Musat Niculina, Halm Hannah, Winterholler Bärbel, Hoppe Peter, Peduzzi Sandro, Hillion Francois, Horreard Francois, Amann Rudolf, Jørgensen Bo B, Kuypers Marcel M M
Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany.
Proc Natl Acad Sci U S A. 2008 Nov 18;105(46):17861-6. doi: 10.1073/pnas.0809329105. Epub 2008 Nov 12.
Quantitative information on the ecophysiology of individual microorganisms is generally limited because it is difficult to assign specific metabolic activities to identified single cells. Here, we develop and apply a method, Halogen In Situ Hybridization-Secondary Ion Mass Spectroscopy (HISH-SIMS), and show that it allows simultaneous phylogenetic identification and quantitation of metabolic activities of single microbial cells in the environment. Using HISH-SIMS, individual cells of the anaerobic, phototropic bacteria Chromatium okenii, Lamprocystis purpurea, and Chlorobium clathratiforme inhabiting the oligotrophic, meromictic Lake Cadagno were analyzed with respect to H(13)CO(3)(-) and (15)NH(4)(+) assimilation. Metabolic rates were found to vary greatly between individual cells of the same species, showing that microbial populations in the environment are heterogeneous, being comprised of physiologically distinct individuals. Furthermore, C. okenii, the least abundant species representing approximately 0.3% of the total cell number, contributed more than 40% of the total uptake of ammonium and 70% of the total uptake of carbon in the system, thereby emphasizing that numerically inconspicuous microbes can play a significant role in the nitrogen and carbon cycles in the environment. By introducing this quantification method for the ecophysiological roles of individual cells, our study opens a variety of possibilities of research in environmental microbiology, especially by increasing the ability to examine the ecophysiological roles of individual cells, including those of less abundant and less active microbes, and by the capacity to track not only nitrogen and carbon but also phosphorus, sulfur, and other biological element flows within microbial communities.
由于难以将特定的代谢活动归因于已鉴定的单个细胞，关于单个微生物生态生理学的定量信息通常有限。在此，我们开发并应用了一种方法，即卤素原位杂交-二次离子质谱法（HISH-SIMS），结果表明该方法能够同时对环境中单个微生物细胞进行系统发育鉴定和代谢活动定量。使用HISH-SIMS，对栖息于贫营养、半混合的卡达尼奥湖中的厌氧光合细菌奥氏着色菌、紫色灯囊菌和笼形绿菌的单个细胞进行了关于H(13)CO(3)(-)和(15)NH(4)(+)同化的分析。发现同一物种的单个细胞之间代谢率差异很大，这表明环境中的微生物种群是异质的，由生理上不同的个体组成。此外，奥氏着色菌是最不丰富的物种，约占细胞总数的0.3%，但其对系统中铵的总吸收贡献超过40%，对碳的总吸收贡献超过70%，从而强调了数量上不显眼的微生物在环境中的氮和碳循环中可以发挥重要作用。通过引入这种针对单个细胞生态生理作用的定量方法，我们的研究为环境微生物学研究开辟了多种可能性，特别是通过提高检查单个细胞（包括那些不太丰富和不太活跃的微生物）生态生理作用的能力，以及通过不仅跟踪氮和碳，还跟踪微生物群落内磷、硫和其他生物元素流动的能力。
