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

We previously reported that a cytostatic protein that is found in ASC-17D Sertoli cell-conditioned media was Mycoplasma arginine deiminase (ADI), which hydrolyzes L-arginine into L-citrulline and ammonia. Here, we report the over-expression of recombinant ADI (rADI) in E. coli and the down-regulation of lipopolysaccharide (LPS) induced-nitric oxide (NO) production by rADI treatment. We cloned the ADI gene from Mycoplasma arginini genomic DNA by a polymerase chain reaction, and changed five TGA tryptophan codons (stop codon in E. coli) to TGG codons in the coding region by site-directed mutagenesis in order to express in E. coli. The rADI was purified to apparent homogeneity by DEAE-Sepharose and arginine-affinity chromatography. The rADI expressed in E. coli was identified as 45 kDa on SDS-PAGE and 90 kDa on native PAGE, implying that it exists as a dimer like ADI of M. arginini. The Km for arginine of rADI was approximately 370+/-50 microM. Its optimal temperature and pH were 41 degrees C and pH 6.4, respectively, and enzyme activity remained > or = 50% for 5 d at physiological temperature and pH. Treatment of purified rADI suppressed NO production in macrophage-like RAW 264.7 and primary glial cells that were exposed to LPS. Furthermore, an intraperitoneal injection of rADI significantly suppressed the rise of blood nitrite/nitrate levels that were induced by the systemic administration of bacterial endotoxin LPS to mice, resulting in an improvement in their survival rate. These results suggest that the depletion of blood arginine with an arginine-metabolizing enzyme, such as ADI, could suppress excessive production of NO that is caused by inducible NOS (iNOS) during the endotoxemia. Also, rADI may be used as a new approach to control NO-related diseases, such as sepsis.
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PMID:Characterization of mycoplasma arginine deiminase expressed in E. coli and its inhibitory regulation of nitric oxide synthesis. 1191 65

Pentoxifylline, a methylxanthine derivative and nonspecific type 4 phosphodiesterase inhibitor, has been used to improve survival of animals with sepsis and to attenuate lung injury in acute lung inflammation. The purpose of this study was to examine whether pentoxifylline would inhibit the expression of inflammatory cytokines, particularly tumor necrosis factor alpha (TNF), and thereby decrease the pathophysiology of acute porcine pleuropneumonia. E. coli lipopolysaccharide (LPS) and bacterial extracts of A. pleuropneumoniae--induced elevations in TNF mRNA which were fully abrogated by addition of pentoxifylline in both alveolar macrophage and neutrophil cultures. A 30% reduction in the level of LPS-induced interleukin (IL)-1beta mRNA levels also was achieved in macrophages. Pentoxifylline did not affect either IL-1alpha or IL-8 expression in vitro. Pentoxifylline therapy in vivo significantly reduced the number of band neutrophils in swine but did not reduce the pathology associated with pleuropneumonia, including changes in serum zinc, iron, or haptoglobin. Neither did it alter TNF, IL-1, IL-6, or IL-8 expression. Measurement of pentoxifylline and its metabolites in pig sera suggested that efficacious doses of pentoxifylline were probably not achieved in vivo. However, subcutaneous doses of pentoxifylline higher than 25 mg/kg produced transient diarrhea, vomiting, and tremors. These results suggest that pentoxifylline is an effective pharmacological tool for the dissection of cytokine regulation in vitro, but inhibitory concentrations may not be achievable for in vivo pharmacological use in swine.
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PMID:Effects of pentoxifylline on inflammatory cytokine expression and acute pleuropneumonia in swine. 1199 42

