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High pressure represses expression of the malB operon in Escherichia coli
T Sato1, Y Nakamura, K K Nakashima
1DEEPSTAR group, Japan Marine Science and Technology Center, Yokosuka, Japan.
Abstract:
The formation of plaques by lambda phage in Escherichia coli was prevented by elevated hydrostatic pressure; phage plaques were not detected at 30 MPa. Furthermore, using promoter fragments derived from the malB operon, we showed that gene expression initiated from both promoters (malK-lamB and malEFG) was repressed by elevated hydrostatic pressure. Our findings suggest that high pressure affects gene expression directed by the malB regulatory interval, and this may cause a decrease in the quantities of lambda receptor protein, LamB.
Insights
Elevated hydrostatic pressure prevents lambda phage plaque formation in Escherichia coli. High pressure represses gene expression from the malB operon, potentially reducing lambda receptor protein (LamB) levels.
Area of Science:
- Microbiology
- Molecular Biology
- Biophysics
Background:
- Bacteriophages like lambda phage are crucial tools in molecular biology and have implications in bacterial infection.
- Bacterial gene expression is regulated by various environmental factors, including physical forces.
- The malB operon in Escherichia coli encodes proteins involved in nutrient transport and is regulated by specific promoters.
Purpose of the Study:
- To investigate the effect of elevated hydrostatic pressure on lambda phage plaque formation in Escherichia coli.
- To determine if high pressure influences gene expression from the malB operon.
- To explore the potential link between pressure-induced changes in gene expression and lambda receptor protein (LamB) levels.
Main Methods:
- Utilizing plaque assays to observe lambda phage propagation under varying hydrostatic pressures.
- Employing promoter-reporter assays with promoter fragments from the malB operon (malK-lamB and malEFG) to quantify gene expression.
- Analyzing the impact of hydrostatic pressure (up to 30 MPa) on phage viability and gene transcription.
Main Results:
- Elevated hydrostatic pressure significantly inhibited lambda phage plaque formation, with no plaques detected at 30 MPa.
- Gene expression initiated from both malK-lamB and malEFG promoters was repressed under elevated hydrostatic pressure.
- These findings indicate that high pressure directly affects the regulatory mechanisms of the malB operon.
Conclusions:
- High hydrostatic pressure acts as an inhibitor of lambda phage proliferation in Escherichia coli.
- Pressure-induced repression of the malB operon suggests a mechanism involving reduced lambda receptor protein (LamB) synthesis.
- This study highlights the influence of physical forces on microbial gene regulation and phage-host interactions.