Project description:Using proteomics, we documented the glue composition in two congeners that live in different environments, Argiope argentata (dry southwest US) and A. trifasciata (humid southeast US). The viscoelastic protein cores of A. argentata droplets comprised a smaller portion of droplet volume than did those of A. trifasciata and, as humidity increased, incorporated a smaller percentage of absorbed water. Argiope argentata core protein was many times stiffer and tougher than A. trifasciata protein. Each species’ glue included ~30 aggregate-expressed proteins, most of which (24 and 23, respectively) were homologous between the two species. However, the relative contribution and number of gene family members of each homologous group differed. For instance, the aggregate spidroins (AgSp1 and AgSp2) accounted for nearly half of the detected glue composition in A. argentata, but only 38% in A. trifasciata. Additionally, AgSp1, which has highly negatively charged regions, was ~2X as abundant as the positively charged AgSp2 in A. argentata but ~3X as abundant in A. trifasciata. As another example, A. argentata glue included 11 members of a newly discovered cysteine-rich gene family, versus 5 in A. trifasciata. The ability to selectively express different glue protein genes and/or to extrude their products at different rates provides a faster mechanism to evolve material properties than sequence evolution alone.
Project description:Primary objectives: The primary objective is to investigate circulating tumor DNA (ctDNA) via deep sequencing for mutation detection and by whole genome sequencing for copy number analyses before start (baseline) with regorafenib and at defined time points during administration of regorafenib for treatment efficacy in colorectal cancer patients in terms of overall survival (OS).
Primary endpoints: circulating tumor DNA (ctDNA) via deep sequencing for mutation detection and by whole genome sequencing for copy number analyses before start (baseline) with regorafenib and at defined time points during administration of regorafenib for treatment efficacy in colorectal cancer patients in terms of overall survival (OS).
Project description:An orb web's prey capture thread relies on its glue droplets to retain insects until a spider can subdue them. Each droplet's viscoelastic glycoprotein adhesive core extends to dissipate the forces of prey struggle as it transfers force to stiffer, support line flagelliform fibers. In large orb webs, switchback capture thread turns are placed at the bottom of the web before a continuous capture spiral progresses from the web's periphery to its interior. To determine if the properties of capture thread droplets change during web spinning, we characterized droplet and glycoprotein volumes and material properties from the bottom, top, middle, and inner regions of webs. Both droplet and glycoprotein volume decreased during web construction, but there was a progressive increase in the glycoprotein's Young's modulus and toughness. Increases in the percentage of droplet aqueous material indicated that these increases in material properties are not due to reduced glycoprotein viscosity resulting from lower droplet hygroscopicity. Instead, they may result from changes in aqueous layer compounds that condition the glycoprotein. A 6-fold difference in glycoprotein toughness and a 70-fold difference in Young's modulus across a web documents the phenotypic plasticity of this natural adhesive and its potential to inspire new materials.