Traditionally, adjuvants have been administered with antigens to enhance immunity. We studied the effect of several adjuvants such as Freund's complete adjuvant (FCA), Freund's incomplete adjuvant (FIA), lipopolysaccharide (LPS), homopolymers of polyinosinic-polycytidylic acid (poly I:C) and polyadenylic-polyuridylic acid (poly A:U), lithium chloride (LiCl), saponin Quil A and calcium phosphate gel (CaHPO(4)) on the immune response of mice to formalin-inactivated Mycoplasma agalactiae. The specific antibody or cytokine producing splenocytes were detected by ELISAspot and immunocytochemistry, respectively. Depending on the adjuvant given, the number of M. agalactiae-specific antibody producing cells was increased 2.5-6-fold. IgG was the major class of M. agalactiae-specific antibodies followed by IgM, IgA and IgE. Among IgG isotypes, FCA, FIA, Quil A and CaHPO(4) induced an IgG1 response with substantial increase of the IgG2a, IgG2b and IgG3 isotypes while poly I:C shifted the response toward an IgG2a/IgG3 production. Finally, poly A:U induced an IgG2b response while LPS and LiCl augmented the IgG3/IgG1/IgG2a secretion. FCA augmented IL-4, IL-5 and IL-10 production suggesting a strong Th2 response, while IFN-gamma and IL-12 remained low; poly I:C enhanced IFN-gamma, IL-12 and TNF-alpha eliciting a Th1 response; poly A:U resulted in a IL-10, IL-5, IL-6 and IL-12 secretion; and LPS enhanced the IL-10, IL-6 and TNF-alpha production. Our data show that adjuvants augment M. agalactiae-specific antibody production and lead to B cell isotype-switching via the appropriate cytokine milieu. Certain adjuvants, such as poly I:C, therefore, appear as promising immune enhancers for vaccination against M. agalactiae infections.
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PMID:Adjuvant regulation of cytokine profile and antibody isotype of immune responses to Mycoplasma agalactiae in mice. 1222 Aug 8

The impact of Escherichia coli-derived lipopolysaccharide (LPS) on the pharmacokinetic parameters of enrofloxacin in swine was assessed to determine whether this model would substitute for a pleuropneumonia infection model for pharmacokinetic evaluation of drugs. All animals received a single i.v. dose of enrofloxacin (5 mg/kg). Half the animals also received dexamethasone (0.5 mg/kg) to determine the impact of inflammation on any changes in enrofloxacin pharmacokinetics, as most of the effects of LPS are due to elaboration of inflammatory mediators. Administration of LPS alone (2.0 microg/kg) was associated with a decrease in clearance of enrofloxacin. Volume of distribution at steady state was increased in the dexamethasone-treated animals. The terminal elimination half-life of enrofloxacin was significantly increased in the LPS group. Dexamethasone administration, either alone or in combination with LPS challenge, increased the volume of distribution both at steady state and during the elimination phase. Lipopolysaccharide challenge did not affect the volume of distribution. Lipopolysaccharide challenge did not affect urinary excretion of enrofloxacin but did increase the urinary excretion of its principal metabolite, ciprofloxacin. However, the increased excretion did not begin until 24 h after administration of enrofloxacin. Because these pharamcokinetic results are different from those obtained with the pleuropneumonia model using the bacteria Actinobacillus pleuropneumoniae, the results of this study demonstrate that LPS is not a generic substitute for infection for the pharmacokinetic evaluation of drugs.
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PMID:The effect of endotoxin and dexamethasone on enrofloxacin pharmacokinetic parameters in swine. 1253 47

Serological analysis is often used for the diagnosis of chlamydial infections. However, an increase in Chlamydia antibodies has been reported in patients with parvovirus and Mycoplasma infections. Whether this antibody response is the result of dual infection or nonchlamydial antigen stimulation is unknown. In a randomized study, 48 healthy volunteers either were immunized against yellow fever, polio, diphtheria, and tetanus (the group receiving intervention with nonchlamydial antigen) or received saline injections (the placebo group). The change in antibody levels was compared between the 2 groups. The Chlamydia recombinant lipopolysaccharide enzyme-linked immunosorbent assay (Medac) showed an increase in the antibody titer in the intervention group, compared with that in the control group (for immunoglobulin M, P=.004; for immunoglobulin A, P=.038; and for immunoglobulin G, P=.056), but no differences between study groups was found when the C. pneumoniae enzyme immunoassay (EIA; ThermoLabsystems), the C. pneumoniae EIA (Medac), and the microimmunofluorescence test (MRL) were used. An increase in antibodies to Chlamydia organisms can be measured after exposure to nonchlamydial antigens, depending on the test used.
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PMID:Chlamydia antibody response in healthy volunteers immunized with nonchlamydial antigens: a randomized, double-blind, placebo-controlled study. 1259 39

