scholarly journals A Live-Attenuated Pseudomonas aeruginosa Vaccine Elicits Outer Membrane Protein-Specific Active and Passive Protection against Corneal Infection

2006 ◽  
Vol 74 (2) ◽  
pp. 975-983 ◽  
Author(s):  
Tanweer S. Zaidi ◽  
Gregory P. Priebe ◽  
Gerald B. Pier
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Outer Membrane ◽  
Contact Lenses ◽  
Outer Membrane Proteins ◽  
Rabbit Antiserum ◽  
Passive Immunization ◽  
Infection Model ◽  
Corneal Infection ◽  
E Coli ◽  
Protective Antibodies

ABSTRACT Pseudomonas aeruginosa can cause sight-threatening corneal infections in humans, particularly those who wear contact lenses. We have previously shown that a live-attenuated P. aeruginosa vaccine given intranasally protected mice against acute lethal pneumonia in a lipopolysaccharide (LPS) serogroup-specific manner. In the current study, we evaluated the protective and therapeutic efficacies, as well as the target antigens, of this vaccine in a murine corneal infection model. C3H/HeN mice were nasally immunized with the vaccine (an aroA deletion mutant of strain PAO1, designated PAO1ΔaroA) or with Escherichia coli as a control and were challenged 3 weeks later by inoculating the scratch-injured cornea with P. aeruginosa. For passive prophylaxis and therapy, we utilized a serum raised in rabbits nasally immunized with PAO1ΔaroA or E. coli. Outcome measures included corneal pathology scores and, in some experiments, reductions in total and internalized bacterial CFU. We found that both active and passive immunization reduced corneal pathology scores after challenge with a variety of P. aeruginosa strains, including several serogroup-heterologous strains. Even when given therapeutically starting as late as 24 h after infection, the rabbit antiserum to PAO1ΔaroA was effective at reducing corneal pathology scores. Immunotherapy of established infections also reduced the numbers of total and internalized corneal P. aeruginosa bacteria. Experiments using absorbed sera showed that the protective antibodies are specific to outer membrane proteins. Thus, live-attenuated P. aeruginosa vaccines delivered nasally protect against corneal infections in mice and potentially can be used to prepare passive therapy reagents for the treatment of established P. aeruginosa corneal infections caused by diverse LPS serogroups.

scholarly journals Anti-Pseudomonas aeruginosa antibody detection in patients with bronchiectasis without cystic fibrosis

Thorax ◽  
2001 ◽  
Vol 56 (9) ◽  
pp. 669-674
Author(s):  
E Caballero ◽  
M-E Drobnic ◽  
M-T Pérez ◽  
J-M Manresa ◽  
A Ferrer ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Antibody Detection ◽  
Individual Bands ◽  
Diagnostic Usefulness ◽  
Group A ◽  
Group B

BACKGROUNDPseudomonas aeruginosa is a frequent cause of infection in patients with bronchiectasis. Differentiation between non-infected patients and those with different degrees of P aeruginosainfection could influence the management and prognosis of these patients. The diagnostic usefulness of serum IgG antibodies againstP aeruginosa outer membrane proteins was determined in patients with bronchiectasis without cystic fibrosis.METHODSFifty six patients were classified according to sputum culture into three groups: group A (n=18) with no P aeruginosain any sample; group B (n=18) with P aeruginosa alternating with other microorganisms; and group C (n=20) with P aeruginosa in all sputum samples. Each patient had at least three sputum cultures in the 6 months prior to serum collection. Detection of antibodies was performed by Western blot and their presence against 20 protein bands (10–121 kd) was assessed.RESULTSAntibodies to more than four bands in total or to five individual bands (36, 26, 22, 20 or 18 kd) differentiated group B from group A, while antibodies to a total of more than eight bands or to 10 individual bands (104, 69, 63, 56, 50, 44, 30, 25, 22, 13 kd) differentiated group C from group B. When discordant results between the total number of bands and the frequency of P aeruginosa isolation were obtained, the follow up of patients suggested that the former, in most cases, predicted chronic P aeruginosacolonisation.CONCLUSIONIn patients with bronchiectasis the degree of P aeruginosa infection can be determined by the number and type of outer membrane protein bands indicating which serum antibodies are present.

