Huggett Megan J, Carpizo-Ituarte Eugenio J, Nedved Brian T, Hadfield Michael G
Biol Bull. 2021 Apr;240(2):82-94. doi: 10.1086/713623. Epub 2021 Apr 14.
AbstractThe serpulid polychaete 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 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 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.
摘要
龙介虫多毛纲动物已成为研究海洋无脊椎动物附着和变态以及海洋生物污损相关过程的主要模式生物。一种包裹性的、膜状的有机初级管的快速分泌，使附着的幼虫能够牢固地附着在表面，并为其提供一个完成变态的庇护所。虽然这种管子从不钙化，但它形成了模板，钙化管在其前端由此产生。对具备附着能力和正在附着的幼虫的扫描电子显微镜和透射电子显微镜图像的检查显示，该管子由三个主要体节的表皮细胞分泌，物质可能通过幼虫角质层丰富的微绒毛运输。该管子由复杂分层的纤维材料组成，这种材料含有大量其他多毛纲动物胶原质角质层特有的氨基酸以及相关碳水化合物。依赖表面细菌生物膜来刺激该物种附着的重要性体现在初级管物质分泌时与生物膜中细菌大量产生的细胞外聚合物之间的复杂相互作用。这种关联似乎为附着的幼虫提供了与生物膜中细菌相似的附着强度，而当幼虫附着在清洁表面时，附着强度则明显较低。
