e coli competent cells  (Millipore)


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    Name:
    e coli protein expression
    Description:
    BL21 DE3 T1R are competent E coli that are suitable for high level induction and expression genes regulated by expression vectors with T7 promoter The cells have transformation efficiency of 1x107 cfu mug when transformed with non saturating amounts of pUC19 plasmid DNA
    Catalog Number:
    b2935
    Price:
    None
    Applications:
    Suitable for induction and expression of genes directed by the expression systems with T7 promoter
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    Structured Review

    Millipore e coli competent cells
    BL21 DE3 T1R are competent E coli that are suitable for high level induction and expression genes regulated by expression vectors with T7 promoter The cells have transformation efficiency of 1x107 cfu mug when transformed with non saturating amounts of pUC19 plasmid DNA
    https://www.bioz.com/result/e coli competent cells/product/Millipore
    Average 99 stars, based on 15 article reviews
    Price from $9.99 to $1999.99
    e coli competent cells - by Bioz Stars, 2020-08
    99/100 stars

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    Related Articles

    Clone Assay:

    Article Title: The RuvA Homologues from Mycoplasma genitalium and Mycoplasma pneumoniae Exhibit Unique Functional Characteristics
    Article Snippet: .. The resulting 0.6-kilobase pairs (kb) PCR fragment was digested with Nde I and Bam HI (the recognition sites for these enzymes are indicated in italics in the sequences of primers RuvAmpn_fw and RuvAmpn_rev, respectively), and cloned into Nde I- and Bam HI-digested E. coli protein expression vectors, i.e. pET-11c and pET-16b (Novagen), generating plasmids pET-11c-RuvAMpn and pET-16b-RuvAMpn , respectively. .. Plasmid pET-11c-RuvAMpn was used for expression of native RuvAMpn , while plasmid pET-16b-RuvAMpn was employed for expression of RuvAMpn as an N-terminally poly histidine (H10 )-tagged protein in E. coli .

    Positron Emission Tomography:

    Article Title: Yeast-based assays for the high-throughput screening of inhibitors of coronavirus RNA cap guanine-N7-methyltransferase
    Article Snippet: .. 2.2 Protein expression and purification E. coli BL21 (DE3) cells (Novagen) were separately transformed with the pET30a-SARS-nsp14, pET30a-MHV-nsp14, pET-duet1-TGEV-nsp14, and pDest14-IBV-nsp14 plasmids. .. The cells were cultured at 37 °C in 1 L of LB medium supplemented with kanamycin (50 μg/ml) or ampicillin (100 μg/ml) until the culture density (A600 ) reached 0.6–0.8 and then induced with 0.5 mM isopropyl-β-d -1-thiogalactopyranoside (IPTG) for 20 h at 16 °C.

    Article Title: The RuvA Homologues from Mycoplasma genitalium and Mycoplasma pneumoniae Exhibit Unique Functional Characteristics
    Article Snippet: .. The resulting 0.6-kilobase pairs (kb) PCR fragment was digested with Nde I and Bam HI (the recognition sites for these enzymes are indicated in italics in the sequences of primers RuvAmpn_fw and RuvAmpn_rev, respectively), and cloned into Nde I- and Bam HI-digested E. coli protein expression vectors, i.e. pET-11c and pET-16b (Novagen), generating plasmids pET-11c-RuvAMpn and pET-16b-RuvAMpn , respectively. .. Plasmid pET-11c-RuvAMpn was used for expression of native RuvAMpn , while plasmid pET-16b-RuvAMpn was employed for expression of RuvAMpn as an N-terminally poly histidine (H10 )-tagged protein in E. coli .

    Construct:

    Article Title: The Central Stalk Determines the Motility of Mitotic Kinesin-14 Homodimers.
    Article Snippet: .. Protein expression in E.coli All protein constructs were expressed in BL21(DE3) Rosetta cells (Novagen). ..

    Purification:

    Article Title: A splice site-sensing conformational switch in U2AF2 is modulated by U2AF1 and its recurrent myelodysplasia-associated mutation
    Article Snippet: .. Protein expression and purification All proteins were expressed in BL21(DE3) (for expression or co-expression of pCDF-1b vectors) or BL21 (for pGEX-6p vectors) by overnight induction with 0.2 mM isopropyl β-d -1-thiogalactopyranoside at 18°C. .. In general, affinity purifications followed the HiTrap manufacturer's protocols and included cOmplete™ EDTA-free protease inhibitors (Millipore-Sigma), 6 mM β-mercapto-ethanol, and 0.2 tris(2-carboxyethyl) phosphine (TCEP) reducing agents in the buffers.

