Untersuchungen über die Genetik der Aposporie bei pseudogamen Potentillen

Summary It may be supposed that the somatic and generative apospory of the genusPotentilla is due to different factors and that these factors have a quantitative effect.     

Untersuchungen über die Bildung der Reblaus-Blattgalle

Résumé La transmission expérimentale de la salive du Phylloxéra peut stimuler les jeunes feuilles de la vigne se trouvant encore dans la phase de végétation à former des galles. A cet égard, l'endopolyploidisation du tissu foliaire qui est exposé à la stimulation de la formation gallicole prouve un événement fondamental de la cécidogenèse.     

Untersuchungen über die Biosynthese der Vitamine der Folsäuregruppe bei grünen Pflanzen

Résumé Des plantules de Pisum sont cultivées aseptiquement en milieu synthétique. A la lumière, elles synthétisent plus de facteurs du groupe de l'acide folique, déterminés par voie microbiologique, et plus d'acide ascorbique qu'à l'obscurité. L'adjonction d'acide ascorbique au milieu des plantes cultivées à l'obscurité compense partiellement l'absence de lumière.     

Über die Reizung des Ferntastsinns bei Fischen und Amphibien

Summary Fishes and aquatic amphibians are able to detect and locate moving bodies and even obstacles at some distance by means of their lateral-line sense organs (Ferntastsinn). As was shown experimentally, the main physical process involved in these reactions are certain local damming phenomena in front of the moving object (rise of pressure, displacement of water particles). Obstacles cause an alteration of the damming phenomena produced by the moving animal's body itself (increase of water resistance).Kramer's different view is rejected; he overlooked the existence of damming phenomena and was not aware of the fact thatXenopus laevis reacts to surface waves even when the animal is totally submerged.     

Untersuchungen über die Nikotinbildung des Tabaks

Summary During germination the tobacco seedling produces nicotine from proteins accumulated in the seed. Later on the nicotine formation of the growing tobacco plant is dependent on the protein synthesis in its root. The comparison of theprotein production by the tobacco root with thenicotine content of the whole plant shows an interesting parallelism.     

Elektrophysiologische Untersuchungen über die Ultraviolettempfindlichkeit von Insektenaugen

Summary Using the electroretinogram, the relative spectral sensitivity of the compound eye of the cockroachPeriplaneta americana and the flyCalliphora erythrocephala has been measured between 347 and 673 m μ. Besides the well known sensitivity distribution for spectral lights between red and blue, a further rise of sensitivity is demonstrated in the violet and ultraviolet part of the spectrum, reaching the highest value at the shortest wavelength available. Using selective adaptation (P. am.) and different stimulus intensities (C. er.), sensitivities for ultraviolet light were shown to be independent from those in the remaining part of the spectrum. Thus, more than one photopigment are assumed to be present in these eyes, one of them responsible for vision in the ultraviolet.

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Mit Unterstützung der Deutschen Forschungsgemeinschaft.     

Untersuchungen über Aktinpolymerisation

Summary The suggestion is put forward that the polymerisation and ATP-splitting in actin are independent processes and that perhaps fats and lipoids are concerned in ATP-actin binding. (A comparison is made between the strength of ATP-binding of different actins.)     

Neuere Ergebnisse über die Raumstruktur der Tropanalkaloide

Ohne Zusammenfassung     

Weitere Untersuchungen über die Wirksamkeit von Oxytryptaminderivaten im Strahlenschutzversuch

Summary The radioprotective action of some further oxytryptamines is investigated and the structure-activity relationship discussed. Deseril which neutralizes the protective effect of oxytryptamines, does not impair the radioprotective properties of cysteamine, tyramine, histamine or noradrenaline.     

Vergleichende Untersuchungen über die hypertensive Wirkung von Aldosteron und Desoxycorticosteron

Summary In the adrenalectomized and unilaterally nephrectomized rat an investigation has been carried out on the influence of a four weeks' treatment with aldosterone and desoxycorticosterone-acetate in doses which are equieffective concerning sodium retaining capacity. Desoxycorticosterone-acetate produced hypertension, perivascular granuloma and renal lesions, whereas under the influence of aldosterone the blood pressure remained normal and no histopathological alterations could be found. Towards the end of the experiment the animals treated with desoxycorticosterone-acetate took up twice as much drinking fluid as the animals treated with aldosterone. Although the results obtained so far are only of a preliminary character it is obvious that aldosterone in doses which are equieffective concerning sodium retention does not produce the same side effects as desoxycorticosterone-acetate.     

Vergleichende Untersuchungen über die Dekorporationseffektivität einiger neuerer Chelatbildner

Summary The influence of several new polyaminopolycarboxylic acids on the distribution of carrierfree radiocerium in the organs of the rat was studied. Some theoretical and practical implications of the experimental findings are discussed.     

Elektronenoptische Untersuchungen über die Entstehun g «stachliger» Streptomyces-Sporen

Summary It is demonstrated, by electron-optical photography in a Streptomyces strain of the morphological section spira, that the spines of the spores arise from the membrane of the aerial mycelium hyphae and can be decomposed by lysozyme.     

Weitere Untersuchungen über strukturabhängige Wirkungsunterschiede bei Cardenoliden und Bufadienoliden

Summary By means of guinea-pig auricle preparations, which were damaged in some way, it was demonstrated that bufadienolids compensate different model insufficiences more efficaciously than cardenolids; and 3,14,12-trihydroxygenins more efficaciously than 3,14-dihydroxygenins, and even better than 3,14,16-trihydroxygenins.     

Über die Auslösung der Fluchtreaktion bei Fliegen

Summary Contrary toGaffron, 1934, it has been shown that when flies flee from the catching hand, this reaction is merely due to optical stimuli (experiments with flies behind glass). Air movements play no part in this connection (experiments with blinded flies).     

Tierexperimentelle Studien über die Alkoholverbrennung

Summary While in dogs intravenously administered alcohol is eliminated as a straight function of time, it was found that the combustion of alcohol, when given intraperitoneally in rats, depends on the concentration at a given time. Since the dog — like man — belongs to a species with a slow alcohol combustion, while the rat (together with the mouse) has the highest metabolic velocity, it is supposed that the supply of alcohol dehydrogenase might determine not only the metabolic velocity as such but also the rhythm of alcohol combustion: when the ADH supply is low, the combustion capacity limit will be reached at low blood alcohol concentrations and the elimination curve will become linear.     

Regel über die nichtbesetzten Isotonenzahlen

Summary Of the neutronic numbers 1 to 126 nine are not represented by a stable isotope. The non existent neutronic numbers are those between the neutronic numbers of the two isotopes of an element with an odd atomic number.