Collaborative Research: Integrating Molecular and Material Evolution of Spider Aqueous Glues

蜘蛛的惊人多样性以及它们作为全球主要捕食者的角色在很大程度上归功于它们对丝的创新使用。例如，金球网蜘蛛或黑寡妇可以纺出六种不同类型的干纤维和一种湿粘胶丝。这些蜘蛛和它们的近亲（种类繁多的蛛科超科）制造的湿的粘胶丝比其他蜘蛛群体制造的干的猎物捕获丝花费更低，使它们能够以更低的材料留住更多的猎物。此外，这些丝胶在各种环境下都具有粘接性，包括对商用胶构成挑战的极端湿度条件。来自三个机构的多学科团队将研究粘合剂蛋白质成分的变化与胶水材料特性的变化之间的关系。18个目标种的湿粘丝在粘接性、材料效率和对湿度的响应方面存在显著差异。因此，成分蛋白的发现将允许设计具有定制特性的环保胶水。此外，造网蜘蛛为科学教育者提供了许多机会，让他们在让学生接触自然世界时，将生物学、化学、物理学和数学结合起来。研究小组将指导本科生和硕士生，并将研究纳入本科课程。此外，团队成员将在弗吉尼亚州农村公立小学开展科学丰富活动，为初中和高中科学教师举办研讨会，并指导纽约市高中生完成原创研究项目。与其他生物粘合剂相比，蜘蛛水性粘合剂的进化多样性提供了一个独特的机会，可以确定分子构建块如何促进粘附的不同方面。通过在系统发育框架内整合转录组学、蛋白质组学和生物力学，所提出的实验将查明与界面粘附、胶内内聚和湿度响应共同进化的蛋白质特征。目的1通过分析5个不同的蛛形纲物种和3个外群分类群中每种丝腺类型的转录多样性，确定与湿粘丝进化相关的基因表达变化。它还研究了另外13种在不同湿度水平下构建不同网型和觅食的粘胶产丝腺的表达水平的进化。目的2鉴定和定量组成所有18种粘丝的蛋白质，以及它们的翻译后修饰。目的3测定相同18种不同湿度下湿粘丝材料的性能。这些综合实验将有助于了解关键创新的起源和分子基础。具体来说，他们将确定基因表达变化的程度，以及制造新型丝绸所需的新基因。这项工作将追踪胶蛋白特征的进化速度，包括目前知之甚少的翻译后修饰。最后，胶水材料性能测量将检验蜘蛛胶滴的湿度响应性已经进化为蜘蛛物种典型觅食的最佳湿度性能的假设。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The spectacular diversity of spiders and their role as key predators across the globe can largely be attributed to their innovative uses of silk. For instance, a golden orb-web spider or a black widow can spin six different types of dry fibers and a wet adhesive silk. The wet adhesive silks made by these spiders and their relatives (the megadiverse superfamily Araneoidea) afford them greater prey retention for a lower material cost than the dry prey capture silk spun by other spider groups. Furthermore, these silk glues achieve adhesiveness in a wide variety of environments, including extreme humidity conditions that challenge commercial glues. A multidisciplinary team from three institutions will investigate how variation in adhesive protein components relates to variation in the glue's material properties. The wet adhesive silks of the 18 target species have significant variation in adhesiveness, material efficiency, and response to humidity. Thus, the discovery of constituent proteins will allow design of environmentally friendly glues with tailored properties. Furthermore, web-building spiders offer many opportunities for science educators to integrate biology, chemistry, physics, and mathematics as they engage their students in the natural world. The team of investigators will mentor undergraduate and Master's students, as well as incorporate the research into undergraduate course curricula. Additionally, team members will offer science enrichment activities at rural Virginia public elementary schools, run workshops for middle and high school science teachers, and mentor New York City high school students to complete original research projects.The evolutionary diversity of spider aqueous glues offers a unique opportunity compared to other bioadhesives to determine how molecular building blocks contribute to different aspects of adhesion. By integrating transcriptomics, proteomics, and biomechanics within a phylogenetic framework, the proposed experiments will pinpoint protein characteristics that co-evolve with interfacial adhesion, intra-glue cohesion, and humidity responsiveness. Objective 1 identifies shifts in gene expression associated with the evolution of wet adhesive silk by profiling transcriptional diversity in each of the silk gland types of 5 divergent araneoid species and 3 outgroup taxa. It also investigates evolution of expression levels in the adhesive-producing silk glands of an additional 13 species that build different web types and forage under divergent humidity levels. Objective 2 identifies and quantitates the proteins that compose adhesive silks of all 18 species, as well as their post-translational modifications. Objective 3 measures wet adhesive silk material properties for the same 18 species at different humidities. These integrated experiments will contribute to understanding the origin and molecular underpinnings of a key innovation. Specifically, they will determine the degree to which gene expression shifts and new genes were required to make a novel type of silk. The proposed work will track evolutionary rates in glue protein characteristics, including post-translational modifications, which is currently poorly understood. Finally, glue material property measurements will test the hypothesis that humidity responsiveness of spider glue droplets has evolved for optimal performance at the humidity in which a spider species typically forages.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.