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Dioctyl phthalate increases the percentage of unsaturated fatty acids with a concomitant decrease in cellular heat
Brendan P G Curran1, Seunath A Khalawan1, Mahua T Chatterjee1
1School of Biological Sciences, Queen Mary and Westfield College, Mile End Road, London E1 4NS, UK1.
Microbiology (Reading, England)
|October 6, 2000
Summary
New plastic containers contaminated yeast growth medium with dioctyl phthalate, altering yeast cell lipid profiles and heat shock response (HSR). This compound increased unsaturated fatty acids and decreased HSR sensitivity without affecting growth.
Area of Science:
- Cellular Biology
- Environmental Toxicology
- Biochemistry
Background:
- Yeast cells grown at 37°C typically exhibit higher unsaturated fatty acids and heat shock response (HSR) than those grown at 25°C.
- A recent observation showed a loss of this distinction, with 25°C cells becoming similar to 37°C cells.
Purpose of the Study:
- To investigate the cause of altered yeast cell lipid profiles and HSR.
- To identify the contaminant responsible for these changes in yeast grown in specific media.
Main Methods:
- Yeast cells (DBY747) were grown in standard and reconstituted yeast nitrogen base (YNB) media.
- High-performance liquid chromatography (HPLC) and mass spectroscopy were used to identify the contaminant.
- Cells were treated with varying concentrations of the identified compound to assess its effects.
Main Results:
- Reconstituted YNB medium from new plastic containers induced higher unsaturated fatty acid levels and reduced HSR sensitivity in 25°C-grown yeast.
- Dioctyl phthalate was identified as the active contaminant, effective even at a 1:600 dilution.
- Pure dioctyl phthalate (36 microM) mimicked these effects without impacting cell growth rate up to 144 microM.
Conclusions:
- Dioctyl phthalate contaminates yeast growth media, leading to increased unsaturated fatty acids and decreased HSR sensitivity.
- The heat shock response (HSR) in yeast is highly sensitive to cellular unsaturated fatty acid levels.
- Dioctyl phthalate alters yeast cell physiology without compromising growth, highlighting potential environmental impacts on cellular stress responses.