〈85〉 Bacterial Endotoxins Test

2021 ◽  
Keyword(s):  
Bacterial Endotoxins

A New Fluorogenic Substrate Method for Assay of Bacterial Endotoxins Using Limulus Hemocyte Lysate

1979 ◽  
Author(s):  
T Harada ◽  
M Ohki ◽  
M Niwa ◽  
S Iwanaga
Keyword(s):  
Antithrombin Iii ◽  
Assay Method ◽  
Sensitive Assay ◽  
Fluorogenic Substrate ◽  
Toxin Concentration ◽  
Amidase Activity ◽  
E Coli ◽  
Bacterial Endotoxins ◽  
Plasmin Inhibitor ◽  
Limulus Test

Limulus hemocyte lysate contains a proclotting enzyme, which is transformed to the active clotting enzyme in the presence of gram-negative bacterial endotoxins. The clotting enzyme coagulates a clottable protein, named coagulogen, contained also in the lysate. This gelation reaction of the lysate, named Limulus test, has been widely employed as a simple and very sensitive assay method for endotoxins. We developed a new fluorogenic substrate, Boc-Leu-Gly-Arg-4-methylcoumarin amide, for Limulus clotting enzyme and established an enzymatic assay method for endotoxins, using the substrate. Because the endotoxin mediates the activation of proclotting enzyme in the lysate, the measurement of amidase activity could be applicable for quantitation of the endotoxins. In fact, the amidase activity determined fluorometrically increased by increasing concentration of E. coli 0111: B4 endotoxin added to the lysate, and a linear relationship between the toxin concentration and the activity was observed in the range of 5X10-6to 5xl0-2 µg endotoxin. The method was a fifty times more sensitive than that of the Limulus test and was very reproducible. However, the method was not directly applicable for the assay of endotoxins in circulating blood, as the amidase activity was strongly inhibited by antithrombin III and α2-plasmin inhibitor. Thus, some pretreatment with heat or chloroform on plasma samples before the assay was required.

Endothelial expression of selectins during endotoxin preconditioning

2000 ◽  
Vol 279 (6) ◽  
pp. R2015-R2021 ◽  
Author(s):  
Philippe Bauer ◽  
Tomas Welbourne ◽  
Takeharu Shigematsu ◽  
Janice Russell ◽  
D. Neil Granger
Keyword(s):  
Nitric Oxide ◽  
Similar Reduction ◽  
Antibody Technique ◽  
Immunodeficient Mice ◽  
Lps Challenge ◽  
Tissue Resistance ◽  
Bacterial Endotoxins ◽  
Circulating Lymphocytes ◽  
Lps Preconditioning ◽  
Oxide Synthase

Although bacterial endotoxins [lipopolysaccharide (LPS)] can confer tissue resistance to subsequent inflammatory insults, the mechanisms that underlie this LPS-preconditioning (LPS-PC) response remain poorly defined. The dual-radiolabeled monoclonal antibody technique was used to examine whether LPS-PC alters the upregulation (protein) of E- and P-selectins after subsequent LPS challenge. In the gut of wild-type (C57BL/6J) mice, LPS-PC was associated with a reduction in E- (66%) and P-selectin (33%) expression. A similar reduction in E-selectin expression was observed in mutant mice that were genetically deficient in either the endothelial or inducible isoform of nitric oxide synthase or that overexpressed the human gene for Cu/Zn superoxide dismutase. Severe combined immunodeficient mice, genetically devoid of lymphocytes, did exhibit partial inhibition of the LPS-PC response. We conclude that 1) LPS-PC can be demonstrated for E- and P-selectins in some vascular beds (e.g., gut), 2) the mechanism(s) underlying this blunted selectin response does not include a major role for either nitric oxide and superoxide, and 3) circulating lymphocytes may contribute to the LPS-PC response.

scholarly journals Covalently immobilized chemically modified lysozyme as a sorbent for bacterial endotoxins (lipopolysaccharides)

