Publications by year
In Press
Lear L, Hesse E, Buckling A, Vos M (In Press). Copper Selects for Siderophore-Mediated Virulence in Pseudomonas Aeruginosa.
Lear L, Hesse E, Buckling A, Vos M (In Press). Copper selects for siderophore-mediated virulence in <i>Pseudomonas aeruginosa</i>.
Abstract:
Copper selects for siderophore-mediated virulence in Pseudomonas aeruginosa
AbstractIron is essential for almost all bacterial pathogens and consequently it is actively withheld by their hosts. However, the production of extracellular siderophores enables iron sequestration by pathogens, increasing their virulence. Another function of siderophores is extracellular detoxification of non-ferrous metals. Here, we experimentally link the detoxification and virulence roles of siderophores by testing whether the opportunistic pathogen Pseudomonas aeruginosa displays greater virulence after exposure to copper. To do this, we incubated P. aeruginosa under different environmentally relevant copper regimes for either two or twelve days. Subsequent growth in a copper-free environment removed phenotypic effects, before we quantified pyoverdine production (the primary siderophore produced by P. aeruginosa), and virulence using the Galleria mellonella infection model. Copper selected for increased pyoverdine production, which was positively correlated with virulence. This effect increased with time, such that populations incubated with high copper for twelve days were the most virulent. Replication of the experiment with a non-pyoverdine producing strain of P. aeruginosa demonstrated that pyoverdine production was largely responsible for the change in virulence. Therefore we here show a direct link between metal stress and bacterial virulence, highlighting another dimension of the detrimental effects of metal pollution on human health.
Abstract.
Hesse E, O’Brien S, Tromas N, Bayer F, Lujan A, Veen EV, Hodgson DJ, Buckling A (In Press). Ecological selection of siderophore-producing microbial taxa in response to heavy metal contamination.
Abstract:
Ecological selection of siderophore-producing microbial taxa in response to heavy metal contamination
AbstractSome microbial public goods can provide both individual and community-wide benefits, and are open to exploitation by non-producing species. One such example is the production of metal-detoxifying siderophores. Here, we investigate whether heavy metals select for increased siderophore production in natural microbial communities, or whether exploitation of this detoxifying effect reduces siderophore production. We show that the proportion of siderophore-producing taxa increases along a natural heavy metal gradient. A causal link between metal contamination and siderophore production was subsequently demonstrated in a microcosm experiment in compost, in which we observed changes in community composition towards taxa that produce relatively more siderophores following copper contamination. We confirmed the selective benefit of siderophores by showing that taxa producing large amount of siderophores suffered less growth inhibition in toxic copper. Our results suggest that ecological selection will favour siderophore-mediated decontamination, with important consequences for potential remediation strategies.AuthorshipEH, SOB, AL, DJH, EvV, AB conceived and designed the experiment. DJH provided new perspectives. EH, SOB, FB, AL collected the data. EH, FB, NT, DJH carried out the data analyses. EH & AB wrote the first draft of the manuscript, and all authors contributed substantially
to revisions.Data accessibility:Upon acceptance, data presented in the manuscript will be made available on Dryad.
Abstract.
Vos M, Andreani NA (In Press). Prokaryote genome fluidity is dependent on effective population size. ISME Journal
Klümper U, Maillard A, Hesse E, Bayer F, Houte SV, Longdon B, Gaze W, Buckling A (In Press). Short-term evolution under copper stress increases probability of plasmid uptake.
Abstract:
Short-term evolution under copper stress increases probability of plasmid uptake
AbstractUnderstanding plasmid transfer dynamics remains a key knowledge gap in the mitigation of antibiotic resistance gene spread. Direct effects of exposure to stressors on plasmid uptake are well monitored. However, it remains untested whether evolution of strains under stress conditions modulates subsequent plasmid uptake. Here, we evolved a compost derived microbial community for six weeks under copper stress and non-exposed control conditions. We then tested the ability of isolated clones from both treatments to take up the broad host range plasmid pKJK5 from anE.colidonor strain. Clones pre-adapted to copper displayed a significantly increased probability to be permissive towards the plasmid compared to those isolated from the control treatment. Further, increased phylogenetic distance to the donor strain was significantly and negatively correlated with plasmid uptake probabilities across both treatments.
Abstract.
Padfield D, Castledine M, Pennycook J, Hesse E, Buckling A (In Press). Short-term relative invader growth rate predicts long-term equilibrium proportion in a stable, coexisting microbial community.
