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)

A lipopolysaccharide was isolated by extraction of Aspergillus flavus conidia with 45% phenol at 68-70 degrees C. Quantitative analysis revealed 7% nucleic acids, 5.5% proteins, 46% polysaccharides and 49% liquids, of which 12% were covalently bound. Glucose, mannose, galactose and fucose were detected as monosaccharide components of the polysaccharide moiety by gas chromatography; palmitic acid, stearic acid, oleic acid, linoleic acid and myristic acid were mainly present in the lipidic fraction. This material differs from the bacterial lipopolysaccharides, both in composition of the polysaccharide moiety and representation of fatty acids in the lipidic fraction.
 ...
PMID:A lipopolysaccharide from Aspergillus flavus conidia. 679 11

The effect of palmitic acid on the immune response of mice to sheep erythrocytes was studied. It was found to increase the number of background plaques in normal mice but it had no significant effect on primed cells. When given with antigen it functioned as a weak adjuvant but it had no effect on response of mouse lymphocytes to the mitogens phytohemagglutinin or bacterial lipopolysaccharide. While it is clear that palmitic acid does not have a profound effect on lymphocyte reactivity, it may have a subtle modulating influence on the immune system.
 ...
PMID:Influence of palmitic acid on mouse lymphocyte function in vivo and in vitro. 706 Nov 49

The htrB gene product of Haemophilus influenzae contributes to the toxicity of the lipooligosaccharide. The htrB gene encodes a 2-keto-3-deoxyoctulosonic acid-dependent acyltransferase which is responsible for myristic acid substitutions at the hydroxy moiety of lipid A beta-hydroxymyristic acid. Mass spectroscopic analysis has demonstrated that lipid A from an H. influenzae htrB mutant is predominantly tetraacyl and similar in structure to lipid IV(A), which has been shown to be nontoxic in animal models. We sought to construct a Salmonella typhimurium htrB mutant in order to investigate the contribution of htrB to virulence in a well-defined murine typhoid model of animal pathogenesis. To this end, an r- m+ galE mutS recD strain of S. typhimurium was constructed (MGS-7) and used in inter- and intrastrain transduction experiments with both coliphage P1 and Salmonella phage P22. The Escherichia coli htrB gene containing a mini-Tn10 insertion was transduced from E. coli MLK217 into S. typhimurium MGS-7 via phage P1 and subsequently via phage P22 into the virulent Salmonella strain SL1344. All S. typhimurium transductants showed phenotypes similar to those described for the E. coli htrB mutant. Mass spectrometric analysis of the crude lipid A fraction from the lipopolysaccharide of the S. typhimurium htrB mutant strain showed that for the dominant hexaacyl form, a lauric acid moiety was lost at one position on the lipid A and a palmitic acid moiety was added at another position; for the less abundant heptaacyl species, the lauric acid was replaced with palmitoleic acid.
 ...
PMID:Mutation of the htrB gene in a virulent Salmonella typhimurium strain by intergeneric transduction: strain construction and phenotypic characterization. 928 9

Neutrophils isolated from patients with bacterial infections or stimulated in vitro with lipopolysaccharide (LPS) produce a high resolution, lipid-dominated spectrum on 1H-NMR spectroscopy (May et al, 1993. J. Infect. Dis. 168: 386-392). We have investigated the origin of this lipid signal using NMR and chemical analyses of both whole neutrophils and purified plasma membranes. Plasma membranes from neutrophils that had been stimulated with 50 microg/ml LPS exhibited the high resolution 1H-NMR signal, and contained double the triacylglycerol (TAG) content of plasma membranes isolated from resting cells. Chemical analysis of the whole cells indicated that the TAG also increased at the cellular level (1.7-fold) after stimulation with LPS. Diradylglycerol increased 2- to 3-fold in both whole cells and plasma membranes after stimulation, but was only a minor component compared with TAG. The plasma membrane protein/phospholipid ratio increased 2.6-fold, whereas cholesterol (free and esterified) was unchanged. The membranes from LPS-stimulated neutrophils exhibited increased fluidity, as judged by increased merocyanine 540 binding, consistent with a 2-fold reduction in cholesterol/phospholipid ratio. LPS induced a shift in fatty acid content of whole cell polar lipids towards more oleic acid and less palmitic acid, whereas the neutral lipid fraction contained increased amounts of palmitic and stearic acids. The TAG fraction of plasma membrane lipids contained increased amounts of palmitic acid when prepared from cells stimulated with LPS. We conclude that the 1H-NMR signal in LPS-stimulated neutrophils arises from increased amounts of plasma membrane TAG with an elevated content of palmitic acid.
 ...
PMID:Increased saturated triacylglycerol levels in plasma membranes of human neutrophils stimulated by lipopolysaccharide. 930 Jul 78

