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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Atomic absorption spectroscopy of isolated native and EDTA-modified (lipopolysaccharide-depleted) outer membrane revealed trace amounts of potassium, manganese, and iron (1.0-7.0 nmol/mg dry weight outer membrane). Sodium, magnesium, and calcium were approximately one order of magnitude more plentiful, but EDTA-modified outer membrane was deficient in calcium. When metal-binding assays were conducted to find the binding capacity of native and EDTA-modified outer membrane, potassium bound poorly compared with sodium. However, there was no difference in the binding of these ions between the OM preparations. In contrast, reduced amounts of magnesium, calcium, manganese, and iron III bound to the EDTA-modified OM. Partitioning of intact cells in a biphasic dextran-polyethyleneglycol system indicated that the reduced lipopolysaccharide content of the EDTA-modified outer membrane increased the hydrophobicity of the cell surface. Exposure of control and EDTA-treated cells to divalent metal salt solutions before phase partitioning also increased cell surface hydrophobicity. Freeze-etching showed that sodium ions had no effect on the membrane fractures observed in control cells, but with EDTA-treated cells, this cation increased the occurrence of small outer membrane fractures (plateaus) which are characteristic of EDTA treatment. Both magnesium and manganese increased the frequency of outer membrane cleavage in control cells, whereas calcium did not. In contrast, all three divalent metallic ions increased the frequency and extent of cleavage in the outer membrane of EDTA-treated cells.
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PMID:Physicochemical roles of soluble metal cations in the outer membrane of Escherichia coli K-12. 309 Dec 29

This study was carried out to determine whether bone might be a source of hemopoietic growth factors. Both neonatal murine calvaria and primary cultures of cells isolated from calvaria released, upon stimulation with lipopolysaccharide, an activity that stimulated the growth of the interleukin (IL) 3-dependent cell lines, 32D cl, 123, and NSF 60. Upon gel filtration, this activity eluted with a molecular weight of 30,000 kDa. Further characterization, however, revealed that the major activity in conditioned medium was not IL 3. Activity was absorbed by DEAE-Sephacel at low salt concentration, whereas IL 3 does not adhere. Furthermore, an IL 3-specific antiserum did not neutralize the activity from cells and only partly neutralized the activity generated by whole calvaria. After gel filtration, the 30-kDa activity stimulated the growth of very large colonies in semisolid medium consisting mainly of granulocytes with the remainder being macrophages. No colony types belonging to other hemopoietic lineages were found, indicating, again, that the activity was not identical to IL 3. Subsequently, conditioned medium was fractionated by hydrophobic chromatography on Phenyl-Sepharose CL-4B, yielding two peaks of activity. Neutralization of activity with antisera to granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL 3 and use of colony assays showed that medium conditioned by whole calvaria contained GM-CSF and granulocyte CSF (G-CSF) in similar amounts together with a little IL 3, and medium conditioned with calvaria cells contained GM-CSF and little G-CSF. We conclude that bone releases hemopoietic growth factors that could contribute both to hemopoiesis and to the recruitment of osteoclasts from progenitors resident in the adjacent marrow.
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PMID:Production of hemopoietic growth factors by bone tissue and bone cells in culture. 326 92

Exposure of rats to high concentrations of oxygen (greater than 95%) at 1 ATA pressure (101 kPa) is lethal within three days. Rats treated with a small dose of endotoxin are protected against these lethal effects of hyperoxia. Recently, we found that the lysine salt of acetylsalicylic acid antagonises this protective action of endotoxin. This suggests that prostaglandin metabolism plays an important role in the protective action of endotoxin against pulmonary oxygen toxicity. Therefore, we measured the plasma levels of 6KPGF1 alpha, a stable degradation product of prostacyclin (PGI2), PGE2 and thromboxane B2, the stable degradation product of thromboxane A2, in rats exposed to air or greater than 95% oxygen for 48 hours. We compared these with the plasma levels of rats treated with endotoxin (Salmonella typhimurium lipopolysaccharide 1 mg/kg) and exposed to air or greater than 95% oxygen for 48 hours. We found that exposure of rats to greater than 95% oxygen for 48 hours leads to a significant rise in the 6KPGF1 alpha levels. Rats exposed to greater than 95% oxygen for 48 hours and treated with endotoxin had significantly higher PGE2 and significantly lower 6KPGF1 alpha plasma levels than saline-treated rats exposed to greater than 95% oxygen for 48 hours.
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PMID:Endotoxin protection against pulmonary oxygen toxicity and plasma prostaglandin levels in the rat. 347 92