LamB, OmpA and OmpC are key altered outer membrane proteins in E. coli response to isopropanol

2011 ◽  
Vol 205 ◽  
pp. S216
Author(s):  
S. Wang ◽  
D. Zhang ◽  
X. Lin ◽  
H. Li ◽  
X. Peng
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
E Coli

scholarly journals Colicin Biology

2007 ◽  
Vol 71 (1) ◽  
pp. 158-229 ◽  
Author(s):  
Eric Cascales ◽  
Susan K. Buchanan ◽  
Denis Duché ◽  
Colin Kleanthous ◽  
Roland Lloubès ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Atomic Level ◽  
Fundamental Aspect ◽  
Genetic Determinants ◽  
Extracellular Medium ◽  
E Coli ◽  
Voltage Dependent ◽  
Tonb System ◽  
Specific Receptors

SUMMARY Colicins are proteins produced by and toxic for some strains of Escherichia coli. They are produced by strains of E. coli carrying a colicinogenic plasmid that bears the genetic determinants for colicin synthesis, immunity, and release. Insights gained into each fundamental aspect of their biology are presented: their synthesis, which is under SOS regulation; their release into the extracellular medium, which involves the colicin lysis protein; and their uptake mechanisms and modes of action. Colicins are organized into three domains, each one involved in a different step of the process of killing sensitive bacteria. The structures of some colicins are known at the atomic level and are discussed. Colicins exert their lethal action by first binding to specific receptors, which are outer membrane proteins used for the entry of specific nutrients. They are then translocated through the outer membrane and transit through the periplasm by either the Tol or the TonB system. The components of each system are known, and their implication in the functioning of the system is described. Colicins then reach their lethal target and act either by forming a voltage-dependent channel into the inner membrane or by using their endonuclease activity on DNA, rRNA, or tRNA. The mechanisms of inhibition by specific and cognate immunity proteins are presented. Finally, the use of colicins as laboratory or biotechnological tools and their mode of evolution are discussed.

BaeR participates in cephalosporins susceptibility by regulating the expression level of outer membrane proteins in Escherichia coli

2020 ◽  
Author(s):  
Shuaiyang Wang ◽  
Chunbo You ◽  
Fareed Qumar Memon ◽  
Geyin Zhang ◽  
Yawei Sun ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Membrane Proteins ◽  
Outer Membrane ◽  
Efflux Pump ◽  
Outer Membrane Proteins ◽  
Expression Level ◽  
Antibiotics Resistance ◽  
Dilution Method ◽  
Expression Levels ◽  
E Coli

Abstract The two-component system BaeSR participates in antibiotics resistance of Escherichia coli. To know whether the outer membrane proteins involve in the antibiotics resistance mediated by BaeSR, deletion of acrB was constructed and the recombined plasmid p-baeR was introduced into E. coli K12 and K12△acrB. Minimum inhibitory concentrations (MICs) of antibacterial agents were determined by 2-fold broth micro-dilution method. Gene expressions related with major outer membrane proteins and multidrug efflux pump-related genes were determined by real-time quantitative reverse transcription polymerase chain reaction. The results revealed that the MICs of K12ΔacrB to the tested drugs except for gentamycin and amikacin decreased 2- to 16.75-folds compared with those of K12. When BaeR was overexpressed, the MICs of K12ΔacrB/p-baeR to ceftiofur and cefotaxime increased 2.5- and 2-fold, respectively, compared with their corresponding that of K12△acrB. At the same time, the expression levels of ompC, ompF, ompW, ompA and ompX showed significant reduction in K12ΔacrB/p-baeR as compared with K12△acrB. Moreover, the expression levels of ompR, marA, rob and tolC also significantly ‘decreased’ in K12ΔacrB/p-baeR. These findings indicated that BaeR overproduction can decrease cephalosporins susceptibility in acrB-free E. coli by decreasing the expression level of outer membrane proteins.

scholarly journals Genetic Basis and Physiological Effects of Lipid A Hydroxylation in Pseudomonas aeruginosa PAO1

