Die DNS-Synthese in Leber und Niere junger Ratten. Autoradiographische Untersuchungen mit3H-Thymidin

Summary Autoradiographic studies following a single i.p. injection of³H-thymidine were performed in liver and kidney parenchyma of new-born and young adult rats at different ages (1, 2, 4, 7, 12, 18, 24, 30, 60 and 120 days). In 1-day-old animals the tritium index (i.e. percentage of DNA synthesizing nuclei) of both organs is lower than in the rat embryo. From 1–4 days fluctuations occur, then the tritium index rises at 7 and 12 days. But now an exponential decrease is observed up to day 120. This depression and fluctuation of the tritium index probably depends on a postpartal functional transposition and especially in the liver on a structural transformation. The mean grain density in the labelled nuclei increases from 1 up to 24 days, which is likely connected with a very high amount of endogenous thymidine in new-born rats. From day 24 the mean grain density can be taken as a relative measure for the rate of DNA synthesis. The reduction in the rate of DNA synthesis from 24–120 days is explained as a consequence of the commutation from the rapid to the slow mode in cellular proliferation.

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Mit Unterstützung der Deutschen Forschungsgemeinschaft.     

Zur DNS-Synthese in Spermatogonien hypophysektomierter Ratten

Summary Atrophy of the testes was induced by hyposectomy of rats. While the differentiation of spermatids and of spermatozoons was inhibited, DNA-synthesis and mitoses of the spermatogones continued.     

Die Genomsonderung in den Mitosen der Rattenleber

Summary Model squashes with gelatine cubes containing 8 files like the chromosomes ofBellevalia romana (2n=8) showed the chromosomes only in groupings that correspond to the original position of metaphase chromosomes. The metaphase chromosomes in root tip cells ofBellevalia romana are arranged at random; there is neither somatic pairing nor genome segregation (= grouping of metaphase chromosomes into two complete chromosome sets). In contradiction to these results, the chromosomes in the regenerating liver cells (2n=42) show a certain precentage of grouping into complete genomes. It is concluded that in rat liver cells a mechanism exists which, starting with the genome segregation, may produce a change in chromosome number. Thus these same euploid or aneuploid chromosome numbers can be explained which are really observed in normal and treated rat liver. 4 possibilities of such mechanism are discussed.

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Nach einem Vortrag, gehalten anlässlich des IV. Symposium histologicum internationale Lausanne (Suisse), 5.–8. September 1961.     

Rezente und fossile Lebensspuren,ihre Deutung und geologische Auswertung

Summary A study of the recent tracks and trails is important for the interpretation of the fossil ones with which palichnology, as a branch of paleontology, has to deal in contrast with the more significant fossils preserved as shells, bones etc. Only such a study can prevent the errors being possible on the geological, especially paleogeographical interpretation of fossil tracks. The ecological point of view is a determining factor for their classification and determination while a classification according to taxionomic units is not possible.     

Über Ursprung und Funktion einiger Methylgruppen in verzweigten Fettsäuren,in Pflanzensterinen und in Chinonen der Vitamin-K- und Ubichinongruppe

Summary In the first part of this review the biogenesis of methyl-branched bacterial lipids through incorporation of the methyl group of methionin or of propionic acid is studied; it is shown that in the biogenesis of tuberculostearic acid, only two hydrogen atoms are transferred with the carbon of methionin. The same observation is made in the second part, concerning the origin of the 24-methyl group of ergosterol. Different mechanisms of C-methylation by methionin are discussed. It is also shown that the ethylidene group of fucosterol is formed by a double transfer of the methyl carbon of methionin.In the third part the possible biological function of the 2-methyl group of vitamin K and the ubiquinones is studied; the acid catalysed isomerisation of these compounds to very reactive methylene-quinone-chromanes is discussed in detail.

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SechstePaul-Karrer-Vorlesung, gehalten am I. Juli 1964 an der Universität Zürich; ein ähnlicher, englischer Text wird als «Second Jubilee Lecture» der Biochemical Society im Biochemical Journal, im Druck (1964), erscheinen. — Unsere Arbeiten wurden durch Grant AI-02838 vom National Institute of Health (U.S. Public Health Service) und durch Unterstützungen des Commissariat à l'Energie Atomique, Saclay, gefördert.     

