C-terminal Poly-histidine Tags Alter Escherichia coli Polyphosphate Kinase Activity and Susceptibility to Inhibition.

In Escherichia coli, many environmental stressors trigger polyphosphate (polyP) synthesis by polyphosphate kinase (PPK1), including heat, nutrient restriction, toxic compounds, and osmotic imbalances. PPK1 is essential for virulence in many pathogens and has been the target of multiple screens for small molecule inhibitors that might serve as new anti-virulence drugs. However, the mechanisms by which PPK1 activity and polyP synthesis are regulated are poorly understood.

The role of nitrogen-responsive regulators in controlling inorganic polyphosphate synthesis in .

Inorganic polyphosphate (polyP) is synthesized by bacteria under stressful environmental conditions and acts by a variety of mechanisms to promote cell survival. While the kinase that synthesizes polyP (PPK, encoded by the gene) is well known, transcription is not activated by environmental stress and little is understood about how environmental stress signals lead to polyP accumulation. Previous work has shown that the transcriptional regulators DksA, RpoN (σ) and RpoE (σ) positively regulate polyP production, but not transcription, in .

Complex Responses to Hydrogen Peroxide and Hypochlorous Acid by the Probiotic Bacterium Lactobacillus reuteri.

Inflammatory diseases of the gut are associated with increased intestinal oxygen concentrations and high levels of inflammatory oxidants, including hydrogen peroxide (HO) and hypochlorous acid (HOCl), which are antimicrobial compounds produced by the innate immune system. This contributes to dysbiotic changes in the gut microbiome, including increased populations of proinflammatory enterobacteria ( and related species) and decreased levels of health-associated anaerobic and The pathways for HO and HOCl resistance in have been well studied, but little is known about how commensal and probiotic bacteria respond to inflammatory oxidants. In this work, we have characterized the transcriptomic response of the anti-inflammatory, gut-colonizing Gram-positive probiotic to both HO and HOCl.