2019 ◽  
Vol 24 ◽  
pp. e00381 ◽  
Author(s):  
Pavel A. Levashov ◽  
Darya A. Matolygina ◽  
Oxana A. Dmitrieva ◽  
Ekaterina D. Ovchinnikova ◽  
Irina Yu. Adamova ◽  
...  
Keyword(s):  
Chemically Modified ◽  
Bacterial Endotoxins

scholarly journals Development of a new trend conjugate vaccine for the prevention of Klebsiella pneumoniae

2012 ◽  
Vol 4 (1) ◽  
pp. 33 ◽  
Author(s):  
Tarek A. Ahmad ◽  
Medhat Haroun ◽  
Ahmed A. Hussein ◽  
El Sayed H. El Ashry ◽  
Laila H. El-Sayed
Keyword(s):  
Klebsiella Pneumoniae ◽  
Respiratory Diseases ◽  
Capsular Polysaccharide ◽  
Outer Membrane Proteins ◽  
Immunological Methods ◽  
Easy Method ◽  
O Antigen ◽  
Bacterial Endotoxins ◽  
Tract Infections ◽  
Limited Spectrum

<em>Klebsiella pneumoniae</em> is a major cause of nosocomial pneumonia, septicemia and urinary tract infections, especially in newborns, blood cancer patients, and other immunocompromised candidates. The control of <em>K. pneumoniae</em> is a complicated issue due to its tight pathogenesis. Immuno-prophylactic preparations, especially those directed toward the <em>bacterium</em> O-antigen, showed to be the most successful way to prevent the infection incidence. However, all previously proposed preparations were either of limited spectrum or non-maternal, and hence not targeting the main <em>Klebsiella</em> patients. Moreover, all preparations were directed only to prevent the respiratory diseases due to that pathogen. This article addresses the development of a method originally used to purify the non-capsular bacterial- endotoxins, as a new and easy method for vaccine production against <em>K. pneumoniae</em>. The application of this method was preceded by a biotechnological control of capsular polysaccharide production in <em>K. pneumoniae</em>. The new produced natural conjugate between the bacterial O-antigen and its outer membrane proteins was evaluated by physicochemical and immunological methods to investigate its purity, integrity, safety and immunogenicity. It showed to be pure, stable, safe for use, and able to elicit a protective immunoglobulin titer against different <em>Klebsiella</em> infections. This immune-response proved to be transferable to the offspring of the vaccinated experimental rabbits via placenta.

scholarly journals Biofilm Growth Increases Phosphorylcholine Content and Decreases Potency of Nontypeable Haemophilus influenzae Endotoxins

2006 ◽  
Vol 74 (3) ◽  
pp. 1828-1836 ◽  
Author(s):  
Shayla West-Barnette ◽  
Andrea Rockel ◽  
W. Edward Swords
Keyword(s):  
Haemophilus Influenzae ◽  
Inflammatory Responses ◽  
Opportunistic Pathogen ◽  
Host Responses ◽  
Toll Like Receptor ◽  
Nontypeable Haemophilus Influenzae ◽  
Toll Like Receptor 4 ◽  
Biofilm Growth ◽  
Bacterial Endotoxins ◽  
Cell Layers

