Détection cytochimique de l'acide ribonucléique dans les chromosphères pré- et post-méiotiques des sporanges de résistance d'Allomyces

Summary Premeiotic chromospheres in the immature resistant sporangia (RS) ofAllomyces lose their basophily after treatment with trichloracetic acid, perchloric acid or ribonuclease. Postmeiotic chromospheres in the mature RS, becoming the nuclear caps of the ‘reduced’ zoospores, do not stain with toluidine blue or pyronine after ribonuclease digestion. It is concluded that, as gametic and zoosporic nuclear caps, pre- and postmeiotic chromospheres are transitory cytoplasmic organites rich in RNA.      

L'évolution de la symbiose chez les Isoptères

Summary An attempt is made to retrace the evolution of symbiotic associations in Blattopteroidea, with particular reference to Isoptera. It seems probable that double symbiosis occured in the common ancestor of Blattids and Termites: intracellular microorganisms of bacteriocytes, xylophagous intestinal Flagellates. Where as actual Blattids, exceptingCryptocercus, have only retained the former, the primitive Termites, exceptingMastotermes, have only kept the latter. Evolved Termites (fam. Termitidae) have in turn lost the symbiotic Flagellates, but have acquired a rich and complex bacterial flora. — Some of these microorganisms, mixed with their aliments, certainly aid digestion (breakdown of cellulose), whilst others, localised at a particular level of the alimentary canal and not found in the alimentary mass, presumably play a different rôle. Furthermore, Protozoa are constantly associated with certains Termites (xylophagous Amoebae, humus-feeder Ciliates of the genusTermitophrya) and may play some rôle in the process of digestion. Finally, an association occurs between fundgus-growing Termites (subfam. Macrotermitinae) and mushrooms (Termitomyces).     

L'effet de la basse température sur l'incorporation de précurseurs des acides nucléiques et des protéines dans les cellules du méristème radiculaire deVicia faba

Summary The uptake of labelled RNA and protein precursors inVicia faba root meristems into nuclei at 4°C is less depressed than in the cytoplasm. Reversion of the normal pattern of incorporation would seem to indicate an inhibition of the RNA transfer from nucleus to cytoplasm.     

Le développement des ovaires des ouvrières des abeilles et l'ectohormone des reines

Zusammenfassung Die vorliegende Arbeit soll die Begriffe der «Fruchtbarkeitssubstanz» und des «hemmenden Ektohormons» näher bestimmen. Nach unserer Ansicht können aktivierende und hemmende Faktoren einander entgegengesetzte Wirkungen haben. Das Vorhandensein einer Fruchtbarkeitssubstanz bzw. eines trophischen Faktors geht aus unseren Versuchen ebenso wie aus denjenigenMüssbichlers hervor; dies steht aber nicht im Gegensatz zur Wirkung des hemmenden Faktors, der aus dem Tegument der Königin gewonnen werden kann. Auf Filterpapier dargeboten lösen diese Tegumentextrakte ein charakteristisches Verhalten der Arbeitsbienen aus (Antennenbewegungen, Strecken des Rüssels). Die Reizung der Antennen, die mit der oralen Aufnahme des Ektohormons verbunden ist, scheint für die Hemmung der Ovarialentwicklung bei Arbeitsbienen notwendig zu sein.     

Electrophorèse sur gel d'amidon des lipoprotéines sériques humaines

Summary The electrophoretic pattern of human serum lipoproteins after migration in starch gel is different from that obtained by other zone electrophoresis techniques. The most important component which migrates between the slot and slow alpha — 2 globulins may be identified as the component being precipitated by dextrane Sulfate and calcium chloride. The other components have the same mobility as either beta or alpha globulins.     

Etude histochimique de l'action des rayons X sur les cholinestérases

Summary Using a histochemical method, we have observed the cholinesterase activity in mice after X irradiation. Both types of cholinesterases were examined: AChE (specific ChE) of megacaryocytes of spleen and bone marrow, and AChE of motor endplates; and non-specific ChE of liver, pancreas and prostate. There is no inactivation of AChE even after 5000 r. ChE is also very resistant: activity is slowed down only 12 h or even a few days following irradiation and the inactivation remains slight. We suppose that the great alterations in cellular permeability caused by irradiation are not correlated with these enzymes.     

