scholarly journals Identification and characterization of the caiF gene encoding a potential transcriptional activator of carnitine metabolism in Escherichia coli.

1996 ◽  
Vol 178 (5) ◽  
pp. 1248-1257 ◽  
Author(s):  
K Eichler ◽  
A Buchet ◽  
R Lemke ◽  
H P Kleber ◽  
M A Mandrand-Berthelot
Keyword(s):  
Escherichia Coli ◽  
Transcriptional Activator ◽  
Gene Encoding ◽  
Carnitine Metabolism ◽  
Identification And Characterization

scholarly journals Identification and Characterization of Shiga Toxin Type 2 Variants in Escherichia coli Isolates from Animals, Food, and Humans

2008 ◽  
Vol 74 (18) ◽  
pp. 5645-5652 ◽  
Author(s):  
Jie Zheng ◽  
Shenghui Cui ◽  
Louise D. Teel ◽  
Shaohua Zhao ◽  
Ruby Singh ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Gene Encoding ◽  
Intestinal Mucus ◽  
One Step ◽  
A Subunit ◽  
Pcr Method ◽  
Identification And Characterization

ABSTRACT There is considerable heterogeneity among the Shiga toxin type 2 (Stx2) toxins elaborated by Shiga toxin-producing Escherichia coli (STEC). One such Stx2 variant, the Stx2d mucus-activatable toxin (Stx2dact), is rendered more toxic by the action of elastase present in intestinal mucus, which cleaves the last two amino acids of the A2 portion of the toxin A subunit. We screened 153 STEC isolates from food, animals, and humans for the gene encoding Stx2dact by using a novel one-step PCR procedure. This method targeted the region of stx 2dact that encodes the elastase recognition site. The presence of stx 2dact was confirmed by DNA sequencing of the complete toxin genes. Seven STEC isolates from cows (four isolates), meat (two isolates), and a human (one isolate) that carried the putative stx 2dact gene were identified; all were eae negative, and none was the O157:H7 serotype. Three of the isolates (CVM9322, CVM9557, and CVM9584) also carried stx 1, two (P1332 and P1334) carried stx 1 and stx 2c, and one (CL-15) carried stx 2c. One isolate, P1130, harbored only stx 2dact. The Vero cell cytotoxicities of supernatants from P1130 and stx 1 deletion mutants of CVM9322, CVM9557, and CVM9584 were increased 13- to 30-fold after treatment with porcine elastase. Thus, Stx2dact-producing strains, as detected by our one-step PCR method, can be isolated not only from humans, as previously documented, but also from food and animals. The latter finding has important public health implications based on a recent report from Europe of a link between disease severity and infection with STEC isolates that produce Stx2dact.

Molecular characterization of three mutations in katG affecting the activity of hydroperoxidase I of Escherichia coli

1990 ◽  
Vol 68 (7-8) ◽  
pp. 1037-1044 ◽  
Author(s):  
Peter C. Loewen ◽  
Jacek Switala ◽  
Mark Smolenski ◽  
Barbara L. Triggs-Raine
Keyword(s):  
Escherichia Coli ◽  
Specific Activity ◽  
Polymerase Chain Reaction Amplification ◽  
Protein A ◽  
Wild Type ◽  
Wild Type Enzyme ◽  
Gene Encoding ◽  
Reaction Amplification ◽  
Mutant Genes

Hydroperoxidase I (HPI) of Escherichia coli is a bifunctional enzyme exhibiting both catalase and peroxidase activities. Mutants lacking appreciable HPI have been generated using nitrosoguanidine and the gene encoding HPI, katG, has been cloned from three of these mutants using either classical probing methods or polymerase chain reaction amplification. The mutant genes were sequenced and the changes from wild-type sequence identified. Two mutants contained G to A changes in the coding strand, resulting in glycine to aspartate changes at residues 119 (katG15) and 314 (katG16) in the deduced amino acid sequence of the protein. A third mutant contained a C to T change resulting in a leucine to phenylalanine change at residue 139 (katG14). The Phe139-, Asp119-, and Asp314-containing mutants exhibited 13, < 1, and 18%, respectively, of the wild-type catalase specific activity and 43, 4, and 45% of the wild-type peroxidase specific activity. All mutant enzymes bound less protoheme IX than the wild-type enzyme. The sensitivities of the mutant enzymes to the inhibitors hydroxylamine, azide, and cyanide and the activators imidazole and Tris were similar to those of the wild-type enzyme. The mutant enzymes were more sensitive to high temperature and to β-mercaptoethanol than the wild-type enzyme. The pH profiles of the mutant catalases were unchanged from the wild-type enzyme.Key words: catalase, hydroperoxidase I, mutants, sequence analysis.

scholarly journals Identification and characterization of YLR328W, theSaccharomyces cerevisiaestructural gene encoding NMN adenylyltransferase. Expression and characterization of the recombinant enzyme

FEBS Letters ◽  
1999 ◽  
Vol 455 (1-2) ◽  
pp. 13-17 ◽  
Author(s):  
Monica Emanuelli ◽  
Francesco Carnevali ◽  
Maria Lorenzi ◽  
Nadia Raffaelli ◽  
Adolfo Amici ◽  
...  
Keyword(s):  
Recombinant Enzyme ◽  
Gene Encoding ◽  
Identification And Characterization

scholarly journals Isolation and characterization of escherichia coli in ready-to-eat foods vended in Islamic University, Kushtia

1970 ◽  
Vol 18 ◽  
pp. 99-103 ◽  
Author(s):  
S Biswas ◽  
MAK Parvez ◽  
M Shafiquzzaman ◽  
S Nahar ◽  
MN Rahman
Keyword(s):  
Escherichia Coli ◽  
Pattern Analysis ◽  
University Campus ◽  
Rflp Pattern ◽  
E Coli ◽  
Fish Meat ◽  
Isolation And Characterization ◽  
Food Borne ◽  
Identification And Characterization

Context: Escherichia coli is shed in the feces of warm blooded animals and humans and thus potential for public health. Detection and characterization of E. coli in the ready-to-eat (RTE) foods concerns due to their presence indicates fecal contamination of the food.   Objective: To identify, characterize and RFLP pattern analysis of E. coli isolated from RTE foods vended in Islamic University campus, Kushtia.   Materials and Methods: Fifty samples from four types of consumed foods in six student halls of residence, some temporary restaurants of Islamic University, Kushtia were assessed for bacterial contamination by standard methods. Identification and characterization of E. coli isolates were performed using IMViC tests. Genomic DNA was used to perform RFLP pattern analysis.   Results: Thirty seven out of 50 (74%) examined samples of RTE foods had E. coli contamination. The highest number of E. coli was isolated from vegetable oriented RTE foods (90.90%) and fish, meat and cereals samples were also significantly E. coli positive. RFLP profiling of two E. coli isolates were observed.   Conclusion: The results of this study provide evidence that some RTE foods had unsatisfactory levels of contamination with E. coli. Thus street vended RTE food could be important potential vehicles for food-borne diseases. Molecular characterization may be exploited to identify food borne pathogen among different species.  Keywords: Ready-to-eat foods; Escherichia coli; RFLP pattern DOI: http://dx.doi.org/10.3329/jbs.v18i0.8783 JBS 2010; 18(0): 99-103

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