Nomenclature & Abbreviations
A listed gene name means that gene carries a loss of function mutation, a Δ preceding a gene name means the gene is deleted. If a gene is not listed, it is not known to be mutated. Prophages present in wt K-12 strains (F, λ, e14, rac) are listed only if absent. E. coli B strains are naturally lon- and dcm-.
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F- = Does not carry the F plasmid
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F+ = Carries the F plasmid. The cell is able to mate with F- through conjugation.
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F'[ ] = Carries an F plasmid that has host chromosomal genes on it from a previous recombination event. This cell can also mate with F- through conjugation. Chromosomal genes carried in the F plasmid are listed in brackets.
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rB/K +/- = The (B/K) defines the strain lineage. The +/- indicates whether the strain has or hasn't got the restriction system.
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mB/K +/- = The (B/K) defines the strain lineage. The +/- indicates whether the strain has or hasn't got the modification (methylation) system.
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hsdS = Both restriction and methylation of certain sequences is deleted from the strain. If you transform DNA from such a strain into a wild type strain, it will be degraded.
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hsdR = For efficient transformation of cloned unmethylated DNA from PCR amplifications
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INV( ) = chromosomal inversion between locations indicated
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ahpC = mutation to alkyl hydroperoxide reductase conferring disulfide reductase activity
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ara-14 = cannot metabolize arabinose
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araD = mutation in L-ribulose-phosphate 4-epimerase blocks arabinose metabolism
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cycA = mutation in alanine transporter; cannot use alanine as a carbon source
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dapD = mutation in succinyl diaminopimelate aminotransferase leads to succinate or (lysine + methionine) requirement
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Δ( ) = chromosomal deletion of genes between the listed genes (may include unlisted genes!)
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dam = adenine methylation at GATC sequences exist; high recombination efficiency; DNA repair turned on
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dcm = cytosine methylation at second C of CCWGG sites exist. dam & dcm are the default properties and always elided, while dam- or dcm- should be declare explicitly
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deoR = regulatory gene that allows constitutive expression of deoxyribose synthesis genes; permits uptake of large plasmids. See Hanahan D, US Patent 4,851,348 . ***This has been called into question, as the DH10B genome sequence revealed that it is deoR+ . See Durfee08, PMID 18245285 .
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dnaJ = one of the chaparonins inactivated; stabilizes some mutant proteins
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dut 1 = dUTPase activity abolished, leading to increased dUTP concentrations, allowing uracil instead of thymine incorporation in DNA. Stable U incorporation requires ung gene mutation as well.
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endA1 = For cleaner preparations of DNA and better results in downstream applications due to the elimination of non-specific digestion by Endonuclease I
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(e14) = excisable prophage like element containing mcrA gene; present in K-12 but missing in many other strains
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galE = mutations are associated with high competence, increased resistance to phage P1 infection, and 2-deoxygalactose resistance. galE mutations block the production of UDP-galactose, resulting in truncation of LPS glycans to the minimal, "inner core". The exceptional competence of DH10B/TOP10 is thought to be a result of a reduced interference from LPS in the binding and/or uptake of transforming DNA. galE15 is a point mutation resulting in a Ser123 -> Phe conversion near the enzyme's active site. See van Die, et al. (责任编辑：大汉昆仑王)
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