The DGGE patterns from ground water with different hydrochemical characteristics are shown in Figure 2. Patterns from anoxic ground water (lane 1) are different from those obtained with oxic ground water (lane 2). Some bands were found in both samples, indicating bacterial populations that could adapt to both habitats.
In order to demonstrate temporal changes in microbial populations, DGGE patterns from surface water (river Ruhr) were recorded over a period of 6 months. Figure 3 shows changing patterns where certain species of DNA are found over a limited period of time, while others are found in all samples.
The complex DGGE patterns are further analyzed and compared by digitized gel imaging using the model GS-700 Imaging Densitometer and Multi Analyst software (Bio-Rad). DGGE patterns from surface and ground water reveal a specific and unique bacterial population depending on the hydrochemical properties. In addition DGGE patterns are used to demonstrate temporal and spatial variations in species composition. Sudden changes in DGGE patterns might indicate the introduction of harmful compounds (e.g. pesticides, heavy metals) to surface and ground water. Analysis by DGGE is also suitable for a subsequent species identification by sequencing individual bands.7
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2. Kuhlmann, B., Eschweiler, B., Kilb, B., Preu, G., Ziemann, E. and Schttler, U., Vom Wasser 89, 205-214 (1997).
3. Eschweiler, B., Kilb, B., Kuhlmann, B., Preu, G.