scholarly journals SalmonellaTol-Pal Reduces Outer Membrane Glycerophospholipid Levels for Envelope Homeostasis and Survival during Bacteremia

2018 ◽  
Vol 86 (7) ◽  
Author(s):  
Revathi Masilamani ◽  
Melina B. Cian ◽  
Zachary D. Dalebroux
Keyword(s):  
Outer Membrane ◽  
Membrane Lipids ◽  
Lipid Homeostasis ◽  
Content Type ◽  
Bacterial Morphology ◽  
Serovar Typhimurium ◽  
Genes Encoding ◽  
Rifampin Resistance ◽  
Mutant Phenotypes ◽  
Acyl Coenzyme A

ABSTRACTSalmonellae regulate membrane lipids during infection, but the exact proteins and mechanisms that promote their survival during bacteremia remain largely unknown. Mutations in genes encoding the conservedSalmonella entericaserovar Typhimurium (S. Typhimurium) Tol-Pal apparatus caused the outer membrane (OM) sensor lipoprotein, RcsF, to become activated. The capsule activation phenotype for the mutants suggested that Tol-Pal might influence envelope lipid homeostasis. The mechanism involves reducing OM glycerophospholipid (GPL) levels, since the mutant salmonellae similarly accumulated phosphatidylglycerols (PGl) and phosphatidylethanolamines (PE) within the OM in comparison to the wild type. The data support theEscherichia colimodel, whereby Tol-Pal directs retrograde GPL translocation across the periplasm. TheS. Typhimurium mechanism involves contributions from YbgC, a cytoplasmic acyl coenzyme A (acyl-CoA) thioesterase, and CpoB, a periplasmic TolA-binding protein. The functional relationship between Tol-Pal and YbgC and CpoB was previously unresolved. TheS. Typhimurium Tol-Pal proteins contribute similarly toward promoting OM-GPL homeostasis and Rcs signaling inactivity but differently toward promoting bacterial morphology, rifampin resistance, survival in macrophages, and survival in mice. For example,tolQ,tolR,tolA, andcpoBmutants were significantly more attenuated thanybgC,tolB, andpalmutants in a systemic mouse model of disease. Therefore, key roles exist for TolQ, TolR, TolA, and CpoB during murine bacteremia, which are independent of maintaining GPL homeostasis. The ability of TolQR to channel protons across the inner membrane (IM) is necessary forS. Typhimurium TolQRA function, since mutating conserved channel-facing residues rendered TolQ ineffective at rescuing deletion mutant phenotypes. Therefore, Tol-Pal promotesS. Typhimurium survival during bacteremia, in part, by reducing OM GPL concentrations, while TolQRA and CpoB enhance systemic virulence by additional mechanisms.

scholarly journals Association of a Protective Monoclonal IgA with the O Antigen of Salmonella enterica Serovar Typhimurium Impacts Type 3 Secretion and Outer Membrane Integrity

2012 ◽  
Vol 80 (7) ◽  
pp. 2454-2463 ◽  
Author(s):  
Stephen J. Forbes ◽  
Daniel Martinelli ◽  
Chyongere Hsieh ◽  
Jeffrey G. Ault ◽  
Michael Marko ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Epithelial Cells ◽  
Outer Membrane ◽  
Salmonella Enterica ◽  
Membrane Integrity ◽  
Effector Proteins ◽  
Content Type ◽  
O Antigen ◽  
Serovar Typhimurium ◽  
Type 3

ABSTRACTInvasion of intestinal epithelial cells bySalmonella entericaserovar Typhimurium is an energetically demanding process, involving the transfer of effector proteins from invading bacteria into host cells via a specialized organelle known as theSalmonellapathogenicity island 1 (SPI-1) type 3 secretion system (T3SS). By a mechanism that remains poorly understood, entry ofS. Typhimurium into epithelial cells is inhibited by Sal4, a monoclonal, polymeric IgA antibody that binds an immunodominant epitope within the O-antigen (O-Ag) component of lipopolysaccharide. In this study, we investigated how the binding of Sal4 to the surface ofS. Typhimurium influences T3SS activity, bacterial energetics, and outer membrane integrity. We found that Sal4 treatment impaired T3SS-mediated translocon formation and attenuated the delivery of tagged effector proteins into epithelial cells. Sal4 treatment coincided with a partial reduction in membrane energetics and intracellular ATP levels, possibly explaining the impairment in T3SS activity. Sal4's effects on bacterial secretion and energetics occurred concurrently with an increase in O-Ag levels in culture supernatants, alterations in outer membrane permeability, and changes in surface ultrastructure, as revealed by transmission electron microscopy and cryo-electron microscopy. We propose that Sal4, by virtue of its ability to bind and cross-link the O-Ag, induces a form of outer membrane stress that compromises the integrity of theS. Typhimurium cell envelope and temporarily renders the bacterium avirulent.

