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Lipopolysaccharide Endotoxins  

PubMed Central

Summary Since lipopolysaccharide endotoxins of Gram-negative bacteria were last reviewed in this series in 1990, much has been learned about the assembly and signaling functions of these remarkable glycoconjugates. Lipopolysaccharides typically consist of a hydrophobic domain known as lipid A (or endotoxin), a non-repeating “core” oligosaccharide, and a distal polysaccharide (or O-antigen). The flood of recent genomic data has made it possible to study lipopolysaccharide assembly in diverse Gram-negative bacteria, many of which are human or plant pathogens, and to create mutants or hybrid constructs with novel properties. Unexpectedly, key genes for lipid A biosynthesis have also been found in higher plants, indicating that eucaryotic lipid A-like molecules may exist. The carbohydrate diversity of lipopolysaccharides is better appreciated now than ten years ago, but much remains to be learned about function. Sequence comparisons suggest that extensive lateral transfer of genes for the assembly of O-antigens has occurred among bacteria. The most significant finding in the field of endotoxin biology since 1990 has been the identification of the plasma membrane protein TLR4 as the lipid A signaling receptor of animal cells. The latter belongs to a family of innate immunity receptors, all of which possess a large extracellular domain of leucine-rich repeats, a single trans-membrane segment and a smaller cytoplasmic signaling region that engages the adaptor protein MyD88. The expanding knowledge of TLR4 specificity and its downstream signaling pathways should provide new opportunities for blocking the inflammatory side effects of sepsis. Future progress will require insights into lipopolysaccharide-protein recognition at the atomic level, greater understanding of intra- and inter-cellular lipopolysaccharide trafficking, and incisive biological approaches that combine the tools of bacterial and animal genetics.

Raetz, Christian R. H.; Whitfield, Chris



Effects of Aging on Endotoxin Tolerance Induced by Lipopolysaccharides Derived from Porphyromonas gingivalis and Escherichia coli  

PubMed Central

Background Periodontitis is a bacterially induced chronic inflammatory disease. Exposure of the host to periodontal pathogens and their virulence factors induces a state of hyporesponsiveness to subsequent stimulations, termed endotoxin tolerance. Aging has a profound effect on immune response to bacteria challenge. The aim of this study was to explore the effects of aging on endotoxin tolerance induced by Porphyromonas gingivalis (P. gingivalis) lipopolysaccharide (LPS) and Escherichia coli (E. coli) LPS in murine peritoneal macrophages. Methodology/Principal Findings We studied the cytokine production (TNF-?and IL-10) and Toll-like receptor 2, 4 (TLR2, 4) gene and protein expressions in peritoneal macrophages from young (2-month-old) and middle-aged (12-month-old) ICR mice following single or repeated P. gingivalis LPS or E. coli LPS stimulation. Pretreatment of peritoneal macrophages with P. gingivalis LPS or E. coli LPS resulted in a reduction in TNF-? production and an increase in IL-10 production upon secondary stimulation (p<0.05), and the markedly lower levels of TNF-? and higher levels of IL-10 were observed in macrophages from young mice compared with those from middle-aged mice (p<0.05). In addition, LPS restimulations also led to the significantly lower expression levels of TLR2, 4 mRNA and protein in macrophages from young mice (p<0.05). Conclusions/Significance Repeated LPS stimulations triggered endotoxin tolerance in peritoneal macrophages and the ability to develop tolerance in young mice was more excellent. The impaired ability to develop endotoxin tolerance resulted from aging might be related to TLR2, 4 and might lead to the incontrollable periodontal inflammation in older adults.

Sun, Ying; Li, Hui; Yang, Mi-Fang; Shu, Wei; Sun, Meng-Jun; Xu, Yan



Interaction of Ionizing Radiation and E. Coli Endotoxin. I. Effect of Radiation on Endotoxin Shock.  

National Technical Information Service (NTIS)

The possible interaction of E. coli endotoxin and total body irradiation has been studied in 38 adult mongrel dogs. Results indicate that prior irradiation (1000 r) abolishes the endotoxin shock syndrome, and the dogs die of radiation sickness on an avera...

J. A. Vick H. P. Ciuchta C. C. Berdjis



Tiratricol neutralizes bacterial endotoxins and reduces lipopolysaccharide-induced TNF-alpha production in the cell.  


The screening of a commercially available library of compounds has proved a successful strategy for the identification of a lead compound in a drug discovery programme. Here, we analysed 880 off-patent drugs, which initially comprised the Prestwick Chemical library, as sources of bacterial endotoxin neutralizers. We identified 3,3',5-triiodo-thyroacetic acid (tiratricol) as a non-antibacterial compound that neutralizes the toxic lipopolysaccharide. PMID:18844678

Cascales, Laura; Mas-Moruno, Carlos; Tamborero, Silvia; Aceńa, José Luis; Sanz-Cervera, Juan F; Fustero, Santos; Cruz, Luis J; Mora, Puig; Albericio, Fernando; Pérez-Payá, Enrique



Isolation and endotoxin activities of lipopolysaccharides from cyanobacterial cultures and complex water blooms and comparison with the effects of heterotrophic bacteria and green alga.  


Massive cyanobacterial water blooms are serious environmental and health problems worldwide. While some cyanobacterial toxins such as peptide microcystins have been investigated extensively, other toxic components of cyanobacteria (e.g. lipopolysaccharides, LPS) are poorly understood. The present study characterized endotoxin activities of LPS isolated from (i) laboratory cyanobacterial cultures, (ii) cyanobacterial water bloom samples dominated by Microcystis sp., Planktothrix sp., Aphanizomenon sp. and Anabaena sp., (iii) heterotrophic Gram-negative bacteria Escherichia coli, Kluyvera intermedia, Pseudomonas putida and Pseudomonas fluorescens and (iv) green alga Pseudokirchneriella subcapitata. Toxicity results derived with Limulus amebocyte lysate assay (LAL-test) showed that endotoxin activities of LPS from both cyanobacteria and heterotrophic bacteria were comparable and the values were within a similar range (1 x 10(3)-1 x 10(6) Endotoxin Units, EU, per mg of isolated LPS). The highest activities among the cyanobacterial samples were observed in the Aphanizomenon sp. dominated water bloom. The results also suggest generally higher endotoxin activities in complex natural samples than in laboratory cyanobacterial cultures. Further, experiments with the eukaryotic green alga P. subcapitata demonstrated a need for careful purification of the LPS extracts prior to testing with the LAL assay as several contaminants may overestimate endotoxin activities. This study shows relatively high pyrogenicity of LPS from various cyanobacteria. Further research should focus on detailed toxicological and ecotoxicological characterization of LPS in massive cyanobacterial water blooms. PMID:17461433

Bernardová, Katerina; Babica, Pavel; Marsálek, Blahoslav; Bláha, Ludek



Diphosphoryl lipid A obtained from the nontoxic lipopolysaccharide of Rhodopseudomonas sphaeroides is an endotoxin antagonist in mice.  

PubMed Central

Diphosphoryl lipid A (DPLA) obtained from the nontoxic lipopolysaccharide (LPS) of Rhodopseudomonas sphaeroides ATCC 17023 did not induce interleukin-1 release by murine peritoneal macrophages. However, it blocked this induction by toxic deep-rough chemotype LPS (ReLPS) from Escherichia coli D31m4. Previously, we obtained similar results on the induction of tumor necrosis factor (TNF) by macrophages. These results showed that DPLA is able to block in vitro the induction of two important mediators of gram-negative bacterial sepsis. We then wanted to determine whether DPLA could also block the induction of TNF by LPS in animals. Mice were treated with 100 micrograms of R. sphaeroides DPLA and challenged 60 min later with 1.0 micrograms of ReLPS from E. coli. The serum TNF level was measured after 60 min. Treatment of mice with this DPLA blocked the rapid and transient rise of TNF caused by ReLPS. This result suggested that R. sphaeroides DPLA might be able to protect animals against endotoxin shock caused by gram-negative bacterial infection.

Qureshi, N; Takayama, K; Kurtz, R



Action of propolis and medications against Escherichia coli and endotoxin in root canals.  


This study evaluated the action of propolis and intracanal medications against Escherichia coli and endotoxin. Forty-eight dental roots were contaminated with E. coli. The root canals were instrumented with propolis and divided into groups according to the type of intracanal medication: Ca(OH)(2), polymyxin B, or Ca(OH)(2) + 2% chlorhexidine gel. In the control group, saline solution was used without application of intracanal medication. Counts of colony-forming units were carried out and the endotoxin was quantified by the chromogenic Limulus amobocyte lysate assay. The results were evaluated by analysis of variance and the Dunn test (5%). Root canal irrigation with propolis was effective to completely eliminate E. coli and reduce the amount of endotoxins. All intracanal medications contributed to the significant decrease in endotoxins. Only intracanal medications may reduce the amount of endotoxins in the root canals. The greatest efficacy was observed for medications containing Ca(OH)(2). PMID:20868987

Valera, Marcia Carneiro; da Rosa, Jucely Aparecida; Maekawa, Lilian Eiko; de Oliveira, Luciane Dias; Carvalho, Cláudio Antonio Talge; Koga-Ito, Cristiane Yumi; Jorge, Antonio Olavo Cardoso



Effect of Escherichia coli endotoxin on cochlear potentials following its application to the chinchilla middle ear  

Microsoft Academic Search

The compound action potential (CAP) of the eighth nerve and the endocochlear potential (EP) were examined in the chinchilla as an animal model when Escherichia coli endotoxin (100µg) was applied to the middle ear cavity. A significant elevation of the CAP threshold at 2, 3, and 4 kHz was observed 48h after the instillation of endotoxin, but this hearing loss

T. Morizono; K. Ikeda



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.

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



Comparison of the limulus amebocyte lysate test and gas chromatography-mass spectrometry for measuring lipopolysaccharides (endotoxins) in airborne dust from poultry-processing industries.  

PubMed Central

The lipopolysaccharide (endotoxin) content in airborne dust samples from three different poultry slaughterhouses was determined with both the chromogenic Limulus amebocyte lysate assay and gas chromatography-mass spectrometry analysis of lipopolysaccharide-derived 3-hydroxy fatty acids. Gram-negative cell walls were also measured by using two-dimensional gas chromatography/electron-capture analysis of diaminopimelic acid originating from the peptidoglycan. The correlation between the results of the Limulus assay and those of gas chromatography-mass spectrometry for determination of the lipopolysaccharide content in the dust samples was poor, whereas a good correlation was obtained between lipopolysaccharide and diaminopimelic acid concentrations with the gas chromatographic methods. The results suggest that it is predominantly cell-wall-dissociated lipopolysaccharides that are measured with the Limulus assay, whereas the gas chromatographic methods allow determination of total concentrations of lipopolysaccharide, including Limulus-inactive lipopolysaccharide, gram-negative cells, and cellular debris.

Sonesson, A; Larsson, L; Schutz, A; Hagmar, L; Hallberg, T



Comparison of the limulus amebocyte lysate test and gas chromatography-mass spectrometry for measuring lipopolysaccharides (endotoxins) in airborne dust from poultry-processing industries.  


The lipopolysaccharide (endotoxin) content in airborne dust samples from three different poultry slaughterhouses was determined with both the chromogenic Limulus amebocyte lysate assay and gas chromatography-mass spectrometry analysis of lipopolysaccharide-derived 3-hydroxy fatty acids. Gram-negative cell walls were also measured by using two-dimensional gas chromatography/electron-capture analysis of diaminopimelic acid originating from the peptidoglycan. The correlation between the results of the Limulus assay and those of gas chromatography-mass spectrometry for determination of the lipopolysaccharide content in the dust samples was poor, whereas a good correlation was obtained between lipopolysaccharide and diaminopimelic acid concentrations with the gas chromatographic methods. The results suggest that it is predominantly cell-wall-dissociated lipopolysaccharides that are measured with the Limulus assay, whereas the gas chromatographic methods allow determination of total concentrations of lipopolysaccharide, including Limulus-inactive lipopolysaccharide, gram-negative cells, and cellular debris. PMID:2187411

Sonesson, A; Larsson, L; Schütz, A; Hagmar, L; Hallberg, T



Differential cytokine induction by doses of lipopolysaccharide and monophosphoryl lipid A that result in equivalent early endotoxin tolerance.  

PubMed Central

The phenomenon of early endotoxin tolerance, which is induced by sublethal injection of lipopolysaccharide (LPS), results in a protracted period of hyporesponsiveness that is most profound at 3 to 4 days after injection and is marked by reduced cytokine production after a challenge injection of LPS. Early endotoxin tolerance is also induced by the nontoxic LPS derivative monophosphoryl lipid A (MPL), although much more of the monophosphoryl derivative is required to produce a state of tolerance equivalent to that evoked by LPS. In this study, equivalent tolerance-inducing doses of LPS and MPL were tested, and the levels of cytokines induced by LPS and MPL were compared. Although induced levels of colony-stimulating factor were comparable following doses of LPS and MPL that elicited an equivalent state of early endotoxin tolerance, levels of tumor necrosis factor, interleukin-6, and interferon were significantly lower in MPL-injected animals. These results suggest that the lowered toxicity of MPL may be related to its elicitation of significantly lower levels of potentially toxic intermediaries such as tumor necrosis factor, interferon, and interleukin-6.

Henricson, B E; Benjamin, W R; Vogel, S N



A synthetic lipopolysaccharide-binding peptide based on the neutrophil-derived protein CAP37 prevents endotoxin-induced responses in conscious rats.  

PubMed Central

The lipid A component of lipopolysaccharide (LPS) derived from Escherichia coli has been implicated as a significant mediator in the development of circulatory and metabolic dysfunction and lethality associated with sepsis. A synthetic peptide corresponding to amino acid residues 20 through 44 of the neutrophil-derived 37-kDa cationic antimicrobial protein (CAP37 P(20-44)) possesses lipid A binding characteristics which may be useful in attenuating in vivo responses induced during circumstances of endotoxemia, including sepsis. The E. coli LPS to be used in the in vivo study was shown to be attenuated by CAP37 P(20-44) in a dose-dependent manner in the in vitro reaction with Limulus amoebocyte lysate. Intravenous infusion of CAP37 P(20-44) (1.5 or 3.0 mg/kg of body weight) with E. coli LPS (250 microg/kg over 30 min) into conscious, unrestrained rats prevented LPS-induced hyperdynamic and hypodynamic circulatory shock, hyperlactacidemia, and leukopenia in a dose-related fashion. CAP37 P(20-44) (0.2, 1.0, and 5.0 mg/kg) administered intravenously to conscious, actinomycin D-sensitized rats following a lethal dose of LPS neutralized LPS toxicity, resulting in dose-dependent 7-day survival rates of 30, 50, and 80%, respectively. CAP37 P(20-44) (5.0 mg/kg) significantly inhibited the endotoxin-induced increase in circulating tumor necrosis factor alpha in sensitized rats. These data demonstrate that CAP37 P(20-44) has the capacity to abolish in vivo biological responses to LPS that are relevant to human sepsis and to significantly neutralize the toxicity of circulating E. coli LPS.

Brackett, D J; Lerner, M R; Lacquement, M A; He, R; Pereira, H A



Differential responses of the endothelial and epithelial barriers of the lung in sheep to Escherichia coli endotoxin.  

PubMed Central

Although intravenous Escherichia coli endotoxin has been used extensively in experimental studies to increase lung endothelial permeability, the effect of E. coli endotoxin on lung epithelial permeability has not been well studied. To examine this issue in sheep, bidirectional movement of protein across the lung epithelial barrier was studied by labeling the vascular space with 131I-albumin and by instilling 3 ml/kg of an isosmolar protein solution with 125I-albumin into the alveoli. E. coli endotoxin was administered according to one of three protocols: intravenous alone (5-500 micrograms/kg), intravenous (5 micrograms/kg) plus low-dose alveolar endotoxin (10 micrograms/kg), and high-dose alveolar endotoxin alone (50-100 micrograms/kg). Alveolar liquid clearance was estimated based on the concentration of the instilled native protein. Sheep were studied for either 4 or 24 h. Although intravenous E. coli endotoxin produced a marked increase in transvascular protein flux and interstitial pulmonary edema, there was no effect on the clearance of either the vascular (131I-albumin) or the alveolar (125I-albumin) protein tracer across the epithelial barrier. High-dose alveolar E. coli endotoxin caused a 10-fold increase in the number of leukocytes, particularly neutrophils, that accumulated in the air spaces. In spite of the marked chemotactic effect of alveolar endotoxin, there was no change in the permeability of the epithelial barrier to the vascular or alveolar protein tracers. Also, alveolar epithelial liquid clearance was normal. Morphologic studies confirmed that the alveolar epithelial barrier was not injured by either intravenous or alveolar E. coli endotoxin. Thus, the alveolar epithelium in sheep is significantly more resistant than the lung endothelium to the injurious effects of E. coli endotoxin. Images

Wiener-Kronish, J P; Albertine, K H; Matthay, M A



Clinical and clinico-pathological effects of Escherichia coli endotoxin in mature cattle.  

PubMed Central

The effects of intravenous administration of Escherichia coli endotoxin were studied in eight mature lactating cows. Three cows were studied following intrammary infection with E. coli. Significant clinical findings are presented. Significant clinico-pathological findings include leukopenia, decreased blood serum calcium concentrations and increased levels of serum glutamic-oxaloacetic transaminase and serum ornithine-carbamyl transferase. Significant elevations of plasma corticosteroids were also noted.

Griel, L C; Zarkower, A; Eberhart, R J



Effect of enrofloxacin treatment on plasma endotoxin during bovine Escherichia coli mastitis  

Microsoft Academic Search

Objective and design: To investigate the effect of enrofloxacin on endotoxin resorption during bovine Escherichia coli mastitis. Animals: 12 healthy early post partum Holstein cows. Treatment: Mastitis was induced by intramammary infusion of 10 4 cfu E. coli P4:O32. Six cows were treated twice according to the usual enrofloxacin therapy: 5 mg\\/kg enro- floxacin 1) intravenously at 10 h and

H. Dosogne; E. Meyer; A. Sturk; J. van Loon; A. M. Massart-Leën; C. Burvenich



Effectiveness of castor oil extract on Escherichia coli and its endotoxins in root canals.  


This in vitro study sought to evaluate the effectiveness of castor oil extract used as an irrigating solution on Escherichia coli and its endotoxins in root canals. Sixty single-rooted teeth were prepared (using castor oil extract as irrigating solution) and divided into five groups (n = 12): Group 1 samples were treated with calcium hydroxide (Ca(OH)2), Group 2 samples were treated with polymyxin B, Group 3 samples were treated with Ca(OH)2 and 2% chlorhexidine gel (CHX), and Group 4 samples were treated with castor oil extract. A control group used physiological saline solution as an irrigant. Canal content samples were collected at four different times: immediately after instrumentation, seven days after instrumentation, after 14 days of intracanal medication, and seven days after removal of intracanal medication. A plating method was used to assess antimicrobial activity and the quantification of endotoxins was evaluated by the chromogenic Limulus lysate assay. Data were submitted to ANOVA and a Dunn test (a = 5%). Irrigation with castor oil extract decreased E. coli counts but had no effect on the level of endotoxins. Samples taken seven days after removal of medication revealed a significant reduction in endotoxin levels in Groups 3 and 4. Compared to the saline solution irrigation, castor oil extract decreased microorganism counts in root canals immediately after canal preparation. None of the medications used completely eliminated endotoxins in the root canal. PMID:22782052

Valera, Marcia Carneiro; Maekawa, Lilian Eiko; Chung, Adriana; de Oliveira, Luciane Dias; Carvalho, Claudio Antonio Talge; Koga-Ito, Cristiane Yumi; Jorge, Antonio Olavo Cardoso


Endotoxin affinity for orthodontic brackets.  


Endotoxin, cell envelope lipopolysaccharide produced by gram-negative bacteria can activate an immune response through a variety of pathways. In addition, it can stimulate bone resorption and reduce the periodontal tissue's healing capacity. Previous studies have documented the affinity of lipopolysaccharide for restorative materials. This study evaluated the affinity of lipopolysaccharide for commercially available orthodontic brackets. Stainless steel, ceramic, plastic, and "gold" brackets were exposed to 10 EU/mm2radiolabeled Porphyromonas gingivalis or Escherichia coli lipolpoysaccharide in water and incubated for 24 hours at 37 degrees C. Brackets were then transferred to fresh lipopolysaccharide-free water and incubated for 24 hours at 37 degrees C to evaluate elution. This elution transfer was continued up to 96 hours total incubation. Lipopolysaccharide adherence and elution levels were calculated after treatment, and elution solutions were evaluated through liquid scintillation spectrometry. Mean initial lipopolysaccharide adherence ranged from 2.42 +/- 0.26 EU/mm2(E. coli, plastic) to 6.75 +/- 0.34 EU/mm2 (P. gingivalis, stainless steel). P. gingivalis lipopolysaccharide adherence was significantly greater than E. coli lipopolysaccharide adherence for all bracket types. Moreover, for each lipopolysaccharide type, stainless steel brackets exhibited significantly greater lipopolysaccharide adherence. Regarding elution, only the P. gingivalis lipopolysaccharide-exposed ceramic and plastic brackets at 24 hours and the stainless steel and ceramic brackets at 48 hours eluted measurable lipopolysaccharide. Results from this study demonstrate that P. gingivalis and E. coli LPS exhibit a high affinity for orthodontic brackets. In vivo, this affinity could affect the concentration of LPS in the gingival sulcus, thereby contributing to inflammation in tissues adjacent to the brackets. PMID:10358245

Knoernschild, K L; Rogers, H M; Lefebvre, C A; Fortson, W M; Schuster, G S



Pulmonary toxicity of endotoxins: comparison of lipopolysaccharides from various bacterial species.  


Lipopolysaccharides from three gram-negative bacteria isolated from bale cotton and piggery air were analyzed for their chemical composition, and their pulmonary toxicity for guinea pigs, lethal toxicity for mice, and pyrogenicity for rabbits were measured. Lipopolysaccharides from Enterobacter agglomerans and Citrobacter freundii had closely related chemical compositions; both were pyrogenic for rabbits and caused a dose-dependent influx of polymorphonuclear leukocytes into the airways of guinea pigs. The lethal toxicities of these lipopolysaccharides in mice were comparable to that of Salmonella typhimurium lipopolysaccharide, which was used as a reference. Lipopolysaccharide from Agrobacterium sp. was chemically different from those of E. agglomerans and C. freundii, did not induce any influx of polymorphonuclear leukocytes, and was only weakly toxic or pyrogenic. The low biological activity of the agrobacterial lipopolysaccharide may be due to its different chemical composition. PMID:7056574

Helander, I; Saxén, H; Salkinoja-Salonen, M; Rylander, R



Increased antibacterial activity against Escherichia coli in bovine serum after the induction of endotoxin tolerance.  

PubMed Central

Small amounts of endotoxin injected intramuscularly into cows induced endotoxin pyrogenic tolerance and an increase in the rate at which the serum killed a strain of Escherichia coli. Most of the difference between normal serum and serum from the endotoxin-tolerant animal was shown to be due to a bentonite-adsorbable factor other than lysozyme or beta-lysin. The antibacterial activity was not completely removed from either type of serum after bentonite adsorption. Electron microscope studies and measurement of the rate of release of radioactively labeled cytoplasmic contents showed that the bentonite-adsorbable factor was important in the final breakdown of the cell membrane and release of cellular contents. The antibacterial system was totally dependent on complement, and the importance of antibodies could not be entirely ruled out because adsorption at O C with homologous cells eliminated the killing activity. Images

Hill, A W; Shears, A L; Hibbitt, K G



Lipopolysaccharide structure required for in vitro trimerization of Escherichia coli OmpF porin.  

PubMed Central

Deep rought mutants, which produce very defective lipopolysaccharides, are unable to export normal levels of porins into the outer membrane. In this study, we showed that lipopolysaccharides from such mutants were also unable to facilitate the trimerization, in vitro, of monomeric OmpF porin secreted by spheroplasts of Escherichia coli B/r. In contrast, lipopolysaccharides containing most or all of the core oligosaccharides were able to facilitate trimerization. Images

Sen, K; Nikaido, H



Role of Lipopolysaccharide and Capsule in the Serum Resistance of Bacteremic Strains of 'Escherichia coli'.  

National Technical Information Service (NTIS)

To define the relative roles of capsule and lipopolysaccharide in the virulence of Escherichia coli obtained from blood, the authors compared the behavior of K1-and K5-encapsulated strains in serum bactericidal and rat virulence assays. Unencapsulated iso...

A. S. Cross K. S. Kim D. C. Wright J. C. Sadoff P. Gemski



Endotoxin of Escherichia coli and permeability of the mammary glands of goats  

SciTech Connect

Serial collections of milk were used to determine where in the mammary gland endotoxin of Escherichia coli was effective in altering the transfer of selected milk components into blood and blood components into milk. Lactating goats had half the gland infused with 1 of endotoxin and the other half served as a control. Sodium-24 and /sup 42/K or (/sup 14/C) lactose were included with /sup 141/Ce in the infusate in some experiments, whereas in others /sup 99m/Tc-labelled albumin or /sup 24/Na and /sup 42/K were given intravenously 2 h after the endotoxin infusion. Milk was collected 3 h after endotoxin infusion. Endotoxin increased the loss of /sup 24/Na, /sup 42/K, and (/sup 14/C) lactose from the mammary gland and increased the transfer of /sup 24/Na and /sup 99m/Tc-albumin into the gland. The transfer in of /sup 42/K was reduced compared with control halves. Movement of stable Na and K was in accord with the movement of the /sup 24/Na and /sup 42/K. Endotoxin was effective in all parts of the gland but particularly from the mid-portion upward to the alveoli. For the control halves there was evidence that some /sup 24/Na and /sup 42/K crossed the ductal or cisternal epithelium into blood outside of the alveoli, whereas only /sup 42/K provided evidence for transfer from blood to milk in these same regions. There was no demonstrable transfer of lactose and albumin in regions other than the alveoli.

Lengemann, F.W.; Pitzrick, M.



Oral administration of Saccharomyces cerevisiae boulardii reduces Escherichia coli endotoxin associated mortality in weaned pigs  

Technology Transfer Automated Retrieval System (TEKTRAN)

The effects of active dry yeast, Saccharomyces cerevisiae boulardii (Scb), on the immune/neuroendocrine response and subsequent mortality to E. coli lipopolysaccharide (LPS) administration were evaluated in newly weaned pigs (26.1 + or - 3.4 d of age). Barrows were assigned to 1 of 2 treatment group...


Baicalin inhibits macrophage activation by lipopolysaccharide and protects mice from endotoxin shock  

Microsoft Academic Search

Baicalin (BA) exhibits anti-inflammatory effect in vivo and in vitro and is used to treat inflammatory diseases. Here, we report that BA inhibits the activation of macrophage and protects mice from macrophage-mediated endotoxin shock. The experiments in vitro showed BA suppressed the increased generation of nitric oxide (NO) and expression of inducible nitric oxide synthase (iNOS) induced by LPS or

Lin-lin Liu; Li-kun Gong; Hui Wang; Ying Xiao; Xiong-fei Wu; Yun-hai Zhang; Xiang Xue; Xin-ming Qi; Jin Ren



Lipopolysaccharide (Endotoxin)-host defense antibacterial peptides interactions: Role in bacterial resistance and prevention of sepsis  

Microsoft Academic Search

Lipopolysaccharide (LPS) is the major molecular component of the outer membrane of Gram-negative bacteria and serves as a physical barrier providing the bacteria protection from its surroundings. LPS is also recognized by the immune system as a marker for the detection of bacterial pathogen invasion, responsible for the development of inflammatory response, and in extreme cases to endotoxic shock. Because

Yosef Rosenfeld; Yechiel Shai



Interaction of Bacterial Endotoxine (Lipopolysaccharide) with Latex Particles: Application to Latex Agglutination Immunoassays  

Microsoft Academic Search

The latex agglutination immunoassay technique uses polymer colloids as carriers for antibodies or antigens to enhance the immunological reaction. In this work, the interaction of a lipopolysaccharide (LPS) of Brucella Melitensis with two conventional latexes has been studied. Some experiments on the physical adsorption of the LPS onto these polystyrene beads have been performed and several complexes with different coverage

J. M. Peula-Garc??a; J. A. Molina-Bolivar; J. Velasco; A. Rojas; F. Galisteo-González



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



Central role for type I interferons and Tyk2 in lipopolysaccharide-induced endotoxin shock  

Microsoft Academic Search

Toll-like receptor-4 activation by lipopolysaccharide (LPS) induces the expression of interferon-? (IFN-?) in a MyD88-independent manner. Here we report that mice devoid of the JAK protein tyrosine kinase family member, Tyk2, were resistant to shock induced by high doses of LPS. Basal and LPS-induced expression of IFN-? and IFN-?4 mRNA in Tyk2-null macrophages were diminished. However, Tyk2-null mice showed normal

Marina Karaghiosoff; Ralf Steinborn; Pavel Kovarik; Gernot Kriegshäuser; Manuela Baccarini; Birgit Donabauer; Ursula Reichart; Thomas Kolbe; Christian Bogdan; Tomas Leanderson; David Levy; Thomas Decker; Mathias Müller



The influence of sanitizers on the lipopolysaccharide composition of Escherichia coli O111.  


This study focused on the influence of typical sanitizers on the composition of the lipopolysaccharides (LPS) produced by the verocytotoxin-producing (VTEC) Escherichia coli O111. We also aimed to cast light on the applicability of O-antigen-based serotyping and endotoxin based Limulus Amebocyte Lysate (LAL) assays applied in the food industry for the identification and quantification of Gram-negative bacteria. E. coli O111 was propagated in the presence of three typical commercially applied sanitizing solutions that included a Clean in Place (CIP) chlorinated sanitizer (bacteriocidal), heavy-duty alkaline sanitizer (bacteriocidal) and a phenolic hand wash solution (bacteriostatic). After the required growth phase was reached the LPS from both the intact cells and debris was extracted and methanolysed followed by trifluoroacetylation. Subsequently GC-MS analysis and the chromogenic LAL assay were applied to assess both the ultra-structure and the toxicity of the extracted LPS. The viability and debris formation during growth was also evaluated to verify the bacteriocidial and static effect of the applied sanitizers as well as to assess its relationship with LPS formation. The total LPS produced was quantified at 1.3 x 10(6) [KDO] x OD(620 nm)(-1) for the control samples, 6.5 x 10(3) [KDO] x OD(620 nm)(-1) for E. coli grown in the presence of CIP chlorinated sanitizer and 2.1 x 10(5) and 2.85 x 10(6) [KDO] x OD(620 nm)(-1) for the organisms grown in the presence of heavy-duty alkaline sanitizer and phenolic hand wash solution respectively (KDO = 2-keto-3-deoxy-octulosonic acid). A negative correlation (gamma(2)= -0.880) between the [KDO] and Delta viability was evident and indicated that E. coli O111 responds to factors that hinder viability by producing more LPS in its outer membrane. Subsequent assessment of the LPS ultra-structure revealed a definite change in both the total assessed saccharide and lipid fractions. The cumulative change of the LPS in response to the sanitizers further appeared to influence the toxicity of the LPS as the latter change could not be related to an individual compound within any of the assessed fractions. This emphasised the fact that the quantity of LPS obtained from E. coli O111 in this study, did not seem to determine the toxicity of the organism. From the results we further propose a coefficient that could be applied to describe the response of E. coli O111 LPS to sanitizers and caution against the application of serotyping (based on the O-antigen) and the LAL assay to quantify and identify E. coli O111 obtained from food strata where the possibility of sanitizer contamination exists. PMID:16859796

Venter, P; Abraham, M; Lues, J F R; Ivanov, I



Effect of Jianpi Huoxue decoction (?????)-containing serum on tumor necrosis factor-? secretion and gene Expression of endotoxin receptors in RAW264.7 cells induced by lipopolysaccharide  

Microsoft Academic Search

Objective  To evaluate the effect of Jianpi Huoxue decoction (?????, JHD)-containing serum on tumor necrosis factor-? (TNF-?) secretion\\u000a and endotoxin receptor gene expression in RAW264.7 cells induced by lipopolysaccharide (LPS).\\u000a \\u000a \\u000a \\u000a Methods  The cytotoxicity of blank-control serum and JHD-containing serum at different concentrations were evaluated through the lactate\\u000a dehydrogenase (LDH) assay in RAW264.7 cells. RAW264.7 cells were divided into six groups: 5% blank-control

Jing-hua Peng; Yi-yang Hu; Qin Feng; Yang Cheng; Li-li Xu; Shao-dong Chen; Qing Tao; Feng-hua Li



Cytoplasmic ATP Hydrolysis Powers Transport of Lipopolysaccharide Across the Periplasm in E. coli*  

PubMed Central

Millions of molecules of lipopolysaccharide (LPS) must be assembled on the E. coli cell surface every division. Biogenesis of LPS requires seven essential lipopolysaccharide transport (Lpt) proteins to move LPS from the inner membrane (IM) through the periplasm to the cell surface. However, no intermediate transport states have been observed. We developed methods to observe intermediate LPS molecules bound to Lpt proteins in the process of being transported in vivo. Movement of individual LPS molecules along these binding sites required multiple rounds of ATP hydrolysis in vitro, which suggests that ATP is used to push a continuous stream of LPS through a transenvelope bridge in discrete steps against a concentration gradient.

Okuda, Suguru; Freinkman, Elizaveta; Kahne, Daniel



Attenuation by intravenous 2-chloroadenosine of acute lung injury induced by live escherichia coli or latex particles added to endotoxin in the neutropenic state  

Microsoft Academic Search

Although neutrophil depletion can reduce the level of acute lung injury (ALI) induced by Escherichia coli endotoxin, that induced by live E coli cannot be attenuated even in neutropenia. This suggests that live E coli cause ALI by way of an mechanism independent of circulating neutrophil. Tumor necrosis factor-? (TNF-?), which is released from monocytes and macrophages, is a proinflammatory

Fumio Sakamaki; Akitoshi Ishizaka; Tetsuya Urano; Koichi Sayama; Hidetoshi Nakamura; Takeshi Terashima; Yasuhiro Waki; Kenzo Soejima; Sadatomo Tasaka; Makoto Sawafuji; Kouichi Kobayashi; Kazuhiro Yamaguchi; Minoru Kanazawa



Control of endotoxin activity and interleukin-1 production through regulation of lipopolysaccharide-lipoprotein binding by a macrophage factor.  

PubMed Central

Lipopolysaccharides (LPSs) extracted from gram-negative bacteria are much less active when bound to serum lipoproteins. We present evidence here that the binding of radiolabeled LPS extracted from Escherichia coli O113 and Salmonella typhimurium to lipoproteins in rabbit serum is increased 8 to 24 h after a single intravenous injection of homologous or heterologous LPS. Supernatants of activated macrophages containing interleukin-1 also stimulate increased binding. The isolated product of this binding does not induce the production of interleukin-1 by macrophages in vivo or in vitro and is unable itself to stimulate increased binding of LPS to lipoprotein. Normal rabbit sera spiked with lipoprotein fractions prepared from tolerant but not normal rabbit sera bind increased amounts of LPS. These data suggest that there may exist a self-regulated mechanism for decreasing the toxicity of LPS and the production of LPS-induced interleukin-1; this mechanism is controlled by a macrophage factor and functions through altering the binding of LPS to certain serum lipoproteins.

Warren, H S; Riveau, G R; de Deckker, F A; Chedid, L A



The influence of prazosin on E. coli lipopolysaccharide-induced fever and noradrenaline hyperthermia.  


We investigated the effect of prazosin on experimental fever induced by E. coli lipopolysaccharide (LPS) and on noradrenaline hyperthermia in the rabbit. LPS and prazosin were administered iv and ivc, noradrenaline was administered only iv. Prazosin inhibited both LPS fever and noradrenaline hyperthermia in a dose-dependent manner. The results indicate the participation of alpha-adrenoceptor in the pyrogen fever and noradrenaline hyperthermia. PMID:6398869

Matuszek, M; Szreder, Z


Enhanced susceptibility to lipopolysaccharide-induced arthritis and endotoxin shock in interleukin-32 alpha transgenic mice through induction of tumor necrosis factor alpha  

PubMed Central

Introduction The present study assessed the potential functions of interleukin (IL)-32? on inflammatory arthritis and endotoxin shock models using IL-32? transgenic (Tg) mice. The potential signaling pathway for the IL-32-tumor necrosis factor (TNF)? axis was analyzed in vitro. Methods IL-32? Tg mice were generated under control of a ubiquitous promoter. Two disease models were used to examine in vivo effects of overexpressed IL-32?: Toll-like receptor (TLR) ligand-induced arthritis developed using a single injection of lipopolysaccharide (LPS) or zymosan into the knee joints; and endotoxin shock induced with intraperitoneal injection of LPS and D-galactosamine. TNF? antagonist etanercept was administered simultaneously with LPS in some mice. Using RAW264.7 cells, in vitro effects of exogenous IL-32? on TNF?, IL-6 or macrophage inflammatory protein 2 (MIP-2) production were assessed with or without inhibitors for nuclear factor kappa B (NF?B) or mitogen-activated protein kinase (MAPK). Results Single injection of LPS, but not zymosan, resulted in development of severe synovitis with substantial articular cartilage degradation in knees of the Tg mice. The expression of TNF? mRNA in inflamed synovia was highly upregulated in the LPS-injected Tg mice. Moreover, the Tg mice were more susceptive to endotoxin-induced lethality than the wild-type control mice 48 hours after LPS challenge; but blockade of TNF? by etanercept protected from endotoxin lethality. In cultured bone marrow cells derived from the Tg mice, overexpressed IL-32? accelerated production of TNF? upon stimulation with LPS. Of note, exogenously added IL-32? alone stimulated RAW264.7 cells to express TNF?, IL-6, and MIP-2 mRNAs. Particularly, IL-32? -induced TNF?, but not IL-6 or MIP-2, was inhibited by dehydroxymethylepoxyquinomicin (DHMEQ) and U0126, which are specific inhibitors of nuclear factor kappa B (NF?B) and extracellular signal regulated kinase1/2 (ERK1/2), respectively. Conclusions These results show that IL-32? contributed to the development of inflammatory arthritis and endotoxin lethality. Stimulation of TLR signaling with LPS appeared indispensable for activating the IL-32?-TNF? axis in vivo. However, IL-32? alone induced TNF? production in RAW264.7 cells through phosphorylation of inhibitor kappa B (I?B) and ERK1/2 MAPK. Further studies on the potential involvement of IL-32?-TNF? axis will be beneficial in better understanding the pathology of autoimmune-related arthritis and infectious immunity.



Oral administration of Saccharomyces cerevisiae boulardii reduces mortality associated with immune and cortisol responses to Escherichia coli endotoxin in pigs.  


The effects of active dry yeast, Saccharomyces cerevisiae boulardii (Scb), on the immune/cortisol response and subsequent mortality to Escherichia coli lipopolysaccharide (LPS) administration were evaluated in newly weaned piglets (26.1 ± 3.4 d of age). Barrows were assigned to 1 of 2 treatment groups: with (Scb; n = 15) and without (control; n = 15) the in-feed inclusion of Scb (200 g/t) for 16 d. On d 16, all piglets were dosed via indwelling jugular catheters with LPS (25 ?g/kg of BW) at 0 h. Serial blood samples were collected at 30-min intervals from -1 to 6 h and then at 24 h. Differential blood cell populations were enumerated hourly from 0 to 6 h and at 24 h. Serum cortisol, IL-1?, IL-6, tumor necrosis factor-? (TNF-?), and interferon-? (IFN-?) concentrations were determined via porcine-specific ELISA at all time points. In Scb-treated piglets, cumulative ADG increased (P < 0.05) by 39.9% and LPS-induced piglet mortality was reduced 20% compared with control piglets. White blood cells, lymphocytes, and neutrophils were increased (P < 0.05) in Scb-treated animals before LPS dosing compared with control piglets before being equally suppressed (P < 0.05) from baseline in both treatments after LPS dosing with a return to baseline by 24 h. Suppression of circulating cortisol concentrations (P < 0.05) was observed in Scb-treated piglets from -1 h to 1 h relative to LPS dosing compared with control animals before both peaked equally and subsequently returned to baseline. Peak production (P < 0.05) of IL-1? and IL-6 was less in Scb-treated piglets after LPS administration compared with controls before both equally returned to baseline. Peak TNF-? production in Scb-treated animals was accelerated 0.5 h and was greater (P < 0.05) than peak production in control piglets, after which both equally returned to baseline. The peak production of IFN-? was greater and had increased (P < 0.05) amplitude persistence for 3 h in Scb-treated animals compared with control piglets before both equally returned to baseline. These results highlight the previously unidentified effects of Scb administration on immune and cortisol responses and the subsequent impact on growth and endotoxin-induced mortality in weaned piglets. PMID:20852076

Collier, C T; Carroll, J A; Ballou, M A; Starkey, J D; Sparks, J C



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.



[Ultrastructural alterations in rat brain tissues under the direct action of Escherichia coli endotoxin].  


The experiments on the rats with intracisternal injection of endotoxin have revealed essential differences in the mechanisms of its permeability through cerebrospinal fluid-brain and blood-cerebrospinal fluid barriers. As for ependymal cells, endotoxin shunts through the cytoplasm in the areas of tight junctions and then it reaches perineuronal spaces. The mechanism of endotoxin penetration through the epithelium of choroid plexi is associated with receptor-mediated endocytosis. PMID:1790815

Bardakhch'ian, E A; Kharlanova, N G


Extract of Alpinia officinarum Suppresses Enteropathogenic Escherichia coli (EPEC) Lipopolysaccharide (LPS) Induced Inflammation in J774 A.1 Macrophages  

Microsoft Academic Search

Molecules with bi-functional activities are pre- ferred targets in drug discovery research today. In this study, a possible dual role (anti-inflammatory and anti-bacterial activity) of a plant extract has been discussed. As an initiative, the extract is found to sup- press inflammation caused by endotoxin release from an enteric pathogen. Enteropathogenic Escherichia coli (E. coli )( EPEC O127:H6) causes persistent

Krishnan Subramanian; Chinnasamy Selvakkumar; Sankaranarayanan Meenakshisundaram; Arun Balakrishnan; Baddireddi Subhadra Lakshmi



Endotoxin affinity for orthodontic brackets  

Microsoft Academic Search

Endotoxin, cell envelope lipopolysaccharide produced by gram-negative bacteria can activate an immune response through a variety of pathways. In addition, it can stimulate bone resorption and reduce the periodontal tissue’s healing capacity. Previous studies have documented the affinity of lipopolysaccharide for restorative materials. This study evaluated the affinity of lipopolysaccharide for commercially available orthodontic brackets. Stainless steel, ceramic, plastic, and

Kent L. Knoernschild; Holly M. Rogers; Carol A. Lefebvre; Weston M. Fortson; George S. Schuster



Etanercept treatment in the endotoxin-induced uveitis of rats  

Microsoft Academic Search

This study was conducted to investigate therapeutic value of a soluble tumor necrosis factor-? (TNF-?) receptor, etanercept, in a rat model of endotoxin-induced uveitis (EIU). Forty-two inbred male Lewis rats were divided into seven equal groups. 200 ?g of Escherichia coli 055:B55 lipopolysaccharide (LPS) was injected in one hind footpad of the Groups 2, 3, 4, 5, 6, and 7

Mustafa Cihat Avunduk; Avni Murat Avunduk; Esma Oztekin; Abdülkerim Kasim Baltaci; Yilmaz Ozyazgan; Rasim Mogolkoc



Production and characterization of monoclonal antibodies specific for the lipopolysaccharide of Escherichia coli O157.  

PubMed Central

Identification of the O157 antigen is an essential part of the detection of Escherichia coli O157:H7, which is recognized as a major etiologic agent of hemorrhagic colitis. However, polyclonal antibodies produced against E. coli O157:H7 lipopolysaccharide (LPS) may react with several other bacteria including Brucella abortus, Brucella melitensis, Yersinia enterocolitica O9, Escherichia hermannii, and Stenotrophomonas maltophilia. We produced eight monoclonal antibodies (MAbs) specific for the LPS of E. coli O157. Western blots (immunoblots) of both the phenol phase (smooth) and the aqueous phase (rough) of hot phenol-water-purified LPS indicated that three of the MAbs were specific for the O antigen and five were reactive with the LPS core. The eight MAbs could be further differentiated by their reactivities to Salmonella O30 LPS (group N), which is reported to be identical to the E. coli O157 antigen. All eight MAbs reacted strongly to all of the 64 strains of E. coli O157 tested, which included 47 isolates of O157:H7 and 17 other O157 strains. None of the eight MAbs cross-reacted with any of the 38 other E. coli serotypes tested, which consisted of 29 different O-antigen serotypes, or with 38 strains (22 genera) of non-E. coli gram-negative enteric bacteria.

Westerman, R B; He, Y; Keen, J E; Littledike, E T; Kwang, J



Production and characterization of monoclonal antibodies specific for the lipopolysaccharide of Escherichia coli O157.  


Identification of the O157 antigen is an essential part of the detection of Escherichia coli O157:H7, which is recognized as a major etiologic agent of hemorrhagic colitis. However, polyclonal antibodies produced against E. coli O157:H7 lipopolysaccharide (LPS) may react with several other bacteria including Brucella abortus, Brucella melitensis, Yersinia enterocolitica O9, Escherichia hermannii, and Stenotrophomonas maltophilia. We produced eight monoclonal antibodies (MAbs) specific for the LPS of E. coli O157. Western blots (immunoblots) of both the phenol phase (smooth) and the aqueous phase (rough) of hot phenol-water-purified LPS indicated that three of the MAbs were specific for the O antigen and five were reactive with the LPS core. The eight MAbs could be further differentiated by their reactivities to Salmonella O30 LPS (group N), which is reported to be identical to the E. coli O157 antigen. All eight MAbs reacted strongly to all of the 64 strains of E. coli O157 tested, which included 47 isolates of O157:H7 and 17 other O157 strains. None of the eight MAbs cross-reacted with any of the 38 other E. coli serotypes tested, which consisted of 29 different O-antigen serotypes, or with 38 strains (22 genera) of non-E. coli gram-negative enteric bacteria. PMID:9041412

Westerman, R B; He, Y; Keen, J E; Littledike, E T; Kwang, J



Increased Levels of LPS-Binding Protein in Bovine Blood and Milk Following Bacterial Lipopolysaccharide Challenge  

Microsoft Academic Search

Several species of gram-negative bacteria, including Escherichia coli, Klebsiella pneumoniae, and various species of Enterobacter, are common mastitis patho- gens. Allof thesebacteria arecharacterized bythe pres- ence of endotoxin or lipopolysaccharide (LPS) in their outer membrane. The bovine mammary gland is highly sensitive to LPS, and LPS has been implicated, in part, in the pathogenesis of gram-negative mastitis. Recogni- tion of

Douglas D. Bannerman; Max J. Paape; William R. Hare; Eun Jung Sohn



Inhibition of 3-O-Methyl Glucose Transport in 'Ascaris suum' Midgut by 'Escherichia coli' Endotoxin.  

National Technical Information Service (NTIS)

Movement of 3-0-methyl glucose across the midgut of Ascaris was inhibited by endotoxin. Inhibition was dependent on endotoxin concentration. Despite the fact that the mechanism by which the transport is inhibited is not known, the knowledge that absorptiv...

J. H. Migliaccio



Silica enhancement of murine endotoxin sensitivity.  

PubMed Central

Silica has been used for many years as an agent which selectively alters macrophage functions and, as such, has been used to assess the role of macrophages in the immune response to a variety of microbial and chemically defined agents. Silica treatment of C3H/HeN mice 1 day before challenge with protein-free Escherichia coli endotoxin (lipopolysaccharide [LPS]) resulted in a marked increase in LPS sensitivity, as evidenced by accelerated signs of endotoxemia as well as a fourfold decrease in the LPS 50% lethal dose. The silica-mediated increase in responsiveness to LPS was associated with increased production of macrophage-derived soluble factors both in vivo (interferon) and in vitro (Interleukin 1; previously referred to as lymphocyte activating factor or LAF) upon endotoxin stimulation. These findings support the central role of the macrophage and its products in mediating endotoxic reactions.

Vogel, S N; English, K E; O'Brien, A D



Antibody Responses to Escherichia coli O157 and Other Lipopolysaccharides in Healthy Children and Adults  

PubMed Central

In Mexico, diarrheal disease due to different serotypes of Escherichia coli is highly prevalent, with only sporadic isolation of O157 non-H7 strains. This could be due to exposure to the O157 or related E. coli lipopolysaccharide (LPS), such as O7 or O116, at an early age. By using enzyme-linked immunosorbent assay (ELISA) and Western blotting, the present study analyzed 605 serum samples from Mexican adults and infants without clinical symptoms of disease for the presence of antibodies to these three E. coli LPSs. The bactericidal activities of homologous and heterologous rabbit and human serum samples against O7, O116, and O157 E. coli LPSs were also determined. By using a cutoff point of 0.7, it was found by the ELISAs that 28 of 562 (5%) of the serum samples from adolescents and adults and 2 of 43 (5%) of the serum samples from infants less than 1 year of age reacted with the O157 LPS. By using cutoff points between 0.4 and 0.699, the proportion of serum samples from both age groups that reacted with the O157 LPS increased to 20%. Western blotting analysis of selected serum samples that showed an intermediate response against the O157 LPS by the ELISAs showed that 61 of 88 (69%) reacted with the same LPS. A similar result was observed for maternal milk samples. The bactericidal activities of rabbit serum samples against the O7, O116, and O157 LPSs showed that they were positive for both homologous and heterologous antigens. Similar results were observed with the human serum samples. O157 non-H7 strains were identified in only 10% of the E. coli strains isolated from 263 Mexican children with and without diarrhea over the past 15 years. This absence of O157:H7 strains in Mexico may be associated with the presence of antibodies against O157 or related E. coli LPSs.

Navarro, Armando; Eslava, Carlos; Hernandez, Ulises; Navarro-Henze, Jose Luis; Aviles, Magali; Garcia-de la Torre, Guadalupe; Cravioto, Alejandro




PubMed Central

There exists an inverse proportionality between number of heat-killed cells of Salmonella typhimurium injected intraperitoneally into mice and the quantity of urinary nitrogen the animals excrete during a 17 hour period following the subcutaneous administration of 2 units of ACTH. This relationship has been developed into an assay for bacterial endotoxin. Mice immunized against S. typhimurium require 10 to 20 times the number of cells needed by control animals to suppress urinary nitrogen excretion to the same extent. Intravenous saccharated iron oxide sensitizes animals so that fewer heat-killed salmonellae can be detected. Heat-killed cells of Staphylococcus aureus are without effect in the assay. Several lipopolysaccharides derived from Gram-negative bacteria are effective in preventing the rise of urinary nitrogen excreted in response to ACTH and the amount required, compared to the LD50, is in the same ratio for all of them. Citrated mouse serum partially inactivates the endotoxin during in vitro incubation for 1 hour at 37°C. while normal serum does not. Dichloroisoproterenol protects mice against the lethal effects of lipopolysaccharide and it lowers its effectiveness in the assay. The minimum amount of endotoxin reliably determined by the test is 0.25 µg. of an E. coli preparation that was given intravenously in mice in which the reticuloendothelial system had been "blocked" with saccharated iron oxide.

Berry, L. Joe; Smythe, Dorothy S.



Lipopolysaccharide pretreatment of the udder protects against experimental Escherichia coli mastitis.  


