Visualization of mycobacterial membrane dynamics in live cells

Area of Science:

• Microbiology
• Cell Biology
• Biochemistry

Background:

• Mycobacteria possess a robust mycomembrane, contributing to antibiotic resistance.
• The organization and dynamics of glycolipids within this membrane are not well understood.

Purpose of the Study:

• To investigate the dynamics of glycolipids in the mycobacterial mycomembrane.
• To explore how mycomembrane fluidity varies across different actinomycetes species.
• To assess the impact of ethambutol on mycomembrane dynamics.

Main Methods:

• Development and application of trehalose-fluorophore conjugates for labeling trehalose glycolipids in live actinomycetes.
• Metabolic incorporation of fluorescein-trehalose analogues into trehalose mycolates.
• Time-lapse microscopy and fluorescence recovery after photobleaching (FRAP) to study glycolipid mobility.

Main Results:

• Fluorescent probes were successfully incorporated into trehalose mycolates of Mycobacterium, Corynebacterium, Nocardia, and Rhodococcus species.
• Mycomembrane fluidity showed significant interspecies variation, correlating with mycolic acid structure.
• Treatment with ethambutol, a tuberculosis drug, markedly increased mycomembrane fluidity.

Conclusions:

• Trehalose-fluorophore conjugates provide a valuable tool for studying mycomembrane dynamics.
• Mycomembrane fluidity is a variable characteristic influenced by glycolipid structure and drug treatment.
• Findings offer insights into mycobacterial cell envelope structure and suggest potential strategies for tuberculosis drug development.