scholarly journals Display of Recombinant Proteins on Bacterial Outer Membrane Vesicles by Using Protein Ligation

2018 ◽  
Vol 84 (8) ◽  
pp. e02567-17 ◽  
Author(s):  
H. Bart van den Berg van Saparoea ◽  
Diane Houben ◽  
Marien I. de Jonge ◽  
Wouter S. P. Jong ◽  
Joen Luirink
Keyword(s):  
Escherichia Coli ◽  
Outer Membrane ◽  
Salmonella Enterica ◽  
Membrane Vesicles ◽  
Therapeutic Agents ◽  
Outer Membrane Vesicles ◽  
High Density ◽  
Content Type ◽  
Protein Ligation ◽  
Serovar Typhimurium

ABSTRACT The Escherichia coli virulence factor hemoglobin protease (Hbp) has been engineered into a surface display system that can be expressed to high density on live E. coli and Salmonella enterica serovar Typhimurium cells or derived outer membrane vesicles (OMVs). Multiple antigenic sequences can be genetically fused into the Hbp core structure for optimal exposure to the immune system. Although the Hbp display platform is relatively tolerant, increasing the number, size, and complexity of integrated sequences generally lowers the expression of the fused constructs and limits the density of display. This is due to the intricate mechanism of Hbp secretion across the outer membrane and the efficient quality control of translocation-incompetent chimeric Hbp molecules in the periplasm. To address this shortcoming, we explored the coupling of purified proteins to the Hbp carrier after its translocation across the outer membrane using the recently developed SpyTag/SpyCatcher protein ligation system. As expected, fusion of the small SpyTag to Hbp did not hamper display on OMVs. Subsequent addition of purified proteins fused to the SpyCatcher domain resulted in efficient covalent coupling to Hbp-SpyTag. Using in addition the orthogonal SnoopTag/SnoopCatcher system, multiple antigen modules could be coupled to Hbp in a sequential ligation strategy. Not only antigens proved suitable for Spy-mediated ligation but also nanobodies. Addition of this functionality to the platform might allow the targeting of live bacterial or OMV vaccines to certain tissues or immune cells to tailor immune responses.IMPORTANCE Outer membrane vesicles (OMVs) derived from Gram-negative bacteria attract increasing interest in the development of vaccines and therapeutic agents. We aim to construct a semisynthetic OMV platform for recombinant antigen presentation on OMVs derived from attenuated Salmonella enterica serovar Typhimurium cells displaying an adapted Escherichia coli autotransporter, Hbp, at the surface. Although this autotransporter accepts substantial modifications, its capacity with respect to the number, size, and structural complexity of the antigens genetically fused to the Hbp carrier is restricted. Here we describe the application of SpyCatcher/SpyTag protein ligation technology to enzymatically link antigens to Hbp present at high density in OMVs. Protein ligation was apparently unobstructed by the membrane environment and allowed a high surface density of coupled antigens, a property we have shown to be important for vaccine efficacy. The OMV coupling procedure appears versatile and robust, allowing fast production of experimental vaccines and therapeutic agents through a modular plug-and-display procedure.

scholarly journals Localized Hypermutation is the Major Driver of Meningococcal Genetic Variability during Persistent Asymptomatic Carriage

mBio ◽  
2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Luke R. Green ◽  
Ali A. Al-Rubaiawi ◽  
Mohammad A. R. M. Al-Maeni ◽  
Odile B. Harrison ◽  
Matthew Blades ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Gene Transfer ◽  
Outer Membrane ◽  
Antigenic Variation ◽  
Allelic Variation ◽  
Host Responses ◽  
Content Type ◽  
Type Iv ◽  
Asymptomatic Carriage ◽  
Genes Encoding

