Cell-targeted phagemid particles preparation using Escherichia coli bearing ligand-pIII encoding helper phage genome

Abstract The rap mutation of Escherichia coli prevents the growth of bacteriophage lambda. We have isolated phage mutants that compensate for the host deficiency. The mutations, named bar, were genetically located to three different loci of the lambda genome: barI in the attP site, barII in the cIII ea10 region, and barIII within or very near the imm434 region. The level of lambda leftward transcription correlates with rap exclusion. Phage lambda mutants partially defective in the pL promoter or in pL-transcript antitermination showed a Bar- phenotype. Conversely, mutants constitutive for transcription from the pI or pL promoters were excluded more stringently by rap bacteria. We conclude that rap exclusion depends on the magnitude of transcription through the wild type bar loci in the phage genome.

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Antibody selection using clonal cocultivation of Escherichia coli and eukaryotic cells in miniecosystems

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1806718115 ◽

2018 ◽

Vol 115 (27) ◽

pp. E6145-E6151 ◽

Cited By ~ 2

Author(s):

Tianqing Zheng ◽

Jia Xie ◽

Zhuo Yang ◽

Pingdong Tao ◽

Bingbing Shi ◽

...

Keyword(s):

Escherichia Coli ◽

Phage Genome ◽

Biological Systems ◽

Gene Sequencing ◽

Eukaryotic Cells ◽

Target Cells ◽

Antibody Repertoire ◽

Functional Antibodies ◽

Selection Of

We describe a method for the rapid selection of functional antibodies. The method depends on the cocultivation of Escherichia coli that produce phage with target eukaryotic cells in very small volumes. The antibodies on phage induce selectable phenotypes in the target cells, and the nature of the antibody is determined by gene sequencing of the phage genome. To select functional antibodies from the diverse antibody repertoire, we devised a selection platform that contains millions of picoliter-sized droplet ecosystems. In each miniecosystem, the bacteria produce phage displaying unique members of the antibody repertoire. These phage interact only with eukaryotic cells in the same miniecosystem, making phage available directly for activity-based antibody selection in biological systems.

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EFFECT OF UV-IRRADIATED HELPER PHAGE ON TRANSFORMATION AND TRANSFECTION OF ESCHERICHIA COLI BY DNA FROM A TRANSDUCING PHAGE

10.21236/ad0813218 ◽

1967 ◽

Author(s):

Lois M. Swaney ◽

Robert A. Altenbern

Keyword(s):

Escherichia Coli ◽

Helper Phage

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Hijacking the Hijackers: Escherichia coli Pathogenicity Islands Redirect Helper Phage Packaging for Their Own Benefit

Molecular Cell ◽

10.1016/j.molcel.2019.06.017 ◽

2019 ◽

Vol 75 (5) ◽

pp. 1020-1030.e4 ◽

Cited By ~ 7

Author(s):

Alfred Fillol-Salom ◽

Julio Bacarizo ◽

Mohammed Alqasmi ◽

J. Rafael Ciges-Tomas ◽

Roser Martínez-Rubio ◽

...

Keyword(s):

Escherichia Coli ◽

Pathogenicity Islands ◽

Helper Phage

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FACTORS AFFECTING PHAGE-RESTRICTING ABILITY IN RHIZOBIUM LEGUMINOSARUM STRAIN L4

Canadian Journal of Microbiology ◽

10.1139/m66-053 ◽

1966 ◽

Vol 12 (2) ◽

pp. 395-407 ◽

Cited By ~ 4

Author(s):

E. A. Schwinghamer

Keyword(s):

Heat Treatment ◽

Mixed Infection ◽

Rhizobium Leguminosarum ◽

Phage Genome ◽

Plating Efficiency ◽

Multiple Infection ◽

Factors Affecting ◽

Helper Phage ◽

Ultraviolet Light Irradiation ◽

Rapid Inactivation

Rhizobiophage [Formula: see text] is modified, by growth in Rhizobium leguminosarum strain L25, to the [Formula: see text] form, which has a low plating efficiency on host strain L4. Alteration of plating efficiency (EOP) was used as a means of studying the nature of phage-restricting ability in L4 cells. Mixed infection involving another phage or the unrestricted form of [Formula: see text] as helper phage increased EOP on L4 up to 200-fold, depending on time and sequence of infection. Multiple (cooperative) infection with [Formula: see text] or sublethal heat treatment of cells increased EOP by about 1000-fold. Growth of cells after they were heated resulted in fairly rapid recovery of restricting ability. Ultraviolet light irradiation of cells induced a lower order of EOP enhancement (7- to 10-fold), and loss and recovery of restricting ability appeared to occur more slowly. Some evidence of an interaction between de-restricting treatments was noted for irradiation and multiple infection. Rapid inactivation of the restricted phage genome after injection was indicated in experiments in which de-restricting treatments were applied belatedly after infection. The results and their implications concerning the nature of restricting ability are compared with those of other phage–host systems.