Exposure to pathogen-associated molecular patterns such as LPS can cause an immune refractory state in mammals known as endotoxin tolerance (ET), resulting in a decreased inflammatory response after pathogen contact. This ET concept was used to reduce the severity of an experimentally-induced clinical mastitis. Cows were pretreated with 1?µg LPS per udder quarter and challenged 72?h (group L72EC) or 240?h (group L240EC) later with 500 CFU Escherichia coli. Pretreated animals showed no leukopenia after challenge, no (L72EC), or only slightly (L240EC), elevated body temperature and significantly reduced systemic and local clinical scores compared with cows that were not pretreated. Whereas an increase of milk somatic cell count after the E. coli challenge was abrogated in L72EC animals, it was significantly delayed in the L240EC group. In both pretreated groups the bacterial load in milk was markedly reduced. Based on the expression of inflammation-related genes in lobulo-alveolar mammary tissue, the tolerizing effect of LPS pretreatment is based on the inhibited up-regulation of inflammatory (TNF-?, IL-6, CXCL8, CCL20) and anti-inflammatory genes (IL-10, IRAK-M). These findings indicate that the concept of ET may be usefully applied as mastitis prophylaxis facilitating a rapid response to microbial infection and avoiding dysregulated inflammation. PMID:21990573

Petzl, Wolfram; Günther, Juliane; Pfister, Tobias; Sauter-Louis, Carola; Goetze, Leopold; von Aulock, Sonja; Hafner-Marx, Angela; Schuberth, Hans-Joachim; Seyfert, Hans-Martin; Zerbe, Holm



Preliminary Characterization of the Transcriptional Response of the Porcine Intestinal Cell Line IPEC-J2 to Enterotoxigenic Escherichia coli, Escherichia coli, and E. coli Lipopolysaccharide  

PubMed Central

IPEC-J2, a promising in vitro model system, is not well characterized especially on the transcriptional level, in contrast to human counterparts. The aim of this study was to characterize the gene expression in IPEC-J2 cells when coincubated with enterotoxigenic Escherichia coli (ETEC), nonpathogenic E. coli, and E. coli endotoxin. Apical infection of polarized IPEC-J2 monolayers caused a time-dependent decrease in transepithelial electrical resistance (TEER). Microarray analysis showed up-regulation of interleukins when IPEC-J2 were cocultured with E. coli strains this has so far never been measured in this cell line. Highest IL8 expression was found with the ETEC strain possessing the F4 fimbrium, suggesting IPEC-J2 cells to be F4 receptor positive, confirmed in a brush border membrane adhesion assay. It is concluded that the innate immune responses to pathogens and LPS makes the IPEC-J2 cell line a suitable model for research on intestinal host pathogen interaction.

Geens, Marisa M.; Niewold, Theo A.



Comparison of inflammatory responses in human cells caused by lipopolysaccharides from Escherichia coli and from indigenous bacteria in aquatic environment  

Microsoft Academic Search

The endotoxic activities of lipopolysaccharides (LPSs) in water samples are usually determined using a Limulus amoebocyte lysate (LAL) assay, but it is known that the determined activities do not always represent their inflammatory potency in humans. In this investigation, the inflammatory responses in three different human cells stimulated with Escherichia coli LPS, keratinocyte, CD14 monocyte, and THP-1, were compared using

Yumiko Ohkouchi; Satoshi Tajima; Masahiro Nomura; Sadahiko Itoh



Inhibitors of lipopolysaccharide biosynthesis impair the virulence potential of Escherichia coli.  


Inhibition of 3-deoxy-manno-octulosonate cytidylytransferase (CMP-KDO transferase; EC by 8-amino-2,6-anhydro-3,8-dideoxy-D-glycero-D-talo-octonic acid (NH2dKDO) halts the growth of Gram-negative bacteria by depriving the cells of the 3-deoxy-D-manno-2-octulosonate required for the biosynthesis of the core region of the lipopolysaccharide components of the outer membrane. Low levels of this inhibitor increase the vulnerability of Escherichia coli to hydrophobic antibiotics, detergents, the complement-mediated antibacterial activity of serum, phagocytosis, and enhance the rate at which bacteria are cleared from the mouse bloodstream. PMID:1335947

Hammond, S M



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:



Reactivity of monoclonal antibody E5 with endotoxin. II. Binding to short- and long-chain smooth lipopolysaccharides.  


The murine monoclonal IgM antibody E5 has been shown to significantly reduce the mortality and morbidity of patients with Gram-negative sepsis in a multicenter randomized placebo-controlled clinical trial. The in vitro binding characteristics of monoclonal antibody (mAb) E5 were studied using highly purified smooth lipopolysaccharide (LPS) isolated from a variety of clinically relevant, wild-type Gram-negative bacteria. Using a sensitive antibody-capture assay which involves immobilized mAb E5 and a chromogenic Limulus amebocyte lysate (LAL) LPS-detection system, mAb E5 was shown to bind to all 15 smooth LPS preparations tested, including LPS isolated from Escherichia, Klebsiella, Proteus, Pseudomonas, Salmonella, Serratia and Yersinia species. When LPS was fractionated according to size by size-exclusion chromatography, mAb E5 was shown to bind to smooth LPS molecules that have long as well as short O-polysaccharide chains. These results confirm and extend those reported previously and demonstrate that the anti-lipid A mAb E5 binds specifically to a diverse spectrum of smooth LPS isolated from wild-type Gram-negative bacteria. PMID:1382882

Parent, J B; Gazzano-Santoro, H; Wood, D M; Lim, E; Pruyne, P T; Trown, P W; Conlon, P J



Associations of Escherichia coli K-12 OmpF trimers with rough and smooth lipopolysaccharides  

SciTech Connect

The associations of both rough and smooth lipopolysaccharides (LPS) with the OmpF porin of Escherichia coli K-12 were examined in galE strains deleted for ompC. Transformation with pSS37 and growth with galactose conferred the ability to assemble a Shigella dysenteriae O antigen onto the core oligosaccharide of E. coli K-12 LPS. The association of LPS with OmpF trimers was assessed by staining, autoradiography of LPS specifically labeled with (1-14C)galactose, and Western immunoblotting with a monoclonal antibody specific for OmpF trimers. These techniques revealed that the migration distances and multiple banding patterns of OmpF porin trimers in sodium dodecyl sulfate-polyacrylamide gels were dictated by the chemotype of associated LPS. Expression of smooth LPS caused almost all of the trimeric OmpF to run in gels with a slower mobility than trimers from rough strains. The LPS associated with trimers from a smooth strain differed from the bulk-phase LPS by consisting almost exclusively of molecules with O antigen.

Diedrich, D.L.; Stein, M.A.; Schnaitman, C.A. (Louisiana State Univ. Medical Center, New Orleans (USA))



A novel Escherichia coli lipid A mutant that produces an antiinflammatory lipopolysaccharide.  

PubMed Central

A unique screen was used to identify mutations in Escherichia coli lipid A biosynthesis that result in a decreased ability to stimulate E-selectin expression by human endothelial cells. A mutation was identified in the msbB gene of E. coli that resulted in lipopolysaccharide (LPS) that lacks the myristoyl fatty acid moiety of the lipid A. Unlike all previously reported lipid A mutants, the msbB mutant was not conditionally lethal for growth. Viable cells or purified LPS from an msbB mutant had a 1000-10,000-fold reduction in the ability to stimulate E-selectin production by human endothelial cells and TNF alpha production by adherent monocytes. The cloned msbB gene was able to functionally complement the msbB mutant, restoring both the LPS to its native composition and the ability of the strain to stimulate immune cells. Nonmyristoylated LPS acted as an antagonist for E-selectin expression when mixed with LPS obtained from the parental strain. These studies demonstrate a significant role for the myristate component of LPS in immune cell activation and antagonism. In addition, the msbB mutant allowed us to directly examine the crucial role that the lipid A structure plays when viable bacteria are presented to host defense cells.

Somerville, J E; Cassiano, L; Bainbridge, B; Cunningham, M D; Darveau, R P



Metabolic and Endocrine Changes in Response to Endotoxin Administration With or Without Oral Arginine Supplementation  

Microsoft Academic Search

Thisstudywasperformed toinvestigatebloodmetab- olite, tumor necrosis factor-?, and hormone responses to intravenous administration of lipopolysaccharides (2 µg of endotoxin of Escherichia coli O26:B6\\/kg body weight at times of feeding) in veal calves orally supple- mented with arginine (0.25 g\\/kg of body weight twice daily for 4 d; group GrA) compared with calves not supplementedwitharginine(groupGrC).Argininesup- plementation alone caused a significant rise of

B. R. Hüsler; J. W. Blum



Lack of defective cardiac oxidative metabolism in intact dogs subjected to a prolonged low-dose infusion of Escherichia coli endotoxin.  


The aim of the present study was to determine possible direct adverse effects of a 2-hour Escherichia coli endotoxin infusion (50 ng kg-1 min-1) on myocardial oxidative carbohydrate metabolism. The experiments were performed in intact dogs to assay glucose and lactate cardiac uptake and relate them to oxygen consumption (MVO2), CO2 production, and myocardial hemodynamics. Coronary sinus blood flow (CSBF) was measured by thermodilution, and the arteriovenous differences in glucose, lactate, pyruvate, O2, and CO2 were determined by blood samples obtained simultaneously from the carotid artery and sinus coronary. The adequacy of CSBF in meeting cardiac oxygen needs was evaluated by calculating the percentage of anaerobic metabolic rate (% AMR). During endotoxin infusion, CSBF was significantly lowered by 33% while mean aortic blood pressure was decreased by 43%. Cardiac index exhibited a minimal reduction of 14%. Mean arterial blood glucose decreased 30% and arterial lactate increased 100%. Despite the progressively developing hypoglycemia, cardiac glucose uptake increased 140%. Although MVO2 was reduced to 70% of control value, lactate uptake increased 50%. Throughout the experimental period, the % AMR remained negative. Under endotoxin infusion, up to 78% of the cardiac CO2 production was derived from carbohydrate utilization, as compared to 40% prior to endotoxin infusion. Our findings suggest the absence of any toxic action by an endotoxin-sustained infusion on cardiac oxidative metabolism. PMID:3080258

D'Orio, V; el Allaf, D; Vaira, S; Fossion, A; Juchmes, J; Marcelle, R



Pharmacokinetics of tulathromycin in healthy and neutropenic mice challenged intranasally with lipopolysaccharide from Escherichia coli.  


Tulathromycin represents the first member of a novel subclass of macrolides, known as triamilides, approved to treat bovine and swine respiratory disease. The objectives of the present study were to assess the concentration-versus-time profile of tulathromycin in the plasma and lung tissue of healthy and neutropenic mice challenged intranasally with lipopolysaccharide (LPS) from Escherichia coli O111:B4. BALB/c mice were randomly allocated into four groups of 40 mice each: groups T-28 (tulathromycin at 28 mg/kg of body weight), T-7, T7-LPS, and T7-LPS-CP (cyclophosphamide). Mice in group T-28 were treated with tulathromycin at 28 mg/kg subcutaneously (s.c.) (time 0 h). The rest of the mice were treated with tulathromycin at 7 mg/kg s.c. (time 0 h). Animals in dose groups T-7-LPS and T7-LPS-CP received a single dose of E. coli LPS intranasally at -7 h. Mice in group T7-LPS-CP were also rendered neutropenic with cyclophosphamide (150 mg/kg intraperitoneally) prior to the administration of tulathromycin. Blood and lung tissue samples were obtained from 5 mice from each dose group at each sampling time over 144 h after the administration of tulathromycin. There were not statistical differences in lung tissue concentrations among groups T-7, T-7-LPS, and T7-LPS-CP. For all dose groups, the distribution of tulathromycin in the lungs was rapid and persisted at relatively high levels during 6 days postadministration. The concentration-versus-time profile of tulathromycin in lung tissue was not influenced by the intranasal administration of E. coli LPS. The results suggest that in mice, neutrophils may not have a positive influence on tulathromycin accumulation in lung tissue when the drug is administered during either a neutrophilic or a neutropenic state. PMID:22585224

Villarino, N; Brown, S A; Martín-Jiménez, T



Role of lipopolysaccharide in the receptor function for bacteriophage TuIb in Escherichia coli.  

PubMed Central

Bacteriophage TuIb required lipopolysaccharide in addition to the OmpC trimer as a receptor component. Both the fatty acid and polysaccharide regions of lipopolysaccharide were shown to participate in the receptor function. The roles of lipopolysaccharide and outer membrane proteins in the receptor function for T-even type bacteriophages are discussed. Images

Yu, F; Yamada, H; Mizushima, S



Regulation by a novel protein of the bimodal distribution of lipopolysaccharide in the outer membrane of Escherichia coli.  

PubMed Central

We report on the cloning and characterization of the rfb gene cluster of the O75 lipopolysaccharide from a urinary tract isolate of Escherichia coli. Deletion cloning defined the minimum region of DNA that expressed the O75 antigen in E. coli host strains to be on a 12.4-kb insert. However, the E. coli strain expressing this region did not produce a polymerized O chain as detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining. A slightly larger DNA clone of 13.4 kb produced a polymerized O chain in E. coli S phi 874 but was found to be abnormal in its distribution over the surface membrane. Normal wild-type E. coli, as with Salmonella spp., has a bimodal distribution of the lipopolysaccharide on the surface which is seen as an abundance of long and short O chains attached to the lipid A-core structure. We found in a region adjacent to the cloned rfb region, and on the opposite side from where the putative polymerase (rfc) is encoded, a novel protein of 35.5 kDa expressed from a 1.75-kb DNA fragment. This protein was shown to complement in trans the E. coli strains carrying plasmids that expressed abnormal, unregulated lipopolysaccharides. The expression of these complemented strains was bimodal in distribution. Mutation of the gene encoding this protein destroyed its ability to regulate O-chain distribution. We propose to call this regulator gene rol, for regulator of O length. Images

Batchelor, R A; Haraguchi, G E; Hull, R A; Hull, S I



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

Microsoft Academic Search

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.

Alice F Viana; Izaque S Maciel; Fabiana N Dornelles; Claudia P Figueiredo; Jarbas M Siqueira; Maria M Campos; Joăo B Calixto



Interaction of antimicrobial peptide s-thanatin with lipopolysaccharide in vitro and in an experimental mouse model of septic shock caused by a multidrug-resistant clinical isolate of Escherichia coli.  


s-thanatin, an analogue of thanatin, was synthesised by substituting the fifteenth amino acid threonine with serine and showed broad antimicrobial activity against Gram-negative and Gram-positive bacteria. To evaluate its antimicrobial activity against a multidrug-resistant (MDR) clinical isolate as well as its anti-endotoxin activity, its lipopolysaccharide (LPS)-binding and -neutralising activity in vitro and its therapeutic efficacy in an experimental model of septic shock caused by a MDR clinical isolate of Escherichia coli were studied. The ability of s-thanatin to bind or neutralise LPS from E. coli O111:B4 was determined using a quantitative assay kit. Male ICR mice were given an intraperitoneal (i.p.) administration of 2x10(10) colony-forming units of E. coli E79466. Following bacterial challenge, all animals were randomised to receive i.p. administration of saline, 40mg/kg ceftazidime (CAZ), or 40mg/kg CAZ+s-thanatin (10, 20 or 40mg/kg). The results showed that s-thanatin not only completely bound to the LPS (median effective concentration of 17.5microg/mL) but also improved the survival and reduced the number of inoculated bacteria in a mouse model of septic shock. s-thanatin may be an attractive candidate to develop as an anti-MDR bacterial agent. PMID:20045294

Wu, Guoqiu; Fan, Xiaobo; Li, Linxian; Wang, Hailiang; Ding, Jiaxuan; Hongbin, Wu; Zhao, Rui; Gou, Lixia; Shen, Zilong; Xi, Tao




PubMed Central

The greater susceptibility to the lethal effects of bacterial endotoxin (heat-killed Salmonella typhimurium or Escherichia coli lipopolysaccharide, in mice infected with an attenuated strain of Mycobacterium tuberculosis (BCG) was confirmed. It reached a maximum at 2 weeks postinfection and gradually diminished for an additional 6 weeks. At the time of maximum susceptibility several metabolic and physiological differences became apparent. BCG-infected mice die sooner (4 to 12 hours) and without the diarrhea, conjunctivitis, and general symptomatology associated with endotoxin deaths of normal animals. Reticuloendothelial blockade results in only a small change in reactivity to endotoxin, in contrast to normal mice. Subcutaneous injection of 2 units of ACTH is followed by no significant increase in urinary nitrogen excretion while in control animals it more than doubles. Plasma clearance of intravenously administered inulin is approximately normal in BCG-infected mice 17 hours after an LD50 dose of endotoxin but control mice similarly treated show renal impairment. In line with this result is the absence of elevated carcass non-protein nitrogen (NPN) following endotoxin poisoning or at the moment of death from endotoxemia in the hyperreactive animals in contrast to the two- to threefold increase in carcass NPN in normal mice under similar conditions. Body carbohydrate is at a minimum and becomes depleted to a level approximating that found at death more rapidly in BCG-infected mice given endotoxin than in controls. There is also a lower ratio of carbohydrate anabolized to protein catabolized following cortisone administration to BCG-infected mice than in control mice. This is found in adrenalectomized mice and in stressed animals and is reported elsewhere. Some of the differences just described can be attributed to a refractory adrenal cortex. There is less depletion of adrenal cholesterol in vivo and lower corticoid synthesis in vitro than in normal mice yet this is not fundamentally responsible for the greater susceptibility of BCG-infected animals to endotoxin since adrenalectomized mice, which are even more susceptible, are metabolically and physiologically more comparable to normal mice than to BCG-infected mice. One can conclude, therefore, that the hyperreactivity of BCG-infected mice is more than an intensification of the normal response to endotoxin.

Berry, L. Joe; Smythe, Dorothy S.; Kolbye, Susannah McC.



Apoptosis of tiger shrimp (Penaeus monodon) haemocytes induced by Escherichia coli lipopolysaccharide.  


This study was aimed at investigating the toxicity mechanism of lipopolysaccharide (LPS) on Penaeus monodon haemocytes at a cellular level. Reactive oxygen species (ROS) production, nitric oxide (NO) production, non-specific esterase activity, cytoplasmic free-Ca(2+) (CF-Ca(2+)) concentration, DNA damaged cell ratio and apoptotic cell ratio of in vitro LPS-treated haemocytes were measured by flow cytometry. Two concentrations of Escherichia coli LPS (5 and 10 ?g mL(-1)) were used. Results showed that ROS production, NO production and CF-Ca(2+) concentration were significantly induced in the LPS-treated haemocytes. Ratio of DNA damaged cell and apoptotic cell increased caused by LPS, while esterase activity increased at the initial 60 min and dropped later. The initial increase in esterase activity suggested that LPS activated the release of esterase, and the later decrease might result from apoptosis. These results indicated that LPS would induce oxidative stress on shrimp haemocytes, and cause Ca(2+) release, DNA damage and subsequently cell apoptosis. This process of ROS/RNS-induced Ca(2+)-mediated apoptosis might be one of the toxicity mechanisms of LPS on shrimp haemocytes. PMID:23073356

Xian, Jian-An; Miao, Yu-Tao; Li, Bin; Guo, Hui; Wang, An-Li



Absence of complement fixing antibodies against lipopolysaccharides from Escherichia coli in a subgroup of patients with Crohn's disease.  

PubMed Central

Complement fixing antibodies against different Escherichia coli lipopolysaccharides were determined in patients with Crohn's disease and in healthy individuals and compared with antitetanus toxoid antibodies. All healthy individuals had antilipopolysaccharide antibodies, 10 of 27 patients with Crohn's disease had no antibodies and six had rapidly changing antibody titres. These abnormalities were found in patients with disease in the colon, with arthropathy and fistula. Antilipid A was found at lower titres in Crohn's disease. Neither antitetanus toxoid antibodies, nor immunoglobulin concentrations were different in patients with or without antilipopolysaccharide antibodies. There was no evidence for circulating immune complexes in patients lacking antilipopolysaccharide antibodies. Certain subgroups of patients with Crohn's disease have altered antibody levels to typical enteral antigens which most likely can be explained by local antibody binding to lipopolysaccharides at inflammatory sites, or by changes in immunoregulation in this disease.

Zeitz, M; Hope, U; Wust, B; Galanos, C; Moller, B; Lawley, T J; Riecken, E O



Endotoxin in germfree, gnotobiotic, or conventional-flora Sprague-Dawley rats.  


The Limulus assay for bacterial endotoxin was performed on serum and (or) plasma from animals monoassociated with Clostridium species, Staphylococcus aureus, Escherichia coli, Proteus mirabilis, Enterobacter agglomerans, Bacteroides fragilis, Klebsiella pneumoniae, or Candida albicans. Plasma from animals monoassociated with the gram-negative bacteria or C. albicans consistently showed a positive Limulus test while conventional-flora controls, germfree rats, and gnotobiotic animals monoassociated with gram-positive bacteria or E. agglomerans were negative. Germfree and conventional rats were injected (intraperitoneal (i.p.)) with Salmonella typhosa lipopolysaccharide (LPS). Although no endotoxin was detectable in either group prior to the injection, by 1 h post injection endotoxin was in the plasma of all groups. The germfree rats appeared to clear the LPS quicker than their conventional-flora counterparts. Generally, LPS-injected rats (conventional and germfree) showed clumping and decreased number of platelets, a decrease in their lymphocyte counts, and increased polymorphonuclear leukocyte (PMN) counts. PMID:371771

McLeod, J C; Balish, E



Early effects of Escherichia coli endotoxin infusion on vasopressin-stimulated breakdown and metabolism of inositol lipids in rat hepatocytes  

SciTech Connect

The turnover of vasopressin-stimulated 32P-phosphoinositides and 32P-phosphatidic acid and accumulation of (2-3H)-inositol phosphates were examined in hepatocytes from rats infused i.v. with saline and E. coli endotoxin for 3 hrs. Within 60s of VP stimulation the decrease in phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate labeling as well as the increased uptake of 32P into phosphatidic acid were similar in both groups. However, at a later time (300s) the 32P-phosphatidylinositol turnover was greatly decreased concomitantly with a higher labeling of phosphatidic acid. The accumulation of (2-3H)-inositol phosphates in ET-cells was significantly decreased both at 30s and 600s after VP addition. The distribution of (2-3H)-inositol labeling accumulated in the different inositol phosphate fractions over the first 30s of VP stimulation showed a tendency to lower accumulation of inositol trisphosphate, and a significantly lower accumulation of inositol bisphosphate simultaneously with a higher labeling of the inositol tetrakisphosphate fraction. These observations reflect an early effect of ET-infusion on VP-stimulated inositol lipid turnover and on the subsequent metabolism of the released inositol phosphates.

Rodriguez de Turco, E.B.; Spitzer, J.A.



Molecular Dynamics and NMR Spectroscopy Studies of E. coli Lipopolysaccharide Structure and Dynamics.  


Lipopolysaccharide (LPS), a component of Gram-negative bacterial outer membranes, comprises three regions: lipid A, core oligosaccharide, and O-antigen polysaccharide. Using the CHARMM36 lipid and carbohydrate force fields, we have constructed a model of an Escherichia coli R1 (core) O6 (antigen) LPS molecule. Several all-atom bilayers are built and simulated with lipid A only (LIPA) and varying lengths of 0 (LPS0), 5 (LPS5), and 10 (LPS10) O6 antigen repeating units; a single unit of O6 antigen contains five sugar residues. From (1)H,(1)H-NOESY experiments, cross-relaxation rates are obtained from an O-antigen polysaccharide sample. Although some experimental deviations are due to spin-diffusion, the remaining effective proton-proton distances show generally very good agreement between NMR experiments and molecular dynamics simulations. The simulation results show that increasing the LPS molecular length has an impact on LPS structure and dynamics and also on LPS bilayer properties. Terminal residues in a LPS bilayer are more flexible and extended along the membrane normal. As the core and O-antigen are added, per-lipid area increases and lipid bilayer order decreases. In addition, results from mixed LPS0/5 and LPS0/10 bilayer simulations show that the LPS O-antigen conformations at a higher concentration of LPS5 and LPS10 are more orthogonal to the membrane and less flexible. The O-antigen concentration of mixed LPS bilayers does not have a significant effect on per-lipid area and hydrophobic thickness. Analysis of ion and water penetration shows that water molecules can penetrate inside the inner core region, and hydration is critical to maintain the integrity of the bilayer structure. PMID:24047996

Wu, Emilia L; Engström, Olof; Jo, Sunhwan; Stuhlsatz, Danielle; Yeom, Min Sun; Klauda, Jeffery B; Widmalm, Göran; Im, Wonpil



Replacement of Lipopolysaccharide with Free Lipid A Molecules in Escherichia coli Mutants Lacking All Core Sugars  

PubMed Central

Escherichia coli mutants deficient in 2-keto-3-deoxy-d-manno-octulosonic acid (Kdo) biosynthesis are conditionally lethal, but their phenotypes are bypassed by certain suppressor mutations or by over-expression of MsbA, the inner membrane flippase for core-lipid A. These strains grow on broth with the tetra-acylated precursor lipid IVA replacing lipopolysaccharide (Meredith, T. C. et al. ACS Chem. Biol. 1, 33–42, 2006). Deletion of kdtA, which encodes the Kdo transferase, is possible under these conditions. We now show that lipid IVA reaches the outer surface of the outer membrane in these strains, as judged by its accessibility to the lipase PagL. On the assumption that MsbA is optimized to transport penta- or hexa-acylated lipid A, we over-expressed the lauroyl or the myristoyl transferase of lipid A biosynthesis, encoded by lpxL and lpxM respectively, and demonstrated that kdtA deletion mutants were also viable in this setting. Although E. coli LpxL is stimulated by the presence of the Kdo-disaccharide in its acceptor substrate, LpxL does slowly acylate lipid IVA. Over-expression of LpxL from a plasmid suppressed the lethality of kdtA deletions on nutrient broth at 30 or 37 °C without the need for MsbA over-production. These strains accumulated penta- and hexa-acylated free lipid A containing a secondary laurate chain, or a laurate and a myristate chain, respectively. Deletion of kdtA in strains over-expressing LpxM accumulated penta-acylated lipid A with a secondary myristate moiety. None of the strains lacking kdtA grew in the presence of bile salts at any temperature or on nutrient broth at 42 °C. Our findings show that the main function of Kdo is to provide the right substrates for the acyltransferases LpxL and LpxM, resulting in the synthesis of penta- and hexa-acylated lipid A, which is optimal for the MsbA flippase.

Reynolds, C. Michael; Raetz, Christian R. H.



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.

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



Structural characterization of the antigenic O-chain of the lipopolysaccharide of Escherichia coli serotype O65  

Microsoft Academic Search

The antigenic O-polysaccharide moiety of the lipopolysaccharide produced by Escherichia coli serotype O65 was investigated by composition, methylation, base hydrolysis, periodate oxidation, mass spectrometric methods, and by 1D and 2D NMR spectroscopy. The O-polysaccharide had [?]D+108° (water) and is a high-molecular-weight unbranched linear polymer of repeating pentasaccharide units composed of 1:1:1:1:1 d-galacturonic acid (d-GalA), d-galacturonamide (d-GalANH2), 2-acetamido-2-deoxy-d-glucose (d-GlcNAc), 2-acetamido-2-deoxy-d-galactose (d-GalNAc),

Malcolm B. Perry; Leann L. MacLean



Colicin A receptor: role of two Escherichia coli outer membrane proteins (OmpF protein and btuB gene product) and lipopolysaccharide.  

PubMed Central

ompF cells were completely resistant to colicin A, whereas btuB cells were partially resistant. The OmpF protein, in the presence of added lipopolysaccharide, inactivated colicin A. This inactivation was enhanced by added btuB gene product, btuB gene product with lipopolysaccharide did not inactivate colicin A. These data, together with the observation that vitamin B12 protected btuB+ cells from the killing effect of colicin A, suggest that the colicin A receptor in Escherichia coli K-12 is composed of the OmpF protein, the btuB gene product, and lipopolysaccharide.

Chai, T; Wu, V; Foulds, J



Specific incorporation of glycine into bacterial lipopolysaccharide. Novel function of specific transfer ribonucleic acids.  

PubMed Central

It has been found that the bacterial endotoxins (lipopolysaccharides, LPSs) contain some amino acids and glycine is the most abundant amino acid in the polysaccharide core preparations of LPSs of gram-negative bacteria. Until now nothing was known about the mechanism of amino acid incorporation into the lipopolysaccharide core. We found that one out of three glycyl-tRNAs(Gly) from Escherichia coli is the donor of amino acid and is the substrate for a putative aminoacyl-tRNA:LPS transferase. We have isolated, purified this tRNA and determined its nucleotide sequence to be major E.coli tRNA(3Gly). This tRNA(Gly) (anticodon GCC) conserved the tRNA structural features. The assay for determination of the specific incorporation of glycine into the lipopolysaccharide was also invented and described. Images

Gamian, A; Krzyzaniak, A; Barciszewska, M Z; Gawronska, I; Barciszewski, J



Intratracheal Recombinant Surfactant Protein D Prevents Endotoxin Shock in the Newborn Preterm Lamb  

PubMed Central

Rationale: The susceptibility of neonates to pulmonary and systemic infection has been associated with the immaturity of both lung structure and the immune system. Surfactant protein (SP) D is a member of the collectin family of innate immune molecules that plays an important role in innate host defense of the lung. Objectives: We tested whether treatment with recombinant human SP-D influenced the response of the lung and systemic circulation to intratracheally administered Escherichia coli lipopolysaccharides. Methods: After intratracheal lipopolysaccharide instillation, preterm newborn lambs were treated with surfactant and ventilated for 5 h. Measurement: Survival rate, physiologic lung function, lung and systemic inflammation, and endotoxin level in plasma were evaluated. Main Results: In control lambs, intratracheal lipopolysaccharides caused septic shock and death associated with increased endotoxin in plasma. In contrast, all lambs treated with recombinant human SP-D were physiologically stable and survived. Leakage of lipopolysaccharides from the lungs to the systemic circulation was prevented by intratracheal recombinant human SP-D. Recombinant human SP-D prevented systemic inflammation and decreased the expression of IL-1?, IL-8, and IL-6 in the spleen and liver. Likewise, recombinant human SP-D decreased IL-1? and IL-6 in the lung and IL-8 in the plasma. Recombinant human SP-D did not alter pulmonary mechanics following endotoxin exposure. Recombinant human SP-D was readily detected in the lung 5 h after intratracheal instillation. Conclusions: Intratracheal recombinant human SP-D prevented shock caused by endotoxin released from the lung during ventilation in the premature newborn.

Ikegami, Machiko; Carter, Karen; Bishop, Kimberly; Yadav, Annuradha; Masterjohn, Elizabeth; Brondyk, William; Scheule, Ronald K.; Whitsett, Jeffrey A.



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

Microsoft Academic Search

Endotoxin tolerance is defined as a reduced responsiveness to a lipopolysaccharide (LPS) challenge following a first encounter\\u000a with endotoxin. Endotoxin tolerance protects against a lethal challenge of LPS and prevents infection and ischemia-reperfusion\\u000a damage. Endotoxin tolerance is paralleled by a dramatic reduction of tumor necrosis factor (TNF) production and some other\\u000a cytokines in response to LPS. Endotoxin tolerance involves the

Jean-Marc Cavaillon; Minou Adib-Conquy




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...


Effects of endotoxin tolerance on Propionibacterium acnes-primed lipopolysaccharide hepatic injury 1,2 1 Presented at the annual meeting of the Association of Academic Surgery, Boston, MA, November 7–8, 2002. 2 Supported by NIH AI4296701 (to M.W.F.); Society of University Surgeons\\/Ethicon, American Liver Foundation, and NRSA AI1060902 (to J.A.M.)  

Microsoft Academic Search

Background. Prior administration of the Gram-positive bacteria Propionibacterium acnes (PA) results in hypersensitivity and hepatocyte necrosis to a subsequent low dose of lipopolysaccharide (LPS). Endotoxin tolerance has been shown to prevent lethality after ischemia\\/reperfusion injuries, sepsis, and endotoxic shock. We investigated whether prior induction of LPS tolerance could prevent subsequent PA-priming and LPS-induced death. The levels of known effector cytokines

Julie A Margenthaler; Keith Landeros; Masaaki Kataoka; Mark Eilers; Grace Ku; M. Wayne Flye



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.

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



Recent advances in biosensor based endotoxin detection.  


Endotoxins also referred to as pyrogens are chemically lipopolysaccharides habitually found in food, environment and clinical products of bacterial origin and are unavoidable ubiquitous microbiological contaminants. Pernicious issues of its contamination result in high mortality and severe morbidities. Standard traditional techniques are slow and cumbersome, highlighting the pressing need for evoking agile endotoxin detection system. The early and prompt detection of endotoxin assumes prime importance in health care, pharmacological and biomedical sectors. The unparalleled recognition abilities of LAL biosensors perched with remarkable sensitivity, high stability and reproducibility have bestowed it with persistent reliability and their possible fabrication for commercial applicability. This review paper entails an overview of various trends in current techniques available and other possible alternatives in biosensor based endotoxin detection together with its classification, epidemiological aspects, thrust areas demanding endotoxin control, commercially available detection sensors and a revolutionary unprecedented approach narrating the influence of omics for endotoxin detection. PMID:23934306

Das, A P; Kumar, P S; Swain, S



The efficient removal of endotoxins from insulin using quaternized polyethyleneimine-coated porous zirconia.  


The synthesis and use of a zirconia-based, alkali-stable strong anion-exchange stationary phase are described for the removal of pyrogenic lipopolysaccharides (LPS) from insulin. The strong anion-exchange material is produced by deposition of polyethyleneimine (PEI) onto porous zirconia particles, followed by cross-linking with a novel reagent, 1,2-bis-(2-iodoethoxy) ethane, and quaternization with iodomethane. Physical characterization of the chromatographic support shows that it has an ion-exchange capacity of 0.6 mmol/g, and 82% of the amine sites on the surface are in quaternized form. Isocratic elution of small benzoic acid derivatives shows good column efficiency. The two primary virtues of this material are its chemical stability under alkali conditions (up to pH 13) and its lower hydrophobicity compared to previously described alkali-stable PEI-coated zirconia supports cross-linked with 1,10-diiododecane. Using this new zirconia-based phase, a purification protocol is developed for the efficient removal of Escherichia coli 0111:B4 LPS from bovine insulin samples. An endotoxin clearance rate of up to 1.3 x 10(8) was attained. Endotoxin levels were reduced to less than 5 endotoxin units/ml even at initial contamination levels as high as 5.0 x 10(6) endotoxin units/ml. Furthermore, endotoxin adsorbed to the porous zirconia column may be easily removed (depyrogenated) using alkali for repeated purification cycles. PMID:10527514

McNeff, C; Zhao, Q; Almlöf, E; Flickinger, M; Carr, P W



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.

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



Structural characterization of the antigenic O-chain of the lipopolysaccharide of Escherichia coli serotype O65.  


The antigenic O-polysaccharide moiety of the lipopolysaccharide produced by Escherichia coli serotype O65 was investigated by composition, methylation, base hydrolysis, periodate oxidation, mass spectrometric methods, and by 1D and 2D NMR spectroscopy. The O-polysaccharide had [alpha]D + 108 degrees (water) and is a high-molecular-weight unbranched linear polymer of repeating pentasaccharide units composed of 1:1:1:1:1 D-galacturonic acid (D-GalA), D-galacturonamide (D-GalANH2), 2-acetamido-2-deoxy-D-glucose (D-GlcNAc), 2-acetamido-2-deoxy-D-galactose (D-GalNAc), and 3-acetamido-3,6-dideoxy-D-glucose (D-Qui3NAc), and has the following structure: [formula: see text] PMID:10629949

Perry, M B; MacLean, L L



The effect of doxazosin, urapidil and indoramin pretreatment on fever produced by E. coli lipopolysaccharide in rabbits.  


1. Thermal responses to i.v. administration of doxazosin (0.75 or 1.50 mg/kg), urapidil (5.0 or 10.0 mg/kg), or indoramin (0.75 or 1.50 mg/kg) were investigated in febrile rabbits (treated with Escherichia coli lipopolysaccharide) at an ambient temperature of 19 +/- 1 degree C. 2. All these alpha 1-adrenoceptor blockers produced statistically significant antipyresis which developed as a result of inhibition of metabolic heat production and/or stimulation of heat elimination from the ear skin area or respiratory tract. 3. It appears that the antipyretic effect is a general feature of alpha 1-adrenergic receptor blockers. The possible mechanisms by which antipyresis is produced are being considered. PMID:1684772

Gaga?o, I; Szreder, Z



Glycosyltransferases involved in biosynthesis of the outer core region of Escherichia coli lipopolysaccharides exhibit broader substrate specificities than is predicted from lipopolysaccharide structures.  


The waaJ, waaT, and waaR genes encode alpha-1,2-glycosyltransferases involved in synthesis of the outer core region of the lipopolysaccharide of Escherichia coli. They belong to the glycosyltransferase CAZy family 8, characterized by the GT-A fold, DXD motifs, and by retention of configuration at the anomeric carbon of the donor sugar. Each enzyme adds a hexose residue at the same stage of core oligosaccharide backbone extension. However, they differ in the epimers for their donor nucleotide sugars, and in their acceptor residues. WaaJ is a UDP-glucose: (galactosyl) LPS alpha-1,2-glucosyltransferase, whereas WaaR and WaaT have UDP-glucose:(glucosyl) LPS alpha-1,2-glucosyltransferase and UDP-galactose:(glucosyl) LPS alpha-1,2-galactosyltransferase activities, respectively. The objective of this work was to examine their ability to utilize alternate donors and acceptors. When expressed in the heterologous host, each enzyme was able to extend the alternate LPS acceptor in vivo but they retained their natural donor specificity. In vitro assays were then performed to test the effect of substituting the epimeric donor sugar on incorporation efficiency with the natural LPS acceptor of the enzyme. Although each enzyme could utilize the alternate donor epimer, activity was compromised because of significant decreases in k(cat) and corresponding increases in K(m)(donor). Finally, in vitro assays were performed to probe acceptor preference in the absence of the cellular machinery. The results were enzyme-dependent: while an alternate acceptor had no significant effect on the kinetic behavior of His(6)-WaaT, His(6)-WaaJ showed a significantly decreased k(cat) and increased K(m)(acceptor). These results illustrate the differences in behavior between closely related glycosyltransferase enzymes involved in the synthesis of similar glycoconjugates and have implications for glycoengineering applications. PMID:17631498

Leipold, Michael D; Vinogradov, Evgeny; Whitfield, Chris



Antigenic relationships of the lipopolysaccharides of Escherichia hermannii strains with those of Escherichia coli O157:H7, Brucella melitensis, and Brucella abortus.  

PubMed Central

Clinical isolates of Escherichia hermannii which showed serological cross-reaction with polyclonal antisera to the O-polysaccharide portion of the lipopolysaccharide of E. coli O157 strains and with antisera to the O antigens of Brucella abortus and B. melitensis were found by chemical and nuclear magnetic resonance analyses to have lipopolysaccharide O chains composed of linear polymers containing 1,2- and 1,3-linked 4-acetamido-4,6-dideoxy-alpha-D-mannopyranosyl (alpha-D-Rhap4NAc) residues. Two O-antigen structures were identified; each had an unbranched pentasaccharide repeating unit, and one was composed of three 1,2- and two 1,3-linked alpha-D-Rhap4NAc residues and the other had two 1,2- and three 1,3-linked alpha-D-Rhap4NAc residues. The above-described cross-serological reactivities, which have led to false-positive identifications, are related to the common occurrence of epitopes involving the presence of N-acyl derivatives of 4-amino-4,6-dideoxy-D-mannopyranosyl residues in the O-polysaccharide portions of the respective lipopolysaccharides of the organisms. Strains of E. hermannii which did not show serological cross-reactions with E. coli O157 and Brucella antisera were found to have unique lipopolysaccharide O chains devoid of D-Rhap4NAc residues, demonstrating the existence of serotypes of E. hermannii that are distinct on the basis of their lipopolysaccharide components. Images

Perry, M B; Bundle, D R



Antigenic relationships of the lipopolysaccharides of Escherichia hermannii strains with those of Escherichia coli O157:H7, Brucella melitensis, and Brucella abortus.  


Clinical isolates of Escherichia hermannii which showed serological cross-reaction with polyclonal antisera to the O-polysaccharide portion of the lipopolysaccharide of E. coli O157 strains and with antisera to the O antigens of Brucella abortus and B. melitensis were found by chemical and nuclear magnetic resonance analyses to have lipopolysaccharide O chains composed of linear polymers containing 1,2- and 1,3-linked 4-acetamido-4,6-dideoxy-alpha-D-mannopyranosyl (alpha-D-Rhap4NAc) residues. Two O-antigen structures were identified; each had an unbranched pentasaccharide repeating unit, and one was composed of three 1,2- and two 1,3-linked alpha-D-Rhap4NAc residues and the other had two 1,2- and three 1,3-linked alpha-D-Rhap4NAc residues. The above-described cross-serological reactivities, which have led to false-positive identifications, are related to the common occurrence of epitopes involving the presence of N-acyl derivatives of 4-amino-4,6-dideoxy-D-mannopyranosyl residues in the O-polysaccharide portions of the respective lipopolysaccharides of the organisms. Strains of E. hermannii which did not show serological cross-reactions with E. coli O157 and Brucella antisera were found to have unique lipopolysaccharide O chains devoid of D-Rhap4NAc residues, demonstrating the existence of serotypes of E. hermannii that are distinct on the basis of their lipopolysaccharide components. PMID:1691146

Perry, M B; Bundle, D R



Endotoxin emissions from commercial composting activities  

PubMed Central

This paper describes an exploratory study of endotoxin emissions and dispersal from a commercial composting facility. Replicated samples of air were taken by filtration at different locations around the facility on 10 occasions. Measurements were made of endotoxin and associated culturable microorganisms. The inflammatory response of cell cultures exposed to extracts from the filters was measured. Endotoxin was detected in elevated concentrations close to composting activities. A secondary peak, of lesser magnitude than the peak at source was detected at 100-150 m downwind of the site boundary. Unexpectedly high concentrations of endotoxin were measured at the most distant downwind sampling point. Extracted endotoxin was found to stimulate human monocytes and a human lung epithelial cell line to produce significant amounts of pro-inflammatory cytokines. On a weight basis, endotoxin extracted from the composting source has a greater inflammatory cytokine inducing effect than commercial E. coli endotoxin.



Escherichia coli and its lipopolysaccharide modulate in vitro Candida biofilm formation.  


Demystification of microbial behaviour in mixed biofilms could have a major impact on our understanding of infectious diseases. The objectives of this study were to evaluate in vitro the interactions of six different Candida species and a Gram-negative coliform, Escherichia coli, in dual-species biofilms, and to assess the effect of E. coli LPS on Candida biofilm formation. A single isolate of E. coli ATCC 25922 and six different species of Candida, Candida albicans ATCC 90028, Candida glabrata ATCC 90030, Candida krusei ATCC 6258, Candida tropicalis ATCC 13803, Candida parapsilosis ATCC 22019 and Candida dubliniensis MYA-646, were studied using a standard biofilm assay. Each Candida species was co-cultured with E. coli on a polystyrene surface and biofilm formation was quantified by a c.f.u. assay. The biofilm was then analysed by Live/Dead staining and fluorescence microscopy (confocal laser-scanning microscopy, CLSM), whilst scanning electron microscopy (SEM) was employed to visualize the biofilm architecture. The effect of E. coli LPS on Candida biofilm cell activity at defined time intervals was assessed with an XTT reduction assay. A significant quantitative reduction in c.f.u. counts of C. tropicalis (after 90 min), C. parapsilosis (after 90 min and 24 h), C. krusei (after 24 h) and C. dubliniensis (after 24 and 48 h) was noted on incubation with E. coli in comparison with their monospecies biofilm counterparts (P <0.05). On the other hand, a simultaneous and significant reduction in E. coli cell numbers occurred on co-culture with C. albicans (after 90 min), and an elevation of E. coli cell numbers followed co-culture with C. tropicalis (after 24 h) and C. dubliniensis (after 24 h and 48 h) (P <0.05). All quantitative findings were confirmed by SEM and CLSM analyses. By SEM observation, dual-species biofilms demonstrated scanty architecture with reduced visible cell counts at all stages of biofilm development, despite profuse growth and dense colonization in their single-species counterparts. Significantly elevated metabolic activity, as assessed by XTT readings, was observed in E. coli LPS-treated C. tropicalis and C. parapsilosis biofilms (after 48 h), whilst this had the opposite effect for C. dubliniensis (after 24 h) (P <0.05). These data indicate that E. coli and Candida species in a mixed-species environment mutually modulate biofilm development, both quantitatively and qualitatively, and that E. coli LPS appears to be a key component in mediating these outcomes. PMID:19661208

Bandara, H M H N; Yau, J Y Y; Watt, R M; Jin, L J; Samaranayake, L P



Structural similarities among malaria toxins insulin second messengers, and bacterial endotoxin.  

PubMed Central

Malaria toxin causes hypoglycemia and induction of tumor necrosis factor. Extracts of parasitized erythrocytes which were coeluted and copurified with one of the two subtypes of mammalian insulin-mimetic inositolphosphoglycans similarly induced fibroblast proliferation in the absence of serum. In addition, induction of tumor necrosis factor in macrophages by malaria toxin and by lipopolysaccharide from Escherichia coli was enhanced by pretreatment of these toxins with alpha-galactosidase. Thus, parasitized erythrocytes contain both soluble inositolphosphoglycan-like insulin second messengers and endotoxin-like lipidic molecules.

Caro, H N; Sheikh, N A; Taverne, J; Playfair, J H; Rademacher, T W



Recombinant immunotoxins with low endotoxins for clinical and animal studies.  


Recombinant immunotoxin (RIT) contains the Fv portion of the antibody fused to the truncated form of toxin and are ongoing in clinical trials for cancer therapy. To obtain high yields of products, RITs are produced in Escherichia coli (E. coli). As the endotoxin came from E. coli cells and is harmful to animals, it is important to produce the RITs with low endotoxin. This section describes the protocols to produce RITs containing low level of endotoxins. PMID:22907377

Onda, Masanori




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 ...


Unique genome-wide transcriptome profiles of chicken macrophages exposed to Salmonella-derived endotoxin  

Microsoft Academic Search

BACKGROUND: Macrophages play essential roles in both innate and adaptive immune responses. Bacteria require endotoxin, a complex lipopolysaccharide, for outer membrane permeability and the host interprets endotoxin as a signal to initiate an innate immune response. The focus of this study is kinetic and global transcriptional analysis of the chicken macrophage response to in vitro stimulation with endotoxin from Salmonella

Ceren Ciraci; Christopher K Tuggle; Michael J Wannemuehler; Dan Nettleton; Susan J Lamont



[A Case of Septic Shock Caused by Extended Spectrum ?-Lactamase Producing Escherichia Coli after Transrectal Prostate Biopsy, Successfully Treated by Endotoxin Adsorption Therapy].  


A 62-year-old man, with a family history of prostate cancer, referred to our hospital because of elevated prostate-specific antigen (PSA) (6.02 ng/ml). After prophylactic administration of antibiotics (cefotiam), transrectal needle biopsy of the prostate was performed. He was admitted to the hospital due to high fever the next evening. His blood pressure was below the shock level, and his renal function deteriorated progressively. Suspecting septic shock, the patient was treated with Meropenem, ?-globulin, and dopamine, which were not effective. Then, endotoxin adsorption therapy was employed and the condition of the patient recovered soon after the initiation of the therapy. Extended spectrum ? -lactamase-producing Escherichia coli was found in his urine. Pathological diagnosis of the biopsy specimen was atypical glands. PMID:24113759

Kohno, Yusuke; Fukui, Naotaka; Kageyama, Yukio; Higashi, Yotsuo



Isolation and Purification of Endotoxin by Hydrolytic Enzymes  

PubMed Central

Various commercial hydrolases were used in an attempt to degrade the endotoxic lipopolysaccharide macromolecule. Some inert components, such as peptides and nucleic acids, could be removed from endotoxin preparations. As a result, endotoxic activity, measured by pyrogenicity, Shwartzman reaction, and mouse lethality, was increased. The remarkable resistance of endotoxin to hydrolases led to the use of such enzymes for the liberation and purification of endotoxin from whole bacterial cells.

Lehrer, Samuel; Nowotny, Alois



Serological characterisation of anti-endotoxin sera directed against the conjugates of oligosaccharide core of Escherichia coli type R1, R2, R3, J5 and Salmonella Ra with tetanus toxoid.  


The covalent conjugates of oligosaccharide core: Escherichia coli type R1, R2, R3, J5 and Salmonella Ra with tetanus toxoid have been prepared using reaction of reductive amination. The neoglycoconjugates were good immunogens in rabbits yielding a high level of anti-lipopolysaccharide antibodies of IgG class. The antibodies were used to examine the possibility of their reactions with smooth lipopolysaccharides. We have found that all antisera were able to react with the lipopolysaccharide molecules of identical or related core type, possessing core oligosaccharides substituted with O-specific chains. These reactions were shown in both the ELISA assay and the immunoblotting test. PMID:8954349

Lugowski, C; Jachymek, W; Niedziela, T; Rowinski, S



Effect of ?-aminolevulinic acid on growth performance, nutrient digestibility, blood parameters and the immune response of weanling pigs challenged with Escherichia coli lipopolysaccharide  

Microsoft Academic Search

This study investigated the effects of dietary ?-aminolevulinic acid (ALA) on growth performance, nutrient digestibility, blood parameters and whether ALA improved the immune response of weanling pigs challenged with Escherichia coli lipopolysaccharide (LPS). Eighty pigs (body weight=7.21±0.51 kg) were allotted to four dietary treatments, with four pens per treatment and five pigs per pen. Basal diets were supplemented with 0, 5,

Y. J. Chen; I. H. Kim; J. H. Cho; B. J. Min; J. S. Yoo; Q. Wang



Helical Disposition of Proteins and Lipopolysaccharide in the Outer Membrane of Escherichia coli  

Microsoft Academic Search

In bacteria, several physiological processes once thought to be the products of uniformly dispersed reactions are now known to be highly asymmetric, with some exhibiting interesting geometric localizations. In particular, the cell envelope of Escherichia coli displays a form of subcellular differentiation in which peptidoglycan and outer membrane proteins at the cell poles remain stable for generations while material in

Anindya S. Ghosh; Kevin D. Young



Effect of enterotoxigenic Escherichia coli vaccine on innate immune function of bovine mammary gland infused with lipopolysaccharide.  


The effects of using an enterotoxigenic Escherichia coli vaccine on innate immune responses following intramammary infusion of lipopolysaccharide (LPS) were investigated in midlactation Holstein-Friesian cows. Seven out of 14 cows were inoculated with E. coli vaccine. Three weeks later, 100 ?g of LPS dissolved in 10 mL of saline was infused into 1 quarter of all cows. Milk was collected every hour from infusion to 12 h after infusion, and twice daily (at 0900 and 1600 h) for 4 d. Blood samples were collected 0, 4, 8, 24, 48, 72, and 96 h after infusion. Rectal temperatures and milk yields were measured. The somatic cell count (SCC), lingual antimicrobial peptide concentration, lactoperoxidase (LPO) activity, and lactoferrin (LF) concentration in milk, and haptoglobin concentration in serum were determined. The mean rectal temperature in vaccinated cows was higher than in control cows at 10 h. The mean milk yield was decreased significantly in the infused quarter of control cows at 24 h compared with pretreatment, but not in vaccinated cows. The mean SCC in milk from vaccinated cows at 12 and 55 h was significantly lower than that of control cows. The lingual antimicrobial peptide and LF concentrations were significantly lower at 8 h and 55 h, respectively, in vaccinated cows than in control cows. The mean antibody titer in the serum against the vaccine at the time of LPS infusion into vaccinated cows was significantly higher than in control cows. These antibody titers were positively correlated with the peak concentrations of LPO and LF in milk following challenge; therefore, cows with a high antibody titer were accompanied by high LPO activity and LF concentration in milk. These results suggest that vaccination suppresses the innate immune reaction after intramammary LPS infusion; however, the elevated antibody titer was unlikely to be responsible for the modification of the innate immune reaction. PMID:22916910

Morimoto, K; Kanda, N; Shinde, S; Isobe, N



Phenotypic changes in the lipopolysaccharide of Pseudomonas aeruginosa and Escherichia coli grown in milk-based enteral nutrition solutions.  


Previous studies have shown enteral nutritional solutions (ENS) contaminated with large numbers of microorganisms from the environment or gastrointestinal (GI) tract of patients have caused respiratory infections, acute and chronic enteritis, and septicemia. The introduction of "closed" enteral feeding systems has been used to prevent contaminating organisms from entering enteral feeding systems in large numbers. However, there is some discussion as to whether this has been an effective measure in reducing ENS-related infections because there is anecdotal evidence to suggest that disease processes resulting from enteral feeding are still commonplace in the hospital and home. This is because there is very little information about the growth of microorganisms in ENS and whether growth in ENS may affect the virulence and pathogenicity of microorganisms. This study shows that Escherichia coli and Pseudomonas aeruginosa may grow at 25 degrees C from either high or low initial numbers to up to 9.2 log colony-forming units per mL in a range of milk-based ENS. However, these organisms did not grow in the fruit-based ENS. The effect on the lipopolysaccharide (LPS) of culturing E. coli and P. aeruginosa in milk-based ENS as opposed to standard laboratory media was examined using polyacrylamide gel electrophoresis. We found that there were significant qualitative changes in the phenotype of O-polysaccharide side chains of the LPS from these organisms. O-polysaccharide is known to mediate in the complement, antibiotic and bile resistance, and affect adherence. Therefore, changes in the virulence and pathogenicity of these microorganisms when cultured in ENS may be indicated. Thus, the study provides further evidence for reevaluating the microbiologic and immunologic effects of enteral feeding, especially on the microbial flora of the GI tract. PMID:9918056

Hodgson, I; Stewart, J; Fyfe, L



Effects of Escherichia coli Lipopolysaccharide on Telithromycin Pharmacokinetics in Rats: Inhibition of Metabolism via CYP3A?  

