scholarly journals Outer Membrane Proteins BB0405 and BB0406 Are Immunogenic, but Only BB0405 Is Required for Borrelia burgdorferi Infection

2016 ◽  
Vol 85 (2) ◽  
Author(s):  
Binu Shrestha ◽  
Melisha R. Kenedy ◽  
Darrin R. Akins
Keyword(s):  
Borrelia Burgdorferi ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Human Infection ◽  
Factor H ◽  
Serum Resistance ◽  
Gene Encoding ◽  
Content Type ◽  
Protein Factor

ABSTRACT We recently identified the Borrelia burgdorferi outer membrane protein (OMP) BB0406 and found that the gene encoding this OMP was cotranscribed with the gene encoding the OMP BB0405. Interestingly, BB0405 and BB0406 share 59% similarity and are grouped into the same B. burgdorferi paralogous gene family. Given their overall similarity, it is plausible that both OMPs have similar or overlapping functions in this pathogenic spirochete. BB0405 was recently shown to be required for mammalian infection despite the observations that BB0405 is poorly immunogenic and not recognized during mouse or human infection. BB0405 orthologs have also been shown to bind the complement regulator protein factor H. Therefore, to better elucidate the role of BB0405 and its paralog BB0406 during infection and in serum resistance, we examined both proteins in animal infection, factor H binding, and serum sensitivity assays. Our combined results suggest that BB0405- and BB0406-specific antibodies are borreliacidal and that both OMPs are immunogenic during nonhuman primate infection. Additionally, while BB0405 was found to be required for establishing mouse infection, BB0406 was not found to be essential for infectivity. In contrast to data from previous reports, however, neither OMP was found to bind human factor H or to be required for enhancing serum resistance of B. burgdorferi in vitro.

scholarly journals Serum resistance ofAcinetobacter baumanniithrough the binding of factor H to outer membrane proteins

2009 ◽  
Vol 301 (2) ◽  
pp. 224-231 ◽  
Author(s):  
Sang Woo Kim ◽  
Chul Hee Choi ◽  
Dong Chan Moon ◽  
Jong Sook Jin ◽  
Jung Hwa Lee ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Factor H ◽  
Serum Resistance

scholarly journals Catecholamine-Modulated Novel Surface-Exposed Adhesin LIC20035 ofLeptospiraspp. Binds Host Extracellular Matrix Components and Is Recognized by the Host during Infection

2017 ◽  
Vol 84 (6) ◽  
Author(s):  
Karukriti Kaushik Ghosh ◽  
Aman Prakash ◽  
Vinayagamurthy Balamurugan ◽  
Manish Kumar
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Membrane Surface ◽  
Outer Membrane Proteins ◽  
Extracellular Matrices ◽  
Content Type ◽  
Extracellular Matrix Components ◽  
Gene Transcripts ◽  
Host Tissues

ABSTRACTIn this study, the effect of the host stress hormone catecholamine onLeptospiragene transcripts encoding outer membrane proteins was investigated. There was no impact of catecholamine supplementation on thein vitrogrowth pattern ofLeptospira interrogans; however, 7 genes out of 41 were differentially transcribed, and the effect was reversed to the basal level in the presence of the antagonist propranolol. Comprehensive analysis of one of the differentially regulated proteins, LIC20035 (in serovar Copenhageni)/LB047 (in serovar Lai) (due to catecholamine supplementation), revealed immunogenicity and ability to adhere to host extracellular matrices. Protease accessibility assay and phase partition of integral membrane proteins ofLeptospirashowed LIC20035/LB047 to be an outer membrane surface-exposed protein. The recombinant LIC20035 protein can be serologically detected using human/bovine sera positive for leptospirosis. Moreover, the recombinant LIC20035 can bind to diverse host extracellular matrices, with a higher affinity toward collagen and chondroitin sulfate.IMPORTANCELeptospirosis is a neglected tropical disease of global importance. This study aimed to identify outer membrane proteins of pathogenicLeptospiraresponding to host chemical signals like catecholamines, with the potential to serve as virulence factors, new serodiagnostic antigens, and vaccine candidates. This study mimicked the plausible means by whichLeptospiraduring infection and hormonal stress intercepts host catecholamines to disseminate in host tissues.

