scholarly journals The outer membrane protein OprQ and adherence of Pseudomonas aeruginosa to human fibronectin

Microbiology ◽  
2010 ◽  
Vol 156 (5) ◽  
pp. 1415-1423 ◽  
Author(s):  
Abraham Arhin ◽  
Cliff Boucher
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Membrane Protein ◽  
Nutrient Uptake ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
Wild Type ◽  
Insertional Inactivation ◽  
Human Fibronectin

Outer membrane proteins of the Gram-negative organism Pseudomonas aeruginosa play a significant role in membrane permeability, antibiotic resistance, nutrient uptake, and virulence in the infection site. In this study, we show that the P. aeruginosa outer membrane protein OprQ, a member of the OprD superfamily, is involved in the binding of human fibronectin (Fn). Some members of the OprD subfamily have been reported to be important in the uptake of nutrients from the environment. Comparison of wild-type and mutant strains of P. aeruginosa revealed that inactivation of the oprQ gene does not reduce the growth rate. Although it does not appear to be involved in nutrient uptake, an increased doubling time was reproducibly observed with the loss of OprQ in P. aeruginosa. Utilizing an oprQ–xylE transcriptional fusion, we determined that the PA2760 gene, encoding OprQ, was upregulated under conditions of decreased iron and magnesium. This upregulation appears to occur in early exponential phase. Insertional inactivation of PA2760 in the P. aeruginosa wild-type background did not produce a significant increase in resistance to any antibiotic tested, a phenotype that is typical of OprD family members. Interestingly, the in trans expression of OprQ in the ΔoprQ PAO1 mutant resulted in increased sensitivity to certain antibiotics. These findings suggest that OprQ is under dual regulation with other P. aeruginosa genes. Intact P. aeruginosa cells are capable of binding human Fn. We found that loss of OprQ resulted in a reduction of binding to plasmatic Fn in vitro. Finally, we present a discussion of the possible role of the P. aeruginosa outer membrane protein OprQ in adhesion to epithelial cells, thereby increasing colonization and subsequently enhancing lung destruction by P. aeruginosa.

scholarly journals Purification of the Major Outer Membrane Protein of Azospirillum brasilense, Its Affinity to Plant Roots, and Its Involvement in Cell Aggregation

2001 ◽  
Vol 14 (4) ◽  
pp. 555-561 ◽  
Author(s):  
Saul Burdman ◽  
Gabriella Dulguerova ◽  
Yaacov Okon ◽  
Edouard Jurkevitch
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Azospirillum Brasilense ◽  
Outer Membrane Proteins ◽  
Cell Aggregation ◽  
Major Outer Membrane Protein ◽  
Adhesion Assay ◽  
Fab Fragments

The major outer membrane protein (MOMP) of the nitrogen-fixing rhizobacterium Azospirillum brasilense strain Cd was purified and isolated by gel filtration, and antiserum against this protein was obtained. A screening of the binding of outer membrane proteins (OMPs) of A. brasilense to membrane-immobilized root extracts of various plant species revealed different affinities for the MOMP, with a stronger adhesion to extracts of cereals in comparison with legumes and tomatoes. Moreover, this protein was shown to bind to roots of different cereal seedlings in an in vitro adhesion assay. Incubation of A. brasilense cells with MOMP-antiserum led to fast agglutination, indicating that the MOMP is a surface-exposed protein. Cells incubated with Fab fragments obtained from purified MOMP-antiserum immunoglobulin G exhibited significant inhibition of bacterial aggregation as compared with controls. Bacteria preincubated with Fab fragments showed weaker adhesion to corn roots in comparison to controls without Fab fragments. These findings suggest that the A. brasilense MOMP acts as an adhesin involved in root adsorption and cell aggregation of this bacterium.

scholarly journals Heterogeneity among Helicobacter pylori Strains in Expression of the Outer Membrane Protein BabA