Mycoplasma arthritidis causes arthritis in rodents that resembles human rheumatoid arthritis. It produces a superantigen (MAM) that stimulates production of cytokines by making a bridge between lymphocyte T-cell receptor with the appropriate Vbeta chain, and H-2 1-Ealpha MHC class II molecules. Here we studied MAM-induced nitric oxide (NO) production in mouse peritoneal macrophages and found that it was: (1) time and concentration dependent, (2) possibly derived from inducible NOS synthase since it was reduced significantly by amino guanidine pretreatment, (3) restricted to H-2(K) (C3H/HePas and C3H/HeJ) and H-2(d) strains (BALB/c), (4) independent of TLR4 signaling since the coisogenic strains C3H/HePas and C3H/HeJ (TLR4 deficient) produced similar levels of NO following MAM stimulation, (5) potentiated by lipopolysaccharide, and (6) dependent on the presence of nonadherent peritoneal cells. Neutralization of interferon-gamma (IFNgamma in the peritoneal cell cultures with monoclonal antibodies abolished MAM-induced NO production. Addition of rIFNgamma to the adherent cells substituted the nonadherent cells for MAM-induced NO production. A macrophage cell line, J774A.1 (H-2(d)), also produced NO upon MAM stimulation but only when BALB/c spleen lymphocytes were added. Thus, in murine macrophages, MAM induces NO production that is dependent on signaling through MHC class II molecules and IFNgamma but independent of TLR4 expression.
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PMID:Mycoplasma arthritidis superantigen (MAM)-induced macrophage nitric oxide release is MHC class II restricted, interferongamma dependent, and toll-like receptor 4 independent. 1274 62

Dendritic cells (DC) modulate immune responses depending on the nature of the antigens. Receptors capable of discriminating these antigens on the basis of the pathogen-associated molecular patterns (PAMP) belong to the Toll-like receptor (TLR) family. The macrophage-activating lipopeptide 2 kDa (MALP-2), a synthetic lipopeptide derived from Mycoplasma fermentans, signals through TLR-2 and TLR-6. The aim of this study was to examine whether MALP-2 can modulate the functional properties of human monocyte-derived DC. The effects of this treatment were compared to those of the TLR-4 agonist lipopolysaccharide (LPS). To ensure clinical applicability, DC were generated under serum-free conditions. MALP-2 and LPS stimulation induced the expression of CD83 and increased the expressions of CD80, CD86, HLA-ABC and CD40. Furthermore, both substances decreased the endocytotic capacity of DC and induced the release of bioactive TNF-alpha and IL-10, whereas LPS additionally increased IL-12 release. Pretreatment with both substances boosted the allostimulatory capacity of DC. In a coculture with autologous lymphocytes, either MALP-2 or LPS pretreated DC induced a marked proliferation of lymphocytes, but only DC prestimulated with MALP-2 activated lymphocytes to produce the cytokines IL-4, IL-5 and IFN-gamma. No polarisation of lymphocytes into T-helper (Th)1 or Th2 was detected. These data indicate that MALP-2 is a potential candidate to modulate DC for clinical applications.
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PMID:Synthetic mycoplasma-derived lipopeptide MALP-2 induces maturation and function of dendritic cells. 1277 64

Actinobacillus pleuropneumoniae is a strict respiratory tract pathogen of swine and is the causative agent of porcine pleuropneumonia. We have used signature-tagged mutagenesis (STM) to identify genes required for survival of the organism within the pig. A total of 2,064 signature-tagged Tn10 transposon mutants were assembled into pools of 48 each, and used to inoculate pigs by the endotracheal route. Out of 105 mutants that were consistently attenuated in vivo, only 11 mutants showed a >2-fold reduction in growth in vitro compared to the wild type, whereas 8 of 14 mutants tested showed significant levels of attenuation in pig as evidenced from competitive index experiments. Inverse PCR was used to generate DNA sequence of the chromosomal domains flanking each transposon insertion. Only one sibling pair of mutants was identified, but three apparent transposon insertion hot spots were found--an anticipated consequence of the use of a Tn10-based system. Transposon insertions were found within 55 different loci, and similarity (BLAST) searching identified possible analogues or homologues for all but four of these. Matches included proteins putatively involved in metabolism and transport of various nutrients or unknown substances, in stress responses, in gene regulation, and in the production of cell surface components. Ten of the sequences have homology with genes involved in lipopolysaccharide and capsule production. The results highlight the importance of genes involved in energy metabolism, nutrient uptake and stress responses for the survival of A. pleuropneumoniae in its natural host: the pig.
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PMID:Identification of Actinobacillus pleuropneumoniae genes important for survival during infection in its natural host. 1281 83

