Chemostat‐based proteomic analysis of toluene‐affected Pseudomonas putida S12

Abstract

The aim of this study was to assess the cellular response of the solvent-tolerant Pseudomonas putida S12 to toluene as the single effector. Proteomic analysis (two-dimensional difference-in-gel-electrophoresis) was used to assess the response of P. putida S12 cultured in chemostats. This approach ensures constant growth conditions, both in the presence and absence of toluene. A considerable negative effect of toluene on the cell yield was found. The need for energy in the defence against toluene was reflected by differentially expressed proteins for cell energy management. In toluene-stressed cells the balance between proton motive force (PMF) enforcing and dissipating systems was shifted. NAD(P)H generating systems were upregulated whereas the major proton-driven system, ATP synthase, was downregulated. Other differentially expressed proteins were identified: outer membrane proteins, transport proteins, stress-related proteins and translation-related proteins. In addition, a protein with no assigned function was found. This study yielded a more detailed view of the effect of toluene on the intracellular energy management of P. putida S12 and several novel leads have been obtained for further targeted investigations.

TrgI, toluene repressed gene I, a novel gene involved in toluene-tolerance in Pseudomonas putida S12

“…This confirmed that the effect of different nutrient limitations on global gene expression is larger than the effect of the presence of toluene. The residual concentration of glucose and nitrogen in the steady state cultures of P. putida S12 was similar to the previous study (Volkers et al 2006), the decrease in the biomass yield in the presence of toluene (data not shown) was comparable to earlier findings (Isken . 1999).…”

“…Our finding that the hypothetical protein PP3611 was down-regulated (Volkers et al 2006) was confirmed at the transcriptional level. We furthermore established the relationship between PP3611, renamed TrgI, and toluene tolerance and present evidence that the down-regulation of TrgI is part of the first line of defence against toluene in P. putida S12.…”

“…The aim of the present study was to gain further insight into the solvent tolerance mechanisms of P. putida S12, in addition to results from our previous proteomics study (Volkers et al 2006). Our finding that the hypothetical protein PP3611 was down-regulated (Volkers et al 2006) was confirmed at the transcriptional level.…”

“…Recently, we reported the proteomics analysis of toluene-affected chemostat-grown P. putida S12 (Volkers et al 2006). This and another recent proteomics study on P. putida DOT-T1E (Segura et al 2005) yielded valuable information with regard to the toluene response at the protein level, e.g.…”

Solvent Stress Response of the Denitrifying Bacterium “ Aromatoleum aromaticum ” Strain EbN1

“…Similarly, solvent-tolerant P. putida S12 up-regulated the OprH porin (12-fold) upon toluene stress, probably to stabilize the outer membrane (48). Furthermore, the occurrence of OmpC as several 2D electrophoresis-separated spots with different pI values, as well as molecular weights (Fig.…”