2004 ◽  
Vol 72 (6) ◽  
pp. 3429-3435 ◽  
Author(s):  
Ewa E. Hennig ◽  
Ray Mernaugh ◽  
Jennifer Edl ◽  
Ping Cao ◽  
Timothy L. Cover
Keyword(s):  
Helicobacter Pylori ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Recombinant Antibody ◽  
Wild Type ◽  
Single Chain ◽  
H Pylori ◽  
Different Strains

ABSTRACT The BabA adhesin of Helicobacter pylori is an outer membrane protein that binds to the fucosylated Lewis b histo-blood group antigen on the surface of gastric epithelial cells. We screened a phage-displayed ScFv (single-chain fragment variable) recombinant antibody library for antibodies reactive with a recombinant BabA fragment and identified two such antibodies. Each antibody recognized an ∼75-kDa protein present in wild-type H. pylori strain J99 but absent from an isogenic babA mutant strain. An immunoreactive BabA protein was detected by at least one of the antibodies in 18 (46%) of 39 different wild-type H. pylori strains and was detected more commonly in cagA-positive strains than in cagA-negative strains. Numerous amino acid polymorphisms were detected among BabA proteins expressed by different strains, with the greatest diversity occurring in the middle region of the proteins. Among the 18 strains that expressed a detectable BabA protein, there was considerable variation in the level of binding to Lewis b in vitro. Heterogeneity among H. pylori strains in expression of the BabA protein may be a factor that contributes to differing clinical outcomes among H. pylori-infected humans.

scholarly journals Lack of Outer Membrane Protein A Enhances the Release of Outer Membrane Vesicles and Survival ofVibrio choleraeand Suppresses Viability ofAcanthamoeba castellanii

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Soni Priya Valeru ◽  
Salah Shanan ◽  
Haifa Alossimi ◽  
Amir Saeed ◽  
Gunnar Sandström ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
Protein A ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Host Cells ◽  
Wild Type ◽  
Outer Membrane Protein A

Vibrio cholerae, the causative agent of the diarrhoeal disease cholera, survives in aquatic environments. The bacterium has developed a survival strategy to grow and survive insideAcanthamoeba castellanii. It has been shown thatV. choleraeexpresses outer membrane proteins as virulence factors playing a role in the adherence to interacted host cells. This study examined the role of outer membrane protein A (OmpA) and outer membrane vesicles (OMVs) in survival ofV. choleraealone and during its interaction withA. castellanii. The results showed that anOmpAmutant ofV. choleraesurvived longer than wild-typeV. choleraewhen cultivated alone. Cocultivation withA. castellaniienhanced the survival of both bacterial strains andOmpAprotein exhibited no effect on attachment, engulfment, and survival inside the amoebae. However, cocultivation of theOmpAmutant ofV. choleraedecreased the viability ofA. castellaniiand this bacterial strain released more OMVs than wild-typeV. cholerae. Surprisingly, treatment of amoeba cells with OMVs isolated from theOmpAmutant significantly decreased viable counts of the amoeba cells. In conclusion, the results might highlight a regulating rule forOmpAin survival ofV. choleraeand OMVs as a potent virulence factor for this bacterium towards eukaryotes in the environment.

scholarly journals Involvement of HxuC Outer Membrane Protein in Utilization of Hemoglobin by Haemophilus influenzae

2001 ◽  
Vol 69 (4) ◽  
pp. 2353-2363 ◽  
Author(s):  
Leslie D. Cope ◽  
Robert P. Love ◽  
Sarah E. Guinn ◽  
Andrei Gilep ◽  
Sergei Usanov ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Haemophilus Influenzae ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
Open Reading Frames ◽  
Triple Mutant ◽  
Nthi Strain ◽  
Free Heme

