Nisms to adapt to stress induced by virtually all types of ROS. One such regulator is PerR, a member of the ubiquitous Fur family of metalloregulatory repressors, which sense hydrogen peroxide. PerR uses a metal, Fe(II) or Mn(II), to activate operator DNA binding; however, PerR cannot bind Fe(II) or Mn(II) when H2O2 is present. Zn(II)-bound PerR appears to replace the Fe(II)or Mn(II)-bound species, which can lead to an increase in mrgA, katA, and ahpCF [26]. According to the speculation of Fuangthong [27] and Herbig [28], the inhibition of Mn(II) transport may be a way for cells to protect themselves. Sufficiently high concentrations of Mn(II) lead to significant PerR inhibition, which remains unaffected by the presence of peroxide. This would essentially prevent the induction of detoxification genes and limit the cell’sMechanisms of Fusaricidins to Bacillus subtilisFigure 8. Clustering analysis of 6 experiments. Six individual experiments are listed on the top of the figure, and the names of the genes are shown on the right. The similarities of the genes between the different experiments are indicated in different colors. Low expression is indicated in green; and high expression, in red. doi:10.1371/journal.pone.0050003.gability to mount a defense. However, when the Fe(II) concentration was gradually reduced, PerR activity in response to peroxide was restored. In B. subtilis, iron is transported through 3 steps: (1) threonine, glycine, and 2,3-dihydroxybenzoate are used as precursors to synthesize bacillibactin (BB) by dhbCAEBF; (2) BB is then exported from the cell by YmfE to combine with iron; and (3) Fe-BB is shuttled back into the cell via the Title Loaded From File ABC-type transporter FeuABC-YusV. To achieve intracellular iron release, Fe-BB is then hydrolyzed by the Fe-BB esterase BesA and iron is used by the cell [27]. The process of iron transport is controlled by 3 regulatory proteins: Fur, Mta, and Btr. When iron concentration is low, derepression of Fur leads 1676428 to increased activity of Mta and Btr, which accelerates BB outflow and Fe-BB uptake. In this manner, all the genes Title Loaded From File related to iron transport are upregulatedupon fusaricidin treatment of B. subtilis, robustly stimulating iron transport. We next compared our data with the results from other studies. Cluster analysis was used to determine whether other antibiotic treatments had a similar profile to that of fusaricidin. NO [28], vancomycin (Van) [18], bacitracin (Baci) [29], iron starvation [30], Fe limitation [31], and daptomycin (Dap) [32] were 24786787 all used in the comparison. As shown in Figure 8, the data from the Fe limitation treatment had the highest similarity to those from our experiment. This suggests that iron is an essential component for bacteria to resist treatment with toxins. Forty additional antibiotics were also chosen to compare with the fusaricidin treatment in this study. This comparison revealed that the treatment of B. subtilis with fusaricidin elicited a profile most similar with that of triclosan (Fig. 9).Mechanisms of Fusaricidins to Bacillus subtilisFigure 9. The clustering analysis between the antibiotic microarray data. Different antibiotics are listed on the top of the figure. The similarities of the genes between the different experiments are indicated in different colors. Low expression is indicated in green; and high expression, in red. doi:10.1371/journal.pone.0050003.gFusaricidin addition could lead B. subtilis’s membrane to be destroyed and more OH produced which a.Nisms to adapt to stress induced by virtually all types of ROS. One such regulator is PerR, a member of the ubiquitous Fur family of metalloregulatory repressors, which sense hydrogen peroxide. PerR uses a metal, Fe(II) or Mn(II), to activate operator DNA binding; however, PerR cannot bind Fe(II) or Mn(II) when H2O2 is present. Zn(II)-bound PerR appears to replace the Fe(II)or Mn(II)-bound species, which can lead to an increase in mrgA, katA, and ahpCF [26]. According to the speculation of Fuangthong [27] and Herbig [28], the inhibition of Mn(II) transport may be a way for cells to protect themselves. Sufficiently high concentrations of Mn(II) lead to significant PerR inhibition, which remains unaffected by the presence of peroxide. This would essentially prevent the induction of detoxification genes and limit the cell’sMechanisms of Fusaricidins to Bacillus subtilisFigure 8. Clustering analysis of 6 experiments. Six individual experiments are listed on the top of the figure, and the names of the genes are shown on the right. The similarities of the genes between the different experiments are indicated in different colors. Low expression is indicated in green; and high expression, in red. doi:10.1371/journal.pone.0050003.gability to mount a defense. However, when the Fe(II) concentration was gradually reduced, PerR activity in response to peroxide was restored. In B. subtilis, iron is transported through 3 steps: (1) threonine, glycine, and 2,3-dihydroxybenzoate are used as precursors to synthesize bacillibactin (BB) by dhbCAEBF; (2) BB is then exported from the cell by YmfE to combine with iron; and (3) Fe-BB is shuttled back into the cell via the ABC-type transporter FeuABC-YusV. To achieve intracellular iron release, Fe-BB is then hydrolyzed by the Fe-BB esterase BesA and iron is used by the cell [27]. The process of iron transport is controlled by 3 regulatory proteins: Fur, Mta, and Btr. When iron concentration is low, derepression of Fur leads 1676428 to increased activity of Mta and Btr, which accelerates BB outflow and Fe-BB uptake. In this manner, all the genes related to iron transport are upregulatedupon fusaricidin treatment of B. subtilis, robustly stimulating iron transport. We next compared our data with the results from other studies. Cluster analysis was used to determine whether other antibiotic treatments had a similar profile to that of fusaricidin. NO [28], vancomycin (Van) [18], bacitracin (Baci) [29], iron starvation [30], Fe limitation [31], and daptomycin (Dap) [32] were 24786787 all used in the comparison. As shown in Figure 8, the data from the Fe limitation treatment had the highest similarity to those from our experiment. This suggests that iron is an essential component for bacteria to resist treatment with toxins. Forty additional antibiotics were also chosen to compare with the fusaricidin treatment in this study. This comparison revealed that the treatment of B. subtilis with fusaricidin elicited a profile most similar with that of triclosan (Fig. 9).Mechanisms of Fusaricidins to Bacillus subtilisFigure 9. The clustering analysis between the antibiotic microarray data. Different antibiotics are listed on the top of the figure. The similarities of the genes between the different experiments are indicated in different colors. Low expression is indicated in green; and high expression, in red. doi:10.1371/journal.pone.0050003.gFusaricidin addition could lead B. subtilis’s membrane to be destroyed and more OH produced which a.
