A utilização do método de Segalen na caracterização dos materiais amorfos de solos ocorrendo em climas temperados e tropicais

O método cinético de dissolução de Segalen é aplicado a argilas de solos derivados de formações vulcânicas (de idade variável), ocorrendo sob climas temperados e tropicais. Os resultados obtidos mostram que os materiais amorfos determinados a partir das curvas de dissolução encontram-se irregularmente distribuídos nas amostras estudadasinfo:eu-repo/semantics/publishedVersio

New insights into the genetic etiology of Alzheimer's disease and related dementias

Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

The Great Markarian 421 Flare of 2010 February: Multiwavelength Variability and Correlation Studies

We report on variability and correlation studies using multiwavelength observations of the blazar Mrk 421 during the month of 2010 February, when an extraordinary flare reaching a level of ∼27 Crab Units above 1 TeV was measured in very high energy (VHE) γ-rays with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) observatory. This is the highest flux state for Mrk 421 ever observed in VHE γ-rays. Data are analyzed from a coordinated campaign across multiple instruments, including VHE γ-ray (VERITAS, Major Atmospheric Gamma-ray Imaging Cherenkov), high-energy γ-ray (Fermi-LAT), X-ray (Swift, Rossi X-ray Timing Experiment, MAXI), optical (including the GASP-WEBT collaboration and polarization data), and radio (Metsahovi, Owens Valley Radio Observatory, University of Michigan Radio Astronomy Observatory). Light curves are produced spanning multiple days before and after the peak of the VHE flare, including over several flare "decline" epochs. The main flare statistics allow 2 minute time bins to be constructed in both the VHE and optical bands enabling a cross-correlation analysis that shows evidence for an optical lag of ∼25-55 minutes, the first time-lagged correlation between these bands reported on such short timescales. Limits on the Doppler factor (δ ⪆ 33) and the size of the emission region (δ-1RB≲ 3.8 × 1013cm) are obtained from the fast variability observed by VERITAS during the main flare. Analysis of 10 minute binned VHE and X-ray data over the decline epochs shows an extraordinary range of behavior in the flux-flux relationship, from linear to quadratic to lack of correlation to anticorrelation. Taken together, these detailed observations of an unprecedented flare seen in Mrk 421 are difficult to explain with the classic single-zone synchrotron self-Compton model.</p

Nomenclature And Guideline To Express The Amount Of A Membrane Protein Synthesized In Animal Cells In View Of Bioprocess Optimization And Production Monitoring

Studies of a bioprocess optimization and monitoring for protein synthesis in animal cells face a challenge on how to express in quantitative terms the system performance. It is possible to have a panel of calculated variables that fits more or less appropriately the intended goal. Each mathematical expression approach translates different quantitative aspects. We can basically separate them into two categories: those used for the evaluation of cell physiology in terms of product synthesis, which can be for bioprocess improvement or optimization, and those used for production unit sizing and for bioprocess operation. With these perspectives and based on our own data of kinetic S2 cells growth and metabolism, as well as on their synthesis of the transmembrane recombinant rabies virus glycoprotein, here indicated as P, we show and discuss the main characteristics of calculated variables and their recommended use. Mainly applied to a bioprocess improvement/optimization and that mainly used for operation definition and to design the production unit, we expect these definitions/recommendations would improve the quality of data produced in this field and lead to more standardized procedures. In turn, it would allow a better and easier comprehension of scientific and technological communications for specialized readers. © 2009 The International Association for Biologicals.381105112Yokomizo, A.Y., Jorge, S.A.C., Astray, R.M., Fernandes, I., Ribeiro, O.G., Horton, D.S.P.Q., Rabies virus glycoprotein expression in Drosophila S2 cells. I. Functional recombinant protein in stable co-transfected cell line (2007) Biotechnol J, 2, pp. 102-109Astray, R.M., Augusto, E.F.P., Yokomizo, A.Y., Pereira, C.A., Analytical approach for the extraction of recombinant membrane viral glycoprotein from stably transfected Drosophila melanogaster cells (2008) Biotechnol J, 3, pp. 98-103Aiba, S., Humphrey, A.E., Millis, N.F., (1973) Biochemical engineering. 2nd ed., , Academic Press, New YorkBailey, J.E., Ollis, D.F., (1986) Biochemical engineering fundamentals. 2nd ed., , McGraw-Hill, New YorkShuler, M.L., Kargi, F., (2002) Bioprocess engineering basic concepts. 2nd ed., , Prentice-Hall PTR, Upper SaddleAdams, D., Korke, R., Hu, W.S., Application of stoichiometric and kinetic analyses to characterize cell growth and product formation (2007) Animal cell biotechnology: methods and protocols. 2nd ed., pp. 269-284. , Pörtner R. (Ed), Humana Press, TutowaDoyle, A., Griffiths, J.B., (1998) Cell and tissue culture: laboratory procedures in biotechnology, , p. 133-59, Wiley, NYTey, B.T., Al-Rubeai, M., Suppression of apoptosis in perfusion culture of myeloma NS0 cells enhanced cell growth but reduces antibody productivity (2004) Apoptosis, 9, pp. 843-852Wurm, F.M., Production of recombinant protein therapeutics in cultivated mammalian cells (2004) Nat Biotechnol, 22, pp. 1393-1398Ma, Z., Yi, X., Zhang, Y., Enhanced intracellular accumulation of recombinat HbsAg in CHO cells by dimethyl sulfoxide (2008) Process Biochem, 43, pp. 690-695Jorge, S.A.C., Santos, A.S., Spina, A., Pereira, C.A., Expression of the hepatitis B vírus surface antigen in Drosophila S2 cells (2008) Cytotechnol, 57, pp. 51-59Galesi, A.L.L., Aguiar, M.A., Astray, R.M., Augusto, E.F.P., Moraes, A.M., Growth of recombinant Drosophila melanogaster Schneider 2 cells producing rabies virus glycoprotein in bioreactor employing serum-free medium (2008) Cytotechnol, 57, pp. 73-81Pamboukian, M.M., Jorge, S.A.C., Santos, M.G., Yokomizo, A.Y., Pereira, C.A., Tonso, A., Insect cells respiratory activity in bioreactor (2008) Cytotechnol, 57, pp. 37-44Swiech, K., Rossi, N., Astray, R.M., Suazo, C.A., Enhanced production of recombinant rabies virus glycoprotein (rRVGP) by Drosophila melanogaster S2 cells through control of culture conditions (2008) Cytotechnol, 57, pp. 51-59Freshney, R.I., (1994) Culture of animal cells: a manual of basic technique. 3rd ed., , Wiley-Liss,, New YorkAugusto, E.F.P., Barral, M.F., Piccoli, R.A.M., Mathematical models for growth and product synthesis in animal cell culture (2008) Animal cell technology: from biopharmaceuticals to gene therapy, pp. 181-220. , Castilho L.R., Moraes A.M., Augusto E.F.P., and Butler M. (Eds), Taylor & Francis, London. 978041542304

