Microbial Structure-Function Studies in

Coal-Tar Impacted Aquifers

Research Objective:

Fluorescence In-Situ Hybridizations (FISH) are being coupled with microautoradiography to quantitatively and specifically identify microbes within the overall microbial structure of the Cherokee FMGP site soils active in the uptake of key PAH compounds providing strong support of intrinsic bioremediation potential as well as detailed microbial information for improving modeling capabilities. Microautoradiography is the process by which radioactive materials incorporated into cell structures are located by exposure to photographic emulsion forming a pattern on the film corresponding to the spatial location of the radioactive compounds in the cell. Using short-term incubations of environmental samples with specific radiolabeled substrates, in this case 9-14C-phenanthrene, organisms that take in radioactive substrate and incorporate that substrate into new cell material will show positive silver grain formation in the autoradiography emulsion. By processing the samples with the FISH technique prior to microautoradiography, the specific organisms growing on 9-14C-phenanthrene can be identified taxanomically as well. When visualized under a microscope, cells on the same microscopic field can be viewed in fluorescence and transmission modes. The images can be coupled to identify structure-function relationships and enumerate total and substrate-active organisms. These results can be coupled to loss in the substrate of interest and thus can provide much more realistic substrate and organism-specific modeling parameters.

 

Preliminary Results - Cherokee FMGP source-zone soils:

Raw Image Files:

 

 

Total organisms and organisms active on 9-14C-Phenanthrene taxanomically:

 

Comparison of original site structure and post-incubation structure: