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.     

Novel rearrangement of purines

Summary 6-Trichloromethyl-9-methylpurine (1) rearranges to 6-dichloromethyl-9-methyl-8-oxopurine (2) in aqueous mild acidic solution. The rearrangement is rationalized in terms of a reaction involving protonation, covalent hydration, prototropic equilibrium and/or a hydride transfer. An alternative mechanism involving a positive halogen compound and hypochlorous acid as an intermediary is also proposed. Compound1 condenses with 4,5-diaminopyrimidine to give the purine-pyrimidine Schiff base pair4.Acknowledgments. We are deeply indebted to Professor S. Cohen of the Sackler School of Medicine, Tel Aviv University (Ramat Aviv, Isreal) for his advice and encouragement. Support of this research by the Israel Cancer Association, the Ber-Lamsdorf Foundation Switzerland Israel and by the Advancement of Mankind Foundation, is gratefully acknowledged. We thank Proff. D. Arigoni and A. Eschenmoser, ETH Zürich, for their valuable proposals and comments on the mechanism of the rearrangement.     

Preformed azulene pigments ofLactarius indigo (Schw.) Fries (Russulaceae,Basidiomycetes)

Summary The structure of a new naturally-occurring azulene, 1-stearoyloxymethylene-4-methyl-7-isopropenylazulene, obtained from an acetone extract of the blue mushroomLactarius indigo, has been determined by chemical and spectral methods.This paper is dedicated to Prof. André Dreiding, Zürich, on the occasion of his 60th birthday.     

Experiments on sexual isolation between Chilean and European strains ofDrosophila subobscura

Summary Males and females of Chilean strains ofDrosophila subobscura exhibit a pronounced tendency toward homogamic mating. This tendency shows a clear relation to the distance between the geographic localities from which the respective strains came. Nevertheless, when the Chilean flies are confronted with European strains, the ethological isolation is observed in some cases but not in others, depending on the geographic origin of the strains.Acknowledgments. This work has been partially supported by grants from the Univ. of Chile (Project B 729-8345) and PNUD/UNESCO (RLA 78/024). We are most grateful to Prof. D. Sperlich of the University of Tübingen who provided theD. subobscura strains from Tübingen and Sicily, and Prof. A. Prevosti from the University of Barcelona and R. de Frutos from the University of Valencia who provided the strains of Mallorca and Almería. We are finally obliged to Mr E. Zárate for his technical assistance.     

Inhibition of firefly bioluminescence by scavengers of singlet oxygen,superoxide radicals and hydroxyl radicals

Summary The participation of highly energetic oxygen species in the ATP-induced bioluminescence of a firefly-extract has been investigated. The inhibition of light emission by a variety of specific scavengers suggests that singlet oxygen, superoxide radicals and hydroxyl radicals are important intermediates in the firefly bioluminescence reaction.Acknowledgments. I thank Prof. R. Bachofen, Institut für Allgemeine Botanik, Abteilung Mikrobiologie, Universität Zürich, Switzerland, in whose laboratory most of these studies have been performed, for his cooperativity. Financial support by the Deutsche Studienstiftung is gratefully acknowledged.     

Hemolymph proteins in an ascitic condition,induced by lethal1(3)gl tumorous tissue inDrosophila hydei

Summary Drosophila hydei larvae homozygous for the gene1(3)gl may survive to the age of 3 weeks, become bloated and be incapable of metamorphosis. Wild-type flies after the injection of a fragment of the1(3)gl disc, which has been previously culture in vivo for 40–500 days, also become bloated (ascitic reaction). In the hemolymph of both the advanced1(3)gl larvae and ascitic adult hosts the accumulation of a specific protein is observed.Acknowledgments. This work was supported by the Swiss National Science Foundation under Grant No.3.792-0.76 and the Georges und Antoine Claraz-Schenkung. We thank Prof. H. Gloor, University of Geneva, and Prof. P.S. Chen, University of Zürich, for advice and criticism.     

α-Adrenoceptor blocking action of hymenin,a novel marine alkaloid

Summary In the rabbit isolated aorta, hymenin (10^–6 M) a novel marine alkaloid, caused a parallel rightward shift of the dose-response curve for norepinephrine without affecting that for histamine or KCl, suggesting that hymenin is a competitive antagonist of -adrenoceptors in vascular smooth muscles.Acknowledgments. We thank Ms A. Kajiwara and Ms M. Hamashima of this institute for their technical assistance, and Prof. Y. Hirata of Meijo University for his encouragement.     

