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1

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. PMID:12045108

Raetz, Christian R. H.; Whitfield, Chris

2008-01-01

2

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. PMID:22723968

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

2012-01-01

3

Studies on the interaction of Escherichia coli endotoxin with erythrocyte membranes.  

PubMed

Escherichia coli lipopolysaccharide (endotoxin) alters the stability of erythrocytes to hypotonic lysis although the nature and magnitude of the effect varied with temperature and with the type of red blood cell examined. Evidence has been obtained suggesting a possible modulatory role of membrane lipids in governing the molecular consequences of membrane-endotoxin interaction. The marked effect of temperature on the stabilization of red cells by endotoxin was not attributable to variations in toxin binding and was not observed with more conventional structurally unrelated antihemolytic agents. Although chemical modifications which alter the toxicity of endotoxin in vivo also modify its ability to stabilize erythrocytes in vitro, no simple relationship between in vivo endotoxin toxicity and in vitro effects on erythrocyte stability was apparent. The critical dependence of endotoxin antihemolytic effects in vitro on molecular structure may offer a convenient means of assessing the homogeneity of these preparations before performing experiments in vivo. PMID:6751512

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

1982-07-01

4

Isolation of two protein-free and chemically different lipopolysaccharides from Bordetella pertussis phenol-extracted endotoxin.  

PubMed Central

Endotoxin prepared from several Bordetella pertussis strains in both immunological phases I and IV gave two lipopolysaccharide peaks (LPS-I and LPS-II) when analyzed on hydroxylapatite columns in a phosphate buffer containing 0.1% sodium dodecyl sulfate; these lipopolysaccharides, present in the ratio of 2:3, are true endotoxins by both chemical and biological criteria. Endotoxins isolated from Escherichia coli, Salmonella typhimurium, and Shigella flexneri gave single lipopolysaccharide peaks when analyzed by the same procedure. Upon hydrolysis with acetic acid (pH 3.4) at 100 degrees C for 1 h, LPS-I released a polysaccharide (PS-I); the linkage broken was that of the glycosidic bond of a non-phosphorylated 3-deoxy-oct-2-ulosonic acid. Treatment with 0.25 M mineral acid at 100 degrees C for 30 min was required to free the polysaccharide moiety (PS-II) of LPS-II, the linkage broken being the glycosidic bond of a phosphorylated 3-deoxy-oct-2-ulosonic acid. Chemical and physical differences of the polysaccharide moieties PS-I and PS-II present in LPS-I and LPS-II have been described previously (25). By using the technique of 125I labeling, it was shown that the totality of labeled proteins present in the endotoxin extracted from Bordetella pertussis by the phenol-water procedure could be separated from the lipopolysaccharide by column chromatography on hydroxylapatite; it follows that these proteins are not linked by covalent bonds to the lipopolysaccharide. PMID:6249793

Le Dur, A; Chaby, R; Szabó, L

1980-01-01

5

Administration of Endotoxin Associated with Lipopolysaccharide Tolerance Protects Mice against Fungal Infection  

Microsoft Academic Search

Lipopolysaccharide (LPS) pretreatment of mice resulted in a significantly enhanced survival after dissem- inated Cryptococcus neoformans infection. The survival was associated with reduced fungal burden in tissues. LPS-pretreated mice had lower levels of cytokines in blood, spleen, and lungs and higher levels in brain. Pentoxifylline abolished the beneficial effect of LPS pretreatment. Whether the induction of endotoxin tolerance leads to

NAIMA RAYHANE; CATHERINE FITTING; OLIVIER LORTHOLARY; FRANCOISE DROMER; JEAN-MARC CAVAILLON

2000-01-01

6

The effects of Twist-2 on liver endotoxin tolerance induced by a low dose of lipopolysaccharide.  

PubMed

Endotoxin tolerance is an important mechanism for preventing uncontrolled inflammatory cytokine production in bacterial sepsis. However, its molecular mechanisms remain largely unknown. It was reported that Twist-2 protein was a negative regulator for cytokine signaling by repressing the nuclear factor (NF)-?B-dependent cytokine pathway. However, the relationship between Twist-2 and endotoxin tolerance is unclear. Endotoxin tolerance models of BABL/c mice and isolated Kupffer cells (KCs) were established to observe the changes of Twist-2 during endotoxin tolerance. Then, Twist-2 shRNA was used to specifically inhibit Twist-2 gene in KCs to further explore the role of Twist-2 in endotoxin tolerance. The expression of Twist-2 was analyzed by immunohistochemistry, reverse transcription polymerase chain reaction, and Western blotting, respectively. The responses to lipopolysaccharide were assessed by the activation of nuclear factor-?B and the production of tumor necrosis factor-?. The histopathologic changes in the liver of the non-endotoxin tolerance group were more serious than those of the endotoxin tolerance group. Endotoxin tolerance also led to less activation of nuclear factor-?B, lower expression levels of tumor necrosis factor-? mRNA, and more expression of Twist-2 than those of non-endotoxin tolerance group in liver and KCs. Moreover, the inhibitive effects partly weaken in KCs transfected with Twist-2 shRNA. Twist-2 was involved in endotoxin tolerance through inhibiting NF-?B trans-activation and cytokines transcriptional activities. It may be a new target for the clinical treatment of sepsis and other inflammatory diseases. PMID:24005898

Li, Peizhi; Li, Min; He, Kun; Zhong, Kaichan; Gong, Jianping; You, Haibo

2014-02-01

7

Bacterial lipopolysaccharide (endotoxin) enhances expression and secretion of beta 2 interferon by human fibroblasts  

PubMed Central

The human beta 2 interferon (IFN-beta 2) gene, a gene that also codes for B cell differentiation factor 2 (BSF-2), plasmacytoma/hybridoma growth factor (HGF), and hepatocyte-stimulating factor (HSF), is expressed in a variety of lymphoid and nonlymphoid tissues. Endotoxin, or bacterial lipopolysaccharide (LPS) preparations derived from the outer membrane of Escherichia coli or Salmonella typhimurium rapidly elevate IFN-beta 2 mRNA level in human skin fibroblasts (FS-4 strain). E. coli-derived LPS enhances IFN-beta 2 mRNA expression in FS-4 fibroblasts at a concentration as low as 0.3 ng/ml; this response is near-maximal in the range of 0.1-1 microgram/ml LPS. The increase in IFN-beta 2 mRNA level caused by LPS in FS-4 cells is detected within 30 min after addition of LPS, is sustained for at least 20 h thereafter, appears to involve the protein kinase C signal transduction pathway, does not require new protein synthesis, and is inhibited by dexamethasone in a dose-dependent fashion (in the range 10(-6)-10(-8) M). Cultures of LPS-treated FS-4 cells exhibit an antiviral state against vesicular stomatitis virus, which can be prevented by anti-IFN- beta antiserum. Medium obtained from LPS-treated FS-4 cell cultures enhances the number of immunoglobulin-secreting cells in cultures of human B-lymphoblastoid (CESS) cells. Thus, LPS may trigger a number of host defense mechanisms in the course of infection due to Gram-negative bacteria by enhancing IFN-beta 2 production by the ubiquitous fibroblast. PMID:2824651

1987-01-01

8

Gram-negative endotoxin lipopolysaccharide induces cardiac hypertrophy: Detrimental role of Na(+)-Ca(2+) exchanger.  

PubMed

Several molecular pathways involved in the development of cardiac hypertrophy are triggered by perturbation of intracellular Ca(2+) homeostasis. Within the heart, Na(+)/Ca(2+) exchanger 1 (NCX1) is one of the main determinant in controlling Ca(2+) homeostasis. In cardiac hypertrophy and heart failure NCX1 expression and activity have been reported to be altered. It has been shown that chronic bacterial infections (sepsis, endocarditis, and myocarditis) can promote cardiac hypertrophy. Bacterial stressors, such as the Gram-negative endotoxin lipopolysaccharide (LPS), can directly or indirectly affect intracellular Ca(2+) homeostasis in the heart and induce the development of cardiac hypertrophy. The present study aimed at evaluating the potential link between the signal pathways activated in LPS-exposed myocytes and NCX1. In the whole rat heart, LPS perfusion induced an early hypertrophy response during which NCX1 expression significantly increased. Notably, all these changes were completely prevented by the NCX inhibitor SN-6. We further dissect the role of NCX1 in the LPS-induced hypertrophic response in an in vitro cardiac model based on two H9c2 cardiomyoblast clones, namely H9c2-WT (lacking endogenous NCX1 expression) and H9c2-NCX1 (stably transfected with a functional NCX1). H9c2-NCX1 were more susceptible than H9c2-WT to develop a hypertrophic phenotype, and they displayed a significant increase in NCX1 expression and function after LPS treatment. SN-6 completely counteracted both hypertrophic response and exchanger alterations induced by LPS in H9c2-NCX1 cells, but it had no effects on H9c2-WT. Collectively, our results suggest that NCX1 plays a critical role in promoting myocardial hypertrophy triggered by LPS. PMID:25445045

Magi, Simona; Nasti, Annamaria Assunta; Gratteri, Santo; Castaldo, Pasqualina; Bompadre, Stefano; Amoroso, Salvatore; Lariccia, Vincenzo

2015-01-01

9

Immune modulation of the pulmonary hypertensive response to bacterial lipopolysaccharide (endotoxin) in broilers.  

PubMed

The lungs of broilers are constantly challenged with lipopolysaccharide (LPS, endotoxin) that can activate leukocytes and trigger thromboxane A2 (TxA2)- and serotonin (5HT)-mediated pulmonary vasoconstriction leading to pulmonary hypertension. Among broilers from a single genetic line, some individuals respond to LPS with large increases in pulmonary arterial pressure, whereas others fail to exhibit any response to the same supramaximal dose of LPS. This extreme variability in the pulmonary hypertensive response to LPS appears to reflect variability in the types or proportions of chemical mediators released by leukocytes. Our research has confirmed that TxA2 and 5HT are potent pulmonary vasoconstrictors in broilers and that broilers hatched and reared together consistently exhibit pulmonary hypertension after i.v. injections of TxA2 or 5HT. Previous in vitro studies conducted using macrophages from different lines of chickens demonstrated innate variability in the LPS-stimulated induction of nitric oxide synthase (iNOS) followed by the onset of an LPS-refractory state. The NOS enzyme converts arginine to citrulline and nitric oxide (NO). It is known that NO produced by endothelial NOS serves as a key modulator of flow-dependent pulmonary vasodilation, and it is likely that NO generated by iNOS also contributes to the pulmonary vasodilator response. Accordingly, it is our hypothesis that the pulmonary hypertensive response to LPS in broilers is minimal when more vasodilators (NO, prostacyclin) than vasoconstrictors (TxA2, 5HT) are generated during an LPS challenge. Indeed, inhibiting NO production through pharmacological blockade of NOS with the inhibitor Nomega-nitro-L-arginine methyl ester modestly increased the baseline pulmonary arterial pressure and dramatically increased the pulmonary hypertensive response to LPS in all broilers evaluated. Innate differences in the effect of LPS on the pulmonary vasculature may contribute to differences in susceptibility of broilers to pulmonary hypertension syndrome (ascites). PMID:15109060

Wideman, R F; Chapman, M E; Wang, W; Erf, G F

2004-04-01

10

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

SciTech Connect

The objectives were to describe the magnitude and time course of changes in milk pH, Na, K, lactose, and somatic cells and to determine if paracellular pathways were altered after infusion of Escherichia coli endotoxin (serotype 0128:AB12) to produce inflammation in one-half of the udder of the goat. Intramammary infusion of endotoxin increased pH, number of somatic cells, and Na and decreased K and lactose in milk. Sodium and number of somatic cells were increased by as little as .1..mu..g of endotoxin; .25 ..mu..g produced changes in most of the other parameters; maximal effect was elicited by 1..mu..g of endotoxin. The gland response peaked from 5 to 7 h after infusion of endotoxin with an increase in milk cellularity as the only significant effect noted in the control gland. Infusion of (/sup 14/C)lactose into the gland and (/sup 99m/Tc)albumin into the blood demonstrated that large molecules were more able to cross into and out of udder halves after endotoxin treatment. It is suggested that ion interchange rather than bulk flow across paracellular paths is responsible for changes. In addition, endotoxin appeared to reduce lactose secretion and synthesis.

Lengemann, F.W.; Pitzrick, M.

1986-05-01

11

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. PMID:9199453

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

1997-01-01

12

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 ..mu..g 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.

1987-01-01

13

Bacterial lipopolysaccharides form procollagen-endotoxin complexes that trigger cartilage inflammation and degeneration: implications for the development of rheumatoid arthritis  

PubMed Central

Introduction We have previously reported that bacterial toxins, especially endotoxins such as lipopolysaccharides (LPS), might be important causative agents in the pathogenesis of rheumatoid arthritis (RA) in an in vitro model that simulates the potential effects of residing in damp buildings. Since numerous inflammatory processes are linked with the nuclear factor-?B (NF-?B), we investigated in detail the effects of LPS on the NF-?B pathway and the postulated formation of procollagen-endotoxin complexes. Methods An in vitro model of human chondrocytes was used to investigate LPS-mediated inflammatory signaling. Results Immunoelectron microscopy revealed that LPS physically interact with collagen type II in the extracellular matrix (ECM) and anti-collagen type II significantly reduced this interaction. BMS-345541 (a specific inhibitor of I?B kinase (IKK)) or wortmannin (a specific inhibitor of phosphatidylinositol 3-kinase (PI-3K)) inhibited the LPS-induced degradation of the ECM and apoptosis in chondrocytes. This effect was completely inhibited by combining BMS-345541 and wortmannin. Furthermore, BMS-345541 and/or wortmannin suppressed the LPS-induced upregulation of catabolic enzymes that mediate ECM degradation (matrix metalloproteinases-9, -13), cyclooxygenase-2 and apoptosis (activated caspase-3). These proteins are regulated by NF-?B, suggesting that the NF-?B and PI-3K pathways are involved in LPS-induced cartilage degradation. The induction of NF-?B correlated with activation of I?B? kinase, I?B? phosphorylation, I?B? degradation, p65 phosphorylation and p65 nuclear translocation. Further upstream, LPS induced the expression of Toll-like receptor 4 (TLR4) and bound with TLR4, indicating that LPS acts through TLR4. Conclusion These results suggest that molecular associations between LPS/TLR4/collagen type II in chondrocytes upregulate the NF-?B and PI-3K signaling pathways and activate proinflammatory activity. PMID:24020912

2013-01-01

14

Lactoferrin Inhibits the Endotoxin Interaction with CD14 by Competition with the Lipopolysaccharide-Binding Protein  

Microsoft Academic Search

Human lactoferrin (hLf), a glycoprotein released from neutrophil granules during inflammation, and the lipopolysaccharide (LPS)-binding protein (LBP), an acute-phase serum protein, are known to bind to the lipid A of LPS. The LPS-binding sites are located in the N-terminal regions of both proteins, at amino acid residues 28 to 34 of hLf and 91 to 108 of LBP. Both of

ELISABETH ELASS-ROCHARD; DOMINIQUE LEGRAND; VALERIE SALMON; ANCA ROSEANU; MIHAELA TRIF; PETER S. TOBIAS; JOEL MAZURIER; GENEVIEVE SPIK

1998-01-01

15

Murine Monoclonal Antibodies against Escherichia coli O4 Lipopolysaccharide and H5 Flagellin  

PubMed Central

Two murine monoclonal antibodies (MAb), 2C5-F10 and 8D1-H10, reactive with Escherichia coli O4 and H5 antigens, respectively, were generated and characterized. Enzyme immunoassays and immunoblots demonstrated that MAb 2C5-F10 reacted specifically with lipopolysaccharide O antigen of E. coli O4 isolates, while MAb 8D1-H10 reacted with E. coli strains expressing H5 flagella. PMID:11526192

Rivera-Betancourt, Mildred; Keen, James E.

2001-01-01

16

The effects of ACTH, prednisolone and Escherichia coli endotoxin on some clinical haematological and blood biochemical parameters in dwarf goats.  

PubMed

ACTH (microgram kg-1 i.v.) and prednisolone (1 microgram-1 i.v.) caused a moderate but statistically significant inhibition of rumen contractions, whereas no effects on heart rate and body temperature were observed. Both hormones induced hyperglycaemia and leucocytosis, characterised by moderate lymphopenia and a profound increase in the number of circulating neutrophils. A significant decrease in plasma iron and increase in plasma zinc concentrations were observed. After 3 daily i.m. injections of ACTH (10 micrograms-1 day-1) decreases were seen in both serum Alkaline phosphatase (ALP) activity and plasma trace metal concentrations; heart rate was significantly higher. Intraveneous injection of E. coli endotoxin (0.1 microgram kg-1) caused shivering, fever, inhibition of rumen contractions, changes in heart rate, lymphopenia, neutropenia followed by neutrophilic leucocytosis, hypoferraemia, hypozincaemia, hypoglycaemia and a decline in serum ALP activity. ACTH, given i.m. for 3 days, reduced the febrile responses to E. coli endotoxin, modified the changes in heart rate, intensified the inhibition of rumen contractions, and induced a more marked decrease in the number of circulating neutrophils. ACTH pretreatment did not affect the endotoxin-induced decrease in blood glucose concentrations nor the drop in plasma zinc and iron values. These results suggest that glucocorticosteroids are not primarily involved in the fall in plasma iron and zinc concentrations during E. coli endotoxin-induced fever, the effects of endotoxin released glucocorticosteroids on white blood cells and blood glucose are masked by some other effect(s) of endotoxin, and in dwarf goats, ACTH has antipyretic properties without influencing normal body temperature. This effect is probably not dependent on adrenal cortical activity. PMID:3018991

van Miert, A S; van Duin, C T; Wensing, T

1986-07-01

17

GENE EXPRESSION PROFILING OF BOVINE MACROPHAGES IN RESPONSE TO ESCHERICHIA COLI O157:H7 LIPOPOLYSACCHARIDE  

Technology Transfer Automated Retrieval System (TEKTRAN)

The aim of this study was to identify changes in bovine macrophage gene expression in response to treatment with Escherichia coli 0157:H7 lipopolysaccharide (LPS), utilizing a human gene microarray. Bovine cDNA from control and LPS-treated primary macrophages hybridized to greater than 5,644 (79.8%)...

18

Histopathological Study of the Role of CD4- and CD8Positive T Cells on Bone Resorption Induced by Escherichia coli Endotoxin  

Microsoft Academic Search

.   The purpose of this study was to clarify the involvement of CD4+ and CD8+ T cells on bone resorption induced by Escherichia coli endotoxin. Two kinds of monoclonal antibodies, anti-CD4 and\\/or anti-CD8, were employed for the depletion of each or both\\u000a T cell subsets. E. coli endotoxin was injected into mouse mesial gingiva of the first molar of the

Y. Hara; T. Ukai; A. Yoshimura; H. Shiku; I. Kato

1998-01-01

19

The effect of an intramammary infusion of endotoxin on experimentally induced mycoplasmal mastitis.  

PubMed Central

The infusion of 10 microgram of endotoxin lipopolysaccharide from Escherichia coli into the mammary gland of four cows 16 h before inoculation with ureaplasmas did not prevent, or even diminish, the subsequent ureaplasmal mastitis. There was no reduction in the severity or duration of the inflammatory cell response in milk or in the clinical appearance of the resulting mastitis. Also, the excretion of ureaplasmas was not reduced. A similar experiment with Mycoplasma dispar in two cows demonstrated that endotoxin was again ineffective in preventing the mastitis. Furthermore, there was some indication that the proliferation and excretion of this mycoplasma was enhanced in endotoxin-treated quarters. PMID:390046

Brownlie, J.; Howard, C. J.; Gourlay, R. N.

1979-01-01

20

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

2004-01-01

21

Direct effects of E coli endotoxin on structure and permeability of pulmonary endothelial monolayers and the endothelial layer of intimal explants.  

PubMed Central

The direct structural, metabolic, and physiologic effects of Escherichia coli endotoxin on bovine pulmonary endothelial monolayers and on the intact endothelial layer of bovine pulmonary artery intimal explants were examined. Endothelial monolayers exposed to E coli endotoxin (0.001, 0.01, 0.1, 1.0, and 10 micrograms/ml) for 24 hours in the absence of bovine fetal calf serum (FCS) showed a dose-dependent response, as demonstrated by number of pyknotic cells and lactate dehydrogenase release that was enhanced by addition of FCS. Prostacyclin production was increased only in the presence of FCS. Endotoxin also caused an increase in permeability. Endothelial cells on nitrocellulose filters placed in chemotaxis chambers with radioactive tracers in the upper well showed a significant 25% increase in rate of equilibration (counts in lower well/counts in upper well) of 3H-water after 2 and 3 hours' incubation with endotoxin (3 hours' endotoxin = 0.89 +/- 0.03 m +/- SE; no endotoxin = 0.69 +/- 0.05) and a 40% increase in equilibration of 125I-albumin at three hours (3 hours' endotoxin = 0.40 +/- 0.03; no endotoxin = 0.27 +/- 0.02). An increase in hydraulic conductance was also seen at 1 hour. Electron microscopy of the endothelial layer of intimal explants showed dilatations in the intercellular junctions and cellular changes representing contraction--increased prominence of cytoplasmic filaments, nuclear crenation, and cytoplasmic protrusions--at 30 and 60 minutes. From 2 hours evidence of cell death was found. Thus, endotoxin causes structural and metabolic changes in pulmonary endothelial cells and an increase in permeability of the endothelial layer. The injury occurs in the absence of FCS but is enhanced by its addition. Images Figure 2 Figure 8 Figure 10 Figure 11 Figure 12 Figure 13 PMID:3510552

Meyrick, B. O.; Ryan, U. S.; Brigham, K. L.

1986-01-01

22

Enhanced host immune recognition of E.coli causing mastitis in CD-14 transgenic mice.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Escherchia coli causes mastitis, an economically significant disease in dairy animals. E. coli endotoxin (lipopolysaccharide, LPS) when bound by host membrane proteins such as CD-14, causes release of pro-inflammatory cytokines recruiting neutrophils as a early innate immune response. Excessive pr...

23

Tumor necrosis factor-alpha and nitrite/nitrate responses during acute mastitis induced by Escherichia coli infection and endotoxin in dairy cows.  

PubMed

Concentrations of tumor necrosis factor-alpha (TNF-alpha) and of NO(x) (sum of nitrite and nitrate as indicators of endogenous nitric oxide production) in milk and blood plasma were measured in three mastitis models in dairy cows in early lactation. Escherichia coli P4:O37 bacteria or endotoxin O111:B4 were administered into both left quarters of 12 and 6 cows, respectively. Six of the E. coli-infected cows were treated with a bactericidal antibiotic (Enrofloxacin; Bayer AG, Leverkusen, Germany) i.v. at 10 hr and subcutaneously (sc) at 30 hr after infection. NO(x) concentrations transiently increased maximally 10- to 11-fold in milk of E. coli-infected quarters with or without antibiotic treatment at 24 hr and after endotoxin administration. NO(x) concentrations did not change in milk of unchallenged quarters and in blood plasma. Increases of NO(x) were proceeded by a transient (96- to 149-fold) rise of milk TNF-alpha concentrations, which in endotoxin-administered quarters was maximal at 6 hr and in infected quarters without or with Enrofloxacin treatment at 10 and 14 hr. In blood plasma TNF-alpha concentrations only moderately increased to peaks in endotoxin-administered cows at 6 hr and in E. coli-infected cows at 14 hr postchallenge. In one severely sick, nontreated E. coli-infected cow milk, TNF-alpha response at 14 hr was excessive and followed by a spectacular rise of NO(x) concentration in milk between 48 and 72 hr. In conclusion, a possible clinical relevance of nitric oxide production associated with a rise of intramammary and systemic TNF-alpha during acute mastitis by E. coli infection and endotoxin in lactating dairy cows is indicated, but could not be inhibited by antibiotic treatment. PMID:11118787

Blum, J W; Dosogne, H; Hoeben, D; Vangroenweghe, F; Hammon, H M; Bruckmaier, R M; Burvenich, C

2000-11-01

24

Evidence of persisting serum antibodies to Escherichia coli O157 lipopolysaccharide and Verocytotoxin in members of rural communities in England  

Microsoft Academic Search

The techniques of enzyme-linked immunosorbent assay (ELISA) and immunoblotting were used to examine a total of 1667 sera, from apparently healthy members of rural communities in England, for antibodies to the lipopolysaccharide (LPS) of Escherichia coli O157 and Verocytotoxins (VT). Twenty-nine sera from 22 individuals were shown to have antibodies specific for E. coli O157 LPS. Some of these lived

J. Evans; R. M. Chalmers; H. Chart; R. L. Salmon; S. M. Kench; T. J. Coleman; D. Meadows; P. Morgan-Capner; P. Softley; M. Sillis; D. Rh. Thomas

2000-01-01

25

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. PMID:21318186

Geens, Marisa M.; Niewold, Theo A.

2010-01-01

26

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: shliu@ha.mc.ntu.edu.tw

2005-10-15

27

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

PubMed

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

2012-08-01

28

Crystallization of R-form lipopolysaccharides from Salmonella minnesota and Escherichia coli.  

PubMed Central

Salmonella minnesota Re and Ra lipopolysaccharides (LPSs) and Escherichia coli K-12 LPS formed three-dimensional crystals, either hexagonal plates (preferential growth along the a axis) or solid columns (preferential growth along the c axis), when they were precipitated by the addition of 2 volumes of 95% ethanol containing 375 mM MgCl2 and incubated in 70% ethanol containing 250 mM MgCl2 at 4 degrees C for 10 days. Analyses of crystals suggested that they consist of hexagonal lattices with the a axis (a side of the lozenge as a unit cell on the basal plane) of 0.462 nm for all these three kinds of LPSs and the c axes (perpendicular to the basal plane) of 5.85, 8.47, and 8.75 nm for S. minnesota Re and Ra LPSs and E. coli K-12 LPS, respectively, and that hydrocarbon chains of the lipid A portion play the leading part in crystallization, whereas the hydrophilic part of the lipid A (the disaccharide backbone) and R core exhibit a disordered structure or are in a random orientation. The phenomenon of doubling of the a axis to 0.924 nm was observed with crystals of S. minnesota Re LPS when they were incubated in 70% ethanol for an additional 180 days, but not with crystals of S. minnesota Ra LPS or E. coli K-12 LPS. S. minnesota S-form LPS possessing the O-antigen-specific polysaccharide and S. minnesota free lipid A obtained by acid hydrolysis of Re LPS did not crystallize under the same experimental conditions. Images FIG. 1 FIG. 2 FIG. 3A-3B FIG. 3C FIG. 4 PMID:2407725

Kato, N; Ohta, M; Kido, N; Ito, H; Naito, S; Hasegawa, T; Watabe, T; Sasaki, K

1990-01-01

29

Effects of tilorone hydrochloride on cellular immunity (leukocyte inhibiting factor production from human lymphocyte stimulated by E. coli lipopolysaccharide).  

PubMed

Tilorone hydrochloride, a drug able selectively to affect T-lymphocyte fuction, when incorporated (at three different concentrations 0.1, 0.04, 0.02 microgram/ml) in lymphocyte culture, stimulated by 50 microgram/ml of E. coli LPS (026:B6 W), is able to abolish LIF production, due to endotoxin stimulation. Such effect is, may be, due to an impairment of T-cell activity, since tilorone at the same concentration decreases the number of ARFC and TRFC, which are specific markers for T-cells. PMID:334193

Jirillo, E; Monno, R; Munno, I; De Santis, A; Fumarola, D

1977-09-01

30

Expression of lipopolysaccharide O antigen in Escherichia coli K-12 hybrids containing plasmid and chromosomal genes from Shigella dysenteriae 1.  

PubMed Central

The requirement for both plasmid and chromosomal genes in the biosynthesis of Shigella dysenteriae 1 lipopolysaccharide O antigen was demonstrated in Escherichia coli-Shigella hybrids. A 6-megadalton S. dysenteriae 1 plasmid, designated pWR23, was phenotypically tagged with the Tn3 ampicillin-resistance transposon. The tagged plasmid, designated pWR24, was transferred by transformation or conjugal mobilization to a rough E. coli K-12 recipient. Although the resultant hybrids were agglutinated in S. dysenteriae 1 antiserum, they did not remove all of the anti-Shiga agglutinins in absorption experiments. Modified lipid A core structure was detected in these hybrids, but Shiga O antigen was not expressed. When the his+ locus of the S. dysenteriae 1 chromosome was transferred by transduction to E. coli K-12 containing pWR24, complete Shiga O antigen was expressed. Lipopolysaccharide extracted from these hybrids was indistinguishable chemically, electrophoretically, and serologically from native S. dysenteriae 1 lipopolysaccharide. Images PMID:6389345

Hale, T L; Guerry, P; Seid, R C; Kapfer, C; Wingfield, M E; Reaves, C B; Baron, L S; Formal, S B

1984-01-01

31

Lipopolysaccharide is transferred from high-density to low-density lipoproteins by lipopolysaccharide-binding protein and phospholipid transfer protein  

Microsoft Academic Search

Lipopolysaccharide (LPS), the major outer membrane component of gram-negative bacteria, is a potent endotoxin that triggers cytokine-mediated systemic inflammatory responses in the host. Plasma lipoproteins are capable of LPS sequestration, thereby attenuating the host response to infection, but ensuing dyslipidemia severely compromises this host defense mechanism. We have recently reported that Escherichia coli J5 and Re595 LPS chemotypes that contain

J. A. Marquart; P. R. Abraham; Ende van den A. E; H. O. F. Molhuizen; Deventer van S. J. H; J. C. M. Meijers

2005-01-01

32

In vitro evaluation of the action of irrigating solutions associated with intracanal medications on Escherichia coli and its endotoxin in root canals  

PubMed Central

Objective The purpose of this study was to evaluate the efficacy of auxiliary chemical substances and intracanal medications on Escherichia coli and its endotoxin in root canals. Material and Methods Teeth were contaminated with a suspension of E. coli for 14 days and divided into 3 groups according to the auxiliary chemical substance used: G1) 2.5% sodium hypochlorite (NaOCl); G2) 2% chlorhexidine gel (CLX); G3) pyrogen-free solution. After, these groups were subdivided according to the intracanal medication (ICM): A) Calcium hydroxide paste (Calen®), B) polymyxin B, and C) Calcium hydroxide paste+2% CLX gel. For the control group (G4), pyrogen-free saline solution was used without application of intracanal medication. Samples of the root canal content were collected immediately after biomechanical preparation (BMP), at 7 days after BMP, after 14 days of intracanal medication activity, and 7 days after removal of intracanal medication. The following aspects were evaluated for all collections: a) antimicrobial activity; b) quantification of endotoxin by the Limulus Amebocyte Lysate test (LAL). Results were analyzed by the Kruskal-Wallis and Dunn’s tests at 5% significance level. Results The 2.5% NaOCl and CLX were able to eliminate E. coli from root canal lumen and reduced the amount of endotoxin compared to saline. Conclusions It was concluded that 2.5% NaOCl and CLX were effective in eliminating E. coli. Only the studied intracanal medications were to reduce the amount of endotoxin present in the root canals, regardless of the irrigant used. PMID:21552710

MAEKAWA, Lilian Eiko; VALERA, Marcia Carneiro; de OLIVEIRA, Luciane Dias; CARVALHO, Cláudio Antonio Talge; KOGA-ITO, Cristiane Yumi; JORGE, Antonio Olavo Cardoso

2011-01-01

33

Extraction, Purification and Characterization of Lipopolysaccharide from Escherichia coli and Salmonella typhi  

PubMed Central

Lipopolysaccharide (LPS) is an important structural component of the outer cell membrane complex of gram negative microorganisms. Its causative role in gram negative bacteria-induced diseases and broad applications in different kinds of cell stimulation experiments provided a conceptual basis for studies directed at the isolation, purification, and detailed chemical characterization of LPS. The main problem with LPS purification protocols is the contamination of the end product with nucleic acids and proteins in variable proportions which could potentially interfere with downstream applications. In this study, a simple procedure for purification of LPS from Escherichia coli (E.coli) and Salmonella typhi (S.typhi) with high purity and very low contaminating nucleic acids and proteins based on the hot phenol-water extraction protocol has been introduced. The purity of extracted LPS was evaluated by silver and coomassie blue staining of SDS-PAGE gels and HPLC analysis. Limulus Amebocyte Lysate (LAL) coagulation activity and rabbit pyrogen assay were exploited to monitor the functionality of purified LPS. The results showed that DNase and RNase treatment of the sample is essential after the sonication step to eliminate nucleic acid contamination in the LPS fraction. Silver staining demonstrated ladder pattern which is characteristic of LPS. No contaminating protein was found as assessed by coomassie blue staining. HPLC fractionation revealed high degree of purity comparable with commercial LPS. Parenteral administration of purified LPS resulted in substantial increase of rabbits’ body temperature (mean: 1.45°C). LAL coagulation assay confirmed the functional activity of the purified LPS. In conclusion, the protocol presented here could be employed for isolation of LPS with high purity and functional activity. PMID:23407691

Rezania, Simin; Amirmozaffari, Noor; Tabarraei, Bahman; Jeddi-Tehrani, Mahmood; Zarei, Omid; Alizadeh, Reza; Masjedian, Faramarz; Zarnani, Amir Hassan

2011-01-01

34

A mutant Escherichia coli that attaches peptidoglycan to lipopolysaccharide and displays cell wall on its surface  

PubMed Central

The lipopolysaccharide (LPS) forms the surface-exposed leaflet of the outer membrane (OM) of Gram-negative bacteria, an organelle that shields the underlying peptidoglycan (PG) cell wall. Both LPS and PG are essential cell envelope components that are synthesized independently and assembled by dedicated transenvelope multiprotein complexes. We have identified a point-mutation in the gene for O-antigen ligase (WaaL) in Escherichia coli that causes LPS to be modified with PG subunits, intersecting these two pathways. Synthesis of the PG-modified LPS (LPS*) requires ready access to the small PG precursor pool but does not weaken cell wall integrity, challenging models of precursor sequestration at PG assembly machinery. LPS* is efficiently transported to the cell surface without impairing OM function. Because LPS* contains the canonical vancomycin binding site, these surface-exposed molecules confer increased vancomycin-resistance by functioning as molecular decoys that titrate the antibiotic away from its intracellular target. This unexpected LPS glycosylation fuses two potent pathogen-associated molecular patterns (PAMPs). DOI: http://dx.doi.org/10.7554/eLife.05334.001 PMID:25551294

Grabowicz, Marcin; Andres, Dorothee; Lebar, Matthew D; Maloj?i?, Goran; Kahne, Daniel; Silhavy, Thomas J

2014-01-01

35

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

PubMed

The mycotoxin deoxynivalenol (DON) and lipopolysaccharides (LPS) are reported to act synergistically in the animal organism. Thus, we tested the hypothesis that systemic co-exposure of DON and LPS aggravates the impact of the individual toxin on leukocyte counts in vivo and peripheral blood mononuclear cells (PBMC) ex vivo. Growing barrows were fed a standard diet, equipped with permanent venous catheters and infused for 1 h with one of four treatments: control group with physiological saline (CON, n?=?8), mycotoxin group (DON, n?=?6) with 100 ?g/kg body weight (BW) deoxynivalenol, endotoxin group (LPS, n?=?6) with 7.5 ?g/kg BW Escherichia coli LPS, and co-exposed group (DON?+?LPS, n?=?6) with 100 ?g/kg BW DON and 7.5 ?g/kg BW LPS. Blood was collected 30 min prior to infusion and 10, 20, 30, 60, 360, 720 and 1440 min after start of infusion for total and differential leukocyte counts. PBMC were isolated from blood drawn at 3 and 24 h and subjected to an ex vivo 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay, either non-stimulated or stimulated with concanavalin A. LPS induced a transient significant leukopenia between 30 and 360 min, owing to a decrease in segmented neutrophils and lymphocytes (time?×?treatment: p?

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

2015-02-01

36

Methods of Endotoxin Removal from Biological Preparations: a Review  

Microsoft Academic Search

PURPOSE: Endotoxins, also called lipopolysaccharides (LPS), are major contaminants found in commercially available proteins or biologically active substances, which often complicate study of the biological effects of the main ingredient. The presence of small amounts of endotoxin in recombinant protein preparations can cause side effects in host organism such as endotoxin shock, tissue injury, and even death. Due to these

Pérola O. Magalhăes; André M. Lopes; Priscila G. Mazzola; Carlota Rangel-Yagui; Thereza C. V. Penna; Adalberto Pessoa Jr

2007-01-01

37

Anti-inflammatory effects of Podophyllum hexandrum (RP1) against lipopolysaccharides induced inflammation in mice  

Microsoft Academic Search

PURPOSE: Down-regulation of lipopolysaccharide (LPS) induced hyper-inflammatory response by non-toxic pharmacological agents acquires paramount importance for countering bacterial sepsis. Anti-inflammatory potential of aqueous extract of Podophyllum hexandrum, a plant well documented in Ayurvedic literature for various therapeutic purposes, was investigated. METHODS: In vivo studies were performed on Balb\\/c mice pre-treated with supra- lethal dose of LPS endotoxin (E.coli 055:B5) with

Hridayesh Prakash; Arif Ali

38

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. PMID:3322954

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

1987-01-01

39

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

PubMed Central

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

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

2014-01-01

40

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

PubMed Central

Lipopolysaccharide (LPS) is a major constituent of the outer membrane of gram-negative bacteria that serves as a barrier against harmful molecules, including antibiotics. The waaYZ locus that encodes the LPS core biosynthetic function in Escherichia coli was found to be induced strongly by superoxide generators but not by H2O2, ethanol, or heat shock. This induction was dependent on SoxRS, a superoxide and nitric oxide sensing system, through a soxbox in the waaY promoter that binds SoxS. A ?waaYZ mutant became more sensitive to some superoxide generators, and the activation of SoxR by these drugs became more sensitized in the mutant. Through phenotypic microarray analysis, we found that the mutant became sensitive to a wide variety of chemicals not restricted to oxidizing agents. We found that the mutant is under envelope stress and is altered in LPS composition, as monitored by the level of ?E activation and changes in the electrophoretic mobility of LPS, respectively. waaY expression was also regulated by MarA (multiple-antibiotic resistance regulator), which shares a binding site (soxbox) with SoxS, and was induced by salicylate, a nonoxidative compound. These results demonstrate a novel way of protecting gram-negative bacteria against various compounds by modifying LPS, possibly through phosphorylation. Since either oxidant or nonoxidant compounds elicit resistance toward themselves and other toxic drugs, this mechanism could serve as an efficient way for pathogenic bacteria to enhance survival during antibiotic treatment within an oxidant-rich host immune environment. PMID:19376854

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

2009-01-01

41

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

PubMed Central

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 1H,1H-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

2013-01-01

42

Extraction of cyanobacterial endotoxin.  

PubMed

To simplify our efforts in acquiring toxicological information on endotoxins produced by cyanobacteria, a method development study was undertaken to identify relatively hazard-free and efficient procedures for their extraction. One article sourced and two novel methods were evaluated for their ability to extract lipopolysaccharides (LPSs) or endotoxins from cyanobacteria. The Limulus polyphemus amoebocyte lysate (LAL) assay was employed to compare the performance of a novel method utilizing a 1-butanol-water (HBW) solvent system to that of Westphal's (1965) phenol-water system (HPW) for the extraction of endotoxin from various cyanobacteria. The traditional HPW method extracted from 3- to 12-fold more endotoxin from six different cyanobacterial blooms and culture materials than did the novel HBW method. In direct contrast, the novel HBW method extracted ninefold more endotoxin from a non-microcystin producing Microcystis aeruginosa culture as compared to the HPW method. A solvent system utilizing N,N'-dimethylformamide-water (HDW) was compared to both the HPW and HBW methods for the extraction of endotoxin from natural samples of Anabaena circinalis, Microcystis flos-aquae, and a 1:1 mixture of Microcystis aeruginosa/Microcystisflos-aquae. The LAL activities of these extracts showed that the novel HDW method extracted two- and threefold more endotoxin from the Anabaena sample that did the HBW and HPW methods, respectively. The HDW method also extracted approximately 1.5-fold more endotoxin from the Microcystis flos-aquae sample as compared to both the HBW and HPW methods. On the other hand, the HBW method extracted 2- and 14-fold more endotoxin from the Microcystis flos-aquae/Microcystis aeruginosa mixture than did the HPW and HDW methods, respectively. Results of this study demonstrate that significant disparities exist between the physicochemical properties of the cell wall constituents not only of different cyanobacterial species but also of different strains of the same cyanobacterial species, as showing by the varying effectiveness of the solvent systems investigated. Therefore, a sole method cannot be regarded as universal and superior for the extraction of endotoxins from cyanobacteria. Nevertheless, the ability of the novel HBW and HDW methods to utilize easily handled organic solvents that are less hazardous than phenol render them attractive alternatives to the standard HPW method. PMID:14758595

Papageorgiou, John; Linke, Thomas A; Kapralos, Con; Nicholson, Brenton C; Steffensen, Dennis A

2004-02-01

43

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

PubMed Central

The natural switch from fever to hypothermia observed in the most severe cases of systemic inflammation is a phenomenon that continues to puzzle clinicians and scientists. The present study was the first to evaluate in direct experiments how the development of hypothermia vs. fever during severe forms of systemic inflammation impacts the pathophysiology of this malady and mortality rates in rats. Following administration of bacterial lipopolysaccharide (LPS; 5 or 18 mg/kg) or of a clinical Escherichia coli isolate (5 × 109 or 1 × 1010 CFU/kg), hypothermia developed in rats exposed to a mildly cool environment, but not in rats exposed to a warm environment; only fever was revealed in the warm environment. Development of hypothermia instead of fever suppressed endotoxemia in E. coli-infected rats, but not in LPS-injected rats. The infiltration of the lungs by neutrophils was similarly suppressed in E. coli-infected rats of the hypothermic group. These potentially beneficial effects came with costs, as hypothermia increased bacterial burden in the liver. Furthermore, the hypotensive responses to LPS or E. coli were exaggerated in rats of the hypothermic group. This exaggeration, however, occurred independently of changes in inflammatory cytokines and prostaglandins. Despite possible costs, development of hypothermia lessened abdominal organ dysfunction and reduced overall mortality rates in both the E. coli and LPS models. By demonstrating that naturally occurring hypothermia is more advantageous than fever in severe forms of aseptic (LPS-induced) or septic (E. coli-induced) systemic inflammation, this study provides new grounds for the management of this deadly condition. PMID:22513748

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

2012-01-01

44

Structural analysis of oligosaccharides from lipopolysaccharide (LPS) of Escherichia coli K12 strain W3100 reveals a link between inner and outer core LPS biosynthesis.  

PubMed

Lipopolysaccharide (LPS) from Escherichia coli K12 W3100 is known to contain several glycoforms, and the basic structure has been investigated previously by methylation analyses (Holst, O. (1999) in Endotoxin in Health and Disease (Brade, H., Opal, S. M., Vogel, S. N., and Morrison, D., eds) pp. 115-154; Marcel Dekker, Inc., New York). In order to reveal dependences of gene activity and LPS structure, we have now determined the composition of de-O-acylated LPS by electrospray ionization-Fourier transform ion cyclotron-mass spectrometry (ESI-FT-MS) and identified 11 different LPS molecules. We have isolated the major glycoforms after de-O- and de-N-acylation and obtained four oligosaccharides that differed in their carbohydrate structure and phosphate substitution. The main oligosaccharide accounted for approximately 70% of the total and had a molecular mass of 2516 Da according to ESI-FT-MS. The dodecasaccharide structure (glycoform I) as determined by NMR was consistent with MS and compositional analysis. One minor oligosaccharide (5%) of the same carbohydrate structure did not contain the 4'-phosphate of the lipid A. Two oligosaccharides contained the same phosphate substitution but differed in their carbohydrate structure, one (5%) which contained an additional beta-D-GlcN in 1-->7 linkage on a terminal heptose residue (glycoform II) which was N-acetylated in LPS. A minor amount of a molecule lacking the terminal L-alpha-D-Hep in the outer core but otherwise identical to the major oligosaccharide (glycoform III) could only be identified by ESI-FT-MS of the de-O-acylated LPS. The other oligosaccharide (20%) contained an alpha-Kdo-(2-->4)-[alpha-l-Rha-(1-->5)]-alpha-Kdo-(2-->4)-alpha-Kdo branched tetrasaccharide connected to the lipid A (glycoform IV). This novel inner core structure was accompanied by a truncation of the outer core in which the terminal disaccharide L-alpha-D-Hep-(1-->6)-alpha-D-Glc was missing. The latter structure was identified for the first time in LPS and revealed that changes in the inner core structure may be accompanied by structural changes in the outer core. PMID:12819207

Müller-Loennies, Sven; Lindner, Buko; Brade, Helmut

2003-09-01

45

Recent advances in biosensor based endotoxin detection.  

PubMed

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

2014-01-15

46

Production of the Acute-Phase Protein Lipopolysaccharide-Binding Protein by Respiratory Type II Epithelial Cells Implications for Local Defense to Bacterial Endotoxins  

Microsoft Academic Search

This study demonstrates for the first time that respiratory epi- thelial cells are able to produce the acute phase protein lipopolysaccharide (LPS)-binding protein (LBP), which is known to play a central role in the defense to bacterial endo- toxins (or LPS). Indications for local presence of LBP in human lung was obtained via reverse transcriptase\\/polymerase chain reaction that showed LBP

Mieke A. Dentener; Anita C. E. Vreugdenhil; Peter H. M. Hoet; Juanita H. J. Vernooy; Fred H. M. Nieman; Didier Heumann; Yvonne M. W. Janssen; Wim A. Buurman; Emiel F. M. Wouters

47

Neutralization of bacterial lipopolysaccharides by human plasma.  

PubMed Central

To quantify the neutralization of bacterial lipopolysaccharide (LPS) by human plasma, dilutions of Escherichia coli O113 LPS were incubated with plasma, followed by the addition of Limulus amebocyte lysate (LAL). The reaction between the LPS and LAL was monitored spectrophotometrically, and the concentration of LPS resulting in 50% lysate response (LR50) was determined. Analysis of 145 outdated plasma samples yielded a range of LR50 between 6 and 1,500 ng/ml. Pools of plasma with high and low LR50 were prepared. The pool with high LR50 neutralized 166-fold more E. coli 0113 LPS, 190-fold more E. coli 0111B4 LPS, 42-fold more Klebsiella pneumoniae LPS, and 29-fold more Salmonella typhimurium LPS than did the pool with low LR50. Each pool had similar immunoglobulin G (IgG) and IgM antibody levels to homologous LPS, measured by an enzyme-linked immunosorbent assay. Analysis of 212 fresh-frozen plasma units revealed a range of LR50 between 48 and 6,000 ng/ml. Incubation of LPS in a pool of fresh-frozen plasma with high LR50 elicited significantly less fever in the rabbit pyrogen test than did LPS incubated in plasma with low LR50 (fever index, 2.68 +/- 0.61 degrees C X h and 3.52 +/- 0.66 degrees C X h, respectively; P = 0.003). We conclude that there is a 100-fold range in the endotoxin-neutralizing capacity of human plasma and that this variation is not due to LPS-specific IgG or IgM antibodies. Further investigations are needed to determine whether differing susceptibility of patients to the effects of LPS is due to differences in the endotoxin-neutralizing capacity of their plasma and whether plasma screened for high endotoxin-neutralizing capacity may be therapeutically useful in endotoxemia. PMID:3908471

Warren, H S; Novitsky, T J; Ketchum, P A; Roslansky, P F; Kania, S; Siber, G R

1985-01-01

48

ENDOTOXINS, ALGAE AND 'LIMULUS' AMOEBOCYTE LYSATE TEST IN DRINKING WATER  

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 ...

49

Genes for TDP-rhamnose synthesis affect the pattern of lipopolysaccharide heterogeneity in Escherichia coli K-12.  

PubMed Central

The rough lipopolysaccharide (LPS) of commonly used strains of Escherichia coli K-12 has two distinctly different band patterns when analyzed by high-resolution polyacrylamide gel electrophoresis. The LPS of ancestral strains such as W1485F- consists primarily of a single broad gel band. In contrast, the LPS of strains derived from strain Y10 such as AB1133 or C600 gives three sharp gel bands. Complementation studies using DNA fragments from the rfb gene cluster of Shigella dysenteriae 1 indicated that the difference between the two gel patterns is due to a mutation in the gene encoding the TDP-rhamnose synthetase, the final enzyme involved in TDP-rhamnose biosynthesis. This mutation arose during the construction of strain Y10, and not in strain 679-680 as previously thought. The requirement for the rfaS gene for synthesis of the broad major band seen in W1485F- LPS and the shift in gel migration of a component of this band when an rfaQ mutation was introduced indicated that this broad band contained the unique form of rough E. coli LPS which has been termed lipooligosaccharide. This finding indicates that lipooligosaccharide is likely to contain rhamnose and suggests a model in which one of the functions of partial substituents such as rhamnose may be to direct core synthesis into different pathways to produce alternative forms of LPS. Images PMID:7517388

Klena, J D; Schnaitman, C A

1994-01-01

50

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

PubMed

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

2009-12-01

51

Elimination of endotoxin from the blood by extracorporeal activated charcoal hemoperfusion in experimental canine endotoxin shock.  

PubMed

Circulating endotoxin is an important factor in the pathogenesis and clinical symptoms of endotoxin shock. The effect of extracorporeal activated charcoal hemoperfusion was investigated in experimental endotoxin shock of dogs produced by i.v. injection of Escherichia coli 089 endotoxin (1 mg/kg body weight). The endotoxin was labeled with 99mTc. The aorta and vein cava caudalis of anesthetized dogs were cannulated through the arteria and vein femorales. The cannulae were contacted to the hemoperfusion charcoal cartridge. The efficiency of hemoperfusion was tested from the blood samples, and the endotoxin content of blood was measured biologically (in lead acetate-treated rats) and isotopically (99mTc radioactivity) at 15, 30, 60, 90, and 120 min after injection. It was demonstrated that extracorporeal activated charcoal hemoperfusion can eliminate the majority of circulating endotoxin from the blood within 30 min. PMID:3719924

Bende, S; Bertók, L

1986-01-01

52

Polymyxin B suppresses the endotoxin inhibition of concanavalin a-mediated erythrocyte agglutination.  

