These are representative sample records from related to your search topic.
For comprehensive and current results, perform a real-time search at

Endotoxin-free protein production--ClearColiTM A new Escherichia coli strain with a genetically modified lipopolysaccharide (LPS) molecule has been  

E-print Network

and cytokine assays. Introduction ClearColiTM competent cell strains are derivatives of E. coli, which-approved biologics. One of the major limitations in using traditional E. coli strains relates to the LPS component. Genetically eliminating LPS from the E. coli outer membrane is technically a more efficient means to prepare

Cai, Long


Influence of endotoxin-protein in immunoglobulin G isotype responses of mice to Brucella abortus lipopolysaccharide.  

PubMed Central

Brucella abortus endotoxin preparations, containing approximately 5 to 6% protein, induce strong immune and adjuvant immunoglobulin G (IgG) responses as compared with Escherichia coli endotoxin preparations, with equivalent amounts of protein, which induce responses in which IgM antibody predominates. Using an enzyme-linked immunoassay with isotype-specific conjugates, we found that antibody of all four subclasses of IgG were evoked during the course of the immune responses of C3H/HeAu mice to B. abortus endotoxin. Secondary responses of endotoxin-hyporesponsive C3H/HeJ mice were similar to those seen in C3H/HeAu mice, although lower levels of antibody were produced during their primary responses. The primary responses of BALB/c athymic mice consisted almost entirely of IgG3, and IgG1 appeared following a second injection. The effects of lipopolysaccharide (LPS)-associated protein on the immunogenic properties of B. abortus endotoxin were examined by comparing responses to endotoxin with those to a purified B. abortus LPS containing less than 1% protein. The endotoxin evoked strong primary and secondary responses in which antibody directed to LPS determinants consisted mainly of IgG3 and those to the protein determinants were largely IgG1 antibody. Primary and secondary responses to purified LPS consisted mainly of IgG3 antibody. The potential mechanism of the contribution of protein to the immunogenic properties of the endotoxin as well as possible immune mechanisms involved in these responses are discussed. PMID:3096890

Kurtz, R S; Berman, D T



Properties of binding of Escherichia coli endotoxin to various matrices.  


Binding of Escherichia coli O127:B8 endotoxin to a variety of resins and column materials was investigated by measuring the beta-hydroxy myristic acid content (a major component of the lipid A moiety) of endotoxin after hydrolysis by selected ion-monitoring gas chromatography-mass spectrometry. More than 80% of the endotoxin was bound to hydroxylapatite, polystyrene, Dowex 1-X2, and charcoal. The binding of endotoxin to these materials was markedly reduced by the addition of normal or delipidated serum. Phenyl- and octyl-Sepharose bound 56 and 50% of the endotoxin from saline solutions, respectively. Their percent binding was increased significantly in 1 M ammonium sulfate solutions, indicating hydrophobic interactions between endotoxin and phenyl- and octyl-Sepharose. Only 5% of the endotoxin was bound to plastic polymer PSI-HAP-100 beads, and no binding was observed with concanavalin A- and heparin-Sepharose. Study of the in vitro binding of endotoxin to the above material in the presence of serum suggests that the use of these materials in removing circulating endotoxin in vivo is limited. PMID:7007429

Maitra, S K; Yoshikawa, T T; Guze, L B; Schotz, M C



Inactivation of Escherichia coli Endotoxin by Soft Hydrothermal Processing?  

PubMed Central

Bacterial endotoxins, also known as lipopolysaccharides, are a fever-producing by-product of gram-negative bacteria commonly known as pyrogens. It is essential to remove endotoxins from parenteral preparations since they have multiple injurious biological activities. Because of their strong heat resistance (e.g., requiring dry-heat sterilization at 250°C for 30 min) and the formation of various supramolecular aggregates, depyrogenation is more difficult than sterilization. We report here that soft hydrothermal processing, which has many advantages in safety and cost efficiency, is sufficient to assure complete depyrogenation by the inactivation of endotoxins. The endotoxin concentration in a sample was measured by using a chromogenic limulus method with an endotoxin-specific limulus reagent. The endotoxin concentration was calculated from a standard curve obtained using a serial dilution of a standard solution. We show that endotoxins were completely inactivated by soft hydrothermal processing at 130°C for 60 min or at 140°C for 30 min in the presence of a high steam saturation ratio or with a flow system. Moreover, it is easy to remove endotoxins from water by soft hydrothermal processing similarly at 130°C for 60 min or at 140°C for 30 min, without any requirement for ultrafiltration, nonselective adsorption with a hydrophobic adsorbent, or an anion exchanger. These findings indicate that soft hydrothermal processing, applied in the presence of a high steam saturation ratio or with a flow system, can inactivate endotoxins and may be useful for the depyrogenation of parenterals, including end products and medical devices that cannot be exposed to the high temperatures of dry heat treatments. PMID:19502435

Miyamoto, Toru; Okano, Shinya; Kasai, Noriyuki



Clindamycin Suppresses Endotoxin Released by Ceftazidime-Treated Escherichia coli O55:B5 and Subsequent Production of Tumor Necrosis Factor Alpha and Interleukin-1?  

PubMed Central

Treatment of septicemia caused by Escherichia coli with ceftazidime (CAZ) may be associated with the development of septic shock due to the release of bacterial lipopolysaccharide. We examined the suppressive effect of clindamycin (CLDM) on CAZ-induced release of endotoxin by cultured E. coli and the subsequent production of inflammatory cytokines (tumor necrosis factor alpha [TNF-?] and interleukin-1? [IL-1?]). E. coli ATCC 12014 was incubated in inactivated horse serum with or without CLDM for 1, 4, or 18 h, followed by the addition of CAZ and collection of the culture supernatant at 0, 1, and 2 h. The concentration of endotoxin in each sample was measured by a chromogenic Limulus test. Another portion of the culture supernatant was added to THP-1 cell culture and incubated for 4 h, and the concentrations of TNF-? and IL-1? in the supernatant were measured by an enzyme-linked immunosorbent assay. In the control group (no CLDM), CAZ administration resulted in significant increases in endotoxin, TNF-?, and IL-1? concentrations. Pretreatment of E. coli with CLDM for 4 or 18 h before the addition of CAZ significantly suppressed the concentrations of endotoxin, TNF-?, and IL-1? in a time-dependent manner. In addition, CAZ treatment transformed E. coli from rod-shaped bacteria to filament-like structures, as determined by electron microscopy, while pretreatment with CLDM prevented these morphological changes. Our in vitro studies showed that CAZ-induced release of large quantities of endotoxin by E. coli could be suppressed by prior administration of CLDM. PMID:10049276

Kishi, Kenji; Hirai, Kazuhiro; Hiramatsu, Kazufumi; Yamasaki, Tohru; Nasu, Masaru



Original article Local and systemic effects of endotoxin mastitis  

E-print Network

Original article Local and systemic effects of endotoxin mastitis on the chemiluminescence of milk ­ The local and systemic effects of intramammary lipopolysaccharide (LPS) injection on the chemiluminescence of E. coli endotoxin is involved in the priming of milk PMN during mastitis. chemiluminescence

Paris-Sud XI, Université de


Anti-Endotoxin Agents. 2. Pilot High-Throughput Screening for Novel Lipopolysaccharide-Recognizing Motifs in Small Molecules  

PubMed Central

Lipopolysaccharides (LPS), otherwise termed ‘endotoxins’, are an integral part of the outer leaflet of the outer-membrane of Gram-negative bacteria. Lipopolysaccharides play a pivotal role in the pathogenesis of ‘Septic Shock’, a major cause of mortality in the critically ill patient, worldwide. The sequestration of circulatory endotoxin may be a viable therapeutic strategy for the prophylaxis and treatment of Gram-negative sepsis. We have earlier shown that the pharmacophore necessary for small molecules to bind LPS is simple, comprising of two protonatable cationic functions separated by about 15Ĺ, permitting the simultaneous interaction with the negatively charged phosphates on lipid A, the toxically active center of endotoxin. In this report, we employ high-throughput screening methods, using a novel fluorescent probe displacement method. Searches in three-dimensional structure databases yielded about ~ 4000 commercially available small molecules, each possessing two cationic functions spaced approximately 15Ĺ apart. Approximately 400 such compounds have been screened in an effort to validate the method by which high-affinity endotoxin binders can be identified. We show that the IC50 values that are obtained from the fluorescence-based primary screen are correlated both to the enthalpy of binding, as measured by isothermal titration calorimetry, as well as to biological potency in vitro assays. By performing rapid toxicity screens in tandem with the bioassays, lead compounds of interest can be easily identified for further systematic structural modifications and SAR studies. PMID:15578935

Wood, Stewart J.; Miller, Kelly A.; David, Sunil A.



Capture of Lipopolysaccharide (Endotoxin) by the Blood Clot: A Comparative Study  

PubMed Central

In vertebrates and arthropods, blood clotting involves the establishment of a plug of aggregated thrombocytes (the cellular clot) and an extracellular fibrillar clot formed by the polymerization of the structural protein of the clot, which is fibrin in mammals, plasma lipoprotein in crustaceans, and coagulin in the horseshoe crab, Limulus polyphemus. Both elements of the clot function to staunch bleeding. Additionally, the extracellular clot functions as an agent of the innate immune system by providing a passive anti-microbial barrier and microbial entrapment device, which functions directly at the site of wounds to the integument. Here we show that, in addition to these passive functions in immunity, the plasma lipoprotein clot of lobster, the coagulin clot of Limulus, and both the platelet thrombus and the fibrin clot of mammals (human, mouse) operate to capture lipopolysaccharide (LPS, endotoxin). The lipid A core of LPS is the principal agent of gram-negative septicemia, which is responsible for more than 100,000 human deaths annually in the United States and is similarly toxic to arthropods. Quantification using the Limulus Amebocyte Lysate (LAL) test shows that clots capture significant quantities of LPS and fluorescent-labeled LPS can be seen by microscopy to decorate the clot fibrils. Thrombi generated in the living mouse accumulate LPS in vivo. It is suggested that capture of LPS released from gram-negative bacteria entrapped by the blood clot operates to protect against the disease that might be caused by its systemic dispersal. PMID:24282521

Armstrong, Margaret T.; Rickles, Frederick R.; Armstrong, Peter B.



Effects of endotoxin on mammary secretion of lactating cows. [Escherichia coli  

SciTech Connect

The objectives were to describe the magnitude and time course of changes in milk pH, Na, K, lactose, and somatic cells and to determine if paracellular pathways were altered after infusion of Escherichia coli endotoxin (serotype 0128:AB12) to produce inflammation in one-half of the udder of the goat. Intramammary infusion of endotoxin increased pH, number of somatic cells, and Na and decreased K and lactose in milk. Sodium and number of somatic cells were increased by as little as of endotoxin; .25 produced changes in most of the other parameters; maximal effect was elicited by of endotoxin. The gland response peaked from 5 to 7 h after infusion of endotoxin with an increase in milk cellularity as the only significant effect noted in the control gland. Infusion of (/sup 14/C)lactose into the gland and (/sup 99m/Tc)albumin into the blood demonstrated that large molecules were more able to cross into and out of udder halves after endotoxin treatment. It is suggested that ion interchange rather than bulk flow across paracellular paths is responsible for changes. In addition, endotoxin appeared to reduce lactose secretion and synthesis.

Lengemann, F.W.; Pitzrick, M.



Lpsd/Ran of endotoxin-resistant C3H/HeJ mice is defective in mediating lipopolysaccharide endotoxin responses  

PubMed Central

C3H/HeJ inbred mice are defective in that they are highly resistant to endotoxic shock as compared with normal responder mice. Their B cells and macrophages do not respond significantly when exposed to lipopolysaccharide (LPS), whereas cells from the responder mice do. Using a functional assay, we previously isolated a cDNA, which encodes for Ran/TC4 GTPase. We now show that this gene is mutated in C3H/HeJ mice, which accounts for their resistance to endotoxin stimulation. Sequence analysis of independent mutant Lpsd/Ran cDNAs isolated from splenic B cells of C3H/HeJ mice reveals a consistent single base substitution at position 870, where a thymidine is replaced with a cytidine. In situ hybridization maps the Lpsd/Ran cDNA to mouse chromosome 4. By retroviral gene transfer, the wild-type Lpsn/Ran cDNA but not the mutant Lpsd/Ran cDNA can restore LPS responsiveness of C3H/HeJ cells. Adenoviral gene transfer in vivo with the mutant Lpsd/Ran cDNA but not the wild-type Lpsn/Ran cDNA rescues endotoxin-sensitive mice from septic shock. Thus Lps/Ran is an important target for LPS-mediated signal transduction, and the Lpsd/Ran gene may be useful as a therapeutic sequence in gene therapy for endotoxemia and septic shock. PMID:10500213

Wong, Peter M. C.; Kang, Anthony; Chen, Hong; Yuan, Quan; Fan, Peidong; Sultzer, Barnet M.; Kan, Yuet Wai; Chung, Siu-Wah



Trametinib, a novel MEK kinase inhibitor, suppresses lipopolysaccharide-induced tumor necrosis factor (TNF)-? production and endotoxin shock.  


Lipopolysaccharide (LPS), one of the most prominent pathogen-associated molecular patterns (PAMPs), activates macrophages, causing release of toxic cytokines (i.e. tumor necrosis factor (TNF)-?) that may provoke inflammation and endotoxin shock. Here, we tested the potential role of trametinib, a novel and highly potent MAPK/ERK kinase (MEK) inhibitor, against LPS-induced TNF-? response in monocytes, and analyzed the underlying mechanisms. We showed that trametinib, at nM concentrations, dramatically inhibited LPS-induced TNF-? mRNA expression and protein secretion in transformed (RAW 264.7 cells) and primary murine macrophages. In ex-vivo cultured human peripheral blood mononuclear cells (PBMCs), this MEK inhibitor similarly suppressed TNF-? production by LPS. For the mechanism study, we found that trametinib blocked LPS-induced MEK-ERK activation in above monocytes, which accounted for the defective TNF-? response. Macrophages or PBMCs treated with a traditional MEK inhibitor PD98059 or infected with MEK1/2-shRNA lentivirus exhibited a similar defect as trametinib, and nullified the activity of trametinib. On the other hand, introducing a constitutively-active (CA) ERK1 restored TNF-? production by LPS in the presence of trametinib. In vivo, mice administrated with trametinib produced low levels of TNF-? after LPS stimulation, and these mice were protected from LPS-induced endotoxin shock. Together, these results show that trametinib inhibits LPS-induced TNF-? expression and endotoxin shock probably through blocking MEK-ERK signaling. PMID:25684183

Shi-Lin, Du; Yuan, Xue; Zhan, Sun; Luo-Jia, Tang; Chao-Yang, Tong



Inability of the Francisella tularensis lipopolysaccharide to mimic or to antagonize the induction of cell activation by endotoxins.  

PubMed Central

We studied the ability of the lipopolysaccharide (LPS) extracted from a vaccine strain of Francisella tularensis (LPS-Ft) to mimic LPSs from other gram-negative bacteria for activation of various murine cell types or to antagonize the effects of other LPSs. We found that activation of macrophages for the production of tumor necrosis factor alpha and NO, of pre-B lymphocytes for the expression of surface immunoglobulins, and of bone marrow cells for the expression of LPS-binding sites was either undetectable with LPS-Ft or required concentrations 100 to 1,000 times higher than for standard LPSs. Preexposure of macrophages to LPS-Ft also failed to trigger down-regulation of tumor necrosis factor alpha (desensitization) or up-regulation of NO responses to an endotoxin challenge. In contrast to other atypical LPSs, LPS-Ft was also unable to antagonize any of the endotoxin-induced cellular responses mentioned above, suggesting that this LPS does not interact with LPS receptors. PMID:8675305

Ancuta, P; Pedron, T; Girard, R; Sandström, G; Chaby, R



The third component of complement protects against Escherichia coli endotoxin-induced shock and multiple organ failure  

PubMed Central

We investigated whether the third component of complement (C3) is involved in the pathophysiology of endotoxic shock, and if it is involved, whether it plays a protective role or whether it mediates shock and multiple organ failure. In a prospective, controlled investigation, six Brittany spaniels that were homozygous for a genetically determined deficiency of C3 (C3 deficient, < 0.003% of normal serum C3 levels) and six heterozygous littermates (controls, approximately 50% of mean normal serum C3 level) were given 2 mg/kg of reconstituted Escherichia coli 026:B6 acetone powder as a source of endotoxin, intravenously. All animals were given similar fluid and prophylactic antibiotic therapy, and had serial hemodynamic variables obtained. After E. coli endotoxin infusion, C3-deficient animals had higher peak levels of endotoxin and less of a rise in temperature than controls (P < 0.05). During the first 4 h after E. coli endotoxin infusion, C3-deficient animals had significantly greater decreases in mean central venous pressure and mean pulmonary artery pressure than controls (P < 0.02). During the first 48 h after E. coli endotoxin infusion, C3-deficient animals had significantly greater decreases in mean arterial pH, left ventricular ejection fraction, and mean pulmonary capillary wedge pressure, and greater increases in mean arterial lactate, arterial-alveolar O2 gradient, and transaminases (aspartate aminotransferase and alanine aminotransferase) than controls, (all P < 0.05). After E. coli endotoxin infusion, C3- deficient animals compared to controls had significantly less of a decrease in mean C5 levels (P < 0.01), but similar (P = NS) increases in circulating tumor necrosis factor levels, bronchoalveolar lavage neutrophils, and protein, and similar (P = NS) decreases in blood leukocytes and platelets. Two of six C3-deficient animals and two of six controls died. In summary, after intravenous infusion of E. coli endotoxin, canines with C3 deficiency have decreased endotoxin clearance and worse E. coli endotoxin-induced shock and organ damage. Thus, the third component of the complement system plays a beneficial role in the host defense against E. coli endotoxic shock. PMID:8294868



Escherichia coli lipopolysaccharide administration transiently suppresses luteal structure and function in diestrous cows.  


The objective was to characterize the effects of Escherichia coli lipopolysaccharide (LPS) endotoxin (given i.v.) on luteal structure and function. Seven nonlactating German Holstein cows, 5.1 ± 0.8 years old (mean ± s.e.m.), were given 10? ml saline on day 10 (ovulation=day 1) of a control estrous cycle. On day 10 of a subsequent cycle, they were given 0.5 ?g/kg LPS. Luteal size decreased (from 5.2 to 3.8 cm˛, P?0.05) within 24 h after LPS treatment and remained smaller throughout the remainder of the cycle. Luteal blood flow decreased by 34% (P?0.05) within 3 h after LPS and remained lower for 72 h. Plasma progesterone (P?) concentrations increased (P?0.05) within the first 3 h after LPS but subsequently declined. Following LPS treatment, plasma prostaglandin (PG) F metabolites concentrations were approximately tenfold higher in LPS-treated compared with control cows (9.2 vs 0.8 ng/ml, P?0.05) within 30 min, whereas plasma PGE concentrations were nearly double (P?0.05) at 1 h after LPS. At 12 h after treatment, levels of mRNA encoding Caspase-3 in biopsies of the corpus luteum (CL) were increased (P?0.05), whereas those encoding StAR were decreased (P?0.05) in cattle given LPS vs saline. The CASP3 protein was localized in the cytoplasm and/or nuclei of luteal cells, whereas StAR was detected in the cytosol of luteal cells. In the estrous cycle following treatment with either saline or LPS, there were no significant differences between groups on luteal size, plasma P? concentrations, or gene expression. In conclusion, LPS treatment of diestrus cows transiently suppressed both the structure and function of the CL. PMID:22829687

Herzog, K; Strüve, K; Kastelic, J P; Piechotta, M; Ulbrich, S E; Pfarrer, C; Shirasuna, K; Shimizu, T; Miyamoto, A; Bollwein, H



Comparison of bacterial endotoxin lipopolysaccharide concentrations in the blood, ovarian follicular fluid and uterine fluid: a clinical case of bovine metritis  

PubMed Central

We investigated the concentration of the bacterial endotoxin lipopolysaccharide (LPS) in the blood, ovarian follicular fluid and uterine fluid of a clinical case of bovine metritis. A 2-year-old lactating Holstein cow exhibited continuous fever >39.5°C for more than 2 weeks after normal calving. The cow produced a fetid, watery, red-brown uterine discharge from the vagina and was diagnosed with metritis. The LPS concentrations in plasma and uterine fluid were 0.94 and 6.34 endotoxin units (EU)/ml, respectively. One of seven follicles showed an extremely high level of LPS (12.40 EU/ml) compared to the other follicles (0.62–0.97 EU/ml). These results might suggest the presence of high concentration of LPS in follicles in cows with postpartum metritis. PMID:25223344

MAGATA, Fumie; ISHIDA, Yoshikazu; MIYAMOTO, Akio; FURUOKA, Hidefumi; INOKUMA, Hisashi; SHIMIZU, Takashi



Comparison of bacterial endotoxin lipopolysaccharide concentrations in the blood, ovarian follicular fluid and uterine fluid: a clinical case of bovine metritis.  


We investigated the concentration of the bacterial endotoxin lipopolysaccharide (LPS) in the blood, ovarian follicular fluid and uterine fluid of a clinical case of bovine metritis. A 2-year-old lactating Holstein cow exhibited continuous fever >39.5°C for more than 2 weeks after normal calving. The cow produced a fetid, watery, red-brown uterine discharge from the vagina and was diagnosed with metritis. The LPS concentrations in plasma and uterine fluid were 0.94 and 6.34 endotoxin units (EU)/ml, respectively. One of seven follicles showed an extremely high level of LPS (12.40 EU/ml) compared to the other follicles (0.62-0.97 EU/ml). These results might suggest the presence of high concentration of LPS in follicles in cows with postpartum metritis. PMID:25223344

Magata, Fumie; Ishida, Yoshikazu; Miyamoto, Akio; Furuoka, Hidefumi; Inokuma, Hisashi; Shimizu, Takashi



Acute inflammatory effects of intratracheally instilled Escherichia coli endotoxin and sonicated suspension of Haemophilus pleuropneumoniae in swine.  

PubMed Central

A single bolus of either Escherichia coli endotoxin, sonicated suspension of Haemophilus pleuropneumoniae, or pyrogen-free normal saline was intratracheally instilled in six week old specific-pathogen-free pigs. Pigs exposed to E. coli endotoxin developed fever, leukopenia followed by leukocytosis, and endotoxemia. Leukocytosis was the only clinical abnormality noted in pigs receiving the sonicated suspension of H. pleuropneumoniae. At one day postexposure, focal areas of atelectasis and consolidation were observed in the caudal lung lobes of animals receiving either E. coli endotoxin or the sonicated suspension of H. pleuropneumoniae. Lesions were characterized by a neutrophilic bronchitis and bronchiolitis with alveolitis in the surrounding tissue. Increased numbers of alveolar macrophages and evidence of phagocytosis were observed by light and electron microscopy. No clinical abnormalities or lesions were observed in animals receiving normal saline. Lesions typical of acute porcine Haemophilus pleuropneumonia were not produced by either E. coli endotoxin or sonicated suspension of H. pleuropneumoniae, indicating that multiple virulence factors are probably involved in lesion development. Images Fig. 1. Fig. 2. Fig. 3. PMID:3539296

Liggett, A D; Harrison, L R; Farrell, R L



Low Endotoxin Release from Escherichia coli and Bacteroides fragilis during Exposure to Moxifloxacin  

Microsoft Academic Search

Background: Bacterial endotoxin is known to act as a potent trigger of disseminated coagulation and septic shock. During clinical antibiotic treatment, endotoxin may be released from Gram-negative bacteria. It is known that antibiotic classes differ in their ability to induce endotoxin release. Aim: It was the aim of this study to test the endotoxin-liberating potential of different antibiotics with activity

Matthias Trautmann; Cordula Scheibe; Nele Wellinghausen; Otto Holst; Philipp M. Lepper



PmrD Is Required for Modifications to Escherichia coli Endotoxin That Promote Antimicrobial Resistance.  


In Salmonella enterica, PmrD is a connector protein that links the two-component systems PhoP-PhoQ and PmrA-PmrB. While Escherichia coli encodes a PmrD homolog, it is thought to be incapable of connecting PhoPQ and PmrAB in this organism due to functional divergence from the S. enterica protein. However, our laboratory previously observed that low concentrations of Mg(2+), a PhoPQ-activating signal, leads to the induction of PmrAB-dependent lipid A modifications in wild-type E. coli (C. M. Herrera, J. V. Hankins, and M. S. Trent, Mol Microbiol 76:1444-1460, 2010, These modifications include phosphoethanolamine (pEtN) and 4-amino-4-deoxy-l-arabinose (l-Ara4N), which promote bacterial resistance to cationic antimicrobial peptides (CAMPs) when affixed to lipid A. Here, we demonstrate that pmrD is required for modification of the lipid A domain of E. coli lipopolysaccharide (LPS) under low-Mg(2+) growth conditions. Further, RNA sequencing shows that E. coli pmrD influences the expression of pmrA and its downstream targets, including genes coding for the modification enzymes that transfer pEtN and l-Ara4N to the lipid A molecule. In line with these findings, a pmrD mutant is dramatically impaired in survival compared with the wild-type strain when exposed to the CAMP polymyxin B. Notably, we also reveal the presence of an unknown factor or system capable of activating pmrD to promote lipid A modification in the absence of the PhoPQ system. These results illuminate a more complex network of protein interactions surrounding activation of PhoPQ and PmrAB in E. coli than previously understood. PMID:25605366

Rubin, Erica J; Herrera, Carmen M; Crofts, Alexander A; Trent, M Stephen



SoxRS-Mediated Lipopolysaccharide Modification Enhances Resistance against Multiple Drugs in Escherichia coli  

Microsoft Academic Search

Lipopolysaccharide (LPS) is a major constituent of the outer membrane of gram-negative bacteria that serves as a barrier against harmful molecules, including antibiotics. The waaYZ locus that encodes the LPS core biosynthetic function in Escherichia coli was found to be induced strongly by superoxide generators but not by H2O2, ethanol, or heat shock. This induction was dependent on SoxRS, a

Joon-Hee Lee; Kang-Lok Lee; Won-Sik Yeo; Su-Jin Park; Jung-Hye Roe



Adhesion-promoting receptors on human macrophages recognize Escherichia coli by binding to lipopolysaccharide  

PubMed Central

We report here that human macrophages bind Escherichia coli by recognizing bacterial lipopolysaccharide (LPS). Purified LPS was inserted into erythrocyte membranes, and the resulting LPS-coated red cells were bound by macrophages with the same temperature and cation dependence as observed for E. coli. When receptors for LPS were withdrawn from the plasma membrane by spreading the macrophages on LPS- coated surfaces, the binding of E. coli was blocked. We have also identified the receptors on macrophages that recognize LPS. Macrophages express three structurally homologous cell surface proteins, CR3, lymphocyte function-associated antigen (LFA-1), and p150,95. We used surface-bound monoclonal antireceptor antibodies to selectively remove these proteins from the apical surface of macrophages. We found that each of these proteins mediated the binding of E. coli to macrophages. PMID:3537192



Kdo2Lipid A of Escherichia coli, a defined endotoxin that activates macrophages via TLR-4  

Microsoft Academic Search

The LIPID MAPS Consortium (www.lipidmaps. org) is developing comprehensive procedures for identify- ing all lipids of the macrophage, following activation by endotoxin. The goal is to quantify temporal and spatial changes in lipids that occur with cellular metabolism and to develop bioinformatic approaches that establish dynamic lipid networks. To achieve these aims, an endotoxin of the highest possible analytical specification

Christian R. H. Raetz; Teresa A. Garrett; C. Michael Reynolds; Walter A. Shaw; Jeff D. Moore; Dale C. Smith; Anthony A. Ribeiro; Robert C. Murphy; Richard J. Ulevitch; Colleen Fearns; Donna Reichart; Christopher K. Glass; Chris Benner; Shankar Subramaniam; Richard Harkewicz; Rebecca C. Bowers-Gentry; Matthew W. Buczynski; Jennifer A. Cooper; Raymond A. Deems; Edward A. Dennis



Mammalian nitrate biosynthesis: mouse macrophages produce nitrite and nitrate in response to Escherichia coli lipopolysaccharide  

Microsoft Academic Search

Escherichia coli lipopolysaccharide (LPS)-induced nitrate biosynthesis was studied in LPS-sensitive C3H\\/He and LPS-resistant C3H\\/HeJ mice. Intraperitoneal injection of 15 of LPS led to a temporary 5- to 6-fold increase in blood nitrate concentration in the C3H\\/He strain. Levels of nitrate excreted in the urine were also increased. In contrast, no increase was observed in the C3H\\/HeJ strain with LPS

D. J. Stuehr; M. A. Marletta



Role of platelet-activating factor (PAF) and prostaglandins in colonic motor and secretory disturbances induced by Escherichia coli endotoxin in conscious rats.  


The involvement of prostaglandins (PGs) and platelet-activating factor (PAF) in the effects of Escherichia coli endotoxin on colonic motility, transit time, and fecal dry matter (DM) in rats were evaluated in this study. Myoelectric activity was investigated in a first group of male Wistar rats chronically implanted with intraparietal nichrome electrodes in the proximal colon. A second group of animals was chronically fitted with an intracolonic catheter (+2 cm from the cecocolonic junction); colonic transit time was then calculated as the Mean Retention Time (MRT) of 51Cr chromate sodium (1 microCi 0.1ml) administered through the intracolonic catheter and determined in the faeces collected at 1 hour interval on a conveyor belt. Fecal DM was measured after 24h dessication at 103 degrees C. E. coli endotoxin (50 micrograms/kg ip) increased the frequency of colonic contractions and decreased both colonic MRT and fecal DM. PAF (25 micrograms/kg ip) also decreased colonic MRT and fecal DM, and increased the frequency of colonic contractions. BN 50730 (10 mg/kg ip), a specific PAF receptor antagonist, blocked the effects of PAF and reduced those of endotoxin on colonic motility and transit time, but did not affect either the endotoxin- or the PAF-induced fecal DM decrease. Indomethacin (10 mg/kg ip) and SC 19220 (5 mg/kg ip) reduced the increased frequency of colonic contractions induced by endotoxin and PAF, and antagonized their effects on MRT and fecal DM. These results indicate that 1) E. coli endotoxin increases both colonic motility and transit, and decreases fecal DM, 2) PAF displays similar effects, 3) the action of endotoxin on colonic motility and transit is partly mediated by PAF and PGs while its secretory effects only depend upon PGs generation. PMID:8016383

Pons, L; Droy-Lefaix, M T; Buéno, L



Antigenic and immunogenic differences in lipopolysaccharides of Escherichia coli J5 vaccine strains of different origins.  


Escherichia coli strain J5 mutants of various origins have often been used as vaccines for induction of cross-reactive, cross-protective antibodies directed against the lipopolysaccharide (LPS) core region. The antigenic composition of LPS from J5 strains of different origin, i.e. strains J5(U), J5(UK), J5(2877) and J5(a), was investigated using monoclonal antibodies (mAbs) reactive only with LPS of a given chemotype, i.e. one specific for the incomplete E. coli core of the Rc chemotype, a second mAb reactive only with the E. coli R3 complete core, and a third specific for the O-antigen of E. coli serovar O111. The LPS of strains J5(U) and J5(a) is almost exclusively composed of LPS of the Rc chemotype, LPS of the J5(UK) strain is composed of Rc LPS and R3 complete core, while LPS of the J5(2877) strain contains Rc, R3 complete core and O-antigen. Growth of the bacteria in medium supplemented with galactose led to increased expression of complete core. The immune responses to the various strains were investigated. Antiserum to the J5 strain expressing the largest amount of R3 core [J5(UK)] had much higher anti-R3 LPS antibody titres compared to antiserum to the other strains. mAb 53, representative of the anti-R3 response to J5 strains containing complete core, bound to those E. coli LPS expressing the R3 core. Thus, the R3 LPS, present in some J5 vaccine strains is at least partially responsible for some of the cross-reactivities exhibited by some anti-J5 antisera.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7506295

Appelmelk, B J; Maaskant, J J; Verweij-van Vught, A M; van der Meer, N M; Thijs, B G; MacLaren, D M



Role of free radicals and platelet-activating factor in the genesis of intestinal motor disturbances induced by Escherichia coli endotoxins in rats.  


The effects of IV administration of Escherichia coli endotoxin on intestinal myoelectric activity was investigated in conscious fasted rats chronically implanted with nichrome electrodes in the duodenojejunum. These effects were compared with those of platelet-activating factor and were evaluated in animals pretreated with a specific platelet-activating factor antagonist, BN 52021, indomethacin, a selective prostaglandin E2 antagonist, SC 19220, and several free radical scavengers. Intravenous administration of endotoxin (E. coli S.O111:B4) at a dose of 50 micrograms/kg suppressed the migrating myoelectric complexes, which were replaced by continuous rhythmic clusters of rapidly propagated spike bursts for 114.7 +/- 19.9 minutes. Intraperitoneal platelet-activating factor (25 micrograms/kg) also inhibited the migrating myoelectric complex pattern for 146.1 +/- 24.1 minutes. Previous IV administration of BN 52021 (50 mg/kg-1) abolished the motor alterations induced by platelet-activating factor and significantly reduced to 43.1 +/- 12.2 minutes those induced by endotoxin (P less than 0.01). Indomethacin (10 mg/kg IP), injected before endotoxin or platelet-activating factor, also significantly reduced the duration of migrating myoelectric complex inhibition to 45.6 +/- 7.8 and 47.7 +/- 8.3 minutes, respectively (P less than 0.01). SC 19220 significantly reduced the effects of platelet-activating factor from 151.8 +/- 26.4 to 67.4 +/- 14.7 min (P less than 0.01). Superoxide dismutase (15,000 U/kg IV) injected before either endotoxin or platelet-activating factor shortened the migrating myoelectric complex inhibition to 45.7 +/- 9.9 and 72.9 +/- 10.4 minutes, respectively (P less than 0.01). Allopurinol and dimethylsulfoxide administered orally at 50 mg/kg 1 hour before endotoxin reduced the migrating myoelectric complex inhibition to 42.5 +/- 6.5 and 38.2 +/- 6.4 minutes, respectively (P less than 0.01). They also reduced platelet-activating factor-induced intestinal myoelectric alterations to 68.5 +/- 10.6 and 31.7 +/- 6.1 minutes, respectively (P less than 0.01). It is concluded that endogenous release of platelet-activating factor is partly responsible for the intestinal motor alterations induced by endotoxin, these effects being also mediated through the release of prostaglandins and free radicals. However, prostaglandins, as well as free radicals, appear to be partly involved in the platelet-activating factor-induced action of E. coli endotoxin on intestinal motility. PMID:1672116

Pons, L; Droy-Lefaix, M T; Braquet, P; Bueno, L



The effect of Escherichia coli lipopolysaccharide and Tumor Necrosis Factor alpha on ovarian function  

PubMed Central

Problem Pelvic inflammatory disease and metritis are important causes of infertility in humans and domestic animals. Uterine infection with Escherichia coli in cattle is associated with reduced ovarian follicle growth and decreased estradiol secretion. We hypothesized that this effect could be mediated by the bacterial lipopolysaccharide (LPS) or cytokines such as tumor necrosis factor alpha (TNF?). Method of study In vitro, bovine ovarian theca and granulosa cells were treated with LPS or TNF? and steroid secretion measured. In vivo, the effect of LPS or TNF? intrauterine infusion was determined by ovarian ultrasonography and measurement of hormones in cattle. Results LPS reduced granulosa cell estradiol secretion, whilst TNF? decreased theca and granulosa cell androstenedione and estradiol production, respectively. In vivo, fewer animals ovulated following intrauterine infusion with LPS or TNF?. Conclusion LPS and TNF? suppress ovarian cell function, supporting the concept that pelvic inflammatory disease and metritis are detrimental for bovine ovarian health. PMID:19238751

Williams, Erin J.; Sibley, Kelly; Miller, Aleisha N.; Lane, Elizabeth A.; Fishwick, John; Nash, Deborah M.; Herath, Shan; England, Gary CW; Dobson, Hilary; Sheldon, I. Martin



Human Antiserum for Prevention of the Local Shwartzman Reaction and Death from Bacterial Lipopolysaccharides  

PubMed Central

Bacterial lipopolysaccharides from dead bacteria have been blamed for the continuing high mortality from gram-negative infections despite antibiotic treatment. Because animal antiserum against these lipopolysaccharides has been shown to protect against several of the effects of endotoxin, we undertook the development of antiserum in human subjects. 21 men were immunized with a single injection of Salmonclla typhimurium or Escherichia coli 0:111 heat-killed cells and immune serum was collected at 2 wk. Preimmune serum was obtained as a control in all animal experiments. 1 ml antiserum given intravenously protected mice against a lethal intravenous dose of homologous endotoxin (P < 0.005 for both antisera). E. coli antiserum reduced the incidence of positive local Shwartzman reactions with E. coli endotoxin from 100 to 38%; S. typhimurium antiserum reduced the incidence from 92 to 35%. (P < 0.0005 for both antisera). There was no protection against heterologous endotoxin in either animal model. These experiments demonstrate for the first time that human antiserum confers exceedingly potent passive immunity to the effects of endotoxin. PMID:4584346

Ziegler, Elizabeth J.; Douglas, Herndon; Braude, Abraham I.



Bladder instillation of Escherichia coli lipopolysaccharide alters the muscle contractions in rat urinary bladder via a protein kinase C-related pathway  

SciTech Connect

Uropathogenic Escherichia coli is a common cause of urinary tract infection. We determined the effects of intravesical instillation of E. coli lipopolysaccharide (LPS, endotoxin) on muscle contractions, protein kinase C (PKC) translocation, and inducible nitric oxide synthase (iNOS) expression in rat urinary bladder. The contractions of the isolated rat detrusor muscle evoked by electrical field stimulations were measured short-term (1 h) or long-term (24 h) after intravesical instillation of LPS. One hour after LPS intravesical instillation, bladder PKC-{alpha} translocation from cytosolic fraction to membrane fraction and endothelial (e)NOS protein was elevated, and detrusor muscle contractions were significantly increased. PKC inhibitors chelerythrine and Ro32-0432 inhibited this LPS-enhanced contractile response. Application of PKC activator {beta}-phorbol-12,13-dibutyrate enhanced the muscle contractions. Three hours after intravesical instillation of LPS, iNOS mRNA was detected in the bladder. Immunoblotting study also demonstrated that the induction of iNOS proteins is detected in bladder in which LPS was instilled. 24 h after intravesical instillation of LPS, PKC-{alpha} translocation was impaired in the bladder; LPS did not affect PKC-{delta} translocation. Muscle contractions were also decreased 24 h after LPS intravesical instillation. Aminoguanidine, a selective iNOS inhibitor, blocked the decrease in PKC-{alpha} translocation and detrusor contractions induced by LPS. These results indicate that there are different mechanisms involved in the alteration of urinary bladder contractions after short-term and long-term treatment of LPS; an iNOS-regulated PKC signaling may participate in causing the inhibition of muscle contractions in urinary bladder induced by long-term LPS treatment.

Weng, T.I. [Institute of Toxicology, College of Medicine, National Taiwan University, No. 1, Section 1, Jen-Ai Road, Taipei, 10043, Taiwan (China); Department of Emergency Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan (China); Chen, W.J. [Department of Emergency Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan (China); Liu, S.H. [Institute of Toxicology, College of Medicine, National Taiwan University, No. 1, Section 1, Jen-Ai Road, Taipei, 10043, Taiwan (China)]. E-mail:



Enhanced toxicity for mice of 6-mercaptopurine with bacterial endotoxin.  


The toxicity of 6-mercaptopurine was potentiated by 2 mg of either Escherichia coli 026:B6 B endotoxin or Salmonella typhosa 0901 W endotoxin per kg. Nonlethal doses of heat-killed, gram-negative bacteria were also capable of potentiating the lethality of 6-mercaptopurine (6-MP). Salmonella minnesota S, the wild-type strain, and S. minnesota Re 595, a mutant containing only the lipid A and 2-keto-3-deoxyoctonate moiety of the endotoxin molecule, exhibited the same capability to enhance the toxic action of 6-MP. Endotoxin (lipopolysaccharide [LPS]) did not affect the clearance of 6-MP from the circulation, but did alter its apparent metabolism as indicated by blood levels of a metabolite, 6-thiouric acid. The concentration of blood urea nitrogen (BUN) in mice 18 h after injection of 100 mg of 6-MP per kg simultaneously with 2 mg of LPS per kg was significantly elevated over normal values. However, these BUN values were significantly less than those resulting from the administration of one mean lethal dose of either agent. The clearance from the circulation of the gram-negative organism E. coli HB, or the gram-positive organism Staphylococcus epidermidis S, was not affected by 6-MP. Endotoxin had no effect on the clearance of S. epidermidis S, but inhibited that of E. coli HB. When 6-MP and LPS were administered simultaneously with either bacterial species, only the clearance of E. coli HB was inhibited. Mice were protected from the lethality associated with combinations of 6-MP and LPS by (i) prior treatment with phenobarbital, (ii) caffeine, (iii) methylprednisolone, and (iv) polymyxin B sulfate. With the exception of caffeine, each regimen protected mice against the lethal effects of 400 mg of 6-MP per kg, and methylprednisolone or polymyxin B protected mice against 8 mg of LPS per kg. PMID:15825398

Marecki, N M; Bradley, S G



Nasal provocation test (NPT) with isolated and associated Dermatophagoides pteronyssinus (Dp) and Endotoxin lipopolysaccharide (LPS) in children with allergic rhinitis (AR) and nonallergic controls  

Microsoft Academic Search

Background: Inhalation of endotoxin may enhance inflammatory airway response in sensitized asthmatics persons after allergen(s) inhalation. Objective: To evaluate nasal response to intranasal instillation of Dermatophagoides pteronyssinus (Dp), endotoxin (LPS), and to Dp+LPS in children with perennial allergic rhinitis (PAR). Methods: 10 PAR children (positive skin prick test to Dp) and 10 nonallergic controls (C) undergoing nasal provocation test (NPT),

C. R. Braga; M. C. V. Rizzo; C. K. Naspitz; D. Solé


Molecular and Structural Basis of Inner Core Lipopolysaccharide Alterations in Escherichia coli  

PubMed Central

It is well established that lipopolysaccharide (LPS) often carries nonstoichiometric substitutions in lipid A and in the inner core. In this work, the molecular basis of inner core alterations and their physiological significance are addressed. A new inner core modification of LPS is described, which arises due to the addition of glucuronic acid on the third heptose with a concomitant loss of phosphate on the second heptose. This was shown by chemical and structural analyses. Furthermore, the gene whose product is responsible for the addition of this sugar was identified in all Escherichia coli core types and in Salmonella and was designated waaH. Its deduced amino acid sequence exhibits homology to glycosyltransferase family 2. The transcription of the waaH gene is positively regulated by the PhoB/R two-component system in a growth phase-dependent manner, which is coordinated with the transcription of the ugd gene explaining the genetic basis of this modification. Glucuronic acid modification was observed in E. coli B, K12, R2, and R4 core types and in Salmonella. We also show that the phosphoethanolamine (P-EtN) addition on heptose I in E. coli K12 requires the product of the ORF yijP, a new gene designated as eptC. Incorporation of P-EtN is also positively regulated by PhoB/R, although it can occur at a basal level without a requirement for any regulatory inducible systems. This P-EtN modification is essential for resistance to a variety of factors, which destabilize the outer membrane like the addition of SDS or challenge to sublethal concentrations of Zn2+. PMID:23372159

Klein, Gracjana; Müller-Loennies, Sven; Lindner, Buko; Kobylak, Natalia; Brade, Helmut; Raina, Satish



An overview of species differences in the effects of a water extract of cotton bract on isolated airway smooth muscle, and effects of E. coli lipopolysaccharide.  

PubMed Central

Our laboratory has been comparing the activity of a water extract of cotton bract (CBE) with the isolated trachealis smooth muscle of the dog, guinea pig, and cat. CBE induced contractions that were not mediated by 5-hydroxytryptamine (5-HT), histamine, or muscarinic receptors. The active agent(s) in CBE was dialyzable (less than 14,000 molecular weight), and substantial activity was retained after low-temperature ashing. CBE potentiated contractions of dog trachealis to histamine and 5-HT and relaxation responses to isoproterenol, whereas it had no effect on responses to methacholine and KCl. In the guinea pig trachealis, CBE reduced responsiveness to KCl, potentiated relaxations to adenosine and ATP, and did not alter the responses to the remaining agents. Responses of cat trachealis to KCl and isoproterenol were potentiated by CBE, while those to 5-HT were unaffected. Neurogenic cholinergic contractile responses were potentiated by CBE in the trachealis of the dog, but not of the guinea pig, while neurogenic relaxations were potentiated by CBE in guinea pig trachealis but not in the dog trachealis. There are thus marked species differences in the acute effects of CBE on airway smooth muscle. Due to recent interest in the possible involvement of bacterial endotoxins in the etiology of byssinosis, we examined the effects of E. coli lipopolysaccharide (LPS) in guinea pig trachealis. An initial examination revealed that LPS potentiated responses to histamine, but not those to methacholine and isoproterenol. This effect vanished upon a second appraisal with a different batch of LPS. The effect of LPS in airway smooth muscle is thus, at present, equivocal. PMID:3011394

Fedan, J S; Robinson, V A; Hay, D W; Weber, K C



Systemic E. coli lipopolysaccharide but not deoxynivalenol results in transient leukopenia and diminished metabolic activity of peripheral blood mononuclear cells ex vivo.  


The mycotoxin deoxynivalenol (DON) and lipopolysaccharides (LPS) are reported to act synergistically in the animal organism. Thus, we tested the hypothesis that systemic co-exposure of DON and LPS aggravates the impact of the individual toxin on leukocyte counts in vivo and peripheral blood mononuclear cells (PBMC) ex vivo. Growing barrows were fed a standard diet, equipped with permanent venous catheters and infused for 1 h with one of four treatments: control group with physiological saline (CON, n=8), mycotoxin group (DON, n=6) with 100 ?g/kg body weight (BW) deoxynivalenol, endotoxin group (LPS, n=6) with 7.5 ?g/kg BW Escherichia coli LPS, and co-exposed group (DON+LPS, n=6) with 100 ?g/kg BW DON and 7.5 ?g/kg BW LPS. Blood was collected 30 min prior to infusion and 10, 20, 30, 60, 360, 720 and 1440 min after start of infusion for total and differential leukocyte counts. PBMC were isolated from blood drawn at 3 and 24 h and subjected to an ex vivo 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay, either non-stimulated or stimulated with concanavalin A. LPS induced a transient significant leukopenia between 30 and 360 min, owing to a decrease in segmented neutrophils and lymphocytes (time×treatment: p<0.001). Metabolic activity of stimulated PBMC ex vivo was severely compromised in pigs 3 h after LPS exposure (<50% of control, p<0.001), but already regained 80% of its activity at 24 h, thus showing no difference between treatments. DON alone did not affect leukocytes in vivo or PBMC activity ex vivo and neither aggravated the effect of LPS. PMID:25315977

Kluess, Jeannette; Kahlert, Stefan; Panther, Patricia; Diesing, Anne-Kathrin; Nossol, Constanze; Rothkötter, Hermann-Josef; Kersten, Susanne; Dänicke, Sven



The induction of nitric oxide synthase and intestinal vascular permeability by endotoxin in the rat.  

PubMed Central

1. The effect of endotoxin (E. coli lipopolysaccharide) on the induction of nitric oxide synthase (NOS) and the changes in vascular permeability in the colon and jejunum over a 5 h period have been investigated in the rat. 2. Under resting conditions, a calcium-dependent constitutive NOS, determined by the conversion of radiolabelled L-arginine to citrulline, was detected in homogenates of both colonic and jejunal tissue. 3. Administration of endotoxin (3 mg kg-1, i.v.) led, after a 2 h lag period, to the appearance of calcium-independent NOS activity in the colon and jejunum ex vivo, characteristic of the inducible NOS enzyme. 4. Administration of endotoxin led to an increase in colonic and jejunal vascular permeability after a lag period of 3 h, determined by the leakage of radiolabelled albumin. 5. Pretreatment with dexamethasone (1 mg kg-1 s.c., 2 h prior to challenge) inhibited both the induction of NOS and the vascular leakage induced by endotoxin. 6. Administration of the NO synthase inhibitor NG-monomethyl-L-arginine (12.5-50 mg kg-1, s.c.) 3 h after endotoxin injection, dose-dependently reduced the subsequent increase in vascular permeability in jejunum and colon, an effect reversed by L-arginine (300 mg kg-1, s.c.). 7. These findings suggest that induction of NOS is associated with the vascular injury induced by endotoxin in the rat colon and jejunum. PMID:7507778

Boughton-Smith, N. K.; Evans, S. M.; Laszlo, F.; Whittle, B. J.; Moncada, S.



Residual Endotoxin Contaminations in Recombinant Proteins Are Sufficient to Activate Human CD1c+ Dendritic Cells  

PubMed Central

Many commercially available recombinant proteins are produced in Escherichia coli, and most suppliers guarantee contamination levels of less than 1 endotoxin unit (EU). When we analysed commercially available proteins for their endotoxin content, we found contamination levels in the same range as generally stated in the data sheets, but also some that were higher. To analyse whether these low levels of contamination have an effect on immune cells, we stimulated the monocytic cell line THP-1, primary human monocytes, in vitro differentiated human monocyte-derived dendritic cells, and primary human CD1c+ dendritic cells (DCs) with very low concentrations of lipopolysaccharide (LPS; ranging from 0.002–2 ng/ml). We show that CD1c+ DCs especially can be activated by minimal amounts of LPS, equivalent to the levels of endotoxin contamination we detected in some commercially available proteins. Notably, the enhanced endotoxin sensitivity of CD1c+ DCs was closely correlated with high CD14 expression levels observed in CD1c+ DCs that had been maintained in cell culture medium for 24 hours. When working with cells that are particularly sensitive to LPS, even low endotoxin contamination may generate erroneous data. We therefore recommend that recombinant proteins be thoroughly screened for endotoxin contamination using the limulus amebocyte lysate test, fluorescence-based assays, or a luciferase based NF-?B reporter assay involving highly LPS-sensitive cells overexpressing TLR4, MD-2 and CD14. PMID:25478795

Schwarz, Harald; Schmittner, Maria; Duschl, Albert; Horejs-Hoeck, Jutta



Removal of Endotoxins from Bacteriophage Preparations by Extraction with Organic Solvents  

PubMed Central

Lipopolysaccharide (LPS, endotoxin, pyrogen) constitutes a very troubling contaminant of crude phage lysates produced in Gram-negative bacteria. Toxicity of LPS depends on the strong innate immunity response including the cytokines. Therefore, its removal is important for bacteriophage applications. In this paper, we present a procedure for extractive removal of endotoxin from bacteriophage preparations with water immiscible solvents (1-octanol or 1-butanol). During extraction most of the phage lytic activity is retained in the aqueous phase, while endotoxin accumulates in the organic solvent. The levels of endotoxin (expressed as endotoxin units, EU) in the aqueous bacteriophage-containing fraction determined by limulus amebocyte lysate or EndoLISA assay were exceptionally low. While the initial endotoxin levels in the crude phage lysates ranged between 103 and 105 EU/ml the average level after organic extraction remaining in the aqueous fraction was 5.3 EU/ml. These values when related to phage titers decreased from 103-105 EU/109 PFU (plaque forming units) down to an average of 2.8 EU/109 PFU. The purification procedure is scalable, efficient and applicable to all the bacteriophages tested: T4, HAP1 (E. coli) and F8 (P. aeruginosa). PMID:25811193

Szermer-Olearnik, Bo?ena; Boraty?ski, Janusz



Pharmacokinetics of florfenicol after intravenous administration in Escherichia coli lipopolysaccharide-induced endotoxaemic sheep.  


Experiments in different animal species have shown that febrile conditions, induced by Escherichia coli lipopolysaccharide (LPS), may alter the pharmacokinetic properties of drugs. The objective was to study the effects of a LPS-induced acute-phase response (APR) model on plasma pharmacokinetics of florfenicol (FFC) after its intravenous administration in sheep. Six adult clinically healthy Suffolk Down sheep, 8 months old and 35.5 ± 2.2 kg in body weight (bw), were distributed through a crossover factorial 2 × 2 design, with 4 weeks of washout. Pairs of sheep similar in body weight were assigned to experimental groups: Group 1 (LPS) was treated with three intravenous doses of 1 ?g/kg bw of E. coli LPS before FFC treatment. Group 2 (control) was treated with an equivalent volume of saline solution (SS) at similar intervals as LPS. At 24 h after the first injection of LPS or SS, an intravenous bolus of 20 mg/kg bw of FFC was administered. Blood samples (5 mL) were collected before drug administration and at different times between 0.05 and 48.0 h after treatment. FFC plasma concentrations were determined by liquid chromatography. A noncompartmental pharmacokinetic model was used for data analysis, and data were compared using a Mann-Whitney U-test. The mean values of AUC0-? in the endotoxaemic sheep (105.9 ± 14.3 ?g·h/mL) were significantly higher (P < 0.05) than values observed in healthy sheep (78.4 ± 5.2 ?g·h/mL). The total mean plasma clearance (CLT ) decreased from 257.7 ± 16.9 mL·h/kg in the control group to 198.2 ± 24.1 mL·h/kg in LPS-treated sheep. A significant increase (P < 0.05) in the terminal half-life was observed in the endotoxaemic sheep (16.9 ± 3.8 h) compared to the values observed in healthy sheep (10.4 ± 3.2 h). In conclusion, the APR induced by the intravenous administration of E. coli LPS in sheep produces higher plasma concentrations of FFC due to a decrease in the total body clearance of the drug. PMID:25229993

Pérez, R; Palma, C; Drápela, C; Sepulveda, M; Espinoza, A; Peńailillo, A K



Acidosis and lipopolysaccharide from Escherichia coli B:055 cause hyperpermeability of rumen and colon tissues.  


The objective of the present investigation was to evaluate the effects of acidic pH of the perfusate and presence of lipopolysaccharide (LPS) on permeability of rumen and colon mucosal tissues to mannitol and LPS using the Ussing chamber system. Rumen and colon tissues (n = 8), obtained from slaughtered feedlot steers, were tested for changes in permeability to (3)H-mannitol under pH of 4.5, 5.5, and 6.5 for rumen and at 5.5, 6.5, and 7.4 for colon, with or without LPS from Escherichia coli B:055 at 500 microg/mL. The (3)H-Mannitol was added at 10 microL (525.4 GBq/mmol) on the mucosal side of the Ussing chamber to detect changes in permeability, and 4 samples were taken at 20, 25, 30, and 35 min from the serosal side. Permeability of rumen and colon mucosa to (3)H-mannitol increased 6- and 5-fold, respectively, at acidic pH values of 4.5 and 5.5 and in the presence of 500 micro/mL of LPS. In contrast, LPS did not affect rumen and colon permeability at pH that ranged from 5.5 and 7.4. Translocation of LPS across the rumen and colon mucosa of cattle was not pH dependent. The LPS translocated through these tissues if present at the mucosal side. In conclusion, the permeability of rumen and colon tissues to (3)H-mannitol increased in presence of LPS and under acidic pH, whereas LPS permeated through mucosal tissues independently of the pH of the perfusate. Further research is warranted to understand the mechanism(s) by which acidic pH of the rumen digesta and presence of LPS make rumen and colon tissues "leaky". PMID:18024746

Emmanuel, D G V; Madsen, K L; Churchill, T A; Dunn, S M; Ametaj, B N



Proteolytic and proteomic changes in milk at quarter level following infusion with Escherichia coli lipopolysaccharide.  


Mastitis is a major disease in dairy cattle, which causes significant economic losses due to decreased milk production, veterinary costs, and discarded milk. Escherichia coli is one of the most prevalent species of gram-negative bacteria that induce clinical mastitis. The objective of the present study was to characterize the proteolytic and proteomic changes in milk in response to infusion with lipopolysaccharide (LPS) at quarter level in a model mastitis system. One quarter of each of 2 cows was infused with 0.1 or 5 ?g of LPS. The somatic cell count of the infused quarters reached a peak 6 h after infusion to a greater extent in the cow infused with 5 ?g of LPS and changes in plasmin activity in milk differed between the 2 animals. Urea-polyacrylamide gel electrophoretograms of milk samples of the cow infused with 5 ?g of LPS obtained at different time points after infusion and incubated for up to 7 d showed almost full hydrolysis of ?- and ?(s1)-casein during incubation of milk samples due to indigenous proteolytic activity. Two-dimensional gel electrophoretograms of milk at 0, 6, or 12 h after infusion with LPS showed hydrolysis of ?(s)-casein and ?-casein as well as the appearance of lower molecular weight products. Eleven fragments from proteolysis of the caseins were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and, in addition, proteolysis patterns of casein by the indigenous bovine milk proteases plasmin and cathepsin D were studied in model studies using 2-dimensional gel electrophoretograms. Twelve hours after infusion, lower abundance markers of inflammation were identified, including serotransferrin, fibrinogen ? chain, protein S100 A12, and the antimicrobial polypeptide cathelicidin. PMID:22459814

Hinz, K; Larsen, L B; Wellnitz, O; Bruckmaier, R M; Kelly, A L



Borrelia burgdorferi and Escherichia coli lipopolysaccharides induce nitric oxide and interleukin-6 production in cultured rat brain cells.  


Borrelia burgdorferi, the spirochetal agent of Lyme disease, infects the central nervous system (CNS), but the factors that mediate inflammation and neurologic dysfunction are not known. Sonicated B. burgdorferi stimulated in a concentration-dependent manner the production of nitric oxide (NO) in glial-enriched primary cultures of neonatal rat brain cells via induction of NO synthase activity. Lipopolysaccharide (LPS) of Escherichia coli also stimulated nitrite accumulation in a concentration-dependent manner. Stimulation of NO production by B. burgdorferi sonicate and E. coli LPS was associated with increased levels of mRNA coding for the cytokine-inducible form of NO synthase. B. burgdorferi sonicate also stimulated release of interleukin-6, with a concentration-response relationship similar to that for its stimulation of nitrite production, as did E. coli LPS. A competitive antagonist of E. coli LPS, Rhodopseudomonas sphaeroides lipid A, inhibited LPS-induced stimulation of NO synthase activity but markedly potentiated that of B. burgdorferi, indicating that the initial triggering mechanism of B. burgdorferi is distinct from that of E. coli LPS. Induction of NO synthase by bacterial agents within the brain may represent a common pathway of CNS inflammation and neurotoxicity. PMID:7513330

Tatro, J B; Romero, L I; Beasley, D; Steere, A C; Reichlin, S



Assembly of lipopolysaccharide in Escherichia coli requires the essential LapB heat shock protein.  


Here, we describe two new heat shock proteins involved in the assembly of LPS in Escherichia coli, LapA and LapB (lipopolysaccharide assembly protein A and B). lapB mutants were identified based on an increased envelope stress response. Envelope stress-responsive pathways control key steps in LPS biogenesis and respond to defects in the LPS assembly. Accordingly, the LPS content in ?lapB or ?(lapA lapB) mutants was elevated, with an enrichment of LPS derivatives with truncations in the core region, some of which were pentaacylated and exhibited carbon chain polymorphism. Further, the levels of LpxC, the enzyme that catalyzes the first committed step of lipid A synthesis, were highly elevated in the ?(lapA lapB) mutant. ?(lapA lapB) mutant accumulated extragenic suppressors that mapped either to lpxC, waaC, and gmhA, or to the waaQ operon (LPS biosynthesis) and lpp (Braun's lipoprotein). Increased synthesis of either FabZ (3-R-hydroxymyristoyl acyl carrier protein dehydratase), slrA (novel RpoE-regulated non-coding sRNA), lipoprotein YceK, toxin HicA, or MurA (UDP-N-acetylglucosamine 1-carboxyvinyltransferase) suppressed some of the ?(lapA lapB) defects. LapB contains six tetratricopeptide repeats and, at the C-terminal end, a rubredoxin-like domain that was found to be essential for its activity. In pull-down experiments, LapA and LapB co-purified with LPS, Lpt proteins, FtsH (protease), DnaK, and DnaJ (chaperones). A specific interaction was also observed between WaaC and LapB. Our data suggest that LapB coordinates assembly of proteins involved in LPS synthesis at the plasma membrane and regulates turnover of LpxC, thereby ensuring balanced biosynthesis of LPS and phospholipids consistent with its essentiality. PMID:24722986

Klein, Gracjana; Kobylak, Natalia; Lindner, Buko; Stupak, Anna; Raina, Satish



Synthesis of the Tetrasaccharide Motif and Its Structural Analog Corresponding to the Lipopolysaccharide of Escherichia coli O75  

PubMed Central

Background Extraintestinal pathogenic E. coli are mostly responsible for a diverse spectrum of invasive human and animal infections leading to the urinary tract infections. Bacterial lipopolysaccharides are responsible for their pathogenicity and their interactions with host immune responses. In spite of several breakthroughs in the development of therapeutics to combat urinary tract infections and related diseases, the emergence of multidrug-resistant bacterial strains is a serious concern. Lipopolysaccharides are attractive targets for the development of long-term therapeutic agents to eradicate the infections. Since the natural sources cannot provide the required amount of oligosaccharides, development of chemical synthetic strategies for their synthesis is relevant to gain access to a reservoir of oligosaccharides and their close analogs. Methodology Two tetrasaccharide derivatives were synthesized from a single disaccharide intermediate. ?-d-mannoside moiety was prepared from ?-d-glucoside moiety following oxidation–reduction methodology. A [2+2] stereoselective block glycosylation strategy has been adopted for the preparation of tetrasaccharide derivative. ?-d-Glucosamine moiety was prepared from ?-d-mannosidic moiety following triflate formation at C-2 and SN2 substitution. A one-pot iterative glycosylation exploiting the orthogonal property of thioglycoside was carried out during the synthesis of tetrasaccharide analog. Results Synthesis of the tetrasaccharide motif (1) and its structural analog (2) corresponding to the lipopolysaccharide of Escherichia coli O75 was successfully achieved in excellent yield. Most of the reactions are clean and high yielding. Both compounds 1 and 2 were synthesized as their 4-methoxyphenyl glycoside, which can act as a temporary anomeric protecting group for further use of these tetrasaccharides in the preparation of glycoconjugates. PMID:22662142

Sau, Abhijit; Misra, Anup Kumar



Efficacy of a novel endotoxin adsorber polyvinylidene fluoride fiber immobilized with l-serine ligand on septic pigs*  

PubMed Central

A novel adsorber, polyvinylidene fluoride matrix immobilized with l-serine ligand (PVDF-Ser), was developed in the present study to evaluate its safety and therapeutic efficacy in septic pigs by extracorporeal hemoperfusion. Endotoxin adsorption efficiency (EAE) of the adsorber was firstly measured in vitro. The biocompatibility and hemodynamic changes during extracorporeal circulation were then evaluated. One half of 16 pigs receiving lipopolysaccharide (Escherichia coli O111:B4, 5 ?g/kg) intravenously in 1 h were consecutively treated by hemoperfusion with the new adsorber for 2 h. The changes of circulating endotoxin and certain cytokines and respiratory function were analyzed. The 72 h-survival rate was assessed eventually. EAE reached 46.3% (100 EU/ml in 80 ml calf serum) after 2 h-circulation. No deleterious effect was observed within the process. The plasma endotoxin, interleukin-6 (IL-6), and tumor necrosis factor-? (TNF-?) levels were decreased during the hemoperfusion. Arterial oxygenation was also improved during and after the process. Furthermore, the survival time was significantly extended (>72 h vs. 47.5 h for median survival time). The novel product PVDF-Ser could adsorb endotoxin with high safety and efficacy. Early use of extracorporeal hemoperfusion with the new adsorber could reduce the levels of circulating endotoxin, IL-6, and TNF-?, besides improve respiratory function and consequent 72 h-survival rate of the septic pigs. Endotoxin removal strategy with blood purification using the new adsorber renders a potential promising future in sepsis therapy. PMID:21462381

Gao, Jian-ping; Huang, Man; Li, Ning; Wang, Peng-fei; Chen, Huan-lin; Xu, Qiu-ping



Naturally occurring hypothermia is more advantageous than fever in severe forms of lipopolysaccharide- and Escherichia coli-induced systemic inflammation.  


