scholarly journals Interactions of Bacterial Cationic Peptide Antibiotics with Outer and Cytoplasmic Membranes ofPseudomonas aeruginosa

2000 ◽  
Vol 44 (12) ◽  
pp. 3317-3321 ◽  
Author(s):  
Lijuan Zhang ◽  
Pawandeep Dhillon ◽  
Hong Yan ◽  
Susan Farmer ◽  
Robert E. W. Hancock
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Cell ◽  
Cytoplasmic Membrane ◽  
Peptide Antibiotics ◽  
Cationic Peptide ◽  
Wild Type ◽  
Gramicidin S ◽  
Cytoplasmic Membranes ◽  
Cell Lethality ◽  
Pao1 Strain

ABSTRACT Polymyxins B and E1 and gramicidin S are bacterium-derived cationic antimicrobial peptides. The polymyxins were more potent than gramicidin S against Pseudomonas aeruginosa, with MICs of 0.125 to 0.25 and 8 μg/ml, respectively. These peptides differed in their affinities for binding to lipopolysaccharide, but all were able to permeabilize the outer membrane of wild-type P. aeruginosaPAO1 strain H103, suggesting differences in their mechanisms of self-promoted uptake. Gramicidin S caused rapid depolarization of the bacterial cytoplasmic membrane at concentrations at which no killing was observed within 30 min, whereas, conversely, the concentrations of the polymyxins that resulted in rapid killing resulted in minimal depolarization. These data indicate that the depolarization of the cytoplasmic membrane by these peptides did not correlate with bacterial cell lethality.

scholarly journals Polyamines Induce Resistance to Cationic Peptide, Aminoglycoside, and Quinolone Antibiotics in Pseudomonas aeruginosa PAO1

2006 ◽  
Vol 50 (5) ◽  
pp. 1615-1622 ◽  
Author(s):  
Dong H. Kwon ◽  
Chung-Dar Lu
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Fluorescent Dyes ◽  
Polymyxin B ◽  
Polyamine Metabolism ◽  
Peptide Antibiotic ◽  
Peptide Antibiotics ◽  
Cationic Peptide ◽  
Human Pathogens ◽  
Adaptive Responses ◽  
Multiple Antibiotics

ABSTRACT Pseudomonas aeruginosa, a gram-negative bacterium of human pathogens, is noted for its environmental versatility, enormous metabolic capacity, and resistance to antibiotics. Overexpression of the outer membrane protein OprH and increased resistance to polycationic peptide antibiotics (e.g., polymyxin B) mediated by the PhoPQ two-component system on induction of a putative lipopolysaccharide (LPS) modification operon (PA3552-PA3559) have been reported as part of the adaptive responses to magnesium limitation in P. aeruginosa. Induction of the oprH-phoPQ operon and the LPS modification operon by exogenous spermidine was revealed from GeneChip analysis during studies of polyamine metabolism and was confirmed by the lacZ fusions of affected promoters. From the results of MIC measurements, it was found that addition of spermidine or other polyamines to the growth medium increased the MIC values of multiple antibiotics, including polycationic antibiotics, aminoglycosides, quinolones, and fluorescent dyes. MIC values of these compounds in the transposon insertion mutants of oprH, phoP, phoQ, and pmrB were also determined in the presence and absence of spermidine. The results showed that the spermidine effect on cationic peptide antibiotic and quinolone resistance was diminished in the phoP mutant only. The spermidine effect on antibiotics was not influenced by magnesium concentrations, as demonstrated by MICs and oprH::lacZ fusion studies in the presence of 20 μM or 2 mM magnesium. Furthermore, in spermidine uptake mutants, MICs of cationic peptide antibiotics and fluorescent dyes, but not of aminoglycosides and quinolones, were increased by spermidine. These results suggested the presence of a complicated molecular mechanism for polyamine-mediated resistance to multiple antibiotics in P. aeruginosa.