PubMed Central

The lectin agglutinability of human erythrocytes has been utilized to examine interactions of gram-negative endotoxin with mammalian cell plasma membranes. Erythrocytes treated in buffer with Escherichia coli 0127:B8 lipopolysaccharide (LPS) or Salmonella minnesota Re595 glycolipid for 1 h became resistant to agglutination by the lectin concanavalin A (ConA) in buffer free of LPS or glycolipid. Polymyxin B, a cationic cyclic lipopeptide which specifically binds to the lipid A toxophore, was tested for possible effects on the LPS and glycolipid inhibition of Con A erythrocyte agglutination. The presence of polymyxin B during the initial 1-h treatment with LPS or glycolipid blocked the ability of the endotoxins to render erythrocytes refractory to agglutination by ConA. Inhibition by polymyxin B was stoichiometric, and in repeated experiments, LPS was completely suppressed in the hemagglutination assay at a polymyxin B:LPS weight ratio of 1:4.1 (increasing polymyxin concentration, constant LPS concentration) and 1:5.1 (constant polymyxin concentration, increasing LPS concentration). These stoichiometry values are similar to values obtained for inhibition by polymyxin B of LPS lymphoid cell activation. It was concluded, therefore, that endotoxin inhibition of ConA erythrocyte agglutination reflects interactions of erythrocyte membranes with the lipid A region of endotoxin. In addition, the stoichiometry of polymyxin B inhibition suggests a similar extent of lipid A-dependent LPS interaction with erythrocytes and lymphoid cells. PMID:6276306

Warren, J R

1982-01-01

53

Endotoxin removal by radio frequency gas plasma (glow discharge)  

NASA Astrophysics Data System (ADS)

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

Poon, Angela

2011-12-01

54

[Shigella endotoxin protein--its electrophoretic and serological properties].  

PubMed

The electrophoretic analysis of lipid A-associated protein (LAP), obtained from S. sonnei, in polyacrylamide gel in the presence of sodium dodecyl sulfate and urea has revealed the heterogeneity of the preparation; it has found to contain three main components with molecular weights of 43, 38 and 18 KD and some minor components with molecular weights of 49, 45 35, 30, 29, 27, 5, 21 and 14 KD. The electrophoretic mobility of the main protein components in the isolated preparation of LAP coincides with that of endotoxin components. The dissociation of proteins and lipopolysaccharide in the process of boiling the endotoxin in 2% sodium dodecyl sulfate is indicative of the noncovalent binding of these components. LAP contained in the endotoxin, in contrast to isolated LAP, is resistant to trypsin and proteinase K. The enzyme immunoassay (EIA) system with the use of LAP as a component of its solid phase has been developed, which makes it possible to carry out the quantitative determination of antibodies to this protein. The EIA system shows high sensitivity in the determination of anti-LAP IgG antibodies: in hyperimmune rabbit sera their titer is 1:250,000-1:800,000. As shown by the method of competitive EIA, the antigenic affinity of LAP of different origin corresponds to the degree of taxonomic propinquity of microorganisms: the maximal degree of cross reactions is observed between LAP obtained from S. sonnei, S. flexneri and Escherichia coli, while their affinity to Salmonella typhi is considerably less; remote microbial species (Bacterium bifidum and Sarcina marcescens) give practically no cross reactions. PMID:1882599

Nartikova, V F; Egorova, T P; Belkin, Z P; Fedosova, V G; Levenson, V I

1991-04-01

55

Effect of lipopolysaccharide (LPS) chain length on interactions of bactericidal/permeability-increasing protein and its bioactive 23-kilodalton NH2-terminal fragment with isolated LPS and intact Proteus mirabilis and Escherichia coli.  

PubMed Central

The target-specific cytotoxicity for gram-negative bacteria and the endotoxin-neutralizing activity of the 55-kDa bactericidal/Permeability-increasing protein (BPI) and its bioactive 23-kDa NH2-terminal fragment depend on the strong attraction of BPI for the lipid A region of lipopolysaccharides (LPS). We have shown before that smooth gram-negative bacteria with long-chain LPS are more resistant to BPI (especially holo-BPI) than are rough strains. It has been suggested that the high BPI resistance of some gram-negative bacteria, such as Proteus mirabilis, might also reflect the structural diversity of lipid A. To explore this possibility, we compared the antibacterial activity and binding of natural and recombinant holo-BPI and a recombinant NH2-terminal fragment (rBPI-23) to an isogenic rough (Re-LPS chemotype) and a smooth (S-LPS chemotype) strain of P. mirabilis and to LPS isolated from the two strains. Holo-BPI and rBPI-23 were both potently active against the Re strain of P. mirabilis (90% lethal dose, 20 nM). In contrast, the smooth strain was > or = 100 times more resistant to holo-BPI but only 10 times more resistant to rBPI-23. rBPI-23 was also more potent against several Escherichia coli strains from clinical bacteremia isolates. Differences in the antibacterial potency of BPI toward the Re and S strains of P. mirabilis correlated with differences in the binding of holo-BPI and rBPI-23 to these bacteria. In contrast, the binding of biosynthetically (in vitro transcribed and translated) 35S-labeled holo-BPI and NH2-terminal fragment to isolated Re- and S-LPS from P. mirabilis in solution was similar. Moreover, in the Limulus amebocyte lysate assay, holo-BPI and rBPI-23 potently neutralized both forms of LPS with equal effectiveness. Together, these results strongly suggest that BPI recognizes Proteus lipid A and that the relative resistance of (smooth) P. mirabilis to holo-BPI is due to the inhibitory effect of long polysaccharide chains of tightly packed LPS in the envelope. Images PMID:8262637

Capodici, C; Chen, S; Sidorczyk, Z; Elsbach, P; Weiss, J

1994-01-01

56

Functional Analysis of the Protein Machinery Required for Transport of Lipopolysaccharide to the Outer Membrane of Escherichia coli  

Microsoft Academic Search

Lipopolysaccharide (LPS) is an essential component of the outer membrane (OM) in most gram-negative bacteria, and its structure and biosynthetic pathway are well known. Nevertheless, the mechanisms of trans- port and assembly of this molecule at the cell surface are poorly understood. The inner membrane (IM) transport protein MsbA is responsible for flipping LPS across the IM. Additional components of

Paola Sperandeo; Fion K. Lau; Andrea Carpentieri; Cristina De Castro; Antonio Molinaro; Gianni Deho; Thomas J. Silhavy; Alessandra Polissi

2008-01-01

57

Biological Characterization of Lipopolysaccharide from Treponema pectinovorum  

PubMed Central

This study investigated the endotoxic and biological properties of purified lipopolysaccharide (LPS) isolated from an oral spirochete, Treponema pectinovorum. Endotoxicity, measured by Limulus amoebocyte lysate kinetic assay, showed that the LPS contained 1.28 endotoxin units per ?g of purified LPS, which was approximately 4,000 times less than Escherichia coli O55:B5 LPS. To determine in vivo endotoxicity, LPS responder mice were administered LPS following galactosamine (GalN) sensitization. The LPS induced neither endotoxic symptoms nor lethality for 96 h, suggesting negligible or very low endotoxicity. In contrast, infection with live T. pectinovorum induced 100% lethality within 12 h in GalN-sensitized LPS responder mice, indicating an endotoxin-like property of this treponeme. Heat-killed microorganisms exhibited no lethality in GalN-sensitized mice, suggesting that the endotoxicity was associated with heat-labile components. To determine cytokine and chemokine induction by LPS, human gingival fibroblasts were stimulated and secretion of interleukin 1? (IL-1?), granulocyte-macrophage colony-stimulating factor, gamma interferon, IL-6, IL-8, and monocyte chemoattractant protein 1 (MCP-1) was assessed. The purified LPS induced significant amounts of only IL-6, IL-8, and MCP-1, although they were substantially lower than levels after challenge with live T. pectinovorum. After injection of LPS or live or heat-killed T. pectinovorum, serum was collected from mice and analyzed for proinflammatory cytokines IL-1?, tumor necrosis factor alpha (TNF-?), and IL-6. LPS induced only IL-6 consistently. Both live and heat-killed T. pectinovorum induced serum IL-6, which was higher than the level detected following LPS administration. Importantly, live bacteria elicited systemic TNF-? and IL-1? levels similar to those induced by a lethal dose of live E. coli O111. The results indicated that T. pectinovorum LPS has very low or no endotoxicity, although it can elicit low levels of cytokines from host cells. In contrast to the LPS, live T. pectinovorum demonstrated in vivo toxicity, which was associated with serum IL-1?, TNF-?, and IL-6, suggesting an endotoxin-like property of a heat-labile molecule(s) of the spirochete. PMID:11748185

Kesavalu, Lakshmyya; Falk, Clinton W.; Davis, Kenneth J.; Steffen, Michelle J.; Xu, Xiaoping; Holt, Stanley C.; Ebersole, Jeffrey L.

2002-01-01

58

FtsH-Mediated Coordination of Lipopolysaccharide Biosynthesis in Escherichia coli Correlates with the Growth Rate and the Alarmone (p)ppGpp  

PubMed Central

The outer membrane is the first line of defense for Gram-negative bacteria and serves as a major barrier for antibiotics and other harmful substances. The biosynthesis of lipopolysaccharides (LPS), the essential component of the outer membrane, must be tightly controlled as both too much and too little LPS are toxic. In Escherichia coli, the cellular level of the key enzyme LpxC, which catalyzes the first committed step in LPS biosynthesis, is adjusted by proteolysis carried out by the essential and membrane-bound protease FtsH. Here, we demonstrate that LpxC is degraded in a growth rate-dependent manner with half-lives between 4 min and >2 h. According to the cellular demand for LPS biosynthesis, LpxC is degraded during slow growth but stabilized when cells grow rapidly. Disturbing the balance between LPS and phospholipid biosynthesis in favor of phospholipid production in an E. coli strain encoding a hyperactive FabZ protein abolishes growth rate dependency of LpxC proteolysis. Lack of the alternative sigma factor RpoS or inorganic polyphosphates, which are known to mediate growth rate-dependent gene regulation in E. coli, did not affect proteolysis of LpxC. In contrast, absence of RelA and SpoT, which synthesize the alarmone (p)ppGpp, deregulated LpxC degradation resulting in rapid proteolysis in fast-growing cells and stabilization during slow growth. Our data provide new insights into the essential control of LPS biosynthesis in E. coli. PMID:23417489

Schäkermann, Michael; Langklotz, Sina

2013-01-01

59

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. PMID:1657786

Mayer, A M; Spitzer, J A

1991-01-01

60

Neural Substrate of Cold-Seeking Behavior in Endotoxin Shock  

PubMed Central

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

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

2006-01-01

61

Neural substrate of cold-seeking behavior in endotoxin shock.  

PubMed

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

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

2006-01-01

62

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

2004-01-01

63

Effect of an irradiated Escherichia coli endotoxin reparation on the sensitivity to a lymphotropic cytostatic agent in germfree and conventional mice.  

PubMed

A 18 mg/kg dose of dianhydrodulcitol, a lymphotropic cytostatic agent produced the same death rate among germfree as a 12 mg/kg dose did in conventional mice. Pretreatment with the same dose of an irradiated immunomodulatory endotoxin preparation had increased the sensitivity to these dianhydrodulcitol doses in the same degree in germfree as in conventional mice. A study of the lymphoid organs and the intestinal wall indicate that both in germfree and conventional mice the dianhydrodulcitol sensitivity increasing effect of the endotoxin preparation was due to its stimulation of the lymphoid system. The higher resistance of germfree mice to dianhydrodulcitol is ascribed to their lack of a normal intestinal flora. PMID:6372357

Anderlik, P; Szeri, I; Bános, Z; Wessely, M; Bertók, L; Radnai, B

1983-01-01

64

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

PubMed Central

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

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

2013-01-01

65

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

PubMed

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

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

2015-03-01

66

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

PubMed Central

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 ?-d-GlcpN4P-(1?6)-?-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-MSn 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 ?-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

2010-01-01

67

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

Microsoft Academic Search

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

GUI-HANG ZHANG; DAVID M. MANN; CHAO-MING TSAI

1999-01-01

68

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

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

69

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 PMID:7635960

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

1995-01-01

70

Chronic systemic endotoxin exposure: an animal model in experimental hepatic encephalopathy.  

PubMed

Plasma levels of gut-derived endotoxins (lipopolysaccharides, LPS) are often elevated in cirrhotics and are thought to contribute to hepatic encephalopathy. Circulating LPS activates macrophages to produce tumor necrosis factor alpha (TNF-alpha) and other potentially cytotoxic proinflammatory mediators. A pathogenic role for endotoxins is supported by studies showing that treatment with Lacto-bacillusor antibiotics, both of which reduce LPS-producing intestinal Gram-negative bacteria, alleviates experimental liver damage. To mimic the "leaky gut" syndrome with endotoxin translocation into the circulation in cirrhotics, a new animal model was developed. Rats were chronically exposed to ethanol and for the four last weeks also infused with endotoxin into the jugular vein from subcutaneously implanted osmotic minipumps. Animals receiving endotoxin had elevated hepatic expression of both pro- and anti-inflammatory cytokines, but compared to ethanol treatment alone hepatic steatosis and inflammatory changes were only marginally increased. This demonstrates marked endotoxin tolerance, probably as a consequence of a counteracting anti-inflammatory cytokine response. The role of gut-derived endotoxin in hepatic encephalopathy has recently received considerable attention. To further delineate the role and actions of endotoxin and its extrahepatic effects, studies applying both acute challenge and chronic infusion seem warranted. The chronic endotoxin model, mimicking the "leaky gut," may best be combined with more robust ways to impair liver function, such as carbon tetrachloride treatment, bile duct ligation, or galactosamine administration. PMID:16382349

Lindros, Kai O; Järveläinen, Harri A

2005-12-01

71

A Cholinergic Agonist Attenuates Endotoxin-Induced Uveitis in Rats  

Microsoft Academic Search

METHODS. Lipopolysaccharide (LPS; endotoxin) and nicotine were injected intraperitoneally. Clinical scores were evaluated by slit lamp. Intracameral protein content and the number of cells were determined. Immunohistochemical reactivity of 7 nicotine acetylcholine receptor (7nAChR) was examined in the iris and ciliary body (ICB). mRNA and protein levels of cytokines and chemokines were measured by real-time PCR and enzyme-linked immunosorbent assay.

Zai-Long Chi; Seiji Hayasaka; Xue-Yun Zhang; Hu-Shan Cui; Yoriko Hayasaka

72

Antiproteases modulate bronchial epithelial cell responses to endotoxin.  

PubMed

Escherichia coli endotoxin (0.1 to 1000 micrograms/ml) stimulated the release of neutrophil chemotactic activity (P < 0.001) and induced bronchial epithelial cell (BEC) cytotoxicity assessed by lactate dehydrogenase release (P < 0.001). Endotoxin (100 micrograms/ml) inhibited BEC accumulation (P < 0.001). In the present study, we investigated the role of proteolytic activity of BECs per se in response to endotoxin. Several structurally and functionally different antiproteases, alpha 1 protease inhibitor, soybean trypsin inhibitor, two chloromethyl ketone derivatives (N-tosyl-L-lysine chloromethyl ketone and methoxysuccinyl-Ala-Ala-Pro-Val chloromethyl ketone), and L-658,758, a neutrophil elastase inhibitor, attenuated the release of neutrophil chemotactic activity and lactate dehydrogenase (P < 0.01). alpha 1-Protease inhibitor and N-tosyl-L-lysine chloromethyl ketone attenuated the inhibition of BEC accumulation by endotoxin (P < 0.001). The proteolytic enzyme activity measured by synthetic substrates revealed that endotoxin significantly augmented the serine proteolytic activity in the cell layers. Culture supernatant fluids and cell lysates of BECs in the presence of endotoxin solubilized 14C-labeled casein. These data suggest that responses of BECs to endotoxin may involve activation of cellular proteolytic activity. PMID:7747815

Koyama, S; Rennard, S I; Claassen, L; Robbins, R A

1995-05-01

73

Kinetics of Hydrothermal Inactivation of Endotoxins ?  

PubMed Central

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

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

2011-01-01

74

Fourier transform infrared spectroscopy characterization of the lamellar and nonlamellar structures of free lipid A and Re lipopolysaccharides from Salmonella minnesota and Escherichia coli.  

PubMed Central

The structural polymorphism of free lipid A and deep rough mutant lipopolysaccharide (LPS Re) from Salmonella minnesota strain R595 and Escherichia coli strain F515 was characterized by Fourier transform infrared (IR) spectroscopy. For this, the beta <--> alpha phase states and the three-dimensional supramolecular structures, the latter deduced from small-angle synchrotron radiation x-ray diffraction, were investigated at different water contents, Mg2+ concentrations, and temperatures. The analysis of the IR data for vibrations originating from the hydrophobic moiety shows that the beta <--> alpha acyl chain melting is strongly expressed only for the stretching and scissoring modes of the methylene groups. Vibrational groups originating from the interface region sense the acyl chain melting well (ester carbonyl bands) or only weakly (amide bands), and those resulting from the pure polar moiety not at all. From the x-ray data, the existence of lamellar (L), different cubic, and, for lipid A and LPS R595, also inverted hexagonal (HII) structures could be proven in the temperature range 20-80 degrees C with cubic <--> cubic and cubic <--> HII transitions for the Mg(2+)-free and L <--> HII transitions for the Mg(2+)-containing samples. These structural transitions can be characterized most readily by specific changes of the vibrational bands resulting from the interface region: the ester carbonyl and the amide bands. The magnitude of the changes corresponds to that of the structural rearrangement, i.e., is highest for the L <--> HII, lower for the cubic <--> HII, and lowest for the cubic <--> cubic transitions. The structural transitions are only marginally expressed for vibrational bands of the hydrophobic moiety. Similarly, the band contours of vibrations from the hydrophilic region are no indicators of the structural reorientations except for the carboxylate bands of LPS Re. Particularly the stretching vibrations of the phosphate groups are nearly completely invariant; the absolute values of their half bandwidths, however, differ significantly for lipid A and LPS Re, which seems to be of biological relevance. The ability of IR spectroscopy to detect supramolecular changes also beyond the measurability by x-ray diffraction, i.e., at water contents > 95 to 99.5%, is demonstrated. PMID:8494979

Brandenburg, K

1993-01-01

75

Cynandione A attenuates lipopolysaccharide-induced production of inflammatory mediators via MAPK inhibition and NF-?B inactivation in RAW264.7 macrophages and protects mice against endotoxin shock.  

PubMed

Cynanchum wilfordii has been traditionally used in eastern Asia for the treatment of various diseases such as gastrointestinal diseases and arteriosclerosis. Cynandione A (CA), an acetophenone, is one of major constituents from roots of C. wilfordii. In the present study, the anti-inflammatory activities of CA were investigated in lipopolysaccharide (LPS)-treated RAW264.7 macrophages and LPS-administered C57BL/6?N mice. CA significantly decreased LPS-induced production of nitric oxide and prostaglandin E2 in a dose-dependent manner, while CA up to 200??M did not exhibit cytotoxic activity. Our data also showed that CA significantly attenuated expression of iNOS and COX-2 in LPS-stimulated macrophages. CA inhibited phosphorylation of I?B-? and MAP kinases such as ERK and p38. Furthermore, we demonstrated that CA inhibited translocation of NF-?B to the nucleus, transcription of the NF-?B minimal promoter and NF-?B DNA binding activity. Administration of CA significantly decreased the plasma levels of pro-inflammatory cytokines such as TNF-?, IL-6, and IL-1? in LPS-injected mice and improved survival of septic mice with lethal endotoxemia. These results demonstrate that CA has effective inhibitory effects on production of inflammatory mediators via suppressing activation of NF-?B and MAPK signaling pathways, suggesting that CA may be used as a potential anti-inflammatory agent for the prevention and treatment of inflammatory diseases. PMID:25361770

Kim, Sung Hwan; Lee, Tae Hoon; Lee, Sang Min; Park, Ji Hae; Park, Keun Hyung; Jung, Mira; Jung, Hana; Mohamed, Mohamed Antar Aziz; Baek, Nam-In; Chung, In Sik; Kim, Jiyoung

2014-10-30

76

Anti-endotoxin therapy in primate bacteremia with HA-1A and BPI.  

PubMed Central

OBJECTIVE: The in vivo neutralizing activities of an anti-lipopolysaccharide (LPS) antibody HA-1A (Centoxin [Centocor, Malvern, PA]), a human immunoglobulin M monoclonal antibody, and of bactericidal/permeability-increasing protein (BPI), an endogenously produced human LPS-neutralizing protein, were studied in a primate model of lethal Escherichia coli bacteremia. SUMMARY BACKGROUND DATA: HA-1A has been used with variable success against LPS activity in some animal models and in a recently reported clinical trial. However, no data assessing the efficacy of this agent in subhuman primates is available. Bactericidal/permeability-increasing protein is a product of polymorphomononuclear cells (PMNs) that is stored in azurophilic granules and exhibits LPS-neutralizing activity in vitro and in some in vivo models. METHODS: Immediately after E. coli infusion and in a blinded fashion, three baboons were treated with BPI (5 mg/kg bolus infusion and 95 micrograms/kg/min infusion over 4 hr). Three animals received 3 mg/kg BW of HA-1A, whereas another three baboons received a placebo treatment. RESULTS: The BPI-treated animals demonstrated significantly (p < 0.03) lower circulating LPS-limulus amoebocyte lysate (LAL) activity compared with the control animals, but this reduction in LPS-LAL activity was not associated with improved survival. HA-1A treatment did not reduce LPS-LAL activity. However, both BPI and HA-1A treatment did attenuate the pro-inflammatory cytokine response. CONCLUSION: The current data suggests that incomplete neutralization of endotoxin activity does not alter mortality from severe bacteremia. Given the diversity of mediator production under such circumstances, a strategy of combination therapy in the form of anti-lipopolysaccharide and anticytokine treatment may be necessary to achieve optimal survival. PMID:8024362

Rogy, M A; Moldawer, L L; Oldenburg, H S; Thompson, W A; Montegut, W J; Stackpole, S A; Kumar, A; Palladino, M A; Marra, M N; Lowry, S F

1994-01-01

77

Efficacy of the combination of tachyplesin III and clarithromycin in rat models of Escherichia coli sepsis.  

PubMed

We investigated the efficacy of tachyplesin III and clarithromycin in two experimental rat models of severe gram-negative bacterial infections. Adult male Wistar rats were given either (i) an intraperitoneal injection of 1 mg/kg Escherichia coli 0111:B4 lipopolysaccharide or (ii) 2 x 10(10) CFU of E. coli ATCC 25922. For each model, the animals received isotonic sodium chloride solution, 1 mg/kg tachyplesin III, 50 mg/kg clarithromycin, or 1 mg/kg tachyplesin III combined with 50 mg/kg clarithromycin intraperitoneally. Lethality, bacterial growth in the blood and peritoneum, and the concentrations of endotoxin and tumor necrosis factor alpha (TNF-alpha) in plasma were evaluated. All the compounds reduced the lethality of the infections compared to that for the controls. Tachyplesin III exerted a strong antimicrobial activity and achieved a significant reduction of endotoxin and TNF-alpha concentrations in plasma compared to those of the control and clarithromycin-treated groups. Clarithromycin exhibited no antimicrobial activity but had a good impact on endotoxin and TNF-alpha plasma concentrations. A combination of tachyplesin III and clarithromycin resulted in significant reductions in bacterial counts and proved to be the most-effective treatment in reducing all variables measured. PMID:18779356

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

2008-12-01

78

Endotoxin-like properties of the peptidoglycan.  

PubMed

Peptidoglycan is responsible for the endotoxin-like properties of the streptococcus cell wall. The pyrogenic response of rabbit to group A streptococcus peptidoglycan prepared by hot formamide or TCA is dose-dependent and is increased if the material is ultrasonically solubilized. The pyrogenicity can be eliminated by the antiserum to the peptidoglycan or by the degradation of the material by lysozyme. Peptidoglycans prepared from cell walls of group B and L streptococci, Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus pneumoniae produce fever effects comparable to the response after group A streptococcus peptidoglycan. Spirillum serpens and Escherichia coli contain in addition to endotoxin the peptidoglycan which is also pyrogenic. Repeated injections of bacterial peptidoglycan to rabbit result in tolerance to the fever effect. Cross-tolerance was recorded only exceptionally. Rabbits tolerant to endotoxin respond with a lower fever to S. aureus and group A streptococcus peptidoglycans. Intravenous administration of peptidoglycan to rabbit causes extensive alterations in the heart characterized by various stages of the degenerative and necrotic process. Local Shwartzman reaction can be elicited in rabbit by peptidoglycan used either as a preparative or as a provocative dose in combination with endotoxin, or it can be used for both doses. The results obtained with peptidoglycans prepared from various bacteria are fully comparable. Non-specific resistance of mice to infection induced by streptococcus cell walls was found to be dependent on the peptidoglycan activity; cell wall proteins and polysaccharide are inactive. These properties of peptidoglycan resemble those known from endotoxin studies. The data presented suggest the role of peptidoglycan in pathological reactions resulting from host-parasite interaction. PMID:126556

Rotta, J

1975-07-01

79

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

Microsoft Academic Search

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

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

1994-01-01

80

Role of Oxygen Radicals in Tissue Factor Induction by Endotoxin in Blood Monocytes  

Microsoft Academic Search

In response to bacterial endotoxin (lipopolysaccharide, LPS) monocytes synthesize and express on their surface tissue factor (TF) which triggers the blood coagulation cascade. Since LPS stimulates active oxygen species production by these cells, we investigated the roles of superoxide anion and nitric oxide in the induction of TF in human blood monocytes. Scavengers of reactive oxygen intermediates such as N-acetyl

Benoît Polack; Gilles Pernod; Claire Barro; Jacques Doussičre

1997-01-01

81

The Immunomodulatory Effect of Sevoflurane in Endotoxin-Injured Alveolar Epithelial Cells  

Microsoft Academic Search

BACKGROUND: Endotoxin-induced lung injury is a useful experimental system for the characterization of immunopathologic mechanisms in acute lung injury. Although alveolar epithelial cells (AEC) are directly exposed to volatile anesthetics, there is limited information about the effect of anesthetics on these cells. In this study we investigated the effect of pretreatment with the inhaled anesthetic sevoflurane on lipopolysaccharide (LPS)-injured AEC.

Dominik Suter; Donat R. Spahn; Stephan Blumenthal; Livia Reyes; Christa Booy; Beatrice Beck-Schimmer

2007-01-01

82

Intrapulmonary lipopolysaccharide exposure upregulates cytokine expression in the neonatal brainstem  

PubMed Central

Perinatal inflammation and neonatal sepsis trigger lung and brain injury. We hypothesized that endotoxin exposure in the immature lung upregulates proinflammatory cytokine expression in the brainstem and impairs respiratory control. Lipopolysaccharide (LPS) or saline was administered intratracheally to vagal intact or denervated rat pups. LPS increased brainstem IL-1? and vagotomy blunted this response. There was an attenuated ventilatory response to hypoxia and increased brainstem IL-1? expression after LPS. Conclusion Intratracheal endotoxin exposure in rat pups is associated with upregulation of IL-1? in the brainstem that is vagally mediated and associated with an impaired hypoxic ventilatory response. PMID:22176020

Balan, Kannan V; Kc, Prabha; Mayer, Catherine A; Wilson, Christopher G; Belkadi, Abdelmadjid; Martin, Richard J

2014-01-01

83

Endotoxin and Cancer  

PubMed Central

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

Lundin, Jessica I.; Checkoway, Harvey

2009-01-01

84

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

PubMed

The toxic effects of endotoxin-free human recombinant tumor necrosis factor (rH-TNF), shown to contain less than 50 pg endotoxin/mg rH-TNF, were investigated and compared with those of rH-TNF and endotoxin coadministered at 4-400 ng endotoxin/mg rH-TNF in female Sprague-Dawley rats. The mean lethal dose of 5.9 mg/kg rH-TNF found for the endotoxin-free rH-TNF was far higher than that attributed to rH-TNF by other investigators. Coadministration with endotoxin derived from E. Coli. Salmonella abortus equi, or Serratia marcescens reduced the apparent mean lethal dose of rH-TNF in correspondence to the endotoxin concentration, with a value of 0.7 mg/kg rH-TNF observed at 1600 ng, 757 ng, and 5260 ng endotoxin/mg rH-TNF, respectively. Coadministration also resulted in more severe histopathologic and physicochemical effects than rH-TNF alone. Histopathologic abnormalities observed only in coadministration included interlobular edema and hemorrhage of the pancreas and, most remarkably, splenomegaly, which was not observed with rH-TNF alone even at lethal doses. The results indicate that particular care in determining endotoxin contamination is essential in any consideration of TNF toxicity. PMID:2522355

Ozaki, Y; Oyama, T; Kume, S

1989-01-01

85

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

PubMed Central

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 3H-labeled endotoxin from the membrane was performed, resulting in the removal of endotoxin associated with the membrane by alcoholic alkali at 78% efficiency. Images PMID:3518630

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

1986-01-01

86

Response of Saccharomyces cerevisiae to the Stimulation of Lipopolysaccharide  

PubMed Central

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

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

2014-01-01

87

On the Essentiality of Lipopolysaccharide to Gram-Negative Bacteria  

PubMed Central

Lipopolysaccharide is a highly acylated saccharolipid located on the outer leaflet of the outer membrane of Gram-negative bacteria. Lipopolysaccharide is critical to maintaining the barrier function preventing the passive diffusion of hydrophobic solutes such as antibiotics and detergents into the cell. Lipopolysaccharide has been considered an essential component for outer membrane biogenesis and cell viability based on pioneering studies in the model Gram-negative organisms Escherichia coli and Salmonella. With the isolation of lipopolysaccharide-null mutants in Neisseria meningitides, Moraxella catarrhalis, and most recently in Acinetobacter baumannii, it has become increasingly apparent that lipopolysaccharide is not an essential outer membrane building block in all organisms. We suggest the accumulation of toxic intermediates, misassembly of essential outer membrane porins, and outer membrane stress response pathways that are activated by mislocalized lipopolysaccharide may collectively contribute to the observed strain-dependent essentiality of lipopolysaccharide. PMID:24148302

Zhang, Ge; Meredith, Timothy C.; Kahne, Daniel

2013-01-01

88

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

PubMed

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

Duquenne, Philippe; Marchand, Genevičve; Duchaine, Caroline

2013-03-01

89

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

PubMed Central

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

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

2014-01-01

90

Endotoxin structures in the psychrophiles Psychromonas marina and Psychrobacter cryohalolentis contain distinctive acyl features.  

PubMed

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

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

2014-07-01

91

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

PubMed Central

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

Schmied, Julie; Rupa, Prithy; Garvie, Sarah

2012-01-01

92

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

Microsoft Academic Search

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

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

2004-01-01

93

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

PubMed

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

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

2014-01-01

94

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

PubMed Central

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

2014-01-01

95

Growing tumors induce hypersensitivity to endotoxin and tumor necrosis factor.  

PubMed Central

Lewis lung carcinoma and EMT6 sarcoma growing as solid tumors in mice caused a gradual increase in the susceptibility of the animals to lethal toxicity of endotoxins (lipopolysaccharides [LPS]). By day 15 following inoculation of the tumors, the 50% lethal dose of LPS, which in normal mice was approximately 400 micrograms, decreased to 2 micrograms for the sarcoma-bearing mice and 0.1 microgram for the carcinoma-bearing mice. This sensitization to endotoxin was paralleled by a high sensitization to tumor necrosis factor (TNF). Human recombinant TNF given to normal mice was lethal at about 500 micrograms. It was lethal for 50% of the animals bearing EMT6 or Lewis lung carcinoma tumors in amounts of 4 and 0.01 micrograms, respectively, on day 15 following tumor inoculation. The sensitization of tumor-bearing animals to LPS and TNF was paralleled by marked granulocytosis. PMID:3623699

Bartholeyns, J; Freudenberg, M; Galanos, C

1987-01-01

96

Renal perfusion and metabolism in experimental endotoxin shock.  

PubMed

Central and renal hemodynamics, renal oxygenation, renal uptake of glucose, lactate, fats, renal carnitine metabolism, arterial atrial natriuretic factor (ANF) and catecholamine release were studied in sixteen adult beagle dogs during pentobarbital anesthesia. Renal cortical oxygen tension was recorded by means of a Silastic tonometer. Twelve animals underwent acute circulatory shock induced by intravenous Escherichia coli endotoxin 0.5 mg/kg. Four control dogs received normal saline. The endotoxin infusion resulted in decreased cardiac function, renal blood flow and renal cortical PO2. The renal venous PO2 increased during the experiment. Arterial and renal venous glucose concentrations increased transiently during endotoxemia. Circulating lactate concentrations increased significantly whereas the arteriovenous lactate difference remained almost unchanged. Renal uptake of lactate and glucose were not influenced during the moderate renal hypoperfusion caused by endotoxin. Arterial free fatty acid (FFA) concentrations increased significantly 2 hours after onset of the endotoxin infusion whereas renal venous FFA levels remained rather stationary. The renal uptake of FFA increased with increasing arterial FFA concentrations. Circulating free carnitine concentrations increased significantly in endotoxin shock. Blood acyl-carnitine concentrations remained essentially unchanged. Carnitine concentrations declined significantly in endotoxic renal tissue. The arterial concentrations of ANF, epinephrine, norepinephrine and the norepinephrine metabolite 3,4-dihydroxyphenylglycol (DHPG) increased in plasma during early endotoxemia. The levels of these hormones remained very low and constant in the controls. To summarize, endotoxin injection resulted in impaired renal perfusion and oxygenation, increased uptake of free fatty acids and unchanged uptake of glucose, lactate, glycerol and triglycerides. Decreased renal carnitine concentrations were observed. Arterial plasma concentrations of ANF and catecholamines increased in endotoxin shock. PMID:1828126

Gullichsen, E

1991-01-01

97

Maternal supplementation with fishmeal protects against late gestation endotoxin-induced fetal programming of the ovine hypothalamic-pituitary-adrenal axis.  

PubMed

Adverse uterine environments caused by maternal stress (such as bacterial endotoxin) can alter programming of the fetal hypothalamic-pituitary-adrenal axis (HPAA) rendering offspring susceptible to various adulthood diseases. Thus, protection against this type of stress may be critical for ensuring offspring health. The present study was designed to determine if maternal supplementation with omega-3 polyunsaturated fatty acids (n-3 PUFAs) during pregnancy helps to protect against stress-induced fetal programming. Briefly, 53 ewes were fed a diet supplemented with fishmeal (FM) or soybean meal (SM) from day 100 of gestation (gd100) through lactation. On gd135, half the ewes from each dietary group were challenged with either 1.2 ?g/kg Escherichia coli lipopolysaccharide (LPS) endotoxin, or saline as the control. The offspring's cortisol response to weaning stress was assessed 50 days postpartum by measuring serum cortisol concentrations 0, 6 and 24 h post weaning. Twenty-four hours post-weaning, lambs were subjected to an adrenocorticotropic hormone (ACTH) challenge (0.5 ?g/kg) and serum cortisol concentrations were measured 0, 0.25, 0.5, 1 and 2 h post injection. At 5.5 months of age, offspring were also challenged with 400 ng/kg of LPS, and serum cortisol concentrations were measured 0, 2, 4 and 6 h post challenge. Interestingly, female offspring born to FM+LPS mothers had a greater cortisol response to weaning and endotoxin challenge compared with the other treatments, while female offspring born to SM+LPS mothers had a faster cortisol response to the ACTH stressor. Additionally, males born to FM+LPS mothers had a greater cortisol response to the ACTH challenge than the other treatments. Overall, FM supplementation during gestation combined with LPS challenge alters HPAA responsiveness of the offspring into adulthood. PMID:24901660

Fisher, R E; Or'Rashid, M; Quinton, M; AlZahal, O; Boermans, H J; McBride, B W; Karrow, N A

2014-06-01

98

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

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

99

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

100

Effects of organic chemicals derived from ambient particulate matter on lung inflammation related to lipopolysaccharide  

Microsoft Academic Search

The effects of components of ambient particulate matter (PM) on individuals with predisposing respiratory disorders are not well defined. We have previously demonstrated that airway exposure to diesel exhaust particles (DEP) or organic chemicals (OC) extracted from DEP (DEP–OC) enhances lung inflammation related to bacterial endotoxin (lipopolysaccharide, LPS). The present study aimed to examine the effects of airway exposure to

Ken-ichiro Inoue; Hirohisa Takano; Rie Yanagisawa; Seishiro Hirano; Takahiro Kobayashi; Takamichi Ichinose; Toshikazu Yoshikawa

2006-01-01

101

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

2011-05-01

102

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

PubMed

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

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

2015-01-01

103

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

PubMed

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

2013-07-01

104

Chlamydial hemagglutinin identified as lipopolysaccharide.  

PubMed

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

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

1987-08-01

105

Oxidative degradation of endotoxin by advanced oxidation process (O3/H2O2 & UV/H2O2).  

PubMed

The presence of endotoxin in water environments may pose a serious public health hazard. We investigated the effectiveness of advanced oxidative processes (AOP: O3/H2O2 and UV/H2O2) in the oxidative degradation of endotoxin. In addition, we measured the release of endotoxin from Escherichia coli following typical disinfection methods, such as chlorine, ozone alone and UV, and compared it with the use of AOPs. Finally, we tested the AOP-treated samples in their ability to induce tumor necrosis factor alpha (TNF-?) in mouse peritoneal macrophages. The production of hydroxyl radical in AOPs showed superior ability to degrade endotoxin in buffered solution, as well as water samples from Korean water treatment facilities, with the ozone/H2O2 being more efficient compared to UV/H2O2. In addition, the AOPs proved effective not only in eliminating E. coli in the samples, but also in endotoxin degradation, while the standard disinfection methods lead to the release of endotoxin following the bacteria destruction. Furthermore, in the experiments with macrophages, the AOPs-deactivated endotoxin lead to the smallest induction of TNF-?, which shows the loss of inflammation activity, compared to ozone treatment alone. In conclusion, these results suggest that AOPs offer an effective and mild method for endotoxin degradation in the water systems. PMID:25038578

Oh, Byung-Taek; Seo, Young-Suk; Sudhakar, Dega; Choe, Ji-Hyun; Lee, Sang-Myeong; Park, Youn-Jong; Cho, Min

2014-08-30

106

Interleukin1 a, Interleukin1\\/?, and Tumor Necrosis Factor Gene Expression in Endotoxin-Induced Uveitis  

Microsoft Academic Search

Purpose. To localize and determine the levels of interleukin-1 a (IL-la), interleukin-1\\/3 (IL-lj8), and tumor necrosis factor (TNF) gene expression in the process of endotoxin-induced uveitis (EIU) in rats. Method. EIU was induced by lipopolysaccharide (LPS) injection in male Lewis rats weighing 150 to 200 g. The levels of IL-la, IL-1\\/3, and TNF gene expression in the iris-ciliary body (ICB)

Munenori Yoshida; Nagahisa Yoshimura; Masanori Hangai; Hidenobu Tanihara; Yoshihito Honda

1994-01-01

107

Endotoxin-induced protein phosphorylation in macrophages is modulated by tumor cells  

Microsoft Academic Search

Tumor cells are known to modulate the antitumor functions of endotoxin or cytokine-stimulated macrophages, however, their mechanism of action is not known. We have recently shown that Daltonsfn2fn2DL, Daltons lymphoma; DLL, DL cell lysate; LPS, lipopolysaccharide; PKC, protein kinase C; PTK, protein tyrosine kinase; PEC, peritoneal exudate cells; PBS, phosphate buffer saline; NO, nitric oxide; IL, interleukin; TNF, tumor necrosis

Ashok Kumar; Sukh Mahendra Singh; Ajit Sodhi

1998-01-01

108

In Vivo Quantification of Leukocyte Behavior in the Retina During Endotoxin-Induced Uveitis  

Microsoft Academic Search

Purpose. The interaction between leukocytes and vascular endothelial cells plays an important role in various inflammatory disorders. This study evaluated leukocyte behavior in the retina during endotoxin-induced uveitis (EIU) in vivo. Methods. EIU was induced in female Lewis rats by footpad injection of lipopolysaccharide (LPS). The time-course changes of retinal leukocyte behavior were followed at 1.5, 3, 4.5, 6, 12,

Kazuaki Miyamoto; Yuichiro Ogura; Muneo Hamad; Hirokazu Nishiwaki; Naoko Hiroshiba; Yoshihito Honda

109

In silico designed nanoMIP based optical sensor for endotoxins monitoring.  

PubMed

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

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

2015-05-15

110

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

SciTech Connect

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

Mundie, T.G.

1993-06-02

111

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

PubMed Central

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

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

2013-01-01

112

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

PubMed Central

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

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

1980-01-01

113

Influence of the apical enlargement size on the endotoxin level reduction of dental root canals  

PubMed Central

Gram-negative bacteria play an essential role in endodontic infections because they have virulence factors such as endotoxin. Due to its potential cytotoxic activity, special attention has been given to the removal/neutralization of this endotoxin in the root canal system. Objective The aim of this study was to evaluate the influence of the apical enlargement size (AES) by using rotary instruments on the endotoxin level reduction of dental root canals. Material and Methods Forty root canals of the mandibular premolar teeth were used. Escherichia coli endotoxin (055: B55) was inoculated into thirty root canals. Ten teeth served as the negative control group. After the incubation period, the first endotoxin samples were collected from the root canals with a sterile/apyrogenic paper point for the analysis of the endotoxin units (EU/mL) present before instrumentation (S1). Specimen instrumentation was performed with the Mtwo® rotary system in the sequence 10/.04, 15/.05, 20/.06, 25/.06, 30/.05, 35/.04 and 40/.04. To monitor the effectiveness of increasing apical enlargement on endotoxin removal, the second endotoxin samples were collected from all the root canals after instrumentation with the following instruments: #25/.06- (S2); #30/.05- (S3); # 35/.04- (S4); and #40/.04- (S5). Limulus amebocyte lysate (LAL) was used to quantify the levels of endotoxin. The results were statistically compared by using repeated measures of ANOVA with post hoc Tukey testing. Results Increasing levels of endotoxin removal was achieved by large sized apical enlargement: S2 (AES #25/.06)- 89.2%, S3 (AES #30/.05)- 95.9%, S4 (AES #35/.04)- 97.8% and S5 (AES #40/.04)- 98.2%. Substantial reduction of endotoxin content was obtained in S4 and S5 compared to S2 (p<0.05), however, the root canal preparation was not able to eliminate the endotoxin. Conclusions Under the conditions of this study, it was concluded that the reduction of endotoxin levels of the dental root canals could be predicted by increasing the apical enlargement size. PMID:23329249

MARINHO, Ariane Cassia Salustiano; MARTINHO, Frederico Canato; ZAIA, Alexandre Augusto; FERRAZ, Caio Cezar Randi; GOMES, Brenda Paula Figueiredo de Almeida

2012-01-01

114

Late effects of endotoxin on the accumulation and function of monocytes in rabbit lungs.  

PubMed

Recent studies from our laboratory show that the lung contains a marginated pool of monocytes. The present study was designed to investigate monocyte accumulation in this pool 4 to 28 h after a single dose of endotoxin when the endotoxin had disappeared from the circulation. This was accomplished by administering a single intravenous dose of endotoxin (Escherichia coli, 50 micrograms/rabbit) to unanesthetized animals (n = 6) and saline to controls (n = 5) at time 0. Four hours after this dose of endotoxin, 111In-monocytes (93.5% pure) isolated from donors were injected intravenously, and, at 27 h, the rabbits were anesthetized and colloidal carbon (CC, 1 ml/kg body weight) was injected intraarterially to provide a phagocytic stimulus. The animals were sacrificed at 28 h, and the lungs were fixed in situ with glutaraldehyde. The data show that lungs from the endotoxin-treated rabbits contained 4.8 times more 111In-monocytes than controls, that 92% of these radiolabeled monocytes were in the alveolar capillaries, and that 72% of these labeled cells had phagocytosed CC. The histologic studies of unlabeled cells confirmed that this endotoxin treatment caused a 3-5-fold increase in unlabeled mononuclear cells and neutrophils (PMN) in the microvasculature and that many of the unlabeled monocytes in the endotoxin-treated group had also phagocytosed colloidal carbon. The behavior of the donor monocytes injected after the endotoxin had time to disappear from the circulation suggests that they accumulate in the lung in response to the indirect effects of endotoxin on endothelial cells. PMID:1626802

Ohgami, M; Doerschuk, C M; Gie, R P; English, D; Hogg, J C

1992-07-01

115

Lack of Endotoxin-lnduced Hyporesponsiveness to U46619 in Isolated Neonatal Porcine Pulmonary but Not Mesenteric Arteries  

Microsoft Academic Search

The effects of endotoxin from Escherichia coli on the vasoconstrictor responses to noradrenaline (10 nM–100 ?M) and the thromboxane A2 analog U46619 (100 pM–1 ?M) were evaluated on isolated pulmonary and mesenteric arteries from neonatal piglets. Incubation for 20 h with endotoxin (1 ?g ml–1) induced a decrease in the contractile responses to noradrenaline in both arteries (p < 0.05)

Francisco Pérez-Vizcaíno; Eduardo Villamor; Buensuceso Fernandez del Pozo; Manuel Moro; Juan Tamargo

1996-01-01

116

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

PubMed Central

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

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

2014-01-01

117

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...

118

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. PMID:23133491

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

2012-01-01

119

Predictors of airborne endotoxin in the home.  

PubMed Central

We identified home characteristics associated with the level of airborne endotoxin in 111 Boston-area homes enrolled in a cohort study of home exposures and childhood asthma, and we developed a predictive model to estimate airborne endotoxin. We measured endotoxin in family-room air and in dust from the baby's bed, family room, bedroom, and kitchen floor. Level of airborne endotoxin was weakly correlated (r < 0.3) with level of endotoxin in each of the four types of dust samples and was significantly correlated with endotoxin in family-room dust (p < 0.05). Endotoxin in family-room dust accounted for < 6% of the variability of airborne endotoxin. In a multivariate model, certain home characteristics were positively (p < 0.05) associated with airborne endotoxin. These included current presence of dog (difference in level, dog vs. no dog = 72%, partial R(2 )= 12.8%), past presence of dog (partial R(2) = 5.5%), and endotoxin level in family-room dust (partial R(2) = 5.3%). Use of a dehumidifier (partial R(2) = 6.4%) was negatively associated (p = 0.02; difference = -31%) with airborne endotoxin. Other home characteristics were identified as important determinants of increased airborne endotoxin in this model, but individual coefficients were not statistically significant (alpha = 0.05): total amount of fine dust collected in the home (partial R(2 )= 3.8%), concrete floor in family room (3.7%), water damage (3.6%), and use of cool-mist humidifier in past year (2.7%). This multivariate model explained 42% of the variability of airborne endotoxin levels, a substantial improvement over that with dust endotoxin alone. Airborne endotoxin in Boston-area homes appears to be determined by the presence of dogs, moisture sources, and increased amounts of settled dust. PMID:11564624

Park, J H; Spiegelman, D L; Gold, D R; Burge, H A; Milton, D K

2001-01-01

120

Effects of inhibitors of the activity of cyclo-oxygenase-2 on the hypotension and multiple organ dysfunction caused by endotoxin: A comparison with dexamethasone  

PubMed Central

Endotoxaemia is associated with the expression of the inducible isoform of cyclo-oxygenase, cyclo-oxygenase-2 (COX-2), and an overproduction of arachidonic acid (AA) metabolites. The role of the AA metabolites generated by COX-2 in the circulatory failure and multiple organ dysfunction caused by endotoxin is unclear. Dexamethasone prevents the expression of COX-2 and exerts beneficial effects in animal models of shock.Here we compare the effects of two inhibitors of COX-2 activity, namely NS-398 (5?mg?kg?1, i.p., n=7) and SC-58635 (3?mg?kg?1, i.p., n=9) with those of dexamethasone (3?mg?kg?1, i.p., n=9) on the circulatory failure and organ dysfunction caused by lipopolysaccharide (LPS, E. coli, 6?mg?kg?1, i.v., n=11) in the rat.Endotoxaemia for 6?h caused hypotension, acute renal dysfunction, hepatocellular injury, pancreatic injury and an increase in the plasma levels of 6-keto-PGF1? (indicator of the induction of COX-2) and nitrite/nitrate (indicator of the induction of iNOS).Pretreatment of rats with dexamethasone attenuated the hypotension, the renal dysfunction, the hepatocellular and pancreatic injury and the induction of COX-2 and iNOS caused by LPS. In contrast, inhibition of COX-2 activity with SC-58635 or NS-398 neither attenuated the circulatory failure nor the multiple organ failure caused by endotoxin.Thus, the prevention of the circulatory failure and the multiple organ injury/dysfunction caused by dexamethasone in the rat is not due to inhibition of the activity of COX-2. Our results suggest that an enhanced formation of eicosanoids by COX-2 does not contribute to the development of organ injury and/or dysfunction in rats with endotoxaemia. PMID:9647485

Leach, Mary; Hamilton, Lorna C; Olbrich, Antje; Wray, Gillian M; Thiemermann, Christoph

1998-01-01

121

Mononuclear cells in the corneal response to endotoxin  

SciTech Connect

A severe keratitis can be produced after the direct injection of bacterial endotoxin, or lipopolysaccharide (LPS), in rabbits. Corneal inflammation can progress to scarring and vascularization within a 2 to 3 week period. Pretreatment with systemic adrenal corticosteroids (triamcinolone) prevents this response. Limbal cellular and vascular events were studied during the first 20 hr after injection of LPS in treated and nontreated rabbits. Perivascular limbal inflammatory cells were counted and limbal vascular permeability was assessed by extravasation of 131I-albumin and 125I-fibrinogen in the cornea. Corticosteroids decreased but did not prevent the early protein extravasation and profoundly altered the inflammatory cell population around blood vessels at the limbus. Mononuclear cells, particularly mononuclear phagocytes, were sharply reduced. It is proposed that these cell types play an important role in the perpetuation and amplification of the inflammatory response in this reaction.

Howes, E.L.; Cruse, V.K.; Kwok, M.T.

1982-04-01

122

Structural Correlation Between Lipophilicity and Lipopolysaccharide-sequestering activity in Spermine-Sulfonamide Analogs  

PubMed Central

Lipopolysaccharides (LPS), otherwise termed ‘endotoxins’, are outer-membrane constituents of Gram-negative bacteria, and play a key role in the pathogenesis of ‘Septic Shock’, a major cause of mortality in the critically ill patient. We had previously defined the pharmacophore necessary for small molecules to specifically bind and neutralize this complex carbohydrate. A series of aryl and aliphatic spermine-sulfonamide analogs were synthesized and tested in a series of binding and cell-based assays in order to probe the effect of lipophilicity on sequestration ability. A strong correlation was indeed found, supporting the hypothesis that endotoxin-neutralizing ability involves a lipophilic or membrane attachment event. The research discussed herein may be useful for the design of additional carbohydrate recognizing molecules and endotoxin-neutralizing drugs. PMID:17010608

Burns, Mark R.; Jenkins, Scott A.; Vermeulen, Nicolas M.; Balakrishna, Rajalakshmi; Nguyen, Thuan B.; Kimbrell, Matthew R.; David, Sunil A.