L'électrophorèse sur papier des protéines hydrosolubles du cristallin

Summary By using paper electrophoresis, the authors succeeded in demonstrating different protein fractions in human and animal lenses.Qualitative and quantitative differences were noted in different animals, between the cortical and the nuclear areas of the lens, and also according to age.

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Chargé de Recherches du Fonds national de la Recherche scientifique.     

Sur la présence deβ-alanine dans les tissus des plantes supérieures

Summary -alanine has always been found in peptide hydrolysates of various higher plants, but never in protein hydrolysates. An assumption that the-alanine so found is a constituent of coenzyme A has been suggested.     

Nouvelles considérations sur les moutardes azotées

Summary The cytostatic action of several urethanes-and ureas-nitrogen mustards, as well as that of Endoxan, depends on the appropriate enzymatic activity of the cancerous cell. This enzymatic activity can be considerably stimulated by non-mustard analogues.     

Sur l'origine d'asymétries particulières dans les diagrammes électrophorétiques de solutions de grande viscosité

Summary When electrophoretic studies are made on protein solutions of high viscosity, the beam of light used in the « Schieren » scanning method is partially reflected by the very sharp boundaries which leads to very asymmetric pictures taken by theTiselius-Longsworth method.     

Etude préliminaire des Halos Pléochroïques de quelques Roches métamorphiques et éruptives du St-Gothard

Zusammenfassung Die Untersuchung der pleochroitischen Höfe der Biotite in Orthogneisen, Paragneisen und Bündnerschiefern des südlichen Gotthardmassives ergab durchwegs ein ähnliches Alter, nämlich < 60 Millionen Jahre. Es bedeutet dies, dass eventuell vorhandene vortertiäre Höfe in prätriadischen Biotiten der Gneise während der alpinen Metamorphose fast oder ganz durch Rekristallisation zerstört worden sind.     

Essais d'élaboration des voies d'approche à la chimiothérapie du cancer. Action sur l'eau d'hydratation des tissus néoplasiques; action sur les protéines

Summary The recent successes in chemotherapy suggest that a solution of the same order should now be possible for cancer. The cause of cancer being still unknown, the therapeutic action aimed at is the creation in the organism of conditions unfavorable for cell multiplication. Certain of the factors essential for cell growth, such as the hydrocarbons, have already been studied in this light. The author has demonstrated the possibility of influencing the high degree of hydration of tumor tissue by the use of substances capable of effecting a homogeneous distribution of the dispersed substances in the aqueous phase. Furthermore, it was proposed to influence the protein repair accompanying cell multiplication by means of substances having an affinity for proteins. This was done to effect a condensation of protein elements before they reach the tumor, thus producing a return to the normal concentration of the free protein fraction, and, at the same time, a decrease in the turn-over of these elements through the tumor. Electrophoretic measurements made with theTiselius apparatus have made it possible to follow protein affinity and to suggest the synthesis of compounds containing quinone and imine groups which may prove valuable in future investigations along these lines.     

Action de la triéthylènemélamie sur les mitoses de segmentation de l'œuf de Pleurodèle

Summary Triethylenemelamine (1/400 to 1/12000) induces pseudo-chiasmas and chromosome-breakage in the egg-segmentation mitoses ofPleurodeles waltlii Michah. The primitive effect is stickiness, breakages appear subsequently, but without an interval of time between: the primary physiological and the secondary genetical effect cannot be separated. There are points of breakability, which explains the symmetry of certain fragments. The action is inverted in the epidermal cells of the larvae, where spindle alterations are prominent. Cytodieresis is never inhibited.     

Sur l'influence de l'aneurine sur la formation des nodosités bactériennes nitrogènes

Summary In certain cases, the production of bacterial nodules on legumes can be influenced by aneurin. The preliminary trials should be continued in order to establish the most favourable conditions of aneurin action.     

Essai d'interprétation des résultats obtenus récemment chez les Vertébrés sur l'intersexualité hormonale

Sans résuméLaboratoire de zoologie et d'embryologie expérimentale de la Faculté des sciences de Strasbourg.