Changes in fluidity of the <i>E. coli</i> outer membrane in response to temperature, divalent cations and polymyxin‐B show two different mechanisms of membrane fluidity adaptation

Ginez, Luis David; Osorio, Aurora; Vázquez‐Ramírez, Ricardo; Arenas, Thelma; Mendoza, Luis; Camarena, Laura; Poggio, Sebastián

doi:10.1111/febs.16358

Cited by 7 publications

(3 citation statements)

References 84 publications

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“…2 ) ( 41 ). The lipophilic dye FM 4-64 is an amphipathic molecule with a lipophilic tail and trivalent cation moiety, which can interact with LPS by both electrostatic and hydrophobic interactions ( 42 ). The addition of FM 4-64 to cells could result in homogeneous fluorescence across the cell surface in all PMB S and PMB R strains, implying that the PEtN-driven modification of lipid A was not associated with hydrophobic interactions with FM 4-64 ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Constitutive Phenotypic Modification of Lipid A in Clinical Acinetobacter baumannii Isolates

2022

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Section: Resultsmentioning

confidence: 99%

Constitutive Phenotypic Modification of Lipid A in Clinical Acinetobacter baumannii Isolates

2022

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“…Finally, we conclude that regardless of precisely controlled environmental conditions and geometrical parameters of the microchip, electroporation results in a highly heterogeneous outcome with respect to cell survival and internalization of DNA into the cells. Although we cannot completely rule out that this heterogeneity is caused by imperfections in the 24 manufacturing process of our miniaturized platform, it likely originates from naturally occurring cell-to-cell variations in the cell membrane composition (Ginez et al 2022), cell cycle stage at the time of the pulse, stochastic variation in gene expression, and the stochastic nature of the stability and number of electropores (Glaser et al 1988;Kotnik et al 2019). This observation further underscores the importance of a platform capable of performing single-cell electroporation, both for the direct study of the process to better understand the factors responsible for the cell-to-cell variations in electroporation outcome, and for advanced singlecell studies of electroporated cells.…”

Section: Discussionmentioning

confidence: 99%

A microfluidic platform forin situstudies of bacteria electroporation

Volkov,

Khaji,

Johansson

et al. 2024

Preprint

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Electroporation of dye-labelled bio-molecules has proven to be a valuable alternative to fluorescent protein fusion for single-molecule tracking in living cells. However, control over cell viability, electroporation efficiency and environment conditions before, during and after electroporation is difficult to achieve in bulk experiments. Here, we present a microfluidic platform capable of single-cell electroporation with in situ microscopy and demonstrate delivery of DNA into bacteria. Via real time observation of the electroporation process, we find that the effect of electrophoresis plays an important role when performing electroporation in a miniaturized platform and show that its undesired action can be balanced by using bipolar electrical pulses. We suggest that a low temperature of the sample during electroporation is important for cell viability not due to compensation for Joule heating, but due to temperature-dependant viscoelastic properties of the cell membrane. We further found that the presence of low conductive liquid between cells and the electrodes leads to a voltage divider effect which strongly influences the success of on-chip electroporation. Finally, we conclude that electroporation is intrinsically a highly stochastic process that is difficult to fully control via external parameters and envision that the microfluidic system presented here, capable of single-cell read-out, can be used for further fundamental studies to increase our understanding of the electroporation process.

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“…After exposure to various stresses, including divalent cation deprivation, EDTA (ethylenediaminetetraacetic acid), phages, antibiotics, or heat shock [ 40 , 41 ], Gram-negative bacteria regulate their OM homeostasis by, among other things, disturbing LPS and accumulating GPLs at the outer leaflet of the OM [ 9 , 42 ]. MlaA removes mislocalized GPLs from the outer leaflet of the OM and transfers them to a periplasmic soluble protein [ 32 ], MlaC [ 43 , 44 ].…”

Section: Maintenance Of Om Asymmetry: the Mla Systemmentioning

confidence: 99%

Maintenance of bacterial outer membrane lipid asymmetry: insight into MlaA

Kaur,

Mingeot -Leclercq

2024

BMC Microbiol

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The outer membrane (OM) of Gram-negative bacteria acts as an effective barrier to protect against toxic compounds. By nature, the OM is asymmetric with the highly packed lipopolysaccharide (LPS) at the outer leaflet and glycerophospholipids at the inner leaflet. OM asymmetry is maintained by the Mla system, in which is responsible for the retrograde transport of glycerophospholipids from the OM to the inner membrane. This system is comprised of six Mla proteins, including MlaA, an OM lipoprotein involved in the removal of glycerophospholipids that are mis-localized at the outer leaflet of the OM. Interestingly, MlaA was initially identified - and called VacJ - based on its role in the intracellular spreading of Shigella flexneri.Many open questions remain with respect to the Mla system and the mechanism involved in the translocation of mislocated glycerophospholipids at the outer leaflet of the OM, by MlaA. After summarizing the current knowledge on MlaA, we focus on the impact of mlaA deletion on OM lipid composition and biophysical properties of the OM. How changes in OM lipid composition and biophysical properties can impact the generation of membrane vesicles and membrane permeability is discussed. Finally, we explore whether and how MlaA might be a candidate for improving the activity of antibiotics and as a vaccine candidate.Efforts dedicated to understanding the relationship between the OM lipid composition and the mechanical strength of the bacterial envelope and, in turn, how such properties act against external stress, are needed for the design of new targets or drugs for Gram-negative infections.

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Changes in fluidity of the E. coli outer membrane in response to temperature, divalent cations and polymyxin‐B show two different mechanisms of membrane fluidity adaptation

Cited by 7 publications

References 84 publications

Constitutive Phenotypic Modification of Lipid A in Clinical Acinetobacter baumannii Isolates

Constitutive Phenotypic Modification of Lipid A in Clinical Acinetobacter baumannii Isolates

A microfluidic platform forin situstudies of bacteria electroporation

Maintenance of bacterial outer membrane lipid asymmetry: insight into MlaA

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