ABSTRACT Host persistence of bacteria is facilitated by mutational and recombinatorial processes that counteract loss of genetic variation during transmission and selection from evolving host responses. Genetic variation was investigated during persistent asymptomatic carriage of Neisseria meningitidis. Interrogation of whole-genome sequences for paired isolates from 25 carriers showed that de novo mutations were infrequent, while horizontal gene transfer occurred in 16% of carriers. Examination of multiple isolates per time point enabled separation of sporadic and transient allelic variation from directional variation. A comprehensive comparative analysis of directional allelic variation with hypermutation of simple sequence repeats and hyperrecombination of class 1 type IV pilus genes detected an average of seven events per carrier and 2:1 bias for changes due to localized hypermutation. Directional genetic variation was focused on the outer membrane with 69% of events occurring in genes encoding enzymatic modifiers of surface structures or outer membrane proteins. Multiple carriers exhibited directional and opposed switching of allelic variants of the surface-located Opa proteins that enables continuous expression of these adhesins alongside antigenic variation. A trend for switching from PilC1 to PilC2 expression was detected, indicating selection for specific alterations in the activities of the type IV pilus, whereas phase variation of restriction modification (RM) systems, as well as associated phasevarions, was infrequent. We conclude that asymptomatic meningococcal carriage on mucosal surfaces is facilitated by frequent localized hypermutation and horizontal gene transfer affecting genes encoding surface modifiers such that optimization of adhesive functions occurs alongside escape of immune responses by antigenic variation. IMPORTANCE Many bacterial pathogens coexist with host organisms, rarely causing disease while adapting to host responses. Neisseria meningitidis, a major cause of meningitis and septicemia, is a frequent persistent colonizer of asymptomatic teenagers/young adults. To assess how genetic variation contributes to host persistence, whole-genome sequencing and hypermutable sequence analyses were performed on multiple isolates obtained from students naturally colonized with meningococci. High frequencies of gene transfer were observed, occurring in 16% of carriers and affecting 51% of all nonhypermutable variable genes. Comparative analyses showed that hypermutable sequences were the major mechanism of variation, causing 2-fold more changes in gene function than other mechanisms. Genetic variation was focused on genes affecting the outer membrane, with directional changes in proteins responsible for bacterial adhesion to host surfaces. This comprehensive examination of genetic plasticity in individual hosts provides a significant new platform for rationale design of approaches to prevent the spread of this pathogen.

scholarly journals Decoration of Outer Membrane Vesicles with Multiple Antigens by Using an Autotransporter Approach

2014 ◽  
Vol 80 (18) ◽  
pp. 5854-5865 ◽  
Author(s):  
Maria H. Daleke-Schermerhorn ◽  
Tristan Felix ◽  
Zora Soprova ◽  
Corinne M. ten Hagen-Jongman ◽  
David Vikström ◽  
...  
Keyword(s):  
Immune Responses ◽  
Outer Membrane ◽  
Vaccine Development ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Heterologous Proteins ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Heterologous Antigens

ABSTRACTOuter membrane vesicles (OMVs) are spherical nanoparticles that naturally shed from Gram-negative bacteria. They are rich in immunostimulatory proteins and lipopolysaccharide but do not replicate, which increases their safety profile and renders them attractive vaccine vectors. By packaging foreign polypeptides in OMVs, specific immune responses can be raised toward heterologous antigens in the context of an intrinsic adjuvant. Antigens exposed at the vesicle surface have been suggested to elicit protection superior to that from antigens concealed inside OMVs, but hitherto robust methods for targeting heterologous proteins to the OMV surface have been lacking. We have exploited our previously developed hemoglobin protease (Hbp) autotransporter platform for display of heterologous polypeptides at the OMV surface. One, two, or three of theMycobacterium tuberculosisantigens ESAT6, Ag85B, and Rv2660c were targeted to the surface ofEscherichia coliOMVs upon fusion to Hbp. Furthermore, a hypervesiculating ΔtolRΔtolAderivative of attenuatedSalmonella entericaserovar Typhimurium SL3261 was generated, enabling efficient release and purification of OMVs decorated with multiple heterologous antigens, exemplified by theM. tuberculosisantigens and epitopes fromChlamydia trachomatismajor outer membrane protein (MOMP). Also, we showed that delivery ofSalmonellaOMVs displaying Ag85B to antigen-presenting cellsin vitroresults in processing and presentation of an epitope that is functionally recognized by Ag85B-specific T cell hybridomas. In conclusion, the Hbp platform mediates efficient display of (multiple) heterologous antigens, individually or combined within one molecule, at the surface of OMVs. Detection of antigen-specific immune responses upon vesicle-mediated delivery demonstrated the potential of our system for vaccine development.

