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Ribonucleic Acid Polymerase Induced by Vaccinia Virus: Lack of Inhibition by Rifampicin and α-Amanitin
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F. Costanzo L. Fiume M. La Placa Anna Mannini-Palenzona F. Novello F. Stirpe 《Journal of virology》1970,5(2):266-269
The RNA polymerase activity present in the cytoplasm of BHK cells infected with vaccinia virus is not affected by rifampicin or by alpha-amanitin. 相似文献
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Erin E. Cummings Linda P. O’Reilly Dale E. King Richard M. Silverman Mark T. Miedel Cliff J. Luke David H. Perlmutter Gary A. Silverman Stephen C. Pak 《PloS one》2015,10(10)
α1-antitrypsin deficiency (ATD) predisposes patients to both loss-of-function (emphysema) and gain-of-function (liver cirrhosis) phenotypes depending on the type of mutation. Although the Z mutation (ATZ) is the most prevalent cause of ATD, >120 mutant alleles have been identified. In general, these mutations are classified as deficient (<20% normal plasma levels) or null (<1% normal levels) alleles. The deficient alleles, like ATZ, misfold in the ER where they accumulate as toxic monomers, oligomers and aggregates. Thus, deficient alleles may predispose to both gain- and loss-of-function phenotypes. Null variants, if translated, typically yield truncated proteins that are efficiently degraded after being transiently retained in the ER. Clinically, null alleles are only associated with the loss-of-function phenotype. We recently developed a C. elegans model of ATD in order to further elucidate the mechanisms of proteotoxicity (gain-of-function phenotype) induced by the aggregation-prone deficient allele, ATZ. The goal of this study was to use this C. elegans model to determine whether different types of deficient and null alleles, which differentially affect polymerization and secretion rates, correlated to any extent with proteotoxicity. Animals expressing the deficient alleles, Mmalton, Siiyama and S (ATS), showed overall toxicity comparable to that observed in patients. Interestingly, Siiyama expressing animals had smaller intracellular inclusions than ATZ yet appeared to have a greater negative effect on animal fitness. Surprisingly, the null mutants, although efficiently degraded, showed a relatively mild gain-of-function proteotoxic phenotype. However, since null variant proteins are degraded differently and do not appear to accumulate, their mechanism of proteotoxicity is likely to be different to that of polymerizing, deficient mutants. Taken together, these studies showed that C. elegans is an inexpensive tool to assess the proteotoxicity of different AT variants using a transgenic approach. 相似文献
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D. C. S. Hutchinson P. J. L. Cook C. E. Barter Harry Harris P. Hugh-Jones 《BMJ (Clinical research ed.)》1971,1(5751):689-694
Of 72 patients with radiological evidence of pulmonary emphysema, emphysema occurred either alone or in association with bronchitis in 61, and 8 of these (13%) were found to have α1-antitrypsin deficiency. The main features of this condition are: exertional dyspnoea of relatively early onset (generally between 30 and 45 years of age), severely impaired FEV1 and TLCO, and radiological emphysema predominantly affecting the lower zones of the lungs. It is probable that any patient with all the above abnormalities has α1-antitrypsin deficiency. There is evidence to suggest that cigarette smoking may hasten the onset of this type of emphysema. 相似文献
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NADA LEDINKO 《Nature: New biology》1971,233(42):247-248
ADENOVIRUS infection of human embryonic kidney (HEK) cultures seems to induce cellular RNA synthesis, which is preceded by a transient increase in the activities of the Mg2+-activated and Mn2+-(NH4)2SO4-activated DNA dependent RNA polymerases and in the rate of histone acetylation1. The two polymerase reactions, assayed in isolated cell nuclei, apparently reflect the activities of distinct nucleolar and nucleo-plasmic RNA polymerases2,3. We were therefore prompted to test the effect of a specific inhibitor of the mammalian DNA-dependent RNA polymerase function, α-amanitin, on the multiplication of adenovirus. α-Amanitin is a bicyclic octapeptide isolated from the poisonous mushroom Amanita phalloides4 and which blocks RNA synthesis in intact animals5,6. Nuclei isolated from the livers of such animals show a reduced activity of the RNA polymerases associated with nucleoplasm5,6 and the nucleolus6. 相似文献
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Senarath B. P. Athauda Masaaki Nishigai Hideo Arakawa Atsushi Ikai Masanori Ukai Kenji Takahashi 《Journal of enzyme inhibition and medicinal chemistry》2013,28(3):219-224
The inhibitory effects of human α2-macroglobulin (α2-M), a major plasma proteinase inhibitor, on human pepsin and gastricsin were investigated. The activities of pepsin and gastricsin towards a protein substrate (reduced and carboxymethylated ribonuclease A) were significantly inhibited by α2-M at pH 5.5, whereas those towards a peptide substrate (oxidized insulin B-chain) were scarcely inhibited. Under these conditions at pH 5.5, pepsin and gastricsin cleaved α2-M mainly at the His694-Ala695 bond and Leu697-Val698 bond, respectively, in the bait regions sequence of α2-M. The conformation of α2-M was also shown to be markedly altered upon inhibition of these enzymes as examined by native polyacrylamide gel electrophoresis and electron microscopy. These results show the entrapment and concomitant inhibition of those proteinases by α2-M. 相似文献
