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Estudo dos factores que interferiram na implementação dos cinco s’s em Portugal, durante 2009 – 2010, nos centros de saúde (Aveiro, Ovar, Vagos) e centro de saúde de Santa Maria - Bragança; hospital são João de Deus – Famalicão; hospital distrital de Chaves – serviço de pediatria; centro hospitalar de Povoa do Varzim/Vila do Conde – unidade de cirurgia do ambulatório; maternidade Júlio Dinis – serviço de ginecologia – porto; hospital Santa Maria Maior – Barcelos

Rocha, Vanda Idalina do Nascimento de Jesus Lopes
Fonte: Universidade de Trás-os-Montes e Alto Douro Publicador: Universidade de Trás-os-Montes e Alto Douro
Tipo: Dissertação de Mestrado
POR
Relevância na Pesquisa
27.19%
Dissertação de Mestrado em Gestão de Serviços de Saúde; Das inúmeras ferramentas que podem ser aplicadas na implementação de um Sistema da Qualidade total numa empresa ou instituição é o projecto dos 5S. Pode-se dizer que este será o ponto de partida e um requisito básico para o controlo da qualidade, dado conferir, aos sectores, vários benefícios. As condições de limpeza, organização, ordem e de autodisciplina são fundamentais para a produtividade. O conceito do Método 5S, deriva das palavras surgirem no Japão, onde cada um destes conceitos começa com a letra “S”, logo o método ser designado por 5S. Contudo, houve adaptação dos conceitos para a língua portuguesa, bem como noutras línguas, cujos países desenvolveram programas semelhantes com o objectivo de melhorar a qualidade. Pretendemos com este estudo identificar que factores interferiram na implementação da metodologia dos 5S, nas instituições de saúde em Portugal. Os dados foram obtidos através de uma entrevista feita aos profissionais responsáveis pelo projecto. Deste estudo conclui-se que esta ferramenta é uma mais-valia para as instituições.; The many tools which may be applied in the implementation of a system of total quality in a company or institution is the project of 5S. May-say that this will be the point of departure and a basic prerequisite for the quality control...

Changes in Bacterioplankton Community Structure and Activity with Depth in a Eutrophic Lake as Revealed by 5S rRNA Analysis

Dominik, Katja; Höfle, Manfred G.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /07/2002 EN
Relevância na Pesquisa
27.19%
The community structure of bacterioplankton was studied at different depths (0 to 25 m) of a temperate eutrophic lake (Lake Plußsee in northern Germany) by using comparative 5S rRNA analysis. The relative amounts of taxonomic groups were estimated from 5S rRNA bands separated by high-resolution electrophoresis. Comparison of partial 5S rRNA sequences enabled detection of changes in single taxa over space and during seasons. Overall, the bacterioplankton community was dominated by 3 to 14 abundant (>4% of the total 5S rRNA) taxa. In general, the number of 5S rRNA bands (i.e., the number of bacterial taxa) decreased with depth. In the fall, when thermal stratification and chemical stratification were much more pronounced than they were in the spring, the correlation between the depth layers and the community structure was more pronounced. Therefore, in the fall each layer had its own community structure; i.e., there were different community structures in the epilimnion, the metalimnion, and the hypolimnion. Only three 5S rRNA bands were detected in the hypolimnion during the fall, and one band accounted for about 70% of the total 5S rRNA. The sequences of individual 5S rRNA bands from the spring and fall were different for all size classes analyzed except two bands...

Both the 5S rRNA gene and the AT-rich flanks of xenopus laevis oocyte-type 5S rDNA repeat are required for histone H1-dependent repression of transcription of pol III-type genes in in vitro reconstituted chromatin.

