Resumo

Previous proteomic analysis of Chromobacterium violaceum revealed how this bacilli gram negative bacterium utilizes its protein profile to survive under stress conditions generated by iron, hydrogen peroxide and ultraviolet-C light. In this study, we compare these proteomic data with the work of Hungria and collaborators, published in 2003, which describes all the known genes of C. violaceum related to stress tolerance revealed to date in its genome. Four interaction networks, corresponding to each proteomic experiment and the ORFs mentioned at the work of Hungria, were draw using the metasearch tool STRING 9.0 (http://string-db.org). All the networks were generated with the same attributes: low confidence index (0.150) and all prediction methods were active: Neighborhood, Gene Fusion, Co-occurrence, Co-expression, Experiments, and Databases Text mining. The assembled networks were exported and subsequently analyzed in Cytoscape 2.8.2. The networks centrality calculations were computed from local networks and topologies. The network's bottlenecks were identified through a Betweenness vs. Node Degree chart with the values generated by the CestiScaPe 1.21 plugin. We observed poor correlation between the data yielded by the proteomic analysis with the genes described at the work of Hungria in which just 23 proteins of a total of 165 mentioned were detected. We also pinpointed, through system biology tools, RpoS (RNA polymerase sigma factor S) as the main coordinator protein of stress response in C. violaceum. Although genome sequencing has a great importance, little information can be retrieved from these qualitative data. Our work shows that post genomics approaches, such as proteomics and system biology, provides a new layer of information, contributing to the understanding of biological systems.