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 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 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 Identification of a Siderophore Receptor Required for Ferric Ornibactin Uptake in Burkholderia cepacia

2000 ◽  
Vol 68 (12) ◽  
pp. 6554-6560 ◽  
Author(s):  
P. A. Sokol ◽  
P. Darling ◽  
S. Lewenza ◽  
C. R. Corbett ◽  
C. D. Kooi
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Burkholderia Cepacia ◽  
Parent Strain ◽  
Respiratory Infections ◽  
Infection Model ◽  
Protein Profiles ◽  
Outer Membrane Receptor ◽  
Gene Encoding

ABSTRACT Ornibactins are linear hydroxamate siderophores produced byBurkholderia cepacia with peptide structures similar to that of pyoverdines produced by the fluorescent pseudomonads. The gene encoding the outer membrane receptor (orbA) was identified, sequenced, and demonstrated to have significant homology with hydroxamate receptors produced by other organisms. The orbAprecursor was predicted to be a protein with a molecular mass of 81 kDa. An orbA mutant was constructed and demonstrated to be unable to take up 59Fe-ornibactins or to grow in medium supplemented with ornibactins. Outer membrane protein profiles from the parent strain, K56-2, revealed an iron-regulated outer membrane protein of 78 kDa that was not detectable in the K56orbA::tp mutant. When this mutant harbored a plasmid containing the orbA gene, the 78-kDa protein was present in the outer membrane protein profiles and the mutant was able to utilize ornibactin to acquire iron. The orbA mutant was less virulent in a chronic respiratory infection model than the parent strain, indicating that ornibactin uptake and utilization are important in the pathogenesis of B. cepacia respiratory infections.

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 Production of Chlamydia pneumoniae Proteins in Bacillus subtilis and Their Use in Characterizing Immune Responses in the Experimental Infection Model

2003 ◽  
Vol 10 (3) ◽  
pp. 367-375 ◽  
Author(s):  
Ulla Airaksinen ◽  
Tuula Penttilä ◽  
Eva Wahlström ◽  
Jenni M. Vuola ◽  
Mirja Puolakkainen ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Large Scale ◽  
Chlamydia Pneumoniae ◽  
Signal Sequence ◽  
Expression Vectors ◽  
Infection Model

ABSTRACT Due to intracellular growth requirements, large-scale cultures of chlamydiae and purification of its proteins are difficult and laborious. To overcome these problems we produced chlamydial proteins in a heterologous host, Bacillus subtilis, a gram-positive nonpathogenic bacterium. The genes of Chlamydia pneumoniae major outer membrane protein (MOMP), the cysteine-rich outer membrane protein (Omp2), and the heat shock protein (Hsp60) were amplified by PCR, and the PCR products were cloned into expression vectors containing a promoter, a ribosome binding site, and a truncated signal sequence of the α-amylase gene from Bacillus amyloliquefaciens. C. pneumoniae genes were readily expressed in B. subtilis under the control of the α-amylase promoter. The recombinant proteins MOMP and Hsp60 were purified from the bacterial lysate with the aid of the carboxy-terminal histidine hexamer tag by affinity chromatography. The Omp2 was separated as an insoluble fraction after 8 M urea treatment. The purified proteins were successfully used as immunogens and as antigens in serological assays and in a lymphoproliferation test. The Omp2 and Hsp60 antigens were readily recognized by the antibodies appearing after pulmonary infection following intranasal inoculation of C. pneumoniae in mice. Also, splenocytes collected from mice immunized with MOMP or Hsp60 proteins proliferated in response to in vitro stimulation with the corresponding proteins.

scholarly journals JASSY, a chloroplast outer membrane protein required for jasmonate biosynthesis

2019 ◽  
Vol 116 (21) ◽  
pp. 10568-10575 ◽  
Author(s):  
Li Guan ◽  
Niels Denkert ◽  
Ahmed Eisa ◽  
Martin Lehmann ◽  
Inga Sjuts ◽  
...  
Keyword(s):  
Stress Response ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Cold Acclimation ◽  
Outer Membrane Protein ◽  
Plant Hormones ◽  
Target Genes ◽  
Chloroplast Membranes ◽  
Pathogen Attack ◽  
Abiotic Influences

Jasmonates are vital plant hormones that not only act in the stress response to biotic and abiotic influences, such as wounding, pathogen attack, and cold acclimation, but also drive developmental processes in cooperation with other plant hormones. The biogenesis of jasmonates starts in the chloroplast, where several enzymatic steps produce the jasmonate precursor 12-oxophytodienoic acid (OPDA) from α-linolenic acid. OPDA in turn is exported into the cytosol for further conversion into active jasmonates, which subsequently induces the expression of multiple genes in the nucleus. Despite its obvious importance, the export of OPDA across the chloroplast membranes has remained elusive. In this study, we characterized a protein residing in the chloroplast outer membrane, JASSY, which has proven indispensable for the export of OPDA from the chloroplast. We provide evidence that JASSY has channel-like properties and propose that it thereby facilitates OPDA transport. Consequently, a lack of JASSY in Arabidopsis leads to a deficiency in accumulation of jasmonic acids, which results in impaired expression of jasmonate target genes on exposure to various stresses. This results in plants that are more susceptible to pathogen attack and also exhibit defects in cold acclimation.

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