Recycle for longer life

19 March 2012

Aberystwyth scientists, in collaboration with colleagues at Manchester and Cambridge, have shown that yeast cells recycle to stay alive when food is in short supply.

Dr Hazel Davey said “Microbiologists typically cosset their microbes in the laboratory, providing them with everything they need for growth but in the natural environment there are stressful conditions and this is where things are much more interesting – and far more relevant when it comes to involving microbial processes in models of climate change.” Improving our understanding of what mechanisms yeast cells use to stay alive also has relevance to research on the impact of diet on ageing in humans.

The work involved competing 6,000 strains of yeast each lacking a different gene and then using cell sorting and array analysis techniques to separate and identify those that were least able to survive for 9 days without the addition of nutrients. Deletion of genes involved in recycling proteins, fatty acids and ribosomes led to reduced survival showing that when times are hard yeast cells recycle their own cellular components to stay alive.

Although the Saccharomyces cerevisiae (Baker’s yeast) genome sequence was published in 1996 there are still ~25% of the identified open reading frames that do not have a verified function. Dr Hazel Davey commented “Over 100 of these genes of unknown function were identified in our screening experiments where they appear to have an impact on cell survival. It is possible that their function is only apparent when cells do not have ideal growth conditions and standard laboratory studies would not identify these.”

The work also revealed that in the microbiological world at least, being first out of the starting blocks in a race is very important – those cells that were able to start growth quickly when nutrients became available were able to outcompete cells that could grow more quickly but took longer to get started. The use of Saccharomyces cervisiae as a model organism means that these findings have relevance to understanding the impact of nutrient limitation such as calorie restriction on ageing and longevity in humans as many cellular pathways and functions are conserved.

The research has been accepted for publication in Environmental Microbiology and is available as an "Early View" publication.

Genome-wide analysis of longevity in nutrient-deprived Saccharomyces cerevisiae reveals importance of recycling in maintaining cell viability
Hazel M. Davey, Emma J. M. Cross, Christopher, L. Davey, Konstantinos Gkargkas, Daniela Delneri, David C. Hoyle, Stephen G. Oliver, Douglas B. Kell and Gareth W. Griffith

Article first published online: 22 FEB 2012 | DOI: 10.1111/j.1462-2920.2012.02705.x