| Plaque Notes | The plaque size varies between 2mm-4mm. All plaques have clear area of lysis and most show an asymmetrical ring of turbidity around the outside of the clear portion. Roscoe grows at 30, 37, and 42 degrees Celsius. At 37, the average plaque size is 1-2mm larger than when grown at 30 but the turbid ring is the same size. At 42, the average plaque size increases by another 1-2mm from 37, and the turbid ring becomes much larger. When tested at 30 degrees with varying concentrations of CaCl2 in top augur and bacterial cells, no change in growth was noticed. At high enough concentrations, Roscoe shows a density dependent effect observed as a multitude of pinprick sized plaques covering the plate with a number of larger plaques throughout. |
