ZnII Complexes Based on Hybrid N-Pyrazole, N′-imine Ligands: Synthesis, X-Ray Crystal Structure, NMR Characterisation, and 3D Supramolecular Properties

The present report is on the synthesis of two new 3-imine-3,5-dimethylpyrazole ligands, N-[3-(3,5-dimethyl-1H-pyrazol- 1-yl)propylidene]ethylamine (L1) and N-[3-(3,5-dimethyl-1H-pyrazol-1-yl)propylidene]propylamine (L2). These ligands form molecular complexes with the formula [ZnCl2(L)] (L¼L1 (1) and L2 (2)) when the reacting with ZnCl2 in a metal (M)/ligand (L) ratio of 1 : 1. These new ZnII complexes have been characterised by elemental analyses, conductivity measurements, mass spectrometry, and infrared, 1H and 13C{1H} NMR spectroscopy techniques. The two crystalline structures of complexes 1 and 2 have been solved by X-ray diffraction methods. Finally, we have studied the self-assembly three-dimensional supramolecular structure through different intra- and intermolecular contacts. The application of these ZnII complexes in supramolecular crystal engineering is interesting due to (1) the easy preparation and the high efficiency of this system and (2) the different bonding properties of the heteroatoms (N-pyrazole vs N-imine) present in the structure of the ligands

EFECTO DE LA PRESENCIA DE FENANTRENO SOBRE LA EXPRESIÓN DE PROTEÍNAS Y LA ACTIVIDAD ENZIMÁTICA RADICAL DE CYPERUS HERMAPHRODITUS

Polycyclic aromatic hydrocarbons (PAH)are part of the petroleum contaminantsencountered in the environment. It has beenshown that soils supporting vegetation areeffective in removing and mineralizingthese contaminants; because plant rootshave phytoremediation-related proteinslike enzymatic systems linked to the plantcell wall that contribute to the remediationof contaminated sites. Through their directaction or by union they sequester, transformand transport organic contaminants.The aim of this work was to analyze changes in the expression of the soluble and theionically-bound cell wall root proteins andthe activity of certain enzymes consideredas biochemical markers in plants of Cyperushermaphroditus exposed to phenanthrene, atricyclic aromatic hydrocarbon. The effectof phenanthrene on the activity of the rootenzymes guaiacol peroxidases, ascorbateperoxidases, laccases and acid phosphatasesshowed significant differences between theenzymes of the soluble protein fraction andthe contaminant concentration. However,the enzymes of the ionically-bound cellwall fraction showed significant differencesonly among themselves, not with respectto the concentration of contaminant. Theresults showed that the amount of activityof constitutive enzymes and the induction orrepression of protein expression in plants ofC. hermaphroditus exposed to phenanthrene can be important mechanisms of plant reactions to contaminant toxicity or in partiallytransforming them to less toxic productsthat can be easily absorbed by the roots andsequestered in the plants.Los hidrocarburos aromáticos policíclicos(HAP) forman parte de los contaminantesderivados del petróleo que se encuentran enel ambiente y en particular se ha encontrado que los suelos con cubierta vegetal sonconsiderados altamente efectivos para laremoción y mineralización de éstos, ya quelas raíces de las plantas presentan proteínasrelacionadas con la fitorremediación, comoson algunos sistemas enzimáticos asociadosa la pared celular que contribuyen a la remediación de sitios contaminados a travésde la acción directa o por unión, secuestro,transformación y transporte de los contaminantes orgánicos.El objetivo de este trabajo fue analizar loscambios en la expresión de proteínas radicales solubles y unidas a la pared celular y laactividad de algunas enzimas consideradascomo marcadores bioquímicos de plantasde Cyperus hermaphroditus expuestas a fenantreno: un HAP tricíclico, con la finalidad de analizar fisiológicamente estossistemas radicales y constituir herramientasútiles para la transformación de contaminantes orgánicos. El efecto del fenantrenoen la actividad de guaiacol peroxidasas,ascorbato peroxidasas, lacasas y fosfatasasácidas radicales de C. hermaphroditus,mostró diferencias significativas entre lasenzimas solubles extraídas y la concentración del contaminante; mientras quelas enzimas unidas iónicamente a la paredcelular, solamente mostraron diferenciassignificativas entre ellas y no con respectoa la concentración del contaminante. Losresultados demostraron que la magnitud dela actividad de las enzimas constitutivas yde la expresión de proteínas en su induccióno represión bajo la presencia de fenantrenoen las plantas de Cyperus hermaphrodituspueden ser componentes importantes delas reacciones de plantas a la toxicidadde los contaminantes, o bien participar en latransformación parcial de éstos a productos menos tóxicos que puedan ser fácilmenteabsorbidos por las raíces y además ser confinados en el interior de la planta

