A Short–Time Scale Colloidal System Reveals Early Bacterial Adhesion Dynamics

The development of bacteria on abiotic surfaces has important public health and sanitary consequences. However, despite several decades of study of bacterial adhesion to inert surfaces, the biophysical mechanisms governing this process remain poorly understood, due, in particular, to the lack of methodologies covering the appropriate time scale. Using micrometric colloidal surface particles and flow cytometry analysis, we developed a rapid multiparametric approach to studying early events in adhesion of the bacterium Escherichia coli. This approach simultaneously describes the kinetics and amplitude of early steps in adhesion, changes in physicochemical surface properties within the first few seconds of adhesion, and the self-association state of attached and free-floating cells. Examination of the role of three well-characterized E. coli surface adhesion factors upon attachment to colloidal surfaces—curli fimbriae, F-conjugative pilus, and Ag43 adhesin—showed clear-cut differences in the very initial phases of surface colonization for cell-bearing surface structures, all known to promote biofilm development. Our multiparametric analysis revealed a correlation in the adhesion phase with cell-to-cell aggregation properties and demonstrated that this phenomenon amplified surface colonization once initial cell-surface attachment was achieved. Monitoring of real-time physico-chemical particle surface properties showed that surface-active molecules of bacterial origin quickly modified surface properties, providing new insight into the intricate relations connecting abiotic surface physicochemical properties and bacterial adhesion. Hence, the biophysical analytical method described here provides a new and relevant approach to quantitatively and kinetically investigating bacterial adhesion and biofilm development

Efecto del apoyo a la autonomía sobre la satisfacción académica: La motivación y el compromiso académico como variables mediadoras

Students' perceptions of the teaching practice influence their learning process. In this sense, students' perceptions of autonomy support affect various variables such as their academic satisfaction. The purpose of this study was to predict academic satisfaction of university students based on their perceptions of autonomy support, mediated by their motivation and academic engagement. The sample was made up of 637 students from the University of Cádiz and the University of Extremadura who are studying the Degrees in Primary Education and Early Childhood Education. For data collection, the Autonomy Support Scale, the State Motivation Scale, the Classroom Engagement Scale and the Academic Satisfaction Scale were administered. The data were analysed using a partial least squares structural equation modeling (PLS-SEM). The findings indicate positive effects of autonomy support on motivation, engagement and academic satisfaction; of motivation on engagement and academic satisfaction and of engagement on academic satisfaction of university students. Likewise, motivation and academic engagement have complementary mediating effects with the rest of the variables under study. Finally, through the predictive validity of the model, it is determined that it has a low out-of-sample predictive power. Recommendations are derived regarding the incorporation of strategies in teacher training that foster the autonomy of university students, thus enriching their learning process.Las percepciones del alumnado sobre la práctica docente influyen en su proceso de aprendizaje. En este sentido, las percepciones del estudiantado sobre el apoyo a la autonomía afectan a diversas variables, entre ellas su satisfacción académica. El propósito de este estudio ha sido predecir la satisfacción académica del alumnado universitario según sus percepciones sobre el apoyo a la autonomía, mediadas por su motivación y su compromiso académico. En el estudio han participado 637 estudiantes de la Universidad de Cádiz y de la Universidad de Extremadura que cursan los Grados en Educación Primaria y Educación Infantil. Para la recogida de datos, se han administrado la Escala de Apoyo a la Autonomía, la Escala de Motivación Estado, la Escala de Compromiso en el Aula y la Escala de Satisfacción Académica. Para el análisis de los datos se ha aplicado un modelo de ecuaciones estructurales de mínimos cuadrados parciales (PLS-SEM). Los hallazgos señalan efectos positivos del apoyo a la autonomía sobre la motivación, el compromiso y la satisfacción académica; de la motivación sobre el compromiso y la satisfacción académica y del compromiso sobre la satisfacción académica del alumnado universitario. Asimismo, la motivación y el compromiso académico tienen efectos mediadores complementarios con el resto de variables objeto de estudio. Finalmente, por medio de la validez predictiva del modelo, se determina que éste presenta un poder predictivo bajo fuera de la muestra. Se derivan recomendaciones para incorporar estrategias en la formación docente que promuevan la autonomía del alumnado universitario, enriqueciendo así su proceso de aprendizaje

Elevated rates of horizontal gene transfer in the industrialized human microbiome

