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  • 1
    Digitale Medien
    Digitale Medien
    Plant Regeneration from Callus Cultures of Allium trifoliatum subsp. hirsutum and Assessment of Genetic Stability by Isozyme Polymorphism (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Plant breeding 108 (1992), S. 0 
    Details
    ISSN: 1439-0523
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Plant regeneration from callus cultures of Allium trifoliatum subsp. hirsutum fertile accession F-370, was studied as a means for clonal multiplication and germplasm storage of Allium spp. Callus was induced on in votro-cultured basal leaf explants. Best proliferation was obtained on modified BDS medium supplemented with (mg/1): 0.75 picloram, 2.0 benzyl adenine, and 900 casein hydrolysate. Shoot and root organogenesis were obtained in 3 to 5 month old subcultured calli, on BDS or MS medium supplemented with (mg/1): either 0.03 picloram or no auxin, 2 BA or 2-isopentenyladenine, and 900 casein hydrolysate. Direct bulb formation, without shoot elongation, occurred on BDS medium with 10 mg/1 IBA. Under these conditions, callus formation and organogenesis were not obtained with A. trifoliatum subsp. hirsutum var. sterile, a male-sterile genotype. Most regenerants were phenotypically normal, but some abnormal shoots were also observed, i.e. shoots with vitrified or extremely broad leaves. Isozyme polymorphism analysis of seven proteins in the latter regenerants, and in several callus cultures, revealed significant deviation from the original pattern in esterase, 6-phosphogluconate dehydrogenase and superoxide dismutase. No such deviations were detected in normal regenerated plants.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1439-0523.1992.tb00130.x
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  • 2
    Digitale Medien
    Digitale Medien
    Tyrosine Phosphorylation in T-Cell Activation (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Scandinavian journal of immunology 34 (1991), S. 0 
    Details
    ISSN: 1365-3083
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1365-3083.1991.tb01545.x
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  • 3
    Digitale Medien
    Digitale Medien
    Distinct Functions of Vav1 in JNK1 Activation in Jurkat T Cells Versus Non-Haematopoietic Cells (2004)
    Oxford, UK; Malden, USA : Blackwell Science Ltd
    Scandinavian journal of immunology 59 (2004), S. 0 
    Details
    ISSN: 1365-3083
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Vav1, the 95-kDa protein encoded by the vav1 proto-oncogene, is expressed exclusively in haematopoietic cells, where it becomes phosphorylated on tyrosine residues in response to antigen receptor ligation. Vav1 was found to act as a Rac1-specific guanine nucleotide exchange factor and to activate c-Jun N-terminal kinase (JNK1) in vitro and in ectopic expression systems using non-haematopoietic cells. Here, we studied the role of Vav1 in JNK1 activation in T cells versus non-haematopoietic cells. Vav1 overexpression activated JNK1 in COS7 and 293T cells but not in Jurkat T lymphocytes. In contrast, constitutively activated Rac1 efficiently stimulated JNK1 in both cell types under the same conditions. Vav1 did function in T cells because it clearly stimulated the activity of a nuclear factor of activated T-cell reporter plasmid in the same cells. Moreover, Vav1 induction of JNK1 in T cells required coexpression with calcineurin. This cooperation was cell type specific because it was not observed in COS7 or 293T cells. In contrast, Vav1 did not cooperate with calcineurin to activate either extracellular signal-regulated kinase 2 or p38. These findings demonstrate that Vav1 alone is a poor activator of the JNK1 pathway in T cells and emphasize the importance of studying the physiological functions of Vav1 in haematopoietic cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1365-3083.2004.01429.x
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  • 4
    Digitale Medien
    Digitale Medien
    A molecular assessment of homing in the tidepool sculpin (2003)
    Oxford, UK : Blackwell Science Ltd
    Journal of fish biology 62 (2003), S. 0 
    Details
    ISSN: 1095-8649
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Molecular analyses of the mitochondrial genome using restriction fragment length polymorphism (RFLP) were utilized to determine the existence of discrete populations of the tidepool sculpin Oligocottus maculosus from the Barkley Sound region of south-western Vancouver Island, British Columbia. Fifty-five haplotypes were found with three haplotypes making up 38, 16 and 8% of the total sample, respectively. Within individual tidepools, haplotype diversity ranged from 0·30 to 0·92, but haplotypes were typically closely related to one another (nucleotide diversity ranged from 0·0004 to 0·005). The majority of haplotype variation (96–97%) was located within tidepools, but a significant amount of variation (c. 3–4%) was detected among tidepools within single islands. By contrast, there was no significant differentiation among islands or between samples from the Barkley Sound area and a single sample from north-eastern Vancouver Island. The results suggest a low level of population structure within the sample area and that the distribution of haplotypes and haplotype divergences represents a demographic expansion from a single ancestral lineage beginning between 300 000 and 1 000 000 years ago. The low level of population subdivision resolved suggests that despite their ecological specialization in tidepool habitats, tidepool sculpins are influenced by demographic and genetic processes that operate on spatial scales much larger than single tidepools or islands.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1095-8649.2003.00052.x
