scholarly journals Meningococcal Outer Membrane Protein NhhA Is Essential for Colonization and Disease by Preventing Phagocytosis and Complement Attack

2008 ◽  
Vol 76 (11) ◽  
pp. 5412-5420 ◽  
Author(s):  
Hong Sjölinder ◽  
Jens Eriksson ◽  
Lisa Maudsdotter ◽  
Helena Aro ◽  
Ann-Beth Jonsson
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Bacterial Colonization ◽  
Membrane Attack Complex ◽  
Rapid Onset ◽  
Bacterial Attachment ◽  
High Morbidity ◽  
Bacterial Survival

ABSTRACT Neisseria meningitidis is a leading cause of meningitis and septicemia worldwide, with a rapid onset of disease and a high morbidity and mortality. NhhA is a meningococcal outer membrane protein included in the family of trimeric autotransporter adhesins. The protein binds to the extracellular matrix proteins heparan sulfate and laminin and facilitates attachment to host epithelial cells. In this study, we show that NhhA is essential for bacterial colonization of the nasopharyngeal mucosa in a murine model of meningococcal disease. Successful colonization depends on bacterial attachment but also to the capacity to overcome innate host immune responses. We found that NhhA protected bacteria from phagocytosis, which is important for the mucosal survival of bacteria. In addition, NhhA mediated extensive serum resistance that increased bacterial survival in blood and promoted lethal sepsis. The presence of NhhA protected bacteria from complement-mediated killing by preventing the deposition of the membrane attack complex. Taken together, the results of this work reveal that NhhA inhibits phagocytosis and protects bacteria against complement-mediated killing, which enhances both nasal colonization and the development of sepsis in vivo.

scholarly journals An ArsR Transcriptional Regulator Facilitates Brucella sp. Survival via Regulating Self and Outer Membrane Protein

2021 ◽  
Vol 22 (19) ◽  
pp. 10860
Author(s):  
Feijie Zhi ◽  
Dong Zhou ◽  
Jialu Chen ◽  
Jiaoyang Fang ◽  
Weifang Zheng ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Metal Ion ◽  
Target Genes ◽  
Ion Homeostasis ◽  
Infection Model ◽  
Bacterial Survival ◽  
Metal Ion Homeostasis

The arsenic acid-resistant (ArsR) family transcriptional regulators are widely distributed in microorganisms, including in the facultative intracellular pathogen Brucella spp. ArsR proteins are implicated in numerous biological processes. However, the specific roles of ArsR family members in Brucella remain obscure. Here, we show that ArsR6 (BSS2_RS07325) is required for Brucella survival both under heat, oxidative, and osmotic stress and in a murine infection model in vivo. RNA-seq and ChIP-seq reveal that 34 potential target genes for ArsR6 protein were identified, among which eight genes were up-regulated and 26 genes were down-regulated, including outer membrane protein 25D (Omp25D). ArsR6 autoregulates its own expression to maintain bacterial intracellular Cu/Ni homeostasis to benefit bacterial survival in hostile environments. Moreover, ArsR6 also regulates the production of virulence factor Omp25D, which is important for the survival of Brucella under stress conditions. Significantly, Omp25D deletion strain attenuated in a murine infection model in vivo. Altogether, our findings reveal a unique mechanism in which the ArsR family member ArsR6 autoregulates its expression and also modulates Omp25D expression to maintain metal ion homeostasis and virulence in Brucella.

scholarly journals Localization of Haemophilus ducreyi at the Pustular Stage of Disease in the Human Model of Infection

2000 ◽  
Vol 68 (4) ◽  
pp. 2309-2314 ◽  
Author(s):  
Margaret E. Bauer ◽  
Stanley M. Spinola
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Human Subjects ◽  
Haemophilus Ducreyi ◽  
Human Model ◽  
Stage Of Disease ◽  
The One ◽  
Secondary Antibodies

ABSTRACT To localize Haemophilus ducreyi in vivo, human subjects were experimentally infected with H. ducreyi until they developed a painful pustule or for 14 days. Lesions were biopsied, and biopsy samples were fixed in 4% paraformaldehyde, and cryosectioned. Sections were stained with polyclonal anti-H. ducreyi antiserum or H. ducreyi-specific monoclonal antibodies (MAbs) and fluorescently tagged secondary antibodies and examined by confocal microscopy. We identified H. ducreyi in 16 of 18 pustules but did not detect bacteria in the one papule examined. H. ducreyi was observed as individual cells and in clumps or chains. Staining with MAbs 2D8, 5C9, 3B9, 2C7, and 9D12 demonstrated that H. ducreyi expresses the major pilus subunit, FtpA, the 28-kDa outer membrane protein Hlp, the 18-kDa outer membrane protein PAL, and the major outer membrane protein (MOMP) or OmpA2 in vivo. By dual staining with polyclonal anti-H. ducreyi antiserum and MAbs that recognize human skin components, we observed bacteria within the neutrophilic infiltrates of all positively staining pustules and in the dermis of 10 of 16 pustules. We were unable to detect bacteria associated with keratinocytes in the samples examined. The data suggest that H. ducreyi is found primarily in association with neutrophils and in the dermis at the pustular stage of disease in the human model of infection.