Zur Biosynthese des Plumierids

Summary It has been shown that the leaves ofPl. acutifolia incorporate acetate-1-¹⁴C and mevalonate-2-¹⁴C specifically for the formation of the aglycone moiety of plumieride.

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Wir danken dem Schweizerischen Nationalfonds sehr für die Unterstützung der Arbeit, Herrn Dr.J. Würsch (F. Hoffmann-La Roche & Cie., Basel) für markiertes Mevalonsäure-lakton und Herrn Prof.D. Arigoni (Zürich) für interessante Diskussionen.     

Pattern of membrane invaginations at the surface of smooth muscle cells of rabbit arteries

Zusammenfassung Mit Hilfe der Gefrierätzung wurde die Oberfläche glatter Muskelzellen von Kaninchenarterien (A. ilica) dargestellt. Die Aufsicht zeigt ein charakteristisches Muster von parallel zur Zellachse verlaufenden Streifen, welche aus einer bis mehreren Reihen einheitlich grosser Membraneinstülpungen (Caveolae intracellulares) bestehen.

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The authors wish to thank Prof.H. Moor, Department of General Botany, Swiss Federal Institute of Technology, Zürich (Switzerland), for advice and freeze-etching facilities.     

Effect of diabetes on the vertebral column of rats and its modification by estradiol

Summary In vertebrae of genetically selected sucrose-fed diabetic rats a statistically significant bone deficit was found after diabetes had been present for about 8 months. No osteopenia was observed in diabetic rats following treatment with estrogenic hormone for 5–7 months. The development of osseous centers in the end plates of the vertebrae was retarded in diabetic rats, but was about normal in diabetic rats given estrogen.—No differences were noted in the growth zones or in the tendency to develop articular lesions in rats of the various groups. Possible differences in the amount of GAG in intervertebral discs of diabetic and non-diabetic rats respectively await further confirmation.These investigations were aided by grant No. 2 RO1 EYO 1837-03, of the Institute of Arthritis and Metabolic Disease, National Institutes of Health, Bethesda, Maryland, USA.We are indebted to Professor Dr J. Rüttner, Institute of Pathology, University of Zürich, for his permission to use the calculator.     

Über die Sekretion saccharosespaltender Transglukosidasen im pflanzlichen Nektar

Summary The phloem sap ofRobinia Pseud-Acacia contains only sucrose and does not possess invertase activity. A sucrase is, however, present in nectar collected fromRobinia flowers: this enzyme identified as a transglucosidase, liberates greater amounts of fructose than of glucose from sucrose. Enzymic activity apparently commences 2–5 days before the flowers are fully open.

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Die vorliegenden Untersuchungen erfolgten im Rahmen der Arbeitsgemeinschaft Prof. Dr.A. Frey-Wyssling, Zürich, und Dr.A. Maurizio, Bern, mit Unterstützung der Fritz-Hoffmann-La-Roche-Stiftung zur Förderung wissenschaftlicher Arbeitsgemeinschaften in der Schweiz.     

Characterization of the host-specific toxins produced byHelminthosporium sacchari,the causal organism of eyespot disease of sugarcane

Summary Investigation of the host-specific toxin complex fromH. sacchari has led to the isolation of 3 isomeric glycosidic components C₃₉H₆₄O₂₂, each active at 2×10^–11 moles. The 3 isomers consist of 4 galactose units linked to an aglycone residue C₁₅H₂₄O₂.Acknowledgments. The Boyce Thompson-Cornell group thanks J.F. Rissler, University of Maryland, A.K. Bose, Stevens Institute of Technology, R. Barker and A. Serriani, Cornell University, and C. Grinnalds and J. Golay, Boyce Thompson Institute for help with various aspects of this work. Supported in part by a grant to V.M. from the US Department of Agriculture (8100720). The Zürich group thanks Dr G.A. Strobel, Department of Botany and Microbiology, Montana State University, Bozeman, for supplying a potent toxin-producing strain (M 36), a susceptible clone of sugarcane (51 NG 97), and a reference sample of helminthosporoside, Dr. K. Hostettmann and Mme M. Hostettmann-Kaldas, Pharmazeutisches Institut ETH Zürich, for assistance in developing the DCC separation and Sandoz A.G., Basel, for financial support.     