Struktur und Wirkung des Muscarins,des Muscarons und ihrer Stereoisomeren

Summary All synthetic isomers of (+)-muscarine, the racemic forms of epi-muscarine, allo-muscarine, and epiallo-muscarine are at least 100 times less potent on blood pressure of cats and isolated frog hearts than the natural alkaloid. Only muscarones are more potent and exhibit strong nicotinic action on the frog rectus and in blocking ganglionic and neuro-muscular transmission in the cat. They closely resemble acetylcholine in their structure and action.The activity of the isomers depends on the position of the constituents on the tetrahydrofurane ring. Steric hindrance of the hydroxy or carbonylgroup and of etheroxygen plays an important part in the contact with the cholinergic receptor. As nor-muscarine without the quarternary nitrogen is inactive, at least 3 different points of contact have to be considered. This is stressed by the fact that muscarine is highly stereospecific in its action, whereas muscarone is not.     

Elektronendichte und Polarität bei Benzol,Naphthalin und Anthracen

Summary For the aromatic molecules benzene, naphthalene, and anthracene a relation is found between dipole moment and dissociation constant of the hydroxy compounds and the carboxylic acids on the one hand and the-electron density at the respective carbon atom in the unsubstituted molecule on the other hand. The following statement can be made:—The-electron density at a carbon atom of these aromatic systems is found to increase with its positive character. The effect is explained by using an electrostatic model.     

Synthese und biologische Aktivität bradykininwirksamer Undeca-, Dodeca- und Tridecapeptide

Summary Several undeca-, dodeca- and tridecapeptides, analogues of the naturally occurring methionyllysyl-bradykinin, have been synthesized. The biological activities of the new compounds on the isolated rat uterus, guinea-pig ileum and rabbit blood pressure are presented.

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über Peptidsynthesen XXXIV. 7. Mitt. über Bradykinin- und Kallidin-Analoga. XXV. Mitt. über Peptidsynthesen, 6. Mitt. über Bradykinin- und Kallidin-Analoga:E. Schr?der, H.-S. Petras undE. Klieger, Liebigs Ann.679, 221 (1964).     

Die Verteilung der Na- und Cl-Ionen zwischen Blutserum einerseits,Pleurapunktat, Ascites und Liquor cerebrospinalis andererseits

Summary We determined the sodium, chloride, and protein content of sera on the one hand, and the same constituents in pleural, ascitic and cerebrospinal fluid on the other. We found the proportions of sodium and chlorine of serum and corresponding fluid to be identical with the proportions calculated according tovan Slyke's formula on the basis of the Donnan equilibrium. Consequently one cannot draw any diagnostic conclusions from the sodium or chlorine content of these fluids, as they depend solely on the sodium or chlorine content of the serum and the protein content of the serum and fluid.     

Peroxidase-Isoenzyme in Kressekeimlingen (Lepidium sativum L.) und ihre Hemmung durch Silybin,Silydianin und Silychristin

Summary Seedlings ofLepidium sativum L. contain 4 peroxidase isoenzymes. Their de-novo-synthesis is significantly depressed in the presence of 3·10^–3 moles/l silybin, silydianin and silychristin in the incubation medium respectively.     

Quantitative und qualitative Untersuchungen der Esteraseaktivität in normalen Granulozyten,normalen Lymphozyten und in leukämischen Zellen

Summary A quantitative and qualitative analysis of the carboxylic esterases of normal granulocytes, normal lymphocytes and leukemic cells was performed. In the myeloid leukemic cells and in the lymphatic leukemic cells, the esterase activity was significantly increased. By means of electrophoretic fractionation, four zones with esterase activity were detected in normal granulocytes and lymphocytes; the electrophoretic pattern of the leukemic cells was similar to that of the normal cells.

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Diese Forschung wurde vom Fonds des Lady Tata Memorial Trust unterstützt.     

