Happy New Year! Before we move to the dark side of bacteriophages, the bioinformatic side, I thought one more question about plaque morphology could be appropriate. Here is a photo of plaques (on M. smeg) of Mycobacteriophage Spartacus that have been incubated for 5 days. After 24 hours of incubation, there were ~ 40 cloudy plaques, each with an estimated diameter of about 3mm. Here, at 5 days, you see a central clearer zone of lysis, with a surrounding cloudy area that at times measures at least 1 cm . In addition, there is a spray of tiny clearer plaques (indicated by red arrows) emanating from the center of the original plaque, but typically in only one direction. Can you explain this morphology?

Click for full-size image.