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Search Results: 1 - 10 of 208841 matches for " Hernán Terenzi "
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Extracellular Proteins of Mycoplasma synoviae
Manuel Sebastián Rebollo Couto,Catia Silene Klein,Daiane Voss-Rech,Hernán Terenzi
ISRN Veterinary Science , 2012, DOI: 10.5402/2012/802308
Abstract: Mycoplasma synoviae is a Gram positive bacteria lacking of cell wall that affects chickens and turkeys causing infection in the upper respiratory tract and in some cases arthritis, with economical impact to broiler breeders. Treatment and prevention of avian synovitis depend on knowledge of the infectious process. Secreted or surface-exposed proteins play a critical role in disease because they often mediate interactions between host and pathogen. In the present work, we sought to identify possible M. synoviae secreted proteins by cultivating the bacteria in a modified protein-free Frey medium. Using this approach, we were able to detect in the cell-free fraction a number of proteins that have been shown in other organisms to be secreted, suggesting that they may also be secreted by M. synoviae. 1. Introduction The growth of poultry industry is often limited by infectious diseases that affect birds. Mycoplasma synoviae is a major avian extracellular pathogen associated with synovitis in chickens and turkeys [1, 2]. Disease can occur as chronical subclinical to severe upper respiratory infection and, under unknown conditions, become systemic and cause arthritis [3]. The disease causes economic losses by retarding growth and downgrading at slaughter [3]. Strategies to control this pathogen rely mainly in better management practices, improvement in housing conditions and antibiotic usage, whereas an effective vaccine is still not available [4]. Secreted proteins of pathogenic bacteria are key factors in host colonization. The analysis of these proteins, called secretome, can therefore permit the identification of new putative virulence factors that are fundamental for host invasion and survival in the environment within the host [5]. In this context, two-dimensional electrophoresis (2DE) along with peptide fingerprinting by mass spectrometry (MS) and subsequent protein identification have become a powerful method to unravel pathogenicity factors in microorganisms [6, 7]. We have recently reported a proteomic analysis of M. synoviae cell extracts in conventional Frey medium [8]. In the present work, we have grown M. synoviae in the same typical culture medium and then incubated the cells in a protein-free modified Frey medium as a strategy to indicate proteins that can be secreted to the medium by the bacteria. 2. Methods 2.1. Mycoplasma synoviae Cultures M. synoviae strain 53 isolated from a broiler breeder was grown in the Laboratory of Genetics and Animal Health from EMBRAPA Swine and Poultry (Concórdia, C, Brazil) as described by Frey and coworkers
Estratégias utilizadas no combate a resistência bacteriana
Silveira, Gustavo Pozza;Nome, Faruk;Gesser, José Carlos;Sá, Marcus Mandolesi;Terenzi, Hernán;
Química Nova , 2006, DOI: 10.1590/S0100-40422006000400037
Abstract: this article provides an overview on the recent achievements to combat gram-positive bacteria and the mechanisms related to antimicrobial activity and bacterial resistance. selected synthetic methodologies to access structurally diverse bioactive compounds are presented in order to emphasize the most important substances currently developed to overcome multiresistant strains. the main properties of vancomycin and related glycopeptide antibiotics are also discussed as a background to understanding the design of new chemotherapeutic agents.
Extracellular Proteins of Mycoplasma synoviae
Manuel Sebastián Rebollo Couto,Catia Silene Klein,Daiane Voss-Rech,Hernán Terenzi
ISRN Veterinary Science , 2012, DOI: 10.5402/2012/802308
Abstract:
Platinum(II) compounds of tetracyclines as potential anticancer agents: cytotoxicity, uptake and interactions with DNA
Silva, Priscila P.;Paula, Flávia C. S. de;Guerra, Wendell;Silveira, Josianne N.;Botelho, Fran?oise V.;Vieira, Leda Q.;Bortolotto, Tiago;Fischer, Franciele L.;Bussi, Giselle;Terenzi, Hernán;Pereira-Maia, Elene C.;
Journal of the Brazilian Chemical Society , 2010, DOI: 10.1590/S0103-50532010000700011
Abstract: the antitumoral properties of ptii compounds and the favorable characteristics of tetracyclines led us to study ptii compounds of tetracycline (tc) and doxycycline (dox) as candidates for anticancer agents. [ptcl2(dox)], 1, is more potent than [ptcl2(tc)], 2, in inhibiting the growth of chronic myelogenous leukemia cells. compounds 1 and 2 form a ternary complex with dna withk values of 3.85×104 and 5.43×104, respectively. the compounds displace ethidium bromide from dna sites, which points to an intercalative mechanism. both complexes decrease dna eletrophoretic mobility and melting temperature. after incubation of cells with 1 and 2, the dna was extracted and the adducts formed were quantified. at the concentration that the compounds are cytotoxic to cancer cells, they do not affect macrophages viability. the rate of uptake of the doxycycline complex in cells is three times higher than that of the tetracycline complex and this seems to be determinant for its higher activity.