Abstract:
Short-term relative invader growth rate predicts long-term equilibrium proportion in a stable, coexisting microbial community
AbstractThe ability of species to mutually invade from rare is the defining measure of species coexistence. However, it is unknown whether invasion growth rates predict any characteristic of long-term community dynamics. Here, we use a model five-species microbial community to investigate the link between short-term growth rate and long-term relative abundance. We manipulated diversity and tested the ability of species to coexist in different combinations. Across all diversity levels and species combinations, populations re-established from rare in 71 of 75 combinations and all combinations were stable in long-term culture. Moreover, short-term relative invader growth rate was positively associated with long-term equilibrium proportion, despite large variation in interactions between species and communities. This finding was confirmed using a modelling approach and suggests that the short-term invasion growth rate can predict long-term relative abundance within that community.
Abstract.
Lear L, Hesse E, Newsome L, Gaze W, Buckling A, Vos M (In Press). The effect of metal remediation on the virulence and antimicrobial resistance of the opportunistic pathogen <i>Pseudomonas aeruginosa</i>.
Abstract:
The effect of metal remediation on the virulence and antimicrobial resistance of the opportunistic pathogen Pseudomonas aeruginosa
AbstractMetal contamination poses both a direct threat to human health as well as an indirect threat through its potential to affect bacterial pathogens. Metals can not only co-select for antibiotic resistance, but also might affect pathogen virulence via increased siderophore production. Siderophores are extracellular compounds released to increase ferric iron uptake — a common limiting factor for pathogen growth within hosts – making them an important virulence factor. However, siderophores can also be positively selected for to detoxify non-ferrous metals, and consequently metal stress can potentially increase bacterial virulence. Anthropogenic methods to remediate environmental metal contamination commonly involve amendment with lime-containing materials, but whether this reduces in situ co-selection for antibiotic resistance and virulence remains unknown. Here, using microcosms containing metal-contaminated river water and sediment, we experimentally test whether metal remediation by liming reduces co-selection for these traits in the opportunistic pathogen Pseudomonas aeruginosa embedded within a natural microbial community. To test for the effects of environmental structure, which can impact siderophore production, microcosms were incubated under either static or shaking conditions. Evolved P. aeruginosa populations had greater fitness in the presence of toxic concentrations of copper than the ancestral strain, but this effect was reduced in the limed treatments. Evolved P. aeruginosa populations showed increased resistance to the clinically-relevant antibiotics apramycin, cefotaxime, and trimethoprim, regardless of lime addition or environmental structure. Although we found virulence to be significantly associated with siderophore production, neither virulence nor siderophore production significantly differed between the four treatments. We therefore demonstrate that although remediation via liming reduced the strength of selection for metal resistance mechanisms, it did not mitigate metal-imposed selection for antibiotic resistance or virulence in P. aeruginosa. Consequently, metal-contaminated environments may select for antibiotic resistance and virulence traits even when treated with lime.Graphical abstract
Abstract.
Vos M, Sibleyras L, Lo LK, Hesse E, Gaze W, Klümper U (In Press). Zinc can counteract selection for ciprofloxacin resistance.
Abstract:
Zinc can counteract selection for ciprofloxacin resistance
AbstractAntimicrobial resistance (AMR) has emerged as one of the most pressing global threats to public health. AMR evolution occurs in the clinic but also in the environment, where low concentrations of antibiotics and heavy metals can respectively select and co-select for resistance. While the selective potential for AMR of both antibiotics and metals is increasingly well-characterized, studies exploring the combined effect of both types of selective agents are rare. It has previously been demonstrated that fluoroquinolone antibiotics such as ciprofloxacin can chelate metal ions. To investigate how ciprofloxacin resistance is affected by the presence of metals, we quantified selection dynamics between a ciprofloxacin-susceptible and an isogenic ciprofloxacin-resistantEscherichia coliMG1655 strain across a gradient of ciprofloxacin concentrations in the presence and absence of Zinc cations (Zn2+). The minimal selective concentration (MSC) for ciprofloxacin resistance significantly increased up to 5-fold in the presence of Zn2+. No such effect on the MSC was found for gentamicin, an antibiotic not known to chelate zinc cations. Environmental pollution usually consists of complex mixtures of antimicrobial agents. Our findings highlight the importance of taking antagonistic as well as additive or synergistic interactions between different chemical compounds into account when considering their effect on bacterial resistance evolution.Graphical abstractOne sentence summaryThe minimal selective concentration for a ciprofloxacin resistantE. colistrain increases up to 5-fold in the presence of Zinc cations.
