English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Two potassium (K + )-uptake systems, Trk and Kdp, are operative in  Mycobacterium tuberculosis  ( Mtb ), but the environmental factors triggering their expression have not been determined. The current study has evaluated the expression of these genes in the  Mtb  wild-type and a  trk -gene knockout strain at various stages of logarithmic growth in relation to extracellular K +  concentrations and pH. In both strains, mRNA levels of the K + -uptake encoding genes were relatively low compared to those of the housekeeping gene,  sigA , at the early- and mid-log phases, increasing during late-log. Increased gene expression coincided with decreased K +  uptake in the context of a drop in extracellular pH and sustained high extracellular K +  concentrations. In an additional series of experiments, the pH of the growth medium was manipulated by the addition of 1N HCl/NaOH. Decreasing the pH resulted in reductions in both membrane potential and K +  uptake in the setting of significant induction of genes encoding both K +  transporters. These observations are consistent with induction of the genes encoding the active K +  transporters of  Mtb  as a strategy to compensate for loss of membrane potential-driven uptake of K +  at low extracellular pH. Induction of these genes may promote survival in the acidic environments of the intracellular vacuole and granuloma.

Expression of the Genes Encoding the Trk and Kdp Potassium Transport Systems ofMycobacterium tuberculosisduring GrowthIn Vitro