Tomaszewski, R; Mogielnicka, E; Jerzmanowski, A
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 15/12/1998 EN
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Incorporation of somatic histone H1 into chromatin during embryogenesis of Xenopus laevis results in repression of transcription of the oocyte- but not the somatic-type 5S rRNA genes. We showed earlier that a similar effect of the H1 observed in chromatin reconstituted on circular plasmids in vitro depends on its binding to the AT-rich flanks of the oocyte-type 5S rRNA gene. H1 binding results in stabilization of nucleosomes within the oocyte 5S rDNA repeat comprising the 5S rRNA gene with flanks and in reorganization of chromatin on the entire plasmid DNA. Performing in vitro transcription on reconstituted minichromosome templates carrying the oocyte 5S rRNA gene placed in different arrangements and at different distances from the AT-rich flanks, we now establish that the above effects of H1 observed upon its binding to the AT-rich sequences are absolutely dependent on the presence of the 120 bp oocyte 5S rRNA gene in its native position within the flanks. We also find that with the intact oocyte 5S rDNA repeat, the binding of H1 results in repression of transcription of both pol III- and pol II-type genes and that the transcriptionally inactive chromatin state spreads over a distance of at least a few nucleosomes.

Related 5S RNA transcription factors in Xenopus oocytes and somatic cells.

Pelham, H R; Wormington, W M; Brown, D D
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/1981 EN
Relevância na Pesquisa
27.19%
Xenopus oocytes contain an abundant protein that binds specifically to the center of 5S RNA genes and directs their transcription by RNA polymerase III. This protein also binds to 5S RNA. We show here that transcription of cloned 5S RNA genes in extracts derived from Xenopus tissue culture cells is dependent on the intragenic control region and is inhibited by 5S RNA and by antibodies raised against the previously characterized oocyte transcription factor. Somatic cells contain a protein that is similar to the oocyte factor in charge, affinity for heparin-agarose, and antigenicity but has an apparent molecular mass about 2000 daltons greater than that of the oocyte protein. Our experiments strongly suggest that this larger protein is the transcription factor for 5S RNA genes in somatic cells. The 5S RNA may regulate its own synthesis in somatic cells by binding to this protein, which is present at a low concentration. The presence of two different proteins responsible for 5S RNA synthesis in oocytes and in somatic cells cannot by itself explain the developmental control of oocyte and somatic 5S RNA genes, because somatic cell extracts transcribe both types of gene.

Secondary structure of eukaryotic cytoplasmic 5S ribosomal RNA.

Luehrsen, K R; Fox, G E
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1981 EN
Relevância na Pesquisa
27.19%
A five-helix secondary structural model is proposed for eukaryotic cytoplasmic 5S rRNA. All available sequence data are consistent with this model including those from Chlorella 5S rRNA whose sequence is revised by data included here. Various architectural features of eukaryotic 5S rRNA are summarized in terms of this secondary structural model. It is observed that previous failures to identify universal models for 5S rRNA secondary structure stem from significant differences in architecture between eukaryotic cytoplasmic and eubacterial 5S rRNAs. The usual four-helix model for eubacterial 5S rRNA secondary structure nevertheless does share several structural features with the five-helix model presented here for cytoplasmic 5S rRNA. It is thus likely that these two classes of 5S rRNA are the result of evolutionary divergence rather than convergence.

Oligonucleotide directed mutagenesis of Escherichia coli 5S ribosomal RNA: construction of mutant and structural analysis.

Göringer, H U; Wagner, R; Jacob, W F; Dahlberg, A E; Zwieb, C
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 25/09/1984 EN
Relevância na Pesquisa
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The ribosomal 5S RNA gene from the rrnB operon of E. coli was mutagenised in vitro using a synthetic oligonucleotide hybridised to M13 ssDNA containing that gene. The oligonucleotide corresponded to the 5S RNA sequence positions 34 to 51 and changed the guanosine at position 41 to a cytidine. The DNA containing the desired mutation was identified by dot blot hybridisation and introduced back into the plasmid pKK 3535 which contains the total rrnB operon in pBR 322. Plasmid coded 5S rRNA was selectively labeled with 32p using a modified maxi-cell system, and the replacement of guanosine G41 by cytidine was confirmed by RNA sequencing. The growth of cells containing mutant 5S rRNA was not altered by the base change, and the 5S rRNA was processed and incorporated into 50S ribosomal subunits and 70S ribosomes. The structure of wildtype and mutant 5S rRNA was compared by chemical modification of accessible guanosines with kethoxal and limited enzymatic digestion using RNase T1 and nuclease S1. These results showed that the wildtype and mutant 5S rRNA do not differ significantly in their structure. Furthermore, the formation, interconversion and stability of the two 5S rRNA A- and B-conformers are unchanged.

