Self Purification
Mostrando 13-24 de 64 artigos, teses e dissertações.
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13. Níveis e origem da acidificação das chuvas na região do Rio Grande, RS
The current article presents the first data on physical-chemical parameters of wet precipitation collected at single collection point in the city of Rio Grande, during the period of 12 months in 1997-1998. The employed technique of rainwater separation into several portions made clear the process of the atmosphere self-purification during a precipitation eve
Química Nova. Publicado em: 2000-10
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14. The strands of both polarities of a small circular RNA from carnation self-cleave in vitro through alternative double- and single-hammerhead structures.
The sequence of a circular RNA from carnation has been determined and found to consist of 275 nucleotide residues adopting a branched secondary structure of minimum free energy. Both plus and minus strands of this RNA can form the hammerhead structures proposed to mediate the in vitro self-cleavage of a number of small infectious plant RNAs and the transcrip
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15. Alternative hammerhead structures in the self-cleavage of avocado sunblotch viroid RNAs.
The plus and minus RNAs of the 247 nt avocado sunblotch viroid (ASBV) undergo site specific RNA self-cleavage reactions in vitro. As with several other self-cleaving RNAs, we proposed hammerhead secondary structures for the sequence around the site of self-cleavage of both RNAs. We have shown previously that, during transcription of a dimeric plus ASBV RNA,
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16. Chlorophyll Proteins of Photosystem I 1
Data are presented which suggest the existence of a light-harvesting pigment-protein complex which is functionally and structurally associated with photosystem I (PSI) reaction centers. These observations are based on techniques which allow isolation of PSI using minimal concentrations of Triton X-100. Properties of density and self aggregation allowed purif
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17. A self-recombining bacterial artificial chromosome and its application for analysis of herpesvirus pathogenesis
A self-recombining bacterial artificial chromosome (BAC) containing the 142-kb pseudorabies virus genome was constructed such that the viral genome is rapidly excised from the BAC vector backbone on delivery into mammalian cells. The recombination is mediated by loxP sites in the plasmid and Cre recombinase encoded within the BAC vector. A synthetic intron i
The National Academy of Sciences.
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18. The RNA of both polarities of the peach latent mosaic viroid self-cleaves in vitro solely by single hammerhead structures.
Hammerhead self-cleavage of dimeric, monomeric, truncated and mutated transcripts derived from both polarities of the peach latent mosaic viroid (PLMVd) were characterized. In contrast to some results previously published for a very close sequence variant (see ref. 1), these RNAs exhibit a virtually identical self-cleavage during transcription and after puri
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19. Comparative Studies on S-Glycoproteins Purified from Different S-Genotypes in Self-Incompatible BRASSICA Species I. Purification and Chemical Properties
S-glycoproteins, i.e. stigma glycoproteins that are heritable in correlation with S allele in self-incompatible Brassica species, were apparently purified for three S alleles in B. oleracea. From SDS gel electrophoresis, the estimated molecular weight for two of the S-glycoproteins was 57,000. The other S-glycoprotein was considered to be heterogeneous with
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20. The sexual inducer of Volvox carteri: purification, chemical characterization and identification of its gene
The sexual inducer of Volvox carteri f. nagariensis is a glycoprotein and one of the most potent biological effector molecules known. It is synthesized by sperm cells and converts asexually growing males and females to the sexual pathway. Until now, large-scale production of the inducer was made impossible by an inherent biological `switch' mechanism, the sp
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21. Visualizing tertiary folding of RNA and RNA-protein interactions by a tethered iron chelate: analysis ofHIV-1 Tat-TAR complex.
Replication of human immunodeficiency virus type 1 (HIV-1) requires specific interactions of Tat protein with the trans -activation responsive region (TAR) RNA, a 59 base stem-loop structure located at the 5'-end of all HIV transcripts. We have used an intramolecular RNA self-cleaving strategy to determine the folding of TAR RNA and its interactions with a T
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22. Self-catalyzed destruction of cytochrome P-450: covalent binding of ethynyl sterols to prosthetic heme.
The hepatic pigment accumulated as a consequence of the self-catalyzed destruction of cytochrome P-450 by norethisterone (17-hydroxy-19-nor-17 alpha-pregn-4-en-20-yn-3-one), after acidic methylation and purification, consists of two virtually identical, probably isomeric, porphyrins. Radiolabeled norethisterone is incorporated into both porphyrin products. T
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23. Plus and minus RNAs of peach latent mosaic viroid self-cleave in vitro via hammerhead structures.
Peach latent mosaic viroid (PLMVd), the causal agent of peach latent mosaic disease, has been sequenced and found to be a circular RNA molecule of 337 nucleotide residues, which adopts a branched conformation when it is folded in the model of lowest free energy. PLMVd exhibits limited homologies with other viroids and some satellite RNAs, but it does not hav
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24. Normal and leukemic hematopoiesis: Are leukemias a stem cell disorder or a reacquisition of stem cell characteristics?
Leukemia can be viewed as a newly formed, abnormal hematopoietic tissue initiated by a few leukemic stem cells (LSCs) that undergo an aberrant and poorly regulated process of organogenesis analogous to that of normal hematopoietic stem cells. A hallmark of all cancers is the capacity for unlimited self-renewal, which is also a defining characteristic of norm
National Academy of Sciences.