scholarly journals A Subset of Exoribonucleases Serve as Degradative Enzymes for pGpG in c-di-GMP Signaling

2018 ◽  
Vol 200 (24) ◽  
Author(s):  
Mona W. Orr ◽  
Cordelia A. Weiss ◽  
Geoffrey B. Severin ◽  
Husan Turdiev ◽  
Soo-Kyoung Kim ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacillus Anthracis ◽  
Vibrio Cholerae ◽  
Biofilm Formation ◽  
Feedback Inhibition ◽  
Product Inhibition ◽  
Systematic Screening ◽  
Content Type ◽  
Genes Encoding ◽  
Mutant Phenotypes

ABSTRACT Bis-(3′-5′)-cyclic dimeric GMP (c-di-GMP) is a bacterial second messenger that regulates processes, such as biofilm formation and virulence. During degradation, c-di-GMP is first linearized to 5′-phosphoguanylyl-(3′,5′)-guanosine (pGpG) and subsequently hydrolyzed to two GMPs by a previously unknown enzyme, which was recently identified in Pseudomonas aeruginosa as the 3′-to-5′ exoribonuclease oligoribonuclease (Orn). Mutants of orn accumulated pGpG, which inhibited the linearization of c-di-GMP. This product inhibition led to elevated c-di-GMP levels, resulting in increased aggregate and biofilm formation. Thus, the hydrolysis of pGpG is crucial to the maintenance of c-di-GMP homeostasis. How species that utilize c-di-GMP signaling but lack an orn ortholog hydrolyze pGpG remains unknown. Because Orn is an exoribonuclease, we asked whether pGpG hydrolysis can be carried out by genes that encode protein domains found in exoribonucleases. From a screen of these genes from Vibrio cholerae and Bacillus anthracis, we found that only enzymes known to cleave oligoribonucleotides (orn and nrnA) rescued the P. aeruginosa Δorn mutant phenotypes to the wild type. Thus, we tested additional RNases with demonstrated activity against short oligoribonucleotides. These experiments show that only exoribonucleases previously reported to degrade short RNAs (nrnA, nrnB, nrnC, and orn) can also hydrolyze pGpG. A B. subtilis nrnA nrnB mutant had elevated c-di-GMP, suggesting that these two genes serve as the primary enzymes to degrade pGpG. These results indicate that the requirement for pGpG hydrolysis to complete c-di-GMP signaling is conserved across species. The final steps of RNA turnover and c-di-GMP turnover appear to converge at a subset of RNases specific for short oligoribonucleotides. IMPORTANCE The bacterial bis-(3′-5′)-cyclic dimeric GMP (c-di-GMP) signaling molecule regulates complex processes, such as biofilm formation. c-di-GMP is degraded in two-steps, linearization into pGpG and subsequent cleavage to two GMPs. The 3′-to-5′ exonuclease oligoribonuclease (Orn) serves as the enzyme that degrades pGpG in Pseudomonas aeruginosa. Many phyla contain species that utilize c-di-GMP signaling but lack an Orn homolog, and the protein that functions to degrade pGpG remains uncharacterized. Here, systematic screening of genes encoding proteins containing domains found in exoribonucleases revealed a subset of genes encoded within the genomes of Bacillus anthracis and Vibrio cholerae that degrade pGpG to GMP and are functionally analogous to Orn. Feedback inhibition by pGpG is a conserved process, as strains lacking these genes accumulate c-di-GMP.

scholarly journals A Single Nucleotide Polymorphism in lptG Increases Tolerance to Bile Salts, Acid, and Staining of Calcofluor-Binding Polysaccharides in Salmonella enterica Serovar Typhimurium E40

2021 ◽  
Vol 12 ◽  
Author(s):  
Taylor A. Wahlig ◽  
Eliot Stanton ◽  
Jared J. Godfrey ◽  
Andrew J. Stasic ◽  
Amy C. L. Wong ◽  
...  
Keyword(s):  
Single Nucleotide Polymorphism ◽  
Outer Membrane ◽  
Salmonella Enterica ◽  
Bile Salts ◽  
Transcriptional Analysis ◽  
Variant Form ◽  
Nucleotide Polymorphism ◽  
Single Nucleotide ◽  
Serovar Typhimurium ◽  
Genes Encoding

