I must experimentally demonstrate beyond any doubt that isolated phages are lytic and not lysogenic... Of course, if the phage DNA is sequenced, one can look for the presence of integrase gene(s)... however, in the actual state of pandemics, it is absolutely impossible for me to have the phage's DNA sequenced at this time! Hence, can anyone help me with this issue? HOW CAN I EXPERIMENTALLY DEMONSTRATE THAT THE PHAGES I HAVE ISOLATED AND CHARACTERIZED ARE LYTIC AND NOT LYSOGENIC? Is there a test I can perform in the lab to make such a distinction?
Two effective methods are, lysogenic phages will form turbid plaques and its genome contain integrases and repressor proteins.
Phage microbiologists discovered decades ago that lysogenic phages make turbid plaques, by contrast to lytic phages, which make clear plaques. However, trubid plaques don't necessarily mean that the phage is lysogenic. See for example filamentous single-strand DNA phages such as fd or M13. Cells infected by such phages don't lyse, but chronically shed phage particles and show a reduced growth rate, hence the appearance of turbid plaques.
I don't see the purpose of sequencing the phage DNA to find out whether a phage is lytic or lysogenic. First, not finding a gene related to known integrases doesn't prove that there is no such gene belonging to an as yet undescribed integrase family. Second, even if a gene related to other integrases is found, there is no proof that the gene is functional and the phage may thus behave as a lytic phage, even if it may derive from a phage that was originally lysogenic.
@pierrebeguin ,your are totally right,still this confusion will sustain in phage biology until new guidelines to distinguish between lytic or lysogenic phage form.
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