蟹源拟态弧菌最佳产毒条件的筛选

Selection of optimal producing condition of the exotoxin of Vibrio mimicus from Eriocheir sinensis

通过体外试验,探讨了培养条件的改变对蟹源拟态弧菌(HX-4)产毒量的影响。结果表明,培养基种类、氯化钠浓度、初始pH、溶解氧、培养温度和时间的不同均可影响细菌产毒量,HX-4菌株的最佳产毒条件为细菌接种于起始pH为8.0,含0.5%NaCl-BHI培养基,28℃振荡培养36h或静置培养48h。同时,通过动物实验测定了外毒素的致病性,结果显示,外毒素粗提液对小鼠及河蟹均有致病性。粗提液的溶血活性越高,对动物的致死率也越高。具有蛋白酶活性而无溶血素活性的粗提液,对动物只有致病性,而无致死性。

Regulations of cultural conditions on the exotoxin expression of Vibrio mimicus HX-4 from Eriocheir sinensis have been studied in vitro. Through measuring hemolytic and proteolytic activities of crude exotoxin in different cultural conditions.The results demonstrated that different media,NaCl percent,initial pH, soluble oxygen, cultural temperature and time all effected on the exotoxin production. The optimal conditions of the exotoxin expression are that the HX-4 strain is inoculated in 0.5% NaCl-BHI with initial pH 8.0 at 28℃ for 36h in shaking cultivation or 48h in stationary cultivation.The pathogenic experiments of the crude exotoxin to mice and Eriocheir sinensis also have been finished.The results showed that the crude exotoxin is pathogenic to both of experimental animals, the higher the hemolytic titer of crude exotoxin is,the higher its lethal rate to experimental animals is. The crude solution of exotoxin with protease and no hemolysin has pathogenicity, but no lethality to experimental animals.