ABSTRACT Haemophilus influenzae can utilize different protein-bound forms of heme for growth in vitro. A previous study from this laboratory indicated that nontypeable Haemophilus influenzae (NTHI) strain N182 expressed three outer membrane proteins, designated HgbA, HgbB, and HgbC, that bound hemoglobin or hemoglobin-haptoglobin and were encoded by open reading frames (ORFs) that contained a CCAA nucleotide repeat. Testing of mutants expressing the HgbA, HgbB, and HgbC proteins individually revealed that expression of any one of these proteins was sufficient to allow wild-type growth with hemoglobin. In contrast, mutants that expressed only HgbA or HgbC grew significantly better with hemoglobin-haptoglobin than did a mutant expressing only HgbB. Construction of an isogenic hgbA hgbB hgbC mutant revealed that the absence of these three gene products did not affect the ability of NTHI N182 to utilize hemoglobin as a source of heme, although this mutant was severely impaired in its ability to utilize hemoglobin-haptoglobin. The introduction of atonB mutation into this triple mutant eliminated its ability to utilize hemoglobin, indicating that the pathway for hemoglobin utilization in the absence of HgbA, HgbB, and HgbC involved a TonB-dependent process. Inactivation in this triple mutant of thehxuC gene, which encodes a predicted TonB-dependent outer membrane protein previously shown to be involved in the utilization of free heme, resulted in loss of the ability to utilize hemoglobin. The results of this study reinforce the redundant nature of the heme acquisition systems expressed by H. influenzae.

scholarly journals Protection of Wild-Type and Severe Combined Immunodeficiency Mice against an Intranasal Challenge by Passive Immunization with Monoclonal Antibodies to the Chlamydia trachomatis Mouse Pneumonitis Major Outer Membrane Protein

2008 ◽  
Vol 76 (12) ◽  
pp. 5581-5587 ◽  
Author(s):  
Sukumar Pal ◽  
Jose Bravo ◽  
Ellena M. Peterson ◽  
Luis M. de la Maza
Keyword(s):  
Body Weight ◽  
Monoclonal Antibodies ◽  
Chlamydia Trachomatis ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Passive Immunization ◽  
Major Outer Membrane Protein ◽  
Wild Type

ABSTRACT Monoclonal antibodies (MAbs) to the Chlamydia trachomatis mouse pneumonitis (MoPn) major outer membrane protein (MOMP) were characterized for their ability to neutralize the infectivity of this organism in vitro and in vivo. One of the MAbs (MoPn-23) recognizes a nonlinear epitope in the MOMP, MAb MoPn-40 binds to a linear epitope in the variable domain 1 (VD1), and MAb MoPn-32 recognizes the chlamydial lipopolysaccharide. MAb MoPn-23 neutralized 50% of the infectivity of Chlamydia, as measured in vitro by using HAK (FcγIII−) and HeLa-229 (FcγIII+) cells at a concentration 100 times lower than MAb MoPn-40. MAb MoPn-32 had no neutralizing ability. In comparison to the control normal mouse immunoglobulin G, passive immunization of BALB/c mice with MAb MoPn-23 resulted in a highly significant protection against an intranasal (i.n.) challenge as determined by the change in body weight, the weight of the lungs, and the yield of Chlamydia inclusion-forming units (IFU) from the lungs. Passive immunization with MAb MoPn-40 resulted in a lower degree of protection, and MAb MoPn-32 afforded no protection. MAb MoPn-23 was also tested for its ability to protect wild-type (WT) and severe combined immunodeficient (SCID) C.B-17 mice against an i.n. challenge. Protection based on total body weight, lung weight, and yield of Chlamydia IFU was as effective in SCID as in WT C.B-17 mice. In conclusion, antibodies to MOMP can protect mice against a chlamydial infection in the presence or absence of T and B cells.

scholarly journals Safety and Immunogenicity of a Pseudomonas aeruginosa Hybrid Outer Membrane Protein F-I Vaccine in Human Volunteers

