Article

Enumeration of bacteriophages by double agar overlay plaque assay

Public Health Agency of Canada, Laboratory for Foodborne Diseases, Guelph, Ontario, Canada.
Methods in Molecular Biology (Impact Factor: 1.29). 02/2009; 501:69-76. DOI: 10.1007/978-1-60327-164-6_7
Source: PubMed

ABSTRACT The determination of the concentration of infectious phage particles is fundamental to many protocols in phage biology, genetics, and molecular biology. In this chapter the classical overlay protocol is described.

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    • "Freezing Containe r (Thermo Scientific, US) at a chamber temperature of À80 °C (cooling rate of À1 °C/min) without a nucleation step, and kept at À80 °C for 24 h. For each independent freeze-thaw assay, two ampoules of each condition were thawed at 25 °C and phage titer was determined by the soft agar overlay method in LB agar medium [8]. For lyophilization assays, frozen samples were dehydrated in a Heto FD4 model tray type freeze-dryer (LabEquipment, Denmark) at a condenser temperat ure of À50 °C for 48 h (pressure <1 Pa). "
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