Abstract
The preparations described below were made from 12 to 18 hour cultures of gonococci grown on an agar medium 1 containing a tryptie digest of egg-white from which the heat-coagulable proteins had been removed. The organisms were taken up in saline, centrifuged, washed and again centrifuged until well packed. They were then extracted by suspending each cubic centimeter of packed, moist organisms in 200 cc. of N/100 NaOH and allowing the suspension to stand over night in the refrigerator. After removal of the bacterial debris by centrifugation the clear supernatant liquid was acidified with acetic acid to maximum precipitation.
The precipitate comprising the so-called bacterial “nucleoprotein” was separated from the supernatant liquid (the subsequent treatment of which is described below) by centrifugation, redissolved in N/100 NaOH, and reprecipitated with dilute acetic acid. After 4 to 6 repetitions of this procedure, the final solution of the “nucleoprotein” in N/100 NaOH was dialysed against distilled water and the neutral suspension evaporated to dryness at 40°-6o°C. in an air current. In the dry state it has been kept at room temperature for several months without evidence of deterioration. The usual reactions of proteins were all positive: biuret, Millon, Xanthoproteic, Hopkins-Cole, sulpho-salicylic and phosphotungstic acid.
The non-protein fraction was obtained from the supernatant fluid of the first acetic acid precipitation. This liquid was evaporated to small bulk (about 10 cc.) heated in a boiling water bath for 15 minutes, filtered from coagulated protein and then treated with about 10 volumes of 95% ethyl alcohol. After standing long enough to insure complete denaturation of any denaturable proteins the precipitate was removed by centrifugation, dissolved in water, filtered, reduced to small bulk by evaporation and again treated with alcohol.
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