The natural switch from fever to hypothermia observed in the most severe cases of systemic inflammation is a phenomenon that continues to puzzle clinicians and scientists. The present study was the first to evaluate in direct experiments how the development of hypothermia vs. fever during severe forms of systemic inflammation impacts the pathophysiology of this malady and mortality rates in rats. Following administration of bacterial lipopolysaccharide (LPS; 5 or 18 mg/kg) or of a clinical Escherichia coli isolate (5 × 10(9) or 1 × 10(10) CFU/kg), hypothermia developed in rats exposed to a mildly cool environment, but not in rats exposed to a warm environment; only fever was revealed in the warm environment. Development of hypothermia instead of fever suppressed endotoxemia in E. coli-infected rats, but not in LPS-injected rats. The infiltration of the lungs by neutrophils was similarly suppressed in E. coli-infected rats of the hypothermic group. These potentially beneficial effects came with costs, as hypothermia increased bacterial burden in the liver. Furthermore, the hypotensive responses to LPS or E. coli were exaggerated in rats of the hypothermic group. This exaggeration, however, occurred independently of changes in inflammatory cytokines and prostaglandins. Despite possible costs, development of hypothermia lessened abdominal organ dysfunction and reduced overall mortality rates in both the E. coli and LPS models. By demonstrating that naturally occurring hypothermia is more advantageous than fever in severe forms of aseptic (LPS-induced) or septic (E. coli-induced) systemic inflammation, this study provides new grounds for the management of this deadly condition. PMID:22513748

Liu, Elaine; Lewis, Kevin; Al-Saffar, Hiba; Krall, Catherine M; Singh, Anju; Kulchitsky, Vladimir A; Corrigan, Joshua J; Simons, Christopher T; Petersen, Scott R; Musteata, Florin M; Bakshi, Chandra S; Romanovsky, Andrej A; Sellati, Timothy J; Steiner, Alexandre A



Identification of Tn10 insertions in the rfaG, rfaP, and galU genes involved in lipopolysaccharide core biosynthesis that affect Escherichia coli adhesion  

Microsoft Academic Search

Escherichia coli was used as a model to study initial adhesion and early biofilm development to abiotic surface. Tn10 insertion mutants of Escherichia coli K-12 W3110 were selected for altered abilities to adhere to a polystyrene surface. Seven insertion mutants that showed a\\u000a decrease in adhesion harbored insertions in genes involved in lipopolysaccharide (LPS) core biosynthesis. Two insertions were\\u000a located

Pierre Genevaux; Pascale Bauda; Michael S. DuBow; Bauke Oudega



Acidosis and Lipopolysaccharide from Escherichia coli B:055 Cause Hyperpermeability of Rumen and Colon Tissues  

Microsoft Academic Search

The objective of the present investigation was to eval- uate the effects of acidic pH of the perfusate and pres- ence of lipopolysaccharide (LPS) on permeability of ru- men and colon mucosal tissues to mannitol and LPS using the Ussing chamber system. Rumen and colon tissues (n = 8), obtained from slaughtered feedlot steers, were tested for changes in permeability

D. G. V. Emmanuel; K. L. Madsen; T. A. Churchill; S. M. Dunn; B. N. Ametaj




Technology Transfer Automated Retrieval System (TEKTRAN)

The purpose of this study was to determine whether soluble CD14 in milk was affected by stage of lactation, milk somatic cell count (SCC), presence of bacteria or lipopolysaccharide (LPS)-induced inflammation. Milk samples from 100 lactating cows were assayed for sCD14 in milk to determine effects o...


Thoracic epidural anesthesia decreases endotoxin-induced endothelial injury  

PubMed Central

Background The sympathetic nervous system is considered to modulate the endotoxin-induced activation of immune cells. Here we investigate whether thoracic epidural anesthesia with its regional symapathetic blocking effect alters endotoxin-induced leukocyte-endothelium activation and interaction with subsequent endothelial injury. Methods Sprague Dawley rats were anesthetized, cannulated and hemodynamically monitored. E. coli lipopolysaccharide (Serotype 0127:B8, 1.5 mg x kg-1 x h-1) or isotonic saline (controls) was infused for 300 minutes. An epidural catheter was inserted for continuous application of lidocaine or normal saline in endotoxemic animals and saline in controls. After 300 minutes we measured catecholamine and cytokine plasma concentrations, adhesion molecule expression, leukocyte adhesion, and intestinal tissue edema. Results In endotoxemic animals with epidural saline, LPS significantly increased the interleukin-1? plasma concentration (48%), the expression of endothelial adhesion molecules E-selectin (34%) and ICAM-1 (42%), and the number of adherent leukocytes (40%) with an increase in intestinal myeloperoxidase activity (26%) and tissue edema (75%) when compared to healthy controls. In endotoxemic animals with epidural infusion of lidocaine the values were similar to those in control animals, while epinephrine plasma concentration was 32% lower compared to endotoxemic animals with epidural saline. Conclusions Thoracic epidural anesthesia attenuated the endotoxin-induced increase of IL-1? concentration, adhesion molecule expression and leukocyte-adhesion with subsequent endothelial injury. A potential mechanism is the reduction in the plasma concentration of epinephrine. PMID:24708631



The Escherichia coli Lpt Transenvelope Protein Complex for Lipopolysaccharide Export Is Assembled via Conserved Structurally Homologous Domains  

PubMed Central

Lipopolysaccharide is a major glycolipid component in the outer leaflet of the outer membrane (OM), a peculiar permeability barrier of Gram-negative bacteria that prevents many toxic compounds from entering the cell. Lipopolysaccharide transport (Lpt) across the periplasmic space and its assembly at the Escherichia coli cell surface are carried out by a transenvelope complex of seven essential Lpt proteins spanning the inner membrane (LptBCFG), the periplasm (LptA), and the OM (LptDE), which appears to operate as a unique machinery. LptC is an essential inner membrane-anchored protein with a large periplasm-protruding domain. LptC binds the inner membrane LptBFG ABC transporter and interacts with the periplasmic protein LptA. However, its role in lipopolysaccharide transport is unclear. Here we show that LptC lacking the transmembrane region is viable and can bind the LptBFG inner membrane complex; thus, the essential LptC functions are located in the periplasmic domain. In addition, we characterize two previously described inactive single mutations at two conserved glycines (G56V and G153R, respectively) of the LptC periplasmic domain, showing that neither mutant is able to assemble the transenvelope machinery. However, while LptCG56V failed to copurify any Lpt component, LptCG153R was able to interact with the inner membrane protein complex LptBFG. Overall, our data further support the model whereby the bridge connecting the inner and outer membranes would be based on the conserved structurally homologous jellyroll domain shared by five out of the seven Lpt components. PMID:23292770

Villa, Riccardo; Martorana, Alessandra M.; Okuda, Suguru; Gourlay, Louise J.; Nardini, Marco; Sperandeo, Paola; Dehň, Gianni; Bolognesi, Martino; Kahne, Daniel




EPA Science Inventory

Field and laboratory studies were conducted to determine the distribution of algae and bacteria, and investigate sources of endotoxins (lipopolysaccharides) in drinking water. The field survey was performed on five drinking water systems located in Allegheny County, Pennsylvania ...


Monoclonal antibody to endotoxin core protects mice from Escherichia coli sepsis by a mechanism independent of tumor necrosis factor and interleukin-6.  


To study the role of cytokines as mediators of endotoxin-induced shock, the serum levels of tumor necrosis factor (TNF) and interleukin-6 (IL-6) were compared in mice receiving either a monoclonal antibody to endotoxin core (clone 20), an irrelevant monoclonal antibody (A1), or culture media (DMEM/FCS) alone before lethal challenge with live Escherichia coli O111:B4. Clone 20 given 1.5 h before the bacterial challenge protected mice from death (mortality at 48 h 3% vs. 87%, P less than .001). The pattern of IL-6 release was indistinguishable in clone 20 recipients and controls: The area under the curve (AUC) for 5 h was 1.22 +/- 0.07 x 10(6), 1.03 +/- 0.17 x 10(6), and 1.22 +/- 0.07 x 10(6) units/ml for clone 20, A1, and DMEM/FCS, respectively. Similarly, the timing and extent of TNF release in the serum was virtually identical in clone 20 recipients that survived and control animals that died. AUC for 5 h was 30.8 +/- 4.0 x 10(3), 28.1 +/- 1.1 x 10(3), and 30.4 +/- 4.7 x 10(3) ng/ml in clone 20, A1, and DMEM/FCS recipients, respectively. Thus, TNF and IL-6 appear insufficient to cause death in this model of experimental gram-negative shock. PMID:2197338

Silva, A T; Appelmelk, B J; Buurman, W A; Bayston, K F; Cohen, J



Inflammatory response after inhalation of bacterial endotoxin assessed by the induced sputum technique  

Microsoft Academic Search

BACKGROUNDOrganic dusts may cause inflammation in the airways. This study was performed to assess the usefulness of the induced sputum technique for evaluating the presence of airways inflammation using inhaled endotoxin (lipopolysaccharide) as the inducer of inflammation.METHODSTo characterise the inflammatory response after inhalation of endotoxin, 21 healthy subjects inhaled 40 ?g lipopolysaccharide and were examined before and 24 hours after

Jörgen Thorn; Ragnar Rylander



Lipopolysaccharide-Binding Protein Accelerates and Augments Escherichia coli Phagocytosis by Alveolar Macrophages  

Microsoft Academic Search

Background. The first step in bacterial clearance by leukocytes is attachment and phagocytosis. Although lipopolysaccharide-binding protein (LBP) is best known for potentiating LPS-induced cytokine production through a CD14-dependent pathway, recent studies suggest that LBP plays a critical role in clearance of gram-negative bacteria and is essential for survival after bacterial challenge. We therefore sought to examine LBP's effect on Escherichia

Richard D Klein; Grace L Su; Carl Schmidt; Alireza Aminlari; Lars Steinstraesser; William H Alarcon; Hong Yu Zhang; Stewart C Wang



Endotoxin induced uncoupling of the somatotrophic axis in nursery pigs  

Technology Transfer Automated Retrieval System (TEKTRAN)

Lipopolysaccharide (LPS) is an endotoxin known to stimulate the innate immune response and stress axis in pigs. However, little is known about the effects of LPS on pig somatotrophic responses. The objective of this study was to determine the effects of an endotoxin challenge on weaned pig serum con...


The structural characterization of the O-polysaccharide antigen in the lipopolysaccharide of Escherichia coli serotype O118 and its relationship to the O-antigens of Salmonella enterica O47 and Escherichia coli serotype O151  

Technology Transfer Automated Retrieval System (TEKTRAN)

Mild acid hydrolysis of the lipopolysaccharide produced by Escherichia coli O118:H16 (standard reference strain; NRCC 6613) contained an O-polysaccharide (O-PS) composed of D-galactose, 2-acetimidoylamino-2,6-dideoxy-L-galactose (L-FucNAm), 2-acetamido-2-deoxy-D-glucose, ribitol, and phosphate (1:1...


Structural Characterization of a Model Gram-Negative Bacterial Surface Using Lipopolysaccharides from Rough Strains of Escherichia coli  

PubMed Central

Lipopolysaccharides (LPS) make up approximately 75% of the Gram-negative bacterial outer membrane (OM) surface, but because of the complexity of the molecule, there are very few model OMs that include LPS. The LPS molecule consists of lipid A, which anchors the LPS within the OM, a core polysaccharide region, and a variable O-antigen polysaccharide chain. In this work we used RcLPS (consisting of lipid A plus the first seven sugars of the core polysaccharide) from a rough strain of Escherichia coli to form stable monolayers of LPS at the air–liquid interface. The vertical structure RcLPS monolayers were characterized using neutron and X-ray reflectometry, while the lateral structure was investigated using grazing incidence X-ray diffraction and Brewster angle microscopy. It was found that RcLPS monolayers at surface pressures of 20 mN m–1 and above are resolved as hydrocarbon tails, an inner headgroup, and an outer headgroup of polysaccharide with increasing solvation from tails to outer headgroups. The lateral organization of the hydrocarbon lipid chains displays an oblique hexagonal unit cell at all surface pressures, with only the chain tilt angle changing with surface pressure. This is in contrast to lipid A, which displays hexagonal or, above 20 mN m–1, distorted hexagonal packing. This work provides the first complete structural analysis of a realistic E. coli OM surface model. PMID:23617615



Effect of endotoxin administration in pregnant camels  

PubMed Central

Intravenous administration of Escherichia coli endotoxin at a dose of 0.05 ?g/kg bodyweight to pregnant camels resulted in abortion. The injection of endotoxin caused significant increases in the plasma concentration of 13,14-dihydro-15-prostaglandin F2?, the metabolite of prostaglandin F2? (PG F2?) and cortisol and a significant decrease in the concentration of progesterone. It is suggested that endotoxin caused abortion in camels was a consequence of endotoxin induced PG F2? secretion resulting in luteal regression and decreased progesterone concentration. PMID:23961064

AL-Dughaym, A.M.; Homeida, A.M.



Prostaglandin E2 as a read out for endotoxin detection in a bovine whole blood assay.  


The detection of endotoxin contamination is an essential part of drug safety testing. The rabbit pyrogen test (RPT), the limulus amoebocyte lysate (LAL) test, and the monocyte activation test (MAT) are established methods for the detection of pyrogens. However, the RPT is insufficiently standardized; the LAL test is solely capable of identifying the presence of endotoxins, whereas the use of the MAT is limited by the availability of human blood. Here, we introduce a new procedure for testing endotoxin contamination using prostaglandin E2 (PGE2 ) release from bovine whole blood. We incubated bovine whole blood overnight with lipopolysaccharide (LPS) from Escherichia coli 0111:B4, concentrations ranging from 1.56 to 12.5 pg/mL, and found significantly increased PGE2 production for even the lowest LPS concentrations. Testing the possibility of storing the blood at 4 °C before use also yielded positive results as 1.56 pg/mL still significantly increased PGE2 production, thus suggesting some flexibility of the assay regarding time. These results emphasize the potential of using bovine whole blood for highly sensitive endotoxin testing. As a perspective, currently ongoing research aims to show whether the assay is also capable of detecting nonendotoxin pyrogens. PMID:25131599

Wunderlich, C; Schumacher, S; Kietzmann, M



Molecular Characterization of the Locus Encoding Biosynthesis of the Lipopolysaccharide O Antigen of Escherichia coli Serotype O113  

PubMed Central

Shiga toxigenic Escherichia coli (STEC) strains are a diverse group of organisms capable of causing severe gastrointestinal disease in humans. Within the STEC family, eae-positive STEC strains, particularly those belonging to serogroups O157 and O111, appear to have greater virulence for humans. However, in spite of being eae negative, STEC strains belonging to serogroup O113 have frequently been associated with cases of severe STEC disease, including hemolytic-uremic syndrome (HUS). Western blot analysis with convalescent-phase serum from a patient with HUS caused by an O113:H21 STEC strain indicated that human immune responses were directed principally against lipopolysaccharide O antigen. Accordingly, the serum was used to isolate a clone expressing O113 O antigen from a cosmid library of O113:H21 DNA constructed in E. coli K-12. Sequence analysis indicated that the O113 O-antigen biosynthesis (rfb) locus contains a cluster of nine genes which may be cotranscribed. Comparison with sequence databases identified candidate genes for four glycosyl transferases, an O-acetyl transferase, an O-unit flippase, and an O-antigen polymerase, as well as copies of galE and gnd. Two additional, separately transcribed genes downstream of the O113 rfb region were predicted to encode enzymes involved in synthesis of activated sugar precursors, one of which (designated wbnF) was essential for O113 O-antigen synthesis, and so is clearly a part of the O113 rfb locus. Interestingly, expression of O113 O antigen by E. coli K-12 significantly increased in vitro adherence to both HEp-2 and Henle 407 cells. PMID:10531250

Paton, Adrienne W.; Paton, James C.



Dose dependence of endotoxin-induced activation of the plasma contact system: an in vitro study.  


The dose and time dependence of endotoxin-induced activation of the plasma contact system have been studied. Citrated pool plasma was incubated at 37 degrees C with endotoxin doses of 2.10(5), 2.10(6), 2.10(7), and 2.10(9) ng/l (lipopolysaccharide B, E. coli 026: B6, Difco Laboratories, Detroit, MI) for 24 hr. Samples for determination of components of the contact system were obtained prior to incubation and at 1, 2, 4, 6, 12, and 24 hr. Plasma kallikrein (KK) activity markedly increased at 12 hr in test plasma containing the highest dose of endotoxin (2.10(9) ng/l). Coincident with the elevated KK activity, reductions of both plasma prekallikrein (PKK) and functional kallikrein inhibition (KKI) were seen as assayed by chromogenic peptide substrate analyses. Also, functionally determined alpha 2-macroglobulin (alpha 2-M) and C1 inhibitor (C1INH) values were decreased, confirming the reduction of KKI values. Changes of Hageman factor (FXII), PKK, and high molecular weight kininogen (HMWK) values were also found at the same time point when assayed by immunochemical techniques. The same pattern of changes was seen in test plasma containing 2.10(7) and 2.10(6) ng/l of endotoxin. These changes, however, were less pronounced and not seen until 24 hr after beginning incubation. In control plasma and in plasma containing the lowest dose of endotoxin (2.10(5) ng/l), no changes were seen in any factors of the contact system. Our study shows that in vitro endotoxin-induced activation of the contact system is a slow process that is both time and dose dependent. PMID:2463883

Roeise, O; Bouma, B N; Stadaas, J O; Aasen, A O



Thermographic variation of the udder of dairy ewes in early lactation and following an Escherichia coli endotoxin intramammary challenge in late lactation.  


A total of 83 lactating dairy ewes (Manchega, n=48; Lacaune, n=35) were used in 2 consecutive experiments for assessing the ability of infrared thermography (IRT) to detect intramammary infections (IMI) by measuring udder skin temperatures (UST). In experiment 1, ewes were milked twice daily and IRT pictures of the udder were taken before and after milking at 46 and 56d in milk (DIM). Milk yield was 1.46 ± 0.04 L/d, on average. Detection of IMI was done using standard bacterial culture by udder half at 15, 34, and 64 DIM. Twenty-two ewes were classified as having IMI in at least one udder half, the others being healthy (142 healthy and 24 IMI halves, respectively). Four IMI halves had clinical mastitis. No UST differences were detected by IMI and udder side, being 32.94 ± 0.04°C on average. Nevertheless, differences in UST were detected for breed (Lacaune - Manchega=0.35 ± 0.08°C), milking process moment (after - before=0.13 ± 0.11°C), and milking schedule (p.m. - a.m.=0.79 ± 0.07°C). The UST increased linearly with ambient temperature (r=0.88). In experiment 2, the UST response to an Escherichia coli O55:B5 endotoxin challenge (5 ?g/udder half) was studied in 9 healthy Lacaune ewes milked once daily in late lactation (0.58 ± 0.03 L/d; 155 ± 26 DIM). Ewes were allocated into 3 balanced groups of 3 ewes to which treatments were applied by udder half after milking. Treatments were (1) control (C00, both udder halves untreated), (2) half udder treated (T10 and C01, one udder half infused with endotoxin and the other untreated, respectively), and (3) treated udder halves (T11, both udder halves infused with endotoxin). Body (vaginal) temperature and UST, milk yield, and milk composition changes were monitored by udder half at different time intervals (2 to 72 h). First local and systemic signs of IMI were observed at 4 and 6h postchallenge, respectively. For all treatments, UST increased after the challenge, peaking at 6h in T 0055 (which differed from that in C00, C01, and T10), and decreased thereafter without differences by treatment. Vaginal temperature and milk somatic cell count increased by 6h postchallenge, whereas lactose content decreased, in the endotoxin-infused udder halves. Effects of endotoxin on lactose and somatic cell count values were detectable in the infused udder halves until 72 h. In conclusion, despite the accuracy of the camera (± 0.15°C) and the moderate standard errors of the mean obtained for UST measures (± 0.05 to 0.24°C), we were unable to discriminate between healthy and infected (subclinically or clinically) udder halves in dairy ewes. PMID:24418270

Castro-Costa, A; Caja, G; Salama, A A K; Rovai, M; Flores, C; Aguiló, J



Metabolic and endocrine changes in response to endotoxin administration with or without oral arginine supplementation.  


This study was performed to investigate blood metabolite, tumor necrosis factor-alpha, and hormone responses to intravenous administration of lipopolysaccharides (2 microg of endotoxin of Escherichia coli 026:B6/kg body weight at times of feeding) in veal calves orally supplemented with arginine (0.25 g/kg of body weight twice daily for 4 d; group GrA) compared with calves not supplemented with arginine (group GrC). Arginine supplementation alone caused a significant rise of plasma arginine, urea, and insulin concentrations, whereas glucagon concentrations tended to increase, but there were no significant group differences. Concentrations of triglycerides, NEFA, glucose, protein, albumin, growth hormone, insulin-like growth factor-I, 3.5.3'-triiodothyronine, and thyroxine were not affected by arginine supplementation. Lipopolysaccharide administration alone caused a rise of tumor necrosis-factor-a, lactate, and cortisol concentrations and concentrations of tumor necrosis-factor-a after 1 h, and of triglycerides and urea after 6 h were higher, whereas of glucose after 3 h were lower in GrA than in GrC. Concentrations of NEFA, glucose, protein, albumin, insulin, growth hormone, insulin-like growth factor-I, 3.5.3'-triiodothyronine, and thyroxine were not affected by lipopolysaccharide administration. In conclusion, arginine supplementation had selective effects on plasma metabolites and hormones, but barely modified lipopolysaccharide effects. Effects of lipopolysaccharides in the postprandial state were different from what is usually seen in the fasted state. PMID:12214985

Hüsier, B R; Blum, J W



The Lipopolysaccharide Export Pathway in Escherichia coli: Structure, Organization and Regulated Assembly of the Lpt Machinery  

PubMed Central

The bacterial outer membrane (OM) is a peculiar biological structure with a unique composition that contributes significantly to the fitness of Gram-negative bacteria in hostile environments. OM components are all synthesized in the cytosol and must, then, be transported efficiently across three compartments to the cell surface. Lipopolysaccharide (LPS) is a unique glycolipid that paves the outer leaflet of the OM. Transport of this complex molecule poses several problems to the cells due to its amphipatic nature. In this review, the multiprotein machinery devoted to LPS transport to the OM is discussed together with the challenges associated with this process and the solutions that cells have evolved to address the problem of LPS biogenesis. PMID:24549203

Polissi, Alessandra; Sperandeo, Paola



Endotoxin removal by radio frequency gas plasma (glow discharge)  

NASA Astrophysics Data System (ADS)

Contaminants remaining on implantable medical devices, even following sterilization, include dangerous fever-causing residues of the outer lipopolysaccharide-rich membranes of Gram-negative bacteria such as the common gut microorganism E. coli. The conventional method for endotoxin removal is by Food & Drug Administration (FDA)-recommended dry-heat depyrogenation at 250°C for at least 45 minutes, an excessively time-consuming high-temperature technique not suitable for low-melting or heat-distortable biomaterials. This investigation evaluated the mechanism by which E. coli endotoxin contamination can be eliminated from surfaces during ambient temperature single 3-minute to cumulative 15-minute exposures to radio-frequency glow discharge (RFGD)-generated residual room air plasmas activated at 0.1-0.2 torr in a 35MHz electrodeless chamber. The main analytical technique for retained pyrogenic bio-activity was the Kinetic Chromogenic Limulus Amebocyte Lysate (LAL) Assay, sufficiently sensitive to document compliance with FDA-required Endotoxin Unit (EU) titers less than 20 EU per medical device by optical detection of enzymatic color development corresponding to < 0.5 EU/ml in sterile water extracts of each device. The main analytical technique for identification of chemical compositions, amounts, and changes during sequential reference Endotoxin additions and subsequent RFGD-treatment removals from infrared (IR)-transparent germanium (Ge) prisms was Multiple Attenuated Internal Reflection (MAIR) infrared spectroscopy sensitive to even monolayer amounts of retained bio-contaminant. KimaxRTM 60 mm x 15 mm and 50mm x 15mm laboratory glass dishes and germanium internal reflection prisms were inoculated with E. coli bacterial endotoxin water suspensions at increments of 0.005, 0.05, 0.5, and 5 EU, and characterized by MAIR-IR spectroscopy of the dried residues on the Ge prisms and LAL Assay of sterile water extracts from both glass and Ge specimens. The Ge prism MAIR-IR measurements were repeated after employing 3-minute RFGD treatments sequentially for more than 10 cycles to observe removal of deposited matter that correlated with diminished EU titers. The results showed that 5 cycles, for a total exposure time of 15 minutes to low-temperature gas plasma, was sufficient to reduce endotoxin titers to below 0.05 EU/ml, and correlated with concurrent reduction of major endotoxin reference standard absorption bands at 3391 cm-1, 2887 cm-1, 1646 cm -1 1342 cm-1, and 1103 cm-1 to less than 0.05 Absorbance Units. Band depletion varied from 15% to 40% per 3-minute cycle of RFGD exposure, based on peak-to-peak analyses. In some cases, 100% of all applied biomass was removed within 5 sequential 3-minute RFGD cycles. The lipid ester absorption band expected at 1725 cm-1 was not detectable until after the first RFGD cycle, suggesting an unmasking of the actual bacterial endotoxin membrane induced within the gas plasma environment. Future work must determine the applicability of this low-temperature, quick depyrogenation process to medical devices of more complicated geometry than the flat surfaces tested here.

Poon, Angela



Interaction of Antimicrobial Peptide Temporin L with Lipopolysaccharide In Vitro and in Experimental Rat Models of Septic Shock Caused by Gram-Negative Bacteria†  

PubMed Central

Sepsis remains a major cause of morbidity and mortality in hospitalized patients, despite intense efforts to improve survival. The primary lead for septic shock results from activation of host effector cells by endotoxin, the lipopolysaccharide (LPS) associated with cell membranes of gram-negative bacteria. For these reasons, the quest for compounds with antiendotoxin properties is actively pursued. We investigated the efficacy of the amphibian skin antimicrobial peptide temporin L in binding Escherichia coli LPS in vitro and counteracting its effects in vivo. Temporin L strongly bound to purified E. coli LPS and lipid A in vitro, as proven by fluorescent displacement assay, and readily penetrated into E. coli LPS monolayers. Furthermore, the killing activity of temporin L against E. coli was progressively inhibited by increasing concentrations of LPS added to the medium, further confirming the peptide's affinity for endotoxin. Antimicrobial assays showed that temporin L interacted synergistically with the clinically used ?-lactam antibiotics piperacillin and imipenem. Therefore, we characterized the activity of temporin L when combined with imipenem and piperacillin in the prevention of lethality in two rat models of septic shock, measuring bacterial growth in blood and intra-abdominal fluid, endotoxin and tumor necrosis factor alpha (TNF-?) concentrations in plasma, and lethality. With respect to controls and single-drug treatments, the simultaneous administration of temporin L and ?-lactams produced the highest antimicrobial activities and the strongest reduction in plasma endotoxin and TNF-? levels, resulting in the highest survival rates. PMID:16801429

Giacometti, Andrea; Cirioni, Oscar; Ghiselli, Roberto; Mocchegiani, Federico; Orlando, Fiorenza; Silvestri, Carmela; Bozzi, Argante; Di Giulio, Antonio; Luzi, Carla; Mangoni, Maria Luisa; Barra, Donatella; Saba, Vittorio; Scalise, Giorgio; Rinaldi, Andrea C.



Regulation of Cocaine- and Amphetamine-Regulated Transcript-Synthesising Neurons of the Hypothalamic Paraventricular Nucleus by Endotoxin; Implications for Lipopolysaccharide-Induced Regulation of Energy Homeostasis  

PubMed Central

Infectious diseases and the administration of bacterial lipopolysaccharide (LPS) result in decreased food intake and increased energy expenditure. Because the hypothalamic paraventricular nucleus (PVN) has pivotal roles in the regulation of energy homeostasis and expresses an anorexic peptide, cocaine- and amphetamine-regulated transcript (CART), we hypothesised that increased CART synthesis in this nucleus may contribute to LPS-induced changes in energy homeostasis. Therefore, we studied the effects of intraperitoneal administration of LPS on CART gene expression in the PVN by semiquantitative in situ hybridisation. LPS caused a rapid increase in CART mRNA levels in the PVN. One hour after treatment, the density of silver grains was increased by three-fold in the PVN, and remained elevated 3 h after treatment. Because the dorsal vagal complex, an important vegetative centre in the brainstem, is heavily innervated by CART-containing axons, we determined whether the retrograde tracer, cholera toxin B subunit (CTB), accumulates in CART neurons in the PVN following stereotaxic injection of the tracer into the dorsal vagal complex. One week after injection, CTB accumulated in CART neurons in the ventral, medial, and lateral parvocellular subdivisions of the PVN. In addition, LPS administration induced c-fos expression in a population of CART neurons in the PVN that project to the dorsal vagal complex. These data indicate that increased CART gene expression in neurons of PVN may contribute to LPS-induced anorexia, and suggest that this action may be mediated, at least in part, through a PVN-dorsal vagal complex pathway. PMID:18624928

Füzesi, T.; Sánchez, E.; Wittmann, G.; Singru, P. S.; Fekete, C.; Lechan, R. M



Preparation of endotoxin-free bacteriophages.  


Bacteriophages (phages) are bacterial viruses that interact with bacterial walls and invade bacterial cells. Moreover, they disturb bacterial metabolism and lead to bacteria lysis. In the case of Gram-negative bacteria crude phage cultures, apart from the phages themselves, the bacterial debris, bacterial proteins and nucleic acids contain endotoxins. These endotoxins (lipopolysaccharides) posses a high degree of toxicity in vitro and in vivo, and their removal is essential for safety in antibacterial bacteriophage therapy. An effective, scaleable purification of bacteriophages from endotoxins was accomplished by sequential ultrafiltration through polysulfone membrane (30 nm) followed by chromatography on sepharose 4B and Matrex Cellulofine Sulfate. The phage fraction after gel filtration chromatography routinely contained endotoxins in the 150-2500 EU/ml range. The procedure yielded bacteriophages contaminated with as little as 0.4-7 EU/ml (Limulus assay). This value lies within the permitted level for intravenous applications (5 EU/kg/h by European Pharmacopoeia, 1997). PMID:15213806

Boraty?ski, Janusz; Syper, Danuta; Weber-Dabrowska, Beata; ?usiak-Szelachowska, Marzanna; Po?niak, Gryzelda; Górski, Andrzej



Structure and Functional Analysis of LptC, a Conserved Membrane Protein Involved in the Lipopolysaccharide Export Pathway in Escherichia coli*  

PubMed Central

LptC is a conserved bitopic inner membrane protein from Escherichia coli involved in the export of lipopolysaccharide from its site of synthesis in the cytoplasmic membrane to the outer membrane. LptC forms a complex with the ATP-binding cassette transporter, LptBFG, which is thought to facilitate the extraction of lipopolysaccharide from the inner membrane and release it into a translocation pathway that includes the putative periplasmic chaperone LptA. Cysteine modification experiments established that the catalytic domain of LptC is oriented toward the periplasm. The structure of the periplasmic domain is described at a resolution of 2.2-? from x-ray crystallographic data. The periplasmic domain of LptC consists of a twisted boat structure with two ?-sheets in apposition to each other. The ?-sheets contain seven and eight antiparallel ?-strands, respectively. This structure bears a high degree of resemblance to the crystal structure of LptA. Like LptA, LptC binds lipopolysaccharide in vitro. In vitro, LptA can displace lipopolysaccharide from LptC (but not vice versa), consistent with their locations and their proposed placement in a unidirectional export pathway. PMID:20720015

Tran, An X.; Dong, Changjiang; Whitfield, Chris



Biological activities of Brucella abortus lipopolysaccharides.  

PubMed Central

Purified lipopolysaccharide (LPS) from smooth (s) and rough (R) strains of Brucella abortus and lipid A isolated from S-LPS by mild acid hydrolysis were examined in several assays of biological activity. Brucella S- and R-LPSs and Brucella lipid A activated the complement cascade. Previously reported mitogenic activation by Brucella LPSs of spleen cells from endotoxin-resistant C3H/HeJ mice was confirmed and also produced by isolated Brucella lipid A. Mitogenicity was not inhibited by polymyxin B, and amino acid analysis showed no binding of polymyxin B to Brucella LPS under conditions in which mitogenicity of phenol-water-extracted Escherichia coli LPS was inhibited. S and R Brucella LPSs and lipid A all produced equivalent polyclonal stimulation of C3H/HeJ and C3H/HeAU spleen cells. Crude and purified LPS from S but not from R B. abortus was toxic for outbred mice, with 50% lethal doses approximately six times greater than that for E. coli LPS. S- and R-LPSs were abortifacient in pregnant outbred mice. S Brucella LPS was lethal for carrageenen-pretreated C3H/HeJ and C3H/HeAU mice, whereas only C3H/HeAU mice were killed by E. coli LPS. The data are consistent with the hypothesis that the unique fatty acid composition of Brucella lipid A is responsible for its biological activity in endotoxin-resistant C3H/HeJ mice. The participation of the protein strongly bound to the lipid A cannot be excluded, but its mode of action, if any, is different from that of the lipid A-associated protein of enterobacterial LPS. PMID:6783538

Moreno, E; Berman, D T; Boettcher, L A



Kinin B1 receptors mediate depression-like behavior response in stressed mice treated with systemic E. coli lipopolysaccharide  

PubMed Central

Background Kinin B1 receptors are inducible molecules up-regulated after inflammatory stimuli. This study evaluated the relevance of kinin B1 receptors in a mouse depression behavior model. Methods Mice were exposed to a 5-min swimming session, and 30 min later they were injected with E. coli lipopolysaccharide (LPS). Depression-like behavior was assessed by determining immobility time in a tail suspension test. Different brain structures were collected for molecular and immunohistochemical studies. Anhedonia was assessed by means of a sucrose intake test. Results Our protocol elicited an increase in depression-like behavior in CF1 mice, as assessed by the tail-suspension test, at 24 h. This behavior was significantly reduced by treatment with the selective B1 receptor antagonists R-715 and SSR240612. Administration of SSR240612 also prevented an increase in number of activated microglial cells in mouse hippocampus, but did not affect a reduction in expression of mRNA for brain-derived neurotrophic factor. The increased immobility time following LPS treatment was preceded by an enhancement of hippocampal and cortical B1 receptor mRNA expression (which were maximal at 1 h), and a marked production of TNF? in serum, brain and cerebrospinal fluid (between 1 and 6 h). The depression-like behavior was virtually abolished in TNF? p55 receptor-knockout mice, and increased B1 receptor mRNA expression was completely absent in this mouse strain. Furthermore, treatment with SSR240612 was also effective in preventing anhedonia in LPS-treated mice, as assessed using a sucrose preference test. Conclusion Our data show, for the first time, involvement of kinin B1 receptors in depressive behavioral responses, in a process likely associated with microglial activation and TNF? production. Thus, selective and orally active B1 receptor antagonists might well represent promising pharmacological tools for depression therapy. PMID:21194425



Frequencies of lipopolysaccharide core types in Escherichia coli strains from bacteraemic patients.  


We have investigated the distribution of the various core types (R1, R2, R3, R4 and K-12) in 138 Escherichia coli isolates obtained from positive blood cultures. Rabbit antisera, raised against five rough strains expressing the respective core types, were made monospecific by extensive absorption. The reactivity of the antisera was tested in ELISA with bacterial cells that had been autoclaved for full exposure of core epitopes. One hundred and thirty strains could be typed directly, while eight strains required prior digestion with proteinase K for removal of cross-reactions. Ninety-four of the strains (68%) expressed the R1 type, and 9 (6.5%), 12 (8.7%), 7 (5.1%) and 3 (2.2%) strains expressed the R2, R3, R4 and K-12 core types, respectively. An R1R4 mixed core type, hitherto not yet described, was found in 13 (9.4%) strains. Results obtained with polyclonal antisera were in agreement with those obtained with monoclonal antibodies to the R1, R2 and R3 core types. Core typing may serve as an additional serological marker next to conventional typing of O-, H- and K-antigens. PMID:7517766

Appelmelk, B J; An, Y Q; Hekker, T A; Thijs, L G; MacLaren, D M; de Graaf, J



Differential Regulation of Membrane CD14 Expression and Endotoxin-Tolerance in Alveolar Macrophages  

PubMed Central

SUMMARY CD14 is important in the clearance of bacterial pathogens from lungs. However, the mechanisms that regulate the expression of membrane CD14 (mCD14) on alveolar macrophages (AM) have not been studied in detail. This study examines the regulation of mCD14 on AM exposed to Escherichia coli in vivo and in vitro and explores the consequences of changes in mCD14 expression. The expression of mCD14 was decreased on AM exposed to E. coli in vivo and AM incubated with lipopolysaccharide (LPS) or E. coli in vitro. Polymyxin B abolished LPS effects but only partially blocked the effects of E. coli. Blockade of extracellular signal-regulated kinase pathways attenuated LPS and E. coli-induced decrease in mCD14 expression. Inhibition of proteases abrogated the LPS-induced decrease in mCD14 expression on AM and the release of sCD14 into the supernatants, but did not affect the response to E. coli. The production of TNF-? in response to a second challenge with Staphylococcus aureus or zymosan was decreased in AM following incubation with E. coli but not LPS. These studies show that distinct mechanisms regulate the expression of mCD14 and the induction of endotoxin-tolerance in AM and suggest that AM function is impaired at sites of bacterial infection. PMID:15059784

Lin, Shu-Min; Frevert, Charles W.; Kajikawa, Osamu; Wurfel, Mark M.; Ballman, Kimberly; Mongovin, Stephen; Wong, Venus A.; Selk, Amy; Martin, Thomas R.



Changes in Endotoxin-Binding Proteins during Major Elective Surgery: Important Role for Soluble CD14 in Regulation of Biological Activity of Systemic Endotoxin  

Microsoft Academic Search

Assessment of circulating endotoxin during the perioperative period, which is only demonstrated by the Limulus amebocyte lysate (LAL) test, may be modulated by several endotoxin-binding proteins. Endotoxin- neutralizing capacity (ENC) and the plasma levels of soluble CD14 (sCD14), lipopolysaccharide-binding protein, and bactericidal\\/permeability-increasing protein (BPI) were determined in 40 patients 6 h prior to skin incision for major abdominal surgery. The




Potent CD14-Mediated Signalling of Human Leukocytes by Escherichia coliCan Be Mediated by Interaction of Whole Bacteria and Host Cells without Extensive Prior Release of Endotoxin  

Microsoft Academic Search

How invading microorganisms are detected by the host has not been well defined. We have compared the abilities of Escherichia coli and lipopolysaccharides (LPS) purified from these bacteria to prime isolated neutrophils for phorbol myristate acetate-stimulated arachidonate release, to trigger respiratory burst in 1% blood, and to increase steady-state levels of tumor necrosis factor alpha mRNA in whole blood. In




Both Group 4 Capsule and Lipopolysaccharide O-Antigen Contribute to Enteropathogenic Escherichia coli Resistance to Human ?-Defensin 5  

PubMed Central

Enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC) are food-borne pathogens that colonize the small intestine and colon, respectively. To cause disease, these pathogens must overcome the action of different host antimicrobial peptides (AMPs) secreted into these distinct niches. We have shown previously that EHEC expresses high levels of the OmpT protease to inactivate the human cathelicidin LL-37, an AMP present in the colon. In this study, we investigate the mechanisms used by EPEC to resist human ?-defensin 5 (HD-5), the most abundant AMP in the small intestine. Quantitative PCR was used to measure transcript levels of various EPEC surface structures. High transcript levels of gfcA, a gene required for group 4 capsule (G4C) production, were observed in EPEC, but not in EHEC. The unencapsulated EPEC ?gfcA and EHEC wild-type strains were more susceptible to HD-5 than EPEC wild-type. Since the G4C is composed of the same sugar repeats as the lipopolysaccharide O-antigen, an -antigen ligase (waaL) deletion mutant was generated in EPEC to assess its role in HD-5 resistance. The ?waaL EPEC strain was more susceptible to HD-5 than both the wild-type and ?gfcA strains. The ?gfcA?waaL EPEC strain was not significantly more susceptible to HD-5 than the ?waaL strain, suggesting that the absence of -antigen influences G4C formation. To determine whether the G4C and -antigen interact with HD-5, total polysaccharide was purified from wild-type EPEC and added to the ?gfcA?waaL strain in the presence of HD-5. The addition of exogenous polysaccharide protected the susceptible strain against HD-5 killing in a dose-dependent manner, suggesting that HD-5 binds to the polysaccharides present on the surface of EPEC. Altogether, these findings indicate that EPEC relies on both the G4C and the -antigen to resist the bactericidal activity of HD-5. PMID:24324796

Thomassin, Jenny-Lee; Lee, Mark J.; Brannon, John R.; Sheppard, Donald C.; Gruenheid, Samantha; Le Moual, Hervé



Structural investigations into the interaction of hemoglobin and part structures with bacterial endotoxins  

Microsoft Academic Search

An understanding of details of the interaction mechanisms of bacterial endotoxins (lipopolysaccharide, LPS) with the oxygen transport protein hemoglobin is still lacking, despite its high biological relevance. Here, a biophysical investigation into the endotoxin:hemoglobin interaction is presented which comprises the use of various rough mutant LPS as well as free lipid A; in addition to the complete hemoglobin molecule from

Jörg Howe; Patrick Garidel; Manfred Roessle; Walter Richter; Christian Alexander; Karin Fournier; Jean Pierre Mach; Thierry Waelli; Reginald M. Gorczynski; Artur J. Ulmer; Ulrich Zähringer; Alfred Hartmann; Ernst Th. Rietschel; Klaus Brandenburg



Endotoxin, thrombin, and the Limulus amebocyte lysate test.  


The Limulus amebocyte lysate, a proteinaceous composite isolated from the hemolymph cells of the horseshoe crab (Limulus polyphemus) is sensitive to picogram quantities of Gram-negative bacterial lipopolysaccharides. However, a controversy currently exists as to whether the Limulus amebocyte lysate is specifically sensitive to Gram-negative bacterial endotoxins as a result of a recent report that the blood coagulation protease, thrombin, can mimic endotoxins in the Limulus amebocyte lysate test. Experiments including those employing two highly purified fractions isolated from the Limulus lystae have provided us with evidence that thrombin per se is unable to mimic endotoxin. PMID:1151159

Yin, E T



Properties of free endotoxin from Pasteurella multocida.  


Free endotoxin (FET) from virulent encapsulated Pasteurella multocida or from an avirulent nonencapsulated mutant is capable of inducing active immunity, but the lipopolysaccharide (LPS) moiety of the endotoxin is not. These results suggest that a protein of P multocida is involved in the stimulation of active immunity. The serologic specificity of the FET is associated with the LPS moiety, which is related to a heat extracted antigen that is used for serotyping P multocida. The FET is capable of producing widespread vascular alteration and death. It is present in the vascular system of turkeys with acute fowl cholera, and it can be detected with the "Limulus" test for endotoxins and with the gel diffusion precipitin test. PMID:1092224

Heddleston, K L; Rebers, P A



Lipid A, the lipid component of bacterial lipopolysaccharides: Relation of chemical structure to biological activity  

Microsoft Academic Search

Summary Lipopolysaccharides are integral components of the outer membrane of Gram-negative bacteria and they participate in various membrane functions essential for bacterial growth and survival. Lipopolysaccharides also represent the endotoxins of Gram-negative bacteria and possibly play a role for the pathogenesis and manifestations of bacterial infections. These biological activities are mediated mainly by the lipid component of lipopolysaccharides, termed lipid

Ernst Th. Rietschel; Horst-Werner Wollenweber; Ulrich Zähringer; Otto Lüderitz



Distribution of radiolabeled endotoxin with particular reference to the eye: concise communication  

SciTech Connect

A single systemic injection of endotoxin (lipopolysaccharide or LPS) reproducibly induces a cellular infiltrate in the uveal tract of the rat eye within 24 hr. Other organs are not comparably sensitive to systemic endotoxin. One hypothesis to explain this unique sensitivity is that endotoxin is preferentially bound by ocular tissue. Researchers tested this hypothesis by studying the distribution in the rat of intravenously injected endotoxin that had been radiolabeled with /sup 99m/Tc or /sup 32/P. With either radionuclide the concentration of endotoxin per gram of tissue at a variety of times after injection ranging from 5 min to 3 hr and 45 min, was markedly less in the eye than in liver, kidney, or spleen. A study with radiolabeled albumin indicated that these differences could not be ascribed solely to the organ's blood volume. They demonstrate, therefore, that the eye does not preferentially bind endotoxin, and they are compatible with the hypothesis that endotoxin's ocular effects are indirectly mediated.

Rosenbaum, J.T.; Hendricks, P.A.; Shively, J.E.; McDougall, I.R.



In vivo effects of Escherichia coli lipopolysaccharide on regulation of immune response and protein expression in striped catfish (Pangasianodon hypophthalmus).  


Lipolysaccharide (LPS), a component of outer membrane protein of gram-negative bacteria, reportedly stimulates fish immune system. However, mechanisms driving this immunomodulatory effect are yet unknown. To determine effects of Escherichia coli lipopolysaccharide on regulation of immune response and protein expression of striped catfish (Pangasianodon hypophthalmus), juvenile fish (20-25 g) were injected with 3, 15 or 45 mg E.coli LPS/kg and challenged with Edwardsiella ictaluri. Plasma cortisol and glucose were rather low and did not differ (p<0.05) among treatments. All LPS treatments differed regarding blood cell count and immune variables such as plasma and spleen lysozyme, complement activity and antibody titer, 3mg LPS/kg yielding best results; red blood cell count was not affected by LPS treatment. Accumulated mortalities after bacterial challenge were 23.4, 32.8, 37.7 and 52.5% for treatment 3, 15, 45 mg LPS/kg fish and control respectively. Proteomic analysis of peripheral blood mononuclear cells (PBMC) confirmed that LPS induced differentially over-expressed immune proteins such as complement component C3 and lysozyme C2 precursor. Regulation of other proteins such as Wap65, alpha-2 macroglobulin-3 and transferrin precursor was also demonstrated. Striped catfish injected with E.coli LPS enhanced innate immune responses. PMID:23207480

Hang, Bui Thi Bich; Milla, Sylvain; Gillardin, Virginie; Phuong, Nguyen Thanh; Kestemont, Patrick



A PCR Specific for Escherichia coli O157 Based on the rfb Locus Encoding O157 Lipopolysaccharide  

PubMed Central

A PCR was developed for the detection of Escherichia coli O157 based on the rfbE O-antigen synthesis genes. A 479-bp PCR product was amplified specifically from E. coli O157 in cell lysates containing 200 or 2 CFU following crude DNA extraction. The PCR detected <1 CFU of E. coli O157 per ml in raw milk following enrichment. PMID:9620428

Desmarchelier, Patricia M.; Bilge, Sima S.; Fegan, Narelle; Mills, Leanne; Vary, James C.; Tarr, Phillip I.



Hyporeactivity of mesenteric vascular bed in endotoxin-treated rats  

Microsoft Academic Search

Vascular reactivity and activation of the nitric oxide (NO) pathway were investigated in perfused mesenteric vascular bed removed from rats 5 h after i.p. injection of bacterial lipopolysaccharide (E. coli lipopolysaccharide, 30 mg kg?1). Lipopolysaccharide treatment induced hyporesponsiveness to noradrenaline. Maximal noradrenaline-induced vasoconstriction was significantly reduced in lipopolysaccharide-treated vs. untreated preparations. Continuous infusion of l-arginine (l-Arg) (0.2 mM) enhanced noradrenaline

Delia Mitolo-Chieppa; Miralma Serio; M. Assunta Potenza; Monica Montagnani; Gianfranco Mansi; Salvatore Pece; Emilio Jirillo; Jean-Claude Stoclet



Neutrophils Contribute to Endotoxin Enhancement of Allyl Alcohol Hepatotoxicity  

Microsoft Academic Search

Nontoxic doses of endotoxin (lipopolysaccharide, LPS) enhance the hepatotoxicity of many xenobiotic agents, including allyl alcohol. Systemic LPS exposure induces an inflammatory response, including accumulation and activation of neutrophils (PMNs) in the liver. The hypothesis that PMNs play a causal role in LPS enhancement of allyl alcohol hepatotoxicity was tested. Rats were pretreated with an anti-neutrophil antibody (anti-PMN immunoglobulin [lg])

Shawn Kinser; Rosie Sneed; Robert Roth; Patricia Ganey



Binding and neutralization of bacterial lipopolysaccharide by colistin nonapeptide.  


Polymyxin nonapeptides, proteolytic derivatives of polymyxin antibiotics, are less toxic than their parent compounds but retain some of their antibacterial activities. To confirm and expand observations that polymyxin nonapeptides have anti-endotoxin activity, we studied the ability of colistin nonapeptide to bind to bacterial lipopolysaccharide (LPS) and to inhibit the effects of LPS on Limulus amoebocyte lysate and lymphocyte mitogenicity. Colistin nonapeptide was purified by high-pressure liquid chromatography and was demonstrated to bind to LPS by equilibrium dialysis. The ability of colistin nonapeptide to render E. coli ATCC 25922 cells sensitive to erythromycin was abrogated by 50% after incubation with E. coli O18 LPS in a ratio by weight of LPS to colistin nonapeptide of 3.9:1. The presence of 4 micrograms of colistin nonapeptide or colistin per ml increased by 130- and 800-fold, respectively, the concentration of E. coli O113 LPS required to produce 50% gelation of Limulus amoebocyte lysate as measured by a spectrophotometric assay. Neutralization of LPS by colistin nonapeptide was time and concentration dependent. In contrast to the neutralization seen with LPS derived from a colistin-sensitive organism, colistin nonapeptide neutralized very little LPS extracted from a strain of Serratia marcescens that was resistant to colistin. Colistin nonapeptide also inhibited LPS-induced [3H]thymidine uptake by splenic lymphocytes, but its activity was less than 1/10 that of colistin. We conclude that colistin nonapeptide binds to LPS and possesses antiendotoxin activity. However, the anti-endotoxin activity of the nonapeptide is considerably less than that of its parent compound, colistin. PMID:2412488

Warren, H S; Kania, S A; Siber, G R



Neural Substrate of Cold-Seeking Behavior in Endotoxin Shock  

PubMed Central

Systemic inflammation is a leading cause of hospital death. Mild systemic inflammation is accompanied by warmth-seeking behavior (and fever), whereas severe inflammation is associated with cold-seeking behavior (and hypothermia). Both behaviors are adaptive. Which brain structures mediate which behavior is unknown. The involvement of hypothalamic structures, namely, the preoptic area (POA), paraventricular nucleus (PVH), or dorsomedial nucleus (DMH), in thermoregulatory behaviors associated with endotoxin (lipopolysaccharide [LPS])-induced systemic inflammation was studied in rats. The rats were allowed to select their thermal environment by freely moving in a thermogradient apparatus. A low intravenous dose of Escherichia coli LPS (10 µg/kg) caused warmth-seeking behavior, whereas a high, shock-inducing dose (5,000 µg/kg) caused cold-seeking behavior. Bilateral electrocoagulation of the PVH or DMH, but not of the POA, prevented this cold-seeking response. Lesioning the DMH with ibotenic acid, an excitotoxin that destroys neuronal bodies but spares fibers of passage, also prevented LPS-induced cold-seeking behavior; lesioning the PVH with ibotenate did not affect it. Lesion of no structure affected cold-seeking behavior induced by heat exposure or by pharmacological stimulation of the transient receptor potential (TRP) vanilloid-1 channel (“warmth receptor”). Nor did any lesion affect warmth-seeking behavior induced by a low dose of LPS, cold exposure, or pharmacological stimulation of the TRP melastatin-8 (“cold receptor”). We conclude that LPS-induced cold-seeking response is mediated by neuronal bodies located in the DMH and neural fibers passing through the PVH. These are the first two landmarks on the map of the circuitry of cold-seeking behavior associated with endotoxin shock. PMID:17183631

Almeida, Maria C; Steiner, Alexandre A; Branco, Luiz G S; Romanovsky, Andrej A



Influence of Sanitizers on the Lipopolysaccharide Toxicity of Escherichia coli Strains Cultivated in the Presence of Zygosaccharomyces bailii  

PubMed Central

The influence of sublethal concentrations of two sanitizers, liquid iodophor and liquid hypochlorite (LH), on the growth rates and toxicity of food-borne pathogenic Escherichia coli strains grown in the presence of spoilage yeast Zygosaccharomyces bailii was assessed. When grown in combination with Z. bailii both E. coli O113 and E. coli O26 exhibited slower growth rates, except when E. coli O113 was grown in combination with Z. bailii at 0.2% LH. The growth rate of Z. bailii was not impacted by the addition of the sanitizers or by communal growth with E. coli strains. LAL and IL-6 results indicated a decrease in toxicity of pure E. coli cultures with comparable profiles for control and sanitizer exposed samples, although the LAL assay proved to be more sensitive. Interestingly, pure cultures of Z. bailii showed increased toxicity measured by LAL and decreased toxicity measured by IL-6. LAL analysis showed a decrease in toxicity of both E. coli strains grown in combination with Z. bailii, while IL-6 analysis of the mixed cultures showed an increase in toxicity. The use of LAL for toxicity determination in a mixed culture overlooks the contribution made by spoilage yeast, thus demonstrating the importance of using the appropriate method for toxicity testing in mixed microbe environments. PMID:24977173

Mogotsi, Lerato; De Smidt, Olga; Venter, Pierre; Groenewald, Willem



The waaL gene is involved in lipopolysaccharide synthesis and plays a role on the bacterial pathogenesis of avian pathogenic Escherichia coli.  


Avian pathogenic Escherichia coli (APEC) is a Gram-negative bacterium that causes avian colibacillosis, resulting in economically devastating to poultry industries worldwide. Lipopolysaccharide (LPS) has been identified as an important virulence factor of E. coli. The waaL gene encodes O-antigen ligase, which is responsible for attaching the O-antigen to lipid A-core oligosaccharide. In this study, a mutant strain ?waaL was constructed from APEC serotype 2 strain DE17. The mutant strain showed a decreased swimming motility and resistance to complement-mediated killing but a similar growth rate in the culture, compared with its parent strain. In addition, the mutant LPS demonstrated different patterns in SDS-PAGE followed by silver staining and western blotting. Besides, the mutant strain significantly decreased its adherence and invasion abilities to DF-1 cells, compared to its parent strain DE17. Deletion of the waaL gene in DE17 reduced the bacterial virulence by 42.2-fold in ducklings, based on measurement of the median lethal dose (LD50). Additional analysis indicated that deletion of the waaL gene increased the biofilm formation ability and reduced the resistance to environmental stress. These results suggest that the waaL gene functions on the APEC LPS synthesis and bacterial pathogenesis. PMID:24970366

Han, Yue; Han, Xiangan; Wang, Shaohui; Meng, Qingmei; Zhang, Yuxi; Ding, Chan; Yu, Shengqing



Gram-Negative Bacterial Lipopolysaccharide Retention by a Positively Charged New-Generation Filter  

Microsoft Academic Search

Endotoxins are lipopolysaccharides (LPS) which constitute the main component of the outer membranes of gram-negative bacteria. Endotoxins at high doses are pathogenic molecules which act as potent activators of the immune system. Mono- cytes and macrophages, following LPS stimulation, release me- diators with powerful biological and pyrogenic activities. More- over, LPS interact with the vascular endothelium and stimulate the complement

Ilaria Bononi; Veronica Balatti; Soccorso Gaeta; Mauro Tognon



Polymyxin B-horseradish peroxidase conjugates as tools in endotoxin research.  


The peptide antibiotic Polymyxin B (PMB) binds to bacterial endotoxin (lipopolysaccharide, LPS). We prepared covalent conjugates of PMB and horseradish peroxidase (HRP) by periodation of HRP-linked oligosaccharides followed by direct condensation with PMB. In addition we prepared monoclonal antibodies (Mabs) to PMB. The PMB-HRP conjugates and anti-PMB Mabs were used to study in ELISA the binding of PMB to LPS from Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. In addition, PMB-HRP was used to quantify lipid A in ELISA, and to stain gram-negative bacteria histochemically. For the study of PMB-LPS interaction, PMB-HRP proved to be superior to the anti-PMB Mabs. PMB-HRP conjugates are useful general probes to detect or measure lipid A and LPS of various species using very simple methods and to stain bacteria, and they may obviate the need for many specific antisera. Thus, PMB-HRP conjugates are useful probes for endotoxin research. PMID:1481986

Appelmelk, B J; Su, D; Verweij-van Vught, A M; Thijs, B G; MacLaren, D M



Contrasting Ocular Effects of Local versus Systemic Endotoxin  

PubMed Central

Purpose. A marked cellular infiltrate has been observed when endotoxin (lipopolysaccharide [LPS]) is injected into the mouse eye, but systemically injected LPS does not produce a comparable effect. Several hypotheses were tested to reconcile this discordance. Methods. BALB/c mice were injected intravitreally (ivt) or intraperitoneally (ip) with Escherichia coli LPS. Uveitis was assessed by traditional and intravital microscopy. Cytokine levels in the eye, plasma, or spleen were measured by single or multiplex ELISA assays. Results. The eye's higher sensitivity was confirmed to local LPS exposure, as 250 ng ivt LPS produced a brisk leukocytic infiltrate whereas ip injection of 100 ?g LPS did not. The hypothesis was tested that the lack of a cellular infiltrate after ip LPS is explained by less induction of cytokines in the eye, but surprisingly, ip LPS resulted in comparable cytokine levels to ivt LPS. The hypothesis was disproved that the eye's sensitivity to local LPS is due to lack of expression of intracellular inhibitors of LPS such as A20, IRAK-M, or SARM. Finally, the hypothesis that systemic LPS inhibits diapedesis was tested by injection of LPS ip and ivt simultaneously, a strategy that did not significantly reduce leukocyte rolling or sticking in iris vessels but blocked the cellular infiltrate normally seen with ivt LPS. Conclusions. Systemic and local LPS exposures produce discordant effects within the murine eye. The hypothesis that systemic LPS desensitizes leukocytes to the stimuli responsible for transmigration offers a plausible explanation for this discordance. PMID:21757585

Woods, April; Kezic, Jelena; Planck, Stephen R.; Rosenzweig, Holly L.



Hypoferremia in Mice and Its Application to the Bioassay of Endotoxin  

PubMed Central

Baker, Phillip J. (University of Wisconsin, Madison), and J. B. Wilson. Hypoferremia in mice and its application to the bioassay of endotoxin. J. Bacteriol. 90:903–910. 1965.—The ability of endotoxin to induce hypoferremia in mice was used for the bioassay of endotoxin. A marked depression in the serum-iron levels of mice occurred 12 hr after the intraperitoneal injection of 0.01 to 100 ?g of Escherichia coli endotoxin; similar results were obtained with 1.0 to 100 ?g of Brucella abortus endotoxin. This biological response to endotoxin appeared to be specific, reproducible, and dose-dependent. As heat-killed cells of B. abortus and E. coli were also able to induce hypoferremia, this bioassay could be employed for the determination of the endotoxin content of killed-cell preparations. Treatment of endotoxin by acid hydrolysis, acetylation, or pyridine-formic acid greatly diminished the hypoferremic response as well as its lethality for mice. Pretreatment of mice with Thorotrast had little effect upon the ability of endotoxin to induce hypoferremia; however, a stimulation of the activity of the reticuloendothelial system (RES) by treatment of mice with triolein markedly reduced the ability of endotoxin to induce hypoferremia. The relationship between the hypoferremic response to endotoxin and alterations in the activity of the RES are discussed. PMID:4954519

Baker, Phillip J.; Wilson, J. B.



Class B scavenger receptors SR-BI/BII and CD36 mediate bacterial recognition and pro-inflammatory signaling induced by E. coli, lipopolysaccharide and cytosolic chaperonin 601  

PubMed Central

Class B scavenger receptors (SR-B3) are lipoprotein receptors which also mediate pathogen recognition, phagocytosis and clearance as well as pathogen-induced signaling. In this study we report that three members of the SR-B family namely, CLA-1, CLA-2 and CD36, mediate recognition of bacteria not only through interaction with cell wall lipopolysaccharide (LPS) but also with cytosolic chaperonin 60. HeLa cells stably transfected with any of these SR-Bs demonstrated markedly (3-5-fold) increased binding and endocytosis of E. coli, LPS and chaperonin 60 (GroEL) as revealed by both FACS analysis and confocal microscopy imaging. Increased pathogen (E. coli, LPS and GroEL) binding to SR-Bs was also associated with the dose-dependent stimulation of cytokine secretion in the order of CD36>CLA-2>CLA-1 in HEK293 cells. Pathogen-induced IL-6-secretion was reduced in macrophages from CD36- and SR-BI/II-null mice by 40-50% and 30-40%, respectively. Intravenous GroEL administration increased plasma IL-6 and CXCL1 levels in mice. The cytokine responses were 40-60% lower in CD36?/? relative to WT mice, whereas, increased cytokine responses were found in SR-BI/II?/? mice. While investigating the discrepancy of in vitro vs. in vivo data in SR-BI/II-deficiency, SR-BI/II?/? mice were found to respond to GroEL administration without increases in either plasma corticosterone or aldosterone as normally seen in WT mice. SR-BI/II?/? mice with mineralocorticoid replacement demonstrated a ~40-50% reduction in CXCL1 and IL-6 responses. These results demonstrate that, by recognizing and mediating inflammatory signaling of both bacterial cell wall LPS and cytosolic GroEL, all three SR-B family members play important roles in innate immunity and host defense. PMID:22205027

Baranova, Irina N.; Vishnyakova, Tatyana G.; Bocharov, Alexander V.; Leelahavanichkul, Asada; Kurlander, Roger; Chen, Zhigang; Souza, Ana C. P.; Yuen, Peter S. T.; Star, Robert A.; Csako, Gyorgy; Patterson, Amy P.; Eggerman, Thomas L.



GM1 and GD1a gangliosides modulate toxic and inflammatory effects of E. coli lipopolysaccharide by preventing TLR4 translocation into lipid rafts.  


Exogenous gangliosides are known to inhibit the effects of Escherichia coli lipopolysaccharide (LPS) in different cells exhibiting a nti-inflammatory and immunosuppressive activities. The mechanisms underlying ganglioside action are not fully understood. Because LPS recognition and receptor complex formation occur in lipid rafts, and gangliosides play a key role in their maintenance, we hypothesize that protective effects of exogenous gangliosides would depend on inhibition of LPS signaling via prevention of TLR4 translocation into lipid rafts. The effect of GM1 and GD1a gangliosides on LPS-induced toxic and inflammatory reactions in PC12 cells, and in epithelial cells isolated from the frog urinary bladder, was studied. In PC12 cells, GD1a and GM1 significantly reduced the effect of LPS on the decrease of cell survival and on stimulation of reactive oxygen species production. In epithelial cells, gangliosides decreased LPS-stimulated iNOS expression, NO, and PGE2 production. Subcellular fractionation, in combination with immunoblotting, showed that pretreatment of cells with GM1, GD1a, or methyl-?-cyclodextrin, completely eliminated the effect of LPS on translocation of TLR4 into lipid rafts. The results are consistent with the hypothesis that ganglioside-induced prevention of TLR4 translocation into lipid rafts could be a mechanism of protection against LPS in various cells. PMID:25499607

Nikolaeva, Svetlana; Bayunova, Lubov; Sokolova, Tatyana; Vlasova, Yulia; Bachteeva, Vera; Avrova, Natalia; Parnova, Rimma



Lipopolysaccharide-induced experimental immune activation does not impair memory functions in humans.  


Systemic immune activation occurring together with release of peripheral cytokines can affect behavior and the functioning of the central nervous system (CNS). However, it remains unknown whether and to what extent cognitive functions like memory and attention are affected during transient immune activation. We employed a human endotoxemia model and standardized neuropsychological tests to assess the cognitive effects of an experimental inflammation in two groups of 12 healthy young men before and after intravenous injection of lipopolysaccharide (LPS, Escherichia coli, 0.4 ng/kg) or physiological saline. Endotoxin administration caused a profound transient physiological response with elevations in body temperature, number of circulating neutrophils, and increases in plasma cytokine levels [interleukin (IL)-6, IL-10, tumor necrosis factor (TNF)-?], and concentrations of norepinephrine, ACTH and cortisol. However, these changes in immune and neuroendocrine parameters were not associated with alterations of memory performance, selective attention or executive functions. PMID:20875866

Grigoleit, Jan-Sebastian; Oberbeck, J Reiner; Lichte, Philipp; Kobbe, Philipp; Wolf, Oliver T; Montag, Thomas; del Rey, Adriana; Gizewski, Elke R; Engler, Harald; Schedlowski, Manfred



Recombinant human bactericidal/permeability-increasing protein (rBPI23) is a universal lipopolysaccharide-binding ligand.  