scholarly journals Borrelia burgdorferi Needs Chemotaxis To Establish Infection in Mammals and To Accomplish Its Enzootic Cycle

2012 ◽  
Vol 80 (7) ◽  
pp. 2485-2492 ◽  
Author(s):  
Ching Wooen Sze ◽  
Kai Zhang ◽  
Toru Kariu ◽  
Utpal Pal ◽  
Chunhao Li
Keyword(s):  
Borrelia Burgdorferi ◽  
Capillary Tube ◽  
Virulent Strain ◽  
Gene Encoding ◽  
Content Type ◽  
Immunodeficient Mice ◽  
Passage Number ◽  
Low Passage ◽  
Enzootic Cycle

ABSTRACTBorrelia burgdorferi, the causative agent of Lyme disease, can be recovered from different organs of infected animals and patients, indicating that the spirochete is very invasive. Motility and chemotaxis contribute to the invasiveness ofB. burgdorferiand play important roles in the process of the disease. Recent reports have shown that motility is required for establishing infection in mammals. However, the role of chemotaxis in virulence remains elusive. Our previous studies showed thatcheA2, a gene encoding a histidine kinase, is essential for the chemotaxis ofB. burgdorferi. In this report, thecheA2gene was inactivated in a low-passage-number virulent strain ofB. burgdorferi. In vitroanalyses (microscopic observations, computer-based bacterial tracking analysis, swarm plate assays, and capillary tube assays) showed that thecheA2mutant failed to reverse and constantly ran in one direction; the mutant was nonchemotactic to attractants. Mouse needle infection studies showed that thecheA2mutant failed to infect either immunocompetent or immunodeficient mice and was quickly eliminated from the initial inoculation sites. Tick-mouse infection studies revealed that although the mutant was able to survive in ticks, it failed to establish a new infection in mice via tick bites. The altered phenotypes were completely restored when the mutant was complemented. Collectively, these data demonstrate thatB. burgdorferineeds chemotaxis to establish mammalian infection and to accomplish its natural enzootic cycle.

scholarly journals Phosphate Groups of Lipid A Are Essential for Salmonella enterica Serovar Typhimurium Virulence and Affect Innate and Adaptive Immunity

2012 ◽  
Vol 80 (9) ◽  
pp. 3215-3224 ◽  
Author(s):  
Qingke Kong ◽  
David A. Six ◽  
Qing Liu ◽  
Lillian Gu ◽  
Shifeng Wang ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Adaptive Immunity ◽  
Salmonella Enterica ◽  
Lipid A ◽  
Outer Membrane Proteins ◽  
Polymyxin B ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Phosphate Groups

ABSTRACTLipid A is a key component of the outer membrane of Gram-negative bacteria and stimulates proinflammatory responses via the Toll-like receptor 4 (TLR4)-MD2-CD14 pathway. Its endotoxic activity depends on the number and length of acyl chains and its phosphorylation state. InSalmonella entericaserovar Typhimurium, removal of the secondary laurate or myristate chain in lipid A results in bacterial attenuation and growth defectsin vitro. However, the roles of the two lipid A phosphate groups in bacterial virulence and immunogenicity remain unknown. Here, we used anS. TyphimuriummsbB pagL pagP lpxRmutant, carrying penta-acylated lipid A, as the parent strain to construct a series of mutants synthesizing 1-dephosphorylated, 4′-dephosphorylated, or nonphosphorylated penta-acylated lipid A. Dephosphorylated mutants exhibited increased sensitivity to deoxycholate and showed increased resistance to polymyxin B. Removal of both phosphate groups severely attenuated the mutants when administered orally to BALB/c mice, but the mutants colonized the lymphatic tissues and were sufficiently immunogenic to protect the host from challenge with wild-typeS. Typhimurium. Mice receivingS. Typhimurium with 1-dephosphorylated or nonphosphorylated penta-acylated lipid A exhibited reduced levels of cytokines. Attenuated and dephosphorylatedSalmonellavaccines were able to induce adaptive immunity against heterologous (PspA ofStreptococcus pneumoniae) and homologous antigens (lipopolysaccharide [LPS] and outer membrane proteins [OMPs]).