PubMed Central

It has been reported that telithromycin is metabolized primarily via hepatic microsomal cytochrome P450 (CYP) 3A1/2 in rats and that the expression of hepatic and intestinal CYP3A decreases in rats pretreated with Escherichia coli lipopolysaccharide (ECLPS rats; an animal model of inflammation). Thus, it is possible that the area under the plasma concentration-time curve from 0 h to infinity (AUC0-?) of intravenous and oral telithromycin is greater for ECLPS rats than for the controls. To assess this, the pharmacokinetic parameters of telithromycin were compared after intravenous and oral administration (50 mg/kg). After intravenous administration of telithromycin, the AUC0-? was significantly greater (by 83.4%) in ECLPS rats due to a significantly lower nonrenal clearance (by 44.5%) than in the controls. This may have been due to a significantly decreased hepatic metabolism of telithromycin in ECLPS rats. After oral administration of telithromycin, the AUC0-? in ECLPS rats was also significantly greater (by 140%) than in the controls and the increase was considerably greater than the 83.4% increase after intravenous administration. This could have been due to a decrease in intestinal metabolism in addition to a decreased hepatic metabolism of telithromycin in ECLPS rats.

Lee, Joo H.; Cho, Yu K.; Jung, Young S.; Kim, Young C.; Lee, Myung G.



In vivo endotoxin enhances biliary ethanol-dependent free radical generation.  


Endotoxemia is associated with alcoholic liver diseases; however, the effect of endotoxin on the oxidation of ethanol is not known. We tested the hypothesis that endotoxin treatment enhances hepatic ethanol radical production. The generation of free radicals by the liver was studied with spin-trapping technique utilizing the primary trap ethanol (0.8 g/kg) and the secondary trap alpha-(4-pyridyl-1-oxide)-N-t-butylnitrone (4-POBN; 500 mg/kg). Electron paramagnetic resonance (EPR) spectra of bile showed six-line signals, which were dependent on ethanol, indicating the trapping of ethanol-dependent radicals. Intravenous injections of Escherichia coli lipopolysaccharide (0.5 mg/kg) 0.5 h before 4-POBN plus ethanol treatment caused threefold increases of biliary radical adducts. EPR analyses of bile from [1-13C]ethanol-treated endotoxic rats showed the presence of species attributable to alpha-hydroxyethyl adduct, carbon-centered adducts, and ascorbate radical. The generation of endotoxin-induced increases of ethanol-dependent radicals was suppressed by 50% on GdCl3 (20 mg/kg i.v.) or desferrioxamine mesylate (1 g/kg i.p.) treatment. Our data show that in vivo endotoxin increases biliary ethanol-dependent free radical formation and that these processes are modulated by Kupffer cell activation and catalytic metals. PMID:9575846

Chamulitrat, W; Carnal, J; Reed, N M; Spitzer, J J



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.

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



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.

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.



Radiographic Evaluation of the Effect of Endotoxin (LPS) Plus Calcium Hydroxide on Apical and Periapical Tissues of Dogs  

Microsoft Academic Search

The aim of this study was the radiographic evalu- ation of the apical and periapical region of dog teeth submitted to intracanal bacterial endotoxin (lipopolysaccharide, LPS), associated or not with calcium hydroxide. After removal of the pulp, 60 premolars were divided into four groups and were filled with bacterial endotoxin (group 1), bacterial endotoxin plus calcium hydroxide (group 2), saline

Paulo Nelson-Filho; Mario Roberto Leonardo; Lea Assed Bezerra Silva


A comparison of the endotoxin biosynthesis and protein oxidation pathways in the biogenesis of the outer membrane of Escherichia coli and Neisseria meningitidis  

PubMed Central

The Gram-negative bacterial cell envelope consists of an inner membrane (IM) that surrounds the cytoplasm and an asymmetrical outer-membrane (OM) that forms a protective barrier to the external environment. The OM consists of lipopolysaccahride (LPS), phospholipids, outer membrane proteins (OMPs), and lipoproteins. Oxidative protein folding mediated by periplasmic oxidoreductases is required for the biogenesis of the protein components, mainly constituents of virulence determinants such as pili, flagella, and toxins, of the Gram-negative OM. Recently, periplasmic oxidoreductases have been implicated in LPS biogenesis of Escherichia coli and Neisseria meningitidis. Differences in OM biogenesis, in particular the transport pathways for endotoxin to the OM, the composition and role of the protein oxidation, and isomerization pathways and the regulatory networks that control them have been found in these two Gram-negative species suggesting that although form and function of the OM is conserved, the pathways required for the biosynthesis of the OM and the regulatory circuits that control them have evolved to suit the lifestyle of each organism.

Piek, Susannah; Kahler, Charlene M.



Alterations in the chemical composition and antigenicity of Escherichia coli O89 lipopolysaccharide and lipid A after 60Co gamma irradiation.  


The chemical composition and the antigenicity of Escherichia coli lipopolysaccharide (LPS) and lipid A were investigated after irradiation with 150 kGy 60Co-gamma ray. Compared to the original preparations, the irradiated LPS showed a significant reduction in glucosamine, glucose and galactose and a decrease in the phosphate content. The fatty acid components were reduced to a smaller degree. Irradiation induced a reduction in the antigenicity of the polysaccharide part. The amount of glucosamine and phosphate decreased in the irradiated lipid A. The fatty acid content was significantly reduced. The alteration in the chemical composition was not paralleled by changes in the antigenicity of irradiated lipid A. PMID:3067502

Elekes, E; Lüderitz, O; Galanos, C; Bertók, L



Lipid X ameliorates pulmonary hypertension and protects sheep from death due to endotoxin.  

PubMed Central

Lipid X (2,3-diacylglucosamine-1-phosphate) is a novel monosaccharide precursor of lipid A that has some of the physiologic activities of endotoxin but little toxicity. To determine whether lipid X would interfere with the toxic effects of endotoxin, we pretreated sheep with either 100 or 200 micrograms of lipid X per kg of body weight and then challenged them with a potentially fatal dose of Escherichia coli endotoxin (20 micrograms/kg). Twenty-one sheep underwent pulmonary artery catheterization and were monitored for changes in pulmonary artery pressure, temperature, pH, partial O2 pressure, partial CO2 pressure, blood pressure, and cell counts over 7 h. Overall mortality for control animals was 37% versus 5.3% for pretreated animals. None of the 13 animals pretreated with 100 micrograms of lipid X per kg died. These differences in survival were significant (P less than 0.05). Animals pretreated with 100 micrograms of lipid X per kg had significantly lower pulmonary artery pressure during both phases 1 and 2 of endotoxin-induced pulmonary artery hypertension. A higher dose of lipid X, 200 micrograms/kg, produced pulmonary hypertension. Perhaps because lipid X is a subunit of lipid A, lipid X shows a partial pyrogenic effect while also decreasing the pyrogenic activity of complete lipopolysaccharide (LPS). Lipid X did not prevent endotoxin-induced neutropenia or moderate hypotension in response to LPS. Lipid X is a potential prototype compound for a new type of chemotherapy directed at blocking the harmful effects of LPS during bacterial septicemia.

Golenbock, D T; Will, J A; Raetz, C R; Proctor, R A



Suppression of fibroblast growth by Bacteroides gingivalis endotoxin is not reduced by serum lipoproteins.  


Previous studies indicated that Bacteroides and E. coli endotoxins caused a dose-dependent inhibition of human fibroblast growth. However, these endotoxins were relatively weak inhibitors of growth. Since cells were grown with serum, we questioned whether serum lipoproteins, which lessen endotoxin cytotoxicity in vivo, reduced the growth inhibitory effects of endotoxins in vitro. To determine whether serum lipoproteins reduced the growth inhibitory effects of endotoxins, logarithmically growing human periodontal cells were incubated with endotoxin and high density (HDL) or low density lipoprotein (LDL). Neither HDL nor LDL significantly reduced the initial growth inhibitory effects of B. gingivalis or E. coli endotoxins, as judged by 3H-thymidine incorporation. Even with prolonged exposure of up to 10 days in culture, HDL did not ameliorate growth inhibition by endotoxin, as determined by direct cell counts. We conclude that serum lipoproteins do not provide any significant protective effects against fibroblast growth inhibition by endotoxins in vitro. PMID:2661804

Layman, D L; Landreneau, L A



Lipopolysaccharide-responder and nonresponder C3H mouse strains are equally susceptible to an induced Escherichia coli urinary tract infection.  

PubMed Central

Host defense against bacterial urinary tract infections (UTI) includes both inflammatory and immune responses to infecting bacteria. The cellular events leading up to local inflammation are thought to be under genetic control and initiated by lipopolysaccharides (LPS) of gram-negative bacteria such as Escherichia coli. It has been previously reported that mice which lack functional Lps genes are more susceptible to induced E. coli UTI than mice with normal mitogenic responses to LPS. In contrast to these findings, data in this report demonstrate that LPS-responder and nonresponder C3H mouse strains are equally susceptible to E. coli UTI. When C3H/OuJ (Lps(n)/Lps(n)) and C3H/HeJ (Lps(d)/Lps(d)) were intravesically inoculated with equal numbers of uropathogenic E. coli organisms, neither strain was able to effectively resolve the induced UTI. The inability of C3H/OuJ mice to combat the infection was not due to an impaired response to LPS, nor could defect in the local inflammatory response be identified. The results indicate that factors other than LPS responsiveness are also important in determining hose resistance to UTI.

Hopkins, W; Gendron-Fitzpatrick, A; McCarthy, D O; Haine, J E; Uehling, D T



Escherichia coli O157 fails to induce a long-lasting lipopolysaccharide-specific, measurable humoral immune response in children with hemolytic-uremic syndrome.  


Escherichia coli O157 lipopolysaccharide (LPS)-specific antibodies were measured in sequential serum samples from 131 children with serologically defined E. coli O157-associated hemolytic-uremic syndrome (HUS), using an enzyme immunoassay. On the basis of evaluation of 66 children with culture-proven E. coli O157 infection and serum samples from 132 age-matched control subjects, the assay showed a sensitivity of 95%, 88%, and 74% and a specificity of 99%, 99%, and 98% for IgM, IgA, and IgG, respectively. Anti-O157 LPS antibodies decreased below the cut-off levels in >50% of the children at 11 (IgM), 5 (IgA), and 11 weeks (IgG) after onset of diarrhea and 10, 4, and 10 weeks, respectively, after the onset of HUS. Children with enteropathic HUS fail to develop a long-lasting humoral immune response to the O157 antigen. Incomplete immunity to E. coli O157 may signal a risk for recurrent infections and has implications for serodiagnostic studies. PMID:12195387

Ludwig, Kerstin; Bitzan, Martin; Bobrowski, Christoph; Müller-Wiefel, Dirk E



Analysis of lipopolysaccharide biosynthesis in Salmonella typhimurium and Escherichia coli by using agents which specifically block incorporation of 3-deoxy-D-manno-octulosonate.  


Antibacterial agents which specifically inhibit CTP:CMP-3-deoxy-D-manno-octulosonate cytidylyltransferase activity were used to block the incorporation of 3-deoxy-D-manno-octulosonate (KDO) into lipopolysaccharide. Lipopolysaccharide synthesis ceased, molecules similar in structure to lipid A accumulated, and bacterial growth ceased following addition of such agents to cultures of Salmonella typhimurium and Escherichia coli. Although four major species of lipid A accumulated in S. typhimurium, their kinetics of accumulation were different. The least polar of the major species was IVA [O-(2-amino-2-deoxy-beta-D-glucopyranosyl)-(1----6)-2-amino-2-deoxy-a lph a- D-glucose, acylated at positions 2, 3, 2', and 3' with beta-hydroxymyristoyl groups and bearing phosphates at positions 1 and 4'], a molecule previously isolated from bacteria containing a kdsA mutation (C. R. H. Raetz, S. Purcell, M. V. Meyer, N. Qureshi, and K. Takayama, J. Biol. Chem. 260:16080-16088, 1985). Species IVA accumulated first and to the greatest extent following addition of the inhibitor, with other more polar derivatives appearing only after IVA attained half its maximal level. In contrast, only two major species of precursor accumulated in E. coli following addition of the inhibitor. One of these species was identical to IVA from S. typhimurium on the basis of chemical composition, fast atom bombardment mass spectroscopy, and comigration on Silica Gel H, and it also accumulated prior to a more polar species of related structure. We conclude that the addition of KDO to precursor species IVA is the major pathway of lipid A-KDO formation in both S. typhimurium LT2 and E. coli and that accumulation of the more polar species lacking KDO only occurs in response to accumulation of species IVA following inhibition of the normal pathway. PMID:2834331

Goldman, R C; Doran, C C; Capobianco, J O



Carbapenem-induced endotoxin release in Gram-negative bacterial sepsis rat models  

Microsoft Academic Search

The carbapenem-induced endotoxin release was evaluated using experimental models of Gram-negative bacterial sepsis in Wistar rats. Infections with Escherichia coli, Serratia marcescens, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus vulgaris and Proteus mirabilis resulted in an increase of the plasma endotoxin concentration after treatment with ceftazidime and carbapenems including imipenem, panipenem, meropenem and biapenem. Except for P. aeruginosa, the plasma endotoxin concentrations

Toshinobu Horii; Miya Kobayashi; Masayuki Nadai; Satoshi Ichiyama; Michio Ohta



Failure to protect Mice against Endotoxin with Snake Venom  

Microsoft Academic Search

WHEN bacterial exotoxin, endotoxin, or snake venom is injected intravenously into animals, peripheral vascular collapse occurs. Preliminary investigations demonstrated that the administration of sub-lethal doses of Escherichia coli, Salmonella typhi or brucella endotoxins protected mice against lethal doses of snake venoms (Crotalus terrificus and Bothrops jararaca). Since North and Doery1 have reported that the venom of the Australian tiger snake

Wesley W. Spink; Chancy K. Su



Alterations in Insulin Action by Endotoxin 'in vitro'.  

National Technical Information Service (NTIS)

Fat cells isolated from epididymal fat pads of Sprague-Dawley rats were exposed to E.coli endotoxin in vitro and after washing the ensuing alterations in glucose oxidation and antilipolysis studied. Although endotoxin (500 microgram/ml) exhibited an insul...

J. A. Spitzer D. C. Holley



Evaluation of inflammatory effects of airborne endotoxin emitted from composting sources.  


Because of the lack of effective methodology, the biological effects of environmental endotoxin have not been assessed. Here we have collected and measured airborne endotoxin at different locations around composting sites. Increased endotoxin concentrations were observed close to composting activities and also at nearby boundary areas. Analysis of proinflammatory effects of the environmental endotoxin on interleukin (IL)-8 and IL-6 release from human D562 pharyngeal epithelial and MM6 monocytic cell cultures showed an association between endotoxin level and cytokine induction. The cytokine-inducing effect of bioaerosol extracts was inhibited by polymyxin B, indicating that endotoxin was the cause of cytokine responses we found. The environmental endotoxin was also more active for stimulating cytokines in airway epithelial cells than commercially purified Escherichia coli endotoxin. Our results suggest that these in vitro inflammatory cell models may contribute to the assessment of health impacts of environmental endotoxin. PMID:21154847

Liu, Jian; Pankhurst, Louise J; Deacon, Lewis J; Abate, Wondwossen; Hayes, Enda T; Drew, Gill H; Longhurst, Phil J; Pollard, Simon; Longhurst, James; Tyrrel, Sean F; Jackson, Simon K



Modulation of HLA-DR antigens in the gingival epithelium in vitro by heat-killed Fusobacterium nucleatum and E. coli lipopolysaccharide.  


The in vitro influence of the periodontopathic organism Fusobacterium nucleatum (FN) on gingival tissue was examined using an organ culture system. Treatment of gingival explants obtained from periodontally diseased sites with suspensions of FN, stimulated the expression of HLA-DR antigens by Langerhans cells (LC) in a dose-dependent fashion, and produced a maintenance of the LC markers T6 and ATPase. Similar effects were seen when E. coli lipopolysaccharide (LPS) was substituted for suspensions of FN. With both FN and LPS the expression of HLA-DR by gingival keratinocytes was maintained throughout the 72-h culture period, despite the cytotoxic effects of these agents. Using a variety of immunohistological techniques and a monoclonal antibody specific for the strain of FN used, it was possible to demonstrate the uptake of FN antigens by LC within the gingival epithelium. PMID:2414424

Walsh, L J; Seymour, G J; Bird, P S; Powell, R N



Generation in plasma of a fast-acting inhibitor of plasminogen activator in response to endotoxin stimulation.  

PubMed Central

Endotoxin producing bacteria cause disseminated intravascular coagulation (DIC); however, the mechanism of endotoxin action in man is still unclear. Impairment of the fibrinolytic system has been suggested as a contributing mechanism. A single injection of Escherichia coli lipopolysaccharide in rabbits resulted in a marked and prolonged increase of the levels of a fast-acting inhibitor of plasminogen activator (PA-inhibitor) in plasma (from 3.9 +/- 0.7 to 41 +/- 13.2 U/ml after 3 h). Gel filtration studies indicated that inhibition of human tissue-type plasminogen activator (t-PA) by rabbit plasma is accompanied by a change in the elution profile of the activator compatible with the formation of an enzyme-inhibitor complex with an apparent molecular weight of 100,000. Injection of human t-PA (1,500 IU/kg body wt) in endotoxin treated animals resulted in very fast inhibition of t-PA and formation of a similar complex. The half-life of circulating PA-inhibitor activity in rabbits was about 7 min as estimated by donor receiver plasma transfusion experiments. Stimulation of cultured human endothelial cells with endotoxin resulted in enhanced rate of accumulation of PA-inhibitor activity in the culture medium (two- to sevenfold increase). In five patients with septicemia, markedly increased levels of PA-inhibitor (14.3 +/- 15.5 U/ml) as compared with control subjects (1.3 +/- 0.7 U/ml) were observed in plasma. A very strong correlation (r = 0.98) was found between inhibition of t-PA and of urokinase in all conditions, suggesting that this fast-acting inhibitor reacts with both plasminogen activators. These data suggest that the appearance of this fast-acting PA-inhibitor is very sensitive to endotoxin stimulation. The marked increase in the level of PA-inhibitor in blood may contribute to the pathogenesis of DIC in septicemia.

Colucci, M; Paramo, J A; Collen, D



The rfaE Gene from Escherichia coli Encodes a Bifunctional Protein Involved in Biosynthesis of the Lipopolysaccharide Core Precursor ADP-l-glycero-d-manno-Heptose  

PubMed Central

The intermediate steps in the biosynthesis of the ADP-l-glycero-d-manno-heptose precursor of inner core lipopolysaccharide (LPS) are not yet elucidated. We isolated a mini-Tn10 insertion that confers a heptoseless LPS phenotype in the chromosome of Escherichia coli K-12. The mutation was in a gene homologous to the previously reported rfaE gene from Haemophilus influenzae. The E. coli rfaE gene was cloned into an expression vector, and an in vitro transcription-translation experiment revealed a polypeptide of approximately 55 kDa in mass. Comparisons of the predicted amino acid sequence with other proteins in the database showed the presence of two clearly separate domains. Domain I (amino acids 1 to 318) shared structural features with members of the ribokinase family, while Domain II (amino acids 344 to 477) had conserved features of the cytidylyltransferase superfamily that includes the aut gene product of Ralstonia eutrophus. Each domain was expressed individually, demonstrating that only Domain I could complement the rfaE::Tn10 mutation in E. coli, as well as the rfaE543 mutation of Salmonella enterica SL1102. DNA sequencing of the rfaE543 gene revealed that Domain I had one amino acid substitution and a 12-bp in-frame deletion resulting in the loss of four amino acids, while Domain II remained intact. We also demonstrated that the aut::Tn5 mutation in R. eutrophus is associated with heptoseless LPS, and this phenotype was restored following the introduction of a plasmid expressing the E. coli Domain II. Thus, both domains of rfaE are functionally different and genetically separable confirming that the encoded protein is bifunctional. We propose that Domain I is involved in the synthesis of d-glycero-d-manno-heptose 1-phosphate, whereas Domain II catalyzes the ADP transfer to form ADP-d-glycero-d-manno-heptose.

Valvano, Miguel A.; Marolda, Cristina L.; Bittner, Mauricio; Glaskin-Clay, Mike; Simon, Tania L.; Klena, John D.



Evaluation of lipopolysaccharide aggregation by light scattering spectroscopy.  


Lipopolysaccharides (LPS) are cell wall components of Gram-negative bacteria. These molecules behave as bacterial endotoxins and their release into the bloodstream is a determinant of the development of a wide range of pathologies. These amphipathic molecules can self-aggregate into supramolecular structures with different shapes and sizes. The formation of these structures occurs when the LPS concentration is higher than the apparent critical micelle concentration (CMC(a)). Light scattering spectroscopy (both static and dynamic) was used to directly characterize the aggregation process of LPS from Escherichia coli serotype 026:B6. The results point to a CMC(a) value of 14 microg mL(-1) and the existence of premicelle LPS oligomers below this concentration. Both structures were characterized in terms of molecular weight (5.5 x 10(6) and 16 x 10(6) g mol(-1) below and above the CMC(a), respectively), interaction with the aqueous environment, gyration radius (56 and 105 nm), hydrodynamic radius, (60 and 95 nm) and geometry of the supramolecular structures (nearly spherical). Our data indicates that future in vitro experiments should be carried out both below and above the CMC(a). The search for drugs that interact with the aggregates, and thus change the CMC(a) and condition LPS interactions in the bloodstream, could be a new way to prevent certain bacterial-endotoxin-related pathologies. PMID:12512082

Santos, Nuno C; Silva, Ana C; Castanho, Miguel A R B; Martins-Silva, J; Saldanha, Carlota



Lipopolysaccharide neutralization by a novel peptide derived from phosvitin.  


Lipopolysaccharide (LPS), also known as endotoxin, is the primary trigger of sepsis, which is associated with high mortality in patients. No therapeutic agents are currently efficacious enough to protect patients from sepsis characterized by LPS-mediated tissue damage and organ failure. Previously, a phosvitin-derived peptide, Pt5, which consists of the C-terminal 55 residues of zebrafish phosvitin, has been shown to function as an antibacterial agent. In this study, we have generated six mutants by site-directed mutagenesis based on the sequence of Pt5, and found that one of the six mutants, Pt5e, showed the strongest bactericidal activities against Escherichia coli and Staphylococcus aureus. We then demonstrated that Pt5e was able to bind to LPS and lipoteichoic acid (LTA). More importantly, we showed that Pt5e significantly inhibited LPS-induced tumor-necrosis factor (TNF)-? and interleukin (IL)-1? release from murine RAW264.7 cells and considerably reduced serum TNF-? and IL-1? levels in mice. Additionally, Pt5e protected the liver from damage by LPS, and remarkably promoted the survival rate of the endotoxemia mice. Furthermore, Pt5e displayed no cytotoxicity to murine RAW264.7 macrophages and no hemolytic activity toward human red blood cells. These data together indicate that Pt5e is an endotoxin-neutralizing agent with a therapeutic potential in clinical treatment of LPS-induced sepsis. PMID:24028820

Hu, Lili; Sun, Chen; Wang, Shengnan; Su, Feng; Zhang, Shicui



A study on rat platelet responsiveness following intravenous endotoxin administration  

Microsoft Academic Search

The aim of the present study was to evaluate platelet responsiveness in rats following E.coli endotoxin administration. Injection of E.coli to rats caused a reduction in ADP-induced pulmonary 111In labelled platelet accumulation four hours later. Similarly, when platelet aggregation was evaluated on PRP obtained from rats four hours after endotoxin administration, we found that platelet response to both ADP and

Carla Cicala; Claudia Santacroce; Hidekazu Itoh; Garry J. Douglas; Clive P. Page




PubMed Central

Uridine diphosphate galactose 4-epimerase and phosphomannose isomerase-deficient mutants of Escherichia coli O111:B4 were studied to test the hypothesis that in E. coli a specific relationship exists between O antigenicity, virulence, and capacity to resist phagocytosis. The first mutant, designated J-5, produces a cell wall lipopolysaccharide, the side chains of which do not contain galactose, glucose, N-acetylglucosamine, or colitose. The second mutant produces a cell wall lipopolysaccharide which lacks only colitose. The capacity of these various organisms to kill mice was strikingly different. E. coli O111 was 1000 times as virulent as J-5, and 100 times as virulent as L-2. The capacity of the organisms to kill mice was correlated with their ability to resist phagocytosis and to persist in the peritoneal cavity. The parent strain of O111 resisted phagocytosis by macrophages in vivo and polymorphonuclear leukocytes in vitro. The mutants did not, and the organism most deficient in the saccharide component of its LPS was most susceptible to phagocytosis and least virulent. These results were corroborated by growing the mutants in appropriately supplemented media which permitted the synthesis of complete LPS, reversed the susceptibility to phagocytosis, and restored virulence. Finally, serological reactivity was consistent with previous observations which had demonstrated that the O antigenicity of E. coli is determined by the saccharide composition of its cell wall lipopolysaccharide. Despite the difference in the capacity of the various log-phase organisms to kill mice when injected intraperitoneally, purified lipopolysaccharides extracted from them did not differ significantly in their capacity to kill or produce fever. Thus virulence was shown to be independent of endotoxin activity which in turn seemed to be unrelated to the saccharide composition of the cell wall LPS. Collectively, these data provide at least a partial molecular definition of virulence in E. coli by demonstrating that the presence or absence of specific sugars in its cell wall lipopolysaccharide is a determinant of its antiphagocytic capacity and its virulence.

Medearis, Donald N.; Camitta, Bruce M.; Heath, Edward C.



The increased expression of proteins involved in proliferation, DNA repair and DNA methylation in spleen of mice exposed to E. coli O157:H7 lipopolysaccharide.  


Previous research showed that the consumption of heat-killed E. coli O157:H7 bacteria resulted in an increase in the level of DNA damage in intestine, liver and spleen cells. We hypothesized that certain bacterial components released from heat-killed bacteria trigger this response. We analysed the possibility that bacterial components [such as lipopolysaccharides (LPS)] could induce changes in the level of proteins involved in cell proliferation, DNA repair and DNA methylation in distal spleen tissues of mice. Four-week-old male mice were provided water supplemented with whole heat-killed E. coli O157:H7 bacteria or components of bacteria (DNA, RNA, proteins and LPS). Spleen cells responded to exposure to whole heat-killed bacteria and LPS with an alteration in the level of PCNA proteins, DNA methylation proteins (DNMT1, DNMT3A, DNMT3B, and MeCP2) and DNA repair proteins (APE1 and KU70). Other bacterial components analysed in this study mostly did not alter protein expression. The data suggest that LPS is a bacterial component capable of inducing molecular changes in naďve spleen cells of hosts exposed to it. PMID:23813549

Kovalchuk, Igor; Walz, Paul; Thomas, James; Kovalchuk, Olga



Pulmonary pharmacokinetics of tulathromycin in swine. Part I: Lung homogenate in healthy pigs and pigs challenged intratracheally with lipopolysaccharide of Escherichia coli.  


The objective of the study was to assess the pharmacokinetics of tulathromycin in lung tissue homogenate (LT) and plasma from healthy and lipopolysaccharide (LPS)-challenged pigs. Clinically healthy pigs were allocated to two dosing groups of 36 animals each (group 1 and 2). All animals were treated with tulathromycin (2.5 mg/kg). Animals in group 2 were also challenged intratracheally with LPS from Escherichia coli (LPS-Ec) 3 h prior to tulathromycin administration. Blood and LT samples were collected from all animals during 17-day post-tulathromycin administration. For LT, one sample from the middle (ML) and caudal lobes (CL) was taken. The concentration of tulathromycin was significantly lower in the ML after the intratracheal administration of LPS-E. coli (P < 0.02). In healthy pigs and LPS-challenged animals, the distribution of the drug into the lungs was rapid and persisted at high levels for 17-day postadministration. The distribution of the drug within the lung seems to be homogenous, at least between the middle and caudal lobes within dosing groups. The concentration versus time profile of the drug and pharmacokinetic parameters in two different lung areas (middle and caudal lobe) were consistent within the groups. The clinical significance of these findings is unknown. PMID:23072251

Villarino, N; Lesman, S; Fielder, A; García-Tapia, D; Cox, S; Lucas, M; Robinson, J; Brown, S A; Martín-Jiménez, T



Structural analysis of the lipid A isolated from Hafnia alvei 32 and PCM 1192 lipopolysaccharides.  


Hafnia alvei, a Gram-negative bacterium, is an opportunistic pathogen associated with mixed hospital infections, bacteremia, septicemia, and respiratory diseases. The majority of clinical symptoms of diseases caused by this bacterium have a lipopolysaccharide (LPS, endotoxin)-related origin. The lipid A structure affects the biological activity of endotoxins predominantly. Thus, the structure of H. alvei lipid A was analyzed for the first time. The major form, asymmetrically hexa-acylated lipid A built of beta-D-GlcpN4P-(1-->6)-alpha-D-GlcpN1P substituted with (R)-14:0(3-OH) at N-2 and O-3, 14:0(3-(R)-O-12:0) at N-2', and 14:0(3-(R)-O-14:0) at O-3', was identified by ESI-MS(n) and MALDI-time-of-flight (TOF) MS. Comparative analysis performed by MS suggested that LPSs of H. alvei 32, PCM 1192, PCM 1206, and PCM 1207 share the identified structure of lipid A. LPSs of H. alvei are yet another example of enterobacterial endotoxins having the Escherichia coli-type structure of lipid A. The presence of hepta-acylated forms of H. alvei lipid A resulted from the addition of palmitate (16:0) substituting 14:0(3-OH) at N-2 of the alpha-GlcpN residue. All the studied strains of H. alvei have an ability to modify their lipid A structure by palmitoylation. PMID:19706748

Lukasiewicz, Jolanta; Jachymek, Wojciech; Niedziela, Tomasz; Kenne, Lennart; Lugowski, Czeslaw



Bovine whole-blood culture as a tool for the measurement of endotoxin activities in Gram-negative bacterial vaccines.  


In order to analyze bovine immune reactions against the Gram-negative bacterial vaccine, bovine whole-blood culture was used to investigate the pro-inflammatory cytokine responses stimulated with lipopolysaccharides (LPS) extracted from Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa, and Klebsiella pneumoniae. We also examined the interaction between LPS and aluminum hydroxide gel for endotoxin activity and pro-inflammatory cytokine responses of whole bovine blood. Alteration in the mRNA concentrations of tumor necrosis factor (TNF)-?, interleukin (IL)-1?, and IL-10 in whole-blood culture at 4h after stimulation with different doses of LPS was observed and determined by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The mRNA concentrations of TNF-? and IL-1? changed in a dose-dependent manner and differed depending on the type of LPS. Limulus test revealed that endotoxin activity was remarkably reduced when aluminum hydroxide gel was added to LPS. In contrast, the mRNA concentration of TNF-? in whole bovine blood was enhanced by LPS mixed with aluminum hydroxide gel. These results suggest that bovine whole-blood culture can be utilized to detect endotoxin activity of Gram-negative bacterial vaccines. In addition, whole-blood culture offers several advantages, such as ease of performance, few preparation artifacts, and a physiological cell environment, for investigating bovine immune response compared with the Limulus test. PMID:23465356

Imamura, Saiki; Nakamizo, Mari; Kawanishi, Michiko; Nakajima, Nao; Yamamoto, Kinya; Uchiyama, Mariko; Hirano, Fumiya; Nagai, Hidetaka; Kijima, Mayumi; Ikebuchi, Ryoyo; Mekata, Hirohisa; Murata, Shiro; Konnai, Satoru; Ohashi, Kazuhiko



Effects of Lipopolysaccharide, Lipid A, Lipid X, and Phorbol Ester on Cultured Bovine Endothelial Cells,  

National Technical Information Service (NTIS)

In pursuing the mechanism of endotoxin action, we examined the effect of lipopolysaccharide (LPS) and its chemically defined components, lipid A and lipid X on cultured bovine endothelial cells. We report that LPS and lipid A caused detachment and altered...

S. L. Gartner D. G. Sieckmann Y. H. Kang L. P. Watson L. D. Homer



Distribution and Role of Lipopolysaccharide in the Pathogenesis of Acute Renal Proximal Tubule Injury.  

National Technical Information Service (NTIS)

Endotoxins (lipopolysaccharides; LPS) are known to cause multiple organ failure, including renal dysfunction. The present report elucidates LPS distribution and effect on renal proximal tubules in an attempt to gain a better understanding of the cellular ...

Y. H. Kang M. C. Falk T. B. Bentley C. H. Lee



Exacerbation of Alcoholic Liver Injury by Enteral Endotoxin in Rats  

Microsoft Academic Search

Increased gut permeability (leaky gut) and endotoxin-mediated Kupffer cell activation are proposed as the mechanisms of alcoholic liver injury. Although ethanol feeding is shown to sensitize the liver for injury induced by parental administration of lipopolysaccharide (LPS), how enteral LPS loading affects alcoholic liver injury is yet to be tested. The present study provides direct evidence for enhanced entrance to

Philippe Mathurin; Qing-Gao Deng; Ali Keshavarzian; Sandeep Choudhary; Earle W. Holmes; Hidekazu Tsukamoto



Antipyretic effect of neuropeptide galanin in endotoxin-induced fever.  


Neuropeptide galanin produces a antipyretic effect in experimental pyrogenic reaction induced by intraperitoneal injection of lipopolysaccharide. Central intracerebroventricular injection of 100 ng galanin significantly attenuated, but did not completely abolish fever. Central galanin injection potentiated endotoxin-induced activation of the noradrenergic system and blocked activation of the serotoninergic system of the anterior hypothalamus. PMID:11329085

Lyudyno, V I; Krasnova, I N; Smirnova, M P; Klimenko, V M



A probiotic strain of Escherichia coli, Nissle 1917, given orally exerts local and systemic anti-inflammatory effects in lipopolysaccharide-induced sepsis in mice  

PubMed Central

Background and purpose: Escherichia coli Nissle 1917 is a probiotic strain used in the treatment of intestinal immune diseases, including ulcerative colitis. The aim of the present study was to test if this probiotic bacterium can also show systemic immunomodulatory properties after oral administration. Experimental approach: The probiotic strain was administered to rats or mice for 2 weeks before its assay in two experimental models of altered immune response, the trinitrobenzenesulphonic acid (TNBS) model of rat colitis, localized in the colon, and the lipopolysaccharide (LPS) model of systemic septic shock in mice. Inflammatory status was evaluated both macroscopically and biochemically after 1 week in the TNBS model or after 24 h in the LPS shock model. In addition, splenocytes were obtained from mice and stimulated, ex vivo, with concanavalin A or LPS to activate T or B cells, respectively, and cytokine production (IL-2, IL-5 and IL-10) by T cells and IgG secretion by B cells measured. Key results: E. coli Nissle 1917 was anti-inflammatory in both models of altered immune response. This included a reduction in the pro-inflammatory cytokine tumour necrosis factor-? both in the intestine from colitic rats, and in plasma and lungs in mice treated with LPS. The systemic beneficial effect was associated with inhibited production of the T cell cytokines and by down-regulation of IgG release from splenocyte-derived B cells. Conclusions and implications: The anti-inflammatory effects of E. coli Nissle 1917 given orally were not restricted to the gastrointestinal tract.

Arribas, B; Rodriguez-Cabezas, ME; Camuesco, D; Comalada, M; Bailon, E; Utrilla, P; Nieto, A; Concha, A; Zarzuelo, A; Galvez, J



Continuous infusion of Escherichia coli endotoxin in vivo primes in vitro superoxide anion release in rat polymorphonuclear leukocytes and Kupffer cells in a time-dependent manner.  

PubMed Central

Continuous infusion of a nonlethal dose of Escherichia coli lipopolysaccharide (LPS) (0.5 mg/kg) induced early (3 h) accumulation of polymorphonuclear leukocytes (PMNL) in rat liver followed by later (30 h) greater extravasation of mononuclear phagocytes (MNP) (E. B. Rodriguez de Turco and J. A. Spitzer, J. Leukocyte Biol. 48:488-494, 1990). Nonparenchymal liver cells from rats treated for 3 and 30 h with LPS were recovered by centrifugal elutriation, yielding a 23-ml/min fraction (endothelial cells) and a 45-ml/min fraction (PMNL, Kupffer cells, and MNP), and compared for their capacity for basal and agonist-stimulated superoxide (O2-) production. Stimulation with phorbol myristate acetate and opsonized zymosan caused a dose-dependent release of O2- from the 45-ml/min fraction derived from rats treated for 3 h with saline, but not from the 23-ml/min fraction. Further purification of the 45-ml/min fraction by discontinuous density gradient centrifugation into a Kupffer and a PMNL fraction revealed that most of the agonist-induced O2- release was generated by infiltrating PMNL at this early time point of LPS infusion. By 30 h of LPS infusion, although enhancement of the phorbol-12-myristate-13-acetate- and opsonized zymosan-stimulated release of O2- was observed in the 45-ml/min fraction, but not in the 23-ml/min fraction, the maximum release of O2- was smaller than that observed in the rats treated for 3 h. Our results support the following conclusions: (i) after a 3-h LPS infusion, PMNL found in the liver in increased numbers are also highly primed for agonist-stimulated release of O2-, while Kupffer cell priming is of a lesser extent; (ii) after a 30-h infusion of LPS, infiltrating MNP found in the liver in increased numbers are primed for agonist-induced O2- release, while priming of PMNL has diminished; (iii) at both 3 and 30 h of LPS infusion, liver endothelial cells are not significantly primed for agonist-stimulated O2- release; and (iv) in vivo priming by LPS infusion at both 3 and 30 h was not reversed by the experimental method used for cell recovery (ca. 3 h), thus suggesting that in vivo LPS priming of O2- release may ultimately lead to severe impairment of liver function and metabolism observed during endotoxemia and sepsis if not therapeutically blocked at an early time point.

Mayer, A M; Spitzer, J A



Importance of a Lipopolysaccharide-Initiated, Cytokine-Mediated Host Defense Mechanism in Mice against Extraintestinally Invasive Escherichia coli.  

National Technical Information Service (NTIS)

Extraintestinally invasive Eschenchta coli (EC) that possess strains retrieved from patients with bacterem both a complete LPS and Ki capsule evade both completement -mediated bacteriolysis and neutrophil-mediated killing. Since C3H/HeJ mice that are hypo...

A. Cross L. Asher M. Seguin L. Yuan N. Kelly



Characterization of Lipopolysaccharides Present in Settled House Dust  

Microsoft Academic Search

The 3-hydroxy fatty acids (3-OHFAs) in lipopolysaccharides (LPS) play an important role in determining endotoxin activity, and childhood exposure to endotoxin has recently been associated with reduced risk of atopic diseases. To characterize the 3-OHFAs in house dust (HD), we used gas chromatography-mass spec- trometry to assay 190 HD samples. Dust from beds, bedroom floors, family rooms, and kitchen floors

Ju-Hyeong Park; Bogumila Szponar; Lennart Larsson; Diane R. Gold; Donald K. Milton



Contamination of nanoparticles by endotoxin: evaluation of different test methods  

PubMed Central

Background Nanomaterials can be contaminated with endotoxin (lipopolysaccharides, LPS) during production or handling. In this study, we searched for a convenient in vitro method to evaluate endotoxin contamination in nanoparticle samples. We assessed the reliability of the commonly used limulus amebocyte lysate (LAL) assay and an alternative method based on toll-like receptor (TLR) 4 reporter cells when applied with particles (TiO2, Ag, CaCO3 and SiO2), or after extraction of the endotoxin as described in the ISO norm 29701. Results Our results indicate that the gel clot LAL assay is easily disturbed in the presence of nanoparticles; and that the endotoxin extraction protocol is not suitable at high particle concentrations. The chromogenic-based LAL endotoxin detection systems (chromogenic LAL assay and Endosafe-PTS), and the TLR4 reporter cells were not significantly perturbed. Conclusion We demonstrated that nanoparticles can interfere with endotoxin detection systems indicating that a convenient test method must be chosen before assessing endotoxin contamination in nanoparticle samples.



Role of lipopolysaccharide in assembly of Escherichia coli outer membrane proteins OmpA, OmpC, and OmpF.  

PubMed Central

Selection was performed for resistance to a phage, Ox2, specific for the Escherichia coli outer membrane protein OmpA, under conditions which excluded recovery of ompA mutants. All mutants analyzed produced normal quantities of OmpA, which was also normally assembled in the outer membrane. They had become essentially resistant to OmpC and OmpF-specific phages and synthesized these outer membrane porins at much reduced rates. The inhibition of synthesis acted at the level of translation. This was due to the presence of lipopolysaccharides (LPS) with defective core oligosaccharides. Cerulenin blocks fatty acid synthesis and therefore that of LPS. It also inhibits synthesis of OmpC and OmpF but not of OmpA (C. Bocquet-Pagčs, C. Lazdunski, and A. Lazdunski, Eur. J. Biochem. 118:105-111, 1981). In the presence of the antibiotic, OmpA synthesis and membrane incorporation remained unaffected at a time when OmpC and OmpF synthesis had almost ceased. The similarity of these results with those obtained with the mutants suggests that normal porin synthesis is not only interfered with by production of mutant LPS but also requires de novo synthesis of LPS. Since synthesis and assembly of OmpA into the outer membrane was not affected in the mutants or in the presence of cerulenin, association of this protein with LPS appears to occur with outer membrane-located LPS. Images

Ried, G; Hindennach, I; Henning, U



Genetic analysis of lipopolysaccharide core biosynthesis by Escherichia coli K-12: insertion mutagenesis of the rfa locus.  

PubMed Central

Tn10 insertions were selected on the basis of resistance to the lipopolysaccharide (LPS)-specific bacteriophage U3. The majority of these were located in a 2-kilobase region within the rfa locus, a gene cluster of about 18 kb that contains genes for LPS core biosynthesis. The rfa::Tn10 insertions all exhibited a deep rough phenotype that included hypersensitivity to hydrophobic antibiotics, a reduction in major outer membrane proteins, and production of truncated LPS. These mutations were complemented by a Clarke-Carbon plasmid known to complement rfa mutations of Salmonella typhimurium, and analysis of the insert from this plasmid showed that it contained genes for at least six polypeptides which appear to be arranged in the form of a complex operon. Defects in two of these genes were specifically implicated as the cause of the deep rough phenotype. One of these appeared to be rfaG, which encodes a function required for attachment of the first glucose residue to the heptose region of the core. The other gene did not appear to be directly involved in determination of the sugar composition of the core. We speculate that the product of this gene is involved in the attachment of phosphate or phosphorylethanolamine to the core and that it is the lack of one of these substituents which results in the deep rough phenotype. Images

Austin, E A; Graves, J F; Hite, L A; Parker, C T; Schnaitman, C A



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



Hemoglobin increases mortality from bacterial endotoxin.  

PubMed Central

Cell-free hemoglobin (Hb) is being developed as an erythrocyte substitute. We have previously demonstrated that cell-free Hb is an endotoxin-binding protein which disaggregates endotoxin and subsequently increases the biological activity of endotoxin in several in vitro assays. Because much of the morbidity and mortality associated with gram-negative bacterial infection is the result of pathophysiologic responses to bacterial lipopolysaccharide (LPS; endotoxin), we studied the effect of Hb on LPS-mediated mortality. Hb infused intravenously into mice before, coincident with, or after intraperitoneal LPS injection substantially increased LPS-related mortality from <5% to 50 to 70% 24 h after administration of LPS and from 50% to 60 to 90% at 48 h. Enhanced mortality was observed over a range of doses of injected LPS. At a given LPS dose, enhancement of mortality was shown to be dependent on the dose of Hb administered. Unmodified native human Hb, alpha-alpha-cross-linked human Hb, and beta-beta-cross-linked human or bovine Hb all were shown to enhance LPS-mediated mortality. Depressed reticuloendothelial cell function may have contributed to the enhanced mortality from LPS in the presence of Hb. Therefore, Hb-based blood substitutes, which are currently undergoing clinical trials, may intensify the potentially fatal effects of the sepsis syndrome in patients with trauma, infection, or hypotension who receive Hb for erythrocyte replacement.

Su, D; Roth, R I; Yoshida, M; Levin, J



Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and monoclonal antibodies as tools for the subgrouping of Escherichia coli lipopolysaccharide O18 and O23 antigens.  

PubMed Central

The lipopolysaccharide (LPS) of Escherichia coli O18 isolated from a wide variety of sources was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Four different LPS types, designated O18A, O18A1, O18B, and O18B1, were identified. Most O18 strains possess O18A, O18A1, or O18B LPS types, and these types are clonally associated. A reference test strain with the classical O18ab designation possessed O18B LPS, while two reference O18ac strains possessed O18A and O18A1 LPS, respectively. A panel of 15 anti-O18A B-cell hybridomas was isolated. Enzyme-linked immunosorbent assays revealed that some of the monoclonal antibodies produced by these cells recognize different epitopes. Four of these antibodies suffice to distinguish the four O18 types. Numerous strains whose LPS had been typed by SDS-PAGE were tested by agglutination with seven monoclonal antibodies whose specificities had been determined by enzyme-linked immunosorbent assays. The results indicated a perfect correlation between the two methods. Rabbit antisera raised against O18A bacteria agglutinated boiled bacteria of each of the O18 LPS types efficiently. The antisera were adsorbed with bacteria possessing each of the LPS types. The adsorbed sera only distinguished between two groups: O18A and O18A1 versus O18B and O18B1, as shown by agglutination assays and Western blotting. E. coli O4 and O23 and Serratia marcescens O8 antigens, which are reputed to cross-react with O18, were also analyzed. One O4, one O8, and four O23 strains were tested. All made an LPS which was distinguishable from O18 LPS types by SDS-PAGE. Each O23 strain synthesized a different LPS, and three of them synthesized only few short chains. Some of the monoclonal antibodies reacted with O4, O8, and O23A LPSs. The results are interpreted as indicating that numerous E. coli O serogroups will prove to be chemically heterogeneous and that future analyses of subgroup heterogeneity should be guided by results from SDS-PAGE and rely preferentially on monoclonal antibodies as opposed to rabbit hyperimmune sera. Images

Pluschke, G; Moll, A; Kusecek, B; Achtman, M



Purification of lipopolysaccharide-binding protein from bovine serum  

Microsoft Academic Search

Lipopolysaccharide-binding protein (LBP) plays a central role in presentation of bacterial-derived lipopolysaccharide (LPS; endotoxin) to leukocytes such as macrophages and neutrophils. Interaction of LBP with LPS is significant because LBP-LPS complexes promote activation of leukocytes and the immune system, which results in enhanced secretion of a spectrum of proinflammatory cytokines. An improved, simplified method was used to purify bovine LBP

Philip N. Bochsler; Zhengang Yang; Charles L. Murphy; Roger C. Carroll



Purification and characterization of an endotoxin-binding protein with protease inhibitory activity from Limulus amebocytes.  


Using a lipopolysaccharide affinity column and ion exchange chromatography, a 12-kDa protein has been purified from Limulus amebocytes. In solid phase binding assays, the radiolabeled protein binds specifically to lipopolysaccharide (LPS) with a Kd value on the order of 10(-7) M. A cDNA coding for this protein has been isolated and sequenced. The amino acid sequence deduced from the cDNA indicates that this protein shares no sequence homology with LPS-binding proteins isolated from different species of vertebrates (Schumann, R. R., Leong, S. R., Flaggs, G. W., Gray, P. W., Wright, S. D., Mathison, J. C., Tobias, P. S., and Ulevitch, R. J. (1990) Science 249, 1429-1431) and invertebrates (Aketagawa, J., Miyata, T., Ohtsubo, S., Nakamura, T., Morita, T., Hayashida, H., Miyata, T., Iwanaga, S., Takao, T., and Shimonishi, Y. (1986) J. Biol. Chem. 261, 7357-7365). The binding to LPS can be displaced by the unlabeled 12-kDa protein, polymyxin B, lipid A, and to a lesser extent by D-glucosamine. In whole cell binding assays, the 12-kDa protein has also been shown to bind to Escherichia coli. Using both [14C]casein and a synthetic substrate, the protein has been shown to inhibit the proteolytic activity of trypsin, with an IC50 of approximately 10(-7) M. In the presence of LPS, the antitryptic acitivity of the Limulus endotoxin-binding protein-protease inhibitor remains unaffected. The protein is a major component of the cytoplasmic proteins (1%). Immunocytochemical analysis reveals that this protein exists in the secretory granules of the amebocytes where enzymes and substrates for the clotting cascade reside. Based on the unusual dual functional properties, the newly isolated protein was named a "Limulus endotoxin-binding protein-protease inhibitor" (LEBP-PI). PMID:1939127

Minetti, C A; Lin, Y A; Cislo, T; Liu, T Y



Rapid up-regulation of endothelial nitric-oxide synthase in a mouse model of Escherichia coli lipopolysaccharide-induced bladder inflammation.  


Increases in the signaling molecule nitric oxide (NO) during inflammation may be linked not only to inducible nitric-oxide synthase (iNOS) but also to endothelial (e)NOS. Escherichia coli lipopolysaccharide (LPS) induces an inflammatory response in the bladder and rapidly increases phosphorylation of Akt/protein kinase B (Akt), a key enzyme regulating proliferation, apoptosis, and inflammation. Activated Akt phosphorylates human eNOS at serine 1177 and subsequently increases NOS activity. Because Akt and eNOS are both localized in the bladder urothelium, phosphorylation of eNOS by Akt provides an attractive mechanism for rapid increases in urinary NO production. Female mice were intraperitoneally injected with LPS (25 mg/kg) or pyrogen-free water (control). Four hours before LPS injection, some mice were injected with wortmannin, which inhibits Akt phosphorylation. Levels of urinary cyclic GMP, a downstream product of NO, increase 75% within 1 h after intraperitoneal injection of LPS, and this increase is blocked by wortmannin. Bladder eNOS and phosphorylated eNOS protein increase 94 and 151%, respectively, 1 h after LPS treatment, whereas iNOS was not detected. Wortmannin decreases eNOS phosphorylation by 60%. Furthermore, bladder Ca(2+)-dependent NOS activity (eNOS, neuronal NOS) is increased 79 +/- 20% 1 h after LPS treatment, whereas there is no increase in Ca(2+)-independent (iNOS) activity (n = 4). Increases in urinary cyclic GMP, NOS activity, and eNOS protein and phosphorylation 1 h after induction of inflammation with LPS, indicate that eNOS plays a role in the early response to bladder inflammation. PMID:15082754

Kang, Walter S; Tamarkin, Frank J; Wheeler, Marcia A; Weiss, Robert M



In vivo protection against endotoxin by plasma high density lipoprotein.  

PubMed Central

Overwhelming bacterial infection is accompanied by fever, hypotension, disseminated intravascular coagulation, and multiple organ failure leading to death in 30-80% of cases. These classical symptoms of septic shock are caused by potent cytokines that are produced in response to endotoxin released from Gram-negative bacteria. Treatments with antibodies and receptor antagonists to block endotoxin or cytokine mediators have given mixed results in clinical trials. High density lipoprotein (HDL) is a natural component of plasma that is known to neutralize endotoxin in vitro. We report here that raising the plasma HDL concentration protects mice against endotoxin in vivo. Transgenic mice with 2-fold-elevated plasma HDL levels had more endotoxin bound to HDL, lower plasma cytokine levels, and improved survival rates compared with low-HDL mice. Intravenous infusion of HDL also protected mice, but only when given as reconstituted HDL prepared from phospholipid and either HDL apoprotein or an 18-amino acid peptide synthesized to mimic the structure of apolipoprotein A-I of HDL. Intact plasma HDL was mildly toxic, and HDL apoprotein was ineffective. The effectiveness of the reconstituted peptide renders very unlikely any significant contribution to protection by trace proteins in apo-HDL. These data suggest a simple leaflet insertion model for binding and neutralization of lipopolysaccharide by phospholipid on the surface of HDL. Plasma HDL may normally act to protect against endotoxin; this protection may be augmented by administration of reconstituted HDL or reconstituted peptides. Images Fig. 1 Fig. 2 Fig. 3

Levine, D M; Parker, T S; Donnelly, T M; Walsh, A; Rubin, A L



The importance of a lipopolysaccharide-initiated, cytokine-mediated host defense mechanism in mice against extraintestinally invasive Escherichia coli.  