A recombinant 23-kDa protein (rBPI23) derived from human bactericidal/permeability-increasing protein (BPI) possesses potent endotoxin-neutralizing abilities in vitro and in vivo. Binding of rBPI23 to those endotoxins (lipopolysaccharides [LPSs]) encountered clinically would be a prerequisite for efficacy in decreasing mortality among patients suffering from gram-negative sepsis and shock, a disease state in which an etiological role for LPS has been implicated. rBPI23 binds well to lipid A (n = 7), to rough-mutant O-chain-deficient LPS (n = 18, Re to Ra chemotypes), to lipid A-core covalently linked to the O chain, to LPSs from clinically relevant serotypes (n = 100), and to bacterial cells (n = 88) of Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae, the species most often implicated in clinical gram-negative sepsis and shock. Significant binding of rBPI23 to these antigens took place at rBPI23 concentrations of 1 to 500 ng/ml (median, 16 to 32 ng/ml). Binding did not involve 3-deoxy-D-manno-octulosonate of the inner core. Determining the exact epitope recognized by rBPI23 would require further studies with synthetic lipid A substructures. The demonstrated ability of rBPI23 to universally bind LPS provides a sound basis for further testing of its endotoxin-neutralizing abilities, including clinical trials. PMID:8039930

Appelmelk, B J; An, Y Q; Thijs, B G; MacLaren, D M; de Graaff, J



Kinetics of nitric oxide synthase induction by Propionibacterium adidum and lipopolysaccharide  

Microsoft Academic Search

Conditions for the induction of rat liver Ca2+-independent nitric oxide synthase were determined with killed Propionibacterium avidum, and compared with lipopolysaccharide endotoxin. Similar maximal induction was obtained intraperitoneally with the two types of inducers but killed Propionibacterium avidum gave a long-lasting induction while lipopolysaccharide displayed a rapid and short response. Moreover, the induction resulting from an intravenous administration of killed

Mounir Dhouib; Jean-Louis Gendrault; Alain-André Lugnier



Exacerbation of toxic effects by endotoxin contamination of recombinant human tumor necrosis factor  

Microsoft Academic Search

The toxic effects of endotoxin-free human recombinant tumor necrosis factor (rH-TNF), shown to contain E. Coli. Salmonella abortus equi, or Serratia marcescens reduced the apparent mean lethal dose of rH-TNF in correspondence to the endotoxin concentration, with a value of 0.7 mg\\/kg rH-TNF observed at 1600 ng, 757 ng, and 5260 ng endotoxin\\/mg rH-TNF, respectively. Coadministration also resulted in more

Yukio Ozaki; Toshio Oyama; Shoji Kume I



Release of endotoxin from bacteria exposed to ciprofloxacin and its prevention with polymyxin B  

Microsoft Academic Search

An in vitro system for studying the phenomenon of antibiotic-induced release of endotoxin from gram-negative bacteria is described. Endotoxin was measured by a quantitative limulus lysate microassay. Using a strain ofEscherichia coli,ciprofloxacin was shown to cause an immediate and sustained increase in endotoxin release compared to control cultures whereas gentamicin did not, despite an equally rapid bactericidal effect. The potential

J. Cohen; J. S. McConnell



Neutralization of Endotoxin In Vitro and In Vivo by a Human Lactoferrin-Derived Peptide  

Microsoft Academic Search

Endotoxin (lipopolysaccharide (LPS)) is the major pathogenic factor of gram-negative septic shock, and endo- toxin-induced death is associated with the host overproduction of tumor necrosis factor alpha (TNF-a). In the search for new antiendotoxin molecules, we studied the endotoxin-neutralizing capacity of a human lactoferrin- derived 33-mer synthetic peptide (GRRRRSVQWCAVSQPEATKCFQWQRNMRKVRGP; designated LF-33) representing the minimal sequence for lactoferrin binding to glycosaminoglycans.




Potentiation of lung vascular response to endotoxin by superoxide dismutase.  


We studied the effects of superoxide dismutase (SOD), an enzyme that converts superoxide into peroxide, on the cardiopulmonary response to endotoxin in sheep. Sheep (n = 18) were prepared for chronic measurement of cardiopulmonary variables, including lung lymph flow, by surgically implanting catheters under halothane anesthesia. Nine of the animals were studied before and after the administration of endotoxin (0.75 microgram/kg) with and without SOD. An additional nine animals received SOD without the lipopolysaccharide. Endotoxin produced an increase in lung lymph flow that was initially associated with a marked pulmonary arterial (PA) hypertension and reduced lymph-to-plasma protein ratio (L/P). The lymph flow remained elevated later in the response, but there was only a mild increase in PA pressure, and the L/P was normal. There was also a fall in blood neutrophils and in cardiac index. SOD increased this secondary elevation in lung lymph flow, and the corresponding L/P was greater than the preendotoxin value. The fall in neutrophil count, cardiac output, and the elevation in PA pressure seen with endotoxin were not affected by SOD. When administered in the absence of endotoxin, SOD produced no perceptible change in the cardiopulmonary and lymph values. We conclude that peroxide, hydroxyl ion, and/or other free radicals formed by the action of SOD must be responsible for a portion of the endotoxin response rather than superoxide itself. PMID:3980370

Traber, D L; Adams, T; Sziebert, L; Stein, M; Traber, L



The release and detection of endotoxin from liposomes.  


Incorporation of lipopolysaccharide (LPS) into liposomes dramatically reduces its ability to coagulate Limulus amebocyte lysate (LAL). The coagulation of LAL is commonly used to signal the presence of endotoxin in vitro. This study demonstrates a simple method to release masked endotoxin from liposomal dispersions using moderate amounts of detergent to form mixed micelles containing lipid, detergent, and LPS. Several parameters were found to affect the degree of liposome solubilization and/or the sensitivity of the LAL assay. These included detergent type and concentration, temperature for solubilization, lipid composition, liposome morphology, and time for test incubation. The nonionic detergent polyoxyethylene 10 lauryl ether (C12E10) proved to be unique in its ability to solubilize liposomes and minimally interfere with endotoxin detection. The LAL endotoxin detection limit for samples dispersed in C12E10 varied with the phospholipid component; the sensitivity decreased in the order DSPC > DPPC = EPC > DMPC. Cholesterol lowered the solubility limit of the liposomes, but did not appear to affect the LAL assay sensitivity once the liposomes were completely solubilized. The presence of negatively charged phospholipids, DSPG and Pops, also lowered the solubility limit. Pops, but not DSPG, at 10 mol% further decreased the LAL endotoxin detection limit. This detergent-solubilization method should be useful in liposomal LPS immunological studies or in other situations where accurate determination of endotoxin concentration is important. PMID:9245430

Harmon, P; Cabral-Lilly, D; Reed, R A; Maurio, F P; Franklin, J C; Janoff, A



Effect of Lead Acetate on the Susceptibility of Rats to Bacterial Endotoxins  

PubMed Central

Selye, H. (Université de Montréal, Montreal, Canada), B. Tuchweber, and L. Bertók. Effect of lead acetate on susceptibility of rats to bacterial endotoxins. J. Bacteriol. 91:884–890. 1966.—A single, normally well-tolerated, intravenous injection of lead acetate increases the sensitivity of the rat to the endotoxins of various gram-negative bacteria about 100,000 times above normal. Under the conditions of these experiments, the mortality and organ changes normally produced by the intravenous injection of 100 ?g of Escherichia coli endotoxin were essentially the same as those obtained by use of 1 nanogram in lead-sensitized rats. The sensitizing effect of lead acetate for E. coli endotoxin is greatest when the two agents are given simultaneously. However, considerable sensitization is still detectable when endotoxin is injected up to 1 hr before or 7 hr after sensitization with lead. No sensitization was noted when the endotoxin was administered 24 hr before or after lead acetate. Under our experimental conditions, the minimal dose of lead acetate which could still induce significant sensitization to E. coli endotoxin was 1 mg per 100 g of body weight. Although lead acetate induces a high degree of susceptibility to various endotoxins, other reticuloendothelial blocking agents did not acquire unusual toxicity after pretreatment with lead. Finally, none of the other metals or reticuloendothelial blocking agents tested could duplicate the pronounced decrease in endotoxin resistance induced by lead acetate. Images PMID:5327235

Selye, H.; Tuchweber, B.; Bertok, L.



Endotoxin aggression in the pathogenesis of chronic inflammatory diseases of small pelvis organs and infertility, or an antiendotoxin approach to their treatment  

Microsoft Academic Search

Endotoxin aggression is involved in the pathogenesis of chronic inflammatory gynecological diseases and primary and secondary\\u000a female infertility. A significant (13-to 15-fold) increase in the lipopolysaccharide concentration in the blood serum is not\\u000a associated with a rise in the body temperature or an increase in the titers of antibodies against Re glycolipid, which suggests\\u000a chronic endotoxin aggression and endotoxin tolerance.

G. G. Enukidze; I. A. Anikhovskaya; A. A. Marachev; M. Yu. Yakovlev



Polaprezinc Protects Mice against Endotoxin Shock  

PubMed Central

Polaprezinc (PZ), a chelate compound consisting of zinc and l-carnosine (Car), is an anti-ulcer drug developed in Japan. In the present study, we investigated whether PZ suppresses mortality, pulmonary inflammation, and plasma nitric oxide (NO) and tumor necrosis factor (TNF)-? levels in endotoxin shock mice after peritoneal injection of lipopolysaccharide (LPS), and how PZ protects against LPS-induced endotoxin shock. PZ pretreatment inhibited the decrease in the survival rate of mice after LPS injection. PZ inhibited the increases in plasma NO as well as TNF-? after LPS. Compatibly, PZ suppressed LPS-induced inducible NO synthase mRNA transcription in the mouse lungs. PZ also improved LPS-induced lung injury. However, PZ did not enhance the induction of heat shock protein (HSP) 70 in the mouse lungs after LPS. Pretreatment of RAW264 cells with PZ suppressed the production of NO and TNF-? after LPS addition. This inhibition likely resulted from the inhibitory effect of PZ on LPS-mediated nuclear factor-?B (NF-?B) activation. Zinc sulfate, but not Car, suppressed NO production after LPS. These results indicate that PZ, in particular its zinc subcomponent, inhibits LPS-induced endotoxin shock via the inhibition of NF-?B activation and subsequent induction of proinflammatory products such as NO and TNF-?, but not HSP induction. PMID:20490319

Ohata, Shuzo; Moriyama, Chihiro; Yamashita, Atsushi; Nishida, Tadashi; Kusumoto, Chiaki; Mochida, Shinsuke; Minami, Yukari; Nakada, Junya; Shomori, Kohei; Inagaki, Yoshimi; Ohta, Yoshiji; Matsura, Tatsuya



Polaprezinc Protects Mice against Endotoxin Shock.  


Polaprezinc (PZ), a chelate compound consisting of zinc and l-carnosine (Car), is an anti-ulcer drug developed in Japan. In the present study, we investigated whether PZ suppresses mortality, pulmonary inflammation, and plasma nitric oxide (NO) and tumor necrosis factor (TNF)-alpha levels in endotoxin shock mice after peritoneal injection of lipopolysaccharide (LPS), and how PZ protects against LPS-induced endotoxin shock. PZ pretreatment inhibited the decrease in the survival rate of mice after LPS injection. PZ inhibited the increases in plasma NO as well as TNF-alpha after LPS. Compatibly, PZ suppressed LPS-induced inducible NO synthase mRNA transcription in the mouse lungs. PZ also improved LPS-induced lung injury. However, PZ did not enhance the induction of heat shock protein (HSP) 70 in the mouse lungs after LPS. Pretreatment of RAW264 cells with PZ suppressed the production of NO and TNF-alpha after LPS addition. This inhibition likely resulted from the inhibitory effect of PZ on LPS-mediated nuclear factor-kappaB (NF-kappaB) activation. Zinc sulfate, but not Car, suppressed NO production after LPS. These results indicate that PZ, in particular its zinc subcomponent, inhibits LPS-induced endotoxin shock via the inhibition of NF-kappaB activation and subsequent induction of proinflammatory products such as NO and TNF-alpha, but not HSP induction. PMID:20490319

Ohata, Shuzo; Moriyama, Chihiro; Yamashita, Atsushi; Nishida, Tadashi; Kusumoto, Chiaki; Mochida, Shinsuke; Minami, Yukari; Nakada, Junya; Shomori, Kohei; Inagaki, Yoshimi; Ohta, Yoshiji; Matsura, Tatsuya



Statistical optimization of medium composition and culture condition for the production of recombinant anti-lipopolysaccharide factor of Eriocheir sinensis in Escherichia coli  

NASA Astrophysics Data System (ADS)

Anti-lipopolysaccharide factors (ALFs) are important antimicrobial peptides that are isolated from some aquatic species. In a previous study, we isolated ALF genes from Chinese mitten crab, Eriocheir sinensis. In this study, we optimized the production of a recombinant ALF by expressing E. sinensis ALF genes in Escherichia coli maintained in shake-flasks. In particular, we focused on optimization of both the medium composition and the culture condition. Various medium components were analyzed by the Plackett-Burman design, and two significant screened factors, (NH4)2SO4 and KH2PO4, were further optimized via the central composite design (CCD). Based on the CCD analysis, we investigated the induction start-up time, the isopropylthio-D-galactoside (IPTG) concentration, the post-induction time, and the temperature by response surface methodology. We found that the highest level of ALF fusion protein was achieved in the medium containing 1.89 g/L (NH4)2SO4 and 3.18 g/L KH2PO4, with a cell optical density of 0.8 at 600 nm before induction, an IPTG concentration of 0.5 mmol/L, a post-induction temperature of 32.7°C, and a post-induction time of 4 h. Applying the whole optimization strategy using all optimal factors improved the target protein content from 6.1% (without optimization) to 13.2%. We further applied the optimized medium and conditions in high cell density cultivation, and determined that the soluble target protein constituted 10.5% of the total protein. Our identification of the economic medium composition, optimal culture conditions, and details of the fermentation process should facilitate the potential application of ALF for further research.

Jiang, Shan; Liu, Mei; Wang, Baojie; Jiang, Keyong; Wang, Lei



Effect of crude lipopolysaccharide from Escherichia coli O127:B8 on the amebocyte-producing organ of Biomphalaria glabrata (Mollusca).  


Lipopolysaccharide (LPS) is a pathogen associated molecular pattern (PAMP) to which the internal defense system (IDS) of both vertebrates and invertebrates responds. We measured the mitotic response of the hematopoietic tissue of the schistosome-transmitting snail, Biomphalaria glabrata, to crude LPS from Escherichia coli 0127:B8. In a dose-response study, snails were injected with a range of concentrations of crude LPS, and mitotic figures were enumerated in histological sections of amebocyte-producing organ (APO) fixed at 24h post-injection (PI) following a 6h treatment with 0.1% colchicine. In APOs from Salvador strain snails, which are genetically resistant to infection with Schistosoma mansoni, LPS concentrations of 0.01 mg/ml and above triggered a large increase in mitotic activity, whereas in APOs from schistosome-susceptible NIH albino snails, concentrations of 0.1mg/ml elicited a much smaller, but statistically significant increase. A time course study, without colchicine treatment, revealed that in Salvador APOs the mitotic response to 0.1mg/ml occurred by 18 h PI, peaked at 24h, and returned to control levels by 72 h; NIH albino APOs showed no detectible response. When Salvador APOs were exposed to crude LPS in vitro, no increase in mitotic activity occurred, a result suggesting the possible requirement for a peripheral tissue or hemolymph factor. The increased cell proliferation induced by crude LPS represents a novel systemic response of an invertebrate IDS to one or more PAMPs from a Gram-negative bacterium. PMID:21530581

Sullivan, John T; Bulman, Christina A; Salamat, Zahra



Effects of Lactobacillus acidophilus dietary supplementation on the performance, intestinal barrier function, rectal microflora and serum immune function in weaned piglets challenged with Escherichia coli lipopolysaccharide.  


This study was conducted with a lipopolysaccharide (LPS)-challenged piglet model to determine the effects of diets containing Lactobacillus acidophilus on the performance, intestinal barrier function, rectal microflora and serum immune function. A total of 150 piglets (initial body weight (BW) 7.53 ± 0.21 kg) were allotted to one of the following diets, including a basal diet, a basal diet supplemented with 250 mg/kg Flavomycin, or basal diet plus 0.05, 0.1 or 0.2 % L. acidophilus. On day 28 of the trial, the pigs were given an intraperitoneal injection of LPS (200 ?g/kg body weight) followed by blood collection 3 h later. Diets with either antibiotics, 0.1 or 0.2 % Lactobacillus increased (P < 0.05) the final BW and decreased (P < 0.05) feed gain ratio (F/G) compared with the control group. Pigs fed diets containing antibiotic or Lactobacillus had greater average daily gain (ADG) (P < 0.05) than pigs fed the control diet. The rectal content Lactobacillus counts for pigs fed diet containing Lactobacillus were significant higher (P < 0.01) than those fed antibiotic or control diet. Feeding the Lactobacillus diets decreased the Escherichia coli counts of rectal content (P < 0.01). Pigs fed diets containing 0.1 or 0.2 % Lactobacillus decreased serum DAO activity (P < 0.05) compared with pigs fed the control diet. Serum IL-10 concentration was enhanced in pigs fed the diet with Lactobacillus compared to pigs fed the control diet and antibiotic diet. Feeding a diet with Lactobacillus reduced (P < 0.05) IFN-? concentration compared to the control diet. Inclusion of Lactobacillus in diets fed to pigs reduced TNF-? concentration compared with pigs fed no Lactobacillus (P < 0.05). These results indicate that feeding with L. acidophilus improved growth performance and protected against LPS-induced inflammatory status. PMID:25577203

Qiao, Jiayun; Li, Haihua; Wang, Zhixiang; Wang, Wenjie



Elevated Carbon Monoxide to Carbon Dioxide Ratio in the Exhaled Breath of Mice Treated With a Single Dose of Lipopolysaccharide  

PubMed Central

Background ?Analysis of volatile organic chemicals in breath holds promise for noninvasive diagnosis and monitoring of patients, but investigation of this in experimental mouse models has been limited. Of particular interest is endogenous production of carbon monoxide as a biomarker of inflammation and, more particularly, during sepsis. Methods ?Using a nose-only collection procedure for unanesthetized individual adult mice and sensitive gas chromatography of carbon monoxide (CO) and carbon dioxide (CO2) of sampled breath, we investigated the responses of mice to one-time injections with different doses of purified Escherichia coli lipopolysaccharide. Two strains of mice were examined: BALB/c and C3H, including an endotoxin-resistant mutant (HeJ) as well as the wild type (HOuJ). Results ?The CO to CO2 ratio increased in a dose-responsive manner within hours in treated BALC/c mice but not control mice. The CO/CO2 values declined to the range of control mice within 48–72 h after the injection of lipopolysaccharide. Breath CO/CO2 values correlated with systemic inflammation biomarkers in serum and heme oxygenase-1 gene expression in blood. C3H/HOuJ mice, but not the HeJ mice, had similar increases of the CO/CO2 ratio in response to the endotoxin. Conclusions ?Carbon monoxide concentrations in exhaled breath of at least 2 strains of mice increase in response to single injections of endotoxin. The magnitude of increase was similar to what was observed with a bacteremia model. These findings with an experimental model provide a rationale for further studies of normalized CO concentrations in human breath as an informative biomarker for staging and monitoring of sepsis. PMID:25734151

Langeroudi, Arash Ghalyanchi; Hirsch, Charlotte M.; Estabragh, Azadeh Shojaee; Meinardi, Simone; Blake, Donald R.; Barbour, Alan G.



Inhibition of endotoxin-induced bacterial translocation in mice.  

PubMed Central

The primary functions of the gut are to absorb nutrients and exclude bacteria and their products. However, under certain circumstances the gut may lose its barrier function and serve as a reservoir for systemic microbial infections. These experiments were performed to determine the mechanisms whereby endotoxin causes bacteria to escape (translocate) from the gut. Bacteria translocated from the gut to the mesenteric lymph nodes of mice challenged with nonlethal doses of Escherichia coli 026:B6 or E. coli 0111:B4 endotoxin. Physical disruption of the gut mucosal barrier appears to be the primary mechanism whereby endotoxin promotes bacterial translocation. Mucosal injury and endotoxin-induced bacterial translocation were reduced by inhibition (allopurinol) or inactivation (tung-sten diet) of xanthine oxidase activity (P less than 0.01), but were not affected by the platelet-activation factor antagonists, SRI 63-441 or BN 52021. Because the inhibition or inactivation of xanthine oxidase activity reduced both the extent of mucosal injury and endotoxin-induced bacterial translocation, the effect of endotoxin on the gut appears to be mediated, at least to some degree, by xanthine oxidase-generated, oxygen-free radicals. Images PMID:2661590

Deitch, E A; Ma, L; Ma, W J; Grisham, M B; Granger, D N; Specian, R D; Berg, R D



Vagus nerve stimulation attenuates the systemic inflammatory response to endotoxin  

NASA Astrophysics Data System (ADS)

Vertebrates achieve internal homeostasis during infection or injury by balancing the activities of proinflammatory and anti-inflammatory pathways. Endotoxin (lipopolysaccharide), produced by all gram-negative bacteria, activates macrophages to release cytokines that are potentially lethal. The central nervous system regulates systemic inflammatory responses to endotoxin through humoral mechanisms. Activation of afferent vagus nerve fibres by endotoxin or cytokines stimulates hypothalamic-pituitary-adrenal anti-inflammatory responses. However, comparatively little is known about the role of efferent vagus nerve signalling in modulating inflammation. Here, we describe a previously unrecognized, parasympathetic anti-inflammatory pathway by which the brain modulates systemic inflammatory responses to endotoxin. Acetylcholine, the principle vagal neurotransmitter, significantly attenuated the release of cytokines (tumour necrosis factor (TNF), interleukin (IL)-1?, IL-6 and IL-18), but not the anti-inflammatory cytokine IL-10, in lipopolysaccharide-stimulated human macrophage cultures. Direct electrical stimulation of the peripheral vagus nerve in vivo during lethal endotoxaemia in rats inhibited TNF synthesis in liver, attenuated peak serum TNF amounts, and prevented the development of shock.

Borovikova, Lyudmila V.; Ivanova, Svetlana; Zhang, Minghuang; Yang, Huan; Botchkina, Galina I.; Watkins, Linda R.; Wang, Haichao; Abumrad, Naji; Eaton, John W.; Tracey, Kevin J.



Kinetics of Hydrothermal Inactivation of Endotoxins ?  

PubMed Central

A kinetic model was established for the inactivation of endotoxins in water at temperatures ranging from 210°C to 270°C and a pressure of 6.2 × 106 Pa. Data were generated using a bench scale continuous-flow reactor system to process feed water spiked with endotoxin standard (Escherichia coli O113:H10). Product water samples were collected and quantified by the Limulus amebocyte lysate assay. At 250°C, 5-log endotoxin inactivation was achieved in about 1 s of exposure, followed by a lower inactivation rate. This non-log-linear pattern is similar to reported trends in microbial survival curves. Predictions and parameters of several non-log-linear models are presented. In the fast-reaction zone (3- to 5-log reduction), the Arrhenius rate constant fits well at temperatures ranging from 120°C to 250°C on the basis of data from this work and the literature. Both biphasic and modified Weibull models are comparable to account for both the high and low rates of inactivation in terms of prediction accuracy and the number of parameters used. A unified representation of thermal resistance curves for a 3-log reduction and a 3 D value associated with endotoxin inactivation and microbial survival, respectively, is presented. PMID:21193667

Li, Lixiong; Wilbur, Chris L.; Mintz, Kathryn L.



Efficacy of the Combination of Tachyplesin III and Clarithromycin in Rat Models of Escherichia coli Sepsis?  

PubMed Central

We investigated the efficacy of tachyplesin III and clarithromycin in two experimental rat models of severe gram-negative bacterial infections. Adult male Wistar rats were given either (i) an intraperitoneal injection of 1 mg/kg Escherichia coli 0111:B4 lipopolysaccharide or (ii) 2 × 1010 CFU of E. coli ATCC 25922. For each model, the animals received isotonic sodium chloride solution, 1 mg/kg tachyplesin III, 50 mg/kg clarithromycin, or 1 mg/kg tachyplesin III combined with 50 mg/kg clarithromycin intraperitoneally. Lethality, bacterial growth in the blood and peritoneum, and the concentrations of endotoxin and tumor necrosis factor alpha (TNF-?) in plasma were evaluated. All the compounds reduced the lethality of the infections compared to that for the controls. Tachyplesin III exerted a strong antimicrobial activity and achieved a significant reduction of endotoxin and TNF-? concentrations in plasma compared to those of the control and clarithromycin-treated groups. Clarithromycin exhibited no antimicrobial activity but had a good impact on endotoxin and TNF-? plasma concentrations. A combination of tachyplesin III and clarithromycin resulted in significant reductions in bacterial counts and proved to be the most-effective treatment in reducing all variables measured. PMID:18779356

Cirioni, Oscar; Ghiselli, Roberto; Silvestri, Carmela; Kamysz, Wojciech; Orlando, Fiorenza; Riva, Alessandra; Kamysz, Elzbieta; Castelletti, Sefora; Rocchi, Marco; Saba, Vittorio; Scalise, Giorgio; Giacometti, Andrea



Stress-Derived Corticotropin Releasing Factor Breaches Epithelial Endotoxin Tolerance  

PubMed Central

Background and aims Loss of the endotoxin tolerance of intestinal epithelium contributes to a number of intestinal diseases. The etiology is not clear. Psychological stress is proposed to compromise the intestinal barrier function. The present study aims to elucidate the role of the stress-derived corticotropin releasing factor (CRF) in breaching the established intestinal epithelial endotoxin tolerance. Methods Epithelial cells of HT-29, T84 and MDCK were exposed to lipopolysaccharide to induce the endotoxin tolerance; the cells were then stimulated with CRF. The epithelial barrier function was determined using as indicators of the endotoxin tolerant status. A water-avoid stress mouse model was employed to test the role of CRF in breaching the established endotoxin tolerance in the intestine. Results The established endotoxin tolerance in the epithelial cell monolayers was broken down by a sequent exposure to CRF and LPS manifesting a marked drop of the transepithelial resistance (TER) and an increase in the permeability to a macromolecular tracer, horseradish peroxidase (HRP). The exposure to CRF also increased the expression of Cldn2 in the epithelial cells, which could be mimicked by over expression of TLR4 in epithelial cells. Over expression of Cldn2 resulted in low TER in epithelial monolayers and high permeability to HRP. After treating mice with the 10-day chronic stress, the intestinal epithelial barrier function was markedly compromised, which could be prevented by blocking either CRF, or TLR4, or Cldn2. Conclusions Psychological stress-derived CRF can breach the established endotoxin tolerance in the intestinal mucosa. PMID:23840363

Yu, Yong; Geng, Xiao-Rui; Yang, Gui; Liu, Zhi-Gang; Zheng, Peng-Yuan; Yang, Ping-Chang



Bench-to-bedside review: Endotoxin tolerance as a model of leukocyte reprogramming in sepsis  

PubMed Central

Endotoxin tolerance is defined as a reduced responsiveness to a lipopolysaccharide (LPS) challenge following a first encounter with endotoxin. Endotoxin tolerance protects against a lethal challenge of LPS and prevents infection and ischemia-reperfusion damage. Endotoxin tolerance is paralleled by a dramatic reduction of tumor necrosis factor (TNF) production and some other cytokines in response to LPS. Endotoxin tolerance involves the participation of macrophages and mediators, such as glucocorticoids, prostaglandins, IL-10, and transforming growth factor-?. Endotoxin tolerance is accompanied by the up-regulation of inhibitory molecules that down-regulate the Toll-like receptor (TLR)4-dependent signaling pathway. Cross-tolerance between LPS and other TLR specific ligands, as well as IL-1 and TNF, has been regularly reported. A similar loss of LPS reactivity has been repeatedly reported in circulating leukocytes of septic patients and in patients with non-infectious systemic inflammation response syndrome (SIRS). Studies on cellular signaling within leukocytes from septic and SIRS patients reveal numerous alterations reminiscent of those observed in endotoxin tolerant cells. However, altered responsiveness to LPS of leukocytes from sepsis and SIRS patients is not synonymous with a global down-regulation of cellular reactivity. The term 'cellular reprogramming', which has been proposed to qualify the process of endotoxin tolerance, defines well the immune status of circulating leukocytes in septic and SIRS patients. PMID:17044947

Cavaillon, Jean-Marc; Adib-Conquy, Minou



Puerarin ameliorates experimental alcoholic liver injury by inhibition of endotoxin gut leakage, Kupffer cell activation, and endotoxin receptors expression.  


Puerarin, an isoflavone component extracted from Kudzu (Pueraria lobata), has been demonstrated to alleviate alcohol-related disorders. Our study examined whether puerarin ameliorates chronic alcoholic liver injury through inhibition of endotoxin gut leakage, the subsequent Kupffer cell activation, and endotoxin receptors expression. Rats were provided with the Liber-DeCarli liquid diet for 8 weeks. Puerarin (90 mg/kg or 180 mg/kg daily) was orally administered from the beginning of the third week until the end of the experiment. Chronic alcohol intake caused increased serum alanine aminotransferase, aspartate aminotransferase, hepatic gamma-glutamyl transpeptidase, and triglyceride levels as well as fatty liver and neutrophil infiltration in hepatic lobules as determined by biochemical and histologic assays. A significant increase of liver tumor necrosis factor ? was detected by enzyme-linked immunosorbent assay. These pathologic effects correlated with increased endotoxin level in portal vein and upregulated protein expression of hepatic CD68, lipopolysaccharide-binding protein, CD14, Toll-like receptor 2, and Toll-like receptor 4. Meanwhile, the intestinal microvilli were observed to be sparse, shortened, and irregularity in distribution under the transmission electron microscope in conjunction with the downregulated intestinal zonula occludens-1 protein expression. These hepatic pathologic changes were significantly inhibited in puerarin-treated animals as were the endotoxin levels and hepatic CD68 and endotoxin receptors. Moreover, the pathologic changes in intestinal microvillus and the decreased intestinal zonula occludens-1 were also ameliorated with puerarin treatment. These results thus demonstrate that puerarin inhibition of endotoxin gut leakage, Kupffer cell activation, and endotoxin receptors expression is involved in the alleviation of chronic alcoholic liver injury in rats. PMID:23277536

Peng, Jing-Hua; Cui, Tuan; Huang, Fu; Chen, Liang; Zhao, Yu; Xu, Lin; Xu, Li-Li; Feng, Qin; Hu, Yi-Yang



Endotoxin and Cytokines Increase Hepatic Sphingolipid Biosynthesis and Produce Lipoproteins Enriched in Ceramides and Sphingomyelin  

Microsoft Academic Search

Alterations in triglyceride and cholesterol metabolism often accompany inflammatory diseases and infections. We studied the effects of endotoxin (lipopolysaccharide (LPS)) and cytokines on hepatic sphingolipid synthesis, activity of serine palmitoyltransferase (SPT), the first and rate-limiting enzyme in sphingolipid synthesis, and lipoprotein sphingolipid content in Syrian hamsters. Administration of LPS induced a 2-fold increase in hepatic SPT activity. The increase in

Riaz A. Memon; Walter M. Holleran; Arthur H. Moser; Taisuke Seki; Yoshikazu Uchida; John Fuller; Judy K. Shigenaga; Carl Grunfeld; Kenneth R. Feingold


Endotoxin-Induced Uveitis in the Rat Is Attenuated by Inhibition of Nitric Oxide Production  

Microsoft Academic Search

Purpose. These experiments were undertaken to assess the role of increased nitric oxide pro- duction in the pathogenesis of vascular dysfunction associated with endotoxin-induced uveitis. Methods. Lipopolysaccharides (LPS) (100 ng of Salmonella Minnesota) was injected into foot- pads of Lewis rats randomly assigned to an untreated group or to a group treated with subcuta- neous injections of aminoguanidine, a selective

Ronald G. Tilton; Kathy Chang; John A. Corbett; Thomas P. Misko; Mark G. Currie; Nalini S. Bora; Henry J. Kaplan; Joseph R. Williamson



Recognition of Gram-negative bacteria and endotoxin by the innate immune system  

Microsoft Academic Search

Until about 10 years ago the exact mechanisms controlling cellular responses to the endotoxin – or lipopolysaccharide (LPS) – of Gram-negative bacteria were unknown. Now a considerable body of evidence supports a model where LPS or LPS-containing particles (including intact bacteria) form complexes with a serum protein known as LPS-binding protein; the LPS in this complex is subsequently transferred to

Richard J Ulevitch; Peter S Tobias




EPA Science Inventory

Groups of male CBA/J mice were injected with Salmonella typhimurium lipopolysaccharide (LPS) and irradiated with 2450 MHz (CW) microwaves. High ambient temperature (37C) also potentiated the lethal effect of endotoxin. Microwave irradiation prior to LPS injection, however, did no...


Endotoxin and Cancer  

PubMed Central

Objective Exposure to endotoxin, a component of gram-negative bacterial cell walls, is widespread in many industrial settings and in the ambient environment. Heavy-exposure environments include livestock farms, cotton textile facilities, and saw mills. Concentrations are highly variable in non-occupational indoor and outdoor environments. Endotoxin is a potent inflammagen with recognized health effects, including fever, shaking chills, septic shock, toxic pneumonitis, and respiratory symptoms. Somewhat paradoxically, given the putative role of inflammation in carcinogenesis, various lines of evidence suggest that endotoxin may prevent cancer initiation or limit tumor growth. The hypothesis that components of bacteria may retard cancer progression dates back to William B. Coley’s therapeutic experiments (“bacterial vaccine”) in the 1890s. Data sources In this article, we review epidemiologic, clinical trial, and experimental studies pertinent to the hypothesis that endotoxin prevents cancer. Since the 1970s, epidemiologic studies of cotton textile and other endotoxin-exposed occupational groups have consistently demonstrated reduced lung cancer risks. Experimental animal toxicology research and some limited therapeutic trials in cancer patients offer additional support for an anticarcinogenic potential. The underlying biological mechanisms of anticarcinogenesis are not entirely understood but are thought to involve the recruitment and activation of immune cells and proinflammatory mediators (e.g., tumor necrosis factor ? and interleukin-1 and -6). Conclusions In view of the current state of knowledge, it would be premature to recommend endotoxin as a cancer-chemopreventive agent. Nonetheless, further epidemiologic and experimental investigations that can clarify further dose–effect and exposure–timing relations could have substantial public health and basic biomedical benefits. PMID:19750096

Lundin, Jessica I.; Checkoway, Harvey



Suppression of Murine Endotoxin Response by E5531, a Novel Synthetic Lipid A Antagonist  

PubMed Central

As a consequence of blood-borne bacterial sepsis, endotoxin or lipopolysaccharide (LPS) from the cell walls of gram-negative bacteria can trigger an acute inflammatory response, leading to a series of pathological events and often resulting in death. To block this inflammatory response to endotoxin, a novel lipid A analogue, E5531, was designed and synthesized as an LPS antagonist, and its biological properties were examined in vitro and in vivo. In murine peritoneal macrophages, E5531 inhibited the release of tumor necrosis factor alpha (TNF-?) by Escherichia coli LPS with a 50% inhibitory concentration (IC50) of 2.2 nM, while E5531 elicited no significant increases in TNF-? on its own. In support of a mechanism consistent with antagonism of binding to a cell surface receptor for LPS, E5531 inhibited equilibrium binding of radioiodinated LPS ([125I]2-(r-azidosalicylamido)-1, 3?-dithiopropionate-LPS) to mouse macrophages with an IC50 of 0.50 ?M. E5531 inhibited LPS-induced increases in TNF-? in vivo when it was coinjected with LPS into C57BL/6 mice primed with Mycobacterium bovis bacillus Calmette-Guérin (BCG). In this model, the efficacy of E5531 was inversely correlated to the LPS challenge dose, consistent with a competitive antagonist-like mechanism of action. Blockade of the inflammatory response by E5531 could further be demonstrated in other in vivo models: E5531 protected BCG-primed mice from LPS-induced lethality in a dose-dependent manner and suppressed LPS-induced hepatic injury in Propionibacterium acnes-primed or galactosamine-sensitized mice. These results argue that the novel synthetic lipid A analogue E5531 can antagonize the action of LPS in in vitro and suppress the pathological effects of LPS in vivo in mice. PMID:9797210

Kobayashi, Seiichi; Kawata, Tsutomu; Kimura, Akifumi; Miyamoto, Kaname; Katayama, Koichi; Yamatsu, Isao; Rossignol, Daniel P.; Christ, William J.; Kishi, Yoshito



Removal of endotoxin from water by microfiltration through a microporous polyethylene hollow-fiber membrane  

SciTech Connect

The microporous polyethylene hollow-fiber membrane has a unique microfibrile structure throughout its depth and has been found to possess the functions of filtration and adsorption of endotoxin in water. The membrane has a maximum pore diameter of approximately 0.04 micron, a diameter which is within the range of microfiltration. Approximately 10 and 20% of the endotoxin in tap water and subterranean water, respectively, was smaller than 0.025 micron. Endotoxin in these water sources was efficiently removed by the microporous polyethylene hollow-fiber membrane. Escherichia coli O113 culture broth contained 26.4% of endotoxin smaller than 0.025 micron which was also removed. Endotoxin was leaked into the filtrate only when endotoxin samples were successively passed through the membrane. These results indicate that endotoxin smaller than the pore size of the membrane was adsorbed and then leaked into the filtrate because of a reduction in binding sites. Dissociation of /sup 3/H-labeled endotoxin from the membrane was performed, resulting in the removal of endotoxin associated with the membrane by alcoholic alkali at 78% efficiency.

Sawada, Y.; Fujii, R.; Igami, I.; Kawai, A.; Kamiki, T.; Niwa, M.



Measurement of endotoxins in bioaerosols at workplace: a critical review of literature and a standardization issue.  


Endotoxins are lipopolysaccharides found in the outer membrane of most Gram-negative bacteria and cyanobacteria. Worker exposure to endotoxins has been shown in a number of work situations and is associated with both respiratory and systemic pathologies. The lack of an occupational exposure limit is mainly due to the absence of a standard protocol at the international level for sampling and analyzing airborne endotoxins. The bibliographic review in this article takes an exhaustive look at the current knowledge on measuring airborne endotoxins. It shows that, despite several reference documents at the international level, the methods used to measure endotoxin exposure differ considerably from one laboratory to another. Standardization is necessary to reduce interlaboratory variability and, ultimately, to improve the use of interstudy data. The bibliographic review presents the current status of standardization for airborne endotoxin measurement methods in the workplace and summarizes areas for further research. This article is both a reference document for all operators wishing to use such methods and a working document to build international consensus around the measurement of airborne endotoxins. PMID:23002277

Duquenne, Philippe; Marchand, Genevičve; Duchaine, Caroline



Endotoxin Structures in the Psychrophiles Psychromonas marina and Psychrobacter cryohalolentis Contain Distinctive Acyl Features  

PubMed Central

Lipid A is the essential component of endotoxin (Gram-negative lipopolysaccharide), a potent immunostimulatory compound. As the outer surface of the outer membrane, the details of lipid A structure are crucial not only to bacterial pathogenesis but also to membrane integrity. This work characterizes the structure of lipid A in two psychrophiles, Psychromonas marina and Psychrobacter cryohalolentis, and also two mesophiles to which they are related using MALDI-TOF MS and fatty acid methyl ester (FAME) GC-MS. P. marina lipid A is strikingly similar to that of Escherichia coli in organization and total acyl size, but incorporates an unusual doubly unsaturated tetradecadienoyl acyl residue. P. cryohalolentis also shows structural organization similar to a closely related mesophile, Acinetobacter baumannii, however it has generally shorter acyl constituents and shows many acyl variants differing by single methylene (-CH2-) units, a characteristic it shares with the one previously reported psychrotolerant lipid A structure. This work is the first detailed structural characterization of lipid A from an obligate psychrophile and the second from a psychrotolerant species. It reveals distinctive structural features of psychrophilic lipid A in comparison to that of related mesophiles which suggest constitutive adaptations to maintain outer membrane fluidity in cold environments. PMID:25010385

Sweet, Charles R.; Alpuche, Giancarlo M.; Landis, Corinne A.; Sandman, Benjamin C.




EPA Science Inventory

ABSTRACT The endotoxin component of organic dusts causes acute reversible airflow obstruction and airway inflammation. To test the hypothesis that endotoxin alone causes airway remodeling, we have compared the response of two inbred mouse strains to subchronic endotoxin ...


Response of Saccharomyces cerevisiae to the Stimulation of Lipopolysaccharide  

PubMed Central

Lipopolysaccharide, known as endotoxin, can stimulate potent host immune responses through the complex of Toll-like-receptor 4 and myeloid differentiation protein 2; but its influence on Saccharomyces cerevisiae, a model organism for studying eukaryotes, is not clear. In this study, we found that lipopolysaccharide-treated S. cerevisiae cells could be stained by methylene blue, but did not die. Transcriptional profiling of the lipopolysaccharide-treated S. cerevisiae cells showed that 5745 genes were modulated: 2491 genes up-regulated and 3254 genes down-regulated. Significantly regulated genes (460 up-regulated genes and 135 down-regulated genes) in lipopolysaccharide-treated S. cerevisiae cells were analyzed on Gene Ontology, and used to establish physical protein-protein interaction network and protein phosphorylation network. Based on these analyses, most of the regulated genes in lipopolysaccharide-treated S. cerevisiae cells were related to cell wall, membrane, peroxisome and mitochondrion. Further experiments demonstrated that lipopolysaccharide stimulation caused the exposure of phosphatidylserine and the increase of mitochondrial membrane potential in S. cerevisiae cells, but levels of intracellular reactive oxygen species and metacaspase activation were not increased. This study demonstrated that lipopolysaccharide stimulation causes significant changes in S. cerevisiae cells, and the results would contribute to understand the response of eukaryotic cells to lipopolysaccharide stimulation. PMID:25105496

Shen, Lulu; Li, Ye; Jiang, Linghuo; Wang, Xiaoyuan



Proteogenomics of selective susceptibility to endotoxin using circulating acute phase biomarkers and bioassay development in sheep: a review  

PubMed Central

Scientists have injected endotoxin into animals to investigate and understand various pathologies and novel therapies for several decades. Recent observations have shown that there is selective susceptibility to Escherichia coli lipopolysaccharide (LPS) endotoxin in sheep, despite having similar breed characteristics. The reason behind this difference is unknown, and has prompted studies aiming to explain the variation by proteogenomic characterisation of circulating acute phase biomarkers. It is hypothesised that genetic trait, biochemical, immunological and inflammation marker patterns contribute in defining and predicting mammalian response to LPS. This review discusses the effects of endotoxin and host responses, genetic basis of innate defences, activation of the acute phase response (APR) following experimental LPS challenge, and the current approaches employed in detecting novel biomarkers including acute phase proteins (APP) and micro-ribonucleic acids (miRNAs) in serum or plasma. miRNAs are novel targets for elucidating molecular mechanisms of disease because of their differential expression during pathological, and in healthy states. Changes in miRNA profiles during a disease challenge may be reflected in plasma. Studies show that gel-based two-dimensional electrophoresis (2-DE) coupled with either matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) or liquid chromatography–mass spectrometry (LC-MS/MS) are currently the most used methods for proteome characterisation. Further evidence suggests that proteomic investigations are preferentially shifting from 2-DE to non-gel based LC-MS/MS coupled with data extraction by sequential window acquisition of all theoretical fragment-ion spectra (SWATH) approaches that are able to identify a wider range of proteins. Enzyme-linked immunosorbent assay (ELISA), quantitative real-time polymerase chain reaction (qRT-PCR), and most recently proteomic methods have been used to quantify low abundance proteins such as cytokines. qRT-PCR and next generation sequencing (NGS) are used for the characterisation of miRNA. Proteogenomic approaches for detecting APP and novel miRNA profiling are essential in understanding the selective resistance to endotoxin in sheep. The results of these methods could help in understanding similar pathology in humans. It might also be helpful in the development of physiological and diagnostic screening assays for determining experimental inclusion and endpoints, and in clinical trials in future. PMID:24580811



Proteogenomics of selective susceptibility to endotoxin using circulating acute phase biomarkers and bioassay development in sheep: a review.  


Scientists have injected endotoxin into animals to investigate and understand various pathologies and novel therapies for several decades. Recent observations have shown that there is selective susceptibility to Escherichia coli lipopolysaccharide (LPS) endotoxin in sheep, despite having similar breed characteristics. The reason behind this difference is unknown, and has prompted studies aiming to explain the variation by proteogenomic characterisation of circulating acute phase biomarkers. It is hypothesised that genetic trait, biochemical, immunological and inflammation marker patterns contribute in defining and predicting mammalian response to LPS. This review discusses the effects of endotoxin and host responses, genetic basis of innate defences, activation of the acute phase response (APR) following experimental LPS challenge, and the current approaches employed in detecting novel biomarkers including acute phase proteins (APP) and micro-ribonucleic acids (miRNAs) in serum or plasma. miRNAs are novel targets for elucidating molecular mechanisms of disease because of their differential expression during pathological, and in healthy states. Changes in miRNA profiles during a disease challenge may be reflected in plasma. Studies show that gel-based two-dimensional electrophoresis (2-DE) coupled with either matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) or liquid chromatography-mass spectrometry (LC-MS/MS) are currently the most used methods for proteome characterisation. Further evidence suggests that proteomic investigations are preferentially shifting from 2-DE to non-gel based LC-MS/MS coupled with data extraction by sequential window acquisition of all theoretical fragment-ion spectra (SWATH) approaches that are able to identify a wider range of proteins. Enzyme-linked immunosorbent assay (ELISA), quantitative real-time polymerase chain reaction (qRT-PCR), and most recently proteomic methods have been used to quantify low abundance proteins such as cytokines. qRT-PCR and next generation sequencing (NGS) are used for the characterisation of miRNA. Proteogenomic approaches for detecting APP and novel miRNA profiling are essential in understanding the selective resistance to endotoxin in sheep. The results of these methods could help in understanding similar pathology in humans. It might also be helpful in the development of physiological and diagnostic screening assays for determining experimental inclusion and endpoints, and in clinical trials in future. PMID:24580811

Chemonges, Saul; Tung, John-Paul; Fraser, John F



Endotoxin removal from protein solutions.  


Endotoxins liberated by gram-negative bacteria are frequent contaminations of protein solutions derived from bioprocesses. Because of their high toxicity in vivo and in vitro, their removal is essential for a safe parenteral administration. A general method for the removal of endotoxins from protein solutions is not available. Methods used for decontamination of water, such as ultrafiltration, have little effect on endotoxin levels in protein solutions. Various techniques described in the patent literature are not broadly applicable, as they are tailored to meet specific product requirements. Besides ion-exchangers and two-phase extraction, affinity techniques are applied with varying success. Also, taylor-made endotoxin-selective adsorber matrices for the prevention of endotoxin contamination and endotoxin removal are discussed for this purpose. After giving an overview of the properties of endotoxins and the significance of endotoxin contamination, this review intends to provide an overall picture of the various methods employed for their removal. Avenues are pointed out how to optimise a method with regard to the specific properties of endotoxins in aqueous solution. PMID:10656326

Petsch, D; Anspach, F B



N-Acetylcysteine ameliorates lipopolysaccharide-induced organ damage in conscious rats  

Microsoft Academic Search

Lipopolysaccharide is strongly associated with septic shock, leading to multiple organ failure. It can activate monocytes and macrophages to release proinflammatory mediators such as tumor necrosis factor-? (TNF-?), interleukin-1? (IL-1?), and nitric oxide (NO). The present experiments were designed to induce endotoxin shock by an intravenous injection ofKlebsiella pneumoniae lipopolysaccharide (LPS, 10 mg\\/kg) in conscious rats. Arterial pressure and heart

Bang Gee Hsu; Fwu Lin Yang; Ru Ping Lee; Tai Chu Peng; Horng Jyh Harn; Hsing I. Chen



Central and peripheral adrenergic mechanisms in endotoxin fever and newborn guinea pigs.  


In 0--3 day-old guinea pigs cerebroventricular pretreatment with alpha-methyl-p-tyrosine failed to modify the course of fever induced by E. coli endotoxin administration into the cerebral ventricles. Central or intraperitoneal administration of phentolamine or central administration of propranolol were also ineffective. Intraperitoneal propranolol, however, prevented both the first and the second temperature rise after endotoxin, while the transient fall in temperature that usually occurs between them still ensued. Central noradrenergic mechanisms seem to play, at most, a minor role in the mediation of endotoxin fever, while the integrity of peripheral beta adrenergic receptors is indispensable for the febrile response to occur. PMID:233404

Székely, M



Airborne Endotoxin Associated with Industrial-Scale Production of Protein Products in Gram-Negative Bacteria  

Microsoft Academic Search

Human and animal proteins of therapeutic value can be produced in E. coli, a gram-negative bacteria. Endotoxin, a cellular component, is reported to have clinically significant health effects. Operations—including culturing the microbe, separating solids by centrifugation, and mixing\\/homogenizing—had associated endotoxin levels ranging from 0.07?ng\\/m to 12.8?ng\\/m. Utilizing a 10-fold safety factor under the threshold where clinically significant changes can be




Effect of heat-killed Escherichia coli, lipopolysaccharide, and muramyl dipeptide treatments on the immune response phenotype and allergy in neonatal pigs sensitized to the egg white protein ovomucoid.  


Predisposition to food allergies may reflect a type 2 immune response (IR) bias in neonates due to the intrauterine environment required to maintain pregnancy. The hygiene hypothesis states that lack of early environmental stimulus leading to inappropriate development and bias in IR may also contribute. Here, the ability of heat-killed Escherichia coli, lipopolysaccharide (LPS), or muramyl dipeptide (MDP) to alter IR bias and subsequent allergic response in neonatal pigs was investigated. Three groups of three litters of pigs (12 pigs/litter) were given intramuscular injections of E. coli, LPS, MDP, or phosphate-buffered saline (PBS) (control) and subsequently sensitized to the egg white allergen ovomucoid using an established protocol. To evaluate change in IR bias, immunoglobulin isotype-associated antibody activity (AbA), concentrations of type 1 and 2 and proinflammatory cytokines released from mitogen-stimulated blood mononuclear cells, and the percentage of T-regulatory cells (T-regs) in blood were measured. Clinical signs of allergy were assessed after oral challenge with egg white. The greatest effect on IR bias was observed in MDP-treated pigs, which had a type 2-biased phenotype by isotype-specific AbA, cytokine production, and a low proportion of T-regs. LPS-treated pigs had decreased type 1- and type 2-associated AbA. E. coli-treated pigs displayed increased response to Ovm as AbA and had more balanced cytokine profiles, as well as the highest proportion of T-regs. Accordingly, pigs treated with MDP were more susceptible to allergy than PBS controls, while pigs treated with LPS were less susceptible. Treatment with E. coli did not significantly alter the frequency of clinical signs. PMID:23081818

Schmied, Julie; Rupa, Prithy; Garvie, Sarah; Wilkie, Bruce



Effect of Heat-Killed Escherichia coli, Lipopolysaccharide, and Muramyl Dipeptide Treatments on the Immune Response Phenotype and Allergy in Neonatal Pigs Sensitized to the Egg White Protein Ovomucoid  

PubMed Central

Predisposition to food allergies may reflect a type 2 immune response (IR) bias in neonates due to the intrauterine environment required to maintain pregnancy. The hygiene hypothesis states that lack of early environmental stimulus leading to inappropriate development and bias in IR may also contribute. Here, the ability of heat-killed Escherichia coli, lipopolysaccharide (LPS), or muramyl dipeptide (MDP) to alter IR bias and subsequent allergic response in neonatal pigs was investigated. Three groups of three litters of pigs (12 pigs/litter) were given intramuscular injections of E. coli, LPS, MDP, or phosphate-buffered saline (PBS) (control) and subsequently sensitized to the egg white allergen ovomucoid using an established protocol. To evaluate change in IR bias, immunoglobulin isotype-associated antibody activity (AbA), concentrations of type 1 and 2 and proinflammatory cytokines released from mitogen-stimulated blood mononuclear cells, and the percentage of T-regulatory cells (T-regs) in blood were measured. Clinical signs of allergy were assessed after oral challenge with egg white. The greatest effect on IR bias was observed in MDP-treated pigs, which had a type 2-biased phenotype by isotype-specific AbA, cytokine production, and a low proportion of T-regs. LPS-treated pigs had decreased type 1- and type 2-associated AbA. E. coli-treated pigs displayed increased response to Ovm as AbA and had more balanced cytokine profiles, as well as the highest proportion of T-regs. Accordingly, pigs treated with MDP were more susceptible to allergy than PBS controls, while pigs treated with LPS were less susceptible. Treatment with E. coli did not significantly alter the frequency of clinical signs. PMID:23081818

Schmied, Julie; Rupa, Prithy; Garvie, Sarah



Single session of Nd:YAG laser intracanal irradiation neutralizes endotoxin in dental root dentin  

NASA Astrophysics Data System (ADS)

Endotoxins released in the dental root by Gram-negative microorganisms can be neutralized by calcium hydroxide, when this medication is applied inside the root canal for at least seven days. However, several clinical situations demand faster root canal decontamination. Thus, for faster endotoxin neutralization, endodontists are seeking additional treatments. The in vitro study tested whether or not intracanal Nd:YAG laser irradiation would be able to neutralize endotoxin within the human dental root canal in a single session. Twenty-four human teeth with one root were mounted between two chambers. After conventional endodontic treatment, root canals were contaminated with Escherichia coli endotoxin. Then they were irradiated or not (controls) in contact mode with an Nd:YAG laser (1.5 W, 15 Hz, 100 mJ and pulse fluency of 124 J/cm2). The endotoxin activity was measured using the limulus lysate technique and data were statistically compared (p?0.05). The concentration of active endotoxin measured in the negative control group was significantly lower than that of the positive control group (p=0.04). The concentrations of endotoxin in both irradiated groups were significantly lower than that of the positive control group (p=0.027) and similar to that of negative control group (p=0.20). A single session of intracanal Nd:YAG laser irradiation is able to neutralize endotoxin in the dental root tissues.

Archilla, José R. F.; Moreira, Maria S. N. A.; Miyagi, Sueli P. H.; Bombana, Antônio C.; Gutknecht, Norbert; Marques, Márcia M.



Endotoxin elimination in sepsis: physiology and therapeutic application  

Microsoft Academic Search

Purpose  The present review summarizes key papers on the elimination of endotoxin in human.\\u000a \\u000a \\u000a \\u000a Results  Lipopolysaccharides (LPS) are extremely strong stimulators of inflammatory reactions, act at very low concentrations, and\\u000a are involved in the pathogenesis of sepsis and septic shock. Elimination of LPS is vital; therefore, therapeutic detoxification\\u000a of LPS may offer new perspectives. Multiple mechanisms eliminate LPS in human comprising molecules

Klaus Buttenschoen; Peter Radermacher; Hendrik Bracht



Temperament influences endotoxin-induced changes in rectal temperature, sickness behavior, and plasma epinephrine concentrations in bulls  

Technology Transfer Automated Retrieval System (TEKTRAN)

This study was designed to determine the influence of temperament on endotoxin (lipopolysaccharide; LPS) induced changes in body temperature and the secretion of cortisol and epinephrine. Purebred Brahman bulls were selected based on temperament score (average of exit velocity, EV, and pen score, PS...


OmniGen-AF supplementation modulated the physiological and acute phase responses of Brahman heifers to an endotoxin challenge  

Technology Transfer Automated Retrieval System (TEKTRAN)

This study examined the effect of feeding OmniGen-AF (OG; Prince Agri Products) on the physiological and acute phase responses (APR) of newly-weaned heifers to an endotoxin (lipopolysaccharide; LPS) challenge. Brahman heifers (n=24; 183±5 kilograms) from the Texas AgriLife Research Center in Overton...


The effect of yeast cell wall supplementation on the metabolic responses of crossbred heifers to endotoxin challenge  

Technology Transfer Automated Retrieval System (TEKTRAN)

This study examined the effect of feeding yeast cell wall (YCW) products on the metabolic responses of newly-received heifers to endotoxin (lipopolysaccharide; LPS) challenge. Heifers (n=24; 218.9±2.4 kg) were obtained from commercial sale barns and transported to the Texas Tech University Beef Cent...


Low Levels of Endotoxin Enhance Allergen-Stimulated Proliferation and Reduce the Threshold for Activation in Human Peripheral Blood Cells  

Microsoft Academic Search

Background: Endotoxins, comprised of bacterial cell wall lipopolysaccharides (LPS), have been reported to have both protective and exacerbating effects on the development and maintenance of allergic disease in humans and on markers of allergic inflammation in animal models of allergy. In this study, we investigated the effect of low concentrations of LPS on human peripheral blood mononuclear cells (PBMC) stimulated

Tanja Cirkovic Velickovic; Sarah Thunberg; Natalija Polovic; Theresa Neimert-Andersson; Hans Grönlund; Marianne van Hage; Guro Gafvelin



Human endotoxin tolerance is associated with enrichment of the CD14+ CD16+ monocyte subset.  


Prior exposure to lipopolysaccharides (LPS) induces a state of cell resistance to subsequent LPS restimulation, known as endotoxin tolerance, mainly by repressing the expression of pro-inflammatory cytokines. We established an endotoxin tolerance model in human monocytes Endotoxin-tolerant cells showed a decrease in I?B? degradation and diminished expression of Tumor necrosis factor (TNF) (both messenger RNA [mRNA] and protein content). The myeloid differentiation factor 88 (MyD88)/MyD88 splice variant (MyD88s) ratio, an indirect way to test the Toll-like receptor 4 (TLR4) MyD88-dependent signaling cascade, did not change in endotoxin-tolerant cells when compared to LPS-stimulated or -unstimulated ones. Remarkably, cell population analysis indicated a significant increase of the CD14+ CD16+ subset only under the endotoxin-tolerant condition. Furthermore, endotoxin-tolerant cells produced higher amounts of C-X-C motif chemokine 10 (CXCL10), a typical MyD88-independent cytokine. PMID:25172544

Domínguez-Nieto, Aimée; Zentella, Alejandro; Moreno, José; Ventura, José L; Pedraza, Sigifredo; Velázquez, Juan R



Removal of endotoxin from deionized water using micromachined silicon nanopore membranes  

NASA Astrophysics Data System (ADS)

Endotoxins are lipopolysaccharide components of the cell membrane of Gram-negative bacteria that trigger the body's innate immune system and can cause shock and death. Water for medical therapy, including parenteral and dialysate solutions, must be free of endotoxin. This purity is challenging to achieve as many Gram-negative bacteria are endemic in the environment, and can thrive in harsh, nutrient-poor conditions. Current methods for removing endotoxin include distillation and reverse osmosis, both of which are resource intensive processes. Membranes that present an absolute barrier to macromolecular passage may be capable of delivering pure water for biomedical applications. In this work, endotoxin has been filtered from aqueous solutions using silicon nanopore membranes (SNMs) with monodisperse pore size distributions. SNMs with critical pore sizes between 26 and 49 nm were challenged with solutions of deionized water spiked with endotoxin and with Pseudomonas cepacia. The filtrate produced by the SNM from Pseudomonas-contaminated water had <1.0 endotoxin unit (EU) ml-1, which meets standards for dialysate purity. This approach suggests a technique for single-step cleanup of heavily contaminated water that may be suitable for field or clinical use.

Smith, Ross A.; Goldman, Ken; Fissell, William H.; Fleischman, Aaron J.; Zorman, Christian A.; Roy, Shuvo



Lipopolysaccharide preconditioning and cross-tolerance: The induction of protective mechanisms for rat intestinal ileus  

Microsoft Academic Search

Background & Aims: Endotoxin elicits an inflammatory response within the intestinal muscularis and causes intestinal muscle dysfunction. Our aims were to investigate intestinal muscle recovery after a single or repeated lipopolysaccharide (LPS) injections. We also investigated the ability of LPS to induce cross-tolerance to postoperative ileus. Methods: Motility was measured in vivo and in vitro by transit and organ-bath techniques.

Nicolas T. Schwarz; Britta Engel; Mark K. Eskandari; Jörg C. Kalff; Jennifer R. Grandis; Anthony J. Bauer



Lipopolysaccharide affinity for titanium implant biomaterials  

Microsoft Academic Search

Statement of problem. Lipopolysaccharide (LPS) affinity for titanium implant biomaterials could affect crevicular LPS concentrations and thereby influence periimplant inflammation.Purpose of study. The purpose of this study was to evaluate Porphyromonas gingivalis and Escherichia coli LPS affinity for titanium biomaterials groups that differed in surface oxide composition and surface roughness.Material and method. Polished and abraded grade 1 commercially pure titanium

Steven K. Nelson; Kent L. Knoernschild; Fonda G. Robinson; George S. Schuster



The Limulus Amebocyte Lysate assay may be unsuitable for detecting endotoxin in blood of healthy female subjects.  


We examined the factors that may influence the outcome of the Limulus Amebocyte Lysate (LAL) assay, when it is used for quantifying Gram-negative bacterial endotoxin, also referred to as lipopolysaccharide (LPS), in samples of human blood. We found that the method recommended by the manufacturers, based on the reaction time, was inaccurate with any type of serum samples due to the slowing of the initial phase of reaction, likely by serum proteins. We describe an alternative method that is more accurate for use with heated serum samples. Further, we found that components of fresh serum irreversibly sequester endotoxin but that this action may be largely prevented by dilution and heating, but only if this occurs prior to the addition of endotoxin. The tests also indicated that a number of types of proprietary plastic vacutainers appeared to contain significant amounts of endotoxin. However, even when appropriate blood collection containers and calculation methods were used, the levels of endotoxin in serum samples detected by LAL assay were unlikely to reflect the total quantities of endotoxin in that sample and more likely to reflect the capacity of a given serum sample to sequester endotoxin. PMID:25433222

Gnauck, Anne; Lentle, Roger G; Kruger, Marlena C



The Role of Cyclooxygenases in Endotoxin and Interleukin1Induced Hypophagia  

Microsoft Academic Search

Endotoxin (lipopolysaccharide, LPS) and interleukin-1 (IL-1) reduce food intake in rodents. Cyclooxygenase (COX) inhibitors have long been known to attenuate these responses, but recent work has revealed the existence of two distinct isoforms of the enzyme, COX1 and COX2, with different characteristics and functions. Therefore, we reassessed the COX involvement using inhibitors with different selectivities for COX1 and COX2. Feeding

Adrian J. Dunn; Artur H. Swiergiel



Pirfenidone prevents endotoxin-induced liver injury after partial hepatectomy in rats  

Microsoft Academic Search

Background\\/Aims: Massive liver resection causes a variety of complications including endotoxemia. Pirfenidone (PFD) is a new experimental drug used as antifibrotic agent. Studies were performed to investigate whether PFD influences the survival rate of animals with endotoxin-induced liver injury after partial hepatectomy, and the mechanisms involved.Methods: Rats were treated with lipopolysaccharide (LPS) 48 h after 70% hepatectomy. PFD was administered

Hideto Tsuchiya; Masaki Kaibori; Hidesuke Yanagida; Norio Yokoigawa; A-Hon Kwon; Tadayoshi Okumura; Yasuo Kamiyama



In silico designed nanoMIP based optical sensor for endotoxins monitoring.  


Molecular modelling was used to select specific monomers suitable for the design of molecularly imprinted polymers (MIPs) with high affinity towards endotoxins. MIPs were synthesised using solid-phase photopolymerisation with endotoxins from Escherichia coli 0111:B4 as the template. This technique also allowed the endotoxin template to be reused successfully. Particle size of ~190-220nm was achieved with low polydispersity index, which confirms the quality of the produced MIPs. For the development of the optical sensor, SPR-2 biosensor system was used by functionalising the gold sensor chip with the MIP nanoparticles using EDC/NHS coupling procedure. The affinity based-endotoxin assay can detect endotoxins in the concentration range of 15.6-500ngmL(-1). MIP surfaces were regenerated showing stability of the method for subsequent analysis and dissociation constants were calculated as 3.24-5.24×10(-8)M. The developed SPR sensor with the novel endotoxins nanoMIP showed the potential of the technology for endotoxins capture, detection and risk management and also the importance of computational modelling to design the artificial affinity ligands. PMID:25155060

Abdin, M J; Altintas, Z; Tothill, I E



Escherichia coli-Induced Activation of Neutrophil NADPH-Oxidase: Lipopolysaccharide and Formylated Peptides Act Synergistically To Induce Release of Reactive Oxygen Metabolites  

Microsoft Academic Search

The prevailing view of neutrophil NADPH-oxidase activation during interaction with bacteria is that the production of toxic oxygen metabolites should be directed into the phagosome containing the engulfed prey. However, in this report we show that a common Escherichia coli strain, HB101, may induce a release of neutrophil oxygen metabolites to the extracellular milieu. This phenomenon is dependent on three



Chlamydial hemagglutinin identified as lipopolysaccharide.  


