∞ generated and posted on 2016.02.20 ∞
A volume within which immobilized cells have been lost due to virus action.
More broadly, plaques can be caused, for example, by bdellovibrios and equivalent predatory organisms with limited mobility especially within agar-based media.
Figure legend: Plaques of the bacteriophage T4 on an E. coli lawn. Two types of plaques are seen, both wild type and what is known as an r mutant (rI, specifically). Note that in a few cases wild-type plaques (small) and mutant plaques (large) are colliding. An equivalent phenomenon can be seen also in the paper by Hershey and Rotman as published in the journal Genetics in 1949 .
For additional discussion especially of phage plaques, click here.