scholarly journals The LspB Protein Is Involved in the Secretion of the LspA1 and LspA2 Proteins by Haemophilus ducreyi

2004 ◽  
Vol 72 (4) ◽  
pp. 1874-1884 ◽  
Author(s):  
Christine K. Ward ◽  
Jason R. Mock ◽  
Eric J. Hansen
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Culture Supernatant ◽  
Cell Envelope ◽  
Rabbit Model ◽  
Haemophilus Ducreyi ◽  
Pcr Analysis ◽  
Supernatant Fluid ◽  
Reading Frame

ABSTRACT The LspA1 and LspA2 proteins of Haemophilus ducreyi 35000 are two very large macromolecules that can be detected in concentrated culture supernatant fluid. Both of these proteins exhibit homology with the N-terminal region of the Bordetella pertussis filamentous hemagglutinin (FHA), which is involved in secretion of the latter macromolecule. The lspA2 open reading frame is flanked upstream by a gene, lspB, that encodes a predicted protein with homology to the B. pertussis FhaC outer membrane protein that is involved in secretion of FHA across the outer membrane. The H. ducreyi lspB gene encodes a protein with a predicted molecular mass of 66,573 Da. Reverse transcription-PCR analysis suggested that the lspB gene was transcribed together with the lspA2 gene on a single mRNA transcript. Polyclonal H. ducreyi LspB antiserum reacted with a 64-kDa antigen present in the Sarkosyl-insoluble cell envelope fraction of H. ducreyi 35000, which indicated that the LspB protein is likely an outer membrane protein. Concentrated culture supernatant fluids from H. ducreyi lspB and lspA1 lspB mutants did not contain detectable LspA1 and detectable LspA2, respectively. However, complementation of the lspB mutant with the wild-type lspB gene on a plasmid restored LspB protein expression and resulted in release of detectable amounts of the LspA1 protein into culture supernatant fluid. When evaluated in the temperature-dependent rabbit model of infection, the lspB mutant was attenuated in the ability to cause lesions and was never recovered in a viable form from lesions. These results indicated that the H. ducreyi LspB protein is involved in secretion of the LspA1 and LspA2 proteins across the outer membrane.

scholarly journals Evaluation of an Isogenic Major Outer Membrane Protein-Deficient Mutant in the Human Model of Haemophilus ducreyi Infection

2000 ◽  
Vol 68 (5) ◽  
pp. 2602-2607 ◽  
Author(s):  
Robert E. Throm ◽  
Jaffar A. Al-Tawfiq ◽  
Kate R. Fortney ◽  
Barry P. Katz ◽  
Antoinette F. Hood ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Transcriptional Start Site ◽  
Haemophilus Ducreyi ◽  
Human Model ◽  
Deficient Mutant ◽  
Double Blind ◽  
Reading Frame ◽  
Porin Protein

ABSTRACT Haemophilus ducreyi expresses 2 OmpA homologs, designated MOMP and OmpA2, whose genes are arranged in tandem on the chromosome. Northern blot analysis indicated that momp andompA2 are transcribed independently. Sequences of themomp open reading frame (ORF) lacking the transcriptional start site were amplified by PCR, and an Ω-Km2 cassette was ligated into the ORF. A plasmid containing this construction was electroporated into H. ducreyi 35000HP, and an isogenic MOMP-deficient mutant (35000HP-SMS2) was generated by allele exchange. In Southern blotting, 35000HP-SMS2 contained one copy of the Ω-Km2 cassette inmomp. 35000HP and 35000HP-SMS2 had similar outer membrane protein (OMP) and lipooligosaccharide profiles and growth rates except for up-regulation of a putative porin protein in the mutant. Five subjects were inoculated with three doses of live 35000HP-SMS2 on one arm and two doses of live 35000HP and one dose of a heat-killed control on the other arm in a double-blind escalating dose-response trial. Pustules developed at 7 of 10 sites inoculated with 35000HP and at 6 of 15 sites inoculated with 35000HP-SMS2 (P = 0.14). 35000HP and 35000HP-SMS2 were recovered at similar rates from daily surface cultures and semiquantitative cultures. The data suggest that expression of MOMP is not required for pustule formation by H. ducreyi in the human model of infection.

scholarly journals Characterization of Haemophilus ducreyi cdtA, cdtB, and cdtC Mutants in In Vitro and In Vivo Systems

2001 ◽  
Vol 69 (9) ◽  
pp. 5626-5634 ◽  
Author(s):  
David A. Lewis ◽  
Marla K. Stevens ◽  
Jo L. Latimer ◽  
Christine K. Ward ◽  
Kaiping Deng ◽  
...  
Keyword(s):  
Hela Cells ◽  
Culture Supernatant ◽  
Cell Envelope ◽  
Rabbit Model ◽  
Haemophilus Ducreyi ◽  
Supernatant Fluid ◽  
E Coli

