Lytic plaques

The in vitro and in vivo effects of sulphated PS were also investigated against the pseudorabies virus (Suid HSV-1), the most notable of which is porcine HSV which has a well-documented history of epizootic infections, especially in Europe [105], In vitro experiments revealed that sulphated PS significantly reduced the number of lytic plaques, but in vivo only heparin protected mice against the pseudorabies virus. 

When a temperate phage is mixed with sensitive indicator bacteria and plated as described above, the reaction at each focus of infection is generally a combination of lytic and lysogenic responses. Some bacteria will be lysed and produce phage, others will survive as lysogenic cells, and the plaque becomes visible as a partial area of clearing in the bacterial lawn. It is possible to pick off cells from the central areas of these plaques and demonstrate that they carry prophage. 

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