Catalytic promiscuity: catecholase-like activity and hydrolytic DNA cleavage promoted by a mixed-valence FeIII FeII complex
Neves, Ademir;Bortoluzzi, Adailton J.;Jovito, Rafael;Peralta, Rosely A.;Souza, Bernardo de;Szpoganicz, Bruno;Joussef, Ant?nio C.;Terenzi, Hernán;Severino, Patricia C.;Fischer, Franciele L.;Schenk, Gerhard;Riley, Mark J.;Smith, Sarah J.;Gahan, Lawrence R.;
Journal of the Brazilian Chemical Society , 2010, DOI: 10.1590/S0103-50532010000700007
Abstract: catalytic promiscuity has emerged as an important property of many enzymes since the relationship of this property to enzymatic evolution became clear. simultaneously, the development of suitable biomimetic catalytic systems capable of mimicking the promiscuous catalytic properties of such enzymes represents a new challenge for bioinorganic chemists. in this paper we report on the x-ray structure, the solution studies and the promiscuous catalytic activity of the mixed-valence complex [(bpbpmp)feiii(μ-oac)2feii](clo4), (1), containing the unsymmetrical dinucleating ligand 2-{[(2-hydroxybenzyl)(2-pyridylmethyl)aminomethyl]-4-methyl-6-[bis(2-pyridylmethyl)aminomethyl]}phenol (h2bpbpmp). potentiometric and spectrophotometric titrations and kinetics studies showed that this coordination compound generates active species that promote hydrolytic cleavage of double strand dna (dsdna), with a rate enhancement of 1.9×108 over the non-catalyzed reaction, as well as promote oxidation of 3,5-di-tert-butylcatechol (3,5-dtbc), with kcat = 1.16 × 10-2 s-1 and km = 7.1×10-4 mol l-1. thus, complex 1 shows both hydrolase and oxidoreductase activities and can be regarded as a man-made model for studying catalytic promiscuity.
Discovery of Mycobacterium tuberculosis Protein Tyrosine Phosphatase B (PtpB) Inhibitors from Natural Products
Alessandra Mascarello, Mattia Mori, Louise Domeneghini Chiaradia-Delatorre, Angela Camila Orbem Menegatti, Franco Delle Monache, Franco Ferrari, Rosendo Augusto Yunes, Ricardo José Nunes, Hernán Terenzi, Bruno Botta, Maurizio Botta
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0077081
Abstract: Protein tyrosine phosphatase B (PtpB) is one of the virulence factors secreted into the host cell by Mycobacterium tuberculosis. PtpB attenuates host immune defenses by interfering with signal transduction pathways in macrophages and, therefore, it is considered a promising target for the development of novel anti-tuberculosis drugs. Here we report the discovery of natural compound inhibitors of PtpB among an in house library of more than 800 natural substances by means of a multidisciplinary approach, mixing in silico screening with enzymatic and kinetics studies and MS assays. Six natural compounds proved to inhibit PtpB at low micromolar concentrations (< 30 μM) with Kuwanol E being the most potent with Ki = 1.6 ± 0.1 μM. To the best of our knowledge, Kuwanol E is the most potent natural compound PtpB inhibitor reported so far, as well as it is the first non-peptidic PtpB inhibitor discovered from natural sources. Compounds herein identified may inspire the design of novel specific PtpB inhibitors.
