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The protein–nanomaterial interface 总被引:1,自引:1,他引:0
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A Kanté M Cherkaoui-Malki A Bailly P Adami N Latruffe 《Comptes rendus des séances de la Société de biologie et de ses filiales》1987,181(4):389-394
beta-hydroxybutyrate dehydrogenase (BDH), a major protein located in the inner mitochondrial membrane is encoded, as most of mitochondrial proteins, in the nuclear genome. It is synthetized on the free polysomes and post-translationally imported into the mitochondria. The neosynthesized protein is a higher molecular weight precursor. The presequence is cleaved by the matrix protease to give the mature protein. The translocation across the mitochondrial membranes needs energy. The results also indicate that cytosolic factors with low molecular weight are essential in the recognition of precursor by mitochondria and to sort out newly synthetized nuclear encoded mitochondrial proteins from others nuclear encoded proteins. 相似文献
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A Bailly A Kanté M Cherkaoui-Malki P Adami N Latruffe 《Comptes rendus des séances de la Société de biologie et de ses filiales》1987,181(5):506-512
In order to continue the molecular studies of D-beta-hydroxybutyrate dehydrogenase (BDH) undertaken in our laboratory for several years, we have initiated a genetic approach which consists in the BDH cDNA cloning from a rat liver cDNA library. The immunoscreening method allowed to isolate a clone which exhibits a DNA insert shorter than the expected full length BDH cDNA. 相似文献
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The effects of histamine on the activity of rapidly adapting receptors (RAR) of the airways were investigated in anesthetized dogs. With bolus injections given into the right atrium, the threshold dose of histamine required for the excitation of RAR (n = 7) was 0.82 microgram/kg (+1.33/-0.51, geometric mean). With increasing doses of histamine, a dose-response relationship was seen in the activity of RAR. Obstruction of the lymphatic drainage from the lungs reduced the threshold dose to histamine (i.e., shifted the dose-response curve to the left significantly). This change in the dose-response relationship was not accompanied by a corresponding change in the relationship of histamine dose to airway pressures recorded before and after lymphatic obstruction. Against a background of pulmonary venous congestion produced by partial obstruction of the mitral valve, subthreshold doses of histamine stimulated the RAR (n = 4). The excitatory effect of histamine on RAR was found to be abolished by the administration of the H1 receptor antagonist diphenhydramine but not by the H2 receptor antagonist cimetidine. Intravenous infusion of histamine (0.4 microgram.kg-1.min-1) for a period of 10 min increased the RAR activity (n = 6) significantly without producing detectable changes in airway mechanics. The results indicate that contraction of the smooth muscle of the airways may not be a prerequisite for the excitation of RAR, especially at low doses. It is suggested that some of the effects of histamine on RAR are mediated by a local expansion of the extravascular fluid caused by an increase in the permeability of the bronchial vasculature. 相似文献
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Advantages of firefly luciferase as a reporter gene: application to the interleukin-2 gene promoter 总被引:4,自引:0,他引:4
The chloramphenicol acetyltransferase (CAT) gene is widely used in recombinant constructs employed to study promoter and enhancer control of gene expression. However, CAT-based assays require a laborious, multi-step procedure for quantitation of promoter activity. We have applied the recently described firefly luciferase (LUC) reporter gene to the study of the interleukin-2 (IL2) promoter and have further defined the properties of this reporter gene system. We find that IL2-LUC constructs have multiple advantages over IL2-CAT constructs. The LUC assay is highly sensitive and requires 1/10 the cells used in the CAT system. A final quantitative measure of promoter activity can be obtained within 25 h following transfection with IL2-LUC, compared to 108-160 h with IL2-CAT. Light emission significantly (fourfold) above background is detectable 3 h after induction in a direct assay of extracts from transfected cells. We have described the variability of the assay, the minimum number of transfected cells required to detect light, the stability of luciferase in cell extracts, the effect of Triton X-100 on the assay, and a rapid cell lysis procedure. The luciferase system is a simple, rapid, and sensitive method for the study of promoter activity in transfected cells, particularly for weakly expressed genes such as IL2 which give low activity in the CAT assay. 相似文献
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Depletion of the spermatogonia from the seminiferous epithelium of the rhesus monkey after X irradiation 总被引:4,自引:0,他引:4
In unirradiated testes large differences were found in the total number of spermatogonia among different monkeys, but the number of spermatogonia in the right and the left testes of the same monkey appeared to be rather similar. During the first 11 days after irradiation with 0.5 to 4.0 Gy of X rays the number of Apale spermatogonia (Ap) decreased to about 13% of the control level, while the number of Adark spermatogonia (Ad) did not change significantly. A significant decrease in the number of Ad spermatogonia was seen at Day 14 together with a significant increase in the number of Ap spermatogonia. It was concluded that the resting Ad spermatogonia are activated into proliferating Ap spermatogonia. After Day 16 the number of both Ap and Ad spermatogonia decreased to low levels. Apparently the new Ap spermatogonia were formed by lethally irradiated Ad spermatogonia and degenerated while attempting to divide. The activation of the Ad spermatogonia was found to take place throughout the cycle of the seminiferous epithelium. Serum FSH, LH, and testosterone levels were measured before and after irradiation. Serum FSH levels already had increased during the first week after irradiation to 160% of the control level. Serum LH levels increased between 18 and 25 days after irradiation. Serum testosterone levels did not change at all. The results found in the rhesus monkey are in line with those found in humans, but due to the presence of Ad spermatogonia they differ from those obtained in non-primates. 相似文献
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A J Fornace D E Cummings C M Comeau J A Kant G R Crabtree 《The Journal of biological chemistry》1984,259(20):12826-12830
The gamma chain of human fibrinogen exists in 2 nonallelic forms, gamma A and gamma B, which differ only in their carboxyl termini. We have found that only one genomic locus exists for gamma-fibrinogen and that the gamma A and gamma B chains arise by alternate mRNA splicing near the 3' end of this gene. In contrast to the rat gamma B mRNA which is produced by alternate splicing with identical polyadenylation sites, human gamma B is produced when the eighth intervening sequence remains unspliced and a polyadenylation signal within this intron is used. The new carboxyl terminus is 16 amino acids longer than the gamma A protein, and although there is only minimal homology between the rat and human carboxyl termini they share a very high proportion of acidic amino acids. 相似文献