    Article Title: Yeast-based assays for the high-throughput screening of inhibitors of coronavirus RNA cap guanine-N7-methyltransferase
    Article Snippet: .. 2.2 Protein expression and purification E. coli BL21 (DE3) cells (Novagen) were separately transformed with the pET30a-SARS-nsp14, pET30a-MHV-nsp14, pET-duet1-TGEV-nsp14, and pDest14-IBV-nsp14 plasmids. .. The cells were cultured at 37 °C in 1 L of LB medium supplemented with kanamycin (50 μg/ml) or ampicillin (100 μg/ml) until the culture density (A600 ) reached 0.6–0.8 and then induced with 0.5 mM isopropyl-β-d -1-thiogalactopyranoside (IPTG) for 20 h at 16 °C.

    Article Title: Coronavirus nucleocapsid protein is an RNA chaperone
    Article Snippet: .. Protein expression and purification E. coli cells of the strain BL21(DE3)pLys (Novagen) were transformed with plasmids pGEX-4T-2, pGEX4T2-N, pGEX4T2-hnRNPA1, or pET28a-PTB. .. For GST, GST-N and GST-hnRNPA1 expression and purification, a 250 ml culture was grown at 37°C to approximately 0.5 OD600 .

    Expressing:

    Article Title: Efficacy of recombinant measles virus expressing highly pathogenic avian influenza virus (HPAIV) antigen against HPAIV infection in monkeys
    Article Snippet: .. The H5 HA gene was ligated to the E. coli protein expression vector pET21b (Novagen), from which the recombinant protein was expressed as a fusion protein with a histidine tag. .. Competent BL21 cells were transformed with the plasmid to express the protein at high levels.

    Article Title: A splice site-sensing conformational switch in U2AF2 is modulated by U2AF1 and its recurrent myelodysplasia-associated mutation
    Article Snippet: .. Protein expression and purification All proteins were expressed in BL21(DE3) (for expression or co-expression of pCDF-1b vectors) or BL21 (for pGEX-6p vectors) by overnight induction with 0.2 mM isopropyl β-d -1-thiogalactopyranoside at 18°C. .. In general, affinity purifications followed the HiTrap manufacturer's protocols and included cOmplete™ EDTA-free protease inhibitors (Millipore-Sigma), 6 mM β-mercapto-ethanol, and 0.2 tris(2-carboxyethyl) phosphine (TCEP) reducing agents in the buffers.

    Article Title: Yeast-based assays for the high-throughput screening of inhibitors of coronavirus RNA cap guanine-N7-methyltransferase
    Article Snippet: .. 2.2 Protein expression and purification E. coli BL21 (DE3) cells (Novagen) were separately transformed with the pET30a-SARS-nsp14, pET30a-MHV-nsp14, pET-duet1-TGEV-nsp14, and pDest14-IBV-nsp14 plasmids. .. The cells were cultured at 37 °C in 1 L of LB medium supplemented with kanamycin (50 μg/ml) or ampicillin (100 μg/ml) until the culture density (A600 ) reached 0.6–0.8 and then induced with 0.5 mM isopropyl-β-d -1-thiogalactopyranoside (IPTG) for 20 h at 16 °C.

    Article Title: Coronavirus nucleocapsid protein is an RNA chaperone
    Article Snippet: .. Protein expression and purification E. coli cells of the strain BL21(DE3)pLys (Novagen) were transformed with plasmids pGEX-4T-2, pGEX4T2-N, pGEX4T2-hnRNPA1, or pET28a-PTB. .. For GST, GST-N and GST-hnRNPA1 expression and purification, a 250 ml culture was grown at 37°C to approximately 0.5 OD600 .

    Article Title: The Central Stalk Determines the Motility of Mitotic Kinesin-14 Homodimers.
    Article Snippet: .. Protein expression in E.coli All protein constructs were expressed in BL21(DE3) Rosetta cells (Novagen). ..

