A flow cell simulating a subsurface rock fracture for investigations of groundwater-derived biofilms

Laboratory scale continuous-flow-through chambers (flow cells) facilitate the observation of microbes in a controlled, fully hydrated environment, although these systems often do not simulate the environmental conditions under which microorganisms are found. We developed a flow cell that mimics a subsurface groundwater-saturated rock fracture and isamenable to confocal laser scanning microscopy while allowing for the simple removal of the attached biomass. This flow cell was used to investigate the effect of toluene, a representative contaminant for non-aqueous phase liquids, on groundwater-derived biofilms. Reduced average biofilm biomass and thickness, and diminished diversity of amplifiable 16S rRNA sequences were observed for biofilms that developed in the presence of toluene, compared to the biofilms grown in the absence of toluene. The flow cell also allowed the detection of fluorescent protein-labelled cells

L’évaluation des enseignements par les étudiants (EEE)

Cet article présente une approche de l’évaluation des enseignements par les étudiants (EEE) axée sur le soutien au développement professionnel des enseignants, qui se distingue d’une approche visant le contrôle de la qualité de l’enseignement. Une telle approche peut être mise en place ou soutenue par les centres ou services de pédagogie universitaire au sein des universités. L’article explique les principes essentiels de la mise en place d’une démarche d’EEE. L’illustration de ces principes à l’aide de trois cas propose des pistes pour la mise en place d’une démarche d’évaluation visant le soutien au développement professionnel des enseignants mais aussi des pistes de recherche à explorer.This article presents an approach to student evaluation of teaching that is oriented towards faculty professional development more than towards quality control. This approach can be implemented and supported by university centres for teaching and learning. The article explains the principles that should be considered when implementing a process of student evaluation of teaching and provides three illustrative cases. Ideas for implementing an evaluation system designed to support faculty professional development are presented along with ideas for further research on this topic.Dieser Artikel legt eine Herangehensweise über die Bewertung des Unterrichts durch die Studenten vor, die auf die Unterstützung der beruflichen Entwicklung der Professoren stützt, aber sich von einer Herangehensweise unterscheidet, die zur Qualitätskontrolle des Unterrichtens tendieren würde. Eine solche Herangehensweise kann von pädagogischen Abteilungen innerhalb der Universität eingeführt oder unterstützt werden. Der Artikel legt die wesentlichen Prinzipien zur Einführung eines Prozesses der Bewertung des Unterrichts durch die Studenten vor. Die Veranschaulichung dieser Prinzipien durch drei Studienfälle bietet Hinweise zur Einführung eines solchen Bewertungsprozesses vor, die auf die Unterstützung der beruflichen Entwicklung der Professoren abzielt, aber auch Denkanstöße für weitere Forschungen anbietet.Este artículo presenta una aproximación de la evaluación de las enseñanzas por los estudiantes (EEE) centrada en el apoyo al desarrollo profesional de los docentes, que se diferencia de una aproximación apuntando a controlar la calidad de la enseñanza. Semejante aproximación puede ser organizada o apoyada por los centros o servicios de pedagogia universitaria dentro de las universidades. El artículo explica los principios esenciales a la instalación de un proceso de EEE. La ilustración de estos principios con la ayuda de tres casos propone algunas pistas para la puesta en práctica de semejante proceso de evaluación que apunta al apoyo al desarrollo profesional de los docentes, pero también algunas pistas de investigación para explorar

Regulation of Lipogenesis by Glucocorticoids and Insulin in Human Adipose Tissue

Patients with glucocorticoid (GC) excess, Cushing's syndrome, develop a classic phenotype characterized by central obesity and insulin resistance. GCs are known to increase the release of fatty acids from adipose, by stimulating lipolysis, however, the impact of GCs on the processes that regulate lipid accumulation has not been explored. Intracellular levels of active GC are dependent upon the activity of 11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) and we have hypothesized that 11β-HSD1 activity can regulate lipid homeostasis in human adipose tissue (Chub-S7 cell line and primary cultures of human subcutaneous (sc) and omental (om) adipocytes. Across adipocyte differentiation, lipogenesis increased whilst β-oxidation decreased. GC treatment decreased lipogenesis but did not alter rates of β-oxidation in Chub-S7 cells, whilst insulin increased lipogenesis in all adipocyte cell models. Low dose Dexamethasone pre-treatment (5 nM) of Chub-S7 cells augmented the ability of insulin to stimulate lipogenesis and there was no evidence of adipose tissue insulin resistance in primary sc cells. Both cortisol and cortisone decreased lipogenesis; selective 11β-HSD1 inhibition completely abolished cortisone-mediated repression of lipogenesis. GCs have potent actions upon lipid homeostasis and these effects are dependent upon interactions with insulin. These in vitro data suggest that manipulation of GC availability through selective 11β-HSD1 inhibition modifies lipid homeostasis in human adipocytes

