一株芽孢杆菌用作水霉病防治的研究

The potential of a Bacillus strain as the biological source of pharmaceutical compound against Saprolegniasis

水霉病(Saprolegniasis)是包括草鱼等四大家鱼在内的淡水鱼最常见的真菌病,以往较为有效的防治药物为孔雀石绿,孔雀石绿禁用后渔业生产上对该病的防治遇到了极大的困难。本文分离到一株芽孢杆菌Sh1,经16S rDNA序列测定确定为解淀粉芽孢杆菌。水霉菌拮抗实验表明,Sh1菌落周围产生直径约12 mm的抑菌圈。动物安全性实验表明,腹腔注射108CFU/mL的Sh1对草鱼的生长没有任何不良影响。显微观察表明,Sh1能明显抑制水霉菌的菌丝生长。对Sh1发酵液中活性成分的理化性质进行分析,发现蛋白酶K消化、加热处理、有机溶剂抽提等都不影响其对水霉菌的抑制作用,从而推断该物质为非蛋白的耐热的可溶性化合物。这些数据表明Sh1有希望用作提取替代孔雀石绿的水霉病药物的生物药源。

Saprolegniasis is the most common fungus disease among the fresh water fish in China,including the four major carps such as Grass carp.Malachite Green was once regarded as the most effective medicine for Saprolegniasis;as a carcinogen,it was now completely forbidden all around the world.Saprolegniasis pose as a great difficulty for the fishery culture industry since no cost-effective drugs are available.A novel Bacillus strain Sh1 was identified as Bacillus amyloliquefaciens through 16S rDNA sequence analysis and morphological characters.Antagonistic assays indicated that Sh1 could form a standard inhibition zone when co-cultured with Saprolegnia.Animal bio-safety test showed that Sh1 was safe to Grass carp compared with pathogenic bacterial control.Microscopic observation discovered that Sh1 inhibited the mycelia growth of Saprolegnia.Furthermore,the active compound contained in the fermentation liquid of Sh1 was found highly resistant to heat treatment,proteinase K treatment,and extraction with organic solvent.These data suggested that Sh1 functioned through a non-protein substance and might be a good biological pharmaceutical compound resource against Saprolegniasis for the fishery medicine industry.