Figure 1.
Expression ratios of the fepA gene in L. monocytogenes according to the bacterial growth phase.
BM4716 vs. BM4715 (A), and fepR deletion mutant (BM4715ΔfepR) vs. BM4715 (B).
Table 1.
MIC of antibiotics, antiseptics, and dyes against L. monocytogenes clinical isolates BM4715 and BM4716 as well as BM4715 fepR deletion mutant (BM4715ΔfepR).
Figure 2.
Schematic map of the genetic environment of fepR/fepA in L. monocytogenes BM4716 chromosome.
Open reading frames (ORFs) are indicated by horizontal arrows. Genes orf1 and orf2 putatively encode a lipase and a DNA-binding protein, respectively. The sequence corresponding to the upstream region of fepR/fepA genes is presented in details. The −35 and −10 promoter boxes are underlined and the transcription start site (TSS) is represented by an arrow. The start codon of fepR and its putative ribosome-binding site (RBS) are indicated. The non-synonymous mutation G61T (leading to substitution E21*) is shown in bold.
Figure 3.
Phylogenetic tree based on neighbor-joining analysis of sequences of bacterial efflux proteins belonging to the MATE family.
The various homologs were identified in: Aba, Acinetobacter baumannii; Bha, Bacillus halodurans; Bme, Brucella melitensis; Bth, Bacteroides thetaiotaomicron; Cdi, Clostridium difficile; Eam, Erwinia amylovora; Ecl, Enterobacter cloacae; Eco, Escherichia coli; Hin, Haemophilus influenzae; Lmo, Listeria monocytogenes; Msm, Mycobacterium smegmatis; Ngo, Neisseria gonorrhoeae; Nme, Neisseria meningitidis; Pae, Pseudomonas aeruginosa; Pfu, Pyrococcus furiosus; Rso, Ralstonia solanacearum; Sen, Salmonella enterica serovar Typhimurium; Sau, Staphylococcus aureus; Spn, Streptococcus pneumoniae; Vch, Vibrio cholerae; and Vpa, Vibrio parahaemolyticus. The scale bar represents 10% difference in amino acid sequences. Amino acid identities of each MATE protein as compared to FepA are indicated in square brackets. The two DinF and NorM subfamilies are highlighted.
Figure 4.
Agarose gel electrophoresis showing PCR products corresponding to transcripts of fepR and fepA genes.
Different sets of primers were designed to amplify specific regions of fepR (P2-F/P2-R) or fepA (P3-F/P3-R), the intergenic region (P2-F*/P3-R), the long cotranscript (P2-F/P3-R) and a negative control (P1-F/P1-R) (Table S1). Each PCR amplification was carried out on chromosomal DNA (used as positive control) and on cDNA, as indicated. MW, 1-kb ladder (New England Biolabs, France).