Whole genome sequencing of Mycobacterium tuberculosis reveals slow growth and low mutation rates during latent infections in humans

Very little is known about the growth and mutation rates of Mycobacterium tuberculosis during latent infection in humans. However, studies in rhesus macaques have suggested that latent infections have mutation rates that are higher than that observed during active tuberculosis disease. Elevated mutation rates are presumed risk factors for the development of drug resistance. Therefore, the investigation of mutation rates during human latency is of high importance. We performed whole genome mutation analysis of M. tuberculosis isolates from a multi-decade tuberculosis outbreak of the New Zealand Rangipo strain. We used epidemiological and phylogenetic analysis to identify four cases of tuberculosis acquired from the same index case. Two of the tuberculosis cases occurred within two years of exposure and were classified as recently transmitted tuberculosis. Two other cases occurred more than 20 years after exposure and were classified as reactivation of latent M. tuberculosis infections. Mutation rates were compared between the two recently transmitted pairs versus the two latent pairs. Mean mutation rates assuming 20 hour generation times were 5.5X10⁻¹⁰ mutations/bp/generation for recently transmitted tuberculosis and 7.3X10⁻¹¹ mutations/bp/generation for latent tuberculosis. Generation time versus mutation rate curves were also significantly higher for recently transmitted tuberculosis across all replication rates (p = 0.006). Assuming identical replication and mutation rates among all isolates in the final two years before disease reactivation, the u20hr mutation rate attributable to the remaining latent period was 1.6×10⁻¹¹ mutations/bp/generation, or approximately 30 fold less than that calculated during the two years immediately before disease. Mutations attributable to oxidative stress as might be caused by bacterial exposure to the host immune system were not increased in latent infections. In conclusion, we did not find any evidence to suggest elevated mutation rates during tuberculosis latency in humans, unlike the situation in rhesus macaques

Guida al recupero dell'architettura tradizionale e del paesaggio del territorio del G.A.L. Mongioie

La Guida per il recupero dell’architettura tradizionale e del paesaggio del G.A.L. Mongioie si configura come linee di indirizzo a supporto del processo progettuale di interventi di recupero del patrimonio architettonico a carattere tradizionale e del paesaggio rurale, caratteristico del territorio del G.A.L. Mongioie

Electroformation of quasi-two-dimensional silver patterns in the absence of supporting electrolyte

Quasi-two-dimensional (2D) growth patterns of silver electrodeposits obtained from aqueous silver sulfate solution in the absence of supporting electrolyte using a quasi-2D cylindrical cell involve domains with morphologies covering from dense to needle-like branching. The prevailing morphology depends on the electrolyte concentration, applied electric potential and electrolysis time. From the time dependence of the maximum radius circumscribing each electrodeposit, its dimension was obtained. The growth of the solid phase was also analysed in terms of dimensionless numbers to estimate the ionic mass-transfer contributions to the electrochemical process. For a single-growing branch the axial-to-radial growth velocity is close to 10. Phenomena promoting silver electrodeposits with irregular edges and an open structure compete with others operating in the opposite direction. These phenomena are influenced by changes in the concentration and electric potential field around the growing electrodeposit.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Growth of columnar gold electrodes by electroreducing hydrous gold oxide layers : Kinetics and mechanistic interpretation

Rough columnar structured gold electrodeposits were prepared in aqueous 0.5 M M H2SO4 by electroreducing a hydrous gold oxide layer built up on a gold substrate by means of a fast periodic potential routine. The analysis of potentiodynamic and potentiostatic hydrous oxide layer electroreduction data indicated the initial nucleation of gold clusters at the metals|oxide interface. The growth of gold nuclei proceeded under a constant capture area condition for depositing gold ions contained in the hydrous oxide layer. Columnar gold electrodeposition was assisted by the gel-like characteristics of the hydrous gold oxide layer. Gold columnar growth ended as soon as the column tips reached the oxide s| solution interfacc. The proposed kinetic model accounts for the high surface area development and surface fractal properties of this type of metal electrode.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Revelar la mirada