Abstract.
2023
Lear L, Padfield D, Hesse E, Kay S, Buckling A, Vos M (2023). Copper reduces the virulence of bacterial communities at environmentally relevant concentrations.
Kelbrick M, Hesse E, O' Brien S (2023). Cultivating antimicrobial resistance: how intensive agriculture ploughs the way for antibiotic resistance.
Microbiology (Reading),
169(8).
Abstract:
Cultivating antimicrobial resistance: how intensive agriculture ploughs the way for antibiotic resistance.
Antimicrobial resistance (AMR) is a growing threat to public health, global food security and animal welfare. Despite efforts in antibiotic stewardship, AMR continues to rise worldwide. Anthropogenic activities, particularly intensive agriculture, play an integral role in the dissemination of AMR genes within natural microbial communities - which current antibiotic stewardship typically overlooks. In this review, we examine the impact of anthropogenically induced temperature fluctuations, increased soil salinity, soil fertility loss, and contaminants such as metals and pesticides on the de novo evolution and dissemination of AMR in the environment. These stressors can select for AMR - even in the absence of antibiotics - via mechanisms such as cross-resistance, co-resistance and co-regulation. Moreover, anthropogenic stressors can prime bacterial physiology against stress, potentially widening the window of opportunity for the de novo evolution of AMR. However, research to date is typically limited to the study of single isolated bacterial species - we lack data on how intensive agricultural practices drive AMR over evolutionary timescales in more complex microbial communities. Furthermore, a multidisciplinary approach to fighting AMR is urgently needed, as it is clear that the drivers of AMR extend far beyond the clinical environment.
Abstract.
Author URL.
Sierocinski P, Bayer F, Hesse E, Buckling A (2023). Rapid evolution drives increased function of a complex microbial community.
Lear L, Hesse E, Newsome L, Gaze W, Buckling A, Vos M (2023). The effect of metal remediation on the virulence and antimicrobial resistance of the opportunistic pathogen <i>Pseudomonas aeruginosa</i>.
Evolutionary Applications,
16(7), 1377-1389.
Abstract:
The effect of metal remediation on the virulence and antimicrobial resistance of the opportunistic pathogen Pseudomonas aeruginosa
AbstractAnthropogenic metal pollution can result in co‐selection for antibiotic resistance and potentially select for increased virulence in bacterial pathogens. Metal‐polluted environments can select for the increased production of siderophore molecules to detoxify non‐ferrous metals. However, these same molecules also aid the uptake of ferric iron, a limiting factor for within‐host pathogen growth, and are consequently a virulence factor. Anthropogenic methods to remediate environmental metal contamination commonly involve amendment with lime‐containing materials. However, whether this reduces in situ co‐selection for antibiotic resistance and siderophore‐mediated virulence remains unknown. Here, using microcosms containing non‐sterile metal‐contaminated river water and sediment, we test whether liming reduces co‐selection for these pathogenicity traits in the opportunistic pathogen Pseudomonas aeruginosa. To account for the effect of environmental structure, which is known to impact siderophore production, microcosms were incubated under either static or shaking conditions. Evolved P. aeruginosa populations had greater fitness in the presence of toxic concentrations of copper than the ancestral strain and showed increased resistance to the clinically relevant antibiotics apramycin, cefotaxime and trimethoprim, regardless of lime addition or environmental structure. Although we found virulence to be significantly associated with siderophore production, neither virulence nor siderophore production significantly differed between the four treatments. Furthermore, liming did not mitigate metal‐imposed selection for antibiotic resistance or virulence in P. aeruginosa. Consequently, metal‐contaminated environments may select for antibiotic resistance and virulence traits even when treated with lime.
Abstract.
2022
Lear L, Hesse E, Buckling A, Vos M (2022). Copper selects for siderophore-mediated virulence in Pseudomonas aeruginosa.
Newbury A, Dawson B, Klümper U, Hesse E, Castledine M, Fontaine C, Buckling A, Sanders D (2022). Fitness effects of plasmids shape the structure of bacteria-plasmid interaction networks.
Proc Natl Acad Sci U S A,
119(22).
Abstract:
Fitness effects of plasmids shape the structure of bacteria-plasmid interaction networks.
