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991.
Physical map of two D. melanogaster DNA segments containing sequences coding for the 70,000 dalton heat shock protein. 总被引:22,自引:0,他引:22
L Moran M E Mirault A Tissières J Lis P Schedl S Artavanis-Tsakonas W J Gehring 《Cell》1979,17(1):1-8
The isolation of the two hybrid plasmids 56H8 and 132E3, which contain D. melanogaster (Dm) DNA sequences complementary to the mRNA coding for the 70,000 dalton heat shock protein, has been reported (Schedl et al., 1978). Here we compare the sequence arrangement in the two cloned Dm DNA segments by restriction, cross-hybridization and heteroduplex analysis. The results show that the two cloned DNA segments derive from nonoverlapping regions of the Dm genome; that they contain homologous regions present once in 56H8 and twice in 132E3; and that each homologous region is composed of three distinct contiguous sequence elements, x, y and z, which together define a 3 kb common unit. While the 2.5 kb z elements show a high degree of sequence homology in all three common units, the three x and y elements display an intriguing relationship. The localization of the mRNA coding sequences within each of these common units is presented in the accompanying paper (Artavanis-Tsakonas et al., 1979). 相似文献
992.
This report that (1) cells mediating NK activity in different inbred mouse strains selectively express one of two allelic products specified by theLy-5 locus (or a locus tightly linked to it) and (2) this surface structure may directly contribute to NK-mediated cytolysis, since Ly 5 antiserum specifically inhibits NK activity in vitro in the absence of complement. 相似文献
993.
Denise Mouton Anne -Marie Heumann Yolande Bouthillier Jean Claude Mevel Guido Biozzi 《Immunogenetics》1979,8(1):475-486
The antibody response to a threshold dose (10) of SE was studied in the High responder line (H) and the Low responder line (L) of mice obtained by bidirectional selective breeding for the character quantitative agglutinin response to an optimal dose of SE, and in interline hybrids: F1, F1 and both backcrosses. Whereas the interline difference in agglutinin responses at the optimal dose is due to the additive effect of about ten independently segregating loci, one of which isH-2 linked, the responsiveness to the threshold dose is determined by the effect of two loci. The direction of the dominance effect also varies with the antigen dose: high responsiveness is partially dominant at the optimal dose while at the threshold dose nonresponder character is partially dominant. The role of theH-2 linked locus was investigated. It has been demonstrated that on an identical background (equivalent to that of F1 hybrids) this locus is responsible for 12% of the interline difference at the optimal antigen dose, and for 61% at the threshold antigen dose. For the two antigen doses, the quantitative effect of theH-2 locus is in agreement with the estimate of the number of loci obtained by variance analysis. The intervention of a second gene, non-H-2 linked, in the regulation of responsiveness to 106 SE is demonstrated by appropriate assortative matings. The interaction between the two genes is discussed. 相似文献
994.
Ronald L. Sollock Jean E. Vorhaben James W. Campbell 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1979,129(2):129-135
Summary Hepatopancreas tissue from the terrestrial snailsOtala lactea, Helix aspersa andStrophocheilus oblongus and the aquatic snailsBiomphalaria glabrata, Viviparus viviparus andLymnaea stagnalis was investigated for the presence of the various transaminases and glutamate dehydrogenase (EC 1.4.1.2 L-glutamate: NAD+ oxidoreductase). The cytosolic transaminases showed a broad substrate specificity, transferring the -amino function of most amino acids to -ketoglutarate. The main transaminase activities present were those of asparate transaminase (EC 2.6.1.1 L-aspartate: 2-oxoglutarate aminotransferase) and alanine transaminase (EC 2.6.1.2 L-alanine: 2-oxoglutarate aminotransferase). These two transaminases were also present in the mitochondrial fraction and thus exist in gastropod hepatopancreas as isozymes.Low levels of glutamate dehydrogenase activity were detected in hepatopancreas mitochondria from terrestrial and aquatic snails. The activity appears to be that of a typical animal glutamate dehydrogenase, preferentially utilizing NAD+ as a cofactor and being activated by adenine nucleotides and inhibited by guanine nucleotides.Supported by grants from the USPHS (AI 05006 and DE-00118) and the NSF (GB-38138) 相似文献
995.