PubMed Central

Extraintestinally invasive Escherichia coli (EC) that possess both a complete LPS and K1 capsule evade both complement-mediated bacteriolysis and neutrophil-mediated killing. Since C3H/HeJ mice that are hyporesponsive to LPS were uniquely susceptible to lethal infection with EC of this phenotype, we speculated there was an LPS-initiated host defense mechanism against this pathogenic phenotype. The LPS-normoresponsive C3H/HeN as well as the C3H/HeJ mice cleared these EC from the circulation within 4 h of intravenous administration. Whereas electron micrographs of the liver demonstrated these EC undergoing degeneration within the phagolysosomes of of both macrophages and Kupffer cells of C3H/HeN mice, these EC replicated within these cells of the C3H/HeJ mice. Restoration of anti-EC activity of C3H/HeJ mice occurred with activation of Kupffer cells and peritoneal macrophages in vivo with BCG and in vitro with IFN-gamma, but not with LPS. Pretreatment of C3H/HeJ mice with a combination of recombinant murine IL-1 and TNF-alpha also restored the killing of K1(+)-EC but did not enhance the killing of a K1(-)-EC mutant. These data are consistent with the hypothesis that (a) there is no intrinsic inability of C3H/HeJ phagocytes to kill EC, but (b) an LPS-initiated, cytokine-mediated host defense mechanism is required for such killing. These studies emphasize the importance of bacterial surface characteristics in the interaction with specific host defenses. Images

Cross, A; Asher, L; Seguin, M; Yuan, L; Kelly, N; Hammack, C; Sadoff, J; Gemski, P



Relative potencies of four reference endotoxin standards as measured by the Limulus amoebocyte lysate and USP rabbit pyrogen tests.  

PubMed Central

Four commonly used reference endotoxin standards, Escherichia coli O113:H10:K0, E. coli O55:B5, Salmonella abortusequi, and Shigella dysenteriae were compared by the USP rabbit pyrogen and the Limulus amoebocyte lysate tests. By the rabbit pyrogen test, S. abortus equi was identified as the most potent endotoxin, followed closely by E. coli O113:H10:K0 and E. coli O55:B5.

Weary, M E; Donohue, G; Pearson, F C; Story, K



Core-Specific Receptors for Lipopolysaccharide on Hepatocytes,  

National Technical Information Service (NTIS)

The liver has been known to be the principal organ involved in the clearance of endotoxin (lipopolysaccharide, LPS) from the systemic circulation. The uptake of LPS by the liver is rapid, extensive and of apparent high affinity. The identity of the hepati...

J. B. Parent



Binding of /sup 125/I-labeled endotoxin to bovine, canine, and equine platelets and endotoxin-induced agglutination of canine platelets  

SciTech Connect

Endotoxin from Escherichia coli O127:B8, Salmonella abortus-equi and S minnesota induced clumping of some canine platelets (PLT) at a final endotoxin concentration of 1 microgram/ml. Endotoxin-induced clumping of canine PLT was independent of PLT energy-requiring processes, because clumping was observed with canine PLT incubated with 2-deoxy-D-glucose and antimycin A. The PLT responded to adenosine diphosphate before, but not after, incubation with the metabolic inhibitors. Endotoxin induced a slight and inconsistant clumping of bovine and equine PLT at high (mg/ml) endotoxin concentration. High-affinity binding sites could not be demonstrated on canine, bovine, and equine PLT, using /sup 125/I-labeled E coli O127:B8 endotoxin. Nonspecific binding was observed and appeared to be due primarily to an extraneous coat on the PLT surface that was removed by gel filtration. The endotoxin that was bound to PLT did not appear to modify PLT function. An attempt to identify plasma proteins that bound physiologically relevant amounts of endotoxin was not successful. The significance of the endotoxin-induced clumping or lack of it on the pathophysiology of endotoxemia is discussed.

Meyers, K.M.; Boehme, M.; Inbar, O.



Effect of endotoxin on heart rate dynamics in rats with cirrhosis.  


Reduced heart rate variability (HRV) is a hallmark of systemic inflammation which carries negative prognostic information in sepsis. Decreased HRV is associated with partial uncoupling of cardiac pacemaker from cholinergic neural control during systemic inflammation. Sepsis is a common complication in liver cirrhosis with high mortality. The present study was aimed to explore the hypothesis that endotoxin uncouples cardiac pacemaker from autonomic neural control and reduces HRV in an experimental model of cirrhosis. Cirrhosis was induced by surgical ligation of the bile duct in rats. Cirrhotic rats were given intraperitoneal injection of either saline or lipopolysaccharide (endotoxin, 1mg/kg). Changes in HRV indices were studied in conscious rats using implanted telemetric probes. The atria were isolated and chronotropic responsiveness to cholinergic stimulation was assessed in vitro. Endotoxin injection induced a significant tachycardia and decreased short-term and long-term HRV indices in control rats. However, endotoxin was unable to increase heart rate in cirrhotic animals. In contrast with control rats, endotoxin induced biphasic changes in short-term HRV in cirrhotic rats. Acute endotoxin challenge reduced long-term HRV with 60-min delay in comparison with control animals. Endotoxin injection was associated with a significant hypo-responsiveness to cholinergic stimulation in control rats in vitro. Endotoxin did not change atrial chronotropic responsiveness to cholinergic stimulation in cirrhotic rats. Our data shows that cirrhosis is associated with development of tolerance to cardiac chronotropic effect of endotoxin in rats. PMID:23511062

Haddadian, Zahra; Eftekhari, Golnar; Mazloom, Roham; Jazaeri, Farahnaz; Dehpour, Ahmad R; Mani, Ali R



Insulin Action and Binding Kinetics in Adipocytes Exposed to Endotoxin 'in vitro' and 'in vivo'.  

National Technical Information Service (NTIS)

The in vitro and in vivo effects of E. coli endotoxin were investigated on rat adipocytes in terms of oxidation of U-14C-glucose and insulin binding kinetics. Isolated adipocytes exposed to endotoxin (500 microgram/ml) in vitro demonstrated a 48% increase...

D. C. Holley J. A. Spitzer



Effects of endotoxin on mammary secretion of lactating goats.  


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 .1 microgram of endotoxin; .25 microgram produced changes in most of the other parameters; maximal effect was elicited by 1 microgram 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 [14C]lactose into the gland and [99mTc]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. PMID:3522681

Lengemann, F W; Pitzrick, M



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.



Promoter Region of the Escherichia coli O7-Specific Lipopolysaccharide Gene Cluster: Structural and Functional Characterization of an Upstream Untranslated mRNA Sequence  

PubMed Central

We report the identification of the promoter region of the Escherichia coli O7-specific lipopolysaccharide (LPS) gene cluster (wbEcO7). Typical ?10 and ?35 sequences were found to be located in the intervening region between galF and rlmB, the first gene of the wbEcO7 cluster. Data from RNase protection experiments revealed the existence of an untranslated leader mRNA segment of 173 bp, including the JUMPStart and two ops sequences. We characterized the structure of this leader mRNA by using the program Mfold and a combination of nested and internal deletions transcriptionally fused to a promoterless lac operon. Our results indicated that the leader mRNA may fold into a series of complex stem-loop structures, one of which includes the JUMPStart element. We have also found that one of the ops sequences resides on the predicted stem and the other resides on the loop region, and we confirmed that these sequences are essential for the RfaH-mediated regulation of the O polysaccharide cluster. A very similar stem-loop structure could be predicted in the promoter region of the LPS core operon encoding the waaQGPSBIJYZK genes. We observed another predicted stem-loop, located immediately downstream from the wbEcO7 transcription initiation site, which appeared to be involved in premature termination of transcription. This putative stem-loop is common to many other O polysaccharide gene clusters but is not present in core oligosaccharide genes. wbEcO7-lac transcriptional fusions in single copy numbers were also used to determine the effects of various environmental cues in the transcriptional regulation of O polysaccharide synthesis. No effects were detected with temperature, osmolarity, Mg2+ concentration, and drugs inducing changes in DNA supercoiling. We therefore conclude that the wbEcO7 promoter activity may be constitutive and that regulation takes place at the level of elongation of the mRNA in a RfaH-mediated manner.

Marolda, Cristina L.; Valvano, Miguel A.



IL18-deficient mice are resistant to endotoxin-induced liver injury but highly susceptible to endotoxin shock  

Microsoft Academic Search

IL-18 is an IL-1-related cytokine which shares biological functions with IL-12. These include the activation of NK cells, induction of IFN-g production and Th1 cell differentiation. In this study we analyzed the effect of IL-18 deficiency on lipopolysaccharide (LPS)-induced liver injury and endotoxin shock in Propionibacterium acnes-primed mice. P. acnes-primed IL-18-deficient (IL-18KO) mice showed resistance to LPS-induced liver injury. Unexpectedly,

Yoshimitsu Sakao; Kiyoshi Takeda; Hiroko Tsutsui; Tsuneyasu Kaisho; Fumiko Nomura; Haruki Okamura; Kenji Nakanishi; Shizuo Akira



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.

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



Removing Endotoxin from Metallic Biomaterials with Compressed Carbon Dioxide-Based Mixtures  

PubMed Central

Bacterial endotoxins have strong affinity for metallic biomaterials because of surface energy effects. Conventional depyrogenation methods may not eradicate endotoxins and may compromise biological properties and functionality of metallic instruments and implants. We evaluated the solubilization and removal of E. coli endotoxin from smooth and porous titanium (Ti) surfaces and stainless steel lumens using compressed CO2-based mixtures having water and/or surfactant Ls-54. The CO2/water/Ls-54 ternary mixture in the liquid CO2 region (25 °C and 27.6 MPa) with strong mixing removed endotoxin below detection levels. This suggests that the ternary mixture penetrates and dissolves endotoxins from all the tested substrates. The successful removal of endotoxins from metallic biomaterials with compressed CO2 is a promising cleaning technology for biomaterials and reusable medical devices.

Tarafa, Pedro J.; Williams, Eve; Panvelker, Samir; Zhang, Jian; Matthews, Michael A.



Synergistic Hepatotoxicity from Coexposure to Bacterial Endotoxin and the Pyrrolizidine Alkaloid Monocrotaline  

Microsoft Academic Search

Individuals are commonly exposed to bacterial endotoxin (lipopolysaccharide [LPS]) through gram-negative bacterial infection and from its translocation from the gastrointestinal lumen into the circulation. Inasmuch as noninjurious doses of LPS augment the hepatotoxicity of certain xenobiotic agents, exposure to small amounts of LPS may be an important determinant of susceptibility to chemical intoxication. Monocrotaline (MCT) is a pyrrolizidine alkaloid phytotoxin

Steven B. Yee; Shawn Kinser; Dwayne A. Hill; C. Charles Barton; Jon A. Hotchkiss; Jack R. Harkema; Patricia E. Ganey; Robert A. Roth



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



Anatomic patterns of FOS immunostaining in rat brain following systemic endotoxin administration  

Microsoft Academic Search

To identify brain neurons that participate in the acute phase response, rat brains were examined immunocytochemically for Fos protein following the intravenous administration of bacterial endotoxin (lipopolysaccharide, LIPS). Two to three hours after the injection of LPS, 150 ?g\\/kg body weight, to adult male Long-Evans rats, a consistent anatomic pattern of Fos immunostained cell nuclei is seen. In the brain

Stephen M. Sagar; Kristen J. Price; Norman W. Kasting; Frank R. Sharp



Generation of slow-reacting substance (leukotrienes) by endotoxin and lipid A from human polymorphonuclear granulocytes.  

PubMed Central

Leukotrienes were released from human polymorphonuclear granulocytes on incubation with endotoxins and lipid A. The analysis was performed by their smooth muscle contracting properties, reversed phase high-pressure liquid chromatography and radioimmunoassay for leukotrienes C4 and D4. The active component of the lipopolysaccharides seems to be the lipid A portion.

Bremm, K D; Konig, W; Spur, B; Crea, A; Galanos, C



Etanercept treatment in the endotoxin-induced uveitis of rats.  


This study was conducted to investigate therapeutic value of a soluble tumor necrosis factor-alpha (TNF-alpha) receptor, etanercept, in a rat model of endotoxin-induced uveitis (EIU). Forty-two inbred male Lewis rats were divided into seven equal groups. 200 microg of Escherichia coli 055:B55 lipopolysaccharide (LPS) was injected in one hind footpad of the Groups 2, 3, 4, 5, 6, and 7 rats. Group 5, 6, and 7 rats also received subcutaneous etanercept 24 hr prior to LPS injection at a dose of 0.4 mg kg(-1). Group 1 rats were used as controls. Eight, 24, and 48 hr after treatment clinical uveitis scores (miosis, iris hyperemia, and hypopyon) were assessed by a masked observer and the rats were euthanized. Neutrophil leukocytes, CD8+, CD4+, and CD45RO+ cells in the anterior uveal tissue were counted either after hematoxylin-eosin or monoclonal antibody staining. TNF-alpha levels were also measured in the aqueous humor samples by an ELISA method. Etanercept treatment significantly improved clinical uveitis scores at all examination points compared to the LPS injected animals. The improvement was almost complete expect for the miosis score, since no significant difference was detected between the controls and LPS + Etanercept treated animals at all examination points. Cell counts were also at significantly lower levels in LPS + Etanercept treated animals at all examination points, except for CD8+ and CD45RO+ cell counts at 24 hr examination point. There was no significant difference between the controls and LPS + Etanercept treated animals at all examination points as with CD4+ and CD45RO+ cell counts at 48 hr. Our data showed that etanercept had a definite effect on the treatment of EIU. Further studies should clarify its efficacy on clinical uveitis conditions. PMID:15336498

Avunduk, Mustafa Cihat; Avunduk, Avni Murat; Oztekin, Esma; Baltaci, Abdülkerim Kasim; Ozyazgan, Yilmaz; Mogolkoc, Rasim



Characterization of a lipopolysaccharide mediated neutrophilic hepatitis model in Sprague Dawley rats  

Microsoft Academic Search

Several studies have investigated the role of neutrophils during endotoxin-mediated liver injury, yet the precise mechanism for endotoxin-mediated hepatic neutrophil transmigration is unknown. The primary objective of this study was to establish a reliable lipopolysaccharide (LPS)-mediated necro-hepatitis model to investigate the mecha- nisms of hepatic neutrophil infiltration following LPS administration. Male Sprague Dawley rats were administered a single (5 or

Robert Rose; Atrayee Banerjee; Shashi K. Ramaiah



Saliva IgM and IgA are a sensitive indicator of the humoral immune response to Escherichia coli O157 lipopolysaccharide in children with enteropathic hemolytic uremic syndrome.  


Saliva antibodies to Escherichia coli O157 were investigated as markers of the immune response in children with enteropathic hemolytic uremic syndrome (HUS). Paired serum and saliva samples were collected from 22 children with HUS during acute disease and convalescence and were tested for E. coli O157 lipopolysaccharide (LPS)-specific IgM and IgA antibodies by ELISA. Serum and saliva samples from 44 age-matched controls were used to establish the cut-off values. Elevated levels of IgM and/or IgA antibodies to O157 LPS were detected in saliva of 13/13 HUS patients with Shiga toxin-producing E. coli (STEC) O157 in stool culture and from 4 of 5 HUS patients in whom STEC were not detected. These results closely mirrored the results obtained with paired serum samples. In contrast, saliva and serum samples from four children with STEC isolates belonging to O-groups O26, O145 (n = 2), and O165 lacked detectable O157 LPS-specific antibodies. The specificity of the ELISA was confirmed by western blotting. In STEC O157 culture-confirmed cases, the sensitivity of the ELISA was 92% for saliva IgM and IgA, based on the first available sample, and 100% and 92%, respectively, when subsequent samples were included. The specificity was 98% for IgM and 100% for IgA. Children with E. coli O157 HUS demonstrate a brisk, easily detectable immune response as reflected by the presence of specific antibodies in their saliva. Saliva-based immunoassays offer a reliable, noninvasive method for the diagnosis of E. coli O157 infection in patients with enteropathic HUS. PMID:12149511

Ludwig, Kerstin; Grabhorn, Enke; Bitzan, Martin; Bobrowski, Christoph; Kemper, Markus J; Sobottka, Ingo; Laufs, Rainer; Karch, Helge; Müller-Wiefel, Dirk E



Removal of endotoxins from plasmid DNA: analysis of aggregative interaction of mobile divalent metal cations with endotoxins and plasmid DNA.  


Endotoxin lipopolysaccharide removal from plasmid DNA-based vaccine remains a very challenging task for bioprocess engineers. This paper examined the potential use and advantages of divalent cation (Zn(2+), Ca(2+), Mg(2+)) induced aggregation as a plasmid DNA purification method for lipopolysaccharide removal. Analysis of zeta potential, hydrodynamic size, percentage of aggregation; UV-Vis spectroscopy and electron microscopy were performed to determine the optimal cation for preferential aggregation of lipopolysaccharide over plasmid DNA. The results from the hydrodynamic size analysis showed that the addition of Zn(2+) resulted in the maximum theoretical number of lipopolysaccharide molecules per aggregate particle. Dynamic light scattering analysis showed that plasmid DNA aggregates formed a larger maximum hydrodynamic size when it was treated with Ca(2+) than the other two cations. The K(m) value for lipopolysaccharide-Zn(2+) was substantially low (0.28 M) and considerably large (>2 M) for plasmid DNA-Zn(2+). Scatchard plots for plasmid DNA cations showed positive slopes indicating that there was a minimum concentration of plasmid DNA or cations before a significant aggregation occurred. This work concluded that Zn(2+) had the most preferential aggregative interaction with lipopolysaccharide compared to Mg(2+) and Ca(2+). PMID:23001922

Ongkudon, Clarence M; Hodges, Emma; Murphy, Kathleen; Danquah, Michael K



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.

Lundin, Jessica I.; Checkoway, Harvey



Biosensor of endotoxin and sepsis  

NASA Astrophysics Data System (ADS)

To investigate the relation between biosensor of endotoxin and endotoxin of plasma in sepsis. Method: biosensor of endotoxin was designed with technology of quartz crystal microbalance bioaffinity sensor ligand of endotoxin were immobilized by protein A conjugate. When a sample soliton of plasma containing endotoxin 0.01, 0.03, 0.06, 0.1, 0.5, 1.0Eu, treated with perchloric acid and injected into slot of quartz crystal surface respectively, the ligand was released from the surface of quartz crystal to form a more stable complex with endotoxin in solution. The endotoxin concentration corresponded to the weight change on the crystal surface, and caused change of frequency that occurred when desorbed. The result was biosensor of endotoxin might detect endotoxin of plasma in sepsis, measurements range between 0.05Eu and 0.5Eu in the stop flow mode, measurement range between 0.1Eu and 1Eu in the flow mode. The sensor of endotoxin could detect the endotoxin of plasm rapidly, and use for detection sepsis in clinically.

Shao, Yang; Wang, Xiang; Wu, Xi; Gao, Wei; He, Qing-hua; Cai, Shaoxi



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.



Comparison of the immune response to sheep erythrocytes, tetanus toxoid and endotoxin in different strains of mice  

Microsoft Academic Search

The primary immune response in 7 inbred and 2 outbred mouse strains to SRBC, tetanus toxin and ‘E.coliendotoxin is compared. Significant variations are found in the different strains concerning their antibody response to these antigens. The differences in antibody production reached with SRBC (direct and indirect PFC) and tetanus toxin are on a quantitative level, those with endotoxin also

J. F. Borel



Antimicrobial Action and Cell Agglutination by the Eosinophil Cationic Protein Are Modulated by the Cell Wall Lipopolysaccharide Structure  

PubMed Central

Antimicrobial proteins and peptides (AMPs) are essential effectors of innate immunity, acting as a first line of defense against bacterial infections. Many AMPs exhibit high affinity for cell wall structures such as lipopolysaccharide (LPS), a potent endotoxin able to induce sepsis. Hence, understanding how AMPs can interact with and neutralize LPS endotoxin is of special relevance for human health. Eosinophil cationic protein (ECP) is an eosinophil secreted protein with high activity against both Gram-negative and Gram-positive bacteria. ECP has a remarkable affinity for LPS and a distinctive agglutinating activity. By using a battery of LPS-truncated E. coli mutant strains, we demonstrate that the polysaccharide moiety of LPS is essential for ECP-mediated bacterial agglutination, thereby modulating its antimicrobial action. The mechanism of action of ECP at the bacterial surface is drastically affected by the LPS structure and in particular by its polysaccharide moiety. We have also analyzed an N-terminal fragment that retains the whole protein activity and displays similar cell agglutination behavior. Conversely, a fragment with further minimization of the antimicrobial domain, though retaining the antimicrobial capacity, significantly loses its agglutinating activity, exhibiting a different mechanism of action which is not dependent on the LPS composition. The results highlight the correlation between the protein's antimicrobial activity and its ability to interact with the LPS outer layer and promote bacterial agglutination.

Pulido, David; Moussaoui, Mohammed; Andreu, David; Nogues, M. Victoria



Examining Associations of Circulating Endotoxin with Nutritional Status, Inflammation and Mortality in Hemodialysis Patients  

PubMed Central

Objective Lipopolysaccharide or endotoxin constitutes most part of the outer portion of the cell wall in the gram negative bacteria. Sub-clinical endotoxemia could contribute to increased inflammation and mortality in hemodialysis patients. Endotoxin level and clinical effect are determined by its soluble receptor sCD14 and high density lipoprotein. We examine the hypothesis that endotoxin level correlates with mortality. Methods In this cohort study, endotoxin levels were measured in 306 long-term hemodialysis patients who were then followed for up to 42 months. Soluble CD14 and cytokines levels were also measured. Results The mean (±SD) endotoxin level was 2.31±3.10 EU/ml (min: 0.26 EU/ml, max: 22.94 EU/ml, inter-quartile range: 1.33EU/ml, median: 1.27EU/ml). Endotoxin correlated with C-reactive protein (r = 0.11, p<0.04). On multivariate logistic regression analysis, high body mass index (BMI) and low HDL cholesterol levels were associated with higher endotoxinemia (endotoxin below or above of median). In multivariable Cox regression analysis adjusted for case-mix and nutritional/inflammatory confounders, endotoxin levels in the 3rd quartile vs. 1st quartile was associated with a trend towards increased hazard ratio (HR) for death (HR 1.83, 95% confidence interval: 0.93–3.6, p=0.08). Conclusions In this hemodialysis cohort, we found associations between endotoxinemia and CRP, body composition and HDL. A moderately high endotoxin levels tended to correlate with increased mortality than the highest circulating endotoxin level. Additional studies are required to asses the effect of endotoxemia on mortality in dialysis population.

Feroze, Usama; Kalantar-Zadeh, Kamyar; Sterling, Kevin A; Molnar, Miklos Z.; Noori, Nazanin; Benner, Debbie; Shah, Vhalab; Dwivedi, Rama; Becker, Kenneth; Kovesdy, Csaba P; Raj, Dominic S



Dietary oil composition differentially modulates intestinal endotoxin transport and postprandial endotoxemia  

PubMed Central

Background Intestinal derived endotoxin and the subsequent endotoxemia can be considered major predisposing factors for diseases such as atherosclerosis, sepsis, obesity and diabetes. Dietary fat has been shown to increase postprandial endotoxemia. Therefore, the aim of this study was to assess the effects of different dietary oils on intestinal endotoxin transport and postprandial endotoxemia using swine as a model. We hypothesized that oils rich in saturated fatty acids (SFA) would augment, while oils rich in n-3 polyunsaturated fatty acids (PUFA) would attenuate intestinal endotoxin transport and circulating concentrations. Methods Postprandial endotoxemia was measured in twenty four pigs following a porridge meal made with either water (Control), fish oil (FO), vegetable oil (VO) or coconut oil (CO). Blood was collected at 0, 1, 2, 3 and 5?hours postprandial and measured for endotoxin. Furthermore, ex vivo ileum endotoxin transport was assessed using modified Ussing chambers and intestines were treated with either no oil or 12.5% (v/v) VO, FO, cod liver oil (CLO), CO or olive oil (OO). Ex vivo mucosal to serosal endotoxin transport permeability (Papp) was then measured by the addition of fluorescent labeled-lipopolysaccharide. Results Postprandial serum endotoxin concentrations were increased after a meal rich in saturated fatty acids and decreased with higher n-3 PUFA intake. Compared to the no oil control, fish oil and CLO which are rich in n-3 fatty acids reduced ex vivo endotoxin Papp by 50% (P?endotoxin Papp. Conclusion Overall, these results indicate that saturated and n-3 PUFA differentially regulate intestinal epithelial endotoxin transport. This may be associated with fatty acid regulation of intestinal membrane lipid raft mediated permeability.



Genetic analysis of the O-specific lipopolysaccharide biosynthesis region (rfb) of Escherichia coli K-12 W3110: identification of genes that confer group 6 specificity to Shigella flexneri serotypes Y and 4a.  

PubMed Central

We recently reported a novel genetic locus located in the sbcB-his region of the chromosomal map of Escherichia coli K-12 which directs the expression of group 6-positive phenotype in Shigella flexneri lipopolysaccharide, presumably due to the transfer of O-acetyl groups onto rhamnose residues of the S. flexneri O-specific polysaccharide (Z. Yao, H. Liu, and M. A. Valvano, J. Bacteriol. 174:7500-7508, 1992). In this study, we identified the genetic region encoding group 6 specificity as part of the rfb gene cluster of E. coli K-12 strain W3110 and established the DNA sequence of most of this cluster. The rfbBDACX block of genes, located in the upstream region of the rfb cluster, was found to be strongly conserved in comparison with the corresponding region in Shigella dysenteriae type 1 and Salmonella enterica. Six other genes, four of which were shown to be essential for the expression of group 6 reactivity in S. flexneri serotypes Y and 4a, were identified downstream of rfbX. One of the remaining two genes showed similarities with rfc (O-antigen polymerase) of S. enterica serovar typhimurium, whereas the other, located in the downstream end of the cluster next to gnd (gluconate-6-phosphate dehydrogenase), had an IS5 insertion. Recently, it has been reported that the IS5 insertion mutation (rfb-50) can be complemented, resulting in the formation of O16-specific polysaccharide by E. coli K-12 (D. Liu and P. R. Reeves, Microbiology 140:49-57, 1994). We present immunochemical evidence suggesting that S. flexneri rfb genes also complement the rfb-50 mutation; in the presence of rfb genes of E. coli K-12, S. flexneri isolates express O16-specific polysaccharide which is also acetylated in its rhamnose residues, thereby eliciting group 6 specificity. Images

Yao, Z; Valvano, M A



Salmonella lipopolysaccharide (LPS) mediated neurodegeneration in hippocampal slice cultures  

Microsoft Academic Search

Neuroinflammation has been suggested to play an integral role in the pathophysiology of various neurodegenerative diseases.\\u000a Bacterial lipopolysaccharide (LPS) endotoxins are general activators of immune-cells, including microglial cells, which induce\\u000a expression of pro-inflammatory factors. The aim of this study was to characterize neurodegenerative effects of exposure to\\u000a LPS, derived from Salmonella abortus equi bacteria, in an in vitro brain slice

Sara Johansson; Svante Bohman; Ann-Cathrin Radesäter; Caroline Öberg; Johan Luthman



Lipopolysaccharide enhances the cytotoxicity of 2-chloroethyl ethyl sulfide  

Microsoft Academic Search

BACKGROUND: The bacterial endotoxin, lipopolysaccharide (LPS), is a well-characterized inflammatory factor found in the cell wall of Gram-negative bacteria. In this investigation, we studied the cytotoxic interaction between 2-chloroethyl ethyl sulfide (CEES or ClCH2CH2SCH2CH3) and LPS using murine RAW264.7 macrophages. CEES is a sulfur vesicating agent and is an analog of 2,2'-dichlorodiethyl sulfide (sulfur mustard). LPS is a ubiquitous natural

William L Stone; Min Qui; Milton Smith



Involvement of nitric oxide in lipopolysaccharide induced anorexia  

Microsoft Academic Search

Treatment with the bacterial endotoxin lipopolysaccharide (LPS) is a commonly used model to induce disease-related anorexia. Following LPS treatment inducible nitric oxide synthase (iNOS) is expressed in the hypothalamic arcuate nucleus (ARC), where nitric oxide (NO) inhibits orexigenic neurons. Intracellular STAT signaling is triggered by inflammatory stimuli and has been linked to the transcriptional regulation of iNOS. We evaluated whether

Thomas Riediger; Caroline Cordani; Catarina Soares Potes; Thomas A. Lutz



Involvement of waaY, waaQ, and waaP in the modification of Escherichia coli lipopolysaccharide and their role in the formation of a stable outer membrane.  


The waaY, waaQ, and waaP genes are located in the central operon of the waa (formerly rfa) locus on the chromosome of Escherichia coli. This locus contains genes whose products are involved in the assembly of the core region of the lipopolysaccharide molecule. In the R1 core prototype strain, E. coli F470, there are nine genes in this operon, and all but waaY, waaQ, and waaP have been assigned function. In this study, the waaY, waaQ, and waaP genes were independently mutated by insertion of a non-polar antibiotic resistance cassette, and the structures of the resulting mutant core oligosaccharides were determined by chemical analyses and phosphorus-nuclear magnetic resonance spectroscopy. All three of these mutations were shown to affect the modification of the heptose region of the core, a region whose structure is critical to outer membrane stability. Mutation of waaY resulted in a core oligosaccharide devoid of phosphate on HepII. Mutation of waaQ resulted in loss of the branch HepIII residue on HepII and impeded the activity of WaaY. Mutation of waaP resulted in loss of phosphoryl substituents on HepI and obviated WaaQ and WaaY activity. Only mutation of waaP resulted in hypersensitivity to novobiocin and sodium dodecyl sulfate, a characteristic of deep-rough mutations. PMID:9756860

Yethon, J A; Heinrichs, D E; Monteiro, M A; Perry, M B; Whitfield, C



Pseudomonas aeruginosa B-band lipopolysaccharide genes wbpA and wbpI and their Escherichia coli homologues wecC and wecB are not functionally interchangeable.  


The O antigen unit of Pseudomonas aeruginosa serotype O5 is a complex trisaccharide containing 2-acetamido-3-acetiminido-2, 3-dideoxy-beta-D-mannuronic acid, 2-acetimido-3-acetimido-2, 3-dideoxy-beta-D-mannuronic acid, and 2-acetimido-2, 6-deoxy-beta-D-galactosamine. Specific knockout mutations in the putative UDP-D-N-acetylglucosamine (UDP-D-GlcNAc) epimerase gene, wbpI, or the putative UDP-D-N-acetylmannosamine dehydrogenase gene, wbpA, resulted in strains that no longer produced B-band lipopolysaccharide, confirming the essential roles of these genes in B-band O antigen synthesis. Despite approximately 50% similarity of wbpI and wbpA to the Escherichia coli genes wecB (rffE) and wecC (rffD) involved in enterobacterial common antigen synthesis, cross-complementation experiments were not successful. These results imply that the P. aeruginosa UDP-D-GlcNAc precursor may be di-N-acetylated prior to further modification, preventing the E. coli enzymes from recognizing it as a substrate. PMID:10930727

Burrows, L L; Pigeon, K E; Lam, J S



Molecular mechanisms and pathological consequences of endotoxin tolerance and priming.  


Lipopolysaccharide (LPS), a component of Gram-negative bacteria, is a potent inflammatory stimulant, with high doses due to disseminated bacterial infection resulting in systemic inflammatory response syndrome and death. Lower doses can induce a state of tolerance to subsequent toxic doses of LPS, but extremely low doses have an opposite effect, priming the immune system for an even more violent response to subsequent challenge. A substantial body of research exists on the phenomenon of endotoxin tolerance, which appears to be a state of generalized dampening of inflammatory pathways. Comparatively little is known about the mechanisms or indeed the phenomenon of priming, particularly regarding the shift from a priming to a tolerizing response. Our aim is to review recent findings in the field of the inflammatory response to endotoxin, with a focus on highlighting the gaps in current understanding and attempting to reconcile the competing tolerance and priming phenomena. PMID:22143158

Morris, Matthew; Li, Liwu



Two-component nature of bacteriophage T4 receptor activity in Escherichia coli K-12.  

PubMed Central

Escherichia coli bacteriophage T4 uses the lipopolysaccharide of the outer cell envelope membrane as a receptor. Lipopolysaccharide from E. coli K-12 required a major outer membrane protein, polypeptide Ib, for phage inactivation.

Henning, U; Jann, K



In vivo and in vitro studies of bacterial endotoxin-membrane interactions and the effects of membrane-active agents.  

PubMed Central

The characteristics of 51Cr-labelled E. coli endotoxin binding to human erythrocyte membranes in vitro have been investigated. A saturable component of binding was apparent at low endotoxin concentrations (less than 50 micrograms ml-1) relevant to its in vivo actions, while at higher concentrations binding was non-saturable and increased in linear fashion. Experiments examining the ability of unlabelled endotoxin to antagonize the binding of labelled toxin provided further evidence for these specific and non-specific modes of endotoxin-membrane interaction. Membrane-active agents previously shown to reduce endotoxin toxicity in vivo decreased endotoxin binding to erythrocyte membranes in vitro, with propranolol and pranolium being the most effective in this regard. Tissue distribution studies following administration of radiolabelled endotoxin to guinea-pigs showed a positive correlation between the accumulation of 51Cr-endotoxin in lung and elevations in plasma acid phosphatase activity, a measure of in vivo endotoxin toxicity. The in vivo accumulation of 51Cr-endotoxin in guinea-pig lung was reduced by prior treatment with (+)-propranolol or pranolium, paralleling the results of the in vitro binding studies. Our results suggest that membrane-active agents such as (+)-propranolol may be useful adjuncts to antimicrobial drugs in the therapy of gram-negative endotoxaemia.

Garnett, M. E.; Godin, D. V.; Tuchek, J. M.



Zymosan-induced resistance to endotoxin and hemorrhagic shock.  


Improved surgical techniques and judicial use of available antibiotics have reduced the number of postoperative complications over the past decade. However, septic and hemorrhagic shock occur all too frequently, and each carries with it an appreciable morbidity and mortality. Endotoxins and hemorrhage are both known to suppress the phagocytic activity of the reticuloendothelial system (RES). On the other hand, zymosan, a yeast (Saccharomyces cerevisiae) cell wall preparation administered intravenously, results in temporary RES hyperplasia and increased phagocytic activity. Dogs were pretreated with zymosan to determine the degree of RES stimulation and protection against endotoxin and hemorrhagic shock attainable. Twenty-five dogs received intravenous zymosan (10 mg/kg) on days 1, 2, and 3. Another 24 dogs served as controls. On day four, one-half the animals in each group received E coli endotoxin (1.5 mg/kg) intravenously. The other animals underwent two hours of hemorrhagic shock at a mean blood pressure of 40 mm Hg. Seventy-two hour survival was as follows: Endotoxin treated, 66.7% (8/12); endotoxin control, 27% (3/11); hemorrhagic treated, 53.3% (8/15); and hemorrhagic control, 28.6% (4/14). Hemodynamic, metabolic, and lysosomal enzyme parameters were evaluated. No zymosan toxicity was observed. These findings suggest that an RES stimulant such as zymosan could be incorporated as preoperative adjunctive therapy to induce resistance to these shock syndromes in the elective surgical patient. PMID:262077

Joyce, L D; Smith, J M; Mauer, H G; Ameli, M; Lillehei, R C



Endotoxin removal by magnetic separation-based blood purification.  


This work describes a magnetic separation-based approach using polymyxin B-functionalized metal alloy nanomagnets for the rapid elimination of endotoxins from human blood in vitro and functional assays to evaluate the biological relevance of the blood purification process. Playing a central role in gram-negative sepsis, bacteria-derived endotoxins are attractive therapeutic targets. However, both direct endotoxin detection in and removal from protein-rich fluids remains challenging. We present the synthesis and functionalization of ultra-magnetic cobalt/iron alloy nanoparticles and a magnetic separation-based approach using polymyxin B-functionalized nanomagnets to remove endotoxin from human blood in vitro. Conventional chromogenic Limulus Amebocyte Lysate assays confirm decreased endotoxin activity in purified compared to untreated samples. Functional assays assessing key steps in host defense against bacteria show an attenuated inflammatory mediator expression from human primary endothelial cells in response to purified blood samples compared to untreated blood and less chemotactic activity. Exposing Escherichia coli-positive blood samples to polymyxin B-functionalized nanomagnets even impairs the ability of gram-negative bacteria to form colony forming units, thus making magnetic separation based blood purification a promising new approach for future sepsis treatment. PMID:23225582

Herrmann, Inge K; Urner, Martin; Graf, Samuel; Schumacher, Christoph M; Roth-Z'graggen, Birgit; Hasler, Melanie; Stark, Wendelin J; Beck-Schimmer, Beatrice



Potential use of a liposome-encapsulated mixture of lipopolysaccharide core types (R1, R2, R3 and R4) of Escherichia coli in controlling colisepticaemia in chickens.  


Infections caused by Escherichia coli have an economically significant impact on the poultry industry and a non-serotype-specific vaccine appears to be the most logical method of controlling them. The core oligosaccharide-lipid A region of bacterial lipopolysaccharide (LPS) is well conserved and highly immunogenic but toxic. This study determined the possible use of a liposome-encapsulated mixture of rough LPSs of core types R1, R2, R3 and R4 in controlling infections caused by E. coli in chickens. The liposome which encapsulated the LPS consisted of egg phosphatidylcholine, bovine brain phosphatidylserine and cholesterol. As determined by Limulus amoebocyte lysate assay, incorporation of LPS into the liposome reduced the endotoxicity of LPS to 0.7 % of its initial value. When tested on a chicken macrophage cell line (HD11), liposome-incorporated LPS produced a significantly lower amount of nitric oxide (<5 microM) than that produced by free LPS (22 microM). Transcription of the genes for interleukin-1beta and inducible nitric oxide synthase was lower in cells treated with liposome-incorporated LPS than in cells treated with free LPS. When chickens were immunized with 0.2 microg, 1 microg and 5 microg liposome-encapsulated mixture of LPS core types, the antibody response increased with increasing dose. When challenged with the virulent E. coli O78 strain, the birds which received 1 microg liposome-encapsulated LPS and 5 microg LPS had significantly lower lesions scores (P <0.05) and high body weight when compared with the birds in the control group as well as with the birds immunized with a suboptimal dose (0.2 microg) of liposome-encapsulated LPS. PMID:19797465

Dissanayake, D R Anuruddhika; Wijewardana, Thula G; Gunawardena, Gnana A; Poxton, Ian R



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



Detection of endotoxin-like interleukin-1-inducing activity during in vitro dialysis  

Microsoft Academic Search

Detection of endotoxin-like interleukin-1-inducing activity during in vitro dialysis. In order to study the integrity of dialysis membranes to pyrogens, the dialysate side of a closed loop hemodialysis (HD) circuit was challenged with E. coli microfiltrate containing 500 ng\\/ml endotoxin. Three solutions, a) tissue culture medium\\/saline, b) 5% human serum albumin, and c) 10% fresh human plasma, were circulated in

Gerhard Lonnemann; Marion Bingel; Juergen Floege; Karl M Koch; Charles A Dinarello



Effect of radio-detoxified endotoxin on the liver microsomal drug metabolizing enzyme system in rats  

SciTech Connect

E. coli endotoxin (LPS) depresses the hepatic microsomal mono-oxygenase activity. Radio-detoxified LPS (TOLERIN: /sup 60/Co irradiated endotoxin preparation) decreases this biotransforming activity to a smaller extent. Phenobarbital, an inducer of this mono-oxygenase system, failed to induce in LPS-treated animals. In radio-detoxified LPS-treated rats, phenobarbital induced the mono-oxygenase and almost fully restored the biotransformation.

Bertok, L.; Szeberenyi, S.



Effect of vasopressors on organ blood flow during endotoxin shock in pigs  

Microsoft Academic Search

A volume-resuscitated porcine endotoxin shock model was used to evaluate the effect on organ blood flow of increasing systemic arterial blood pressure with vasopressors. Administration of 0.05-0.2 mg\\/kg of Escherichia coli endotoxin (E) reduced mean arterial blood pressure (MAP) to 50 mmHg, decreased systemic vascular resistance to 50% of control, and did not change cardiac output or heart rate. Blood

M. J. Breslow; C. F. Miller; S. D. Parker; A. T. Walman; R. J. Traystman



Sexually dimorphic secretion of cortisol but not catecholamines in response to an endotoxin challenge in beef cattle  

Technology Transfer Automated Retrieval System (TEKTRAN)

This study was designed to determine the effect of endotoxin (lipopolysaccharide; LPS) challenge on secretion of the adrenal stress-related hormones cortisol, epinephrine, and norepinephrine in bull and heifer calves. Brahman calves (n = 12; 269 ± 11.7 kg) were randomly selected from the fall 2007 c...


Comparison of the immunostimulatory and proinflammatory activities of candidate Gram-positive endotoxins, lipoteichoic acid, peptidoglycan, and lipopeptides, in murine and human cells  

Microsoft Academic Search

The role of lipopolysaccharide (LPS) in the pathogenesis of Gram-negative septic shock is well established. The corresponding proinflammatory and immunostimulatory molecule(s) on the Gram-positive bacteria is less well understood, and its identification and characterization would be a key prerequisite in designing specific sequestrants of the Gram-positive endotoxin(s). We report in this paper the comparison of NF-?B-, cytokine- and chemokine-inducing activities

Matthew R. Kimbrell; Hemamali Warshakoon; Jens R. Cromer; Subbalakshmi Malladi; Jennifer D. Hood; Rajalakshmi Balakrishna; Tandace A. Scholdberg; Sunil A. David



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



Endotoxin induction of an inhibitor of plasminogen activator in bovine pulmonary artery endothelial cells  

SciTech Connect

The effects of bacterial lipopolysaccharide (endotoxin) on the fibrinolytic activity of bovine pulmonary artery endothelial cells were examined. Endotoxin suppressed the net fibrinolytic activity of cell extracts and conditioned media in a dose-dependent manner. The effects of endotoxin required at least 6 h for expression. Cell extracts and conditioned media contained a 44-kDa urokinase-like plasminogen activator. Media also contained multiple plasminogen activators with molecular masses of 65-75 and 80-100 kDa. Plasminogen activators in extracts and media were unchanged by treatment of cells with endotoxin. Diisopropyl fluorophosphate (DFP)-abolished fibrinolytic activity of extracts and conditioned media. DFP-treated samples from endotoxin-treated but not untreated cells inhibited urokinase and tissue plasminogen activator, but not plasmin. Inhibitory activity was lost by incubation at pH 3 or heating to 56/sup 0/C for 10 min. These treatments did not affect inhibitory activity of fetal bovine serum. Incubation of /sup 125/I-urokinase with DFP-treated medium from endotoxin-treated cells produced an inactive complex with an apparent molecular mass of 80-85 kDa.

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PubMed Central

Unanesthetized immature albino rabbits exposed to 2 hours of severe but reversible hemorrhagic shock induced with aseptic precautions by multiple cardiac bleedings exhibited no increase in susceptibility to single intravenous injections of 200 µg./kg. E. coli endotoxin administered 4 hours post retransfusion, a quantity of endotoxin that was found to be the largest dose uniformly non-lethal to normal rabbits. Paired and randomly selected rabbits treated identically except for the additional procedure of a femoral arterial cutdown and ligation (without aseptic precautions) exhibited increases in susceptibility to the same endotoxin of several hundredfold. This effect could not be attributed to the femoral cutdown and arterial ligation alone since such trauma when coupled with sham cardiac bleedings failed to increase susceptibility to 200 µg./kg. of endotoxin. These data appear valid since sham cardiac bleedings produced no detectable impairment of myocardial contractility, while 2 hours of hemorrhagic shock at 50 mm. Hg with the Lamson reservoir technique caused an increase in endotoxin susceptibility comparable to that seen when cardiac bleedings were combined with a non-sterile femoral arterial cutdown and ligation. The mechanisms increasing the susceptibility to E. coli endotoxin were investigated. It was found that (a) rabbit femoral skeletal muscle is normally contaminated with clostridia, (b) the use of aseptic femoral wounding precautions exerted some suggestive protective influence, (c) the use of aseptic wounding precautions combined with immediate topical sulfanilamide and wound closure exerted a significant protective influence, and (d) prophylactic polyvalent gas gangrene antitoxin protected in a manner not demonstrable when diphtheria antitoxin was employed as a control. These observations suggest that clostridial wound infection is one mechanism whereby a femoral arterial cutdown lowers endotoxin resistance of the rabbit following hemorrhagic shock. It is, however, not the only mechanism since the ligation of a femoral artery during hemorrhagic shock led to edema following retransfusion equivalent to a mean of approximately 30 per cent of the original circulating plasma volume. The intensification of shock caused by this transudation presumably intensified reticulo-endothelial injury, and thus further lowered the resistance of the rabbit to an intravenous injection of endotoxin 4 hours following retransfusion.

Greisman, Sheldon E.



Grape seed procyanidin extract reduces the endotoxic effects induced by lipopolysaccharide in rats.  


Acute inflammation is a response to injury, infection, tissue damage, or shock. Bacterial lipopolysaccharide (LPS) is an endotoxin implicated in triggering sepsis and septic shock, and LPS promotes the inflammatory response, resulting in the secretion of proinflammatory and anti-inflammatory cytokines such as the interleukins (IL-6, IL-1?, and IL-10) and tumor necrosis factor-? by the immune cells. Furthermore, nitric oxide and reactive oxygen species levels increase rapidly, which is partially due to the activation of inducible nitric oxide synthase in several tissues in response to inflammatory stimuli. Previous studies have shown that procyanidins, polyphenols present in foods such as apples, grapes, cocoa, and berries, have several beneficial properties against inflammation and oxidative stress using several in vitro and in vivo models. In this study, the anti-inflammatory and antioxidant effects of two physiological doses and two pharmaceutical doses of grape seed procyanidin extract (GSPE) were analyzed using a rat model of septic shock by the intraperitoneal injection of LPS derived from Escherichia coli. The high nutritional (75mg/kg/day) and the high pharmacological doses (200mg/kg/day) of GSPE showed anti-inflammatory effects by decreasing the proinflammatory marker NOx in the plasma, red blood cells, spleen, and liver. Moreover, the high pharmacological dose also downregulated the genes Il-6 and iNos; and the high nutritional dose decreased the glutathione ratio (GSSG/total glutathione), further illustrating the antioxidant capability of GSPE. In conclusion, several doses of GSPE can alleviate acute inflammation triggered by LPS in rats at the systemic and local levels when administered for as few as 15 days before the injection of endotoxin. PMID:23439188

Pallarčs, Victor; Fernández-Iglesias, Anabel; Cedó, Lídia; Castell-Auví, Anna; Pinent, Montserrat; Ardévol, Anna; Salvadó, Maria Josepa; Garcia-Vallvé, Santiago; Blay, Mayte



Endotoxin suppresses surfactant synthesis in cultured rat lung cells  

SciTech Connect

Pulmonary complications secondary to postburn sepsis are a major cause of death in burned patients. Using an in vitro organotypic culture system, we examined the effect of E. coli endotoxin (LPS) on lung cell surfactant synthesis. Our results showed that E. coli endotoxin (1.0, 2.5, 10 micrograms LPS/ml) was capable of suppressing the incorporation of /sup 3/H-choline into de novo synthesized surfactant, lamellar bodies (LB), and common myelin figures (CMF) at 50%, 68%, and 64%, respectively. In a similar study, we were able to show that LPS also inhibited /sup 3/H-palmitate incorporation by cultured lung cells. LPS-induced suppression of surfactant synthesis was reversed by hydrocortisone. Our results suggest that LPS may play a significant role in reducing surfactant synthesis by rat lung cells, and thus contribute to the pathogenesis of sepsis-related respiratory distress syndrome (RDS) in burn injury.

Li, J.J.; Sanders, R.L.; McAdam, K.P.; Gelfand, J.A.; Burke, J.F.



Expression of genes kdsA and kdsB involved in 3-deoxy-D-manno-octulosonic acid metabolism and biosynthesis of enterobacterial lipopolysaccharide is growth phase regulated primarily at the transcriptional level in Escherichia coli K-12.  


We have cloned and sequenced a cluster of six open reading frames containing gene kdsA from Escherichia coli K-12. The gene encodes 3-deoxy-D-manno-octulosonate 8-phosphate synthetase (KDO-8-phosphate synthetase), which catalyzes formation of 3-deoxy-D-manno-octulosonic acid (KDO), an essential component of enterobacterial lipopolysaccharide. We have also identified two other genes, hemA and prfA, at the beginning of the cluster. Deletion analysis shows that kdsA, the terminal gene of this putative operon, is transcribed from its own promoter located within the cluster rather than from two promoters preceding this group of six open reading frames. Northern (RNA) blot analysis as well as lacZ operon fusion experiments reveal that the expression of gene kdsA occurs maximally in the early log phase and falls to a low level in the late log and stationary phases. Hence, this gene is subjected to growth phase-dependent regulation at the transcriptional level. Similarly, we show that expression of gene kdsB, which codes for the CTP:CMP-3-deoxy-D-manno-octulosonate cytidyltransferase (CMP-KDO-synthetase), is also growth regulated. This enzyme catalyzes the activation of KDO via formation of CMP-KDO, which is necessary for the incorporation of KDO into lipid A. We have identified the promoter of gene kdsB, whose expression is growth regulated in the same way as that of kdsA. Despite the fact that transcription of genes kdsA and kdsB is shut off as cells enter stationary phase, KDO-8-phosphate synthetase as well as CMP-KDO-synthetase activities are still present at various levels during stationary-phase growth of an E. coli K-12 culture. PMID:7543480

Strohmaier, H; Remler, P; Renner, W; Högenauer, G



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

Microsoft Academic Search

Mild acid hydrolysis of the lipopolysaccharide produced by Escherichiacoli O118:H16 standard strain (NRCC 6613) afforded an O-polysaccharide (O-PS) composed of d-galactose, 2-acetamidoylamino-2,6-dideoxy-l-galactose , 2-acetamido-2-deoxy-d-glucose, ribitol, and phosphate (1:1:1:1:1). From DOC-PAGE, sugar and methylation analyses, one- and two-dimensional NMR spectroscopy, capillary electrophoresis-mass spectrometry, hydrolysis, and sequential Smith-type periodate oxidation studies, the O-PS was determined to be an unbranched linear polymer having

Leann L. MacLean; Yanhong Liu; Evgeny Vinogradov; Malcolm B. Perry


Endotoxin Activity of Moraxella osloensis against the Grey Garden Slug, Deroceras reticulatum  

PubMed Central

Moraxella osloensis is a gram-negative bacterium associated with Phasmarhabditis hermaphrodita, a slug-parasitic nematode that has prospects for biological control of mollusk pests, especially the grey garden slug, Deroceras reticulatum. This bacterium-feeding nematode acts as a vector that transports M. osloensis into the shell cavity of the slug, and the bacterium is the killing agent in the nematode-bacterium complex. We discovered that M. osloensis produces an endotoxin(s), which is tolerant to heat and protease treatments and kills the slug after injection into the shell cavity. Washed or broken cells treated with penicillin and streptomycin from 3-day M. osloensis cultures were more pathogenic than similar cells from 2-day M. osloensis cultures. However, heat and protease treatments and 2 days of storage at 22°C increased the endotoxin activity of the young broken cells but not the endotoxin activity of the young washed cells treated with the antibiotics. This suggests that there may be a proteinaceous substance(s) that is structurally associated with the endotoxin(s) and masks its toxicity in the young bacterial cells. Moreover, 2 days of storage of the young washed bacterial cells at 22°C enhanced their endotoxin activity if they were not treated with the antibiotics. Furthermore, purified lipopolysaccharide (LPS) from the 3-day M. osloensis cultures was toxic to slugs, with an estimated 50% lethal dose of 48 ?g per slug, thus demonstrating that the LPS of M. osloensis is an endotoxin that is active against D. reticulatum. This appears to be the first report of a biological toxin that is active against mollusks.