Chlamydial lipopolysaccharide (LPS) agglutinated mouse and rabbit erythrocytes but not human, guinea pig, or pronghorn antelope erythrocytes. Hemagglutination was not specific for Chlamydia spp., as rough LPSs from Coxiella burnetii and Escherichia coli also agglutinated erythrocytes from the same animal species. Nonagglutinated and agglutinated erythrocytes bound equivalent amounts of LPS, indicating that hemagglutination was not due to a specific interaction of chlamydial LPS with erythrocytes. Thus, hemagglutination by chlamydial LPS is not mediated by specific receptor-ligand interactions but is a property of the altered surface of the LPS-coated erythrocytes. PMID:3301820

Watkins, N G; Caldwell, H D; Hackstadt, T



Effects of endotoxin induced lung injury and exercise in goats/sheep. Final report, 1 February 1992-2 June 1993  

SciTech Connect

This study was designed the effects of exercise performed on animals already injured with E. coli endotoxin. This would tell us whether exercise makes the lung injury worse. It would also tell us how much exercise performance is impaired. These studies were designed to give further insights into the underlying causes of acute lung injury. Premature termination of the study prevented completion of the research project. It appeared from the limited experimentation conducted that maximal exercise was impaired by endotoxin-induced lung injury. Conclusions regarding exacerbation of endotoxin-induced lung injury cannot be made.... Acute lung injury, Maximal exercise, Endotoxin.

Mundie, T.G.



Yohimbine ameliorates the effects of endotoxin on gastric emptying of the liquid marker acetaminophen in horses.  

PubMed Central

The effect of yohimbine pretreatment on gastric emptying of a liquid marker in horses was evaluated by measuring serum concentrations of acetaminophen. Gastric emptying was determined in normal, fasted horses, in horses given endotoxin (E. coli 055 B5; 0.2 microg/kg) intravenously, and in horses given yohimbine (0.25 mg/kg, IV, over 30 minutes) plus endotoxin. Acetaminophen (20 mg/kg) was given by stomach tube 15 minutes after the endotoxin infusion. Blood samples for acetaminophen analysis were collected, and time to reach the peak serum concentration (Tmax), the maximum serum concentration (Cmax) and the area under the acetaminophen serum concentration versus time curve (AUC) were determined for each treatment group. Endotoxin significantly increased Tmax, indicating a profound delay in gastric emptying and yohimbine pretreatment significantly (P < or = 0.05) prevented this effect. PMID:11041497

Meisler, S D; Doherty, T J; Andrews, F M; Osborne, D; Frazier, D L



Endotoxin-induced enteric hypomotility in jaundiced loops in vitro.  


Biliary obstruction may be accompanied by systemic endotoxemia due to increased growth of enteric microbiota and failure of hepatic clearance mechanisms. This endotoxemia is related to increased postoperative morbidity and mortality. An increased growth of the aerobic flora has been demonstrated experimentally in the presence of biliary obstruction, and in previous studies we observed intestinal hypomotility of jaundiced loops in vitro. To determine the ileal motor response in the presence of jaundice caused by biliary obstruction and in the presence of endotoxemia, an in vitro study was carried out on ileal segments from 10 female Holtzman rats, 2-3 months old, weighing 200 to 300 g, divided into two groups (N = 5); A, washed loops of jaundiced rats, and B, washed loops of jaundiced rats to which endotoxin was added. On the seventh postoperative day, we evaluated the effect of exogenous endotoxin (E. coli 0111:B4, Sigma) on the motor response to acetylcholine of distal ileal segments isolated from both animal groups. A 4-cm ileal segment, located 10 cm from the ileal papilla, was removed and studied in an organ chamber in order to assess dose-response curves to acetylcholine. There was an increase in threshold dose in jaundiced loops with intraluminally injected endotoxin when compared with the loops without intraluminal endotoxin (291 +/- 188 vs 8.5 +/- 6.7 microM, P < 0.05). The maximum contraction was reduced in jaundiced loops with intraluminal endotoxin in relation to control loops (5.3 +/- 1.7 vs 18.7 +/- 4.8 mm, P < 0.05), and pD2 was also reduced in jaundiced loops with intraluminal endotoxin in relation to control loops (2.4 +/- 0.6 vs 3.7 +/- 0.5, P < 0.05). There was no statistical difference between jaundiced loops with and without intraluminal endotoxin when the maximal contraction doses were compared (86 +/- 66 vs 48 +/- 22 mM, P > 0.05). These results demonstrate that intraluminal endotoxin depressed enteric motility in jaundiced rats. PMID:9181080

Duval-Araujo, I; Petroianu, A; Oliveira-Neto, J E; Sabino, L O



Hyperphagocytosis and the effect of lipopolysaccharide injection in tumour-bearing mice.  

PubMed Central

(AxT6)F1 hybrid mice received s.c. transplants from (AxT6)F1 mammary carcinomas. At 1, 2 or 4 weeks after tumour transplantation, the mice were bled to obtain plasma and then challenged with 25 micron E. coli lipopolysaccharide (LPS) endotoxin i.v. The mice were killed 24 hr later, further plasma was obtained and their liver ratios and spleen ratios were determined. A similar procedure was carried out on non-tumour-bearing mice. Progressive tumour growth was associated with an increase in the liver ratio. In parallel, mice with 4-week tumour transplant showed increased uptake of colloidal carbon particles and 51Cr-labelled sheep red blood cells in the liver. The plasma amino aspartate transaminase (AST) and the ornithine carbamoyl transferase (OCT) showed a constant rise in all groups of mice after LPS injection. However, at 24 hr after LPS injection, the AST level showed the greatest rise in mice with 4-week tumour transplants. By contrast, OCT, which is liberated only from hepatocytes, showed the greatest rise in non-tumour-bearing mice. Images Fig. 2 Fig. 3 PMID:7459224

Bradfield, J. W.; Whitmarsh-Everiss, T.; Palmer, D. B.; Payne, R.; Symes, M. O.



Effect of the lipopolysaccharide antagonist Planktothrix sp. FP1 cyanobacterial extract on human polymorphonuclear leukocytes.  


CyP is a lipopolysaccharide (LPS)-like molecule extracted from the freshwater cyanobacterium Oscillatoria planktothrix FP1, which has been reported to be a potent competitive inhibitor of bacterial LPS. In the present study the ability of CyP to affect human polymorphonuclear leukocyte (PMN) function was investigated. PMNs were isolated from venous blood by standard density-gradient centrifugation. Cell migration was measured by use of the Boyden chamber assay. Interleukin (IL)-8 and tumor necrosis factor (TNF)-? production was measured using a sandwich-type enzyme-linked immunosorbent assay. PMN intracellular reactive oxygen species (ROS) levels were assessed by the use of a fluorescent probe coupled to spectrophotometry. CyP 10-100 ?g/ml was chemotactic for PMNs without affecting the chemotactic response to either E. coli LPS or N-formyl-Met-Leu-Phe (fMLP). CyP per se did not affect PMN production of either IL-8 or TNF-?, but concentration-dependently reduced LPS-induced production of both cytokines. On the contrary, CyP had no effect either on fMLP-induced production of IL-8 or on PMN oxidative burst (at rest and after stimulation with fMLP), a response which is known to be independent from LPS-operated pathways. In human PMNs CyP behaves as a selective and effective LPS antagonist. These findings support the therapeutic potential of CyP in endotoxin-dependent disease. PMID:21115122

Maio, Ramňna Consučlo; Cosentino, Marco; Rossetti, Carlo; Molteni, Monica; Lecchini, Sergio; Marino, Franca



Bupleurum Polysaccharides Attenuates Lipopolysaccharide-Induced Inflammation via Modulating Toll-Like Receptor 4 Signaling  

PubMed Central

Background Bupleurum polysaccharides (BPs), isolated from Bupleurum smithii var. parvifolium, possesses immunomodulatory activity, particularly on inflammation. Bacterial endotoxin lipopolysaccharide (LPS) triggers innate immune responses through Toll-like receptor 4 (TLR4) on host cell membrane. The present study was performed to evaluate whether the therapeutic efficacy of BPs on suppression of LPS’s pathogenecity could be associated with the modulating of TLR4 signaling pathway. Methodology/Principal Findings LPS stimulated expression and activation of factors in the TLR4 signaling system, including TLR4, CD14, IRAK4, TRAF6, NF-?B, and JNK, determined using immunocytochemical and/or Western blot assays. BPs significantly inhibited these effects of LPS. LPS increased pro-inflammatory cytokines (TNF-?, IL-6, IL-1?, IL-12p40, and IFN-?) and NO production, evaluated using ELISA and Griess reaction assays, respectively. BPs antagonized these effects of LPS. Interestingly, BPs alone augmented secretion of some pro-inflammatory cytokines of non-LPS stimulated macrophages and enhanced phagocytic activity towards fluorescent E.coli bioparticles. In a rat model of acute lung injury (ALI) with pulmonary hemorrhage and inflammation, BPs ameliorated lung injuries and suppressed TLR4 expression. Significance The therapeutic properties of BPs in alleviating inflammatory diseases could be attributed to its inhibitory effect on LPS-mediated TLR4 signaling. PMID:24167596

Wu, Jian; Zhang, Yun-Yi; Guo, Li; Li, Hong; Chen, Dao-Feng



Functional Characterization and Membrane Topology of Escherichia coli WecA, a Sugar-Phosphate Transferase Initiating the Biosynthesis of Enterobacterial Common Antigen and O-Antigen Lipopolysaccharide?  

PubMed Central

WecA is an integral membrane protein that initiates the biosynthesis of enterobacterial common antigen and O-antigen lipopolysaccharide (LPS) by catalyzing the transfer of N-acetylglucosamine (GlcNAc)-1-phosphate onto undecaprenyl phosphate (Und-P) to form Und-P-P-GlcNAc. WecA belongs to a large family of eukaryotic and prokaryotic prenyl sugar transferases. Conserved aspartic acids in putative cytoplasmic loops 2 (Asp90 and Asp91) and 3 (Asp156 and Asp159) were targeted for replacement mutagenesis with either glutamic acid or asparagine. We examined the ability of each mutant protein to complement O-antigen LPS synthesis in a wecA-deficient strain and also determined the steady-state kinetic parameters of the mutant proteins in an in vitro transfer assay. Apparent Km and Vmax values for UDP-GlcNAc, Mg2+, and Mn2+ suggest that Asp156 is required for catalysis, while Asp91 appears to interact preferentially with Mg2+, possibly playing a role in orienting the substrates. Topological analysis using the substituted cysteine accessibility method demonstrated the cytosolic location of Asp90, Asp91, and Asp156 and provided a more refined overall topological map of WecA. Also, we show that cells expressing a WecA derivative C terminally fused with the green fluorescent protein exhibited a punctate distribution of fluorescence on the bacterial surface, suggesting that WecA localizes to discrete regions in the bacterial plasma membrane. PMID:17237164

Lehrer, Jason; Vigeant, Karen A.; Tatar, Laura D.; Valvano, Miguel A.



Obesity Increases Sensitivity to Endotoxin Liver Injury: Implications for the Pathogenesis of Steatohepatitis  

NASA Astrophysics Data System (ADS)

Genetically obese fatty/fatty rats and obese/obese mice exhibit increased sensitivity to endotoxin hepatotoxicity, quickly developing steatohepatitis after exposure to low doses of lipopolysaccharide (LPS). Among obese animals, females are more sensitive to endotoxin liver injury than males. LPS induction of tumor necrosis factor ? (TNF? ), the proven affecter of endotoxin liver injury, is no greater in the livers, white adipose tissues, or sera of obese animals than in those of lean controls. Indeed, the lowest serum concentrations of TNF occur in female obese rodents, which exhibit the most endotoxin-induced liver injury. Several cytokines that modulate the biological activity of TNF are regulated abnormally in the livers of obese animals. After exposure to LPS, mRNA of interferon ? , which sensitizes hepatocytes to TNF toxicity, is overexpressed, and mRNA levels of interleukin 10, a TNF inhibitor, are decreased. The phagocytic activity of liver macrophages and the hepatic expression of a gene encoding a macrophage-specific receptor are also decreased in obesity. This new animal model of obesity-associated liver disease demonstrates that hepatic macrophage dysfunction occurs in obesity and suggests that this might promote steatohepatitis by sensitizing hepatocytes to endotoxin.

Yang, Shi Qi; Zhi Lin, Hui; Lane, M. Daniel; Clemens, Mark; Diehl, Anna Mae



Endotoxin induces fibrosis in vascular endothelial cells through a mechanism dependent on transient receptor protein melastatin 7 activity.  


The pathogenesis of systemic inflammatory diseases, including endotoxemia-derived sepsis syndrome, is characterized by endothelial dysfunction. It has been demonstrated that the endotoxin lipopolysaccharide (LPS) induces the conversion of endothelial cells (ECs) into activated fibroblasts through endothelial-to-mesenchymal transition mechanism. Fibrogenesis is highly dependent on intracellular Ca2+ concentration increases through the participation of calcium channels. However, the specific molecular identity of the calcium channel that mediates the Ca2+ influx during endotoxin-induced endothelial fibrosis is still unknown. Transient receptor potential melastatin 7 (TRPM7) is a calcium channel that is expressed in many cell types, including ECs. TRPM7 is involved in a number of crucial processes such as the conversion of fibroblasts into activated fibroblasts, or myofibroblasts, being responsible for the development of several characteristics of them. However, the role of the TRPM7 ion channel in endotoxin-induced endothelial fibrosis is unknown. Thus, our aim was to study whether the TRPM7 calcium channel participates in endotoxin-induced endothelial fibrosis. Using primary cultures of ECs, we demonstrated that TRPM7 is a crucial protein involved in endotoxin-induced endothelial fibrosis. Suppression of TRPM7 expression protected ECs from the fibrogenic process stimulated by endotoxin. Downregulation of TRPM7 prevented the endotoxin-induced endothelial markers decrease and fibrotic genes increase in ECs. In addition, TRPM7 downregulation abolished the endotoxin-induced increase in ECM proteins in ECs. Furthermore, we showed that intracellular Ca2+ levels were greatly increased upon LPS challenge in a mechanism dependent on TRPM7 expression. These results demonstrate that TRPM7 is a key protein involved in the mechanism underlying endotoxin-induced endothelial fibrosis. PMID:24710004

Echeverría, Cesar; Montorfano, Ignacio; Hermosilla, Tamara; Armisén, Ricardo; Velásquez, Luis A; Cabello-Verrugio, Claudio; Varela, Diego; Simon, Felipe



Endotoxin Induces Fibrosis in Vascular Endothelial Cells through a Mechanism Dependent on Transient Receptor Protein Melastatin 7 Activity  

PubMed Central

The pathogenesis of systemic inflammatory diseases, including endotoxemia-derived sepsis syndrome, is characterized by endothelial dysfunction. It has been demonstrated that the endotoxin lipopolysaccharide (LPS) induces the conversion of endothelial cells (ECs) into activated fibroblasts through endothelial­to­mesenchymal transition mechanism. Fibrogenesis is highly dependent on intracellular Ca2+ concentration increases through the participation of calcium channels. However, the specific molecular identity of the calcium channel that mediates the Ca2+ influx during endotoxin-induced endothelial fibrosis is still unknown. Transient receptor potential melastatin 7 (TRPM7) is a calcium channel that is expressed in many cell types, including ECs. TRPM7 is involved in a number of crucial processes such as the conversion of fibroblasts into activated fibroblasts, or myofibroblasts, being responsible for the development of several characteristics of them. However, the role of the TRPM7 ion channel in endotoxin-induced endothelial fibrosis is unknown. Thus, our aim was to study whether the TRPM7 calcium channel participates in endotoxin-induced endothelial fibrosis. Using primary cultures of ECs, we demonstrated that TRPM7 is a crucial protein involved in endotoxin-induced endothelial fibrosis. Suppression of TRPM7 expression protected ECs from the fibrogenic process stimulated by endotoxin. Downregulation of TRPM7 prevented the endotoxin-induced endothelial markers decrease and fibrotic genes increase in ECs. In addition, TRPM7 downregulation abolished the endotoxin-induced increase in ECM proteins in ECs. Furthermore, we showed that intracellular Ca2+ levels were greatly increased upon LPS challenge in a mechanism dependent on TRPM7 expression. These results demonstrate that TRPM7 is a key protein involved in the mechanism underlying endotoxin-induced endothelial fibrosis. PMID:24710004

Echeverría, Cesar; Montorfano, Ignacio; Hermosilla, Tamara; Armisén, Ricardo; Velásquez, Luis A.; Cabello-Verrugio, Claudio; Varela, Diego; Simon, Felipe




EPA Science Inventory

SUBCHRONIC ENDOTOXIN INHALATION CAUSES CHRONIC AIRWAY DISEASE IN ENDOTOXIN-SENSITIVE BUT NOT ENDOTOXIN-RESISTANT MICE. D. M. Brass, J. D. Savov, *S. H. Gavett, ?C. George, D. A. Schwartz. Duke Univ Medical Center Durham, NC, *U.S. E.P.A. Research Triangle Park, NC, ?Univ of Iowa,...


A phosphoethanolamine transferase specific for the outer 3-deoxy-D-manno-octulosonic acid residue of Escherichia coli lipopolysaccharide. Identification of the eptB gene and Ca2+ hypersensitivity of an eptB deletion mutant.  


Addition of a phosphoethanolamine (pEtN) moiety to the outer 3-deoxy-D-manno-octulosonic acid (Kdo) residue of lipopolysaccharide (LPS) in WBB06, a heptose-deficient Escherichia coli mutant, occurs when cells are grown in 5-50 mM CaCl2 (Kanipes, M. I., Lin, S., Cotter, R. J., and Raetz, C. R. H. (2001) J. Biol. Chem. 276, 1156-1163). A Ca2+-induced, membrane-bound enzyme was responsible for the transfer of the pEtN unit to the Kdo domain. We now report the identification of the gene encoding the pEtN transferase. E. coli yhjW was cloned and overexpressed, because it is homologous to a putative pEtN transferase implicated in the modification of the beta-chain heptose residue of Neisseria meningitidis lipo-oligosaccharide (Mackinnon, F. G., Cox, A. D., Plested, J. S., Tang, C. M., Makepeace, K., Coull, P. A., Wright, J. C., Chalmers, R., Hood, D. W., Richards, J. C., and Moxon, E. R. (2002) Mol. Microbiol. 43, 931-943). In vitro assays with Kdo2-4'-[32P]lipid A as the acceptor showed that YhjW (renamed EptB) utilizes phosphatidylethanolamine in the presence of Ca2+ to transfer the pEtN group. Stoichiometric amounts of diacylglycerol were generated during the EptB-catalyzed transfer of pEtN to Kdo2-lipid A. EptB is an inner membrane protein of 574 amino acid residues with five predicted trans-membrane segments within its N-terminal region. An in-frame replacement of eptB with a kanamycin resistance cassette rendered E. coli WBB06 (but not wild-type W3110) hypersensitive to CaCl2 at 5 mM or higher. Ca2+ hypersensitivity was suppressed by excess Mg2+ in the medium or by restoring the LPS core of WBB06. The latter was achieved by reintroducing the waaC and waaF genes, which encode LPS heptosyl transferases I and II, respectively. Our data demonstrate that pEtN modification of the outer Kdo protected cells containing heptose-deficient LPS from damage by high concentrations of Ca2+. Based on its sequence similarity to EptA(PmrC), we propose that the active site of EptB faces the periplasmic surface of the inner membrane. PMID:15795227

Reynolds, C Michael; Kalb, Suzanne R; Cotter, Robert J; Raetz, Christian R H



Equine platelets inhibit E. coli growth and can be activated by bacterial lipopolysaccharide and lipoteichoic acid although superoxide anion production does not occur and platelet activation is not associated with enhanced production by neutrophils.  


Activated platelets can contribute to host defense through release of products with bactericidal actions such as antimicrobial peptides and reactive oxygen species (ROS), as well as by forming heterotypic aggregates with neutrophils and enhancing their antimicrobial properties. Whilst release of vasoactive mediators from equine platelets in response to stimuli including bacterial lipopolysaccharide (LPS) has been documented, neither ROS production, nor the effects of activated platelets on equine neutrophil ROS production, have been reported. This study first sought evidence that activated equine platelets inhibit bacterial growth. Platelet superoxide production in response to stimuli including Escherichia coli-derived LPS and lipoteichoic acid (LTA) from Staphylococcus aureus was then determined. The ability of LPS and LTA to up-regulate platelet P-selectin expression and induce platelet-neutrophil aggregate formation was investigated and the effect of co-incubating activated platelets with neutrophils on superoxide production measured. Growth of E. coli was inhibited in a time-dependent manner, and to a similar extent, by addition of platelet rich plasma (PRP) or platelet poor plasma (PPP) obtained by centrifugation of PRP. Activation of platelets in PRP by addition of thrombin led to a significant increase in the inhibitory action between 0.5 and 2h. Although phorbol myristate acetate (PMA) caused superoxide production by equine platelets in a protein kinase C-dependent manner, thrombin, platelet activating factor (PAF), LPS, LTA and formyl-methionyl-leucyl phenylalanine (FMLP) were without effect. LPS and LTA did induce platelet activation, measured as an increase in P-selectin expression (% positive cells: 17±3 (un-stimulated); 63±6 (1?g/ml LPS); 64±6 (1?g/ml LTA); n=5) but not platelet superoxide production or heterotypic aggregate formation. Co-incubation of activated platelets with neutrophils did not increase neutrophil superoxide production. This study has demonstrated for the first time that when activated, equine platelets, like those of other species, are capable of releasing ROS that could assist in bacterial killing. However, the findings suggest that neither superoxide production by platelets nor enhancement of production by neutrophils is likely to play a significant role. Nevertheless, as has been reported in man, equine PPP and PRP did inhibit E. coli growth in vitro, and addition of thrombin significantly increased the inhibitory effect of PRP. This suggests that products released from activated platelets could contribute to antimicrobial activity in the horse. The factors in equine plasma and released by activated platelets that are responsible for inhibiting bacterial growth have yet to be determined. PMID:23332730

Aktan, I; Dunkel, B; Cunningham, F M



Amelioration of endotoxin-induced uveitis treated with the sea urchin pigment echinochrome in rats  

PubMed Central

Purpose Echinochrome is a pigment present in the shells and spines of sea urchins. It has been reported to have several biologic protective effects, including in experimental models of myocardial ischemia/reperfusion injury, for which the proposed mechanisms are scavenging reactive oxygen species (ROS) and chelating iron. Endotoxin-induced uveitis (EIU) is an animal model of acute anterior segment intraocular inflammation that is induced by the injection of lipopolysaccharide (LPS). In this study, the therapeutic effect of echinochrome was examined in uveitis using the EIU model. Methods EIU was induced in Lewis rats via 200 ?g subcutaneous injections of LPS from Escherichia coli. Echinochrome was administered intravenously in 10, 1, or 0.1 mg/kg doses suspended in PBS (controls were injected with PBS only). Twenty-four hours after LPS injection, the number of infiltrating cells and the protein concentration in aqueous humor were determined. Aqueous tumor necrosis factor ? (TNF-?) concentration was quantified with enzyme-linked immunosorbent assay, eyes were stained with nuclear factor (NF) ?B antibodies, and ROS production was determined by dihydroethidium staining in fresh frozen samples. Results The number of inflammatory aqueous cells and protein levels were lower in the groups treated with 10 and 1 mg/kg of echinochrome than in the untreated LPS group (p<0.01). Treatment with 10 and 1 mg/kg of echinochrome significantly reduced TNF-? concentrations in aqueous humor (p<0.01). The numbers of NF?B-positive cells and ROS signals were also reduced by echinochrome administration (p<0.05). Conclusions Echinochrome ameliorated intraocular inflammation caused by EIU by reducing ROS production, thereby also decreasing the expression of NF?B and TNF-?. As a natural pigment, echinochrome may therefore be a promising candidate for the safe treatment of intraocular inflammation. The use of sea urchin shells and spines in health foods and medical products is thus both economically and environmentally meaningful. PMID:24520186

Kitaichi, Nobuyoshi; Noda, Kousuke; Mizuuchi, Kazuomi; Ando, Ryo; Dong, Zhenyu; Fukuhara, Junichi; Kinoshita, Satoshi; Namba, Kenichi; Ohno, Shigeaki; Ishida, Susumu



a p p l i c a t i o n n o t e Removal of endotoxin from monoclonal antibodies using VivapureTM centrifugal  

E-print Network

TM centrifugal ion exchange membrane devices Brendan Fish, Karen Bannister and Emma Tribbeck Cambridge Antibody are lipopolysaccharides present in the cell wall of most Gram- negative bacteria, and are frequently present as contaminants in protein solutions purified in research environments. Endotoxins have profound biological

Lebendiker, Mario


Treatment of Septic Patients with an Arginine-Based Endotoxin Adsorber Column Improves Hemodynamics and Reduces Oxidative Stress: Results of a Feasibility Study  

Microsoft Academic Search

Background: Mortality of severe sepsis and septic shock is unacceptably high. Adsorptive removal of endotoxin may interrupt the inflammatory cascade triggered by lipopolysaccharide. Methods: Prospective feasibility study with plasma separation and adsorption (PSA) treatment using a novel arginine-coated adsorber column was performed in a tertiary care gastroenterological intensive care unit. Results: 10 patients with severe sepsis\\/septic shock (median APACHE II

Andreas Umgelter; Wolfgang Reindl; Jens Lutz; Bernhard Kreymann; Claudio Ronco; Wolfgang Huber; Helga Frank; Roland M. Schmid; Uwe Heemann



Endotoxin Studies And Biosolids Stabilization Research  

EPA Science Inventory

This presentation has three parts; a review of bench-scale endotoxin research, a review of observations from a field scale endotoxin release study, and discussion of biosolids stabilization and characterization by PLFA/FAME microbial community analysis. Endotoxins are part of th...


Deoxynivalenol and E.coli lipopolysaccharide alter epithelial proliferation and spatial distribution of apical junction proteins along the small intestinal axis.  


We investigated a proposed synergistic effect of deoxynivalenol (DON) and lipopolysaccharides (LPS) on small intestinal architecture and epithelial barrier integrity in pigs. Crypt depth and intestinal cell proliferation were analyzed, as well as expression of zonula occludens protein-1 (ZO-1) and ?-catenin of the apical junction complex along the small intestine. Barrows (26.2±4.1 kg) were fed restrictedly either a control diet (CON) or a diet naturally contaminated with 3.1 mg DON/kg feed (DON) for 37 d. At d 37, the control group was infused for 1 h either with 100 ?g/kg BW of DON (CON-DON, n=6), 7.5 ?g/kg BW of LPS (CON-LPS, n=6), a combination of both (CON-DON+LPS, n=7), or 0.9% NaCl (CON-CON, n=6) and the DON group with 7.5 ?g/kg BW of LPS (DON-LPS, n=8) or 0.9% NaCl (DON-CON, n=6). Pigs were euthanized 3.25 h after start of infusion. Immunohistochemistry (5'-bromo-2'-deoxyuridine for proliferation) and immunofluorescence (ZO-1 and ?-catenin) from duodenum, proximal jejunum, mid-jejunum, proximal ileum, and terminal ileum were analyzed for crypt depth, cell proliferation, and apical junction proteins. Duodenal crypts were deeper compared with the other 4 intestinal regions, and proximal jejunal crypts were deeper than those of mid-jejunum and proximal ileum (P<0.001). Epithelial proliferation showed a bell-shaped distribution along the small intestinal axis. Duodenal proliferating cells had the least number compared with jejunal sections and proximal ileum (P<0.001). Neither DON nor LPS affected these variables. Zonula occludens-1 displayed a distinct spatial distribution in the epithelium with an apical and a cytosolic component. Apical expression of ZO-1 was severely damaged in the mid-jejunum (P<0.001) of CON-DON compared with animals treated with LPS. Also, in all animals receiving LPS systemically, the cytosolic ZO-1 fraction in the 3 upper gut sections disappeared completely. This effect was independent of DON presence. Control pigs had a greater basolateral ?-catenin accumulation (P<0.05) in the cells, whereas the protein distribution did not differ in CON-DON pigs. In conclusion, results of this experiment demonstrated that epithelial proliferation has a distinct pattern along the small intestine and is not necessarily positively linked to crypt depth in pigs. Furthermore, results indicate that LPS changed the spatial distribution of ZO-1. A synergistic effect of DON and LPS on intestinal architecture could not be verified in the present study. PMID:23100596

Klunker, L R; Kahlert, S; Panther, P; Diesing, A-K; Reinhardt, N; Brosig, B; Kersten, S; Dänicke, S; Rothkötter, H-J; Kluess, J W



Whole body protein deposition and plasma amino acid profiles in growing and/or finishing pigs fed increasing levels of sulfur amino acids with and without Escherichia coli lipopolysaccharide challenge.  


A split plot experiment with 72 male pigs weighing 52.9 ± 0.39 kg (mean ± SEM) was conducted to examine AA partitioning and body protein deposition (PD) in response to increasing dietary sulfur amino acids (SAA) with or without immune system (IS) activation. The main plot was with and without IS activation, and 4 diets containing different amounts of standardized ileal digestible (SID) SAA (SAA to Lys ratios of 0.45, 0.55, 0.65 and 0.75) were the subplots. Activation of IS was achieved by intramuscular injection of Escherichia coli lipopolysaccharides (LPS; serotype 055:B5, Sigma; 30 ?g/kg BW) every Monday and Thursday, with control pigs injected with sterile saline. Maximum body PD, measured by dual-energy X-ray absorptiometry (DXA), and minimum plasma urea content were achieved at SID SAA:Lys ratio of 0.55 in saline-injected pigs but were achieved at a SID SAA:Lys ratio of 0.75 in IS-activated pigs. Immune system activation increased rectal temperature (P < 0.05), plasma haptoglobin (1.1 vs. 2.0 mg/mL; P < 0.001), and the proportion of neutrophils (0.39 vs. 0.42; P < 0.05) and decreased serum albumin content (38.4 vs. 36.8 g/L; P < 0.01). Increasing dietary SAA had no effects on these variables. Immune system-activated pigs had lower levels of homocysteine (Hcy; P < 0.001) and a lower Ser content (P < 0.05). Results showed that increasing dietary SAA as DL-methionine in growing and/or finishing pigs altered plasma AA contents, and that use efficiency of the AA was improved when greater levels of SAA were supplemented in IS-activated pigs. PMID:23365380

Kim, J C; Mullan, B P; Frey, B; Payne, H G; Pluske, J R



Domain Organization of the Polymerizing Mannosyltransferases Involved in Synthesis of the Escherichia coli O8 and O9a Lipopolysaccharide O-antigens*  

PubMed Central

The Escherichia coli O9a and O8 polymannose O-polysaccharides (O-PSs) serve as model systems for the biosynthesis of bacterial polysaccharides by ATP-binding cassette transporter-dependent pathways. Both O-PSs contain a conserved primer-adaptor domain at the reducing terminus and a serotype-specific repeat unit domain. The repeat unit domain is polymerized by the serotype-specific WbdA mannosyltransferase. In serotype O9a, WbdA is a bifunctional ?-(1?2)-, ?-(1?3)-mannosyltransferase, and its counterpart in serotype O8 is trifunctional (?-(1?2), ?-(1?3), and ?-(1?2)). Little is known about the detailed structures or mechanisms of action of the WbdA polymerases, and here we establish that they are multidomain enzymes. WbdAO9a contains two separable and functionally active domains, whereas WbdAO8 possesses three. In WbdCO9a and WbdBO9a, substitution of the first Glu of the EX7E motif had detrimental effects on the enzyme activity, whereas substitution of the second had no significant effect on activity in vivo. Mutation of the Glu residues in the EX7E motif of the N-terminal WbdAO9a domain resulted in WbdA variants unable to synthesize O-PS. In contrast, mutation of the Glu residues in the motif of the C-terminal WbdAO9a domain generated an enzyme capable of synthesizing an altered O-PS repeat unit consisting of only ?-(1?2) linkages. In vitro assays with synthetic acceptors unequivocally confirmed that the N-terminal domain of WbdAO9a possesses ?-(1?2)-mannosyltransferase activity. Together, these studies form a framework for detailed structure-function studies on individual domains and a strategy applicable for dissection and analysis of other multidomain glycosyltransferases. PMID:22989876

Greenfield, Laura K.; Richards, Michele R.; Vinogradov, Evgeny; Wakarchuk, Warren W.; Lowary, Todd L.; Whitfield, Chris



Comparative studies of endotoxin uptake by isolated rat Kupffer and peritoneal cells.  

PubMed Central

The process of uptake of endotoxin by cells of the reticuloendothelial system is of current interest. Rabbit peritoneal macrophages have been used to study macrophage-endotoxin interactions and have suggested a receptor-mediated process. It is generally believed that the site of in vivo endotoxin clearance is the liver and that this clearance involves the Kupffer cell population. In the current report, the uptake characteristics of iodine-125-labeled Salmonella minnesota lipopolysaccharide (LPS) were compared in both isolated rat Kupffer cells and elicited rat peritoneal cells. Both types of cells were isolated from male Sprague-Dawley rats fed a semisynthetic AIN-76 5% saturated-fat diet either by peritoneal lavage for peritoneal cells or by collagenase perfusion followed by purification on a 17.5% metrizamide gradient for Kupffer cells. Hot phenol water-extracted S. minnesota LPS was labeled with iodine by the chloramine-T method following a reaction with methyl-p-hydroxybenzimidate. The in vitro uptake of [125I]LPS by Kupffer cells was unsaturable up to concentrations of 33.33 micrograms/ml, while peritoneal cells became saturated at between 16.67 and 25 micrograms of LPS per ml. Uptake by both types of cells could be inhibited by a 10-fold excess of unlabeled LPS. Kinetic experiments demonstrated that Kupffer cells were unsaturable after 60 min of incubation, while peritoneal cells were saturable after 40 min of incubation. Pretreatment with 75 mM colchicine inhibited uptake by peritoneal cells but not Kupffer cells, while pretreatment with 12 mM 2-deoxyglucose inhibited uptake by Kupffer cells but not peritoneal cells. These results are consistent with a process of receptor-mediated endocytosis for peritoneal cells, while Kupffer cells may internalize endotoxins by absorptive pinocytosis. These results suggest that studies of peritoneal cell-endotoxin interactions do not accurately describe the physiologic process within the liver, the major site for the clearance of gut-derived endotoxins. PMID:2824379

Fox, E S; Thomas, P; Broitman, S A



Immobilization of ?-polylysine onto the probe surface for molecular adsorption type endotoxin detection system  

NASA Astrophysics Data System (ADS)

Patients with renal failure become not able to expel the waste product, and they accumulate the toxic products for themselves. They therefore must use the hemodialysis to weed out the metabolic decomposition product. Hemodialysis for chronic renal failure is the most popular treatment method with artificial organs. However, hemodialysis patients must continue the treatment throughout their life, the results of long term extracorporeal dialysis, those patients develop the various complications and diseases, for example, dialysis amyloidosis etc. Dialysis amyloidosis is one of the refractory complications, and the prevention of this complication is important. Recently, endotoxin is thought to be the most likely cause of the complication. Endotoxin is one of the major cell wall components of gram-negative bacteria, and it forms the complex with proteins and lipopolysaccharide (LPS). It has various biological activities, e.g. attack of fever, when it gets mixed into human blood. In addition, it is known that large amount of endotoxin exists in living environment, and medicine is often contaminated with endotoxin. When contaminated dialyzing fluids are used to hemodialysis, above-mentioned dialysis amyloidosis is developed. Therefore, it is important that the detection and removal of endotoxin from dialyzing fluids. Until now, the measurement methods using Limulus Amebosyte Lysate (LAL) reagent were carried out as the tests for the presence of endotoxin. However, these methods include several different varieties of measurement techniques. The following are examples of them, gelatinization method, turbidimetric assay method, colorimetric assay method and fluoroscopic method. However, these techniques needed 30-60 minutes for the measurement. From these facts, they are not able to use as a "real-time endotoxin detector". The detection of endotoxin has needed to carry out immediately, for that reason, a new "real-time" detection method is desired. We focused attention to adsorption reaction between ?-polylysine and endotoxin. ?-polylysine has the structure of straight chain molecule composed by 25-30 residues made by lysine, and it is used as an antimicrobial agent, moreover, cellulose beads with immobilized ?-polylysine is used as the barrier filter for endotoxin removal. Therefore, it is expected that the endotoxin be adsorbed to the immobilized ?-polylysine onto the probe. As the result of this reaction, the mass of the probe is increased, and endotoxin can be detected by using of Quartz Crystal Microbalance (QCM). In our previous research, we have already acquired the proteins immobilization technique onto Au and Si surface. In this report, the proposal of molecular adsorption type endotoxin detection system, and the immobilization of ?-polylysine onto the probe are described. We use X-ray Photoelectron Spectroscopy (XPS) to confirm the ?-polylysine immobilization, and the adsorptive activity of immobilized ?-polylysine is measured by XPS and AFM. The purpose of this study is to bring about the realization of "Real-time endotoxin detection system".

Ooe, Katsutoshi; Tsuji, Akihito; Nishishita, Naoki; Hirano, Yoshiaki



Escherichia coli Morphological Changes and Lipid A Removal Induced by Reduced Pressure Nitrogen Afterglow Exposure  

PubMed Central

Lipid A is a major hydrophobic component of lipopolysaccharides (endotoxin) present in the membrane of most Gram-negative bacteria, and the major responsible for the bioactivity and toxicity of the endotoxin. Previous studies have demonstrated that the late afterglow region of flowing post-discharges at reduced pressure (1-20 Torr) can be used for the sterilization of surfaces and of the reusable medical instrumentation. In the present paper, we show that the antibacterial activity of a pure nitrogen afterglow can essentially be attributed to the large concentrations of nitrogen atoms present in the treatment area and not to the UV radiation of the afterglow. In parallel, the time variation of the inactivation efficiency quantified by the log reduction of the initial Escherichia coli (E. coli) population is correlated with morphologic changes observed on the bacteria by scanning electron microscopy (SEM) for increasing afterglow exposure times. The effect of the afterglow exposure is also studied on pure lipid A and on lipid A extracted from exposed E. coli bacteria. We report that more than 60% of lipid A (pure or bacteria-extracted) are lost with the used operating conditions (nitrogen flow QN2 = 1 standard liter per minute (slpm), pressure p = 5 Torr, microwave injected power PMW = 200 W, exposure time: 40 minutes). The afterglow exposure also results in a reduction of the lipid A proinflammatory activity, assessed by the net decrease of the redox-sensitive NF?B transcription factor nuclear translocation in murine aortic endothelial cells stimulated with control vs afterglow-treated (pure and extracted) lipid A. Altogether these results point out the ability of reduced pressure nitrogen afterglows to neutralize the cytotoxic components in Gram-negative bacteria. PMID:25837580

Zerrouki, Hayat; Rizzati, Virginie; Bernis, Corinne; Nčgre-Salvayre, Anne; Sarrette, Jean Philippe; Cousty, Sarah



Preparation, characterization, and immunological properties in mice of Escherichia coli O157 O-specific polysaccharide-protein conjugate vaccines.  

PubMed Central

Escherichia coli O157 causes severe enteritis and the extraintestinal complication of hemolytic-uremic syndrome, with their highest incidence occurring in children. We postulated that serum immunoglobulin G (IgG) antibodies to the O-specific polysaccharide of lipopolysaccharide (LPS) may confer protective immunity to enteric pathogens by inducing bactericidal reactions against the ingested organisms in the jejunum (J. B. Robbins, C. Chu, and R. Schneerson, Clin. Infect. Dis. 15:346-361, 1992; S. C. Szu, R. Gupta, and J. B. Robbins, p. 381-394, in I. K. Wachsmuth, P. A. Blake, and O. Olsvik, ed., Vibrio cholerae, 1994). Because polysaccharide-protein conjugates induce serum IgG antibodies in infants, we bound the O-specific polysaccharide of E. coli O157 to proteins. E. coli O157 LPS, treated with acetic acid or hydrazine, was derivatized with adipic acid dihydrazide and bound to proteins by carbodiimide-mediated condensation. Conjugates of these adipic hydrazide derivative were prepared with bovine serum albumin, formalin-treated exotoxin C of Clostridium welchii (Pig Bel toxoid), or Pseudomonas aeruginosa recombinant exoprotein A. The conjugates had low levels of endotoxin and elicited serum antibodies with bactericidal activity to the O157 LPS. The largest increase in LPS antibodies was of the IgG class. Clinical evaluation of E. coli O157-toxoid conjugates is planned. Images PMID:7927787

Konadu, E; Robbins, J B; Shiloach, J; Bryla, D A; Szu, S C



Characterization of murine monoclonal antibodies to Escherichia coli J5.  

PubMed Central

Twenty-eight independently derived monoclonal antibodies (MAb) directed against Escherichia coli J5 endotoxin were produced and characterized. Each MAb exhibited a specific titer by both radioimmunoassay and passive hemagglutination assay. Most of the MAb were of the immunoglobulin G isotype; however, several immunoglobulin M antibodies and one immunoglobulin A antibody were produced. When characterized for their capacity to cross-react with purified endotoxin preparations from several gram-negative bacteria, 22 MAb exhibited no cross-reactivity; 6 demonstrated a limited capacity to cross-react with other endotoxin preparations. When characterized for their capacity to react with the intact organism instead of the purified endotoxin the pattern of cross-reactivity was quite different. Most of the MAb were able to react with Salmonella minnesota Re595. Eighteen were able to react with E. coli O111:B4 (the parent strain of E. coli J5), 13 MAb reacted weakly with Pseudomonas aeruginosa, and 3 reacted weakly with Klebsiella pneumonia. The data imply that MAb generated against E. coli J5 endotoxin demonstrate greater cross-reactivity when assayed against the whole bacterium than when assayed against the corresponding purified endotoxin. We were unable to demonstrate that any of the 28 MAb could passively protect mice against lethal endotoxin challenge. PMID:3514463

Miner, K M; Manyak, C L; Williams, E; Jackson, J; Jewell, M; Gammon, M T; Ehrenfreund, C; Hayes, E; Callahan, L T; Zweerink, H



Role for macrophage products in endotoxin-induced polymorphonuclear leukocyte accumulation during inflammation.  


Endotoxins (lipopolysaccharide, LPS) released by Gram-negative bacteria induce acute inflammation with polymorphonuclear leukocyte (PMNL) infiltration. The mechanism of PMNL accumulation appears to be complement-independent and is not well understood. Here, we report investigation of the factors which may mediate LPS-induced PMNL accumulation in the pleural cavity and skin of rabbits. The intrapleural injection of 50 ng of Escherichia coli 0111 LPS caused the appearance in the exudate fluid of an activity which, upon intradermal injection induced PMNL accumulation in the skin, as measured by a 51Cr-labeled leukocyte assay and which was confirmed histologically. This activity preceded by 30 minutes the massive influx of PMNL into the pleural cavity. 125I-labeled LPS, gel filtration chromatography, limulus amebocyte lysate assays, and polymyxin B allowed distinction between reactions in the skin attributable to LPS and reactions due to the effect of this "PMNL infiltration-inducing activity." Pleural macrophages cultured for 3 to 6 hours with 3 to 30 ng/ml of LPS also released factors which induced PMNL infiltration into the skin. Sephadex G-100 chromatography of LPS-induced pleural exudate fluid or of supernatants from LPS-stimulated macrophage cultures yielded identical elution profiles, with one major peak of PMNL infiltration-inducing activity at an apparent molecular weight of 45,000 and a minor peak at 14,000 to 18,000. Only the low molecular weight fraction contained interleukin 1 activity. Lipid A was required for the secretion of these factors by macrophages. The LPS shed by killed E. coli also induced macrophage production of PMNL infiltration-inducing activity. The activity was sensitive to pronase, and its production was inhibited by an inhibitor of protein synthesis (cycloheximide). The active factors did not induce PMNL chemotaxis, aggregation, or chemiluminescence in vitro indicating that the activity was not C5a. We conclude that PMNL infiltration induced by LPS and perhaps by Gram-negative bacteria, may be mediated in part by the secretion from tissue macrophages of factors which can recruit PMNLs from the blood. The most active of these (approximately equal to 45,000 daltons) lacks interleukin-1 or PMNL chemotactic activity. PMID:3491929

Issekutz, A C; Megyeri, P; Issekutz, T B



Epigenetic mechanisms contribute to enhanced expression of immune response genes in the liver of cows after experimentally induced Escherichia coli mastitis.  


Endotoxins, such as lipopolysaccharide (LPS), are released during infection with Gram-negative bacteria, which can result in excessive activation of toll-like receptor (TLR) signalling. The aim of the present study was to investigate whether epigenetic mechanisms are involved in controlling the onset and progression of the systemic inflammatory response. Using chromatin accessibility by real-time (CHART) PCR to assess livers from cows with experimentally induced Escherichia coli mastitis, this study demonstrated that the chromatin at the site of the promoters of the genes encoding TLR2, TLR4, lipopolysaccharide binding protein (LBP) and haptoglobin (HP) was opened up 24 h after infection, accompanied by enhanced mRNA expression by these genes. Such modulation did not occur in the same samples for the ?S1-casein promoter, which served as a negative control. Demethylation of the TLR4 promoter accompanied opening up of chromatin. These data suggest that modulation of epigenetic factors might offer a novel approach to treating adverse systemic reactions elicited in cows with E. coli mastitis. PMID:25618856

Chang, Guangjun; Petzl, Wolfram; Vanselow, Jens; Günther, Juliane; Shen, Xiangzhen; Seyfert, Hans-Martin



PHYSIOLOGY, ENDOCRINOLOGY, AND REPRODUCTION Analysis of Plasma Serotonin Levels and Hemodynamic Responses Following Chronic Serotonin Infusion in Broilers Challenged with Bacterial Lipopolysaccharide and Microparticles1  

Microsoft Academic Search

There has been extensive interest in the role of serotonin (5-hydoxytryptamine, 5-HT) in the pathogenesis of pulmonary hypertension because epi- sodes of pulmonary arterial hypertension in humans have been linked to serotoninergic appetite-suppressant drugs. In this study, we investigated the role of serotonin in the development of pulmonary hypertension induced by intravenously injecting bacterial lipopolysaccharide (LPS, endotoxin) and cellulose microparticles.

M. E. Chapman; R. L. Taylor; R F. Wideman Jr


Interaction of Antimicrobial Peptide Temporin L with Lipopolysaccharide In Vitro and in Experimental Rat Models of Septic Shock Caused by Gram-Negative Bacteria  

Microsoft Academic Search

Sepsis remains a major cause of morbidity and mortality in hospitalized patients, despite intense efforts to improve survival. The primary lead for septic shock results from activation of host effector cells by endotoxin, the lipopolysaccharide (LPS) associated with cell membranes of gram-negative bacteria. For these reasons, the quest for compounds with antiendotoxin properties is actively pursued. We investigated the efficacy

Andrea Giacometti; Oscar Cirioni; Roberto Ghiselli; Federico Mocchegiani; Fiorenza Orlando; Carmela Silvestri; Argante Bozzi; A. Di Giulio; C. Luzi; M. L. Mangoni; D. Barra; V. Saba; G. Scalise; A. C. Rinaldi



Time-dependent enhancement or inhibition of endotoxin-induced vascular injury in rat intestine by nitric oxide synthase inhibitors.  

PubMed Central

1. The effects of the nitric oxide (NO) synthase inhibitors, NG-nitro-L-arginine methyl ester (L-NAME) and NG-monomethyl-L-arginine (L-NMMA), on the vascular damage induced by the endotoxin, E. coli lipopolysaccharide (LPS), in the ileum and colon were investigated in the conscious rat over a 5 h period. 2. Administration of LPS (3 mg kg-1, i.v.) increased ileal and colonic vascular injury after a lag period of 2 h, as determined by the leakage of radiolabelled albumin. 3. Administration of L-NAME (1-5 mg kg-1, s.c.) concurrently with LPS, produced a dose-dependent increase in vascular albumin leakage in the intestinal tissues, when determined over a 5 h period. Vascular albumin leakage with LPS and L-NAME (5 mg kg-1) was substantially increased after 1 h, reached maximal levels 3 h after administration, and then slowly declined. 4. L-NMMA (50 mg kg-1, s.c.), likewise elevated intestinal albumin leakage when administered concurrently with LPS, but this reached maximal levels after 1 h and rapidly declined over the subsequent 2 h. 5. In control rats, in the absence of LPS challenge, neither L-NAME (5 mg kg-1, s.c.) nor L-NMMA (50 mg kg-1, s.c.) increased intestinal vascular leakage of albumin over a 5 h period. 6. By contrast, when L-NAME (1-5 mg kg-1, s.c.) or L-NMMA (12.5-50 mg kg-1, s.c.) was injected 3 h after LPS, a dose-dependent reduction in the LPS-provoked vascular albumin leakage was observed.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7518298

Laszlo, F.; Whittle, B. J.; Moncada, S.



Inhibition of IRAK-4 activity for rescuing endotoxin LPS-induced septic mortality in mice by lonicerae flos extract  

SciTech Connect

Highlights: •Lonicerae flos extract (HS-23) is a clinical candidate, Phase I for sepsis treatment. •Here, HS-23 or its major constituents rescued LPS-induced septic mortality in mice. •As a mechanism, they directly inhibited IRAK-4-catalyzed kinase activity. •Thus, they suppressed LPS-induced expression of NF-?B/AP-1-target inflammatory genes. -- Abstract: Lonicerae flos extract (HS-23) is a clinical candidate currently undergoing Phase I trial in lipopolysaccharide (LPS)-injected healthy human volunteers, but its molecular basis remains to be defined. Here, we investigated protective effects of HS-23 or its major constituents on Escherichia coli LPS-induced septic mortality in mice. Intravenous treatment with HS-23 rescued LPS-intoxicated C57BL/6J mice under septic conditions, and decreased the levels of cytokines such as tumor necrosis factor ? (TNF-?), interleukin (IL)-1? and high-mobility group box-1 (HMGB-1) in the blood. Chlorogenic acid (CGA) and its isomers were assigned as major constituents of HS-23 in the protection against endotoxemia. As a molecular mechanism, HS-23 or CGA isomers inhibited endotoxin LPS-induced autophosphorylation of the IL-1 receptor-associated kinase 4 (IRAK-4) in mouse peritoneal macrophages as well as the kinase activity of IRAK-4 in cell-free reactions. HS-23 consequently suppressed downstream pathways critical for LPS-induced activation of nuclear factor (NF)-?B or activating protein 1 (AP-1) in the peritoneal macrophages. HS-23 also inhibited various toll-like receptor agonists-induced nitric oxide (NO) production, and down-regulated LPS-induced expression of NF-?B/AP-1-target inflammatory genes in the cells. Taken together, HS-23 or CGA isomers exhibited anti-inflammatory therapy against LPS-induced septic mortality in mice, at least in part, mediated through the inhibition of IRAK-4.

Park, Sun Hong; Roh, Eunmiri [College of Pharmacy, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)] [College of Pharmacy, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Kim, Hyun Soo [Pharmaceutical R and D Center, Huons Co., Ltd., Anyang (Korea, Republic of)] [Pharmaceutical R and D Center, Huons Co., Ltd., Anyang (Korea, Republic of); Baek, Seung-Il [College of Pharmacy, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)] [College of Pharmacy, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Choi, Nam Song [Pharmaceutical R and D Center, Huons Co., Ltd., Anyang (Korea, Republic of)] [Pharmaceutical R and D Center, Huons Co., Ltd., Anyang (Korea, Republic of); Kim, Narae; Hwang, Bang Yeon; Han, Sang-Bae [College of Pharmacy, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)] [College of Pharmacy, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Kim, Youngsoo, E-mail: [College of Pharmacy, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)] [College of Pharmacy, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)



The isolation and characterization of lipopolysaccharides from Microcystis aeruginosa, a prominent toxic water bloom forming cyanobacteria.  


Massive toxic blooms of cyanobacteria represent a major threat to water supplies worldwide, yet serious gaps exist in understanding their complex toxic effects, including the role of lipopolysaccharides (LPS). The present comparative study focused on the levels and biological activities of LPS isolated from Microcystis aeruginosa, which is one of the most globally distributed toxic species. Using hot phenol extraction, LPS was isolated from 3 laboratory cultures and 11 natural water blooms. It formed 0.2-0.7% of the original dry biomass of the cyanobacteria, based on gravimetry. Additional analyses by commercial anti-LPS ELISA were correlated with gravimetry but showed concentrations that were about 7-times lower, which indicated either impurities in isolated LPS or the poor cross-reactivity of the antibodies used. LPS isolates from M. aeruginosa were potent pyrogens in the traditional Limulus amebocyte lysate (LAL)-test, but comparison with the PyroGene test demonstrated the limited selectivity of LAL with several interferences. The determined pyrogenicity (endotoxin units, EU) ranged from very low values in laboratory cultures (less than 0.003 up to 0.008-EU per 100 pg LPS) to higher values in complex bloom samples (0.01-0.078 EU per 100 pg of LPS), which suggested the role of bloom-associated bacteria in the overall effects. Potent pro-inflammatory effects of the studied LPS from both cultures and bloom samples were observed in a highly-relevant ex vivo human blood model by studying reactive oxygen species production in phagocytes as well as increased productions of interleukin 8, IL-8, and tumor necrosis factor ?, TNF-?. LPS from M. aeruginosa seem to modulate several pathways involved in the regulation of both innate immunity and specific responses. In comparison to the standard pathogenic bacterial LPS (World Health Organization Escherichia coli O113:10 endotoxin; activity 1 EU per 100 pg), the studied cyanobacterial samples had pyrogenicity potencies that were at least 12-times lower. However, the health risks associated with LPS from M. aeruginosa should not be underestimated, especially with respect to diverse biological effects observed ex vivo and in the case of massive blooms in drinking water reservoirs, where the estimated pyrogenicity can reach up to 46,000 EU per mL of water. PMID:24140921

Bláhová, Lucie; Adamovský, Ond?ej; Kubala, Lukáš; Švihálková Šindlerová, Lenka; Zounková, Radka; Bláha, Lud?k



Lipopolysaccharide Sequestrants: Structural Correlates of Activity and Toxicity in Novel Acylhomospermines  

PubMed Central

Lipopolysaccharides (LPS), otherwise termed ‘endotoxins’, are outer-membrane constituents of Gram-negative bacteria. Lipopolysaccharides play a key role in the pathogenesis of ‘Septic Shock’, a major cause of mortality in the critically ill patient. Therapeutic options aimed at limiting downstream systemic inflammatory processes by targeting lipopolysaccharide do not exist at the present time. We have defined the pharmacophore necessary for small molecules to specifically bind and neutralize LPS and, using animal models of sepsis, have shown that the sequestration of circulatory LPS by small molecules is a therapeutically viable strategy. In this paper, the interactions of a series of acylated homologated spermine compounds with lipopolysaccharide (LPS) have been characterized. The optimal acyl chain length for effective sequestration of LPS was identified to be C16 for the mono-acyl compounds. The most promising of these compounds, 4e, binds LPS with an ED50 of 1.37 ?M. Nitric oxide production in murine J774A.1 cells, as well as TNF-? in human blood, are inhibited in a dose-dependent manner by 4e at concentrations orders of magnitude lower than toxic doses. Administration of 4e to d-galactosamine-sensitized mice challenged with supralethal doses of LPS provided significant protection against lethality. Potent anti-endotoxic activity, low toxicity, and ease of synthesis render this class of compounds candidate endotoxin-sequestering agents of potential significant therapeutic value. PMID:15801849

Miller, Kelly A.; Kumar, E.V.K. Suresh; Wood, Stewart J.; Cromer, Jens R.; Datta, Apurba; David*, Sunil A.



Stimulation and release of prostaglandins and thromboxane from macrophages by cotton dust associated lipopolysaccharides.  


Decreases in the ventilation capacity of human lungs following the inspiration of cotton dust correlates more closely with the concentration of endotoxin in the dust than with any other parameter measured thus far. A lipopolysaccharide isolated from the endotoxin of Enterobacter agglomerans, a common bacterial contaminant of cotton fiber, stimulated isolated rat macrophages to produce and release prostaglandins 6 keto-PGF1 alpha, PGF2 alpha, PGE2, PGD2, PGA2, and PGB2 and thromboxane B2. If in vivo human pulmonary macrophages respond in a similar fashion by releasing these arachidonic acid metabolites or their immediate precursors in response to stimulation by cotton dust associated lipopolysaccharides, some of the acute pulmonary changes observed in humans following inspiration of cotton dust could be caused by increased release of these biologically active compounds. Daily release of arachidonic acid metabolites at concentrations significantly above normal homeostatic levels could produce some of the pathophysiologic pulmonary changes observed in byssinotics. This paper reports the results of an experiment to quantitate arachidonic acid metabolite production following macrophage stimulation by E. agglomerans lipopolysaccharide. Procedures are described for the stimulation of macrophages by cotton dust associated lipopolysaccharide, for the separation and identification of arachidonic acid and its metabolites by high-performance liquid chromatography, and for the quantification of those products by radioisotope techniques. PMID:2270833

Elissalde, M H; Beier, R C



Longitudinal Study of Dust and Airborne Endotoxin in the Home  

Microsoft Academic Search

within-home variance) in endotoxin level to improve assessment of exposure to endotoxin at home. However, there are no previous reports of the within- and between-home variance components of endotoxin. In this study we measured dust endotox- in in 20 homes and airborne endotoxin in 15 of those homes at monthly intervals for up to 13 months. With these repeated measure-

Ju-Hyeong Park; Donna L. Spiegelman; Harriet A. Burge; Diane R. Gold; Ginger L. Chew; Donald K. Milton



Kinetics of nitric oxide synthase induction by Propionibacterium avidum and lipopolysaccharide.  


Conditions for the induction of rat liver Ca2(+)-independent nitric oxide synthase were determined with killed Propionibacterium avidum, and compared with lipopolysaccharide endotoxin. Similar maximal induction was obtained intraperitoneally with the two types of inducers but killed Propionibacterium avidum gave a long-lasting induction while lipopolysaccharide displayed a rapid and short response. Moreover, the induction resulting from an intravenous administration of killed Propionibacterium avidum reached 60 times that of the control whereas lipopolysaccharide treatment induced a 24-fold stimulation only. It is noteworthy that with the first inducer the nitric oxide activity was stable with time whereas with the second one it dropped after 8 h. Whatever the route of administration of killed Propionibacterium avidum, some huge vacuolated Kupffer cells were found in the liver whose parenchyma was almost normal. Numerous monocytes, and unaltered Kupffer cells, were observed. Kupffer cells were identified to be responsible for the uptake of killed Propionibacterium avidum. PMID:8748697

Dhouib, M; Gendrault, J L; Lugnier, A A



Elements of the Endotoxin Theory of Human Physiology and Pathology  

Microsoft Academic Search

The involvement of intestinal flora endotoxin (ET) in the regulation of immune homeostasis, namely, the maintenance of the physiological tone of all components of the immune system (so-called systemic endotoxinemia, SEE) is postulated. Excessive endotoxin in the systemic blood flow under conditions of the failure of endotoxin-binding and endotoxin-eliminating systems results in another phenomenon, endotoxin aggression (EA), which is regarded

M. Yu. Yakovlev



Novel Bacillus thuringiensis ?-Endotoxin Active against Locusta migratoria manilensis ?  

PubMed Central

A novel ?-endotoxin gene was cloned from a Bacillus thuringiensis strain with activity against Locusta migratoria manilensis by PCR-based genome walking. The sequence of the cry gene was 3,432 bp long, and it encoded a Cry protein of 1,144 amino acid residues with a molecular mass of 129,196.5 kDa, which exhibited 62% homology with Cry7Ba1 in the amino acid sequence. The ?-endotoxin with five conserved sequence blocks in the amino-terminal region was designated Cry7Ca1 (GenBank accession no. EF486523). Protein structure analysis suggested that the activated toxin of Cry7Ca1 has three domains: 227 residues forming 7 ?-helices (domain I); 213 residues forming three antiparallel ?-sheets (domain II); and 134 residues forming a ?-sandwich (domain III). The three domains, respectively, exhibited 47, 44, and 34% sequence identity with corresponding domains of known Cry toxins. SDS-PAGE and Western blot analysis showed that Cry7Ca1, encoded by the full-length open reading frame of the cry gene, the activated toxin 1, which included three domains but without the N-terminal 54 amino acid residues and the C terminus, and the activated toxin 2, which included three domains and N-terminal 54 amino acid residues but without the C terminus, could be expressed in Escherichia coli. Bioassay results indicated that the expressed proteins of Cry7Ca1 and the activated toxins (toxins 1 and 2) showed significant activity against 2nd instar locusts, and after 7 days of infection, the estimated 50% lethal concentrations (LC50s) were 8.98 ?g/ml for the expressed Cry7Ca1, 0.87 ?g/ml for the activated toxin 1, and 4.43 ?g/ml for the activated toxin 2. The ?-endotoxin also induced histopathological changes in midgut epithelial cells of adult L. migratoria manilensis. PMID:21441319

Wu, Yan; Lei, Cheng-Feng; Yi, Dan; Liu, Peng-Ming; Gao, Mei-Ying



Distribution and Kinetics of Lipoprotein-Bound Endotoxin  

PubMed Central

Lipopolysaccharide (LPS), the major glycolipid component of gram-negative bacterial outer membranes, is a potent endotoxin responsible for pathophysiological symptoms characteristic of infection. The observation that the majority of LPS is found in association with plasma lipoproteins has prompted the suggestion that sequestering of LPS by lipid particles may form an integral part of a humoral detoxification mechanism. Previous studies on the biological properties of isolated lipoproteins used differential ultracentrifugation to separate the major subclasses. To preserve the integrity of the lipoproteins, we have analyzed the LPS distribution, specificity, binding capacity, and kinetics of binding to lipoproteins in human whole blood or plasma by using high-performance gel permeation chromatography and fluorescent LPS of three different chemotypes. The average distribution of O111:B4, J5, or Re595 LPS in whole blood from 10 human volunteers was 60% (±8%) high-density lipoprotein (HDL), 25% (±7%) low-density lipoprotein, and 12% (±5%) very low density lipoprotein. The saturation capacity of lipoproteins for all three LPS chemotypes was in excess of 200 ?g/ml. Kinetic analysis however, revealed a strict chemotype dependence. The binding of Re595 or J5 LPS was essentially complete within 10 min, and subsequent redistribution among the lipoprotein subclasses occurred to attain similar distributions as O111:B4 LPS at 40 min. We conclude that under simulated physiological conditions, the binding of LPS to lipoproteins is highly specific, HDL has the highest binding capacity for LPS, the saturation capacity of lipoproteins for endotoxin far exceeds the LPS concentrations measured in clinical situations, and the kinetics of LPS association with lipoproteins display chemotype-dependent differences. PMID:11292694

Levels, J. H. M.; Abraham, P. R.; van den Ende, A.; van Deventer, S. J. H.



Biophysical analysis of the interaction of granulysin-derived peptides with enterobacterial endotoxins  

PubMed Central

To combat infections by Gram-negative bacteria, it is not only necessary to kill the bacteria but also to neutralize pathogenicity factors such as endotoxin (lipopolysaccharide, LPS). The development of antimicrobial peptides based on mammalian endotoxin-binding proteins is a promising tool in the fight against bacterial infections, and septic shock syndrome. Here, synthetic peptides derived from granulysin (Gra-pep) were investigated in microbiological and biophysical assays to understand their interaction with LPS. We analyzed the influence of the binding of Gra-pep on (1) the acyl chain melting of the hydrophobic moiety of LPS, lipid A, by Fourier-transform spectroscopy, (2) the aggregate structure of LPS by small-angle X-ray scattering and cryo-transmission electron microscopy, and 3) the enthalpy change by isothermal titration calorimetry. In addition, the influence of Gra-pep on the incorporation of LPS and LPS-LBP (lipopolysaccharide-binding protein) complexes into negatively charged liposomes was monitored. Our findings demonstrate a characteristic change in the aggregate structure of LPS into multilamellar stacks in the presence of Gra-pep, but little or no change of acyl chain fluidity. Neutralization of LPS by Gra-pep is not due to a scavenging effect in solution, but rather proceeds after incorporation into target membranes, suggesting a requisite membrane-bound step. PMID:17555705

Chen, Xi; Howe, Jörg; Andrä, Jörg; Rössle, Manfred; Richter, Walter; Silva, Ana Paula Galvăo da; Krensky, Alan M.; Clayberger, Carol; Brandenburg, Klaus



?-hydroxymyristic acid as a chemical marker to detect endotoxins in dialysis water.  


