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

蜘蛛的惊人多样性和它们作为全球主要捕食者的角色在很大程度上可以归功于它们对丝绸的创新使用。例如，一只金色的球网蜘蛛或一只黑寡妇可以纺出六种不同类型的干纤维和湿粘着的丝绸。这些蜘蛛及其近亲(巨型蜘蛛总科蜘蛛总科)制作的湿性粘性丝绸为它们提供了更大的猎物保留力，而材料成本比其他蜘蛛群纺制的干猎物捕获丝更低。此外，这些丝胶可在各种环境中实现粘附性，包括对商用胶构成挑战的极端潮湿条件。一个来自三个机构的多学科团队将调查粘合蛋白成分的变化与胶水材料特性的变化之间的关系。18个目标品种的湿粘合丝绸在粘附性、材料效率和对湿度的响应方面存在显著差异。因此，组成蛋白质的发现将使设计具有定制性能的环境友好胶成为可能。此外，建网蜘蛛为科学教育工作者提供了许多机会，让他们在让学生融入自然世界的同时，将生物、化学、物理和数学整合在一起。研究团队将指导本科生和硕士学生，并将研究纳入本科课程。此外，团队成员将在弗吉尼亚州乡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，并指导纽约市的高中生完成原创研究项目。与其他生物粘合剂相比，蜘蛛水胶的进化多样性提供了一个独特的机会，以确定分子构建块如何对粘合的不同方面做出贡献。通过将转录组学、蛋白质组学和生物力学整合在一个系统发育框架内，拟议的实验将精确定位与界面粘连、胶内凝聚力和湿度响应性共同进化的蛋白质特征。目的1通过分析5个不同蜘蛛纲物种和3个外群分类群中每种丝腺类型的转录多样性，确定与湿粘着丝进化相关的基因表达变化。它还研究了另外13个物种在不同湿度水平下构建不同网络类型和饲料的粘合剂生产丝腺中表达水平的演变。目的2鉴定和定量组成所有18种粘附性丝绸的蛋白质以及它们的翻译后修饰。目的3测定同一18种蚕丝在不同湿度下的湿粘着丝材料性能。这些综合实验将有助于理解一项关键创新的起源和分子基础。具体地说，他们将确定制造新型丝绸所需的基因表达变化和新基因的程度。这项拟议的工作将跟踪胶蛋白特性的进化速度，包括翻译后修饰，目前人们对此知之甚少。最后，胶材料特性测量将测试这样一个假设，即蜘蛛胶滴的湿度响应性已经进化为在蜘蛛物种通常觅食的湿度下的最佳性能。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.