Study sites and their characteristics.

<p>* Average annual precipitation refers to the years 1978–2008 (Israel Meteorological Service archives). Rainfall amounts for the years 2007 and 2008 are in parentheses.</p><p>† Average monthly temperature refers to average monthly temperatures between the years 1998–2008 (IMS archives). Average monthly minimum and maximum temperatures between the years 1998–2008 are presented in parentheses.</p><p>‡ Plant biomass is the average of 12 0.6×0.6 m samples per site per year for the years 2007–2010. NPP amounts for the sampled years are in parentheses.</p><p>Study sites and their characteristics.</p

Ant Abundance along a Productivity Gradient: Addressing Two Conflicting Hypotheses

<div><p>The number of individuals within a population or community and their body size can be associated with changes in resource supply. While these relationships may provide a key to better understand the role of abiotic vs. biotic constraints in animal communities, little is known about the way size and abundance of organisms change along resource gradients. Here, we studied this interplay in ants, addressing two hypotheses with opposite predictions regarding variation in population densities along resource gradients- the ‘productivity hypothesis’ and the ‘productivity-based thinning hypothesis’. The hypotheses were tested in two functional groups of ground-dwelling ants that are directly primary consumers feeding on seeds: specialized seed-eaters and generalist species. We examined variations in colony density and foraging activity (a size measurement of the forager caste) in six ant assemblages along a steep productivity gradient in a semi-arid region, where precipitation and plant biomass vary 6-fold over a distance of 250km. An increase in the density or foraging activity of ant colonies along productivity gradients is also likely to affect competitive interactions among colonies, and consequently clinal changes in competition intensity were also examined. Ant foraging activity increased with productivity for both functional groups. However, colony density revealed opposing patterns: it increased with productivity for the specialized seed-eaters, but decreased for the generalist species. Competition intensity, evaluated by spatial partitioning of species at food baits and distribution of colonies, was uncorrelated with productivity in the specialized seed-eaters, but decreased with increasing productivity in the generalists. Our results provide support for two contrasting hypotheses regarding the effect of resource availability on the abundance of colonial organisms- the ‘productivity hypothesis’ for specialized seed-eaters and the ‘productivity-based thinning hypothesis’ for generalist species. These results also stress the importance of considering the role of functional groups in studies of community structure.</p></div

The relationship between Standardized Effect Size values of co-occurrence patterns between generalist species and mean annual precipitation in 2007 (open triangles) and 2008 (filled triangles).

<p>SES values between -1.96 and 1.96 indicate random species co-occurrence patterns in the experimental baits. Values above 1.96 and below -1.96 indicate non-random species segregation and aggregation, respectively.</p

The relationship between the standard score (Z) of Nearest Neighbor Distance and mean annual precipitation for the generalist species (a) and specialized seed eaters (b) in 2007 (open triangles) and 2008 (filled triangles, solid line).

<p>Z values between -1.96 and 1.96 indicate random distribution of colonies. Values above 1.96 and below -1.96 indicate colony segregation and aggregation, respectively.</p

Relationships between <i>colony density</i> or <i>forager number per species</i> and mean annual precipitation in 2007 (a,c) and 2008 (b,d) of the generalist species (open circles, dashed line) or both functional groups when monitored together (plus sign, solid line) in the 20 × 15 m plots.

<p>The same relationships were also obtained for the specialized seed eaters (filled circles, dotted line) in the 100 × 100 m plots in 2008 (b,d) and 2009 (a,c) and standardized according to the 20 × 15 m plots.</p

Renal Proximal Tubule Cell Cannabinoid-1 Receptor Regulates Bone Remodeling and Mass via a Kidney-to-Bone Axis

The renal proximal tubule cells (RPTCs), well-known for maintaining glucose and mineral homeostasis, play a critical role in the regulation of kidney function and bone remodeling. Deterioration in RPTC function may therefore lead to the development of diabetic kidney disease (DKD) and osteoporosis. Previously, we have shown that the cannabinoid-1 receptor (CB1R) modulates both kidney function as well as bone remodeling and mass via its direct role in RPTCs and bone cells, respectively. Here we employed genetic and pharmacological approaches that target CB1R, and found that its specific nullification in RPTCs preserves bone mass and remodeling both under normo- and hyper-glycemic conditions, and that its chronic blockade prevents the development of diabetes-induced bone loss. These protective effects of negatively targeting CB1R specifically in RPTCs were associated with its ability to modulate erythropoietin (EPO) synthesis, a hormone known to affect bone mass and remodeling. Our findings highlight a novel molecular mechanism by which CB1R in RPTCs remotely regulates skeletal homeostasis via a kidney-to-bone axis that involves EPO

From sensors to silencers: quinoline- and benzimidazole-sulfonamides as inhibitors for zinc proteases.

Derived from the extensive work in the area of small molecule zinc(II) ion sensors, chelating fragment libraries of quinoline- and benzimidazole-sulfonamides have been prepared and screened against several different zinc(II)-dependent matrix metalloproteinases (MMPs). The fragments show impressive inhibition of these metalloenzymes and preferences for different MMPs based on the nature of the chelating group. The findings show that focused chelator libraries are a powerful strategy for the discovery of lead fragments for metalloprotein inhibition

Inhibition Mechanism of Membrane Metalloprotease by an Exosite-Swiveling Conformational Antibody

SummaryMembrane type 1 metalloprotease (MT1-MMP) is a membrane-anchored, zinc-dependent protease. MT1-MMP is an important mediator of cell migration and invasion, and overexpression of this enzyme has been correlated with the malignancy of various tumor types. Therefore, modulators of MT1-MMP activity are proposed to possess therapeutic potential in numerous invasive diseases. Here we report the inhibition mode of MT1-MMP by LEM-2/15 antibody, which targets a surface epitope of MT1-MMP. Specifically, the crystal structures of Fab LEM-2/15 in complex with the MT1-MMP surface antigen suggest that conformational swiveling of the enzyme surface loop is required for effective binding and consequent inhibition of MT1-MMP activity on the cell membrane. This inhibition mechanism appears to be effective in controlling active MT1-MMP in endothelial cells and at the leading edge of migratory cancer cells

From Sensors to Silencers: Quinoline- and Benzimidazole-Sulfonamides as Inhibitors for Zinc Proteases

From Sensors to Silencers: Quinoline- and Benzimidazole-Sulfonamides as Inhibitors for Zinc Protease