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Transcrição de genes responsáveis pela síntese de RNA ribossômico em Bacillus subtilis; Transcription genes responsible for the synthesis of ribosomal RNA in Bacillus subtilisNucleic acids, Ribosomal RNA, Genes transcription

Zingales, Bianca Silvana
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 06/06/1975 PT
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O estudo sobre a cinética de incorporação de uridina em ácidos nucleicos permitiu estabelecer que o tamanho do "pool" de precursores permanece constante na presença de concentrações de uridina exógena acima de aproximadamente1 µM. Concluiu-se ainda que todo o sistema de tomada de uridina, medido pela sua incorporação em ácidos nucleicos, apresenta um Km de 5,1 µM e opera a uma velocidade máxima de 11 pmoles/min/l,3 x 107 células. Um estudo análogo, em presença de rifampicina, possibilitou calcular que a meia vida de RNAs mensa - geiros em B. subtilis é de 2 minutos e que 44% da radiatividade incorporada em RNA num determinado instante se encontra na fração de RNA estável (ribossômico e de transferência). A análise do mecanismo de transcrição dos genes para RNA ribossômico foi abordada por meio do estudo do alongamento de cadeias de rRNA já iniciadas, em presença de rifampicina. As relações iniciais de radiatividade incorporada em rRNA 16S e 23S, quando rifampicina e uridina tritiada são adicionadas concomitantemente, bem corno a cinética de decaimento de marcação presente em ambas as espécies de rRNA sugerem que os genes para RNA ribossômico 16S e 23S são cotranscritos nessa ordem, em B. subtilis. Levando-se em consideração essas e outras evidências...

Invited review Giardia duodenalis: Inter-strain variability of proteins, antigens, proteases, isoenzymes and nucleic acids

Guimarães, Semiramis; Sogayar, Maria Inês Lerne; Franco, Marcello F. de
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 45-58
ENG
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Giardia duodenalis isolates from asymptomatic or symptomatic patients and from animals present similarities and differences in the protein composition, antigenic profile, pattern of proteases and isoenzymes, as well as in nucleic acids analysis. In the present overview, these differences and similarities are reviewed with emphasis in the host-parasite interplay and possible mechanisms of virulence of the protozoon.

Microbial nucleic acids employed in diagnostics, sequencing and phylogenetics are subject to detrimental inhibitors and mutagens

Paterson, R. R. M.; Lima, Nelson
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em 28/11/2009 ENG
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Sequencing the genomes of microbial species has increased tremendously. Nucleic acids (NA) are used also for diagnostic and phylogenetic analyses of microbes. It is essential that protocols ensure representative NA. The effect of the "spent" growth medium on NA has not been considered. Surprisingly, fungi are grown on media that support inhibitors and mutagens when producing NA for these purposes1,2,3. This situation is illogical as these secondary metabolites may affect the structure of NA2 and/or inhibit PCR polymerases used in PCR3. The objective of the work was to highlight how NA analyses could be affected by self produced mutagens and inhibitors. Hence, (a) PCR of the idh gene of patulin production in fungi (e.g. Penicillium expansum) and (b) interpretation of the scientific literature were employed to determine the seriousness of the situation. Analysis of idh was successful for culture dependant PCR (CDP) and culture independent PCR (CIP). A reversible inhibition was observed in CDP presumably from inhibitors in cultures. Inhibition was observed in CIP. In some cases, taxa which were predicted to be positive for idh were not, and vice versa. A logical interpretation of this was that the gene was mutated by cultural components. In addition...

Giardia duodenalis: INTER-STRAIN VARIABILITY OF PROTEINS, ANTIGENS, PROTEASES, ISOENZYMES AND NUCLEIC ACIDS

GUIMARÃES,Semiramis; SOGAYAR,Maria Inês Leme; FRANCO,Marcello F. de
Fonte: Instituto de Medicina Tropical Publicador: Instituto de Medicina Tropical
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/1999 EN
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Giardia duodenalis isolates from asymptomatic or symptomatic patients and from animals present similarities and differences in the protein composition, antigenic profile, pattern of proteases and isoenzymes, as well as in nucleic acids analysis. In the present overview, these differences and similarities are reviewed with emphasis in the host-parasite interplay and possible mechanisms of virulence of the protozoon.

