Nanotubes Formation in P. aeruginosa

Area of Science:

• Microbiology
• Cell Biology

Background:

• Pseudomonas aeruginosa can form biofilms, exhibiting diverse phenotypes including small colony variants (SCVs).
• SCVs are often associated with persistent infections and antibiotic tolerance.
• The structural and functional roles of SCVs within biofilms are not fully understood.

Purpose of the Study:

• To investigate the role of nanotubes in biofilm consortia formed by a P. aeruginosa isolate.
• To determine the contribution of these nanotubes to cell survival under stress conditions.
• To characterize the physical properties and connectivity of nanotubes.

Main Methods:

• Culturing of P. aeruginosa biofilm consortia at varying pH levels.
• Microscopic analysis using scanning electron microscopy (SEM) to visualize nanotubes.
• Application of physical pressure to assess nanotube stability and cell morphology.
• Measurement of cell volume before and after pressure application.

Main Results:

• SCVs formed nanotube networks connecting cells within the biofilm.
• Nanotubes were observed as polar appendages facilitating intraspecies connectivity.
• Cell volume significantly decreased under pressure, with nanotube producers showing greater resilience.
• Non-producers were eliminated under pressure, highlighting a selective advantage for nanotube formation.
• SCVs reverted to planktonic forms upon removal of stress and nutrient replenishment.

Conclusions:

• Nanotubes are not indicative of cell death but serve as crucial connectivity tools for P. aeruginosa SCVs.
• Nanotube formation confers a selective advantage, enabling cells to resist environmental stress and physical pressure.
• This intercellular network is vital for biofilm survival and adaptation.