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Literatura académica sobre el tema "Bacterial Outer Membrane Proteins Rabbits Syphilis Treponema pallidum"

Autor: Grafiati
Publicado: 4 de junio de 2021
Última modificación: 4 de febrero de 2022

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Artículos de revistas sobre el tema "Bacterial Outer Membrane Proteins Rabbits Syphilis Treponema pallidum"

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Brinkman, Mary Beth, Melanie A. McGill, Jonas Pettersson, Arthur Rogers, Petra Matějková, David Šmajs, George M. Weinstock, Steven J. Norris y Timothy Palzkill. "A Novel Treponema pallidum Antigen, TP0136, Is an Outer Membrane Protein That Binds Human Fibronectin". Infection and Immunity 76, n.º 5 (10 de marzo de 2008): 1848–57. http://dx.doi.org/10.1128/iai.01424-07.

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ABSTRACT The antigenicity, structural location, and function of the predicted lipoprotein TP0136 of Treponema pallidum subsp. pallidum were investigated based on previous screening studies indicating that anti-TP0136 antibodies are present in the sera of syphilis patients and experimentally infected rabbits. Recombinant TP0136 (rTP0136) protein was purified and shown to be strongly antigenic during human and experimental rabbit infection. The TP0136 protein was exposed on the surface of the bacterial outer membrane and bound to the host extracellular matrix glycoproteins fibronectin and laminin. In addition, the TP0136 open reading frame was shown to be highly polymorphic among T. pallidum subspecies and strains at the nucleotide and amino acid levels. Finally, the ability of rTP0136 protein to act as a protective antigen to subsequent challenge with infectious T. pallidum in the rabbit model of infection was assessed. Immunization with rTP0136 delayed ulceration but did not prevent infection or the formation of lesions. These results demonstrate that TP0136 is expressed on the outer membrane of the treponeme during infection and may be involved in attachment to host extracellular matrix components.
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Izard, Jacques, Christian Renken, Chyong-Ere Hsieh, Daniel C. Desrosiers, Star Dunham-Ems, Carson La Vake, Linda L. Gebhardt et al. "Cryo-Electron Tomography Elucidates the Molecular Architecture of Treponema pallidum, the Syphilis Spirochete". Journal of Bacteriology 191, n.º 24 (9 de octubre de 2009): 7566–80. http://dx.doi.org/10.1128/jb.01031-09.

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ABSTRACT Cryo-electron tomography (CET) was used to examine the native cellular organization of Treponema pallidum, the syphilis spirochete. T. pallidum cells appeared to form flat waves, did not contain an outer coat and, except for bulges over the basal bodies and widening in the vicinity of flagellar filaments, displayed a uniform periplasmic space. Although the outer membrane (OM) generally was smooth in contour, OM extrusions and blebs frequently were observed, highlighting the structure's fluidity and lack of attachment to underlying periplasmic constituents. Cytoplasmic filaments converged from their attachment points opposite the basal bodies to form arrays that ran roughly parallel to the flagellar filaments along the inner surface of the cytoplasmic membrane (CM). Motile treponemes stably attached to rabbit epithelial cells predominantly via their tips. CET revealed that T. pallidum cell ends have a complex morphology and assume at least four distinct morphotypes. Images of dividing treponemes and organisms shedding cell envelope-derived blebs provided evidence for the spirochete's complex membrane biology. In the regions without flagellar filaments, peptidoglycan (PG) was visualized as a thin layer that divided the periplasmic space into zones of higher and lower electron densities adjacent to the CM and OM, respectively. Flagellar filaments were observed overlying the PG layer, while image modeling placed the PG-basal body contact site in the vicinity of the stator-P-collar junction. Bioinformatics and homology modeling indicated that the MotB proteins of T. pallidum, Treponema denticola, and Borrelia burgdorferi have membrane topologies and PG binding sites highly similar to those of their well-characterized Escherichia coli and Helicobacter pylori orthologs. Collectively, our results help to clarify fundamental differences in cell envelope ultrastructure between spirochetes and gram-negative bacteria. They also confirm that PG stabilizes the flagellar motor and enable us to propose that in most spirochetes motility results from rotation of the flagellar filaments against the PG.
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Hazlett, Karsten R. O., David L. Cox, Marc Decaffmeyer, Michael P. Bennett, Daniel C. Desrosiers, Carson J. La Vake, Morgan E. La Vake et al. "TP0453, a Concealed Outer Membrane Protein of Treponema pallidum, Enhances Membrane Permeability". Journal of Bacteriology 187, n.º 18 (15 de septiembre de 2005): 6499–508. http://dx.doi.org/10.1128/jb.187.18.6499-6508.2005.

