phage titer problem - (Sep/23/2008 )
i am having problems reproducing a phage titer using the agar overlay method. I am working with Bacillus subtilis and a lysogenic phage SPO2 (mitomycin C is used as the inducing agent). Initial attempts to titer the phage were successful but subsequent attempts have not been. Instead of individual plaques, i only see clearings of no growth. I have tried to increase the dilution up to 10^13 but still, no plaques. I've also tried with new Bacillus subtilis cells. I am at a loss of what to do next. Any advice would be greatly appreciated!!!
One possibility: 100% of your B. subtilis has already harboring a lysogenic phage in its genome. Try induction without SPO2.