ABSTRACT Haemophilus ducreyi expresses a soluble cytolethal distending toxin (CDT) that is encoded by the cdtABC gene cluster and can be detected in culture supernatant fluid by its ability to kill HeLa cells. The cdtA, cdtB, and cdtCgenes of H. ducreyi were cloned independently into plasmid vectors, and their encoded proteins expressed singly or in various combinations in an Escherichia coli background. All three gene products had to be expressed in order for E. coli-derived culture supernatant fluids to demonstrate cytotoxicity for HeLa cells. Isogenic H. ducreyi cdtA and cdtB mutants were constructed and used in combination with the wild-type parent strain and a previously describedH. ducreyi cdtC mutant (M. K. Stevens, J. L. Latimer, S. R. Lumbley, C. K. Ward, L. D. Cope, T. Lagergard, and E. J. Hansen, Infect. Immun. 67:3900–3908, 1999) to determine the relative contributions of the CdtA, CdtB, and CdtC proteins to CDT activity. Expression of CdtA, CdtB, and CdtC appeared necessary for H. ducreyi-derived culture supernatant fluid to exhibit cytotoxicity for HeLa cells. Whole-cell sonicates and periplasmic extracts from the cdtB and cdtC mutants had no effect on HeLa cells, whereas these same fractions from a cdtA mutant had a very modest cytotoxic effect on these same human cells. CdtA appeared to be primarily associated with the H. ducreyi cell envelope, whereas both CdtB and CdtC were present primarily in the soluble fraction from sonicated cells. Both the cdtAmutant and the cdtB mutant were found to be fully virulent in the temperature-dependent rabbit model for experimental chancroid.

scholarly journals Identification by Subtractive Hybridization of a Novel Insertion Sequence Specific for Virulent Strains ofPorphyromonas gingivalis

1999 ◽  
Vol 67 (11) ◽  
pp. 5621-5625 ◽  
Author(s):  
Koichi Sawada ◽  
Susumu Kokeguchi ◽  
Hiroshi Hongyo ◽  
Satoko Sawada ◽  
Manabu Miyamoto ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Subtractive Hybridization ◽  
Open Reading Frame ◽  
Specific Marker ◽  
Avirulent Strain ◽  
Target Sequence ◽  
Dna Fragments ◽  
Reading Frame

ABSTRACT Subtractive hybridization was employed to isolate specific genes from virulent Porphyromonas gingivalis strains that are possibly related to abscess formation. The genomic DNA from the virulent strain P. gingivalis W83 was subtracted with DNA from the avirulent strain ATCC 33277. Three clones unique to strain W83 were isolated and sequenced. The cloned DNA fragments were 885, 369, and 132 bp and had slight homology with only Bacillus stearothermophilus IS5377, which is a putative transposase. The regions flanking the cloned DNA fragments were isolated and sequenced, and the gene structure around the clones was revealed. These three clones were located side-by-side in a gene reported as an outer membrane protein. The three clones interrupt the open reading frame of the outer membrane protein gene. This inserted DNA, consisting of three isolated clones, was designated IS1598, which was 1,396 bp (i.e., a 1,158-bp open reading frame) in length and was flanked by 16-bp terminal inverted repeats and a 9-bp duplicated target sequence. IS1598 was detected inP. gingivalis W83, W50, and FDC 381 by Southern hybridization. All three P. gingivalis strains have been shown to possess abscess-forming ability in animal models. However, IS1598 was not detected in avirulent strains of P. gingivalis, including ATCC 33277. The IS1598 may interrupt the synthesis of the outer membrane protein, resulting in changes in the structure of the bacterial outer membrane. The IS1598 isolated in this study is a novel insertion element which might be a specific marker for virulent P. gingivalisstrains.

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 Characterization of Outer Membrane Proteins in Chlamydia trachomatis LGV Serovar L2

2001 ◽  
Vol 183 (8) ◽  
pp. 2686-2690 ◽  
Author(s):  
Regina J. Tanzer ◽  
Thomas P. Hatch
Keyword(s):  
Chlamydia Trachomatis ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
Major Outer Membrane Protein ◽  
Developmental Cycle ◽  
Reading Frame

ABSTRACT We used a photoactivatable, lipophilic reagent, 3′-(trifluoromethyl)-3-(m-[125I]iodophenyl)diazirine, to label proteins in the outer membrane of elementary bodies ofChlamydia trachomatis LGV serovar L2 and mass spectrometry to identify the labeled proteins. The identified proteins were polymorphic outer membrane proteins E, G, and H, which were made late in the developmental cycle, the major outer membrane protein, and a mixture of 46-kDa proteins consisting of the open reading frame 623 protein and possibly a modified form of the major outer membrane protein.

scholarly journals Structure of BamA, an essential factor in outer membrane protein biogenesis

