Free amino Acid pools and enzymes in teratonia and habituated tobaceo tissue cultures

The free amino acid content of habituated (normal) and teratoma (abnormal) tobacco tissue cultured on white's medium were compared. Significant qualitative differences (twofold or more) were observed for serine, proline, alanine, leucine, phenylalanine, and lysine. There were qualitative differences in several unidentified ninhydrin sensitive compounds. One unknown which co-chromatographed with homo-serine was present in high concentrations (9.96 μmol/g dry weight) in habituated but was lacking in teratoma tissue, Isoenzymes of an esterase, acid phosphatase, and oxidase were demonstrated in both tissues. The distinct differences in the isoenzyme pattern of acid phosphatase suggests a differential regulatory capacity of certain phosphomonoester intermediates and P(1) . The invertase activity was higher in habituated tissue, implying a greater capacity to utilize the sole carbon source, socrose.     

IAN-bildung aus glucobrassicin: pH-Abhängigkeit und wachstumsphysiologische Bedeutung

Summary Indole auxin synthesis during enzymatic hydrolysis of glucobrassicin by myrosinase proved to be strictly dependent on pH. Neither IAN nor other indole compounds with auxin activity are synthesized at pH values higher than 5.2. An in vivo function of the indole glucosinolates as auxin precursors in Cruciferae is therefore of low probability.     

Multiple Innervation der Chromatophorenmuskelzellen von Loligo vulgaris

Zusammenfassung Die Chromatophorenmuskelzellen von Loligo vulgaris bestehen aus einer äußeren, von Sarcoplasma umgebenen Schicht scheinbar spiralig gewundener Myofibrillen und einem zentralen, hyalin erscheinenden Innenraum. Jede Muskelzelle wird von Bindegewebe umhüllt. Im distalen Abschnitt der Muskelzelle ist die kontraktile Randzone mit flügelartigen Fortsätzen versehen. An der Zellbasis öffnet sie sich zu einem schmalen Spalt, dadurch wird eine direkte Verbindung zwischen dem Sarcoplasma und dem zentralen Strang des Muskels hergegestellt. — Mittels Silberimprägnation wird eine multiple Innervation von Chromatophoren nachgewiesen. Die Pasern treten in synaptischen Kontakt mit dem Sarcoplasma und folgen der Muskelzelle in zentripetaler, gelegentlich auch in zentrifugaler Richtung. An der Zellbasis dringen Nervenfasern durch den Spalt der Randzone in das Innere des Muskels und weiter bis in die Nähe der Pigmentzelle vor. Innerhalb des Zentralstranges läßt sich eine weitere Nervenfaser darstellen und bis zur Kernregion verfolgen. Fragen einer möglichen Variabilität des Innervationsmodus der verschiedenen Chromatophoren sowie funktioneile Gesichtspunkte werden kurz diskutiert.

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Multiple innervation of the chromatophore muscle cells of Loligo vulgaris

Summary The chromatophore muscle cells of Loligo vulgaris consist of a marginal zone of apparently helically arranged myofibrils, surrounded by sarcoplasm and a central hyalinous core. Each muscle element is covered by a connective tissue sheath. In the distal part of the muscle cell the marginal zone shows a wing-shaped protrusion; at the cell basis a narrow gap is visible, establishing a close connection between the sarcoplasm and the central core of the muscle, cell. — By means of silver impregnation a multiple innervation of the chromatophores has been shown. The fibers form a synaptic contact with the sarcoplasm and follow the muscle cell in a centripetal, occasionally even in a centrifugal direction. At the cell basis nervous structures penetrate through the gap of the marginal zone and may be followed to the vicinity of the pigment cell. Within the core of the muscle another nerve fiber can be distinguished and followed up to the region of the nucleus. Questions concerning a possible variability in the mode of innervation of different chromatophores and functional aspects are briefly discussed.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.

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Zur weiteren Aufklärung der hier angedeuteten morphologischen und physiologischen Probleme sind Untersuchungen im Gange.     

Comparative studies on the regulation of DAHP synthetase activity in blue-green and green algae

Summary Regulation of DAHP synthetase activity was investigated in autotrophically grown blue-green and green algae. Members of the class of blue-green algae possess an enzyme, the activity of which is regulated by l-tyrosine and l-phenylalanine, whereby l-tyrosine is effective in 100 fold lower concentrations. DAHP synthetases of two organisms, Anabaena and Anacystis, were shown to belong to the V-type of allosteric enzymes.In contrast to the DAHP synthetase of blue-green algae regulation of this enzyme could not be demonstrated in two green algae, Ankistrodesmus and Maesotaenium. However, Euglena gracilis, both under conditions of mixotrophic and autotrophic growth, exhibits very effective regulation of this key enzyme; again, the inhibitors are tyrosine and phenylalanine. DAHP synthetase activity of Euglena has been purified about 40 fold; during this enrichment no separation of the enzyme activity inhibited by tyrosine and that by phenylalanine could be observed.