Trop-2 inhibits prostate cancer cell adhesion to fibronectin through the β1 integrin-RACK1 axis.

Trop-2 is a transmembrane glycoprotein upregulated in several human carcinomas, including prostate cancer (PrCa). Trop-2 has been suggested to regulate cell-cell adhesion, given its high homology with the other member of the Trop family, Trop-1/EpCAM, and its ability to bind the tight junction proteins claudin-1 and claudin-7. However, a role for Trop-2 in cell adhesion to the extracellular matrix has never been postulated. Here, we show for the first time that Trop-2 expression in PrCa cells correlates with their aggressiveness. Using either shRNA-mediated silencing of Trop-2 in cells that endogenously express it, or ectopic expression of Trop-2 in cells that do not express it, we show that Trop-2 inhibits PrCa cell adhesion to fibronectin (FN). In contrast, expression of another transmembrane receptor, α(v) β(5) integrin, does not affect cell adhesion to this ligand. We find that Trop-2 does not modulate either protein or activation levels of the prominent FN receptors, β(1) integrins, but acts through increasing β(1) association with the adaptor molecule RACK1 and redistribution of RACK1 to the cell membrane. As a result of Trop-2 expression, we also observe activation of Src and FAK, known to occur upon β(1) -RACK1 interaction. These enhanced Src and FAK activities are not mediated by changes in either the activity of IGF-IR, which is known to bind RACK1, or IGF-IR\u27s ability to associate with β(1) integrins. In summary, our data demonstrate that the transmembrane receptor Trop-2 is a regulator of PrCa cell adhesion to FN through activation of the β(1) integrin-RACK1-FAK-Src signaling axis

A Water Quality Investigation of Kimages Creek

Analysis of continuous monitoring water quality data (temperature, specific conductivity, depth, pH, dissolved oxygen, and turbidity) at two locations in a tidal freshwater creek (Kimages Creek) characterized seasonal variation and responses to short-term events. Supplemental water quality measurements were collected to describe longitudinal variations in the creek. There were significant differences in water quality between the two continuous monitoring stations (one tidal and unforested, the other non-tidal and forested) over varying time scales. Rain events showed increases in turbidity, depth and dissolved oxygen, and reductions in temperature, conductivity, and pH at both stations. Tides influenced the water quality at the downstream monitoring station, but there were also influences at the upstream site despite the presence of beaver impoundments. At the downstream station, changes in conductivity and pH were linked to the tidal cycle while temperature and dissolved oxygen were linked to a diel cycle but also responded to tidal influence

Projective duals to algebraic and tropical hypersurfaces

We study a tropical analogue of the projective dual variety of a hypersurface. When $X$ is a curve in $\mathbb{P}^2$ or a surface in $\mathbb{P}^3$, we provide an explicit description of $\text{Trop}(X^*)$ in terms of $\text{Trop}(X)$, as long as $\text{Trop}(X)$ is smooth and satisfies a mild genericity condition. As a consequence, when $X$ is a curve we describe the transformation of Newton polygons under projective duality, and recover classical formulas for the degree of a dual plane curve. For higher dimensional hypersurfaces $X$, we give a partial description of $\text{Trop}(X^*)$.Comment: 47 pages, 13 figures; v2 minor revisions; accepted to PLM

Le profil de l’électeur : trop de gauche? trop de droite? trop seul et trop face?

L'article fait une lecture de questionnaires préparés pour l'étude d'élections nationales au Canada, aux Etats-Unis, et en France. La lecture est faite à partir de quatre hypothèses directrices présumant une tendance, a) à voir les choses du point de vue de la norme et du groupe dominant, b) à ne pas suffisamment utiliser l'image au lieu du verbe dans la formulation des questions, c) à concentrer les questions sur le sujet interviewé au détriment des groupes de solidarité dans lesquels le sujet est inséré, et d) à présumer, à tort, que mesurer le positif d'une attitude dispense de mesurer le négatif de cette même attitude. La vérification de ces hypothèse est une invitation, sinon au mea culpa, du moins à la construction de questionaires plus équilibrés.Using a corpus of questionnaires prepared for the study of national élections in Canada, France, and the United-States, the article hypothesizes that the questions show a tendency a) to study phenomena from the point of view of the social norm and the dominant group b) to undervalue the use of images in favor of verbal formulations c) to focus too exclusively on the individual and ignore the subject's solidarity groups, and d) to présume, wrongly, that having measured the positive in an attitude dispenses with measuring the négative of that same attitude. The vérification of thèse expectations is an invitation, if not to mea culpas, at least to consider constructing more balanced questionnaires