Fluorescent antibody techniques have allowed for the direct identification and enumeration of individual bacteria in environmental samples without requiring prior growth in culture media (Bahlool and Schmidt 1980, Cloete and Steyn 1988, Macario et al. 1989). The technique involves the use of specific antibodies raised against surface markers of defined pure cultures that are either labelled directly with fluorescent dye molecules or via a fluorescent secondary antibody. This approach has yielded important insights into the spatial distribution of microorganisms, but it suffers from a number of disadvantages. For example, expression of the antigen may be influenced by environmental factors; false-positive and false-negative results may be obtained due to cross-reactivity or lack of reaction; non-specific binding of antibodies may result in high levels of background fluorescence; and production of specific antibodies requires a pure culture of the organism of interest (Cloete and de Bruyn Various recombinant DNA techniques have subsequently been developed that are independent of cultivation methods (Fig. 1). These techniques provide ways of detecting and quantifying specific phylogenetic groups of microbes on 16S rDNA sequences, and relevant structural genes provide ways of monitoring microbial populations of environmental and industrial systems. In addition to these tools, a number of emerging technologies such as the use of biomarker genes are being increasingly used to monitor with great precision and accuracy the behaviour of microbes in the environment.

DOI link for Fluorescent antibody techniques have allowed for the direct identification and enumeration of individual bacteria in environmental samples without requiring prior growth in culture media (Bahlool and Schmidt 1980, Cloete and Steyn 1988, Macario et al. 1989). The technique involves the use of specific antibodies raised against surface markers of defined pure cultures that are either labelled directly with fluorescent dye molecules or via a fluorescent secondary antibody. This approach has yielded important insights into the spatial distribution of microorganisms, but it suffers from a number of disadvantages. For example, expression of the antigen may be influenced by environmental factors; false-positive and false-negative results may be obtained due to cross-reactivity or lack of reaction; non-specific binding of antibodies may result in high levels of background fluorescence; and production of specific antibodies requires a pure culture of the organism of interest (Cloete and de Bruyn Various recombinant DNA techniques have subsequently been developed that are independent of cultivation methods (Fig. 1). These techniques provide ways of detecting and quantifying specific phylogenetic groups of microbes on 16S rDNA sequences, and relevant structural genes provide ways of monitoring microbial populations of environmental and industrial systems. In addition to these tools, a number of emerging technologies such as the use of biomarker genes are being increasingly used to monitor with great precision and accuracy the behaviour of microbes in the environment.

Fluorescent antibody techniques have allowed for the direct identification and enumeration of individual bacteria in environmental samples without requiring prior growth in culture media (Bahlool and Schmidt 1980, Cloete and Steyn 1988, Macario et al. 1989). The technique involves the use of specific antibodies raised against surface markers of defined pure cultures that are either labelled directly with fluorescent dye molecules or via a fluorescent secondary antibody. This approach has yielded important insights into the spatial distribution of microorganisms, but it suffers from a number of disadvantages. For example, expression of the antigen may be influenced by environmental factors; false-positive and false-negative results may be obtained due to cross-reactivity or lack of reaction; non-specific binding of antibodies may result in high levels of background fluorescence; and production of specific antibodies requires a pure culture of the organism of interest (Cloete and de Bruyn Various recombinant DNA techniques have subsequently been developed that are independent of cultivation methods (Fig. 1). These techniques provide ways of detecting and quantifying specific phylogenetic groups of microbes on 16S rDNA sequences, and relevant structural genes provide ways of monitoring microbial populations of environmental and industrial systems. In addition to these tools, a number of emerging technologies such as the use of biomarker genes are being increasingly used to monitor with great precision and accuracy the behaviour of microbes in the environment.