2006-01-01

123

The metabolic effects of endotoxin are differentially affected by the pattern of GH administration in the rat  

Microsoft Academic Search

Abstract GH treatment can increase the mortality and morbidity of critically ill patients. The mechanisms,of these harmful effects of GH are unknown but have been, in part, ascribed to interactions between,GH and the immune system. Because GH has pattern-dependent actions we have now compared,the dose-related effects of continuous and intermittent GH treatment given with or without an endotoxin (lipopolysaccharide; LPS)

V Roelfsema; G B Thomas; H Lin; B H Breier; L Maxwell; M H Oliver; E Heineman; R G Clark; P D Gluckman

2001-01-01

124

Regulation of the multidrug resistance protein 2 in the rat liver by lipopolysaccharide and dexamethasone  

Microsoft Academic Search

Background & Aims: Endotoxin lipopolysaccharide (LPS) induces cholestasis and down-regulates the multidrug resistance protein 2 (MRP2). This study intends to characterize the short-term effects of LPS on MRP2. Methods: The effects of LPS and dexamethasone on excretion of bromosulphalein (BSP), MRP2 messenger RNA (mRNA) levels, and subcellular MRP2 localization were studied by means of liver perfusion, Northern blots, and confocal

Ralf Kubitz; Matthias Wettstein; Ulrich Warskulat; Dieter Häussinger

1999-01-01

125

Changes in regional plasma extravasation in rats following endotoxin infusion  

SciTech Connect

Regional differences in plasma extravasation during endotoxin shock in rats and a possible relationship with changes in regional blood flow were studied with radioactive isotopes (/sup 125/I-HSA, 51Cr-labeled red blood cells, microspheres) in anesthetized rats (pentobarbital). Shock was induced by intravenous infusion of endotoxin (Eschericia coli; 10 mg X kg-1) for 60 min (starting at t = 0); at t = 120 min, the experiments were terminated. These rats (n = 8) were compared with time-matched control rats (n = 8). A third group (rats killed 7.5 min after injection of /sup 125/I-HSA, i.e., no extravasation; n = 8) served as baseline. The amount of plasma extravasated in 2 hr of endotoxin shock was significantly increased over control values in skin (by 67%), colon (88%), skeletal muscle (105%), stomach (230%), pancreas (300%), and diaphragm (1300%). Losses of /sup 125/I-HSA into intestinal lumen and peritoneal cavity had also increased over control values by 146 and 380%, respectively. Blood flow was compromised in most organs except heart and diaphragm. Extravasation when normalized for total plasma supply was correlated with total blood supply; the more the blood supply decreased, the higher the normalized extravasation. In the diaphragm, however, blood supply and plasma leakage increased together. Decreased blood supply and plasma extravasation may be related but they could also be simultaneously occurring independent phenomena with a common origin.

van Lambalgen, A.A.; van den Bos, G.C.; Thijs, L.G.

1987-07-01

126

SMAD4 is required for development of maximal endotoxin tolerance  

PubMed Central

Initial exposure of monocytes/macrophages to lipopolysaccharide (LPS) induces hypo-responsiveness to a second challenge with LPS, a phenomenon termed LPS tolerance. Molecular mechanisms responsible for endotoxin tolerance are not well defined. We and others have shown that IRAK-M and SHIP-1 proteins, negative regulators of TLR4 signaling, increase in tolerized cells. TGF?1, an anti-inflammatory cytokine, is up-regulated following LPS stimulation, mediating its effect through SMAD family proteins. Using a monocytic cell line, THP1 we show that LPS activates endogenous SMAD4, inducing its migration into the nucleus and increasing its expression. Secondary challenge with high dose LPS following initial low dose LPS exposure does not increase IRAK-M or SHIP1 protein expression in shSMAD4 THP-1 cells compared with control shLUC THP1 cells. TNF-? concentrations in culture supernatants after second LPS challenge are higher in shSMAD4 THP-1 cells than shLUC THP1 cells, indicating failure to induce maximal tolerance in absence of SMAD4 signaling. Identical results are seen in primary murine macrophages and murine embryonic fibroblasts, demonstrating the biological significance of our findings. TGF-?1 treatment does not increase IRAK-M or SHIP1 protein expression in shSMAD4 THP-1 cells while it does so in shLUC THP1 cells, indicating that TGF-?1 regulates IRAK-M and SHIP1 expression through a SMAD4-dependent pathway. Knockdown of endogenous SHIP1 by shSHIP1 RNA decreases native and inducible IRAK-M protein expression and prevents development of endotoxin tolerance in THP1 cells. We conclude that in THP-1 cells and primary murine cells, SMAD4 signaling is required for maximal induction of endotoxin tolerance via modulation of SHIP1 and IRAK-M. PMID:20404275

Pan, Hongjie; Ding, Enyu; Hu, Mai; Lagoo, Anand S.; Datto, Michael B.; Lagoo-Deenadayalan, Sandhya A

2010-01-01

127

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 PMID:1281827

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

1992-01-01

128

Protection from Oxygen Toxicity with Endotoxin  

PubMed Central

Endotoxin treatment of adult rats before hyperoxic exposure significantly increases their survival rate in >95% O2 (J. Clin. Invest.61: 269, 1978). In this study, we wished to determine: (a) whether endotoxin would protect against O2 toxicity if it were administered after the animals were already in >95% O2 for 12-48 h; and (b) the relationship between the endogenous antioxidant enzymes of the lung and the protective effect of endotoxin treatment. Our results showed that adult rats given a single 500 ?g/kg dose of endotoxin up to 36 h after the onset of O2 exposure had significantly increased survival rates and decreased lung fluid accumulation compared to untreated animals in O2 (P < 0.05). (Survival, 16/49 [untreated rats]; 18/20 [endotoxin at 12 h after the start of O2 exposure]; 25/26 [endotoxin-24 h]; 15/20 [endotoxin-36 h].) Endotoxin-treated animals in O2 showed increases in pulmonary superoxide dismutase, catalase, and glutathione peroxidase activities before the usual time of onset of measurable pulmonary edema in untreated animals in O2. When diethyldithiocarbamate was used to block the superoxide dismutase enzyme rise in the endotoxin-treated rats in O2, the protective action of endotoxin against pulmonary O2 toxicity was nullified. In endotoxin-treated, O2-exposed mice, there were no lung antioxidant enzyme increases, and no protective effect from O2 toxicity was achieved. We conclude that, in the rat, a single dose of endotoxin given even 36 h after the onset of hyperoxic exposure results in marked protection against O2-induced lung damage; and the increased lung antioxidant enzyme activity in the endotoxin-treated rats appears to be an essential component of this protective action. PMID:6245106

Frank, L.; Summerville, J.; Massaro, D.

1980-01-01

129

Network Topologies and Dynamics Leading to Endotoxin Tolerance and Priming in Innate Immune Cells  

PubMed Central

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

2012-01-01

130

Haptoglobin dampens endotoxin-induced inflammatory effects both in vitro and in vivo  

PubMed Central

We report that haptoglobin, an acute-phase protein produced by liver cells in response to interleukin-6 (IL-6), can modulate the inflammatory response induced by endotoxins. We provide evidence that haptoglobin has the ability to selectively antagonize lipopolysaccharide (LPS) effects in vitro by suppressing monocyte production of tumour necrosis factor-?, IL-10 and IL-12, while it fails to inhibit the production of IL-6, IL-8 and IL-1 receptor antagonist. In two animal models of LPS-induced bronchopulmonary hyperreactivity and endotoxic shock, haptoglobin knockout mice were more sensitive to LPS effects compared to their wild-type counterparts. The present data suggest that haptoglobin regulates monocyte activation following LPS stimulation. The increase in haptoglobin levels during an acute-phase reaction may generate a feedback effect which dampens the severity of cytokine release and protects against endotoxin-induced effects. PMID:15667571

Arredouani, Mohamed S; Kasran, Ahmad; Vanoirbeek, Jeroen A; Berger, Frank G; Baumann, Heinz; Ceuppens, Jan L

2005-01-01

131

Fucoidan Extracted from Fucus Evanescens Prevents Endotoxin-Induced Damage in a Mouse Model of Endotoxemia  

PubMed Central

An important problem of treating patients with endotoxemia is to find drugs to reduce the negative effects of endotoxin on the organism. We tested fucoidan (sulfated polysaccharide) from the brown alga Fucus evanescens as a potential drug in a mouse model of endotoxemia inducted by lipopolysaccharide (LPS). The survival time of mice injected with LPS increased under fucoidan treatment compared with the group of mice injected with LPS only. The preventive administration of fucoidan to mice with endotoxemia resulted in inhibition of increased levels of proinflammatory cytokines (TNF? and IL-6), as well as decreasing of the processes of hypercoagulability. The parenteral or per os administration of fucoidan resulted in decreasing the degree of microcirculatory disorders and secondary dystrophic-destructive changes in parenchymal organs of mice with endotoxemia. Taken together, these results demonstrate that fucoidan prevents endotoxin-induced damage in a mouse model of endotoxemia and increases the mice’s resistance to LPS. PMID:24492521

Kuznetsova, Tatyana A.; Besednova, Natalya N.; Somova, Larisa M.; Plekhova, Natalya G.

2014-01-01

132

Fucoidan extracted from Fucus evanescens prevents endotoxin-induced damage in a mouse model of endotoxemia.  

PubMed

An important problem of treating patients with endotoxemia is to find drugs to reduce the negative effects of endotoxin on the organism. We tested fucoidan (sulfated polysaccharide) from the brown alga Fucus evanescens as a potential drug in a mouse model of endotoxemia inducted by lipopolysaccharide (LPS). The survival time of mice injected with LPS increased under fucoidan treatment compared with the group of mice injected with LPS only. The preventive administration of fucoidan to mice with endotoxemia resulted in inhibition of increased levels of proinflammatory cytokines (TNF? and IL-6), as well as decreasing of the processes of hypercoagulability. The parenteral or per os administration of fucoidan resulted in decreasing the degree of microcirculatory disorders and secondary dystrophic-destructive changes in parenchymal organs of mice with endotoxemia. Taken together, these results demonstrate that fucoidan prevents endotoxin-induced damage in a mouse model of endotoxemia and increases the mice's resistance to LPS. PMID:24492521

Kuznetsova, Tatyana A; Besednova, Natalya N; Somova, Larisa M; Plekhova, Natalya G

2014-02-01

133

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

PubMed Central

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

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

2005-01-01

134

Effects of low power laser-irradiation on differential blood count and body temperature in endotoxin-preimmunized rabbits  

Microsoft Academic Search

Low power laser irradiation has been shown to have various immune-modulatory effects under in vitro conditions but little is known about such effects in animal models. Escherichia coli endotoxin-preimmunized rabbits were used to determine the influence of transcutaneously applied low power laser light on differential blood count and rectal temperature. After three initial immunizations animals were either boostered with 5

Liesbeth Schindl; Martin Schindl; Laura Polo; Giulio Jori; Sylvia Perl; Andreas Schindl

1997-01-01

135

Novel endotoxin-sequestering compounds with terephthalaldehyde-bis-guanylhydrazone scaffolds.  

PubMed

We have shown that lipopolyamines bind to the lipid A moiety of lipopolysaccharide, a constituent of Gram-negative bacterial membranes, and neutralize its toxicity in animal models of endotoxic shock. In an effort to identify non-polyamine scaffolds with similar endotoxin-recognizing features, we had observed an unusually high frequency of hits containing guanylhydrazone scaffolds in high-throughput screens. We now describe the syntheses and preliminary structure-activity relationships in a homologous series of bis-guanylhydrazone compounds decorated with hydrophobic functionalities. These first-generation compounds bind and neutralize lipopolysaccharide with a potency comparable to that of polymyxin B, a peptide antibiotic known to sequester LPS. PMID:16377188

Khownium, Kriangsak; Wood, Stewart J; Miller, Kelly A; Balakrishna, Rajalakshmi; Nguyen, Thuan B; Kimbrell, Matthew R; Georg, Gunda I; David, Sunil A

2006-03-01

136

Movement of Endotoxin Through Soil Columns  

PubMed Central

Land treatment of wastewater is an attractive alternative to conventional sewage treatment systems and is gaining widespread acceptance. Although land application systems prevent surface water pollution and augment the available water supplies, the potential dangers to human health should be evaluated. Since sewage may contain high amounts of bacterial endotoxin, the removal of endotoxin from sewage by percolation through soil was investigated. It was found that 90 to 99% of the endotoxin was removed after travel of sewage through 100 to 250 cm of loamy sand soil. When distilled water was allowed to infiltrate into the soil to simulate rainfall, the endotoxin was mobilized and moved in a concentrated band through the soil column. On testing samples from actual land treatment sites, as much as 480 ng of endotoxin per milliliter was found in some groundwater samples. The presence of endotoxin in potable water is known to be a potential problem under some circumstances, but the importance of endotoxin in water supplies has not been fully assessed. Therefore, the design, operation, and management of land application systems should take into account the fate of endotoxin in groundwater beneath the sites. PMID:7387154

Goyal, Sagar M.; Gerba, Charles P.; Lance, J. Clarence

1980-01-01

137

Detoxification of endotoxin by aluminum hydroxide adjuvant.  

PubMed

Langmuir adsorption isotherms of endotoxin and aluminum-containing adjuvants at pH 7.4 and 25 degrees C revealed that aluminum hydroxide adjuvant has a greater adsorption capacity (283 microg/mg Al) and adsorption coefficient (1.3x10(4) ml/miccrog) than aluminum phosphate adjuvant (3.0 microg/mg Al, 0.20 ml/microg). The difference in endotoxin adsorption was related to two adsorption mechanisms: electrostatic attraction and covalent bonding. The isoelectric point (iep) of endotoxin is approximately 2. An electrostatic attractive force will be present with aluminum hydroxide adjuvant (iep=11.4), and an electrostatic repulsive force will operate with aluminum phosphate adjuvant (iep=4.6). Endotoxin contains two phosphate groups in the lipid A portion. Covalent bonding occurs with surface aluminum in aluminum hydroxide adjuvant but is inhibited by surface phosphate in aluminum phosphate adjuvant. In-vitro desorption experiments using components of interstitial fluid showed that endotoxin adsorbed by aluminum hydroxide adjuvant was not desorbed by interstitial anions (5 mM phosphate or 2.7 mM citrate) or interstitial proteins (25 mg albumin/ml). The effect of aluminum-containing adjuvants on the systemic response of Sprague-Dawley rats to a 15 microg/kg subcutaneous dose of endotoxin was determined by measuring the serum concentration of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6). TNF-alpha and IL-6 were observed in the group which received an endotoxin solution or endotoxin and aluminum phosphate adjuvant. No TNF-alpha or IL-6 was detected in the group that received endotoxin and aluminum hydroxide adjuvant. Aluminum hydroxide adjuvant detoxifies endotoxin by adsorbing it in the vaccine and then not releasing it in interstitial fluid upon administration. PMID:11166900

Shi, Y; HogenEsch, H; Regnier, F E; Hem, S L

2001-02-01

138

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

Code of Federal Regulations, 2010 CFR

...false Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated...1107 Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated... The delta endotoxin of Bacillus thuringiensis variety kurstaki...

2010-07-01

139

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

Code of Federal Regulations, 2011 CFR

...false Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated...1107 Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated... The delta endotoxin of Bacillus thuringiensis variety kurstaki...

2011-07-01

140

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

...false Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated...1107 Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated... The delta endotoxin of Bacillus thuringiensis variety kurstaki...

2014-07-01

141

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

Code of Federal Regulations, 2012 CFR

...false Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated...1107 Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated... The delta endotoxin of Bacillus thuringiensis variety kurstaki...

2012-07-01

142

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

Code of Federal Regulations, 2013 CFR

...false Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated...1107 Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated... The delta endotoxin of Bacillus thuringiensis variety kurstaki...

2013-07-01

143

Exposure to endotoxin during estrus alters the timing of ovulation and hormonal concentrations in cows  

Microsoft Academic Search

The effect of intramammary (IMM) or intravenous (IV) administration of E. coli endotoxin (LPS), at the onset of estrus, at the time of ovulation was examined. Steroid and gonadotropin concentrations around ovulation were also determined. Lactating Holstein cows (n=33) were assigned to saline-controls (n=12) and treated with LPS-IV (0.5?g\\/kg; n=13) or LPS-IMM (10?g; n=8). Synchronized cows were observed continuously for

Y. Lavon; G. Leitner; T. Goshen; R. Braw-Tal; S. Jacoby; D. Wolfenson

2008-01-01

144

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. PMID:22665953

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

2012-01-01

145

Influence of in-vivo endotoxin liberation on anti-anaerobic antimicrobial efficacy.  

PubMed

The ability of cefoxitin, clindamycin, imipenem, meropenem, metronidazole and piperacillin-tazobactam to cause gram-negative anaerobic bacteria to release endotoxin and the influence of such liberated endotoxin on antibiotic efficacy were investigated in in-vivo experiments in animal models. Experimental infections in various animal models (mice, hamster and infant rats) with cultures of wild and reference strains of Bacteroides fragilis group and Fusobacterium spp. were carried out by injecting these animals with different inocula (10(6), 10(7) and 10(8) cfu/ml) of the bacterial suspension, Appropriate doses of the test antibiotics were then injected and the plasma lipopolysaccharide (endotoxin) release measured by the Limulus Amoebocyte Lysate (LAL) Assay. Evidence of worsening of the outcome of the infections post-therapy was assessed, including histopathological changes in the internal organs. Infection with generalized septicemia was established with F. nucleatum in the mice and hamster models while with the B. fragilis group, infections only led to intra-abdominal abscess formation. Plasma endotoxin release was higher in animals infected with F. nucleatum than B. fragilis and was unrelated to the bacterial inoculum. Imipenem, meropenem and cefoxitin, in that order, induced the highest levels of endotoxin activities in the animal model, particularly following F. nucleatum infection. Histological examination of the internal organs of various animals showed variation in the pattern of histopathological changes; grades 3-4 inflammatory changes in the liver were observed in the Fusobacterium-infected animals that were treated with the carbapenems and cefoxitin. Therapy with the other antibiotics did not exacerbate anaerobic sepsis. In this study, bacteremia did not lead to massive endotoxin release and antibiotic therapy appeared not to have negatively influenced the outcome of most of the gram-negative anaerobic infections, except for infections caused by Fusobacterium spp. However, it is conceivable that if the gastrointestinal tract is the source of the endotoxin in patients with systemic inflammatory response syndrome, then the obligate anaerobes like Bacteroides and Fusobacterium species, which are members of the gut flora, may play a major role in the unfavorable outcome of antibiotic therapy in some of these infections. PMID:11760215

Rotimi, V O; Al-Sweih, N N; Anim, J T; Ahmed, K; Verghese, T L; Khodakhast, F B

2001-10-01

146

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

Microsoft Academic Search

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

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

147

Early effect of low-dose endotoxin on rat cecal mucosa ex vivo.  

PubMed

It has been suggested that endotoxin triggers translocation of intestinal bacteria in vivo, either by directly damaging intestinal mucosa or by inducing a systemic inflammatory reaction that leads to mucosal disruption. To address this issue, we examined the immediate effect of extraluminal endotoxin on structure and function of isolated rat cecal mucosa without other inflammatory cells in vitro. The cecal mucosa of 12 male Wistar rats was mounted in modified Ussing chambers filled with Dulbecco's modified Eagle's medium and the ampicillin-resistant Escherichia coli HB101:K12 incubated on the mucosal side. Endotoxin was added to the submucosal side at concentrations of 1 and 10 EU/ml, respectively. Under gassing with carbogene at 37 degreesC, the potential difference across the mucosa was measured continuously. Samples of the mucosal and submucosal solutions were removed at 60, 120, and 180 min and plated out on McConkey ampicillin-agar. After 180 min, the mucosal specimens were retrieved and examined by light and scanning electron microscopy. No significant change in potential difference was observed in control or endotoxin-incubated mucosa within the observation period. Neither light nor scanning electron microscopy showed a significant change in the structure of the epithelium, mucosa, or submucosa. No significant translocation of the E. coli across the mucosa was seen. We concluded that endotoxin alone does not induce immediate structural and functional damage to rat cecal mucosa in vitro. Therefore, it seems unlikely that a short endotoxemia alone directly triggers bacterial translocation by disrupting intestinal mucosa, but rather, entotoxin induces a local and systemic inflammatory reaction that leads to mucosal disruption. PMID:9878322

Mayer, J M; Dolch, M; Rozdzinski, E; Schoenberg, M H; Beger, H G

1998-12-01

148

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

PubMed

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

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

2015-02-01

149

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

PubMed Central

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

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

2013-01-01

150

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

2002-01-01

151

Lipopolysaccharide induces oxidative cardiac mitochondrial damage and biogenesis  

Microsoft Academic Search

Abstract Objective: The responses to bacterial lipopolysaccharide (LPS) damage,mitochondria by generating oxidative stress within the organelles. We postulated that LPS damages heart mitochondrial DNA and protein by oxidation, and that this is recovered by oxidative mechanisms of mitochondrial biogenesis. Methods and results: Systemic crude E. coli LPS administration decreased mtDNA copy number,and mtDNA gene transcription in rat heart caused by

Hagir B. Suliman; Karen E. Welty-Wolf; Martha Sue Carraway; Lynn Tatro; Claude A. Piantadosi

152

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

PubMed

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

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

2015-05-15

153

Lipopolysaccharides of Salmonella T Mutants  

PubMed Central

The composition of lipopolysaccharides derived from various Salmonella T forms was studied. All T1-form lipopolysaccharides examined contained 14 to 22% each of both d-galactose and pentose in addition to 4 to 9% each of ketodeoxyoctonic acid, heptose, d-glucosamine, and d-glucose. The pentose was identified as d-ribose. The T2-form lipopolysaccharide examined did not contain a significant amount of pentose, nor more than the usual amounts of d-galactose. Periodate oxidation of T1 (lipo) polysaccharides followed by NaBH4 reduction revealed that ribose was almost quantitatively protected, galactose was destroyed, and threitol and mannose were newly formed. The latter two products probably originated from 4-linked galactose and heptose, respectively. Ribose and galactose were found in specific precipitates of T1 lipopolysaccharide with anti-T1 antiserum but were not found in specific precipitates of alkali-treated T1 lipopolysaccharide and of Freeman degraded polysaccharide with anti-T1 serum Ribose and galactose are present in these degraded preparations in the form of nondialyzable polymers. The T1-form mutant lipopolysaccharides lacked the O-specific sugars constituting the side-chains in the wild-type antigens. They did not produce the soluble O-specific haptenic polysaccharide known to be accumulated in RI strains. With these properties, T1 lipopolysaccharides resemble RII lipopolysaccharides. Like RII degraded polysaccharides, T1-degraded polysaccharides also contained glucosamine. Furthermore, strong cross-reactions were found to exist between T1 and RII lipopolysaccharides in both hemagglutination inhibition assays and in precipitation tests. It is proposed that T1 lipopolysaccharides represent RII lipopolysaccharides to which polymers consisting of ribose and galactose are attached. PMID:6057795

Wheat, R. W.; Berst, M.; Ruschmann, E.; Lüderitz, O.; Westphal, O.

1967-01-01

154

Synchronous Recruitment of Epigenetic Modifiers to Endotoxin Synergistically Activated Tnf-? Gene in Acute Kidney Injury  

PubMed Central

Background As a consequence of acute kidney injury (AKI), proximal tubular cells hyperrespond to endotoxin (lipopolysaccharide, LPS) by exaggerated renal Tnf-? Production. This LPS hyperresponsiveness is transcriptionally mediated. The epigenetic pathways that control these responses are unknown. Methods/Findings We applied multiplex chromatin immunoprecipitation platform (Matrix ChIP) to explore epigenetic pathways that underlie endotoxin hyperresponsiveness in the setting of preceding unilateral renal ischemia/reperfusion (I/R) in mouse AKI model. Endotoxin exposure after I/R resulted in enhanced transcription, manifested by hyperresponsive recruitment of RNA polymerase II (Pol II) at the Tnf-? gene. At this locus, LPS but not I/R increased levels of Pol II C-terminal domain (CTD) phosho-serine2 &5 and induced dephosphorylation of the transcription-repressive histone H4 phospho-serine-1. In contrast, I/R but not LPS increased the transcription-permissive histone phosphorylation (H3 phospho-serine-10, H3.3 phospho-serine-31) at the Tnf-? gene. In agreement with these observations, I/R but not LPS increased activity of cognate kinases (Erk1/2, Msk1/2 and Aurora A) at the Tnf-? locus. Cross-talk of histone phosphorylation and acetylation synergize to active gene expression. I/R and LPS increased histone acetylation. (H3K9/14Ac, H4K5/8/12/16Ac, H2KA5Ac, H2BK4/7Ac). Levels of some histone acetyltransferases at this gene (PCAF and MOF) were increased by I/R but not by LPS, while others were induced by either I/R or LPS and exhibited endotoxin hyperresponsive patterns (GCN5, CBP and p300). The adaptor protein 14-3-3 couples histone phosphorylation with acetylation, and tethers chromatin modifiers/transcription elongation factors to target genes. Both I/R and LPS increased levels of 14-3-3 and several chromatin/transcription modifiers (BRD4, BRG1, HP-1? and IKK?) at the Tnf-? gene, all exhibiting endotoxin hyperresponsive recruitment patterns similar to Pol II. Conclusions Our results suggest that I/R and LPS differentially trigger phosphorylation (Pol II and histone) and acetylation (histone) epigenetic pathways that interact at the Tnf-? gene to generate endotoxin hyperresponse in AKI. PMID:23936185

Bomsztyk, Karol; Flanagin, Steve; Mar, Daniel; Mikula, Michal; Johnson, Ali; Zager, Richard; Denisenko, Oleg

2013-01-01

155

Resurrecting Inactive Antimicrobial Peptides from the Lipopolysaccharide Trap  

PubMed Central

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

Mohanram, Harini

2014-01-01

156

Histochemical evidence for lipid A (endotoxin) in eukaryote chloroplasts.  

PubMed

Lipopolysaccharide (LPS) (a.k.a., endotoxin) is an essential component of the outer leaflet of the outer membrane of gram-negative bacteria and is a potent activator of the innate immune system of animals. Lipid A, the glycolipid core of LPS, is the agent responsible for disease and death from gram-negative sepsis, an important cause of human mortality and morbidity. Although it is generally accepted that lipid A is restricted to the prokaryotes, recent efforts to purify molecules from green algae with structural features unique to lipid A have met with success. Furthermore, the vascular plant Arabidopsis thaliana has been found to contain genes that encode all of the enzymes of the biosynthetic pathway for lipid A. It is not known whether vascular plants synthesize lipid A or where lipid A might be located in the tissues. For the present study, we used affinity reagents for lipid A to probe green alga and tissues of the garden pea for a light microscopic localization of lipid A in these eukaryote cells. We find staining for lipid A in free-living and endosymbiotic green algae and in the chloroplasts of vascular plants, indicating that this molecule is not restricted to prokaryotes, but is found also in select eukaryotes. PMID:16935939

Armstrong, Margaret T; Theg, Steven M; Braun, Nikolai; Wainwright, Norman; Pardy, R L; Armstrong, Peter B

2006-10-01

157

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

PubMed Central

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

Loosbroock, Christopher; Hunter, Kenneth W

2014-01-01

158

High-affinity binding of the bactericidal/permeability-increasing protein and a recombinant amino-terminal fragment to the lipid A region of lipopolysaccharide.  

PubMed Central

Bactericidal/permeability-increasing protein (BPI) is a 55-kDa cationic protein (nBPI55) elaborated by polymorphonuclear neutrophils (PMN). BPI has potent bactericidal activity against a wide variety of gram-negative organisms and neutralizes endotoxin activities. An N-terminal fragment of nBPI55 exhibits the bactericidal and antiendotoxin properties of the holoprotein. To further characterize the biological activities of the N-terminal fragment, a recombinant protein (rBPI23) corresponding to the first 199 amino acids of human BPI was produced and purified. rBPI23 had antibacterial activity equivalent to that of nBPI55 against Escherichia coli J5. Furthermore, both rBPI23 and nBPI55 bound identically to a broad range of R- and S-form lipopolysaccharides (LPS) and to natural and synthetic lipid A. Binding of radiolabeled nBPI55 to LPS was inhibited in an identical fashion by either nBPI55 or rBPI23. The binding of both proteins to immobilized E. coli J5 lipid A was inhibited in a comparable fashion by long- or short-chain LPS or lipid A. The binding of both rBPI23 and nBPI55 was specific, saturable, and of high affinity, with an apparent Kd of approximately 2 to 5 nM for all ligands tested. These results demonstrate that BPI recognizes the highly conserved lipid A region of bacterial LPS via residues contained within the amino-terminal portion of the BPI molecule. Images PMID:1398985

Gazzano-Santoro, H; Parent, J B; Grinna, L; Horwitz, A; Parsons, T; Theofan, G; Elsbach, P; Weiss, J; Conlon, P J

1992-01-01

159

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. 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.

2011-01-01

160

Studies with Radioactive Endotoxin II. Clearance of 3H-Labelled Endotoxin from the Blood of Calves  

PubMed Central

The clearance of 3H-labelled Pseudomonas endotoxin from the blood was studied in a nontolerant and in an endotoxin tolerant state. Calves were rendered tolerant to the toxic effects of the endotoxin by four daily intravenous injections of endotoxin at the dose rate of 5 µg/kg body weight. Clearance of 3H-endotoxin from the blood of nontolerant calves occurred more slowly than did clearance of 51Cr-endotoxin and was not significantly (P<0.05) affected by the development of tolerance. The lungs and liver were the major organs involved in the clearance of 3H-endotoxin from the blood of calves. Leukocytes and erythrocytes, but not platelets, were shown to participate in endotoxin clearance in calves. 3H2O, the control substance used in calves, was not concentrated within any particular organ but rapidly equilibrated with total body water and was slowly excreted. PMID:4279755

Maxie, M. G.; Valli, V. E. O.; Lumsden, J. H.

1974-01-01

161

Immunization with Lipopolysaccharide-Deficient Whole Cells Provides Protective Immunity in an Experimental Mouse Model of Acinetobacter baumannii Infection  

PubMed Central

The increasing clinical importance of infections caused by multidrug resistant Acinetobacter baumannii warrants the development of novel approaches for prevention and treatment. In this context, vaccination of certain patient populations may contribute to reducing the morbidity and mortality caused by this pathogen. Vaccines against Gram-negative bacteria based on inactivated bacterial cells are highly immunogenic and have been shown to produce protective immunity against a number of bacterial species. However, the high endotoxin levels present in these vaccines due to the presence of lipopolysaccharide complicates their use in human vaccination. In the present study, we used a laboratory-derived strain of A. baumannii that completely lacks lipopolysaccharide due to a mutation in the lpxD gene (IB010), one of the genes involved in the first steps of lipopolysaccharide biosynthesis, for vaccination. We demonstrate that IB010 has greatly reduced endotoxin content (<1.0 endotoxin unit/106 cells) compared to wild type cells. Immunization with formalin inactivated IB010 produced a robust antibody response consisting of both IgG1 and IgG2c subtypes. Mice immunized with IB010 had significantly lower post-infection tissue bacterial loads and significantly lower serum levels of the pro-inflammatory cytokines IL-1?, TNF-? and IL-6 compared to control mice in a mouse model of disseminated A. baumannii infection. Importantly, immunized mice were protected from infection with the ATCC 19606 strain and an A. baumannii clinical isolate. These data suggest that immunization with inactivated A. baumannii whole cells deficient in lipopolysaccharide could serve as the basis for a vaccine for the prevention of infection caused by A. baumannii. PMID:25485716

García-Quintanilla, Meritxell; Pulido, Marina R.; Pachón, Jerónimo; McConnell, Michael J.

2014-01-01

162

Application of quartz tuning forks for detection of endotoxins and Gram-negative bacterial cells by monitoring of Limulus Amebocyte Lysate coagulation.  

PubMed

Endotoxins, pyrogens of bacterial origin, are a significant threat in many areas of life. Currently, the test most commonly used for endotoxin level determination is LAL (Limulus Amebocyte Lysate) assay. This paper presents application of commercially available low-frequency piezoelectric tuning forks (QTFs) for endotoxin detection. Measurement of the decrease in the QTF oscillation amplitude provides information about the viscosity changes, occurring in the tested sample upon addition of LAL. That method was used to determine the concentrations of endotoxins and bacterial cells (E. coli O157:H19). The relevance of the obtained results was confirmed using a commercially available colorimetric LAL assay. The constructed system can detect bacterial endotoxins in the range of 0.001-5EU/ml and bacterial cells in the range of 10(2)-10(7)CFU/ml. The presented technique requires very simple sample preparation and the sensor response is obtained using compact, portable readout electronics. The single test cost is low compared to commercial endotoxin assays and other novel systems based on micromechanical sensors. PMID:24632139

Cha?upniak, Andrzej; Waszczuk, Karol; Ha?ubek-G?uchowska, Katarzyna; Piasecki, Tomasz; Gotszalk, Teodor; Rybka, Jacek

2014-08-15

163

Longitudinal study of dust and airborne endotoxin in the home.  

PubMed Central

To characterize the seasonal variability of endotoxin levels, we measured endotoxin in dust from the bed, bedroom floor, and kitchen floor in 20 homes, and in air from the bedroom in 15 of the homes. All homes were located in the greater Boston, Massachusetts, area and were sampled each month from April 1995 to June 1996. Outdoor air was collected at two locations. We found greater within-home than between-home variance for bedroom floor, kitchen floor, and airborne endotoxin. However, the reverse was true for bed dust endotoxin. Thus, studies using single measurements of dust endotoxin are most likely to reliably distinguish between homes if bed dust is sampled. Dust endotoxin levels were not significantly associated with airborne endotoxin. Airborne endotoxin was significantly (p = 0. 04) and positively associated with absolute humidity in a mixed-effect model adjusting for a random home effect and fixed effect of sampling month and home characteristics. This finding implies that indoor humidity may be an important factor controlling endotoxin exposure. We found a significant (p < 0.05) seasonal effect in kitchen floor dust (spring > fall) and bedroom airborne endotoxin (spring > winter), but not in the other indoor samples. We found significant seasonal pattern in outdoor airborne endotoxin (summer > winter). PMID:11102291

Park, J H; Spiegelman, D L; Burge, H A; Gold, D R; Chew, G L; Milton, D K

2000-01-01

164

Allantoin as a solid phase adsorbent for removing endotoxins.  

PubMed

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

2013-10-01

165

Quantitative determination of endotoxins released by bacterial biofilms.  

PubMed

Residual endotoxins, commonly associated with bacterial biofilms colonizing reusable medical devices have been associated with pyrogenic reactions in patients. We have used a quantitative, sensitive and reproducible kinetic chromogenic adaptation of the Limulus Amebocyte Lysate assay to assess endotoxin recovery from an in-vitro bacterial biofilm. The 'recovery method' was based on a combination of physical treatment (vortexing and sonication) and chemical treatment (immersion in recovery solution). Five recovery solutions were investigated. The recovered endotoxin was greater when the biofilm was treated with a 1% SDS solution. The sensitive and reproducible method we have developed should allow the recovery and measurement of biofilm bacterial endotoxins on implanted and colonized medical devices. Moreover, the amount of endotoxin was sufficient (> 1000 endotoxin units/cm2 of substrate) to enable a substantial reduction by sterilization processes, the efficiency of which on biofilm endotoxins has yet to be proven. PMID:10582187

Rioufol, C; Devys, C; Meunier, G; Perraud, M; Goullet, D

1999-11-01

166

Induction of innate immune responses by Escherichia coli and purified lipopolysaccharide correlate with organ- and cell-specific expression of Toll-like receptors within the human urinary tract.  

PubMed

Mucosal epithelial linings function as physical barriers against microbes. In addition, they participate in the first line of host defence by production of a variety of proinflammatory mediators when exposed to microbes and microbial agents. Here, we use a human urinary tract infection model to demonstrate that organ- and cell-specific innate responses induced by lipopolysaccharides (LPS) present on Gram-negative bacteria correlates with the expression of Toll-like receptor 4 (TLR4). The presence of TLR4 on human bladder epithelial cells enables them to rapidly respond to bacterial infections in vitro and in vivo. In contrast, TLR4 is not expressed on human proximal tubule cells isolated from the renal cortex, which may explain the cortical localization of bacteria in pyelonephritis. TLR4-negative renal epithelial cells, A498, are non-responsive to purified LPS, however, they respond to viable bacteria via a mannose-sensitive attachment-mediated pathway. To identify LPS components recognised by bladder epithelial cells, a bacterial lipid A mutant and LPS of different chemotypes were tested. Full interleukin 8 induction required hexa-acylated lipid A and was decreased by between 50% and 70% in the presence of O-antigen. Taken together, we propose that multiple independent pathways, which are organ- and cell-specifically expressed, mediate bacterial recognition and determine the outcome of innate responses to infection. PMID:11260138

Bäckhed, F; Söderhäll, M; Ekman, P; Normark, S; Richter-Dahlfors, A

2001-03-01

167

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

168

Effect of Sodium Butyrate on Growth Performance and Response to Lipopolysaccharide in Weanling Pigs  

Technology Transfer Automated Retrieval System (TEKTRAN)

Two experiments were conducted to determine the effects of dietary sodium butyrate on growth performance and response to E. coli. lipopolysaccharide (LPS) in weanling pigs. In the first 28 d experiment, 180 pigs (initial BW 6.3 kg) were fed 0, 0.05, 0.1, 0.2, and 0.4% sodium butyrate, or 110 mg/kg d...

169

COX-2 mediated induction of endothelium-independent contraction to bradykinin in endotoxin-treated porcine coronary artery.  

PubMed

This study examined the vascular effects of bradykinin in health and vascular inflammation comparing responses of isolated pig coronary arteries in the absence and presence of endotoxins. Bradykinin induced contractions in lipopolysaccharide-treated, but not untreated, arterial rings without endothelium. The B2-receptor antagonist HOE140, but not the B1-receptor inhibitor SSR240612, blocked these endothelium-independent contractions in response to bradykinin. The bradykinin-induced contractions were blocked by indomethacin, celecoxib, and terbogrel but not valeryl salicylate, AH6809, AL 8810, or RO1138452. They were attenuated by N-(p-amylcinnamoyl) anthranilic acid, and by diethyldithiocarbamate plus tiron but not by L-NAME. Quantitative reverse-transcription polymerase chain reaction revealed significant upregulations of messenger RNA expressions of B1 receptors, COX-2, and thromboxane A synthase 1 (TBXAS1) following lipopolysaccharide incubation but not of B2 receptors or COX-1. The present data demonstrate that bradykinin induces contractions mediated by the COX-2 pathway in endotoxin-treated pig coronary arteries. These results support differential roles of bradykinin in health and disease. PMID:25192543

More, Amar S; Kim, Hye Min; Zhao, Ru; Khang, Gilson; Hildebrandt, Tobias; Bernlöhr, Christian; Doods, Henri; Lee, Dongwon; Lee, Seung Hee; Vanhoutte, Paul M; Wu, Dongmei

2014-09-01

170

Generation of minicells from an endotoxin-free gram positive strain Corynebacterium glutamicum.  

PubMed

Drug delivery systems (DDSs) incorporating bacterial minicells have been evaluated as a very powerful tool in view of biocompatibility. However, limited studies have been carried out on these systems, mainly using minicells from Salmonella sp. and Escherichia coli. Thus, we generated a new minicell-producing strain from an endotoxin-free Corynebacterium glutamicum by the inactivation of genes related to cell division. The two knock-out strains, ?parA and ?ncgl1366, showed distinct abilities to produce minicells. The resulting minicells were purified via sequential antibiotic treatments and centrifugations, which resulted in reproducible yield. PMID:25341464

Lee, Jin-Young; Choy, Hyon E; Lee, Jin-Ho; Kim, Geun-Joong

2014-10-23

171

Lipopolysaccharides in diazotrophic bacteria.  

PubMed

Biological nitrogen fixation (BNF) is a process in which the atmospheric nitrogen (N2) is transformed into ammonia (NH3) by a select group of nitrogen-fixing organisms, or diazotrophic bacteria. In order to furnish the biologically useful nitrogen to plants, these bacteria must be in constant molecular communication with their host plants. Some of these molecular plant-microbe interactions are very specific, resulting in a symbiotic relationship between the diazotroph and the host. Others are found between associative diazotrophs and plants, resulting in plant infection and colonization of internal tissues. Independent of the type of ecological interaction, glycans, and glycoconjugates produced by these bacteria play an important role in the molecular communication prior and during colonization. Even though exopolysaccharides (EPS) and lipochitooligosaccharides (LCO) produced by diazotrophic bacteria and released onto the environment have their importance in the microbe-plant interaction, it is the lipopolysaccharides (LPS), anchored on the external membrane of these bacteria, that mediates the direct contact of the diazotroph with the host cells. These molecules are extremely variable among the several species of nitrogen fixing-bacteria, and there are evidences of the mechanisms of infection being closely related to their structure. PMID:25232535

Serrato, Rodrigo V

2014-01-01

172

Rutin improves endotoxin-induced acute lung injury via inhibition of iNOS and VCAM-1 expression.  

PubMed

Endotoxins exist anywhere including in water pools, dust, humidifier systems, and machining fluids. The major causal factor is endotoxins in many serious diseases, such as fever, sepsis, multi-organ failure, meningococcemia, and severe morbidities like neurologic disability, or hearing loss. Endotoxins are also called lipopolysaccharide (LPS) and are important pathogens of acute lung injury (ALI). Rutin has potential beneficial effects including anti-inflammation, antioxidation, anti-hyperlipidemia, and anti-platelet aggregation. Pre-treatment with rutin inhibited LPS-induced neutrophil infiltration in the lungs. LPS-induced expression of vascular cell adhesion molecule (VCAM)-1 and inducible nitric oxide synthase (iNOS) was suppressed by rutin, but there was no influence on expression of intercellular adhesion molecule-1 and cyclooxygenase-2. In addition, activation of the nuclear factor (NF)?B was reduced by rutin. Furthermore, we found that the inhibitory concentration of rutin on expression of VCAM-1 and iNOS was similar to NF?B activation. In conclusion, rutin is a potential protective agent for ALI via inhibition of neutrophil infiltration, expression of VCAM-1 and iNOS, and NF?B activation. © 2014 Wiley Periodicals, Inc. Environ Toxicol, 2014. PMID:25080890

Huang, Yi-Chun; Horng, Chi-Ting; Chen, Shyan-Tarng; Lee, Shiuan-Shinn; Yang, Ming-Ling; Lee, Chien-Ying; Kuo, Wu-Hsien; Yeh, Chung-Hsin; Kuan, Yu-Hsiang

2014-08-01

173

The effect of taurine on the relationship between NO, ADMA and homocysteine in endotoxin-mediated inflammation in HUVEC cultures.  

PubMed

The aim of our study was to investigate the effect of taurine on the relationship between nitric oxide (NO), asymmetric dimethylarginine (ADMA) and homocysteine (Hcy) in endotoxin-induced human umblical vein endothelial cell (HUVEC) cultures. For this reason, four groups were formed (n=12). Control group consists of HUVEC cultures without any treatment. Lipopolysaccharide (LPS) and LPS+taurine groups were treated with 10 ?g/mL endotoxin, 5 ?g/mL taurine and endotoxin+taurine (same doses), respectively. Nitrite/nitrate (NOx), ADMA and Hcy levels were measured. There was a significant increase of NOx, ADMA and Hcy in endotoxemia (p<0.05). Taurine treatment elevated NOx levels significantly (p<0.01) in taurine and LPS?+?taurine group compared to control group, while it reduced NOx levels compared to LPS group. In contrast, taurine decreased ADMA levels to the control level both in taurine and taurine+LPS group compared to LPS. Hcy levels increased significantly compared to taurine group (p<0.05) and did not change compared to LPS group. Taurine was effective on ADMA-NO relationship whereas no beneficial effect was observed in Hcy levels (p<0.05). PMID:24604342

Pasaoglu, Ozge Tugce; Turkozkan, Nurten; Ark, Mustafa; Polat, Belgin; Agilli, Mehmet; Yaman, Halil

2014-10-01

174

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

PubMed

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

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

2014-05-01

175

De novo designed lipopolysaccharide binding peptides: structure based development of antiendotoxic and antimicrobial drugs.  

PubMed

Lipopolysaccharide (LPS), the glycolipid of the outer membrane of Gram-negative bacteria, is critically involved in health and diseases. LPS facilitates the survival of pathogens by imposing a permeability barrier against antibiotics and antimicrobial peptides. LPS, also termed as endotoxin, functions as a potent inducer of innate immunity. Interception of endotoxin in systemic circulation by immune cells e.g. macrophages is essential to mount surveillance against invading microbes. However, a hyper-activated immune response may lead to the overwhelming production of tissue damaging cytokines TNF-?, IL-1, IL-6 and free radicals that may cause multiple organ failures or septic shock syndromes. The sepsis or septic shock is the major cause of mortality; 120,000 deaths/year occur in the United States alone, in the intensive care units. To-date, no therapeutic is available to combat sepsis mediated lethality. Furthermore, bacterial resistance against commonly used antibiotics has been increasing at an alarming rate necessitating a search for antibacterial agents with novel mode of actions. LPS could be a valid drug target for the development of antiendotoxic and antimicrobial compounds. In this article, recent advances in structural basis of LPS recognition by its receptor proteins and mode of actions of antimicrobial peptides defensins and cathelicidins are reviewed. Our research has identified, through de novo design, antimicrobial and endotoxin interacting ?-boomerang peptides. Structure-activity correlations (SAR) of these peptides have been discussed, highlighting future design to achieve potent LPS neutralizing molecules. PMID:20629624

Bhattacharjya, S

2010-01-01

176

LPS-conditioned dendritic cells confer endotoxin tolerance contingent on tryptophan catabolism.  

PubMed

Dendritic cells (DCs) are specialized antigen-presenting cells with a bipolar nature. Depending on environmental factors, DCs will promote either inflammatory or anti-inflammatory effects. Lipopolysaccharide (LPS), a ligand of Toll-like receptor (TLR)4 and a most potent proinflammatory stimulus, is responsible for complex signaling events in different cell types, including DCs. LPS effects range from protective inflammation-capable of counteracting growth and dissemination of gram-negative bacteria - to hyperacute detrimental responses, as it occurs in endotoxic shock. Consistent with the plasticity of TLR4 signaling, a low dosage of LPS will induce a regulatory response capable of protecting mice against a subsequent, otherwise lethal challenge ('endotoxin tolerance'). By examining CD11c(+) DCs ('conventional' DCs, or cDCs), we investigated whether DC flexibility in promoting either inflammation or tolerance can be differentially affected by single vs. repeated exposure to LPS in vitro. cDCs stimulated twice with LPS expressed high levels of indoleamine 2,3-dioxygenase 1 (IDO1) - one of the most effective mediator of anti-inflammatory activity by DCs - and of TGF-?, an immunoregulatory cytokine capable of upregulating IDO1 expression and function. In contrast, a single exposure to LPS failed to upregulate IDO1, and it was instead associated with high-level production of IL-6, a cytokine that promotes inflammation and proteolysis of IDO1. When adoptively transferred in vivo, only cDCs on double endotoxin exposure greatly improved the outcome of an otherwise lethal LPS challenge. The protective effect required that the transferred cDCs be fully competent for IDO1 and the host for TGF-? production. Thus cDCs, conditioned by LPS in vitro to mimic an endotoxin-tolerant state, can protect recipients from endotoxic shock, pointing to adoptive transfer of tolerance as a new option for controlling potentially harmful responses to TLR4 signaling. PMID:25278421

Fallarino, Francesca; Pallotta, Maria T; Matino, Davide; Gargaro, Marco; Orabona, Ciriana; Vacca, Carmine; Mondanelli, Giada; Allegrucci, Massimo; Boon, Louis; Romani, Rita; Talesa, Vincenzo N; Puccetti, Paolo; Grohmann, Ursula

2015-02-01

177

Protective effects of inhaled carbon monoxide in endotoxin-induced cholestasis is dependent on its kinetics.  

PubMed

Carbon monoxide (CO), a product of heme oxygenase (HMOX), has many beneficial biological functions and is a promising therapeutic agent for many pathological conditions. However, the kinetics of inhaled CO and its protective role in endotoxin-induced cholestasis is not fully known. Thus, our objective was to characterize the kinetics of inhaled CO and then investigate its use in early phase experimental endotoxin-induced cholestasis. Female Wistar rats were randomly divided into 4 groups: CON (control), LPS (lipopolysaccharide, 6 mg/kg), CO (250 ppm COx1h), and CO + LPS. Rats were sacrificed at 0-12 h after LPS administration. Tissues and blood were collected for liver injury markers and tissue CO distribution measurements. Livers were harvested for measurements of Hmox activity, Hmox1 mRNA expression, cytokines (IL10, IL6, TNF), and bile lipid and pigment transporters. Half-lives of CO in spleen, blood, heart, brain, kidney, liver, and lungs were 2.4 ± 1.5, 2.3 ± 0.8, 1.8 ± 1.6, 1.5 ± 1.2, 1.1 ± 1.1, 0.6 ± 0.3, 0.6 ± 0.2 h, respectively. CO treatment increased liver IL10 mRNA and decreased TNF expression 1 h after LPS treatment and prevented the down-regulation of bile acid and bilirubin hepatic transporters (Slc10a1, Abcb11, and Abcc2, p < 0.05), an effect closely related to the kinetics. The protective effect of CO against cholestatic liver injury persisted even 12 h after CO exposure, as shown by attenuation of serum cholestatic markers in CO-treated animals. CO exposure substantially attenuated endotoxin-induced cholestatic liver injury and was directly related to the kinetics of inhaled CO. This data underscores the importance of the kinetics of inhaled CO for the proper design of experimental and clinical studies of using CO as a treatment strategy. PMID:24148277

Vanova, K; Suk, J; Petr, T; Cerny, D; Slanar, O; Vreman, H J; Wong, R J; Zima, T; Vitek, L; Muchova, L

2014-02-01

178

Monocytes from Depressed Patients Display an Altered Pattern of Response to Endotoxin Challenge  

PubMed Central

It is now well established that major depression is accompanied and characterized by altered responses of the immune-inflammatory system. In this study we investigated the pro-inflammatory activation of monocytes isolated from depressed patients as a parameter not influenced by such confounds as the time of day, the nutritional and exercise status or the age and gender of patients. Monocytes from depressed patients and from healthy controls were isolated in vitro; after 24-h incubation under basal conditions, cells were exposed for 24-h to 100 ng/ml of endotoxin (bacterial lipopolysaccharide, LPS). We found that monocytes from drug-free depressed patients and controls release the same amounts of prostaglandin E2 (PGE2) under basal conditions, whereas monocytes from patients are dramatically less reactive to LPS (8.62-fold increase vs previous 24 hrs) compared to healthy controls (123.3-fold increase vs previous 24 hrs). Such blunted prostanoid production was paralleled by a reduction in COX-2 gene expression, whereas other pro-inflammatory mediators, namely interleukin-1? (IL-1 ?) and -6 (IL-6) showed a trend to increased gene expression. The above changes were not associated to increased levels of circulating glucocorticoids. After 8 months of antidepressive drug treatment, the increase in PGE2 production after the endotoxin challenge was partially restored, whereas the increase in IL-1 ? and -6 levels observed at baseline was completely abolished. In conclusion, our findings show that the reactivity of monocytes from depressed patients might be considered as a marker of the immune-inflammatory disorders associated to depression, although the lack of paired healthy controls at follow-up does not allow to conclude that monocyte reactivity to endotoxin is also a marker of treatment outcome. PMID:23300980

Lisi, Lucia; Camardese, Giovanni; Treglia, Mariangela; Tringali, Giuseppe; Carrozza, Cinzia; Janiri, Luigi; Russo, Cinzia Dello; Navarra, Pierluigi

2013-01-01

179

Angiotensin II Inhibitor DuP753 Attenuates Burn- and Endotoxin-Induced Gut Ischemia, Lipid Peroxidation, Mucosal Permeability, and Bacterial Translocation  

PubMed Central

Objective To investigate the role of angiotensin II as a mediator of burn- and sepsis-induced gut ischemia and reperfusion injury and to determine whether treatment with the angiotensin II inhibitor DuP753 can attenuate mucosal injury and bacterial translocation in a burn/endotoxemia porcine model. Summary Background Data Thermal injuries and endotoxemia have been shown to induce ischemia and reperfusion injury to the intestine, leading to increased mucosal permeability and bacterial translocation. Angiotensin II, the production of which has been reported to increase after burn, is thought to be one of the primary mediators of postburn mesenteric vasoconstriction. Methods An ultrasonic flow probe was inserted into the superior mesenteric artery and a catheter into the superior mesenteric vein in 21 female pigs. After 5 days, all animals were anesthetized, and 14 received 40% total body surface area third-degree burn. DuP753 was administered intravenously at 1 ?g/kg to seven pigs immediately after burn. Eighteen hours after burn, 100 ?g/kg Escherichia coli lipopolysaccharide (LPS) was intravenously administered. Systemic and splanchnic hemodynamics were measured and blood samples were drawn for blood gas analysis. Plasma conjugated dienes (PCDs), an index of lipid peroxidation, were measured every 6 hours. Intestinal permeability was assessed every 6 hours by measuring the lactulose/mannitol excretion ratio. At the end of the study (42 hours), tissue samples were harvested for bacteriologic cultures. Results Burn caused a significant decrease in mesenteric blood flow, to approximately 58% of baseline. Postburn endotoxemia significantly reduced the blood flow in the superior mesenteric artery to 53% of baseline. Treatment with DuP753 prevented postburn vasoconstriction and subsequently abrogated the impact of postburn endotoxemia on blood flow in the superior mesenteric artery. Mesenteric oxygen supply was significantly reduced after burn and endotoxin to 60% and 51% of baseline levels, respectively. DuP753 administration significantly improved mesenteric oxygen supply after both insults. Burn- and LPS-induced mesenteric hypoxia, as indicated by decreased mesenteric oxygen consumption, was also ameliorated by DuP753 treatment. PCD levels were significantly elevated 8 hours after burn. LPS caused a higher and prolonged increase in PCD levels. Treatment with DuP753 significantly reduced PCD levels after burn and after LPS. Intestinal permeability, as assessed by the lactulose/mannitol ratio, showed 6-fold and 12-fold increases after thermal injury and LPS, respectively. In contrast, the lactulose/mannitol ratio was only doubled in DuP753-treated animals. Bacterial translocation was significantly increased after burn and endotoxin. The incidence of bacterial translocation in the DuP753-treated animals was similar to that in the sham group. Conclusions Angiotensin II appears to play a pivotal role in the burn- and endotoxin-induced intestinal ischemia and reperfusion injury, with subsequent increases in permeability and bacterial translocation. Postburn administration of the angiotensin II receptor antagonist DuP753 significantly reduces the extent of these events. PMID:10749619

Tadros, Tamer; Traber, Daniel L.; Heggers, J. P.; Herndon, David N.

