The ferric uptake regulator (Fur) is a global transcription factor that regulates intracellular iron homeostasis in bacteria. The current hypothesis states that when the intracellular “free” iron concentration is elevated, Fur binds ferrous iron and the iron-bound Fur represses the genes encoding for iron uptake systems and stimulates the genes encoding for iron storage proteins. However, the “iron-bound” Fur has never been isolated from any bacteria. Here we report that the Escherichia coli Fur has a bright red color when expressed in E. coli mutant cells containing an elevated intracellular “free” iron content due to deletion of the iron-sulfur cluster assembly proteins IscA and SufA. The acid-labile iron and sulfide content analyses in conjunction with the electron paramagnetic resonance and Mössbauer spectroscopy measurements and the site-directed mutagenesis studies show that the red Fur protein binds a [2Fe-2S] cluster via conserved cysteine residues.  The occupancy of the [2Fe-2S] cluster in Fur protein is about 31% in the E. coli iscA/sufA mutant cells and is decreased to about 4% in wild-type E. coli cells. Depletion of the intracellular “free” iron content using the membrane-permeable iron chelator 2,2’-dipyridyl effectively removes the [2Fe-2S] cluster from Fur in E. coli cells, suggesting that Fur senses the intracellular “free” iron content via reversible binding of a [2Fe-2S] cluster. The binding of the [2Fe-2S] cluster in Fur appears to be highly conserved, as the Fur homolog from Haemophilus influenzae expressed in E. coli cells also reversibly binds a [2Fe-2S] cluster to sense intracellular iron homeostasis.

The linkage of patient safety and care quality to the implementation of computerized information systems assumes that clinical staff are skilled with computers. Nurses and nursing support staff increasingly require computers to carry out their work. Minimum computer competencies for nurses have been identified. The determination of whether the current nursing workforce has acquired these competencies remains uncertain. We administered a self-assessment survey to nurses and nursing support staff to determine proficiency with computer skills they might perform at work. Respondents reported inadequacies in basic and work-related computer skills. More than 28% scored themselves as having fair or poor proficiency on all skills, and more than 50% as fair or poor on five of 11 skills. Respondents over age 50 and those graduating before 1984 tended to score proficiency lower. Our study suggests that many nurses and nursing support staff may not have the minimum computer competencies to effectively and efficiently perform their work.

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