SUMMARY: The effect of hydrogen peroxide on the growth of lt2 in a mineral glucose medium was investigated. The HO produced a lag period, the duration of which increased as the concentration of HO in the medium was increased from 1 to 60 μg./ml. Growth subsequent to the lag period proceeded at the normal growth rate at concentrations of HO as high as 30 μg./ml. Storage of HO in the sterile growth medium resulted in a disappearance of HO with a half-life of about 48 hr. The disappearance of HO because of reaction with glucose resulted in proportionate decreases in the growth inhibitory action of the medium. destroyed HO rapidly (half-time = 60 min.)—an effect attributed largely to bacterial catalase. The catalatic activity of the bacteria was decreased or eliminated by boiling or by treatment with cyanide. The growth of the bacteria in HO resulted in the development of HO resistance. By subculturing the wild type lt2 in medium containing successively higher HO concentration, a resistant strain designated lt2 p was isolated which grew in the presence of HO concentrations that were completely inhibitory to the wild type.

The experimental results support the generally accepted conclusion that bacterial catalase acts in protecting the organism from HO. It is pointed out that in biological media HO readily forms adducts with many compounds, including carbonyls, amino acids and thymine. Consequently, the inhibitory effects of HO, especially in studies involving auxotrophs, may be partly or wholly due to the peroxide adduct rather than ‘free’ HO.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error