Mechanisms of Vertical Transmission of Bacterial Symbionts in Marine Bivalves: Molecular Analyses of Development and Settlement

这一建议解决了海洋中最难以捉摸的问题之一， 细菌共生的模式与机制 共生体继承 我们最近的rDNA/rRNA杂交 探针研究已经证明了这些技术在以下方面的功效： 解析宿主组织内共生体靶标的低拷贝。 一 共生体传递的跨卵巢机制现在已经被 然而，在几种深海囊蛤中发现了这种细菌， 共生体整合的发展过程不能被 在这些深海代表中得到阐明。 通过初步研究， 完成后，我们建议采用类似的一套分子工具， 增加了几个新的内容来研究个体发育和 细菌共生体掺入的生化过程 原鳃双壳贝 具体而言，我们将：1） 确定共生体传播和个体发育的模式 2）将其并入鳃组织的过程， 在结合过程中共生体的代谢状态 并尽早确定共生体在宿主体内的作用 使用定量荧光显微镜进行显影，以及3） 研究共生体在环境线索检测中的作用， 通过监测关键代谢产物的表达， 共生体中的酶

This proposal addresses one of the most elusive problems in marine bacterial symbiosis research: that of the mode and mechanisms of symbiont inheritance. Our recent rDNA/rRNA-based hybridization probe studies have demonstrated the efficacy of these techniques in resolving low copies of symbiont target within host tissues. A trans-ovarial mechanism of symbiont transmission has now been identified in several species of deep-sea Vesicomyid clams, however the developmental process of symbiont incorporation cannot be elucidated in these deep-sea representatives. With initial studies completed we propose to employ a similar suite of molecular tools with several novel additions to examine the ontogenetic and biochemical process of bacterial symbiont incorporation in the protobranch bivalve Someya reidi. Specifically we will: 1) determine the mode of symbiont transmission and ontogenetic process of incorporation into the gill tissue, 2) to may the metabolic state of the symbionts during the incorporation process and determine the role of the symbionts in the hosts early development using quantitative fluorescence microscopy, and 3) to examine the symbiont role in environmental cue detection and the process of settlement by monitoring the expression of key metabolic enzymes in the symbionts.