NMR solution structure of Ole e 6, a major allergen from olive tree pollen

Ole e 6 is a pollen protein from the olive tree (Olea europaea) that exhibits allergenic activity with a high prevalence among olive-allergic individuals. The three-dimensional structure of Ole e 6 has been determined in solution by NMR methods. This is the first experimentally determined structure of an olive tree pollen allergen. The structure of this 50-residue protein is based on 486 upper limit distance constraints derived from nuclear Overhauser effects and 24 ϕ torsion angle restraints. The global fold of Ole e 6 consists of two nearly antiparallel α-helices, spanning residues 3-19 and 23-33, that are connected by a short loop and followed by a long, unstructured C-terminal tail. Viewed edge-on, the structured N terminus has a dumbbell-like shape with the two helices on the outside and with the hydrophobic core, mainly composed of 3 aromatic and 6 cysteine residues, on the inside. All the aromatic rings lie on top of and pack against the three disulfide bonds. The lack of thermal unfolding, even at 85 °C, indicates a high conformational stability. Based on the analysis of the molecular surface, we propose five plausible epitopes for IgE recognition. The results presented here provide the structural foundation for future experiments to verify the antigenicity of the proposed epitopes, as well as to design novel hypoallergenic forms of the protein suitable for diagnosis and treatment of type-I allergies. In addition, three-dimensional structure features of Ole e 6 are discussed to provide a basis for future functional studies.This work was supported by Grant CAM2002-07B/0054 from the Comunidad Autónoma de Madrid and Grant SAF2002-02711 from the Ministerio de Ciencia y Tecnología (Spain)

Kinetic analysis of in vitro production of wild-type Spodoptera frugiperda nucleopolyhedrovirus

In this study, the kinetic behavior of Sf9 and Sf21 cells used in the production of a baculovirus biopesticide to control the pest of corn Spodoptera frugiperda was analyzed. Kinetic variables such as maximum specific growth rate, cell productivity, mean rate of infection, as well as the mean rate of occlusion body production were determined during the infection of these cell-lines with the extracellular virus of the S. frugiperda nucleopolyhedrovirus (SfMNPV). The Sf9 cell-line resulted in better viral production results (5.0 x 10 OB/mL) than the Sf21 cell-line (2.5 x 10 OB/mL)

Molecular Mechanisms of Yeast Cell Wall Glucan Remodeling*

Yeast cell wall remodeling is controlled by the equilibrium between glycoside hydrolases, glycosyltransferases, and transglycosylases. Family 72 glycoside hydrolases (GH72) are ubiquitous in fungal organisms and are known to possess significant transglycosylase activity, producing elongated β(1–3) glucan chains. However, the molecular mechanisms that control the balance between hydrolysis and transglycosylation in these enzymes are not understood. Here we present the first crystal structure of a glucan transglycosylase, Saccharomyces cerevisiae Gas2 (ScGas2), revealing a multidomain fold, with a (βα)8 catalytic core and a separate glucan binding domain with an elongated, conserved glucan binding groove. Structures of ScGas2 complexes with different β-glucan substrate/product oligosaccharides provide “snapshots” of substrate binding and hydrolysis/transglycosylation giving the first insights into the mechanisms these enzymes employ to drive β(1–3) glucan elongation. Together with mutagenesis and analysis of reaction products, the structures suggest a “base occlusion” mechanism through which these enzymes protect the covalent protein-enzyme intermediate from a water nucleophile, thus controlling the balance between hydrolysis and transglycosylation and driving the elongation of β(1–3) glucan chains in the yeast cell wall