β-Galactosidase activity of Escherichia coli under long-term starvation, alterations in temperature, and different nutrient conditions in lake water

• R. Özkanca ^[1]
  1. [1] Ondokuz Mayıs University

     Ondokuz Mayıs University

     Turquía

     
• Localización: International microbiology: official journal of the Spanish Society for Microbiology, ISSN 1139-6709, Vol. 5, Nº. 3, 2002, págs. 121-125
• Idioma: inglés
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• Resumen

  • β-Galactosidase activity of Escherichia coli was investigated in response to long-term starvation, changes in temperature and the presence of certain nutrient sources in lake water. β-Galactosidase activity decreased markedly in filtered-autoclaved lake water at 25°C and 37°C, whereas it remained almost constant at 4°C and 15°C for 60 days. Increases in β-galactosidase activity were observed in response to the following nutrient sources: glycine, serine, methionine and ammonium sulfate at 4°C; glycine and ammonium sulfate at 15°C; glycine, serine, methionine and ammonium sulfate at 30°C. Glycine addition led to an increase in β-galactosidase activity of almost five and seven orders of magnitude at 15°C and 30°C, respectively. In addition, L-methionine had the strongest influence on b-galactosidase activity, which was detected as an increase of seven and eleven ordersof magnitude at 4°C and 30°C, respectively. The effect of several amino acids and other nitrogen sources depended on the concentration of the nutrient source and the temperature. The results showed that, in lake water, long-term starvation, temperature change, and variationsin nitrogen sourcesalter β-galactosidase activity. Those effects should be taken into account when monitoring coliformsfrom the environment.