Extracellular slime associated with Proteus mirabilis during swarming

Area of Science:

• Microbiology
• Cell Biology

Background:

• Swarming motility is a complex behavior observed in various bacteria, including Proteus mirabilis.
• The role of extracellular slime in bacterial swarming is not fully understood.

Purpose of the Study:

• To visualize and characterize the extracellular slime produced by Proteus mirabilis swarm cells.
• To investigate the relationship between extracellular slime and swarm cell migration.

Main Methods:

• Light microscopy (phase-contrast microscopy)
• Transmission electron microscopy (TEM) with ruthenium red staining
• Scanning electron microscopy (SEM)

Main Results:

• Extensive extracellular slime was observed surrounding Proteus mirabilis swarm cells.
• The slime formed a matrix in which swarm cells were embedded and appeared to migrate.
• Nonswarming mutants exhibited cell elongation and increased flagellum synthesis, suggesting these are prerequisites for migration.

Conclusions:

• Proteus mirabilis swarm cells produce copious amounts of extracellular slime, likely facilitating migration.
• Further research is needed to determine if extracellular slime production is a strict requirement for swarm cell migration.