Sliding motility in mycobacteria

Area of Science:

• Microbiology
• Cell Biology
• Bacterial Physiology

Background:

• Mycobacteria are Gram-positive microorganisms.
• Previously, mycobacteria were considered nonmotile.

Purpose of the Study:

• To investigate the motility of Mycobacterium smegmatis.
• To determine the mechanism and characteristics of mycobacterial surface translocation.
• To explore if this motility is conserved in other mycobacterial species.

Main Methods:

• Microscopic observation of Mycobacterium smegmatis spreading on growth medium.
• Analysis of cell arrangements and interactions during translocation.
• Correlation of motility with the presence of specific cell envelope components.
• Testing for surface motility in Mycobacterium avium.

Main Results:

• Mycobacterium smegmatis exhibits surface motility via a sliding mechanism.
• Cells spread as a monolayer in pseudofilaments, moving as a unit.
• Extracellular structures like pili are not involved; motility correlates with glycopeptidolipids.
• Surface motility is also demonstrated in Mycobacterium avium.

Conclusions:

• Mycobacteria possess a previously unrecognized surface sliding motility.
• Glycopeptidolipids are implicated in this translocation.
• This motility may be crucial for mycobacterial colonization in various environments and hosts.