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:We applied high throughput sequencing technology to identify microRNA genes in bighead carp and silver carp. We identified 167 conserved miRNAs in bighead carp and 166 in silver carp. By two computational stragegies, we obtained 39 novel miRNAs in bighead carp and 54 in silver carp, for which, no homologs were found in other species. Several miRNA* sequences were found in our dataset as well, some particular ones might have gene regulation function. Gain and loss of family members were observed in several miRNA families, which partially reflected the fate of miRNA gene duplicates.
Project description:Silver-resistant Saccharomyces cerevisiae mutant was obtained by evolutionary engineering method. Briefly, genetic diversity in reference strain, CEN.PK.113-7D, was increased by ethyl methane sulfonate (EMS)-mutagenesis. The mutant population was passaged several times in gradually increasing silver stress. Several mutant individuals were selected from the final population. Among selected mutant individuals, one of them was much more resistant to silver stress than the reference strain, called as 2E. Whole-genome transcriptomic analysis was performed to identify the silver resistance mechanisms in the silver-resistant mutant strain.