An Escherichia coli mutant thermosensitive in the B subunit of DNA gyrase: Effect on the structure and replication of the colicin E1 plasmid in vitro

1981 ◽  
Vol 181 (1) ◽  
pp. 52-56 ◽  
Author(s):  
Elisha Orr ◽  
Walter L. Staudenbauer
Keyword(s):  
Escherichia Coli ◽  
Dna Gyrase ◽  
B Subunit ◽  
Coli Mutant ◽  
Colicin E1

scholarly journals Assembly of the B subunit pentamer of Escherichia coli heat-labile enterotoxin. Kinetics and molecular basis of rate-limiting steps in vitro.

1996 ◽  
Vol 271 (43) ◽  
pp. 27188
Author(s):  
Lloyd W. Ruddock ◽  
Jeremy J.F. Coen ◽  
Caroline Cheesman ◽  
Robert B. Freedman ◽  
Timothy R. Hirst
Keyword(s):  
Escherichia Coli ◽  
Molecular Basis ◽  
B Subunit ◽  
Heat Labile ◽  
Rate Limiting

scholarly journals Differential behaviors of Staphylococcus aureus and Escherichia coli type II DNA topoisomerases.

1996 ◽  
Vol 40 (12) ◽  
pp. 2714-2720 ◽  
Author(s):  
F Blanche ◽  
B Cameron ◽  
F X Bernard ◽  
L Maton ◽  
B Manse ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Strong Support ◽  
Dna Gyrase ◽  
Dna Supercoiling ◽  
Type Ii ◽  
Topoisomerase Iv ◽  
E Coli ◽  
Dna Relaxation

Staphylococcus aureus gyrA and gyrB genes encoding DNA gyrase subunits were cloned and coexpressed in Escherichia coli under the control of the T7 promoter-T7 RNA polymerase system, leading to soluble gyrase which was purified to homogeneity. Purified gyrase was catalytically indistinguishable from the gyrase purified from S. aureus and did not contain detectable amounts of topoisomerases from the E. coli host. Topoisomerase IV subunits GrlA and GrlB from S. aureus were also expressed in E. coli and were separately purified to apparent homogeneity. Topoisomerase IV, which was reconstituted by mixing equimolar amounts of GrlA and GrlB, had both ATP-dependent decatenation and DNA relaxation activities in vitro. This enzyme was more sensitive than gyrase to inhibition by typical fluoroquinolone antimicrobial agents such as ciprofloxacin or sparfloxacin, adding strong support to genetic studies which indicate that topoisomerase IV is the primary target of fluoroquinolones in S. aureus. The results obtained with ofloxacin suggest that this fluoroquinolone could also primarily target gyrase. No cleavable complex could be detected with S. aureus gyrase upon incubation with ciprofloxacin or sparfloxacin at concentrations which fully inhibit DNA supercoiling. This suggests that these drugs do not stabilize the open DNA-gyrase complex, at least under standard in vitro incubation conditions, but are more likely to interfere primarily with the DNA breakage step, contrary to what has been reported with E. coli gyrase. Both S. aureus gyrase-catalyzed DNA supercoiling and S. aureus topoisomerase IV-catalyzed decatenation were dramatically stimulated by potassium glutamate or aspartate (500- and 50-fold by 700 and 350 mM glutamate, respectively), whereas topoisomerase IV-dependent DNA relaxation was inhibited 3-fold by 350 mM glutamate. The relevance of the effect of dicarboxylic amino acids on the activities of type II topoisomerases is discussed with regard to the intracellular osmolite composition of S. aureus.

scholarly journals In vivo and in vitro adjuvant activities of the B subunit of Type IIb heat-labile enterotoxin (LT-IIb-B5) from Escherichia coli

Vaccine ◽  
2009 ◽  
Vol 27 (32) ◽  
pp. 4302-4308 ◽  
Author(s):  
Shuang Liang ◽  
Kavita B. Hosur ◽  
Hesham F. Nawar ◽  
Michael W. Russell ◽  
Terry D. Connell ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
B Subunit ◽  
Heat Labile

DNA breakage by Escherichia coli DNA gyrase in vitro and in vivo

1986 ◽  
Vol 14 (2) ◽  
pp. 493-496 ◽  
Author(s):  
L. MARK FISHER ◽  
HEATHER A. BAROT ◽  
MARTIN E. CULLEN ◽  
CHRISTOPHER S. J. HULTON
Keyword(s):  
Escherichia Coli ◽  
Dna Gyrase ◽  
Dna Breakage

scholarly journals Dietary Inclusion of Colicin E1 Is Effective in Preventing Postweaning Diarrhea Caused by F18-Positive Escherichia coli in Pigs

2007 ◽  
Vol 51 (11) ◽  
pp. 3830-3835 ◽  
Author(s):  
S. A. Cutler ◽  
S. M. Lonergan ◽  
N. Cornick ◽  
A. K. Johnson ◽  
C. H. Stahl
Keyword(s):  
Escherichia Coli ◽  
Tumor Necrosis ◽  
E Coli ◽  
Colicin E1 ◽  
Young Pigs ◽  
Weaning Pigs ◽  
Conventional Antibiotics ◽  
Postweaning Diarrhea ◽  
Necrosis Factor

