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  • 1995-1999  (2)
  • PAM fluorescence  (1)
  • Triterpene glycosides  (1)
Materialart
Erscheinungszeitraum
  • 1995-1999  (2)
Jahr
  • 1
    ISSN: 1573-5052
    Schlagwort(e): oxygen measurements ; PAM fluorescence ; photoinhibition ; Porphyra ; rhodophyta ; ultraviolet radiation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Photosynthetic oxygen production and PAM fluorescence measurements were used to follow photoinhibition in the red macroalga Porphyra umbilicalis. Exposure to simulated solar radiation caused inhibition of the effective photosynthetic quantum yield from which the thalli partially recovered in the shade in subsequent hours. There were no significant differences between samples exposed to unfiltered radiation and those exposed to radiation from which increasing portions of UV radiation had been removed indicating that the thalli are well adapted to current levels of solar PAR and UV radiation. This notion was supported by the finding of high concentrations of UV screening pigments which were even enhanced by exposure to increased UV radiation. However, when exposed to (only) UV radiation about 50% higher than that encountered by the organisms in their natural habitat, the photosynthetic yield decreased slowly and did not show any recovery even when the degree of inhibition did not exceed 10%.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 0947-3440
    Schlagwort(e): Carbohydrates ; Cucumaria japonica ; Cucumaria miniata ; Sea cucumbers ; Cucumariosides ; Triterpene glycosides ; Antitumor activity ; Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: New cytotoxic triterpene oligoglycoside disulfates, cucumariosides A3 (1) and A6-2 (2), have been isolated from the sea cucumber Cucumaria japonica. The trisulfated cucumarioside A7-3 (4) was found to be the major component in the glycoside fraction of Cucumaria miniata. The structures were assigned on the basis of extensive spectral data (NMR and MS), selective solvolysis of desulfated derivative 3 and other chemical evidence. The presence or absence of a carbonyl group at C-16 of the aglycone and of sulfate groups at C-6 of the glucose and 3-O-methylglucose units are interpreted in terms of the functional evolution of sea cucumbers in order to improve their defensive system. Both (1) and (2) are cytotoxic in vitro at IC50 = 1 μg/ml against a selection of five human and mice tumoral cell lines.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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