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1.
Platelet activating factor induces expression of early response genes c-fos and TIS-1 in human epidermoid carcinoma A-431 cells 总被引:2,自引:0,他引:2
The effect of platelet activating factor (PAF) on the induction of early response genes was investigated in A-431 cells (human epidermal carcinoma cells). PAF induced a transient expression of c-fos and TIS-1 mRNA in a time- and dose-dependent manner. As low as 10(-10) M PAF caused detectable expression of these genes with a maximum observed at 10(-7) M. In the presence of cycloheximide, increases in the gene expression were noticeable at 20 min and peaked between 30-60 min. A lack of induction with lyso-PAF, an inactive PAF metabolite, confirmed the specificity of PAF towards this expression. The cells pretreated with CV-6209, a PAF receptor antagonist, did not show any induction of these genes by PAF. It is concluded that PAF causes induction of the early response genes c-fos and TIS-1 in a structurally specific and receptor dependent manner. This finding offers a new role for PAF at the nuclear level and may have important implications in the long term effects of PAF in pathophysiological conditions. 相似文献
2.
Organization of Plasmodium falciparum genome: 1. Evidence for a highly repeated DNA sequence. 总被引:3,自引:1,他引:2
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Plasmodium falciparum DNA, isolated from the merozoite stage, was cleaved with HindIII and cloned in pBR322 and lambda L47.1 vectors. Plasmid clones containing 13.4, 7.0, 4.3, 4.1 and 1.5 kb inserts were characterized in some detail. The inserts contain several repeating units of smaller size. Nucleic acid hybridization studies showed that the repeat element is present in the Plasmodium DNA at a very high copy number and appears to be distributed widely throughout the genome. 相似文献
3.
Specific Loss of Newly Replicated Deoxyribonucleic Acid in Nalidixic Acid-Treated Bacillus subtilis 168 总被引:13,自引:6,他引:7
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Bacillus subtilis 168 thyA, thyB cells degrade and lose from 20 to 30% of their deoxyribonucleic acid (DNA) in 3.5 hr of exposure to 20 mug of nalidixic acid per ml. Degradation appears to be initiated at the replication point and to proceed sequentially along the chromosome from the most recently synthesized DNA to "older" DNA. Both DNA strands appear to be degraded equally, and essentially all of the products of degradation are soluble in cold acid. 相似文献
4.
Restriction endonuclease and nucleotide sequence analyses of molecularly cloned unintegrated avian tumor virus DNA: structure of large terminal repeats in circle junctions 总被引:39,自引:29,他引:10
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R A Katz C A Omer J H Weis S A Mitsialis A J Faras R V Guntaka 《Journal of virology》1982,42(1):346-351
Avian tumor virus supercoiled DNA was isolated from infected quail tumor cells and molecularly cloned in pBR322. Four different recombinant clones denoted pATV-6, pATV-7, pATV-8, and pATV-9 were characterized in detail by restriction endonuclease mapping and by DNA sequencing. The results of these studies indicate that (i) the two large terminal repeats (LTRs) present in PATV-6, are different sizes, (ii) pATV-8 and pATV-9 contain only one LTR, (iii) pATV-7 contains an inversion of 0.6 kilobase in the env gene and a deletion of the U3 region and the src gene, and (iv) the src gene is deleted in pATV-6 and pATV-9. Circle formation from linear molecules was also examined in several of the clones by DNA sequencing through the circle joint. pATV-6 is an example of one class of circular molecules and contains a partially repeated LTR similar to that reported by Ju and Skalka (Cell 22:379-386, 1980). A second class of circles was exemplified by pATV-8 and pATV-9, which contain a single copy of the LTR with no base changes or deletions. This is in contrast to a class of circles containing a complete double LTR structure described by Swanstrom et al. (Proc. Natl. Acad. Sci. U.S.A. 78:124-128, 1981) and suggests that circles containing a single intact LTR may be formed by a homologous recombinational event in which an entire LTR or complementary regions from both LTRs are removed from the linear DNA molecule during circularization. 相似文献
5.
