The sensitivity of the yeast, Saccharomyces cerevisiae, to acetic acid is influenced by DOM34 and RPL36A.

Jennifer Yixin Jin ,Tom Kazmirchuk,Daniel Burnside,Katayoun Omidi,Rami Megarbane,Martin Holčı́k ,Anna York-Lyon,Sarah Shaikho,Myron L. Smith,Imelda Gálvan Márquez ,M. A. Hooshyar ,Thet Naing,Houman Moteshareie,Cindy W. Leung ,Kristina Shostak,Paula Ludovico,Bahram Samanfar,Mohan Babu,Maryam Hajikarimlou,Ashkan Golshani,Kama E. Szereszewski

doi:10.7717/peerj.4037

Abstract

The presence of acetic acid during industrial alcohol fermentation reduces the yield of fermentation by imposing additional stress on the yeast cells. The biology of cellular responses to stress has been a subject of vigorous investigations. Although much has been learned, details of some of these responses remain poorly understood. Members of heat shock chaperone HSP proteins have been linked to acetic acid and heat shock stress responses in yeast. Both acetic acid and heat shock have been identified to trigger different cellular responses including reduction of global protein synthesis and induction of programmed cell death. Yeast HSC82 and HSP82 code for two important heat shock proteins that together account for 1–2% of total cellular proteins. Both proteins have been linked to responses to acetic acid and heat shock. In contrast to the overall rate of protein synthesis which is reduced, the expression of HSC82 and HSP82 is induced in response to acetic acid stress. In the current study we identified two yeast genes DOM34 and RPL36A that are linked to acetic acid and heat shock sensitivity. We investigated the influence of these genes on the expression of HSP proteins. Our observations suggest that Dom34 and RPL36A influence translation in a CAP-independent manner.

Highlights

Bacterial contamination is one of the major hurdles behind reduced yield of industrial alcohol fermentation by yeast (Skinner & Leathers, 2004)
HSC82 and HSP82 are required for the activation of a number of key cellular regulatory proteins like transcription factors and kinases including Hap1 zinc finger transcription factor involved in regulation of gene expression in response to levels of heme and oxygen and Swe1 protein kinase that regulates G2/M transition (Burnie et al, 2006)
To further investigate the involvement of DOM34 and RPL36A in regulation of translation, we studied the genetic interactions they made with genes that influence the protein synthesis pathway in yeast

Summary

Introduction

Bacterial contamination is one of the major hurdles behind reduced yield of industrial alcohol fermentation by yeast (Skinner & Leathers, 2004). These infections often compete with ethanol producing yeast for sugars and other nutrients. Certain antibiotics such as virginiamycin are shown to effectively reduce bacterial contamination during alcohol fermentation process (Hynes et al, 1997). The presence of acetic acid, can put a stress on the biology of yeast cells reducing yeast’s fermentation abilities. It has been shown that acetic acid can penetrate into the yeast cells, which leads to intracellular acidification, anion accumulation and inhibition of cellular metabolic pathways (Casal, Cardoso & Leão, 1996)

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Results

Conclusion