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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Plant growth regulation 18 (1996), S. 71-77 
    ISSN: 1573-5087
    Keywords: Arabidopsis ; ethylene ; ethylene binding protein ; signal transduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A review of work carried out on ethylene binding in higher plants is presented. The use of radio-labelled displacement assays has identified specific 14C-ethylene binding in all tissues so far studied. virtually all higher plants studied contain at least two classes of ethylene binding site, one of which fully associates and dissociates in about 2 h and a class of sites that takes up to 20 h to become fully saturated. Although the types of site differ in their rate constants of association they have similar and high affinities for ethylene. A series of Arabidopsis thaliana mutants shown to vary in sensitivity to ethylene have been analysed for 14C-ethylene binding. One mutant, eti 5, which was shown to be unaffected by ethylene concentrations of up to 10,000 μL L−1 was also shown to exhibit reduced binding. In vivo and in vitro studies on pea have shown that ethylene binding can be detected in this tissue. In vitro studies have shown that both membrane and cytosolic fractions contain measurable amounts of ethylene binding. Interestingly, cytosolic ethylene binding consisted only of the fast associating/dissociating type. Developing cotyledons of Phaseolus vulgaris contain a higher concentration of ethylene binding sites that other tissues and only contain the slow dissociating component. These facets have allowed the purification of ethylene binding protein(s) (EBP) from this tissue. The proteins which bind ethylene can be resolved into two bands of 26 and 28 kDa on semi-denaturing PAGE and the proteins appear to be single entities on a 2-D gels. Data will be presented which indicate a possible role for heterotrimetric G-proteins in the early stages of the ethylene signal transduction pathway.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-5087
    Keywords: Vicia faba ; ethylene ; ethylene oxide ; waterlogging ; metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The ability of cultivars of Vicia faba L. to metabolize ethylene and the resistance of such cultivars to waterlogging was assessed. Those cultivars showing the highest resistance to waterlogging also had the ability to rapidly metabolize ethylene. It is suggested that a causal relationship may exist between the two processes.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-5087
    Keywords: Arabidopsis ; EBP ; ethylene ; phosphorylation ; receptors ; signal transduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Previous work in our laboratory has demonstrated the existence of high affinity binding sites for the plant growth regulator ethylene. The ethylene binding protein (EBP), from Phaseolus cotyledons, shows many of the characteristics of a functional receptor for ethylene, has been purified on SDS-PAGE and polyclonal antibodies raised in rabbits. Current work involves the investigation of the ethylene transduction signal in a number of ethylene-responsive tissues. In peas, it has been shown that ethylene promotes the phosphorylation of specific proteins of similar molecular weight to the EBP from Phaseolus. Such ethylene-induced phosphorylation can be inhibited by the ethylene antagonist, 2,5-NBD. The antibodies raised to the EBP from Phaseolus have been shown to immunoprecipitate 32P-labelled proteins from membrane protein preparations obtained from pea tissue. Studies on ethylene binding in pea have also shown that the binding of ethylene may be regulated by phosphorylation. Thus, under conditions which promote phosphorylation, binding is inhibited, whereas the reverse is true under conditions which enhance dephosphorylation. Further work is described which examines the effect of protein kinase, protein phosphatase and calcium channel inhibitors on ethylene-induced phosphorylation in peas, together with wild-type (WT) and ethylene insensitive (eti) mutants of Arabidopsis thaliana. The effects of these treatments can be monitored in vivo using the ethylene-induced triple response as a screen. Furthermore, the protein profiles of such treated seedlings can then be compared by labelling protein extracts with 32P and subjecting the samples to SDS-PAGE followed by autoradiography.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 167 (1970), S. 351-369 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A light and electron microscopy study of the structure of the pronephros of the carp, Cyprinus carpio, revealed lymphocytopoiesis, plasmacytopoiesis and erythrocytopoiesis. In addition to the lymphocytes of various sizes, there were transitional cells which had characteristics of both lymphocytes and plasma cells. Some of the plasmacytoid cells had a configuration of cytoplasmic granules suggestive of the Russell body formation described in higher mammalian forms. When India ink particles were injected into the fish intraperitoneally, macrophages containing this marker could be found in the pronephros. The highly vascular structure of this organ emphasized the close association of the cellular elements with the circulating blood. In view of the cell population of the pronephros and its role as a major source of cells producing antibody, it may well represent a primitive prototype of the more advanced mammalian lymph node.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0730-2312
