Some observations on the copper tolerance of bacterial communities determined by the (H-3)-thymidine incorporation method in heavy metal polluted humus
O. Kiikkila et al., Some observations on the copper tolerance of bacterial communities determined by the (H-3)-thymidine incorporation method in heavy metal polluted humus, SOIL BIOL B, 32(6), 2000, pp. 883-885
Changes in pH after filtration of bacterial suspensions are important when
applying the radioactive thymidine incorporation method to heavy-metal poll
uted soils with low microbial activity. In the original method (Baath 1992;
Soil Biology and Biochemistry 24, 1157-1165) the blended and centrifuged s
uspension was filtered through glass wool to remove humus particles from th
e suspension. When we filtered the bacterial suspension through glass wool
the pH increased by 2 units and the thymidine incorporation rate decreased.
This made the community copper tolerance measurement ambiguous. When using
soil samples with very low activity, we recommend the use of acid-washed g
lass wool or polyester net filtration which eliminates changes in pH. (C) 2
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