Characterization of a protein-lipopolysaccharide complex released from cell walls of <i>Pseudomonas aeruginosa</i> by ethylenediaminetetraacetic acid

Rogers, S. W.; Gilleland, H. E.; Eagon, R. G.

doi:10.1139/m69-130

Cited by 98 publications

(69 citation statements)

References 4 publications

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“…This action of EDTA is attributed to the chelation of divalent metals which are required for the structural integrity of the cell envelope (1, 7). Rogers et al (21) demonstrated that a proteinlipopolysaccharide complex is released from the cell envelope by EDTA. Repaske (19) found that EDTA allows lysozyme to attack cell walls of certain bacteria.…”

Section: Discussionmentioning

confidence: 99%

Penicillin-Resistant Mechanisms in Pseudomonas aeruginosa : Binding of Penicillin to Pseudomonas aeruginosa KM 338

Suginaka

Ichikawa

Kotani

1975

Antimicrob Agents Chemother

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A comparison of the binding of radioactive penicillin G to whole cells and the membrane fraction derived from Pseudomonas aeruginosa KM 338 was made. This organism has intrinsic resistance to penicillin. The binding to the membrane fraction which catalyzed peptidoglycan synthesis followed saturation type kinetics and saturation was achieved at approximately 2 nmol of penicillin G per ml, whereas binding to the whole cells was entirely of the nonsaturation type. The binding of carbenicillin to the membrane fraction was determined by competition between radioactive penicillin G and unlabeled carbenicillin for the binding sites. It was bound at the same sites in almost the same manner. When whole cells were pretreated with high concentration of unlabeled penicillin G or carbenicillin, the subsequent binding of radioactive penicillin G to the membrane fraction from carbenicillin-treated cells was entirely nonspecific, but with penicillin G-pretreated cells it was still specific. There was apparently specific binding of radioactive penicillin G to ethylenediaminetetraacetate-treated cells. P. aeruginosa KM 338 had an extremely low activity of β-lactamase compared with other enzyme-producing organisms. This enzyme from P. aeruginosa KM 338 was of the cephalosporinase type. These data indicate that penicillin resistance of P. aeruginosa KM 338 may be a consequence of the development of a permeability barrier which prevents the antibiotic from reaching its sites of action in the cytoplasmic membrane.

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Section: Discussionmentioning

confidence: 99%

Penicillin-Resistant Mechanisms in Pseudomonas aeruginosa : Binding of Penicillin to Pseudomonas aeruginosa KM 338

Suginaka

Ichikawa

Kotani

1975

Antimicrob Agents Chemother

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“…For example, LPS mutants which have lost the O antigen component have increased affinity for hydrophobic probes (14,23,25,29,31,32). EDTA treatment of cells has been shown to cause partial release of LPS (4,5,15,30), resulting in cells that are more susceptible to the action of hydrophobic antibiotics (15, 16). The mechanism of EDTA-induced LPS loss is through chelation of divalent cations, namely Mg 2ϩ , which results in a weakening of LPS-LPS interaction and release of LPS to the growth medium (25).…”

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confidence: 99%

Rhamnolipid-Induced Removal of Lipopolysaccharide from Pseudomonas aeruginosa : Effect on Cell Surface Properties and Interaction with Hydrophobic Substrates

Al-Tahhan

Sandrin

Bodour

et al. 2000

Appl Environ Microbiol

390

236

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Little is known about the interaction of biosurfactants with bacterial cells. Recent work in the area of biodegradation suggests that there are two mechanisms by which biosurfactants enhance the biodegradation of slightly soluble organic compounds. First, biosurfactants can solubilize hydrophobic compounds within micelle structures, effectively increasing the apparent aqueous solubility of the organic compound and its availability for uptake by a cell. Second, biosurfactants can cause the cell surface to become more hydrophobic, thereby increasing the association of the cell with the slightly soluble substrate. Since the second mechanism requires very low levels of added biosurfactant, it is the more intriguing of the two mechanisms from the perspective of enhancing the biodegradation process. This is because, in practical terms, addition of low levels of biosurfactants will be more cost-effective for bioremediation. To successfully optimize the use of biosurfactants in the bioremediation process, their effect on cell surfaces must be understood. We report here that rhamnolipid biosurfactant causes the cell surface of Pseudomonas spp. to become hydrophobic through release of lipopolysaccharide (LPS). In this study, two Pseudomonas aeruginosa strains were grown on glucose and hexadecane to investigate the chemical and structural changes that occur in the presence of a rhamnolipid biosurfactant. Results showed that rhamnolipids caused an overall loss in cellular fatty acid content. Loss of fatty acids was due to release of LPS from the outer membrane, as demonstrated by 2-keto-3-deoxyoctonic acid and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis and further confirmed by scanning electron microscopy. The amount of LPS loss was found to be dependent on rhamnolipid concentration, but significant loss occurred even at concentrations less than the critical micelle concentration. We conclude that rhamnolipid-induced LPS release is the probable mechanism of enhanced cell surface hydrophobicity.Cell surface properties result from the unique chemical structure of the cell surface. In the case of a gram-negative bacterium such as Pseudomonas aeruginosa, this structure is the outer membrane, the outer leaflet of which is primarily composed of lipopolysaccharide (LPS). The outer leaflet contains LPS molecules which are composed of three components (25). The first is the lipid A tail which is anchored into the hydrophobic region of the outer membrane. The second is the core oligosaccharide, which contains a unique eight-carbon sugar called 2-keto-3-deoxyoctonic acid (KDO). The core oligosaccharide is connected to the lipid A tail through its reducing end and is positioned at the surface of the membrane in a manner analogous to the glycerol-phosphate head group of a phospholipid. The core oligosaccharide is negatively charged, and the association of adjacent LPS molecules is stabilized by Mg 2ϩ ions at the membrane surface. The third component of LPS is the O antigen which consists of 15 to 20 repeating mon...