EVALUACIÓN DEL CRECIMIENTO, ACTIVIDAD DE HEMOPEROXIDASAS Y REMOCIÓN DE FENANTRENO DE LOS CULTIVOS CELULARES DE FOUQUIERIA SPLENDENS Y FOUQUIERIA FASCICULATA

Knowledge about the metabolic potentialof plants to transform and degrade xenobiotics has been generated by analyzingresponses of in vitro plant cell cultures to contaminants, and these reactions havebeen considered a useful tool to evaluatethe phytotoxicity, metabolic rates and persistence of xenobiotics in plants. The presentstudy evaluated phenanthrene removal bysuspension cell cultures of two species ofFouquieriaceae, Fouquieria splendens andF. fasciculata, focusing on the effect of thepresence of this contaminant on cell viabilityand the activity of an enzymatic system.The results in both cultures showed that there was no damaging effect by phenanthrene,between 40 to 90% of which was removedby the suspension cells. The cell culturesof F. fasciculata have more phenanthreneremoval capacity compared to those of F.splendens at the different lengths of time ofexposure to the contaminant.An inductive effect of hemoperoxidaseactivity was observed simultaneously withphenanthrene removal; therefore, it ispossibly related to transformation of thecontaminant.El conocimiento del potencial metabólicode las plantas para transformar y degradarxenobióticos se ha generado a través delanálisis de la respuesta de cultivos in vitrode células vegetales expuestos ante contaminantes, ya que éstos son considerados unaherramienta útil para evaluar la fitotoxicidad, la tasa metabólica y la persistencia delos xenobióticos en las plantas.El presente estudio contempló la evaluaciónde la remoción de fenantreno en cultivos decélulas en suspensión de dos especies de lafamilia Fouquieriaceae: Fouquieria splendens y Fouquieria fasciculata y el efecto dela presencia de este contaminante a travésde la viabilidad celular y la determinaciónde la actividad de un sistema enzimático.En los cultivos de células en suspensión deambas especies, no se observó un daño por la exposición a fenantreno; la remoción delcontaminante por las células fue de un 40 a90%, siendo mayor la capacidad de remoción de fenantreno en los cultivos celularesde F. fasciculata en comparación con losde F. splendens a los diferentes tiemposa los cuales fueron expuestos estos sistemas, y paralelamente se observó un efectoinductivo sobre la actividad enzimática dehemoperoxidasas que pudieran estar relacionadas con la posible transformación delcontaminante

SSwWS: structural model of information architecture

The Web Technologies allow a representation of a domain of knowledge. This facilitates the conversion of an explicit and tacit knowledge to the possibility of adding knowledge to the Web for automatic processing by the computer. For this reason, it has been designed to be an architecture known as SSwWS (Search Semantic with Web Services) or Search Semantic Web Services, to show how to extend the functionality of the Web search and semantic raised by Berners-Lee, on the meta-references, defined in a Web ontology, so that a user on the Internet can find the answers to their questions through Web services in a simple and fast

