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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 90 (1994), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: In suspension cultures of Phytolacca americana, betacyanin accumulation was reduced when cell division was inhibited by treatment with various inhibitors of DNA synthesis or anti-microtubule drugs. Aphidicolin (APC), an inhibitor of DNA synthesis, reduced the incorporation of radioactivity from labeled tyrosine into betacyanin, but the incorporation of radioactivity from labeled 3,4-dihydroxyphenylalanine (DOPA) into betacyanin was not affected by similar treatments. Propyzamide, another anti-microtubule drug, reduced incorporation of radioactivity from tyrosine and DOPA into betacyanin. However, the rate of incorporation from DOPA was higher than that from tyrosine. The results suggest that inhibition of betacyanin accumulation in Phytolacca americana cells by APC and propyzamide is due to suppression of the reaction converting tyrosine to DOPA, which may be closely related to cell division.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 83 (1991), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 2,4-Dichlorophenoxyacetic acid (2,4-D) strongly promoted betacyanin accumulation in suspension cultures of Phytolacca americana L. The betacyanin accumulation attained a maximum at 5 μM 2,4-D, when betacyanin content per cell reached 252% as compared to the control (2,4-D free). 2,4-D elevated the level of free tyrosine, which is the precursor of betacyanin. The addition of 1 mM tyrosine to the medium partially reversed the reduction of betacyanin accumulation caused by the removal of 2,4-D. Tracer experiments using labelled tyrosine showed that 2,4-D activated the biosynthetic pathway from tyrosine to betacyanin. These results indicate that a sufficient supply of tyrosine and the activation of biosynthesis of betacyanin from tyrosine by 2,4-D elevate the level of betacyanin.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0533
    Keywords: Peanut agglutinin ; Prolactin ; Pituitary adenomas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Peanut agglutinin (PNA)-binding sites in human prolactin (PRL)-producing pituitary adenomas were examined by light and electron microscopy together with immunoblot analysis. At the light microscopic level, the majority of the PRL-producing adenoma cells stained positively for PNA in 15 of 20 cases. PNA binding observed in the cytoplasm had a granular appearance. PRL-producing cells adjacent to the adenoma tissue showed negative PNA staining. In normal pituitary glands, the PRL-positive glandular cells were negative for PNA staining. By electron microscopy, reaction products showing PNA-binding sites were detected in some of the secretory granules. Immunoblotting analysis revealed that the PRL bands corresponded to PNA-stained ones with the exception of the main 23-kDa band. PNA-binding sites have some relation to the secretory granules containing glycosylated forms of PRL. These observations suggest that PNA staining can be used as a valuable method to analyze human PRL-producing pituitary adenomas.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0533
    Keywords: Key words Peanut agglutinin ; Prolactin ; Pituitary ; adenomas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Peanut agglutinin (PNA)-binding sites in human prolactin (PRL)-producing pituitary adenomas were examined by light and electron microscopy together with immunoblot analysis. At the light microscopic level, the majority of the PRL-producing adenoma cells stained positively for PNA in 15 of 20 cases. PNA binding observed in the cytoplasm had a granular appearance. PRL-producing cells adjacent to the adenoma tissue showed negative PNA staining. In normal pituitary glands, the PRL-positive glandular cells were negative for PNA staining. By electron microscopy, reaction products showing PNA-binding sites were detected in some of the secretory granules. Immunoblotting analysis revealed that the PRL bands corresponded to PNA-stained ones with the exception of the main 23-kDa band. PNA-binding sites have some relation to the secretory granules containing glycosylated forms of PRL. These observations suggest that PNA staining can be used as a valuable method to analyze human PRL-producing pituitary adenomas.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-041X
