Zum physiologischen Potenzbegriff

Summary Based on the literature and the author's own research on general and comparative heart physiology, the term of Automaty-Potentiality is discussed and differentiated. Adouble term Automaty-Dominance/Automaty-Latence is proposed as serviceable.     

Zum Mechanismus der Propandioldehydrase-Reaktion

Summary Investigation of the propanediol dehydrase reaction with¹⁸O-labelled substrates indicates that the conversion of propane-1,2-diol to propionaldehyde involves transfer of the oxygen atom from C-2 to C-1. The dehydration of the so formed propane-1,1-diol is sterically controlled by the enzyme.     

Zum Wirkungsmechanismus des Histamins

Summary With the aid of the tensiometer, it can be proved that histamine reacts in a specific manner with primary phosphoric acid esters. This proof is brought about by strongly increasing the capillary activity of cetyl phosphate by histamine on the interface chloroform water. The mechanism of this reaction is discussed. Simple secondary phosphoric acid esters and bi-secondary phosphoric acid esters are not influenced under the same conditions. A pronounced antagonistic effect of calcium ions antihistamine compounds may be proved with the same assays.The point of attack of these compounds is the phosphate and not the histamine. The results of the tests confirm the assumption that the mode of action of the histamine and of the antihistamine compounds is connected with primary phosphoric acid esters.     

Zum Reaktionsmechanismus von Oxydasen

Summary The reactivity of copper(I)-complexes towards molecular oxygen in relation to some copper containing enzymes has been studied. The oxydation of simple amine-complexes proceeds at a rate of about 10³–10⁴ Mol^–1 Lt Min^–1. Replacing the amine by amides and peptides has a strong retarding effect. A copper(I)-cysteine complex exhibits the interesting property of adding O₂ reversibly.     

Zum Problem der menschlichen Stammesgeschichte

Ohne Zusammenfassung     

Zum Mechanismus derβ-Lysin-Mutase-Reaktion

Summary Using tritium labelled substrates it is shown that in the rearrangement of (S) --lysine to 3,5-diaminohexanoic acid catalysed by-lysine mutase a stereospecific hydrogen migration from C-5 to C-6 of the substrate occurs. When the reaction is carried out in the presence of [5-³H]-coenzyme B₁₂, the heavy isotope is transferred both to C-6 of 3, 5-diaminohexanoate and to C-5 of-lysine. In the latter the labelled atom occupies the same diastereotopic position as the H atom that is transferred to C-6 of the product.     

Zum Wirkungsmechanismus des chemischen Strahlenschutzes

Summary Possible mechanisms for the action of radiation damage inhibiting substances, especially 1-hydrazinophtalazine, are discussed. From experiments, designed for simulation of radiated aqueous systems, it can be concluded that this inhibiting action is caused by the special redox-kinetic behaviour of the compound towards strong oxidizing agents.     

Urethan als Follikulinantagonist

Ohne Zusammenfassung     

Zum Chemismus der Kadmiumreaktion im Blutserum

Summary The authors have recently introduced a new reaction, which allows to estimate the lability of the Serum Proteins. It is measured by the turbidity caused by a solution of CdSO₄. It is shown by electrophoresis before and after the CdSO₄-reaction has taken place, that the turbidity is not originating from any single protein fraction, but from all of them, though to a different degree.     

Zum Problem der Nahrungspflanzenwahl der Aphiden

Summary OnAllium schoenoprasum L. andPoa pratensis L., two species that do not belong to the host plants ofMegoura viciae Buckt., this aphid pierces the sievetubes as in its natural host,Vicia faba L. In none of these plants do the aphids take up³²P from the parenchyma. Presumably phloem-sucking aphids probe, before finally settling in the sieve-tubes of the plant, to recognize the quality of the plant.     