scholarly journals In Vivo Transfer of Plasmid-Encoded ACC-1 AmpC from Klebsiella pneumoniae to Escherichia coli in an Infant and Selection of Impermeability to Imipenem in K. pneumoniae

2005 ◽  
Vol 49 (8) ◽  
pp. 3562-3565 ◽  
Author(s):  
Philippe Bidet ◽  
Béatrice Burghoffer ◽  
Valérie Gautier ◽  
Naïma Brahimi ◽  
Patricia Mariani-Kurkdjian ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Membrane Protein ◽  
Klebsiella Pneumoniae ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Major Outer Membrane Protein ◽  
In Vivo Selection ◽  
Selection Of

ABSTRACT We describe in vivo selection of a Klebsiella pneumoniae strain with diminished imipenem susceptibility attributable to plasmid-encoded ACC-1 β-lactamase production and loss of a 36-kDa major outer membrane protein, together with transfer of this plasmid from K. pneumoniae to Escherichia coli in a Tunisian infant.

scholarly journals Characterization of Specific Immune Responses of Mice Inoculated with Recombinant Vaccinia Virus Expressing an 18-Kilodalton Outer Membrane Protein of Brucella abortus

2000 ◽  
Vol 7 (1) ◽  
pp. 114-118 ◽  
Author(s):  
Ramesh Vemulapalli ◽  
Silvio Cravero ◽  
Christine L. Calvert ◽  
Thomas E. Toth ◽  
Nammalwar Sriranganathan ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Vaccinia Virus ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Brucella Abortus ◽  
Virulent Strain ◽  
Shuttle Vector ◽  
Protein Fusion

ABSTRACT Using the shuttle vector pMCO2 and the vaccinia virus wild-type WR strain, we constructed a recombinant virus expressing an 18-kDa outer membrane protein of Brucella abortus. BALB/c mice inoculated with this virus produced 18-kDa protein-specific antibodies, mostly of immunoglobulin G2a isotype, and in vitro stimulation of splenocytes from these mice with purified maltose binding protein–18-kDa protein fusion resulted in lymphocyte proliferation and gamma interferon production. However, these mice were not protected against a challenge with the virulent strain B. abortus2308. Disruption of the 18-kDa protein's gene in vaccine strainB. abortus RB51 did not affect either the strain's protective capabilities or its in vivo attenuation characteristics. These observations suggest that the 18-kDa protein plays no role in protective immunity.

scholarly journals Metalloadsorption by Escherichia coliCells Displaying Yeast and Mammalian Metallothioneins Anchored to the Outer Membrane Protein LamB

1998 ◽  
Vol 180 (9) ◽  
pp. 2280-2284 ◽  
Author(s):  
Carolina Sousa ◽  
Pavel Kotrba ◽  
Tomas Ruml ◽  
Angel Cebolla ◽  
Víctor De Lorenzo
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Metal Binding ◽  
Wild Type ◽  
Lambda Phage ◽  
E Coli ◽  
Hybrid Proteins ◽  
Mammalian Metallothioneins

ABSTRACT Yeast (CUP1) and mammalian (HMT-1A) metallothioneins (MTs) have been efficiently expressed in Escherichia coli as fusions to the outer membrane protein LamB. A 65-amino-acid sequence from the CUP1 protein of Saccharomyces cerevisiae (yeast [Y] MT) was genetically inserted in permissive site 153 of the LamB sequence, which faces the outer medium. A second LamB fusion at position 153 was created with 66 amino acids recruited from the form of human (H) MT that is predominant in the adipose tissue, HMT-1A. Both LamB153-YMT and LamB153-HMT hybrids were produced in vivo as full-length proteins, without any indication of instability or proteolytic degradation. Each of the two fusion proteins was functional as the port of entry of lambda phage variants, suggesting maintenance of the overall topology of the wild-type LamB. Expression of the hybrid proteins in vivo multiplied the natural ability of E. colicells to bind Cd2+ 15- to 20-fold, in good correlation with the number of metal-binding centers contributed by the MT moiety of the fusions.

scholarly journals Roles of the Carboxy-Terminal Half of Pseudomonas aeruginosa Major Outer Membrane Protein OprF in Cell Shape, Growth in Low-Osmolarity Medium, and Peptidoglycan Association

1998 ◽  
Vol 180 (14) ◽  
pp. 3556-3562 ◽  
Author(s):  
Eileen G. Rawling ◽  
Fiona S. L. Brinkman ◽  
Robert E. W. Hancock
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Membrane Protein ◽  
Protein Expression ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Cell Shape ◽  
Cell Length ◽  
C Terminus ◽  
N Terminus