    Keywords: Retinol ; Hydrocortisone ; Mucous metaplasia ; Transdifferentiation ; Epidermis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Epidermal mucous metaplasia of cultured skin can be induced by treatment with excess retinol for several days (Fell 1957). In the induction of mucous metaplasia, retinol primarily affects the dermal cells and retinol-pretreated dermis can alter epidermal differentiation towards secretory epithelium (Obinata et al. 1987). In this work, we found that mucous metaplasia could be induced by culturing 13-day-old chick embryonic tarsometatarsal skin in medium containing retinol (20 μM) for only 8–24 h, followed by culture in a chemically defined medium (BGJb) without retinol or serum for 6 days. The application of cycloheximide together with retinol during the first 8 h of culture inhibited epidermal mucous metaplasia during subsequent culture for 6 days in BGJb, indicating that induction of a signal(s) in the dermis by excess retinol requires protein synthesis. However, the presence of 20 nM hydrocortisone (Takata et al. 1981) throughout the culture period did not inhibit retinol-induced epidermal mucous metaplasia of the epidermis. This indicates that a brief treatment of the skin with excess retinol determines the direction of epithelial differentiation toward secretory epithelium; this is a simpler in vitro system for the induction of epidermal mucous metaplasia than those established before.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-0878
    Keywords: Placenta ; Glucose transporter, GLUT1 ; Syncytiotrophoblast ; Placental barrier ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The syncytiotrophoblast covering the surface of the placental villi contains the machinery for the transfer of specific substances between maternal and fetal blood, and also serves as a barrier. Existence of a facilitated-diffusion transporter for glucose in the syncytiotrophoblast has been suggested. Using antibodies to erythrocyte/HepG2-type glucose transporter (GLUT1), one isoform of the facilitated-diffusion glucose transporters, we detected a 50 kD protein in human placenta at term. By use of immunohistochemistry, GLUT1 was found to be abundant in both the syncytiotrophoblast and cytotrophoblast. Endothelial cells of the fetal capillaries also showed positive staining for GLUT1. Electron-microscopic examination revealed that GLUT1 was concentrated at both the microvillous apical plasma membrane and the infolded basal plasma membrane of the syncytiotrophoblast. Plasma membrane of the cytotrophoblast was also positive for GLUT1. GLUT1 at the apical plasma membrane of the syncytiotrophoblast may function for the entry of glucose into its cytoplasm, while GLUT1 at the basal plasma membrane may be essential for the exit of glucose from the cytoplasm into the stroma of the placental villi. Thus, GLUT1 at the plasma membranes of syncytiotrophoblast and endothelial cells may play an important role in the transport of glucose across the placental barrier.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0878
    Keywords: Key words: Galectin ; β-Galactoside-binding lectin ; Human ; Skin ; Immunocytochemistry ; Immunohistochemistry ; Hybridization ; in situ ; Langerhans cell ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The localization of an endogenous 14-kDa β-galactoside-binding lectin (galectin) and its pattern of gene expression were examined in normal human skin by light- and electron microscopy. Under the light microscope, immunostaining of 14-kDa galectin was observed in the cell membrane of cells in the basal and spinous layers of the epidermis. Galectin was also found in the Langerhans cells, as shown by double labeling using anti-14-kDa galectin and anti-CD1a antibodi es. In the dermis, immunostaining for the 14-kDa galectin was positive in the extracellular matrix and fibroblasts. At the electron-microscopic level of resolution, galectin was located primarily along the plasma membrane of keratinocytes, and in both the cytoplasm and nucleus of Langerhans cells in the epidermis, whereas in the dermis it was detected in the extracellular matrix and in both the nucleus and cytoplasm of fibroblasts. The gene expression of 14-kDa galectin was visualized by the HRP-staining me thod following in situ hybridization techniques. The expression was detected in the cytoplasm of cells in the basal and spinous layers of the epidermis; whereas, in the dermis, it was detected in the cytoplasm of fibroblasts. Moreover, SDS-polyacrylamide gel electrophoresis and lectin-blot analysis revealed that this galectin bound to glycoproteins of approximately 17, 62, and 72 kDa in the epidermis and to those of 29, 54, and 220 kDa in the dermis. The present study indicates that 1) normal human skin produces the β-galactoside-binding 14-kDa galectin, and 2) this galectin is located in both the epidermis, particularly in the keratinocytes and Langerhans cells, and in the dermis. These results suggest that galectin is important for cell-cell contact and/or adhesion in the epidermis and for cell-extracellular matrix interaction in the dermis.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-0878