Purification and properties of human erythrocyte delta-amino-levulinic acid dehydratase (EC 4-2-1-24) 总被引:2,自引:0,他引:2
Human delta-aminolevulinic acid dehydratase (ALA-D) was purified 9 000-fold by salt precipitation, ion-exchange chromatography and gel filtration. These methods resulted into an electrophoretically and immunologically pure protein. The optimum pH of the enzyme is 6.6 and its Km with ALA : 4.8 X 10(-4) M. The enzymatic activity was increased by thiol-containing substances, such as dithiothreitol (DTT), which protect the -SH groups of the protein. Zinc, a portion of the enzyme molecule, was partly lost during the purification procedure; its addition enhances the enzymatic activity. Determination of molecular weights and electron microscopy study are in favor of an octameric structure. 相似文献
996.
Summary The localization in the mouse brain of corticosterone, the natural glucocorticoid in the mouse, and cortexolone, reported to be a glucocorticoid antagonist, was studied by autoradiography 30 min after in vivo administration of the tritiated compounds.After 3H-corticosterone (3HB) injection, radioactivity was preferentially concentrated in cell nuclei of several structures within the limbic system, and in nuclei of certain neurones of the cerebral cortex and medulla oblongata. This nuclear concentration was abolished after injection of 3H-corticosterone with an excess of unlabelled corticosterone. After 3H-cortexolone (3HS) injection, a diffuse radioactivity was observed throughout the brain. However, a higher concentration of grains was present in the ventral nucleus arcuatus and in the infundibulum. When excess unlabelled cortexolone was administered with 3H-cortexolone this preferential accumulation of grains was abolished.The accumulation of 3H-cortexolone in the medial basal hypothalamic region suggests that cortexolone concentrates preferentially in dexamethasone (DM) target regions, and in addition the autoradiographic results show that the cortexolone-receptor complex does not accumulate in the cell nucleus.
Résumé La localisation au niveau du cerveau de souris de la corticostérone, qui est le glucocorticoide naturel chez la souris, et de la cortexolone, démontrée comme étant un antagoniste des glucocorticoides, est étudiée par autoradiographie 30 min après injection in vivo des composés tritiés.Après injection de 3H-corticosterone (3HB), la radioactivité se concentre préférentiellement dans des noyaux cellulaires de plusieurs structures du système limbique et dans les noyaux de certains neurones du cortex cérébral et du bulbe rachidien. Cette concentration nucléaire est abolie après injection de 3H-corticostérone en présence d'un excès de corticostérone non radioactive. Après injection de 3H-cortexolone (3HS), une distribution diffuse de la radioactivité est observée dans tout le cerveau, cependant, une concentration plus élevée de grains d'argent est présente dans la partie ventrale du nucleus arcuatus et dans l'infundibulum. Après injection de 3H-cortexolone en présence d'un excès de cortexolone non radioactive, cette accumulation préférentielle des grains est abolie.L'accumulation de la 3H-cortexolone dans la région hypothalamique suggère que la cortexolone se concentre préférentiellement dans la région cérébrale qui contient les sites de liaison de la dexaméthasone et de plus, les résultats autoradiographiques montrent que le complexe cortexolone-récepteur ne s'accumule pas dans le noyau cellulaire.相似文献
997.
Summary Autoradiograms of mouse pituitaries were prepared 30 min after injection of 3H-dexamethasone (3HDM), 3H-corticosterone (3HB) and 3H cortexolone (3HS) either alone or in the presence of competing unlabelled steroids. 3H-dexamethasone accumulated in cell nuclei of both the pars distalis and the pars nervosa but not in those of the pars intermedia. This preferential accumulation (nuclear/cytoplasmic grain density, 41) was abolished by the concurrent administration of excess dexamethasone. 3H-corticosterone, to a much less marked extent than 3H-dexamethasone, accumulated in cell nuclei of the pars distalis but not in those of the pars intermedia and the pars nervosa. Excess unlabelled corticosterone diminished nuclear grain density in the pars distalis. After 3H-cortexolone injection, preferential nuclear uptake was not observed. In a second series of experiments, excess dexamethasone (10 x, 100 x), corticosterone (100 x, 300 x) and cortexolone (100 x, 300 x) administered with 3H-dexamethasone were without effect on cytoplasmic grain density but totally abolished preferential nuclear accumulation. Parallel biochemical studies on kidney cytoplasmic preparations from the same animals showed no differences in total cytoplasmic radioactivity between treatments but marked differences in cytoplasmic bound 3H-dexamethasone. The results demonstrate: i) that dexamethasone binds specifically to cell nuclei of the pars distalis and the pars nervosa and that this nuclear concentration is abolished by competing corticosterone and cortexolone as well as dexamethasone; ii) that corticosterone localizes in cell nuclei of the pars distalis but much less markedly than dexamethasone; iii) that cortexolone fullfils the criteria of a glucocorticoid antagonist at the pituitary cell level.