Tan, Li; Grewal, Parwinder S.



The Chemical Composition of Endotoxin Isolated from Intestinal Strain of Desulfovibrio desulfuricans  

PubMed Central

Desulfovibrio desulfuricans anaerobes are constituents of human alimentary tract microflora. There are suggestions that they take part in the pathogenesis of periodontitis and some gastrointestinal inflammatory disorders, such as ulcerative colitis or Crohn's disease. Endotoxin is one of Gram-negative bacteria cellular components that influence these microorganisms pathogenicity. Endotoxin is a lipid-polisaccharide heteropolymer consisting of three elements: lipid A, core oligosaccharide, and O-specific polysaccharide, also called antigen-O. The biological activity of lipopolysaccharide (LPS) is determined by its structure. In this study, we show that rhamnose, fucose, mannose, glucose, galactose, heptose, and 2-keto-3-deoxyoctulosonic acid (Kdo) are constituents of D. desulfuricans endotoxin oligosaccharide core and O-antigen. Lipid A of these bacteria LPS is composed of glucosamine disaccharide substituted by 3-acyloxyacyl residues: ester-bound 3-(dodecanoyloxy)tetradecanoic, 3-(hexadecanoyloxy)tetradecanoic acid, and amide-bound 3-(tetradecanoyloxy)tetradecanoic acid.

Lodowska, Jolanta; Wolny, Daniel; Jaworska-Kik, Marzena; Kurkiewicz, Slawomir; Dzierzewicz, Zofia; Weglarz, Ludmila



Activity of lipopolysaccharide-binding protein-bactericidal/permeability-increasing protein fusion peptide in an experimental model of Pseudomonas sepsis.  

PubMed Central

A chimeric protein consisting of the N-terminal domain of lipopolysaccharide-binding protein and the C-terminal domain of bactericidal/permeability-increasing protein demonstrated a dose-dependent survival benefit (P = 0.001) and reduced endotoxin levels (P < 0.01) in neutropenic rats with Pseudomonas aeruginosa sepsis. This lipopolysaccharide-binding protein-bactericidal/ permeability-increasing peptide has favorable pharmacokinetics and antiendotoxin properties which may be of value for human sepsis.

Opal, S M; Palardy, J E; Jhung, J W; Donsky, C; Romulo, R L; Parejo, N; Marra, M N



Biophysical Mechanisms of Endotoxin Neutralization by Cationic Amphiphilic Peptides  

PubMed Central

Bacterial endotoxins (lipopolysaccharides (LPS)) are strong elicitors of the human immune system by interacting with serum and membrane proteins such as lipopolysaccharide-binding protein (LBP) and CD14 with high specificity. At LPS concentrations as low as 0.3 ng/ml, such interactions may lead to severe pathophysiological effects, including sepsis and septic shock. One approach to inhibit an uncontrolled inflammatory reaction is the use of appropriate polycationic and amphiphilic antimicrobial peptides, here called synthetic anti-LPS peptides (SALPs). We designed various SALP structures and investigated their ability to inhibit LPS-induced cytokine secretion in vitro, their protective effect in a mouse model of sepsis, and their cytotoxicity in physiological human cells. Using a variety of biophysical techniques, we investigated selected SALPs with considerable differences in their biological responses to characterize and understand the mechanism of LPS inactivation by SALPs. Our investigations show that neutralization of LPS by peptides is associated with a fluidization of the LPS acyl chains, a strong exothermic Coulomb interaction between the two compounds, and a drastic change of the LPS aggregate type from cubic into multilamellar, with an increase in the aggregate sizes, inhibiting the binding of LBP and other mammalian proteins to the endotoxin. At the same time, peptide binding to phospholipids of human origin (e.g., phosphatidylcholine) does not cause essential structural changes, such as changes in membrane fluidity and bilayer structure. The absence of cytotoxicity is explained by the high specificity of the interaction of the peptides with LPS.

Kaconis, Yani; Kowalski, Ina; Howe, Jorg; Brauser, Annemarie; Richter, Walter; Razquin-Olazaran, Iosu; Inigo-Pestana, Melania; Garidel, Patrick; Rossle, Manfred; Martinez de Tejada, Guillermo; Gutsmann, Thomas; Brandenburg, Klaus



Pulmonary Endotoxin Tolerance Protects against Cockroach Allergen-Induced Asthma-Like Inflammation in a Mouse Model  

PubMed Central

Background Compounds which activate the innate immune system, such as lipopolysaccharide, are significant components of ambient air, and extremely difficult to remove from the environment. It is currently unclear how prior inhalation of endotoxin affects allergen sensitization. We examined whether lung-specific endotoxin tolerance induction prior to sensitization can modulate the response to allergen. Methods Endotoxin tolerance was induced by repeated intratracheal exposure to endotoxin. All mice were then sensitized and challenged by direct intratracheal instillation of cockroach allergen. Results After allergen sensitization and challenge, endotoxin tolerant mice had significantly decreased airways hyperresponsiveness to methacholine challenge, which was confirmed by invasive lung function tests. Decreased goblet cell hyperplasia and mucus production were also found by histological assessment. Tolerant mice were protected from airway eosinophilia through the mechanism of reduced CCL11 and CCL24. Interestingly, endotoxin tolerant mice had only a modest reduction in cockroach-specific IgE; however, total IgE was significantly reduced. Conclusions These data show that induction of endotoxin tolerance prior to sensitization protects against the hallmark features of asthma-like inflammation, and that transient modulation of innate immunity can have long-lasting effects on adaptive responses.

Natarajan, Sudha; Kim, Jiyoun; Bouchard, Jacqueline; Cruikshank, William; Remick, Daniel G.



Endotoxin Potentiation of Trichothecene-Induced Lymphocyte Apoptosis Is Mediated by Up-Regulation of Glucocorticoids  

Microsoft Academic Search

Exposure to bacterial endotoxin (lipopolysaccharide, LPS) is quite common and may increase human susceptibility to chemical-induced tissue injury. The purpose of this study was to identify mechanisms by which LPS potentiates lymphoid tissue depletion in B6C3F1 mice exposed to the common food-borne trichothecene mycotoxin, vomitoxin (VT). As demonstrated by DNA fragmentation and flow cytometric analysis, apoptosis in thymus, Peyer's patches,

Zahidul Islam; Yu Seok Moon; Hui-Ren Zhou; Louis E. King; Pamela J. Fraker; James J. Pestka



Endotoxin-induced Ileal Mucosal Injury and Nitric Oxide Dysregulation Are Temporally Dissociated  

Microsoft Academic Search

Despite recent investigations, the mechanisms responsible for in- testinal epithelial injury during endotoxemia remain unclear. The present study tests the hypothesis that epithelial necrosis and\\/or apoptosis correlate with nitric oxide (NO) dysregulation in a non- ischemic model of sepsis-induced ileal injury. To test this hypothe- sis, a well-established in situ , autoperfused, feline ileal preparation was employed. After endotoxin (lipopolysaccharide




Persistence and in vivo effects of Yersinia enterocolitica 0:3 endotoxin in rats  

Microsoft Academic Search

In vivo effects of Yersinia enterocolitica 0:3 lipopolysaccharide (prepared from bacteria grown at 25°C and 37°C) were investigated after intraperitoneal (i.p.) and intraarticular (i.a.) injection in rats during 30 days of examination. The persistence of endotoxin in the peritoneal and the synovial cavities was demonstrated by the immunofluorescence technique. Peritoneal and synovial exudative cell infiltration, as well as changes in

Nadya Markova; Tatyana Radoucheva; Vesselin Kussovski; Krassimira Dilova; Iva Paskaleva; Klavdia Veleva



Flavonoids protect mice from two types of lethal shock induced by endotoxin  

Microsoft Academic Search

The protective effect of flavonoids on two types of lethal endotoxic shock was studied. A lethal endotoxic shock was induced by administration of lipopolysaccharide (LPS) into D-galactosamine (D-GalN)-sensitized mice and another one was done by administration of a high dose of LPS into normal mice. Pretreatment with a series of flavonoids protected mice from two types of endotoxin lethality. Flavonoid

K Takahashi; A Morikawa; Y Kato; T Sugiyama; N Koide; M. M Mu; T Yoshida; T Yokochi



Distribution of 3Hydroxy Fatty Acids in Tissues after Intraperitoneal Injection of Endotoxin  

Microsoft Academic Search

Background: 3-Hydroxy fatty acids (3-OH FAs) with 10- to 18-carbon chain lengths are constituents of the endo- toxin (lipopolysaccharide (LPS)) of gram-negative bac- teria. We investigated whether these FAs may be used as chemical markers in measuring endotoxin concentra- tions in mammalian tissue samples. Methods: We used gas-liquid chromatography-tandem mass spectrometry to measure 3-OH FAs in serum and tissues (heart,

Bogumiřa Szponar; Leonard Krasnik; Tomasz Hryniewiecki; Andrzej Gamian; Lennart Larsson


DOK3 negatively regulates LPS responses and endotoxin tolerance.  


Innate immune activation via Toll-like receptors (TLRs), although critical for host defense against infection, must be regulated to prevent sustained cell activation that can lead to cell death. Cells repeatedly stimulated with lipopolysaccharide (LPS) develop endotoxin tolerance making the cells hypo-responsive to additional TLR stimulation. We show here that DOK3 is a negative regulator of TLR signaling by limiting LPS-induced ERK activation and cytokine responses in macrophages. LPS induces ubiquitin-mediated degradation of DOK3 leading to SOS1 degradation and inhibition of ERK activation. DOK3 mice are hypersensitive to sublethal doses of LPS and have altered cytokine responses in vivo. During endotoxin tolerance, DOK3 expression remains stable, and it negatively regulates the expression of SHIP1, IRAK-M, SOCS1, and SOS1. As such, DOK3-deficient macrophages are more sensitive to LPS-induced tolerance becoming tolerant at lower levels of LPS than wild type cells. Taken together, the absence of DOK3 increases LPS signaling, contributing to LPS-induced tolerance. Thus, DOK3 plays a role in TLR signaling during both naďve and endotoxin-induced tolerant conditions. PMID:22761938

Peng, Qisheng; O'Loughlin, Jason L; Humphrey, Mary Beth



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

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.

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



Interactions of lipopolysaccharide with lipid membranes, raft models - a solid state NMR study.  


Lipopolysaccharide (LPS) is a major component of the external leaflet of bacterial outer membranes, key pro-inflammatory factor and an important mediator of host-pathogen interactions. In host cells it activates the complement along with a pro-inflammatory response via a TLR4-mediated signalling cascade and shows preference for cholesterol-containing membranes. Here, we use solid state (13)C and (31)P MAS NMR to investigate the interactions of LPS from three bacterial species, Brucella melitensis, Klebsiella pneumoniae and Escherichia coli, with mixed lipid membranes, raft models. All endotoxin types are found to be pyrophosphorylated and Klebsiellar LPS is phosphonylated, as well. Carbon-13 MAS NMR indicates an increase in lipid order in the presence of LPS. Longitudinal (31)P relaxation, providing a direct probe of LPS molecular and segmental mobility, reveals a significant reduction in (31)P T1 times and lower molecular mobility in the presence of ternary lipid mixtures. Along with the ordering effect on membrane lipid, this suggests a preferential partitioning of LPS into ordered bilayer sphingomyelin/cholesterol-rich domains. We hypothesise that this is an important evolutionary drive for the selection of GPI-anchored raft-associated LPS-binding proteins as a first line of response to membrane-associated LPS. PMID:23567915

Ciesielski, Filip; Griffin, David C; Rittig, Michael; Moriyón, Ignacio; Bonev, Boyan B



High in vitro immune reactivity to Escherichia coli in neuromyelitis optica patients is correlated with both neurological disabilities and elevated plasma lipopolysaccharide levels.  


The pathogenesis of neuromyelitis optica (NMO) is influenced by a combination of genetic and environmental factors, including infectious agents. Several infectious diseases can both trigger or exacerbate autoimmunity. The objective of the present work was to evaluate the in vitro immune responsiveness to Escherichia coli (EC), Staphylococcus aureus (SA) and Candida albicans (CA) in remittent-recurrent NMO patients, and correlate it with the level of neurological disability. Our results revealed that the extent of lymphoproliferation and cytokine profile in response to SA- and CA-stimulated PBMC cultures was similar between NMO patients and healthy individuals. Nevertheless, a higher in vitro CD4(+) T cell proliferation associated with elevated IL-1?, IL-6 and IL-17 release was observed in NMO-derived EC-stimulated cell cultures. Additionally, in these last cultures, the IL-10 production was significantly lower as compared with control group. The in vitro EC-induced levels of IL-6 and IL-17 were positively related with neurological disabilities. This higher tendency to produce Th17-related cytokines was proportional to the production of IL-23 and IL-6 by LPS-activated monocytes. Interestingly, elevated LPS levels were quantified in the plasma of NMO patients. The results suggest that a higher Th17-responsiveness to E. coli could be involved in the NMO pathogenesis. PMID:23777933

Barros, Priscila O; Linhares, Ulisses C; Teixeira, Bruna; Kasahara, Taissa M; Ferreira, Thais B; Alvarenga, Regina; Hygino, Joana; Silva-Filho, Renato G; Bittencourt, Vera Carolina B; Andrade, Regis M; Andrade, Arnaldo F; Bento, Cleonice A M



The Stimulation by Endotoxin of the Nonspecific Resistance of Mice to Bacterial Infections  

PubMed Central

The nonspecific resistance of mice to challenge was enhanced following the administration of an E. coli O55 B5 endotoxin. Although the route of administration of the endotoxin and the challenge organism were varied, the nonspecific resistance of the animal was enhanced in all the experiments. The efficiency of this resistance was highest when the inducing substance and the challenge dose of bacteria were administered intraperitoneally. Poly I: C and double stranded RNA were also studied but were much less effective than endotoxin in stimulating a resistance to infection. Stimulation of the fixed macrophages could not explain fully the enhanced resistance, since the clearance rates of colloidal carbon and radioactively labelled bacteria from the blood were not significantly enhanced after the administration of endotoxin. Furthermore, splenectomized animals, and animals injected with agents which interfere with the RES activity, trypan blue and corticosteroids, still developed a degree of nonspecific resistance to infection.

Hill, A. W.; Hibbitt, K. G.; Shears, A.



Endotoxin deactivation by transient acidification.  


Recombinant proteins are an important tool for research and therapeutic applications. Therapeutic proteins have been delivered to several cell types and tissues and might be used to improve the outcome of the cell transplantation. Recombinant proteins are propagated in bacteria, which will contaminate them with the lypopolysacharide endotoxin found in the outer bacterial membrane. Endotoxin could interfere with in vitro biological assays and is the major pathological factor, which must be removed or inactivated before in vivo administration. Here we describe a one-step protocol in which the endotoxin activity on recombinant proteins is remarkably reduced by transient exposure to acidic conditions. Maximum endotoxin deactivation occurs at acidic pH below their respective isoelectric point (pI). This method does not require additional protein purification or separation of the protein from the endotoxin fraction. The endotoxin level was measured both in vitro and in vivo. For in vitro assessment we have utilized Limulus Amebocyte Lysate method for in vivo the pyrogenic test. We have tested the above-mentioned method with five different recombinant proteins, including a monoclonal antibody clone 5c8 against CD154 produced by hybridomas. More than 99% of endotoxin was deactivated in all of the proteins; the recovery of the protein after deactivation varied between maximum 72.9% and minimum 46.8%. The anti-CD154 clone 5c8 activity remained unchanged as verified by the measurement of binding capability to activated lymphocytes. Furthermore, the effectiveness of this method was not significantly altered by urea, commonly used in protein purification. This procedure provides a simple and cost-efficient way to reduce the endotoxin activity in antibodies and recombinant proteins. PMID:20412635

Ribeiro, Melina M; Xu, Xiumin; Klein, Dagmar; Kenyon, Norma S; Ricordi, Camillo; Felipe, Maria Sueli S; Pastori, Ricardo L



Prevention of experimental endotoxin shock by a monocyte activator.  

PubMed Central

In patients with polytrauma or major surgery, severe bacterial infections leading to septic shock and multiorgan failure are still a major cause of death. Prevention of septic shock in patients at risk would be an alternative to treatment of patients with overt septic shock. We therefore conducted a trial with the monocyte activator muramyl tripeptide phosphatidylethanolamine (MTP-PE) in an experimental pig model. Liposome encapsulated MTP-PE (50 micrograms/kg of body weight) or liposomes alone were given intravenously at 72 or 24 h before endotoxemia was induced by lipopolysaccharide (LPS), simultaneously with the induction of endotoxin shock, or 1 h thereafter. Pretreatment with MTP-PE at 72 and 24 h before endotoxemia was induced resulted in a reduction of endotoxin shock-induced mortality from 81.8% (9 of 11 animals) in the control group to 8.3% (1 of 12 animals) of the MTP-PE-pretreated animals (P < 0.001). The administration of MTP-PE 24 h before the induction of endotoxin shock was more effective (P < 0.01) than administration of MTP-PE 72 h before endotoxemia was induced (P = 0.05). The pretreated animals did not develop fever or cardiovascular complications, and pulmonary function was significantly improved. Furthermore, the alpha-form of the soluble CD14 LPS receptor in pig serum showed a marked decrease in LPS-treated animals, and this decrease was reduced by MTP-PE pretreatment at 24 h before endotoxemia was induced. When MTP-PE was given simultaneously with the induction of septic shock or 1 h thereafter, it did not influence either mortality or morbidity. In conclusion, pretreatment of pigs with MTP-PE improves several parameters of endotoxin shock and it reduces mortality. Patients with high risk of developing septic complications might benefit from a pretreatment with this monocyte-activating substance.

Passlick, B; Labeta, M O; Izbicki, J R; Ostertag, P; Loffler, T; Siebeck, M; Pichlmeier, U; Schweiberer, L; Ziegler-Heitbrock, H W



Temperature Dependence of the Binding of Endotoxins to the Polycationic Peptides Polymyxin B and Its Nonapeptide  

PubMed Central

The interaction between endotoxins—free lipid A and various lipopolysaccharide (LPS) chemotypes with different sugar chain lengths—and the polycationic peptides polymyxin B and polymyxin nonapeptide has been investigated by isothermal titration calorimetry between 20 and 50°C. The results show a strong dependence of the titration curves on the phase state of the endotoxins. In the gel phase (<30°C for LPS and <45°C for lipid A), an endothermic reaction is observed, for which the driving force is an entropically driven endotoxin-polymyxin interaction, due to disruption of the ordered water structure and cation assembly in the lipid A backbone and adjacent molecules. In the liquid crystalline phase (>35°C for LPS and >47°C for lipid A) an exothermic reaction takes place, which is mainly due to the strong electrostatic interaction of the polymyxins with the negative charges of the endotoxins, i.e., the entropic change ?S is much lower than in the gel phase. For endotoxins with short sugar chains (lipid A, LPS Re, LPS Rc) the stoichiometry of the polymyxin binding corresponds to pure charge neutralization; for the compounds with longer sugar chains (LPS Ra, LPS S-form) this is no longer valid. This can be related to the lower susceptibility of the corresponding bacterial strains to antibiotics.

Brandenburg, Klaus; David, Alexander; Howe, Jorg; Koch, Michel H. J.; Andra, Jorg; Garidel, Patrick



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



Alterations in human red blood cell membrane properties induced by the lipopolysaccharide from Proteus mirabilis S1959  

Microsoft Academic Search

The effect of lipopolysaccharide (LPS, endotoxin), isolated from Proteus mirabilis S1959 strain, on red blood cell (RBC) membranes in whole cells as well as on isolated membranes was studied. Lipid membrane fluidity, conformational state of membrane proteins and the osmotic fragility of RBCs were examined using electron paramagnetic resonance spectroscopy and spectrophotometric method. Lipid membrane fluidity was determined using three

Krzysztof Gwozdzinski; Anna Pieniazek; Beata Sudak; Wieslaw Kaca



Protective effect of vitamin E, ?-carotene and N-acetylcysteine from the brain oxidative stress induced in rats by lipopolysaccharide  

Microsoft Academic Search

The major goal of this study was to examine the ability of several antioxidants namely, vitamin E, ?-carotene and N-acetylcysteine, to protect the brain from oxidative stress induced by lipopolysaccharide (LPS, endotoxin). LPS, a component of the bacterial wall of gram-negative bacteria, has been recognized as one of the most potent bacterial products in the induction of host inflammatory responses

Adel A Kheir-Eldin; Tarek K Motawi; Mohamed Z Gad; Hanan M Abd-ElGawad



Enhanced Resistance of Gastric Mucosa to Damaging Agents in the Rat Stomach Adapted to Helicobacter pylori Lipopolysaccharide  

Microsoft Academic Search

Background and Aim: Lipopolysaccharide (LPS) has been proposed to act as one of numerous virulence factors in the Helicobacter pylori (HP)-infected stomach. However, little is known as to whether the gastric mucosa can withstand the repeated LPS insult, and how the possible adaptation to this endotoxin influences the damage induced by strong irritants. We determined the effect of a single

Tomasz Brzozowski; Peter C. Konturek; Anthony P. Moran; Slawomir Kwiecien; Robert Pajdo; Stanislaw J. Konturek; Danuta Drozdowicz; Agata Ptak; Wieslaw Pawlik; Eckhart G. Hahn



Aldose reductase inhibition prevents lipopolysaccharide-induced glucose uptake and glucose transporter 3 expression in RAW264.7 macrophages  

Microsoft Academic Search

Macrophages which play a central role in the injury, infection and sepsis, use glucose as their primary source of metabolic energy. Increased glucose uptake in inflammatory cells is well known to be one of the responsible processes that cause inflammatory response and cytotoxicity. We have shown recently that the inhibition of aldose reductase (AR) prevents bacterial endotoxin, lipopolysaccharide (LPS)-induced cytotoxicity

Aramati B. M. Reddy; Satish K. Srivastava; Kota V. Ramana



Effect of Lipopolysaccharides of Various Structures on the Adhesion of and Generation of Active Oxygen Species by Human Neutrophils  

Microsoft Academic Search

Damaging effects of lipopolysaccharides (LPSs, endotoxins) are generally believed to play the key role in sepsis and septic shock associated with pathogenesis of gram-negative infections. LPSs are very strong activators of the human immune system and nonspecific resistance [1]. The molecule of LPS consists of three main structural units: a branched polysaccharide moiety (an O-specific antigen), a central oligosaccharide (core),

M. G. Vinokurov; I. R. Prokhorenko; M. M. Yurinskaya; S. V. Prokhorenko; S. V. Grachev



Short Term Effects of Nonspecific Resistance Induced by Endotoxin on the Distribution and Viability of Bacteria Injected into Mice  

PubMed Central

Staphylococcus aureus and Salmonella dublin were injected intraperitoneally into normal white mice and mice previously made tolerant to E. coli 055 B5 endotoxin. One hour after injection, the animals were killed and blood samples taken; the liver and spleen were removed and homogenized. In all cases, the tissues of endotoxin treated animals contained lower numbers of viable bacteria. When the proteins of the injected bacteria were labelled with tritiated leucine, the radioactivity of the liver, spleen and blood indicated that the numbers of bacteria present in these tissues were unaffected by the endotoxin.

Hill, A. W.; Hibbitt, K. G.; Shears, A. L.



Toxicologic interactions between ozone and bacterial endotoxin  

SciTech Connect

The effects of acute exposure of mice to bacterial lipopolysaccharide (LPS), the endotoxin of gram negative microorganisms, and ozone (O3) have been investigated. Intraperitoneal (ip) administration of 5 mg/kg LPS to CD-1 mice followed by exposure to 15 ppm O3 for 1.5 hr produced synergistic effects as measured by pulmonary edemagenesis and lethality assays. In contrast, ip administration of 0.1-1.6 mg/kg LPS to CD-1 mice over 5 consecutive days, a dose regimen resulting in LPS tolerance, protected against a lethal challenge of 20 ppm O3 for 3 hr. A statistically significant increase in catalase and glutathione peroxidase activity was measured in homogenates of lungs obtained from CD-1 mice receiving a tolerance-inducing regimen of LPS. These results demonstrate that two, distinct toxicologic interactions can occur between O3 and bacterial LPS. Synergism between these agents could explain, in part, the increased susceptibility of O3-exposed animals to respiratory infection with gram negative microorganisms. Protection resulting from LPS-induced increases in pulmonary antioxidant activity provides additional evidence that O3 and, possibly, LPS mediate their toxicity through oxidative mechanisms.

Peavy, D.L.; Fairchild, E.J. II




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,...


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.

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



Recombinant Interleukin-1 Alpha and Recombinant Tumor Necrosis Factor Alpha Synergize In vivo to Induce Early Endotoxin Tolerance and Associated Hematopoietic Changes,  

National Technical Information Service (NTIS)

Endotoxin, the lipopolysaccharide (LPS) derived from gram-negative bacteria, invokes a wide range of responses in susceptible hosts. It is known that virtually all responses to LPS are mediated by the action of macrophage-derived cytokines (such as interl...

E. N. Kaufman M. D. Tate R. Neta S. N. Vogel



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



Impairment of Endotoxin-Induced Macrophage Inflammatory Protein 2 Gene Expression in Alveolar Macrophages in Streptozotocin-Induced Diabetes in Mice  

Microsoft Academic Search

To elucidate the mechanism of the high incidence of lower respiratory tract infections in patients with diabetes mellitus, we investigated the kinetics of production of macrophage inflammatory protein 2 (MIP-2), an important mediator of lung neutrophil recruitment, using mice with streptozotocin-induced diabetes. Intratracheal challenge with 1 mg of lipopolysaccharide (LPS), an endotoxin, per kg of body weight resulted in a




Superoxide anion generation by in situ perfused rat liver: effect of in vivo endotoxin.  


A simple method is described to monitor the superoxide dismutase (SOD)-inhibitable production of superoxide anion (O2-.) in the liver. The isolated rat liver was perfused in situ with ferricytochrome c, and the reduction of this substrate during perfusion was determined. Within 30 s after the introduction of the substrate, significant reduction of ferricytochrome c was observed and stabilized at 2-4 min. A marked reduction of the substrate was observed in the livers of rats that received Escherichia coli lipopolysaccharide (LPS, 1 mg/kg) in vivo 3 h before liver perfusion. Ferricytochrome c reduction was inhibited by SOD, but not significantly with allopurinol or deferoxamine mesylate in the livers of LPS-treated rats. Control livers exhibited only a small reduction of the substrate, and this was not significantly inhibited by SOD. After in vivo LPS administration, O2-. production peaked in the liver at 3 h (6.6 nmol/min) and returned toward normal at 6 h (1 nmol/min) after endotoxin. The amount of O2-. generated by the endotoxic livers was dose related. At 3 h post-LPS, neutrophil infiltration and necrotic areas were found in the histological sections of the liver with concomitant elevation of serum aminotransferases, indicating hepatic abnormalities during the early stage of endotoxemia. Phorbol myristate acetate in the perfusion system markedly enhanced O2-. generation in the endotoxic liver. These results show that the perfused rat liver can be used to measure O2-. generation following in vivo stimuli. The data also demonstrate that O2-. release after LPS treatment in vivo is a short and early event and may have an important role in hepatic injury in endotoxemic conditions. PMID:2175553

Bautista, A P; Spitzer, J J



Endogenous vasopressin increases acute endotoxin shock-provoked gastrointestinal mucosal injury in the rat  

Microsoft Academic Search

Administration of a low dose of endotoxin (from Escherichia coli, 3 mgkg?1, i.v.), which does not affect vascular permeability or blood pressure over 1 h, leads to the release of endogenous vasopressin and damage to the mucosal microvasculature. Thus, endogenous vasopressin could be involved in septic shock. In the present study, we investigated the role of endogenous vasopressin in gastrointestinal

Csaba Varga; Imre Pávó; Dominique Lamarque; Zoltán Szepes; József Kiss; Gizella Karácsony; Ferenc A László



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...


Structural features of Salmonella typhimurium lipopolysaccharide required for activation of tissue factor in human mononuclear cells.  

PubMed Central

Activation of mononuclear cell tissue factor was examined utilizing lipopolysaccharides obtained from wild-type and both Rc and Re mutants of Salmonella typhimurium. Wild-type (smooth) lipopolysaccharide, galactose-deficient (Rc) lipopolysaccharide, heptose-deficient (Re) lipopolysaccharide, and lipid A preparations were all active in their ability to generate tissue factor activity in human mononuclear cells grown in tissue culture. Polymyxin B has been reported to prevent some of the lethal effects of endotoxin in vivo, and the drug reportedly binds to the 2-keto-3-deoxyoctulosonate-lipid A region of the lipopolysaccharide molecule. Polymyxin B was effective in inhibiting the tissue factor generating activity of wild-type lipopolysaccharide, Re lipopolysaccharide, and lipid A in a dose-dependent fashion. Treatment of lipid A preparations with mild alkali abolished the ability of these preparations to activate tissue factor in cells. Analogous to many of the other biologic properties of lipopolysaccharide, tissue factor activation in human mononuclear cells appears to depend upon the integrity of the lipid A portion of the molecule.

Rickles, F R; Rick, P D



Effects of Puerariae Radix Extract on Endotoxin Receptors and TNF-? Expression Induced by Gut-Derived Endotoxin in Chronic Alcoholic Liver Injury  

PubMed Central

Kudzu (Pueraria lobata) is one of the earliest medicinal plants used to treat alcohol abuse in traditional Chinese medicine for more than a millennium. However, little is known about its effects on chronic alcoholic liver injury. Therefore, the present study observed the effects of puerariae radix extract (RPE) on chronic alcoholic liver injury as well as Kupffer cells (KCs) activation to release tumor necrosis factor alpha (TNF-?) induced by gut-derived endotoxin in rats and macrophage cell line. RPE was observed to alleviate the pathological changes and lipids deposition in liver tissues as well as the serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and hepatic gamma-glutamyl transpeptidase (GGT) activity. Meanwhile, RPE inhibited KCs activation and subsequent hepatic TNF-? expression and downregulated the protein expression of endotoxin receptors, lipopolysaccharide binding protein (LBP), CD14, Toll-like receptor (TLR) 2, and TLR4 in chronic alcohol intake rats. Furthermore, an in vitro study showed that RPE inhibited the expression of TNF-? and endotoxin receptors, CD14 and TLR4, induced by LPS in RAW264.7 cells. In summary, this study demonstrated that RPE mitigated liver damage and lipid deposition induced by chronic alcohol intake in rats, as well as TNF-? release, protein expression of endotoxin receptors in vivo or in vitro.

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



Physicochemical characterization of the endotoxins from Coxiella burnetii strain Priscilla in relation to their bioactivities  

PubMed Central

Background Coxiella burnetii is the etiological agent of Q fever found worldwide. The microorganism has like other Gram-negative bacteria a lipopolysaccharide (LPS, endotoxin) in its outer membrane, which is important for the pathogenicity of the bacteria. In order to understand the biological activity of LPS, a detailed physico-chemical analysis of LPS is of utmost importace. Results The lipid A moiety of LPS is tetraacylated and has longer (C-16) acyl chains than most other lipid A from enterobacterial strains. The two ester-linked 3-OH fatty acids found in the latter are lacking. The acyl chains of the C. burnetii endotoxins exhibit a broad melting range between 5 and 25°C for LPS and 10 and 40°C for lipid A. The lipid A moiety has a cubic inverted aggregate structure, and the inclination angle of the D-glucosamine disaccharide backbone plane of the lipid A part with respect to the membrane normal is around 40°. Furthermore, the endotoxins readily intercalate into phospholipid liposomes mediated by the lipopolysaccharide-binding protein (LBP). The endotoxin-induced tumor necrosis factor ? (TNF?) production in human mononuclear cells is one order of magnitude lower than that found for endotoxins from enterobacterial strains, whereas the same activity as in the latter compounds is found in the clotting reaction of the Limulus amebocyte lysate assay. Conclusions Despite a considerably different chemical primary structure of the C. burnetii lipid A in comparison with enterobacterial lipid A, the data can be well understood by applying the previously presented conformational concept of endotoxicity, a conical shape of the lipid A moiety of LPS and a sufficiently high inclination of the sugar backbone plane with respect to the membrane plane. Importantly, the role of the acyl chain fluidity in modulating endotoxicity now becomes more evident.

Toman, Rudolf; Garidel, Patrick; Andra, Jorg; Slaba, Katarina; Hussein, Ahmed; Koch, Michel HJ; Brandenburg, Klaus



All-trans retinoic acid and intra-amniotic endotoxin-mediated effects on fetal sheep lung.  


All-trans retinoic acid (RA) is a potent modulator of lung development. Chorioamnionitis, which is frequently associated with preterm birth, causes fetal lung inflammation and improves lung function but also results in alveolar simplification and microvascular injury. Endotoxin-mediated chorioamnionitis reduces RA concentration in the fetal lung to 16% of control values. We hypothesized that administration of RA to the fetus before induction of chorioamnionitis would preserve septation of the distal airspaces. Time-mated ewes with singletons were assigned to receive a fetal intramuscular treatment with 20,000 IU of RA in olive oil (or olive oil only) 3 hr prior to intra-amniotic injection of endotoxin (20 mg, E. coli 055:B5) or saline, at 124-day gestational age and 7 days after the fetal treatment. The right cranial lung lobe was processed for morphometric analysis. RA treatment did not affect chorioamnionitis-induced fetal and systemic inflammation or interleukin-8 concentrations in lung tissue. RA administration alone did not alter lung structure. Relative to control lungs (5 +/- 3 mL/kg), lung volume increased similarly with endotoxin (22 +/- 4 mL/kg) or RA plus endotoxin (20 +/- 3 mL/kg; P < 0.05). Alveolar wall thickness was 4.2 +/- 0.3 mum after endotoxin-induced chorioamnionitis, 6.0 +/- 0.4 mum in controls (P < 0.05 versus endotoxin) and 5.5 +/- 0.2 mum after RA and endotoxin (P < 0.05 versus control, n.s. versus endotoxin). The ratio of airspace versus tissue was 4.6 +/- 0.3 in endotoxin-induced chorioamnionitis, 2.1 +/- 0.3 in controls and 4.1 +/- 0.5 after RA and endotoxin. We conclude that fetal treatment with RA did not prevent inflammation-induced alveolar simplification. PMID:18727105

Kramer, B W; Albertine, K H; Moss, T J M; Nitsos, I; Ladenburger, A; Speer, C P; Newnham, J P; Jobe, A H




PubMed Central

Mice of different strains were protected against the lethal effect of bacterial endotoxin by concurrent injections of cortisone. Either inadequate amounts of cortisone or excessive quantities of endotoxin voided the protection. Analyses of blood sugar, liver glycogen, muscle glycogen, and total body carbohydrate in the skinned eviscerated carcass were carried out on different strains of mice given endotoxin and/or cortisone. Poisoned animals were virtually depleted of all carbohydrate while mice given cortisone alone had concentrations of carbohydrate from three to four times that of normal mice. Mice given a lethal amount of endotoxin and a protective dose of cortisone had two to three times as much carbohydrate as animals injected with the same amount of endotoxin alone but significantly less than that found in normal mice. Dibenzyline failed to alter the lethal effect of endotoxin and to reduce the carbohydrate loss that accompanied endotoxin administration. Endotoxin, at the dosage level employed, lowered the temperature of mice 2°–3°C. during the first hour or two postinjection and the temperature remained essentially unaltered during the next 4 to 5 hours. Loss in body carbohydrate in endotoxin-poisoned mice cannot be explained, therefore, as the result of an elevated metabolic rate accompanying hyperthermia. Endotoxin prevented the conversion of injected glucose into liver glycogen but not into muscle glycogen. Mouse liver mitochondria, in the presence of endotoxin, released from ATP approximately the same amount of inorganic phosphate as that released in the presence of dinitrophenol.

Berry, L. Joe; Smythe, Dorothy S.; Young, Leona G.



Inactivation of Endotoxin by Polymyxin B  

PubMed Central

The limulus gelation assay was utilized to investigate endotoxin inactivation by a number of antibiotics in vitro. Endotoxin activity was sharply reduced by polymyxin B and sodium colistimethate. The effect of the polymyxin was not significantly inhibited by 0.001 M calcium or 90% serum. Crude endotoxins from a variety of aerobic gram-negative bacteria, including several not previously studied, could be inactivated 1 or more logs by as little as 1 ?g of polymyxin B per ml, whereas Bacteroides fragilis endotoxin was poorly detoxified. A 10,000-fold range in the relative susceptibility of different endotoxins to inactivation by polymyxin B was found. The endotoxin most susceptible to polymyxin B was derived from an organism resistant to polymyxin B by disk sensitivity testing, suggesting that the bacteriocidal and endotoxin detoxifying properties of polymyxin need not be directly related.

Cooperstock, Michael S.



CR3 (CD11b/CD18) activation of nasal neutrophils: a measure of upper airway endotoxin exposure.  


Inhaled endotoxin (lipopolysaccharide, LPS) initiates an inflammatory response and leads to the expression of CR3 (CD11b/CD18) receptors on polymorphonuclear leukocytes (PMNs). We determined if PMN activation in nasal lavage fluid (NLF) is a possible biomarker of occupational endotoxin exposure. Seven subjects exposed to endotoxin provided NLF samples that were split into three aliquots (negative control--1 M nicotinamide; sham; positive control--11 etag of exogenous LPS) and PMN activation was measured using a chemiluminometer. Differences in mean PMN activation were apparent, negative control: 548 +/- 15.65 RLU 100 microl(-1); sham: 11469 +/- 2582 RLU 100 microl(-1); positive control: 42026 +/- 16659 RLU 100 microl (n = 7; p <0.05). This technique shows promise as a diagnostic method for measuring upper airway LPS exposure. PMID:19863185

Seth, Romy; Romaschin, Alexander D; Ribeiro, Marcos; Tarlo, Susan M



Endotoxin markers in bronchoalveolar lavage fluid of patients with interstitial lung diseases  

PubMed Central

Background Exposure to inhaled endotoxins (lipopolysaccharides, LPS) of Gram-negative bacteria commonly found in indoor environments and assessed in secondary tobacco smoke, has been associated with airway inflammation and asthma exacerbation. The bronchoalveolar lavage fluid (BALf) from patients with interstitial lung diseases (sarcoidosis, lung fibrosis, smoking-related ILD, eosinophilic disorders) was analyzed for the markers of lipopolysaccharide (LPS, endotoxin). Methods BALf was obtained from patients with diffuse lung diseases: idiopathic pulmonary fibrosis (n = 42), sarcoidosis (n = 22), smoking-related-ILD (n = 11) and eosinophilic disorders (n = 8). Total cell count and differential cell count were performed. In addition, samples were analyzed for 3-hydroxy fatty acids (3-OHFAs) of 10–18 carbon chain lengths, as markers of LPS, by gas chromatography-tandem mass spectrometry. Results The highest LPS concentration was found in patients with eosinophilic disorders and the lowest in patients with sarcoidosis (p< 0.05) followed by the lung fibrosis and the sr-ILD patients. The difference between LPS in BALf with extremely high eosinophil proportion (> 25%) and those with lower proportion was also significant (p = 0.014). A significant correlation was found between LPS and eosinophils, but not between LPS and lymphocytes, neutrophils, or macrophages count. Conclusions A positive relationship of LPS and eosinophilic pulmonary disorders may be linked to a persistent eosinophil activation mediated by Th2 pathway: chronic endotoxin exposure would intensify Th2 pathway resulting in fibrosis and, at the same time, eosinophil stimulation, and hence in eosinophilic pulmonary disorders.



The effect of paeoniflorin against lipopolysaccharide-induced oxidative stress and lipid metabolism  

Microsoft Academic Search

Paeoniflorin (PF), a monoterpene glucoside, is one of the main bioactive components extracted from paeony root. Lipopolysaccharide\\u000a (LPS) is a bacterial endotoxin capable of inducing extensive damage to organs, including the liver, because it stimulates\\u000a increased production of free radicals and boosts lipid peroxidation. LPS induces the synthesis of several inflammatory cytokines\\u000a and chemokines, as well as NO and inflammation

In Deok Kim; Bae Jin Ha



Activation of Interleukin6\\/STAT3 in Rat Cholangiocyte Proliferation Induced by Lipopolysaccharide  

Microsoft Academic Search

Background Cholangiocytes are exposed to endotoxins (lipopolysaccharide, LPS) in a variety of biliary inflammations. It is known that\\u000a LPS enhances the release of interleukin (IL)-6, a potent cholangioycte mitogen. However, the role of LPS in cholangiocyte\\u000a proliferation in vivo is unknown. Aims To investigate whether LPS stimulates cholangiocyte proliferation in vivo via the IL-6\\/STAT3 pathway. Methods Rats were randomized into four groups:

Li-Ping Chen; Ming Cai; Qi-Hao Zhang; Zhou-Li Li; Ye-Yong Qian; Hong-Wei Bai; Xing Wei; Bing-Yi Shi; Jia-Hong Dong



Increased lipopolysaccharide binding protein in cirrhotic patients with marked immune and hemodynamic derangement  

Microsoft Academic Search

Intestinal bacterial overgrowth and translocation, both common in cirrhosis with ascites, may lead to the activation of monocytes and lymphocytes, increased levels of proinflammatory cytokines, and enhanced synthesis of nitric oxide present in cirrhosis. Bacterial endotoxin promotes the synthesis of lipopolysaccharide (LPS)-binding protein (LBP), and forms a LPS-LBP complex that binds to CD14. This study was designed to evaluate LBP

Agust??n Albillos; Antonio de la Hera; Mónica González; Jose-Luis Moya; Jose-Luis Calleja; Jorge Monserrat; Luis Ruiz-del-Arbol; Melchor Alvarez-Mon



Bezafibrate improves bacterial lipopolysaccharide-induced dyslipidemia and anorexia in rats  

Microsoft Academic Search

Bacterial endotoxin\\/lipopolysaccharide (LPS)-induced cachexia is characterized by weight loss, anorexia, and a disturbance in lipid metabolism, namely, hypertriacylglycerolemia. The aim of this study in rats with acute endotoxicity induced by an injection of LPS was to investigate whether bezafibrate, a ligand for peroxisome proliferator–activated receptor ? and a lipoprotein lipase (LPL) activator, improved cachectic conditions, including impaired lipid metabolism. Short-term administration

Nagakatsu Harada; Akiko Kusuyama; Masaki Morishima; Kazuko Okada; Akira Takahashi; Yutaka Nakaya



Structure–activity relationships of lipopolysaccharide sequestration in guanylhydrazone-bearing lipopolyamines  

Microsoft Academic Search

The toxicity of Gram-negative bacterial endotoxin (lipopolysaccharide, LPS) resides in its structurally highly conserved glycolipid component called lipid A. Our major goal has been to develop small-molecules that would sequester LPS by binding to the lipid A moiety, so that it could be useful for the prophylaxis or adjunctive therapy of Gram-negative sepsis. We had previously identified in rapid-throughput screens

Wenyan Wu; Diptesh Sil; Michal L. Szostak; Subbalakshmi S. Malladi; Hemamali J. Warshakoon; Matthew R. Kimbrell; Jens R. Cromer; Sunil A. David



Effects of slow-releasing colistin microspheres on endotoxin-induced sepsis.  


Lipopolysaccharide (LPS) is a major contributing factor to endotoxic shock. Colistin specifically binds to LPS. However, it has the disadvantages that adverse reactions are common and it has a short half-life. To overcome these disadvantages, we prepared slow-releasing colistin microspheres and examined the efficacy of these colistin microspheres in a mouse model of endotoxin-induced sepsis. We prepared the colistin microspheres using poly-lactic-co-glycolic acid. For acute toxicity investigations, mice were overdosed with colistin sulfate or colistin microspheres. The group administered with colistin microspheres was associated with less acute toxicity and fewer nephrotoxic changes on histopathological examination compared to the group administered with colistin sulfate alone. For pharmacokinetic analysis, mice were subcutaneously administered with colistin microspheres or colistin sulfate alone. The plasma concentration of colistin was higher in the colistin microspheres group than in the colistin sulfate group at 12 and 24 h after administration. Moreover, mice were intraperitoneally injected with LPS and then immediately subcutaneously administered with blank microspheres, colistin microspheres or colistin sulfate alone. The levels of endotoxin in the sera and cytokine in the spleens were then measured. A significant reduction in the serum endotoxin level in the colistin microspheres group was observed at 24 h. The reduced endotoxin levels in the sera were correlated with the lower cytokine levels in the spleens of mice treated with colistin microspheres. Our results suggest that the use of colistin microspheres may help to maintain a higher colistin concentration in blood, reduce the levels of endotoxin and cytokines in endotoxin-induced sepsis, and lead to decreased toxicity. PMID:23354935

Nanjo, Yuta; Ishii, Yoshikazu; Kimura, Soichiro; Fukami, Toshiro; Mizoguchi, Masahiro; Suzuki, Toyofumi; Tomono, Kazuo; Akasaka, Yoshikiyo; Ishii, Toshiharu; Takahashi, Kazuhisa; Tateda, Kazuhiro; Yamaguchi, Keizo



Endotoxins stimulate neutrophil adhesion followed by synthesis and release of platelet-activating factor in microparticles.  


Lipopolysaccharides and triacyl-cysteine-modified proteins of Gram-negative and positive organisms are potent endotoxins. Animal models show that the receptor for platelet-activating factor (PAF) is responsible for many of the deleterious effects of endotoxin, where regulated, localized PAF production localizes the inflammatory response. In contrast, biologically active analogs of PAF (PAF-like lipids) are generated by oxidative attack on phospholipids by chemical reactions that are unregulated and unlocalized. The identity and distribution of the PAF receptor ligand in endotoxemia is unknown. We found human polymorphonuclear leukocytes (PMNs) were a significant source of PAF receptor agonists after stimulation by either class of endotoxin. Production of PAF receptor agonists required that the PMN adhere to a surface, and adhesion (and therefore accumulation of PAF-like bioactivity) in response to endotoxic stimulation was delayed for several minutes. PAF-like oxidized phospholipids were found by mass spectroscopy, but biosynthetic PAF accounted for most of the phospholipid agonists arising from endotoxic stimulation. A significant portion of the PAF made by PMNs was secreted, in contrast to its near complete retention by other inflammatory cells. Endotoxic stimulation induced a respiratory burst with the production of superoxide and the formation and shedding of microparticles. Free and microparticle-bound PAF appeared in the media, and blocking microvesiculation with calpeptin blocked PAF release. The released material activated platelets, and platelets co-aggregated with endotoxin-stimulated PMNs. Adherent PMNs therefore behave differently than suspended cells and are a significant source of free PAF after endotoxin exposure. Leukocytes can couple endotoxic challenge to the widespread circulatory and inflammatory effects of endotoxin. PMID:12810708

Watanabe, Junji; Marathe, Gopal K; Neilsen, Paul O; Weyrich, Andrew S; Harrison, Kathleen A; Murphy, Robert C; Zimmerman, Guy A; McIntyre, Thomas M



Interlaboratory evaluation of endotoxin analyses in agricultural dusts--comparison of LAL assay and mass spectrometry.  


Endotoxin exposure is associated with wheeze and asthma morbidity, while early life exposure may reduce risk of allergy and asthma. Unfortunately, it is difficult to compare endotoxin results from different laboratories and environments. We undertook this study to determine if lipopolysaccharide (LPS) extraction efficiency could account for differences among laboratories. We generated and collected aerosols from chicken and swine barns, and corn processing. We randomly allocated side-by-side filter samples to five laboratories for Limulus assay of endotoxin. Lyophilized aliquots of filter extracts were analyzed for 3-hydroxy fatty acids (3-OHFAs) as a marker of LPS using gas chromatography-mass spectrometry. There were significant differences in endotoxin assay and GC-MS (LPS) results between laboratories for all dust types (p < 0.01). Patterns of differences between labs varied by dust type. Relationships between assay and GC/MS results also depended on dust type. The percentages of individual 3-OHFA chain lengths varied across labs (p < 0.0001) suggesting that each lab recovered a different fraction of the LPS available. The presence of large amounts of particle associated LPS and absence of a freezing thawing cycle were associated with lower correlations between LPS and bioactivity, consistent with an absence of Limulus response to cell-bound endotoxin. These data suggest that extraction methods affect endotoxin measurements. The LAL methods may be most suitable when comparing exposures within similar environments; GC-MS offers additional information helpful in optimizing sample treatment and extraction. GC-MS may be of use when comparing across heterogeneous environments and should be considered for inclusion in future studies of human health outcomes. PMID:16307099

Reynolds, Stephen J; Milton, Donald K; Heederik, Dick; Thorne, Peter S; Donham, Kelley J; Croteau, Elizabeth A; Kelly, Kevin M; Douwes, Jeroen; Lewis, Daniel; Whitmer, Mike; Connaughton, Ian; Koch, Sharon; Malmberg, Per; Larsson, Britt-Marie; Deddens, Jim; Saraf, Anita; Larsson, Lennart



Comparative Analysis of Hepatic CD14 Expression between Two Different Endotoxin Shock Model Mice: Relation between Hepatic Injury and CD14 Expression  

PubMed Central

CD14 is a glycoprotein that recognizes gram-negative bacterial lipopolysaccharide (LPS) and exists in both membrane-bound and soluble forms. Infectious and/or inflammatory diseases induce CD14 expression, which may be involved in the pathology of endotoxin shock. We previously found that the expression of CD14 protein differs among the endotoxin shock models used, although the reasons for these differences are unclear. We hypothesized that the differences in CD14 expression might be due to liver injury, because the hepatic tissue produces CD14 protein. We investigated CD14 expression in the plasma and liver in the carrageenan (CAR)-primed and D-galN-primed mouse models of endotoxin shock. Our results showed that severe liver injury was not induced in CAR-primed endotoxin shock model mice. In this CAR-primed model, the higher mRNA and protein expression of CD14 was observed in the liver, especially in the interlobular bile duct in contrast to D-galN-primed-endotoxin shock model mice. Our findings indicated that the molecular mechanism(s) underlying septic shock in CAR-primed and D-galN-primed endotoxin shock models are quite different. Because CD14 expression is correlated with clinical observations, the CAR-primed endotoxin shock model might be useful for studying the functions of CD14 during septic shock in vivo.

Hozumi, Hiroyasu; Tada, Rui; Murakami, Taisuke; Adachi, Yoshiyuki; Ohno, Naohito



Comparative analysis of hepatic CD14 expression between two different endotoxin shock model mice: relation between hepatic injury and CD14 expression.  


CD14 is a glycoprotein that recognizes gram-negative bacterial lipopolysaccharide (LPS) and exists in both membrane-bound and soluble forms. Infectious and/or inflammatory diseases induce CD14 expression, which may be involved in the pathology of endotoxin shock. We previously found that the expression of CD14 protein differs among the endotoxin shock models used, although the reasons for these differences are unclear. We hypothesized that the differences in CD14 expression might be due to liver injury, because the hepatic tissue produces CD14 protein. We investigated CD14 expression in the plasma and liver in the carrageenan (CAR)-primed and D-galN-primed mouse models of endotoxin shock. Our results showed that severe liver injury was not induced in CAR-primed endotoxin shock model mice. In this CAR-primed model, the higher mRNA and protein expression of CD14 was observed in the liver, especially in the interlobular bile duct in contrast to D-galN-primed-endotoxin shock model mice. Our findings indicated that the molecular mechanism(s) underlying septic shock in CAR-primed and D-galN-primed endotoxin shock models are quite different. Because CD14 expression is correlated with clinical observations, the CAR-primed endotoxin shock model might be useful for studying the functions of CD14 during septic shock in vivo. PMID:23308276

Hozumi, Hiroyasu; Tada, Rui; Murakami, Taisuke; Adachi, Yoshiyuki; Ohno, Naohito



NF-?B-mediated degradation of the coactivator RIP140 regulates inflammatory responses and contributes to endotoxin tolerance  

Microsoft Academic Search

Tolerance to endotoxins that is triggered by prior exposure to Toll-like receptor (TLR) ligands provides a mechanism with which to dampen inflammatory cytokines. The receptor-interacting protein RIP140 interacts with the transcription factor NF-?B to regulate the expression of genes encoding proinflammatory cytokines. Here we found lipopolysaccharide stimulation of kinase Syk–mediated tyrosine phosphorylation of RIP140 and interaction of the NF-?B subunit

Ping-Chih Ho; Yao-Chen Tsui; Xudong Feng; David R Greaves; Li-Na Wei



Endotoxin pretreatment protects against the hepatotoxicity of acetaminophen and carbon tetrachloride: role of cytochrome P450 suppression  

Microsoft Academic Search

Bacterial endotoxin (lipopolysaccharide, LPS) is known to potentiate the toxicity of many hepatotoxicants. However, exposure to a sublethal dose of LPS renders animals tolerant to a lethal dose of LPS, and protects against the toxicity of some chemicals. This study was designed to examine the effects of LPS pretreatment on acetaminophen- and carbon tetrachloride (CCl4)-induced liver injury in LPS-sensitive C3H\\/OuJ

Jie Liu; Louis E Sendelbach; Andrew Parkinson; Curtis D Klaassen



Contribution of soluble endotoxin released from Gram-negative bacteria by antibiotics to the pathogenesis of experimental sepsis in mice  

Microsoft Academic Search

The results from our laboratory summarized in this review support the importance of endotoxin release from the Gram-negative microbe as a requirement for the full manifestation of the biological activity of the lipopolysaccharide (LPS) macromolecule. They further suggest that LPS is the most important bacterial component released from Gram-negative microbes treated in vitro with cell-wall active antibiotics in terms of

D. C. Morrison; S. E. Bucklin; M. C. Leeson; M. Norimatsu



Lipopolysaccharide binding protein enhances the responsiveness of alveolar macrophages to bacterial lipopolysaccharide. Implications for cytokine production in normal and injured lungs.  

