Identification of proteins related to the stress response in Enterococcus faecalis V583 caused by bovine bile

Abstract

BackgroundEnterococcus faecalis is an opportunistic pathogen and one of the most important causes of hospital infections. Bile acids are a major stress factor bacteria have to cope with in order to colonize and survive in the gastro-intestinal tract. The aim of this study was to investigate the effects of bile acids on the intracellular proteome of E. faecalis V583.ResultsThe proteomes of cells challenged with 1% bile were analyzed after 20 - 120 minutes exposure, using 2D gel electrophoresis and mass spectrometry. Among the approximately 500 observed proteins, 53 unique proteins were found to be regulated in response to bile and were identified with mass spectrometry. The identified proteins belonged to nine different functional classes, including fatty acid- and phospholipid-biosynthesis, energy metabolism, and transport and binding. Proteins involved in fatty acid and phospholipid biosynthesis pathways were clearly overrepresented among the identified proteins and all were down-regulated upon exposure to bile. The proteome data correlated reasonably well with data from previous transcriptome experiments done under the same conditions, but several differences were observed.ConclusionThe results provide an overview of potentially important proteins that E. faecalis V583 needs to regulate in order to survive and adapt to a bile-rich environment, among which are several proteins involved in fatty acid and phospholipid biosynthesis pathways. In addition, this study reveals several hypothetical proteins, which are both abundant and clearly regulated and thus stand out as targets for future studies on bile stress.

Transcriptional response of Enterococcus faecalis to sunlight

“…Previous research has demonstrated that environmental stressors induce transcription of multiple genes, and these genes are often similar across different stressors and different species of bacteria [11]. We compared genes found to be differentially expressed in this study to genes associated with stress response more generally in E. faecalis [22,[48][49][50][51][52][53] as well as other bacteria [11,23,24,[54][55][56]. The recombinase A gene, recA, is involved in homologous recombination, DNA repair, and known to be an important part of bacterial stress response.…”

Transcriptome, Proteome, and Metabolite Analyses of a Lactate Dehydrogenase-Negative Mutant of Enterococcus faecalis V583

“…Protein separation, gel analysis, trypsin treatment, and extraction of proteins of interest were performed as described previously (1). The gels were scanned and analyzed by Delta2D software (Decodon, Greifswald, Germany) and by a pixel-based analysis of multiple images for the identification of proteome patterns of two-dimensional (2D) gel electrophoresis images (6).…”

Incorporation of Exogenous Fatty Acids Protects Enterococcus faecalis from Membrane-Damaging Agents

“…Many efflux pumps are also linked to drug resistance (10). Studies with E. faecalis have shown that this organism alters gene expression and protein synthesis when grown in the presence of bile (11,12), and resistance to bile stress also provides cross-protection against other sources of stress (13). However, the exact mechanisms for enterococci's resistance to bile stress have not been completely elucidated.…”