Topic
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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TL;DR: Three types of new variants of the broad-host-range transposon Tn5 are described, which allow the constitutive expression of downstream genes and can be used to generate transcriptional fusions upon insertion, thus facilitating accurate determinations of gene expression.
353 citations
TL;DR: Charge considerations, enzyme degradation studies, and labilities in acid and alkali lead to a structural assignment for MS I of guanosine 5'-diphosphate or 3'- or 2'-dphosphate (ppGpp).
352 citations
TL;DR: The properties of the lambdakan phage suggest that R factors contain systems capable of mediating genetic exchange in the absence of extensive DNA homology, and it is suggested that such systems of exchange may have played important roles in R factor evolution.
Abstract: Transpositions of segments of R factor (antibiotic resistance plasmids) to bacteriophage lambda have been selected and characterized Cells of Escherichia coli harboring R factors that determine kanamycin resistance were infected with phage lambda, and lambdakan transducing lines were obtained Each of the three examined is unusual when compared to lambda transducing phages containing E coli chromosomal genes: the kan insertions (a) occur at several sites, each well removed from the integration region POP', (b) are not associated with deletion of lambda phage DNA, and (c) are separable from the lambda genome during transduction or during lytic growth Two insertions from the same R factor contain 15 kilobase sequences repeated in inverted order The properties of the lambdakan phage suggest that R factors contain systems capable of mediating genetic exchange in the absence of extensive DNA homology It is suggested that such systems of exchange may have played important roles in R factor evolution
352 citations
TL;DR: Bacterial chromosomes and plasmid DNA from topoisomerase I-defective Escherichia coli strains have been characterized with respect to superhelical density and it is shown that topoisomersase I is involved in determining the level of supercoiling in bacteria.
352 citations
TL;DR: The relationship between the structure of lipopolysaccharide and the virulence of bacteria is discussed, and the recent discovery of additional enzymes and gene products that can modify the basic structure in some bacteria, especially pathogens are discussed.
351 citations