An analytical chemical method has been developed for determination of ?-hydroxymyristic acid (?-HMA), a component of lipopolysaccharides (LPSs/endotoxins) in dialysis water. In our investigation, the ?-HMA component was used as a chemical marker for endotoxin presence in dialysis water because it is available in the molecular subunit (lipid A) and responsible for toxicity. It is the most abundant saturated fatty acid in that subunit. The developed method is based on fluorescence derivatization with 4-nitro-7-piperazino-2,1,3-benzoxadiazole (NBD-PZ). A high-performance liquid chromatographic separation of the ?-HMA derivative was achieved using an octadecyl silica column in gradient elution. A wide dynamic range of ?-HMA was tested and a calibration curve was constructed with accuracy of 90% and variability of less than 10%. The limits of detection and quantification obtained were 2 and 5?M, respectively. The developed method was applied to detect endotoxins in dialysis water by alkaline hydrolysis of LPS using NaOH (0.25M) at 60°C for 2h. After hydrolysis, free acid was detected as its NBD-PZ derivative using high-performance liquid chromatography/mass spectrometry (HPLC/MS). Good recovery rates ranging from 98 to 105% were obtained for ?-HMA in dialysis water. PMID:25449302

Mishra, Rupesh K; Robert-Peillard, Fabien; Ravier, Sylvain; Coulomb, Bruno; Boudenne, Jean-Luc



Human serum amyloid P component attenuates the bacterial lipopolysaccharide-induced increase in blood–brain barrier permeability in mice  

Microsoft Academic Search

Endotoxin challenge leads to septic shock, multi-organ failure and death in mice. Permeability of the blood–brain barrier (BBB) is increased by endotoxemia. Serum amyloid P component (SAP) is a lipopolysaccharide (LPS)-binding protein that can modulate the host reactions during infections. It is controversial whether SAP can protect from LPS toxicity in vivo or not. We have tested the effect of

Szilvia Veszelka; Zoltán Urbányi; Tamás Pázmány; László Németh; Izabella Obál; Ngo Thi Khue Dung; Csongor S. Ábrahám; Gábor Szabó; Mária A. Deli



Septin: A Factor in Plasma That Opsonizes Lipopolysaccharide-bearing Particles for Recognition by CD14 on Phagocytes  

Microsoft Academic Search

SnmmJary We have previously reported that lipopolysaccharide (LPS) binding protein (LBP) opsonizes endotoxin (LPS) for recognition by CD14 on phagocytes. Here we show that normal human plasma contains high titers of an activity that also binds LPS (Re, 595) and mediates recognition by CD14. Opsonization of LPS-coated particles with plasma enables the particles to be bound by phagocytes. Further, opsonization

Samuel D. Wright; Mayuri Patel; David S. Miller


Analysis of endotoxin effects on pulmonary circulation in terms of pressure-flow characteristics.  


The purpose of the present work was to explore the hypothesis that pulmonary vasoconstriction secondary to endotoxin insult results mainly from an increase in the critical closing pressure of the pulmonary vessels. Specifically, we reasoned that in the face of a Starling resistor located between pulmonary arteries and left atrium, upstream transmission of increased left atrial pressure (Pla) would be inversely related to the level of the pressure intercept (Pi) obtained by extrapolation from the linear pulmonary arterial pressure (Ppa)--flow (Q degrees) plot. Six dogs (group E) were infused with Escherichia coli endotoxin (0.25 microgram/kg/min) for 2 hr, whereas six additional dogs (group C) served as control. During baseline conditions, Pi approximated LAP in both groups. In group C dogs, increasing LAP at constant Q degrees led to a proportional augmentation of Ppa. In group E dogs, endotoxin resulted in a shift of the Ppa-Q relationships to higher pressures due to both increases in Pi and slope. In addition, changes in Pla over the same range as in control dogs affected Ppa only at the highest levels of Pla. We conclude that endotoxin insult increases the critical closing pressure that exceeds Pla and induces the occurrence of a Starling resistor responsible for the production of an effective vascular waterfall. PMID:8485820

D'Orio, V; Fatemi, M; Marnette, J M; Fossion, A; Marcelle, R



Effect of Zingiber officinale and propolis on microorganisms and endotoxins in root canals  

PubMed Central

The purpose of this study was to evaluate the effectiveness of glycolic propolis (PRO) and ginger (GIN) extracts, calcium hydroxide (CH), chlorhexidine (CLX) gel and their combinations as ICMs (ICMs) against Candida albicans, Enterococcus faecalis, Escherichia coli and endotoxins in root canals. Material and Methods: After 28 days of contamination with microorganisms, the canals were instrumented and then divided according to the ICM: CH+saline; CLX, CH+CLX, PRO, PRO+CH; GIN; GIN+CH; saline. The antimicrobial activity and quantification of endotoxins by the chromogenic test of Limulus amebocyte lysate were evaluated after contamination and instrumentation at 14 days of ICM application and 7 days after ICM removal. Results and Conclusion: After analysis of results and application of the Kruskal-Wallis and Dunn statistical tests at 5% significance level, it was concluded that all ICMs were able to eliminate the microorganisms in the root canals and reduce their amount of endotoxins; however, CH was more effective in neutralizing endotoxins and less effective against C. albicans and E. faecalis, requiring the use of medication combinations to obtain higher success. PMID:23559108

MAEKAWA, Lilian Eiko; VALERA, Marcia Carneiro; de OLIVEIRA, Luciane Dias; CARVALHO, Cláudio Antonio Talge; CAMARGO, Carlos Henrique Ribeiro; JORGE, Antonio Olavo Cardoso



Detoxification of endotoxin by aluminum hydroxide adjuvant  

Microsoft Academic Search

Langmuir adsorption isotherms of endotoxin and aluminum-containing adjuvants at pH 7.4 and 25°C revealed that aluminum hydroxide adjuvant has a greater adsorption capacity (283 ?g\\/mg Al) and adsorption coefficient (1.3×104 ml\\/?g) than aluminum phosphate adjuvant (3.0 ?g\\/mg Al, 0.20 ml\\/?g). The difference in endotoxin adsorption was related to two adsorption mechanisms: electrostatic attraction and covalent bonding. The isoelectric point (iep)

Yi Shi; Harm HogenEsch; Fred E. Regnier; Stanley L. Hem



Endotoxin antibodies in African sleeping sickness.  


Antibodies to the core region of endotoxin (endotoxin core antibodies, EndoCAb), which cross-react with endotoxin from a range of Gram-negative bacteria, are maintained in relative homeostasis in health, but undergo marked changes in a number of different diseases associated directly or indirectly with endotoxaemic or septicaemic states. The levels of EndoCAb IgG in the blood and cerebrospinal fluid (CSF) of 35 late-stage sleeping sickness patients and 9 control individuals were measured by ELISA. EndoCAb levels were significantly elevated in the patient blood (mean EndoCAb value 290 MU/ml cf. control 182 MU/ml, P < 0.001), and CSF (mean EndoCAb value 254 MU/ml cf. control 150 MU/ml, P < 0.001). EndoCAb IgG levels correlated with endotoxin levels in patient blood (r = 0.78, P < 0.001), but not in the CSF and were not reduced 6 weeks following chemotherapy, unlike the endotoxin levels. It is concluded that late-stage sleeping sickness is associated with chronic exposure to endotoxins from Gram-negative bacteria. PMID:9107022

Pentreath, V W; Alafiatayo, R A; Barclay, G R; Crawley, B; Doua, F; Oppenheim, B A



Chronic biliary obstruction induces pulmonary intravascular phagocytosis and endotoxin sensitivity in rats.  

PubMed Central

Endotoxin sensitivity varies among animal species and appears to correlate with the presence of pulmonary intravascular macrophage (PIM). In rats, which lack PIM, we investigated the hypothesis that chronic cholestatic liver injury leads to induction of PIM and endotoxin sensitivity. Rats were randomized to either common bile duct ligation (BDL) or sham-surgery and studied at 1 wk (acute cholestasis), 2 wk (cholestasis, early cirrhosis), and 4 wk (cholestasis, established cirrhosis) after surgery. Intravascularly injected fluorescent latex microspheres (1 micron diameter) were taken up by large phagocytic cells in lung parenchyma of BDL rats (at 2 and 4 wk), while no uptake was observed in lungs from control rats. Electronmicroscopy revealed accumulation of large, mononuclear, macrophage-like cells containing ingested latex particles within the pulmonary capillaries. Pulmonary intravascular phagocytosis, as reflected in lung uptake of 99mTc microaggregated albumin (Microlite, mean particle diameter = 1 micron), averaged 0.7 +/- 0.1% (mean +/- SEM) of total injected dose in 13 control rats and progressively increased with time after BDL (1 wk, 1.7 +/- 0.2%; 2 wk, 10.0 +/- 3.0%; 4 wk 35.1 +/- 5.9%). Rats with biliary cirrhosis were markedly sensitive to the lethal effects of low dose endotoxin and demonstrated marked lung edema at the time of death. Furthermore, the lung uptake of intravascular 125I-lipopolysaccharide was increased five-fold in cirrhotic rats. We conclude that chronic biliary obstruction leads to the induction of pulmonary intravascular phagocytes and enhances endotoxin sensitivity in rats. Pulmonary intravascular phagocytosis in patients with advanced cirrhosis may account for their increased susceptibility to sepsis-induced adult respiratory distress syndrome. Images PMID:7962547

Chang, S W; Ohara, N



A true theranostic approach to medicine: Towards tandem sensor detection and removal of endotoxin in blood.  


Sepsis is one of the leading causes of death around the world. The condition occurs when a local infection overcomes the host natural defense mechanism and suddenly spreads into the circulatory system, triggering a vigorous, self-injurious inflammatory host response. The pathogenesis of sepsis is relatively well known, one of the most potent immuno-activator being bacterial lipopolysaccharide (LPS) - also known as 'endotoxin'. Tests exist to detect endotoxin in bodily fluids, but are expensive, not necessarily user-friendly and require reporter molecules. In addition, the situation for safe and effective anti-endotoxin therapy is problematical. At the present time, endotoxin removal through cartridge hemoperfusion is one of the better alternatives to combat sepsis. The capability to both measure endotoxemia levels and offer an adapted response treatment in a timely manner is crucial for better management and improved prognosis, but is currently unavailable. In this context, we describe herein preliminary research towards the development of an alternative LPS biosensor and an innovative LPS neutralization cartridge to be eventually combined in an all-integrated configuration for the theranostic, personalized treatment of blood endotoxemia/sepsis. LPS detection is performed in a real-time and label-free manner in full human blood plasma, using ultra-high frequency acoustic wave sensing in combination with ultrathin, oligoethylene glycol-based mixed surface chemistry imposed on piezoelectric quartz discs. Biosensing platforms are functionalized with polymyxin B (PMB), a cyclic peptide antibiotic with high affinity for LPS. Analogous surface modification is used on glass beads for the therapeutic cartridge component of the combined strategy. Incubation of LPS-spiked whole blood with PMB-bead chemistry resulted in a significant decrease in the production of pro-inflammatory TNF-? cytokine. LPS neutralization is discussed in relation to the perturbation of its supramolecular chemistry in solution. PMID:25067837

Thompson, Michael; Blaszykowski, Christophe; Sheikh, Sonia; Romaschin, Alexander



Suppressive action of resolvin D1 on the production and release of septic mediators in D-galactosamine-sensitized endotoxin shock mice  

PubMed Central

Endotoxin/septic shock is a severe condition induced during serious infections with Gram-negative bacteria. To evaluate the therapeutic potential of resolvin D1 (RvD1), a novel pro-resolving molecule, on endotoxin/septic shock, we investigated the effect of RvD1 on the extracellular release of high mobility group box-1 (HMGB1), the production of inflammatory cytokines, the accumulation of peritoneal cells and hepatocyte apoptosis in vivo using a D-galactosamine (GalN)-sensitized mouse endotoxin shock model. Serum HMGB1 levels were markedly elevated after challenge with lipopolysaccharide (LPS)/D-GalN, and RvD1 administration significantly reduced HMGB1 levels. Furthermore, the serum levels of inflammatory cytokines, such as TNF-?, IL-6, IL-10 and macrophage chemotactic protein (MCP)-1 were elevated in the endotoxin shock model. Importantly, RvD1 administration slightly reduced the TNF-?, IL-6 and IL-10 levels, and further lowered MCP-1 levels. Moreover, RvD1 administration affected the peritoneal cell accumulation and decreased the neutrophil population. Finally, LPS/D-GalN injection induced apoptosis in the liver (mostly of hepatocytes), and RvD1 administration reduced the apoptosis of hepatocytes. These observations suggest that RvD1 may be a therapeutic agent for sepsis/endotoxin shock by exerting suppressive action on the release and production of septic mediators (HMGB1 and inflammatory cytokines), the accumulation of peritoneal cells and hepatic apoptosis. PMID:22977469




Inhibiting TNF-? signaling does not attenuate induction of endotoxin tolerance  

PubMed Central

Tumor necrosis factor-alpha (TNF-?) is a central mediator of inflammatory responses elicited by Toll-like receptor agonists, such as the Gram-negative bacterial outer membrane antigen lipopolysaccharide (LPS). TNF-? is responsible for altering vascular permeability and activating infiltrating inflammatory cells, such as monocytes and neutrophils. Interestingly, TNF-? has also demonstrated the ability to induce tolerance to subsequent challenges with TNF-? or LPS in monocyte and macrophage cell populations. Tolerance is characterized by the inability to mount a typical inflammatory response during subsequent challenges following the initial exposure to an inflammatory mediator such as LPS. The ability of TNF-? to induce a tolerant-like state with regard to LPS is most likely a regulatory mechanism to prevent excessive inflammation. We hypothesized that the induction of tolerance or the degree of tolerance is dependent upon the production of TNF-? during the primary response to LPS. To investigate TNF-?-dependent tolerance, human monocytic THP-1 cells were treated with TNF-?-neutralizing antibodies or antagonistic TNF-? receptor antibodies before primary LPS stimulation and then monitored for the production of TNF-? during the primary and challenge stimulation. During the primary stimulation, anti-TNF-? treatment effectively attenuated the production of TNF-? and interleukin-1?; however, this reduced production did not impact the induction of endotoxin tolerance. These results demonstrate that interfering with TNF-? signaling attenuates production of inflammatory cytokines without affecting the induction of tolerance. PMID:25506235

Loosbroock, Christopher; Hunter, Kenneth W



Determination of endotoxin through an aptamer-based impedance biosensor.  


Lipopolysaccharide (LPS) often referred to endotoxin is an undesirable impurity frequently entrained with various recombinant protein therapeutics and plasmid DNA (pDNA) vaccines of bacterial origin. The inherent toxicities (e.g. fever, hypotension, shock and death) of LPS render its early and sensitive detection essential for several biological assays and/or parenteral administrations of biotherapeutics. In this study, an electrochemical biosensor using an LPS specific single stranded DNA (ssDNA) aptamer as a probe was developed. Amine-terminated aptamer exhibiting high affinity (K(d)=11.9 nM) to LPS was immobilized on a gold electrode using 3-mercaptopropionic acid (MPA) as a linker. Each step of the modification process was characterized by cyclic voltammetry (CV) and electrochemical impendence spectroscopy (EIS). A good linear relationship of the changes in the charge-transfer resistance (?R(et)) and the logarithmic value of LPS concentration was demonstrated in a broad dynamic detection range of 0.001-1 ng/ml. Furthermore, the aptasensor showed a high selectivity to LPS despite the presence of pDNA, RNA and bovine serum albumin (BSA) and could be regenerated in low pH condition, offering a promising option for detecting LPS often present in a complex milieu. PMID:22182428

Su, Wenqiong; Lin, Meng; Lee, Hyuck; Cho, MiSuk; Choe, Woo-Seok; Lee, Youngkwan



A method for unobtrusive labeling of lipopolysaccharides with quantum dots.  


Bacterial endotoxins or lipopolysaccharides (LPS) are among the most potent activators of innate immune system, yet mechanisms of their action and, in particular, the role of the glycans remain elusive. Efficient noninvasive labeling strategies are necessary for studying interactions of LPS glycans with biological systems. Here, we describe a new method for labeling LPS and other lipoglycans with luminescent quantum dots (QDots). The labeling is achieved by the partitioning of hydrophobic quantum dots into the core of various LPS aggregates without disturbing the native LPS structure. The biofunctionality of the LPS-QDot conjugates is demonstrated by labeling of mouse monocytes. This simple method will find broad applicability in studies concerned with visualization of LPS biodistribution and identification of LPS-binding agents. PMID:21567322

Morales-Betanzos, Carlos; Gonzalez-Moa, Maria; Svarovsky, Sergei A



Resurrecting Inactive Antimicrobial Peptides from the Lipopolysaccharide Trap  

PubMed Central

Host defense antimicrobial peptides (AMPs) are a promising source of antibiotics for the treatment of multiple-drug-resistant pathogens. Lipopolysaccharide (LPS), the major component of the outer leaflet of the outer membrane of Gram-negative bacteria, functions as a permeability barrier against a variety of molecules, including AMPs. Further, LPS or endotoxin is the causative agent of sepsis killing 100,000 people per year in the United States alone. LPS can restrict the activity of AMPs inducing aggregations at the outer membrane, as observed for frog AMPs, temporins, and also in model AMPs. Aggregated AMPs, “trapped” by the outer membrane, are unable to traverse the cell wall, causing their inactivation. In this work, we show that these inactive AMPs can overcome LPS-induced aggregations while conjugated with a short LPS binding ?-boomerang peptide motif and become highly bactericidal. The generated hybrid peptides exhibit activity against Gram-negative and Gram-positive bacteria in high-salt conditions and detoxify endotoxin. Structural and biophysical studies establish the mechanism of action of these peptides in LPS outer membrane. Most importantly, this study provides a new concept for the development of a potent broad-spectrum antibiotic with efficient outer membrane disruption as the mode of action. PMID:24419338

Mohanram, Harini



First evidence for a covalent linkage between enterobacterial common antigen and lipopolysaccharide in Shigella sonnei phase II ECALPS.  


Enterobacterial common antigen (ECA) is expressed by Gram-negative bacteria belonging to Enterobacteriaceae, including emerging drug-resistant pathogens such as Escherichia coli, Klebsiella pneumoniae, and Proteus spp. Recent studies have indicated the importance of ECA for cell envelope integrity, flagellum expression, and resistance of enteric bacteria to acetic acid and bile salts. ECA, a heteropolysaccharide built from the trisaccharide repeating unit, ?3)-?-D-Fucp4NAc-(1?4)-?-D-ManpNAcA-(1?4)-?-D-GlcpNAc-(1?, occurs as a cyclic form (ECA(CYC)), a phosphatidylglycerol (PG)-linked form (ECA(PG)), and an endotoxin/lipopolysaccharide (LPS)-associated form (ECA(LPS)). Since the discovery of ECA in 1962, the structures of ECA(PG) and ECA(CYC) have been completely elucidated. However, no direct evidence has been presented to support a covalent linkage between ECA and LPS; only serological indications of co-association have been reported. This is paradoxical, given that ECA was first identified based on the capacity of immunogenic ECA(LPS) to elicit antibodies cross-reactive with enterobacteria. Using a simple isolation protocol supported by serological tracking of ECA epitopes and NMR spectroscopy and mass spectrometry, we have succeeded in the first detection, isolation, and complete structural analysis of poly- and oligosaccharides of Shigella sonnei phase II ECA(LPS). ECA(LPS) consists of the core oligosaccharide substituted with one to four repeating units of ECA at the position occupied by the O-antigen in the case of smooth S. sonnei phase I. These data represent the first structural evidence for the existence of ECA(LPS) in the half-century since it was first discovered and provide insights that could prove helpful in further structural analyses and screening of ECA(LPS) among Enterobacteriaceae species. PMID:24324266

Gozdziewicz, Tomasz K; Lugowski, Czeslaw; Lukasiewicz, Jolanta



Human endothelial cell-based assay for endotoxin as sensitive as the conventional Limulus Amebocyte Lysate assay.  


Endotoxin, also known as lipopolysaccharide (LPS) produced by bacteria can be present in any liquid or on any biomaterial even if the material is sterile. Endotoxin in mammals can cause fever, inflammation, cell and tissue damage and irreversible septic shock and death. In the body, endothelial cells making up the blood vasculature and endothelial cells in vitro rapidly react to minute amounts of endotoxin resulting in a rapid induction of the cell adhesion molecule E-selectin. In this study we have used immunofluorescent staining to evaluate the expression of E-selectin on human microvascular endothelial cells from the skin (HDMEC) and human umbilical vein endothelial cells (HUVEC) exposed to various concentrations of LPS. In addition, the sensitivity of detection was compared with the most widely used assay for the presence of endotoxin, the Limulus Amebocyte Lysate assay (LAL). The detection of E-selectin on endothelial cells in the presence of LPS for 4 h was found to be at least as sensitive in detecting the same concentration using the LAL assay. A cell adhesion molecule-enzyme immunosorbent assay was also developed and used to quantify LPS using the endothelial cell model. A comparison of LAL and the immunofluorescent staining method was carried out with solutions, nanoparticles, biomaterial extracts and endothelial cells grown directly on biomaterials. Under all conditions, the endothelial/E-selectin model system was positive for the test samples that were positive by LAL. Thus, we propose the use of this highly sensitive, rapid, reproducible assay for the routine testing of endotoxin in all steps in the manufacturing process of materials destined for use in humans. This can give a rapid feedback and localization of bacterial contamination sources with the LAL being reserved for the testing of the final product. PMID:24456607

Unger, Ronald E; Peters, Kirsten; Sartoris, Anne; Freese, Christian; Kirkpatrick, C James



Concentrations of bovine lactoferrin and citrate in milk during experimental endotoxin mastitis in early- versus late-lactating dairy cows.  


Lactoferrin (Lf) is a molecule naturally present in bovine milk that affects the availability and transport systems of iron. Lf also binds endotoxin (lipopolysaccharide, LPS) of Gram-negative bacteria and modulates the immunological response. In the present study, concentrations of bovine Lf (bLf) and citrate in milk were determined in early (EL) and late (LL) lactating dairy cows, using an experimentally induced endotoxin mastitis model and a crossover design. Nine clinically healthy Finnish Ayrshire cows were challenged twice with 100 ?g endotoxin infused into one udder quarter. Milk samples were collected from the challenged and control quarters of each cow before and after endotoxin infusion during 3 d, and bLf and citrate concentrations were measured. In all cows, clinical signs of mastitis were seen at both times of challenge, but the response was more severe in EL than in LL. Concentration of bLf in the milk started to rise approximately 8 h after endotoxin infusion and was still higher than normal on the third day, especially in the late-lactating cows. In milk of the LL group, concentrations of bLf were significantly higher than in the EL group. In contrast, concentrations of citrate were higher in milk of the EL cows compared with the LL cows. Concentration of bLf and citrate varied substantially among cows. The molar ratio of citrate to bLf before and after challenge was significantly higher during the EL period. The results of this study partly explain why cows in early lactation are more susceptible to intramammary infections and why mastitis is more severe in them. PMID:20800005

Hyvönen, Paula; Haarahiltunen, Taina; Lehtolainen, Tanja; Heikkinen, Jouni; Isomäki, Ritva; Pyörälä, Satu



Endotoxins and inflammation in hemodialysis patients.  


Long-term endotoxin challenge may promote frequent complications in dialysis patients, namely malnutrition, chronic inflammation, and atherosclerosis, which are recognized as the so-called MIA syndrome. Circulating soluble vascular cell adhesion molecule-1 (sVCAM-1) levels may be used to determine the stage of atherosclerosis. This study aimed to assess endotoxin level in hemodialysis (HD) patients and its role in inducing inflammation. The study was conducted on 50 HD patients, chosen from four dialysis centers in Alexandria. Serum blood samples were collected for the determination of albumin and C-reactive protein (CRP), and whole blood samples were used for the measurement of hemoglobin level. A heparinized whole blood sample was taken postdialysis for endotoxin assay by limulus amebocyte lysate test, and in addition to sVCAM-1 was estimated using enzyme-linked immunosorbent assay. The mean endotoxin level was 76.30?pg/mL;80% exhibited values higher than 60?pg/mL. Half the studied patients had CRP values that exceeded the upper limit of the laboratory reference range (<6.0?mg/L). A statistically significant correlation was found between endotoxin and CRP levels (r?=?0.47, P?=?0.001). The mean pre-HD level of VCAM was 1851.00?ng/mL, while the mean post-HD level was 2829.00?ng/mL with statistically significant correlation (r?=?0.354, P?=?0.012) and it also correlated significantly with endotoxin as well as CRP levels. Endotoxemia may play an important role in the aggravation of endothelial dysfunction in HD patients as indicated by the post-HD rise in sVCAM-1. PMID:23231033

El-Koraie, Ahmed F; Naga, Yasmine S; Saaran, Amina M; Farahat, Nahla G; Hazzah, Walaa A



Lipopolysaccharide triggers macrophage activation of inflammatory cytokine expression, chemotaxis, phagocytosis, and oxidative ability via a toll-like receptor 4-dependent pathway: Validated by RNA interference  

Microsoft Academic Search

RNA interference has been extensively used to knock-down the translation of certain genes. Toll-like receptor 4 (TLR4) produced by macrophages can be activated in response to endotoxin stimulation. This study used the RNA interference technique to evaluate the roles of TLR4 in lipopolysaccharide (LPS)-stimulated activation of macrophages from the aspects of cytokine production, chemotaxis, phagocytosis, and oxidative ability. Exposure of

Tsu-Tuan Wu; Ta-Liang Chen; Ruei-Ming Chen



Lipopolysaccharide: Neutralization by Polymyxin B Shuts Down the Signaling Pathway of Nuclear Factor ?B in Peripheral Blood Mononuclear Cells, Even during Activation  

Microsoft Academic Search

Background. There have been many studies on anti-lipopolysaccharide (LPS) agents and LPS-neutralizing agents; however, there have been no reports on the changes in clinical status and mediators that occur when these agents are used. Polymyxin (PMX) (treatment using a column containing polymyxin B-immobilized fiber) removed circulating endotoxin, and reduced various cytokines within 120 min, even in patients with high levels

Hideyuki Tsuzuki; Tohru Tani; Hisao Ueyama; Masashi Kodama



Central involvement of kinin B1 and B2 receptors in the febrile response induced by endotoxin in rats  

PubMed Central

The effect of central injection of selective kinin B1 and B2 receptor antagonists on the febrile response induced by endotoxin (E. coli lipopolysaccharide, LPS) in rats was investigated. Intracerebroventricular (i.c.v.) injection of a selective B2 receptor antagonist (Hoe-140, 8?nmol) reduced the early (0–2?h), but increased the late phase (4–6?h) of the febrile response induced by intravenous (i.v.) injection of LPS (0.5??g?kg?1). Co-administration of Hoe-140 (8?nmol, i.c.v.) with LPS (0.5??g?kg?1, i.v.), followed 2.5?h later by the i.c.v. injection of a selective B1 receptor antagonist [des-Arg9-Leu8]-bradykinin (BK, 8?nmol), significantly reduced the febrile response induced by LPS throughout the whole experimental period. Intravenous injection of Hoe-140 (1?mg?kg?1) significantly reduced the febrile response induced by LPS (0.5??g?kg?1, i.p.). Pretreatment (24?h) with LPS (0.5??g?kg?1, i.v.) reduced the febrile response induced by BK or [Tyr8]-BK (both, 5?nmol, i.c.v.), but markedly increased the febrile response induced by [des-Arg9]-BK (5?nmol, i.c.v.). The response induced by [des-Arg9]-BK in LPS-pretreated rats was significantly inhibited by co-injection of [des-Arg9-Leu8]-BK (15?nmol, i.c.v.). The results suggest that kinins are involved in the induction of LPS-induced fever and that central B2 and B1 receptors are activated during the initial and late phase of this response, respectively. The results also suggest that downregulation and/or desensitization of B2 receptors and induction and/or upregulation of B1 receptors in LPS-pretreated animals may have a significant pathophysiologcal role in the induction and maintenance of fever. These observations may be specifically important in the case of chronic inflammatory conditions, because the BK metabolite [des-Arg9]-BK, so far considered an inactive metabolite, acquires an active and relevant role with the progressive expression of B1 receptors that occurs in such states. PMID:9154340

Coelho, M M; Oliveira, C R; Pajolla, G P; Calixto, J B; Pelá, I R



Sirt1 Deletion Leads to Enhanced Inflammation and Aggravates Endotoxin-Induced Acute Kidney Injury  

PubMed Central

Bacterial endotoxin has been known to induce excessive inflammatory responses and acute kidney injury. In the present study, we used a mouse model of endotoxemia to investigate the role of Sirt1 in inflammatory kidney injury. We examined molecular and cellular responses in inducible Sirt1 knockout (Sirt1?/?) mice and wild type littermates (Sirt1+/+) in lipopolysaccharide (LPS)-induced kidney injury. Our studies demonstrated that Sirt1 deletion caused aggravated kidney injury, which was associated with increased inflammatory responses including elevated pro-inflammatory cytokine production, and increased ICAM-1 and VCAM-1 expression. Inflammatory signaling such as STAT3/ERK phosphorylation and NF-?B activation was markedly elevated in kidney tissues of Sirt1 knockout mice after LPS challenge. The results indicate that Sirt1 is protective against LPS-induced acute kidney injury by suppressing kidney inflammation and down-regulating inflammatory signaling. PMID:24896770

Gao, Rong; Chen, Jiao; Hu, Yuxin; Li, Zhenyu; Wang, Shuxia; Shetty, Sreerama; Fu, Jian



Endotoxins in Environmental and Clinical Samples Assessed by GC-Tandem MS  

NASA Astrophysics Data System (ADS)

Bacteria appeared on the Earth millions years before us and human evolution was triggered by the constant presence of pathogenic and symbiotic microorganisms in our surroundings. Interplay occurred between higher organism and microbial consortia residing in the host organs and on the epithelial surfaces; another natural space of bacteria-human interaction is the indoor environment where we spend the majority of our lifetime. Indoor microbial exposure affects our well-being and can result in respiratory symptoms, such as allergies and asthma, since both dead and live microorganisms and their cell constituents, including lipopolysaccharides (LPS, endotoxins), interact with our immune system. Thus, there is a demand for robust tools for qualitative and quantitative determination of the microbial communities that we are exposed to.

Szponar, Bogumila


Removal of endotoxin from dairy wastewater  

Technology Transfer Automated Retrieval System (TEKTRAN)

The efficacy of various treatments on removing endotoxin (ET) from wastewater was tested by using the treated water to induce a systemic reaction via intratracheal inoculation (20 ml/goat, 6 goats/group). Treatments (T1-T7) of wastewater were as follows: 1) autoclaved 15 min, centrifuged and contain...


[The role of cytokines in endotoxic shock and in endotoxin hypersensitivity].  


Endotoxins (lipopolysaccharides, LPS) are constituents of the outer membrane of gram-negative bacteria. The application of purified LPS to experimental animals leads to the development of many pathophysiological activities which are also seen during infection with gram-negative microorganisms. One important prerequisite for the development of endotoxin shock is the interaction of LPS with macrophages, the activation of which leads to the release of cytokines, in particular of TNF alpha and IL-1, which mediate the toxic activity of LPS. The interaction of LPS with target cells and the subsequent initiation of endotoxin shock may be modified by plasma proteins that are capable of binding LPS. The most important LPS-binding proteins known so far are high density lipoprotein (HDL), low density lipoprotein (LDL), LPS-binding protein (LBP) and specific LPS antibodies. Native LPS released from bacteria may be associated partly with bacterial proteins (e.g. OmpA) which may also modify its interaction with host targets. The sensitivity of the organism to LPS is genetically determined, but may be altered under different experimental conditions. Hypersensitivity to LPS may be achieved by treatment with live (infection) or killed microorganisms, growing tumors, hepatotoxic agents or treatment with proteins to which the organism has been immunologically primed. The state of hypersensitivity is characterized by an increased ability of hypersensitive animals to produce cytokines on LPS challenge, as well as by an increased susceptibility to the toxic activity of TNF alpha. Recently it could be shown that interferon gamma (IFN gamma) is a central mediator in the development of the hypersensitivity to LPS induced by infection. PMID:8340136

Freudenberg, M A; Ness, T; Kumazawa, Y; Galanos, C



Detection of antibody specificity of raw bovine and human milk to bacterial lipopolysaccharides using PCFIA  

Microsoft Academic Search

Raw milk from non?immunized cows and raw human milk from lactating mothers were examined for specificity and antibody activity against lipopolysaccharides (LPS) of five pathogenic bacteria, i.e. Escherichia coli O111:B4, E. coli O128:B12, Salmonella enteritidis, S. typhimurium and Shigella flexneri 1A in a particle concentration fluorescence immunoassay (PCFIA). Bacterial LPS was covalently coated on submicron polystyrene particles and used in

Jack N. Losso; Jyoti Dhar; Angela Kummer; Shuryo Nakai



Proteins and endotoxin in house dust mite extracts modulate cytokine secretion and gene expression by dermal fibroblasts  

PubMed Central

House dust mite extracts used for diagnostic tests and immunotherapy contain bioreactive molecules including proteins and endotoxin. These extracts can influence the cytokine secretion and adhesion molecule expression by cells in the skin and lung airways. The aim of this study was to determine the role of proteins and endotoxin in mite extracts in modulating gene expression and cytokine secretion by human dermal fibroblasts. Cultured normal human dermal fibroblasts were stimulated with whole mite extracts, mite extracts boiled to denature proteins, or mite extracts treated with polymyxin B to inactivate lipopolysaccharide. Gene expression and secretion of interleukin-6 (IL-6), IL-8, and monocyte chemoattractant protein-1 (MCP-1) were determined after 6 h of stimulation. Whole Dermatophagoides farinae, D. pteronyssinus and Euroglyphus maynei extracts induced dose-dependent IL-6 and IL-8 secretion. In addition, D. farinae and E. maynei induced secretion of MCP-1. D. farinae and E. maynei also induced parallel cytokine gene expression. Cells stimulated with boiled D. farinae extract showed moderate to marked reductions in IL-6 and IL-8 secretion. In contrast, boiled D. pteronyssinus and E. maynei extracts induced equal or greater cytokine secretions than untreated extracts. The stimulating properties were reduced for all three extracts following treatment with polymyxin B. Our data suggest that both endotoxin and proteins in mite extracts modulate the secretion of cytokines by dermal fibroblasts. The biological activities of D. farinae, D. pteronyssinus, and E. maynei extracts are not equivalent. There appears to be a lipopolysaccharide-binding protein in some mite extracts. PMID:23640713

Rockwood, Jananie; Morgan, Marjorie S.; Arlian, Larry G.



Proteins and endotoxin in house dust mite extracts modulate cytokine secretion and gene expression by dermal fibroblasts.  


House dust mite extracts used for diagnostic tests and immunotherapy contain bioreactive molecules including proteins and endotoxin. These extracts can influence the cytokine secretion and adhesion molecule expression by cells in the skin and lung airways. The aim of this study was to determine the role of proteins and endotoxin in mite extracts in modulating gene expression and cytokine secretion by human dermal fibroblasts. Cultured normal human dermal fibroblasts were stimulated with whole mite extracts, mite extracts boiled to denature proteins, or mite extracts treated with polymyxin B to inactivate lipopolysaccharide. Gene expression and secretion of interleukin-6 (IL-6), IL-8, and monocyte chemoattractant protein-1 (MCP-1) were determined after 6 h of stimulation. Whole Dermatophagoides farinae, D. pteronyssinus and Euroglyphus maynei extracts induced dose-dependent IL-6 and IL-8 secretion. In addition, D. farinae and E. maynei induced secretion of MCP-1. Dermatophagoides farinae and E. maynei also induced parallel cytokine gene expression. Cells stimulated with boiled D. farinae extract showed moderate to marked reductions in IL-6 and IL-8 secretion. In contrast, boiled D. pteronyssinus and E. maynei extracts induced equal or greater cytokine secretions than untreated extracts. The stimulating properties were reduced for all three extracts following treatment with polymyxin B. Our data suggest that both endotoxin and proteins in mite extracts modulate the secretion of cytokines by dermal fibroblasts. The biological activities of D. farinae, D. pteronyssinus, and E. maynei extracts are not equivalent. There appears to be a lipopolysaccharide-binding protein in some mite extracts. PMID:23640713

Rockwood, Jananie; Morgan, Marjorie S; Arlian, Larry G



Diet-induced obesity attenuates endotoxin-induced cognitive deficits.  


Activation of the immune system can impair cognitive function, particularly on hippocampus dependent tasks. Several factors such as normal aging and prenatal experiences can modify the severity of these cognitive deficits. One additional factor that may modulate the behavioral response to immune activation is obesity. Prior work has shown that obesity alters the activity of the immune system. Whether diet-induced obesity (DIO) influences the cognitive deficits associated with inflammation is currently unknown. The present study explored whether DIO alters the behavioral response to the bacterial endotoxin, lipopolysaccharide (LPS). Female C57BL/6J mice were fed a high-fat (60% fat) or control diet (10% fat) for a total of five months. After consuming their respective diets for four months, mice received an LPS or saline injection and were assessed for alterations in spatial learning. One month later, mice received a second injection of LPS or saline and tissue samples were collected to assess the inflammatory response within the periphery and central nervous system. Results showed that LPS administration impaired spatial learning in the control diet mice, but had no effect in DIO mice. This lack of a cognitive deficit in the DIO female mice is likely due to a blunted inflammatory response within the brain. While cytokine production within the periphery (i.e., plasma, adipose, and spleen) was similar between the DIO and control mice, the DIO mice failed to show an increase in IL-6 and CD74 in the brain following LPS administration. Collectively, these data indicate that DIO can reduce aspects of the neuroinflammatory response as well as blunt the behavioral reaction to an immune challenge. PMID:25542778

Setti, Sharay E; Littlefield, Alyssa M; Johnson, Samantha W; Kohman, Rachel A



Endotoxin-Induced Changes in Phospholipid Dynamics of the Stomach  

PubMed Central

Background The gastric mucosa is protected in part by a hydrophobic layer of phosphatidylcholine (PC) that overlies the mucus gel on the stomach. Endotoxin treatment (i.e., lipopolysaccharide or LPS) results in an apparent disruption of this layer as evidenced by a reduction in surface hydrophobicity and an increase in transmural permeability. The current studies compared PC and lyso-PC levels in mucus and gastric mucosa before and after LPS treatment, and examined potential mechanisms for surface phospholipid changes. Methods Rats were administered LPS (5 mg//kg, ip) and samples were collected after 5 h for analysis of PC and its primary degradant, lyso-PC, in the loosely and firmly adherent mucus layers, and the mucosa. The dependence of LPS-induced effects on gastric alkalinization, PC synthetic activity, and intestinal reflux material was assessed. Results The gastric contents after LPS, which also contained duodenal reflux material, had greatly increased amounts of PC and lyso-PC. The firmly adherent mucus layer was unchanged. The gastric mucosa after LPS revealed significant reductions of PC levels and no change in lyso-PC content. These phospholipid changes were not caused by alkalinization of the stomach or altered PC synthesis. Prevention of duodenogastric reflux by pylorus ligation blocked the LPS-induced increase in luminal lyso-PC and the reduction in mucosal PC. Conclusions LPS appears to induce a release of PC from gastric mucosa into the lumen, along with degradation of PC to lyso-PC, without an affect on PC synthesis. Component(s) of intestinal reflux material appear to be required for these effects. The lowered PC levels in gastric mucosa after LPS may contribute to reduced barrier properties of this tissue. PMID:23158407

Dial, Elizabeth J.; Tran, Duy M.; Hyman, Ari; Lichtenberger, Lenard M.



Involvement of platelet-activating factor (PAF) in endotoxin-induced intestinal motor disturbances in rats.  


Intestinal myoelectrical activity was investigated in conscious fasted rats chronically implanted with Nichrome electrodes in the duodeno-jejunum. Motility of the small intestine was characterized by the presence of migrating myoelectric complex (MMC) occurring regularly at 16.2 +/- 5.8 minute intervals. Intravenous administration of endotoxin (E. coli S.0111:B4) at a dose of 50 micrograms/kg increased the interval between MMC to 112.6 +/- 26.8 min, the duration of these effects being dose-related between 10 to 100 micrograms/kg. Such a typical myoelectrical alteration, corresponding to rapidly propagated groups of spike bursts, was mimicked by the IP administration of PAF at doses of 10 to 50 micrograms/kg. Previous administration of BN 52021, a specific PAF antagonist at a dose of 50 mg/kg abolished the motor alterations induced by IP injection of PAF (25 micrograms/kg) and significantly (p less than 0.01) reduced by 61.2% those induced by IV endotoxin (50 micrograms/kg). Indomethacin (10 mg/kg IP) as well as SC 19220 (5 mg/kg IV), a PGE2 antagonist, injected prior to endotoxin (50 micrograms/kg IV) or PAF (25 micrograms/kg IP) also reduced significantly (p less than 0.01) the duration of MMC inhibition. It is concluded that endogenous release of PAF is partly responsible for the intestinal motor alterations induced by endotoxin; these effects, strongly reduced after treatment with BN 52021, are also mediated through the release of prostaglandins. PMID:2570338

Pons, L; Droy-Lefaix, M T; Braquet, P; Buéno, L



Inflammatory responses and potencies of various lipopolysaccharides from bacteria and cyanobacteria in aquatic environments and water supply systems.  


Inflammatory substances derived from indigenous bacteria in aquatic environments or water systems are of great concern. Lipopolysaccharides (LPSs), one of the major inflammatory substances in water, are usually identified using Limurus amoebocyte lysate (LAL) assay on the basis of their endotoxic activity, but endotoxin levels do not accurately represent their inflammatory potency in humans. In this investigation, the cellular endotoxin contents of pure-cultured bacteria/cyanobacteria, which are frequently detected in water sources and distribution systems, and of indigenous bacteria in a river and in biologically activated carbon (BAC) effluent, were investigated. The indigenous bacteria showed the highest endotoxin contents exceeding 10(-3)EU/cell. The LPSs were then purified from those samples, and their inflammatory potencies were examined using a human monocytic cell line. The LPSs from Acinetobacter lwoffii culture, the river water, and the BAC effluent sample revealed a unique cytokine secretion pattern; they induced both IL-8 and TNF-? more strongly than the other tested bacterial LPSs. These results suggest that natural bacterial/cyanobacterial flora in aquatic environments and water distribution systems have the potential to induce relatively strong inflammatory responses in humans; therefore, further accumulation of data on water quality from the perspective of not just endotoxins but inflammatory potency is needed. PMID:25666398

Ohkouchi, Yumiko; Tajima, Satoshi; Nomura, Masahiro; Itoh, Sadahiko



Dose Dependency and Individual Variability of the Lipopolysaccharide-Induced Bovine Acute Phase Protein Response  

Microsoft Academic Search

In order to investigate the dose dependency and the individual variability of the lipopolysaccharide (LPS)- induced acute phase protein response in cattle, 8 non- lactating, nonpregnant Danish Holstein cows were challenged 3 times each by intravenous injection of in- creasing doses (10, 100, and 1000 ng\\/kg, consecutively) of Escherichia coli LPS with 3-wk intervals. All 3 LPS doses resulted in

S. Jacobsen; P. H. Andersen; T. Toelboell; P. M. H. Heegaard



Citric acid effects on brain and liver oxidative stress in lipopolysaccharide-treated mice.  


Citric acid is a weak organic acid found in the greatest amounts in citrus fruits. This study examined the effect of citric acid on endotoxin-induced oxidative stress of the brain and liver. Mice were challenged with a single intraperitoneal dose of lipopolysaccharide (LPS; 200 ?g/kg). Citric acid was given orally at 1, 2, or 4?g/kg at time of endotoxin injection and mice were euthanized 4?h later. LPS induced oxidative stress in the brain and liver tissue, resulting in marked increase in lipid peroxidation (malondialdehyde [MDA]) and nitrite, while significantly decreasing reduced glutathione, glutathione peroxidase (GPx), and paraoxonase 1 (PON1) activity. Tumor necrosis factor-alpha (TNF-?) showed a pronounced increase in brain tissue after endotoxin injection. The administration of citric acid (1-2?g/kg) attenuated LPS-induced elevations in brain MDA, nitrite, TNF-?, GPx, and PON1 activity. In the liver, nitrite was decreased by 1?g/kg citric acid. GPx activity was increased, while PON1 activity was decreased by citric acid. The LPS-induced liver injury, DNA fragmentation, serum transaminase elevations, caspase-3, and inducible nitric oxide synthase expression were attenuated by 1-2?g/kg citric acid. DNA fragmentation, however, increased after 4?g/kg citric acid. Thus in this model of systemic inflammation, citric acid (1-2?g/kg) decreased brain lipid peroxidation and inflammation, liver damage, and DNA fragmentation. PMID:24433072

Abdel-Salam, Omar M E; Youness, Eman R; Mohammed, Nadia A; Morsy, Safaa M Youssef; Omara, Enayat A; Sleem, Amany A



Endotoxin Inhalation Alters Lung Development in Neonatal Mice  

PubMed Central

Background Childhood asthma is a significant public health problem. Epidemiologic evidence suggests an association between childhood asthma exacerbations and early life exposure to environmental endotoxin. Although the pathogenesis of endotoxin-induced adult asthma is well studied, questions remain about the impact of environmental endotoxin on pulmonary responsiveness in early life. Methods We developed a murine model of neonatal/juvenile endotoxin exposures approximating those in young children and evaluated the lungs inflammatory and remodeling responses. Results Persistent lung inflammation induced by the inhalation of endotoxin in early life was demonstrated by the influx of inflammatory cells and pro-inflammatory mediators to the airways and resulted in abnormal alveolarization. Conclusions Results of this study advance the understanding of the impact early life endotoxin inhalation has on the lower airways, and demonstrates the importance of an experimental design that approximates environmental exposures as they occur in young children. PMID:22576659

Kulhankova, Katarina; George, Caroline L.S.; Kline, Joel N.; Darling, Melissa; Thorne, Peter S.



Effects of endotoxin on monoamine metabolism in the rat.  

NASA Technical Reports Server (NTRS)

Examination of effects of administered endotoxin on catecholamine metabolism in the rat brain, sympathetic neurons, and adrenal medulla. It is found that endotoxin, administered intraperitoneally, lowers the norepinephrine content in peripheral sympathetic neurons and the brain, and the catecholamine content in the adrenal medulla. It also accelerates the disappearance of H3-norepinephrine from all these tissues. It is therefore suggested that the effects of endotoxin on body temperature may be mediated in part by central non-adrenergic neurons.

Pohorecky, L. A.; Wurtman, R. J.; Taam, D.; Fine, J.



Ultrastructural evidences of direct endotoxin action on the heart.  


In experiments on 13 rabbits, the authors performed heart perfusion according to Langendorf with endotoxin (9 experiments) or with Ringer's solution (4 experiments), and subsequently analysed the myocardial ultrastructure. They found that 30-minute endotoxin perfusion produces contracture changes, intracellular myocytolysis and desquamation of endothelial cells with destruction of the capillary basal membrane. The findings attested to myocardial dysfunction caused by direct endotoxin action on the heart. PMID:3556010

Bardakhchian, E A; Palchikova, E I



Proteinase K digestion of proteins improves detection of bacterial endotoxins by the Limulus amebocyte lysate assay: application for endotoxin removal from cationic proteins.  


Cationic proteins, such as lysozyme, ribonuclease A, and human IgG, impaired the detection of endotoxins with the Limulus amebocyte lysate assay (LAL assay) through formation of endotoxin-protein complexes, demonstrating pronounced masking of endotoxins. Methods, such as phenol extraction, dilution heating, and perchloric acid treatment failed to demask the endotoxins. Also, digestion with trypsin, chymotrypsin, or pronase recovered only 10 to 20% of the applied endotoxins. However, endotoxin recoveries up to 100% were obtained with proteinase K digestion of the samples prior to the LAL assay. This method was then applied to examine the impact of endotoxin masking on endotoxin removal from protein solutions by selective adsorption on membrane adsorbers. It was found that poly-L-lysine and poly(ethyleneimine) as endotoxin-selective ligands were able to pull endotoxins off the proteins studied, thereby guaranteeing successful decontamination. PMID:9606141

Petsch, D; Deckwer, W D; Anspach, F B



[Study on preparation and property of a new adsorbent for endotoxin removal in blood purification].  


In order to remove the endotoxin from the blood of endotoxemia patients, we prepared a new adsorbent with heparin space arm and polymyxin B (PMB) ligand. The carrier of chloromethyl polystyrene resin was activated and heparin space arm was grafted, and then PMB ligand was immobilized onto adsorbent with glutaraldehyde. We employed in vitro FITC-lipopolysaccharide (FITC-LPS) static adsorption to characterize the adsorption properties on the adsorbent, and conducted in vitro lipopolysaccharide (LPS) static adsorption to measure quantitavely the adsorption capacity and rate, and then evaluated the blood compatibility. The in vitro static adsorption indicated that the adsorbent had the removal rate of LPS above 70% with the adsorption equilibrium time for 2 hours. Blood compatibility experiment showed that the adsorbent had little negative effects on blood cells and plasma protein, and their adsorption rates were less than 10% for hemocytes and 20% for plasma protein respectively. This adsorbent exhibited high selectivity, high adsorption capacity and good biocompatibility, and presented a promising clinical application in the treatment of endotoxemia. PMID:23865333

Wang, Feifei; Wang, Xiang; Xiong, Yanlian; Xu, Pei; Jin, Xinxin; Tang, Jinlong; Mao, Jinchun



The Origin of 8-Amino-3,8-dideoxy-d-manno-octulosonic Acid (Kdo8N) in the Lipopolysaccharide of Shewanella oneidensis*  

PubMed Central

Lipopolysaccharide (LPS; endotoxin) is an essential component of the outer monolayer of nearly all Gram-negative bacteria. LPS is composed of a hydrophobic anchor, known as lipid A, an inner core oligosaccharide, and a repeating O-antigen polysaccharide. In nearly all species, the first sugar bridging the hydrophobic lipid A and the polysaccharide domain is 3-deoxy-d-manno-octulosonic acid (Kdo), and thus it is critically important for LPS biosynthesis. Modifications to lipid A have been shown to be important for resistance to antimicrobial peptides as well as modulating recognition by the mammalian innate immune system. Therefore, lipid A derivatives have been used for development of vaccine strains and vaccine adjuvants. One derivative that has yet to be studied is 8-amino-3,8-dideoxy-d-manno-octulosonic acid (Kdo8N), which is found exclusively in marine bacteria of the genus Shewanella. Using bioinformatics, a candidate gene cluster for Kdo8N biosynthesis was identified in Shewanella oneidensis. Expression of these genes recombinantly in Escherichia coli resulted in lipid A containing Kdo8N, and in vitro assays confirmed their proposed enzymatic function. Both the in vivo and in vitro data were consistent with direct conversion of Kdo to Kdo8N prior to its incorporation into the Kdo8N-lipid A domain of LPS by a metal-dependent oxidase followed by a glutamate-dependent aminotransferase. To our knowledge, this oxidase is the first enzyme shown to oxidize an alcohol using a metal and molecular oxygen, not NAD(P)+. Creation of an S. oneidensis in-frame deletion strain showed increased sensitivity to the cationic antimicrobial peptide polymyxin as well as bile salts, suggesting a role in outer membrane integrity. PMID:23413030

Gattis, Samuel G.; Chung, Hak Suk; Trent, M. Stephen; Raetz, Christian R. H.



Milk Thistle Extract and Silymarin Inhibit Lipopolysaccharide Induced Lamellar Separation of Hoof Explants in Vitro  

PubMed Central

The pathogenesis of laminitis is not completely identified and the role of endotoxins (lipopolysaccharides, LPS) in this process remains unclear. Phytogenic substances, like milk thistle (MT) and silymarin, are known for their anti-inflammatory and antioxidant properties and might therefore have the potential to counteract endotoxin induced effects on the hoof lamellar tissue. The aim of our study was to investigate the influence of endotoxins on lamellar tissue integrity and to test if MT and silymarin are capable of inhibiting LPS-induced effects in an in vitro/ex vivo model. In preliminary tests, LPS neutralization efficiency of these phytogenics was determined in an in vitro neutralization assay. Furthermore, tissue explants gained from hooves of slaughter horses were tested for lamellar separation after incubation with different concentrations of LPS. By combined incubation of explants with LPS and either Polymyxin B (PMB; positive control), MT or silymarin, the influence of these substances on LPS-induced effects was assessed. In the in vitro neutralization assay, MT and silymarin reduced LPS concentrations by 64% and 75%, respectively, in comparison PMB reduced 98% of the LPS concentration. In hoof explants, LPS led to a concentration dependent separation. Accordantly, separation force was significantly decreased by 10 µg/mL LPS. PMB, MT and silymarin could significantly improve tissue integrity of explants incubated with 10 µg/mL LPS. This study showed that LPS had a negative influence on the structure of hoof explants in vitro. MT and silymarin reduced endotoxin activity and inhibited LPS-induced effects on the lamellar tissue. Hence, MT and silymarin might be used to support the prevention of laminitis and should be further evaluated for this application. PMID:25290524

Reisinger, Nicole; Schaumberger, Simone; Nagl, Veronika; Hessenberger, Sabine; Schatzmayr, Gerd



Milk thistle extract and silymarin inhibit lipopolysaccharide induced lamellar separation of hoof explants in vitro.  


The pathogenesis of laminitis is not completely identified and the role of endotoxins (lipopolysaccharides, LPS) in this process remains unclear. Phytogenic substances, like milk thistle (MT) and silymarin, are known for their anti-inflammatory and antioxidant properties and might therefore have the potential to counteract endotoxin induced effects on the hoof lamellar tissue. The aim of our study was to investigate the influence of endotoxins on lamellar tissue integrity and to test if MT and silymarin are capable of inhibiting LPS-induced effects in an in vitro/ex vivo model. In preliminary tests, LPS neutralization efficiency of these phytogenics was determined in an in vitro neutralization assay. Furthermore, tissue explants gained from hooves of slaughter horses were tested for lamellar separation after incubation with different concentrations of LPS. By combined incubation of explants with LPS and either Polymyxin B (PMB; positive control), MT or silymarin, the influence of these substances on LPS-induced effects was assessed. In the in vitro neutralization assay, MT and silymarin reduced LPS concentrations by 64% and 75%, respectively, in comparison PMB reduced 98% of the LPS concentration. In hoof explants, LPS led to a concentration dependent separation. Accordantly, separation force was significantly decreased by 10 µg/mL LPS. PMB, MT and silymarin could significantly improve tissue integrity of explants incubated with 10 µg/mL LPS. This study showed that LPS had a negative influence on the structure of hoof explants in vitro. MT and silymarin reduced endotoxin activity and inhibited LPS-induced effects on the lamellar tissue. Hence, MT and silymarin might be used to support the prevention of laminitis and should be further evaluated for this application. PMID:25290524

Reisinger, Nicole; Schaumberger, Simone; Nagl, Veronika; Hessenberger, Sabine; Schatzmayr, Gerd



In vitro toxicity and interactions of environmental contaminants (Arochlor 1254 and mercury) and immunomodulatory agents (lipopolysaccharide and cortisol) on thymocytes from lake trout (Salvelinus namaycush)  

USGS Publications Warehouse

The immunotoxicity of chemical combinations commonly encountered by the lake trout (Salvelinus namaycush) immune system was the focus of this study. It was hypothesised that combinations of an environmental contaminant (mercuric chloride or Aroclor 1254) and an immunomodulatory agent (bacterial endotoxin or cortisol) might interact to produce a greater toxicity than that of the environmental contaminant alone at concentrations typically encountered in piscine blood and other tissues. Thus lake trout thymocytes were isolated and treated with mercuric chloride or Aroclor 1254 in the presence and absence of cortisol or lipopolysaccharide. Incubations were performed for 6 or 20h at 4A?C or 10A?C. Lipopolysaccharide did not affect the toxicity of either contaminant. In contrast, cortisol enhanced the toxicity of both environmental contaminants. Hence, stressors that lead to increased cortisol production, but not lipopolysaccharide directly, may increase the toxicity of mercury and Aroclor 1254 to lake trout thymocytes.

Miller, Gregory G.; Sweet, Leonard I.; Adams, Jean V.; Omann, Geneva M.; Passino-Reader, Dora R.; Meier, Peter G.



Use of mucin and hemoglobin in experimental murine Gram-negative bacteremia enhances the immunoprotective action of antibodies reactive with the lipopolysaccharide core region  

Microsoft Academic Search

An antiserum with a high content of antibodies, binding to the Gram-negative lipopolysaccharide core region, was prepared by immunizing rabbits with the rough Escherichia coli mutant J5. This antiserum was capable of protecting mice against lethal challenge doses of E. coli 0 111: B4 in a mouse model where the animals were compromised by means of mucin plus hemoglobin (LD

B. J. Appelmelk; A. M. J. J. Verwey-Van Vught; J. J. Maaskant; W. F. Schouten; L. G. Thijs; D. M. Maclaren



Evaluation of Quantification Methods of Occupational Endotoxin Exposure  

Microsoft Academic Search

Endotoxin has been identified as important component of organic-dust exposure and is suspected as main cause of work-related adverse health effects in dusty areas. Although the determination of endotoxin levels by using the Limulus amoebocyte lysate (LAL) assay is internationally accepted, reliability and variation of values measured with this test remain a point of discussion. Therefore, the purpose of the

V. Liebers; M. Raulf-Heimsoth; G. Linsel; N. Goldscheid; M. Düser; H. Stubel; Th. Brüning



Metropolitan home living conditions associated with indoor endotoxin levels  

Microsoft Academic Search

Background: Household endotoxin exposure in allergy and asthma has been gaining attention for its dual potential to exacerbate these conditions in individuals with established disease and to abrogate atopy before disease onset. Objective: We sought to better understand the home environmental and lifestyle factors influencing house dust endotoxin levels. Methods: From the homes of 86 infants with wheeze in metropolitan

Jose E. Gereda; Mary D. Klinnert; Marcie R. Price; Donald Y. M. Leung; Andrew H. Liu



Expression of a Bacillus thuringiensis ?-endotoxin gene by Bacillus pumilus  

Microsoft Academic Search

The ?-endotoxin genes from Bacillus thuringiensis were introduced into a rhizosphere-inhabiting Bacillus pumilus isolate to create a ?-endotoxin expression and delivery system for subterranean feeding insects such as the larvae of pale western cutworm (Agrotis orthogonia Morrison (Lepidoptera: Noctuidae)). Preliminary experiments indicated that Bacillus thuringiensis subsp. kurstaki cultures were toxic to pale western cutworm larvae. Three different cry genes from

L. B. Selinger; G. G. Khachatourians; J. R. Byers; M. F. Hynes




EPA Science Inventory

Lime addition is a common practice for treating biosolids in order to meet EPA 503 requirements for land application. Since this treatment kills the majority of microorganisms, will it increase the level of endotoxins present in biosolids? And, if endotoxin levels are increased, ...


Endotoxin and Acute Renal Failure Associated with Obstructive Jaundice  

Microsoft Academic Search

A single dose of endotoxin given to rats with obstructive jaundice produced death with intravascular coagulation. This action was apparently due to delayed clearance of endotoxin from the circulation. The finding is relevant to “hepatorenal failure,” which can be caused by bacteraemia after biliary tract operations.

E. N. Wardle; N. A. Wright



Lipoteichoic Acids from Lactobacillus johnsonii Strain La1 and Lactobacillus acidophilus Strain La10 Antagonize the Responsiveness of Human Intestinal Epithelial HT29 Cells to Lipopolysaccharide and Gram-Negative Bacteria  

Microsoft Academic Search

Intestinal epithelial cells (IECs) respond to lipopolysaccharide (LPS) from gram-negative bacteria in the presence of the soluble form of CD14 (sCD14), a major endotoxin receptor. Since sCD14 is also known to interact with gram-positive bacteria and their components, we looked at whether sCD14 could mediate their effects on human IECs. To this end, we examined the production of proinflammatory cytokines

Karine Vidal; Anne Donnet-Hughes; Dominique Granato



The Lipopolysaccharide-Binding Protein Is a Secretory Class 1 Acute-Phase Protein Whose Gene Is Transcriptionally Activated by APRF\\/STAT3 and Other Cytokine-Inducible Nuclear Proteins  

Microsoft Academic Search

Acute-phase reactants (APRs) are proteins synthesized in the liver following induction by interleukin-1 (IL-1),IL-6,andglucocorticoids,involvingtranscriptionalgeneactivation.Lipopolysaccharide-bindingprotein (LBP) is a recently identified hepatic secretory protein potentially involved in the pathogenesis of sepsis, capable of binding the bacterial cell wall product endotoxin and directing it to its cellular receptor, CD14. In order to examine the transcriptional induction mechanisms by which the LBP gene is




Urinary trypsin inhibitor protects against systemic inflammation induced by lipopolysaccharide.  


Urinary trypsin inhibitor (UTI), a serine protease inhibitor, has been widely used as a drug for patients with acute inflammatory disorders such as disseminated intravascular coagulation, shock, and pancreatitis in Japan. Recent studies have demonstrated that serine protease inhibitors may play an anti-inflammatory role beyond merely an inhibitory action on neutrophil elastase at the site of inflammation at least in vitro. To clarify the direct contributions of UTI to inflammatory condition in vivo, we analyzed its roles in experimental systemic inflammatory response induced by intraperitoneal administration of lipopolysaccharide (LPS) using UTI deficient (-/-) mice and corresponding wild-type (WT) mice. After LPS (1 mg/kg) challenge, UTI (-/-) mice revealed a significant elevation of plasma fibrinogen and fibrinogen/fibrin degradation products and a decrease in white blood cell counts compared with WT mice. LPS treatment induced more severe neutrophilic inflammation in the lung and the kidney obtained from UTI (-/-) mice than in those from WT mice, which was confirmed by histological examination. The protein levels of proinflammatory mediators, such as macrophage chemoattractant protein (MCP)-1 in the lungs, MCP-1 and keratinocyte chemoattractant (KC) in the kidneys, and interleukin-1beta, macrophage inflammatory protein-2, MCP-1, and KC in the liver, were significantly greater in UTI (-/-) mice than in WT mice after LPS challenge. Our results suggest that UTI protects against systemic inflammatory response and subsequent organ injury induced by bacterial endotoxin, at least partly through the inhibition of the enhanced expression of proinflammatory cytokines and chemokines. PMID:15576631

Inoue, Ken-Ichiro; Takano, Hirohisa; Shimada, Akinori; Yanagisawa, Rie; Sakurai, Miho; Yoshino, Shin; Sato, Hiroyuki; Yoshikawa, Toshikazu



Visualization and analysis of lipopolysaccharide distribution in binary phospholipid bilayers  

SciTech Connect

Lipopolysaccharide (LPS) is an endotoxin released from the outer membrane of Gram-negative bacteria during infections. It have been reported that LPS may play a role in the outer membrane of bacteria similar to that of cholesterol in eukaryotic plasma membranes. In this article we compare the effect of introducing LPS or cholesterol in liposomes made of dipalmitoylphosphatidylcholine/dioleoylphosphatidylcholine on the solubilization process by Triton X-100. The results show that liposomes containing LPS or cholesterol are more resistant to solubilization by Triton X-100 than the binary phospholipid mixtures at 4 {sup o}C. The LPS distribution was analyzed on GUVs of DPPC:DOPC using FITC-LPS. Solid and liquid-crystalline domains were visualized labeling the GUVs with LAURDAN and GP images were acquired using a two-photon microscope. The images show a selective distribution of LPS in gel domains. Our results support the hypothesis that LPS could aggregate and concentrate selectively in biological membranes providing a mechanism to bring together several components of the LPS-sensing machinery.

