@article {82602, title = {Resource plasticity-driven carbon-nitrogen budgeting enables specialization and division of labor in a clonal community }, journal = {Elife}, volume = {9}, year = {2020}, month = {09/2020}, abstract = {

Previously, we found that in glucose-limited Saccharomyces cerevisiae colonies, metabolic constraints drive cells into groups exhibiting gluconeogenic or glycolytic states. In that study, threshold amounts of trehalose - a limiting, produced carbon-resource, controls the emergence and self-organization of cells exhibiting the glycolytic state, serving as a carbon source that fuels glycolysis (Varahan et al., 2019). We now discover that the plasticity of use of a non-limiting resource, aspartate, controls both resource production and the emergence of heterogeneous cell states, based on differential metabolic budgeting. In gluconeogenic cells, aspartate is a carbon source for trehalose production, while in glycolytic cells using trehalose for carbon, aspartate is predominantly a nitrogen source for nucleotide synthesis. This metabolic plasticity of aspartate enables carbon-nitrogen budgeting, thereby driving the biochemical self-organization of distinct cell states. Through this organization, cells in each state exhibit true division of labor, providing growth/survival advantages for the whole community.

}, doi = {10.7554/eLife.57609 }, author = {Varahan, Sriram and Sinha, Vaibhhav and Walvekar, Adhish and Krishna, Sandeep and Laxman, Sunil} } @article {60325, title = {Metabolic constraints drive self-organization of specialized cell groups.}, journal = {Elife}, volume = {8}, year = {2019}, month = {2019 Jun 26}, abstract = {

How phenotypically distinct states in isogenic cell populations appear and stably co-exist remains unresolved. We find that within a mature, clonal yeast colony developing in low glucose, cells arrange into metabolically disparate cell groups. Using this system, we model and experimentally identify metabolic constraints sufficient to drive such self-assembly. Beginning in a uniformly gluconeogenic state, cells exhibiting a contrary, high pentose phosphate pathway activity state, spontaneously appear and proliferate, in a spatially constrained manner. Gluconeogenic cells in the colony produce and provide a resource, which we identify as trehalose. Above threshold concentrations of external trehalose, cells switch to the new metabolic state and proliferate. A self-organized system establishes, where cells in this new state are sustained by trehalose consumption, which thereby restrains other cells in the trehalose producing, gluconeogenic state. Our work suggests simple physico-chemical principles that determine how isogenic cells spontaneously self-organize into structured assemblies in complimentary, specialized states.

}, issn = {2050-084X}, doi = {10.7554/eLife.46735}, author = {Varahan, Sriram and Walvekar, Adhish and Sinha, Vaibhhav and Krishna, Sandeep and Laxman, Sunil} }