scholarly journals Role of TonB1 in Pyoverdine-Mediated Signaling in Pseudomonas aeruginosa

2009 ◽  
Vol 191 (18) ◽  
pp. 5634-5640 ◽  
Author(s):  
Matt Shirley ◽  
Iain L. Lamont
Keyword(s):  
Gene Expression ◽  
Pseudomonas Aeruginosa ◽  
Sigma Factor ◽  
Phenylacetic Acid ◽  
Cytoplasmic Membrane ◽  
Receptor Protein ◽  
Wild Type ◽  
Membrane Spanning ◽  
Signaling Process

ABSTRACT Pyoverdines are siderophores secreted by Pseudomonas aeruginosa. Uptake of ferripyoverdine in P. aeruginosa PAO1 occurs via the FpvA receptor protein and requires the energy-transducing protein TonB1. Interaction of (ferri)pyoverdine with FpvA activates pyoverdine gene expression in a signaling process involving the cytoplasmic-membrane-spanning anti-sigma factor FpvR and the sigma factor PvdS. Here, we show that mutation of a region of FpvA that interacts with TonB1 (the TonB box) prevents this signaling process, as well as inhibiting bacterial growth in the presence of the iron-chelating compound ethylenediamine-di(o-hydroxy-phenylacetic acid). Signaling via wild-type FpvA was also eliminated in strains lacking TonB1 but was unaffected in strains lacking either (or both) of two other TonB proteins in P. aeruginosa, TonB2 and TonB3. An absence of pyoverdine-mediated signaling corresponded with proteolysis of PvdS. These data show that interactions between FpvA and TonB1 are required for (ferri)pyoverdine signal transduction, as well as for ferripyoverdine transport, consistent with a mechanistic link between the signaling and transport functions of FpvA.

scholarly journals Role of Pseudomonas aeruginosa Low-Molecular-Mass Penicillin-Binding Proteins in AmpC Expression, β-Lactam Resistance, and Peptidoglycan Structure

2015 ◽  
Vol 59 (7) ◽  
pp. 3925-3934 ◽  
Author(s):  
Alaa Ropy ◽  
Gabriel Cabot ◽  
Irina Sánchez-Diener ◽  
Cristian Aguilera ◽  
Bartolome Moya ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Molecular Mass ◽  
Binding Proteins ◽  
Wild Type ◽  
Content Type ◽  
Penicillin Binding Proteins ◽  
Peptidoglycan Structure ◽  
The Impact ◽  
Pao1 Strain

ABSTRACTThis study aimed to characterize the role ofPseudomonas aeruginosalow-molecular-mass penicillin-binding proteins (LMM PBPs), namely, PBP4 (DacB), PBP5 (DacC), and PBP7 (PbpG), in peptidoglycan composition, β-lactam resistance, andampCregulation. For this purpose, we constructed all single and multiple mutants ofdacB,dacC,pbpG, andampCfrom the wild-typeP. aeruginosaPAO1 strain. Peptidoglycan composition was determined by high-performance liquid chromatography (HPLC),ampCexpression by reverse transcription-PCR (RT-PCR), PBP patterns by a Bocillin FL-binding test, and antimicrobial susceptibility by MIC testing for a panel of β-lactams. Microscopy and growth rate analyses revealed no apparent major morphological changes for any of the mutants compared to the wild-type PAO1 strain. Of the single mutants, onlydacCmutation led to significantly increased pentapeptide levels, showing that PBP5 is the majordd-carboxypeptidase inP. aeruginosa. Moreover, our results indicate that PBP4 and PBP7 play a significant role asdd-carboxypeptidase only if PBP5 is absent, and theirdd-endopeptidase activity is also inferred. As expected, the inactivation of PBP4 led to a significant increase inampCexpression (around 50-fold), but, remarkably, the sequential inactivation of the three LMM PBPs produced a much greater increase (1,000-fold), which correlated with peptidoglycan pentapeptide levels. Finally, the β-lactam susceptibility profiles of the LMM PBP mutants correlated well with theampCexpression data. However, the inactivation ofampCin these mutants also evidenced a role of LMM PBPs, especially PBP5, in intrinsic β-lactam resistance. In summary, in addition to assessing the effect ofP. aeruginosaLMM PBPs on peptidoglycan structure for the first time, we obtained results that represent a step forward in understanding the impact of these PBPs on β-lactam resistance, apparently driven by the interplay between their roles in AmpC induction, β-lactam trapping, anddd-carboxypeptidase/β-lactamase activity.