    Article Title: The RuvA Homologues from Mycoplasma genitalium and Mycoplasma pneumoniae Exhibit Unique Functional Characteristics
    Article Snippet: .. The resulting 0.6-kilobase pairs (kb) PCR fragment was digested with Nde I and Bam HI (the recognition sites for these enzymes are indicated in italics in the sequences of primers RuvAmpn_fw and RuvAmpn_rev, respectively), and cloned into Nde I- and Bam HI-digested E. coli protein expression vectors, i.e. pET-11c and pET-16b (Novagen), generating plasmids pET-11c-RuvAMpn and pET-16b-RuvAMpn , respectively. .. Plasmid pET-11c-RuvAMpn was used for expression of native RuvAMpn , while plasmid pET-16b-RuvAMpn was employed for expression of RuvAMpn as an N-terminally poly histidine (H10 )-tagged protein in E. coli .

    Polymerase Chain Reaction:

    Article Title: The RuvA Homologues from Mycoplasma genitalium and Mycoplasma pneumoniae Exhibit Unique Functional Characteristics
    Article Snippet: .. The resulting 0.6-kilobase pairs (kb) PCR fragment was digested with Nde I and Bam HI (the recognition sites for these enzymes are indicated in italics in the sequences of primers RuvAmpn_fw and RuvAmpn_rev, respectively), and cloned into Nde I- and Bam HI-digested E. coli protein expression vectors, i.e. pET-11c and pET-16b (Novagen), generating plasmids pET-11c-RuvAMpn and pET-16b-RuvAMpn , respectively. .. Plasmid pET-11c-RuvAMpn was used for expression of native RuvAMpn , while plasmid pET-16b-RuvAMpn was employed for expression of RuvAMpn as an N-terminally poly histidine (H10 )-tagged protein in E. coli .

    Transformation Assay:

    Article Title: Development and Characterization of a Camelid Single Domain Antibody–Urease Conjugate That Targets Vascular Endothelial Growth Factor Receptor 2
    Article Snippet: .. Transformation of BL21 (DE3) competent E. coli cells (Sigma, B2935-10 × 50 µL) was according to the manufacturer’s instructions. .. One colony from a transformation plate was aseptically inoculated to 200 mL of LB broth (LB media EZ mix, Sigma cat #L76581, 20 g/L) supplemented with 50 mg/L kanamycin.

    Article Title: Yeast-based assays for the high-throughput screening of inhibitors of coronavirus RNA cap guanine-N7-methyltransferase
    Article Snippet: .. 2.2 Protein expression and purification E. coli BL21 (DE3) cells (Novagen) were separately transformed with the pET30a-SARS-nsp14, pET30a-MHV-nsp14, pET-duet1-TGEV-nsp14, and pDest14-IBV-nsp14 plasmids. .. The cells were cultured at 37 °C in 1 L of LB medium supplemented with kanamycin (50 μg/ml) or ampicillin (100 μg/ml) until the culture density (A600 ) reached 0.6–0.8 and then induced with 0.5 mM isopropyl-β-d -1-thiogalactopyranoside (IPTG) for 20 h at 16 °C.

    Article Title: Coronavirus nucleocapsid protein is an RNA chaperone
    Article Snippet: .. Protein expression and purification E. coli cells of the strain BL21(DE3)pLys (Novagen) were transformed with plasmids pGEX-4T-2, pGEX4T2-N, pGEX4T2-hnRNPA1, or pET28a-PTB. .. For GST, GST-N and GST-hnRNPA1 expression and purification, a 250 ml culture was grown at 37°C to approximately 0.5 OD600 .

    Article Title: A Non-Motor Microtubule Binding Site Is Essential for the High Processivity and Mitotic Function of Kinesin-8 Kif18A
    Article Snippet: .. Kif18A776-898 –GFP and Kif18A898 –GFP were expressed in BL21(DE3)-T1R competent Escherichia coli (Sigma B2935) transformed with pRARE (Novagen, # 70954). .. Expression was induced at OD 0.6 with 0.5 mM IPTG over night at 18°C.

    Recombinant:

    Article Title: Efficacy of recombinant measles virus expressing highly pathogenic avian influenza virus (HPAIV) antigen against HPAIV infection in monkeys
    Article Snippet: .. The H5 HA gene was ligated to the E. coli protein expression vector pET21b (Novagen), from which the recombinant protein was expressed as a fusion protein with a histidine tag. .. Competent BL21 cells were transformed with the plasmid to express the protein at high levels.