Analysis, Design, and Construction of a Base-Isolated Multiple Building Structure
Stefano Sorace,Gloria Terenzi
Advances in Civil Engineering , 2014, DOI: 10.1155/2014/585429
Abstract: The analysis and design of a multiple residential building, seismically protected by a base isolation system incorporating double friction pendulum sliders as protective devices, are presented in the paper. The building, situated in the suburban area of Florence, is composed of four independent reinforced concrete framed structures, mutually separated by three thermal expansion joints. The plan is L-shaped, with dimensions of about 75?m in the longitudinal direction and about 30?m along the longest side of the transversal direction. These characteristics identify the structure as the largest example of a base-isolated “artificial ground” ever built in Italy. The base isolation solution guarantees lower costs, a much greater performance, and a finer architectural look, as compared to a conventional fixed-base antiseismic design. The characteristics of the building and the isolators, the mechanical properties and the experimental characterization campaign and preliminary sizing carried out on the latter, and the nonlinear time-history design and performance assessment analyses developed on the base isolated building are reported in this paper, along with details about the installation of the isolators and the plants and highlights of the construction works. 1. Introduction Base isolation is nowadays a well-established and viable antiseismic design strategy for new buildings and bridges, as well as for the retrofit of existing ones, with several thousand applications in over 30 earthquake-prone countries worldwide. The use of this technology, originally restricted to massive and stiff structures, has been progressively extended in the past decade to include slender and high-rise buildings, as well as groups of structures built on a single platform (also labelled as “artificial ground”) [1]. This is a consequence of the increase in the fundamental vibration period targeted in base-isolated conditions, following the incorporation of the latest generation of isolators, characterized by very low translational stiffness. The period, normally fixed at 2–2.5?s in early designs, was subsequently raised to 3–3.5?s, for standard buildings, and to over 4?s, for special structures. This allowed extending the benefits of seismic isolation to wider classes of applications, that is, the new structural configurations above and other notably demanding conditions, and, namely, significant geometrical irregularities in plan and/or elevation [2]; possible effects of near-fault earthquake components in the construction site [3–6]; a trend towards marked reductions in width of
Wavelet entropy filter and cross-correlation of gravitational wave data
R. Terenzi,R. Sturani
Physics , 2009,
Abstract: We present a method for enhancing the cross-correlation of gravitational wave signals eventually present in data streams containing otherwise uncorrelated noise. Such method makes use of the wavelet decomposition to cast the cross-correlation time series in time-frequency space. Then an entropy criterion is applied to identify the best time frequency resolution, i.e. the resolution allowing to concentrate the signal in the smallest number of wavelet coefficients. By keeping only the coefficients above a certain threshold, it is possible to reconstruct a cross-correlation time series where the effect of common signal is stronger. We tested our method against signals injected over two data streams of uncorrelated white noise.
Adaptive multiresolution for wavelet analysis
Riccardo Sturani,Roberto Terenzi
Physics , 2007, DOI: 10.1088/1742-6596/122/1/012036
Abstract: We present a new method of wavelet packet decomposition to be used in gravitational wave detection. An issue in wavelet analysis is what is the time-frequency resolution which is best suited to analyze data when in quest of a signal of unknown shape, like a burst. In the other wavelet methods currently employed, like LIGO WaveBurst, the analysis is performed at some trial resolutions. We propose a decomposition which automatically selects at any frequency the best resolution. The criterion for resolution selection is based on minimization of a function of the data, named entropy in analogy with the information theory. As a qualitative application we show how a multiresolution time-frequency scalogram looks in the case of a sample signal injected over Gaussian noise. For a more quantitative application of the method we tested its efficiency as a non-linear filter of simulated data for burst searches, finding that it is able to lower the false alarm rate of the WaveBurst algorithm with negligible effects on the efficiency.
Blowdown of hydrocarbons pressure vessel with partial phase separation
Alessandro Speranza,Alessandro Terenzi
Physics , 2011, DOI: 10.1142/9789812701817_0046
Abstract: We propose a model for the simulation of the blowdown of vessels containing two-phase (gas-liquid) hydrocarbon fluids, considering non equilibrium between phases. Two phases may be present either already at the beginning of the blowdown process (for instance in gas-liquid separators) or as the liquid is formed from flashing of the vapor due to the cooling induced by pressure decrease. There is experimental evidence that the assumption of thermodynamic equilibrium is not appropriate, since the two phases show an independent temperature evolution. Thus, due to the greater heat transfer between the liquid phase with the wall, the wall in contact with the liquid experiences a stronger cooling than the wall in contact with the gas, during the blowdown. As a consequence, the vessel should be designed for a lower temperature than if it was supposed to contain vapor only. Our model is based on a compositional approach, and it takes into account internal heat and mass transfer processes, as well as heat transfer with the vessel wall and the external environment. Numerical simulations show a generally good agreement with experimental measurements.
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