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Escherichia coli

About: Escherichia coli is a research topic. Over the lifetime, 59041 publications have been published within this topic receiving 2050337 citations. The topic is also known as: E. coli & E coli jdj.


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Journal ArticleDOI
TL;DR: The requirement for CsdA in derepression of heat-shock protein synthesis is a cold shock-induced function possibly mediated by destabilization of secondary structures previously identified in the rpoH mRNA.
Abstract: A 70-kDa protein was specifically induced in Escherichia coli when the culture temperature was shifted from 37 to 15 degrees C. The protein was identified to be the product of the deaD gene (reassigned csdA) encoding a DEAD-box protein. Furthermore, after the shift from 37 to 15 degrees C, CsdA was exclusively localized in the ribosomal fraction and became a major ribosomal-associated protein in cells grown at 15 degrees C. The csdA deletion significantly impaired cell growth and the synthesis of a number of proteins, specifically the derepression of heat-shock proteins, at low temperature. Purified CsdA was found to unwind double-stranded RNA in the absence of ATP. Therefore, the requirement for CsdA in derepression of heat-shock protein synthesis is a cold shock-induced function possibly mediated by destabilization of secondary structures previously identified in the rpoH mRNA.

332 citations

Journal ArticleDOI
TL;DR: SOS-mediated induction of toxin synthesis appears to be coregulated through induction of the integrated bacteriophage that encodes the toxin gene, and the use of SOS-inducing antibiotics in clinical practice and animal husbandry may account for the recent emergence of STEC disease.
Abstract: Toxin synthesis by Shiga toxin-producing Escherichia coli (STEC) appears to be coregulated through induction of the integrated bacteriophage that encodes the toxin gene. Phage production is linked to induction of the bacterial SOS response, a ubiquitous response to DNA damage. SOS-inducing antimicrobial agents, particularly the quinolones, trimethoprim, and furazolidone, were shown to induce toxin gene expression in studies of their effects on a reporter STEC strain carrying a chromosomebased stx2::lacZ transcriptional fusion. At antimicrobial levels above those required to inhibit bacterial replication, these agents are potent inducers (up to 140-fold) of the transcription of type 2 Shiga toxin genes (stx2); therefore, they should be avoided in treating patients with potential or confirmed STEC infections. Other agents (20 studied) and incubation conditions produced significant but less striking effects on stx2 transcription; positive and negative influences were observed. SOS-mediated induction of toxin synthesis also provides a mechanism that could exacerbate STEC infections and increase dissemination of stx genes. These features and the use of SOS-inducing antibiotics in clinical practice and animal husbandry may account for the recent emergence of STEC disease.

332 citations

Journal ArticleDOI
TL;DR: Inclusion of potassium tellurite in sorbitol-MacConkey agar markedly increased the rate of isolation of VT+ E. coli O157 from cattle rectal swabs and may do so for other types of specimen.
Abstract: Summary Potassium tellurite was assessed for the selection of verocytotoxigenic (VT+) Escherichia coli O157. MICs were higher for VT+ E. coli O157 than for other strains of E. coli and for Aeromonas spp. MacConkey medium containing sorbitol, tellurite and cefixime (TC-SMAC) permitted the growth of VT+ E. coli O157 and Shigella sonnei but partially or completely inhibited the growth of 67% of other strains of E. coli and all or most strains of other sorbitol-non-fermenting species tested. Of 391 rectal swabs from cattle screened on TC-SMAC medium, 26 yielded isolates of VT+ E. coli O157 whereas sorbitol-MacConkey medium with cefixime and rhamnose yielded only nine isolates. Inclusion of potassium tellurite in sorbitol-MacConkey agar markedly increased the rate of isolation of VT+ E. coli O157 from cattle rectal swabs and may do so for other types of specimen.

331 citations

01 Jan 1973
TL;DR: The results provide an explanation on the enzymological level for the utilization of L-threonine by cell suspensions of certain microorganisms for the biosynthesis of the D-1-amino-2-propanol moiety of Vitamin B 12.
Abstract: ~~~~~~~c~t;;m~+C~+ NAY-+ 3 and D-1-amino-2-propanol dehydrogenase F? D 1 amino-2-propanol + NA&. Each enzyme has been obtained in purified form free of the other; the nature of the reaction catalyzed by the latter dehydrogenase alone and in a coupled system with the former enzyme has been studied. The results provide an explanation on the enzymological level for the utilization of L-threonine by cell suspensions of certain microorganisms for the biosynthesis of the D-1-amino-2-propanol moiety of Vitamin B 12'

331 citations

Journal ArticleDOI
TL;DR: Evidence is reviewed suggesting that McrB restriction of mouse-modified DNA does occur in vivo and does in fact interfere with cloning of specific mouse sequences.
Abstract: The McrA and McrB (modified cytosine restriction) systems of E. coli interfere with incoming DNA containing methylcytosine. DNA from many organisms, including all mammalian and plant DNA, is expected to be sensitive, and this could interfere with cloning experiments. The McrA and B phenotypes of a few strains have been reported previously (1-4). The Mcr phenotypes of 94 strains, primarily derived from E. coli K12, are tabulated here. We briefly review some evidence suggesting that McrB restriction of mouse-modified DNA does occur in vivo and does in fact interfere with cloning of specific mouse sequences.

331 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20242
20232,609
20225,796
20211,236
20201,337
20191,412