E. Puglisi, M.J. Cahill, P.A. Lessard, E. Capri, A.J. Sinskey, J.A. Archer, P. Boccazzi
Microb Ecol., 60(3), pp. 505-515, (2010)
We used a microarray targeting 3,524 genes to assess the transcriptional response of the actinomycete Rhodococcus aetherivorans
I24 in minimal medium supplemented with various substrates (e.g., PCBs)
and in both PCB-contaminated and non-contaminated sediment slurries.
Relative to the reference condition (minimal medium supplemented with
glucose), 408 genes were upregulated in the various treatments. In
medium and in sediment, PCBs elicited the upregulation of a common set
of 100 genes, including gene-encoding chaperones (groEL), a superoxide dismutase (sodA), alkyl hydroperoxide reductase protein C (ahpC), and a catalase/peroxidase (katG). Analysis of the R. aetherivorans
I24 genome sequence identified orthologs of many of the genes in the
canonical biphenyl pathway, but very few of these genes were upregulated
in response to PCBs or biphenyl. This study is one of the first to use
microarrays to assess the transcriptional response of a soil bacterium
to a pollutant under conditions that more closely resemble the natural
environment. Our results indicate that the transcriptional response of R. aetherivorans I24 to PCBs, in both medium and sediment, is primarily directed towards reducing oxidative stress, rather than catabolism.