Castellani and Chalmers 1919
Bacillus coli communis Escherich 1885
Escherichia coli (; commonly abbreviated E. coli) is a
- 5S rRNA Database Information on nucleotide sequences of 5S rRNAs and their genes
- ACLAME A CLAssification of Mobile genetic Elements
- AlignACE Matrices that search for additional binding sites in the E. coli genomic sequence
- ArrayExpress Database of functional genomics experiments
- ASAP Comprehensive genome information for several enteric bacteria with community annotation
- BioGPS Gene portal hub
- BRENDA Comprehensive Enzyme Information System
- BSGI Bacterial Structural Genomics Initiative
- CATH Protein Structure Classification
- CBS Genome Atlas
- CDD Conserved Domain Database
- CIBEX Center for Information Biology Gene Expression Database
- Bacteriome E. coli interaction database
- coliBASE (subset of the comparative genomics database xBASE)
- EcoSal Continually updated Web resource based on the classic ASM Press publication Escherichia coli and Salmonella: Cellular and Molecular Biology
- ECODAB The structure of the O-antigens that form the basis of the serological classification of E. coli
- Coli Genetic Stock Center Strains and genetic information on E. coli K-12
- EcoCyc – literature-based curation of the entire genome, and of transcriptional regulation, transporters, and metabolic pathways
- PortEco (formerly EcoliHub) – NIH-funded comprehensive data resource for E. coli K-12 and its phage, plasmids, and mobile genetic elements
- EcoliWiki is the community annotation component of PortEco
- RegulonDB RegulonDB is a model of the complex regulation of transcription initiation or regulatory network of the cell E. coli K-12.
- Uropathogenic Escherichia coli (UPEC)
E. coli databases
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- E. coli: Protecting yourself and your family from a sometimes deadly bacterium
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- at the Norwich Research ParkEscherichia coliCurrent research on
- E. coli gas production from glucose video demonstration
- E. coliThe correct way to write
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- Enterohemorrhagic Escherichia Coli (EHEC) outbreak in Germany
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- Bacteriological water analysis
- Coliform bacteria
- Contamination control
- Dam dcm strain
- Fecal coliforms
- International Code of Nomenclature of Bacteria
- List of bacterial genera named after personal names
- List of strains of Escherichia coli
- Mannan Oligosaccharide based nutritional supplements
- T4 rII system
- 2011 E. coli O104:H4 outbreak
In 1885, the German-Austrian pediatrician prokaryotes placed these in a handful of genera based on their shape and motility (at that time Ernst Haeckel's classification of Bacteria in the kingdom Monera was in place.). Bacterium coli was the type species of the now invalid genus Bacterium when it was revealed that the former type species ("Bacterium triloculare") was missing. Following a revision of Bacterium, it was reclassified as Bacillus coli by Migula in 1895 and later reclassified in the newly created genus Escherichia, named after its original discoverer.
Studies are also being performed attempting to program E. coli to solve complicated mathematics problems, such as the Hamiltonian path problem.
By evaluating the possible combination of nanotechnologies with landscape ecology, complex habitat landscapes can be generated with details at the nanoscale. On such synthetic ecosystems, evolutionary experiments with E. coli have been performed to study the spatial biophysics of adaptation in an island biogeography on-chip.
E. coli was one of the first organisms to have its genome sequenced; the complete genome of E. coli K12 was published by Science in 1997.
In 1946, Joshua Lederberg and Edward Tatum first described the phenomenon known as bacterial conjugation using E. coli as a model bacterium, and it remains the primary model to study conjugation. E. coli was an integral part of the first experiments to understand phage genetics, and early researchers, such as Seymour Benzer, used E. coli and phage T4 to understand the topography of gene structure. Prior to Benzer's research, it was not known whether the gene was a linear structure, or if it had a branching pattern.
E. coli is frequently used as a model organism in microbiology studies. Cultivated strains (e.g. E. coli K12) are well-adapted to the laboratory environment, and, unlike wild-type strains, have lost their ability to thrive in the intestine. Many laboratory strains lose their ability to form biofilms. These features protect wild-type strains from antibodies and other chemical attacks, but require a large expenditure of energy and material resources.
Many proteins previously thought difficult or impossible to be expressed in E. coli in folded form have also been successfully expressed in E. coli. For example, proteins with multiple disulphide bonds may be produced in the periplasmic space or in the cytoplasm of mutants rendered sufficiently oxidizing to allow disulphide-bonds to form, while proteins requiring post-translational modification such as glycosylation for stability or function have been expressed using the N-linked glycosylation system of Campylobacter jejuni engineered into E. coli.
E. coli is a very versatile host for the production of heterologous proteins, and various protein expression systems have been developed which allow the production of recombinant proteins in E. coli. Researchers can introduce genes into the microbes using plasmids which permit high level expression of protein, and such protein may be mass-produced in industrial fermentation processes. One of the first useful applications of recombinant DNA technology was the manipulation of E. coli to produce human insulin.
