pH Sensitive surfactants from lysine: assessment of their cytotoxicity and environmental behavior

The toxicity and environmental behavior of new pH-sensitive surfactants from lysine are presented. Three different chemical structures are studied: surfactants with one amino acid and one alkyl chain, surfactants with two amino acids on the polar head and one alkyl chain, and gemini surfactants. The pH sensitivity of these compounds can be tuned by modifying their chemical structures. Cytotoxicity has been evaluated using erythrocytes and fibroblast cells. The toxic effects against these cells depend on the hydrophobicity of the molecules as well as their cationic charge density. The effect of hydrophobicity and cationic charge density on toxicity is different for each type of cells. For erythrocytes, the toxicity increases as hydrophobicity and charge density increases. Nevertheless, for fibroblasts cationic charge density affects cytotoxicity in the opposite way: the higher charge density, the lower the toxicity. The effect of the pH on hemolysis has been evaluated in detail. The aquatic toxicity was established using Daphnia magna. All surfactants yielded EC50 values considerably higher than that reported for cationic surfactants based on quaternary ammonium groups. Finally, their biodegradability was evaluated using the CO2 headspace test (ISO 14593). These lysine derivatives showed high levels of biodegradation under aerobic conditions and can be classified as"readily biodegradable compounds".

Potential impact of environmental bacteriophages in spreading antibiotic resistance genes

The idea that bacteriophage transduction plays a role in the horizontal transfer of antibiotic resistance genes is gaining momentum. Such transduction might be vital in horizontal transfer from environmental to human bodyassociated biomes and here we review many lines of evidence supporting this notion. It is well accepted that bacteriophages are the most abundant entities in most environments, where they have been shown to be quite persistent. This fact, together with the ability of many phages to infect bacteria belonging to different taxa, makes them suitable vehicles for gene transfer. Metagenomic studies confirm that substantial percentages of the bacteriophage particles present in most environments contain bacterial genes, including mobile genetic elements and antibiotic resistance genes. When specific genes of resistance to antibiotics are detected by real-time PCR in the bacteriophage populations of different environments, only tenfold lower numbers of these genes are observed, compared with those found in the corresponding bacterial populations. In addition, the antibiotic resistance genes from these bacteriophages are functional and generate resistance to the bacteria when these genes are transfected. Finally, reports about the transduction of antibiotic resistance genes are on the increase.

Growth and functionalization of carbon nanotubes on quartz filter for environmental applications

Background: Air pollution has become an important issue worldwide due to its adverse health effects. Among the different air contaminants, volatile organic compounds (VOCs) are liquids or solids with a high vapor pressure at room temperature that are extremely dangerous for human health. Removal of these compounds can be achieved using nanomaterials with tailored properties such as carbon nanotubes. Methods: Vertically-aligned multiwall carbon nanotubes (CNTs) were successfully grown on quartz filters by means of plasma enhanced chemical vapor deposition (PECVD). Furthermore, a plasma treatment was performed in order to modify the surface properties of the CNTs. The adsorption/desorption processes of three chlorinated compounds (trichloroethylene, 1,2-dichlorobenzene and chloroform) on the CNTs were studied using mass spectrometry measurements with a residual gas analyzer. Results: The adsorption capability of the CNTs increased after functionalization of their surface with a water plasma treatment. In addition, it was found that the presence of aromatic rings, water solubility and polarity of the VOCs play an important role on the adsorption/desorption kinetics at the CNTs surface. Conclusions: This study demonstrates the applicability of CNTs deposited on quartz filters for the removal or selective detection of volatile organic compounds (VOCs). The presence of aromatic rings in VOCs results in π -stacking interactions with a significant increase of their adsorption. On the other hand, it was found that CNTs surface interactions increase with water solubility and polarity of the VOC.

Minimization of biosynthetic costs in adaptive gene expression responses of yeast to environmental changes

Yeast successfully adapts to an environmental stress by altering physiology and fine-tuning metabolism. This fine-tuning is achieved through regulation of both gene expression and protein activity, and it is shaped by various physiological requirements. Such requirements impose a sustained evolutionary pressure that ultimately selects a specific gene expression profile, generating a suitable adaptive response to each environmental change. Although some of the requirements are stress specific, it is likely that others are common to various situations. We hypothesize that an evolutionary pressure for minimizing biosynthetic costs might have left signatures in the physicochemical properties of proteins whose gene expression is fine-tuned during adaptive responses. To test this hypothesis we analyze existing yeast transcriptomic data for such responses and investigate how several properties of proteins correlate to changes in gene expression. Our results reveal signatures that are consistent with a selective pressure for economy in protein synthesis during adaptive response of yeast to various types of stress. These signatures differentiate two groups of adaptive responses with respect to how cells manage expenditure in protein biosynthesis. In one group, significant trends towards downregulation of large proteins and upregulation of small ones are observed. In the other group we find no such trends. These results are consistent with resource limitation being important in the evolution of the first group of stress responses.

