Protein- und RNS-Gehalt des Hypokotyls beim stationären Wachstum im Dunkeln und unter dem Einfluß von Phytochrom (Keimlinge von Sinapis alba L.)

Zusammenfassung Das Wachstum des Hypokotyls wurde an Restkeimlingen ohne Kotyledonen (Abb. 1) untersucht. Die Wachstumsgeschwindigkeit ist in dem von uns untersuchten Zeitraum sowohl im Dunkeln als auch unter dem Einfluß von P₇₃₀ (Dauer-Dunkelrot) praktisch konstant. Obgleich sich die Wachstumsgeschwindigkeiten im Dunkeln und im Dauer-Dunkelrot um den Faktor 4 unterscheiden, hat das Dunkelrot keinen signifikanten Einfluß auf den Gesamt-Proteingehalt des Hypokotyls (bzw. der durchschnittlichen Hypokotylzelle). Der Proteingehalt nimmt im Dunkeln und im Licht kontinuierlich ab. Auch der Gesamt-RNS-Gehalt zeigt innerhalb des Versuchszeitraums eine Abnahme, die unter dem Einfluß von Dunkelrot früher einsetzt als im Dunkeln. — Man kann aus den Daten der vorliegenden Arbeit schließen, daß nur ein kleiner Teil des Gesamt-Proteins und der Gesamt-RNS einer Zelle mit dem Zellwachstum unmittelbar in Verbindung gebracht werden kann.

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Protein and RNA contents of the hypocotyl during steady state growth lengthening in the dark and under the influence of phytochrome (seedlings of sinapis alba L.)

Summary Inhibition of hypocotyl lengthening by phytochrome can be regarded as a prototype of a negative photoresponse. The hypothesis has been advanced (Schopfer, 1967) that negative photoresponses are the consequence of a differential gene repression which is exerted by P₇₃₀, the active phytochrome. This hypothesis is mainly based on experiments with specific inhibitors of RNA- and protein synthesis. —The present paper is part of an experimental program which has been designed to check this hypothesis.—Continuous irradiation with standard far-red has been used to establish a virtually stationary concentration of P₇₃₀ over the whole period of experimentation (36–60 hours after sowing). To correlate more strictly the growth response of the hypocotyl with molecular changes in this organ the axis system without cotyledons has been used (Fig. 1). Even under these conditions the growth rate of the hypocotyl is nearly constant in light (continuous far-red) and dark during the whole period of experimentation (36–60 hours after sowing) (Fig. 2, 3). It is known from earlier experiments that cell division in the hypocotyl are very rare during this period and that there is virtually no increase in the DNA contents of the organ during the period of our experimentation (Weidner, 1967). Obviously the number of cells per hypocotyl is virtually constant between 36 and 60 hours after sowing. Organ (i.e. hypocotyl) lengthening is nearly exclusively due to cellular lengthening.—If we follow the protein contents of the hypocotyl we find (Fig. 4) that the total protein of the organ decreases steadily in spite of the fact that the organ grows at a constant rate. There is no significant difference in protein contents between dark-grown and far-red grown systems although the growth rates differ by a factor of 4 (Fig. 2, 3).—The situation is some-what different with respect to total RNA (Fig. 5). The RNA contents eventually decrease in far-red as well as in dark-grown systems but the decrease is significantly faster in the far-red treated systems than in the dark controls.—It is concluded that only a very small part of the total RNA and total protein of a cell can be related to the control of cellular growth. Changes in bulk RNA and bulk protein obviously do not necessarily reflect changes in the growth rate or growth capacity of an organ or a cell.