    Plasmid Preparation:

    Article Title: Efficacy of recombinant measles virus expressing highly pathogenic avian influenza virus (HPAIV) antigen against HPAIV infection in monkeys
    Article Snippet: .. The H5 HA gene was ligated to the E. coli protein expression vector pET21b (Novagen), from which the recombinant protein was expressed as a fusion protein with a histidine tag. .. Competent BL21 cells were transformed with the plasmid to express the protein at high levels.

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    Millipore hygromycin b
    Hygromycin B, supplied by Millipore, used in various techniques. Bioz Stars score: 99/100, based on 574 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
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    Millipore escherichia coli cells
    Overmethylation alleviates the highly restrictive phenotype and suppresses the autorestriction defects. <t>Escherichia</t> coli ER1992 (A) or MP060 cells (B, C) carrying pACYCeco or pIM-RM plasmids were co-transformed with pBADecoM carrying the arabinose inducible ecoRIM gene. MTase expression was induced with 0.04% for 1 h at 37 °C (A) or overnight (B, C). Then, a quantitative assay for restriction λ vir phage DNA was performed (A), and SOS-inducing YFP fluorescence was measured (B) or microscopy of cells was conducted (C).
    Escherichia Coli Cells, supplied by Millipore, used in various techniques. Bioz Stars score: 92/100, based on 30 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
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    Millipore rosetta de3 competitive cells
    Overmethylation alleviates the highly restrictive phenotype and suppresses the autorestriction defects. <t>Escherichia</t> coli ER1992 (A) or MP060 cells (B, C) carrying pACYCeco or pIM-RM plasmids were co-transformed with pBADecoM carrying the arabinose inducible ecoRIM gene. MTase expression was induced with 0.04% for 1 h at 37 °C (A) or overnight (B, C). Then, a quantitative assay for restriction λ vir phage DNA was performed (A), and SOS-inducing YFP fluorescence was measured (B) or microscopy of cells was conducted (C).
    Rosetta De3 Competitive Cells, supplied by Millipore, used in various techniques. Bioz Stars score: 92/100, based on 1 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
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    Average 92 stars, based on 1 article reviews
    Price from $9.99 to $1999.99
    rosetta de3 competitive cells - by Bioz Stars, 2020-08
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    Overmethylation alleviates the highly restrictive phenotype and suppresses the autorestriction defects. Escherichia coli ER1992 (A) or MP060 cells (B, C) carrying pACYCeco or pIM-RM plasmids were co-transformed with pBADecoM carrying the arabinose inducible ecoRIM gene. MTase expression was induced with 0.04% for 1 h at 37 °C (A) or overnight (B, C). Then, a quantitative assay for restriction λ vir phage DNA was performed (A), and SOS-inducing YFP fluorescence was measured (B) or microscopy of cells was conducted (C).

    Journal: DNA Research: An International Journal for Rapid Publication of Reports on Genes and Genomes

    Article Title: Low-level expression of the Type II restriction–modification system confers potent bacteriophage resistance in Escherichia coli

    doi: 10.1093/dnares/dsaa003

    Figure Lengend Snippet: Overmethylation alleviates the highly restrictive phenotype and suppresses the autorestriction defects. Escherichia coli ER1992 (A) or MP060 cells (B, C) carrying pACYCeco or pIM-RM plasmids were co-transformed with pBADecoM carrying the arabinose inducible ecoRIM gene. MTase expression was induced with 0.04% for 1 h at 37 °C (A) or overnight (B, C). Then, a quantitative assay for restriction λ vir phage DNA was performed (A), and SOS-inducing YFP fluorescence was measured (B) or microscopy of cells was conducted (C).

    Article Snippet: Escherichia coli cells were grown in LB medium with antibiotics at the following concentrations when necessary: ampicillin (Ap) at 100 μg/ml, chloramphenicol (Cm) at 30 μg/ml, and tetracycline (Tc) 15 μg/ml.