2000-01-01

180

Endotoxin-induced myocardial dysfunction in senescent rats  

PubMed Central

Introduction Aging is associated with a decline in cardiac contractility and altered immune function. The aim of this study was to determine whether aging alters endotoxin-induced myocardial dysfunction. Methods Senescent (24 month) and young adult (3 month) male Wistar rats were treated with intravenous lipopolysaccharide (LPS) (0.5 mg/kg (senescent and young rats) or 5 mg/kg (young rats only)), or saline (senescent and young control groups). Twelve hours after injection, cardiac contractility (isolated perfused hearts), myofilament Ca2+ sensitivity (skinned fibers), left ventricular nitric oxide end-oxidation products (NOx and NO2) and markers of oxidative stress (thiobarbituric acid reactive species (TBARS) and antioxidant enzymes) were investigated. Results LPS (0.5 mg/kg) administration resulted in decreased contractility in senescent rats (left ventricular developed pressure (LVDP), 25 ± 4 vs 53 ± 4 mmHg/g heart weight in control; P < 0.05) of amplitude similar to that in young rats with LPS 5 mg/kg (LVDP, 48 ± 7 vs 100 ± 7 mmHg/g heart weight in control; P < 0.05). In contrast to young LPS rats (0.5 and 5 mg/kg LPS), myofilament Ca2+ sensitivity was unaltered in senescent LPS hearts. Myocardial NOx and NO2 were increased in a similar fashion by LPS in young (both LPS doses) and senescent rats. TBARS and antioxidant enzyme activities were unaltered by sepsis whatever the age of animals. Conclusion Low dose of LPS induced a severe myocardial dysfunction in senescent rats. Ca2+ myofilament responsiveness, which is typically reduced in myocardium of young adult septic rats, however, was unaltered in senescent rats. If these results are confirmed in in vivo conditions, they may provide a cellular explanation for the divergent reports on ventricular diastolic function in septic shock. In addition, Ca2+-sensitizing agents may not be as effective in aged subjects as in younger subjects. PMID:16942612

Rozenberg, Sandrine; Besse, Sophie; Brisson, Hélčne; Jozefowicz, Elsa; Kandoussi, Abdelmejid; Mebazaa, Alexandre; Riou, Bruno; Vallet, Benoît; Tavernier, Benoît

2006-01-01

181

Diet-induced obesity attenuates endotoxin-induced cognitive deficits.  

PubMed

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

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

2015-03-15

182

Bupropion pre-treatment of endotoxin-induced depressive symptoms.  

PubMed

Increased levels of inflammatory cytokines may play a role in depression. Depressive symptoms can be induced in humans with administration of low-dose lipopolysaccharide (LPS; endotoxin), which activates the innate immune system and causes release of inflammatory cytokines. We previously found that pre-treatment with the serotonin reuptake inhibitor citalopram reduced LPS-induced fatigue and anhedonia. This is a follow-up study to determine whether LPS-induced symptoms could be reduced by pre-treatment with bupropion, a norepinephrine and dopamine reuptake inhibitor. In this double-blind, randomized, placebo-controlled, cross-over study, 10 healthy subjects received intravenous LPS (0.8 ng/kg) after oral pre-treatment with bupropion (75 mg twice a day) or placebo for 7 days. The Montgomery-Ĺsberg Depression Rating Scale (MADRS), the Profile of Mood States (POMS), and a visual analog scale (VAS) were used to measure depressive symptoms. Serum levels of inflammatory cytokines and chemokines were measured with electrochemiluminescence assays. The results of this study, which must be considered preliminary, showed that LPS administration was associated with (1) increase in serum levels of all cytokines and chemokines assayed; (2) increase in total MADRS score, mostly due to items 7 (lassitude) and 8 (anhedonia); (3) increase in fatigue; (4) decrease in vigor; and (5) decrease in social interest. Bupropion pre-treatment had no statistically significant effect on the innate immune response to LPS or on LPS-induced behavioral changes, suggesting that 1-week pre-treatment with bupropion does not inhibit LPS-induced fatigue and anhedonia, contrary to what was found previously with citalopram. PMID:23064079

DellaGioia, Nicole; Devine, Lesley; Pittman, Brian; Hannestad, Jonas

2013-07-01

183

Effect of Indigofera tinctoria Linn on liver antioxidant defense system during D-galactosamine/endotoxin-induced acute hepatitis in rodents.  

PubMed

Effects of pre-treatment with the alcoholic extract of I. tinctoria (500 mg/kg body wt/day, p.o. for 21 days) on liver antioxidant defense system during acute hepatitis induced by D-galactosamine (D-GalN)/endotoxin (LPS extracted by phenol water method from E. coli serotype 0111.B4; 300 mg and 30 micrograms/kg body wt/day, i.p., 18 hr before the assay) were investigated on the activities of enzymic antioxidants such as superoxide dismutase, catalase, glutathione peroxidase and glutathione-s-transferase, and levels of total reduced glutathione in the liver of normal and experimental groups of male albino rats. Since lipid peroxidation and associated membrane damage is a key feature of D-galN/LPS-induced liver injury, the levels of lipid peroxides, was estimated and used as an index of oxidative stress. D-GalN/endotoxin-induced hepatic damage was manifested by a significant decrease in the activities of antioxidant enzymes, decreased glutathione levels and increased levels of lipid peroxides. I. tinctoria pre-treated rats showed considerable protection against D-galN/endotoxin, induced oxidative stress as evidenced by a significant increase in the activities of all the antioxidant enzymes studied and significant decrease in the levels of lipid peroxides. Results indicate that pretreatment with I. tinctoria extract in rats is very effective in reducing D-GalN/endotoxin-induced oxidative stress suggesting an antioxidant effect. PMID:11480218

Sreepriya, M; Devaki, T; Balakrishna, K; Apparanantham, T

2001-02-01

184

Hepatic uptake and deacylation of the lipopolysaccharide in bloodborne lipopolysaccharide-lipoprotein complexes  

PubMed Central

Much evidence indicates that bacterial lipopolysaccharide (LPS, endotoxin) is removed from the bloodstream mainly by the liver, yet the hepatic uptake mechanisms remain uncertain and controversial. In plasma, LPS can be either “free” (as aggregates, bacterial membrane fragments, or loosely bound to albumin, CD14, or other proteins) or “bound” (complexed with lipoproteins). Whereas most free LPS is taken up by Kupffer cells, lipoprotein-bound LPS has seemed to be cleared principally by hepatocytes. Here we compared the liver’s ability to take up and deacylate free LPS aggregates and the LPS in preformed LPS-HDL (high density lipoprotein) complexes. In mice examined from 1 hour to 7 days after a small amount of fluorescent (FITC-)LPS was injected into a lateral tail vein, we found FITC-LPS almost entirely within, or adjacent to, Kupffer cells. As expected, FITC-LPS complexed with HDL (FITC-LPS-HDL) disappeared more slowly from the circulation and a smaller fraction of the injected dose of FITC-LPS was found in the liver. Unexpectedly, the FITC-LPS injected as FITC-LPS-HDL complexes was also found within sinusoids, adjacent to or within Kupffer cells. In other experiments, we found that both free and HDL-bound radiolabeled LPS underwent enzymatic deacylation by acyloxyacyl hydrolase (AOAH), the LPS-inactivating enzyme that is principally produced within the liver by Kupffer cells. Our observations suggest that Kupffer cells and AOAH play important roles in clearing and catabolizing both free LPS and the LPS in circulating LPS-HDL complexes. PMID:22441700

Shao, Baomei; Munford, Robert; Kitchens, Richard L.; Varley, Alan W.

2014-01-01

185

Oil composition of high-fat diet affects metabolic inflammation differently in connection with endotoxin receptors in mice.  

PubMed

Low-grade inflammation observed in obesity is a risk factor for cardiovascular disease. Recent studies revealed that this would be linked to gut-derived endotoxemia during fat digestion in high-fat diets, but nothing is known about the effect of lipid composition. The study was designed to test the impact of oil composition of high-fat diets on endotoxin metabolism and inflammation in mice. C57/Bl6 mice were fed for 8 wk with chow or isocaloric isolipidic diets enriched with oils differing in fatty acid composition: milk fat, palm oil, rapeseed oil, or sunflower oil. In vitro, adipocytes (3T3-L1) were stimulated or not with lipopolysaccharide (LPS; endotoxin) and incubated with different fatty acids. In mice, the palm group presented the highest level of IL-6 in plasma (P < 0.01) together with the highest expression in adipose tissue of IL-1? and of LPS-sensing TLR4 and CD14 (P < 0.05). The higher inflammation in the palm group was correlated with a greater ratio of LPS-binding protein (LBP)/sCD14 in plasma (P < 0.05). The rapeseed group resulted in higher sCD14 than the palm group, which was associated with lower inflammation in both plasma and adipose tissue despite higher plasma endotoxemia. Taken together, our results reveal that the palm oil-based diet resulted in the most active transport of LPS toward tissues via high LBP and low sCD14 and the greatest inflammatory outcomes. In contrast, a rapeseed oil-based diet seemed to result in an endotoxin metabolism driven toward less inflammatory pathways. This shows that dietary fat composition can contribute to modulate the onset of low-grade inflammation through the quality of endotoxin receptors. PMID:22094473

Laugerette, Fabienne; Furet, Jean-Pierre; Debard, Cyrille; Daira, Patricia; Loizon, Emmanuelle; Géloën, Alain; Soulage, Christophe O; Simonet, Claire; Lefils-Lacourtablaise, Jennifer; Bernoud-Hubac, Nathalie; Bodennec, Jacques; Peretti, Noël; Vidal, Hubert; Michalski, Marie-Caroline

2012-02-01

186

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

PubMed

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

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

2014-10-01

187

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

PubMed Central

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

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

2014-01-01

188

Lack of the Receptor for Advanced Glycation End-Products Attenuates E. coli Pneumonia in Mice  

E-print Network

Lack of the Receptor for Advanced Glycation End- Products Attenuates E. coli Pneumonia in Mice were used to determine the role of RAGE signaling in lipopolysaccharide (LPS) and E. coli induced acute of mouse soluble RAGE on E. coli injury was also investigated. Methodology/Principal Findings: C57BL/6 wild

Schierup, Mikkel Heide

189

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

USGS Publications Warehouse

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

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

2002-01-01

190

Modulation of lipopolysaccharide-induced oxidative stress by capsaicin.  

PubMed

This study investigated the effect of capsaicin (the active principle of hot red pepper and a sensory excitotoxin) on oxidative stress after systemic administration of the endotoxin lipopolysaccharide (100 ?g/kg, i.p.) in rats. Capsaicin (15, 150 or 1,500 ?g/kg; 10, 100 or 400 ?g/mL) was given via intragastric (i.g.) or intraperitoneal (i.p.) routes at time of endotoxin administration. Rats were killed 4 h later. Malondialdehyde (MDA) and reduced glutathione (GSH) were measured in brain, liver, and lungs. Alanine aminotransferase (ALT), aspartate aminotransferase, alkaline phosphatase (ALP), nitric oxide, and glucose were measured in serum. In addition, histopathological examination of liver tissue was performed. In LPS-treated rats, hepatic GSH increased significantly by 40.8% after i.p. capsaicin at 1,500 ?g/kg. Liver MDA increased significantly by 32.9% after the administration of i.g. capsaicin at 1,500 ?g/kg and by 27.8 and 37.6% after the administration of i.p. capsaicin at 150 and 1,500 ?g/kg, respectively. In lung tissue, both MDA and GSH were decreased by capsaicin administration. MDA decreased by 19-20.8% after i.g. capsaicin and by 17.5-23.2% after i.p. capsaicin (150-1,500 ?g/kg), respectively. GSH decreased by 39.3-64.3% and by 35.7-41.1% after i.g. or i.p. capsaicin (150-1,500 ?g/kg), respectively. Brain GSH increased significantly after the highest dose of i.g. or i.p. capsaicin (by 20.6 and 15.9%, respectively). The increase in serum ALT and ALP after endotoxin administration was decreased by oral or i.p. capsaicin. Serum nitric oxide showed marked increase after LPS injection, but was markedly decreased after capsaicin (1,500 ?g/kg, i.p.). Serum glucose increased markedly after the administration of LPS, and was normalized by capsaicin treatment. It is suggested that in the presence of mild systemic inflammation, acute capsaicin administration might alter oxidative status in some tissues and exert an anti-inflammatory effect. Capsaicin exerted protective effects in the liver and lung against the LPS-induced tissue damage. PMID:22127606

Abdel-Salam, Omar M E; Abdel-Rahman, Rehab Fawzy; Sleem, Amany A; Farrag, Abdel Razik

2012-08-01

191

In Vitro Attachment of Radioactive Endotoxins to Lysosomes  

PubMed Central

The experiments reported here demonstrate that under certain conditions endotoxin can interact with lysosomes in vitro. After incubation of large granular fraction with 51Cr-labeled antigen under the conditions required for acid hydrolytic activity, radioactivity was associated with the pellet after centrifugation. This effect can be inhibited by preincubation of the large granular fraction with unlabeled homologous or heterologous endotoxins. High resolution autoradiography showed that 14C-labeled endotoxin was predominantly attached to the lysosomes contained in the large granular fraction. The mechanism of this interaction and its relationship to the toxic effect of endotoxins on lysosomes are discussed. Images PMID:4949505

Bona, C.; Chedid, L.; Lamensans, A.

1971-01-01

192

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. PMID:23497755

2013-01-01

193

Blockade of nitric oxide formation in the rat brain does not disturb development of endotoxin tolerance.  

PubMed

The involvement of nitric oxide (NO) in tolerance development to endotoxin has been proposed because peripherally administered NG-nitro-L-arginine methyl ester (L-NAME) (NO synthases inhibitor) delays the endotoxin tolerance formation. Since L-NAME is capable of crossing the blood-brain barrier, the question arises of where activity of NO synthases (inside or outside the blood-brain barrier) is crucial for development of endotoxin tolerance. To clarify the role of different NO synthases (NOS) isoforms, acting in the brain, on the tolerance development, effects of highly selective iNOS and nNOS inhibitors on stepwise attenuation of febrile response during tolerance formation were examined in freely moving biotelemetered rats. We monitored changes in febrile response during the development of tolerance to repeated intraperitoneal (i.p.) injections of lipopolysaccharide (LPS) (50 ?g/kg) along with intracerebroventricular (i.c.v.) injections of vinyl-L-NIO, a neuronal NOS inhibitor, or aminoguanidine, an inducible NOS inhibitor at a dose of 10 ?g/rat. Both inhibitors injected at the selected doses had no effect on normal day-time as well as night-time body temperature. Rats were treated with LPS and NOS inhibitors for three consecutive days. On the fourth day, all rats were injected with LPS alone. Rats repeatedly injected with LPS became tolerant to pyrogenic effect of LPS as early as on the second day of the experiment. The treatment with iNOS or nNOS inhibitors completely suppressed fever due to the first, second and third LPS injection. When rats, which received the three i.c.v. injections of vL-NIO along with i.p. injections of LPS, were then treated the fourth time with LPS alone, they responded with virtually identical changes in body temperature to that of the group of rats that were injected with water i.c.v. and LPS i.p. for three consecutive days. This data indicate that both group of rats became tolerant to pyrogenic effect of LPS. It is, therefore, reasonable to hypothesize that activation of nNOS and iNOS inside the brain is not important for the development of endotoxin tolerance. PMID:24388893

Soszynski, D; Daniluk, M; Galazka, M; Dmitruk, K

2013-12-01

194

Bacterial lipopolysaccharides and innate immunity  

Microsoft Academic Search

Bacterial lipopolysaccharides (LPS) are the major outer surface membrane components present in almost all Gram-negative bacteria and act as extremely strong stimulators of innate or natural immunity in diverse eukaryotic species ranging from insects to humans. LPS consist of a poly- or oligosaccharide region that is anchored in the outer bacterial membrane by a specific carbohydrate lipid moiety termed lipid

Christian Alexander; E. T. Rietschel

2001-01-01

195

Metropolitan home living conditions associated with indoor endotoxin levels  

Microsoft Academic Search

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

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

2001-01-01

196

Bacterial lipopolysaccharide (LPS)-induced type 2 iodothyronine deiodinase (D2) activation in the mediobasal hypothalamus (MBH) is independent of the LPS-induced fall in serum thyroid hormone levels  

Microsoft Academic Search

By administration of bacterial lipopolysaccharide (LPS) to intact and T4-replaced thyroidectomized rats, we demonstrate that in contrast to the cortex and anterior pituitary, there is a persistent increase in type 2 iodothyronine deiodinase (D2) activity in the mediobasal hypothalamus (MBH). We propose that endotoxin-induced D2 activation in the MBH is independent of circulating levels of thyroid hormone and that this

Csaba Fekete; Sumit Sarkar; Marcelo A. Christoffolete; Charles H. Emerson; Antonio C. Bianco; Ronald M. Lechan

2005-01-01

197

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

R. R. SCHUMANN; C. J. KIRSCHNING; A. UNBEHAUN; H. ABERLE; H.-P. KNOPF; N. LAMPING; R. J. ULEVITCH; Max Delbruck; Max Planck

1996-01-01

198

Visualization and analysis of lipopolysaccharide distribution in binary phospholipid bilayers  

SciTech Connect

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

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

2009-05-22

199

The relationship between the vascular manifestations of shock produced by endotoxin, trauma, and hemorrhage. II. The possible role of the reticulo-endothelial system in resistance to each type of shock.  

PubMed

In studies designed to establish the interrelationship between bacterial endotoxins and the vascular sequelae of hemorrhagic and traumatic shock, the effect of factors known to influence the phagocytic behavior of the reticulo-endothelial system (RES) were investigated. Measures which induced a so called "blockade" of the RES were uniformly associated with an exacerbation of the vascular effects of the endotoxin of E. coli. Such pretreatment also counteracted the cross-tolerance induced by endotoxins against the lethal effects of hemorrhage or drum trauma. The vascular reactions characteristic of irreversible hemorrhagic shock could be simulated by a combination of pretreatment with carbon or proferrin and the infusion of small doses of E. coli endotoxin. An increase in the phagocytic activity of the RES, induced by repeated injections of certain colloids, was associated with an enhanced tolerance of shock. Measurement of carbon clearance values indicated that although an augmented phagocytic capacity was present in rats with induced tolerance to bacterial endotoxins, the development of resistance to trauma was not associated with a comparable change in the phagocytic function of the RES. PMID:13463250

ZWEIFACH, B W; BENACERRAF, B; THOMAS, L

1957-09-01

200

Endotoxin Exposure Is a Risk Factor for Asthma  

PubMed Central

Background: Although research has shown that early life exposure to household endotoxin protects against development of allergies, studies are less clear on the relationship between household endotoxin exposure and prevalence of wheezing and asthma. We as- sayed 2,552 house dust samples in a representative nationwide sam- ple to explore relationships between endotoxin exposures and risk factors for asthma, asthma symptoms, and medication use. Methods: House dust was vacuum-sampled from five locations within homes and assayed for endotoxin. Health, demographic, and housing information was assessed through questionnaire and on-site evaluation of 2,456 residents of 831 homes selected to represent the demographics of the United States. Results: Endotoxin concentration (EU/mg) and load (EU/m2) were highly correlated (r = 0.73–0.79). Geometric mean endotoxin concentrations were as follows (in EU/mg): bedroom floors, 35.3 (5th–95th percentile, 5.0–260); bedding, 18.7 (2.0–142); family room floors, 63.9 (11.5–331); sofas, 44.8 (6.4–240); and kitchen floors, 80.5 (9.8–512). Multivariate analysis demonstrated significant relationships between increasing endotoxin levels and diagnosed asthma, asthma symptoms in the past year, current use of asthma medications, and wheezing among residents of the homes. These relationships were strongest for bedroom floor and bedding dust and were observed in adults only. Modeling the joint effect of bedding and bedroom floor endotoxin on recent asthma symptoms yielded an adjusted odds ratio of 2.83 (95% confidence interval, 1.01–7.87). When stratified by allergy status, allergic subjects with higher endotoxin exposure were no more likely to have diagnosed asthma or asthma symptoms than nonallergic subjects. Conclusion: This study demonstrates that household endotoxin exposure is a significant risk factor for increased asthma prevalence. PMID:16141442

Thorne, Peter S.; Kulhánková, Katarina; Yin, Ming; Cohn, Richard; Arbes, Samuel J.; Zeldin, Darryl C.

2005-01-01

201

BIOLOGICAL PROPERTIES OF PARENT ENDOTOXINS AND LIPOID FRACTIONS, WITH A KINETIC STUDY OF ACID-HYDROLYZED ENDOTOXIN  

PubMed Central

The biological potencies of a number of lipid fractions separated from endotoxins by acid hydrolysis, including the material known as lipid A, were determined in parallel with those of their parent endotoxins, employing bio-assays based on the following dose-related host responses: fever, resistance to infection, tumor damage, primary inflammation of skin, and lethality. Without exception, lipid fractions dispersed by detergents exerted less than 1 per cent of the biological activity of the potent endotoxins from which they were derived. A study was made of the rate at which biologic activities diminished in relation to the release of bound lipid during progressive hydrolysis of Salmonella enteritidis endotoxin with dilute acid. Each of the five assays for endotoxin revealed that biological activity had been reduced to negligible proportions prior to any significant liberation from the endotoxin of water-insoluble firmly bound lipid. The major pharmacological activity of endotoxins, therefore, is acid-labile and cannot be accounted for in isolated lipids. This conclusion is also supported by the finding that lipids with activity similar to that of lipid A could be obtained by non-hydrolytic methods without diminishing the potency of the parent endotoxins. PMID:13905235

Haskins, Willard T.; Landy, Maurice; Milner, Kelsey C.; Ribi, Edgar

1961-01-01

202

Studies with Radioactive Endotoxin III. Localization of 3H-Labelled Endotoxin in the Formed Elements of the Blood and Detection of Endotoxin in Calf Blood with the Limulus Amebocyte Lysate  

PubMed Central

3H-labelled Pseudomonas endotoxin was incubated in vitro with blood from nontolerant and endotoxin tolerant calves. Formed elements were separated from serial samples of the incubated mixtures. The labelled endotoxin became associated with neutrophils, monocytes, lymphocytes, platelets and erythrocytes. Association of 3H-endotoxin with formed elements of the blood occurred during the first five minutes of incubation and did not significantly change over the course of a three hour incubation period. Tolerance did not result in increased uptake of 3H-endotoxin by formed elements of the blood. Tolerance of calves to endotoxin is apparently not due to increased uptake of endotoxin by formed elements of the blood. The Limulus amebocyte lysate assay was unreliable for the detection of endotoxin which was present in calf blood in vitro and requires further modification. ImagesFig. 2.Fig. 3.Fig. 4.Fig. 5. PMID:4279756

Maxie, M. G.; Valli, V. E. O.

1974-01-01

203

Nutritional regulation of plasma tumor necrosis factor-alpha and plasma and urinary nitrite/nitrate responses to endotoxin in cattle.  

PubMed

Effects of dietary protein level with and without L-arginine (Arg) infusion on plasma tumor necrosis factor-alpha (TNF-alpha) response to endotoxin (lipopolysaccharide [LPS]) as well as plasma concentration and urine output of nitrite and nitrate (NOx), the stable end products of nitric oxide radical (NO), were studied in beef heifers (275-310 kg body wt). The animals were fed low- (LP; 7.96%) or high- (HP; 13.94%) protein diets for 10 days before LPS administration (Escherichia coli; 0.2 microgram/kg, iv). L-Arginine in saline (0.5 g/kg body wt) or saline was infused for 8 hr with one-third of total Arg infused before LPS administration. Plasma TNF-alpha concentrations increased in all heifers after LPS injection (peak at 1 hr and return to baseline at 4 hr); however, concentrations were lower in HP- than in LP-fed heifers at 1, 2, and 3 hr. Infusion of Arg did not affect plasma TNF-alpha response to LPS. Plasma NOx concentrations increased in all heifers after LPS challenge; compared with saline, Arg infusion increased the total response (integrated area under concentration curve) in LP- but not in HP-fed heifers. Relative to pretreatment period, the rate of NOx output in urine collected 2-6 hr after LPS administration increased in all heifers regardless of dietary protein level and was further amplified by Arg infusion. The rate of NOx output in urine collected 6-24 hr after LPS challenge was even higher in LP-fed heifers infused with Arg but returned to the basal values in other groups. Activity of hepatic inducible NO synthase was not affected by LPS, Arg, or dietary protein level at the time points studied. The data suggest that dietary protein levels can modulate both TNF-alpha and NO responses to LPS in cattle; high dietary protein intake decreases TNF-alpha response and attenuates the conversion of supplemental Arg to NO. PMID:9270720

Kahl, S; Elsasser, T H; Blum, J W

1997-09-01

204

Some Metabolic Aspects of Tolerance to Bacterial Endotoxin1  

PubMed Central

Berry, L. Joe (Bryn Mawr College, Bryn Mawr, Pa.), and Dorothy S. Smythe. Some metabolic aspects of tolerance to bacterial endotoxin. J. Bacteriol. 90:970–977. 1965.—The tolerance to bacterial endotoxins which is produced in mice given a series of daily injections of heat-killed Salmonella typhimurium failed to occur when actinomycin D was administered with the heat-killed cells. Neither ethionine nor 2-thiouracil, when given with endotoxin, altered the development of tolerance. An injection of endotoxin, actinomycin D, or ethionine lowered the activity of the liver enzyme tryptophan pyrrolase more significantly at either 4 or 17 hr postinjection in normal mice than in tolerant mice. Similarly, an injection of either saccharated iron oxide or Thorotrast lowered liver tryptophan pyrrolase activity more extensively in normal than in tolerant animals. Activation of the reticuloendothelial system (RES) of tolerant mice, as determined by an accelerated rate of carbon clearance from the blood, was observed, but this was prevented by the appropriate dose of actinomycin D. Similar results were obtained when saccharated iron oxide, rather than endotoxin, was used to activate the RES, but these animals were not resistant to endotoxin and their tryptophan pyrrolase was normally diminished after an injection of endotoxin. Thus, RES activation may occur without tolerance developing. A more nearly normal level of enzyme activity appears to be characteristic of the tolerant state. PMID:4158706

Berry, L. Joe; Smythe, Dorothy S.

1965-01-01

205

The immunobiology of toll-like receptor 4 agonists: from endotoxin tolerance to immunoadjuvants.  

PubMed

Lipopolysaccharide (LPS, endotoxin) is a structural component of the gram-negative outer membrane. The lipid A moiety of LPS binds to the LPS receptor complex expressed by leukocytes, endothelial cells, and parenchymal cells and is the primary component of gram-negative bacteria that is recognized by the immune system. Activation of the LPS receptor complex by native lipid A induces robust cytokine production, leukocyte activation, and inflammation, which is beneficial for clearing bacterial infections at the local level but can cause severe systemic inflammation and shock at higher challenge doses. Interestingly, prior exposure to LPS renders the host resistant to shock caused by subsequent LPS challenge, a phenomenon known as endotoxin tolerance. Treatment with lipid A has also been shown to augment the host response to infection and to serve as a potent vaccine adjuvant. However, the adverse effects associated with the pronounced inflammatory response limit the use of native lipid A as a clinical immunomodulator. More recently, analogs of lipid A have been developed that possess attenuated proinflammatory activity but retain attractive immunomodulatory properties. The lipid A analog monophosphoryl lipid A exhibits approximately 1/1,000th of the toxicity of native lipid A but retains potent immunoadjuvant activity. As such, monophosphoryl lipid A is currently used as an adjuvant in several human vaccine preparations. Because of the potency of lipid A analogs as immunoadjuvants, numerous laboratories are actively working to identify and develop new lipid A mimetics and to optimize their efficacy and safety. Based on those characteristics, lipid A analogs represent an attractive family of immunomodulators. PMID:23989337

Bohannon, Julia K; Hernandez, Antonio; Enkhbaatar, Perenlei; Adams, William L; Sherwood, Edward R

2013-12-01

206

The Immunobiology of TLR4 Agonists: From Endotoxin Tolerance to Immunoadjuvants  

PubMed Central

Lipopolysaccharide (LPS, endotoxin) is a structural component of the Gram negative outer membrane. The lipid A moiety of LPS binds to the LPS receptor complex expressed by leukocytes, endothelial cells and parenchymal cells and is the primary component of Gram negative bacteria that is recognized by the immune system. Activation of the LPS receptor complex by native lipid A induces robust cytokine production, leukocyte activation and inflammation, which is beneficial for clearing bacterial infections at the local level but can cause severe systemic inflammation and shock at higher challenge doses. Interestingly, prior exposure to LPS renders the host resistant to shock caused by subsequent LPS challenge, a phenomenon known as endotoxin tolerance. Treatment with lipid A has also been shown to augment the host response to infection and to serve as a potent vaccine adjuvant. However, the side effects associated with the pronounced inflammatory response limits the use of native lipid A as a clinical immunomodulator. More recently, analogs of lipid A have been developed that possess attenuated pro-inflammatory activity but retain attractive immunomodulatory properties. The lipid A analog monophosphoryl lipid A (MPLA) exhibits approximately 1/1000th of the toxicity of native lipid A but retains potent immunoadjuvant activity. As such, MPLA is currently employed as an adjuvant in several human vaccine preparations. Due to the potency of lipid A analogs as immunoadjuvants, numerous laboratories are actively working to identify and develop new lipid A mimetics and to optimize their efficacy and safety. Based on those characteristics, lipid A analogs represent an attractive family of immunomodulators. PMID:23989337

Bohannon, Julia K.; Hernandez, Antonio; Enkhbaatar, Perenlei; Adams, William L.; Sherwood, Edward R.

2014-01-01

207

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

PubMed Central

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

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

2013-01-01

208

INTERACTIONS OF THE COMPLEMENT SYSTEM WITH THE SURFACE AND ENDOTOXIC LIPOPOLYSACCHARIDE OF VEILLONELLA ALCALESCENS  

PubMed Central

Electron microscopic studies demonstrated that lesions were produced on the endotoxic lipopolysaccharide (LPS) as well as on the cell surface of V. alcalescens after reaction with fresh guinea pig serum. These lesions were approximately 90 A in diameter, and were seen on two characteristic structural entities derived from LPS preparations after incubation with serum. The use of numerous inhibitors, inactivators, and reaction conditions affecting hemolytic C' activity revealed that these lesions were mediated by the C' system. Concomitant with lesion formation, C' was fixed; the effect on classical C'3 activity was pronounced. It is concluded that endotoxic LPS, as contained in the outer three-layered membrane of the bacterial cell, is a substrate for the C' enzymes. It is suggested that certain biological activities of endotoxin may derive from its effects on the C' system. PMID:4164691

Bladen, Howard A.; Gewurz, Henry; Mergenhagen, Stephan E.

1967-01-01

209

Eicosapentaenoic acid preserves diaphragm force generation following endotoxin administration  

PubMed Central

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

2010-01-01

210

The transhepatic endotoxin gradient is present despite liver cirrhosis and is attenuated after transjugular portosystemic shunt (TIPS).  

PubMed Central

Background Translocation of gut-derived bacterial products such as endotoxin is a major problem in liver cirrhosis. Methods To assess the hepatic clearance of bacterial products in individuals with cirrhosis, we tested concentrations of Gram-negative bacterial lipopolysaccharide (LPS), LPS-binding protein (LBP), and the precursor of nitric oxide (NO), L-arginine, in a cohort of 8 stable patients with liver cirrhosis before and after elective transjugular portosystemic shunt (TIPS) implantation, including central venous, hepatic venous, and portal venous measurements. Results Using an adapted LPS assay, we detected high portal venous LPS concentrations (mean 1743 ± 819 pg/mL). High concentrations of LPS were detectable in the central venous blood (931 ± 551 pg/mL), as expected in persons with cirrhosis. The transhepatic LPS gradient was found to be 438 ± 287 pg/mL, and 25 ± 12% of portal LPS was cleared by the cirrhotic liver. After TIPS, central venous LPS concentrations increased in the hepatic and central veins, indicating shunting of LPS with the portal blood through the stent. This paralleled a systemic increase of L-arginine, whereas the NO synthase inhibitor asymmetric dimethylarginine (ADMA) remained unchanged, suggesting that bacterial translocation may contribute to the pathogenesis of circulatory dysfunction post-TIPS. Conclusions This study provides quantitative estimates of the role of the liver in the pathophysiology of bacterial translocation. The data indicate that the cirrhotic liver retains the capacity for clearance of bacterial endotoxin from the portal venous blood and that TIPS implantation attenuates this clearance. Thus, increased endotoxin concentrations in the systemic circulation provide a possible link to the increased encephalopathy in TIPS patients. PMID:21978390

2011-01-01

211

Aspirin-triggered resolvin D1 down-regulates inflammatory responses and protects against endotoxin-induced acute kidney injury.  

PubMed

The presence of endotoxin in blood can lead to acute kidney injury (AKI) and septic shock. Resolvins, the endogenous lipid mediators derived from docosahexaenoic acid, have been reported to exhibit potent anti-inflammatory action. Using a mouse model of lipopolysaccharide (LPS)-induced AKI, we investigated the effects of aspirin-triggered resolvin D1 (AT-RvD1) on inflammatory kidney injury. Administration of AT-RvD1 1h after LPS challenge protected the mice from kidney injury as indicated by the measurements of blood urea nitrogen, serum creatinine, and morphological alterations associated with tubular damage. The protective effects were evidenced by decreased neutrophil infiltration in the kidney indicating reduction in inflammation. AT-RvD1 treatment restored kidney cell junction protein claudin-4 expression, which was otherwise reduced after LPS challenge. AT-RvD1 treatment inhibited endotoxin-induced NF-?B activation and suppressed LPS-induced ICAM-1 and VCAM-1 expression in the kidney. Moreover, AT-RvD1 treatment markedly decreased LPS-induced IL-6 level in the kidney and blocked IL-6-mediated signaling including STAT3 and ERK phosphorylation. Our findings demonstrate that AT-RvD1 is a potent anti-inflammatory mediator in LPS-induced kidney injury, and AT-RvD1 has therapeutic potential against AKI during endotoxemia. PMID:24709673

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

2014-06-01

212

Lipopolysaccharide Inhibits the Channel Activity of the P2X7 Receptor  

PubMed Central

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

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

2011-01-01

213

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

PubMed Central

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

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

2014-01-01

214

40 CFR 180.1108 - Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated into killed Pseudomonas...  

Code of Federal Regulations, 2011 CFR

...false Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated...1108 Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated... The delta endotoxin of Bacillus thuringiensis variety San Diego...

2011-07-01

215

40 CFR 180.1108 - Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated into killed Pseudomonas...  

Code of Federal Regulations, 2013 CFR

...false Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated...1108 Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated... The delta endotoxin of Bacillus thuringiensis variety San Diego...

2013-07-01

216

40 CFR 180.1108 - Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated into killed Pseudomonas...  

...false Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated...1108 Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated... The delta endotoxin of Bacillus thuringiensis variety San Diego...

2014-07-01

217

40 CFR 180.1108 - Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated into killed Pseudomonas...  

Code of Federal Regulations, 2012 CFR

...false Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated...1108 Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated... The delta endotoxin of Bacillus thuringiensis variety San Diego...

2012-07-01

218

40 CFR 180.1108 - Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated into killed Pseudomonas...  

Code of Federal Regulations, 2010 CFR

...false Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated...1108 Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated... The delta endotoxin of Bacillus thuringiensis variety San Diego...

2010-07-01

219

A Critical Role for Human Caspase-4 in Endotoxin Sensitivity  

PubMed Central

Response to endotoxins is an important part of the organismal reaction to Gram-negative bacteria and plays a critical role in sepsis and septic shock, as well as other conditions such as metabolic endotoxemia. Humans are generally more sensitive to endotoxins when compared with experimental animals such as mice. Inflammatory caspases mediate endotoxin-induced IL-1? secretion and lethality in mice, and caspase-4 is an inflammatory caspase that is found in the human, and not mouse, genome. To test whether caspase-4 is involved in endotoxin sensitivity, we developed a transgenic mouse expressing human caspase-4 in its genomic context. Caspase-4 transgenic mice exhibited significantly higher endotoxin sensitivity, as measured by enhanced cytokine secretion and lethality following LPS challenge. Using bone marrow–derived macrophages, we then observed that caspase-4 can support activation of caspase-1 and secretion of IL-1? and IL-18 in response to priming signals (LPS or Pam3CSK4) alone, without the need for second signals to stimulate the assembly of the inflammasome. These findings indicate that the regulation of caspase-1 activity by human caspase-4 could represent a unique mechanism in humans, as compared with laboratory rodents, and may partially explain the higher sensitivity to endotoxins observed in humans. Regulation of the expression, activation, or activity of caspase-4 therefore represents targets for systemic inflammatory response syndrome, sepsis, septic shock, and related disorders. PMID:24879791

Kajiwara, Yuji; Schiff, Tamar; Voloudakis, Georgios; Gama Sosa, Miguel A.; Elder, Gregory; Bozdagi, Ozlem

2014-01-01

220

Coarse particulate matter and airborne endotoxin within wood stove homes.  

PubMed

Emissions from indoor biomass burning are a major public health concern in developing areas of the world. Less is known about indoor air quality, particularly airborne endotoxin, in homes burning biomass fuel in residential wood stoves in higher income countries. A filter-based sampler was used to evaluate wintertime indoor coarse particulate matter (PM????.?) and airborne endotoxin (EU/mł, EU/mg) concentrations in 50 homes using wood stoves as their primary source of heat in western Montana. We investigated number of residents, number of pets, dampness (humidity), and frequency of wood stove usage as potential predictors of indoor airborne endotoxin concentrations. Two 48-h sampling events per home revealed a mean winter PM????.? concentration (± s.d.) of 12.9 (± 8.6) ?g/mł, while PM?.? concentrations averaged 32.3 (± 32.6) ?g/mł. Endotoxin concentrations measured from PM????.? filter samples were 9.2 (± 12.4) EU/mł and 1010 (± 1524) EU/mg. PM????.? and PM?.? were significantly correlated in wood stove homes (r = 0.36, P < 0.05). The presence of pets in the homes was associated with PM????.? but not with endotoxin concentrations. Importantly, none of the other measured home characteristics was a strong predictor of airborne endotoxin, including frequency of residential wood stove usage. PMID:23551341

McNamara, M; Thornburg, J; Semmens, E; Ward, T; Noonan, C

2013-12-01

221

PHYSICOCHEMICAL CHANGES IN ENDOTOXIN ASSOCIATED WITH LOSS OF BIOLOGICAL POTENCY  

PubMed Central

Ribi, Edgar (National Institute of Allergy and Infectious Diseases, Rocky Mountain Laboratory, Hamilton, Mont.), Willard T. Haskins, Kelsey C. Milner, Robert L. Anacker, Daniel B. Ritter, Granville Goode, Robert-John Trapani, and Maurice Landy. Physicochemical changes in endotoxin associated with loss of biological potency. J. Bacteriol. 84:803–814. 1962.—The preparation of endotoxins whose gross chemical composition approached that of refined polysaccharide haptenes raised anew the question of which features of composition and structure are essential for their characteristic host reactivity. Alterations in the physicochemical, immunochemical, and biological properties of Salmonella enteritidis endotoxin subjected to hydrolysis with 0.1 n acetic acid were therefore investigated to relate physical characteristics to biological attributes. As hydrolysis proceeded, the decline in biological potency was paralleled by dissociation of endotoxin into particles of the size of haptenic polysaccharide. The potency still present at various stages of hydrolysis could be accounted for by residual undissociated endotoxin. These findings are consistent with the hypothesis that a macromolecular complex of critical size is one of the major requirements for endotoxin to elicit its characteristic effects in the mammalian host. Images PMID:13982018

Ribi, Edgar; Haskins, Willard T.; Milner, Kelsey C.; Anacker, Robert L.; Ritter, Daniel B.; Goode, Granville; Trapani, Robert-John; Landy, Maurice

1962-01-01

222

Cow allergen (Bos d2) and endotoxin concentrations are higher in the settled dust of homes proximate to industrial-scale dairy operations.  

PubMed

Airborne contaminants produced by industrial agricultural facilities contain chemical and biological compounds that can impact the health of residents living in close proximity. Settled dust can be a reservoir for these contaminants and can influence long-term exposures. In this study, we sampled the indoor- and outdoor-settled dust from 40 homes that varied in proximity to industrial-scale dairies (ISD; industrial-scale dairy, a term used in this paper to describe a large dairy farm and adjacent waste sprayfields, concentrated animal feeding operation or animal feeding operation, that uses industrial processes) in the Yakima Valley, Washington. We analyzed settled dust samples for cow allergen (Bos d2, a cow allergen associated with dander, hair, sweat and urine, it is a member of the lipocalin family of allergens associated with mammals), mouse allergen (Mus m1; major mouse allergen, a mouse urinary allergen, in the lipocalin family), dust mite allergens (Der p1 (Dermatophagoides pteronissinus 1) and Der f1 (Dermatophagoides farinae 1)), and endotoxin (a component of the cell walls of gram negative bacteria, lipopolysaccharide, which can be found in air and dust and can produce a strong inflammatory response). A concentration gradient was observed for Bos d2 and endotoxin measured in outdoor-settled dust samples based on proximity to ISD. Indoor-settled dust concentrations of Bos d2 and endotoxin were also highest in proximal homes. While the associated health effects of exposure to cow allergen in settled dust is unknown, endotoxin at concentrations observed in these proximal homes (100?EU/mg) has been associated with increased negative respiratory health effects. These findings document that biological contaminants emitted from ISDs are elevated in indoor- and outdoor-settled dust samples at homes close to these facilities and extend to as much as three miles (4.8?km) away.Journal of Exposure Science and Environmental Epidemiology advance online publication, 20 August 2014; doi:10.1038/jes.2014.57. PMID:25138294

Williams, D' Ann L; McCormack, Meredith C; Matsui, Elizabeth C; Diette, Gregory B; McKenzie, Shawn E; Geyh, Alison S; Breysse, Patrick N

2014-08-20

223

An Anti-Interleukin-2 Receptor Drug Attenuates T- Helper 1 Lymphocytes-Mediated Inflammation in an Acute Model of Endotoxin-Induced Uveitis  

PubMed Central

The aim of the present study was to evaluate the anti-inflammatory efficacy of Daclizumab, an anti-interleukin-2 receptor drug, in an experimental uveitis model upon a subcutaneous injection of lipopolysaccharide into Lewis rats, a valuable model for ocular acute inflammatory processes. The integrity of the blood-aqueous barrier was assessed 24 h after endotoxin-induced uveitis by evaluating two parameters: cell count and protein concentration in aqueous humors. The histopathology of all the ocular structures (cornea, lens, sclera, choroid, retina, uvea, and anterior and posterior chambers) was also considered. Enzyme-linked immunosorbent assays of the aqueous humor samples were performed to quantify the levels of the different chemokine and cytokine proteins. Similarly, a biochemical analysis of oxidative stress-related markers was also assessed. The inflammation observed in the anterior chamber of the eyes when Daclizumab was administered with endotoxin was largely prevented since the aqueous humor protein concentration substantially lowered concomitantly with a significant reduction in the uveal and vitreous histopathological grading. Th1 lymphocytes-related cytokines, such as Interleukin-2 and Interferon-?, also significantly reduced with related anti-oxidant systems recovery. Daclizumab treatment in endotoxin-induced uveitis reduced Th1 lymphocytes-related cytokines, such as Interleukin-2 and Interferon gamma, by about 60–70% and presented a preventive role in endotoxin-induced oxidative stress. This antioxidant protective effect of Daclizumab may be related to several of the observed Daclizumab effects in our study, including IL-6 cytokine regulatory properties and a substantial concomitant drop in INF?. Concurrently, Daclizumab treatment triggered a significant reduction in both the uveal histopathological grading and protein concentration in aqueous humors, but not in cellular infiltration. PMID:24595020

Navea, Amparo; Almansa, Inmaculada; Muriach, María; Bosch-Morell, Francisco

2014-01-01

224

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

PubMed Central

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

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

2013-01-01

225

Top-Down Strategies for the Structural Elucidation of Intact Gram-negative Bacterial Endotoxins.  

PubMed

Re-modelling of lipopolysaccharides, which are the primary constituent of the outer cell membrane of Gram-negative bacteria, modulates pathogenesis and resistance to microbials. Reported herein is the characterization of intact Gram-negative bacterial lipooligosaccharides (LOS) via a new strategy utilizing online liquid chromatography (LC) coupled with ultraviolet photodissociation (UVPD) mass spectrometry. Compared to collision-based MS/MS methods, UVPD and UVPD/HCD promoted a greater array of cleavages within both the glycan and lipid moieties, including C-C, C-N, C-O cleavages in the acyl chains as well as glycosidic and cross-ring cleavages, thus providing the most far-reaching structural characterization of LOS. This LC-MS/MS strategy affords a robust analytical method to structurally characterize complex mixtures of bacterial endotoxins that maintains the integrity of the core oligosaccharide and lipid A domains of LOS, providing direct feedback about the cell envelope architectures and LOS modification strategies involved in resistance host innate immune defense. PMID:25386333

O'Brien, John P; Needham, Brittany D; Brown, Dusty B; Trent, M Stephen; Brodbelt, Jennifer S

2014-11-01

226

Relationship of tumour necrosis factor and endotoxin to macrophage cytotoxicity, haemorrhagic necrosis and lethal shock.  

PubMed

In this communication we discuss preliminary evidence suggesting a very strong synergism between tumour necrosis factor (TNF) and lipopolysaccharide (LPS) or between TNF and other bacteria in causing haemorrhagic necrosis and lethal shock. We found that TNF by itself does not cause haemorrhagic necrosis when injected into normal skin. TNF also had a rather low systemic toxicity when injected into disease-free, germfree-derived, defined-flora animals. On the other hand the addition of small amounts of LPS markedly raised the lethality of intravenous TNF treatments, and LPS injected into normal skin 'prepared' the site of injection for subsequent induction of haemorrhagic necrosis by locally injected TNF. Similar synergism was observed between TNF and mycoplasma. We suggest that the synergism between TNF and bacterial endotoxin (or other bacteria or bacterial products) may be part of an important defence mechanism against infections which is independent of specific immunity mediated by B and T cells. This synergism may be useful in increasing the therapeutic effects of TNF on tumours if the development of systemic toxicity in this treatment can be prevented. PMID:3330008

Rothstein, J L; Schreiber, H

1987-01-01

227

Distribution of bacterial endotoxin in human and rabbit blood and effects of stroma-free hemoglobin.  

PubMed Central

Bacterial endotoxin (lipopolysaccharide [LPS]) is known to interact with numerous components of blood, including erythrocytes, mononuclear cells, platelets, neutrophils, lipoproteins, and plasma proteins. The relative affinities of LPS for these elements, and the distribution of LPS between them, are unknown. Cross-linked stroma-free hemoglobin (SFH), a potential substitute for erythrocyte transfusion, produces in vivo toxicity in animals consistent with significant LPS contamination. Therefore, we studied the distribution of LPS in human and rabbit blood and examined whether the presence of SFH altered LPS distribution. In either the presence or absence of SFH, LPS was associated predominantly with high-density lipoproteins and apoproteins. There was lesser binding to low- and very-low-density lipoproteins. Examination of the apoprotein pool by column chromatography and density centrifugation demonstrated that LPS in this fraction was predominantly protein bound. Binding of LPS to SFH resulted in dissociation of a portion of the LPS into low-molecular-weight complexes. Cell-bound LPS was only 2 to 16% of the total and was unaffected by SFH. The distribution among blood cells demonstrated predominant binding to platelets in human blood but predominant binding to erythrocytes in rabbit blood. Cellular distribution was not significantly altered by SFH. PMID:8335351

Roth, R I; Levin, F C; Levin, J

1993-01-01

228

Cardiac Function and Circulating Cytokines Following Endotoxin Exposure in Neonatal Mice  

PubMed Central

Complications following cardiac surgery in neonates can occur due to activation of the inflammatory system. This study used lipopolysaccharide (LPS) endotoxin exposure to cause cytokine activation in neonatal mice and examine left ventricular (LV) function as well as the effects of antioxidant treatment on cytokine levels. Neonatal mice (6 day old) were injected with either 25 mg/kg LPS (n=13) or phosphate buffered saline (PBS, n=14) and LV function (echocardiography) was measured at 4 hours. Plasma levels of tumor necrosis factor-? (TNF-?), interleukin (IL)-4, IL-6, and IL-10 were measured at 30 min, 1, 2, and 4 hours after injection (n=5 mice per group). Effects of pretreatment with N-acetylcysteine (NAC, 50 mg/kg) on cytokine levels were examined at 2 and 4 hours following PBS or LPS (n=5 mice per group). Four hours after LPS heart rate was increased (434±14 vs. 405±14 bpm, p<0.05). LV end-diastolic dimension and ejection time were reduced with LPS (both p<0.05). LPS exposure increased plasma TNF-?, IL-6, and IL-10 levels. NAC pretreatment attenuated the increases in TNF-? and IL-6 levels, but augmented IL-10 levels at 2 hours post-LPS. LPS exposure altered cardiac performance and activated cytokines in neonatal mice, which may be ameliorated using antioxidants. PMID:20613681

Mukherjee, Rupak; McQuinn, Tim C.; Dugan, Melissa A.; Saul, J. Philip; Spinale, Francis G.

