High Fluidity and Soft Elasticity of the Inner Membrane of Escherichia coli Revealed by the Surface Rheology of Model Langmuir Monolayers
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- 作者：Ivá ; n Ló ; pez-Montero ; Laura R. Arriaga ; Francisco Monroy ; Germá ; n Rivas ; Pedro Tarazona ; Marisela Vé ; lez
- 刊名：Langmuir
- 出版年：2008
- 出版时间：April 15, 2008
- 年：2008
- 卷：24
- 期：8
- 页码：4065 - 4076
- 全文大小：236K
- 年卷期：v.24,no.8(April 15, 2008)
- ISSN：1520-5827
文摘
We have studied the equilibrium and linear mechanical properties of model membranes of Escherichia coli builtup as Langmuir monolayers of a native lipid extract using surface thermodynamics, fluorescence microscopy, andsurface rheology measurements. The experimental study has been carried out at different temperatures across thephysiological operative range 15-37 
C. Lipid phase coexistence has been revealed over a broad pressure range byfluorescence microscopy. The presence of ordered domains has been invoked to explain the emergence of shearelasticity accompanying the hydrostatic compression elasticity typical of fluid monolayers. The surface rheologymeasurements point out the soft character of E. coli membranes; i.e., upon deformation they react as a near-idealcompliant body with minimal energy dissipation, thus optimizing the effectiveness of external stresses in producingmembrane deformations. These mechanical features appear to be independent of temperature, suggesting the existenceof a passive thermoregulation mechanism.
C. Lipid phase coexistence has been revealed over a broad pressure range byfluorescence microscopy. The presence of ordered domains has been invoked to explain the emergence of shearelasticity accompanying the hydrostatic compression elasticity typical of fluid monolayers. The surface rheologymeasurements point out the soft character of E. coli membranes; i.e., upon deformation they react as a near-idealcompliant body with minimal energy dissipation, thus optimizing the effectiveness of external stresses in producingmembrane deformations. These mechanical features appear to be independent of temperature, suggesting the existenceof a passive thermoregulation mechanism.