Consistent with positive regulation by Fur , bfr mRNA levels were approximately fourfold higher in wild-type S. Typh-imurium than in a fur mutant in Fe-rich-medium .
Consistent with positive regulation by Fur , bfr mRNA levels reduced in the presence of the Fe chelator , 2,2 ′ - ( d ( d .
Consistent with positive regulation by Fur , bfr mRNA levels reduced in the presence of the Fe chelator , 2,2 ′ - ( d ( ( Fig. .
Consistent with positive regulation by Fur , bfr mRNA levels reduced in the presence of the Fe chelator , 2,2 ′ - - dipyrid ( d .
Consistent with positive regulation by Fur , bfr mRNA levels reduced in the presence of the Fe chelator , 2,2 ′ - - dipyrid ( ( Fig. .
Consistent with positive regulation by Fur , bfr mRNA levels reduced in the presence of the Fe chelator , 2,2 ′ - ( d ( d .
Consistent with positive regulation by Fur , bfr mRNA levels reduced in the presence of the Fe chelator , 2,2 ′ - ( d ( ( Fig. .
Consistent with positive regulation by Fur , bfr mRNA levels reduced in the presence of the Fe chelator , 2,2 ′ - - dipyrid ( d .
Consistent with positive regulation by Fur , bfr mRNA levels reduced in the presence of the Fe chelator , 2,2 ′ - - dipyrid ( ( Fig. .
Thus , the S. Typhimu-rium bfr are positively regulated by Fe in a Fur-dependent manner , accounting for reduced total Fe in the fur mutant .
In the absence of Fe and/or Fur , repression of ryhB is relieved , leading to negative regulation of bfr .