Antimicrobial resistance (AMR) genes are often carried on broad host range plasmids, and the spread of AMR within microbial communities will therefore depend on the structure of bacteria–plasmid networks. Empirical and theoretical studies of ecological interaction networks suggest that network structure differs between communities that are predominantly mutualistic versus antagonistic, with the former showing more generalized interactions (i.e. species interact with many others to a similar extent). This suggests that mutualistic bacteria–plasmid networks—where antibiotics are present and plasmids carry AMR genes—will be more generalized than antagonistic interactions, where plasmids do not confer benefits to their hosts. We first develop a simple theory to explain this link: fitness benefits of harboring a mutualistic symbiont promote the spread of the symbiont to other species. We find support for this theory using an experimental bacteria–symbiont (plasmid) community, where the same plasmid can be mutualistic or antagonistic depending on the presence of antibiotics. This short-term and parsimonious mechanism complements a longer-term mechanism (coevolution and stability) explaining the link between mutualistic and antagonistic interactions and network structure.
Abstract.
Author URL.
Luján AM, Paterson S, Hesse E, Sommer LM, Marvig RL, Sharma MD, Alseth EO, Ciofu O, Smania AM, Molin S, et al (2022). Polymicrobial infections can select against Pseudomonas aeruginosa mutators because of quorum-sensing trade-offs.
Nature Ecology and Evolution,
6(7), 979-988.
Abstract:
Polymicrobial infections can select against Pseudomonas aeruginosa mutators because of quorum-sensing trade-offs
Bacteria with increased mutation rates (mutators) are common in chronic infections and are associated with poorer clinical outcomes, especially in the case of Pseudomonas aeruginosa infecting cystic fibrosis (CF) patients. There is, however, considerable between-patient variation in both P. aeruginosa mutator frequency and the composition of co-infecting pathogen communities. We investigated whether community context might affect selection of mutators. Using an in vitro CF model community, we show that P. aeruginosa mutators were favoured in the absence of other species but not in their presence. This was because there were trade-offs between adaptation to the biotic and abiotic environments (for example, loss of quorum sensing and associated toxin production was beneficial in the latter but not the former in our in vitro model community) limiting the evolvability advantage of an elevated mutation rate. Consistent with a role of co-infecting pathogens selecting against P. aeruginosa mutators in vivo, we show that the mutation frequency of P. aeruginosa population was negatively correlated with the frequency and diversity of co-infecting bacteria in CF infections. Our results suggest that co-infecting taxa can select against P. aeruginosa mutators, which may have potentially beneficial clinical consequences.
Abstract.
2021
Lear L, Hesse E, Buckling A, Vos M (2021). Copper Selects for Siderophore-Mediated Virulence in Pseudomonas Aeruginosa.
Hesse E, O'Brien S, Lujan AM, Sanders D, Bayer F, Veen EM, Hodgson DJ, Buckling A (2021). Stress causes interspecific facilitation within a compost community.
ECOLOGY LETTERS,
24(10), 2169-2177.
Author URL.
2020
Lear L, Hesse E, Shea K, Buckling A (2020). Disentangling the mechanisms underpinning disturbance-mediated invasion.
Proceedings of the Royal Society B: Biological Sciences,
287(1919).
Abstract:
Disentangling the mechanisms underpinning disturbance-mediated invasion
Disturbances can play a major role in biological invasions: by destroying biomass, they alter habitat and resource abundances. Previous field studies suggest that disturbance-mediated invader success is a consequence of resource influxes, but the importance of other potential covarying causes, notably the opening up of habitats, have yet to be directly tested. Using experimental populations of the bacterium Pseudomonas fluorescens, we determined the relative importance of disturbance-mediated habitat opening and resource influxes, plus any interaction between them, for invader success of two ecologically distinct morphotypes. Resource addition increased invasibility, while habitat opening had little impact and did not interact with resource addition. Both invaders behaved similarly, despite occupying different ecological niches in the microcosms. Treatment also affected the composition of the resident population, which further affected invader success. Our results provide experimental support for the observation that resource input is a key mechanism through which disturbance increases invasibility.
Abstract.
Padfield D, Vujakovic A, Paterson S, Griffiths R, Buckling A, Hesse E (2020). Evolution of diversity explains the impact of pre-adaptation of a focal species on the structure of a natural microbial community.
ISME J,
14(11), 2877-2889.
