Abstract
1) The suspenion of E. coli was heated under the environment of oxygen with from 1 to 10 absolute atmospheric pressure (aap). At each temperature, the decimal reduction time showed a peak at 1aap, and then decreased as the pressure rose.
2) When E. coli was cultivated under the hyperbaric oxygen, the lag time was delayed with the increase of pressure up to 4aap. At 5aap or more of oxygen, no bacterial growth was observed. Generation time increased linearly with the pressure of oxygen up to 3aap.
3) The pretreatment with hyperbaric oxygen had not effect on the growth rate thereafter.
4) When the culture was oxygenated during the growth phase, the following relationship was observed between the number of the microbes (N) and oxygen pressure (p)
N=N0e(3.7-0.8p)t(t: time in hour)
5) The amount of final growth showed the peak at 1aap. Exceeding 1aap, the amount diminished remarkably with the rise of the pressure.
6) Hyperbaric nitrogen showed no effect on the growth of bacteria.
7) Reducing agents added to the media had no protecting effect against the oxygen action on E. coli.
8) Antimetabolites showed the synergic, antagonistic and indifferent attitude toward the effect of hyperbaric oxygen depending on the mode of action of the chemicals.