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Summary The specific activity of thirteen genetic variants of the protease inhibitor 1-antitrypsin (1-AT) has been determined. Elastase inhibitor activity was assayed using protein substrates (elastin and gelatin) and the synthetic substrate N-tert-butoxycarbonyl-l-alanine p-nitrophenyl ester. The synthetic substrate -N-benzoyl-dl-arginine p-nitroanilide HCl was used to assay trypsin inhibitor activity. The specific activity of 1-AT was expressed as serum inhibition/immunological concentration of 1-AT. Sera of PI type FM had reduced specific activity with elastase, but not with trypsin. With the possible exception of MP, no other variants showed significant differences in specific activity when compared with normal PI type M.This research was supported by the Medical Research Council of Canada (No. MA 5426) 相似文献
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Mariela Resendes 《The Western journal of medicine》1987,147(1):48-53
α1-Protease inhibitor (α1-Pi) deficiency is associated with emphysema, neonatal hepatitis and cirrhosis. The deficiency associated with emphysema has multiple alleles. Cigarette smoke may influence the onset of emphysema in a twofold manner: by overwhelming the concentration of α1-Pi by increasing elastase release, and by inactivating the α1-Pi active site through oxidation. α1-Pi-associated hepatic disease occurs primarily in children with the allele PiZZ, most of whom are asymptomatic although in a small percentage severe obstructive jaundice and fatal junvenile cirrhosis develop. Pharmacologic intervention and α1-Pi replacement therapy are being tested against α1-Pi-associated emphysema. 相似文献
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《Bioscience, biotechnology, and biochemistry》2013,77(10):1904-1908
Thermostabilities of component enzymes in the pyruvate dehydrogenase complex from Bacillus stearothermophilus decreased in the order lipoamide dehydrogenase, lipoate acetyltransferase, and pyruvate decarboxylase (E1). Fluorescence of an extrinsic 8-amino-1-naphthalenesulfonate (ANS) increased with inactivation of E1. The thermal denaturation of the enzymes resulted in disassembly of the complex. El was involved in a resulting aggregate of the complex. The interaction between ANS and denatured E1 accounted for an increase in fluorescence. 相似文献
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Summary Three new rare genetic variants of the serum protein 1-antitrypsin (1-protease inhibitor) have been identified in a Caucasian population. The new alleles in the PI system are PI
*EFRA, PT*PCAS, and PI
*XALB. When compared with the normal type M by isoelectric focusing in polyacrylamide, Efranklin (EFRA) is anodal, and Pcastoria (PCAS) and Xalban (XALB) are cathodal. These variants have been compared with previously described variants by isoelectric focusing and by electrophoresis in agarose and acid starch gels. All three variant alleles appear to be associated with normal amounts of 1-antitrypsin, assayed both by functional and immunological methods.This work was supported by a grant from the Medical Research Council of Canada 相似文献
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Siyoung Lee Youngmin Lee Kwangwon Hong Jaewoo Hong Suyoung Bae Jida Choi Hyunjhung Jhun Areum Kwak Eunsom Kim Seunghyun Jo Charles A Dinarello Soohyun Kim 《Molecular medicine (Cambridge, Mass.)》2013,19(1):65-71
α1-Antitrypsin (AAT) is a member of the serine proteinase inhibitor family that impedes the enzymatic activity of serine proteinases, including human neutrophil elastase, cathepsin G and neutrophil proteinase 3. Here, we expressed recombinant AAT by fusing the intact AAT gene to the constant region of IgG1 to generate soluble recombinant AAT-Fc protein. The recombinant AAT-Fc protein was produced in Chinese hamster ovary (CHO) cells and purified using mini-protein A affinity chromatography. Recombinant AAT-Fc protein was tested for antiinflammatory function and AAT-Fc sufficiently suppressed tumor necrosis factor (TNF)-α–induced interleukin (IL)-6 in human peripheral blood mononuclear cells (PBMCs) and inhibited cytokine-induced TNFα by different cytokines in mouse macrophage Raw 264.7 cells. However, AAT-Fc failed to suppress lipopolysaccharide-induced cytokine production in both PBMCs and macrophages. In addition, our data showed that AAT-Fc blocks the development of hyperglycemia in a streptozotocin-induced mouse model of diabetes. Interestingly, we also found that plasma-derived AAT specifically inhibited the enzymatic activity of elastase but that AAT-Fc had no inhibitory effect on elastase activity. 相似文献
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Aggregation of alpha-synuclein (αS) into oligomers is critically involved in the pathogenesis of Parkinson's disease (PD). Using confocal single-molecule fluorescence spectroscopy, we have studied the effects of 14 naturally-occurring polyphenolic compounds and black tea extract on αS oligomer formation. We found that a selected group of polyphenols exhibited potent dose-dependent inhibitory activity on αS aggregation. Moreover, they were also capable of robustly disaggregating pre-formed αS oligomers. Based upon structure-activity analysis, we propose that the key molecular scaffold most effective in inhibiting and destabilizing self-assembly by αS requires: (i) aromatic elements for binding to the αS monomer/oligomer and (ii) vicinal hydroxyl groups present on a single phenyl ring. These findings may guide the design of novel therapeutic drugs in PD. 相似文献