Dihomogammalinolenic acid is derived from gammalinolenic acid, administration of which suppresses joint inflammation. It is reported here that interleukin 1beta (IL-1beta) production by human monocytes is enhanced markedly when cells are incubated 18-24 h with the polyunsaturated fatty acids dihomogammalinolenic acid (DGLA) and arachidonic acid (AA), then stimulated with lipopolysaccharide. Effects of eicosapentaenoic acid (EPA) on IL-1beta production are minimal, and palmitic acid (PA) does not influence IL-1beta production.
 ...
PMID:Effects of unsaturated fatty acids on interleukin-1beta production by human monocytes. 941 12

A new class of outer membrane lipid (OML) was isolated from the oral spirochete Treponema denticola strain ATCC 33521 using a phenol/chloroform/light petroleum procedure normally applied for lipopolysaccharide extraction. In addition to chemical analysis, Fourier transform infrared (FTIR) spectroscopy was applied to compare the biophysical properties of OML with lipopolysaccharides (LPS) and lipoteichoic acids (LTA). Isolated OML fractions represent 1.4% of the total dry cell weight, are about 4 kDa in size, and contain 6% amino sugars, 8% neutral sugars, 14% phosphate, 35% carbazol-positive compounds, and 11% fatty acids (containing iso- and anteiso-fatty acyl chains). Rare for outer membrane lipids, OML contains no significant amount of 3-deoxy-D-manno-octulosonic acids, heptoses, and beta-hydroxy fatty acids. The fatty acyl chain composition, being similar to that of the cytoplasmic membrane, is quite heterogeneous with anteiso-pentadecanoic acid (12%), palmitic acid (51%), and iso-palmitic acid (19%) as the predominant fatty acids present. Findings of a glycerol-hexose unit and two glycerol-hexadecanoic acid fragments indicate a glycolipid membrane anchor typically found in LTA. There was also no evidence for the presence of a sphingosine-based lipid structure. The results of FTIR measurements strongly suggest that the reconstituted lipid forms normal bilayer structures (vesicles) expressing a high membrane state of order with a distinct phase transition as typical for isolated LPS. However, in contrast to LPS, OML of T. denticola has a lower Tm near 22 degreesC and a lower cooperativity of the phase transition. The results suggest a different kind of permeation barrier that is built up by this particular OML of T. denticola, which is quite different from LPS normally essential for Gram-negative bacteria.
 ...
PMID:Evidence for a new type of outer membrane lipid in oral spirochete Treponema denticola. Functioning permeation barrier without lipopolysaccharides. 962 60

Human neutrophils incubated for 1 h in vitro with 10% commercial pooled, human serum containing high levels of free fatty acids (1141 microM) displayed a distinct lipid signal, typical of triacylglycerol, in the 1H NMR spectrum. Concurrently their plasma membrane triacylglycerol mass increased 4.6-fold with a selective rise in the content of palmitic and linoleic acids. Although qualitatively similar, these effects were much greater than those observed after incubating neutrophils with 50 microg.mL-1 of lipopolysaccharide in the presence of 10% AB serum with normal free fatty acid content (345 microM, LPS/S). Incubation of neutrophils with an artificial mixture of free fatty acids at concentrations found in commercial serum, or with the fatty acid fraction isolated from commercial serum increased the 1H NMR-detectable triacylglycerol. The signal intensity of the 1H NMR-detectable triacylglycerol depended on the triacylglycerol composition, and correlated with increased membrane triacylglycerol mass. Cellular uptake of 3H-labelled palmitic or oleic acids increased in the presence of commercial serum but not with LPS/S, with little contribution in either case to the triacylglycerol pool that increased in mass. Pulse-chase experiments demonstrated that with LPS/S and commercial serum, radiolabelled palmitic acid was preferentially incorporated into triacylglycerol located in the plasma membrane. This process could occur at the plasma membrane, as cytoplasts efficiently convert exogenous fatty acids into triacylglycerol. We propose that LPS/S and serum containing high levels of free fatty acid, important in conditions of sepsis and inflammation, may facilitate the sequestration of palmitic acid into triacylglycerol by different pathways. This triacylglycerol originates from exogenous and endogenous free fatty acids, is 1H NMR-visible, and may have a role in regulating apoptosis.
 ...
PMID:The origin of 1H NMR-visible triacylglycerol in human neutrophils. Highfatty acid environments result in preferential sequestration of palmitic acid into plasma membrane triacylglycerol. 1060 52

