Bacillus strain displays better protective effects in Vibrio-challenged gnotobiotic Artemia]]>

摘要

In this study, theBacillussp. JL47, a superior PHB-accumulatingBacillusstrain identified from the previous work, was tested for its protective effects in gnotobioticArtemia franciscanaduring a pathogenicVibrio campbelliichallenge. The utilization of gnotobioticArtemiais important in this experiment because any possible microbial interference (which are naturally present in conventional culture system) are eliminated in this model culture system, hence the interpretation of the results in this mechanistic study can be more conclusive. The survival of theArtemiafed theBacillussp. JL47 at 1×107cellsmL?1was significantly higher as compared with the challenged control and the survival was almost doubled when the dose was increased to 5×107cellsmL?1. However, feeding theArtemiaat 106cellsmL?1or lower showed no significant protective effects. Based on these densities, the estimated concentration of amorphous PHB showing a significant protection inArtemiawasc.2.44mgL?1and the effects were even better when the amorphous PHB level was increased to 12.19mgL?1. Furthermore, feedingBacillussp. JL47 containing 55% amorphous PHB (on CDW) toArtemiashowed a significantly higher survival in aVibriochallenge relative toBacilluscontaining 29% PHB. The data suggest that the amorphous PHB accumulated in theBacillussp. JL47 strain is an important determinant for the increased survival of challengedArtemia.