2014 ◽  
Vol 70 (6) ◽  
pp. 1779-1789 ◽  
Author(s):  
Reinhard Albrecht ◽  
Monika Schütz ◽  
Philipp Oberhettinger ◽  
Michaela Faulstich ◽  
Ivan Bermejo ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Cell Envelope ◽  
Significant Degree ◽  
State Function ◽  
E Coli ◽  
Functional Studies ◽  
C Terminus ◽  
Protein Biogenesis

Outer membrane protein (OMP) biogenesis is an essential process for maintaining the bacterial cell envelope and involves the β-barrel assembly machinery (BAM) for OMP recognition, folding and assembly. InEscherichia colithis function is orchestrated by five proteins: the integral outer membrane protein BamA of the Omp85 superfamily and four associated lipoproteins. To unravel the mechanism underlying OMP folding and insertion, the structure of theE. coliBamA β-barrel and P5 domain was determined at 3 Å resolution. These data add information beyond that provided in the recently published crystal structures of BamA fromHaemophilus ducreyiandNeisseria gonorrhoeaeand are a valuable basis for the interpretation of pertinent functional studies. In an `open' conformation,E. coliBamA displays a significant degree of flexibility between P5 and the barrel domain, which is indicative of a multi-state function in substrate transfer.E. coliBamA is characterized by a discontinuous β-barrel with impaired β1–β16 strand interactions denoted by only two connecting hydrogen bonds and a disordered C-terminus. The 16-stranded barrel surrounds a large cavity which implies a function in OMP substrate binding and partial folding. These findings strongly support a mechanism of OMP biogenesis in which substrates are partially folded inside the barrel cavity and are subsequently released laterally into the lipid bilayer.

Comparison of the cell envelope proteins of Micrococcus cryophilus with those of Neisseria and Branhamella species

1976 ◽  
Vol 22 (2) ◽  
pp. 309-312 ◽  
Author(s):  
R. R. B. Russell ◽  
I. J. McDonald
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Gel Electrophoresis ◽  
Cell Envelope ◽  
Polyacrylamide Gel Electrophoresis ◽  
Protein Composition ◽  
Polyacrylamide Gel ◽  
Outer Membranes ◽  
Branhamella Catarrhalis

In an attempt to elucidate the relation between Micrococcus cryophilus, Neisseria caviae, Neisseria ovis, and Branhamella catarrhalis, fractions derived from outer membranes of a strain of each organism were examined for protein composition by SDS – polyacrylamide gel electrophoresis. Micrococcus cryophilus outer membrane protein showed extensive similarities to that of N. ovis and contained a heat-modifiable protein which behaved almost identically with the corresponding bands previously shown to exist in N. caviae and N. oris. Branhamella catarrhalis protein was distinctly different from those of M. cryophilus and the two 'false neisserias' N. caviae and N. oris.

scholarly journals AN OUTER MEMBRANE PROTEIN OF NEISSERIA MENINGITIDIS GROUP B RESPONSIBLE FOR SEROTYPE SPECIFICITY

1974 ◽  
Vol 140 (1) ◽  
pp. 87-104 ◽  
Author(s):  
Carl E. Frasch ◽  
Emil C. Gotschlich
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Cell Envelope ◽  
Polyacrylamide Gel Electrophoresis ◽  
Gel Filtration ◽  
Major Outer Membrane Protein ◽  
Antigenic Specificity ◽  
Group B

Meningococcal groups B and C have been subdivided into a series of serotypes based upon the antigenic specificity of protein serotype antigens (STA). The purpose of these studies was to obtain the STA by gentle methods and determine its anatomic location in the meningococcal cell. The STA was extracted from group B meningococcal strains by either 0.2 M LiCl or 0.2 M CaCl2 and isolated from the extracts by gel filtration on Sepharose 6B or by pelleting the STA by centrifugation at 100,000 g. The isolated STA was a lipoprotein-lipopolysaccharide complex with a mol wt of approximately 4 x 106 daltons. Antisera prepared against the type 2 STA were bactericidal only for homologous serotype strains. The STA proved to be a constituent of the outer membrane of the cell envelope. This was shown by SDS-polyacrylamide gel electrophoresis (PAGE) of the isolated outer membrane and of the purified STA. The type 2 STA complex contains three principal proteins, one of which is predominant with a mol wt of 41,000 daltons. The type 2 STA was dissociated by Triton X-100 and separated by sucrose gradient isodensity centrifugation into two peaks. The denser peak (ρ = 1.26 g/cm3) contained the majority of the 41,000 dalton major outer membrane protein as shown by SDS-PAGE. This peak also contained the type 2 antigenic determinant. Thus the major outer membrane protein, extracted as part of a lipoprotein-lipopolysaccharide complex, contains the type 2 STA determinant.

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