In:
eLife, eLife Sciences Publications, Ltd, Vol. 4 ( 2015-10-26)
Abstract:
Life is sustained by an array of chemical reactions that is collectively referred to as metabolism. Some of these reactions break down complex substances to release energy and vital compounds, while others make new molecules from smaller building blocks. Bacterial communities are regularly composed of heterogeneous species, several of which have lost one or more essential metabolic pathways. Nevertheless, these cells can still survive by making use of metabolic products released by their neighbouring cells. Yeast are single-celled fungi that also form colonies and, as eukaryotes, they possess cells that are more similar to our own. However, in the laboratory, complementary metabolically deficient yeast cells do not survive when mixed together. It was presumed this is because yeast cells make only enough of each essential metabolite for themself, and so can’t replace those that are missing from their neighbouring cells. Campbell et al. now challenge this view by finding that yeast cells release a variety of metabolites, they use these released metabolites in preference to making their own, and possess the capacity to grow on the basis of a non-cell-autonomous metabolism. This discovery came with the design of a new experimental test to study metabolite exchange interactions. This method uses yeast cells that have one or more of their own metabolic genes disabled, and instead have a copy of these genes on small circular DNA 'mini-chromosomes' (called plasmids). The gene on the plasmid can compensate for the yeast having its own gene missing, and allows the cell to still make the metabolic product it needs to survive. However, as a single cell divides to form a colony, cells randomly lose these plasmids, leaving some of the cells deficient for a particular metabolite. These cells can only survive if the other cells in the colony export the missing metabolite in the quantity needed for growth. Using this test, Campbell et al. found that yeast cells can export missing metabolites at levels needed to sustain these emerging metabolic mutants. Additionally, these yeast communities could grow at levels comparable to other yeast without metabolic deficiencies. The resulting colonies also feature one of several different genetic and metabolic profiles, which change in response to the metabolite that is missing. These findings demonstrate that yeast cells can exchange high amounts of metabolites, sufficient to form cooperative colonies, and as metabolite concentrations are not altered compared to normal cells, it is likely that exchange of metabolites is ongoing between neighbours in yeast communities. The additional discovery that yeast stop making metabolites when they can obtain them from neighbouring cells has implications for research. This is because many yeast genetic studies use metabolically deficient strains that are supplemented in culture with metabolites. Future work could address whether such supplementation has kept certain functions of metabolism hidden.
Type of Medium:
Online Resource
ISSN:
2050-084X
DOI:
10.7554/eLife.09943.001
DOI:
10.7554/eLife.09943.002
DOI:
10.7554/eLife.09943.003
DOI:
10.7554/eLife.09943.004
DOI:
10.7554/eLife.09943.005
DOI:
10.7554/eLife.09943.006
DOI:
10.7554/eLife.09943.007
DOI:
10.7554/eLife.09943.008
DOI:
10.7554/eLife.09943.009
DOI:
10.7554/eLife.09943.010
DOI:
10.7554/eLife.09943.011
DOI:
10.7554/eLife.09943.012
DOI:
10.7554/eLife.09943.013
DOI:
10.7554/eLife.09943.014
DOI:
10.7554/eLife.09943.015
DOI:
10.7554/eLife.09943.016
DOI:
10.7554/eLife.09943.017
DOI:
10.7554/eLife.09943.018
DOI:
10.7554/eLife.09943.019
DOI:
10.7554/eLife.09943.020
DOI:
10.7554/eLife.09943.021
DOI:
10.7554/eLife.09943.022
DOI:
10.7554/eLife.09943.023
DOI:
10.7554/eLife.09943.025
DOI:
10.7554/eLife.09943.026
DOI:
10.7554/eLife.09943.024
Language:
English
Publisher:
eLife Sciences Publications, Ltd
Publication Date:
2015
detail.hit.zdb_id:
2687154-3
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