Minding impacting events in a model of stochastic variance

We introduce a generalisation of the well-known ARCH process, widely used for generating uncorrelated stochastic time series with long-term non-Gaussian distributions and long-lasting correlations in the (instantaneous) standard deviation exhibiting a clustering profile. Specifically, inspired by the fact that in a variety of systems impacting events are hardly forgot, we split the process into two different regimes: a first one for regular periods where the average volatility of the fluctuations within a certain period of time is below a certain threshold and another one when the local standard deviation outnumbers it. In the former situation we use standard rules for heteroscedastic processes whereas in the latter case the system starts recalling past values that surpassed the threshold. Our results show that for appropriate parameter values the model is able to provide fat tailed probability density functions and strong persistence of the instantaneous variance characterised by large values of the Hurst exponent is greater than 0.8, which are ubiquitous features in complex systems.Comment: 18 pages, 5 figures, 1 table. To published in PLoS on

Ribosomal oxygenases are structurally conserved from prokaryotes to humans

2-Oxoglutarate (2OG)-dependent oxygenases have important roles in the regulation of gene expression via demethylation of N-methylated chromatin components1,2 and in the hydroxylation of transcription factors3 and splicing factor proteins4. Recently, 2OG-dependent oxygenases that catalyse hydroxylation of transfer RNA5,6,7 and ribosomal proteins8 have been shown to be important in translation relating to cellular growth, TH17-cell differentiation and translational accuracy9,10,11,12. The finding that ribosomal oxygenases (ROXs) occur in organisms ranging from prokaryotes to humans8 raises questions as to their structural and evolutionary relationships. In Escherichia coli, YcfD catalyses arginine hydroxylation in the ribosomal protein L16; in humans, MYC-induced nuclear antigen (MINA53; also known as MINA) and nucleolar protein 66 (NO66) catalyse histidine hydroxylation in the ribosomal proteins RPL27A and RPL8, respectively. The functional assignments of ROXs open therapeutic possibilities via either ROX inhibition or targeting of differentially modified ribosomes. Despite differences in the residue and protein selectivities of prokaryotic and eukaryotic ROXs, comparison of the crystal structures of E. coli YcfD and Rhodothermus marinus YcfD with those of human MINA53 and NO66 reveals highly conserved folds and novel dimerization modes defining a new structural subfamily of 2OG-dependent oxygenases. ROX structures with and without their substrates support their functional assignments as hydroxylases but not demethylases, and reveal how the subfamily has evolved to catalyse the hydroxylation of different residue side chains of ribosomal proteins. Comparison of ROX crystal structures with those of other JmjC-domain-containing hydroxylases, including the hypoxia-inducible factor asparaginyl hydroxylase FIH and histone Nε-methyl lysine demethylases, identifies branch points in 2OG-dependent oxygenase evolution and distinguishes between JmjC-containing hydroxylases and demethylases catalysing modifications of translational and transcriptional machinery. The structures reveal that new protein hydroxylation activities can evolve by changing the coordination position from which the iron-bound substrate-oxidizing species reacts. This coordination flexibility has probably contributed to the evolution of the wide range of reactions catalysed by oxygenases

Estimation of the solubility parameters of model plant surfaces and agrochemicals: a valuable tool for understanding plant surface interactions

Background Most aerial plant parts are covered with a hydrophobic lipid-rich cuticle, which is the interface between the plant organs and the surrounding environment. Plant surfaces may have a high degree of hydrophobicity because of the combined effects of surface chemistry and roughness. The physical and chemical complexity of the plant cuticle limits the development of models that explain its internal structure and interactions with surface-applied agrochemicals. In this article we introduce a thermodynamic method for estimating the solubilities of model plant surface constituents and relating them to the effects of agrochemicals. Results Following the van Krevelen and Hoftyzer method, we calculated the solubility parameters of three model plant species and eight compounds that differ in hydrophobicity and polarity. In addition, intact tissues were examined by scanning electron microscopy and the surface free energy, polarity, solubility parameter and work of adhesion of each were calculated from contact angle measurements of three liquids with different polarities. By comparing the affinities between plant surface constituents and agrochemicals derived from (a) theoretical calculations and (b) contact angle measurements we were able to distinguish the physical effect of surface roughness from the effect of the chemical nature of the epicuticular waxes. A solubility parameter model for plant surfaces is proposed on the basis of an increasing gradient from the cuticular surface towards the underlying cell wall. Conclusions The procedure enabled us to predict the interactions among agrochemicals, plant surfaces, and cuticular and cell wall components, and promises to be a useful tool for improving our understanding of biological surface interactions

