Correlation between Extracellular Enzymes and Virulence of Aeromonas hydrophila

嗜水性需氮單胞菌菌體外酵素與其致病力的相互關係

邱素芬(Shu-Fen Chiou) ； 張敏政(Ming-Chung Chang)

《臺灣水產學會刊》 21卷4期 (1994/12) Pp. 369-379

https://doi.org/10.29822/JFST.199412.0008

摘要

嗜水性需氣單胞菌是一俟機性病原菌，會引起魚類的出血性敗血症。本實驗觀察該菌菌體外酵素對魚細胞的影響，進而探討這些酵素在魚類致病過程中所扮演的角色。將帶有deoxyribonuclease (DNase) or lipase or protease基因的質體轉殖到大腸菌，培養12小時後取其上澄液，一方面進行酵素活性分析，另一方面進行酵素對虱目魚細胞株及老鼠纖維母細胞株之影響。魚細胞注入嗜水性需氣單胞菌的細胞外萃取物後經過了6小時，發現細胞有死亡浮起的現象。加入DNase or lipase後經過了16小時，發現細胞沒有什麼改變，而加入protease後經過了16小時，發現細胞的外型有些改變且有小斑點產生。當protease加入老鼠纖維母細胞株後亦發現細胞外型改變。因此推測DNase or lipase與致病力沒有什麼關係，而protease與致病力較有關係，但此protease不是唯一的致病因子，可能須有其他因子互相作用。

關鍵字

致病力 ； 菌體外酵素 ； 嗜水性需氮單胞菌

並列摘要

Aeromonas hydrophila is an opportunistic pathogen which causes the hemorrhagic sep-ticemia of fish. This study examined the influence of extracellular enzymes of the bacteria in fish and mouse cells in vitro. The plasmid containing dcoxyribonuclcasc (DNase) geneor lipase gene or protease gene from A. hydrophila was transformed into Escherichia coli. After these E. coli were cultured for 12 hours, the supernatant was analysed for enzymeactivity and was examined for its cytotoxic effect on cell lines of milkfish Chanos chanosand mouse fibroblast. The results showed that fish cells died after exposed to the culture supernatant of A. hydrophila for 6 hr. However, cells treated with the culture supernatant of E. coil containing DNase or lipase gene showed little change, while cells treated with the culture supernatant of E. coil containing protcase gene showed some morphological change with the appearance of small spots. The similar effect was also observed on mouse fibroblast cells treated with cloned protease. Therefore, it is suggested that DNase or lipase has little contribution on the virulence of the bacteria, while protease does. Nevertheless, protease is not the sole virulence factor. It has to interact with other factors to be effective.

並列關鍵字

Virulence ； Extracellular enzyme ； Acromonas hydrophila