Abstract
During a study of the bacteriolytic enzyme, lysozyme, 1 we wished to compare its properties with those of bacteriophage. The method used for the purification of lysozyme was not applicable to bacteriophage because of the extreme sensitivity of phage to the common organic solvents.
Previous efforts at purification of bacteriophage have usually employed physico-chemical methods: ultrafiltration through membranes of graded porosity, 2 adsorption, 3 and more lately centrifugation. 4 In the present work the removal of undesired culture medium and bacterial components was attempted by chemical methods and the behavior of phage toward some chemical agents was observed.
The phage and coli strains here used were obtained from Dr. M. Holden, of the Department of Bacteriology. The organism gives the sugar reactions of Escherichia coli Communis. The phage was isolated from a normal stool several years ago and has been propagated since on the coli strain.
In obtaining phage for concentration an 18-hour culture was inoculated into a liter of beef heart infusion broth (pH 7.4-7.6) and incubated at 37° until clouding was plainly visible. A small amount of the phage broth was added and the flask was incubated another 18 hours. Complete clearing usually occurred and the broth was filtered through a Berkefeld N filter.
In titrating the various phage preparations 0.5 cc. of progressive dilutions were placed in sterile Wassermann tubes and 4.5 cc. portions of a 3 to 4-hour culture of the organism were added. A control tube of 0.5 cc. of sterile broth with the culture was used with each series. After 18 hours at 37° readings were made, the highest dilution giving complete clearing being designated as the end point.
Get full access to this article
View all access options for this article.