Details

Autor(en) / Beteiligte

• Herrmann, Moritz
• Schneck, Emanuel
• Gutsmann, Thomas
• Brandenburg, Klaus
• Tanaka, Motomu

Titel

Bacterial lipopolysaccharides form physically cross-linked, two-dimensional gels in the presence of divalent cationsElectronic supplementary information (ESI) available: Confirmation of linear response of LPS monolayer. See DOI: 10.1039/c5sm01002k

Erscheinungsjahr

2015-07

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• We established a bacterial membrane model with monolayers of bacterial lipopolysaccharides (LPS Re and LPS Ra) and quantified their viscoelastic properties by using an interfacial stress rheometer coupled to a Langmuir film balance. LPS Re monolayers exhibited purely viscous behaviour in the absence of calcium ions, while the same monolayers underwent a viscous-to-elastic transition upon compression in the presence of Ca 2+ . Our results demonstrated for the first time that LPSs in bacterial outer membranes can form two-dimensional elastic networks in the presence of Ca 2+ . Different from LPS Re monolayers, the LPS Ra monolayers showed a very similar rheological transition both in the presence and absence of Ca 2+ , suggesting that longer saccharide chains can form 2D physical gels even in the absence of Ca 2+ . By exposure of the monolayers to the antimicrobial peptide protamine, we could directly monitor the differences in resistance of bacterial membranes according to the presence of calcium. Interface rheology suggests bacteria blocks antibacterial peptides by forming physically cross-linked gels of lipopolysaccharides in the presence of divalent cations.