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.     

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.     

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.     

Zur Genese hepatozellulärer Kerneinschlüsse bei Colchicinvergiftung

Summary The colchicin-induced nuclear inclusions are a postmitotic phenomena. Fusing chromosome vesicles often include a portion of cytoplasm, surrounded by persisting parts of the vesicle membranes (indirect or membraned n.i.). This membrane sometimes degenerates; the n.i. then lies free in the karyoplasm (secondarily direct or free n.i.).     

The role of repair in radiobiology

Summary Apart from cancer and mutation induction, radiobiological effects on mammals are mostly attributable to cell death, defined as loss of proliferative capacity. Survival curves relate retention of that capacity to radiation dose, and often manifest a quasi-threshold (shoulder). The shoulder is attributable to an initial mechanism of repair (Q-repair) which is gradually depleted as dose increases. Another form of repair, which is not depleted (P-repair), increases the dose required to deliver an average of one lethal event per cell (dose D₀). Neither form of repair can unambiguously be linked with repair of defects in isolated DNA. An important initial lesion may well be disruption of the complex structural relationship between the DNA, nuclear membrane and associated proteins. One form of P-repair may be restoration of that structural relationship.     

Consideration on the effects of pollution at community and population level

Summary The effects of pollution at population level are considered in relation to demographic characteristics and overall to the birthrate. The direct and indirect effects of pollution on community structure is discussed. The influence of pollution may vary according to the food-chain structure; (as a consequence, the hazard ceteris paribus will be greater in freshwater communities than in marine ones). Relations between diversity and stability are discussed. In addition, the advantages and difficulties in using diversity and biotic indices for monitoring polluted water are taken into account.     

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.     

Nicotianamine,the ‘normalizing factor’ for the auxotroph tomato mutantChloronerva; a representative of a new class of plant effectors

Summary The article surveys our knowledge of the normalizing factor, gained from its discovery a quarter of a century ago up to the present time, under the following headings: Discovery; Physiological properties; Isolation and characterization; Structure determination (Identity of the normalizing factor with nicotianamine); Chemical properties; Analysis; Synthesis; Occurrence and physiological role; Related compounds; Prospects.     

Zum physiologischen Potenzbegriff

Summary Based on the literature and the author's own research on general and comparative heart physiology, the term of Automaty-Potentiality is discussed and differentiated. Adouble term Automaty-Dominance/Automaty-Latence is proposed as serviceable.     

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 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.     

A new functional interpretation of the visual system of male scale insects (Coccida,Homoptera)

Summary In a flight position with vertical body axis, both the dorsolateral and the characteristic ventral lens eyes of male coccid insects are arranged in a horizontal ring around the head. The interpretation that they mainly serve for stabilizing the flight position with regard to the horizon can explain the extraordinary structural features known for these eyes.     

Spierule cells inDrosophila species

Summary Spherule cells are restricted to the larval stage and make up 5–16% of cells in the hemolymph. Their morphology varies between species, mainly due to the shape of their inclusions which may be oval (spheroidocytes), polyhedral (crystalloid cells), or clearly crystalline (crystal cells). These inclusions are very rich in tyrosine. They liquefy rapidly in vitro, whereby the cells become hyaline (coagulocytes).Acknowledgments. We thank Mr B. Barandun for excellent technical assistance. This investigation was supported by the Swiss National Science Foundation, grant No. 3.792.076.     

‘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     

Einfluss des luftelektrischen Feldes auf das Haut-Potential vonRana esculenta

Summary The potential across the skin ofRana esculenta was remarkably reduced under Faraday conditions in comparison to animals kept under normal conditions. A pulsating electric field (10 Hz) practically abolished this effect.     

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.     

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.     

Unterliegt die Heimkehrgeschwindigkeit der Brieftauben hormonalen Einflüssen?

Summary The relation between the homecoming-speed of carrier-pigeons and the influence of sexhormones and prolaktin is reported.It is further examined whether the influence of prolaktin (breeding on 10–15 days old eggs) or psychological factors (feeding of young individuals of more than 15 days) are the factors, accelerating the homecoming-speed. Best results are obtained by combining breeding 1–6 days old eggs and feeding young pigeons of 2–3 weeks.

---

---

In memoriam Heinz Knieriem zu seinem 15. Todestage     

Changes in mouse liver superoxide dismutase activity and lipid peroxidation during embryonic and postpartum development

Summary In inbred mice possessing high and low tissue superoxide dismutase (SOD) activity, it was observed that the difference in the SOD activities of the liver homogenates during development attains the maximum characteristic of the strain by about the 150th day. Subsequently, the SOD activity change displays a tendency in contrast with the age and the basic state. In the course of the development, a difference was also observed between the 2 mouse strains in the lipid peroxidation variation.Part XVIII of the series Properties of enzymes.