2011-01-01

229

An apple oligogalactan suppresses endotoxin-induced cyclooxygenase-2 expression by inhibition of LPS pathways.  

PubMed

Colorectal cancer (CRC) is one of the most common cancers and a leading cause of cancer-related mortality in developed countries. Many ingredients of apples have been proven to have anti-inflammatory and anti-carcinogenic characteristics, and show benefits for CRC prevention. The aim of this study, therefore, was to evaluate inhibitory effect of an apple oligogalactan (AOG) on pro-inflammatory endotoxin lipopolysaccharide (LPS)-activated human colon carcinoma cells HT-29 and SW-620 and investigate the possible mechanisms. The two cell lines were pretreated with AOG (0.1-1 g/L) for 30 min and then treated with 10 ?g/mL LPS. Real time PCR, Western blot, electrophoretic mobility shift assay (EMSA), and ELISA were used to detect the expression and activity of cyclooxygenase-2 (COX-2), NF-?B and MAPKs pathways. AOG significantly inhibited the expression and activity of COX-2 in LPS-activated human colon carcinoma cells HT-29 and SW-620. The mechanisms of AOG-suppressed COX-2 expression may be through inhibiting the phosphorylation of MAPKs and the activation of NF-?B and AP-1. These data may provide another molecular basis for understanding how apples act to prevent CRC and indicate that AOG may be useful for treatment of colitis and prevention of carcinogenesis. PMID:23827762

Li, Yuhua; Fan, Lei; Sun, Yang; Zhang, Dian; Yue, Zhenggang; Niu, Yinbo; Meng, Jin; Yang, Tiehong; Liu, Wenchao; Mei, Qibing

2013-10-01

230

Cultured human endothelial cells stimulated with cytokines or endotoxin produce an inhibitor of leukocyte adhesion.  

PubMed Central

Activation of cultured human endothelial cells (HEC) by inflammatory stimuli, such as interleukin 1 (IL-1), tumor necrosis factor (TNF), and bacterial endotoxin (lipopolysaccharide, LPS), increases their surface adhesiveness for blood leukocytes and related cell lines. We now report that activated HEC also generate a soluble leukocyte adhesion inhibitor (LAI), which accumulates in conditioned media from IL-1-, TNF-, or LPS-treated, but not sham-treated, HEC cultures. LAI significantly inhibits the adhesion of PMN and monocytes to activated, but not unactivated, HEC. In contrast, LAI has no effect on the adhesion of lymphocytes, the promyelocytic cell line HL-60 or the monocyte-like cell line U937 to HEC monolayers. LAI appears to act directly on the leukocyte, but does not inhibit either agonist-induced responses in PMN (membrane depolarization, changes in cytosolic calcium concentration, superoxide production) or PMN attachment to serum-coated plastic surfaces. Endothelial generation of LAI is blocked by actinomycin D but not by aspirin or indomethacin. Preliminary biochemical characterization indicates that LAI is a soluble, protein-containing molecule that is heat- and acid-stable. Fractionation by HPLC gel filtration yields a single peak of LAI activity (14,000 less than Mr greater than 24,000). Thus, in addition to proadhesive cell surface changes, the endothelium may also actively contribute to the regulation of endothelial-leukocyte interactions at sites of inflammation in vivo through the production of soluble adhesion inhibitors such as LAI. Images PMID:3049673

Wheeler, M E; Luscinskas, F W; Bevilacqua, M P; Gimbrone, M A

1988-01-01

231

White matter injury after repeated endotoxin exposure in the preterm ovine fetus.  

PubMed

Intrauterine infection has been linked to neurologic injury in preterm infants. However, a reproducible model of white matter injury in the preterm fetus in a long gestation species that can be monitored in utero is currently unavailable. Thus, our objective was to determine the effects of bacterial endotoxin (lipopolysaccharide, LPS) on physiologic and inflammatory responses and brain structure in the preterm ovine fetus. At 0.7 of gestation, six catheterized fetuses received three to five intravenous injections of LPS (1 micro g/kg) over 5 d; seven fetuses served as controls. Fetal responses were monitored and brain tissue examined 10-11 d after the initial LPS injection. After LPS on d 1 and 2, fetuses became transiently hypoxemic and hypotensive and blood IL-6 levels were increased, but these responses were smaller or absent after subsequent LPS exposures. Neural injury was observed in all LPS-exposed fetuses, most prominently in the cerebral white matter. Injury ranged from diffuse subcortical damage to periventricular leukomalacia, and in the brainstem the cross-sectional area of the corticospinal tract was reduced by 30%. Thus, repeated exposure of the preterm ovine fetus to LPS causes neuropathology resembling that of cerebral palsy and provides a robust model for exploring the etiology, prevention, and treatment of white matter damage. PMID:12438674

Duncan, Jhodie R; Cock, Megan L; Scheerlinck, Jean-Pierre Y; Westcott, Kerryn T; McLean, Catriona; Harding, Richard; Rees, Sandra M

2002-12-01

232

ALLERGEN PROVOCATION AUGMENTS ENDOTOXIN-INDUCED NASAL INFLAMMATION IN ATOPIC ASTHMATICS  

EPA Science Inventory

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

233

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

SciTech Connect

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

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

1984-08-01

234

Galactosamine-Induced Sensitization to the Lethal Effects of Endotoxin  

Microsoft Academic Search

Treatment of rabbits, rats, and mice with D-galactosamine increased their sensitivity to the lethal effects of lipopolysaccharide several thousand fold. The susceptibility of the animals was highest when the lipopolysacharide was injected together with galactosamine and decreased successively when injection was carried out 1, 2, and 3 hr later. Sensitization was absent when the lipopolysaccharide was administered 1 hr before

Chris Galanos; Marina A. Freudenberg; Werner Reutter

1979-01-01

235

Airborne endotoxin concentrations at a large open-lot dairy in southern Idaho  

Technology Transfer Automated Retrieval System (TEKTRAN)

Endotoxins are derived from Gram-negative bacteria and are a potential respiratory health risk for animals and humans. To determine the potential for endotoxin transport from a large open lot dairy, airborne endotoxin concentrations were determined at an upwind location (background) and five downwi...

236

Concentrations and Emissions of Airborne Endotoxins and Microorganisms in Livestock Buildings in Northern Europe  

Microsoft Academic Search

The concentration of airborne endotoxins and microorganisms in livestock buildings (cattle, pig, poultry) was surveyed in four European countries (England, The Netherlands, Denmark and Germany). Measurements were made during the day and night. The endotoxin concentrations were determined from dust samples separated into inhalable and respirable fractions. Airborne microorganisms were classified as total bacteria,Enterobacteriaceaeand total fungi.The lowest endotoxin concentrations were

J. Seedorf; J. Hartung; M. Schröder; K. H. Linkert; V. R. Phillips; M. R. Holden; R. W. Sneath; J. L. Short; R. P. White; S. Pedersen; H. Takai; J. O. Johnsen; J. H. M. Metz; P. W. G. Groot Koerkamp; G. H. Uenk; C. M. Wathes

1998-01-01

237

Indoor Determinants of Endotoxin and Dust Mite Exposures in Hong Kong Homes with Asthmatic Children  

Microsoft Academic Search

Background: Domestic endotoxin enhances airway inflammation and increases asthma severity in Caucasian children, but little data are published on indoor endotoxin exposure in Asian countries. This study investigated house dust endotoxin and Der p 1 levels in Hong Kong families with asthmatic children, and their effects on asthma severity. Methods: 115 asthmatics from a pediatric clinic underwent fractional exhaled nitric

Ting Fan Leung; Yun Sze Wong; Iris H. S. Chan; Edmund Yung; Chun Kwok Wong; Christopher W. K. Lam; Gary W. K. Wong

2010-01-01

238

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

PubMed

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

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

2014-04-01

239

Effect of lipopolysaccharide structure on reactivity of antiporin monoclonal antibodies with the bacterial cell surface.  

PubMed Central

We studied the reactivity of 66 anti-Escherichia coli B/r porin monoclonal antibodies (MAbs) with several E. coli and Salmonella typhimurium strains. Western immunoblots showed complete immunological cross-reactivity between E. coli B/r and K-12; among 34 MAbs which recognized porin in immunoblots of denatured outer membranes of E. coli B/r, all reacted with OmpF in denatured outer membranes of E. coli K-12. Extensive reactivity, although less than that for strain B/r (31 of 34 MAbs), occurred for porin from a wild-type isolate, E. coli O8:K27. Only one of the MAbs reacted with porin in denatured outer membranes of S. typhimurium. Even with immunochemical amplification of the Western immunoblot technique, only six MAbs recognized S. typhimurium porin (OmpD), demonstrating that there is significant immunological divergence between the porins of these species. Antibody binding to the bacterial surface, which was analyzed by cytofluorimetry, was strongly influenced by lipopolysaccharide (LPS) structure. An intact O antigen, as in E. coli O8:K27, blocked adsorption of all 20 MAbs in the test panel. rfa+ E. coli K-12, without an O antigen but with an intact LPS core, bound seven MAbs. When assayed against a series of rfa E. coli K-12 mutants, the number of MAbs that recognized porin surface epitopes increased sequentially as the LPS core became shorter. A total of 17 MAbs bound porin in a deep rough rfaD strain. Similar results were obtained with S. typhimurium. None of the anti-E. coli B/r porin MAbs adsorbed to a smooth strain, but three antibodies recognized porin on deep rough (rfaF, rfaE) mutants. These data define six distinct porin surface epitopes that are shielded by LPS from reaction with antibodies. Images PMID:2830227

Bentley, A T; Klebba, P E

1988-01-01

240

Shiga Toxin 1 Induces on Lipopolysaccharide-Treated Astrocytes the Release of Tumor Necrosis Factor-alpha that Alter Brain-Like Endothelium Integrity  

Microsoft Academic Search

The hemolytic uremic syndrome (HUS) is characterized by hemolytic anemia, thrombocytopenia and renal dysfunction. The typical form of HUS is generally associated with infections by Gram-negative Shiga toxin (Stx)-producing Escherichia coli (STEC). Endothelial dysfunction induced by Stx is central, but bacterial lipopolysaccharide (LPS) and neutrophils (PMN) contribute to the pathophysiology. Although renal failure is characteristic of this syndrome, neurological complications

Verónica I. Landoni; Pablo Schierloh; Marcelo de Campos Nebel; Gabriela C. Fernández; Cecilia Calatayud; María J. Lapponi; Martín A. Isturiz

2012-01-01

241

Bacterial lipopolysaccharides as inducers of disease resistance in tobacco.  

PubMed Central

The cell wall component of Pseudomonas solanacearum that induces disease resistance in tobacco was highly heat stable at neutral or alkaline pH but highly labile at acid pH. Activity was unaffected by nucleases and proteases but destroyed by a mixture of beta-glycosidases. Washing of bacterial cell walls released a lipopolysaccharide (LPS) fraction with high inducer activity. Purified LPS, extracted by a variety of procedures from whole cells, isolated cell walls, and culture filtrates of both smooth and rough forms of P. solanacearum, induced disease resistance in tobacco at concentrations as low as 50 microgram/ml. The LPS from the non-plant pathogens Escherichia coli B, E. coli K, and Serratia marcescens was also active. Cell wall protein, free phospholipid, and nucleic acids were not necessary for activity. Moreover, since LPS from rough forms was active, the O-specific polysaccharide of the LPS was not required for activity. Hydrolysis of the remaining core-lipid A linkage or deacylation of lipid A destroyed inducer activity. When injected into tobacco leaves, purified LPS attached to tobacco mesophyll cell walls and induced ultrastructural changes in the host cell similar to those induced by attachment of whole heat-killed bacteria. Images PMID:21613

Graham, T L; Sequeira, L; Huang, T S

1977-01-01

242

Activation of central muscarinic receptor type 1 prevents development of endotoxin tolerance in rat liver.  

PubMed

Endotoxin tolerance is a mechanism in which cells receiving low doses of endotoxin, enter a transient phase with less inflammatory response to the next endotoxin challenges. Central nervous system is known to modulate systemic inflammation through activation of the cholinergic system; however, the role of central anti-inflammatory pathway in pathophysiology of hepatic endotoxin tolerance is unknown. Our study was designed to assess the effect central muscarinic type 1 receptor (M1) activation on development of endotoxin tolerance in rat liver. Endotoxin tolerance was induced by daily intraperitoneal injection of endotoxin (1 mg/kg) for 5 days. Animals were randomly divided into two groups which received intracerebroventricular injection of either MCNA-343 (an M1 agonist, 5 ng/kg) or saline 1h after intraperitoneal injection of saline or endotoxin. The responsiveness to endotoxin was assessed by measuring hepatic MCP-1 (monocyte chemotactic protein-1), iNOS (inducible nitric oxide synthase) and TNF-? (tumor necrosis-?) mRNA expression 3h after intraperitoneal administration of endotoxin using quantitative RT-PCR. A significant reduction in hepatic expression of MCP-1, iNOS and TNF-? was observed in rats with 5 days endotoxin challenge in comparison with rats given a single dose of endotoxin. There was no significant difference in hepatic expression of MCP-1, iNOS or TNF-? between acute and chronic LPS-treated groups in rats given MCNA-343. Central MCNA-343 stimulation could prevent the induction of hepatic endotoxin tolerance in animals receiving repeated doses of endotoxin. This indicates that M1 cholinergic receptor activation in the central nervous system can modulate endotoxin tolerance in rat liver. PMID:25008070

Eftekhari, Golnar; Hajiasgharzadeh, Khalil; Ahmadi-Soleimani, S Mohammad; Dehpour, Ahmad R; Semnanian, Saeed; Mani, Ali R

2014-10-01

243

Antibiotic-induced release of endotoxin in chronically bacteriuric patients.  

PubMed Central

A novel in vivo model for the study of antibiotic-induced release of endotoxin from gram-negative bacteria is described. The model uses the chronically colonized urinary tracts of patients whose spinal cords have been injured. At baseline, the organisms were present in the range of 1 x 10(3) to 2 x 10(7) CFU/ml, and the concentration of endotoxin ranged from 2 x 10(-1) to 1 x 10(3) ng/ml in 44 studies. In 10 control studies, the concentration of endotoxin and the numbers of viable gram-negative bacteria over time changed by an average of less than 0.15 log10 units from the baseline values. At 2 h after antibiotic administration, the average decrease in CFU was 0.93 log10 units, and because antibiotics cause the release of endotoxin, an average increase in endotoxin concentration of 0.59 log10 units was noted in 21 studies with susceptible bacteria. Similar changes in response to antibiotic exposure were seen in studies with susceptible Pseudomonas bacteria in comparison with those seen in studies with susceptible members of the family Enterobacteriaceae. These results provide evidence that this novel model may be useful for comparing the effects of antibiotics with different modes of action, both as single agents and in combination, on the concentration of endotoxin in relation to changes in the numbers of bacteria, under conditions of bacterial replication and antibiotic exposure more closely resembling those found in vivo than is possible in other models. PMID:1804012

Hurley, J C; Louis, W J; Tosolini, F A; Carlin, J B

1991-01-01

244

Cloning and characterization of two Serratia marcescens genes involved in core lipopolysaccharide biosynthesis.  

PubMed Central

Bacteriocin 28b from Serratia marcescens binds to Escherichia coli outer membrane proteins OmpA and OmpF and to lipopolysaccharide (LPS) core (J. Enfedaque, S. Ferrer, J. F. Guasch, J. Tomás, and M. Requé, Can. J. Microbiol. 42:19-26, 1996). A cosmid-based genomic library of S. marcescens was introduced into E. coli NM554, and clones were screened for bacteriocin 28b resistance phenotype. One clone conferring resistance to bacteriocin 28b and showing an altered LPS core mobility in polyacrylamide gel electrophoresis was found. Southern blot experiments using DNA fragments containing E. coli rfa genes as probes suggested that the recombinant cosmid contained S. marcescens genes involved in LPS core biosynthesis. Subcloning, isolation of subclones and Tn5tac1 insertion mutants, and sequencing allowed identification of two apparently cotranscribed genes. The deduced amino acid sequence from the upstream gene showed 80% amino acid identity to the KdtA protein from E. coli, suggesting that this gene codes for the 3-deoxy-manno-octulosonic acid transferase of S. marcescens. The downstream gene (kdtX) codes for a protein showing 20% amino acid identity to the Haemophilus influenzae kdtB gene product. The S. marcescens KdtX protein is unrelated to the KdtB protein of E. coli K-12. Expression of the kdtX gene from S. marcescens in E. coli confers resistance to bacteriocin 28b. PMID:8824620

Guasch, J F; Piqué, N; Climent, N; Ferrer, S; Merino, S; Rubires, X; Tomas, J M; Regué, M

1996-01-01

245

Exposure to endotoxin during estrus alters the timing of ovulation and hormonal concentrations in cows.  

PubMed

The effect of intramammary (IMM) or intravenous (IV) administration of E. coli endotoxin (LPS), at the onset of estrus, at the time of ovulation was examined. Steroid and gonadotropin concentrations around ovulation were also determined. Lactating Holstein cows (n=33) were assigned to saline-controls (n=12) and treated with LPS-IV (0.5 microg/kg; n=13) or LPS-IMM (10 microg; n=8). Synchronized cows were observed continuously for estrus. LPS (or saline) was injected within 30 min from the onset of standing estrus, at peak estradiol concentrations. The typical rise of body temperature, somatic cell count, cortisol, and NAGase activity was noted. One-third of both LPS-IV- and LPS-IMM-treated cows were manifested by an extended estrus to ovulation (E-O) interval of around 75 h or did not ovulate, compared with about 30 h in the other 2/3 of LPS cows and all controls. Estradiol concentrations 24 h before and after LPS did not differ between groups. However, LPS-IV cows with extended intervals exhibited another estrus and an additional rise of estradiol followed by delayed ovulation. LPS-treated cows with a delayed E-O interval had low or delayed LH surge; two LPS-treated cows did not exhibit LH surge and did not ovulate. All control cows exhibited normal hormone levels. Delayed ovulation was associated with a delayed rise of luteal progesterone. The results indicated that exposing cows to endotoxin during estrus induced a decreased and delayed LH surge in one-third of the cows. This was associated with delayed ovulation, which reduces the chances of successful fertilization. PMID:18602682

Lavon, Y; Leitner, G; Goshen, T; Braw-Tal, R; Jacoby, S; Wolfenson, D

2008-10-01

246

Decreased hepatic peroxisome proliferator-activated receptor-? contributes to increased sensitivity to endotoxin in obstructive jaundice  

PubMed Central

AIM: To investigate the role of hepatic peroxisome proliferator-activated receptor-? (PPAR-?) in increased susceptibility to endotoxin-induced toxicity in rats with bile duct ligation during endotoxemia. METHODS: Male Sprague-Dawley rats were subjected to bile duct ligation (BDL). Sham-operated animals served as controls. DNA binding were determined by polymerase chain reaction, Western blotting analysis, and electrophoretic mobility shift assay, respectively. BDL and sham-operated rats received a non-lethal dose of intraperitoneal lipopolysaccharide (LPS) injection (3 mg/kg, i.p.). Additionally, the potential beneficial effects of the PPAR-? agonist rosiglitazone were determined in BDL and sham-operated rats treated with a non-lethal dose of LPS. Survival was assessed in BDL rats treated with a non-lethal dose of LPS and in sham-operated rats treated at a lethal dose of LPS (6 mg/kg, i.p.). RESULTS: PPAR-? activity in rats undergoing BDL was significantly lower than in the sham-controls. Hepatic PPAR-? gene expression was downregulated at both the mRNA and protein levels. In a parallel group, serum levels of pro-inflammatory cytokines were nearly undetectable in the sham-operated rats. When challenged with a non-lethal dose of LPS (3 mg/kg), the BDL rats had approximately a 2.4-fold increase in serum IL-6, a 2.7 fold increase in serum TNF-?, 2.2-fold increase in serum IL-1 and 4.2-fold increase in serum ALT. The survival rate was significantly lower as compared with that in sham-operated group. Additionally, rosiglitazone significantly reduced the concentration of TNF-?, IL-1?, IL-6 and ALT in sham-operated rats, but not in BDL rats, in response to LPS (3 mg/kg). Also, the survival was improved by rosiglitazone in sham-operated rats challenged with a lethal dose of LPS, but not in BDL rats, even with a non-lethal dose of LPS (3 mg/kg). CONCLUSION: Obstructive jaundice downregulates hepatic PPAR-? expression, which in turn may contribute to hypersensitivity towards endotoxin. PMID:22219595

Lv, Xin; Song, Jian-Gang; Li, Hong-Hai; Ao, Jun-Ping; Zhang, Ping; Li, Ye-Sheng; Song, Shao-Li; Wang, Xiang-Rui

2011-01-01

247

Differential acute phase immune responses by Angus and Romosinuano steers following an endotoxin challenge.  

PubMed

Our primary objective of this experiment was to evaluate potential genetic differences between two diverse Bos taurus breeds [Angus (AG) and Romosinuano (RO)] in response to an endotoxin challenge. Eighteen steers (n = 9 steers/breed; 299.4 ± 5.2 kg BW) were acclimated to environmentally controlled chambers maintained at thermoneutrality (19.7 °C) and then fitted with indwelling jugular catheters and rectal temperature (RT) recording devices 1 d before the endotoxin challenge. The next day, blood samples were collected at 30-min intervals from -2 to 8 h, and RT was measured continuously at 1-min intervals throughout the study. At time 0, all steers received an intravenous bolus injection of lipopolysaccharide (LPS; 2.5 ?g/kg BW). Serum samples were stored at -80 °C until analyzed for cortisol, proinflammatory cytokines [tumor necrosis factor-alpha (TNF-?), interleukin-1 beta (IL-1?), IL-6, and interferon gamma (IFN-?)], and acute phase proteins (serum amyloid A, acid soluble protein, ceruloplasmin, and ?-acid glycoprotein). Rectal temperatures increased in both breeds within 1 h after LPS, with RO producing a greater increase in RT than AG steers (P < 0.001). Serum cortisol and TNF-? increased (P < 0.01) in both breeds within 1 h after the LPS challenge. For cortisol, an overall breed effect (P < 0.02) was detected, such that AG steers had a higher cortisol response than RO steers. A breed × time interaction (P < 0.01) was observed for TNF-?, such that the response was delayed and extended in the RO steers compared with the AG steers. At 2 and 2.5 h after LPS, TNF-? concentrations were greater (P < 0.03) in RO steers than in AG steers. For IL-1?, a breed × time interaction (P < 0.04) was also observed. At 3 h after LPS, IL-1? concentrations were greater (P < 0.01) in RO steers than in AG steers. Serum IL-6 and IFN-? increased (P < 0.01) in a similar manner in both groups after the LPS challenge. These data show differences in the innate immune response between two diverse Bos taurus breeds which may provide insight about differences observed in productivity, heat tolerance, disease resistance, and longevity among cattle breeds. PMID:21865005

Carroll, J A; Burdick, N C; Reuter, R R; Chase, C C; Spiers, D E; Arthington, J D; Coleman, S W

2011-11-01

248

Propofol exerts protective effects on the acute lung injury induced by endotoxin in rats.  

PubMed

Acute lung injury (ALI) is a major culprit of mortality in endotoxemia. Propofol has been commonly used in critical ill patients for sedation. This experiment attempted to elucidate the effects and possible mechanisms of propofol on the ALI induced by endotoxin. Experimentations were carried out using anesthetized, ventilated rats and isolated perfused rat lungs. Endotoxemia was induced by intravenous lipopolysaccharide (LPS, 10 mg kg(-1)). Various groups of rats received infusion of physiological saline solution (PSS) and LPS. Five min after LPS, propofol at low dose (5 mg kg(-1)h(-1)) or high dose (10 mg kg(-1)h(-1)) was infused for 6h. In isolated perfused rat lungs, PSS, LPS, and propofol (30 or 60 mg kg(-1)) were added into the perfusion circuit. During or after 6h observation, we determined the lung weight (LW)/body weight ratio, LW gain, exhaled nitric oxide (NO) and protein concentration in broncheoalveolar lavage. Lung pathology was evaluated to quantify the lung injury score. Plasma nitrate/nitrite, methyl guanidine (MG), tumor necrosis factor(alpha), and interleukin-1(beta) were examined. Blood leukocytes were counted. Capillary filtration coefficient (K(fc)) was obtained in isolated perfused lungs. Posttreatment of propofol at low or high dose attenuated or prevented the extent of ALI. It also reduced the plasma nitrate/nitrite, MG, and pro-inflammatory cytokines including tumor necrosis factor(alpha) (TNF(alpha)) and interleukin-1(beta) (IL-1(beta)). In the isolated perfused rat lungs, propofol significantly reduced the LPS-induced increase in K(fc). This agent did not affect the leukocytopenia caused by LPS. Accordingly, the effects of propofol on the ALI were not related to leukocyte activation or sequestration. Our results suggest that propofol exerts protective effect on the endotoxin-induced ALI. The mechanisms of actions may be mediated through inhibition on the release of pro-inflammatory cytokines, free radicals and NO. In addition, propofol abrogates the microvascular leakage of water and protein in the lungs. The results imply that the use of propofol in critically ill is not only for sedation, but also useful for the prevention of inflammatory progression and lung damage. PMID:16713316

Chu, Chia-Hsiang; David Liu, Demeral; Hsu, Yung-Hsiang; Lee, Kuan-Chiao; Chen, Hsing I

2007-01-01

249

Effect of bovine leukemia virus infection on bovine peripheral blood monocyte responsiveness to lipopolysaccharide stimulation in vitro  

Microsoft Academic Search

The effects of bovine leukemia virus (BLV) infection on cytokine activity of bovine monocytes stimulated with Escherichia coli lipopolysaccharide (LPS) were examined. Compared to supernatants of LPS-stimulated monocytes from BLV-negative cows, supernatants from BLV-positive cows contained about four times more interleukin-1? (IL-1?) (as measured by an enzyme-linked immunosorbent assay (ELISA) for bovine IL-1?). Despite their higher IL-1? concentration, supernatants from

D. Werling; M. Sileghem; H. Lutz; W. Langhans

1995-01-01

250

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

Microsoft Academic Search

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

Elisabeth Elass; Maryse Masson; Joël Mazurier; Dominique Legrand

2002-01-01

251

Isolation of Shiga Toxin-Producing Escherichia coli from a South American Camelid (Lama guanicoe) with Diarrhea  

PubMed Central

Shiga toxin-producing Escherichia coli belonging to serotype O26:H11 was isolated from a 2-month-old guanaco with severe watery diarrhea. E. coli colonies carried the stx1 and eae genes, showed localized adherence to HEp-2 cells, and produced enterohemolysin. A serological response to lipopolysaccharide O26 was observed at the onset of diarrhea. PMID:15472347

Mercado, E. C.; Rodríguez, S. M.; Elizondo, A. M.; Marcoppido, G.; Parreńo, V.

2004-01-01

252

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

PubMed Central

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

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

2013-01-01

253

Crystal structure of an endotoxin-neutralizing protein from the horseshoe crab, Limulus anti-LPS factor, at 1.5 A resolution.  

PubMed Central

Lipopolysaccharide (LPS), or endotoxin, is the major mediator of septic shock, a serious complication of Gram-negative bacterial infections in humans. Molecules that bind LPS and neutralize its biological effects or enhance its clearance could have important clinical applications. Limulus anti-LPS factor (LALF) binds LPS tightly, and, in animal models, reduces mortality when administered before or after LPS challenge or bacterial infection. Here we present the high resolution structure of a recombinant LALF. It has a single domain consisting of three alpha-helices packed against a four-stranded beta-sheet. The wedge-shaped molecule has a striking charge distribution and amphipathicity that suggest how it can insert into membranes. The binding site for LPS probably involves an extended amphipathic loop, and we propose that two mammalian LPS-binding proteins will have a similar loop. The amphipathic loop structure may be used in the design of molecules with therapeutic properties against septic shock. Images PMID:8253062

Hoess, A; Watson, S; Siber, G R; Liddington, R

1993-01-01

254

Interleukin-1 induction by lipopolysaccharides: structural requirements of the 3-deoxy-D-manno-2-octulosonic acid (KDO).  

PubMed

We previously showed the importance of the 3-deoxy-D-manno-2-octulosonic acid (KDO) residue in endotoxins (lipopolysaccharides, LPS) for the induction of the synthesis and release of interleukin-1 (IL-1) by human monocytes. We further investigated the effect of some structural variations within the KDO molecule on IL-1 production induced by LPS. Deamination of Bordetella pertussis LPS, followed by mild anhydrous acidic methanolysis released a hexasaccharide (fragment B'), which had a terminal methyl ketoside KDO residue with a methyl-esterified carboxyl group. This fragment was unable to induce IL-1 production by human monocytes. Fragment B' could be converted into an active hexasaccharide by de-esterification (fragment B-OMe), but not by reduction of the methyl ester group. The KDO residues in the LPS of some bacterial species have been shown to be phosphorylated and we observed that these LPS were weak IL-1 inducers. Phosphorylated KDO present in Vibrio cholerae and B. pertussis LPS respond poorly in the thiobarbiturate assay (specific for KDO). However, if these LPS were dephosphorylated with aqueous hydrofluoric acid (HF) their KDO response in this assay was increased 5.4- to 2.6-fold, respectively. In parallel, the HF-treated LPS were more potent IL-1 inducers than untreated endotoxins. These data confirm that the KDO residue(s) present in all endotoxins play(s) a major role in the signal(s) leading to IL-1 production by human monocytes, and show that IL-1 induction by LPS (1) requires a free carboxyl group in the KDO and (2) is correlated with the degree of substitution of the KDO. PMID:2549403

Haeffner-Cavaillon, N; Caroff, M; Cavaillon, J M

1989-05-01

255

The anti-idiotypic antibody 1F7 stimulates monocyte interleukin-10 production and induces endotoxin tolerance  

PubMed Central

Background Pathogens that establish chronic infection elicit immune responses with suppressive cytokines dominating over pro-inflammatory cytokines. Chronic hepatitis C virus (HCV) infection, human immunodeficiency virus (HIV) infection and simian immunodeficiency virus (SIV) infection are associated with high levels of antiviral antibodies expressing a common idiotype specifically recognized by the 1F7 monoclonal antibody (mAb). The 1F7 mAb is a murine IgM? antibody raised against immunoglobulin pooled from the plasma of multiple HIV-infected individuals. In this study, we investigated direct effects of the 1F7 mAb itself on peripheral blood mononuclear cells (PBMC). Methods Isolated monocytes or PBMC from healthy controls were incubated with the 1F7 mAb or IgM? mAb control. Cytokine production was measured in cell culture supernatants by ELISA and cells producing interleukin-10 (IL-10) were identified by subset depletion and intracellular flow cytometry. Endotoxin tolerance was assessed by exposing monocytes to lipopolysaccharide (LPS) following 1F7 mAb or IgM? mAb control pre-treatment and comparing tumor necrosis factor (TNF)-? levels in cell culture supernatants. Results The 1F7 mAb stimulated monocytes and CD36+ lymphocytes to produce IL-10 in a time and dose-dependent manner. Treatment of monocytes with 1F7 mAb also reduced their subsequent responsiveness to LPS stimulation. Conclusions Induction of antibodies expressing the 1F7 idiotype by chronic pathogens may facilitate IL-10 production and progression to chronic infection. Direct effects of IL-10 from human monocytes stimulated by 1F7-like antibodies, followed by monocyte transition to an alternatively activated phenotype illustrated by endotoxin tolerance, are two complementary features favouring a tolerogenic or non-responsive immunological environment. PMID:23561395

2013-01-01

256

N-Linked Glycosylation Is Required for C1 Inhibitor-Mediated Protection from Endotoxin Shock in Mice  

PubMed Central

C1 inhibitor (C1INH) prevents endotoxin shock in mice via a direct interaction with lipopolysaccharide (LPS). This interaction requires the heavily glycosylated amino-terminal domain of C1INH. C1INH in which N-linked carbohydrate was removed by using N-glycosidase F was markedly less effective in protecting mice from LPS-induced lethal septic shock. N-deglycosylated C1INH also failed to suppress fluorescein isothiocyanate (FITC)-LPS binding to and LPS-induced tumor necrosis factor alpha mRNA expression by the murine macrophage-like cell line, RAW 264.7, and cells in human whole blood. In an enzyme linked immunosorbent assay, the N-deglycosylated C1INH bound to LPS very poorly. In addition, C1INH was shown to bind to diphosphoryl lipid A (dLPA) but only weakly to monophosphoryl lipid A (mLPA). As with intact LPS, binding of N-deglycosylated C1INH to dLPA and mLPA was diminished in comparison with the native protein. Removal of O-linked carbohydrate had no effect on any of these activities. Neither detoxified LPS, dLPA, nor mLPA had any effect on the rate or extent of C1INH complex formation with C1s or on cleavage of the reactive center loop by trypsin. These data demonstrate that N-linked glycosylation of C1INH is essential to mediate its interaction with the LPA moiety of LPS and to protect mice from endotoxin shock. PMID:15039314

Liu, Dongxu; Gu, Xiaogang; Scafidi, Jennifer; Davis, Alvin E.

2004-01-01

257

N-linked glycosylation is required for c1 inhibitor-mediated protection from endotoxin shock in mice.  

PubMed

C1 inhibitor (C1INH) prevents endotoxin shock in mice via a direct interaction with lipopolysaccharide (LPS). This interaction requires the heavily glycosylated amino-terminal domain of C1INH. C1INH in which N-linked carbohydrate was removed by using N-glycosidase F was markedly less effective in protecting mice from LPS-induced lethal septic shock. N-deglycosylated C1INH also failed to suppress fluorescein isothiocyanate (FITC)-LPS binding to and LPS-induced tumor necrosis factor alpha mRNA expression by the murine macrophage-like cell line, RAW 264.7, and cells in human whole blood. In an enzyme linked immunosorbent assay, the N-deglycosylated C1INH bound to LPS very poorly. In addition, C1INH was shown to bind to diphosphoryl lipid A (dLPA) but only weakly to monophosphoryl lipid A (mLPA). As with intact LPS, binding of N-deglycosylated C1INH to dLPA and mLPA was diminished in comparison with the native protein. Removal of O-linked carbohydrate had no effect on any of these activities. Neither detoxified LPS, dLPA, nor mLPA had any effect on the rate or extent of C1INH complex formation with C1s or on cleavage of the reactive center loop by trypsin. These data demonstrate that N-linked glycosylation of C1INH is essential to mediate its interaction with the LPA moiety of LPS and to protect mice from endotoxin shock. PMID:15039314

Liu, Dongxu; Gu, Xiaogang; Scafidi, Jennifer; Davis, Alvin E

2004-04-01

258

[Shigella endotoxin protein--its isolation and physicochemical characteristics].  

PubMed

The scheme of the isolation of endotoxic protein from S. sonnei 9090 is presented. The isolation procedure includes the 10-minute hot (at 68 degrees C) extraction of protein from endotoxin with 45% aqueous phenol, the precipitation of protein from phenolic extract with 9.5 volumes of 95% ethanol, the purification of protein from lipid material and pigments by multiple extraction with the mixture of chloroform and ethanol in the proportion 2:1 by volume. The yield of protein obtained with the use of this isolation scheme is about 3% of the initial endotoxin preparation. Protein preparations obtained in accordance with this scheme contain 92-95% of protein (determined by Lowry's method), 2.3-3.0% of saccharides (determined by the phenol-sulfate method) and 0.02% of hexose amine, its presence indicating that the preparations contain lipid A (or its fragments) which is firmly bound with endotoxic protein and cannot be extracted with chloroform. As shown in the passive hemagglutination inhibition test, the content of endotoxin in the preparations is less than 0.003%. Out of 7-11 bands revealed by electrophoresis in 15% polyacrylamide gel in the presence of sodium dodecyl sulfate, 3 main bands have molecular weights of 43, 38 and 18 KD. Three antigens differing in their electrophoretic mobility and diffusion rate in 1% agarose gel can be detected in the preparations by the method of immunoelectrophoresis with the use of antisera to both endotoxin and endotoxic protein. PMID:1882598

Egorova, T P; Nartikova, V F; Belkin, Z P; Fedosova, V G; Levenson, V I

1991-04-01

259

Original article Local and systemic effects of endotoxin mastitis  

E-print Network

Original article Local and systemic effects of endotoxin mastitis on the chemiluminescence of milk lactation cows. Clinical signs of acute mastitis such as fever, increased heart rate and a decreased milk-induced mastitis. In contrast, the MPO-H2O2 system was enhanced in milk PMN from chal- lenged quarters. The highest

Paris-Sud XI, Université de

260

Original article Neutrophil recruitment in endotoxin-induced murine  

E-print Network

Original article Neutrophil recruitment in endotoxin-induced murine mastitis is strictly dependent (Received 14 July 2009; accepted 7 October 2009) Abstract ­ Mastitis, inflammation of the mammary tissue signaling and (ii) is dependent on IL8 and IL1b signaling and regulated by iNOS-derived NO. mastitis

Paris-Sud XI, Université de

261

Research paper Simultaneous metal chelate affinity purification and endotoxin  

E-print Network

and functionality of these multimeric molecules. Furthermore, recombinant antibody fragments did not stimulate). Endotoxin induces the activation of monocytes, macro- phages (Gao and Tsan, 2003b) and endothelial cells (Munshi et al., 2002). LPS-activated cells release mediators such as pro-inflammatory cytokines, TNF

Lebendiker, Mario

262

Original article The effect of endotoxin-contaminated medium  

E-print Network

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

Paris-Sud XI, Université de

263

Alteco endotoxin hemoadsorption in Gram-negative septic shock patients  

PubMed Central

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

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

2014-01-01

264

Restriction map of the 125-kilobase plasmid of Bacillus thuringiensis subsp. israelensis carrying the genes that encode delta-endotoxins active against mosquito larvae.  

PubMed Central

A large plasmid containing all delta-endotoxin genes was isolated from Bacillus thuringiensis subsp. israelensis; restricted by BamHI, EcoRI, HindIII, KpnI, PstI, SacI, and SalI; and cloned as appropriate libraries in Escherichia coli. The libraries were screened for inserts containing recognition sites for BamHI, SacI, and SalI. Each was labeled with 32P and hybridized to Southern blots of gels with fragments generated by cleaving the plasmid with several restriction endonucleases, to align at least two fragments of the relevant enzymes. All nine BamHI fragments and all eight SacI fragments were mapped in two overlapping linkage groups (with total sizes of about 76 and 56 kb, respectively). The homology observed between some fragments is apparently a consequence of the presence of transposons and repeated insertion sequences. Four delta-endotoxin genes (cryIVB-D and cytA) and two genes for regulatory polypeptides (of 19 and 20 kDa) were localized on a 21-kb stretch of the plasmid; without cytA, they are placed on a single BamHI fragment. This convergence enables subcloning of delta-endotoxin genes (excluding cryIVA, localized on the other linkage group) as an intact natural fragment. PMID:8795201

Ben-Dov, E; Einav, M; Peleg, N; Boussiba, S; Zaritsky, A

1996-01-01

265

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

PubMed

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

Douhara, Akitoshi; Moriya, Kei; Yoshiji, Hitoshi; Noguchi, Ryuichi; Namisaki, Tadashi; Kitade, Mitsuteru; Kaji, Kosuke; Aihara, Yosuke; Nishimura, Norihisa; Takeda, Kosuke; Okura, Yasushi; Kawaratani, Hideto; Fukui, Hiroshi

2015-03-01

266

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

PubMed Central

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

DOUHARA, AKITOSHI; MORIYA, KEI; YOSHIJI, HITOSHI; NOGUCHI, RYUICHI; NAMISAKI, TADASHI; KITADE, MITSUTERU; KAJI, KOSUKE; AIHARA, YOSUKE; NISHIMURA, NORIHISA; TAKEDA, KOSUKE; OKURA, YASUSHI; KAWARATANI, HIDETO; FUKUI, HIROSHI

2015-01-01

267

Zinc Finger Protein Gfi1 Controls the Endotoxin-Mediated Toll-Like Receptor Inflammatory Response by Antagonizing NF-?B p65?  

PubMed Central

Endotoxin (bacterial lipopolysaccharide [LPS]) causes fatal septic shock via the Toll-like receptor 4 (TLR-4) protein present on innate immunity effector cells, which activates nuclear factor kappa B (NF-?B), inducing proinflammatory cytokines, including tumor necrosis factor alpha (TNF-?). An early step in this process involves nuclear sequestration of the p65-RelA NF-?B subunit, enabling transcriptional activation of target inflammatory cytokine genes. Here, we analyzed the role of the nuclear zinc finger protein Gfi1 in the TLR response using primary bone marrow-derived macrophages. We show that upon LPS stimulation, expression of Gfi1 is induced with kinetics similar to those of nuclear translocation of p65 and that Gfi1 interacts with p65 and inhibits p65-mediated transcriptional transactivation by interfering with p65 binding to target gene promoter DNA. Gfi1-deficient macrophages show abnormally high mRNA levels of the TNF-? gene and many other p65 target genes and a higher rate of TNF promoter occupancy by p65 than wild-type cells after LPS stimulation, suggesting that Gfi1 functions as an antagonist of NF-?B activity at the level of promoter binding. Our findings identify a new function of Gfi1 as a general negative regulator of the endotoxin-initiated innate immune responses, including septic shock and possibly other severe inflammatory diseases. PMID:20547752

Sharif-Askari, Ehssan; Vassen, Lothar; Kosan, Christian; Khandanpour, Cyrus; Gaudreau, Marie-Claude; Heyd, Florian; Okayama, Taro; Jin, Jianmin; Rojas, Meghan E. B.; Grimes, H. Leighton; Zeng, Hui; Möröy, Tarik

2010-01-01

268

Endotoxins in indoor air and settled dust in primary schools in a subtropical climate.  

PubMed

Endotoxins can significantly affect the air quality in school environments. However, there is currently no reliable method for the measurement of endotoxins, and there is a lack of reference values for endotoxin concentrations to aid in the interpretation of measurement results in school settings. We benchmarked the "baseline" range of endotoxin concentration in indoor air, together with endotoxin load in floor dust, and evaluated the correlation between endotoxin levels in indoor air and settled dust, as well as the effects of temperature and humidity on these levels in subtropical school settings. Bayesian hierarchical modeling indicated that the concentration in indoor air and the load in floor dust were generally (<95th percentile) <13 EU/m(3) and <24,570 EU/m(2), respectively. Exceeding these levels would indicate abnormal sources of endotoxins in the school environment and the need for further investigation. Metaregression indicated no relationship between endotoxin concentration and load, which points to the necessity for measuring endotoxin levels in both the air and settled dust. Temperature increases were associated with lower concentrations in indoor air and higher loads in floor dust. Higher levels of humidity may be associated with lower airborne endotoxin concentrations. PMID:23927534

Salonen, Heidi; Duchaine, Caroline; Létourneau, Valérie; Mazaheri, Mandana; Clifford, Sam; Morawska, Lidia

2013-09-01

269

Endotoxin levels in homes and classrooms of Dutch school children and respiratory health.  

PubMed

Several studies describe indoor pollutant exposure in homes and to a lesser extent in schools. Population studies that include both environments are sparse. This study aims to assess endotoxin levels in primary schools and homes of children. Endotoxin was also studied in relation to asthma and sensitisation. 10 schools with (index) and without (reference) dampness were selected, based on reports and inspections. Cases and controls were selected from 169 homes based on the presence or absence of asthma-like symptoms of children. Classroom and bedroom airborne settled dust was sampled using electrostatic dust fall collectors. Average endotoxin levels in schools ranged from 2178 to 6914 endotoxin units (EU)·m(-2) per week compared with 462-1285 EU·m(-2) per week in homes. After mutual adjustment for home and school endotoxin, school endotoxin was positively associated with nonatopic asthma (OR 1.11, 95% CI 0.97-1.27), while no associations with endotoxin were found at home. The high endotoxin levels in schools compared with homes indicate that exposure at school can contribute considerably to environmental endotoxin exposure of children and teachers. Our results also suggest that endotoxin in schools may be associated with nonatopic asthmatic symptoms in pupils, although the results require reproduction because of the modest sample size. PMID:23100494

Jacobs, José H; Krop, Esmeralda J M; de Wind, Siegfried; Spithoven, Jack; Heederik, Dick J J

2013-08-01

270

Endotoxin inactivation via steam-heat treatment in dilute simethicone emulsions used in biopharmaceutical processes.  

PubMed

Simethicone emulsion is used to regulate foaming in cell culture operations in biopharmaceutical processes. It is also a potential source of endotoxin contamination. The inactivation of endotoxins in dilute simethicone emulsions was assessed as a function of time at different steam temperatures using a Limulus amebocyte lysate kinetic chromogenic technique. Endotoxin inactivation from steam-heat treatment was fit to a four-parameter double exponential decay model, which indicated that endotoxin inactivation was biphasic, consisting of fast and slow regimes. In the fast regime, temperature-related effects were dominant. Transitioning into the slow regime, the observed temperature dependence diminished, and concentration-related effects became increasingly significant. The change in the Gibbs free energy moving through the transition state indicated that a large energy barrier must be overcome for endotoxin inactivation to occur. The corresponding Arrhenius pre-exponential factor was >10(12) s(-1) suggesting that endotoxins in aqueous solution exist as aggregates. The disorder associated with the endotoxin inactivation reaction pathway was assessed via the change in entropy moving through the transition state. This quantity was positive indicating that endotoxin inactivation may result from hydrolysis of individual endotoxin molecules, which perturbs the conformation of endotoxin aggregates, thereby modulating the biological activity observed. Steam-heat treatment decreased endotoxin levels by 1-2 logarithm (log) reduction (LRV), which may be practically relevant depending on incoming raw material endotoxin levels. Antifoam efficiency and cell culture performance were negligibly impacted following steam-heat treatment. The results from this study show that steam-heat treatment is a viable endotoxin control strategy that can be implemented to support large-scale biopharmaceutical manufacturing. PMID:24623631

Britt, Keith A; Galvin, Jeffrey; Gammell, Patrick; Nti-Gyabaah, Joseph; Boras, George; Kolwyck, David; Ramirez, José G; Presente, Esther; Naugle, Gregory

2014-01-01

271

Delayed myocardial protection induced by endotoxin does not involve kinin B(1)-receptors.  

PubMed

Endotoxin is known to confer a delayed protection against myocardial infarction. Lipopolysaccharide (LPS) treatment also induces the de novo synthesis of kinin B(1)-receptors that are not present in normal conditions. The aim of this study was to evaluate whether LPS-induced B(1)-receptors are implicated in the reduction of infarct size brought about by LPS. Rabbits were submitted to a 30-min coronary artery occlusion and 3-h reperfusion sequence. Six groups were studied: pretreated or not (control animals) with LPS (5 microgram kg(-1) i.v.) 24 h earlier and treated 15 min before and throughout ischaemia - reperfusion with either the B(1)-antagonist R-715 (1 mg kg(-1) h(-1)), the B(1)-agonist Sar-[D-Phe(8)]-des-Arg(9)-bradykinin (15 microgram kg(-1) h(-1)) or vehicle (saline). Infarct size and area at risk were assessed by differential staining and planimetric analysis. The presence of B(1)-receptors in LPS-pretreated animals was confirmed by a decrease in mean arterial pressure in response to B(1) stimulation. LPS-pretreatment significantly reduced infarct size (6.4+/-1.7%, of area at risk vs 24.1+/-2.5% in control animals, P<0.05). This protection was not modified by B(1)-receptor antagonism (7.4+/-2.2%, NS) or stimulation (5.2+/-1.2%, NS). Neither antagonist nor agonist modified infarct size in control animals. In conclusion, these data suggest that LPS-induced myocardial protection in the rabbit is not related to concomitant de novo B(1)-receptor induction. PMID:11030723

Mazenot, C; Gobeil, F; Ribuot, C; Regoli, D; Godin-Ribuot, D

2000-10-01

272

Prevention of Endotoxin-Induced Uveitis in Rats by Plant Sterol Guggulsterone  

PubMed Central

Purpose. To investigate the anti-inflammatory effects of guggulsterone, an antioxidant and antitumor agent, in endotoxin-induced uveitis (EIU) in rats and to elucidate the underlying molecular mechanism or mechanisms related to ocular inflammation. Methods. EIU was induced by subcutaneous injection of lipopolysaccharide (LPS; 150 ?g) into Lewis rats treated with guggulsterone (30 mg/kg body weight, intraperitoneally) or its carrier. After 24 hours the rats were killed, eyes were enucleated, and aqueous humor (AqH) was collected. Numbers of infiltrating cells and levels of matrix metalloproteinase-2 (MMP-2), nitric oxide (NO), and prostaglandin E2 (PGE2) were determined in AqH by specific ELISAs. An antibody array was used to measure the expression of various inflammatory cytokines in AqH. The expression of MMP-2, iNOS, Cox-2, phospho-I?B, and phospho-NF-?B was determined immunohistochemically. Human primary nonpigment ciliary epithelial cells (HNPECs) were used to determine the in vitro efficacy of guggulsterone on the LPS-induced inflammatory response. Results. Compared with control, the EIU rat eye AqH had a significantly higher number of infiltrating cells, total protein, and inflammatory markers, such as MMP-2, NO, and PGE2, and the treatment of guggulsterone prevented EIU-induced increases. Guggulsterone also prevented the expression of MMP-2, iNOS, and Cox-2 proteins and of I?B and NF-?B in various eye tissues. Moreover, in cultured HNPECs, guggulsterone inhibited LPS-induced expression of inflammatory proteins. Conclusions. These results for the first time demonstrate that the plant sterol guggulsterone suppresses ocular inflammation in EIU, suggesting that the supplementation of guggulsterone could be a novel approach for the treatment of ocular inflammation. PMID:20435582

Kalariya, Nilesh M.; Shoeb, Mohammad; Reddy, Aramati B. M.; Zhang, Min; van Kuijk, Frederik J. G. M.