The outer membrane of Salmonella enterica plays an important role in combating stress encountered in the environment and hosts. The transport and insertion of lipopolysaccharides (LPS) into the outer membrane involves lipopolysaccharide transport proteins (LptA-F) and mutations in the genes encoding for these proteins are often lethal or result in the transport of atypical LPS that can alter stress tolerance in bacteria. During studies of heterogeneity in bile salts tolerance, S. enterica serovar Typhimurium E40 was segregated into bile salts tolerant and sensitive cells by screening for growth in TSB with 10% bile salts. An isolate (E40V) with a bile salts MIC >20% was selected for further characterization. Whole-genome sequencing of E40 and E40V using Illumina and PacBio SMRT technologies revealed a non-synonymous single nucleotide polymorphism (SNP) in lptG. Leucine at residue 26 in E40 was substituted with proline in E40V. In addition to growth in the presence of 10% bile salts, E40V was susceptible to novobiocin while E40 was not. Transcriptional analysis of E40 and E40V, in the absence of bile salts, revealed significantly greater (p < 0.05) levels of transcript in three genes in E40V; yjbE (encoding for an extracellular polymeric substance production protein), yciE (encoding for a putative stress response protein), and an uncharacterized gene annotated as an acid shock protein precursor (ASPP). No transcripts of genes were present at a greater level in E40 compared to E40V. Corresponding with the greater level of these transcripts, E40V had greater survival at pH 3.35 and staining of Calcofluor-binding polysaccharide (CBPS). To confirm the SNP in lptG was associated with these phenotypes, strain E40E was engineered from E40 to encode for the variant form of LptG (L26P). E40E exhibited the same differences in gene transcripts and phenotypes as E40V, including susceptibility to novobiocin, confirming the SNP was responsible for these differences.

scholarly journals Phosphate Groups of Lipid A Are Essential for Salmonella enterica Serovar Typhimurium Virulence and Affect Innate and Adaptive Immunity

2012 ◽  
Vol 80 (9) ◽  
pp. 3215-3224 ◽  
Author(s):  
Qingke Kong ◽  
David A. Six ◽  
Qing Liu ◽  
Lillian Gu ◽  
Shifeng Wang ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Adaptive Immunity ◽  
Salmonella Enterica ◽  
Lipid A ◽  
Outer Membrane Proteins ◽  
Polymyxin B ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Phosphate Groups

ABSTRACTLipid A is a key component of the outer membrane of Gram-negative bacteria and stimulates proinflammatory responses via the Toll-like receptor 4 (TLR4)-MD2-CD14 pathway. Its endotoxic activity depends on the number and length of acyl chains and its phosphorylation state. InSalmonella entericaserovar Typhimurium, removal of the secondary laurate or myristate chain in lipid A results in bacterial attenuation and growth defectsin vitro. However, the roles of the two lipid A phosphate groups in bacterial virulence and immunogenicity remain unknown. Here, we used anS. TyphimuriummsbB pagL pagP lpxRmutant, carrying penta-acylated lipid A, as the parent strain to construct a series of mutants synthesizing 1-dephosphorylated, 4′-dephosphorylated, or nonphosphorylated penta-acylated lipid A. Dephosphorylated mutants exhibited increased sensitivity to deoxycholate and showed increased resistance to polymyxin B. Removal of both phosphate groups severely attenuated the mutants when administered orally to BALB/c mice, but the mutants colonized the lymphatic tissues and were sufficiently immunogenic to protect the host from challenge with wild-typeS. Typhimurium. Mice receivingS. Typhimurium with 1-dephosphorylated or nonphosphorylated penta-acylated lipid A exhibited reduced levels of cytokines. Attenuated and dephosphorylatedSalmonellavaccines were able to induce adaptive immunity against heterologous (PspA ofStreptococcus pneumoniae) and homologous antigens (lipopolysaccharide [LPS] and outer membrane proteins [OMPs]).

scholarly journals TheIn VitroRedundant Enzymes PurN and PurT Are Both Essential for Systemic Infection of Mice in Salmonella enterica Serovar Typhimurium

