The serpulid polychaete Hydroides elegans has emerged as a major model organism for studies of marine invertebrate settlement and metamorphosis and for processes involved in marine biofouling. Rapid secretion of an enveloping, membranous, organic primary tube provides settling larvae of H. elegans firm adhesion to a surface and a refuge within which to complete metamorphosis. While this tube is never calcified, it forms the template from which the calcified tube is produced at its anterior end. Examination of scanning and transmission electron micrographs of competent and settling larvae revealed that the tube is secreted from epidermal cells of the three primary segments, with material possibly transported through the larval cuticle via abundant microvilli. The tube is composed of complexly layered fibrous material that has an abundance of the amino acids that characterize the collagenous cuticle of other polychaetes, plus associated carbohydrates. The significance of the dependence on surface bacterial biofilms for stimulating settlement in this species is revealed as a complex interaction between primary tube material, as it is secreted, and the extracellular polymeric substances abundantly produced by biofilm-residing bacteria. This association appears to provide the settling larvae with an adhesion strength similar to that of bacteria in a biofilm and significantly less when larvae settle on a clean surface.

中文翻译：

---

海洋多毛加线虫秀丽线虫的沉降和变态过程中初级管的形成和功能（Haswell，1883年）（Serpulidae）

瑟普利德多毛线虫Hydroides elegans已成为研究海洋无脊椎动物沉降和变态以及涉及海洋生物污染的过程的主要模型生物。包膜，膜状有机初级管的快速分泌提供了秀丽隐杆线虫的沉淀幼虫，其牢固粘附于表面和避难所，从而完成变态。尽管该管从未被钙化，但它形成了模板，从该模板在其前端产生钙化管。扫描感受态和沉降幼虫的扫描和透射电镜照片表明，该管是从三个主要部分的表皮细胞中分泌出来的，物质可能通过丰富的微绒毛。该试管由复杂层状的纤维材料组成，该材料具有丰富的氨基酸含量，这些氨基酸是其他多毛动物的胶原表皮的特征，另外还有相关的碳水化合物。依赖表面细菌生物膜来刺激该物种沉降的重要性被揭示为初级管材料（其被分泌）与驻留生物膜的细菌大量产生的细胞外聚合物之间的复杂相互作用。这种结合似乎为沉降的幼虫提供了与生物膜中细菌相似的粘附强度，而当幼虫沉积在干净的表面上时粘附强度大大降低。