Pathogens ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 291 ◽  
Author(s):  
Alessandra Lo Sciuto ◽  
Matteo Cervoni ◽  
Roberta Stefanelli ◽  
Maria Concetta Spinnato ◽  
Alessandra Di Giamberardino ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Outer Membrane ◽  
Human Blood ◽  
Genetic Basis ◽  
Lipid A ◽  
Acyl Chain ◽  
Membrane Integrity ◽  
Physiological Role ◽  
Infection Model ◽  
Acyl Chains

Modifications of the lipid A moiety of lipopolysaccharide influence the physicochemical properties of the outer membrane of Gram-negative bacteria. Some bacteria produce lipid A with a single hydroxylated secondary acyl chain. This hydroxylation is catalyzed by the dioxygenase LpxO, and is important for resistance to cationic antimicrobial peptides (e.g., polymyxins), survival in human blood, and pathogenicity in animal models. The lipid A of the human pathogen Pseudomonas aeruginosa can be hydroxylated in both secondary acyl chains, but the genetic basis and physiological role of these hydroxylations are still unknown. Through the generation of single and double deletion mutants in the lpxO1 and lpxO2 homologs of P. aeruginosa PAO1 and lipid A analysis by mass spectrometry, we demonstrate that both LpxO1 and LpxO2 are responsible for lipid A hydroxylation, likely acting on different secondary acyl chains. Lipid A hydroxylation does not appear to affect in vitro growth, cell wall stability, and resistance to human blood or antibiotics in P. aeruginosa. In contrast, it is required for infectivity in the Galleria mellonella infection model, without relevantly affecting in vivo persistence. Overall, these findings suggest a role for lipid A hydroxylation in P. aeruginosa virulence that could not be directly related to outer membrane integrity.

scholarly journals Insight from TonB Hybrid Proteins into the Mechanism of Iron Transport through the Outer Membrane

2008 ◽  
Vol 190 (11) ◽  
pp. 4001-4016 ◽  
Author(s):  
Wallace A. Kaserer ◽  
Xiaoxu Jiang ◽  
Qiaobin Xiao ◽  
Daniel C. Scott ◽  
Matthew Bauler ◽  
...  
Keyword(s):  
Amino Acids ◽  
Outer Membrane ◽  
Cell Envelope ◽  
Outer Membrane Proteins ◽  
Binding Motif ◽  
Inner Membrane ◽  
E Coli ◽  
Hybrid Proteins ◽  
C Terminus ◽  
N Terminus

ABSTRACT We created hybrid proteins to study the functions of TonB. We first fused the portion of Escherichia coli tonB that encodes the C-terminal 69 amino acids (amino acids 170 to 239) of TonB downstream from E. coli malE (MalE-TonB69C). Production of MalE-TonB69C in tonB + bacteria inhibited siderophore transport. After overexpression and purification of the fusion protein on an amylose column, we proteolytically released the TonB C terminus and characterized it. Fluorescence spectra positioned its sole tryptophan (W213) in a weakly polar site in the protein interior, shielded from quenchers. Affinity chromatography showed the binding of the TonB C-domain to other proteins: immobilized TonB-dependent (FepA and colicin B) and TonB-independent (FepAΔ3-17, OmpA, and lysozyme) proteins adsorbed MalE-TonB69C, revealing a general affinity of the C terminus for other proteins. Additional constructions fused full-length TonB upstream or downstream of green fluorescent protein (GFP). TonB-GFP constructs had partial functionality but no fluorescence; GFP-TonB fusion proteins were functional and fluorescent. The activity of the latter constructs, which localized GFP in the cytoplasm and TonB in the cell envelope, indicate that the TonB N terminus remains in the inner membrane during its biological function. Finally, sequence analyses revealed homology in the TonB C terminus to E. coli YcfS, a proline-rich protein that contains the lysin (LysM) peptidoglycan-binding motif. LysM structural mimicry occurs in two positions of the dimeric TonB C-domain, and experiments confirmed that it physically binds to the murein sacculus. Together, these findings infer that the TonB N terminus remains associated with the inner membrane, while the downstream region bridges the cell envelope from the affinity of the C terminus for peptidoglycan. This architecture suggests a membrane surveillance model of action, in which TonB finds occupied receptor proteins by surveying the underside of peptidoglycan-associated outer membrane proteins.

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