Work

Pseudomonas aeruginosa assembles H1-T6SS in response to physical and chemical damage of the outer membrane

Year: 2025

Type: article

Abstract: Bacteria respond to environmental stimuli and attacks from competing organisms. Pseudomonas aeruginosa assembles the type VI secretion system (H1-T6SS) to precisely retaliate against aggressive competing bacteria. However, we lack an understanding of how the H1-T6SS assembly dynamically responds to nanomechanical forces. To address this, we analyzed live cells using correlative atomic force microscopy (AFM) and fluorescence microscopy. We show that indentation forces above 7 nanonewtons trigger local, repeated and targeted H1-T6SS assemblies within seconds of impact by the AFM tip. Analysis of the corresponding AFM force curves shows that a breach of a single layer of the cell envelope is necessary and sufficient for triggering H1-T6SS assembly. Accordingly, polymyxin B nonapeptide, which damages the outer membrane, also triggers H1-T6SS assembly. This suggests that P. aeruginosa has evolved a danger-sensing mechanism that enables rapid and precise deployment of its antibacterial H1-T6SS in response to breaches in the outer membrane.

Source: Science Advances

DOI: 10.1126/sciadv.adr1713

Authors: Mitchell Brüderlin, Maxim Kolesnikov, Florian Röthlin, Roderick Y. H. Lim, Marek Basler

Institutions: University of Basel, Swiss Nanoscience Institute

Language: English

Topic: Bacterial Genetics and Biotechnology

Subfield: Genetics

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: gold

Estimated APC paid: $4,500

Funder: Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung