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. 2010 Mar 19;6(3):e1000716.
doi: 10.1371/journal.pcbi.1000716.

Emergence of spatial structure in cell groups and the evolution of cooperation

Carey D Nadell  1 , Kevin R Foster, João B Xavier
Affiliations

"VSports最新版本" Emergence of spatial structure in cell groups and the evolution of cooperation

Carey D Nadell et al. PLoS Comput Biol. .

Abstract

On its own, a single cell cannot exert more than a microscopic influence on its immediate surroundings VSports手机版. However, via strength in numbers and the expression of cooperative phenotypes, such cells can enormously impact their environments. Simple cooperative phenotypes appear to abound in the microbial world, but explaining their evolution is challenging because they are often subject to exploitation by rapidly growing, non-cooperative cell lines. Population spatial structure may be critical for this problem because it influences the extent of interaction between cooperative and non-cooperative individuals. It is difficult for cooperative cells to succeed in competition if they become mixed with non-cooperative cells, which can exploit the public good without themselves paying a cost. However, if cooperative cells are segregated in space and preferentially interact with each other, they may prevail. Here we use a multi-agent computational model to study the origin of spatial structure within growing cell groups. Our simulations reveal that the spatial distribution of genetic lineages within these groups is linked to a small number of physical and biological parameters, including cell growth rate, nutrient availability, and nutrient diffusivity. Realistic changes in these parameters qualitatively alter the emergent structure of cell groups, and thereby determine whether cells with cooperative phenotypes can locally and globally outcompete exploitative cells. We argue that cooperative and exploitative cell lineages will spontaneously segregate in space under a wide range of conditions and, therefore, that cellular cooperation may evolve more readily than naively expected. .

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Conflict of interest statement (VSports)

The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Dynamic simulations show that cell lineages segregate in a manner dependent on growth substrate availability.
Simulations began with a 1∶1 mixture of red and blue cells, where cell color served a neutral marker for lineage segregation. As bulk substrate concentration was decreased, we observed an increased propensity for cell lineages to segregate in space. This pattern held true under (A–C) surface growth and (D–F) radial growth conditions.
Figure 2
Figure 2. Lineage segregation in growing cell groups, visualized as a function of increasing cell group size.
We ran 50 simulations under each of the three substrate availability conditions shown in Figure 1. Each simulation was initiated with 10% blue cells and 90% red cells, and we calculated the segregation index relative to the blue cell line (Methods). Dark lines are means; shaded regions are running 95% confidence intervals.
Figure 3
Figure 3. The active layer of a cell group, illustrated for the surface growth condition.
Cells are colored according to their growth rate: green cells are growing and make up the cell group's active layer. Black cells have become inactive due to lack of available growth substrate. The left-hand panel illustrates the vertical profile of growth substrate concentration along the dashed blue line.
Figure 4
Figure 4. Lineage segregation within cell groups is inversely related to active layer depth.
The factors influencing cell group active layer depth were combined into a single dimensionless number, δ. This number was varied across 3 sets of simulations by independently altering μmax (maximum cell growth rate, red), Gbulk (bulk substrate availability, black), or DG (substrate diffusivity, blue). Cell groups were grown to 100 µm maximum height, and then the segregation index was calculated (filled circles are means, and bars denote 95% confidence intervals). The horizontal dotted line represents the final segregation index of simulations in which δ was infinitely large, allowing all cells to grow at the maximum rate at all times. The simulations show that cell lineage segregation is inversely related to active layer depth, independently of how active layer depth is altered.
Figure 5
Figure 5. Cooperation is favored as cell group active layer depth decreases and lineage segregation increases.
We examined competition between enzyme-secreting cells (cooperative, labeled blue) and non-secreting cells (exploitative, labeled red) under three different active layer conditions: δ = 10 (A, well mixed lineages), δ = 2 (B, lineage sectoring), and δ = 1 (C, lineage tower formation). Each empty black circle denotes the relative fitness of the cooperative cell type at the end of a single simulation (40 replicates per column). Sample images (drawn from simulations indicated by black arrows) are shown in the corner of each plot, along with concentration [g/L] profiles of the extracellular enzyme. (A) When cell lineages remain mixed, cooperative cells are always outgrown by exploitative cells. (B) When cell lineages segregate into sectors, there is a narrow range of enzyme production rates at which cooperative cells outcompete exploitative cells. (C) When lineages are strongly segregated into cell tower projections, there is a large range of enzyme production rates at which cooperative cells outcompete exploitative cells.
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References

    1. Pfeiffer T, Bonhoeffer S. An evolutionary scenario for the transition to undifferentiated multicellularity. Proc Natl Acad Sci USA. 2003;100:1095–1098. - PMC - PubMed
    1. Kreft JU. Biofilms promote altruism. Microbiol-SGM. 2004;150:2751–2760. - V体育ios版 - PubMed
    1. Kreft JU, Bonhoeffer S. The evolution of groups of cooperating bacteria and the growth rate versus yield trade-off. Microbiology. 2005;151:637–641. - V体育官网入口 - PubMed
    1. West SA, Diggle SP, Buckling A, Gardner A, Griffins AS. The social lives of microbes. Annu Rev Ecol Evol S. 2007;38:53–77.
    1. Stetler-Stevenson WG, Aznavoorian S, Liotta LA. Tumor cell interactions with the extracellular matrix during invasion and metastasis. Annu Rev Cell Biol. 1993;9:541–573. - PubMed

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