Abstract:
Evolution of diversity explains the impact of pre-adaptation of a focal species on the structure of a natural microbial community.
Rapid within-species evolution can alter community structure, yet the mechanisms underpinning this effect remain unknown. Populations that rapidly evolve large amounts of phenotypic diversity are likely to interact with more species and have the largest impact on community structure. However, the evolution of phenotypic diversity is, in turn, influenced by the presence of other species. Here, we investigate how microbial community structure changes as a consequence of rapidly evolved within-species diversity using Pseudomonas fluorescens as a focal species. Evolved P. fluorescens populations showed substantial phenotypic diversification in resource-use (and correlated genomic change) irrespective of whether they were pre-adapted in isolation or in a community context. Manipulating diversity revealed that more diverse P. fluorescens populations had the greatest impact on community structure, by suppressing some bacterial taxa, but facilitating others. These findings suggest that conditions that promote the evolution of high within-population diversity should result in a larger impact on community structure.
Abstract.
Author URL.
Stilwell P, O'Brien S, Hesse E, Lowe C, Gardner A, Buckling A (2020). Resource heterogeneity and the evolution of public goods cooperation.
EVOLUTION LETTERS,
4(2), 155-163.
Author URL.
Vos M, Sibleyras L, Lo LK, Hesse E, Gaze W, Klümper U (2020). Zinc can counteract selection for ciprofloxacin resistance.
FEMS Microbiol Lett,
367(3).
Abstract:
Zinc can counteract selection for ciprofloxacin resistance.
Antimicrobial resistance (AMR) has emerged as one of the most pressing threats to public health. AMR evolution occurs in the clinic but also in the environment, where antibiotics and heavy metals can select and co-select for AMR. While the selective potential of both antibiotics and metals is increasingly well-characterized, experimental studies exploring their combined effects on AMR evolution are rare. It has previously been demonstrated that fluoroquinolone antibiotics such as ciprofloxacin can chelate metal ions. To investigate how ciprofloxacin resistance is affected by the presence of metals, we quantified selection dynamics between a ciprofloxacin-susceptible and a ciprofloxacin-resistant Escherichia coli strain across a gradient of ciprofloxacin concentrations in presence and absence of zinc. The presence of zinc reduced growth of both strains, while ciprofloxacin inhibited exclusively the susceptible one. When present in combination zinc retained its inhibitory effect, while ciprofloxacin inhibition of the susceptible strain was reduced. Consequently, the minimal selective concentration for ciprofloxacin resistance increased up to five-fold in the presence of zinc. Environmental pollution usually comprises complex mixtures of antimicrobial agents. In addition to the usual focus on additive or synergistic interactions in complex selective mixtures, our findings highlight the importance of antagonistic selective interactions when considering resistance evolution.
Abstract.
Author URL.
2019
Hesse E, Padfield D, Bayer F, van Veen EM, Bryan CG, Buckling A (2019). Anthropogenic remediation of heavy metals selects against natural microbial remediation.
Proc Biol Sci,
286(1905).
Abstract:
Anthropogenic remediation of heavy metals selects against natural microbial remediation.
In an era of unprecedented environmental change, there have been increasing ecological and global public health concerns associated with exposure to anthropogenic pollutants. While there is a pressing need to remediate polluted ecosystems, human intervention might unwittingly oppose selection for natural detoxification, which is primarily carried out by microbes. We test this possibility in the context of a ubiquitous chemical remediation strategy aimed at targeting metal pollution: the addition of lime-containing materials. Here, we show that raising pH by liming decreased the availability of toxic metals in acidic mine-degraded soils, but as a consequence selected against microbial taxa that naturally remediate soil through the production of metal-binding siderophores. Our results therefore highlight the crucial need to consider the eco-evolutionary consequences of human environmental strategies on microbial ecosystem services and other traits.
Abstract.
Author URL.
Hesse E, O’Brien S, Luján AM, Bayer F, van Veen EM, Hodgson DJ, Buckling A (2019). Interspecific social interactions shape public goods production in natural microbial communities.
Hernandez RJ, Hesse E, Dowling AJ, Coyle NM, Feil EJ, Gaze WH, Vos M (2019). Using the wax moth larva Galleria mellonella infection model to detect emerging bacterial pathogens. PeerJ, 6
2018
Hesse E, O'Brien S, Tromas N, Bayer F, Luján AM, van Veen EM, Hodgson DJ, Buckling A (2018). Ecological selection of siderophore-producing microbial taxa in response to heavy metal contamination.
