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.     

Aus der Chemie der Naturstoffe

Summary This lecture was held in Zürich to commemorate the 70^th birthday of Prof.Paul Karrer; it briefly outlines his life-work as a scientist and then reviews, in greater detail, some of his important work in various fields: vegetable dyestuffs (carotenoids), vitamins (particularly vitamins A, E and K) and curare alkaloids.As is the purpose of this lecture, a review is also given of the author's own work: ergot alkaloids and their derivatives; cardiac glycosides of squill, digitalis etc.; and finally, the most recent results of research on chlorophyll — the crystallization of natural chlorophylla andb after many years of endeavour.

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ErstePaul-Karrer-Vorlesung, gehalten im Rahmen der öffentlichen Feier zum 70. Geburtstag von Prof.Paul Karrer, am 25. April 1959 in der Aula der Universität Zürich.     

Zur Frage der Mesonenmassen

Summary The measurement of meson masses in the cosmic radiation with a slowly expanding wilson chambre indicates mesons of different masses. There are at least two different masses, one between 100m ₀ and 200m ₀, and the other exceeding 200m ₀.     

Über die Rolle der Stabilitätsbetrachtungen in der Entwicklung der Bohrschen Atomtheorie

Ohne Zusammenfassung Vorgelegt von L. Rosenfeld     

Zur Biosynthese der C9–10-Einheit der Indolalkaloide

Summary After administration of various C₂-compounds as well as leucine-2-¹⁴C toCatharanthus roseus shoots and glycine-2-¹⁴C toStrychnos nux vomica plants no specific incorporation into the non-tryptophan C_9–10 moiety of indole alkaloids was observed. The results indicate that glycine-2-¹⁴C is transformed into serine and is incorporated via tryptophan into strychnine.     

Disk-elektrophoretische Untersuchungen der Serumproteine europäischer Eschsen der Familien Anguidae und Lacertidae

Summary Serum proteins ofLacerta v. viridis, L. v. meridionalis, L. trilineata, L. agilis, L. vivipara, L. taurica, L. muralis, Ophisaurus apodus, andAnguis fragilis were separated by polyacrylamide disc electrophoresis. Among the lacertids,Lacerta viridis andLacerta trilineata show greater similiarities.Ophisaurus apodus andAnguis fragilis are characterized by praealbumins.     

Zur Stereochemie der Propandioldehydrase-Reaktion

Summary Propanedioldehydrase is shown to convert both (+)-(S)-2-²H-propanediol,3, and (–)-(R)-1-²H₂-propanediol,5, to specimens of deuterated propion-aldehyde, for which the (S)-configuration has been established. Thus, in the propanedioldehydrase reaction migration of hydrogen atoms from C–1 to C–2 always occurs with inversion of configuration.     

Zur Geschichte der Entdeckung der 230 Raumgruppen

Ohne Zusammenfassung Vorgelegt von J. E. Hofmann Nach einem Vortrag im 11. Internationalen Kolloquium zur Problemgeschichte der Mathematik am 19. September 1966 im Mathematischen Forschungsinstitut in Oberwolfach.     

Über das Vorkommen und die Natur der Cholinesterase der Schlangengifte

Summary An enzyme that hydrolyzes acetylcholine is present in the dried venoms of 19 species of theColubridae (9 genera), but not in the venoms of more than 20 species of theViperidae (7 genera). The enzyme behaves like the e-Cholinesterase of the mammalian tissues.     