2016 ◽  
Vol 84 (7) ◽  
pp. 2076-2085 ◽  
Author(s):  
Lotte Jelsbak ◽  
Mie I. B. Mortensen ◽  
Mogens Kilstrup ◽  
John E. Olsen
Keyword(s):  
Salmonella Enterica ◽  
Single Gene ◽  
Systemic Infection ◽  
Gene Deletions ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Genes Encoding ◽  
Glycine Cleavage

Metabolic enzymes show a high degree of redundancy, and for that reason they are generally ignored in searches for novel targets for anti-infective substances. The enzymes PurN and PurT are redundantin vitroinSalmonella entericaserovar Typhimurium, in which they perform the third step of purine synthesis. Surprisingly, the results of the current study demonstrated that single-gene deletions of each of the genes encoding these enzymes caused attenuation (competitive infection indexes [CI] of <0.03) in mouse infections. While the ΔpurTmutant multiplied as fast as the wild-type strain in cultured J774A.1 macrophages, net multiplication of the ΔpurNmutant was reduced approximately 50% in 20 h. The attenuation of the ΔpurTmutant was abolished by simultaneous removal of the enzyme PurU, responsible for the formation of formate, indicating that the attenuation was related to formate accumulation or wasteful consumption of formyl tetrahydrofolate by PurU. In the process of further characterization, we disclosed that the glycine cleavage system (GCV) was the most important for formation of C1unitsin vivo(CI = 0.03 ± 0.03). In contrast, GlyA was the only important enzyme for the formation of C1unitsin vitro. The results with the ΔgcvTmutant further revealed that formation of serine by SerA and further conversion of serine into C1units and glycine by GlyA were not sufficient to ensure C1formation inS. Typhimuriumin vivo. The results of the present study call for reinvestigations of the concept of metabolic redundancy inS. Typhimuriumin vivo.

scholarly journals Identification and Characterization of Outer Membrane Vesicle-Associated Proteins in Salmonella enterica Serovar Typhimurium

2014 ◽  
Vol 82 (10) ◽  
pp. 4001-4010 ◽  
Author(s):  
Jaewoo Bai ◽  
Seul I Kim ◽  
Sangryeol Ryu ◽  
Hyunjin Yoon
Keyword(s):  
Outer Membrane ◽  
Virulence Factors ◽  
Salmonella Enterica ◽  
Minimal Medium ◽  
Environmental Changes ◽  
Outer Membrane Vesicles ◽  
Host Cells ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Associated Proteins

ABSTRACTSalmonella entericaserovar Typhimurium is a primary cause of enteric diseases and has acquired a variety of virulence factors during its evolution into a pathogen. Secreted virulence factors interact with commensal flora and host cells and enableSalmonellato survive and thrive in hostile environments. Outer membrane vesicles (OMVs) released from many Gram-negative bacteria function as a mechanism for the secretion of complex mixtures, including virulence factors. We performed a proteomic analysis of OMVs that were isolated under standard laboratory and acidic minimal medium conditions and identified 14 OMV-associated proteins that were observed in the OMV fraction isolated only under the acidic minimal medium conditions, which reproduced the nutrient-deficient intracellular milieu. The inferred roles of these 14 proteins were diverse, including transporter, enzyme, and transcriptional regulator. The absence of these proteins influencedSalmonellasurvival inside murine macrophages. Eleven of these proteins were predicted to possess secretion signal sequences at their N termini, and three (HupA, GlnH, and PhoN) of the proteins were found to be translocated into the cytoplasm of host cells. The comparative proteomic profiling of OMVs performed in this study revealed different protein compositions in the OMVs isolated under the two different conditions, which indicates that the OMV cargo depends on the growth conditions and provides a deeper insight into howSalmonellautilizes OMVs to adapt to environmental changes.

scholarly journals YhdP, TamB, and YdbH Are Redundant but Essential for Growth and Lipid Homeostasis of the Gram-Negative Outer Membrane

mBio ◽  
2021 ◽  
Author(s):  
Natividad Ruiz ◽  
Rebecca M. Davis ◽  
Sujeet Kumar
Keyword(s):  
Escherichia Coli ◽  
Outer Membrane ◽  
Lipid Homeostasis ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Content Type

Gram-negative bacteria like Escherichia coli are characterized by having two membranes. Systems required for the biogenesis of the Gram-negative outer membrane have been identified except for that required for the transport of newly synthesized phospholipids from the inner to the outer membrane.

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