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  • 5
    Digitale Medien
    Digitale Medien
    Monoterpene glycoside biosynthesis in detached grape berries grown in vitro (1990)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 78 (1990), S. 0 
    Details
    ISSN: 1399-3054
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: A procedure for the culture in vitro of isolated small berries of Vitis vinifera L. cv. Muscat of Alexandria in a Murashige and Skoog basal medium supplemented with N6-benzyladenine and indoleacetic acid is described. Berries developed well in culture during 60 days and tripled in size, but remained green and smaller than normal berries grown in vivo. Some callus formed on the distal end of the berry, and where major skin damage occurred, callus emerged from the cracked berries. In order to examine their biosynthetic competency, berries which were previously cultured in vitro for 60 days were incubated for 48 h in a Murashige and Skoog medium containing a [14C]-labelled water-soluble fraction. This fraction was isolated from grape berries located adjacent to a leaf that had been exposed to gaseous 14CO2 in full sunlight for 5 h. The berries were then recultured for 48 h after which a glycosidic fraction was isolated on a C18 reversed phase column and further separated by thin layer chromatography (TLC). The major labelled band corresponded to the geranyl-β-rutinoside marker, indicating that grape berries have the ability to synthesize monoterpene glycosides. This band also consisted of other monoterpene glycosides as revealed by the gas chromatography-mass spectrometry (GC-MS) analysis of their aglycones (released by enzymatic hydrolysis).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1399-3054.1990.tb08720.x
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  • 6
    Digitale Medien
    Digitale Medien
    Metabolism of [14C]trans-zeatin and [14C]benzyladenine by letached yellow, green and variegated leaves of Schefflera (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 90 (1994), S. 0 
    Details
    ISSN: 1399-3054
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: [8-14C]Benzyladenine (BA) and [8-14C]trans-zeatin (tZ) were fed through the petiole to mature, detached green, yellow and variegated leaves of Schefflera arboricola. Recovery of radioactivity from the plant material ranged between 4.2 and 22.1%. More radioactivity was recovered when tZ was applied compared to BA. Green leaves or the green parts of variegated leaves yielded more radioactivity than the yellow leaf material. BA was metabolized much faster than the endogenous cytokinin tZ. It would appear that while lower amounts of radioactivity were present in yellow leaves, as well as in yellow parts of variegated leaves, the rate of cytokinin metabolism was nevertheless faster. Metabolites that were formed to a greater extent in these yellow parts were the nucleotides of both cytokinins. Currently it is not known whether or not cytokinins influence chlorophyll and other pigment development in chimeric variegated leaves.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1399-3054.1994.tb02194.x
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  • 7
    Digitale Medien
    Digitale Medien
    Liposome-mediated gene delivery into plant cells (1990)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 79 (1990), S. 0 
    Details
    ISSN: 1399-3054
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Liposomes may offer several advantages as vectors for gene delivery into plant cells: (1) enhanced delivery of encapsulated DNA by membrane fusion, (2) protection of nucleic acids from nuclease activity, (3) targeting to specific cells, (4) delivery into a variety of cell types besides protoplasts by entry through plasmodesmata, (5) delivery of intact small organelles. Realization of these advantages calls for the construction of efficient liposomes, for appropriate fusion conditions and for an understanding of the nature of liposome-cell interactions. Various characteristics and techniques of the liposome-cell system are described (mode of delivery, liposome types and composition, and means of promoting delivery of liposome contents). Data of liposome-mediated delivery of various macromolecules into plant cells, with special reference to protoplasts, calli and pollen are reviewed. This includes data obtained by the use of fluorescent probes, radioactive-labelled DNA, viral nucleic acids and expression of plasmid-DNA. Structure and characteristics of plant surfaces and plasmodesmata are discussed with respect to DNA entry. It is suggested that liposome-mediated gene delivery into plant cells, and not only protoplasts, will be advantageous in certain specific tissues and situations.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1399-3054.1990.tb05883.x
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  • 8
    Digitale Medien
    Digitale Medien
    Interactions between growth hormone and dexamethasone in skeletal growth and bone structure of the young mouse (1992)
    Springer
