Long-term experimental evolution decouples size and production costs in Escherichia coli

Abstract

Significance Populations of larger organisms should be more efficient in their resource use, but grow more slowly, than populations of smaller organisms. The relations between size, metabolism, and demography form the bedrock of metabolic theory, but most empirical tests have been correlative and indirect. Experimental lineages of Escherichia coli that evolved to make larger cells provide a unique opportunity to test how size, metabolism, and demography covary. Despite the larger cells having a relatively slower metabolism, they grow faster than smaller cells. They achieve this growth rate advantage by reducing the relative costs of producing their larger cells. That evolution can decouple the costs of production from size challenges a fundamental assumption about the connections between physiology and ecology.

Polyploidy impacts population growth and competition with diploids: multigenerational experiments reveal key life‐history trade‐offs

“…In contrast to population size, and in agreement with predictions from metabolic scaling theory (Marshall, 2022) and many individual‐level studies (Clo & Kolar, 2021), neopolyploid populations were more productive (final dry biomass) across all nutrient conditions. A least square mean comparison showed that neopolyploid populations accumulated 85% more biomass via current growth than diploids (Fig.…”

“…Since neopolyploid populations consisted of larger‐bodied fronds that were more productive regardless of nutrient treatment (Fig. 2), our results are consistent with metabolic size scaling rules for larger cells (Marshall, 2022) in which larger cells are metabolically more active but also more efficient. Although we expected that by providing higher nutrient supplies to neopolyploid populations, it would alleviate any growth disadvantage compared with their diploid progenitors, and we found that was not the case (Fig.…”

Resource allocation to cell envelopes and the scaling of bacterial growth rate

“…These are estimated in supplemental section S1.14, and reported in Table S1.9. The expected scaling of the steady-state metabolic rate is tested by using the measurements of the metabolic rate over the course of long-term experimental evolution in E. coli [48]. Note the cell volume measured in the original study was converted to S/V using the empirical scaling S = 2 πV 2 / 3 .…”

“…Left pane: Comparison of measured metabolic rate and theoretical expectation (Eq 31) for different values of nutritional capacity κ n inferred earlier. Points are metabolic rate measurements reported in [48]. Middle pane: the energy expenditure of protein and cell envelope synthesis.…”

Cell Sorting-Directed Selection of Bacterial Cells in Bigger Sizes Analyzed by Imaging Flow Cytometry during Experimental Evolution

“…Salmonella cells double the average length of swarmer cells and the number of flagella per cell during swarming, resulting in a significant increase in motor power [ 19 ]. Such morphological plasticity in bacteria indicates that bacterial morphology has a high potential for directed adaption in the laboratory under specific experimental conditions, such as Lenski’s long-term laboratory evolution [ 20 , 21 , 22 ] and our previous study where E. coli was adapted in an oleic acid vesicle (OAV)-rich medium [ 23 ].…”