Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gram-negative enteric bacteria are enveloped by two membrane systems. The inner or cytoplasmic membrane is responsible for the major metabolic functions including biosynthetic activities, while the major known functions of the outer membrane are primarily physical: it contains receptors for bacteriophages and bacteriocins; it contributes to the maintenance of cell shape; and it controls access of nutrient solutes and agents such as antibiotics and detergents to the cytoplasmic membrane. Several investigations have indicated that mobility of membrane components, particularly lipopolysaccharide, is essential for biogenesis of the outer membrane, and is a primary event in phage infection. To define more accurately the fluid dynamic properties of the outer membrane as related to function, we have now developed the capability to measure lateral diffusion coefficients in vivo of rhodaminated G30 lipopolysaccharide fused into Salmonella typhimurium G30A filamentous bacteria. The method used extends the FRAP procedure (fluorescence redistribution after photobleaching) to bacteria and the results demonstrate rapid diffusion of lipopolysaccharide (D = 2.0 +/- 0.9 x 10(-10) cm2s-1) over micrometre distances.
 ...
PMID:Lateral diffusion of lipopolysaccharide in the outer membrane of Salmonella typhimurium. 699 Feb 76

We have studied the DNA sequence elements of the murine MHC class II A beta gene involved in transcriptional regulation in macrophages. For this study, the A beta promoter was fused to the human growth hormone gene and transfected into bone marrow-derived macrophages. These macrophages were stimulated by interferon-gamma (IFN-gamma), after which cellular RNA was assayed for the amount of human growth hormone transcripts. A -146 to +14 fragment of the A beta promoter was found to be sufficient to confer positive regulation by IFN-gamma. Induction was suppressed by bacterial lipopolysaccharide, tumor necrosis factor (TNF-alpha), or maley-lated bovine serum albumin. Substitution mutations were made within each of the conserved sequence elements of the promoter as well as within the spacer regions between these elements. All four conserved sequences found in class II promoters, the H, X1, X2, and Y elements, were found to be essential for promoter activation in macrophages.
 ...
PMID:Sequence elements required for function of the MHC class II A beta gene promoter in murine macrophages. 749 22

Interferon gamma (IFN-gamma) interacts synergistically with bacterial lipopolysaccharide (LPS) to induce transcription of iNOS, the isoform of nitric oxide synthase whose activity is independent of elevated Ca2+ and exogenous calmodulin. To define a cis-acting element mediating IFN-gamma-dependent synergy, we made deletions in iNOS promoter constructs fused to reporter genes, transfected RAW 264.7 macrophages, and treated the cells with IFN-gamma and/or LPS. This analysis implicated the region from positions -951 to -911, a cluster of four enhancer elements known to bind IFN-gamma-responsive transcription factors, including an interferon regulatory factor binding site (IRF-E) at nucleotides -913 to -923. Site-specific substitution of two conserved nucleotides within IRF-E in the context of the full-length iNOS promoter ablated IFN-gamma's contribution to synergistic enhancement of transcription. Electromobility shift assays performed with a probe containing IRF-E revealed the existence of a complex in nuclei of RAW 264.7 macrophages that was present only after treatment with IFN-gamma, which reacted specifically with anti-IRF-1 immunoglobulin G and which included a species migrating at 40-45 kD, consistent with the apparent molecular weight of murine IRF-1. Thus, the synergistic contribution of IFN-gamma to transcription of iNOS in RAW 264.7 macrophages requires that IRF-1 bind to IRF-E in the iNOS promoter. In conjunction with the work of Kamijo et al. (Kamijo, R., H. Harada, T. Matsuyama, M. Bosland, J. Gerecitano, D. Shapiro, J. Le, K. S. Im, T. Kimura, S. Green et al. 1994. Science [Wash. DC]. 263:1612), these findings identify iNOS as the first gene that requires IRF-1 for IFN-gamma-dependent transcriptional regulation.
 ...
PMID:Role of interferon regulatory factor 1 in induction of nitric oxide synthase. 752 Apr 78