ABSTRACT Nontypeable Haemophilus influenzae (NTHI) is a common respiratory commensal and opportunistic pathogen. NTHI is normally contained within the airways by host innate defenses that include recognition of bacterial endotoxins by Toll-like receptor 4 (TLR4). NTHI produces lipooligosaccharide (LOS) endotoxins which lack polymeric O side chains and which may contain host glycolipids. We recently showed that NTHI biofilms contain variants with sialylated LOS glycoforms that are essential to biofilm formation. In this study, we show that NTHI forms biofilms on epithelial cell layers. Confocal analysis revealed that sialylated variants were distributed throughout the biofilm, while variants expressing phosphorylcholine (PCho) were found within the biofilm. Consistent with this observation, PCho content of LOS purified from NTHI biofilms was increased compared to LOS from planktonic cultures. Hypothesizing that the observed changes in endotoxin composition could affect bioactivity, we compared inflammatory responses to NTHI LOS purified from biofilm and planktonic cultures. Our results show that endotoxins from biofilms induced weaker host innate responses. While we observed a minimal effect of sialylation on LOS bioactivity, there was a significant decrease in bioactivity associated with PCho substitutions. We thus conclude that biofilm growth increases the proportion of PCho+ variants in an NTHI population, resulting in a net decrease in LOS bioactivity. Thus, in addition to their well-documented resistance phenotypes, our data show that biofilm communities of NTHI bacteria contain variants that evoke less potent host responses.

Bacterial Endotoxins in the Environment

Nature ◽  
1973 ◽  
Vol 244 (5410) ◽  
pp. 49-51 ◽  
Author(s):  
N. R. DI LUZIO ◽  
T. J. FRIEDMANN
Keyword(s):  
Bacterial Endotoxins

scholarly journals SIMILARITY OF HOST RESPONSES ELICITED BY POLYSACCHARIDES OF ANIMAL AND PLANT ORIGIN AND BY BACTERIAL ENDOTOXINS

1957 ◽  
Vol 106 (1) ◽  
pp. 77-97 ◽  
Author(s):  
Maurice Landy ◽  
Murray J. Shear ◽  
Keyword(s):  
Host Responses ◽  
Mouse Tissue ◽  
Rabbit Skin ◽  
Biological Phenomena ◽  
Hemorrhagic Necrosis ◽  
Bacterial Endotoxins ◽  
Shwartzman Reaction ◽  
Sarcoma 37 ◽  
Kidney Liver ◽  
Plant Sources

Ten polysaccharides, isolated from various animal and plant sources, were selected for comparison with 2 bacterial polysaccharides, typical of Gram-negative endotoxins. The tissue sources were: mouse (kidney, liver, lung, stomach, Sarcoma 37, and Carcinoma 241-6); rabbit skin and chick embryo skin; and tangerine and Bryonia root. The bacterial endotoxins were those of S. typhosa and Serr. marcescens. Their relative potency was determined in inducing the following host effects: fever, tolerance to pyrogenic action, leucocytic changes, the Shwartzman reaction, damage to Sarcoma 37, dermal hemorrhagic-necrosis by epinephrine, enhancement of antibody production, and lethality. Some of the polysaccharides were consistently active in all the host reactions studied; except for pyrogenic activity at high dosage, the other polysaccharides were consistently negative throughout. The mouse tissue polysaccharides elicited all the effects studied; in some instances their potency approached those of the bacterial polysaccharides. It is pointed out that elicitation of the above array of biological phenomena, hitherto considered characteristic of bacterial endotoxins, can be obtained with polysaccharides from animal and plant tissues.

scholarly journals Peptide–perylene diimide functionalized magnetic nano-platforms for fluorescence turn-on detection and clearance of bacterial lipopolysaccharides

2014 ◽  
Vol 50 (47) ◽  
pp. 6200-6203 ◽  
Author(s):  
Fang Liu ◽  
Jing Mu ◽  
Xiangyang Wu ◽  
Surajit Bhattacharjya ◽  
Edwin Kok Lee Yeow ◽  
...  
Keyword(s):  
Perylene Diimide ◽  
Sensitive Detection ◽  
Turn On ◽  
Dual Functional ◽  
Bacterial Endotoxins ◽  
Rapid Clearance ◽  
Functional Peptide ◽  
Bacterial Lipopolysaccharides ◽  
Fluorescence Turn On

A simple and novel dual-functional peptide magnetic nanoplatform has been successfully designed for sensitive detection and rapid clearance of bacterial endotoxins.

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