| 11423950 |
Colores GM, Schmidt SK: Colonization of contaminated soil by an introduced bacterium: effects of initial pentachlorophenol levels on the survival of Sphingomonas chlorophenolica strain RA2. J Ind Microbiol Biotechnol. 1999 Oct;23(4-5):326-331.
The survival of a Sphingomonas species that was introduced into pentachlorophenol (PCP)-contaminated soil was monitored with two complementary methods, a respiration-based assay and a most probable number (MPN) technique. Sphingomonas chlorophenolicastrain RA2 is a PCP-mineralizing bacterium that was introduced into soil contaminated with a range of PCP concentrations (0-300 &mgr;g PCP g (-1) soil). The population of introduced microorganisms was followed for 170 days using a substrate-induced growth-response method and a MPN assay that specifically targets PCP-mineralizing bacteria. Varying the initial PCP concentration resulted in the emergence of three distinct patterns of survival. In soil contaminated with 300 &mgr;g PCP g (-1) the population of S. chlorophenolica strain RA2 immediately declined following introduction, increased by 200-fold and leveled off by the end of the 170-day incubation. In contrast, populations of S. chlorophenolica strain RA2 declined to levels below detection limits in uncontaminated soil by the end of the experiment. Intermediate PCP concentrations (10-100 &mgr;g PCP g (-1) soil) resulted in the establishment of S. chlorophenolica strain RA2 that slowly declined in numbers. These results indicate that Sphingomonas chlorophenolica strain RA2 is an effective colonizer of PCP-contaminated soil but will not persist in the absence of PCP. |
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