2010-01-01

273

Application of thrombelastography in liver injury induced by endotoxin in rat.  

PubMed

Liver injury developing in patients with sepsis may lead to an increased risk of mortality. Thrombelastography (TEG) is generally applied to evaluate hemostatic disturbance in patients undergoing liver transplantation or cardiopulmonary bypass. The aim of this study was to investigate the development of liver injury and coagulopathy in a lipopolysaccharide (LPS)-induced animal model and to assess the relationship between TEG variables and liver injury. Male Wistar rats received LPS (30 ?mg/kg over a 4-h intravenous infusion) to induce experimental liver injury or isotonic saline as a control. Variables of hemodynamics and liver biochemistry were measured during the subsequent 6?h after the start of infusion. TEG variables (R-time, K-time, ?-angle and maximal amplitude), thrombin-antithrombin complex and plasminogen activator inhibitor-1 were also measured. After LPS infusion, liver injury [examined by biochemical variables (e.g. alanine aminotransferase, ALT) and histological studies] was developed and inflammatory cytokines (tumor necrosis factor-? and interleukin-6) were raised. At the initial period of LPS infusion, R-time was shortened and ?-angle was increased. Thereafter, ?-angle and maximal amplitude were decreased progressively, demonstrating that endotoxin induced coagulation disturbances. Furthermore, there were strong positive correlation between K-time and natural log (Ln)(ALT) (r?=?0.823, P?=?0.001); also, there were strong negative correlations between ?-angle and Ln(ALT) (r?=?-0.762, P?=?0.002) as well as maximal amplitude and Ln(ALT) (r?=?-0.732, P?=?0.004) at 6?h after LPS infusion. These results demonstrated that TEG could be a potential tool to evaluate the development of liver injury in endotoxemia. PMID:22227956

Tsai, Hsin-Jung; Tsao, Cheng-Ming; Liao, Mei-Hui; Ka, Shuk-Man; Liaw, Wen-Jinn; Wu, Chin-Chen

2012-03-01

274

Mast cells modulate the inflammatory process in endotoxin-induced uveitis  

PubMed Central

Purpose To investigate the role of mast cells and annexin-A1 (Anxa1) in endotoxin-induced uveitis (EIU). Methods EIU was induced by injection of lipopolysaccharide (LPS) into the paws of rats, which were then sacrificed after 24 and 48 h. To assess EIU in the absence of mast cells, groups of animals were pretreated with compound 48/80 (c48/80) and sacrificed after 24 h after no treatment or EIU induction. The eyes were used for histological studies and the aqueous humor (AqH) pool was used for the analysis of transmigrated cells and Anxa1 levels. In inflammatory cells, Anxa1 expression was monitored by immunohistochemistry. Results After 24 h, rats with EIU exhibited degranulated mast cells, associated with elevated numbers of infiltrating leukocytes and the high expression of Anxa1 in the AqH and the neutrophils. After 48 h of EIU, the mast cells were intact, indicating granule re-synthesis, and there was a reduction of neutrophil transmigration and an increase in the number of mononuclear phagocytic cells in ocular tissues. Anxa1 expression was decreased in neutrophils but increased in mononuclear phagocytic cells. In the animals pretreated with c48/80 and subjected to EIU, mast cells responded to this secretagogue by degranulating and few transmigrated neutrophils were observed. Conclustions We report that mast cells are a potential source of pharmacological mediators that are strongly linked to the pathophysiology of EIU, and the endogenous protein Anxa1 is a mediator in the homeostasis of the inflammatory process with anti-migratory effects on leukocytes, which supports further studies of this protein as an innovative therapy for uveitis. PMID:21633711

Sebastiăo da Silva, Pierre; Girol, Ana Paula

2011-01-01

275

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

PubMed Central

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

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

2014-01-01

276

Moesin Functions as a Lipopolysaccharide Receptor on Human Monocytes  

PubMed Central

Bacterial endotoxin (lipopolysaccharide [LPS]), a glycolipid found in the outer membranes of gram-negative bacteria, induces the secretion of proinflammatory cytokines such as tumor necrosis factor alpha (TNF-?), interleukin-1 (IL-1), and IL-6 by monocytes/macrophages. The secretion of these biologically active compounds leads to multiple pathological conditions, such as septic shock. There is substantial evidence that chronic exposure to LPS mediates, at least in part, the tissue destruction associated with gram-negative infection. CD14, a 55-kDa protein, has been identified as an LPS receptor. In conjunction with a serum protein, LPS binding protein (LBP), LPS-CD14 interactions mediate many LPS functions in the inflammatory response. However, CD14 lacks a cytoplasmic domain, or any known signal transduction sequence motif, suggesting the existence of another cell surface domain capable of transducing signals. In this paper, we report a second, CD14-independent LPS binding site, which, based on biological activity, appears to be a functional LPS receptor. Cross-linking experiments were performed to identify LPS binding sites. Two molecules were identified: a 55-kDa protein (CD14) and a second, 78-kDa band. Sequencing of the 78-kDa protein by mass spectroscopic analysis revealed 100% homology with moesin (membrane-organizing extension spike protein). Antibody to CD14 induced partial blocking of the LPS response. However, antimoesin monoclonal antibody completely blocked the LPS-induced TNF-? response in human monocytes, without blocking CD14 binding of LPS. Irrelevant isotype controls had no effect. Additional experiments were performed to evaluate the specificity of the antimoesin blocking. Separate experiments evaluated antimoesin effects on monocyte chemotaxis, IL-1 production in response to IL-1 stimulation, and TNF-? secretion in response to Staphylococcus aureus stimulation. Antimoesin blocked only LPS-mediated events. The data suggest that moesin functions as an independent LPS receptor on human monocytes. The role of moesin in transduction of CD14-mediated signals is discussed. PMID:10377093

Tohme, Ziad N.; Amar, Salomon; Van Dyke, Thomas E.

1999-01-01

277

Invited review: Bacterial lipopolysaccharides and innate immunity  

Microsoft Academic Search

Bacterial lipopolysaccharides (LPS) are the major outer surface membrane components present in almost all Gram-negative bacteria and act as extremely strong stimulators of innate or natural immunity in diverse eukaryotic species ranging from insects to humans. LPS consist of a poly- or oligosaccharide region that is anchored in the outer bacterial membrane by a specific carbohydrate lipid moiety termed lipid

Christian Alexander; Ernst Th. Rietschel

2001-01-01

278

Exposure to airborne microorganisms and endotoxin in herb processing plants.  

PubMed

Microbiological air sampling was performed in two herb processing plants located in eastern Poland. Air samples for determination of the levels of bacteria, fungi, dust and endotoxin were collected at 14 sites during cleaning, cutting, grinding, sieving, sorting and packing of 11 kinds of herbs (nettle, caraway, birch, celandine, marjoram, mint, peppermint, sage, St. John's wort, calamus, yarrow), used for production of medications, cosmetics and spices. It was found that processing of herbs was associated with a very high pollution of the air with bacteria, fungi, dust and endotoxin. The numbers of microorganisms (bacteria and fungi) in the air of herb processing plants ranged within 40.6-627.4 x 10(3) cfu/m3 (mean +/- S.D = 231.4 +/- 181.0 x 10(3) cfu/m3). The greatest concentrations were noted at the initial stages of production cycle, during cleaning, cutting and grinding of herbs. The numbers of airborne microorganisms were also significantly (p<0.0001) related to the kind of processed herb, being the greatest at processing marjoram, nettle, yarrow and mint. The values of the respirable fraction of airborne microflora in the examined facilities varied within a fairly wide range and were between 14.7-67.7%. The dominant microorganisms in the air of herb processing plants were mesophilic bacteria, among which endospore-forming bacilli (Bacillus spp.) and actinomycetes of the species Streptomyces albus were most numerous. Among Gram-negative bacteria, the most common was endotoxin-producing species Alcaligenes faecalis. Altogether, 37 species or genera of bacteria and 23 species or genera of fungi were identified in the air of herb processing plants, of these, 11 and 10 species or genera respectively were reported as having allergenic and/or immunotoxic properties. The concentrations of dust and bacterial endotoxin in the air of herb processing plants were large with extremely high levels at some sampling sites. The concentrations of airborne dust ranged within 3.2-946.0 mg/m3 (median 18.1 mg/m3), exceeding at 13 out of 14 sampling sites the Polish OEL value of 4 mg/m3. The concentrations of airborne endotoxin ranged within 0.2-2681.0 microg/m3 (median 16.0 microg/m3), exceeding at all sampling sites the suggested OEL value of 0.1 microg/m3. In conclusion, the workers of herb processing plants could be exposed to large concentrations of airborne microorganisms, dust and endotoxin posing a risk of work-related respiratory disease. PMID:11748878

Dutkiewicz, J; Krysi?ska-Traczyk, E; Skórska, C; Sitkowska, J; Prazmo, Z; Golec, M

2001-01-01

279

Workers' Exposure to Airborne Bacteria and Endotoxins at Industrial Wastewater Treatment Plants  

Microsoft Academic Search

A study of sewage workers' exposure to airborne culturable bacteria and inhaled endotoxins was performed at nine wastewater treatment plants that treat mainly industrial effluents. Airborne endotoxins were collected on glass fiber filters and analyzed using a chromogenic limulus assay. Endotoxin concentrations measured in the immediate vicinity of the wastewater treatment process varied from 0.1 to 350 ng\\/m. The eight-hour

Sirpa Laitinen; Juhani Kangas; Marjut Kotimaa; Jyrki Liesivuori; Pertti J. Martikainen; Aino Nevalainen; Riitta Sarantila; Kaj Husman

1994-01-01

280

Treatment Characteristics of Polysaccharides and Endotoxin Using Oxygen Plasma Produced by RF Discharge  

SciTech Connect

Treatment of polysaccharides and endotoxin were attempted using oxygen plasma produced by RF discharge. Oxygen radicals observed by optical light emission spectra are factors of decomposition of polysaccharides and endotoxin. Fourier transform infrared spectra indicate that most of chemical bonds in the polysaccharides are dissociated after irradiation of the oxygen plasma. Also, the decomposition rate of endotoxin was approximately 90% after irradiation of the oxygen plasma for 180 min.

Kitazaki, Satoshi; Hayashi, Nobuya [Faculty of Science and Engineering, Saga University, 1 Honjo-machi, Saga-shi, Saga, 840-8502 (Japan); Goto, Masaaki [Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga-shi, Saga, 849-8501 (Japan)

2010-10-13

281

Indoor Pollutant Exposures Modify the Effect of Airborne Endotoxin on Asthma in Urban Children  

PubMed Central

Rationale: The effect of endotoxin on asthma morbidity in urban populations is unclear. Objectives: To determine if indoor pollutant exposure modifies the relationships between indoor airborne endotoxin and asthma health and morbidity. Methods: One hundred forty-six children and adolescents with persistent asthma underwent repeated clinical assessments at 0, 3, 6, 9, and 12 months. Home visits were conducted at the same time points for assessment of airborne nicotine, endotoxin, and nitrogen dioxide (NO2) concentrations. The effect of concomitant pollutant exposure on relationships between endotoxin and asthma outcomes were examined in stratified analyses and statistical models with interaction terms. Measurements and Main Results: Both air nicotine and NO2 concentrations modified the relationships between airborne endotoxin and asthma outcomes. Among children living in homes with no detectable air nicotine, higher endotoxin was inversely associated with acute visits and oral corticosteroid bursts, whereas among those in homes with detectable air nicotine, endotoxin was positively associated with these outcomes (interaction P value = 0.004 and 0.07, respectively). Among children living in homes with lower NO2 concentrations (<20 ppb), higher endotoxin was positively associated with acute visits, whereas among those living in homes with higher NO2 concentrations, endotoxin was negatively associated with acute visit (interaction P value = 0.05). NO2 also modified the effect of endotoxin on asthma symptom outcomes in a similar manner. Conclusions: The effects of household airborne endotoxin exposure on asthma are modified by coexposure to air nicotine and NO2, and these pollutants have opposite effects on the relationships between endotoxin and asthma-related outcomes. PMID:24066676

Hansel, Nadia N.; Aloe, Charles; Schiltz, Allison M.; Peng, Roger D.; Rabinovitch, Nathan; Ong, Mary Jane; Williams, D’Ann L.; Breysse, Patrick N.; Diette, Gregory B.; Liu, Andrew H.

2013-01-01

282

Schistosomiasis japonica during pregnancy is associated with elevated endotoxin levels in maternal and placental compartments.  

PubMed

Schistosomiasis affects approximately 40 million women of reproductive age and has been linked to elevated levels of circulating endotoxin in nonpregnant individuals. We have evaluated endotoxin levels in maternal, placental, and newborn blood collected from women residing in Leyte, Philippines. Endotoxin levels in both maternal and placental compartments in pregnant women with schistosomiasis were 1.3- and 2.4-fold higher, respectively, than in uninfected women. In addition, higher concentrations of endotoxin in placental blood were associated with premature birth, acute chorioamnionitis, and elevated proinflammatory cytokines. By promoting endotoxemia, schistosomiasis may exert additional, maladaptive influences on pregnancy outcomes. PMID:23964108

McDonald, Emily A; Pond-Tor, Sunthorn; Jarilla, Blanca; Sagliba, Marianne J; Gonzal, Annaliza; Amoylen, Amabelle J; Olveda, Remigio; Acosta, Luz; Gundogan, Fusun; Ganley-Leal, Lisa M; Kurtis, Jonathan D; Friedman, Jennifer F

2014-02-01

283

Detection of bacterial endotoxin in drinking tap and bottled water in Kuwait.  

PubMed

This study was carried out to measure and compare the concentration of bacterial endotoxin in a variety of samples from drinking tap and bottled water available in Kuwait by using the Limulus Amoebocyte lysate test. A total of 29 samples were tested. Samples were collected from a variety of locations throughout the six governorates of Kuwait and 23 brands of local and imported bottled water samples were collected from the local market. The concentration of bacterial endotoxin was measured by using the standard Limulus Amoebocyte lysate test, gel clot method. This study showed that measured endotoxin concentrations in tap drinking water varied from 2.4 to 33.8 EU/ml with the average endotoxin concentration of 14.2 EU/ml. While the results of endotoxin concentrations in the bottled water were <0.03 to 20.1 EU/ml with an average of 1.96 EU/ml. The average concentration of endotoxin in bottled water is 13.5 % of the average concentration of endotoxin in tap drinking water. This experimental investigation has proved that drinking bottled water has less endotoxin as compared to tap water in Kuwait. It is also demonstrated that the endotoxin concentration did not exceed the acceptable level in drinking tap water. PMID:22270589

Abdulraheem, Abdulkareem; Mustafa, Seham; Al-Saffar, Nabeel; Shahjahan, Muhammed

2012-12-01

284

Molecular Characterization of Lipopolysaccharide Binding to Human ?-1-Acid Glycoprotein  

PubMed Central

The ability of AGP to bind circulating lipopolysaccharide (LPS) in plasma is believed to help reduce the proinflammatory effect of bacterial lipid A molecules. Here, for the first time we have characterized human AGP binding characteristics of the LPS from a number of pathogenic Gram-negative bacteria: Escherichia coli, Salmonella typhimurium, Klebsiella pneumonia, Pseudomonas aeruginosa, and Serratia marcescens. The binding affinity and structure activity relationships (SAR) of the AGP-LPS interactions were characterized by surface plasma resonance (SPR). In order to dissect the contribution of the lipid A, core oligosaccharide and O-antigen polysaccharide components of LPS, the AGP binding affinity of LPS from smooth strains, were compared to lipid A, Kdo2-lipid A, Ra, Rd, and Re rough LPS mutants. The SAR analysis enabled by the binding data suggested that, in addition to the important role played by the lipid A and core components of LPS, it is predominately the unique species- and strain-specific carbohydrate structure of the O-antigen polysaccharide that largely determines the binding affinity for AGP. Together, these data are consistent with the role of AGP in the binding and transport of LPS in plasma during acute-phase inflammatory responses to invading Gram-negative bacteria. PMID:23316371

Huang, Johnny X.; Azad, Mohammad A. K.; Yuriev, Elizabeth; Baker, Mark A.; Nation, Roger L.; Li, Jian; Cooper, Matthew A.; Velkov, Tony

2012-01-01

285

Detection of endotoxin in biological products by the limulus test.  

PubMed

The limulus amebocyte lysate (LAL) test is established as a beneficial quality assurance measure for the parenteral drug industry because of its sensitivity, specificity, and simplicity. Limulus amebocyte lysate reacts with various forms of endotoxin to form an opaque gel under acceptable conditions of pH, temperature, and ionic content. Although certain materials and conditions may alter the lysate-endotoxin reaction, the test is not significantly limited by inhibition or non-specific activation. Many U.S. drug firms apply the LAL test generally for monitoring production water and other ingredients, for an in-process control, and as a supplemental end product test for pyrogenic contamination. Specific applications are made for bacterial and viral vaccines, antineoplastic agents, radiopharmaceuticals and drugs designed for intrathecal injection. Efforts to standardize LAL test technique and lysate potency continue. PMID:838151

Cooper, J F; Pearson, S M

1977-01-01

286

A 15-week experimental exposure of pigs to airborne dust with added endotoxin in a continuous flow exposure chamber.  

PubMed Central

The purpose of this study was to evaluate the effect of longterm exposure to airborne dust and endotoxin on the respiratory system of pigs. A continuous flow exposure chamber was built for the purpose of exposing pigs to selected airborne contaminants. Pigs (n = 6) were exposed to a combination of a very fine corn/soybean meal (40.6 mg/m3) with added lipopolysaccharide (LPS; 12.4 microg/m3) for 8 h/d over 5 d for 15 wk (75 d of exposure). Control pigs (n = 6) were housed in a room with minimal contamination of these airborne contaminants. Surprisingly, dust in the exposure chamber and the control room was highly contaminated with peptidoglycan. Changes in the lung were monitored by collecting bronchoalveolar lavage (BAL) fluid for cytology at 5 different time points throughout the exposure period. Blood samples were collected at the same time for hematology. A non-specific respiratory inflammatory response was found in exposed and control pigs, as suggested by the increased neutrophils in BAL fluid and the small inflammatory areas in the lung tissue. No macroscopic lung lesions were observed in control or exposed pigs. The findings in the control pigs imply that even low dust concentrations and possibly peptidoglycan contamination can induce cellular changes in the BAL fluid and that a true control pig does not exist. In addition, the exposed pigs developed a mild eosinophilia, indicating an allergic response to the airborne contaminants. PMID:10369571

Jolie, R; Bäckström, L; Olson, L; Chase, C

1999-01-01

287

Endotoxin-induced basal respiration alterations of renal HK-2 cells: A sign of pathologic metabolism down-regulation  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer A HK-2 cells model of inflammation-induced acute kidney injury. Black-Right-Pointing-Pointer Two oximetry methods: high resolution respirometry and ESR spectroscopy. Black-Right-Pointing-Pointer Oxygen consumption rates of renal cells decrease when treated with LPS. Black-Right-Pointing-Pointer Cells do not recover normal respiration when the LPS treatment is removed. Black-Right-Pointing-Pointer This basal respiration alteration is a sign of pathologic metabolism down-regulation. -- Abstract: To study the mechanism of oxygen regulation in inflammation-induced acute kidney injury, we investigate the effects of a bacterial endotoxin (lipopolysaccharide, LPS) on the basal respiration of proximal tubular epithelial cells (HK-2) both by high-resolution respirometry and electron spin resonance spectroscopy. These two complementary methods have shown that HK-2 cells exhibit a decreased oxygen consumption rate when treated with LPS. Surprisingly, this cellular respiration alteration persists even after the stress factor was removed. We suggested that this irreversible decrease in renal oxygen consumption after LPS challenge is related to a pathologic metabolic down-regulation such as a lack of oxygen utilization by cells.

Quoilin, C., E-mail: cquoilin@ulg.ac.be [Laboratory of Biomedical Spectroscopy, Department of Physics, University of Liege, 4000 Liege (Belgium); Mouithys-Mickalad, A. [Center of Oxygen Research and Development, Department of Chemistry, University of Liege, 4000 Liege (Belgium)] [Center of Oxygen Research and Development, Department of Chemistry, University of Liege, 4000 Liege (Belgium); Duranteau, J. [Department of Anaesthesia and Surgical ICU, CHU Bicetre, University Paris XI Sud, 94275 Le Kremlin Bicetre (France)] [Department of Anaesthesia and Surgical ICU, CHU Bicetre, University Paris XI Sud, 94275 Le Kremlin Bicetre (France); Gallez, B. [Biomedical Magnetic Resonance Group, Louvain Drug Research Institute, Universite catholique de Louvain, 1200 Brussels (Belgium)] [Biomedical Magnetic Resonance Group, Louvain Drug Research Institute, Universite catholique de Louvain, 1200 Brussels (Belgium); Hoebeke, M. [Laboratory of Biomedical Spectroscopy, Department of Physics, University of Liege, 4000 Liege (Belgium)] [Laboratory of Biomedical Spectroscopy, Department of Physics, University of Liege, 4000 Liege (Belgium)

2012-06-29

288

Chemotactic Gradients Predict Neutrophilic Alveolitis in Endotoxin-treated Rats  

Microsoft Academic Search

We hypothesized that the intensity of neutrophilic alveolitis is related to establishing a gradient of neutrophil attractant chemokines across the alveolar-capillary barrier. In these experiments, a posi- tive chemokine gradient toward the alveoli was induced by intratracheal instillation of endotoxin in rats (IT LPS). Alteration of the chemotactic gradient was induced by combining IT LPS (0.1 mg\\/kg) with an intraperitoneal

TIMOTHY S. BLACKWELL; LISA H. LANCASTER; THOMAS R. BLACKWELL; ANNAPURNA VENKATAKRISHNAN; JOHN W. CHRISTMAN

1999-01-01

289

Engineered Corynebacterium glutamicum as an endotoxin-free platform strain for lactate-based polyester production.  

PubMed

The first biosynthetic system for lactate (LA)-based polyesters was previously created in recombinant Escherichia coli (Taguchi et al. 2008). Here, we have begun efforts to upgrade the prototype polymer production system to a practical stage by using metabolically engineered Gram-positive bacterium Corynebacterium glutamicum as an endotoxin-free platform. We designed metabolic pathways in C. glutamicum to generate monomer substrates, lactyl-CoA (LA-CoA), and 3-hydroxybutyryl-CoA (3HB-CoA), for the copolymerization catalyzed by the LA-polymerizing enzyme (LPE). LA-CoA was synthesized by D: -lactate dehydrogenase and propionyl-CoA transferase, while 3HB-CoA was supplied by ?-ketothiolase (PhaA) and NADPH-dependent acetoacetyl-CoA reductase (PhaB). The functional expression of these enzymes led to a production of P(LA-co-3HB) with high LA fractions (96.8 mol%). The omission of PhaA and PhaB from this pathway led to a further increase in LA fraction up to 99.3 mol%. The newly engineered C. glutamicum potentially serves as a food-grade and biomedically applicable platform for the production of poly(lactic acid)-like polyester. PMID:22127753

Song, Yuyang; Matsumoto, Ken'ichiro; Yamada, Miwa; Gohda, Aoi; Brigham, Christopher J; Sinskey, Anthony J; Taguchi, Seiichi

2012-03-01

290

Molecular and Cellular Regulation of Toll-Like Receptor-4 Activity Induced by Lipopolysaccharide Ligands  

PubMed Central

As well as being the primary signaling receptor for bacterial endotoxin or lipopolysaccharide Toll-like receptor-4 function is modulated by numerous factors not only in the context of microbial pathogenesis but also autoimmune and allergic diseases. TLR4 is subject to multiple levels of endogenous control and regulation from biosynthesis and trafficking to signal transduction and degradation. On the other hand regulation of TLR4 activity breaks down during Gram ?ve sepsis leading to systemic damage, multi organ failure, and death. In this article, we review how TLR4 traffics from the early secretory pathway, the cis/trans Golgi to the cell surface and endolysosomal compartments. We will present evidence about how these processes influence signaling and can potentially lead to increased sensitivity to ligand-dependent activation as well as ligand-independent constitutive activation that may contribute to pathogenesis in sepsis. We will also discuss how sustained signaling may be coupled to endocytosis and consider the potential molecular mechanisms of immuno-modulators that modify TLR4 signaling function including the cat allergen FelD1 and endogenous protein ligands such as the extracellular matrix protein tenascin C and calprotectin (MRP8/14). PMID:25339952

Liaunardy-Jopeace, Ardiyanto; Gay, Nicholas J.

2014-01-01

291

Effects of caffeic acid phenethyl ester on lipopolysaccharide-induced lung injury in rats.  

PubMed

Extracts of propolis, a natural beehive product, have been known for centuries to have a variety of beneficial medical properties, among which their anti-inflammatory effect is a major one. Caffeic acid phenethyl ester (CAPE), an active propolis component, has antimicrobial, anti-inflammatory, antioxidant, carcinostatic and immunomodulatory properties. In this study, we aimed to investigate the efficacy of CAPE in endotoxin-induced lung injury in rats. Lung injury was induced by a footpad injection of lipopolysaccharide (LPS). In the treatment group, 10 micromol kg(-1) CAPE was injected intraperitoneally immediately after LPS injection. At 24 h after LPS and/or CAPE injection, blood and lung tissue specimens were collected. MDA levels and MPO activity in serum and lung tissue, serum total antioxidant levels, lung tissue Na(+)/K(+) ATP-ase activity and histopathological evaluation were determined to assess the efficacy of CAPE treatment. CAPE was found to be efficient in reducing inflammation and lung tissue damage induced by LPS in rats. PMID:15953745

Koksel, Oguz; Ozdulger, Ali; Tamer, Lulufer; Cinel, Leyla; Ercil, Menderes; Degirmenci, Ulas; Unlu, Serdar; Kanik, Arzu

2006-01-01

292

Bound To Shock: Protection from Lethal Endotoxemic Shock by a Novel, Nontoxic, Alkylpolyamine Lipopolysaccharide Sequestrant?  

PubMed Central

Lipopolysaccharide (LPS), or endotoxin, a structural component of gram-negative bacterial outer membranes, plays a key role in the pathogenesis of septic shock, a syndrome of severe systemic inflammation which leads to multiple-system organ failure. Despite advances in antimicrobial chemotherapy, sepsis continues to be the commonest cause of death in the critically ill patient. This is attributable to the lack of therapeutic options that aim at limiting the exposure to the toxin and the prevention of subsequent downstream inflammatory processes. Polymyxin B (PMB), a peptide antibiotic, is a prototype small molecule that binds and neutralizes LPS toxicity. However, the antibiotic is too toxic for systemic use as an LPS sequestrant. Based on a nuclear magnetic resonance-derived model of polymyxin B-LPS complex, we had earlier identified the pharmacophore necessary for optimal recognition and neutralization of the toxin. Iterative cycles of pharmacophore-based ligand design and evaluation have yielded a synthetically easily accessible N1,mono-alkyl-mono-homologated spermine derivative, DS-96. We have found that DS-96 binds LPS and neutralizes its toxicity with a potency indistinguishable from that of PMB in a wide range of in vitro assays, affords complete protection in a murine model of LPS-induced lethality, and is apparently nontoxic in vertebrate animal models. PMID:17548488

Sil, Diptesh; Shrestha, Anurupa; Kimbrell, Matthew R.; Nguyen, Thuan B.; Adisechan, Ashok K.; Balakrishna, Rajalakshmi; Abbo, Benjamin G.; Malladi, Subbalakshmi; Miller, Kelly A.; Short, Shannon; Cromer, Jens R.; Arora, Shravan; Datta, Apurba; David, Sunil A.

2007-01-01

293

Lipopolysaccharide and Soluble CD14 in Cord Blood Plasma are associated with Prematurity and Chorioamnionitis  

PubMed Central

Background Lipopolysaccharide (LPS), an endotoxin of gram-negative bacteria, causes preterm birth in animals and has been implicated as a factor triggering preterm labor and systemic complications in humans. Little is known regarding LPS in the cord blood (CB) of term and preterm infants and its association with maternal and fetal characteristics. Methods CB was obtained from term (n=15) and preterm infants (n=76) after delivery. Plasma levels of LPS, C-Reactive Protein (CRP) and soluble CD14 (sCD14) were measured using commercially available kits (Limulus Amebocyte Lysate (LAL) assay and ELISA). Four linear regression models were created in order to identify independent variables that predict plasma LPS levels. Results CB LPS (24.48 vs. 1 pg/ml), CRP (87.9 vs. 47 ng/ml) and sCD14 (0.32 vs.0.35 µg/ml) levels were significantly higher in the preterm than the term infants. CB LPS levels correlate with gestational age, birth weight, CRP levels, sCD14 levels and the presence of both clinical and histological chorioamnionitis. Conclusion Our data suggest that LPS is associated with preterm labor and inflammation (CRP elevation and chorioamnionitis). These findings may be relevant to understand the role of LPS in prematurity and its possible role in preterm morbidities. PMID:24135785

Martinez, Denise G.; Funderburg, Nicholas T.; Cerissi, Adam; Rifaie, Reema; Aviles-Medina, Laura; Llorens-Bonilla, Braulio J.; Sleasman, John; Luciano, Angel A.

2014-01-01

294

Cordyceps sinensis prevents apoptosis in mouse liver with D-galactosamine/lipopolysaccharide-induced fulminant hepatic failure.  

PubMed

Cordyceps sinensis (C. sinensis) has long been considered to be an herbal medicine and has been used in the treatment of various inflammatory diseases. The present study examined the cytoprotective properties of C. sinensis on D(+)-galactosamine (GalN)/lipopolysaccharide (LPS)-induced fulminant hepatic failure. Mice were randomly assigned into control, GalN/LPS, CS 20 mg and CS 40 mg groups (C. sinensis, oral gavage, five days/week, four weeks). After receiving saline or C. sinensis, mice were intraperitoneally given GalN (800 mg/kg)/LPS (10 ?g/kg). The effects of C. sinensis on TNF-?, IL-10, AST, NO, SOD, and apoptoticrelated proteins after the onset of endotoxin intoxication were determined. Data demonstrated that GalN/LPS increased hepatocyte degeneration, circulating AST, TNF-?, IL-10, and hepatic apoptosis and caspase activity. C. sinensis pre-treatment reduced AST, TNF-?, and NO and increased IL-10 and SOD in GalN/LPS induced fulminant hepatic failure. C. sinensis attenuated the apoptosis of hepatocytes, as evidenced by the TUNEL and capase-3, 6 activity analyses. In summary, C. sinensis alleviates GalN/LPS-induced liver injury by modulating the cytokine response and inhibiting apoptosis. PMID:24707872

Cheng, Yu-Jung; Cheng, Shiu-Min; Teng, Yi-Hsien; Shyu, Woei-Cherng; Chen, Hsiu-Ling; Lee, Shin-Da

2014-01-01

295

Lipopolysaccharides accelerate hepatic steatosis in the development of nonalcoholic fatty liver disease in Zucker rats.  

PubMed

Nonalcoholic fatty liver disease (NAFLD) can develop into end-stage disease that includes cryptogenic cirrhosis and hepatocellular carcinoma. Bacterial endotoxin, for example lipopolysaccharide (LPS), plays an important role in the pathogenesis of NAFLD. The aim of this study was to assess the role of LPS in the development of NAFLD. Twenty-one male Zucker (fa/fa) rats were divided into three groups: rats fed for twelve weeks on a diet rich in disaccharide (D12 group), rats similarly managed but treated with LPS (LPS group), and those on the same diet for 24 weeks (D24 group). Histological examination demonstrated that this protocol induced hepatic steatosis in the LPS and D24 groups. Significant, marked accumulation of lipid droplets was observed in the LPS group, compared with the D24 group. Rats from the LPS group showed a decrease in plasma adiponectin levels, an increase in plasma leptin levels, and greater expression of FAS and SREBP-1c mRNA in the liver, compared with rats from the D24 group. These finding coincided with histological findings. We therefore suggest that LPS may accelerate the progression of hepatic steatosis. PMID:24426189

Fukunishi, Shinya; Sujishi, Tetsuya; Takeshita, Atsushi; Ohama, Hideko; Tsuchimoto, Yusuke; Asai, Akira; Tsuda, Yasuhiro; Higuchi, Kazuhide

2014-01-01

296

Evolution of endotoxin induced acute lung injury in the rat.  

PubMed

To clarify the evolution of acute lung injury induced by endotoxin, the progression of lung damage in 26 rats submitted to intratracheal instillation of 5 mg/kg body weight endotoxin was examined by blood gas analysis, computerized tomography, light and electron microscopy. Hypoxaemia, hypercapnia, acidosis and inhomogeneous bilateral infiltrates developed gradually within 48 hours. Monocytes appeared within blood capillaries and the instertitium by 12 hours after treatment, then migrated into alveoli and underwent progressive differentiation into macrophages by 24 hours after treatment. Granulocytes were found within blood capillaries at an early stage, but outside capillaries only at 48 hours. Hyperplasia of type II pneumocytes and hypertrophy of interstitial fibroblasts also occurred at 48 hours. These data suggest that the pathogenesis of endotoxin induced pulmonary injury proceeds through an early phase of granulocyte migration inside capillaries and monocyte extravasation, an intermediate phase of monocyte differentiation into macrophages inside alveoli and a late phase of diffuse infiltration of alveoli by newly differentiated macrophages and late-extravasated neutrophils. PMID:7488552

Domenici-Lombardo, L; Adembri, C; Consalvo, M; Forzini, R; Meucci, M; Romagnoli, P; Novelli, G P

1995-10-01

297

Airborne Endotoxin from Indoor and Outdoor Environments:Effect of Sample Dilution on the Kinetic Limulus Amebocyte Lysate (LAL) Assay  

Technology Transfer Automated Retrieval System (TEKTRAN)

Airborne endotoxin in occupational environments are a potential respiratory hazard to individuals. In this study, total and inhalable airborne endotoxin samples were collected via filtration from inside animal housing units and downwind from agricultural production sites and a wastewater treatment ...

298

Cell signaling and cytokine induction by lipopolysaccharide  

Microsoft Academic Search

\\u000a Multicellular organisms have evolved molecular systems to recognize the structural hallmarks of pathogens and an arsenal of\\u000a responses to contain and ultimately eliminate invaders. Lipopolysaccharide (LPS) derived from the cell walls of Gram-negative\\u000a bacteria is an important initiator of such “innate” immune responses. This recognition normally leads to a robust local immune\\u000a response to invading bacteria which is protective; however,

Mary Lee MacKichan; Anthony L. DeFranco

299

Tolerance to Lipopolysaccharide in Human Blood Monocytes  

Microsoft Academic Search

When monocytes are stimulated with Lipopolysaccharide (LPS), they efficiently produce cytokines like tumor necrosis factor (TNF). Upon secondary stimulation, this response is only minimal, and there is little TNF mRNA transcription, mRNA accumulation, and protein production. Studies with the monocytic cell line Mono Mac 6 have shown that in such tolerant cells the CD14 LPS receptor is still present, and

H. W. Löms Ziegler-Heitbrock; Marion Frankenberger; Angela Wedel

1995-01-01

300

Intravenous endotoxin triggers pulmonary vasoconstriction and pulmonary hypertension in broiler chickens.  

PubMed

Bacterial endotoxins stimulate endothelin-mediated, thromboxane-dependent increases in pulmonary vascular resistance in mammals, and thromboxane has been shown to cause an immediate but transient pulmonary vasoconstriction in broiler chickens. In the present study, i.v. injections of 1 mg endotoxin into anesthetized male broilers caused a pulmonary vasoconstrictive response that was delayed in onset by 15 min and that elevated the pulmonary arterial pressure by 10 mm Hg within 25 min postinjection. Thereafter, pulmonary hemodynamic variables gradually (> or = 15 min) returned toward pre-injection levels, and supplemental injections of 4 mg endotoxin during this recovery period failed to reinitiate pulmonary hypertension. In contrast, injecting the thromboxane A2 mimetic U44069 during the endotoxin recovery period triggered pulmonary vasoconstriction and pulmonary hypertension similar in magnitude to the responses triggered by U44069 before endotoxin had been administered. The time course and magnitude of the pulmonary hemodynamic responses to endotoxin were highly variable among individual broilers, whereas the individual responses to U44069 were more consistent. Unanesthetized broilers resembled anesthetized broilers in the time course, magnitude, and variability of their pulmonary hemodynamic responses to endotoxin. Overall, these observations are consistent with the hypothesis that endotoxin initiates a biochemical cascade, culminating in the delayed onset of pulmonary vasoconstriction and pulmonary hypertension within 20 min postinjection. Subsequently, the pulmonary vasculature remains responsive to large bolus injections of exogenous thromboxane mimetic; however depletion of endogenous vasoconstrictive components of the endotoxin-mediated cascade, a compensatory increase in endogenous vasodilators, or the induction of a transient cellular tolerance to endotoxin prevented fourfold higher doses of endotoxin from reversing the return toward a normal pulmonary vascular tone. Individual differences among broilers in their susceptibility to pulmonary hypertension syndrome (ascites) may be related to innate or acquired variability in their pulmonary vascular responsiveness to vasoactive mediators. PMID:11372717

Wideman, R F; Erf, G F; Chapman, M E

2001-05-01

301

Exposure to wood dust and endotoxin in small-scale wood industries in Tanzania.  

PubMed

Workers in small-scale wood industries (SSWI) have increased risks of developing asthma and other respiratory diseases. Wood dust and microbial agents have both been suggested to play a role, but few studies have measured endotoxin exposure in SSWI in Africa. We assessed inhalable dust levels in 281 samples from 115 workers and bacterial endotoxins levels in 157 samples from 136 workers from SSWI in Dar es Salaam, Tanzania. The overall geometric mean of personal exposure was 3.3 mg/m(3); geometric standard deviation (GSD) 2.5; range 0.45-67.0 mg/m(3)) and 91 EU/m(3) (GSD 3.7; range 9-4914.8 EU/m(3)) for wood dust and endotoxins, respectively. Dust and endotoxin levels were weakly correlated (r = 0.44, n = 157, P < 0.0001). Between- and within-worker variances and percentages explained by the differences among job titles and seasons were 0.31 (9%) and 0.35 (30%), respectively, for wood dust exposure, and 0.35 (0%) and 0.35 (38%) for endotoxin exposure. Higher dust and endotoxin exposure levels were observed in the dry compared to the wet season, after correcting for differences in exposure between jobs. Carving and manual cleaning were associated with the highest dust exposures. Sewing seat covers and manual cleaning were associated with the highest endotoxin exposures. Dust and endotoxin exposure levels in SSWI are high and appropriate control measures are necessary. PMID:15114366

Rongo, Larama Mb; Msamanga, Gernard I; Burstyn, Igor; Barten, Françoise; Dolmans, Wil Mv; Heederik, Dick

2004-11-01

302

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

E-print Network

Expression of a Bacillus thuringiensis d-endotoxin gene by Bacillus pumilus L.B. Selinger, G.G. Khachatourians, J.R. Byers, and M.F. Hynes Abstract: The -endotoxin genes from Bacillus thuringiensis were orthogonia Morrison (Lepidoptera: Noctuidae)). Preliminary experiments indicated that Bacillus thuringiensis

Selinger, Brent

303

Are Cats and Dogs the Major Source of Endotoxin in Homes?  

PubMed Central

Previous studies have suggested that exposure to cats and dogs during early childhood reduces the risk of allergic disease, possibly by increasing home endotoxin exposure. This study asked the question of whether cats and dogs are the dominant influence on dust endotoxin concentrations in homes after considering other variables reportedly associated with endotoxin. The presence of cats or dogs in homes, household and home characteristics, and dust endotoxin concentrations from 5 locations were assessed in 966 urban and suburban homes. Whether considered together as pets or as cats and dogs separately, the presence of cats and dogs significantly contributed to living room and bedroom floor endotoxin concentrations but not to bed endotoxin concentrations. However, the two variables consistently related to endotoxin in all home sites were the home occupant density (occupants/room) and cleanliness of the home. Our data suggests that reducing occupant density and improving home cleanliness would reduce home endotoxin concentrations more than removing pet cats or dogs from the home. PMID:23167871

Ownby, Dennis R.; Peterson, Edward L.; Wegienka, Ganesa; Woodcroft, Kimberley J.; Nicholas, Charlotte; Zoratti, Edward; Johnson, Christine C.

2014-01-01

304

MICROWAVE RADIATION (2450 MHZ) ALTERS THE ENDOTOXIN-INDUCED HYPOTHERMIC RESPONSE OF RATS  

EPA Science Inventory

The parental administration of bacterial endotoxin to rats causes a hypothermia that is maximal after approximately 90 minutes. When endotoxin-injected rats were held in a controlled environment at 22C and 50% relative humidity and exposed for 90 minutes to microwaves (2450 MHz, ...

305

Exposure to endotoxin decreases the risk of atopic eczema in infancy: A cohort study  

Microsoft Academic Search

Background: Previous studies have shown a protective effect of early exposure to cats and dogs on the development of atopic eczema, asthma, allergic rhinitis, and atopic sensitization in later life. In particular, a higher microbial exposure to endotoxin in early childhood might contribute to this effect. Objective: We examined the associations between bacterial endotoxin in house dust and atopic eczema,

Ulrike Gehring; Gabriele Bolte; Michael Borte; Wolfgang Bischof; Bärbel Fahlbusch; H.-Erich Wichmann; Joachim Heinrich

2001-01-01

306

Quantitative Limulus lysate assay for endotoxin and the effect of plasma  

Microsoft Academic Search

The effects of plasma and chromogenic substrate on the kinetics of the endotoxin-activated Limulus amoebocyte lysate (LAL) assay were determined. A linear correlation was observed between the rate of development of turbidity (optical density 405) with the LAL reagent and the concentration of endotoxin over a four log ten-fold range. Like chromogenic substrate, the addition of dilution and heat treated

J C Hurley; F A Tosolini; W J Louis

1991-01-01

307

House Dust Endotoxin and Wheeze in the First Year of Life  

Microsoft Academic Search

We examined endotoxin exposure and wheezing episodes during the first year of life in a birth cohort of 499 infants with one or both parents having a history of asthma or allergy. We measured endotoxin in settled dust from the baby's bed, bedroom floor, family room, and kitchen floor within the first 3 mo after birth. The primary outcomes were

JU-HYEONG PARK; DIANE R. GOLD; DONNA L. SPIEGELMAN; HARRIET A. BURGE; DONALD K. MILTON

2001-01-01

308

Assessment of Airborne Exposure to Endotoxin and Pyrogenic Active Dust Using Electrostatic Dustfall Collectors (EDCs)  

Microsoft Academic Search

Passive airborne dust sampling using electrostatic dustfall collectors (EDCs) is one possibility especially for long sampling periods. In this study, EDCs were deposited in living rooms of private households and in social rooms of composting plants. The aim of the study was to determine whether endotoxin and pyrogenic activity are measurable using EDCs. In all extracts, endotoxin (via Limulus amebocyte

Verena Liebers; Vera van Kampen; Jürgen Bünger; Maria Düser; Heike Stubel; Thomas Brüning; Monika Raulf-Heimsoth

2012-01-01

309

Dexamethasone inhibits endotoxin-induced changes in calcium and contractility in rat isolated papillary muscle.  

PubMed

This study investigates whether endotoxin-induced contractile dysfunction is associated with a defect in the modulation of calcium homeostasis and the potential mechanisms involved. Treatment of rats in vivo with endotoxin significantly decreased the magnitude of contractile transients in electrically stimulated left ventricular papillary muscle isolated after an equilibration period of 6 hours. Although no significant difference was found in the peak intracellular calcium concentration ([Ca2+]i) between the endotoxin-treated and control groups, resting [Ca2+]i) was significantly elevated in the endotoxin-treated group, producing a smaller Ca2+ transient (basal-peak difference) in this group. Pretreatment of rats with dexamethasone prevented the endotoxin-induced decrease in peak tension and inhibited the elevation in resting [Ca2+]i, with a resultant maintenance of Ca2+ transient magnitude. Similar observations were made during stimulation of the muscles by the beta-adrenoceptor agonist, isoprenaline. These results show that endotoxin-induced reduction of cardiac contractile performance is mediated, at least in part, by elevating resting [Ca2+]i, and a glucocorticoid protected from these negative effects. While endotoxin reduces the magnitude of the Ca2+ transient it does not alter peak [Ca2+]i availability. Further investigation is required to determine whether endotoxin decreases contractile performance by reducing the sensitivity of cardiac myofilaments to calcium. PMID:10892565

Reilly, A M; Sun, X; Williams, D A; Dusting, G J

1999-01-01

310

A new method for concentration analysis of bacterial endotoxins in perfluorocarbon  

NASA Astrophysics Data System (ADS)

This communication demonstrates the feasibility of the gel-clot method for the analysis of bacterial endotoxins in water extracts of perfluorocarbon which is a water insoluble liquid medical device. Perfluorocarbon (10 mL) was shaken with 10mL water for 15 min at 2000 r/min and the endotoxin present was extracted to the aqueous phase without interference inhibition/enhancement of the product and the recovery of endotoxin added to perfluorocarbon was determined. A validation study confirmed that endotoxins presented in perfluorocarbon pass over into the aqueous phase at concentrations of 20, 10 and 5 EU/mL with recoveries from 86.8% to 96.8%. Therefore, the gel-clot test is suitable for detecting bacterial endotoxins in perfluorocarbon which is a water insoluble medical device.

Chen, Dan-Dan; Feng, Xiao-Ming; Wang, Chun-Ren; Huang, Qing-Quan; Yang, Zhao-Peng; Meng, Qing-Yuan

2014-12-01

311

Endotoxin in blood and tissue in the sudden infant death syndrome.  

PubMed

Although the explanation for sudden infant death syndrome (SIDS) remains unknown, an increasing body of evidence now exists to suggest a possible role for bacterial toxins in the aetiology, and a number of investigators have considered that endotoxaemia could explain some of the associated features. Following the development of an animal model which confirmed that endotoxaemia could be detected after death, we studied endotoxin levels in blood and tissue samples taken at autopsy from SIDS infants, child controls and adult controls. There were significant correlations between endotoxin levels in blood and the various organs sampled particularly in SIDS cases and child controls, and blood endotoxin levels in SIDS cases were higher in those infants where there was histological evidence of mild to moderate inflammation. However, overall no significant differences were found between endotoxin levels in blood or tissue in the three study groups. Further studies into possible actions or interactions of endotoxin in SIDS are required. PMID:10443501

Crawley, B A; Morris, J A; Drucker, D B; Barson, A J; Morris, J; Knox, W F; Oppenheim, B A

1999-08-01

312

p38 Mitogen-Activated Protein Kinase Mediates Lipopolysaccharide and Tumor Necrosis Factor Alpha Induction of Shiga Toxin 2 Sensitivity in Human Umbilical Vein Endothelial Cells  

Microsoft Academic Search

Escherichia coli O157:H7 Shiga toxin 2 (Stx2), one of the causative agents of hemolytic-uremic syndrome, is toxic to endothelial cells, including primary cultured human umbilical vein endothelial cells (HUVEC). This sensitivity of cells to Stx2 can be increased with either lipopolysaccharide (LPS) or tumor necrosis factor alpha (TNF-). The goal of the present study was to identify the intracellular signaling

Matthew K. Stone; Glynis L. Kolling; Matthew H. Lindner; Tom G. Obrig

2008-01-01

313

Alcohol, Intestinal Bacterial Growth, Intestinal Permeability to Endotoxin, and Medical Consequences  

PubMed Central

This report is a summary of the symposium on Alcohol, Intestinal Bacterial Growth, Intestinal Permeability to Endotoxin, and Medical Consequences, organized by National Institute on Alcohol Abuse and Alcoholism, Office of Dietary Supplements, and National Institute of Diabetes and Digestive and Kidney Diseases of National Institutes of Health in Rockville, Maryland, October 11, 2006. Alcohol exposure can promote the growth of Gram negative bacteria in the intestine which may result in accumulation of endotoxin. In addition, alcohol metabolism by Gram negative bacteria and intestinal epithelial cells can result in accumulation of acetaldehyde, which in turn can increase intestinal permeability to endotoxin by increasing tyrosine phosphorylation of tight junction and adherens junction proteins. Alcohol-induced generation of nitric oxide may also contribute to increased permeability to endotoxin by reacting with tubulin, which may cause damage to microtubule cytoskeleton and subsequent disruption of intestinal barrier function. Increased intestinal permeability can lead to increased transfer of endotoxin from the intestine to the liver and general circulation where endotoxin may trigger inflammatory changes in the liver and other organs. Alcohol may also increase intestinal permeability to peptidoglycan which can initiate inflammatory response in liver and other organs. In addition, acute alcohol exposure may potentiate the effect of burn injury on intestinal bacterial growth and permeability. Decreasing the number of Gram negative bacteria in the intestine can result in decreased production of endotoxin as well as acetaldehyde which is expected to decrease intestinal permeability to endotoxin. In addition, intestinal permeability may be preserved by administering epidermal growth factor, L-glutamine, oats supplementation, or zinc thereby preventing the transfer of endotoxin to the general circulation. Thus reducing the number of intestinal Gram negative bacteria and preserving intestinal permeability to endotoxin may attenuate alcoholic liver and other organ injuries. PMID:18504085

Purohit, Vishnudutt; Bode, J. Christian; Bode, Christiane; Brenner, David A.; Choudhry, Mashkoor A.; Hamilton, Frank; Kang, Y. James; Keshavarzian, Ali; Rao, Radhakrishna; Sartor, R. Balfour; Swanson, Christine; Turner, Jerrold R.

2008-01-01

314

Dose-dependent pulmonary effects of inhaled endotoxin in guinea pigs.  

PubMed

As a cell wall component of gram-negative bacteria, endotoxin is thought to play a significant role in the respiratory effects of inhaled organic dusts which are microbially contaminated. Assessment of occupational survey data and clinical studies suggests that few measureable, acute functional changes occur below 30-50 ng/m3 endotoxin (as sampled in airborne dust with a vertical elutriator). Little information is available on the inflammatory effects of inhaled endotoxin at these low concentrations. The present study examined the dose-response relationship between inhaled endotoxin and functional, biochemical, and histological endpoints in the lungs of guinea pigs. Animals were exposed to 0.03 to 50.5 micrograms/m3 aerosolized endotoxin or the vehicle water for 4 hr. At 2 hr into exposure, significant decreases in specific airway conductance were observed only in animals exposed to 9.6 and 50.5 micrograms/m3 endotoxin (17.3 +/- 1.2 and 35.5 +/- 0.5% decreases from baseline values, respectively (mean +/- SE)). Total cell count and lactate dehydrogenase levels in bronchoalveolar lavage fluid were significantly elevated at 24 hr after exposure in all endotoxin-exposed groups except the lowest dose, 0.03 micrograms/m3 (P < 0.05). Polymorphonuclear leukocyte influx into the alveolar region was also dependent on the concentration of inhaled endotoxin. Thus, LDH activity, a biochemical marker of cell injury, and total cell counts and polymorphonuclear leukocytes, markers of inflammation, were more sensitive indices of adverse pulmonary effects from inhaled endotoxin than a functional measurement. These results suggest that subtle inflammatory changes may occur at airborne endotoxin concentrations which may produce no acute respiratory symptoms. PMID:1464292

Gordon, T

1992-12-01

315

Exposure to dust and endotoxin of employees in cucumber and tomato nurseries.  