Résumé La localisation au niveau de l'hypophyse de souris de la 3H-dexaméthasone (3HDM), de la 3H-corticostérone (3HB) et de la 3H-cortexolone (3HS) est étudiée par autoradiographie 30 min après l'injection des composés tritiés seuls ou en présence de stéroides compétiteurs non radioactifs. La 3H-dexaméthasone s'accumule dans des noyaux cellulaires de la pars distalis et de la pars nervosa mais pas dans des noyaux de la pars intermédia. Cette accumulation préférentielle (densité des grains d'argent nucléaire/cytoplasmique: 4/1) est abolie par l'injection de 3H-dexaméthasone en présence de dexaméthasone non radioactive. La 3H-corticostérone se concentre avec une intensité beaucoup plus faible que la 3H-dexaméthasone uniquement dans certains noyaux de la pars distalis. Un excès de corticostérone non radioactive diminue la densité nucléaire des grains d'argent des cellules de la pars distalis. Après injection de 3H-cortexolone, aucune accumulation préférentielle de grains d'argent n'est observée dans les noyaux cellulaires. Dans une seconde série d'expériences, la 3H-dexaméthasone est injectée soit en présence d'excès de dexaméthasone (10x, 100x) ou de corticostérone (100x, 300x) ou de cortexolone (100 x, 300 x). Dans ces conditions, la densité cytoplasmique des grains d'argent n'est pas différente de celle observée après injection de 3H-dexaméthasone seule mais l'accumulation préférentielle de la radioactivité dans les noyaux cellulaires est abolie. Des études biochimiques parallèles effectuées sur des préparations cytoplasmiques de rein des mêmes animaux montrent que la radioactivité cytoplasmique totale ne varie pas tandis que la liaison cytoplasmique de la 3H-dexaméthasone diffère suivant les traitements. Ces résultats montrent i) que la dexaméthasone se fixe spécifiquement dans des noyaux cellulaires de la pars distalis et de la pars nervosa et que cette fixation nucléaire est abolie aussi bien par des excés de corticostérone ou de cortexolone que par des excès de dexaméthasone, ii) que la corticostérone se localise dans des noyaux cellulaires de la pars distalis mais beaucoup moins intensément que la dexaméthasone, iii) que la cortexolone se comporte comme un antagoniste des glucocorticoides au niveau de la cellule hypophysaire.相似文献
998.
Jean Jew M.D. Bang-H. Hwang Dean Sandquist Terence H. Williams 《Cell and tissue research》1979,202(2):241-249
Summary The question of age as a possible factor influencing the regenerative response of catecholaminergic varicosities in the hypothalamus was investigated in the supraoptic commissure and the paraventricular, periventricular, and dorsomedial hypothalamic nuclei of rats that had received intraventricular injections of the neurotoxin 6-hydroxydopamine when they were (1) neonates, (2) young adults, or (3) senescent adults. After postneurotoxin survival for 4, 21, 56, or 180 days, the animals were perfused, and the hypothalamic tissue sections were cut and processed using a glyoxylic acid method for localizing catecholamines. Four days following neurotoxin administration, counts of fluorescent varicosities showed a significant loss of catecholamine varicosities in each of the four areas. Subsequently, at least partial restoration of numbers of catecholamine varicosities occurred in all hypothalamic areas in all three age groups. It is concluded that, following selective lesions induced by the neurotoxin 6-OH-DA, catecholamine varicosities were restored both in immature and mature groups. According to the evidence obtained experimentally, the rate of restoration was greater in the neonate group, whereas the percentage restoration attained varies according to the hypothalamic area studied and the age of the animal. 相似文献
999.
Cytochromes c
3 of different strains of sulfatereducing bacteria have been purified and tested for their capacity to reduce colloidal sulfur to hydrogen sulfide. The results are in good agreement with the activities reported for the whole cells. Cytochrome c
3 is the sulfur reductase of some strains of sulfate-reducing bacteria such as Desulfovibrio desulfuricans Norway 4 and sulfate-reducing bacterium strain 9974 from which the sulfur reductase activity can be purified with the cytochrome c
3. In contrast, Desulfovibrio vulgaris Hildenborough cytochrome c
3 is inhibited by the product of the reaction namely hydrogen sulfide. Chloramphenicol has no effect on the sulfur reductase activity of D. desulfuricans Norway 4 when resting cells grown on lactate-sulfate medium are put in the presence of colloidal sulfur. This shows that the sulfur reductase activity is constitutive and corresponds to the fact that colloidal sulfur grown cells do not contain more cytochrome c
3 (or another sulfur reductase) than lactate-sulfate-grown cells. 相似文献
1000.