Crisis de las solidaridades tradicionales y nuevas formas de asociación y resistencia campesina en la Cataluña occidental (1750-1920)

El objeto de este estudio es el análisis de las solidaridades campesinas y de su crisis en la etapa final del Antiguo Régimen. A través de la Cofradía de Labradores - que, en el siglo XVIII, representaba de hecho a la mayor parte del campesinado de Lleida -, se analiza la defensa de los comunales y la lucha contra el diezmo. Estos conflictos en el fondo traducen las dificultades del pequeño campesinado de Lleida para obtener los ingresos necesarios para reproducir la unidad familiar. Se estudian las dos vías - la campesina y la de los hacendados - de desarrollo social y económico en relación con la propiedad de la tierra en la etapa de reforma liberal. Ante el fracaso de la "vía campesina", se estudia el origen del asociacionismo tanto el impulsado por el pequeño campesinado -a través de sociedades de socorros mutuos en un primer momento- como aquél que tiene como objetivo la introducción de mejoras técnico-productivas. Como en el resto de Cataluña, en la parte occidental llana se desarrollarán estas experiencias de manera más intensa en el marco de la crisis finisecular y etapa posterior.

Guerra y crisis generacional: el caso de Jean-Richard Bloch

El presente artículo trata de mostrar cómo la primera guerra mundial originó entre los intelectuales franceses un particular concepto de generación: se consideran una generación malograda, incapaz de haber podido evitar la catástrofe y, a la vez, inexperta para construir una nueva coherencia social. El análisis toma como eje principal al escritor Jean-Richard Bloch cuyas tesis son comparadas con las de sus contemporáneos con el fin de reconstruir el contexto cultural que condiciona tanto sus vidas privadas como sus trayectorias artísticas.

"Et hoc facimus propter necessitatem famis...". Possibilitats de les fonts documentals catalanes per a l'estudi de les crisis alimentàries dels segles X-XIII

European studies of famines before the thirteenth century have been based principally on chronicles and especially on information from monastic annals. These sources, which are especially numerous during the so-called Carolingian Cultural Renaissance, offer abundant evidence of a phenomenon scarcely mentioned in other types of sources, including archival sources: the frequency and gravity of crises of food supply in some regions of continental Europe during the central middle ages, an epoch which, being situated between the terrible famines of the carolingian period and the great panademics of the fourteenth century, has been considered a period “without famines.” The object of this article is to shed light on the limitations of medieval catalan chronicle sources for the reconstruction of food-supply crises which affected the catalan counties in the tenth through the thirteenth centuries and illustrate, in contrast, the multiple opportunities offered by sources from the lordly archives. A significant part of these archival sources are connected in a direct and indirect manner to the difficulties of the rural and urban populations during famines and therefore, in a broad sense, can be considered a consequence of these crises.

De la guerra de l'Empordà (1128) a la mortaldat de 1131: gènesi, extensió i extinció d'una fam. Per a una història de les crisis alimentàries a la Catalunya medieval

In the history of food shortages and subsistence crises which affected the Catalan counties during the eleventh and twelfth centuries, the famine of 1129-1131 deserves special mention. Originating in the war of 1128 involving the Empordà and neighboring counties, this famine affected the city of Barcelona and other points of Catalonia (Winter, 1131) and created conditions for the spread of a deadly epidemic (July 1130 -January 1132).

Los cambios recientes en la evolución demográfica de las áreas rurales catalanas: de la crisis al crecimiento

El estudio de las cifras que reflejan la evolución de la población y de los distintos componentes demográficos que están detrás de la misma, de cada municipio y comarca catalana en el período comprendido entre los años 1975-1996, -especialmente entre los años 1991 y 1996-, ha puesto de manifiesto que se está produciendo un cambio notable en la realidad sociodemográfica en los espacios rurales. Es un proceso que ya había sido detectado hace unos años en otros países industrializados, y cuyos factores explicativos pueden agruparse en tres ámbitos: en primer lugar, se desarrolla una transformación de las estructuras económicas de esos espacios rurales; en segundo lugar, cambia la función de dichas áreas con respecto al conjunto de la formación social catalana -cobrando un papel clave las funciones residenciales y de ocio-; y, finalmente, en tercero -en buena medida como consecuencia de los dos anteriores-, se modifican las relaciones entre las áreas urbanas y las áreas rurales, difuminándose definitivamente las barreras o fronteras entre ambas.

