On the origin of the protein yolk in the oocytes ofAplysia depilans (Gastropoda,Opistobranchia)

Summary In the oocytes ofAplysia depilans it has been observed electronmicroscopically that gemmae or daughter-nucleoli separate from the nucleolus. These gemmae after having overcome the nuclear membrane, would aggregate together, even after transformation, into yolk globules. These observations seem to give plausibility to the hypothesis that there is a close relationship between production of ribonucleoproteic material by the nucleolus and yolk production.     

Further morphological and biochemical studies on normal and hybrid embryos of sea urchins

Zusammenfassung (1) Es wurde bei den SeeigelartenParacentrotus ,Arbacia undSphaerechinus sowie den drei BastardenPar ×Arb ,Arb ×Par undPar ×Sphaer für eine Reihe von Entwicklungsstadien die Anzahl der Kerne pro Keim bestimmt (Tabelle). Der morphogenetischen Hemmung der Bastarde entsprechen herabgesetzte Kernzahlen und parallel eine Herabsetzung der DNS-Synthese. (2) Es wurde bei den genannten reinen Arten und den Bastarden derUmsatz der RNS bestimmt. Er geht in allen Fällen, bei den reinen Arten wie bei den Bastarden, der DNS- Synthese parallel.

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Our work was supported by a grant from the Schweizerischer Nationalfonds zur Förderung der wissenschaftlichen Forschung. We express our sincere thanks to the Nationalfonds and also to the authorities at the Zoological Station at Naples for generous help and supply of materials and facilities. — This paper is thankfully dedicated byF. Baltzer toF. E. Lehmann for his kind hospitality in the Bernese Institute.     

Changes in the lumen of coronary vessels under oligemic hypotension

Conclusions The decrease of circulating blood volume, resulting in oligemic hypotension, may evoke in anaesthetized cat the active constrictory coronary vessel responses of 2 types, one occuring immediately after start of the hypotension and the other having a significantly prolonged latency.

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Structural differences of cone ‘oil-droplets’ in the light and dark adapted retina ofPoecilia reticulata P.

Summary The vast majority of oil-droplets in the dark and light-adapted retinal twin-cones ofPoecilia reticulata is of the matrix-type. In bright light (day light+overhead strip light) there occurs in some regions a very pronounced numerical change from matrix to cristate-type, whereas other regions remain unaffected. The functional significance of these differences is discussed.     

Nature and the time course of the effect of CO2 on electroretinogram (ERG) in an arachnid

Summary Electroretinogram recorded from the median eye of the scorpion, Heterometrus fulvipes before and after exposure to CO₂ indicated that the rate of recovery of b wave to pre-CO₂ level was slow and delayed as compared to a wave. b wave may therefore have a more central origin than that of a wave, which finds corroboration in the results of the depth recording in this eye with the microelectrode.The equipment was a gift from USAFOSR to Prof. T. H. Bullock and Prof. K. P. Rao, and the work was carried out at the Department of Zoology, Bangalore University. I thank Dr R. V. Krishnamoorthy and Dr A. R. Kasturi Bai.     

On the host-symbiont-cycle of a leafhopper (Euscelis plebejus) endosymbiosis

Summary In the host-symbiont-cycle ofEuscelis plebejus and its bacterial symbionts each of both symbionts (a and t) appears in an infection form during the intraovarial transmission (adult female) as well as during the entrance into the mycetocytes (embryo) and in a vegetative form during the remaining time of the cycle.This work was supported in part by a grant from the Deutsche Forschungsgemeinschaft to ProfessorK. Sander, whom I thank for helpful discussions.     

Independent responses of two fruit characters to developmental regulation inMicroseris douglasii (Asteraceae,Lactuceae)

Summary The hairy achenes and yellow achenes characters are expressed only in peripheral fruits onMicroseris capitula. Segregation in interstrain hybrid D37 shows that the genes responsible for these characters respond independently to developmental regulation.Supported by grants Ba 536/7-7 from the Deutsche Forschungsgemeinschaft, and DEB 80-09427 from the National Science Foundation.     

Limitations of the ‘direct linear plot’ in evaluation of drug-protein binding parameters

Summary The applicability of the direct linear plot is compared with that of the Scatchard plot for the estimation of protein binding parameters. Only, if one class of binding sites exists in the system tested, binding parameters may be estimated by use of the direct linear plot. On the other hand the Scatchard plot also provides estimates in systems with more that one class of binding sites.     

‘Action substances’ of peripheral nerve re-visited

Fifty years ago, four action substances were described as being liberated from peripheral nerve in the course of activity. An attempt has been made to update this information. Confirmatory evidence is available that acetylcholine and thiamine do play a role in the course of activity. However, the question of the relationship in time between their release and the electrical events, and the possible effect on specific ionic gating mechanisms, remains unclarified. The liberation of potassium has been found to be a transmembrane K efflux, and the question of the existence of another substance similar to thiamine has not been pursued.a member of the Editorial Board of EXPERIENTIA from 1974 to 1982     

Furocaulerpin,a new acetylenic sesquiterpenoid from the green algaCaulerpa prolifera

Summary Furocaulerpin, an acetylenic sesquiterpenoid possessing a furan ring, has been isolated from the marine algaCaulerpa prolifera, and its stereostructure elucidated mainly on the basis of physico-chemical data.This work was carried out in the frame work of the Progetto Finalizzato per l'Oceanografia e i Fondi Marini, CNR, Rome. Thanks are due to the Centro di Metodologie Chimico-Fisiche of the University of Naples (Mr I. Giudicianni) for the determination of PMR-spectra.     