The structure of the lipid A from Rhizobium etli and Rhizobium leguminosarum lipopolysaccharides (LPSs) lacks phosphate and contains a galacturonosyl residue at its 4' position, an acylated 2-aminogluconate in place of the proximal glucosamine, and a very long chain omega-1 hydroxy fatty acid, 27-hydroxyoctacosanoic acid (27OHC28:0). The 27OHC28:0 moiety is common in lipid A's among members of the Rhizobiaceae and also among a number of the facultative intracellular pathogens that form chronic infections, e.g., Brucella abortus, Bartonella henselae, and Legionella pneumophila. In this paper, a mutant of R. leguminosarum was created by placing a kanamycin resistance cassette within acpXL, the gene which encodes the acyl carrier protein for 27OHC28:0. The result was an LPS containing a tetraacylated lipid A lacking 27OHC28:0. A small amount of the mutant lipid A may contain an added palmitic acid residue. The mutant is sensitive to changes in osmolarity and an increase in acidity, growth conditions that likely occur in the nodule microenvironment. In spite of the probably hostile microenvironment of the nodule, the acpXL mutant is still able to form nitrogen-fixing root nodules even though the appearance and development of nodules are delayed. Therefore, it is possible that the acpXL mutant has a host-inducible mechanism which enables it to adapt to these physiological changes.
 ...
PMID:A Rhizobium leguminosarum AcpXL mutant produces lipopolysaccharide lacking 27-hydroxyoctacosanoic acid. 1261 48

Leptospira is the etiologic agent of leptospirosis, a bacterial zoonosis distributed worldwide. Leptospiral lipopolysaccharide is a protective immunogen, but the extensive serological diversity of leptospires has inspired a search for conserved outer membrane proteins (OMPs) that may stimulate heterologous immunity. Previously, a global analysis of leptospiral OMPs (P. A. Cullen, S. J. Cordwell, D. M. Bulach, D. A. Haake, and B. Adler, Infect. Immun. 70:2311-2318, 2002) identified pL21, a novel 21-kDa protein that is the second most abundant constituent of the Leptospira interrogans serovar Lai outer membrane proteome. In this study, we identified the gene encoding pL21 and found it to encode a putative lipoprotein; accordingly, the protein was renamed LipL21. Southern hybridization analysis revealed the presence of lipL21 in all of the pathogenic species but in none of the saprophytic species examined. Alignment of the LipL21 sequence from six strains of Leptospira revealed 96 to 100% identity. When specific polyclonal antisera to recombinant LipL21 were used, LipL21 was isolated together with other known leptospiral OMPs by both Triton X-114 extraction and sucrose density gradient membrane fractionation. All nine strains of pathogenic leptospires investigated by Western blotting, whether culture attenuated or virulent, were found to express LipL21. In contrast, the expression of LipL21 or an antigenically related protein could not be detected in nonpathogenic L. biflexa. Infected hamster sera and two of eight human leptospirosis sera tested were found to react with recombinant LipL21. Native LipL21 was found to incorporate tritiated palmitic acid, consistent with the prediction of a lipoprotein signal peptidase cleavage site. Biotinylation of the leptospiral surface resulted in selective labeling of LipL21 and the previously known OMPs LipL32 and LipL41. These findings show that LipL21 is a surface-exposed, abundant outer membrane lipoprotein that is expressed during infection and conserved among pathogenic Leptospira species.
 ...
PMID:LipL21 is a novel surface-exposed lipoprotein of pathogenic Leptospira species. 1270 11

From Mycobacterium tuberculosis, a serologically specific polysaccharide was purified. It contained mannose, arabinose, and a trace of glucose. It was not active in hemagglutination (HA) reaction. Partial acylation of the polysaccharide was carried out with palmitoylchloride, and the synthetic lipopolysaccharide contained 15.1 per cent of esterified palmitic acid. The synthetic lipopolysaccharide had hemagglutination activity and 0.5 microg was able to sensitize 1 ml of 2 per cent erythrocyte suspension; it had the same activity as the natural antigenic lipopolysaccharide. The same antibody in the antiserum was involved in the hemagglutination reaction with both the synthetic and natural lipopolysaccharides. The sensitizing activity of the synthetic lipopolysaccharide was completely neutralized by cholesterol. Model experiments showed that the lipid moiety of hemagglutination antigen was essential for the sensitization of erythrocytes. The mechanism of the hemagglutination reaction is discussed.
 ...
PMID:A SYNTHETIC ACYL POLYSACCHARIDE AND THE HEMAGGLUTINATION ACTIVITY. 1417 89


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