Coevolution in Bacterial-Plasmid Populations

Modi, Rajiv; Adams, Julian

doi:10.1111/j.1558-5646.1991.tb04336.x

Cited by 79 publications

(70 citation statements)

References 31 publications

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“…If the plasmid was introduced by a Salmonella 4,5,12:i:-strain into a K. pneumoniae strain, this could also account for a degree of pre-existing plasmid adaption to S348/11 but not B3791. This is supported by previous description of in vitro adaptation of a plasmid genome resulting in the amelioration of the fitness burden imposed upon its host (Modi & Adams, 1991).…”

Section: Discussionsupporting

confidence: 60%

Curing vector for IncI1 plasmids and its use to provide evidence for a metabolic burden of IncI1 CTX-M-1 plasmid pIFM3791 on Klebsiella pneumoniae

Martín

Thomas

Laing

et al. 2016

Journal of Medical Microbiology

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Using a sequence-based approach we previously identified an IncI1 CTX-M-1 plasmid, pIFM3791, on a single pig farm in the UK that was harboured by Klebsiella pneumoniae, Escherichia coli and Salmonella enterica serotype 4,5,12:i:-. To test the hypothesis that the plasmid had spread rapidly into these differing host bacteria we wished to assess whether the plasmid conferred a fitness advantage. To do this an IncI1 curing vector was constructed and used to displace the IncI1 CTX-M-1 plasmids from K. pneumoniae strain B3791 and several other unrelated IncI1-harbouring strains indicating the potential wider application of the curing vector. The IncI1 CTX-M-1 plasmid was reintroduced by conjugation into the cured K. pneumoniae strain and also a naturally IncI1 plasmid free S. enterica serotype 4,5,12:i:-, S348/11. Original, cured and complemented strains were tested for metabolic competence using Biolog technology and in competitive growth, association to mammalian cells and biofilm formation experiments. The plasmid-cured K. pneumoniae strain grew more rapidly than either the original plasmid-carrying strain or plasmidcomplemented strains in competition experiments. Additionally, the plasmid-cured strain was significantly better at respiring with L-sorbose as a carbon source and putrescine, g-amino-nbutyric acid, L-alanine and L-proline as nitrogen sources. By contrast, no differences in phenotype were found when comparing plasmid-harbouring and plasmid-free S. enterica S348/11. In conclusion, the IncI1 curing vector successfully displaced multiple IncI plasmids. The IncI1 CTX-M1 plasmid conferred a growth disadvantage upon K. pneumoniae, possibly by imposing a metabolic burden, the mechanism of which remains to be determined.

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Section: Discussionsupporting

confidence: 60%

Curing vector for IncI1 plasmids and its use to provide evidence for a metabolic burden of IncI1 CTX-M-1 plasmid pIFM3791 on Klebsiella pneumoniae

Martín

Thomas

Laing

et al. 2016

Journal of Medical Microbiology

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“…Control experiments showed that the mutation to arabinose resistance conferred a small selective disadvantage, s (relative reduction in growth rate; s = 1 -relative fitness [10]) during continuous culture in 1 x medium (s = 0.021 + 0.005 [see Fig. 2]), comparable to that reported earlier (s = 0.035 ± 0.009 [23]). The effect of the mutation varied slightly as the medium was varied so as to be essentially neutral in medium with the phosphate concentration reduced 10-fold.…”

supporting

confidence: 76%

Why does Escherichia coli have two primary pathways for synthesis of glutamate?

1994

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Escherichia coli has two primary pathways for glutamate synthesis. The glutamine synthetase-glutamate synthase pathway is known to be essential for synthesis at low ammonium concentrations and for regulation of the glutamine pool, but the necessity for glutamate dehydrogenase (GDH) has been uncertain. The results of competition experiments between the wild type and a GDH-deficient mutant during nutrient-limited growth and of direct enzyme measurements suggest that GDH is used in glutamate synthesis when the cell is limited for energy (and carbon) but ammonium and phosphate are present in excess, while the glutamine synthetase-glutamate synthase pathway is used when the cell is not under energy limitation. The use of alternative routes for glutamate synthesis implies that the energy cost of biosynthesis may be less when energy is limited than when energy is unlimited.

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“…It may therefore be possible that plasmid-encoded bacteriocin production may not impose a cost on the host relative to plasmid-free segregants, due to plasmid-host coevolution. In support of this, experiments investigating long-term relationships between colicin plasmids and their hosts have demonstrated a reduced plasmid burden relative to plasmid-free strains after 800 generations of plasmid-host association (Modi & Adams 1991). …”

Section: (A) Cost Of Bacteriocin Productionmentioning

confidence: 92%

“…It can be clearly seen that a number of factors may in fact reduce, eliminate, or perhaps reverse the costs associated with bacteriocin production and plasmid carriage. In particular, the likelihood of the coevolution of non-conjugative bacteriocin-encoding plasmids and their hosts to beneficial associations is high (Modi & Adams 1991 ;Lenski et al 1994). Furthermore, any of the bacteriocin burden-reducing features, or any combination of them, may act synergistically within a single bacteriocinproducing strain.…”

Section: Discussionmentioning

confidence: 99%

Selection and fitness in bacteriocin–producing bacteria

Dykes

Hastings

1997

Proc. R. Soc. Lond. B

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SUMMARYBacteriocins are proteinaceous anticompetitor molecules produced by bacteria against closely related species. A number of theoretical models have been used to explain experimental data that indicate high polymorphisms among bacteriocins and a frequency-dependent nature of selection for bacteriocinproducing strains. The majority of these experimental data were, however, obtained from investigations into the colicin group of bacteriocins produced by Gram-negative bacteria. The conclusions drawn from these models have been extrapolated to other bacteriocins and allelopathic compounds in general. Examination of more recent experimental investigations into the bacteriocins of Gram-positive bacteria indicate a lower degree of polymorphism and a less frequency-dependent mode of selection among these strains than among the colicin-producing strains. Here we examine these contradictions in the light of the assumptions and conclusions of the theoretical models and reported data. We show that fitness costs (as indicated by decreased relative maximum growth rate) associated with bacteriocin production may be much lower in many cases than is assumed in the present models. A lower fitness cost associated with bacteriocin production adequately explains the newer data from Gram-positive bacteria cited here, and indicates that extrapolation of existing models to all bacteriocins and other allelopathic compounds is not appropriate.

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Coevolution in Bacterial-Plasmid Populations

Cited by 79 publications

References 31 publications

Curing vector for IncI1 plasmids and its use to provide evidence for a metabolic burden of IncI1 CTX-M-1 plasmid pIFM3791 on Klebsiella pneumoniae

Curing vector for IncI1 plasmids and its use to provide evidence for a metabolic burden of IncI1 CTX-M-1 plasmid pIFM3791 on Klebsiella pneumoniae

Why does Escherichia coli have two primary pathways for synthesis of glutamate?

Selection and fitness in bacteriocin–producing bacteria

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