I have precipitated phage as pellets using PEG and NaCl method then i have suspended the pellets using 5ml SM buffer with gelatin, lytic activity of the phage was confirmed using spot test, after storage in falcon tube for 3 days in 4Co, lytic activity was disappeared.
Could anyone tell me what is the wrong?
Is there any cloudiness in the suspension? Perhaps bacteria have grown in it. One might learn by spreading or doing a dilution series spot test on an appropriate media for the bacteria on which the phage stock were grown.
What phage are you working with? What are the details of the protocol you used? What methods did you use to eliminate the bacteria from the phage stock?
Dear professor David,
lytic activity was confirmed in the first time and disappeared in the second time. serial dilution was carried out without result.
there are no signs of contamination .
i am working with phage active against Acinetobacter baumannii.
3Ml of ( PEG 6000 20% + 2.5M NaCl ) was added to 30 ml of phage lysate the filtered through 0.45um filter. the mixture left in ice for one hour followed by centrifugation at 11000*g for 45 min supernant was discarded and the pellets was reconstituted in 5 ml SM buffer and stored in refrigerator.
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