Découverte de microfaunes de l'Albienmoyen et supérieur dans la vallée de Joux (Jura Vaudois,Suisse)

The discovery of Foraminifera and Ostracodesin the dark green, sandy-glauconitic marl clay in the Joux Valley (in the Vaudois Jura) suggests to date these sediments Middle and Upper Albian. The Ostracode associations are similar to those found in the Paris Basin, but different from those which characterize the subalpine region.     

Mapping of the structural gene for the second component of complement with respect to the human major histocompatibility complex.

Families have been HLA typed, and allotypes of the second component of complement and properdin factor B determined. The lod score for the C2 structural gene and HLA-B from the study of 11 families and 55 informative meioses was 14.39 at maximum likelihood estimate of the recombination fraction of .02. This is related to other estimates of the distance between these two genes. The relative kinetic activities of the C2 allotypes were studied and no differences were demonstrated. No crossovers between Bf and C2 were observed.     

Genetic polymorphism of serum complement components in the chimpanzee

Significant polymorphism of serum complement components Bf, C2, C3, C6, and C8 in the chimpanzee has been demonstrated. The data are consistent with the hypothesis thatC2 andBf are closely linked toChLA and argue against close linkage ofChLA toC3 or toC8, as in man. In addition, a blank allele for C6 and C6 deficiency was detected in several chimps.     

Microcalorimetric evaluation of the efficacy of the alkaline treatment on the fermentation of straw

Summary A microcalorimetric study is proposed to follow the degradation of straw by a mixed bacterial culture. The effect of an alkali pretreatment of straw is described.     

Double helical arrangement of spread dinoflagellate chromosomes

Dinoflagellate chromosomes observed in thin section show regular patterns which have been shown to correspond to a liquid crystalline helicoidal arrangement of DNA. Peripheral DNA filaments form a system of loops in the surrounding nucleoplasm. When such chromosomes (studied in Prorocentrum micans) are in presence of water, they extend considerably and form a double helical bundle. At the periphery of these bundles, one observes numerous filaments, which are smooth and devoid of nucleosomes; their diameter is constant.This study, in phase contrast and in electron microscopy, allows statistical measurements. A geometrical model is proposed and shows the simplest way to pass from the intact to the extended form. The liquid crystalline character of the chromosome is probably involved in the extension mechanisms.     

Interaction of melittin with dimyristoyl phosphatidylcholine liposomes. Evidence for boundary lipid by raman spectroscopy

The interaction of melittin, a polypeptide consisting of 26 amino acid residues, with dimyristoyl phosphatidylcholine bilayers was investigated by vibrational Raman spectroscopy. Spectral peak height intensity ratios, involving vibrational transitions in both the 3000 cm^?1 acyl chain methylene carbon-hydrogen stretching mode region and the 1100 cm^?1 acyl chain carbon-carbon skeletal stretching mode interval, served as temperature profile indices for monitoring the bilayer order-disorder processes. For a lipid : melittin molar ratio of 14 : 1 two order-disorder transitions were observed. In comparison to a gel to liquid crystalline phase transition of 22.5°C for the pure lipid, the lower transition, exhibiting a 2°C width, is centered at 17°C and is associated with a depression of the main lipid phase transition of dimyristoyl phosphatidylcholine. The second thermal transition, displaying a 7°C interval, occurs at approx. 29°C and is associated with the melting behavior of approximately seven immobilized boundary lipids which surround the inserted hydrophobic segment of the polypeptide. For a lipid : melittin molar ratio of 10 : 1 two thermal transitions are also observed at 11 and 30°C. As before, they represent, respectively, the main gel to liquid crystalline phase transition and the melting behavior of approximately four boundary lipids attached to melittin. From these data alternative schemes are suggested for disposing the immobilized lipids around the hydrophobic portion of the polypeptide within the bilayer.     

Préparation de cellules isolées de mesophylle deValerianella olitoria Poll,et étude de leur aptitude à l’absorption du 3-O-méthyl-D-glucose

This paper describes a procedure for isolation and preservation of mesophyll cells, adapted toValerianella olitoria. We have tested the best conditions of temperature, pH, enzyme concentration, plasmolysis and the action of several adjuvants, dithioerythritol and mineral nutrients. The method described gives a high yield of viable cells. The ability of isolated cells and cellsin situ to take up methyl-glucose is compared.

---

     

Occurrence of subcutaneous zygomycosis (Entomophthoromycosis Basidiobolae) caused by Basidiobolus haptosporus with pulmonary involvement

A case of a two-year-old boy with multiple subcutaneous lesions caused by Basidiobolus haptosporus is presented.The child had also a non-toxic familial goiter and clinical and radiological features of a pulmonary illness. The pulmonary manifestations only disappeared with the treatment with potassium iodide. The authors think that the pulmonary lesions must have arisen by direct spread of the fungus from the subcutaneous lesions of the chest.     

Effects of four agents that modify microtubules and microfilaments (vinblastine,colchicine, lidocaine,and cytochalasin B) on macrophage-mediated cytotoxicity to tumor cells

Summary The effects of vinblastine, colchicine, lidocaine, and cytochalasin B on tumor cell killing by BCG-activated macrophages were examined. These four drugs were selected for their action on membrane-associated cytoskeletal components, microtubules, and microfilaments. Colchicine and vinblastine, which block microtubular synthesis, inhibit macrophage-mediated tumor-cell cytotoxicity at a concentration of 10^–6 M. Cytochalasin B, which disrupts microfilaments, enhances tumor cell lysis and stasis due to activated macrophages at a concentration of 10^–7 M. Lidocaine, which may induce the disappearance of both microtubules and microfilaments, has the same inhibiting effect as vinblastine at a concentration of 5×10^–7 M. Whereas vinblastine and lidocaine seem to act on the macrophage itself, cytochalasin B exerts its effect predominantly on the tumor cell. These results suggest that microtubules and microfilaments play a role in the destruction of tumor cells by activated macrophages.