1999 ◽  
Vol 67 (3) ◽  
pp. 1461-1470 ◽  
Author(s):  
Erfan Mansouri ◽  
Josef Gabelsberger ◽  
Bernhard Knapp ◽  
Erika Hundt ◽  
Uwe Lenz ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Binding Assay ◽  
Significant Rise ◽  
Human Volunteers ◽  
Antibody Titers ◽  
Outer Membrane Protein F

ABSTRACT A hybrid protein [Met-Ala-(His)6OprF190–342-OprI21–83] consisting of the mature outer membrane protein I (OprI) and amino acids 190 to 342 of OprF of Pseudomonas aeruginosa was expressed in Escherichia coli and purified by Ni2+ chelate-affinity chromatography. After safety and pyrogenicity evaluations in animals, four groups of eight adult human volunteers were vaccinated intramuscularly three times at 4-week intervals and revaccinated 6 months later with either 500, 100, 50, or 20 μg of OprF-OprI adsorbed onto A1(OH)3. All vaccinations were well tolerated. After the first vaccination, a significant rise of antibody titers against P. aeruginosaOprF and OprI was measured in volunteers receiving the 100- or the 500-μg dose. After the second vaccination, significant antibody titers were measured for all groups. Elevated antibody titers against OprF and OprI could still be measured 6 months after the third vaccination. The capacity of the elicited antibodies to promote complement binding and opsonization could be demonstrated by a C1q-binding assay and by the in vitro opsonophagocytic uptake ofP. aeruginosa bacteria. These data support the continued development of an OprF-OprI vaccine for use in humans.

scholarly journals Dynamic periplasmic chaperone reservoir facilitates biogenesis of outer membrane proteins

2016 ◽  
Vol 113 (33) ◽  
pp. E4794-E4800 ◽  
Author(s):  
Shawn M. Costello ◽  
Ashlee M. Plummer ◽  
Patrick J. Fleming ◽  
Karen G. Fleming
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
Effective Rate ◽  
Stochastic Methods ◽  
Bacterial Physiology ◽  
Control Factors

Outer membrane protein (OMP) biogenesis is critical to bacterial physiology because the cellular envelope is vital to bacterial pathogenesis and antibiotic resistance. The process of OMP biogenesis has been studied in vivo, and each of its components has been studied in isolation in vitro. This work integrates parameters and observations from both in vivo and in vitro experiments into a holistic computational model termed “Outer Membrane Protein Biogenesis Model” (OMPBioM). We use OMPBioM to assess OMP biogenesis mathematically in a global manner. Using deterministic and stochastic methods, we are able to simulate OMP biogenesis under varying genetic conditions, each of which successfully replicates experimental observations. We observe that OMPs have a prolonged lifetime in the periplasm where an unfolded OMP makes, on average, hundreds of short-lived interactions with chaperones before folding into its native state. We find that some periplasmic chaperones function primarily as quality-control factors; this function complements the folding catalysis function of other chaperones. Additionally, the effective rate for the β-barrel assembly machinery complex necessary for physiological folding was found to be higher than has currently been observed in vitro. Overall, we find a finely tuned balance between thermodynamic and kinetic parameters maximizes OMP folding flux and minimizes aggregation and unnecessary degradation. In sum, OMPBioM provides a global view of OMP biogenesis that yields unique insights into this essential pathway.

scholarly journals Elimination of Channel-Forming Activity by Insertional Inactivation of the p13 Gene in Borrelia burgdorferi

2002 ◽  
Vol 184 (24) ◽  
pp. 6811-6819 ◽  
Author(s):  
Yngve Östberg ◽  
Marija Pinne ◽  
Roland Benz ◽  
Patricia Rosa ◽  
Sven Bergström
Keyword(s):  
Membrane Protein ◽  
Borrelia Burgdorferi ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Single Channel ◽  
Outer Membrane Proteins ◽  
Normal Growth ◽  
Growth Conditions ◽  
Targeted Mutagenesis ◽  
Insertional Inactivation

