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901.
902.
Walter D. Wosilait Carlos Soler-Argilaga Paul Nagy 《Biochemical and biophysical research communications》1976,71(2):419-426
The distribution of palmitate between the form bound by human serum albumin and the free form in plasma was calculated by use of 12 stepwise equilibrium constants and a computer program. Computations were carried out for molar ratios of palmitate to serum albumin of 0.5, 1,2,3, and 4. At most 0.0003% of the palmitate would be in the unbound form, and the remainder distributed among different complexes with albumin. At low molar ratios, the complexes with 1 to 2 moles of palmitate/albumin would predominate while at the highest ratio the complexes of 3 and 4 moles of palmitate/albumin would be most abundant. In the delivery of palmitate to tissues the relative contribution of the different complexes would change, as the molar ratio of fatty acid to albumin changed. 相似文献
903.
James H. Allison Marie E. Blisner William H. Holland Paul P. Hipps William R. Sherman 《Biochemical and biophysical research communications》1976,71(2):664-670
Lithium was found to produce a marked elevation in the levels of -inositol 1-phosphate in the cerebral cortex of treated rats. This effect was completely inhibited by atropine. A 40% reduction in the levels of -inositol 1-phosphate was observed when atropine was given alone. 相似文献
904.
Paul A. Fryxell 《Brittonia》1976,28(3):318-325
Two new species ofBriquetia,B. sonorae andB. inermis, are described from northern Mexico, and another species that ranges from Mexico to Bolivia is transferred into the genus asB. spicata. The genus (previously known as monotypic, Paraguayan-Brazilian) is thereby enlarged from one species to four, and its geographical and morphological limits are greatly expanded. Also, a Mexican species ofAbutilon is transferred toHochreutinera, asH. amplexifolia, enlarging that genus from one to two species. On the basis of this new information, the limits of the informalBriquetia alliance are reconsidered; it is considered to include onlyBriquetia, Dirhamphis, andBatesimalva. 相似文献
905.
Claire-Michelle Calberg-Bacq Camille Francois Luc Gosselin Paul M. Osterrieth Francoise Renteir-Delrue 《生物化学与生物物理学报:生物膜》1976,419(3):458-478
Milk fat globule membranes and mammary tumour virus particles (d = 1.17 g/cm3) have been obtained from the milk of a Swiss albino mice strain. Comparitive biochemistry shows that these two structures differ significantly in the phospholipid, polypeptide and glycopolypeptide patterns and enzymatic activities. However, the lipid profile and the morphology of both structures suggest a filiation with the plasma membrane. Density fractions obtained from the crude virus preparation have been thoroughly investigated. The results suggest that most of these fractions represent degraded virus and/or atypical virus assembly. 相似文献
906.
Paul Mandaron 《Development genes and evolution》1976,179(3):169-183
Résumé Des disques imaginaux de patte, prélevés dans des larves de fin de 3e stade de drosophile, ont été cultivés dans le milieu M de Mandaron, en l'absence d'hormone ou en présence soit d'- soit de -ecdysone. L'incorporation de précurseurs marqués (3H-uridine,3H-leucine ou3H-proline) a été étudiée en fonction du stade de développement des disques.En l'absence d'hormone de mue, l'incorporation d'uridine décroît dès que les disques ont été explantés; l'incorporation de leucine et de proline ne décroît que 6 à 12 heures après l'explantation.- et -ecdysone stimulent l'incorporation des trois précurseurs; toutefois celle-ci varie en fonction du développement morphologique du disque.Les maxima et les minima d'incorporation d'uridine précèdent dans le temps ceux de la leucine et de la proline.Les maxima d'incorporation peuvent être mis en rapport avec des évènements morphologiques marquants du développement: évagination, sécrétion des cuticules nymphale et maginale.Il n'y a pas de différences significatives d'incorporation d'uridine en présence d'-ecdysone ou de -ecdysone; en revanche les maxima d'incorporation de leucine et de proline sont plus élevés en présence d'-ecdysone que de -ecdysone.Ces résultats montrent que l'-ecdysone—et à un degré moindre la -ecdysone—peuvent induire les synthèses de macromolécules nécessaires au développement des appendices in vitro.
