scholarly journals Redox cycling amplified electrochemical detection of DNA hybridization: Application to pathogen E. coli bacterial RNA

2011 ◽  
Vol 689 (1) ◽  
pp. 29-33 ◽  
Author(s):  
Anne Walter ◽  
Jie Wu ◽  
Gerd-Uwe Flechsig ◽  
David A. Haake ◽  
Joseph Wang
Keyword(s):  
Electrochemical Detection ◽  
Dna Hybridization ◽  
Redox Cycling ◽  
E Coli ◽  
Bacterial Rna

Electrochemical detection of DNA hybridization using methylene blue and electro-deposited zirconia thin films on gold electrodes

2004 ◽  
Vol 510 (2) ◽  
pp. 163-168 ◽  
Author(s):  
Ningning Zhu ◽  
Aiping Zhang ◽  
Qingjiang Wang ◽  
Pingang He ◽  
Yuzhi Fang
Keyword(s):  
Thin Films ◽  
Methylene Blue ◽  
Electrochemical Detection ◽  
Dna Hybridization ◽  
Gold Electrodes

scholarly journals Antimicrobial-Resistant Enteric Bacteria from Dairy Cattle

2006 ◽  
Vol 73 (1) ◽  
pp. 156-163 ◽  
Author(s):  
Ashish A. Sawant ◽  
Narasimha V. Hegde ◽  
Beth A. Straley ◽  
Sarah C. Donaldson ◽  
Brenda C. Love ◽  
...  
Keyword(s):  
Dairy Cattle ◽  
Dna Hybridization ◽  
Bacterial Species ◽  
Dairy Herd ◽  
Enteric Bacteria ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
E Coli ◽  
Predominant Species ◽  
Lactating Dairy Cattle

ABSTRACT A study was conducted to understand the descriptive and molecular epidemiology of antimicrobial-resistant gram-negative enteric bacteria in the feces of healthy lactating dairy cattle. Gram-negative enteric bacteria resistant to ampicillin, florfenicol, spectinomycin, and tetracycline were isolated from the feces of 35, 8, 5, and 42% of 213 lactating cattle on 74, 39, 9, 26, and 82% of 23 farms surveyed, respectively. Antimicrobial-resistant gram-negative bacteria accounted for 5 (florfenicol) to 14% (tetracycline) of total gram-negative enteric microflora. Nine bacterial species were isolated, of which Escherichia coli (87%) was the most predominant species. MICs showing reduced susceptibility to ampicillin, ceftiofur, chloramphenicol, florfenicol, spectinomycin, streptomycin, and tetracycline were observed in E. coli isolates. Isolates exhibited resistance to ampicillin (48%), ceftiofur (11%), chloramphenicol (20%), florfenicol (78%), spectinomycin (18%), and tetracycline (93%). Multidrug resistance (≥3 to 6 antimicrobials) was seen in 40% of E. coli isolates from healthy lactating cattle. Of 113 tetracycline-resistant E. coli isolates, tet(B) was the predominant resistance determinant and was detected in 93% of isolates, while the remaining 7% isolates carried the tet(A) determinant. DNA-DNA hybridization assays revealed that tet determinants were located on the chromosome. Pulsed-field gel electrophoresis revealed that tetracycline-resistant E. coli isolates (n = 99 isolates) belonged to 60 subtypes, which is suggestive of a highly diverse population of tetracycline-resistant organisms. On most occasions, E. coli subtypes, although shared between cows within the herd, were confined mostly to a dairy herd. The findings of this study suggest that commensal enteric E. coli from healthy lactating cattle can be an important reservoir for tetracycline and perhaps other antimicrobial resistance determinants.

scholarly journals T7 phage factor required for managing RpoS inEscherichia coli

2018 ◽  
Vol 115 (23) ◽  
pp. E5353-E5362 ◽  
Author(s):  
Aline Tabib-Salazar ◽  
Bing Liu ◽  
Declan Barker ◽  
Lynn Burchell ◽  
Udi Qimron ◽  
...  
Keyword(s):  
Stationary Phase ◽  
Stationary Phases ◽  
Inescherichia Coli ◽  
E Coli ◽  
Bacterial Transcription ◽  
Bacterial Rna ◽  
Predominant Form ◽  
Phage Development ◽  
T7 Phage