Molecular method for the characterization of Coxiella burnetii from clinical and environmental samples: variability of genotypes in Spain

Background: Coxiella burnetii is a highly clonal microorganism which is difficult to culture, requiring BSL3 conditions for its propagation. This leads to a scarce availability of isolates worldwide. On the other hand, published methods of characterization have delineated up to 8 different genomic groups and 36 genotypes. However, all these methodologies, with the exception of one that exhibited limited discriminatory power (3 genotypes), rely on performing between 10 and 20 PCR amplifications or sequencing long fragments of DNA, which make their direct application to clinical samples impracticable and leads to a scarce accessibility of data on the circulation of C. burnetii genotypes. Results: To assess the variability of this organism in Spain, we have developed a novel method that consists of a multiplex (8 targets) PCR and hybridization with specific probes that reproduce the previous classification of this organism into 8 genomic groups, and up to 16 genotypes. It allows for a direct haracterization from clinical and environmental samples in a single run, which will help in the study of the different genotypes circulating in wild and domestic cycles as well as from sporadic human cases and outbreaks. The method has been validated with reference isolates. A high variability of C. burnetii has been found in Spain among 90 samples tested, detecting 10 different genotypes, being those adaA negative associated with acute Q fever cases presenting as fever of intermediate duration with liver involvement and with chronic cases. Genotypes infecting humans are also found in sheep, goats, rats, wild boar and ticks, and the only genotype found in cattle has never been found among our clinical samples. Conclusions: This newly developed methodology has permitted to demonstrate that C. burnetii is highly variable in Spain. With the data presented here, cattle seem not to participate in the transmission of C. burnetii to humans in the samples studied, while sheep, goats, wild boar, rats and ticks share genotypes with the human population.

Post-market environmental monitoring of Bt maize in Spain: Non-target effects of varieties derived from the event MON810 on predatory fauna

The Spanish Government has established post-market environmental monitoring (PMEM) as mandatory for genetically modified (GM) crop varieties cultivated in Spain. In order to comply with this regulation, effects of Bt maize varieties derived from the event MON810 on the predatory fauna were monitored for two years in northeast and central Spain. The study was carried out with a randomized block design in maize fields of 3-4 ha on which the abundance of plant-dwelling predators and the activity-density of soil-dwelling predators in Bt vs. non-Bt near-isogenic varieties were compared. To this end, the plots were sampled by visual inspection of a certain number of plants and pitfall traps 6 or 7 times throughout two seasons. No significant differences in predator densities on plants were found between Bt and non-Bt varieties. In the pitfall traps, significant differences between the two types of maize were found only in Staphylinidae, in which trap catches in non-Bt maize were higher than in Bt maize in central Spain. Based on the statistical power of the assays, surrogate arthropods for PMEM purposes are proposed; Orius spp. and Araneae for visual sampling and Carabidae, Araneae, and Staphylinidae for pitfall trapping. The other predator groups recorded in the study, Nabis sp. and Coccinellidae in visual sampling and Dermaptera in pitfall trapping, gave very poor power results. To help to establish a standardized protocol for PMEM of genetically modified crops, the effect-detecting capacity with a power of 0.8 of each predator group is given.

Situación de la empresa familiar respecto a la no familiar en el sector turístico de la provincia de Lleida en un contexto de crisis

Lo que se pretende con este trabajo es localizar, presentar, y analizar, las diferencias entre empresas familiares y no familiares, tanto en lo que se refiere a su implantació, características, y funcionamiento, en el sector turístico de la provincia de Lleida. Con esta finalidad se ha analizado un muestra de 234 empresas del sector, su menor dimensión en relación a la empresa no familiar, o los distintos objetivos que una y otra empresa persiguen.

Impacte de la fisioteràpia respiratòria en la prevenció de noves crisis en pacients pediàtrics amb asma.

Introducció: La contaminació ambiental, l’estrès de vida que és porta actualment i l’abús de fàrmacs són motius pels quals patologies respiratòries com l’asma estiguin en augment. Una de les conseqüències més rellevants en els nens amb asma es l’absentisme escolar i la disminució de qualitat de vida. Característiques importants de la fisioteràpia respiratòria són prevenir i disminuir aquestes conseqüències. Objectiu: Conèixer si hi ha una disminució, al mateix temps que una prevenció del nombre de crisis respiratòries, ocasionades per l’asma, en nens de 6 a 10 anys en les escoles de la comarca del Segrià, concretament Lleida, gràcies a la fisioteràpia respiratòria. Material i mètodes: és tracta d’una investigació experimental, concretament un assaig clínic controlat i aleatori, realitzat a un grup de nens amb asma, amb edats compreses entre 6 i 10 anys. És separen en grup d’estudi i grup control, anomenat grup A i grup B, on l’observador no sabrà quin tractament es fa a cada grup. Els dos grups estan sotmesos a una educació sanitària sobre la patologia i control de constants i el grup d’estudi, anomenat B, a més a més un tractament de fisioteràpia respiratòria. El rol principal dels metges i dels fisioterapeutes serà el realitzar un tractament a cada grup, i el dels becaris recollir les dades i revisar que l’observador les passi a la base de dades de forma correcta. Conclusions: és vol aconseguir una millora significativa de la qualitat de vida i del volum respiratori ,en els dos grups, juntament amb una disminució de les crisis asmàtiques en el grup d’estudi.