Comptes rendus des seances de l'Academie des sciences. Serie III, Sciences de la vie最新文献

A structural model of the bovine rhodopsin in the discal membrane is proposed, based on the data obtained from the proteolytic and BNPS skatole fragments of the protein. The striking features of the model are the presence of seven transmembrane segments and of a large extradiscal peptidic loop and the localisation of the retinal site.

The ultrastructural study with morphometric research was realized on beta granules of B cells of pancreatic islets of the normoglycemic Sand Rat, Psammomys obesus, in its biotope. The physiological signification of cytologic and morphometric findings of beta granules is discussed.

We studied in pregnant Rat the effect of 1,25-dihydroxycholecalciferol (1,25(OH)2D3) alone or associated with calcitonin on fetal bone resorption measured by organ culture. 1,25(OH)2D3 (0.1 microgram per day) reduced fetal weight and increased fetal bone resorption. Calcitonin (30 mU/hr.) alone had no significant effects but, associated with 1,25(OH)2D3, it protected mother and foetus against the effect of the vitamin D3 metabolite.

A dialysable and thermostable compound was partially purified from Cnestis glabra (Connaracea) seeds. It is insoluble in organic solvents. At a dose corresponding to 0.5 g of seeds it has a lethal effect on mice after convulsive attacks. Sodium dipropylacetate, an anticonvulsive agent prevents the convulsions but not the death of the animals. The toxic compound inhibits protein synthesis in a rabbit reticulocyte lysate and in hepatoma tissue culture; moreover in the cell culture, the incorporation of thymidine into DNA is inhibited.

An increased frequency of high titers of antibodies against A, B, ORh+ trypsinized, and ORh+ neuraminidase-treated human red blood cells was observed in the sera of Africans living in a malaria endemic area, and Europeans with primary malaria attacks. In the latter group, titers of agglutinins against neuraminidase treated RBC were increased in 84% of individuals and were of the IgM class. Inhibition experiments with beta-D-galactose and lactose showed that this agglutinin was directed to the T antigen of human RBC. Its possible implication in malaria related anemia is discussed.

The present paper deals with the particular behavior of the complexes formed between pancreatic elastase and seric inhibitors in the Pig, when they were set in contact with homologous elastin. The previously known values of dissociation constants of alpha 1-antiprotease-elastase and alpha 2-macroglobulin-elastase complexes indicated they were very stable and almost irreversible. Nevertheless, our results suggest that, when the overall complexes between porcine pancreatic elastase and seric inhibitors were isolated in non drastic conditions, they might develop an elastolytic activity against elastin fibers. This result is important as regards atherosclerosis--in Human--where a destruction of elastin is involved at a early stage of the disease.

Among the three strains of Clostridium acetobutylicum we investigated: NRRL 592, NCIB 619 and ATCC 824, only the last was shown to contain a NADH: rubredoxin oxidoreductase activity. We report that the biosynthesis rate of this enzyme fluctuated in the proportions of 1 to 50 according to the growth phase and medium composition. These variations reflect a mode of regulation adjusted to the metabolism of bacteria.

Citrulline production is demonstrated in murine bone marrow cell cultures incubated with dialyzed secondary MLC supernatant. This synthesis, proceeding from arginine, is induced by a soluble protein factor released during secondary MLC, unstable to heat, with a molecular weight of approximately 150,000 daltons.

6 new OLA factors of the Sheep histocompatibility complex are described. 3 of them, C 14, C 15, C 17 are the products of 3 alleles at a third locus of the complex: OLA-C, closely linked to OLA-A and B. Two factors A 13 and B 12 are the products of 2 alleles at OLA-A and B loci. The last factor (16) is the product of an OLA gene, the locus of which is not yet defined. 28 haplotypes are described. Genes at the 3 OLA loci are in linkage disequilibrium.