    Techniques: Transformation Assay, Expressing, Fluorescence, Microscopy

    Phage restriction variation in Escherichia coli cells carrying the EcoRI R–M system measured as phage λ vir infection efficiency. (A) The qualitative assay involved 5 μl of serial dilutions of λb2 vir phage, which were spotted onto LB agar plates with an E. coli ER1992 lawn carrying the indicated plasmids or no plasmids [ER1992E (EcoRI R–M) + strain] and incubated overnight at 37 °C. Quantitative results of the restriction activity of E. coli ER1992 strains. EOP, efficiency of plaques, PFUs tested on plasmid/strains divided by PFUs on pACYC184; and RR, restriction relative to the pIM-RM bearing strain. The standard deviation from at least three measurements is indicated. (B) Western blots of the lysates of the late exponential phase harvested MG1655 bacteria carrying: pACYCeco, pIM-RM, pBAD-RM, and pACYCΔnutL. Lanes R contain a purified R.EcoRI preparation. Lane ‘sm’ contains molecular size markers. The levels of R.EcoRI and M.EcoRI proteins in bacterial crude extracts were tested by western blotting using rabbit anti-M.EcoRI and anti-R.EcoRI polyclonal antibodies and visualized by BCIP/NBT (nitroblue tetrazolium) as the color development reagent. The star and white circles indicate the location of unknown antigen proteins. Note that expression of the EcoRI R–M system on pBAD-RM was induced using 0.04% l -arabinose for 2 h. (C) Relative strength of the P L1 promoter and nutL /N anti-termination in pACYCeco expressed as reporter LacZ activity. Error bars represent standard deviations from at least three independent experiments. (D) The anti-termination-mediated increase of ecoRIR expression from pACYCeco plasmid, by λ-N protein, 10, 20, 30, 40, and 60 min after infection. Note that the cell lysis was observed after 60 min of post-infection time (Line 8), thus the bacterial lysate might be non-representative. Also shown is the comparison of the expression levels of the ecoRIRM from pIM-RM after 30 min of λ vir phage infection. The star indicates the location of the unknown antigen protein, and the arrow indicates the position of the R.EcoRI enzyme.

    Journal: DNA Research: An International Journal for Rapid Publication of Reports on Genes and Genomes

    Article Title: Low-level expression of the Type II restriction–modification system confers potent bacteriophage resistance in Escherichia coli

    doi: 10.1093/dnares/dsaa003

    Figure Lengend Snippet: Phage restriction variation in Escherichia coli cells carrying the EcoRI R–M system measured as phage λ vir infection efficiency. (A) The qualitative assay involved 5 μl of serial dilutions of λb2 vir phage, which were spotted onto LB agar plates with an E. coli ER1992 lawn carrying the indicated plasmids or no plasmids [ER1992E (EcoRI R–M) + strain] and incubated overnight at 37 °C. Quantitative results of the restriction activity of E. coli ER1992 strains. EOP, efficiency of plaques, PFUs tested on plasmid/strains divided by PFUs on pACYC184; and RR, restriction relative to the pIM-RM bearing strain. The standard deviation from at least three measurements is indicated. (B) Western blots of the lysates of the late exponential phase harvested MG1655 bacteria carrying: pACYCeco, pIM-RM, pBAD-RM, and pACYCΔnutL. Lanes R contain a purified R.EcoRI preparation. Lane ‘sm’ contains molecular size markers. The levels of R.EcoRI and M.EcoRI proteins in bacterial crude extracts were tested by western blotting using rabbit anti-M.EcoRI and anti-R.EcoRI polyclonal antibodies and visualized by BCIP/NBT (nitroblue tetrazolium) as the color development reagent. The star and white circles indicate the location of unknown antigen proteins. Note that expression of the EcoRI R–M system on pBAD-RM was induced using 0.04% l -arabinose for 2 h. (C) Relative strength of the P L1 promoter and nutL /N anti-termination in pACYCeco expressed as reporter LacZ activity. Error bars represent standard deviations from at least three independent experiments. (D) The anti-termination-mediated increase of ecoRIR expression from pACYCeco plasmid, by λ-N protein, 10, 20, 30, 40, and 60 min after infection. Note that the cell lysis was observed after 60 min of post-infection time (Line 8), thus the bacterial lysate might be non-representative. Also shown is the comparison of the expression levels of the ecoRIRM from pIM-RM after 30 min of λ vir phage infection. The star indicates the location of the unknown antigen protein, and the arrow indicates the position of the R.EcoRI enzyme.