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Kinetic changes of alpha-glucosidase from Saccharomyces cerevisiae in guanidinium chloride (GdmCl) and SDS solutions were investigated. The results showed both denaturants can lead conformational changes and loss of enzymatic activities. However, the concentrations of denaturants causing loss of activities were much lower than that of conformational changes, which suggested that the conformation of active site of α-glucosidase was more fragile than the whole molecular conformation in response to the two denaturants. According to the different kinetic process of the enzyme in the GdmCl and SDS solutions, the further investigation on the process of denaturation were made, it showed GdmCl and SDS had different types of inhibition and different types of interaction with the enzyme. Furthermore, the mechanisms of the two denaturants were discussed. 相似文献
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Demirkhanyan LH Marin M Padilla-Parra S Zhan C Miyauchi K Jean-Baptiste M Novitskiy G Lu W Melikyan GB 《The Journal of biological chemistry》2012,287(34):28821-28838
The human neutrophil peptide 1 (HNP-1) is known to block the human immunodeficiency virus type 1 (HIV-1) infection, but the mechanism of inhibition is poorly understood. We examined the effect of HNP-1 on HIV-1 entry and fusion and found that, surprisingly, this α-defensin inhibited multiple steps of virus entry, including: (i) Env binding to CD4 and coreceptors; (ii) refolding of Env into the final 6-helix bundle structure; and (iii) productive HIV-1 uptake but not internalization of endocytic markers. Despite its lectin-like properties, HNP-1 could bind to Env, CD4, and other host proteins in a glycan- and serum-independent manner, whereas the fusion inhibitory activity was greatly attenuated in the presence of human or bovine serum. This demonstrates that binding of α-defensin to molecules involved in HIV-1 fusion is necessary but not sufficient for blocking the virus entry. We therefore propose that oligomeric forms of defensin, which may be disrupted by serum, contribute to the anti-HIV-1 activity perhaps through cross-linking virus and/or host glycoproteins. This notion is supported by the ability of HNP-1 to reduce the mobile fraction of CD4 and coreceptors in the plasma membrane and to precipitate a core subdomain of Env in solution. The ability of HNP-1 to block HIV-1 uptake without interfering with constitutive endocytosis suggests a novel mechanism for broad activity against this and other viruses that enter cells through endocytic pathways. 相似文献
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?X174 DNA synthesis as well as phage production was inhibited by rifampicin when added in early phase of infection. Rifampicin did not inhibit the formation of parental duplex replicative-form, RF, and it inhibited the synthesis of progeny RF under conditions where protein synthesis was not necessary to be synthesized continuously. In addition, replication of parental RF into progeny RF was inhibited by rifampicin under conditions where a high concentration of chloramphenicol did not affect the replication. Consequently, it could be concluded that RNA synthesis other than that required for protein synthesis was necessary for both the initiation and continuation of RF replication. 相似文献
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The inhibition of α-amylase from human saliva by polyphenolic components of tea and its specificity was investigated in vitro. Four kinds of green tea catechins, and their isomers and four kinds of their dimeric compounds (theaflavins) produced oxidatively during black tea production were isolated. They were (?)-epicatechin (EC), (?)-epigallocatechin (EGC), (?)-epicatechin gallate (ECg), (?)-epigallocatechin gallate (EGCg), (?)-catechin (C), (?)-gallocatechin (GC), (?)-catechin gallate (Cg), (?)-gallocatechin gallate (GCg), theaflavin (TF1), theaflavin monogallates (TF2A and TF2B), and theaflavin digallate (TF3). Among the samples tested, EC, EGC, and their isomers did not have significant effects on the activity of α-amylase. All the other samples were potent inhibitors and the inhibitory effects were in the order of TF3>TF2A>TF2B>TFl>Cg> GCg > ECg > EGCg. The inhibitory patterns were noncompetitive except for TF3. 相似文献
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Summary Two groups of 708 healthy blood donors and 563 patients affected with chronic obstructive lung disease (C.O.L.D.) respectively, have been screened for 1-antitrypsin (1AT) variants by electrophoresis on agarose-polyacrylamide gels at pH 4.7 and isoelectric focusing (IEF).The frequencies of the Pi (Protease inhibitor) alleles are comparable to those observed in the North European populations. As expected, the frequency of the Z gene is higher in the group of patients with C.O.L.D. Also the frequency of MZ phenotypes is higher among these patients, but in this case the difference is not statistically significant.With the aid of the electrophoretic methods described in the text we were able to detect a new electrophoretic variant (M3) showing a mobility intermediate between the M1 and the M2 phenotypes. 相似文献