scholarly journals Demarcating SurA Activities Required for Outer Membrane Targeting of Yersinia pseudotuberculosis Adhesins

2013 ◽  
Vol 81 (7) ◽  
pp. 2296-2308 ◽  
Author(s):  
Ikenna R. Obi ◽  
Matthew S. Francis
Keyword(s):  
Outer Membrane ◽  
Yersinia Pseudotuberculosis ◽  
Biochemical Characterization ◽  
Outer Membrane Proteins ◽  
Genetic Mutation ◽  
Host Cells ◽  
Content Type ◽  
Chaperone Function ◽  
Bam Complex

ABSTRACTSurA is a periplasmic protein folding factor involved in chaperoning and trafficking of outer membrane proteins across the Gram-negative bacterial periplasm. In addition, SurA also possesses peptidyl-prolylcis/transisomerase activity. We have previously reported that in enteropathogenicYersinia pseudotuberculosis, SurA is needed for bacterial virulence and envelope integrity. In this study, we investigated the role of SurA in the assembly of importantYersiniaadhesins. Using genetic mutation, biochemical characterization, and anin vitro-based bacterial host cell association assay, we confirmed that surface localization of the invasin adhesin is dependent on SurA. As asurAdeletion also has some impact on the levels of individual components of the BAM complex in theYersiniaouter membrane, abolished invasin surface assembly could reflect both a direct loss of SurA-dependent periplasmic targeting and a potentially compromised BAM complex assembly platform in the outer membrane. To various degrees, the assembly of two other adhesins, Ail and the pH 6 antigen fibrillum PsaA, also depends on SurA. Consequently, loss of SurA leads to a dramatic reduction inYersiniaattachment to eukaryotic host cells. Genetic complementation ofsurAdeletion mutants indicated a prominent role for SurA chaperone function in outer membrane protein assembly. Significantly, the N terminus of SurA contributed most of this SurA chaperone function. Despite a dominant chaperoning role, it was also evident that SurA isomerization activity did make a modest contribution to this assembly process.

scholarly journals The KbvR Regulator Contributes to Capsule Production, Outer Membrane Protein Biosynthesis, Antiphagocytosis, and Virulence in Klebsiella pneumoniae

2021 ◽  
Vol 89 (5) ◽  
Author(s):  
Li Xu ◽  
Meng Wang ◽  
Jie Yuan ◽  
Hui Wang ◽  
Moran Li ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Outer Membrane ◽  
Capsular Polysaccharide ◽  
Protein Biosynthesis ◽  
Outer Membrane Proteins ◽  
Systemic Infection ◽  
Innate Immune ◽  
Content Type

ABSTRACT Klebsiella pneumoniae is an opportunistic pathogen that mostly affects patients with weakened immune systems, but a few serotypes (especially K1 and K2) are highly invasive and result in systemic infection in healthy persons. The ability to evade and survive the components of the innate immune system is critical in infection. To investigate the role and mechanism of transcription regulator KP1_RS12260 (KbvR) in virulence and defense against the innate immune response, kbvR deletion mutant and complement strains were constructed. The in vivo animal infection assay and in vitro antiphagocytosis assay demonstrate K. pneumoniae KbvR is an important regulator that contributes to virulence and the defense against phagocytosis of macrophages. The transcriptome analysis and phenotype experiments demonstrated that deletion of kbvR decreased production of capsular polysaccharide (CPS) and biosynthesis of partly outer membrane proteins (OMPs). The findings suggest that KbvR is a global regulator that confers pathoadaptive phenotypes, which provide several implications for improving our understanding of the pathogenesis of K. pneumoniae.

