Cytotoxicity and Membrane Interaction of Tamoxifen as Affected by Ca2+ and Mg2+: Use of a Bacterial Model System

A strain of Bacillus stearothermophilus was used as a model to study the interaction of tamoxifen (TAM) with the membrane and the cytostatic antiproliferative effects not related to estrogen binding. TAM inhibits the growth of B. stearothermophilus as a function of concentration. The supplementation of the growth medium with Ca2+ or Mg2+ partially relieves the growth inhibition by TAM, allowing growth at TAM concentrations that fully impair growth in the basal medium. Fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) and of its propionic acid derivative (DPH-PA) reveals opposite effects induced by TAM and Ca2+. The addition of Ca2+ to liposomes of bacterial lipids promoted physical ordering as opposed to disordering induced by TAM. Thus, it is predictable that growth impairment induced by TAM is mediated through perturbations at the membrane level.http://www.sciencedirect.com/science/article/B6TCP-3X3K8KK-Y/1/c91ad40c71c69da7245d8f09c634d28

Synthesis and Functionalization of Monodisperse Near-ultraviolet and Visible Excitable Multifunctional Eu3+, Bi3+:REVO4 Nanophosphors for Bioimaging and Biosensing Applications

Near-ultraviolet and visible excitable Eu- and Bi-doped NPs based on rare earth vanadates (REVO4, RE = Y, Gd) have been synthesized by a facile route from appropriate RE precursors, europium and bismuth nitrate, and sodium orthovanadate, by homogeneous precipitation in an ethylene glycol/water mixture at 120 °C. The NPs can be functionalized either by a one-pot synthesis with polyacrylic acid (PAA) or by a Layer-by-Layer approach with poly(allylamine hydrochloride) (PAH) and PAA. In the first case, the particle size can also be tuned by adjusting the amount of PAA. The Eu- Bi-doped REVO4 based nanophosphors show the typical red luminescence of Eu(III), which can be excited through an energy transfer process from the vanadate anions, resulting in a much higher luminescence intensity in comparison to the direct excitation of the europium cations. The incorporation of Bi into the REVO4 structure shifts the original absorption band of the vanadate anions towards longer wavelengths, giving rise to nanophosphors with an excitation maximum at 342 nm, which can also be excited in the visible range. The suitability of such nanophosphors for bioimaging and biosensing applications, as well as their colloidal stability in different buffer media of biological interest, their cytotoxicity, their degradability at low pH, and their uptake by HeLa cells have been evaluated. Their suitability for bioimaging and biosensing applications is also demonstrated.European Union 267226Ministerio de Economía y Competitividad MAT2014-54852-

Rare earth based nanostructured materials: Synthesis, functionalization, properties and bioimaging and biosensing applications

Rare earth based nanostructures constitute a type of functional materials widely used and studied in the recent literature. The purpose of this review is to provide a general and comprehensive overview of the current state of the art, with special focus on the commonly employed synthesis methods and functionalization strategies of rare earth based nanoparticles and on their different bioimaging and biosensing applications. The luminescent (including downconversion, upconversion and permanent luminescence) and magnetic properties of rare earth based nanoparticles, as well as their ability to absorb X-rays, will also be explained and connected with their luminescent, magnetic resonance and X-ray computed tomography bioimaging applications, respectively. This review is not only restricted to nanoparticles, and recent advances reported for in other nanostructures containing rare earths, such as metal organic frameworks and lanthanide complexes conjugated with biological structures, will also be commented on.European Union 267226Ministerio de Economía y Competitividad MAT2014-54852-

Estabilidad de rendimiento de diez genotipos de trigo (triticum aestivum l.) en cinco localidades de Huánuco

The objective of this study was to determine the level of yield stability of ten wheat genotypes (Triticum aestivum L.) in five places in Huánuco Region during the crop in 2011, using the design of a randomized complete block. The combined analysis of variance showed highly significant genotype differences for places. In Chaulan (3237 m) was the most favorable environment for the yield of genotypes. Stressed the genotypes ALTAR 84 / AEGILOPS SQUARROSA (TAUS) ..., CHEN / AE. Q / / 2 * OPATA / 3 / BABAX / 4 / JARU and WORRAKATTA / 2 * PASTOR, for showing yields close to 3 000 kg / ha and favorable combinations of parameters bi S2di stability. The national CENTENARIO UNALM showed simultaneous stability and consistency and a performance of 2 835 kg / ha, making it a good indicator of wide adaptability.El objetivo de la investigación fue conocer el nivel de estabilidad del rendimiento de diez genotipos de trigo (Triticum aestivum L.) en cinco localidades de la sierra de la Región de Huánuco durante la campaña agrícola 2011, empleando el diseño de bloque completos al azar. El análisis de varianza combinado mostró diferencias altamente significativas para la interacción genotipo por localidades. La localidad de Chaulán (3 237 msnm) fue el ambiente más favorable para la expresión del rendimiento de los genotipos. Destacaron los genotipos ALTAR 84 / AEGILOPS SQUARROSA (TAUS)…, CHEN / AE. Q // 2* OPATA /3/ BABAX /4/ JARU y WORRAKATTA / 2* PASTOR, por mostrar rendimientos próximos a los 3 000 kg/ha y combinaciones favorables de sus parámetros de estabilidad bi S2di. El testigo nacional CENTENARIO-UNALM mostró estabilidad y consistencia simultánea y un rendimiento de 2 835 kg/ha, constituyéndose en un buen indicador de amplia adaptabilidad