The relation between polyoma T-antigen and increased 5S RNA synthesis in cell-free extracts from polyoma-infected mouse kidney cell cultures.

Matter, J M; Weil, R
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 11/12/1982 EN
Relevância na Pesquisa
27.19%
In polyoma-infected mouse kidney cell cultures 5S RNA synthesis began to increase around 16 h, i.e. 7-9 h after the onset of polyoma T-antigen synthesis. The rate of polyoma-induced 5S RNA synthesis reached a maximum plateau around 25 h when it was 1.8-2.0 times higher than in mock-infected parallel cultures. Stimulation of 5S RNA synthesis in vivo thus coincided in time with the increase in total cellular RNA and protein. Cell-free extracts (S100) prepared at 15 h from mock-(S100-M) or polyoma-infected (S100-Py) mouse kidney cell cultures were indistinguishable with respect to protein concentration and 5S RNA synthesis, using a cloned somatic Xenopus borealis 5S gene as template. S100-Py extracted 25 h after infection contained 30% more protein and synthesized 1.5-2.0 times more 5S RNA than S100-M. Complete removal of the polyoma T-antigens from S100-Py by 3 cycles of immunoprecipitation with hamster anti-T serum remained without effect on stimulated 5S RNA synthesis. However, a linear relationship between 5S RNA synthesis and protein concentration of S100-M and S100-Py was observed.

A comparison of the solution structures and conformational properties of the somatic and oocyte 5S rRNAs of Xenopus laevis.

Romaniuk, P J; de Stevenson, I L; Ehresmann, C; Romby, P; Ehresmann, B
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 25/03/1988 EN
Relevância na Pesquisa
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The secondary and tertiary structures of Xenopus oocyte and somatic 5S rRNAs were investigated using chemical and enzymatic probes. The accessibility of both RNAs towards single-strand specific nucleases (T1, T2, A and S1) and a helix-specific ribonuclease from cobra venom (RNase V1) was determined. The reactivity of nucleobase N7, N3 and N1 positions towards chemical probes was investigated under native (5 mM MgCl2, 100 mM KCl, 20 degrees C) and semi-denaturing (1 mM EDTA, 20 degrees C) conditions. Ethylnitrosourea was used to identify phosphates not reactive towards alkylation under native conditions. The results obtained confirm the presence of the five helical stems predicted by the consensus secondary structure model of 5S rRNA. The chemical reactivity data indicate that loops C and D are involved in a number of tertiary interactions, and loop E folds into an unusual secondary structure. A comparison of the data obtained for the two types of Xenopus 5S rRNA indicates that the conformations of the oocyte and somatic 5S rRNAs are very similar. However, the data obtained with nucleases under native conditions, and chemical probes under semi-denaturing conditions, reveal that helices III and IV in the somatic 5S rRNA are less stable than the same structures in oocyte 5S rRNA. Using chimeric 5S rRNAs...

Differential binding of zinc fingers from Xenopus TFIIIA and p43 to 5S RNA and the 5S RNA gene.

Darby, M K; Joho, K E
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1992 EN
Relevância na Pesquisa
27.22%
Zinc fingers are usually associated with proteins that interact with DNA. Yet in two oocyte-specific Xenopus proteins, TFIIA and p43, zinc fingers are used to bind 5S RNA. One of these, TFIIIA, also binds the 5S RNA gene. Both proteins have nine zinc fingers that are nearly identical with respect to size and spacing. We have determined the relative affinities of groups of zinc fingers from TFIIIA for both 5S RNA and the 5S RNA gene. We have also determined the relative affinities of groups of zinc fingers from p43 for 5S RNA. The primary protein regions for RNA and DNA interaction in TFIIIA are located at opposite ends of the molecule. All zinc fingers from TFIIIA participate in binding 5S RNA, but zinc fingers from the C terminus have the highest affinity. N-terminal zinc fingers are essential for binding the 5S RNA gene. In contrast, zinc fingers at the amino terminus of p43 are essential for binding 5S RNA.