     

Studies on nucleic acids. VIII. Changes in the stability of DNA secondary structure by interaction with divalent metal ions

The melting temperature of a natural DNA is decreased in the presence of increasing amounts of copper ions, whereas other divalent metal ions stabilize the DNA secondary structure at low ionic strength. At 1.28 × 10^?4M, Cu²⁺ produces a decrease of T_m depending on base composition. At very low Cu²⁺ concentrations (0.5 Cu²⁺/2 DNA-P) a stabilization of the DNA conformation appears due to an interaction between Cu²⁺ and phosphate groups of the DNA molecule. In this case the normal trend of GC dependence of T_m exists similar to that with Na⁺ and Mg²⁺ as counterions. If copper ions are in excess, the observed destabilization is stronger for DNAs rich in guanine plus cytosine than for those rich in adenine plus thymine. A sharp decrease of T_m occurs between 0.5–0.8 Cu²⁺/2 DNA-P and 1.5 Cu²⁺/2 DNA-P. The breadth of the transition decreases at high Cu²⁺ concentration with further addition of copper ions. Denaturation and renaturation experiments indicate that Cu²⁺ ions exceeding the phosphate equivalents interact with the bases and reduce the forces of the DNA helix conformation. Evidence is presented, that the destabilization effect produced by Cu²⁺ is possibly due to an interaction with guanine sites of the DNA molecule.     

Dominant erbliche doppelseitige Dysplasie und Synostose des Ellenbogengelenks

Symmetrical dysplasia of the elbow joint and humero-radial synostosis together with brachymesophalangism, shortening of metacarpale I, and synostosis of carpal and tarsal bones in a boy, his mother and most probably also his grandmother is described. The combined malformations resemble closely those reported in a father and his daughter by Joachimsthal and in a father and his son by Mouchet and Saint-Pierre. It is suggested that this may represent a distinct hereditary entity.

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Kommissarischer Direktor: Prof. Dr. G. Jentschura     

Autoradiographies de Coupes d'os compact après marquage aux isotopes in vitro

Résumé Etude qualitative et quantitative du marquage in vitro de coupes d'os compact. Détermination du rôle joué par les processus de diffusion, d'adsorption et d'échange dans ces phénomènes.

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Zusammenfassung Qualitative und quantitative Studie der in vitro-Markierung von Schliffen aus Knochen-Compacta. Bestimmung der Rolle der Diffusions-, Adsorptions- und Austauschprozesse für diese Vorgänge.

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Avec 2 Figures dans le Texte

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La partie expérimentale de ce travail a pu être réalisée grâce à des subsides fournis par l'European Office of the Air Research and Development Command [contrat n^o AF 61 (514) 1175], par l'Institut Interuniversitaire Belge des Sciences Nucléaires, et par la Commission pour la Science Atomique du Fonds National Suisse de la Recherche Scientifique.     

Zum histochemischen Phosphorylasenachweis im Herzinfarkt

Summary The demonstration of glycogen by PAS-method and the reaction of phosphorylase by Takeuchi et al. were performed in the hearts of rats 30 min after experimental coronary occlusion. While the cardiac muscle cells in the center of the ischemic region still contained glycogen, the cells in the border zone of the infarction did not. The phosphorylase activity was demonstrable only in those cardiac muscle cells which contained glycogen. As well known that the demonstration of phosphorylase activity is possible only if glycogen as starter is present, it is concluded that the lack of phosphorylase activity by the histochemical reaction in cells which do not contain glycogen doesn't prove the absence of the enzyme.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.

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Stipendiat der Alexander von Humboldt-Stiftung.     

Beziehungen zwischen den Endothelzellen der Lebersinusoide und den von Kupfferschen Sternzellen Elektronenmikroskopische Untersuchung

Summary Zymosan given to rats, normal or splenectomized, stimulates the RES of the liver. Under this stimulation, the endothelial cells of the sinusoids change into Kupffer cells. The endothelial cells become hypertrophic and multiply; they acquire progressively the properties of phagocytosis and of digestion shown by the Kupffer cells. Hence both types of cells — the endothelial and the Kupffer cells — belong to the same cellular lineage. Their various aspects result from different functional states.The hyperplasia of the liver RES has no repercussion on the fine structure of the hepatic cells.

