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Growth of bacteriophage, titering, and transduction.

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Bacteria must express the maltose receptor:

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Under poor growth conditions, the lysogenic pathway is followed:

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Under good growth conditions, the lytic pathway is favored:

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Progeny phage are released from lysed bacteria:

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PLAQUE GROWTH

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Plaques enlarge by successive rounds of infection and lysis:

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The extent of plaque formation depends on the Multiplicity of Infection (M.O.I.):

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TRANSDUCTION

Conditions are chosen to promote lysogeny:

• Adsorb phage to DM700 at lower temperature (30? C)
• Grow bacteria on poor media (Minimal A glucose)
• Incubate plates at lower temperature (30? C)

Grow transductants under selective conditions, in our case we select for the ability to grow on media lacking cysteine

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DATA TABULATION

Count the number of PFUs (or CFUs) on a series of plates:

Calculate the number of PFU (or CFU) per mL of phage stock

For example: 37 plaques were observed.

Hence, (37 plaques / 0.1 ml) x 10^6 dilution = 3.7 x 10^8 PFU / mL of original phage stock.

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