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Altered Growth and Envelope Properties of Polylysogens Containing Bacteriophage Lambda N−cI− Prophages

International Journal of Molecular Sciences ◽

10.3390/ijms21051667 ◽

2020 ◽

Vol 21 (5) ◽

pp. 1667

Author(s):

Sailen Barik ◽

Nitai C. Mandal

Keyword(s):

Escherichia Coli ◽

Double Mutant ◽

Phage Genome ◽

Biochemical Properties ◽

Direct Result ◽

Large Set ◽

Temperate Bacteriophage ◽

N Protein ◽

E Coli ◽

Multiple Copies

The bacterial virus lambda (λ) is a temperate bacteriophage that can lysogenize host Escherichia coli (E. coli) cells. Lysogeny requires λ repressor, the cI gene product, which shuts off transcription of the phage genome. The λ N protein, in contrast, is a transcriptional antiterminator, required for expression of the terminator-distal genes, and thus, λ N mutants are growth-defective. When E. coli is infected with a λ double mutant that is defective in both N and cI (i.e., λN-cI-), at high multiplicities of 50 or more, it forms polylysogens that contain 20–30 copies of the λN-cI- genome integrated in the E. coli chromosome. Early studies revealed that the polylysogens underwent “conversion” to long filamentous cells that form tiny colonies on agar. Here, we report a large set of altered biochemical properties associated with this conversion, documenting an overall degeneration of the bacterial envelope. These properties reverted back to those of nonlysogenic E. coli as the metastable polylysogen spontaneously lost the λN-cI- genomes, suggesting that conversion is a direct result of the multiple copies of the prophage. Preliminary attempts to identify lambda genes that may be responsible for conversion ruled out several candidates, implicating a potentially novel lambda function that awaits further studies.

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Regulation of the ColV plasmid-determined iron (III)-aerobactin transport system in Escherichia coli

Journal of Bacteriology ◽

10.1128/jb.152.1.223-231.1982 ◽

1982 ◽

Vol 152 (1) ◽

pp. 223-231

Author(s):

V Braun ◽

R Burkhardt

Keyword(s):

Escherichia Coli ◽

Transport System ◽

Phage Genome ◽

Growth Conditions ◽

Receptor Protein ◽

Iron Regulation ◽

Limited Growth ◽

Iron Supply ◽

Supply Systems ◽

Beta Galactosidase

Regulation by iron was studied in Escherichia coli strains whose iron supply was entirely dependent on the iron(III)-aerobactin system determined by the ColV plasmid. By the insertion of phage Mu (Ap lac) into the ColV plasmid, mutants were selected that could no longer grow in iron-limited media. The inserted Mu (Ap lac) strongly reduced the amount of aerobactin and he cloacin receptor protein formed by the cells. Their production was no longer subject to regulation by iron. The Mu (Ap lac) insertion apparently led to a polar effect on the expression of the presumably closely linked genes that control the synthesis of aerobactin and the cloacin receptor protein. The expression of the beta-galactosidase gene on the inserted phage genome came under the control of the iron state of the cells. Under iron-limited growth conditions, the amount of beta-galactosidase synthesized was, depending on the strain studied, 6 to 30 times higher than under iron-sufficient growth conditions. In fur mutants with an impaired iron regulation of ll iron supply systems studied so far, high amounts of beta-galactosidase were synthesized independent of the cells' iron supply. The results demonstrate an iron-controlled promoter on the ColV plasmid which is subject to regulation by the chromosomal fur gene.

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Isolation and Characterization of a ? Transducing Bacteriophage Carrying the cysE Gene of Escherichia Coli K-12

Australian Journal of Biological Sciences ◽

10.1071/bi9800605 ◽

1980 ◽

Vol 33 (5) ◽

pp. 605

Author(s):

CP Ingle ◽

RE Loughlin

Keyword(s):

Escherichia Coli ◽

E Coli ◽

Helper Phage ◽

Isolation And Characterization ◽

K 12

A specialized" transducing phage carrying the cysE and gpsA genes of E. coli K-12 has been isolated. The transducing phage has been separated from the helper phage on equilibrium gradients and has been shown to be defective. Evidence is presented that the phage kil gene is not expressed.

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