We report a comprehensive physicochemical characterization of a glycoglycerolipid from Mycoplasma fermentans, MfGl-II, in relation to its bioactivity and compared this with the respective behaviors of phosphatidylcholine (PC) and a bacterial glycolipid, lipopolysaccharide (LPS) from deep rough mutant Salmonella minnesota strain R595. The beta left arrow over right arrow alpha gel-to-liquid crystalline phase transition behavior of the hydrocarbon chains with Tc = 30 degrees C for MfGl-II as well as for LPS exhibits high similarity between the two glycolipids. A lipopolysaccharide-binding protein (LBP)-mediated incorporation into negatively charged liposomes is observed for both glycolipids. The determination of the supramolecular aggregate structure confirms the existence of a mixed unilamellar/cubic structure for MfGl-II, similar to that observed for the lipid A moiety of LPS. The biological data clearly show that MfGl-II is able to induce cytokines such as tumor necrosis factor-alpha (TNF-alpha) in human mononuclear cells, although to a significantly lower degree than LPS. In contrast, in the Limulus amebocyte lysate test, MfGl-II is completely inactive, and in the CHO reporter cell line it does not indicate any reactivity with the Toll-like receptors TLR-2 and -4, in contrast to control lipopeptides and LPS. These data confirm the applicability of our conformational concept of endotoxicity to nonlipid A structures: an amphiphilic molecule with a nonlamellar cubic aggregate structure corresponding to a conical conformation of the single molecules and a sufficiently high negative charge density in the backbone.
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PMID:Physicochemical characterization and biological activity of a glycoglycerolipid from Mycoplasma fermentans. 1286 3

The gram-negative bacterium Actinobacillus pleuropneumoniae is the causative agent of porcine fibrinohemorrhagic necrotizing pleuropneumonia, a disease that causes important economic losses to the swine industry worldwide. In general, the initial step of bacterial colonization is attachment to host cells. The purpose of the present study was to evaluate the binding of A. pleuropneumoniae serotype 1 to phospholipids, which are the major constituents of biological membranes. Phospholipids serve as receptors for several bacteria, including respiratory pathogens. To study this effect, we used thin-layer chromatography overlay binding assays to test commercial phospholipids such as phosphatidic acid, phosphatidylcholine, phosphatidylserine, phosphatidylinositol, phosphatidylglycerol, and phosphatidylethanolamine (PE). Our results indicate that A. pleuropneumoniae serotype 1 binds to PE but not to the other phospholipids tested. Serotypes 5b and 7, which, along with serotype 1, are the most prevalent serotypes of A. pleuropneumoniae in North America, share the ability to bind PE. Inhibition of binding with a monoclonal antibody against A. pleuropneumoniae serotype 1 O antigen and the use of isogenic lipopolysaccharide (LPS) mutants of A. pleuropneumoniae serotype 1 showed that the O antigen seems to be implicated in the binding to PE, at least for A. pleuropneumoniae serotype 1. A. pleuropneumoniae was also shown to bind to a phospholipid extracted from swine lungs by using the method of Folch. Chemical staining with molybdenum blue and ninhydrin, migration with neutral, acidic, and basic solvent systems, and mass spectrometry analysis all indicated that this lipid is PE. This study is, to the best of our knowledge, the first description of A. pleuropneumoniae binding to phospholipids. Our data also suggest that LPS O antigens could be involved in binding to PE.
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PMID:Binding of Actinobacillus pleuropneumoniae to phosphatidylethanolamine. 1287 46


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