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Dorman:P22 transduction: Difference between revisions
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(New page: P22 is a generalized transducing phage used for constructing Salmonella strains. The P22 derivative used in our lab has a HT (high-transducing) mutation, which greatly increases the frequ...) |
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'''Day 2''' | '''Day 2''' | ||
You should have colonies on some of your plates. To minimize the possibility of working with a double transductant, use colonies of the plate that used the most diluted P22. | You should have colonies on some of your plates. To minimize the possibility of working with a double transductant, use colonies of the plate that used the most diluted P22. While ''int'' P22 cannot form turn lysogens, pseudolysogens can occur. We can distinguish phage-cured transducatants from pseudolysognens by streaking on green agar plates. Phage free colonies are light green, while psedolysogens are dark blue-green. | ||
While ''int'' P22 cannot form turn lysogens, pseudolysogens can occur. We can distinguish phage-cured transducatants from pseudolysognens by streaking on green agar plates. Phage free colonies are light green, while psedolysogens are dark blue-green. | |||
#Streak a desired number of colonies onto green agar plates. I typically pick four for routine strain construction. | #Streak a desired number of colonies onto green agar plates. I typically pick four for routine strain construction. | ||
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This agar contains excess glucose, which is fermented by the ''Salmonella'' growing on the plate, producing large amounts of acid. In colonies of pseudolysogens, some cells will lyse, and the pH indicator in the plate will cause the agar to turn dark blue-green. | This agar contains excess glucose, which is fermented by the ''Salmonella'' growing on the plate, producing large amounts of acid. In colonies of pseudolysogens, some cells will lyse, and the pH indicator in the plate will cause the agar to turn dark blue-green. | ||
Recipe: | '''Recipe:''' | ||
Green agar base: | Green agar base: | ||