T7 development inEscherichia colirequires the inhibition of the housekeeping form of the bacterial RNA polymerase (RNAP), Eσ70, by two T7 proteins: Gp2 and Gp5.7. Although the biological role of Gp2 is well understood, that of Gp5.7 remains to be fully deciphered. Here, we present results from functional and structural analyses to reveal that Gp5.7 primarily serves to inhibit EσS, the predominant form of the RNAP in the stationary phase of growth, which accumulates in exponentially growingE. colias a consequence of the buildup of guanosine pentaphosphate [(p)ppGpp] during T7 development. We further demonstrate a requirement of Gp5.7 for T7 development inE. colicells in the stationary phase of growth. Our finding represents a paradigm for how some lytic phages have evolved distinct mechanisms to inhibit the bacterial transcription machinery to facilitate phage development in bacteria in the exponential and stationary phases of growth.

Capture and Electrochemical Detection of Pathogenic E. coli

2021 ◽  
Vol MA2021-02 (55) ◽  
pp. 1596-1596
Author(s):  
Ariel L Furst
Keyword(s):  
Electrochemical Detection ◽  
E Coli

Etude taxonomique d'entérobactéries appartenant ou apparentées à l'espèce Escherichia coli

1981 ◽  
Vol 27 (1) ◽  
pp. 98-106 ◽  
Author(s):  
F. Gavini ◽  
D. Izard ◽  
P. A. Trinel ◽  
B. Lefebvre ◽  
H. Leclerc
Keyword(s):  
Escherichia Coli ◽  
Numerical Analysis ◽  
Dna Hybridization ◽  
Dna Relatedness ◽  
E Coli ◽  
Definition Of

Phenetic (numerical analysis) and genetic (DNA–DNA hybridization) studies were carried out on strains belonging or related to the species Escherichia coli. They have shown the diversity of its phenotypes, by the presence of plasmidic characters (citrate+, urease+, H2S+, tetrathionate reductase+, raffinose+, and saccharose+). New strains related phenetically to E. coli are also individualized. They showed less than 30% DNA relatedness with E. coli. A new definition of E. coli is presented.

The genetic and physical basis of variability in Escherichia coli strains carrying a reference Inc N group plasmid

1981 ◽  
Vol 27 (6) ◽  
pp. 616-626 ◽  
Author(s):  
M. Konarska-Kozlowska ◽  
V. N. Iyer
Keyword(s):  
Escherichia Coli ◽  
Molecular Weight ◽  
Sequence Homology ◽  
Dna Hybridization ◽  
Tetracycline Resistance ◽  
Resistance Marker ◽  
E Coli ◽  
Reference Plasmid ◽  
Dna Fragment ◽  
K 12

The nature and basis of variability in the conjugational behaviour of RM98+ (RM98-carrying) strains of Escherichia coli K-12 that are otherwise similar in phenotype was studied. An explanation for such variability is provided.Some RM98+ strains of E. coli have a plasmid aggregate, which upon conjugation yields two different conjugative plasmids. The first (pCU1) is an N conjugative group plasmid by all available criteria. The second (pCU2) could not be placed in any conjugative group known among the Enterobacteriaceae. Reciprocal DNA hybridization experiments and the gel patterns displayed by the two plasmid DNAs upon digestion with different restriction endonucleases indicate no extensive sequence homology between pCU1 and pCU2. pCU2 DNA is much longer than pCU1 DNA.Despite the absence of extensive homology, the DNA of pCU1 and pCU2 can interact. Derivatives can be selected that have all the antibiotic markers of the aggregate plasmid but that neither contain nor segregate pCU2. It is shown that in such strains a DNA fragment of molecular weight 7.9 × 106 has been added to pCU1 concurrently with a tetracycline resistance marker originally present in pCU2 and absent in pCU1. These observations suggest that tetracycline resistance in pCU2 may be part of a large translocatable element.RM98 has been used to designate a reference Inc N group plasmid. The results presented indicate that this can lead to ambiguity. pCU1 would now be the appropriate reference plasmid.

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