998 resultados para Purification par affinité


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Contém o Alvará porque Vossa Magestade confirma os capítulos e condições da Companhia do Grão Pará e Maranhão, datado de 7 de junho de 1755 e feito por Antonio Joseph Galvão.

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Jean Louis Rodolphe Agassiz foi professor e naturalista suíço naturalizado americano. Nasceu em Motiers, em 28 de maio de 1807, e morreu em Cambridge, em 1873. Estudou em Universidades suíças e alemãs, doutorando-se em Medicina, em Munique, em 1830. Em 1846, fixou-se nos Estados Unidos, onde lecionou em Harvard, e, em 1861, tornou-se cidadão americano. O estudo e a classificação de espécies de peixes brasileiros despertou-lhe o interesse pelo Brasil e , em 1865, chegou ao País à frente de uma expedição científica, que ficou conhecida como Thayer Expedition, custeada pelo milionário americano Nathanael Thayer e patrocinada pelo Imperador D. Pedro II. Permaneceu no País por quinze meses, explorando o Rio Amazonas e o interior cearense, período em que classificou 1.800 espécies da fauna ictiológica. Dessa viagem, resultou o livro A journey in Brasil. Seus estudos de Zoologia e Paleontologia, assim como os dos glaciares da Europa e da América, tornaram-se célebre. A obra científica de Agassiz é constituída por mais de quatrocentos volumes.

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Nota de conteúdo : V.1. Memoire en reponse aux allegations de la France, accompagne de quelques cartes -- V. 2-3. Documents accompagnes de notes explicatives ou rectificatives, 1. ptie, 1536-1713 ; 2. ptie, 1713-1896 -- V. 4. Texte original de documents traduits dans les tomes 2 et 3 -- V. 5. Album : fac-simile de quelques documents reproduits aux tomes 2, 3 et 4 -- V. 6. Atlas : contenant 86 cartes.

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"O livro de João Lúcio de Azevedo continua sendo indispensável ao conhecimento da ocupação da Amazônia, fundada na atividade das missões, como a estrutura de produção das especiarias. Plantadas ao longo dos rios e escoradas na economia coletora florestal e no trabalho do indígena, a missão religiosa é a base do povoamento ali."

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Dicistroviridae is a new family of small, nonenveloped, and +ssRNA viruses pathogenic to both beneficial arthropods and insect pests as well. Triatoma virus (TrV), a dicistrovirus, is a pathogen of Triatoma infestans (Hemiptera: Reduviidae), one of the main vectors of Chagas disease. In this work, we report a single-step method to identify TrV, a dicistrovirus, isolated from fecal samples of triatomines. The identification method proved to be quite sensitive, even without the extraction and purification of RNA virus.

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280 p. : il.

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The author has constructed a synthetic gene for ∝-lytic protease. Since the DNA sequence of the protein is not known, the gene was designed by using the reverse translation of ∝-lytic protease's amino acid sequence. Unique restriction sites are carefully sought in the degenerate DNA sequence to aid in future mutagenesis studies. The unique restriction sites are designed approximately 50 base pairs apart and their appropriate codons used in the DNA sequence. The codons used to construct the DNA sequence of ∝-lytic protease are preferred codons in E-coli or used in the production of β-lactamase. Codon usage is also distributed evenly to ensure that one particular codon is not heavily used. The gene is essentially constructed from the outside in. The gene is built in a stepwise fashion using plasmids as the vehicles for the ∝-lytic oligomers. The use of plasmids allows the replication and isolation of large quantities of the intermediates during gene synthesis. The ∝-lytic DNA is a double-stranded oligomer that has sufficient overhang and sticky ends to anneal correctly in the vector. After six steps of incorporating ∝-lytic DNA, the gene is completed and sequenced to ensure that the correct DNA sequence is present and that no mutations occurred in the structural gene.

β-lactamase is the other serine hydrolase studied in this thesis. The author used the class A RTEM-1 β- lactamase encoded on the plasmid pBR322 to investigate the roll of the conserved threonine residue at position 71. Cassette mutagenesis was previously used to generate all possible amino acid substitutions at position 71. The work presented here describes the purification and kinetic characterization of a T71H mutant previously constructed by S. Schultz. The mutated gene was transferred into plasmid pJN for expression and induced with IPTG. The enzyme is purified by column chromatography and FPLC to homogeneity. Kinetic studies reveal that the mutant has lower k_(cat) values on benzylpenicillin, cephalothin and 6-aminopenicillanic acid but no changes in k_m except for cephalothin which is approximately 4 times higher. The mutant did not change siginificantly in its pH profile compared to the wild-type enzyme. Also, the mutant is more sensitive to thermal denaturation as compared to the wild-type enzyme. However, experimental evidence indicates that the probable generation of a positive charge at position 71 thermally stabilized the mutant.