During the early 1950's there appeared reports, from time to time of the presence among the products elaborated by actinomycetes of antifungal antibiotics which exhibited very similar and very characteristic multipeaked ultraviolet absorption spectra. In 1954, with a good number of examples on record, these spectra were analyzed and identified as those of straight-chain conjugated polyenes, comprising tetraenes, pentaenes, hexaenes and heptaenes (85, I30). These antibiotics have since been commonly referred to as the polyene antifungal antibiotics to distinguish them from a host of other miscellaneous antibiotics which also have antifungal properties. Within the next few years, reports of discoveries of new members of this class multiplied rapidly, and almost sixty are now known. Unquestionably, a number of these will eventually be found to be identical with others, as has already happened in several instances: for example, the tetraene "tennecetin" proved to be a rediscovery of pimaricin (34), and in the methyl- pentaenes "moldcidin E" has been identified with pentamycin (83), and "lagosin" appears to be indistinguishable from fungichromin (22). Those that have been purified have turned out to be of fairly high molecular weight (ca. 700-1300) and all appear to be substances of rather similar molecular structure. So far only three, pimaricin, fungi- chromin (lagosin) and filipin, have been structurally elucidated.

This volume contains the Proceedings of the 25th Mosbach Colloquium, the general theme of which is the Biochemistry of Sensory Functions. It was intended, continuing the silver-tradition of these Colloquia, to provide the uninitiated biochemist with an insight into the current status of a line of research in Molecular Biology which, more than many other fields in Biochemistry, has maintained its contacts with and respect for Physiology. The speakers were asked to attempt to outline their topic sufficiently to define the fundamentals and to build up upon this basis the more sophisticated details of their own studies. It is for the reader to evaluate how well both organizer and participants 1 have attained this end * These Proceedings not only mirror the hubs around which several groups of scientists wheel but may also serve as a source of literature references and for the advanced student as an introduction to this highly up-to-date branch of Biochemistry, although no index is provided as the table of con- tents is considered sufficient to locate most of the s,

Contents/Information: N.P. Johnson, J.-L. Butour, G. Villani, F.L. Wimmer, M. Defais, V. Pierson, Toulouse, France; V. Brabec, Kralovopolska, CSSR: "Metal Antitumor " "Compounds: The Mechanism of Action of Platinum Complexes " "Pertaining to the Design of Anticancer Agents"B.K. Keppler, M. Henn, U.M. Juhl, M.R. Berger, R. Niebl, Heidelberg; F.E. Wagner, Garching, FRG: "New Ruthenium Complexes for the " "Treatment of Cancer"G. Mestroni, E. Alessio, Trieste, M. Calligaris, Pavia, Italy; W.M. Attia, Ismailia, Egypt; F. Quadrifoglio, S. Cauci, Udine, Italy; G. Sava, S. Zorzet, S. Pacor, C. Monti-Bragadin, M. Tamaro, L. Dolzani, Trieste, Italy: "Chemical, Biological and Antitumor Properties of " "Ruthenium (II) Complexes with Dimethylsulfoxide"N. Farrell, Burlington/VT, USA: "Metal Complexes as Radiosensitizers"S.C. Srivastava, L.F. Mausner, M.J. Clarke, Upton/NY, and Chestnut Hill/MA, USA: "Radioruthenium-Labeled Compounds for " "Diagnostic Tumor Imaging"P. Kopf-Maier, Berlin, FRG: "The " "Antitumor Activity of Transition and Main-Group Metal " "Cyclopentadienyl Complexes"E.V. Scott, G. Zon, L.G. Marzilli, Atlanta/GA and Foster City/CA, USA: "NMR Relaxation " "Footprinting: The ACr(NH3)6U3+ Cation as a Probe for Drug " "Binding Sites on Oligonucleotides"J.E. Schurig, H.A. Meinema, K. Timmer, Wallingford/CT, USA; B.H. Long, A.M. Casazza, Zeist, NL: "Antitumor Activity of " "BisABis(Diphenylphosphino)Alkane and AlkeneU Group VIII " "Metal Complexes"M.E. Heim, H. Flechtner, Mannheim; B.K. Keppler, Heidelberg, FRG: "Clinical Studies with Budotitane -" "A New Non-Platinum Metal Complex for Cancer Therapy""