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ABSTRACT The outer membrane of Treponema pallidum, the noncultivable agent of venereal syphilis, contains a paucity of protein(s) which has yet to be definitively identified. In contrast, the outer membranes of gram-negative bacteria contain abundant immunogenic membrane-spanning β-barrel proteins mainly involved in nutrient transport. The absence of orthologs of gram-negative porins and outer membrane nutrient-specific transporters in the T. pallidum genome predicts that nutrient transport across the outer membrane must differ fundamentally in T. pallidum and gram-negative bacteria. Here we describe a T. pallidum outer membrane protein (TP0453) that, in contrast to all integral outer membrane proteins of known structure, lacks extensive β-sheet structure and does not traverse the outer membrane to become surface exposed. TP0453 is a lipoprotein with an amphiphilic polypeptide containing multiple membrane-inserting, amphipathic α-helices. Insertion of the recombinant, nonlipidated protein into artificial membranes results in bilayer destabilization and enhanced permeability. Our findings lead us to hypothesize that TP0453 is a novel type of bacterial outer membrane protein which may render the T. pallidum outer membrane permeable to nutrients while remaining inaccessible to antibody.
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Lewinski, Michael A., James N. Miller, Michael A. Lovett y David R. Blanco. "Correlation of Immunity in Experimental Syphilis with Serum-Mediated Aggregation of Treponema pallidum Rare Outer Membrane Proteins". Infection and Immunity 67, n.º 7 (1 de julio de 1999): 3631–36. http://dx.doi.org/10.1128/iai.67.7.3631-3636.1999.

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ABSTRACT We have previously shown by freeze-fracture electron microscopy that serum from infection-immune syphilitic rabbits aggregates the low-density membrane-spanning Treponema pallidum rare outer membrane proteins (TROMPs). The purpose of this study was to determine if a relationship could be demonstrated between acquired immunity in experimental rabbit syphilis, serum complement-dependent treponemicidal antibody, and antibody directed against TROMPs as measured by the aggregation of TROMP particles. Three groups of T. pallidum-infected rabbits were treated curatively with penicillin at 9 days, 30 days, and 6 months postinfection to generate various degrees of immunity to challenge reinfection. Sera from rabbits completely susceptible to localized and disseminated reinfection possessed a low titer of treponemicidal antibody (≤1:1 in killing ≥50% of a treponemal suspension) and showed a correspondingly low level of TROMP aggregation (16.5% of the total number of outer membrane particles counted) similar to normal serum controls (13.4%); the number of particles within these aggregates never exceeded three. Sera from partially immune rabbits, which were susceptible to local reinfection but had no evidence of dissemination, showed an increase in the titer of treponemicidal antibody (1:16) compared to the completely susceptible group (≤1:1). Although no significant increase was observed in the total number of TROMP particles aggregated (18.9%) compared to the number in controls (13.4%), approximately 15% of these aggregates did exhibit a significant increase in the number of particles per aggregate (4 to 5 particles) compared to controls (≤3 particles), indicating a measurable increase in anti-TROMP antibody. Finally, sera from rabbits completely immune to both local and disseminated reinfection possessed both high titers of treponemicidal antibody (1:128) and significant aggregation of TROMP (88.6%); approximately 50% of these aggregates contained four to six particles. The results indicate that complete immunity in experimental rabbit syphilis correlates with antibody that kills T. pallidumand aggregates TROMPs, suggesting that TROMPs are molecules which contribute to the development of acquired immunity.
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LaFond, Rebecca E. y Sheila A. Lukehart. "Biological Basis for Syphilis". Clinical Microbiology Reviews 19, n.º 1 (enero de 2006): 29–49. http://dx.doi.org/10.1128/cmr.19.1.29-49.2006.

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SUMMARY Syphilis is a chronic sexually transmitted disease caused by Treponema pallidum subsp. pallidum. Clinical manifestations separate the disease into stages; late stages of disease are now uncommon compared to the preantibiotic era. T. pallidum has an unusually small genome and lacks genes that encode many metabolic functions and classical virulence factors. The organism is extremely sensitive to environmental conditions and has not been continuously cultivated in vitro. Nonetheless, T. pallidum is highly infectious and survives for decades in the untreated host. Early syphilis lesions result from the host's immune response to the treponemes. Bacterial clearance and resolution of early lesions results from a delayed hypersensitivity response, although some organisms escape to cause persistent infection. One factor contributing to T. pallidum's chronicity is the paucity of integral outer membrane proteins, rendering intact organisms virtually invisible to the immune system. Antigenic variation of TprK, a putative surface-exposed protein, is likely to contribute to immune evasion. T. pallidum remains exquisitely sensitive to penicillin, but macrolide resistance has recently been identified in a number of geographic regions. The development of a syphilis vaccine, thus far elusive, would have a significant positive impact on global health.
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Giacani, Lorenzo, Stephanie L. Brandt, Wujian Ke, Tara B. Reid, Barbara J. Molini, Stefanie Iverson-Cabral, Giulia Ciccarese, Francesco Drago, Sheila A. Lukehart y Arturo Centurion-Lara. "Transcription of TP0126, Treponema pallidum Putative OmpW Homolog, Is Regulated by the Length of a Homopolymeric Guanosine Repeat". Infection and Immunity 83, n.º 6 (23 de marzo de 2015): 2275–89. http://dx.doi.org/10.1128/iai.00360-15.

