Stewart Frank J, Cavanaugh Colleen M
Department of Organismic and Evolutionary Biology, The Biological Laboratories, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA.
Antonie Van Leeuwenhoek. 2006 Nov;90(4):343-60. doi: 10.1007/s10482-006-9086-6. Epub 2006 Oct 7.
Endosymbioses between chemosynthetic bacteria and marine invertebrates are remarkable biological adaptations to life in sulfide-rich environments. In these mutualistic associations, sulfur-oxidizing chemoautotrophic bacteria living directly within host cells both aid in the detoxification of toxic sulfide and fix carbon to support the metabolic needs of the host. Though best described for deep-sea vents and cold seeps, these symbioses are ubiquitous in shallow-water reducing environments. Indeed, considerable insight into sulfur-oxidizing endosymbioses in general comes from detailed studies of shallow-water protobranch clams in the genus Solemya. This review highlights the impressive body of work characterizing bacterial symbiosis in Solemya species, all of which are presumed to harbor endosymbionts. In particular, studies of the coastal Atlantic species Solemya velum and its larger Pacific congener Solemya reidi are the foundation for our understanding of the metabolism and physiology of marine bivalve symbioses, which are now known to occur in five families. Solemya velum, in particular, is an excellent model organism for symbiosis research. This clam can be collected easily from coastal eelgrass beds and maintained in laboratory aquaria for extended periods. In addition, the genome of the S. velum symbiont is currently being sequenced. The integration of genomic data with additional experimental analyses will help reveal the molecular basis of the symbiont-host interaction in Solemya, thereby complementing the wide array of research programs aimed at better understanding the diverse relationships between bacterial and eukaryotic cells.
化学合成细菌与海洋无脊椎动物之间的内共生现象是对富含硫化物环境的显著生物适应。在这些互利共生关系中，直接生活在宿主细胞内的硫氧化化能自养细菌既有助于有毒硫化物的解毒，又能固定碳以满足宿主的代谢需求。尽管这种共生现象在深海热液喷口和冷泉中最为典型，但在浅水还原环境中也普遍存在。事实上，对硫氧化内共生现象的深入了解总体上来自对浅水底栖蛤类属Solemya的详细研究。这篇综述重点介绍了一系列令人印象深刻的研究工作，这些工作描述了Solemya物种中的细菌共生现象，所有这些物种都被认为含有内共生体。特别是，对大西洋沿岸物种Solemya velum及其更大的太平洋同类物种Solemya reidi的研究，是我们理解海洋双壳类共生代谢和生理学的基础，现在已知这种共生现象存在于五个科中。特别是Solemya velum，是共生研究的优秀模式生物。这种蛤可以很容易地从沿海鳗草草床收集，并在实验室水族箱中长期饲养。此外，S. velum共生体的基因组目前正在测序。将基因组数据与其他实验分析相结合，将有助于揭示Solemya中共生体与宿主相互作用的分子基础，从而补充旨在更好理解细菌与真核细胞之间多样关系的广泛研究项目。