    Article Snippet: Escherichia coli cells were grown in LB medium with antibiotics at the following concentrations when necessary: ampicillin (Ap) at 100 μg/ml, chloramphenicol (Cm) at 30 μg/ml, and tetracycline (Tc) 15 μg/ml.

    Techniques: Infection, Incubation, Activity Assay, Plasmid Preparation, Standard Deviation, Western Blot, Purification, Expressing, Lysis

    The SOS response induction and R–M system instability in cells carrying the plasmid with the high R–M genes expression. (A) Escherichia coli strain SS996, where the gfp gene is under the control of the P sulA promoter, was transformed with the following plasmids: pIM-RM (high R–M genes expression), pACYCeco (low R–M genes expression) and pBAD-RM, where REase expression was induced by 0.04% of l -arabinose for 2 h. Light and fluorescence microscopy images were captured. (B) The SOS response was also measured quantitatively for the same plasmids in E. coli strains with the YFP reporter gene under the control of the P sulA promoter in the background of recA + (MP060) and recA − (MP064). As a control, the plasmid, pIM-RM, with a kanamycin resistance cassette inserted in cat gene upstream of the P R promoter for REase gene (pIM-RMkan) was used, as well as strains without plasmids. (C) Plasmids pIM-RM and pACYCeco (both restriction proficient R + M + ; high and low REase producers) were challenged using a 3-day growth competition assay to generate the co-cultures with the MG1655 strain without a plasmid (no RM system). As a control, plasmid with a restriction-negative variant was also used (pIM27: R − M + ). Briefly, strains without plasmid were mixed 1:1 with cells carrying plasmid with the R–M system variant and allowed to grow in the co-cultures for 60 generations. Chloramphenicol resistance was used as a selection marker for CFUs of cells carrying the R–M system variants. The cell viability was measured at Generations 1 and 60, and calculated as the ratio of the CFUs on LB agar supplemented with chloramphenicol to the CFUs obtained on LB agar.

    Journal: DNA Research: An International Journal for Rapid Publication of Reports on Genes and Genomes

    Article Title: Low-level expression of the Type II restriction–modification system confers potent bacteriophage resistance in Escherichia coli

    doi: 10.1093/dnares/dsaa003

    Figure Lengend Snippet: The SOS response induction and R–M system instability in cells carrying the plasmid with the high R–M genes expression. (A) Escherichia coli strain SS996, where the gfp gene is under the control of the P sulA promoter, was transformed with the following plasmids: pIM-RM (high R–M genes expression), pACYCeco (low R–M genes expression) and pBAD-RM, where REase expression was induced by 0.04% of l -arabinose for 2 h. Light and fluorescence microscopy images were captured. (B) The SOS response was also measured quantitatively for the same plasmids in E. coli strains with the YFP reporter gene under the control of the P sulA promoter in the background of recA + (MP060) and recA − (MP064). As a control, the plasmid, pIM-RM, with a kanamycin resistance cassette inserted in cat gene upstream of the P R promoter for REase gene (pIM-RMkan) was used, as well as strains without plasmids. (C) Plasmids pIM-RM and pACYCeco (both restriction proficient R + M + ; high and low REase producers) were challenged using a 3-day growth competition assay to generate the co-cultures with the MG1655 strain without a plasmid (no RM system). As a control, plasmid with a restriction-negative variant was also used (pIM27: R − M + ). Briefly, strains without plasmid were mixed 1:1 with cells carrying plasmid with the R–M system variant and allowed to grow in the co-cultures for 60 generations. Chloramphenicol resistance was used as a selection marker for CFUs of cells carrying the R–M system variants. The cell viability was measured at Generations 1 and 60, and calculated as the ratio of the CFUs on LB agar supplemented with chloramphenicol to the CFUs obtained on LB agar.

    Article Snippet: Escherichia coli cells were grown in LB medium with antibiotics at the following concentrations when necessary: ampicillin (Ap) at 100 μg/ml, chloramphenicol (Cm) at 30 μg/ml, and tetracycline (Tc) 15 μg/ml.

    Techniques: Plasmid Preparation, Expressing, Transformation Assay, Fluorescence, Microscopy, Competitive Binding Assay, Variant Assay, Selection, Marker