ABSTRACT OprF, the major outer membrane protein of Pseudomonas aeruginosa, is multifunctional in that it can act as a nonspecific porin, plays a role in the maintenance of cell shape, and is required for growth in a low-osmolarity environment. The latter two structural roles of OprF, and OprF’s association with the peptidoglycan, have been proposed to be localized in the carboxy terminus of the protein, based on this region’s similarity to members of the OmpA family of proteins. To determine if this is correct, we constructed a series of C-terminally truncated OprF derivatives and examined their effects on P. aeruginosa cell length and growth in low-osmolarity medium. While the C terminus of OprF was required for wild-type cell length and growth in low-osmolarity medium, expression of the N terminus (first 163 amino acids [aa]) also influenced these phenotypes (compared with OprF deficiency). The first 154 to 164 aa of OprF seemed required for stable protein expression, consistent with the existence of a β-barrel domain in the N terminus of OprF. Greater than 215 aa of the protein were required for strong peptidoglycan association, confirming that residues in the C-terminal end of OprF are required for peptidoglycan binding. OprF deficiency did not affect the in vivo growth of an OprF-deficient strain in a mouse chamber model. Collectively, these data suggest that the C terminus of OprF plays a role in cell length, growth of P. aeruginosa in low-osmolarity media (but not in vivo), and peptidoglycan association, while the N terminus has an influence on the first two characteristics and is additionally important for stable protein expression.

scholarly journals Methylation and in vivo expression of the surface-exposed Leptospira interrogans outer-membrane protein OmpL32

Microbiology ◽  
2012 ◽  
Vol 158 (3) ◽  
pp. 622-635 ◽  
Author(s):  
Azad Eshghi ◽  
Marija Pinne ◽  
David A. Haake ◽  
Richard L. Zuerner ◽  
Ami Frank ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Leptospira Interrogans ◽  
In Vivo Expression

scholarly journals LipL32 Is an Extracellular Matrix-Interacting Protein of Leptospira spp. and Pseudoalteromonas tunicata

2008 ◽  
Vol 76 (5) ◽  
pp. 2063-2069 ◽  
Author(s):  
David E. Hoke ◽  
Suhelen Egan ◽  
Paul A. Cullen ◽  
Ben Adler
Keyword(s):  
Extracellular Matrix ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
Major Outer Membrane Protein ◽  
Interacting Proteins ◽  
Orthologous Protein ◽  
Pseudoalteromonas Tunicata

ABSTRACT LipL32 is the major outer membrane protein in pathogenic Leptospira. It is highly conserved throughout pathogenic species and is expressed in vivo during human infection. While these data suggest a role in pathogenesis, a function for LipL32 has not been defined. Outer membrane proteins of gram-negative bacteria are the first line of molecular interaction with the host, and many have been shown to bind host extracellular matrix (ECM). A search for leptospiral ECM-interacting proteins identified the major outer membrane protein, LipL32. To verify this finding, recombinant LipL32 was expressed in Escherichia coli and was found to bind Matrigel ECM and individual components of ECM, including laminin, collagen I, and collagen V. Likewise, an orthologous protein found in the genome of Pseudoalteromonas tunicata strain D2 was expressed and found to be functionally similar and immunologically cross-reactive. Lastly, binding activity was mapped to the C-terminal 72 amino acids. These studies show that LipL32 and an orthologous protein in P. tunicata are immunologically cross-reactive and function as ECM-interacting proteins via a conserved C-terminal region.

scholarly journals Refolding of Escherichia coli outer membrane protein F in detergent creates LPS-free trimers and asymmetric dimers

2005 ◽  
Vol 392 (2) ◽  
pp. 375-381 ◽  
Author(s):  
Virak Visudtiphole ◽  
Matthew B. Thomas ◽  
David A. Chalton ◽  
Jeremy H. Lakey
Keyword(s):  
Escherichia Coli ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Single Molecule ◽  
Outer Membrane Protein ◽  
Structural Integrity ◽  
Protein F ◽  
Outer Membrane Protein F

The Escherichia coli OmpF (outer-membrane protein F; matrix porin) is a homotrimeric β-barrel and a member of the bacterial porin superfamily. It is the best characterized porin protein, but has resisted attempts to refold it efficiently in vitro. In the present paper, we report the discovery of detergent-based folding conditions, including dodecylglucoside, which can create pure samples of trimeric OmpF. Whereas outer membrane LPS (lipopolysaccharide) is clearly required for in vivo folding, the artificially refolded and LPS-free trimer has properties identical with those of the outer-membrane-derived form. Thus LPS is not required either for in vitro folding or for structural integrity. Dimeric forms of OmpF have been observed in vivo and are proposed to be folding intermediates. In vitro, dimers occur transiently in refolding of trimeric OmpF and, in the presence of dodecylmaltoside, pure dimer can be prepared. This form has less β-structure by CD and shows lower thermal stability than the trimer. Study of these proteins at the single-molecule level is possible because each OmpF subunit forms a distinct ion channel. Whereas each trimer contains three channels of equal conductance, each dimer always contains two distinct channel sizes. This provides clear evidence that the two otherwise identical monomers adopt different structures in the dimer and indicates that the asymmetric interaction, characteristic of C3 symmetry, is formed at the dimer stage. This asymmetric dimer may be generally relevant to the folding of oligomeric proteins with odd numbers of subunits such as aspartate transcarbamoylase.

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