Release of lipopolysaccharide by EDTA treatment of E., coli

Leive, Loretta

doi:10.1016/0006-291x(65)90191-9

Cited by 448 publications

(289 citation statements)

References 13 publications

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“…Treatment of gram-negative bacteria with ethylenediaminetetraacetic acid (EDTA) results in a general increase in permeability (14), which leads to increased sensitivity to penicillins (22). This effect of EDTA can be reversed with multivalent cations (1).…”

Section: Resultsmentioning

confidence: 99%

Correlation Between the Binding of β-Lactam Antibiotics to Staphylococcus aureus and Their Physical-Chemical Properties

Retsema

Ray

1972

Antimicrob Agents Chemother

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The rate of 14 C-benzylpenicillin (penicillin G) binding to Staphylococcus aureus Oxford cells increased with increasing hydrogen ion concentration. The extent of inhibition of 14 C-penicillin G binding caused by a competing 12 C-β-lactam antibiotic is a function of hydrogen ion concentration and can be correlated both with net charge of a competing 12 C-molecule and net charge of the S. aureus cell at a given p H. The ability of a β-lactam antibiotic to compete for 14 C-penicillin G-binding sites can generally be correlated with its hydrophobic nature. It is proposed that, although semisynthetic cephalosporins are chemically less reactive than penicillins, they are superior to benzylpenicillin in their ability to permeate the outer surface of the Staphylococcus cell wall and irreversibly bind to reactive sites.

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Section: Resultsmentioning

confidence: 99%

Correlation Between the Binding of β-Lactam Antibiotics to Staphylococcus aureus and Their Physical-Chemical Properties

Retsema

Ray

1972

Antimicrob Agents Chemother

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“…LPS defects caused either by defective LPS biogenesis or by the release of LPS molecules from the OM during EDTA treatment result in the translocation of phospholipids to the outer leaf let of the OM (16,19,43). This translocation activates the OM enzyme PagP, which transfers a palmitate group from a phospholipid to lipid A (44), converting wild-type, hexa-acyl lipid A to hepta-acyl lipid A (45).…”

Section: Depletion Of Lptf And/or Lptg Leads To Altered Lps But Does Notmentioning

confidence: 99%

Identification of two inner-membrane proteins required for the transport of lipopolysaccharide to the outer membrane of Escherichia coli

Ruiz

Gronenberg

Kahne

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

241

277

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The outer membrane (OM) of most Gram-negative bacteria contains lipopolysaccharide (LPS) in the outer leaflet. LPS, or endotoxin, is a molecule of important biological activities. In the host, LPS elicits a potent immune response, while in the bacterium, it plays a crucial role by establishing a barrier to limit entry of hydrophobic molecules. Before LPS is assembled at the OM, it must be synthesized at the inner membrane (IM) and transported across the aqueous periplasmic compartment. Much is known about the biosynthesis of LPS but, until recently, little was known about its transport and assembly. We applied a reductionist bioinformatic approach that takes advantage of the small size of the proteome of the Gram-negative endosymbiont Blochmannia floridanus to search for novel factors involved in OM biogenesis. This led to the discovery of two essential Escherichia coli IM proteins of unknown function, YjgP and YjgQ, which are required for the transport of LPS to the cell surface. We propose that these two proteins, which we have renamed LptF and LptG, respectively, are the missing transmembrane components of the ABC transporter that, together with LptB, functions to extract LPS from the IM en route to the OM.ABC transporter ͉ bioinformatics ͉ endosymbiont ͉ membrane biogenesis T he hallmark of Gram-negative bacteria is the presence of two extracytoplasmic membranes: the inner and outer membranes. The inner membrane (IM), which surrounds the cytoplasm, is separated from the outer membrane (OM) by an aqueous compartment known as the periplasm (1, 2). The IM is composed of phospholipids, integral transmembrane (TM) proteins that span the IM with ␣-helical TM domains, and lipoproteins (3, 4). In contrast, the OM is typically an asymmetric lipid bilayer where the inner leaflet is composed of phospholipids and the outer leaflet is composed mainly of lipopolysaccharide (LPS) (5). In addition, the OM contains lipoproteins and integral outer membrane proteins (OMPs), most of which span the OM via antiparallel ␤-sheets that fold into ␤-barrels (4, 6). Although some Gram-negative bacteria lack LPS and in others LPS is not essential (7), LPS is essential in Escherichia coli, Salmonella, and probably many other bacteria.In E. coli, the main function of the OM is to serve as a selective permeability barrier against many toxic chemicals, such as detergents and antibiotics (1). Porin proteins in the OM control permeability to hydrophilic molecules, but unlike typical phospholipid bilayers, the OM is quite impermeable to hydrophobic molecules, mainly because of LPS (1). For the OM to serve as a barrier, all OM components must be assembled properly. None of the components of the OM are synthesized in situ, so they must be transported to the OM from their site of synthesis. All OMPs and lipoproteins are made in the cytoplasm and cross the IM through the Sec translocon (3). After their signal sequence is removed, OMPs are thought to travel across the periplasm aided by chaperones that deliver them to the OM Bam complex (␤-barrel a...

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“…However, by disturbing LPS-LPS interactions, e.g., by EDTA treatment (29), LPS can be released from the outer membrane into the external environment. In previous studies, it was shown that membrane-bound LPS has a lower proinflammatory cytokineinducing activity than soluble LPS aggregates (36,42), probably due to the better accessibility of LPS in soluble aggregates for extraction and subsequent transfer by LBP/CD14 to the TLR4/MD-2 complex.…”

Section: Deacylation Of Lps Influences Its Release From B Pertussis mentioning

confidence: 99%

Expression of the Lipopolysaccharide-Modifying Enzymes PagP and PagL Modulates the Endotoxic Activity ofBordetella pertussis

Geurtsen¹,

Steeghs

Hamstra³

et al. 2006

Infect Immun

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Lipopolysaccharide (LPS) is one of the major constituents of the gram-negative bacterial cell envelope. Its endotoxic activity causes the relatively high reactogenicity of whole-cell vaccines. Several bacteria harbor LPS-modifying enzymes that modulate the endotoxic activity of the LPS. Here we evaluated whether two such enzymes, i.e., PagP and PagL, could be useful tools for the development of an improved and less reactogenic whole-cell pertussis vaccine. We showed that expression of PagP and PagL in Bordetella pertussis leads to increased and decreased endotoxic activity of the LPS, respectively. As expected, PagP activity also resulted in increased endotoxic activity of whole bacterial cells. However, more unexpectedly, this was also the case for PagL. This paradoxical result may be explained, in part, by an increased release of LPS, which we observed in the PagL-expressing cells.

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Release of lipopolysaccharide by EDTA treatment of E., coli

Cited by 448 publications

References 13 publications

Correlation Between the Binding of β-Lactam Antibiotics to Staphylococcus aureus and Their Physical-Chemical Properties

Correlation Between the Binding of β-Lactam Antibiotics to Staphylococcus aureus and Their Physical-Chemical Properties

Identification of two inner-membrane proteins required for the transport of lipopolysaccharide to the outer membrane of Escherichia coli

Expression of the Lipopolysaccharide-Modifying Enzymes PagP and PagL Modulates the Endotoxic Activity ofBordetella pertussis

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