Bacterial Symbionts of Hydrothermal Vent Invertebrates: Niche Characterization, Pure Culture Isolation and Fine- Scale Evolutionary Divergence

在过去10年里，加拉帕戈斯裂谷、瓜伊马斯盆地和其他地点的深海热液喷口被发现包含人口稠密、代谢活跃的动物群落。这些群落生活在永久的黑暗中，与类似的群落有高度的空间隔离，它们的食物链主要以岩石自养细菌为基础，而不是以从光区运输的产品为基础。结石自养细菌是那些氧化还原的无机化合物(如硫化氢)以产生有用能量的细菌。它们从前体二氧化碳中产生有机化合物，主要以蠕虫、蛤和贻贝组织中的共生体的形式出现在喷口。到目前为止，这些共生体中没有一种是从宿主有机体以外培养出来的。这些研究将(1)测试加拉帕戈斯喷口贻贝共生体的多种培养方法，(2)蛤类物种，(3)从广泛分离的喷口地点分离的大量管虫(Riftia Pachyptila)中完全纯化细菌DNA。通过使用DNA：DNA杂交的方法，将确定这些目前非常分离的种群之间的精细进化关系。

Within the last 10 years, deep-sea hydrothermal vents of the Galapagos Rift, Guaymas Basin and other sites have been discovered to contain densely populated, metabolically active animal communities. These communities, living in permanent darkness and having a high degree of spatial isolation from similar communities, base their food chains largely on lithoautotrophic bacteria rather than on products transported from the photic zone. Lithoautotrophic bacteria are those which oxidize reduced inorganic compounds (e.g. hydrogen sulfide) to generate useful energy. They produce organic compounds from the precursor carbon dioxide and occur at the vents principally as symbionts within tissues of worms, clams and mussels. To date none of these symbionts has been cultured apart from the host organism. These investigations will (1) test numerous approaches for cultivation of the symbiont of the Galapagos vent mussel, (2) clam species, (3) complete purification of the bacterial DNA from numerous individual tube worms (Riftia pachyptila) from widely seperated vent sites. By using the method of DNA:DNA hybridization the fine-scale evolutionary relationships between these currently very disjunct populations will be defined.