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  • 1975-1979  (2)
  • 1965-1969
  • 1915-1919
  • Differentiation of cytotrophoblast  (1)
  • Pteridium aquilinum  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 4 (1978), S. 117-138 
    ISSN: 1573-1561
    Keywords: Bracken fern ; Pteridium aquilinum ; phytoecdysteroids ; insect feeding deterrents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Analysis of green bracken fronds collected during July, August, and October, 1975, for phytoecdysteroids showed that these compounds occur in only trace amounts (0.25–0.53 μg/kg fresh weight [FW]). The effect of ecdysteroids on the feeding behavior of seven species of insect showed that four species were deterred at ecdysteroid concentrations at or above 60 mg/kg FW diet; one species of insect at 6 mg/kg or above, and two species which were not affected at the higher concentrations. It was concluded that the levels of phytoecdysteroids in bracken would not deter insects from feeding on the plant. The previously published data relevant to the possible role of phytoecdysteroids as defense compounds are also discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 178 (1977), S. 411-419 
    ISSN: 1432-0878
    Keywords: Human placenta ; Lysosomes ; Differentiation of cytotrophoblast ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An ultrastructural and ultrahistochemical study of first trimester human placentae confirms previous reports that the cytotrophoblastic cells show a spectrum of differentiation, that dissolution of the limiting membrane of the cytotrophoblastic cells occurs and that fragments of free membrane can be found in the syncytiotrophoblast. There is an aggregation of primary lysosomes in the region of approximation of the cytotrophoblast to the syncytiotrophoblast, free lysosomal enzymes are found in the space between the two trophoblastic components, secondary lysosomes have been noted in the vicinity of fragmenting cytotrophoblastic cell membrane and the incorporation of a segment of free membrane into a vesicular structure has been noted. It is suggested that placental lysosomes mediate the dissolution of the cytotrophoblastic cell membranes that is a necessary prerequisite for their full differentiation into syncytiotrophoblast and it is further suggested that one of the principal roles of placental lysosomes is in the structural refashioning of the organ that occurs during the first trimester.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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