Transcriptionally inactive oocyte-type 5S RNA genes of Xenopus laevis are complexed with TFIIIA in vitro.

Peck, L J; Millstein, L; Eversole-Cire, P; Gottesfeld, J M; Varshavsky, A
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1987 EN
Relevância na Pesquisa
27.22%
An extract from whole oocytes of Xenopus laevis was shown to transcribe somatic-type 5S RNA genes approximately 100-fold more efficiently than oocyte-type 5S RNA genes. This preference was at least 10-fold greater than the preference seen upon microinjection of 5S RNA genes into oocyte nuclei or upon in vitro transcription in an oocyte nuclear extract. The approximately 100-fold transcriptional bias in favor of the somatic-type 5S RNA genes observed in vitro in the whole oocyte extract was similar to the transcriptional bias observed in developing Xenopus embryos. We also showed that in the whole oocyte extract, a promoter-binding protein required for 5S RNA gene transcription, TFIIIA, was bound both to the actively transcribed somatic-type 5S RNA gene and to the largely inactive oocyte-type 5S RNA genes. These findings suggest that the mechanism for the differential expression of 5S RNA genes during Xenopus development does not involve differential binding of TFIIIA to 5S RNA genes.

Identification and chromosomal distribution of 5S rRNA genes in Neurospora crassa.

Metzenberg, R L; Stevens, J N; Selker, E U; Morzycka-Wroblewska, E
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1985 EN
Relevância na Pesquisa
27.22%
The 5S rRNA genes of Neurospora crassa, unlike those of most organisms, are not tandemly arranged, and they are found imbedded in a variety of unique sequences. The 5S rRNA regions of most of the genes are of one type, alpha; however, several other "isotypes" (beta, gamma, delta, zeta, and eta) are also found. We asked whether Neurospora 5S rRNA genes are dispersed on a chromosomal scale and whether genes of different isotypes are spatially segregated. We identified, by DNA sequencing, 5S rRNA genes in 22 5S DNA clones, and we mapped these genes by conventional crosses by using restriction fragment length polymorphisms in their flanking sequences as genetic markers. The results show that the 5S rRNA genes are distributed on at least six of the seven chromosomes. Their location does not appear to be completely random. Some of them are closely linked. One of the chromosomes carries a disproportionate number of 5S rRNA genes of the most common structural type, alpha; another chromosome carries three of the four mapped beta 5S rRNA genes. None of the 5S rRNA genes studied maps close to the nucleolus organizer, the site of the genes that code for the three larger rRNAs.

Bipartite Structure of the 5s Ribosomal Gene Family in a Drosophila Melanogaster Strain, and Its Evolutionary Implications

Samson, M. L.; Wegnez, M.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1988 EN
Relevância na Pesquisa
27.22%
Knowledge of multigenic family organization should provide insight into their mode of evolution. Accordingly, we characterized the 5S ribosomal gene family in the Drosophila melanogaster strain ry(506). The 5S genes in this strain display a striking HindIII restriction difference compared to the ``standard' D. melanogaster 5S genes. The sequence of three ry(506) 5S genes was determined. We show that the HindIII restriction site heterogeneity within the ry(506) 5S family most probably results from the same point mutation, suggesting that a single 5S variant was propagated into the 5S cluster of this strain. Furthermore, we demonstrate that the structural organization of the 5S genes in ry(506) is a bipartite structure, i.e., that about 40% of the 5S genes constitute a HindIII(+)/HindIII(-) mixed cluster, while those remaining constitute an homogeneous HindIII(-) cluster. The events which might lead to such an heterogeneous pattern are discussed from an evolutionary point of view.