Die Befruchtung spielt eine bedeutende Rolle im Entwicklungsgang der Organismen. In ihrem Verlauf werden die Gametenkerne, und damit das genetische Material zweier Individuen, vereinigt. Durch die Meiose (Reduktionsteilung) wird der Ausgangszustand wiederhergestellt, jedoch in einer solchen Weise, daB die elterlichen Erbfaktoren in den verschiedensten Kombinationen neu verteilt werden konnen. Die Beob- achtung von Befruchtungsvorgangen zeigt, daB der eigentlichen Ver- schmelzung der Geschlechtszellen Reaktionen vorausgehen, an denen offensichtlich chemische Wechselwirkungen beteiligt sind. Besonders deutlich lassen sich solche stoffiichen Wechselwirkungen bei niederen Pflanzen beobachten, bei denen beispielsweise Geschlechtsorgane nur gebildet werden, wenn der entsprechende Partner oder Filtrate seines Kulturmediums vorhanden sind. In anderen Fallen kann man beobachten, daB Geschlechtsorgane durch Luft oder Wasser gerichtet aufeinander zu- wachsen oder, daB freibewegliche mannliche Gameten sich gezielt zu stationaren weiblichen Gameten hinbewegen. Solche biologischen Reak- tionen sind auBerordentlich empfindlich, und die Konzentration der beteiligten Stoffe ist entsprechend gering. Dies macht die Ansammlung von gentigenden Mengen fUr die StrukturaufkIarung zu einem auBerst mtih- samen Unternehmen. Obwohl auch in der alteren Literatur zahlreiche Hinweise auf chemische Wechselwirkungen zwischen Sexualpartnern vor- handen sind (42, 43), konnten bisher erst wenige derartige Geschlechts- stoffe identifiziert werden. Erst die hochleistungsnihigen modernen Ana- lysenmethoden, wie Massen- und Kernresonanz-Spektroskopie, haben hierbei die Forschung wesentlich vorangetrieben. Man kennt heute die Molekularstruktur von vier Sexualhormonen, die nunmehr auch synthe- tisch zuganglich sind.

Bio-organic Chemistry has corne of age - the sign of this is the start of a new series of Lecture Notes that are the product and substrate of spreading this line of modern knowledge among graduate students and research workers in such fields as mechanistic biochemistry, bio mimetic organic chemistry, biotechnological application of enzymology, to name only a few examples of how many frontiers are opened and borders lifted - just at. the time when the demand for a'''Synthetic Biology" and "Molecular Biotechnology" is increasing - fields that have been neglected for (too) long a time by "classical" chemists in curricula and imagination. We hope that through this first volume, which pOints in the several directions mentioned above, the profile of the undertaking will become clear and that it will find resonance among the scientific community interested in the thoughtful application of chemical and physical con cepts to biochemical and molecular-biological problems."

Ihre Biosynthese erfolgt aus kleinen Bausteinen, ahnlich derjenigen der Fett- sauren. Ihre Wirkungsweise als Signalstoffe wird in der spezifischen Bin- dung an Rezeptorproteine in der Gameten-Membran vermutet, die dadurch ihre Raumstruktur andern und somit einen Impuls auslosen. Dieser wird in "Richtung" oder "Geschwindigkeit" umgesetzt, so daB die Gametenzelle topotaktisch oder phobotaktisch das Ziel, die Duftstoffquelle, erreicht. Diese kann durch einen kiinstlichen Duftstofftrager ersetzt werden, durch den man die wahrnehmbare Grenzkonzentration ermitteln kann. Darauf begrundet sich der quantitative Nachweis, der fur die Erforschung des Wirkmechanis- mus, als Modell fur die Vorgange beim Geruchs- und Geschmackssinn, notig ist. Summary Sex hormones play an important role in the development and differentia- tion of sexual determination and reproduction; although research in this field has been largely confined to animal studies, these phenomena find their analogs in plants as well. Algae, mosses and fungi are lower plants that are we11 suited for studying these chemical agents and their influence on respective "targets". Sexual determinants and attractants have recently been isolated, identified, and their biological properties characterized. A termone (sex determining hor- mone) from the mold Mucor determines the gender of sti11 undifferentiated hyphae. This compound (trisporic acid) is a carotenoid closely related to retinene. In the saprophyte Achlya, the action of Antheridiol precipitates of the male sexual apparatus (antherids). This molecule is a the formation substituted steroid much like its animal counterparts.