scholarly journals Outer Membrane Vesicles of Gram-Negative Bacteria: An Outlook on Biogenesis

2021 ◽  
Vol 12 ◽  
Author(s):  
Eric Daniel Avila-Calderón ◽  
María del Socorro Ruiz-Palma ◽  
Ma. Guadalupe Aguilera-Arreola ◽  
Norma Velázquez-Guadarrama ◽  
Enrico A. Ruiz ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Quorum Sensing ◽  
Outer Membrane ◽  
Molecular Mechanisms ◽  
Outer Membrane Proteins ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Cellular Components

Outer membrane vesicles (OMVs) from Gram-negative bacteria were first described more than 50 years ago. However, the molecular mechanisms involved in biogenesis began to be studied only in the last few decades. Presently, the biogenesis and molecular mechanisms for their release are not completely known. This review covers the most recent information on cellular components involved in OMV biogenesis, such as lipoproteins and outer membrane proteins, lipopolysaccharide, phospholipids, quorum-sensing molecules, and flagella.

scholarly journals Immunization withSalmonella entericaSerovar Typhimurium-Derived Outer Membrane Vesicles Delivering the Pneumococcal Protein PspA Confers Protection against Challenge withStreptococcus pneumoniae

2010 ◽  
Vol 79 (2) ◽  
pp. 887-894 ◽  
Author(s):  
Maneesha Muralinath ◽  
Meta J. Kuehn ◽  
Kenneth L. Roland ◽  
Roy Curtiss
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Lethal Dose ◽  
Serum Antibody ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Gram Negative Bacteria ◽  
Vesicle Preparation ◽  
Serovar Typhimurium

ABSTRACTGram-negative bacteria produce outer membrane vesicles (OMVs) that serve a variety of functions related to survival and pathogenicity. Periplasmic and outer membrane proteins are naturally captured during vesicle formation. This property has been exploited as a method to derive immunogenic vesicle preparations for use as vaccines. In this work, we constructed aSalmonella entericaserovar Typhimurium strain that synthesized a derivative of the pneumococcal protein PspA engineered to be secreted into the periplasmic space. Vesicles isolated from this strain contained PspA in the lumen. Mice intranasally immunized with the vesicle preparation developed serum antibody responses against vesicle components that included PspA andSalmonella-derived lipopolysaccharide and outer membrane proteins, while no detectable responses developed in mice immunized with an equivalent dose of purified PspA. Mucosal IgA responses developed against theSalmonellacomponents, while the response to PspA was less apparent in most mice. Mice immunized with the vesicle preparation were completely protected against a 10× 50% lethal dose (LD50) challenge ofStreptococcus pneumoniaeand significantly protected against a 200× LD50challenge, while control mice immunized with purified PspA or empty vesicles were not protected. These results establish that vesicles can be used to mucosally deliver an antigen from a Gram-positive organism and induce a protective immune response.

scholarly journals Role of Pseudomonas aeruginosa Peptidoglycan-Associated Outer Membrane Proteins in Vesicle Formation

2012 ◽  
Vol 195 (2) ◽  
pp. 213-219 ◽  
Author(s):  
Aimee K. Wessel ◽  
Jean Liew ◽  
Taejoon Kwon ◽  
Edward M. Marcotte ◽  
Marvin Whiteley
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Membrane Proteins ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Membrane Vesicles ◽  
Opportunistic Pathogen ◽  
Outer Membrane Vesicles ◽  
Gram Negative Bacteria ◽  
Content Type

ABSTRACTGram-negative bacteria produce outer membrane vesicles (OMVs) that package and deliver proteins, small molecules, and DNA to prokaryotic and eukaryotic cells. The molecular details of OMV biogenesis have not been fully elucidated, but peptidoglycan-associated outer membrane proteins that tether the outer membrane to the underlying peptidoglycan have been shown to be critical for OMV formation in multipleEnterobacteriaceae. In this study, we demonstrate that the peptidoglycan-associated outer membrane proteins OprF and OprI, but not OprL, impact production of OMVs by the opportunistic pathogenPseudomonas aeruginosa. Interestingly, OprF does not appear to be important for tethering the outer membrane to peptidoglycan but instead impacts OMV formation through modulation of the levels of thePseudomonasquinolone signal (PQS), a quorum signal previously shown by our laboratory to be critical for OMV formation. Thus, the mechanism by which OprF impacts OMV formation is distinct from that for other peptidoglycan-associated outer membrane proteins, including OprI.

