Arp2/3 complex from Acanthamoeba binds profilin and cross-links actin filaments

The Arp2/3 complex was first purified from Acanthamoeba castellanii by profilin affinity chromatography. The mechanism of interaction with profilin was unknown but was hypothesized to be mediated by either Arp2 or Arp3. Here we show that the Arp2 subunit of the complex can be chemically cross-linked to the actin-binding site of profilin. By analytical ultracentrifugation, rhodamine-labeled profilin binds Arp2/3 complex with a Kd of 7 microM, an affinity intermediate between the low affinity of profilin for barbed ends of actin filaments and its high affinity for actin monomers. These data suggest the barbed end of Arp2 is exposed, but Arp2 and Arp3 are not packed together in the complex exactly like two actin monomers in a filament. Arp2/3 complex also cross-links actin filaments into small bundles and isotropic networks, which are mechanically stiffer than solutions of actin filaments alone. Arp2/3 complex is concentrated at the leading edge of motile Acanthamoeba, and its localization is distinct from that of alpha-actinin, another filament cross-linking protein. Based on localization and actin filament nucleation and cross-linking activities, we propose a role for Arp2/3 in determining the structure of the actin filament network at the leading edge of motile cells.     

Are changes in blood pressure and total cholesterol related to changes in mood? An 18-month study of men and women.

The authors investigated the within-person association of reported mood with blood pressure and total cholesterol (TC) levels, each assessed 4 times over an 18-month period in 128 men and 154 women. Change over time in tense arousal was significantly positively associated with changes over time in systolic blood pressure (SBP) and diastolic blood pressure (DBP) but not TC. A change in hedonic tone was significantly associated with SBP (an increase in negative affect was associated with an increase in SBP) but not with DBP or TC. There were no sex differences in associations of mood with SBP or TC. However, increases in tense arousal and negative affect were significantly associated with an increase in DBP for women but not men. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Towards tunable polymer foam fabrication: A case study to advance green materials development in limited data scenarios

Early phases of green material development can be accelerated by identifying driving factors that control material properties to understand potential tradeoffs. Full investigation of fabrication variables is often prohibitively expensive. We propose a pared-down design of experiments (DOE) approach to identify driving variables in limited data scenarios using tunable polydimethylsiloxane (PDMS) foams made via sacrificial templating as an example system. This new approach systematically determines the dependencies of porosity, transparency, and fluid flow by varying the template particle size and packing while using a more sustainable solvent. Factor screening identified template particle size and packing density as the driving factors for foam performance by controlling pore size and interconnectivity. The framework developed provides a robust, foundational understanding of how to green and tune a novel material's properties using an efficient and effective exploration of the design space. Recommendations for applying this method to a broad suite of experiments are provided.     

I see therefore i read: improving the reading capabilities of individuals with visual disabilities through immersive virtual reality

Universal Access in the Information Society - We aim to help improve the quality of life of people with visual disabilities through the application of emerging technologies. Our current research...