We examined Escherichia coli K-12 lipopolysaccharide (LPS), which is known to be an R-form LPS, for its ability to form a hexagonal lattice structure in vitro. The LPS from E. coli K-12 strain JE1011 did not form a hexagonal lattice structure when it was precipitated by addition of two volumes of 10 mM MgCl2-ethanol, but it did form such a structure when it was electrodialyzed and then converted to the magnesium or calcium salt form. The lattice constant of the magnesium salt form was 15.2 +/- 0.3 nm and that of the calcium salt form 18.5 +/- 0.3 nm. Since prior treatment of the LPS with proteinase K in the presence of sodium dodecyl sulfate did not affect its capability of hexagonal assembly, the lattice formation by the LPS does not require the presence of proteins.
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PMID:In vitro hexagonal assembly of lipopolysaccharide of Escherichia coli K-12. 354 25

The aggregate structure of lipopolysaccharide isolated from an Re strain of Escherichia coli was examined at different pH values using small angle neutron scattering. At pH values of 6 and 7.4, angle-averaged scattering of the sodium salt of this isolate was consistent with randomly coiled tubular micelles approximately 100 A in diameter. At pH 9.1, however, Kratky analysis of the scattering data was distinctly different and consistent with pairing of uniform tubular micelle sections of length 1440 and 110 A in diameter. Contrast variation measurements of the micelles yielded an average micellar weight of the sample at pH 9.1 of approximately 1.11 X 10(7) daltons and suggested that the aggregates were tubular micelles of size and length similar to that derived from the scattering intensity data. Anisotropic scattering patterns of samples under shear indicated a rigidification of the micelles as the pH was increased to 9.1 and the temperature decreased from 25 to 10 degrees C. The rotational diffusion constants deduced from the observed shear anisotropy indicate that the structure at pH 9.1 must have smallest and largest dimensions which differ by at least an order of magnitude, ruling out spherical or moderately ellipsoidal structures. Analysis of the shear rate needed to induce anisotropic scattering indicated that the stiffness length of the micelles at pH 9.1 was approximately 1000 A and decreased at higher and lower pH values.
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PMID:Neutron scattering analysis of bacterial lipopolysaccharide phase structure. Changes at high pH. 354 14

Various antigenic extracts of the CU strain of Pasteurella multocida were prepared to determine their suitability as plate antigens for use in the enzyme-linked immunosorbent assay (ELISA) for the detection of fowl cholera antibodies. Antisera from two separate broiler breeder flocks with known fowl-cholera-vaccination histories were collected just before the birds were challenged with virulent strain X-73 P. multocida. A potassium thiocyanate (KSCN)-extracted antigen, a capsular (CAP) antigen, a lipopolysaccharide-protein antigen, and heat-stable, salt-soluble antigen were all suitable as ELISA plate-coating antigens. Filtered and unfiltered sonicates of the CU strain of P. multocida were also suitable ELISA plate antigens. The results suggested that different plate antigens were detecting different populations of antibodies formed in response to fowl cholera vaccinations. When antibody titers were correlated with survival after challenge, the KSCN and the CAP plate antigens placed more nonsurvivors into low-antibody-titer ranges and more survivors (protected birds) into the high-antibody-titer ranges than the other plate antigens.
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PMID:Comparison of various antigens and their ability to detect protective antibodies against Pasteurella multocida using enzyme-linked immunosorbent assay. 376 14

During their initial association with plant hosts, pathogenic bacteria interact with plant cell walls. The results of this interaction appear to determine whether bacterial multiplication will take place. With one group of bacterial plant pathogens (e.g. Agrobacterium tumefaciens), attachment to the host surface appears essential for pathogenesis. With another group (e.g. Pseudomonas solanacearum), only those strains that do not attach to the host cell wall are able to multiply in the intercellular spaces. Attachment of many incompatible strains to tobacco mesophyll cell walls leads to a rapid hypersensitive response (HR) and a drastic reduction in bacterial multiplication. Our working hypothesis is that these differences in host response to strains of P. solanacearum are the result of a recognition response in which surface components of both host and pathogen play important roles. Our approach is based on the use of spontaneous or transposon (Tn5)-generated mutants of strains K60 (virulent) and B1 (avirulent) that differ in surface components and in their ability to attach to host cells and to induce the HR. A study of the surface components of bacterial and tobacco cell walls has led to the tentative conclusion that bacterial lipopolysaccharide (LPS) and plant hydroxyproline-rich glycoproteins mediate initial attachment, apparently as a result of charge-charge interaction. This initial attachment is reversed by high salt concentrations during the first 15 min, but not thereafter. Firm attachment appears to depend on hydrophobic interactions mediated by bacterial pili. At the normal ionic strength of intercellular fluids, extracellular polysaccharide (EPS) appears to inhibit only the pili-mediated attachment. Several HR- mutants of strain B1 have been obtained by Tn5 insertion, but they remain avirulent on tobacco. We are examining the EPS, LPS and pili production, and the attachment characteristics of these strains.
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PMID:Surface components involved in bacterial pathogen-plant host recognition. 386 76

