Über die Biosynthese des β-Carotins beiMucor hiemalis. Die Beteiligung der Essigsäure am Aufbau des Carotinmoleküls,untersucht mit Hilfe C14-markierter Essigsäure

Summary It has been demonstrated with labelled acetate, C¹⁴H₃ . COONa, CH₃-C¹⁴OONa), that the methyl groups of acetic acid form the methyl groups of the chain between the two-jonone rings of the-carotene. The carboxylic groups of the acetic acid on the other hand form the neighbouring C-Atoms of the methyl groups.     

Über einen Cortison-äquivalenten Katalysator der Autoxydation der Linolsäurein vitro

Summary Acetophenone derivatives with a cortisone-like side chain have been investigated for their catalytic effect on the autoxydation of linolenic acid.-Hydroxy-acetophenone and the substituted-hydroxy-3,4-dimethoxyacetophenone are the substances with the simplest structure having a catalytic effect quantitatively and qualitatively similar to that of cortisone.The significance of substituents in the ring for the catalytic activity of the side chain is discussed.     

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).     

Der Einfluss der Pantothensäure,des Pantethins und des phosphorylierten Pantethins auf die Carotinbildung beiMucor hiemalis

Summary Pantothenic acid, pantethine, and probably also phosphorylated pantethine stimulate the production of carotenoids by the fungusMucor hiemalis.     

Über die Adsorptionskraft der Pektine in organischen Lösungsmitteln

Summary Pectin does not present any surface activities in organic solvents. An eventual fixation of some substances is based on mutual chemical affinity.     

Über den Föhn

Ohne Zusammenfassung     

Über einen Gradienten in der Samenschale vonCrepis capillaris bei der Keimung und seine mutmaßliche Bedeutung

Summary In the seed-coat ofCrepis capillaris a gradient is formed shortly before the germination. It consists in the growth of all the cells in a small, sharply delimited area at the end around the root-tip. This process takes place under a decrease of the thickness of the walls and a consumation of the reserve materials of the cells. The rest of the cells in the shell, which can not be distinguished from the cells of the pole during and after the swelling, remain at the same time unchanged. It is supposed that the gradient causes the germination of the root prior to the cotyledones. The investigations are being continued.     

Über die Temperaturabhängigkeit der Galvanonarkose bei Fröschen

Summary The relation of the threshold current dose to the temperature constitutes a function of the chain-line type (hyperbolic function).From the dependence of the recovery time after galvanonarcosis upon the temperature it is concluded that by the passage of direct current molecular arrangements on surfaces are reversibly disturbed.     

Über den Mechanismus der Osazonreaktion

Summary For the osazone reaction of the reducing sugars, the following mechanism is suggested: the initially formed phenylhydrazone is converted with aniline into the N-glycoside. Aniline arises from disproportional decomposition of phenylhydrazine. The N-glycoside undergoes an Amadori-rearrangement to 1-deoxy-1-amino-2-ketose derivative. From this is formed the phenylhydrazone. The latter is converted by dehydrogenation and transamination into the phenylosazone.     

Über die Wirkungsweise der Katalasen

Ohne ZusammenfassungHauptreferat, gehalten vor der Schweizerischen Medizinisch-Biologischen Gesellschaft in Genf am 31. August 1947, anläßlich der 127. Generalversammlung der Schweizerischen Naturforschenden Gesellschaft.     

Über den Stoffwechsel der Nebennierenrindenhormone

Summary Three reactions, the 11- and the 21-hydroxylation as well as the oxydation of the angular carbon 18, are specific for the adrenals. All other enzymatic steps in the biosynthesis of steroidhormones have been demonstrated in some other tissues also. Cofactors for the hydroxylation of steroids are reduced pyridinenucleotides. They seem to be necessary to activate molecular oxygen.The extra-adrenal metabolism of adrenal hormones occurs mainly in the liver. Four principal reactions are known: the reduction of the ⁴-3-on-, the 11-keto-, and the 20-keto-group as well as the conjugation of steroids with glucuronid acid. Evidence is given that the liver is the main target of corticosteroid action.     

Über die Funktion der Lorenzinischen Ampullen der Selachier

Summary The afferent impulses from the ampullae ofLorenzini ofScyllium show, both in the intact animal and in the isolated preparation, a steady discharge at constant temperature with a frequency reaching a maximum at an average of 20° and decreasing continuously at higher and lower temperatures. The discharge stops between 5° and 30° on the average. Rapid cooling causes a temporary rise in frequency, while rapid warming causes a temporary drop in frequency. While the ampullae are not sensitive to a mechanical stimulus, they react definitely to a change in temperature of 0.05°C. The ampullae thus behave like the cold receptors of the homoiotherms.     