PubMed

Exposure to bioaerosols in occupational settings is associated with a range of adverse health effects. The aim of this study was to investigate the exposure levels to dust and endotoxin of people working in two cucumber nurseries and two tomato nurseries. Exposure was measured for greenhouse workers (n = 70) mainly working on harvesting cucumbers and tomatoes and clearing the plants after the harvest season. The people were exposed to between 0.2 and 15 mg inhalable dust m(-3) (median = 1.6 mg m(-3)) and between 0.5 and 400 ng inhalable endotoxin m(-3) (median = 32 ng m(-3)). The exposure to 'total dust' and endotoxin measured by stationary samplers (n = 30) in the greenhouses was low. Endotoxin was present in relatively high concentrations on cucumber leaves compared with leaves on pot plants. The Danish occupational exposure limit (OEL) for total organic dust is 3 mg m(-3) and 36% and 17% of the cucumber and tomato workers, respectively, were exposed to >3.0 mg inhalable dust m(-3). There is no OEL for endotoxin, but 'no effect levels' at approximately 15 ng m(-3) have been found. The majority of subjects (65%) were exposed to >15 ng m(-3). Significantly higher exposure was found for employees in cucumber nurseries than for employees in tomato nurseries. Clearing tomato plants after the harvest season caused a higher exposure to endotoxin than tomato harvesting. In conclusion, people working in cucumber and tomato nurseries were often exposed to high levels of inhalable dust and endotoxin. Cucumber harvest workers were exposed to significantly more dust and endotoxin than tomato harvest workers. The dust and endotoxin aerosolized during the working processes were only transported to other areas in the greenhouses to a very low degree. Cucumber and tomato leaves were identified as endotoxin reservoirs. PMID:19033558

Madsen, A M; Hansen, V M; Nielsen, S H; Olsen, T T

2009-03-01

316

Aggregation Behavior of an Ultra-Pure Lipopolysaccharide that Stimulates TLR-4 Receptors  

E-print Network

by lipopolysaccharides (LPS), which are glucosamine-based phospholipids that form the outer leaflet of the outer pathways, respectively. INTRODUCTION Lipopolysaccharide (LPS) is an amphiphilic glucosamine- based

White, Stephen

317

Damage of lipopolysaccharides in outer cell membrane and production of ROS-mediated stress within bacteria makes nano zinc oxide a bactericidal agent  

NASA Astrophysics Data System (ADS)

Zinc oxide nanoparticle (ZNP) has been synthesized by microwave-assisted technique with the aid of a buffer solution. ZNP inhibited the growth of bacterial system Escherichia coli, even its multidrug-resistant counterpart as well. Systematic evaluation reveals that bioavailable crystalline ZNP damages the lipopolysaccharide layer from outer membrane (OM) of E. coli, subsequently damages the OM followed by inner membrane, enters within the cell and generates extensive reactive oxygen species-mediated damage. A series of biochemical, biophysical and molecular techniques have been used to reach the conclusion. We believe this work is expected to enlighten the detailed mode of action study in bacterial system.

Patra, Prasun; Roy, Shuvrodeb; Sarkar, Sampad; Mitra, Shouvik; Pradhan, Saheli; Debnath, Nitai; Goswami, Arunava

2014-12-01

318

Neonatal Programming by Neuroimmune Challenge: Effects on Responses and Tolerance to Septic Doses of Lipopolysaccharide in Adult Male and Female Rats  

PubMed Central

A mild immune challenge experienced during the neonatal period leads to attenuated febrile responses to a similar challenge experienced later in life. However, the immune response to an endotoxin differs depending upon the severity of the challenge and it is not clear whether a neonatal immune challenge will also affect responses to a severe, potentially life-threatening stimulus, such as sepsis. In the present study, we examined the effects of a neonatal immune challenge with lipopolysaccharide (LPS) on adult sickness responses, as well as the development of endotoxin tolerance, to a septic dose (1 or 3 mg/kg) of the same LPS in male and female rats. We demonstrate significant differences, particularly in males, in the fever profiles of neonatally LPS-treated rats compared to neonatally saline-treated controls. Specifically, male rats treated neonatally with LPS have reduced hypothermic and enhanced hyperthermic responses to both septic doses of LPS in adulthood. A somewhat different profile is seen in females, with neonatally LPS-treated females having reduced hypothermia and enhanced hyperthermia compared to controls with 1 mg/kg but no differences with 3 mg/kg LPS. The results obtained demonstrate that alterations in innate immune responses previously reported for low doses of LPS can, for the most part, also be observed after severe immune challenge in later life. PMID:20136690

Spencer, S. J.; Field, E.; Pittman, Q. J.

2012-01-01

319

[Yersinia lipopolysaccharide and its biological activity].  

PubMed

The data on the structure and biological activity of the lipopolysaccharide (LPS) of Yersinia as an important virulence factor are analyzed. The biological effects of LPS are characterized by dose dependence: small doses stimulate the intensity of phagocytosis, while large doses decrease phagocytic activity and produce cytotoxic effect. Yersinia LPS plays an important role in the development of such consequences of yersiniosis as reactive arthritis, erythema nodosum, Reiter's syndrome. Yersinia LPS is a widespread component for the diagnostics of yersiniosis and pseudotuberculosis. PMID:16830602

Svarval', A V; Tseneva, G Ia; Shenderovich, O A

2006-01-01

320

VIP Deficient Mice Exhibit Resistance to Lipopolysaccharide Induced Endotoxemia with an Intrinsic Defect in Proinflammatory Cellular Responses  

PubMed Central

Vasoactive intestinal peptide (VIP) is a pleiotropic neuropeptide with immunomodulatory properties. The administration of this peptide has been shown to have beneficial effects in murine models of inflammatory diseases including septic shock, rheumatoid arthritis, multiple sclerosis (MS) and Crohn's disease. However, the role of the endogenous peptide in inflammatory disease remains obscure because VIP-deficient mice were recently found to exhibit profound resistance in a model of MS. In the present study, we analyzed the response of female VIP deficient (KO) mice to intraperitoneal lipopolysaccharide (LPS) administration. We observed significant resistance to LPS in VIP KO mice, as evidenced by lower mortality and reduced tissue damage. The increased survival was associated with decreased levels of proinflammatory cytokines (TNF?, IL-6 and IL-12) in sera and peritoneal suspensions of these mice. Moreover, the expression of TNF? and IL-6 mRNA was reduced in peritoneal cells, spleens and lungs from LPS-treated VIP KO vs. WT mice, suggesting that the resistance might be mediated by an intrinsic defect in the responsiveness of immune cells to endotoxin. In agreement with this hypothesis, peritoneal cells isolated from VIP KO naive mice produced lower levels of proinflammatory cytokines in response to LPS in vitro. Finally, decreased NF-?B pathway activity in peritoneal cells was observed both in vivo and in vitro, as determined by assay of phosphorylated I-?B. The results demonstrate that female VIP KO mice exhibit resistance to LPS-induced shock, explainable in part by the presence of an intrinsic defect in the responsiveness of inflammatory cells to endotoxin. PMID:22615845

Abad, Catalina; Tan, Yossan-Var; Cheung-Lau, Gardenia; Nobuta, Hiroko; Waschek, James A.

2012-01-01

321

Variation in the ovine cortisol response to systemic bacterial endotoxin challenge is predominantly determined by signalling within the hypothalamic-pituitary-adrenal axis  

SciTech Connect

Bi-directional communication between the neuroendocrine and immune systems is designed, in part, to maintain or restore homeostasis during physiological stress. Exposure to endotoxin during Gram-negative bacterial infection for example, elicits the release of pro-inflammatory cytokines that activate the hypothalamic-pituitary-adrenal axis (HPAA). The secretion of adrenal glucocorticoids subsequently down regulates the host inflammatory response, minimizing potential tissue damage. Sequence and epigenetic variants in genes involved in regulating the neuroendocrine and immune systems are likely to contribute to individual differences in the HPAA response, and this may influence the host anti-inflammatory response to toxin exposure and susceptibility to inflammatory disease. In this study, high (HCR) and low (LCR) cortisol responders were selected from a normal population of 110 female sheep challenged iv with Escherichia coli endotoxin (400 ng/kg) to identify potential determinants that contribute to variation in the cortisol response phenotype. This phenotype was stable over several years in the HCR and LCR animals, and did not appear to be attributed to differences in expression of hepatic immune-related genes or systemic pro-inflammatory cytokine concentrations. Mechanistic studies using corticotrophin-releasing factor (0.5 {mu}g/kg body weight), arginine vasopressin (0.5 {mu}g/kg), and adrenocorticotropic hormone (0.5 {mu}g/kg) administered iv demonstrated that variation in this phenotype is largely determined by signalling within the HPAA. Future studies will use this ovine HCR/LCR model to investigate potential genetic and epigenetic variants that may contribute to variation in cortisol responsiveness to bacterial endotoxin.

You Qiumei [Centre for Genetic Improvement of Livestock, Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Karrow, Niel A. [Centre for Genetic Improvement of Livestock, Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada)], E-mail: nkarrow@uoguelph.ca; Cao Honghe [Centre for Genetic Improvement of Livestock, Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Rodriguez, Alexander [Department of Clinical Studies, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Mallard, Bonnie A. [Department of Pathobiology, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Boermans, Herman J. [Department of Biomedical Science, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada)

2008-07-01

322

Selective detection of endotoxin using an impedance aptasensor with electrochemically deposited gold nanoparticles.  

PubMed

Using a single-stranded DNA (ssDNA) aptamer exhibiting high binding affinity (Kd?=?12?nM) to endotoxin as a probe, an impedance sensor where aptamer-conjugated gold nanoparticles (AuNPs) were electrochemically deposited on a gold electrode was fabricated and its performance in regard to endotoxin detection assessed. AuNPs have been employed widely as biosensors because of their unique physical and chemical properties. In order to maximize the performance of the impedance aptasensor on endotoxin detection, some critical factors affecting aptamer conjugation to AuNPs and target recognition ability (i.e. concentrations of aptamer coupled with AuNPs, pH, ion strength and cation effect at the time of aptamer-endotoxin interaction) were optimized. Electrochemical impendence spectroscopy, cyclic voltametry, atomic force microscope, scanning electron microscope and quartz crystal microbalance were employed to characterize all the modification/detection procedures during the sensor fabrication. The developed aptasensor showed a broad linear dynamic detection range (0.01-10.24?ng/ml) with a very low detection limit for endotoxin (0.005?ng/ml), despite the presence of several biomolecules (e.g. plasmid DNA, RNA, serum albumin, Glc and sucrose) known to interfere with other endotoxin assays. The demonstrated aptasensor required a detection time of only 10?min, providing a simple and fast analytical method to specifically detect endotoxin from complex biological liqors. PMID:23165992

Su, Wenqiong; Kim, Sung-Eun; Cho, MiSuk; Nam, Jae-Do; Choe, Woo-Seok; Lee, Youngkwan

2013-01-01

323

Escherichia Coli  

ERIC Educational Resources Information Center

Diverse biological data may be used to create illustrations of molecules in their cellular context. I describe the scientific results that support a recent textbook illustration of an "Escherichia coli cell". The image magnifies a portion of the bacterium at one million times, showing the location and form of individual macromolecules. Results…

Goodsell, David S.

2009-01-01

324

Recognition of bacterial lipopolysaccharide using bacteriophage-adhesin-coated long-period gratings.  

PubMed

In this paper we present a new type of highly sensitive label-free sensor based on long-period gratings (LPG) coated with T4 bacteriophage (phage) adhesin. The adhesin (gp37) binds Escherichia coli B (E. coli B) by recognizing its bacterial lipopolysaccharide (LPS). The LPG biofunctionalization methodology is based on coating LPG surface with nickel ions capable of gp37 histidine tag reversible binding. For the first time recombinant adhesive phage protein has been used as a receptor molecule in biosensing scheme. The specificity of LPS binding by adhesin has been tested with LPG-based device and confirmed using Western blot, Enzyme-Linked Immunosorbent Assay (ELISA) and BIACORE methods. The LPG-based sensor can measure bacterial contamination in real time and with a high accuracy. We show that T4 phage adhesin binds E. coli B LPS in its native or denatured form. The binding is highly specific and irreversible. The applied procedure allows for obtaining reusable biosensors. PMID:25067838

Brzozowska, Ewa; ?mietana, Mateusz; Koba, Marcin; Górska, Sabina; Pawlik, Krzysztof; Gamian, Andrzej; Bock, Wojtek J

2015-05-15

325

Household endotoxin levels and the risk of non-Hodgkin lymphoma  

PubMed Central

Objective Endotoxin, a component of the outer membrane of gram-negative bacteria, elicits a strong innate and inflammatory immune response associated with secretion of pro-inflammatory cytokines, including tumor necrosis factor-alpha (TNF-?). Because TNF-? polymorphisms that increase TNF-? production are associated with an increased risk of non-Hodgkin lymphoma (NHL), we hypothesized that increased levels of household endotoxin would be associated with an increased NHL risk. Methods We evaluated this association in the National Cancer Institute/Surveillance, Epidemiology and End Result (NCI/SEER) NHL multi-center population-based case-control study. Used vacuum cleaner bags were collected from participants during a home interview. Dust samples from the bags of 594 cases and 442 controls were analyzed for endotoxin (Endotoxin Unit [EU]/mg of dust) using the kinetic chromogenic Limulus amebocyte lysate assay. Multivariable logistic regression was used to estimate the effect of endotoxin on NHL risk adjusted for age, sex, race, education, study center, and farm exposure. Results Endotoxin was not associated with NHL overall (odds ratio [OR] for highest quartile of endotoxin levels = 0.81, 95% confidence interval [CI]= 0.55,1.20; P for trend=0.35), or with diffuse large B-cell lymphoma (OR= 0.63, 95% CI= 0.34, 1.16; P= 0.31) or follicular lymphoma (OR= 0.1.07, 95% CI=0.61, 1.89; P=0.73) subtypes. Both working and living on a farm were associated with higher household endotoxin levels compared to never working (P=0.009) or living (P=0.01) on a farm. Excluding farmers from the analysis did not change the results. Conclusions We found no evidence of a role for household endotoxin in NHL etiology. PMID:23277417

Wang, Jun; Cozen, Wendy; Thorne, Peter S.; Berhane, Kiros; Cerhan, James R.; Hartge, Patricia; Ward, Mary H.; De Roos, Anneclaire J.; Severson, Richard K.; Morton, Lindsay M.; Bernstein, Leslie; Linet, Martha S.; Colt, Joanne S.

2013-01-01

326

[Intestinal endotoxin in the pathogenesis of ocular inflammatory diseases and the antiendoxin constituent of its treatment].  

PubMed

Blood was studied in 119 patients with ocular inflammatory lesions: endophthalmitis (n = 10), iridocyclitis of viral (n = 47) and unknown (n = 62) genesis, by using the procedures developed by the authors to determine the integral values of the concentration of endotoxin in systemic blood flow and the activity of antiendotoxin immunity. Intestinal endotoxin aggression was found to be involved in the pathogenesis of ocular inflammatory diseases. The use of drugs and procedures, which could diminish the entry of intestinal endotoxin into the blood stream and intensify the processes of its binding and release from systemic blood circulation, substantially enhanced the efficiency of a therapeutic process. PMID:17526210

Vyshegurov, Ia Kh; Anikhovskaia, I A; Batmanov, Iu E; Iakovlev, M Iu

2007-01-01

327

The molecular adsorption-type endotoxin detection system using immobilized ?-polylysine  

NASA Astrophysics Data System (ADS)

Hemodialysis for chronic renal failure is the most popular treatment method with artificial organs. However, hemodialysis patients must continue the treatment throughout their life, the results of long term extracorporeal dialysis, those patients develop the various complications and diseases, for example, dialysis amyloidosis etc. Dialysis amyloidosis is one of the refractory complications, and endotoxin is thought to be the most likely cause of it, recently. Endotoxin is one of the major cell wall components of gram-negative bacteria, and it has various biological activities. In addition, it is known that a mount of endotoxin exists in living environment, and medicine is often contaminated with endotoxin. When contaminated dialyzing fluids are used to hemodialysis, above-mentioned dialysis amyloidosis is developed. Therefore, it is important that the detection and removal of endotoxin from dialyzing fluids. Until now, the measurement methods using Limulus Amebosyte Lysate (LAL) reagent were carried out as the tests for the presence of endtoxin. However, these methods include several different varieties of measurement techniques. The following are examples of them, gelatinization method, turbidimetric assay method, colorimetric assay method and fluoroscopic method. However, these techniques needed 30-60 minutes for the measurement. From these facts, they are not able to use as a "real-time endotoxin detector". The detection of endotoxin has needed to carry out immediately, for that reason, a new detection method is desired. In this research, we focused attention to adsorption reaction between ?-polylysine and endotoxin. ?-polylysine has the structure of straight chain molecule composed by 25-30 residues made by lysine, and it is used as an antimicrobial agent, moreover, cellulose beads with immobilized ?-polylysine is used as the barrier filter for endotoxin removal. The endotoxin is adsorbed to immobilized ?-polylysine, as the result of this reaction, the mass incrementation is occurred, and the existence of endtoxin can be detected immediately, by using of Quartz Crystal Microbalance (QCM). In this report, the immobilization of ?-polylysine onto the Au and Si substrate and its adsorptive activity are described. We use X-ray Photoelectron Spectroscopy (XPS) to confirm the ?-polylysine immobilization, and the adsorptive activity of immobilized ?-polylysine is measured by AFM and QCM. This molecular adsorption type endotoxin sensor aims to the realization of "real-time endotoxin detection system".

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

2007-12-01

328

Endotoxin in inner-city homes: Associations with wheeze and eczema in early childhood  

PubMed Central

Background An inverse association between domestic exposure to endotoxin and atopy in childhood has been observed. The relevance of this aspect of the “hygiene hypothesis” to U.S. inner-city communities that have disproportionately high asthma prevalence has not been determined. Objectives To measure endotoxin in the dust from inner-city homes, evaluate associations between endotoxin and housing/lifestyle characteristics, and determine whether endotoxin exposure predicted wheeze, allergic rhinitis and eczema over the first three years of life. Methods As part of an ongoing prospective birth cohort study, children of Dominican and African-American mothers living in New York City underwent repeated questionnaire measures. Dust samples collected from bedroom floors at age 12 or 36 months were assayed for endotoxin. Results Among the samples collected from 301 participant’s homes, the geometric mean endotoxin concentration [95% C.I.] was 75.9 EU/mg [66–87] and load was 3,892 EU/m2 [3,351–4,522]. Lower endotoxin concentrations were associated with wet mop cleaning and certain neighborhoods. Endotoxin concentration correlated weakly with cockroach (Bla g 2: r=0.22,p<0.001) and mouse (MUP: r=0.28,p<0.001) allergens in the dust. Children in homes with higher endotoxin concentration were less likely to have eczema at age 1 year (O.R. 0.70 [0.53–0.93]) and more likely to wheeze at age 2 years (O.R. 1.34 [1.01–1.78]). These associations were stronger among children with a maternal history of asthma. Conclusions Endotoxin levels in this inner-city community are similar to non-farm homes elsewhere. In this community, domestic endotoxin exposure was inversely associated with eczema at age 1, but positively associated with wheeze at age 2. Clinical Implications Endotoxin exposure in the inner-city community may be related to wheeze in the early life; however, given the inverse association seen with eczema, the long term development of allergic disease is still in question. PMID:16675336

Perzanowski, Matthew S.; Miller, Rachel L.; Thorne, Peter S.; Barr, R. Graham; Divjan, Adnan; Sheares, Beverley J.; Garfinkel, Robin S.; Perera, Frederica P.; Goldstein, Inge F.; Chew, Ginger L.

2007-01-01

329

Acquisition of the rfb-gnd Cluster in Evolution of Escherichia coli O55 and O157  

Microsoft Academic Search

The rfb region specifies the structure of lipopolysaccharide side chains that comprise the diverse gram- negative bacterial somatic (O) antigens. The rfb locus is adjacent to gnd, which is a polymorphic gene encoding 6-phosphogluconate dehydrogenase. To determine if rfb and gnd cotransfer, we sequenced gnd in five O55 and 13 O157 strains of Escherichia coli. E. coli O157:H7 has a

PHILLIP I. TARR; LAURA M. SCHOENING; YOO-LEE YEA; TERESA R. WARD; SRDJAN JELACIC; THOMAS S. WHITTAM

2000-01-01

330

Effect of dietary bovine colostrum on the responses of immune cells to stimulation with bacterial lipopolysaccharide.  

PubMed

Previous studies have revealed that ingestion of bovine colostrum is effective in preventing pathogens from invading through the gastrointestinal tract (GI) and modulating the mucosal immunity of the GI tract, indicating that its effect is principally local. Thus it is unclear if ingestion of bovine colostrum can affect the systemic immune system. In this study, we investigated the effect of taking bovine colostrum (vs phosphate-buffered saline) for 14 days on the behavior of the immune cells of mice. Isolated splenocytes, which are pivotal cells of systemic immunity, were then stimulated with Escherichia coli lipopolysaccharide. Bovine colostrum significantly reduced NK cell and monocyte activities and lymphoproliferaltive responses to LPS stimulation. Thus dietary bovine colostrum renders immune cells less responsive to LPS stimulation. Dietary bovine colostrum thus affects the systemic immune system and may have anti-inflammatory actions. PMID:24234910

Xu, Mei Ling; Kim, Hyoung Jin; Kim, Hong-Jin

2014-04-01

331

Overexpressing endothelial cell protein C receptor alters the hemostatic balance and protects mice from endotoxin.  

PubMed

Previous studies have shown that blocking endothelial protein C receptor (EPCR)-protein C interaction results in about an 88% decrease in circulating activated protein C (APC) levels generated in response to thrombin infusion and exacerbates the response to Escherichia coli. To determine whether higher levels of EPCR expression on endothelial cells might further enhance the activation of protein C and protect the host during septicemia, we generated a transgenic mouse (Tie2-EPCR) line which placed the expression of EPCR under the control of the Tie2 promoter. The mice express abundant EPCR on endothelial cells not only on large vessels, but also on capillaries where EPCR is generally low. Tie2-EPCR mice show higher levels of circulating APC after thrombin infusion. Upon infusion with factor Xa and phospholipids, Tie2-EPCR mice generate more APC, less thrombin and are protected from fibrin/ogen deposition compared with wild type controls. The Tie2-EPCR animals also generate more APC upon lipopolysaccharide (LPS) challenge and have a survival advantage. These results reveal that overexpression of EPCR can protect animals against thrombotic or septic challenge. PMID:15978090

Li, W; Zheng, X; Gu, J; Hunter, J; Ferrell, G L; Lupu, F; Esmon, N L; Esmon, C T

2005-07-01

332

The “Genomic Storm” Induced by Bacterial Endotoxin Is Calmed by a Nuclear Transport Modifier That Attenuates Localized and Systemic Inflammation  

PubMed Central

Lipopolysaccharide (LPS) is a potent microbial virulence factor that can trigger production of proinflammatory mediators involved in the pathogenesis of localized and systemic inflammation. Importantly, the role of nuclear transport of stress responsive transcription factors in this LPS-generated “genomic storm” remains largely undefined. We developed a new nuclear transport modifier (NTM) peptide, cell-penetrating cSN50.1, which targets nuclear transport shuttles importin ?5 and importin ?1, to analyze its effect in LPS-induced localized (acute lung injury) and systemic (lethal endotoxic shock) murine inflammation models. We analyzed a human genome database to match 46 genes that encode cytokines, chemokines and their receptors with transcription factors whose nuclear transport is known to be modulated by NTM. We then tested the effect of cSN50.1 peptide on proinflammatory gene expression in murine bone marrow-derived macrophages stimulated with LPS. This NTM suppressed a proinflammatory transcriptome of 37 out of 84 genes analyzed, without altering expression of housekeeping genes or being cytotoxic. Consistent with gene expression analysis in primary macrophages, plasma levels of 23 out of 26 LPS-induced proinflammatory cytokines, chemokines, and growth factors were significantly attenuated in a murine model of LPS-induced systemic inflammation (lethal endotoxic shock) while the anti-inflammatory cytokine, interleukin 10, was enhanced. This anti-inflammatory reprogramming of the endotoxin-induced genomic response was accompanied by complete protection against lethal endotoxic shock with prophylactic NTM treatment, and 75% protection when NTM was first administered after LPS exposure. In a murine model of localized lung inflammation caused by direct airway exposure to LPS, expression of cytokines and chemokines in the bronchoalveolar space was suppressed with a concomitant reduction of neutrophil trafficking. Thus, calming the LPS-triggered “genomic storm” by modulating nuclear transport with cSN50.1 peptide attenuates the systemic inflammatory response associated with lethal shock as well as localized lung inflammation. PMID:25329889

Moore, Daniel J.; Wylezinski, Lukasz S.; Hutchens, Martha A.; Hawiger, Jacek

2014-01-01

333

Differential roles of PKA and Epac on the production of cytokines in the endotoxin-stimulated primary cultured microglia.  

PubMed

To further understand the anti-inflammatory effect of adenosine cyclic 3',5'-monophosphate (cAMP), we examined the effect of protein kinase A (PKA) and cAMP-responsive guanine nucleotide exchange factor (Epac) on the transcription and production of cytokines and on the activity of mitogen-activated protein kinases (MAPK) p38 and glycogen synthase kinase-3? (GSK-3?) in endotoxin-treated rat primary cultured microglia. The PKA specific agonist N6-benzoyladenosine-3,5-cAMP (6-Bnz-cAMP) not only inhibited the transcription and production of tumor necrosis factor-? (TNF-?) and interleukin-1? (IL-1?) but also enhanced the transcription and expression of IL-10, while the Epac selective analog 8-(4-chlorophenylthio)-2-O-methyladenosine-3,5-cAMP (8-pCPT-2'-O-Me-cAMP) merely repressed the TNF-? expression. Western blots assays indicated that 6-Bnz-cAMP significantly inhibited lipopolysaccharide-induced activation of both p38 and GSK-3? in a dose-dependent manner; in contrast, 8-pCPT-2'-O-Me-cAMP only slightly repressed GSK-3? activity at large doses. Pretreatment with H-89, a specific PKA antagonist, could completely reverse the effect of 6-Bnz-cAMP on cytokines expressions and kinases activities but had no effect on the performance of 8-pCPT-2'-O-Me-cAMP. Our findings indicate that PKA and Epac exert differential effect on the expression of inflammatory cytokines such as TNF-?, IL-1?, and IL-10, possibly owing to the different effects on the downstream effectors, MAPK p38, and GSK-3?. PMID:20640531

Liu, Jian; Zhao, Xin; Cao, Jianping; Xue, Qingsheng; Feng, Xiaomei; Liu, Xuesheng; Zhang, Fujun; Yu, Buwei

2011-10-01

334

Inhibition of Aldose Reductase Prevents Endotoxin-Induced Inflammation by Regulating Arachidonic Acid Pathway in Murine Macrophages  

PubMed Central

Bacterial endotoxin, lipopolysaccharide (LPS) is known to induce release of arachidonic acid (AA) and its metabolic products which play important role in inflammatory process. We have shown earlier that LPS-induced signals in macrophages are mediated by aldose reductase (AR). Here we have investigated the role of AR in LPS-induced release of AA metabolites and their modulation using a potent pharmacological inhibitor fidarestat and AR-siRNA ablation in RAW 264.7 macrophages, and AR-knockout mice peritoneal macrophages and heart tissue. Inhibition or genetic ablation of AR prevented the LPS-induced synthesis and release of AA metabolites such as PGE2, TXB, PGI2 and LTBs in macrophages. LPS-induced activation of cPLA2 was also prevented by AR inhibition. Similarly, AR inhibition also prevented the calcium ionophore A23187 –induced cPLA2 and LTB4 in macrophages. Further, AR inhibition with fidarestat prevented the expression of AA metabolizing enzymes such as COX-2 and LOX-5 in RAW 264.7 cells and AR-knockout mice derived peritoneal macrophages. LPS-induced expression of AA metabolizing enzymes and their catalyzed metabolic products were significantly lower in peritoneal macrophages and heart tissue from AR-knockout mice. LPS-induced activation of redox-sensitive signaling intermediates such as MAPKs, transcription factor NF-kB as well as Egr-1, a transcription regulator of mPGES-1, which in collaboration with COX-2 leads to the production of PGE2, were also significantly prevented by AR inhibition. Taken together, our results indicate that AR mediates LPS-induced inflammation by regulating AA metabolic pathway and thus provide novel role of AR inhibition in preventing inflammatory complications such as sepsis. PMID:21856412

Shoeb, Mohammad; Yadav, Umesh CS; Srivastava, Satish K; Ramana, Kota V

2011-01-01

335

Involvement of tyrosine kinase in the induction of cyclo-oxygenase and nitric oxide synthase by endotoxin in cultured cells.  

PubMed Central

1. Cyclo-oxygenase (COX) and nitric oxide synthase (NOS) are two enzymes which have distinct cytokine-inducible isoforms (COX-2 and iNOS). Many cytokine receptors have an intracellular tyrosine kinase domain. Here we have used the tyrosine kinase inhibitors, erbstatin and genistein, to investigate the potential role of tyrosine kinase activation in the induction on COX-2 and iNOS caused by endotoxin (lipopolysaccharide; LPS) in bovine aortic endothelial cells (BAEC) and J774.2 macrophages. 2. The main COX metabolites, 6-oxo-prostaglandin F1 alpha (6-oxo-PGF1 alpha) (for BAEC) and PGF2 alpha (for 774.2 macrophages) were measured by radioimmunossay: (i) accumulation of COX metabolites from endogenous arachidonic acid was measured at 24 h after addition of LPS (1 microgram ml-1); (ii) in experiments designed to measure 'COX activity', COX metabolites generated by BAEC or J774.2 macrophages activated with LPS were assayed (at 12 h after LPS administration) after incubation of the washed cells with exogenous arachidonic acid (30 microM for 15 min). Western blot analysis with a specific antibody to COX-2 was used to determine the expression of COX-2 protein caused by LPS in cell extracts. Accumulation of nitrite (measured by the Griess reaction) was used as an indicator of NO formation and, hence, iNOS activity. 3. Erbstatin (0.05 to 5 micrograms ml-1) or genistein (0.5 to 50 micrograms ml-1) caused a dose-dependent inhibition of the accumulation of COX metabolites in the supernatant of BAEC or J774.2 macrophages activated with LPS. Erbstatin or genistein also caused a dose-dependent inhibition of 'COX activity' in both cell types.(ABSTRACT TRUNCATED AT 250 WORDS) Images Figure 4 PMID:7534189

Akarasereenont, P; Mitchell, J A; Appleton, I; Thiemermann, C; Vane, J R

1994-01-01

336

THYMIDINE DIPHOSPHATE-L-RHAMNOSE METABOLISM IN SMOOTH AND ROUGH STRAINS OF ESCHERICHIA COLI AND SALMONELLA WESLACO.  

PubMed

Okazaki, Tuneko (Washington University School of Medicine, St. Louis, Mo.), Jack L. Stominger, and Reiji Okazaki. Thymidine diphosphate-l-rhamnose metabolism in smooth and rough strains of Escherichia coli and Salmonella weslaco. J. Bacteriol. 86:118-124. 1963.-Logarithmic-phase cells of Escherichia coli O18, which have rhamnose in their lipopolysaccharide, contained only traces of thymidine diphosphate (TDP)-l-rhamnose. Extracts of this organism, however, catalyzed the synthesis of TDP-l-rhamnose from TDP-d-glucose. On the other hand, cells of E. coli R44, a rough variant of this strain which contains no rhamnose in its lipopolysaccharide, contained a large amount of TDP-l-rhamnose. Like the smooth form, this organism was able to synthesize TDP-l-rhamnose. The rough variant is apparently a mutant blocked in some manner in utilization of TDP-l-rhamnose for lipopolysaccharide synthesis. Similar studies of smooth (rhamnose-containing) and rough (rhamnose-lacking) forms of Salmonella weslaco showed that both organisms can synthesize TDP-l-rhamnose from TDP-d-glucose. In contrast to the smooth and rough forms of E. coli O18, only traces of TDP-l-rhamnose were detected in extracts of both forms. A second thymidine diphosphosugar compound isolated from E. coli R44 is similar or identical to TDP-X, previously isolated from E. coli Y-10. PMID:14051803

OKAZAKI, T; STROMINGER, J L; OKAZAKI, R

1963-07-01

337

THYMIDINE DIPHOSPHATE-l-RHAMNOSE METABOLISM IN SMOOTH AND ROUGH STRAINS OF ESCHERICHIA COLI AND SALMONELLA WESLACO  

PubMed Central

Okazaki, Tuneko (Washington University School of Medicine, St. Louis, Mo.), Jack L. Stominger, and Reiji Okazaki. Thymidine diphosphate-l-rhamnose metabolism in smooth and rough strains of Escherichia coli and Salmonella weslaco. J. Bacteriol. 86:118–124. 1963.—Logarithmic-phase cells of Escherichia coli O18, which have rhamnose in their lipopolysaccharide, contained only traces of thymidine diphosphate (TDP)-l-rhamnose. Extracts of this organism, however, catalyzed the synthesis of TDP-l-rhamnose from TDP-d-glucose. On the other hand, cells of E. coli R44, a rough variant of this strain which contains no rhamnose in its lipopolysaccharide, contained a large amount of TDP-l-rhamnose. Like the smooth form, this organism was able to synthesize TDP-l-rhamnose. The rough variant is apparently a mutant blocked in some manner in utilization of TDP-l-rhamnose for lipopolysaccharide synthesis. Similar studies of smooth (rhamnose-containing) and rough (rhamnose-lacking) forms of Salmonella weslaco showed that both organisms can synthesize TDP-l-rhamnose from TDP-d-glucose. In contrast to the smooth and rough forms of E. coli O18, only traces of TDP-l-rhamnose were detected in extracts of both forms. A second thymidine diphosphosugar compound isolated from E. coli R44 is similar or identical to TDP-X, previously isolated from E. coli Y-10. Images PMID:14051803

Okazaki, Tuneko; Strominger, Jack L.; Okazaki, Reiji

1963-01-01

338

NMR-based structural analysis of the complete rough-type lipopolysaccharide isolated from Capnocytophaga canimorsus.  

PubMed

We here describe the NMR analysis of an intact lipopolysaccharide (LPS, endotoxin) in water with 1,2-dihexanoyl-sn-glycero-3-phosphocholine as detergent. When HPLC-purified rough-type LPS of Capnocytophaga canimorsus was prepared, (13)C,(15)N labeling could be avoided. The intact LPS was analyzed by homonuclear ((1)H) and heteronuclear ((1)H,(13)C, and (1)H,(31)P) correlated one- and two-dimensional NMR techniques as well as by mass spectrometry. It consists of a penta-acylated lipid A with an ?-linked phosphoethanolamine attached to C-1 of GlcN (I) in the hybrid backbone, lacking the 4'-phosphate. The hydrophilic core oligosaccharide was found to be a complex hexasaccharide with two mannose (Man) and one each of 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo), Gal, GalN, and l-rhamnose residues. Position 4 of Kdo is substituted by phosphoethanolamine, also present in position 6 of the branched Man(I) residue. This rough-type LPS is exceptional in that all three negative phosphate residues are "masked" by positively charged ethanolamine substituents, leading to an overall zero net charge, which has so far not been observed for any other LPS. In biological assays, the corresponding isolated lipid A was found to be endotoxically almost inactive. By contrast, the intact rough-type LPS described here expressed a 20,000-fold increased endotoxicity, indicating that the core oligosaccharide significantly contributes to the endotoxic potency of the whole rough-type C. canimorsus LPS molecule. Based on these findings, the strict view that lipid A alone represents the toxic center of LPS needs to be reassessed. PMID:24993825

Zähringer, Ulrich; Ittig, Simon; Lindner, Buko; Moll, Hermann; Schombel, Ursula; Gisch, Nicolas; Cornelis, Guy R

2014-08-22

339

Exogenous normal lymph reduces liver injury induced by lipopolysaccharides in rats  

PubMed Central

The liver is one of the target organs damaged by septic shock, wherein the spread of endotoxins begins. This study aimed to investigate the effects of exogenous normal lymph (ENL) on lipopolysaccharide (LPS)-induced liver injury in rats. Male Wistar rats were randomly divided into sham, LPS, and LPS+ENL groups. LPS (15 mg/kg) was administered intravenously via the left jugular vein to the LPS and LPS+ENL groups. At 15 min after the LPS injection, saline or ENL without cell components (5 mL/kg) was administered to the LPS and LPS+ENL groups, respectively, at a rate of 0.5 mL/min. Hepatocellular injury indices and hepatic histomorphology, as well as levels of P-selectin, intercellular adhesion molecule 1 (ICAM-1), myeloperoxidase (MPO), and Na+-K+-ATPase, were assessed in hepatic tissues. Liver tissue damage occurred after LPS injection. All levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in plasma as well as the wet/dry weight ratio of hepatic tissue in plasma increased. Similarly, P-selectin, ICAM-1, and MPO levels in hepatic tissues were elevated, whereas Na+-K+-ATPase activity in hepatocytes decreased. ENL treatment lessened hepatic tissue damage and decreased levels of AST, ALT, ICAM-1, and MPO. Meanwhile, the treatment increased the activity of Na+-K+-ATPase. These results indicated that ENL could alleviate LPS-induced liver injury, thereby suggesting an alternative therapeutic strategy for the treatment of liver injury accompanied by severe infection or sepsis. PMID:24519128

Zhao, Z.G.; Zhang, L.L.; Niu, C.Y.; Zhang, J.

2014-01-01

340

Heterogeneity in lipopolysaccharide responsiveness of endothelial cells identified by gene expression profiling: role of transcription factors  

PubMed Central

Interindividual differences of endothelial cells in response to endotoxins might contribute to the diversity in clinical outcome among septic patients. The present study was conducted to test the hypothesis that endothelial cells (EC) with high and low proinflammatory potential exist and to dissect the molecular basis underlying this phenomenon. Thirty human umbilical vein endothelial cell (HUVEC) lines were stimulated for 24 h with lipopolysaccharide (LPS) and screened for interleukin (IL)-8 production. Based on IL-8 production five low and five high producers, tentatively called types I and II responders, respectively, were selected for genome-wide gene expression profiling. From the 74 genes that were modulated by LPS in all type II responders, 33 genes were not influenced in type I responders. Among the 41 genes that were increased in both responders, 17 were expressed significantly stronger in type II responders. Apart from IL-8, significant differences in the expression of proinflammatory related genes between types I and II responders were found for adhesion molecules [intercellular adhesion molecule (ICAM-1), E-selectin)], chemokines [monocyte chemoattractant protein (MCP-1), granulocyte chemotactic protein (GCP-2)], cytokines (IL-6) and the transcription factor CCAAT/enhancer binding protein-delta (C/EBP-?). Type I responders also displayed a low response towards tumour necrosis factor (TNF)-?. In general, maximal activation of nuclear factor (NF)-?B was achieved in type I responders at higher concentrations of LPS compared to type II responders. In the present study we demonstrate that LPS-mediated gene expression differs quantitatively and qualitatively in types I and II responders. Our results suggest a pivotal role for common transcription factors as a low inflammatory response was also observed after TNF-? stimulation. Further studies are required to elucidate the relevance of these findings in terms of clinical outcome in septic patients. PMID:16487252

Beck, G C; Rafat, N; Brinkkoetter, P; Hanusch, C; Schulte, J; Haak, M; van Ackern, K; van der Woude, F J; Yard, B A

2006-01-01

341

Characterization of a rabbit cationic protein (CAP18) with lipopolysaccharide-inhibitory activity.  

PubMed Central

Cationic antibacterial proteins (CAP) were purified from rabbit granulocytes, and the effects of CAP on lipopolysaccharide (LPS)-induced tissue factor generation by murine peritoneal macrophages and human blood monocytes were studied. CAP were purified from rabbit peritoneal leukocytes by using as an assay the agglutination of erythrocytes coated with Re-LPS. Two proteins with CAP activity, CAP18 (18 kDa) and CAP7 (7 kDa), were isolated by acid extraction, ethanol precipitation, affinity chromatography, gel filtration, and reverse-phase high-pressure liquid chromatography. On the basis of protein sequencing, CAP7 was identified as the C-terminal fragment of CAP18, designated CAP18(106-142). Various forms of LPS (S-LPS, Re-LPS, and lipid A) activate murine macrophages and human blood monocytes to generate tissue factor (tissue thromboplastin). Incubation of LPS for 18 h with partially purified CAP (heparin-Sepharose fraction) inhibited the capacity of LPS to induce tissue factor; however, purified CAP18 inhibited about 75% of the activity of S-LPS after 1 h of incubation. CAP more effectively inhibited S-LPS than Re-LPS or lipid A. Synthetic CAP18(106-142) inhibited LPS-induced tissue factor generation by murine macrophages. CAP18(106-142) has greater LPS-binding and LPS-neutralizing activities than CAP18. We hypothesize that CAP18 and the derivative peptide, CAP18(106-142), bind to LPS and alter the capacity of LPS to initiate disseminated intravascular coagulation. In this regard, CAP may have therapeutic potential for sepsis and endotoxin shock. Images PMID:8132348

Hirata, M; Shimomura, Y; Yoshida, M; Morgan, J G; Palings, I; Wilson, D; Yen, M H; Wright, S C; Larrick, J W

1994-01-01

342

Evaluation of the serotonin receptor blocker methiothepin in broilers injected intravenously with lipopolysaccharide and microparticles.  

PubMed

There has been considerable interest in the role of serotonin (5-hydroxytryptamine, 5-HT) in the pathogenesis of pulmonary hypertension due to episodes of primary pulmonary hypertension in humans linked to serotoninergic appetite-suppressant drugs. In this study, we investigated the effect of 5-HT on the development of pulmonary hypertension induced by injecting bacterial lipopolysaccharide (LPS; endotoxin) and cellulose microparticles intravenously, using the nonselective 5-HT(1/2)receptor, antagonist methiothepin. In Experiment 1, broilers selected for ascites susceptibility or resistance under conditions of hypobaric hypoxia were treated with methiothepin or saline, followed by injection of LPS, while recording pulmonary arterial pressure (PAP). In Experiment 2 ascites-susceptible broilers were treated with methiothepin or saline, followed by injection of cellulose microparticles, while recording PAP. In Experiment 3, an i.v. microparticle injection dose shown to cause 50% mortality was injected into ascites-susceptible and ascites-resistant broilers after methiothepin or saline treatment. Injecting methiothepin reduced PAP below baseline values in ascites-susceptible and ascites-resistant broilers, suggesting a role for 5-HT in maintaining the basal tone of the pulmonary vasculature in broilers. Injecting microparticles into the wing vein had no affect on the PAP in the broilers treated with methiothepin, suggesting that 5-HT is an important mediator in the pulmonary hypertensive response of broilers to microparticles. Furthermore, injecting an 50% lethal dose of microparticles into ascites-susceptible and ascites-resistant broilers pretreated with methiothepin resulted in reduced mortality. Serotonin appears to play a less prominent role in the pulmonary hypertensive response of broilers to intravenously injected LPS, indicating that other mediators within the innate response to inflammatory stimuli may also be involved. These results are consistent with our hypothesis that pulmonary hypertension syndrome ensues when vasoconstrictors, such as 5-HT, overwhelm the dilatory effects of vasodilators, such as NO, thereby effectively reducing the pulmonary vascular capacity of pulmonary hypertension syndrome-susceptible broilers. PMID:17135680

Chapman, M E; Wideman, R F

2006-12-01

343

Time course of defense mechanisms in bovine endometrium in response to lipopolysaccharide.  

PubMed

Endometritis caused by uterine infection after calving reduces fertility and causes major economic losses to the dairy industry. This study investigated the time course of an inflammatory response in bovine endometrium triggered by exposure to bacterial endotoxin lipopolysaccharide (LPS). Mixed endometrial epithelial and stromal cells (9:1 ratio) were grown to confluence as a model system and treated with an optimized dose of 100 ng/ml LPS in vitro. Gene expression responses were measured using quantitative PCR, and gene products were investigated using assays of culture medium and Western blotting. Of 17 candidate genes tested initially, LPS treatment for 24 h up-regulated mRNA expression of TLR4 signaling (TLR4, CD14), cytokines (IL1B, TNF), chemokines (IL8, CXCL5), antimicrobial peptides (LAP, S100A8, S100A9, S100A12), and matrix metalloproteinases (MMP1, MMP13). A 48 h, LPS time course study showed that TNF increased first at 1 h, followed by peak expression of IL1B at 6 h, and those of S100A8, S100A12, and LAP at 12 h. The intracellular S100A8 protein content doubled at 12-24 h but with little excretion into the medium. Regarding prostaglandin biosynthesis, PTGES mRNA was slightly higher after LPS exposure, whereas expression of the PGF synthase AKR1B1 was inhibited. Despite this, LPS treatment stimulated the secretion of both PGE? and PGF?(alpha) to a similar extent. These results suggest that the family of S100 Ca˛? binding proteins are released from damaged endometrial cells and may play a major antimicrobial role. Prostaglandin synthesis increased during the uterine infection, but we found no evidence that this was associated with a change in the PGE:PGF ratio. PMID:23077171

Swangchan-Uthai, Theerawat; Lavender, Chloe R M; Cheng, Zhangrui; Fouladi-Nashta, Ali A; Wathes, D Claire

2012-06-01

344

Differential Inflammatory Response to Inhaled Lipopolysaccharide Targeted Either to the Airways or the Alveoli in Man  

PubMed Central

Endotoxin (Lipopolysaccharide, LPS) is a potent inducer of inflammation and there is various LPS contamination in the environment, being a trigger of lung diseases and exacerbation. The objective of this study was to assess the time course of inflammation and the sensitivities of the airways and alveoli to targeted LPS inhalation in order to understand the role of LPS challenge in airway disease. In healthy volunteers without any bronchial hyperresponsiveness we targeted sequentially 1, 5 and 20 µg LPS to the airways and 5 µg LPS to the alveoli using controlled aerosol bolus inhalation. Inflammatory parameters were assessed during a 72 h time period. LPS deposited in the airways induced dose dependent systemic responses with increases of blood neutrophils (peaking at 6 h), Interleukin-6 (peaking at 6 h), body temperature (peaking at 12 h), and CRP (peaking at 24 h). 5 µg LPS targeted to the alveoli caused significantly stronger effects compared to 5 µg airway LPS deposition. Local responses were studied by measuring lung function (FEV1) and reactive oxygen production, assessed by hydrogen peroxide (H2O2) in fractionated exhaled breath condensate (EBC). FEV1 showed a dose dependent decline, with lowest values at 12 h post LPS challenge. There was a significant 2-fold H2O2 induction in airway-EBC at 2 h post LPS inhalation. Alveolar LPS targeting resulted in the induction of very low levels of EBC-H2O2. Targeting LPS to the alveoli leads to stronger systemic responses compared to airway LPS targeting. Targeted LPS inhalation may provide a novel model of airway inflammation for studying the role of LPS contamination of air pollution in lung diseases, exacerbation and anti-inflammatory drugs. PMID:22496751

Möller, Winfried; Heimbeck, Irene; Hofer, Thomas P. J.; Khadem Saba, Gülnaz; Neiswirth, Margot; Frankenberger, Marion; Ziegler-Heitbrock, Löms

2012-01-01

345

Diffuse lamellar keratitis related to endotoxins released from sterilizer reservoir biofilms  

Microsoft Academic Search

ObjectiveTo investigate the risk factors and control mechanisms used to control the outbreak of diffuse lamellar keratitis (DLK) associated with laser in situ keratomileusis (LASIK) and examine the relationship between DLK and endotoxins released from sterilizer biofilm reservoirs.

Simon P Holland; Richard G Mathias; Douglas W Morck; Jonathan Chiu; Stephen G Slade

2000-01-01

346

Cyanobacterial lipopolysaccharides and human health – a review  

PubMed Central

Cyanobacterial lipopolysaccharide/s (LPS) are frequently cited in the cyanobacteria literature as toxins responsible for a variety of heath effects in humans, from skin rashes to gastrointestinal, respiratory and allergic reactions. The attribution of toxic properties to cyanobacterial LPS dates from the 1970s, when it was thought that lipid A, the toxic moiety of LPS, was structurally and functionally conserved across all Gram-negative bacteria. However, more recent research has shown that this is not the case, and lipid A structures are now known to be very different, expressing properties ranging from LPS agonists, through weak endotoxicity to LPS antagonists. Although cyanobacterial LPS is widely cited as a putative toxin, most of the small number of formal research reports describe cyanobacterial LPS as weakly toxic compared to LPS from the Enterobacteriaceae. We systematically reviewed the literature on cyanobacterial LPS, and also examined the much lager body of literature relating to heterotrophic bacterial LPS and the atypical lipid A structures of some photosynthetic bacteria. While the literature on the biological activity of heterotrophic bacterial LPS is overwhelmingly large and therefore difficult to review for the purposes of exclusion, we were unable to find a convincing body of evidence to suggest that heterotrophic bacterial LPS, in the absence of other virulence factors, is responsible for acute gastrointestinal, dermatological or allergic reactions via natural exposure routes in humans. There is a danger that initial speculation about cyanobacterial LPS may evolve into orthodoxy without basis in research findings. No cyanobacterial lipid A structures have been described and published to date, so a recommendation is made that cyanobacteriologists should not continue to attribute such a diverse range of clinical symptoms to cyanobacterial LPS without research confirmation. PMID:16563160

Stewart, Ian; Schluter, Philip J; Shaw, Glen R

2006-01-01

347

[Plasma endotoxin, procalcitonin, C-reactive protein, and organ functions in patients with major burns].  

PubMed

Sepsis is one of the most frequent causes of death after major burn injury. Usually, sepsis appears as a consequence of a gram-negative bacteriaemia with release of endotoxins. In this study, the plasma endotoxin levels of seven patients (three female, four male; average age 51.3 +/- 23.8 years) with burns between 43.5 and 78 % Total Body Surface Area (Abbreviated Burn Severity Index 8 - 12) were determined for five days after thermal trauma every three hours by ELISA and compared with the concentration of procalcitonin (PCT) and C-reactive protein (CRP). A calculation of the Horrowitz-Index (PaO(2)/FiO(2)) and the Pressure-Adjusted Heart Rate (HR x CVP/MAP) took place to show a possible correlation between the endotoxin concentration and the cardiopulmonary organ function. Additionally, we analysed whether operative treatment can influence the level of plasma endotoxin in the early phase after burn injury. At any time after burn trauma, endotoxins could be detected in the plasma of all patients. Between the second and third day, there was a considerable increase in the endotoxin concentration with a maximum after 57 hours of 0.48 +/- 0.32 EU/ml. Two patients with sepsis and death in the further course had a rather distinctive increase. From the fourth day on, occasional episodes of increases in endotoxin concentration were noted. Postoperatively, there was a short increase in plasma endotoxin on the second and fourth day. The plasma endotoxin level showed no correlation with the PCT and CRP or with the oxygenation in the patients' blood. However, a positive correlation could be observed with the Pressure-Adjusted Heart Rate (p = 0.0061; r(2) = 0.212). An explanation for the endotoxin increase after 57 hours could be the translocation of intestinal bacteria, the beginning of bacterial colonisation or decomposition products of the burn wound with protein-protein complexes. Later on, infectious diseases such as pneumonia with gram-negative bacteria are of importance, too. According to the Two-Hit Model, the increase of plasma endotoxin can serve as a trigger and cause a recurrence of systemic inflammation with the changes observed in cardiac organ function, multiple organ dysfunction, and multiple organ failure. PMID:11518988

Ulrich, D; Noah, E M; Pallua, N

2001-07-01

348

Levels of gram-negative bacteria, Aspergillus fumigatus, dust, and endotoxin at compost plants.  