Eurytrema coelomaticum: influence of the infection on the reproduction and nucleic acids contents in the albumen gland and ovotestis of Bradybaena similaris

Pinheiro,Jairo; Amato,Suzana B.
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/1995 EN
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The number of eggs laid per snail in Bradybaena similaris and the nucleic acids (DNA and RNA) in the albumen gland and ovotestis were quantified in snails infected with sporocysts of the digenetic trematode Eurytrema coelomaticum. The total number of eggs laid per mollusc was reduced by 96.32% at the end of the larval development. The DNA concentration increased by 700% and the RNA concentration was reduced by 8,38% by the time when the daughter sporocysts of E. coelomaticum were released from B. similaris. The relation between these values and the inhibition of the reproduction observed in infected molluscs is discussed.

Stable carbon isotope analysis of nucleic acids to trace sources of dissolved substrates used by estuarine bacteria.

Coffin, R B; Velinsky, D J; Devereux, R; Price, W A; Cifuentes, L A
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1990 EN
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The natural abundance of stable carbon isotopes measured in bacterial nucleic acids extracted from estuarine bacterial concentrates was used to trace sources of organic matter for bacteria in aquatic environments. The stable carbon isotope ratios of Pseudomonas aeruginosa and nucleic acids extracted from cultures resembled those of the carbon source on which bacteria were grown. The carbon isotope discrimination between the substrate and total cell carbon from bacterial cultures averaged 2.3% +/- 0.6% (n = 13). Furthermore, the isotope discrimination between the substrate and nucleic acids extracted from bacterial cultures was 2.4% +/- 0.4% (n = 10), not significantly different from the discrimination between bacteria and the substrate. Estuarine water samples were prefiltered through 1-micron-pore-size cartridge filters. Bacterium-sized particles in the filtrates were concentrated with tangential-flow filtration and centrifugation, and nucleic acids were then extracted from these concentrates. Hybridization with 16S rRNA probes showed that approximately 90% of the nucleic acids extracted on two sample dates were of eubacterial origin. Bacteria and nucleic acids from incubation experiments using estuarine water samples enriched with dissolved organic matter from Spartina alterniflora and Cyclotella caspia had stable carbon isotope values similar to those of the substrate sources. In a survey that compared diverse estuarine environments...

Condensation of nucleic acids by intercalating aromatic cations.

Kapuscinski, J; Darzynkiewicz, Z
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1984 EN
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Certain intercalating aromatic cations, such as the fluorochrome acridine orange or the antitumor drug Mitoxantrone, induce condensation of nucleic acids in solutions. The appearance of the condensed form during titration of nucleic acids with these intercalating ligands can be quantitatively monitored by light scatter measurements. The resulting highly reproducible light scatter transition curves are typical of the cooperative processes, and the transitions occur at different critical concentrations of the ligands depending upon both the ligand itself and the primary structure (base and sugar composition) and the secondary structure (single- or double-stranded) of the nucleic acids. The mechanism of condensation of nucleic acids by intercalating cationic ligands is discussed in light of the model of interactions occurring between certain intercalators and single-stranded nucleic acids and compared with the condensation induced by polyvalent "simple" cations such as Co3+ or spermine4+. The described phenomenon can have an application in analytical and preparative biochemistry for characterization of the primary and secondary structure of nucleic acids and for separation of the compounds. The possibility that the condensation plays a role in mutagenic and pharmacological effects of aromatic cations is considered.

The use of sodium perchlorate in deproteinization during the preparation of nucleic acids (Short Communication)

Wilcockson, John
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/1973 EN
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Sodium perchlorate in high concentrations will remove from solution the detergent sodium dodecyl sulphate and protein complexed with it. This and the failure of proteins to be precipitated by ethanol from solutions containing a high concentration of sodium perchlorate can be utilized as efficient, rapid and simple deproteinization procedures during the preparation of nucleic acids.