Because of its long history of laboratory culture and ease of manipulation, E. coli also plays an important role in modern biological engineering and industrial microbiology. The work of Stanley Norman Cohen and Herbert Boyer in E. coli, using plasmids and restriction enzymes to create recombinant DNA, became a foundation of biotechnology.
Role in biotechnology
Model organism in life science research
In May 2011, one E. coli strain, O104:H4, has been the subject of a bacterial outbreak that began in Germany. Certain strains of E. coli are a major cause of foodborne illness. The outbreak started when several people in Germany were infected with enterohemorrhagic E. coli (EHEC) bacteria, leading to hemolytic-uremic syndrome (HUS), a medical emergency that requires urgent treatment. The outbreak did not only concern Germany, but also 11 other countries, including regions in North America. On 30 June 2011, the German Bundesinstitut für Risikobewertung (BfR) (Federal Institute for Risk Assessment, a federal institute within the German Federal Ministry of Food, Agriculture and Consumer Protection) announced that seeds of fenugreek from Egypt were likely the cause of the EHEC outbreak.
Uropathogenic E. coli (UPEC) is one of the main causes of urinary tract infections. It is part of the normal flora in the gut and can be introduced in many ways. In particular for females, the direction of wiping after defecation (wiping back to front) can lead to fecal contamination of the urogenital orifices. Anal intercourse can also introduce this bacterium into the male urethra, and in switching from anal to vaginal intercourse, the male can also introduce UPEC to the female urogenital system. For more information, see the databases at the end of the article or UPEC pathogenicity.
Most E. coli strains do not cause disease, but virulent strains can cause gastroenteritis, urinary tract infections, and neonatal meningitis. In rarer cases, virulent strains are also responsible for hemolytic-uremic syndrome, peritonitis, mastitis, septicemia, and Gram-negative pneumonia.
Role in disease
Nonpathogenic E. coli strain Nissle 1917, also known as Mutaflor, and E. coli O83:K24:H31 (known as Colinfant) are used as a probiotic agents in medicine, mainly for the treatment of various gastroenterological diseases, including inflammatory bowel disease.
Binary interactions. Rajagopala et al. (2014) have carried out systematic yeast two-hybrid screens with most E. coli proteins, and found a total of 2,234 protein-protein interactions. This study also integrated genetic interactions and protein structures and mapped 458 interactions within 227 protein complexes.
Protein complexes. A 2006 study purified 4,339 proteins from cultures of strain K-12 and found interacting partners for 2,667 proteins, many of which had unknown functions at the time. A 2009 study found 5,993 interactions between proteins of the same E. coli strain, though these data showed little overlap with those of the 2006 publication.
Today, over 60 complete genomic sequences of Escherichia and Shigella species are available. Comparison of these sequences shows a remarkable amount of diversity; only about 20% of each genome represents sequences present in every one of the isolates, while around 80% of each genome can vary among isolates. Each individual genome contains between 4,000 and 5,500 genes, but the total number of different genes among all of the sequenced E. coli strains (the pangenome) exceeds 16,000. This very large variety of component genes has been interpreted to mean that two-thirds of the E. coli pangenome originated in other species and arrived through the process of horizontal gene transfer.
The first complete operons), seven ribosomal RNA (rRNA) operons, and 86 transfer RNA (tRNA) genes. Despite having been the subject of intensive genetic analysis for about 40 years, a large number of these genes were previously unknown. The coding density was found to be very high, with a mean distance between genes of only 118 base pairs. The genome was observed to contain a significant number of transposable genetic elements, repeat elements, cryptic prophages, and bacteriophage remnants.
The link between phylogenetic distance ("relatedness") and pathology is small, e.g. the O157:H7 serotype strains, which form a clade ("an exclusive group")—group E below—are all enterohaemorragic strains (EHEC), but not all EHEC strains are closely related. In fact, four different species of Shigella are nested among E. coli strains (vide supra), while E. albertii and E. fergusonii are outside of this group. All commonly used research strains of E. coli belong to group A and are derived mainly from Clifton's K-12 strain (λ⁺ F⁺; O16) and to a lesser degree from d'Herelle's Bacillus coli strain (B strain)(O7).
A large number of strains belonging to this species have been isolated and characterised. In addition to serotype (vide supra), they can be classified according to their phylogeny, i.e. the inferred evolutionary history, as shown below where the species is divided into six groups.
Phylogeny of E. coli strains
The original strain described by Escherich is believed to be lost, consequently a new type strain (neotype) was chosen as a representative: the neotype strain is ATCC 11775, also known as NCTC 9001, which is pathogenic to chickens and has an O1:K1:H7 serotype. However, in most studies, either O157:H7, K-12 MG1655, or K-12 W3110 are used as a representative E.coli.
E. coli is the type species of the genus (Escherichia) and in turn Escherichia is the type genus of the family Enterobacteriaceae, where the family name does not stem from the genus Enterobacter + "i" (sic.) + "aceae", but from "enterobacterium" + "aceae" (enterobacterium being not a genus, but an alternative trivial name to enteric bacterium).