    Keywords: giant cell tumor of bone ; MCP-1 ; TGF-β ; CD68+ ; chemotaxis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Giant cell tumor of bone (GCT) is one of a few neoplasms in which the macrophage/osteoclast precursor cells and osteoclast-like giant cells infiltrate the tumor mass. Monocyte chemoattractant protein 1 (MCP-1) is a potent chemotactic factor specific for monocytes. In search of relevant cytokines that may enhance the recruitment of these reactive cells, we evaluated the localization and regulation of MCP-1 mRNA and protein in GCT by using Northern blot analysis, in situ hybridization and immunohistochemistry. We also determined whether conditioned medium obtained from GCT cultures can recruit human peripheral blood monocytes (CD68+) in an in vitro chemotactic assay. Using Northern blot analysis, we detected the specific gene transcript for MCP-1 in all GCT samples tested. In situ hybridization and immunohistochemistry revealed that both MCP-1 gene transcript and protein were consistently present in the cytoplasm of stromal-like tumor cells of GCT. Treatment of mononuclear cells from GCT at third passage with TGF-β1 for 24 h increased the level of MCP-1 mRNA in a dose-dependent manner, with the maximum effect at 1 ng/ml. Conditioned media from GCT cultures promoted the chemotactic migration of CD68+ peripheral monocytes, an activity which was abolished by the addition of MCP-1 antibody to the conditioned medium. Thus, the results of this study suggest that recruitment of CD68+ macrophage-like cells may be due to the production MCP-1 by stromal-like tumor cells. These CD68+ cells may originate from peripheral blood and could have the capability of further differentiating into osteoclasts in the tumor. J. Cell. Biochem. 70:121-129, 1998. © 1998 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 36 (1993), S. 331-337 
    ISSN: 1040-452X
    Keywords: Ovulation ; Meiotic maturation ; Vixens ; Polar fox ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A total of 15 blue fox vixens aged 1-6 years were mated, 12 once on the first day of estrus and three a second time 48 hr after the first mating, and were killed 4 hr to 8 days following mating. Ova were collected from the oviducts, evaluated by stereomicroscopy, and studied by transmission (TEM; N = 49, 12 vixens) or scanning (SEM, N = 11, three vixens) electron microscopy. At 0-3 days after ovulation, the ova had not cleaved and were at different stages of meiotic maturation. In about one-half of these ova, representing all stages of meiotic maturation, a decondensing sperm head without nuclear envelope or a small pronucleus with partial nuclear envelope was observed. No clear relationship was found between maternal meiotic stage and the stage of paternal pronucleus formation. Sperm tails were never identified in the ooplasm. Cortical granules were released after sperm penetration at early stages of meiotic maturation. Thus the block against polyspermic penetration was activated during maturation of the oocyte. The first two-cell stage appeared 4 days after ovulation (3 days after mating), the first four-cell stage the following day (day 5), and the first eight-cell stage 6 days after ovulation (5 days after mating). In a single vixen mated late (7 days postovulation) two- to four-cell stages appeared the following day (day 8). This indicates that the time required for the first cleavage division decreases with increasing interval from ovulation to mating. The development of a functional nucleolus with fibrillar centers and fibrillar and granular components at the eight-cell stage indicates activation of embryonic RNA synthesis in fox embryos at the six- to eight-cell stage, suggesting that the embryonic genome is activated at this stage. © 1993 Wiley-Liss, Inc.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 95 (1978), S. 287-294 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The potent tumor promoter tetradecanoyl phorbol acetate (TPA) induces early changes in ion movements analogous to those induced by prostaglandins E1 and F2α. Among the earliest changes induced by TPA is a significant increase in 32Pi incorporation within 15 minutes incubation of TPA (10-8-10-6 M) with post-confluent Swiss 3T3 mouse embryonic fibroblasts. Similarly, the active phorbol ester homolog 4-;β-;OH phorbol didecanoate but not the inactive stereoisomeric 4-β-OH phorbol didecanoate stimulated 32Pi incorporation. Also, TPA at the above concentrations stimulated 86Rb+ influx shortly after administration. Both fluxes were ouabain-sensitive in accord with the idea that an early effect of TPA is to alter (Na+ + K+)-ATPase activity. Further, prostaglandin E1 (10-7-10-6 M) and prostaglandin F2α (3 × 10-9-10-7 M) caused a similar stimulation of 86Rb+ and 32Pi uptake. The finding that water-soluble prostaglandin F2α also exhibited stimulatory effects indicated that those hormone-induced responses are not mediated by solvent interactions. The similar responses of phorbol esters and prostaglandin derivatives suggests that phorbol esters and prostaglandin derivatives may act at common membrane sitesThe finding that stimulatory effects were observed at discrete times in the logarithmic phase of growth suggests that the activation of membrane receptors may be cell-cycle dependent.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 16 (1987), S. 47-56 
    ISSN: 0148-7280
    Keywords: spermatozoa ; oocytes ; sperm penetration ; pronuclear stage ; prometaphase stage ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A study of varying combinations of in vitro-aged sperm and in vivo-aged ova at 3 hr intervals from 0-24 hr resulted in failures at different steps of the fertilization process during in vitro fertilization of mouse ova. Significant decreases caused by sperm aging, ova aging, and sperm × ova aging interaction were found in sperm penetration. Pronuclear formation was not affected by sperm aging and was enhanced by ova aging, and there was a significant effect of sperm × ova aging interaction. Sperm aging significantly influenced the prometaphase stage of the fertilization process. Therefore, it is suggested that the detrimental fertilization effects resulting from aging gametes are due to different mechanisms in sperm and ova, that these mechanisms are affected at different times, and that they affect different steps in the fertilization process.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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