Axillary 5α-androst-16-en-3-one in men and women: Relationships with olfactory acuity to odorous 16-androstenes

Summary Axillary 5-androst-16-en-3-one (5-androstenone) levels were found to be significantly higher in men than in women but do not vary between left and right axillae, are not related to age, handedness or degree of hirsutism (in women) nor to anosmia to this steroid. In men (but not in women), levels are related linearly to axillary cholesterol concentrations but not to squalene. Olfactory thresholds for 5-androstenone varied widely, the lowest recorded being 0.2 ppb, but there was no difference in thresholds between men and women. Women (70%) found the smell repellant but anosmia did not differ greatly between men and women (9–20%). Anosmia to the smell of 5-androst-16-en-3-ol was most marked in women (90%) rather than in men (45%). Axillary 5-androstenone values were generally consistent with the musky or strong smells of male axillary extracts, compared with the sweet smell of those from female subjects.Supported by the Herbert Dunhill Trust.     

Chromosomal location of α-amylase structural genes in rye (Secale cereale L.)

Summary Rye (Secale cereale L.) -amylase isozymes are controlled by at least four loci located on the 5R (three) and 7R (one) chromosomes. In the case of Imperial and King II cultivars, two of the three 5R chromosome loci could be specifically located on the 5Rl chromosome arm; the other one was located on the 5RS. The locus of 7R chromosome was located on the 7RL chromosome arm of Imperial rye.     

Induction of ingestive responses by cAMP applied into the rat hypothalamus

Riassunto L'applicazione stereotassica di microdosi di dibutirril-adenosin-3 5 monofosfato nell'area ipotalamica laterale zona incerta di ratti sazi causa un netto aumento nell'ingestione di acqua. L'aumento è molto simile a quello causato dalla carbamoilcolina posta nella stessa zona.     

Paul Ehrenfest on the Necessity of Quanta (1911): Discontinuity,Quantization, Corpuscularity,and Adiabatic Invariance

Our object in this paper is to study the antecedents, contents, implications, and impact of a not well-known or appreciated paper by EHRENFEST in 1911 on the essential nature of the different quantum hypotheses in radiation theory. After a careful analysis of EHRENFESTs notebooks, correspondence, and publications, we conclude that the essential points of EHRENFESTs paper were not perceived to a large extent, and hence that its implications were not considered thoroughly. Specifically, we show that EHRENFEST contributed significantly to the clarifications of the differences between PLANCKs and EINSTEINs respective quantum hypotheses, as well as to those of the concepts discontinuity, quantization, and corpuscularity.     

Conjugated terpenoid ketones: A new group of plant growth regulators

Summary ,-unsaturated terpenoid ketones have a root-inducing property on the hypocotyl cuttings ofPhaseoulus aureus. Significantly isopathcoulenone, (I) is distinctly more active in causeing rooting over IAA.Acknowledgment. The work was financially supported by the Punjab State Government, India, under the scheme Chemistry of some natural products and their significance in agriculture. The authors thank Dragoco, Holzminden, Federal Republic of Germany, for supplying the samples of monoterpenes.     

Single amino acid substitutions insn-glycerol-3-phosphate dehydrogenase allozymes fromDrosophila virilis

Summary The amino acid sequence was compared among the three allelic variants (allozymes) ofsn-glycerol-3-phosphate dehydrogenase inD. virilis, which are detected by one-dimensional electrophoresis. The GPDH^f variant was different from the GPDH^m by only one substitution of 68-lysine for asparagine; GPDH^s differed from GPDH^m by substitution of 127-glycine for arginine. No electrophoretically silent substitutions were found in a total of 352 amino acid residues.     

Frescon: Neurophysiological action of a molluscicide

Summary The molluscicide N-trityl morpholine (Frescon) has an unusual effect on the central nervous system of a freshwater snail. Nerve impulses become grouped into spontaneous bursts, with many cells firing synchronously. This may result from interference with inhibitory processes.We thank Dr.C. B. C. Boyce of Shell Research for materials and information.     

Suppression of delayed type hypersensitivity of mice by lead

Summary Application of lead suppressed the delayed type hypersensitivity (DTH) of mice induced by sheep red blood cells (SRBC). Inhibition of elicitation of DTH in primary as well as in secondary response was correlated with the concentration of lead in the blood of the mice.Acknowledgments. Supported by the Georg-und-Agnes-Blumenthal-Stiftung and the Verein für Wasser-, Boden- und Lufthygiene. We thank Miss Schachtschneider for the excellent technical assistance.