62 research outputs found

    Indexação de variedades de videira provenientes do cultivo in vitro visando a micropropagação de material livre do cancro-bacteriano.

    Get PDF
    O cancro-bacteriano causado por Xanthomonas campestris pv. viticola (Xcv) é uma das mais importantes doenças da videira no Vale do São Francisco. Recomenda-se uma combinação de várias medidas para diminuir a severidade da doença, pois ainda não existem métodos eficientes de controle. Uma das principais medidas é a utilização de material propagativo livre do patógeno. Desta forma, o objetivo deste trabalho foi promover a limpeza clonal de mudas de videira por meio da cultura de tecidos, para eliminação de Xcv. Foram utilizadas plantas de videira de variedades copa e porta-enxerto para indexação a partir de fragmentos retirados da região mediana do caule. Esses fragmentos foram colocados em microtubos contendo água esterilizada e macerados. Após a maceração, o material foi dispensado em placas de Petri contendo meio de cultura NYDAM e acondicionado em B.O.D à temperatura de 28 ºC durante 48 e 72 horas. A avaliação foi realizada quanto à presença ou ausência de colônias bacterianas típicas de Xcv. Após a indexação, todo material livre da bactéria foi multiplicado por meio de segmentos nodais. Todas as plantas, de todas as variedades avaliadas, apresentaram indexação negativa. Assim, a cultura de tecidos com posterior indexação pode ser utilizada para a produção de material propagativo sadio

    DISPOSITION OF L-738,167, A POTENT AND LONG-ACTING FIBRINOGEN RECEPTOR ANTAGONIST, IN DOGS Dose-Dependent Pharmacokinetics

    Get PDF
    ABSTRACT: L-738,167 is a potent and long-acting fibrinogen receptor antagonist and may be useful for treatment of chronic thrombotic occlusive disorders. The purposes of this study were to characterize the metabolism and disposition of L-738,167, and to investigate factors affecting its pharmacokinetic behaviors in dogs, one of the animal models used in pharmacological and toxicological studies. In vitro and in vivo experiments indicated that L-738,167 was not metabolized to any appreciable extent in dogs. Biliary excretion was found to be the major route (ϳ75%) of drug elimination

    Structure-Function Studies of DNA Binding Domain of Response Regulator KdpE Reveals Equal Affinity Interactions at DNA Half-Sites

    Get PDF
    Expression of KdpFABC, a K+ pump that restores osmotic balance, is controlled by binding of the response regulator KdpE to a specific DNA sequence (kdpFABCBS) via the winged helix-turn-helix type DNA binding domain (KdpEDBD). Exploration of E. coli KdpEDBD and kdpFABCBS interaction resulted in the identification of two conserved, AT-rich 6 bp direct repeats that form half-sites. Despite binding to these half-sites, KdpEDBD was incapable of promoting gene expression in vivo. Structure-function studies guided by our 2.5 Å X-ray structure of KdpEDBD revealed the importance of residues R193 and R200 in the α-8 DNA recognition helix and T215 in the wing region for DNA binding. Mutation of these residues renders KdpE incapable of inducing expression of the kdpFABC operon. Detailed biophysical analysis of interactions using analytical ultracentrifugation revealed a 2∶1 stoichiometry of protein to DNA with dissociation constants of 200±100 and 350±100 nM at half-sites. Inactivation of one half-site does not influence binding at the other, indicating that KdpEDBD binds independently to the half-sites with approximately equal affinity and no discernable cooperativity. To our knowledge, these data are the first to describe in quantitative terms the binding at half-sites under equilibrium conditions for a member of the ubiquitous OmpR/PhoB family of proteins

    Modellierung und Berechnung turbulenter Strömungen und Anwendungen in der Technik

    No full text
      &nbsp

    Characterization of the chi psi subcomplex of Pseudomonas aeruginosa DNA polymerase III

    Get PDF
    DNA polymerase III, the main enzyme responsible for bacterial DNA replication, is composed of three sub-assemblies: the polymerase core, the β-sliding clamp, and the clamp loader. During replication, single-stranded DNA-binding protein (SSB) coats and protects single-stranded DNA (ssDNA) and also interacts with the χψ heterodimer, a sub-complex of the clamp loader. Whereas the χ subunits of Escherichia coli and Pseudomonas aeruginosa are about 40% homologous, P. aeruginosa ψ is twice as large as its E. coli counterpart, and contains additional sequences. It was shown that P. aeruginosa χψ together with SSB increases the activity of its cognate clamp loader 25-fold at low salt. The E. coli clamp loader, however, is insensitive to the addition of its cognate χψ under similar conditions. In order to find out distinguishing properties within P. aeruginosa χψ which account for this higher stimulatory effect, we characterized P. aeruginosa χψ by a detailed structural and functional comparison with its E. coli counterpart.Using small-angle X-ray scattering, analytical ultracentrifugation, and homology-based modeling, we found the N-terminus of P. aeruginosa ψ to be unstructured. Under high salt conditions, the affinity of the χψ complexes from both organisms to their cognate SSB was similar. Under low salt conditions, P. aeruginosa χψ, contrary to E. coli χψ, binds to ssDNA via the N-terminus of ψ. Whereas it is also able to bind to double-stranded DNA, the affinity is somewhat reduced.The binding to DNA, otherwise never reported for any other ψ protein, enhances the affinity of P. aeruginosa χψ towards the SSB/ssDNA complex and very likely contributes to the higher stimulatory effect of P. aeruginosa χψ on the clamp loader. We also observed DNA-binding activity for P. putida χψ, making this activity most probably a characteristic of the ψ proteins from the Pseudomonadaceae

    Modellierung und Berechnung turbulenter Strömungen und Anwendungen in der Technik: Teil 2: Formulierung der Randbedingung

    No full text
      &nbsp

    Rohrströmung

    No full text
    corecore