Microbial Genome Sequencing: Comparative Genomics of Chemosynthetic Symbionts

哈佛大学的Colleen Cavanaugh博士与基因组研究所的Jonathan Eisen博士合作，获得了一笔赠款，用于对两种具有代表性的化学合成细菌的基因组进行排序，这两种细菌与海洋无脊椎动物共生。就像植物中的叶绿体(产糖细胞器)一样，化学合成的共生体为宿主提供了一种内部营养来源，利用硫化物而不是阳光作为能源。化学合成菌作为尚未培养的海洋无脊椎动物的共生体和海洋环境中硫和碳循环的重要组成部分广泛存在，包括深海热液喷口。获得这些共生体基因组序列将允许与相关自由生活细菌和其他内共生体的基因组进行比较，从而提供对化学合成共生体的遗传学、代谢潜力和进化的快速洞察。这些动物-细菌共生在进化上具有重要意义，有效地创造了“吃硫动物”，并作为了解细菌起源和动物细胞器进化的模型，从生态学上讲，它们是富含硫化物环境中的初级生产者。基因组分析将回答有关微生物共生、生理学、遗传学、生态学和进化论的问题。此外，对这些基因组的比较将有助于我们理解细菌是如何在宿主世代之间传递的，以及互惠共生体与病原体之间感染机制的异同。与该项目相关的外联工作将包括通过TIGR网站提供基因组序列。该项目的网站www.endosymbiont.org包含出版物、其他基因组、研究人员、该领域新闻和教育材料的相关链接。本科生、研究生和博士后研究员将有充分的机会参与共生体基因组的分析。内生菌基因组学的信息将通过在从小学课堂到国际研究会议的各种场所的讲座向科学和普通受众传播。

A grant has been awarded to Dr. Colleen Cavanaugh of Harvard University, in collaboration with Dr. Jonathan Eisen of The Institute for Genome Research (TIGR), to sequence the genomes of two representative chemosynthetic bacteria which live in symbiotic associations with marine invertebrates. Like chloroplasts in plants (the sugar-producing organelles), chemosynthetic symbionts provide their host an internal source of nutrition, using sulfide instead of sunlight as an energy source. Chemosynthetic bacteria are widespread as symbionts of marine invertebrates, as-yet-uncultured, and substantial components of sulfur and carbon cycling in marine environments, including deep-sea hydrothermal vents. Obtaining these symbiont genome sequences will allow comparison with the genomes of related free-living bacteria and other endosymbionts, providing rapid insights into the genetics, metabolic potential, and evolution of chemosynthetic symbioses. These animal-bacteria symbioses are significant evolutionarily, effectively creating "sulfur-eating animals" and as models for understanding the bacterial origin and evolution of animal cellular organelles, and, ecologically, as primary producers in sulfide-rich environments. Genome analyses will answer questions regarding microbial symbiosis, physiology, genetics, ecology, and evolution. Further, comparison of these genomes will advance our understanding of how the bacteria are passed between host generations and the similarities and differences between infection mechanisms of mutualistic symbionts vs. pathogens. Outreach efforts associated with the project will include the availability of the genome sequences via the TIGR website. The project website, www.endosymbiont.org, contains relevant links to publications, other genomes, researchers, news in the field, and educational materials. Undergraduates, graduate students, and postdoctoral fellows will have ample opportunity to participate in analyses of the symbiont genomes. Information on endosymbiont genomics will be disseminated to scientific and general audiences by lectures at venues ranging from elementary school classes through international research meetings.