scholarly journals Assembly of XcpR in the Cytoplasmic Membrane Is Required for Extracellular Protein Secretion in Pseudomonas aeruginosa

1999 ◽  
Vol 181 (2) ◽  
pp. 382-388 ◽  
Author(s):  
Geneviève Ball ◽  
Virginie Chapon-Hervé ◽  
Sophie Bleves ◽  
Gérard Michel ◽  
Marc Bally
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Secretory Pathway ◽  
Cytoplasmic Membrane ◽  
Extracellular Proteins ◽  
Membrane Association ◽  
Stoichiometric Ratio ◽  
Gene Products ◽  
Type Ii ◽  
Wild Type ◽  
The Relationship

ABSTRACT A broad range of extracellular proteins secreted byPseudomonas aeruginosa use the type II or general secretory pathway (GSP) to reach the medium. This pathway requires the expression of at least 12 xcp gene products. XcpR, a putative nucleotide-binding protein, is essential for the secretion process across the outer membrane even though the protein contains no hydrophobic sequence that could target or anchor it to the bacterial envelope. For a better understanding of the relationship between XcpR and the other Xcp proteins which are located in the envelope, we have studied its subcellular localization. In a wild-type P. aeruginosa strain, XcpR was found associated with the cytoplasmic membrane. This association depends on the presence of the XcpY protein, which also appears to be necessary for XcpR stability. Functional complementation of an xcpY mutant required the XcpY protein to be expressed at a low level. Higher expression precluded the complementing activity of XcpY, although membrane association of XcpR was restored. This behavior suggested that an excess of free XcpY might interfere with the secretion by formation of inactive XcpR-XcpY complexes which cannot properly interact with their natural partners in the secretion machinery. These data show that a precise stoichiometric ratio between several components may be crucial for the functioning of the GSP.

scholarly journals Characterization of the arcD arginine:ornithine exchanger of Pseudomonas aeruginosa. Localization in the cytoplasmic membrane and a topological model.

1993 ◽  
Vol 268 (8) ◽  
pp. 5417-5424
Author(s):  
J.P. Bourdineaud ◽  
D. Heierli ◽  
M. Gamper ◽  
H.J. Verhoogt ◽  
A.J. Driessen ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cytoplasmic Membrane ◽  
Topological Model

scholarly journals Biofilm formation by Pseudomonas aeruginosa wild type, flagella and type IV pili mutants

2003 ◽  
Vol 48 (6) ◽  
pp. 1511-1524 ◽  
Author(s):  
Mikkel Klausen ◽  
Arne Heydorn ◽  
Paula Ragas ◽  
Lotte Lambertsen ◽  
Anders Aaes-Jørgensen ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Type Iv Pili ◽  
Wild Type ◽  
Type Iv

scholarly journals ParB deficiency in Pseudomonas aeruginosa destabilizes the partner protein ParA and affects a variety of physiological parameters

Microbiology ◽  
2009 ◽  
Vol 155 (4) ◽  
pp. 1080-1092 ◽  
Author(s):  
A. A. Bartosik ◽  
J. Mierzejewska ◽  
C. M. Thomas ◽  
G. Jagura-Burdzy
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Fluorescence Microscopy ◽  
Bacterial Growth ◽  
Complete Loss ◽  
Physiological Parameters ◽  
Wild Type ◽  
Partial Removal ◽  
Partner Protein ◽  
The One ◽  
Mutant Phenotypes