Schnee als kristallines Aggregat

Summary The newly fallen snow exhibits in its large variety of form all the changes in the atmospheric conditions (temperature, moisture, wind), and is a divided, labile matter. After the deposit, the cubic weight increases through the dead weight and the intercrystalline forces. These latter are closely connected with the metamorphosis of the crystals of newly fallen snow, basing on a stability of form. It appears that the snow crystal is covered with a superficial layer of fluid-like properties, and that the surface expansion is responsible for the first phase of the transformation. For the further change into the coarse grained old snow temporal and local differences are necessary. This has been found by observation of nature and of laboratory experiments, and in both cases were the results the same. The snow aggregate possesses, as a whole, a remarkable plasticity; the relations of this latter to the crystal plasticity is, at present, being examined by means of deformation tests. Of the characteristics of the plasticity of crystals a certain firmness and recovery can be observed partly, however, obscured by an elastic after-effect up till now never observed in snow. Of a slow limit there is only a suggestion. Besides mechanical mensurations, microscopic tests are being made on thin grinding plates to get at the individual proceedings.     

Zum Vorkommen von Thiothreonin im Pflanzenmaterial

Summary In extracts of H₂ ³⁵S gased pea seedlings, a radioactive substance has been revealed by thin layer chromatography which showed the same chromatographic properties as thiotheronine.     

Zum Vorkommen von RNS im Nervenfaserbereich

Summary The incorporation of 3H-uridine into the RNA of the perikaryal and fibrous region of the optic tectum of the fish brain was investigated by means of radioautography after incubation times of 11 min to 96 h. There is no transport of RNA from the cell body to the nerve fibres. After RNase-treatment 90% of perikaryal RNA-labelling is washed out, but only a very small amount of the previous very few labelling of the nerve fibres.     

Mechanische Festigkeit als Elektroneneffekt

Summary TheBrinell hardness ofHume-Rothery alloys depends on their electron concentration in the same way as do catalytic activation energy and electric resistivity. A wave-mechanical theory of hardness, based on the more or less total completion of theBrillouin-zones, is proposed.     

Antibiotika als pflanzliche Plasmagifte

Summary The toxic action oflycomarasmine (a wilting agent produced byFusarium lycopersici Sacc., the causal organism of tomato-wilting) and ofpatulin (clavacin, an antibiotic produced byPenicillium patulum and by some other fungi) on some test-objects is studied (anthocyanin-test with red turnips, plasma-streaming test withSpirogyra etc.). Both substances are able to destroy for instance the semipermeability of the plasma boundary layer; but patulin proves to be more toxic for these objects than lycomarasmine, the specific poison of the tomato wilting disease.     

Zum Vorkommen von Maltose in vegetativen Pflanzenteilen

Summary Some older results on the occurrence of maltose in higher plants have been verified; semiquantitative estimations were made. Also maltose is detected inAconitum lycoctonum and inEquisetum arvense.     

Schwefel als Ligandatom in Chelatkomplexen

Summary The hitherto unknown compounds 5-(2-pyridyl)thiazole, 2-(2-thienyl)pyridine and methyl--picolyl sulphide have been synthesized. The structure of all three substances allows the formation of a chelate ring with N and S as ligand atoms. 5-(2-Pyridyl)thiazole yields with Fe²⁺ at a pH of 2.5 a significant change in absorption, which is attributed to chelate formation.     

Catechine und Hydroxy-flavandiole als Gerbstoffbildner

Summary From the ranks of the colourless hydroxyflavans, four differenthydroxyflavan-3-ols(catechins and epi-catechins), as well as eight hydroxyflavan-3,4-diols, have so far been encountered in nature. These substances are also procurable by synthesis. On treatment with hot water or dilute acids, they are easily converted into soluble tannins or insoluble phlobaphenes. The mechanism of the self-condensation is explained using catechin via the isolation of a dimerie product. A probable path for the self-condensation of the diols has been indicated. In contrast to the products of their self-condensation, the monomeric polyhydroxyflavans are not real tannins. A particular accumulation of phenolhydroxyl groups in the molecule, the tendency to form supersaturated solutions and low solubility in water in the — generally not attainable — crystalline state are prerequisites for tanning properties. In nature, the self-condensation of polyhydroxyflavans proceeds (e. g. in the wood ofAcacia catechu or in Quebracho Wood) without the assistance of enzymes. Dehydrogenative polymerisation occurs with formation of brown or red phlobaphenes (e.g. in cocoa beam) which are generally insoluble.