Dataset Information

Wrinkly-Spreader fitness in the two-dimensional agar plate microcosm: maladaptation, compensation and ecological success.

ABSTRACT: Bacterial adaptation to new environments often leads to the establishment of new genotypes with significantly altered phenotypes. In the Wrinkly Spreader (WS), ecological success in static liquid microcosms was through the rapid colonisation of the air-liquid interface by the production of a cellulose-based biofilm. Rapid surface spreading was also seen on agar plates, but in this two-dimensional environment the WS appears maladapted and rapidly reverts to the ancestral smooth (SM)-like colony genotype. In this work, the fitness of WS relative to SM in mixed colonies was found to be low, confirming the WS instability on agar plates. By examining defined WS mutants, the maladaptive characteristic was found to be the expression of cellulose. SM-like revertants had a higher growth rate than WS and no longer expressed significant amounts of cellulose, further confirming that the expression of this high-cost polymer was the basis of maladaptation and the target of compensatory mutation in developing colonies. However, examination of the fate of WS-founded populations in either multiple-colony or single mega-colony agar plate microcosms demonstrated that the loss of WS lineages could be reduced under conditions in which the rapid spreading colony phenotype could dominate nutrient and oxygen access more effectively than competing SM/SM-like genotypes. WS-like isolates recovered from such populations showed increased WS phenotype stability as well as changes in the degree of colony spreading, confirming that the WS was adapting to the two-dimensional agar plate microcosm.

SUBMITTER: Spiers AJ

PROVIDER: S-EPMC1939736 | biostudies-literature | 2007

REPOSITORIES: biostudies-literature

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Wrinkly-Spreader fitness in the two-dimensional agar plate microcosm: maladaptation, compensation and ecological success.

Spiers Andrew J AJ

PloS one 20070815 8

Bacterial adaptation to new environments often leads to the establishment of new genotypes with significantly altered phenotypes. In the Wrinkly Spreader (WS), ecological success in static liquid microcosms was through the rapid colonisation of the air-liquid interface by the production of a cellulose-based biofilm. Rapid surface spreading was also seen on agar plates, but in this two-dimensional environment the WS appears maladapted and rapidly reverts to the ancestral smooth (SM)-like colony g ...[more]

PMID: 17710140

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Project description:We illustrate an evolutionary host shift driven by increased fitness on a novel host, despite maladaptation to it in six separate host-adaptive traits. Here, local adaptation is defined as possession of traits that provide advantage in specific environmental contexts; thus individuals can have higher fitness in benign environments to which they are maladapted than in demanding environments to which they are well adapted. A population of the butterfly Euphydryas editha adapted to a long-lived, chemically well-defended host, Pedicularis, had traditionally been under natural selection to avoid the ephemeral, less-defended Collinsia. The lifespan of Collinsia was so short that it senesced before larvae entered diapause. After logging killed Pedicularis in clear-cut patches and controlled burning simultaneously extended Collinsia lifespan, insect fitness on Collinsia in clearings suddenly became higher than on Pedicularis in adjacent unlogged patches. Collinsia was rapidly colonized and preference for it evolved, but insects feeding on it retained adaptations to Pedicularis in alighting bias, two aspects of postalighting oviposition preference, dispersal bias, geotaxis, and clutch size, all acting as maladaptations to Collinsia. Nonetheless, populations boomed on Collinsia in clearings, creating sources that fed pseudosinks in unlogged patches where Pedicularis was still used. After c. 20 years, butterfly populations in clearings disappeared and the metapopulation reverted to Pedicularis-feeding. Here we show, via experimental manipulation of oviposition by local Pedicularis-adapted and imported Collinsia-adapted butterflies, that the highest survival at that time would have been from eggs laid in clearings by butterflies adapted to Collinsia. Second highest were locals on Pedicularis. In third place would have been locals on Collinsia in clearings, because local females maladaptively preferred senescent plants. Collinsia had been colonized despite maladaptation and, after successional changes, abandoned because of it. However, the abandoned Collinsia could still have provided the highest fitness, given appropriate adaptation. The butterflies had tumbled down an adaptive peak.

Project description:As a bioaerosol sampling standard, Andersen type impactor is widely used since its invention in 1950s, including the investigation of the anthrax attacks in the United States in 2001. However, its related problems such as impaction and desiccation stress as well as particle bounce have not been solved. Here, we improved its biological collection efficiencies by plating a mineral oil layer (100 µL) onto the agar plate. An Andersen six-stage sampler and a BioStage impactor were tested with mineral-oil-spread agar plates in collecting indoor and outdoor bacterial and fungal aerosols. The effects of sampling times (5, 10 and 20 min) were also studied using the BioStage impactor when sampling environmental bioaerosols as well as aerosolized Bacillus subtilis (G+) and Escherichia coli (G-). In addition, particle bounce reduction by mineral-oil-plate was also investigated using an optical particle counter (OPC). Experimental results revealed that use of mineral-oil-spread agar plate can substantially enhance culturable bioaerosol recoveries by Andersen type impactors (p-values<0.05). The recovery enhancement was shown to depend on bioaerosol size, type, sampling time and environment. In general, more enhancements (extra 20%) were observed for last stage of the Andersen six-stage samplers compared to the BioStage impactor for 10 min sampling. When sampling aerosolized B. subtilis, E. coli and environmental aerosols, the enhancement was shown to increase with increasing sampling time, ranging from 50% increase at 5 min to ?100% at 20 min. OPC results indicated that use of mineral oil can effectively reduce the particle bounce with an average of 66% for 10 min sampling. Our work suggests that enhancements for fungal aerosols were primarily attributed to the reduced impaction stress, while for bacterial aerosols reduced impaction, desiccation and particle bounce played major roles. The developed technology can readily enhance the agar-based techniques including those high volume portable samplers for bioaerosol monitoring.

Dataset Information

Wrinkly-Spreader fitness in the two-dimensional agar plate microcosm: maladaptation, compensation and ecological success.

Publications

Wrinkly-Spreader fitness in the two-dimensional agar plate microcosm: maladaptation, compensation and ecological success.

Similar Datasets

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