PubMed Central

A plasma lipopolysaccharide (LPS)-binding protein (LBP) has been shown to regulate the response of rabbit peritoneal macrophages and human blood monocytes to endotoxin (LPS). We investigated whether LBP is present in lung fluids and the effects of LBP on the response of lung macrophages to LPS. Immunoreactive LBP was detectable in the lavage fluids of patients with the adult respiratory distress syndrome by immunoprecipitation followed by Western blotting, and also by specific immunoassay. In rabbits, the LBP appeared to originate outside of the lungs, inasmuch as mRNA transcripts for LBP were identified in total cellular RNA from liver, but not from lung homogenates or alveolar macrophages. Purified LBP enhanced the response of human and rabbit alveolar macrophages to both smooth form LPS (Escherichia coli O111B:4) and rough form LPS (Salmonella minnesota Re595). In the presence of LBP and LPS, the onset of tumor necrosis factor-alpha (TNF alpha) production occurred earlier and at an LPS threshold dose that was as much as 1,000-fold lower for both types of LPS. In rabbit alveolar macrophages treated with LBP and LPS, TNF alpha mRNA appeared earlier, reached higher levels, and had a prolonged half-life as compared with LPS treatment alone. Neither LPS nor LPS and LBP affected pHi or [Cai++] in alveolar macrophages. Specific monoclonal antibodies to CD14, a receptor that binds LPS/LBP complexes, inhibited TNF alpha production by human alveolar macrophages stimulated with LPS alone or with LPS/LBP complexes, indicating the importance of CD14 in mediating the effects of LPS on alveolar macrophages. Thus, immunoreactive LBP accumulates in lung lavage fluids in patients with lung injury and enhances LPS-stimulated TNF alpha gene expression in alveolar macrophages by a pathway that depends on the CD14 receptor. LBP may play an important role in augmenting TNF alpha expression by alveolar macrophages within the lungs. Images

Martin, T R; Mathison, J C; Tobias, P S; Leturcq, D J; Moriarty, A M; Maunder, R J; Ulevitch, R J



Morphometric changes of the lung induced by inhaled bacterial endotoxin.  


Due to the ubiquitous nature of airborne endotoxin, an understanding of pulmonary alterations which follow inhalation of environmentally realistic concentrations of purified bacteria derived lipopolysaccharide (LPS) is important. Using LPS derived from Enterobacter agglomerans, a bacterium found in cotton and cotton mill dust, aqueous aerosols (effective LPS concentration 4 micrograms/m3) were generated and used to expose either normal hamsters (N = 6) or those rendered endotoxin tolerant by pre-ip injection of 0.1 LD50 LPS. Control groups (normal--N = 6; tolerant--N = 6) received saline aerosol only. At 6 hr after 5-hr aerosol exposure, lungs of all animals were fixed, processed for light and transmission electron microscopy, and subject to qualitative and to multitiered morphometric analysis using standard point counting techniques. Qualitative evaluation of TEM micrographs from LPS aerosolized-nontolerant hamsters showed endothelial alteration (focal disruption, subendothelial space formation, and cytoplasmic blebbing) but volume and number of endothelial cells were not changed indicating only slight, focal endothelial damage. Quantitatively, septal capillary blood space in nontolerant, LPS aerosolized hamsters showed increased Vv of PMNs and platelets. These changes were not seen in tolerant induced-LPS aerosolized hamsters. Independent of tolerization treatment, LPS inhalation led to a decrease in fixed lung volume and an increase in numerical density of endothelial pinocytotic vesicles. It is concluded that the inhalation of realistic, environmental levels of bacterial endotoxin may induce significant changes in distal lung and may be important in the pathogenesis of byssinosis and adult respiratory distress syndrome. PMID:4065310

Lantz, R C; Birch, K; Hinton, D E; Burrell, R



Arginase Activity Mediates Retinal Inflammation in Endotoxin-Induced Uveitis  

PubMed Central

Arginase has been reported to reduce nitric oxide bioavailability in cardiovascular disease. However, its specific role in retinopathy has not been studied. In this study, we assessed the role of arginase in a mouse model of endotoxin-induced uveitis induced by lipopolysaccharide (LPS) treatment. Measurement of arginase expression and activity in the retina revealed a significant increase in arginase activity that was associated with increases in both mRNA and protein levels of arginase (Arg)1 but not Arg2. Immunofluorescence and flow cytometry confirmed this increase in Arg1, which was localized to glia and microglia. Arg1 expression and activity were also increased in cultured Muller cells and microglia treated with LPS. To test whether arginase has a role in the development of retinal inflammation, experiments were performed in mice deficient in one copy of the Arg1 gene and both copies of the Arg2 gene or in mice treated with a selective arginase inhibitor. These studies showed that LPS-induced increases in inflammatory protein production, leukostasis, retinal damage, signs of anterior uveitis, and uncoupling of nitric oxide synthase were blocked by either knockdown or inhibition of arginase. Furthermore, the LPS-induced increase in Arg1 expression was abrogated by blocking NADPH oxidase. In conclusion, these studies suggest that LPS-induced retinal inflammation in endotoxin-induced uveitis is mediated by NADPH oxidase-dependent increases in arginase activity.

Zhang, Wenbo; Baban, Babak; Rojas, Modesto; Tofigh, Sohrab; Virmani, Suvika K.; Patel, Chintan; Behzadian, M. Ali; Romero, Maritza J.; Caldwell, Robert W.; Caldwell, Ruth B.



Diversity of endotoxin and its impact on pathogenesis.  


Lipopolysaccharide or LPS is localized to the outer leaflet of the outer membrane and serves as the major surface component of the bacterial cell envelope. This remarkable glycolipid is essential for virtually all Gram-negative organisms and represents one of the conserved microbial structures responsible for activation of the innate immune system. For these reasons, the structure, function, and biosynthesis of LPS has been an area of intense research. The LPS of a number of bacteria is composed of three distinct regions--lipid A, a short core oligosaccharide, and the O-antigen polysaccharide. The lipid A domain, also known as endotoxin, anchors the molecule in the outer membrane and is the bioactive component recognized by TLR4 during human infection. Overall, the biochemical synthesis of lipid A is a highly conserved process; however, investigation of the lipid A structures of various organisms shows an impressive amount of diversity. These differences can be attributed to the action of latent enzymes that modify the canonical lipid A molecule. Variation of the lipid A domain of LPS serves as one strategy utilized by Gram-negative bacteria to promote survival by providing resistance to components of the innate immune system and helping to evade recognition by TLR4. This review summarizes the biochemical machinery required for the production of diverse lipid A structures of human pathogens and how structural modification of endotoxin impacts pathogenesis. PMID:16953973

Trent, M Stephen; Stead, Christopher M; Tran, An X; Hankins, Jessica V



Biophysical Mechanisms of the Neutralization of Endotoxins by Lipopolyamines  

PubMed Central

Endotoxins (lipopolysaccharides, LPS) are one of the strongest immunostimulators in nature, responsible for beneficial effects at low, and pathophysiological effects at high concentrations, the latter frequently leading to sepsis and septic shock associated with high mortality in critical care settings. There are no drugs specifically targeting the pathophysiology of sepsis, and new therapeutic agents are therefore urgently needed. The lipopolyamines are a novel class of small molecules designed to sequester and neutralize LPS. To understand the mechanisms underlying the binding and neutralization of LPS toxicity, we have performed detailed biophysical analyses of the interactions of LPS with candidate lipopolyamines which differ in their potencies of LPS neutralization. We examined gel-to-liquid crystalline phase behavior of LPS and of its supramolecular aggregate structures in the absence and presence of lipopolyamines, the ability of such compounds to incorporate into different membrane systems, and the thermodynamics of the LPS:lipopolyamine binding. We have found that the mechanisms which govern the inactivation process of LPS obey similar rules as found for other active endotoxin neutralizers such as certain antimicrobial peptides.

Sil, Diptesh; Heinbockel, Lena; Kaconis, Yani; Rossle, Manfred; Garidel, Patrick; Gutsmann, Thomas; David, Sunil A; Brandenburg, Klaus



Mifepristone (RU486) restores humoral and T cell-mediated immune response in endotoxin immunosuppressed mice  

PubMed Central

Sepsis and septic shock can be caused by Gram-positive and -negative bacteria and other microorganisms. In the case of Gram-negative bacteria, endotoxin, a normal constituent of the bacterial wall, also known as lipopolysaccharide (LPS), has been considered as one of the principal agents causing the undesirable effects in this critical illness. The response to LPS involves a rapid secretion of proinflammatory cytokines such as tumour necrosis factor (TNF)-?, interleukin (IL)-1, IL-6, interferon (IFN)-? and the concomitant induction of anti-inflammatory mediators such as IL-10, transforming growth factor (TGF)-? or glucocorticoids, which render the host temporarily refractory to subsequent lethal doses of LPS challenge in a process known as LPS or endotoxin tolerance. Although protective from the development of sepsis or systemic inflammation, endotoxin tolerance has also been pointed out as the main cause of the non-specific humoral and cellular immunosuppression described in these patients. In this report we demonstrate, using a mouse model, that mifepristone (RU486), a known glucocorticoid receptor antagonist, could play an important role in the restoration of both adaptive humoral and cellular immune response in LPS immunosuppressed mice, suggesting the involvement of endogenous glucocorticoids in this phenomenon. On the other hand, using cyclophosphamide and gemcitabine, we demonstrated that regulatory/suppressor CD4+CD25+forkhead boxP3+ and GR-1+CD11b+ cells do not play a major role in the establishment or the maintenance of endotoxin tolerance, a central mechanism for inducing an immunosuppression state.

Rearte, B; Maglioco, A; Balboa, L; Bruzzo, J; Landoni, V I; Laborde, E A; Chiarella, P; Ruggiero, R A; Fernandez, G C; Isturiz, M A



Mifepristone (RU486) restores humoral and T cell-mediated immune response in endotoxin immunosuppressed mice.  


Sepsis and septic shock can be caused by Gram-positive and -negative bacteria and other microorganisms. In the case of Gram-negative bacteria, endotoxin, a normal constituent of the bacterial wall, also known as lipopolysaccharide (LPS), has been considered as one of the principal agents causing the undesirable effects in this critical illness. The response to LPS involves a rapid secretion of proinflammatory cytokines such as tumour necrosis factor (TNF)-?, interleukin (IL)-1, IL-6, interferon (IFN)-? and the concomitant induction of anti-inflammatory mediators such as IL-10, transforming growth factor (TGF)-? or glucocorticoids, which render the host temporarily refractory to subsequent lethal doses of LPS challenge in a process known as LPS or endotoxin tolerance. Although protective from the development of sepsis or systemic inflammation, endotoxin tolerance has also been pointed out as the main cause of the non-specific humoral and cellular immunosuppression described in these patients. In this report we demonstrate, using a mouse model, that mifepristone (RU486), a known glucocorticoid receptor antagonist, could play an important role in the restoration of both adaptive humoral and cellular immune response in LPS immunosuppressed mice, suggesting the involvement of endogenous glucocorticoids in this phenomenon. On the other hand, using cyclophosphamide and gemcitabine, we demonstrated that regulatory/suppressor CD4(+) CD25(+) forkhead boxP3(+) and GR-1(+) CD11b(+) cells do not play a major role in the establishment or the maintenance of endotoxin tolerance, a central mechanism for inducing an immunosuppression state. PMID:20964639

Rearte, B; Maglioco, A; Balboa, L; Bruzzo, J; Landoni, V I; Laborde, E A; Chiarella, P; Ruggiero, R A; Fernández, G C; Isturiz, M A



Behavioral tolerance to endotoxin is enhanced by adaptation to winter photoperiods.  


Seasonal changes in day length enhance or suppress aspects of immune function in mammals. Following adaptation to short, winter-like short photoperiods, cytokine and behavioral responses to lipopolysaccharide (LPS)-induced simulated infections are attenuated in LPS-naive Siberian hamsters. This experiment examined whether diminished initial responses to LPS in short days (SDs) are accompanied by decrements in the development of innate immunological memory that leads to endotoxin tolerance. Male hamsters exposed to SDs (9h-light/day) or kept in their natal long-day (LD) photoperiod (15h-light/day) for 12-13 weeks were injected with bacterial LPS (625microg/kg, i.p.) or sterile saline. Ten days later all hamsters were challenged with LPS (625microg/kg, i.p.), and behavioral sickness responses (anorexia and reductions in nest building) were assessed. In LD hamsters, behavioral responses to the second LPS injection were markedly attenuated but still evident, indicative of partial tolerance. SD hamsters, in contrast, failed to exhibit anorexic or thermoregulatory responses to the second LPS injection, indicative of complete behavioral tolerance to LPS. Thus despite engaging greater naive responses to LPS, LD hamsters exhibited incomplete LPS tolerance relative to SD hamsters. The expression of behavioral tolerance to endotoxin is relatively diminished during the breeding season, a time of year when naive responses to endotoxin are at their greatest. During winter, enhancements in behavioral endotoxin tolerance may conserve energy and facilitate survival in the face of energetically challenging conditions. PMID:18291598

Prendergast, Brian J



Network topologies and dynamics leading to endotoxin tolerance and priming in innate immune cells.  


The innate immune system, acting as the first line of host defense, senses and adapts to foreign challenges through complex intracellular and intercellular signaling networks. Endotoxin tolerance and priming elicited by macrophages are classic examples of the complex adaptation of innate immune cells. Upon repetitive exposures to different doses of bacterial endotoxin (lipopolysaccharide) or other stimulants, macrophages show either suppressed or augmented inflammatory responses compared to a single exposure to the stimulant. Endotoxin tolerance and priming are critically involved in both immune homeostasis and the pathogenesis of diverse inflammatory diseases. However, the underlying molecular mechanisms are not well understood. By means of a computational search through the parameter space of a coarse-grained three-node network with a two-stage Metropolis sampling approach, we enumerated all the network topologies that can generate priming or tolerance. We discovered three major mechanisms for priming (pathway synergy, suppressor deactivation, activator induction) and one for tolerance (inhibitor persistence). These results not only explain existing experimental observations, but also reveal intriguing test scenarios for future experimental studies to clarify mechanisms of endotoxin priming and tolerance. PMID:22615556

Fu, Yan; Glaros, Trevor; Zhu, Meng; Wang, Ping; Wu, Zhanghan; Tyson, John J; Li, Liwu; Xing, Jianhua



Remodeling of Helicobacter pylori lipopolysaccharide.  


Modification of the lipid A domain of lipopolysaccharide (LPS) has been reported to contribute to the virulence and pathogenesis of various Gram-negative bacteria. The Kdo (3-deoxy-D-manno-octulosonic acid)-lipid A domain of Helicobacter pylori LPS shows several differences to that of Escherichia coli. It has fewer acyl chains, a reduced number of phosphate groups, much lower immunobiological activity, and only a single Kdo sugar is attached to the disaccharide backbone. However, H. pylori synthesizes a minor lipid A species resembling that of E. coli, which is both bis-phosphorylated and hexa-acylated suggesting that the major species results from the action of specific modifying enzymes. This work describes two enzymes, a lipid A phosphatase and a phosphoethanolamine transferase, involved in the periplasmic modification of the 1-position of H. pylori lipid A. Furthermore, we report a novel Kdo trimming enzyme that requires prior removal of the 1-phosphate group for enzymatic activity. Discovery of the enzymatic machinery involved in the remodeling of H. pylori LPS will help unravel the importance of these modifications in H. pylori pathogenesis. PMID:15949144

Tran, An X; Stead, Christopher M; Trent, M Stephen



Evaluation of the bacterial endotoxin test for quantification of endotoxin contamination of porcine vaccines.  


We investigated the application of the bacterial endotoxin test for the quantification of the endotoxin contamination of various commercial porcine vaccines. In endotoxin-spiked samples, Freund's complete adjuvant and aluminum hydroxide gel adjuvant failed to interfere with the results of the endotoxin test, and both recovery ratios were within the permissible range mentioned in the Japanese Pharmacopoeia. At the various dilutions tested, none of the adjuvants in commercial porcine vaccines caused noteworthy interference in the test. In addition, none of the 39 samples of porcine vaccines approved in Japan induced an interfering effect in the endotoxin test. Our findings suggest that the bacterial endotoxin test using endotoxin-specific Limulus amoebocyte lysate (LAL) can detect endotoxin contamination in commercial porcine vaccines containing either oil or aluminum adjuvants. PMID:15454187

Ogikubo, Yasuaki; Norimatsu, Mari; Noda, Ken; Takahashi, Junkichi; Inotsume, Miho; Tsuchiya, Masakazu; Tamura, Yutaka



lnterleukin-10 Inhibits Lipopolysaccharide-Induced Tumor Necrosis Factor and Interleukin1? Production in the Brain without Affecting the Activation of the Hypothalamus-Pituitary-Adrenal Axis  

Microsoft Academic Search

Interleukin (IL) 10 inhibits endotoxin (lipopolysaccharide; LPS) induced tumor necrosis factor (TNF) production in vivo and in vitro. In turn, IL-10 is induced by LPS and acts as a negative feedback to limit TNF production. We investigated the effects of IL-10 on brain TNF and IL-1? production induced by a central LPS administration in mice. Because central LPS also induces

Elena Di Santo; Marina Sironi; Pietro Pozzi; Paola Gnocchi; Anna Maria Isetta; Anne Delvaux; Michel Goldman; Arnaud Marchant; Pietro Ghezzi



Systemic Administration of Lipopolysaccharide Induces Release of Nitric Oxide and Glutamate and c-fos Expression in the Nucleus Tractus Solitarii of Rats  

Microsoft Academic Search

There is increasing recognition that communication pathways exist between the immune system and brain, which allows bidirectional regulation of immune and brain responses to infection. The endotoxin lipopolysaccharide (LPS) has been reported to elicit release of cytokines and expression of inducible nitric oxide synthase (iNOS) in peripheral organs. Whereas LPS given systemically causes endotoxic shock, little is known about its

Hui-Ching Lin; Fang-Jung Wan; Bor-Hwang Kang; Chin-Chen Wu; Ching-Jiunn Tseng


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



Annexins I and II bind to lipid A: a possible role in the inhibition of endotoxins.  

PubMed Central

Annexins are Ca2+-dependent phospholipid-binding proteins with anti-inflammatory properties that are present on the surfaces of, and released from, certain cell types, such as leukocytes and secretory epithelia. The present study investigated the possibility that annexins may bind directly to bacterial endotoxin, inhibiting its interactions with cellular receptors or accessory binding proteins. An enzyme-linked immunoassay demonstrated calcium-dependent binding of low nanomolar concentrations of annexin-I and annexin-II p36/p11 heterotetramer to lipid A. In contrast, little or no annexin binding to lipopolysaccharide (LPS) was detected under similar conditions. LPS-binding protein binding to lipid A was blocked by annexin-I, and the annexins inhibited nitrite generation in RAW 264.7 cells induced by lipid A but not that induced by LPS. The data suggest that direct binding of annexins to lipid A may represent a mechanism for suppressing cellular and systemic responses to endotoxin.

Eberhard, D A; Vandenberg, S R



Tumor necrosis factor induces GSK3 kinase-mediated cross-tolerance to endotoxin in macrophages.  


Endotoxin tolerance, a key mechanism for suppressing excessive inflammatory cytokine production, is induced by prior exposure of macrophages to Toll-like receptor (TLR) ligands. Induction of cross-tolerance to endotoxin by endogenous cytokines has not been investigated. Here we show that prior exposure to tumor necrosis factor (TNF) induced a tolerant state in macrophages, with less cytokine production after challenge with lipopolysaccharide (LPS) and protection from LPS-induced death. TNF-induced cross-tolerization was mediated by suppression of LPS-induced signaling and chromatin remodeling. TNF-induced cross-tolerance was dependent on the kinase GSK3, which suppressed chromatin accessibility and promoted rapid termination of signaling via the transcription factor NF-?B by augmenting negative feedback by the signaling inhibitors A20 and I?B?. Our results demonstrate an unexpected homeostatic function for TNF and a GSK3-mediated mechanism for the prevention of prolonged and excessive inflammation. PMID:21602809

Park, Sung Ho; Park-Min, Kyung-Hyun; Chen, Janice; Hu, Xiaoyu; Ivashkiv, Lionel B



Endotoxin and nanobacteria in polycystic kidney disease  

Microsoft Academic Search

Endotoxin and nanobacteria in polycystic kidney disease.BackgroundMicrobes have been suspected as provocateurs of polycystic kidney disease (PKD), but attempts to isolate viable organisms have failed. Bacterial endotoxin is the most often reported microbial product found in PKD fluids. We assessed potential microbial origins of endotoxin in cyst fluids from 13 PKD patients and urines of PKD and control individuals.MethodsFluids were

J. Thomas Hjelle; Marcia A. Miller-Hjelle; Ian R. Poxton; E. Olavi Kajander; Neva Ciftcioglu; Monica L. Jones; Robert C. Caughey; Robert Brown; Paul D. Millikin; Frank S. Darras



Health effects due to endotoxin inhalation (review)  

Microsoft Academic Search

Endotoxins are ubiquitous in the environment and represent important components of bioaerosols. High exposure occurs in rural\\u000a environment and at several workplaces (e.g. waste collecting, textile industry etc.). Adverse effects on human health induced\\u000a by inhalation of endotoxin are described in several studies. Up to now the endotoxin levels are mainly measured using the\\u000a Limulus amoebocyte-lysate (LAL) assay. This assay

V. Liebers; M. Raulf-Heimsoth; T. Brüning



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



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.

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



Lipopolysaccharide Binding Protein Enables Intestinal Epithelial Restitution Despite Lipopolysaccharide Exposure  

PubMed Central

Intestinal epithelial restitution is the first part in the process of mucosal repair after injury in the intestine. Integrity of the intestinal mucosal barrier is important as a first line of defense against bacteria and endotoxin. Necrotizing enterocolitis (NEC) is a major cause of morbidity and mortality in extremely low birth weight infants, but its mechanisms are not well defined. Abnormal bacterial colonization, immature barrier function, innate immunity activation and inflammation likely play a role. Lipopolysaccharide (LPS) binding protein (LBP) is secreted by enterocytes in response to inflammatory stimuli and has concentration-dependent effects. At basal concentrations, LBP stimulates the inflammatory response by presenting LPS to its receptor. However, at high concentrations, LBP is able to neutralize LPS and prevent an exaggerated inflammatory response. We sought to determine how LBP would affect wound healing in an in vitro model of intestinal cell restitution and protect against intestinal injury in a rodent model of NEC. Immature intestinal epithelial cells (IEC-6) were seeded in poly-l-lysine coated 8 chamber slides and grown to confluence. A 500?m wound was created using a cell scraper mounted on the microscope to achieve uniform wounding. Media was replaced with media containing LPS +/? LBP. Slide wells were imaged after 0, 8, and 24 hours and then fixed. Cellular restitution was evaluated via digital images captured on an inverted microscope and wound closure was determined by automated analysis. TLR4 was determined by rtPCR after RNA isolation from wounded cells 24 hours after treatment. LPS alone attenuated wound healing in immature intestinal epithelium. This attenuation is reversed by 24 hours with increasing concentrations of LBP so that wound healing is equivalent to control (p< 0.001). TLR4 was increased with LPS alone but levels returned to that of control after addition of LBP in the higher concentrations. LBP had no effect on the development of intestinal injury when given during our rodent model of NEC. Abnormal bacterial colonization and activation of innate immunity by LPS are likely involved in the pathogenesis of NEC. The attentuation of wound healing was reversed when LBP was added to LPS but only in the higher concentrations. At these same concentrations of LBP, TLR4 was decreased to that of control. These results indicate that LBP may be a novel therapeutic strategy to facilitate wound healing after the acute phase of NEC and other forms of intestinal injury.

Richter, Juli M.; Schanbacher, Brandon L.; Huang, Hong; Xue, Jianjing; Bauer, John A.; Giannone, Peter J.



Inhibition of sodium appetite by lipopolysaccharide: involvement of alpha2-adrenoceptors.  


Lipopolysaccharide (LPS), an endotoxin from the wall of Escherichia coli, produces a general behavioral inhibition and affects several aspects of fluid-electrolyte balance. LPS inhibits thirst; however, it is not clear if it also inhibits sodium appetite. The present results show that LPS (0.3-2.5 mg/kg body wt) injected intraperitoneally produces a dose-dependent reduction of sodium appetite expressed as 0.3 M NaCl intake induced by sodium depletion (furosemide plus removal of ambient sodium for 24 h). The high doses of LPS (1.2-2.5 mg/kg) also produced transient hypothermia at the beginning of the sodium appetite test; however, no dose produced hyperthermia. LPS also increased the stomach liquid content (an index of gastric emptying) after a load of 0.3 M NaCl given intragastrically by gavage to sodium-depleted rats. The ?(2)-adrenoceptor antagonist yohimbine (5 mg/kg ip) abolished the effect of LPS on 0.3 M NaCl intake, without changing the effect of LPS on gastric emptying. Injection of RX-821002 (160 nmol), another ?(2)-adrenoceptor antagonist, in the lateral cerebral ventricle (LV) also reversed the inhibition of sodium appetite produced by LPS. Yohimbine intraperitoneally or RX-821002 in the LV alone had no effect on sodium intake. Although yohimbine plus LPS produced a slight hypotension, RX-821002 plus LPS produced no change in arterial pressure, suggesting that the blockade of the effects of LPS on sodium intake by the ?(2)-adrenoceptor antagonists is independent from changes in arterial pressure. The results suggest an inhibitory role for LPS in sodium appetite that is mediated by central ?(2)-adrenoceptors. PMID:21474430

Almeida, R L; David, R B; Constancio, J; Fracasso, J F; Menani, J V; De Luca, L A



Effect of ionizing radiation on chemical and biological properties of Salmonella minnesota R595 lipopolysaccharide.  


Lipopolysaccharide of the Salmonella minnesota Re mutant R595 was irradiated with 60Co gamma doses of 50, 100, 150 and 200 kGy. The irradiated preparations were less toxic, less active in the Shwartzman reaction and as activators of the complement system, but they had retained the protection activity against the lethal action of endotoxin. The irradiation resulted in a dose-dependent decrease in the amounts of constituents (glucosamine, KDO, fatty acids) of the original lipopolysaccharide. With increasing irradiation doses increasing amounts of the irradiated material became dialysable (up to 21% in the 200 kGy sample). Only 50% of total fatty acids were present in the 200 kGy preparation compared to the parent lipopolysaccharide. The degradation products formed during irradiation have not been identified. PMID:7185268

El Sabbagh, M; Galanos, C; Bertók, L; Füst, G; Lüderitz, O



Greater hypoxia-induced cell death in prenatal brain after bacterial-endotoxin pretreatment is not because of enhanced cerebral energy depletion: a chicken embryo model of the intrapartum response to hypoxia and infection  

Microsoft Academic Search

Infection is a risk factor for adult stroke and neonatal encephalopathy. We investigated whether exposure to bacterial endotoxin increases hypoxia-induced brain cell death and impairs cerebral metabolic compensatory responses to hypoxia. Prehatching chicken embryos (incubation day 19) were exposed to bacterial lipopolysaccharide (LPS) (3 mg Salmonella typhimurium LPS per egg) or hypoxia (4% ambient O2 for 1 h), alone or

Xiaolan Wang; David W Carmichael; Ernest B Cady; Oliver Gearing; Alan Bainbridge; Roger J Ordidge; Gena Raivich; Donald M Peebles



Immunochemical characterization of rough Brucella lipopolysaccharides.  

PubMed Central

Lipopolysaccharides (LPS) were extracted from rough strains of Brucella abortus and Brucella melitensis and from strains of the naturally occurring rough species Brucella ovis and Brucella canis. Brucella rough lipopolysaccharides (R-LPS) were readily distinguished from Brucella smooth lipopolysaccharides (S-LPS) and enterobacterial R-LPS, by their chemical, physical, and serological characteristics. B. ovis R-LPS was differentiated from B. abortus, B. melitensis, and B. canis R-LPS by its reaction of partial identity in immunodiffusion. Monospecific mouse sera against B. ovis R-LPS agglutinated only the homologous bacteria but not R cells of other species of Brucella. B. ovis R-LPS contained more 2-keto, 3-deoxyoctonate, and glucosamine as a percentage of dry weight than any other R-LPS tested. B. abortus R-LPS was identified by the absence of an unidentified sugar present in the other R-LPS molecules, and B. melitensis R-LPS could be differentiated from B. canis R-LPS by its higher content of fatty acids. In contrast to S-LPS, all of the R-LPS studied lacked quinovosamine. In electron micrographs, Brucella R-LPS had a granular appearance, in contrast to typical lamellar structures formed by Brucella S-LPS and Escherichia coli R-LPS. Images

Moreno, E; Jones, L M; Berman, D T



Lipopolysaccharides: From Erinyes to Charites  

PubMed Central

Following the discovery of endotoxins by Richard Pfeiffer, such bacterial product was associated to many severe disorders produced by an overwhelming inflammatory response and often resulting in endotoxic shock and multiple organ failure. However, recent clinical and basic sciences investigations claimed some beneficial roles of typical as well as atypical endotoxins. The aim of this paper is to focus on recent data supporting a beneficial activity of both typical and atypical endotoxins. Such novel perspective looks promising for development of new drugs for prevention and therapy of several human diseases.

Foca, Alfredo; Liberto, Maria Carla; Quirino, Angela; Matera, Giovanni



Radio-detoxified endotoxin activates natural immunity: A review  

Microsoft Academic Search

It is well demonstrated that serial endotoxin injections produce endotoxin tolerance and elevate the natural immunity\\/resistance. However, such injections may also have harmful effects such as high fever, hypotension and abortion. For this reason endotoxin (LPS) injections are not suitable to enhance nonspecific resistance in endotoxin-sensitive species like man. Various techniques have been designed (physical, chemical, etc.) for the detoxification

Lóránd Bertók



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



Airborne Endotoxins: An Association with Occupational Lung Disease  

Microsoft Academic Search

Endotoxins are a component of the cell wall of gram negative bacteria and have been implicated as the etiological agent of byssinosis as well as the cause of pulmonary responses attributed to other organic dusts. Recent studies have proposed threshold values for airborne endotoxin and suggest that consideration be given to developing an occupational standard for endotoxin. Endotoxins occur at

Robert R. Jacobs



Lipopolysaccharide priming enhances expression of effectors of immune defence while decreasing expression of pro-inflammatory cytokines in mammary epithelia cells from cows  

PubMed Central

Background Udder infections with environmental pathogens like Escherichia coli are a serious problem for the dairy industry. Reduction of incidence and severity of mastitis is desirable and mild priming of the immune system either through vaccination or with low doses of immune stimulants such as lipopolysaccharide LPS was previously found to dampen detrimental effects of a subsequent infection. Monocytes/macrophages are known to develop tolerance towards the endotoxin LPS (endotoxin tolerance, ET) as adaptation strategy to prevent exuberant inflammation. We have recently observed that infusion of 1 ?g of LPS into the quarter of an udder effectively protected for several days against an experimentally elicited mastitis. We have modelled this process in primary cultures of mammary epithelial cells (MEC) from the cow. MEC are by far the most abundant cells in the healthy udder coming into contact with invading pathogens and little is known about their role in establishing ET. Results We primed primary MEC cultures for 12 h with LPS (100 ng/ml) and stimulated three cultures either 12 h or 42 h later with 107/ml particles of heat inactivated E. coli bacteria for six hours. Priming-related alterations in the global transcriptome of those cells were quantified with Affymetrix microarrays. LPS priming alone caused differential expression of 40 genes and mediated significantly different response to a subsequent E. coli challenge of 226 genes. Expression of 38 genes was enhanced while that of 188 was decreased. Higher expressed were anti-microbial factors (?-defensin LAP, SLPI), cell and tissue protecting factors (DAF, MUC1, TGM1, TGM3) as well as mediators of the sentinel function of MEC (CCL5, CXCL8). Dampened was the expression of potentially harmful pro-inflammatory master cytokines (IL1B, IL6, TNF-?) and immune effectors (NOS2, matrix metalloproteases). Functional network analysis highlighted the reduced expression of IL1B and of IRF7 as key to this modulation. Conclusion LPS-primed MEC are fitter to repel pathogens and better protected against misguided attacks of the immune response. Attenuated is the exuberant expression of factors potentially promoting immunopathological processes. MEC therefore recapitulate many aspects of ET known so far from professional immune cells.



Recombinant fibronectin polypeptide antagonizes hepatic failure induced by endotoxin in mice1  

Microsoft Academic Search

AIM: To study the preventive effect of recombinant human fibronectin (rhFN) polypeptide on hepatic failure in- duced by endotoxin in mice. METHODS: A cDNA fragment coding for Ile1363-Tyr1725 of human FN was inserted into the PinPoint Xa-3 plasmid, and the constructed plasmid was transformed into E coli BL21 (DE3) cells, and then the expression of rhFN polypeptide in DE3 cells

Yong WU; Yuan-zhong CHEN; Hui-fang HUANG; Ping CHEN


Systemic Administration of Lipopolysaccharide Induces Cyclooxygenase2 Immunoreactivity in Endothelium and Increases Microglia in the Mouse Hippocampus  

Microsoft Academic Search

In this study, we observed the effects of lipopolysaccharide (LPS) on neurodegeneration and immune response in the hippocampus.\\u000a LPS is a gram-negative bacterial cell surface proteoglycan and known as a bacterial endotoxin. For this, we investigated the\\u000a optimal concentration of LPS influencing the ICR mouse hippocampus to measure the LPS receptor, e.g., toll-like receptor 4\\u000a (TLR4), expression in mouse hippocampal

Dae Won Chung; Ki-Yeon Yoo; In Koo Hwang; Dae Won Kim; Jin Young Chung; Choong Hyun Lee; Jung Hoon Choi; Soo Young Choi; Hwa Young Youn; In Se Lee; Moo-Ho Won



Bacterial lipopolysaccharide induces expression of ABCA1 but not ABCG1 via an LXR-independent pathway  

Microsoft Academic Search

Two ATP-binding cassette transporter proteins, ABCA1 and ABCG1, may mediate an active efflux of cellu- lar cholesterol and phospholipids. They are ubiquitously ex- pressed and are subject to regulation by cholesterol loading or by treatment with agents that activate the nuclear hor- mone receptor LXR. Earlier studies in both primates and non-primates reported that treatment with endotoxin (bac- terial lipopolysaccharide,

Rebecca Kaplan; Xiaodong Gan; John G. Menke; Samuel D. Wright; Tian-Quan Cai


Effect of concurrent intratracheal lipopolysaccharide and human serum albumin challenge on primary and secondary antibody responses in poultry  

Microsoft Academic Search

Activation of the innate immune system by pathogen-associated molecular patterns (PAMPs) may direct specific immune responses and as a consequence probably significantly affect vaccination. Previously, we described modulation of specific antibody responses to systemically administered model antigens by intravenously (i.v.) as well as intratracheally (i.t.) administered PAMP such as the endotoxin lipopolysaccharide (LPS). In this study effects of various doses

H. K. Parmentier; A. L. Klompen; G. De Vries Reilingh; A. Lammers



Tissue-specific cytokine release from human extraplacental membranes stimulated by lipopolysaccharide in a two-compartment tissue culture system  

Microsoft Academic Search

BACKGROUND: The extra-placental gestational membranes secrete cytokines in response to bacteria and other infectious agents, with potentially adverse consequences for pregnancy. The present study used lipopolysaccharide (LPS) as a prototype endotoxin to investigate the pattern of stimulated cytokine release from the amniotic and choriodecidual sides of full-thickness human gestational membranes in a two-compartment tissue culture system. METHODS: Gestational membranes were

Natalie W Thiex; Mark C Chames; Rita K Loch-Caruso




PubMed Central

The mouse mammary tumor MT 296 was used in a further series of experiments on the implantation of tumor, plated out in vivo, from suspensions of individual cells. Lipopolysaccharide from S. typhosa was shown to exert an adjuvator influence. But this adjuvator, an endotoxin, had no direct effect on the suspended tumor cells, unlike the liver preparations previously reported. Lipopolysaccharide from S. typhosa was shown to act on the host. It made the host's connective tissue expanses more susceptible to successful implantation by the tumor cells. It did this only if present at the time these connective tissue expanses were split. The increased susceptibility, caused by splitting the connective tissue expanses in the presence of lipopolysaccharide, declined quickly after 24 hr. The structural changes wrought upon the connective tissues by splitting them in the presence of lipopolysaccharide are described. They show kinship to a Schwartzman reaction of the local type. Their possible role in the adjuvator effect on the plating of single cell suspensions of this tumor is discussed.

Henderson, James Stuart




PubMed Central

In vitro secretion of glycocorticoids by adrenal glands pooled from several control mice was compared with that of glands removed from animals following injections of either ACTH or endotoxin. Both substances prevent glycocorticoid synthesis stimulated in vitro with ACTH. Cholesterol content of adrenal glands under these conditions was nearly depleted, indicating maximal response to ACTH or endotoxin prior to their removal for the in vitro tests. In an effort to account physiologically for the manner in which endotoxin suppresses or prevents the rise in urinary nitrogen excreted in response to ACTH, blood non-protein nitrogen levels (NPN) were determined. The following experimental conditions resulted in increased urinary nitrogen excretion but did not alter blood NPN: cortisone given alone or at the same time as endotoxin; ACTH alone; dichloroisoproterenol (DCI) given concurrently with endotoxin; and lactalbumin digest injected intraperitoneally. Increases (2- to 3-fold) in blood NPN were observed when endotoxin was given alone, concurrently with ACTH, or 3 hours prior to cortisone, DCI, or lactalbumin digest. Urinary nitrogen excretion showed no change under these conditions. The elevation in blood NPN in endotoxin-poisoned mice was found to be due almost entirely to urea nitrogen and not to amino acid nitrogen or to other nitrogenous wastes. Blood clearance of mulin, phenol red excretion, and urea elimination were each determined in control and in endotoxin-poisoned mice. The latter mice showed impaired renal function. Treatment with diuretics (diuril and aminophylline) failed to alter oliguria or elevated blood NPN. Hydergine treatment was also without effect. Total carcass NPN and urinary nitrogen excretion data were combined to give a picture of total protein catabolized by mice under different experimental conditions. Cortisone injected at the same time as endotoxin or 3 hours later resulted in the same increase in total NPN. However, in the former case all the extra nitrogen appeared in the urine while in the latter it remained in the carcass. ACTH given alone or concurrently with endotoxin produced large increases in total NPN but less in poisoned mice. This suggests that endotoxin suppresses adrenal response to ACTH. Urea injected into normal mice was recovered quantitatively in urine while in endotoxin-poisoned mice it was partitioned between carcass and urine. Elevation of carcass NPN by means of urea injections failed to alter the lethality of an LD70 dose of endotoxin.

Berry, L. Joe; Smythe, Dorothy S.



Lipopolysaccharides of Rhizobium  

Microsoft Academic Search

Hot phenol-water extractions were carried out of cells from 12 strains of the fast-growing rhizobia Rhizobium leguminosarum, Rhizobium phaseoli, Rhizobium trifolii and Rhizobium meliloti. Purified lipopolysaccharide preparations contain neutral sugars, hexosamines, 2-keto-3-deoxyoctonate and uronic acids. Glucose, galactose, mannose, rhamnose and fucose are present in the majority of the LPS-preparations, but in varying proportions. Heptose was only found in some of

L. P. T. M. Zevenhuizen; Ineke Scholten-Koerselman; M. A. Posthumus



Isoforskolin pretreatment attenuates lipopolysaccharide-induced acute lung injury in animal models.  


Isoforskolin was isolated from Coleus forskohlii native to Yunnan in China. We hypothesize that isoforskolin pretreatment attenuates acute lung injury induced by lipopolysaccharide (endotoxin). Three acute lung injury models were used: situ perfused rat lung, rat and mouse models of endotoxic shock. Additionally, lipopolysaccharide stimulated proinflammatory cytokine production was evaluated in human mononuclear leukocyte. In situ perfused rat lungs, pre-perfusion with isoforskolin (100, and 200 ?M) and dexamethasone (65 ?M, positive control) inhibited lipopolysaccharide (10 mg/L) induced increases in lung neutrophil adhesion rate, myeloperoxidase activity, lung weight Wet/Dry ratio, permeability-surface area product value, and tumor necrosis factor (TNF)-? levels. In rats, pretreatments with isoforskolin (5, 10, and 20 mg/kg, i.p.) and dexamethasone (5mg/kg, i.p.) markedly reduced lipopolysaccharide (6 mg/kg i.v.) induced increases of karyocyte, neutrophil counts and protein content in bronchoalveolar lavage fluid, and plasma myeloperoxidase activity. Lung histopathology showed that morphologic changes induced by lipopolysaccharide were less pronounced in the isoforskolin and dexamethasone pretreated rats. In mice, 5 mg/kg isoforskolin and dexamethasone caused 100% and 80% survival, respectively, after administration of lipopolysaccharide (62.5mg/kg, i.v., 40% survival if untreated). In human mononuclear leukocyte, isoforskolin (50, 100, and 200 ?M) and dexamethasone (10 ?M) pre-incubation lowered lipopolysaccharide (2 ?g/mL) induced secretion of the cytokine TNF-?, and interleukins (IL)-1?, IL-6, and IL-8. In conclusion, pretreatment with isoforskolin attenuates lipopolysaccharide-induced acute lung injury in several models, and it is involved in down-regulation of inflammatory responses and proinflammatory cytokines TNF-?, IL-1?, IL-6, and IL-8. PMID:21272678

Yang, Weimin; Qiang, Dongjin; Zhang, Min; Ma, Limei; Zhang, Yonghui; Qing, Chen; Xu, Yunlong; Zhen, Chunlan; Liu, Jikai; Chen, Yan-Hua



Novel Bacillus thuringiensis ?-endotoxin active against Locusta migratoria manilensis.  


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 (LC??s) 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



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.

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



Endotoxins from Cyanobacteria and Gram-negative Bacteria as the Cause of an Acute Influenza-like Reaction after Inhalation of Aerosols  

Microsoft Academic Search

Endotoxins (lipopolysaccharides) in aerosols, originating from cyanobacteria and gram-negative bacteria, were the likely etiological agent behind outbreaks of a transient, flu-like syndrome, described from four Scandinavian towns and Harare, Zimbabwe. The syndrome with fever, malaise, muscle pains, tightness of the chest and respiratory-tract symptoms, also known as toxic pneumonitis, occurred 1.5–6 hours after taking a bath or shower. The outbreaks

Heléne Annadotter; Gertrud Cronberg; Rolf Nystrand; Ragnar Rylander



Chronic intrauterine exposure to endotoxin does not alter fetal nephron number or glomerular size.  


A reduced nephron endowment early in life adversely impacts on long-term functional reserve in the kidney. A recent study has shown that acute exposure to chorioamnionitis during late gestation can adversely impact on nephrogenesis. The present study aimed to examine the effects of chronic, low-dose endotoxin exposure in utero, during the period of nephrogenesis, on nephron number and glomerular size in preterm lambs. ?Ewes were administered either endotoxin (lipopolysaccharide; 1 mg/day) or saline at 110-133 days of gestation (term approximately 147 days) via surgically implanted osmotic minipumps within the amniotic cavity. The ewes were induced to deliver preterm at 133 days gestation and the kidneys of the lambs were analysed at 8 weeks after term-equivalent age. Nephron number per kidney was determined using a combined optical disector and fractionator stereological approach; renal corpuscle size was also measured stereologically. ?At 8 weeks after term-equivalent age there was no significant effect of in utero exposure to endotoxin on bodyweight or kidney weight and there were no significant differences in nephron number, nephron density or renal corpuscle volume between groups. ?We conclude that chronic intrauterine inflammation during the period of nephrogenesis may not adversely impact on the number of nephrons formed within the kidney or on the volume of the renal corpuscle. PMID:23586487

Ryan, Danica; Atik, Anzari; De Matteo, Robert; Harding, Richard; Black, Mary J



Differential effects of glucocorticoids in the establishment and maintenance of endotoxin tolerance.  


Gram-negative infections can result in endotoxic shock, which is the most common cause of death in intensive care units. Most of the undesirable effects in sepsis and septic shock have been ascribed to lipopolysaccharide (LPS), a normal constituent of the bacterial wall. The response to LPS involves rapid secretion of proinflammatory cytokines [tumour necrosis factor-alpha, interleukin (IL)-1, IL-6, IL-8, interferon-gamma] and the concomitant induction of anti-inflammatory mediators such as IL-10 and transforming growth factor-beta and glucocorticoids (GC), which render the host temporarily refractory to subsequent lethal doses of LPS challenge in a process known as LPS or endotoxin tolerance. Although protective from the development of sepsis or systemic inflammation, endotoxin tolerance has also been pointed out as the principal cause of the non-specific immunosuppression described in these patients. In this report we demonstrate, using a mouse model, that while the maintenance of tolerance is dependent upon GC, the establishment of tolerance by LPS could be inhibited by dexamethasone (Dex), a synthetic GC. Conversely, we demonstrated that mifepristone (RU486), a known GC receptor antagonist, was capable of inducing a transient and reversible disruption of endotoxin tolerance, also permitting partial restoration of the humoral immune response in LPS tolerant/immunosuppressed mice. These results are encouraging for the management of immunosuppression in sepsis and/or non-infectious shock, and deserve further investigation in the future. PMID:19912256

Rearte, B; Landoni, V; Laborde, E; Fernández, G; Isturiz, M



Differential effects of glucocorticoids in the establishment and maintenance of endotoxin tolerance  

PubMed Central

Gram-negative infections can result in endotoxic shock, which is the most common cause of death in intensive care units. Most of the undesirable effects in sepsis and septic shock have been ascribed to lipopolysaccharide (LPS), a normal constituent of the bacterial wall. The response to LPS involves rapid secretion of proinflammatory cytokines [tumour necrosis factor-?, interleukin (IL)-1, IL-6, IL-8, interferon-?] and the concomitant induction of anti-inflammatory mediators such as IL-10 and transforming growth factor-? and glucocorticoids (GC), which render the host temporarily refractory to subsequent lethal doses of LPS challenge in a process known as LPS or endotoxin tolerance. Although protective from the development of sepsis or systemic inflammation, endotoxin tolerance has also been pointed out as the principal cause of the non-specific immunosuppression described in these patients. In this report we demonstrate, using a mouse model, that while the maintenance of tolerance is dependent upon GC, the establishment of tolerance by LPS could be inhibited by dexamethasone (Dex), a synthetic GC. Conversely, we demonstrated that mifepristone (RU486), a known GC receptor antagonist, was capable of inducing a transient and reversible disruption of endotoxin tolerance, also permitting partial restoration of the humoral immune response in LPS tolerant/immunosuppressed mice. These results are encouraging for the management of immunosuppression in sepsis and/or non-infectious shock, and deserve further investigation in the future.

Rearte, B; Landoni, V; Laborde, E; Fernandez, G; Isturiz, M



Vitamin E inhibits endotoxin-mediated transport of phosphatases to lipid rafts.  


The production and release of inflammatory mediators is regulated by the coordinated activity of kinases and phosphatases. These proteins are known to regulate one another through an unknown mechanism. Previously, we have demonstrated that autocrine release of oxidants regulates macrophage activation in a similar fashion. The purpose of this study is to determine if attenuated oxidant activity by antioxidant exposure can regulate endotoxin-mediated kinase and phosphatase activity. Human promonocytic THP-1 cells were stimulated with lipopolysaccharide. Selected cells were pretreated with alpha-tocopherol succinate, LY294002, or an AKT inhibitor (1L-6-hydroxymethyl-chiro-inositol 2-(R)-2-O-methyl-3-O-octadecylcarbonate). Lipid raft and cellular protein were analyzed for lipid raft toll-like receptor 4 (TLR4) receptor formation and mitogen-activated protein kinase (MAPK) activation. Harvested supernatants were analyzed for tumor necrosis factor (TNF)-alpha production. Lipopolysaccharide stimulation led to the lipid raft mobilization of TLR4 and heat shock protein 70. This was followed by lipid raft mobilization of SH related complex homology 2 domain-containing inositol-5-phosphate (SHIP), activation of the MAPK, and production of TNF-alpha. Pretreatment with alpha-tocopherol succinate did not affect mobilization of TLR4 or heat shock protein 70, but did result in attenuated mobilization of SHIP, activation of the MAPK, and production of TNF-alpha. In addition, alpha-tocopherol succinate was associated with increased activation of the counter-regulatory kinase protein kinase B. Pretreatment with LY294002 or 1L-6-hydroxymethyl-chiro-inositol 2-(R)-2-O-methyl-3-O-octadecylcarbonate reversed the effects of alpha-tocopherol succinate. Thus, it seems that endotoxin-mediated activation requires the coordinated activity of kinases and phosphatases. Antioxidant exposure in the form of vitamin E seems to attenuate endotoxin-mediated SHIP activation resulting in increased AKT activity, and attenuated MAPK activation and TNF-alpha production. PMID:17172975

Cuschieri, Joseph; Bulger, Eileen; Biligren, Jens; Garcia, Iris; Maier, Ronald V



The development of endotoxin tolerance, and the role of hypothalamo-pituitary-adrenal function and glucocorticoids in Pekin ducks.  


Endotoxin tolerance represents a state of abated immunological responsiveness to pyrogens, which, in mammals, leads to the decline or abolition of the fever response. The development of endotoxin tolerance in birds is not well understood; consequently, the impact of repeated pathogenic exposure on the avian febrile response, and thus on the ability of birds to fight recurrent infection, is not known. We determined the effect of repeated injections of lipopolysaccharide (LPS) on the febrile response of Pekin ducks. We gave ducks five injections of LPS, spaced 1, 4 or 10 days apart, and recorded their core body temperature with abdominally implanted temperature data loggers. Once we established that Pekin ducks developed endotoxin tolerance, we investigated the effect of repeated injections of LPS on the central and peripheral segments of the hypothalamo-pituitary-adrenal (HPA) axis in an attempt to elucidate the role of glucocorticoids in the modulation of the febrile response during the tolerant period. When our ducks became tolerant to LPS, they had significantly higher basal levels of plasma corticosterone (CORT, the principal glucocorticoid in birds), and their HPA response to treatment with LPS was blunted. We propose that the augmented levels of basal plasma CORT resulted from sensitized HPA function, and this, in turn, contributed to the development of endotoxin tolerance. Regulation of the circulating level of CORT might be a possible target for the re-establishment of appropriate immune responses in birds. PMID:21957101

Marais, Manette; Maloney, Shane K; Gray, David A



Effect of naloxone on regional cerebral blood flow during endotoxin shock in conscious rats  

SciTech Connect

Maintenance of cerebral blood flow (CBF) is vital during cardiovascular shock. Since opioids have been implicated in the pathophysiology of endotoxin shock and have been shown to alter cerebral perfusion patterns, the authors determined whether opioids were responsible for any of the changes in regional CBF observed during endotoxin shock and whether the use of naloxone might impair or aid in the maintenance of CBF. When blood flow (BF) is studied with radioactively-labeled microspheres in rats, the left ventricle of the heart is often cannulated via the right carotid artery. Questions have arisen concerning the potential adverse effects of this method on CBF in the hemisphere ipsilateral to the ligated artery. They measured right and left regional CBF by use of this route of cannulation. Twenty-four hours after cannulations were performed, flow measurements were made using radiolabeled microspheres in conscious unrestrained male Sprague-Dawley rats (300-400 g) before and 10, 30, and 60 min after challenging with 10 mg/kg Escherichia coli endotoxin (etx) or saline. Naloxone (2 mg/kg) or saline was given as a treatment 25 min post-etx. They found no significant differences between right and left cortical, midbrain, or cerebellar BF at any time in any treatment group. Therefore naloxone treatment of endotoxin shock may be beneficial in preventing decreases in regional CBF.

