Pyrimidine And Purine
Mostrando 1-12 de 514 artigos, teses e dissertações.
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1. Pyrimidine alkaloids from Eudistoma vannamei
Abstract Methanolic extracts of the Brazilian endemic ascidian Eudistoma vannamei have been extensively studied for their cytotoxic activity against several human cancer cell lines. Previous work reported the occurrence of purine derivatives and staurosporine alkaloids as the major nitrogen-containing compounds. In this study, we report the occurrence of thr
Rev. bras. farmacogn.. Publicado em: 2015-12
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2. Modulatory effect of iron chelators on adenosine deaminase activity and gene expression in Trichomonas vaginalis
Trichomonas vaginalis is a flagellate protozoan that parasitises the urogenital human tract and causes trichomoniasis. During the infection, the acquisition of nutrients, such as iron and purine and pyrimidine nucleosides, is essential for the survival of the parasite. The enzymes for purinergic signalling, including adenosine deaminase (ADA), which degrades
Mem. Inst. Oswaldo Cruz. Publicado em: 23/10/2015
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3. Efeito dos diferentes níveis de nucleotídeos em frangos de corte alimentados com probióticos / Effect of the different nucleotides levels in broiler chickens fed with probitics
The objective of this experiment was to evaluate the influence of different nucleotides levels in the rations of broilers containing probiotics on response of the birds and its influence on the performance. Birds were allocated in a randomized experimental design with five replications of each treatment. It was used 1,050 chicks of a day of age, males, distr
Publicado em: 2009
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4. Purine and pyrimidine nucleotide metabolism in Mollicutes
Several mollicute genome projects are underway, offering unique opportunities to study genes and metabolic pathways on a genome-wide scale. Here, we have analyzed the conservation and diversity of purine and pyrimidine metabolism in mycoplasmas. An evaluation of discrepancies between genomic analysis and enzymatic data revealed interesting aspects about thes
Genetics and Molecular Biology. Publicado em: 2007
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5. Differential metabolism of Mycoplasma species as revealed by their genomes
The annotation and comparative analyses of the genomes of Mycoplasma synoviae and Mycoplasma hyopneumonie, as well as of other Mollicutes (a group of bacteria devoid of a rigid cell wall), has set the grounds for a global understanding of their metabolism and infection mechanisms. According to the annotation data, M. synoviae and M. hyopneumoniae are able to
Genetics and Molecular Biology. Publicado em: 2007
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6. Drosophila Rrp1 3'-exonuclease: demonstration of DNA sequence dependence and DNA strand specificity.
Drosophila Rrp1 (recombination repair protein 1) is a DNA repair enzyme whose nuclease activities include AP-endonuclease, 3'-exonuclease, 3'-phosphodiesterase and 3'-phosphatase. This study investigates the sequence specificity of the dsDNA 3'-exonuclease activity of Rrp1. We demonstrate that the activity is more efficient in purine-rich regions of dsDNA th
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7. Evidence from CD spectra that d(purine).r(pyrimidine) and r(purine).d(pyrimidine) hybrids are in different structural classes.
CD spectra and difference CD spectra of four d(oligopurine).r(oligopyrimidine) and four r(oligopurine).d(oligopyrimidine) hybrid duplexes containing mixed A.T(U) and G.C base pairs were compared with the spectra of four DNA.DNA and four RNA.RNA oligomer duplexes of similar repeating sequences. The 16 duplexes were formed by mixing oligomers that were 24 nucl
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8. DNA polymerase accuracy and spontaneous mutation rates: frequencies of purine.purine, purine.pyrimidine, and pyrimidine.pyrimidine mismatches during DNA replication.
DNA from the am16 mutant of bacteriophage phi X174 may be replicated in vitro and expressed in vivo to give five classes of revertants. Each class may be specifically induced by the appropriate biasing of the concentrations of deoxynucleoside triphosphates in a predictable manner. The frequency of each reversion follows a kinetic rate equation relating it to
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9. Exclusion of RNA strands from a purine motif triple helix.
Research concerning oligonucleotide-directed triple helix formation has mainly focused on the binding of DNA oligonucleotides to duplex DNA. The participation of RNA strands in triple helices is also of interest. For the pyrimidine motif (pyrimidine.purine.pyrimidine triplets), systematic substitution of RNA for DNA in one, two, or all three triplex strands
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10. Canine cyclic hematopoiesis is associated with abnormal purine and pyrimidine metabolism.
Canine cyclic hematopoiesis is an autosomal recessive disease characterized by regular 11-13-d cycles of the neutrophil, reticulocyte, and platelet counts caused by a defect in regulation of marrow stem cell proliferation. Treatment with lithium abrogates cycling of the cell counts in these grey collie dogs. Aware of the defective lymphopoiesis associated wi
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11. Different conformational families of pyrimidine.purine.pyrimidine triple helices depending on backbone composition.
Different helical conformations of DNA (D), RNA (R), and DNA.RNA (DR) hybrid double and triple helices have been detected using affinity cleavage analysis. Synthetic methods were developed to attach EDTA.Fe to a single nucleotide on RNA as well as DNA oligonucleotides. Cleavage patterns generated by a localized diffusible oxidant in the major groove on the p
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12. Effect of third strand composition on the triple helix formation: purine versus pyrimidine oligodeoxynucleotides.
Exon 5 of the human aprt gene contains an oligo-purine-oligopyrimidine stretch of 17 bp (5'-CCCTCTTCTCTCTCCT-3') within the coding region. (T,C)-, (G,T)- and (G,A)-containing oligonucleotides were compared for their ability to form stable triple helices with their DNA target. (G,T) oligodeoxynucleotides, whether parallel or antiparallel, were unable to bind