scholarly journals Ferrous iron-binding protein Omb of Salmonella enterica serovar Choleraesuis promotes resistance to hydrophobic antibiotics and contributes to its virulence

Microbiology ◽  
2009 ◽  
Vol 155 (7) ◽  
pp. 2365-2374 ◽  
Author(s):  
Jer-Horng Su ◽  
Yin-Ching Chung ◽  
Hsin-Chun Lee ◽  
I-Cheng Tseng ◽  
Ming-Chung Chang
Keyword(s):  
Outer Membrane ◽  
Salmonella Enterica ◽  
Ferrous Iron ◽  
Binding Protein ◽  
Polymyxin B ◽  
Iron Binding ◽  
Virulence Attenuation ◽  
Increased Sensitivity ◽  
Iron Binding Protein

Salmonella enterica serovar Choleraesuis (SC) is an important enteric pathogen that causes serious systemic infections in swine and humans. To identify the genes required for resistance to antimicrobial peptides, we constructed a bank of SC transposon mutants and screened them for hypersensitivity to the cationic peptide polymyxin B. Here we report one isolated polymyxin B-susceptible mutant that also exhibited increased sensitivity toward human neutrophil peptide alpha-defensin 1 (HNP-1) and hydrophobic antibiotics including erythromycin and novobiocin. The mutant had a mutation in an ORF identified as outer membrane β-barrel protein gene omb. The purified recombinant Omb protein was characterized as a ferrous iron-binding protein. The constructed omb isogenic mutant grew more slowly in iron-limiting conditions than the wild-type (WT) parent strain. In addition, compared with the WT strain, the omb mutant exhibited an increase in net negative charge upon the cell surface and was more easily killed by polymyxin B, HNP-1 and hydrophobic antibiotics. The omb gene was transcribed, regardless of the iron content within the growth medium, and the Omb protein appeared exclusively in the outer membrane fraction. Infection experiments demonstrated virulence attenuation when the mutant was administered orally or intraperitoneally to mice. This study indicates that Omb is a previously unrecognized ferrous iron-binding protein. In vivo, Omb may be involved in the acquisition of ferrous iron during the initial stages of SC infection and appears to be an important virulence factor for SC in mice.

scholarly journals Acquisition of Mn(II) in Addition to Fe(II) Is Required for Full Virulence of Salmonella enterica Serovar Typhimurium

2002 ◽  
Vol 70 (11) ◽  
pp. 6032-6042 ◽  
Author(s):  
E. Boyer ◽  
I. Bergevin ◽  
D. Malo ◽  
P. Gros ◽  
M. F. M. Cellier
Keyword(s):  
Salmonella Enterica ◽  
Ferrous Iron ◽  
Double Mutant ◽  
Divalent Cations ◽  
Intracellular Survival ◽  
Iron Transporter ◽  
Serovar Typhimurium ◽  
Increased Sensitivity

ABSTRACT The roles of the genes feoB (ABC ferrous iron transporter), mntH (proton-dependent manganese transporter), and sitABCD (putative ABC iron and/or manganese transporter) in Salmonella pathogenicity were investigated by using mutant strains deficient in one, two, or three transporters. Our results indicated that sitABCD encodes an important transporter of Mn(II) and Fe(II) which is required for full virulence in susceptible animals (Nramp1 −/−) and for replication inside Nramp1 −/− macrophages in vitro. The mntH sitABCD double mutant (mutant MS) showed minimal Mn(II) uptake and increased sensitivity to H2O2 and to the divalent metal chelator 2,2′-dipyridyl (DP) and was defective for replication in macrophages. In vivo MS appeared to be as virulent as the sitABCD mutant in Nramp1 −/− animals. The ferrous iron transporter Feo was required for full virulence in 129/Sv Nramp1 −/− mice, and infection with multiple mutants lacking FeoB was not fatal. The sitABCD feoB mutant (mutant SF) and the mntH sitABCD feoB mutant (mutant MSF) showed minimal Fe(II) uptake and were slightly impaired for replication in susceptible macrophages. MSF showed reduced growth in minimal medium deficient in divalent cations. The role of the mntH gene, which is homologous to mammalian Nramp genes, was also investigated after overexpression in the double mutant MS. MntH preferred Mn(II) over Fe(II) and could suppress MS sensitivity to H2O2 and to DP, and it also improved the intracellular survival in Nramp1 −/− macrophages. This study indicates that acquisition of Mn(II), in addition to Fe(II), is required for intracellular survival and replication of Salmonella enterica serovar Typhimurium in macrophages in vitro and for virulence in vivo.

scholarly journals Identification of lactoferrin as the granulocyte-derived inhibitor of colony-stimulating activity production.

