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  • 1965-1969  (2)
  • 1940-1944  (2)
Materialart
Erscheinungszeitraum
Jahr
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Antonie van Leeuwenhoek 31 (1965), S. 137-144 
    ISSN: 1572-9699
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract N-SERVE, 2-chloro, 6-(trichloromethyl)pyridine, shown to be a potent inhibitor of the ammonia oxidase system ofNitrosomonas was not effective at all in theNitrobacter nitrite oxidizing system at concentrations which had caused complete inhibition of ammonia oxidation, i.e. 1 – 1.5 ppm of the chemical. Very little inhibition of nitrite oxidation by intact cells was observed even in the presence of 50 ppm N-SERVE. Concentrations of 80 to 175 ppm, however, inhibited the nitrite oxidation by 60 to 75 percent. The cell-free nitrite oxidizing system of the chemoautotroph was found to be virtually unaffected by these unusually high concentrations of the inhibitor and 175 ppm concentration caused only a 10 percent inhibition. As in theNitrosomonas systems, N-SERVE proved to be inhibitory for the cytochrome oxidase present in the cell-free extracts ofNitrobacter but, again, levels from 80 – 175 ppm of the inhibitor were required for a 50 percent inhibition of the enzyme. The nitrite activating enzyme “nitrite-cytochromec reductase” was scarcely affected by these levels of N-SERVE. As a matter of fact, a slight stimulation of enzyme activity was observed. Copper ions, as in the case ofNitrosomonas, effectively reversed the N-SERVE inhibition of theNitrobacter cytochrome oxidase system.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    [s.l.] : Nature Publishing Group
    Nature 153 (1944), S. 745-745 
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] THE presence of p-cresol in human urine, as well as in the urine of horses, cows and other animals, has been known for a long time. It occurs mainly as a salt of p-tolylsulphuric acid. According to Siegfried and Zimmermann1, the average concentration of p-cresol in normal human ...
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Antonie van Leeuwenhoek 31 (1965), S. 124-136 
    ISSN: 1572-9699
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Studies were conducted to elucidate the mechanism of action of 2-chloro-6-(trichloromethyl)pyridine or Technical N-SERVE on the nitrification process brought about byNitrosomonas europaea. The growth ofNitrosomonas was completely inhibited in the presence of 0.2 ppm N-SERVE while 1.0 ppm of the chemical was effective in the complete inhibition of ammonia oxidation by fresh cell suspensions. Cells stored at 4 C for a period of three days required somewhat higher concentrations (1.5 ppm) of N-SERVE for the complete inhibition of their ammonia oxidizing ability while the cytochrome oxidase of these cells was inhibited to the extent of 65 to 70 percent in the presence of a corresponding amount of N-SERVE. A 45 – 70 percent reversal of the inhibition of ammonia oxidation caused by N-SERVE was obtained by the addition of 6×10−4 M Cu++. An equivalent concentration of Cu++ was also effective for the complete reversal of the inhibition of cytochrome oxidase present in whole cells. Hydroxylamine oxidation by intactNitrosomonas cells was not affected by levels of N-SERVE ranging from 1 – 3 ppm. The cytochrome oxidase effective in hydroxylamine oxidation and present in cell-free extracts was not inhibited by even 100 ppm N-SERVE. Likewise, the hydroxylamine activating enzyme “hydroxylamine cytochromec reductase” was also not inhibited by such levels of the chemical. Raising the concentration to 170 ppm N-SERVE, however, caused a 90 percent inhibition of the enzyme. Although a 5×10−6 M concentration of allylthiourea completely inhibited ammonia oxidation byNitrosomonas cells, concentrations up to 10−3 M of this compound did not affect the cytochrome oxidase activity of whole cells or cell-free extracts. The inhibition of ammonia oxidation caused by 5×10−6 M allythiourea, unlike the inhibition by N-SERVE, could not be reversed by the addition of 6×10−4 M Cu++. Evidence is presented that the action of N-SERVE is on that component of cytochrome oxidase which is involved in ammonia oxidation.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    ISSN: 1618-2650
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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