    Calcified tissue international 51 (1992), S. 298-304 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Dexamethasone ; Growth hormone ; Bone mineral content ; Glucocorticoids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The present study investigated the interactions of growth hormone (GH) and glucocorticoid on skeletal growth and bone structure in young mice. The purpose of this study was to examine the possible prevention by GH of the damage inflicted by dexamethasone (Dex) at sites of skeletal growth and ossification. Dex (1 mg/kg) with or without rat GH (rGH) or bovine GH (bGH), 1 mg/kg, was given for 4 weeks, from age 3–7 weeks, to female ICR mice. Tibiae, humerus, and vertebrae were analyzed morphometrically and biochemically. Growth, as determined by the mouse weight, tibial length, and humerus protein content was found to be compromised by dexamethasone. This was prevented by rGH or bGH. The epiphyseal growth plate width, trabecular bone volume, cortical bone width, mineral bone content, and alkaline and acid phosphatase activity were decreased by dexamethasone. These were prevented by rGH or by bGH. The findings of the present study suggest that in the mouse, GH can decrease or even avoid some of the pathological features in growing bones inflicted by high-dose glucocorticoid treatment.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00334491
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  • 9
    Digitale Medien
    Digitale Medien
    Replication of tomato yellow leaf curl virus (TYLCV) DNA in agroinoculated leaf discs from selected tomato genotypes (1993)
    Springer
    Plant molecular biology 22 (1993), S. 995-1005 
    Details
    ISSN: 1573-5028
    Schlagwort(e): agroinfection ; geminivirus ; leaf disc ; Lycopersicon spp. ; tomato ; TYLCV ; whitefly
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The leaf disc agroinoculation system was applied to study tomato yellow leaf curl virus (TYLCV) replication in explants from susceptible and resistant tomato genotypes. This system was also evaluated as a potential selection tool in breeding programmes for TYLCV resistance. Leaf discs were incubated with a head-to-tail dimer of the TYLCV genome cloned into the Ti plasmid ofAgrobacterium tumefaciens. In leaf discs from susceptible cultivars (Lycopersicon esculentum) TYLCV single-stranded genomic DNA and its double-stranded DNA forms appeared within 2–5 days after inoculation. Whiteflies (Bemisia tabaci) efficiently transmitted the TYLCV disease to tomato test plants following acquisition feeding on agroinoculated tomato leaf discs. This indicates that infective viral particles have been produced and have reached the phloem cells of the explant where they can be acquired by the insects. Plants regenerated from agroinfected leaf discs of sensitive tomato cultivars exhibited disease symptoms and contained TYLCV DNA concentrations similar to those present in field-infected tomato plants, indicating that TYLCV can move out from the leaf disc into the regenerating plant. Leaf discs from accessions of the wild tomato species immune to whitefly-mediated inoculation,L. chilense LA1969 andL. hirsutum LA1777, did not support TYLCV DNA replication. Leaf discs from plants tolerant to TYLCV issued from breeding programmes behaved like leaf discs from susceptible cultivars.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00028972
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  • 10
    Digitale Medien
    Digitale Medien
    Enhanced bud regeneration in aspen (Populus tremula L.) roots cultured in liquid media (2000)
    Springer
    Plant cell reports 19 (2000), S. 1146-1154 
    Details
    ISSN: 1432-203X
    Schlagwort(e): Keywords Populus tremula ; Liquid culture ; Root explants ; Thidiazuron ; AbbreviationsANC: Ancymidol ; BA: 6-Benzyladenine ; DPB: Disposable plastic bioreactor ; GA: Gibberellic acid ; GV: Growth value ; IAA: Indole-3-acetic acid ; MSAL: Liquid medium for aspen culture ; MSAS: Semi-solid medium ; NAA : α-Naphtalene acetic acid ; TDZ: Thidiazuron
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  The regeneration potential of excised aspen (Populus tremula L.) roots cultivated in liquid medium, as affected by plant growth regulators and by the position of the isolated root explant on the main root, was investigated. The effect of various levels of benzyladenine (BA) and thidiazuron (TDZ) on bud regeneration in root explants was studied. TDZ in the medium had a marked effect on bud development as compared with BA, inducing a tenfold increase in the number of buds regenerated from various root explants. TDZ enhanced both root and root-borne shoot biomass production but reduced further shoot development and elongation. The position of the isolated root sections on the main root affected regeneration, the proximal sections further away from the root tip producing the highest number of buds per explant in both BA and TDZ treatments. Buds regenerated in close proximity to the site of lateral roots in BA-treated roots, while in TDZ-treated root sections, the buds formed all over the root regardless of the presence of lateral roots. The buds developed from inner cortical and sub-epidermal cell layers, disrupting the epidermis and the inner layers. Root biomass production and growth was greatly enhanced in well-aerated bioreactor culture in the presence of 4.5×10–2 μM TDZ. A high number of the root-borne shoots could be rooted and converted to plantlets. However, while shoots regenerated in a medium with BA rooted well in a growth regulator-free medium, shoots formed in a medium with TDZ required auxin for rooting. Roots cultured in the presence of ancymidol, a gibberellin biosynthesis inhibitor, regenerated non-hyperhydric bud clusters and hyperhydric shoots. These were separated mechanically, subcultured to growth and rooting medium and transplanted ex vitro resulting in phenotypically true-to-type plantlets. The potential of liquid cultures for aspen shoot biomass production from roots is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002990000243
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