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“…Loss of these cations from the cell wall could alter the structure. Rogers et al (14) showed that incubation of P. aeruginosa in EDTA caused the release of protein and lipopolysaccharide from the cell wall. It is suggested that TRIEN dihydrochloride may be acting in a manner similar to that of EDTA by causing an increase in cell permeability, thus allowing gentamicin easier access to its site of action in the cell; or (ii) it is possible that TRIEN dihydrochloride binds divalent cations in the medium only, thus preventing incorporation of the cations into the cell wall.…”

Section: Discussionmentioning

confidence: 99%

“…Studies have shown that the chelating agent, ethylenediaminetetraacetic acid (EDTA), increases the susceptibility of P. aeruginosa to various antibiotics in vitro (1,17). EDTA has been shown to increase cell wall permeability by removal of calcium, which is involved in essential cross-linkages and cell wall integrity (5,(7)(8)(9)14). However, due to the toxic properties of EDTA, its use in systemic therapy of P. aeruginosa infections has been limited (2).…”

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confidence: 99%

Effect of Triethylenetetramine Dihydrochloride on the Antibiotic Susceptibility of Pseudomonas aeruginosa

Light

Riggs

1978

Antimicrob Agents Chemother

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Recently, Pseudomonas aeruginosa has become a major problem for both patients and clinicians. Its increased prevalence in morbidity and mortality has been greatly complicated by its resistance to several antibiotic agents. Investigators have searched for both intrinsic and extrinsic factors which may be responsible for this antibiotic resistance (3,4,10,12,16). Many strains of P. aeruginosa may possess a cell wall which acts as a permeability barrier for antibiotic penetration (13). Studies have shown that the chelating agent, ethylenediaminetetraacetic acid (EDTA), increases the susceptibility of P. aeruginosa to various antibiotics in vitro (1, 17). EDTA has been shown to increase cell wall permeability by removal of calcium, which is involved in essential cross-linkages and cell wall integrity (5,(7)(8)(9)14). However, due to the toxic properties of EDTA, its use in systemic therapy of P. aeruginosa infections has been limited (2). In contrast to EDTA, triethylenetetramine dihydrochloride (TRIEN dihydrochloride) has been shown to be a chelating agent of low toxicity (6). In addition, the compound has been noted to enhance the activity of carbenicillin against P. aeruginosa (15). The purpose of this study was to determine the efficacy of TRIEN dihydrochloride in enhancing the susceptibility of P. aeruginosa to carbenicillin and gentamicin. In a similar manner this experiment was performed in TSB containing 50% serum (vol/vol), which was designated TSB-50S. The concentration of TRIEN dihydrochloride was increased to 0.0100 M in these experiments because at lower concentrations when serum was added to the growth medium, there was no effect on the MIC of the antibiotic. This higher con-

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Characterization of a protein-lipopolysaccharide complex released from cell walls of Pseudomonas aeruginosa by ethylenediaminetetraacetic acid

Cited by 98 publications

References 4 publications

Penicillin-Resistant Mechanisms in Pseudomonas aeruginosa : Binding of Penicillin to Pseudomonas aeruginosa KM 338

Penicillin-Resistant Mechanisms in Pseudomonas aeruginosa : Binding of Penicillin to Pseudomonas aeruginosa KM 338

Rhamnolipid-Induced Removal of Lipopolysaccharide from Pseudomonas aeruginosa : Effect on Cell Surface Properties and Interaction with Hydrophobic Substrates

Effect of Triethylenetetramine Dihydrochloride on the Antibiotic Susceptibility of Pseudomonas aeruginosa

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