Serum amyloid A (SAA) protein synthesis is highly induced in acute inflammatory conditions. Such induction process is primarily regulated at the transcriptional level and large amount of SAA mRNA has been found to accumulate in rabbit liver during acute inflammation. To identify the promoter element(s) involved in inducible transcription of SAA, a 5' flanking region of this gene has been fused to a reporter chloramphenicol acetyl transferase (CAT) gene and transfected into BNL liver cells. This DNA is capable of inducing synthesis of the reporter gene in response to lipopolysaccharide-stimulated monocyte-derived conditioned medium. Deletion analyses have shown that a region from -135 to -78 that contains a putative NF-kappa B element is responsible for the inducible function of the promoter. Gel shift assay has detected DNA-binding activity in the induced cells that appear to interact with the potential NF-kappa B element located within -112 to -78 of the SAA gene. Similar factor(s) have also been detected in the lipopolysaccharide-treated rabbit liver which is highly active in transcribing SAA mRNA. Appearance of these factors in acute-phase induced animals and their binding to the NF-kappa B-like element in the SAA proximal promoter region correlated with SAA mRNA synthesis suggests functional role of this promoter element in SAA gene expression under LPS-induced acute-phase condition.
 ...
PMID:Functional NF-kappa B element in rabbit serum amyloid A gene and its role in acute phase induction. 768 47

Six different prepared mutant strains of Shigella dysenteriae type 1 with various combinations of 'core' plasmids of 140, 6, and 2 Mdal, were cultivated separately and their lipopolysaccharide (LPS) samples were isolated, which on delipidation afforded polysaccharides and oligosaccharides. The LPS and prepared O-antigen polysaccharides were subjected to acid hydrolysis, and the constituent sugars were analysed by paper chromatography and gas liquid chromatography (GLC), using CP Sil 8 CB fused silica capillary column equipped with a flame ionization detector. The mutant strains, harbouring the 6 Mdal plasmid, contained rhamnose, galactose, and N-acetyl glucosamine in their O-antigen polysaccharides with a minor variation in the relative proportions of these sugar constituents as compared to those of the control strain. The sugar composition of the O-antigen polysaccharides prepared from the mutant stains, without the 6 Mdal plasmid but containing 2 or 140 Mdal plasmid, contained galactose and N-acetyl glucosamine but no rhamnose. However, mutant strains with none of the core plasmids contained traces of rhamnose and were devoid of N-acetyl glucosamine, but contained heptose. These results suggest that 6 Mdal plasmid is essentially required for the complete synthesis of O-antigen polysaccharides. However, the 140 and 2 Mdal plasmids might also have an association with synthesis of carbohydrate composition of the O-antigen in S. dysenteriae type 1.
 ...
PMID:Association of plasmids with the carbohydrate composition of the O-antigen in Shigella dysenteriae type 1. 769 22

Immunochemical specificity of lipopolysaccharide and the molecular property of the gene encoding the fimbrilin (fimA) of Porphyromonas gingivalis strains were examined using 'fimbriated' strains 381 and HG564 and 'non-fimbriated' strains 381FL and W50. Lipopolysaccharide from strains 381, 381FL and HG564 reacted with monoclonal antibody raised to lipopolysaccharide from strain 381 to give a fused precipitin band by the immunodiffusion test. However, silver staining and Western blotting of lipopolysaccharide clearly revealed a difference in profile of bands between strains 381 and 381FL. On the other hand, lipopolysaccharide from W50 formed another precipitin band and reacted with the antibody, but only at higher concentrations of lipopolysaccharide. The fimA genes in these strains were amplified by polymerase chain reaction and cloned. Sequencing of the fimA gene revealed that the fimA(W50) was almost identical to fimA(HG564), but a notable difference was observed at the start codon of the open reading frame, while the fimA(381FL) was considerably different from fimA of other strains and its open reading frame was found to be missing. These results indicate that the molecular structure of the fimA genes of these strains is not homologous, indicating that molecular modifications in the fimA gene should occur during in vitro passages and maintenance of strains of P. gingivalis in laboratories.
 ...
PMID:Inconsistency between the fimbrilin gene and the antigenicity of lipopolysaccharides in selected strains of Porphyromonas gingivalis. 785 39

An anti-idiotype antibody has been developed which is specific for idiotypic determinants of a BALB/c mouse IgG3 monoclonal antibody (MAbY1-4A6) directed against the inner-core Kdo region of lipopolysaccharide (LPS). Armenian hamsters were immunized with MAbY1-4A6 and splenocytes from immunized animals fused with Sp2/0 myeloma cells. Eight clones secreting antibodies that bound to MAbY1-4A6, but not control IgG3, were identified and subcloned. Culture supernatants from one hybridoma, termed MAb4G2, contain monoclonal antibody that binds to the variable region of MAbY1-4A6 and dose-dependently inhibits binding of MAbY1-4A6 to Re chemotype rough mutant LPS (Re-LPS). This antibody also inhibits binding of three additional mouse monoclonal antibodies specific for the inner-core of Re-LPS. MAb4G2 also recognizes a significant proportion of antibodies present in polyclonal R-chemotype antisera generated in mice (Re-LPS) and rabbits (J5 Rc-LPS). Mice and hamsters immunized with MAb4G2 or Re-LPS generate antibodies which cross-react with both immunogens. Cumulatively, these data suggest that MAb4G2 can function as an internal image of the Kdo-specific monoclonal antibody, MAbY1-4A6, mimicking the antigenic structure and immunogenicity of a portion of the LPS inner-core Kdo region.
 ...
PMID:Development of an anti-idiotype monoclonal antibody mimicking the structure of lipopolysaccharide (LPS) inner-core determinants. 825 5

