The Molecular Basis of Diatom Adhesion and Motility

硅藻是单细胞藻类，占全球初级生物量的约20%，因此具有巨大的生态重要性。许多硅藻具有非凡的能力，可以附着在水下任何自然和人造表面上，并通过滑行而沿着表面移动。与贻贝水下粘附的良好表征机制相反，硅藻的粘附独立于含多巴的蛋白质。硅藻产生一种含有蛋白质、富含碳水化合物的粘附物质（AM），其通过细胞壁中的专门狭缝（称为缝）分泌并沉积在基质上作为痕迹。AM提供必要的牵引力，而细胞运动的力由细胞内肌动蛋白-肌球蛋白系统产生。肌动蛋白-肌球蛋白系统被假设为通过细胞内和跨膜蛋白的连续体连接到细胞外AM尾。到目前为止，硅藻AM的分子组成和肌动蛋白-肌球蛋白为基础的运动系统的相关组件仍然很差的特点。根据我们最近的实验进展，我们的目标是在这个项目中确定的Craspedostauros australis，这是一个既定的模式生物硅藻粘附的粘附运动复合体的完整的蛋白质。该项目的工作将涉及蛋白质组学和生物信息学分析、分子遗传操作以及粘附和运动测定，以鉴定和功能表征与硅藻粘附和运动有关的蛋白质。这些结果将为硅藻水下粘附的分子基础提供新的见解，以及（B）产生使硅藻在表面上快速双向滑动的力。

Diatoms are unicellular algae that are responsible for ~20% of the global primary biomass production, and are thus of enormous ecological importance. Many diatoms have the remarkable ability to adhere to any natural and man-made surface underwater and move along the surfaces through gliding. In contrast to the well characterized mechanism for underwater adhesion of mussels, the adhesion of diatoms is independent of dopa-containing proteins. Diatoms produce a protein containing, carbohydrate-rich adhesive material (AM), which is secreted through a specialized slit in the cell wall (termed raphe) and deposited as trails on the substratum. The AM provides the necessary traction, while the force for cell motility is generated by an intracellular actin-myosin system. The actin-myosin system is hypothesized to be connected to the extracellular AM trails via a continuum of intracellular and transmembrane proteins. So far, the molecular composition of the diatom AM and the associated components of the actin-myosin based motility system has remained poorly characterized. Based our recent experimental advances we aim to identify in this project the complete set of proteins of the adhesion-motility complex in Craspedostauros australis, which is an established model organism for diatom adhesion. The work in this project will involve proteomics and bioinformatics analyses, molecular genetic manipulation, as well as adhesion and motility assays to identify and functionally characterize the proteins involved in diatom adhesion and motility. The results will provide fundamentally new insights into the molecular basis (a) for diatom underwater adhesion, and (b) for generating the force that enables the rapid bidirectional gliding of diatoms on surfaces.