scholarly journals Outer Membrane Vesicle Biosynthesis in Salmonella : Is There More to Gram-Negative Bacteria?

mBio ◽  
2016 ◽  
Vol 7 (4) ◽  
Author(s):  
Joachim Reidl
Keyword(s):  
Outer Membrane ◽  
Molecular Mechanisms ◽  
Membrane Vesicle ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Serovar Typhimurium ◽  
Reported Study

ABSTRACT Recent research has focused on the biological role of outer membrane vesicles (OMVs), which are derived from the outer membranes (OMs) of Gram-negative bacteria, and their potential exploitation as therapeutics. OMVs have been characterized in many ways and functions. Until recently, research focused on hypothetical and empirical models that addressed the molecular mechanisms of OMV biogenesis, such as vesicles bulging from the OM in various ways. The recently reported study by Elhenawy et al. (mBio 7:e00940-16, 2016, http://dx.doi.org/10.1128/mBio.00940-16 ) provided further insights into OMV biogenesis of Salmonella enterica serovar Typhimurium. That study showed that deacylation of lipopolysaccharides (LPS) influences the level of OMV production and, furthermore, determines a sorting of high versus low acylated LPS in OMs and OMVs, respectively. Interestingly, deacylation may inversely correlate with other LPS modifications, suggesting some synergy toward optimized host resistance via best OM compositions for S . Typhimurium.

scholarly journals Detection of Gram-negative bacterial outer membrane vesicles using DNA aptamers

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Hye-Su Shin ◽  
Vinayakumar Gedi ◽  
Joon-Ki Kim ◽  
Dong-ki Lee
Keyword(s):  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Severe Illness ◽  
Dna Aptamers ◽  
Gram Negative Bacteria ◽  
Human Beings ◽  
Gram Negative ◽  
Bacterial Outer Membrane

Abstract Infection of various pathogenic bacteria causes severe illness to human beings. Despite the research advances, current identification tools still exhibit limitations in detecting Gram-negative bacteria with high accuracy. In this study, we isolated single-stranded DNA aptamers against multiple Gram-negative bacterial species using Toggle-cell-SELEX (systemic evolution of ligands by exponential enrichment) and constructed an aptamer-based detection tool towards bacterial secretory cargo released from outer membranes of Gram-negative bacteria. Three Gram-negative bacteria, Escherichia coli DH5α, E. coli K12, and Serratia marcescens, were sequentially incubated with the pool of random DNA sequences at each SELEX loop. Two aptamers selected, GN6 and GN12, were 4.2-times and 3.6-times higher binding to 108 cells of Gram-negative bacteria than to Gram-positive bacteria tested, respectively. Using GN6 aptamer, we constructed an Enzyme-linked aptamer assay (ELAA) to detect bacterial outer membrane vesicles (OMVs) of Gram-negative bacteria, which contain several outer membrane proteins with potent immunostimulatory effects. The GN6-ELAA showed high sensitivity to detect as low as 25 ng/mL bacterial OMVs. Aptamers developed in this study show a great potential to facilitate medical diagnosis and early detection of bacterial terrorism, based on the ability to detect bacterial OMVs of multiple Gram-negative bacteria.

Electrophysiological Characterization of Transport Across Outer Membrane Channels from Gram-Negative Bacteria in Their Native Environment

2019 ◽  
Author(s):  
Jiajun Wang ◽  
Rémi Terrasse ◽  
Jayesh Arun Bafna ◽  
Lorraine Benier ◽  
Mathias Winterhalter
Keyword(s):  
Outer Membrane ◽  
Lipid Membrane ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Multi Drug Resistance ◽  
Gram Negative Bacteria ◽  
Membrane Channels ◽  
Gram Negative ◽  
Electrophysiological Characterization

Multi-drug resistance in Gram-negative bacteria is often associated with low permeability of the outer membrane. To investigate the role of membrane channels in the uptake of antibiotics, we extract, purify and reconstitute them into artificial planar membranes. To avoid this time-consuming procedure, here we show a robust approach using fusion of native outer membrane vesicles (OMV) into planar lipid bilayer which moreover allows also to some extend the characterization of membrane protein channels in their native environment. Two major membrane channels from <i>Escherichia coli</i>, OmpF and OmpC, were overexpressed from the host and the corresponding OMVs were collected. Each OMV fusion revealed surprisingly single or only few channel activities. The asymmetry of the OMV´s translates after fusion into the lipid membrane with the LPS dominantly present at the side of OMV addition. Compared to conventional reconstitution methods, the channels fused from OMVs containing LPS have similar conductance but a much broader distribution. The addition of Enrofloxacin on the LPS side yields somewhat higher association (<i>k<sub>on</sub></i>) and lower dissociation (<i>k<sub>off</sub></i>) rates compared to LPS-free reconstitution. We conclude that using outer membrane vesicles is a fast and easy approach for functional and structural studies of membrane channels in the native membrane.