Stimulation of MAP kinase pathways after maternal IL-1β exposure induces fetal lung fluid absorption in guinea pigs

BACKGROUND: We tested the hypothesis that maternal interleukin-1β (IL-1β) pretreatment and induction of fetal cortisol synthesis activates MAP kinases and thereby affects lung fluid absorption in preterm guinea pigs. METHODS: IL-1β was administered subcutaneously daily to timed-pregnant guinea pigs for three days. Fetuses were obtained by abdominal hysterotomy and instilled with isosmolar 5% albumin into the lungs and lung fluid movement was measured over 1 h by mass balance. MAP kinase expression was measured by western blot. RESULTS: Lung fluid absorption was induced at 61 days (D) gestation and stimulated at 68D gestation by IL-1β. Maternal IL-1β pretreatment upregulated ERK and upstream MEK expression at both 61 and 68D gestation, albeit being much more pronounced at 61D gestation. U0126 instillation completely blocked IL-1β-induced lung fluid absorption as well as IL-1β-induced/stimulated ERK expression. Cortisol synthesis inhibition by metyrapone attenuated ERK expression and lung fluid absorption in IL-1β-pretreated fetal lungs. JNK expression after maternal IL-1β pretreatment remained unaffected at either gestation age. CONCLUSION: These data implicate the ERK MAP kinase pathway as being important for IL-1β induction/stimulation of lung fluid absorption in fetal guinea pigs

EVALUACIÓN DE LA PROMOCIÓN DEL CRECIMIENTO DE CYNODON DACTYLON L. POR RIZOBACTERIAS PRODUCTORAS DE FITOHORMONAS AISLADAS DE UN SUELO CONTAMINADO CON HIDROCARBUROS DERIVADOS DEL PETRÓLEO

The selection of plant growth-promotingrhizobacteria (PGPR) can be based on the in vitro analysis of their auxin-producingand growth-promoting capabilities. Thisstudy determined the intrinsic productionof indole acetic acid (IAA) by rhizobacteriaisolated from petroleum-contaminated soiland tested its potential for growth promotion. The three isolated rhizobacteria (I,II and III) were high producers of indoleacetic acid in vitro. Cynodon dactylonL. was inoculated with these isolates inhydroponic systems. The Rhizobacteriumspp. strains I and II showed plant growthpromotion without the addition of Trp (acommon precursor in the biosynthesis ofIAA), whereas strain III required the addition of Trp to promote foliar developmentin C. dactylon.El analizar rizobacterias por su potencialin vitro de producción de auxinas puedeproveer de una base rentable para la selección de cepas efectivas, particularmente siesta capacidad se emplea en combinacióncon el análisis de su actividad promotoradel crecimiento. Este estudio consistió enla caracterización de la producción intrínseca de rizobacterias aisladas de un suelocontaminado con hidrocarburos derivadosdel petróleo de producir ácido indolacéticoy el efecto de éstas sobre el crecimientoin vitro de Cynodon dactylon L, inoculada con estas rizobacterias en sistemashidropónicos. Las rizobacterias aisladasI, II y III resultaron altas productoras invitro de ácido indolacético. Se evidenció también la promoción del crecimientode las plantas de Cynodon dactylon L.con la inoculación de las rizobacterias Iy II. En experimentos con la adición detriptofano al medio y la inoculación conla rizobacteria III se observó la accióndirecta de la presencia del precursor enla biosíntesis de ácido indolacético quefavoreció el desarrollo radical y foliar delas plantas