Über die Konstitution der Visnagane und Khellactone ausAmmi visnaga L.

Summary The visnagans fromAmmi visnaga L. and the stereoisomeric khellactones and methyl-khellactones derived from them were transformed into seselin and umbelli-ferone-8-aldehyde. These transformations and other degradations lead to revised formulas for these natural compounds.     

Über Inhaltsstoffe ausPetasites officinalis Moench I. Petasin und die Petasolester B und C

Summary Three spasmolytically active substances which contain no nitrogen, namely petasin and the petasolesters B and C, were isolated fromPetasites officinalis Moench. They are all esters of the same C₁₅-alcohol. Petasin is an ester of angelic acid, whereas the petasolesters B and C are derivates of a new acid containing sulphur, the-methylmercapto-acrylic acid.     

Genetische und biochemische Untersuchungen über die Bedeutung der Amino- und Nucleinsäuren im Ursachengefüge von Neoplasmen (Tumoren und Gallen). Ein Dauermodifikationsbzw. Prädeterminationsphänomen

Summary If certain hybrids ofPlatypoecilus maculatus andXiphophorus helleri (viviparous platyfish and swordtails) are cultivated in diluted sea-water (0.25 or 0.5% salt concentration), the amount of free amino acids increases and the growth of macromelanophores, which normally only form certain black spots at the dorsal fin, is accelerated. Therefore melanomas arise. After changing salt water for fresh water, growth of macromelanophores remains accelerated. The same effect is seen in progenies which have been in an oocytic or embryonic state, when their mother was cultivated for some weeks in diluted sea-water (Figures 1 and 2). A similar effect has been observed in plant galls produced byPhylloxera (Viteus vitifolii) in the genusVitis. When the parasite, which injects amino acids into the tissue of the host in order to produce galls, is removed, gall formation goes on slowly for some days. It is shown that a few hours after injection of amino acids—before formation of neoplasms begins—the concentration of ribonucleic acids is increased. RNS-(and therefore protein-)biosynthesis in neoplasms may be dependent on concentration of free amino acids. A simple concept for the formation of neoplasms in hybrids of platyfish and galls ofPhylloxera is discussed.

---

---

Den Herren Prof. Dr.G. de Lattin (Zoologisches Institut der Universität des Saarlandes) und Prof. Dr.B. Husfeld (Forschungsinstitut für Rebenzüchtung Geilweilerhof/Pfalz) sind wir für die Förderung dieser Arbeit zu grösstem Dank verpflichtet. Herrn Prof. Dr.C. Kosswig (Zoologisches Institut der Universität Hamburg) verdanken wir viele Anregungen und die freundliche Überlassung von ingezüchteten Stämmen für unsere Fischkreuzungen. — Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Untersuchungen über den Ascorbigengehalt von Kohlrabi(Brassica oleracea v.gongylodes) während der Vegetation und den Zusammenhang zwischen Ascorbigen und Wachstum bei den Pflanzen der Familie Brassicacae

Summary The distribution of ascorbigen in various organs of kohlrabi during vegetation suggests that ascorbigen probably plays a part in the metabolism of the indole growth-substances of numerous Brassicacae.     

Untersuchungen über Bildung und Weitergabe von Drüsensekreten beiFormica (Hymenopt. Formicidae) mit Hilfe der Radioisotopenmethode

Summary Marking experiments with the tracer isotope P³² had the result that food-secretion of ants is mainly formed in the pharyngeal gland, then reaches the crop through the exit channel of the gland, where it is stored and released again, on regurgitation-stimuli, to and and larvae as well as workers.     

Über eine bakterielle Vorverdauung und eine proteolytische Hauptverdauung im Darm der Nashornkäferlarve (Oryctes nas. L.)

Summary The larva ofOryctes nas. L. shows a bacterial predigestion in the rectal-saccus. The main breakdown of proteins takes place in the middle gut, closely connected with the act of regurgitation.