Nucleic acid-based fluorescent probes in microbial ecology: application offlow cytometry

Microorganisms in natural environments have often been treated as 'black bo x' systems. Researchers have measured the inputs and outputs of the box, an d have made bulk measurements on cell behaviour. However, unravelling the d etails of the diversity and interactions that exist within these microbial populations has proven exceptionally difficult. The information gained from the black box approach has been invaluable, and has allowed models of glob al foodwebs to be generated and tested. However, there is still little info rmation about the interactions of individual microbial cells within natural populations Such studies an essential to fully understand the integrated f unctioning of ecosystems. To achieve this goal, researchers need to be able to identify individual cells within a population, enumerate them, estimate both viability and activity, and monitor changes in response to relevant p arameters. Due to the diversity, heterogeneity and numbers of cells that ma ke up these populations, these measurements require automation and speed. A t present, the use of flow cytometry in conjunction with nucleic acid probe s provides an excellent method with which to pursue such studies. (C) 2000 Elsevier Science B.V. All rights reserved.