Ce travail a été réalisé avec l'aide du CNRS (Action thématique programmée «Différenciation cellulaire», contrat no A 6554324)
Ce mémoire représente une partie de la thèse qui sera soutenue par l'auteur devant l'Université Scientifique et Médicale de Grenoble 相似文献
RNA and protein synthesis inDrosophila leg discs cultured in vitro
Summary Imaginal leg discs from late third instarDrosophila larvae were cultured in Mandaron's medium without hormone or with -ecdysone or -ecdysone. Incorporation of labelled precursors (tritiated uridine, tritiated leucine or tritiated proline) was studied as a function of the stage of in vitro disc development.In the absence of moulting hormone, uridine incorporation decreased as soon as the discs were explanted; leucine and proline incorporation however began to decrease only after 6 to 12 h.- and -ecdysone stimulated the incorporation of all three precursors; however the rate of the incorporation varied as a function of the morphological disc development.The maxima and minima of uridine incorporation preceeded in time those of proline and leucine incorporation.The peaks of incorporation were coincident with salient morphological events of development: evagination, secretion of pupal and imaginal cuticles.There were no significant differences in uridine incorporation in the presence of -ecdysone or -ecdysone. Leucine and proline incorporation maxima however were significantly higher in the presence of -ecdysone than of -ecdysone.The results show that -ecdysone—and to a lesser extent also -ecdysone—can induce the macromolecular syntheses required for the development of the appendage in vitro.
Ce travail a été réalisé avec l'aide du CNRS (Action thématique programmée «Différenciation cellulaire», contrat no A 6554324)
Ce mémoire représente une partie de la thèse qui sera soutenue par l'auteur devant l'Université Scientifique et Médicale de Grenoble 相似文献
907.
Paul Mandaron 《Development genes and evolution》1976,179(3):185-196
Summary Ultrastructural observations were made on imaginal leg discs ofDrosophila cultured in vitro in Mandaron's medium M in the presence of - or -ecdysone.During evagination of discs in vitro the tight epidermal folds of the disc flatten out progressively and the cells change their shape.As the discs evaginate, the pupal cuticle is secreted at the apex of the cells: it comprises a three-layered cuticulin, an epicuticle and a thick endocuticle. Secretion of pupal cuticle always starts by the appearance of dense deposits at the apex of microvilli. Only the latter apparently participate in the construction of the three successive layers of the pupal cuticle.During disc development an abundant rough endoplasmic reticulum is formed. Nuclei and nucleoli become progressively enlarged. At the same time, the nucleus, initially located near the base of the cell, moves closer to the apical cell surface. Microtubules become fragmented as soon as evagination begins and are reorientated parallel to the cell surface (i.e. parallel to the new long axis of the cell) at the end of evagination.
Ce travail a été réalisé avec l'aide du CNRS (Action thématique programmée) «Différenciation cellulaire», contrat no A 6554324.
Ce mémoire représente une partie de la thèse qui sera soutenue par l'auteur devant l'Université Scientifique et Médicale de Grenoble. 相似文献
Ce travail a été réalisé avec l'aide du CNRS (Action thématique programmée) «Différenciation cellulaire», contrat no A 6554324.
Ce mémoire représente une partie de la thèse qui sera soutenue par l'auteur devant l'Université Scientifique et Médicale de Grenoble. 相似文献
908.
909.
Antiserum against PGE2 was raised in rabbits following immunization with prostaglandin-hen-γ-globulin conjugate. The antiserum exhibited 14% cross reactivity with PGE1 and far less cross-reaction with heterologous prostaglandins. A microcolumn of Sephadex LH-20 was used for a partial, but sufficient separation of PGE2 from PGE1 and a complete separation from heterologous prostaglandins to ensure a specific RIA for PGE2. The precision of the method in the range 10–500 picograms showed a coefficient of variation varying between 4 and 13%. The detection limit was 10 picograms corresponding to 15 pg/ml of PGE2 in serum.In order to demonstrate the validity of the method values obtained for non-diuretic rat renal venous serum were compared with those obtained using the isotope derivative method of Bojesen & Buckhave (1972) on the same samples. The concentrations of PGE2 obtained were 239 ± 25 pg/ml and 250 ± 58 pg/ml, respectively. 相似文献
910.
Janice L. White Marvin L. Hackert Manfred Buehner Margaret J. Adams Geoffrey C. Ford Paul J. Lentz Ira E. Smiley Steven J. Steindel Michael G. Rossmann 《Journal of molecular biology》1976,102(4):759-779
Details are recorded of the X-ray diffraction data collection, heavy atom refinement and preliminary structure refinement for two different dogfish M4 lactate dehydrogenase structures. One of these is the 2.0 Å resolution apoenzyme structure; the other is a 3.0 Å resolution abortive ternary complex. Two other ternary substrate inhibitory complexes (LDHase2: NAD: oxalate and LDHase: NADH: oxamate), isomorphous with the abortive ternary complex (LDHase: NAD-pyruvate), have also been examined. The apo-LDHase and LDHase: NAD-pyruvate structures are systematically compared to determine significant differences in their conformation. These are related to differences in structure amongst the three studied ternary complexes. These differences all occur in regions of the protein around the active site, particularly the flexible loop covering the active center pocket and the C-terminal helix αH. The changes are suggestive of a domino effect whereby the closing of the loop on binding coenzyme and substrate triggers the critical reactive residues into assuming their catalytically active positions. 相似文献