(154i) Meta-Proteomics as a Tool to Study Microbial Communities: Effect of Cadmium Exposure

Microbial communities are the basis for engineered environmental bioprocesses. However, current methods, including 16S rDNA-based techniques, are incapable of providing information on the functions of the members of the community, which thus remains a black box. Microbial community proteomics has the potential to detect proteins expressed in an environment under different conditions. In this approach, a mixed culture can be viewed as a meta-organism, in which population shifts are a form of functional response. Despite its possible advantages, the use of meta-proteomics has been almost completely unexplored. In this project, meta-proteomics was used as a tool to obtain functional information about the response of a microbial community to cadmium stress. Cadmium (10 mg/L) was added to a mixed culture and protein samples collected after 0.25, 1, 2 and 3 hours. Comparison of the two-dimensional gels from Cd-exposed and control cultures revealed that the community ?reacts? by changing its protein profile, with both increased and decreased expression of substantial numbers of proteins that change with time. Mass spectrometric analysis was also performed to identify proteins that play central roles during the cadmium shock. These results clearly demonstrate the ability of the meta-proteomic approach to detect changes in microbial communities and support its use for determining functional states of a microbial community.