Specific site of action for single-strand specific nuclease on the double-stranded circular DNA intermediates of an avian RNA tumor virus. 总被引:4,自引:1,他引:3
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Circular viral DNA intermediates obtained from the quail tumor line, QT6, at 1 day after infection, were opened at one specific location by the single-strand specific nuclease, S1, of Aspergillus oryzae. This site was no longer accessible to the S1 nuclease when circles were first opened at another location with a restriction endonuclease. 相似文献
6.
Analysis of unintegrated avian RNA tumor virus double-stranded DNA intermediates. 总被引:88,自引:60,他引:28
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Previous studies by Guntaka et al. have shown that the unintegrated DNA intermediates of avian RNA tumor virus replication can be readily isolated from cultures of the quail tumor line QT-6 at 1 day after infection. The intermediates include double-stranded linear and covalently closed circular DNA species. Using the analysis procedure of Southern together with previously obtained information regarding the sites of action of certain restriction endonucleases on avian sarcoma virus DNA, we have further characterized the viral DNA intermediates. Evidence is presented that, relative to the RNA genome, most of the linear species possess a direct terminal sequence redundancy equivalent to 0.5 X 10(6) +/- 0.3 X 10(6) daltons of double-stranded DNA. Some of the circular forms also possess a sequence redundancy of 0.21 X 10(6) +/- 0.03 X 10(6) daltons. 相似文献
7.
Modification of avian sarcoma proviral DNA sequences in nonpermissive XC cells but not in permissive chicken cells 总被引:16,自引:7,他引:9
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For the first time, we present evidence with restriction enzymes HpaII and MspI which indicates that the proviral DNA sequence of avian sarcoma virus is modified by methylation in a nonpermissive rat cell line but not in permissive chicken cells. Some of the endogenous viral sequences in the permissive cells were also methylated. No 5-methylcytosine could be detected in the unintegrated viral DNA. 相似文献
8.
Roseane Borner Jo?o Bento-Torres Diego RV Souza Danyelle B Sadala Nonata Trevia José Augusto Farias Nara Lins Aline Passos Amanda Quintairos José Ant?nio Diniz Victor Hugh Perry Pedro Fernando Vasconcelos Colm Cunningham Cristovam W Pican?o-Diniz 《朊病毒》2011,5(3):215-227
Behavioral and neuropathological changes have been widely investigated in murine prion disease but stereological based unbiased estimates of key neuropathological features have not been carried out. After injections of ME7 infected (ME7) or normal brain homogenates (NBH) into dorsal CA1 of albino Swiss mice and C57BL6, we assessed behavioral changes on hippocampal-dependent tasks. We also estimated by optical fractionator at 15 and 18 weeks post-injections (w.p.i.) the total number of neurons, reactive astrocytes, activated microglia and perineuronal nets (PN) in the polymorphic layer of dentate gyrus (PolDG), CA1 and septum in albino Swiss mice. On average, early behavioral changes in albino Swiss mice start four weeks later than in C57BL6. Cluster and discriminant analysis of behavioral data in albino Swiss mice revealed that four of nine subjects start to change their behavior at 12 w.p.i. and reach terminal stage at 22 w.p.i and the remaining subjects start at 22 w.p.i. and reach terminal stage at 26 w.p.i. Biotinylated dextran-amine BDA-tracer experiments in mossy fiber pathway confirmed axonal degeneration and stereological data showed that early astrocytosis, microgliosis and reduction in the perineuronal nets are independent of a change in the number of neuronal cell bodies. Statistical analysis revealed that the septal region had greater levels of neuroinflammation and extracellular matrix damage than CA1. This stereological and multivariate analysis at early stages of disease in an outbred model of prion disease provided new insights connecting behavioral changes and neuroinflammation and seems to be important to understand the mechanisms of prion disease progression.Key words: prion disease, optical fractionator, neuropathology, behavioral changes, albino Swiss mice 相似文献
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10.
Sequence-specific triple helix formation with genomic DNA 总被引:1,自引:0,他引:1