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: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.
Project description:Sansevieria trifasciata var. laurentii (S. trifasciata) is a kind of popular in-door and out-door plant around world, it is not only known as the ornamental plant, but also as medical plant. It belongs to the Draceanaceae family, Draceanaceae includes more than 60 species distributed in tropical and subtropical dry climate regions. In this study, we sequenced the sample of S. trifasciata and determined its complete chloroplast genome. The length of CP genome is 155,179 bp, includes two invert repeats (IR) regions of 26,513 bp, a large single copy (LSC) region of 83,680 bp and a short single copy (SSC) region of 18,473 bp. There are 133 genes, which includes 87 protein coding genes, 8 rRNA and 38 tRNA, and 37.5% overall GC content. Each of trnK-UUU, rps16, trnG-UCC, atpF, rpoC1, trnL-UAA, trnV-UAC, petB, petD, rpl16, rpl2, ndhB, trnI-GAU, trnA-UGC and ndhA genes contains a intron, clpP and ycf3 contains 2 intron. The phylogenetic position shows that S. trifasciata has the closest relationship with Rohdea Chinensis (MH356725.1).
Project description:Colletotrichum sansevieriae is an ascomycete fungus causing anthracnose disease on plants in the genus Sansevieria. Here, we report the draft genome sequence of isolate Sa-1-2 of this fungus. The genome size is >51 Mb, and the assembly consists of 8647 contigs and contains 13,664 predicted protein-coding genes. Pathogenicity factors such as plant cell wall-degrading enzymes and effector proteins were also predicted. Additionally, the phylogenetic relationship of isolates from different Colletotrichum spp. was analyzed, revealing that the isolate belongs to a novel major clade consisting of species that infect succulent plants originating from Africa. The draft genome sequence has been deposited at GenBank under accession number NJHP00000000.
Project description:Spider silks combine a significant number of desirable characteristics in one material, including large tensile strength and strain at breaking, biocompatibility, and the possibility of tailoring their properties. Major ampullate gland silk (MAS) is the most studied silk and their properties are explained by a double lattice of hydrogen bonds and elastomeric protein chains linked to polyalanine β-nanocrystals. However, many basic details regarding the relationship between composition, microstructure and properties in silks are still lacking. Here we show that this relationship can be traced in flagelliform silk (Flag) spun by Argiope trifasciata spiders after identifying a phase consisting of polyglycine II nanocrystals. The presence of this phase is consistent with the dominant presence of the -GGX- and -GPG- motifs in its sequence. In contrast to the passive role assigned to polyalanine nanocrystals in MAS, polyglycine II nanocrystals can undergo growing/collapse processes that contribute to increase toughness and justify the ability of Flag to supercontract.