Interaction between Carcinoscorpius rotundicauda amoebocytes and Escherichia coli or Staphylococcus aureus has shown that whilst E. coli was observed to lyse, S. aureus remained intact. The heavily granulated amoebocytes were activated by the lipopolysaccharide of E. coli to undergo dramatic morphological changes with time, leading to degranulation which caused lysis of the E. coli. Degranulation of the amoebocytes involved maturation of the larger electron dense granules (0.7-2.0 micron) which were apparently mobilised towards the cell membrane whilst undergoing a loss in electron density. Some of these larger granules were expelled at 15-30 min while other intracellular granules underwent further degranulation, where parallel filaments appearing like microtubules were evident, giving the granules a striated and less dense form. By 60 min, there was complete depolymerisation of the microtubular filaments giving rise to undefined, fused and homogeneously packed striations and particulate material in the cytoplasm; the smaller electron dense granules (0.3-0.7 micron) remained unchanged. This asynchronous degranulation and preferential expulsion of granules from only some amoebocytes while maintaining others intact, implies that the horseshoe crab has safeguards in its defence mechanism, hence ensuring its continued survival as a 'living fossil'.
 ...
PMID:Morphological changes of Carcinoscorpius rotundicauda amoebocyte and Escherichia coli during their interaction. 837 92

The tumor necrosis factor (TNF-alpha or TNF) gene is activated by both lipopolysaccharide (LPS) and cycloheximide in RAW 264.7 macrophages, whereas neither stimulus activates the gene in 3T3 fibroblasts. Moreover, the pattern of CG methylation within the TNF gene is readily distinguishable in DNA derived from cells of these two types. These findings would suggest that the TNF gene has been rendered inaccessible to transcription in the 3T3 cell environment. When RAW 264.7 cells are fused with 3T3 cells, an immortal pentaploid hybrid results. In the hybrid cell, all three TNF genes contributed by the RAW 264.7 cell parent become highly methylated according to the pattern observed in the 3T3 cell parent. Permanently transfected chloramphenicol acetyl transferase (CAT) reporter constructs, bearing 2.2 kb of upstream sequence (including the entire TNF promoter and 5'-untranslated region [UTR]) as well as 1.0 kb of downstream sequence (including the entire TNF 3'-UTR and termination sequence), are accessible in both RAW 264.7 cells and 3T3 cells, but are silenced in transition from the RAW 264.7 cell to the hybrid cell environment. Moreover, the endotoxin signaling pathway is abrogated, as assessed by transient transfection of hybrid cells with LPS-responsive CAT reporter constructs. It would therefore appear that the fusion of 3T3 cells and RAW 264.7 cells activates a system that silences the TNF gene, as well as the LPS signaling pathway. This system may operate to determine TNF gene accessibility and LPS responsiveness in the course of cell differentiation. The DNA sequences targeted within the TNF gene are included in the CAT reporter construct; therefore, the silencing element has been circumscribed to a region of DNA 3.2 kb in length.
 ...
PMID:Extinction of the tumor necrosis factor locus, and of genes encoding the lipopolysaccharide signaling pathway. 847 13

CD14, a glycosylphosphatidylinositol-anchored protein on the surface of monocytes, macrophages, and polymorphonuclear leukocytes, is a receptor for lipopolysaccharide (LPS). It was recently reported that an N-terminal 152-amino-acid fragment of soluble CD14 was an active soluble lipopolysaccharide receptor (T. S. -C. Juan, M. J. Kelley, D. A. Johnson, L. A. Busse, E. Hailman, S. D. Wright, and H. S. Lichenstein, J. Biol. Chem. 270:1382-1387, 1995). To determine whether the N-terminal half of the membrane CD14 was a functional LPS receptor on the cell membrane, we engineered a chimeric gene coding for amino acids 1 to 151 of CD14 fused to the C-terminal region of decay-accelerating factor and expressed it in Chinese hamster ovary cells and 70Z/3 cells. We found that the chimeric, truncated CD14 is a fully functional LPS receptor in both cell lines.
 ...
PMID:The N-terminal half of membrane CD14 is a functional cellular lipopolysaccharide receptor. 855 Feb 21


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>