Experimental evolution of a microbial predator's ability to find prey

Hillesland, Kristina L.; Velicer, Gregory J.; Lenski, Richard E.

doi:10.1098/rspb.2008.1098

Cited by 36 publications

(46 citation statements)

References 57 publications

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“…Another approach to study predation is swarm assays, which indirectly measure prey killing and consumption (21,33). In contrast to the killing assay, this method allows predator fitness to be assessed.…”

Section: Vol 193 2011 Role Of Myxobacterial Antibiotics In Predatiomentioning

confidence: 99%

Antibiotic Production by Myxobacteria Plays a Role in Predation

et al. 2011

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Myxobacteria are predatory and are prolific producers of secondary metabolites. Here, we tested a hypothesized role that secondary metabolite antibiotics function as weapons in predation. To test this, a Myxococcus xanthus ⌬ta1 mutant, blocked in antibiotic TA (myxovirescin) production, was constructed. This TA ؊ mutant was defective in producing a zone of inhibition (ZOI) against Escherichia coli. This shows that TA is the major M. xanthus-diffusible antibacterial agent against E. coli. Correspondingly, the TA ؊ mutant was defective in E. coli killing. Separately, an engineered E. coli strain resistant to TA was shown to be resistant toward predation. Exogenous addition of spectinomycin, a bacteriostatic antibiotic, rescued the predation defect of the TA ؊ mutant. In contrast, against Micrococcus luteus the TA ؊ mutant exhibited no defect in ZOI or killing. Thus, TA plays a selective role on prey species. To extend these studies to other myxobacteria, the role of antibiotic corallopyronin production in predation was tested and also found to be required for Corallococcus coralloides killing on E. coli. Next, a role of TA production in myxobacterial fitness was assessed by measuring swarm expansion. Here, the TA ؊ mutant had a specific swarm rate reduction on prey lawns, and thus reduced fitness, compared to an isogenic TA ؉ strain. Based on these observations, we conclude that myxobacterial antibiotic production can function as a predatory weapon. To our knowledge, this is the first report to directly show a link between secondary metabolite production and predation.

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Section: Vol 193 2011 Role Of Myxobacterial Antibiotics In Predatiomentioning

confidence: 99%

Antibiotic Production by Myxobacteria Plays a Role in Predation

et al. 2011

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“…We control the selective environment and examine adaptations as they occur (12) and use microorganisms so that we can establish initially identical replicate populations and thus analyze the role of chance events in determining evolutionary outcomes (13). A similar approach has been used to rigorously examine various questions involving interactions between genotypes and species, including the evolution of predator-prey interactions (14,15), the evolution of intraspecific cooperation (16,17) and the ecological factors that stabilize commensal relationships against competition (7,18,19). The evolution of mutual cooperation between distinct species has not been addressed with experimental evolution, except to explore the relationships between mutualism and parasitism (20)(21)(22).…”

mentioning

confidence: 99%

Rapid evolution of stability and productivity at the origin of a microbial mutualism

Hillesland

Stahl²

2010

Proc. Natl. Acad. Sci. U.S.A.

220

236

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Mutualistic interactions are taxonomically and functionally diverse. Despite their ubiquity, however, the basic ecological and evolutionary processes underlying their origin and maintenance are poorly understood. A major reason for this is the lack of an experimentally tractable model system. We examine the evolution of an experimentally imposed obligate mutualism between sulfatereducing and methanogenic microorganisms that have no known history of previous interaction. Twenty-four independent pairings (cocultures) of the bacterium Desulfovibrio vulgaris and the archaeon Methanococcus maripaludis were established and followed for 300 community doublings in two environments, one allowing for the development of a heterogeneous distribution of resources and the other not. Evolved cocultures grew up to 80% faster and were up to 30% more productive (biomass yield per mole of substrate) than the ancestors. The evolutionary process was marked by periods of significant instability leading to extinction of two of the cocultures, but it resulted in more stable, efficient, and productive mutualisms for most replicated pairings. Comparisons of evolved cocultures with those assembled from one evolved mutualist and one ancestral mutualist showed that evolution of both species contributed to improved productivity. Surprisingly, however, overall improvements in growth rate and yield were less than the sum of the individual contributions, suggesting antagonistic interactions between mutations from the coevolved populations. Physical constraints on the transfer of metabolites in the evolution environment affected the evolution of M. maripaludis, but not of D. vulgaris. Together, these results demonstrate that challenges can imperil nascent obligate mutualisms and demonstrate the evolutionary responses that enable their persistence and future evolution.adaptation | experimental evolution | environmental heterogeneity | syntrophy | methanogenesis

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“…Experimental evolution has shown us much about the nature of sociality in M. xanthus. For example, when food was patchily distributed, the species evolved more efficient group hunting techniques (24). Under other circumstances, social cheaters can drive population crashes (23,25).…”

Section: Cooperation Writ Small: Microbesmentioning

confidence: 99%