Ecol Lett,
21(1), 117-127.
Abstract:
Ecological selection of siderophore-producing microbial taxa in response to heavy metal contamination.
Some microbial public goods can provide both individual and community-wide benefits, and are open to exploitation by non-producing species. One such example is the production of metal-detoxifying siderophores. Here, we investigate whether conflicting selection pressures on siderophore production by heavy metals - a detoxifying effect of siderophores, and exploitation of this detoxifying effect - result in a net increase or decrease. We show that the proportion of siderophore-producing taxa increases along a natural heavy metal gradient. A causal link between metal contamination and siderophore production was subsequently demonstrated in a microcosm experiment in compost, in which we observed changes in community composition towards taxa that produce relatively more siderophores following copper contamination. We confirmed the selective benefit of siderophores by showing that taxa producing large amounts of siderophore suffered less growth inhibition in toxic copper. Our results suggest that ecological selection will favour siderophore-mediated decontamination, with important consequences for potential remediation strategies.
Abstract.
Author URL.
Hesse E, Hodgson DJ, de Jong TJ (2018). Glucosinolates promote initial population establishment of feral oilseed rape.
O'Brien S, Hesse E, Luján A, Hodgson DJ, Gardner A, Buckling A (2018). No effect of intraspecific relatedness on public goods cooperation in a complex community.
Evolution,
72(5), 1165-1173.
Abstract:
No effect of intraspecific relatedness on public goods cooperation in a complex community.
Many organisms-notably microbes-are embedded within complex communities where cooperative behaviors in the form of excreted public goods can benefit other species. Under such circumstances, intraspecific interactions are likely to be less important in driving the evolution of cooperation. We first illustrate this idea with a simple theoretical model, showing that relatedness-the extent to which individuals with the same cooperative alleles interact with each other-has a reduced impact on the evolution of cooperation when public goods are shared between species. We test this empirically using strain of Pseudomonas aeruginosa that vary in their production of metal-chelating siderophores in copper contaminated compost (an interspecific public good). We show that nonsiderophore producers grow poorly relative to producers under high relatedness, but this cost can be alleviated by the presence of the isogenic producer (low relatedness) and/or the compost microbial community. Hence, relatedness can become unimportant when public goods provide interspecific benefits.
Abstract.
Author URL.
Zhao X-F, Buckling A, Zhang Q-G, Hesse E (2018). Specific adaptation to strong competitors can offset the negative effects of population size reductions.
Proc Biol Sci,
285(1875).
Abstract:
Specific adaptation to strong competitors can offset the negative effects of population size reductions.
Competition plays a crucial role in determining adaptation of species, yet we know little as to how adaptation is affected by the strength of competition. On the one hand, strong competition typically results in population size reductions, which can hamper adaptation owing to a shortage of beneficial mutations; on the other hand, specificity of adaptation to competitors may offset the negative evolutionary consequences of such population size effects. Here, we investigate how competition strength affects population fitness in the bacterium Pseudomonas fluorescens Our results demonstrate that strong competition constrains adaptation of focal populations, which can be partially explained by population size reductions. However, fitness assays also reveal specific adaptation of focal populations to particular competitors varying in competitive ability. Additionally, this specific adaptation can offset the negative effects of competitor-mediated population size reductions under strong competition. Our study, therefore, highlights the importance of opposing effects of strong competition on species adaptation, which may lead to different outcomes of colonization under intense and relaxed competitive environments in the context of population dispersal.
Abstract.
Author URL.
Hernandez RJ, Hesse E, Dowling AJ, Coyle NM, Feil EJ, Gaze WH, Vos M (2018). Using the Wax moth larva Galleria mellonella infection model to detect emerging bacterial pathogens.
2016
Hesse E, Buckling A (2016). Host population bottlenecks drive parasite extinction during antagonistic coevolution.
Evolution,
70(1), 235-240.
Abstract:
Host population bottlenecks drive parasite extinction during antagonistic coevolution.
Host-parasite interactions are often characterized by large fluctuations in host population size, and we investigated how such host bottlenecks affected coevolution between a bacterium and a virus. Previous theory suggests that host bottlenecks should provide parasites with an evolutionary advantage, but instead we found that phages were rapidly driven to extinction when coevolving with hosts exposed to large genetic bottlenecks. This was caused by the stochastic loss of sensitive bacteria, which are required for phage persistence and infectivity evolution. Our findings emphasize the importance of feedbacks between ecological and coevolutionary dynamics, and how this feedback can qualitatively alter coevolutionary dynamics.
