A sticky solution

David Gresham

doi:10.7554/elife.00655

Abstract

Selection favours single-celled mutants that stick together when a sugar needed for growth is in short supply, suggesting that multicellular life may have evolved as a by-product of selection for more efficient usage of resources.

Highlights

S. cerevisiae metabolizes the common sugar, sucrose, by first converting it to glucose and fructose outside the cell in a process called hydrolysis. This reaction is performed by a protein called invertase, which is secreted by the yeast cells, and the glucose and fructose are imported into the cells, where they are used to meet the metabolic requirements for growth
In a low sucrose environment, it is likely that the fraction of these products that diffuse away before they can be imported is high enough to mean that the local sugar concentration available to each yeast cell is insufficient for growth
The group of causal mutations included changes in a gene called ACE2, which encodes a protein required for completion of cell separation, and which results in a clumpy phenotype when defective (Gresham et al, 2006)

Summary

Introduction

Image Individual yeast cells (yellow) evolve to form multicellular clumps (magenta and green) Writing in eLife, John Koschwanez and Andrew Murray at Harvard University, and Kevin Foster at the University of Oxford, demonstrate that multicellularity can be selectively advantageous for microbes when sticking together solves a problem that cannot be solved by single-celled individuals (Koschwanez et al, 2013). S. cerevisiae metabolizes the common sugar, sucrose, by first converting it to glucose and fructose outside the cell in a process called hydrolysis.

Results

Conclusion