    Keywords: Galectin ; β-Galactoside-binding lectin ; Human ; Skin ; Immunocytochemistry ; Immunohistochemistry ; Hybridization, in situ ; Langerhans cell ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The localization of an endogenous 14-kDa β-galactoside-binding lectin (galectin) and its pattern of gene expression were examined in normal human skin by light- and electron microscopy. Under the light microscope, immunostaining of 14-kDa galectin was observed in the cell membrane of cells in the basal and spinous layers of the epidermis. Galectin was also found in the Langerhans cells, as shown by double labeling using anti-14-kDa galectin and anti-CD1a antibodies. In the dermis, immunostaining for the 14-kDa galectin was positive in the extracellular matrix and fibroblasts. At the electron-microscopic level of resolution, galectin was located primarily along the plasma membrane of keratinocytes, and in both the cytoplasm and nucleus of Langerhans cells in the epidermis, whereas in the dermis it was detected in the extracellular matrix and in both the nucleus and cytoplasm of fibroblasts. The gene expression of 14-kDa galectin was visualized by the HRP-staining method following in situ hybridization techniques. The expression was detected in the cytoplasm of cells in the basal and spinous layers of the epidermis; whereas, in the dermis, it was detected in the cytoplasm of fibroblasts. Moreover, SDS-polyacrylamide gel electrophoresis and lectin-blot analysis revealed that this galectin bound to glycoproteins of approximately 17, 62, and 72 kDa in the epidermis and to those of 29, 54, and 220 kDa in the dermis. The present study indicates that 1) normal human skin produces the β-galactoside-binding 14-kDa galectin, and 2) this galectin is located in both the epidermis, particularly in the keratinocytes and Langerhans cells, and in the dermis. These results suggest that galectin is important for cell-cell contact and/or adhesion in the epidermis and for cell-extracellular matrix interaction in the dermis.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0878
    Keywords: β-Galactoside-binding lectin ; Dermis ; Skin ; Chick embryo ; Immunohistochemistry ; Keratinization ; Mucous metaplasia ; Domestic fowl
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In order to elucidate the roles of metal-independent animal lectins, we systematically investigated changes in expression of 2 kinds of β-galactoside-binding isolectins (MW 14 and 16 kDa) in the dermis of chick embryonic tarsometatarsal skin during the course of development. These lectins were immunohistochemically located at different stages of development both in ovo and in vitro by light and electron microscopy. Light-microscopic observation showed that while positive staining for the 14-kDa lectin was weak at days 8 and 10 it became intense after day 13. In contrast, staining for the 16-kDa lectin was intense at days 8, 10, and 13, but it became weak after day 17 when keratinization of the epidermis was completed. Immuno-electron-microscopic observation revealed that both the 14 and 16-kDa lectins were located on the basement membrane, in the extracellular matrix, and in both the cytoplasm and the nucleus of dermal fibroblasts. Distribution of the 2 isolectins was also examined in cultured skin explants in vitro. The results were almost the same as those obtained in ovo when the skin explant was keratinized in the presence of hydrocortisone. However, in the skin explant where keratinization was prevented and mucous metaplasia was induced by the addition of vitamin A, the distribution of the 14-kDa lectin in the epidermis was significantly affected. These results indicate that (1) the expression of the 2 isolectins is differently regulated in both the dermis and epidermis, (2) the 16-kDa lectin is involved in the early stage of the formation of the dermis and the basement membrane and is replaced by the 14-kDa lectin as keratinization of the epidermis occurs, and (3) the expression of the 2 isolectins in the dermis is not significantly affected by the induction of mucous metaplasia, in contrast to their drastic changes in the epidermis.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-0878
    Keywords: Key words: Placenta – Glucose transporter, GLUT1 – Syncytiotrophoblast – Placental barrier – Gap junction – Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. GLUT1 is an isoform of facilitated-diffusion glucose transporters and has been shown to be abundant in cells of blood-tissue barriers. Using antibodies against GLUT1, we investigated the immunohistochemical localization of GLUT1 in the rat placenta. Rat placenta is of the hemotrichorial type. Three cell layers (from the maternal blood side inward) cytotrophoblast and syncytiotrophoblasts I and II, lie between the maternal and fetal bloodstreams. GLUT1 was abundant along the invaginating plasma membrane facing the cytotrophoblast and the syncytiotrophoblast I. Also, the infolded basal plasma membrane of the syncytiotrophoblast II was rich in GLUT1. Apposing plasma membranes of syncytiotrophoblasts I and II, however, had only a small amount of GLUT1. Numerous gap junctions were seen between syncytiotrophoblasts I and II. Taking into account the localization of GLUT1 and the gap junctions, we suggest a possible major transport route of glucose across the placental barrier, as follows: glucose in the maternal blood passes freely through pores of the cytotrophoblast. Glucose is then transported into the cytoplasm of the syncytiotrophoblast I via GLUT1. Glucose enters the syncytiotrophoblast II through the gap junctions. Finally glucose leaves the syncytiotrophoblast II via GLUT1 and enters the fetal blood through pores of the endothelial cells.
    Type of Medium: Electronic Resource
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