The effects of hydrostatic pressure on ribosome conformation in Escherichia coli: an in vivo study using differential scanning calorimetry

• Published in: Microbiology (Society for General Microbiology) 1999-02, Vol.145 (2), p.419-425
• Main Authors: Niven, Gordon W, Miles, Christopher A, Mackey, Bernard M
• Format: Article
• Language: English
• Subjects: Action of physical and chemical agents on bacteria; Bacterial Proteins - chemistry; Bacteriology; Biological and medical sciences; Calorimetry, Differential Scanning; Culture Media; Escherichia coli; Escherichia coli - growth & development; Escherichia coli - physiology; Fundamental and applied biological sciences. Psychology; Hot Temperature; Hydrostatic Pressure; Microbiology; Protein Conformation; Ribosomal Proteins - chemistry; Ribosomes - chemistry; Ribosomes - physiology
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/13500872-145-2-419

Institute of Food Research, Reading Laboratory, Earley Gate, Whiteknights Road, Reading RG6 6BZ, UK University of Bristol School of Clinical Veterinary Science, Churchill Building, Langford, Bristol BS40 5DU, UK Author for correspondence: Gordon Niven. Tel: [phone]. Fax: [phone]. e-mail: [e-mail] ABSTRACT Summary: Differential scanning calorimetry of whole Escherichia coli cells allowed the detection in vivo of changes in ribosome conformation. This enabled for the first time an analysis of the effects of high hydrostatic pressures on ribosomes in living cells. A correlation was observed between loss of cell viability and decrease in ribosome-associated enthalpy in cells subjected to pressures of 50-250 MPa for 20 min. Cell death and ribosome damage were therefore closely related phenomena. In pressure-treated cells, the thermogram peak temperatures decreased, suggesting that the remaining ribosomes had adopted a less stable conformation. During subsequent incubation of the cultures at 37°C, peak temperatures and enthalpies gradually increased over a period of 5 h. This change in ribosome conformation had no apparent effect on cell survival, as viability continued to decrease. The addition of 5 mM MgCl 2 before pressure treatment of cells prevented the reduction in stability of surviving ribosomes but had no effect on the initial loss of enthalpy or on cell viability. Keywords: ribosome, differential scanning calorimetry, hydrostatic pressure, barophysiology