Globally invariant metabolism but density-diversity mismatch in springtails.

Soil life supports the functioning and biodiversity of terrestrial ecosystems. Springtails (Collembola) are among the most abundant soil arthropods regulating soil fertility and flow of energy through above- and belowground food webs. However, the global distribution of springtail diversity and density, and how these relate to energy fluxes remains unknown. Here, using a global dataset representing 2470 sites, we estimate the total soil springtail biomass at 27.5 megatons carbon, which is threefold higher than wild terrestrial vertebrates, and record peak densities up to 2 million individuals per square meter in the tundra. Despite a 20-fold biomass difference between the tundra and the tropics, springtail energy use (community metabolism) remains similar across the latitudinal gradient, owing to the changes in temperature with latitude. Neither springtail density nor community metabolism is predicted by local species richness, which is high in the tropics, but comparably high in some temperate forests and even tundra. Changes in springtail activity may emerge from latitudinal gradients in temperature, predation and resource limitation in soil communities. Contrasting relationships of biomass, diversity and activity of springtail communities with temperature suggest that climate warming will alter fundamental soil biodiversity metrics in different directions, potentially restructuring terrestrial food webs and affecting soil functioning

Global fine-resolution data on springtail abundance and community structure

Springtails (Collembola) inhabit soils from the Arctic to the Antarctic and comprise an estimated ~32% of all terrestrial arthropods on Earth. Here, we present a global, spatially-explicit database on springtail communities that includes 249,912 occurrences from 44,999 samples and 2,990 sites. These data are mainly raw sample-level records at the species level collected predominantly from private archives of the authors that were quality-controlled and taxonomically-standardised. Despite covering all continents, most of the sample-level data come from the European continent (82.5% of all samples) and represent four habitats: woodlands (57.4%), grasslands (14.0%), agrosystems (13.7%) and scrublands (9.0%). We included sampling by soil layers, and across seasons and years, representing temporal and spatial within-site variation in springtail communities. We also provided data use and sharing guidelines and R code to facilitate the use of the database by other researchers. This data paper describes a static version of the database at the publication date, but the database will be further expanded to include underrepresented regions and linked with trait data.</p

Rapid changes in shear stress induce dissociation of a Gαq/11–platelet endothelial cell adhesion molecule-1 complex

It has been recently shown that endothelial platelet endothelial cell adhesion molecule-1 (PECAM-1) expression is pro-atherogenic. PECAM-1 is involved in sensing rapid changes in fluid shear stress but the mechanisms for activating signalling complexes at the endothelial cell junction have yet to be elucidated. Additional studies suggest the activation of membrane-bound G proteins Gαq/11 also mediate flow-induced responses. Here, we investigated whether PECAM-1 and Gαq/11 could act in unison to rapidly respond to fluid shear stress. With immunohistochemistry, we observed a co-localization of Gαq/11 and PECAM-1 at the cell–cell junction in the atheroprotected section of mouse aortae. In contrast, Gαq/11 was absent from junctions in atheroprone areas as well as in all arterial sections of PECAM-1 knockout mice. In primary human endothelial cells, temporal gradients in shear stress led to a rapid dissociation of the Gαq/11–PECAM-1 complex within 30 s and a partial relocalization of the Gαq/11 staining to perinuclear areas within 150 min, whereas transitioning fluid flow devoid of temporal gradients did not disrupt the complex. Inhibition of G protein activation eliminated temporal gradient flow-induced Gαq/11–PECAM-1 dissociation. These results allow us to conclude that Gαq/11–PECAM-1 forms a mechanosensitive complex and its localization suggests the Gαq/11–PECAM-1 complex is a critical mediator of vascular diseases