1978 ◽  
Vol 148 (4) ◽  
pp. 1052-1067 ◽  
Author(s):  
H E Broxmeyer ◽  
A Smithyman ◽  
R R Eger ◽  
P A Meyers ◽  
M de Sousa
Keyword(s):  
Binding Protein ◽  
Iron Binding ◽  
Blood Monocytes ◽  
Iron Saturation ◽  
Colony Stimulating Activity ◽  
Monocytes And Macrophages ◽  
Iron Binding Protein ◽  
Macrophage Colony

Lactoferrin (LF), the iron-binding protein present in the specific granules of mature granulocytes has been identified as colony inhibitory factor (CIF) which suppresses granulocyte--macrophage colony stimulating activity (CSA) production by monocytes and macrophages in vitro and rebound granulopoiesis in vivo. Separation of LF and CIF by isoelectric focusing confirmed that the regions of inhibitory activity corresponded in both to a pH of congruent to 6.5. In addition, the purified immunoglobulin fraction of rabbit anti-human LF antiserum, but not rabbit anti-transferrin (TF), inactivated the capacity of LF and CIF to inhibit CSA production, an effect blocked by prior incubation of anti-LF with neutralizing concentrations of LF. Suppression of CSA production correlated with the iron-saturation of LF; APO-LF (depleted of iron) was only active concentrations greater than 10(-7) M, native LF (8% iron saturated) was active at 10(-15) M, and fully iron-saturated LF inhibited at 10(-17) M. Suppression of CSA production occurred within a 1/2-h preincubation period with human blood monocytes but was reversed by bacterial lipopolysaccharide (LPS). This reversal was dependent on the relative concentrations of LF to LPS. Serum TF, a biochemically similar iron-binding protein which is antigenically distinct from LF, was only minimally active at concentrations greater than 10(-6) M. LF did not inhibit exogenously stimulated human granylocyte and macrophage colony-forming cells or erythropoietin-dependent human or murine erythroid colony- or erythroid burst-forming cells. Microgram quantities of LF acted in vivo to inhibit rebound granulopoiesis and CSA production in CD1 and C57Bl/6 mice pretreated with cyclophosphamide. These results strongly implicate LF as a physiological regulator of granulopoiesis.

scholarly journals Protecting against Antimicrobial Effectors in the Phagosome Allows SodCII To Contribute to Virulence in Salmonella enterica Serovar Typhimurium

2010 ◽  
Vol 192 (8) ◽  
pp. 2140-2149 ◽  
Author(s):  
Byoungkwan Kim ◽  
Susan M. Richards ◽  
John S. Gunn ◽  
James M. Slauch
Keyword(s):  
Antimicrobial Peptides ◽  
Antimicrobial Peptide ◽  
Outer Membrane ◽  
Salmonella Enterica ◽  
Osmotic Shock ◽  
Polymyxin B ◽  
Antimicrobial Substances ◽  
Serovar Typhimurium

ABSTRACT Salmonella enterica serovar Typhimurium replicates in macrophages, where it is subjected to antimicrobial substances, including superoxide, antimicrobial peptides, and proteases. The bacterium produces two periplasmic superoxide dismutases, SodCI and SodCII. Although both are expressed during infection, only SodCI contributes to virulence in the mouse by combating phagocytic superoxide. The differential contribution to virulence is at least partially due to inherent differences in the SodCI and SodCII proteins that are independent of enzymatic activity. SodCII is protease sensitive, and like other periplasmic proteins, it is released by osmotic shock. In contrast, SodCI is protease resistant and is retained within the periplasm after osmotic shock, a phenomenon that we term “tethering.” We hypothesize that in the macrophage, antimicrobial peptides transiently disrupt the outer membrane. SodCII is released and/or phagocytic proteases gain access to the periplasm, and SodCII is degraded. SodCI is tethered within the periplasm and is protease resistant, thereby remaining to combat superoxide. Here we test aspects of this model. SodCII was released by the antimicrobial peptide polymyxin B or a mouse macrophage antimicrobial peptide (CRAMP), while SodCI remained tethered within the periplasm. A Salmonella pmrA constitutive mutant no longer released SodCII in vitro. Moreover, in the constitutive pmrA background, SodCII could contribute to survival of Salmonella during infection. SodCII also provided a virulence benefit in mice genetically defective in production of CRAMP. Thus, consistent with our model, protecting the outer membrane against antimicrobial peptides allows SodCII to contribute to virulence in vivo. These data also suggest direct in vivo cooperative interactions between macrophage antimicrobial effectors.

