昆虫病原线虫共生细菌抑菌物质的分离与活性研究

Purification and Partial Characterization of An Antibacterial Complex Produced By the Entomopathogenic Bacterium Photorhabdus uminescens

发光杆菌(Photorhabdusluminescens)是从昆虫病原线虫异小杆线虫(Heterorhabditisbacteriophora)体内分离出的能拮抗芽孢杆菌(Bacillussubtilis)的共生细菌,该细菌是寄生在昆虫病原线虫肠道内的一种细菌,二者互惠共生。共生细菌发酵滤液具较强的抑菌活性,48h发酵滤液抑菌圈半径最大达6.5mm;培养滤液经80%硫酸铵沉淀,透析,冷冻干燥后,其粗提物具抗菌活性,但不耐高温,40℃失活,粗蛋白经分子筛SephadexG-100层折柱洗脱,洗脱峰V具抑菌活性。

Phtotolhabdus lunlinescens was a gram-negative enteric bacterium. that was found in association with entomopathogenic nematodes of Heterorhabditis bacteriophora. It can secrete large a mount of antibactelial complex and had a strong inhibiting activity against Bacillus subtilis. At 48h, the longest radius of inhition zone was 6.5 mm. The antibacterial activity and the characterization of the complex were observed. Total complex were precipitated with ammonium sulfate 80% saturation from cell-free culture. The crude extract can't tolerate high temperature. At 40℃, antibacterial activity was lost. The crude extract were purified through a series steps including dialysis and gel filtration chromatography with Sephadex G-100 column. The peak V was active against Bacillus subtilis.