Bacteriophage Lambda: a Paradigm Revisited

Fogg, Paul C. M.; Allison, Heather E.; Saunders, J. R.; McCarthy, Alan J.

doi:10.1128/jvi.02177-09

Cited by 39 publications

(36 citation statements)

References 24 publications

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“…This essential adsorption target, the fact that many outbreak strains carry more than one Stx phage [46,47], and the capacity of at least some Stx phages to multiply infect a single host cell [15-17,22,48] is likely to foster many opportunities to drive phage evolution through in situ recombination events. Thus the similarities in genome content across the short-tailed phages depicted in Figure 3, excluding lambda and Phi 27 that lie outside this group, may be a consequence of such recombination [49].…”

Section: Resultsmentioning

confidence: 99%

Comparative genomics of Shiga toxin encoding bacteriophages

et al. 2012

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BackgroundStx bacteriophages are responsible for driving the dissemination of Stx toxin genes (stx) across their bacterial host range. Lysogens carrying Stx phages can cause severe, life-threatening disease and Stx toxin is an integral virulence factor. The Stx-bacteriophage vB_EcoP-24B, commonly referred to as Ф24B, is capable of multiply infecting a single bacterial host cell at a high frequency, with secondary infection increasing the rate at which subsequent bacteriophage infections can occur. This is biologically unusual, therefore determining the genomic content and context of Ф24B compared to other lambdoid Stx phages is important to understanding the factors controlling this phenomenon and determining whether they occur in other Stx phages.ResultsThe genome of the Stx2 encoding phage, Ф24B was sequenced and annotated. The genomic organisation and general features are similar to other sequenced Stx bacteriophages induced from Enterohaemorrhagic Escherichia coli (EHEC), however Ф24B possesses significant regions of heterogeneity, with implications for phage biology and behaviour. The Ф24B genome was compared to other sequenced Stx phages and the archetypal lambdoid phage, lambda, using the Circos genome comparison tool and a PCR-based multi-loci comparison system.ConclusionsThe data support the hypothesis that Stx phages are mosaic, and recombination events between the host, phages and their remnants within the same infected bacterial cell will continue to drive the evolution of Stx phage variants and the subsequent dissemination of shigatoxigenic potential.

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Section: Resultsmentioning

confidence: 99%

Comparative genomics of Shiga toxin encoding bacteriophages

et al. 2012

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“…The results shown in figure 2 are the calculated I-V characteristics of three different types of DNA sequences for short DNA strands of length L = 30 bps. The sequences considered are (i) the eukaryotic telomere based on repeats of the TTAGGG sequence as we discussed in section 1 [7,31], (ii) a random subsequence of bacteriophage λ-DNA [32,33] and (iii) a random subsequence of the DNA strand of the p53 gene [34,35]. The λ-DNA sequence has been studied previously as a typical example of a biological DNA sequence.…”

Section: Selection Of the Dna Sequencesmentioning

confidence: 99%

Robust signatures in the current–voltage characteristics of DNA molecules oriented between two graphene nanoribbon electrodes

et al. 2012

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In this work, we numerically calculate the electric current through three kinds of DNA sequences (telomeric, λ-DNA and p53-DNA) described by different heuristic models. A bias voltage is applied between two zigzag edged graphene contacts attached to the DNA segments, while a gate terminal modulates the conductance of the molecule. Calculation of the current is performed by integrating the transmission function (calculated using the lattice Green's function) over the range of energies allowed by the chemical potentials. We show that a telomeric DNA sequence, when treated as a quantum wire in the fully coherent low-temperature regime, works as an excellent semiconductor. Clear steps are apparent in the current-voltage curves of telomeric sequences and are present independent of length and sequence initialization at the contacts. We also find that the molecule-electrode coupling can drastically influence the 5

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“…These latter two phenomena operate by distinctly, conceptually different mechanisms (Hyman and Abedon, 2010), with superinfection exclusion a blockage as expressed by primary phages especially on the successful phage genome translocation into the adsorbed bacterium (Abedon, 1994) whereas superinfection immunity is a post genome-translocation mechanism by which subsequent secondary phage genetic contribution to infections is curtailed, though not always successfully (Fogg, et al, 2010). From the terms employed, we can view these phenomena literally as prevention (or exclusion) of secondarily adsorbing phages from superinfecting (superinfection exclusion) versus resistance (i.e., immunity) of a primary infection to the continuation of infection by secondary phages that nonetheless have successfully initiated superinfection (superinfection immunity).…”

Section: Parallel Secondary Infection-associated Phenomenamentioning

confidence: 99%

Bacteriophage secondary infection

Abedon

2015

Virol. Sin.

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Phages are credited with having been first described in what we now, officially, are commemorating as the 100(th) anniversary of their discovery. Those one-hundred years of phage history have not been lacking in excitement, controversy, and occasional convolution. One such complication is the concept of secondary infection, which can take on multiple forms with myriad consequences. The terms secondary infection and secondary adsorption, for example, can be used almost synonymously to describe virion interaction with already phage-infected bacteria, and which can result in what are described as superinfection exclusion or superinfection immunity. The phrase secondary infection also may be used equivalently to superinfection or coinfection, with each of these terms borrowed from medical microbiology, and can result in genetic exchange between phages, phage-on-phage parasitism, and various partial reductions in phage productivity that have been termed mutual exclusion, partial exclusion, or the depressor effect. Alternatively, and drawing from epidemiology, secondary infection has been used to describe phage population growth as that can occur during active phage therapy as well as upon phage contamination of industrial ferments. Here primary infections represent initial bacterial population exposure to phages while consequent phage replication can lead to additional, that is, secondary infections of what otherwise are not yet phage-infected bacteria. Here I explore the varying meanings and resultant ambiguity that has been associated with the term secondary infection. I suggest in particular that secondary infection, as distinctly different phenomena, can in multiple ways influence the success of phage-mediated biocontrol of bacteria, also known as, phage therapy.

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Bacteriophage Lambda: a Paradigm Revisited

Cited by 39 publications

References 24 publications

Comparative genomics of Shiga toxin encoding bacteriophages

Comparative genomics of Shiga toxin encoding bacteriophages

Robust signatures in the current–voltage characteristics of DNA molecules oriented between two graphene nanoribbon electrodes

Bacteriophage secondary infection

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