Benzamide potentiation of behavioral apomorphine-induced effects; mechanism involved

Summary A new N-pyridinyl benzamide was found to potentiate strongly the effects of apomorphine on the motility of reserpinized mice and on circling behavior. Since dopaminergic agonist activity could not account for this potentiation, involvement of-adrenergic agonist activity provided the only consistent explanation.Acknowledgments. We wish to thank Mr A. Decoodt for his excellent technical assistance and the Laboratoire de Chimie Therapeutique (Prof. Le Baut), Université de Nantes, for providing samples of N-PCB.     

A microbial metabolite of TCDD

Summary In the present study we describe the occurrence of a metabolite of TCDD, which arose in several microbial cultures after long term incubation. The polar metabolite amounted approximately 1% of the input material, and was found to be a hydroxylated derivative of TCDD.The work was supported by a grant from the Swiss Federal Government to R.H. and M.P. We thank Dr K. Grob, GC-Laboratory ETH Zürich, Dübendorf, Switzerland, for providing the highly inert column used in this work, and H.-R. Buser, Swiss Federal Research Station, Wädenswil, Switzerland, for his help in the analysis of the¹⁴C-TCDD.     

The effect of formaldehyde on the mutagenic action of X-rays inDrosophila

Zusammenfassung Vor einer Röntgenbestrahlung, deren Dosis von 1700 bis 2200 r variierte, wurdeDrosophila-Männchen Formalinlösung in schwacher, submutagener Konzentration injiziert. Es zeigte sich, dass im Vergleich zu den Kontrollen, welche nur bestrahlt wurden, die Mutationsrate nach Formalin-Vorbehandlung signifikant gesteigert war. Dabei wurden spätere Entwicklungsstadien der Spermatogenese erfasst als nach einer Vorbehandlung mit Zyanid, Azid und einem organischen Peroxid; bei reifen Spermatozoen liess sich jedoch keine Zunahme der Mutationsrate feststellen. Die Befunde weisen darauf hin, dass ein erhöhter Gehalt an organischen Peroxiden in den vorbehandelten Zellen die Chromosomen empfindlicher macht für die mutagene Wirkung der Röntgenbestrahlung.

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This paper is dedicated to Prof. Dr.Jacob Seiler, Zürich, on the occasion of his 70th birthday.     

C-banding pattern on the chromosomes of the Japanese house shrew,Suncus murinus riukiuanus,and its implication

Summary The C-band on the chromosomes of the Japanese house shrew,Suncus murinus riukiuanus (Insectivora), was studied. Various types of C-banding pattern were found in the genome of this subspecies. Such banding patterns could be useful for an understanding of autosome and sex-chromosome polymorphisms withinS. murinus.Acknowledgment. The authors are very grateful to Prof. T. Wasano of Fukuoka University for his encouragement, Dr K. Ogawa of Fukuoka University, the Nohara family for help in collecting specimens, and Prof. E.W. Jameson, Jr, University of California, Dr J.W. Bickham and his students of Texas A & M University for comments.     

AnAnolis skin melanophore assay suitable for photoaffinity labeling studies with α-MSH

Summary Visual determination of MSH-induced pigment migration in melanophores of small pieces ofAnolis carolinensis skin is standardized by first measuring photoelectrometrically the change in reflection/transmission of the whole dorsal skin in response to different hormone concentrations. This method allows the rapid and precise recording of time-response curves after photoaffinity labeling of MSH receptors or of dose-response curves of large series of synthetic compounds.Acknowledgments. We wish to thank Ms V. Jäggin, Ms C. Schulthess and Ms G. van Hees for excellent technical assistance, Dr. R. Andreatta, Ciba-Geigy AG, Basel, for his generous gift of -MSH and Prof. A Pletscher for his continuous interest. This work was supported by the Swiss National Science Foundation.     

Die Alkaloide im Stoffwechsel der Pflanze

Ohne Zusammenfassung10. Paul-Karrer-Vorlesung, gehalten am 19. Juni 1968 in der Aula der Universität Zürich.     

Vagusstoffe

Ohne ZusammenfassungNach einem Vortrag vor der Chemischen Gesellschaft Zürich, 2. Juli 1945.     

Physiologische Instinktforschung

Ohne ZusammenfassungZusammenfassung von vier an der Universität Zürich, Januar 1948, abgehaltenen Gastvorlesungen.