Abstract.
Author URL.
Vos M, Mcleman, Buckling, Hesse, Sierocinski, Johnsen PJ, Perron GG, Huelter N (2016). No effect of natural transformation on the evolution of resistance to bacteriophages in the Acinetobacter baylyi model system. Scientific Reports
2015
Hesse E, Best A, Boots M, Hall AR, Buckling A (2015). Spatial heterogeneity lowers rather than increases host-parasite specialization.
Journal of Evolutionary Biology,
28(9), 1682-1690.
Abstract:
Spatial heterogeneity lowers rather than increases host-parasite specialization
Abiotic environmental heterogeneity can promote the evolution of diverse resource specialists, which in turn may increase the degree of host-parasite specialization. We coevolved Pseudomonas fluorescens and lytic phage ϕ{symbol}2 in spatially structured populations, each consisting of two interconnected subpopulations evolving in the same or different nutrient media (homogeneous and heterogeneous environments, respectively). Counter to the normal expectation, host-parasite specialization was significantly lower in heterogeneous compared with homogeneous environments. This result could not be explained by dispersal homogenizing populations, as this would have resulted in the heterogeneous treatments having levels of specialization equal to or greater than that of the homogeneous environments. We argue that selection for costly generalists is greatest when the coevolving species are exposed to diverse environmental conditions and that this can provide an explanation for our results. A simple coevolutionary model of this process suggests that this can be a general mechanism by which environmental heterogeneity can reduce rather than increase host-parasite specialization.
Abstract.
Hesse E, Best A, Boots M, Hall AR, Buckling A (2015). Spatial heterogeneity lowers rather than increases host-parasite specialization.
J Evol Biol,
28(9), 1682-1690.
Abstract:
Spatial heterogeneity lowers rather than increases host-parasite specialization.
Abiotic environmental heterogeneity can promote the evolution of diverse resource specialists, which in turn may increase the degree of host-parasite specialization. We coevolved Pseudomonas fluorescens and lytic phage ϕ2 in spatially structured populations, each consisting of two interconnected subpopulations evolving in the same or different nutrient media (homogeneous and heterogeneous environments, respectively). Counter to the normal expectation, host-parasite specialization was significantly lower in heterogeneous compared with homogeneous environments. This result could not be explained by dispersal homogenizing populations, as this would have resulted in the heterogeneous treatments having levels of specialization equal to or greater than that of the homogeneous environments. We argue that selection for costly generalists is greatest when the coevolving species are exposed to diverse environmental conditions and that this can provide an explanation for our results. A simple coevolutionary model of this process suggests that this can be a general mechanism by which environmental heterogeneity can reduce rather than increase host-parasite specialization.
Abstract.
Author URL.
2013
de Jong TJ, Isanta MT, Hesse E (2013). Comparison of the crop species Brassica napus and wild B. rapa: characteristics relevant for building up a persistent seed bank in the soil. Seed Science Research, 23(3), 169-179.
2012
de Jong TJ, Hesse E (2012). Selection against hybrids in mixed populations of Brassica rapa and Brassica napus: model and synthesis. New Phytologist, 194(4), 1134-1142.
2011
Hesse E, Pannell JR (2011). Density‐dependent pollen limitation and reproductive assurance in a wind‐pollinated herb with contrasting sexual systems. Journal of Ecology, 99(6), 1531-1539.
Hesse E, Pannell JR (2011). Sexual Dimorphism in Androdioecious Mercurialis annua , a Wind-Pollinated Herb. International Journal of Plant Sciences, 172(1), 49-59.
Hesse E, Pannell JR (2011). Sexual dimorphism in a dioecious population of the wind-pollinated herb Mercurialis annua: the interactive effects of resource availability and competition. Annals of Botany, 107(6), 1039-1045.
2008
Hesse E, Rees M, Müller-Schärer H (2008). Life-history variation in contrasting habitats: flowering decisions in a clonal perennial herb (Veratrum album). The American Naturalist, 172(5), 196-213.
2006
Hesse E, Rees M, Müller-Schärer H (2006). Seed bank persistence of clonal weeds in contrasting habitats: implications for control. Plant Ecology, 190(2), 233-243.
