Spektrofotometrische Untersuchung des Fucoxanthin-Chlorophyll-Proteinkomplexes in Diatomeen (original) (raw)
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Traceruntersuchungen mit 71Germanium im silikat stoffwechsel von diatomeen
Zeitschrift für Pflanzenphysiologie, 1973
Silicate Metabolism in Diatoms: Tracer-Studies with 71Germanium 1. The molybdate reaction in the presence of fluoride-ions as the classical method for the determination of silicic acid does not discriminate between germanate and silicate. Therefore the radioisotope 71germanium is used as a tracer permitting studies of the germanate metabolism without analytical interference by silicate already incorporated in the cells. 2. Cells of Cyclotella cryptica take up germanate in the light and in the dark at the same rate. On the contrary, the uptake of silicate in the light is more than 3 times higher than the uptake in the dark. Therefore, the uptake reaction for silicate in the light has a much higher specificity as compared to the uptake reaction in the dark. Cells without stored carbohydrates are unable to take up germanate in the dark. But in the same cells the uptake reaction in the light is about 3 times higher as compared to cells with a normal level of carbohydrates. 3. Cells of Coscinodiscus asteromphalus (developmental stage 110 fim valve-diameter) completely inhibited in growth by germanate contain 1.5-2.2 X 10-4 fig Ge0 2 /cel1. The germanate of the cells can be extracted completely with water at 100 0 C within 5 min. During this time, only a small amount of the cell silicate has become soluble. The incorporated germanate becomes insoluble to hot water extraction by ashing the cells at 800 0 C. After separating the shells from soluble ashes more than 90 % of the 71germanium-activity is found in the shells. The results indicate that germanate is predominantly bound to the silica shells, but only at the surface and incompletely. 4. Cells of Cyclotella cryptica excrete 25 % of the previously incorporated germanate in a germanate free nutrient solution within a 6 h period in the light. In vitro, the hydrolysis of germanate by in unfractionated cell extract shows a special increases between pH 7.5 and 8.5. In the same extracts, the hydrolysis of germanate (at pH 7.6) is reduced by the action of a proteinase, pronase, to 1/3. The in vivo excretion and the in vitro experiments are understoot as first indications of a «silicatase» in diatoms. Zusammenfassung Mit dem Radioisiotop 71Germanium wurden Tracerexperimente im Silikatstoffwechsel der beiden zentrischen Diatomeen Cyclotella cryptica und Coscinodiscus asterophalus durchgefiihrt. Die Experimente ergaben eine besondere Spezifitat der Si(OH)4-Aufnahme gegeniiber der Ge(OH)4-Aufnahme im Licht, den Nachweis der nur oberflachlichen Polykondensation von Z. Pjlanzenphysiol. Bd. 70. S. 54-65. 1973. 11Germanium im Silikatstoffwechsel von Diatomeen 55 Ge(OH)4 an den Schalen von C. asteromphalus und erste Hinweise fur die Existenz elner «Silikatase» in Diatomeen.
Modulated excitation infrared (MEIR) spectroscopy is used to elucidate the photochemical reactions of pyrocatechol and diacetyl For Systems with modulated excitation, S0<->S1->T1 , chains of irreversible first and/or second order reactions and complicated radical-radical couplings, the particle concentrations are calculated as approximate analytical functions of all kinetic Parameters. The construction of a MEIR-spectrometer is described, which measures A(optical density) = 10 with a S/N = 5 and t" = 10 s in the ränge of 4000 - 1500 cm with Av. = 2.5 - 8 cm S, of pyrocatechol in CC1 is shown to yield - 2-hydroxyphenoxyradicals (I)(t= 7 ms, v(0H) = 3318 cm ) which transform via 4-chlorquinol (T = 23 min.) into 4-chlorpyrocatechol and two further photoproducts. By ab initio calculation the inplane normal frequencies of 2-hydroxyethenyl-l-oxyl (II) are obtained. Using (II) as a model substance, the low v(0H), of (I) could be traced back to the strong interaction of the ox...
Dünnschichtchromatographie von Aminosäuren und Aminen im Stuhl
Clinical Chemistry and Laboratory Medicine, 1967
Es wird eine dünnschichtchromatographische Methode zur Bestimmung der Aminosäuren und Amine im Stuhl in Form ihrer DNP-Derivate beschrieben. Die Methode gestattet eine einfache Abtrennung der Störsubstanzen und eine getrennte Bestimmung von Aminosäuren und Aminen. Bei den untersuchten Normalfällen war das Spektrum an Aminosäuren und Aminen relativ einheitlich. Die Hauptmenge der Stuhlaminosäuren besteht aus ätherlöslichen; im säurelöslichen Extrakt fanden wir bei den von uns untersuchten Stühlen praktisch nur Arginin, Taurin, Cysteinsäure und ausnahmsweise Histidin. Die Hauptmenge der Stuhlamine besteht aus Putrescin und Cadaverin. A thin layer Chromatographie method is described for the determination of feacal amino acids and amines as their DNP-derivatives. There is a simple separation from interfering substances, followed by the separate measurement of amino acids and amines. In normal cases, the pattern of amino acids and amines was relatively uniform. The majority of the faecal amino acids are ether-soluble; in the acid-soluble extract of the faeces studied, we found practically only arginine, taurine, cysteic acid, while histidine was an exception. Putrescine and cadaverine are the chief faecal amines.