Increased ion conductance across mammalian membranes modified with conjugated oligoelectrolytes

Du, Jenny; Thomas, Alexander; Chen, Xiaofen; Garner, Logan E.; Vandenberg, Carol A.; Bazan, Guillermo C.

doi:10.1039/c3cc45094e

Cited by 28 publications

(33 citation statements)

References 16 publications

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“…8,12 While genetic modi-cations can also improve permeability, they are oen more effective at enhancing transport across the IM than the OM and are complicated to implement alongside other genetic modi-cations, such as enzyme overexpression. 13 Thus, there is a paucity of well-characterized, one-step methods for altering membrane permeability that do not introduce additional limitations.…”

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confidence: 99%

“…14,15 COEs have a p-delocalized backbone bearing ionic pendant groups and are known to spontaneously intercalate into lipid bilayers. COEs have shown to improve electrochemical performance in devices utilizing yeast, 13 Escherichia coli, 16 Shewanella oneidensis, 10,15 mixed communities, 17 and even membrane-based photosystems.…”

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confidence: 99%

“…9,10,17,21,[23][24][25][26][27][28][29][30] Model membrane studies have shown that COEs increase ion conductance across the membrane. 13 To add to mechanistic complexity, recent results suggest that COEs may interact with other components in the cell envelope, such as lipopolysaccharides and cholic acid. [31][32][33] The degree to which such processes dominate bioelectrochemical changes, relative to electron transfer mechanisms, is not entirely known.…”

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confidence: 99%

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Membrane permeabilization by conjugated oligoelectrolytes accelerates whole-cell catalysis

2016

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Membrane permeabilization by conjugated oligoelectrolytes accelerates whole-cell catalysis

2016

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“…In this contribution, we examine the response of selected Gram-negative and Gram-positive organisms to three OPV-COE MIMs that have been the focus of previous studies (1,3,9,10). Furthermore, using a combination of specific deletion mutants along with a model membrane system, we will explore interactions between OPV-COEs and different components of the cellular envelope.…”

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confidence: 99%

Oligopolyphenylenevinylene-Conjugated Oligoelectrolyte Membrane Insertion Molecules Selectively Disrupt Cell Envelopes of Gram-Positive Bacteria

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et al. 2015

Appl Environ Microbiol

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The modification of microbial membranes to achieve biotechnological strain improvement with exogenous small molecules, such as oligopolyphenylenevinylene-conjugated oligoelectrolyte (OPV-COE) membrane insertion molecules (MIMs), is an emerging biotechnological field. Little is known about the interactions of OPV-COEs with their target, the bacterial envelope. We studied the toxicity of three previously reported OPV-COEs with a selection of Gram-negative and Gram-positive organisms and demonstrated that Gram-positive bacteria are more sensitive to OPV-COEs than Gram-negative bacteria. Transmission electron microscopy demonstrated that these MIMs disrupt microbial membranes and that this occurred to a much greater degree in Gram-positive organisms. We used a number of mutants to probe the nature of MIM interactions with the microbial envelope but were unable to align the membrane perturbation effects of these compounds to previously reported membrane disruption mechanisms of, for example, cationic antimicrobial peptides. Instead, the data support the notion that OPV-COEs disrupt microbial membranes through a suspected interaction with diphosphatidylglycerol (DPG), a major component of Grampositive membranes. The integrity of model membranes containing elevated amounts of DPG was disrupted to a greater extent by MIMs than those prepared from Escherichia coli total lipid extracts alone.

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“…COE1‐5C is encouraging as a candidate to mitigate membrane destabilization by organic solvents because of its low intrinsic toxicity and greater ability to impart rigidity to the lipid bilayer than other OPV COEs (Figure ). Furthermore, its affinity for biological membranes has been previously documented …”

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Increased Microbial Butanol Tolerance by Exogenous Membrane Insertion Molecules

et al. 2015

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Butanol is an ideal biofuel, although poor titers lead to high recovery costs by distillation. Fluidization of microbial membranes by butanol is one of the major factors limiting titers in butanol-producing bioprocesses. Starting with the hypothesis that certain membrane insertion molecules would stabilize the lipid bilayer in the presence of butanol, we applied a combination of in vivo and in vitro techniques within an in silico framework to describe a new approach to achieve solvent tolerance in bacteria. Single-molecule tracking of a model supported bilayer showed that COE1-5C, a five-ringed oligo-polyphenylenevinylene conjugated oligoelectrolyte (COE), reduced the diffusion rate of phospholipids in a microbially derived lipid bilayer to a greater extent than three-ringed and four-ringed COEs. Furthermore, COE1-5C treatment increased the specific growth rate of E. coli K12 relative to a control at inhibitory butanol concentrations. Consequently, to confer butanol tolerance to microbes by exogenous means is complementary to genetic modification of strains in industrial bioprocesses, extends the physiological range of microbes to match favorable bioprocess conditions, and is amenable with complex and undefined microbial consortia for biobutanol production. Molecular dynamics simulations indicated that the π-conjugated aromatic backbone of COE1-5C likely acts as a hydrophobic tether for glycerophospholipid acyl chains by enhancing bilayer integrity in the presence of high butanol concentrations, which thereby counters membrane fluidization. COE1-5C-mitigated E. coli K12 membrane depolarization by butanol is consistent with the hypothesis that improved growth rates in the presence of butanol are a consequence of improved bilayer stability.

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Increased ion conductance across mammalian membranes modified with conjugated oligoelectrolytes

Cited by 28 publications

References 16 publications

Membrane permeabilization by conjugated oligoelectrolytes accelerates whole-cell catalysis

Membrane permeabilization by conjugated oligoelectrolytes accelerates whole-cell catalysis

Oligopolyphenylenevinylene-Conjugated Oligoelectrolyte Membrane Insertion Molecules Selectively Disrupt Cell Envelopes of Gram-Positive Bacteria

Increased Microbial Butanol Tolerance by Exogenous Membrane Insertion Molecules

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