ABSTRACT P13 is a chromosomally encoded 13-kDa integral outer membrane protein of the Lyme disease agent, Borrelia burgdorferi. The aim of this study was to investigate the function of the P13 protein. Here, we inactivated the p13 gene by targeted mutagenesis and investigated the porin activities of outer membrane proteins by using lipid bilayer experiments. Channel-forming activity was lost in the p13 mutant compared to wild-type B. burgdorferi, indicating that P13 may function as a porin. We purified native P13 to homogeneity by fast performance liquid chromatography and demonstrated that pure P13 has channel-forming activity with a single-channel conductance in 1 M KCl of 3.5 nS, the same as the porin activity that was lost in the p13 mutant. Further characterization of the channel formed by P13 suggested that it is cation selective and voltage independent. In addition, no major physiological effects of the inactivated p13 gene could be detected under normal growth conditions. The inactivation of p13 is the first reported inactivation of a gene encoding an integral outer membrane protein in B. burgdorferi. Here, we describe both genetic and biophysical experiments indicating that P13 in B. burgdorferi is an outer membrane protein with porin activity.

scholarly journals Immunotherapy with IgY Antibodies toward Outer Membrane Protein F Protects Burned Mice against Pseudomonas aeruginosa Infection

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Fatemeh Norouzi ◽  
Bahador Behrouz ◽  
Mahya Ranjbar ◽  
Seyed Latif Mousavi Gargari
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Protective Efficacy ◽  
Passive Immunization ◽  
High Morbidity ◽  
Protein F ◽  
Outer Membrane Protein F

Burn patients with multidrug-resistant Pseudomonas aeruginosa infections commonly suffer from high morbidity and mortality, which present a major challenge to healthcare systems throughout the world. Outer membrane protein F (OprF), as a main outer membrane porin, is required for full virulence expression of P. aeruginosa. The aim of this study was to evaluate the protective efficacy of egg yolk-specific antibody (IgY) raised against recombinant OprF (r-OprF) protein in a murine burn model of infection. The hens were immunized with r-OprF, and anti-r-OprF IgY was purified using salt precipitation. Groups of mice were injected with different regimens of anti-OprF IgY or control IgY (C-IgY). Infections were caused by subcutaneous injection of P. aeruginosa strain PAO1 at the burn site. Mice were monitored for mortality for 5 days. The functional activity of anti-OprF IgY was determined by in vitro invasion assays. Immunotherapy with anti-OprF IgY resulted in a significant improvement in the survival of mice infected by P. aeruginosa from 25% to 87.5% compared with the C-IgY and PBS. The anti-OprF IgY decreased the invasion of P. aeruginosa PAO1 into the A549. Passive immunization with anti-OprF IgY led to an efficacious protection against P. aeruginosa burn infection in the burn model.

scholarly journals Involvement of a 43-kilodalton outer membrane protein in beta-lactam resistance of Shigella dysenteriae.

1997 ◽  
Vol 41 (10) ◽  
pp. 2302-2304 ◽  
Author(s):  
A K Kar ◽  
A S Ghosh ◽  
K Chauhan ◽  
J Ahamed ◽  
J Basu ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
Shigella Dysenteriae ◽  
Beta Lactam ◽  
Beta Lactams ◽  
Beta Lactam Antibiotics ◽  
Resistant Strains

A beta-lactam-sensitive strain (C152) of Shigella dysenteriae showed two major outer membrane proteins (OMPs) with M(r)s of 43,000 and 38,000, while the clinical isolate M2 lacked the 43,000-Mr OMP, which acted as a channel for beta-lactam antibiotics. Permeability of beta-lactams across the outer membrane (OM) of M2 was lower than that across the OM of C152. Mutants deficient in the 43-kDa OMP could be selected in vitro from strain C152 in the presence of cefoxitin. All beta-lactam-resistant strains were sensitive to imipenem.

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