Abstract
In order to obtain a potent RDE preparation, biological studies on the 4Z strain of V. cholerae, on production media and chemical studies on the purification procedure have been conducted. The conclusions will be summarized as follows:
1) Original strain of 4Z was plated out on nutrient agar and colony selections have been repeated. Characteristic S form colony which has been seleted out produced more potent RDE than RS or R type. Moreover, constant titer of RDE was always obtainable with the selected strain.
2) In order to find out the best production medium, 1% nutrient agar, 1% peptone water, meat extract peptone broth and meat infusion broth were examined. The former two was more favourable and among them peptone water was more convenient for further purification.
3) Different kind of peptone was tested for the production of RDE in peptone water, and with Neo-peptone and Teruuchi-peptone, highest titer was obtained.
4) The addition of hog stomach mucin to the peptone water increased the production of RDE as much as 20 times when compared to the plain peptone water. Optimum concentration of mucin was 15-25mg/ml and in this medium maximum titer was obtainable after 16-18 hours incubation.
5) Instead of mucin, egg-white was also available for the stimulation of production.
6) Purification procedure from culture filtrate was examined. Adsorption to and elution from chicken red cells was most important step for purification.