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An effective mechanism for introduction of phenotypic diversity within a bacterial population exploits changes in the length of repetitive DNA elements located within gene promoters. This phenomenon, known as phase variation, causes rapid activation or silencing of gene expression and fosters bacterial adaptation to new or changing environments. Phase variation often occurs in surface-exposed proteins, and inTreponema pallidumsubsp.pallidum, the syphilis agent, it was reported to affect transcription of three putative outer membrane protein (OMP)-encoding genes. When theT. pallidumsubsp.pallidumNichols strain genome was initially annotated, the TP0126 open reading frame was predicted to include a poly(G) tract and did not appear to have a predicted signal sequence that might suggest the possibility of its being an OMP. Here we show that the initial annotation was incorrect, that this poly(G) is instead located within the TP0126 promoter, and that it varies in lengthin vivoduring experimental syphilis. Additionally, we show that TP0126 transcription is affected by changes in the poly(G) length consistent with regulation by phase variation.In silicoanalysis of the TP0126 open reading frame based on the experimentally identified transcriptional start site shortens this hypothetical protein by 69 amino acids, reveals a predicted cleavable signal peptide, and suggests structural homology with the OmpW family of porins. Circular dichroism of recombinant TP0126 supports structural homology to OmpW. Together with the evidence that TP0126 is fully conserved amongT. pallidumsubspecies and strains, these data suggest an important role for TP0126 inT. pallidumbiology and syphilis pathogenesis.
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Haynes, Austin M., Charmie Godornes, Wujian Ke y Lorenzo Giacani. "Evaluation of the Protective Ability of theTreponema pallidumsubsp.pallidumTp0126 OmpW Homolog in the Rabbit Model of Syphilis". Infection and Immunity 87, n.º 8 (10 de junio de 2019). http://dx.doi.org/10.1128/iai.00323-19.

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ABSTRACTIn silicoanalyses ofTreponema pallidumsubsp.pallidumgenomes and predicted proteomes to search for homologs of known bacterial outer membrane proteins (OMPs) led to the identification oftp0126as a gene encoding a putative member of the OmpW family of porins/virulence factors. Our previous investigations on the role of Tp0126 inT. pallidumbiology and syphilis pathogenesis showed that Tp0126 is fully conserved amongT. pallidumstrains and that transcription oftp0126is driven by σ70. These initial results pointed to a housekeeping function for this protein. We also demonstrated that a guanosine homopolymer of various lengths located between the −10 and −35 consensus sequences in thetp0126promoter modulates transcription consistently with phase variation, a mechanism that we also previously described for otherT. pallidumgenes encoding putative OMPs/virulence factors and that is often employed as a strategy for immune evasion. Circular dichroism spectra of recombinant Tp0126 also supported its structural homology with OmpW. Here we further investigated the humoral and cellular responses to Tp0126 during experimental and natural syphilis and the ability of Tp0126 to confer protection against syphilis in immunized rabbits. B-cell epitope mapping showed that compared to sera from experimentally infected animals, immunizations enhanced humoral immunity to sequences located in the putative Tp0126 surface-exposed loops, while phagocytosis assays showed that postimmunization sera opsonizedT. pallidum. Despite such promising results, no significant protection was seen following infectious challenge in immunized animals versus controls. Functional redundancy and phase variation might explain the lack of effectiveness of this vaccine candidate and/or design.
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Tesis sobre el tema "Bacterial Outer Membrane Proteins Rabbits Syphilis Treponema pallidum"

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Leader, Brandon Troy. "Immune responses during experimental Treponema pallidum infection /". Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/9277.

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Morgan, Cecilia A. "Treponema pallidum repeat protein K and heterologous protection against syphilis /". Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/9300.

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Chang, Po-Hsun. "Characterization of the Outer Membrane of Treponema Pallidum Subsp. Pallidum by Binding Studies Using Antibodies, Complement, and Host Serum Proteins". Thesis, University of North Texas, 1989. https://digital.library.unt.edu/ark:/67531/metadc798468/.

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The major goal of this study was to achieve sustained cultivation of virulent T. pallidum in vitro. The putatuive binding of host proteins to the outer membrane (OM) of intact, virulent T. pallidum subsp. pallidum has been investigated. A major breakthrough was the development of a filtration assay, usinglow protein-binding membrane filters, for the measurement of substances bound to or incorporated into th eOM of T. pallidum. This avoided the conventional manipulations which can damage the fragile OM of T. pallidum. Using this filtration assay, studies on the binding of host serum proteins demonstrated that intact treponemes did not bind host proteins as previously reported. It also indicated that previous studies were probably performed with damaged by this research. The studies on the binding of polyclonal and monoclonal antibodies to intact and detergent treated treponemes provided evidence of the low level binding of antibody to intact treponemes which was greatly enhanced but the removal of the outer membrane with 0.1% Triton X. This research research corroborated that of others which suggests that the outer membrane of T. pallidum contains very little protein or surface exposed antigen.
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