scholarly journals Construction of Escherichia coli Mutant with Decreased Endotoxic Activity by Modifying Lipid A Structure

Marine Drugs ◽  
2015 ◽  
Vol 13 (6) ◽  
pp. 3388-3406 ◽  
Author(s):  
Qiong Liu ◽  
Yanyan Li ◽  
Xinxin Zhao ◽  
Xue Yang ◽  
Qing Liu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Lipid A ◽  
Coli Mutant ◽  
Lipid A Structure ◽  
Endotoxic Activity

scholarly journals Biological Characterization of Endotoxins Released from Antibiotic-Treated Pseudomonas aeruginosa and Escherichia coli

1998 ◽  
Vol 42 (5) ◽  
pp. 1015-1021 ◽  
Author(s):  
Teruo Kirikae ◽  
Fumiko Kirikae ◽  
Shinji Saito ◽  
Kaoru Tominaga ◽  
Hirohi Tamura ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Lipid A ◽  
Biological Activities ◽  
Polymyxin B ◽  
Mitogen Activated Protein Kinase ◽  
No Production ◽  
Endotoxic Activity

ABSTRACT The supernatants taken from Pseudomonas aeruginosa andEscherichia coli cultures in human sera or chemically defined M9 medium in the presence of ceftazidime (CAZ) contained high levels of endotoxin, while those taken from the same cultures in the presence of imipenem (IPM) yielded a very low level of endotoxin. The biological activities of endotoxin in the supernatants were compared with those of phenol water-extracted lipopolysaccharide (LPS). The endotoxin released from the organisms as a result of CAZ treatment (CAZ-released endotoxin) contained a large amount of protein. The protein, however, lacked endotoxic activity, since the endotoxin did not show any in vivo toxic effects in LPS-hyporesponsive C3H/HeJ mice sensitized with d-(+)-galactosamine (GalN) or any activation of C3H/HeJ mouse macrophages in vitro. The activities of CAZ- and IPM-released endotoxin (as assessed by a chromogenicLimulus test) were fundamentally the same as those ofP. aeruginosa LPS, since their regression lines were parallel. The CAZ-released endotoxin was similar to purified LPS with respect to the following biological activities in LPS-responsive C3H/HeN mice and LPS-hyporesponsive C3H/HeJ mice: lethal toxicity in GalN-sensitized mice, in vitro induction of tumor necrosis factor- and NO production by macrophages, and mitogen-activated protein kinase activation in macrophages. The macrophage activation by CAZ-released endotoxin as well as LPS was mainly dependent on the presence of serum factor and CD14 antigen. Polymyxin B blocked the activity. These findings indicate that the endotoxic activity of CAZ-released endotoxin is due primarily to LPS (lipid A).

Construction of an Escherichia coli mutant producing monophosphoryl lipid A

2011 ◽  
Vol 33 (5) ◽  
pp. 1013-1019 ◽  
Author(s):  
Jiuzhou Chen ◽  
Guanjun Tao ◽  
Xiaoyuan Wang
Keyword(s):  
Escherichia Coli ◽  
Lipid A ◽  
Coli Mutant ◽  
Monophosphoryl Lipid A ◽  
Monophosphoryl Lipid

scholarly journals Construction and Characterization of an Escherichia coli Mutant Producing Kdo2-Lipid A

Marine Drugs ◽  
2014 ◽  
Vol 12 (3) ◽  
pp. 1495-1511 ◽  
Author(s):  
Jianli Wang ◽  
Wenjian Ma ◽  
Zhou Wang ◽  
Ye Li ◽  
Xiaoyuan Wang
Keyword(s):  
Escherichia Coli ◽  
Lipid A ◽  
Coli Mutant

scholarly journals A novel plasmid-encoded mcr-4.3 gene in a colistin-resistant Acinetobacter baumannii clinical strain

2019 ◽  
Vol 75 (1) ◽  
pp. 60-64 ◽  
Author(s):  
Natacha Martins-Sorenson ◽  
Erik Snesrud ◽  
Danilo Elias Xavier ◽  
Luciana Camila Cacci ◽  
Anthony T Iavarone ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Acinetobacter Baumannii ◽  
Molecular Mechanism ◽  
Resistance Genes ◽  
Lipid A ◽  
Clinical Strain ◽  
Colistin Resistance ◽  
Short Read ◽  
E Coli ◽  
Lipid A Structure

Abstract Objectives To identify the molecular mechanism of colistin resistance in an MDR Acinetobacter baumannii clinical strain isolated in 2008 from a meningitis case in Brazil. Methods Long- and short-read WGS was used to identify colistin resistance genes in A. baumannii strain 597A with a colistin MIC of 64 mg/L. MS was used to analyse lipid A content. mcr was cloned into pET-26b (+) and transformed into Escherichia coli BL21(λDE3)pLysS for analysis. Results A novel plasmid (pAb-MCR4.3) harbouring mcr-4.3 within a Tn3-like transposon was identified. The A. baumannii 597A lipid A MS spectra showed a main molecular ion peak at m/z=2034, which indicated the addition of phosphoethanolamine to the lipid A structure. E. coli BL21 transformed with pET-26b-mcr-4.3 gained colistin resistance with a colistin MIC of 8 mg/L. Conclusions Colistin resistance in A. baumannii 597A was correlated with the presence of a novel plasmid-encoded mcr-4.3 gene.

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