Transcription factor TnrA inhibits the biosynthetic activity of glutamine synthetase in Bacillus subtilis.

The Bacillus subtilis glutamine synthetase (GS) plays a dual role in cell metabolism by functioning as catalyst and regulator. GS catalyses the ATP-dependent synthesis of glutamine from glutamate and ammonium. Under nitrogen-rich conditions, GS becomes feedback-inhibited by high intracellular glutamine levels and then binds transcription factors GlnR and TnrA, which control the genes of nitrogen assimilation.

Interaction of the membrane-bound GlnK-AmtB complex with the master regulator of nitrogen metabolism TnrA in Bacillus subtilis.

PII proteins are widespread and highly conserved signal transduction proteins occurring in bacteria, Archaea, and plants and play pivotal roles in controlling nitrogen assimilatory metabolism. This study reports on biochemical properties of the PII-homologue GlnK (originally termed NrgB) in Bacillus subtilis (BsGlnK). Like other PII proteins, the native BsGlnK protein has a trimeric structure and readily binds ATP in the absence of divalent cations, whereas 2-oxoglutarate is only weakly bound.

Inhaled iloprost reverses vascular remodeling in chronic experimental pulmonary hypertension.

Rationale: Inhaled iloprost is an effective therapy for pulmonary arterial hypertension (PAH). However, no study to date has addressed the effects of inhaled iloprost on changes to pulmonary vascular structure that occur in PAH.

Objectives: The present study was designed to investigate chronic antiremodeling effects of inhaled iloprost in monocrotaline (MCT)-induced PAH in rats.