STARVATION-SURVIVAL AND RESUSCITATION OF GFP-MARKED Ah4332 IN THE OVERWINTERING WATER

Starvation survival of GFP marked Ah4332 strain had been detected at 8～10℃ in the overwintering water in laboratory. The changes of bacterial amount were monitored by three counting ways.After 41 days the plate counts)PC)of Ah4332GFP dropped to zero. In all cases,the total number of Ah4332GFP remained the same level with direct viable count(DVC)or direct count(DC),but the DVC was about one or two log lower than the DC.It suggested that the Ah4332GFP had entered a dormant,viable but nonculturable(VBNC)state. The resuscitation of VBNC Ah4332GFP strain was tested in different conditions.Under increasing the temperature,culturable Ah4332GFP strain was recovered from VBNC state by two methods of either adding some substances e.g.fish serum,supernatant from late logarithmic phase Ah4332GFP cultures or injecting VBNC Ah4332GFP into the rabbit ligated ileal loop. By using electron microscopy and vertical fluorescent microscopy,the culturable and VBNC Ah4332GFP were observed.Comparing with the culturable cells of Ah4332GFP ,the VBNC bacteria processed a significant reduction in cell size and a morphological change from bacilli to cocci,meanwhile the cell membrane and cell wall were intact.It demonstrated that the VBNC state of Ah4332GFP was not the L-form bacterium.