Solo se puede amar y respetar lo que se conoce, por lo tanto desde el Área de Plástica se trata de visibilizar de qué manera se pone en contacto a los niños y a las niñas de nuestra escuela con la naturaleza, la igualdad de género, la participación social y diversas manifestaciones artísticas y culturales. La formación plástico-visual representa una experiencia de acción y reflexión, un bagaje cultural y una posibilidad de interacción social. Formar a las y los estudiantes en una educación global es concebir el aprendizaje como modos de mirar y modos de pensar la comunicación visual, cuyo lenguaje debe ser conocido e interpretado. Las artes visuales configuran un fenómeno vasto que se aborda como hecho estético, expresivo y comunicativo, como signo, como artefacto de cultura infantil, como conducta evolutiva y como una combinación de diferentes perspectivas, construyendo un sentido expresivo, constructivo- lingüístico y productivo. Así, el espacio Artes Visuales debe buscar no solo el desarrollo de la expresividad del mundo interno, sino que debe posibilitar la alfabetización visual que permita proporcionar un sentido a la construcción de las imágenes.Facultad de ArtesEscuela Graduada Joaquín V. Gonzále

Kinetics and growth modes of quasi-2d silver branched electrodeposits produced in the presence of a supporting electrolyte

Quasi-2d silver electrodeposits were grown electrochemically at constant potential from aqueous Ag+ ion-containing solutions in the presence of a supporting electrolyte, at room temperature, using a three-electrode quasi-2d circular electrochemical cell. Open branching and dense radial branching patterns were distinguished on the centimetre scale, and growth mode transitions could be observed during the process. Branching patterns exhibited a mass fractal behaviour with a mass fractal dimension increasing from that expected for a DLA-like pattern to that of a dense branching pattern as either the cathodic overpotential (ηc) or the Ag+ ion concentration in the solution (c) was increased. The electrodeposition current increased with time exhibiting different regimes depending on whether an open branching or a dense radial branching growth mode prevailed. When the electrodeposition time exceeded a certain critical value, the radial growth rate of electrodeposits (vr) approached a vr α ηcc relationship. The experimental morphologies and growth kinetics were reproduced by Monte Carlo simulations of a growth model in which depositing particles follow a biased random walk.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Growth of three-dimensional silver fractal electrodeposits under damped free convection

Quasispherical three-dimensional Ag electrodeposits grown at constant potential and damped free convection exhibit a quasi-isotropic radial growth up to a critical radius rc≃0.3 cm and a mass fractal dimension DM=2.5. For r≫rc, DM→3. The product vrη’ is nearly constant, vr being the radial growth velocity, and η’ the apparent medium viscosity. It appears that vr is determined by the Laplacian field operating between cathode and anode.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Mass-transport-induced kinetic transitions during the electrochemical formation of three-dimensional dendritic silver deposits under ohmic control

The influence of mass transport processes on the growth of three-dimensional dendritic Ag deposits on a Pt quasi-spherical substrate at a relatively large cathodic overpotential has been investigated. After a certain induction time a first stage of dendritic growth of Ag can be observed. The deposit formed at this stage exhibits a fractal surface and non-fractal mass—volume properties. For charge densities greater than a certain critical value, a second stage of growth can be distinguished. At this second stage the contribution of free convection changes the shape of the deposit. The fastest growth of the Ag electrodeposit is determined by the rate of migration of sulphate ions in the electric field. A model accounting for the parametric relationships derived from the experiments is presented.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

1H NMR spectroscopy of glioblastoma stem-like cells identifies alpha-aminoadipate as a marker of tumor aggressiveness

Patients suffering from glioblastoma multiforme (GBM) face a poor prognosis with median survival of about 14months. High recurrence rate and failure of conventional treatments are attributed to the presence of GBM cells with stem-like properties (GSCs). Metabolite profiles of 42 GSC lines established from the tumor tissue of adult GBM patients were screened with 1H NMR spectroscopy and compared with human neural progenitor cells from human adult olfactory bulb (OB-NPCs) and from the developing human brain (HNPCs). A first subset (n=12) of GSCs exhibited a dramatic accumulation of the metabolite α-aminoadipate (αAAD), product of the oxidation of α-aminoadipic semialdehyde catalyzed by the ALDH7A1 aldehyde dehydrogenase (ALDH) family in lysine catabolism. αAAD was low/not detectable in a second GSC subset (n=13) with the same neural metabolic profile as well as in a third GSC subset (n=17) characterized by intense lipid signals. Likewise, αAAD was not detected in the spectra of OB-NPCs or HNPCs. Inhibition of mitochondrial ATP synthase by oligomycin treatment revealed that the lysine degradative pathway leading to αAAD formation proceeds through saccharopine, as usually observed in developing brain. Survival curves indicated that high αAAD levels in GSCs significantly correlated with poor patient survival, similarly to prostate and non-small-cell-lung cancers, where activity of ALDH7A1 correlates with tumor aggressiveness