A REVIEWDetection of mutagenic pollution of natural environment usingmicrobiological assaysG. We˛grzyn1,2and A. Czyz_31Department of Molecular Biology, University of Gdan´sk, Kładki, Gdan´sk, Poland,2Institute of Oceanology,Polish Academy of Sciences, S´w. Wojciecha, Gdynia, Poland, and3Laboratory of Molecular Biology (affiliatedwith the University of Gdan´sk), Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Kładki,Gdan´sk, Poland2002/0009: received 7 November 2002, revised 16 April 2003 and accepted 9 September 20031. SUMMARYOne of the most important and serious ecological problemsis mutagenic pollution of the natural environment. There-fore, detection of mutagenic compounds in samples takenfrom natural habitats is of special interest. Microbiologicalmutagenicity tests seem to be very useful tools for suchdetection. In this review article, a general view on the testsemploying genetically modified bacterial strains designed fordetection of low concentrations of mutagenic compounds ispresented. Moreover, a comparison of advantages anddisadvantages of selected assays, developed early on andmore recently, and features of these assays are discussed. Itappears that none of the currently available mutagenicitytests is perfect or optimal for all purposes. Thus, a choice forthe particular assay must depend on the nature of studiesand specific tasks of the experiments to be performed.2. THE PROBLEM OF MUTAGENICPOLLUTION OF NATURAL ENVIRONMENTMutagenic pollution of the natural environment isundoubtedly a serious and general problem. Reports ofvarious agencies indicate that the presence of mutageniccompounds in different habitats is a common phenomenonrather than an exception (see, for e.g. Davey 1999). The listof known mutagenic chemicals is very long. The Environ-mental Mutagen Information Center database (http://www.nlm.nih.gov/pubs/factsheets/emicfs.html) containsover 20 000 citations to literature on agents that have beentested for mutagenic activity. The problem of the presenceof mutagenic chemicals in natural habitats is very importantbecause such compounds are capable of inducing seriousdiseases, including cancer. Moreover, they can potentiallydamage the germ line of higher organisms, which may leadto fertility problems and to negative genetic changes infuture generations (reviewed by Mortelmans and Zeiger2000). Therefore, detection of mutagens in the naturalenvironment is very important.As chemical mutagens elicit deleterious effects on livingorganisms at extremely low concentrations, their detectionin natural habitats, at levels that can be dangerous foranimals or humans, may be difficult and complicated.Chemical methods for detection of mutagenic compoundsare expensive and time consuming. For e.g. to analyse thepresence of mutagenic compounds in a water sample,material from a few hundred litres must be concentratedbefore an actual analysis. Moreover, such methods are usefulmainly in assays for particular chemicals. As there arehundreds of different mutagenic chemicals, it is a problemwhen performing a quick and preliminary assay to deter-mine mutagenic contamination in the tested environmentalsample.1. Summary, 11752. The problem of mutagenic pollution of natural environ-ment, 11753. Biological mutagenicity assays, 11764. Using bacteria to detect mutagenes – a general view, 11765. Testing environmental samples for the presence ofmutagens, 11775.1. The Ames test, 11775.2. Mutatox, 11785.3. Vitotox, 11785.4. A newly developed Vibrio harveyi mutagenicityassay, 11796. Concluding remarks, 11797. Acknowledgements, 1180Correspondence to: Grzegorz We˛grzyn, Department of Molecular Biology,University of Gdan´sk, Kładki 24, 80-822 Gdan´sk, Poland (e-mail: [email protected]).ª 2003 The Society for Applied MicrobiologyJournal of Applied Microbiology 2003, 95, 1175–1181 doi:10.1046/j.1365-2672.2003.02121.xBiological assays may be an alternative to chemicalanalysis when detecting the presence of mutagenic com-pounds in the environment. Although no currently availablebiological test can provide detailed and precise informationabout the chemical nature of detected mutagens, such testsprovide a possibility to answer the question whetherexamined samples contain mutagens at levels potentiallydangerous for organisms. Therefore, it seems that the mostreasonable strategy for testing environmental samples is touse a biological assay as a preliminary test to detect thepresence of mutagenic compounds. Then, if necessary,subsequent detailed chemical analysis can be performed todetermine the specific type of mutagen(s).3. BIOLOGICAL MUTAGENICITY ASSAYSBiological mutagenicity assays are based on the detection ofspecific phenotypes of tester organisms that appear aftertheir contact with mutagens. Obviously, changes in pheno-types (for e.g. the ability to survive under specific condi-tions) result from changes in biochemical properties of cellsthat are caused by genetic changes. Genetic material is atarget for mutagens. Thus employing an organism whosealternative phenotypes may be easily distinguished, it ispotentially possible to determine the presence or absence ofmutagens in a tested sample on the basis of the frequency ofchanges in the specific feature of this organism. As usuallyonly one such feature is assessed, the problem of sensitivityof biological assays appears. An assay should be sensitiveenough to allow an investigator to detect levels of mutagenscapable of causing relatively low numbers of genetic changesin the whole genome. However, one phenotypic featureoften means one locus that represents a very small piece ofthe genome. Therefore, tester organisms should be signifi-cantly more sensitive to mutagenic compounds than wild-type ones.Because basic mechanisms of mutagenesis are common forall organisms, it is generally accepted that compoundscausing mutations in one type of cell should also beconsidered mutagenic for other cells. This is one of thereasons why bacteria are the most commonly used testerorganisms in mutagenicity assays. Results obtained in suchtests can be usually extrapolated to eukaryotic cells,including human cells. Furthermore, prokaryotic cells growsignificantly faster than eukaryotic cells, their cultivation issimpler and cheaper, and genetic manipulations in bacterialcells are considerably easier than in eukaryotic cells.4. USING BACTERIA TO DETECTMUTAGENS: A GENERAL VIEWMany different mutagenicity tests employing