Comparative study of tributyltin toxicity on two bacteria of the genus Bacillus

Tributyltin is a potent biocide mainly used in marine antifouling paints. Owing to its widespread distribution in coast areas and its high toxicity to aquatic organisms, the use of this compound is generally restricted and under government regulation. Despite of that, it persists in the aquatic environment. Organotins used in industry have also been detected in terrestrial environments. The persistence and high lipophilicity explain bioaccumulation. The role of bacteria in recycling organic matter prompted us to study the interaction of tributyltin with two ubiquitous bacilli, B. stearothermophilus and B. subtilis, proposed as biological indicators of pollutants with ecological impact. These bacteria have been used as suitable models for the study of toxicity mechanisms of unselective lipophilic compounds (e.g., DDT and endosulfan). Drug effects on growth parameters, oxygen consumption and membrane organization were assessed. Bacteria growth in a liquid complex medium was disturbed by concentrations of TBT as low as 25 nM (8 [mu]g L-1), close to the concentration in polluted environments. The respiratory activity is affected by TBT in both microorganisms. Membrane organization, assessed by fluorescence polarization of two fluidity probes, 1,6-diphenyl-1,3,5-hexatriene (DPH) and a propionic acid derivative (DPH-PA), was also perturbed by the xenobiotic. Alterations on growth, oxygen consumption and physical properties of membrane lipids are stronger in B. stearothermophilus as compared to B. subtilis. A putative relationship between growth inhibition and respiratory activity impairment induced by TBT and its effects on the physical behaviour of bacterial membrane lipids is suggested.http://www.sciencedirect.com/science/article/B6TCP-4GSJR3R-9/1/18e0ee5c8ce4e887466d84b850ad8ec

Toxicity of methoprene as assessed by the use of a model microorganism

Methoprene is an insect juvenile growth hormone mimic, commonly used as a pesticide. Although widely used for the control of several pests, toxic effects on organisms of different phyla have been reported. These events triggered studies to clarify the mechanisms of toxicity of this insecticide putatively involved in ecological issues. Here we show the effect of methoprene on the normal cell growth and viability of a strain of the thermophilic eubacterium Bacillus stearothermophilus, previously used as a model for toxicological evaluation of other environment pollutants. Respiration studies were also carried out attempting to identify a putative target for the cytotoxic action of methoprene. Cell growth was affected and a decrease of the number of viable cells was observed as a result of the addition of methoprene to the growth medium, an effect reverted by the presence of Ca2+. Methoprene also inhibited the redox flow of B. stearothermophilus protoplasts before the cytochrome oxidase segment, an effect further studied by individually assessing the enzymatic activities of the respiratory complexes. This study suggests that methoprene membrane interaction and perturbation of cell bioenergetics may underlie the mechanism of toxicity of this compound in non-target organisms.http://www.sciencedirect.com/science/article/B6TCP-4GSJXGW-4/1/788f9fd7d4f3a4f1ae5d498a5674dcc

Biodeterioration of Roman tombs: The role of pigmented actinobacteria

Etruscan and Roman necropolises are cemeteries with different types of burial practices, which are remarkable for their magnificent mural paintings. The conservation of these paintings is difficult, mainly derived from environmental factors and the opening of the tombs to public visits. One of the most complex phenomena observed on these sites is biodeterioration. The Circular Mausoleum tomb (Roman Necropolis of Carmona, Seville, Spain) is characterized by a heavy colonization of phototrophic microorganisms on the walls and ceiling. In addition, some areas near the ceiling exhibited an important number of violet stains of unknown origin. Previously, Agarossi (1994) found similar violet stains, attributed to streptomycetes, in two Etruscan tombs. However, no data on the species involved or the chemical structure of the pigments were reported. Here we show that the violet stains observed in the Circular Mausoleum are produced by a strain of the actinobacterium Streptomyces isolated from the mortar walls, and able to synthesize the same violet pigment in the laboratory. Streptomyces parvus MC05 was identified after whole genome study by means of Next Generation Sequencing methods. Pairwise comparisons carried out for genomes of the type strain of S. parvus DSM40348T and the MC05 strain were performed using Jspecies service. While results observed for ANIb, ANIm and Tetra indexes indicated that both strains belong to the same species, the S. parvus MC05 strain differs from the DSM20348T type strain in genome size and secondary metabolites production. AntiSMASH analysis implemented for both strains showed that the S. parvus MC05, isolated from the tomb, presents the capacity of synthesize bioactive compounds which were absents in the type strain. HPLC-MS of the culture extracts from S. parvus MC05 showed the production of three main granaticin derivatives (dihydrogranaticin A, granaticin A and granaticin B) in addition to minor products of other granaticin analogues. Granaticin pigments exhibited antibacterial activity, which justified the low number of clones of Gram positive bacteria found in the whole microbial community study. Gram negative bacteria were not affected (Dominguez-Moñino et al. 2017). To conclude, the origin of the violet stains in the walls of the Circular Mausoleum is the presence of S. parvus MC05, a member of the complex microbial community thriving on the tomb. In growing periods (rainy season) the bacterium excretes the soluble violet granaticins, compounds with a benzoisochromanequinone structure, which diffuses to the mortar and surrounding substrata in wetting periods

Inconsistencies in the description of pairing effects in nuclear level densities

Pairing correlations have a strong influence on nuclear level densities. Empirical descriptions and theoretical models have been developed to take these effects into account. The present article discusses cases, where descriptions of nuclear level densities are inconsistent or in conflict with the present understanding of nuclear properties. Phenomenological approaches consider a back-shift parameter. However, the absolute magnitude of the back-shift, which actually corresponds to the pairing condensation energy, is generally not compatible with the observation that stable pairing correlations are present in essentially all nuclei. It is also shown that in the BCS model pairing condensation energies and critical pairing energies are inconsistent for light nuclei. A modification to the composite Gilbert-Cameron level-density description is proposed, and the use of more realistic pairing theories is suggested.Comment: 17 pages, 3 figure