A direct effect of growth hormone on the incorporation of precursors into proteins and nucleic acids of perfused rat liver

Jefferson, L. S.; Korner, A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /09/1967 EN
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1. The livers of rats were perfused in situ. When the amino acid concentration in the perfusing medium was that present in rat plasma, the addition of growth hormone to the medium stimulated the incorporation of labelled amino acids into liver protein only marginally and not to a statistically significant extent. When, however, the amino acid concentration was raised to three times that present in rat plasma, growth hormone significantly and substantially stimulated amino acid incorporation into protein within 30min. of perfusion of normal rat liver. 2. A significant effect of growth hormone on labelling of normal rat-liver protein was seen with concentrations not much greater than those reported to be present in rat plasma. 3. The labelling of nucleic acids of normal and hypophysectomized rat liver by [3H]orotic acid was enhanced by addition of growth hormone to the perfusing medium when normal concentrations of amino acids were used. 4. At elevated concentrations of amino acids, growth hormone stimulated labelling of nucleic acids of hypophysectomized rat liver at 30 and 60min. of perfusion. Under these conditions, nucleic acids of normal rats were labelled to about the same extent in control and hormone-treated livers at 30min. and...

The Effect of Dye-Dye Interactions on the Spatial Resolution of Single-Molecule FRET Measurements in Nucleic Acids

Di Fiori, Nicolas; Meller, Amit
Fonte: The Biophysical Society Publicador: The Biophysical Society
Tipo: Artigo de Revista Científica
Publicado em 19/05/2010 EN
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We study the effect of dye-dye interactions in labeled double-stranded DNA molecules on the Förster resonance energy transfer (FRET) efficiency at the single-molecule level. An extensive analysis of internally labeled double-stranded DNA molecules in bulk and at the single-molecule level reveals that donor-acceptor absolute distances can be reliably extracted down to ∼3-nm separation, provided that dye-dye quenching is accounted for. At these short separations, we find significant long-lived fluorescence fluctuations among discrete levels originating from the simultaneous and synchronous quenching of both dyes. By comparing four different donor-acceptor dye pairs (TMR-ATTO647N, Cy3-ATTO647N, TMR-Cy5, and Cy3-Cy5), we find that this phenomenon depends on the nature of the dye pair used, with the cyanine pair Cy3-Cy5 showing the least amount of fluctuations. The significance of these results is twofold: First, they illustrate that when dye-dye quenching is accounted for, single-molecule FRET can be used to accurately measure inter-dye distances, even at short separations. Second, these results are useful when deciding which dye pairs to use for nucleic acids analyses using FRET.

Structure-Based Simulations of the Translocation Mechanism of the Hepatitis C Virus NS3 Helicase along Single-Stranded Nucleic Acid

Zheng, Wenjun; Tekpinar, Mustafa
Fonte: The Biophysical Society Publicador: The Biophysical Society
Tipo: Artigo de Revista Científica
Publicado em 19/09/2012 EN
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The NS3 helicase of Hepatitis C virus is an ATP-fueled molecular motor that can translocate along single-stranded (ss) nucleic acid, and unwind double-stranded nucleic acids. It makes a promising antiviral target and an important prototype system for helicase research. Despite recent progress, the detailed mechanism of NS3 helicase remains unknown. In this study, we have combined coarse-grained (CG) and atomistic simulations to probe the translocation mechanism of NS3 helicase along ssDNA. At the residue level of detail, our CG simulations have captured functionally important interdomain motions of NS3 helicase and reproduced single-base translocation of NS3 helicase along ssDNA in the 3′–5′ direction, which is in good agreement with experimental data and the inchworm model. By combining the CG simulations with residue-specific perturbations to protein-DNA interactions, we have identified a number of key residues important to the translocation machinery that agree with previous structural and mutational studies. Additionally, our atomistic simulations with targeted molecular dynamics have corroborated the findings of CG simulations and further revealed key protein-DNA hydrogen bonds that break/form during the transitions. This study offers...

Nucleic acids and endosomal pattern recognition: how to tell friend from foe?

