STUDY ON SCREENING OF A QUORUM SENSING QUENCHING BACILLUS SP. STRAIN AND ITS ANTIBACTERIAL EFFECT ON ZEBRAFISH
The purpose of the experiment was to prevent and control bacterial infections by selecting Bacillus spp. based on the quorum sensing system. 33 strains of Bacillus spp. were selected from the sediment of fresh water culture pond. Chromabacterium biolaceum was used as the report stain, strain T-1 without hemolysis property to inhibit quorum sensing significantly was selected with "H" streaking and double layer agar plates methods, which was finally identified as Bacillus licheniformis based on the 16S rDNA sequences. The protection effect of B. licheniformis T-1 on zebra fish showed that the survival of zebra fish reached 70% when challenged with 5.8×107cfu/mL of Aeromonas hydrophlia in 96 h. we also analysis the protective effect of B. licheniformis on early infection of A.hydrophlia The results indicated that there would be better protective effect when the zebrafish injected B. licheniformis at the 0, 4 hour after infection, the survival of zebrafish were more than 60%. For further analysis of the inhibitory mechanism of the B. licheniformis T-1, we measured the draft genome profile of B. licheniformis T-1 and one of the metalloprotease Ytnp gene to degrade AHLs signal molecular was amplification. In a conclusion, B. licheniformis T-1 to inhibit quorum sensing could be used as the potential antibacterial agents to protect the host from the bacterial infection.