Henning, Maria Florencia [Instituto de Investigaciones Bioquimicas La Plata (INIBIOLP), CCT-La Plata, CONICET, Facultad de Ciencias Medicas, UNLP, Calles 60 y 120, 1900 La Plata (Argentina)] [Instituto de Investigaciones Bioquimicas La Plata (INIBIOLP), CCT-La Plata, CONICET, Facultad de Ciencias Medicas, UNLP, Calles 60 y 120, 1900 La Plata (Argentina); Sanchez, Susana [Laboratory for Fluorescence Dynamics, University of California-Irvine, Irvine, CA (United States)] [Laboratory for Fluorescence Dynamics, University of California-Irvine, Irvine, CA (United States); Bakas, Laura, E-mail: [Instituto de Investigaciones Bioquimicas La Plata (INIBIOLP), CCT-La Plata, CONICET, Facultad de Ciencias Medicas, UNLP, Calles 60 y 120, 1900 La Plata (Argentina) [Instituto de Investigaciones Bioquimicas La Plata (INIBIOLP), CCT-La Plata, CONICET, Facultad de Ciencias Medicas, UNLP, Calles 60 y 120, 1900 La Plata (Argentina); Departamento de Ciencias Biologicas, Facultad de Ciencias Exactas, UNLP, Calles 47 y 115, 1900 La Plata (Argentina)



Effective Immunomodulatory Treatment of Escherichia coli Experimental Sepsis with Thalidomide  

PubMed Central

Thalidomide, an agent which inhibits biosynthesis of tumor necrosis factor alpha (TNF-?) and which is used to treat a variety of chronic inflammatory conditions, was investigated as therapy for experimental sepsis. Sepsis was induced by intraperitoneal injection of 107 CFU of Escherichia coli per kg of body weight to 80 Wistar rats divided into four groups. Group A consisted of 24 control animals that did not receive any pretreatment, group B consisted of 18 vehicle-treated control animals pretreated with seed oil, group C consisted of 30 rats administered thalidomide diluted in seed oil at a dose of 50 mg/kg 30 min before bacterial challenge, and group D consisted of eight animals that were not challenged with E. coli but that were used for white blood cell count determination. Sepsis was determined by measurement of vital signs before and 6 h after bacterial challenge. After 6 h the animals were killed and blood was sampled for culture; white blood cell count determination; and determination of endotoxin (lipopolysaccharide), TNF-?, interleukin-1? (IL-1?), and IL-6 levels. The levels of these cytokines were also estimated in the supernatants of human monocytes pretreated with thalidomide after exposure to the isolate. Sepsis developed in all vehicle-treated control animals and controls by 6 h after bacterial challenge but in only 10 animals (33.3%) pretreated with thalidomide (P < 0.0001). Six hours after bacterial challenge all animals had similar levels of endotoxemia, IL-1?, and IL-6. The mean white blood cell count for groups A, B, and C were 5,631.1, 2,638.9, and 8,169.3 cells/?l, respectively (P value between groups, <0.0001); the TNF-? levels were 77.3, 107.2, and 26.1 pg/ml, respectively (P values between groups, <0.0001). Pretreatment of human monocytes with thalidomide prevented the secretion of TNF-? and IL-1? but not that of IL-6. It is concluded that thalidomide exerts a considerable anti-inflammatory effect by preventing evolution to sepsis and by decreasing the level of production of TNF-? and therefore deserves to be further evaluated in research for the therapy of sepsis. PMID:12878503

Giamarellos-Bourboulis, Evangelos J.; Poulaki, Helen; Kostomitsopoulos, Nikolaos; Dontas, Ismene; Perrea, Despina; Karayannacos, Panayotis E.; Giamarellou, Helen



Biophysical investigations into the interactions of endotoxins with bile acids.  


The interaction of selected endotoxin preparations (lipid A from Erwinia carotovora and LPS Re and Ra from Salmonella enterica sv. Minnesota strains R595 and R60, respectively) with selected bile acids was investigated biophysically. Endotoxin aggregates were analyzed for their gel-to-liquid crystalline phase behavior, the type of their aggregates, the conformation of particular functional groups, and their Zeta potential in the absence and presence of the bile acids by applying Fourier-transform infrared spectroscopy, differential scanning calorimetry, measurements of the electrophoretic mobility, and synchrotron radiation X-ray scattering. In addition, the ability of the endotoxins to induce cytokines in human mononuclear cells was tested in the absence and presence of varying concentrations of bile acids. The data show that the endotoxin:bile acid interaction is not governed by Coulomb forces, rather a hydrophobic interaction takes place. This leads to an enhanced formation of the inherent cubic aggregate structures of the endotoxins, concomitant with a slight disaggregation, as evidenced by freeze-fracture electron microscopy. Parallel to this, the addition of bile acids increased the bioactivity of lipid A and, to a lower degree, also that of the tested rough mutant LPS at lower concentrations of the endotoxin preparation, a finding similar as reported for the interaction of other agents such as hemoglobin. These data imply that there are general mechanisms that govern the expression of biological activities of endotoxins. PMID:21954318

Fukuoka, Satoshi; Richter, Walter; Howe, Jörg; Andrä, Jörg; Rössle, Manfred; Alexander, Christian; Gutsmann, Thomas; Brandenburg, Klaus



Eicosapentaenoic acid preserves diaphragm force generation following endotoxin administration  

PubMed Central

Introduction Infections produce severe respiratory muscle weakness, which contributes to the development of respiratory failure. An effective, safe therapy to prevent respiratory muscle dysfunction in infected patients has not been defined. This study examined the effect of eicosapentaenoic acid (EPA), an immunomodulator that can be safely administered to patients, on diaphragm force generation following endotoxin administration. Methods Rats were administered the following (n = 5/group): (a) saline, (b) endotoxin, 12 mg/kg IP, (c) endotoxin + EPA (1.0 g/kg/d), and (d) EPA alone. Diaphragms were removed and measurements made of the diaphragm force-frequency curve, calpain activation, caspase activation, and protein carbonyl levels. Results Endotoxin elicited large reductions in diaphragm specific force generation (P < 0.001), and increased diaphragm caspase activation (P < 0.01), calpain activation (P < 0.001) and protein carbonyl levels (P < 0.01). EPA administration attenuated endotoxin-induced reductions in diaphragm specific force, with maximum specific force levels of 27 ± 1, 14 ± 1, 23 ± 1, and 24 ± 1 N/cm2, respectively, for control, endotoxin, endotoxin + EPA, and EPA treated groups (P < 0.001). EPA did not prevent endotoxin induced caspase activation or protein carbonyl formation but significantly reduced calpain activation (P < 0.02). Conclusions These data indicate that endotoxin-induced reductions in diaphragm specific force generation can be partially prevented by administration of EPA, a nontoxic biopharmaceutical that can be safely given to patients. We speculate that it may be possible to reduce infection-induced skeletal muscle weakness in critically ill patients by administration of EPA. PMID:20233404



MitoQ administration prevents endotoxin-induced cardiac dysfunction.  


Sepsis elicits severe alterations in cardiac function, impairing cardiac mitochondrial and pressure-generating capacity. Currently, there are no therapies to prevent sepsis-induced cardiac dysfunction. We tested the hypothesis that administration of a mitochondrially targeted antioxidant, 10-(6'-ubiquinonyl)-decyltriphenylphosphonium (MitoQ), would prevent endotoxin-induced reductions in cardiac mitochondrial and contractile function. Studies were performed on adult rodents (n = 52) given either saline, endotoxin (8 mg x kg(-1) x day(-1)), saline + MitoQ (500 microM), or both endotoxin and MitoQ. At 48 h animals were killed and hearts were removed for determination of either cardiac mitochondrial function (using polarography) or cardiac pressure generation (using the Langendorf technique). We found that endotoxin induced reductions in mitochondrial state 3 respiration rates, the respiratory control ratio, and ATP generation. Moreover, MitoQ administration prevented each of these endotoxin-induced abnormalities, P < 0.001. We also found that endotoxin produced reductions in cardiac pressure-generating capacity, reducing the systolic pressure-diastolic relationship. MitoQ also prevented endotoxin-induced reductions in cardiac pressure generation, P < 0.01. One potential link between mitochondrial and contractile dysfunction is caspase activation; we found that endotoxin increased cardiac levels of active caspases 9 and 3 (P < 0.001), while MitoQ prevented this increase (P < 0.01). These data demonstrate that MitoQ is a potent inhibitor of endotoxin-induced mitochondrial and cardiac abnormalities. We speculate that this agent may prove a novel therapy for sepsis-induced cardiac dysfunction. PMID:19657095

Supinski, G S; Murphy, M P; Callahan, L A



MitoQ administration prevents endotoxin-induced cardiac dysfunction  

PubMed Central

Sepsis elicits severe alterations in cardiac function, impairing cardiac mitochondrial and pressure-generating capacity. Currently, there are no therapies to prevent sepsis-induced cardiac dysfunction. We tested the hypothesis that administration of a mitochondrially targeted antioxidant, 10-(6?-ubiquinonyl)-decyltriphenylphosphonium (MitoQ), would prevent endotoxin-induced reductions in cardiac mitochondrial and contractile function. Studies were performed on adult rodents (n = 52) given either saline, endotoxin (8 mg·kg?1·day?1), saline + MitoQ (500 ?M), or both endotoxin and MitoQ. At 48 h animals were killed and hearts were removed for determination of either cardiac mitochondrial function (using polarography) or cardiac pressure generation (using the Langendorf technique). We found that endotoxin induced reductions in mitochondrial state 3 respiration rates, the respiratory control ratio, and ATP generation. Moreover, MitoQ administration prevented each of these endotoxin-induced abnormalities, P < 0.001. We also found that endotoxin produced reductions in cardiac pressure-generating capacity, reducing the systolic pressure-diastolic relationship. MitoQ also prevented endotoxin-induced reductions in cardiac pressure generation, P < 0.01. One potential link between mitochondrial and contractile dysfunction is caspase activation; we found that endotoxin increased cardiac levels of active caspases 9 and 3 (P < 0.001), while MitoQ prevented this increase (P < 0.01). These data demonstrate that MitoQ is a potent inhibitor of endotoxin-induced mitochondrial and cardiac abnormalities. We speculate that this agent may prove a novel therapy for sepsis-induced cardiac dysfunction. PMID:19657095

Murphy, M. P.; Callahan, L. A.



Increased Nitric Oxide Production Prevents Airway Hyperresponsiveness in Caveolin-1 Deficient Mice Following Endotoxin Exposure  

PubMed Central

Background Caveolin-1, the hallmark protein of caveolae, is highly expressed within the lung in the epithelium, endothelium, and in immune cells. In addition to its classical roles in cholesterol metabolism and endocytosis, caveolin-1 has also been shown to be important in inflammatory signaling pathways. In particular, caveolin-1 is known to associate with the nitric oxide synthase enzymes, downregulating their activity. Endotoxins, which are are composed mainly of lipopolysaccharide (LPS), are found ubiquitously in the environment and can lead to the development of airway inflammation and increased airway hyperresponsiveness (AHR). Methods We compared the acute responses of wild-type and caveolin-1 deficient mice after LPS aerosol, a well-accepted mode of endotoxin exposure, to investigate the role of caveolin-1 in the development of environmental lung injury. Results Although the caveolin-1 deficient mice had greater lung inflammatory indices compared to wild-type mice, they exhibited reduced AHR following LPS exposure. The uncoupling of inflammation and AHR led us to investigate the role of caveolin-1 in the production of nitric oxide, which is known to act as a bronchodilator. The absence of caveolin-1 resulted in increased nitrite levels in the lavage fluid in both sham and LPS treated mice. Additionally, inducible nitric oxide synthase expression was increased in the lung tissue of caveolin-1 deficient mice following LPS exposure and administration of the potent and specific inhibitor 1400W increased AHR to levels comparable to wild-type mice. Conclusions We attribute the relative airway hyporesponsiveness in the caveolin-1 deficient mice after LPS exposure to the specific role of caveolin-1 in mediating nitric oxide production. PMID:24273688

Hsia, Bethany J.; Pastva, Amy M.; Giamberardino, Charles D.; Potts-Kant, Erin N.; Foster, W. Michael; Que, Loretta G.; Abraham, Soman N.; Wright, Jo Rae; Zaas, David W.



FXR agonist GW4064 alleviates endotoxin-induced hepatic inflammation by repressing macrophage activation  

PubMed Central

AIM: To examine the effect of farnesoid X receptor (FXR) activation by GW4064 on endotoxin-induced hepatic inflammation in nonalcoholic fatty liver disease (NAFLD) and the underlying mechanism. METHODS: Six-week-old male C57BL/6 mice were fed a normal diet or a high-fat (HF) diet for 8 wk. HF diet-fed mice were intraperitoneally injected with GW4064 (30 mg/kg) or DMSO (vehicle) once daily for a week and then sacrificed after lipopolysaccharide (LPS, 50 ?g/mouse) administration. Hepatic inflammation, levels of the macrophage marker F4/80, and apoptosis were measured at the end of the study. Additionally, the expression of proinflammatory genes involved in NAFLD (interleukin-6, interleukin-1?, interferon-?, MCP-1) were analyzed by real-time PCR in the murine macrophage cell line RAW 264.7 cultured with or without GW4064 (2 ?mol/L) before treatment with LPS. RESULTS: In patients with NAFLD, the expression of FXR was detected by immunohistochemical staining and the relation between FXR expression and NAFLD activity score (NAS) was analyzed. Activation of FXR by GW4064 alleviated hepatic inflammation induced by endotoxin in a murine NAFLD model fed an HF diet as reflected by reduced serum levels of aspartate aminotransferase and alanine aminotransferase. Apoptosis and proinflammatory cytokine levels in liver tissues were also reduced by GW4064, and GW4064 could reduce induction of proinflammatory cytokines by LPS in vitro. FXR levels were reduced in patients with non-alcoholic steatohepatitis compared with healthy controls and were negatively correlated with NAS. CONCLUSION: FXR activation attenuates LPS-induced hepatic inflammation in murine NAFLD by reducing expression of proinflammatory cytokines in macrophages. PMID:25339829

Yao, Jun; Zhou, Chun-Suo; Ma, Xiong; Fu, Bai-Qing; Tao, Li-Sheng; Chen, Miao; Xu, Ya-Ping



Selective endothelin-A receptor blockade attenuates endotoxin-induced pulmonary hypertension and pulmonary vascular dysfunction  

PubMed Central

Abstract Endothelin-1 is a potent mediator of sepsis-induced pulmonary hypertension (PH). The pulmonary vascular effects of selective blockade of endothelin receptor subtype A (ETAR) during endotoxemia remain unknown. We hypothesized that selective ETAR antagonism attenuates endotoxin-induced PH and improves pulmonary artery (PA) vasoreactivity. Adult male Sprague-Dawley rats (250–450 g) received lipopolysaccharide (LPS; Salmonella typhimurium; 20 mg/kg intraperitoneally) or vehicle 6 hours before hemodynamic assessment and tissue harvest. The selective ETAR antagonist sitaxsentan (10 or 20 mg/kg) or vehicle was injected intravenously 3 hours after receipt of LPS. Right ventricular systolic pressure, mean arterial pressure (MAP), cardiac output (CO), oxygenation (P/F ratio), and serum bicarbonate were measured. Bronchoalveolar lavage (BAL) cell differential and lung wet-to-dry ratios were obtained. Endothelium-dependent and endothelium-independent vasorelaxations were determined in isolated PA rings. PA interleukin (IL)-1?, IL-6, tumor necrosis factor ? (TNF-?), and inducible nitric oxide synthase (iNOS) messenger RNA (mRNA) were measured. LPS caused PH, decreased MAP, CO, and serum bicarbonate, and increased PA IL-1?, IL-6, TNF-?, and iNOS mRNA. Sitaxsentan attenuated sepsis-induced PH and increased MAP. The P/F ratio, CO, serum bicarbonate, and BAL neutrophilia were not affected by sitaxsentan. In isolated PA rings, while not affecting phenylephrine-induced vasocontraction or endothelium-dependent relaxation, sitaxsentan dose-dependently attenuated LPS-induced alterations in endothelium-independent relaxation. PA cytokine mRNA levels were not significantly attenuated by ETAR blockade. We conclude that ETAR blockade attenuates endotoxin-induced alterations in systemic and PA pressures without negatively affecting oxygenation. This protective effect appears to be mediated not by attenuation of sepsis-induced cardiac dysfunction, acidosis, or alveolar inflammation but rather by improved endothelium-independent vasorelaxation. PMID:25006449



Inhibition of tumor necrosis factor and subsequent endotoxin shock by pirfenidone.  


Tumor necrosis factor-alpha (TNF) is an extremely potent cytokine which is involved in the pathogenesis of a number of diseases. Interruption of its synthesis can result in a reduction of inflammation and subsequent pathology. A new experimental drug pirfenidone (5-methyl-L-phenyl-2-(1H)-pyridone, trade name: Deskar) has been reported to have beneficial effects for the treatment of certain fibrotic diseases. The present study describes the inhibition of TNF in vitro as well as the inhibition of circulating TNF in vivo by pirfenidone. Isolated, thioglycollate-induced peritoneal macrophages (Mphi) from C57BL/6 mice were exposed to either lipopolysaccharide (LPS) or mannosylated bovine serum albumin then incubated with 0.1-0.9 mg/ml of pirfenidone. This substance inhibited the production of TNF in a dose-dependent manner as measured by ELISA. One i.p. injection of either 100 or 200 mg/kg pirfenidone inhibited the induction of circulating TNF following a single i.v. injection of LPS. Endotoxin shock was induced in mice using an i.p. injection of galactosamine and LPS. The higher dose of pirfenidone (200 mg/kg) completely inhibited shock and subsequent mortality. Lower doses of pirfenidone or administration either prior to or post challenge only partially inhibited symptoms. These results indicate that pirfenidone is able to inhibit both TNF induction and subsequent endotoxin shock. Additional studies are warranted to establish this drug as a potential treatment for diseases where TNF plays a major role. PMID:9877280

Cain, W C; Stuart, R W; Lefkowitz, D L; Starnes, J D; Margolin, S; Lefkowitz, S S



Resistance of broiler chickens to Escherichia coli respiratory tract infection induced by passively transferred egg-yolk antibodies  

Microsoft Academic Search

Egg-yolk antibodies induced by immunizing hens with selected Escherichia coli antigens were evaluated for their ability to protect broiler chickens against respiratory\\/septicemic disease caused by avian pathogenic E. coli (APEC). Seven groups of broiler breeder hens were vaccinated three times, 1 week apart with live E. coli, killed E. coli, E. coli antigens [lipopolysaccharide (LPS), type 1 pilus adhesin (FimH),

S Kariyawasam; B. N Wilkie; C. L Gyles



Endotoxin tolerance drives neutrophil to infectious site.  


The objective of this randomized animal study and laboratory investigation was to investigate whether lipopolysaccharide tolerance redirects neutrophil migration between organs. Male BALB/c mice received subcutaneous injections of lipopolysaccharide (1 mg/kg) for 5 days, followed by cecal ligation and puncture (CLP). Cytokines and adhesion molecules were measured after tolerance and CLP challenge. Increased numbers of neutrophils were observed in the peritoneal cavity of tolerant mice, which was associated with increased levels of adhesion molecules and chemokines. In contrast, nontolerant mice accumulated higher numbers of neutrophils in the lungs compared with those in the peritoneal cavity. Neutrophil function accessed by hydrogen peroxide production from neutrophils recovered from peritoneal cavity showed that tolerance increased the capacity to produce hydrogen peroxide. Mortality was reduced in tolerant animals. This study demonstrated that tolerance reduces leukocyte accumulation in the lung after CLP by redirecting neutrophils to the site of infection. PMID:24667625

Ariga, Suely Kubo; Abatepaulo, Fátima Bernardes; Melo, Edielle Sant Anna; Velasco, Irineu Tadeu; Pinheiro da Silva, Fabiano; de Lima, Thais Martins; Soriano, Francisco Garcia



The influence of Th1/Th2 and CD4+ regulatory t cells of mesenteric lymph nodes on systemic lipopolysaccharide.  


Our aims were to study the influence of the mesenteric lymph nodes (MLN) of rats on systemic lipopolysaccharide and to identify the factor that affects the intestinal endotoxin translocation. Ninety-six male Wistar rats were randomly divided into a sham-operation group (S group) and a cecal ligation and perforation group (CLP group). Twenty-four hours after modeling, we tested the Th1/Th2 ratio and percentage of CD4+CD25+Foxp3+ Treg in the MLN. At the same time, the lipopolysaccharide (LPS) in the abdominal aortic blood was detected. In the CLP group, the Th1/Th2 ratio was obviously lower than in the S group. Otherwise, the percentage of CD4+CD25+Foxp3+ Treg of the CLP group was significantly higher than the S group. In the abdominal aortic blood, the LPS level of the CLP group was also higher than in the S group. Through correlation analysis, we found that the level of LPS was positively correlated with the percentage of CD4+CD25+Foxp3+ Treg, and negatively correlated with the Th1/Th2 ratio. This model reveals that the immune suppression of the MLN might affect the level of LPS in the abdominal aortic blood, which might play a certain role in affecting the endotoxin translocation. PMID:25119172

Yu, W; Du, H; Fu, Q; Cui, N; Du, X



Estrogen receptor ? mediates the effects of notoginsenoside R1 on endotoxin-induced inflammatory and apoptotic responses in H9c2 cardiomyocytes.  


Estrogen receptors (ERs) are important for preventing endotoxin?induced myocardial dysfunction. Therefore, plant?derived phytoestrogens, which target ERs may also affect endotoxin?induced toxicity in cardiomyocytes. Our previous study revealed that notoginsenoside?R1 (NG?R1), a predominant phytoestrogen from Panax notoginseng, protects against cardiac dysfunction. However, the effects of NG?R1 on cardiomyocytes and the precise cellular/molecular mechanisms underlying its action remain to be elucidated. In the present study, pretreatment with NG?R1 suppressed the lipopolysaccharide (LPS)?induced degradation of inhibitor of nuclear factor??B (NF??B) ?, the activation of NF??B and caspase?3, and the subsequent myocardial inflammatory and apoptotic responses in H9c2 cardiomyocytes. An increase in the mRNA and protein expression of ER? was also observed in the NG?R1?treated cardiomyocytes. However, the expression pattern of ER? remained unaltered. Furthermore, the cardioprotective properties of NG?R1 against LPS?induced apoptosis and the inflammatory response in cardiomyocytes were attenuated by ICI 182780, a non?selective ER? antagonist, and methyl?piperidino?pyrazole, a selective ER? antagonist. These findings suggested that NG?R1 reduced endotoxin?induced cardiomyocyte apoptosis and the inflammatory response via the activation of ER?. Therefore, NG?R1 exerted direct anti?inflammatory and anti?apoptotic effects on the cardiomyocytes, representing a potent agent for the treatment of myocardial inflammation during septic shock. PMID:25738436

Zhong, Lei; Zhou, Xing-Lu; Liu, Yan-Song; Wang, Yi-Min; Ma, Fei; Guo, Bao-Liang; Yan, Zhao-Qi; Zhang, Qing-Yuan



Endotoxin removal with poly(ethyleneimine)-immobilized adsorbers: Sepharose 4B versus flat sheet and hollow fibre membranes.  


Poly(ethyleneimine) was immobilized on poly(vinyl alcohol)-coated nylon flat sheet membranes, poly(vinyl alcohol) and poly(ethylenevinyl alcohol) hollow fibre membranes as well as Sepharose 4B. The resulting poly(ethyleneimine)-immobilized adsorbers were used for removal of E. coli derived endotoxin from buffers and bovine serum albumin solutions. The efficiency of poly(ethyleneimine) proved to be constant over a wide pH range, including phosphate buffered saline. The performance depended upon the matrix type employed: endotoxin clearance factors varied from 100 to 120,000 in protein-free solutions and 40 to 33,000 in solutions of bovine serum albumin using 6000 EU/ml as feed concentration. The best adsorber was the flat sheet membrane-immobilized poly(ethyleneimine), followed by the hollow fibre-immobilized poly(ethyleneimine) and poly(ethyleneimine)-Sepharose. The factors influencing endotoxin clearance were the mass transport (convective systems were superior to the diffusive system), the chemical composition and the surface structure of the underlying matrix. PMID:9613941

Petsch, D; Deckwer, W D; Anspach, F B; Legallais, C; Vijayalakshmi, M



Are the capsaicin-sensitive structures of ventral medulla involved in the temperature response to endotoxin in rats?  


In chronic experiments on rats pretreated with bilateral microinjection of 25 nl 1% capsaicin to the caudal ventrolateral medulla under ketamine-xylazine-acepromazine anesthesia, an enhancement of the temperature response to intraperitoneal application of 3 microg/kg E. coli lipopolysaccharide as compared to animals who received vehicle to the caudal ventrolateral medulla was found. This is indicative of the involvement of the capsaicin-sensitive bulbar structures in thermoregulatory processes during endotoxemia. PMID:9572598

Koulchitsky, S V



Endotoxin (LPS) increases mesenteric vascular resistance (MVR) and bacterial translocation (BT).  


Endotoxemia is responsible for many of the pathophysiologic alterations that occur with Gram-negative sepsis. We utilized a chronic ovine model to determine the hemodynamic disturbances in the gastrointestinal tract during endotoxemia. Sheep with indwelling arterial, venous, and pulmonary arterial catheters were used. An ultrasonic flow probe was placed on the cephalic mesenteric artery. The animals were subjected to: 1) Ringer's lactate infusion (sham n = 6); or 2) 1.5 mcg/kg E. coli endotoxin (n = 6) over over a period of one half hour and were monitored for 48 hours. They were then sacrificed and specimens of mesenteric lymph node, liver, spleen, kidney, and lung obtained for bacteriologic cultures and histologic analysis. Sheep receiving endotoxin showed more than 50% reduction in the mesenteric blood flow. Mesenteric vascular resistance increased while non-mesenteric systemic vascular resistance decreased. The increase in the total systemic vascular resistance, noted during endotoxemia, was thus likely due to the increase in the mesenteric vascular resistance. At autopsy there were positive cultures for microorganism in the mesenteric lymph nodes in six out of six sheep with endotoxemia as compared to one out of six of control. Thus the vasoconstriction in the mesenteric areas may have resulted in bacterial translocation from the GI tract. PMID:2213944

Navaratnam, R L; Morris, S E; Traber, D L; Flynn, J; Woodson, L; Linares, H; Herndon, D N



[Intestinal mucosa injury during experimental endotoxin-induced shock].  


To ascertain tissue oxygenation during conversion from hypo to hyperdynamic state with vascular volume expansion, venous outflow from a segment of ileum was isolated in anesthetized and pump-ventilated endotoxic dogs to measure gut oxygen uptake (VO2), lactate metabolism, intramucosal PCO2 and tissue PO2 (PtiO2). Tissue PO2 was measured by multipoint surface Mehrdraht Dortmund Oberfläche electrodes placed on mucosal and serosal surfaces of gut. Six dogs were infused with 2 E. coli lipopolysaccharide (LPS) in one hour followed by a two hour 0.5 dextran infusion. Two dogs were used as controls and received dextran infusion in order to assess time and hemodilution-dependent effects. LPS infusion resulted in an hypodynamic sepsis with supply limited VO2, increased arterial lactate and increased lactate output by gut. Resuscitation resulted in an hyperdynamic sepsis with improvement of whole-body VO2. In the gut, VO2 remained low and intramucosal PCO2 as well as lactate output remained high, despite increased flow. Gut PtiO2 results suggested blood flow maldistribution with tissue hypoxia in the mucosa despite increased total flow to the gut. Gut VO2, lactate flux, intramucosal PCO2, and tissue PO2 were consistent with regulatory responses that shut down mucosal perfusion and oxygenation in spite of increased blood flow to gut. PMID:7733517

Vallet, B; Curtis, S E; Lund, N; Cain, S M



Determination of the parameters of binding between lipopolysaccharide and chitosan and its N-acetylated derivative using a gravimetric piezoquartz biosensor.  


The interaction of endotoxin (lipopolysaccharide - LPS) with low molecular weight chitosan (5.5kDa), its N-acylated derivative and chitoliposomes was studied using a gravimetric piezoelectric quartz crystal microbalance biosensor. The optimal conditions for the formation of a biolayer based on immobilized LPS on the resonator surface and its regeneration were elaborated. The association and dissociation rate constants for LPS binding to chitosans were determined and the affinity constants (Kaf) were calculated based on the data on changes in the oscillation frequency of the quartz crystal resonator. The Kaf values correlated with the ones obtained using other methods. The affinity of N-acylated chitosan binding to LPS was higher than that of the parent chitosan binding to LPS. Based on the results obtained, we suggest that water-soluble N-acylated derivatives of chitosan with low degree of substitution of amino groups could be useful compounds for endotoxin binding and neutralization. PMID:25637889

Naberezhnykh, G A; Gorbach, V I; Kalmykova, E N; Solov'eva, T F



E. Coli  


... Share Compartir E. coli (Escherichia coli) General Information E. coli O157:H7 Infections Linked to Ground Beef E. coli O121 ... Clover Sprouts Multistate Outbreak of Shiga toxin-producing Escherichia coli O157:H7 Infections Linked to Ground Beef Multistate Outbreak ...


Efficacy of a novel biofilter in hatchery sanitation: I. Removal of airborne bacteria, dust and endotoxin.  


A novel biofilter containing organic, bentonite and halloysite media was applied for elimination of microbial pollutants from the air of an industrial hatchery. The concentrations of total mesophilic bacteria, Gram-negative bacteria, thermophilic actinomycetes, dust and bacterial endotoxin were determined in the air of hatchery during 2 months before installation of the biofilter, and during 6 months after installation of the biofilter, at the inlet and outlet ducts from each medium. Before installation of the biofilter, the concentrations of total mesophilic bacteria, Gram-negative bacteria, thermophilic actinomycetes, dust and endotoxin in the air were within the ranges of 0.97-131.2x10(3) cfu/m3, 0.0-34.4x10(3) cfu/m3, 0.0-0.02x10(3) cfu/m3, 0.37-4.53 mg/m3, and 50.9-520,450.4 ng/m3, respectively. Enterococcus faecalis and Gram-negative bacteria (Acinetobacter spp., Escherichia coli, Enterobacter cloacae, and other species) prevailed among bacterial species recovered from the air of the hatchery. A total of 56 species or genera of bacteria were identified in the air samples taken in the examined hatchery; of these, 11, 11 and 6 species or genera respectively were reported as having allergenic, immunotoxic and/or infectious properties The concentrations of total mesophilic bacteria, Gram-negative bacteria, Enterococcus faecalis and endotoxin found at the inlet duct of the biofilter after its installation were significantly smaller compared to those recorded before its installation (p<0.05). The concentrations of Gram-negative bacteria, Enterococcus faecalis and dust found at the outlet ducts of biofilter after its installation were significantly smaller compared to those recorded at the inlet duct of the biofilter (p<0.01). The concentrations of total meso-philic bacteria were also smaller at the outlet ducts of the biofilter compared to that at the inlet duct; however, the difference was not significant because of the massive growth of Streptomyces species in the biofilter's media which contaminated the outcoming air. In conclusion, the applied biofilter proved to be effective in the elimination of potentially pathogenic bacteria, dust and endotoxin from the air of the hatchery. The efficacy of the biofilter could be improved by the inhibition of the Streptomyces growth in the media of the biofilter. PMID:17655192

Chmielowiec-Korzeniowska, Anna; Tymczyna, Leszek; Skórska, Czes?awa; Sitkowska, Jolanta; Cholewa, Grazyna; Dutkiewicz, Jacek



TLR4 gene variants modify endotoxin effects on asthma  

Microsoft Academic Search

Background: Environmental exposure to endotoxin might have a crucial role in immune maturation and development of asthma. Objective: The aim of this study was to investigate whether the effect of endotoxin concentration in settled house dust on asthma is modified by the presence of variation in the TLR4 gene. Methods: We performed a cross-sectional study within the German follow-up of

Monika Werner; Rebekka Topp; Katrin Wimmer; Kai Richter; Wolfgang Bischof; Matthias Wjst; Joachim Heinrich



Endotoxin-stimulated innate immunity: A contributing factor for asthma  

Microsoft Academic Search

Exposure to airborne endotoxin in infancy may protect against asthma by promoting enhanced TH1 response and tolerance to allergens. On the other hand, later in life, it adversely affects patients with asthma. Endotoxin binding to receptors on macrophages and other cells generates IL-12, which inhibits IgE responses. It also generates cytokines like IL-1, TNF-?, and IL-8, which cause inflammation. These

Charles E. Reed; Donald K. Milton



Alcohol feeding and lipopolysaccharide injection modulate apoptotic effectors in the rat pancreas in vivo.  


The purpose of this study was to determine if alcohol consumption and endotoxin injection change the rate of apoptosis in the pancreas. Rats were fed a Lieber-DeCarli diet for 14 weeks. At 14 weeks, the animals were injected with lipopolysaccharide (LPS) or saline and killed. The pancreata were resected and snap frozen. Apoptosis was detected by TUNEL assay. Caspase-3 activity, Bcl-2 (protein), and Fas ligand (mRNA) were assayed in pancreas extracts and alpha-amylase in plasma. Alcohol feeding significantly decreased alpha-amylase and caspase-3 activity, and significantly increased Bcl-2. LPS injection increased caspase-3 activity and decreased Bcl-2. Fas ligand mRNA was increased only in alcohol-fed, LPS-injected rats. TUNEL labeling was significantly increased only in alcohol-fed, LPS-injected rats. These data show that (a) long-term alcohol feeding suppresses apoptosis in the pancreas; (b) LPS increases the rate of apoptosis in the pancreas; (c) caspase-3 activity and Bcl-2 expression change in opposite directions; (d) TUNEL positivity and Fas ligand expression are increased, and Bcl-2 is decreased in ethanol-fed + LPS-injected rats. These results suggest that prolonged alcohol consumption may sensitize acinar cells to endotoxin-induced injury and raise the possibility that a similar mechanism may cause pancreatitis in human alcoholics. PMID:10975712

Fortunato, F; Gates, L K



Lipopolysaccharide Inhibits the Channel Activity of the P2X7 Receptor  

PubMed Central

The purinergic P2X7 receptor (P2X7R) plays an important role during the immune response, participating in several events such as cytokine release, apoptosis, and necrosis. The bacterial endotoxin lipopolysaccharide (LPS) is one of the strongest stimuli of the immune response, and it has been shown that P2X7R activation can modulate LPS-induced responses. Moreover, a C-terminal binding site for LPS has been proposed. In order to evaluate if LPS can directly modulate the activity of the P2X7R, we tested several signaling pathways associated with P2X7R activation in HEK293 cells that do not express the TLR-4 receptor. We found that LPS alone was unable to induce any P2X7R-related activity, suggesting that the P2X7R is not directly activated by the endotoxin. On the other hand, preapplication of LPS inhibited ATP-induced currents, intracellular calcium increase, and ethidium bromide uptake and had no effect on ERK activation in HEK293 cells. In splenocytes-derived T-regulatory cells, in which ATP-induced apoptosis is driven by the P2X7R, LPS inhibited ATP-induced apoptosis. Altogether, these results demonstrate that LPS modulates the activity of the P2X7R and suggest that this effect could be of physiological relevance. PMID:21941410

Leiva-Salcedo, Elias; Coddou, Claudio; Rodríguez, Felipe E.; Penna, Antonello; Lopez, Ximena; Neira, Tanya; Fernández, Ricardo; Imarai, Mónica; Rios, Miguel; Escobar, Jorge; Montoya, Margarita; Huidobro-Toro, J. Pablo; Escobar, Alejandro; Acuńa-Castillo, Claudio



Interactions of a designed peptide with lipopolysaccharide: Bound conformation and anti-endotoxic activity  

SciTech Connect

Designed peptides that would selectively interact with lipopolysaccharide (LPS) or endotoxin and fold into specific conformations could serve as important scaffolds toward the development of antisepsis compounds. Here, we describe solution structure of a designed amphipathic peptide, H{sub 2}N-YVKLWRMIKFIR-CONH{sub 2} (YW12D) in complex with endotoxin as determined by transferred nuclear Overhauser effect spectroscopy. The conformation of the isolated peptide is highly flexible, but undergoes a dramatic structural stabilization in the presence of LPS. Structure calculations reveal that the peptide presents two amphipathic surfaces in its bound state to LPS whereby each surface is characterized by two positive charges and a number of aromatic and/or aliphatic residues. ITC data suggests that peptide interacts with two molecules of lipid A. In activity assays, YW12D exhibits neutralization of LPS toxicity with very little hemolysis of red blood cells. Structural and functional properties of YW12D would be applicable in designing low molecular weight non-toxic antisepsis molecules.

Bhunia, Anirban; Chua, Geok Lin; Domadia, Prerna N. [School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551 (Singapore); Warshakoon, Hemamali; Cromer, Jens R.; David, Sunil A. [Department of Medicinal Chemistry, University of Kansas, 2030 Becker Drive, Lawrence, KS 66047 (United States); Bhattacharjya, Surajit [School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551 (Singapore)], E-mail:



Membrane adsorbers for selective removal of bacterial endotoxin.  


Surface-modified flat-sheet microfiltration membranes were functionalised with poly-L-lysine, polymyxin B, poly(ethyleneimine), L-histidine, histamine, alpha-amylase and DEAE as well as deoxycholate. Their suitability to remove endotoxin from both buffers and protein solutions was examined using bovine serum albumin, murine IgG1 and lysozyme as model proteins. In protein-free solutions reduction from 6000 EU/ml to <0.1 EU/ml was achieved with all applied ligands; only alpha-amylase as well as L-histidine and histamine, when immobilized via the non-ionic spacer bisoxirane, exhibited low clearance factors at neutral pH. The adsorption of endotoxin is mainly ruled by electrostatic interaction forces. Thus in multi-component systems, such as endotoxin-contaminated protein solutions, competing interactions take place: acidic proteins compete with endotoxin for binding sites at the membrane adsorbers, basic proteins compete with the ligands for endotoxin and act as endotoxin carriers. With properly chosen conditions the membrane adsorbers presented here show exceptional effectiveness also in the presence of proteins. They are generally superior to functionalised Sepharose chromatographic sorbents and allow fast processing. They may contribute to reduce the risks in the application of parenterals and diagnostics. PMID:9200521

Petsch, D; Beeskow, T C; Anspach, F B; Deckwer, W D



Pretreatment of lipopolysaccharide (LPS) ameliorates D-GalN/LPS induced acute liver failure through TLR4 signaling pathway  

PubMed Central

Endotoxin tolerance (ET) is an important phenomenon, which affects inflammation and phagocytosis. Pretreatment with low dose of lipopolysaccharide (LPS) can protect liver injury from various hepatotoxicants such as acetaminophen and pseudomonas aeruginosa exotoxin A. The current study aimed to investigate the protecting mechanisms of endotoxin tolerance in acute liver failure induced by D-galactosamine (D-GalN)/LPS and possible role of toll-like receptors 4 (TLR4) signaling pathway in this phenomenon. Acute liver failure was induced by Injection of D-GalN/LPS. To mimic endotoxin tolerance, male Sprague-Dawley rats were treated with low dose of LPS (0.1 mg/kg once a day intraperitoneally for consecutive five days) before subsequent injection of D-GalN/LPS. Rat survival was determined by survival rate. Liver injury was confirmed by serum biochemical and liver histopathological examination. Inflammatory cytokines were determined by ELISA and nuclear factor-kappa B (NF-?B) (P65), toll-like receptors 4 (TLR4) and Interleukin-1 receptor-associated kinase-1 (IRAK-1) were measured by reverse transcriptase polymerase chain reaction and western blot respectively. Pretreatment of LPS significantly improved rat survival. Moreover, rats pretreated with LPS exhibited lower serum enzyme (ALT, AST and TBiL) level, lower production of inflammatory cytokines and more minor liver histopathological damage than rats without pretreatment of LPS. LPS pretreatment suppressed production of TLR4 and IRAK-1. LPS pretreatment also inhibited activation of hepatic NF-?B. These results indicated that endotoxin tolerance contributed to liver protection against D-GalN/LPS induced acute liver failure through down-regulation of TLR4 and NF-?B pathway. PMID:25400741

Zhang, Sainan; Yang, Naibin; Ni, Shunlan; Li, Wenyuan; Xu, Lanman; Dong, Peihong; Lu, Mingqin



Endotoxin contamination of apolipoprotein A-I: Effect on macrophage proliferation - A cautionary tale.  


This technical report addresses the problem of endotoxin contamination of apolipoprotein reagents. Using a bromodeoxyuridine incorporation cell proliferation assay, we observed that human plasma ApoA-I as low as 1 ?g/ml resulted in a >90% inhibition in macrophage proliferation. However, not all ApoA-I from different sources showed this effect. We considered the possibility that endotoxin contamination of the apolipoproteins contributed to the differential inhibition of macrophage cell proliferation. Endotoxin alone very potently inhibited macrophage proliferation (0.1 ng/ml inhibited macrophage proliferation >90%). Measurement of endotoxin levels in the apolipoprotein products, including an analysis of free versus total endotoxin, the latter which included endotoxin that was masked due to binding to protein, suggested that free endotoxin mediated inhibition of macrophage proliferation. Despite the use of an advanced endotoxin removal procedure and agents commonly used to inhibit endotoxin action, the potency of endotoxin precluded successful elimination of endotoxin effect. Our findings show that endotoxin contamination can significantly influence apparent apolipoprotein-mediated cell effects (or effects of any other biological products), especially when these products are tested on highly endotoxin-sensitive cells, such as macrophages. PMID:25778625

Jin, Xueting; Xu, Qing; Champion, Keith; Kruth, Howard S



Effects of the immunomodulator, VGX-1027, in endotoxin-induced uveitis in Lewis rats  

PubMed Central

Background and purpose: VGX-1027 is a novel, low molecular weight, immunomodulatory compound that has shown efficacy against a variety of immuno-inflammatory disease models in animals including autoimmune diabetes in NOD mice, collagen-induced arthritis and chemically induced inflammatory colitis. Here, we have studied the effects of VGX-1027 on the development of endotoxin-induced uveitis (EIU) in male Lewis rats, as a model of inflammatory ocular diseases in humans. Experimental approach: EIU was induced by a single footpad injection of 200??g lipopolysaccharide (LPS). Groups of rats were treated with either VGX-1027 (25?mg?kg?1) or its vehicle at different time points (30?min, 6?h or 12?h) after the challenge with LPS or, as positive control, with dexamethasone. The rats were killed within 16?h after LPS challenge, and the eyes and aqueous humor were collected to study serological, immunological and histological signs of EIU. Key results: The rats treated with VGX-1027 within 6?h after LPS challenge exhibited milder clinical, histological and laboratory signs of EIU than those treated with vehicle. Conclusion and implications: This study provides the first evidence that systemic treatment with VGX-1027 counteracts the uveitis-inducing effect of LPS in rats and suggests that this drug may have potential in the treatment of immuno-inflammatory conditions of the eye in humans. PMID:18776919

Mangano, K; Sardesai, N Y; Quattrocchi, C; Mazzon, E; Cuzzocrea, S; Bendtzen, K; Meroni, P L; Kim, J J; Nicoletti, F



The Aldosterone-Mineralocorticoid Receptor Pathway Exerts Anti-Inflammatory Effects in Endotoxin-Induced Uveitis  

PubMed Central

We have previously shown that the eye is a mineralocorticoid-sensitive organ and we now question the role of mineralocorticoid receptor (MR) in ocular inflammation. The endotoxin-induced uveitis (EIU), a rat model of human intraocular inflammation, was induced by systemic administration of lipopolysaccharide (LPS). Evaluations were made 6 and 24 hours after intraocular injection of aldosterone (simultaneous to LPS injection). Three hours after onset of EIU, the MR and the glucocorticoid metabolizing enzyme 11-beta hydroxysteroid dehydrogenase type 2 (11?-HSD2) expression were down-regulated in iris/ciliary body and the corticosterone concentration was increased in aqueous humor, altering the normal MR/glucocorticoid receptor (GR) balance. At 24 hours, the GR expression was also decreased. In EIU, aldosterone reduced the intensity of clinical inflammation in a dose-dependent manner. The clinical benefit of aldosterone was abrogated in the presence of the MR antagonist (RU26752) and only partially with the GR antagonist (RU38486). Aldosterone reduced the release of inflammatory mediators (6 and 24 hours: TNF-?, IFN-?, MIP-1?) in aqueous humor and the number of activated microglia/macrophages. Aldosterone partly prevented the uveitis-induced MR down-regulation. These results suggest that MR expression and activation in iris/ciliary body could protect the ocular structures against damages induced by EIU. PMID:23152847

Ly, André; Leroux les Jardins, Guillaume; Goldenberg, Brigitte; Naud, Marie-Christine; Jonet, Laurent; Besson-Lescure, Bernadette; Jaisser, Frederic; Farman, Nicolette; De Kozak, Yvonne; Behar-Cohen, Francine



[Effects of isepamicin and beta-lactam antibiotics on the release of endotoxin from Pseudomonas aeruginosa].  


Antibiotic-induced release of endotoxin (lipopolysaccharide, LPS) from Pseudomonas aeruginosa was investigated in in vitro with different antibiotic concentrations and in the pharmacokinetic autosimulation system. We compared the effect of isepamicin (ISP) with those of 3 beta-lactam antibiotics, piperacillin (PIPC), ceftazidime (CAZ) and imipenem (IPM). ISP showed a strong bactericidal activity, but the amount of free LPS did not increase by 6 hrs (28 +/- 2 ng/ml at 1MIC). PIPC and CAZ caused a gradual killing and a large amount of LPS release at 4 hrs (515 ng/ml and 493 ng/ml, respectively, at 1 MIC). At 1/4 x MIC, PIPC and CAZ did not reduce colony forming counts and induced more release of free LPS. The organism treated with IPM released less LPS, while it was killed rapidly. The viable cell counts decreased dramatically after administration of ISP in the pharmacokinetic autosimulation system. ISP inhibited the bacterial regrowth and the following release of free LPS by 8 hrs. Great amounts of free LPS were released 4 hrs after the administration of PIPC and CAZ in the simulation system, associated with morphological changes; elongation, cell lysis or regrowth. IPM showed a strong bactericidal activity and less liberation of free LPS, but the free LPS level increased at 8 hrs, accompanied by the regrowth of the organism. The total amounts of LPS released by P. aeruginosa PAO1 in 8 hours of the pharmacokinetic simulation system were as follows; ISP < IPM < CAZ < PIPC. PMID:10202687

Yamaguchi, S; Sato, S; Toriya, M; Tsuji, A



Effect of chitinase inhibitors on endotoxin-induced uveitis (EIU) in rabbits.  


The acidic mammalian chitinase (AMCase) is significantly increased in tears of human allergic conjunctivitis. The aim of the study was to investigate the effects of chitinase inhibitors, allosamidin and caffeine versus dexamethasone, in rabbit endotoxin-induced uveitis (EIU). EIU was induced in rabbits by a single intravitreal injection of 100ng/10microl lipopolysaccharide (LPS). Drugs at four different concentrations (0.1, 0.01, 0.001 and 0.0001mM) were topically applied to the rabbit eye five times in 24h. Tears were collected at 0, 6 and 24h after LPS to measure the AMCase activity. The effect of treatment was also evaluated at the same time by slit lamp examination. Tear AMCase activity increased 6 and 24h after LPS injection. The AMCase activity was significantly inhibited in all treated groups with all doses of allosamidin and caffeine except with the lowest concentration. A higher AMCase inhibition at 24h was found with allosamidin and caffeine compared to dexamethasone. Moreover, topical administration of allosamidin, caffeine and dexamethasone produced a remarkable reduction of inflammatory signs, in the order: dexamethasone>caffeine>allosamidin. AMCase inhibitors showed in this rabbit model of uveitis a notable control of inflammatory response with a significant reduction of AMCase activity in tears with caffeine and allosamidin. These results support the key role of AMCase in the pathogenesis of human ocular inflammatory diseases and the therapeutic effect of AMCase inhibitors on experimental uveitis. PMID:18353673

Bucolo, Claudio; Musumeci, Maria; Maltese, Adriana; Drago, Filippo; Musumeci, Salvatore



Cerebrovascular responses in the fetal sheep brain to low-dose endotoxin.  


Clinical and experimental evidence indicate that infection in pregnancy is associated with fetal brain damage. However, the inflammatory processes that compromise the fetal brain are not fully understood. In this study, we used a single, low dose of lipopolysaccharide (LPS, 0.1 microg/kg i.v.) to provoke an acute-phase response in unanesthetized fetal sheep in utero. COX-2 mRNA was increased in the cortex and cerebellum at 24 and 48 h after LPS, and immunoreactive COX-2 protein was increased in perivascular cells throughout gray and white matter at 24 h after LPS administration. Plasma albumin was observed in the parenchyma of the brain in cortex, thalamus, hypothalamus, corpus callosum, fornix, hippocampus, midbrain, subcallosal bundle, and cerebellar Purkinje cells. Large, rounded, lectin-positive cells with the appearance of macrophages were observed around blood vessels in subventricular white matter. These results indicate that blood-brain barrier permeability is increased in the fetal brain after exposure to endotoxin and suggests that cytotoxic and pro-inflammatory substances could pass from the circulation into the brain after peripheral inflammatory stimulation. PMID:14973172

Yan, Edwin; Castillo-Meléndez, Margie; Nicholls, Trisha; Hirst, Jonathan; Walker, David



?-Cyclodextrin-polyurethane copolymer adsorbent for selective removal of endotoxin from DNA solution.  


Copolymer particles for removal of endotoxins (lipopolysaccharides, LPSs) were prepared by suspension copolymerization of ?-cyclodextrin (CyD) and 1,6-hexamethylenediisocyanate. The LPS-removing activity of the copolymer particles was compared with that of poly(?-lysine)-immobilized Cellufine (cationic adsorbent) or polystyrene particles (hydrophobic adsorbent) by a batch method. When DNA was present in solution with LPSs under physiological conditions (pH 6.0, ionic strength of ? = 0.05-0.8), LPS-removing activity of the cationic or hydrophobic adsorbent was unsatisfactory because both the DNA and the LPSs were adsorbed onto each adsorbent. By contrast, the copolymer particles with ?-CyD cavity (CyD content: 14-20 mol%) could selectively remove LPSs from a DNA solution (50 ?g ml(-1), pH 6.0, and ? = 0.05-0.2) containing LPSs (15 EU ml(-1)) without the adsorption of DNA. The residual concentration of LPSs in the treated DNA solution was below 0.1 EU ml(-1), and the recovery of DNA was 99%. PMID:23969015

Sakata, Masayo; Uezono, Koji; Kimura, Kasane; Todokoro, Masami




EPA Science Inventory

Background: Recent epidemiologic and in vivo studies have suggested that inhaled endotoxin plays an important role in asthma pathogenesis. Objective: The present study examines the effect of nasal allergen provocation on subsequent endotoxin challenges in subjects with atopi...



EPA Science Inventory

Endotoxin exposure has been associated with both protection against development of TH2-immune responses during childhood and exacerbation of asthma in persons who already have allergic airway inflammation.1 Occupational and experimental inhalation exposures to endotoxin have been...


Ragweed pollen extract intensifies lipopolysaccharide-induced priming of NLRP3 inflammasome in human macrophages  

PubMed Central

Ragweed pollen extract (RWE) possesses intrinsic NADPH oxidase activity that induces oxidative stress by initiating the production of intracellular reactive oxygen species (ROS). The ROS are important contributors to the manifestation of allergic inflammation; furthermore, concomitant exposure to an allergen and an endotoxin trigger a stronger inflammatory response. One of the main pro-inflammatory cytokines produced in inflammatory responses is interleukin-1? (IL-1?), and its production is associated with caspase-1-containing inflammasome complexes. Intracellular ROS have been implicated in NLRP3 inflammasome-mediated IL-1? production, therefore, we aimed to study whether RWE influences the function of NLRP3 inflammasome. Here we describe that, in the presence of NADPH, RWE significantly elevates lipopolysaccharide-induced IL-1? production of THP-1 cells as well as human primary macrophages and dendritic cells. We also demonstrate that increased IL-1? production is mediated through NLRP3 inflammasome in THP-1 macrophages. We provide evidence that RWE elevates cytosolic ROS level in these cells, and ROS inhibitors abolish IL-1? production. Furthermore, we show that RWE enhances lipopolysaccharide-induced gene transcription/expression of pro-IL-1? and key components of the inflammasome via a ROS-dependent mechanism. PMID:23278511

Varga, Aliz; Budai, Marietta M; Milesz, Sándor; Bácsi, Attila; T?zsér, József; Benk?, Szilvia



Occurrence of endotoxins in groundwater during the land application of wastewater  

Microsoft Academic Search

Since sewage may contain high concentrations of bacterial endotoxin, the occurrence of endotoxin in groundwater underlying five sewage land application sites was studied. Endotoxin concentrations were found to range from 0.3 to 480 ng\\/ml in wells 3 to 37 m beneath these sites. Although these concentrations were higher than the native groundwater, a 90% to 99.9% reduction in endotoxin occurred

Sagar M. Goyal; Charles P. Gerba



Prevention of cardiac damage induced by formyl-leurosine, a potent cytostatic agent, by radio-detoxified endotoxin (Tolerin) in dogs  

SciTech Connect

Radio-detoxified endotoxin (Tolerin), produced by /sup 60/Co-gamma irradiation of Escherichia coli 089 endotoxin, can protect dogs against the acute cardiotoxic side-effects of formyl-leurosine, a semi-synthetic Vinca derivative with promising antineoplastic potency. Formyl-leurosine induces a rapid decrease in arterial blood pressure and diminishes the contractile force of the myocardium in the anaesthetized dog. These responses indicate a direct pharmacologic relaxant effect of the drug on the heart and vasculature smooth muscle. The early cardiovascular depression is of short duration and is unaffected by Tolerin. Tolerin can prevent, however, the secondary, more dangerous phase of circulatory depression that is associated with the severe cardiotoxic manifestations of the drug, as demonstrated by hemodynamic and morphologic (light and electronmicroscopic) patterns.

Bertok, L.; Juhasz-Nagy, A.; Sotonyi, P.



Lipopolysaccharide mutants of Rhizobium meliloti are not defective in symbiosis  

SciTech Connect

Mutants of Rhizobium meliloti selected primarily for bacteriophage resistance fall into 13 groups. Mutants in the four best-characterized groups (class A, lpsB, lpsC, and class D), which map to the rhizobial chromosome, appear to affect lipopolysaccharide (LPS) as judged by the reactivity with monoclonal antibodies and behavior on sodium dodecyl sulfate-polyacrylamide gels of extracted LPS. Mutations in all 13 groups, in an otherwise wild-type genetic background, are Fix{sup +} on alfalfa. This suggests that LPS does not play a major role in symbiosis. Mutations in lpsB, however, are Fix{sup {minus}} in one particular genetic background, evidently because of the cumulative effect of several independent background mutations. In addition, an auxotrophic mutation evidently equivalent to Escherichia coli carAB is Fix{sup {minus}} on alfalfa.

Clover, R.H.; Kieber, J.; Signer, E.R. (Massachusetts Institute of Technology, Cambridge (USA))



Influence of Different Cleaning Practices on Endotoxin Exposure at Sewage Treatment Plants  

Microsoft Academic Search

Exposure to endotoxin at sewage treatment plants is associated with an increased prevalence of work-related symptoms in sewage workers. Since cleaning activities are regarded as an import- ant determinant of endotoxin exposure, workers' endotoxin exposure levels during different cleaning activities were compared in an experimental setting. Variables considered were water used (tap water, surface water or effluent), water pressure (low




Exposure to airborne endotoxins among sewer workers: an exploratory study.  


Exploratory bioaerosol sampling was performed in order to assess exposure to airborne endotoxins during sewer work. Personal samples were collected in underground sewer pipes using 37-mm closed-face cassettes containing fibreglass filters (CFC-FG method) or polycarbonate filters (CFC-PC method). Endotoxins were quantified using the limulus amoebocyte lysate assay. Concentrations of airborne endotoxins at sewer workplaces (16-420 EU m(-3)) were higher than those measured outside the sewer network (0.6-122 EU m(-3)). Sewer worker exposure to airborne endotoxins depended on the workplace and on the tasks. Exposure levels were the highest for tasks involving agitation of water and matter, especially for 'chamber cleanup' and 'pipes cleanup' with a high-pressure water jet. Airborne endotoxin levels at the workplace tended to be higher when CFC-FG was used as the sampling method rather than CFC-PC. The adjusted mean of the measured concentrations for CFC-PC represents 57% of the mean observed with CFC-FG. The number of samples collected in the descriptive study was too low for drawing definitive conclusions and further exposure investigations are needed. Therefore, our exploratory study provides new exposure data for the insufficiently documented sewer working environment and it would be useful for designing larger exposures studies. PMID:24470536

Duquenne, Philippe; Ambroise, Denis; Görner, Pierre; Clerc, Frédéric; Greff-Mirguet, Guylaine



Loss of hepatic venous responsiveness after endotoxin in anesthetized cats.  


Endotoxin (from Salmonella enteriditis ) was administered either as an intravenous bolus injection after administration of indomethacin to prevent the acute anaphylactoid response or as a slow intravenous infusion to cats anesthetized with pentobarbital. Within 30 min, hepatic blood volume measured by plethysmography increased by 30%. However, unlike the outflow block seen in dogs after endotoxin, this increase in blood volume was associated with a fall in portal and hepatic lobar venous pressures. Responses to hepatic nerve stimulation (1-8 Hz), to intravenous infusions of norepinephrine (0.2-1.0 microgram X kg-1 X min-1), and to infusions into the hepatic artery of norepinephrine (0.1-0.5 microgram X kg-1 X min-1) and angiotensin II (0.1-0.5 microgram X kg-1 X min-1) were compared before and 150 min after endotoxin administration. Both portal pressure and hepatic blood volume responses to these stimuli were markedly depressed by 150 min after endotoxin. We conclude that in cats endotoxin causes a markedly depressed responsiveness of hepatic venous smooth muscle to agonists and a modest pooling of blood in the liver probably due to impairment of preexisting sympathetic tone. Although these hepatic venous effects were observed at a time when cardiac output was not markedly depressed, it is suggested that they may play a significant role in the later development of reduced cardiac output and shock. PMID:6372524

Seaman, K L; Greenway, C V



Impaired phagocyte responses to lipopolysaccharide in paroxysmal nocturnal hemoglobinuria.  


Bone marrow-derived cells from patients suffering from paroxysmal nocturnal hemoglobinuria (PNH) show a defect in the expression of phosphatidylinositol-anchored membrane proteins, including the CD14 molecule. Blocking experiments with anti-CD14 monoclonal antibodies have shown that lipopolysaccharide (LPS)-induced tumor necrosis factor alpha production by monocytes depends on the interaction between CD14 and a complex formed by LPS and LPS-binding protein. We used a whole-blood model to examine the LPS-induced production of tumor necrosis factor alpha and interleukin-6 in PNH patients and healthy volunteers. At low endotoxin concentrations (1 ng/ml), PNH patients displayed a marked defect in the production of both cytokines, whereas at high LPS concentrations (100 ng/ml), cytokine production was similar to that in healthy volunteers. Using flow cytometry, we also studied the expression of the adhesion molecules Mac-1 (CD11b/CD18) and ICAM-1 (CD54) by monocytes and granulocytes after LPS stimulation. Compared with phagocytes from healthy volunteers, CD14-deficient cells showed poor Mac-1 and ICAM-1 upregulation when whole blood was stimulated with LPS (1 ng/ml), whereas their response to higher LPS doses (100 and 1,000 ng/ml) was essentially normal. The importance of the CD14 molecule in the activation of phagocytes by low LPS concentrations was confirmed by the inhibitory effect of an anti-CD14 antibody both in healthy volunteers and in PNH patients. Since these patients produce the soluble form of the CD14 molecule, these data suggest that soluble CD14 could play a role in phagocyte responses to LPS. We conclude that, in whole blood, phagocytes from PNH patients show impaired responsiveness to LPS and this phenomenon is most probably related to their defect in expression of membrane CD14. PMID:7691746

Duchow, J; Marchant, A; Crusiaux, A; Husson, C; Alonso-Vega, C; De Groote, D; Neve, P; Goldman, M



Impaired phagocyte responses to lipopolysaccharide in paroxysmal nocturnal hemoglobinuria.  

PubMed Central

Bone marrow-derived cells from patients suffering from paroxysmal nocturnal hemoglobinuria (PNH) show a defect in the expression of phosphatidylinositol-anchored membrane proteins, including the CD14 molecule. Blocking experiments with anti-CD14 monoclonal antibodies have shown that lipopolysaccharide (LPS)-induced tumor necrosis factor alpha production by monocytes depends on the interaction between CD14 and a complex formed by LPS and LPS-binding protein. We used a whole-blood model to examine the LPS-induced production of tumor necrosis factor alpha and interleukin-6 in PNH patients and healthy volunteers. At low endotoxin concentrations (1 ng/ml), PNH patients displayed a marked defect in the production of both cytokines, whereas at high LPS concentrations (100 ng/ml), cytokine production was similar to that in healthy volunteers. Using flow cytometry, we also studied the expression of the adhesion molecules Mac-1 (CD11b/CD18) and ICAM-1 (CD54) by monocytes and granulocytes after LPS stimulation. Compared with phagocytes from healthy volunteers, CD14-deficient cells showed poor Mac-1 and ICAM-1 upregulation when whole blood was stimulated with LPS (1 ng/ml), whereas their response to higher LPS doses (100 and 1,000 ng/ml) was essentially normal. The importance of the CD14 molecule in the activation of phagocytes by low LPS concentrations was confirmed by the inhibitory effect of an anti-CD14 antibody both in healthy volunteers and in PNH patients. Since these patients produce the soluble form of the CD14 molecule, these data suggest that soluble CD14 could play a role in phagocyte responses to LPS. We conclude that, in whole blood, phagocytes from PNH patients show impaired responsiveness to LPS and this phenomenon is most probably related to their defect in expression of membrane CD14. PMID:7691746

Duchow, J; Marchant, A; Crusiaux, A; Husson, C; Alonso-Vega, C; De Groote, D; Neve, P; Goldman, M



Personal endotoxin exposure in a panel study of school children with asthma  

PubMed Central

Background Endotoxin exposure has been associated with asthma exacerbations and increased asthma prevalence. However, there is little data regarding personal exposure to endotoxin in children at risk, or the relation of personal endotoxin exposure to residential or ambient airborne endotoxin. The relation between personal endotoxin and personal air pollution exposures is also unknown. Methods We characterized personal endotoxin exposures in 45 school children with asthma ages 9-18 years using 376 repeated measurements from a PM2.5 active personal exposure monitor. We also assayed endotoxin in PM2.5 samples collected from ambient regional sites (N = 97 days) and from a subset of 12 indoor and outdoor subject home sites (N = 109 and 111 days, respectively) in Riverside and Whittier, California. Endotoxin was measured using the Limulus Amoebocyte Lysate kinetic chromogenic assay. At the same time, we measured personal, home and ambient exposure to PM2.5 mass, elemental carbon (EC), and organic carbon (OC). To assess exposure relations we used both rank correlations and mixed linear regression models, adjusted for personal temperature and relative humidity. Results We found small positive correlations of personal endotoxin with personal PM2.5 EC and OC, but not personal PM2.5 mass or stationary site air pollutant measurements. Outdoor home, indoor home and ambient endotoxin were moderately to strongly correlated with each other. However, in mixed models, personal endotoxin was not associated with indoor home or outdoor home endotoxin, but was associated with ambient endotoxin. Dog and cat ownership were significantly associated with increased personal but not indoor endotoxin. Conclusions Daily fixed site measurements of endotoxin in the home environment may not predict daily personal exposure, although a larger sample size may be needed to assess this. This conclusion is relevant to short-term exposures involved in the acute exacerbation of asthma. PMID:21810249



Effect of time post mortem on the concentration of endotoxin in rat organs: implications for sudden infant death syndrome (SIDS)  

Microsoft Academic Search

The aim of the study was to test the following hypotheses: (i) that endotoxin injected 40 min prior to death can be detected in rat organs post mortem and (ii) that endotoxin levels do not change with increasing time post mortem. Rats were injected with or without endotoxin in buffered saline, 40 min prior to being killed. Endotoxin levels in

Nicola M. Sayers; Barbara A. Crawley; Kevin Humphries; David B. Drucker; Beryl A. Oppenheim; Linda P. Hunt; James A. Morris; David R. Telford



Endotoxin release in cardiac surgery with cardiopulmonary bypass: pathophysiology and possible therapeutic strategies. An update.  