scholarly journals Immunoproteomic Analysis To Identify Shiga Toxin-Producing Escherichia coli Outer Membrane Proteins Expressed during Human Infection

2014 ◽  
Vol 82 (11) ◽  
pp. 4767-4777 ◽  
Author(s):  
David Montero ◽  
Paz Orellana ◽  
Daniela Gutiérrez ◽  
Daniela Araya ◽  
Juan Carlos Salazar ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Membrane Proteins ◽  
Outer Membrane ◽  
Shiga Toxin ◽  
Vaccine Development ◽  
Outer Membrane Proteins ◽  
Antibiotic Use ◽  
Etiologic Agent ◽  
Human Infection ◽  
Content Type

ABSTRACTShiga-toxin producingEscherichia coli(STEC) is the etiologic agent of acute diarrhea, dysentery, and hemolytic-uremic syndrome (HUS). There is no approved vaccine for STEC infection in humans, and antibiotic use is contraindicated, as it promotes Shiga toxin production. In order to identify STEC-associated antigens and immunogenic proteins, outer membrane proteins (OMPs) were extracted from STEC O26:H11, O103, O113:H21, and O157:H7 strains, and commensalE. colistrain HS was used as a control. SDS-PAGE, two-dimensional-PAGE analysis, Western blot assays using sera from pediatric HUS patients and controls, and matrix-assisted laser desorption ionization–tandem time of flight analyses were used to identify 12 immunogenic OMPs, some of which were not reactive with control sera. Importantly, seven of these proteins have not been previously reported to be immunogenic in STEC strains. Among these seven proteins, OmpT and Cah displayed IgG and IgA reactivity with sera from HUS patients. Genes encoding these two proteins were present in a majority of STEC strains. Knowledge of the antigens produced during infection of the host and the immune response to those antigens will be important for future vaccine development.

scholarly journals The Enolase of Borrelia burgdorferi Is a Plasminogen Receptor Released in Outer Membrane Vesicles

2011 ◽  
Vol 80 (1) ◽  
pp. 359-368 ◽  
Author(s):  
A. Toledo ◽  
J. L. Coleman ◽  
C. J. Kuhlow ◽  
J. T. Crowley ◽  
J. L. Benach
Keyword(s):  
Lyme Disease ◽  
Membrane Proteins ◽  
Borrelia Burgdorferi ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Proteinase K ◽  
Dependent Manner ◽  
Content Type

ABSTRACTThe agent of Lyme disease,Borrelia burgdorferi, has a number of outer membrane proteins that are differentially regulated during its life cycle. In addition to their physiological functions in the organism, these proteins also likely serve different functions in invasiveness and immune evasion. In borreliae, as well as in other bacteria, a number of membrane proteins have been implicated in binding plasminogen. The activation and transformation of plasminogen into its proteolytically active form, plasmin, enhances the ability of the bacteria to disseminate in the host. Outer membrane vesicles ofB. burgdorfericontain enolase, a glycolytic-cycle enzyme that catalyzes 2-phosphoglycerate to form phosphoenolpyruvate, which is also a known plasminogen receptor in Gram-positive bacteria. The enolase was cloned, expressed, purified, and used to generate rabbit antienolase serum. The enolase binds plasminogen in a lysine-dependent manner but not through ionic interactions. Although it is present in the outer membrane, microscopy and proteinase K treatment showed that enolase does not appear to be exposed on the surface. However, enolase in the outer membrane vesicles is accessible to proteolytic degradation by proteinase K. Samples from experimentally and tick-infected mice and rabbits as well as from Lyme disease patients exhibit recognition of enolase in serologic assays. Thus, this immunogenic plasminogen receptor released in outer membrane vesicles could be responsible for external proteolysis in the pericellular environment and have roles in nutrition and in enhancing dissemination.