Cassandra retrotransposons carry independently transcribed 5S RNA

Kalendar, Ruslan; Tanskanen, Jaakko; Chang, Wei; Antonius, Kristiina; Sela, Hanan; Peleg, Ofer; Schulman, Alan H.
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.22%
We report a group of TRIMs (terminal-repeat retrotransposons in miniature), which are small nonautonomous retrotransposons. These elements, named Cassandra, universally carry conserved 5S RNA sequences and associated RNA polymerase (pol) III promoters and terminators in their long terminal repeats (LTRs). They were found in all vascular plants investigated. Uniquely for LTR retrotransposons, Cassandra produces noncapped, polyadenylated transcripts from the 5S pol III promoter. Capped, read-through transcripts containing Cassandra sequences can also be detected in RNA and in EST databases. The predicted Cassandra RNA 5S secondary structures resemble those for cellular 5S rRNA, with high information content specifically in the pol III promoter region. Genic integration sites are common for Cassandra, an unusual feature for abundant retrotransposons. The 5S in each LTR produces a tandem 5S arrangement with an inter-5S spacing resembling that of cellular 5S. The distribution of 5S genes is very variable in flowering plants and may be partially explained by Cassandra activity. Cassandra thus appears both to have adapted a ubiquitous cellular gene for ribosomal RNA for use as a promoter and to parasitize an as-yet-unidentified group of retrotransposons for the proteins needed in its lifecycle.

Identification and absolute configuration of dihydroxy-arachidonic acids formed by oxygenation of 5S-HETE by native and aspirin-acetylated COX-2

Mulugeta, Surafel; Suzuki, Takashi; Hernandez, Noemi Tejera; Griesser, Markus; Boeglin, William E.; Schneider, Claus
Fonte: The American Society for Biochemistry and Molecular Biology Publicador: The American Society for Biochemistry and Molecular Biology
Tipo: Artigo de Revista Científica
Publicado em /03/2010 EN
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27.22%
Biosynthesis of the prostaglandin endoperoxide by the cyclooxygenase (COX) enzymes is accompanied by formation of a small amount of 11R-hydroxyeicosatetraenoic acid (HETE), 15R-HETE, and 15S-HETE as by-products. Acetylation of COX-2 by aspirin abrogates prostaglandin synthesis and triggers formation of 15R-HETE as the sole product of oxygenation of arachidonic acid. Here, we investigated the formation of by-products of the transformation of 5S-HETE by native COX-2 and by aspirin-acetylated COX-2 using HPLC-ultraviolet, GC-MS, and LC-MS analysis. 5S,15S- dihydroxy (di)HETE, 5S,15R-diHETE, and 5S,11R-diHETE were identified as by-products of native COX-2, in addition to the previously described di-endoperoxide (5S,15S-dihydroxy-9S,11R,8S,12S-diperoxy-6E,13E-eicosadienoic acid) as the major oxygenation product. 5S,15R-diHETE was the only product formed by aspirin-acetylated COX-2. Both 5,15-diHETE and 5,11-diHETE were detected in CT26 mouse colon carcinoma cells as well as in lipopolysaccharide-activated RAW264.7 cells incubated with 5S-HETE, and their formation was attenuated in the presence of the COX-2 specific inhibitor, NS-398. Aspirin-treated CT26 cells gave 5,15-diHETE as the most prominent product formed from 5S-HETE. 5S,15S-diHETE has been described as a product of the cross-over of 5-lipoxygenase (5-LOX) and 15-LOX activities in elicited rat mononuclear cells and human leukocytes...

