Diversity and ecological significance of silk mechanical property plasticity in spiders.(1/3)(MOST)


Spider major ampullate (MA) silk has a combined strength and extensibility, hence toughness, superior to other biological or synthetic materials. Recent researches have shown that MA silks of some spider species exhibit physical property plasticity generated by post-secretion tailoring processes instead of by differential genetic expressions. This then is hypothesized to enable spiders to use MA silk in a variety of by ways, including in the building of webs and fine tuning of silk and web properties while facing variant environmental conditions. However, the diversity and ecological significance of silk plasticity, and mechanisms generating it at various hierarchical levels, are still far from clear. We, thus, propose to use novel and innovative research techniques to fully examine silk plasticity from ecological, nanostructural and molecular perspectives. We will use wet-stretching technique to quantify the post-secretion tailoring capacity of spiders in different functional guilds occupying different habitats and then use comparative analyses to statistically realize the ecological significance of MA silk plasticity. Wide and small angle XRD techniques associated with wet-stretching treatments will be used to measure nonostructural changes in the crystal and amorphous regions of MA silks before and after post-secretion tailoring in different spiders. Genetic methods will be performed to obtain partial MA silk gene and amino acid sequences of different spiders to reveal the molecular basis of the observed silk plasticity diversity. Finally, tensile testing and XRD techniques will be used to compare mechanical properties and nanostructures of silks reeled by different speeds to assess whether changing silk pulling speed is the mechanism use by spiders to generate silk property plasticity. Through this proposed study not only the ecological significance of spider silk plasticity diversity can be realized, the molecular basis and processing mechanisms of silk plasticity uncovered from surveying a wide array of spiders can contribute to the design of biomimetic fibers with desired properties.

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Updated: Nov-13-2020 04:47:00 (Taiwan, GMT+08:00).