Industrialization has impacted the human gut ecosystem, resulting in altered microbiome composition and diversity. Whether bacterial genomes may also adapt to the industrialization of their host populations remains largely unexplored. Here, we investigate the extent to which the rates and targets of horizontal gene transfer (HGT) vary across thousands of bacterial strains from 15 human populations spanning a range of industrialization. We show that HGTs have accumulated in the microbiome over recent host generations and that HGT occurs at high frequency within individuals. Comparison across human populations reveals that industrialized lifestyles are associated with higher HGT rates and that the functions of HGTs are related to the level of host industrialization. Our results suggest that gut bacteria continuously acquire new functionality based on host lifestyle and that high rates of HGT may be a recent development in human history linked to industrialization.Peer reviewe

Effect of autonomy support on academic satisfaction: academic motivation and engagement as mediating variables

Las percepciones del alumnado sobre la práctica docente influyen en su proceso de aprendizaje. En este sentido, las percepciones del estudiantado sobre el apoyo a la autonomía afectan a diversas variables, entre ellas su satisfacción académica. El propósito de este estudio ha sido predecir la satisfacción académica del alumnado universitario según sus percepciones sobre el apoyo a la autonomía, mediadas por su motivación y su compromiso académico. En el estudio han participado 637 estudiantes de la Universidad de Cádiz y de la Universidad de Extremadura que cursan los Grados en Educación Primaria y Educación Infantil. Para la recogida de datos, se han administrado la Escala de Apoyo a la Autonomía, la Escala de Motivación Estado, la Escala de Compromiso en el Aula y la Escala de Satisfacción Académica. Para el análisis de los datos se ha aplicado un modelo de ecuaciones estructurales de mínimos cuadrados parciales (PLS-SEM). Los hallazgos señalan efectos positivos del apoyo a la autonomía sobre la motivación, el compromiso y la satisfacción académica; de la motivación sobre el compromiso y la satisfacción académica y del compromiso sobre la satisfacción académica del alumnado universitario. Asimismo, la motivación y el compromiso académico tienen efectos mediadores complementarios con el resto de variables objeto de estudio. Finalmente, por medio de la validez predictiva del modelo, se determina que éste presenta un poder predictivo bajo fuera de la muestra. Se derivan recomendaciones para incorporar estrategias en la formación docente que promuevan la autonomía del alumnado universitario, enriqueciendo así su proceso de aprendizaje.Students’ perceptions of the teaching practice influence their learning process. In this sense, students’ perceptions of autonomy support affect various variables such as their academic satisfaction. The purpose of this study was to predict academic satisfaction of university students based on their perceptions of autonomy support, mediated by their motivation and academic engagement. The sample was made up of 637 students from the University of Cádiz and the University of Extremadura who are studying the Degrees in Primary Education and Early Childhood Education. For data collection, the Autonomy Support Scale, the State Motivation Scale, the Classroom Engagement Scale and the Academic Satisfaction Scale were administered. The data were analysed using a partial least squares structural equation modeling (PLS-SEM). The findings indicate positive effects of autonomy support on motivation, engagement and academic satisfaction; of motivation on engagement and academic satisfaction and of engagement on academic satisfaction of university students. Likewise, motivation and academic engagement have complementary mediating effects with the rest of the variables under study. Finally, through the predictive validity of the model, it is determined that it has a low out-of-sample predictive power. Recommendations are derived regarding the incorporation of strategies in teacher training that foster the autonomy of university students, thus enriching their learning process

LymphoAtlas: a dynamic and integrated phosphoproteomic resource of TCR signaling in primary T cells reveals ITSN 2 as a regulator of effector functions

International audienceT-cell receptor (TCR) ligation-mediated protein phosphorylation regulates the activation, cellular responses, and fates of T cells. Here, we used time-resolved high-resolution phosphoproteomics to identify, quantify, and characterize the phosphorylation dynamics of thousands of phosphorylation sites in primary T cells during the first 10 min after TCR stimulation. Bioinformatic analysis of the data revealed a coherent orchestration of biological processes underlying T-cell activation. In particular, functional modules associated with cytoskeletal remodeling, transcription, translation, and metabolic processes were mobilized within seconds after TCR engagement. Among proteins whose phosphorylation was regulated by TCR stimulation, we demonstrated, using a fast-track gene inactivation approach in primary lymphocytes, that the ITSN2 adaptor protein regulated T-cell effector functions. This resource, called LymphoAtlas, represents an integrated pipeline to further decipher the organization of the signaling network encoding T-cell activation. LymphoAtlas is accessible to the community at: https://bmm-lab. github.io/LymphoAtlas