Proteomic studies in Acidthiobacillus ferrooxidans cells induced by synthetic acyl-homoserine lactones

摘要

Quorum sensing (QS) is a widespread phenomenon that enables bacterial cells to establish cell-to-cell communication and to regulate the expression of specific genes in response to local changes in cell density. In Gram-negative bacteria the signal molecules used for this cell-cell communication, frequently referred to as autoinducers (AI), are mainly N-acyl homoserine lactones (AHLs). A. ferrooxidans was the first acidophilic chemolithotrophic γ-proteobacteria involved in biomining in which a functional QS system has been identified (Farah et. al., 2005, Appl. Environ. Microbiol. 71:7033-40). Analysis of culture supernatants revealed that A. ferrooxidans produce nine different kinds of AHLs. This microorganism develops biofilm structures on mineral surfaces which are essential for the bioleaching process. As in many bacteria QS regulates the biofilm formation, we decided to study the proteomic changes of A. ferroxidans cells induced by synthetic AHLs and grown in different energetic substrates to identify proteins whose expression are regulated by this QS system. The proteomic studies were made by 2D-PAGE assisted by computational analysis with the Delta 2D software. Preliminary results revealed changes in respect to the control condition without AHL induction. The amino-terminal sequence identifications of these proteins is currently in progress and should allow us to understand which physiological function (s) is (are) controlled by QS in A. ferrooxidans and if biofilm production is one of them.