Law, W.R.; Ferguson, J.L. (Univ. of Illinois, Chicago (USA))



Role of nitric oxide in tolerance to lipopolysaccharide in mice.  


The injection of repeated doses of lipopolysaccharide (LPS) results in attenuation of the febrile response, which is called endotoxin tolerance. We tested the hypothesis that nitric oxide (NO) arising from inducible NO synthase (iNOS) plays a role in endotoxin tolerance, using not only pharmacological trials but also genetically engineered mice. Body core temperature was measured by biotelemetry in mice treated with NG-monomethyl-L-arginine (L-NMMA, 40 mg/kg; a nonselective NO synthase inhibitor) or aminoguanidine (AG, 10 mg/kg; a selective iNOS inhibitor) and in mice deficient in the iNOS gene (iNOS KO) mice. Tolerance to LPS was induced by means of three consecutive LPS (100 microg/kg) intraperitoneal injections at 24-h intervals. In wild-type mice, we observed a significant reduction of the febrile response to repeated administration of LPS. Injection of L-NMMA and AG markedly enhanced the febrile response to LPS in tolerant animals. Conversely, iNOS-KO mice repeatedly injected with LPS did not become tolerant to the pyrogenic effect of LPS. These data are consistent with the notion that NO modulates LPS tolerance in mice and that iNOS isoform is involved in NO synthesis during LPS tolerance. PMID:15579566

Dias, Mirela B; Almeida, Maria C; Carnio, Evelin C; Branco, Luiz G S



Comparison of Endotoxin Assays Using Agricultural Dusts  

Microsoft Academic Search

Endotoxins from gram-negative bacteria pose a significant respiratory hazard. Establishing dose-response relationships is problematic because there are no standard procedures for sampling and analysis. The goal of this study was to compare endotoxin analyses in six laboratories using Limulus-based assays for analysis of organic dusts from three agricultural environments: chicken barns, swine barns, and corn processing facilities. For each dust

Stephen J. Reynolds; Peter S. Thorne; Kelley J. Donham; Elizabeth A. Croteau; Kevin M. Kelly; Daniel Lewis; Mike Whitmer; D. J. J. Heederik; Jeroen Douwes; Ian Connaughton; Sharon Koch; Per Malmberg; Britt-Marie Larsson; Donald K. Milton



MicroRNA-98 negatively regulates IL-10 production and endotoxin tolerance in macrophages after LPS stimulation.  


Interleukin 10 (IL-10) is a potent anti-inflammatory cytokine that is crucial for dampening the inflammatory response after pathogen invasion, and was found to be produced by macrophages after exposure to lipopolysaccharide (LPS). It remains unclear whether microRNA-mediated regulatory mechanism is involved in LPS-induced IL-10 production. Here we reported that miR-98 expression in macrophages significantly decreased following LPS stimulation. We also found that miR-98 targets the 3'untranslated region of IL-10 transcript. Overexpression of miR-98 inhibited TLR4-triggered IL-10 production and promoted COX-2 expression. We further demonstrated that miR-98 significantly mitigated the induction of endotoxin tolerance, suggesting that miR-98-mediated posttranscriptional control could potentially be involved in fine tuning the critical level of IL-10 production in endotoxin tolerance. PMID:21609717

Liu, Yang; Chen, Qingyun; Song, Yinjing; Lai, Lihua; Wang, Jianli; Yu, Hai; Cao, Xuetao; Wang, Qingqing



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.




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


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

Murakami, Taisuke; Suzuki, Kaori; Tamura, Hiroshi; Nagaoka, Isao



Humoral glycolipid is associated with mouse memory impairment caused by lipopolysaccharide.  


Mouse memory impairment induced by repeated daily dosing of lipopolysaccharide from Escherichia coli 044 was investigated using a passive avoidance method. One dose of 25 mg/kg or 8 repeated daily doses of 2.5 mg/kg of the lipopolysaccharide impaired the memory of 6-week-old male ddY mice. The chemical structure of the lipopolysaccharide was polymannoses Gal?1-3GalNAc-lipid A. Humoral polymannose-lipid reactivity was not found in lipopolysaccharide or in control mice receiving repeated daily doses of physiological saline. Humoral glycolipid with Gal?1-3GalNAc reactivity was found in the mice repeatedly treated with the lipopolysaccharide but not in the control mice repeatedly treated with physiological saline. Intraperitoneal injection of the humoral glycolipid did not impair memory in the normal mice, but mice treated beforehand with the glycolipid showed memory impairment after a subsequent single injection of 2.5 mg/kg of the lipopolysaccharide. These findings suggest that the polymannose component of the lipopolysaccharide is closely associated with the memory impairment effect and that the humoral glycolipid is a subsidiary metabolite of the lipopolysaccharide. PMID:23594485

Masuda, Yutaka; Sugiyama, Toshihiro



The effect of meloxicam on pain sensitivity, rumination time, and clinical signs in dairy cows with endotoxin-induced clinical mastitis.  


The objectives of this study were to (1) evaluate the use of a pressure algometer and an automated rumination monitoring system to assess changes in pain sensitivity and rumination time in response to endotoxin-induced clinical mastitis and (2) evaluate the effect of the nonsteroidal antiinflammatory drug meloxicam on pain sensitivity and rumination time, as well as other clinical signs, in dairy cattle with endotoxin-induced clinical mastitis. Clinical mastitis was induced in 12 primiparous and 12 multiparous lactating dairy cows by intramammary infusion of 25 µg of Escherichia coli lipopolysaccharide (LPS) into 1 uninfected quarter. Immediately after, half the cows were injected subcutaneously with meloxicam (treated group) and half with the same volume of a placebo solution (control group). Pain sensitivity was assessed by measuring the difference in pressure required to elicit a response on the control and challenged quarter using an algometer 3 d before, immediately before, and at 3, 6, 12, and 24h after LPS infusion and either meloxicam or placebo injection. Rumination was continuously monitored from 2 d before to 3 d after LPS infusion using rumination loggers. Udder edema, body temperature, somatic cell score, and dry matter intake were also monitored to evaluate the occurrence and the duration of the inflammation after LPS infusion. In control animals, the difference in the pressure applied to the control and challenged quarters (control - challenged quarter) increased by 1.1 ± 0.4 kg of force 6h after LPS infusion compared with the baseline, suggesting an increase in pain sensitivity in the challenged quarter. Neither the LPS infusion nor the meloxicam treatment had an effect on daily rumination time. However, the rumination diurnal pattern on the day of LPS infusion showed an overall deviation from the baseline pattern. Cows spent less time ruminating in the hours following LPS infusion and more time ruminating later in the day. Meloxicam did not alter somatic cell score or dry matter intake. However, meloxicam-treated animals had less udder edema and a lower body temperature in the hours following LPS infusion compared with control animals. In conclusion, pressure algometers and rumination loggers show promise as tools to detect mastitis and monitor recovery on farm. Further, meloxicam has a beneficial effect in relieving pain and decreasing udder edema and body temperature in LPS-induced clinical mastitis. PMID:23522672

Fitzpatrick, C E; Chapinal, N; Petersson-Wolfe, C S; DeVries, T J; Kelton, D F; Duffield, T F; Leslie, K E



Effect of Aspartame on Oxidative Stress and Monoamine Neurotransmitter Levels in Lipopolysaccharide-Treated Mice  

Microsoft Academic Search

This study aimed at investigating the effect of the sweetener aspartame on oxidative stress and brain monoamines in normal\\u000a circumstances and after intraperitoneal (i.p.) administration of lipopolysaccharide (LPS; 100 ?g\\/kg) in mice. Aspartame (0.625–45 mg\\/kg)\\u000a was given via subcutaneous route at the time of endotoxin administration. Mice were euthanized 4 h later. Reduced glutathione\\u000a (GSH), lipid peroxidation (thiobarbituric acid-reactive substances; TBARS), and nitrite

Omar M. E. Abdel-SalamNeveen; Neveen A. Salem; Jihan Seid Hussein


Acute on chronic exposure to endotoxin in preterm fetal sheep.  


Acute, high-dose exposure to endotoxin lipopolysaccharide (LPS) in preterm fetal sheep can trigger periventricular white matter lesions (PVL), in association with severe hypotension/hypoxemia and significant mortality. Intriguingly, however, chronic or repeated exposure to LPS can induce tachyphylaxis. We therefore tested the hypothesis that progressive, acute on chronic fetal infection would be associated with white matter injury with little fetal mortality. Chronically instrumented preterm (0.7 gestational age) fetal sheep were exposed to a continuous low-dose LPS infusion (100 ng over 24 h, followed by 250 ng/24 h for 96 h) or saline. Boluses of 1 ?g LPS or saline were given at 48, 72, and 96 h; sheep were killed at day 10. Six of 11 fetal sheep exposed to saline infusion + LPS boluses died 4-7 h after the first bolus. In contrast, there was no fetal mortality after saline infusions alone (n = 9), low-dose LPS infusion + saline boluses (n = 5), or low-dose LPS + LPS boluses (n = 9). Low-dose LPS infusion + LPS boluses was associated with greater microglial induction than low-dose LPS + saline boluses but a similar area of periventricular white matter inflammation. One fetus developed severe focal white matter necrosis after LPS infusion + boluses. The acute cardiovascular compromise associated with high-dose, acute exposure to LPS is markedly attenuated by previous low-dose infusions, with limited apparent exacerbation of periventricular white matter injury compared with low-dose infusion alone. PMID:23235324

Mathai, Sam; Booth, Lindsea C; Davidson, Joanne O; Drury, Paul P; Fraser, Mhoyra; Jensen, Ellen C; George, Sherly; Naylor, Andrew; Gunn, Alistair J; Bennet, Laura



Noncovalent Complex Vaccine, Prepared with Detoxified Escherichia coli J5 (Rc Chemotype) Lipopolysaccharide and Neisseria meningitidis Group B Outer Membrane Protein, Produces Protective Antibodies against Gram-Negative Bacteremia.  

National Technical Information Service (NTIS)

Earlier studies showed that purified IgG from sera of rabbits immunized with a boiled Escherichia coli J5 (Rc chemotype) whole cell vaccine protected neutropenic rats against gram-negative bacterial sepsis. In the present study, de-O-acylated J5 lipopolys...

A. K. Bhattacharjee S. M. Opal R. Taylor R. Naso M. Semenuk



Endotoxin Quantitation by Measurement of Non-Precipitated Limulus Proteins.  

National Technical Information Service (NTIS)

Using the Limulus Amoebocyte Lysate test a number of procedures have been developed for the quantitation of endotoxin. This report introduces a new method based on the relationship between non-precipitated limulus proteins and endotoxin. Using this relati...

D. A. DuBose J. M. Brown



Altered Toll-like Receptor 2-mediated Endotoxin Tolerance Is Related to Diminished Interferon ? Production  

PubMed Central

Induction of endotoxin tolerance leads to a reduced inflammatory response after repeated challenge by LPS and is important for resolution of inflammation and prevention of tissue damage. Enterobacterial LPS is recognized by the TLR4 signaling complex, whereas LPS of some non-enterobacterial organisms is capable of signaling independently of TLR4 utilizing TLR2-mediated signal transduction instead. In this study we report that Porphyromonas gingivalis LPS, a TLR2 agonist, fails to induce a fully endotoxin tolerant state in a human monocytic cell line (THP-1) and mouse bone marrow-derived macrophages. In contrast to significantly decreased production of human IL-8 and TNF-? and, in mice, keratinocyte-derived cytokine (KC), macrophage inflammatory protein-2 (MIP-2), and TNF-? after repeated challenge with Escherichia coli LPS, cells repeatedly exposed to P. gingivalis LPS responded by producing less TNF-? but sustained elevated secretion of IL-8, KC, and MIP-2. Furthermore, in endotoxin-tolerant cells, production of IL-8 is controlled at the signaling level and correlates well with NF-?B activation, whereas TNF-? expression is blocked at the gene transcription level. Interferon ? plays an important role in attenuation of chemokine expression in endotoxin-tolerized cells as shown in interferon regulatory factor-3 knock-out mice. In addition, human gingival fibroblasts, commonly known not to display LPS tolerance, were found to be tolerant to repeated challenge by LPS if pretreated with interferon ?. The data suggest that the inability of the LPS-TLR2 complex to induce full endotoxin tolerance in monocytes/macrophages is related to diminished production of interferon ? and may partly explain the involvement of these LPS isoforms in the pathogenesis of chronic inflammatory diseases.

Zaric, Svetislav S.; Coulter, Wilson A.; Shelburne, Charles E.; Fulton, Catherine R.; Zaric, Marija S.; Scott, Aaron; Lappin, Mark J.; Fitzgerald, Denise C.; Irwin, Christopher R.; Taggart, Clifford C.



Altered Toll-like receptor 2-mediated endotoxin tolerance is related to diminished interferon beta production.  


Induction of endotoxin tolerance leads to a reduced inflammatory response after repeated challenge by LPS and is important for resolution of inflammation and prevention of tissue damage. Enterobacterial LPS is recognized by the TLR4 signaling complex, whereas LPS of some non-enterobacterial organisms is capable of signaling independently of TLR4 utilizing TLR2-mediated signal transduction instead. In this study we report that Porphyromonas gingivalis LPS, a TLR2 agonist, fails to induce a fully endotoxin tolerant state in a human monocytic cell line (THP-1) and mouse bone marrow-derived macrophages. In contrast to significantly decreased production of human IL-8 and TNF-? and, in mice, keratinocyte-derived cytokine (KC), macrophage inflammatory protein-2 (MIP-2), and TNF-? after repeated challenge with Escherichia coli LPS, cells repeatedly exposed to P. gingivalis LPS responded by producing less TNF-? but sustained elevated secretion of IL-8, KC, and MIP-2. Furthermore, in endotoxin-tolerant cells, production of IL-8 is controlled at the signaling level and correlates well with NF-?B activation, whereas TNF-? expression is blocked at the gene transcription level. Interferon ? plays an important role in attenuation of chemokine expression in endotoxin-tolerized cells as shown in interferon regulatory factor-3 knock-out mice. In addition, human gingival fibroblasts, commonly known not to display LPS tolerance, were found to be tolerant to repeated challenge by LPS if pretreated with interferon ?. The data suggest that the inability of the LPS-TLR2 complex to induce full endotoxin tolerance in monocytes/macrophages is related to diminished production of interferon ? and may partly explain the involvement of these LPS isoforms in the pathogenesis of chronic inflammatory diseases. PMID:21705332

Zaric, Svetislav S; Coulter, Wilson A; Shelburne, Charles E; Fulton, Catherine R; Zaric, Marija S; Scott, Aaron; Lappin, Mark J; Fitzgerald, Denise C; Irwin, Christopher R; Taggart, Clifford C



Variability in Endotoxin Exposure Levels and Consequences for Exposure Assessment  

Microsoft Academic Search

Objectives: Workers in many industries are exposed to endotoxins, which may cause adverse health effects. In exposure assessment, information about exposure variability is essential. However, variability in exposure has rarely been investigated for biological agents and more specifically for endotoxin. Therefore, variance components and determinants of exposure were studied in a large database with >2000 endotoxin measurements. Methods: Data from




House Dust Endotoxin and Allergic Sensitization in Children  

Microsoft Academic Search

A higher exposure to endotoxin was hypothesized to contribute to protective effects on atopy development by activating type-1 lower prevalence of allergic sensitization and hay fever in children T-helper cell responses on the other (9). growing up on a farm. We studied the association between house Endotoxins are more or less ubiquitous in the environment dust endotoxin and allergic sensitization.

Ulrike Gehring; Wolfgang Bischof; Barbel Fahlbusch; Heinz-Erich Wichmann; Joachim Heinrich


Effects of enteric bacterial and cyanobacterial lipopolysaccharides, and of microcystin-LR, on glutathione S-transferase activities in zebra fish ( Danio rerio)  

Microsoft Academic Search

Cyanobacteria (blue-green algae) can produce a variety of toxins including hepatotoxins e.g. microcystins, and endotoxins such as lipopolysaccharides (LPS). The combined effects of such toxins on fish are little known. This study examines the activities of microsomal (m) and soluble (s) glutathione S-transferases (GST) from embryos of the zebra fish, Danio rerio at the prim six embryo stage, which had

J. H Best; S Pflugmacher; C Wiegand; F. B Eddy; J. S Metcalf; G. A Codd



Effect of Orchidectomy on the Age-Related Modulation of IL1? and IL1 Receptors following Lipopolysaccharide Treatment in the Mouse  

Microsoft Academic Search

Objective: To compare the effect of orchidectomy (ODX) in 7- and 24-week-old C57BL\\/6 mice on the age-related responses of the cytokine interleukin (IL)-1? and its receptor to intraperitoneal injection of the bacterial endotoxin, lipopolysaccharide (LPS). Methods: We measured IL-1? concentrations in the plasma, hippocampus, hypothalamus and adrenal gland using ELISA and iodine-125-labeled recombinant human IL-1? ([125I]IL-1?) binding in the hippocampus

Wakako Nanamiya; Toshihiro Takao; Koichi Asaba; Errol B. De Souza; Kozo Hashimoto



CD14 Is Expressed and Released as Soluble CD14 by Human Intestinal Epithelial Cells In Vitro: Lipopolysaccharide Activation of Epithelial Cells Revisited  

Microsoft Academic Search

Human endothelial as well as epithelial cells were shown to respond to lipopolysaccharides (LPSs). However, the expression and release of CD14 by these so-called CD14-negative cells have not been studied in detail. We investigated three human intestinal epithelial cell lines (ECLs), SW-480, HT-29, and Caco-2, for their expres- sion of CD14 and CD11c\\/CD18 as well as their responsiveness to endotoxins.




Increased lipopolysaccharide sensitivity in alcoholic fatty livers is independent of leptin deficiency and toll-like receptor 4 (TLR4) or TLR2 mRNA expression  

Microsoft Academic Search

BACKGROUND: Both alcoholic (AFL) and nonalcoholic (NAFL) fatty livers show increased sensitivity to endotoxin-induced injury. Lipopolysaccharide (LPS) is recognized by toll-like receptor 4 (TLR4), whereas lipopeptide triggers TLR2 to induce common downstream activation of nuclear factor (NF)-kappaB and pro-inflammatory pathways that are activated in AFL and NAFL.\\u000aMETHODS: Serum alanine aminotransferase (ALT), tumor necrosis factor (TNF)-alpha, and interleukin (IL)-6 levels;

Laszlo Romics; Pranoti Mandrekar; Karen Kodys; Arumugam Velayudham; Yvonne Drechsler; Angela Dolganiuc; Gyongyi Szabo



Mammalian Nitrate Biosynthesis: Incorporation of 15NH3 into Nitrate is Enhanced by Endotoxin Treatment  

NASA Astrophysics Data System (ADS)

Incorporation of an oral dose of [15N]ammonium acetate into urinary [15N]nitrate has been demonstrated in the rat. Investigation of the regulation of nitrate synthesis has shown that Escherichia coli lipopolysaccharide potently stimulates urinary nitrate excretion (9-fold increase). It was further shown that the enhanced rate of nitrate excretion by lipopolysaccharide was due not to a reduction in nitrate metabolic loss but rather to an increased rate of synthesis. This conclusion was based on finding a proportionally increased incorporation of [15N]ammonium into nitrate nitrogen with lipopolysaccharide treatment. Nitrate biosynthesis was also increased by intraperitoneal injection of carrageenan and subcutaneous injection of turpentine. It is proposed that the pathway of nitrate biosynthesis may be the result of oxidation of reduced nitrogen compounds by oxygen radicals generated by an activated reticuloendothelial system.

Wagner, David A.; Young, Vernon R.; Tannenbaum, Steven R.



Allantoin as a solid phase adsorbent for removing endotoxins.  


In this study we present a simple and robust method for removing endotoxins from protein solutions by using crystals of the small-molecule compound 2,5-dioxo-4-imidazolidinyl urea (allantoin) as a solid phase adsorbent. Allantoin crystalline powder is added to a protein solution at supersaturated concentrations, endotoxins bind and undissolved allantoin crystals with bound endotoxins are removed by filtration or centrifugation. This method removes an average of 99.98% endotoxin for 20 test proteins. The average protein recovery is ?80%. Endotoxin binding is largely independent of pH, conductivity, reducing agent and various organic solvents. This is consistent with a hydrogen-bond based binding mechanism. Allantoin does not affect protein activity and stability, and the use of allantoin as a solid phase adsorbent provides better endotoxin removal than anion exchange, polymixin affinity and biological affinity methods for endotoxin clearance. PMID:24001944

Vagenende, Vincent; Ching, Tim-Jang; Chua, Rui-Jing; Gagnon, Pete



Endotoxin-free purification for the isolation of Bovine Viral Diarrhoea Virus E2 protein from insoluble inclusion body aggregates  

PubMed Central

Background Protein expression in Escherichia coli may result in the recombinant protein being expressed as insoluble inclusion bodies. In addition, proteins purified from E. coli contain endotoxins which need to be removed for in vivo applications. The structural protein, E2, from Bovine Viral Diarrhoea Virus (BVDV) is a major immunogenic determinant, and is an ideal candidate as a subunit vaccine. The E2 protein contains 17 cysteine residues creating difficulties in E. coli expression. In this report we outline a procedure for successfully producing soluble and endotoxin-free BVDV E2 protein from inclusion bodies (IB). Results The expression of a truncated form of BVDV-E2 protein (E2-T1) in E. coli resulted in predominantly aggregated insoluble IB. Solubilisation of E2-T1 with high purity and stability from IB aggregates was achieved using a strong reducing buffer containing 100 mM Dithiothreitol. Refolding by dialysis into 50 mM Tris (pH 7.0) containing 0.2% Igepal CA630 resulted in a soluble but aggregated protein solution. The novel application of a two-phase extraction of inclusion body preparations with Triton X-114 reduced endotoxin in solubilised E2-T1 to levels suitable for in vivo use without affecting protein yields. Dynamic light scattering analyses showed 37.5% of the protein was monomeric, the remaining comprised of soluble aggregates. Mice immunised with E2-T1 developed a high titre antibody response by ELISA. Western hybridisation analysis showed E2-T1 was recognised by sera from immunised mice and also by several BVDV-E2 polyclonal and monoclonal antibodies. Conclusion We have developed a procedure using E. coli to produce soluble E2-T1 protein from IB, and due to their insoluble nature we utilised a novel approach using Triton X-114 to efficiently remove endotoxin. The resultant protein is immunogenic and detectable by BVDV-E2 specific antibodies indicating its usefulness for diagnostic applications and as a subunit vaccine. The optimised E. coli expression system for E2-T1 combined with methodologies for solubilisation, refolding and integrated endotoxin removal presented in this study should prove useful for other vaccine applications.



Ambient endotoxin concentrations in PM10 from Southern California.  

PubMed Central

Concentrations of endotoxin in urban air pollution have not previously been extensively characterized. We measured 24-hr levels of PM10 (particulate matter < 10 microm in aerodynamic diameter) and the associated endotoxin component once every 6 weeks for 1 year in 13 communities in Southern California. All the samples collected had detectable PM10 and endotoxin levels. The geometric mean PM10 was 34.6 microg/m3 [geometric SD (GSD), 2.1; range, 3.0-135]. By volume, the endotoxin geometric mean was 0.44 endotoxin units (EU)/m3 (GSD, 3.1; range, 0.03-5.44). Per unit material collected, the geometric mean of endotoxin collected was 13.6 EU/mg (GSD, 3.2; range, 0.7-96.8). No correlation was found between endotoxin concentrations and other ambient pollutants concurrently measured [ozone, nitrogen dioxide, total acids, or PM2.5 (particulate matter < 2.5 micro m in aerodynamic diameter]. PM10 and endotoxin concentrations were significantly correlated, most strongly in summer. Samples collected in more rural and agricultural areas had lower PM10 and mid-range endotoxin levels. The high desert and mountain communities had lower PM10 levels but endotoxin levels comparable with or higher than the rural agricultural sites. By volume, endotoxin levels were highest at sites downwind of Los Angeles, California, which were also the locations of highest PM10. Endotoxin concentrations measured in this study were all < 5.5 EU/m3, which is lower than recognized thresholds for acute adverse health effects for occupational exposures but in the same range as indoor household concentrations. This study provides the first extensive characterization of endotoxin concentration across a large metropolitan area in relation to PM10 and other pollutant monitoring, and supports the need for studies of the role of endotoxin in childhood asthma in urban settings.

Mueller-Anneling, Linda; Avol, Ed; Peters, John M; Thorne, Peter S



Associated Leukocyte Responses in the Lethal Aspects of 'E. Coli' Shock.  

National Technical Information Service (NTIS)

The purpose of the present study was to explore the responses of canine blood to the separate effects of E. coli organisms and E. coli endotoxin, particularly emphasizing the role of the WBC in the uptake of glucose in vitro and its possible relationship ...

L. B. Hinshaw B. K. Beller L. T. Archer G. L. White



Genome-Wide Expression Analysis of Lipopolysaccharide-Induced Mastitis in a Mouse Model  

Microsoft Academic Search

To better understand the acute host response to Escherichia coli mastitis, we analyzed gene expression patterns of approximately 23,000 transcripts 4 h after an intramammary infusion of lipopolysaccharide (LPS) in a mouse model. A total of 489 genes were significantly affected, of which 391 were induced and 98 were repressed. Gene ontology analysis demonstrated that most of the induced genes

Jiamao Zheng; Anjanette D. Watson; David E. Kerr



Lipopolysaccharide interaction with hemolin, an insect member of the Ig-superfamily  

Microsoft Academic Search

This study is an attempt to reach some understanding of how insects recognize intruding microorganisms and foreign entities while executing an immune response. We used lipopolysaccharide (LPS) from Escherichia coli, bound to a radiolabeled iodinated crosslinker, to identify hemolymph proteins from the Hyalophora cecropia moth that have the capacity to bind LPS. High amounts of radioactivity were conferred to hemolin,

Sirlei Daffre; Ingrid Faye



Adipokinetic hormone enhances nodule formation and phenoloxidase activation in adult locusts injected with bacterial lipopolysaccharide  

Microsoft Academic Search

Interactions between the locust endocrine and immune systems have been studied in vivo in relation to nodule formation and activation of the prophenoloxidase cascade in the haemolymph. Injection of bacterial lipopolysaccharide (LPS) extracted from Escherichia coli induces nodule formation in larval and adult locusts but does not increase phenoloxidase activity in the haemolymph. Nodule formation starts rapidly after injection of

Graham Goldsworthy; Shashi Chandrakant; Kwaku Opoku-Ware




Technology Transfer Automated Retrieval System (TEKTRAN)

Four multiparous lactating cows [175-220 days in milk (DIM)] were used in a 4x4 Latin square design to assess the effects of increasing doses [0.0, 0.5, 10, 1.5 ug/kg body weight (BW)] of lipopolysaccharide (LPS; Escherichia coli 0lll:B4) on performance and plasma metabolite and hormone concentratio...


A static magnetic field attenuates lipopolysaccharide-induced neuro-inflammatory response via IL-6-mediated pathway.  


Abstract An effective method for controlling brain damage and neurodegeneration caused by inflammation remains elusive. Down-expression of the lipopolysaccharide (LPS)-induced inflammatory cytokines resulting in endotoxin tolerance is reported as an alternative anti-infection treatment. Nonetheless, because the dosage and action site are hard to control, endotoxin tolerance caused by low-dose LPS injection in brain tissue may induce side effects. The aim of this study was to test the hypothesis that static magnetic fields (SMF) stimulate endotoxin tolerance in brain tissue. In this study, survival rate and pathological changes in brain tissues of LPS-challenged mice were examined with and without SMF treatment. In addition, the effects of SMF exposure on growth rate and cytokine expression of LPS-challenged BV-2 microglia cells were monitored. Our results showed that SMF pre-exposure had positive effects on the survival rate and histological outcomes of LPS-treated mice. Furthermore, SMF exposure significantly decreased IL-6 expression in BV-2 cells (p?endotoxin tolerance. We suggest that SMF has potential as an alternative simulation source for controlling LPS-induced excess neuro-inflammatory response. PMID:23781996

Shen, Li-Kuo; Huang, Haw-Ming; Yang, Po-Chieh; Huang, Yung-Kai; Wang, Peter Da-Yun; Leung, Ting-Kai; Chen, Chi-Jen; Chang, Wei-Jen



Differences in organ dysfunction in endotoxin-tolerant pigs under intensive care exposed to a second hit of endotoxin.  


Endotoxin tolerance is a well-studied phenomenon associated with a reduced inflammatory response. In the switch from an inflammatory to an anti-inflammatory response in clinical sepsis, the concept of endotoxin tolerance is of obvious interest. However, only limited data exist regarding the effect of endotoxin tolerance on organ dysfunction, and therefore, this was investigated in a porcine intensive care sepsis model. Twenty-seven healthy pigs, including nine control animals, were included in the study. Twelve pigs pre-exposed to 24 h of intravenous endotoxin infusion and intensive care and six unexposed pigs were given either a high- or low-dose endotoxin challenge for 6 h. Inflammatory, circulatory, hypoperfusion, and organ dysfunction parameters were followed. The inflammatory responses as well as parameters representing circulation, hypoperfusion, and cardiac and renal function were all markedly attenuated in animals pre-exposed to endotoxin and intensive care as compared with animals not pre-exposed. In animals pre-exposed to endotoxin and given the high-dose of endotoxin challenge, deterioration in pulmonary function was equal to or even worse than in animals not pre-exposed. In contrast to the overall protective effect of endotoxin tolerance observed in other organ systems, the lungs of endotoxin-tolerant animals demonstrated an increased responsiveness to high-dose endotoxin challenge. PMID:22266970

Castegren, Markus; Lipcsey, Miklós; Söderberg, Ewa; Skorup, Paul; Eriksson, Mats; Larsson, Anders; Sjölin, Jan



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


Stimulation of Cells Derived from Nifedipine-induced Gingival Overgrowth with Porphyromonas gingivalis, Lipopolysaccharide, and Interleukin1?  

Microsoft Academic Search

The purpose of this study was to clarify the main contributory factor of nifedipine-induced gingival overgrowth either by Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) or interleukin-1beta (IL-1?). Human gingival fibroblasts from healthy tissues and nifedipine-induced gingival overgrowth tissues were stimulated with nifedipine, IL-1?, Escherichia coli lipopolysaccharide (Ec-LPS), and Pg-LPS, and the gene expressions were analyzed by RT-PCR. Analysis of the data showed

H.-K. Lu; H.-P. Chou; C.-L. Li; M.-Y. Wang; L.-F. Wang



Solution NMR studies provide structural basis for endotoxin pattern recognition by the innate immune receptor CD14  

SciTech Connect

CD14 functions as a key pattern recognition receptor for a diverse array of Gram-negative and Gram-positive cell-wall components in the host innate immune response by binding to pathogen-associated molecular patterns (PAMPs) at partially overlapping binding site(s). To determine the potential contribution of CD14 residues in this pattern recognition, we have examined using solution NMR spectroscopy, the binding of three different endotoxin ligands, lipopolysaccharide, lipoteichoic acid, and a PGN-derived compound, muramyl dipeptide to a {sup 15}N isotopically labeled 152-residue N-terminal fragment of sCD14 expressed in Pichia pastoris. Mapping of NMR spectral changes upon addition of ligands revealed that the pattern of residues affected by binding of each ligand is partially similar and partially different. This first direct structural observation of the ability of specific residue combinations of CD14 to differentially affect endotoxin binding may help explain the broad specificity of CD14 in ligand recognition and provide a structural basis for pattern recognition. Another interesting finding from the observed spectral changes is that the mode of binding may be dynamically modulated and could provide a mechanism for binding endotoxins with structural diversity through a common binding site.

Albright, Seth; Chen Bin; Holbrook, Kristen [Biochemistry, Cellular and Molecular Biology Department, University of Tennessee, M407 Walters Life Sciences, 1410 Cumberland Avenue, Knoxville, TN 37996-0840 (United States); Jain, Nitin U. [Biochemistry, Cellular and Molecular Biology Department, University of Tennessee, M407 Walters Life Sciences, 1410 Cumberland Avenue, Knoxville, TN 37996-0840 (United States)], E-mail:



TLR4 activation of TRPC6-dependent calcium signaling mediates endotoxin-induced lung vascular permeability and inflammation  

PubMed Central

Lung vascular endothelial barrier disruption and the accompanying inflammation are primary pathogenic features of acute lung injury (ALI); however, the basis for the development of both remains unclear. Studies have shown that activation of transient receptor potential canonical (TRPC) channels induces Ca2+ entry, which is essential for increased endothelial permeability. Here, we addressed the role of Toll-like receptor 4 (TLR4) intersection with TRPC6-dependent Ca2+ signaling in endothelial cells (ECs) in mediating lung vascular leakage and inflammation. We find that the endotoxin (lipopolysaccharide; LPS) induces Ca2+ entry in ECs in a TLR4-dependent manner. Moreover, deletion of TRPC6 renders mice resistant to endotoxin-induced barrier dysfunction and inflammation, and protects against sepsis-induced lethality. TRPC6 induces Ca2+ entry in ECs, which is secondary to the generation of diacylglycerol (DAG) induced by LPS. Ca2+ entry mediated by TRPC6, in turn, activates the nonmuscle myosin light chain kinase (MYLK), which not only increases lung vascular permeability but also serves as a scaffold to promote the interaction of myeloid differentiation factor 88 and IL-1R–associated kinase 4, which are required for NF-?B activation and lung inflammation. Our findings suggest that TRPC6-dependent Ca2+ entry into ECs, secondary to TLR4-induced DAG generation, participates in mediating both lung vascular barrier disruption and inflammation induced by endotoxin.

Tauseef, Mohammad; Knezevic, Nebojsa; Chava, Koteswara R.; Smith, Monica; Sukriti, Sukriti; Gianaris, Nicholas; Obukhov, Alexander G.; Vogel, Stephen M.; Schraufnagel, Dean E.; Dietrich, Alexander; Birnbaumer, Lutz; Malik, Asrar B.



Single-trial conditioning in a human taste-endotoxin paradigm induces conditioned odor aversion but not cytokine responses.  


Immunological responses to bacterial endotoxin can be behaviorally conditioned in rodents. However, it is unclear whether an acute systemic inflammatory response can be behaviorally conditioned in humans. Thus, in a double-blind placebo-controlled study, 20 healthy, male subjects received either a single injection of lipopolysaccharide (LPS) or saline together with a novel tasting beverage (conditioned stimulus, CS). Five days later, all subjects received a saline injection and were re-exposed to the CS. Blood was drawn prior to as well as 0.5, 1.5, 3, 4, 6, and 24 h after LPS administration or CS re-exposure. Endotoxin administration led to transient increases in plasma concentrations of interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-? and to a significant rise in body temperature. Sole presentation of the CS during evocation did induce neither alterations in body temperature nor changes in plasma cytokine levels. However, subjects in the experimental group rated the smell of the CS significantly more aversive compared to the control group. Employing endotoxin as a US in a single trial taste-immune conditioning paradigm in humans shows a behaviorally conditioned smell aversion but no learned alterations in cytokine levels. PMID:21925260

Grigoleit, Jan-Sebastian; Kullmann, Jennifer S; Winkelhaus, Anne; Engler, Harald; Wegner, Alexander; Hammes, Florian; Oberbeck, Reiner; Schedlowski, Manfred



NF-?B-mediated degradation of the coactivator RIP140 regulates inflammatory responses and contributes to endotoxin tolerance.  


Tolerance to endotoxins that is triggered by prior exposure to Toll-like receptor (TLR) ligands provides a mechanism with which to dampen inflammatory cytokines. The receptor-interacting protein RIP140 interacts with the transcription factor NF-?B to regulate the expression of genes encoding proinflammatory cytokines. Here we found lipopolysaccharide stimulation of kinase Syk-mediated tyrosine phosphorylation of RIP140 and interaction of the NF-?B subunit RelA with RIP140. These events resulted in more recruitment of the E3 ligase SCF to tyrosine-phosphorylated RIP140, which degraded RIP140 to inactivate genes encoding inflammatory cytokines. Macrophages expressing nondegradable RIP140 were resistant to the establishment of endotoxin tolerance for specific 'tolerizable' genes. Our results identify RelA as an adaptor with which SCF fine tunes NF-?B target genes by targeting the coactivator RIP140 and show an unexpected role for RIP140 degradation in resolving inflammation and endotoxin tolerance. PMID:22388040

Ho, Ping-Chih; Tsui, Yao-Chen; Feng, Xudong; Greaves, David R; Wei, Li-Na



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...


Comparison of the action of prostaglandin with endotoxin on thermoregulatory response thresholds  

Microsoft Academic Search

Prostaglandin E2 (PGE2) and lipopolysaccharide (LPS) derived fromE. coli were injected into the lateral cerebral ventricle of rabbits at 30° C ambient temperature. The threshold core temperatures for ear cutaneous vasoconstriction. (Thv) and shivering (Thsh) were determined by whole-body cooling with an intestinal thermode. Each threshold, as determined at the plateau phase of LPS fever and PGE2 hyperthermia respectively, were

Masaaki Hashimoto; Masanori Nagai; Masami Iriki



Prolonged elevation in hippocampal A? and cognitive deficits following repeated endotoxin exposure in the mouse.  


Alzheimer's disease (AD) is characterized by neuronal cell death and atrophy in regions of the adult brain, including the hippocampus and cortex, due to formation of amyloid beta (A?) plaques and neurofibrillary tangles. The presence of these pathologies can limit normal signaling properties and ultimately lead to learning and memory deficits. Chronic inflammation has been implicated in the onset and progression of these AD-related pathologies. Our study was designed to assess the effects of peripheral inflammation on pathologies associated with AD by using the bacterial endotoxin lipopolysaccharide (LPS). C57BL/6J mice were given intraperitoneal injections of LPS or saline for 1, 3, or 7 consecutive days. Hippocampal tissue from animals receiving LPS contained significantly higher levels of A?1-42, a peptide component of AD plaques, than did those from saline control animals. Central and peripheral pro-inflammatory cytokine levels were increased following a single injection of LPS, but retuned to baseline levels before cognitive testing began. We show that one injection of LPS leads to sickness behavior, but 7 consecutive days does not, indicating tolerance to the endotoxin. Cognitive testing was then conducted to determine if whether deficits from increased A?1-42 was evident. Results from both Morris water maze and contextual fear conditioning revealed cognitive deficits in LPS-treated mice. In summary, multiple injections of LPS resulted in increased A?1-42 in the hippocampus and cognitive deficits in mice. PMID:22249135

Kahn, Marielle S; Kranjac, Dinko; Alonzo, Chris A; Haase, Jennifer H; Cedillos, Rudy O; McLinden, Kristina A; Boehm, Gary W; Chumley, Michael J



Effects of IFN-alpha on the inflammatory response of swine leukocytes to bacterial endotoxin.  


Because low-dose interferon-alpha (IFN-alpha) treatment had proved effective in several models of chronic inflammation and autoimmune disease, a possible role of IFN-alpha in modulating the response of swine leukocytes to bacterial endotoxin was investigated in this study. Exposure of swine peripheral blood mononuclear cells (PBMC) to low concentrations of human IFN-alpha caused a strong, dose-dependent decrease in CD14 expression, the lowest level being observed at 5 U/ml IFN-alpha. This result was confirmed if PBMC were later exposed to purified lipopolysaccharide (LPS). A 10-fold lower IFN-alpha concentration (0.5 U/ml) caused the largest reduction of tumor necrosis factor-alpha (TNF-alpha) accumulation in the medium of pulmonary alveolar macrophages (PAM), stimulated with bacterial LPS. At 0.5 U/ml, the expression of the TNF-alpha gene in PAM was also strongly reduced, as opposed to cells pretreated with 50 U/ml IFN-alpha. In contrast, expression of the interleukin-1beta (IL- 1beta) gene was stimulated and that of the IL-6 gene was not significantly affected at both IFN-alpha concentrations. Results point to an important role of IFN-alpha in control of the inflammatory response to bacterial endotoxin in pigs. PMID:15812246

Begni, Barbara; Amadori, Massimo; Ritelli, Marco; Podavini, Damiano



Isolation, characterization, and biological properties of an endotoxin-like material from the gram-positive organism Listeria monocytogenes.  

PubMed Central

The bacterial component responsible for the induction of transient cold agglutinin syndrome in rabbits after intravenous injection of heat-killed Listeria monocytogenes type 4B has been purified and biologically and chemically characterized. A purified immunoglobulin M cold agglutinin was prepared from high-titer sera resulting from the immunization of rabbits with heat-killed L. monocytogenes type 4B and was subsequently used to monitor the purification of the bacterial component responsible for its induction. The bacterial component was isolated from a hot phenol-water extract of lyophilized L. monocytogenes type 4B by multiple molecular sieve chromatography. Upon chemical analysis the purified material was found to be strikingly similar in chemical composition to gram-negative lipopolysaccharide endotoxins. The material contained 15% total fatty acid (of which 50% was beta-hydroxymyristic acid), 40 to 45% neutral sugar (glucose, galactose, and rhamnose), 11.5% amino sugar, 12% uronic acid, 2.5% 2-keto-3-deoxyoctonic acid, 2% heptose, 0.87% phosphorus, and 1.6% amino acid, thereby accounting for 85 to 90% of the weight of the component. Electron micrographs of the purified material were similar to those of lipopolysaccharide preparations from gram-negative organisms. The purified material exist in aqueous solutions as large aggregates, but can be dissociated into a single smaller subunit (3.1S) by dialysis against sodium dodecyl sulfate buffer. The listerial component was toxic and pyrogenic to rabbits, producing symptoms typical of gram-negative endotoxins. Activity in the limulus lysate gelation assay and in the carbocyanine dye assay provides a further link of this material with classical gram-negative endotoxins. Images

Wexler, H; Oppenheim, J D



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



Endotoxin-induced effects on nucleotide catabolism in mouse kidney.  


Extracellular adenosine 5'-triphosphate (ATP) acts as a proinflammatory mediator. Adenosine, the final product of ATP breakdown, is an anti-inflammatory compound, acting mainly on adenosine A(2A) receptors. Considering that the kidney is an organ strongly affected during systemic inflammatory responses and that ectonucleotidases are responsible for the control of extracellular nucleotide and nucleoside levels, we examined the endotoxin-induced effects on ectonucleotidases in kidney membranes of mice, and whether CGS-21680 hydrochloride (3-[4-[2-[[6-amino-9-[(2R,3R,4S,5S)-5-(ethylcarbamoyl)-3,4-dihydroxy-oxolan-2-yl]purin-2-yl]amino]ethyl]phenyl]propanoic acid), a selective adenosine A(2A) receptor agonist, antagonizes the lipopolysaccharide (LPS)-induced effects on nucleotide catabolism in kidney. Animals were injected intraperitoneally with 12 mg/kg LPS and/or 0.5mg/kg CGS-21680 or saline. Nucleotidase activities were determined in kidney membrane preparations and ATP metabolism was measured by high performance liquid chromatography (HPLC) assay. Analysis of ectonucleotidase expression was carried out by semi-quantitative semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Exposure to endotoxemia promoted an increase in ATP and p-Nitrophenyl thymidine 5'-monophosphate (p-Nph-5'-TMP) hydrolysis, and a decrease in adenosine 5'-monophosphate (AMP) hydrolysis. CGS-21680 treatment failed to reverse these changes. HPLC analysis indicated a decrease in extracellular ATP and adenosine levels in groups treated with LPS and LPS plus CGS-21680. The expression pattern of ectonucleotidases revealed an increase in Entpd3, Enpp2, and Enpp3 mRNA levels after LPS injection. These findings indicate that nucleotide and nucleoside availability in mouse kidney is altered at different stages of endotoxemia, in order to protect the integrity of this organ when exposed to systemic inflammation. PMID:22108548

Vuaden, Fernanda C; Savio, Luiz Eduardo B; Ramos, Denise B; Casali, Emerson A; Bogo, Maurício R; Bonan, Carla D



Role for circulating lipoproteins in protection from endotoxin toxicity.  

PubMed Central

Previous studies have shown that endotoxin (lipopolysaccharide [LPS])-induced death can be prevented by preincubating LPS with lipoproteins in vitro or by infusing large quantities of lipids into animals prior to LPS administration. In the present study we determined whether physiological levels of lipids also provide protection. Serum lipid levels were decreased by two different mechanisms: administration of 4-aminopyrolo-(3,4-D)pyrimide, which prevents the hepatic secretion of lipoproteins, and administration of pharmacological doses of estradiol, which increases the number of hepatic low-density lipoprotein receptors, leading to increased lipoprotein clearance. In both hypolipidemic models, LPS-induced mortality is markedly increased compared with that of controls with normal serum lipid levels. In both hypolipidemic models, administration of exogenous lipoproteins, which increase levels of serum lipids into the physiological range, reduces the increased mortality to levels similar to that seen in normal animals. In normal lipidemic animals, 63% of 125I-LPS in plasma is associated with lipoproteins, where it would not be capable of stimulating cytokine production. In contrast, in hypolipidemic animals, very little LPS (12 to 17%) is associated with lipoproteins. Rather, more LPS is in the lipoprotein-free plasma compartment, where it could exert biological effects. In both hypolipidemic models, LPS produces a greater increase in serum tumor necrosis factor levels than it does in controls (three- to fivefold increase), and administration of exogenous lipoproteins prevents this increase. Cytokines, in particular tumor necrosis factor, are responsible for most of the toxic effects of LPS. These data provide evidence that physiological levels of serum lipids protect animals from LPS toxicity. Thus, lipoproteins, in addition to playing a role in lipid transport, may have protective functions. Moreover, as part of the immune response, cytokine-induced increases in serum lipid levels may play a role in host defense by decreasing the toxicities of biological and chemical agents.

Feingold, K R; Funk, J L; Moser, A H; Shigenaga, J K; Rapp, J H; Grunfeld, C



40 CFR 180.1107 - Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas...  

Code of Federal Regulations, 2011 CFR

...2013-07-01 false Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated...Tolerances § 180.1107 Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated...tolerance. The delta endotoxin of Bacillus thuringiensis variety kurstaki...



Effect of vasopressors on organ blood flow during endotoxin shock in pigs  

SciTech Connect

A volume-resuscitated porcine endotoxin shock model was used to evaluate the effect on organ blood flow of increasing systemic arterial blood pressure with vasopressors. Administration of 0.05-0.2 mg/kg of Escherichia coli endotoxin (E) reduced mean arterial blood pressure (MAP) to 50 mmHg, decreased systemic vascular resistance to 50% of control, and did not change cardiac output or heart rate. Blood flow measured with radiolabeled microspheres to brain, kidney, spleen, and skeletal muscle was reduced during endotoxin shock, but blood flow to left ventricle, small and large intestine, and stomach remained at pre-endotoxin levels throughout the study period. Four groups of animals were used to evaluate the effect of vasopressor therapy. Vasopressors were administered starting 60 min after E exposure, and the dose of each was titrated to increase MAP to 75 mmHg. Despite the increase in MAP, brain blood flow did not increase in any group. Norepinephrine alone increased blood flow to the left ventricle. The dose of norepinephrine required to increase MAP by 20-25 mmHg during E shock was 30 times the does required for a similar increase in MAP in animals not receiving E. The authors conclude 1) that hypotension in the fluid resuscitated porcine E shock model is primarily the result of peripheral vasodilatation, 2) that the vascular response to vasoconstrictors in this model is markedly attenuated following E administration, 3) that blood pressure elevation with norepinephrine, dopamine, and phenylephrine neither decreases blood flow to any organs nor increases blood flow to organs with reduced flow, and 4) that norepinephrine, dopamine, and phenylephrine affect regional blood flow similarly in this model.

Breslow, M.J.; Miller, C.F.; Parker, S.D.; Walman, A.T.; Traystman, R.J.



Adsorption of endotoxin from aqueous solution using bone char.  


The aim of this study is the removal of endotoxin from aqueous solution using bone char (BC) as an adsorbent material. The BC was prepared from cattle animal bone by pyrolysis in a furnace at 850 degrees C. The morphology and physico-chemical characteristics of the adsorbent were investigated. Kinetic studies revealed that the adsorption of endotoxin is rapid. The adsorption mechanisms in the endotoxin-BC had a significant contribution from film diffusion. The maximum adsorption efficiency achieved is 98% at an adsorbent dose of 40 g L(-1) with an initial endotoxin concentration of 80 Eu mL(-1). The results show that the Langmuir isotherm adsorption equation model describe the experimental adsorption isotherm with good accuracy. A survey of the regeneration capabilities showed that the BC could be regenerated and rendered endotoxin free by heating at 350 degrees C for 30 min. The results suggest that BC could be used as effective adsorbent for endotoxin removal. PMID:19280089

Rezaee, A; Ghanizadeh, Gh; Behzadiyannejad, Gh; Yazdanbakhsh, A; Siyadat, S D



P-selectin and ICAM-1 mediate endotoxin-induced neutrophil recruitment and injury to the lung and liver.  


The role of leukocyte adhesion molecules in endotoxin-induced organ injury was evaluated by administering intraperitoneal Salmonella enteritidis lipopolysaccharide (LPS) to wild-type (WT) mice, P-selectin-deficient mice, intercellular adhesion molecule (ICAM)-1-deficient mice, and P-selectin-ICAM-1 double-mutant mice. In WT mice, there was a sevenfold increase in the number of neutrophils present in the pulmonary vascular lavage fluid, and there were sevenfold more intracapillary neutrophils by electron-microscopic (EM) morphometry at 4 h after intraperitoneal LPS compared with that in control mice. Extravascular albumin accumulation increased approximately twofold in the lungs and liver of WT mice treated with LPS. In the double-mutant mice, although overall mortality after intraperitoneal LPS was not attenuated, there was a significant delay in mortality in the P-selectin-ICAM-1-deficient mutants compared with that in WT mice after intraperitoneal LPS (P < 0.01). Moreover, compared with LPS-treated WT mice, lung and liver extravascular albumin accumulation was significantly lower in LPS-treated P-selectin-ICAM-1 double-mutant mice. Lung myeloperoxidase activity, normalized per 1,000 circulating neutrophils, increased after endotoxin in WT and P-selectin-deficient mice but not in P-selectin-ICAM-1 double-mutant mice. In addition, lung and liver myeloperoxidase activity per 1,000 circulating neutrophils in endotoxin-treated ICAM-1-deficient mice and P-selectin-ICAM-1 double mutants was significantly lower compared with that in endotoxin-treated WT mice. These data suggest that P-selectin and ICAM-1 significantly contribute to lung and liver injury after systemic endotoxemia. PMID:10444525

Kamochi, M; Kamochi, F; Kim, Y B; Sawh, S; Sanders, J M; Sarembock, I; Green, S; Young, J S; Ley, K; Fu, S M; Rose, C E



Regulation of adolescent rat intestinal epithelial inducible nitric oxide synthase expression in endotoxin tolerance: modulation of signal transduction.  


Endotoxin/lipopolysaccharide (LPS) tolerance is a state of induced hyporesponsiveness to endotoxin or LPS characterized by alterations in the release of inflammatory mediators. As the gut is both a source of infection and target of injury, we tested the hypothesis that alterations in intestinal epithelial signal transduction would account for the acquisition of endotoxin tolerance as defined by decreased induction of a key mediator of gut injury, inducible nitric oxide synthase (iNOS). Rats (15 days of age) were injected with saline or LPS (1 microg/g i.p.). Tissue was harvested after 1, 4, or 6 h for assessment of signaling and iNOS expression. Other animals received a second dose of LPS 1 to 7 days after the initial dose. Selected animals received the p38 inhibitor, SB203580 (10 microg/g), which was co-administered with the first dose of LPS. Induction of iNOS mRNA and protein was significantly attenuated after repeated LPS administration. Epithelial cells from LPS-tolerant rats showed a minimal level of iNOS expression by immunohistochemistry. The down-regulation of intestinal iNOS was not gender dependent. p38 inhibition enhanced tolerance rather than blocking it. LPS-mediated activation of NF-kappaB was attenuated in a manner consistent with a primary role in the induction of tolerance. Endotoxin tolerance can be demonstrated in intestinal epithelial cells using an in vivo model. Modulation of NF-kappaB signaling may be key in the down-regulation of LPS effect seen in tolerance. PMID:15087826

Cerezo, Caroline S; Kulpa-Oliver, Vyta; Gruppuso, Philip A; Morin, Melinda J



Predictors of airborne endotoxin concentrations in inner city homes.  


