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AppppA, heat-shock stress, and cell oxidation.
Summary
Salmonella typhimurium LT2 and E. coli accumulate specific adenylylated nucleotides, like diadenosine tetraphosphate (AppppA), during heat shock. These molecules may act as alarmones, signaling cellular stress responses.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Salmonella typhimurium LT2 and Escherichia coli synthesize heat-shock proteins in response to thermal stress.
- Heat shock triggers the synthesis of specific proteins, analogous to those observed in E. coli.
Purpose of the Study:
- To investigate the accumulation of adenylylated nucleotides in S. typhimurium and E. coli under heat shock conditions.
- To explore the potential role of adenylylated nucleotides as alarmones in cellular stress responses.
Main Methods:
- Utilized a two-dimensional thin-layer chromatography system to resolve adenylylated nucleotides.
- Analyzed nucleotide profiles of S. typhimurium and E. coli following heat shock and ethanol exposure.
Main Results:
- Heat shock induced the accumulation of P1,P4-diadenosine-5 -tetraphosphate (AppppA), P1-(adenosine-5 )-P3-(guanosine-3 -diphosphate-5 )-triphosphate (ApppGpp), P1-(adenosine-5 )-P4-(guanosine-5 )-tetraphosphate (AppppG), P1-(adenosine-5 )-P3-(guanosine-5 )-triphosphate (ApppG), and P1,P3-diadenosine-5 -triphosphate (ApppA) in both bacterial species.
- The same adenylylated nucleotides accumulated upon exposure to ethanol, a known inducer of the heat-shock response.
- Previously, these nucleotides were shown to accumulate under oxidative stress conditions.
Conclusions:
- Adenylylated nucleotides, including AppppA, ApppGpp, AppppG, ApppG, and ApppA, accumulate in response to heat shock and ethanol exposure in S. typhimurium and E. coli.
- The common accumulation of these dinucleotides under heat shock, ethanol exposure, and oxidative stress suggests a shared physiological effect.
- Hypothesize that these adenylylated nucleotides function as alarmones, signaling the onset of stress and triggering the heat-shock response.
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