Brencicova, Eva; Diebold, Sandra S.
Fonte: Frontiers Media S.A. Publicador: Frontiers Media S.A.
Tipo: Artigo de Revista Científica
Publicado em 30/07/2013 EN
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The innate immune system has evolved endosomal and cytoplasmic receptors for the detection of viral nucleic acids as sensors for virus infection. Some of these pattern recognition receptors (PRR) detect features of viral nucleic acids that are not found in the host such as long stretches of double-stranded RNA (dsRNA) and uncapped single-stranded RNA (ssRNA) in case of Toll-like receptor (TLR) 3 and RIG-I, respectively. In contrast, TLR7/8 and TLR9 are unable to distinguish between viral and self-nucleic acids on the grounds of distinct molecular patterns. The ability of these endosomal TLR to act as PRR for viral nucleic acids seems to rely solely on the mode of access to the endolysosomal compartment in which recognition takes place. The current dogma states that self-nucleic acids do not enter the TLR-sensing compartment under normal physiological conditions. However, it is still poorly understood how dendritic cells (DC) evade activation by self-nucleic acids, in particular with regard to specific DC subsets, which are specialized in taking up material from dying cells for cross-presentation of cell-associated antigens. In this review we discuss the current understanding of how the immune system distinguishes between foreign and self-nucleic acids and point out some of the key aspects that still require further research and clarification.

The 2014 Nucleic Acids Research Database Issue and an updated NAR online Molecular Biology Database Collection

Fernández-Suárez, Xosé M.; Rigden, Daniel J.; Galperin, Michael Y.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
EN
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The 2014 Nucleic Acids Research Database Issue includes descriptions of 58 new molecular biology databases and recent updates to 123 databases previously featured in NAR or other journals. For convenience, the issue is now divided into eight sections that reflect major subject categories. Among the highlights of this issue are six databases of the transcription factor binding sites in various organisms and updates on such popular databases as CAZy, Database of Genomic Variants (DGV), dbGaP, DrugBank, KEGG, miRBase, Pfam, Reactome, SEED, TCDB and UniProt. There is a strong block of structural databases, which includes, among others, the new RNA Bricks database, updates on PDBe, PDBsum, ArchDB, Gene3D, ModBase, Nucleic Acid Database and the recently revived iPfam database. An update on the NCBI’s MMDB describes VAST+, an improved tool for protein structure comparison. Two articles highlight the development of the Structural Classification of Proteins (SCOP) database: one describes SCOPe, which automates assignment of new structures to the existing SCOP hierarchy; the other one describes the first version of SCOP2, with its more flexible approach to classifying protein structures. This issue also includes a collection of articles on bacterial taxonomy and metagenomics...

The 2014 Nucleic Acids Research Database Issue and an updated NAR online Molecular Biology Database Collection

Fernández-Suárez, Xosé M.; Rigden, Daniel J.; Galperin, Michael Y.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
584.6278%
The 2014 Nucleic Acids Research Database Issue includes descriptions of 58 new molecular biology databases and recent updates to 123 databases previously featured in NAR or other journals. For convenience, the issue is now divided into eight sections that reflect major subject categories. Among the highlights of this issue are six databases of the transcription factor binding sites in various organisms and updates on such popular databases as CAZy, Database of Genomic Variants (DGV), dbGaP, DrugBank, KEGG, miRBase, Pfam, Reactome, SEED, TCDB and UniProt. There is a strong block of structural databases, which includes, among others, the new RNA Bricks database, updates on PDBe, PDBsum, ArchDB, Gene3D, ModBase, Nucleic Acid Database and the recently revived iPfam database. An update on the NCBI’s MMDB describes VAST+, an improved tool for protein structure comparison. Two articles highlight the development of the Structural Classification of Proteins (SCOP) database: one describes SCOPe, which automates assignment of new structures to the existing SCOP hierarchy; the other one describes the first version of SCOP2, with its more flexible approach to classifying protein structures. This issue also includes a collection of articles on bacterial taxonomy and metagenomics...

