Phenotypic biomonitoring using multivariate flow cytometric analysis of multi-stained microorganisms

A new method for monitoring phenotypic profiles of pure cultures and comple x microbial communities was evaluated. Tho approach was to stain microrgani sms with a battery of fluorescent dyes prior to flow cytometry analysis (FC M) and to analyse the data using multivariate methods, including principal component analysis and pal-tial least squares. The FCM method was quantitat ively evaluated using different misrules of pure cultures as well as microb ial communities. The results showed that the method could quantitatively an d reproducibly resolve both populations and communities of microorganisms w ith 5% abundance in a diverse microbial background. Thr feasibility of moni toring complex microbiol communities over time during thr: biodegradation o f naphthalene using thr: FCM method was demonstrated. The biodegradation of naphthalene occurred to differing extents in microcosms representing three different types of aromatic-contaminated groundwater. and a sample of bio- basin water. The FCM method distinguished each of these four microbial comm unities. The phenotypic profiles were compared with genotypic profiles gene rated by random-amplified polymorphic DNA analysis. The genotypic profiles of the microbial communities: described only the microbial composition, and not their functional change, whereas the phenotypic profiles seemed to con tain information on both the composition and the functional change of the m icroorganisms. Furthermore. event analysis of the FCM data showed that micr obial communities with initially differing compositions could converge towa rds a similar composition if they had a capacity For high levels of degrada tion, whereas microbial communities with similar initial compositions could diverge if they differed ill biodegrading ability. (C) 2001 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.