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  • scanning electron microscopy  (3)
  • Berberis  (1)
  • Cytokine-induced neutrophil chemoattractant  (1)
Materialart
Erscheinungszeitraum
Schlagwörter
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Planta 167 (1986), S. 310-320 
    ISSN: 1432-2048
    Schlagwort(e): Alkaloid (compartmentation, formation) ; Cell culture (enzyme compartmentation) ; Berberis ; Isoquinoline alkaloid ; Vesicle (alkaloid formation)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Out of the eight enzymes involved in the biosynthesis of the isoquinoline alkaloid berberine, at least, two enzymes, berberine bridge enzyme and (S)-tetrahydroprotoberberine oxidase, are exclusively located in a vesicle with a specific gravity of ϱ=1.14 g·cm−3 as shown by direct enzymatic assay as well as immunoelectrophoresis. Electronmicroscopic examination of the enzyme-containing particulate preparation from Berberis wilsoniae var. subcaulialata cultured cells demonstrated that it is composed mainly of membranous vesicles. The protein composition of this preparation reveals the presence of only about 20 separable proteins, of which two major ones are berberine bridge enzyme and (S)-tetrahydroprotoberberine oxidase. Incubation of these vesicles with the substrate (S)-reticuline in the presence and absence of S-adenosyl-l-methionine leads to the formation of a red product which was identified as dehydroscoulerine. If the cytoplasmic enzyme S-adenosyl-l-methionine:(S)-scoulerine-9-O-methyltransferase is added to the vesicle preparation in the presence of (S)-reticuline and S-adenosyl-l-methionine, not dehydroscoulerine but columbamine, the immediate precursor of berberine is formed. Some of the quaternary alkaloids are located inside the vesicles; fusion of these vesicles leads to vacuoles containing the quaternary alkaloids. These vesicles are the first highly specific and unique compartment serving only alkaloid biosynthesis; they are found in members of four different plant families and in cell cultures as well as in differentiated tissue.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Chromosome research 2 (1994), S. 411-415 
    ISSN: 1573-6849
    Schlagwort(e): plant chromosomes ; preparation technique ; scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A highly reproducible technique to prepare plant chromosomes for high-resolution field emission scanning electron microscopy is presented. The procedure allows the production of relatively high numbers of chromosome spreads that can be viewed at high resolution, showing structural details below 10 nm. This preparation technique is not restricted to metaphase chromosomes, but also allows the observation of plant chromosomes during all stages of the cell cycle.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Langenbeck's archives of surgery 384 (1999), S. 216-221 
    ISSN: 1435-2451
    Schlagwort(e): Key words Recombinant granulocyte colony-stimulating factor ; Inducible nitric oxide synthase ; Intercellular adhesion molecule-1 ; Cytokine-induced neutrophil chemoattractant ; Hepatocytes ; Hepatic nonparenchymal cells ; mRNA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Introduction: We have recently demonstrated that recombinant granulocyte colony-stimulating factor (rG-CSF) modulates lipopolysaccharide (LPS)-induced Kupffer cell activation with subsequent reduction in hepatic leukocyte-endothelial cell interaction, thereby achieving protection against microcirculatory perfusion failure and hepatic dysfunction. To further clarify the underlying mechanisms, rG-CSF treated liver cells were tested for the LPS-induced gene expression of cytokine-induced neutrophil chemoattractant (CINC) and intercellular adhesion molecule-1 (ICAM-1) as potential chemotactic and leukocyte-recruiting factors and for the gene expression of inducible nitric oxide synthase (NOS II) as potential modulator of leukocyte adherence. Methods: Using a collagenase, DNAse/ pronase digestion technique, hepatic parenchymal and nonparenchymal cell fractions were obtained from livers of in vivo rG-CSF pretreated Sprague-Dawley rats 2 h after LPS exposure. mRNA transcripts were assessed using northern blot analysis. Results: In control livers only ICAM-1 mRNA was found constitutively expressed in hepatic nonparenchymal cells. rG-CSF per se did not affect NOS II, CINC, or ICAM-1 expression in hepatic liver cells, while LPS induced a marked expression of NOS II, CINC, and ICAM-1 in nonparenchymal cells and, to a lesser extent, in hepatocytes. Administration of rG-CSF prior to LPS exposure tended to increase NOS II, CINC, and ICAM-1 mRNA transcripts in hepatocytes. In nonparenchymal cells, however, NOS II and CINC were found reduced in rG-CSF pretreated animals upon LPS exposure. Conclusions: The present data show a strikingly different cell type specific pattern of inflammatory response genes in rG-CSF-modulated hepatic endotoxemia. Reduced expression of NOS II, in particular of CINC, in the nonparenchymal cell fraction may contribute to the reduced leukocyte adherence and thus attenuation of cell-dependent tissue injury in rG-CSF pretreated endotoxemic animals.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Chromosome research 3 (1995), S. 368-374 
    ISSN: 1573-6849
    Schlagwort(e): chromosomes ; DNA staining ; EDX ; platinum blue ; scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We describe a DNA-specific staining procedure, using a blue platinum organic dye, which allows DNA imaging of chromosomes by detection of back-scattered electrons in the scanning electron microscope. DNA distribution is visualized within chromosomal details of the centromeric and satellite regions, or in interphase chromatin, with high-resolution (10–15 nm) for comparison with the corresponding secondary electron image representing DNA plus protein.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Chromosome research 4 (1996), S. 288-294 
    ISSN: 1573-6849
    Schlagwort(e): cell cycle ; plant chromosome ; scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The surface structure of mitotic barley and rye chromosomes was studied by high-resolution scanning electron microscopy. Chromosomes with various degrees of chromatin condensation were prepared from untreated meristematic tissue of root tips. At lower magnifications the highly condensed chromosomes in metaphase and anaphase showed a compact structure with a smooth surface. The condensation starts from the centromeric region and the chromatics are often discernible in the still uncondensed telomeric region. Decondensation begins at the telomeric region during telophase. Parallel arrangement of fibres is a characteristic feature predominately seen in prophase and telophase chromosomes. Chromatin structures that resemble tiles on a roof or braided strands were often observed. Prophase and telophase chromosomes are particularly suitable for further studies of chromatin arrangement and organization in plant chromosomes.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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