Label-Free Live-Cell Imaging of Nucleic Acids Using Stimulated Raman Scattering Microscopy

Zhang, Xu; Roeffaers, Maarten B. J.; Basu, Srinjan; Daniele, Joseph R.; Fu, Dan; Freudiger, Christian Wilhelm; Holtom, Gary R.; Xie, Xiaoliang Sunney
Fonte: John Wiley and Sons Publicador: John Wiley and Sons
Tipo: Artigo de Revista Científica
EN_US
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688.9798%
Imaging of nucleic acids is important for studying cellular processes such as cell division and apoptosis. A noninvasive label-free technique is attractive. Raman spectroscopy provides rich chemical information based on specific vibrational peaks. However, the signal from spontaneous Raman scattering is weak and long integration times are required, which drastically limits the imaging speed when used for microscopy. Coherent Raman scattering techniques, comprising coherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS) microscopy, overcome this problem by enhancing the signal level by up to five orders of magnitude. CARS microscopy suffers from a nonresonant background signal, which distorts Raman spectra and limits sensitivity. This makes CARS imaging of weak transitions in spectrally congested regions challenging. This is especially the case in the fingerprint region, where nucleic acids show characteristic peaks. The recently developed SRS microscopy is free from these limitations; excitation spectra are identical to those of spontaneous Raman and sensitivity is close to shot-noise limited. Herein we demonstrate the use of SRS imaging in the fingerprint region to map the distribution of nucleic acids in addition to proteins and lipids in single salivary gland cells of Drosophila larvae...

Circulating nucleic acids as a tumor marker

Chan, K.C.A.; Lo, Y.M.D.
Fonte: Murcia : F. Hernández Publicador: Murcia : F. Hernández
Tipo: Artigo de Revista Científica Formato: application/pdf
ENG
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Patients suffering from malignant diseases have been shown to have increased amounts of cell free nucleic acids in their circulation. As genetic and epigenetic alterations are increasingly characterized in different types of tumors, such changes can be used to detect tumor-derived nucleic acids in the circulation. To date, nearly all tumor-associated nucleic acids have been detected in the plasma or serum of cancer patients. Moreover, increased levels of circulating viral nucleic acids have also been demonstrated in patients with certain cancers associated with viral infections. The concentration of these tumor-associated nucleic acid species is generally related to the tumor load and the extent of the disease. Serial monitoring of plasma nucleic acids thus provides a good way to follow disease progress and to predict the outcome of such patients. In this review, different approaches of detecting tumorrelated nucleic acids in the circulation and their potential as tumor markers in the screening, monitoring and prognostication of malignant diseases are discussed.

Polymeric micelles as versatile carriers for drugs and nucleic acids

El Sabahy, Mahmoud
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
EN
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Le cancer est la principale cause de mortalité au Canada. Les taxanes (e.g. le paclitaxel et le docétaxel (DCTX)) constituent des remèdes efficaces contre une série de tumeurs solides telles que les cancers du sein, du poumon et de l’ovaire. Par ailleurs, des acides nucléiques (e.g. les oligonucléotides antisens (AON) ou les petits ARN interférents (siRNAs)), capables de supprimer sélectivement certains oncogènes impliqués dans la carcinogénèse, sont actuellement étudiés pour traiter une large gamme de cancers. Bien que l’activité des taxanes et des acides nucléiques soit bien établie sur des modèles humains et/ou animaux, plusieurs aspects physico-chimiques et cliniques restent encore à améliorer. Leur solubilité limitée (pour les taxanes), leur dégradation rapide dans le sang (pour les acides nucléiques), leur élimination précoce, leur absence de sélectivité et leur toxicité envers les tissus sains sont les principaux facteurs limitant leur efficacité. C’est pourquoi de nombreux efforts ont porté sur l’élaboration de systèmes de vectorisation ciblés à base de polymères, dans le but de surmonter les problèmes associés aux thérapies actuelles. Dans cette thèse, deux types de micelles polymères ont été développés pour la vectorisation de DCTX et d’acides nucléiques. D’une part...