Zikadenendosymbiose: Eucyten-Struktur-, -Funktions- und -Evolutions-Modell

Summary The mitochondria can be considered as extremely integrated endosymbionts, according to the theory of the endosymbiontic origin of eucytes. Leafhoppers show also very integrated endosymbionts. Their protoplastoid-, rickettsia-and bacteria-like endosymbionts differ, according to grade, kind and supposed age of the relation, from the hypothetical type of mitochondria. Mitochondria and protoplastoids differ the least and show corresponding physiological behavior. Both have a regulative influence on pH and osmotic pressure of the eucyte and use probably the same mechanism of regulation. The protoplastoid endosymbiosis of leafhoppers can be regarded as a missing link between the temporary endosymbiosis of the bacteria and the permanent hypothetical one of the mitochondria. The leafhopper endosymbiosis is a suitable model for the analysis of structure, function and evolution of the eucyte.     

Ein chemisch und pharmakologisch neuartiger Antagonist von pathophysiologisch bedeutsamen Aminen,Kininen und kininbildenden Faktoren

Summary CIBA 21 401-Ba, a glucofuranoside derivative (ethyl-3,5,6-O-benzyl-d-glucofuranoside), antagonizes in vitro the smooth-muscle action of a large number of biogenic amines and polypeptides, the accelerated migration of leucocytes induced by endotoxin, and the Schultz-Dale phenomenon. In vivo, the compound shows anti-inflammatory and anti-allergic effects and improves the survival rate of infected mice treated with suboptimal doses of a sulphonamide.     

Die bakteriostatische Wirkung von Chalkon,Flavanon, Flavon und Flavonol

Summary Chalcone, flavanone, flavone, and its derivatives had a certain bacteriostatic effect onSt. aureus. Flavonol has no activity and morin, a derivative of flavonol, showed only a weak inhibition of the bacterial growth.Cystein did not have any antagonistic effect.Extracts of drugs, which contain natural flavanones, flavones, isoflavones and flavonols, are more or less bacteriostatic.     

Spurenelemente einiger schweizerischer Ophiolithe,Radiolarite und Mergel

Summary The trace element content of a few Swiss ophiolites, radiolarian cherts and marls has been determined by means of spectrographic methods.Field observations, microscopical and spectrographical data lead to the conclusion that the colour of green cherts in certain areas is due to the supply of clastic peridotite- and serpentine-particles originating from a syn-temporaneous ultrabasic igneous body.     

Die Verteilung von Noradrenalin und Adrenalin im Herzen der Katze,des Kaninchens und der Ratte

Summary The concentration of noradrenaline in different parts of the heart was estimated in cats, rabbits, and rats. In each heart, the concentration of noradrenaline was much higher in the right atrium than in the left atrium and higher in the right ventricle than in the left one.     

Über den Einfluss von Natriumsulfit,Natriumtellurit und Natriumselenit auf die Retention von Zink,Kadmium und Quecksilber im Organismus

Summary The influence of sodium sulfite, sodium tellurite and sodium selenite on the retention of zinc, cadmium and mercury in mice was studied. The retention of mercury was increased by sodium selenite and by sodium tellurite. The retention of cadmium was increased only by sodium selenite. Sodium sulfite did not influence the retention of metals studied. The retention of zinc was not influenced by any compounds used.     

Zu Einsteins letzter Vorlesung — Beobachtbarkeit,Realität und Vollständigkeit in Quanten- und Relativitätstheorie

Ohne Zusammenfassung Vorgelegt von J. D. North     

Artbastarde in der GattungTilapia (Cichlidae,Teleostei) und ihr Verhalten

Summary The young ofTilapia mossambica (mouth-brooder) show a characteristic contact-behaviour, which is related to the behaviour of the mother fish, who takes them back into the mouth cavity in cases of disturbance. This contacting is lacking in the young ofTilapia tholloni (substrate spawner). Contacting, as studied in our experiments with models, is genetically determined and is dominant over thetholloni pattern in the crossT. mossambica ×T. tholloni .     

Entwicklung und Probleme der Schnee- und Gletscherkunde in der Schweiz

Ohne ZusammenfassungAbteilung für Erdbauforschung der Versuchsanstalt für Wasserbau an der ETH.