The flagella of E. coli move the bacterium in one of two ways. When they spin counterclockwise, the cell is propelled forward in a straight line. When they spin clockwise, the bacterium tumbles in place, ultimately pointing in some new, random direction, ready for another straight-line run. The search for food is a major trigger for this tumbling and running, and the direction of flagellar spin...

A phospholipid bilayer membrane provides a selective permeability barrier that separates a cell’s world into “me” and “not me.” A large fraction of a bacterial genome is devoted to encoding proteins that allow only the desired molecules to breach this barrier and become concentrated in, or excluded from, the intracellular space. The membrane also filters information about the environment using ...

We describe a point mutation creating an additional ATG codon in the 5' untranslated region (UTR) of the HAMP gene, in a patient with juvenile hemochromatosis. By transient in vitro transfection studies, we provide evidence that the additional ATG is functional and prevents normal hepcidin production by inducing an aberrant translation initiation of the pre-hepcidin mRNA.

The Escherichia coli Aer protein contains an N-terminal PAS domain that binds flavin adenine dinucleotide (FAD), senses aerotactic stimuli, and communicates with the output signaling domain. To explore the roles of the intervening F1 and HAMP segments in Aer signaling, we isolated plasmid-borne aerotaxis-defective mutations in a host strain lacking all chemoreceptors of the methyl-accepting che...

The serine chemoreceptor of Escherichia coli contains four canonical methylation sites for sensory adaptation that lie near intersubunit helix interfaces of the Tsr homodimer. An unexplored fifth methylation site, E502, lies at an intrasubunit helix interface closest to the HAMP domain that controls input-output signaling in methyl-accepting chemotaxis proteins. We analyzed, with in vivo Förste...

We provide an appropriate comprehensive model for assessing the likely contribution of current US government programs to alleviate homeownership financial distress. In a simulation of five available mortgage distress termination options plus continuation and repayment, the HAMP program appears to foster mortgage mitigation, given our parameter value assumptions, primarily through enabling and e...