Sulphur acquisition by Neisseria meningitidis

Area of Science:

• Microbiology
• Bacterial Physiology
• Nutrient Metabolism

Background:

• Neisseria meningitidis is a significant human pathogen.
• Understanding bacterial nutrient requirements is crucial for pathogenesis and treatment.
• Sulfur metabolism in bacteria is diverse and essential for growth.

Purpose of the Study:

• To investigate the ability of Group B Neisseria meningitidis (SD1C) to utilize various sulfur compounds as the sole sulfur source.
• To determine the optimal conditions for sulfur transport assessment in this bacterium.
• To characterize the kinetics of sulfate uptake.

Main Methods:

• Culturing Neisseria meningitidis on defined media with different sulfur compounds.
• Sulphur starvation protocols to induce nutrient-limited conditions.
• Sulfate uptake assays using radiolabeled sulfate to determine kinetic parameters (Vmax, Km).

Main Results:

• Group B Neisseria meningitidis demonstrated growth on a wide range of sulfur compounds, including sulfate, thiosulfate, and various amino acids.
• Significant growth was observed at low micromolar concentrations of sulfate and thiosulfate.
• Sulfate-starved cells exhibited enhanced sulfate transport capacity.
• Kinetic analysis revealed a high maximal sulfate uptake velocity (9.3 nmol/mg protein/min) and a low apparent Km (1.4 microM).

Conclusions:

• Group B Neisseria meningitidis possesses a versatile sulfur assimilation pathway.
• The bacterium efficiently scavenges sulfate, even at concentrations below physiological levels in the human host.
• The characterized sulfate transport system is highly effective, suggesting its importance in meningococcal survival and colonization.