Abundant 5S rRNA-Like Transcripts Encoded by the Mitochondrial Genome in Amoebozoa ▿ †

Bullerwell, Charles E.; Burger, Gertraud; Gott, Jonatha M.; Kourennaia, Olga; Schnare, Murray N.; Gray, Michael W.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /05/2010 EN
Relevância na Pesquisa
27.22%
5S rRNAs are ubiquitous components of prokaryotic, chloroplast, and eukaryotic cytosolic ribosomes but are apparently absent from mitochondrial ribosomes (mitoribosomes) of many eukaryotic groups including animals and fungi. Nevertheless, a clearly identifiable, mitochondrion-encoded 5S rRNA is present in Acanthamoeba castellanii, a member of Amoebozoa. During a search for additional mitochondrial 5S rRNAs, we detected small abundant RNAs in other members of Amoebozoa, namely, in the lobose amoeba Hartmannella vermiformis and in the myxomycete slime mold Physarum polycephalum. These RNAs are encoded by mitochondrial DNA (mtDNA), cosediment with mitoribosomes in glycerol gradients, and can be folded into a secondary structure similar to that of bona fide 5S rRNAs. Further, in the mtDNA of another slime mold, Didymium nigripes, we identified a region that in sequence, potential secondary structure, and genomic location is similar to the corresponding region encoding the Physarum small RNA. A mtDNA-encoded small RNA previously identified in Dictyostelium discoideum is here shown to share several characteristics with known 5S rRNAs. Again, we detected genes encoding potential homologs of this RNA in the mtDNA of three other species of the genus Dictyostelium as well as in a related genus...

Variability of the 5S and 45S rDNA Sites in Passiflora L. Species with Distinct Base Chromosome Numbers

DE MELO, NATONIEL FRANKLIN; GUERRA, MARCELO
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Publicado em /08/2003 EN
Relevância na Pesquisa
27.22%
Cytologically, the species of Passiflora with known chromosome number can be divided into four groups: (1) 2n = 12, 24, 36; (2) 2n = 24; (3) 2n = 18, 72; and (4) 2n = 20. The base chromosome number proposed for the genus is x = 6, with x = 9, x = 10 and x = 12 being considered secondary base numbers. In the present study, variability of 5S and 45S rDNA sites was investigated in 20 species of these four groups to check the reliability of this hypothesis. In the group with x = 6, five diploid species (2n = 12) exhibit two 5S rDNA sites and two (P. capsularis, P. morifolia and P. rubra) or four (P. misera 2x and P. tricuspis) 45S rDNA sites. The hexaploid cytotype of P. misera had 12 45S rDNA sites and six 5S rDNA. A tetraploid species, P. suberosa, had ten 45S rDNA sites and four 5S rDNA sites, both in the same chromosomes as the 45S rDNA sites. In the group with x = 9, P. actinia, P. amethystina, P. edmundoi, P. elegans, P. galbana, P. glandulosa and P. mucronata displayed six 45S rDNA sites, whereas P. alata, P. cincinnata, P. edulis f. flavicarpa, P. edulis var. roxo and P. laurifolia had four sites. In this group, all species were diploid (2n = 18) and had only two 5S rDNA sites. Passiflora foetida, the only species with 2n = 20...

Implementação da metodologia LEAN “5S's” num posto de trabalho numa empresa metalomecânica

Gomes, Félix Mendes
Fonte: Instituto Politécnico de Viseu. Escola Superior de Tecnologia e Gestão de Viseu Publicador: Instituto Politécnico de Viseu. Escola Superior de Tecnologia e Gestão de Viseu
Tipo: Dissertação de Mestrado
Publicado em /07/2012 POR
Relevância na Pesquisa
27.22%
Mestrado em Engenharia Mecanica e Gestão Industrial; A metodologia “Lean e seis sigma” afirma-se no mundo da indústria como uma poderosa ferramenta de melhoria de processos com uso de indicadores quantitativos inserida numa estratégia disciplinada. Como principal objectivo, em comum com outras ferramentas, tem a redução de custos com forte impacto na diminuição de defeitos, aumento da qualidade dos produtos ou serviços, melhorando a eficiência da organização, por meio da optimização de processos e, consequentemente, o aumento da satisfação dos colaboradores e clientes. É objectivo deste trabalho, o uso dos conceitos fundamentais associados à metodologia Lean, através da aplicação da ferramenta 5S no local de trabalho num processo de produção de uma indústria metalomecânica. A avaliação inicial, baseada numa check list desenvolvida para o efeito, teve como resultado quantitativo o valor de 7,7%, bem como a proposta de acções de melhorias apenas nos 3 primeiros patamares. A segunda auditoria, feita após a implementação das acções de melhoria propostas anteriormente, teve resultados bastantes positivos alcançando uma pontuação de 65,4%. Embora o objectivo dos 75% inicialmente proposto não tenha sido alcançado...