scholarly journals Use of an Endogenous Plasmid Locus for Stable intransComplementation in Borrelia burgdorferi

2014 ◽  
Vol 81 (3) ◽  
pp. 1038-1046 ◽  
Author(s):  
Irene N. Kasumba ◽  
Aaron Bestor ◽  
Kit Tilly ◽  
Patricia A. Rosa
Keyword(s):  
Borrelia Burgdorferi ◽  
Shuttle Vector ◽  
Targeted Mutagenesis ◽  
Multiple Cloning Site ◽  
Stable Gene ◽  
Content Type ◽  
Shuttle Vectors ◽  
Stable Maintenance

ABSTRACTTargeted mutagenesis and complementation are important tools for studying genes of unknown function in the Lyme disease spirocheteBorrelia burgdorferi. A standard method of complementation is reintroduction of a wild-type copy of the targeted gene on a shuttle vector. However, shuttle vectors are present at higher copy numbers thanB. burgdorferiplasmids and are potentially unstable in the absence of selection, thereby complicating analyses in the mouse-tick infectious cycle.B. burgdorferihas over 20 plasmids, with some, such as linear plasmid 25 (lp25), carrying genes required by the spirochetein vivobut relatively unstable duringin vitrocultivation. We propose that complementation on an endogenous plasmid such as lp25 would overcome the copy number andin vivostability issues of shuttle vectors. In addition, insertion of a selectable marker on lp25 could ensure its stable maintenance by spirochetes in culture. Here, we describe the construction of a multipurpose allelic-exchange vector containing a multiple-cloning site and either of two selectable markers. This suicide vector directs insertion of the complementing gene into thebbe02locus, a site on lp25 that was previously shown to be nonessential during bothin vitroandin vivogrowth. We demonstrate the functional utility of this strategy by restoring infectivity to anospCmutant through complementation at this site on lp25 and stable maintenance of theospCgene throughout mouse infection. We conclude that this represents a convenient and widely applicable method for stable gene complementation inB. burgdorferi.

scholarly journals Mitochondrial Outer Membrane Proteins Assist Bid in Bax-mediated Lipidic Pore Formation

2009 ◽  
Vol 20 (8) ◽  
pp. 2276-2285 ◽  
Author(s):  
Blanca Schafer ◽  
Joel Quispe ◽  
Vineet Choudhary ◽  
Jerry E. Chipuk ◽  
Teddy G. Ajero ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Pore Formation ◽  
Outer Membrane Proteins ◽  
Mitochondrial Outer Membrane ◽  
Outer Membranes ◽  
Mitochondrial Outer Membrane Permeabilization ◽  
In Vitro Systems ◽  
Large Round ◽  
Key Features

Mitochondrial outer membrane permeabilization (MOMP) is a critical step in apoptosis and is regulated by Bcl-2 family proteins. In vitro systems using cardiolipin-containing liposomes have demonstrated the key features of MOMP induced by Bax and cleaved Bid; however, the nature of the “pores” and how they are formed remain obscure. We found that mitochondrial outer membranes contained very little cardiolipin, far less than that required for liposome permeabilization, despite their responsiveness to Bcl-2 family proteins. Strikingly, the incorporation of isolated mitochondrial outer membrane (MOM) proteins into liposomes lacking cardiolipin conferred responsiveness to cleaved Bid and Bax. Cardiolipin dependence was observed only when permeabilization was induced with cleaved Bid but not with Bid or Bim BH3 peptide or oligomerized Bax. Therefore, we conclude that MOM proteins specifically assist cleaved Bid in Bax-mediated permeabilization. Cryoelectron microscopy of cardiolipin-liposomes revealed that cleaved Bid and Bax produced large round holes with diameters of 25–100 nm, suggestive of lipidic pores. In sum, we propose that activated Bax induces lipidic pore formation and that MOM proteins assist cleaved Bid in this process in the absence of cardiolipin.

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