasciculatum ; Glomus macrocarpum ; tissue culture ; transplantation shock
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Investigations were carried out to achieve cent per cent transplantation success of micropropagated Leucaena leucocephala (a fast growing multipurpose leguminous tree species) plantlets using two vesicular arbuscular mycorrhizal fungi, Glomus fasciculatum and Glomus macrocarpum. Plantlets were obtained by rooting the shoots [obtained through; hypocotyl callus in presence of 10-5M BAP + 10-6M NAA; and axillary bud sprouting from cotyledonary and other nodes in presence of 10-5M BAP, on Gamborg's B5 medium], on half strength B5 medium supplemented with 5×10-6M IBA. Subsequent to the nodulation of their roots with Rhizobium (strain PRGL 001)in soilrite, these plantlets were tranferred to sterilized garden soil by laying inoculum of either Glomus fasciculatum or Glomus macrocarpum around their roots. Only 20% of the plantlets survived in soils lacking VAM fungus. In contrast, cent per cent of the plantlets of Leucaena leucocephala established very well and showed good growth in VAM inoculated soil. Roots of the later plantlets showed presence of both external and internal hyphae with well formed arbuscules and vesicles confirming the establishment of good mycorrhizal association. These studies convincingly demonstrate that the mycorrhizal association help in successful establishment of tissue culture raised plantlets of Leucaena leucocephala in the field conditions by alleviating the transplantation shock.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 94
    ISSN: 1573-5044
    Schlagwort(e): Fragaria × ananassa ; plant transformation ; regeneration ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effects of growth regulator balance and culture conditions on the morphogenetic response of leaf disks from greenhouse grown plants of the strawberry cultivar Chandler, have been studied. Best results were obtained in the presence of 2.46 μM IBA and 8.88 μM BA, where 47% of the cultures regenerated after 16 weeks with 2.9 shoot colonies per regenerating leaf disk. Optimum incubation conditions included two weeks in the dark with subsequent transfer to light (40 μmol m-2 s-1, 16 h). The regeneration protocol was also valuable when leaf disks from in vitro grown plants were used as explants. Transformation was attempted using Agrobacterium tumefaciens carrying the plasmid pBI121. Leaf disks from in vitro cultures proliferating in the presence of 2.21 μM kinetin were best explants for transformation. A 4.22% of inoculated explants showed kanamycin resistance after 16 weeks in a medium containing 25 mg l-1 of this antibiotic. The transgenic nature of several shoots was also confirmed by the GUS assay and PCR analysis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 95
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 55 (1998), S. 175-181 
    ISSN: 1573-5044
    Schlagwort(e): Conifer ; transformation ; virulence genes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract As a preliminary step in efforts to develop a successful protocol for Agrobacterium-mediated transformation of cotyledonary explants of Pinus pinea L. embryos, we tested the ability of embrionary exudates of this species to induce the expression of the virulence genes virA, virB, virC, virD, virE and virG in Agrobacterium tumefaciens containing vir: lacZ fusion constructs. The results obtained in the vir induction assay indicated the absence of bactericidal or bacteriostatic plant compounds affecting A. tumefaciens growth, and showed that cotyledonary and embrionary exudates of P. pinea are able to induce all virulence genes studied, except virG. The data suggest that A. tumefaciens can be used for gene transfer into this important forest and fruit species.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 96
    ISSN: 1573-5060
    Schlagwort(e): diallel analysis ; general combining ability ; β-glucuronidase ; specific combining ability ; transgenes ; epistatic gene silencing
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A full diallel analysis is a tool for selection in plant breeding that has been subject to many discussions and controversies regarding its interpretation and merits. The analysis of well-defined transgenes by such an approach permits assessment of the value of diallel analyses. The performance of the Eberhart/Gardner diallel approach is analysed for the β-glucuronidase (GUS) activity of six well-defined, homozygous one-locus tobacco (Nicotiana tabacum L.) transgenic lines, each carrying differently located alleles of the GUS gene, and the nulliplex wild type. Tobacco is an inbreeding plant species, therefore all these lines are fully isogenic apart from the T-DNA insertion. The analysis shows that additivity of GUS gene activity as well as epistatic gene silencing translate well in the diallel parameters of general combining ability (GCA) and specific combining ability (SCA) or more detailed versions thereof, when compared to a parsimonious model based on the precise genetic constitution of the transgenic plants lines used as parents. The tobacco line with the highest GUS activity also has the highest GCA, demonstrating that an evaluation of parental phenotype would be sufficient for determining breeding potential. In case of the epistatic gene silencing, however, there is no positive correlation between GCA and parental performance, the reduction in GUS activity is more severe than is to be expected on the basis of parental performance.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 97
