Ecdysterone
Mostrando 1-12 de 19 artigos, teses e dissertações.
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1. Hypnotic effect of ecdysterone isolated from pfaffia glomerata (spreng.) pedersen / Efeito hipinótico de ecdisterona isolada de Pfaffi a glomerata (Spreng.) Pedersen
Neste trabalho foi avaliado, em roedores, o efeito depressor das frações clorofórmio (CHCl3), acetato de etila (EtOAc) e n-butanol, obtidas das partes subterrâneas de Pfaffi a glomerata, empregando-se o teste de tempo de sono barbitúrico como referência. Somente a fração lipofílica (CHCl3:EtOAc, 1:1, m/m) (i.p. 500 mg/kg; v.o. 1000 mg/kg) potenciou
Publicado em: 2010
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2. Localization of ecdysterone on polytene chromosomes of Drosophila melanogaster.
Ecdysterone has been crosslinked in situ to polytene chromosomes of salivary glands of Drosophila melanogaster by photoactivation. The crosslinked hormone has been localized on the chromosomes by indirect immunofluorescence microscopy. At different developmental stages the hormone was detected at different chromosomal loci. These chromosomal sites correspond
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3. Genes for Drosophila small heat shock proteins are regulated differently by ecdysterone.
Genes for small heat shock proteins (hsp27 to hsp22) are activated in late third-instar larvae of Drosophila melanogaster in the absence of heat stress. This regulation has been simulated in cultured Drosophila cells in which the genes are activated by the addition of ecdysterone. Sequence elements (HERE) involved in ecdysterone regulation of the hsp27 and h
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4. Identification and characterization of the ecdysterone receptor in Drosophila melanogaster by photoaffinity labeling
Salivary glands of third-instar larvae of Drosophila melanogaster as well as Drosophila Kc tissue culture cells have been irradiated in the presence of ecdysterone. Irradiation covalently links ecdysterone to a single cellular protein, which is similar, if not identical, in salivary glands and in Kc cells. This protein has a molecular weight of 130,000 and i
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5. Ecdysterone receptor is a sequence-specific transcription factor involved in the developmental regulation of heat shock genes.
Purification of ecdysterone receptor from Drosophila melanogaster to apparent homogeneity is reported. Purified receptor binds specifically to several sequences in the promoters of the developmentally active hsp27 and hsp23 heat shock genes that were previously implied in ecdysterone regulation of the genes and that share limited homology among themselves an
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6. Ecdysterone regulatory elements function as both transcriptional activators and repressors.
A synthetic, 23-bp ecdysterone regulatory element (EcRE), derived from the upstream region of the Drosophila melanogaster hsp27 gene, was inserted adjacent to the herpes simplex virus thymidine kinase promoter fused to a bacterial gene for chloramphenicol acetyltransferase (CAT). Hybrid constructs were transfected into Drosophila S3 cells and assayed for ecd
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7. Perturbation of chromatin architecture on ecdysterone induction of Drosophila melanogaster small heat shock protein genes.
Alterations in the pattern of DNase I hypersensitivity were observed on ecdysterone-stimulated transcription of Drosophila melanogaster small heat shock protein genes. Perturbations were induced near hsp27 and hsp22, coupled with an extensive domain of chromatin unfolding in the intergenic region between hsp23 and the developmentally regulated gene 1. These
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8. Selective gene expression induced by ecdysterone in cultured fat bodies of Drosophila.
Expression of the LSP-2 and P1 genes was induced in cultured fat bodies of Drosophila third-instar larvae by supplementing the culture medium with ecdysterone. The fat bodies were isolated from ecdysterone-deficient larvae of the temperature-sensitive mutant ecd1, which were shifted from the permissive to the restrictive temperature either at the beginning o
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9. Synthesis of low molecular weight heat shock peptides stimulated by ecdysterone in a cultured Drosophila cell line.
Treatment of Schneider's line 3 Drosophila cells with the steroid hormone ecdysterone rapidly stimulated the synthesis and accumulation of the polypeptide previously designated p7 [Berger, E. M., Ireland, R. C. & Wyss, C. (1980) Somatic Cell Genet. 6, 119-129]. In this report, p7 is identified as the 23,000-dalton heat shock polypeptide (hsp23). In addition
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10. Induction of translatable mRNA for dopa decarboxylase in Drosophila: an early response to ecdysterone.
Ecdysteroid titer and dopa decarboxylase (aromatic-L-amino-acid carboxy-lyase, EC 4.1.1.28) activity were determined throughout the life cycle of Drosophila melanogaster. Five peaks in the amount of hormone were observed, which preceeded five dopa decarboxylase peaks by times ranging from 5 to 58 hr. Late in the third instar the hormone and enzyme maxima are
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11. Sequences involved in temperature and ecdysterone-induced transcription are located in separate regions of a Drosophila melanogaster heat shock gene.
The transcriptional regulation of the Drosophila melanogaster hsp27 (also called hsp28) gene was studied by introducing altered genes into the germ line by P element-mediated transformation. DNA sequences upstream of the gene were defined with respect to their effect on steroid hormone-induced and heat-induced transcription. These two types of control were f
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12. The ovarian, ecdysterone, and heat-shock-responsive promoters of the Drosophila melanogaster hsp27 gene react very differently to perturbations of DNA sequence.
The effect of various types of DNA sequence alterations on the activity of the ovarian, ecdysterone, and heat-shock-responsive promoters of the Drosophila melanogaster hsp27 gene was studied by P element-mediated germ line transformation. Regions of DNA required for proper expression of the gene under these different conditions were identified. Wild-type lev