Abstract：
Microbial communities are the engines that drive the global biogeochemical cycle of carbon and nitrogen essential for life on Earth. However, microorganisms have evolved as a result of complex interactions with other organisms and environments. Deciphering the metabolism of microorganisms at the community level in nature will be crucial for a better understanding of the mechanisms that lead to the enormous divergence of microbial ecophysiology. Due to the immense number of uncultivated microbial species and the complexity of microbial communities, delineating community metabolism proves a virtually insurmountable hurdle. By tracing the heavy isotope flow of key elements such as carbon and nitrogen, DNA-based stable isotope probing (DNA-SIP) can provide unequivocal evidence for substrate assimilation by microorganisms in complex environments. The essential prerequisite for a successful DNA-SIP is the identification, with confidence, of isotopically enriched 13C-DNA, of which the amount is generally too low to allow the direct measurement of 13C atom percent of nucleic acid. The methodological considerations for obtaining unambiguous DNA highly enriched in heavy isotope are presented with emphasis on next-generation sequencing technology and metagenomics.
摘要：
微生物群落是推动地球上生命所必需的碳和氮的全球生物地球化学循环的引擎。然而,由于与其他生物体和环境的复杂相互作用，微生物已经进化。在自然界中，在群落水平上解密微生物的代谢对于更好地理解导致微生物生态生理学巨大分歧的机制至关重要。由于大量未培养的微生物物种和微生物群落的复杂性，描绘社区新陈代谢被证明是一个几乎无法克服的障碍。通过追踪碳和氮等关键元素的重同位素流动，基于DNA的稳定同位素探测（DNA-SIP）可以为复杂环境中微生物的底物同化提供明确的证据。成功的DNA-SIP的基本前提是鉴定，有信心,同位素富集的13C-DNA，的量通常太低以至于不能直接测量核酸的13C原子百分比。提出了获得高度富含重同位素的明确DNA的方法学考虑，重点是下一代测序技术和宏基因组学。