The iron-binding protein ferritin is expressed in cells of the osteoblastic lineage in vitro and in vivo

Bone ◽  
1995 ◽  
Vol 17 (2) ◽  
pp. 161-165 ◽  
Author(s):  
M. Spanner ◽  
K. Weber ◽  
B. Lanske ◽  
A. Ihbe ◽  
H. Siggelkow ◽  
...  
Keyword(s):  
Binding Protein ◽  
Iron Binding ◽  
Osteoblastic Lineage ◽  
Iron Binding Protein ◽  
In Cells

scholarly journals Lactoferrin-an iron binding protein in synovial fluid

1973 ◽  
Vol 16 (2) ◽  
pp. 186-190 ◽  
Author(s):  
Robert M Bennett ◽  
A C Eddie-Quartey ◽  
P J L Holt
Keyword(s):  
Synovial Fluid ◽  
Binding Protein ◽  
Iron Binding ◽  
Iron Binding Protein

scholarly journals Iron-Binding Protein of Swine Serum.

1947 ◽  
Vol 1 ◽  
pp. 770-776 ◽  
Author(s):  
C.-B Laurell ◽  
B. Ingelman
Keyword(s):  
Binding Protein ◽  
Iron Binding ◽  
Iron Binding Protein ◽  
Swine Serum

scholarly journals Role of sapA and yfgA in Susceptibility to Antibody-Mediated Complement-Dependent Killing and Virulence of Salmonella enterica Serovar Typhimurium

2017 ◽  
Vol 85 (9) ◽  
Author(s):  
Edna M. Ondari ◽  
Jennifer N. Heath ◽  
Elizabeth J. Klemm ◽  
Gemma Langridge ◽  
Lars Barquist ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Protein Translocation ◽  
Invasive Disease ◽  
Immune Serum ◽  
Insertion Mutant ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Serum Killing ◽  
Increased Sensitivity

ABSTRACT The ST313 pathovar of Salmonella enterica serovar Typhimurium contributes to a high burden of invasive disease among African infants and HIV-infected adults. It is characterized by genome degradation (loss of coding capacity) and has increased resistance to antibody-dependent complement-mediated killing compared with enterocolitis-causing strains of S. Typhimurium. Vaccination is an attractive disease-prevention strategy, and leading candidates focus on the induction of bactericidal antibodies. Antibody-resistant strains arising through further gene deletion could compromise such a strategy. Exposing a saturating transposon insertion mutant library of S. Typhimurium to immune serum identified a repertoire of S. Typhimurium genes that, when interrupted, result in increased resistance to serum killing. These genes included several involved in bacterial envelope biogenesis, protein translocation, and metabolism. We generated defined mutant derivatives using S. Typhimurium SL1344 as the host. Based on their initial levels of enhanced resistance to killing, yfgA and sapA mutants were selected for further characterization. The S. Typhimurium yfgA mutant lost the characteristic Salmonella rod-shaped appearance, exhibited increased sensitivity to osmotic and detergent stress, lacked very long lipopolysaccharide, was unable to invade enterocytes, and demonstrated decreased ability to infect mice. In contrast, the S. Typhimurium sapA mutants had similar sensitivity to osmotic and detergent stress and lipopolysaccharide profile and an increased ability to infect enterocytes compared with the wild type, but it had no increased ability to cause in vivo infection. These findings indicate that increased resistance to antibody-dependent complement-mediated killing secondary to genetic deletion is not necessarily accompanied by increased virulence and suggest the presence of different mechanisms of antibody resistance.

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