Deletions leading to complete or partial removal of ParB were introduced into the Pseudomonas aeruginosa chromosome. Fluorescence microscopy of fixed cells showed that ParB mutants lacking the C-terminal domain or HTH motif formed multiple, less intense foci scattered irregularly, in contrast to the one to four ParB foci per cell symmetrically distributed in wild-type P. aeruginosa. All parB mutations affected both bacterial growth and swarming and swimming motilities, and increased the production of anucleate cells. Similar effects were observed after inactivation of parA of P. aeruginosa. As complete loss of ParA destabilized its partner ParB it was unclear deficiency of which protein is responsible for the mutant phenotypes. Analysis of four parB mutants showed that complete loss of ParB destabilized ParA whereas three mutants that retained the N-terminal 90 aa of ParB did not. As all four parB mutants demonstrate the same defects it can be concluded that either ParB, or ParA and ParB in combination, plays an important role in nucleoid distribution, growth and motility in P. aeruginosa.

Antibacterial effect of hyaluronan/chitosan nanofilm in the initial adhesion of Pseudomonas aeruginosa wild type, and IV pili and LPS mutant strains

2021 ◽  
pp. 101415
Author(s):  
Jacobo Hernandez-Montelongo ◽  
Gianlucca G. Nicastro ◽  
Thays de O. Pereira ◽  
Mariana Zavarize ◽  
Marisa M. Beppu ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibacterial Effect ◽  
Wild Type ◽  
Initial Adhesion ◽  
Mutant Strains

scholarly journals Nutritional Effects on Host Response to Lung Infections with Mucoid Pseudomonas aeruginosa in Mice

2004 ◽  
Vol 72 (3) ◽  
pp. 1479-1486 ◽  
Author(s):  
Anna M. van Heeckeren ◽  
Mark Schluchter ◽  
Lintong Xue ◽  
Juan Alvarez ◽  
Steven Freedman ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Docosahexaenoic Acid ◽  
Knockout Mice ◽  
Host Response ◽  
Inflammatory Responses ◽  
Liquid Diet ◽  
Wild Type ◽  
Agarose Beads ◽  
Lung Infections

ABSTRACT In cystic fibrosis, a recessive genetic disease caused by defects in the cystic fibrosis conductance regulator (CFTR), the main cause of death is lung infection and inflammation. Nutritional deficits have been proposed to contribute to the excessive host inflammatory response in both humans and Cftr-knockout mice. Cftr-knockout mice and gut-corrected Cftr-knockout mice expressing human CFTR primarily in the gut were challenged with Pseudomonas aeruginosa-laden agarose beads; they responded similarly with respect to bronchoalveolar lavage cell counts and levels of the acute-phase cytokines tumor necrosis factor alpha, interleukin-1β (IL-1β), and IL-6. Wild-type mice fed the liquid diet used to prevent intestinal obstruction in Cftr-knockout mice had inflammatory responses to P. aeruginosa-laden agarose beads similar to those of wild-type mice fed an enriched solid diet, so dietary effects are unlikely to account for differences between wild-type mice and mice with cystic fibrosis. Finally, since cystic fibrosis patients and Cftr-knockout mice have an imbalance in fatty acids (significantly lower-than-normal levels of docosahexaenoic acid), the effects of specific supplementation with docosahexaenoic acid of wild-type and Cftr-knockout mice on their inflammatory responses to P. aeruginosa-laden agarose beads were tested. There were no significant differences (P = 0.35) in cumulative survival rates between Cftr-knockout mice and wild-type mice provided with either the liquid diet Peptamen or Peptamen containing docosahexaenoic acid. In conclusion, diet and docosahexaenoic acid imbalances alone are unlikely to explain the differences in the host response to lung infections with mucoid P. aeruginosa between mice with cystic fibrosis and their wild-type counterparts.

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