Presumed Fact
Mostrando 13-24 de 25 artigos, teses e dissertações.
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13. Trypanosoma brucei mitochondria contain RNA helicase activity.
Mitochondrial gene expression in kinetoplastid organisms such as Trypanosoma, Leishmania and Crithidia requires a posttranscriptional RNA processing event known as kRNA editing. During editing, uridine nucleotides get inserted and deleted into pre-mRNAs directed by small, metabolically stable RNAs, termed guide RNAs. Although the precise mechanism of the rea
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14. Synaptic plasticity in rat hippocampal slice cultures: local "Hebbian" conjunction of pre- and postsynaptic stimulation leads to distributed synaptic enhancement.
A central theme in neurobiology is the search for the mechanisms underlying learning and memory. Since the seminal work, first of Cajal and later of Hebb, the synapse is thought to be the basic "storing unit." Hebb proposed that information is stored by correlation: synapses between neurons, which are often coactive, are enhanced. Several recent findings sug
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15. Discovery of the ergothioneine transporter
Variants of the SLC22A4 gene are associated with susceptibility to rheumatoid arthritis and Crohn's disease. SLC22A4 codes for an integral membrane protein, OCTN1, that has been presumed to carry organic cations like tetraethylammonium across the plasma membrane. Here, we show that the key substrate of this transporter is in fact ergothioneine (ET). Human OC
National Academy of Sciences.
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16. Genetic analysis of the dominant white-spotting (W) region on mouse chromosome 5: identification of cloned DNA markers near W.
We have assigned several mouse cDNA and genomic clones to the W region of mouse chromosome 5, established their position with respect to various marker loci in the region, and provided molecular verification that the W19H mutation is a deletion. Meiotic recombination analysis of an interspecific mouse backcross indicated the following gene order and distance
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17. Sequence-specific interaction with the viral AL1 protein identifies a geminivirus DNA replication origin.
The bipartite geminiviruses such as tomato golden mosaic virus (TGMV) and squash leaf curl virus (SqLCV) have two single-stranded circular genomic DNAs, the A and B components, thought to be replicated from double-stranded circular DNA intermediates. Although it has been presumed that the origin sequences for viral replication are located in the highly conse
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18. Immunoglobulin M antibodies to hepatitis B core antigen: evaluation of enzyme immunoassay for diagnosis of hepatitis B virus infection.
In acute and chronic hepatitis B, antibodies of the immunoglobulin M (IgM) class against the hepatitis B core antigen (anti-HBc IgM) have been demonstrated. For the determination of anti-HBc IgM, a sensitive enzyme immunoassay with anti-mu-coated flat-bottomed microtiter plates is described and evaluated. The specificity of the anti-HBc IgM test system was p
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19. Evaluation of the Recombigen HIV-1 Latex Agglutination Test.
The Recombigen HIV-1 Latex Agglutination (LA) Test was recently licensed by the U.S. Food and Drug Administration for use as a rapid screening assay for human immunodeficiency virus type 1 (HIV-1) antibodies. However, its performance in various settings and in different populations has not been firmly established. Consequently, we evaluated the test in the C
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20. Spontaneous splicing mutations at the dihydrofolate reductase locus in Chinese hamster ovary cells.
We isolated and characterized three spontaneous mutants of Chinese hamster ovary cells that were deficient in dihydrofolate reductase activity. All three mutants contained no detectable enzyme activity and produced dihydrofolate reductase mRNA species that were shorter than those of the wild type by about 120 bases. Six exons are normally represented in this
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21. rpoS Function Is Essential for bgl Silencing Caused by C-Terminally Truncated H-NS in Escherichia coli
From evolutionary and physiological viewpoints, the Escherichia coli bgl operon is intriguing because its expression is silent (Bgl− phenotype), at least under several laboratory conditions. H-NS, a nucleoid protein, is known as a DNA-binding protein involved in bgl silencing. However, we previously found that bgl expression is still silent in a certain su
American Society for Microbiology.
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22. SH2 Domain-Mediated Interaction of Inhibitory Protein Tyrosine Kinase Csk with Protein Tyrosine Phosphatase-HSCF
The protein tyrosine kinase (PTK) Csk is a potent negative regulator of several signal transduction processes, as a consequence of its exquisite ability to inactivate Src-related PTKs. This function requires not only the kinase domain of Csk, but also its Src homology 3 (SH3) and SH2 regions. We showed previously that the Csk SH3 domain mediates highly speci
American Society for Microbiology.
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23. Two divergent catalase genes are differentially regulated during Aspergillus nidulans development and oxidative stress.
Catalases are ubiquitous hydrogen peroxide-detoxifying enzymes that are central to the cellular antioxidant response. Of two catalase activities detected in the fungus Aspergillus nidulans, the catA gene encodes the spore-specific catalase A (CatA). Here we characterize a second catalase gene, identified after probing a genomic library with catA, and demonst
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24. Analysis of pre-rRNAs in heat-shocked HeLa cells allows identification of the upstream termination site of human polymerase I transcription.
Human rRNA precursor from normal or stressed HeLa cells were studied by S1 nuclease mapping of unlabeled RNA and by antisense RNase mapping of RNA from cells that had been labeled in vivo with [32P]PO4. Heating cells to 43 degrees C decreased the amount of newly synthesized rRNA to less than 5% of the control level and led to greater than 95% inhibition of t