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  • 1
    Electronic Resource
    Electronic Resource
    In vitro secretion of ecdysteroids by Y-organs of the crayfish,Procambarus clarkii (1991)
    Springer
    Cellular and molecular life sciences 47 (1991), S. 948-952 
    Details
    ISSN: 1420-9071
    Keywords: Molting hormone ; ecdysteroids ; 3-dehydroecdysone ; Y-organ ; crayfish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract It was demonstrated that excised Y-organs of the crayfish,Procambarus clarkii, synthesize in vitro 3-dehydroecdysone (3-DHE) as the major product, together with small amounts of ecdysone. Both were identified by immunological and spectroscopic methods. The increase of ecdysteroidogenesis in the Y-organs was accompanied by an increase of the major free ecdysteroid, 20-hydroxyecdysone, in the hemolymph. This suggests a physiological role of 3-DHE, the details of which are still to be elucidated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01929889
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    The biotransformation of tritiated 3-dehydroecdysone by crayfish,Procambarus clarkii (1993)
    Springer
    Cellular and molecular life sciences 49 (1993), S. 1101-1105 
    Details
    ISSN: 1420-9071
    Keywords: Molting hormone ; ecdysteroids ; 3-dehydroecdysone ; 3α-hydroxyecdysteroids ; Y-organ ; crayfish ; Procambarus clarkii
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The injection of 3-dehydroecdysone (3dhE, 5 μ/g), the major ecdysteroid secreted by the Y-organ of crayfishProcambarus clarkii, resulted in apolysis within about 5 days. The hormonal response at the molecular level was investigated by injection of the radio-labeled compound; within 3 h of injection of [3H]3dhE, most radio-isotope was found in the extracted epidermal tissues and identified as ecdysone, 20-hydroxyecdysone (20E), and their 3α-hydroxy epimers. The biotransformation was undoubtedly performed in the peripheral area of the Y-organ. Cleavage of the polar conjugates, using an enzyme fromHelix pomatia, gave all of the above ecdysteroids including 3dhE. It was also found that the biosynthetic site of 3dhE was different from that of ecdysone at the subcellular level of the Y-organ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01929922
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Analysis of hydroxyproline in urine by high-performance liquid chromatography after dabsyl-chloride derivatization (1995)
    Springer
    Amino acids 8 (1995), S. 401-407 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Hydroxyproline ; Dabsyl-chloride ; Urine ; High-performance liquid chromatography ; o-Phthalaldehyde
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In order to analyse hydroxyproline (HYP) in urine, a high-performance liquid chromatographic method was modified. The primary amino groups were blocked with o-phthalaldehyde, and then the secondary amino groups were derivatized with 4-dimethylaminoazobenzene-4′-sulphonyl chloride. In addition, the dabsylated samples were treated with ethyl acetate to obtain a simple elution profile in high-performance liquid chromatography. The dabsyl-HYP and -proline were eluted at 4.7 min and 8.0 min, respectively. The chromatographic analysis was completed within 10 min, including the time needed for reequilibration of the column. Using the present method, the concentration of HYP in urine was determined to 260 ± 6µmol/l.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00806559
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  • 4
    Electronic Resource
    Electronic Resource
    d-Aminoaciduria in mutant mice lackingd-amino-acid oxidase activity (1991)
    Springer
    Amino acids 1 (1991), S. 239-246 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; d-Amino-acid oxidase ; d-Aminoaciduria ; Physiological role ; Mutant mice ; d-Amino acids ; Urine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Urine of mutant ddY/DAO− mice lackingd-amino-acid oxidase activity contained more serine and proline than that of normal ddY/DAO+ mice.d-Amino-acid oxidase treatment of urinary amino acids decreased the serine and proline, suggesting that they containedd-isomers. An HPLC analysis confirmed the presence ofd-serine. Urinary serine and proline contents were not decreased when the ddY/DAO− mice were fed a diet which did not contain supplementaryd-methionine or when they were given water containing antibiotics. These results suggest that thed-serine andd-proline do not derive from thed-methionine supplemented in the diet or from intestinal bacteria. In urine of the ddY/DAO− mice, a substance which seemed to bed-methionine sulfoxide and/ord-methionine sulfone was present. It is probably a metabolite of thed-methionine supplemented in the diet. Thed-aminoaciduria in the mutant mice lackingd-amino-acid oxidase activity indicates that this enzyme is involved in the metabolism of thed-amino acids in normal mice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00806921
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    The amino acid composition of mammalian and bacterial cells (1997)
    Springer
    Amino acids 13 (1997), S. 379-391 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; HPLC ; Mammalian cells ; Bacterial cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary High performance liquid chromatography was used to analyze the amino acid composition of cells. A total of 17 amino acids was analyzed. This method was used to compare the amino acid compositions of the following combinations: primary culture and established cells, normal and transformed cells, mammalian and bacterial cells, andEscherichia coli andStaphylococcus aureus. The amino acid compositions of mammalian cells were similar, but the amino acid compositions ofEscherichia coli andStaphylococcus aureus differed not only from mammalian cells, but also from each other. It was concluded that amino acid composition is almost independent of cell establishment and cell transformation, and that the amino acid compositions of mammalian and bacterial cells differ. Thus, it is likely that changes in amino acid composition due to cell transformation or species differences between mammalian cells are negligible compared with the differences between mammalian and bacterial cells, which are more distantly related.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01372601
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    Paper (German National Licenses)
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