PubMed Central

Airborne gram-negative bacteria, endotoxins, dust, and Aspergillus fumigatus were measured in four compost plants in Sweden. At sites where material was processed, the number of airborne A. fumigatus exceeded 10(6)/m3, whereas the number of gram-negative bacteria was usually lower. Dust levels were moderate, and endotoxin levels were well below 0.5 micrograms/m3. Medical studies to evaluate the effects of this type of microbial exposure are recommended. PMID:6347061

Clark, C S; Rylander, R; Larsson, L

1983-01-01

349

Expression of calgranulin A/B heterodimer after acute inhalation of endotoxin: proteomic approach and validation  

PubMed Central

Background The acute inhalation of endotoxin mimicks several aspects of the inflammation related to chronic obstructive pulmonary disease (COPD). The aim of the current study was to identify and to validate biomarkers of endotoxin-induced airways’ inflammation. Methods The cellular count in the induced-sputum, was measured before and after an inhalation of 20 mcg endotoxin, in 8 healthy volunteers. A proteomic analysis was applied to identify the more relevant proteins expression, before measurement by ELISA. The amplitude and the repeatability of the markers were evaluated among another population of 12 healthy subjects. Results There was a significant rise of viable cells (p <0.01), macrophages (p <0.05), and neutrophils (p <0.02) 24 hours after endotoxin inhalation, and of neutrophils (p <0.02) and lymphocytes (p <0.05) at 6 hours. Among the highest amplitude responses, the two dimensional electrophoretic separation shown proteolytic activity and overexpression of protein spots. By MALDI-TOF mass spectrometry, the last were identified as calgranulin A and B. The expression of the bioactive A/B heterodimeric complex was confirmed by ELISA both in the sputum (p <0.01) and at the blood level (p <0.01). The intra-subject repeatability of the sputum calgranulin A/B was highly significant (p <0.0001). Conclusion In healthy subjects, the inhalation of endotoxin induced expression of sputum calgranulin A/B that could be a biomarker of the endotoxin response/exposure. PMID:24237763

2013-01-01

350

Pulmonary hypertensive response to endotoxin in cellulose-primed and unprimed broiler chickens.  

PubMed

Previous studies indicate that individual broilers vary widely in their pulmonary vascular responsiveness to i.v. injections of endotoxin. This individual variability may reflect differences acquired during previous respiratory challenges or genetic variability that may be associated with susceptibility to pulmonary hypertension syndrome (ascites). In the present study, we compared the endotoxin responses of 4- to 5- wk-old control broilers (unprimed) and broilers in which the pulmonary vasculature had been immunologically challenged 48 h previously by an i.v. injection of cellulose micro-particles (primed). The injected cellulose micro-particles are carried in the venous blood to the lungs, where they become trapped in the pulmonary vasculature and initiate acute focal inflammatory responses within the surrounding lung parenchyma. Physiological variables (respiratory rate, heart rate, pulmonary and systemic arterial pressures) were evaluated prior to and following the i.v. administration of 1 mg of Salmonella typhimurium endotoxin. Prior to endotoxin injection, the respiratory rate was higher in primed than in unprimed broilers; however, the heart rate, pulmonary arterial pressure, and systemic arterial pressure did not differ between groups. Broilers in both groups exhibited similar ranges of individual variability in their endotoxin responses. The overall time of onset, magnitude, and duration of the pulmonary hypertensive responses were similar for both groups. Accordingly, the initiation of a preexisting inflammatory response within the lung parenchyma did not alter the timing, amplitude, or variability of the subsequent pulmonary hypertensive response to endotoxin in broilers. PMID:12211316

Wang, W; Wideman, R F; Erf, G F

2002-08-01

351

BACILLUS THURINGIENSIS VAR ISRAELENSIS CRYSTAL 6ENDOTOXIN: EFFECTS ON INSECT AND MAMMALIAN CELLS IN VITRO AND IN VIVO  

Microsoft Academic Search

SUMMARY Bacillus thuringiensis var israelensis parasporal crystal 5-endotoxin was purified by ultracentri- fugation on a discontinuous sucrose gradient. Native 6-endotoxin crystals showed no detectable toxicity in the in vitro and in vivo systems that are described. By contrast alkali-solubilized crystal 6-endotoxin caused rapid cytological and cytopathological changes in Aedes alboptctus, Chons- toneura fumiferana 63 CF1, Spodoptera frugiperda and Trichoplusia ni

WENDY E. THOMAS; DAVID J. ELLAR

1983-01-01

352

Resistance to Endotoxin Shock and Reduced Dissemination of Gram-Negative Bacteria in CD14Deficient Mice  

Microsoft Academic Search

Endotoxin shock is the result of activation of the immune system by endotoxin\\/LPS, a component of Gram-negative bacteria. CD14, a GPI-anchored glycoprotein expressed strongly by monocyte\\/macrophages, is one of several receptors for endotoxin\\/LPS. The role of CD14 in bacterial-induced and LPS-induced shock was tested in CD14-deficient mice produced by gene targeting in embryonic stem cells. CD14-deficient mice were found to

Alain Haziot; Enza Ferrero; Frank Köntgen; Naoki Hijiya; Shunsuke Yamamoto; Jack Silver; Colin L Stewart; Sanna M Goyert

1996-01-01

353

Analysis of the cell wall and lipopolysaccharide of Spirillum serpens.  

PubMed

Isolated walls of Spirillum serpens VHA contained lipid, lipopolysaccharide, and protein in amounts similar to those of other gram-negative organisms. The loosely bound lipids consisted mainly of phosphatidylethanolamine, lyso-phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol. Lipopolysaccharide was tightly bound to the wall and could only be removed in a substantial amount after digestion of the wall with Pronase. The lipopolysaccharide contained L-glycero-D-mannoheptose, rhamnose, glucosamine, ethanolamine, and phosphate in common with many of the lipopolysaccharides isolated from the Enterobacteriaceae. However, 2-keto-3-deoxyoctonic acid was not detected. Several unidentified sugars were present. The fatty acid composition resembled that found in lipopolysaccharides isolated from various pseudomonads. Two major regions were identified in the polysaccharide moiety, one apparently corresponding to the core polysaccharide and the other corresponding to the side-chain polysaccharide as in enterobacterial and pseudomonad lipopolysaccharides. The side chains were obtained as low-molecular-weight material and their structure was partially elucidated by the isolation and partial characterization of N-acetylglucosaminyl-(1 leads to 4)-rhamnose. PMID:1194232

Chester, I R; Murray, R G

1975-12-01

354

In vivo effects of endotoxin on intraepithelial mucosubstances in rat pulmonary airways. Quantitative histochemistry.  

PubMed Central

Bacteria-induced bronchopneumonias are often characterized by an influx of neutrophils and excess mucus in pulmonary airways. This study determined how endotoxin, a component of gram-negative bacteria and a potent inflammatory agent, affects the ultrastructure of the mucociliary apparatus and the amount of stored intraepithelial mucosubstances in the main axial airways within the lung. Rats were intranasally instilled, once a day for 3 days, with endotoxin or saline (controls). Animals were sacrificed 1, 2, or 7 days after the last instillation. Microdissected intrapulmonary axial airways (generations 8-11) from the right caudal lobes of infusion-fixed lungs were processed for light and electron microscopy. Morphometric techniques were used to determine the volume densities (Vs) of histochemically stained intraepithelial mucosubstances and numerical densities of airway epithelial cells. There were marked increases, compared with controls, in the amount of intraepithelial mucosubstances in the intrapulmonary axial airways at generations 8 and 11 in the right caudal lobes from endotoxin-instilled rats sacrificed 1, 2, and 7 days after the last instillation. There were significantly greater numbers of surface epithelial cells per length of basal lamina (i.e., hyperplasia) in endotoxin-exposed airways compared with airways from controls. This endotoxin-induced hyperplasia was due primarily to an increase in the number of mucus-secretory cells, which in endotoxin-exposed epithelium were columnar and contained numerous, large confluent, electronlucent, secretory granules composed of acidic and neutral glycoproteins. In contrast, secretory cells in airway epithelium from controls were cuboidal and contained small discrete, electron-dense, granules composed of only neutral glycoproteins. The numbers of ciliated cells and basal cells were similar in both control and endotoxin-exposed epithelium. Only endotoxin-exposed epithelium, however, contained atypical epithelial cells with numerous basal bodies, few cilia, and few apical secretory granules. These results indicate that repeated airway instillations of endotoxin induce an increase in the amount of intraepithelial mucosubstances, secretory cell hyperplasia, and excess luminal mucus in pulmonary airways. Therefore, endotoxin released from gram-negative bacteria may be partially responsible for the structural alterations, in the airway surface epithelium, which result in the excess luminal mucus observed in bacteria-induced bronchopneumonias. Images Figure 1 Figure 2 Figure 5 Figure 6 PMID:1497089

Harkema, J. R.; Hotchkiss, J. A.

1992-01-01

355

The Alternative Pathway is critical for Pathogenic Complement Activation in Endotoxin- and Diet-induced Atherosclerosis in Low-Density Lipoprotein Receptor-Deficient Mice  

PubMed Central

Background The early components of the classical and lectin complement pathways have been shown to protect low-density lipoprotein receptor deficient mice (Ldlr?/?) from early atherogenesis. However, the role of the alternative pathway remained unknown and that was investigated in this study. Methods and Results Mice lacking factor B (Bf?/?), the initiator of the alternative pathway, were crossed with Ldlr?/? mice and studied under different pro-atherogenic conditions. There was no statistically significant difference in lipid profiles or atherosclerotic lesion development between Bf?/?.Ldlr?/? and Ldlr?/? mice fed a low-fat diet. However, in these groups administration of bacterial lipopolysaccharide (LPS) led to a significant increase in atherosclerosis only in Ldlr?/? and not in Bf?/?.Ldlr?/? mice, indicating that the alternative pathway is necessary for endotoxin-mediated atherogenesis. Bf?/?.Ldlr?/? mice also had significantly decreased cross-sectional aortic root lesion fraction area and reduced lesion complexity compared to Ldlr?/? animals after a 12-week period of high-fat diet, although this was also accompanied by reduced levels of serum cholesterol. Under both experimental conditions, the atherosclerotic changes in the Bf?/?.Ldlr?/? mice were accompanied by a marked reduction in complement activation in the circulation and in atherosclerotic plaques, with no statistical significant differences in IgG deposition or in the serum antibody response to oxidised LDL. Conclusions These data demonstrate that amplification of complement activation by the alternative pathway in response to LPS or high fat diet plays a pro-atherogenic role. PMID:20974996

Malik, Talat H.; Cortini, Andrea; Carassiti, Daniele; Boyle, Joseph J; Haskard, Dorian O.; Botto, Marina

2010-01-01

356

A signal-on electrochemical aptasensor for ultrasensitive detection of endotoxin using three-way DNA junction-aided enzymatic recycling and graphene nanohybrid for amplification.  

PubMed

Endotoxin, also known as lipopolysaccharide (LPS), is able to induce a strong immune response on its internalization into mammalian cells. To date, aptamer-based biosensors for LPS detection have been rarely reported. This work describes a new signal-on electrochemical aptasensor for the ultrasensitive detection of LPS by combining the three-way DNA hybridization process and nanotechnology-based amplification. With the help of DNA1 (associated with the concentration of target LPS), the capture probe hybridizes with DNA1 and the assistant probe to open its hairpin structure and form a ternary "Y" junction structure. The DNA1 can be released from the structure in the presence of nicking endonuclease to initiate the next hybridization process. Then a great deal of cleaved capture probe produced in the cyclic process can bind with DNA2-nanocomposite, which contains the electroactive toluidine blue (Tb) with the amplification materials graphene (Gra) and gold nanoparticles (AuNPs). Thus, an enhanced electrochemical signal can be easily read out. With the cascade signal amplification, this newly designed protocol provides an ultrasensitive electrochemical detection of LPS down to the femtogram level (8.7 fg mL(-1)) with a linear range of 6 orders of magnitude (from 10 fg mL(-1) to 50 ng mL(-1)). Moreover, the high sensitivity and specificity make this method versatile for the detection of other biomolecules by changing the corresponding sequences of the capture probe and the assistant probe. PMID:24477782

Bai, Lijuan; Chai, Yaqin; Pu, Xiaoyun; Yuan, Ruo

2014-03-01

357

A signal-on electrochemical aptasensor for ultrasensitive detection of endotoxin using three-way DNA junction-aided enzymatic recycling and graphene nanohybrid for amplification  

NASA Astrophysics Data System (ADS)

Endotoxin, also known as lipopolysaccharide (LPS), is able to induce a strong immune response on its internalization into mammalian cells. To date, aptamer-based biosensors for LPS detection have been rarely reported. This work describes a new signal-on electrochemical aptasensor for the ultrasensitive detection of LPS by combining the three-way DNA hybridization process and nanotechnology-based amplification. With the help of DNA1 (associated with the concentration of target LPS), the capture probe hybridizes with DNA1 and the assistant probe to open its hairpin structure and form a ternary ``Y'' junction structure. The DNA1 can be released from the structure in the presence of nicking endonuclease to initiate the next hybridization process. Then a great deal of cleaved capture probe produced in the cyclic process can bind with DNA2-nanocomposite, which contains the electroactive toluidine blue (Tb) with the amplification materials graphene (Gra) and gold nanoparticles (AuNPs). Thus, an enhanced electrochemical signal can be easily read out. With the cascade signal amplification, this newly designed protocol provides an ultrasensitive electrochemical detection of LPS down to the femtogram level (8.7 fg mL-1) with a linear range of 6 orders of magnitude (from 10 fg mL-1 to 50 ng mL-1). Moreover, the high sensitivity and specificity make this method versatile for the detection of other biomolecules by changing the corresponding sequences of the capture probe and the assistant probe.

Bai, Lijuan; Chai, Yaqin; Pu, Xiaoyun; Yuan, Ruo

2014-02-01

358

Electrochemical biosensor array for the identification of microorganisms based on lectin-lipopolysaccharide recognition.  

PubMed

Rapid identification of bacterial strains remains a well-known problem in applied medicine and, for viable pathogens, is an important diagnostic goal. We have investigated an electrochemical biosensor array, in which transduction is based on respiratory cycle activity measurements, where the microorganism's native respiratory chain is interrupted with non-native external oxidants. The selective biochemical recognition agents employed in this study are lectins that, once immobilized, recognize and bind to cell surface lipopolysaccharides. Porous membranes with different surface properties were examined as potential immobilization supports for these lectins. Optimizations performed using concanavalin A and E. coli JM105 show that immobilization methods involving pre-activated membranes significantly reduce the time required to create a functional lectin layer on the membrane surface. Overall, we found general agreement between agglutination test results and the electrochemical assessment of lectin-cell binding. Chronocoulometric measurements were made for cells captured on lectin-modified Immunodyne ABC membranes physically affixed to Pt working electrodes. This lectin-based sensor array was exposed to viable cells of gram-negative and gram-positive bacteria as well as yeast, and chronocoulometric measurements were used to generate a pattern of responses for each organism toward each lectin. Principal component analysis was used to classify the chronocoulometric results for the different microbial strains. With this new method, six microbial species (Baccilus cereus, Staphylococcus aureus, Proteus vulgaris, Escherichia coli, Enterobacter aerogenes, Saccharomyces cerevisiae) were readily distinguished. PMID:11569815

Ertl, P; Mikkelsen, S R

2001-09-01

359

Long-term interdisciplinary therapy reduces endotoxin level and insulin resistance in obese adolescents  

PubMed Central

Aim The purpose of the present study was to assess the dietary fat intake, glucose, insulin, Homeostasis model assessment for insulin resistance HOMA-IR, and endotoxin levels and correlate them with adipokine serum concentrations in obese adolescents who had been admitted to long-term interdisciplinary weight-loss therapy. Design The present study was a longitudinal clinical intervention of interdisciplinary therapy. Adolescents (n?=?18, aged 15–19 y) with a body mass index?>?95th percentile were admitted and evaluated at baseline and again after 1 year of interdisciplinary therapy. We collected blood samples, and IL-6, adiponectin, and endotoxin concentrations were measured by ELISA. Food intake was measured using 3-day diet records. In addition, we assessed glucose and insulin levels as well as the homeostasis model assessment for insulin resistance (HOMA-IR). Results The most important finding from the present investigation was that the long-term interdisciplinary lifestyle therapy decreased dietary fat intake and endotoxin levels and improved HOMA-IR. We observed positive correlations between dietary fat intake and endotoxin levels, insulin levels, and the HOMA-IR. In addition, endotoxin levels showed positive correlations with IL-6 levels, insulin levels and the HOMA-IR. Interestingly, we observed a negative correlation between serum adiponectin and both dietary fat intake and endotoxin levels. Conclusions The present results indicate an association between dietary fat intake and endotoxin level, which was highly correlated with a decreased pro-inflammatory state and an improvement in HOMA-IR. In addition, this benefits effect may be associated with an increased adiponectin level, which suggests that the interdisciplinary therapy was effective in improving inflammatory pathways. PMID:22989045

2012-01-01

360

Diagnostic potential of endotoxin scattering photometry for sepsis and septic shock.  

PubMed

Endotoxin scattering photometry (ESP) is a novel Limulus amebocyte lysate (LAL) assay that uses a laser light-scattering particle-counting method. In the present study, we compared ESP, standard turbidimetric LAL assay, and procalcitonin assay for the evaluation of sepsis after emergency gastrointestinal surgery. A total of 174 samples were collected from 40 adult patients undergoing emergency gastrointestinal surgery and 10 patients with colorectal cancer undergoing elective surgery as nonseptic controls. Plasma endotoxin levels were measured with ESP and turbidimetric LAL assay, and plasma procalcitonin levels were assessed with a standard procalcitonin assay. Plasma endotoxin and procalcitonin levels increased corresponding to the degree of sepsis. Endotoxin scattering photometry significantly discriminated between patients with or without septic shock: sensitivity, 81.1%; specificity, 76.6%; positive predictive value, 48.4%; negative predictive value, 93.8%; and accuracy, 77.6%. The area under the receiver operating characteristic curve for septic shock with the ESP assay (endotoxin cutoff value, 23.8 pg/mL) was 0.8532 ± 0.0301 (95% confidence interval, 0.7841-0.9030; P < 0.0001). The predictive power of ESP was superior to that of turbidimetric assay (difference, 0.1965 ± 0.0588; 95% confidence interval, 0.0812-0.3117; P = 0.0008). There was no significant difference in predictive power between ESP and procalcitonin assay. Endotoxin scattering photometry also discriminated between patients with and without sepsis. Area under the receiver operating characteristic curve analysis showed that ESP had the best predictive power for diagnosing sepsis. In conclusion, compared with turbidimetric LAL assay, ESP more sensitively detected plasma endotoxin and significantly discriminated between sepsis and septic shock in patients undergoing gastrointestinal emergency surgery. PMID:24089007

Shimizu, Tomoharu; Obata, Toru; Sonoda, Hiromichi; Akabori, Hiroya; Miyake, Tohru; Yamamoto, Hiroshi; Tabata, Takahisa; Eguchi, Yutaka; Tani, Tohru

2013-12-01

361

Association of Endotoxins and Colon Polyp: A Case-Control Study  

PubMed Central

Endotoxins are known to be associated with the occurrence of various chronic diseases. This study was conducted to investigate the role of endotoxins in the pathogenesis of colon polyps through a case-control study. A total of 145 subjects (74 subjects in the polyp group and 71 subjects in the control group) had undergone a colonoscopy. Age, body mass index (BMI) and endotoxin levels were found to be significantly higher in the polyp group than in the control group. The endotoxin level was still significantly higher in the polyp group than in the control group, even after age and BMI had been adjusted (polyp group 0.108 ± 0.007 EU/mL, control group 0.049 ± 0.008 EU/mL, P < 0.001). In subgroup analysis, the endotoxin level significantly increased in accordance with the number of colon polyps (one-polyp group, 0.088 ± 0.059 EU/mL; two-polyp group, 0.097 ± 0.071 EU/mL; three-or-more-polyp group, 0.149 ± 0.223 EU/mL). The endotoxin levels also significantly increased in groups with tubular adenoma with high-grade dysplasia (hyperplastic polyp group, 0.109 ± 0.121 EU/mL; tubular adenoma with low grade dysplasia group, 0.103 ± 0.059 EU/mL; tubular adenoma with high grade dysplasia group, 2.915 ± 0.072 EU/mL). In conclusion, the serum level of endotoxins is quantitatively correlated with colon polyps. PMID:22969253

Lee, Kang-Kon

2012-01-01

362

Lipopolysaccharide induced conversion of recombinant prion protein.  

PubMed

The conformational conversion of the cellular prion protein (PrP(C)) to the ?-rich infectious isoform PrP(Sc) is considered a critical and central feature in prion pathology. Although PrP(Sc) is the critical component of the infectious agent, as proposed in the "protein-only" prion hypothesis, cellular components have been identified as important cofactors in triggering and enhancing the conversion of PrP(C) to proteinase K resistant PrP(Sc). A number of in vitro systems using various chemical and/or physical agents such as guanidine hydrochloride, urea, SDS, high temperature, and low pH, have been developed that cause PrP(C) conversion, their amplification, and amyloid fibril formation often under non-physiological conditions. In our ongoing efforts to look for endogenous and exogenous chemical mediators that might initiate, influence, or result in the natural conversion of PrP(C) to PrP(Sc), we discovered that lipopolysaccharide (LPS), a component of gram-negative bacterial membranes interacts with recombinant prion proteins and induces conversion to an isoform richer in ? sheet at near physiological conditions as long as the LPS concentration remains above the critical micelle concentration (CMC). More significant was the LPS mediated conversion that was observed even at sub-molar ratios of LPS to recombinant ShPrP (90-232). PMID:24819168

Saleem, Fozia; Bjorndahl, Trent C; Ladner, Carol L; Perez-Pineiro, Rolando; Ametaj, Burim N; Wishart, David S

2014-01-01

363

Comparison of the rabbit pyrogen test and Limulus amoebocyte lysate (LAL) assay for endotoxin in hepatitis B vaccines and the effect of aluminum hydroxide  

Microsoft Academic Search

The rabbit pyrogen test and Limulus amoebocyte lysate (LAL) assay have been used to detect endotoxins in vaccines, but interactions between the endotoxins and proteins or aluminum hydroxide can interfere with the results. Currently, the rabbit pyrogen test is used to detect endotoxin in hepatitis B (HB) vaccines even though the HB surface protein, the active ingredient, is over-expressed in

Chul-Yong Park; Seung-Ha Jung; Jong-Phil Bak; Sun-Suk Lee; Dong-Kwon Rhee

2005-01-01

364

Effect of deployment time on endotoxin and allergen exposure assessment using electrostatic dust collectors.  

PubMed

The electrostatic dust collector (EDC) is a passive dust sampling device for exposure assessment of airborne endotoxin and possibly allergens. EDCs consist of a non-conducting plastic folder holding two or four electrostatic cloths of defined area. The sampling time needed to achieve detectable and reproducible loading for bioaerosols has not been systematically evaluated. Thus, in 15 Iowa farm homes EDCs were deployed for 7-, 14-, and 28-day sampling periods to determine if endotoxin and allergens could be quantified and if loading rates were uniform over time, i.e. if loads doubled from 7 to 14 days or 14 to 28 days and quadrupled from 7 to 28 days. Loadings between left and right paired EDC cloths were not significantly different and were highly correlated for endotoxin, total protein, and cat (Fel d1), dog (Can f1), and mouse (Mus m1) allergens (P < 0.001). EDCs performed especially well for endotoxin sampling with close agreement between paired samples (Pearson r = 0.96, P < 0.001). Endotoxin loading of the EDCs doubled from 7- to 14-day deployments as hypothesized although the loading rate decreased from 14 to 28 days of sampling with only a 1.38-fold increase. Allergen exposure assessment using EDCs was overall less satisfactory. Although there was reasonable agreement between paired samples, only exposures to cat, dog, and mouse allergens were reliable and these only at the longer deployment times. PMID:25187036

Kilburg-Basnyat, Brita; Metwali, Nervana; Thorne, Peter S

2015-01-01

365

Effects of Endotoxin and Psychological Stress on Redox Physiology, Immunity and Feather Corticosterone in Greenfinches  

PubMed Central

Assessment of costs accompanying activation of immune system and related neuroendocrine pathways is essential for understanding the selective forces operating on these systems. Here we attempted to detect such costs in terms of disruption to redox balance and interference between different immune system components in captive wild-caught greenfinches (Carduelis chloris). Study birds were subjected to an endotoxin-induced inflammatory challenge and temporary exposure to a psychological stressor (an image of a predator) in a 2*2 factorial experiment. Injection of bacterial endotoxin resulted in up-regulation of two markers of antioxidant protection – erythrocyte glutathione, and plasma oxygen radical absorbance (OXY). These findings suggest that inflammatory responses alter redox homeostasis. However, no effect on markers of oxidative damage to proteins or DNA in erythrocytes could be detected. We found no evidence that the endotoxin injection interfered with antibody production against Brucella abortus antigen or the intensity of chronic coccidiosis. The hypothesis of within-immune system trade-offs as a cost of immunity was thus not supported in our model system. We showed for the first time that administration of endotoxin can reduce the level of corticosterone deposited into feathers. This finding suggests a down-regulation of the corticosterone secretion cascade due to an endotoxin-induced immune response, a phenomenon that has not been reported previously. Exposure to the predator image did not affect any of the measured physiological parameters. PMID:23805316

Meitern, Richard; Sild, Elin; Lind, Mari-Ann; Männiste, Marju; Sepp, Tuul; Karu, Ulvi; Hőrak, Peeter

2013-01-01

366

Indoor and outdoor particulate matter and endotoxin concentrations in an intensely agricultural county  

PubMed Central

The objectives of this study were to characterize rural populations’ indoor and outdoor exposure to PM10, PM2.5, and endotoxin and identify factors that influence these concentrations. Samples were collected at 197 rural households over five continuous days between 2007 and 2011. Geometric mean indoor PM10 (21.2 ?g m?3) and PM2.5 (12.2 ?g m?3) concentrations tended to be larger than outdoor PM10 (19.6 ?g m?3) and PM2.5 (8.2 ?g m?3) concentrations (PM10 p= 0.086; PM2.5 p <0.001). Conversely, GM outdoor endotoxin concentrations (1.93 EU m?3) were significantly larger than indoor (0.32 EU m?3) (p<0.001). Compared to measurements from previous urban studies, indoor and outdoor concentrations of PM10 and PM2.5 in the study area tended to be smaller while, ambient endotoxin concentrations measured outside rural households were 3-10 times larger. Contrary to our initial hypothesis, seasonality did not have a significant effect on mean ambient PM10 concentrations; however, endotoxin concentrations in the autumn were almost seven-times larger than winter. Excluding home cleanliness, the majority of agricultural and housing characteristics evaluated were found to be poorly associated with indoor and outdoor particulate and endotoxin concentrations. PMID:23321860

Pavilonis, Brian T.; Anthony, T. Renee; O’Shaughnessy, Patrick T.; Humann, Michael J.; Merchant, James A.; Moore, Genna; Thorne, Peter S.; Weisel, Clifford P.; Sanderson, Wayne T.

2014-01-01

367

PREPARATION AND HOST-REACTIVE PROPERTIES OF ENDOTOXIN WITH LOW CONTENT OF NITROGEN AND LIPID  

PubMed Central

Endotoxins of low lipid content prepared from S. enteritidis by the aqueous ether method have been further treated to remove bound lipid by non-hydrolytic procedures. Such endotoxins, containing as little as 2 per cent lipid A, were as potent in stimulating a variety of physiological responses as those prepared by the well known phenol-water or Boivin procedures which yield products containing as much as 30 per cent lipid A. To verify the difference in lipid content between the aqueous ether preparations and other types of endotoxins, three different methods of lipid analysis were employed: determination of chloroform-soluble material released by hydrolysis with hydrochloric acid (lipid A) or with acetic acid (lipid W), and estimation of total bound fatty acids. These methods were in accord in showing the magnitude of the difference. No more than one-half of the fatty acids present in endotoxin were associated with the fraction designated lipid A. Methods are described for the preparation of potent endotoxins with analytical values for nitrogen, phosphorus, hexosamine, carbohydrate, and fatty acid which do not differ appreciably from those of the classical, non-toxic, haptenic polysaccharides. PMID:14491836

Ribi, Edgar; Haskins, Willard T.; Landy, Maurice; Milner, Kelsey C.

1961-01-01

368

Measurement of airborne bacteria and endotoxin generated during dental cleaning.  

PubMed

Dynamic dental instruments generate abundant aerosols in the work environment. Dental unit waterlines (DUWL) support a large microbial population and can be a significant source of bioaerosols generated during dental treatments. This study was conducted to characterize bioaerosol generation during dental treatments performed in standardized conditions. Culture-based method (R2A, and blood agar with and without O2) and fluorescence microscopy were used. Dental cleaning procedures were performed in an isolated treatment room with controlled ventilation rate. Andersen microbial samplers were used to collect culturable bioaerosols generated before (baseline), during, and after 2 hr of dental treatments. Inhalable dust samplers were used to measure total bioaerosols content in dental hygienist's and patients' breathing zones. AGI-30 were used for the collection of the endotoxin. The use of fluorescence microscopy in combination with culture demonstrated that dental staff and patients were exposed to up to 1.86 E+05 bacteria/m(3) generated during treatments. Fortunately, bioaerosols returned to baseline within 2 hr after the dental procedures. The small diameter of the aerosols generated (< 1 microm) suggests that the risk of contact between the aerosolized bacteria and the respiratory system of exposed individuals is likely to occur. PMID:19093289

Dutil, Steve; Meriaux, Anne; de Latremoille, Marie-Chantale; Lazure, Louis; Barbeau, Jean; Duchaine, Caroline

2009-02-01

369

Endotoxin binding by sevelamer: potential impact on nutritional status.  

PubMed

Patients on hemodialysis (HD) have a high burden of chronic inflammation induced associated with multiple comorbidities including poor nutritional status. Endotoxin (ET) is a Gram-negative bacterial cell wall component and a potent stimulus for innate immune system activation leading to the transcription of proinflammatory cytokines (e.g., IL-1, IL-6, and TNF?) that adversely affect protein metabolism and nutrition. Several cross-sectional observational studies have found that elevated serum ET concentrations in hemodialysis patients are associated with lower serum albumin, higher proinflammatory cytokine, and C-reactive protein concentrations. Possible sources of ET in the systemic circulation are bacterial translocation from the gastrointestinal tract and iron supplementation, potentially leading to intestinal bacterial overgrowth. Sevelamer is a nonabsorbable hydrogel approved for use as a phosphate binder in HD patients. Reductions in serum ET concentrations in hemodialysis patients have been observed with sevelamer therapy in observational studies and the few published interventional studies. Reduction of ET concentrations was associated with concomitant reductions in TNF?, IL-6, and CRP and improvement in serum albumin in the majority of these small studies. Additional studies are needed to evaluate the potential effects of sevelamer treatment on nutritional status in chronic kidney disease (CKD) patients with elevated ET. PMID:23401772

Kubotera, Natsuki; Prokopienko, Alexander J; Garba, Adinoyi O; Pai, Amy Barton

2013-01-01

370

Effect of endotoxin challenge on hepatic 5'-deiodinase activity in cattle.  

PubMed

Thyroid status is compromised in a variety of acute and chronic infections and toxin-mediated disease states. Conversion of thyroxine (T4) into the metabolically active hormone, triiodothyronine (T3), is catalyzed by 5'-deiodinase (5'D). Our objective was to determine the effect of endotoxin (LPS) challenge with and without L-arginine (Arg) infusion on hepatic activity of 5'D and plasma concentrations of T4 and T3. In a 2 x 2 factorial, beef heifers (275-310 kg b.wt.) were fed low (8% CP; 6.5 kg/d) or high (14% CP; 7.2 kg/d) isocaloric protein diets (1.96 Mcal/kg DM) for 10 d before LPS challenge. L-Arginine in saline (0.5 g/kg b.wt.) or saline alone was infused i.v. throughout an 8 hr period starting 2 hr before bolus LPS injection (Escherichia coli, 055: B5; 0.2 microg/kg; i.v.). Blood samples were collected at -2, 0, 3, 6, 12, and 24 hr relative to LPS injection. Liver samples were obtained 20 hr before, and then 6 and 24 hr after LPS challenge using a biopsy needle. Plasma T4 and T3 concentrations were not affected by dietary CP or Arg. Compared with levels at 0 hr, LPS challenge decreased plasma T4 (P < 0.01) and T3 (P < 0.001), respectively, 8.4% and 28.9% at 6 hr and 19.7% and 31.3% at 24 hr. Consistent with these changes, the T3:T4 ratio was lower than that at 0 hr (P < 0.001) 22.0% at 6 hr and 13.5% at 24 hr. Hepatic 5'D activities 20 hr before LPS injection were 2.80 +/- 0.11 nmol I- x hr(-1) x mg protein(-1) and decreased 24 hr after LPS, respectively, 45.4% (P < 0.01) and 17.6% (P < 0.05) in saline- and Arg-infused heifers. The results indicate that mild LPS challenge in cattle inhibits hepatic generation of T3 and decreases plasma concentrations of thyroid hormones. The data also suggest that the impact of LPS on 5'D activity in liver can be altered by Arg supplementation. PMID:10701770

Kahl, S; Elsasser, T H; Blum, J W

2000-01-01

371

Innate Immune Programing by Endotoxin and Its Pathological Consequences  

PubMed Central

Monocytes and macrophages play pivotal roles in inflammation and homeostasis. Recent studies suggest that dynamic programing of macrophages and monocytes may give rise to distinct “memory” states. Lipopolysaccharide (LPS), a classical pattern recognition molecule, dynamically programs innate immune responses. Emerging studies have revealed complex dynamics of cellular responses to LPS, with high doses causing acute, resolving inflammation, while lower doses are associated with low-grade and chronic non-resolving inflammation. These phenomena hint at dynamic complexities of intra-cellular signaling circuits downstream of the Toll-like receptor 4 (TLR4). In this review, we examine pathological effects of varying LPS doses with respect to the dynamics of innate immune responses and key molecular regulatory circuits responsible for these effects. PMID:25610440

Morris, Matthew C.; Gilliam, Elizabeth A.; Li, Liwu

2015-01-01

372

Amide-mediated hydrogen bonding at organic crystal/water interfaces enables selective endotoxin binding with picomolar affinity.  

PubMed

Since the discovery of endotoxins as the primary toxic component of Gram-negative bacteria, researchers have pursued the quest for molecules that detect, neutralize, and remove endotoxins. Selective removal of endotoxins is particularly challenging for protein solutions and, to this day, no general method is available. Here, we report that crystals of the purine-derived compound allantoin selectively adsorb endotoxins with picomolar affinity through amide-mediated hydrogen bonding in aqueous solutions. Atom force microscopy and chemical inhibition experiments indicate that endotoxin adsorption is largely independent from hydrophobic and ionic interactions with allantoin crystals and is mediated by hydrogen bonding with amide groups at flat crystal surfaces. The small size (500 nm) and large specific surface area of allantoin crystals results in a very high endotoxin-binding capacity (3 × 10(7) EU/g) which compares favorably with known endotoxin-binding materials. These results provide a proof-of-concept for hydrogen bond-based molecular recognition processes in aqueous solutions and establish a practical method for removing endotoxins from protein solutions. PMID:23611466

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

2013-05-22

373

Contribution of the individual components of the ?-endotoxin crystal to the mosquitocidal activity of Bacillus thuringiensis subsp. israelensis  

Microsoft Academic Search

The ?-endotoxin crystal of the mosquitocidal bacterium Bacillus thuringiensis subsp. israelensis contains four major 0-endotoxins. Expression systems were devised to synthesize each of the four toxins at concentrations at which they formed inclusion bodies in an acrystalliferous mutant of Bacillus thuringiensis. The relative activities of these inclusions were then determined against Aedes aegypti larvae. Bioassays of mixtures of the individual

Neil Crickmore; Eileen J. Bone; Juliet A. Williams; David J. Ellar

1995-01-01

374

Lipopolysaccharides mediate leukotoxin secretion in Aggregatibacter actinomycetemcomitans  

PubMed Central

SUMMARY We previously reported that lipopolysaccharide (LPS) related sugars are associated with the glycosylation of the collagen adhesin EmaA, a virulence determinant of Aggregatibacter actinomycetemcomitans. In this study, the role of LPS in the secretion of other virulence factors was investigated. The secretion of the epithelial adhesin Aae, the immunoglobulin Fc receptor Omp34 and leukotoxin were examined in a mutant strain with inactivated TDP-4-keto-6-deoxy-d-glucose 3,5-epimerase (rmlC), which resulted in altered O-antigen polysaccharides (O-PS) of LPS. The secretion of Aae and Omp34 was not affected. However, the leukotoxin secretion, which is mediated by the TolC-dependent Type I secretion system, was altered in the rmlC mutant. The amount of secreted leukotoxin in the bacterial growth medium was reduced 9-fold, with a concurrent 4-fold increase of the membrane-bound toxin in the mutant compared with the wild type strain. The altered leukotoxin secretion pattern was restored to the wild-type by complementation of the rmlC gene in trans. Examination of the ltxA mRNA levels indicated that the leukotoxin secretion was posttranscriptionally regulated in the modified O-PS containing strain. The mutant strain also showed increased resistance to vancomycin, an antibiotic dependent on TolC for internalization, indicating that TolC was affected. Overexpression of TolC in the rmlC mutant resulted in an increased TolC level in the outer membrane but did not restore the leukotoxin secretion profile to the wild-type phenotype. The data suggest that O-PS mediate leukotoxin secretion in A. actinomycetemcomitans. PMID:22394466

Tang, Gaoyan; Kawai, Toshihisa; Komatsuzawa, Hitoshi; Mintz, Keith P.

2011-01-01

375

Structural and thermodynamic analyses of the interaction between melittin and lipopolysaccharide.  

PubMed

Lipopolysaccharide (LPS), the major constituent of the outer membrane of Gram-negative bacteria, is the very first site of interactions with the antimicrobial peptides. In this work, we have determined a solution conformation of melittin, a well-known membrane active amphiphilic peptide from honey bee venom, by transferred nuclear Overhauser effect (Tr-NOE) spectroscopy in its bound state with lipopolysaccharide. The LPS bound conformation of melittin is characterized by a helical structure restricted only to the C-terminus region (residues A15-R24) of the molecule. Saturation transfer difference (STD) NMR studies reveal that several C-terminal residues of melittin including Trp19 are in close proximity with LPS. Isothermal titration calorimetry (ITC) data demonstrates that melittin binding to LPS or lipid A is an endothermic process. The interaction between melittin and lipid A is further characterized by an equilibrium association constant (Ka) of 2.85 x 10(6) M(-1) and a stoichiometry of 0.80, melittin/lipid A. The estimated free energy of binding (delta G0), -8.8 kcal mol(-1), obtained from ITC experiments correlates well with a partial helical structure of melittin in complex with LPS. Moreover, a synthetic peptide fragment, residues L13-Q26 or mel-C, derived from the C-terminus of melittin has been found to contain comparable outer membrane permeabilizing activity against Escherichia coli cells. Intrinsic tryptophan fluorescence experiments of melittin and mel-C demonstrate very similar emission maxima and quenching in presence of LPS micelles. The Red Edge Excitation Shift (REES) studies of tryptophan residue indicate that both peptides are located in very similar environment in complex with LPS. Collectively, these results suggest that a helical conformation of melittin, at its C-terminus, could be an important element in recognition of LPS in the outer membrane. PMID:17854761

Bhunia, Anirban; Domadia, Prerna N; Bhattacharjya, Surajit

2007-12-01

376

Expression of interleukin 1 alpha and beta, and interleukin 1 receptor antagonist mRNA in the rat central nervous system after peripheral administration of lipopolysaccharides.  

PubMed

Interleukin 1alpha (IL-1alpha) and IL-1beta, and the endogenous IL-1 receptor antagonist (IL-1ra) are known members of the IL-1 family. Using in situ hybridization histochemistry we demonstrated that following endotoxin injection (lipopolysaccharides, LPS, 2.0 mg/kg, i.p.) a time dependent expression and partly different expression patterns of the cytokines occurred within the rat brain and pituitary gland. All cytokines were observed in the choroid plexus. In addition, IL-1ra mRNA expressing cells were observed scattered in the brain parenchyma, whereas scattered IL-1beta mRNA expressing cells were restricted to central thalamic nuclei, the dorsal hypothalamus, and cortical regions, such as the parietal and frontal cortex. A strong IL-1beta mRNA expression was found in the circumventricular organs. In the pituitary gland, a low IL-1alpha and a high IL-1beta mRNA expression was observed, with the highest density of cytokine-expressing cells seen in the posterior pituitary. The cell types expressing the mRNA's of IL-1alpha, IL-1beta and IL-1ra were identified as monocytes in the circumventricular organs and the pituitary gland, and as microglia in the brain parenchyma. In conclusion, the present findings revealed that cytokine production in response to a peripheral endotoxin challenge mainly occurs in peripherally derived monocytes in the circumventricular organs and the pituitary gland. IL-1beta is the predominant form expressed, whereas the expression of IL-1alpha mRNA and IL-1ra mRNA is lower. Our observations support the view that peripherally derived IL-1 may play a role in the induction of centrally mediated illness symptoms. PMID:10857755

Eriksson, C; Nobel, S; Winblad, B; Schultzberg, M

2000-05-01

377

Diarrheagenic Escherichia coli  

PubMed Central

Escherichia coli is the predominant nonpathogenic facultative flora of the human intestine. Some E. coli strains, however, have developed the ability to cause disease of the gastrointestinal, urinary, or central nervous system in even the most robust human hosts. Diarrheagenic strains of E. coli can be divided into at least six different categories with corresponding distinct pathogenic schemes. Taken together, these organisms probably represent the most common cause of pediatric diarrhea worldwide. Several distinct clinical syndromes accompany infection with diarrheagenic E. coli categories, including traveler’s diarrhea (enterotoxigenic E. coli), hemorrhagic colitis and hemolytic-uremic syndrome (enterohemorrhagic E. coli), persistent diarrhea (enteroaggregative E. coli), and watery diarrhea of infants (enteropathogenic E. coli). This review discusses the current level of understanding of the pathogenesis of the diarrheagenic E. coli strains and describes how their pathogenic schemes underlie the clinical manifestations, diagnostic approach, and epidemiologic investigation of these important pathogens. PMID:9457432

Nataro, James P.; Kaper, James B.

1998-01-01

378

Effect of scavengers of oxygen-derived free radicals on mortality in endotoxin-challenged mice.  

PubMed

Oxygen-derived free radicals have been implicated as mediators of cellular injury in several model systems. Recently, a role for free radicals has been proposed in the mortality associated with Gram-negative bacterial sepsis. To determine if pretreatment with free radical scavengers can prevent endotoxin-induced mortality, mice rendered sensitive to endotoxin with actinomycin D were treated with either superoxide dismutase (SOD), N-acetylcysteine (NAC) or saline and were then challenged with a dose of endotoxin calculated to cause a mortality of greater than 80%. Mortality was assessed at 12-h intervals after challenge. Increased survival was seen in the SOD-treated group compared to the control group (p less than or equal to .05). In contrast, survival in mice treated with NAC, another potential scavenger, was not significantly different from the control group. These results support the hypothesis that superoxide and hydroxyl radicals contribute to mortality in Gram-negative bacterial sepsis. PMID:3042286

Broner, C W; Shenep, J L; Stidham, G L; Stokes, D C; Hildner, W K

1988-09-01

379

Mitochondrial DAMPs Induce Endotoxin Tolerance in Human Monocytes: An Observation in Patients with Myocardial Infarction  

PubMed Central

Monocyte exposure to mitochondrial Danger Associated Molecular Patterns (DAMPs), including mitochondrial DNA (mtDNA), induces a transient state in which these cells are refractory to further endotoxin stimulation. In this context, IRAK-M up-regulation and impaired p65 activity were observed. This phenomenon, termed endotoxin tolerance (ET), is characterized by decreased production of cytokines in response to the pro-inflammatory stimulus. We also show that monocytes isolated from patients with myocardial infarction (MI) exhibited high levels of circulating mtDNA, which correlated with ET status. Moreover, a significant incidence of infection was observed in those patients with a strong tolerant phenotype. The present data extend our current understanding of the implications of endotoxin tolerance. Furthermore, our data suggest that the levels of mitochondrial antigens in plasma, such as plasma mtDNA, should be useful as a marker of increased risk of susceptibility to nosocomial infections in MI and in other pathologies involving tissue damage. PMID:24797663

Hernández-Jiménez, Enrique; Moreno-González, Raúl; Toledano, Víctor; Fernández-Velasco, María; Vallejo-Cremades, Maria T.; Esteban-Burgos, Laura; de Diego, Rebeca Pérez; Llamas-Matias, Miguel A.; García-Arumi, Elena; Martí, Ramón; Boscá, Lisardo; Andreu, Antoni L.; López-Sendón, José Luis; López-Collazo, Eduardo

2014-01-01

380

Species-Specific Activation of TLR4 by Hypoacylated Endotoxins Governed by Residues 82 and 122 of MD-2  

PubMed Central

The Toll-like receptor 4/MD-2 receptor complex recognizes endotoxin, a Gram-negative bacterial cell envelope component. Recognition of the most potent hexaacylated form of endotoxin is mediated by the sixth acyl chain that protrudes from the MD-2 hydrophobic pocket and bridges TLR4/MD-2 to the neighboring TLR4 ectodomain, driving receptor dimerization via hydrophobic interactions. In hypoacylated endotoxins all acyl chains could be accommodated within the binding pocket of the human hMD-2. Nevertheless, tetra- and pentaacylated endotoxins activate the TLR4/MD-2 receptor of several species. We observed that amino acid residues 82 and 122, located at the entrance to the endotoxin binding site of MD-2, have major influence on the species-specific endotoxin recognition. We show that substitution of hMD-2 residue V82 with an amino acid residue with a bulkier hydrophobic side chain enables activation of TLR4/MD-2 by pentaacylated and tetraacylated endotoxins. Interaction of the lipid A phosphate group with the amino acid residue 122 of MD-2 facilitates the appropriate positioning of the hypoacylated endotoxin. Moreover, mouse TLR4 contributes to the agonistic effect of pentaacylated msbB endotoxin. We propose a molecular model that explains how the molecular differences between the murine or equine MD-2, which both have sufficiently large hydrophobic pockets to accommodate all five or four acyl chains, influence the positioning of endotoxin so that one of the acyl chains remains outside the pocket and enables hydrophobic interactions with TLR4, leading to receptor activation. PMID:25203747

Oblak, Alja; Jerala, Roman

2014-01-01

381

Biphasic Fermentation Is an Efficient Strategy for the Overproduction of ?-Endotoxin from Bacillus thuringiensis.  

PubMed

This study illustrates a biphasic solid-state fermentation (SSF) strategy for the overproduction of ?-endotoxin from Bacillus thuringiensis subsp. kurstaki (Btk) and also purification of ?-endotoxin from the solid-fermented medium. The fermentation strategy had two phases (biphasic); i.e., the first short phase was semisolid state (12 h), and the remaining long phase was strict SSF. To achieve the biphasic SSF, after 12 h (150 rpm, 37 °C) fermentation of the medium [Luria-Bertani (LB) supplemented with 30 % (w/v) raw soybean flour (phase I)], the supernatant in it was completely centrifuged out (1,000×g, 10 min) aseptically for harvesting the extracellular enzymes as by-product. The resultant wet solid matter without free-flowing liquid but with embedded Btk was incubated 60 h more (phase II) for enhancing ?-endotoxin production at static condition (37 °C). Coupled with this, ?-endotoxin was purified by the modified phase separation method, and its purity was physically confirmed by both staining and microscopic techniques. The maximum ?-endotoxin yield from solid medium (48 h) was 15.8 mg/mL (recovery was 55-59 %) LB-equivalent, while that of LB control (recovery was 95 %) was only 0.43 mg/mL (72 h), i.e., thus, in comparison, 36.74-fold more yield in solid medium obtained by 24 h less gestation period. The purified crystal proteins showed apparent molecular weights (MWs) of 45, 35, and 6 kDa on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Briefly, this unique study physically demonstrates how Btk ?-endotoxin is purified (95-99 % purity) from solid-fermented matter for the first time, coupled with its overproduction at the expense of only 21.5 % higher production cost. PMID:25410805

Jisha, Veloorvalappil Narayanan; Babysarojam Smitha, Robinson; Priji, Prakasan; Sajith, Sreedharan; Benjamin, Sailas

2014-11-20

382

Detection of endotoxins with the Limulus test in burned and unburned mice infected with different species of gram-negative bacteria.  

PubMed Central

The Limulus test detected endotoxins in the plasma of burned and unburned mice infected with different species of gram-negative bacteria produced different amounts of endotoxin in the plasma of infected mice. Plasma from mice given lethal infections showed very high concentrations of endotoxin. Low concentrations of endotoxin in the plasma were tolerated by mice but high concentrations were invariably fatal. A polyvalent pseudomonas vaccine reduced endotoxin in the plasma of mice given lethal infections of Pseudomonas aeruginosa. Images Plate 1 PMID:807621

Jones, R. J.; Roe, E. A.; Dyster, R. E.

1975-01-01

383

Modification of Selected Host-reactive Properties of Endotoxin by Treatment with Sodium Deoxycholate  

PubMed Central

Endotoxin dissociated into subunits by sodium deoxycholate treatment exhibited diminished capacity to kill chick embryos, protect mice against the lethal effects of infection with Salmonella typhi, evoke hemorrhagic necrosis in skin inoculated with epinephrine, prepare for and provoke the dermal Shwartzman reaction, and induce pyrogenic tolerance. Surfactant-treated material which had been allowed to reaggregate displayed activity equivalent to that of untreated material. These findings were consistent with the working hypothesis that a macromolecular complex of critical size is required in order for endotoxin to elicit its characteristic effects in the host. PMID:5726302

Tarmina, D. F.; Milner, K. C.; Ribi, E.; Rudbach, J. A.

1968-01-01

384

Development of a biological protocol for endotoxin detection using quartz crystal microbalance (QCM).  

PubMed

In this paper, a biological protocol for endotoxin detection has been developed and optimi