Document Detail

Weak acid preservatives block the heat shock response and heat-shock-element-directed lacZ expression of low pH Saccharomyces cerevisiae cultures, an inhibitory action partially relieved by respiratory deficiency.
MedLine Citation:
PMID:  8025674     Owner:  NLM     Status:  MEDLINE    
Inhibition of microbial growth by weak acid preservatives increases with medium acidification, since these agents enter cells in the undissociated state. Many of the effects of these acids are due to the cytoplasmic acidification they cause as they dissociate in the higher pH environment of the cytosol. Sorbic and benzoic acids, two widely used preservatives, were found to exert pronounced effects on the heat shock response and thermotolerance of Saccharomyces cerevisiae. These effects were strongly influenced by the pH of the culture medium. In low pH cultures sorbate inhibited the induction of thermotolerance by sublethal heat shock, causing strong induction of respiratory-deficient petites among the survivors of heat treatment. However, when the culture pH was above 5.5 sorbate acted as a powerful chemical inducer of thermotolerance in the absence of any sublethal heat treatment. Sorbate and benzoate also inhibited heat induction of the major heat shock proteins in low pH yeast cultures. This appears to result from lack of induction of the heat shock element (HSE) promoter sequence since sorbate prevented heat induction of a HSE-lacZ fusion at low pH. The uncoupler carbonyl cyanide m-chlorophenylhydrazone (CCCP) and the plasma-membrane-ATPase inhibitor diethylstilboestrol were identified as additional inhibitors of heat induction of heat shock proteins. Numerous chemicals induce the heat shock response in the absence of heat stress, but sorbate, benzoate, CCCP and diethylstilboestrol are the first compounds shown to act as selective inhibitors of heat-induced protein expression in yeast. In the presence of sorbate concentrations which, at low pH, totally inhibit both the heat shock response and growth of cells competent in respiration, respiratory-deficient petites still retain a limited capacity for growth and for heat induction of heat shock proteins. This restoration of a response to heat shock in acidified sorbate-treated cultures of petites might contribute to their higher capacity for growth in the presence of sorbate.
L Cheng; P W Piper
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Microbiology (Reading, England)     Volume:  140 ( Pt 5)     ISSN:  1350-0872     ISO Abbreviation:  Microbiology (Reading, Engl.)     Publication Date:  1994 May 
Date Detail:
Created Date:  1994-08-10     Completed Date:  1994-08-10     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  9430468     Medline TA:  Microbiology     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  1085-96     Citation Subset:  IM    
Department of Biochemistry and Molecular Biology, University College London, UK.
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MeSH Terms
Adaptation, Physiological
Benzoates / pharmacology*
Benzoic Acid
Food Microbiology
Food Preservatives / pharmacology*
Gene Expression Regulation, Fungal
Heat-Shock Proteins / biosynthesis*,  genetics
Hot Temperature
Hydrogen-Ion Concentration
Lac Operon
Oxygen Consumption / genetics
Recombinant Fusion Proteins
Saccharomyces cerevisiae / drug effects,  physiology*
Sorbic Acid / pharmacology*
Uncoupling Agents / pharmacology
Reg. No./Substance:
0/Benzoates; 0/Food Preservatives; 0/Heat-Shock Proteins; 0/Recombinant Fusion Proteins; 0/Uncoupling Agents; 110-44-1/Sorbic Acid; 65-85-0/Benzoic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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