Frequency-Dependent Selection in Light of Phage Exposure

Abedon, Stephen T.

doi:10.1007/978-3-030-94309-7_24

Cited by 2 publications

(2 citation statements)

References 35 publications

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“…Something along the same lines has been described for the most abundant picocyanobacterium Prochlorococcus , and its phages (Avrani et al, 2011; Coleman et al, 2006; Schwartz and Lindell, 2017). The O-chain is a major target for phage receptor-binding proteins and thus there are two potential phage-related explanations for its diversity-arms-race and density-dependent negative selection (Abedon, 2022; Rodriguez-Valera et al, 2009). In the latter, increased predation on abundant OBC-types, maintains a large diversity of receptors, distributing the predation pressure among many.…”

Section: Discussionmentioning

confidence: 99%

Large diversity in the O-chain biosynthetic cluster within populations of Pelagibacterales

Haro-Moreno,

López-Pérez,

Molina-Pardines

et al. 2024

Preprint

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In this study, we have used single-amplified genomes (SAGs) and long-read metagenomics to examine the intrapopulation diversity of the O-chain polysaccharide biosynthesis cluster (OBC) in marine bacteria of the Pelagibacterales order. OBCs are notorious for their diversity and have been used to type strains in pathogens and saprophytes, but their patterns of variation in free-living bacteria are little known. We found that, for these major photoheterotrophic bacteria, the diversity is comparable to that of saprophytes, such as Enterobacteriales i.e. nearly each strain carries a different OBC involved in its synthesis. Therefore, different OBCs had completely different gene complements, as they had few ortholog genes. However, although OBC inheritance was largely vertical, the existence of some shared clusters allowed a comparative analysis that showed that the cluster diverges along with the genome, indicative of old horizontal gene transfer (HGT). Only 14 cases of recent HGT were detected and they happened independently of taxonomy or location. Although the O-chain is a major phage receptor in Gram-negative bacteria, the exchange of the complete cluster seems to play a minor role in arms-race evolution. However, dN/dS was significantly larger for the genes in the OBC than for the whole genome so OBC genes appear to be more variable. By long-read metagenomics, we could detect 380 different OBCs in a single sampling site in the Mediterranean. A single population (single species and sample) of the endemic Ia.3/VII genomospecies had a set of 158 OBCs of which 130 were different.

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Section: Discussionmentioning

confidence: 99%

Large diversity in the O-chain biosynthetic cluster within populations of Pelagibacterales

Haro-Moreno,

López-Pérez,

Molina-Pardines

et al. 2024

Preprint

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“…Perhaps related to these latter ideas is the reported “Explosive” ejection of antibacterial tailocins, i.e., bacteriocins consisting of phage tail-like structures lacking in virion heads, as generated by producing bacteria upon the latter’s lysis [ 72 ], as indeed could apply to whole phages as well. These tails perhaps may serve as physically more effective projectiles for targeting bacteria found in adjacent, biofilm matrix-encased competitor microcolonies than could instead whole phages with somewhat wider heads [ 73 ]. Specifically, tailocins may be able to not just more effectively reach neighboring, competing biofilms via their explosive discharge, but also might then be able to more effectively penetrate those biofilms than whole phage virions, i.e., due to the slimmer dimensions of phage tails relative to those of phage heads.…”

Section: Reductions In Rates Of Virion Diffusionmentioning

confidence: 99%

Bacteriophage Adsorption: Likelihood of Virion Encounter with Bacteria and Other Factors Affecting Rates

Abedon

2023

Antibiotics

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For ideal gasses, the likelihood of collision of two molecules is a function of concentrations as well as environmental factors such as temperature. This too is the case for particles diffusing within liquids. Two such particles are bacteria and their viruses, the latter called bacteriophages or phages. Here, I review the basic process of predicting the likelihoods of phage collision with bacteria. This is a key step governing rates of phage-virion adsorption to their bacterial hosts, thereby underlying a large fraction of the potential for a given phage concentration to affect a susceptible bacterial population. Understanding what can influence those rates is very relevant to appreciating both phage ecology and the phage therapy of bacterial infections, i.e., where phages are used to augment or replace antibiotics; so too adsorption rates are highly important for predicting the potential for phage-mediated biological control of environmental bacteria. Particularly emphasized here, however, are numerous complications on phage adsorption rates beyond as dictated by the ideals of standard adsorption theory. These include movements other than due to diffusion, various hindrances to diffusive movement, and the influence of assorted heterogeneities. Considered chiefly are the biological consequences of these various phenomena rather than their mathematical underpinnings.

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Frequency-Dependent Selection in Light of Phage Exposure

Cited by 2 publications

References 35 publications

Large diversity in the O-chain biosynthetic cluster within populations of Pelagibacterales

Large diversity in the O-chain biosynthetic cluster within populations of Pelagibacterales

Bacteriophage Adsorption: Likelihood of Virion Encounter with Bacteria and Other Factors Affecting Rates

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