Über den Zusammenhang der Carnotschen Theorie mit der Thermodynamik

Ohne Zusammenfassung Vorgelegt von M. Klein     

Die physikalische Kieme der Wasserinsekten

Summary The air stores carried by a number of aquatic insects have: a) a hydrostatic function (Brocher, Oortwijn-Botjes, Thorpe, andCrisp); b) the function of an oxygen store (Ege, de Ruiter et al.) and c) the function of a physical gill (Strauss-Durckheim, Ege, etc.). The fact that oxygen is taken up from water with the aid of an air bubble was demonstrated forNotonecta by comparing the life time of insects with and without physical gill (while replenishing the oxygen store from the air was prevented) byEge, and forCorixa byPopham, whileVlasblom determined the oxygen uptake from water with and without air bubble forNotonecta, Naucoris, Corixa, Sigara andNepa. Nepa andSigara can take up considerable quantities of oxygen by cutaneous respiration.During the summer, the gill function of the air store ofNotonecta andNaucoris is of importance only when a water current passes along the animal, caused by ventilation movements of the legs (de Ruiter et al.). At low temperatures, however, the metabolic rate is so low that in many instances the physical gill provides the oxygen required without ventilation movements.An apparatus for the simultaneous determination of oxygen uptake from air and water (Wolvekamp andVlasblom) gave results that provided a means of evaluating the importance of the physical gill function.In some cases, the air store, although in direct contact with the water, does not need to be replenished. InAphelocheirus andElmis, the negative pressure in the bubble, caused by oxygen consumption and the diffusing out of part of the nitrogen, is compensated for by the mechanical resistance of a feltwork of thin hairs and the surface tension of the boundary layer of the water (Thorpe andCrisp). In the African beetle,Potamodytes, the unprotected air bubble is permanent because the strong river currents produce a lowered pressure around the animal according toBernoulli's principle (Stride).     

Geschichte der Wellenmechanik

Ohne Zusammenfassung Vorgelegt von B. L. van der Waerden     

Untersuchungen zum Verhalten der Ameisenmännchen während der imaginalen Lebenszeit

Summary Marking experiments with the tracer isotopes P³² and I¹³¹ and other behaviour experiments on ant males (Camponotus andFormica) showed that the males live during the imaginal life in several phases: I = social phase; II = rest phase; III = sexual phase; IV = death phase.     

Cytostatischer Wirkungsmechanismus der Methylhydrazine

Summary Cytostatic active methylhydrazine derivatives split off formaldehyde after mild dehydrogenation with potassium hexacyanoferrate (III). It is suggested that the primary formedazomethines andN-hydroxymethylderivatives participate in cytostatic efficacy by their alkylating ability (aminomethylation). Formaldehyde alone and its condensation products with hydrogen peroxide especially bis-hydroxymethylperoxide may exert cytostatic effects too.     

Motive und Probleme der Arithmetisierung der Mathematik in der ersten Hälfte des 19. Jahrhunderts — Cauchys Analysis in der Sicht des Mathematikers Martin Ohm

Ohne Zusammenfassung Vorgelegt von C. J. Scriba     

Bestimmung der Zahl aktiver Zentren der Acetylcholinesterase in motorischen Endplatten

Summary ³²P or¹⁴C-labelled diisopropyl-fluoro-phosphate (DFP) was bound to endplates of mouse diaphragms by incubation. The number of molecules was determined by densitometric measurement of autoradiographs. One endplate contains 2.4·10⁷ active centres for acetylcholine, blocked by DFP. The turnover time for acetylcholine is very short: 15µsec.     

Die Algebra der Babylonier

Ohne Zusammenfassung Vorgelegt von B. L. van der Waerden     

Differenzierung der Wirkung von Desinfizienzienin vitro

Summary In testing the effects of various disinfectants onStaphylococcus aureus andBact. coli in respiration experiments two greatly differing types of action were found whose variations are described by two characteristic respiration curves.Some disinfectants act onStaphylococcus according to one type of action and onBact. coli according to the other.Various disinfectants act on the same bacteria partly according to one type of action and partly according to the other.     

Unterschiede in der Carbohydrasenausrüstung der Entwicklungsstadien vonMelolontha melolontha L.

Summary The activities of-xylosidase,-xylanase and inulinase were demonstrated only in the tissues of the larval intestinal canal which also split galactose and arabinose from certain hemicelluloses and-galactan. Several other carbohydrases originating from microorganisms were also detected only in the content of the larval alimentary tract.

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Ein Teil der Arbeit wurd am Institut für Obstbau der Biologischen Bundesanstalt Heidelberg ausgeführt.     

Zur Kenntnis der Vernetzungspolymerisation

Summary The intrinsic viscosity of cross-linked copolymers of styrene andm,m-divinyl-azobenzene orp-divinyl-benzene was measured for different degrees of polymerization.It has been shown that the two vinyl groups of the cross-linking agent are taken up by growing chains, each one independently of the other.The number of cross-linkages is not absolutely identical with the number of the molecules of divinyl compound, but is determined by the magnitude of the various rates of growth.