The binding characteristics of partially purified glucocorticoid receptor complexes from hormone sensitive, non-differentiating BCL1 cells to sequentially deproteinized BCL1 chromatin-cellulose was investigated. [3H]Triamcinolone acetonide (TA)-receptor complexes were purified (approx. 30-fold) from DEAE-cellulose columns by salt elution which allowed receptor activation only in the absence of molybdate. Addition of 10 mM molybdate completely blocked salt activation. The binding pattern of the activated [3H]TA-receptor complexes to chromatin-cellulose extracted with 0-8 M guanidine hydrochloride revealed three regions of increased binding activity (acceptor sites), at 2, 5 and 7 M guanidine hydrochloride. Acceptor site binding was markedly reduced for chromatin extracted with 3, 6 and 8 M guanidine hydrochloride. Non-activated receptor complexes demonstrated very low binding to deproteinized chromatin. It was also shown that chromatin binding required glucocorticoid receptors and that free ligand or ligand bound to other proteins did not bind significantly to chromatin. In addition, binding of [3H]TA-receptor complexes to partially deproteinized chromatin was competable by unlabeled TA-receptor complexes. Scatchard analysis demonstrated that chromatin from non-differentiating BCL1 cells possesses multiple, high-affinity binding sites which differ in their affinity for the glucocorticoid receptor. Partially deproteinized chromatin from lipopolysaccharide-stimulated BCL1 cells demonstrated a different pattern of receptor binding, i.e., receptor binding was significantly greater to chromatin previously extracted with 6-8 M guanidine hydrochloride. These results suggest that differentiation alters the state of chromatin and the interaction of non-histone protein/DNA acceptor sites with glucocorticoid receptors. These alterations may play a role in the acquisition of hormone resistance.
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PMID:Binding of [3H]triamcinolone acetonide-receptor complexes to chromatin from the B-cell leukemia line, BCL1. 387 35

We extracted an R-form lipopolysaccharide (LPS) by the phenol-water method from Klebsiella sp. strain LEN-111 (O3-:KI-) and followed the changes in ultrastructure of the LPS during the extraction procedure. When the LPS was obtained from the water phase of an extract by addition of 2 volumes of 10 mM MgCI2-ethanol, it consisted of membrane pieces with a hexagonal lattice structure with a lattice constant of 14 to 15 nm. The lattice structure of the LPS was disrupted into short rods with sodium dodecyl sulfate, but the same hexagonal lattice structure was again formed by precipitation with 2 volumes of 10 mM MgCI2-ethanol. The LPS preparation after two cycles of treatment by the phenol-water method, which contained no detectable amounts of proteins, kept an unaltered ability to form the hexagonal lattice structure. Extensive treatment with pronase and extraction with chloroform did not impair the ability of the LPS preparation to form the lattice structure. When the other salts, NaCI, CaCI2 or Zn(CH3COO)2, were used for precipitation of the LPS with ethanol in place of MgCI2, the LPS did not form the hexagonal lattice structure. However, if the LPS precipitated with NaCI-ethanol was converted to the magnesium salt form after it was electrodialyzed, it formed the same hexagonal lattice structure as the LPS precipitated with MgCI2-ethanol. From these results, it was concluded that the R-form LPS has the ability of in vitro self-assembly into a hexagonal lattice structure in the presence of Mg2+ without the help of other components such as proteins and free lipids from outer membrane.
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PMID:Formation of a hexagonal lattice structure by an R-form lipopolysaccharide of Klebsiella sp. 399 76

Various uniform salt forms of an R-form lipopolysaccharide (LPS) extracted from Klebsiella strain LEN-111 (O3-:K1-) were prepared and their ultrastructure was examined. The LPS, which was extracted by the phenol-water method, freed from contamination with RNA by treatment with RNase, and precipitated by addition of two volumes of 10 mM MgCl2-ethanol, was used as the original preparation for uniform salt forms. The original LPS preparation formed a hexagonal lattice structure with a lattice constant of 14.9 +/- 0.2 nm. The LPS after electrodialysis retained the ability to form a hexagonal lattice structure, although its lattice constant was large (18.7 +/- 0.5 nm) and the lattice structure of the electrodialyzed LPS was labile at pH 8.0 in contrast to that of the original LPS preparation. The magnesium salt form of the LPS formed essentially the same ordered hexagonal lattice structure (lattice constant of 15.0 +/- 0.2 nm) as that of the original LPS preparation. The calcium and ammonium salt forms formed a hexagonal lattice structure, but the lattice constants of the calcium and ammonium salt forms were larger (18.6 +/- 0.6 nm and 19.3 +/- 0.4 nm, respectively) than that of the magnesium salt form. The sodium and potassium salt forms consisted of freely branching ribbon-like structures with an average width of 13 nm and an average thickness of 9 nm. The triethylamine salt form consisted principally of short rods (10 nm X 9-13 nm).
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PMID:Formation of a hexagonal lattice structure by an R-form lipopolysaccharide of Klebsiella: relationship between lattice formation and uniform salt forms. 409 71


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