Abstract
Among the currently recognized pathogenic vibrios, V. vulnificus and V. cholerae non O1 are the most serious bacteria from the point of view of sea food hygiene in Korea. In this paper, the authors compared the hemolytic activities of the crude hemolysin produced by V. vulnificus and V. cholerae non O1 isolated from shellfish collected in Chungmoo, Korea. The authors also attempted to improve the purification method of V. vulnificus hemolysin(VVH) and tried to make antiserum with the purified hemolysin. VVH was produced in abundance in heart infusion broth containing $2\%$ NaCl in a shaking cultivation process(140rpm) at $37^{\circ}C$ for 15 hours. While hemolysin production patterns of V. cholerae non O1 were quite different by the strain during the culture times compared with the V. vulnificus. Hemolytic activity of the VVH on sheep erythrocytes was stronger than those of rabbit, but hemolytic activities of the hemolysin produced by V. cholerae non O1 on rabbit erythrocytes were as much as twice as strong as on those of sheep and horse. VVH was purified by two steps of hydrophobic column chromatography on Phenyl-Sepharose HP with Fast Protein Liquid Chromatography(FPLC). Purification fold and yield of VVH was much improved by changing the elution buffer's pH from 6.0 to 9.8 and adding $1\%$ CHAPS(a zwitter ionic detergent) and $50\%$ ethylene glycol to the 10mM glycine buffer during the repeated hydrophobic column chromatography. Homogeneity of the purified hemolysin was shown by polyacrylamide gel electrophoresis. According to the five times repeated purification results, the specific activity was increased 27500 times and the yield was improved by $23.4\%$ on average. About $250{\mu}g$ of purified hemolysin was harvested from the 2400ml of culture supernatant of V. vulnificus. Molecular weight of VVH was estimated to be 50KDa by the SDS-PAGE and the neutralization scores of the obtained antiserum acting against VVH were $2000{\sim}8500$.
우리나라 남해연안 어패류에서 V. vulnificus, V. cholerae non O1 균을 분리하여 이들 균이 생산한 용혈독소의 활성을 검토하고 특히 치사율이 높은 패혈증 원인균인 V. vulnificus균이 생산한 균체외 단백독소인 hemolysin을 분리정제하고 얻어진 독소를 이용하여 항혈청을 만들었다. 1. V. vulnificus hemolysin(VVH)은 HI broth에서 $37^{\circ}C,\;15{\sim}24hr$ 진탕배양으로 잘 생산되었으며 V. cholerae non O1 균의 경우는 배양 15시간까지는 hemolysin 생산이 증가되었으나 15시간 경과 후에는 균종에 따라 증가되는 것도 있었고 경과 시간에 따라 오히려 감소하는 균주도 있었다. 2. V. vulnificus가 생산한 hemolysin은 면양적혈구에 대한 용혈활성이 강하고 토끼적혈구에 대하여는 약하였으나 V. cholerae non O1 균주는 토끼적혈구에 대한 용혈활성이 면양이나 말 적혈구에 대한 활성보다 2배정도 강하였다. 3. VVH는 hydrophobic Phenyl-Sepharose HP column을 이용하여 washing buffer와 elution buffer의 성분과 pH를 조정하면서 $1\%$ CHAPS를 이용하여 2차에 걸쳐 column chromatography한 결과 정제도와 수율이 매우 좋아졌다. 본 방법으로 다섯 차례에 걸쳐 정제한 결과 정제된 VVH의 specific activity는 $16900{\sim}52300$배로 평균 27,000배 이상 증가하였으며 수율도 $18.2{\sim}33.0\%$로 평균 $23.4\%$나 되었다. 실제로, V. vulnificus 배양액 2400ml로 부터 정제된 hemolysin을 $250{\mu}g$정도 만들 수 있어서 패혈증 비브리오균 연구에 크게 이바지 할수 있을 것으로 사료된다. 4. 정제된 VVH를 SDS-PAGE한 결과 분자량은 50KDa이었으며 토끼를 이용해서 만든 항혈청의 항체가는 $2000{\sim}8500$이었다.