| 2. |
- Elväng, Annelie M., et al.
(författare)
-
Use of green fluorescent protein and luciferase biomarkers to monitor survival and activity of Arthrobacter chlorophenolicus A6 cells during degradation of 4-chlorophenol in soil
- 2001
-
Ingår i: Environmental Microbiology. - : Wiley. - 1462-2912 .- 1462-2920. ; 3:1, s. 32-42
-
Tidskriftsartikel (refereegranskat)abstract
- The recently isolated novel species Arthrobacter chlorophenolicus A6 is capable of growth on and degradation of high concentrations of 4-chlorophenol (up to 350 mug ml(-1)) as the sole carbon and energy source, This strain shows promise for bioremediation of environmental sites contaminated with high levels of chlorophenols. In this study, green fluorescent protein (gfp) or luciferase (luc) genes were used as biomarkers for monitoring cell number and activity, respectively, during degradation of 4-chlorophenol by A. chlorophenolicus cells. The individual marked strains, Arthrobacter chlorophenolicus A6L (luc-tagged) and Arthrobacter chlorophenolicus A6G (gfp-tagged), were monitored during degradation of 250 mug ml(-1) 4-chlorophenol in pure culture and 175 mug g(-1) 4-chlorophenol in soil microcosms. Both gene-tagged strains were capable of cleaning up the contaminated soil during 9 d incubation. During the bioremediation experiments, the luc-tagged cells were monitored using luminometry and the gfp tagged cells using flow cytometry, in addition to selective plate counting for both strains. The cells remained at high population levels in the soil (evidenced by GFP-fluorescent cell counts) and the A. chlorophenolicus A6L population was metabolically active (evidenced by luciferase activity measurements). These results demonstrate that the Arthrobacter chlorophenolicus A6 inoculum is effective for cleaning-up soil containing high concentrations of 4-chlorophenol.
|
|
| 3. |
- Jernberg, Cecilia, et al.
(författare)
-
Impact of 4-chlorophenol contamination and/or inoculation with the 4-chlorophenol-degrading strain, Arthrobacter chlorophenolicus A6L, on soil bacterial community structure
- 2002
-
Ingår i: FEMS Microbiology Ecology. - : Oxford University Press (OUP). - 0168-6496 .- 1574-6941. ; 42:3, s. 387-97
-
Tidskriftsartikel (refereegranskat)abstract
- The 4-chlorophenol-degrading strain, Arthrobacter chlorophenolicus A6L (chromosomally tagged with the firefly luciferase gene, luc) was inoculated into 4-chlorophenol-contaminated soil to assess the impact of bioaugmentation with a biodegrading strain on the indigenous microbiota. Simultaneously, the impact of 4-chlorophenol alone, or inoculation with A. chlorophenolicus into non-contaminated soil, was addressed. Using terminal restriction fragment length polymorphism (T-RFLP) several significant changes were detected in community fingerprint patterns obtained from soil microcosms treated under the different conditions. The relative abundances of some populations, as judged by the relative intensity of terminal restriction fragments, were significantly impacted by either 4-chlorophenol, A. chlorophenolicus inoculation, or by a combination of both inoculation and 4-chlorophenol contamination. Some populations were significantly stimulated and others were significantly repressed when compared to control soil with no additions. For several peaks, the positive or negative impact imposed by the treatments increased over the 13-day incubation period. Some members of the bacterial community were specifically sensitive to A. chlorophenolicus inoculation or to 4-chlorophenol contamination, whereas other populations remained relatively unaffected by any of the treatments. The A. chlorophenolicus inoculum was also monitored by T-RFLP and was found to have a significantly higher relative abundance in soil contaminated with 4-chlorophenol. These results were substantiated by a high correlation to luciferase activity measurements and the number of colony forming units of the inoculum. Therefore, the A. chlorophenolicus A6L population was positively stimulated by the presence of the 4-chlorophenol substrate (180 microg g(-1) soil) that it catabolized during the first 8 days of the incubation period as a carbon and energy source. Together, these results demonstrate that specific populations in the soil bacterial community rapidly fluctuated in response to specific disturbances and the resulting shifts in the community may therefore represent an adjustment in community structure favoring those populations best capable of responding to novel stress scenarios.
|
|