Few studies have assessed in home factors which contribute to airborne endotoxin concentrations. In 85 inner city Baltimore homes, we found no significant correlation between settled dust and airborne endotoxin concentrations. Certain household activities and characteristics, including frequency of dusting, air conditioner use and type of flooring, explained 36-42% of the variability of airborne concentrations. Measurements of both airborne and settled dust endotoxin concentrations may be needed to fully characterize domestic exposure in epidemiologic investigations. PMID:21429483

Mazique, D; Diette, G B; Breysse, P N; Matsui, E C; McCormack, M C; Curtin-Brosnan, J; Williams, D L; Peng, R D; Hansel, N N



Predictors of Endotoxin Levels in U.S. Housing  

PubMed Central

Background The relationship of domestic endotoxin exposure to allergy and asthma has been widely investigated. However, few studies have evaluated predictors of household endotoxin, and none have done so for multiple locations within homes and on a national scale. Objectives We assayed 2,552 house dust samples in a nationwide study to understand the predictors of household endotoxin in bedroom floors, family room floors, beds, kitchen floors, and family room sofas. Methods Reservoir house dust from five locations within homes was assayed for endotoxin and demographic and housing information was assessed through questionnaire and onsite evaluation of 2,456 residents of 831 homes selected to represent national demographics. We performed repeated-measures analysis of variance (rANOVA) for 37 candidate variables to identify independent predictors of endotoxin. Meteorologic data were obtained for each primary sampling unit and tested as predictors of indoor endotoxin to determine if wetter or warmer microclimates were associated with higher endotoxin levels. Results Weighted geometric mean endotoxin concentration ranged from 18.7 to 80.5 endotoxin units (EU)/mg for the five sampling locations, and endotoxin load ranged from 4,160 to 19,500 EU/m2. Bivariate analyses and rANOVA demonstrated that major predictors of endotoxin concentration were sampling location in the home, census division, educational attainment, presence of children, current dog ownership, resident-described problems with cockroaches, food debris, cockroach stains, and evidence of smoking observed by field staff. Low household income entered the model if educational attainment was removed. Conclusion Increased endotoxin in household reservoir dust is principally associated with poverty, people, pets, household cleanliness, and geography.

Thorne, Peter S.; Cohn, Richard D.; Mav, Deepak; Arbes, Samuel J.; Zeldin, Darryl C.




Microsoft Academic Search

AGI-30 impingers and the PGP dust-sampling system were used to collect airborne endotoxin in animal houses. Both sampling methods correlated well with each other (r2=0.75). The collection efficiency of the impinger was higher than the efficiency of the PGP dust-sampling system, especially in animal houses with high concentrations of airborne endotoxin. The use of AGI-30 impingers for sampling airborne endotoxin

B.-A. Zucker; A. M. Draz; W. Müller



[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



Biosynthesis of the Polymannose Lipopolysaccharide O-antigens from Escherichia coli Serotypes O8 and O9a Requires a Unique Combination of Single- and Multiple-active Site Mannosyltransferases*  

PubMed Central

The Escherichia coli O9a and O8 O-antigen serotypes represent model systems for the ABC transporter-dependent synthesis of bacterial polysaccharides. The O9a and O8 antigens are linear mannose homopolymers containing conserved reducing termini (the primer-adaptor), a serotype-specific repeat unit domain, and a terminator. Synthesis of these glycans occurs on the polyisoprenoid lipid-linked primer, undecaprenol pyrophosphoryl-GlcpNAc, by two conserved mannosyltransferases, WbdC and WbdB, and a serotype-specific mannosyltransferase, WbdA. The glycan structure and pattern of conservation in the O9a and O8 mannosyltransferases are not consistent with the existing model of O9a biosynthesis. Here we establish a revised pathway using a combination of in vivo (mutant complementation) experiments and in vitro strategies with purified enzymes and synthetic acceptors. WbdC and WbdB synthesize the adaptor region, where they transfer one and two ?-(1?3)-linked mannose residues, respectively. The WbdA enzymes are solely responsible for forming the repeat unit domains of these O-antigens. WbdAO9a has two predicted active sites and polymerizes a tetrasaccharide repeat unit containing two ?-(1?3)- and two ?-(1?2)-linked mannopyranose residues. In contrast, WbdAO8 polymerizes trisaccharide repeat units containing single ?-(1?3)-, ?-(1?2)-, and ?-(1?2)-mannopyranoses. These studies illustrate assembly systems exploiting several mannosyltransferases with flexible active sites, arranged in single- and multiple-domain formats.

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



Effect of hypertriglyceridemia on endotoxin responsiveness in humans.  

PubMed Central

Triglyceride-rich lipoproteins can inhibit endotoxin activity in vitro and in rodents. We sought to determine whether Intralipid, a triglyceride-rich fat emulsion which in contact with plasma functions similarly to endogenous lipoproteins, can alter the human response to endotoxin. Intralipid inhibited endotoxin-induced cytokine production in human whole blood in vitro in a dose-dependent manner, with maximal inhibition (up to 70%) being achieved at a concentration of 10 g/liter. In healthy men, a bolus intravenous injection of endotoxin (lot EC-5; 20 U/kg of body weight) was given midway through a 4-h infusion (125 ml/h) of either 5% glucose (n = 5) or 20% Intralipid (n = 5). The infusion of Intralipid led to an increase in triglyceride levels in serum from 95 +/- 16 to 818 +/- 135 mg/dl prior to endotoxin administration, i.e., levels that importantly reduced cytokine production in endotoxin-stimulated whole blood. However, in vivo hypertriglyceridemia did not influence inflammatory responses to endotoxin (fever, release of tumor necrosis factor and soluble tumor necrosis factor receptors, and leukocytosis) or even potentiated endotoxin responses (release of interleukins 6 and 8 and neutrophil degranulation). Hypertriglyceridemia does not inhibit the in vivo responses to endotoxin in humans.

van der Poll, T; Braxton, C C; Coyle, S M; Boermeester, M A; Wang, J C; Jansen, P M; Montegut, W J; Calvano, S E; Hack, C E; Lowry, S F



Infusion of freshly isolated autologous bone marrow derived mononuclear cells prevents endotoxin-induced lung injury in an ex-vivo perfused swine model  

PubMed Central

Introduction The acute respiratory distress syndrome (ARDS), affects up to 150,000 patients per year in the United States. We and other groups have demonstrated that bone marrow derived mesenchymal stromal stem cells prevent ARDS induced by systemic and local administration of endotoxin (lipopolysaccharide (LPS)) in mice. Methods A study was undertaken to determine the effects of the diverse populations of bone marrow derived cells on the pathophysiology of ARDS, using a unique ex-vivo swine preparation, in which only the ventilated lung and the liver are perfused with autologous blood. Six experimental groups were designated as: 1) endotoxin alone, 2) endotoxin + total fresh whole bone marrow nuclear cells (BMC), 3) endotoxin + non-hematopoietic bone marrow cells (CD45 neg), 4) endotoxin + hematopoietic bone marrow cells (CD45 positive), 5) endotoxin + buffy coat and 6) endotoxin + in vitro expanded swine CD45 negative adherent allogeneic bone marrow cells (cultured CD45neg). We measured at different levels the biological consequences of the infusion of the different subsets of cells. The measured parameters were: pulmonary vascular resistance (PVR), gas exchange (PO2), lung edema (lung wet/dry weight), gene expression and serum concentrations of the pro-inflammatory cytokines IL-1?, TNF-? and IL-6. Results Infusion of freshly purified autologous total BMCs, as well as non-hematopoietic CD45(-) bone marrow cells significantly reduced endotoxin-induced pulmonary hypertension and hypoxemia and reduced the lung edema. Also, in the groups that received BMCs and cultured CD45neg we observed a decrease in the levels of IL-1? and TNF-? in plasma. Infusion of hematopoietic CD45(+) bone marrow cells or peripheral blood buffy coat cells did not protect against LPS-induced lung injury. Conclusions We conclude that infusion of freshly isolated autologous whole bone marrow cells and the subset of non-hematopoietic cells can suppress the acute humoral and physiologic responses induced by endotoxemia by modulating the inflammatory response, mechanisms that do not involve engraftment or trans-differentiation of the cells. These observations may have important implications for the design of future cell therapies for ARDS.



Purification of lipopolysaccharide-binding protein from bovine serum.  


Lipopolysaccharide-binding protein (LBP) plays a central role in presentation of bacterial-derived lipopolysaccharide (LPS; endotoxin) to leukocytes such as macrophages and neutrophils. Interaction of LBP with LPS is significant because LBP-LPS complexes promote activation of leukocytes and the immune system, which results in enhanced secretion of a spectrum of proinflammatory cytokines. An improved, simplified method was used to purify bovine LBP from serum. Methodology consisted of ion-exchange chromatography using Bio-Rex 70 resin, followed by gel-filtration chromatography (Sephacryl S-200 resin) of a selected ion-exchange fraction (0.22-0.50 M NaCl). Densitometric scans on silver-stained polyacrylamide gels of chromatographically-derived proteins indicated up to 88.7% purity of the resultant 64kD protein (bovine LBP) in the cleanest fractions. The isoelectric point of bovine LBP was determined to be 6.8. Identity of the protein was substantiated by western-blot analysis, and by N-terminus amino acid sequence analysis with favorable comparison to published sequence data from rabbit, human, and murine LBP Identity was corroborated by use of purified bovine LBP in bioassays which demonstrated enhanced tissue factor expression of LPS (1 ng ml(-1)-stimulated bovine alveolar macrophages. Tissue factor expression was inhibitable in these assays using anti-CD14 monoclonal antibodies, which is also consistent with LBP-mediated activation of cells. When bovine LBP was heated at 56 degrees C for 30 min, the biological activity was reduced by 50% in the macrophage-based bioassays. Biological activity of bovine LBP was completely destroyed by heating at 62 degrees C for 30 min, which compared favorably with data resulting from use of fetal bovine serum. PMID:8792567

Bochsler, P N; Yang, Z; Murphy, C L; Carroll, R C



Endotoxin-induced cytokine and chemokine expression in the HIV-1 transgenic rat  

PubMed Central

Background Repeated exposure to a low dose of a bacterial endotoxin such as lipopolysaccharide (LPS) causes immune cells to become refractory to a subsequent endotoxin challenge, a phenomenon known as endotoxin tolerance (ET). During ET, there is an imbalance in pro- and anti-inflammatory cytokine and chemokine production, leading to a dysregulated immune response. HIV-1 viral proteins are known to have an adverse effect on the immune system. However, the effects of HIV-1 viral proteins during ET have not been investigated. Methods In this study, HIV-1 transgenic (HIV-1Tg) rats and control F344 rats (n = 12 ea) were randomly treated with 2 non-pyrogenic doses of LPS (LL) to induce ET, or saline (SS), followed by a high challenge dose of LPS (LL+L, SS+L) or saline (LL+S, SS+S). The gene expression of 84 cytokines, chemokines, and their receptors in the brain and spleen was examined by relative quantitative PCR using a PCR array, and protein levels in the brain, spleen, and serum of 7 of these 84 genes was determined using an electrochemiluminescent assay. Results In the spleen, there was an increase in key pro-inflammatory (IL1?, IL-1?, IFN-?) and anti-inflammatory (IL-10) cytokines, and inflammatory chemokines (Ccl2, Ccl7, and Ccl9,) in response to LPS in the SS+L and LL+L (ET) groups of both the HIV-1Tg and F344 rats, but was greater in the HIV-1Tg rats than in the F344. In the ET HIV-1Tg and F344 (LL+L) rats in the spleen, the LPS-induced increase in pro-inflammatory cytokines was diminished and that of the anti-inflammatory cytokine was enhanced compared to the SS+L group rats. In the brain, IL-1?, as well as the Ccl2, Ccl3, and Ccl7 chemokines were increased to a greater extent in the HIV-1Tg rats compared to the F344; whereas Cxcl1, Cxcl10, and Cxcl11 were increased to a greater extent in the F344 rats compared to the HIV-1Tg rats in the LL+L and SS+L groups. Conclusion Our data indicate that the continuous presence of HIV-1 viral proteins can have tissue-dependent effects on endotoxin-induced cytokine and chemokine expression in the ET state.



Comparison of endotoxin assays using agricultural dusts.  


Endotoxins from gram-negative bacteria pose a significant respiratory hazard. Establishing dose-response relationships is problematic because there are no standard procedures for sampling and analysis. The goal of this study was to compare endotoxin analyses in six laboratories using Limulus-based assays for analysis of organic dusts from three agricultural environments: chicken barns, swine barns, and corn processing facilities. For each dust generation experiment 14 side-by-side air samples were collected on 37-mm glass fiber filters at flows of 1.8 L/min. Each laboratory was randomly allocated two filters from each of seven experiments per dust type. Three laboratories used the QCL-1000 endpoint assay, and three used the kinetic-QCL method. To eliminate variability among different lots, a single lot of Limulus amebocyte lysate for endpoint assays and one similar lot for kinetic assays was provided. Precision of assays performed within labs was very good, with pooled coefficients of variation for replicate samples ranging from 1 to 11% over all labs and all dust types. There were significant differences between laboratories for all three dust types (p < 0.01). The pattern of differences between labs varied by dust type. For chicken dust, labs using the endpoint method reported higher results than those using kinetic methods. For swine and corn dusts, labs using the kinetic method reported the highest endotoxin values. For chicken dust, results from all labs except A and B were highly correlated (r = 0.86-1.00). For swine dust, only labs B and E, and C and D were correlated. For corn, A, B, and D were significantly correlated with most other labs. In conclusion, statistical differences in performance between laboratories were apparent and may be related to the extraction and analytical methods. The results of this study will be useful for standardization of sampling and analysis of airborne endotoxin in agriculture. PMID:12486776

Reynolds, Stephen J; Thorne, Peter S; Donham, Kelley J; Croteau, Elizabeth A; Kelly, Kevin M; Lewis, Daniel; Whitmer, Mike; Heederik, D J J; Douwes, Jeroen; Connaughton, Ian; Koch, Sharon; Malmberg, Per; Larsson, Britt-Marie; Milton, Donald K


Regional blood flow during continuous low-dose endotoxin infusion  

SciTech Connect

Escherichia coli endotoxin (ET) was administered to adult rats by continuous IV infusion from a subcutaneously implanted osmotic pump (Alzet). Cardiac output and regional blood flow were determined by the radiolabeled microsphere method after 6 and 30 hr of ET or saline infusion. Cardiac output (CO) of ET rats was not different from time-matched controls, whereas arterial pressure was 13% lower after 30 hr of infusion. After both 6 and 30 hr of ET, pancreatic blood flow and percentage of cardiac output were lower than in controls. Estimated portal venous flow was decreased at each time point, and an increased hepatic arterial flow (significant after 30 hr) resulted in an unchanged total hepatic blood flow. Blood flow to most other tissues, including epididymal fat, muscle, kidneys, adrenals, and gastrointestinal tract, was similar between treatments. Maintenance of blood flow to metabolically important tissues indicates that the previously reported alterations in in vitro cellular metabolism are not due to tissue hypoperfusion. Earlier observations of in vitro myocardial dysfunction, coexistent with the significant impairment in pancreatic flow, raise the possibility that release of a myocardial depressant factor occurs not only in profound shock but also under less severe conditions of sepsis and endotoxemia.

Fish, R.E.; Lang, C.H.; Spitzer, J.A.



Endotoxin and cancer chemo-prevention.  


Reduced rates of lung cancer have been observed in several occupational groups exposed to high levels of organic dusts contaminated by endotoxin. The underlying anti-neoplastic mechanism of endotoxin may be an increased secretion of endogenous anti-neoplastic mediators and activation of the toll-like receptors (TLR). A detoxified endotoxin derivative, Monophosphoryl Lipid A (MPL(®)) is marketed in Europe since 1999 as part of the adjuvant systems in allergy vaccines for treatment of allergic rhino-conjunctivitis and allergic asthma. Over 200,000 patients have used them to date (nearly 70% in Germany). Since detailed exposure (MPL(®) dose and timing of administration) and individual data are potentially available, an observational follow-up study could be conducted in Germany to investigate the protective effect of MPL(®) against cancer, comparing cancer incidence in two groups of patients with allergic rhinitis: those treated with allergoids plus MPL(®) and those treated with a vaccine including the same allergoids but not MPL(®). The protective effect of MPL(®) could be quantified in ever and never smokers. If this proposed observational study provides evidence of protective effects, MPL(®) could be immediately used as a chemo-preventive agent since it is already in use as adjuvant in human vaccines against cancer. PMID:23692704

Mastrangelo, Giuseppe; Fadda, Emanuela; Cegolon, Luca



Role of outer membrane components in the nonspecific binding of Escherichia coli to cellulose  

Microsoft Academic Search

The involvement of lipopolysaccharide and outer membrane proteins in the binding ofEscherichia coli to cellulose was investigated. Cellulose binding was assayed in defined strains with or without O-antigenic polysaccharide and in mutants with defects in lipopolysaccharide core synthesis. Binding was also tested in strains lacking major outer membrane proteins. Optimal cellulose binding was exhibited by rough strains and was reduced

Vivian Hwa; Thomas Ferenci



Intralaboratory validation of kinetic chromogenic Limulus amebocyte lysate assay for bacterial endotoxin determination in anti-bothropic serum.  


Over the years, substituting in vitro biological methods for in vivo tests has posed an ever increasing challenge for researchers, including those who study the applications for snake antivenom. In the quality control of antivenons, the only official test recommended by pharmacopoeias for detecting pyrogenicity is the rabbit pyrogen test. In the present study, we propose intralaboratory validation of a method to replace the rabbit pyrogen test: in vitro determination of bacterial endotoxin in anti-bothropic serum (ABS) with quantitative kinetic chromogenic limulus amebocyte lysate (LAL) assay. The kinetic chromogenic LAL assay is specific to the detection of gram-negative bacterial endotoxin. The validation of the test involved the determination of performance parameters required by the Agęncia Nacional de Vigilância Sanitária Brasileira (ANVISA, the Brazilian National Health Surveillance Agency), the United States Food and Drug Administration (FDA) and the United States Pharmacopeia (USP) 35. In all experiments, the correlation coefficient of the curve obtained with the control standard endotoxin (CSE; Escherichia coli 055:B5 strain, range, 0.005-50EU/mL) was between -0.998 and -1.000; and the recovery of endotoxin added to the sample of ABS (0.5EU/mL) at the working dilution (1:10) followed the recuperation criteria (i.e., 50-200%). We performed six determinations, in each of which the coefficient of variation for the intermediate precision was between 5.6% and 13.8% (below the 15% threshold) and the accuracy was between 90.7% and 114.3% (within the acceptable range of 80-120%). The endotoxin concentration limit for the ABS was determined to be ?2.9EU/mL. The intralaboratory validation of the methodology was considered to have been successful because it met the criteria for all of the performance parameters. PMID:23912057

Fingola, Fernando F; Albertino, Sheila R G; Abrantes, Shirley de M P; Zamith, Helena P S



Endotoxin stimulates expression of the murine urokinase receptor gene in vivo.  

PubMed Central

The regulation of urokinase receptor (u-PAR) gene expression during endotoxemia was studied in vivo with a murine model system. Northern blot analysis demonstrated relatively high levels of u-PAR mRNA in mouse placenta, with intermediate levels in lung and spleen and very low levels in heart and kidney. No u-PAR mRNA could be detected in liver, gut, thymus, brain, or skeletal muscle. Intraperitoneal injection of endotoxin (lipopolysaccharide) increased the steady-state levels of u-PAR mRNA in most tissues examined. The greatest induction (sevenfold) was observed in the lung at 1 hour after injection. The cellular localization of u-PAR mRNA was assessed by in situ hybridization. In control mice, u-PAR mRNA was detected primarily in alveolar macrophages of the lung and lymphocytes of the spleen and thymus, although a specific signal was also present in other cell types. In general, endothelial cells lacked detectable u-PAR mRNA. The induction of u-PAR mRNA by lipopolysaccharide was apparent within 30 minutes and was localized to tissue macrophages, lymphocytes, and endothelial cells lining arteries and veins. At later times (1 to 3 hours), specialized epithelial cells present in gastrointestinal tract, bile ducts, and uterus were also positive for u-PAR mRNA. Induction of u-PAR in vivo by lipopolysaccharide may facilitate the extravasation and migration of leukocytes during inflammation. Images Figure 1 Figure 4 Figure 2 Figure 3 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9

Almus-Jacobs, F.; Varki, N.; Sawdey, M. S.; Loskutoff, D. J.



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




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



Lipopolysaccharide reduces sodium intake and sodium excretion in dehydrated rats.  


The objective of this study was to find out if lipopolysaccharide (LPS) administered intraperitoneally affects sodium and water intake and renal excretion in dehydrated rats. LPS (0.3-5 mg/kg b.w.) inhibited 0.3M NaCl intake induced by subcutaneous injection of the diuretic furosemide (FURO, 10 mg/kg b.w.) combined with the angiotensin converting enzyme inhibitor, captopril (CAP, 5 mg/kg b.w.). Only the highest doses of LPS (2.5 and 5 mg/kg) inhibited water intake induced by FURO/CAP. LPS (0.6 mg/kg) reduced urinary volume and sodium excretion, but had no effect on mean arterial pressure or heart rate of rats treated with FURO/CAP. LPS (0.3-5.0 mg/kg) abolished intracellular thirst and reduced by 50% the urine sodium concentration of rats that received 2 ml of 2M NaCl by gavage. LPS (0.3-5.0 mg/kg) also reduced thirst in rats treated with FURO alone (10 mg/rat sc). The results suggest that LPS has a preferential, but not exclusive, inhibitory effect on sodium intake and on intracellular thirst. The inhibition of hydro-mineral intake and the antinatriuresis caused by LPS in dehydrated rats may contribute to the multiple effects of the endotoxin on fluid and electrolyte balance and be part of the strategy to cope with infections. PMID:20977913

de Almeida, Roberto L; Constancio, Juliana; Vendramini, Regina C; Fracasso, José F; Menani, José V; De Luca, Laurival A



Hibiscus protocatechuic acid inhibits lipopolysaccharide-induced rat hepatic damage.  


Hibiscus protocatechuic acid (PCA), a phenolic compound found in the dried flowers of Hibiscus sabdariffa L. (Malvaceae), was demonstrated to have an antioxidant effect in vitro and in vivo, and an antitumor property in our previous study. In the present study, we used lipopolysaccharide (LPS, an endotoxin) to induce rat liver inducible nitric oxide synthase (iNOS), and found that pretreatment with PCA decreased the liver iNOS and the serum total nitrite induced by LPS. Our investigation showed that pretreatment of rats with PCA (0.2 and 0.5 mmol/kg dosed by gavage) for 5 days significantly decreased the serum levels of the hepatic enzyme markers alanine- and aspartate aminotransferase (ALT, alanine aminotransferase; AST, aspartate aminotransferase) induced by the 6-h treatment with LPS (i.p.; 5 mg/kg). Histopathological evaluation of the rat livers revealed that PCA reduced the incidence of liver lesions induced by LPS, including neutrophil infiltration, congestion, and liver cell swelling induced by LPS in rats. We conclude that PCA, an antioxidant, presents an inhibitory potential on iNOS and hepatic damage induced by LPS. PMID:12491040

Lin, W-L; Hsieh, Y-J; Chou, F-P; Wang, C-J; Cheng, M-T; Tseng, T-H



Glial response to lipopolysaccharide: possible role of endothelins.  


Glial inflammation plays a major role in the development of neurodegenerative diseases. Although endothelins (ETs) are known as modulators of inflammation in the periphery, little is known about their possible role in brain inflammation. Previously, we demonstrated that all three endothelins (ET-1, ET-2 and ET-3) enhanced unstimulated synthesis of the glial pro-inflammatory mediators, prostaglandin E? (PGE?) and nitric oxide (NO). In the present study, glial cells were stimulated in an in vitro model of inflammation by incubation with the bacterial endotoxin lipopolysaccharide (LPS). Indeed, the present study shows that ETs regulate basal and LPS-induced glial inflammation in an opposite fashion. Here we demonstrate that ETs significantly inhibited the LPS-induced glial synthesis of PGE? and NO, and each of the selective antagonists for ETA and ETB receptors (BQ123 and BQ788 respectively), significantly inhibited the ETs effects in LPS-treated cells. Similar results were observed when expression of key enzymes namely, cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in PG and NO synthesis respectively, was measured. ET-1 significantly enhanced the expression of both COX-2 and iNOS. Whereas, it inhibited the LPS-induced expression of both enzymes. These observations suggest a novel neuro-immune feedback pathway through which inflammatory mediators' synthesis is initially enhanced by ETs and are eventually blocked by the same neuropeptide when excessive production of inflammatory mediators occurs following an inflammatory insult. PMID:20863865

Filipovich-Rimon, Talia; Fleisher-Berkovich, Sigal



Key structures of bacterial peptidoglycan and lipopolysaccharide triggering the innate immune system of higher animals: Chemical synthesis and functional studies  

PubMed Central

Chemistry-based investigation is reviewed which led to identification of the active entities responsible for the immunostimulating potencies of peptidoglycan and lipopolysaccharide. Though these glycoconjugates which ubiquitously occur in wide range of bacteria as the essential components of their cell envelopes have long been known to enhance the immunological responses of higher animals, neither the precise chemical structures required nor the mechanism of their action remained to be elucidated until early 1970s. Chemical synthesis of partial structures of peptidoglycan proved N-acetylmuramyl-L-alanyl-D-isoglutamine to be the minimum structure responsible for the activity and led to later identification of its receptor protein Nod2 present in animal cells. Another active partial structure of peptidoglycan, ?-D-glutamyl-meso-diaminopimelic acid, and its receptor Nod1 were also identified as well. With regard to lipopolysaccharide, its glycolipid part named lipid A was purified and the structure studied. Chemically synthesized lipid A according to the newly elucidated structure exhibited full activity described for lipopolysaccharide known as endotoxin. Synthetic homogeneous lipid A and its structural analogues and labeled derivatives enabled precise studies of their interaction with receptor proteins and the mechanism of their action. Chemical synthesis of homogeneous partial structures of peptidoglycan and lipopolysaccharide gave unequivocal evidences for the concept that definite small molecular parts of these complex macromolecular bacterial glycoconjugates are specifically recognized by their respective receptors and trigger our defense system now widely recognized as innate immunity.

Kusumoto, Shoichi; Fukase, Koichi; Shiba, Tetsuo




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 inactivation by selected drinking water treatment oxidants  

Microsoft Academic Search

Exposure to endotoxins in treated drinking water can occur through ingestion, dermal abrasions, inhalation of water vapor, intravenous injection or during dialysis. While the risks associated with endotoxin ingestion and entry through dermal abrasions are not well quantified, adverse effects of intravenous injection and dialysis are well known and some studies indicate that inhalation of moisture-laden air may impact human

William B Anderson; Colin I Mayfield; D. George Dixon; Peter M Huck



General effect of endotoxin on glucocorticoid receptors in mammalian tissues  

SciTech Connect

Considering the ubiquitous nature of glucocorticoid actions and the fact that endotoxin inhibits glucocorticoid action in the liver, we proposed to examine whether endotoxin affected extrahepatic actions of glucocorticoids. Fasted C57BL/6J mice were injected intraperitoneally with endotoxin (LD50) at 0800 and were killed 6 h later. Control mice were injected with an equal volume of saline. /sup 3/H-dexamethasone binding, measured by a new cytosol exchange assay utilizing molybdate plus dithiothreitol, in liver, kidney, skeletal muscle, spleen, lung, and heart tissue was significantly lower in treated than in control mice. The equilibrium dissociation constants were not significantly different, but the number of available binding sites in each tissue was reduced by endotoxin treatment. Phosphoenolpyruvate carboxykinase activity was significantly reduced in liver but not in kidney. Endotoxin treatment lowered glycogen content in liver but not in skeletal muscle. The reduction observed in the a form of liver glycogen synthase due to endotoxin was not seen in skeletal muscle glycogen synthase a. These data support the proposal that endotoxin or a mediator of its action inhibits systemic glucocorticoid action. The results also emphasize the central role of the liver in the metabolic disturbances of the endotoxin-treated mouse.

Stith, R.D.; McCallum, R.E.



[Mechanisms of the liver anti-endotoxin defence].  


Current knowledge of immunocellular and lipoprotein mechanisms of the liver-induced anti-endotoxin tolerance has been summarized. The role of T regulatory cells, different macrophage phenotypes, high density lipoproteins, oxidized low density lipoproteins and their receptors as the key players in mechanism of tolerance to endotoxin has been discussed. PMID:22708412

Panchenko, L F; Pirozhkov, S V; Tereblina, N N; Naumova, T A; Voronets, V Iu; Sho?bonov, B B


Reduced lactational performance following intravenous endotoxin administration to dairy cows.  


Nonpregnant lactating cows were given 100 micrograms of endotoxin via the jugular vein to determine effects of intravenous endotoxin administration on mammary inflammation and lactational performance. At the first milking (11 h) posttreatment, milk yield was reduced 33%. Milk fat percentage was elevated at this time, but lactose concentration was decreased. Milk yield and composition returned to pretreatment levels within 2 d. Clinical mastitis was not induced by endotoxin treatment, but milk SCC, NAGase, serum albumin, and lactoferrin were increased by 50%. This increase was small compared with increases during mastitis and may have resulted from lower milk volume. These results support the hypothesis that part of the reduced lactational performance during endotoxin mastitis is mediated by systemic pathophysiological responses and indicate that intravenous endotoxin administration may be a useful model to study adverse effects of infectious disease on lactational performance. PMID:1744270

Shuster, D E; Harmon, R J; Jackson, J A; Hemken, R W



Bacterial infection and endotoxin in female reproductive tract in rats: correlation with the developmental status of preimplantation embryos.  


During mammalian preimplantation development, a substantial numbers of embryos are believed to be lost for reasons that are unclear. Using female rats, we investigated whether the developmental status of embryos is influenced by bacterial infection and endotoxin in the reproductive tract. From the vagina of cycling rats (n = 11), 21 bacterial isolates were identified; they were Streptococcus faecalis (S. faecalis; 38%), Escherichia coli (E. coli; 19%), Acinetobactor calcoaceticus (A. calcoaceticus; 14%), and coagulase negative staphylococcus (14%), Micrococcus sp. (5%), Bacillus subtilis (B. subtilis; 5%) and Proteus vulgaris (P. vulgaris; 5%). From the vagina of day 4 pregnant rats (n = 12), 26 isolates were identified; they were S. faecalis (23%), A. calcoaceticus (23%), E. coli (15%), Micrococcus sp. (15%), B. subtilis (8%), P. vulgaris (4%), Staphylococcus aureus (4%), beta-hemolytic streptococcus (4%) and Pseudomonas aeruginosa (4%). Gram negative bacteria found in the vagina of cycling and day 4 pregnant rats were 38% and 46%, respectively. In both, bacterial load was 10(3)-10(5) colony forming units and there was no association with the abnormality of the recovered embryos. However, in two day 4 pregnant animals, pathogenic bacteria (Staphylococcus aureus and beta-hemolytic streptococcus) were isolated and embryos recovered from them were degenerated and deformed. The vagina of day 9 pregnant animals (n = 7) were, however, sterile. Consistently, in all animals, the upper reproductive tract (uterus and oviduct) was devoid of any bacteria and no anaerobic bacteria were isolated from any part of the tract. The levels of endotoxin in the vagina of cycling and day 4 pregnant rats were 1.35 +/- 0.1 and 1.17 +/- 0.1 endotoxin units (EU), respectively. It was undetectable in the oviduct and uterus of all animals (n = 5) except one which showed high levels of endotoxin in uterus (4.5 EU) and oviduct (2.2 EU) and the animal also produced degenerated and deformed embryos. These results indicate that common bacterial flora of vagina may not affect embryo development and the presence of pathogenic bacteria in the vagina and/or endotoxin in reproductive tract could be detrimental to viability of gametes and preimplantation embryos in rats. PMID:9854425

Ain, R; Rao, J; Peter, A T; Vijaykumar, B R; Sridhar, H; Satish, K S; Seshagiri, P B



Endotoxins in tobacco smoke: shifting tobacco industry positions.  


In the 1980s, the tobacco industry started a campaign to divert attention away from secondhand tobacco smoke (SHS) as a major source of indoor air pollution in workplaces by highlighting the roles of other indoor air pollutants. The industry, working through "third parties," highlighted endotoxins, naturally occurring substances that cause numerous inflammatory reactions in humans, as an alternative explanation to SHS as causing indoor air problems. In 1995, Hasday and colleagues were the first to present findings that cigarette smoke contains significant quantities of endotoxins. This discovery surprised tobacco industry scientists. The 1999 publication of the full Hasday et al. findings received only limited media attention but got the full attention of Philip Morris scientists concerned about a new public health issue and a new basis for regulation of workplace smoking by the U.S. Occupational Safety and Health Administration, which already regulated workplace endotoxin exposures from other sources. Philip Morris undertook an internal endotoxin research project to test the Hasday et al. findings and to determine if endotoxin-free cigarettes were possible. Although experiments were conducted to remove endotoxin from the tobacco, there is no evidence that they were successful. Following confirmation of SHS as an important source of endotoxins, the scientist promoting endotoxins as an important indoor air pollutant for the tobacco industry softened his position on the role of endotoxins as indoor pollutants. The presence of endotoxins in SHS provides an additional mechanism for the adverse effects of SHS that should be researched further, and the risk of exposure should be assessed. PMID:17852769

Barnes, Richard L; Glantz, Stanton A



Endotoxin and CD14 in the progression of biliary atresia  

PubMed Central

Background Biliary atresia (BA) is a typical cholestatic neonatal disease, characterized by obliteration of intra- and/or extra-hepatic bile ducts. However, the mechanisms contributing to the pathogenesis of BA remain uncertain. Because of decreased bile flow, infectious complications and damaging endotoxemia occur frequently in patients with BA. The aim of this study was to investigate endotoxin levels in patients with BA and the relation of these levels with the expression of the endotoxin receptor, CD14. Methods The plasma levels of endotoxin and soluble CD14 were measured with a pyrochrome Limulus amebocyte lysate assay and enzyme-linked immunosorbent assay in patients with early-stage BA when they received the Kasai procedure (KP), in patients who were jaundice-free post-KP and followed-up at the outpatient department, in patients with late-stage BA when they received liver transplantation, and in patients with choledochal cysts. The correlation of CD14 expression with endotoxin levels in rats following common bile duct ligation was investigated. Results The results demonstrated a significantly higher hepatic CD14 mRNA and soluble CD14 plasma levels in patients with early-stage BA relative to those with late-stage BA. However, plasma endotoxin levels were significantly higher in both the early and late stages of BA relative to controls. In rat model, the results demonstrated that both endotoxin and CD14 levels were significantly increased in liver tissues of rats following bile duct ligation. Conclusions The significant increase in plasma endotoxin and soluble CD14 levels during BA implies a possible involvement of endotoxin stimulated CD14 production by hepatocytes in the early stage of BA for removal of endotoxin; whereas, endotoxin signaling likely induced liver injury and impaired soluble CD14 synthesis in the late stages of BA.



Interaction of endotoxins with Toll-like receptor 4 correlates with their endotoxic potential and may explain the proinflammatory effect of Brucella spp. LPS  

Microsoft Academic Search

Endotoxins displaying differences in the chemical structure of their lipid A were used to induce the expression of chemokines in the human monocytic THP-1 cell line. LPS from two enterobacterial species such as Escherichia coli and Yersinia enterocolitica induced mRNA expression of IFN-c- inducible protein (IP)-10, macrophage-inflammatory protein (MIP)-1a, MIP-1b, monocyte chemoattractant protein (MCP)-1 and IL-8. LPS from the non-enterobacterial

Ana I. Duenas; Antonio Orduna; Mariano Sanchez Crespo; Carmen Garcia-Rodriguez



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



Home Endotoxin Exposure and Wheeze in Infants: Correction for Bias Due to Exposure Measurement Error  

PubMed Central

Exposure to elevated levels of endotoxin in family-room dust was previously observed to be significantly associated with increased wheeze in the first year of life among a cohort of 404 children in the Boston, Massachusetts, metropolitan area. However, it is likely that family-room dust endotoxin was a surrogate for airborne endotoxin exposure. Therefore, a related substudy characterized the relationship between levels of airborne household endotoxin and the level of endotoxin present in house dust, in addition to identifying other significant predictors of airborne endotoxin in the home. We now reexamine the relationship between endotoxin exposure and wheeze under the assumption that the level of airborne endotoxin in the home is the exposure of interest and that the amount of endotoxin in household dust is a surrogate for this exposure. We applied a measurement error correction technique, using all available data to estimate the effect of endotoxin exposure in terms of airborne concentration and accounting for the measurement error induced by using house-dust endotoxin as a surrogate measure in the portion of the data in which airborne endotoxin could not be directly measured. After adjusting for confounding by lower respiratory infection status and race/ethnicity, endotoxin exposure was found to be significantly associated with a nearly 6-fold increase in prevalence of wheeze for a one interquartile range increase in airborne endotoxin (95% confidence interval, 1.2–26) among the 360 children in households with dust endotoxin levels between the 5th and 95th percentiles.

Horick, Nora; Weller, Edie; Milton, Donald K.; Gold, Diane R.; Li, Ruifeng; Spiegelman, Donna



Protective Effects of Medium-Chain Triglycerides on the Liver and Gut in Rats Administered Endotoxin  

PubMed Central

Objective To determine if medium-chain triglycerides (MCTs) prevent organ injuries and mortality in rats administered endotoxin and to investigate effects of MCT on the gut. Summary Background Data Since dietary MCTs prevent alcohol-induced liver injury by inhibiting activation of Kupffer cells in the enteral feeding model, the authors hypothesized that MCT could prevent deleterious conditions in endotoxemia. Methods After a preliminary experiment determined the optimal dose of MCT, rats were given MCT (5 g/kg per day) or the same dose of corn oil by gavage daily for 1 week. Then, lipopolysaccharide (LPS) was administered intravenously and survival was assessed for the next 24 hours. For analysis of mechanisms, rats were killed 9 hours after LPS injection and serum and liver sections were collected. To investigate effects of MCT on the gut, pathologic change, permeability, and microflora were assessed. Kupffer cells isolated by collagenase digestion and differential centrifugation were used for endotoxin receptor CD14 immunoblotting, phagocytic index, and TNF-? production assay. Results All rats given corn oil died after LPS administration; however, this mortality was prevented by MCT in a dose-dependent manner. Rats given corn oil showed liver injury after LPS administration. In contrast, MCT prevented this pathologic change nearly completely. MCT blunted CD14 expression on the Kupffer cells and TNF-? production by isolated Kupffer cells; however, there were no differences in phagocytic index between the two groups. The length of the intestinal epithelium was increased in the MCT group compared to the corn oil group. Further, after LPS administration, increases in gut permeability and injury were prevented by MCT. Importantly, MCT also prevented hepatic energy charge and gut injuries in this condition. Conclusions Enteral feeding using MCT could be a practical way of protecting the liver and intestine during endotoxemia.

Kono, Hiroshi; Fujii, Hideki; Asakawa, Masami; Yamamoto, Masayuki; Matsuda, Masanori; Maki, Akira; Matsumoto, Yoshiro



Carnitine deprivation adversely affects cardiovascular response to bacterial endotoxin (LPS) in the anesthetized neonatal pig.  


Sepsis and endotoxemia are important stressors for the neonate. Newborn infants receiving total parenteral nutrition are routinely deprived of carnitine. To investigate whether carnitine deprivation affects the neonate's ability to respond to endotoxin, 19 newborn piglets received parenteral nutrition for 2-3 weeks that was either carnitine free (CARN-) or supplemented (CARN+) with L-carnitine (400 mg/L). Cardiovascular performance, i.e., heart rate; blood pressure (BP); cardiac output (CO); systemic vascular resistance (SVR), and metabolic response, i.e., plasma glucose; lactate; tumor necrosis factor alpha; tissue nitric oxide; and urinary nitrites, were studied serially in anesthetized piglets for 3 h after endotoxin (lipopolysaccharide (LPS), 250 microg/kg intravenous bolus) or vehicle administration. Plasma and tissue carnitine values were lower in CARN- than in CARN+ piglets. Prior to LPS, no differences were found for most parameters (excepting lower diastolic BP and SVR in CARN- animals). Systolic, diastolic, and mean BP fell after LPS but recovered by the end of the experiment. Nadirs were lower in CARN- than in CARN+ piglets. CO tended to be higher in CARN- than in CARN+ animals and fell after LPS. SVR fell after LPS and was lower in CARN- than in CARN+ piglets. LPS-treated animals transiently increased urinary flow. By all measures (plasma tumor necrosis factor alpha, glucose and lactate, tissue nitric oxide, and urinary nitrite excretion), LPS provocation was similar for both groups. Chronologically, BP changes were more closely related to SVR than to CO. Our findings suggest that carnitine deprivation diminishes tissue carnitine concentrations and adversely affects cardiovascular response to LPS, in part mediated by the peripheral vasculature. PMID:9840655

Penn, D; Zhang, L; Bobrowski, P J; Quinn, M; Liu, X; McDonough, K H



miR-146a is critical for endotoxin-induced tolerance: IMPLICATION IN INNATE IMMUNITY.  


The human toll-like receptor 4 (TLR4) pathway is activated in response to lipopolysaccharide (LPS), and subsequent signal transductions lead to the production of cytokines such as tumor necrosis factor-alpha (TNF-alpha) by innate immune cells. Defects in innate immune response may contribute to the overproduction of TNF-alpha leading to systemic inflammation and diseases. Thus, the innate immune response needs to be tightly regulated by elaborate mechanisms to control its onset and termination. LPS tolerance is a state of hyporesponsiveness to subsequent LPS challenge and is achieved by monocytic cells after prolonged exposure to LPS. In this report, kinetics of endotoxin-responsive microRNAs expression analysis revealed a unique pattern of gradual increase for miR-146a starting 4 h after LPS stimulation in THP-1 cells and continued up to 35-fold over 24 h. Conversely, TNF-alpha increased up to 4 h and then decreased gradually implicating a negative correlation with miR-146a progression. The characteristic up-regulation of miR-146a toward subsequent LPS challenge in THP-1 cells was studied. Strikingly, microRNA expression analysis during the tolerized state of THP-1 cells showed only miR-146a overexpression suggesting its important role in LPS tolerance. In addition, LPS tolerance was dependent on a LPS-priming dose and associated miR-146a up-regulation. LPS-tolerized cells were observed to regain responsiveness in TNF-alpha production 22 h after LPS removal correlating with a decrease in miR-146a level. Transfection of miR-146a into THP-1 cells mimicked LPS priming, whereas transfection of miR-146a inhibitor largely abolished LPS tolerance. Thus our studies demonstrated that miR-146a is critical for the in vitro monocytic cell-based endotoxin tolerance. PMID:19840932

Nahid, Md A; Pauley, Kaleb M; Satoh, Minoru; Chan, Edward K L



Endotoxin priming improves clearance of Pseudomonas aeruginosa in wild-type and interleukin-10 knockout mice.  


Endotoxin (lipopolysaccharide [LPS]) tolerance is an altered state of immunity caused by prior exposure to LPS, in which production of many cytokines, including gamma interferon (IFN-gamma) and interleukin-12 (IL-12), are reduced but secretion of the anti-inflammatory cytokine IL-10 is increased in response to a subsequent LPS challenge. This pattern of cytokine production is also characteristic of postinflammatory immunosuppression. Therefore, we hypothesized that LPS-primed mice would exhibit an impaired ability to respond to systemic infection with the opportunistic pathogen Pseudomonas aeruginosa. We further hypothesized that depletion of IL-10 would reverse the endotoxin-tolerant state. To test this hypothesis, systemic clearance of Pseudomonas aeruginosa was measured for LPS-primed wild-type and IL-10-deficient mice. LPS-primed wild-type mice exhibited significant suppression of LPS-induced IFN-gamma and IL-12 but increased IL-10 production in blood and spleen compared to levels exhibited by saline-primed wild-type mice. The suppressed production of IFN-gamma and IL-12 caused by LPS priming was ablated in the spleens, but not blood, of IL-10 knockout mice. LPS-primed wild-type mice cleared Pseudomonas aeruginosa from lungs and blood more effectively than saline-primed mice. LPS-primed IL-10-deficient mice were particularly efficient in clearing Pseudomonas aeruginosa after systemic challenge. These studies show that induction of LPS tolerance enhanced systemic clearance of Pseudomonas aeruginosa and that this effect was augmented by neutralization of IL-10. PMID:16239532

Varma, Tushar K; Durham, Megan; Murphey, Erle D; Cui, Weihua; Huang, Zhiyu; Lin, Cheng Y; Toliver-Kinsky, Tracy; Sherwood, Edward R



Lipopolysaccharides of Brucella abortus and Brucella melitensis Induce Nitric Oxide Synthesis in Rat Peritoneal Macrophages  

Microsoft Academic Search

Received 28 October 1999\\/Returned for modification 16 November 1999\\/Accepted 6 December 1999 Smooth lipopolysaccharide (S-LPS) and lipid A of Brucella abortus and Brucella melitensis induced the production of nitric oxide (NO) by rat adherent peritoneal cells, but they induced lower levels of production of NO than Escherichia coli LPS. The participation of the inducible isoform of NO synthase (iNOS) was




Chlamydia1 lipopolysaccharide: Chemical and antigenic structure, biosy n t hesis and bio medica I application  

Microsoft Academic Search

The obligate intracellular gram-negative bacterium Chlamydia contains as a major surface antigen a lipopolysaccharide (LPS) which harbours in its saccharide moiety a genus-specific epitope composed of a linear trisaccharide of 3-deoxy-D-manno- octulopyranosonic acid (Kdo) of the sequence aKdo-(2+8)-~~Kdo-(2+4)-aKdo. The structure was established on LPS of recombinant E. coli bacteria transformed with a plasmid carrying the gene for the chlamydia1 Kdo

H. Brade; L. Brade; S. Mbau; M. Lukacova; U. Mamat; A. Rozalski; K. Zych; P. Kosma


Effect of Lipopolysaccharide Infusion on Serum Macromineral and Vitamin D Concentrations in Dairy Cows1  

Microsoft Academic Search

Four multiparous lactating cows (175 to 220 d in milk) were used in a 4 × 4 Latin square design to assess the effects of four doses (0.0, 0.5, 1.0, 1.5 µg\\/kg of body weight) of lipopolysaccharide (LPS; Escherichia coli 0111:B4) on circulating concentrations of macrominer- als and vitamin D metabolites. Treatments were dis- solved in 100 ml of sterile

M. R. Waldron; B. J. Nonnecke; T. Nishida; R. L. Horst; T. R. Overton



Intestinal radiation syndrome: sepsis and endotoxin  

SciTech Connect

Rats were whole-body irradiated with 8-MeV cyclotron-produced neutrons and /sup 137/Cs ..gamma.. rays to study the role of enteric bacteria and endotoxin in the intestinal radiation syndrome. Decrease in intestinal weight was used as an index of radiation-induced breakdown of the mucosa. Neutron and ..gamma..-ray doses that were sublethal for intestinal death resulted in a dose-dependent decrease in intestinal weight, reaching minimal values 2 to 3 days after exposure, followed by recovery within 5 days after irradiation. Neutron and photon doses that caused intestinal death resulted in greater mucosal breakdown with little or no evidence of mucosal recovery. The presence of fluid in the intestine and diarrhea, but not bacteremia or endotoxemia, were related to mucosal breakdown and recovery. Neither sepsis nor endotoxin could be detected in liver samples taken at autopsy from animals which died a short time earlier from intestinal injury. These results suggest that overt sepsis and endotoxemia do not play a significant role in the intestinal radiation syndrome.

Geraci, J.P.; Jackson, K.L.; Mariano, M.S.



Lipopolysaccharide Induces Endoplasmic Store Ca2+-Dependent Inflammatory Responses in Lung Microvessels  

PubMed Central

The pulmonary microvasculature plays a critical role in endotoxin-induced acute lung injury. However, the relevant signaling remain unclear. Specifically the role of endothelial Ca2+ in the induction of endotoxin-mediated responses in lung microvessels remains undefined. Toward elucidating this, we used the isolated blood-perfused rat lung preparation. We loaded microvessels with the Ca2+ indicator, Fura 2 AM and then determined Ca2+ responses to infusions of lipopolysaccharide (LPS) into the microvessels. LPS induced a more than two-fold increase in the amplitude of cytosolic Ca2+ oscillations. Inhibiting inositol 1,4,5 trisphosphate receptors on endoplasmic reticulum (ER) Ca2+ stores with Xestospongin C (XeC), blocked the LPS-induced increase in the Ca2+ oscillation amplitude. However, XeC did not affect entry of external Ca2+ via plasma membrane Ca2+ channels in lung microvascular endothelial cells. This suggested that LPS augmented the oscillations via release of Ca2+ from ER stores. In addition, XeC also blocked LPS-mediated activation and nuclear translocation of nuclear factor-kappa B in lung microvessels. Further, inhibiting ER Ca2+ release blunted increases in intercellular adhesion molecule-1 expression and retention of naďve leukocytes in LPS-treated microvessels. Taken together, the data suggest that LPS-mediated Ca2+ release from ER stores underlies nuclear factor-kappa B activation and downstream inflammatory signaling in lung microvessels. Thus, we show for the first time a role for inositol 1,4,5 trisphosphate-mediated ER Ca2+ release in the induction of LPS responses in pulmonary microvascular endothelium. Mechanisms that blunt this signaling may mitigate endotoxin-induced morbidity.

Kandasamy, Kathirvel; Bezavada, Lavanya; Escue, Rachel B.; Parthasarathi, Kaushik



Neonatal lipopolysaccharide exposure exacerbates stress-induced suppression of LH pulse frequency in adulthood  

PubMed Central

Early life exposure to immunological challenge has programming effects on the adult hypothalamo-pituitary-adrenocortical (HPA) axis stress responsivity and stress is known to suppress GnRH pulse generator activity, especially LH pulses. We investigated the effects of neonatal exposure to endotoxin on stress-induced suppression of pulsatile LH secretion and the involvement of corticotropin-releasing factor (CRF) receptor mechanisms in adult rats. Pups at 3 and 5 days of age were administered lipopolysaccharide (LPS: 50 ?g/kg, ip). At 12 week of age they were ovariectomized and implanted sc 17?-estradiol capsules and iv cannulae. Blood samples (25?l) were collected every 5 min for 5 h for LH measurement. After 2 h of sampling rats were given LPS (25 ?g/kg, iv). CRF, CRF-R1 and CRF-R2 receptor mRNA was determined by RT-PCR in medial preoptic area (mPOA) micropunches collected at 3 h after LPS administration. There was no difference in basal LH pulse frequency between neonatal-LPS and neonatal-saline controls. However, neonatal endotoxin treated rats exhibited a significantly greater LPS stress-induced suppression of LH pulse frequency. Basal mPOA CRF-R1 expression was unchanged in neonatal-LPS and neonatal-saline treated rats. However, CRF-R1 expression was significantly increased in response to LPS stress in neonatal-LPS treated animals, but not in neonatal-saline controls. CRF and CRF-R2 expression was unchanged in all treatment groups. These data demonstrate that exposure to bacterial endotoxin in early neonatal life programmes long-term sensitization of the GnRH pulse generator to the inhibitory influence of stress in adulthood, an effect that might involve up-regulation of CRF-R1 expression in the mPOA.

Li, X.F.; Kinsey-Jones, J.S.; Knox, A.M.I.; Wu, X. Q.; Tahsinsoy, D.; Brain, S.D.; Lightman, S.L.; O'Byrne, K.T.



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:



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.

Leiva-Salcedo, Elias; Coddou, Claudio; Rodriguez, Felipe E.; Penna, Antonello; Lopez, Ximena; Neira, Tanya; Fernandez, Ricardo; Imarai, Monica; Rios, Miguel; Escobar, Jorge; Montoya, Margarita; Huidobro-Toro, J. Pablo; Escobar, Alejandro; Acuna-Castillo, Claudio



Lipopolysaccharide inhibits the channel activity of the P2X7 receptor.  


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