    ISSN: 1573-5060
    Schlagwort(e): Malus ; somaclonal variation ; tissue culture ; in vitro
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract To assess somaclonal variation, ‘Gala’ and ‘Royal Gala’ trees obtained via axillary and adventitious bud formation were compared ex vitro to conventionally grafted trees. In general, tissue culture-derived trees were relatively erect in comparison to grafted trees. Their branch angles were narrower than those of grafted trees. All trees that flowered had pink blossoms. There were no obvious differences in flowering time or in floral morphology. Most of the seven-year-old grafted control trees produced more fruits than either axillary or regenerated trees. Although there were differences in the range of fruit color between ‘Royal Gala’ and ‘Gala’ apples in both the control and tissue culture-derived plants (the fruits of ‘Royal Gala’ were darker red and more striped than those of ‘Gala’) and also in the degree of pigmentation from tree-to-tree, none of the variation exceeded that observed among apples harvested from an individual ‘Royal Gala’ or ‘Gala’ control tree for either the plants derived from axillary buds or adventitiously. Since both ‘Gala’ and ‘Royal Gala’ axillary buds showed very little somaclonal variation for the morphological and reproductive traits we studied, it appears that tissue culture may be a useful way to propagate these cultivars.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 98
    ISSN: 1573-5060
    Schlagwort(e): Fusarium subglutinans ; callus ; tissue culture ; culture filtrate ; resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Two pineapple varieties differing in resistance to fusariose were examined for the phytotoxic effect of Fusarium subglutinans culture filtrate. The cultivars were Perolera (more resistant to pathovars of Fusarium subglutinans) and Smooth Cayenne (more susceptible). The phytotoxic effect of culture filtrate was assessed in tissue culture pineapple plantlets (by electrolyte leakage and placing the culture filtrate on wound leaf segments) and callus (inhibition of growth). Smooth Cayenne proved to be the most sensitive cultivar in each test, whereas Perolera showed resistance to the culture filtrate and its callus grew in the presence of high concentrations of culture filtrate that were completely toxic to Smooth Cayenne. These results show that plants can display cellular resistance to the culture filtrate.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 99
    ISSN: 1573-5044
    Schlagwort(e): culture medium ; legume trees ; microcutting ; morphogenesis ; rooting ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The influence of five different macronutrient formulations and various growth regulators on micropropagation of single node explants from Acacia mangium and Paraserianthes falcataria seedlings was examined after 4 weeks and 8 weeks in vitro. The experiment was repeated 4 months later. On media lacking growth regulators, growth and development were significantly influenced by the different macronutrient solutions tested, although morphogenic responses could vary according to the species. For instance, P. falcataria displayed a greater ability for adventitious rooting than A. mangium. Overall, Knop macronutrient solution induced the weakest responses. Explant responsiveness was significantly influenced by the addition of 2.2 or 4.4 μM 6-benzyladenine combined with either 1.4 or 2.3 μM kinetin, 1.5 or 2.5 μM indolebutyric acid or 1.6 or 2.7 μM naphthaleneacetic acid. The various combinations of growth regulators tested were shown to inhibit the rooting ability of the explants, while stimulating the production of basal shoots for both species, and of axillary shoots only for A. mangium. In such experimental conditions, A. mangium displayed overall a greater potential for micropropagation than P. falcataria.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 100
    ISSN: 1573-5044
    Schlagwort(e): dwarf cultivars ; dwarfism ; selection ; tissue culture ; tolerance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Microcuttings of three strains of ‘McIntosh’ apple that varied in their growth habit under field conditions were tested for their tolerance to three cytokinins (BA, kinetin, and 2iP) and one cytokinin-like compound (TDZ) in vitro. The three strains were ‘McIntosh’ (standard), ‘Macspur’ (intermediate) and ‘Wijcik’ (dwarf). For each cytokinin ‘Wijcik’ was more tolerant of high cytokinin levels than either ‘Macspur‘, which showed an intermediate tolerance, or ‘McIntosh’ which did not tolerate (died) high levels of cytokinins. These results show that ‘Wijcik’ exhibits multiple cytokinin tolerance in vitro. The relationship between growth habit and BA tolerance has been reported earlier. The present study demonstrates that cytokinins can be used to differentiate among growth types in apple.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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