Application Of FISH-FCM In Detection Of Host Lysing Velocity By BALOs

Bdellovibrio sp. is a kind of parasitic microorganism which can act as phage and demonstrate desirable ability in eliminating pathogenic bacterium that can lead to aquaculture disease. This study determinated two bacterial strains which were isolated from fresh water of South Lake,and had abilities to lyse the host Aeromonas hydrophila as Bdellovibrio bactervorus through phage-plaques charicterization, electronic microscopy and 16s rDNA sequence analysis.One of the two BDs, CHA1 had an ability to lyse a undetermined Gram negative bacterial host SD6. FISH(Fluorescence in situ Hybridization) was conducted to obtain optimal hybridyzation conditions by a universal probe as well as a specific probe, targeting at host bacterial SD6 and bdellovibrio. Sp, respectively. The optimal conditions for the host is: permeabilizing by 0.2% TritonX-100 for 15min, hybriding at 48℃for 2h with probe concentration 2ng/ul and for CHA1: permeabilizing by 0.2% Triton X-100 for 15min, hybriding at 48℃for 3h with probe concentration 1ng/ul。A bi-probe test on host-bdellovibrio system proved making a good dictinction on them when oberved by flurorescence scopy.Samples with different concentrition of host and bdellovibrio were analysed both by FCM and spread plates. Results for the host showed good coincidence between two method while that for bdellovibrio was significantly differenct. A t-test validated FISH-FCM method is appliable to host lysation veluloty study. This method greatly facilliated host and bdellovibrio detection with shorter period of less than 1 day and easier operation as well as a good accuration of 103cfu/ml, all the advantages promise good applying prospect for this method.