Cardiac surgery with cardiopulmonary bypass provokes a systemic inflammatory response syndrome caused by the surgical trauma itself, blood contact with the non-physiological surfaces of the extracorporeal circuit, endotoxemia, and ischemia. The role of endotoxin in the inflammatory response syndrome has been well investigated. In this report, we reviewed recent advances in the understanding of the pathophysiology of the endotoxin release during cardiopulmonary bypass and the possible therapeutic strategies aimed to reduce the endotoxin release or to counteract the inflammatory effects of endotoxin. Although many different strategies to detoxify endotoxins were evaluated, none of them were able to show statistically significant differences in clinical outcome. PMID:20663682

Kats, Suzanne; Schönberger, Jacques P A M; Brands, Ruud; Seinen, Willem; van Oeveren, Wim



Innate immune activation in neonatal tracheal aspirates suggests endotoxin-driven inflammation  

PubMed Central

Background: Tracheal aspirates (TAs) from critically ill neonates accumulate bacterial endotoxin and demonstrate mobilization of endotoxin-binding proteins, but the potential bioactivity of endotoxin in TAs is unknown. We characterized innate immune activation in TAs of mechanically ventilated neonates. Methods: Innate immune activation in TAs of mechanically ventilated neonates was characterized using a targeted 84-gene quantitative real-time (qRT) PCR array. Protein expression of cytokines was confirmed by multiplex assay. Expression and localization of the endotoxin-inducible antimicrobial protein Calgranulin C (S100A12) was assessed by flow cytometry. Endotoxin levels were measured in TA supernatants using the Limulus amoebocyte lysate assay. Results: Analyses by qRT-PCR demonstrated expression of pattern recognition receptors, Toll-like receptor-nuclear factor ?B and inflammasome pathways, cytokines/chemokines and their receptors, and anti-infective proteins in TA cells. Endotoxin positivity increased with postnatal age. As compared with endotoxin-negative TAs, endotoxin-positive TAs demonstrated significantly greater tumor necrosis factor (TNF), interleukin (IL)-6, IL-10, and serpin peptidase inhibitor, clade E, member 1 (SERPINE1) mRNA, and IL-10, TNF, and IL-1? protein. Expression of S100A12 protein was localized to TA neutrophils. Conclusion: Correlation of endotoxin with TA inflammatory responses suggests endotoxin bioactivity and the possibility that endotoxin antagonists could mitigate pulmonary inflammation and its sequelae in this vulnerable population. PMID:22580716

Nathe, Katheryn E.; Mancuso, Christy J.; Parad, Richard; Van Marter, Linda J.; Martin, Camilia R.; Stoler-Barak, Liat; Philbin, Victoria J.; Phillips, Michele F.; Palmer, Christine D.; Levy, Ofer



A Cytophaga species endotoxin as a putative agent of occupation-related lung disease.  


A previous study suggested that a biologically active bacterial endotoxin was a putative agent of lung disease in a textile-producing facility. The endotoxin was isolated from the biomass growing in a chilled-water spray air humidification system. The bacterial flora of the air humidification system were isolated and taxonomically identified to the genus level. By using indirect immunofluorescence assays, a serologically reactive Cytophaga species was identified. A serologically reactive, biologically active (Limulus assay) endotoxin was purified from phenol extracts of the Cytophaga species. The endotoxin contained sugars, hexosamines, and lipids identical to those found in the humidifier biomass endotoxin. All subjects with biopsy-proven and suspected lung disease had antibodies directed toward the purified Cytophaga endotoxin. The data suggest that the Cytophaga endotoxin is the putative agent of lung disease in the textile facility. PMID:6360896

Flaherty, D K; Deck, F H; Hood, M A; Liebert, C; Singleton, F; Winzenburger, P; Bishop, K; Smith, L R; Bynum, L M; Witmer, W B



Alveolar NF-?B signaling regulates endotoxin-induced lung inflammation.  


ABSTRACT Purpose/aim. The alveolar epithelium participates in host defense through inflammatory pathways that activate NF-?B. Lung infections involving endotoxins trigger acute respiratory distress syndrome (ARDS) in adult and pediatric patients. The purpose of this study was to test the hypothesis that overexpression of NF-?B would worsen and conditional deletion of NF-?B signaling would improve endotoxin-induced lung inflammation using transgenic mouse models. Materials and Methods. Two previously described transgenic mouse models were used in which overexpression of the RelA/p65 subunit of NF-?B was targeted to the lung epithelium using an SPC promoter (SPC-RelA) and conditional deletion of the IKK? molecule involved in NF-?B signaling was targeted to the lung epithelium using Nkx2.1(Cre) (Nkx2.1(Cre);IKK?(F/F)). Adult transgenic and control mice were injected with intratracheal lipopolysaccharide (LPS) or saline followed by lung harvest at 48 h. Collected tissue included whole lungs from transgenic and control mice which was processed for analysis of BAL, lung histology, chemokine expression, and markers of cell apoptosis as well as collection of freshly isolated AECII cells from wild type mice for additional chemokine and apoptotic marker analysis. Results. SPC-RelA mice showed significant increases in lung inflammation and injury following LPS injection with increased neutrophil recruitment as compared to wild type and saline treated controls. In contrast, Nkx2.1(Cre); IKK?(F/F) mice showed markedly decreased lung inflammation and injury with decreased neutrophil recruitment as compared to controls. In both models, lung inflammation was associated with increased cell apoptosis and these findings were confirmed in freshly isolated AECII cells in wild type mice following LPS injection. Conclusions. Overexpression of NF-?B targeted to the lung epithelium worsened lung inflammation and injury in response to LPS exposure while conditional deletion of NF-?B signaling reduced lung inflammation. Lung inflammation and injury were associated with increased cell apoptosis. PMID:25517107

Lopez, Benjamin; Maisonet, Tiffany M; Londhe, Vedang A



Integrating Murine Gene Expression Studies to Understand Obstructive Lung Disease Due to Chronic Inhaled Endotoxin  

PubMed Central

Rationale Endotoxin is a near ubiquitous environmental exposure that that has been associated with both asthma and chronic obstructive pulmonary disease (COPD). These obstructive lung diseases have a complex pathophysiology, making them difficult to study comprehensively in the context of endotoxin. Genome-wide gene expression studies have been used to identify a molecular snapshot of the response to environmental exposures. Identification of differentially expressed genes shared across all published murine models of chronic inhaled endotoxin will provide insight into the biology underlying endotoxin-associated lung disease. Methods We identified three published murine models with gene expression profiling after repeated low-dose inhaled endotoxin. All array data from these experiments were re-analyzed, annotated consistently, and tested for shared genes found to be differentially expressed. Additional functional comparison was conducted by testing for significant enrichment of differentially expressed genes in known pathways. The importance of this gene signature in smoking-related lung disease was assessed using hierarchical clustering in an independent experiment where mice were exposed to endotoxin, smoke, and endotoxin plus smoke. Results A 101-gene signature was detected in three murine models, more than expected by chance. The three model systems exhibit additional similarity beyond shared genes when compared at the pathway level, with increasing enrichment of inflammatory pathways associated with longer duration of endotoxin exposure. Genes and pathways important in both asthma and COPD were shared across all endotoxin models. Mice exposed to endotoxin, smoke, and smoke plus endotoxin were accurately classified with the endotoxin gene signature. Conclusions Despite the differences in laboratory, duration of exposure, and strain of mouse used in three experimental models of chronic inhaled endotoxin, surprising similarities in gene expression were observed. The endotoxin component of tobacco smoke may play an important role in disease development. PMID:23675439

Lai, Peggy S.; Hofmann, Oliver; Baron, Rebecca M.; Cernadas, Manuela; Meng, Quanxin Ryan; Bresler, Herbert S.; Brass, David M.; Yang, Ivana V.; Schwartz, David A.; Christiani, David C.; Hide, Winston



Endotoxin-Induced Endothelial Fibrosis Is Dependent on Expression of Transforming Growth Factors ?1 and ?2  

PubMed Central

During endotoxemia-induced inflammatory disease, bacterial endotoxins circulate in the bloodstream and interact with endothelial cells (ECs), inducing dysfunction of the ECs. We previously reported that endotoxins induce the conversion of ECs into activated fibroblasts. Through endotoxin-induced endothelial fibrosis, ECs change their morphology and their protein expression pattern, thereby suppressing endothelial markers and upregulating fibrotic proteins. The most commonly used fibrotic inducers are transforming growth factor ?1 (TGF-?1) and TGF-?2. However, whether TGF-?1 and TGF-?2 participate in endotoxin-induced endothelial fibrosis remains unknown. We have shown that the endotoxin-induced endothelial fibrosis process is dependent on the TGF-? receptor, ALK5, and the activation of Smad3, a protein that is activated by ALK5 activation, thus suggesting that endotoxin elicits TGF-? production to mediate endotoxin-induced endothelial fibrosis. Therefore, we investigated the dependence of endotoxin-induced endothelial fibrosis on the expression of TGF-?1 and TGF-?2. Endotoxin-treated ECs induced the expression and secretion of TGF-?1 and TGF-?2. TGF-?1 and TGF-?2 downregulation inhibited the endotoxin-induced changes in the endothelial marker VE-cadherin and in the fibrotic proteins ?-SMA and fibronectin. Thus, endotoxin induces the production of TGF-?1 and TGF-?2 as a mechanism to promote endotoxin-induced endothelial fibrosis. To the best of our knowledge, this is the first report showing that endotoxin induces endothelial fibrosis via TGF-? secretion, which represents an emerging source of vascular dysfunction. These findings contribute to understanding the molecular mechanism of endotoxin-induced endothelial fibrosis, which could be useful in the treatment of inflammatory diseases. PMID:24935972

Echeverría, César; Montorfano, Ignacio; Tapia, Pablo; Riedel, Claudia; Cabello-Verrugio, Claudio



E. coli  

NSDL National Science Digital Library

E. coli (Escherichia coli) cannot be seen with the naked eye and must be viewed under a microscope. Most strains are harmless and live in the human gut, but some strains can cause severe food poisoning.

Eric Erbe (USDA; ARS-Beltsville Electron Microscopy Unit)



E. Coli  


... JavaScript on. Read more information on enabling JavaScript. E. coli Skip Content Marketing Share this: Main Content Area Overview Hundreds of E. coli strains are harmless, including those that thrive in ...


Preventive and therapeutic anti-inflammatory effects of systemic and topical thalidomide on endotoxin-induced uveitis in rats.  


The present study examined the outcomes of systemic or topical treatment with thalidomide, a compound that possesses anti-inflammatory, immunomodulatory and anti-angiogenic properties, in rats subjected to endotoxin-induced uveitis (EIU). The effects of thalidomide were evaluated on endotoxin-induced leucocyte and protein infiltration and also on the production of interleukin (IL)-1beta and tumour necrosis factor (TNF)-alpha in rat aqueous humour (AqH). Moreover, the actions of thalidomide were assessed on the cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) protein expression in retinal tissue. EIU was produced by a hindpaw injection of lipopolysaccharide (LPS), in male Wistar rats. Thalidomide (5, 25 and 50 mg/kg) was administered orally 1 h before LPS injection. In another set of experiments, to evaluate the therapeutic efficacy, 5% thalidomide was applied topically to both eyes at 6, 12 and 18 h after LPS administration. The oral pre-treatment with thalidomide decreased, in a dose-dependent manner, the number of inflammatory cells, the protein concentration, and the levels of IL-1beta and TNF-alpha in the AqH. Similar results were found in the AqH of rats that received a topical application of thalidomide. Furthermore, oral (50 mg/kg) and local (5%) thalidomide treatment also reduced expression of the pro-inflammatory proteins COX-2 and iNOS in the posterior segment of the eye. Thalidomide exhibited marked preventive and curative ocular effects in EIU in rats, a property that might be associated with its ability to inhibit the production of inflammatory cytokines and the expression of COX-2 and iNOS. This assembly of data provides additional molecular and functional insights into beneficial effects of thalidomide as an agent for the management of ocular inflammation. PMID:17223105

Rodrigues, Gustavo Büchele; Passos, Giselle Fazzioni; Di Giunta, Gabriella; Figueiredo, Cláudia Pinto; Rodrigues, Eduardo Büchele; Grumman, Astor; Medeiros, Rodrigo; Calixto, Joăo B



E. Coli  


... Digestive System How the Body Works Main Page E. Coli KidsHealth > Kids > Staying Healthy > Fabulous Food > E. Coli Print A A A Text Size What's in ... Do? What Can Kids Do? What Is It? E. coli is a common type of bacteria that can ...


Research paper Simultaneous metal chelate affinity purification and endotoxin  

E-print Network

of antibody fragments of over 90%. Non-ionic detergent treatment did not compromise integrity-ionic detergent takes advantage of the hydrophobic properties of endotoxin trapping them in the detergent phase, whereas the hydrophobic proteins remain in the aqueous phase (Aida and Pabst, 1990). It is, however, time

Lebendiker, Mario


EEnnddooTTrraapp 55//11 Endotoxin removal system  

E-print Network

Trap gel slurry, fill the slurry in an appropriately sized column and allow gel to settle for 30 minutes at least 3 times without loss of endotoxin removal efficiency! Kit Components Prepacked EndoTrap columns 5 Storage EndoTrap is supplied as prepacked columns (EndoTrap 5/1, Cat.Nr.: 311063, 1 ml column material

Lebendiker, Mario


Alteco endotoxin hemoadsorption in Gram-negative septic shock patients  

PubMed Central

Background and Aims: Severe sepsis and septic shock are common causes of mortality and morbidity in an intensive care unit setting. Endotoxin, derived from the outer membranes of Gram-negative bacteria, is considered a major factor in the pathogenesis of sepsis. This study investigated the effect of Alteco endotoxin hemoadsorption device on Gram-negative septic shock patients. Materials and Methods: An open, controlled, prospective, randomized, single-center trial was conducted between February 2010 and June 2012. Patients with septic shock due to intra-abdominal sepsis were randomized to either conventional therapy (n = 8) or conventional therapy plus two 2-hourly sessions of Alteco endotoxin hemoadsorption (n = 7). Primary endpoint was the Sequential Organ Failure Assessment (SOFA) score changes from 0 to 72 h. Secondary end points included vasopressor requirement, PaO2/FiO2 ratio (PFR), length of stay (LOS), and 28-day mortality. Results: This study was terminated early as interim analysis showed a low probability of significant findings. No significant difference was noted between the two groups with respect to change in SOFA score, vasopressor score, PFR, LOS, and 28-day mortality. Side-effect was minimal. Conclusions: We could not identify any clinical benefit on the addition of Alteco endotoxin hemoadsorption to conventional therapy in patients who suffered from intra-abdominal sepsis with shock. The side effect profile of this novel device was acceptable. PMID:25538412

Shum, Hoi Ping; Leung, Yuk Wah; Lam, Sin Man; Chan, King Chung; Yan, Wing Wa



Original article The effect of endotoxin-contaminated medium  

E-print Network

Original article The effect of endotoxin-contaminated medium on in vitro fertilization and development of bovine oocytes matured in vitro V Madison T Greve1 B Avery T Wamberg V Mortensen M Balle R preparation and co-culture of bovine sperm and oocytes affects in vitro penetration and embryonic development

Paris-Sud XI, Université de


Streptomycetes in house dust: associations with housing characteristics and endotoxin  

EPA Science Inventory

In addition to mold, indoor bioaerosols also contain bacterial components that may have implications for human health. Endotoxin is a cell wall component in Gram-negative bacteria present at varying levels indoors that has been found to have respiratory health implications. Stre...


Personal Endotoxin Exposure in School Children with Asthma  

E-print Network

C) Relative Humidity (%) Indoor Air Pollution and Weather PMindoor-outdoor home and ambient endotoxin and air pollutionsIndoor Outdoor Ambient PM 2.5 (?g/m 3 ) EC (?g/m 3 ) OC (?g/m 3 ) Personal Air Pollution

Delfino, Ralph J; Staimer, Norbert; Tjoa, Thomas



Reduction of endotoxin attenuates liver fibrosis through suppression of hepatic stellate cell activation and remission of intestinal permeability in a rat non-alcoholic steatohepatitis model  

PubMed Central

Previous clinical studies have demonstrated that endotoxin/toll-like receptor 4 (TLR4) signaling is critical in the inflammatory pathways associated with non-alcoholic steatohepatitis (NASH). In human and animal studies, NASH was associated with portal lipopolysaccharide (LPS) and the plasma LPS level was hypothesized to be associated with small intestinal bacterial overgrowth, change in composition of the microbiota and increased intestinal permeability. The aim of the present study was to investigate the roles of endogenous endotoxin and TLR4 in the pathogenesis of NASH. The effects of antibiotics were assessed in vivo using a choline deficiency amino acid (CDAA)-induced experimental liver fibrosis model. Antibiotics, including polymyxins and neomycins, were orally administered in drinking water. Antibiotics attenuated hepatic stellate cell (HSC) activation and liver fibrosis via TGF-? and collagen in an experimental hepatic fibrosis model. The mechanism by which antibiotics attenuated LPS-TLR4 signaling and liver fibrosis was assessed. Notably, TLR4 mRNA level in the liver was elevated in the CDAA group and the CDAA-induced increase was significantly reduced by antibiotics. However, no significant differences were observed in the intestine among all groups. Elevated mRNA levels of LPS binding protein, which was correlated with serum endotoxin levels, were recognized in the CDAA group and the CDAA-induced increase was significantly reduced by antibiotics. The intestinal permeability of the CDAA group was increased compared with the choline-supplemented amino acid group. The tight junction protein (TJP) in the intestine, determined by immunohistochemical analysis was inversely associated with intestinal permeability. Antibiotics improved the intestinal permeability and enhanced TJP expression. Inhibition of LPS-TLR4 signaling with antibiotics attenuated liver fibrosis development associated with NASH via the inhibition of HSC activation. These results indicated that reduction of LPS and restoration of intestinal TJP may be a novel therapeutic strategy for treatment of liver fibrosis development in NASH. PMID:25421042




Effect of the Toll-Like Receptor 4 Antagonist Eritoran on Retinochoroidal Inflammatory Damage in a Rat Model of Endotoxin-Induced Inflammation  

PubMed Central

Purpose. We investigated the effect of eritoran, a Toll-like receptor 4 antagonist, on retinochoroidal inflammatory damage in an endotoxin-induced inflammatory rat model. Methods. Endotoxin-induced inflammatory model was obtained by intraperitoneal injection of 1.5?mg/kg lipopolysaccharide (LPS). Group 1 had control rats; in groups 2-3 LPS and 0.5?mg/kg sterile saline were injected; and in groups 4-5 LPS and 0.5?mg/kg eritoran were injected. Blood samples were taken and eyes were enucleated after 12 hours (h) (groups 2 and 4) or 24 hours (Groups 3 and 5). Tumor necrosis factor-? (TNF-?) and malondialdehyde (MDA) levels in the serum and retinochoroidal tissue and nuclear factor kappa-B (NF?B) levels in retinochoroidal tissue were determined. Histopathological examination was performed and retinochoroidal changes were scored. Results. Eritoran treatment resulted in lower levels of TNF-?, MDA, and NF?B after 12?h which became significant after 24 h. Serum TNF-? and retinochoroidal tissue NF?B levels were similar to control animals at the 24th?h of the study. Eritoran significantly reversed histopathological damage after 24 h. Conclusions. Eritoran treatment resulted in less inflammatory damage in terms of serum and retinochoroidal tissue parameters. PMID:25165412

Karaca, Emine Esra; Korkmaz, ?afak; Yüksel, Osman; Gülbahar, Özlem; Alper, Murat; Ercan, Sevim; Or, Meral



A morphological study of the action of equine anti-lipopolysaccharide plasma on gram-negative bacteria  

Microsoft Academic Search

Summary. Three strains of gram-negative bacteria-one each of Escherichia coli, Klebsiellapneumoniae and Enterobacter sp.-were treated with anti-lipopolysaccharide hyperimmune equine plasma (anti-LPS) or non-immune control plasma and examined by scanning electronmicroscopy. Within a few minutes of treatment with anti-LPS, bacteria were agglutinated. Evidence of cell membrane destruction was observed shortly thereafter and total cell disintegration and disruption occurred within 1-2 h.

S. L. Gaffin; M. T. Wells



Lactoferrin Inhibits the Lipopolysaccharide-Induced Expression and Proteoglycan-Binding Ability of Interleukin8 in Human Endothelial Cells  

Microsoft Academic Search

Interleukin-8 (IL-8), a C-X-C chemokine bound to endothelium proteoglycans, initiates the activation and selective recruitment of leukocytes at inflammatory foci. We demonstrate that human lactoferrin, an antimi- crobial lipopolysaccharide (LPS)-binding protein, decreases both IL-8 mRNA and protein expression induced by the complex Escherichia coli 055:B5 LPS\\/sCD14 in human umbilical vein endothelial cells. The use of recombinant lactoferrins mutated in the

Elisabeth Elass; Maryse Masson; Joël Mazurier; Dominique Legrand



Lipopolysaccharide Does Not Alter Small Airway Reactivity in Mouse Lung Slices  

PubMed Central

The bacterial endotoxin, lipopolysaccharide (LPS) has been associated with occupational airway diseases with asthma-like symptoms and in acute exacerbations of COPD. The direct and indirect effects of LPS on small airway reactivity have not been fully elucidated. We tested the hypothesis that both in vitro and in vivo LPS treatment would increase contraction and impair relaxation of mouse small airways. Lung slices were prepared from naďve Balb/C mice and cultured in the absence or presence of LPS (10 ?g/ml) for up to 48 h for measurement of TNF? levels in conditioned media. Alternatively, mice were challenged with PBS or LPS in vivo once a day for 4 days for preparation of lung slices or for harvest of lungs for Q-PCR analysis of gene expression of pro-inflammatory cytokines and receptors involved in airway contraction. Reactivity of small airways to contractile agonists, methacholine and serotonin, and bronchodilator agents, salbutamol, isoprenaline and rosiglitazone, were assessed using phase-contrast microscopy. In vitro LPS treatment of slices increased TNF? release 6-fold but did not alter contraction or relaxation to any agonists tested. In vivo LPS treatment increased lung gene expression of TNF?, IL-1? and ryanodine receptor isoform 2 more than 5-fold. However there were no changes in reactivity in lung slices from these mice, even when also incubated with LPS ex vivo. Despite evidence of LPS-induced inflammation, neither airway hyperresponsiveness or impaired dilator reactivity were evident. The increase in ryanodine receptor isoform 2, known to regulate calcium signaling in vascular smooth muscle, warrants investigation. Since LPS failed to elicit changes in small airway reactivity in mouse lung slices following in vitro or in vivo treatment, alternative approaches are required to define the potential contribution of this endotoxin to altered small airway reactivity in human lung diseases. PMID:25822969

Donovan, Chantal; Royce, Simon G.; Vlahos, Ross; Bourke, Jane E.



Protective effects of erythropoietin on endotoxin-related organ injury in rats.  


The protective effect of erythropoietin (EPO) on tissues following ischemia and reperfusion injuries remains poorly understood. We aimed to investigate the effect of EPO in preventing endotoxin-induced organ damage. Rat model of multiple organ failure (MOF) was established by tail vein injection of 10 mg/kg lipopolysaccharide (LPS). Recombinant human EPO treatment (5000 U/kg) was administered by tail vein injection at 30 min after LPS challenge. Twenty-four h after EPO treatment, changes in serum enzyme levels, including aspartate aminotransferase (AST), alanine transaminase (ALT), blood urea nitrogen (BUN) and creatinine (Cr), were evaluated by biochemical analysis. Serum levels of tumor necrosis factor-? (TNF-?) were determined by using immunoradiometric assay. Histological examination of tissue sections was carried out by hematoxylin and eosin staining, while ultrastructure evaluation of organ tissues was assessed by transmission electron microscopy. Protein expression levels were detected by using Western blotting. EPO treatment showed a modest effect in preventing LPS-induced elevation of AST, ALT, BUN, Cr, and TNF-? levels, and in protecting against LPS-induced tissue degeneration and injured ultrastructure in the lung, liver, and kidney. Moreover, LPS promoted phosphorylation of alanine aminotransferase (AKT) and increased nuclear factor-?B (NF-?B) activation in the lung, liver, and kidney (P<0.05 vs. control). However, EPO treatment significantly decreased the LPS-induced pAKT up-regulation in these tissues (P<0.05 vs. LPS treatment alone). The present study demonstrates that EPO may play a protective role against LPS-induced MOF by reducing the inflammatory response and tissue degeneration, possibly via the phosphatidylinositol 3-kinase/AKT and NF-?B signaling pathways. PMID:24142720

Li, Xiu-jiang; Zhang, Guo-xing; Sun, Ni; Sun, Yu; Yang, Li-zhi; Du, Yu-jun



Alkaline phosphatases contribute to uterine receptivity, implantation, decidualization and defense against bacterial endotoxin in hamsters  

PubMed Central

Alkaline phosphatase (AP) activity has been demonstrated in the uterus of several species, but its importance in the uterus, in general and during pregnancy, is yet to be revealed. In this study, we focused on identifying AP isozyme types, and their hormonal regulation, cell-type and event-specific expression and possible functions in the hamster uterus during the cycle and early pregnancy. Our RT-PCR and in situ hybridization studies demonstrated that among the known Akp2, Akp3, Akp5 and Akp6 murine AP isozyme genes, hamster uteri express only Akp2 and Akp6; and both genes are co-expressed in luminal epithelial cells. Studies in cyclic and ovariectomized hamsters established that while progesterone is the major uterine Akp2 inducer, both progesterone and estrogen are strong Akp6 regulators. Studies in preimplantation uteri showed induction of both genes and the activity of their encoded isozymes in luminal epithelial cells during uterine receptivity. However, at the beginning of implantation, Akp2 showed reduced expression in luminal epithelial cells surrounding the implanted embryo. In contrast, expression of Akp6 and its isozyme was maintained in luminal epithelial cells adjacent to, but not away from, the implanted embryo. Following implantation, stromal transformation to decidua was associated with induced expressions of only Akp2 and its isozyme. We next demonstrated that uterine APs dephosphorylate and detoxify endotoxin lipopolysaccharide at their sites of production and activity. Taken together, our findings suggest that uterine APs contribute to uterine receptivity, implantation, and decidualization in addition to their role in protection of the uterus and pregnancy against bacterial infection. PMID:23929901

Lei, Wei; Nguyen, Heidi; Brown, Naoko; Ni, Hua; Kiffer-Moreira, Tina; Reese, Jeff; Millán, José Luis; Paria, Bibhash C.



Green Tea Extract Treatment Alleviates Ocular Inflammation in a Rat Model of Endotoxin-Induced Uveitis  

PubMed Central

Green tea extract (GTE) ingested by rats exerted anti-oxidative activities in various ocular tissues as shown in our previous studies. The present work investigated anti-inflammatory effects of GTE on endotoxin-induced uveitis (EIU). EIU was generated in adult rats by a footpad injection of 1 mg/kg lipopolysaccharide (LPS). Oral administration of GTE (550 mg/kg) was given one, two or four times after LPS injection. Twenty-four hours later, LPS produced severe hyperemia and edema in the iris. Immunocytochemical examinations showed an accumulation of infiltrating cells in the aqueous humor that were immunopositive for cluster of differentiation 43 (CD43) and CD68, markers for leucocytes and macrophages, respectively. Analyses of the aqueous humor showed an increase in pro-inflammatory mediators including tumor necrosis factor-alpha (TNF-?), interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1). GTE treatments improved the clinical manifestations and reduced infiltrating cells and protein exudation in the aqueous humor, which were not observed under half dose of GTE (275 mg/kg). The number of CD68 positive macrophages residing in the iris and ciliary was also reduced. GTE suppressed production of TNF-?, IL-6 and MCP-1 in the aqueous humor, which was associated with a down-regulation of LPS receptor complex subunits, Toll-like receptor 4 (TLR-4) and CD14, and suppression of nuclear factor-kappa Bp65 (NF-?Bp65) in the iris and ciliary body. Our findings show that GTE is a potent anti-inflammatory agent against the inflammation of EIU, and suggest a potential use in treatment of acute uveitis. PMID:25093862

Qin, Yong Jie; Chu, Kai On; Yip, Yolanda Wong Ying; Li, Wai Ying; Yang, Ya Ping; Chan, Kwok Ping; Ren, Jia Lin



Corticotropin releasing factor in the rat colon: expression, localization and upregulation by endotoxin  

PubMed Central

Little is known about CRF expression and regulation in the rat colon compared to the brain. We investigated CRF gene expression, cellular location, and regulation by endotoxin and corticosterone in the male rat colon at 6 h after intraperitoneal (ip) injection. CRF mRNA level, detected by reverse transcription polymerase chain reaction (RT-PCR) was 2.3-fold higher in the distal than proximal colon and 4.4-fold higher in the proximal colonic submucosa plus muscle layers than in mucosa. CRF immunoreactivity was located in the epithelia, lamina propria and crypts, and co-localized with tryptophan hydroxylase, a marker for enterochromaffin (EC) cells, and in enteric neurons. Lipopolysaccharide (LPS, 100 ?g/kg, ip) increased defecation by 2.9-fold and upregulated CRF mRNA by 3.5-fold in the proximal and 2.1-fold in the distal colon while there was no change induced by corticosterone as monitored by quantitative PCR. LPS-induced increased CRF mRNA expression occurred in the submucosa plus muscle layers (2.5-fold) and the mucosa of proximal colon (1.9-fold). LPS increased significantly CRF immunoreactivity in the submucosal and myenteric plexuses of proximal and distal colon compared to saline groups. These results indicate that in rats, CRF is expressed in both proximal and distal colon and more prominently in enteric neurons of the submucosa plus muscle layers and subject to upregulation at the gene and protein levels by LPS through corticosteroid independent pathways. These data suggests that colonic CRF may be part of the local effector limb of the CRF1 receptor mediated colonic alterations induced by acute stress. PMID:19944726

Yuan, P.-Q.; Wu, S. V.; Wang, L.; Taché, Y.



A critical role for monocytes and CD14 in endotoxin-induced endothelial cell activation  

PubMed Central

Vascular endothelium activated by endotoxin (lipopolysaccharide [LPS]) and cytokines plays an important role in organ inflammation and blood leukocyte recruitment observed during sepsis. Endothelial cells can be activated by LPS directly, after its interaction with LPS-binding protein and soluble CD14 in plasma. LPS-LPS-binding protein complexes in blood also interact with monocytes and neutrophils bearing glycosyl- phosphatidylinositol (GPI) anchored membrane CD14 (mCD14), promoting the release of cytokines such as tumor necrosis factor and interleukin 1 (IL-1). These molecules, in turn, have the capacity to activate endothelial cells providing an indirect pathway for LPS-dependent endothelial cell activation. In this work, we address the relative importance of the direct and the indirect pathway of in vitro LPS- induced human umbilical vein endothelial cell (HUVEC) activation. Substituting whole blood for plasma resulted in a 1,000-fold enhancement of HUVEC sensitivity to LPS. Both blood- and plasma- dependent enhanced activation of HUVEC were blocked with an anti-CD14 monoclonal antibody. Blood from patients with paroxysmal nocturnal hemoglobinuria, whose cells lack mCD14 and other GPI anchored proteins, was unable to enhance LPS activation of HUVEC above the level observed with plasma alone. IL-10, an inhibitor of monocyte release of cytokines, decreased the blood-dependent enhancement of HUVEC activation by LPS. Blood adapted to small doses of LPS was also less efficient than nonadapted blood in producing this enhancement. Addition of purified mononuclear cells to HUVEC or the transfer of plasma from whole blood incubated with LPS to HUVEC, duplicated the enhancement effect observed when whole blood was incubated with HUVEC. Taken together, these data suggest that the indirect pathway of LPS activation of endothelial cell is mediated by monocytes and mCD14 through the secretion of a soluble mediator(s). The indirect pathway is far more efficient than the direct, plasma-dependent pathway. PMID:7504060



Docosahexaenoic acid prevents lipopolysaccharide-induced cytokine production in microglial cells by inhibiting lipopolysaccharide receptor presentation but not its membrane subdomain localization.  


Recognition of lipopolysaccharide (LPS), the endotoxin of gram-negative bacteria, by microglia occurs through its binding to specific receptors, cluster of differentiation 14 and toll-like receptor-4. LPS binding to these receptors triggers the synthesis of proinflammatory cytokines that coordinate the brain innate immune response to protect the CNS of the infection. Docosahexaenoic acid (DHA), a n-3 polyunsaturated fatty acid highly incorporated in the brain, is a potent immunomodulator. In this study, we investigated whether DHA modulates LPS receptor localization and, as a consequence, LPS-induced signaling pathway and proinflammatory cytokine production. We demonstrated that DHA, when added exogenously, is specifically enriched in membrane phospholipids, but not in raft lipids of microglial cells. DHA incorporation in membrane impaired surface presentation of LPS receptors cluster of differentiation 14 and toll-like receptor-4, but not their membrane subdomain localization. LPS-induced nuclear factor kappa B activation was inhibited by DHA, hence, LPS-induced proinflammatory cytokine synthesis of interleukin-1beta and tumor necrosis factor alpha was strongly attenuated. We suggest that DHA is highly anti-inflammatory by targeting LPS receptor surface location, therefore reducing LPS action on microglia. This effect represents a new insight by which DHA modulates in the brain the expression of proinflammatory cytokines in response to bacterial product. PMID:18021297

De Smedt-Peyrusse, Véronique; Sargueil, Françoise; Moranis, Aurélie; Harizi, Hedi; Mongrand, Sébastien; Layé, Sophie



Use of indium-111 oxine to study pulmonary and hepatic leukocyte sequestration in endotoxin shock and effects of the beta-2 receptor agonist terbutaline  

SciTech Connect

The dynamic behavior of indium-111 oxine-labeled leukocytes was simultaneously recorded in multiple organs during endotoxin shock in sheep. Also, the effects of the beta-2 receptor agonist terbutaline were studied. An experimental protocol was designed to mimic a clinical condition in an intensive care setting as far as possible. The animals were ventilated with 50% oxygen to avoid hypoxemia and were given large amounts of intravenous fluids to reduce adverse effects of hypovolemia. A moderate dose of E. coli endotoxin (10 micrograms/kg bwt) was given by intravenous infusion to 14 adult sheep, seven of them receiving continuous intravenous infusion of terbutaline (20 micrograms/kg/hr) during 4 hr, starting 30 min after endotoxin, when signs of lung injury had developed. The other seven acted as controls. A marked pulmonary and hepatic leukocyte sequestration together with a sharp drop in leukocyte counts in peripheral blood occurred within minutes after start of the endotoxin infusion in both groups. However, no changes were observed in the kidneys or the gut. After 60 min and until the end of the experiment, there was a significantly lower activity in the lungs and in the liver of the animals treated with terbutaline than in the controls (P less than .01). Furthermore, less marked hemodynamic and respiratory alterations occurred in the terbutaline group compared with the controls. This study confirms the results of other investigators showing that significant leukocyte sequestration occurs in the lungs during endotoxemia, but it also demonstrates that leukocytes sequestrate in the liver, although slightly less than in the lungs.

Sigurdsson, G.H.; Christenson, J.T.; al-Mousawi, M.; Owunwanne, A. (Kuwait Univ., Safat (Kuwait))



Pulmonary capillary wedge pressure estimates of left ventricular preload are inaccurate in endotoxin shock: contribution of Starling resistor forces to septic pulmonary hypertension.  


We tested the hypothesis that Starling resistor forces play a significant role in the increase in pulmonary vascular resistance during endotoxin shock. Anesthetized pigs (n = 9) were given Escherichia coli endotoxin (ETX; .5 mg/kg intravenously over 30 min). Mean pulmonary arterial pressure (MPAP) and pulmonary capillary wedge pressure (PCWP) were recorded through a Swan-Ganz catheter. Pulmonary capillary pressure (Pc) was obtained from the analysis of the transient pulmonary artery pressure decay curve upon balloon inflation. Both proximal (Ra) and distal (Rv) pulmonary vascular resistance were calculated from cardiac output (CO), MPAP, Pc, and PCWP. Left atrial pressure (LAP) was measured directly via a left atrial catheter. Left ventricular end-diastolic wall thickness (LV-EDWT) was monitored by sonomicrometry, and used as an index of left ventricular preload. The results at baseline (t = 0) and t = 60 (30 min after the cessation of endotoxin infusion) were compared with saline control animals (n = 6). Data were analyzed with a two-way ANOVA followed by contrast of residuals (p < or = .05). After endotoxin, arterial blood pressure and CO fell significantly, an effect not seen in control pigs. In the control group neither LAP nor PCWP changed significantly over time, and remained equivalent to each other. In the septic shock group there was no difference between LAP and PCWP at t = 0. However, by t = 60 LAP dropped and PCWP rose significantly. This fall in LAP and increase in PCWP were significantly different from the time-matched control values, and from each other.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7743360

Krahmer, R L; Fang, H K; Vitello, J; Rypins, E B; Law, W R



Quantification of ergosterol and 3-hydroxy fatty acids in settled house dust by gas chromatography-mass spectrometry: comparison with fungal culture and determination of endotoxin by a Limulus amebocyte lysate assay.  

PubMed Central

Ergosterol and 3-hydroxy fatty acids, chemical markers for fungal biomass and the endotoxin of gram-negative bacteria, respectively, may be useful in studies of health effects of organic dusts, including domestic house dust. This paper reports a method for the combined determination of ergosterol and 3-hydroxy fatty acids in a single dust sample and a comparison of these chemical biomarkers determined by gas chromatography-mass spectrometry with results from fungal culture and Limulus assay. Analyses of replicate house dust samples resulted in correlations of 0.91 (ergosterol in six replicates; P < 0.01) and 0.94 (3-hydroxy fatty acids in nine replicates; P < 0.001). The amounts of ergosterol (range, 2 to 16.5 ng/mg of dust) correlated with those of total culturable fungi (range, 6 to 1,400 CFU/mg of dust) in 17 samples, (r = 0.65; P < 0.005). The amounts of endotoxin (range, 11 to 243 endotoxin units/mg of dust) measured with a modified chromogenic Limulus assay correlated with those of lipopolysaccharide (LPS) determined from 3-hydroxy fatty acid analysis of 15 samples. The correlation coefficient depended on the chain lengths of 3-hydroxy acids used to compute the LPS content. The correlation was high (r = 0.88 +/- 0.01; P < 0.001) when fatty acid chains of 10 to 14 carbon atoms were included; the correlation was much lower when hydroxy acids of 16- or 18-carbon chains were included. In conclusion, the results of the described extraction and analysis procedure for ergosterol and 3-hydroxy fatty acids are reproducible, and the results can be correlated with fungal culture and endotoxin activity of organic dust samples. PMID:9212406

Saraf, A; Larsson, L; Burge, H; Milton, D



Effect of activated charcoal on endotoxin adsorption. Part I. An in vitro study.  


An in vitro study by using cross-linked agarose coated activated charcoal (CAAC-II) as adsorbent was conducted. Endotoxin was quantitatively measured by chromogenic method of limulus lysate test. Results of the study demonstrated that endotoxin was fairly efficiently removed by CAAC-II. It may therefore be possible for effective adsorption of endotoxin in vivo studies and warrant further experimental study for CAAC-II hemoperfusion in clinical endotoxemia. PMID:3449139

Du, X N; Niu, Z; Zhou, G Z; Li, Z M



Bioactive and total endotoxins in atmospheric aerosols in the Pearl River Delta region, China  

NASA Astrophysics Data System (ADS)

Endotoxin, a toxic and pyrogenic substance in gram-negative bacteria in atmospheric aerosols was measured over a period of one year at Nansha, Guangzhou and Hong Kong in the Pearl River Delta region, China. Atmospheric aerosols were collected by high-volume samplers. The bioactive endotoxin levels in the samples were determined using the Limulus Amebocyte Lysate (LAL) assay after extraction with pyrogen-free water while the total endotoxin levels were measured by quantifying the biomarker, 3-hydroxy fatty acids (3-OHFAs) with GC-MS. Results showed that there was no significant difference (0.19 < p < 0.81) in the bioactive endotoxin level in PM 10 among sites (average concentrations ranged from 0.34 to 0.39 EU m -3). However, Hong Kong showed a significantly lower ( p < 0.05) total endotoxin level in PM 10 (average of 17.4 ng m -3) compared with Nansha's 29.4 ng m -3 and Guangzhou's 32.7 ng m -3. The bioactive endotoxins were found to be associated with the coarse mode (PM 2.5-10) of the particulates of natural origins while the total endotoxins were associated more with the fine mode (PM 2.5) of the particulates of anthropogenic origins. When normalized with particulate mass, the endotoxin loading is much higher in summer as a result of the increased growth of the bacteria when climatic conditions are favorable. The chemically determined total endotoxins were 3-4 orders of magnitude higher than the bioactive endotoxins quantified using the LAL assay. Correlation analyses between the bioactive endotoxins and 3-OHFAs with different carbon length were analyzed. Results showed that the correlations detected vary among sites and particulate sizes. Although no generalization between the total and bioactive endotoxins can be drawn from the study, the levels reported in this study suggests that the discrepancies between the two measurement approaches, and the bioactive potential of 3-OHFAs with individual carbon chains deserve further investigation.

Cheng, Jessica Y. W.; Hui, Esther L. C.; Lau, Arthur P. S.



Tissue differences in antioxidant enzyme gene expression in response to endotoxin  

Microsoft Academic Search

The effect of endotoxin on antioxidant gene expression and antioxidant enzyme activity in homogenates of the heart, liver, and kidney from Sprague-Dawley rats was compared by quantitation of m-RNA and enzyme activities. Alterations in the message level for Cu-Zn superoxide dismutase (SOD), Mn SOD, and catalase varied with the tissue type, length of exposure to endotoxin, and dose of endotoxin.

Bidyut Ghosh; Coral Dawn Hanevold; Kazushige Dobashi; John Kenneth Orak; Inderjit Singh



Endotoxin levels at Swine farms using different waste treatment and management technologies.  


Concentrated animal feeding operations (CAFOs) are a major source of airborne endotoxins, which are air pollutants that can cause adverse health effects to both on-site farmers and neighbors. Release of airborne endotoxins to the environment can be reduced using proper waste treatment and management technologies. In this study, the levels of endotoxins released from two swine CAFOs using conventional lagoon-sprayfield technology were compared to those of 15 farms using various alternative waste management technologies in North Carolina. Over a 2-year period, 236 endotoxin samples were collected from the 17 farm units and analyzed using the Limulus amebocyte lysate (LAL) test. Concentrations of airborne endotoxins near barn exhaust fans were significantly higher than at the upwind boundary of the farm and at other farm sites. For most of the study sites, mean concentrations of endotoxins at the downwind boundary of the farm were higher than those at the upwind boundary of the farm, indicating the release of endotoxins from swine CAFOs to the neighboring environment. Endotoxin levels were significantly associated with concentrations of airborne bacteria but not fungi. Environmental factors, such as temperature, relative humidity, and wind velocity, affected the levels of airborne endotoxins at the farms. Based on the ratios of airborne endotoxins in downwind and upwind samples from the farm units, at least five different alternative waste management technologies significantly reduced the release of endotoxins from swine CAFOs. These results suggest that swine CAFOs are important sources of airborne endotoxins, the levels of which can be reduced by applying more robust and effective waste management technologies. PMID:20356077

Ko, Gwangpyo; Simmons Iii, Otto D; Likirdopulos, Christina A; Worley-Davis, Lynn; Williams, C M; Sobsey, Mark D



Endotoxin-induced tumor necrosis factor alpha synthesis in murine embryo fibroblasts.  

PubMed Central

Murine embryo fibroblasts (MEF) were found to secrete tumor necrosis factor (TNF) in response to stimulation with endotoxin. Endotoxin-induced TNF production by MEF was inhibited by cycloheximide. However, reversal of the effect of this inhibitor on protein synthesis results in TNF being secreted in amounts equivalent to those produced by endotoxin-induced MEF not treated with cycloheximide. Actinomycin D treatment of MEF blocked the production of endotoxin-induced TNF. Maximal production of TNF required MEF gene transcription during the first 6 h of incubation with endotoxin. To determine whether endotoxin-induced TNF alpha (TNF-alpha) and/or TNF beta were produced by MEF, cDNA was synthesized from the total RNA isolated from endotoxin-induced MEF and amplified by the polymerase chain reaction in the presence of oligonucleotide primers specific for each cytokine. On the basis of the polymerase chain reaction analysis, it was determined that TNF-alpha mRNA levels were increased in endotoxin-induced MEF. Thus, production of TNF-alpha by fibroblasts in response to the endotoxin component of bacterial cell walls is likely to contribute to the expression of TNF-mediated effects occurring in fibroblast-rich tissues infected with gram-negative bacteria. Images PMID:8478050

Havell, E A; Rogerson, B J



Dual labeling of lipopolysaccharides for SPECT-CT imaging and fluorescence microscopy.  


Lipopolysaccharides (LPS) or endotoxins are amphipathic, pro-inflammatory components of the outer membrane of Gram-negative bacteria. In the host, LPS can trigger a systemic inflammatory response syndrome. To bring insight into in vivo tissue distribution and cellular uptake of LPS, dual labeling was performed with a bimodal molecular probe designed for fluorescence and nuclear imaging. LPS were labeled with DOTA-Bodipy-NCS, and pro-inflammatory properties were controlled after each labeling step. LPS were then radiolabeled with (111)In and subsequently injected intravenously into wild-type, C57B16 mice, and their in vivo behavior was followed by single photon emission computed tomography coupled with X-ray computed tomography (SPECT-CT) and fluorescence microscopy. Time course of liver uptake of radiolabeled LPS ((111)In-DOTA-Bodipy-LPS) was visualized over a 24-h period in the whole animal by SPECT-CT. In complementary histological analyses with fluorescent microscopy, the bulk of injected (111)In-DOTA-Bodipy-LPS was found to localize early within the liver. Serum kinetics of unlabeled and DOTA-Bodipy-labeled LPS in mouse plasma were similar as ascertained by direct quantitation of ?-hydroxymyristate, and DOTA-Bodipy-LPS was found to retain the potent, pro-inflammatory property of the unlabeled molecule as assessed by serum cytokine assays. It is concluded that the dual labeling process, involving the formation of covalent bonds between a DOTA-Bodipy-NCS probe and LPS molecules is relevant for imaging and kinetic analysis of LPS biodistribution, both in vivo and ex vivo. Data of the present study come in direct and visual support of a lipopolysaccharide transport through which pro-inflammatory LPS can be transported from the periphery to the liver for detoxification. The (111)In-DOTA-Bodipy-LPS probe arises here as a relevant tool to identify key components of LPS detoxification in vivo. PMID:24328371

Duheron, Vincent; Moreau, Mathieu; Collin, Bertrand; Sali, Wahib; Bernhard, Claire; Goze, Christine; Gautier, Thomas; Pais de Barros, Jean-Paul; Deckert, Valérie; Brunotte, François; Lagrost, Laurent; Denat, Franck



Chemotactic Gradients Predict Neutrophilic Alveolitis in Endotoxin-treated Rats  

Microsoft Academic Search

We hypothesized that the intensity of neutrophilic alveolitis is related to establishing a gradient of neutrophil attractant chemokines across the alveolar-capillary barrier. In these experiments, a posi- tive chemokine gradient toward the alveoli was induced by intratracheal instillation of endotoxin in rats (IT LPS). Alteration of the chemotactic gradient was induced by combining IT LPS (0.1 mg\\/kg) with an intraperitoneal




Gel clot bacterial endotoxin test of FDG: Indian scenario  

PubMed Central

Background: The bacterial endotoxin test (BET) performed using gel clot method is a 60-min test and typically performed after the decay of the 2-(18F) fluoro-2-deoxy-d-glucose (F18-FDG) sample to determine the endotoxin content. The objective of this study protocol was to perform BET testing of F18-FDG by gel clot method. Materials and Methods: Ten random decayed samples of the F18-FDG were subjected to the gel clot BET. The assay was performed with undiluted F18-FDG and at four different maximum valid dilutions of 1:10, 1:100, 1:350 and 1:700 (total number of tests = 100). The sensitivity of the LAL reagent used was 0.125 EU/ml. Endotoxin dilutions were freshly prepared from control standard endotoxin (CSE) stock solution for each F18-FDG batch testing. If the gel had formed and remained intact in the bottom of the reaction tube after an inversion of 180°, the test was considered positive. Any other state of the reaction mixture constituted a negative test. Results: In the undiluted samples, the measured pH (7.05) was well within the acceptable range (i.e. 6.0–8.0) for the gel clot assay. Of the 10 undiluted F18-FDG batches and all the diluted samples, none gelled after 60-min incubation period at 37°C. However, the undiluted F18-FDG did inhibit gel formation at the lysate sensitivity of 0.125 EU/ml. Conclusion: The total volume of FDG produced was 16 ml in the synthesis module. The total F18-FDG preparation at any time did not contain more than 8 EU (0.5 EU/ml × 16 ml). Thus, the product is safe for human administration. PMID:23326067

Sharma, Sarika; Mittal, Bhagwant Rai; Vatsa, Rakhee; Singh, Baljinder



Neuropharmacological agents modifying endotoxin-induced changes in mice1  

PubMed Central

A variety of neuropharmacological agents were tested to elucidate how chlorpromazine influenced an endotoxin-induced reaction. The results obtained, particularly with beta-adrenergic blocking agents, reserpine and fusaric acid, suggested that the primary locus of chlorpromazine's action was mediated by peripheral beta-adrenergic receptor blockade. Such a locus is compatible with the low doses of propranolol which suppress the reaction, and with successful treatment of shock with dopamine. PMID:6112273

Wright, David J M; Weller, Malcolm P I



A 15-week experimental exposure of pigs to airborne dust with added endotoxin in a continuous flow exposure chamber.  

PubMed Central

The purpose of this study was to evaluate the effect of longterm exposure to airborne dust and endotoxin on the respiratory system of pigs. A continuous flow exposure chamber was built for the purpose of exposing pigs to selected airborne contaminants. Pigs (n = 6) were exposed to a combination of a very fine corn/soybean meal (40.6 mg/m3) with added lipopolysaccharide (LPS; 12.4 microg/m3) for 8 h/d over 5 d for 15 wk (75 d of exposure). Control pigs (n = 6) were housed in a room with minimal contamination of these airborne contaminants. Surprisingly, dust in the exposure chamber and the control room was highly contaminated with peptidoglycan. Changes in the lung were monitored by collecting bronchoalveolar lavage (BAL) fluid for cytology at 5 different time points throughout the exposure period. Blood samples were collected at the same time for hematology. A non-specific respiratory inflammatory response was found in exposed and control pigs, as suggested by the increased neutrophils in BAL fluid and the small inflammatory areas in the lung tissue. No macroscopic lung lesions were observed in control or exposed pigs. The findings in the control pigs imply that even low dust concentrations and possibly peptidoglycan contamination can induce cellular changes in the BAL fluid and that a true control pig does not exist. In addition, the exposed pigs developed a mild eosinophilia, indicating an allergic response to the airborne contaminants. PMID:10369571

Jolie, R; Bäckström, L; Olson, L; Chase, C



Endotoxin-induced basal respiration alterations of renal HK-2 cells: A sign of pathologic metabolism down-regulation  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer A HK-2 cells model of inflammation-induced acute kidney injury. Black-Right-Pointing-Pointer Two oximetry methods: high resolution respirometry and ESR spectroscopy. Black-Right-Pointing-Pointer Oxygen consumption rates of renal cells decrease when treated with LPS. Black-Right-Pointing-Pointer Cells do not recover normal respiration when the LPS treatment is removed. Black-Right-Pointing-Pointer This basal respiration alteration is a sign of pathologic metabolism down-regulation. -- Abstract: To study the mechanism of oxygen regulation in inflammation-induced acute kidney injury, we investigate the effects of a bacterial endotoxin (lipopolysaccharide, LPS) on the basal respiration of proximal tubular epithelial cells (HK-2) both by high-resolution respirometry and electron spin resonance spectroscopy. These two complementary methods have shown that HK-2 cells exhibit a decreased oxygen consumption rate when treated with LPS. Surprisingly, this cellular respiration alteration persists even after the stress factor was removed. We suggested that this irreversible decrease in renal oxygen consumption after LPS challenge is related to a pathologic metabolic down-regulation such as a lack of oxygen utilization by cells.

Quoilin, C., E-mail: [Laboratory of Biomedical Spectroscopy, Department of Physics, University of Liege, 4000 Liege (Belgium); Mouithys-Mickalad, A. [Center of Oxygen Research and Development, Department of Chemistry, University of Liege, 4000 Liege (Belgium)] [Center of Oxygen Research and Development, Department of Chemistry, University of Liege, 4000 Liege (Belgium); Duranteau, J. [Department of Anaesthesia and Surgical ICU, CHU Bicetre, University Paris XI Sud, 94275 Le Kremlin Bicetre (France)] [Department of Anaesthesia and Surgical ICU, CHU Bicetre, University Paris XI Sud, 94275 Le Kremlin Bicetre (France); Gallez, B. [Biomedical Magnetic Resonance Group, Louvain Drug Research Institute, Universite catholique de Louvain, 1200 Brussels (Belgium)] [Biomedical Magnetic Resonance Group, Louvain Drug Research Institute, Universite catholique de Louvain, 1200 Brussels (Belgium); Hoebeke, M. [Laboratory of Biomedical Spectroscopy, Department of Physics, University of Liege, 4000 Liege (Belgium)] [Laboratory of Biomedical Spectroscopy, Department of Physics, University of Liege, 4000 Liege (Belgium)



Voluntarily produced increases in heart rate variability modulate autonomic effects of endotoxin induced systemic inflammation: an exploratory study.  


Exposure of healthy people to lipopolysaccharide (LPS; endotoxin) produces a pro-inflammatory response, subjective symptoms, and decreased heart rate variability (HRV). Given the efficacy of HRV biofeedback (BF) for treating asthma, the large autonomic effects of HRV BF, and the link between vagus nerve activity and inflammation, we hypothesized that HRV BF would dampen the acute manifestations of systemic inflammation induced by LPS challenge. Healthy participants age 18-40 were randomly assigned to four-one-hour training sessions of either HRV BF (n = 6) or a control 15/min paced breathing condition (n = 5) prior to acute experimentally induced LPS exposure. Participants were coached to do the procedures for 10 min each at five hourly time points after LPS injection, and then 2 h later. Subjective symptoms, HRV parameters, and plasma cytokine levels were measured at each time point, 2 h afterward, and the following morning. Participants were able to perform the procedures both during four pre-exposure training sessions and while experiencing LPS-induced symptoms. The HRV BF group showed significant attenuation of the LPS-induced decline in HRV for the 6 h following LPS exposure, suggesting that HRV BF decreased autonomic dysfunction produced by LPS-induced inflammation. HRV BF also reduced symptoms of headache and eye sensitivity to light, but did not affect LPS-induced levels of pro-inflammatory cytokines or symptoms of nausea, muscle aches, or feverishness. Further evaluation of HRV BF appears to be warranted among patients with inflammatory conditions. PMID:20635134

Lehrer, Paul; Karavidas, Maria Katsamanis; Lu, Shou-En; Coyle, Susette M; Oikawa, Leo O; Macor, Marie; Calvano, Steve E; Lowry, Stephen F



Behavioral conditioning of lipopolysaccharide-induced anorexia  

Microsoft Academic Search

One manifestation of the acute phase response, sickness behavior, is now considered an important response in the organism's overall attempt to reinstate homeostasis. This report aimed to determine whether the sickness behavior of anorexia was conditionable using the conditioned taste aversion paradigm. To investigate this phenomenon, lipopolysaccharide (LPS) (100 ?g\\/kg) was used as the unconditioned stimulus, and was paired with

Michael S. Exton; Diane F. Bull; Maurice G. King



Airborne Endotoxin from Indoor and Outdoor Environments:Effect of Sample Dilution on the Kinetic Limulus Amebocyte Lysate (LAL) Assay  

Technology Transfer Automated Retrieval System (TEKTRAN)

Airborne endotoxin in occupational environments are a potential respiratory hazard to individuals. In this study, total and inhalable airborne endotoxin samples were collected via filtration from inside animal housing units and downwind from agricultural production sites and a wastewater treatment ...


The Effect of Residual Endotoxin Contamination on the Neuroinflammatory Response to Sterilized Intracortical Microelectrodes.  


A major limitation to the use of microelectrode technologies in both research and clinical applications is our inability to consistently record high quality neural signals. There is increasing evidence that recording instability is linked, in part, to neuroinflammation. A number of factors including extravasated blood products and macrophage released soluble factors are believed to mediate neuroinflammation and the resulting recording instability. However, the roles of other inflammatory stimuli, such as residual endotoxin contamination, are poorly understood. Therefore, to determine the effect of endotoxin contamination we examined the brain tissue response of C57/BL6 mice to non-functional microelectrodes with a range of endotoxin levels. Endotoxin contamination on the sterilized microelectrodes was measured using a limulus amebocyte lysate test following FDA guidelines. Microelectrodes sterilized by autoclave, dry heat, or ethylene oxide gas, resulted in variable levels of residual endotoxins of 0.55 EU/mL, 0.22 EU/mL, and 0.11 EU/mL, respectively. Histological evaluation at two weeks showed a direct correlation between microglia/macrophage activation and endotoxin levels. Interestingly, astrogliosis, neuronal loss, and blood brain barrier dysfunction demonstrated a threshold-dependent response to bacterial endotoxins. However, at sixteen weeks, no histological differences were detected, regardless of initial endotoxin levels. Therefore, our results demonstrate that endotoxin contamination, within the range examined, contributes to initial but not chronic microelectrode associated neuroinflammation. Our results suggest that minimizing residual endotoxins may impact early recording quality. To this end, endotoxins should be considered as a potent stimulant to the neuroinflammatory response to implanted intracortical microelectrodes. PMID:24778808

Ravikumar, Madhumitha; Hageman, Daniel J; Tomaszewski, William H; Chandra, Gabriella M; Skousen, John L; Capadona, Jeffrey R



Effects of subacute ruminal acidosis challenges on fermentation and endotoxins in the rumen and hindgut of dairy cows.  


The effects of a grain-based subacute ruminal acidosis (SARA) challenge (GBSC) and an alfalfa-pellet SARA challenge (APSC) on fermentation and endotoxins in the rumen and in the cecum, as well as on endotoxins in peripheral blood, were determined. Six nonlactating Holstein cows with cannulas in the rumen and cecum were used in the study. A 3×3 Latin square arrangement of treatments with 4-wk experimental periods was adopted. During the first 3 wk of each experimental period, all cows received a diet containing 70% forages [dry matter (DM) basis]. In wk 4 of each period, cows received 1 of the following 3 diets: the 70% forage diet fed during wk 1 to 3 (control), a diet in which 34% of the dietary DM was replaced with grain pellets made of 50% ground wheat and 50% ground barely (GBSC), or a diet in which 37% of dietary DM was replaced with pellets of ground alfalfa (APSC). Rumen pH was monitored continuously using indwelling pH probes, and rumen fluid, blood, cecal digesta, and fecal grab samples were collected immediately before feed delivery at 0900 h and at 6 h after feed delivery on d 3 and 5 of wk 4. The time for which rumen pH was below 5.6 was 56.4, 225.2, and 298.8 min/d for the control, APSC, and GBSC treatments, respectively. Compared with the control, SARA challenges resulted in similar reductions in cecal digesta pH, which were 7.07, 6.86, and 6.79 for the control, APSC, and GBSC treatments, respectively. Compared with the control, only GBSC increased starch content in cecal digesta, which averaged 2.8, 2.6, and 7.4% of DM for the control, APSC, and GBSC, respectively. Free lipopolysaccharide endotoxin (LPS) concentration in rumen fluid increased from 10,405 endotoxin units (EU)/mL in the control treatment to 30,715 and 168,391 EU/mL in APSC and GBSC, respectively. Additionally, GBSC increased the LPS concentration from 16,508 to 118,522 EU/g in wet cecal digesta, and from 12,832 to 93,154 EU/g in wet feces. The APSC treatment did not affect LPS concentrations in cecal digesta and feces. All concentrations of LPS in blood plasma were below the detection limit of >0.05 EU/mL of the technique used. Despite the absence of LPS in blood, only GBSC increased the concentration of LPS-binding protein in blood plasma, which averaged, 8.9, 9.5, and 12.1mg/L for the control, APSC, and GBSC treatments, respectively. This suggests that GBSC caused translocation of LPS from the digestive tract but that LPS was detoxified before entering the peripheral blood circulation. The higher LPS concentration in cecal digesta in the GBSC compared with the APSC suggests a higher risk of LPS translocation in the large intestine in GBSC than in APSC. PMID:22192209

Li, S; Khafipour, E; Krause, D O; Kroeker, A; Rodriguez-Lecompte, J C; Gozho, G N; Plaizier, J C



Omega-3 Fatty Acid Intervention Suppresses Lipopolysaccharide-Induced Inflammation and Weight Loss in Mice  

PubMed Central

Bacterial endotoxin lipopolysaccharide (LPS)-induced sepsis is a critical medical condition, characterized by a severe systemic inflammation and rapid loss of muscle mass. Preventive and therapeutic strategies for this complex disease are still lacking. Here, we evaluated the effect of omega-3 (n-3) polyunsaturated fatty acid (PUFA) intervention on LPS-challenged mice with respect to inflammation, body weight and the expression of Toll-like receptor 4 (TLR4) pathway components. LPS administration induced a dramatic loss of body weight within two days. Treatment with n-3 PUFA not only stopped loss of body weight but also gradually reversed it back to baseline levels within one week. Accordingly, the animals treated with n-3 PUFA exhibited markedly lower levels of inflammatory cytokines or markers in plasma and tissues, as well as down-regulation of TLR4 pathway components compared to animals without n-3 PUFA treatment or those treated with omega-6 PUFA. Our data demonstrate that n-3 PUFA intervention can suppress LPS-induced inflammation and weight loss via, at least in part, down-regulation of pro-inflammatory targets of the TLR4 signaling pathway, and highlight the therapeutic potential of n-3 PUFA in the management of sepsis. PMID:25689565

Liu, Ying-Hua; Li, Xiang-Yong; Chen, Chih-Yu; Zhang, Hong-Man; Kang, Jing X.



Bound To Shock: Protection from Lethal Endotoxemic Shock by a Novel, Nontoxic, Alkylpolyamine Lipopolysaccharide Sequestrant?  

PubMed Central

Lipopolysaccharide (LPS), or endotoxin, a structural component of gram-negative bacterial outer membranes, plays a key role in the pathogenesis of septic shock, a syndrome of severe systemic inflammation which leads to multiple-system organ failure. Despite advances in antimicrobial chemotherapy, sepsis continues to be the commonest cause of death in the critically ill patient. This is attributable to the lack of therapeutic options that aim at limiting the exposure to the toxin and the prevention of subsequent downstream inflammatory processes. Polymyxin B (PMB), a peptide antibiotic, is a prototype small molecule that binds and neutralizes LPS toxicity. However, the antibiotic is too toxic for systemic use as an LPS sequestrant. Based on a nuclear magnetic resonance-derived model of polymyxin B-LPS complex, we had earlier identified the pharmacophore necessary for optimal recognition and neutralization of the toxin. Iterative cycles of pharmacophore-based ligand design and evaluation have yielded a synthetically easily accessible N1,mono-alkyl-mono-homologated spermine derivative, DS-96. We have found that DS-96 binds LPS and neutralizes its toxicity with a potency indistinguishable from that of PMB in a wide range of in vitro assays, affords complete protection in a murine model of LPS-induced lethality, and is apparently nontoxic in vertebrate animal models. PMID:17548488

Sil, Diptesh; Shrestha, Anurupa; Kimbrell, Matthew R.; Nguyen, Thuan B.; Adisechan, Ashok K.; Balakrishna, Rajalakshmi; Abbo, Benjamin G.; Malladi, Subbalakshmi; Miller, Kelly A.; Short, Shannon; Cromer, Jens R.; Arora, Shravan; Datta, Apurba; David, Sunil A.



Caffeine stimulates in vitro pituitary LH secretion in lipopolysaccharide-treated ewes.  