A 5S rRNA/L5 complex is a precursor to ribosome assembly in mammalian cells

Fonte: The Rockefeller University Press Publicador: The Rockefeller University Press
Tipo: Artigo de Revista Científica
Publicado em 01/03/1988 EN
Relevância na Pesquisa
27.22%
A novel 5S RNA-protein (RNP) complex in human and mouse cells has been analyzed using patient autoantibodies. The RNP is small (approximately 7S) and contains most of the nonribosome-associated 5S RNA molecules in HeLa cells. The 5S RNA in the particle is matured at its 3' end, consistent with the results of in vivo pulse-chase experiments which indicate that this RNP represents a later step in 5S biogenesis than a previously described 5S*/La protein complex. The protein moiety of the 5S RNP has been identified as ribosomal protein L5, which is known to be released from ribosomes in a complex with 5S after various treatments of the 60S subunit. Indirect immunofluorescence indicates that the L5/5S complex is concentrated in the nucleolus. L5 may therefore play a role in delivering 5S rRNA to the nucleolus for assembly into ribosomes.

Defining the binding site of Xenopus transcription factor IIIA on 5S RNA using truncated and chimeric 5S RNA molecules.

Romaniuk, P J; de Stevenson, I L; Wong, H H
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 25/03/1987 EN
Relevância na Pesquisa
27.22%
The interaction of TFIIIA with deletion fragments of Xenopus 5S RNA has been quantified using a nitrocellulose filter binding assay. TFIIIA binding was found to be more sensitive to the deletion of nucleotides from the 5' terminus of the 5S RNA as opposed to the 3' terminus. These effects have been correlated to the changes in RNA secondary structure resulting from the deletions. Nucleotides 11-108 of the intact 5S RNA provide the necessary sequence and conformational information required for the binding of TFIIIA. Synthetic 5S RNA genes have been constructed so that in vitro transcription with T7 RNA polymerase yields mature 5S RNA. The transcription factor has a higher affinity for somatic vs. oocyte 5S RNA, similar to the differential affinity of TFIIIA for the two genes. Binding studies with chimeric 5S RNA molecules indicated that the increased binding strength of somatic 5S RNA is conferred by nucleotide substitutions in the 5' half of the molecule.

Transcriptionally inactive oocyte-type 5S RNA genes of Xenopus laevis are complexed with TFIIIA in vitro

Peck, Lawrence J.; Millstein, Larry; Eversole-Cire, Pamela; Gottesfeld, Joel M.; Varshavsky, Alexander
Fonte: Instituto de Tecnologia da Califórnia Publicador: Instituto de Tecnologia da Califórnia
Tipo: Article; PeerReviewed Formato: application/pdf
Publicado em /10/1987
Relevância na Pesquisa
27.22%
An extract from whole oocytes of Xenopus laevis was shown to transcribe somatic-type 5S RNA genes approximately 100-fold more efficiently than oocyte-type 5S RNA genes. This preference was at least 10-fold greater than the preference seen upon microinjection of 5S RNA genes into oocyte nuclei or upon in vitro transcription in an oocyte nuclear extract. The approximately 100-fold transcriptional bias in favor of the somatic-type 5S RNA genes observed in vitro in the whole oocyte extract was similar to the transcriptional bias observed in developing Xenopus embryos. We also showed that in the whole oocyte extract, a promoter-binding protein required for 5S RNA gene transcription, TFIIIA, was bound both to the actively transcribed somatic-type 5S RNA gene and to the largely inactive oocyte-type 5S RNA genes. These findings suggest that the mechanism for the differential expression of 5S RNA genes during Xenopus development does not involve differential binding of TFIIIA to 5S RNA genes.