Effects of Toxic Substances on Natural Bacterial Assemblages Determined by Means of [3H]Thymidine Incorporation
AUTOR(ES)
Riemann, Bo
RESUMO
The effects of 3,5-dichlorophenol, 2,4-dinitrophenol, and potassium dichromate on natural bacterial assemblages were examined by means of [3H]thymidine incorporation into trichloroacetic acid-insoluble material. Results from a large number of coastal marine and freshwater samples suggest the following. (i) The effects of the three toxicants included reductions in the bacterial cell number as well as changes in rates of [3H]thymidine incorporation and in [3H]thymidine incorporation per cell. The concentrations that inhibited [3H]thymidine incorporation by 50% ranged from 3 to 11 mg liter−1 for 3,5-dichlorophenol, 6 to 10 mg liter−1 for 2,4-dinitrophenol, and 21 to 123 mg liter−1 for potassium dichromate, with a tendency to higher values in bacterial assemblages from more eutrophic environments. (ii) The effects of 3,5-dichlorophenol and potassium dichromate determined by [3H]leucine incorporation into bacterial protein were similar or larger than those obtained from [3H]thymidine incorporation. (iii) Two to four hours of exposure to the toxicants was necessary before stable maximum effects were found in [3H]thymidine incorporation. (iv) Storage of natural environmental samples should be avoided, since tests with water stored for 1 to 3 days sometimes produced results different from results obtained from in situ tests. (v) The effects of 3,5-dichlorophenol, 2,4-dinitrophenol, and potassium dichromate on natural bacterial assemblages were relatively constant during periods with different growth rates in the assemblages, during various periods of the year, and between samples from freshwater and marine localities. With some precautions, [3H]thymidine incorporation can be used as a quick and sensitive method for determining the effects of toxicants on aquatic bacterial assemblages from natural environmental samples.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=183252Documentos Relacionados
- [3H]Thymidine Incorporation To Estimate Growth Rates of Anaerobic Bacterial Strains
- Underestimation of DNA Synthesis by [3H]Thymidine Incorporation in Marine Bacteria
- Experimental Evaluation of Conversion Factors for the [3H]Thymidine Incorporation Assay of Bacterial Secondary Productivity †
- Estimating Bacterioplankton Production by Measuring [3H]thymidine Incorporation in a Eutrophic Swedish Lake
- Determining [3H]Thymidine Incorporation into Bacterioplankton DNA: Improvement of the Method by DNase Treatment