The study was designed to determine the effects of caffeine on luteinizing hormone (LH) secretion and gene expression of caffeine-associated receptors in anterior pituitary (AP) explants obtained from saline- and lipopolysaccharide (LPS)-treated ewes. Animals had been treated with LPS or saline daily for seven days. Three hours after the last injection of LPS/saline, the AP were collected and divided into four explants. The explants were incubated with: 1/medium-199 (control explants), 2/gonadotropin-releasing hormone (GnRH; 100pmol/mL; a positive control), 3/caffeine (10mmol/L), or 4/GnRH+caffeine. Caffeine stimulated (p<0.05) LH release by explants from both saline (19.7 vs. control 12.6ng/mg) and LPS (28.3 vs. control 13.9ng/mg) treated animals. The effect of caffeine on LH secretion was stronger in the LPS-treated group than in saline-treated group, and the observed LH release was similar to that induced by GnRH alone (27.2ng/mg). Caffeine increased (p<0.05) LH? gene expression only in explants from LPS-treated animals. In conclusion, the results of the present study demonstrated a stimulatory in vitro effect of caffeine on LH secretion by ovine pituitary explants. The potency of the caffeine-induced LH secretion was affected by in vivo treatment of the animals with endotoxin. PMID:25726373

Herman, Andrzej Przemys?aw; Herman, Anna; Skipor, Janina; Krawczy?ska, Agata; Bochenek, Joanna; Tomaszewska-Zaremba, Dorota



Lipopolysaccharide and Soluble CD14 in Cord Blood Plasma are associated with Prematurity and Chorioamnionitis  

PubMed Central

Background Lipopolysaccharide (LPS), an endotoxin of gram-negative bacteria, causes preterm birth in animals and has been implicated as a factor triggering preterm labor and systemic complications in humans. Little is known regarding LPS in the cord blood (CB) of term and preterm infants and its association with maternal and fetal characteristics. Methods CB was obtained from term (n=15) and preterm infants (n=76) after delivery. Plasma levels of LPS, C-Reactive Protein (CRP) and soluble CD14 (sCD14) were measured using commercially available kits (Limulus Amebocyte Lysate (LAL) assay and ELISA). Four linear regression models were created in order to identify independent variables that predict plasma LPS levels. Results CB LPS (24.48 vs. 1 pg/ml), CRP (87.9 vs. 47 ng/ml) and sCD14 (0.32 vs.0.35 µg/ml) levels were significantly higher in the preterm than the term infants. CB LPS levels correlate with gestational age, birth weight, CRP levels, sCD14 levels and the presence of both clinical and histological chorioamnionitis. Conclusion Our data suggest that LPS is associated with preterm labor and inflammation (CRP elevation and chorioamnionitis). These findings may be relevant to understand the role of LPS in prematurity and its possible role in preterm morbidities. PMID:24135785

Martinez, Denise G.; Funderburg, Nicholas T.; Cerissi, Adam; Rifaie, Reema; Aviles-Medina, Laura; Llorens-Bonilla, Braulio J.; Sleasman, John; Luciano, Angel A.



Zinc prevents sickness behavior induced by lipopolysaccharides after a stress challenge in rats.  


Sickness behavior is considered part of the specific beneficial adaptive behavioral and neuroimmune changes that occur in individuals in response to infectious/inflammatory processes. However, in dangerous and stressful situations, sickness behavior should be momentarily abrogated to prioritize survival behaviors, such as fight or flight. Taking this assumption into account, we experimentally induced sickness behavior in rats using lipopolysaccharides (LPS), an endotoxin that mimics infection by gram-negative bacteria, and then exposed these rats to a restraint stress challenge. Zinc has been shown to play a regulatory role in the immune and nervous systems. Therefore, the objective of this study was to examine the effects of zinc treatment on the sickness response of stress-challenged rats. We evaluated 22-kHz ultrasonic vocalizations, open-field behavior, tumor necrosis factor ? (TNF-?), corticosterone, and brain-derived neurotrophic factor (BDNF) plasma levels. LPS administration induced sickness behavior in rats compared to controls, i.e., decreases in the distance traveled, average velocity, rearing frequency, self-grooming, and number of vocalizations, as well as an increase in the plasma levels of TNF-?, compared with controls after a stressor challenge. LPS also decreased BDNF expression but did not influence anxiety parameters. Zinc treatment was able to prevent sickness behavior in LPS-exposed rats after the stress challenge, restoring exploratory/motor behaviors, communication, and TNF-? levels similar to those of the control group. Thus, zinc treatment appears to be beneficial for sick animals when they are facing risky/stressful situations. PMID:25775356

Kirsten, Thiago B; Galvăo, Marcella C; Reis-Silva, Thiago M; Queiroz-Hazarbassanov, Nicolle; Bernardi, Maria M



Omega-3 Fatty Acid intervention suppresses lipopolysaccharide-induced inflammation and weight loss in mice.  


Bacterial endotoxin lipopolysaccharide (LPS)-induced sepsis is a critical medical condition, characterized by a severe systemic inflammation and rapid loss of muscle mass. Preventive and therapeutic strategies for this complex disease are still lacking. Here, we evaluated the effect of omega-3 (n-3) polyunsaturated fatty acid (PUFA) intervention on LPS-challenged mice with respect to inflammation, body weight and the expression of Toll-like receptor 4 (TLR4) pathway components. LPS administration induced a dramatic loss of body weight within two days. Treatment with n-3 PUFA not only stopped loss of body weight but also gradually reversed it back to baseline levels within one week. Accordingly, the animals treated with n-3 PUFA exhibited markedly lower levels of inflammatory cytokines or markers in plasma and tissues, as well as down-regulation of TLR4 pathway components compared to animals without n-3 PUFA treatment or those treated with omega-6 PUFA. Our data demonstrate that n-3 PUFA intervention can suppress LPS-induced inflammation and weight loss via, at least in part, down-regulation of pro-inflammatory targets of the TLR4 signaling pathway, and highlight the therapeutic potential of n-3 PUFA in the management of sepsis. PMID:25689565

Liu, Ying-Hua; Li, Xiang-Yong; Chen, Chih-Yu; Zhang, Hong-Man; Kang, Jing X



Zinc Prevents Sickness Behavior Induced by Lipopolysaccharides after a Stress Challenge in Rats  

PubMed Central

Sickness behavior is considered part of the specific beneficial adaptive behavioral and neuroimmune changes that occur in individuals in response to infectious/inflammatory processes. However, in dangerous and stressful situations, sickness behavior should be momentarily abrogated to prioritize survival behaviors, such as fight or flight. Taking this assumption into account, we experimentally induced sickness behavior in rats using lipopolysaccharides (LPS), an endotoxin that mimics infection by gram-negative bacteria, and then exposed these rats to a restraint stress challenge. Zinc has been shown to play a regulatory role in the immune and nervous systems. Therefore, the objective of this study was to examine the effects of zinc treatment on the sickness response of stress-challenged rats. We evaluated 22-kHz ultrasonic vocalizations, open-field behavior, tumor necrosis factor ? (TNF-?), corticosterone, and brain-derived neurotrophic factor (BDNF) plasma levels. LPS administration induced sickness behavior in rats compared to controls, i.e., decreases in the distance traveled, average velocity, rearing frequency, self-grooming, and number of vocalizations, as well as an increase in the plasma levels of TNF-?, compared with controls after a stressor challenge. LPS also decreased BDNF expression but did not influence anxiety parameters. Zinc treatment was able to prevent sickness behavior in LPS-exposed rats after the stress challenge, restoring exploratory/motor behaviors, communication, and TNF-? levels similar to those of the control group. Thus, zinc treatment appears to be beneficial for sick animals when they are facing risky/stressful situations. PMID:25775356

Kirsten, Thiago B.; Galvăo, Marcella C.; Reis-Silva, Thiago M.; Queiroz-Hazarbassanov, Nicolle; Bernardi, Maria M.



Effects of caffeic acid phenethyl ester on lipopolysaccharide-induced lung injury in rats.  


Extracts of propolis, a natural beehive product, have been known for centuries to have a variety of beneficial medical properties, among which their anti-inflammatory effect is a major one. Caffeic acid phenethyl ester (CAPE), an active propolis component, has antimicrobial, anti-inflammatory, antioxidant, carcinostatic and immunomodulatory properties. In this study, we aimed to investigate the efficacy of CAPE in endotoxin-induced lung injury in rats. Lung injury was induced by a footpad injection of lipopolysaccharide (LPS). In the treatment group, 10 micromol kg(-1) CAPE was injected intraperitoneally immediately after LPS injection. At 24 h after LPS and/or CAPE injection, blood and lung tissue specimens were collected. MDA levels and MPO activity in serum and lung tissue, serum total antioxidant levels, lung tissue Na(+)/K(+) ATP-ase activity and histopathological evaluation were determined to assess the efficacy of CAPE treatment. CAPE was found to be efficient in reducing inflammation and lung tissue damage induced by LPS in rats. PMID:15953745

Koksel, Oguz; Ozdulger, Ali; Tamer, Lulufer; Cinel, Leyla; Ercil, Menderes; Degirmenci, Ulas; Unlu, Serdar; Kanik, Arzu



Dynamic modulation of innate immune response by varying dosages of lipopolysaccharide (LPS) in human monocytic cells.  


Innate monocytes and macrophages can be dynamically programmed into distinct states depending upon the strength of external stimuli. Innate programming may bear significant relevance to the pathogenesis and resolution of human inflammatory diseases. However, systems analyses with regard to the dynamic programming of innate leukocytes are lacking. In this study, we focused on the dynamic responses of human promonocytic THP-1 cells to lipopolysaccharide (LPS). We observed that varying dosages of LPS differentially modulate the expression of selected pro- and anti- inflammatory mediators such as IL-6 and IL-33. Super-low dosages of LPS preferentially induced the pro-inflammatory mediator IL-6, while higher dosages of LPS induced both IL-6 and IL-33. Mechanistically, we demonstrated that super-low and high doses of LPS cause differential activation of GSK3 and Akt, as well as the transcription factors FoxO1 and CREB. Inhibition of GSK3 enabled THP-1 cells to express IL-33 when challenged with super-low dose LPS. On the other hand, activation of CREB with adenosine suppressed IL-6 expression. Taken together, our study reveals a dynamic modulation of monocytic cells in response to varying dosages of endotoxin, and may shed light on our understanding of the dynamic balance that controls pathogenesis and resolution of inflammatory diseases. PMID:24970893

Morris, Matthew C; Gilliam, Elizabeth A; Button, Julia; Li, Liwu



Lipopolysaccharide binding of the mite allergen Der f 2.  


Lipid-binding properties and/or involvement with host defense are often found in allergen proteins, implying that these intrinsic biological functions likely contribute to the allergenicity of allergens. The group 2 major mite allergens, Der f 2 and Der p 2, show structural homology with MD-2, the lipopolysaccharide (LPS)-binding component of the Toll-like receptor (TLR) 4 signalling complex. Elucidation of the ligand-binding properties of group 2 mite allergens and identification of interaction sites by structural studies are important to explore the relationship between allergenicity and biological function. Here, we report a ligand-fishing approach in which His-tagged Der f 2 was incubated with sonicated stable isotope-labelled Escherichia coli as a potential ligand source, followed by isolation of Der f 2-bound material by a HisTrap column and NMR analysis. We found that Der f 2 binds to LPS with a nanomolar affinity and, using fluorescence and gel filtration assays that LPS binds to Der f 2 in a molar ratio of 1 : 1. We mapped the LPS-binding interface of Der f 2 by NMR perturbation studies, which suggested that LPS binds Der f 2 between the two large beta-sheets, similar to its binding to MD-2, the LPS-binding component of the innate immunity receptor TLR4. PMID:19678854

Ichikawa, Saori; Takai, Toshiro; Yashiki, Tomoe; Takahashi, Seizo; Okumura, Ko; Ogawa, Hideoki; Kohda, Daisuke; Hatanaka, Hideki



Ambient Endotoxin Concentrations and Assessment of Offsite Transport at Open-Lot and Open-Freestall Dairies.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Endotoxins are derived from gram-negative bacteria and are a potent inducer of inflammatory reactions in the respiratory tract when inhaled. To assess daily fluctuations of airborne endotoxin and their potential for transport from dairies, endotoxin concentrations were monitored over an 8-h period a...



Technology Transfer Automated Retrieval System (TEKTRAN)

In humans and sheep, administration of endotoxin results in increased concentrations of growth hormone (GH). Experiments were designed to determine the mechanism by which endotoxin increases concentrations of GH. To determine if cytokines mediated the effect of endotoxin on GH, sheep were challeng...


Marine aerosol as a possible source for endotoxins in coastal areas.  


Marine aerosols, that are very common in the highly populated coastal cities and communities, may contain biological constituents. Some of this biological fraction of marine aerosols, such as cyanobacteria and plankton debris, may influence human health by inflammation and allergic reactions when inhaled. In this study we identify and compare sources for endotoxins sampled on filters in an on-shore and more-inland site. Filter analysis included endotoxin content, total bacteria, gram-negative bacteria and cyanobacteria genome concentrations as well as ion content in order to identify possible sources for the endotoxins. Satellite images of chlorophyll-a levels and back trajectory analysis were used to further study the cyanobacteria blooms in the sea, close to the trajectory of the sampled air. The highest endotoxin concentrations found in the shoreline site were during winter (3.23±0.17 EU/m(3)), together with the highest cyanobacteria genome (1065.5 genome/m(3)). The elevated endotoxin concentrations were significantly correlated with cyanobacterial levels scaled to the presence of marine aerosol (r=0.90), as well as to chlorophyll-a (r=0.96). Filters sampled further inland showed lower and non-significant correlation between endotoxin and cyanobacteria (r=0.70, P value=0.19), suggesting decrease in marine-originated endotoxin, with possible contributions from other sources of gram-negative non-cyanobacteria. We conclude that marine cyanobacteria may be a dominant contributor to elevated endotoxin levels in coastal areas. PMID:25201818

Lang-Yona, Naama; Lehahn, Yoav; Herut, Barak; Burshtein, Noa; Rudich, Yinon



Expression of a Bacillus thuringiensis d-endotoxin gene by Bacillus pumilus  

E-print Network

Expression of a Bacillus thuringiensis d-endotoxin gene by Bacillus pumilus L.B. Selinger, G introduced into a rhizosphere-inhabiting Bacillus pumilus isolate to create a -endotoxin expression into Bacillus pumilus RB8. When carried on high copy number vectors, cry genes appeared to inhibit sporulation

Selinger, Brent


Personal Exposure to Dust and Endotoxin in Robusta and Arabica Coffee Processing Factories in Tanzania  

PubMed Central

Introduction: Endotoxin exposure associated with organic dust exposure has been studied in several industries. Coffee cherries that are dried directly after harvest may differ in dust and endotoxin emissions to those that are peeled and washed before drying. The aim of this study was to measure personal total dust and endotoxin levels and to evaluate their determinants of exposure in coffee processing factories. Methods: Using Sidekick Casella pumps at a flow rate of 2l/min, total dust levels were measured in the workers’ breathing zone throughout the shift. Endotoxin was analyzed using the kinetic chromogenic Limulus amebocyte lysate assay. Separate linear mixed-effects models were used to evaluate exposure determinants for dust and endotoxin. Results: Total dust and endotoxin exposure were significantly higher in Robusta than in Arabica coffee factories (geometric mean 3.41mg/m3 and 10 800 EU/m3 versus 2.10mg/m3 and 1400 EU/m3, respectively). Dry pre-processed coffee and differences in work tasks explained 30% of the total variance for total dust and 71% of the variance for endotoxin exposure. High exposure in Robusta processing is associated with the dry pre-processing method used after harvest. Conclusions: Dust and endotoxin exposure is high, in particular when processing dry pre-processed coffee. Minimization of dust emissions and use of efficient dust exhaust systems are important to prevent the development of respiratory system impairment in workers. PMID:23028014

Sakwari, Gloria



ToxinSensorTM Chromogenic LAL Endotoxin Assay Kit Cat. No. L00350, L00350C  

E-print Network

ENDOTOXIN QUANTITATIVE DETECTION PROTOCOL 1. Specimen Preparation All materials or diluents used for specimen collection and test reagent preparation must be endotoxin-free. Use aseptic technique at all times use, but need to be stored frozen if not used within 24 hours. Dissolve or dilute test specimen using

Lebendiker, Mario


Endotoxin Stimulates Liver Macrophages To Release Mediators That Inhibit an Early Step in Hepadnavirus Replication  

Microsoft Academic Search

Hepadnaviruses are known to be sensitive to various extracellular mediators. Therefore, bacterial endotoxin, which induces the secretion of proinflammatory mediators in the liver, was studied for its effect on hepadna- virus infection in vitro using the duck hepatitis B virus (DHBV) model. In initial experiments, endotoxin was shown to inhibit DHBV replication in primary duck hepatocyte cultures prepared by standard




Introduction Removal of endotoxin from solutions for animal studies, cell culture, transplanta-  

E-print Network

, vascular and respiratory epithelium, and arterial smooth muscle cells. For years, the Limulus amoebocyte with high recovery. Additionally, the S1 peptide is highly resistant to a wide range of pH's and ionic- duce endotoxin-free samples with high protein recovery. Endotoxin Removal from Proteins using Endo

Lebendiker, Mario


Endotoxin, Coliform, and Dust Levels in Various Types of Rodent Bedding  

PubMed Central

Endotoxins in grain dust, household dust, and animal bedding may induce respiratory symptoms in rodents and humans. We assayed the endotoxin, coliform, and dust levels in 20 types of rodent bedding. Endotoxin concentrations were measured by using a commercial test kit, coliform counts were determined by using conventional microbiologic procedures, and dust content was evaluated by using a rotating–tapping shaker. Paper bedding types contained significantly less endotoxin than did other bedding types; the highest levels of endotoxin were detected in hardwood and corncob beddings. The range of endotoxin content for each bedding type was: corncob bedding, 1913 to 4504 endotoxin units per gram (EU/g); hardwood bedding, 3121 to 5401 EU/g; corncob–paper mixed bedding, 1586 to 2416 EU/g; and paper bedding, less than 5 to 105 EU/g. Coliform counts varied from less than 10 to 7591 cfu/g in corncob beddings, 90 to 4010 cfu/g in corncob–paper mixed beddings, less than 10 to 137 cfu/g in hardwood beddings, and less than 10 cfu/g in paper beddings. Average dust content was less than 0.15% in all commercial bedding types. We conclude that paper bedding is the optimal bedding type for conducting LPS inhalation studies and that rodent bedding containing high levels of endotoxin may alter the results of respiratory and immunologic studies in rodents. PMID:20353693

Whiteside, Tanya E; Thigpen, Julius E; Kissling, Grace E; Grant, Mary G; Forsythe, Diane B



Bacterial lipopolysaccharides stimulate production of XCL1, a calcium-dependent lipopolysaccharide-binding serum lectin, in Xenopus laevis.  


Xenopus laevis serum lectin XCL1 is a newly identified molecule of the XCGL (or X-lectin) family, a unique group of Ca(2+)-dependent lectins that have a fibrinogen-like domain. The XCL1 protein was purified from lipopolysaccharide (LPS)-stimulated frog sera by sequential affinity chromatography on heparin-acrylic beads and galactose-Sepharose. XCL1 comprises multiple oligomeric proteins consisting of 37-kDa subunit polypeptides, as revealed by sodium dodecyl sulfate-polyacrylamide electrophoresis (SDS-PAGE) and Western blot analyses using the monoclonal antibody (mAb) produced against the recombinant XCL1 polypeptide. In the presence of Ca(2+), the protein bound to Escherichia coli, Staphylococcus aureus, LPS and galactose and the bound XCL1 was competitively eluted using ribose and xylose, and the elution was as efficient as that using EDTA, whereas elution using hexoses, GalNAc or GlcNAc was less effective. In reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analyses, XCL1 expression was ubiquitously detected in frog tissues, with relatively high levels in hematopoietic tissues including the spleen, liver and kidney. Intraperitoneal injection of E. coli, S. aureus or 100-300?g S-type LPS from various bacteria induced several-fold increases in serum XCL1 concentrations on day 3, and the elevated levels retained up to day 12. It also caused a remarkable increase of the splenic XCL1 expression on day 3, followed by a rapid decline to nearly nonstimulated control levels by day 7. The R-type LPS with shortened polysaccharide chains was less effective in inducing the serum XCL1 response, indicating that the sugar chains of LPS were important, if not essential, for the stimulation of XCL1 production. These results suggest that XCL1 is a pathogen recognition molecule involved in antimicrobial innate immunity in Xenopus. PMID:23454582

Nagata, Saburo; Nishiyama, Sayo; Ikazaki, Yumi



Density gradient enrichment of Escherichia coli lpxL mutants.  


We previously described enrichment of conditional Escherichia coli msbA mutants defective in lipopolysaccharide export using Ludox density gradients (Doerrler WT (2007) Appl Environ Microbiol 73; 7992-7996). Here, we use this approach to isolate and characterize temperature-sensitive lpxL mutants. LpxL is a late acyltransferase of the pathway of lipid A biosynthesis (The Raetz Pathway). Sequencing the lpxL gene from the mutants revealed the presence of both missense and nonsense mutations. The missense mutations include several in close proximity to the enzyme's active site or conserved residues (E137K, H132Y, G168D). These data demonstrate that Ludox gradients can be used to efficiently isolate conditional E. coli mutants with defects in lipopolysaccharide biosynthesis and provide insight into the enzymatic mechanism of LpxL. PMID:22554681

Six, David A; Lambert, Bliss; Raetz, Christian R H; Doerrler, William T



Pleiotropic Effects of a Mutation in rfaC on Escherichia coli Hemolysin  

Microsoft Academic Search

Several genes involved in the lipopolysaccharide (LPS) biosynthetic pathway have been shown to affect the expression or activity of Escherichia coli hemolysin (Hly), a secreted cytotoxin that is the prototype of the RTX family of toxins. To further study this relationship, E. coli K-12 strains harboring mutations in the LPS biosynthetic genes rfaS, rfaQ, rfaJ, rfaP, and rfaC were transformed




A new method for concentration analysis of bacterial endotoxins in perfluorocarbon  

NASA Astrophysics Data System (ADS)

This communication demonstrates the feasibility of the gel-clot method for the analysis of bacterial endotoxins in water extracts of perfluorocarbon which is a water insoluble liquid medical device. Perfluorocarbon (10 mL) was shaken with 10mL water for 15 min at 2000 r/min and the endotoxin present was extracted to the aqueous phase without interference inhibition/enhancement of the product and the recovery of endotoxin added to perfluorocarbon was determined. A validation study confirmed that endotoxins presented in perfluorocarbon pass over into the aqueous phase at concentrations of 20, 10 and 5 EU/mL with recoveries from 86.8% to 96.8%. Therefore, the gel-clot test is suitable for detecting bacterial endotoxins in perfluorocarbon which is a water insoluble medical device.

Chen, Dan-Dan; Feng, Xiao-Ming; Wang, Chun-Ren; Huang, Qing-Quan; Yang, Zhao-Peng; Meng, Qing-Yuan



Abortifacient effects of Vibrio cholerae exo-enterotoxin and endotoxin in mice.  


To study antifertility properties of microbial toxins, exoenterotoxin and endotoxin from Vibrio cholerae were injected intravenously into mice at different times during pregnancy. The two substances induced termination of pregnancy, but the patterns of abortifacient activity were different. Exotoxin terminated pregnancy in mice when administered between Days 4 and 10 of gestation, but abortifacient activity was reduced in animals more than 10 days pregnant; exogenous progesterone did not protect the pregnancies. Endotoxin was most effective in terminating pregnancy when injected after mid-gestation and the active principle was heat-stable; exogenous progesterone was not able to prevent the effects of endotoxin. Animals treated with endotoxin on Day 17 often gave birth to live young prematurely; indomethacin reduced the incidence of premature littering. The results demonstrate that exo- and endotoxins have antifertility properties and both appear to act on intrauterine targets rather than inducing progestin deficiency. PMID:1206628

Gasic, G J; Gasic, T B; Strauss, J F



Production and characterisation of mouse monoclonal antibodies reacting with the lipopolysaccharide core region of gram-negative bacilli.  


Monoclonal antibodies to the lipopolysaccharide (LPS) core region were produced by immunising mice with Escherichia coli strain J5 (chemotype Rc). One of these bound to the deepest part of the core, i.e., Lipid A, and reacted with other heat-killed but not live gram-negative bacilli, including E. coli, Klebsiella pneumoniae and Pseudomonas aeruginosa. Eight other monoclonal antibodies, binding to the terminal glucose residue of Rc LPS, reacted with live cells of E. coli strains only. Thus, the O antigen does not necessarily render the core inaccessible to antibody. However, despite binding to live bacteria, these monoclonal antibodies neither enhanced phagocytic killing, nor protected mice from dying from gram-negative infection or endotoxaemia. It is concluded that antibodies reacting with the most immunodominant parts of the J5 core are not protective. PMID:2455054

Appelmelk, B J; Verweij-van Vught, A M; Maaskant, J J; Schouten, W F; De Jonge, A J; Thijs, L G; Maclaren, D M



Alcohol, Intestinal Bacterial Growth, Intestinal Permeability to Endotoxin, and Medical Consequences  

PubMed Central

This report is a summary of the symposium on Alcohol, Intestinal Bacterial Growth, Intestinal Permeability to Endotoxin, and Medical Consequences, organized by National Institute on Alcohol Abuse and Alcoholism, Office of Dietary Supplements, and National Institute of Diabetes and Digestive and Kidney Diseases of National Institutes of Health in Rockville, Maryland, October 11, 2006. Alcohol exposure can promote the growth of Gram negative bacteria in the intestine which may result in accumulation of endotoxin. In addition, alcohol metabolism by Gram negative bacteria and intestinal epithelial cells can result in accumulation of acetaldehyde, which in turn can increase intestinal permeability to endotoxin by increasing tyrosine phosphorylation of tight junction and adherens junction proteins. Alcohol-induced generation of nitric oxide may also contribute to increased permeability to endotoxin by reacting with tubulin, which may cause damage to microtubule cytoskeleton and subsequent disruption of intestinal barrier function. Increased intestinal permeability can lead to increased transfer of endotoxin from the intestine to the liver and general circulation where endotoxin may trigger inflammatory changes in the liver and other organs. Alcohol may also increase intestinal permeability to peptidoglycan which can initiate inflammatory response in liver and other organs. In addition, acute alcohol exposure may potentiate the effect of burn injury on intestinal bacterial growth and permeability. Decreasing the number of Gram negative bacteria in the intestine can result in decreased production of endotoxin as well as acetaldehyde which is expected to decrease intestinal permeability to endotoxin. In addition, intestinal permeability may be preserved by administering epidermal growth factor, L-glutamine, oats supplementation, or zinc thereby preventing the transfer of endotoxin to the general circulation. Thus reducing the number of intestinal Gram negative bacteria and preserving intestinal permeability to endotoxin may attenuate alcoholic liver and other organ injuries. PMID:18504085

Purohit, Vishnudutt; Bode, J. Christian; Bode, Christiane; Brenner, David A.; Choudhry, Mashkoor A.; Hamilton, Frank; Kang, Y. James; Keshavarzian, Ali; Rao, Radhakrishna; Sartor, R. Balfour; Swanson, Christine; Turner, Jerrold R.



Structure and Function of Lipopolysaccharide Binding Protein  

NASA Astrophysics Data System (ADS)

The primary structure of lipopolysaccharide binding protein (LBP), a trace plasma protein that binds to the lipid A moiety of bacterial lipopolysaccharides (LPSs), was deduced by sequencing cloned complementary DNA. LBP shares sequence identity with another LPS binding protein found in granulocytes, bactericidal/permeability-increasing protein, and with cholesterol ester transport protein of the plasma. LBP may control the response to LPS under physiologic conditions by forming high-affinity complexes with LPS that bind to monocytes and macrophages, which then secrete tumor necrosis factor. The identification of this pathway for LPS-induced monocyte stimulation may aid in the development of treatments for diseases in which Gram-negative sepsis or endotoxemia are involved.

Schumann, Ralf R.; Leong, Steven R.; Flaggs, Gail W.; Gray, Patrick W.; Wright, Samuel D.; Mathison, John C.; Tobias, Peter S.; Ulevitch, Richard J.



Capillary Electrophoresis of Bacterial (Lipo)Polysaccharides  

Microsoft Academic Search

\\u000a Lipopolysaccharides (LPSs) are major components of the outer ­membrane of gram-negative bacteria, and, along with some acidic\\u000a polysaccharides, are important macromolecules belonging to bacteria. The recent emergence of modern ­analytical tools for\\u000a their study has produced a virtual explosion in the field of glycomics. Capillary electrophoresis (CE), due to its high resolving\\u000a power and sensitivity, has been useful in the

Nicola Volpi; Francesca Maccari


Immunoregulatory role of lactoferrin-lipopolysaccharide interactions  

Microsoft Academic Search

Lactoferrin (Lf) is a mammalian exclusive protein widely distributed in milk and exocrine secretions exhibiting multifunctional\\u000a properties. Many of the proven or proposed functions of Lf, apart from its iron binding activity, depend on its capacity to\\u000a bind to other macromolecules. Lf can bind and sequester lipopolysaccharide (LPS), thus preventing pro-inflammatory pathway\\u000a activation, sepsis and tissue damage. However, the interplay

Patrizia Puddu; Daniela Latorre; Piera Valenti; Sandra Gessani




Technology Transfer Automated Retrieval System (TEKTRAN)

Using a bovine intramammary Escherichia coli infection model, the effect of recombinant bovine soluble CD14 (rbosCD14) on milk somatic cell count (SCC), bacterial clearance and cytokine production was investigated. We first determined whether rbosCD14 would increase SCC during a lipopolysaccharide (...


Humidifier lung: possible contribution of endotoxin-induced lung injury.  


A 56-year-old man was admitted with cough, fever, myalgia, and arthralgia. Chest computed tomography demonstrated bilateral diffuse ground-glass opacities predominantly in the upper lungs. Subpleural non-segmental consolidation was observed in the late phase. Hypersensitivity pneumonitis was suspected, and an environmental provocation test with the incidental use of a home ultrasonic humidifier was positive. Unlike typical hypersensitivity pneumonitis, serum KL-6 levels were normal. Although several microorganisms were isolated from the humidifier water, there was no evidence for immune sensitization. We detected high amounts of endotoxin in the humidifier water, which may have contributed to the lung injury of this patient. PMID:12521211

Ohnishi, Hiroshi; Yokoyama, Akihito; Hamada, Hironobu; Manabe, Seiko; Ito, Ryoji; Watanabe, Akira; Katayama, Hitoshi; Yasuhara, Yoshifumi; Ikezoe, Junpei; Higaki, Jitsuo



Topical administration of diminazene aceturate decreases inflammation in endotoxin-induced uveitis  

PubMed Central

Purpose Our previous study demonstrated that an intraperitoneal injection of Diminazene Aceturate (DIZE) attenuated uveitis by activating ocular angiotensin-converting enzyme 2 (ACE2). Here, we investigated the anti-inflammatory effects on the ocular anterior segment of a topical administration of a DIZE solution and explored the downstream target molecules involved in the anti-inflammatory mechanism after ACE2 activation. Methods Endotoxin-induced uveitis (EIU) in rats was induced by a subcutaneous injection of lipopolysaccharides (LPS, 200 ?g) in 0.1 ml of sterile saline. DIZE (0.025, 0.05, or 0.1%) and dexamethasone (0.1%) solutions were applied topically (10 ?l eyedrops) to both eyes 6X every two hours before and after LPS injection. The inflammation of the ocular anterior segment was observed and the clinical scores were evaluated 24 h after LPS injection. The total protein concentration and levels of tumor necrosis factor-? (TNF-?) and interleukin-6 (IL-6) in the aqueous humor were determined. CD11b-positive cells adjacent to the iris ciliary body (ICB) were stained by immunohistochemistry. The mRNA levels of inflammatory cytokines and mediators, including IL-1?, TNF-?, COX-2, and iNOS or NF-?B subunit p65 in the ICB, were analyzed by real time RT–PCR. The protein expression of NF-?B p65 and the phosphorylated protein of p38 MAPK were detected by western blotting. Results A topical administration of DIZE decreased clinical scores and the total protein concentration, as well as TNF-? and IL-6 levels in the aqueous humor. Meanwhile, the mRNA levels of inflammatory cytokines and mediators, including IL-1?, TNF-?, COX-2, and iNOS in the ICB, were downregulated. DIZE reduced the recruitment of CD11b-positive cells adjacent to the ICB. Furthermore, DIZE downregulated the expressions of NF-?B subunit p65 at protein and mRNA levels and inhibited the phosphorylation of p38 MAPK protein in the ICB. Conclusions A topical administration of DIZE suppressed ocular inflammation in EIU and decreased the levels of inflammatory cytokines. DIZE attenuated the activation of NF-?B and p38 MAPK in EIU, which may be associated with ACE2-mediated anti-inflammatory effects. Our data provided further evidence that DIZE may represent a novel class of drug for the management of ocular inflammation.

Zheng, Changwei; Lei, Chunyan; Chen, Zihe; Zheng, Shijie; Yang, Hongxia; Qiu, Yiguo



E. Coli and Pregnancy  


... or visit us online at: . E. coli and Pregnancy In every pregnancy, a woman starts ... advice from your health care provider. What is E. coli? E. coli (Escherichia coli) is a bacterium that ...


Estimation of endotoxin inhalation from shower and humidifier exposure reveals potential risk to human health.  


This paper investigates potential exposure to endotoxin in drinking water through the inhalation of aerosols generated by showers and humidifiers. Adverse health effects attributable to the inhalation of airborne endotoxin in various occupational settings are summarized, as are controlled laboratory inhalation studies. Data from investigations estimating aerosolization of particulate matter by showers and humidifiers provide a basis for similar analyses with endotoxin, which like minerals in water, is nonvolatile. A theoretical assessment of the inhalation of aerosolized endotoxin showed that while the likelihood of an acute response while showering is minimal, the same is not true for humidifiers. Ultrasonic and impeller (cool mist) humidifiers efficiently produce large numbers of respirable particles. It is predicted that airway inflammation can occur if humidifier reservoirs are filled with tap water, sometimes even at typical drinking-water distribution-system endotoxin concentrations. Higher endotoxin levels occasionally found in drinking water (>1,000 EU/ml) are very likely to induce symptoms such as chills and fever if used as humidifier feed water. While it is unlikely that treated drinking water would contain extremely high endotoxin levels occasionally observed in cyanobacterial blooms (>35,000 EU/ml), the potential for serious acute health consequences exist if used in humidifiers. PMID:17878567

Anderson, William B; George Dixon, D; Mayfield, Colin I



Selective detection of endotoxin using an impedance aptasensor with electrochemically deposited gold nanoparticles.  


Using a single-stranded DNA (ssDNA) aptamer exhibiting high binding affinity (Kd?=?12?nM) to endotoxin as a probe, an impedance sensor where aptamer-conjugated gold nanoparticles (AuNPs) were electrochemically deposited on a gold electrode was fabricated and its performance in regard to endotoxin detection assessed. AuNPs have been employed widely as biosensors because of their unique physical and chemical properties. In order to maximize the performance of the impedance aptasensor on endotoxin detection, some critical factors affecting aptamer conjugation to AuNPs and target recognition ability (i.e. concentrations of aptamer coupled with AuNPs, pH, ion strength and cation effect at the time of aptamer-endotoxin interaction) were optimized. Electrochemical impendence spectroscopy, cyclic voltametry, atomic force microscope, scanning electron microscope and quartz crystal microbalance were employed to characterize all the modification/detection procedures during the sensor fabrication. The developed aptasensor showed a broad linear dynamic detection range (0.01-10.24?ng/ml) with a very low detection limit for endotoxin (0.005?ng/ml), despite the presence of several biomolecules (e.g. plasmid DNA, RNA, serum albumin, Glc and sucrose) known to interfere with other endotoxin assays. The demonstrated aptasensor required a detection time of only 10?min, providing a simple and fast analytical method to specifically detect endotoxin from complex biological liqors. PMID:23165992

Su, Wenqiong; Kim, Sung-Eun; Cho, MiSuk; Nam, Jae-Do; Choe, Woo-Seok; Lee, Youngkwan



Nonabsorbable antibiotics reduce bacterial and endotoxin translocation in hepatectomised rats.  


There is increasing evidence that septic complications, occurring after major hepatectomies, may be caused by gram negative bacteria, translocating from the gut. We investigated in rats, the effect of extended hepatectomy on the structure and morphology of the intestinal mucosa as well as on the translocation of intestinal bacteria and endotoxins. We also examined the effect of nonabsorbable antibiotics on reducing the intestinal flora and consequently the phenomenon of translocation by administering neomycin sulphate and cefazoline. Hepatectomy was found to increase translocation, while administration of nonabsorbable antibiotics decreased it significantly. In addition, hepatectomy increased the aerobic cecal bacterial population, which normalised in the group receiving antibiotics. Among the histological parameters evaluated, villus height demonstrated a significant reduction after hepatectomy, while the number of villi per cm and the number of mitoses per crypt, remained unchanged. Our results indicate that administration of nonabsorbable antibiotics presents a positive effect on bacterial and endotoxin translocation after extended hepatectomy, and this may be related to reduction of colonic bacterial load as an intraluminal effect of antibiotics. PMID:9298382

Kakkos, S K; Kirkilesis, J; Scopa, C D; Arvaniti, A; Alexandrides, T; Vagianos, C E



Variation in the ovine cortisol response to systemic bacterial endotoxin challenge is predominantly determined by signalling within the hypothalamic-pituitary-adrenal axis  

SciTech Connect

Bi-directional communication between the neuroendocrine and immune systems is designed, in part, to maintain or restore homeostasis during physiological stress. Exposure to endotoxin during Gram-negative bacterial infection for example, elicits the release of pro-inflammatory cytokines that activate the hypothalamic-pituitary-adrenal axis (HPAA). The secretion of adrenal glucocorticoids subsequently down regulates the host inflammatory response, minimizing potential tissue damage. Sequence and epigenetic variants in genes involved in regulating the neuroendocrine and immune systems are likely to contribute to individual differences in the HPAA response, and this may influence the host anti-inflammatory response to toxin exposure and susceptibility to inflammatory disease. In this study, high (HCR) and low (LCR) cortisol responders were selected from a normal population of 110 female sheep challenged iv with Escherichia coli endotoxin (400 ng/kg) to identify potential determinants that contribute to variation in the cortisol response phenotype. This phenotype was stable over several years in the HCR and LCR animals, and did not appear to be attributed to differences in expression of hepatic immune-related genes or systemic pro-inflammatory cytokine concentrations. Mechanistic studies using corticotrophin-releasing factor (0.5 {mu}g/kg body weight), arginine vasopressin (0.5 {mu}g/kg), and adrenocorticotropic hormone (0.5 {mu}g/kg) administered iv demonstrated that variation in this phenotype is largely determined by signalling within the HPAA. Future studies will use this ovine HCR/LCR model to investigate potential genetic and epigenetic variants that may contribute to variation in cortisol responsiveness to bacterial endotoxin.

You Qiumei [Centre for Genetic Improvement of Livestock, Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Karrow, Niel A. [Centre for Genetic Improvement of Livestock, Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada)], E-mail:; Cao Honghe [Centre for Genetic Improvement of Livestock, Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Rodriguez, Alexander [Department of Clinical Studies, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Mallard, Bonnie A. [Department of Pathobiology, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Boermans, Herman J. [Department of Biomedical Science, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada)



Induction of long-term lipopolysaccharide tolerance by an agonistic monoclonal antibody to the toll-like receptor 4/MD-2 complex.  


We have established an agonistic monoclonal antibody, UT12, that induces stimulatory signals comparable to those induced by lipopolysaccharide (LPS) through Toll-like receptor 4 and MD-2. UT12 activated nuclear factor kappaB and induced the production of proinflammatory cytokines such as tumor necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6) in peritoneal exudative cells. In addition, mice injected with UT12 rapidly fell into endotoxin shock concomitant with the augmentation of serum TNF-alpha and IL-6 levels, followed by death within 12 h. On the other hand, when the mice were pretreated with a sublethal dose of UT12, the mice survived the subsequent lethal LPS challenges, with significant suppression of serum TNF-alpha and IL-6, indicating that UT12 induced tolerance against LPS. This effect of UT12 was maintained for at least 9 days. In contrast, the tolerance induced by LPS continued for less than 3 days. These results illuminate a novel potential therapeutic strategy for endotoxin shock by the use of monoclonal antibodies against the Toll-like receptor 4/MD-2 complex. PMID:17028215

Ohta, Shoichiro; Bahrun, Uleng; Shimazu, Rintaro; Matsushita, Hidetomo; Fukudome, Kenji; Kimoto, Masao



Bacterial Surface Association of Heat-labile Enterotoxin through Lipopolysaccharide after Secretion via the General Secretory Pathway*  

PubMed Central

Heat-labile enterotoxin (LT) is an important virulence factor expressed by enterotoxigenic Escherichia coli. The route of LT secretion through the outer membrane and the cellular and extracellular localization of secreted LT were examined. Using a fluorescently labeled receptor, LT was found to be specifically secreted onto the surface of wild type enterotoxigenic Escherichia coli. The main terminal branch of the general secretory pathway (GSP) was necessary and sufficient to localize LT to the bacterial surface in a K-12 strain. LT is a heteromeric toxin, and we determined that its cell surface localization was mediated by the its B subunit independent of an intact GM1 ganglioside binding site and that LT binds lipopolysaccharide and GM1 concurrently. The majority of LT secreted into the culture supernatant by the GSP in E. coli associated with vesicles. Only a mutation in hns, not overexpression of the GSP or LT, caused an increase in vesicle yield, supporting a specific vesicle formation machinery regulated by the nucleoid-associated protein HNS. We propose a model in which LT is secreted by the GSP across the outer membrane, secreted LT binds lipopolysaccharide via a GM1-independent binding region on its B subunit, and LT on the surface of released outer membrane vesicles interacts with host cell receptors, leading to intoxication. These data explain a novel mechanism of vesicle-mediated receptor-dependent delivery of a bacterial toxin into a host cell. PMID:12087095

Horstman, Amanda L.; Kuehn, Meta J.



Tumor necrosis factor-alpha gene and protein expression in adult feline myocardium after endotoxin administration.  

PubMed Central

TNF alpha mRNA and protein biosynthesis were examined in the adult feline heart after stimulation with endotoxin. When freshly isolated hearts were stimulated with endotoxin in vitro, de novo TNF alpha mRNA expression occurred within 30 min, and TNF alpha protein production was detected within 60-75 min; however, TNF alpha mRNA and protein production were not detected in diluent-treated hearts. Immunohistochemical studies localized TNF alpha to endothelial cells, smooth muscle cells, and cardiac myocytes in the endotoxin-treated hearts, whereas TNF alpha immunostaining was absent in the diluent-treated hearts. To determine whether the cardiac myocyte was a source for TNF alpha production, two studies were performed. First, in situ hybridization studies, using highly specific biotinylated probes, demonstrated TNF alpha mRNA in cardiac myocytes from endotoxin-stimulated hearts; in contrast, TNF alpha mRNA was not expressed in myocytes from diluent-treated hearts. Second, TNF alpha protein production was observed when cultured cardiac myocytes were stimulated with endotoxin, whereas TNF alpha protein production was not detected in the diluent-treated cells. The functional significance of the intramyocardial production of TNF alpha was determined by examining cell motion in isolated cardiac myocytes treated with superfusates from endotoxin- and diluent-stimulated hearts. These studies showed that cell motion was depressed in myocytes treated with superfusates from the endotoxin-treated hearts, but was normal with the superfusates from the diluent-treated hearts; moreover, the negative inotropic effects of the superfusates from the endotoxin-treated hearts could be abrogated completely by pretreatment with an anti-TNF alpha antibody. Finally, endotoxin stimulation was also shown to result in the intramyocardial production of TNF alpha mRNA and protein in vivo. Thus, this study shows for the first time that the adult mammalian myocardium synthesizes biologically active TNF alpha. Images PMID:7635940

Kapadia, S; Lee, J; Torre-Amione, G; Birdsall, H H; Ma, T S; Mann, D L



Silicon deprivation does not significantly modify the acute white blood cell response but does modify tissue mineral distribution response to an endotoxin challenge.  


An experiment with rats was conducted to determine whether silicon deprivation affects the acute-phase immune response to an endotoxin challenge. Weanling female rats were assigned to two weight-matched groups of 24; one group was fed a basal diet containing about 1.9 microg Si/kg; the other group was fed the basal diet supplemented with 35 microg Si/kg as arginine silicate inositol complex. After being fed their respective diets for 8 weeks, 12 rats in each group were injected subcutaneously with 1 mg lipopolysaccharide (LPS)/kg body weight; the other 12 rats in each group were injected with deionized water. Two hours after injection, the rats were anesthetized with ether for collection of blood (for plasma), liver and femurs, and then euthanized by decapitation. LPS injection decreased total white blood cell, lymphocyte, monocyte, eosinophil, and basophil counts by 80-90%, but did not affect neutrophil counts. LPS injection also increased plasma tumor necrosis factor-alpha and osteopontin and decreased plasma hyaluronic acid. Silicon deprivation did not significantly affect any of these responses to LPS. Silicon in liver and silicon, iron, and zinc in femur were increased by LPS injection only in silicon-deprived rats. Silicon deprivation also increased monocyte counts and osteopontin and decreased femur zinc in rats not injected with LPS. The findings indicate that silicon deprivation does not affect the acute-immune phase decrease in inflammatory cell numbers and increase in inflammatory cytokines in response to an endotoxin challenge. Silicon deprivation, however, apparently causes slight chronic inflammation and might influence inflammatory cell proliferation in the chronic-phase inflammatory response. PMID:19688189

Nielsen, Forrest H



Damage of lipopolysaccharides in outer cell membrane and production of ROS-mediated stress within bacteria makes nano zinc oxide a bactericidal agent  

NASA Astrophysics Data System (ADS)

Zinc oxide nanoparticle (ZNP) has been synthesized by microwave-assisted technique with the aid of a buffer solution. ZNP inhibited the growth of bacterial system Escherichia coli, even its multidrug-resistant counterpart as well. Systematic evaluation reveals that bioavailable crystalline ZNP damages the lipopolysaccharide layer from outer membrane (OM) of E. coli, subsequently damages the OM followed by inner membrane, enters within the cell and generates extensive reactive oxygen species-mediated damage. A series of biochemical, biophysical and molecular techniques have been used to reach the conclusion. We believe this work is expected to enlighten the detailed mode of action study in bacterial system.

Patra, Prasun; Roy, Shuvrodeb; Sarkar, Sampad; Mitra, Shouvik; Pradhan, Saheli; Debnath, Nitai; Goswami, Arunava



Use of mucin and hemoglobin in experimental murine gram-negative bacteremia enhances the immunoprotective action of antibodies reactive with the lipopolysaccharide core region.  


An antiserum with a high content of antibodies, binding to the Gram-negative lipopolysaccharide core region, was prepared by immunizing rabbits with the rough Escherichia coli mutant J5. This antiserum was capable of protecting mice against lethal challenge doses of E. coli 0 111:B4 in a mouse model where the animals were compromised by means of mucin plus hemoglobin (LD 50 = 10(3) bacteria). However, no protection was observed in a non-compromised mouse model (LD 50 = 10(7) bacteria). This observation might explain why in the past so many discrepant results have been obtained in mouse protection studies with cross-reactive antisera. PMID:3545072

Appelmelk, B J; Verwey-van Vught, A M; Maaskant, J J; Schouten, W F; Thijs, L G; Maclaren, D M



Unresponsiveness of MyD88Deficient Mice to Endotoxin  

Microsoft Academic Search

MyD88 is a general adaptor protein that plays an important role in the Toll\\/IL-1 receptor family signalings. Recently, Toll-like receptors 2 and 4 (TLR2 and TLR4) have been suggested to be the signaling receptors for lipopolysaccharide (LPS). In this study, we demonstrate that MyD88 knockout mice lack the ability to respond to LPS as measured by shock response, B cell

Taro Kawai; Osamu Adachi; Tomohiko Ogawa; Kiyoshi Takeda; Shizuo Akira



Biophysical Mechanisms of the Neutralization of Endotoxins by Lipopolyamines  

E-print Network

peptides polymyxin B and its nonapeptide. Bio- phys. J., 2005, 88, 1845-1858. [24] Howe, J.; Garidel, P.; Wulf, M.; Gerber, S.; Milkereit, G.; Vill, V.; Roessle, M.; Brandenburg, K. Structural polymorphism of hydrated Biophysical Mechanisms.... Thermodynamic analysis of the lipopolysaccharide-dependent resistance of gram- negative bacteria against polymyxin B. Biophys. J., 2007, 92, 2796- 2805. [27] Brandenburg, K.; Andrä, J.; Müller, M.; Koch, M. H.J.; Garidel, P. Physicochemical properties...

Sil, Diptesh; Heinbockel, Lena; Kaconis, Yani; Rö ssle, Manfred; Garidel, Thomas; David, Sunil A.; Brandenburg, Klaus



The effect of endotoxin on heart rate dynamics in diabetic rats.  


The effect of endotoxin on heart rate variability (HRV) was assessed in diabetic and controls rats using a telemetric system. Endotoxin induced a reduction in sample entropy of cardiac rhythm in control animals. However, this effect was significantly blunted in streptozotocin-induced diabetic rats. Since uncoupling of cardiac pacemaker from cholinergic control is linked to reduced HRV in endotoxemia, chronotropic responsiveness to cholinergic stimulation was assessed in isolated atria. Endotoxemia was associated with impaired responsiveness to carbacholine in control rats. However, endotoxemia did not impair cholinergic responsiveness in diabetic atria. These findings corroborates with development of endotoxin tolerance in diabetic rats. PMID:25578644

Meamar, Morvarid; Dehpour, Tara; Mazloom, Roham; Sharifi, Fatemeh; Raoufy, Mohammad R; Dehpour, Ahmad R; Mani, Ali R



The molecular adsorption-type endotoxin detection system using immobilized ?-polylysine  

NASA Astrophysics Data System (ADS)

Hemodialysis for chronic renal failure is the most popular treatment method with artificial organs. However, hemodialysis patients must continue the treatment throughout their life, the results of long term extracorporeal dialysis, those patients develop the various complications and diseases, for example, dialysis amyloidosis etc. Dialysis amyloidosis is one of the refractory complications, and endotoxin is thought to be the most likely cause of it, recently. Endotoxin is one of the major cell wall components of gram-negative bacteria, and it has various biological activities. In addition, it is known that a mount of endotoxin exists in living environment, and medicine is often contaminated with endotoxin. When contaminated dialyzing fluids are used to hemodialysis, above-mentioned dialysis amyloidosis is developed. Therefore, it is important that the detection and removal of endotoxin from dialyzing fluids. Until now, the measurement methods using Limulus Amebosyte Lysate (LAL) reagent were carried out as the tests for the presence of endtoxin. However, these methods include several different varieties of measurement techniques. The following are examples of them, gelatinization method, turbidimetric assay method, colorimetric assay method and fluoroscopic method. However, these techniques needed 30-60 minutes for the measurement. From these facts, they are not able to use as a "real-time endotoxin detector". The detection of endotoxin has needed to carry out immediately, for that reason, a new detection method is desired. In this research, we focused attention to adsorption reaction between ?-polylysine and endotoxin. ?-polylysine has the structure of straight chain molecule composed by 25-30 residues made by lysine, and it is used as an antimicrobial agent, moreover, cellulose beads with immobilized ?-polylysine is used as the barrier filter for endotoxin removal. The endotoxin is adsorbed to immobilized ?-polylysine, as the result of this reaction, the mass incrementation is occurred, and the existence of endtoxin can be detected immediately, by using of Quartz Crystal Microbalance (QCM). In this report, the immobilization of ?-polylysine onto the Au and Si substrate and its adsorptive activity are described. We use X-ray Photoelectron Spectroscopy (XPS) to confirm the ?-polylysine immobilization, and the adsorptive activity of immobilized ?-polylysine is measured by AFM and QCM. This molecular adsorption type endotoxin sensor aims to the realization of "real-time endotoxin detection system".

Ooe, Katsutoshi; Tsuji, Akihito; Nishishita, Naoki; Hirano, Yoshiaki



Effects of various starch feeding regimens on responses of dairy cows to intramammary lipopolysaccharide infusion.  


Endotoxin tolerance (ET) can develop in mammals that have been challenged repeatedly with sublethal amounts of lipopolysaccharide (LPS). Previous research has shown that subclinical ruminal acidosis can increase circulating concentrations of LPS. We investigated whether ET would develop in Holstein cows that were subjected to chronic subacute ruminal acidosis (SARA) or acute SARA followed by intramammary infusion of LPS. Twenty-four cows, both primiparous and multiparous, were assigned to 8 blocks of 3 cows. Cows within blocks were randomly assigned to 1 of 3 treatments: (1) control (diet DM was 24% starch and 35% NDF), (2) high starch (formulated to induce chronic milk fat depression with 29% starch and 32% NDF), and (3) acidosis (designed to cause acute bouts of milk fat depression by short-term feeding of a diet with 32% starch, some of which came from wheat grain, and 30% NDF). Cows on the control and high-starch treatments were fed their respective diets throughout the 24-d trial. The acidosis cows were fed the control diet during most of the experiment, except during two 2-d bouts (d 10 and 11 and 17 and 18 of the experiment) in which a high-starch diet was fed. Cows on the high-starch and acidosis treatments produced milk fat with an altered fatty acid profile indicative of SARA (e.g., increased concentrations of specific trans, and odd-, and branched-chain fatty acids), but only cows on the high-starch treatment had milk fat depression. Concentrations of serum amyloid A were elevated in cows on the acidosis treatment, but did not differ between control and high-starch cows. On d 20 of the experiment, all cows were given an intramammary infusion of 10 µg of LPS into 1 mammary quarter 3h after morning milking. Milk yield and DMI decreased the day of the infusion, but the response was not affected by dietary treatment. No systemic indicators of ET were observed among treatments, but evidence of an ET response at the local level of the mammary gland was observed. Cows fed the control diet had higher concentrations of serum amyloid A in milk 12 and 24h postinfusion than did cows fed the high-starch diet and higher concentrations than cows on the acidosis treatment at 12h postinfusion. Our data suggest cows that experienced varying degrees of SARA (based on altered milk fatty acid profile) and subsequent experimental endotoxin mastitis experienced a blunted inflammatory response at the level of the mammary gland, but not a systemic reduction in some inflammatory mediators. PMID:25547311

Gott, P N; Hogan, J S; Weiss, W P



Site-directed mutations in a highly conserved region of Bacillus thuringiensis delta-endotoxin affect inhibition of short circuit current across Bombyx mori midguts.  

PubMed Central

Bacillus thuringiensis delta-endotoxins (Cry toxins) are insecticidal proteins of approximately 65 kDa in the proteolytically processed and active form. The structure of one of these toxins, CryIIIA, has been determined by Li et al. [Li, J., Carroll, J. & Ellar, D. J. (1991) Nature (London) 353, 815-821] and contains three domains. It is believed that other delta-endotoxins adopt similar three-dimensional structure. Li et al. proposed that the first domain is the membrane pore-forming domain. Previous work from our laboratory has shown that the second domain is the receptor binding domain, but the function of the third domain is unclear. Site-directed mutagenesis was used to convert the "arginine face" of one of five highly conserved regions, QRYRVRIRYAS of CryIAa (residues 525-535), to selected other residues. This sequence corresponds to the beta-sheet 17 of CryIIIA in the third domain. Mutations in the second and third arginine positions resulted in structural alterations in the protein and were poorly expressed in Escherichia coli. Toxins from genes mutated to replace lysine for the first and fourth arginines were unaltered in expression and structure, as measured by trypsin activation, CD spectra, and receptor binding, but were substantially reduced in their insecticidal properties and inhibition of short circuit current across Bombyx mori midguts. It is proposed that this region plays a role in toxin function as an ion channel. PMID:8415651

Chen, X J; Lee, M K; Dean, D H



In vivo effects of intravascularly applied Escherichia coli hemolysin: dissociation between induction of granulocytopenia and lethality in monkeys  

Microsoft Academic Search

The effects of intravascular application of endotoxin-depleted Escherichia coli hemolysin (HlyA) was studied in rabbits and monkeys. In rabbits, bolus application of HlyA calculated to effect final blood levels of approximately 2-3 HU\\/ml (200–300 ng\\/ml) caused an acute fall of polymorphonuclear blood leukocytes to less than 20% of starting levels within 5 min. Additionally, platelet counts dropped to approximately 30%

Dierk Vagts; Hans-Peter Dienes; Peter J. Barth; Hansjörg Ronneberger; Klaus-Dieter Hungerer; Sucharit Bhakdi



Suppression of Ca(2+) influx in endotoxin-treated mouse cerebral cortex endothelial bEND.3 cells.  


Release of nitric oxide (NO) is triggered by a rise in endothelial cell (EC) cytosolic Ca(2+) concentration ([Ca(2+)]i) and is of prime importance in vascular tone regulation as NO relaxes vascular smooth muscle. Agonists could stimulate EC [Ca(2+)]i elevation by triggering Ca(2+) influx via plasma membrane ion channels, one of which is the store-operated Ca(2+) channel; the latter opens as a result of agonist-triggered internal Ca(2+) release. Endotoxin (lipopolysaccharide, LPS) could cause sepsis, which is often the fatal cause in critically ill patients. One of the LPS-induced damages is EC dysfunction, eventually leading to perturbations in hemodynamics. We obtained data showing that LPS-challenged mouse cerebral cortex endothelial bEND.3 cells did not suffer from apoptotic death, and in fact had intact agonist-triggered intracellular Ca(2+) release; however, they had reduced store-operated Ca(2+) entry (SOCE) after LPS treatment for 3h or more. Using real-time PCR, we did not find a decrease in gene expression of stromal interaction molecule 1 (STIM1) and Orai1 (two SOCE protein components) in bEND.3 cells treated with LPS for 15h. LPS inhibitory effects could be largely prevented by sodium salicylate (an inhibitor of nuclear factor-?B; NF-?B) or SB203580 (an inhibitor of p38 mitogen-activated protein kinases; p38 MAPK), suggesting that the p38 MAPK-NF-?B pathway is involved in SOCE inhibition. PMID:25771453

Tsai, Tien-Yao; Lou, Shyh-Liang; Wong, Kar-Lok; Wang, Mei-Ling; Su, Tzu-Hui; Liu, Zhong-Min; Yeh, Li-Jen; Chan, Paul; Gong, Chi-Li; Leung, Yuk-Man



Treatment of low molecular weight heparin inhibits systemic inflammation and prevents endotoxin-induced acute lung injury in rats.  


To determine whether low molecular weight heparin (LMWH) is able to reduce pulmonary inflammation and improve the survival in rats with endotoxin-induced acute lung injury (ALI). Rat ALI model was reproduced by injection of lipopolysaccharide (LPS) into tail vein. Rats were divided randomly into three groups: control group, ALI group, LMWH-treated group. Blood was collected and lung tissue was harvested at the designated time points for analysis. The lung specimens were harvested for morphological studies, streptavidin-peroxidase immunohistochemistry examination. Lung tissue edema was evaluated by tissue water content. The levels of lung tissue myeloperoxidase (MPO) were determined. Meanwhile, the nuclear factor-kappa B (NF-?B) activation, tumor necrosis factor-? (TNF-?), interleukin-1? (IL-1?) levels and high mobility group box 1 (HMGB1) and intercellular adhesion molecule-1 (ICAM-1) protein levels in the lung were studied. In survival studies, a separate group of rats were treated with LMWH or sterile saline after LPS administration. Then, the mortality was recorded. Treatment with LMWH after ALI was associated with a reduction in the severity of LPS-induced lung injury. Treatment with LMWH significantly decreased the expression of TNF-?, IL-1?, HMGB1 and ICAM-1 in the lung of ALI rats. Similarly, treatment with LMWH dramatically diminished LPS-induced neutrophil sequestration and markedly reduced the enhanced lung permeability. In the present study, LMWH administration inhibited the nuclear translocation of NF-?B in the lung. Survival was significantly higher among the LMWH-treated group compared with the ALI group. These data suggest that LMWH attenuates inflammation and prevents lethality in endotoxemic rats. PMID:24425537

Luan, Zheng-Gang; Naranpurev, Mendsaikhan; Ma, Xiao-Chun



Inhaled Hydrogen Sulfide Prevents Endotoxin-Induced Systemic Inflammation and Improves Survival by Altering Sulfide Metabolism in Mice  

PubMed Central

Abstract Aims: The role of hydrogen sulfide (H2S) in endotoxin (lipopolysaccharide [LPS])-induced inflammation is incompletely understood. We examined the impact of H2S breathing on LPS-induced changes in sulfide metabolism, systemic inflammation, and survival in mice. Results: Mice that breathed air alone exhibited decreased plasma sulfide levels and poor survival rate at 72?h after LPS challenge. Endotoxemia markedly increased alanine aminotransferase (ALT) activity and nitrite/nitrate (NOx) levels in plasma and lung myeloperoxidase (MPO) activity in mice that breathed air. In contrast, breathing air supplemented with 80?ppm of H2S for 6?h after LPS challenge markedly improved survival rate compared to mice that breathed air alone (p<0.05). H2S breathing attenuated LPS-induced increase of plasma ALT activity and NOx levels and lung MPO activity. Inhaled H2S suppressed LPS-induced upregulation of inflammatory cytokines, while it markedly induced anti-inflammatory interleukin (IL)-10 in the liver. Beneficial effects of H2S inhalation after LPS challenge were associated with restored sulfide levels and markedly increased thiosulfate levels in plasma. Increased thiosulfate levels after LPS challenge were associated with upregulation of rhodanese, but not cystathionine-?-lyase (CSE), in the liver. Administration of sodium thiosulfate dose-dependently improved survival after LPS challenge in mice. Innovation: By measuring changes in plasma levels of sulfide and sulfide metabolites using an advanced analytical method, this study revealed a critical role of thiosulfate in the protective effects of H2S breathing during endotoxemia. Conclusion: These observations suggest that H2S breathing prevents inflammation and improves survival after LPS challenge by altering sulfide metabolism in mice. Antioxid. Redox Signal. 17, 11—21. PMID:22221071

Tokuda, Kentaro; Kida, Kotaro; Marutani, Eizo; Crimi, Ettore; Bougaki, Masahiko; Khatri, Ashok; Kimura, Hideo



Biomarkers of oxidative stress study VI. Endogenous plasma antioxidants fail as useful biomarkers of endotoxin-induced oxidative stress.  


This is the newest report in a series of publications aiming to identify a blood-based antioxidant biomarker that could serve as an in vivo indicator of oxidative stress. The goal of the study was to test whether acutely exposing Göttingen mini pigs to the endotoxin lipopolysaccharide (LPS) results in a loss of antioxidants from plasma. We set as a criterion that a significant effect should be measured in plasma and seen at both doses and at more than one time point. Animals were injected with two doses of LPS at 2.5 and 5µg/kg iv. Control plasma was collected from each animal before the LPS injection. After the LPS injection, plasma samples were collected at 2, 16, 48, and 72h. Compared with the controls at the same time point, statistically significant losses were not found for either dose at multiple time points in any of the following potential markers: ascorbic acid, tocopherols (?, ?, ?), ratios of GSH/GSSG and cysteine/cystine, mixed disulfides, and total antioxidant capacity. However, uric acid, total GSH, and total Cys were significantly increased, probably because LPS had a harmful effect on the liver. The leakage of substances from damaged cells into the plasma may have increased plasma antioxidant concentrations, making changes difficult to interpret. Although this study used a mini-pig animal model of LPS-induced oxidative stress, it confirmed our previous findings in different rat models that measurement of antioxidants in plasma is not useful for the assessment of oxidative damage in vivo. PMID:25614459

Kadiiska, Maria B; Peddada, Shyamal; Herbert, Ronald A; Basu, Samar; Hensley, Kenneth; Jones, Dean P; Hatch, Gary E; Mason, Ronald P



Inhibition of Aldose Reductase Prevents Endotoxin-Induced Inflammation by Regulating Arachidonic Acid Pathway in Murine Macrophages  

PubMed Central

Bacterial endotoxin, lipopolysaccharide (LPS) is known to induce release of arachidonic acid (AA) and its metabolic products which play important role in inflammatory process. We have shown earlier that LPS-induced signals in macrophages are mediated by aldose reductase (AR). Here we have investigated the role of AR in LPS-induced release of AA metabolites and their modulation using a potent pharmacological inhibitor fidarestat and AR-siRNA ablation in RAW 264.7 macrophages, and AR-knockout mice peritoneal macrophages and heart tissue. Inhibition or genetic ablation of AR prevented the LPS-induced synthesis and release of AA metabolites such as PGE2, TXB, PGI2 and LTBs in macrophages. LPS-induced activation of cPLA2 was also prevented by AR inhibition. Similarly, AR inhibition also prevented the calcium ionophore A23187 –induced cPLA2 and LTB4 in macrophages. Further, AR inhibition with fidarestat prevented the expression of AA metabolizing enzymes such as COX-2 and LOX-5 in RAW 264.7 cells and AR-knockout mice derived peritoneal macrophages. LPS-induced expression of AA metabolizing enzymes and their catalyzed metabolic products