Pluteus
Mostrando 1-12 de 13 artigos, teses e dissertações.
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1. Development and reproductive cycle of the sea biscuit Clypeaster subdepressus (Echinodermata: Echinoidea) from São Sebastião, SP / Desenvolvimento e ciclo reprodutivo da bolacha-do-mar Clypeaster subdepressus (Echinodermata: Echinoidea) de São Sebastião, SP
Desenvolvimento e ciclo reprodutivo da bolacha-do-mar Clypeaster subdepressus (Echinodermata: Echinoidea) de São Sebastião, SP Resumo: Este trabalho descreve o desenvolvimento embrionário, larval e juvenil da bolacha-do-mar Clypeaster subdepressus sob microscopia de luz e eletrônica de varredura. Analisamos também o ciclo reprodutivo da espécie a parti
Publicado em: 2008
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2. Molecular cloning of five individual stage- and tissue-specific mRNA sequences from sea urchin pluteus embryos.
Five developmentally regulated sea urchin mRNA sequences which increase in abundance between the blastula and pluteus stages of development were isolated by molecular cloning of cDNA. The regulated sequences all appeared in moderately abundant mRNA molecules of pluteus cells and represented 4% of the clones tested. There were no regulated sequences detected
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3. Modulation of nucleosome structure by histone subtypes in sea urchin embryos.
Switches of the types of histones synthesized and incorporated into chromatin occur during sea urchin embryogenesis. In an attempt to define the possible effects of these variant histones on chromatin structure, I have isolated and characterized nucleosome core particles from Strongylocentrotus purpuratus blastula (nearly 100% early histones) and pluteus (75
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4. Messenger RNA prevalence in sea urchin embryos measured with cloned cDNAs.
mRNA prevalence during sea urchin development was measured by treating cDNA clone colonies with labeled cDNAs transcribed from unfertilized egg and embryo poly(A)-RNAs. The number of cytoplasmic transcripts per embryo complementary to several clones was determined independently by titration with poly(A)-RNA in solution, and the amount of cDNA bound to these
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5. Localization of a family of MRNAS in a single cell type and its precursors in sea urchin embryos.
Spec 1 mRNAs increase 100-fold in abundance per embryo during early sea urchin development. Previous studies indicated an enrichment of this mRNA in ectoderm fractions of gastrulae and plutei. We have determined the precise localization of this mRNA by in situ hybridization techniques. In pluteus larvae, the mRNA is highly restricted to a set of morphologica
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6. Stress to cadmium monitored by metallothionein gene induction in Paracentrotus lividus embryos
We used sea urchin embryos as bioindicators to study the effects of exposure to sublethal cadmium concentrations on the expression of the metallothionein (MT) gene stress marker. For this purpose, the complete complementary deoxyribonucleic acid of the species Paracentrotus lividus (Pl) was cloned and sequenced. Northern blot analysis showed that basal level
Cell Stress Society International.
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7. Methylation of DNA in early development: 5-methyl cytosine content of DNA in sea urchin sperm and embryos
By separating formic acid hydrolysates with high pressure chromatography on an Aminex-10 column, we determined the ratio of 5-methyl cytosine to cytosine and other bases of DNA from sea urchin sperm and nuclei of embryos from early cleavage through pluteus stages. Contrary to several previous reports, we could not find any measurable changes in the methylati
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8. Inducible expression of a cloned heat shock fusion gene in sea urchin embryos.
A fusion gene construct, in which the coding sequence for bacterial chloramphenicol acetyltransferase (CAT; acetyl-CoA: chloramphenicol 3-O-acetyltransferase, EC 2.3.1.28) was placed under the control of the regulatory region of the Drosophila gene encoding the 70-kilodalton heat shock protein [Di Nocera, P.P. & Dawid, I.B. (1983) Proc. Natl. Acad. Sci. USA
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9. Reconstitution of membranes and embryonic development in dissociated blastula cells of the sea urchin by reinsertion of aggregation-promoting membrane proteins extracted with butanol.
Blastula embryos of the sea urchin Paracentrotus lividus, when dissociated into single cells by exposure to Ca2+- and Mg2+-free sea water, reassociate spontaneously to form aggregates capable of development to the final larval form (pluteus). This aggregation is prevented by Fab fragments obtained by immunization with purified membranes from blastula embryos
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10. Structure and developmental expression of a sea urchin fibrillar collagen gene.
We have isolated and characterized cDNA and genomic clones that specify a Paracentrotus lividus procollagen chain. The cDNAs code for 160 uninterrupted Gly-Xaa-Yaa triplets and a 252-amino acid carboxyl propeptide. Analysis of the deduced amino acid sequences indicated that the sea urchin polypeptide exhibits structural features that are characteristic of th
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11. Highly identical cassettes of gene regulatory elements, genomically repetitive and present in RNA.
A region in the first intron of a metallothionein-encoding gene of the sea urchin Strongylocentrotus purpuratus (SpMTA gene) regulates its 5' promoter activity. Within this region is a 290-bp cassette of six sequence motifs that are present in other genes in this species and posited to operate as regulatory elements. The cassette, present at high multiplicit
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12. Characterization of two nonallelic pairs of late histone H2A and H2B genes of the sea urchin: differential regulation in the embryo and tissue-specific expression in the adult.
Two nonallelic pairs of late H2A and H2B genes of the sea urchin Psammechinus miliaris were isolated on two different cosmid clones. The genes of cosmid PmL1 are separated by 11 kilobases of DNA and code for the late H2A-2 and H2B-2 variants. The genes of clone PmL2 are divergently transcribed with 1,060 base pairs of intergenic spacer DNA and code for novel