The long-term evolution experiments using E. coli, begun by Richard Lenski in 1988, have allowed direct observation of major evolutionary shifts in the laboratory. In this experiment, one population of E. coli unexpectedly evolved the ability to aerobically metabolize citrate, which is extremely rare in E. coli. As the inability to grow aerobically is normally used as a diagnostic criterion with which to differentiate E. coli from other, closely related bacteria, such as Salmonella, this innovation may mark a speciation event observed in the laboratory.
The genera Escherichia and Salmonella diverged around 102 million years ago (credibility interval: 57–176 mya), which coincides with the divergence of their hosts: the former being found in mammals and the latter in birds and reptiles. This was followed by a split of the escherichian ancestor into five species (E. albertii, E. coli, E. fergusonii, E. hermannii, and E. vulneris.) The last E. coli ancestor split between 20 and 30 million years ago.
Like all lifeforms, new strains of E. coli evolve through the natural biological processes of mutation, gene duplication, and horizontal gene transfer, in particular 18% of the genome of the laboratory strain MG1655 was horizontally acquired since the divergence from Salmonella. E. coli K-12 and E. coli B strains are the most frequently used varieties for laboratory purposes. Some strains develop traits that can be harmful to a host animal. These virulent strains typically cause a bout of diarrhea that is unpleasant in healthy adults and is often lethal to children in the developing world. More virulent strains, such as O157:H7, cause serious illness or death in the elderly, the very young, or the immunocompromised.
Genome plasticity and evolution
A common subdivision system of E. coli, but not based on evolutionary relatedness, is by serotype, which is based on major surface antigens (O antigen: part of lipopolysaccharide layer; H: flagellin; K antigen: capsule), e.g. O157:H7). It is, however, common to cite only the serogroup, i.e. the O-antigen. At present, about 190 serogroups are known. The common laboratory strain has a mutation that prevents the formation of an O-antigen and is thus not typeable.
A strain is a subgroup within the species that has unique characteristics that distinguish it from other strains. These differences are often detectable only at the molecular level; however, they may result in changes to the physiology or lifecycle of the bacterium. For example, a strain may gain pathogenic capacity, the ability to use a unique carbon source, the ability to take upon a particular ecological niche, or the ability to resist antimicrobial agents. Different strains of E. coli are often host-specific, making it possible to determine the source of fecal contamination in environmental samples. For example, knowing which E. coli strains are present in a water sample allows researchers to make assumptions about whether the contamination originated from a human, another mammal, or a bird.
In fact, from the evolutionary point of view, the members of genus Shigella (S. dysenteriae, S. flexneri, S. boydii, and S. sonnei) should be classified as E. coli strains, a phenomenon termed taxa in disguise. Similarly, other strains of E. coli (e.g. the K-12 strain commonly used in recombinant DNA work) are sufficiently different that they would merit reclassification.
Escherichia coli encompasses an enormous population of bacteria that exhibit a very high degree of both genetic and phenotypic diversity. Genome sequencing of a large number of isolates of E. coli and related bacteria shows that a taxonomic reclassification would be desirable. However, this has not been done, largely due to its medical importance and E. coli remains one of the most diverse bacterial species: only 20% of the genome is common to all strains.
E. coli and related bacteria possess the ability to transfer DNA via bacterial conjugation, transduction or transformation, which allows genetic material to spread horizontally through an existing population. This process led to the spread of the gene encoding shiga toxin from Shigella to E. coli O157:H7, carried by a bacteriophage.
Optimal growth of E. coli occurs at 37 °C (98.6 °F), but some laboratory strains can multiply at temperatures of up to 49 °C. Growth can be driven by aerobic or anaerobic respiration, using a large variety of redox pairs, including the oxidation of pyruvic acid, formic acid, hydrogen, and amino acids, and the reduction of substrates such as oxygen, nitrate, fumarate, dimethyl sulfoxide, and trimethylamine N-oxide.
E. coli is methanogens or sulphate-reducing bacteria.
Biology and biochemistry
- Biology and biochemistry 1
- Serotypes 2.1
- Genome plasticity and evolution 2.2
- Neotype strain 2.3
- Phylogeny of E. coli strains 2.4
- Genomics 3
- Proteome 4.1
- Interactome 4.2
Normal microbiota 5
- Therapeutic use 5.1
- Role in disease 6
Model organism in life science research 7
- Role in biotechnology 7.1
- Model organism 7.2
- History 8
- See also 9
- References 10
- Further reading 11
External links 12
- E. coli databases 12.1
- General databases with E. coli-related information 12.2
The bacterium can be grown easily and inexpensively in a laboratory setting, and has been intensively investigated for over 60 years. E. coli is the most widely studied recombinant DNA. Under favourable conditions, it takes only 20 minutes to reproduce.
E. coli and other facultative anaerobes constitute about 0.1% of fecal contamination. A growing body of research, though, has examined environmentally persistent E. coli which can survive for extended periods outside of a host.
 bacteria.pathogenic and preventing colonization of the intestine with ,vitamin K2, and can benefit their hosts by producing gut of the normal flora The harmless strains are part of the .food contamination due to product recalls in their hosts, and are occasionally responsible for food poisoning can cause serious serotypes are harmless, but some strains E. coli Most