The carbon-13 nuclear magnetic resonance spectra of four eudesmane sesquiterpenols

The ¹³C NMR spectra of geosmin, selina-4(14),7(11)-diene-99-ol and two dihydroeudesmol isomers have been obtained and the individual resonances assigned. Several different empirical correlations developed by others have been combined in simple calculations to predict chemical shift values for sesquiterpenols of the eudesmane group.     

Ecdysteroids regulate the release and action of eclosion hormone in the tobacco hornworm, Manduca sexta (L.)

The relationship between the ecdysteroid titre and eclosion hormone was explored for the pupal and adult ecdyses of Manduca sexta. Ecdysteroid treatment late during either moult caused a dosedependant delay in the time of ecdysis. Sensitivity to exogenous steroid treatment dropped off as the respective moults neared completion and in both cases coincided with the time of the low point in the endogenous ecdysteroid titre. It was concluded that an ecdysteroid decline is a normal prerequisite for the ecdyses of both stages. The steroid drop is important for two aspects of the eclosion hormone system: it causes target tissues to become sensitive to the peptide and it is a prerequisite for the subsequent release of eclosion hormone itself. Thus, the dual action of the declining ecdysteroid titre insures that when eclosion hormone is released, the tissues will be competent to respond to it.     

Substitution of Milk for Serum in the Production of Human Leukocyte Interferon

The presence of serum in suspensions of Sendai-induced human leukocytes is necessary for the synthesis of significant amounts of interferon. Very little interferon is obtained from serum-free suspensions. Cow's milk or milk casein can substitute for serum in the production of high yields of human leukocyte interferon.     

THE HUMAN CHROMOSOME : Electron Microscopic Observations on Chromatin Fiber Organization

Human lymphocytes were grown in short-term tissue culture and were arrested in metaphase with Colcemid. Their chromosomes were prepared by the Langmuir trough-critical point drying technique and were examined under the electron microscope. In addition, some chromosomes were digested with trypsin, Pronase, or DNase. The chromosomes consist entirely of tightly packed, 240 ± 50-A chromatin fibers. Trypsin and Pronase treatments induce relaxation of fiber packing and reveal certain underlying fiber arrangements. Furthermore, trypsin treatment demonstrates that the chromatin fiber has a 25–50 A trypsin-resistant core surrounded by a trypsin-sensitive sheath. DNase digestion suggests that this core contains DNA.     

Simple Medium for Pigment Production by the Erythrasma Diphtheroid

A simple method for the isolation and identification of the causative diphtheroid of erythrasma, Corynebacterium minutissimum, utilizes Muiller-Hinton Agar.     

The incidence of double-yolked eggs in relation to improvement in egg production

Summary The production of double-yolked eggs and its relation to other egg production traits has been summarized over a period of thirty years for a closed flock selected for gains in total egg production.The number of double-yolked eggs per pullet as well as the percentage of pullets laying at least one double-yolked egg have increased rather steadily, although it is evident that the trait possesses no selective advantage. Pullets which laid double-yolked eggs showed earlier sexual maturity and superiority in egg production but it is clear that the corresponding genetic correlations are low or negligible.The heritability of the trait increased with its level of incidence and is sufficiently high that selection should increase the incidence to a level permitting further study of multiple ovulation.

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Zusammenfassung An einer für eine Steigerung der Ei-Produktion ausgewählten Herde Weißer Leghornhühner wurde der Anfall von Eiern mit zwei Dottern und ihre Beziehung zu anderen Merkmalen der Ei-Produktion für einen Zeitraum von 30 Jahren zusammengestellt.Die Anzahl doppeldottriger Eier je Hühnchen und der Prozentsatz Hühnchen, die wenigstens ein doppeldottriges Ei legten, ist ziemlich konstant geblieben, wenn auch dieses Merkmal offensichtlich keinen Selektionswert hat. Hühnchen, die Eier mit zwei Dottern legten, zeigten eine frühere Geschlechtsreife und eine höhere Ei-Produktion, aber es ist klar, daß die entsprechenden genetischen Korrelationen niedrig sind.Die Erblichkeit des Merkmals stieg mit seinem Auftreten, sie ist hoch genug, daß eine Selektion das Auftreten noch steigern könnte, um eine weitere Untersuchung der mehrfachen Ovulation zu ermöglichen.

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Dedicated to Professor Hans Stubbe on the occasion of his 65^th birthday.