High Pressure Tolerance Research Articles

Decrease in high pressure tolerance of resting cells of Escherichia coli K-12 by pretreatment with alternating current.

The effects of 50 Hz alternating current (a.c.) pretreatment on the high pressure tolerance of Escherichia coli K-12 cells were found to be dependent on the composition of the solutions suspending the cells during treatment with pressure up to 4000 kg/cm2 at room temperature for 10min. When pressurized in a 8/15 M NaCl solution (pH 7.0) at 3000 kg/cm2 after a.c. exposure of 600mA/cm2 for 2 hr at 35°C, the exposed cells could not survive as well as those pressurized in a 8/15 M phosphate buifer (pH 7.0): the value of the ratio of the exposed cells surviving to that of the unexposed ones was less than 0.1 in an NaCl solution and about 0.5 in a buffer. The lethal action of high pressure on the cells suspended in M/15 buffer was appreciably counteracted by 8/15 M buffer but not by 8/15 M NaCl solution.

The Effects of Hydrostatic Pressure on Living Aquatic Organisms V. Eurybiotic Environmental Capacity as a Factor in High Pressure Tolerance

AbstractStudy on the total spectrum of organisms (72 species) subjected to hydrostatic pressure as of this date allows one to established categories of pressure tolerance (resistance): Extremely high – eurybiotic forms (1000–1200 atm), High – marine littoral, planktonic, freshwater (600–1000 atm), Moderate – marine littoral, planktonic, freshwater (400–600 atm), Low – planktonic, freshwater (100–300 atm), Extremely low – planktonic, freshwater (0–100 atm). The average pressure tolerance of marine littoral species is higher than that of planktonic species but not significantly different from freshwater species. Eurybiotic species which are not marine seem to show the highest pressure tolerance.