Über Ester der Polygalakturonsäure

Summary Polygalacturonic acids (pectic acids) can easily be esterified by epoxides (ethylene oxide, 2,3-epoxy-1-propanol, epichlorhydrin, etc.) in the presence of water. Under favorable conditions the degradation of the macromolecules is negligible. Some properties of the glycol esters of polygalacturonic acid which are similar to those of the methyl esters of polygalacturonic acid (pectinic acids) are described. The glycol and glycerol esters, however, are not saponified by the enzyme pectase. These compounds react much more rapidly with formaldehyde than pectinic acid which does not possess primary hydroxyl groups.     

Über die optimale Zusammensetzung der Nahrung

Résumé La notion d'«alimentation optimale», préconisée parMacCollum, est soumise à une critique au cours de laquelle l'auteur montre les difficultés qui se présentent lorsque l'on veut préciser cette notion. Il relève le rôle encore peu clair que joue la flore intestinale pour la synthèse de substances essentielles à l'alimentation de l'homme. La quantité optimale nécessaire n'est en matière d'alimentation pas une valeur stable, car elle dépend de la situation générale du métabolisme, ainsi que le prouvent certains exemples de la physiologie des vitamines B.Une méthode particulièrement adéquate, spécifique pour reconnaître une situation optimale de l'alimentation, est donnée dans la méthode d'autosélection («self selection»), plus spécialement sous la forme développée parC. P. Richter. On peut trouver bien des analogies entre les résultats expérimentaux et certains faits connus de l'alimentation humaine. En ce qui concerne le régime optimal pour l'homme, seules les expériences sur l'homme sont déterminantes, comme elles ont été entreprises aux Etats-Unis au cours de la dernière guerre chez des volontaires.Les recherches expérimentales sur l'effet que les vitamines et d'autres substances alimentaires déterminent sur le développement des infections et des tumeurs malignes montrent qu'au régime alimentaire suboptimal et optimal s'oppose le régime superoptimal.

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Vortrag, gehalten am 23. Oktober 1946 in der Naturforschenden Gesellschaft in Basel.     

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 den Phytoöstrogengehalt einiger Pflanzen

Summary The quantity of phyto-estrogens in red clover, hop, peas, and cabbage was estimated by titration on castrated female rats and infantile mice. The level of phytoestrogens was as follows: in hop 1050–2000/kg, in peas 4–6/kg, in cabbage 24/kg, and in red clover 6–9/kg. The author supposes that the sexual disorders described byRosenberger ¹⁴ in cows fed with cabbage, can be explained by the presence of phyto-estrogens in this plant.     

Über die Basizität der Knochenmineralien

Summary The inorganic salts of bone tissue are, owing mainly to their contents of tertiary phosphate, strongly basic. A quantitative evaluation of these base equivalents can be performed through simple titration with acid after solution of the bone salts in a chelating agent (e.g. citrate). Referring to an endpoint of pH 7.40, one finds that per mMol Calcium 0.82 mEq base is set free. With regard to acid-base metabolism, the results indicate that bone phosphate, whichin vivo can be mobilised through osteoclastic resorption, forms a remarkably big base reserve in the animal organism.

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Die vorliegende Arbeit wurde mit der Unterstützung des Schweiz. Nationalfonds zur Förderung der wissenschaftlichen Forschung durchgeführt.     

Über das Problem der Welkekrankheiten bei Pflanzen

Summary Lycomarasmin is a plasma poison produced byFusarium lycopersici Sacc., the pathogen of tomato wilt. In a dilution of 10^–2 and 10^–3 mol it causes a pathological wilting of tomato plants and usually disturbs their water balance; in a dilution of 10^–4 mol it only disturbs the latter.In the present paper, we develop the theory that in sufficient concentration lycomariasmin damages or destroys thesemipermeability of the plasma boundary layer.In a dilution of 10^–2 and 10^–3 mol of lycomarasmin the semipermeability of the plasma membranes iscompletely destroyed. Thus on the one hand the conditions for osmotic pressure disappear and irreversible pathological wilting appears, and on the other hand cellular fluid passes into the transpiration current of the cell-membrane and leads to a momentary excess humidity, particularly in the leaf-tissues, and thus also to a momentaryexcess transpiration.The water-deficit regularly observed in wilt-literature is therefore not the cause of pathological wilting but, just as the wilting itself, a consequence of the distruction of the semipermeability of the plasma boundary layer.In a dilution of 10^–4 mol lycomarasmin apparently only affects the permeability of the exterior plasma boundary layer forwater, but not for sugars etc. Therefore it only produces an excess of fluid in the leaf tissues and thus an excess transpiration, but no definite inactivation of the plasma membrane and therefore also no pathological wilt.