ABSTRACT With worldwide concern over the use of antibiotics in animal agriculture and their contribution to the spread of antibiotic resistance, alternatives to conventional antibiotics are needed. Previous research in our laboratories has shown that colicin E1 is effective against some Escherichia coli strains responsible for postweaning diarrhea (PWD) in vitro. In this study we examined the efficacy of the dietary inclusion of colicin E1 in preventing experimentally induced PWD caused by F18-positive enterotoxigenic E. coli in young pigs. Twenty-four weaned pigs (23 days of age), identified by genotyping to be susceptible to F18-positive E. coli infections, were individually housed and fed diets containing 0, 11, or 16.5 mg colicin E1/kg diet. Two days after the start of the trial, all animals were orally inoculated with 1 × 109 CFU of each of two F18-positive E. coli strains isolated from pigs with PWD. The dietary inclusion of colicin E1 decreased the incidence and severity of PWD caused by F18-positive enterotoxigenic E. coli and improved the growth performance of the piglets. Additionally, the reduced incidence of PWD due to dietary colicin E1, lowered the levels of expression of the genes for interleukin 1β and tumor necrosis factor beta in ileal tissues from these animals. The dietary inclusion of colicin E1 may be an effective alternative to conventional antibiotics in the diets of weaning pigs for the prevention of PWD caused by F18-positive enterotoxigenic E. coli.

scholarly journals Synthesis and Biological Evaluation of New Pyridothienopyrimidine Derivatives as Antibacterial Agents and Escherichia coli Topoisomerase II Inhibitors

Antibiotics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 695
Author(s):  
Eman M. Mohi El-Deen ◽  
Eman A. Abd El-Meguid ◽  
Eman A. Karam ◽  
Eman S. Nossier ◽  
Marwa F. Ahmed
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Topoisomerase Ii ◽  
Antibacterial Agents ◽  
Dna Gyrase ◽  
Structural Features ◽  
Biological Evaluation ◽  
Topoisomerase Iv ◽  
Gram Negative

The growing resistance of bacteria to many antibiotics that have been in use for several decades has generated the need to discover new antibacterial agents with structural features qualifying them to overcome the resistance mechanisms. Thus, novel pyridothienopyrimidine derivatives (2a,b–a,b) were synthesized by a series of various reactions, starting with 3-aminothieno[2,3-b]pyridine-2-carboxamides (1a,b). Condensation of compounds 1a,b with cyclohexanone gave 1’H-spiro[cyclohexane-1,2’-pyrido[3’,2’:4,5]thieno[3,2-d]pyrimidin]-4’(3’H)-ones (2a,b), which in turn were utilized to afford the target 4-substituted derivatives (3a,b–8a,b). In vitro antibacterial activity evaluations of all the new compounds (2a,b–8a,b) were performed against six strains of Gram-negative and Gram-positive bacteria. The target compounds showed significant antibacterial activity, especially against Gram-negative strains. Moreover, the compounds (2a,b; 3a,b; 4a,b; and 5a,b) that exhibited potent activity against Escherichia coli were selected to screen their inhibitory activity against Escherichia coli topoisomerase II (DNA gyrase and topoisomerase IV) enzymes. Compounds 4a and 4b showed potent dual inhibition of the two enzymes with IC50 values of 3.44 µΜ and 5.77 µΜ against DNA gyrase and 14.46 µΜ and 14.89 µΜ against topoisomerase IV, respectively. In addition, docking studies were carried out to give insight into the binding mode of the tested compounds within the E. coli DNA gyrase B active site compared with novobiocin.

scholarly journals Colicin Concentrations Inhibit Growth of Escherichia coli O157:H7 In Vitro†

2004 ◽  
Vol 67 (11) ◽  
pp. 2603-2607 ◽  
Author(s):  
T. R. CALLAWAY ◽  
C. H. STAHL ◽  
T. S. EDRINGTON ◽  
K. J. GENOVESE ◽  
L. M. LINCOLN ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogen ◽  
Escherichia Coli O157 ◽  
Antimicrobial Proteins ◽  
E Coli ◽  
Colicin E1 ◽  
Human Illness ◽  
Food Animals ◽  
Environmentally Sound

Escherichia coli O157:H7 is a virulent foodborne pathogen that causes severe human illness and inhabits the intestinal tract of food animals. Colicins are antimicrobial proteins produced by E. coli strains that inhibit or kill other E. coli. In the present study, the efficacy of three pore-forming colicins (E1, N, and A) were quantified in vitro against E. coli O157:H7 strains 86-24 and 933. Colicins E1 and N reduced the growth of E. coli O157:H7 strains, but the efficacy of each colicin varied among strains. Colicin E1 was more effective against both strains of E. coli O157:H7 than colicins A and N and reduced (P < 0.05) populations of E. coli O157:H7 at concentrations <0.1 μg/ml. These potent antimicrobial proteins may potentially provide an effective and environmentally sound preharvest strategy to reduce E. coli O157:H7 in food animals.

Crystal engineering: deletion mutagenesis of the 24 kDa fragment of the DNA gyrase B subunit from Staphylococcus aureus

1999 ◽  
Vol 55 (9) ◽  
pp. 1626-1629 ◽  
Author(s):  
Glenn E. Dale ◽  
Dirk Kostrewa ◽  
Bernard Gsell ◽  
Martin Stieger ◽  
Allan D'Arcy
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Crystal Engineering ◽  
Dna Gyrase ◽  
Wild Type ◽  
Scanning Calorimetry ◽  
Mutant Proteins ◽  
B Subunit ◽  
Deletion Mutagenesis ◽  
Single Well

The 24 kDa fragment of DNA gyrase B from Staphylococcus aureus was expressed in Escherichia coli and purified for crystallization. Crystals of the wild-type protein grew in the presence of cyclothialidine but proved difficult to reproduce. In order to improve the crystallization, the flexible regions of the protein were deleted by mutagenesis. The mutant proteins were analyzed by differential scanning calorimetry and the most stable mutants produced crystals. It was possible to reproducibly grow in the microbatch system single well defined crystals which belonged to the space group C2 and diffracted isotropically to approximately 2 Å resolution.

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