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.     

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.     

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.     

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.     

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.     

Real-time models of morphogenetic processes

Summary Morphological transformations are often describable by simple series kinetic models,AB, ABC, etc., which allow assessment of the rates of interconversion of the distinguishable shapes or forms present and their probabilities of occurrence at various points in time, thus providing a means for kinetic comparisons with biochemical measurements of the molecular-level reactions that cause the transformations. When changes in cell morphology are followed turbidimetrically, the real-time progress curves can be simulated by fitting the data to a form of Beer's law for scattering by mixtures in which the species concentrations change with time in accordance with the chosen kinetic scheme. Because many even relatively large cells are mostly water, classical light scattering theory can be used to interpret the turbidimetric data in terms of simple geometrical models ofaverage cell size and shape suggested by microscopic examination. Two examples are briefly considered, the stimulus-induced changes in blood platelet shape and apparent size and their correlation with cytosolic-free calcium, and apparent swimming motion exhibited by neutrophils in suspension.What do you know about this business? the King said to Alice. Nothing, said Alice. Nothing whatever? persisted the King. Nothing whatever, said Alice. That's very important, the King said. Lewis Carroll (1865), in Alice's Adventures in Wonderland     

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.).     

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.     

Über die PAS-Glykogen-Reaktion im Bereich der Ringbinden beiAmblystoma mexicanum Cope

Summary Glycogen substance, detected by the PAS-reaction in the so-called Ringbinden of the trunk musculature from the larval form ofAmblystoma mexicanum Cope, is described. The PAS-glycogen reaction in the myofibril complex of the common Ringbinde does not differ from that found in the normal one.     

Influence du rang de ponte dans la transmission du caractèreatrophie gonadique chezDrosophila melanogaster

Summary Gonadal atrophy (atrophie gonadique, ag) is a hereditary character of variable expression and penetrance inDrosophila melanogaster, the penetrance of which varies with temperature but also with the rank order of eggs produced. It is shown that early zygotes are more often affected than late zygotes who not only, but also transmit the character more efficiently to their offspring.     

Etude de l'hydrolyse et des propriétés toxiques vis-à-vis des mitochondries de maïs Texas,d'un insecticide,le méthomyl ou S-méthyl-N [(méthylcarbamoy)oxyl] thioacétimidate

Summary Methomyl, or S-methyl-N [(methylcarbamoyl)oxy] thioacetimidate, a common insecticide, has been found to be a specific poison of mitochondria of corn with Texas cytoplasm. Its hydrolysis under very mild acidic conditions affords thiomethyl methylthiosulphonate, which strongly inhibits the activity of CmST and N mitochondria of corn.     

Biochemical evidence for two types of noradrenaline storage particles in rabbit iris

Summary Centrifugation techniques were used to determine the subcellular distribution of noradrenaline (NA) and dopamine -hydroxylase (DH) in the rabbit iris. By application of isopycnic and differential gradient centrifugation methods 2 types of NA vesicles could be demonstrated. Of the total particle bound NA about 70% is associated with light and about 30% with heavy vesicles. For both types of vesicles the distribution of DH reflected that of NA.     

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.     

A mathematical approach to cognitive processes

Summary A mathematical formalization of cognitive processes based on concepts previously given in Experientia¹ is presented. Cognitive processes are described as a set of exponentially decaying interaction probabilities determined by previous interactions between different elements and an association parameter, the inverse of the cognitive stability. The interactions occur in a cognitive string surrounded by a cognitive plasma which carries the contextual information. The complexity of a cognitive process is proportional to time.     

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.     

Der Einfluss sogenannter Ovulationshemmer auf die Esteraseaktivität des Endometriums

Summary Histochemical investigations were carried out in the endometrium of guinea-pigs after administration of Anovlar (4 mg ethinylnortestosterone-acetate and 0.05 mg ethynylestradiol). Histochemically a decrease of non-specific esterase activity was found in the endometrial as well as in the glandular epithelium after Anovlar treatment. The relationship of this enzyme to synthetic steroid hormones is briefly discussed.     

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.     

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.     

Glycoprotein biosynthesis in splenic cells. Purification of a microsomal galactosyl-transferase

Summary One part of the microsomal galactosyl-transferase activity of splenic cells of rats can by solubilized by the action of Triton X-100 and Tween 20. Its purification on a Sephadex G-200 column and by electrophoresis on a polyacrylamide gel leads to a solution of high specific enzymic activity.This work has benefited from the help of the Centre National de la Recherche Scientifique, the Direction des Recherches et Moyens d'Essais, the Institut National de la Santé et de la Recherche Médicale, the Fondation pour la Recherche Médicale Française the Délégation Générale à la Recherche Scientifique et Technique and the Université de Lyon (UER Lyon-Sud et Biologie Humaine).