期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2005
卷号：102
期号：48
页码：17337-17341
DOI：10.1073/pnas.0506531102
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The transport of water into and out of unicellular organisms is a seemingly simple process in which water diffuses either through pores or directly across the membrane. Because of the rates at which water can theoretically diffuse, it is generally accepted that intracellular water is indistinguishable from extracellular water. Using stable isotope ratio mass spectrometry, we directly tested this assumption. Here we demonstrate that under active growth, up to 70% of the intracellular water in log-phase Escherichia coli cells was actually generated during metabolism and was isotopically distinct from extracellular water. The contribution of metabolism to intracellular water was substantially less in stationary-phase or quiescent cells.
关键词：stable isotope ; mass spectrometry ; water transport