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Résumé L'administration de Zymosan à des rats, splénectomisés ou non, provoque une stimulation du SRE du foie. Sous l'effet de cette stimulation, les cellules endothéliales des sinusoïdes se transforment en cellules de Kupffer. Les cellules endothéliales s'hypertrophient et se multiplient; progressivement, elles acquiérent les propriétés de phagocytose et de digestion des cellules de Kupffer. Les deux types de cellules — endothéliales et cellules de Kupffer — appartiennent donc bien à la même lignée cellulaire. Leurs divers aspects correspondent à des états fonctionnels différents.L'hyperplasie du SRE du foie n'a pas de répercussion sur l'ultrastructure des hépatocytes.

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Mit Unterstützung durch den Schweizerischen Nationalfond für die Förderung der Wissenschaftlichen Forschung.

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Stipendiat der Organisation Mondiale de la Santé.Übersetzung von Frau Antje Forssmann, technische Mitarbeit von Max Baumann, Michel Bernard und Charles Moreillon.     

Zur Verbreitung der ABO-Blutgruppen in der Bevölkerung Nordthailands

2048 subjects in North Thailand were examined for AB0 blood groups. A control group representative of the population of the provinces of Chiengmai and Lampun was formed of 382 examinees and 3403 blood donors.The distribution of AB0 groups in this population is similar to that of Central Thailand. Some ethnic groups show significant deviations: The Miao tribe, originating in South China, has a much higher frequency of B. There was a significant reduction in gene A and B in the younger generation of this tribe. The Thai Yong, people who migrated to North Thailand from Yunnan in the 19th century, show an AB0 distribution similar to Chinese in Yunnan. They differ significantly from the Northern Thai. There is also a difference in the distribution of -thalassaemia and hemoglobin E between these two groups.Male leprosy patients showed an excess of group A which was not present in female patients. The percentage of severely ill patients was much higher in the males. Differentiation into lepromatous and tuberculid forms is not available. Among 108 people who had suffered from smallpox approximately 20 years ago there was an excess of groups 0 an B in comparison to the control group.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Burrowing,grooming, and feeding behaviour of Paraceradocus,an antarctic amphipod genus (Crustacea)

Summary Species of the amphipod genus Paraceradocus found near the Antarctic Peninsula were observed in aquaria. The animals live under stones in burrows in sediment which they excavate with their gnathopods. During burrowing the animal regularly turns backwards in a somersault-like movement. Paraceradocus feeds on detritus, which is manipulated by the gnathopods and the antennes. The gnathopods are also used for grooming. A dense brush of setae at the medial surface of the carpi of the gnathopods I is used to clean off fine particles from the antennes. These particles are transferred to the maxillipeds and are ingested. The rear appendages are mainly cleaned by the gnathopods II. Young animals sitting between the gnathopods of the adult participate in feeding.     

Simulated and measured nitrogen conditions in a manured and fertilised soil

The governing factors for soil nitrogen dynamics were identified with a simulation model. In addition, the model was used to interpret measurements from a plot fertilisation experiment in southwest Sweden.Simulated moisture and temperature conditions were the driving variables for the simulation of soil nitrogen dynamics and leaching during a 6-year period. The results of the simulation were compared with monthly observations on two plots with grain crops, one with liquid manure and commercial fertilisers applied and one with commercial fertilisers only.Simulated temporal variations of the nitrate and ammonium storages generally agreed with observations. The dominant role of the crops as a determinant of soil nitrogen conditions was demonstrated. A higher leaching loss from the plot with application of commerical fertilisers only occurred both in simulations and measurements compared to the plot with application of both commercial fertilisers and manure. The main reason was the higher N-application in the former treatment.The effect of water flows in macropores was interpreted as a delay of simulated leaching compared to observed leaching on some occasions in summer and early autumn. No direct effect of the macropores on the yearly rates of leaching could be seen.