Fractionation of nucleic acids from Penicillium chrysogenum and associated ribonucleic acid viruses by selective exclusion and retention in agarose gels

Petrović, S. L.; Šumonja, B. D.; Vasiljević, R. B.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1974 EN
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Double-stranded nucleic acids from a strain of Penicillium chrysogenum containing RNA viruses were isolated by agarose-gel filtration, and separated into DNA and double-stranded RNA fractions by agarose-gel chromatography in 2.5m-NaCl. The DNA fraction contained less than 1% alkali-labile polynucleotides, and sedimented homogeneously at 8–10S in alkaline sucrose gradients. In CsCl gradients it tended to band in the density region of 1.66–1.72g/ml. It had a `melting' temperature (Tm) of 75°C in 0.015m-NaCl–0.0015m-trisodium citrate, corresponding to 51.5mol% of G+C. The double-stranded RNA fraction did not contain detectable DNA. It could not band in CsCl up to a density of 1.78g/ml, and mainly consisted of a 14–15S RNA species with a Tm of 88.5°C in the above solvent, and a G+C content of 49.3 mol%.

Using Nucleic Acids to Repair β-Globin Gene Mutations

Kierlin-Duncan, Monique Natasha
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação Formato: 17300107 bytes; application/pdf
EN_US
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Nucleic acids are an emerging class of therapeutics with the capacity to repair both DNA and RNA mutations in clinically relevant targets. We have used two approaches, mobile group II introns and Spliceosome Mediated RNA Trans-splicing (SMaRT), to correct β-globin mutations at the DNA and RNA levels respectively. We show that the group II intron inserts site-specifically into its DNA target, even when similar targets are available. Experiments transitioning this therapeutic into mammalian cell systems are then described. We also illustrate how SMaRT RNA repair can be used to correct β-globin mutations involved in sickle cell disease and some forms of β- thalassemia. We uncovered diverse repair efficiencies when targeting sickle cell versus β- thalassemia transcripts in mammalian cells. Possible reasons for this and how it might direct target choice for the SMaRT therapeutic approach are both discussed. The therapeutic molecule in SMaRT, a Pre-Trans-splicing Molecule or PTM, is also delivered via lentivirus to erythrocyte precursors cultured from the peripheral blood of sickle cell patients. Preliminary results from these experiments are discussed.; Dissertation

Characterization of dipyridophenazine complexes of ruthenium( 11): the light switch effect as a function of nucleic acid sequence and conformation

Jenkins, Yonchu; Friedman, Alan; Turro, Nicholas; Barton, Jacqueline
Fonte: The American Chemical Society: Biochemistry Publicador: The American Chemical Society: Biochemistry
Tipo: Abstract Formato: 31371 bytes; application/pdf
EN_US
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Spectroscopic parameters for two novel ruthenium complexes on binding to nucleic acids of varying sequences and conformations have been determined. These complexes, R~(bpy)~dppz~+ and Ru(phen)2dppz2+ (bpy = 2,2’-bipyridine; phen = 1,l0-phenanthroline; dppz = dipyrido[3,2:a-2’,3’:c]- phenazine) serve as “molecular light switches” for DNA, displaying no photoluminescence in aqueous solution but luminescing intensely in the presence of DNA. The luminescent enhancement observed upon binding is attributed to the sensitivity of the excited state to quenching by water; in DNA, the metal complex, upon intercalation into the helix, is protected from the aqueous solvent, thereby preserving the luminescence. Correlations between the extent of protection (depending upon the DNA conformation) and the luminescence parameters are observed. Indeed, the strongest luminescent enhancement is observed for intercalation into DNA conformations which afford the greatest amount of overlap with access from the major groove, such as in triple helices. Differences are observed in the luminescent parameters between the two complexes which also correlate with the level of water protection. In the presence of nucleic acids, both complexes exhibit biexponential decays in emission. Quenching studies are consistent with two intercalative binding modes for the dppz ligand from the major groove: one in which the metal-phenazine axis lies along the DNA dyad axis and another where the metal-phenazine axis lies almost perpendicular to the DNA dyad axis. Ru(bpy)2dppz2+ and Ru(phen)2dppz2+ are shown here to be unique reporters of nucleic acid structures and may become valuable in the design of new diagnostics for DNA.