Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA.
Department of Life Sciences, Texas A&M University - Corpus Christi, Corpus Christi, TX, USA.
Environ Microbiol Rep. 2017 Oct;9(5):528-536. doi: 10.1111/1758-2229.12578. Epub 2017 Sep 19.
Microbial life in the deep subsurface biosphere is taxonomically and metabolically diverse, but it is vigorously debated whether the resident organisms are thriving (metabolizing, maintaining cellular integrity and expressing division genes) or just surviving. As part of Integrated Ocean Drilling Program Expedition 347: Baltic Sea Paleoenvironment, we extracted and sequenced RNA from organic carbon-rich, nutrient-replete and permanently anoxic sediment. In stark contrast to the oligotrophic subsurface biosphere, Baltic Sea Basin samples provided a unique opportunity to understand the balance between metabolism and other cellular processes. Targeted sequencing of 16S rRNA transcripts showed Atribacteria (an uncultured phylum) and Chloroflexi to be among the dominant and the active members of the community. Metatranscriptomic analysis identified methane cycling, sulfur cycling and halogenated compound utilization as active in situ respiratory metabolisms. Genes for cellular maintenance, cellular division, motility and antimicrobial production were also transcribed. This indicates that microbial life in deep subsurface Baltic Sea Basin sediments was not only alive, but thriving.
深海地下生物圈中的微生物在分类学和代谢上是多种多样的，但人们激烈争论的是，居住在那里的生物是在茁壮成长（代谢、保持细胞完整性和表达分裂基因）还是仅仅在存活。作为综合大洋钻探计划 347 号考察：波罗的海古环境的一部分，我们从富含有机碳、营养充足且永久缺氧的沉积物中提取并测序了 RNA。与贫营养的深海地下生物圈形成鲜明对比的是，波罗的海盆地的样本为了解代谢与其他细胞过程之间的平衡提供了一个独特的机会。16S rRNA 转录本的靶向测序表明，放线菌（一个未培养的门）和绿弯菌门是群落中的主要和活跃成员。代谢组学分析确定甲烷循环、硫循环和卤代化合物利用是活跃的原位呼吸代谢。细胞维持、细胞分裂、运动和抗菌产物的基因也被转录。这表明，深海波罗的海盆地沉积物中的微生物生命不仅存活，而且茁壮成长。
