[Generation of proton motive force (Delta mu H+) in Neisseria gonorrhoeae cells]

Area of Science:

• Microbiology
• Cellular Physiology
• Biochemistry

Background:

• Neisseria gonorrhoeae (gonococci) are significant human pathogens.
• Understanding their energy metabolism is crucial for developing new therapeutic strategies.
• Proton motive force (PMF) is a key indicator of cellular energy status.

Purpose of the Study:

• To investigate the components and regulation of proton motive force in gonococci.
• To determine the relationship between membrane potential and antibiotic resistance in N. gonorrhoeae.
• To identify the generators of membrane potential in gonococcal cells.

Main Methods:

• Measurement of proton motive force (PMF) across the cell membrane.
• Quantification of membrane potential (Δψ) and the transmembrane hydrogen ion gradient (ΔpH).
• Assessment of phenyldicarbaundecaborane absorption by N. gonorrhoeae vesicles.
• Evaluation of the effects of energy process inhibitors (KCN, DCCD, CCF) on PMF.

Main Results:

• Proton motive force in gonococci ranged from 183-192 mB as incubation medium pH shifted from 5 to 8.
• Membrane potential varied between 103-145 mB, and the hydrogen ion gradient (ΔpH) ranged from 47-90 mB.
• Phenyldicarbaundecaborane absorption indicated the respiratory chain and H(+)-ATPase as PMF generators.
• Inhibitors KCN, DCCD, and CCF suppressed PMF generators and dissipated membrane potential.
• Gonococci strains resistant to antibiotics displayed a higher membrane potential than sensitive strains.

Conclusions:

• The respiratory chain and H(+)-ATPase are the primary generators of proton motive force in N. gonorrhoeae.
• Inhibitors targeting energy processes effectively disrupt PMF and membrane potential.
• Elevated membrane potential in antibiotic-resistant gonococci suggests a potential role in resistance mechanisms.