scholarly journals Functions of the BamBCDE Lipoproteins Revealed by Bypass Mutations in BamA

2020 ◽  
Vol 202 (21) ◽  
Author(s):  
Elizabeth M. Hart ◽  
Thomas J. Silhavy
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Gram Negative Bacteria ◽  
Wild Type ◽  
Gram Negative ◽  
Bam Complex ◽  
Essential Function ◽  
The Individual

ABSTRACT The heteropentomeric β-barrel assembly machine (BAM complex) is responsible for folding and inserting a diverse array of β-barrel outer membrane proteins (OMPs) into the outer membrane (OM) of Gram-negative bacteria. The BAM complex contains two essential proteins, the β-barrel OMP BamA and a lipoprotein BamD, whereas the auxiliary lipoproteins BamBCE are individually nonessential. Here, we identify and characterize three bamA mutations, the E-to-K change at position 470 (bamAE470K), the A-to-P change at position 496 (bamAA496P), and the A-to-S change at position 499 (bamAA499S), that suppress the otherwise lethal ΔbamD, ΔbamB ΔbamC ΔbamE, and ΔbamC ΔbamD ΔbamE mutations. The viability of cells lacking different combinations of BAM complex lipoproteins provides the opportunity to examine the role of the individual proteins in OMP assembly. Results show that, in wild-type cells, BamBCE share a redundant function; at least one of these lipoproteins must be present to allow BamD to coordinate productively with BamA. Besides BamA regulation, BamD shares an additional essential function that is redundant with a second function of BamB. Remarkably, bamAE470K suppresses both, allowing the construction of a BAM complex composed solely of BamAE470K that is able to assemble OMPs in the absence of BamBCDE. This work demonstrates that the BAM complex lipoproteins do not participate in the catalytic folding of OMP substrates but rather function to increase the efficiency of the assembly process by coordinating and regulating the assembly of diverse OMP substrates. IMPORTANCE The folding and insertion of β-barrel outer membrane proteins (OMPs) are conserved processes in mitochondria, chloroplasts, and Gram-negative bacteria. In Gram-negative bacteria, OMPs are assembled into the outer membrane (OM) by the heteropentomeric β-barrel assembly machine (BAM complex). In this study, we probe the function of the individual BAM proteins and how they coordinate assembly of a diverse family of OMPs. Furthermore, we identify a gain-of-function bamA mutant capable of assembling OMPs independently of all four other BAM proteins. This work advances our understanding of OMP assembly and sheds light on how this process is distinct in Gram-negative bacteria.

scholarly journals Spheres of Hope, Packets of Doom: the Good and Bad of Outer Membrane Vesicles in Interspecies and Ecological Dynamics

2017 ◽  
Vol 199 (15) ◽  
Author(s):  
Jonathan B. Lynch ◽  
Rosanna A. Alegado
Keyword(s):  
Antimicrobial Activity ◽  
Horizontal Gene Transfer ◽  
Outer Membrane ◽  
Recent Progress ◽  
Membrane Vesicles ◽  
Stress Relief ◽  
Outer Membrane Vesicles ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
By Products

ABSTRACT Outer membrane vesicles (OMVs) are proteoliposome nanoparticles ubiquitously produced by Gram-negative bacteria. Typically bearing a composition similar to those of the outer membrane and periplasm of the cells from which they are derived, OMVs package an array of proteins, lipids, and nucleic acids. Once considered inconsequential by-products of bacterial growth, OMVs have since been demonstrated to mediate cellular stress relief, promote horizontal gene transfer and antimicrobial activity, and elicit metazoan inflammation. Recently, OMVs have gained appreciation as critical moderators of interorganismal dynamics. In this review, we focus on recent progress toward understanding the functions of OMVs with regard to symbiosis and ecological contexts, and we propose potential avenues for future OMV studies.

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